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Biomedical subjects

B Huang

Publications and source records attributed to B Huang.

At least 127 records · Page 7Linked to original sources
PubMed1997

Anti-human immunodeficiency virus (anti-HIV) natural products with special emphasis on HIV reverse transcriptase inhibitors.

This review article aims at summarizing research findings concerning natural products which are endowed with the ability to inhibit human immunodeficiency virus (HIV). An emphasis is placed on HIV reverse transcriptase inhibitors because the bulk of the literature is focused on these compounds. It was found that a spectacular diversity of chemical structures encompassing proteins, terpenoids, coumarins, xanthones, alkaloids, flavonoids, polyphenols, and polysaccharides, which are elaborated by plant species as phylogenetically remote as the algae, gymnosperms and angiosperms, were capable of rendering the retroviral enzyme less active. The literature pertaining to natural products with HIV protease and integrase inhibitory activities is less voluminous.

Anti-HIV Agents↗
PubMed1997

Bnm1, a Brassica pollen-specific gene.

cDNA and genomic clones of a new pollen-specific gene, Bnm1, have been isolated from Brassica napus cv. Topas. The gene contains an open reading frame of 546 bp and a single intron of 362 bp. A comparison of the deduced amino acid sequence with sequences in data banks did not show similarity with known proteins. Northern blot analysis of developing pollen showed that Bnm1 mRNA was first detected in bicellular pollen and accumulated to higher levels in tricellular pollen. Bnm1 mRNA was not detected in leaves, stems, roots, pistils, seeds or pollen-derived embryos. RNA in situ hybridization of whole flower buds confirmed that Bnm1 was pollen-specific and expressed late in development. A promoter fragment of the Bnm1 gene fused to the gusA reporter gene yielded similar patterns of tissue specificity and developmental regulation in transgenic B. napus cv. Westar plants; however, the promoter was also active during the early stages of pollen development. The Bnm1 gene, cloned in this study, was derived from the A genome of the allotetraploid species B. napus (AACC). Southern blot analysis indicated that sequences similar to the Bnm1 gene were found in both A and C Brassica genomes. Related sequences were found in all 10 members of the Brassiceae tribe examined, but were not present in all tribes of the Brassicaceae family.

Brassica↗
PubMed1997

Associations of adiposity with prevalent coronary heart disease among elderly men: the Honolulu Heart Program.

OBJECTIVE: To assess associations of adiposity with prevalent coronary heart disease (CHD) among elderly men. DESIGN: A cross-sectional epidemiologic study conducted between 1991 and 1993. SUBJECTS: 3741 Japanese-American men from the Honolulu Heart Program who were 71-93 y of age. MEASUREMENTS: CHD included documented myocardial infarction (electrocardiographic and enzyme criteria), acute coronary insufficiency, angina pectoris leading to surgical treatment identified through hospital surveillance, and reported history of heart attach or angina pectoris requiring hospitalization or surgical treatment. BMI was calculated as weight in kg divided by height in square meters. Waist circumference was measured at the horizontal level of the umbilicus and WHR was a ratio of waist circumference to hip circumference measured at the horizontal level of the maximal protrusion of the gluteal muscles. RESULTS: An elevated prevalence of CHD was observed in the elderly men with high BMI, WHR and waist circumference. The significant associations of BMI and waist circumference with CHD persisted after adjustment for fasting glucose, physical activity and pack-years of cigarette smoking but were no longer significant (odds ration (OR) = 1.03, 95% confidence level (CI) 0.94-1.12 and OR = 1.09, CI = 0.99-1.20, respectively) after adjustment for high density lipoprotein cholesterol (HDL-C). Also, the association of BMI with CHD was not found to be independent of abdominal adiposity. However, the associations of WHR and waist circumference remained significant (OR = 1.20, CI = 1.08-1.33 and OR = 1.17, CI = 1.01-1.37, respectively) after additional adjustment for BMI. In addition, the association of WHR with CHD was consistently significant and independent of fasting glucose, physical activity, smoking and HDL-C (OR = 1.11, CI = 1.00-1.23). CONCLUSION: WHR is associated with CHD independent of HDL-C and BMI, whereas the relation of BMI and waist circumference with CHD may be mediated through a relation of BMI and waist circumference with HDL-C level.

