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Biomedical subjects

M Chen

Publications and source records attributed to M Chen.

At least 343 records · Page 19Linked to original sources
PubMed1999

[Expression of adhesion molecules beta 1 integrin on the surface of fibroblasts in wound healing].

OBJECTIVE: To investigate the relationship between the expression of adhesion molecules integrin beta 1 and the synthesis of collagen in wound healing. METHODS: In this study, integrin beta 1 expression on fibroblasts derived from granulated wound and from normal skin was compared by the technique of immunoelectron microscope and flow cytometry. The differences of ultrastructure between the two groups of fibroblasts were also observed. RESULTS: The results showed that the expression of alpha 5 and beta 1 subunits on fibroblasts derived from granulated wound were higher than those from normal skin. Endoplasmic reticulum attached with more ribosome in the former cells was richer than that in the latter cells. CONCLUSION: These results suggest that the expression of adhesion molecules integrin beta 1 appears to be associated with the synthesis of collagen in wound healing.

Adolescent↗
PubMed1999

[The study and application of the alar cartilage ring in the treatment of deformities of unilateral cleft lip nose].

OBJECTIVE: To explore the possible pathogenesis and to look for effective reconstructive procedures of unilateral cleft lip nose. METHODS: The author has had a detailed comparative study by comparing the cartilaginous skeleton of 20 normal cadaver specimens with that of one unilateral cleft lip stillborn, as well as intraoperative findings of 24 clinical patients. RESULTS: There are two alar cartilaginous rings, namely alar cartilaginous fibrous ring and alar cartilaginous muscular ring, in external nose. Both rings are hypoplastic in the cleft lip patients. According to the findings, the author designed and applied a new operation procedure to reconstruct alar cartilage ring for 24 patients from 1994 to 1997. An acceptable short-term results were found. CONCLUSION: Alar cartilaginous fibrous ring and alar cartilaginous muscular ring are very important anatomic structures to maintain the shape of the lower part of the nose. Hypoplasia of these rings is an important factor leading to deformities of the nose. It is very important to reconstruct alar cartilage ring for the patients with unilateral cleft lip nose.

Abnormalities, Multiple↗
PubMed1999

[Antimicrobial resistance in Streptococcus pneumoniae in Beijing and molecular typing of penicillin-resistant strains].

OBJECTIVE: To investigate antimicrobial resistance of Streptococcus pneumoniae in Beijing and molecular epidemiology of penicillin-resistant pneumococci strains. METHODS: The resistance to beta-lactam and non-beta-lactam antibiotics of 244 nasopharyngeal isolates of Streptococcus pneumoniae collected from September to November 1997 in 8 day-care centers in Beijing was studied by Etest and agar dilution method. Serotyping was done by "capsular swelling" technique. BOX-PCR technique was used to detect the DNA of resistant strains. RESULTS: 24.8% (244/985) of the children carried Streptococcus pneumoniae. The agreement between the MICs obtained by Etest and agar dilution for penicillin and ceftriaxone was > 93.7%. By Etest, 3/244 (1.3%) strains were resistant to penicillin(MICs, 3 micrograms/ml) and 32/244(13.1%) strains in termedinte (MICs, 0.094-0.25 microgram/ml). Penicillin-susceptible strains were also susceptible to the other 4 tested beta-lactams. In penicillin non-susceptible strains, 11.4% (4/35) isolates were resistant to the other beta-lactams. The resistant rates of erythromycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole (TMP-SMZ) were 74.0%, 87.6%, 47.8%, 63.3%, respectively. All of the strains were susceptible to vancomycin and rifampin. 119/244(48.7%) strains isolated were multiresistant to tetracycline, erythromycin and TMP/SMZ. Serotype 6A(33.6%), 19F(16.8%), 23F(15.1%), 15(11.2%), 6B(4.3%) were most common. 57.1% (20/35) penicillin non-susceptible strains were of serotype 23F and had similar or identical multiresistance and BOX patterns. CONCLUSION: In Beijing, the prevalence of penicillin-resistant pneumococci was obviously lower than that of neighboring countries, but resistant rate to non-beta-lactams was high. The epidemic multiresistant 23F clone found in day-care centers was different from the Spanish clone.

