Biomedical subjects
Publications and source records attributed to Wei Shen.
An extracellular alkaline protease produced by Bacillus licheniformis AP-1 was purified 76-fold, yielding a single 28 kDa band on SDS-PAGE. It was optimally active at pH 11 and at 60 degrees C (assayed over 10 min). The protease was completely inhibited by phenylmethylsulfonyl fluoride and diodopropyl fluorophosphate, with little increase upon Ca2+ and Mg2+ addition.
OBJECTIVE: BMI (kilograms per meters squared) and waist circumference (WC) (measured in centimeters) are each associated with the risk of developing cardiovascular disease (CVD). Therefore, a combination of the two may be more effective in identifying subjects at risk than either alone. The present study sought to identify the combination of BMI and WC that has the strongest association with CVD risk factors in whites. RESEARCH METHODS AND PROCEDURES: Subjects were 8712 white men and women from the Third National Health and Nutrition Examination Survey. The optimal combination of BMI and WC was developed using logistic regression models with BMI and WC as predictors and CVD risk factors as outcomes. The combined measure of BMI and WC using current cut-off points was also examined. Sensitivity, specificity, and receiver operating characteristics curves were compared between the combined measures and BMI alone. RESULTS: For white men, the optimal combination of BMI and WC for identifying CVD risk factors was 0.68 x BMI + 0.32 x WC. This combination generated a score that better estimated the odds of having CVD risk factors than either alone. For white women, WC alone largely determined the likelihood of having CVD risks. The combination of BMI and WC using current cut-off points may provide an improved measure of CVD risk. Combined measures showed a higher sensitivity or a shorter distance in receiver operating characteristic curves in the identification of CVD risk factors. DISCUSSION: Combined measures of BMI and WC may provide a higher overall test performance for CVD risk factors and may be useful in some ethnic groups as an improved means of screening subjects for further evaluation in the clinical setting.
BACKGROUND: Body composition differs between African American (AA) and white women, and the resting metabolic rate (RMR) is likely to be lower in AA women than in white women. OBJECTIVE: We tested 2 hypotheses: that AA women have a greater proportion of low-metabolic-rate skeletal muscle (SM) and bone than do white women and that between-race musculoskeletal differences are a function of body weight. DESIGN: Hypothesis 1 was tested by comparing SM, bone, adipose tissue, and high-metabolic-rate residual mass across 22 pairs of matched AA and white women. Magnetic resonance imaging and dual-energy X-ray absorptiometry were used to partition weight into 4 components, and RMR was both calculated from tissue-organ mass and measured. Hypothesis 2 was evaluated by measuring SM, bone, fat, and residual mass in 521 AA and white women with the use of dual-energy X-ray absorptiometry alone. RESULTS: Hypothesis 1: AA women had greater SM ( +/- SD group difference: 1.52 +/- 2.48 kg; P < 0.01) and musculoskeletal mass (1.72 +/- 2.66 kg; P < 0.01) than did white women. RMR calculated from body composition and measured RMR did not differ; RMR estimated by both approaches tended to be lower (approximately 160 kJ/d) in AA women than in white women. Hypothesis 2: SM was significantly correlated with weight, height, age, and race x weight interaction; greater SM in the AA women was a function of body weight. CONCLUSIONS: Lower RMRs in AA women than in white women are related to corresponding differences in the proportions of heat-producing tissues and organs, and these race-related body-composition differences increase as a function of body weight.
BACKGROUND: Visceral adipose tissue (VAT), which is linked with the metabolic consequences of obesity, is usually characterized by measuring VAT area at the L4-L5 vertebral interspace. However, the location of the slice with the strongest relation to VAT volume is not established. OBJECTIVE: We sought to investigate the relations between cross-sectional VAT areas at different anatomic locations and VAT volume in a large, diverse sample of healthy subjects. DESIGN: VAT volume was derived from slice areas taken at 5-cm intervals from magnetic resonance images in 121 healthy men [x +/- SD age: 41.9 +/- 15.8 y; body mass index (BMI; in kg/m(2)): 26.0 +/- 3.2; VAT: 2.7 +/- 1.8 L] and 198 healthy women (age: 48.1 +/- 18.7 y; BMI: 27.0 +/- 5.4; VAT: 1.7 +/- 1.2 L). Regression models were developed to identify the best single slice for estimating VAT volume. RESULTS: The VAT area 10 cm above L4-L5 (A(+10)) in men (R(2) = 0.932, P < 0.001) and 5 cm above L4-L5 (A(+5)) in women (R(2) = 0.945, P < 0.001) had the highest correlation with abdominal VAT. R(2) increased by only 3.8% in men and 0.5% in women with adjustment for age, race, scanning position, BMI, and waist circumference. Studies using A(+10) in men and A(+5) in women will require 14% and 9% fewer subjects, respectively, than those using slices at L4-L5 and will have equivalent power. CONCLUSION: Measurement of slice areas at A(+10) in men and A(+5) in women provides greater power for the detection of VAT volume differences than does measurement at L4-L5.
