Melatonin Improves Memory Deficits in Rats with Cerebral Hypoperfusion,Possibly, Through Decreasing the Expression of Small-Conductance Ca2+-Activated K+ Channels

Neurochemical Research - This study investigated the expression pattern, regulation of expression, and the role of hippocampal small-conductance Ca2+-activated K+ (SK) channels in memory deficits...     

Virulence cost in Plasmopara halstedii (sunflower downy mildew)

Virulence cost (trade-off between virulence and aggressiveness) was studied in seven Plasmopara halstedii (sunflower downy mildew) isolates of races 100, 300, 304, 314, 710, 704 and 714. The seven isolates were divided, according to their virulence and aggressiveness, into two main groups as more aggressive isolates of the 100 and 3xx races that do not overcome the sunflower differential host D3, and less aggressive isolates of 7xx races that can overcome D3. Consequently, the 100 and 3xx avirulent races had a virulence cost measured by differences in aggressiveness (from 58.3 to 78.2%) compared to 7xx virulent races carrying unnecessary virulence gene.     

Male,Mobile, and Moneyed: Loss to Follow-Up vs. Transfer of Care in an Urban African Antiretroviral Treatment Clinic

Objectives

The purpose of this study was to analyze characteristics, reasons for transferring, and reasons for discontinuing care among patients defined as lost to follow-up (LTFU) from an antiretroviral therapy (ART) clinic in Nairobi, Kenya.

Design

The study used a prospective cohort of patients who participated in a randomized, controlled ART adherence trial between 2006 and 2008.

Methods

Participants were followed from pre-ART clinic enrollment to 18 months after ART initiation, and were defined as LTFU if they failed to return to clinic 4 weeks after their last scheduled visit. Reasons for loss were captured through phone call or home visit. Characteristics of LTFU who transferred care and LTFU who did not transfer were compared to those who remained in clinic using log-binomial regression to estimate risk ratios.

Results

Of 393 enrolled participants, total attrition was 83 (21%), of whom 75 (90%) were successfully traced. Thirty-seven (49%) were alive at tracing and 22 (59%) of these reported having transferred their antiretroviral care. In the final model, transfers were more likely to have salaried employment [Risk Ratio (RR), 2.7; 95% confidence interval (CI), 1.2-6.1; p=0.020)] and pay a higher monthly rent (RR, 5.8; 95% CI, 1.3-25.0; p=0.018) compared to those retained in clinic. LTFU who did not transfer care were three times as likely to be men (RR, 3.1; 95% CI, 1.1-8.1; p=0.028) and nearly 4 times as likely to have a primary education or less (RR, 3.8; 95% CI, 1.3-10.6; p=0.013). Overall, the most common reason for LTFU was moving residence, predominantly due to job loss or change in employment.

Conclusion

A broad definition of LTFU may include those who have transferred their antiretroviral care and thereby overestimate negative effects on ART continuation. Interventions targeting men and considering mobility due to employment may improve retention in urban African ART clinics.

Clinical Trials

The study’s ClinicalTrials.gov identifier is NCT00273780.     

Residual Disease and HPV Persistence after Cryotherapy for Cervical Intraepithelial Neoplasia Grade 2/3 in HIV-Positive Women in Kenya

Objective

To assess residual cervical intraepithelial neoplasia (CIN) 2/3 disease and clearance of high-risk (hr) human papillomavirus (HPV) infections at 6 months after cryotherapy among HIV-positive women.

Design

Follow-up study.

Methods

79 HIV-positive women received cryotherapy for CIN2/3 in Nairobi, Kenya, and underwent conventional cytology 6 months later. Biopsies were performed on high grade cytological lesions and hrHPV was assessed before (cervical cells and biopsy) and after cryotherapy (cells).

Results

At 6 months after cryotherapy CIN2/3 had been eliminated in 61 women (77.2%; 95% Confidence Interval, (CI): 66.4–85.9). 18 women (22.8%) had residual CIN2/3, and all these women had hrHPV at baseline. CD4 count and duration of combination antiretroviral therapy (cART) were not associated with residual CIN2/3. CIN3 instead of CIN2 was the only significant risk factor for residual disease (odds ratio, OR vs CIN2 = 4.3; 95% CI: 1.2–15.0) among hrHPV-positive women after adjustment for age and HPV16 infection. Persistence of hrHPV types previously detected in biopsies was found in 77.5% of women and was associated with residual CIN2/3 (OR = 8.1, 95% CI: 0.9–70). The sensitivity, specificity, and negative predictive value of hrHPV test in detecting residual CIN2/3 were 0.94, 0.36, and 0.96 respectively.

