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Biomedical subjects

S Kasuga

Publications and source records attributed to S Kasuga.

At least 37 records · Page 2Linked to original sources
PubMed1996

Mitochondrial DNA 3394 mutation in the NADH dehydrogenase subunit 1 associated with non-insulin-dependent diabetes mellitus.

Mitochondrial DNA (mtDNA) mutation is associated with a subtype of non-insulin-dependent diabetes mellitus (NIDDM). We identified two homoplasmic mtDNA mutations at the positions of 3394 (T-C) and 3423 (G-T) in a NIDDM patient with clinical features of mitochondrial encephalopathy. The mtDNA 3394T-C mutation changed a conserved tyrosine to a histidine in NADH dehydrogenase subunit 1. The frequency of mtDNA 3994 T-C mutation was determined with Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) in general NIDDM patients and nondiabetic control subjects. The mutation was seen in 4.9% of NIDDM patients and 1.3% of nondiabetic controls. It is indicated that the mtDNA 3394 T-C mutation is associated with NIDDM in Japan.

Base Sequence↗
PubMed1995

Changes in calcium distribution in the utricular supporting cells of the guinea pig.

Changes in calcium distribution in cultured utricular supporting cells following streptomycin sulfate (SM) intoxication were investigated by means of an organ culture system using potassium pyroantimonate (PA) precipitation. PA precipitation showed that calcium ions are located in the otoconia and in the secretory granules of the supporting cells. Exposure of the supporting cells to SM increased the number of lysosomes and reduced the secretory granules in the cytoplasm. These lysosomes had many granules containing calcium ion. It is suggested that calcium secretion from the secretory granules was inhibited by SM and that this might lead to reduction of otoconia.

Animals↗
PubMed1995

Effect of streptomycin on the supporting cells of the utricular macula.

Morphological changes in utricular supporting cells in the guinea pig following streptomycin sulfate (SM) intoxication were investigated ultrastructurally in vitro, using an organ culture system. The intracellular structures of the supporting cells, such as the nucleus, mitochondria, and Golgi apparati were well preserved after 7 days in culture. After 10 and 14 days in culture, the supporting cells degenerated. The organ culture system was applied to ototoxicity studies on the supporting cells in utricular macula within 7 days after explanation. When the utricles were exposed to 3, 10 and 30 mg/ml of SM for 3 days, the number of granules in the supporting cells decreased markedly and the number of lysosomes increased daily. The lysosomes contained mitochondria, myeloid bodies, granules and vesicles. Acid phosphatase (AcPase) activity decreased in Golgi apparati and lysosomes. When the concentration of SM was reduced to 3 and 10 mg/ml, the damage to the supporting cells was less marked than that in cells exposed to 30 mg/ml. The supporting cells showed a dose-dependent response with respect to morphological damage. After 3 days culture with 30 mg/ml of SM, the specimens were subsequently cultured for 4 days in a medium without SM. After removal of SM from the medium, lysosomes decreased in number, and the granules and the endoplasmic reticulum showed a gradual increase. The AcPase activity was determined in both lysosomes and Golgi apparatus. This study revealed that the morphological changes in the supporting cells can be reversible.

Acid Phosphatase↗
PubMed1994

Pharmacokinetics of the garlic compound S-allylcysteine.

The pharmacokinetic behavior of S-allylcysteine (SAC), one of the biologically active transformation products from garlic, was investigated after oral administration to rats, mice, and dogs. SAC was rapidly and easily absorbed in the gastrointestinal tract and distributed mainly in plasma, liver, and kidney. The bioavailability was 98.2, 103.0, and 87.2% in rats, mice, and dogs, respectively. SAC was mainly excreted into urine in the N-acetyl form in rats; however, mice excreted both SAC and the N-acetyl form. The half-life of SAC was longer in dogs than in rats and mice.

Animals↗
PubMed1993

Three-dimensional observation of the Golgi apparatus in the vestibular (Scarpa's) ganglion cell.

Ultrastructure of the Golgi apparatus and GERL was observed three-dimensionally from the functional view point of lysosome formation. GERL directly continues with rough endoplasmic reficulum. There are at least two systems for lysosome formation, i.e. dependent and not dependent systems on the Golgi stack respectively. GERL also continues with a trans Golgi saccule, indicating that GERL is a part of the Golgi apparatus.

Animals↗
PubMed1991

Ultrastructural changes in aging rat tracheal gland.

Ultrastructural differences in the tracheal gland between young and aged rats were studied. Marked differences were observed in the serous cells between the young (8-17 week-old) and the aged (20-30 month-old) subjects. The secretory granules of the serous cells of the young subjects were homogeneously electron dense, whilst those of the aged subjects had a bizonal appearance. These bizonal granules contained abundant mucous material. The trans Golgi network of the aged rat serous cells was more developed and formed a fine meshwork in comparison with that of the young subjects. In the aged subjects, findings indicate alterations not only in the function of the Golgi apparatus including formation of secretory granules and addition of terminal sugars to the secretory protein but also the histochemical and ultrastructural properties of the secretory material. The changes in the Golgi apparatus are possibly responsible for depression of the tracheal host defense mechanism and might explain why various airway diseases increase with aging.

Aging↗
PubMed1990

Effects of secretory stimulation on the Golgi apparatus and GERL of rat tracheal gland cells.

