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K Obata

Publications and source records attributed to K Obata.

At least 235 records · Page 13Linked to original sources
PubMed1987

Localization of a developmentally regulated neuron-specific protein S54 in dendrites as revealed by immunoelectron microscopy.

We sought to determine the ultrastructural localization of the developmentally regulated neuron-specific protein S54 in the chicken cerebellar cortex and optic tectum. The brains were fixed by perfusion with paraformaldehyde and glutaraldehyde. Frozen sections were immunocytochemically labeled with a monoclonal antibody to S54 protein. The immunoreactivity for S54 protein was localized in dendrites. No immunoreactivity for S54 protein was detected in axons and their presynaptic terminals.

Animals↗
PubMed1987

Four synaptic vesicle-specific proteins: identification by monoclonal antibodies and distribution in the nervous tissue and the adrenal medulla.

Synaptic vesicles from the guinea-pig cerebrum were isolated and administered to mice for the production of monoclonal antibodies (MAb). Four vesicle-associated proteins in the guinea-pig nervous tissue were specifically and differentially recognized by MAbs thus obtained. These proteins had molecular weights of 30,000, 36,000, 38,000 and 65,000 Da and were named SVPs (synaptic vesicle proteins) 30, 36, 38 and 65, respectively. Immunohistochemistry demonstrated that all SVPs were localized in the synaptic regions throughout the central nervous system and in the adrenal medulla. Nerve terminals in skeletal muscle, smooth muscle and sympathetic ganglion contained SVPs 36 and 38. Immunoelectron microscopy of the cerebellar cortex confirmed the localization of SVPs in the synaptic vesicles and the adjacent membranes of the presynaptic nerve terminals. Fractionation of the cerebral tissue and treatment with various agents showed that SVPs were localized in the synaptic vesicles and the synaptic plasma membrane and that SVPs were integrated within the membrane and liberated only after solubilization of the membrane.

Adrenal Medulla↗
PubMed1987

Hemodynamic effects of intravenous diltiazem in patients with acute myocardial infarction.

Experimentally, diltiazem has demonstrated favorable effects on acute myocardial infarction in animals. In this study, we administered diltiazem intravenously to 11 patients with acute myocardial infarction within 24 hours from the onset and examined the hemodynamic changes. Dose was 20 minutes of 0.5 mg/min and 20 minutes of 1.0 mg/min (i.e., total 30 mg). Hemodynamic results were decrease in heart rate, blood pressure (systolic, diastolic), mean arterial pressure, double product (p less than 0.01), and systemic vascular resistance (p less than 0.05). On the other hand, stroke volume index increased (p less than 0.01). There were no significant changes in mean pulmonary capillary wedge pressure, cardiac index, and stroke work index. Serum diltiazem concentrations during intravenous administration in our study were near the steady-state plasma concentrations in which oral multiple-dose administration of diltiazem 60 mg twice or thrice daily resulted in 2 to 3 days. It is concluded that diltiazem can be administered safely to patients with acute myocardial infarction in acute phase and has two favorable hemodynamic effects on acute myocardial infarction. One is decrease of afterload, as evidenced by the decrease in systemic vascular resistance and in mean arterial pressure. Second is the decrease of double product as an index of myocardial oxygen consumption.

Aged↗
PubMed1987

Molecular events associated with neural development.

Analyses of the chick embryo using two-dimensional gel electrophoresis or immunohistochemistry with monoclonal antibodies (MAbs) revealed several molecules which were highly concentrated in the nervous tissue. The properties and developmental changes of these substances were investigated. Three acidic proteins (molecular weights 95, 100 and 110 kDa, respectively) appeared characteristically during the embryonic development. One of them predominated alternatively at each developmental stage. They showed a high degree of homology in the peptide map and complete cross-reactivity with any specific antibodies. Therefore these proteins were considered to make a protein family and were collectively named drebrins. MAbs were produced against the membrane fraction of the neural tubes and somites of three-day chick embryos. Five MAbs stained the migrating neural crest cells and their progeny in histochemistry. In addition, the otic vesicle, including the differentiated labyrinth, and subtypes of human lymphocytes were recognized by these MAbs.

Animals↗
PubMed1987

Phase III trial of the Japanese Urological Cancer Research Group for Adriamycin: cyclophosphamide, adriamycin and cisplatinum versus cyclophosphamide, adriamycin and 5-fluorouracil in patients with advanced transitional cell carcinoma of the urinary bladder.

