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Biomedical subjects

M Nishimura

Publications and source records attributed to M Nishimura.

At least 1,225 records · Page 68Linked to original sources
PubMed1985

Avascular zone in the macula in cicatricial retinopathy of prematurity.

Avascular zones in the maculas of 49 eyes of 33 patients aged 5 to 15 years with cicatricial retinopathy of prematurity were examined by fluorescein angiography. Twenty-three eyes of 18 subjects under 15 years of age who had been born at full term served as controls. The mean diameter of the avascular zones in the patients was 0.22 +/- 0.09 disk diameter, which was smaller than the diameter of 0.32 +/- 0.05 disk diameter in the controls (P less than .001). The patient group was divided into those with avascular zones of 0.2 disk diameter or less, regarded as underdeveloped avascular zones, and those with zones of 0.21 disk diameter or more, considered well-developed avascular zones. In the first group, ocular manifestations in the active stage were statistically more severe than in the second group. Visual acuity was good in most patients in each group.

Adolescent↗
PubMed1985

Autoradiographic studies of cell dynamics in immunogenic granulomas transplanted into the skin of athymic nude mice.

Schistosome egg granulomas in the livers of thymus-intact (nu/+) mice are large and contain eosinophils and mast cells, while those in nude athymic (nu/nu) mice are small and devoid of eosinophils or mast cells. To investigate the cell sources and cell kinetics of hepatic granulomas of nu/+ mice isolated and grafted into the skin of nu/nu mice, biopsies taken after grafting were examined by light and electron microscopy and autoradiography after 3H-thymidine (TdR) injection of either the donor or recipient mice. At 1 week, the grafted granulomas appeared to be amorphous and were surrounded by leukocytes, and the 3H-TdR-labeled donor cells had disappeared. After 2 weeks, repopulation with macrophages began and by 3-5 weeks, the granulomas morphologically resembled hepatic lesions of nu/+ mice. Injection of recipients with 3H-TdR before grafting, showed that labeled macrophages, eosinophils, and mast cells repopulated in granulomas. No granulomas were seen when nu/nu mice were grafted with schistosome eggs alone, and organ culture of nu/+ granulomas before grafting reduced the number of repopulated granulomas. These findings indicate that nu/+ cells in grafted granulomas are replaced by nu/nu cells. Granulomatous reaction of the grafted sites in nu/nu mice is influenced by a substance in nu/+ granulomas, and cells of nunu mice locally acquire a nu/+ type response.

Animals↗
PubMed1985

Distribution of 5-hydroxytryptamine (5HT) in tissue of a mutant mouse deficient in mast cell (W/Wv). Demonstration of the contribution of mast cells to the 5HT content in various organs.

The content of 5-hydroxytryptamine (5HT) in various tissues of mutant mouse (W/Wv) deficient in mast cells and of control mouse (+/+) was determined by high performance liquid chromatography. The depletion of mast cells in the mutant mouse (W/Wv) was expected to cause a decrease in the 5HT content. In the control mice, 5HT was most densely accumulated in the lung (9.66 +/- 5.23 micrograms/g). Large intestine (6.40 +/- 2.61 micrograms/g) and stomach (6.10 +/- 2.14 micrograms/g) followed the lung in the rating of the 5HT content. The 5HT content of W/Wv mice was only 23.4% and 4.1% that of the control in the stomach (p less than 0.01) and the skin (p less than 0.01), respectively. The results were consistent with the expectation. In other organs (small intestine, caecum, large intestine, brain, lung, blood and salivary gland), the difference between the W/Wv and normal mice was not statistically significant. The difference in the 5HT content of the stomach between the two genotypes was 4.67 micrograms/g and was much larger than the 5HT content (0.49 micrograms/g) of normal mouse skin. With regard to the relatively small number of mast cells present in the stomach, the great difference in the 5HT content in the stomach between the two genotypes cannot be explained by the loss of mast cells. Hence, besides mast cells other cells may contribute to the high 5HT content of the stomach.

Animals↗
PubMed1985

CT and histological findings of diffuse lipomatosis with a hemangioendothelioma: a case report.

