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Biomedical subjects

K Osanai

Publications and source records attributed to K Osanai.

At least 19 recordsLinked to original sources
PubMed1991

Chromosomal behavior in starfish (Asterina pectinifera) zygotes under the effect of aphidicolin, an inhibitor of DNA polymerase.

When calf thymus histones were labeled fluorescently and microinjected into oocytes of the starfish, Asterina pectinifera, the labeled histones visualized chromosomes during maturation division and cleavage. In doing so, we confirmed the previously reported phenomenon that chromosomes became incompetent at the first cleavage in the aphidicolin-treated egg, although cleavage itself took place. Moreover, we found that chromosomes were aligned at the equator of the metaphase spindle of the first cleavage and that they did not separate into two groups at all, but made a lump in the middle of the spindle. Chromosomes finally entered one blastomere, although they did not participate in the following karyokinesis. DNA and microtubules were examined by cytochemistry and immunofluorescence in order to investigate the relation between chromosome movement and the microtubular cytoskeleton. The mitotic apparatus developed and grew in the aphidicolin-treated cells in the same manner as those in normal cells without normal chromatin condensation or chromosome movement during the first cleavage. However, the mitotic apparatus consisted of two asters without the spindle formed at subsequent cleavages. Electron microscopic study revealed that chromosomes did not condense normally and kinetochores were not detected during the first cleavage. These results indicate that the dynamic changes in microtubular structures during mitosis have poor relation with the chromosome behavior such as prophase chromosome condensation and anaphase chromosome movement.

Anaphase↗
PubMed1991

Changes of lung surfactant and pressure-volume curve in bleomycin-induced pulmonary fibrosis.

We investigated whether alveolar surface force increased and participated in the lung pressure-volume relationship in bleomycin-induced pulmonary fibrosis in hamsters and, if so, whether lung surfactant was hampered in the lungs. On the air-filled pressure-volume curve, decreases of lung volume from control level were significantly higher at 3-8 cmH2O pressure on day 10 than on day 30. Because the change of lung tissue elasticity evaluated from the saline-filled pressure-volume curve was equal for the 2 days, the higher decrease of air volume on day 10 was due primarily to contribution of alveolar surface force. Pressure differences between deflation limbs of air-filled and saline-filled pressure-volume curves, which represented net alveolar surface force, were significantly higher at any lung volume between 50 and 90% total lung capacity on day 10, but almost no significance was observed on day 30. Phospholipid concentration in bronchoalveolar lavage fluid significantly decreased on day 10 but had improved by day 30. Analysis of phospholipid species in purified lung surfactant showed decreased fractions of disaturated phosphatidylcholine and phosphatidylglycerol on day 10. Surface-active properties of the surfactant, measured by a modified Wilhelmy balance, were remarkably hampered on day 10, but most of them had improved by day 30. We consider that the quantitative and functional abnormalities of lung surfactant have a part in the aggravation of lung mechanics in the acute phase of pulmonary fibrosis.

Animals↗
PubMed1991

Chemical conversion of corticosteroids to 3 alpha,5 alpha-tetrahydro derivatives. Synthesis of 5 alpha-cortol 3-glucuronides and 5 alpha-cortolone 3-glucuronides.

The synthesis of the 3-glucuronides of 5 alpha-cortol-20 alpha, 5 alpha-cortolone-20 alpha and their 20 beta-epimers is described. The 5 alpha-cortol 20,21-diacetates (12, 17) and 5 alpha-cortolone 20,21-diacetates (14, 19) were the key intermediates. Sodium borohydride reduction of the carbonyl group at C-20 in 5 alpha-tetrahydrocortisol 3-tert-butyldimethylsilyl ether 17,21-acetonide (8) gave the 20 alpha-hydroxy-acetonide (9). Selective removal of the acetonide ring was successful when the 20 alpha-acetoxy-17 alpha,21-acetonide (10) was treated with 50% acetic acid. Subsequent acetylation with acetic anhydride in pyridine, followed by removal of the protecting group at C-3 in the silyl ether-acetate (11) gave the desired 20 alpha-intermediate (12). The 11-ketone (14) was prepared from 11 by oxidation with pyridinium chlorochromate, followed by desilylation. The 20 beta-acetates (17, 19) were synthesized from 21-acetoxy-3 alpha,11 beta,17 alpha-trihydroxy-5 alpha-pregnan-20-one 3-tert-butyldimethylsilyl ether (15). Introduction of the glucuronyl residue at C-3 was carried out by means of the Koenigs-Knorr reaction.