Conclusions

Nearly one quarter of HIV-positive women had residual CIN2/3 disease at 6 months after cryotherapy, and the majority had persistent hrHPV. CD4 count and cART use were not associated with residual disease or hrHPV persistence. The value of hrHPV testing in the detection of residual CIN2/3 was hampered by a low specificity.     

DLBench: a comprehensive experimental evaluation of deep learning frameworks

Cluster Computing - Deep Learning (DL) has achieved remarkable progress over the last decade on various tasks such as image recognition, speech recognition, and natural language processing. In...     

Hormonal treatment of the bark of rubber trees (Hevea brasiliensis) increases latex yield through latex dilution in relation with the differential expression of two aquaporin genes

Natural rubber is synthesized in laticifers in the inner liber of the rubber tree (Hevea brasiliensis). Upon bark tapping, the latex is expelled due to liber turgor pressure. The mature laticifers are devoid of plasmodesmata; therefore a corresponding decrease in the total latex solid content is likely to occur due to water influx inside the laticifers. Auxins and ethylene used as efficient yield stimulants in mature untapped rubber trees, but, bark treatments with abscisic acid (ABA) and salicylic acid (SA) could also induce a transient increase latex yield. We recently reported that there are three aquaporin genes, HbPIP2;1, HbTIP1;1 and HbPIP1;1, that are regulated differentially after ethylene bark treatment. HbPIP2;1 was up-regulated in both the laticifers and the inner liber tissues, whereas HbTIP1;1 was up-regulated in the latex cells, but very markedly down-regulated in the inner liber tissues. Conversely, HbPIP1;1 was down-regulated in both tissues. In the present study, HbPIP2;1 and HbTIP1;1 showed a similar expression in response to auxin, ABA and SA, as seen in ethylene stimulation, while HbPIP1;1 was slightly regulated by auxin, but neither by ABA nor SA. The analysis of the HbPIP1;1 promoter region indicated the presence of only ethylene and auxin responsive elements. In addition, the poor efficiency of this HbPIP1;1 in increasing plasmalemma water conductance was confirmed in Xenopus oocytes. Thus, an increase in latex yield in response to all of these hormones was proposed to be the major function of aquaporins, HbPIP2;1 and HbTIP1;1. This study emphasized that the circulation of water between the laticifers and their surrounding tissues that result in latex dilution, as well as the probable maintenance of the liber tissues turgor pressure, favor the prolongation of latex flow.     

Acute exposure to Catha edulis depresses contractility and induces myocardial infarction in spontaneously contracting,isolated rabbit’s heart

Khat chewing is a recreational habit known to pose major socio-economic and medical problems in countries of Southern Arabia and the Horn of Africa. Among other adverse health effects, khat chewing has been associated with an increased risk of myocardial infarction (MI) in heavy consumers. This study was carried out to examine the direct effects of Catha edulis extract on contractility of spontaneously contracting, isolated rabbit heart and to investigate its mechanism of action. Isolated six rabbit’s hearts attached to a Langendorff apparatus were perfused with extract at a constant flow rate and continuously bubbled with a 95% O₂/5% CO₂ gas mixture. Each heart served as its own control, as responses were recorded before and after administration of C. edulis extract. Varying concentrations of extract (50, 100 and 250 mg/ml) were loaded in the perfusate, their effects recorded and effluent fluid collected for assay of cardiac enzymes. Histological examination of the cardiac tissue was performed at the end of perfusion with 250 mg/ml extract. This study revealed that acute exposure to C. edulis extract exerted negative inotropic and chronotropic effects on isolated hearts. The extract also had a vasoconstrictor effect on coronary vessels, independent of α₁ adrenergic receptor stimulation. Histological examination of hearts perfused with 250 mg/ml C. edulis extract revealed the presence of histological changes unique to myocardial infarction, a finding consistent with observed increased levels of cardiac enzymes in perfusates. Thus, we have demonstrated experimentally a direct cardiac depressant- and MI inducing effects of C. edulis extract. These results are consistent with the earlier reported deleterious effects of khat on cardiovascular function among khat chewers.     

