Biomedical subjects

L Chen

Publications and source records attributed to L Chen.

At least 271 records · Page 15Linked to original sources

PubMed2001

Erythrocyte membrane protein abnormalities in beta-thalassemia of the Li nationality in Hainan.

OBJECTIVE: To determine the composition of abnormal red cell membrane skeleton. METHODS: By sodium dodecyl sulphate polyacrylamide gel electrophoresis of ghostcorpuscles, we quantified the amount of protein by densitometric evaluation. RESULTS: The results showed that in beta-thalassemia, the amount of spectrin, 4.5 protein and globin significantly increased compared with the controls (26.05 +/- 1.46, 21.69 +/- 1.86; 22.87 +/- 5.61, 12.99 +/- 2.33; 15.23 +/- 3.31 and 4.97 +/- 2.73, respectively, P < 0.05). CONCLUSION: These data suggest that the erythrocyte membrane protein composition matched with globin in patients with beta-thalassemia of the racial Li minority are different from the normal control. These factors increase rigidity but decrease deformability of the beta-thalassemic red cell membrane, which may lead to hemolytic anemia.

China↗

PubMed2001

A novel mis-sense mutation (G1381A) in the G6PD gene identified in a Chinese man.

OBJECTIVE: To detect new mutations among 29 glucose-6-phosphate dehydrogenase (G6PD) deficient individuals from Yunnan province. METHODS: The nitroblue tetrazolium (NBT) method was used to screen G6PD deficient individuals. Mutation was identified by single strand conformation polymorphism (SSCP), amplification created restriction site (ACRS), amplification refractory mutation system (ARMS) and DNA sequencing. RESULTS: Among 29 cases, 18 cases of G1388A, 1 case of C1004A, and 1 case of G1381A were identified. Nine cases remained to be defined. The G1381A mutation is a novel mis-sense mutation, with a substitution of threonine for alanine (A461T). The resultant G6PD had reduced enzymatic activity. In addition, G1381A caused a restriction site of Stu I to disappear, providing a rapid method for the detection of this mutation. CONCLUSION: A novel mis-sense mutation G1381A was found. This mutation results in a substitution of threonine for alanine, producing enzyme with reduced activity. The loss of the Stu I restriction site offers a rapid method for the detection of this mutation.

Adult↗

PubMed2001

[Pathological changes between HBeAg and anti-HBe in patients with chronic hepatitis B].

OBJECTIVE: To observe the differences of pathological changes between HBeAg and anti-HBe in chronic hepatitis B. METHODS: Liver biopsy was performed in patients with chronic hepatitis B. The histopathological grading and staging were carried out. Serum markers of viral hepatitis were tested. RESULTS: (1) The histopathological grading and staging were closely correlated with the appearance of serum HBeAg and anti-HBe. The number of G(3-4) and S(3-4) in anti-HBe cases was significantly higher than that of G(1-2) and S(1-2), respectively. The number of G(1-2) and S(1-2) in HBeAg cases was significantly higher than that of G(3-4) and S(3-4), respectively. Significant differences were found between the group of anti-HBe cases and the group of HBeAg cases (P<0.005). (2) HBV DNA was detected in 126 of 151 HBeAg positive patients (83.4%), and the positive rate of HBV DNA in anti-HBe positive patient was 29% only. CONCLUSIONS: (1) Severe inflammatory, necrosis and fibrosis of hepatic tissue are observed in patients with anti-HBe positive chronic hepatitis B. (2) Although HBV DNA is positively correlated to HBeAg, HBV-DNA can be detected in part of anti-HBe positive patients.

Biomarkers↗

PubMed2001

[Study of mechano-sensitive K+ channel in cerebral microvascular endothelial cells from rats].

This study was conducted to gain an understanding of the electrophysiologic characteristics of cerebral microvascular endothelial cells. The stress response of the potassium ion channel in cerebral microvascular endothelial cells was explored. We developed a model of the opening shear stress effect device and used it for calculation of shear stress. The cultured cerebral microvascular endothelial cells from rats were seeded on glass slide of 1 cm x 1 cm. K+ ion channel current was recorded by Patch-Clamp amplifier of Axonpatch 200A type and whole cell Patch-Clamp technique. The inward rectifier potassium current of cerebral microvessel endothelial cells has been elicited by flow stimulus of 1.1 dynes/cm2 shear stress, and there is good relationship between the current and voltage changing. The various stress responses of the cerebral vascular endothelial cells are related to the stress sensitive potassium ion channels of cellular membrane.

Animals↗

PubMed2001

[Piezoelectric ceramic--a novel material for bone replacement].

