Efflux of Glutathione and Glutathione Complexes from Human Erythrocytes in Response to Inorganic Arsenic Exposure

The objective of the present study was to investigate if arsenic exposure results in glutathione efflux from human erythrocytes. Arsenite significantly depleted intracellular nonprotein thiol level in a time- and concentration-dependent manner. The intracellular nonprotein thiol level was decreased to 0.767?±?0.0017???mol/ml erythrocyte following exposure to 10?mM of arsenite for 4?h. Extracellular nonprotein thiol level was increased concomitantly with the intracellular decrease and reached to 0.481?±?0.0005???mol/ml erythrocyte in 4?h. In parallel with the change in extracellular nonprotein thiol levels, significant increases in extracellular glutathione levels were detected. Extracellular glutathione levels reached to 0.122?±?0.0013, 0.226?±?0.003, and 0.274?±?0.004???mol/ml erythrocyte with 1, 5, and 10?mM of arsenite, respectively. Dimercaptosuccinic acid treatment of supernatants significantly increased the glutathione levels measured in the extracellular media. Utilization of MK571 and verapamil, multidrug resistance-associated protein 1 and Pgp inhibitors, decreased the rate of glutathione efflux from erythrocytes suggesting a role for these membrane transporters in the process. The results of the present study indicate that human erythrocytes efflux glutathione in reduced free form and in conjugated form or forms that can be recovered with dimercaptosuccinic acid when exposed to arsenite.     

Insulin‐regulated expression of adiponectin receptors in muscle and fat cells

Adp (adiponectin), an adipocyte‐secreted hormone, exerts its effect via its specific receptors, AdipoR1 and AdipoR2 (adiponectin receptors 1 and 2), on insulin‐sensitive cells in muscle, liver and adipose tissues, and plays an important role in lipid and glucose metabolisms. The study has investigated the effect of insulin on AdipoRs expression in muscle and fat cells. Differentiated fat [3T3‐L1 (mouse adipocytes)], L6 (skeletal muscle) and vascular smooth muscle (PAC1) cells were serum starved and exposed to 100 nM insulin for 1–24 h. AdipoR1 and AdipoR2 mRNAs expression was monitored by real‐time PCR. The results demonstrate that insulin down‐regulates both AdipoR1 and AdipoR2 mRNAs levels in a biphasic manner in L6 and PAC1 cells. Insulin had little or no effect in the regulation of AdipoR1 expression in 3T3‐L1 cells, but significantly up‐regulated AdipoR2 mRNA level in a biphasic manner. The fact that insulin differentially regulates the expression of AdipoR1 and AdipoR2 in muscle and fat cells suggests this is also dependent on the availability of the endogenous ligand, such as Adp for AdipoR1 and AdipoR2 in fat cells. The effects of globular Adp were also tested on insulin‐regulated expression of AdipoRs in L6 cells, and found to up‐regulate and counter insulin‐mediated suppression of AdipoRs expression in L6 cells.     

Synthesis, spectroscopy, and biological properties of vanadium(IV)-hydrazide complexes

The synthesis, spectroscopic, enzyme-inhibition, and free-radical-scavenging properties of a series of vanadium(IV) complexes, compounds 1-10, were investigated. These complexes exhibit a dimeric structure with hydrazide ligands coordinated in a bidentate fashion. All complexes are stable in the solid state, but exhibit varying degrees of stability in solution. In coordinating solvent such as DMSO, stepwise binding of two solvent molecules at the 6th positions trans to the V double bond O bond of the dimeric unit is observed. The dimeric compounds are converted to monomeric species in which both solvent molecules and the hydrazide ligands are coordinated to the V(IV) center. The free hydrazide ligands 11-20 were inactive against alpha-glucosidase, but the V(IV) complexes showed varying degrees of inhibition, depending on the type of ligand. The DPPH-radical-scavenging activities of 1-20 were determined, which indicated that steric and/or electronic effects responsible for changes in geometry play important roles in terms of antioxidant potential.     

