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Biomedical subjects

F Yang

Publications and source records attributed to F Yang.

At least 73 records · Page 4Linked to original sources
PubMed2001

Decreased renal expression of nitric oxide synthase isoforms in adrenocorticotropin-induced and corticosterone-induced hypertension.

Administration of adrenocorticotropic hormone (ACTH) leads to the development of hypertension. Because glucocorticoids can affect the nitric oxide system at several sites, the present study tested the hypothesis that nitric oxide synthase (NOS) expression may be altered in ACTH-induced and corticosterone-induced hypertension in the rat. This was addressed by measuring Nos1, Nos2, and Nos3 mRNA in the kidney, adrenal gland, heart, and hypothalamus of 16 ACTH-treated and 16 vehicle-treated rats as well as in 10 corticosterone-treated and 10 control rats. In addition, in situ hybridization and immunohistochemistry were used to confirm changes by detection of Nos in RNA and NOS protein in tissues. Systolic blood pressure of ACTH and corticosterone rats was elevated (165+/-6 and 162+/-11 mm Hg; P<0.001 versus control). Each Nos isoform mRNA was measured by reverse transcriptase-polymerase chain reaction technique. In ACTH rats, mRNA for Nos2 was reduced in renal cortex by 58+/-5% and in medulla by 68+/-7%; for Nos3, mRNA reductions of 59+/-6% and 51+/-11% were seen (P<0.001 after Hochberg correction for multiple comparisons). In corticosterone rats, Nos2 mRNA decreased in cortex by 68+/-5% and in medulla by 62+/-6%; Nos3 mRNA by 50+/-8% in cortex, and Nos1 by 29+/-7% in medulla (all P<0.001 after Hochberg correction). Reductions seen in kidney were supported by in situ hybridization and immunohistochemistry. Apart from a 62+/-2% decrease in Nos2 mRNA in adrenal of ACTH rats (corrected P<0.05), no significant changes were seen in the other nonrenal tissues for any isoform. In conclusion, we have shown for the first time that the physiological components of glucocorticoid action (ACTH and corticosterone) when given chronically in vivo reduce Nos2 and Nos3 expression in the kidney. Such changes are consistent with a role in hypertension for ACTH and corticosterone.

Adrenocorticotropic Hormone↗
PubMed2001

Haptoglobin in lung defence.

Haptoglobin (Hp) has been known to be associated with the host defence response to infection and inflammation. The biological functions of Hp can be related to its ability to bind haemoglobin or to modulate immune response. Hp is expressed at a high level in lung cells, yet its protective role(s) in the lung is not known. Using transgenic mice overexpressing Hp, we demonstrated that Hp can reduce blood-induced lung injury. Hp-mediated haemoglobin catabolism in lung cells appears to be linked to iron mobilization, and may be an efficient mechanism to reduce oxidative damage associated with haemolysis.

Animals↗
PubMed2001

Nesprins: a novel family of spectrin-repeat-containing proteins that localize to the nuclear membrane in multiple tissues.

In search of vascular smooth muscle cell differentiation markers, we identified two genes encoding members of a new family of type II integral membrane proteins. Both are ubiquitously expressed, and tissue-specific alternative mRNA initiation and splicing generate at least two major isoforms of each protein, with the smaller isoforms being truncated at the N-terminus. We have named these proteins nesprin-1 and -2 for nuclear envelope spectrin repeat, as they are characterized by the presence of multiple, clustered spectrin repeats, bipartite nuclear localization sequences and a conserved C-terminal, single transmembrane domain. Transient transfection of EGFP-fusion expression constructs demonstrated their localization to the nuclear membrane with a novel C-terminal, TM-domain-containing sequence essential for perinuclear localization. Using antibodies to nesprin-1, we documented its colocalization with LAP1, emerin and lamins at the nuclear envelope, and immunogold labeling confirmed its presence at the nuclear envelope and in the nucleus where it colocalized with heterochromatin. Nesprin-1 is developmentally regulated in both smooth and skeletal muscle and is re-localized from the nuclear envelope to the nucleus and cytoplasm during C2C12 myoblast differentiation. These data and structural analogies with other proteins suggest that nesprins may function as 'dystrophins of the nucleus' to maintain nuclear organization and structural integrity.

