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Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 955 records · Page 53Linked to original sources
PubMed2000

[Effects of somatostatin and its analogue on canine sphincter of Oddi motility].

OBJECTIVE: To investigate the effects of somatostatin and its synthetic analogue on canine sphincter of Oddi interdigestive motility. METHODS: Six dogs were used to establish the chronic manometry model to study the sphincter of Oddi motility, which were then classified into three groups: somatostatin, stilamin, and sandostatin groups. Each dog was studied weekly. The sphincter of Oddi manometry in fast and conscious state was undertaken with PC Polygraf HR before and after intravenous administration of agents to record the motility index (MI), basal pressure, and amplitude, duration and frequency of phasic contraction. RESULTS: Administration of somatostatin and stilamin of 0.5 nmol.kg(-1).h(-1) dose could induce phasic contraction of sphincter of Oddi and increase MI. The above two agents of 1 nmol.kg(-1).h(-1) dose could inhibit contractile activity of sphincter and decrease MI. Sandostatin of 0.5-1 nmol.kg(-1).h(-1) dose could induce phasic contraction of sphincter of Oddi; however, the agent of 0.5 nmol.kg(-1).h(-1) dose increased MI while 1 nmol.kg(-1).h(-1) dose had no effect on M. CONCLUSION: Effects of somatostatin and stilamin are biphasic in the regulation of sphincter of Oddi motility; small dose of the agents stimulates the sphincter motility while large dose inhibits the motility. Sandostatin regulates the sphincter of Oddi motility; the agent of small dose exerts excitatory role while large dose plays no significant role.

Animals↗
PubMed2000

[Study on the FcepsilonRI-beta polymorphism and susceptibility of asthma in a Chinese population].

OBJECTIVE: To investigate the linkage between the polymorphisms of FcepsilonRI-beta gene and susceptibility of asthma in a Chinese population. METHODS: Thirty-two families with 192 samples and 122 cases of childhood asthma were studied. A coding variant of E237G was detected by PCR/XmnI restriction endonuclease digestion. Two RsaI polymorphic sites within non-coding region were tested by PCR/RsaI restriction endonuclease digestion. RESULTS: The allele frequencies for all three polymorphisms of FcepsilonRI-beta gene in the Chinese population were markedly different from those published results of Caucasians and Japanese. Comparing asthma family samples with normal control, we found that genotypes containing A allele within intron 2 polymorphic site were associated with asthma (P < 0.05, OR = 2.039). The level of total serum IgE showed significant difference among three genotypes of intron 2 polymorphic site (P < 0.05). The association between A allele and elevated total serum IgE was also significant (P < 0.05, RR = 1.361). We could not find any significant results from the other two polymorphisms, even in the coding variant E237G. CONCLUSION: We were unable to confirm that the FcepsilonRI-beta gene was crucial to the susceptibility of asthma and atopy and did not contribute substantially to variation in IgE levels from both sample groups.

Adolescent↗
PubMed2000

[Regulating effects of transforming growth factor-beta (TGF-beta) on gene expression of collagen type II in human intervertebral discs].

OBJECTIVE: To assess the regulating effects of TGF-beta on gene expression of collagen type II in the human intervertebral discs. METHODS: In situ hybridization was used to investigate the effect of TGF-beta1 on collagen mRNA in confluent primary and passaged monolayer cell cultures of annulus fibrosus (AF) as well as nucleus pulposus (NP). The mean photodensitometry of cell smears as semi-quantitative analysis was evaluated by VIDAS software. RESULTS: In primary cultures, 1 ng/ml and 10 ng/ml TGF-beta1 inhibited the collagen type II mRNA levels by 74.6% and 60.2% respectively in AF; they also inhibited the mRNA levels by 69.6% and 55.5% respectively in NP. In passaged cultures in which the notochordal cells and chondrocytes were in dedifferentiation status, 1 ng/ml and 10 ng/ml TGF-beta1 increased the collagen type II mRNA levels by 151% and 166% respectively in AF and also increased the mRNA levels by 145% and 198% respectively in NP. CONCLUSIONS: The regulation effect of TGF-beta on collagen type II gene expression is dependent on whether the cells are fully differentiated or undergoing phenotype loss, and TGF-beta may play an important role in the repair process during early disc degeneration, especially in nucleus pulposus.