Evaluation of chalcones as inhibitors of glutathione S‐transferase

Glutathione S‐transferases (GSTs) are the superfamily of multifunctional detoxification isoenzymes and play an important role in cellular signaling. In the present study, potential inhibition effects of chalcones were tested against human GST. For this purpose, GST was purified from human erythrocytes with 5.381 EU?mg^?1 specific activity and 51.95% yield using a GSH–agarose affinity chromatographic method. The effects of chalcones on in vitro GST activity were tested at various concentrations. K_i constants of chalcones were found in the range of 7.76–41.93 μM. According to the results, 4‐fluorochalcone showed a better inhibitory effect compared with the other compounds. The inhibition mechanisms of 2'‐hydroxy‐4‐methoxychalcone and 4‐methoxychalcone were noncompetitive, whereas the inhibition mechanisms of 4'‐ hydroxychalcone, 4‐ fluorochalcone, and 4,4'‐ diflurochalcone were competitive.     

Distinct apoptotic blocks mediate resistance to panHER inhibitors in HER2+ breast cancer cells

Despite the development of novel targeted therapies, de novo or acquired chemoresistance remains a significant factor for treatment failure in breast cancer therapeutics. Neratinib and dacomitinib are irreversible panHER inhibitors, which block their autophosphorylation and downstream signaling. Moreover, neratinib and dacomitinib have been shown to activate cell death in HER2-overexpressing cell lines. Here we showed that increased MCL1 and decreased BIM and PUMA mediated resistance to neratinib in ZR-75-30 and SKBR3 cells while increased BCL-XL and BCL-2 and decreased BIM and PUMA promoted neratinib resistance in BT474 cells. Cells were also cross-resistant to dacomitinib. BH3 profiles of HER2+ breast cancer cells efficiently predicted antiapoptotic protein dependence and development of resistance to panHER inhibitors. Reactivation of ERK1/2 was primarily responsible for acquired resistance in SKBR3 and ZR-75-30 cells. Adding specific ERK1/2 inhibitor SCH772984 to neratinib or dacomitinib led to increased apoptotic response in neratinib-resistant SKBR3 and ZR-75-30 cells, but we did not detect a similar response in neratinib-resistant BT474 cells. Accordingly, suppression of BCL-2/BCL-XL by ABT-737 was required in addition to ERK1/2 inhibition for neratinib- or dacomitinib-induced apoptosis in neratinib-resistant BT474 cells. Our results showed that different mitochondrial apoptotic blocks mediated acquired panHER inhibitor resistance in HER2+ breast cancer cell lines as well as highlighted the potential of BH3 profiling assay in prediction of panHER inhibitor resistance in breast cancer cells.     

Integrating HIV services and other health services: A systematic review and meta-analysis

BackgroundIntegration of HIV services with other health services has been proposed as an important strategy to boost the sustainability of the global HIV response. We conducted a systematic and comprehensive synthesis of the existing scientific evidence on the impact of service integration on the HIV care cascade, health outcomes, and cost-effectiveness.Methods and findingsWe reviewed the global quantitative empirical evidence on integration published between 1 January 2010 and 10 September 2021. We included experimental and observational studies that featured both an integration intervention and a comparator in our review. Of the 7,118 unique peer-reviewed English-language studies that our search algorithm identified, 114 met all of our selection criteria for data extraction. Most of the studies (90) were conducted in sub-Saharan Africa, primarily in East Africa (55) and Southern Africa (24). The most common forms of integration were (i) HIV testing and counselling added to non-HIV services and (ii) non-HIV services added to antiretroviral therapy (ART). The most commonly integrated non-HIV services were maternal and child healthcare, tuberculosis testing and treatment, primary healthcare, family planning, and sexual and reproductive health services. Values for HIV care cascade outcomes tended to be better in integrated services: uptake of HIV testing and counselling (pooled risk ratio [RR] across 37 studies: 1.67 [95% CI 1.41–1.99], p < 0.001), ART initiation coverage (pooled RR across 19 studies: 1.42 [95% CI 1.16–1.75], p = 0.002), time until ART initiation (pooled RR across 5 studies: 0.45 [95% CI 0.20–1.00], p = 0.050), retention in HIV care (pooled RR across 19 studies: 1.68 [95% CI 1.05–2.69], p = 0.031), and viral suppression (pooled RR across 9 studies: 1.19 [95% CI 1.03–1.37], p = 0.025). Also, treatment success for non-HIV-related diseases and conditions and the uptake of non-HIV services were commonly higher in integrated services. We did not find any significant differences for the following outcomes in our meta-analyses: HIV testing yield, ART adherence, HIV-free survival among infants, and HIV and non-HIV mortality. We could not conduct meta-analyses for several outcomes (HIV infections averted, costs, and cost-effectiveness), because our systematic review did not identify sufficient poolable studies. Study limitations included possible publication bias of studies with significant or favourable findings and comparatively weak evidence from some world regions and on integration of services for key populations in the HIV response.ConclusionsIntegration of HIV services and other health services tends to improve health and health systems outcomes. Despite some scientific limitations, the global evidence shows that service integration can be a valuable strategy to boost the sustainability of the HIV response and contribute to the goal of ‘ending AIDS by 2030’, while simultaneously supporting progress towards universal health coverage.

