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Biomedical subjects

Y Tamada

Publications and source records attributed to Y Tamada.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1994

Serotonin depletion by p-chlorophenylalanine decreases VIP mRNA in the suprachiasmatic nucleus.

The influence of serotonergic inputs on the levels of vasoactive intestinal peptide (VIP) mRNA in the rat suprachiasmatic nucleus (SCN) was examined by in situ hybridization combined with morphometrical analysis. Depletion of serotonin by p-chlorophenylalanine methyl ester (300 mg/kg i.p. daily for 3 days) caused a marked decrease in VIP mRNA signal levels in the ventrolateral part of the SCN. This finding suggests that serotonergic input controls VIP production at the mRNA level.

Animals↗
PubMed1994

Fibroblast growth on polymer surfaces and biosynthesis of collagen.

The growth and morphology of rat fibroblasts cultured on various polymer substrates, as well as their collagen biosynthesis, were studied. A clear difference in cell growth and cell morphology was observed among the substrates. The dependence of cell growth on the water contact angle of substrate was similar to that of the adhesion. Fibroblasts could proliferate at the highest rate and showed the highest-ordered morphology when cultured on the substrate with a contact angle around 70 degrees, which was also the most favorable for cell adhesion. The amount of collagen synthesized by total cells and of adsorption of the synthesized collagen to substrates were in good correlation with the cell growth dependence on the contact angle of substrate, whereas the collagen synthesis per cell was more active on the surfaces poor for cell growth than on the good ones. Cells on surfaces promoting active collagen synthesis had a round shape and clustered upon each other. The collagen-immobilized surface had nearly the highest cell adhesion, high cell proliferation, and high collagen adsorption among the substrates studied. In addition, the highest-ordered morphology and no lag time for proliferation were observed for the collagen-immobilized surface. These results indicate that the collagen-immobilized substrate provides the most favorable surface for cell growth at the initial stage.

Animals↗
PubMed1994

Catecholaminergic input to spinally projecting serotonin neurons in the rostral ventromedial medulla oblongata of the rat.

The midline of the rostral ventral medulla (RVM) is the portion in which many serotonin (5-HT) neurons of the nucleus raphe magnus and the rostral nucleus raphe pallidus are located and where dense catecholaminergic (CA) fibers are distributed. In this study, we investigated the connection between spinally projecting 5-HT neurons and CA fibers in the rat RVM by light and electron microscopic immunocytochemistry. First, light microscopic immunocytochemistry using a triple labeling method revealed that the 5-HT-immunoreactive (IR) neuron containing retrograde tracer from the cervical cord was intimately surrounded by tyrosine hydroxylase (TH)-IR fibers. Second, silver-gold intensified TH-IR axon terminals were found to make synaptic contacts with 5-HT-IR neuronal perikarya and dendrites by double labeling immunoelectron microscopy. These morphological findings suggest that spinally projecting 5-HT neurons, presumed to be involved in pain modulation or sympathetic autonomic control, are directly regulated by CA neurons at the level of the RVM.

Animals↗
PubMed1994

Identification of programmed cell death in normal human skin tissues by using specific labelling of fragmented DNA.

Programmed cell death (PCD) in normal human skin tissues was studied by using in situ specific labelling of fragmented DNA. This labelling method clearly stained the nuclei of Henle's layer in the bulb of the anagen hair follicle in serial sections, and the nuclei of the inner root sheath cuticle cells and Huxley's layer cells showed positive staining in the upper part of the hair follicles. This staining pattern was consistent with the sequence of keratinization in the three layers. The nuclei of differentiated cells located at the centre of the sebaceous glands, and those of the granular keratinocyte layer, were also stained. These findings suggest that PCD might play a key role in the terminal differentiation of the epidermis and epidermal appendages.

Apoptosis↗
PubMed1993

Virulence-associated plasmids in Rhodococcus equi.

