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Biomedical subjects

H Wada

Publications and source records attributed to H Wada.

At least 1,009 records · Page 56Linked to original sources
PubMed1984

Immunocytochemical localizations of cytosolic and mitochondrial glutamic oxaloacetic transaminase isozymes in rat brain.

The localizations of cytosolic (s-) and mitochondrial (m-) glutamic oxaloacetic transaminase (GOT) were examined by immunocytochemical methods using specific antibodies. Staining of s-GOT-like immunoreactivity was seen in periglomerular cells of the olfactory bulb, and basket, stellate cells of the cerebellum, and second layer cells of the neocortex. On the other hand, m-GOT-like immunoreactivity was found in mitral cells and glomerular regions of the olfactory bulb and deep Golgi cells of the cerebellum. These different distributions of s- and m-GOT isozymes suggest that these isozymes are available as markers of glutamergic or aspartergic neurons.

Animals↗
PubMed1984

Mechanism of inactivation of mammalian L-histidine decarboxylase by (S)-alpha-fluoromethylhistidine.

The mechanism of inactivation by (S)-alpha-fluoromethylhistidine (FMH) of L-histidine decarboxylase (HDC, L-histidine carboxy-lyase, EC 4.1.1.22) purified from whole bodies of fetal rats was studied. FMH inhibited the activities of HDC purified from fetal HDC as well as HDCs from the brain and stomach of adult rats. The activity was not restored by extensive dialysis, indicating that the inhibition was irreversible. The inactivation of HDC was time and concentration dependent and followed pseudo first-order kinetics. L-Histidine, a substrate, protected HDC against inactivation, but D-histidine did not. Apo-HDC was not inactivated by FMH. On labeling of HDC with [3H]FMH, a correlation was found between the extent of incorporation of radioactivity into the enzyme and the degree of inactivation. Two moles of the inhibitor were incorporated into one mole of HDC (108,000 daltons). Experiments with [carboxyl-14C]FMH and [ring 2-14C]FMH showed that decarboxylation was necessary for the inactivation and that one molecule of FMH moiety was incorporated into an HDC monomer during every three decarboxylations of FMH.

Animals↗
PubMed1984

Distribution of the histaminergic neuron system in the central nervous system of rats; a fluorescent immunohistochemical analysis with histidine decarboxylase as a marker.

The distribution of histidine decarboxylase-like immunoreactivity (HDCI) in the rat central nervous system was studied by the indirect immunofluorescence technique. HDCI cell bodies were concentrated in the posterior hypothalamic area, such as in the tuberal magnocellular nucleus, caudal magnocellular nucleus, posterior hypothalamic nucleus and lateral hypothalamus just lateral to the fasciculus mammillothalamicus at the level of the posterior hypothalamic nucleus. Extensive networks of HDCI fibers of various densities were found in many areas of the brain; they were particularly dense in the hypothalamus but were also found in the following areas: rostrally in the cerebral cortex, olfactory nuclei, medial amygdaloid nucleus, n. tractus diagonalis, and bed nucleus of the stria terminalis, and caudally in the central gray matter of the midbrain and pons, auditory system, n. vestibularis medialis, n. originis nervi facialis, n. parabrachialis, n. commissuralis, n. tractus solitarii, and n. raphe dorsalis.

Animals↗
PubMed1984

Stereotactic CT scan applied to stereotactic thalamotomy and biopsy.

A stereotactic method to visualize deep subcortical structures through which the electrode would pass intraoperatively is described in detail. The procedures are: Approximation of the tentative target point in the lateral craniogram according to some craniometric data. Determination of the invading route and its transfer to the patient's scalp. CT scanning by a new generation scanner to distinguish between gray and white matter along the predetermined plane. Intraoperative adjustment of the electrode to the predetermined CT image and error correction. Verification by recording electrical activities in subcortical tissue. This simple method would be of great benefit for the accurate and safe performance of stereotactic thalamotomy and biopsy.

