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Biomedical subjects

Y Tamada

Publications and source records attributed to Y Tamada.

At least 19 recordsLinked to original sources
PubMed1996

Selective increase in astrocytic elements in the rat dentate gyrus after chronic toluene exposure studied by GFAP immunocytochemistry and electron microscopy.

Using glial fibrillary acidic protein (GFAP) immunohistochemistry, and electron microscopy, we examined changes in the features of astrocytes in the dentate gyrus of the hippocampal formation after high-dose chronic toluene inhalation (2000 ppm, 4 h/day) for 1 month. In toluene-treated rats, the numbers of GFAP-immunoreactive (IR) astrocytes were not changed, whereas the area and intensity of GFAP-IR processes were increased markedly in the dentate gyrus. In addition, dense, thick and highly-stained GFAP-IR processes appeared entering into the granular cell layer, compared with those of controls. At the electron microscopic level, numerous astrocytic processes with high electron density intervened between the granular cells. These results suggest that high-dose of chronic toluene exposure induces morphological changes in astrocytes in the dentate gyrus of the hippocampal formation.

Administration, Inhalation↗
PubMed1996

Relationship of human liver dihydrodiol dehydrogenases to hepatic bile-acid-binding protein and an oxidoreductase of human colon cells.

We previously isolated three monomeric dihydrodiol dehydrogenases, DD1, DD2 and DD4, from human liver, and cloned a cDNA (C9) thought to encode DD2, which is identical with those for human bile-acid-binding protein and an oxidoreductase of human colon carcinoma HT29 cells. In the present study we have provided evidence that the C9 cDNA clone encodes DD1, not DD2. A recombinant enzyme expressed from the cDNA in a bacterial system was purified, and its catalytic properties, bile-acid-binding ability and primary sequence were compared with those of the hepatic dihydrodiol dehydrogenases. The results show that DD1 encoded by C9 possesses prostaglandin F synthase activity but low affinity for lithocholic acid, whereas DD2, showing differences of six amino acid residues from the DD1 sequence, exhibited high-affinity binding for the bile acid. Refined relationship between dihydrodiol dehydrogenases and their related proteins of human tissues is proposed.

Amino Acid Sequence↗
PubMed1996

Activation of human liver 3 alpha-hydroxysteroid dehydrogenase by sulphobromophthalein.

Human liver contains at least two isoenzymes (DD2 and DD4) of 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase. The NADP(H)-linked oxidoreductase activities of DD4 were activated more than 4-fold by sulphobromophthalein at concentrations above 20 microM and under physiological pH conditions. Sulphobromophthalein did not stimulate the activities of DD2 and human liver aldehyde reductase, which are functionally and/or structurally related to DD4. No stimulatory effect on the activity of DD4 was observed with other organic anions such as Indocyanine Green, haematin and Rose Bengal. The binding of sulphobromophthalein to DD4 was instantaneous and reversible, and was detected by fluorescence and ultrafiltration assays. The activation by sulphobromophthalein decreased the activation energy in the dehydrogenation reaction for the enzyme, and increased both kcat, and Km values for the coenzymes and substrates. Kinetic analyses with respect to concentrations of NADP+ and (S)-(+)-indan-1-ol indicated that sulphobromophthalein was a non-essential activator of mixed type showing a dissociation constant of 2.6 microM. Thus, the human 3 alpha-hydroxysteroid dehydrogenase isoenzyme has a binding site specific to sulphobromophthalein, and the hepatic metabolism mediated by this isoenzyme may be influenced when this drug is administered.

3-Hydroxysteroid Dehydrogenases↗
PubMed1996

Apoptotic cell death in formation of vesicular skin lesions in patients with acquired zinc deficiency.

We investigated the role of apoptotic cell death in the production of skin lesions in patients with acquired zinc deficiency. Nuclear condensation of keratinocytes was observed at an early stage of skin lesions in patients with zinc deficiency, especially around vesicular lesions. Nuclei of keratinocytes in perivesicular lesions of the epidermis were positively stained by the nick-end labeling specific for fragmented DNA. Lewis Y antigen was also expressed on perivesicular lesions. On the other hand, there were no such positively stained cells in hyperkeratotic skin lesions of the patients. Therefore, it was suggested that apoptotic cell death might play a role in the formation of vesicular skin lesions in patients with zinc deficiency, but not in the formation of hyperkeratotic skin lesions.