A non-randomized clinical study on systemic combination chemotherapy was conducted by the Japanese Urological Cancer Research Group for Adriamycin to compare the effectiveness of CAP (cyclophosphamide 200-500 mg/m2, adriamycin 30-50 mg/m2 and cisplatin 30-50 mg/m2) and CAF (cyclophosphamide 200-500 mg/m2, adriamycin 30-50 mg/m2 and 5-fluorouracil 250 mg/m2) in 123 patients (104 evaluable) with advanced and/or metastatic cancer of the urinary bladder. Among 96 patients who were non-randomly selected to receive CAP, 4 achieved complete remission, 12 achieved partial remission, 7 achieved minor response, 30 had stable disease, and 43 had disease progression. The response in the 8 patients who received CAF were: partial remission in 1 and progressive disease in 7. The overall response rate to CAP therapy was 17%, as against 13% for CAF therapy. The median duration of survival with CAP was 29 weeks and with CAF, 22 weeks. The differences between the two groups in duration of survival and response rate were not statistically significant. Complete and/or partial remissions were observed in the lymph nodes, lung and liver in 32%, 24%, and 57% of cases, respectively. There was no objective response in bone metastasis. The main side effects of CAP were anorexia (88%), nausea and/or vomiting (81%), alopecia (65%), leukopenia (72%), anemia (48%), and renal dysfunction (17%). No patients died as a result of toxicity of these combination chemotherapy modalities.

Adult↗
PubMed1987

Comparative analysis of short-term and long-term prophylactic intravesical chemotherapy of superficial bladder cancer. Prospective, randomized, controlled studies of the Japanese Urological Cancer Research Group.

The Japanese Urological Cancer Research Group has conducted three randomized clinical studies on intravesical chemoprophylaxis of superficial bladder cancers. This paper presents a comparative analysis of the first and second of these. The protocol used in the first study was a so-called short-term schedule in which drugs (for group A, ADM 30 mg/30 ml; group B, ADM 20 mg/40 ml; group C, MMC 20 mg/40 ml; and group D, control) were administered twice a week for 4 weeks after transurethral resection (TUR), and in the second study a long-term schedule was used, in which drugs (for group E, ADM 30 mg/30 ml; group F, ADM 20 mg/40 ml; group G, MMC 20 mg/40 ml; and group H, control) were administered twice a week for 1 week, every 2 weeks for 7 weeks, monthly for 8 months, and finally once every 3 months for 1 year. In the first study 575 patients were evaluated and followed up for 5 years. The second study started 28 months later, and 607 patients were evaluated. A generally good prophylactic effect was obtained in the second study when the patients' backgrounds were adjusted in combination with the history and number of the tumors. The second study did not reveal any promoting or inhibitory effect on the progression of the recurrent tumors. There were no significant side effects in either study. The indications and the schedule for prophylactic intravesical chemotherapy should be more carefully studied.

Administration, Intravesical↗
PubMed1987

Projections of two subclasses of vomeronasal nerve fibers to the accessory olfactory bulb in the rabbit.

The organization of the projections of subclasses of vomeronasal nerve fibers to the accessory olfactory bulb was analysed using monoclonal antibodies generated against a homogenate of the rabbit olfactory bulb. Monoclonal antibody R2D5 labels all the somata of vomeronasal receptor cells in the vomeronasal organ as well as all their axons (vomeronasal nerve fibers). Another monoclonal antibody (R4B12), which has been shown to selectively bind and thus identify a subclass of olfactory nerve fibers, also labels a subclass of vomeronasal nerve fibers. The R4B12-positive subclass of vomeronasal nerve fibers project to the glomeruli in the rostrolateral part of the accessory olfactory bulb. The third monoclonal antibody (R5A10) recognizes a complementary subclass of vomeronasal nerve fibers projecting to the glomeruli in the caudomedial part of the accessory bulb. In contrast to the clearly segregated terminations in the accessory bulb, the two subclasses of vomeronasal nerve fibers are intermingled with each other in the vomeronasal nerve bundles. Retrograde labeling of vomeronasal receptor cell somata following injection of horseradish peroxidase within the rostrolateral (R4B12-positive) part of the accessory bulb indicates that vomeronasal receptor cells of this subtype are widely distributed in the vomeronasal sensory epithelium. These results demonstrate the heterogeneity of vomeronasal receptor cells and the specificity of projections arising from subclasses of vomeronasal nerve fibers to the accessory olfactory bulb.

Animals↗
PubMed1987

Monoclonal antibodies to bovine collagenase inhibitor.

Hybridoma antibodies against bovine collagenase inhibitor were produced by fusion of myeloma cells NS-1 (P3-NS1-1) with spleen cells from mice hyperimmunized with collagenase inhibitor purified from the explant medium of bovine dental pulps. Hybridomas positive by an enzyme-linked immunosorbent assay (ELISA) for bovine collagenase inhibitor were cloned by the dilution method. Seventeen hybridomas producing antibodies were isolated, four of which also recognized purified human collagenase inhibitor in the ELISA. Using a monoclonal antibody-Sepharose affinity column, we easily purified both bovine and human collagenase inhibitors to homogeneity. They showed the same mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, corresponding to a molecular mass of 32,000 daltons.