Biopsy↗
PubMed1984

Comparison of histidine decarboxylases from rat stomach and brain with that from whole bodies of rat fetus.

Histidine decarboxylases from the stomach and brain of adult rats were purified 380- and 160-fold, respectively, and their properties compared with those of the enzyme from whole bodies of fetal rats (7600-fold purification). The molecular weights (about 90,000) and the apparent Km values for L-histidine (3 X 10(-4) M) of the three enzymes were similar. The pI value of the fetal enzyme was 5.0, and that of the brain enzyme was 5.4. Histidine decarboxylase of the stomach showed two peaks of activity corresponding to those of the fetal and brain enzymes (pI's of 5.0 and 5.4) on isoelectric focusing. Anti-fetal-histidine decarboxylase antiserum inhibited the stomach and fetal enzymes extensively, but the brain enzyme only slightly. These results indicate that there are at least two types of histidine decarboxylase in rat tissue.

Animals↗
PubMed1984

The differential reaction of histamine and N tau-methylhistamine with Pauly's diazo reagent: application to assay of histamine N-methyltransferase activity.

A simple nonradioisotopic fluorescent method for assay of histamine N-methyltransferase (HMT) activity was developed. After termination of the HMT reaction, the remaining excess substrate, histamine, was degraded by Pauly 's diazo reagent, whereas the product, N tau-methylhistamine (N- MeHA ), was not degraded by the reagent. Then the mixture was applied to high-performance liquid chromatography under conditions in which N- MeHA was not separated from histamine, and N- MeHA was measured fluorometrically by condensation with o-phthalaldehyde. The method would be convenient for measurement of HMT activity during enzyme purification.

Animals↗
PubMed1984

Decreased response of epinephrine and norepinephrine to insulin-induced hypoglycemia in diabetic autonomic neuropathy.

The responses of epinephrine, norepinephrine and other counter-regulatory hormones to insulin-induced hypoglycemia were investigated in 5 diabetics who showed signs of autonomic neuropathy, in 7 age-matched diabetics without autonomic neuropathy and in 7 healthy subjects. The presence of autonomic neuropathy was evaluated by decreased beat-to-beat variation in heat rates during hyperventilation or orthostatic hypotension. Catecholamines were determined by a totally automated plasma catecholamine analyzing system using a two-column system of high performance liquid chromatography. Plasma epinephrine and norepinephrine responses to hypoglycemia in diabetics with autonomic neuropathy were significantly lower than those in diabetics without autonomic neuropathy. Plasma glucagon response in diabetics was apparently attenuated compared to normal controls and there was no significant difference in glucagon response between the two patient groups. Other counter-regulatory hormone responses did not differ among the three groups. The data demonstrate that the responses of plasma epinephrine and norepinephrine to insulin-induced hypoglycemia are impaired in diabetics with autonomic neuropathy.

Adult↗
PubMed1984

Immunohistochemical evidence for the coexistence of histidine decarboxylase-like and glutamate decarboxylase-like immunoreactivities in nerve cells of the magnocellular nucleus of the posterior hypothalamus of rats.

Immunohistochemical staining of alternate consecutive sections revealed numerous histidine decarboxylase (L-histidine carboxy-lyase, EC 4.1.1.22)-like immunoreactive neurons that also contained glutamate decarboxylase (L-glutamate 1-carboxy-lyase, EC 4.1.1.15)-like immunoreactive structures in the tuberal magnocellular nucleus, the caudal magnocellular nucleus, and the postmammillary caudal magnocellular nucleus of the posterior hypothalamus of rats. Furthermore, in immunohistochemical double-staining procedures, almost all neurons in the magnocellular nuclei had both histidine decarboxylase-like and glutamate decarboxylase-like immunoreactivities. These results suggest the coexistence of histamine and gamma-aminobutyric acid in single neurons in these nuclei.

