Concomitant dysregulation of androgen secretion and dysfunction of adipose tissue induced insulin resistance

Hyperandrogenism and hyperinsulinemia have resulted from dysfunction of the theca cell of the ovary and adipose tissue and each one potentiates the other in patients with androgen excess disorders e.g., polycystic ovary disease and idiopathic hirsutism. Possible external and/or internal triggers can produce such cellular dysfunction. There is evidence that sodium valproate acts as a trigger of cellular dysfunction and produces both hyperinsulinemia and hyperandrogenism. Therefore, the elimination of these triggers can help the patients to recover from hyperinsulinemia, insulin resistance and hyperandrogenism.     

Laccase production by the white-rot fungus Termitomyces clypeatus

Laccase was detected in the culture filtrate of white-rot fungus Termitomyces clypeatus. The enzyme was found at the late phase of submerged growth in a medium containing glucose or cellulose as the carbon source. The present study indicates that laccase produced by T. clypeatus is an intracellular enzyme, released in the medium due to cell lysis at the end of the growing phase. Laccase produced by T. clypeatus is different from the extracellular polyphenol oxidase of T. albuminosus, also produced at the late phase of growth. This is the first report of laccase production by a Termitomyces sp.     

Successful renal transplantation in a family with a novel mutation in COL4A3 gene and autosomal recessive Alport syndrome

Alport syndrome (AS) is an inherited disorder of basement membranes caused by mutations affecting specific proteins of the type IV collagen family, presenting with nephropathy and extrarenal manifestations such as sensorineural deafness and ocular anomalies. Ten percentage to 15% of the patients with AS have autosomal recessive (ARAS) due to mutation in either COL4A3 or COL4A4 gene. We report a novel mutation in the COL4A3 gene in an Indian family with ARAS. The above‐mentioned genetic anomaly was a missense variation in exon 26 of the COL4A3 gene (chr2:228137797G>A; c.1891G>A) that resulted in the amino acid substitution of Arginine for Glycine at codon 631 (p.Gly631Arg) that was present in the heterozygous state in the asymptomatic parents and homozygous state in the male offspring who presented with early‐onset end‐stage renal disease, lenticonus and hearing loss. The patient (male offspring) underwent successful renal transplantation with his mother as a donor.     

Identification of the prooxidant site of human ceruloplasmin: A model for oxidative damage by copper bound to protein surfaces

Free transition metal ions oxidize lipids and lipoproteins in vitro; however, recent evidence suggests that free metal ion-independent mechanisms are more likely in vivo. We have shown previously that human ceruloplasmin (Cp), a serum protein containing seven Cu atoms, induces low density lipoprotein oxidation in vitro and that the activity depends on the presence of a single, chelatable Cu atom. We here use biochemical and molecular approaches to determine the site responsible for Cp prooxidant activity. Experiments with the His-specific reagent diethylpyrocarbonate (DEPC) showed that one or more His residues was specifically required. Quantitative [¹⁴C]DEPC binding studies indicated the importance of a single His residue because only one was exposed upon removal of the prooxidant Cu. Plasmin digestion of [¹⁴C]DEPC-treated Cp (and N-terminal sequence analysis of the fragments) showed that the critical His was in a 17-kDa region containing four His residues in the second major sequence homology domain of Cp. A full length human Cp cDNA was modified by site-directed mutagenesis to give His-to-Ala substitutions at each of the four positions and was transfected into COS-7 cells, and low density lipoprotein oxidation was measured. The prooxidant site was localized to a region containing His⁴²⁶ because Cp_H426A almost completely lacked prooxidant activity whereas the other mutants expressed normal activity. These observations support the hypothesis that Cu bound at specific sites on protein surfaces can cause oxidative damage to macromolecules in their environment. Cp may serve as a model protein for understanding mechanisms of oxidant damage by copper-containing (or -binding) proteins such as Cu, Zn superoxide dismutase, and amyloid precursor protein.     

Protective effect of granulocyte-colony stimulating factor against amphotericin B-induced myelosuppression in vitro

Summary Amphotericin B causes suppression of bone marrow (BM) progenitor cells in vitro . Granulocyte colony stimulating factor (G-CSF) enhances the proliferation of myeloid cells. The present study defines the role of G-CSF in preventing amphotericin B-induced myelosuppression. G-CSF increased the proliferative potential of BM and protected against amphotericin B-induced myelosuppression if it was added to the medium during the early phase of exposure of BM to amphotericin B. Monoclonal antibodies to tumour necrosis factor-α (TNF) or interferon-γ (IFN) inhibited the myelosuppression partially: simultaneous presence of both these antibodies completely abrogated this suppression, suggesting that both TNFα and IFNγ were involved in amphotericin-induced myelosuppression. TNF- or IFN- induced suppression of BM was also inhibited by G-CSF. These data suggest that G-CSF prevents the amphotericin B-induced myelosuppression by antagonizing the suppressive effects of TNF and IFN and by enhancing the proliferative activity of BM.     

Noncirrhotic portal fibrosis/idiopathic portal hypertension: APASL recommendations for diagnosis and treatment

The Asian Pacific Association for the Study of the Liver (APASL) Working Party on Portal Hypertension has developed consensus guidelines on the disease profile, diagnosis, and management of noncirrhotic portal fibrosis and idiopathic portal hypertension. The consensus statements, prepared and deliberated at length by the experts in this field, were presented at the annual meeting of the APASL at Kyoto in March 2007. This article includes the statements approved by the APASL along with brief backgrounds of various aspects of the disease.     

Analysis of platelet adhesion to a collagen-coated surface under flow conditions: the involvement of glycoprotein VI in the platelet adhesion

Platelet adhesion to the exposed surface of the extracellular matrix in flowing blood is the first and critical reaction for in vivo thrombus formation. However, the mechanism of this in vivo platelet adhesion has yet to be studied extensively. One of the reasons for this is the lack of a practical assay method for assessing platelet adhesion under flow conditions. We have devised an assay method (the fluorescent adhesion assay) that is based on the technique originally reported by Hubbell and McIntire (Biomaterials 7:354, 1986) with some modifications to make it more amenable for assaying small samples and have developed an analysis method to quantify the extent of platelet adhesion and aggregation from fluorescence images by using a computer-assisted image analysis system. In our assay, platelet adhesion, expressed as the percentage of the area covered by adhered platelets, was found to increase biphasically as a function of time. In the first phase, platelets interacted with the coated collagen, transiently stopping on the surface; we called this reaction the temporary arrest. In the second phase, platelets adhered much more rapidly and permanently on the surface, and this adhesion was dependent on the shear rate; platelets formed aggregates in this phase. We used our assay to analyze the effects of platelet aggregation inhibitors on platelet adhesion. All three examined inhibitors, EDTA (10 mmol/L), antiglycoprotein (GP) IIb/IIIa, and GRGDS peptide (1 mmol/L), inhibited the second phase adhesion in flowing blood. Furthermore, GPVI-deficient platelets also showed defective second-phase adhesion under the same conditions. These results suggested that GPIIb/IIIa activation and GPVI contribute to the reaction inducing the second phase. The second-phase adhesion has been extensively investigated, and the consensus is that this reaction is mainly attributable to the platelet-platelet interaction. In this report, we were able to detect an earlier reaction, the temporary arrest. This temporary arrest would reflect the fast and weak interaction between platelet GPIb/IX and collagen-von Willebrand factor complexes on the collagen-coated surface.