Adrenal Cortex Hormones↗
PubMed1991

[Autologous blood transfusion aided with erythropoietin in transurethral resection of the prostate].

Erythropoietin (EPO) with an established clinical efficacy in renal anemia has in recent years become applied as an aid to autologous blood transfusion in surgical patients. This report describes our experience with autotransfusion along with the use of EPO in transurethral resection of the prostate (TUR-P), indicating its usefulness. Ten patients with benign prostatic hypertrophy aged 60 to 74 years received 3000 units of EPO, with an iron preparation, nine times beginning 3 weeks prior to operation. Autologous blood of 300 ml was collected from the patient each at 2 and 1 week before operation and was used at TUR-P. Five other patients who underwent TUR-P with the same volume of autotransfusion accompanied by preparative medication with the iron alone served as controls. In the EPO treated group (mean age, 68.3 years) the mean value for hemoglobin concentration (Hb) was 14.0 +/- 1.6 g/dl on the day of operation, which showed a recovery rate of 94.9 +/- 5.4% (Hb recovery rate) as against the pre-EPO treatment value (mean: 14.8 +/- 1.3 g/dl). This Hb recovery rate was significantly greater (p less than 0.001) when compared to 82.2 +/- 2.5% in the control group (mean age, 68.2 years). Of the EPO treated patients, those in their sixties (n = 6; mean age, 66.3 years) exhibited a significantly higher Hb recovery rate (98.3 +/- 3.5%) than the rate (89.9 +/- 3.0%) for patients in their seventies (N = 4; mean age, 71.3 years) (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion, Autologous↗
PubMed1991

[Clinical studies of bacteriuria in renal transplantation recipients. Correlation with pyuria and symptomatic genitourinary tract infection].

The clinical state of bacteriuria and its correlation with pyuria and symptomatic genitourinary tract infection (GUTI) were studied in 42 renal transplantation recipients who were followed up in the Kidney Center of Tokyo Women's Medical College over 6 months and who showed bacteriuria more than 3 times between January and December in 1987. The results were as follows. 1) Of the 42 recipients, bacteriuria was found less than 5 times in 19 patients, 6 to 10 times in 18 patients and more than 11 times in 5 patients. There was a tendency for the same bacteria to be isolated several times from the same patient. The most commonly isolated bacterias were Enterobacter, Enterococcus, Serratia and E. coli. 2) Bacteriuria was accompanied by pyuria in 33 patients (79%) and by symptomatic GUTI in 12 patients (29%). Bacteriuria without pyuria was shown in 9 patients (21%) without symptomatic GUTI and it was suggested that bacteriuria did not result in graft hypofunction after two years. 3) Of 16 patients with bacteriuria accompanied by pyuria, symptomatic GUTI occurred in 9 patients (56%). Of these, one patient was found to have VUR of the transplanted kidney, another was found to have VUR of the native kidney, and a third patient died due to interstitial pneumonitis presumably as a result of overimmunosuppression. Transplantation recipients with bacteriuria accompanied by pyuria develop symptomatic GUTIs frequently and should be treated with proper antibacterial agents. When bacteriuria continues, further examination should be performed for an organic disease of the urinary tract or an overimmunosuppressed state. When a patient shows bacteriuria without pyuria, chemotherapy is not needed and it is sufficient to observe the course carefully.

Adult↗
PubMed1990

Chemical conversion of corticosteroids to 3 alpha,5 alpha-tetrahydro derivatives. Synthesis of allotetrahydrocortisol glucuronides and allotetrahydrocortisone glucuronides.

The synthesis of the 3- and 21-glucuronides of allotetrahydrocortisol (allo-THF) and allotetrahydrocortisone (allo-THE) is described. 5 alpha-Dihydrocortisol (5) was prepared by selective hydrogenation of 21-acetoxy-3, 11 beta, 17 alpha-trihydroxy-3,5-pregnadien-20-one 3-ethyl ether (3), followed by acid hydrolysis and saponification. When 5 alpha-dihydrocortisol 21-tetrahydropyranyl ether (6) was treated with potassium tri-sec-butylborohydride in tetrahydrofuran under mild conditions, regioselective and stereoselective reduction at C-3 took place to give allo-THF 21-tetrahydropyranyl either (7). This compound was converted into the 3- and 21-monoacetates of allo-THF and allo-THE, key intermediates. Introduction of the glucuronyl residue at C-3 or C-21 was carried out by means of the Koenigs-Knorr reaction. Prior to saponification yielding the 3-glucuronides (20,23), the alkali-sensitive ketol side chain at C-17 was protected as 20-semicarbazones.

