CiteULike: Author Syed

Molecular Technology in Context: A Current Review of Diagnosis and Management of Infective Endocarditis

Faisal Syed — 2008-07-24T10:58:15-00:00

Progress in Cardiovascular Diseases, Vol. 50, No. 3. ( 2007), pp. 181-197.

Infective endocarditis is an evolving disease that presents as a great a problem to physicians, cardiologists, microbiologists, and cardiac surgeons in both the developed and developing world now as at any time over the past 3 decades. This article provides the reader with an up-to-date review of epidemiology, etiology, pathogenesis, presentation, diagnosis, and treatment. A major area of ongoing work is an approach to the culture-negative patient resulting in expanding diagnostic techniques. Limitations of current diagnostic strategies are detailed with focus on the use of the polymerase chain reaction to aid diagnosis. The technique offers several advantages, including extreme sensitivity and the opportunity for early diagnosis. Three general circumstances exist in which molecular approaches may be used: (1) identification of agents in cases of culture-negative infective endocarditis; (2) characterization of cultured agent(s) to determine clinical significance; (3) determination of antibiotic resistance. It should be recognized that there are limitations and certain quality assurance measures that should be implemented for optimal use of such methods. However, when executed properly and interpreted in the correct clinical and laboratory context, the incorporation of molecular diagnostics as a major Duke diagnostic criterion has been proposed with widespread support, although it is unlikely to supersede blood cultures as a primary diagnostic tool.

Pharmacological Interventions for Clozapine-induced Hypersalivation

Syed — 2008-07-22T18:40:43-00:00

Schizophr Bull, Vol. 34, No. 4. (1 July 2008), pp. 611-612.

10.1093/schbul/sbn043

Eradication of house dust mite from homes of atopic asthmatic subjects: a double-blind trial.

T Htut — 2008-07-03T02:33:56-00:00

The Journal of allergy and clinical immunology, Vol. 107, No. 1. (January 2001), pp. 55-60.

BACKGROUND: House dust mite (HDM) allergens can accumulate to very high levels in homes. From the observed sensitivity of HDMs to heat and their allergens to steam, a novel treatment of furnishings has been developed. OBJECTIVE: We sought to determine whether combined steam and heat treatment of home furnishings reduced asthmatic patients' bronchial hyperreactivity (BHR) and lowered HDM antigen loads. METHODS: The homes of 30 asthmatic subjects aged 18 to 45 years were randomly allocated into 3 groups. In groups 1 and 2 mattresses and duvets were treated with hot air (110 degrees C), followed by steam and then heat again. All their carpets were steam cleaned. Group 2 also had a special ventilation system installed above each patient's bedroom. The homes of subjects in group 3 were sham treated. Neither patient nor laboratory staff was aware of the types of treatment. Der p 1 and 2 levels in the household dust from the lounge, bedroom carpet, and beds were determined before and after treatment and then at 6 and 12 months. BHR, measured by using histamine PD(20) values, was recorded during the 4-week run-in period and at 3, 6, 9, 12 months after treatment. RESULTS: Active heat-steam treatment of homes caused a sustained reduction of Der p 1 (P =.003) and Der p 2 (P =.001) compared with no change in sham-treated group 3 homes. Patients whose homes were treated showed a 4-fold reduction in BHR at 9 months in group 1 and throughout the posttreatment period in group 2. No change was observed in the asthmatic subjects whose homes were not treated. These improvements were sustained for 12 months in the homes with bedroom ventilation units. CONCLUSIONS: A single treatment of home furnishings reduced mite allergen load to below the risk level for sensitization and improved the asthmatic patients' BHR by 4-fold.

Fluvastatin Inhibits Hepatitis C Replication in Humans

Bader — 2008-06-12T08:07:26-00:00

The American Journal of Gastroenterology, Vol. 103, No. 6. (June 2008), pp. 1383-1389.

Time Synchronization for High Latency Acoustic Networks

AA Syed — 2008-06-09T17:56:01-00:00

INFOCOM 2006. 25th IEEE International Conference on Computer Communications. Proceedings (2006), pp. 1-12.

Pertussis-associated hospitalizations in American Indian and Alaska Native infants.

TV Murphy — 2008-06-05T06:02:28-00:00

The Journal of pediatrics, Vol. 152, No. 6. (June 2008), pp. 839-843.

OBJECTIVE: To investigate the burden of pertussis in American Indian and Alaska Native (AI/AN) infants. STUDY DESIGN: AI/AN pertussis-associated hospitalizations between 1980 and 2004 were evaluated using Indian Health Service (IHS)/tribal inpatient data, which include all reported hospitalizations within the IHS/tribal health care system. RESULTS: Between 1980 and 2004, 483 pertussis-associated hospitalizations in AI/AN infants were documented; 88% of cases involved infants age < 6 months. For this entire period, the average annual hospitalization rate was 132.7 per 100,000 AI/AN infants (95% confidence interval [CI] = 121.3 to 145.2), and 234.5 per 100,000 AI/AN infants age < 6 months (95% CI = 213.1 to 258.1). Between 2000 and 2004, the annual hospitalization rate was 100.5 per 100,000 AI/AN infants (95% CI = 81.6 to 123.7), which exceeds the estimated 2003 pertussis hospitalization rate of 67.7 per 100,000 in the general US infant population (95% CI = 61.9 to 73.5). The highest pertussis hospitalization rates in 2000 to 2004 were in AI/AN infants in the Alaska and Southwestern IHS regions of the United States. CONCLUSIONS: The burden of pertussis in AI/AN infants is high, particularly so in infants age < 6 months in the Alaska and the Southwestern IHS regions of the United States. Ensuring implementation of vaccination strategies to reduce the incidence of pertussis in AI/AN, infants, adolescents, and adults alike is warranted to reduce the burden of pertussis in AI/AN infants.

Efficiency of signalling through cytokine receptors depends critically on receptor orientation.

RS Syed — 2008-06-03T14:50:09-00:00

Nature, Vol. 395, No. 6701. (1 October 1998), pp. 511-516.

Human erythropoietin is a haematopoietic cytokine required for the differentiation and proliferation of precursor cells into red blood cells. It activates cells by binding and orientating two cell-surface erythropoietin receptors (EPORs) which trigger an intracellular phosphorylation cascade. The half-maximal response in a cellular proliferation assay is evoked at an erythropoietin concentration of 10 pM, 10(-2) of its Kd value for erythropoietin-EPOR binding site 1 (Kd approximately equal to nM), and 10(-5) of the Kd for erythropoietin-EPOR binding site 2 (Kd approximately equal to 1 microM). Overall half-maximal binding (IC50) of cell-surface receptors is produced with approximately 0.18 nM erythropoietin, indicating that only approximately 6% of the receptors would be bound in the presence of 10 pM erythropoietin. Other effective erythropoietin-mimetic ligands that dimerize receptors can evoke the same cellular responses but much less efficiently, requiring concentrations close to their Kd values (approximately 0.1 microM). The crystal structure of erythropoietin complexed to the extracellular ligand-binding domains of the erythropoietin receptor, determined at 1.9 A from two crystal forms, shows that erythropoietin imposes a unique 120 degrees angular relationship and orientation that is responsible for optimal signalling through intracellular kinase pathways.