Lean soft tissue (LST) measured by dual-energy X-ray absorptiometry (DEXA) is used as a metabolic measure in aging research despite evidence of extracellular fluid expansion and a corresponding reduction in body cell mass (BCM) in older participants. We investigated the hypothesis that the fraction of LST as BCM is smaller with greater age. Men and women (n = 2043) had DEXA and 40K-counting for body potassium and BCM measured on the same day. Both BCM and LST were lower with greater age but the relative lowering was larger for BCM. A multiple linear regression model was fitted with BCM/LST as the dependent variable, and age, sex, and interaction terms as independent variables. Men had a mean BCM/LST greater (p < .001) than women; quadratic and cubic age terms were also significant or approached significance. Thus, the fraction of LST as BCM is smaller in older adults, a finding that has implications for the interpretation of DEXA results.
Antibiotic efflux is an important mechanism of resistance in pathogenic bacteria. Here we describe the identification and characterization of a novel chromosomally encoded multidrug resistance efflux protein in Staphylococcus aureus, MdeA (multidrug efflux A). MdeA was identified from screening an S. aureus open reading frame expression library for resistance to antibiotic compounds. When overexpressed, MdeA confers resistance on S. aureus to a range of quaternary ammonium compounds and antibiotics, but not fluoroquinolones. MdeA is a 52-kDa protein with 14 predicted transmembrane segments. It belongs to the major facilitator superfamily and is most closely related, among known efflux proteins, to LmrB of Bacillus subtilis and EmrB of Escherichia coli. Overexpression of mdeA in S. aureus reduced ethidium bromide uptake and enhanced its efflux, which could be inhibited by reserpine and abolished by an uncoupler. The mdeA promoter was identified by primer extension. Spontaneous mutants selected for increased resistance to an MdeA substrate had undergone mutations in the promoter for mdeA, and their mdeA transcription levels were increased by as much as 15-fold. The mdeA gene was present in the genomes of all six strains of S. aureus examined. Uncharacterized homologs of MdeA were present elsewhere in the S. aureus genome, but their overexpression did not mediate resistance to the antibacterials tested. However, MdeA homologs were identified in other bacteria, including Bacillus anthracis, some of which were shown to be functional orthologs of MdeA.
BACKGROUND: Cordeceps sinensis (CS) is a herb which can inhibit the liver fibrosis. Hyperinsulinemia is common in liver cirrhosis patients. The activity of insulin degrading enzyme could reflect the metabolism of insulin. This study was to detect the dynamical effects and mechanisms of CS on the activity of hepatic insulinase in CCl4 induced liver cirrhosis in rats. METHODS: Rats were randomly allocated into three groups: normal group, model group and CS group. The rats in the normal group were sacrificed at the beginning of experiment, and the other two groups were sacrificed randomly at the end of the third, sixth and ninth weeks. Blood and tissue specimens were taken. Biochemical assays were used to determine the changes of alanine transaminase (ALT), albumin levels in serum. And radioimmunological assays were used to determine the changes of hyaluronic acid (HA), insulin levels in serum and the activity of hepatic insulinase. RESULTS: No significant differences were seen in the serum levels of ALT, albumin, HA between the CS group and the model group at the third and sixth weeks (P>0.05). The serum levels of ALT, HA in the CS group were lower than those in the model group at the ninth week (P<0.05), but the serum level of albumin in the CS group was higher than that in the model group at the ninth week (P<0.05). No significant differences were observed in the serum levels of insulin and the activity of hepatic insulinase between the CS and model groups at the third week and the normal group (P>0.05). The serum levels of insulin in the CS and model groups at the sixth and ninth weeks were higher than those in the normal group (P<0.05). But the activity of hepatic insulinase was lower than that in the normal group (P<0.05 or P<0.01). No significant differences were found in the serum levels of insulin and the activity of hepatic insulinase between the CS and model groups at the third, sixth and ninth weeks (P>0.05). CONCLUSIONS: CS may decrease the damage to hepatocyte by CCl4, and inhibit hepatic fibrogenesis. Six weeks after CCl4 administration, the activity of hepatic insulinase began decreasing. CS could not inhibit the decrease of the activity of hepatic insulinase.