Aged↗
PubMed1997

[The cloning, expression, purification and bioactivity identification of recombinant IGF-I].

The fragment containing IGF-I cDNA and cyc1 terminator from PSK-IGF-I plasmid was cloned into PSK43 SB treated by Hind III, Klenow and Cla I, generating a recombinant PSB-IGF-I (DH), which have double Hind III sites. This plasmid was treated by Hind III and Klenow, ligated to give a recombinant plasmid PSB-IGF-I(NH), which has no Hind III site. After analysed by restriction endonucleases and sequencing, the fusion site was verified to be correct. This plasmid was excised and a BamH I-Cla I fragment containing yeast alpha-factor promotor, leader sequence, IGF-I cDNA and cycl terminator was cloned into yeast episomal plasmid vector YEpHC8, generating a recombinant plasmid YEpHC8-IGF-I. Transformed this plasmid into yeast competence cells BJ1990 by using LiAc method. The expressed products were secrected into the medium broth and having the correct molecular weight of 8,100 on SDS-PAGE. The products of IGF-I were raised by using high-cell-density fermentation of Saccharomyces cerevisiae. The cleared supernatant of yeast medium was applied to Bio-Rex 70 resin, eluted with 1 mol/L ammonium acetate, pH8.0. Main peak was pooled and applied to Bio-Gel P10 (200-400 mesh). The second peak was collected and get relatively pure IGF-I proteins. The biological activities of IGF I product was assayed in NIH3T3 cells by using MTT method. The results show that the expressed IGF-I can obviously stimulate NIH3T3 cells to proliferate at the concentration ranging from 10 ng/ml to 50 ng/ml, suggesting that the protein has its biological activities.

3T3 Cells↗
PubMed1997

[Erythropoietin gene cloning and expression in S. cerevisiae].

Mature human erythropoietin gene was amplified from EPO cDNA by PCR methods. The PCR product was cloned into pUC18 plasmid at Sma I site, then precisely engineered into a intermidiate vector pSK43SB which were digested with Hind III, Mung bean nuclease, and Sal I. Then degest pSK43SB-EPO plasmid with EcoR I and Cla I, the EC fragment with an alpha-factor leading sequence, EPO gene and CYC1 terminater were produced. It was then cloned into a typical high efficiency episomal expression vector YEpHC8. Human EPO protein with highly mannose glycosylated was identified by Western blot methods in both secreted and in cells proteins. N-Glycosidase F digested secreted EPO can produce 20,000 EPO without N-glycosylation similar with that produced in cells.

Amino Acid Sequence↗
PubMed1997

[Analysis of single cells by capillary electrophoresis].

A review with 46 references is given on the application of capillary electrophoresis to the analysis of single cells. Injection modes, detectors and future prospects of this microseparation technique for single-cell analysis are described in detail.

Animals↗
PubMed1997

[Determination of Ni, Al, Mn and Si in copper based alloy by high current and microsecond pulsed glow discharge optical emission spectrometry].

The determination of Ni, Al, Mn and Si in copper based alloy by high current and microsecond pulsed (HCMSP) glow discharge optical emission spectrometry (GD-OES) has been reported. With the laboratory built experiment set-up, the factors effecting analytical performance have been studied. The results of sample analysis are in good agreements with the recommendation values, and the stansard deviation for six determinations were 2.66% for Ni, 2.17% for Mn, 6.02% for Si, 1.00% for Al respectively.

English Abstract↗
PubMed1997

[Enhanced emission spectra of Yb, Eu, Y and Sm HCLS with high current microsecond pulsed supply].

