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Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 1,207 records · Page 67Linked to original sources
PubMed1999

[The influences of genetic and environmental factors on plasma plasminogen activator inhibitor-1 levels in patients with essential hypertension].

OBJECTIVE: To investigate the influence of a 4G/5G polymorphism in the PAI-1 gene promoter and environmental factors on plasma plasminogen activator inhibitor-1(PAI-1) levels in subjects with essential hypertension. METHODS: A total of 240 patients with essential hypertension(males 120, females 120, aged 33-89 years, mean 65 years) were randomly enrolled in this study. Plasma PAI-1 antigen was measured by ELISA. The 4G/5G polymorphism was analyzed by the allele specific oligonucleotide hybridization method. RESULTS: Plasma PAI-1 levels were significantly associated with 4G/5G polymorphism with the highest levels occurring in subjects with 4G/4G genotype, the intermediate levels in 4G/5G subjects and the lowest levels in 5G/5G subjects. 4G/5G polymorphism, diabetes mellitus and triglyceride(TG) were three independent predictors of plasma PAI-1 levels in a stepwise multiple regression model. Furthermore, the relationship between plasma PAI-1 levels and TG was genotype dependent. CONCLUSION: Plasma PAI-1 levels are not only under genetic control, but also influenced by several environmental factors. There is an interaction between genetic and environmental factors.

Adult↗
PubMed1999

[Mitochondrial DNA genetic polymorphism of Drosophila immigrans in China].

This article uses RFLP to analyze the mitochondrial DNA(mtDNA) variation in geographic populations of Drosophila immigrans from 6 regions of mainland of China. With the use of fourteen restriction endonucleases, we only discoveried a total of 11 mtDNA haplotypes among 46 isofemale lines. The mean value of I is 0.833, the mean value of J is 0.797, and the estimated Gst value is only 16.8%. We recognized that the genetic structures among the geographic populations of D. immigrans are highly uniform, and the genetic differentiation rate is low. The UPGMA analysis of nucleotide diversity of the 6 populations shows specific characteristics of mtDNA variation in population of Huayang, Qinling Mountains Regions. From the haplotypes special included in each population, the event that the population spread into the high altitute localities of Yunnan perhaps happened more recently. Referring other references, we inferred the population of D. immigrans distributed in mainland of China is more original than that in Chinese Taiwan and Japan.

Animals↗
PubMed1999

B7-1 antigen expression in tumor cells from cancerous human tissues.

OBJECTIVE: To explore the expression of B7-1 antigen (Ag), the most important costimulatory molecule for T-lymphocyte activation, on tumor cells from cancerous human tissues. STUDY DESIGN: The study group consisted of 82 biopsies taken from a variety of cancerous human tissues. Ten normal cervical specimens, used as controls, were taken from uteri removed for leiomyomas or leiomyomatosis. B7-1 molecule expression was identified using monoclonal antibody (Ab) with CD80 and the SABC technique. RESULTS: In most cases (50/82), the tumor cells were totally or partially B7-1 Ag positive. The positive products were distributed mainly on the cell surface and, in some cases, also in the cytoplasm. Although in transitional cell carcinoma of the bladder, all tumor cells in all three cases stained strongly with CD80, in squamous cell carcinoma and adnocarcinoma, the B7-1 expression in cancer cells was detected in 3/56 and 15/23 cases, respectively. The intensity and distribution of B7-1 expression from case to case were heterogeneous: half the cases had relatively homogeneous and stronger B7-1 expression in cancer cells. Additionally, there were B7-1+ dendritic cells and lymphocytes scattered or densely infiltrating interstitial tissue. In some cases, the endothelia of small vessels were proved to be B7-1+. There was one esophageal cancer specimen containing normal-looking mucosa in which B7-1 molecule expression was also demonstrated in the squamous and glandular epithelia. CONCLUSION: Our findings demonstrate that the tumor cells in cancerous human tissues do not all fail to express B7-1. The mechanism of the failure of hosts to reject tumors can be attributed not only to the lack of costimulatory molecules in tumor cells but also to events after the Ag-presenting process.

Adenocarcinoma↗
PubMed1999

[Logistic regression analysis of female drug abusers' social-psychological factors].

