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Biomedical subjects

K Huang

Publications and source records attributed to K Huang.

At least 199 records · Page 11Linked to original sources
PubMed1976

Effect of clomiphene citrate on serum prolactin in infertile women with ovarian dysfunction.

Serum prolactin (PRL) levels were determined by radioimmunoassay in 12 normal, menstruating women and in 26 infetile women with ovarian dysfunction for one cycle or for about 30 days in amenorrheic women. Galactorrhea was not observed. No significant change in serum PRL levels was observed throughout the normal, menstrual cycle. Of the 26 patients with ovarian dysfunction, seven showed PRL levels higher than normal. Twelve of the 26 patients were treated with clomiphene citrate (Clomid), 100 mg, daily for 5 days. Ovulation occurred in seven, and pregnancy was achi-ved in two of them. Serum PR;, follicle-stimulating hormone, and luteinizing hormone were measured for a preceding control cycle and during the cycle following Clomid treatment in the 12 patients. The serum PRL levels were normal during the control cycle in five of the patients who ovulated with Clomid and high in four patients who failed to ovulate. Although serum PRL levels were not significantly changed by Clomid in the patients who ovulated with the drug, they were markedly decreased during and immediately after Clomid treatment in patients who failed to ovulate with Clomid.

Clomiphene↗
PubMedDate not supplied

The action mode of the ribosome-inactivating protein alpha-sarcin.

Based on the tertiary structure of the ribosome-inactivating protein alpha-sarcin, domains that are responsible for hydrolyzing ribosomes and naked RNA have been dissected. In this study, we found that the head-to-tail interaction between the first amino beta-strand and the last carboxyl beta-strand is not involved in catalyzing the hydrolysis of ribosomes or ribonucleic acids. Instead, a four-strand pleated beta-sheet is indispensable for catalyzing both substrates, suggesting that alpha-sarcin and ribonuclease T1 (RNase T1) share a similar catalytic center. The integrity of an amino beta-hairpin and that of the loop L3 in alpha-sarcin are crucial for recognizing and hydrolyzing ribosomes in vitro and in vivo. However, a mutant protein without the beta-hairpin structure, or with a disrupted loop L3, is still capable of digesting ribonucleic acids. The functional involvement of the beta-hairpin and the loop L3 in the sarcin stem/loop RNA of ribosomes is demonstrated by a docking model, suggesting that the two structures are in essence naturally designed to distinguish ribosome-inactivating proteins from RNase T1 to inactivate ribosomes.

Animals↗
PubMedDate not supplied

The uptake of Na-selenite in rat brain. Localization of new glutathione peroxidases in the rat brain.

Polyunsaturated fatty acids (PUFAs) occur in phospholipids of synapses of central nervous system (CNS). PUFAs may thus determine the fluidity of synaptosomal membranes and regulate neuronal transmission. It was therefore tempting to suggest an oxidative system in CNS protecting the membrane function, e.g., glutathione peroxidase (GSH-Px). In order to trace GSH-Px Wistar rats were loaded with 4800 kBq of 75Se sodium selenite. By means of gradient ultracentrifugation, particulate fractions of CNS were isolated and radioactivity as well as selenium dependent GSH-Px were estimated. The following data were obtained: 1. All fractions (myelin, synaptic vesicles, synaptosomes, mitochondria, and microsomes) contained 75Se. 2. After acetone precipitation of GSH-Px activity, fractionation on Sephadex G-150 revealed in all particulate fractions at least two peaks of radioactivity with GSH-Px activity. 3. The two GSH-Px peaks from the Sephadex filtration were freeze dried and applied on a hydrophobic T-gel column and eluted with decreasing molarity of ammonium sulfate from 1.5 to 0.05M. The first Sephadex peak with GSH-Px activity from myelin and the second peak with GSH-Px activity from synaptic vesicles could now be resolved into two different fractions of radioactivity on the T-gel. The remaining Sephadex G-150 peaks could only be resolved into one peak of radioactivity. 4. SDS-polyacrylamide gel electrophoresis of the T-gel peaks from all fractions showed a protein band with a mobility identical with that of human erythrocyte GSH-Px. The T-gel elution of myelin, synaptic vesicles and mitochondria gave rise to nearly pure CNS GSH-Px activity. The data presented support the idea that CNS fractions have membrane bound GSH-Px activity that may function as protecting enzymes towards oxidative stress in the brain.

Animals↗
PubMedDate not supplied

Selenium-containing peroxidases of germinating barley.

Germinating barley grown on an artificial medium was exposed to 75Se-selenite for 8 d. Then the leaves were homogenized and proteins were separated by means of Sephadex G-150 filtration, followed by DEAE-Sepharose chromatography. Each fraction collected was assayed for total protein, radioactivity, and peroxidase activity. In barley leaves, three protein peaks (peaks no. I, II, and III) with peroxidase activity could be separated by Sephadex G 150 filtration. Each fraction was then further separated on DEAE-Sepharose chromatography. Thus, peaks I and II were resolved by DEAE-Sepharose into one major and two minor peaks of radioactivity. However, only the major peak showed peroxidase activity. Peak III was resolved from the gel filtration on the DEAE-sepharose into one major and four minor peaks of radioactivity. The major and three of the minor radioactivity peaks contained peroxidase activity. The protein fractions were separated by polyacrylamide gel electrophoresis. The molecular weights of separated proteins were estimated by means of molecular markers, and 75Se radioactivity was evaluated by autoradiography. Thus, gel filtration peak I contained four bands with mol wts of 128, 116, 100, and 89 kDa. Of these, the 89 kDa protein contained selenium. Peak II contained three protein bands with mol wts 79.4, 59.6, and 59.9. The 59.6 band was a selenoprotein. Peak III contained four protein bands (and some very weak bands). The four major bands had mol wts of 38.6, 31.6, 30.2, and 29.2 kDa. The last mentioned band was a selenoprotein.

