97 research outputs found
Client depletion assay comparison of paclitaxel to Hsp90 inhibitors
Many researchers have claimed they have found a successful inhibitor of Hsp90; however, we suspect they are only successful when the inhibitor is used in large quantities. On top of being one of the easiest ways to show an effective inhibitor, researchers are claiming they have found an inhibitor when only meeting as few as two hallmarks. Due to the researchers' inhibitors only meeting two of the criteria, we are trying to show whether these limited expectations are a valid way in identifying Hsp90 inhibitors. We think the client depletion assay test is not specific to Hsp90 inhibitors but instead is a generalized cell response to cell death. At this point in our research, we know a lot about client depletion assays and Hsp90s; however, we do not know if the claims these researchers are making are valid claims because of the amount of Hsp90 inhibitor they are using.Howard Hughes Medical Institute Science Education ProgramBiochemistry and Molecular Biolog
Evaluation of an International Entrepreneur Exchange Program: Impacts, Lessons Learned, and Implications for Agricultural Development
This study evaluated a two-way, visitor exchange project for entrepreneurship development between three African countries and the United States. The study’s purpose was to determine outcomes, understand lessons learned, and derive implications for international agricultural development. Findings of the study confirm visiting African Entrepreneur Fellows (AEFs) developed entrepreneurial knowledge, gained business skills, and acquired positive attitudes toward U.S. business and culture. The majority of AEFs had applied acquired knowledge and skills to improve their businesses and promoted open economic ideals, business ethics, and human rights in their businesses. As a result, AEFs were able to expand their business into new ventures, improve customer services, establish communication networks, and serve their communities. Visitor exchange, entrepreneurship-building programs are effective strategies in contributing to development efforts in developing countries. Paying due attention to the selection and matching of U.S. mentors with the business interests and learning needs of international fellows is necessary to ensure their learning expectations are met. It is important to assign international participants with suitable mentors for longer periods of time to increase the likelihood of receiving more in-depth learning experiences and develop lasting professional relationships to further collaboration. Realization of the potential of entrepreneurship-focused, visitor exchange programs between nations as a strategy for international agricultural development is the major implication of this study
The fate of steroid estrogens: Partitioning during wastewater treatment and onto river sediments
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media B.V.The partitioning of steroid estrogens in wastewater treatment and receiving waters is likely to influence their discharge to, and persistence in, the environment. This study investigated the partitioning behaviour of steroid estrogens in both laboratory and field studies. Partitioning onto activated sludge from laboratory-scale Husmann units was rapid with equilibrium achieved after 1 h. Sorption isotherms and Kd values decreased in the order 17α-ethinyl estradiol > 17α-estradiol > estrone > estriol without a sorption limit being achieved (1/n >1). Samples from a wastewater treatment works indicated no accumulation of steroid estrogens in solids from primary or secondary biological treatment, however, a range of steroid estrogens were identified in sediment samples from the River Thames. This would indicate that partitioning in the environment may play a role in the long-term fate of estrogens, with an indication that they will be recalcitrant in anaerobic conditions.EPSR
A novel a-L-Arabinofuranosidase of Family 43 Glycoside Hydrolase (Ct43Araf ) from Clostridium thermocellum
Articles in International JournalsThe study describes a comparative analysis of biochemical, structural and functional properties of two recombinant
derivatives from Clostridium thermocellum ATCC 27405 belonging to family 43 glycoside hydrolase. The family 43 glycoside
hydrolase encoding a-L-arabinofuranosidase (Ct43Araf) displayed an N-terminal catalytic module CtGH43 (903 bp) followed
by two carbohydrate binding modules CtCBM6A (405 bp) and CtCBM6B (402 bp) towards the C-terminal. Ct43Araf and its
