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Biomedical subjects

J Yamada

Publications and source records attributed to J Yamada.

At least 343 records · Page 19Linked to original sources
PubMed1990

[Serotonin and tryptamine metabolism in the acute hepatic failure model--changes in tryptophan and its metabolites in the liver, brain, kidney and serum].

When trinitrophenylated (TNP) hepatocytes and lipopolysaccharide (LPS) are intravenously injected into TNP-liver protein sensitized guinea pigs, massive hepatic cell necrosis was induced in most of mice. Using this experimental acute hepatic failure model, the tryptophan metabolism in the liver, brain, kidney and serum was studied. As a result, the tryptophan level was remarkably high in all three organs and serum, and the metabolism of both the tryptamine pathway and serotonin pathway was induced. Also, in the brain, the tryptamine metabolism was more induced compared to the serotonin. These results suggest that the metabolites of tryptophan may be involved in this acute hepatic failure model.

Acute Disease↗
PubMed1989

Nerve stimulation does not necessarily enhance retrograde HRP labeling of rat motoneuron.

The retrograde horseradish peroxidase (HRP) labeling of medial gastrocnemius (MG) motoneurons was not enhanced by electrical stimulation of the sciatic nerve after HRP injection into the MG muscle of the rat. When pulse trains with short intermissions were applied immediately after the HRP injection, the number of labeled MG motoneurons on the stimulated side was even smaller than that on the control side.

Animals↗
PubMed1989

Axon collaterals of spinocerebellar fibers terminate in the parabrachial nucleus of the rat.

When horseradish peroxidase (HRP) or wheat germ agglutinin conjugated with HRP was injected into the anterior cerebellar vermis or the spinal cord segments in the rat, terminal labeling was seen in the small round area within the dorsal part of the middle one-third of the parabrachial nucleus (PB). When the tracer was injected into the round PB area, many neuronal cell bodies were labeled in the spinal cord segments, but none in the cerebellum. Thus, the terminal labeling in the round PB area was assumed to be that of axon collaterals of spinocerebellar fibers.

Animals↗
PubMed1989

The effects of blocking nerve conduction on retrograde HRP labeling of rat motoneuron.

The effect of blocking nerve conduction on retrograde horseradish peroxidase (HRP) labeling was investigated for rat hindlimb motoneurons. Conduction of the sciatic nerve in the left leg was blocked with tetrodotoxin, and HRP solution was injected into the medial gastrocnemius (MG) muscles of both sides. The total number of labeled MG motoneurons and the labeling intensities of individual cell somas were measured. There were no differences in these two parameters between the blocked and the intact sides. The results suggest that motoneurons are sufficiently well labeled with HRP, even if they are electrically silent.

Animals↗
PubMed1989

Compartmentation of dicarboxylic acid beta-oxidation in rat liver: importance of peroxisomes in the metabolism of dicarboxylic acids.

Peroxisomal and mitochondrial beta-oxidation of dicarboxylic acids (DCAs) were investigated and compared. When isolated hepatocytes were incubated with DCAs of various chain lengths, H2O2 was derived from peroxisomal beta-oxidation, the rates of its generation being comparable to those seen with monocarboxylic acids (MCAs), whereas the rates of ketone body production, a measure of mitochondrial beta-oxidation, were much lower than those with MCAs. Peroxisomal beta-oxidation measured by cyanide-insensitive NAD reduction exhibited similar chain-length specificities for both dicarboxylyl-CoAs (DC-CoAs) and monocarboxylyl-CoAs (MC-CoAs), except that the activities for DC-CoAs with 10-16 carbon atoms were about half of those of the corresponding MC-CoAs. In contrast, mitochondrial beta-oxidation measured by antimycin A-sensitive O2 consumption had no activity for DCAs. In the study with purified enzymes, the reactivities of mitochondrial carnitine palmitoyltransferase and acyl-CoA dehydrogenase for DC-CoAs were much lower than those for MC-CoAs, while the reactivity of peroxisomal acyl-CoA oxidase for DC-CoAs was comparable to that for the corresponding MC-CoAs. Accordingly, the properties of carnitine palmitoyltransferase and acyl-CoA dehydrogenase must be the rate-limiting factors for mitochondrial beta-oxidation, with the result that DCAs might hardly be oxidized in mitochondria. Comparative study of beta-oxidation capacities of peroxisomes and mitochondria in the liver showed that DC12-CoA was hardly subjected to mitochondrial beta-oxidation, and that the beta-oxidation of DCAs in rat liver, therefore, must be carried out exclusively in peroxisomes.

Acyl-CoA Dehydrogenases↗
PubMed1989

Species differences in the effects of bezafibrate, a hypolipidemic agent, on hepatic peroxisome-associated enzymes.