Animals↗
PubMedDate not supplied

Alterations in the biorheological features of some soft tissues after limb lengthening.

The aim of this study was to investigate the effects of a surgical limb lengthening procedure on the biorheological features of some lengthened soft tissues. In this procedure external fixators were applied to goats' right radius to stretch the tissues. The right forelegs of goats were lengthened by 2, 4 cm, respectively. After lengthening ceased, the goats were examined after different periods of time. The lengthened median nerves, arteries and veins were harvested and used to study their biorheological features. Tensile strength of lengthened and control specimens were measured and their stress relaxation features and stress-strain relationships were studied. Results showed that at the beginning of recovery, the stress-strain curves, relaxation curves and tensile strengths of the lengthened specimens began to deviate from those of their controls. However, with increasing recovery time, the curves and tensile strength of the lengthened specimens reverted to those of their controls. All the tissues studied exhibited the same behavior.

Animals↗
PubMedDate not supplied

Chemical composition and microstructure of uroliths and urinary sediment crystals associated with the feeding of high-level cottonseed meal diet to water buffalo calves.

The chemical composition and microstructure of seven uroliths and four urinary sediment samples associated with the feeding of high-level cottonseed meal diet to buffalo calves were examined by chemical qualitative analyses, scanning electron microscopy (SEM), X-ray diffraction, and X-ray energy dispersive spectrometry (EDS). Struvite was a major component of kidney stones and of some bladder stones. The kidney stone sample appeared cracked under low power under SEM, aggregated into tiny balls under high power, and as a blade-like structure under even higher power. The bladder stone samples appeared finely granular or granular with various forms of prismatic crystals. The urinary sediments were prismatic crystals, with granules. The newly found prismatic crystals, which were rich in potassium and similar to struvite in crystal structure, were identified as potassium magnesium phosphate (KMgPO4.6H2O) in some bladder stones and urinary sediments. However, crystals which contained Mg and P only, which had been used for struvite identification, were not found by EDS examination in urinary sediments from fresh urine samples of buffalo calves fed the high-level cottonseed meal diet.

Animals↗
PubMedDate not supplied

Drug use behaviors among Asian drug users in San Francisco.

Due to a pervasive bias toward Asian Americans, such as tendency to view Asian Americans as model minorities, drug use behaviors among them are often ignored by health professionals, researchers, and community members, including Asian community members. This study identified patterns of drug use behaviors in relation to cultural factors among Asian drug users in San Francisco, CA. A sample of 92 Asian drug users (35 Chinese, 31 Filipino, 26 Vietnamese) who were not currently enrolled in drug treatment programs were recruited through targeted sampling methods and interviewed using a questionnaire with open-ended questions. The study evaluated responses of the participants and used content analyses. This study clearly revealed that the patterns of drug use among Asian drug users are unique to their ethnicity, gender, immigrant status, and age groups. Also, Asian drug users share cultural constructs related to drug use such as fear of addiction and injecting drugs, and stigma attached to drug users in the community. Therefore, drug abuse prevention programs should address both common factors among Asian drug users, as well as unique factors in specific target groups (e.g., ethnic groups, Asian immigrants, Asian women, refugees, and adolescents).

Adult↗
PubMedDate not supplied

The next generation of liposome delivery systems: recent experience with tumor-targeted, sterically-stabilized immunoliposomes and active-loading gradients.

Three topics are discussed. Enhanced anti-tumor efficacy of targeted doxorubicin-containing sterically-stabilized liposomes using an anti-beta1 integrin Fab' ligand. Use of tumor targeting with an internalizing ligand to improve the efficacy of a non-leaky cisplatin-containing sterically-stabilized liposome formulation. Formulation variables (remote-loading with dextran ammonium sulfate, rigid lipid bilayer) used to optimize in vivo performance of a liposomal camptothecin analog.

Ammonium Sulfate↗
PubMedDate not supplied

Peripheral lymph node-specific and Peyer's patch-specific homing receptors are differentially regulated following lymphocyte activation.

The MEL-14 receptor (MEL-14 R) expressed by murine lymphocytes represents the peripheral lymph node-specific homing receptor, and is essential for murine lymphocytes to specifically adhere to high endothelial venules (HEV) of the peripheral lymph nodes and to ultimately migrate in vivo into the parenchyma of this lymphoid organ. A Peyer's patch-specific homing receptor, termed LPAM, is now appreciated to mediate murine lymphocyte adhesion to Peyer's patch HEV. We previously demonstrated that the cell surface density of the MEL-14 R was markedly reduced following PMA-induced protein kinase C activation of lymphocytes. In the present study, we investigated the phenotypic and functional expression of LPAM by murine lymphocytes exposed to PMA. The results show that the surface expression of LPAM on activated lymphocytes remains constant under conditions where MEL-14 R is downregulated significantly. Additionally, the surface expression of LPAM is not influenced by calcium ionophore, either alone or in combination with PMA, whereas the PMA-induced loss of MEL-14 R is synergized by calcium ionophore. Therefore, LPAM and MEL-14 R expression are differentially regulated by activated murine lymphocytes. LPAM expressed by TK1 (Peyer's patch HEV-binding murine lymphoma) and MEL-14 R expressed by 38C13 (peripheral lymph node HEV-binding murine lymphoma) were found to be regulated by the consequences of PMA activation in a pattern similar to that of normal lymphocytes. Furthermore, we provide evidence that MEL-14 R internalization is not involved in the loss of the receptor expressed by activated lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