Biomedical subjects
Publications and source records attributed to S Yuan.
Phytolaccatoxin is one of the main toxic constituents in Radix Phytolaccae. In this communication, the quantity of phytolaccatoxin is determined by TLC-scanning method. Convenient, rapid and dependable, the method can be used to control the quality of Radix Phytolaccae.
The contents of histamine in processed Phytolacca americana has been determined by colorimetry. The result shows that the contents tend to decrease by 23.3% when the herb is shredded, but get a bit higher again when fried with vinegar. The method may be useful in the quality control of the herb.
A sampling survey of medical exposure frequency covered 15,000 hospitals in 24 provinces, while a sampling measurement of patient doses covered 2,000 hospitals in 14 provinces. From these surveys and measurements, we compiled survey data of 11 million cases. The data were analyzed by computer, and the frequencies, averages of skin and organic dose per examination, and population doses per capita (He, LSD, GSD, SSD) were found. The possible risks of medical exposure in China are also estimated in this paper.
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Highly purified sarcolemma from dog and pig cardiac muscle has been shown to contain significant activities of a membrane-bound cyclic AMP-dependent protein kinase. In addition, these membranes undergo endogenous phosphorylation when incubated with Mg2+ and [gamma-32P]ATP. By comparing 32P-labelled patterns obtained with [gamma-32P]ATP and the photoaffinity label 8-azidoadenosine 3':5'-[32P]monophosphate (8-azido-cyclic [32P]AMP), we have demonstrated that, whereas the major kinase isoenzyme in dog sarcolemma was Type II, that in the pig membrane was the Type I isoenzyme.
Cardiac sarcolemma was purified from canine ventricles. Enrichment of the sarcolemmal membranes was demonstrated by the high (Na+ + K+)-ATPase activity of 28.0 +/- 1.5 mumol Pi/mg protein per h and the high concentration of muscarinic receptors with the Bmax of 8.2 +/- 2.5 pmol/mg protein as determined by [3H]QNB binding. The purified sarcolemma also contains significant levels of a membrane-bound Ca2+ and phospholipid-dependent protein kinase (protein kinase C). To elucidate the protein kinase C activity in sarcolemma, a prior incubation of the membranes with EGTA and Triton X-100 was necessary. The specific activity of protein kinase C was found to be 131.4 pmol Pi/mg per min, in the presence of 6.25 micrograms phosphatidylserine and 0.5 mM CaCl2. Treatment of sarcolemma with 12-O-tetradecanoylphorbol 13-acetate (TPA) and phorbol 12,13-dibutyrate (PBu2) resulted in a concentration-dependent activation of protein kinase C activity. The effect of TPA and PBu2 on protein kinase C in sarcolemma was independent of exogenous Ca2+ and phosphatidylserine. Polymyxin B inhibited phorbol-ester-induced activation of protein kinase C activity. The distribution of protein kinase C in the cytosolic fraction was also examined. The specific activity of the kinase in the cytosolic fraction was 59.7 pmol Pi/mg per min. However, the total protein kinase C activity in the cytosol was 213500 pmol Pi/min, compared to that of 1025 pmol Pi/min in the sarcolemma isolated from approx. 100 g of canine ventricular muscle. Several endogenous proteins in cardiac sarcolemma were phosphorylated in the presence of Ca2+ and phosphatidylserine. The major substrates for protein kinase C were proteins of Mr 94 000, 87 000, 78 000, 51 000, 46 000, 11 500 and 10 000. Most of these substrate proteins have not been identified before. Other proteins of Mr 38 000, 31 000 and 15 000 were markedly phosphorylated in the presence of Ca2+ only. Phosphorylation of phospholamban (Mr 27 000 and 11 000) was also stimulated in the presence of Ca2+ and phosphatidylserine, but the low Mr form of phospholamban was distinct from two other low Mr substrate proteins for protein kinase C. Polymyxin B was more selective in inhibiting the protein kinase C dependent phosphorylation. On the other hand, trifluoperazine selectively inhibited the phosphorylation of phospholamban and Mr 15 000 protein. Although the exact function of this kinase is unknown, based on these observations, we believe that protein kinase C in the cardiac sarcolemma may play an important role in the cell-surface-signal regulated cardiac function.
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To a purely inseparable Galois field extension C over A we associate a certain differential polynomial ring D. We show that all central simple A-algebras that contain C as a maximal commutative subalgebra can be obtained from D by factoring out certain ideals determined by Witt vectors.
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An IR/RAMAN spectra simulation system is reported. The development of this software was based on the substructure/subspectrum relationships established for four different structural classes: small molecules, special fragments, atom-centered FRELs, and bond-centered FRELs (FREL: Fragment centered on an Environment which is Limited). Four corresponding knowledge-bases (now, at a pilot stage) are constructed from usual correlation charts or data analyses of large populations of compounds using data mining techniques.