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Biomedical subjects

J Yamada

Publications and source records attributed to J Yamada.

At least 397 records · Page 22Linked to original sources
PubMed1987

A new polymorphic pepsinogen locus (Pg-2) in the rat (Rattus norvegicus).

Only two types of pepsinogens, which are products of the Pg-1 locus, are present in rat urine. In gastric mucosa, however, additional pepsinogen isozymes are expressed. We have found a polymorphism for rat gastric mucosa pepsinogen using agarose gel electrophoresis. Some inbred rat strains expressed a pepsinogen band, while others did not. The trait was found to be controlled by a single autosomal locus. We tentatively designated the locus as Pg-2 with two alleles, Pg-2a for the one controlling presence of the band and Pg-2o for the one controlling absence. Linkage analysis using BN and TM strains revealed that Pg-2 was closely linked to Pg-1 (3.7 +/- 1.8 cM), and that it did not belong to LG I (Hbb and p), LG II (Acon-1 and Mup-1), LG IV (Hao-1 and Svp-1), LG V (Es-1 and Es-3), LG VI (Gc and h), LG IX (RT1), LG X (Fh and Pep-3), nor a LG containing Ahd-2 (as yet undetermined).

Animals↗
PubMed1986

Chain-shortening of a xenobiotic acyl compound by the peroxisomal beta-oxidation system in rat liver.

When 14C-labeled N-(alpha-methylbenzyl)azelaamic acid (C9), which is an intermediate in the metabolism of N-(alpha-methylbenzyl)linoleamide, a potent hypocholesterolemic agent, was administered to rats, 84% of the radioactivity was recovered in the urine in 24 hr, which contained 66.1% of N-(alpha-methylbenzyl)glutaramic acid (C5) and 8.6% of N-(alpha-methylbenzyl)pimelamic acid (C7) as major metabolites. While 14C-labeled C9 was incubated with isolated hepatocytes, similar metabolites were found, whereas none of the metabolites with an even number of carbon atoms in the acyl side chain was detected. The activity of the chain-shortening of C9 by hepatocytes isolated from clofibrate-treated rats was stimulated to about twice that of untreated hepatocytes, in parallel with the elevation of C9-dependent H2O2-generation. A subcellular fractionation study of the liver revealed that the subcellular distribution of cyanide-insensitive C9-oxidation activity was coincident with that of catalase and of cyanide-insensitive palmitoyl-CoA oxidation. In this reaction, C7 and C5 were produced. For this reaction, the formation of C9-CoA thioester was essential as an intermediary step. These results indicate that peroxisomes are capable of shortening the acyl side-chains of drugs by beta-oxidation and, thus, suggest an additional metabolic role for peroxisomes.

Animals↗
PubMed1986

Immunohistochemical study on the distribution of neuron-specific enolase-and peptide-containing nerves in the reticulorumen and the reticular groove of cattle.

The distribution of nerves containing immunoreactivity for substance P (SP), vasoactive intestinal polypeptide (VIP), leucine-enkephalin (LENK), gastrin-releasing polypeptide (GRP), and somatostatin (SOM) was studied in the reticulorumen and the reticular groove of the calf and cow, use immunohistochemistry. Neuron-specific enolase (NSE) antiserum was used to determine the general distribution of nerves, which was then compared to distribution of immunoreactive (IR) nerves stained for five kinds of peptides. Nerve fibers and cell bodies were observed in all segments examined; however, both elements showed considerable variation in different segments and age groups. The densities of nerve fibers and ganglia were most concentrated in the reticular groove and least numerous in the ruminal wall. VIP-, SP-, and LENK-IR nerves were detected in all segments, whereas GRP- and SOM-IR nerves were detected only in the reticular groove. NSE-IR nerves were moderately abundant in the reticulorumen, but peptide-IR nerves composed only a minor population of nerves with VIP-IR nerves being most abundant. SP-IR nerves were less abundant and LENK-IR nerves were rarely observed. Abundant nerves were detected in the lips of the reticular groove and of these, SP-IR nerves were most abundant, and in order of decreasing abundance, VIP-, LENK-, SOM-, and GRP-IR nerves were observed also. Immunoreactive nerves were more abundant in the calf than in the cow. The reduced abundance of immunoreactive nerves in the cow as compared to calf was striking, particularly with regard to the SP-IR nerves located in the lips of the reticular groove.

Animals↗
PubMed1986

Effects of chlorpromazine and other calmodulin antagonists on phosphatidylcholine-induced vesiculation of platelet plasma membranes.

