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Biomedical subjects

M Okuno

Publications and source records attributed to M Okuno.

At least 127 records · Page 7Linked to original sources
PubMed1994

Fibroblast attachment to Arg-Gly-Asp peptide-immobilized poly(gamma-methyl L-glutamate).

The attachment of MRC-5 human fibroblasts was investigated on poly(gamma-methyl L-glutamate) (PMLG), and upon cell adhesion peptides Arg-Gly-Asp-Ser (RGDS)- and Gly-Arg-Gly-Asp-Ser (GRGDS)-immobilized PMLG (RGDS-PMLG and GRGDS-PMLG). The peptides were immobilized by their N-terminal amine to activated PMLG surfaces. Prior to peptide immobilization, the aminolysis of PMLG surfaces was performed with hydrazine hydrate (HA), ethylenediamine (EDA), and hexamethylenediamine (HMDA) and was followed by the activation with hexamethylene diisocyanate. Surface characterization of these films was carried out by means of a Fourier transform IR (FT-IR) spectrometer equipped with an attenuated total reflectance (ATR) attachment. The amount of immobilized RGDS could be controlled by the reaction time of the aminolysis. The effects of HA, EDA, and HMDA as a spacer on the cell attachment were also investigated, and it was suggested that a longer spacer promoted the cell attachment via specific receptor-ligand interaction.

Amino Acid Sequence↗
PubMed1994

Analysis of flagellar bending in hyperactivated hamster and mouse spermatozoa.

Flagellar bending was analysed using photographs of hyperactivated hamster and mouse spermatozoa. The flagellar waveform consists of several bends; the centre of each bend was therefore located on the flagellum, and the angle of the bend measured. The direction of the bend was determined by using the asymmetry of hook-shaped head to assess the asymmetry of flagellar waveform. The bend that occurred in the same direction as the curve of head was defined as the reverse bend and the bend in the opposite direction as the principal bend. In hamster spermatozoa, flagellar bending was asymmetric to the direction of the reverse bend after incubation for 5 min. After incubation for 4 h the asymmetry had increased, as the angles of the reverse bends had increased in all regions of the flagellum but the principal bend had not. In mouse spermatozoa incubated for 5 min, flagellar bending was relatively symmetric. In the hyperactivated mouse spermatozoa incubated for 3 h, the angle of the principal bend increased in the distal region and those of the reverse bends increased in almost all regions of the flagellum. Since the increase in the reverse bend was relatively high, flagellar bending became asymmetric to the direction of the reverse bend as in hamster spermatozoa. These increases in asymmetry were also evident in the measurement of the total changes in angular direction between the proximal and distal end of flagella in both species. The increase in asymmetry could provide an explanation for the changes in the motility patterns seen in spermatozoa after the onset of hyperactivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Modulation of collagen synthesis and degradation by retinoids and cytokines in 3T3 L1 preadipocytes.

We previously observed that a retinoid analog can protect against liver parenchymal damage and liver fibrosis, whereas it accelerates liver fibrosis which is not accompanied by any parenchymal damage. To elucidate these conflicting effects, we examined the effects of retinoid in 3T3 L1 preadipocytes as a model of liver stellate cells. Retinoids, including all-trans retinol, all-trans and 9-cis retinoic acids, enhanced the cell growth and the expression of the type I procollagen gene as well as its peptide synthesis, while reducing collagenase activities. Although no retinoid enhanced the transforming growth factor (TGF)-beta 1 mRNA, retinoids may stimulate collagen production through activating TGF-beta, as was recently reported. These results help explain the observation in the liver fibrosis model with no parenchymal damage. In contrast, we also found that interferon (IFN) alpha beta and gamma inhibited cell growth and down-regulated markedly type I procollagen as well as TGF-beta 1 mRNA, suggesting that they suppress by acting directly on extracellular matrix-producing cells.

3T3 Cells↗
PubMed1994

[A cohort study on dental caries in infants].

