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Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 901 records · Page 50Linked to original sources
PubMed1976

Oxidative phosphorylation in brown adipose tissue mitochondria from rats kept under normal environmental conditions.

Based on criteria such as the ADP/O ratio and respiratory control by ADP, the energy-coupling efficiency of brown adipose tissue mitochondria isolated from rats kept under normal environmental conditions for a long time decreased remarkably. The presence of bovine serum albumin, GTP, or ATP plus carnitine in the reaction medium markedly increased the efficiency of oxidative phosphorylation of brown adipose tissue mitochondria. Pre-treatment of brown adipose tissue mitochondria with 2% bovine serum albumin, GTP, or ATP plus carnitine caused a decrease in the amount of free fatty acids bound to the mitochondria from 13.1 to 7.0, 9.0, or 8.2 mug per mg protein, respectively. Removal of the free fatty acids by means of these pre-treatments resulted in restoration of efficient oxidative phosphorylation; there was a correlation between the amount of free fatty acids removed and the degree of recovery in the respiratory control ratio. The elimination of only a fraction of the free fatty acids, as little as 4 mug per mg protein, was sufficient to ensure respiratory control by ADP. It appears that the free fatty acids which lie mainly outside the inner mitochondrial membrane are responsible for the decrease in the efficiency of oxidative phosphorylation in brown adipose tissue mitochondria isolated from rats kept under normal environmental conditions.

Adenosine Diphosphate↗
PubMed1976

The distribution of 14c from [U-14c]glucose in mice using whole-body autoradiography.

Tissue distribution of radioactive carbon from [U-14C]glucose in the mouse in vivo was studied by whole-body autoradiography. The mice were frozen with Dry-Ice-acetone at 0.5, 1, 5 and 30 min, 1 and 24 hr and 1 and 3 weeks after intraperitoneal injection of [U-14C]glucose. Whole-sagittal sections of the frozen mouse, obtained by using a microtome in a cryostat, were dried in a cryostat and autoradiographed. The resulting dry autoradiographs are called untreated autoradiographs in the present work. The sections were then fixed in cold 6% (w/v) HClO4, dried at room temperature and again autoradiographed. Autoradiographs that have undergone this process are referred to as treated autoradiographs. In both untreated and treated autoradiographs, within 1 min following injection of the labeled glucose, the abdominal cavity had the highest autoradiographic density. At 1 hr, density became highest in Harder's, sublingual and duodenal glands, large intestinal mucosa and tongue, and after 3 weeks, no autoradiographic denisty was present.

Adipose Tissue, Brown↗
PubMed1975

Cytarabine and its effect on cerebellum of suckling mouse.

Suckling mice were injected with 30 mg/kg or 50 mg/kg body weight of cytarabine subcutaneously two, three, and four days after birth. Twenty-four hours after the final injection, these mice showed extensive necrosis of undifferentiated cells in the external granular layer of cerebellum. One or two weeks later, a new external granular layer regenerated but it did so only incompletely and regionally. The mice allowed to live longer showed impaired cerebellar function, cerebellar hypoplasia, and other malformations, including heterotopic granule cells in the molecular layer, irregularly arranged Purkinje cells, and scanty cellularity in the internal granular layer.

Aging↗
PubMed1975

Effect of hydrofluoric acid on glucose metabolism of the mouse studied by whole-body autoradiography.

Distribution of radioactive carbon from [U-14C]glucose in the mouse poisoned by hydrofluoric acid has been studied by whole-body autoradiography. Under normal conditions, the highest autoradiographic density was found in the Harder's gland, palatine gland, sublingual gland, large intestinal mucosa, and many regions of the central nervous system 30 minutes after intraperitoneal injection of [U-14C]glucose. On the other hand, after hydrofluoric acid poisoning, it was found that (1) the radioactivity of brain was unchanged throughout all the poisoning; (2) the liver, renal cortex, lung, and blood showed an increase in radioactivity at 180 minutes of poisoning; (3) the abdominal cavity showed a tendency to residual radioactivity with the poisoning; (4) by contrast, Harder's gland, the palatine gland, sublingual gland, and large intestinal mucosa showed a decrease in radioactivity at 180 minutes of poisoning.

Acids↗
PubMed1975

Developmental abnormality of the retina caused by postnatal administration of cytosine arabinoside.

Suckling mice were injectd with 30 or 50 mg cytosine arabinoside/kg body weight 2, 3 and 4 days after birth. Within 6 h after the first injection, a number of pyknotic nuclei were found at the inner portion of the undifferentiated nuclear layer of the retinas. 24 h after the final injection, the retinas of these mice showed the large cavity resulting from necrosis of undifferentiated cells and the rosettes in the nuclear layer. The retinas of 20-day-old treated mice showed conspicuous abnormalities with many rosettes in the outer nuclear layer, heterotopic cell mass in the inner plexiform layer, and irregular arrangement of the ganglion cells. 240 days later, histological abnormalities in the retinas of the treated mice were considerably improved except for rosettes, which were still numerous but changed into arch-like structures.

Animals↗
PubMed1975

Staining method for whole-body autoradiography.

Sagittal whole-body sections of frozen mice were cut on a hydraulicly driven microtome in a cryostat at--15 C by applying cotton or nylon-backed adhesive tape to the mouse before cutting. Section thickness was 20 mu. The sections, still adhering to the tape, were dried in the cryostat (-15C) under atmospheric pressure. After autoradiography, the sections were pressed to a glass slide spread with a mixture of albumin and glycerin. The slide was immersed in xylene at 30 C for 15 min. The tape was then removed from the slide, where the section remained to be stained with hematoxylin-eosin. The section thus obtained enabled the tissue histology to be related to the autoradiogram. This method may also be applied to histochemical studies of substances insoluble in xylene.

Animals↗