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Biomedical subjects

Y Yamano

Publications and source records attributed to Y Yamano.

At least 91 records · Page 5Linked to original sources
PubMed1997

Molecular cloning of a canine metallothionein cDNA.

A canine metallothionein cDNA obtained from the liver of a cadmium-treated beagle was cloned and sequenced. Asn at position 4 conserved among all mammalian metallothionein-1 and metallothionein-2 is replaced by Asp in the canine metallothionein cDNA clone. Because the acidic amino acid doesn't exist at either position 10 or 11 in the deduced amino acid sequence, it is supposed that this cDNA is derived from canine metallothionein-1 mRNA. Northern blot analysis using the cDNA as a probe revealed the induction of the canine metallothionein mRNA expression in the liver and kidney of a cadmium-treated beagle. Thus, the canine metallothionein cDNA obtained in the present study should provide an useful tool for the molecular investigation of metallothionein in dog.

Amino Acid Sequence↗
PubMed1997

Cryofibrinogenemia with polyarthralgia, Raynaud's phenomenon and acral ulcer in a patient with Graves' disease treated with methimazole.

Cryofibrinogenemia is a cryopathy in which hypersensitivity to cold is a prominent feature. Cryofibrinogenemia developed in an 18-year-old Japanese female patient during methimazole therapy for Graves' disease. She developed cryopathy (livedo reticularis, Raynaud's phenomenon and acral ulcer) and polyarthralgia during methimazole therapy, and we detected cryofibrinogen in her plasma. Her symptoms resolved after administration of prostaglandins and anticoagulants. Several reports indicate that methimazole therapy induces autoantibody-related disease. In the present case, we cannot exclude the possibility that methimazole therapy contributed to the cryofibrinogenemia.

Adolescent↗
PubMed1997

Elevated serum levels of pantropic p53 proteins in chromium workers.

OBJECTIVES: This study investigated the possibility of applying serum pantropic p53 proteins in molecular epidemiologic studies, as a biomarker of environmental carcinogenesis. The serum levels of pantropic p53 proteins were determined in workers with past exposure to hexavalent chromium compounds. METHODS: Thirty-one male workers occupationally exposed to hexavalent chromium compounds in the production of chromium compounds for 0 to 23 years served as the exposed group. The referents were 10 volunteers without work-related exposure to chemicals. In the determination of pantropic p53 proteins, commercially available kits for enzyme-linked immunosorbent assay were used which quantitatively detected both mutant and wild-type human p53 proteins. RESULTS: The serum level of pantropic p53 proteins was in the range of 116.4 to 1122.6 pg/ml for the exposed workers and of 117.4 to 305.8 pg/ml for the referents. Nineteen percent of the exposed workers had a high p53 protein level (6 out of 31) when compared with the referents. All but 1 of the 6 workers had been occupationally exposed to chromium compounds for more than 11 years. Two of the 3 workers with a past history of lung cancer also showed high levels. CONCLUSIONS: Our findings confirm that the application of p53 proteins as a biomarker of environmental carcinogenesis merits further exploration.

Adult↗
PubMed1997

Functional evaluation of flail hip joint after periacetabular resection of the pelvis.

Five patients subjected to flail hip joint after resection of primary bone tumor of the pelvis involving acetabular region were examined with respect to function. When a thick portion of the supraacetabular pelvic neck was left in place, the operated legs functioned well regardless of whether the head of the femur was placed anterior or posterior to the iliac wing. In a patient who had only a thin portion of the iliac wing left in place and in those who underwent total excision of the ilium or hemiresection of the pelvis, the function of operated legs was poorer than with a thick portion of the supraacetabular pelvic neck left in place, but still more than 50% of leg function remained. Although flail hip joint results in a larger leg-length discrepancy than do other techniques, it enables favorable healing of the operative wound. Therefore, this method should be considered for women or sedentary patients with primary bone tumor of the pelvis involving acetabular region.

Acetabulum↗
PubMed1997

Clinical studies of second revision in total hip replacement.

Eleven patients (12 hips) underwent the second revision of total hip replacement. The mean age at the second revision was 61 years (range: 31 to 79); 2 patients were men and 9 women. Loosening of components was the most common reason for the revision surgery. Supplemental ring or wire-mesh reinforcement was used for the revision of the acetabular that had poor bone stock. On the acetabular side, an allograft was used in 4 hips; on the femoral side, a long stem was used in 11 hips. The mean operative time was 298 minutes (range: 195 to 525), and the mean bleeding volume was 2278 ml (range: 810 to 4800) which was about twofold more than that of the primary operation. The mean length of follow up after the second revision was approximately 5 years. In the clinical results, the mean total Japan Orthopaedic Association score was 56 points before the second revision and it was 70 points during the follow-up period. Pain score was especially improved after the second revision. On final roentgenographic examination there was noted a clear zone in three acetabular components and five femoral components. As yet, we have not experienced any case requiring a third revision.

