Biomedical subjects

C Yang

Publications and source records attributed to C Yang.

At least 181 records · Page 10Linked to original sources

PubMed2000

Association analysis of variants in the core promoter region of angiotensinogen gene with essential hypertension in Tibetan population.

OBJECTIVE: To detect the variants in the core promoter region of angiotensinogen(AGT) gene, and to analyse the relationship between the AGT gene polymorphisms and essential hypertension in Tibetan population. METHODS: This is a case-control study consisting of 103 essential hypertensive subjects and 82 normotensive controls matched by age and sex. The variants in the AGT gene core promoter region were screened by polymerase chain reaction/single strand conformation polymorphism(PCR/SSCP) and further identified by automated sequencing. The A(-6)G polymorphism was determined in DNA extracted from leucocytes by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). RESULTS: (1) There were two different electrophoresis band patterns in PCR/SSCP analysis. PCR product direct sequencing showed that the two band patterns represented the AA, AC genotypes in the (-20) site of AGT gene respectively. The distribution of A(-20)C genotype was almost identical in essential hypertensive and normotensive groups (P>0.8). The A allele frequency was very high in both groups (control: 0.9175, hypertensive: 0.9124). (2)Distribution of genotype in the (-6) site of AGT gene was much different between the patient group and control group (P<0.005). The frequency of G allele was statistically higher in the patient group than in controls (0.374 vs 0.220, P<0.025). CONCLUSION: Both Tibetan hypertensives and normotensives have higher frequency of A allele in AGT gene (-20) site. The higher frequency of G allele in the AGT gene (-6) site in Tibetan hypertension patients suggests that this allele may be the genetic susceptibility factor in the proceeding of essential hypertension in the Tibetan population.

Angiotensinogen↗

PubMed2000

[Comparative studies of different carriers and introducing routes on the effects of liver targeted uptake of exogenous gene].

OBJECTIVE: To compare the effects of liposomes and glyco-poly-L-lysine (G-PLL) on target uptake and gene expression of the liver, and to observe the effects of intravenous route and intraperitoneal route on target uptake and gene expression of the liver. METHODS: After encapsulated by liposomes or galactose-terminal glyco-poly-L-lysine, the plasmid which can be expressed in eukaryotic cells was transferred into rat's body by intravenous injection and peritoneal injection respectively, then observed the results in different time by in situ hybridization and immunohistochemistry. RESULTS: The expression of the plasmid encapsulated by liposomes or G-PLL was obvious after transferred in vivo 24 h later, and one week later the expression began to decrease, but still could be found three weeks later. Both liposomes and G-PLL made the liver as the major distribution tissue. In the liver, the distribution and expression of the plasmid encapsulated by G-PLL were higher than those encapsulated by liposomes; in other tissues, however, the distribution and expression of the plasmid encapsulated by G-PLL were lower than those by liposomes. The distribution and expression of the plasmid transferred via intravenous route were higher in the liver than that transferred via intraperitoneal route. CONCLUSION: The effect of G-PLL on liver target uptake and expression is better than that of liposome; The effect of intravenous route on liver target uptake and expression of the plasmid binding to G-PLL is better than that of peritoneal route.

Animals↗

PubMed2000

Biotransformation of the anti-angiogenic compound SU5416.

SU5416 [3-(3,5-dimethyl-1H-pyrrol-2-ylmethylene)-1, 3-dihydro-indol-2-one], an inhibitor of VEGF (vascular endothelial growth factor) receptor tyrosine kinase, Flk-1/KDR (fetal liver kinase 1/kinase insert domain-containing receptor), also known as VEGF receptor 2 (VEGFR2) is in advanced clinical trials for treatment of AIDS-related Kaposi's sarcoma and colorectal and nonsmall cell lung cancers. Since this chemical class has not been studied previously with therapeutic intent, the present study was designed to investigate the in vitro metabolism of SU5416 by mouse, rat, dog, monkey, and human liver microsomes and to identify the major metabolites of SU5416. An HPLC procedure was developed and validated to resolve and quantify SU5416 and its metabolites. To evaluate the in vitro metabolism of SU5416, pooled liver microsomes from mice, rats, dogs, monkeys, and humans were incubated with SU5416 (25 microM) in the presence of an NADPH-generating system. In the presence of NADPH, mouse, rat, dog, monkey, and human liver microsomes converted SU5416 to at least 12, 9, 9, 7, and 6 polar metabolites, respectively. Microsomal metabolism of SU5416 showed marked species differences in the levels of different metabolites formed. The overall rate of SU5416 metabolism by liver microsomes from the species examined followed the rank order: monkey > or = mouse approximately rat > dog > human. Two major metabolites of SU5416 were identified, a hydroxymethyl derivative of SU5416 (M12) and a carboxylic acid derivative of SU5416 (M6), by spectroscopic methods and comparison with authentic compounds. Both of these oxidative metabolites were further metabolized in vivo through glucuronidation. The metabolic fate of SU5416 in microsomes from various species as well as data from in vivo biotransformation in the rat are discussed.