Adult↗
PubMed1996

Apoptotic cell death in the response of D-galactosamine-sensitized mice to lipopolysaccharide as an experimental endotoxic shock model.

The apoptotic cell death induced in D-galactosamine-sensitized mice by administration of lipopolysaccharide was characterized. Administration of lipopolysaccharide caused apoptotic cell death in livers of D-galactosamine-sensitized mice. Apoptotic cells were also detected in the kidney, thymus, spleen, and lymph node. Severe hepatic apoptosis in D-galactosamine-sensitized mice was reproduced by transfer of the sera from mice injected with D-galactosamine and lipopolysaccharide. The hepatocyte apoptosis induced by lipopolysaccharide was completely prevented by an anti-tumor necrosis factor alpha antibody but not by an anti-gamma interferon antibody. Administration of recombinant tumor necrosis factor into D-galactosamine-sensitized mice also caused hepatocyte apoptosis. Lipopolysaccharide-induced hepatocyte apoptosis in D-galactosamine-sensitized mice did not seem to be mediated by Fas antigen. It was suggested that lipopolysaccharide- induced hepatic injury and failure in D-galactosamine-sensitized mice was due to the apoptotic cell death of hepatocytes caused by tumor necrosis factor alpha released in the circulation.

Animals↗
PubMed1996

Expression of heat shock protein 72 on peripheral blood mononuclear cells from patients with pustulosis palmaris et plantaris.

The expression of heat shock protein (HSP) 72 on peripheral blood mononuclear cells (PBMC) from patients with pustulosis palmaris et plantaris (PPP) was studied. PBMC isolated freshly from patients with PPP expressed HSP72, while those from psoriasis patients did not. PBMC from patients with PPP continued to express it in in vitro cultures at 37 degrees C. This expression was further augmented by in vitro heat stimulation at 43 degrees C. Immunofluorescence studies showed that approximately 20% of PBMC from patients with PPP were stained positively with anti-HSP72 antibody. HSP72 was expressed on both nonadherent and adherent cells of PBMC. These findings suggest that PBMC from patients with PPP may produce HSP72 spontaneously through their in vivo exposure to stressful agents.

Adult↗
PubMed1996

Role of adhesion molecules in the development of pustular lesions in patients with pustulosis palmaris et plantaris.

The expression of adhesion molecules and the ligands on endothelial cells and infiltrating inflammatory cells in lesional skin specimens from patients with pustulosis palmaris et plantaris was studied. Intercellular adhesion molecule-1 and E-selectin were expressed on endothelial cells of microvessels in the papillary dermis. Intercellular adhesion molecule-1 was also expressed focally on keratinocytes in the epidermis of the lesional skin. On the other hand, lymphocyte function-associated antigen-1, Mac-1 and sialyl Lewis(x) were expressed on infiltrating inflammatory cells. Further, flow cytometric analysis demonstrated that circulating leukocytes in peripheral blood from patients with pustulosis palmaris et plantaris expressed the ligands of adhesion molecules. It is therefore suggested that the expression of adhesion molecules and the ligands on circulating leukocytes, endothelial cells, infiltrating inflammatory cells and keratinocytes might be closely related to the formation of pustular lesions in patients with pustulosis palmaris et plantaris.

Adult↗
PubMed1996

Increasing coronary perfusion pressure on diastolic and systolic performance is less pronounced in right ventricle than in left ventricle.

OBJECTIVE: Little is known as to whether an increase in coronary perfusion pressure can alter the right ventricular (RV) distensibility and the contractile function as it does in the case of the LV. METHODS: In eight isolated isovolumically contracting canine hearts, RV and LV volumes and coronary perfusion were independently controlled. Effects of an increase in coronary perfusion pressure (from 73 +/- 1 to 152 +/- 6 mmHg) on the end-diastolic and end-systolic pressure-volume relations in both RV and LV were assessed. RESULTS: Following an increase in coronary perfusion, and at a similar volume of the ventricles, end-diastolic pressure was elevated by 2.8 +/- 0.8 mmHg in RV and 8.9 +/- 2.0 mmHg in LV (P < 0.01; RV vs LV), and the slope of RV end-systolic pressure-volume relation, Ees, increased by 11 +/- 6% (P < 0.05) and that of the LV Ees by 21 +/- 5% (P < 0.01). The percent change of RV pressure-volume area (PVA) was less than that in LV-PVA (26 +/- 9 vs 48 +/- 11%; P < 0.05). CONCLUSIONS: Accordingly, increases in coronary perfusion pressure and/or flow decreased the RV distensibility and enhanced the RV contractile function, the extent of which, however, was less than that in the LV.