The morphological and cytochemical changes of the Golgi apparatus and GERL of rat tracheal serous cells were studied after in vivo secretory stimulation with pilocarpine. Discharge of PAS-positive secretory granules had started within 30 min and complete discharge was finished within 2 h after stimulation. Reaccumulation of secretory granules became evident at 6 h and the volume of granules was similar to that of unstimulated control cells at 8 h. At 6 h after pilocarpine administration, acid phosphatase (AcPase) activity was markedly increased in GERL and immature secretory granules as compared to uninjected controls and this phenomenon continued 12 h after stimulation. GERL appeared to increase in extent and numerous continuities with immature granules were observed. Thiamine pyrophosphatase (TPPase) activity, normally present in trans Golgi saccules was not altered during the secretory cycle. At 2 h after stimulation, tubular structures of GERL, which also react to AcPase, were seldom observed. At 6 h, these structures were more numerous than those of control cells. These results demonstrate that, in rat tracheal serous cells, pilocarpine induces alteration of only GERL, and reconstitution followed by resynthesis of secretory granules is performed without participation of the Golgi stack.

Acid Phosphatase↗
PubMed1990

Three-dimensional observation of the Golgi apparatus in rat tracheal gland during the secretory cycle.

The purpose of the present work is three-dimensional clarification of the overall configuration of the Golgi apparatus in rat tracheal serous cells including the sequence of structural modification during the secretory cycle induced by pilocarpine. From the results of both transmission electron microscopy from the serial sections, and scanning electron microscopy using the osmium-DMSO-osmium method based on maceration in dilute osmium tetroxide, the overall configuration of the Golgi apparatus shows that the Golgi stacks are joined together to make an interconnected, single Golgi complex in a cell. Connections, not only between the TGN (trans Golgi network) and rough ER (endoplasmic reticulum), but also between rough ER and cis cisternae are observed. This finding offers alternative routes for movement of substances through the cellular endomembrane system. During the secretory cycle induced by pilocarpine injection, it is evidenced that the disappearance of the TGN is accompanied by rapid discharge of secretory granules and the reconstitution of the TGN is followed by reformation of secretory materials. The beginning of the reconstitution of the TGN is indicated by vesicular buds from the sacculotubular element. These results indicate that the TGN participates directly in membrane recycling and in formation of secretory granules.

Animals↗
PubMed1987

Effect of biosynthetic human epidermal growth factor on the synthesis and secretion of mucin glycoprotein from primary culture of rabbit fundal mucosa cells.

Biosynthetic human epidermal growth factor (Bh-EGF) induced dose-dependent synthesis and secretion of neutral mucin glycoprotein when the fundal cells isolated from rabbit stomach were cultured in serum-free medium containing Bh-EGF at concentrations as high as 10 to 100 ng/ml. At these high concentrations, Bh-EGF had no effect on the cell growth. In marked contrast, much lower concentrations from 0.1 to 1.0 ng/ml of Bh-EGF failed to stimulate mucin synthesis, but enhanced proliferation of the cells. Electrophoretic pattern of the mucin secreted from the cultured mucosal cells was very similar to that of the authentic mucin obtained from rabbit stomach. Maximal secretion of the mucin from the cells was observed at Hour 96 of the culture. Although fetal bovine serum (5%) and insulin (0.5 microgram/ml) also stimulated the mucosal cells, both in growth and in mucin synthesis and release, the enhancing activity of the mucin synthesized and released by Bh-EGF at a concentration of 100 ng/ml per microgram DNA of cultured cells was far superior to that of 5% fetal bovine serum and 0.5 microgram/ml insulin.

Animals↗
PubMed1987

Antifungal activity of ajoene derived from garlic.

The antifungal activity of six fractions derived from garlic was investigated in an in vitro system. Ajoene had the strongest activity in these fractions. The growth of both Aspergillus niger and Candida albicans was inhibited by ajoene at less than 20 micrograms/ml.

Antifungal Agents↗
PubMed1987

Long-latency growth-promoting activity of EGF when administered to mice at the neonatal stage.

The effect of biosynthetic human epidermal growth factor (Bh-EGF) as well as mouse EGF on postnatal development of mice of ICR strain was examined. Daily administration of Bh-EGF (0.01, 0.1, and 1.0 microgram X g body wt-1 X day-1) for 30 consecutive days postpartum caused a clearly dose-dependent increase in their body weight. Furthermore, in addition to the well-known premature eyelid opening and early tooth eruption, we have also observed precocious opening of the vagina among treated females. As far as the accelerated growth rate as reflected in their body weight gain was concerned, daily administration for only five consecutive days postpartum was just as effective as the above noted 30 consecutive daily injections. As to the precocious vaginal opening, however, the susceptible 5-day-period was found to be 14-18 days after the parturition. Some of those treated females also entered the estrous cycle precociously, a few days after the precocious opening of their vagina. The microscopic examination of various organs from treated males and females revealed no apparent pathological changes. As far as the above noted effects of EGF were concerned, Bh-EGF, which is xenogenic to mice, was as potent as mouse EGF.

Animals↗
PubMed1985

Biological effects of biosynthetic human EGF on the growth of mammalian cells in vitro.

The effects were examined of biosynthetic human epidermal growth factor (Bh-EGF) produced from cloned E. coli on DNA synthesis and all divisions of 13 different kinds of primary and established cell lines. Primary cultures of mammary epithelia, hepatocytes and stomach cells were strongly stimulated by EGF to undergo DNA synthesis in serum-free culture medium with concentrations of Bh-EGF as low as 0.1-10 ng/ml. In sharp contrast, 0.1-100 ng/ml of Bh-EGF failed to enhance thymidine incorporation into DNA when applied to established cell lines using the serum-free medium. Higher concentrations of Bh-EGF (30-100 ng/ml) promoted morphological changes only in hepatocytes, e.g., elongation, enlargement and projection of their cytoplasm. The above results were also obtained in mouse EGF (m-EGF). In our binding assay, Bh-EGF competed against [125I]-m-EGF with a one-fourth to one-fifth efficacy when compared with m-EGF. It was concluded that the in vitro biological activity of Bh-EGF was similar to that of m-EGF.

Animals↗