Sex differences in gallbladder bile acid composition and hepatic steroid 12 alpha-hydroxylase activity in hamsters

The gallbladder bile acid composition and the activity of the hepatic steroid 12 alpha-hydroxylase were determined in male and female hamsters. Cholic acid, chenodeoxycholic acid, and deoxycholic acid were the major bile acids in both sexes; in addition, 7-ketodeoxycholic acid and lithocholic acid were present. A sex-linked difference in the ratio of cholic acid (plus its metabolites) to chenodeoxycholic acid (plus its metabolite) was observed. The ratio was 1.93 +/- 0.39 in males and 2.74 +/- 0.54 in females. Another sex-linked difference was found in the activity of the 12 alpha-hydroxylase. The extent of the 12 alpha-hydroxylation of 7 alpha-hydroxycholest-4-en-3-one to yield 7 alpha, 12 alpha-dihydroxycholest-4-en-3-one was about two times greater in the microsomal suspension obtained from the liver of female hamsters than in that of male hamsters. A positive correlation between the 12 alpha-hydroxylase activity and the ratio of cholic acid/chenodeoxycholic acid was also observed. These results strongly support the proposal that the activity of the 12 alpha-hydroxylase is the major factor in determining the relative proportion of cholic acid and chenodeoxycholic acid formed from cholesterol in the liver.     

Isolation and primary structure of endorphin from salmon pituitary glands.

Endorphin has been isolated from an acid acetone extract of the pituitary of the salmon $\text{Oncorhynchus}\text{keta}$ by ion exchange chromatography and gel filtration. Sequence analysis revealed it to be a nonacosapeptide with following primary structure: Ac-Tyr-Gly-Gly-Phe-Met-Lys-Pro-Tyr-Thr-Lys-Gln-Ser-His-Lys-Pro-Leu-Ile-Thr-Leu-Leu-Lys-His- Ile-Thr-Leu-Lys-Asn-Glu-Gln-OH. It appears that the amino terminal segment which is necessary for analgesic activity is conserved through the evolution of vertebrate except for the blocking of the amino terminal of salmon endorphin.     

Quantitative determination of sulfated glycopeptide by two-dimensional electrophoresis on cellulose acetate membrane

Quantitative determination of the sulfated glycoproteins present in tissue and secretion fluid was performed. After digestion of the specimen with pronase in order to convert glycoproteins to glycopeptides, the sulfated glycopeptides were separated from a mixture of acidic glycans (glycosaminoglycans, sialoglycopeptides and sulfated glycopeptides) by two-dimensional electrophoresis on cellulose acetate membrane [(1986) J. Biochem. Biophys. Methods 12, 239-246]. After staining with alcian blue, the spot of sulfated glycopeptide on the cellulose acetate membrane was cut out, and then only the dye bound to the sulfated glycopeptide was extracted with a 5% cetylpyridinium chloride solution at 100 degrees C for 15 min. The extract was then measured by absorbance at 615 nm using an authentic sulfated glycopeptide as a standard. This method facilitated the determination of sulfated glycopeptides, which were separated from other acidic glycans, within the range 0-25 micrograms.     

Radioiodination of proteins using prosthetic group: a convenient way to produce labelled proteins with in vivo stability.

Radiolabelled peptides can provide new approaches for radiopharmaceutical development. Several prosthetic groups have been developed for radioiodination of proteins in order to minimize in vivo dehalogenation. In this work, the prosthetic group N-succinimidyl 4-[131I]iodobenzoate ([131I]SIB) was obtained by an alternative procedure that employs Cu(I) assisted radioiododebromination to produce p-[131I]iodobenzoic acid with a radiochemical yield of 92.73 +/- 1.51% (N = 6), followed by the reaction with TSTU (O-(N-succinimidyl)-N,N,N'N'-tetramethyluronium) in alkaline medium. The HPLC profile of the final product, revealed that [131I]SIB was obtained with a radiochemical purity of 98.19 +/- 1.14% (N = 6 Swiss mices (normal group) and animals with inflammation focus developed on the right thigh by tupertine injection) were injected with human immunoglobulin (IgG) radioiodinated with [131I]SIB and by direct method (Iodogen). The comparison of results showed a fast blood clearance, better target organ/background relation and low uptake in thyroid and stomach (p < 0.01) for the protein labelled with [131I]SIB, what suggests a greater in vivo stability.     