OBJECTIVE: To study the social-psychological health status on female drug abusers. METHODS: Case-control study and logistic regression analysis. RESULTS: Results of simple logistic regression showed that factors with significant ORs were low education level, unemployment, marital status, senseless of life, self-killing, horror, madness, depression, insomnia, dizziness, perspiration, evil dream, divorce, setbacks of emotion, smoking, alcohol-abuse, playing truant, runaway from home, fighting, etc. The results of stepwise logistic regression analysis showed that factors entered the regression model were smoking, runaway from home, divorce, setbacks of emotion, marital status, hopeless toward life, level of education, dizziness, etc. CONCLUSION: Most female drug abusers' social-psychological status was poorer than controls preceding to their drug abuse, which contributed to the major causes of abuse drugs.

Adolescent↗
PubMed1999

[Study on esophageal motility and its effect by EVL in patients with esophageal varices].

OBJECTIVE: To investigate the esophageal motility and its effect by EVL in patients with cirrhotic esophageal varices. METHODS: LESP, LESR, PA, PD, PV and 24 h pH-monitoring were measured by PC Polygraf HR system in subjects of control and cases of esophageal varices before and after EVL. RESULTS: In varices group, PA, PD, and PV were significantly abnormal in comparison with those in control group (P < 0.001, 0.01, 0.01). There were pathologic acid-reflux in patients with esophageal varices. After EVL, PA, PV and acid-reflux were significantly recovered. CONCLUSION: Patients with esophageal varices suffer from the significant abnormal esophageal motility and acid-reflux. All of the abnormal changes can be recovered by EVL treatment.

Adult↗
PubMed1999

Standard growth curve chart for body height of Chinese adolescent for orthodontic diagnosis.

OBJECTIVE: To make a standard growth curve chart on the body height of Chinese adolescents. METHODS: Statistical data from 32,524 Sichuan students aged 7 to 19 years were surveyed in 1995. Mean values of the annual increment of body height and the ages of the pubertal growth periods were analyzed. RESULTS: During the period between 9 and 13 years of age, females grow faster than their male peers. After age 13 years, males surpass females, and the difference in physical growth and development becomes more pronounced. CONCLUSIONS: The new standard growth curve chart on the body height of Chinese adolescent may be applied to better understand the growth pattern of Chinese orthodontic patients.

Adolescent↗
PubMed1999

Studies on biosensor to determine diacetyl.

We studied the purification of diacetyl reductase, the preparation of a biosensor, and its performance. With diacetyl reductase and reduced coenzyme I (NADH) co-immobilized as working membrane, NAD+/NADH produced in the course of diacetyl reduction was connected with Fe2+/Fe to build a biosensor. The biosensor could be used to determine diacetyl concentration within the range from 0.1 microgram/mL to 0.5 microgram/mL and the response time was less than two minutes, and its performance was stable within 9 days. The experiments showed that typical metal ions and organics in nominal concentration did not affect the performance of the biosensor, meanwhile, the interference of dissolved oxygen on the performance of biosensor and regeneration of coenzyme I (NADH) were solved to some extent.

Acetoin Dehydrogenase↗
PubMed1999

[The relation between placental pathologic changes and serum nitric oxide levels of maternal and umbilical blood in intrauterine growth retardation].

OBJECTIVE: To study the relation between placental pathologic changes and levels of maternal and umbilical serum nitric oxide (NO) in intrauterine growth retardation (IUGR). METHODS: 38 patients with IUGR (IUGR group) and 30 healthy pregnant women in their late trimester (control group) were studied from Nov. 1997 to Oct. 1998. The placenta and the appendages of fetus were studied after delivery. The concentration of serum NO were determined with cortas' method. RESULTS: Placental pathological changes were found in 26 cases of IUGR group (68.42%), and the main pathological changes were growth retardation of villi and villositis. In the control group, 5 out of 30 cases had placental pathological findings (16.67%). There was statistically significant difference between the 2 groups (P < 0.01). In IUGR group, the maternal and umbilical NO concentration in the 26 cases with placental pathological changes decreased significantly when compared with that in 12 cases without obvious pathological findings of placenta (P < 0.05, P < 0.05); NO levels of umbilical cord were higher than that of maternal serum in both groups(P < 0.01, P < 0.05); There was correlation about serum NO concentration between mother and her fetus in both groups (r = 0.5475, r = 0.8506); but umbilical serum NO level was not related to the weight of the newborn (r = 0.2838). CONCLUSION: The obvious placental pathologic changes occurred in patient with IUGR caused noticeably lower NO levels in maternal and umbilical serum.

