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Biomedical subjects

H Iida

Publications and source records attributed to H Iida.

At least 433 records · Page 24Linked to original sources
PubMed1988

Surgical treatment of achondroplastic dwarfs with paraplegia.

A retrospective study was done to evaluate the results of surgical intervention on the neurological symptoms associated with achondroplastic dwarfs. Between 1971 and 1979, laminectomy was performed on three patients with thoracolumbar spinal canal stenosis associated with achondroplasia. Simultaneous spondylodesis using Harrington instrumentation in conjunction with extensive laminectomy was performed in the most recent case, and excellent results were obtained. We emphasize, therefore, that neurological deficit caused by kyphotic deformity and instability secondary to extensive laminectomy for achondroplasia can be prevented by this procedure, and thus good results can be anticipated.

Achondroplasia↗
PubMed1988

Changes in cardiac performance after dialysis in patients with chronic renal failure.

The effect of hemodialysis on left ventricular performance in 10 uremic patients was studied utilizing echocardiography. Left ventricular function curves constructed by a lower body negative pressure method were compared before and after dialysis. Although hemodialysis caused a decrease in the stroke volume index at rest from 55 +/- 17 to 50 +/- 20 ml/m2, the left ventricular function curve did not show any detectable shift. Thus, it is concluded that a decrease in stroke volume secondary to dialysis is attributable to the reduction in preload, rather than to changes in the contractile state of the left ventricle.

Adult↗
PubMed1988

Oxygen extraction fraction at maximally vasodilated tissue in the ischemic brain estimated from the regional CO2 responsiveness measured by positron emission tomography.

The oxygen extraction fraction (OEF) at maximally vasodilated tissue in patients with chronic cerebrovascular disease was evaluated using positron emission tomography. The vascular responsiveness to changes in PaCO2 was measured by the H2(15)O autoradiographic method. It was correlated with the resting-state OEF, as estimated using the 15O steady-state method. The subjects comprised 15 patients with unilateral or bilateral occlusion and stenosis of the internal carotid artery or middle cerebral artery or moyamoya disease. In hypercapnia, the scattergram between the OEF and the vascular/responsiveness to changes in PaCO2 revealed a significant negative correlation in 11 of 19 studies on these patients, and the OEF at the zero cross point of the regression line with a vascular responsiveness of 0 was 0.53 +/- 0.08 (n = 11). This OEF in the resting state corresponds to exhaustion of the capacity for vasodilation. The vasodilatory capacity is discussed in relation to the lower limit of autoregulation.

Adolescent↗
PubMed1988

Evaluation of regional differences of tracer appearance time in cerebral tissues using [15O] water and dynamic positron emission tomography.

The tracer appearance time relative to the radial artery-sampling site has been evaluated in six brain locations in five human subjects using dynamic positron emission tomography (PET) following the bolus injection of H2(15)O. There was a maximum difference of +/- 2 s from the average in each location. To globally adjust the timing difference between the measured arterial curve and the PET scan, a correction method was developed based on a nonlinear least-squares fitting procedure. This new technique determined the global time delay with an accuracy of +/- 0.5 s. On the other hand, the linear backward extrapolation method resulted in a systematic error of 4 s.

Brain↗
PubMed1988

Serological evaluation of ultrasound examination for chronic schistosomiasis japonica in a previously endemic area--the Chikugo River Basin, Japan.

Ultrasound diagnosis of chronic schistosomiasis japonica was assessed by comparison with the results of serological tests using enzyme-linked immunosorbent assay (ELISA) with egg and adult worm antigen, and the circumoval precipitation test. The subjects were persons resident in the Chikugo River Basin in Kyushu, southwest Japan, where schistosomiasis used to be highly prevalent. Of 93 individuals with a past history of infection, 37 (39.8%) presented the characteristic echo pattern of the disease (network, sieve, mottled or mixed pattern). In the serological tests, the ultrasound (US)-positive subjects showed a significantly higher IgG antibody-positive rate in ELISA (81.1% for egg-ELISA), than the US-negative subjects (37.5% for egg-ELISA). Individuals bearing dead Schistosoma japonicum eggs proven by tissue biopsy showed a similar antibody-positive rate (76.5% for egg-ELISA) to that of the US-positive subjects. Sera of a group which had no schistosomiasis characteristic echo pattern, but had liver fibrosis, hepatomegaly or liver cirrhosis as shown by US, were also highly positive (71.4% for egg-ELISA). The present serological studies thus confirmed the usefulness of ultrasound diagnosis for chronic schistosomiasis japonica. Furthermore, we were able to determine certain indications of liver abnormality currently undefined in the normally utilized US classifications.