Anti-Bacterial Agents↗
PubMed1999

[Association of serum leptin concentrations with blood pressure].

OBJECTIVE: To explore the relationship between serum leptin, hypertension, body mass index (BMI) and energy metabolism. METHODS: Serum leptin concentrations were measured by radioimmunoassay. Blood pressure (BMI) blood sugar (Glu), triglycerides (TG), total cholesterol (TC), LDL, HDL, BUN, Cr and Ur were determined in 64 men with essential hypertension (EHT) and 54 male normotensives (NT). The correlation between leptin and other parameters were analyzed. RESULTS: (1) Serum leptin concentrations n = 118 (3.3 +/- 1.9) micrograms/L in 118 subjects were significantly correlated with SBP, DBP, BMI, Glu, TG, TC and LDL(P < 0.05-P < 0.001). (2) Serum leptin concentrations were strongly correlated with BMI in both EHT and NT groups (P < 0.001). The concentration level was significantly higher in EHT group n = 64 (3.8 +/- 1.9) micrograms/L than in NT group n = 54, (2.8 +/- 1.3) micrograms/L, P < 0.01). The difference in serum leptin concentrations between the two groups disappeared when BMI and age were corrected by analysis of covariance. In NT group, serum leptin concentrations were correlated with SBP (P < 0.05). (3) If the cases of overweight, underweight, hyperglycemia, hyperglyceridemia were excluded, serum leptin concentrations were still highly correlated with BMI, but no longer related to blood pressure. CONCLUSION: Serum leptin concentrations are not directly related to blood pressure, but the concentration levels are actually correlated with the degree of obesity and energy metabolism.

Blood Pressure↗
PubMed1999

Serum leptin levels and adiposity in adult Chinese: a preliminary observation.

OBJECTIVE: To establish normal serum leptin levels in Chinese and investigate the relationship between serum leptin levels and body fat, gender, age and androgen. METHODS: Serum leptin levels were measured in 77 lean (BMI < 25) and 28 overweight or obese (BMI > or = 25) subjects by a radioimmunoassay (RIA) method. RESULTS: The serum leptin levels in lean Chinese were 2.15 +/- 1.46 ng/ml in male and 7.85 +/- 3.60 ng/ml in female, which are similar to those of Caucasians, while in overweight or obese ones, the levels were 4.87 +/- 3.47 ng/ml and 16.59 +/- 6.92 ng/ml respectively, lower than those in Caucasians. A 2-3 times higher leptin concentrations were found in women than in men in both conditions. Even when the number of lean males was expanded to 79 subjects aged from 17-80 years, no significant leptin-age relationship was found. Despite 25% of obese subjects manifested a relative deficiency of leptin, as a whole, leptin levels in both men and women were significantly correlated with BMI (r = 0.69, P < 0.001 in male and r = 0.63, P < 0.001 in female). CONCLUSIONS: Serum leptin levels in Chinese lean people are similar to those in Caucasians and in both lean and obese groups, the leptin levels are correlated with BMI, suggesting that the great majority of the obese patients are resistant to endogenous leptin. Those who are relatively deficient of leptin may become a group of good candidates for leptin treatment in the future.

Adult↗
PubMed1999

Progress in schistosomiasis control in China.

PURPOSE: To briefly review schistosomiasis situation in the past, progress in the control program and problems to be solved. DATA SOURCES: Data from literature published at home and abroad on the control and research of schistosomiasis in China in biomedical journals and monographs, and a few data from the Office of Endemic Diseases Control, Ministry of Health, are collected. STUDY SELECTION: Information on this topic are screened and the important ones are selected. RESULTS: Schistosomiasis in China was serious. Through hard work for control for half decade, great progress has been achieved after implementation of the control program. Control approaches are introduced. Compared with data in the early 1950s, endemic provinces decreased from 12 to 5, infected persons, from more than 10 million to around 865,000, and the areas of Oncomelania snail habitats, from 14 billion m2 to 3.6 billion m2. Proportion of symptomatic patients among those infected has a significant reduction. The national criteria for control and elimination of schistosomiasis in China are introduced. CONCLUSIONS: The achievements of schistosomiasis control are tremendous but the tasks in China are arduous. Especially after last year's heavy flood, areas of snail habitats are increasing. To consolidate the success and to put the still endemic areas under control are long-term and arduous tasks confronting China.