Based on the piezoelectric effect of nature bone, the biocompatibility of a piezoelectric ceramic and bone tissue is observed and studied in four aspects: cytocompatibility, tissue-compatibility, mechanical compatibility and electro-compatibility. The results show that the piezoelectric ceramic is biocompatible. It is not harmful to the morphology and proliferation of L929. There is osteal combination between the piezoelectric ceramic and bone. Its mechanical properties are also suitable for bone replacement. Especially, it can induce the growth of osseous tissues along the chosen direction according to the piezoelectric properties of bone. It is envisaged that the piezoelectric ceramic may be developed and used as a novel material for bone replacement.

Animals↗

PubMed2001

[Dyslipidaemia and insulin resistance in Chinese in Shanghai].

OBJECTIVE: To investigate the impact of dyslipidaemia on insulin resistance in Chinese individuals in Shanghai. METHODS: 830 individuals aged over 40 years (male 300, female 530) were divided into normal and dyslipidaemia groups. The latter included 7 subgroups as follows: low high density lipoprotein (L-HDL)-subgroup I, high triglycerides (H-TG)-subgroup II, high total cholesterol or high low density lipoprotein (H-TC/H-LDL)-subgroup III, low high density lipoprotein with high triglycerides (L-HDL + H-TG)-subgroup IV, low high density lipoprotein with high total cholesterol or high low density lipoprotein (L-HDL + H-TC/H-LDL)-subgroup V, high triglycerides with high total cholesterol or high low density lipoprotein(H-TG + H-TC/H-LDL)-subgroup VI, low high density lipoprotein with high triglycerides and high total cholesterol or high low density lipoprotein (L-HDL + H-TG + H-TC/H-LDL)-subgroup VII. Homeostasis model assessment (HOMA) was applied to estimate the degree of insulin resistance (IR). RESULTS: (1) Adjusted with age, sex and body mass index (BMI), HOMA-IR was increased in the dyslipidaemia subgroups with high triglycerides. (2) Hypertriglyceridemia was more closely related to raised BMI and waist-hip ratio (WHR). (3) Both body fat (BMI, WHR) and triglycerides were independent risk factors accounting for HOMA-IR. CONCLUSION: Hypertriglycerides could be regarded as an independent risk factor for insulin resistance.

Adult↗

PubMed2001

[Calcium-binding protein S100A2 in the retardation of growth and proliferation of hepatocellular carcinoma cells].

OBJECTIVE: To study the retardation effect of calcium-binding protein S100A2 on the growth and proliferation of hepatocellular carcinoma QGY7701 cells. METHODS: After the plasmid of EGFP-S100A2 had been regrouped and introduced into the hepatocellular carcinoma QGY7701 cells with lipofectin, the expression and location of the products were observed by fluorescent microscopy. The cell growth and proliferation were monitored through cell colony formation in vitro and xenografting subcutaneously in the nude mice in vivo. The effect of S100A2 on the QGY7701 cell cycle was examined with flow cytometry. RESULTS: The chimera protein of S100A2 and green fluorescent protein were detected and appeared to be localized in the cytoplasm and nucleus, while the green fluorescent protein was found to be localized only in the cytoplasm. The cell colony formation of QGY7701/A2 was significantly reduced as compared with the controls. The xenografted tumor of QGY7701/A2 in the nude mice showed a growth at a considerably slower rate than that of QGY7701/pc and QGY7701 groups. The cell cycle review showed retardation of QGY7701/A2 cells in the G1 phase and the DNA content was obviously reduced as compared with the controls. CONCLUSION: The exogenous S100A2 is able to check the QGY7701 cell cycle, stop the cell growth and proliferation either in vitro or in vivo in the QGY7701 cells.

Animals↗

PubMed2001

[The status quo survey of false and inferior species in Chinese medicinal materials market in Hubei Province].

By taking a sample, unqualified varieties were investigated found in Chinese medicinal material examinatorial work near twenty years of six regional level and three countrylish level institutes for drug control and one comprehensive level-three grade-A hospital. By mail, false and inferior species and their origin of Chinese medicinal material were investigated found by sixteen institutes for drug control near ten years in Hubei province. 539 kinds of adulterants (750 cases) including 24 toxic species were found in above-mentioned investigations. Fales and inferior species are rampant in minority regions, which threatens people's health severely. It is urgent for supervising department to gorem the condition strictly.

Drugs, Chinese Herbal↗

PubMed2001

Moderate hypothermia therapy for patients with severe head injury.

OBJECTIVE: To evaluate the effect and safety of early moderate hypothermia therapy (MHT) on patients with head injury by using parallel-control test. METHODS: Thirty patients with severe head injury within 6 hours after accidents were treated by MHT generally for 4-10 days. The other 30 patients with similar head injury treated routinely were enrolled for a parallel-control test. The mortality, morbidity and changes of some neuro-functional indexes as Glasgow Coma Scores, and Glasgow Outcome Scale, levels of endothelin and some other factors of neurobiochemistry in blood plasma were observed. Meanwhile, the dynamic monitoring by transcranial Doppler ultrasonography was conducted in these patients. RESULTS: The mortality in MHT group was significantly lower than that in control group. MHT not only reduced endothelin but also increased the brain biochemical factors, which were helpful to the protection of neurons in the early brain ischemia after head injury. CONCLUSIONS: Early MHT can help reduce mortality and morbidity in patients with acute head injury.