A cohort study was performed to determine what techniques are effective in dental caries prevention in infants. Subjects were 878 children aged 18 months, who visited the Gifu-shi Central Public Health Center to receive the medical health check and who were found to be dental caries free. The subjects received both 18 months and 3 years old dental health examinations which included data on incidence of dental caries and oral hygiene conditions (plaque score). Information on the children's between-meals eating habits and mother aided daily tooth brushing habits were obtained from their mothers. Caries incidence was 31.5% and 43.3% in children with good and poor oral hygiene conditions, 30.9% and 38.5% in children with and without daily brushing habits, and 41.0% and 29.2% in children with and without between-meals eating habits, respectively. Logistic regression analysis indicated that oral hygiene conditions and eating habits between meals were more important than mother aided daily tooth brushing.

Child, Preschool↗
PubMed1993

Case of Williams elfin facies syndrome with pulmonary artery sling.

We report the presence of pulmonary artery sling in a 4-year-old girl with the Williams elfin facies syndrome. A history of heavy and persistent wheezing during the first few months of life, associated with the current presentation of heart murmur and pulmonary stenosis, led us to investigate the presence of pulmonary artery sling. Both pulmonary artery sling and cardiovascular anomalies in Williams elfin facies syndrome have previously been linked to developmental anomalies of the 6th aortic arch. This appears to be the second reported case of this rare combination of anomalies.

Child, Preschool↗
PubMed1993

Roles of pH and cyclic adenosine monophosphate in the acquisition of potential for sperm motility during migration from the sea to the river in chum salmon.

In the natural process of the migration of chum salmon from the sea to the river, spermatozoa moved from the testis to the sperm duct, and the pH value of seminal plasma, concentration of cyclic adenosine monophosphate (AMP) in the sperm cells, and potential for sperm motility increased. Cyclic AMP levels and the potential for motility gradually increased when testis spermatozoa with no capacity for movement were incubated in the artificial seminal plasma of which the pH was much the same as, or higher than, the pH of natural seminal plasma from the sperm duct. Such correlation in motility, pH, and cyclic AMP suggests that the increases in seminal pH and intracellular cyclic AMP level during passage of spermatozoa from the testis to the sperm duct cause the acquisition of potential for motility. Motility of testicular spermatozoa demembranated with Triton X-100 was very low in fish caught in the sea, while motility of spermatozoa from the posterior portion of the sperm duct was much higher in fish caught in the river. Furthermore, nondemembranated, intact spermatozoa showed a lag in the timing of the acquisition of potential for motility vs. demembranated spermatozoa: The demembranated sperm exhibited the potential earlier than the nondemembranated sperm. These data suggest that increase in activity of the motile apparatus, the axoneme, is a prerequisite, in part, for the acquisition of sperm motility, whereas the development of some function of the plasma membrane also contributes to this phenomenon.

Animals↗
PubMed1993

Multiple activation of mouse sperm motility.

To investigate the activation mechanism of mouse sperm motility, the intact sperm in various activities were further investigated after demembranation. When dry sperm was diluted into sucrose solution, the sperm exhibited low motility with the swimming velocity of 13.5 +/- 3.8 microns/s and the beat frequency of 1.5 +/- 0.4 Hz. The demembranated sperm were immotile in the reactivation solution lacking cAMP. Meanwhile, when dry sperm was diluted into the solution containing either high concentration of NaCl or Ca2+, they exhibited the beat frequency of about 9 Hz. The demembranated ones exhibited the intermediate motility in the absence of cAMP. When dry sperm were diluted into the sucrose solution containing HCO3-, the sperm exhibited a vigorous motility with the swimming velocity of 181.2 +/- 10.1 microns/s and the beat frequency of 11.3 +/- 1.2 Hz. The demembranated sperm exhibited the high reactivation motility (90%) and flagellar beat frequency (9 Hz) in the absence of cAMP. These values were almost equivalent to those obtained in the demembranated sperm pretreated with sucrose or Ca2+ or NaCl and reactivated in the presence of cAMP. The activation induced by bicarbonate was considered complete in comparison with the activation by Ca2+ or NaCl. It was likely that the activation of mouse sperm motility took multiple states.