Adult↗
PubMed1996

A kinetic comparative study on lymphocyte responses to superantigen and phytohemagglutinin: reciprocal presentation of superantigen on the surface of activated lymphocytes.

The kinetics of thymidine incorporation into fractionated T lymphocytes responding to bacterial superantigens were compared to those of cells activated by phytohemagglutinin (PHA). Evident differences between the kinetics of cell proliferation induced by PHA-P and staphylococcal enterotoxin B (SEB) emerged after Day 4 of culture. PHA-P-induced proliferative responses of peripheral blood mononuclear cells (PBMCs) and fractionated cells were apparent on Day 4 because of the presence of accessory cells in the initial cell suspensions. This gradually diminished in correlation with the decline of accessory cells in the cultures. The SEB-induced cell growth (PBMCs and CD4+ cells), however, continued until Day 9 of the culture. This finding suggests the reciprocal usage of MHC class II molecules to present SEB by activated T lymphocytes for superantigen-induced T cell activation and suggests that superantigen-related immune activation may depend in part on the potential of activated T lymphocytes to mediate reciprocal cell-to-cell interactions in the presence of superantigens. The decline observed in the CD8+ cell response to SEB and toxic shock syndrome toxin-1 after Day 4 was revived by exogenous recombinant interleukin-2 (rIL-2) supplementation, suggesting that the consequent autocrine or paracrine secretion of IL-2 from the responding cells is essential for subsequent cell proliferation. SEB-induced cell proliferation was significantly suppressed by anti-CD11a (lymphocyte function-associated antigen-1; LFA-1, alpha-chain) monoclonal antibody, and the inhibitory effect was most obvious in 6-day cultured CD8+ lymphocytes. The results suggest that the lymphocyte response associated with the cell-to-cell copresentation of superantigens involves LFA-1 molecules as an accessory factor, particularly in CD8+ lymphocytes.

Antibodies, Monoclonal↗
PubMed1996

Evaluation of the subacute pulmonary and testicular inhalation toxicity of diborane in rats.

This study aimed to clarify the subacute pulmonary and testicular inhalation toxicity of diborane (B2H6, CAS: 19287-45-7) in rats. Male Wistar rats were exposed for 8 weeks to 0.11 or 0.96 ppm of diborane for 6 hr/day, 5 days/week. The control group was exposed to filtered air. Bronchoalveolar lavage fluid (BALF), hematological, biochemical, and histopathological examinations were conducted. Sperm counts and spermatic morphological changes were examined in epididymides, and histopathological examination was carries out in testes. BALF examinations revealed that the percentage of neutrophils increased in a dose-dependent manner and that of macrophages decreased in rats exposed to 0.96 ppm. Quantities of total and individual phospholipids in BALF increased in rats exposed to 0.96 ppm. The proportion of phosphatidylglycerol plus sphingomyelin decreased, and phosphatidylethanolamine and phosphatidylinositol increased in rats exposed to 0.96 ppm. LDH increased in rats exposed to 0.96 ppm, and ALP showed a dose-dependent increase. In serum, alpha 1-antitrypsin and superoxide dismutase activities increased in rats exposed to 0.11 or 0.96 ppm. These changes showed dose-dependent effects on the lung in rats exposed to diborane, possibly indicating that the hyperenergia of type II cells with proliferation and/or hypertrophy without histopathological changes occurred even in rats exposed to 0.11 ppm. Testicular examinations revealed no particular findings. The TLV-TWA of diborane (0.1 ppm) seems to be high and possibly unsafe, considering that the no-observed-effect level over 8 weeks for rat lung was under 0.11 ppm.

Administration, Inhalation↗
PubMed1996

Role of platelet-activating factor and prostanoids in hemodynamic changes in rat experimental endotoxic shock.