OBJECTIVE: This is a study on some ABO subgroup samples which show discordant results of serological and molecular blood typing, the aim is to clarify their true ABO type by means of nucleotide analysis on exons 6 and 7 of their ABO gene. METHODS: Absorb-elution test and family investigation were conducted to study 7 samples which were involved in ABO grouping discrepancies. Duplex polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) method was used to identify their ABO genotypes. PCR products of exons 6 and 7 were cloned and sequenced. RESULTS: All the 7 ABO subgroup samples with the discordant results of serological and molecular blood typing were found to have the normal O gene. Four out of them were typed as ABsub by serology, they were all of the A*102/O genotype. Sequencing analysis found all their A gene having the nt467 (C-->T) and nt803 (G-->C) mutation by comparison with the A*101 allele, i.e. their real type should be CisAB/O. Three out of 7 were typed as AsubB by serology and as BO by genotype; and point mutation was detected in all of their B gene. One of them had the nt700 (C-->G) mutation, the other 2 unrelated individuals had the novel nt640 (A-->G) mutation in their B alleles. CONCLUSION: Through nucleotide analysis, 7 samples have been typed as AB subgroup in serology with the normal O gene, their real ABO type being CisAB in 4 cases and B(A) in 3 cases. At the same time, a kind of novel B (A)640 allele has been uncovered in this study.
OBJECTIVE: To evaluate the therapeutic effect of interferon therapy after transcatheter arterial chemoembolization (TACE) in patients with hepatocellular carcinoma associated with hepatitis B virus. METHODS: Sixty-two patients with advanced primary hepatocellular carcinoma associated with hepatitis B virus was randomly divided into 2 groups. Thirty-one cases were treated with TACE and Interferon. Thirty-one cases with TACE only. HBV DNA, clinical effect, intrahepatic tumor recurrence rate and survival rate were studied. RESULTS: Of the 31 patients in TACE+IFN group, 17 (54.8%) were negative for HBV DNA at the end of treatment. None of TACE group was negative for HBV DNA. The intrahepatic tumor recurrence rate at 1 year and 2 years in TACE+IFN group was 16.1%, 29.0%, compared with 38.7%, 61.3% in TACE group (chi-square = 3.97, chi-square 6.51, P < 0.05). The survival rate in the former was 83.9% and 74.2% respectively, compared with that of 61.3% and 38.7% in the latter (chi-square = 3.97, chi-square = 7.94, P < 0.05). CONCLUSION: Interferon therapy after transcatheter arterial chemoembolization resulted low recurrence and long survival in patients with hepatocellular carcinoma associated with hepatitis B virus. This method showed fewer side effects and should be recommended.
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OBJECTIVE: This is a study on the allele composing of ABO, FUT1 and FUT2 gene loci of 10 para-Bombay individuals in China. METHODS: Ten samples coming from different districts of China were suspected of para-Bombay phenotype by primary serology tests. Routine and absorb-elution tests were conducted to identify their ABO type, and duplex polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied to getting their ABO genotype. Most of them were submitted to a test of their Lewis type as well. Then through direct DNA sequencing with PCR products of FUT1 and FUT2 genes, the genotypes of their H and SE gene loci were analyzed. RESULTS: It can be confirmed that the 10 samples are para-Bombay. All of their ABO genotypes are consistent with the serological absorb-elution results and the substances detected results in saliva. Seven out of 10 have recessive homozygous gene at their H locus. Each phenotype of h1h1 (nt547-552Deltaag), h2h2 (nt880-882Deltatt) and h4h4 (nt35 t-->c) are ascertained in 2 individuals; moreover, h3h3 (nt 658 c-->t) is identified in one individual. The rest are hh heterozygous individuals: one is h3/h(new-1); the other is h2/h(new-2); the last one is h1/h2. The h(new-1) (nt586 c-->t) allele has a point mutation at nt 586 C to T, which leads a nonsense mutation Gln(CAG) to stop (TAG).The second h (new-2) (nt328 g-->a) has an nt328 G to A missense mutation,which leads Ala (GCC),was replaced by Thr (ACC) at 110 amino acid position. All the 10 samples have Se (nt357 c-->t) synonymous mutation. One Bm(h) (B/O) individual with h4h4 phenotype has a Se(w)(nt357 c-->t; nt385 a-->t) allele, whose Lewis type is Le(a+b+). Moreover, the authors detected a (nt716 g-->a) mutation in two samples' Se gene. CONCLUSION: Four kinds of known h alleles (h1-h4), 2 kinds of novel non-functional FUT1 alleles, a Se(w) allele, and a novel SeG716A polymorphism in Chinese para-Bombay individuals were detected. At the same time, the authors noticed that all the 10 samples have the nt357 c-->t mutation in their FUT2 gene.
