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Biomedical subjects

M Okayama

Publications and source records attributed to M Okayama.

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

Highly sulfated proteochondroitin sulfates synthesized in vitro by rat glomeruli.

A previous report from this laboratory (Kobayashi, S., Oguri, K., Kobayashi, K. and Okayama, M. (1983) J. Biol. Chem. 258, 12051-12057) indicated that isolated rat glomeruli synthesized three species of sulfated glycoconjugates in vitro, namely, sulfated glycoproteins, proteoheparan sulfates and proteochondroitin sulfates. In the present study, the proteochondroitin sulfates, which showed the greatest incorporation of [35S]sulfate among the three sulfated glycoconjugates, were isolated and characterized. Radiolabeled tissue proteochondroitin sulfates were clearly separated on Sepharose CL-6B into three components with partition coefficients (Kd) of 0.16, 0.22 and 0.58, and medium proteochondroitin sulfates were separated into two components with Kd values of 0.33 and 0.62. When the chondroitin sulfate chains released by alkaline borohydride treatment were analyzed by digestion with chondroitinase AC-II, chondroitinase ABC, chondro-6-sulfatase and chondro-4-sulfatase, the results showed that all the samples contained glucuronosyl-N-acetylgalactosamine (chondroitinase AC-II-susceptible sequences, 72-86%) and iduronosyl-N-acetylgalactosamine (chondroitinase ABC-susceptible sequences, 14-28%), containing 4-sulfated N-acetylgalactosamine (50-70%) and 4,6-disulfated N-acetylgalactosamine (30-50%). On two-dimensional electrophoresis on cellulose acetate, all samples gave a single spot which closely coincided with chondroitin sulfate E of squid cartilage in electrophoretic mobility. These results indicated that the chains were highly sulfated chondroitin sulfates containing glucuronic acid and iduronic acid residues.

Animals↗
PubMed1984

Bronchodilator effect of sublingual isosorbide dinitrate in asthma.

The bronchodilating effect of 5 mg sublingual isosorbide dinitrate (ISDN) was studied in 10 patients with bronchial asthma, using the double-blind randomised cross-over method with matched placebo. In a further 20 asthmatics the effect of sublingual ISDN was compared with that of metaproterenol given by a metered dose inhaler to a total dose of 2.25 mg, again using the cross-over method. The forced oscillation method was used to measure respiratory resistance (Rrs) and spirometry was used to measure vital capacity (VC) and forced expiratory volume in one second (FEV1). 5 minutes after administration of ISDN Rrs had decreased (p less than 0.05) and VC (p less than 0.01) and FEV1 (p less than 0.01) were significantly increased. The changes were still present after 15, 30 and 60 min. The placebo had no significant effect. ISDN increased FEV1 less than metaproterenol, and the difference between them was statistically significant (p less than 0.05). However, there was no significant difference between ISDN and metaproterenol in the improvement in Rrs and VC. Of the total of 30 patients, 11 experienced headache and 4 had transient hypotension after ISDN administration. These side effects subsided spontaneously. It was concluded that sublingual ISDN had a bronchodilating effect in stable asthmatics.

Adult↗
PubMed1984

Interaction between histamine and vagal stimulation on tracheal smooth muscle in dogs.

We examined the interaction between histamine and vagal efferent activity on airway smooth muscle reactivity in 11 anesthetized vagotomized dogs using an isolated closed segment of the intrathoracic trachea filled with Tyrode solution under an isovolumetric condition. Intratracheal pressure change was measured as an index of tracheal smooth muscle tone. The administration into the tracheal segment of histamine (0.1 or 1.0 mg/ml) in six dogs and methacholine chloride (0.001 or 0.01 mg/ml) in the other five dogs elevated intratracheal pressure by about 5 cmH2O. The electrical stimulation of the peripheral ends of both of the cut cervical vagus nerves in the presence of histamine produced significantly greater responses than the additive responses of these two stimuli applied individually (two-way analysis of variance, P less than 0.025). However, the combined effects of vagal stimulation and methacholine were not significantly different from the additive responses of these two stimuli applied individually. The average values of intratracheal pressure elevated by the combined effects of vagal stimulation and histamine were significantly higher than those obtained by the combination of vagal stimulation and methacholine (two-way analysis of variance, P less than 0.01). This suggests that histamine potentiates tracheal smooth muscle reactivity to electrical vagal stimulation, which may contribute to the hyperreactivity observed in patients with asthma.

Animals↗
PubMed1983

Isolation and characterization of proteoheparan sulfate synthesized in vitro by rat glomeruli.

