[The clinical significance of Th17 cells in patients with myelodysplastic syndrome and iron overload].

Objective: To study the significance of Th17 cells in patients with myelodysplastic syndrome (MDS) and iron overload. Methods: A total of 77 patients with MDS admitted to Guangzhou First People's Hospital were enrolled from January 2017 to December 2018,who were divided into iron overload group (37 cases) with serum ferritin (SF) over 1000 µg/L and non-ferrous overload group(40 cases). CD(4)(+)T cells in peripheral blood (PB) and bone marrow (BM) were sorted by flow cytometry. The ratio of Th17 cells and cells with abnormal karyotype were compared. IL-17 and IL-6 protein and RNA expression were detected by ELISA and quantitative real-time PCR(qRT-PCR). Results: The proportions of Th17 cells in PB and BM in iron overload group were significantly higher than those in non-iron overload group [(41.06±0.96)% vs. (26.80±1.21)%; (47.39±1.60)% vs. (34.29±1.03)%; P<0.01]. The Th17 positive cells with abnormal karyotype in iron overload group were more than those in non-iron overload group[(4.96±0.53)% vs. (3.67±0.12)% in PB; (10.06±1.67)% vs. (4.36±0.43)% in BM; P<0.01]. Similarly,the protein levels as well as mRNA expression of IL-6 and IL-17 in patients with iron overload were significantly higher than those in non-iron overload group (P<0.01 both in PB and BM). Conclusions: As hematopoietic regulators secreted by Th17 cells, the expression of IL-6 and IL-17 in MDS patients with iron overload are elevated. This may predict the influence of these factors to the differentiation of Th17 cells.

Transparent Tiger barb Puntius tetrazona, a fish model for in vivo analysis of nocardial infection.

Nocardiosis afflicts multiple species of cultured fish, resulting in substantial economic losses to the aquaculture industry, however, lack of detailed knowledge on disease pathogenesis has hampered the development of effective prevention and control strategies. In this study, we injected a green fluorescent protein (GFP)-labeled Nocardia seriolae strain into a transparent mutant strain of Tiger barb (Puntius tetrazona) to monitor tissue pathogen accumulation and tissue damage in vivo, and to clarify the relationship between pathogenic processes and overt symptoms. GFP-labeled bacteria were phagocytized by leukocytes and could proliferate within these cells, which in turn led to leukocyte aggregation, leukocyte death, and granuloma formation. In addition, intracellular bacteria could permanently colonize various tissues via leukocyte circulation, causing multi-organ infection as revealed by changes of tissue transparency. Histology revealed granulomatous lesions in organs such as muscle, kidney, and spleen that was corresponded to the tissue opacities in vivo. Confocal microscopy confirmed massive accumulations of GFP-labeled bacteria within these granulomas, which often contained a necrotic core. Tiger barb transparency allows for real-time observation of in vivo pathological changes within the same animal, and the pathogenic process can be evaluated based on the shape and size of body opacities. Thus, transparent Tiger barb is a promising model to study the pathogenesis of nocardiosis.

Automated resonance assignment of proteins using heteronuclear 3D NMR. 2. Side chain and sequence-specific assignment.

A sequential assignment protocol for proteins was developed using heteronuclear 3D NMR. The protocol consists of an amino acid type recognition algorithm and a primary sequence mapping algorithm. The former measures the similarity between each detected spin pattern and 20 standard amino acid coupling patterns. Both chemical shift and topologically likeness are considered. The mapping algorithm uses the amino acid type information to direct detected polypeptides to proper position onto protein primary sequence. The assignment protocol can be applied to spin systems generated by many different approaches. We designed a few computer programs to derive a protein's backbone and side chain spin systems using heteronuclear 3D NMR. The results was then input to the sequential assignment protocol. All of the algorithms were tested on NMR data of a 90-residue N-domain of chicken skeletal troponin-C.

A study of hepatitis C virus antibodies and serum alanine amino transferase in blood donors in Hong Kong Chinese.

The reference range of serum alanine amino transferase (ALT) for the local population was established by testing 5,000 random voluntary Chinese blood donors of various age groups of both sexes. In addition, 1,769 serum samples with elevated ALT levels were also collected for anti-HCV assays using both the Abbott and Ortho anti-hepatitis C virus (HCV) assay kits. The relationship between serum ALT and anti-HCV tests was studied and the performances of both kits used were compared. It was found that while the prevalence of serum anti-HCV was 0.4% among hepatitis B surface antigen-negative donors with normal ALT, subjects with ALT between 2 and 3 standard deviations (SD) and greater than 3 SD above the mean level had respective prevalence of anti-HCV 3 and 9.5 times that of the normal ALT subjects. Both anti-HCV kits were found to identify in majority the same positive population among the different groups of subjects studied. In addition, it was observed that for subjects who were anti-HCV-positive, the higher the serum ALT level, the higher the mean anti-HCV ELISA ratio and this observation was similar for both anti-HCV kits used. We conclude that: (1) there is a direct relationship between serum ALT level and anti-HCV positivity by EIA; (2) there is a direct correlation between serum ALT level and anti-HCV ELISA ratio, and (3) both Abbott and Ortho anti-HCV kits perform similarly in the identification of positive serum samples.

Production and properties of alpha-glucosidase from Lactobacillus acidophilus.

Lactobacillus acidophilus IFO 3532 was found to produce only intracellular alpha-glucosidase (alpha-D-glucoside glucohydrolase; EC 3.2.1.20). Maximum enzyme production was obtained in a medium containing 2% maltose as inducer at 37 degrees C and at an initial pH of 6.5. The enzyme was formed in the cytoplasm and accumulated as a large pool during the logarithmic growth phase. Enzyme production was strongly inhibited by 4 microM CuSO4, 40 microM CoCl2, and beef extract; MnSO4 and the presence of proteose peptone and yeast extract in the medium greatly enhanced enzyme production. A 16.6-fold purification of alpha-glucosidase was achieved by (NH4)2SO4 fractionation and DEAE-cellulose column chromatography. The enzyme showed high specificity for maltose. The Km for alpha-p-nitrophenyl-beta-D-glucopyranoside was 11.5 mM, and the Vmax for alpha-p-nitrophenyl-beta-D-glucopyranoside hydrolysis was 12.99 mumol/min per mg of protein. The optimal pH and temperature for enzyme activity were 5.0 and 37 degrees C, respectively. The enzyme activity was inhibited by Hg2+, Cu2+, Ni2+, Zn2+, Ca2+, Co2+, urea, rose bengal, and 2-iodoacetamide, whereas Mn2+, Mg2+, L-cysteine, L-histidine, Tris, and EDTA stimulated enzyme activity. Transglucosylase activity was present in the partially purified enzyme, and isomaltose was the only glucosyltransferase product. Amylase activity in the purified preparation was relatively weak, and no isomaltase activity was detected.