Angiogenesis Inhibitors↗

PubMed2000

Regulation of tyrosine hydroxylase gene transcription by the cAMP-signaling pathway: involvement of multiple transcription factors.

The conversion of L-tyrosine to 3,4-dihydroxy-L-phenylalanine by tyrosine hydroxylase (TH) is the first and rate-limiting step in biosynthesis of catecholamine neurotransmitters. TH gene expression is regulated in a cell type-specific and cAMP-dependent manner. Evidence from this laboratory and others indicates that the cAMP response element (CRE), residing at -45 to -38 bp upstream of the transcription initiation site, is essential for both basal and cAMP-inducible transcription of the TH gene. To understand the control mechanisms of TH gene transcription in greater detail, we sought to identify and characterize the transcription factors involved in recognition and activation of the CRE of the TH gene. Remarkably, electrophoretic mobility shift assay and antibody supershift experiments indicated that all three major CRE-binding protein factors, i.e. CREB, ATF1, and CREM, may participate in forming specific DNA/protein complexes with the CRE of the TH gene. To address the transcriptional activation function of individual factors, we replaced the TH CRE with a GAL4-binding site and cotransfected this modified TH promoter-reporter gene with an effector plasmid that encodes GAL4-fused transcription factor. Our results indicate that CREB but not ATF1 can support basal promoter activity while both can robustly induce the promoter activity in response to co-expression of the catalytic subunit of cAMP-dependent protein kinase (PKA). We further show that the coactivator CBP up-regulates PKA-mediated activation of the TH promoter and, if tethered to the TH promoter by a GAL4-fusion, can robustly transactivate the TH promoter even in the absence of PKA. Collectively, our results suggest that multiple CRE-binding factors interact with the CRE and regulate, in conjunction with the coactivator CBP, the transcriptional activity of the TH gene.

Activating Transcription Factor 1↗

PubMed2000

[Use of high-field nulear magnetic resonance spectroscopy for the analysis of stereoselective metabolites of ibuprofen (R)-enantiomer in rat urine].

AIM: To study the metabolic chiral inversion and chiral metabolites of R-(-)-ibuprofen. METHODS: Following administration of R-(-)-ibuprofen (250 mg.kg-1), analysis was performed on rat urine purified extracts obtained by solid phase extraction onto C-18 bonded silica gel, then the metabolites of ibuprofen were detected and identified by 1HNMR spectroscopy. RESULTS: Except for a little ibuprofen, there were 2'-hydroxy-ibuprofen and its glucuronide, 1'-carboxy-ibuprofen glucuronide and ibuprofen glucuronide in rat urine. 2'-hydroxy-ibuprofen is the main metabolite. 1'-carboxy-ibuprofen glucuronide and ibuprofen glucuronide were diastereoisomers. CONCLUSION: There was the phenomenon of metabolic chiral inversion, whereby the R-enantiomer is transformed in vivo to its active S-antipode via an unusual process.

Animals↗

PubMed2000

[Detection and significance of plasminogen activator inhibitor in synovial tissue, synovial fluid and plasma from patients with rheumatoid arthritis].

OBJECTIVE: To study the distribution and expression of type-1 plasminogen activator inhibitor (PAI-1) and type-2 plasminogen activator inhibitor (PAI-2) in synovial tissue from rheumatoid arthritis(RA) and measure the antigen levels and activity in synovial fluid and plasma of patients with RA. METHODS: Immunohistochemical analysis was used to detect PAI-1 and PAI-2 expression and distribution in synovial tissue from 24 RA patients, 18 osteoarthritis (OA) patients and 6 normal subjects. PAI-1 and PAI-2 antigen concentration and activity were determined with ELISA sandwich method. RESULTS: In RA patients, positive staining of PAI-1 and PAI-2 was seen respectively in all the 24 cases and 8 of the 24 cases; positive expression was distributed mainly in the synovial lining area. In OA patients, positive staining of PAI-1 was detected in 8 cases and its positive distribution was similar to that in RA. No PAI-2 positive staining was seen in all the OA cases. In 6 normal subjects with normal synovial tissue, the staining was negative. The concentration and activity of PAI-1 in RA synovial fluid(SF) were significantly higher than those in the plasma(P < 0.001 and P < 0.05). The concentration and activity of PAI-1 in the plasma of RA were also much higher than those in the plasma of OA(P < 0.05 and P < 0.0001) and healthy subjects(P < 0.0001 and P < 0.001). The concentration and activity of PAI-1 in SF and plasma of RA correlated positively. CONCLUSION: The up-regulated expression of PAI-1 and PAI-2 and the concentration and activity of PAI-1 in SF and plasma were significantly higher in RA than those in OA and healthy subjects, suggesting PAI especially PAI-1 may play an important role in the pathogenesis of RA.