Animals↗
PubMed1999

Spontaneous activation of hamster oocytes in vitro.

OBJECTIVES: To observe the time of spontaneous activation of hamster oocytes and to find out the early signs of hamster oocytes activation. METHODS: First, 63 hamster oocytes including activated and non-activated oocytes (group A) and 51 non-activated oocytes (group B) were injected with human sperm and checked for fertilization after 16-18 hours. Then, 20 hamster oocytes were cultured in vitro in medium with or without calcium and examined under light microscope every half an hour up to 9 hours. RESULTS: Under light microscope, hamster oocytes activation were observed to undergo 4 stages: metaphase II stage without meiotic spindle, appearance of meiotic spindle near the first polar body, protrusion of oolemma, and complete extrusion of second polar body with pronucleus formation. After culture for 1.5 hours in vitro, 30%-40% of the oocytes demonstrated meiotic spindle; but after 9 hours, 50% showed complete activation. Culture in medium without calcium showed a little delay in the process of activation. The earliest sign of spontaneous activation in hamster oocytes was the appearance of meiotic spindle near the first polar body. Although group A and B showed no difference, the damage rate was lower in group B (19.7% +/- 16.6%) than in group A (35.9% +/- 5.7%) (P = 0.08), whereas the fertilization rate (18.3% +/- 10.9%) was higher in group B than in group A (14.2% +/- 8.7%) (P = 0.135). CONCLUSIONS: Hamster oocytes may be activated spontaneously early after their removal. It is important to recognize the earliest sign of spontaneous activation and perform intracytoplasmic sperm injection (ICSI) before it happens.

Animals↗
PubMed1999

Effect of integrin on procollagen synthesis by fibroblasts from scleroderma.

OBJECTIVE: To investigate the effect of integrin on fibroblasts from scleroderma in the production of procollagen. METHODS: Phosphorothioate modified antisense oligonucleotides were used to interfere with the expression of integrin alpha 5 or beta 1 subunit on fibroblasts from 10 cases of scleroderma, and then the changes of procollagen mRNA due to the decline in level of integrin were observed by using RT-PCR. RESULTS: Expression of integrin alpha 5 or beta 1 subunit was specifically inhibited by their corresponding antisense oligonucleotides. Fibroblasts with decreased expression of alpha 5 or beta 1 subunit produced lower level of procollagen alpha 1 (I), alpha 1 (III) mRNA in comparison to the control. CONCLUSION: Overproduction of procollagen may be inhibited at the level of transcription by lowering the expression of integrin alpha 5 or beta 1 subunit on fibroblasts in scleroderma.

Adult↗
PubMed1999

[Short-term effect of navelbine on non-small cell lung cancer in 48 cases].

OBJECTIVE: To evaluate effect of navelbine on non-small cell lung cancer (NSCLC). METHODS: Forty eight cases of cytologically and pathologically confirmed advanced NSCLC were treated with combined chemotherapy including navelbine as the cardinal drug from May, 1995 to January, 1988. They were randomly divided into two groups. One group of 20 cases was treated with NP regimen (NVB + PDD); the other group of 28 cases was treated with NI regimen (NVB + IFO). All patients received no previous treatment. RESULTS: There was no complete response in patients treated with either regimen. Partial response was observed in 8 of 20 NP-treated patients(40.0%) and in 12 of 28 NI-treated patients (42.8%). There was no statistical difference in response rate between these 2 groups of NSCLC patients. However, in both groups of patients, the therapeutic effect was better in adenocarcinoma than in sequamous-cell carcinoma patients. NP regimen seemed effective in the control of bone metastases and pains. Side effects were mainly myelo-suppression and digestive tract reaction. CONCLUSION: Combined chemotherapy including NVB is worthy of use in the treatment of advanced NSCLC especially for those with bone metastasis.

Aged↗
PubMed1999

[The features of coronary angiography in coronary heart disease with non-insulin-dependent diabetes mellitus].