Although the cloned animals have been successfully generated in a number of mammalian species, there are still many problems about this technology. The developmental aberrancies include a high rate of abortion during early gestation and high rate of perinatal death. The main cause of these problems may be attributed to the epigenetic reprogramming of somatic donor genome. During mammalian embryonic development, DNA methylation is an essential process in the regulation of transcription. There are many aberrant methylation in various genomic regions of cloned embryos. The gene imprinting of cloned embryos are also abnormal.
The genetic relationships between economic traits and genetic markers were studied in 147 goats including Chaidamu goat (CS), Chaidamu Cashmere goat (CRS) and Liaoning Cashmere goat (LRS) in Qinghai province, China. CRS was the population of CSxLRS crossbred. The results showed as follows: the selection reaction of these blood protein polymorphisic loci were great, such as EsD, LAP and P(A-3); and EsD2-2, LAPBB and PA-32-2 were the superior marker genotypes on body weight ,Cashmere yield and Cashmere fineness respectively by Least Square method. The interaction between marker genotypes at double loci was found frequently, and their ratio between interaction variance component and genetic variance was higher. With the method of marker assisted prediction( MAP), some interaction effect could be used effectively in the crossbreed population. On the aspect of random amplified polymorphic DNA (RAPD), the number of the superior RAPD marker bands were 11 on body weight trait, 9 and 6 RAPD marker bands on Cashmere yield and Cashmere fineness. For multi-goal traits, CY0818/A0 type and OPW19/C1 type were superior RAPD markers of body weight and Cashmere yield, CY0818/G1 type was superior one of body weight and Cashmere fineness.
The polymorphism of goat growth hormone gene in 5'-region in 274 goats including Lubei white goat, introducted Boer goat, pure bred Boer goat , hybrid generation 1 of LuBei white goat and Boer goat , backcross of hybrid generation 1 and Boer goat were detected by PCR-SSCP with two different pairs of primers. The result showed that in 26-239bp most of the Boer goats and hybrid generation presented as AA genotype,while most LuBei white goats presented as BB genotype. In 225-429bp all breeds presented as more CC genotype. The amplified fragments of AA,BB and CC,DD of the two fragments were cloned and sequenced . The result showed that in 26-239bp AA genotype had one substitution mutation at 60 site (C-->T), and base C losing at 211 site and DD genotype had three substitution mutations at 264 site (T-->C), 292 site (T-->A) and 372 site (C-->T) in 225-429bp. The results above-mentioned first confirmed that there were polymorphisms in 5' region of GH gene.
The production of recombinant protein is one of the major successes of biotechnology, animal cells are required to synthesize proteins with the appropriate post-translational modifications. Transgenic animal mammary gland bioreactor are being used for this purpose. Gene targeting is a more powerful method to produce mammary gland bioreactor, and nuclear transfer from cultured somatic cells provides an wonderful means of cell-mediated transgensis. Here we describe efficient and reproducible gene targeting in goat fetal fibroblasts to place the human tissue plasminogen activator mutant (ht-PAm) cDNA at the beta-casein locus, and would produce the transgenic goat by nuclear transfer. To construct the gene targeting vector pGBC4tPA, the milk goat beta-casein genomic DNA sequence for homologous arms had been cloned firstly. The left arm was 6.3 kb fragment including goat beta-casein gene 5' flanking sequence, and the right arm was 2.4 kb fragement including beta-casein gene from exon 8 to exon 9. The ht-PAm cDNA was subcloned in the goat beta-casein gene exon 2, and the endogenous start condon was replaced by that of ht-PAm. The bacterial neomycin (neo) gene as positive selection marker gene, was placed in the beta-casein gene intron 7, the thymidine kinase (tk) as the negative selection marker gene, was just outside the right arm. The validity of the positive-negative selection vector (PNS), was tested, and targeting homologous recombination (HR) were elevated to 5-fold with the negative selection marker using the drug GANC. The DNA fragment in which two LoxP sequence was delected effectively using Cre recombinase in vitro. Goat fetal fibroblasts were thawed and cultured to subconfluence before transfection, about 10(7) fibroblasts were electoporated at 240V, 600 microF in 0.8 mL PBS buffer containing linear pGBC4tPA. transfected cells were cultured in collagen-coated 96-wellplate for 24h without selection, then added the drug G418 (600 microg/mL) and GANC (2 micromol/L). After 12 days of selection, well separated G418r/GANCr clones were isolated and expanded in 24-wellplate. 244 clones were selected, and only 90 clones could grow and be tested by PCR screening for targeting. The primary result demonstrated that 31 targeting cell clones with homologous recombination events were obtained, and 2 cell clones was verified by DNA sequence analysis on the homologous recombination region.