Amino Acid Sequence↗
PubMed2001

C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase gene: incidence and effect of combined genotypes on plasma fasting and post-methionine load homocysteine in vascular disease.

BACKGROUND: Moderately increased plasma concentrations of total homocysteine (tHcy) have been shown to be an important risk factor for vascular diseases. Two common polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene, the thermolabile C677T and a more recently reported A1298C polymorphism, may contribute to hyperhomocysteinemia. METHODS: Using PCR and restriction fragment length polymorphism analysis, we studied the prevalence of the C677T and A1298C MTHFR genotypes and the combined effect of these polymorphisms on plasma tHcy concentrations, as measured by HPLC with fluorometric detection, both fasting and post-methionine load (PML), in 1238 individuals. RESULTS: The prevalences of the C677T and A1298C genotypes did not differ significantly in 772 individuals with documented coronary artery disease (CAD), 137 individuals with deep-vein thrombosis (DVT), and 329 individuals without documented vascular disease. Individuals homozygous for the 677T allele had significantly increased fasting tHcy, particularly in the presence of low folate, compared with individuals homozygous for the wild-type allele. Neither the 1298AC nor the 1298CC genotype was associated with significantly increased fasting or PML tHcy concentrations irrespective of serum folate. Of the nine combined MTHFR genotypes, six were present in >10% of the population. Of these, the difference in mean fasting tHcy reached statistical significance (P<0.005) only in individuals with the 677TT/1298AA genotype compared with individuals with the wild-type 677CC/1298AA genotype. Differences in mean fasting tHcy did not reach statistical significance in individuals heterozygous for both MTHFR variants. We detected two 677CT/1298CC and three 677TT/1298AC individuals; only one, an 677TT/1298AC individual, had increased tHcy (both fasting and PML). No individuals had the 677TT/1298CC genotype. CONCLUSIONS: The prevalences of the C677T and A1298C polymorphisms did not differ among individuals with CAD, DVT, or those without documented vascular disease. In contrast to the C677T polymorphism, the A1298C polymorphism is not associated with increased fasting tHcy. Although the two polymorphisms usually exist in trans configuration, crossover may occur rarely to form recombinant chromosomes.

Adult↗
PubMed2001

An X-Y paint set and sperm FISH protocol that can be used for validation of cattle sperm separation procedures.

X and Y chromosome paints were developed from sorted yak chromosomes for sexing cattle spermatozoa. Clear hybridization signals were obtained for every spermatozoon using a modified sperm decondensation protocol and fluorescence in situ hybridization (FISH). The procedure was evaluated using the established Beltsville sperm sexing technology, which separates spermatozoa by flow cytometry into X- and Y-bearing fractions. Close agreement was found between the assessment of sperm separation by flow cytometry and by FISH with the X-Y paint set. The FISH method is a simple, reliable and robust procedure for assessing the effectiveness of separation of X and Y spermatozoa.

Animals↗
PubMed2001

[Evaluation on the effect of synthetic hydroxyapatite for drinking water defluoridation in field study].

In order to evaluate the effect of synthetic hydroxyapatite on drinking water defluoridation, a coagulative precipitation method and a flow column system was tested in the fields. The defluoridation capacity of coagulative precipitation method was 4.19 mg/g, and the method was simple on operation, but more reagents were needed with high cost for operation. The defluoridation capacity of flow column system was 6 mg/g and the saturated hydroxyapatite could be reused after regeneration. The operation of household defluoridator based on flow column system is simple, with low cost and high capacity in defloridation. The system will be applied in the fluorosis areas.

Durapatite↗
PubMed2001

Comparison of global brain gene expression profiles between inbred long-sleep and inbred short-sleep mice by high-density gene array hybridization.

