Congenital methemoglobinemia due to NADH-methemoglobin reductase deficiency in three Indian families

Congenital methemoglobinemia is a relatively rare clinical disorder characterized by life-long cyanosis, caused by either an inherited mutant hemoglobin (Hb-M) or deficiency of physiologically active NADH-dependent methemoglobin reductase (NADH-MR). NADH-MR deficiency leads to two different types of recessive congenital methemoglobinemia. In type I, cyanosis is the only major symptom and NADH-MR deficiency is restricted only to the red blood cells. In type II, cyanosis is associated with severe mental retardation and neurological impairment. The objective of this study is to establish the cause of cyanosis in our cases of congenital methaemoglobinemia. Erythrocyte NADH-MR activity was assayed spectrophotometrically. Spectral analysis of the hemolysate treated with potassium ferricyanide was recorded between 400-700 nm and Hb electrophoresis on starch gel at pH 7.0 was done to rule out the presence of Hb-M. NADH-MR deficiency was detected in 3 families. There was a history of consanguinity in one of these cases. The three propositi presented with breathlessness, fever and peripheral cyanosis. There was no history of cardiac illness or exposure to drugs and chemicals. There were no signs and symptoms of mental retardation. The presence of Hb-M was ruled out. Hb-A2, Hb-F, G6PD activity and reduced glutathione levels were normal. NADH-MR activity in all the cases ranged from 4.1 to 9.2 IU/g Hb (normal range 7.0-24.0 IU/g Hb). We describe NADH-MR deficiency in three unrelated cases (age 4 months to 6 years) where the activity of the enzyme was 30-40% of normal. These three cases of congenital methemoglobinemia are due to type-I NADH-MR deficiency without mental retardation.     

Preimplantation embryo morphology following early luteal phase anti-nidatory treatment with mifepristone (RU486) in the rhesus monkey

The ultrastructural characteristics of peri-implantation stage embryos recovered on day 6 after ovulation from rhesus monkeys with or without mifepristone (RU486) treatment during the early luteal phase were examined in the present study. Monkeys were randomly allocated to two groups; group 1 animals were injected s.c. with 2 ml vehicle (1:4, benzyl benzoate: olive oil, v/v, n = 21) and group 2 animals received a single dose of mifepristone (2 mg/kg body weight, w/v, n = 30) in the same volume of vehicle on day 2 after ovulation in mated cycles. On day 6 after ovulation, female monkeys of both groups were laparotomized and their reproductive tracts were flushed to retrieve preimplantation stage embryos. Embryos that showed frank degeneration or desynchrony on gross microscopical examination were not included in the present study. Preimplantation embryo growth on day 6 after ovulation was significantly (P < 0.05) affected in the morula-blastocyst transition stage in mifepristone-treated monkeys compared with that in the control group of monkeys. Ultrastructurally, administration of mifepristone on day 2 after ovulation depressed preimplantation stage embryo development, characterized by loss of cell polarity, lack of mitochondrial maturity, and lack of differentiation in trophoblast cells. Furthermore, preimplantation embryos from mifepristone-treated animals displayed a higher occurrence of inter-blastomere space, intra-cytoplasmic vacuoles, myelinoid bodies, accumulation of lipid droplets, lysosomes, lipofuscins, autophagosomes and multivesicular bodies. Collectively, it appears that the developmental potential of preimplantation embryos was significantly compromised in mifepristone-treated cycles.     

Spermicidal activity of chelated complexes of bis(cyclopentadienyl)vanadium(IV)

Transition metal complexes containing vanadium IV have been shown to modulate the cellular redox potential and catalyse the generation of reactive oxygen intermediates (ROI). Since sperm function is exquisitely susceptible to ROI, we examined the effects of stable chelate complexes of vanadocenes on human sperm motility. We synthesized seven structurally distinct chelate complexes of bis(cyclopentadienyl)vanadium(IV) with bidentate ligands [i.e. vanadocene acetylacetonato monotriflate (VDacac), vanadocene hexafluoro acetylacetonato monotriflate (VDHfacac), vanadocene N-phenyl benzohydroxamato monotriflate (VDPH), vanadocene acethydroxamato monotriflate (VDH), vanadocene catecholate (VDCAT), vanadocene bipyridino ditriflate (VDBPY), and vanadocene dithiocarbamate monotriflate (VDDTC)], and evaluated their spermicidal activity using computer-assisted sperm analysis (CASA; Hamilton-Thorne). All seven chelate complexes of vanadocene elicited potent spermicidal activity at micromolar concentrations (EC50 values: 3.9-106 microM) without affecting the sperm acrosome integrity. The catecholate and acetylacetonate complexes of vanadocene were the most active and the bipyridyl complex the least active with an order of efficacy VDCAT > VDacac > VDDTC > VDPH > VDH > VDHfacac > VDBPY. The spermicidal activity of chelate complexes of vanadocenes was rapid and irreversible since the treated spermatozoa underwent apoptosis, as determined by the flow cytometric analysis of mitochondrial membrane potential, surface annexin V binding assay, in-situ nick-end labelling of sperm nuclei, and confocal laser scanning microscopy. These results provide unprecedented evidence that chelate complexes of vanadocene with bidentate ligands have spermicidal and apoptosis inducing properties. These vanadocene complexes, especially VDacac, may be useful as contraceptive agents.      

Rapid tyrosine phosphorylation of Grb2 and Shc in T cells exposed to anti-CD3, anti-CD4, and anti-CD45 stimuli: differential effects of aging

Two adapter proteins, Grb2 and Shc, have recently been implicated in the transmission of activation signals from the stimulated T cell receptor to Ras. We show here that in vitro stimulation of mouse splenic T cells with crosslinked anti-CD3 antibody leads within 30 s to phosphorylation of both Grb2 and Shc. Treatment with crosslinked anti-CD45 antibody leads to phosphorylation of Grb2 and also to a slight retardation in the mobility of this protein in an SDS polyacrylamide gel; both changes are seen within 30 s of crosslinking. Crosslinked anti-CD4 antibody leads to phosphorylation of Shc and to the phosphorylation of a 30-kDa protein that cross-reacts with anti-Grb2 antibodies. Aging leads to a decline in CD3-stimulated phosphorylation of Shc (but not Grb2), and to an increase in CD4-stimulated phosphorylation of Grb2, Shc, and the 30-kDa Grb2-like protein. Increased tyrosinephosphorylation of Grb2 after exposure to either anti-CD3 or anti-CD45 suggests that Grb2 may be a common substrate for both CD3-linked kinases and the CD45 phosphatase. The differences between T cells from young and old mice suggest that aging may lead to a set of alterations in kinase/substrate coupling that contribute to immune dysfunction in the elderly, and that activation of the Ras pathway might be impaired by aging in T lymphocytes.     

Disseminated histoplasmosis in an immunocompetent individual--a case report

We report a rare case of disseminated histoplasmosis in a immunocompetent young adult person involving bone marrow, liver, spleen and oral cavity. He presented with oral ulcers, weight loss and pancytopenia. His bone marrow aspiration examination revealed Histoplasma capsulatum.     

Characterization of phage-specific transfer RNA molecules coded by Vibrio eltor phage e4

Transfer RNAs were isolated from phage e4-infected Vibrio eltor Mak 757 cells. These were aminoacylated with 14 individual 3H-labeled L-amino acids. Hybridization of these [3H]aminoacyl-tRNAs with phage e4 DNA revealed that the phage e4 encodes tRNAs for arginine, tryptophan, tyrosine, leucine, and isoleucine. Direct aminoacylation of phage-coded tRNA molecules isolated from phage DNA-RNA hybrids also confirmed this observation.