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Biomedical subjects

K H Chou

Publications and source records attributed to K H Chou.

10 recordsLinked to original sources
PubMed2003

Suture anchor repair of ulnar-sided triangular fibrocartilage complex tears.

Traditional open repair of traumatic triangular fibrocartilage complex (TFCC) tears requires a relatively extensive exposure, and arthroscopic repair, though conceptually simple, can be technically demanding. We describe a mini-open suture anchor technique that, while minimally invasive, is easier to perform than previously described open or arthroscopic techniques. Results achieved using this technique in eight cases compare favourably with those reported for other techniques.

Adult↗
PubMed2003

Clinical, metabolic and endocrine parameters in response to metformin in obese women with polycystic ovary syndrome: a randomized, double-blind and placebo-controlled trial.

There is still some controversy concerning the effects of metformin in the treatment of Polycystic Ovary Syndrome (PCOS). The aim of this study was to asses the effect of metformin on clinical, metabolic and hormone parameters in obese women with PCOS. Thirty obese, non-diabetic women with PCOS received 500 mg of metformin or placebo, TID, over 90 days. Assessed parameters included body mass index, waist-to-hip ratio, blood pressure, FSH, LH, total testosterone, SHBG, fasting insulinemia, insulin-to-glucose ratio, total, HDL and LDL cholesterol, triglycerides, and menstrual cycles before and after the use of the drugs. Before treatment, patients did not differ in the two groups. After 90 days of metformin use, PCOS women presented significantly lower levels of total testosterone (p = 0.030) and total cholesterol (p = 0.023) compared to the women that used placebo. The other parameters did not differ between the groups. In conclusion, obese women with PCOS may benefit from the use of metformin through the reduction of hyperandrogenemia, total cholesterol, and possibly by restoration of regular menstrual cycles. Further studies with longer follow-ups are necessary to determine cardiovascular and endometrial metformin benefits and insulin-resistance decrease in women with polycystic ovary syndrome.

Adolescent↗
PubMed1985

Structure of a glycolipid reacting with monoclonal IgM in neuropathy and with HNK-1.

An acidic glycolipid antigen that reacts with monoclonal IgM in patients with demyelinating neuropathy and with the mouse monoclonal antibody, HNK-1, was purified from human peripheral nerves. This lipid sharing antigenic determinants with the myelin-associated glycoprotein was shown to be an unusual glucuronic acid-containing sulfated glycosphingolipid with five sugars, but without sialic acid. Mild acid methanolysis converted the GlcUA to its methyl ester, removed the acidic sulfate group and abolished the antigenicity. Results from chemical, enzymatic, infrared, and mass spectral analysis suggested the following structure with a sulfate in a position that remains to be determined: GlcUA beta 1----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1 ceramide.

Antibodies, Monoclonal↗
PubMed1985

Subcellular fractionation of rat sciatic nerve and specific localization of ganglioside LM1 in rat nerve myelin.

Subcellular fractionation of rat sciatic nerve was developed to determine the specific localization of gangliosides in the nerve membrane fractions. Myelin, microsomal, and a plasma membrane-like fraction were isolated and purified by sucrose density gradient centrifugation. These subfractions were characterized by electron microscopy, marker enzyme assays, and their protein and lipid profile. In rat sciatic nerve myelin, 90 mol% of the total gangliosides were monosialogangliosides. LM1 (sialosyl-lactoneotetraosylceramide) (61 mol%) and GM3 (21%) were the major gangliosides of the rat nerve myelin. Two other neolacto series of gangliosides, viz., sialosyl-lactoneonorhexaosylceramide and sialosyl-lactoneooctaosylceramide, were also localized mostly in the myelin fraction. GM1 was only a minor (less than 2%) ganglioside in myelin. The ganglioside patterns of the microsomal and plasma membrane-like fractions were similar with minor quantitative differences and were entirely different from that of myelin. Monosialogangliosides were approximately 70-75 mol% of the total in these fractions. The major gangliosides of the microsomal and plasma membrane-like fractions were GM3 (approximately 40%) and GM1 (approximately 20%). LM1 in these fractions was minimal (less than approximately 5%). Significant amounts of GM3 with N-glycolylneuraminic acid (approximately 10%) and GM1b (4-14%) were also identified in the microsomal and plasma membrane-like fractions but not in myelin. These and the higher lactoneo series of gangliosides have not been previously reported to be present in the rat nervous system. Almost exclusive localization of LM1 in myelin in rat peripheral nervous system is consistent with our previous observation that deposition of LM1 in the nerve with age was very similar to that of myelin marker lipids cerebrosides and sulfatides.

Animals↗
PubMed1981

Neutral glycosphingolipids and ceramide composition of ethylnitrosourea-induced rat neural tumors: accumulation of ceramide in tumors.