A 3 1/2-year-old boy with multiple soft tissue tumors and weakness of the right lower extremity is presented. Swelling of the right lower extremity was noted at 3 weeks, and soft masses at the hip at one year and in the inguinal region at 2 1/2 years of age. Right lower extremity weakness was noted about one year and non-progressive. CT scanning demonstrated characteristic subcutaneous lipomatosis with muscle involvement and a pelvic mass with positive enhancement that infiltrated into the spinal canal. Histological examination revealed diffuse lipomatosis involving muscles in the right hip mass and a lipoma with a hemangioendothelioma in the right inguinal mass. Diffuse lipomatosis combined with a lipoma and a hemangioendothelioma suggests a hamartomatous origin.

Buttocks↗
PubMed1985

Developmental changes of neuron-specific enolase in human brain: an immunohistochemical study.

Developmental changes of neurons containing neuron-specific enolase (NSE) in human brain were studied in various areas of the central nervous system by immunohistochemistry with the peroxidase-antiperoxidase (PAP) method. In the brain stem, Purkinje cells, dentate nucleus, globus pallidus and thalamus, the number of NSE-positive neurons increased from an early period in gestation. However, in the pontine nucleus and putamen, it gradually increased along with decreasing cellularity later in gestation and in the infantile period. In the cerebral cortex, NSE-positive neurons developed as late as in the putamen and their cellularity increased earlier in the 5th layer than in the 3rd layer. Developmental changes of NSE-positive neurons parallel phylogenesis. The appearance of NSE-positive neurons can be a marker of neuronal maturation.

Adolescent↗
PubMed1985

NMR imaging and spectroscopy of experimental brain edema.

A canine model of experimental brain edema utilizing the classic cold lesion technique was used to identify the optimal nuclear magnetic resonance (NMR) spin-echo imaging parameters needed to detect cerebral edema with maximum sensitivity. Each animal was studied with four separate spin-echo sequences, utilizing pulse intervals ranging from 0.5 to 2.0 seconds. The echo delays following each pulse interval were 28 and 56 msec. Cerebral edema was best identified with the longest pulse interval (2.0 seconds), and the second echo delay (56 msec). T1 and T2 relaxation values were obtained from in vitro spectroscopy. The relaxation times were prolonged in the edematous white matter; however, absolute T1 and T2 values proved of little use in comparing different animals.

Animals↗
PubMed1985

Biosynthesis and Intracellular Transport of 11S Globulin in Developing Pumpkin Cotyledons.

In vitro studies to explore the biosynthesis of 11S globulin developing cotyledons of pumpkin (Cucurbita sp.) demonstrated that 11S globulin is synthesized on membrane-bound polysomes. M(r) of the translation products (preproglobulin) synthesized by the poly(A)(+)-RNA isolated from developing cotyledons were determined to be 64,000 and 59,000, which are larger than those of the mature globulin subunit (62,000 and 57,000). Preproglobulin is then cotranslationally processed by cleavage of the signal peptide to produce proglobulin. In vivo pulse-chase experiments showed the sequential transformation of the single-chain proglobulin to mature globulin subunit (disulfide-linked doublet polypeptides) indicating posttranslational modification of the proglobulin.Subcellular fractionation of the pulse-chased intact cotyledons showed that the [(35)S]methionine label is detectable in proglobulin in rough endoplasmic reticulum shortly after the pulse label. With time, the labeled proteins move into other cellular fractions: proglobulin in the density = 1.24 grams per cubic centimeter fractions after 30 minutes and mature globulin subunit associated with protein bodies after 1 to 2 hours. The distribution of proglobulin in sucrose density gradients did not correspond with those of catalase (microbody marker) or fumarase (mitochondria marker). An accumulation of proglobulin occurred in the density = 1.24 grams per cubic centimeter fractions, whereas the mature globulin was scarcely detectable in this fraction. In contrast, proglobulin was not detected by immunochemical blotting analysis in the protein bodies prepared under the mild conditions from cotyledon protoplasts. The results suggest that the d = 1.24 grams per cubic centimeter fractions are engaged in the translocation of proglobulin into the protein bodies.

Journal Article↗
PubMed1985

Translocation of photosynthates into vacuoles in spinach leaf protoplasts.