Adolescent↗

PubMed2000

[Influence of plant species diversity on productivity of sandy grassland in Kerqin Region].

The relationship between species diversity indices and sandy grassland productivity was studied in Kerqin sandy land, and the results showed that the relations could be divided in to two categories based on the indices and productivity. The first type includes function and composition diversities, their maximal biomass varied form 299 to 336 g.m-2, and had a simple linear relation with the productivity. Their correlation coefficient was remarkably significant. The species richness and Shannon-Wiener indices attribute to second type, their maximal biomass varied from 426 to 433 g.m-2, and had a complex parabola relations with the productivity. Their correlation coefficient was also significant. Meanwhile, the grey correlation analysis showed that the species composition diversity index was the most important factor that influences productivity. According to the grey correlation degree, the order of the different indices affecting productivity was: composition diversity(0.74), function diversity (0.72), species richness (0.66) and Shannon-Wiener index (0.14). It is suggested that increasing plant species richness (species introduction) and consequent composition diversity could be the practices of improving the degraded grassland in Kerqin.

Biomass↗

PubMed2000

[Study on treatment of eczema by Chinese herbal medicine with anti-type IV allergic activity].

OBJECTIVE: To study Chinese herbal prescription for treatment of eczema based on the suppressive effect of Chinese herbal medicine on type IV allergic reaction. METHODS: Various formulae composed of Chinese herbal medicines possessing suppressive effect on allergic contact dermatitis were formed based on the therapeutic principles of traditional Chinese medicine in treating eczema, and their effect on murine ear swelling, ear flake weight, dermal inflammatory infiltration cell count and plasma level of calcitonin gene related peptide (CGRP) were examined in mice with dinitrofluorobenzene induced dermatitis. A prescription, Composite Poria Decoction was formulated and made into granule form, which was used to treat 63 cases of eczema (atopic dermatitis was excluded), and compared with 59 cases treated with antihistamine that was aimed at the type I allergic reaction. RESULTS: Experimental study showed that all the 4 Chinese prescriptions had the effect of anti-type IV allergic reaction, among them, the formula for cooling blood, remove Heat, Wind and Dampness evil possessed the most potent effect in suppressing murine dermatitis, and it was also able to up-regulate the plasma CGRP concentration. The clinical cure rate of Composite Poria Granule treatment was 47.6%, and that of control was 22.0%, the difference was significant between the two groups (u = 2.9555, P < 0.01). CONCLUSIONS: Chinese herbal medicine has effect of anti-type IV allergic reaction. Composite Poria Granule has good effect in treating eczema.

Animals↗

PubMed2000

[Clinical types of pheochromocytom].

OBJECTIVE: To improve the diagnosis and treatment of pheochromocytoma. METHODS: 90 patients with pheochromocytomas were treated from June 1987 to August 1998. These patients showed extra-adrenal (14 patients), non-symptomatic (5), recurrent (8), malignant (15), bilateral or multiple (4), and familial or MEN-IIA (5). RESULTS: One patient with malignant extra-adrenal pheochromocytoma showed extensive metastasis. All the patients except this patient were confirmed pathologically. 36 patients were followed up for 5 months - 10 years. Eight patients had recurrence and 3 showed malignancy. CONCLUSIONS: Open surgery is an effective method for pheochromocytoma. Preoperative preparation must be sufficient to make the operation safe. Recurrent pheochromocytomas are not malignant in nature, but they have considerable malignant tendency and should undergo intensive surveillance and regular examinations. Familial pheochromocytomas are bilateral or multiple. They could develop into secondary medullar thyroid carcinoma in the meantime.

Adolescent↗

PubMed2000

[Middle-aged and elderly patients with hydronephrosis induced by ureteric obstruction: etiology and diagnosis].