Animals↗
PubMed1993

The sliding of the fibrous sheath through the axoneme proximally together with microtubule extrusion.

When activated mouse sperm were treated with Triton X-100 and dithiothreitol at pH 9.0, the plasma membrane and mitochondrial sheath of the sperm flagella were removed. These mitochondrion-free demembranated sperm flagella were perfused with Mg-ATP and trypsin to induce the sliding disintegration of microtubules from the axoneme. We observed that when the doublet microtubules associated with outer dense fibers extruded from the axoneme, the fibrous sheath (FS) was pulled proximally to the connecting piece from the annulus of the sperm flagellum accompanying the extrusion of microtubules. Furthermore, the FS sliding was cAMP-dependent and the maximal sliding velocity was about 3.7 +/- 0.1 microns/s in the presence of 1.0 mM ATP at 37 +/- 1 degrees C. Since the FS projected inward and attached opposite doublet microtubules 3 and 8 in the principal piece, our observation showed the possibility that doublet 3 and/or 8 participated in FS sliding.

Adenosine Triphosphate↗
PubMed1993

Effect of endothelin 1 on ion transport in isolated rat colon.

BACKGROUND: Endothelin may play a significant role in the regulation of gastrointestinal function because it has a variety of biological activities and because endothelin-like immunoreactivity as well as its specific binding sites have been found in the gastrointestinal tract. This study investigated the secretory effect and mechanism of action of endothelin 1 in mammalian large intestine. METHODS: Distal colonic segments from Sprague-Dawley rats were stripped of their muscle layers and mounted in Ussing chambers. The effects of endothelin 1 on short-circuit current in rat colonic mucosa were studied in the absence or presence of specific inhibitors. Transmural unidirectional 22Na+ and 36Cl- fluxes and endothelin 1-induced prostacyclin release were also measured. RESULTS: Serosal addition of endothelin 1 evoked a sustained increase in short-circuit current that was significantly reduced by tetrodotoxin or atropine, and virtually abolished by a selective endothelin A receptor antagonist (BQ-123), furosemide, piroxicam, d,I-verapamil, or removal of serosal calcium. Hexamethonium, amiloride, diphenhydramine, or a specific platelet-activating factor antagonist (CV-6209) did not influence the response to endothelin 1. Endothelin 1 significantly decreased net sodium and net chloride absorption and induced a marked increase in prostacyclin release from the serosal surface of stripped colonic mucosa. CONCLUSIONS: Endothelin 1 has a secretory effect in rat colon. Its action seems to be mediated by cyclo-oxygenase products and enteric nerves via the activation of an endothelin A receptor.

Animals↗
PubMed1993

Scheduled feeding caused activation of dopamine metabolism in the striatum of rats.

The effects of a time-restricted feeding schedule on dopamine (DA) release and its metabolites output in the striatum of freely moving rats were studied. Rats had access to food for only 2 h daily for 7 successive days. On the 1st or 7th day, the extracellular concentrations of DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the ventrolateral striatum were measured by in vivo brain microdialysis during 2 h of exposure to food-related stimuli followed by 2 h of access to food. Extracellular concentrations of DA and its metabolites did not change during the period of exposure to food-related stimuli or during feeding on the 1st day. On the 7th day, extracellular DOPAC and HVA concentrations increased significantly during 2 h of feeding, but not during exposure to food-related stimuli, compared with basal levels. Extracellular DA concentration did not change significantly. These results indicate that scheduled feeding caused activation of DA metabolism in the ventrolateral striatum and facilitate feeding-related motor activity in feeding behavior.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1993

No effects of smoking or drinking habits on salivary amylase.

Nonstimulated and expectorated whole saliva was collected from 166 males and 180 females. To investigate biological effects of smoking and drinking habits on digestive functions in healthy populations, salivary total proteins and amylase activity were determined in the saliva samples. Sex differences in the salivary components were not found. Neither of the two habits had any significant influences on salivary proteins or amylase activity in the subjects. Light to moderate uses of tobacco or alcohol may not influence basal components of saliva.