Animals↗
PubMed1984

Mechanism of inactivation of pyridoxal phosphate-linked aspartate transaminase by gostatin.

The inactivation mechanism of pyridoxal phosphate-linked mitochondrial aspartate transaminase (pig heart) by gostatin (5-amino-2-carboxy-4-oxo-1,4,5,6-tetrahydropyridine-3-acetic acid), a novel amino acid produced by Streptomyces sumanensis, was investigated. Gostatin is a time-dependent inhibitor of the enzyme giving an enzyme half-life of 1.8 min at 3.1 microM (25 degrees C). The kinetic properties of the inhibitor suggest that it is a suicide substrate (mechanism-based inhibitor) of the enzyme, and the observed Ki is 59 microM and Kcat is 0.11S-1 at 25 degrees C. Incubation of the enzyme with a stoichiometric amount of the inhibitor (1 mol of inhibitor/1 mol of enzyme monomer) results in complete inactivation. Spectrophotometric titration and gel filtration experiments indicate the binding of 1 mol of gostatin with 1 mol of enzyme monomer. Gostatin serves as an efficient titrant for the enzyme. Liberation of a compound having inhibitory activity against the apo-form enzyme from the enzyme-inhibitor complex under denaturing conditions suggests irreversible modification of the cofactor.

Amino Acids, Dicarboxylic↗
PubMed1984

Histamine metabolism in patients with histidinemia: determination of urinary levels of histamine, N tau-methylhistamine, imidazole acetic acid, and its conjugate(s).

Histamine metabolism in histidinemic patients was studied by measuring the urinary levels of histamine and its metabolites. The urinary excretions of histamine, N tau-methylhistamine, imidazole acetic acid, and its conjugate(s) were higher in patients with histidinemia than in controls, and these levels of excretion were correlated with the plasma histidine level. The urinary histamine levels of patients with eczema-like dermatitis were twice that of those without dermatitis. The urinary excretion of 3-methylhistidine showed a close correlation with the urinary histidine excretion. Thus, it was concluded that histamine metabolism is higher in histidinemic patients than in normal controls.

Amino Acid Metabolism, Inborn Errors↗
PubMed1984

Effect of food intake on urinary excretions of histamine, N tau-methylhistamine, imidazole acetic acid and its conjugate(s) in humans and mice.

The urinary excretions by young healthy men of histamine and its metabolites, N tau-methylhistamine, imidazole acetic acid, and imidazole acetic acid conjugate(s), increased 1-3 h after food intake. The increase was seen even after the intake of konnyaku (mannan) as a protein-deficient food, suggesting that physical stimulation of the gastric mucosa by food is the main cause of histamine release. This suggestion was confirmed by the following findings in patients and mice. In patients with stomach diseases, gastrectomy resulted in decreases in the excretion of histamine and its metabolites in the urine, and patients subjected to intravenous hyperalimentation excreted less histamine and its metabolites in the urine than normal subjects. In mice, a correlation of histamine excretion with food intake was demonstrated experimentally. Namely, mice fed only during the night (21:00-0:00) showed increased excretions of histamine and its metabolites at 23:00-3:00, whereas those fed in the morning (9:00-12:00) showed increased excretions of those compounds at 11:00-15:00. All these results are consistent with the idea that urinary histamine and its metabolites mainly originate from the stomach.

Adult↗
PubMed1984

Surgical treatment of genital Paget's disease in men.

Twenty-one men with genital Paget's disease were treated in our clinic from 1968 to 1983. We report our policy regarding treatment of the clinical disorder, particularly our surgical approach. We also stress that, when considering treatment, the circumstances of the aged patients should take precedence over aggressive treatment of the clinical state of the dermal disease.

Aged↗
PubMed1984

Differential effect of cerebral ischemia on monoamine content of discrete brain regions of the Mongolian gerbil (Meriones unguiculatus).

