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Biomedical subjects

H Tohgi

Publications and source records attributed to H Tohgi.

At least 19 recordsLinked to original sources
PubMed1992

A selective reduction of excitatory amino acids in cerebrospinal fluid of patients with Alzheimer type dementia compared with vascular dementia of the Binswanger type.

We determined the concentrations of the putative transmitter amino acids in the cerebrospinal fluid of patients with Alzheimer type dementia (ATD) and vascular dementia of the Binswanger type (VDBT). In ATD, aspartate and glutamate concentrations were significantly and selectively reduced, while in VDBT, concentrations of aspartate, glutamate, gamma-aminobutyric acid (GABA) and many other amino acids were decreased non-selectively. In both ATD and VDBT, we found a tendency for all amino acids to increase with progression of the disease, and this reached statistical significance for some amino acids.

Aged↗
PubMed1992

Concentrations of serotonin and its related substances in the cerebrospinal fluid in patients with Alzheimer type dementia.

We studied concentrations of free and total serotonin (5-hydroxytryptamine, 5-HT) and its related substances in the cerebrospinal fluid from patients with Alzheimer type dementia (ATD) compared with controls. In ATD patients, concentrations of total 5-HT, tryptophan, 5-hydroxytryptophan (5-HTP), melatonin, kynurenine, and 3-hydroxykynurenine decreased significantly. The rate of concentration of tryptophan metabolites to that of tryptophan was significantly reduced for total 5-HT and 3-hydroxykynurenine only. The 5-hydroxyindoleacetic acid (5-HIAA)/5-HT ratio was significantly larger in ATD patients than in controls. The greater reduction in the 3-hydroxykynurenine concentration (81% vs. controls) than in the total 5-HT concentration (51% vs. controls) suggests that the metabolism of tryptophan to 5-HT and 3-hydroxykynurenine is in favor of 5-HT.

Aged↗
PubMed1992

Concentrations of monoamines and their metabolites in the cerebrospinal fluid from patients with senile dementia of the Alzheimer type and vascular dementia of the Binswanger type.

We measured the concentrations of total (conjugated and unconjugated) monoamines (dopamine, DA; norepinephrine, NE) and monoamine metabolites (homovanillic acid, HVA; 3-methoxy-4-hydroxyphenyleneglycol, MHPG; 5-hydroxyindoleacetic acid, 5-HIAA) in the cerebrospinal fluid (CSF), using HPLC-ECD in 11 patients with Alzheimer's disease (AD) or senile dementia of the Alzheimer type (SDAT), 17 patients with vascular dementia of the Binswanger type (VDBT), and 15 controls. In AD/SDAT, there was a significant decrease in the DA concentration and a significant increase in the MHPG concentration. The average NE concentration was not altered, but significantly increased with the progression of intellectual disability. There were no significant changes in HVA and 5-HIAA concentrations. Patients with VDBT showed a significant increase in the DA concentration and a significant decrease in HVA and 5-HIAA concentrations. The DA concentrations increased significantly with the progression of dementia and ventricular enlargement. These results indicate that the noradrenergic and dopaminergic system in particular are altered in AD/SDAT, while the dopaminergic and serotonergic systems are mainly involved in VDBT.

Aged↗
PubMed1992

Effects of low-to-high doses of aspirin on platelet aggregability and metabolites of thromboxane A2 and prostacyclin.

