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Biomedical subjects

K Kurata

Publications and source records attributed to K Kurata.

At least 145 records · Page 8Linked to original sources
PubMed1988

Differential mechanisms of feeding modulation induced by amino sugars in rats.

The present study examined and compared the effects of N-acetylglucosamine and 1-deoxy-N-acetylglucosamine on feeding behavior with those of glucosamine and 1-deoxyglucosamine. Infusion of 12 mu mole N-acetylglucosamine and 24 mu mole 1-deoxy-N-acetylglucosamine into the rat third cerebroventricle did not affect the feeding behavior. However, oral administration of 1200 mumol N-acetylglucosamine elicited feeding and 2400 mumol 1-deoxy-N-acetylglucosamine markedly suppressed feeding. These effects were abolished by truncal vagotomy. Both glucosamine and 1-deoxyglucosamine affected feeding by intra-third cerebroventricular and oral administration. These findings indicate that N-acetyl amino sugars modulate feeding behavior peripherally through the vagal afferent nerve.

Acetylglucosamine↗
PubMed1987

Serum levels of maprotiline and its adverse effects on depressed patients.

The relationships between the side effects of maprotiline (MPT) and the serum concentration of MPT and desmethylmaprotiline (DMPT) were investigated with 27 blood samplings in 15 depressed inpatients. There were significant correlations between the side effects and serum levels of MPT and DMPT. Mild side effects frequently occurred at levels of more than 130 ng/ml of MPT and 70 ng/ml of DMPT. At more than 220 ng/ml of the MPT levels and 110 ng/ml of DMPT levels, severe side effects occurred. Nearly sigmoidal serum level/side effect response curves occurred with both compounds.

Adult↗
PubMed1987

A comparison of maprotiline and its desmethylated metabolite serum concentrations in outpatients and inpatients.

An investigation was conducted on drug defaulting in 26 depressed patients (11 outpatients and 15 inpatients) treated with maprotiline (MPT), using the interrogation methods and measurements of drug serum levels. All the outpatients visited the clinic regularly and complied with taking the prescripted drugs as directed. The results were as follows: (1) The relationships between the MPT and desmethylmaprotiline (DMPT) serum levels and the daily MPT doses showed highly linear regressions in all the patients, and in the inpatients and outpatients separately. There were significant differences between the regression coefficients obtained in the outpatients and inpatients with respect to MPT (P less than 0.01) and DMPT (P less than 0.001). There was a discrepancy between the results from the patients' reports and measurements of the drug serum levels. This finding indicated noncompliance by the outpatients. (2) Comparing various factors of the outpatients to those of the inpatients, the DMPT/MPT ratio of the former was higher than that of the latter (P less than 0.05). This was also due to the patients' noncompliance, and this ratio, therefore, was considered to be a sensitive marker for checking the compliance of the patients treated with MPT.

Adult↗
PubMed1987

A simultaneous analytical method for catecholamines, indoleamines, and related compounds in 11 rat brain regions.

A simple high-performance liquid chromatographic method that allows the determination of 10 biogenic amines and related compounds for crude brain extracts has been developed. The compounds that can be quantified comprise norepinephrine, epinephrine, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylglycol, dopamine, 5-hydroxyindole-3-acetic acid, homovanillic acid, 3-methoxytyramine, 5-hydroxytryptamine and tryptophan. The detection system involves a three electrode-coulometric determination followed by fluorometric determination. This method is highly selective and sensitive, and in the present study, the usefulness of this methodology was confirmed by applying it to the determination of the levels of these various substances in 11 rat brain regions.

Animals↗
PubMed1987

Radioimmunoassay of atrial natriuretic polypeptide in heat-treated human plasma.

In this simple, sensitive radioimmunoassay (RIA) of atrial natriuretic polypeptide (hANP) in human plasma, nonspecific interference is minimized by deproteinizing the plasma by heat treatment at 85 degrees C for 10 min. We directly measure alpha-hANP in the supernates by RIA, with use of antiserum that recognizes the N-terminal region of alpha-hANP. The minimal detectable value was 0.4 pg per tube. The intra-assay CV was 6.6% (n = 8). The mean concentration of hANP in plasma of 54 healthy volunteers was 41 (SD 29) ng/L. Concentrations of hANP in plasma increased after saline infusion and high salt intake for one week in patients with essential hypertension. High concentrations were also measured in patients with renal failure and congestive heart failure. This method, which requires no extraction or purification with column chromatography, is especially useful for simultaneous measurement of several samples.

Atrial Natriuretic Factor↗
PubMed1987

Role of the glucopyranose ring in the elicitation of feeding.

