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Biomedical subjects

T Hayashida

Publications and source records attributed to T Hayashida.

At least 73 records · Page 4Linked to original sources
PubMed1985

Distribution of gentamicin by immunofluorescence in the guinea pig inner ear.

We studied the distribution of gentamicin in the inner ear, brain and kidney of the guinea pig following intraperitoneal administration or perfusion of gentamicin through the perilymphatic space. The resulting histopathological changes were examined by immunofluorescence using antigentamicin antiserum. After perfusion of gentamicin through the perilymphatic space, specific fluorescence was found in the cochlea, and was especially prominent in the outer hair cells, basilar membrane and basilar crest. Although no fluorescence was observed in the cochlea following intraperitoneal administration of high doses of gentamicin, type I hair cells in the vestibule were seen to be selectively stained with the antibody. Furthermore, some of the vestibular ganglion cells, Purkinje cells and unidentified nuclei in the brain stem were also stained. In particular, fine granules showing relatively intense fluorescence were recognized in the cytoplasm of the stained cells. In the cortex of kidney, only proximal tubular cells were stained with intense fluorescence. Our results suggest that the aminoglycoside antibiotics have two sites of action: one is the cell membrane of the sensory hair cells and the other is the cytoplasm.

Animals↗
PubMed1985

Malignant fibrous histiocytoma of maxilla following radiotherapy for bilateral retinoblastoma.

A 20-year-old man developed a malignant fibrous histiocytoma in the right maxilla 19 years after irradiation for bilateral retinoblastoma. The incidence of second tumours in patients who survived bilateral retinoblastoma treated with radiation was 8.5 per cent. Malignant fibrous histiocytomas which arise in a site of prior radiation are fatal. The present case is presumed to have the autosomal dominant retinoblastoma gene, not associated with deletion of the q 14 band of chromosome 13. The patient succumbed to the second tumour.

Adult↗
PubMed1984

Biochemical study of cholesteatoma and cholesterol granuloma--occurrence of delta 7-cholestenol in the tissues of cholesteatoma.

Qualitative and quantitative analyses of sterol derivatives in the tissue of cholesteatoma and cholesterol granuloma were performed by gas-liquid chromatography, mass spectrometry and mass fragmentography after the extraction of total lipids with organic solvents. Cholesterol was the major component in both tissues. The molar ratios of cholesterol to lipid-bound phosphorus in cholesterol granulomas were higher than those in cholesteatomas. In addition, delta 7-cholestenol (lathosterol) was contained in all tissues of cholesteatoma examined. However, cholesterol granuloma tested did not contain delta 7-cholestenol, indicating that the metabolism of cholesterol differed from that in cholesterol granuloma.

Chemical Phenomena↗
PubMed1983

[A clinical study on surgical patients with disseminated intravascular coagulation: with special reference to the occurrence of major organ failures].

Among 113 consecutive patients with disseminated intravascular coagulation (DIC), twenty cases who developed this condition under surgical intervention are the subject of this study. At the onset of DIC, fourteen cases were suffered from severe infection. Coagulation study in these patients revealed decreased platelet counts and prolonged prothrombin time. There was marked increase in fibrinogen degradation products and positive ethanol gelation test was frequently observed. These findings were analogous to those found in the more chronic presentations of DIC in the patients with neoplastic diseases, however, plasma concentration of fibrinogen was normal. Antithrombin III level was extremely low in the patients with surgical DIC. The patients with DIC in surgery took acute or subacute courses with very high incidence of major organ failure. The patients with dysfunction of more than three organs were seen in eight of 20 cases. The lungs, kidneys, liver and gastrointestinal tracts were involved in the descending order of frequency. Fourteen patients died and six of these were autopsied. All had multiple fibrin thrombi in more than two organs. The numbers and sites of microthrombi in the major organs were well matched with the clinical manifestations. These results suggested that DIC might be one of the precipitating factors of multiple organ failure.

Acidosis↗
PubMed1982

Hamster growth hormone. Species specificity and physiological changes in blood and pituitary concentrations as measured by a homologous radioimmunoassay.

A specific and sensitive homologous radioimmunoassay (RIA) for determination of golden hamster growth hormone (GH) is described and compared to a heterologous hamster GH RIA. Using the homologous system, cross-reactivity experiments between golden hamster GH on one hand, and pituitary extracts from two other hamster species, and purified GHs from several rodent and mammalian species, suggested that hamster GH differs from other rodent and mammalian GHs to a greater extent than rat GH. Using the homologous method, we have determined that, in the golden hamster, diurnal plasma fluctuations have a mean interpeak interval of 70-80 min, that serum GH concentrations are affected by nyctohemeral differences in lighting, by ether vapors, by animal's gender, and by starvation and refeeding. Basal GH concentrations were not influenced by exposure to different photoperiods or by removal of the gonads. A heterologous hamster GH RIA, which utilizes a radioiodinated rat GH and monkey antihamster GH serum, represents the most advantageous method for the measurement of hamster GH because of its high sensitivity (0.3 ng/ml), low limit of detection (46 pg/ml), high antiserum binding to iodinated rat GH, and the ability to measure rat and mouse GHs in addition to hamster GH. Immunological differences between hamster, rodent, and other mammalian GHs are diminished when heterologous, rather than homologous, tracer is used.

Animals↗
PubMed1981

Characteristics of growth hormone isolated from sturgeon (Acipenser güldenstädti) pituitaries.

GH was isolated and characterized from pituitaries of a primitive bony fish, sturgeon (Acipenser güldenstädti). Sturgeon GH was very active in a mammalian GH assay, the rat tibia test. Relative to ovine GH (NIH-GH-S9), sturgeon GH gave a parallel dose-response slope and had a potency of 0.4. Sturgeon GH also showed strong cross-reaction in a snapping turtle GH RIA, comparable to that shown by tetrapod GHs and much greater than that of modern bony fish (teleost) GH. These results, predicted by earlier experiments using pituitary extracts of related species, support the hypothesis that GHs from primitive fish are more closely related to tetrapod GHs than are teleost GHs. Chemical characterization of sturgeon GH, including amino acid terminal residue analyses, amino acid composition, molecular weight determination, and electrophoresis on polyacrylamide gels, indicated that this GH is similar to GHs previously isolated from a teleost and representative species of every tetrapod class. These data provide strong additional evidence that the molecular structure of GH has been highly conserved during evolution. (Endocrinology 108: 377, 1981)

Amino Acids↗
PubMed1977

Human somatotropin: restoration of full biological activity by noncovalent interaction of a natural and a synthetic fragment of the hormone.

The recombinant hormone obtained by noncovalent interaction of the natural NH2-terminal fragment (consisting of 134 amino acid residues) with a synthetic COOH-terminal fragment of 52 amino acids of the reduced-carbamidomethylated human somatotropin molecule is found to exhibit full biological activity of the native hormone as evidenced by the tibia test. Radioimmunoassay data indicate that the semisynthetic recombinant hormone possesses essentially full immunoreactivity as compared to the native one. In addition, circular dichroism and fluorescence emission spectra of the semisynthetic recombinant are identical to that of the undisociated, plasmin modified, reduced-carbamidomethylated hormone.

Biological Assay↗