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Biomedical subjects

J Kitamura

Publications and source records attributed to J Kitamura.

At least 37 records · Page 2Linked to original sources
PubMed1996

Cortical potentials preceding voluntary elbow movement in recovered hemiparesis.

Scalp-recorded movement-related cortical potentials (MRCPs) preceding voluntary elbow flexion were studied in two hemiparetic patients 8 months after a stroke. Both cases had unilateral lenticular and internal capsular vascular lesion sparing the cortex. The motor recovery stage of their paretic arm remained in flexion or extension "synergistic" movements of shoulder, elbow, wrist and fingers. The NS' (negative slope) amplitude preceding voluntary unilateral elbow flexion of the intact arm showed a distinct preponderance over the contralateral precentral area, whereas NS' amplitude preceding flexion of the paretic arm was symmetrically maximal at bilateral precentral areas. It is postulated that the unilateral synergistic elbow flexion of the paretic arm is associated with an activation of bilateral brachial areas of the sensorimotor cortex (SI-MIs), whereas the isolated elbow flexion of the intact arm is associated with an activation of mainly the contralateral SI-MI.

Adult↗
PubMed1996

Visual influence on contact pressure of hemiplegic patients through photoelastic sole image.

OBJECTIVES: To assess the visual influence through photoelastic sole image on upright posture in hemiplegic patients. DESIGN: Before-during trial. SETTING: An academically based rehabilitation setting. PATIENTS: Nineteen hemiplegic patients 3 to 8 months after the stroke were designated as severe (n = 5), moderate I (n = 4), moderate II (n = 5), and mild groups (n = 5). The severe, moderate, and mild groups were in Brunnstrom's motor recovery stage II, IV, and V, respectively. Vibration sense in the paretic leg was intact in the moderate II and mild groups, but impaired in the severe and moderate I groups. INTERVENTION: Visual feedback therapy on standing before before and while watching his or her own photoelastic sole image on a television screen (before vs during). MAIN OUTCOME MEASURE: The body-weight-bearing ratio on the paretic sole was analyzed. RESULTS: The body-weight-bearing ratio on the paretic sole increased during visual feedback (before vs during, percentage, severe, 21.8 +/- 11.4 vs 38.7 +/- 13.7, p < .02; moderate I, 30.4 +/- 11.1 vs 39.3 +/- 6.4, not significant; moderate II, 32.8 +/- 10.3 vs 46.8 +/- 7.8, p < .05; mild, 29.7 +/- 7.0 vs 41.8 +/- 7.5, p < .005; mean +/- SD). CONCLUSION: As the only difference between the moderate I and II groups was impaired or intact vibration sense in the paretic limbs, vibration sense along with motor recovery is an important factor to increase body weight loading on the paretic sole in hemiplegic patients.

Adult↗
PubMed1995

Detection of right ventricular infarction by gadolinium DTPA-enhanced magnetic resonance imaging.

We investigated the usefulness of gadolinium-enhanced magnetic resonance (Gd-MR) imaging for diagnosis of right ventricular (RV) infarction in 14 patients with acute inferior infarction. Myocardial perfusion images with thallium 201 and technetium 99m pyrophosphate (dual single-photon emission computed tomography: dual SPECT) and haemodynamic data were obtained on admission. Patients were classified into three groups based on dual SPECT and Gd-MR findings: no accumulation in the right ventricle (negative, Type 1), posterior RV infarction (Type 2) and anterior and posterior RV infarction (Type 3). No patients exhibited the haemodynamic criteria for RV infarction (a mean right atrial pressure above 10 mmHg and a ratio of mean right atrial pressure to pulmonary artery wedge pressure above 0.8). Dual SPECT identified RV infarction in eight patients (three Type 2 and five Type 3, 57% of the total). Gd-MR imaging also identified eight patients (57%) as positive (five Type 2 and three Type 3). Our results showed that Gd-MR imaging was not only useful for diagnosis of RV infarction, but also equal to dual SPECT in sensitivity and specificity, and superior to it as regards acquisition time and assessing the spatial anatomy of heart. In conclusion, Gd-MR imaging is superior to dual SPECT for detection of RV infarction.

Aged↗
PubMed1993

Visual influence on center of contact pressure in advanced Parkinson's disease.

