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Biomedical subjects

K Ohya

Publications and source records attributed to K Ohya.

At least 145 records · Page 8Linked to original sources
PubMed1986

Detection of adult T-cell leukemia virus (ATLV) bearing lymphocytes in concentrated red blood cells derived from ATL associated antibody (ATLA-Ab) positive donors.

Adult T cell leukemia associated antibody (ATLA-Ab) positive persons were screened by indirect immunofluorescence (IF) testing. Their lymphocytes were collected from concentrated red blood cells (CRC), and cultured in vitro with and without phytohemagglutinin (PHA) for 10 days. The expression of ATL virus (ATLV) positive lymphocytes during the in vitro culture was then analyzed by IF assay using mouse monoclonal antibody ATL-19 reactive to p19 core protein of ATLV. 97% of ATLA-Ab positive CRC (36 cases) demonstrated ATLV positive lymphocytes after being cultured for more than 10 days with PHA, whereas, none of ATLA-Ab negative CRC (22 cases) demonstrated ATLV positive lymphocytes. All of the 10 ATLA-Ab positive CRC that were stored for 2, 4, and 7 days contained lymphocytes which expressed ATLV after in vitro culture, while 7 of 10 CRC stored for 14 days and only 1 of 10 CRCs stored for 20 days, expressed ATLV positive lymphocytes. This data indicates that almost all of the ATLA-Ab positive blood contained ATLV positive lymphocytes, and that the in vitro appearance of these ATLV positive lymphocytes was reduced by storing the CRC for more than 14 days.

Adolescent↗
PubMed1986

Immunological studies on adult T cell leukaemia virus (ATLV) carriers.

Adult T cell leukaemia associated antibody (ATLA-Ab) positive people who were considered to be adult T cell leukaemia virus (ATLV) carriers were found in 0.75% of the adult population in the non-endemic area of Nagoya, Japan. Immunological studies on these people revealed that T lymphocyte subpopulations, as defined by nine monoclonal antibodies reactive to T lymphocyte surface antigens including T cell activation antigen, showed no differences between ATLA-Ab positive and ATLA-Ab negative individuals. Only a slightly higher percentage of Ia positive T lymphocytes was found in ATLA-Ab positive persons. Furthermore, the serum IgG level and the antibody titre of cytomegalovirus were significantly increased in ATLA-Ab positive individuals, while serum IgA, IgM level and the antibody titre of herpes simplex virus and mumps virus, showed no differences in both groups. This data suggests the possibility that ATLV carriers have some mild immunological abnormalities.

Adolescent↗
PubMed1985

Effect of bisphosphonates on prostaglandin synthesis by rat bone cells and mouse calvaria in culture.

Bisphosphonates are potent inhibitors of bone resorption and also inhibit prostaglandin (PG) E2 synthesis in bone cells. Therefore we have investigated whether a correlation exists between inhibition of bone resorption and inhibition of PGE2 formation. Initially, bisphosphonates were tested for their effect on the release of [14C]PGE2 from rat calvaria cells labelled with [14C]arachidonic acid and stimulated by bradykinin, thrombin and mechanical manipulation. The effect on [14C]-PGE2 synthesis was not correlated with the known inhibitory activity of bisphosphonates on bone resorption. Mouse calvaria were then treated with epidermal growth factor (EGF) to induce PGE2 synthesis and bone resorption, with or without bisphosphonates. The bisphosphonates either decreased, had no effect or increased PGE2 production, but all inhibited the release of calcium. Finally, the bisphosphonates were given in vivo to mice before explantation of the calvaria. Some of the bisphosphonates decreased the production of PGE2, suggesting that these compounds may have such an effect in vivo. But again no relationship between the effect on PGE2 synthesis and bone resorption was found. Thus, these experiments show the inhibitory effect of bisphosphonates on bone resorption is unlikely to be explained only by their effect on PGE2 synthesis.

Animals↗
PubMed1983

Determination of 20 alpha-hydroxy-9 beta,10 alpha-pregna-4,6-dien-3-one in plasma by selected ion monitoring.

A selected ion monitoring (SIM) method has been devised for the determination of metabolites of dydrogesterone, 20 alpha-hydroxy-9 beta,10 alpha-pregna-4,6-dien-3-one (DHD) and DHD glucuronide, in plasma. Using testosterone as an internal standard (IS), DHD and IS were extracted with n-hexane and were purified by means of magnesium oxide column chromatography. The purified DHD and IS were converted to their diheptafluorobutyryl derivatives (DHD diHFB and testosterone diHFB) with heptafluorobutyric anhydride in acetone for analysis by SIM. SIM was carried out with a 2% OV-17 column (1 m) at 230 degrees C by monitoring the molecular ions of the derivatives (m/z 706 for DHD diHFB, m/z 680 for testosterone diHFB). DHD was determined from a calibration curve using a peak area method. The determination limit of the devised method was about 5 ng DHD per ml of plasma and the reproducibility was within +/- 6% of the coefficient of variation for 30 ng of DHD per ml of plasma or above.

Dydrogesterone↗
PubMed1980

Determination of ethambutol in plasma using selected ion monitoring.

The determination of ethambutol in plasma is described. Using ethambutol-d4 as an internal standard, ethambutol and the internal standard were extracted with chloroform under alkaline conditions, and converted into their trifluoroacetyl derivatives with trifluoroacetic anhydride in benzene-pyridine (4:1). Selected ion monitoring was carried out by monitoring the peaks at m/z 294 and 296 corresponding to the fragment ion [M/2]+ of the derivatives. Ethambutol was determined by use of the peak height ratio of the peak at m/z 294 against that at m/z 296. The method was utilized for studying the bioavailability and pharmacokinetics of the drug.

Animals↗
PubMed1980

Sensitive and selective method for the determination of chlormezanone in plasma by electron-capture gas chromatography.