Adult↗
PubMed1988

Does cytosolic free calcium concentration in platelets reflect tone and structural changes of resistance vessels?

To investigate tone and vascular changes of resistance vessels as related to cytosolic free calcium concentration [( Ca2+]i) in platelets, we measured forearm vascular resistance and free calcium concentration in platelets from 10 essential hypertensives and 15 normotensives. The [Ca2+]i in platelets was significantly higher in essential hypertensives than in normotensives (184 +/- 43 versus 146 +/- 23 nmol/l, P less than 0.01). The [Ca2+]i levels in platelets were significantly correlated with both systolic (r = 0.50, P less than 0.05) and diastolic blood pressures (r = 0.57, P less than 0.01). Resting vascular resistance and minimal vascular resistance were significantly higher in essential hypertensives than in normotensives (30.6 +/- 12.6 and 2.57 +/- 1.30 versus 16.3 +/- 8.0 and 1.47 +/- 0.63 mmHg/ml per min per 100 ml, P less than 0.05 and P less than 0.01, respectively). Both resting and minimal vascular resistance were significantly correlated with [Ca2+]i in platelets (r = 0.40 and P less than 0.05, r = 0.55 and P less than 0.01, respectively). These results suggest that [Ca2+]i in platelets reflects [Ca2+]i in vascular smooth muscle cells and may be a significant determinant of not only tone but also structural changes of resistance vessels.

Adult↗
PubMed1988

Multistress resistance of Saccharomyces cerevisiae is generated by insertion of retrotransposon Ty into the 5' coding region of the adenylate cyclase gene.

Heat shock-resistant mutants, which were isolated by their ability to withstand lethal heat treatment, were characterized. Resistance was demonstrated to be a consequence of insertion of retrotransposon Ty into either the 5' coding or noncoding region, close to the putative initiation codon of the adenylate cyclase gene CYR1 (or CDC35). These heat shock-resistant mutants contained about threefold lower adenylate cyclase activity than wild-type strains. The mutants were also observed to be resistant to other stresses such as UV light and ethanol. These results demonstrate that multistress resistance, which may confer a survival advantage to yeast cells, can be generated by transposition of a Ty element into CYR1.

Adenylyl Cyclases↗
PubMed1988

Depressed natural killer cell activity in uremia. Evidence for immunosuppressive factor in uremic sera.

We investigated the natural killer (NK) cell activity of peripheral blood mononuclear cells (PBMC) and the suppressive factor of NK cell activity in patients on maintenance hemodialysis (HD). NK cell activity was significantly lower in patients on HD than in healthy controls (20.2 +/- 16.5 vs. 31.0 +/- 13.2%, p less than 0.01). There was no difference in NK cell activity between patients treated with cuprophane and high-permeability membrane. NK cells from patients on HD showed a poor response to interleukin-2, and uremic sera significantly suppressed NK cell activity of normal PBMC. Although urea, creatinine, methylguanidine or guanidinosuccinic acid alone did not suppress the NK cell activity of normal PBMC, the guanidino compound did so significantly. It is suggested that defective NK cell activity in uremic patients explains in part their susceptibility to malignancy and infection. The immunosuppressive effect may be exhibited by synergism or mosaic of uremic toxins.

Adult↗
PubMed1988

Measurement of absolute myocardial blood flow with H215O and dynamic positron-emission tomography. Strategy for quantification in relation to the partial-volume effect.

An in vivo technique was developed for measuring the absolute myocardial blood flow with H215O and dynamic positron-emission tomography. This technique was based on a new model involving the concept of the tissue fraction, which was defined as the fraction of the tissue mass in the volume of the region of interest. The myocardium was imaged dynamically by positron-emission tomography, starting at the time of intravenous bolus injection of H215O. The arterial input function was measured continuously with a beta-ray detector. A separate image after C15O inhalation was also obtained for correction of the H215O radioactivity in the blood. The absolute myocardial blood flow and the tissue fraction were calculated for 15 subjects with a kinetic technique under region-of-interest analysis. These results seem consistent with their coronary angiographic findings. The mean value of the measured absolute myocardial blood flows in normal subjects was 0.95 +/- 0.09 ml/min/g. This technique detected a diffuse decrease of myocardial blood flow in patients with triple-vessel disease.