BACKGROUND: Inbred long-sleep (ILS) and short-sleep (ISS) mice show significant central nervous system-mediated differences in sleep time for sedative dose of ethanol and are frequently used as a rodent model for ethanol sensitivity. In this study, we have used complementary DNA (cDNA) array hybridization methodology to identify genes that are differentially expressed between the brains of ILS and ISS mice. METHODS: To carry out this analysis, we used both the gene discovery array (GDA) and the Mouse GEM 1 Microarray. GDA consists of 18,378 nonredundant mouse cDNA clones on a single nylon filter. Complex probes were prepared from total brain mRNA of ILS or ISS mice by using reverse transcription and 33P labeling. The labeled probes were hybridized in parallel to the gene array filters. Data from GDA experiments were analyzed with SQL-Plus and Oracle 8. The GEM microarray includes 8,730 sequence-verified clones on a glass chip. Two fluorescently labeled probes were used to hybridize a microarray simultaneously. Data from GEM experiments were analyzed by using the GEMTools software package (Incyte). Differentially expressed genes identified from each method were confirmed by relative quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: A total of 41 genes or expressed sequence tags (ESTs) display significant expression level differences between brains of ILS and ISS mice after GDA, GEM1 hybridization, and quantitative RT-PCR confirmation. Among them, 18 clones were expressed higher in ILS mice, and 23 clones were expressed higher in ISS mice. The individual gene or EST's function and mapping information have been analyzed. CONCLUSIONS: This study identified 41 genes that are differentially expressed between brains of ILS and ISS mice. Some of them may have biological relevance in mediation of phenotypic variation between ILS and ISS mice for ethanol sensitivity. This study also demonstrates that parallel gene expression comparison with high-density cDNA arrays is a rapid and efficient way to discover potential genes and pathways involved in alcoholism and alcohol-related physiologic processes.

Alternative Splicing↗
PubMed2001

[Analysis of association between gene polymorphisms of microsomal epoxide hydrolase (EPHX1) and infant birthweight].

We investigated association between genetic polymorphisms of EPHX1 in mother and infant birthweight. Data of 342 female workers were collected in textile mill. A total of 342 mothers were genotyped for the His139Arg polymorphism of EPHX1 by a polymerase chain reaction-restriction fragment length polymorphism assay. Using multiple linear regression models, we estimated the adjusted association between polymorphisms of EPHX1 and birthweight, with adjusted for potential confounders. We found that polymorphisms of EPHX1 were closely associated with reduced birthweight (beta +/- SE = -149 g +/- 56, P = 0.0083) after adjustment for major cofounders. In subgroup of passive smoking analysis, the polymorphisms of EPHX1 were highly associted with birthweight for those with passive smoking (beta +/- SE = -234 g +/- 88, P = 0.0088); The significant association of EPHX1 polymorphisms with reduced birthweight were showed for those with working stress (beta +/- SE = -157 g +/- 59, P = 0.0079). Our data provide polymorphisms of EPHX1 in mothers were significant association with birthweight of their infant, and showed gene-environmental interaction in relation to birthweight.

Birth Weight↗
PubMed2001

The green tea polyphenol (-)-epigallocatechin-3-gallate blocks nuclear factor-kappa B activation by inhibiting I kappa B kinase activity in the intestinal epithelial cell line IEC-6.

The I kappa B kinase complex (IKK) mediates activation of the transcription factor nuclear factor-kappa B (NF-kappa B). We previously showed that green tea polyphenols inhibited endotoxin-mediated tumor necrosis factor-alpha (TNF alpha) production by blocking NF-kappa B activation. In this study, we evaluated whether green tea polyphenols inhibit NF-kappa B by blocking IKK activity. We assessed IKK activity by detecting changes in phosphorylation of an I kappa B alpha-glutathione S-transferase (GST) fusion protein. IEC-6 cells pretreated with an extract of green tea polyphenols (GrTPs; 0--0.4 mg/ml) had diminished TNF alpha-induced IKK and NF-kappa B activity. Of the various GrTPs, (-)-epigallocatechin-3-gallate (EGCG) was the most potent inhibitor. We next examined whether EGCG inhibited activated IKK. In cytosolic extracts of TNF alpha-stimulated cells, EGCG inhibited phosphorylation of I kappa B alpha-GST (IC(50) > 18 microM) consistent with inhibition of IKK activity. Using other polyphenols, we showed that the gallate group was essential for inhibition, and antioxidants were ineffective in blocking activated IKK. Importantly, EGCG decreased IKK activity in cytosolic extracts of NIK transiently transfected cells. This latter finding showed that our findings were not related to nonspecific kinase activity. In conclusion, EGCG is an effective inhibitor of IKK activity. This may explain, at least in part, some of the reported anti-inflammatory and anticancer effects of green tea.