BACKGROUND AND PURPOSE: The purpose of this study was to compare the effects of low-to-high doses of aspirin on platelet aggregability determined by different methods and on the metabolism of thromboxane A2 and prostacyclin. METHODS: We administered increasing doses (40, 320, and 1,280 mg/day) of aspirin to 19 poststroke patients and studied the differences in 1) the changes in platelet aggregability depending on the methods of evaluation and 2) the concentrations of prostaglandin metabolites in the blood and urine. RESULTS: Aggregation of platelet-rich plasma induced by a strong stimulus (10 microM ADP) was significantly reduced after 40 mg/day aspirin (p less than 0.005), and this reduction was similar to that after higher aspirin doses. In contrast, aggregation of platelet-rich plasma induced by weaker stimuli (1 and 5 microM ADP) decreased less significantly after 40 mg/day aspirin compared with that after higher aspirin doses. The serum thromboxane B2 generated after ex vivo incubation was reduced significantly (by 85%) after 40 mg/day aspirin and decreased further after 320 mg/day (by 96%) and 1,280 mg/day (by greater than 99%) of aspirin. The urinary 11-dehydro-thromboxane B2 concentration decreased less significantly after 40 mg/day aspirin (by 42%) compared with that after 320 mg/day (by 78%) and 1,280 mg/day (by 91%) aspirin doses. The urinary concentration of 2,3-dinor-6-keto-prostaglandin F1 alpha did not decrease after 40 mg/day aspirin but decreased significantly after higher doses of aspirin. CONCLUSIONS: These findings suggest that different doses of aspirin may be necessary to prevent thrombogenesis induced by different triggers of different strengths and that 40 mg/day aspirin is able to inhibit a large proportion of maximum thromboxane A2 release provoked acutely, with the prostaglandin I2 synthesis being little affected; however, higher doses of aspirin are required to attain further inhibition.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

[Serial changes of magnetic resonance imagings in acute disseminated encephalomyelitis].

We reported serial changes of MRIs in a case of acute disseminated encephalomyelitis (ADEM). On November 1, 1990, a previously healthy 73-year-old man had a grand mal seizure following myoclonic jerks of the right arm for six days. On admission, he was drowsy and presented with right facial palsy and incomplete tetraparesis. He became coma on the next day of admission. There was moderate leukocytosis. A spinal tap showed a normal opening pressure, 2 white blood cells/mm3, a total protein of 84 mg/dl, glucose of 89 mg/dl. CSF IgG (6.2 mg/dl) and myelin basic protein (6.7 ng/dl) were slightly increased. Serological examinations for virus titer were all negative. A CT scan on the 2nd day showed no abnormal findings, but MRI revealed small high intensity areas in the left thalamus, left prefrontal gyrus and right corona radiata, internal capsule on both the T2-weighted and proton density sequences. An MRI on the 14th day showed high intensity signals in the white matter of the bilateral frontal lobes, left operculum and right corona radiata. In contrast, the left thalamic lesion became smaller and less conspicuous than on the initial scans, but was enhanced with Gd on the T1-weighted sequences. Our findings indicate that MRIs are valuable in detecting pathophysiological changes of ADEM from the acute to chronic phases.

Aged↗
PubMed1991

The significance of 3-O-methyldopa concentrations in the cerebrospinal fluid in the pathogenesis of wearing-off phenomenon in Parkinson's disease.

We determined concentrations of 3-O-methyldopa (3-OMD), L-3,4-dihydroxyphenylalanine (L-dopa), dopamine (DA) and other related substances in the cerebrospinal fluid in patients with Parkinson's disease (PD) 15 h after L-dopa/carbidopa medication, and compared patients with and without the wearing-off phenomenon. Concentrations of 3-OMD significantly increased, and the ratio of DA to 3-OMD was significantly shifted in favor of 3-OMD in patients with the wearing-off compared with patients without the wearing-off. However, concentrations of L-dopa, DA, and homovanillic acid (HVA) were not different between the groups. These results suggest that even if 3-OMD is related to the pathogenesis of the wearing-off, it is not through competition with L-dopa for uptake into the brain, but through other unknown mechanisms within the brain.

Biogenic Monoamines↗
PubMed1991

Concentrations of tyrosine, L-dihydroxyphenylalanine, dopamine, and 3-O-methyldopa in the cerebrospinal fluid of Parkinson's disease.

We determined the concentrations of tyrosine, L-3,4-dihydroxyphenylalanine (DOPA), dopamine (DA), and 3-O-methyldopa (3-OMD) in the cerebrospinal fluid (CSF) of parkinsonian patients and elevated potential interactions between the substances. We found a significant increase in tyrosine, and a significant decrease in DOPA, DA, and 3-OMD. We also found that for a given concentration of DOPA, DA and 3-OMD were proportional. In addition, the ratio of DA to 3-OMD was significantly shifted in favor of DA in parkinsonian patients.

Aged↗
PubMed1991

A significant reduction of putative transmitter amino acids in cerebrospinal fluid of patients with Parkinson's disease and spinocerebellar degeneration.

