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Biomedical subjects

Y Kitamura

Publications and source records attributed to Y Kitamura.

At least 793 records · Page 44Linked to original sources
PubMed1980

The effects of steel mutation on testicular germ cell differentiation.

The effects of artificial cryptorchidism and its surgical reversal on spermatogenesis were examined in germ cell mutant, S1/+ and wild type, +/+, mice. In cryptorchid testes no difference was found between S1/+ and +/+ mice in the number of undifferentiated type A spermatogonia. The activity of type A spermatogonia in mutant mice appeared normal as judged by its mitotic cell number and DNA synthesis. The surgical reversal of cryptorchidism resulted in regenerative differentiation of mature germ cells in both types of mice, but the pattern of cellular differentiation in the mutant testes was completely different from that of the wild type testes. At two steps of cellular differentiation, intermediate or type B spermatogonia and spermatid, the numbers of cells were much smaller in the S1/+ testes than those in the +/+ testes. The steel gene was therefore suggested to exert its effects on the differentiation of type A spermatogonia to intermediate or type B spermatogonia, on meiotic division and/or the survival rate of these cells, but not on the undifferentiated type A spermatogonia or stem cells.

Animals↗
PubMed1980

Effect of oxidized oil on lipogenic enzymes.

Male Wistar rats were fed for 4 wk on diets containing 2% oxidized corn oil. Liver tissue was then studied to determine the effect of feeding peroxidized oil on lipogenic enzymes. Although substances which reacted with thiobarbituric acid increased in liver microsomes and mitochondria with increasing peroxide values of the dietary corn oil fed, the activities of glucose-6-phosphate dehydrogenase, malic enzyme and acetyl-CoA carboxylase in liver were unchanged. However, when rats were fed for 2 wk on diets containing 10% fat, of which 0.5, 5 or 10% was unoxidized corn oil and the remainder was hydrogenated beef tallow filler, the lipogenic enzyme activities and also the liver triglyceride levels were observed to decrease with increasing amounts of dietary corn oil. Therefore, although a synthetic diet containing corn oil was easy to oxidize spontaneously, the reductions of lipogenic enzymes in rats fed the diet would not have been caused by lipid peroxides but by unsaturated fatty acids themselves.

Acetyl-CoA Carboxylase↗
PubMed1980

Structure of slow-reacting substance of anaphylaxis (SRS-A).

To elucidate the chemical structure of slow-reacting substance of anaphylaxis from rat (SRS-A rat), SRS-A rat were purified by the method of Orange with modification using DEAE-Sephadex A-25 chromatography. Ultraviolet absorption spectrum of purified SRS-A rat indicated the presence of conjugated triene. Arylsulfatase B degradation products and HCl degradation products were subjected to analysis by a gas chromatography and mass spectrometry and a thin layer chromatography. Products obtained by arylsulfatase b catalysis contained 5,6-dihydroxy-7,9,11,14-eicosatetraenoic acid. HCl degradation products showed the presence of glycine, glutamic acid and cysteic acid. Furthermore, the analysis of anhydrous hydrazine degradation products of SRS-A rat and of HCl hydrolyzed products of dinitrophenylated SRS-A rat revealed the presence of glycine at C-terminal and glutamine acid at N-terminal. The study of the substrate specificity of arylsulfatase B against various materials including SRS-A rat suggested the presence of sulfone in SRS-A rat. The molecular ion peak of SRS-A rat sodium salt was observed at m/e 680 in field desorption mass spectrum of SRS-A rat. On the basis of these data, we identified the structure of SRS-A rat as [gamma]glutamyl-4(5-hydroxy-7,9,11,14-eicosatetraenoic acid-6-yl)-4,4-dioxyocysteinyl] glycine.

Animals↗
PubMed1980

Effect of corn oil feeding on lipid peroxidation in rats.

Three groups of male rats were maintained on 10% fat diets containing 0.5, 5 or 10% corn oil or olive oil with 80--400 mg DL-alpha-tocopherol per kilogram. After 4 weeks on such regimens, TBA (thiobarbituric acid) values in serum, liver mitochondria and microsomes, and adipose tissue increased with rising amounts of dietary corn oil. TBA values in rats fed the 10% corn oil diet were reduced with the increase of dietary tocopherol but were still higher than the corresponding values of the 10% olive oil and 0.5% corn oil groups. When the liver microsomes were incubated with Fe3+-ADP and NADPH, the relative chemiluminescence emission in the visible region with the peroxidative cleavage of endogenous lipid was higher in the 5 and 10% corn oil groups than in the 0.5% group. On the other hand, when oxidized corn oil was given orally to rats with thoracic lymph fistula, TBA-reacting substances were recovered in thoracic lymph, but iodometric peroxide was undetectable. Therefore, TBA-reacting substances in rats fed the corn oil diets could have originated from the oxidative product of linoleic acid metabolism and also from the diet.

