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Biomedical subjects

R Kanayama

Publications and source records attributed to R Kanayama.

At least 37 records · Page 2Linked to original sources
PubMed1991

EOG findings in patients with lesions in cerebellar peduncles.

EOG tests were performed in patients with lesions in either the superior or the middle cerebellar peduncle, because these patients showed cerebellar signs and symptoms and were difficult to distinguish from patients with cerebellar lesions symptomatically. EOGs of these patients showed a predominant decrease of pursuit gains and OKN velocity gains toward the lesioned side, whereas the percent reduction of fixation-suppression of caloric nystagmus decreased predominantly toward the side contralateral to the lesioned side, regardless of whether lesions were located either in the superior or the middle cerebellar peduncle. The present EOGs are best interpreted as a corresponding to a deficit of the neuronal events of the flocculus in the monkey and are solely ascribed to lesions in the cerebellar peduncles, because even well-defined cerebellar lesions on one side showed bilateral impairments of these visually induced eye movements.

Cerebellar Diseases↗
PubMed1991

Quantitative analysis of ocular movements in Parkinson's disease.

In the present study, oculomotor abnormalities were investigated in 24 patients with idiopathic Parkinson's disease. Pursuit gain, slow and fast phase velocity of optokinetic nystagmus (OKN), saccade latency, amplitude and velocity, as well as vestibulo-ocular reflex (VOR) gain were quantitatively analyzed. Twenty-one out of 24 patients showed some abnormalities in their ocular movement. A reduction in pursuit gain, impaired OKN and a significantly increased saccade latency were observed in 11 patients. In 12 patients, hypometric saccade was seen, while a decrease in saccade velocity was observed in 10 patients. All patients registered normal values for VOR gain. Only one patient who had impaired smooth pursuit and decreased saccade velocity before treatment with a dopaminergic drug showed a remarkable improvement in these ocular abnormalities after treatment. These results suggest the possibility of dopaminergic control on these ocular movements.

Aged↗
PubMed1991

Visually induced eye movements in Wallenberg's syndrome.

Eighteen patients with Wallenberg's syndrome were investigated concerning visually induced eye movements. All results were analysed quantitatively using a computer. In 16 out of 18 patients, OKN slow-phase velocities were impaired, in the remaining 2 patients they were normal. Patients who showed impaired OKN were classified into two groups according to directional asymmetry of OKN impairment. In 7 out of the 16 patients, slow-phases toward the lesion side were predominantly impaired in contrast to the slow-phases toward the intact side (group A). In the remaining 9 patients, slow-phases toward the intact side were predominantly impaired (group B). The smooth pursuit showed the same asymmetry as the OKN slow-phase, except, in 4 patients who showed normal smooth pursuit. All patients showed reduced visual suppression of caloric nystagmus during the slow-phase of nystagmus toward the lesion side, except 3 patients who showed normal visual suppression in both directions. CT scan failed to detect either the brainstem or the cerebellar lesions in any cases, but MRI performed on the most recent cases demonstrated the infarctions clearly. These findings suggest that infarctions are localized in the medulla in the patients of group A, but extend to the cerebellum as well as to the medulla in patients of group B.

Adult↗
PubMed1990

Mapping of brainstem lesions by the combined use of tests of visually-induced eye movements.

To determine the diagnostic value of visually-induced eye movements for indicating the lateralization of the lesion, optokinetic nystagmus (OKN), fixation-suppression of caloric nystagmus and pursuit eye movements were investigated in 28 patients who showed discrete unilateral brainstem lesions. In all patients, pursuit gains decreased in parallel with the direction of the impairment of slow-phase OKN velocity with a significant left/right difference. Decreases of gains were predominantly towards the affected side in 22 patients, whereas they were predominantly towards the contralateral side in 2 patients with dorsal tegmental pontine lesions and in 4 out of 8 patients with Wallenberg's syndrome. The relationship of pursuit gains to percentage reduction of fixation-suppression of caloric nystagmus (%FS) showed no correlation. The following four groups were classified. In group A, which was the largest, pursuit gains and %FS decreased predominantly towards the lesioned side. This group consisted of 5 patients with lesions in the midbrain, 6 patients with lesions in the ventral pons and 4 out of 8 patients with Wallenberg's syndrome. The opposite of group A was group D, showing reverse electro-oculographic (EOG) patterns to those in group A in relation to the lesioned side. Group D consisted of 2 patients with lesions in the dorsal pontine tegmentum. This observation, taken together with the decreases of pursuit and OKN gains in relation to the lesioned side, might indicate that lesions of ascending fibres are responsible for pursuit and OKN abnormalities. Group B, consisting of 7 patients with lesions either in the superior or middle cerebellar peduncles, showed decreased pursuit gains predominantly towards the lesioned side and %FS reduced predominantly towards the side contralateral to the lesion. EOGs of these patients were consistent with the results of floccular ablation in the monkey. In group C, these two parameters showed patterns opposite to those in group B in relation to the lesioned side and this group consisted of the other 4 patients with Wallenberg's syndrome. In patients of this group, the inferior cerebellar peduncle might be involved. The combined use of these tests is thus useful for lateralizing the lesion in the brainstem.