Adult↗
PubMed1993

Cell-attachment activities of surface immobilized oligopeptides RGD, RGDS, RGDV, RGDT, and YIGSR toward five cell lines.

Tetrapeptides, Arg-Gly-Asp-Ser (RGDS), Arg-Gly-Asp-Val (RGDV), and Arg-Gly-Asp-Thr (RGDT), respectively, appearing in the cell-attachment domains of fibronectin, vitronectin, and collagen, and pentapeptide Tyr-Ile-Gly-Ser-Arg (YIGSR) appearing in B1 chain of laminin, were synthesized by liquid-phase procedure. Bioactivities of RGD, RGDX (X = S, V and T), YIGSR, and YIGSR-NH2 as cell recognition determinants were investigated by cell-attachment test using these oligopeptides immobilized to ethylene-acrylic acid copolymer (PEA) film. The cell lines used were A431, NRK, CHO-K1, HeLa.S3, and RLC-16 cells. It was found that the residue X in RGDX plays an important role for cell-attachment activity of RGDX, and, regarding YIGSR, introduction of NH2 residue at the C-terminal of the pentapeptide enhances the cell-attachment activity.

Acrylic Resins↗
PubMed1993

[Clinical evaluation of a lung cancer-associated protein antigen, cytokeratin 19 fragment: I. Radioimmunoassay and its fundamental character for clinical laboratory measurement].

Serum level of cytokeratin 19 fragment; which is a tumor associated antigen of lung cancer; was detected by the radioimmunometric assay. Reliability for clinical laboratory measurement was investigated. Detective range of cytokeratin 19 fragment was 0-50 ng/ml and the results including reproducibility, linearity of the data from diluted standard samples, was good enough for laboratory practice use. Although, influence of high concentration of CA19-9 over cytokeratin 19 fragment assay was suspected, there was no correlation between amount of added the antigen to data of cytokeratin 19 fragment. So direct cross reactivity of cytokeratin 19 fragment antibody to CA19-9 seemed less possible. As inhibitory effect of samples which contained over 100 ng/ml of cytokeratin 19 fragment on assay was observed due to antigen excess, evaluation by diluted sample was necessary for the samples that showed over detective limit.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1993

[Clinical evaluation of a lung cancer-associated protein antigen, cytokeratin 19 fragment: II. Radioimmunoassay and effect of aging and smoking over serum level of normal individuals].

Serum level of cytokeratin 19 fragment which is a tumor associated antigen of lung cancer was detected by the radioimmunometric assay. Effect of smoking and of aging on serum reference value was analyzed over 331 normal individuals. Serum cytokeratin 19 fragment level of smokers, mean 0.89ng/ml, was higher than that of non-smokers, mean 0.70ng/ml although there was no statistical meaning over the difference. And there was tendency to increase of cytokeratin 19 fragment level with aging. Mean + 2SD of cytokeratin 19 fragment of normal was 2.17ng/ml. Clinico-epidemiological specificity of cytokeratin 19 fragment on normal individuals was discussed.

Adult↗
PubMed1993

[Analysis of bone loss with aging and menopause--using digital image processing].

To study bone loss relationships to aging and menopause, cross-sectional bone mass measurements by digital image processing (DIP method), and menopause information collected by questionnaire, were analyzed on 291 women who live in Tsukude village. The results are as follows. 1) The mean DIP values (sigma GS/D, MCI) by age-stratified groups decrease with age after menopause. The rate of bone loss in sigma GS/D is almost constant, but in MCI it increases with aging. 2) In 30-year old and 40-year old age groups, the frequency distribution of DIP values is symmetrical and bell-shaped. But after the fifties the distribution is asymmetrical, with the mode of distribution deviated toward low bone mass. The change of mode with aging is larger than that of mean. This fact suggests that change of mean bone mass substantially underestimates actual bone loss from aging. 3) The change of the mean DIP values stratified by years elapsed since menopause is not especially large at start of menopause but becomes almost constant after menopause. DIP values reflect the bone loss from the aging rather than from menopause, and are beneficial to the study of bone loss in elderly women.

Adult↗