To relate the structural characteristics of the glucose pyranose ring to feeding elicitation, biochemically and structurally similar glucose analogues were investigated to determine if they could elicit short- or long-term effects on food intake in rats. Testing solutions were infused once into unrestrained and unanesthetised rats through a chronically indwelling cannula in the third ventricle. D-Glucose markedly decreased meal size in doses from 6 to 24 mumol, but it's epimers, D-mannose, D-allose and D-galactose, did not affect food intake. Among the glucose analogues modified at C-2, rats treated with 12 mumol D-glucosamine ate a much larger size of meal than those with 12 mumol halogenglucoses or 24 mumol 2-deoxy-D-glucose, while 2-fluoro-2-deoxy-D-glucose with 2-chloro-2-deoxy-D-glucose induced a more potent feeding than 2-deoxyglucose. Glucosamine also induced hyperglycaemia, but did not affect plasma insulin. Activity of glucose, sensitive neurons in the lateral hypothalamus was increased by electro-osmotic application of 2-deoxyglucose or glucosamine, and the reciprocity was observed on neurons of the ventromedial hypothalamus. One-aminoglucose (beta-D-glucopyranosylamine), which is an aminoglucose analogue modified on C-1, increased meal size and more potently prolonged the duration of the meal compared to 1-deoxyglucose (1,5-anhydroglucitol). Together with the behavioural and structural characteristics of glucose analogues, a hydroxyl group on C-1 or C-2 is involved in feeding elicitation. The magnitude of the effect can be partly explained by the chemical concept of 'inductive effect'.

Animals↗
PubMed1986

D-glucose suppression of eating after intra-third ventricle infusion in rat.

To clarify the hypophagic action of D-glucose, meal size, postprandial intermeal interval and eating rate were analyzed after infusion of glucose into the third cerebroventricle. The effects of glucose structure modification on feeding modulation were examined by comparing the effects of glucose to those of its epimers, D-mannose, D-allose and D-galactose. Glucose, infused in doses of 6 to 24 mumol, dose relatedly reduced meal size, but did not change other meal parameters. The minimum dose of glucose to induce feeding suppression was between three and 6 mumol. The epimers, at doses of 24 mumol, did not affect food intake or body weight. Drinking patterns and ambulatory activity were not changed by glucose infusion. These findings were consistent with neuronal activity observed in the ventromedial hypothalamic nucleus.

Animals↗
PubMed1986

An improved hemagglutination test for study of canine parvovirus.

Optimal conditions for hemagglutination (HA) by canine parvovirus (CPV) strains were investigated using several buffers. Porcine erythrocytes often agglutinated spontaneously in phosphate-buffered salt solution, isotonic saline solution or barbitone-complement-fixation buffer. Results were reproducible when borate-buffered saline (BBS) was used as the diluent for antigen, and "virus adjusting diluent" (VAD), containing 0.15 M NaCl and 0.3 M phosphate was used as the diluent for erythrocytes. Highest HA titers were obtained at pH 6.0 using BBS and VAD. Specific HA with CPV was observed not only at 4 degrees C but at 37 degrees C, and erythrocytes from horse, shrew mouse, hamster, cat, sheep and dog, as well as pig and African green monkey were agglutinated by CPV using the improved method.

Animals↗
PubMed1986

A pharmacokinetic study of clomipramine in regions of the brain.

The pharmacokinetic profiles of clomipramine (CMP) and the serial changes of its concentration in specific brain regions were investigated in rats after an acute treatment with intravenous CMP (10 mg/kg). The CMP concentrations in plasma declined triexponentially and fitted a three-compartment open model. The brain to plasma concentration ratio showed a constant value, 22.2 +/- 4.9, 30 minutes after the injection. Regional brain differences in the CMP distribution and accumulation were also found. Four hours after the injections, the hippocampus was found to have the highest drug concentration, and the concentrations in this region were in the following order; thalamus, striatum, amygdala, cortex greater than pons + medulla oblongata greater than hypothalamus, bulbus olfactorius + septum, mesencephalon greater than cerebellum. Particularly, unique kinetics were observed in the cortex, amygdala and hippocampus.

Animals↗
PubMed1986

Anorexia induced in rat by D-glucosamine deoxidized at C-1.