Twenty-three strains of Rhodococcus equi from independent clinical cases were analyzed for the presence of virulence plasmid DNA. Of the clinical isolates, 19 contained an 85-kb plasmid and the remaining 4 contained a 90-kb plasmid. All of the isolates expressed 15- to 17-kDa antigens and were virulent in mice. Restriction enzyme and Southern blot analyses showed large regions of DNA homology between the 85- and 90-kb virulence plasmids. It was concluded tentatively that there are at least two virulence plasmids in R. equi and that they have a common origin.

AIDS-Related Opportunistic Infections↗
PubMed1993

Resetting of regional preload due to ventricular shape change alters diastolic and systolic performance.

The diastolic and systolic pressure of one ventricle is increased by an increase in volume and/or pressure of the opposite ventricle; however, a mechanism for the ventricular interaction remains unclear. We hypothesized that the shape change of one ventricle elicited by the opposite ventricle would lead to resetting of the regional length, which may explain the ventricular interaction. We used 15 cross-circulated isovolumically contracting canine hearts in which both ventricular volumes were independently controlled. Diastolic regional segment area was calculated by multiplying circumferential and longitudinal lengths on right ventricular free wall (RVFW; n = 6), interventricular septum (IVS; n = 11), and left ventricular (LV) FW (n = 12). The regional area at relatively small volumes of both ventricles were expressed as 100%. With constant RV volume, increasing LV from 7 to 19 ml increased RV diastolic and systolic pressures by 2.7 and 5.5 mmHg, respectively. Conversely, increasing RV volume increased LV diastolic and systolic pressures by 2.3 and 7.5 mmHg, respectively. Increasing LV volume increased RVFW regional area from 121.0 to 124.6% (P < 0.01) and increased IVS regional area from 103.3 to 108.7% (P < 0.01), whereas the RV volume was held constant. Increasing RV volume also increased LVFW and IVS regional areas from 109.9 to 111.6% (P < 0.01) and from 106.8 to 108.9% (P < 0.05), respectively. Ventricular shape change elicited by ventricular interaction will increase the regional wall area, even though the volume of the chamber is unchanged. The increase in the regional area alters the position of the tissue on its resting and active length-tension relations and, thus, leads to enhancement of the chamber pressure.

Animals↗
PubMed1993

[The biological activities of the human papillomavirus type 16 E6/E7 cDNAs cloned from the SiHa cervical carcinoma cell line].

Both the spliced and unspliced E6/E7 mRNA species are transcribed from the viral genome of the high risk human papillomavirus 16, 18, and 31 (HPVs 16, 18 and 31) in uterine cervical carcinomas, but no spliced E6/E7 transcripts have been found in the low risk HPVs 6b and 11 in genital benign lesions. In this study, to examine the in vitro biological activities of the spliced and unspliced E6/E7 mRNAs of HPV16, we synthesized three HPV16 E6/E7 cDNAs, that is, cF (wt), c* I and c* II, for full-length E6/E7 mRNA, and two spliced mRNAs of E6*I/E7 and E6*/II/E7, respectively, from the cervical carcinoma cell line SiHa by reverse transcriptase PCR technique. We also constructed two cDNA mutants, cF (Do) and cF (Ac), which carry single point mutations at the splice donor site and the splice acceptor site, respectively. These E6/E7 cDNAs were cloned and tested for the ability to transform primary rat fibroblasts collaboratively with activated ras gene and to induce cellular DNA synthesis. c* I showed almost the same level of these activities as the subgenomic E7 fragment and cF (wt). The transforming activities of the splice site mutants, cF (Do) and cF (Ac), and of c*II were low compared to cF (wt) and none of these cDNAs showed any detectable abilities to induce cellular DNA synthesis. These results suggest that transcription of the E6* I/E7 mRNA is important for in vitro biological activities of the HPV16 E6/E7 region, possibly by high-level E7 protein production.

Animals↗
PubMed1992

Scoparic acid A, a beta-glucuronidase inhibitor from Scoparia dulcis.