NMR structure of human erythropoietin and a comparison with its receptor bound conformation.

JC Cheetham — 2008-06-02T21:11:54-00:00

Nature structural biology, Vol. 5, No. 10. (October 1998), pp. 861-866.

The solution structure of human erythropoietin (EPO) has been determined by nuclear magnetic resonance spectroscopy and the overall topology of the protein is revealed as a novel combination of features taken from both the long-chain and short-chain families of hematopoietic growth factors. Using the structure and data from mutagenesis studies we have elucidated the key physiochemical properties defining each of the two receptor binding sites on the EPO protein. A comparison of the NMR structure of the free EPO ligand to the receptor bound form, determined by X-ray crystallography, reveals conformational changes that may accompany receptor binding.

The Design of Discovery Net: Towards Open Grid Services for Knowledge Discovery

Salman Alsairafi — 2008-04-27T18:54:54-00:00

International Journal of High Performance Computing Applications, Vol. 17, No. 3. (1 August 2003), pp. 297-315.

With the emergence of distributed resources and grid technologies there is a need to provide higher level informatics infrastructures allowing scientists to easily create and execute meaningful data integration and analysis processes that take advantage of the distributed nature of the available resources. These resources typically include heterogeneous data sources, computational resources for task execution and various application-specific services. The effort of the high performance community has so far mainly focused on the delivery of low-level informatics infrastructures enabling the basic needs of grid applications. Such infrastructures are essential but do not directly help end-users in creating generic and re-usable applications. In this paper, we present the Discovery Net architecture for building grid-based knowledge discovery applications. Our architecture enables the creation of high-level, re-usable and distributed application workflows that use a variety of common types of distributed resources. It is built on top of standard protocols and standard infrastructures such as Globus but also defines its own protocols such as the Discovery Process Mark-up Language for data flow management. We discuss an implementation of our architecture and evaluate it by building a real-time genome annotation environment on top. 10.1177/1094342003173003

Circulating Mononuclear Cells in the Obese Are in a Proinflammatory State

Husam Ghanim — 2008-04-17T23:10:03-00:00

Circulation, Vol. 110, No. 12. (21 September 2004), pp. 1564-1571.

Background-- In view of the increase in plasma concentrations of proinflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and C-reactive protein (CRP) in obesity, we investigated whether peripheral blood mononuclear cells (MNC) from obese subjects are in a proinflammatory state. Methods and Results-- MNC were prepared from fasting blood samples of obese (n=16; body mass index [BMI]=37.7+/-5.0 kg/m2) and normal-weight control (n=16; BMI=23.8+/-1.9 kg/m2) subjects. Nuclear factor kappaB (NF-kappaB) binding to DNA in nuclear extracts was elevated (P<0.05) and the inhibitor of NFkappaB-beta (IkappaB-beta) was significantly lower (P<0.001) in the obese group. Reverse transcription-polymerase chain reaction revealed elevated levels of migration inhibitor factor (MIF), IL-6, TNF-alpha, and matrix metalloproteinase-9 (MMP-9) mRNA expression in the obese subjects (P<0.05). Plasma concentrations of MIF, IL-6, TNF-alpha, MMP-9, and CRP were also significantly higher. Plasma glucose, insulin, and free fatty acids (FFAs) were measured, and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Plasma FFA concentration related significantly to BMI, IL-6, and TNF-alpha mRNA expression and plasma CRP levels but not to HOMA-IR. On the other hand, the inflammatory mediators were significantly related to BMI and HOMA-IR. Conclusions-- These data show (1) for the first time that MNC in obesity are in a proinflammatory state with an increase in intranuclear NF-kappaB binding, a decrease in IkappaB-beta, and an increase in the transcription of proinflammatory genes regulated by NF-kappaB; (2) that plasma FFAs are a modulator of inflammation; and (3) that insulin resistance is a function of inflammatory mediators. 10.1161/01.CIR.0000142055.53122.FA

Evolutionary analysis of enzymes using Chisel.

AA Rodriguez — 2008-03-19T01:18:14-00:00

Bioinformatics, Vol. 23, No. 22. (15 November 2007), pp. 2961-2968.

MOTIVATION: Availability of large volumes of genomic and enzymatic data for taxonomically and phenotypically diverse organisms allows for exploration of the adaptive mechanisms that led to diversification of enzymatic functions. We present Chisel, a computational framework and a pipeline for an automated, high-resolution analysis of evolutionary variations of enzymes. Chisel allows automatic as well as interactive identification, and characterization of enzymatic sequences. Such knowledge can be utilized for comparative genomics, microbial diagnostics, metabolic engineering, drug design and analysis of metagenomes. RESULTS: Chisel is a comprehensive resource that contains 8575 clusters and subsequent computational models specific for 939 distinct enzymatic functions and, when data is sufficient, their taxonomic variations. Application of Chisel to identification of enzymatic sequences in newly sequenced genomes, analysis of organism-specific metabolic networks, 'binning' of metagenomes and other biological problems are presented. We also provide a thorough analysis of Chisel performance with other similar resources and manual annotations on Shewanella oneidensis MR1 genome.

Java GUI for InterProScan (JIPS): A tool to help process multiple InterProScans and perform ortholog analysis

Aijazuddin Syed — 2006-10-21T02:17:18-00:00

BMC Bioinformatics, Vol. 7 (20 October 2006), 462.

Lack of reproducibility of assessment of aspirin responsiveness by optical aggregometry and two platelet function tests

Paul Harrison — 2008-02-26T09:46:45-00:00

Platelets, Vol. 19, No. 2. (2008), pp. 119-124.

The term aspirin-resistance describes the failure of aspirin to inhibit thromboxane A2 production. Many new tests have become available for potentially measuring aspirin responses but some are non-specific and do not isolate COX-1 activity. We previously demonstrated that agreement between two tests (PFA-100® and VerifyNow®-ASA) and light transmission aggregation (LTA) was no greater than would be expected by chance. In this study we re-tested the same patients using identical methods after 1 year to determine whether poor agreement might have been due to assessment in the acute phase and whether the results of the individual tests are consistent over time. Platelet function by all three tests was re-tested in the 72 patients who were alive and still receiving low dose ASA therapy one year after the first tests were performed. On re-testing the prevalence of ASA non-responsiveness compared with baseline was 10% vs 17% by the VerifyNow®-ASA test, 25% vs 22% by the PFA-100®, and 1% vs 5% by LTA. Agreement between the tests at 1 year remained poor (kappas: 0.02–0.17) and only one patient was identified as a non-responder by all three tests, in keeping with the theoretical differences between the tests. Within test comparisons of baseline vs 1 year showed moderate agreement for the PFA-100® (kappa = 0.44, 95% CI 0.19–0.68, p = 0.0006), a fair agreement for VerifyNow®-ASA (kappa = 0.34, 0.04–0.64, p = 0.12) and poor agreement for LTA (kappa = 0.14, -0.11 -0.39, p = 0.24 for ADP; kappa = 0.09, -0.21–0.39, p = 0.41 for arachidonic acid). Agreement between the three tests in identifying aspirin non-responsiveness remained poor in patients who had been taking aspirin for at least 1 year follow-up. Reproducibility over time was no greater than chance for LTA and only moderate for VerifyNow®-ASA and PFA-100®. Lack of consistency over time in identification of apparently non-responsiveness individuals is likely to substantially undermine any ability of these tests to predict risk of recurrent vascular events.

