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Biomedical subjects

J Yamada

Publications and source records attributed to J Yamada.

At least 271 records · Page 15Linked to original sources
PubMed1992

Spinal cord cells innervating the bilateral parabrachial nuclei in the rat. A retrograde fluorescent double-labeling study.

The internal lateral nucleus (IL) of the parabrachial nucleus receives information from the spinal cord. The IL perhaps relays nociceptive signals to the intralaminar nuclei of the thalamus, apparently being implicated in the motivational-affective component of pain reactions. However, cells of origin of spinal fibers to the IL have not been investigated enough. We intended to clarify these cells, as well as their shapes, by retrograde double-labeling techniques. Fast blue and diamidino yellow dyes were injected, respectively, into the left and right ILs. The distribution of double-labeled cells was almost the same as that of single-labeled cells on both sides of the spinal cord. The total number of bilateral double-labeled cells was highest in the dorsolateral part of the lateral funiculus (DL), followed, in order, by lamina I, the dorsomedial part of the lateral funiculus (DM), lamina V and lamina VII. A few double-labeled cells were seen in laminae II-IV, VI, VIII and X. The ratio of the total number of bilateral double-labeled cells to the total number of bilateral single-labeled cells through the spinal cord was 43% in the DL, 37% in the DM, 28% in lamina V and 24% in lamina I. The ratio was 10% or less in the other remaining laminae. No marked differences were observed between the shapes of double- and single-labeled cells.

Amidines↗
PubMed1992

A single serine:pyruvate aminotransferase gene on rat chromosome 9q34-q36.

It was found in our previous study (Oda et al., 1990. J. Biol. Chem. 265: 7513-7519) that in the rat two mRNAs encoding mitochondrial and peroxisomal serine:pyruvate aminotransferase (SPT/AGT) are formed from a single SPT/AGT gene through alternative transcription initiation in exon 1. In an attempt to analyze the mechanisms underlying this unique phenomenon, we have isolated genomic clones harboring the entire rat SPT/AGT gene. In the present study, the location of the rat SPT/AGT gene was determined to be in the q34-q36 region of chromosome 9 by fluorescence in situ hybridization. Southern blot analysis of rat genomic DNA revealed an allelic BamHI restriction fragment length polymorphism among three different inbred rat strains. These results indicated that a single copy SPT/AGT gene is located on chromosome 9q34-q36 in the rat genome. This locus has been assigned the gene symbol Spat.

Animals↗
PubMed1992

Chromosomal assignments of 17 structural genes and 11 related DNA fragments in rats (Rattus norvegicus) by Southern blot analysis of rat x mouse somatic cell hybrid clones.

DNA from 18 rat x mouse somatic cell hybrid clones, which segregated individual rat chromosomes, was analyzed by Southern blot for chromosomal gene assignments. Through the use of 17 DNA probes cloned from 7 rat genes, A2M, ATP1A1, ATP1A2, ATP1A3, B2M, GSTP, and SMST; 5 mouse genes, Ncam, Ngfg, Pim-1, Tcp-1, and Trp53; and 5 human genes, MBP, MYB, NEFM, SCN2A, and TCRGC1, 17 structural genes including 15 newly assigned genes and 11 related DNA fragments were assigned to particular rat chromosomes. Syntenic conservation of the genes among rats, mice, and humans is discussed.

Animals↗
PubMed1992

Loss of peroxisomal enzyme expression in preneoplastic and neoplastic lesions induced by peroxisome proliferators in rat livers.

Immunohistochemical staining of enoyl CoA hydratase (ECH), a key peroxisomal enzyme, revealed that the putative preneoplastic lesions induced in livers by administration of the peroxisome proliferator (PP) clofibrate (0.3% in diet) to rats for 60 weeks or more, lacked this enzyme so that they could be detected as ECH-negative foci. ECH and other peroxisomal enzymes such as acyl CoA oxidase, catalase and carnitine-dependent acetyltransferase were also either not or only weakly expressed in most hepatic hyperplastic nodules and hepatomas induced by ciprofibrate (0.025% in diet), Wy-14,643 (0.1%) or BR-931 (0.2%), while being strongly induced in surrounding hepatocytes. These results indicate that the expression of ECH and other peroxisomal enzymes is repressed in putative preneoplastic and neoplastic lesions induced by PPs in rat livers and that these peroxisomal enzymes might therefore be used as negative markers.

Animals↗
PubMed1992

Rat gene mapping using PCR-analyzed microsatellites.

One hundred and seventy-four rat loci which contain short tandem repeat sequences were extracted from the GenBank or EMBL data bases and used to define primers for amplification by the polymerase chain reaction (PCR) of the microsatellite regions, creating PCR-formatted sequence-tagged microsatellite sites (STMSs). One hundred and thirty-four STMSs for 118 loci, including 6 randomly cloned STMSs, were characterized: (i) PCR-analyzed loci were assigned to specific chromosomes using a panel of rat x mouse somatic cell hybrid clones. (ii) Length variation of the STMSs among 8 inbred rat strains could be visualized at 85 of 107 loci examined (79.4%). (iii) A genetic map, integrating biochemical, coat color, mutant and restriction fragment length polymorphism loci, was constructed based on the segregation of 125 polymorphic markers in seven rat backcrosses and in two F2 crosses. Twenty four linkage groups were identified, all of which were assigned to a defined chromosome. As a reflection of the bias for coding sequences in the public data bases, the STMSs described herein are often associated with genes. Hence, the genetic map we report coincides with a gene map. The corresponding map locations of the homologous mouse and human genes are also listed for comparative mapping purposes.

Animals↗
PubMed1992

Alterations of benzodiazepine receptor binding in tremor rats with absence-like seizures.