Animals↗
PubMed2001

Nontoxic doses of suramin enhance activity of doxorubicin in prostate tumors.

We recently reported that acidic and basic fibroblast growth factors (aFGF and bFGF) confer a broad-spectrum chemoresistance in solid tumors, and that inhibitors of these proteins enhanced the antitumor activity of several anticancer drugs. The present study investigated the effect of FGF inhibitors on doxorubicin activity in human prostate PC3 tumors. In in vitro studies, conditioned medium (CM) obtained from histocultures of rat MAT-LyLu lung metastases and different combinations of recombinant FGF induced a 7- to 15-fold doxorubicin resistance. Suramin had no effect on the doxorubicin activity in the absence of CM or FGF, but reversed the CM- and FGF-induced resistance by > or =90% at concentrations that had no cytotoxicity (i.e., 1-17 microM suramin). In the in vivo study, immunodeficient mice bearing well established, subcutaneous PC3 tumors (approximately 100 mg in size) were treated intravenously with doxorubicin (5 mg/kg) and suramin (10 mg/kg), administered twice weekly for 3 weeks. The suramin dose, selected to yield plasma concentration of below 50 microM, had neither antitumor activity nor toxicity. Doxorubicin alone reduced tumor growth rate by approximately 60%, reduced the density of nonapoptotic tumor cells by approximately 60%, enhanced the apoptotic cell fraction by 4-fold, and reduced the body weight by approximately 15% (p < 0.05 compared with control). Addition of suramin to doxorubicin therapy did not increase weight loss but significantly enhanced the antitumor effect, resulting in complete inhibition of tumor growth, an additional 3-fold reduction in the density of nonapoptotic tumor cells, and an additional 2-fold enhancement of the apoptotic tumor cell fraction (p < 0.05 compared with all other groups). These data indicate significant enhancement of the effectiveness of doxorubicin in prostate tumors by nontoxic and subtherapeutic doses of suramin.

Algorithms↗
PubMed2001

[Application of surface plasmon resonance in molecular biology].

The application of surface plasmon resonance (SPR) in molecular biology was reviewed. The biomolecular interaction can be detected with SPR in real time and in situ without the use of labels, the association and dissociation can be monitored continuously, and multi-component complex interaction can be followed step by step. The applications of the SPR in the fields of molecular biology, demonstrated the advantage of this technique that couldn't achieved by the routine techniques.

DNA Replication↗
PubMed2001

[Relationship between EGG and the dynamic process of motion sickness induced by optokinetic vection].

OBJECTIVE: To investigate the correlation between Electrogastrography (EGG) and the occurrence of nausea or/and vomit as well as the development of motion sickness (MS) induced by optokinetic stimulation (OPS) and to provide a clue and method for prediction and prevention of MS. METHOD: Twenty male subjects, aged from 18 to 25 years, performed the test only once with the optokinetic drum rotated around a vertical axis at the speed of 60 degrees/s for 15 min. Nausea and EGG signals were observed and recorded. RESULT: (1)Both the increment of tachygastric percentage and the decrement of primary wave percentage of EGG in eleven subjects with nausea were significantly larger than those in nine subjects with no nausea (both P < 0.001). (2)The circular vection preceded the changes of EGG in eleven subjects with nausea while the MS scores in eleven subjects with nausea were higher than those in nine subjects with no nausea (P < 0.001). (3)During the rotation of drum, the decrement of primary wave percentage or the increment of tachygastria percentage also preceded the occurrence of nausea in eleven subjects with nausea (both P < 0.01). CONCLUSION: (l)The changes of EGG in subjects with nausea were significantly greater than those of EGG in subjects with no nausea. (2)There was a close relationship between circular vection or illusory self-rotation and EGG changes as well as the occurring of nausea induced by OPS. (3)Changes of EGG preceded the nausea of MS induced by OPS.