Glomeruli isolated from rat kidney were incubated with [14C]glucosamine and [35S]sulfate. Linear incorporation of [14C]glucosamine into total glycosaminoglycans was observed during incubation up to 24 h. More than 95% of the 35S-labeled sulfated glycoconjugates were extracted from the tissue with 4 M guanidine HCl, 50 mM sodium acetate, pH 6.0, and 0.5% Triton X-100, and separated clearly on DEAE-Sephacel into three major fractions, i.e. sulfated glycoprotein (11% of the total radioactivity), proteoheparan sulfate (33%), and proteochondroitin sulfate (38%) fractions. The molecular weight of the 35S-labeled proteoheparan sulfate thus isolated was estimated to be about 185,000, whereas that released into the medium was estimated to be about 87,000. When the 35S-labeled heparan sulfate isolated on Sephadex G-75 after mild alkaline borohydride treatment was digested with a combination of heparitinase and heparinase, approximately 70% of the radioactivity was converted to 2-acetamido-2-deoxy-4-O-(alpha-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D- glucose.

Animals↗
PubMed1983

Characterization of a novel ceramide octasaccharide isolated from whole tissue of a fresh-water bivalve, Corbicula sandai.

A novel glycosphingolipid containing two mannose residues, provisionally named GL-1 in a previous paper (Itasaka, O. and Hori, T. (1979) J. Biochem. 85, 1469-1481), was isolated from whole tissue of a fresh-water bivalve, Corbicula sandai, and the structure of the glycolipid was determined to be: Galp4Me(beta1 more than 3)GalpNAc(beta1 more than 3)Fucp(alpha1 more than 4)GlcpNAc(beta1 more than 2)Manp(alpha1 more than 3)(Xylp(alpha1 more than 2))Manp(beta1 more than 4)Glcp(beta1 more than 1)Cer. Glycosphingolipid-1 seems to be a biosynthetic precursor of glycosphingolipid-3, because they have an identical octasaccharide structure, except for the presence of an aminoethylphosphoryl residue in glycospingolipid-3. However, in contrast to glycosphinogolipid-3, glycosphingolipid-1 has a more complex ceramide pattern. This fact suggests that glycosphingolipid-1 as isolated is not a degradation product of glycosphingolipid-3, and it can be presumed that the restricted molecular species of glycosphingolipid-1 which has the same ceramide constitution as glycosphingolipid-3 may be utilized preferentially for glycosphingolipid-3 biosynthesis.

Animals↗
PubMed1983

Increased synthesis of hyaluronic acid by mouse mammary carcinoma cell variants with high metastatic potential.

Variant subpopulations of FM3A mouse mammary carcinoma cells that have increased lung-colonizing potential were obtained previously by sequentially harvesting pulmonary metastases, culturing their cells in vitro, and reestablishing the metastases in vivo. In the present study, glycosaminoglycan production by the parental and variant cells was studied after metabolic labeling of cultures by [14C]glucosamine for 24 hr. Analysis of the products indicated that the rate of incorporation of the labeled precursor into hyaluronic acid in the high-metastatic variant cells was 27 to 54 times the rate in the low-metastatic variant cells and that the increase in hyaluronic acid synthesis was not associated with an increase in the rate of synthesis of other glycosaminoglycans. Both the cell layers and media of high-metastatic variants contained a much higher proportion of radioactivity in hyaluronic acid than did the corresponding fractions of low-metastatic cell lines. The results provide a basis for further investigation of the potential role of hyaluronic acid in control of the behavior of epithelial tumor cells during metastasis.

Animals↗
PubMed1982

Isolation and partial characterization of sulfated glycoproteins synthesized by corneal epithelium.

The corneal epithelia isolated from 19-day-old chick embryos were incubated with [35S]sulfate and [3H]glucosamine. More than 95% of the isotope-labeled sulfated glycoconjugates were extracted with 4 M guanidine/HCl, 50 mM sodium acetate, pH 6.0, and 0.5% Triton X-100 and separated on DEAE-Sepharose CL-6B into two major fractions, i.e. sulfated glycoprotein and sulfated proteoglycan fractions. Mild alkali treatment of the sulfated proteoglycan fraction and characterization of the sulfated glycosaminoglycans enabled the identification of heparan sulfate ([35S], 81%; [3H], 91%) and chondroitin sulfate ([35S], 19%; [3H], 9%). Fractionation of the sulfated glycoprotein fraction on Sepharose CL-6B resulted in the separation of four sulfated glycoproteins with apparent molecular weights of 70,000, 130,000, 280,000, and over 2,000,000. The products of alkaline borohydride treatment of the sulfated glycoproteins separated into three fractions on Sephadex G-75, two fractions contained sulfated oligosaccharides, and the third one contained inorganic sulfate and N-acetyl-galactosaminitol. Incorporation of [35S]sulfate into higher molecular weight fraction of the two fractions was selectively inhibited by tunicamycin, whereas that incorporated into the smaller molecular weight fraction was not inhibited by the drug and, rather, was activated. These results suggest that the former contains N-glycosidically linked sulfated glycopeptides, and the latter is derived from O-glycosidically linked sulfated oligosaccharide side chains.

