High-precision characterization of quantum-cascade laser frequency response using wavelength modulation spectroscopy.

This paper investigates the impact of the quantum cascade laser's frequency modulation response on its tuning rate and tunability. We show a significant disparity in laser tuning rates and tunability between single and dual-frequency modulation schemes frequently used in typical direct absorption and wavelength modulation spectroscopy (WMS) techniques. We show that the DC-characterized tuning rate of a laser can be reduced significantly under a specific set of modulation frequencies of the laser injection current. We characterize these effects by simultaneous measurements of higher harmonic WMS of methane and nitrous oxide in the 7.8 µm spectral regions. We further show that WMS signal modulation broadening mechanisms and spectral structure, i.e., its zero-crossings and turning points, can be used to quantify such laser-modulation effects and validate laser frequency response under dual modulation schemes.

Use of vegetables for enhancing oxidative stability of omega-3 oils in the powdered state.

The preliminary study examined the effectiveness of various vegetables for the stabilisation of omega-3 oil powders against oxidative deterioration. Purees made from different vegetables (mushroom, brussels sprouts, broccoli, cauliflower, snow peas, tomato, and garlic) were employed for preparation of vegetable-tuna oil emulsions, which were subsequently freeze-dried into powders. Oxipres® data showed that vegetable-tuna oil powders had longer induction periods than neat tuna oil. During accelerated oxidation storage (40 °C/4weeks), eicosapentaenoic and docosahexaenoic acids in the vegetable-tuna oil powders were protected against oxidation, and there were lower levels of headspace secondary and tertiary oxidation products. Whole vegetable purees were suitable protective matrices for omega-3 oils. Of the various vegetable purees examined for protective effects against omega-3 oxidation, mushroom, brussels sprouts, broccoli, and cauliflower were superior to snow peas, garlic and tomato. The antioxidant properties of phytonutrients inherent in various vegetables are likely contributors to protection of omega-3 oil powders against oxidation.

Clonal diversity of Acinetobacter baumannii clinical isolates in Myanmar: identification of novel ST1407 harbouring blaNDM-1.

Recent Acinetobacter baumannii clinical isolates in a teaching hospital in Myanmar comprised three major sequence types (ST2, ST16 and ST23) and two sporadic STs, showing a high resistance rate to carbapenem associated with blaOXA-23 . The NDM-1 encoding gene was identified in only one isolate exhibiting novel ST1407 (a triple-locus variant of ST16).

Is stopping secondary prophylaxis safe in HIV-positive talaromycosis patients? Experience from Myanmar.

OBJECTIVES: The aim of the study was to determine whether it is safe to stop secondary prophylaxis in patients with talaromycosis after immune reconstitution with a sustained increase in CD4 count to ≥ 100 cells/µL after antiretroviral therapy (ART). METHODS: A retrospective cohort analysis was performed in HIV-infected patients treated for talaromycosis between June 2009 and June 2017 in Medical Action Myanmar (MAM) clinics. RESULTS: Among a cohort of 5466 HIV-infected patients, 41 patients were diagnosed with and treated for clinical talaromycosis. All the patients were on ART and had a CD4 count < 100 cells/µL. Of these 41 patients, 24 patients (71%) were skin smear positive for talaromycosis, while results were negative in 17 patients. Median CD4 count and haemoglobin concentration were 24 cells/µL and 7.7 g/dL, respectively. Seventy-three per cent (30) were male. Among the 41 patients, 11 (27%) died and six (15%) were transferred to other centres. Twenty-four patients (58% of the total diagnosed) stopped itraconazole secondary prophylaxis after starting active ART with CD4 counts > 100 cells/µL for at least 1 year. Throughout the duration of follow-up post itraconazole cessation, the observed incidence of relapse was zero with a total follow-up of 93.8 person-years (95% confidence interval 0-4 per 100 person-years). The median (25th, 75th percentile) duration of follow-up post-prophylaxis discontinuation was 2.8 (2.1, 6.3) years. CONCLUSIONS: Secondary prophylaxis can be safely stopped in patients with talaromycosis after immune reconstitution with a sustained increase in CD4 count to ≥ 100 cells/µL after highly active antiretroviral therapy.