OBJECTIVE: To improve the etiologic diagnosis of middle-aged and elderly patients with ureteric obstruction. METHODS: The etiology and diagnosis were retrospectively studied in 141 middle-aged and elderly patients with hydronephrosis in recent 10 years. RESULT: 59 patients had ureterolithiasis, 51 ureteric cancer, 11 ureteric tuberculosis, 9 UPJ stricture, 6 uretero-cyst and 5 ureteric polyp. CONCLUSIONS: Ureterolithiasis and ureteric cancer contribute greatly to ureteric obstruction in middle-aged and elderly patients. Etiologically, B ultrasonography is suggested to be used as the first choice in diagnosis and follow-up of the middle-aged and elderly patients with hydronephrosis, especially those accompanied with hematuria.

Aged↗

PubMed2000

[Prognostic factors of clinical curative effect for malignant obstructive jaundice].

OBJECTIVE: To explore prognostic factors for clinical treatment of patients with malignant obstructive jaundice. METHODS: 17 variables from 216 consecutive patients with malignant obstructive jaundice admitted from 1990 to 1997 were included for statistical analysis. RESULTS: The overall mortality was 19.9% (43/216), and the morbidity 37.5% (81/216). The morbidity of radical operation was higher than that of palliative operation (P < 0.01). There was a highly significant correlation between mortality, morbidity, ASA grade and duration of jaundice (P < 0.01). No correlation was seen between the mortality, type of operation and cause of jaundice. There was a highly significant correlation between the morbidity and the type of operation. CONCLUSIONS: The choice of operation in patients with malignant obstructive jaundice is radical operation. Early diagnosis and choice of treatment are essential to improving carative effect.

Adult↗

PubMed2000

[Effects of excessive iodine on apoptosis and expression of bcl-2, bax genes in the cells of brain and thyroid gland in guinea pigs].

OBJECTIVE: To investigate the effects of excessive iodine intake on apoptosis and the expression of bcl-2, bax genes in the cells of brain and thyroid gland. METHODS: Guinea pigs, divided into two groups at random, were fed with distilled water containing iodine 50 microg/L (a control group with appropriate iodine) and 10,000 microg/L (a trial group with excessive iodine), respectively for six months. Apoptosis rate and expression of bcl-2, bax gene in the cells of cerebral cortex, hippocampus and thyroid gland in guinea pigs were quantitatively determined by flow cytometry and immunofluorescent techniques. RESULTS: The proportion of apoptosis in the cells of cerebral cortex, hippocampus and thyroid gland was significantly higher in the group with excessive iodine intake than that in the control one (P < 0.01). The level of expression of bcl-2 gene was notably decreased (P < 0.05), but that of bax was notably increased (P < 0.01), in the cerebral cortex, hippocampus and thyroid gland in the group with excessive iodine than in the control one. The ratio of bcl-2 to bax in the cerebral cortex, hippocampus and thyroid gland of the group with excessive iodine was decreased significantly (P < 0.01) than that of the control one. CONCLUSION: Excessive iodine intake may induce apoptosis in the cells of cerebral cortex, hippocampus and thyroid gland. The over-expression of bax gene and the down-regulation of bcl-2, which can then cause the decrease in a ratio of bcl-2 to bax, appear to play an important role in the course of apoptosis induced by excessive iodine intake.

Animals↗

PubMed2000

[Clinical analysis of 106 cases of inhalation injury induced by gas explosion].

OBJECTIVE: To review the management of inhalation injury induced by gas explosion in our department, so as to draw some experience and lessons for future work. METHODS: One hundred and six cases of inhalation injury induced by gas explosion were analyzed in terms of the characteristics of and therapeutic methods for the disease. RESULTS: The injury induced by gas explosion was very complicated with high incidences of compound injuries, severe inhalation injury and systemic infection. In addition, respiratory dysfunction occurred very quickly and severely at early postburn stage, which could easily develop to respiratory failure. The latter could ultimately lead patients to death due to improper management. CONCLUSION: In order to raise cure rate of the inhalation injury induced by gas explosion, airway obstruction should be cleared immediately and fiberbronchoscopy and respirator should be employed as soon as possible to help remove endotracheal obstruction and to maintain effective gas exchange. In addition, correct pulmonary resuscitation and continuous blood gas analysis were advocated.

Adolescent↗

PubMed2000

[Qualitative recognition on omitted ingredients in Liuwei Dihuang Pills by Bayesian analysis and PRIMA].

OBJECTIVE: To qualitatively recognize the omitted ingredients in Liuwei Dihuang Pills by Bayesian analysis and PRIMA. METHODS: The extracts of the pills were analyzed by HPLC, for each object, the areas of nine peaks relative to that of the internal standard were selected as classification features. The classification model was established on 169 training-set objects. RESULT: The classification average accuracy was 100% for four patterns by Bayesian analysis, and 99.6% by PRIMA analysis. CONCLUSION: Bayesian analysis and PRIMA analysis can be used to classify and recognize the omitted ingredients in Liuwei Dihuang Pills.

