Effect of improved diabetes control on the expression of lipoprotein lipase in human adipose tissue.

Patients with diabetes commonly manifest hypertriglyceridemia along with decreased adipose tissue lipoprotein lipase (LPL) activity, and improved diabetes control tends to reverse these abnormalities. To better understand the mechanism of regulation of LPL in diabetes, 11 diabetic patients (3 type I, 8 type II) were brought under improved glycemic control, and adipose tissue LPL gene expression was assessed by performing paired fat biopsies. Six of the 11 patients attained improved control with insulin, with a decrease in glycohemoglobin (glyc Hgb) from 13.8 +/- 0.9 to 10.4 +/- 0.6%; 5 patients attained improved control with glyburide (glyc Hgb fell from 14.2 +/- 2.4 to 8.8 +/- 0.6%), and together they demonstrated a lowering of serum triglycerides and total cholesterol. No changes were observed in HDL cholesterol. Improved diabetes control resulted in a significant increase in LPL activity in both the heparin-releasable (HR) and extractable (EXT) fractions of adipose tissue, as well as in LPL immunoreactive mass. The change in LPL activity with improved control was variable, and showed a positive correlation with the HDL levels prior to treatment (r = 0.74, P less than 0.02). When adipose tissue was pulse-labeled with [35S]methionine, there was an increase in isotope incorporation into LPL after treatment, indicating an increase in LPL synthetic rate. However, improved diabetes control resulted in no significant change in LPL mRNA levels. Thus, improved glycemic control resulted in an increase in LPL activity which correlated with each patient's basal high density lipoprotein. This increase in LPL activity was accompanied by an increase in LPL immunoreactive mass, and an increase in LPL synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Design,synthesis, and biological evaluation of selective and potent Carbazole-based butyrylcholinesterase inhibitors

Alzheimer’s disease (AD) is the most common form of dementia. Inhibition of BChE might be a useful therapeutic target for AD. A new series of Carbazole-Benzyl Pyridine derivatives were designed synthesized and evaluated as butyrylcholinesterase (BChE) inhibitors. In vitro assay revealed that all of the derivatives had selective and potent anti- BChE activities. 3-((9H-Carbazol-9-yl)methyl)-1-(4-chlorobenzyl)pyridin-1-ium chloride (compound 8f) had the most potent anti-BChE activity (IC₅₀ value?=?0.073?μM), the highest BChE selectivity and mixed-type inhibition. Docking study revealed that 8f interacted with the peripheral site, the choline binding site, catalytic site and the acyl pocket of BChE. Physicochemical properties were accurate to Lipinski's rule. In addition, compound 8f demonstrated neuroprotective activity at 10?µM. This compound could also inhibit AChE-induced and self-induced Aβ peptide aggregation at concentration of 100?µM and 10?µM respectively. The in-vivo study showed that compound 8f in 10?mg/kg increased the time spent in target quadrant in the probe day and decreased mean training period scape latency in rats. All results suggest that new sets of potent selective inhibitors of BChE have a therapeutic potential for the treatment of AD.     

Identification of antimony resistance markers in Leishmania tropica field isolates through a cDNA-AFLP approach

Pentavalent antimonial compounds have been the first line therapy for leishmaniasis; unfortunately the rate of treatment failure of anthroponotic cutaneous leishmaniasis (ACL) is increasing due to emerging of drug resistance. Elucidation of the molecular mechanisms operating in antimony resistance is critical for development of new strategies for treatment. Here, we used a cDNA-AFLP approach to identify gene(s) which are differentially expressed in resistant and sensitive Leishmania tropica field isolates. We identified five genes, aquaglyceroporin (AQP1) acts in drug uptake, ATP-binding cassette (ABC) transporter (MRPA) involved in sequestration of drug, phosphoglycerate kinase (PGK) implicated in glycolysis metabolism, mitogen activated protein kinase (MAPK) and protein tyrosine phosphatase (PTP) responsible for phosphorylation pathway. The results were confirmed using real time RT-PCR which revealed an upregulation of MRPA, PTP and PGK genes and downregulation of AQP1 and MAPK genes in resistant isolate. To our knowledge, this is the first report of identification of PTP and PGK genes potentially implicated in resistance to antimonials. Our findings support the idea that distinct biomolecules might be involved in antimony resistance in L. tropica field isolates.     