A method was developed for the isolation of vacuoles from the mesophyll protoplasts of spinach leaf, employing the discontinuous Ficoll density gradient centrifugation technique. Isolated vacuole preparations were judged to be free from other organellar fractions based on the assays of marker enzyme activities of individual organelles.Using this isolation method, a time-dependent translocation of (14)C-labeled photosynthates into vacuoles was determined. In contrast to a significant transport of (14)C organic acids such as malate and citrate within 10 to 15 minutes (14)C neutral sugars and amino acids were barely transported into vacuoles during 40 minutes incubation, in spite of the fact that a relatively large amount of these compounds are found in the vacuoles. It was also found that a majority of [(14)C]sucrose remains in the cytosol, apparently not actively moving into the vacuoles. Overall results appear to suggest that vacuoles are not actively engaged in photosynthetic carbon metabolism in spinach leaf protoplasts.

Journal Article↗
PubMed1985

A simple method for estimating intactness of spinach leaf protoplasts by glycolate oxidase assay.

A method was developed for the quantitative analysis of intactness of spinach leaf protoplasts using glycolate oxidase activity as an index. Since glycolate does not penetrate into protoplasts at neutral pH, the increase of O(2) consumption by the addition of glycolate to protoplast suspension was due to the glycolate oxidase activity released from damaged protoplasts. The proportion of damaged protoplasts in the whole preparation was calculated from the ratio of released and total glycolate oxidase activity. Freshly prepared spinach leaf protoplasts were found to be 80 to 90% intact as estimated by the method. The effect of osmolarity on the respiratory activities of spinach leaf protoplasts was also examined by applying the same principle.

Journal Article↗
PubMed1985

Molluscum contagiosum occurring in an epidermal cyst on the eyelid. Light and electron-microscopic studies with literature review.

We hereby report light and electron-microscopic (EM) studies on an unusual case of molluscum contagiosum occurring in an epidermal cyst. It was considered that the pre-existing cyst was inoculated with molluscum contagiosum viruses, which were confirmed electron-microscopically. We also would like to re-emphasize the usefulness of formalin fixed tissue for EM confirmation of viruses.

Child↗
PubMed1985

Involvement of respiratory perception in the resistive load compensation.

Relation of threshold for perception of added inspiratory flow resistance to ventilatory and occlusion pressure response to hypercapnia during external flow-resistive loading was examined in 8 healthy volunteers and 14 patients with chronic obstructive pulmonary disease. Occlusion pressure response to hypercapnia without the load and the threshold for perception were similar between normal subjects and patients. Occlusion pressure at end-tidal PCO2 of 60 mm Hg increased to 134 +/- (SD) 23.4% (p less than 0.01) in normal subjects, but it did not change in patients (113.7 +/- 25.3%). Occlusion pressure response to hypercapnia increased to 155.4 +/- 60% (p less than 0.05) during ventilatory loading in normal subjects but it did not change in patients (105.9 +/- 33%). Inverse correlation between threshold values and changes after loading in occlusion pressure response to hypercapnia was seen in patients as well as in normal subjects. These results indicate in both normal subjects and patients with chronic obstructive pulmonary disease that occlusion pressure response to hypercapnia during the ventilatory loading includes signals from the higher central nervous system and that the lower the threshold, the higher the respiratory drive during the loaded ventilation.

Adult↗
PubMed1985

Carnitine derivatives in hereditary cardiomyopathic animals.

BIO 14.6 Syrian hamsters and diabetic KK mice have been reported to develop hereditary cardiomyopathy spontaneously. In order to investigate the pathophysiological role of carnitine metabolism in hereditary cardiomyopathy, tissue levels of carnitine derivatives and the histology of the heart, liver and skeletal muscles from BIO 14.6 hamsters and KK mice were studied. Free carnitine levels in the heart of the BIO 14.6 hamsters (287.0 +/- 27.0 n mole/g wet tissue) were significantly lower than in the control group (348.8 +/- 83.8, p less than 0.05). Short chain acylcarnitine (197.0 +/- 56.0 n mole/g wet tissue) and total carnitine (667.6 +/- 136.4 n mole/g wet tissue) in the hearts of the BIO 14.6 hamsters were significantly lower than in the control group (short: 425.2 +/- 54.8, total: 1023.6 +/- 81.4, p less than 0.001). There was no significant difference in the levels of various carnitine derivatives of the liver and skeletal muscles from the BIO 14.6 hamsters and control hamsters. On the other hand, carnitine derivatives in KK mice did not change significantly compared with those in the heart, liver and skeletal muscles of the control mice. Histological findings showed that heart muscle degeneration and necrosis were found in both cardiomyopathic animals. Coagulative necrosis was found in both animals, whereas myocytolytic necrosis was found only in the BIO 14.6 hamsters. In KK mice, the right ventricle, especially tissue under the epicardium, was severely affected compared with the left ventricle. In the BIO 14.6 hamsters, however, lesions were scattered over both ventricles with a predilection for the left ventricle.