The visual influence on upright posture was studied in seven patients with Parkinson's disease (PD), Yahr stage III to IV, and seven age-matched controls. The position of the center of contact pressure (CCP) between the feet and floor was analyzed by a photoelastic method. When the patients' eyes were closed, the CCP position shifted significantly backward in PD (open, 48.6 +/- 7.6%; closed, 45.0 +/- 4.8%; p < 0.01), whereas in controls, it shifted significantly forward (open, 45.5 +/- 5.8%; closed, 48.9 +/- 2.8%; p < 0.05). PD patients put their body weight less on the more affected foot (open, 49.6 +/- 4.5%; closed, 47.0 +/- 4.8%; p < 0.01) and more on the less affected foot (open, 50.4 +/- 4.5%; closed, 53.0 +/- 4.8%; p < 0.005), when the eyes were closed. Visual information is important in maintaining the upright posture in PD patients.

Aged↗
PubMed1993

Enhanced negative slope of cortical potentials before sequential as compared with simultaneous extensions of two fingers.

Cortical potentials preceding voluntary sequential extension of the right middle finger followed by the index finger were compared with those preceding voluntary simultaneous extension of the two fingers in 7 right-handed subjects who were trained to make the total duration of the EMG discharges approximately the same between the two movements. The negative slope with the sequential movement started earlier and was larger, especially at the vertex and also at the bilateral precentral areas, as compared with the simultaneous movement. There was no difference in the Bereitschaftspotential amplitude between the two movements. It was postulated that a greater and earlier activation of the supplementary motor areas as well as the primary hand sensorimotor areas is associated, both bilaterally, with the execution of the unilateral sequential movement.

Adult↗
PubMed1993

A cortical slow potential is larger before an isolated movement of a single finger than simultaneous movement of two fingers.

Movement-related cortical potentials (MRCPs) preceding voluntary, self-paced, simultaneous extension of the middle and index fingers (two finger movement) were compared with those preceding extension of the index or middle finger alone (single finger movement) of the right hand in 7 right-handed normal subjects. It was meant to double the number of muscles involved in the two finger movement as compared with the single finger movement and to activate only the motor cortex involving the movement of distal joints. The NS' (negative slope) amplitude with the isolated middle finger movement was significantly larger at the precentral area contralateral to the movement as compared with the two finger movement. The NS' amplitude with the index finger movement was also larger than that with the two finger movement at the contralateral precentral area, but the difference was not significant. It is postulated that greater activation of the primary hand sensorimotor area (HSMA) contralateral to the movement might be necessary for the isolated movement of a single finger than for the two finger movement, although a smaller area of HSMA is expected to be activated in the former than in the latter. The NS' may be related to central motor control processes independent of muscle mass activated. As the single finger movement is considered to be more discrete and fine as compared with the simultaneous two finger movement, it is concluded that the HSMA plays an especially important role in discrete and fine finger movement.

Adult↗
PubMed1989

A new family with Joseph disease in Japan. Homovanillic acid, magnetic resonance, and sleep apnea studies.

Four male patients and one female patient of a new family with Joseph disease are reported. Their disease was characterized by autosomal dominant inheritance, bulging eyes, rigidity and spasticity of the lower extremities, dystonia, and bradykinesia. Cerebrospinal fluid homovanillic acid level was markedly reduced. Levodopa improved dystonia. Magnetic resonance imaging revealed mild atrophy of the frontal lobe and the cerebellum and marked atrophy of the lenticular nucleus and the brain stem. Polysomnographic studies revealed non-rapid eye movement stage central type sleep apnea syndrome. This is the first report using magnetic resonance imaging and sleep apnea studies of Joseph disease.

Adult↗
PubMed1988

[Changes in carbohydrate metabolism after major resection of the pancreas, with special reference to the fibrotic pancreas caused by ligation of the pancreatic duct].

