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Biomedical subjects

R Kobayashi

Publications and source records attributed to R Kobayashi.

At least 397 records · Page 22Linked to original sources
PubMed1986

The amino acid sequence of kinetensin, a novel peptide isolated from pepsin-treated human plasma: homology with human serum albumin, neurotensin and angiotensin.

A novel nonapeptide with neurotensin-like immunoreactivity was isolated from pepsin-treated human plasma by dialysis, ion-exchange chromatography and high performance reversed-phase liquid chromatography. The amino acid sequence was determined by automated gas-phase sequence analysis as Ile-Ala-Arg-Arg-His-Pro-Tyr-Phe-Leu. Sequence homology with human serum albumin and with the biologically active peptides neurotensin and angiotensin is demonstrated. The name proposed for this peptide is kinetensin.

Amino Acid Sequence↗
PubMed1986

Immunohistochemical studies on the GABAergic system in the rat supraoptic nucleus using the PAP method with an application of electron microscopy.

GABAergic neuronal profiles in the supraoptic nucleus of the rat were immunohistochemically identified by using a purified GABA antibody with the peroxidase-antiperoxidase method. The localization of GABA-like immunoreactivity in nerve terminals on the neurosecretory neurons was examined electron microscopically. A few small GABAergic neurons were found inside the supraoptic nucleus while only a very few medium-sized ones were detected in the perinuclear zone. Intrinsic, non-GABAergic small neurons covered by GABAergic neuropil were also detected. The neuropil with GABAergic axo-somatic synapses evenly encompassed unlabeled neurosecretory perikarya throughout the supraoptic nucleus. The GABAergic system seems to inhibit both vasopressin and oxytocin cells. In this area, glia cells showed clear outlines of unlabeled somata around counter-stained nuclei. Blood capillaries in the supraoptic nucleus were only slightly covered with a GABAergic neuropil. Electron microscopic observations demonstrated the presence of GABAergic axo-somatic symmetrical and axo-dendritic asymmetrical synapses on the neurosecretory neurons. GABA-like immunoreactivity was localized on the membranes of microtubules and synaptic vesicles, on the external membranes of the mitochondria, and on the inner leaf of the presynaptic sites. Numerous pairs of non-immunoreactive synapses were arranged along these immunoreactive synapses.

Animals↗
PubMed1986

[Intra-arterial chemotherapy of soft tissue sarcoma in children].

As to the treatment of soft tissue tumor in children, we have performed intraarterial infusion chemotherapy in 3 children, two of whom had rhabdomyosarcoma and one of whom had infantile fibrosarcoma, at Sapporo National Hospital. The former two patients had large and unresectable solid tumor. In the latter case, an uncommon disease of childhood, local excision was considered while sacrificing a significant degree of function in the affected part. We describe here these three cases and the effectiveness of this therapy. Intraarterial chemotherapy reduced the tumor remarkably and facilitated second-look surgery. Although transient hematuria, slight articular contracture and vasculitis were observed in each case as side effects during the therapy, they were only minimal and tolerable. Unfortunately, one patient relapsed 6 months after surgery, but two patients are still in good health without recurrence. According to the results of our study, we believe that this method can be effective for controlling unresectable primary malignant soft tissue tumor.

Antineoplastic Agents↗
PubMed1986

[Effects of cis-DDP in children with refractory malignant tumors].

Eighteen children with refractory malignant tumors were treated with cis-DDP. They included 10 neuroblastomas, 2 rhabdomyosarcomas, and one each of hepatoblastoma, yolk sac tumor, osteosarcoma and pinealoma. Of 7 cases treated only with cis-DDP, 2 were NC, 6 PD and none were CR or PR. Of 11 cases treated with cis-DDP combined with other agents, 7 were PR, 2 NC, 2 PD and none were CR. The major side effect of cis-DDP was renal toxicity, but this was not serious and only transient. Three cases were treated with the continuous intra-arterial infusion method. These included 2 neuroblastomas and one yolk sac tumor. This treatment was therefore highly effective for children with malignant tumors, and few side effects were observed.

Adolescent↗
PubMed1985

Isolation and partial characterization of canine epidermal growth factor/urogastrone.