truncated derivative CtGH43 were cloned in pET-vectors, expressed in Escherichia coli and functionally characterized. The
recombinant proteins displayed molecular sizes of 63 kDa (Ct43Araf) and 34 kDa (CtGH43) on SDS-PAGE analysis. Ct43Araf
and CtGH43 showed optimal enzyme activities at pH 5.7 and 5.4 and the optimal temperature for both was 50uC. Ct43Araf
and CtGH43 showed maximum activity with rye arabinoxylan 4.7 Umg21 and 5.0 Umg21, respectively, which increased by
more than 2-fold in presence of Ca2+ and Mg2+ salts. This indicated that the presence of CBMs (CtCBM6A and CtCBM6B) did
not have any effect on the enzyme activity. The thin layer chromatography and high pressure anion exchange
chromatography analysis of Ct43Araf hydrolysed arabinoxylans (rye and wheat) and oat spelt xylan confirmed the release of
L-arabinose. This is the first report of a-L-arabinofuranosidase from C. thermocellum having the capacity to degrade both pnitrophenol-
a-L-arabinofuranoside and p-nitrophenol-a-L-arabinopyranoside. The protein melting curves of Ct43Araf and
CtGH43 demonstrated that CtGH43 and CBMs melt independently. The presence of Ca2+ ions imparted thermal stability to
both the enzymes. The circular dichroism analysis of CtGH43 showed 48% b-sheets, 49% random coils but only 3% a-helices
The Role of NMDA Receptor Antagonists in Nicotine Tolerance, Sensitization, and Physical Dependence: A Preclinical Review
Nicotine, the primary psychoactive component of tobacco products, produces diverse neurophysiological, motivational, and behavioral effects through several brain regions and neurochemical pathways. Various neurotransmitter systems have been explored to understand the mechanisms behind nicotine tolerance, dependence, and withdrawal. Recent evidence suggests that glutamate neurotransmission has an important role in this phenomenon. The aim of the present review is to discuss preclinical findings concerning the role of N-methyl-D-aspartate (NMDA) receptor neurotransmission in mediating the behavioral effects of nicotine, tolerance, sensitization, dependence, and withdrawal. Based on preclinical findings, it is hypothesized that NMDA receptors mediate the common adaptive processes that are involved in the development, maintenance, and expression of nicotine addiction. Modulation of glutamatergic neurotransmission with NMDA receptor antagonists may prove to be useful in alleviating the symptoms of nicotine abstinence and facilitate tobacco-smoking cessation
The Role of NMDA Receptor Antagonists in Nicotine Tolerance, Sensitization, and Physical Dependence: A Preclinical Review
Nicotine, the primary psychoactive component of tobacco products, produces diverse neurophysiological, motivational, and behavioral effects through several brain regions and neurochemical pathways. Various neurotransmitter systems have been explored to understand the mechanisms behind nicotine tolerance, dependence, and withdrawal. Recent evidence suggests that glutamate neurotransmission has an important role in this phenomenon. The aim of the present review is to discuss preclinical findings concerning the role of N-methyl-D-aspartate (NMDA) receptor neurotransmission in mediating the behavioral effects of nicotine, tolerance, sensitization, dependence, and withdrawal. Based on preclinical findings, it is hypothesized that NMDA receptors mediate the common adaptive processes that are involved in the development, maintenance, and expression of nicotine addiction. Modulation of glutamatergic neurotransmission with NMDA receptor antagonists may prove to be useful in alleviating the symptoms of nicotine abstinence and facilitate tobacco-smoking cessation
Two Distinct Modes of Hypoosmotic Medium-Induced Release of Excitatory Amino Acids and Taurine in the Rat Brain In Vivo
A variety of physiological and pathological factors induce cellular swelling in the brain. Changes in cell volume activate several types of ion channels, which mediate the release of inorganic and organic osmolytes and allow for compensatory cell volume decrease. Volume-regulated anion channels (VRAC) are thought to be responsible for the release of some of organic osmolytes, including the excitatory neurotransmitters glutamate and aspartate. In the present study, we compared the in vivo properties of the swelling-activated release of glutamate, aspartate, and another major brain osmolyte taurine. Cell swelling was induced by perfusion of hypoosmotic (low [NaCl]) medium via a microdialysis probe placed in the rat cortex. The hypoosmotic medium produced several-fold increases in the extracellular levels of glutamate, aspartate and taurine. However, the release of the excitatory