Listen to your Data: Model-Based Sonification for Data Analysis

T Hermann — 2008-01-30T09:58:39-00:00

Sonification is the use of non-speech audio to convey information. We are developing tools for interactive data exploration, which make use of sonification for data presentation. In this paper, model-based sonification is presented as a concept to design auditory displays. Two designs are described: (1) particle trajectories in a "data potential" is a sonification model to reveal information about the clustering of vectorial data and (2) "data-sonograms" is a sonification for data from a...

An identified central pattern-generating neuron co-ordinates sensory-motor components of respiratory behavior in Lymnaea.

Z Haque — 2008-01-30T06:51:31-00:00

Eur J Neurosci, Vol. 23, No. 1. (January 2006), pp. 94-104.

Defining the attributes of individual central pattern-generating (CPG) neurons underlying various rhythmic behaviors are fundamental to our understanding of how the brain controls motor programs, such as respiration and locomotion. To this end, we have explored a simple invertebrate preparation in which the neuronal basis of respiratory rhythmogenesis can be investigated from the whole animal to a single cell level. An identified dopaminergic neuron, termed right pedal dorsal 1 (RPeD1), is a component of the CPG network which controls hypoxia-driven, aerial respiration in the fresh water snail Lymnaea stagnalis. Using intact, semi-intact and isolated brain preparations, we have discovered that in addition to its role as a respiratory CPG neuron, RPeD1 co-ordinates sensory-motor input from the pneumostome (the respiratory orifice) at the water/air interface to initiate respiratory rhythm generation. An additional, novel role of RPeD1 was also found. Specifically, direct intracellular stimulation of RPeD1 induced pneumostome openings, in the absence of motor neuronal activity. To determine further the role of RPeD1 in the respiratory behavior of intact animals, either its axon was severed or the soma selectively killed. Many components of the respiratory behavior in the intact animals were found to be perturbed following RPeD1 axotomy or 'somatomy' (soma removed). Taken together, the data presented provide a direct demonstration that RPeD1 is a multifunctional CPG neuron, which also serves many additional roles in the control of breathing behavior, ranging from co-ordination of mechanosensory input to the motor control of the respiratory orifice.

Changes in the activity of a CpG neuron after the reinforcement of an operantly conditioned behavior in Lymnaea.

GE Spencer — 2008-01-30T06:46:41-00:00

J Neurophysiol, Vol. 88, No. 4. (October 2002), pp. 1915-1923.

We have previously shown that the aerial respiratory behavior of the mollusk Lymnaea stagnalis can be operantly conditioned, and the central pattern generating (CPG) neurons underlying this behavior have been identified. As neural correlates of operant conditioning remain poorly defined in both vertebrates and invertebrates, we have used the Lymnaea respiratory CPG to investigate neuronal changes associated with the change in behavior after conditioning. After operant conditioning of the intact animals, semi-intact preparations were dissected, so that changes in the respiratory behavior (pneumostome openings) and underlying activity of the identified CPG neuron, right pedal dorsal 1 (RPeD1), could be monitored simultaneously. RPeD1 was studied because it initiates the rhythmic activity of the CPG and receives chemo-sensory input from the pneumostome area. Pneumostome openings and RPeD1 activity were monitored both before and after a reinforcing training stimulus applied to the open pneumostome of operantly conditioned and yoked control preparations. After presentation of the reinforcing stimulus, there was a significant reduction in both breathing behavior and RPeD1 activity in operant preparations but not in yoked and naïve controls. Furthermore these changes were only significant in the subgroup of operantly conditioned animals described as good learners and not in poor learners. These data strongly suggest that changes in RPeD1 activity may underlie the behavioral changes associated with the reinforcement of operant conditioning of the respiratory behavior.

Neural changes after operant conditioning of the aerial respiratory behavior in Lymnaea stagnalis.

GE Spencer — 2008-01-30T06:30:28-00:00

J Neurosci, Vol. 19, No. 5. (1 March 1999), pp. 1836-1843.

In this study, we demonstrate neural changes that occurred during operant conditioning of the aerial respiratory behavior of Lymnaea stagnalis. Aerial respiration in Lymnaea occurs at the water interface and is achieved by opening and closing movements of its respiratory orifice, the pneumostome. This behavior is controlled by a central pattern generator (CPG), the neurons of which, as well as the motoneurons innervating the pneumostome, have previously been identified and their synaptic connections well characterized. The respiratory behavior was operantly conditioned by applying a mechanical stimulus to the open pneumostome whenever the animal attempted to breathe. This negative reinforcement to the open pneumostome resulted in its immediate closure and a significant reduction in the overall respiratory activity. Electrophysiological recordings from the isolated CNSs after operant conditioning showed that the spontaneous patterned respiratory activity of the CPG neurons was significantly reduced. This included reduced spontaneous activity of the CPG interneuron involved in pneumostome opening (input 3 interneuron) and a reduced frequency of spontaneous tonic activity of the CPG interneuron [right pedal dorsal 1 (RPeD1)]. The ability to trigger the patterned respiratory activity by electrical stimulation of RPeD1 was also significantly reduced after operant conditioning. This study therefore demonstrates significant changes within a CPG that are associated with changes in a rhythmic homeostatic behavior after operant conditioning.

Operant conditioning of aerial respiratory behaviour in Lymnaea stagnalis

K Lukowiak — 2008-01-30T06:26:24-00:00

J Exp Biol, Vol. 199, No. Pt 3. (1996), pp. 683-691.

In this study, we operantly conditioned the aerial respiratory behaviour of the freshwater snail Lymnaea stagnalis. Aerial respiration in Lymnaea stagnalis is accomplished by the spontaneous opening and closing of its respiratory orifice, the pneumostome, at the water surface. Weak tactile stimulation of the pneumostome area, when the pneumostome is open, evoked only the pneumostome closure response, which is one aspect of the escape-withdrawal reflex. Pneumostome stimulation resulted in its closure and the termination of aerial respiratory activity. A contingent tactile stimulation paradigm was used to operantly condition the animals. Stimulation of the pneumostome whenever the animal attempted to breathe resulted in significantly fewer attempts to open the pneumostome as training progressed. The latency of the first breath (subsequent to stimulation), the number of breaths and the total breathing time were measured before and after each training period. Significant, quantifiable changes in these behavioural parameters were observed only in the operant conditioning group animals. Control animals receiving tactile stimulation to their pneumostome not contingent upon pneumostome opening movements (yoked controls) or those that were physically prevented from surfacing to breathe (hypoxic controls), did not exhibit significant changes in these behavioural parameters. Our data provide the first direct evidence for operant conditioning of respiration in any animal.

Risk factors analysis for hepatocellular carcinoma in patients with and without cirrhosis: A casecontrol study of 213 hepatocellular carcinoma patients from India

Kumar — 2007-06-30T19:21:48-00:00

Journal of Gastroenterology and Hepatology, Vol. 22, No. 7. (July 2007), pp. 1104-1111.