Dilauroylglycerophosphocholine (C12:0PC)-induced vesiculation of platelet plasma membranes (Kobayashi, T., Okamoto, H., Yamada, J.-I., Setaka, M. and Kwan, T. (1984) Biochim. Biophys. Acta 778, 210-218; Kobayashi, T., Yamada, J.-I., Satoh, N., Setaka, M. and Kwan, T. (1985) Biochim. Biophys. Acta 817, 307-312) was inhibited by chlorpromazine. Preincubation of platelets with chlorpromazine was required for inhibition but incorporation of chlorpromazine into C12:0PC liposomes was not necessary for it, indicating that the observed inhibition of vesiculation was mainly due to the effect of chlorpromazine on platelets and not that on liposomes. The change in platelet membrane fluidity caused by chlorpromazine was not the cause of inhibition of vesiculation. The inhibition of vesiculation by various other calmodulin antagonists was also observed. The inhibitory activities of these calmodulin antagonists and chlorpromazine correspond very well to their abilities to bind to calmodulin. N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) inhibited vesiculation but a structural analogue of it, N-(6-aminohexyl)-1-naphthalenesulfonamide (W-5), had no inhibitory activity. These results suggest the involvement of calmodulin in membrane vesiculation.

Animals↗
PubMed1986

Strain differences in the behaviour induced by tryptamine in five strains of mice.

The effect of intravenous tryptamine on behaviour was investigated in five strains of mice. Tryptamine at 25 mg/kg induced head weaving and hindlimb abduction in all strains of mice. The intensity of these responses correlated significantly with the content of brain tryptamine. Tryptamine also elicited head twitch and this response was unrelated to the content of brain tryptamine.

Animals↗
PubMed1986

Proton transport catalyzed by the sodium pump. Ouabain-sensitive ATPase activity and the phosphorylation of Na,K-ATPase in the absence of sodium ions.

The possibility that H+ might substitute for Na+ at Na+ sites of Na+,K+-ATPase was studied. Na+,K+-ATPase purified from pig kidney showed ouabain-sensitive K+-dependent ATPase activity in the absence of Na+ at acid pH (H+,K+-ATPase). The specific activity was 1.1 mumol Pi/mg/min at pH 5.7, whereas the specific activity of Na+,K+-ATPase was 14 mumol Pi/mg/min at pH 7.5. The enzyme was phosphorylated from ATP in the absence of Na+ at the acid pH. The initial rate of the phosphorylation was also accelerated at the acid pH in the absence of Na+, and the maximal rate obtained at pH 5.5 without Na+ was 9% of the rate at pH 7.0 with Na+. The phosphoenzyme was sensitive to K+ but almost insensitive to ADP. The phosphoenzyme was sensitive to hydroxylamine treatment and the alpha-subunit of the enzyme was found to be phosphorylated. H+,K+-ATPase was inhibited as effectively as Na+,K+-ATPase by N-ethylmaleimide but was less inhibited by oligomycin or dimethyl sulfoxide. These results indicate that protons have an Na+-like effect on the Na+ sites of Na+,K+-ATPase and suggest that protons can be transported by the sodium pump in place of Na+.

Adenosine Triphosphatases↗
PubMed1986

Effect of tryptamine on the behavior of mice.

The effects of tryptamine (TRM) on behavior were investigated in mice. TRM at a dose of 50 mg/kg i.p. induced an inhibition of locomotor activity and, at doses ranging from 150 to 300 mg/kg, induced peculiar behaviors such as head twitch, head weaving, forepaw treading, hindlimb abduction and Straub tail. These behavioral effects were continuous, although TRM rapidly disappeared from the brain. Methysergide, a 5-hydroxytryptamine (5-HT) receptor antagonist, completely abolished TRM-induced excitatory behaviors and p-chlorophenylalanine, a 5-HT depleter, significantly inhibited the behaviors. Our results show that TRM induced both the depression and excitation in the behavior of mice depending on the dosage and TRM-induced excitatory behaviors may be attributed to both its direct stimulation of 5-HT receptors and facilitation of 5-HT release.

Animals↗
PubMed1986

Linkage studies on 13 biochemical loci and 2 coat color loci in a [(BN x TM) x TM] backcross progeny of the rat (Rattus norvegicus).

In a [(BN X TM) X TM] backcross progeny of rats, nine significant linkage associations were found among 105 pairwise combinations of 15 loci. After comparing this with other published data and data of personal communications, we considered that the d gene we tentatively designated may be identical to the gene for pink-eyed dilution (p), and that the associations of Gc-Hbb, RT1-h, and Gc-Fh were due to chance rather than real linkage. The linkages obtained in this study, therefore, were Hbb-p (26.5 +/- 5.5) in LG I, Mup-1-Acon-1 (12.5 +/- 4.1) in LG II, Hao-1-Svp-1 (23.8 +/- 6.6) in LG IV, Es-1-Es-3 (17.2 +/- 4.7) in LG V, h-Gc (10.9 +/- 3.3) in LG VI, and Fh-Pep-3 (32.3 +/- 5.9) in LG X.

Alleles↗
PubMed1986

Effects of sex hormones on congenital kyphosis in Ishibashi rats.

We examined the influence of estrogen and testosterone on the development of congenital kyphosis in Ishibashi rats. Neither hormone caused a growth spurt. Estrogen suppressed the spinal growth and the progression of kyphosis in both sexes, and accelerated narrowing of the epiphyseal plates, which became apparent at 6 weeks after birth in females and 8 weeks in males. In both sexes, maturity of the spine was accelerated and trabeculae were hypertrophied by estrogen. Testosterone suppressed the progression of kyphosis in males, but not in females. Histologically, testosterone had no effects on growth cartilage, but did produce thinning of the bone trabeculae in males.

