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Biomedical subjects

T Kumamoto

Publications and source records attributed to T Kumamoto.

At least 181 records · Page 10Linked to original sources
PubMed1981

Decreased uptake of GABA by dorsal ganglia in methylmercury-treated rats.

The uptake of 14C-GABA and 14C-choline by cerebral cortex slices did not show any change in rats which showed neurological signs 7 days after the last 7 methylmercury injections (10 mg/kg/day). However, 14C-GABA uptake by dorsal ganglia greatly decreased, although 14C-choline uptake did not decrease in dorsal ganglia. 14C-GABA uptake by cerebellum also was somewhat decreased. The degree of inhibition of 14C-GABA uptake by dorsal ganglia increased each day after the commencement of methylmercury injection. The decrease of 3H-GABA uptake by dorsal ganglia of methylmercury-injected rats was confirmed by autoradiography. Autoradiographic and inhibitor studies showed labelled GABA accumulated in the satellite glial cells. In vitro addition of methylmercury (10(-4)-10(-5) M) equally inhibited the uptake of GABA and choline by brain and dorsal ganglia slices. These studies may reveal a possible mechanism of methylmercury neuropathy.

Animals↗
PubMed1980

Rimmed vacuoles.

Rimmed vacuoles (Dubowitz and Brooke 1973) have been found in 12 cases with various neuromuscular diseases and are considered to be autophagic in nature. They consisted of multilaminated membranous structures accompanied by glycogen granules, dense bodies, and amorphous, granular, and fibrillar material. The contents of the vacuoles were regarded as having partially dissolved out of the vacuoles in cryostat sections but some were plastered along the walls of the vacuoles and were depicted by the staining procedures for light microscopy. The "lined vacuoles" described by Carpenter et al. (1978) in inclusion body myositis closely agree with the rimmed vacuoles in respect of histochemical and ultrastructural features.

Adolescent↗
PubMed1979

Fine structural correlations between the muscle pathology of amyotrophic lateral sclerosis (ALS) patients and experimental Ca-Mg deficient rats.

Nonspecific myofibrillar changes such as streaming of the Z-line, formation of rod-like structures, satellitosis, proliferation of sarcolemmal nuclei and papillary projection of the sarcolemma were recognized as a disorganization of the muscle itself. In addition, fine structural pathology in ALS specimens showed characteristically a pig-tail formation - 'Zopfformation' - which has been considered to have a neurogenic origin.

Amyotrophic Lateral Sclerosis↗
PubMed1977

Experimental protein malnutrition in primates: electronmicroscopic observations on the cerebellum of healthy and malnourished squirrel monkeys (Saimiri sciureus).

Eight young adult squirrel monkeys were maintained on a protein deficient (2% calories from proteins) diet for a period of 15 weeks during which the animals lost wieght steadily and developed varying degrees of sensory and motor impairments as evidenced by lack of interest in the surrounding environment and changes in posture and gait. An additional eight animals were maintained on a high protein diet (25% calories from proteins) to serve as controls. Two animals each from the experimental and control groups were sacrificed at 9, 11, 13 and 15 weeks of special feeding schedule. The Purkinje cells of the cerebellum of malnourished animals showed significant changes in the ribosomes, endoplasmic reticulum and Golgi zone indicating greatly disturbed protein metabolism. The granule cells, especially of the pale variety show prominent watery swellings with scant cell organelles. The most prominent change appeared in various types of neurons related to the multiplication of various types of lysosomes, multivesicular lamellar bodies and the lipofuscin pigment bodies. In the animals sacrificed at different intervals, the relatively more malnourished animals showed significantly larger number of lipofuscin pigment in the various types of neurons of the cerebellar cortex. The dendritic changes included honey-comb formation in the lumen. The astrocyte glial fibers were greatly increased. The pericytes of the blood vessels showed irregular outlines and were greatly enlarged with numerous osmiophilic bodies (presumably lipofuscin) in the experimental animals as compared to the controls.

Animals↗
PubMed1976

On the histochemistry of neuronal and glial TPPase.

Thiamine pyrophosphatase (TPPase) activity in the neuronal Golgi apparatus and in glia cells was investigated using different tissue preparation techniques such as fresh frozen and fixed frozen sections, the effect of ATP as an activator and the fine structural localization of the enzyme activity in glia cell processes and the glio-vascular contact point was observed under the electron microscope. TPPase was demonstrated in the glia cell using only a fixed frozen tissue preparation, activated by ATP with the concentration as low as 0.1 mM. On the contrary, enzyme activity was detected in the Golgi apparatus of the neuron regardless of tissue preparation, fresh or fixed frozen, or by the addition of ATP to the incubation medium. The identity of the glia cell type showing a positive reaction for TPPase is thought to be part astrocyte and part microglia. The fine structural observation of TPPase localization at the glia cell process ending, particularly at the glio-vascular and glio-fibral (medullated fiber) contact point suggests a functional role of this enzyme for transport of metabolites through glia cell processes to neurons and/or the blood capillary, and also may play a role in regulation of co-carboxylase.

Adenosine Triphosphate↗
PubMedDate not supplied

Fluorescence polarization study of a salt bridge between a single chain Fv and its antigen ribonuclease A.

The interaction between a single chain Fv (sFv) of the monoclonal antibody 3A21 and its antigen, bovine pancreatic ribonuclease A (RNase A), was studied by site-directed mutagenesis of the hypervariable regions and fluorescence polarization analysis. The affinity constants of wild-type sFv and a mutant sFv D31A (Asp31 of heavy chain was replaced by Ala) for RNase A were found to be 2.7 x 10(7) and 4.7 x 10(6) M(-1) in PBS at pH 7.2 and 37 degrees C, respectively. Whereas the affinity constant of D31A is not affected by NaCl concentration, that of wild-type sFv is almost the same as that of D31A in the presence of more than 1 M NaCl. These results demonstrate that Asp31 of the heavy chain interacts electrostatically with a positively charged amino acid residue of RNase A.

Animals↗