Cells, Cultured↗
PubMed2000

[Cataract extraction with rotated-chipping phacoemulsification in the capsule].

OBJECTIVE: To observe the clinical effects of rotated-chipping phacoemulsification in the capsule. METHODS: The operation of continuous circular capsulectomy, nuclear hydrodissection, cataract extraction with rotated-chipping phacoemulsification in capsule and intraocular lens implantation was performed on 215 eyes. RESULTS: Rotated-chipping technique was successfully completed in 215 eyes. In the operation 2 to 4 circles were rotated with the ultrasonic energy 19.3% for 12 seconds on average. The rate of corneal endothelium loss was 7.5%. CONCLUSION: The technique of rotated-chipping phacoemulsification in capsule is safe and rapid which can be used for cataracts with nuclei of various degrees in sclerosis.

Aged↗
PubMed2000

[Digital photography and blurred image processing of retinal nerve fiber layer in glaucoma].

OBJECTIVE: Red-free photographs are effective in detecting retinal nerve fiber layer (RNFL). The reasons why it is not used by most clinics are difficulty in laborious developing and blurred image evaluating. To account for getting real-time image and blurred image evaluating, the digital photography and computerized image processing are used. METHODS: RNFL photographs were taken by Nikon Fundus Camera connected with a high resolution digital camera (Kodak) and a green filter. As usual it is necessary to see the texture of RNFL in evaluating its image, but blurred images due to media opacities greatly lose their resolution. The way we used no focus on seeing the texture of RNFL, but on evaluating the distribution pattern of RNFL. RNFL images have more white reflex in temporal superior, temporal inferior, nasal superior and nasal inferior sections around optic disc according to the thickness of RNFL. Threshold segmentation was used, we shift a threshold bar to the position until the nasal or temporal section around optic disc is black with the software Photoshop. RESULTS: In the normal RNFL image, the white reflex was of butterfly pattern, i.e., the temporal superior and temporal inferior sections around optic disc were white. In cases with glaucoma, the characteristic of early damage of optic nerve was the loss of RNFL at the temporal superior and temporal inferior part of the retina, thus the normal butterfly pattern was changed, the temporal superior or/and temporal inferior sections were black. With this method it is more effective to evaluate RNFL. However, in cases with retinal pigment epithelium faint in color and in cases with choroidal defect, it is still difficult to evaluate the distribution of RNFL. CONCLUSIONS: It is an easy and effective way to detect glaucomatous damage with the digital photography and RNFL pattern evaluation.

Glaucoma↗
PubMed2000

[Selection of population-based controls in pair-matched case-control study analyzing risk factors for lung cancer].

OBJECTIVE: To explore the methods to select population-based controls in a pair-matched case-control study of risk factors for lung cancer and to lay foundation for development of their monitoring in urban areas. METHODS: Data of cases of lung cancer and their three different groups of pair-matched control based on population from the "Study on surveillance for incidence and mortality of common malignant tumor and their risk factors" in Beijing, Tianjin, Shanghai and Chongqing were personally-interviewed and analyzed with conditional multivariate logistic regression using STATA software involving 1 312 pairs aged 35 - 74. RESULTS: Odds ratios for main risk factors were consistent with the three groups of controls, and there was certain difference in ORs for dietary factor, etc. between the studies with three difference control groups. There was little differences in frequencies of exposure to risk factors between studies with neighbor-controls and normal-controls. Cigarette smoking, lower body mass index, long-time depressed mood, lower capability of emotion regulation, previous respiratory diseases, family history of cancer in the first-degree relatives significantly increased the risk for lung cancer after adjusted for age, education level, family average income and other risk factors. CONCLUSION: It was feasible to use population-based controls instead of neighbor controls in surveillance for risk factors of lung cancer.

