Biomedical subjects
Publications and source records attributed to K Enomoto.
Explore the source record for details and available documents.
In the abdominal ganglion of Aplysia kurodai, three neurons were identified that responded with inhibition of long duration (ILD) to a single stimulation of the siphon nerve and to bath and iontophoretic application of dopamine. The ILD is a long-lasting (15-60 sec) hyperpolarizing potential, typically associated with a conductance increase but with a reversal potential, typically negative than the potassium equilibrium potential. Exchange of half the external chloride with acetate induced no change in the ILD. The ILD was reduced in amplitude in the presence of 0.1 normal K+ in the external medium and enhanced in two times normal K+ solution. The ILD amplitude, but not conductance, was progressively impaired by cooling and by the metabolic inhibitors ouabain and strophanthidin. These results suggest that the ILD is composed of an increase in K++ conductance and activity of the electrogenic Na-pump. theophylline potentiated the ILD, especially its duration. Furthermore, bath application of dibutyryl cAMP augmented the amplitude of the synaptically elicited ILD and the dopamine responses by 30% over controls without any effect on the change in membrane conductance. Intracellularly injected cAMP also increased the ILD, but 5'-AMP showed no such effect. These data suggest that dopamine acts on the ILD neurons by increasing K+ conductance and the activity of the electrogenic Na-pump and that cAMP might selectively stimulate the pump component of the ILD.
The urinary extracts from patients with aplastic anaemia and from healthy donors were investigated in vivo and in vitro for their ability to stimulate megakaryopoiesis and platelet production. There was a significantly higher concentration of thrombopoiesis stimulating factor (TSF) and megakaryocyte colony stimulating factor (MEG-CSF) in the urine from patients with aplastic anaemia than in that from healthy donors. Neuraminidase treatment did not affect the thrombopoietic activity of TSF, whereas coexisting erythropoietin (EPO) in the extract lost in its activity in vivo. These findings suggest that TSF and/or MEG-CSF seems to be different from EPO and that the urine from aplastic anaemia patients would be a good source of TSF and MEG-CSF for purification and characterization.
Explore the source record for details and available documents.
Since 1973, the balloon catheter test with a Swan-Ganz, Dotter-Lukas or Fogarty catheter has been attempted in our department in cases of atrial septal defect (ASD) and patent ductus arteriosus (PDA) during cardiac catheterization and operation. Accurate informations concerning size, number and location of ASD were obtained during cardiac catheterization studies by using the balloon catheter. The difference between the size of the defect measured at catheterization and at operation was less than 1 mm in diameter. Size of the defect ranged from 13 to 44 mm in diameter (25.7 mm on the average) and bacame larger with patient's age. Measurement of left-to-right shunt ratios before and after the temporary balloon occlusion of the defect was of help in making a preoperative diagnosis of ASD with multiple defects. Size of foramen ovale ranged from 3 to 13 mm in diameter (5.2 mm on the average) and was not related to age. Size of the ductus in cases with PDA was measured during cardiac catheterization by using the balloon catheter. The difference between the size of the ductus measured with the balloon technique at catheterization and with a measuring rule at operation was less than 4 mm in diameter. The difference revealed the extensibility of the ductus. The temporary balloon occlusion of the ductus aided in determining presence of other cardiac anomalies. In cases of isolated PDA, the murmur became inaudible with the occlusion of the ductus. A balloon catheter inflated with radiopaque dye was used for measurements at cardiac catheterization and at operation. Persistent arrhythmias or other adverse effects of this procedure were not observed.
Explore the source record for details and available documents.
Using an immunofluorescent technique, we demonstrated the production of rat embryonic-type hemoglobin in extra-medullary hematopoietic cells, which appeared in the liver of adult Wistar rats fed a diet containing 0.06% 3'-methyl-4=dimethylaminoazobenzene. Specific anti-rat embryonic hemoglobin serum was prepared by immunizing a rabbit with hemoglobin from a 15- or 16-day-old Wistar rat fetus and absorbing with adult rat liver hemogenate and red blood cells. The appearance of hematopoietic foci was observed at both precancerous and cancerous stages during 3'-methyl-4-dimethylaminoazobenzene-induced liver carcinogenesis. At the cancerous stage, almost all these foci were observed in poorly differentiated hepatocellular carcinomas. The hematopoietic cells seen at both stages were stained positively with antiembryonic hemoglobin serum, but red blood cells and other types of cells in the liver did not show this specific fluorescence. These results together with earlier observations on the appearance of fetal characteristics strongly suggest that a fetal environment prevails in the adult rat liver during hepatic carcinogenesis.
A carboxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1) was induced in the liver of rats after repeated administration of phenobarbital. This enzyme migrated most rapidly towards the anode among Triton X-100-solubilized liver esterases by electrophoresis on the cellulose acetate membrane and it was tentatively designated as L-I. L-I increased in the microsomal fraction and was mainly concentrated in the fraction of smooth endoplasmic reticulum that proliferated after phenobarbital treatment. L-I- was separated from other liver esterases and purified about 800-fold. The purified L-I was homogeneous as judged by polyacrylamide gel electrophoresis and exhibited a molecular weight of about 55 000 as determined by gel filtration. L-I split the 1-naphthyl ester of butyric acid faster than esters of acetic, propionic or valeric acids; it therefore seemed to be a butyrylesterase.
