Physiological correlates of calcium-accumulating properties of mitochondria: Fish-muscle mitochondria

The mitochondria isolated from the muscles of fish acclimated to grow in different salinities have been studied with reference to their Ca²⁺ uptake capacity and compared to those isolated from fresh-water fish muscle. The results show a drastic response by the mitochondria with reference to their Ca²⁺ uptake function soon after exposure to the stress. Evidence is also presented to suggest an alteration in conformation. This perturbation appears to be the initial response to the stress since the normal state (as that of the fresh-water fish) is restored in course of time. Further, so far there is no indication that the electron transport function and ATP production are affected by the ionic stress conditions. This would support the physiological relevance of the mitochondrial capacity for Ca²⁺ uptake.     

First record of lily thrips, Liothrips vaneeckei Priesner, in Australia (Thysanoptera: Phlaeothripidae)

The first Australian record of the lily thrips, Liothrips vaneeckei Priesner, is reported from a bulb farm in Warragul South, Victoria. It is an occasional pest of Lilium bulbs, both in the field and in storage, particularly in the USA and several European countries, and is also infrequently found in considerable numbers on the corms of orchids.     

Cell proliferation and apoptosis: dual-signal hypothesis tested in tuberculous pleuritis using mycobacterial antigens

Antigens and mitogens have the innate ability to trigger cell proliferation and apoptosis thus exhibiting a dual-signal phenomenon. This dual-signal hypothesis was tested with mycobacterial antigens (PPD and heat killed Mycobacterium tuberculosis - MTB) in tuberculous pleuritis patients where the immune response is protective and compartmentalized. We compared and correlated the cell-cycle analysis and antigen-induced apoptosis in normal and patients' peripheral blood mononuclear cells (PBMCs) and patients' pleural fluid mononuclear cells (PFMCs). In cell-cycle analysis, PFMCs showed good mitotic response with PPD and MTB antigens where 10% and 7% of resting cells entered the S and G2/M phases of cell cycle, respectively. This antigen-induced proliferation of PFMCs correlated well with the lymphocyte transformation test (LTT) results. On the other hand, PFMCs also showed 21% of spontaneous apoptosis, which further increased to 43%, by induction with known apoptotic agent like Dexamethasone (DEX) and the mycobacterial antigens PPD and MTB. Further we demonstrated by anti-CD3 induction experiments that prior activation of cells is prerequisite for them to undergo apoptosis. Our results showed that PPD and MTB antigens induced both cell proliferation and apoptosis in PFMCs, which were pre-sensitized to mycobacterial antigens in vivo. Thus the dual-signal phenomenon was operative against these antigens in tuberculous pleuritis. We also demonstrated that the activated cells are more predisposed to apoptosis.     

Impact of tuberculosis on serum leptin levels in patients with HIV infection

AIM: Tuberculosis (TB) and human immunodeficiency virus (HIV) are classical wasting diseases accompanied by immunosuppression. As leptin is involved in the weight regulation and cellular immunity, we investigated the role of leptin levels in the co-infection of HIV and TB (HIV-TB). METHODS: The study group consists of the patients with asymptomatic HIV infection (n = 20), patients with HIV-TB co-infection (n = 20) and healthy control subjects (n = 20). Serum leptin levels and the concentrations of IFN-gamma, TNF-alpha, IL-12 and IL-4 cytokines were measured by ELISA before the start of the treatment. CD4+ T-cell counts were determined in patients with HIV and HIV-TB by flow cytometry. Body mass index (BMI) of the study subjects was calculated. RESULTS: Serum leptin levels and BMI were significantly lower in the patients with HIV-TB than control and HIV subjects. Multivariate regression analysis showed that serum leptin concentration was significantly dependent on BMI and sex but not on age and the disease groups. The leptin levels did not correlate either with CD4+ T-cell counts or with any of the serum cytokines in HIV and HIV-TB patients. CONCLUSION: Thus our finding suggests that the leptin concentrations were strongly associated with BMI and gender but not with the disease state or with the circulating cytokine levels.     

Insulin receptor tyrosine kinase activity in monocytes of type 2 diabetes mellitus patients receiving oral L-lysine

The action of lysine as an antidiabetic agent was examined in human volunteers. Eight patients with type 2 DM were orally supplemented with L-lysine hydrochloride 1 g/day in two doses along with antidiabetic tablets (glyciphage or chlorformine), for a period of two months. Periodically their plasma fasting sugar and insulin receptor tyrosine kinase activity was measured in their monocytes. Eight normal healthy volunteers served as controls for comparison of receptor tyrosine kinase activity. Insulin receptor tyrosine kinase was isolated from monocytes by immunoprecipitation and the activity was determined using exogenous substrate poly glu-tyr (4:1) and radioactive ATP. Phosphorylated peptide was separated by electrophoresis and quantified using a liquid scintillation system. The enzyme activity was significantly low (22074 +/- 1728 dpm/ml immunoprecipitate) in subjects with diabetes when compared to non-diabetic control group (50,775 +/- 3597). Lysine treatment enhanced the enzyme activity by 31% in patients with diabetes and decreased their blood sugar by 27%.     

