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Biomedical subjects

K Omori

Publications and source records attributed to K Omori.

At least 217 records · Page 12Linked to original sources
PubMed1981

Purification and characterization of four components of rat caseins.

Rat casein components (C1-, C3A-, C3B- and C4-casein) were extensively purified from rat milk, and the properties of these proteins were compared with those of other caseins including rat C2-casein. C1-casein was precipitated by a low concentration of CaCl2 (1.5 mM). Both C3A- and C3B-casein were less sensitive to Ca2+ than were C1- and C2-casein, and the presence of 20 mM CaCl2 was required at 37 degrees C for their precipitation. C4-casein was absolutely insensitive to Ca2+. This protein exhibited the ability to stabilize all of the other rat casein components against Ca2+-dependent precipitation. In addition, C4-casein contained sialic acid, galactose and N-acetylgalactosamine. Therefore, C4-casein appears to be a bovine kappa-casein-like protein.

Amino Acids↗
PubMed1981

Purification and properties of a major casein component of rat milk.

A casein component (C2-casein) was purified by ion-exchange and gel filtration chromatography from rat milk, and the properties of this protein were examined. The molecular weight of C2-casein, as determined by Sepharose 4B gel filtration in 6 M guanidine hydrochloride, was 34 000 +/- 1000. The average hydrophobicity calculated from the amino acid composition showed that C2-casein is a rather hydrophilic protein. The alpha-helix content obtained from optical rotatory dispersion experiments was about 12%. In ultracentrifugation analyses, monomer and polymer peaks of C2-casein were both seen, and the monomer-to-polymer ratio was not affected by changing temperature conditions. C2-casein was precipitated by the presence of 2.5 mM CaCl2, and the precipitability was greatly decreased by the dephosphorylation of the protein. C2-casein was stabilized from Ca2+-dependent precipitation by the addition of another rat casein component (C3-casein) or of bovine kappa-casein.

Amino Acids↗
PubMed1981

Partial characterization of RNA polymerase II complex released by micrococcal nuclease digestion of rat liver nuclei.

Two forms of RNA polymerase II were released from rat liver chromatin by micrococcal nuclease digestion of the nuclei. One from behaved like a free RNA polymerase II and the other like a complex with other nuclear components. Both forms of RNA polymerase II activity were recovered in the 0.16 M NaCl-soluble fraction of the nuclear digest, and the complexed from the RNA polymerase II could transcribe its endogenous template under conditions permitting only of elongation of the RNA synthesis. The RNA polymerase II complex was further purified by gel filtration chromatography and column electrophoresis. Analysis of protein and DNA of the partially purified complex suggested that the RNA polymerase II was bound to mono- or dinucleosomes carrying some characteristic nonhistone proteins. Furthermore, in experiments on tissues from starved rats, the two forms of RNA polymerase II were found to originate from different functional states of the chromatin-bound enzyme in vivo.

Animals↗
PubMed1981

Distribution and induction of cytochrome P-450 in rat liver nuclear envelope.

Induction of cytochrome P-450s by 3-methylcholanthrene (MC) and phenobarbital (PB) and distribution of P-450s in the rat liver nuclear envelope were investigated by biochemical analyses and ferritin immunoelectron microscopy using specific antibodies against the major molecular species of MC- and PB-induced cytochrome P-450. It was found, in agreement with Kasper (J. Biol. Chem., 1971, 246: 577-581), that the total amount of cytochrome P-450s determined by biochemical analysis was markedly increased by MC, but not by PB, treatment. Immunoelectron microscopic analysis, however, showed marked and slight increases in ferritin labeling by MC and PB treatment, respectively. The latter finding was interpreted as resulting from the induction of a particular molecular species of PB-induced cytochrome P-450s. Ferritin immunoelectron microscopic analysis of intact isolated nuclei, naked nuclei from which the outer membrane of the nuclear envelope was partially detached (mechanically), and isolated nuclear envelopes have shown that the ferritin particles are found exclusively on the cytoplasmic face of the outer nuclear envelopes. Neither the nucleoplasmic face of the inner membrane of the nuclear envelope nor the cisternal face of both membranes of the nuclear envelope showed any labeling with ferritin. This indicates that cytochrome P-450 is located only on the outer membrane of the nuclear envelope and does not diffuse laterally into the domain of the inner membrane of the nuclear envelope across the nuclear pores. Our results suggest that a marked heterogeneity exists in the enzyme distribution between the outer and inner membrane of the nuclear envelope and that microsomal marker enzymes such as cytochrome P-450 exist exclusively in the outer membrane. In addition, it appears that cytochrome P-450 is probably not a transmembrane protein but an intrinsic protein located on the cytoplasmic face of the outer membrane of the nuclear envelope.

Animals↗
PubMed1981

Plasma thromboxane B2 levels and atherosclerotic disorders.

In our ongoing studies of the interrelationship between platelets and the vascular wall we found that an accurate estimate could be made of the clinical condition and more effective therapy prescribed when we monitored alterations in the plasma levels of TXB2. For this purpose we devised a radioimmunoassay with I125-TXB2-Tyramide. Patients with ischemic heart disorders, cerebral apoplexy, diabetes mellitus, Buerger's disease, Takayasu disease etc., all had statistically high levels of TXB2 as compared with healthy controls. In particular, patients with myocardial infarction, cerebral thrombosis and/or hemorrhage all revealed increases in levels of TXB2 and these levels increased in parallel with a worsening of the clinical condition, and there was always a re-increase in TXB2 level before a recurrence of an attack. As plasma TXB2 levels clearly reflect thrombogenic disorders, the assessment of these levels on a routine basis, enables a more accurate diagnosis, an indication of possible recurrences, and more effective chemotherapy and rehabilitation.

Adolescent↗
PubMed1979

[Suprasternal bone (author's transl)].

Human skeletons have many variations which may occasionally necessitate distinction from pathologic changes. Suprasternal bone is an unfamiliar normal variation in the vicinity of the sternoclavicular joint. It was first described by Béclard in 1820 and thereafter many reports have appeared, mostly in anatomy and embryology. An incidence less than 5% is reported abroad. This report describes the incidence of suprasternal bone in Japanese and a few clinical reference cases. Suprasternal bone is now considered to have derived from the persistent rudiment of epicoracoid which should have normally consisted of the part of manubrium sterni. Suprasternal tubercle is considered to be the osseously fused type of suprasternal bone. The material consisted of two groups: 1) Seventy-four sterna were examined roentgenographically which were removed en bloc from the cadavera. 2) 562 sterna of living subjects were examined roentgenographically by Kattan's method. In the seventy-four cadavera, eight cases had suprasternal bones (10.8%) and fourteen cases had suprasternal tubercles. Among them, three had suprasternal bone and tubercle on each side. In the 562 living subjects, thirty-nine cases had suprasternal bones (6.9%) and eight cases had suprasternal tubercles. Among them, three had both on each side. The incidence of suprasternal bone in Japanese is therefore higher than foreigners' reported previously. Kattan's method employed in this study is simple and excellent to show manubrium sterni and sternoclavicular joint clearly. It is emphasized that suprasternal bone is not uncommon and differential diagnosis from pathologic changes is easy as long as it is kept in mind.

Adult↗