Adult↗
PubMed1999

[A study on the role of contractile and relaxant reaction of umbilical vein in vitro and local changes of nitrix oxide synthase in the pathogenesis of pregnancy induced hypertension].

OBJECTIVE: To study the contractile and relaxant reaction of human umbilical veins in vitro from pregnancy induced hypertension (PIH) patients, pathophysiological significance and the role of local changes of nitric oxide synthase (NOS) in the pathogenesis of PIH. METHODS: The contractile and relaxant curves of umbilical vein in response to phenylephrine, isoprenaline and acetylcholine were recorded in the PIH group and normal pregnancy group (control group). The maximum effect (Emax) and affinity index (pD2) volume were calculated. Meanwhile, the NOS activity in the blood vessel tissue and the plasma concentration of nitric oxide metabolite (NO2-/NO3-) were examined. RESULTS: (1) Relaxtant of the Emax of umbilical vein in the control group in response to acetylcholine was (85.0 +/- 15.0)%, pD2 volume was 4.4 +/- 0.5; However, the Emax (70.0 +/- 13.0)% and the pD2 (3.7 +/- 0.6) were significantly lower in the PIH group (P < 0.01). No significant differences of Emax and pD2 were obtained in phenylephrine-induced vessel contraction and isoprenaline-induced relaxation between the groups (P > 0.05). (2) NOS activity of umbilicahich was significantly lower than that from the control group [(0.5 +/- 0.2) nmol.g-1.min-1] (P < 0.01). The plasma NO2-/NO3- concentration was (38.0 +/- 10.0) mumol/L in the PIH group, which was also lower than that in the control group [(56.0 +/- 14.0) mumol/L] (P < 0.01). CONCLUSIONS: The abnormal function of endothelium system and abnormal metabolism of nitric oxide in blood vessel, which resulted in the decreased endothelium dependent relaxation, might be possible mechanism involved in the pathogenesis of PIH.

Adult↗
PubMed1999

[Expression of focal adhesion kinase in lymphatic endothelial cells of metastasis].

This study was directed at the expression of focal adhesion kinase (pp125FAK) which is located together with vinculin and talin in the spot of cellular adhesion. The authors' intention was to collect reliable data on this important kinase in the signal pathways so as to provide in-depth materials for exploring the mechanism of tumor metastasis to lymphatic vessels. The immunohistochemical method was used to study the expression of FAK in lymphatic endothelial cells of metastaltci adenocarcinoma of rectum and its adjacent lymph-nodes. The result demonstrated that lymphatic endothelial cells expressed pp125FAK when lymphatic vessels were invaded by cancer cells. Reaction production was located in the cytoplasm. This study provides that there was a strong correlation between the expression of FAK in lymphatic endothelial cells and the metastasis of cancer to lymphatic vessels.

Adenocarcinoma↗
PubMed1999

[Study on in vitro cytokines levels induced from peripheral mononuclear cells in patients with endometriosis].

OBJECTIVE: To study the changes and significance of interleukin-6 (IL-6), interleukin-8(IL-8), tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) levels in vitro cultured system of peripheral mononuclear cells in patient with endometriosis(Em). METHODS: Peripheral blood mononuclear cells from 31 cases of endometriosis, classified into mild group (stage I and II, n = 11), and severe group (stage III and IV, n = 20) according to the Revised American Fertility society criteria 1985, and 15 normal controls were separated and induced by lipopolysaccharide and phytohemagglutinin, followed by 48 hour incubation in vitro, then the supernatant were collected. The levels of IL-6, IL-8 and TNF-alpha were measured by enzyme linked immunosorbent assays, the concentrations of NO, expressed by nitrite and nitrate (NO2-/NO3-) content were measured by Griess methods. RESULTS: The concentrations of IL-6, IL-8, TNF-alpha and NO were significantly higher in both mild and severe Em groups than those in controls (P < 0.01). No differences between the mild and severe Em groups was seen. There were strong positive correlation between the levels of IL-6 and IL-8, TNF-alpha and NO in patients with endometriosis (P < 0.01). CONCLUSIONS: The immune function of peripheral mononuclear cell in patients with endometriosis was disordered. It may activate peripheral mononuclear cells to produce high levels of IL-6, IL-8, TNF-alpha and NO, which may take part in the pathogenesis of endometriosis.

Endometriosis↗
PubMed1999

[Expression of apoptosis regulatory protein bcl-2 and bax in endometrium of polycystic ovary syndrome].