Adult↗
PubMed2000

[A case-control study of the risk factors of lung cancer in Beijing, Tianjin, Shanghai, Chongqing metropolitan areas].

OBJECTIVE: To analysis the risk factors of lung cancer and determine the surveillance index in urban areas in four metropolises in China. METHODS: The paper used the data from the in-person interviews of National Research on Malignant Tumor Morbidity, Mortality and Surveillance Methods in 1996. We carried out a 1:1 matched case-control study based on population involving 1 312 cases and 1 312 neighborhood controls aged 35 - 74 from Beijing, Tianjin, Shanghai, Chongqing urban areas. The relationships between risk factors and lung cancer were analyzed by conditional univariant and multivariate logistic regression on the computer package, STATA. RESULTS: Cigarette smoking, lower body mass index, longtime depressed mood, lower capability of emotion regulation, previous respiratory diseases, family history of cancer in first-degree relatives significantly increased the risk of lung cancer after adjusted by age, education, family average income and other risk factors. The odds ratios of these risk factors were 3.46 (95% CI 2.70 - 4.45), 1.18 (95% CI 1.22 - 1.40), 2.64 (95% CI 1.95 - 3.57), 2.71 (95% CI 2.02 - 3.65), 2.28 (95% CI 1.81 - 2.88), 1.79 (95% CI 1.38 - 2.32), respectively. The odds ratio associated with the highest quartile of fresh vegetables consumption compared with the lowest was 0.75 (95% CI 0.65 - 0.87), showed an inverse relationship. Exercising more often had a significant inverse association between cases and controls, and its odds ratio was 0.81 (95% CI 0.74 - 0.89). CONCLUSION: Cigarette smoking, psychological factor, previous respiratory diseases and family history of cancer were the main risk factors of lung cancer in four cities. They were the important surveillance index of lung cancer. The relation between lung cancer and environmental tobacco smoke, dietary factors and the factors related with female etc. should conduct further studies or special studies which defined the exposures carefully and exactly.

Aged↗
PubMed2000

[The changes in serum antibody level after immunization with HFRS vaccine].

OBJECTIVES: To observe the changes in serum antibody level after mass immunization with vaccine against hemorrhagic fever with renal syndrome (HFRS) and to evaluate its efficacy and effectiveness in the prevalent areas. METHODS: Healthy people aged 16 to 60 years in the villages were recruited as study subjects, excluding those suffered from HFRS previously, going out for more than nine months and those with contraindications, and were randomly allocated into immunization and control groups with 10,460 and 16,159 persons, respectively. Specific IgG antibody was determined with indirect immunofluorescent assay (IFA) and neutralizing antibody (NA) was determined with micro CPE method. RESULTS: Two weeks after the full-course immunization, sero-conversion rate for IFA reached 100% in those sero-negative before immunization, with a 95% confidence interval of 96.3 - 100.0%, and that for NA 44.4%, with a 95% CI of 22.0% - 69.0%. Geometric mean titer (GMT) were 72.1 and 4.6 for IFA and NA, respectively. Booster immunization was provided for them one year later. Positivity of IFA and NA was 28.6%, 83.3%, 75.0%, 53.1%, 22.6% and 14.8%, 55.6%, 35.0%, 31.3%, 26.0%, before booster immunization, two weeks, one year, one and a half years, two years after booster immunization, respectively. CONCLUSION: HFRS vaccine had good immunogenicity, but its duration of serum antibody sustenance was relatively short.

Adolescent↗
PubMed2000

[The effect of nordihydroguaiaretic acid on endothelial cell migration induced by glioma cells].

