Search PubMed⌕ Search

Biomedical subjects

C H Kuo

Publications and source records attributed to C H Kuo.

At least 163 records · Page 9Linked to original sources

Effects of La+++, Mn++ and ruthenium red on Mg-Ca-ATPase activity and ATP-dependent Ca-binding of the synaptic plasma membrane.

The effects of La+++, Mn++ and ruthenium red (R.R.) on Ca-uptake of synaptic plasma membranes (S.P.M.) were investigated. La+++ (0.1 mM), Mn++ (0.2 mM) and R.R. (0.1 mM) selectively inhibited Mg-Ca-ATPase but did not significantly affect Mg-ATPase activity. The apparent Ki values of La+++, Mn++ and R.R. for Mg-Ca-ATPase were 0.05, 0.06 and 0.03 mM, respectively. La+++, Mn++ and R.R. did not affect Ca-uptake at concentrations which strongly inhibited Mg-Ca-ATPase activity. These results indicate that Ca-uptake by S.P.M. differ from that by sarcoplasmic reticulum.

Adenosine Triphosphatases↗

Bound forms of Ca taken up by the synaptic plasma membrane.

Temperature dependent Ca-binding by the synaptic plasma membrane was increased in the presence of ATP and Mg++. Apparent Km for ATP was about 2.8 X 10(-5) M and optimal concentration of Mg++ was 2 mM in the presence of 2 mM ATP. After preincubation with nonradioactive Ca++, ATP and Mg++ to attain a steady state, addition of 45Ca resulted in remarkable labelling of the membrane, indicating rapid turnover of most of the membrane bound Ca. The presence of oxalate (60 mM) greatly increased Ca up-take on prolonged incubation. The Ca uptake in presence and absence of oxalate had similar substrate specificity and was similarly influenced by various monovalent cations. Furthermore, activities for Ca-uptake in the presence and absence of oxalate could not be separated by sucrose density gradient centrifugation of the synaptic plasma membrane fraction. Accordingly, it was considered that Ca++ in the medium was taken up by surface of the membrane, ATP- and temperature-dependently and then transferred into a cavity where the Ca-oxalate complex is formed.

Adenosine Triphosphate↗

Hydronephrosis accidentally detected by gastrointestinal sonography.

A retrospective study was carried out on patients with gastrointestinal complaints, who were accidentally found to have varying degrees of hydronephrosis between October 1989 and April 1991. The criteria for hydronephrosis given by Ellenbogen et al were used for ultrasonographic diagnosis. Grade 0 and 1 were classified as mild degree and grade 2 and 3 as moderate and severe, respectively. The causes of hydronephrosis were determined by intravenous pyelography, retrograde pyelography, and/or computed tomography. Of 44 patients with hydronephrosis who had complete studies, 20 had a mild degree of hydronephrosis, 18 had a moderate degree, and 6 had a severe degree. All 24 patients with moderate and severe degrees of hydronephrosis had obstruction as the etiology, but only 50% of the cases with mild hydronephrosis were found to have pathological lesions. Urolithiasis (79.4%) was the most common cause of hydronephrosis in this study. Benign prostate hypertrophy, carcinomas, external compression, and tuberculosis followed. Hydronephrosis found accidentally by sonography in the patients with gastrointestinal complaints is significant.

Aged↗