The emission spectra of Yb, Eu, Y, Sm hollow cathode lamps have been investigated with a high current microsecond pulsed (HCMP) supply developed in our laboratory. Both atomic and ionic emission lines of interest of these rare earth elements are enhanced by tens to tens of thousand times in HCMP mode compared to DC mode. Effects of parameters of the supply on emission intensities are surveyed. HCMP HCLs may be used as an economic and convenient excitation source for atomic/ionic fluorescence spectrometric analysis.

English Abstract↗
PubMed1997

[Progress in determination of rare earths by atomic/ionic fluorescence spectrometry].

The progress of determination of rare earths by atomic/ionic fluorescence spectrometry is reviewed. The experimental systems and the analytical characteristics of the technique are briefly discussed, and its applications are illustrated in detail. The research trends are predicted as well. The systems with appropriate combinations of excitation sources and atomization/ionization cells are well proved to increase analytical sensitivity and minimize interferences. For the excitation soures, hollow cathode lamp has been proved to be economic and practical, although pulsed dye laser has been intensively investigated. The inductively oupled plasma is a preferable atomization/ionization cell. The atomic/ionic fluorescene spectrometry is one of effective techniques for the determination of rare earths mainly due to its low spectral interference and wide linear dynamic range.

English Abstract↗
PubMed1997

[Determination of the content for micronomicin sulfate by ultraviolet spectrophotometric derivatization].

An ultraviolet spectrophotometric method for determination of micromonicin (MCR) was developed by the reaction of MCR with o-pathaldehyde (OPA) and obtained a derivative absorbing ultraviolet in special wave length. The comparison was made between this method and high performance liquid chromatography (HPLC). The results indicate that the method is simple, rapid, precise and reproducible.

Aminoglycosides↗
PubMed1996

Primary structure and tissue-specific expression of human beta-hydroxyisobutyryl-coenzyme A hydrolase.

beta-Hydroxyisobutyryl-CoA (HIBYL-CoA) hydrolase is responsible for the specific hydrolysis of HIBYL-CoA, a saline catabolite, as well as the hydrolysis of beta-hydroxypropionyl-CoA, an intermediate in a minor pathway of propionate metabolism. We have obtained the amino acid sequences of several tryptic peptides derived from purified rat liver HIBYL-CoA hydrolase, and the NH2-terminal peptize sequence was matched to the translated sequence of a human expressed sequence tag present in the data base of the IMAGE Consortium (Lawrence Livermore National Laboratory, Livermore, CA). The complete nucleotide sequence and the deduced amino acid sequence showed no similarity to the sequences of well known thioesterases but showed significant homology to the enoyl-CoA hydratase/isomerase enzyme family. The cDNA fragment corresponding to the mature (processed) protein was expressed in Escherichia coli. The purified recombinant enzyme displayed substrate specificity very similar to that of the rat enzyme and was specifically bound by polyclonal antibodies raised against purified rat liver HIBYL-CoA hydrolase. Northern and Western blot analyses with various human tissues indicated predominant expression in liver, heart, and kidney, with discrepancies occurring in the amounts of HIBYL-CoA hydrolase mRNA compared to stably expressed protein in several tissues.

Amino Acid Sequence↗
PubMed1996

Acculturation and prevalence of diabetes among Japanese-American men in Hawaii.

The association between acculturation to a Western lifestyle and prevalence of diabetes was examined among 8,006 Japanese-American men in Hawaii with varying degrees of exposure to traditional Japanese social and cultural lifestyles in 1965-1968. A reduced prevalence of diabetes was observed among the men who had retained a more Japanese lifestyle. These men also reported higher levels of physical activity and consumed more carbohydrates and less fat and animal protein in their diet. An inverse association between diabetes and being born in Japan was observed independent of age, body mass index, physical activity, and percentages of calories from fat or carbohydrates (odds ratios = 0.67 and 0.66, 95% confidence intervals 0.49-0.93 and 0.48-0.91, respectively). The number of total years lived in Japan was inversely associated with prevalent diabetes after controlling for age, body mass index, and physical activity (odds ratio = 0.81, 95% confidence interval 0.68-0.96). Current Oriental diet (compared with Western diet) was inversely associated with prevalent diabetes after controlling for age, body mass index, and physical activity (odds ratio = 0.71, 95% confidence interval 0.50-0.98). These findings suggest that living a Japanese lifestyle is associated with a reduced prevalence of diabetes.