Ostrich antithrombin III: kinetics and mechanism of inhibition of ostrich thrombin

A kinetic investigation of ostrich thrombin specificity, its regulation and evolutionary development in comparison to those of other well-characterised species may contribute to the understanding of the structure-function relationships of thrombin. Antithrombin III (ATIII) was purified from ostrich plasma by heparin-Sepharose and Super Q-650S chromatography. It exhibited a M(r) of 59.2K and a pI in the range of 5.2-6.0. The ostrich N-terminal sequence was compared to those of other known species and showed the highest identity with rabbit ATIII (31%). Inhibition studies included the interaction of ostrich and human ATIII with bovine, human and ostrich thrombin. At a 2:1 molar ratio of ostrich ATIII to enzyme, 20 and 40% remaining activity was found for bovine and ostrich thrombin, respectively. Ostrich thrombin exhibited a pH and temperature optimum of 9.0 and 60 degrees C, respectively. Hydrolysis of seven peptide p-nitroanilide substrates by ostrich thrombin revealed D-Phe-Pip-Arg-pNA (k(cat)/K(m)=9.65 microM(-1)s(-1)) as the substrate with the highest catalytic efficiency. The effect of monovalent cations on ostrich thrombin catalysis revealed enhanced activity with Na(+). The calculated K(i) values for the complex formation between ostrich thrombin and ostrich (9.29 x 10(-11)M) and human (9.66 x 10(-11)M) ATIII are comparable to reported results. The results obtained from the present study confirmed that ostrich thrombin and ATIII are closely related to the corresponding molecules of other species in terms of physicochemical and kinetic properties.     

Superoxide scavenging activity of pirfenidone-iron complex

Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide () scavenging activities of PFD and the PFD-iron complex by electron spin resonance (ESR) spectroscopy, luminol-dependent chemiluminescence assay, and cytochrome c reduction assay. Firstly, we confirmed that the PFD-iron complex was formed by mixing iron chloride with threefold molar PFD, and the complex was stable in distillated water and ethanol. Secondary, the PFD-iron complex reduced the amount of produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount of released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis.     

Highly pathogenic H5N1 influenza virus causes coagulopathy in chickens

Severe hemorrhage at multiple organs is frequently observed in chickens infected with highly pathogenic avian influenza (HPAI) A viruses. In this study we examined whether HPAI virus infection leads to coagulation disorder in chickens. Pathological examinations showed that the fibrin thrombi were formed in arterioles at the lung, associated with the viral antigens in endothelial cells of chickens infected intravenously with HPAI virus. Hematological analyses of peripheral blood collected from the chickens revealed that coagulopathy was initiated at early stage of infection when viral antigens were detected only in the endothelial cells and monocytes/macrophages. Furthermore, gene expression of the tissue factor, the main initiator of blood coagulation, was upregulated in the spleen, lung, and brain of HPAI virus-infected chickens. These results suggest that dysfunction of endothelial cells and monocytes/macrophages upon HPAI virus infection may induce hemostasis abnormalities represented by the excessive blood coagulation and consumptive coagulopathy in chickens.     

The isolation and partial characterization of precursor forms of ostrich carboxypeptidase

Ostrich carboxypeptidases A and B were recently purified and characterized. The aim of this study was to isolate and purify, and partially characterize in terms of molecular weight, pI, amino acid composition and N-terminal sequencing, the precursor forms of carboxypeptidases from the ostrich pancreas. Inhibition studies with soybean trypsin inhibitor and activation studies with three proteases (bovine trypsin, bovine chymotrypsin and porcine elastase) were performed on crude ostrich acetone powder and the carboxypeptidase A and B activities were determined. SDS-PAGE was carried out after every incubation to monitor the rate and degree of conversion of a M(r) 66K component to procarboxypeptidase and carboxypeptidase A and B. The precursor forms were purified by Toyopearl Super Q and Pharmacia Mono Q chromatography. All three proteases converted the M(r) 66K component to procarboxypeptidases and carboxypeptidases over a set time interval, with carboxypeptidase A and B activities being detected in the acetone powder. Chymotrypsin was the preferred protease since it exhibited a more controlled activation of the procarboxypeptidases. The amino acid composition of procarboxypeptidase A revealed 525 residues. The N-terminal sequence of procarboxypeptidase A showed considerable homology when compared with several other mammalian sequences. M(r) and pI values of 52K and 5.23 were obtained for procarboxypeptidase A, respectively. This study indicated that ostrich procarboxypeptidase A is closely related to other mammalian procarboxypeptidase A molecules in terms of physicochemical properties.