Adolescent↗
PubMed2001

[Acceptability and feasibility of promoting condom use among families with human immunodeficiency virus infection in rural area of China].

OBJECTIVE: To study the acceptability and feasibility of promoting condom use among families with human immunodeficiency virus (HIV) infection in rural area of China. METHODS: Ninety families with HIV infection were selected. Education, skill training on condom use and distribution of condoms were carried out. Two cross-sectional surveys were carried out before and after intervention to compare the difference of condom use rate. RESULTS: Eighty-four families finished the study, with a follow-up rate of 93.3%. The rate of use condom for every sexual intercourse in the last month increased from 2.6% before intervention to 71.4% after intervention (P < 0.001). After controlling other confounders, intervention is a strong independent predictor for increased condom use in infected couples. CONCLUSION: Promoting condom use among families with HIV infection in the rural area is acceptable. To reduce risk of sexual transmission of HIV within couples, families of the HIV infected persons need to be informed in no time.

Adult↗
PubMed2001

[Evaluation on peer education program among injecting drug users].

OBJECTIVE: To reduce risk behaviors which promotes human immuno deficiency virus (HIV) transmission among drug users. METHODS: A peer education program was implemented among drug users in drug detoxification centers in Kunming from May 1998 to June 2000. Before and after intervention, through random sampling, subjects were recruited to assess the impact of the program. Focus group discussion and a small sample of follow-up in communities were used for evaluation. RESULTS: Three hundred and six and 418 subjects were interviewed before and after the intervention program. Rates regarding "sharing needles" had a reduction from 68.3% to 62.0% (chi 2 = 2.61, P < 0.01, while "never cleaning a needle" increased from 3.3% to 15.8% (chi 2 = 19.41, P < 0.01), and "used needles disposal to garbage bin" increased from 58.4% to 81.8% (chi 2 = 40.23, P < 0.01). Thirty-four drug users were followed in their communities and 67.6% were no longer sharing needles but none reported using a condom when having casual sex. CONCLUSION: Peer education program among drug users in detoxification centers had limited impact. In order to control the epidemic of AIDS in drug using population, more effective strategies need to be explored.

Evaluation Studies as Topic↗
PubMed2001

[A prospective study on the effects of low-osmolar and nonionic contrast media on renal functions].

OBJECTIVE: To investigate the effects of contrast medium, especially large dose of Iopromide, on renal functions. METHODS: 100 hospitalized patients who were going to have cardiac or renal angiography were selected. 96 patients had normal renal functions and 4 had slightly abnormal renal functions. Scr, Ccr, urine gamma-GT and urine glucose were monitored on the first, third and fifth day after angiography. RESULTS: All the 100 patients were administered with Iopromide. Of the 96 patients with normal renal functions, all had elevated urine gamma-GT on the first day after giving Iopromide; the level returned to normal on the third day. There was no significant change of Scr and Ccr after angiography. Of the 4 patients with abnormal renal functions, all had significant change of Scr and Ccr after using Iopromide and the levels of both returned to pre-angiography level on the fifth day. CONCLUSIONS: In patients with normal renal functions, Iopromide may cause transient elevation of urine gamma-GT level and positive urine glucose. In patients with slightly abnormal renal functions, Iopromide may cause significant decrease of Ccr and increase of Scr. However, with proper treatment, these indexes may return to pre-angiography level on the fifth day after angiography.

Adolescent↗
PubMed2000

Separation of tanshinones from Salvia miltiorrhiza Bunge by high-speed counter-current chromatography using stepwise elution.

High-speed counter-current chromatography (HSCCC) was successfully used for isolation and purification of tanshinones from the roots of Salvia miltiorrhiza Bunge by stepwise elution. A set of three solvent systems and other experimental conditions were determined by analytical HSCCC. Using the optimized conditions, the preparative HSCCC separation was performed on 50 mg of crude light petroleum extract yielding pure tanshinones of tanshinone HA (7 mg), tanshinone I (3 mg) and cryptotanshinone (4 mg) all at purities of over 95% in a single run.

Abietanes↗