OBJECTIVE: To investigate the effect of nordihydroguaiaretic acid (NDGA) on the migration of endothelial cells (ECs) induced by glioma cells (GCs) in vitro. METHODS: Cells of human umbilical vein endothelial cell line ECV-304 and human malignant glioma cell line SHG-44 were co-cultured in the Falcon Cell Culture Insert system, and the effect of NDGA on the migration of ECs induced by GCs was investigated. The expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) was examined with immunohistochemistry. RESULTS: The expressions of VEGF and bFGF in SHG-44 cells were reduced after treatment with 100 micromol/L NDGA for 1 to 3 days. 100 micromol/L NDGA significantly inhibited not only the chemotactic migration of ECs induced by either glioma cells or glioma-conditioned media, but also the random motility of ECs (P < 0.01). NDGA at a concentration between 50 micromol/L and 200 micromol/L inhibited the chemotactic migration of ECs in a dose-dependent manner (the inhibition ratios were 12.0%, 37.4%, 86.7% and 82.2%). CONCLUSION: The results confirm the inhibitory effects of NDGA on the migration and angiogenic factor expression of ECs, which suggests that NDGA may suppress angiogenesis of glioma.

Brain Neoplasms↗
PubMed2000

[Study on the needle biopsies of 100 prostatic adenocarcinoma].

OBJECTIVE: To study the morphological diagnostic criteria of prostatic adenocarcinoma in needle biopsy. METHODS: 250 cases of prostatic needle biopsy including 100 cases of adenocarcinoma were observed retrospectively. The diagnostic significance of 20 parameters of morphological criteria including the architectural changes, cytologic features, invasion and some additional histologic features (intraepithelial neoplasm, intraluminal crystelloid body, intraluminal basophilic mucin secretion, collagen nodule and coagulative necrosis) were analyzed. RESULTS: All 20 parameters of morphological criteria had practical significance in pathologic diagnosis, the most significant ones being architectural changes, prominent nucleoli, perineural and stromal invasion. CONCLUSION: The diagnosis of prostatic adenocarcinoma is based on a constellation of cytologic and architectural features.

Adenocarcinoma↗
PubMed2000

[The effect of burn sera on the calcium homeostasis in isolated rat myocardial cells].

OBJECTIVE: To study the effect of burn sera on the calcium homeostasis in isolated rat myocardial cells. METHODS: The burn sera were obtained from the Sprague -- Dawley (SD) rats inflicted by 30% TBSA III degree burn at 2, 4 and 6 postburn hours with the harvesting of burn sera at different postburn times, named as 2 hBS, 4hBS and 6 hBS, respectively. Myocardial cells were isolated by enzyme digestion with retrograde perfusion apparatus. [Ca(2+)]i was detected with the fluorescent dye Fura -- 2 and L -- type calcium (ICa -- L) currents were recorded in the whole -- cell patch -- clamp model. RESULTS: Myocardial cellular [Ca(2+)]i became much higher in concent after being in cubated with sera, especially with 6hBS, than that in normal myocardial cells (P < 0.01). But the effect of 6hBS could be significantly inhibited by verapamil (30 nmol/L), the calcium channel antagonist and procaine (2 mmol/L), the inhibitor of rynodine receptor (P < 0.01) by 47.7% and 67.6%, respectively. Ca -- L was evidently increased by the stimulation of 2 hBS and 6 hBS, by 50 -- 80% and 1.5 -- 2.5 folds, respectively. It was indicated by I -- V curves that every ICa caused by depolarizaton and clamp voltage was increased by burn sera, which further made the maximal activating voltage ahead of time. All the burn sera effects on calcium current could be removed by extracellular lavage. CONCLUSION: The myocardial [Ca(2+)]i and ICa -- L could increase significantly when affected by burn sera. The alteration in calcium homeostasis might be a cellular mechanism of myocardial injury.

Animals↗
PubMed2000

[Alterations of anabolism in hepatic cells of burned rats measured by (13)C NMR spectroscopy].