Adrenal Cortex Hormones↗
PubMed1990

[Effects of vitamin E deficiency on bleomycin-induced pulmonary fibrosis in hamsters].

We examined the effect of free radicals on lung defense mechanism in bleomycin (BLM)-induced pulmonary fibrosis in hamsters. The concentration of vitamin E (VE) in the lung tissue increased significantly after intratracheal BLM administration. VE deficient hamsters showed increased lipid peroxide values in the lung tissue at a very early stage after BLM treatment. This was followed by decreased superoxide dismutase activities in the lung tissue. The results indicate that; 1) VE appears to be necessary for the prevention of lipid peroxidation in BLM-induced oxidant lung injury, 2) VE deficiency produces a large number of free radicals at the early stage after BLM treatment, and might induce protease-antiprotease imbalance within the lung, which probably causes an emphysematous change in the BLM-treated lung at a late stage after BLM administration.

Animals↗
PubMed1989

Induction of cross-fertilization between sea urchin eggs and starfish sperm by polyethylene glycol treatment.

Cross-fertilization between sea urchin eggs (Strongylocentrotus nudus) and starfish sperm (Asterina pectinifera) was induced by treatment with polyethylene glycol (PEG). Without treatment with PEG, the denuded egg surface (jelly coat- and vitelline coat-free) engulfed the head of acrosome-reacted sperm; however, sperm penetration did not occur [Kyozuka and Osanai, 1988]. When these eggs were exposed briefly to PEG (molecular weight 3,000) in seawater, the sperm entered the egg by membrane fusion. Cortical granules were discharged, and embryogenesis began following sperm penetration. PEG did not induce parthenogenesis in Strongylocentrotus eggs. Egg activation is thus closely linked with gamete membrane fusion.

Acrosome↗
PubMed1989

Structural and functional polarity of starfish blastomeres.

The cortex of the blastomeres of Asterina pectinifera are structurally polarized so that some kinds of granules in the cortex, which can be stained vitally with Nile blue (Nile blue-positive granules, NBGs), and microvilli were distributed mainly in the apical region. The blastomeres always faced the adjoining blastomeres and blastocoel with the NBG-free, smooth region during embryogenesis. To confirm whether such blastomeres are functionally polarized, we rotated one of the blastomeres in the 2-cell-stage embryo so that it faced the other with the NBG-containing region. As a result, all embryos developed into twin or partitioned blastulae. This shows that the blastomeres are functionally polarized and have to orient the basal cortex toward the inner side of the embryo in order to be integrated into a blastula together with the others. The cortical polarity was formed and maintained even in blastomeres of dissociated embryos. In such blastomeres the cleavage furrows were formed along the axis of polarity. When the blastomeres began to adhere closely to each other at the 256-cell stage, only the NBG-free (basal) region acquired adhesiveness. These facts make it possible to infer why the correct apicobasal orientation of blastomeres is necessary for embryonic integration, without considering intercellular communication during the cleavage stage.

Animals↗
PubMed1988

Fertilization cone formation in starfish oocytes: the role of the egg cortex actin microfilaments in sperm incorporation.

The process of sperm incorporation into starfish (Asterias amurensis) oocytes was examined by electron and fluorescence microscopy. The fertilization cone began to form at the place where the acrosomal process fused with the egg surface and developed into an inverted conical mass containing a small amount of electron-dense cytoplasm. Microfilaments, which stained with NBD-phallacidin, were detected in the fertilization cone. Microvillar protrusions from the fully grown fertilization cone engulfed the sperm head outside the fertilization membrane. The sperm organelles were incorporated into the egg cortex with the absorption of the protrusions. Cytochalasin B inhibited sperm incorporation, fertilization cone formation, and actin filament organization. It is suggested that the development and reduction of the fertilization cone, which depend on the functioning of microfilaments, are necessary for sperm incorporation in starfish.