Angina Pectoris↗
PubMed1988

Monensin turns on microtubule-associated translocation of secretory granules in cultured rat atrial myocytes.

We have studied the effect of monensin on microtubule-associated translocation of atrial secretory granules in 5-7-day-old cultures of atrial myocytes from adult rats. Atrial granules and microtubules were localized by immunofluorescent microscopy of myocytes double-labeled with primary antibodies against atrial natriuretic polypeptide (ANP) and alpha-tubulin. In control myocytes, fluorescence due to atrial granules was predominantly localized to the perinuclear region containing the Golgi complex. After exposure for 30 minutes to monensin (0.5-5.0 microM), myocytes transiently contained conspicuous linear arrays of atrial granules associated with cytoplasmic microtubules. Thereafter, ANP fluorescence accumulated in subsarcolemmal foci at the cell periphery, while perinuclear ANP fluorescence faded. The monensin-induced redistribution of atrial granules was observable in both serum-containing and serum-free media and was unaffected by reducing external Ca2+ to low values, by inhibition of sarcoplasmic reticulum Ca2+ release with ryanodine, or by both. The redistribution was prevented by pretreatment with nocodazole, which fragmented microtubules and scattered Golgi complexes and the associated atrial granules throughout the cytoplasm. Radioimmunoassay showed that monensin seemingly decreased the rate of ANP secretion into the medium from 0.15 to 0.11 fmol/(hr.myocyte). These results suggest that monensin turns on microtubule-associated translocation of atrial granules from the perinuclear areas to the cell periphery by modifying the interaction between microtubules and atrial granules. Monensin also promotes movement of atrial granules along the microtubules but does not accelerate the release of ANP.

Animals↗
PubMed1988

Multiple thoracic disc herniations: case report.

Multiple thoracic disc herniation is rare, and one of the main problems in its treatment has been the lack of accuracy in diagnostic tests. Now, with the advent of computed tomographic scanning with metrizamide in the subarachnoid space, the accuracy has been greatly improved. With computed tomographic scanning, the type and level of the lesion can be demonstrated, even when the myelographic study is unclear. Our report describes the case of a 38-year-old man with multiple thoracic intervertebral disc herniation, who also exhibited symptoms of spinal cord compression. Computed tomographic metrizamide myelography clearly showed anterior compression of the spinal cord due to disc herniation at T5-T6, T6-T7, T7-T8, T8-T9, and T9-T10. Removal of the herniated discs was followed by interbody fusion using autogenous bone grafts, and excellent results were obtained.

Adult↗
PubMed1988

The influence of the hour of the day on the performance of male rats in water multiple T-maze.

The performance of male SD rats in the water multiple T-maze was tested at 2 different times of the day: during the dark phase from 1900 to 2100, the elapsed time between the entry into water and the arrival at ramp was significantly shorter and the number of errors significantly less in comparison with the results of another group of male rats allowed to swim during the light phase from 0700 to 0900. However, only the acceptance of information was retarded, while the keeping of memory remained unaffected.

Animals↗
PubMed1988

Calcium pyrophosphate dihydrate crystal deposition disease in the cervical ligamentum flavum.

The authors describe three cases of cervical radiculomyelopathy caused by calcium pyrophosphate dihydrate crystal deposition disease (CPPDcdd). Radiological investigations revealed nodular calcifications, 5 to 7 mm in diameter, in the cervical ligamentum flavum compressing the spinal cord. Light microscopic, scanning electron microscopic, and x-ray diffraction studies were performed on all three surgical specimens obtained by laminectomy. In two of the cases x-ray microanalysis and transmission electron microscope studies were also performed. This study defined the presence of two patterns of crystal deposition in the ligamentum flavum. One is a nodular deposit, in which hydroxyapatite crystals are seen in the central part of the nodules, with calcium pyrophosphate dihydrate (CPPD) being distributed thinly around them. The other pattern is a linear deposit seen in multiple ligaments and composed of pure CPPD, which causes minimal thickening of the ligaments. A transitional pattern between the two types was also observed. This study revealed details of the nodular deposition of crystals in the ligamentum flavum and demonstrates that CPPDcdd and so-called "calcification of the ligamentum flavum" are the same disease: namely, CPPDcdd. Hydroxyapatite is assumed to have been transformed from CPPD.

Aged↗