The effects of bezafibrate on hepatic peroxisome-associated enzymes of rats, mice, guinea pigs, hamsters, rabbits, dogs and monkeys were examined. Dogs and monkeys were given bezafibrate orally at 30 mg/kg body wt daily for 2 weeks and at 125 mg/kg body wt daily for 13 weeks, respectively, and other species at 100 mg/kg daily for 2 weeks. In male rats, marked changes were observed in the activities of catalase (1.73-fold), D-amino acid oxidase (DAAO; 0.56-fold), fatty acyl-CoA oxidizing system (FAOS; 12.9-fold) and carnitine acetyltransferase (CAT; 35.8-fold); in female rats, the changes were less than in the males. In mice, there were no apparent sex differences in the responses of hepatic peroxisomal enzymes to bezafibrate and the increases in the activities of catalase, FAOS and CAT were 1.76-, 3.75- and 7.94-fold respectively. In guinea pigs, only slight increases in the activities of FAOS (3.00-fold) and CAT (2.83-fold) were observed. In hamsters, the increases in catalase, FAOS and CAT activities, were 1.23-, 2.19- and 2.77-fold respectively. Although rabbits and dogs showed slight increases in CAT activity, no significant response to the drug was observed in monkeys. Hepatomegaly and the increase of hepatic content of peroxisome proliferation-associated polypeptide (PPA-80), which has been recognized as a peroxisomal bifunctional protein in the fatty acid beta-oxidation pathway, were observed only in rats and mice. These results show that there were marked species differences in the effects of bezafibrate on hepatic peroxisomes, and that bezafibrate induced hepatic peroxisome proliferation in rodents, especially rats and mice.

Animals↗
PubMed1989

Serotonin-induced hypoglycemia and increased serum insulin levels in mice.

The effects of serotonin (5-HT) on plasma glucose levels were studied. 5-HT above 20 mg/kg induced apparent hypoglycemia in mice. The hypoglycemic effects of 5-HT were strongly antagonized by methysergide but only partially inhibited by ketanserin. However, ICS 205-930 was without effect. This indicates that the hypoglycemia induced by 5-HT is mediated by both the 5-HT1 and 5-HT2 receptors. 5-HT also produced an increase in serum immunoreactive insulin (IRI) which was completely inhibited by methysergide and partially antagonized by ketanserin. It is suggested that the 5-HT-induced increase in IRI is elicited by the activation of the 5-HT1 and 5-HT2 receptors, which is similar to the results obtained with plasma glucose. These results indicate that the 5-HT receptors may regulate blood glucose levels by modifying the release of insulin.

Animals↗
PubMed1989

Purification of a Brucella canis cell wall antigen by using immunosorbent columns and use of the antigen in enzyme-linked immunosorbent assay for specific diagnosis of canine brucellosis.

A cell wall antigen of Brucella canis was purified by immunosorbent columns. The antigen contained two proteins of 30 and 28 kilodaltons and a polysaccharide exhibiting a 12-kilodalton band upon 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antibody to the purified antigen, which specifically reacted with the polysaccharide, was used as the first coating antibody in an enzyme-linked immunosorbent assay (ELISA) for serological diagnosis of canine brucellosis. Dogs inoculated orally with live B. canis were positive and dogs from B. canis-free colonies were negative in the ELISA. Of 199 dogs from a brucellosis-contaminated area, 116 with negative titers in the tube agglutination test (TAT), using heat-inactivated whole B. canis cells as the antigen, were also negative in the ELISA. Seventy-eight of the dogs with questionable titers in the TAT were divided into two groups: 20 dogs that were positive in the ELISA and 58 that were negative. Of five dogs with positive titers in the TAT, three were positive in the ELISA and the gel immunodiffusion test (GD) with crude B. canis extract as the antigen and were also culture positive for B. canis. One dog was positive in the ELISA and GD but gave a negative culture result. Serum from the remaining dog, which was positive with high titer in the TAT but negative in the ELISA and in culture for B. canis, formed a spur precipitate with a homologous precipitate in the GD. These results indicate that the ELISA is a specific serological test for B. canis infection in dogs.

Agglutination Tests↗
PubMed1989

Spinocerebellar tract neurons with axons passing through the inferior or superior cerebellar peduncles. A retrograde horseradish peroxidase study in rats.