Fibrotic pancreas was caused by ligation of the pancreatic ducts in mongrel dogs. Four weeks later, reconstruction of the pancreatic duct and major pancreatic resection were performed. Changes of carbohydrate metabolism and functional and morphological changes of islet cells in the remnant pancreas were investigated. 1) Immediately after resection of more than 84% of the fibrotic pancreas, diabetes developed, and insulin and glucagon secretion decreased, accompanied with marked degeneration of B, A and D cells in the islets. 2) During the early periods after 63 to 84% pancreatectomy, secretion of both insulin and glucagon decreased, and then showed a tendency to recover, but later the secretion gradually decreased again and so-called Sandmeyer's diabetes developed. The size of the islets and the number of B cells decreased, but the rate of A and D cells in the islets increased relatively in the remnant pancreas. 3) After resection of less than 63% of the fibrotic pancreas, secretion of both insulin and glucagon decreased temporarily with subsequent recovery. Diabetes did not develop. There were no marked morphological changes in the islets, nor significant changes in the distribution of B, A and D cells of the islets in the remnant pancreas. Diabetes developed after resection of more than 63% of the fibrotic pancreas 4 weeks after ligation of the pancreatic duct, while it developed after resection of more than 74% of the normal pancreas in dogs. Therefore, with regard to carbohydrate metabolism, resectability of the fibrotic pancreas was about 10% less than that of the normal pancreas in dogs.

Animals↗
PubMed1986

Effects of isosorbide-5-mononitrate on exercise-induced hemodynamic changes in angina pectoris.

Hemodynamic effects of isosorbide-5-mononitrate (ISMN) were studied in 14 patients with effort angina pectoris. Hemodynamic and echocardiographic data were obtained by angina-limited supine multistage bicycle ergometer exercise testing before and 120 minutes after single oral administration of 20 mg of ISMN. Compared with control exercise testing, the ST segment at peak exercise showed less depression after administration of ISMN (p less than 0.001). At rest, systolic and diastolic blood pressure decreased significantly after administration of ISMN (p less than 0.001 and p less than 0.01, respectively). At rest and at peak exercise, pulmonary artery wedge pressure (both p less than 0.001), left atrial volume (both p less than 0.001) and left ventricular end-diastolic volume (both p less than 0.05) decreased, whereas cardiac index, pressure-rate product and systemic vascular resistance did not change significantly after administration of ISMN. Average time to peak plasma ISMN concentration was 90 minutes and average peak plasma concentration was 460 ng/ml with an elimination half-life of 7 hours. These data suggest that the main mechanism of the antianginal action of ISMN is a reduction in left ventricular preload followed by diminution of myocardial oxygen requirements.

Adult↗
PubMed1986

Genotoxic effects of a variety of sterigmatocystin-related compounds in the hepatocyte/DNA-repair test and the Salmonella microsome assay.

The genotoxicity and mutagenicity of 11 fungal metabolites structurally related to sterigmatocystin were examined in the hepatocyte primary culture/DNA-repair test and the Salmonella microsome assay. 10 out of the mycotoxins, i.e. dihydrosterigmatocystin, 5-methoxysterigmatocystin, 5-methoxydihydrosterigmatocystin, 5,6-dimethoxysterigmatocystin, 5,6-dimethoxydihydrosterigmatocystin, sterigmatin, O-methylsterigmatocystin and O-acetylsterigmatocystin showed a positive response for DNA repair, suggesting their carcinogenic potency. 5-Methoxysterigmatocystin, 5,6-dimethoxysterigmatocystin demethylsterigmatocystin and O-acetylsterigmatocystin were mutagenic in TA100 of the bacterial mutagenicity assay with liver S9.

Acetylation↗
PubMed1985

Genotoxicity of fungal metabolites related to aflatoxin B1 biosynthesis.

The genotoxicity of several anthraquinone compounds metabolically related to aflatoxin B1 was examined by means of the hepatocyte primary culture (HPC)/DNA repair test and the Salmonella microsome mutagenesis test, and compared to versicolorins A and B which are potent mutagenic and genotoxic intermediates of the aflatoxin biosynthetic pathway. 6,8-O-Dimethyl-versicolorins A, B and 6-deoxyversicolorin A were found to be strongly mutagenic and genotoxic. Genotoxicity of versicolorin A and 6,8-O-dimethylversicolorin A was stronger than that of versicolorin B and 6,8-O-dimethylversicolorin B, respectively, in the HPC/DNA repair test. Nidurufin and norsolorinic acid, which do not possess a bisfuran ring, exhibited questionable activities for mutagenicity and no genotoxicity. It is suspected that 6,8-O-dimethylversicolorins A, B and 6-deoxyversicolorin A as well as versicolorins A and B are genotoxic carcinogens.

Aflatoxin B1↗