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Biomedical subjects

M Adachi

Publications and source records attributed to M Adachi.

At least 739 records · Page 41Linked to original sources
PubMed1981

Long-term intracellular retention of hexosaminidase A by Tay-Sachs disease brain and lung cells in vitro.

Enzyme-replacement treatment for metabolic storage disorders has been widely studied using model cell culture systems. This study determines the long-term fate of human hexosaminidase A supplied to Tay-Sachs disease brain and lung cells. Hex A retention studies showed that the incorporated Hex A is retained in undiminished quantity by TSD lung cells maintained in stationary culture for 14 days. Tay-Sachs disease brain cells similarly followed for 28 days in stationary culture showed an initial reduction in Hex A for 3 days, after which the Hex A level stabilized and remained relatively constant for the next 25 days. Hexosaminidase B isoenzyme was found to accumulate in both cell lines during extended cultivation, despite the observation that significant amounts were excreted into the extracellular environment. The demonstration of long-term intracellular retention of exogenously supplied therapeutic enzyme by the target cells offers additional evidence for the feasibility of an enzyme-replacement approach for study and treatment of lysosomal storage disorders.

Brain↗
PubMed1981

Porosity--strength relationship in a Cu-rich spherical alloy amalgam.

Porosity and strength of spherical Cu-rich alloy amalgams were analyzed in the under-graduate materials laboratory. The minimum value for porosity was obtained for 46% initial Hg content, whereas the maximum strengths were obtained for 42% initial Hg. This result did not coincide with the data previously obtained for the conventional spherical alloy amalgam, in which the maximum strength and the minimum porosity were strictly associated with the optimum initial Hg content. Although no critical value for porosity could be definitely demonstrated by this effort, this result may be an indirect indication for 4.5 vol% porosity as the critical value.

Copper↗
PubMed1981

[Retention of three different luting cements (author's transl)].

Employing zinc phosphate, polycarboxylate and glass ionomer cements, effect of cement layer thickness on retention of crowns at their axial wall was investigated. Stainless steel preparations and occlusally perforated crowns having taper angles of 2.9 and 5.7 degrees were cemented, regulating the thickness at the axial wall from 5 to 60 mu. These dies were stored in a 100% relative humidity atmosphere at room temperature or in distilled water. After 48 hr, retention was measured, applying the load vertically to occlusal preparation surface through a plunger (Fig. 1). Due to the inclusion of unreacted powder particles in the set structure of all three cements, evidence of a critical value was always shown in the cement thickness-retention relationship (Figs. 2, 3 and 4). When the cement thickness was reduced below the critical value, the retention increased remarkably and was not affected by the environment. Above the critical value, however, the retention of these cements was relatively small and affected considerably by the environment. By water immersion, the increase in the retention was found for the two polyacrylate, but not for the zinc phosphate. Correlation between retention and mechanical strengths of the three cements in the respective environments was indefinite.

Adhesiveness↗
PubMed1980

[The correlation between climacteric symptoms and plasma levels of catecholamines (author's transl)].

Although climacteric symptoms, particularly, vasomotor symptoms such as hot flushes, have been suggested to correlate with depletion of ovarian estrogen secretion, its precise mechanism to producing these symptoms has still remained unknown. On the other hand, catecholamines have been presumed to be related to an onset of the climacteric symptoms. This study was carried out to elucidate the correlation between the climacteric symptoms and plasma levels of catecholamines. Thirty-eight women complaining of climacteric symptoms were studied. These subjects were evaluated for their symptoms and the severity of the symptoms was expressed in numerical figure, 0 to 3, according to its degrees: none, slight, moderate, and marked, respectively. At the same time venous blood samples were drawn to determine the plasma levels of catecholamines, using an Renzini's fluorimetric assay method improved by Miura. Eventually, a correlation between severities of the symptoms and plasma catecholamines was made. Plasma epinephrine levels were found to be elevated as the severity of the hot flush progressed from none to marked. No symptoms other than hot flush showed such significant correlation with plasma epinephrine or norepinephrine levels. This result suggests that the onset of hot flush is closely related with an increased activity of the adrenomedullary sympathetic nervous system.

Adult↗
PubMed1980

Enzyme replacement treatment for Tay-Sachs disease brain cells in culture utilizing concanavalin A-mediated hexosaminidase A uptake: biochemical and morphological evidence of GM2 mobilization.

When Concanavalin A (Con A) is bound to the cell membrane, it functions as an artificial enzyme receptor, mediating the binding and intracellular incorporation of significant amounts of exogenous hexosaminidase A (Hex A) into Tay-Sachs disease (TSD) glia cells. The treated cells retained almost 50% of incorporated Hex A activity after 3 days incubation in Hex A free medium. Hex A was released from Con A within the cell and was available as free enzyme. Biochemical analysis of gangliosides in Con A and Hex A treated cells depicted a greater than 50% reduction in stored GM2 ganglioside and a fourfold reduction in GM2 label (14C) when compared to controls. Ultrastructural evidence of GM2 breakdown is presented which supports the biochemical and labeling studies.

Cell Membrane↗
PubMed1980

The AB-variant of GM2-gangliosidosis. Clinical, biochemical, and pathological studies of two patients.

Clinical, neuropathological, and biochemical studies are reported in two children with the AB-variant of GM2-gangliosidosis. One patient had become symptomatic by 1--1.5 years, initially showing cerebellar signs, and then progressive psychomotor retardation, with hypotonia, spasticity, dementia, and macular cherry red spots, until death at the age of 4.5 years. The second patient showed an earlier onset of retardation and a more rapidly progressive course. At postmortem, the brains were of normal or near normal weights and displayed grossly only mild cerebral cortical and cerebellar atrophy, and mild pallor or attenuation of the white matter. Neuronal storage was widespread throughout the CNS, and both neurons and glia contained a variety of abnormal, membranous inclusions. Visceral organs were not involved. Ganglioside sialic acid was increased several fold in gray matter, with GM2 the predominant ganglioside species. N-acetyl-beta-glucosaminidase activities in serum, leukocytes, fibroblasts, and postmortem gray matter, assayed with an artificial, fluorogenic substrate, were normal, as were activities of other lysosomal hydrolases.

Atrophy↗