Acculturation↗
PubMed1996

Phospholipase A2 engineering. Deletion of the C-terminus segment changes substrate specificity and uncouples calcium and substrate binding at the zwitterionic interface.

It has been suggested [Dijkstra, B. W., Drenth, J., & Kalk, K. H. (1981) Nature 289, 604-606] that the interfacial binding site of phospholipase A2 (PLA2) involves a large number of residues, including a cluster at the N-terminus and another cluster at the C-terminus. The approaches of multiple mutation and deletion were used to test the roles of the C-terminal residues of bovine pancreatic PLA2 overexpressed in Escherichia coli. A double mutant K120A/K121A and a deletion mutant delta 115-123/ C27A were constructed, and structural and functional analyses were performed on both mutants. The double mutant showed little perturbation in the global structure on the basis of proton NMR and X-ray crystallographic analyses. The proton NMR analysis of the deletion mutant suggested that a few residues at the active site, the hydrophobic channel, and the calcium binding loop are perturbed, but the global conformation is not changed. The mutants were then characterized for catalytic and binding properties by use of various kinetic and spectroscopic methods. The double mutant behaved in a manner similar to that of the wild type (WT) PLA2 in every property examined. The deletion mutant was found to show an interesting change of substrate specificity. The kcat,app of the zwitterionic DC8PC micelles but not the anionic DC8PM micelles decreased by a factor of > 100; however, the activity of DC8PC was restored upon addition of 4 M NaCl. The results of fluorescence spectroscopic studies indicate that the deletion mutant behaves in a manner similar to that of WT in the binding to anionic vesicles and to zwitterionic neutral diluent. Thus, the binding affinity of the enzyme to the interface (the E to E* step) should not be the main cause for the change in substrate specificity. The cause lies at least partially in the binding of substrate or inhibitor to the active site of the enzyme at the interface, i.e., the E* to E*L step, as revealed by the results of equilibrium binding studies. The equilibrium dissociation constants of ligands are generally higher for the deletion mutant (relative to WT) at the zwitterionic interface but not at the anionic interface. The cause for the low affinity of an active site-directed ligand to the active site at the zwitterionic interface could be related to the inability of Ca2+ to enhance ligand binding for the deletion mutant. This is in contrast to the WT PLA2 for which Ca2+ binding enhances binding of the substrate to the active site. Overall, the structural and functional perturbations caused by deleting the C-terminal segment are modest, but the changes in substrate specificity and the uncoupling between substrate and calcium binding are interesting and significant.

Amino Acid Sequence↗
PubMed1996

Fish intake may limit the increase in risk of coronary heart disease morbidity and mortality among heavy smokers. The Honolulu Heart Program.