Using the retrograde horseradish peroxidase (HRP) method, we determined whether axons of the spinocerebellar tract (SCT) neurons pass through the superior (SCP) or the inferior (ICP) cerebellar peduncle in rats. Following bilateral section of either the SCPs or the ICPs, HRP was injected into the cerebellar anterior lobe and lobule VI, and the resulting labeled neurons were quantitatively examined throughout the length of the spinal cord. Almost all SCT neurons in the central cervical nucleus, Clarke's column and lamina VII of the third cervical (C3) to third thoracic (T3) segments and the T11 to fifth lumbar (L5) segments, and the majority of SCT neurons in the ventrolateral part of the anterior horn of the L6 to caudal (Ca) segments and laminae V of the C8-L5 segments and VII of the L6-Ca segments project their axons through the ICPs. The majority of spinal border cells (T11-L5) and a large number of SCT neurons in lamina VII of the C3-T3, T11-L5 and L6-Ca segments project their axons through the SCPs. A nearly equal number of SCT neurons in lamina VIII (C1-L6) send axons through the SCPs or the ICPs. The proportion of SCT neurons projecting via the SCPs versus those projecting via the ICPs was approximately 1:5.

Animals↗
PubMed1989

Restriction fragment length polymorphisms of the angiotensinogen gene in inbred rat strains and mapping of the gene on chromosome 19q.

Using a cDNA probe of the rat angiotensinogen gene (ANG), restriction fragment length polymorphisms (RFLPs) were detected in inbred rat strains with the restriction enzymes HindIII, PstI, and PvuII. Three alleles of ANG were almost equally distributed in 11 inbred strains. In two sets of backcross progeny originating from parental strains with different alleles, no close linkage was found between the ANG locus and 17 other loci tested. In situ hybridization, however, allowed assignment of the gene to chromosome 19q. The RFLPs of the angiotensinogen gene, therefore, can be considered useful as markers of rat chromosome 19.

Alleles↗
PubMed1989

Immunohistochemical study of the developing endocrine pancreas of the opossum (Didelphis virginiana).

Cells immunoreactive for insulin, glucagon, somatostatin, bovine pancreatic polypeptide and 5-hydroxytryptamine are found in the pancreas of the newborn opossum and of all later stages examined. All immunoreactive cell types are present in primary and secondary islets and within elements of the exocrine pancreas. Cells immunoreactive for glucagon, bovine pancreatic polypeptide, somatostatin and 5-hydroxytryptamine generally are confined to the periphery of secondary (intralobular) islets, whereas insulin-immunoreactive cells occupy the central region. Endocrine cells within primary (interlobular) islets are randomly scattered. A small number of pancreatic-polypeptide-immunoreactive cells are reactive for the amine 5-hydroxytryptamine also, but the reverse is not observed. The endocrine pancreas continues to differentiate and develop throughout postnatal life and into adulthood. Little difference was observed between the head and tail regions of the opossum pancreas for the measurements made.

Aging↗
PubMed1989

The evidence for the involvement of the 5-HT1A receptor in 5-HT syndrome induced in mice by tryptamine.

The involvement of the 5-HT1A receptor in the 5-HT syndrome (head weaving and hindlimb abduction) induced in DBA mice by tryptamine was investigated. Methysergide, (-)propranolol and spiperone suppressed both the head weaving and hindlimb abduction induced by tryptamine. However, ketanserin and ICS 205-930 did not affect them. Haloperidol induced small decreases in the head weaving, but had no effect on the hindlimb abduction. These results indicate that the 5-HT syndrome induced by tryptamine in mice is mediated by the 5-HT1A receptor. Therefore, 5-HT syndrome may also be associated with the 5-HT1A receptor in mice, as it is in rats.

Animals↗
PubMed1989

Second genetic polymorphism of tear proteins in the rat (Rtp-2).

Electrophoresis of tear proteins on agarose gel showed polymorphism in the fastest migrating protein among 32 inbred strains of rats. In 8 strains, the protein was missing (RTP-2 B), while the other strains expressed the protein (RTP-2 A). The trait was found to be controlled by a single autosomal locus. The designation Rtp-2 locus, with two alleles (Rtp-2a, Rtp-2b), is tentatively proposed. The Rtp-2 locus is loosely linked to c locus, with a recombination frequency of 36.7 +/- 5.4 percent.

Animals↗
PubMed1989

An immunohistochemical study on the distribution of endocrine cells in the gastrointestinal tract of domestic pigeon, (Columba livia var domestica).

The endocrine cells in the gastrointestinal tract of the domestic pigeon (Columba livia var domestica) were studied immunohistochemically, and their distribution and relative frequencies were determined. In the proventriculus, moderate numbers of somatostatin- and numerous gastrin-releasing polypeptide (GRP)-immunoreactive cells were found. No immunoreactive cells were detected in the gizzard. In the pyloric region, many motilin-immunoreactive cells were found in addition to numerous somatostatin- and gastrin-immunoreactive cells. In the intestine, somatostatin-, gastrin-, serotonin-, neurotensin-, pancreatic glucagon- and enteroglucagon-immunoreactive cells were found to have in differing distribution patterns.