Brain Diseases↗
PubMed1986

Computer analysis of optokinetic nystagmus for clinical usefulness.

A computer program was developed for on-line analysis of nystagmus parameters using a microcomputer (SORD M243EX). In this paper, the clinical utilities of microcomputer analysis of optokinetic nystagmus (OKN) were described, and quantitative analysis of each parameter of OKN was performed in 20 normal subjects and 49 patients with central nervous system (CNS) disorders. The average gain was accurately measured and the maximal stimulus velocity during which time the gain was more than 0.8, was termed as the "optokinetic adaptation limit (OAL)," and used as a clinical index for evaluation of OKN abnormalities. All patients in the present study showed a remarkable decrease in OAL. The differences in OAL among these patients at each level of lesion site, however, proved to be statistically insignificant. The relationship between the direction of OKN limitation and the lesion side was investigated. In all patients who had lesions on the thalamus, midbrain, and cerebellum, OKN limitation was observed toward the lesion side. The OKN limitation, however, was seen toward the intact side in 7 of 11 patients with medullary lesions and in 2 of 11 patients with cerebellopontine angle (CPA) tumors. hence, OKN in a useful diagnostic tool for the assessment of infratentorial lesions and computer analysis of OKN may be clinically useful.

Brain Diseases↗
PubMed1986

Electronystagmographic assessment of cerebellar lesions.

Remarkable progress has been achieved in the neurophysiological study of the cerebellum. Based on these neurophysiological data, electronystagmographic (ENG) assessment of cerebellar lesions was made to ascertain to what extent cerebellar lesions could be diagnosed. In 13 patients out of 17 whose lesions were mainly localized on one side through CT, cerebellar lesions could be diagnosed by electronystagmographic findings. In the 1 patient with amyotrophic lateral sclerosis of the remaining 4, asymptomatic cerebellar infarction was detected unexpectedly through CT. In the remaining 3 patients, differential diagnosis from brainstem lesions was difficult to evaluate on the basis of ENG findings. In 13 patients showing cerebellar signs and symptoms, pursuit eye movements, optokinetic nystagmus (OKN), and fixation-suppression of caloric nystagmus were impaired on both sides, suggesting large mass effects upon the bilateral brainstem. However, either rebound nystagmus or opposing positioning nystagmus characteristic of cerebellar lesions was detected in 13 patients (81%). The same was true in patients with bilateral cerebellar lesions. ENG test, however, could not detect any patients who showed neither cerebellar signs nor symptoms. Further investigations are needed to supplement the gap between basic and clinical research.

Cerebellar Diseases↗
PubMed1984

Effect of dietary fat upon ethanol metabolism in rats.

The effect of dietary fat upon ethanol metabolism was studied in rats. Wistar strain male rats were divided into four groups according to diet, namely alcohol-high fat, alcohol-low fat, control-high fat, and control-low fat. After 4 weeks of feeding, blood ethanol levels following an intraperitoneal injection of 0.2 g ethanol/100 g of body weight were measured. The disappearance rate of blood ethanol was faster and the metabolic rate of ethanol was significantly greater in the alcohol-high fat group compared to the alcohol-low fat or non-alcoholic groups. Microsomal enzymes, such as the microsomal ethanol-oxidizing system, aniline hydroxylase, and glucose-6-phosphatase, were significantly higher in the alcohol-high fat group than in the alcohol-low fat or non-alcoholic groups. The ethanol uptake rate of the isolated perfused liver was increased significantly in the alcoholic groups. In the alcoholic rats, the high fat group showed significantly higher uptake than the low fat group. Although the ethanol uptake rate after 4-methylpyrazole treatment was not significantly different among the four groups, its fraction of the total ethanol uptake was increased significantly in the alcohol-high fat group. These results suggest that high fat diets accelerate ethanol metabolism through the microsomal ethanol-oxidizing system.