Tremor rats begin to exhibit clinical or electrical absence-like seizures after 6 weeks of age, and by 14 weeks of age, all have seizures. Central-type benzodiazepine receptor binding was investigated in tremor rats and control rats, aged 4 weeks and 16 weeks. Significantly lower benzodiazepine receptor density and no differences in affinity were found in the hippocampus of the tremor rats in comparison with that of control rats at both ages. This abnormality is considered to be due to a tremor gene and may be the cause of absence-like seizures in tremor rats. A significantly lower receptor density was found in the cerebellum at 4 weeks of age in the tremor rats than in the control rats. These changes may be related to tremorous movements in the tremor rats. Receptor density was significantly lower in the brainstems of tremor rats and control rats at 16 weeks of age than at 4 weeks of age, and the decrease was more marked in control rats. These facts may reflect a reduced decrease in the response to the dysfunction of gamma-aminobutyric acidergic neurons, or the function of the gamma-aminobutyric acid/benzodiazepine receptor system may be secondarily increased to suppress seizures in 16-week-old tremor rats.

Animals↗
PubMed1992

Study on stereospecificity of enzyme reaction related to peroxisomal bile acid synthesis in rat liver.

We examined stereoselectivities of enzymes related to bile acid formation in hepatic peroxisomes using two stereoisomers of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid (THCA) and its coenzyme A (CoA) derivatives. The activity of acyl-CoA synthetase for 25 S-THCA was 1.4-times higher than that for 25 R-THCA. The difference was also observed after clofibrate-treatment. This activity was located in microsomes, differing from palmitoyl-CoA synthetase located in mitochondria, peroxisomes and microsomes. There was no stereoselectivity in the reaction of peroxisomal fatty acyl-CoA oxidase for THCA isomers, and the activity was one tenth of that for acyl-CoA synthetase. Considering the overall reaction of peroxisomal bile acid formation, the stereoselective difference observed in THCA-CoA synthesis should be denied. Thus, the previous finding that the overall formation of bile acid from THCA was not stereoselective was further confirmed. Furthermore, the activity for THCA oxidation was not induced by clofibric acid, suggesting that there would be different isozymes of peroxisomal acyl-CoA oxidase against THCA-CoA and palmitoyl-CoA.

Acyl-CoA Oxidase↗
PubMed1992

The effects of the serotonin1A receptor agonist buspirone on the blood glucose and pancreatic hormones in rats.

The effects of the serotonin1A (5-HT1A) receptor agonist buspirone on the plasma glucose and pancreatic hormones insulin and glucagon were investigated in rats. Buspirone elicited significant hyperglycemia and hyperglucagonemia, although it did not affect the insulin levels. Adrenodemedullation inhibited both the increase in blood glucose and glucagon levels. These results indicate that buspirone-induced hyperglycemia and hyperglucagonemia are mediated by adrenaline release from the adrenal gland.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1992

Morphological study on the stomach of the lesser mouse deer (Tragulus javanicus) with special reference to the internal surface.

The stomach of the lesser mouse deer (Tragulus javanicus) was observed macroscopically. It consisted of only three compartments, rumen, reticulum and abomasum without omasum. The rumen was S-shaped with large ventral and caudoventral blind sacs and the reticulum was larger than the abomasum. Internally, the rumen was covered with numerous ruminal papillae even on the pillars and the ruminoreticular fold. These papillae were leaf- or tongue-like shaped and varied in size and density. The reticulum had honey-combed crests and the secondary crests were found rarely. The lips of the reticular groove were prominent and more developed in the aboral part than in the oral one. A sac-like transition zone, which had more prominent mucosal folds than had the floor of the reticular groove, was observed between the caudal end of the reticular groove and the abomasum. Mucosal folds of the abomasum were spiral, low but rather thick. These findings were discussed in view of comparison with other ruminants and of possible functional implications.

Animals↗
PubMed1992

An immunohistochemical study on the pancreatic endocrine cells of the three-toed sloth, Bradypus variegatus.

The cellular composition and relative frequency of the occurrence of pancreatic endocrine cells were studied immunohistochemically in a primitive eutherian and arboreal folivore, the three-toed sloth, since previous histochemical and ultrastructural studies on the endocrine pancreas of the sloth have detected only a single islet cell type, the A cell. In the sloth pancreas, four types of endocrine cells immunoreactive for glucagon, insulin, somatostatin and serotonin (5-hydroxytryptamine) were found as reported in the pancreas of human and common experimental mammals, but pancreatic polypeptide-immunoreactive cells were not detected by either avian- or bovine-pancreatic polypeptide antiserum. The endocrine cells were distributed mainly in the islets and partly also in the exocrine tissue including the pancreatic ducts. Larger or smaller clusters consisting of glucagon- and insulin-immunoreactive cells were also found frequently in the interlobular connective tissue. In the islets, glucagon- and insulin-immunoreactive cells were the most prominent cell type, while somatostatin- and serotonin-immunoreactive cells were sparse. The most striking feature in the sloth pancreas is the high frequency of glucagon-immunoreactive cells, because these cells are by far less in number than insulin-immunoreactive cells in the islets of human and common experimental mammals. This appears to be an intriguing characteristic of the sloth pancreas in a possible relation to the animal's unique metabolic system and the phylogenetical position.

Animals↗
PubMed1992

Psoriasis-associated periodontitis: a case report.

Psoriasis with oral manifestations is rarely seen. It has been reported in the past either as an oral manifestation of this skin disease or lichen planus accompanying psoriasis. Very few periodontal lesions associated with dermatologic psoriasis have been reported in the literature. This report describes a case of psoriasis in which exacerbation of the cutaneous disease was accompanied by gingival epithelial changes and periodontal bursts, together with a report on the light microscopy of biopsies from periodontal lesions.

Adult↗