Animals↗
PubMed1989

An immunohistochemical study on the distribution of endocrine cells in the chicken gastrointestinal tract.

The distribution and the frequency of occurrence of nine types of gut endocrine cells were revealed using immunohistochemical methods in eight portions from the gastrointestinal tract of the chicken (Gallus gallus var domestica). In the proventriculus, somatostatin- and gastrin-releasing polypeptide (GRP)-immunoreactive cells were commonly found. Serotonin-, pancreatic glucagon-, and enteroglucagon-immunoreactive cells were uncommon. Avian pancreatic polypeptide (APP)-immunoreactive cells were rare. In the gizzard, numerous GRP-, and a small number of somatostatin-immunoreactive cells were observed. The pyloric region was characterized by the presence of abundant gastrin-, somatostatin-, and neurotensin-immunoreactive cells. Numerous serotonin-immunoreactive cells were detected in all portions of the intestine. Moderate numbers of neurotensin-immunoreactive cells were detected in all portions of the intestine except for the cecum. A few gastrin- and somatostatin-immunoreactive cells were detected in the duodenum and jejunum. A small number of pancreatic glucagon-immunoreactive cells were detected in the jejunum and ileum. Enteroglucagon-immunoreactive cells were detected in the small intestine in increasing numbers forwards the ileum. Motilin-immunoreactive cells were rare in the small intestine.

Animals↗
PubMed1989

An immunohistochemical study of gastrointestinal endocrine cells in a nectarivorous marsupial, the honey possum (Tarsipes rostratus).

The distribution and relative frequency of occurrence of gastrointestinal endocrine cells exhibiting immunoreactivity to eleven peptides and one amine were examined immunohistochemically in the gastrointestinal mucosa of the adult honey possum which feeds almost exclusively on nectar and pollen. Seven types of endocrine cells, immunoreactive for serotonin, somatostatin, gastrin, motilin, enteroglucagon, neurotensin and gastric inhibitory peptide (GIP), were detected in the gastrointestinal mucosa of the honey possum. In the cardiac gland region, including the diverticulum, endocrine cells were very scarce, and few serotonin- and somatostatin-immunoreactive cells were identified in 4 out of 8 honey possums. Moderate numbers of serotonin- and a few somatostatin-immunoreactive cells were found in the fundic glands. In the pyloric glands, moderate numbers of gastrin-immunoreactive cells and a few serotonin- and somatostatin-immunoreactive cells were detected. Along the length of the small intestine, serotonin-immunoreactive cells were the dominant endocrine cell type but small numbers of somatostatin-, gastrin-, motilin-, enteroglucagon-, neurotensin- and GIP-immunoreactive cells, all with different distribution patterns and relative frequencies of occurrences, were also found. In the large intestine, a small number of serotonin- and enteroglucagon-immunoreactive cells were found in all animals, but a few somatostatin- and neurotensin-immunoreactive cells were detected in some animals.

Animals↗
PubMed1989

Enteroendocrine cells in the developing opossum small intestine and colon.

Enteroendocrine cells immunoreactive for gastrin, bovine pancreatic polypeptide (BPP), glucagon (glicentin), 5-hydroxytryptamine (5-HT), somatostatin, secretin, motilin, gastric inhibitory peptide (GIP) and cholecystokinin (CCK) are scattered throughout the small intestinal epithelium of the newborn opossum and in all later postnatal stages examined. The number of BPP- and glucagon-immunoreactive cells is relatively high in the newborn and rapidly decreases until only occasional cells are present after the first postnatal week. Cells immunoreactive for GIP, CCK, 5-HT, motilin, gastrin and secretin increase in number with development. Secretin-, motilin-, CCK- and GIP-immunoreactive cells generally are concentrated proximally in the small intestine and as they increase in number, differentiate in more distal regions. The number of gastrin-immunoreactive cells actually decreases just prior to weaning but then increases at and after, weaning. Neurotensin-immunoreactive cells are unusual in that they do not appear until about the 74th postnatal day and then are first encountered in the distal small intestine. As development progresses they increase in number and appear in the more proximal regions. Cells immunoreactive for 5-HT at first increase but then decrease sharply at weaning only to increase markedly again after this time. In contrast, somatostatin-immunoreactive cells gradually decrease in number until weaning then dramatically increase. If the total number of enteroendocrine cells in the small intestine is considered, there is a gradual decrease from birth until weaning when a dramatic increase occurs. Cells immunoreactive for neurotensin, 5-HT and somatostatin are also found in the intestinal epithelium of the developing colon and caecum. Somatostatin- and 5-HT-immunoreactive cells are found throughout the colon in the newborn whereas neurotensin-immunoreactive cells, although observed initially in the proximal colon, do not form a significant population until weaning and then are concentrated distally.

Animals↗