Prevalence of HIV,Hepatitis B and C Infections and an Assessment of HCV-Genotypes and Two IL28B SNPs among People Who Inject Drugs in Three Regions of Nepal

As part of a comprehensive health care programme for people who use drugs in Nepal, HIV and viral hepatitis B and C status—including risk factors, HCV-genotypes and co-infections—as well as two IL28B Single-nucleotide polymorphisms (SNPs) were assessed for a random sample of 401 people who inject drugs in three regions of Nepal: mid-western Terrai (Nepalgunj), the eastern region (Dharan, Biratnagar) and the central region (Kathmandu, Lalitpur and Chitwan). Individuals were included who showed at least a minimum of health care seeking behaviour. This latter criterion was defined by being registered with any organisation offering health services. The average age of the participants was 30.5 yrs, and the average length of intravenous drug use was 8.5 yrs. The prevalence rates of HBsAg, anti-HIV antibodies and HCV-RNA were 3.5%, 13.8% and 41.9%, respectively. Spontaneous HCV clearance was evident in 16% of all of those who tested positive for anti-HCV antibodies. Independent risk factors for HCV-RNA positivity were age, gender, geographical region, duration of injecting drug use, history of imprisonment and HIV co-infection. In the age group ≤24 yrs, the rate of spontaneous HCV clearance was 43.5%. Overall, 59.8% of HCV infections were caused by HCV genotype 3 and 40.2% by HCV genotype 1. No other HCV genotypes were identified in this study. The IL28B SNP rs12979860 and rs8099917 were identified in 122 patients, and 75.4% of all participants had both favourable genotypes rs12979860 C/C and rs8099917 T/T.     

Isthmin is a novel secreted angiogenesis inhibitor that inhibits tumour growth in mice

Anti‐angiogenesis represents a promising therapeutic strategy for the treatment of various malignancies. Isthmin (ISM) is a gene highly expressed in the isthmus of the midbrain–hindbrain organizer in Xenopus with no known functions. It encodes a secreted 60 kD protein containing a thrombospondin type 1 repeat domain in the central region and an adhesion‐associated domain in MUC4 and other proteins (AMOP) domain at the C‐terminal. In this work, we demonstrate that ISM is a novel angiogenesis inhibitor. Recombinant mouse ISM inhibited endothelial cell (EC) capillary network formation on Matrigel through its C‐terminal AMOP domain. It also suppressed vascular endothelial growth factor (VEGF)‐basic fibroblast growth factor (bFGF) induced in vivo angiogenesis in mouse. It mitigated VEGF‐stimulated EC proliferation without affecting EC migration. Furthermore, ISM induced EC apoptosis in the presence of VEGF through a caspase‐dependent pathway. ISM binds to αvβ5 integrin on EC surface and supports EC adhesion. Overexpression of ISM significantly suppressed mouse B16 melanoma tumour growth through inhibition of tumour angiogenesis without affecting tumour cell proliferation. Knockdown of isthmin in zebrafish embryos using morpholino antisense oligonucleotides led to disorganized intersegmen‐tal vessels in the trunk. Our results demonstrate that ISM is a novel endogenous angiogenesis inhibitor with functions likely in physiological as well as pathological angiogenesis.     

Sperm characteristics in plains (Bison bison bison) versus wood (Bison bison athabascae) bison

The objective was to compare sperm characteristics between the two subspecies of North American bison, plains bison (Bison bison bison) and wood bison (Bison bison athabascae). Frozen-thawed ejaculated sperm from age-matched plains (n = 3) and wood (n = 2) bison were evaluated for morphometry, motility, viability, protein profile, and in vitro fertilization characteristics. Sperm morphometry and motility were assessed with computer-based systems, viability was assessed with SYBR-14 and propidium iodide, and fertilizing ability was determined using a heterologous in vitro fertilization system (using bovine oocytes). For plains versus wood bison, there were significant differences for head width (4.76 ± 0.22 vs 4.71 ± 0.19 μm; mean ± SD), head area (35.64 ± 1.91 vs 34.72 ± 2.64 μm²), head perimeter (23.61 ± 0.68 vs 23.31 ± 0.98 μm), midpiece length (14.58 ± 0.4 vs 14.36 ± 0.51 μm), midpiece width (0.81 ± 0.06 vs 0.79 ± 0.07 μm), and tail length (46.61 ± 2.15 vs 45.98 ± 2.08 μm). However, there was no significant difference in head length (overall, 9.04 ± 0.37 μm), progressive motility (41.16 ± 8.39%), or viability (41.58 ± 5.58%). Based on two-dimensional gel electrophoresis, 93 out of 113 protein spots were similar in their expression patterns. Furthermore, we inferred that differences in sperm biometry between these subspecies did not affect in vitro fertilization percentage (overall, 82.62 ± 12.13%). Based on these findings, we concluded that plains bison were an appropriate research model for developing reproductive technologies for wood bison.