Animals↗
PubMed1983

Changes of hepatic microtubules and secretory proteins in human alcoholic liver disease.

It has been shown that alcohol consumption disrupts liver microtubules, impairs protein secretion and leads to ballooning of the hepatocytes in rats. Ethanol-induced hepatomegaly was accounted for by an increase of the hepatocytes volume. To study whether these changes occur in human alcoholic liver disease, hepatic tubular protein and export protein content were measured in 29 cases of alcoholic liver disease and were compared with those of 37 cases of non-alcoholic liver disease and 5 cases of non-hepatobiliary disease. Hepatic polymerized tubulin was significantly decreased in alcoholic liver disease compared to non-alcoholic liver disease (p less than 0.01), while free tubulin was increased in alcoholic liver disease. Hepatic transferrin (one of the export proteins) content was significantly higher (p less than 0.01) and serum transferrin level was significantly lower (p less than 0.05) in alcoholic liver disease than in non-alcoholic liver disease. These findings indicated that even in humans, chronic alcohol consumption decreased hepatic microtubules by impairing polymerization of tubular protein and increased hepatic export protein content. This decrease in hepatic microtubules by chronic alcohol consumption may play an important role in the development of human alcoholic liver disease.

Albumins↗
PubMed1982

Effect of cimetidine on the regeneration of the gastric mucosa around a peptic ulcer.

Histological changes in gastric ulcers during the healing process with cimetidine treatment were compared with those seen with conventional treatment. Healing time of the ulcers was clearly shortened, and the regeneration of the marginal mucosa of gastric ulcers was strongly stimulated by cimetidine. Heightening of the marginal mucosa resulted from active regeneration of the mucosal cells and made the endoscopic features mimic those of gastric cancer. These results suggest that it is necessary to differentiate clearly peptic ulcer from gastric cancer before beginning treatment of a gastric ulcer with cimetidine.

Adult↗
PubMed1982

Clinicopathological study of alcoholic fibrosis.

Among 112 patients with alcoholic liver injury, 45 had alcoholic fibrosis. The incidence of alcoholic fibrosis was 40.2% which was the highest among various types of alcoholic liver injury (fatty liver; 3.6%, alcoholic hepatitis; 2.7% and liver cirrhosis; 31.3%). Clinical features of alcoholic fibrosis were milder than those of liver cirrhosis and more severe than those of fatty liver. The mean laboratory values in alcoholic fibrosis were significantly different from those in fatty liver and liver cirrhosis. The laboratory data were well correlated with the presence of pericellular fibrosis and thickening of the terminal hepatic venule, but only partially with hepatic cell necrosis and not with fatty metamorphosis. Two patients with alcoholic fibrosis who developed cirrhosis without any clinical and histological features of hepatitis were observed during 5-yr follow-up. These results indicate that alcoholic fibrosis is the most common type of alcoholic liver injury in Japan and is an independent clinicopathological entity distinct from the classical types of alcoholic liver injury. Pericellular fibrosis and thickening of the terminal hepatic venule which are the main histological features of alcoholic fibrosis may play an important role in its transition to liver cirrhosis.

Aged↗
PubMed1976

Sequential hepatic histologic and histochemical changes produced by diethylnitrosamine in the rhesus monkey.

Six young adult male rhesus monkeys were given diethylnitrosamine ip for 3-5 years. Liver biospies were done monthly. After 6 months, biopsy specimens showed individual hepatocytes and small foci of hepatocytes that were intensely positive for glycogen. During the second and later years, larger foci of such cells developed. In sections stained with hematoxylin and eosin, the glycogen-containing hepatocytes generally appeared unusually clear. Some hepatocytes, however, had eosinophilic or basophilic cytoplasm. Nuclear enlargement and atypic developed, particularly outside the foci. The hepatocytes within most foci were uniform in their histochemical features: glycogen was elevated, glucose-6-phosphatase was decreased, and ATPase activity was present not only along the bile canalicular surface but also along the enire cell membrane. After 3-5 years, neoplastic nodules and hepatocarcinomas developed in 5 of 6 animals. Two nodules and particularly the heptocarcinomas differed from the foci in one of more histochemical parameters. The findings suggested that the glycogen-containing, histochemically altered cells of the foci in one or more histochemical parameters. The findings suggested that the glycogen-containing, histochemically altered cells of the foci may be the first step in the development of neoplasia; further steps toward malignancy appeared to be frequently associated with additional alterations, such as loss of sinusoidal ATPase and re-formation of glucose-6-phosphatase.

Adenosine Triphosphatases↗