Disruption of germ cell-Sertoli cell interactions leads to spermatogenic defects

V Syed — 2008-01-10T14:38:08-00:00

Molecular and Cellular Endocrinology, Vol. 186, No. 2. (25 January 2002), pp. 155-157.

In the aging human testis, partially regressed tubules contain Sertoli cells with an altered appearance and reduced numbers of germ cells. Investigating the effects of aging on Sertoli cell-germ cell interactions from Brown Norway rats, we have found that a selective breakdown in germ cell-Sertoli interactions could lead to severe reductions in male fertility. Previous studies have identified two specific inducible germ cell markers (a von Ebner's-like protein and the Huntington disease protein) and two specific inducible Sertoli cell markers (a sertonin receptor and a novel gene) that are expressed in Sertoli cell-germ cell cocultures and in vivo [Endocrinology 140 (1999a) 5754; J. Biol. Chem. 27 (1999b) 10737]. We find that germ cells from aged regressed testes are unable to respond to selective signals from Sertoli cells, although germ cells from aged normal sized testes respond well. Similarly, Sertoli cells from aged regressed testes fail to respond to certain signals from young germ cells. We propose that selective disruptions in communication between Sertoli cells and germ cells contribute to germ cell loss during aging.

Functional implications of neurotransmitter expression during axonal regeneration: serotonin, but not peptides, auto-regulate axon growth of an identified central neuron.

CE Koert — 2007-12-19T01:20:23-00:00

J Neurosci, Vol. 21, No. 15. (1 August 2001), pp. 5597-5606.

We studied the regenerative properties of one of two electrically coupled molluscan neurons, the serotonergic cerebral giant cells (CGCs) of Lymnaea stagnalis, after axotomy. The CGCs play a crucial role in feeding behavior, and when both cells are disconnected from their target neurons, animals no longer feed. When one CGC was permanently disconnected from its targets and the other was reversibly damaged by a nerve crush, the latter one regenerated over a period of 2 weeks to reform functional synapses with specific target neurons. At the same time, recovery of the feeding behavior was observed. After the crush, neuropeptide gene expression in the CGC was downregulated to approximately 50%. Serotonin synthesis, on the other hand, remained unaffected, suggesting that serotonin might have an active role in regeneration. In primary neuron culture, CGCs failed to extend neurites in the presence of serotonin; in cells that extended neurites in the absence of serotonin, focally applied serotonin, but not neuropeptides, induced growth cone collapse. Using serotonin-sensitive sniffer cells, we show that CGC neurites and growth cones release serotonin in culture. Finally, both the spontaneous and stimulation-induced release of serotonin from CGCs in culture resulted in growth cone collapse responses that could be blocked by the serotonin receptor antagonist methysergide. Our data suggest that auto-released serotonin is inhibitory to CGC neurite outgrowth in vitro. During regeneration in vivo, serotonin release might fine-tune axon guidance and branching by inducing local collapse responses in extending neurites.

Contemporary estimates of Pan-Arctic freshwater discharge from GRACE and reanalysis

TH Syed — 2007-11-14T05:39:24-00:00

Geophysical Research Letters, Vol. 34 (2007), L19404.

Somatostatin receptors signal through EFA6A-ARF6 to activate phospholipase D in clonal beta-cells.

JA Grodnitzky — 2007-11-13T15:55:52-00:00

J Biol Chem, Vol. 282, No. 18. (4 May 2007), pp. 13410-13418.

Somatostatin (SS) is a peptide hormone that inhibits insulin secretion in beta-cells by activating its G(i/o)-coupled receptors. Our previous work indicated that a betagamma-dimer of G(i/o) coupled to SS receptors can activate phospholipase D1 (PLD1) (Cheng, H., Grodnitzky, J. A., Yibchok-anun, S., Ding, J., and Hsu, W. H. (2005) Mol. Pharmacol. 67, 2162-2172). The aim of the present study was to elucidate the mechanisms underlying SS-induced PLD activation. We demonstrated the presence of ADP-ribosylation factor Arf1 and Arf6 in clonal beta-cells, HIT-T15. We also determined that the activation of PLD1 was mediated through Arf6. Overexpression of dominant-negative (dn) Arf6 mutant, Arf6(T27N), and suppression of mRNA levels using siRNA, both abolished SS-induced PLD activation, while overexpression of wild type Arf6 further enhanced this PLD activation. In contrast, overexpression of dn-Arf1 mutant Arf1(T31N) or dn-Arf5 mutant Arf5(T31N) failed to reduce SS-induced PLD activation. These findings suggested that Arf6, but not Arf1 or Arf5, mediates the effect of SS. We further determined the involvement of the Arf6 guanine nucleotide exchange factor (GEF) EFA6A, a GEF previously thought to be found predominantly in the brain, in the activation of PLD1 in HIT-T15 cells. Using Northern and Western blot analyses, both mRNA and protein of EFA6A were found in these cells. Overexpression of dn-EFA6A mutant, EFA6A(E242K), and suppression of mRNA levels using siRNA, both abolished SS-induced PLD activation, whereas overexpression of dn-EFA6B mutant, EFA6B(E651K), failed to reduce SS-induced PLD activation. In addition, overexpression of dn-ARNO mutant, ARNO(E156K), another GEF of Arf6, had no effect on SS-induced activation of PLD. Taken together, these results suggest that SS signals through EFA6A to activate Arf6-PLD cascade.

Population pharmacokinetics, brain distribution, and pharmacodynamics of 2(nd) generation dopamine transporter selective benztropine analogs developed as potential substitute therapeutics for treatment of cocaine abuse.

Shariq A Syed — 2007-11-12T01:06:49-00:00

J Pharm Sci (19 September 2007)

A second generation of N-substituted 3alpha-[bis(4'-fluorophenyl)methoxy]-tropanes (GA 1-69, JHW 005 and JHW 013) binds with high affinity to the dopamine transporter (DAT) and are highly selective toward DAT compared to muscarinic receptor binding (M(1)). The objective of this study was to characterize brain distribution, pharmacokinetics, and pharmacodynamics [extracellular brain dopamine (DA) levels] of three novel N-substituted benztropine (BZT) analogs in male Sprague-Dawley rats. The BZT analogs displayed a higher distribution (V(d) = 8.69-34.3 vs. 0.9 L/kg) along with longer elimination (t(1/2): 4.1-5.4 vs. 0.5 h) than previously reported for cocaine. Brain-to-plasma partition coefficients were 1.3-2.5 vs. 2.1 for cocaine. The effect of the BZT analogs on extracellular brain (DA) levels ranged from minimal effects (GA 1-69) to several fold elevation ( approximately 850% of basal DA for JHW 013) at the highest dose evaluated. PK/PD analysis of exposure-response data resulted in lower IC(50) values for the BZT analogs compared to cocaine indicating their higher potency to inhibit DA reuptake (0.1-0.3 vs. 0.7 mg/L). These BZT analogs possess significantly different PK and PD profiles as compared to cocaine suggesting that further evaluation as cocaine abuse therapeutics is warranted. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci.

Transport, metabolism, and in vivo population pharmacokinetics of the chloro benztropine analogs, a class of compounds extensively evaluated in animal models of drug abuse.

AA Othman — 2007-08-21T21:23:40-00:00

J Pharmacol Exp Ther, Vol. 320, No. 1. (January 2007), pp. 344-353.