We evaluated the concentrations of the putative transmitter amino acids in the cerebrospinal fluid, and found a significant reduction of glutamate, aspartate, gamma-aminobutyric acid (GABA), and glycine concentrations in parkinsonian patients. There was no difference in amino acid concentrations between parkinsonian patients receiving L-DOPA and those not receiving L-DOPA. A similar decrease of glutamate and aspartate concentrations was found in patients with spinocerebellar degeneration. Concentrations of asparagine, glycine and taurine were also significantly decreased in patients with late cortical cerebellar atrophy.

Adult↗
PubMed1991

Cerebral perfusion patterns in vascular dementia of Binswanger type compared with senile dementia of Alzheimer type: a SPECT study.

Cerebral perfusion patterns in 18 cases with vascular dementia of Binswanger type (VDBT) (8 moderate and 10 severe cases) were compared with 25 cases with senile dementia of Alzheimer type (SDAT) (16 moderate and 9 severe cases) and 14 controls by single photon emission computed tomography using N-isopropyl-p-123I iodoamphetamine (IMP) as a tracer. The cerebral: cerebellar IMP uptake ratio (%) (CCR) was used as a measured of relative cerebral perfusion. The CCRs were about 85-90% in all areas in controls. Moderate VDBT patients showed a remarkable decrease of CCRs in the basal grey region (thalamus and basal ganglia) (right 79%, left 77%) and in the frontal area (right 79%, left 80%) (P less than 0.01). In severe VDBT patients a significant decrease of the CCR was noted in all regions (P less than 0.01). The decrease of mean CCRs in the hemispheres was significantly correlated with the severity of disease determined by psychometric testing. Patients with SDAT showed a significant decrease of the CCR in the parietal (right 71%, left 74%) and right temporal (78%) areas in the moderate stage (P less than 0.01), and further progression of dementia was associated with low perfusion areas extending to the the frontal areas (78%, P less than 0.01). These differences in the perfusion patterns and their changes with progression of the illnesses may be reflected in characteristic clinical features.

Aged↗
PubMed1991

The risk of cerebral infarction in non-valvular atrial fibrillation: effects of age, hypertension and antihypertensive treatment.

The stroke risk was studied on 600 subjects with nonvalvular atrial fibrillation (NVAF) compared with the general population. The age-matched relative risk of stroke was highest in the 41- to 50-year-old population (12.6) but decreased with age (8.2 for 51-60 years, 3.6 for 61-70 years, and 2.6 for 71-80 years) owing to the increase in stroke incidence with age in the general population. There was no particularly vulnerable period for stroke from NVAF diagnosis until the 15the year. Stroke incidence was greater in hypertensives than in normotensives, but was not different between treated and untreated subjects among hypertensives.

Adult↗
PubMed1991

Platelet volume, aggregation, and adenosine triphosphate release in cerebral thrombosis.

We compared whole blood platelet aggregation, adenosine triphosphate release, platelet count, platelet crit (percentage volume of platelets), and mean platelet volume during the acute, subacute, and chronic periods of cerebral thrombosis in 22 patients with value in 29 controls. During the acute and subacute periods, platelet aggregation, platelet count, platelet crit, and mean platelet volume were significantly less in the patients than in the controls (p less than 0.05-0.01) while the adenosine triphosphate release rate per volume of platelets was significantly greater (p less than 0.05). During the acute period, infarct size showed a significant positive correlation with platelet aggregation (r = 0.59, p less than 0.01) and adenosine triphosphate release rate (r = 0.70, p less than 0.001) but a negative correlation with platelet count (r = -0.44, p less than 0.05). Our results suggest that platelet aggregation is reduced during the acute period due to the consumption of platelets during thrombogenesis but that the remaining individual platelets are hyperactive. Platelet consumption during the acute period increases with infarct size. During the chronic period, platelet crit and mean platelet volume were significantly less in the patients than in the controls (p less than 0.01) while the adenosine triphosphate release rate was significantly greater (p less than 0.01), suggesting sustained platelet consumption and chronically enhanced secretion of individual platelets.

Adenosine Triphosphate↗
PubMed1991

Twenty-four-hour variation of blood pressure in vascular dementia of the Binswanger type.