OBJECTIVE: To study the clinical and angiographical characteristics of coronary heart disease (CHD) in CHD patients with non-insulin-dependent diabetes mellitus (NIDDM). METHODS: The study was carried out by case control analysis of the clinical manifestations and the data from cine selective coronary angiography. RESULTS: CHD patients with NIDDM tended to have multiple cardiovascular risk factors. It is likely that NIDDM contributed more to dyslipidemia in the female than in the male. Unstable angina pectoris was found more frequently in CHD patients with NIDDM than in those without. The female CHD patients with NIDDM were more frequently afflicted with myocardial infarction. Moreover, CHD patients with NIDDM had much greater extent of coronary vessel involvement and more diffuse vascular lesion. CONCLUSION: The clinical and angiographical findings are quite different in CHD patients with and without NIDDM. The lesions in the coronary arteries tend to be more severe and diffuse in patients with NIDDM.

Adult↗
PubMed1999

[Experimental study of immunization of mice with hepatitis C virus genetic vaccine constructs].

OBJECTIVE: To inquire into the immune responses to expression protein in mice immunized with genetic vaccine of hepatitis C virus (HCV) and lay a foundation for HCV genetic vaccine development in future. METHODS: The gene fragments coding C and most E regions of HCV-II type were inserted into pCD-SRalpha(1) of eukaryotic expression vector and formed genetic vaccine constructs of pCD-HCV(1) and then was injected into the quadriceps muscles of Balb/c mice. The serum anti-HCV level of mice was tested by ELISA and peripheral blood mononuclear cell (PBMC) proliferative responses to HCV antigens were detected by (3)H-TdR incorporation method (cpm). RESULTS: The serum antibody level reached to 0.71 +/- 0.08 - 0.77 +/- 0.06 (A value, the same below) after genetic vaccine pCD-HCV(1) (100 microg/mouse) were inoculated into the mice (n = 12) three or four times while blank vector pCD-SRalpha(1) could not induce the mice (n = 8) to generate antibody response in same way. After the antibody levels in mice (n = 8) immunized by pCD-HCV(1) had ascended to peak value (0.71), there was no trend of descending during the following 18 weeks of detection (0.68 +/- 0.06 - 0.75 +/- 0.07). Specific fragment of HCV cDNA identified by polymerase chain reaction (PCR) from DNA extracted from the muscles of the mice after pCD-HCV(1) had been inoculated three months. PBMC proliferative responses to HCV synthetic peptides CP(9) and gene recombinant antigens C, E(1) in the mice immunized with pCD-HCV(1) were detected and its stimulation indexes (SI) were 4.07 +/- 1.58, 3.88 +/- 0.70 and 3.69 +/- 1.13 respectively and there was a significant difference (P < 0.001) as compared with that of PBMC in mice immunized with pCD-SRalpha(1). CONCLUSION: These investigations demonstrated that genetic vaccine constructs made of HCV structural region can induce Balb/c mice to generate antibody and PBMC proliferative responses to HCV antigens via DNA immunization.

Animals↗
PubMed1999

[Dynamic effect of the blood glucose and insulin on serum leptin concentration during oral glucose tolerance test].

OBJECTIVE: To investigate the effects of internal change of plasma glucose and serum insulin levels on serum leptin concentrations during oral glucose tolerance test (OGTT) in normal subjects and type II diabetics (DM). METHODS: Plasma glucose, serum insulin and leptin concentrations were measured simultaneously in 50 age, sex and body mass index matched non-diabetic (non-DM) and 50 DM subjects who were undergoing OGTT. RESULTS: The fast serum leptin concentrations were (3.88 +/- 0.64) microg/L in DM males and (8.30 +/- 1.06) microg/L in DM females. Respectively they were (5.01 +/- 0.64) microg/L and (10.48 +/- 1.30) microg/L in non-DM group. No significant difference was revealed. Comparing with the non-DM group, the glucose curve was elevated and the insulin releasing curve was characterized by a low response and a delayed peak in DM group. As for the leptin releasing curve, both groups showed a decreasing trend, which seemed to be more evident in DM group. CONCLUSION: Leptin concentration does not increase with the release of insulin. On the contrary, it shows a diurnal rhythmic descending trend, suggesting that in vivo, the insulin effect on serum leptin concentration is relatively weak and not able to affect the day-time descending trend of leptin levels.