Recently, extensive behavioral research has been conducted on the benztropine (BZT) analogs with the goal of developing successful therapeutics for cocaine abuse. The present study was conducted to characterize the contribution of dispositional factors in mediating the behavioral differences among the chloro BZT analogs and to identify cytochrome P450 enzymes involved in their metabolism. Bidirectional transport and efflux studies of four of the chloro BZT analogs were conducted. Screening with a panel of human and rat Supersomes was performed for 4',4”-diCl BZT. In addition, pharmacokinetic and brain distribution studies for 4'-Cl and 4',4”-diCl BZT in Sprague-Dawley rats were conducted. The permeability of the chloro analogs ranged from 8.26 to 32.23 and from 1.37 to 21.65 x 10(-6) cm/s, whereas the efflux ratios ranged from 2.1 to 6.9 and from 3.3 to 28.4 across Madin-Darby canine kidney-multidrug resistance 1 (MDCK-MDR1) and Caco-2 monolayers, respectively. The P-glycoprotein (P-gp) inhibitor verapamil reduced the efflux ratios and enhanced the absorptive transport of the chloro BZT analogs. 4',4”-diCl BZT was a substrate of human CYP2D6 and 2C19 and rat 2C11 and 3A1. The brain uptake for 4'-Cl and 4',4”-diCl BZT was comparable and higher than previously reported for cocaine (brain-to-plasma partition coefficient = 4.6-4.7 versus 2.1 for cocaine). The rank order for t(1/2) was 4',4”-diCl BZT >> 4'-Cl BZT > cocaine and for steady-state volume of distribution was 4'-Cl BZT > 4',4”-diCl BZT >> cocaine. In conclusion, the chloro analogs differ significantly in their clearance and duration of action, which correlates to their behavioral profiles and abuse liability. Furthermore, these results suggest that the distinctive behavioral profile of these analogs is not due to limited brain exposure.

Genetic diversity analysis in Vicia species using retrotransposon-based SSAP markers

Alberto Sanz — 2007-08-06T08:45:54-00:00

Molecular Genetics and Genomics

Abstract Twelve different Ty1-copia and Ty3-gypsy group LTR retrotransposons were compared for their usefulness in SSAP marker development in two agriculturally important Vicia species. Three of the retrotransposons, PDR1, Tps19 and Tvf4, yielded useful SSAP marker systems in V. faba, and V. narbonensis. Another, Tvf1 was a good source of SSAP markers in V. narbonensis alone. The optimized SSAP marker systems were applied to the analysis of two diverse Vicia germplasm sets. Two hundred and two polymorphic Tvf1 SSAP markers were scored in 56 V. narbonensis samples and 196 polymorphic markers derived from the other three most useful retrotransposons were scored in a collection of 20 V. faba samples. The marker data were then used to construct phylogenetic trees. The trees for both species tend to show long-branch lengths, with rather little fine structure. Some V. narbonensis accessions cluster by geographical origin but many do not and a given geographical region is often represented by multiple diverse groups in the tree, suggesting a deep and ancient structure for the diversity of V. narbonensis that spans its current geographic range. The tree for the V. faba accessions also shows very limited clustering with geographical origin and no obvious correlation between diversity and morphology-based taxonomic groupings for the species.

Kinesin and dynein move a peroxisome in vivo: a tug-of-war or coordinated movement?

C Kural — 2005-08-26T21:46:28-00:00

Science, Vol. 308, No. 5727. (3 June 2005), pp. 1469-1472.

We used fluorescence imaging with one nanometer accuracy (FIONA) to analyze organelle movement by conventional kinesin and cytoplasmic dynein in a cell. We located a green fluorescence protein (GFP)-tagged peroxisome in cultured Drosophila S2 cells to within 1.5 nanometers in 1.1 milliseconds, a 400-fold improvement in temporal resolution, sufficient to determine the average step size to be approximately 8 nanometers for both dynein and kinesin. Furthermore, we found that dynein and kinesin do not work against each other in vivo during peroxisome transport. Rather, multiple kinesins or multiple dyneins work together, producing up to 10 times the in vitro speed.

MiNT-m: an autonomous mobile wireless experimentation platform

Pradipta De — 2007-07-20T13:04:23-00:00

(2006), pp. 124-137.

High mobility AlGaN/GaN heterostructures grown by plasma-assisted molecular beam epitaxy on semi-insulating GaN templates prepared by hydride vapor phase epitaxy

MJ Manfra — 2007-07-12T13:02:04-00:00

Journal of Applied Physics, Vol. 92, No. 1. (2002), pp. 338-345.

We report on an extensive study of the growth and transport properties of the two-dimensional electron gas (2DEG) confined at the interface of AlGaN/GaN heterostructures grown by molecular beam epitaxy (MBE) on thick, semi-insulating GaN templates prepared by hydride vapor phase epitaxy (HVPE). Thick (~20 µm) GaN templates are characterized by low threading dislocation densities (~5×108 cm–2) and by room temperature resistivities of ~108 cm. We describe sources of parasitic conduction in our structures and how they have been minimized. The growth of low Al containing (x0.05) AlxGa1-xN/GaN heterostructures is investigated. The use of low Al containing heterostructures facilitates the study of the 2DEG transport properties in the previously unexplored regime of carrier density ns2×1012 cm–2. We detail the impact of MBE growth conditions on low temperature mobility. Using an undoped HVPE template that was residually n type at room temperature and characterized an unusually low dislocation density of ~2×108 cm–2, we have grown an Al0.05Ga0.95N/GaN heterostructure with a record mobility of 75 000 cm2/V s at sheet density of 1.5×1012 cm–2 and T = 4.2 K. The same heterostructure design grown on a semi-insulating HVPE template yielded a peak mobility of 62 000 cm2/V s at a density of ns = 1.7×1012 cm–2 and T = 4.2 K. The observation of the fractional quantum Hall effect at filling factor = 5/3 in the AlGaN/GaN system is reported. It is also demonstrated that thick semi-insulating GaN templates grown by HVPE are a viable substrate for the growth of high electron mobility transistors. Typical Al0.25Ga0.75N/GaN heterostructures exhibit room temperature density of 1.0×1013 cm–3 and mobility of ~1500 cm2/V s. The dc and rf characteristics of transistors grown by MBE on a HVPE template are presented. ©2002 American Institute of Physics.

Psoralen photobiology and photochemotherapy: 50 years of science and medicine.

D Bethea — 2007-07-06T16:04:37-00:00

J Dermatol Sci, Vol. 19, No. 2. (February 1999), pp. 78-88.