First detection of the mcr-1 colistin resistance gene in Escherichia coli from a patient with urinary tract infection in Myanmar.

Colistin-resistance gene mcr-1 was detected in an Escherichia coli sample among 442 clinical isolates collected in a tertiary-care hospital in Yangon, Myanmar, in 2018. This isolate was classified into phylogroup A-ST23 complex and harboured bla CTX-M-15 and bla TEM-1, associated with multiple mutations in quinolone-resistance-determining regions in gyrA and parC.

Black silicon as a platform for bacterial detection.

Surface-enhanced Raman scattering (SERS) shows promise for identifying single bacteria, but the short range nature of the effect makes it most sensitive to the cell membrane, which provides limited information for species-level identification. Here, we show that a substrate based on black silicon can be used to impale bacteria on nanoscale SERS-active spikes, thereby producing spectra that convey information about the internal composition of the bacterial capsule. This approach holds great potential for the development of microfluidic devices for the removal and identification of single bacteria in important clinical diagnostics and environmental monitoring applications.

Evidence for expression of estrogen receptor cofactor messenger ribonucleic acid in the ovary and uterus of domesticated animals (sheep, cow and pig).

Expression levels of estrogen receptor cofactors (coactivators or corepressors) in specific tissue compartments and cells are thought to influence the expression of estrogen responsive genes and thereby influence overall hormonal responsiveness of target tissues. To date, the presence of cofactors has been reported in tissues from humans, rats and mice. We analyzed the presence and distribution of messenger ribonucleic acids (mRNAs) encoding several transcriptional cofactors in the ovary and uterus of three domestic animal species, the sheep, cow and pig. Northern analysis for cofactors SRC-1, GRIP1, RAC3, p300, RIP140, and SPA showed expression in ovaries from all three species. In addition, lower expression of SRC-1, GRIP1, RAC3, p300, and RIP140 mRNAs was observed during the luteal phase (day 10-12 of the estrous cycle) than at estrus (day 0); however, SPA transcript levels remained unchanged. We then examined expression of mRNAs for changing (SRC-1, RIP140) and constitutively expressed (SPA) cofactors in ovine ovaries. SRC-1 and RIP140 transcripts in corpus luteum were lower compared to the surrounding ovarian tissue. SPA mRNA expression, however, was similar in corpus luteum and surrounding tissues. To determine which ovarian cell types express SRC-1, RIP140, and SPA, in situ hybridization was performed on sheep ovaries. Silver grains corresponding to these cofactors were seen in ovarian granulosa, theca and stromal cells, but appeared to be most abundant in the granulosa cells. Expression of SRC-1 and RIP140 in corpus luteum, however, was reduced compared to expression in follicular cells. Finally, we examined cofactor expression in ovine, bovine, and porcine uterus. Northern blot analysis for SRC-1, GRIP1, RAC3, p300, and RIP140 mRNAs showed higher expression in extracts of the endometrium compared to whole uterus. We provide the first evidence for the presence of estrogen receptor cofactor mRNAs in the ovary and uterus of three domestic animal species. We suggest that coactivators are conserved among species and associated with hormonal responsiveness of reproductive tract tissues in sheep, cow and pig.

Expression of estrogen receptor coactivators in the rat uterus.