Bayes Theorem↗

PubMed2000

[The lymphocyte subset and blood interleukin-2 level in children with Henoch-Schönlein purpura before and after cimetidine treatment].

The objective of this study was to evaluate the effect of cimetidine treatment on cellular immunity in children with Henoch-Schönlein purpura. T cell subset was detected by double marker flow cytometry and the level of IL-2 in peripheral blood was measured by MTT method, before and after cimetidine treatment. The results showed that CD3+, CD4+ T cell subset, CD4+/CD8+ ratio, and blood IL-2 level increased after the treatment (P < 0.05). There was no significant change in CD8+ T subset after the treatment. These findings indicate that cimetidine can promote T lymphocyte proliferation and differentiation, especially TH1 lymphocyte activity.

Adjuvants, Immunologic↗

PubMed2000

[Computer-aided compose panoramic arthroscopic images of the temporomandibular joint].

OBJECTIVE: The computer-aided image processing method is established to compose arthroscopic images of temporomandibular joints(TMJs). METHODS: Arthroscopic images were input directly into a personal computer and recorded at a compact disk. By using the software- Photoshop 5.0 for Window 95, the images were edited and adjusted to form sagittal and/or coronal panoramic images of articular surfaces. RESULTS: The normal sagittal and coronal two-dimensional integrated panoramic arthroscopic images of TMJ were obtained, and qualities of these images were satisfied. CONCLUSION: The arthroscopic panoramic images established by using this method can demonstrate integrated structures of articular surfaces directly.

Arthroscopy↗

PubMed2000

[Clinical application of computed arthroscope of the temporomandibular joint].

OBJECTIVE: The effect of clinical application on the computed arthroscope of the temporomandibular joint (TMJ) is evaluated. METHODS: The single arthroscopic images were input into computer and memorized into magneto optical disk. With the help of Photoshop 5.0 in WINDOWS 95, the images were combined by technique of virtual process, adjusted by rotation of images, marginal blur, and chromatism correction to compound sagittal and/or coronal panoramic images of articular surfaces. According to different needs, the composite images can be printed with different printers. During the period from May 1998 to May 1999, the TMJ preoperative panoramic images were composed with computed arthroscope (CA) in the 32 joints. Of them, there were 12 joints with internal derangement (ID), 8 osteoarthrosis (OA), 8 adhesion, 2 disk perforation, and 2 synovial chondromatosis. The post-operative panoramic images were also made up to evaluate the surgical effects in 10 joints. RESULTS: In all of 32 joints, the 32 panoramic arthroscopic images of upper cavities were composed. In addition, the images of lower cavities were composed in 2 OA and 1 perforation. The postoperative panoramic images were also made up in 4 OA, 4 adhesion, and 2 synovial chondromatosis. All of the above-mentioned images showed integrally the entire structure of articular cavity, intracapsular pathologic/surgical appearances, and the relationships among the different tissues or articular surfaces. CONCLUSION: The CA can enhance the comprehensive ability of diagnostic arthroscope, and help to exchange and spread the experiences of the TMJ arthroscopic surgery.

Arthroscopy↗

PubMed2000

[Screening of acrystalliferous mutants from Bacillus thuringiensis and their transformation properties].

After elevating growth temperature of YBT-1463 and other 8 Bacillus thuringiensis parental strains to 42 degrees C, 9 acrystalliferous(Cry-) mutants were obtained, and then a series of partial plasmid-cured mutants were further obtained from 3 Cry- mutants BMB151, BMB154 and BMB160 by elevating temperature to 44 degrees C. One of which, BMB170, was further treated by elevating temperature to 46 degrees C and adding 0.05% SDS as the plasmid-curing agent. The resulting mutant, which was designated BMB171 and had no resident plasmid, was finally obtained. The studies on the transformation efficiency and stability of Cry- mutants showed that the transformation frequencies, as well as stability of several exogenous plasmids(pHT3101, pBMB1736, etc.) introduced into Cry- mutants by electroporation, were correlated with the numbers of resident plasmids bearing by the relevant recipients, the patterns of plasmid replicons and the sizes of those exogenous plasmids. Meanwhile, a much higher electro-transformation frequencies of Cry- mutants than the parental strain YBT-1463 was found, and the highest of the transformation frequency, in BMB 171, could reach up to 10(7) transformants/microgram DNA, and the stability of those exogenous plasmids in BMB171 were also higher than in other Cry- mutants and YBT-1463 strain.

Bacillus thuringiensis↗