Animals↗
PubMed1987

Telencephalon-specific antigen identified by monoclonal antibody.

Immunohistochemical screening of monoclonal antibodies (mAbs) raised against fractions rich in the dendrodendritic synaptosomes of the rabbit olfactory bulb revealed that one of the mAbs (mAb 271A6) recognized a telencephalon-specific antigen or antigens. Thus, the stain with mAb 271A6 was observed throughout the gray matter of all regions of the neocortex, piriform cortex, hippocampus, striatum, septum, and the amygdaloid nucleus, in addition to the main and accessory olfactory bulbs. The mAb 271A6, however, labeled neither nontelencephalic regions of the central nervous system nor the peripheral nervous system so far examined. Dot-immunobinding assays of homogenates of various brain regions also showed the telencephalon-specific distribution of the antigen designated as 271A6. Antigen 271A6 is developmentally regulated. At birth, the antigen was expressed in a small quantity only in phylogenetically older telencephalic regions such as the olfactory bulb, piriform cortex, striatum, cingulate cortex, and hippocampus. It was hardly detectable in most areas of the neocortex. The densities and areas of 271A6-positive structures increased during the early postnatal period. These results demonstrate a molecular specificity of the most rostral brain segment, the telencephalon. mAb 271A6 may be a good tool for obtaining a better understanding of the molecular basis of the segmental organization or the segment-specific functions of the brain.

Aging↗
PubMed1987

Clinical application of atrial natriuretic polypeptide in patients with congestive heart failure: beneficial effects on left ventricular function.

Synthetic alpha-human atrial natriuretic polypeptide was infused in patients with congestive heart failure (CHF) (New York Heart Association class III or IV) and in those without CHF. The infusion of atrial natriuretic polypeptide (ANP) at a rate of 0.1 microgram/kg/min significantly decreased pulmonary capillary wedge pressure and increased stroke volume index in all of the patients with CHF, whereas it decreased pulmonary capillary wedge pressure but caused no significant change in stroke volume index in the patients without CHF. Concomitant significant reductions in total systemic resistance were observed in both groups of patients. The ANP infusion significantly increased the urine volume, the excretion of sodium, and endogenous creatinine clearance in the patients without CHF. In the patients with CHF, it also showed a tendency to increase all these variables, but the urine volume did not correlate with the reduction in pulmonary capillary wedge pressure. The ANP infusion also decreased plasma aldosterone concentrations in these patients, although no significant difference was observed in the decrement of the plasma aldosterone concentration in the patients with and those without CHF. These findings indicate that the ANP infusion improves left ventricular function in patients with CHF, and suggest that this improvement results mainly from the vasodilating activity of ANP.

Adult↗
PubMed1986

A sandwich immunoassay for human prolyl 4-hydroxylase using monoclonal antibody.

Monoclonal antibody was used in a sandwich enzyme immunoassay and in a radioimmunoassay for human serum immunoreactive prolyl 4-hydroxylase. The enzyme immunoassay utilized a monoclonal antibody as a solid phase and horseradish peroxidase-labeled rabbit antibody (Fab') to human prolyl 4-hydroxylase as a conjugate. Sensitivity was 0.1 ng (0.4 fmol) of enzyme per tube. With a conjugate purified by an enzyme-bound affinity column, sensitivity was increased to 0.01 ng (0.04 fmol) per tube, and linearity was obtained between 0.01 to 30 ng (0.04-125 fmol) per tube. The radioimmunoassay used a 125I-labeled rabbit antibody (IgG) as the conjugate. Sensitivity of this technique was 0.4 ng of enzyme per tube. The enzyme immunoassay gave reproducible quantitation and evidenced a higher enzyme concentration in the serum of patients with liver disorders. Protein immunoblotting showed that the serum immunoreactive prolyl 4-hydroxylase trapped in the sandwich immunoassay was mainly the beta-subunit.

Antibodies, Monoclonal↗
PubMed1986

Identification of a synaptic vesicle-specific 38,000-dalton protein by monoclonal antibodies.