Recent advances in imaging techniques and understanding of differences in the molecular biology of adipose tissue has rendered classical anatomy obsolete, requiring a new classification of the topography of adipose tissue. Adipose tissue is one of the largest body compartments, yet a classification that defines specific adipose tissue depots based on their anatomic location and related functions is lacking. The absence of an accepted taxonomy poses problems for investigators studying adipose tissue topography and its functional correlates. The aim of this review was to critically examine the literature on imaging of whole body and regional adipose tissue and to create the first systematic classification of adipose tissue topography. Adipose tissue terminology was examined in over 100 original publications. Our analysis revealed inconsistencies in the use of specific definitions, especially for the compartment termed "visceral" adipose tissue. This analysis leads us to propose an updated classification of total body and regional adipose tissue, providing a well-defined basis for correlating imaging studies of specific adipose tissue depots with molecular processes.
OBJECTIVE: To compare the accuracy of four volume estimation models to actual tissue and organ volumes measured in the visible woman. METHODS: Actual volumes were calculated from 1-mm-thick visible woman images that were segmented for five major components including subcutaneous and visceral adipose tissue across the 1730 available slices. Four available models resolved to two equations: truncated cone/truncated pyramid vs. two-column/parallel trapezium. Between-slice interval and initial slice were systematically varied when deriving component volumes using the two equations in four regions. RESULTS: For each compartment and each between-slice interval, the means of the two-column model were always the same as the corresponding reference volumes, whereas those of the truncated cone model were smaller than the reference volumes. Similarly, the coefficient variation for the two-column model was always smaller than for the truncated cone model. DISCUSSION: The equation based on the parallel trapezium and the two-column models is more accurate in estimating tissue volumes than the corresponding equation for truncated pyramid and truncated cone models. This finding has important implications for the volume calculations of imaging-based body compartments such as adipose tissue.
The eukaryotic regulatory protein 14-3-3 is involved in many important plant cellular processes including regulation of nitrate assimilation through inhibition of phosphorylated nitrate reductase (pNR) in darkened leaves. Divalent metal cations (Me2+) and some polyamines interact with the loop 8 region of the 14-3-3 proteins and allow them to bind and inhibit pNR in vitro. The role of the highly variant C-terminal regions of the 14-3-3 isoforms in regulation by polycations is not clear. In this study, we carried out structural analyses on the C-terminal tail of the Arabidopsis 14-3-3omega isoform and evaluated its contributions to the inhibition of pNR. Nested C-terminal truncations of the recombinant 14-3-3omega protein revealed that the removal of the C-terminal tail renders the protein partially Mg2+-independent in both pNR binding and inhibition of activity, suggesting that the C-terminus functions as an autoinhibitor. The C-terminus of 14-3-3omega appears to undergo a conformational change in the presence of polycations as demonstrated by its increased trypsin cleavage at Lys-247. C-terminal truncation of 14-3-3omega at Thr-255 increased its interaction with antibodies to the C-terminus of 14-3-3omega in non-denaturing conditions, but not in denaturing conditions, suggesting that the C-terminal tail contains ordered structures that might be disrupted by the truncation. Circular dichroism (CD) analysis of a C-terminal peptide, from Trp-234 to Lys-249, revealed that the C-terminal tail might contain a tenth alpha-helix, in agreement with the in silico predictions. The function of the putative tenth alpha-helix is not clear because substituting two prolyl residues within the predicted helix (E245P/I246P mutant), which prevented the corresponding peptide from adopting a helical conformation, did not affect the inhibition of pNR activity in the presence or absence of Mg2+. We propose that in the absence of polycations, access of target proteins to their binding groove in the 14-3-3 protein is restricted by the C-terminus, which acts as part of a gate that opens with the binding of polycations to loop 8.