Animals↗
PubMed1986

[Effect of human recombinant-gamma interferon on the immune function of peripheral blood lymphocytes in cancer patients].

We administered recombinant gamma-interferon (ReIFN-gamma) daily to 7 cancer patients, and the effect on the immune function of peripheral blood lymphocytes was studied. Following the administration of ReIFN-gamma, no characteristic changes were observed in leukocyte count, lymphocyte count, OKT4/OKT8 or Leu 7. Natural killer cell cytotoxicity was augmented in all cases from the first week of administration and retained a high level of activity during the period of treatment. In contrast, the blastogenesis of PBL with PHA decreased from the first week. Suppressor cell activity was augmented from the first week and maintained throughout this period. As to clinical effect, two patients who had metastatic liver tumors showed a response to the administration of ReIFN-gamma.

Aged↗
PubMed1986

Enteroendocrine cells in the developing opossum stomach.

The distribution of enteroendocrine cells showing immunoreactivities to four peptides and one amine was examined in the gastric mucosa of the opossum during postnatal development using specific immunocytochemical methods. Gastrin-, BPP-, glucagon-, somatostatin- and 5-HT-immunoreactive cells were identified in the gastric mucosa of the newborn opossum. Gastrin-immunoreactive cells were restricted to the epithelial lining of the pylorus; glucagon-immunoreactive cells were seen only in the epithelium of the fundus. Somatostatin- and 5-HT-immunoreactive cells were found in the epithelium of both fundic and pyloric regions. BPP-immunoreactive cells were the most numerous endocrine cell type seen in the gastric epithelium of the newborn opossum and although found mainly at the confluence of the fundic and pyloric regions, were confined primarily to the fundus in the one week old opossum and all older animals. A marked increase in all five immunoreactive cell types was seen by the end of the first postnatal week. Gastrin-immunoreactive cells were the most numerous at this time and exceeded adult numbers. Both glucagon- and BPP-immunoreactive cells were confined to the fundic glands of older animals and showed the same pattern of decline with age. Somatostatin- and 5-HT-immunoreactive cells showed a shift in population from the fundus to the pylorus with age and together with gastrin-immunoreactive cells were restricted to a narrow zone at the bottoms of the gastric pits and the upper parts of the pyloric glands.

Animals↗
PubMed1986

Immunohistochemical study of gastroenteropancreatic endocrine cells of the herbivorous Japanese field vole, Microtus montebelli.

The gastroenteropancreatic (GEP) endocrine cells of the Japanese field vole were studied immunohistochemically. Somatostatin-, 5-hydroxytryptamine-, glicentin-, glucagon-, bovine pancreatic polypeptide-, gastrin-, gastric inhibitory polypeptide-, cholecystokinin-, substance P-, secretin-, neurotensin- and insulin-immunoreactive cells were revealed. The characteristic findings of the regional distribution and relative frequency of these immunoreactive cells in the GEP system of the vole were as follows. Somatostatin-immunoreactive cells were more numerous in the oxyntic glands than in the pyloric glands. Some somatostatin-immunoreactive cells were found in small clusters in the oxyntic glands. Gastrin-immunoreactive cells were detected not only in the pyloric glands and small intestine but also in the caecum and spiral colon. Gastric inhibitory polypeptide-immunoreactive cells were also detected in the pyloric glands and no motilin-immunoreactive cell was found in the gastroenteropancreatic system.

Animals↗
PubMed1985

Effect of hypothalamic ventromedial lesions on plasma growth hormone response to growth hormone-releasing factor in rats.

The effect of ventromedial-arcuate (VMH-ARC) nuclei lesions on plasma growth hormone (GH) response to human growth hormone-releasing factor (GRF, 1 microgram/kg b.wt., i.v.) was studied in conscious rats after they had received chlorpromazine (CPZ) or CPZ plus antiserum against somatostatin (ASS). When rats were pretreated with CPZ alone, there was no difference in basal plasma GH level between VMH-ARC lesioned rats and controls. The magnitude of plasma GH response to GRF in 5 out of 6 VMH-ARC lesioned rats exceeded that of controls. When the same observation was repeated using the same rats after they had received ASS and CPZ, basal plasma GH levels of controls were significantly higher than those of VMH-ARC lesioned rats, and the magnitude of the plasma GH response to GRF was augmented in both groups of rats. The plasma GH response to GRF was comparable between two groups, though the peak plasma GH response to GRF was slightly but significantly lower in VMH-ARC lesioned rats as compared to controls. Pituitary GH content was reduced significantly in VMH-ARC lesioned rats as compared to controls. The results demonstrate that the pituitary responsiveness to GRF does not appear to be altered significantly in rats bearing bilateral VMH-ARC lesions. In addition, the placement of electrolytic lesions in VMH-ARC regions causes reduced SS secretion into the hypophyseal portal vessels and leads to an augmentation of plasma GH response to GRF.

Animals↗