Animals↗
PubMed1995

Simple method for platelet counting.

A method is proposed for counting the number of adhered platelets based on the determination of lactate dehydrogenase activity in bulk after lysis of adhered platelets. This method was compared with the widely used radioisotope labelling technique. It was concluded that the present lactate dehydrogenase method is effective in counting the adhered platelets, as no significant difference was found between the readings of two methods when commercial polymers and glass were used as samples.

Biocompatible Materials↗
PubMed1995

Circadian change of VIP mRNA in the rat suprachiasmatic nucleus following p-chlorophenylalanine (PCPA) treatment in constant darkness.

Neuronal activity of the suprachiasmatic nucleus (SCN) is known to be regulated by two major extrinsic factors conveyed by three anatomically distinct pathways to the SCN: photic stimulus by the direct retinohypothalamic tract (RHT) and the indirect geniculohypothalamic tract (GHT), and information from the brainstem by ascending forebrain serotonergic (5-hydroxytryptamine: 5-HT) tract. It has been shown that VIP mRNA level in neurons of the SCN is altered by external light, but remains stable in constant darkness. In the present study, by using the in situ hybridization technique combined with computer-assisted image analysis, we examined VIP mRNA expression in the SCN of rats in which the two major factors were eliminated, i.e. photic stimulus by exposing animals in total darkness and 5-HT transmission by three-day successive administration of p-chlorophenyl-alanine methylester (an inhibitor of tryptophan hydroxylase, 200 mg/kg, daily). In saline-treated controls, VIP mRNA levels remained almost constant throughout the day. In contrast, in PCPA-treated rats, a significant rhythm of VIP mRNA was observed with a peak at CT 4 and a trough at CT 20. These observations suggest that the removal of photic and 5-HT influence induces VIP mRNA rhythm in the SCN, indicating that VIP mRNA is controlled not only by photic information but also by the circadian clock.

Analysis of Variance↗
PubMed1995

Lichen planus pemphigoides: identification of 180 kd hemidesmosome antigen.

We describe a man with lichen planus pemphigoides. Direct immunofluorescence studies of peribullous skin showed linear deposition of IgG and C3 in the basement membrane zone. Indirect immunofluorescence studies disclosed circulating anti-basement membrane zone antibodies. Immunoelectron microscopy demonstrated binding of antibodies to the hemidesmosomes and lamina lucida. The patient's serum defined only the minor bullous pemphigoid antigen with a molecular weight of 180 kd. These findings suggest the coexistence of lichen planus and bullous pemphigoid in lichen planus pemphigoides.

Aged↗
PubMed1995

Expression and kinetic properties of a recombinant 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase isoenzyme of human liver.

Human liver cytosol contains multiple forms of 3 alpha-hydroxysteroid dehydrogenase and dihydrodiol dehydrogenase with hydroxysteroid dehydrogenase activity, and multiple cDNAs for the enzymes have been cloned from human liver cDNA libraries. To understand the relationship of the multiple enzyme froms to the genes, a cDNA, which has been reported to code for an isoenzyme of human liver 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase, was expressed in Escherichia coli. The recombinant enzyme showed structural and functional properties almost identical to those of the isoenzyme purified from human liver. In addition, the recombinant isoenzyme efficiently reduced 5 alpha-dihydrotestosterone and 5 beta-dihydrocortisone, the known substrates of human liver 3 alpha-hydroxysteroid dehydrogenase and chlordecone reductase previously purified, which suggests that these human liver enzymes are identical. Furthermore, the steady-state kinetic data for NADP(+)-linked (S)-1-indanol oxidation by the recombinant isoenzyme were consistent with a sequential ordered mechanism in which NADP+ binds first. Phenolphthalein inhibited this isoenzyme much more potently than it did the other human liver dihydrodiol dehydrogenases, and was a competitive inhibitor (Ki = 20 nM) that bound to the enzyme-NADP+ complex.