Adipose Tissue↗
PubMed1980

pH-dependent adhesion of piliated Corynebacterium renale to bovine bladder epithelial cells.

The adhesion of Corynebacterium renale 115 to bovine bladder epithelial cells was studied with two clones of the bacteria, piliated (P+) and nonpiliated (P-). The percentage of the cells with attached P+ bacteria was greater than that of the cells with attached P- bacteria, and the number of attached P+ bacteria was higher than that of the P- bacteria. The adhesion of P+ bacteria was found to be pH dependent, which was supported by the following facts: the number of attached bacteria was high at a pH above 7.6 and low at a pH below 6.8; the adhering P+ bacteria were eluted immediately after the pH was decreased from 7.4 to 6.4; and the P+ bacteria unattached at pH 6.4 adhered to the cells immediately after the pH was increased to pH 7.4. The adhesion of P+ bacteria was inhibited by anti-pilus antiserum. The adhesion was not inhibited by amino acids or sugars, including mannose, and was not influenced by Ca2+ and Mg2+. P- bacteria hardly attached to the epithelial cells, irrespective of the pH and other factors.

Amino Acids↗
PubMed1980

Reference sample microsphere method: cardiac output and blood flows in conscious rat.

Validation of the reference sample method (RSM) in the rat was accomplished by: 1) simultaneous measurement of cardiac output (CO) by the RSM and electromagnetic flowmetry method in ether-anesthetized open-chest Wistar rats, and 2) determination of systemic and regional hemodynamic reproducibility in conscious rats following three serial injections of microspheres. The optimal sampling time and sampling rate were determined in several CO states. The results indicate that: 1) 200 or more microspheres contained in the reference sample result in an accurate determination of CO, 2) almost 100% of the microspheres are trapped by tissues with in 20 s of cessation of the microsphere injection, 3) the hemodynamic steady state is affected only under low cardiac output conditions at a high sampling rate (1.211 ml/min), 4) three repeated injections of microspheres in conscious animals do not alter systemic hemodynamis, and 5) the reproducibility of regional blood flow distribution is good in all organs except the liver, stomach, spleen, and skin (third application). These data indicate that the RSM is reliable, providing reasonable accuracy and reproducibility of systemic and regional hemodynamics in the rat.

Animals↗
PubMed1980

Coincidental development of forestomach papilloma and prepyloric ulcer in nontreated mutant mice of W/Wv and SI/SId genotypes.

A double gene dose of mutant alleles at either the W or Sl locus produces the pleiotropic effects of anemia, sterility, lack of hair pigmentation, and lack of tissue mast cells. Coincidental development of forestomach papilloma and prepyloric ulcer was observed in about 40% of nontreated (WB X C57BL/6) F1-W/Wv mice raised in our laboratory. The stomach lesions of the W/Wv mice could be detected at the 15th day after birth, and such lesions never appeared in the W/+, Wv/+, and +/+ littermates maintained under the same laboratory conditions. Since the stomach lesions were also observed in (WC X C57BL/6) F1-Sl/Sld mice purchased from The Jackson Laboratory, phenotypes common to both W/Wv and Sl/Sld mice seem to play an essential role in the spontaneous development of the forestomach papilloma and prepyloric ulcer.

Anemia↗
PubMed1980

[Pharmacological properties of trapidil: comparison with other coronary vasodilators (author's transl)].

Effects of trapidil and other coronary vasodilators on retrograde blood flow in acute coronary-ligated dogs, isolated large and small coronary arteries of pig, platelet aggregation, biosynthesis of prostacyclin in isolated aortic rings and hyperlipemia in quails were investigated. Trapidil showed an increase in retrograde blood flow while dipyridamole, nifedipine, diltiazem and dilazep did not. Trapidil and nitroglycerin relaxed large coronary arteries, while dipyridamole, diltiazem, dilazep and adenosine relaxed small arteries. Trapidil, dipyridamole, diltiazem and aspirin protected against the secondary phase of ADP-induced platelet aggregation in guinea-pig platelet rich plasma more effectively than did nifedipine and dilazep. Trapidil and aspirin protected only against rabbit platelet aggregation as induced by arachidonic acid. Moreover, only trapidil protected against platelet aggregation as induced by prostaglandin G2-thromboxane A2 mixture. Trapidil and dipyridamole enhanced the platelet aggregation protection of prostacyclin. Trapidil also facilitated biosynthesis of prostacyclin more markedly than did the other drugs. Trapidil increased serum content of HDL cholesterol and significantly lowered serum content of triglyceride and the ratio of LDL cholesterol to HDL cholesterol in hyperlipemic quails. Dipyridamole, diltiazem, nifedipine and dilazep, however, showed little effect.