amino acids differed from the release of taurine in several respects including: (i) kinetic properties, (ii) sensitivity to isoosmotic changes in [NaCl], and (iii) sensitivity to hydrogen peroxide, which is known to modulate VRAC. Consistent with the involvement of VRAC, hypoosmotic medium-induced release of the excitatory amino acids was inhibited by the anion channel blocker DNDS, but not by the glutamate transporter inhibitor TBOA or Cd2+, which inhibits exocytosis. In order to elucidate the mechanisms contributing to taurine release, we studied its release properties in cultured astrocytes and cortical synaptosomes. Similarities between the results obtained in vivo and in synaptosomes suggest that the swelling-activated release of taurine in vivo may be of neuronal origin. Taken together, our findings indicate that different transport mechanisms and/or distinct cellular sources mediate hypoosmotic medium-induced release of the excitatory amino acids and taurine in vivo
An Animal Model of Emotional Blunting in Schizophrenia
Schizophrenia is often associated with emotional blunting—the diminished ability to respond to emotionally salient stimuli—particularly those stimuli representative of negative emotional states, such as fear. This disturbance may stem from dysfunction of the amygdala, a brain region involved in fear processing. The present article describes a novel animal model of emotional blunting in schizophrenia. This model involves interfering with normal fear processing (classical conditioning) in rats by means of acute ketamine administration. We confirm, in a series of experiments comprised of cFos staining, behavioral analysis and neurochemical determinations, that ketamine interferes with the behavioral expression of fear and with normal fear processing in the amygdala and related brain regions. We further show that the atypical antipsychotic drug clozapine, but not the typical antipsychotic haloperidol nor an experimental glutamate receptor 2/3 agonist, inhibits ketamine's effects and retains normal fear processing in the amygdala at a neurochemical level, despite the observation that fear-related behavior is still inhibited due to ketamine administration. Our results suggest that the relative resistance of emotional blunting to drug treatment may be partially due to an inability of conventional therapies to target the multiple anatomical and functional brain systems involved in emotional processing. A conceptual model reconciling our findings in terms of neurochemistry and behavior is postulated and discussed
Outcomes of obstructed abdominal wall hernia: results from the UK national small bowel obstruction audit
Background:
Abdominal wall hernia is a common surgical condition. Patients may present in an emergency with bowel obstruction, incarceration or strangulation. Small bowel obstruction (SBO) is a serious surgical condition associated with significant morbidity. The aim of this study was to describe current management and outcomes of patients with obstructed hernia in the UK as identified in the National Audit of Small Bowel Obstruction (NASBO).
Methods:
NASBO collated data on adults treated for SBO at 131 UK hospitals between January and March 2017. Those with obstruction due to abdominal wall hernia were included in this study. Demographics, co-morbidity, imaging, operative treatment, and in-hospital outcomes were recorded. Modelling for factors associated with mortality and complications was undertaken using Cox proportional hazards and multivariable regression modelling.
Results:
NASBO included 2341 patients, of whom 415 (17·7 per cent) had SBO due to hernia. Surgery was performed in 312 (75·2 per cent) of the 415 patients; small bowel resection was required in 198 (63·5 per cent) of these operations. Non-operative management was reported in 35 (54 per cent) of 65 patients with a parastomal hernia and in 34 (32·1 per cent) of 106 patients with an incisional hernia. The in-hospital mortality rate was 9·4 per cent (39 of 415), and was highest in patients with a groin hernia (11·1 per cent, 17 of 153). Complications were common, including lower respiratory tract infection in 16·3 per cent of patients with a groin hernia. Increased age was associated with an increased risk of death (hazard ratio 1·05, 95 per cent c.i. 1·01 to 1·10; P = 0·009) and complications (odds ratio 1·05, 95 per cent c.i. 1·02 to 1·09; P = 0·001).
Conclusion:
NASBO has highlighted poor outcomes for patients with SBO due to hernia, highlighting the need for quality improvement initiatives in this group
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