The uptake and degradation of matrix-bound lipoproteins by macrophages require an intact actin Cytoskeleton, Rho family GTPases, and myosin ATPase activity

A key cellular event in atherogenesis is the interaction of macrophages with lipoproteins in the subendothelium. In vivo, these lipoproteins are bound to matrix and often aggregated, yet most cell-culture experiments explore these events using soluble monomeric lipoproteins. We hypothesized that the internalization and degradation of matrix-retained and aggregated low density lipoprotein (LDL) by macrophages may involve the actin-myosin cytoskeleton in a manner that distinguishes this process from the endocytosis of soluble LDL. To explore these ideas, we plated macrophages on sphingomyelinase-aggregated LDL bound to smooth muscle cell-derived matrix in the presence of lipoprotein lipase. The macrophages internalized and degraded the LDL, which was mediated partially by the LDL receptor-related protein. Cytochalasin D and latrunculin A, which block actin polymerization, markedly inhibited the uptake and degradation of matrix-retained LDL but not soluble LDL. Inhibition of Rho family GTPases by Clostridium difficile toxin B blocked the degradation of matrix-retained and aggregated LDL by >90% without any inhibition of soluble LDL degradation. However, specific inhibition of Rho had no effect, suggesting the importance of Rac1 and Cdc42. Degradation of matrix-retained, but not soluble, LDL was also blocked by inhibitors of tyrosine kinase, phosphatidylinositol 3-kinase, and myosin ATPase. These findings define fundamental cytoskeletal pathways that may be involved in macrophage foam cell formation in vivo but have been missed by the use of previous cell culture models.     

Complementary medicine for prostate cancer: effects of soy and fat consumption

Complementary medicine has become an increasing area of interest for patients and researchers around the world. The utilization of some of these therapies by many individuals makes it imperative to understand if they have a role in cancer or other disease treatment. Soy products have generated a large interest because a variety of laboratory and epidemiologic research suggests these items may play a role in the prevention of prostate cancer. Clinical trials are addressing this issue and whether or not these products could also improve prognosis of prostate cancer. Additionally, other soy-based capsules (ipriflavone) have received some research, but the largest clinical study to date does not support the use of these supplements to reduce hot flashes and/or osteoporosis risk. Dietary fat reduction to prevent prostate cancer is supported by numerous case-control studies over the past 25 years. However, recent prospective studies suggest that fat reduction may not play a strong role in prevention of prostate carcinoma. Soy products and fat reduction may have a symbiotic relationship. Any healthy lifestyle or dietary change should be encouraged, because it may reduce the risk of cardiovascular disease, which is still the number one cause of mortality.     

Tumor-suppressive maspin regulates cell response to oxidative stress by direct interaction with glutathione S-transferase

Maspin, a novel serine protease inhibitor, suppresses tumor progression in several cancer models, including an in vivo model for prostate cancer bone metastasis. However, the molecular mechanism of maspin remains illusive, primarily because its molecular targets are unknown. To this end, we used a full-length maspin cDNA bait to screen against both a primary prostate tumor cDNA prey library and a HeLa cDNA prey library by the yeast two-hybrid method. We found that heat shock protein 90, glutathione S-transferase (GST), and heat shock protein 70 interacted with maspin with the highest frequencies. We confirmed the maspin/GST interaction using purified proteins, human epithelial cell lines, and human prostate tissues. A maspin variant that has a point mutation of Arg(340) to Ala (Mas(R340A)) showed a significantly decreased affinity for GST. Although purified maspin had no effect on the activity of purified GST in vitro, intracellular interaction between endogenous maspin and GST correlated with an elevated total GST activity in both MDA-MB-435- and DU145-derived stably transfected cells. Consistently, tumor cells treated with purified wild type maspin, but not Mas(R340A), enhanced cellular GST activity. Maspin expression in cancer cell lines also correlated with decreased basal levels of reactive oxygen species (ROS). Furthermore, H(2)O(2) treatment not only induced GST expression but also increased intracellular maspin/GST interaction, which was inversely correlated with the level of ROS generation. Conversely, maspin knockdown by small interfering RNA increased the basal, as well as H(2)O(2)-induced, ROS generation. Furthermore, the maspin effect on ROS generation was completely abolished by a GST inhibitor, indicating an essential role of GST in maspin-mediated cellular response to oxidative stress. Consistently, oxidative stress-induced vascular endothelial growth factor A expression was significantly inhibited in maspin-expressing cells. Together, our data suggest a new mechanism by which maspin, through its direct interaction with GST, may inhibit oxidative stress-induced ROS generation and vascular endothelial growth factor A induction, thus preventing further adverse effects on tumor genetics and stromal reactivity.