Canine epidermal growth factor (EGF)/urogastrone was partially purified from dog urine by fractional precipitation with (NH4)2SO4, ion-exchange chromatography with DEAE-cellulose DE-52, gel filtration with Sephadex G-50, and a second DE-52 chromatography, to yield receptor-competing activity equivalent to 13 micrograms of standard mouse EGF/litre of starting urine. The purification was monitored by a competitive radioreceptor assay using fixed monolayers of A431 cells. The partially purified canine EGF/urogastrone demonstrated a growth-stimulating activity in 3T3 mouse fibroblast cells as potent as mouse EGF. Analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed one major peptide component with an Mr similar to that of mouse EGF, and two minor peptides of slightly higher Mr. The major peptide component was isolated after reduction and its amino acid composition was determined.

Amino Acids↗
PubMed1985

Determination of ABH secretor status by an electronic quantitation method.

Blood Group A and B substances in secretor (Se) and nonsecretor (se) salivas were tested by means of an electronic data processing-hemagglutinin-inhibition test (EDP-HAIT) with immunoglobulin M (IgM) isohemagglutinins. Besides a difference in quantity, the blood group substances in Se saliva showed high binding efficiencies compared with those in se saliva. EDP-HAIT with IgG isohemagglutinins proved no difference in the binding efficiencies of Se and se salivas. The determination of secretor status by EDP-HAIT with IgM isohemagglutinin was accurate because the conclusion was obtained based on two different quantitative results. Secretor status of some salivas in gargled water could be determined by comparing the binding efficiencies.

ABO Blood-Group System↗
PubMed1984

Sulfhydryl groups of aldosterone receptors from swine kidney.

Specific [3H]aldosterone binding activity in swine kidney cytosol was inactivated by pretreatment of the cytosol with monoiodoacetamide (pH 8.5), N-ethylmaleimide (pH 7.0), or 5,5'-dithiobis(2-nitrobenzoate) (pH 7.5). Dithiothreitol restored the specific binding activity inactivated by the nitrobenzoate, but not that inactivated with ethylmaleimide. Incubation of the cytosol with aldosterone prior to pretreatment with ethylmaleimide protected the receptors from inactivation. The rank order of steroids for the protection was: aldosterone greater than hydrocortisone greater than or equal to dexamethazone = progesterone greater than triamcinolone greater than estradiol. The initial velocity of the specific hormone binding could be determined by the binding reaction for 60 sec at 30 degrees. Double reciprocal plots of the initial velocity versus the hormone concentration with or without the nitrobenzoate showed a typical pattern of competition between the hormone and the inactivator. The results indicated the presence of functional sulfhydryl groups on the hormone binding sites of aldosterone receptors.

Aldosterone↗
PubMed1984

Different muscle-specific forms of rabbit skeletal muscle alpha-actinin.

The structures and functions of the two alpha-actinin isoforms [R. Kobayashi et al. (1983) Eur. J. Biochem. 133, 607-611] isolated from rabbit longissimus dorsi and psoas muscles were compared. One-dimensional and two-dimensional electrophoretic analyses showed that the two alpha-actinins were different from each other in their subunit chain weights and isoelectric points. The Stokes' radius of the longissimus dorsi and psoas alpha-actinins was 7.4 nm and 7.0 nm, respectively. The amino acid analyses showed that, although the two alpha-actinins are similar in their amino acid compositions, longissimus dorsi alpha-actinin contains more aspartic acid and isoleucine than psoas alpha-actinin but fewer glycine and valine residues. Analysis of the soluble tryptic peptides by two-dimensional mapping revealed that the two alpha-actinins had major differences. These data suggested that the two isoforms are the products of at least two different genes. Despite these differences, both alpha-actinins share a number of common properties. Both alpha-actinins contain a 55-kDa peptide resistant to trypsin. The two proteins show no differences in actomyosin turbidity assays. ATPase assays and F-actin binding assays of alpha-actinin activity. Immunological examination indicates that the two alpha-actinins share antigenic determinants in common.

Actinin↗
PubMed1984

Relationship between maximum active stress and contractile protein contents in the chronically obstructed ureter.