Efficiency of Plasmocin™ on various mammalian cell lines infected by mollicutes in comparison with commonly used antibiotics in cell culture: a local experience

Mycoplasma contamination is a deleterious event for cell culture laboratories. Plasmocin™ is used to prevent and eradicate mycoplasma infections from cell. In this study, 80 different mammalian cell lines from various sources; human, monkey, mice, hamster and rat were used to study and evaluate plasmocin™ efficiency and compare it to commonly used antibiotics such as BM-cyclin, ciprofloxacin and mycoplasma removal agent (MRA). It was shown that mycoplasma infections were eradicated by plasmocin™, BM-cyclin, ciprofloxacin and MRA in 65%, 66.25%, 20%, and 31.25%, respectively, of infected cell cultures. However, re-infection with mycoplasmas after the period of 4 months occurred in 10–80% of the studied cell lines. Cell cytotoxicity and culture death was observed in 25, 17.5 and 10% of the treated cells, for plasmocin™, BM-cyclin and MRA, respectively. In this study, Plasmocin™ showed strong ability to eradicate mollicutes from our cell lines with minimal percentage of regrowth. However, due to its high cell cytotoxicity it should be used with caution especially when dealing with expensive or hard-to-obtain cell lines. Amongst the antibiotics tested, BM-cyclin was shown to remove mycoplasma with the highest efficiency.     

Advantages and Limitations of Androgen Receptor-Based Methods for Detecting Anabolic Androgenic Steroid Abuse as Performance Enhancing Drugs

Testosterone (T) and related androgens are performance enhancing drugs (PEDs) abused by some athletes to gain competitive advantage. To monitor unauthorized androgen abuse, doping control programs use mass spectrometry (MS) to detect androgens, synthetic anabolic-androgenic steroids (AASs) and their metabolites in an athlete’s urine. AASs of unknown composition will not be detected by these procedures. Since AASs achieve their anabolic effects by activating the Androgen Receptor (AR), cell-based bioassays that measure the effect of a urine sample on AR activity are under investigation as complementary, pan-androgen detection methods. We evaluated an AR BioAssay as a monitor for androgen activity in urine pre-treated with glucuronidase, which releases T from the inactive T-glucuronide that predominates in urine. AR BioAssay activity levels were expressed as ‘T-equivalent’ concentrations by comparison to a T dose response curve. The T-equivalent concentrations of androgens in the urine of hypogonadal participants supplemented with T (in whom all androgenic activity should arise from T) were quantitatively identical to the T measurements conducted by MS at the UCLA Olympic Analytical Laboratory (0.96 ± 0.22). All 17 AASs studied were active in the AR BioAssay; other steroids were inactive. 12 metabolites of 10 commonly abused AASs, which are used for MS monitoring of AAS doping because of their prolonged presence in urine, had reduced or no AR BioAssay activity. Thus, the AR BioAssay can accurately and inexpensively monitor T, but its ability to monitor urinary AASs will be limited to a period immediately following doping in which the active AASs remain intact.     

Using tuberous sclerosis complex to understand the impact of MTORC1 signaling on mitochondrial dynamics and mitophagy in neurons

Constitutive activation of the MTOR pathway is a key feature of defects in the tuberous sclerosis complex and other genetic neurodevelopmental diseases, collectively referred to as MTORopathies. MTORC1 hyperactivity promotes anabolic cell functions such as protein synthesis, yet at the same time catabolic processes such as macroautophagy/autophagy are suppressed. Mitochondria are major substrates of autophagy; however, their role in MTORopathies remains largely undefined. Here, we review our recent study showing that several aspects of mitochondrial function, dynamics and turnover are critically impaired in neuronal models of TSC. We discuss the relevance of these findings to neurological manifestations associated with TSC and speculate on autophagy as a novel treatment target for MTORopathies.     