Synaptic vesicles were purified from the guinea pig cerebrum by sucrose density gradient centrifugation, and monoclonal antibodies (MAbs) were produced against this vesicle fraction. Seven MAbs (171B5, 171E8, 174D12, 174H11, 177A2, 177H11 and 178D4) recognized a novel acidic protein of about 38,000 daltons which was specific to synaptic vesicles. In immunofluorescence microscopy, the staining pattern of these MAbs corresponded to the distribution of the synapses in the guinea pig central nervous system. These MAbs appeared to stain all synaptic regions, irrespective of their synaptic function or type of neurotransmitters. MAb 171B5 and 174H11 stained the rat, rabbit and bovine synapses similarly to the guinea pig. Two other MAbs (171E8 and 177H11) stained other mammals weakly but the remaining 3 MAbs reacted only with the guinea pig. In immunoelectron microscopy of both the cerebellar tissue and isolated vesicle fraction, these MAbs selectively labeled the synaptic vesicles but not other structures. Immunoblot analysis was performed on electrophoretically separated proteins in vesicle fraction and brain homogenate. All of 7 MAbs reacted with a band at a molecular weight of about 38,000 from the guinea pig. Isoelectric focussing disclosed that this protein was acidic (pI 4.5-5).

Animals↗
PubMed1986

Immunochemical homology of 3 developmentally regulated brain proteins and their developmental change in neuronal distribution.

Proteins S5, S6, and S54 (mol. wts. 95,000, 100,000, and 110,000 Da) appear characteristically at certain developmental stages in the chick brain (Shirao, T. and Obata, K., J. Neurochem., 44 (1985) 1210-1216). In the present study polyclonal and monoclonal antibodies were developed against electrophoretically purified S5 and S6 proteins. Each polyclonal and monoclonal antibody specifically recognized all 3 proteins, S5, S6, and S54, by immunoblot analysis. The tissue specificities of these proteins were examined by immunoblot analysis with these antibodies. Proteins S5 and S6 were found in the neural tissue and in some non-neural tissues of chick embryo. In the adult chicken, however, they were detected neither in neural nor in non-neural tissues with the exception of the spinal ganglion. Protein S54, on the other hand, was found both in late embryonic and adult neural tissues. It was detected neither in embryonic nor in adult non-neural tissues. Immunohistochemical analysis of adult nervous system showed that S54 protein was present only in neurons. Therefore it is concluded that S54 protein is a neuron-specific protein. Developmental changes of localization of these proteins were then examined by immunohistochemistry. In the developing brain, immunostaining was first observed in newly differentiated neurons, later becoming localized in the neuronal processes. In the adult brain, the immunoreactivity was mainly localized in certain types of synaptic regions, but it was also observed in a small population of neuronal somata.

Animals↗
PubMed1986

Immunological properties of monoclonal antibodies to human and rat prolyl 4-hydroxylase.

Monoclonal antibodies to human (8 clones) and rat (12 clones) prolyl 4-hydroxylase [EC 1.14.11.2] were prepared and characterized as regards subclass, subunit specificity, inhibition and crossreactivity. Among the antibodies to the human enzyme, four clones showed the IgG1 subclass, two IgA, one IgG2b, and one IgM. Four clones reacted with the alpha subunit of the enzyme, while the others reacted with the beta subunit. The enzymatic activity was inhibited by four clones. Five clones crossreacted with the rat enzyme. One clone inhibited the rat enzyme. Among the antibodies to the rat enzyme, seven clones showed the IgG1 subclass, four IgG2a and one IgG2b. Seven clones reacted with the alpha subunit, and four with the beta subunit. One reacted with neither subunit. The enzymatic activity was inhibited by seven clones. Seven clones crossreacted with the human enzyme. Three clones inhibited the human enzyme.

Animals↗
PubMed1986

Induction of coronary artery spasm by acetylcholine in patients with variant angina: possible role of the parasympathetic nervous system in the pathogenesis of coronary artery spasm.

We injected acetylcholine (ACh), the neurotransmitter of the parasympathetic nervous system, into the coronary arteries of 28 patients with variant angina. Injection of 10 to 80 micrograms ACh into the coronary artery responsible for the attack induced spasm together with chest pain and ST segment elevation or depression on the electrocardiogram in 30 of the 32 arteries of the 25 of the 27 patients. The injection of 20 to 100 micrograms ACh into the coronary artery not responsible for the attack in 18 patients resulted in various degrees of constriction in most of them, but no spasm in any of them. After intravenous injection of 1.0 to 1.5 mg atropine sulfate, the injection of ACh into the coronary artery responsible for the attack did not induce spasm or attack in any of the nine coronary arteries injected in eight patients. We conclude that the intracoronary injection of ACh induces coronary spasm and attack in patients with variant angina and that the activity of the parasympathetic nervous system may play a role in the pathogenesis of coronary spasm. We also conclude that the intracoronary injection of ACh is a useful test for provocation of coronary spasm.

Acetylcholine↗