Animals↗
PubMed1982

Isobaric force-velocity relationship of in situ canine trachealis muscle.

We measured the force-velocity relationship of the in situ trachealis muscle during vagal stimulation in six anesthetized dogs. The trachea, about 10 cm in length, was transected above the carina and left in situ with its blood supply intact, and its cut ends artificially closed. The lung was ventilated by a respiratory. First the vagal nerves were electrically stimulated to induce isometric contractions which resulted in an increase in tracheal pressure; then the tracheal volume was reduced to a rate (velocity) which kept the tracheal pressure constant at a given level (force). The force-velocity curve was hyperbolic. Using Hill's equation, we calculated the values of P0 (the maximum force at 10, lo being the trachealis muscle length at which the maximum active tension develops) and Vmax (the maximum velocity at zero afterload). They were P0 = 0.85 +/- 0.20 kg/cm2 and Vmax = 0.08 +/- 0.02 l0/s. We concluded that both force and velocity of the trachealis muscle in situ exhibited lower values than those in vitro.

Animals↗
PubMed1978

Primary familial amyloidosis with vitreous opacities. Report of an autopsy case.

A 41-year-old Japanese male with a new type of primary familial amyloidosis was reported. The patient developed vitreous opacities, and later, disturbances in the gastrointestinal and nervous systems. At autopsy, amyloid was observed in the vitreous and the retinal vessels. There were extensive cerebral infarcts and heavy meningo-vascular amyloid deposition. Although the postmortem study revealed slight peripheral nerve degeneration in the lower extremities secondary to amyloid deposition, there was no clinical evidence of polyneuropathy.

Adult↗
PubMed1978

Primary amyloidosis with familial vitreous opacities: an unusual case and family.

Peripheral neuropathy was not found even six to ten years after the onset of visual symptoms in a family with primary amyloidosis, except in the propositus at the terminal stage. The propositus had mainly ocular and CNS involvement. An ocular manifestation, the vitreous opacity, was the only involvement in the family members, in spite of the long clinical course. This family may have a different type of familial primary amyloidosis from that previously reported.

Adult↗
PubMed1977

Cellular transformation and differentiation. Effect of Rous sarcoma virus transformation on sulfated proteoglycan synthesis by chicken chondrocytes.

Incorporation of sulfate into sulfated proteoglycans by isolated chicken chondrocytes was inhibited up to 74% by transformation with the Rous sarcoma virus, and a similar inhibitory effect was observed on acetate incorporation into chondroitin sulfate. Slower sedimenting sulfated proteoglycans appear after the viral transformation. The ratio of chondroitin 4-sulfate to chondroitin 6-sulfate in these slower sedimenting sulfated proteoglycans was different from that of normal chondrocytes, but the chain lengths of sulfated glycosaminoglycans produced by normal chondrocytes and transformed chondrocytes were not significantly different. Chondrocytes were also infected with a temperature-sensitive mutant of RSV, ts LA24, which has a temperature-sensitive lesion in the transforming gene. Hyaluronic acid production by these cells was increased, and the slower sedimenting sulfated proteoglycan was produced only at the permissive temperature.

Acetates↗
PubMed1977

Transformation of chicken chondrocytes by Rous sarcoma virus.

Chicken chondrocytes isolated from 11-day-old chicken vertebrate cartilage were transformed by Rous sarcoma virus ts LA24 of the Prague strain as well as by the wild-type Prague strain of Rous sarcoma virus. The morphology of chondrocytes transformed by Rous sarcoma virus ts LA 24 was dependent on the temperature, and the change was reversible. A similar but irreversible change in morphology was observed with chondrocytes transformed by wild-type virus. Hyaluronic acid production and deoxyglucose transport were markedly increased in the transformed chondrocytes. A marked increase of labeled acetate incorporation was observed with the transformed chondrocytes. In contrast to the normal chondrocytes, the labeled hyaluronic acid synthesized by the transformed chondrocytes was mostly released into the culture medium.

Animals↗