Dorsal hippocampal dopamine receptors are involved in mediating ethanol state-dependent memory

In the present study, the effects of bilateral injections of dopaminergic agents into the hippocampal CA1 regions (intra-CA1) on ethanol (EtOH) state-dependent memory were examined in mice. A single-trial step-down passive avoidance task was used for the assessment of memory retention in adult male NMRI mice. Pre-training intra-peritoneal (i.p.) administration of EtOH (0.25, 0.5 and 1 g/kg) dose dependently induced impairment of memory retention. Pre-test administration of EtOH (0.5 g/kg)-induced state-dependent retrieval of the memory acquired under pre-training EtOH (0.5 g/kg) influence. Intra-CA1 administration of the dopamine D(1) receptor agonist, SKF 38393 (0.5, 1 and 2 g/mouse) or the dopamine D(2) receptor agonist, quinpirole (0.25, 0.5 and 1 microg/mouse) alone cannot affect memory retention. While, pre-test intra-CA1 injection of SKF 38393 (2 microg/mouse, intra-CA1) or quinpirole (0.25, 0.5 and 1 microg/mouse, intra-CA1) improved pre-training EtOH (0.5 g/kg)-induced retrieval impairment. Moreover, pre-test administration of SKF 38393 (0.5, 1 and 2 microg/mouse, intra-CA1) or quinpirole (0.5 and 1 microg/mouse, intra-CA1) with an ineffective dose of EtOH (0.25 g/kg) significantly restored the retrieval and induced EtOH state-dependent memory. Furthermore, pre-training injection of the dopamine D(1) receptor antagonist, SCH 23390 (4 microg/mouse), but not the dopamine D(2) receptor antagonist, sulpiride, into the CA1 regions suppressed the learning of a single-trial passive avoidance task. Pre-test intra-CA1 injection of SCH 23390 (2 and 4 microg/mouse, intra-CA1) or sulpiride (2.5 and 5 microg/mouse, intra-CA1) 5 min before the administration of EtOH (0.5 g/kg, i.p.) dose dependently inhibited EtOH state-dependent memory. These findings implicate the involvement of a dorsal hippocampal dopaminergic mechanism in EtOH state-dependent memory and also it can be concluded that there may be a cross-state dependency between EtOH and dopamine.     

Atrial Fibrillation and Colonic Neoplasia in African Americans

Background

Colorectal cancer (CRC) and atrial fibrillation/flutter (AF) share several risk factors including increasing age and obesity. However, the association between CRC and AF has not been thoroughly examined, especially in African Americans. In this study we aimed to assess the prevalence of AF and its risk factors in colorectal neoplasia in an African American.

Methods

We reviewed records of 527 African American patients diagnosed with CRC and 1008 patients diagnosed with benign colonic lesions at Howard University Hospital from January 2000 to December 2012. A control group of 731 hospitalized patients without any cancer or colonic lesion were randomly selected from the same time and age range, excluding patients who had diagnosis of both CRC and/or adenoma. The presence or absence of AF was based upon ICD-9 code documentation. The prevalence of AF in these three groups was compared by multivariate logistic regression.

Results

The prevalence of AF was highest among CRC patients (10%) followed by adenoma patients (7.2%) then the control group (5.4%, P for trend = 0.002). In the three groups of participants, older age (P<0.008) and heart failure (P<0.001) were significantly associated with higher risk of AF. After adjusting for these risk factors, CRC (OR: 1.4(95%CI):0.9–2.2, P = 0.2) and adenoma (OR: 1.1(95%CI):0.7–1.6, P = 0.7) were not significantly associated AF compared to control group.

Conclusions

AF is highly prevalent among CRC patients; 1 in 10 patients had AF in our study. The predictors of AF in CRC was similar to that in adenoma and other patients after adjustment for potential confounders suggesting that the increased AF risk in CRC is explained by higher prevalence of AF risk factors.     

Controlled microchannelling in dense collagen scaffolds by soluble phosphate glass fibers

A problem with tissue engineering scaffolds is maintaining seeded cell viability and function due to limitations of oxygen and nutrient transfer. An approach to maintain suitable oxygen concentrations throughout the scaffold would be to controllably incorporate microchannelling within these scaffolds. This study investigated the incorporation of unidirectionally aligned soluble phosphate based glass fibers (PGF) into dense collagen scaffolds. PGF are degradable, and their degradation can be controlled through their chemistry and dimensions. Plastic compression was used to produce composite scaffolds at three different weight percentage while maintaining greater than 80% resident cell viability. PGF-collagen scaffold composition was quantified through thermogravimetric analysis as well as being morphologically and mechanically characterized. PGF degradation was measured through ion chromatography, and channel formation was verified with ultrasound imaging and SEM. The free movement of coated microbubble agents confirmed the channels to be continuous in nature and of 30-40 microm diameter. These microchannels in dense native collagen matrices could play an important role in hypoxia/perfusion limitations and also in the transportation of nutrients and potentially forming blood vessels through dense implants.