BACKGROUND: Research has shown that fish consumption limits damage to the lungs caused by cigarette smoking, possibly by the effects of fish on arachidonic acid metabolism. We explored this fish-smoking interaction using coronary heart disease (CHD) incidence and mortality as the outcome. METHODS AND RESULTS: The Honolulu Heart Program began in 1965 to follow a cohort of 8006 Japanese-American men aged 45 to 65 years who lived on Oahu, Hawaii, in 1965. Fish intake was measured at baseline by use of a questionnaire. For current smokers at baseline (n = 3310) who reported low fish intake (< 2 times/wk), age-adjusted 23-year CHD mortality rates increased with the number of cigarettes smoked per day (2.3, 3.1, and 6.9 per 1000 person-years for men who smoked < 20, 20 to 30, and > 30 cigarettes/d, respectively; trend test P < .0001). Among current smokers whose fish intake was high (> or = 2 times/wk), CHD mortality rates showed no relation with cigarettes/d (3.7, 3.2, and 3.7 per 1000 person-years for the corresponding levels of smoking). A Cox proportional hazards model based on current smokers, adjusted for age, years in Japan, calories/d, alcohol intake, physical activity index, years smoked, hypertension, and serum cholesterol, blood glucose, and uric acid levels, was examined. In the high-smoking group, the risk factor-adjusted relative risk (RR) for CHD mortality among those with high fish intake was half that of those with low fish consumption (RR = 0.5, 95% confidence interval = 0.28 to 0.91). A Cox model that adjusted for similar risk factors confirmed a significant interaction of cigarettes/d and fish intake (P < .01) on CHD mortality. Analyses for CHD incidence showed similar results. CONCLUSIONS: Despite the findings of this investigation, the public health message for smokers continues to be to stop smoking. However, an interaction between fish intake and cigarette smoking is biologically plausible and deserves further investigation. The study of this phenomenon may shed light on the biological mechanisms by which cigarette smoking leads to CHD.

Aged↗
PubMed1996

Suppression subtractive hybridization: a method for generating differentially regulated or tissue-specific cDNA probes and libraries.

A new and highly effective method, termed suppression subtractive hybridization (SSH), has been developed for the generation of subtracted cDNA libraries. It is based primarily on a recently described technique called suppression PCR and combines normalization and subtraction in a single procedure. The normalization step equalizes the abundance of cDNAs within the target population and the subtraction step excludes the common sequences between the target and driver populations. In a model system, the SSH technique enriched for rare sequences over 1,000-fold in one round of subtractive hybridization. We demonstrate its usefulness by generating a testis-specific cDNA library and by using the subtracted cDNA mixture as a hybridization probe to identify homologous sequences in a human Y chromosome cosmid library. The human DNA inserts in the isolated cosmids were further confirmed to be expressed in a testis-specific manner. These results suggest that the SSH technique is applicable to many molecular genetic and positional cloning studies for the identification of disease, developmental, tissue-specific, or other differentially expressed genes.

Base Sequence↗
PubMed1996

Mutations in human CD4 impair the functional interaction with different human and mouse class II isotypes and alleles.

The structure-function of the CD4-class II MHC interaction was investigated. Two functional assays were used to assess the responses of the 3DT52.5.8 murine T cell hybridoma expressing human CD4 (h-CD4) or murine CD4 (m-CD4). First, we determined the responses of the CD4+ and CD4-effector cells toward DAP-3 cells co-expressing the cognate alloantigen H-2Dd together with several human (DRw52b, DR4-Dw4, DR2A, and DPw2) and murine (I-Ab, I-Ak, IA alpha b I-A beta k and I-Ek) class II alleles and isotypes. We found that h-CD4 and m-CD4 strongly enhance the T cell response to H-2Dd, demonstrating that interspecies CD4/class II interactions occur efficiently. Furthermore, mutations in h-CD4 at positions 19, 89, and 165 markedly reduced the interaction with both human class II and mouse class II, indicating that the structural features of this cross-species interaction are strongly conserved. This was further supported by the finding that a h-CD4 deletion mutant (deletion F43-S49) interacted with both human and murine class II. Moreover, as 3DT cells express the responsive V beta element for the bacterial superantigen staphylococcal enterotoxin B, a co-receptor assay was conducted. DAP-3 cells expressing only class II molecules were used as APCs to present staphylococcal enterotoxin B to h-CD4+ and m-CD4+ T cells. h-CD4 and m-CD4 were able to enhance the T cell response to staphylococcal enterotoxin B, further demonstrating the conservation of the CD4-class II MHC interaction.

Alleles↗