OBJECTIVE: To introduce a safe and specific approach of (13)C NMR spectroscopy and investigate the alterations in hepatic anabolism functions including pyruvate recycling, gluconeogenesis and anaplerosis in severely burned rats. METHODS: Adult Spreque -- Dawley (SD) rats were catheterized arteriovenously via left carotid and right external jugular vein under inhalation anesthesia and were randomly divided into burn group (B) and sham burn group (S). Fluid resuscitation started 20 min postburn. Sodium [1, 2, 3 -- (13)C] propionate (SP) was intravenously administered as a tracer at 72 postburn hour (PBH). (13)C NMR spectroscopy of extracted plasma and liver, arterial blood pressure, heart rate and plasma glucose and sodium levels were measured. Metabolic parameters were calculated using a mathematical model of input -- output matrix to feed the tricarboxylic acid cycle. RESULTS: When compared to those in C group, burned rats exhibited a lower arterial blood pressure, but normal blood glucose at 72 PBH. Intravenous SP infusion did not alter MAP, heart rate and plasma sodium. The form of blood sugar labeled by (13)C isotopomer was in excellent agreement with that from liver. After continuous infusion of SP for 45 mins, SP could reach metabolic steady status. The hepatic cellular gluconeogenesis, anaplerosis and the carbon flow rate in pyruvate recycling significantly increased in B group when comparing to those in C group. But the carbon flow rate in Kreb's cycle decreased relatively, and hepatic pools of alanine, glutamic acid and glutamine were enlarged obviously in burned rats relative to sham burn group. CONCLUSION: These data suggested that intravenous infusion of SP would not alter MAP, heart rate and blood sodium. Forty -- five mins after the intravenous infusion, the tracer could reach metabolic steady status. The form of blood sugar labeled by (13)C could represent that of hepatic sugar. Seventy -- two hours after major burns, there were increased hepatic anaplerosis, gluconeogenesis and pyruvate recycling and a correspondent increased utilization ratio of blood sugar by peripheral tissue.

Animals↗
PubMed2000

[The effects of the receptor antagonist of glutamic acid on the brain tissue of severely scalded rats].

OBJECTIVE: To explore the influence of glutamic acid on burned rat brain tissue and the effects of the receptor antagonist of glutamic acid. METHODS: Rats inflicted with 30% TBSA III degree scalding injury were taken as the model. The water content, K(+), Na(+), Ca(2+), Mg(2+), nitric oxide metabolites (NO(2)(-)/NO(3)(minus sign))concentrations of scalded rat brain were determined at 2, 6, 12 and 24 postburn hours (PBH). Morphological and histochemical studies of the brain tissue were carried out with LM and EM. RESULTS: The water content, Na(+), Ca(2+)and NO(2)(minus sign)/NO(3)(minus sign) concentrations of the brain tissue after scalding injury were higher than those in control group. But intracerebral ATP enzyme decreased postburn. It was found by EM examination that there existed swelling of capillary endothelium, nerve cells and some intracytoplasmic mitochondria. There appeared pinosome on capillary wall. After the administration of receptor antagonist of glutamic acid, D-2-amino-group-7-phosphoenanthate (D-AP7), the brain water content, Na(+), Ca(2+)and NO(2)(-)/NO(3)(-) concentrations in brain tissue, and the capillary wall pinosome decreased, and the swelling of nerve cells ameliorated. CONCLUSION: There might be postburn increased cerebral microvascular permeability, ischemic injury of cerebral tissue cells and the development of brain edema. The postburn alterations in the morphology and metabolism of brain tissue were correlated with the over secretion of glutamic acid. And the excitatory toxic effects of glutamic acid were mediated by its receptor. The receptor antagonist of glutamic acid D-AP7 might ameliorate postburn cerebral injury.

Adenosine Triphosphatases↗
PubMed2000

[Antiphospholipid thrombosis syndrome and acquired activated protein C resistance].