Experimental rat neural tumors in offspring were induced transplacentally by a single injection of a chemical carcinogen, ethylnitrosourea, 20 mg/kg body weight, in the tail vein of the mother. The neutral glycosphingolipid, sulfatide, and ceramide composition of the tumors and the normal tissues from which the tumors originated is described. The content of nonhydroxy fatty acid (NFA) and hydroxy fatty acid (HFA) containing ceramide in all the neural tumors so far examined was significantly increased compared with the corresponding normal neural tissue. Some 8 to 18 mol% of total neutral glycolipids was as ceramide in neurinomas, oligodendrogliomas, and meningiomas. Lactosylceramide in normal neural tissues was about 1 mol% of the total neutral glycosphingolipids. In various neural tumors lactosylceramide increased up to 8 mol%. NFA- and HFA-containing cerebrosides constitute 94-100% of the neutral glycosphingolipids in normal neural tissues. In various neural tumors the mol percent of cerebrosides was significantly reduced. A high performance liquid chromatographic method was modified to analyze simultaneously ceramides, cerebrosides, and higher neutral glycosphingolipids.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1980

UDP-galactose-ceramide galactosyltransferase in rat brain myelin subfractions during development.

The localization and activity of the enzyme UDP-galactose-hydroxy fatty acid-containing ceramide galactosyltransferase is described in rat brain myelin subfractions during development. Other lipid-synthesizing enzymes, such as cerebroside sulphotransferase, UDP-glucose-ceramide glucosyltransferase and CDP-choline-1,2-diacylglycerol cholinephosphotransferase, were also studied for comparison in myelin subfractions and microsomal membranes. The purified myelin was subfractionated by isopycnic sucrose-density-gradient centrifugation. Four myelin subfractions, three floating respectively on 0.55 M- (light-myelin fraction), 0.75 M- (heavy-myelin fraction) and 0.85 M-sucrose (membrane fraction), and a pellet, were isolated and purified. At all ages, 70--75% of the total myelin proteins was found in the heavy-myelin fraction, whereas 2--5% of the protein was recovered in the light-myelin fraction, and about 7--12% in the membrane fraction. Most of the galactosyltransferase was associated with the heavy-myelin and membrane fractions. Other lipid-synthesizing enzymes studied appeared not to associate with purified myelin or myelin subfractions, but were enriched in the microsomal-membrane fraction. During development, the specific activity of the microsomal galactosyltransferase reached a maximum when the animals were about 20 days old and then declined. By contrast the specific activity of the galactosyltransferase in the heavy-myelin and membrane fractions was 3--4 times higher than that of the microsomal membranes in 16-day-old animals. The specific activity of the enzyme in the heavy-myelin fraction sharply declined with age. Chemical and enzymic analyses of the heavy-myelin and membrane myelin subfractions at various ages showed that the membrane fraction contained more proteins in relation to lipids than the heavy-myelin fraction. The membrane fraction was also enriched in phospholipids compared with cholesterol and contrined equivalent amounts of 2':3'-cyclic nucleotide 3'-phosphohydrolase compared with heavy- and light-myelin fractions. The membrane fraction was deficient in myelin basic protein and proteolipid protein and enriched in high-molecular-weight proteins. The specific localization of galactosyltransferase in heavy-myelin and membrane fractions at an early age when myelination is just beginning suggests that it may have some role in the myelination process.

Animals↗
PubMed1972

Glutamate dehydrogenase from pumpkin cotyledons: characterization and isoenzymes.

Glutamate dehydrogenase from pumpkin (Cucurbita moschata Pior. cultivar Dickinson Field) cotyledons was found in both soluble and particulate fractions with the bulk of the activity in the soluble fraction. Both enzymes used NAD(H) and NADP(H) but NAD(H) was favored. The enzymes were classified as glutamate-NAD oxidoreductase, deaminating (EC 1.4.1.3). Both enzymes were heat stable, had a pH optimum for reductive amination of 8.0, and were inhibited by high concentrations of NH(4) (+) or alpha-ketoglutarate. The soluble enzyme was more sensitive to NH(4) (+) inhibition and was activated by metal ions after ammonium sulfate fractionation while the solubilized particulate enzyme was not. Inhibition by ethylenediaminetetraacetate was restored by several divalent ions and inhibition by p-hydroxymercuribenzoate was reversed by glutathione. Particulate glutamate dehydrogenase showed a greater activity with NADP. The molecular weights of the enzymes are 250,000. Separation of the enzymes by disc gel electrophoresis showed that during germination the soluble isoenzymes increased from 1 to 7 in number, while only one particulate isoenzyme was found at any time. This particulate isoenzyme was identical with one of the soluble isoenzymes. A number of methods indicated that the soluble isoenzymes were not simply removed from the particulate fraction and that true isoenzymes were found.

Journal Article↗
PubMedDate not supplied

Bony tissue repair.

Bone is among the most frequently injured of tissues, and bony injuries are among the conditions most commonly treated by hand therapists. An understanding of the biology of bony tissue repair, as well as the techniques available for its promotion, is therefore of the utmost importance to practitioners of hand therapy. This article addresses the biology of bony tissue repair, techniques currently available for the treatment of bony injuries, and management of specific bony injuries of the hand.

Bone Transplantation↗