Animals↗
PubMed1985

Insulin resistance of fat cells from spontaneously diabetic KK mice. Analysis of insulin-sensitive phosphodiesterase.

In an attempt to determine the mechanism of insulin resistance in the presence of obesity, we examined effects of insulin on insulin-sensitive phosphodiesterase (PDE) in spontaneously diabetic KK mice. Isolated fat cells prepared from epididymal adipose tissue were incubated, with or without insulin, for 10 min. In the case of subcellular fractionation, only membrane-bound PDE was activated by insulin, as was noted in the case of rat fat cells. The specific activity was decreased in KK mice compared with control C57BL/6 mice. The dose-response curve, expressed as a percent of the maximal insulin effect, shifted to the right and the increase of ED50 indicated a decreased insulin sensitivity in the KK mice. The maximal insulin effect did not change, either when expressed as a percent of the basal enzyme activity or when expressed on a per cell basis. Specific binding of [125I]-insulin in fat cells increased in KK mice and curvilinear Scatchard plots showed an increase of the high-affinity sites. These data indicate that impairment of PDE activation in fat cells of KK mice relates to postreceptor defects and the uncoupling may result in a decreased sensitivity.

Adipose Tissue↗
PubMed1985

[Measurement of neutrons from an electron accelerator by rem-counter].

In the measurement of neutrons from the medical electron accelerator by a rem counter, two problems disturb accurate measurements. One is the pile-up of signals produced by X-rays during each X-ray burst and the other is the increased counting loss caused by bunched nature of yielded neutrons. The time spectrum of neutrons measured by the rem counter 2202 D (manufactured by Studsvik) rises up to a maximum value by about 20 microseconds and then falls down exponentially with a time constant of about 90 microseconds. On the other hand, that of X-rays is roughly rectangular with several microseconds width. A time discriminating system was prepared to be combined with the rem counter, which was triggered by leading edge of electron beam pulses, rejected pile-up signals due to X-ray bursts, and counted pulses of neutrons in a specified time window. The system discriminated the pile-up enough to measure neutrons at a X-ray dose rate of at least 30 mGy/h. Nonparalyzable counting loss correction was practicable upto about 10 mSv/h for the beam pulse rate of 85 Hz, in which the dead time of the rem counter was estimated as 4 microseconds.

Neutrons↗
PubMed1985

[Regional cerebral blood flow in cerebrovascular disease studied using N-isopropyl-p-(123I) iodoamphetamine].

Twenty-one patients with cerebrovascular disease (5 with hemorrhage, 10 with infarction, 2 with TIA, 4 with motor disturbance of unknown cause) were studied using N-isopropyl-p-(123I)iodoamphetamine (123I-IMP) and single photon emission CT. In 3 of 5 cases with cerebral hemorrhage, perfusion defects were shown in and around the region of hematomas, furthermore, one of the cases with internal capsular hematoma, the perfusion defect extended to the cortical area corresponding to the neurological pathway. In one case with MCA infarction, the perfusion defect was greater and clearer than the low density area on X-ray computed tomography (CT). These results revealed the 123I-IMP study provides physiological information in contrast with X-ray CT which provides anatomical information. In 3 of 9 cases with multiple small deep hemispheric infarctions on X-ray CT, the perfusion to the basal ganglia was suspected to be decreased on 123I-IMP images. However, this visual findings was not definitive and, in fact, the diseased side was not always consistent with the clinical findings. For quantitative analysis, symmetrical regions of interest (ROIs) were constructed both basal ganglia and the ratio of average counts over the ROI to those over the whole slice was calculated. In the small infarction group, the mean +/- S.D. of the values was 0.89 +/- 0.09 in right and 0.89 +/- 0.08 in left. Although the values were not significantly different from those of normal subjects (0.99 +/- 0.02 in right, 0.97 +/- 0.03 in left), they distributed in the range less than normal in 5 of 9 cases. This method was thought to be useful and practical to evaluate the cerebral blood flow in basal ganglia of patients with deep hemispheric infarction.

Amphetamines↗