Using a noninvasive portable blood pressure recorder, we compared 24-hour variations of blood pressure among 1) 35 patients with Binswanger-type dementia, 2) 43 with lacunar-type dementia, 3) 26 with a single lacunar stroke, and 4) 30 controls. Each group was divided into antihypertensive-treated and -untreated subgroups. Among the untreated subgroups, patients with Binswanger-type dementia had significantly greater 24-hour mean systolic blood pressures, 24-hour systolic blood pressure standard deviations, and maximal systolic blood pressure variations than the controls (p less than 0.05). Among the treated patients, blood pressure variability increased similarly in all subgroups with cerebrovascular lesions compared with the controls (p less than 0.05). The nocturnal blood pressure decreases seen in the controls were absent among both untreated and treated patients with Binswanger- or lacunar-type dementia (p less than 0.05). Our results suggest the importance of hypertension, short-term variations in blood pressure, and a sustained nighttime elevation of blood pressure for the pathogenesis of both Binswanger-type and lacunar-type dementia in patients receiving antihypertensive medication.

Aged↗
PubMed1991

Age-related changes in rates of basal secretion of immunoreactive vasoactive intestinal polypeptide and dopamine into pituitary stalk blood from the hypothalamus in anesthetized male rats.

Age-related changes in prolactin (PRL) in systemic blood plasma, and in secretions of hypothalamic vasoactive intestinal polypeptide (VIP), an important candidate for PRL-releasing factor, and dopamine, a PRL-inhibiting factor, into the pituitary stalk blood were investigated. The experiments were performed on male urethane-chloralose-anesthetized Wistar rats of three different ages, i.e., (1) adult rats 5-8 months old, (2) middle-aged rats 12-15 months old, and (3) aged rats 24-26 months old. The concentration of immunoreactive PRL (iPRL) in systemic blood plasma of the aged rats was significantly higher than that of the adult rats (p less than 0.01). The secretion rate of hypothalamic immunoreactive VIP (iVIP) into the pituitary stalk blood was unchanged during aging, while that of dopamine was markedly increased in the aged rats in comparison with the value in both adult and middle-aged rats (p less than 0.01). These results indicate that the basal secretion of hypothalamic VIP is well maintained, while that of hypothalamic dopamine is augmented in aged rats with hyperprolactinemia. It can be assumed that the increase in the pituitary PRL secretion is a primary event during aging in rats, and that a high circulating level of PRL may facilitate the hypothalamic dopamine secretion through the activation of a negative feedback system of the hormone.

Aging↗
PubMed1991

[Effect of aging on in vivo binding of 11C-N-methylspiperone in living human frontal cortex].

Reduced in vivo binding of 11C-N-methylspiperone (NMSP) with age in the living human frontal cortex was demonstrated, with positron emission tomography (PET). Eleven normal male volunteers (22 to 72 years old) were assessed. The uptake of 11C-NMSP in the frontal cortex peaked 7-15 min after intravenous injection, and then gradually decreased until the end of this study. On the other hand in the cerebellum, the uptake of 11C-NMSP peaked 10 min and rapidly declined. We analyzed the data using a three compartment model and determined rate constants k3 and k4. And the binding potential of receptors was estimated as the ratio of k3 (association rate constant) to k4 (dissociation rate constant) value. The k3 and k4 values were calculated from nonlinear regression, given by the set of parameter values that minimized the deviation between the measured kinetics and model prediction. As an input function, we used the radioactivity in the cerebellum. A significant reduction in BP with age was observed. Though both k3 and k4 values were decreased with age, this decrease of BP was found to be mainly due to the reduced k3 values. These results indicated that numbers of binding sites (Bmax) of serotonin S2 receptors in frontal cortex might be decreased with age.

Adult↗
PubMed1990

Effect of a synthetic norepinephrine precursor, L-threo-3,4- dihydroxyphenylserine on the total norepinephrine concentration in the cerebrospinal fluid of parkinsonian patients.

We studied the effect of a synthetic norepinephrine precursor, L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on the total (conjugated and unconjugated) norepinephrine concentrations in the cerebrospinal fluid (CSF) of 6 parkinsonian patients with freezing phenomenon. The total norepinephrine concentrations in the CSF increased from 5- to 75-fold after treatment with L-threo-DOPS. The degree of increase in the norepinephrine (NE) concentrations was closely correlated to the dosage of L-threo-DOPS. The freezing phenomenon improved in 3 out of 6 patients.

Carbidopa↗