OBJECTIVE: To explore the correlation between antiphospholipid antibodies (APA) activated protein C resistance (APCR) and antiphospholipid thrombosis (APL-T) syndrome and investigate the mechanism of thrombosis in APL-T syndrome. METHODS: ELISA, APTT-LA and APTT+/-APC methods were used to detect anticardiolipin antibodies (ACA), lupus anticoagulants (LA) and APCR in 20 APL-T syndrome patients respectively. RESULTS: Twenty patients were diagnosed as APL-T. The patients were classified in three ways. According to etiology, 14 of 100 systemic lupus erythematosus (SLE) patients were diagnosed as "secondary" APL-T, and 6 of 16 "unexplained" thrombosis and spontaneous abortion as "Primary" APL-T syndrome. According to antibodies, 12 of 20 patients with positive LA were diagnosed as lupus anticoagulant thrombosis syndrome (LA-T), 12 of 20 patients with positive ACA as anticardiolipin antibodies thrombosis syndrome (ACA-T). According to clinical presentation: 7 of 20 patients with deep vein thrombosis were classified as type I APL-T, 3 of 20 patients with cerebrovascular thrombosis as type II, 1 of 20 patients with vein cerebrovascular thrombosis and spontaneous abortion as type IV (mixing), and 9 of 20 patients with spontaneous abortion as type V (fetal wastage type). The ACAs and LA are strongly associated with APL-T. There is close relationship between APCR and APL-T. CONCLUSION: The acquired APCR might be an important reason for thrombosis in APL-T caused by APA and LA.

Activated Protein C Resistance↗
PubMed2000

[Study on the clinical characteristics of biphenotypic acute leukemia].

OBJECTIVE: To analyze the biological characteristics and the treatment outcome of adult biphenotypic acute leukemia. METHODS: Immunophenotypes were examined using indirect immunofluorescence method. Biphenotypic acute leukemia (BAL) was diagnosed according to EGIL scoring system. RESULTS: (1) The incidence of BAL in acute leukemia was 3.4%. Percentage for coexpression of B lymphoid and myeloid antigens was 68.4%, for T lymphoid and myeloid antigens 21.1%, for B, T lymphoid and myeloid antigens 10.5%. (2) CD(34) was expressed in 43.75% of the BAL cases. (3) Cytogenetic analysis revealed normal and abnormal karyotypes in 41.7% and 58.3% of the BAL cases, respectively. (4) Six of 19 patients achieved completed remission (CR), but the disease free survivals were all less than 6 months. Treatment outcomes were negatively related to the expression of CD(34) antigen and cytogenetic findings. The BAL patients were poorly responded to therapeutic regimens directed to AML. CONCLUSION: Coexpression of B/M antigens is the commonest subtype in BAL. BAL had a poor prognosis, especially treated with induction regimen directed to AML.

Acute Disease↗
PubMed2000

[Changes of glucocorticoid receptor in cerebral and hepatic cytosol during decompression stress injury in rats].

Objective. To observe the changes of glucocorticoid receptor (GR) in cerebral and hepatic cytosol during decompression stress injury in rats. Method. 30 rats were divided into 5 group. They were placed into the compression chamber for compression and decompression. The binding capacity of GR of cerebral and hepatic cytosol were measured by the exchange assay, using 3H dexamethasone as the ligand. Meanwhile, decompression bubbles on pericardial area were measured using Doppler ultrasonic method. Result. The binding capacity of GR of cerebral and hepatic cytosol reduced after decompression stress injury in the animals, especially cerebral cytosol (P<0.01, P<0.05). The result also showed that the binding capacity of cerebral and hepatic GR should have further decreased, if the therapeutic measure had not been used in animals suffered from decompression sickness (DCS). Conclusion. The changes of the binding capacity of GR of cerebral and hepatic cytosol were proved to be related to decompression stress injury, which might be taken as one of the indices for evaluating injury degree of DCS.

Animals↗
PubMed2000

[Studies on chemical constituents of processed green tangerine peel].

OBJECTIVE: To study the chemical constituents of processed green tangerine peel(Citrus reticulata). METHOD: Using chemical techniques and spectroscopic analysis. RESULT: Four compounds were isolated from the peel and identified as hesperidin, neohesperidin, nobiletin and tangeritin. CONCLUSION: The compounds were obtained from this peel for the first time.

Acetic Acid↗