Actin Cytoskeleton↗
PubMed1988

Phagocytosis of sperm heads lacking the acrosomal process by unfertilized starfish oocytes.

In sperm of the starfish Asterina pectinifera, the acrosomal process and the flagellum were mechanically separated from the sperm head with a disperser. The sperm head fraction was then used to examine the direct interaction between the sperm head and the egg surface. Sperm heads lacking the acrosomal process and the flagellum did not fertilize oocytes, even after removal of the vitelline coat. Transmission electron microscopy showed that each denuded oocyte engulfed the sperm head without gamete membrane fusion. The sperm-engulfing response, similar to phagocytosis, was induced without the mediation of the acrosomal process. The present results suggest that the process of sperm incorporation consists of two independent events, acrosomal process-egg surface fusion and the phagocytotic movement of the egg surface.

Acrosome↗
PubMed1988

Sperm-engulfing response of sea urchin egg surfaces inseminated with acrosome-reacted starfish sperm.

Sperm-egg interaction was examined in two interclass combinations of sea urchin (Strongylocentrotus nudus and Hemicentrotus pulcherrimus) eggs and starfish (Asterina pectinifera and Asterias amurensis) sperm. Cross-fertilization was unsuccessful between these combinations. When the vitelline coat-free sea urchin eggs were mixed with acrosome-reacted starfish sperm, the elongated microvilli on the egg surface wrapped the sperm head. This sperm-engulfing response observed on the denuded egg surface was induced only in sperm immediately after initiation of the acrosome reaction. Further fertilization events, such as gamete membrane fusion or discharge of cortical granules, did not proceed. These observations suggest that acrosome-reacted sperm can induce a local response on the heterologous egg surface, that is independent of gamete membrane fusion and egg activation.

Acrosome↗
PubMed1988

The effect of cigarette smoke on bleomycin-induced pulmonary fibrosis in hamsters.

To investigate the effect of cigarette smoke on the development of bleomycin (BLM)-induced pulmonary fibrosis in hamsters, four experimental groups were studied: a control group (C), a cigarette smoke-inhaled group (T), a BLM-administered group (B), and a cigarette smoke-inhaled plus BLM-administered group (TB). Groups T and TB were exposed to sidestream smoke of cigarettes for 30 min/day, 5 days/wk. Groups B and TB were administered 0.5 mg BLM hydrochloride per 100 g body weight endotracheally once on day 30 (Day 0) after housing start. Quantitative morphometry of the lungs revealed that Group TB showed less lung fibrotic change compared with Group B, but based on qualitative observation, the fibrotic lesions of Group TB were intermingled with slight emphysematous changes. Neutrophils in bronchoalveolar lavage fluid were remarkably increased in both the groups, with a peak on Day 1, but the increase in Group TB lasted longer. Alveolar macrophages were increased in both smoking groups (T and TB) compared to the non-smoking groups (C and B). These results suggest that cigarette smoke reduces BLM-induced lung fibrotic changes; however, it simultaneously causes derangement of alveolar architecture. The persistence of increased neutrophils in the early phase after BLM accompanied by exposure to cigarette smoke may play an important role in the mechanism by which smoke ameliorates the effect of BLM.

Animals↗
PubMed1987

Bioelectric responses of sea urchin eggs inseminated with oyster spermatozoa: a sperm evoked potential without egg activation.

Multiple oyster spermatozoa can enter sea urchin eggs with or often without fertilization membrane formation (Osanai and Kyozuka, 1982). In the present work, electrical responses of sea urchin (Temnopleurus hardwicki) eggs inseminated with oyster (Crassostrea gigas) sperm were examined and correlated to the failure of monospermy and egg activation. With diluted sperm, a transient depolarization of the membrane with a constant pattern appeared repeatedly and discretely, and the depolarizations (sperm evoked potentials, SEPs) were not associated with fertilization membrane elevation. With dense sperm, the SEPs occurred consecutively, and sometimes an assembled consecutive depolarization was followed by an activation potential associated with cortical granule discharge. When the membrane potential was artificially held at positive levels, the frequency of SEPs was strongly suppressed but not completely blocked. The present results indicate that an individual heterologous spermatozoon neither produces a depolarization sufficient to block additional sperm entry, nor stimulates egg activation, and that simultaneous entries of multiple heterologous spermatozoa, as possibly reflected by the assembled consecutive depolarizations, induce cortical granule discharge and egg activation.

Animals↗