Search PubMed⌕ Search

Biomedical subjects

S Ohno

Publications and source records attributed to S Ohno.

At least 937 records · Page 52Linked to original sources
PubMed1981

Testicular feminization of the mouse: paucity of peroxisomes in Leydig cell of the testis.

The testes of mice with the X-linked testicular feminization (Tfm/y hermaphrodite) mutation are very small and cryptorchid. The spermatogenesis in the adult Tfm/y hermaphrodite mouse testes is arrested, and the testosterone biosynthesis is significantly reduced due to deficiency of 17-keto-steroid reductase, the enzyme essential for the conversion of androstanedione to testosterone. In this study the distribution of peroxisomes in the Leydig cells of adult Tfm/y hermaphrodite mice was investigated because of the suggestion that peroxisomes may participate in lipid metabolism and/or androgen biosynthesis is steroidogenic cells. Aldehyde-fixed testicular tissue of Tfm/y hermaphrodite mice was processed for the cytochemical localization of peroxisome catalase to facilitate identification of these organelles in the Leydig cells. Testes from Blo/y and CSa strain normal adult mice served as controls. Testicular Leydig cells of normal adult Blo/y and CSa mice contained abundant smooth endoplasmic reticulum (SER) in the form of complex interconnected tubules and double-walled membranous vesicles. Numerous peroxisomes, often in continuity with SER channels or in close association with lipid droplets, were observed in Leydig cells of normal males. In contrast, the peroxisomes in the Leydig cells of adult Tfm/y hermaphrodite mouse testes were either undiscernible or greatly reduced in number and size. SER in these cells was sparse, whereas mitochondria were numerous. In addition, abundant clusters of lipid droplets were encountered in a majority of Leydig cells of Tfm/y hermaphrodite mouse testes. Peroxisome and SER paucity in Leydig cells of Tfm/y hermaphrodite mice may be a reflection of reduced testosterone production. Whether excessive accumulation of lipid in the Leydig cells of Tfm/y hermaphrodite mouse testes is due to reduced utilization of cholesterol for the biosynthesis of testosterone or to impaired lipid metabolism due to reduction in peroxisome population in these cells remains to be ascertained.

Animals↗
PubMed1981

Delayed skin reactivity of patients with herpetic stromal keratitis.

Twenty-seven patients with chronic stromal keratitis due to herpes simplex virus were tested for delayed skin reactions, to investigate the non-specific immune reactivity in vivo. Skin tests were performed with five ordinary antigens-Candida, mumps, phytohemagglutinin-P (PHA-P), purified protein derivative of tubercle bacillus (PPD), and streptokinase-streptodornase (SK-SD). The reactivity of the patients was generally decreased, as compared to the age-matched 40 healthy controls. Especially, the reactivity of the patients to PHA-P was significantly decreased (p less than 0.007). The largest mean diameters of erythema at 24 or 48 hours in Candida and PHA-P were also significantly less in the patients than in the controls (Candida, p less than 0.02; PHA-P, p less than 0.05).

Adolescent↗
PubMed1980

Cytogenetic studies on abelson-virus-induced mouse leukemias.

The karyotype of Abelson-virus-induced murine leukemias was studied by G-banding. In contrast to the regular trisomy of chromosome 15 in most murine T-cell leukemias, Abelson leukemias were purely diploid, and remained diploid for up to seven consecutive passages in vivo. The hypothesis is advanced that integration into the recipient cell of the DNA copy of the large cellular insert, carried by the Abelson virus, may perform a function similar to the effects of gene duplication by trisomy in the more slowly developing murine leukemias.

Abelson murine leukemia virus↗
PubMed1980

The nucleotide sequence of human fibroblast interferon cDNA.

DNA synthesized by in vitro reverse transcription of the interferon mRNA has been cloned and amplified as recombinant DNA, TpIF319-13 (Taniguchi et al., 1979). The nucleotide sequence of this IF cDNA which consists of 770 bp (excluding the A:T tails) has been determined. The data reported predict the hitherto unknown amino acid sequence of human fibroblast interferon and its putative signal peptide.

Amino Acid Sequence↗
PubMed1980

Studies on the physicochemical structure and stability of an active fragment (T2A) of colicin E3.

The physicochemical nature of an active fragment (T2A) of colicin E3 was examined together with those of its specific inhibitor, B, and the T2A-B complex under various conditions by means of CD and fluorescence spectroscopy. 1. T2A was mainly composed of unordered structure, although the molecule was folded into a rather compact structure, probably by beta-turns and ionic interactions. 2. The structure of T2A was not stable, and unfolding of the molecule was observed on treatments with acid, alkali, heat, guanidine hydrochloride, and detergents. However, once denaturing conditions were removed, the unfolded T2A molecule quickly regained the native conformation, recovering its full activity. 3. Formation of a one-to-one compex of T2A and B was confirmed. No gross conformational changes in T2A and B were found upon formation of the T2A-B complex. 4. A mechanism of dissociation of colicin E3 and A and B, or of T2A-B into T2A and B, during passage through the membrane of colicin E3-infected cells is proposed, based mainly on the results obtained here.

Chemical Phenomena↗
PubMed1980

The effects of carboxypeptidase digestion on the function of colicin E3.

The effects of carboxypeptidase digestion on the function of colcin E3 which had been demonstrated to be a complex of proteins A and B was investigated. It was indicated that removal of 7 amino acids from the C-terminal region of protein A has no significant effect on the interaction with the inhibitor, protein B, or with the specific cell surface receptor but does have an effect on the efficient interaction with the final target, ribosomes.

Amino Acid Sequence↗
PubMed1980

Culture of isolated glomeruli from normal and nephritic rabbits. I. Characterization of outgrowing cells.

The existence of four types of cells in the glomerular outgrowths from both normal and nephritic rabbits was confirmed, and their characteristics by phase contrast, scanning electron, and transmission electron microscopy are described. Type I (arborized), Type II (fusiform), Type III (round), and Type IV (paving stone-like) cells presumably originate from visceral epithelial cells, mesangial cells, monocytes, and parietal epithelial cells of Bowman's capsule, respectively, though conclusive evidence is still lacking. The Type III cells, unlike the other types of cells, have a remarkable phagocytic capacity as well as Fc and C3 receptors.

Animals↗
PubMed1980

Nonrandom chromosomal changes in thy-1-positive and thy-1-negative lymphomas induced by 7,12-dimethylbenzanthracene in SJL mice.

Leukemias were induced by 7,12-dimethylbenzanthracene feeding of intact, thymectomized, or Freund's adjuvant-pretreated SJL mice. Four of six Thy-1-positive thymomas that arose in intact mice had a pseudodiploid stemline with one morphologically similar or identical marker. Banding analysis showed that the marker had arisen by the translocation of the distal part of one chromosome 15 to one X chromosome [t(X;ter 15)]. Two normal No. 15 chromosomes were also present in the same metaphase plates. These four Thy-1-positive lymphomas were thus trisomic for the distal part of chromosome 15. All 8 Thy-1-negative lymphomas, originating in the spleen or lymph nodes of thymectomized or adjuvant-pretreatment mice, had a trisomy of chromosome 12 and also a trisomy of either chromosome 3 or chromosome 18. These results further stress the importance of gene dosage effects, related to the distal part of chromosome 15, in Thy-1-positive T-cell leukemogenesis. The cytogenetic difference between the Thy-1-positive and -negative leukemias supports our hypothesis that nonrandom chromosomal changes in murine leukemias are dependent on the target cell type, rather than the inducing agent.

9,10-Dimethyl-1,2-benzanthracene↗