3-Hydroxysteroid Dehydrogenases↗
PubMed1995

Pemphigoid nodularis: a case with 230 kDa hemidesmosomes antigen associated with bullous pemphigoid antigen.

We report a 73-year-old woman with typical clinical, histological and immunofluorescence features of pemphigoid nodularis. Direct immunofluorescence studies of prurigo nodularis-like lesions and peribullous skin showed the linear deposition of IgG and C3 at the basement membrane zone. Circulating IgG against the basement membrane was also detected by indirect immunofluorescence. The serum from the patient was shown to contain the autoantibody against 230 kDa hemidesmosomal antigen associated with bullous pemphigoid antigen.

Aged↗
PubMed1995

Expression of Lewis Y (Le(y)) antigen in human anagen hair follicles.

Lewis Y (Le(y)) antigen, a difucosylated tetrasaccharide found on type 2 blood group oligosaccharides of glycolipids and glycoproteins, is thought to be a phenotypic marker predictive of cell differentiation. The distribution of this antigen in human anagen hair follicles was examined by immunohistochemical staining using a monoclonal antibody (AH-6) to Le(y). In the bulbar and suprabulbar portion of anagen hair follicles, Le(y) antigen was detected in the three layers of the inner root sheath. Subsequently, the positive staining became translocated to the innermost layer of the outer root sheath in the middle part of the hair follicles. In the upper portion of the hair follicles, Le(y) antigen was found in the outer cells of the outer root sheath. These findings suggested that the expression of Le(y) antigen in the anagen hair follicles was correlated with the processes of keratinization or terminal differentiation.

Antibodies, Monoclonal↗
PubMed1995

Over-expression of pig lung carbonyl reductase in Escherichia coli.

Tetrameric carbonyl reductase of pig lung has been shown by cDNA cloning to be a member of the short-chain dehydrogenase family of enzymes. Construction of the carbonyl reductase cDNA in an expression vector yielded an abundant, enzymatically active enzyme in Escherichia coli. The recombinant enzyme was purified to homogeneity and shown to be structurally, immunologically and functionally similar to lung carbonyl reductase.

Alcohol Oxidoreductases↗
PubMed1995

Expression of transglutaminase I in human anagen hair follicles.

The expression of the transglutaminase I in human anagen hair follicles was studied by an immunohistochemical staining. In the bulbar and suprabulbar portions of anagen hair follicles, transglutaminase I was detected on the hair cuticle and the three layers of the inner root sheath. Subsequently, the positive staining became translocated to the inner site of the outer root sheath in the middle part of the hair follicle. In the upper portion of the hair follicle transglutaminase I was detected in the internal part of the outer root sheath and the surface epidermis. Therefore, it was suggested that the expression of transglutaminase I might be closely associated with the terminal keratinization in the anagen hair follicles.

Adult↗
PubMed1994

Pituitary adenylate cyclase-activating polypeptide (PACAP)-like immunoreactive neuronal elements in rat hypothalamus and median eminence with special reference to morphological background of its effect on anterior pituitary--light and electron microscopic immunocytochemistry.

Pituitary adenylate cyclase-activating polypeptide-like immunoreactive (PACAP-LI) neuronal elements in the rat hypothalamus including the median eminence (ME) were investigated by light and electron microscopic immunocytochemistry. PACAP-LI neuronal perikarya with well-developed cell organelles and dense granules were distributed mainly in the magnocellualr portion of the paraventricular nucleus and throughout the entire supraoptic nucleus. In the ME, numerous PACAP-LI neuronal processes were found in the internal layer (IL), and immunoreactive terminals containing dense granules, vesicles and mitochondria were detected around portal capillaries which penetrated into the IL from the external layer. Thereafter, PACAP is released into the portal capillaries in the IL, transported to the anterior pituitary and plays a role in the stimulation of adenylate cyclase of anterior pituitary cells.

Adenylyl Cyclases↗