The 70% EtOH extract of Scoparia dulcis showed inhibitory activity against beta-glucuronidase from bovine liver. Bioassay-directed fractionation of the active extract led to the isolation of three labdane-type diterpene acids, scoparic acid A [1] [6-benzoyl-12-hydroxy-labda-8(17), 13-dien-18-oic acid], scoparic acid B [2] [6-benzoyl-14,15-dinor-13-oxo-8(17)-labden-18-oic acid], and scoparic acid C [3] [6-benzoyl-15-nor-14-oxo-8(17)-labden-18-oic acid], the structures of which were established by spectral means, including X-ray analysis. Scoparic acid A was found to be a potent beta-glucuronidase inhibitor.

Acetylation↗
PubMed1991

Cell behaviour on polymer surfaces grafted with non-ionic and ionic monomers.

Following exposure to corona discharge, a polyethylene film was graft polymerized with different water-soluble monomers such as acrylamide (non-ionic), acrylic acid (anionic), 2-acrylamide-2-methyl propane sulphonic acid (anionic), styrene sulphonic acid sodium salt (anionic) and N,N-dimethylaminopropyl acrylamide (cationic). Attachment and proliferation of HeLa S3 cells were studied for grafted surfaces with different zeta potentials and contact angles. The polyethylene surface graft polymerized with styrene sulphonic acid sodium salt exhibited high cell attachment and protein adsorption, whereas the cells did not adhere to the 2-acrylamide-2-methyl propane sulphonic acid graft-polymerized surface, although both surfaces had high negative zeta potentials. Graft polymerization of acrylamide reduced the zeta potential of surface close to zero and rejected the cell attachment. The polyethylene surface became highly cell-adhesive through graft polymerization of the cationic N,N-dimethylaminopropyl acrylamide monomer, but too much grafting killed the attaching cells. Once the cells attached to a surface without being killed, they could proliferate at the same growth rate, whatever their surface zeta potential.

Acrylic Resins↗
PubMed1991

Coronary artery aneurysm without stenosis in association with Osler-Weber-Rendu disease--a case report.

A fifty-three-year-old woman presented with coronary artery aneurysm in association with Osler-Weber-Rendu disease (hereditary hemorrhagic telangiectasia) manifested also by large pulmonary arteriovenous fistulas. The arterial dye dilution curves were unusually distorted owing to the right-to-left shunts. The coronary artery aneurysm was located in multiple sites but was not accompanied by stenotic lesions. Coronary artery aneurysm without stenosis is a rare pathologic state and has not been previously reported in association with hereditary telangiectasia.

Arteriovenous Fistula↗
PubMed1990

Clinical evaluation of a new bilayer "artificial skin" composed of collagen sponge and silicone layer.

A bilayer "artificial skin" composed of an outer layer of silicone and an inner sponge layer of collagen and chondroitin sulphate has been developed by modifying the technique proposed by Yannas et al. (1980). Following experimental successes, the "artificial skin" was applied clinically. It was placed on the skin defects of 10 patients. Three weeks after application the outer layer of silicone sheet was peeled off and thin split thickness skin was grafted onto the newly synthesised dermis-like tissue. Secondary skin grafts took perfectly in all cases and postoperative appearance was satisfactory.

Adolescent↗
PubMed1990

Experimental study of a newly developed bilayer artificial skin.

A bilayer artificial skin composed of an outer layer of silicone polymer and an inner sponge layer of collagen containing chondroitin 6-sulphate was developed by modifying the technique proposed by Yannas et al. The artificial skin was placed on the skin defects on the backs of rats. Histological observation indicated that fibroblasts and capillaries infiltrated into the pores and filled in lattice spaces, resulting in synthesis of the connective tissue matrix and absorption of the original network of collagen and chondroitin 6-sulphate. Epidermal cells migrated from the edge of the wound between the two layers. Post-operative contracture in the wound with the artificial skin was significantly less than in the control.

Animals↗