In 1998 it is appropriate to commemorate the 50th anniversary of el Mofty's use of purified 8-methoxypsoralen (8-MOP) in the treatment of vitiligo (el Mofty AM. A preliminary clinical report on the treatment of leukoderma with Ammi majus linn. J R Egypt Med Assn 1948,31:651 65. el Mofty AM, el Sawalhy H, el Mofty M. Clinical study of a new preparation of 8-methoxypsoralen in photochemotherapy. Int J Dermatol 1994;8:588 92). Two young American dermatologists (Aaron Lerner and Thomas Fitzpatrick) were intrigued by the potency of this material. After Lerner determined that artificial long wavelength ultraviolet (320-400 nm, UVA) radiation was the most efficient for activating 8-MOP. the development of artificial sources enabled the efficient delivery of these photons to skin containing 8-MOP. Their initial studies for vitiligo led to further development of this therapy for the treatment of psoriasis (Parrish JA, Fitzpatrick TB, Tannenbaum L, et al. Photochemotherapy of psoriasis with oral methoxsalen and long-wave ultraviolet light. New Engl J Med 1974;291:1207-11. Honigsmann H, Fitzpatrick TB, Pathak MA, et al. Oral photochemotherapy with psoralen and UVA (PUVA): principles and practice. In: Fitzpatrick TB, Eisen AZ, Wolf K, editors. Dermatology in General Medicine. New York: McGraw-Hill, 1987:1728-54). This photochemotherapy came to be called 'PUVA' (psoralen + UVA). The position PUVA holds today as one of the most common procedures performed in dermatology can be traced to their initial curiosity and their subsequent ingenuity. Further developments in more recent years capitalized on their seminal work. The therapy met with unprecedented success from the outset, leaving little perceived need to understand underlying science. However, in recent years there has been a new found interest in the basic aspects of psoralen photobiology and molecular mechanistic events contributing to therapeutic responses as well as to the development of skin cancers in PUVA patients. These will be surveyed in this review commemorating the 50 years of modern psoralen photobiology and photomedicine.

On Optimality of Beamforming for Multiple Antenna Systems with Imperfect Feedback

A Syed — 2007-05-29T19:55:03-00:00

(2001)

We determine a necessary and sucient condition under which beamforming achieves Shannon capacity in a narrowband point to point communication system employing multiple transmit antennas and a single receive antenna. We assume perfect channel state information at the receiver (CSIR) and imperfect channel state feedback from the receiver to the transmitter. We consider the cases of mean and covariance feedback. The channel is modeled at the transmitter as a vector of complex jointly Gaussian...

Innovative therapies for prostate cancer treatment.

S Syed — 2007-05-07T14:33:12-00:00

Rev Urol, Vol. 5 Suppl 3 (2003)

Androgen ablation is effective therapy for metastatic prostate cancer, but the majority of men eventually become refractory to this intervention. Cytotoxic chemotherapy offers palliation to symptomatic patients with hormone-refractory prostate cancer (HRPC); however, no chemotherapy regimen has yet been shown to prolong survival. There is a clear need for new agents and drug targets for the treatment of HRPC. A number of innovative therapeutic approaches that are rationally based and target driven are under investigation. This article reviews the development of antisense oligonucleotides that inhibit the anti-apoptotic bcL-2 protein. Approaches that target the epidermal growth factor receptor, the platelet derived growth factor receptor, and nuclear factor kappa-B are also discussed. There is much expectation that these therapies alone or in combination with cytotoxic chemotherapy will impact the clinical outcome of patients with HRPC.

Contrasting effects of ischemia on the kinetics of membrane voltage and intracellular calcium transient underlie electrical alternans.

V Lakireddy — 2007-04-09T12:00:04-00:00

Am J Physiol Heart Circ Physiol, Vol. 288, No. 1. (January 2005)

Repolarization alternans has been considered a strong marker of electrical instability. The objective of this study was to investigate the hypothesis that ischemia-induced contrasting effects on the kinetics of membrane voltage and intracellular calcium transient (Ca(i)T) can explain the vulnerability of the ischemic heart to repolarization alternans. Ischemia-induced changes in action potential (AP) and Ca(i)T resulting in alternans were investigated in perfused Langendorff guinea pig hearts subjected to 10-15 min of global no-flow ischemia followed by 10-15 min of reperfusion. The heart was stained with 100 microl of rhod-2 AM and 25 microl of RH-237, and AP and Ca(i)T were simultaneously recorded with an optical mapping system of two 16 x 16 photodiode arrays. Ischemia was associated with shortening of AP duration (D) but delayed upstroke, broadening of peak, and slowed decay of Ca(i)T resulting in a significant increase of Ca(i)T-D. The changes in APD were spatially heterogeneous in contrast to a more spatially homogeneous lengthening of Ca(i)T-D. Ca(i)T alternans could be consistently induced with the introduction of a shorter cycle when the upstroke of the AP occurred before complete relaxation of the previous Ca(i)T and generated a reduced Ca(i)T. However, alternans of Ca(i)T was not necessarily associated with alternans of APD, and this was correlated with the degree of spatially heterogeneous shortening of APD. Sites with less shortening of APD developed alternans of both Ca(i)T and APD, whereas sites with greater shortening of APD could develop a similar degree of Ca(i)T alternans but slight or no APD alternans. This resulted in significant spatial dispersion of APD. The study shows that the contrasting effects of ischemia on the duration of AP and Ca(i)T and, in particular, on their spatial distribution explain the vulnerability of ischemic heart to alternans and the increased dispersion of repolarization during alternans.

Incremental learning with support vector machines

N Syed — 2006-08-27T16:27:13-00:00

International Joint Conference on Artificial Intelligence (1999)

As real-world databases increase in size, there is a need to scale up inductive learning algorithms to handle more training data. Incremental learning techniques are one possible solution to the scalability problem, where data is processed in parts, and the result combined so as to use less memory. Support Vector Machines (SVMs) have worked well for the batch mode learning and have shown impressive performance in many practical applications. They also have nice properties for...

An International Survey of Hospital Practice in the Imaging of Acute Scaphoid Trauma

Ashley Groves — 2006-12-16T12:57:32-00:00

Am. J. Roentgenol., Vol. 187, No. 6. (1 December 2006), pp. 1453-1456.

OBJECTIVE. Scaphoid fractures are relatively common. If not treated promptly there may be risk of long-term disability. However, unnecessary wrist immobilization is inconvenient and may hinder professional activities. Therefore, early accurate diagnosis is essential. Currently, the American College of Radiology deems MRI and radiographs as the most appropriate investigations in imaging acute scaphoid trauma. Our objective was to assess scaphoid imaging protocols. MATERIALS AND METHODS. To assess scaphoid imaging protocols, an international survey of imaging practice was performed. Two hundred hospitals worldwide were sent a survey regarding their scaphoid trauma imaging protocols. Only replies from hospitals that had full CT, MRI, and scintigraphy facilities were accepted. RESULTS. Data were obtained from 105 hospitals, of which 23 had fixed protocols. The number of scaphoid radiographic views varied from two to six. Before second-line investigations were initiated, repeat radiographs were usually performed in 76 of the 105 hospitals. In 29 hospitals, other imaging techniques were used without further radiography. The usual second-line investigation was MRI in 31/105, CT in 19/105, and scintigraphy in 14/105. Further protocols included CT or MRI in 10/105, CT or scintigraphy in 6/105, scintigraphy or MRI in 6/105, CT then MRI (if CT was negative) in 1/105, both CT and scintigraphy in 1/105, and scintigraphy then CT (if positive) in 1/105. There was equal preference among MRI, CT, and scintigraphy in 10/105 centers, and clinical examination and radiographs were used alone in 6/105. CONCLUSION. The survey reveals marked inconsistency in the imaging of acute scaphoid injury. Although other factors may have played a role, limited scientific evidence regarding the ideal imaging in acute scaphoid trauma may be the root of this inconsistency. 10.2214/AJR.05.0686

CT pulmonary angiography versus ventilation-perfusion scintigraphy in pregnancy: implications from a UK survey of doctors' knowledge of radiation exposure.