The present experiments were conducted to elucidate the role of platelet-activating factor (PAF) and cyclooxygenase products in the cardiovascular responses to endotoxin in anesthetized rats. Endotoxin (10 mg/kg, i.v.) induced hypotension that was accompanied by a decrease in cardiac output and an increase in calculated total peripheral resistance, suggesting that this hypotension mainly resulted from the reduced cardiac output. The endotoxin-induced decrease in cardiac output and hemoconcentration was significantly attenuated by TCV-309 (a PAF receptor antagonist), ibuprofen (a cyclooxygenase inhibitor) or S-1452 (a thromboxane A2/prostaglandin H2-receptor antagonist). During the 3-hr observation period following endotoxin administration, ibuprofen and S-1452 showed only early protection and TCV-309 showed late attenuation of the endotoxin-induced hypotension. Tachycardiac responses to endotoxin were only blocked by ibuprofen but not by TCV-309 or S-1452. These results suggest that both PAF and cyclooxygenase product(s), including thromboxane A2, mediate the decrease in cardiac output and hypotension in rat experimental endotoxic shock. Cyclooxygenase product(s) other than thromboxane A2 or prostaglandin endoperoxide may be involved in the endotoxin-induced increase in heart rate.

Animals↗
PubMed1996

Immunohistochemical localization of metallothionein in the olfactory pathway of dogs.

Dogs raised in the open air were used in this study. Metallothionein (MT) immunoreactivity was observed in the nucleus and/or cytoplasm of sustentacular cells of the olfactory epithelium in the nasal mucosa, whereas there was few MT-positive cells in the respiratory epithelium. MT immunoreactivity was also observed in astrocytes in all layers of the the olfactory bulb cortex; glial cells surrounding the glomeruli in the olfactory bulb showed prominent immunoreactivity for MT. Adult dogs exhibited stronger immunoreactivity for MT than young. Northern blot analysis demonstrated substantial levels of MT mRNA in the olfactory mucosa and olfactory bulb. Physiological roles of MT localized in the olfactory pathway of dogs were discussed.

Age Factors↗
PubMed1996

The role of physicochemical properties of biomaterials and bacterial cell adhesion in vitro.

This study was undertaken to investigate the physicochemical aspects of the interaction between the surface of biomaterials and bacterial cell membranes in vitro, aimed at studying the mechanisms of bacterial adhesion to biomaterials. Correlations were made between the number of adherent bacterial cells (S. aureus) and each of the calculated components of surface free energy (i.e., dispersion, polarity and hydrogen bond) of biomaterials. The effect of antibodies to cell-adhesion molecules on bacterial adhesion was also studied using monoclonal antibodies to vitronectin receptor, fibronectin receptor and CD44. This study indicates the polarity component of surface free energy plays a dominant role in the process of bacterial adhesion at least in vitro. The number of cells adherent to materials decreased to 44-73% of the control value in the presence of antibodies tested, showing that cell adhesion molecules affect adherence to biomaterials. Moreover, the results suggested that bacterial adhesion was prevented by specific blockade of cell adhesion molecule receptors.

Antibodies, Monoclonal↗
PubMed1996

[A clinical evaluation of fluconazole in deep seated fungal infections associated with hematological disorders].

The effectiveness of fluconazole on deep seated fungal infections associated with hematological disorders was evaluated in a multicenter clinical study. The underlying diseases included acute myeloblastic leukemia, acute lymphocytic leukemia, malignant lymphoma, adult T cell leukemia, multiple myeloma and others. Fluconazole (FLCZ) was administrated 100-400 mg/day intravenously or orally to 79 patients with systemic fungal infections complicated with hematological disorders and it was possible to evaluate clinical efficacies in 60 patients. 27 patients were diagnosed as having determinate systemic fungal infections and 33 patients suspected fungal infections. The clinical efficacies were 81.5% (22/27) in patients with diagnosed fungal infections and 57.6% (19/33) in patients with suspected fungal infections. The overall clinical efficacy was 68.3% (41/60). No side effects such as gastrointestinal symptoms, vascular pain and renal dysfunction were observed in this study. As for abnormal laboratory test, transient increases in GOT, GPT, Al-P, LDH, serum Na, Cl and decrease in serum K were observed in 9 patients (11.4%). These results indicated that FLCZ has a high therapeutic efficacy on deep seated fungal infections in patients with hematological disorders.

Aged↗
PubMed1996

The distribution of differentiated phenotypes of chondrocytes in osteoarthritic knee.