Maximum active stress and contractile protein contents of the dilated ureter were determined using the chronically obstructed rabbit ureter. Active length-tension curve was demonstrated for tissue strips obtained from normal and dilated ureters. In the normal ureter, maximum active stress of the strips was 10.4 +/- 2.04 X 10(4) dyne/cm.2 while the myosin and actin contents in the tissue were 6.05 +/- 0.44 and 15.46 +/- 1.96 mg./gm. tissue, respectively. Maximum active stress of the obstructed ureter varied from 5.1 X 10(4) to 19.0 X 10(4) dyne/cm.2 The amount of contractile protein in the obstructed ureter varied from 0.57 to 8.07 mg./gm. tissue for myosin and from 8.16 to 22.9 mg./gm. tissue for actin. For various degrees of ureteral dilatation, the active stress and contractile protein content showed similar changes. A significant correlation was demonstrated between maximum active stress and contractile protein content. The myosin amount was more closely correlated with maximum active stress, indicating that the content of myosin is a means of predicting contractility of the obstructed, dilated ureter.

Actins↗
PubMed1984

Induction of fructose 1,6-bisphosphatase and glucose 6-phosphatase by dibutyryl cyclic adenosine monophosphate in fetal mouse liver.

In fetal mouse liver fragments maintained in organ culture, the activities of fructose 1,6-bisphosphatase and glucose 6-phosphatase are elevated in the presence of dibutyryl adenosine 3',5'-monophosphate (Bt2-cAMP). Isobutyl-1-methylxanthine at 2.5 mM increased the two enzyme activities. The enzyme activities returned to the normal levels following removal of Bt2-cAMP from the culture medium. Glucagon at concentrations from 10(-11) M to 10(-6) M induced both enzyme activities. The developmental increases in the two gluconeogenic enzymes are supported by cyclic AMP elevated by glucagon. Only at unphysiologically high concentrations did prostaglandin-E1 show weak stimulatory effects. alpha-Adreno-agonists did not stimulate the enzyme activities. Actinomycin D and cycloheximide reduced the enzyme activities stimulated by Bt2-cAMP. Both inhibitors and removal of Bt2-cAMP prevented the incorporation of [3H]leucine into the bisphosphatase. The kinetic properties, subunit-size, and antigenic nature of the bisphosphate showed that the type of enzyme induced by Bt2-cAMP in vitro is identical to the adult liver type. The results are interpreted as indicating that cyclic AMP acts at certain sites in the syntheses of these two gluconeogenic enzymes in the fetal mouse liver.

1-Methyl-3-isobutylxanthine↗
PubMed1984

Effect of glucocorticoids on induction of fructose bisphosphatase and glucose-6-phosphatase in fetal mouse liver.

Glucocorticoids significantly affected the developmental appearance of fructose-1,6-bisphosphatase [EC 3.1.3.11] and glucose-6-phosphatase [EC 3.1.3.9] in fetal mouse liver. In fragments of 15- or 16-day-old fetal livers maintained in organ culture in the absence of serum, induction of the bisphosphatase by dibutyryl cyclic AMP was repressed completely when the tissue was treated with 10(-7)M dexamethasone for 24 h during the second day of culture. The induction of the glucose phosphatase was greatly stimulated after a lag of 1 to 2 days. The glucocorticoid action continued over a period of 2 days even though the steroid had been washed out. The dose response curve of hydrocortisone with the half-maximally effective concentration of roughly 2 X 10(-8)M is in the physiological range. The corticoid action was specific for glucocorticoids, and aldosterone or progesterone was ineffective. When the tissue was cultured for 4 days before addition of dexamethasone, the bisphosphatase induction became insensitive to the steroid. Glucose-6-phosphatase induction, however, remained sensitive, but the long latent period required for the appearance of the hormone action disappeared. These results indicate the involvement of glucocorticoids in the developmental appearance of glucose-6-phosphatase in fetal liver.

Aldosterone↗
PubMed1984

Clinical evaluation of two combination chemotherapies for the treatment of small cell carcinoma of the lung.

The effects of two different combination chemotherapies, i.e. cyclophosphamide (CPM) + vincristine (VCR) + methotrexate (MTX) and ACNU + VCR, with or without radiotherapy, were studied in twenty patients with untreated small cell carcinoma of the lung. Respective response rates were 66.7% for CVM and 50% for AV. Median survival time was 51 weeks for CVM and 27 weeks for AV. There was no statistically significant difference between the survival probability curves of CVM and AV. Concerning toxicity, two hazardous side effects, myelosuppression and interstitial pneumonitis, were observed although the incidences were low. We concluded that both regimens are useful as chemotherapy of small cell carcinoma.

Aged↗