A sensitive and selective determination method of chlormezanone in plasma has been divised. Chlormezanone in plasma was extracted with toluene at pH 4.5, and converted into p-chlorobenzaldehyde in 0.1 N NaOH. Using p-bromobenzaldehyde as an internal standard, the hydrolysis product and the internal standard were extracted with n-hexane, and the extract was concentrated in vacuo in the presence of isoamyl alcohol to prepare the sample solution. The sample solution was submitted to electron-capture gas chromatography. Chlormezanone was determined by use of the peak height ratio of p-chlorobenzaldehyde against the internal standard. The method was utilized successfully for pharmacokinetic studies of chlormezanone in plasma.

Benzaldehydes↗
PubMed1980

Analysis of drugs by pyrolysis. II--An improved method for the determination of carpronium chloride in plasma by selected ion monitoring.

A sensitive and specific method has been devised for the determination of carpronium chloride, a parasympathomimetic agent, in plasma. The method is based on selected ion monitoring combined with the pyrolysis reaction of (3-isopropoxycarbopropyl)trimethylammonium chloride derived by transesterification of the drug. Carpronium chloride-[2H9] is used as an internal standard. The drug and the internal standard are separated from deproteinized plasma by ion pair extraction, and converted into isopropyl ester derivatives. The derivatives are pyrolysed to produce the respective isopropyl N,N-dimethyl-gamma-aminobutyrates available for selected ion monitoring. Measurement is carried out in the electron impact mode by monitoring the fragment ion [M-OC3H7]+ (m/z 114, 120). The method is applicable to 5 ng ml-1 plasma with about 10% coefficient of variation, and has been utilized successfully for the pharmacokinetics of carpronium chloride in man.

Animals↗
PubMed1979

Identification of carpronium chloride and its metabolite in human urine by field desorption mass spectrometry using deuterium labelling.

The identification of carpronium chloride and a metabolite in human urine has been performed by means of field desorption mass spectrometry using deuterium labelling. Essential points in this study are the simultaneous administration of a deuterium labelled drug ([2H9]carpronium chloride), a purification procedure by ion pair extraction with an iodine reagent, and the use of paper electrophoresis to examine the degree of clean-up. The field desorption mass spectra of the purified extracts obtained from sample urine gave a characteristic pattern resulting from the carpronium cation (m/z 160, m/z 169) and a metabolite of the N-(3-carbohydroxypropyl)trimethyl ammonium cation (m/z 146, m/z 155).

Adult↗
PubMed1978

Effects of colchicine on osteoblast in rat: an ultrastructural study.

The present study was an attempt to investigate the effects of colchicine on the ultrastructure of rat osteoblasts with special reference to the microtubular function in vivo. Rats were killed at intervals of 2, 4, 8, 12 and 24 hours after the colchicine injection (0.1 mg per 100 g of body weight, subcutaneously). At 2 and 4 hours after the injection, the secretory granules and small vesicles accumulated in the Golgi area of the osteoblasts. The dilated spherical cisterna of the rough endoplasmic reticulum and the large vacuoles appeared, being located in the periphery of the cell. Microtubules were rarely found in the cytoplasm. Small masses of microfilaments of 80 to 110 A in diameter were found also in the cytoplasm. According to the special staining for collagen, it was indicated that the contents of the secretory granules might be collagen-like materials. At 8 hours after the injection, the shape of the osteoblasts transformed to a round profile and the autophagic vacuoles increased in the cytoplasm. At 12 and 24 hours after the injection, the osteoblasts seemed to be destroyed by the breakdown of the plasma membrane and by the increase of the autophagic vacuoles. It is suggested that colchicine affects the secretory process of the bone matrix and the cytoskeletal system of the osteoblasts by interfering with the structure and the function of the microtubules and colchicine also interferes with the function of the plasma membrane followed by the destruction of the osteoblasts.

Animals↗
PubMed1977

Analysis of drugs by pyrolysis. I. Selected ion monitoring combined with a pyrolysis method for the determination of carpronium chloride in biological samples.

In order to establish an analytical method for carpronium chloride, a parasympathomimetic agent, the pyrolysis reaction of carpronium chloride was examined in a g.c.m.s. system, which revealed that gamma-butyrolactone was produced directly from the drug as the main pyrolysis product. In the case of conversion of [2,2,3,3-2H4]carpronium chloride into the deuterated gamma-butyrolactone, 2H/1H scrambling was observed and confirmed to occur during the pyrolysis process of the deuterated compound. The proportion of gamma-[2H4]butyrolactone among the pyrolysis products was almost independent of the operating conditions, so [2,2,3,3-2H4]carpronium chloride was of practical use as an internal standard for selected ion monitoring. By incorporation of the pyrolysis reaction of carpronium chloride with selected ion monitoring and the use of [2,2,3,3-2H4]carpronium chloride as an internal standard, a rapid, sensitive and selective method was devised for the determination of the drug in biological samples. The method was utilized successfully for the biopharmaceutical studies of carpronium chloride in ma.

4-Butyrolactone↗
PubMedDate not supplied

Asymptomatic Becker muscular dystrophy: expression of dystrophin and dystrophin-related protein.

The expression of dystrophin and a dystrophin-related protein in muscle from 3 asymptomatic Becker muscular dystrophy patients is reported. Histology demonstrated moderate variation in fiber size with clustered basophilic regenerating fibers. Immunostaining for dystrophin revealed a patchy appearance on most fibers, but never on clustered regenerating fibers. Those regenerating fibers did, however, have positive immunoreactivity to a dystrophin-related protein. It is speculated that overexpression of the dystrophin-related protein in regenerating muscle fibers may contribute to the slow progression of muscle weakness or atrophy.

Biopsy↗