OBJECTIVE: To study the expression and implication of apoptosis regulatory protein bcl-2 and bax in endometrium of polycystic ovary syndrome (PCOS). METHODS: The apoptosis regulatory protein expression of bcl-2 and bax protein in endometrium were investigated by immunohistochemical method in 18 PCOS and 27 normal subjects proliferative phase 10 and secretory phase 17. RESULTS: Bcl-2 expression was higher in PCOS than that both in control proliferative phase (P < 0.05) and secretory phase (P < 0.001). Bax expression was not significantly different between PCOS and controls (P > 0.05). CONCLUSIONS: The higher bcl-2 protein expression inhibits the endometrium apoptosis and plays an important role in the abnormal proliferative changes of endometrium in PCOS.

Adult↗
PubMed1999

Structural chemistry and biological activities of natural products from Chinese herbal medicines.

This is a brief account of recent developments (1978-1994) in natural product chemistry and bioactivity related to Chinese herbal medicine. In the period covered, more than thousand chemically new constituents were isolated and their structures elucidated. We have presented most of the structural formulae for the sake of clarity, along with passing mentions of pertinent biological activities. The isolates were grouped under different headings according to structure types.

Animals↗
PubMed1999

[The role and significance of PAF in the early pulmonary injury following burns combined with endotoxemia in rats].

OBJECTIVE: To investigate the role and significance of PAF in the early pulmonary injury following burns combined with endotoxemia in rats. METHODS: An animal model, in which rats were subjected to 20% TBSA III degree burns combined with intraperitoneal injection of lipopolysaccharide (LPS), was used for this experiment. The changes in the pulmonary morphology were observed by LM, EM and immunohistochemistry(IHC). The contents of PAF and TNF-alpha in the plasma were determined with quantitative analysis. PAF receptor antagonist(BN50739) was used to treat early pulmonary injury. RESULTS: PAF was one of the inflammatory mediators to precede TNF changes during burns combined with endotoxemia in the early stage of pulmonary injury. The contents of PAF in the plasma was positively correlated to the extent of pulmonary injury, which may be alleviated after injection of PAF receptor antagonist (BN50739). CONCLUSION: The results suggest that PAF plays an very important pathogenic role in the early lung injury resulted from burns combined with endotoxemia.

Animals↗
PubMed1999

[Repair of skin defects of the hand with the reverse forearm fasciocutaneous flap on the terminal radial artery].

OBJECTIVE: A large reverse forearm fasciocutaneous flap has been developed and used to repair defects of the hand. METHODS: Supplied by the terminal branches of the radial artery, the reverse forearm fasciocutaneous flap was designed as large as 3-5 cm above the elbow with its pedicle located 3-5 cm proximal to the radial styloid process. The flap can cover a large skin defect of the palm and back of the hand. RESULTS: We have successfully treated 42 cases of hand skin defects with the terminal radial artery reverse forearm fasciocutaneous flap. Postoperative follow-up in 18 cases revealed satisfactory results cosmetically and functionally. CONCLUSION: The terminal radial artery reverse fasciocutaneous flap is a simple, safe and less traumatic method for treatment of hand skin defects.

Adolescent↗
PubMed1999

[Early cardiac myocyte membrane changes in severely burned rats: a spin labding-ESR study].

OBJECTIVE: To demonstrate the mechanism of early cardiac myocyte membrane damage at molecular level in severely burned rats. METHODS: SD rats were randomly divided into sham-burn and burn groups. A 30% TBSA burn was created in burn group. Hearts were obtained at different time postburn. Cardiac myocytes isolated by collagenase using Langendoff perfusion apparatus were spin labeled with 5-doxylstearic acid (5NS), 16-doxylstearic acid (16NS) and 3-maleidoproxyl (3MP). The order parameters (S value), hs/hw ratio and rotational correlation time (tau c) were measured according to the spin labeling-ESR spectra. RESULTS: The S value of the polar head-group region of membrane lipid, as reported by 5NS, did not changed significantly, while that of the lipid in the hydrophobic midzone, as reported by 16NS, increased significantly. The hs/hw ratio of 2 and 6 hours postburn groups increased significantly postburn compared with that of the sham-burn group, and so did the rotational correlation time in 1 to 12 h postburn groups. CONCLUSION: There were structural and functional changes in cardiac myocyte membrane after burn injury. They were characterized by decreased fluidity in the deeper part of membrane lipid, configurational changes and motion restriction in membrane proteins. They could affect the normal performance of cardiac function.

Animals↗