Nuclear receptor coactivators associate in a ligand-dependent manner with estrogen receptors (ER) and other nuclear receptors, and they enhance ligand-dependent transcriptional activation. This study examined basal coactivator expression in rat uterus to investigate if expression of these genes is regulated by estradiol-17 beta or tamoxifen. Ovariectomized mature and immature rats were injected with estradiol-17 beta, tamoxifen, or vehicle (i.e., sesame oil) alone. Uteri were collected and analyzed for changes in coactivator mRNA expression using Northern blot and in situ hybridization analyses. Constitutive uterine mRNA expression of switch protein for antagonist (SPA), SRC-1, GRIP1, RAC3, RIP140, and p300 mRNAs was observed in control uteri, and treatment with ER ligands did not alter coactivator mRNA levels. The data suggest that expression of these coactivator genes is not sensitive to estradiol or tamoxifen in the rat uterus. No cell type-specific pattern of expression was apparent in uterine sections from mature and immature rats; however, silver grains were more abundant in luminal and glandular epithelial cells compared with the stroma and myometrium, indicating that coactivator mRNA levels vary among the uterine compartments. Thus, to our knowledge, we show for the first time that there is constitutive expression of several uterine nuclear receptor coactivators in a physiological setting that remains insensitive to estrogenic regulation. Furthermore, we speculate that higher constitutive levels of coactivator expression in glandular and luminal epithelial cells may be associated with increased hormonal responsiveness by these uterine compartments.

Synergistic induction of apoptosis in murine hepatoma Hepa1-6 cells by IFN-gamma and TNF-alpha.

In this study, we examined the susceptibility of murine hepatoma Hepa1-6 cells to undergo IFN-gamma- and/or TNF-alpha-induced apoptosis. IFN-gamma or TNF-alpha alone had no demonstrable cytotoxic effects, whereas IFN-gamma and TNF-alpha in combination induced apoptosis drastically in Hepa1-6 cells. During this apoptosis, an increase in caspase-3- and -8-like protease activities and activation of caspase-3, identified by the appearance of its p17 fragment, were observed. Moreover, the cytotoxic induction and caspase-3 activation were effectively inhibited by Z-Asp-CH(2)-DCB (Z-Asp), a caspase inhibitor. Further, an elevation of cytochrome c in the cytosol, in a parallel to activation of caspase-3, was observed in a time-dependent manner. Concurrently, up-regulation of caspase-11 gene expression and processing of procaspase-11 were detected during this apoptosis. These results suggest that the caspase-3 activation, the release of cytochrome c from mitochondria, and increased caspase-11 gene expression involve in synergistic induction of apoptosis in Hepa1-6 cells by IFN-gamma and TNF-alpha.

Nutritional regulation of circulating insulin-like growth factors (IGFs) and their binding proteins in the ovine fetus.

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important for fetal and postnatal development, but the regulation of circulating IGFs and IGFBPs has not been as thoroughly investigated in the maternal/fetal unit as in the adult animal where nutrition status plays a regulatory role. We used the chronically-catheterized, late-gestation ovine model and compared circulating IGFs and IGFBPs levels, and hepatic IGF-I mRNA levels. Following a five-day maternal fast, both IGF-I and IGF-II levels were decreased in the maternal and fetal circulation (P < 0.05), accompanied by a decrease in fetal hepatic IGF-I mRNA levels, but the IGFBP2 level was increased and the IGFBP3 level was decreased in maternal circulation, whereas the IGFBP1 level was increased in fetal circulation. In both fed and fasting states, the infusion of glucose (150% of baseline) did not alter IGFs or IGFBPs in either maternal or fetal circulation. To understand the regulation of the endogenous IGF system, rhIGF-I was infused (6.7 nmol/kg fetus/h) into the fetal circulation. While maternal IGFs or IGFBPs remained unchanged, IGF-I infusion into fetal circulation resulted in an increase in IGF-I, a decrease in IGF-II, and an overall increase in the IGFBPs (P < 0.05). Taken together, circulating IGFs and IGFBPs in the ovine fetus are more sensitive to prolonged nutrient deficit than to a brief glucose increase. The nutrition status therefore regulates the IGF system in maternal and fetal circulation which, in turn, may regulate the nutrient utilization for fetal growth.