The effects of D-glucosamine (2-amino-2-deoxy-D-glucose), an endogenous glucose analogue, and 1-deoxy-D-glucosamine on feeding behavior were clarified. Test solutions (24 mumol) were infused into the third cerebroventricle of the rat. Glucosamine induced a feeding episode within 30 min after infusion and then prolonged the ensuing postprandial intermeal interval for the first 4 h of the dark period, while glucose suppressed feeding by decreasing meal size. Ventricular injection of 1-deoxyglucosamine potently suppressed feeding in a dose-related manner by affecting all meal parameters, and oral administration of 2,400 mumol also induced anorexia. Changes in activity of glucose-sensitive neurons in the lateral hypothalamus and glucoreceptor neurons in the ventromedial hypothalamus after electrophoretic application of glucosamine and 1-deoxyglucosamine were compatible with behavior changes. The results indicate that replacement of a hydroxyl group by an amino group at C-2 of the glucose molecule affects feeding behavior and deoxidation of C-1 potently induces anorexia.

Administration, Oral↗
PubMed1986

Radioimmunoassay of metanephrine and normetanephrine for diagnosis of pheochromocytoma.

Sensitive and specific radioimmunoassays of metanephrine and normetanephrine were developed by use of 125I-labeled synephrine and specific metanephrine antibody, and 125I-labeled octopamine and specific normetanephrine antibody. Specific antibody for both metanephrine and normetanephrine was raised in rabbits by immunization with bovine serum albumin conjugated with the corresponding hapten, prepared by the method of Grota and Brown (Endocrinology 1976;98:615). The detection limits of the metanephrine and the normetanephrine radioimmunoassays were 2 and 6 pg/tube, respectively. Mean plasma metanephrine and normetanephrine values for 24 normal subjects were 62 (SD 14) and 100 (SD 40) ng/L, respectively. Mean urinary metanephrine and normetanephrine values for 22 normal subjects were 154 (SD 74) and 217 (SD 109) micrograms/day. For 14 pheochromocytoma patients, plasma metanephrine and normetanephrine values ranged from 29 to 683 and from 28 to 7850 ng/L, and urinary metanephrine and normetanephrine values were 606 to 6630 and 296 to 4800 micrograms/day, respectively. The present methods are simple and suitable for routine tests or for mass screening for pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1986

Premotor cortex neurons in macaques: activity before distal and proximal forelimb movements.

Single unit activity was examined in the premotor cortex of three awake, behaving macaque monkeys. Premotor cortex (PM) neurons were found to be active in association with a movement involving specifically the distal forelimb. Other PM neurons were active in relation to more proximal forelimb movements. The spatial distribution of neurons related to distal movements differed from that of neurons related to proximal forelimb movements, the former being focused at a postarcuate region near the genu of the arcuate sulcus and the latter being shifted more posteromedially. The distal movement was triggered by one of the three sensory signals: visual, auditory, and vibrotactile. Of 190 PM neurons related to the distal forelimb movements, 123 (65%) showed similar premovement activity changes irrespective of the modality of the triggering signal. However, a number of neurons (35%) responded preferentially to one or two of the three signals. The modality-specific activity before movements distinguishes PM from the caudally adjacent primary motor cortex.

Animals↗
PubMed1985

Administration of D-glucosamine into the third cerebroventricle induced feeding accompanied by hyperglycemia in rats.

D-glucosamine, 2-amino-2-deoxy-D-glucose, is known to be an endogenous glucose analogue and to antagonize glucose uptake and metabolism. The present experiments were aimed to clarify effects of glucosamine and related chemical substances on ingestive behavior, as well as its direct effects on hypothalamic neurons. Infusion of 24 mumole glucosamine into the third cerebroventricle induced feeding within 30 min in 5 rats out of 7 tested, accompanied by increased ambulatory activity. No periprandial drinking was observed. Plasma glucose level increased, peaking at 30 min after the injection. Plasma insulin level tended to increase, but not significantly. Electrophoretic application of glucosamine activated glucose-sensitive neurons in the lateral hypothalamus and suppressed glucoreceptors in the ventromedial hypothalamus. These facts, together with other reported results, suggest that glucosamine can modulate physiological feeding and that carbon 2 of the glucose molecule is important in feeding modulation by glucose analogues.

Animals↗
PubMed1985

The effect of cooling of the supplementary motor cortex and adjacent cortical areas.

The medial surface of the rostral part of frontal agranular cortex, largely corresponding to the supplementary motor area, was rapidly and reversibly cooled while a monkey was performing a trained motor task requiring a premovement selection process of determining sensory signals as movement triggering or non-triggering. During cooling, the motor task was poorly performed with grossly altered reaction times and variable amount of force, along with erroneous responses. Neuronal activity in the precentral motor cortex in response to sensory signals was also found to be altered.

Animals↗