AM Groves — 2006-09-01T11:31:34-00:00

Radiology, Vol. 240, No. 3. (September 2006), pp. 765-770.

PURPOSE: To prospectively investigate the fetal dosimetry knowledge of health care professionals involved in the management of pulmonary embolism. MATERIALS AND METHODS: One hundred sixty-one health care professionals consented to participate in this study, which had ethical board approval. The individuals surveyed were from 14 hospitals (seven university and seven community hospitals) in the United Kingdom, and 68 trainees were included. These health care professionals included 102 radiologists, 13 nuclear physicians, seven dual-accredited radiologist-nuclear medicine physicians, 16 medical physicists, and 23 pulmonologists. The interview included eight questions. Two questions asked which examination-computed tomographic (CT) pulmonary angiography or ventilation-perfusion (V/Q) scintigraphy-gave (a) the larger radiation exposure (effective dose) to an adult and (b) the larger fetal dose. Two questions assessed the magnitude of the dose differences between these two tests. Four questions asked for an estimate of the dose to both adult and fetus from CT pulmonary angiography and scintigraphy. Subgroup analysis was performed by using the Fisher exact test. RESULTS: Of the 161 professionals surveyed, 93 (58%) appreciated correctly that V/Q scintigraphy delivers a higher fetal dose than does CT pulmonary angiography. Three of 161 professionals were able to answer all eight questions correctly. In terms of the knowledge that V/Q scintigraphy has a higher fetal dose than does CT, there was no statistically significant difference in correct answers between specialties (P > .05), between university and community hospitals (P = .13), or between attending physicians and residents (P = .52). CONCLUSION: This survey reveals that there is a lack of knowledge of fetal dosimetry in the imaging of pregnant women suspected of having pulmonary embolism.

The Presence of Lys27 Instead of Asn27 in Human Phospholamban Promotes Sarcoplasmic Reticulum Ca2+-ATPase Superinhibition and Cardiac Remodeling.

Wen Zhao — 2006-02-17T09:38:11-00:00

Circulation (13 February 2006)

BACKGROUND: Phospholamban (PLN) is an inhibitor of the Ca(2+) affinity of sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA2). The amino acid sequence of PLN is highly conserved, and although all species contain asparagine (Asn), human PLN is unique in containing lysine (Lys) at amino acid 27. METHODS AND RESULTS: Human PLN was introduced in the null background. Expression of human PLN, at similar levels to mouse wild-type PLN, resulted in significant decreases in the affinity of SERCA2 for Ca(2+), attributed to unique spatial conformation of this PLN form and increases in its monomeric active unit compared with mouse PLN. The increased inhibition by human PLN was associated with attenuated cardiac contractility in the intact-animal, organ, and cardiomyocyte levels and with depressed calcium kinetics. These inhibitory effects could not be fully reversed even on maximal isoproterenol stimulation. There were no alterations in the expression levels of SERCA2, calsequestrin, ryanodine receptor, and FKBP12, although the sodium/calcium exchanger and the L-type Ca(2+) channel expression levels were upregulated. The depressed function resulted in increased heart/body weight ratios and phosphorylation levels of Akt, p38, and Erk1/2. CONCLUSIONS: Human PLN may play a more inhibitory role than that of other species in Ca(2+) cycling. Expression of human PLN in the mouse is compensated by alterations in Ca(2+)-handling proteins and cardiac remodeling in an effort to normalize cardiac contractility. Thus, the unique amino acid sequence of human PLN may be critical in maintaining a high cardiac reserve, which is of paramount importance in the regulation of human cardiac function.

Merozoite surface protein 1, immune evasion, and vaccines against asexual blood stage malaria.

AA Holder — 2006-02-14T13:24:34-00:00

Parassitologia, Vol. 41, No. 1-3. (September 1999), pp. 409-414.

There is an urgent need for a vaccine against malaria and proteins on the surface of the merozoite are good targets for development as vaccine candidates because they are exposed to antibody. However, it is possible that the parasite has evolved mechanisms to evade a protective immune response to these proteins. Merozoite surface protein 1 (MSP-1) is a candidate for vaccine development and its C-terminal sequence is the target of protective antibody. MSP-1 is cleaved by proteases in two processing steps, the second step releases the bulk of the protein from the surface and goes to completion during successful red blood cell invasion. Antibodies binding to the C-terminus of Plasmodium falciparum MSP-1 can inhibit both the processing and erythrocyte invasion. Other antibodies that bind to either the C-terminal sequence or elsewhere in the molecule are 'blocking' antibodies, which on binding prevent the binding of the inhibitory antibodies. Blocking antibodies are a mechanism of immune evasion, which may be based on antigenic conservation rather than diversity. This mechanism has a number of implications for the study of protective immunity and the development of malaria vaccines, emphasising the need for appropriate functional assays and careful design of the antigen.

Solution structure of an EGF module pair from the Plasmodium falciparum merozoite surface protein 1.

WD Morgan — 2006-02-10T17:37:46-00:00

J Mol Biol, Vol. 289, No. 1. (28 May 1999), pp. 113-122.

The solution structure of the 96-residue C-terminal fragment of the merozoite surface protein 1 (MSP-1) from Plasmodium falciparum has been determined using nuclear magnetic resonance (NMR) spectroscopic measurements on uniformly13C/15N-labelled protein, efficiently expressed in the methylotrophic yeast Komagataella (Pichia) pastoris. The structure has two domains with epidermal growth factor (EGF)-like folds with a novel domain interface for the EGF domain pair interactions, formed from a cluster of hydrophobic residues. This gives the protein a U-shaped overall structure with the N-terminal proteolytic processing site close to the C-terminal glycosyl phosphatidyl inositol (GPI) membrane anchor site, which is consistent with the involvement of a membrane-bound proteinase in the processing of MSP-1 during erythrocyte invasion. This structure, which is the first protozoan EGF example to be determined, contrasts with the elongated structures seen for EGF-module pairs having shared Ca2+-ligation sites at their interface, as found, for example, in fibrillin-1. Recognition surfaces for antibodies that inhibit processing and invasion, and antibodies that block the binding of these inhibitory antibodies, have been mapped on the three-dimensional structure by considering specific MSP-1 mutants.

Inhibitory and blocking monoclonal antibody epitopes on merozoite surface protein 1 of the malaria parasite Plasmodium falciparum.

C Uthaipibull — 2006-02-10T16:37:41-00:00

J Mol Biol, Vol. 307, No. 5. (13 April 2001), pp. 1381-1394.