The activation of adenylate cyclase in lysed pigeon erythrocytes requires, among several cofactors, a nucleotide which may be ATP, GTP, or many other triphosphates. However, after removal of endogenous nucleotides by gel filtration or by adsorption onto charcoal the requirement can be met only by GTP, or an analog of GTP. The GTP is required during the activation of the cyclase by toxin even if GTP is also included during the subsequent adenylate cyclase assay, conducted without toxin. In the presence of GTP it is possible to assay for the cytosolic protein that is also required for the action of cholera toxin. By gel filtration, its apparent molecular weight is 15,000--20,000.
A microsomal butyrylesterase (L-I) was purified from the livers of male W rats treated with phenobarbital, and an antiserum against this purified L-I was raised in a rabbit. By the Ouchteriony double-diffusion test, a precipitin line was observed between the anti-L-I antiserum and each Triton X-100 extract of livers during development, regeneration after partial hepatectomy, and carcinogenesis and of hyperplastic nodules and hepatomas, all of which revealed L-I in their esterase isoenzyme patterns. These precipitin lines exhibited esterase activity. The fusion of the lines of these tissue extracts and that of the purified L-I indicated the presence of an antigen site common to their esterases. The extracts of adult and fetal livers and also of hepatomas resembling fetal liver in the esterase isoenzyme pattern did not produce a precipitin line with anti-L-I antiserum.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Rabbit cytochrome b5 was incorporated into single-walled phosphatidylcholine liposomes, and the cytochrome b5-liposome complex thus formed was digested with trypsin. Protein chemical characterization indicated that the main products formed were 1) a hydrophilic (heme-containing) fragment of the cytochrome corresponding to the sequence consisting of the masked NH2-terminus through residue 88, 2) a hydrophobic peptide which spans residue 91 to the COOH-terminus (residue 133), and 3) a dipeptide, seryl-lysine, derived from residues 89 and 90. The hydrophobic peptide was obtained in the form of its complex with liposomes. It was concluded that trypsin cleaved rather specifically the peptide bonds between residues 88 and 89 (Arg-Ser) and between residues 90 and 91 (Lys-Leu). Tryptic digestion of free, unbound cytochrome b5 also resulted in the cleavage of the same peptide bonds. These results are not consistent with the proposal of Visser et al. (Visser, L., Robinson, N.C., & Tanford, C. (1975) Biochemistry 14, 1194-1199) that the hydrophilic and hydrophobic domains of cytochrome b5 are connected to each other by a link peptide consisting of some 15 amino acid residues and that this link peptide can be cut out by the action of trypsin. The circular dichroism spectrum of intact cytochrome b5 or its complex with liposomes in the far-ultraviolet region was closely similar to the sum of the spectra of the hydrophilic fragment and the hydrophobic peptide (or its complex with liposomes). This indicates that the tryptic cleavage of the cytochrome molecule does not induce any significant changes in the conformations of the hydrophilic and hydrophobic moieties of the molecule and thus provides further evidence that the three-dimensional structures of the two domains are independent of each other.
A follow-up study on pacemaker function in 15 patients with implanted cardiac pacemaker has been performed by telephone transmission. The transmitting set consisting of electrocardiograph, pacemaker pulse modulator and acoustic coupler was manipulated by the patients themselves. ECG, pacemaker pulse, and pulse rate were simultaneously transmitted through 1 channel to the receiver in our clinic. Of 56 patients with pacemaker, 15 patients were surveyed by telephone transmission. In these patients battery exhaustion was detected in 3, competition in 2, and lead fracture in 1. The fact that surveillance and follow-up of the patients with implanted cardiac pacemaker could be carried out by telephone transmission as well as by clinic visitation tells us that the telephone transmission is a useful method and plays an important role in a pacemaker clinic. Moreover our study established its further usefulness in the patient's preference due to difficulties in travelling to the pacemaker clinic and in reducing patient's anxiety.
Effects of exogenous PG E1 on the level of human plasma norepinephrine (NE), dopamine-beta-hydroxylase (DBH) activity, cAMP, cGMP, free fatty acids (FFA) as well as pulse rate and blood pressure were studied. Significant decreases of blood pressure and increases of pulse rate were observed after 20 min of the infusion of 0.05 microgram/kg/min of PG E1. The level of plasma NE increased by 174% (p less than 0.005) after the infusion. However, the increase of DBH activity was not significant. There was a tendency of increase of plasma level of FFA. These results suggested that the infusion of PG E1 caused an augmented sympathetic nervous activity due to systemic hypotension induced by PG E1.
A quantitative analysis was performed on the extramedullary hematopoietic foci which appeared in the liver during the early stages of hepatocarcinogenesis with 3'-methyl-4-(dimethylamino)azobenzene in rats. The frequency in the appearance of the foci reached a maximum at around 3 weeks of azo-dye feeding. Since the liver in this period has been known to show deviation of various characteristics toward fetal liver, an intimate correlation of the appearance of the foci and fetal character of the liver was suggested. Histologically the hematopoietic foci were always observed in the sinusoidal space of original hepatocytes adjacent to the oval cell proliferating area. Ultrastructurally the cells of the foci were identified as erythroblasts and were found in the space of Disse as seen in the hematopoiesis in fetal liver.
Explore the source record for details and available documents.
Explore the source record for details and available documents.