The effect of bilateral cerebral ischemia on noradrenaline, dopamine, and serotonin concentrations in six brain regions (i.e., the cerebral cortex, striatum, hippocampus, midbrain-diencephalon, cerebellum, and pons-medulla oblongata) was examined in the gerbil stroke model. The relative changes in regional cerebral blood flow after bilateral common carotid occlusion were also assessed using the radioactive microsphere technique. At 1 h after bilateral carotid occlusion, a significant decrease of monoamine concentration was observed in the cerebral cortex, striatum, hippocampus, and midbrain-diencephalon whereas no significant change was detected in the cerebellum and pons-medulla oblongata. The fall in NA content was most prominent in the cerebral cortex and hippocampus and percentage reductions of dopamine and serotonin were greatest in the striatum and cerebral cortex, respectively. These results suggest that the monoamine neurons in various brain regions might have different vulnerabilities to ischemic insult and show no evidence of transtentorial diaschisis.

Animals↗
PubMed1984

Determination of imidazole acetic acid and its conjugate(s) levels in urine, serum and tissues of rats: studies on changes in their levels under various conditions.

A convenient and reproducible method for assay of imidazole acetic acid (ImAA) was developed as a modification of that described previously (Watanabe et al., 1983). ImAA conjugate(s) (ImAA-C), mainly consisting of imidazole acetic acid riboside, could be measured by this method after its hydrolysis to ImAA. The ImAA and ImAA-C levels in various tissues of rats were measured and the effects of various agents on these levels were studied. The renal clearance values of ImAA-C in rats and man were similar to the creatinine clearance values, but those of ImAA were 1/40 of those of ImAA-C, suggesting that the latter is readily excreted in the urine. Consistent with this idea, the urinary excretion of ImAA-C was found to increase much more than that of other histamine metabolites during late pregnancy, when the foetus produces much histamine.

Animals↗
PubMed1984

Responses of catecholamines and other counterregulatory hormones to insulin-induced hypoglycemia in totally pancreatectomized patients.

Responses of glucagon, catecholamines, and other counterregulatory hormones to insulin-induced hypoglycemia were evaluated in five totally pancreatectomized patients and six normal subjects. In pancreatectomized patients, plasma glucagon, probably of gastric origin, did not change significantly during hypoglycemia. The responses of epinephrine and norepinephrine were delayed but adequate compared with those in normal subjects. The responses of cortisol and GH were almost as great as those in normal subjects. However, plasma glucose levels did not recover from hypoglycemia normally in these patients. These results suggest that glucagon responses are essential to recover from hypoglycemia and that neither epinephrine nor norepinephrine plays a crucial role in the recovery from acute insulin-induced hypoglycemia in totally pancreatectomized patients.

Adult↗
PubMed1984

Effect of TEI-4120 (3-benzoyl-N-beta-ethoxyisopropyl-2-methlindole) on carrageenan induced disseminated intravascular coagulation (DIC) in rats.

In order to evaluate TEI-4120 (3-benzoyl-N-beta-ethoxyisopropyl-2-methylindole), as a possible therapheutic compound to disseminated intravascular coagulation (DIC), DIC model in rats was induced by the treatment of lambda-carrageenan according to the method of Sugiyama et al. with minor modification. Two hours after intraperitoneal injection of lambda-carrageenan, plasma fibrinogen decreased and platelet count, prothrombin time, serial thrombin time and plasma TXB2 prolonged or increased. By use of this model, the activities of TEI-4120, new antithrombotic compound, was evaluated compared with three other compounds, aspirin, warfarin and heparin. As a result, TEI-4120 is effective in this model. Combination therapy of TEI-4120 and warfarin is more effective than single administration of TEI-4120. The effect of combination therapy of TEI-4120 and warfarin is consistent with that of heparin. The above result suggests that TEI-4120 seems to be a promising compound to the therapy of DIC.

Animals↗