Articular cartilage consists of chondrocytes and a cartilagenous matrix produced by these cells. The cartilaginous matrix is considered to undergo various changes in response to the surrounding environment. In this study, cartilaginous changes related to osteoarthritis of the knee were investigated. Histological changes were apparent in medical joint lesions, and changes typical of osteoarthritis, such as cell clustering and disruption of the matrix, were always observed. Degeneration was less severe in the lateral joint lesions. A biochemical analysis was undertaken and the molecular size of the proteoglycan produced in the matrix was measured by glycerol density gradient ultracentrifugation method, following pulse labeling with 35S-Sulfuric acid. The proteoglycan produced in the histologically altered regions tended to be of low molecular size. However, the size was still significantly larger than that of proteoglycans located in the nonarticular tissues such as synovia membrane, so the differentiated phenotype of chondrocytes persisted.

Cartilage, Articular↗
PubMed1995

Production of chronic compression of the cauda equina in rats for use in studies of lumbar spinal canal stenosis.

STUDY DESIGN: The pathophysiology of lumbar spinal canal stenosis was analyzed with a new model in rats. OBJECTIVES: To produce chronic compression of the cauda equina in rats for analysis of the pathophysiology of lumbar spinal canal stenosis. SUMMARY OF BACKGROUND DATA: Models of compression to date have involved acute or subacute compression. A model of chronic compression has not been available. METHODS: A stainless steel wire fastened around the spine at L5 in 3-week-old rats, with a plate inserted against the ventral aspect of the vertebra to protect it from the wire. as the rats grew, the wire cut into the spinal canal. One year after the operation, canal stenosis was present without paralysis of the back limbs. RESULTS: Stenosis seen in sagittal sections, as a percentage of the original width, was 51.6 +/- 6.2% (mean +/- standard deviation). In histologic analysis of the region near the wire, findings included axonal degeneration, demyelination, vacuolar degeneration of the nerve fibers, and narrowing the intradural blood vessels with a decrease in their number. Cephalad and caudad to the wire, congested intradural blood vessels, degenerative foci near these congested vessels, fibrosis around these foci, congested epidural vessels, and fibrosis around these vessels were observed. During electrophysiologic analysis (six rats with stenosis), the conduction velocity of the cauda equina was found to be delayed. CONCLUSIONS: The histologic and electrophysiologic findings in this animal model were similar to findings in human subjects, so rats prepared in this way should be useful for study of chronic compression of the cauda equina.

Animals↗
PubMed1995

Role of porins in the antibiotic susceptibility of Pseudomonas aeruginosa: construction of mutants with deletions in the multiple porin genes.

We inserted deletions in the chromosomal genes of Pseudomonas aeruginosa coded for the outer membrane porins, proteins C, D2, or E1, and all possible combinations of these proteins by the gene replacement technique and selecting for imipenem-resistance. Determination of the minimum inhibitory concentrations of beta-lactams, fluoroquinolones, chloramphenicol and gentamicin in these mutants revealed that most mutants showed equal susceptibility to the porin-sufficient strain. The only exception was that imipenem and meropenem showed increased minimum inhibitory concentrations in all of the mutants lacking protein D2. These results firmly established that the P. aeruginosa porins identified so far form the pores do not accommodate the passage of most antipseudomonal antibiotics, with the exception of carbapenems.

Bacterial Outer Membrane Proteins↗
PubMed1995

Mutagenesis and the molecular modeling of the rat angiotensin II receptor (AT1).

The molecular interaction involved in the ligand binding of the rat angiotensin II receptor (AT1A) was studied by site-directed mutagenesis and receptor model building. The three-dimensional structure of AT1A was constructed on the basis of a multiple amino acid sequence alignment of seven transmembrane domain receptors and angiotensin II receptors and after the beta 2 adrenergic receptor model built on the template of the bacteriorhodopsin structure. These data indicated that there are conserved residues that are actively involved in the receptor-ligand interaction. Eleven conserved residues in AT1, His166, Arg167, Glu173, His183, Glu185, Lys199, Trp253, His256, Phe259, Thr260, and Asp263, were targeted individually for site-directed mutation to Ala. Using COS-7 cells transiently expressing these mutated receptors, we found that the binding of angiotensin II was not affected in three of the mutations in the second extracellular loop, whereas the ligand binding affinity was greatly reduced in mutants Lys199-->Ala, Trp253-->Ala, Phe259-->Ala, Asp263-->Ala, and Arg167-->Ala. These amino acid residues appeared to provide binding sites for Ang II. The molecular modeling provided useful structural information for the peptide hormone receptor AT1A. Binding of EXP985, a nonpeptide angiotensin II antagonist, was found to be involved with Arg167 but not Lys199.

Amino Acid Sequence↗