Blood Glucose↗
PubMed1999

[Effects of epidermal growth factor, basic fibroblast growth factor and 5-fluorouracil on human retinal pigment epithelial wound closure in vitro].

OBJECTIVE: To study the effects of epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) and 5-fluorouracil (5-Fu) on the cell migration and proliferation. METHODS: Phase-contrast microscopy, cell proliferation assay and wound -closure were used to study the process of cell proliferation and wound healing in a model of human retinal pigment epithelial (RPE) cell damage. RESULTS: It was found that EGF mainly stimulated proliferation and the migration of individual RPE cells from the wound edge, and induced cellular elongation, while bFGF mainly promoted proliferation and spread of the confluent monolayer into the wound defect, and induced enlargement and flattening of cells. But the effects of EGF, bFGF on wound closure were not very significant; 5-Fu inhibited the spread and proliferation of RPE cells, but had no effects on cell migration. CONCLUSIONS: EGF and bFGF have no significant effects on wound-healing, perhaps their effects on cell morphology are very important in cell transformation in proliferative vitreoretinopathy (PVR), and 5-Fu can only be a subsidiary drug to prevent PVR.

Cell Division↗
PubMed1999

[A prevalence study on hepatitis C infection in 4,055 healthy children of Beijing].

OBJECTIVE: To understand the prevalence of hepatitis C (HC) infection in children of urban Beijing. METHODS: Serum antibodies against hepatitis C virus (anti-HCV) and HCV RNA were determined with enzyme-linked immunosorbent assay (ELISA) in 4 055 healthy children under 14 years of age living in four urban districts of Beijing. RESULTS: Fourteen children were positive for anti-HCV, and four of them were positive for HCV RNA as well, with a prevalence of HCV infection of 0.35%. There was no significant difference in prevalence of HCV infection between children living in different districts and by sex and age. However, very significant difference in prevalence of HCV infection between children with history of blood transfusion and injection of human blood-derived globulin and those without it. The parents of 14 children with positive anti-HCV were all negative for it. CONCLUSION: Blood-borne transmission still was the main route for HCV infection in children.

Adolescent↗
PubMed1999

[Expression of bcl-2, bax and p53 protein in the basal cell carcinoma].

The expression of bcl-2, bax and p53 protein was studied in the basal cell carcinoma with 32 patients by immunohistochemical method. The results showed that bcl-2 protein was positive in 26 patients (81.2%), bax protein was positive in 9 patients(28.1%), and p53 protein was positive in 13 patients (40.6%); there is a negative correlation between the expression of bcl-2 and bax protein(P < 0.05). These findings suggest that apoptosis is suppressed which might cause the production of basal cell carcinoma.

Aged↗
PubMed1999

[Study on the radioligand binding assay of cholecystokinin receptor in rat cerebral cortex].

A radioligand binding assay system for determining the characterization of CCK receptor is presented. Using Bolton-Hunter reagent, we prepared a biologically active, specific 125I-BH-CCK8. The iodination mixture was then transferred to a column of Sephadex G-25 and examined by silica thin layer chromatography. Its specific activity and radiochemical purity were 3.4 TBq/mmol and 96% respectively. Binding of 125I-BH-CCK8 to the membrane of rat cerebral cortex was rapid, reversible, time-temperature dependent, saturable and specific. The labeled CCK was shown to have biological activity as measured by the CCK receptor radioassay. Under our laboratorial conditions, the CCK binding required an hour to reach equilibrium at 4 degrees C. We chose polyethylene glycol 6,000 and gamma-globulin protein for the separation of B and F. Scatchard plot of CCK binding was linear with a Kd value of 1.098 nmol/L and Bmax of 197.5 fmol/mg protein. The results of this study support the stand-point that CCK may function as a regulatory peptide in brain and hence may be of use for clarifying the CCK receptor's function in central nervous system.

Animals↗
PubMed1999

[Application of enzyme-linked immunosorbent assay for cholecystokinin].

An enzyme-linked immunosorbent assay for octapeptide cholecystokinin (CCK) has been developed. Using this method we distinguished two kinds of CCK-related peptides and is also useful for identified the compounds with CCK-like structure in tissue extracts, as well as different antipeptide antisera. The results showed that this method could be applied to preliminary structure analysis of CCK.

Animals↗