Merozoite surface protein 1 (MSP-1) is a precursor to major antigens on the surface of Plasmodium spp. merozoites, which are involved in erythrocyte binding and invasion. MSP-1 is initially processed into smaller fragments; and at the time of erythrocyte invasion one of these of 42 kDa (MSP-1(42)) is subjected to a second processing, producing 33 kDa and 19 kDa fragments (MSP-1(33) and MSP-1(19)). Certain MSP-1-specific monoclonal antibodies (mAbs) react with conformational epitopes contained within the two epidermal growth factor domains that comprise MSP-1(19), and are classified as either inhibitory (inhibit processing of MSP-1(42) and erythrocyte invasion), blocking (block the binding and function of the inhibitory mAb), or neutral (neither inhibitory nor blocking). We have mapped the epitopes for inhibitory mAbs 12.8 and 12.10, and blocking mAbs such as 1E1 and 7.5 by using site-directed mutagenesis to change specific amino acid residues in MSP-1(19) and abolish antibody binding, and by using PEPSCAN to measure the reaction of the antibodies with every octapeptide within MSP-1(42). Twenty-six individual amino acid residue changes were made and the effect of each on the binding of mAbs was assessed by Western blotting and BIAcore analysis. Individual changes had either no effect, or reduced, or completely abolished the binding of individual mAbs. No two antibodies had an identical pattern of reactivity with the modified proteins. Using PEPSCAN each mAb reacted with a number of octapeptides, most of which were derived from within the first epidermal growth factor domain, although 1E1 also reacted with peptides spanning the processing site. When the single amino acid changes and the reactive peptides were mapped onto the three-dimensional structure of MSP-1(19), it was apparent that the epitopes for the mAbs could be defined more fully by using a combination of both mutagenesis and PEPSCAN than by either method alone, and differences in the fine specificity of binding for all the different antibodies could be distinguished. The incorporation of several specific amino acid changes enabled the design of proteins that bound inhibitory but not blocking antibodies. These may be suitable for the development of MSP-1-based vaccines against malaria.

Identification of ATF-3, caveolin-1, DLC-1, and NM23-H2 as putative antitumorigenic, progesterone-regulated genes for ovarian cancer cells by gene profiling

Viqar Syed — 2005-01-25T08:16:43-00:00

Oncogene, Vol. aop, No. current. (24 January 2005)

Proapoptotic effects of caspase-1/interleukin-converting enzyme dominate in myocardial ischemia.

FM Syed — 2005-11-03T18:09:07-00:00

Circ Res, Vol. 96, No. 10. (27 May 2005), pp. 1103-1109.

Caspase-1/interleukin-converting enzyme (ICE) is a cysteine protease traditionally considered to have importance as an inflammatory mediator, but not as an apoptotic effector. Because of the dual functions of this caspase, the pathophysiological impact of its reported upregulation in hypertrophy and heart failure is not known. Here, the consequences of increased myocardial expression of procaspase-1 were examined on the normal and ischemically injured heart. In unstressed mouse hearts with a 30-fold increase in procaspase-1 content, unprocessed procaspase-1 was well tolerated, without detectable pathology. Cardiomyocyte processing and activation of caspase-1 and caspase-3 occurred after administration of endotoxin or with transient myocardial ischemia. In post-ischemic hearts, procaspase-1 overexpression was associated with strikingly increased cardiac myocyte apoptosis in the peri- and noninfarct regions and with 50% larger myocardial infarctions. Tissue culture studies revealed that procaspase-1 processing/activation is stimulated by hypoxia, and that caspase-1 acts in synergy with hypoxia to stimulate caspase-3 mediated apoptosis without activating upstream caspases. These data demonstrate that the proapoptotic effects of caspase-1 can significantly impact the myocardial response to ischemia and suggest that conditions in which procaspase-1 in the heart is increased may predispose to apoptotic myocardial injury under conditions of physiological stress.

Elevation of free fatty acids induces inflammation and impairs vascular reactivity in healthy subjects.

D Tripathy — 2005-06-28T14:09:49-00:00

Diabetes, Vol. 52, No. 12. (December 2003), pp. 2882-2887.

To test the possible acute proinflammatory effects of fatty acids, we induced an increase in plasma free fatty acid (FFA) concentrations after a lipid and heparin infusion for 4 h in 10 healthy subjects. We determined the nuclear factor-kappaB (NF-kappaB) binding activity in mononuclear cells (MNCs), the p65 subunit of NF-kappaB, reactive oxygen species (ROS) generation by MNC, and polymorphonuclear leukocytes (PMN). Brachial artery reactivity, using postischemic flow-mediated dilation, was also measured. NF-kappaB binding activity in the MNC nuclear extracts increased to 163 +/- 17% and 144 +/- 14% as compared with basal levels at 2 and 4 h (P < 0.005) and remained elevated (P < 0.05) at 6 h (2 h after cessation of lipid infusion). NF-kappaB p65 subunit protein expression in MNC homogenates also increased at 2, 4, and 6 h (P < 0.05). ROS generation by PMNs increased significantly at 2 and 4 h (P < 0.005), whereas that by MNCs increased at 4 h (P < 0.05). Plasma macrophage migration inhibitory factor increased at 2 (P < 0.05) and 4 h (P < 0.005), respectively, and declined to baseline at 6 h. The postischemic flow-mediated dilation of brachial artery decreased from 6.3 +/- 1.1% at baseline to 4.3 +/- 1.9% and 2.7 +/- 2.1% (P < 0.01) at 2, 4, and 6 h, respectively. We conclude that an increase in FFA concentration induces oxidative stress and has a proinflammatory effect; it also impairs postischemic flow-mediated vasodilation of the brachial artery.

Glucose intake induces an increase in activator protein 1 and early growth response 1 binding activities, in the expression of tissue factor and matrix metalloproteinase in mononuclear cells, and in plasma tissue factor and matrix metalloproteinase concentrations.

A Aljada — 2004-11-22T00:17:30-00:00

Am J Clin Nutr, Vol. 80, No. 1. (July 2004), pp. 51-57.

BACKGROUND: Glucose intake has been shown to cause an increase in intranuclear nuclear factor-kappa B and a decrease in inhibitor kappa B that are consistent with a proinflammatory effect. We investigated the effect of glucose intake on 2 other proinflammatory transcription factors, activator protein 1 (AP-1) and early growth response 1 (Egr-1), and on the genes regulated by them, ie, the genes for matrix metalloproteinases 2 (MMP-2) and 9 (MMP-9) and tissue factor (TF), respectively. OBJECTIVE: The objective of the study was to ascertain whether the intake of 75 g glucose induces an increase in AP-1, Egr-1, and the genes regulated by them. DESIGN: Eight healthy subjects were given 75 g glucose dissolved in 300 mL water to drink. Blood samples were collected before and 1, 2, and 3 h after glucose intake. Four weeks later, the same subjects were given 300 mL water sweetened with saccharine, and blood samples were collected at the same time points. Mononuclear cells (MNCs) were separated, and nuclear fractions were isolated. RESULTS: AP-1 and Egr-1 binding activities were significantly higher 1 and 2 h after glucose intake and then decreased toward the baseline by 3 h. The expression of MMP-2 and TF in MNC homogenates also was significantly higher at 2 and 3 h. Plasma concentrations of MMP-2 were significantly higher at 3 h, whereas those of MMP-9 were significantly higher at 1, 2, and 3 h. In addition, TF was significantly higher at 2 and 3 h. Intake of saccharine-sweetened water had no significant effect on the inflammatory mediators measured in this study. CONCLUSION: Glucose induces proinflammatory changes, including increases in AP-1, Egr-1, MMPs, and TF, the factors that regulate processes that are potentially relevant to atherosclerotic plaque rupture and thrombosis.