Animals↗
PubMed1980

Effect of androgen depletion on postoperative regrowth of androgen-dependent and -independent Shionogi carcinomas in mice.

About 350 castrated male DS mice given testosterone propionate (TP, 100 micrograms/mouse/day) were grafted with androgen-dependent SC115 tumor or androgen-independent tumors (NHD with positive receptor; NHF with negative receptor). After 20 or 15 days, most of the developed tumors were excised and the mice were divided into 3 groups. TP injection was continued in one group and TP was stopped immediately or 20 days after the excision in the other groups. The cumulative 120-day mortality after transplantation of SC115 tumor into mice was significantly lower in the immediate androgen removal group (10%, 6/59) than in the androgen-injected group (59%, 51/87) or the delayed androgen removal group (42%, 19/45). The cumulative mortalities in mice with androgen-independent NHD and NHF tumors in the immediate androgen removal groups (97 and 91%, respectively) were similar to those in the androgen-injected groups (90 and 95%, respectively). All non-operated and TP-injected mice grafted with SC115 and androgen-independent tumor died due to the tumors within 50 and within 30 days after the transplantation, respectively. These findings suggest the usefulness of adjuvant endocrine therapy for preventing the recurrence of hormone-dependent tumors.

Androgens↗
PubMed1980

Effect of serial passage in female nude athymic mice on androgen dependency of Shionogi carcinoma 115.

When Shionogi carcinoma 115 (SC115, an undifferentiated medullary carcinoma showing a compact cell pattern and containing androgen receptor) was transplanted into male and female DS mice, it grew only in males. In contrast with this strict androgen dependency in DS hosts, SC115 tumors grew in male and female nude athymic (BALB/c-nu/nu) mice. Although most of the tumors developing in female nude mice were composed of spindle-shaped cells and did not contain androgen receptor, about 5% of tumors in female nude mice retained morphological and biochemical characteristics of the original SC115 tumor. Such a tumor was serially transplanted in female nude mice. Although no significant changes were detectable in histological and chromosomal features and in androgen receptor values, the growth speed in female nude mice accelerated and became comparable to the growth speed of the original SC115 tumor in intact male DS mice. However, this subline of SC115 tumor showed a marked androgen dependency when reinoculated into male and female DS mice after 14 passages in female mice nude mice in spite of its relative androgen independency in nude hosts. Therefore, the present results seem to suggest that the immunological status of the hosts may affect the hormone dependency of tumors.

Androgens↗
PubMed1979

Distribution of mast-cell precursors in hematopoeitic and lymphopoietic tissues of mice.

Two experimental systems were used to investigate the origin of precursor cells which differentiate into tissue mast cells in vivo. (a) Increase of mast cell number was examined in the skin, stomach, cecum, and mesentery of genetically mast cell-depleted WBB6F1 (WB X C57BL/6)-W/WV mice after the injection of various hematolymphoid cells of congenic +/+ mice. (b) Appearance of mast cells with giant granules was studied in irradiated C57BL/6-+/+ mice after the injection of lymphoid cells of C57BL/6-bgJ/bgJ (beige, Chediak-Higashi syndrome) mice. Concentrations of mast cell precursors in the thymus, lymph node and Peyer's patch were less than 0.1% of the concentration in the bone marrow. Neither treatment of donor bone marrow cells with anti-Thy-1.2 serum and complement nor thymectomy of the recipient mice affects the development of mast cells in the skin, stomach, cecum, and mesentery. Moreover, the number of mast cells increased to normal level when the skin of WBB6F1-W/WV mice was grafted on the back of nude athymic (BALB/c-nu/nu) mice. These results indicate that mast cell precursors are derived from hematopoietic tissues rather than lymphopoetic ones and that the differentiation of the precursor cells does not depend on T lymphocytes or the thymus.

Animals↗