Caroline Bulstra and co-workers assess evidence on the benefits of service integration in the HIV care cascade.     

Antimicrobial activity of some sulfonamide derivatives on clinical isolates of Staphylococus aureus

Background

Human infections with non-O1, non-O139 V. cholerae have been described from Laos. Elsewhere, non cholera-toxin producing, non-O1, non-O139 V. cholerae have been described from blood cultures and ascitic fluid, although they are exceedingly rare isolates.

Case presentation

We describe a farmer who died with Vibrio cholerae O21 bacteremia and peritonitis in Vientiane, Laos, after eating partially cooked apple snails (Pomacea canaliculata) and mussels (Ligumia species). The cultured V. cholerae were non-motile. PCR detected ompW and toxR gene regions but not the ctxA, ompU, omp K and TCP gene regions. Although the organisms lacked flagellae on scanning electron microscopy, they possessed the Vibrio flagellin flaA gene.

Conclusion

Severe bacteremic non-O1, non-O139 V. cholerae is reported from Laos. The organisms were unusual in being non-motile. They possessed the Vibrio flagellin flaA gene. Further research to determine the reasons for the non-motility and virulence is required.     

A novel in vitro method for the detection and characterization of photosensitizers

Photoactivation and binding of photoactive chemicals to proteins is a known prerequisite for the formation of immunogenic photoantigens and the induction of photoallergy. The intensive use of products and the availability of new chemicals, along with an increasing exposure to sun light contribute to the risk of photosensitizing adverse reactions. Dendritic cells (DC) play a pivotal role in the induction of allergic contact dermatitis. Human peripheral blood monocyte derived dendritic cells (PBMDC) were thus perceived as an obvious choice for the development of a novel in vitro photosensitization assay using the modulation of cell surface protein expression in response to photosensitizing agents. In this new protocol, known chemicals with photosensitizing, allergenic or non-allergenic potential were pre-incubated with PBMDCs prior to UVA irradiation (1 J/cm(2)). Following a 48 h incubation, the expression of the cell surface molecules CD86, HLA-DR and CD83 was measured by flow cytometry. All tested photosensitizers induced a significant and dose-dependent increase of CD86 expression after irradiation compared to non-irradiated controls. Moreover, the phototoxicity of the chemicals could also be determined. In contrast, (i) CD86 expression was not affected by the chosen irradiation conditions, (ii) increased CD86 expression induced by allergens was independent of irradiation and (iii) no PBMDC activation was observed with the non-allergenic control. The assay proposed here for the evaluation of the photoallergenic potential of chemicals includes the assessment of their allergenic, phototoxic and toxic potential in a single and robust test system and is filling a gap in the in vitro photoallergenicity test battery.     

Antiepileptic drugs: Impacts on human serum paraoxonase‐1

Serum paraoxonase (PON1) is a key enzyme related to high‐density lipoprotein (HDL)‐cholesterol particle. It can prevent the oxidation of low‐density lipoprotein (LDL) and HDL. The present article focuses on the in vitro inhibition role of some antiepileptic drugs (AEDs) such as valproic acid, gabapentin, primidone, phenytoin, and levetiracetam on human paraoxonase (hPON1). Therefore, PON1 was purified from human serum with a specific activity of 3976.36 EU/mg and 13.96% yield by using simple chromatographic methods. The AEDs were tested at various concentrations, which showed reduced in vitro hPON1 activity. IC₅₀ values for gabapentin, valproic acid, primidone, phenytoin, and levetiracetam were found to be 0.35, 0.67, 0.87, 6.3, and 53.3 mM, respectively. K_i constants were 0.261 ± 0.027, 0.338 ± 0.313, 0.410 ± 0.184, 10.3 ± 0.001, and 43.01 ± 0.003 mM, respectively. Gabapentin exhibited effective inhibitory activity as compared with the other drugs. The inhibition mechanisms of all compounds were noncompetitive.