Acute Disease↗

PubMed2001

[Study on drug use in elderly outpatients in Beijing].

OBJECTIVE: To understand the situation of drug use, drug request, combination of drugs and daily drug dose (DDD) among elderly patients, to provide scientific evidences for safely, effectively, economically and rationally on disease prevention and improving the quality of life of the elderly patients. METHODS: A 2-year(1998-1999) prescriptions database which was set up according to different departments of consultation, patient age, sex, consultation date, and name of drugs, dosage was used for the study. Prescriptions were randomly selected on 3-4 days in every month, from 22 hospitals in Beijing. FOXPRO software was used for statistics and analyses. Information of elderly patients (> or = 60 year) on status of drug use, was collected and compared with general patients. RESULTS: The proportion of elderly patients' prescription was 19.9%, with an average number of drugs prescribed in elderly patients 2.71, which was 0.27 higher than that of the general patients. Proportion of injections per every hundred elderly patients prescriptions was 18.4%. The major kinds of drugs were those related to cardiovasculars and vitamins. The most frequent drug was vitamin E nicotinate. DDD on elderly patients was lower than that defined by WHO and drug instruction, but higher than that of the general patients during the same period and was increasing. Daily dose of anti-hypertensions was also higher. The rate of consultation for cardiovascular diseases was high. The ratio of drugs in accordance with national essential drug list was 87.5%. CONCLUSIONS: The rates of elderly patients' prescription, average number of drugs per prescription, proportion of injections and DDD were high. The rational drug use on elderly patients should be given more concerns.

Aged↗

PubMed2001

[Establishment of EBV-immortalized lymphoblast cell lines from three Chinese Fanconi anemia patient and their subtyping].

OBJECTIVE: To establish EBV-immortalized lymphoblast cell lines from Chinese Fanconi anemia (FA) patients. METHODS: The establishment of lymphoblast cell lines was by EBV-immortalization and subtyping of the cell lines by cell fusion, mytomycin C (MMC) inhibition analysis and/or immunoprecipitation and Western blot. RESULT: (1) Three lymphoblast cell lines were established, two of them were sensitive to MMC with a IC (50) < 10 nmol/L. (2) The subtypes of all the three patients belong to FA-A group. CONCLUSION: Complementation analysis was suitable for all FA patients with MMC-sensitive lymphoblastic cell lines, but this method is time consuming. Immunoprecipitation and Western blot are much faster for subtyping but could only be used for FA patients whose related genes had been cloned and specific antibodies been developed.

B-Lymphocytes↗

PubMed2001

[The Immunophenotypical features of t (8; 21) (q22; q22) acute myeloid leukemia].

OBJECTIVE: To study the predictive value of immunophenotypical features in t (8; 21) (q22; q22) acute myeloid leukemia (AML). METHODS: Morphological/cytochemical, flow cytometric immunophenotyping, cytogenetic analyses (MIC) and RT-PCR were performed in 294 previously untreated AML. RESULTS: (1) In 294 AML patients, t (8; 21) AML were 21.8% (64); in AML-M(2), t (8; 21) AML were 54.7%; and in t (8; 21) AML, AML-M(2) were 81.3%. (2) Compared with control group, CD(19) and CD(34) expressions were higher, and CD(33) expression was lower (P < 0.001) in t (8; 21) AML. (3) If the cut-off value of CD(19) positive was >or= 20%, CD(19) positive rate was 13.6% (40/294) in AML, and 50% (32/64) and 3.5% (8/230) (P < 0.001) in t (8; 21) AML and control group. (4) CD(19)(+) and/or CD(34)(+) t (8; 21) AML accounted for 90.6% (58/64) of t (8; 21) AML and CD(19)(-)/CD(34)(-) for 9.6% (6/64). CONCLUSION: In t (8; 21) AML, especially M(2)/t (8; 21), CD(19) and CD(34) expressions were high. CD(19) was one of predictive markers of t (8; 21) AML.

Adolescent↗

PubMed2001

[Affect of As(2)O(3) on the sister chromatid exchanges in human blood lymphocytes].

OBJECTIVE: To assess the potential of As(2)O(3) in inducing malignant transformation at its therapeutic concentrations. METHODS: The sister chromatid exchange (SCE) in human peripheral blood lymphocytes (PBL) treated with different concentrations of As(2)O(3) was detected by the staining technique for sister chromatid differentiation. RESULTS: At 2 x 10(-6)mol/L and 1 x 10(-6) mol/L of As(2)O(3), the SCE frequency in PBLs was significantly increased as compared with the control (P < 0.01). Most of the lymphocytes were arrested at the first cell cycle (M1) and the mitotic index was significantly decreased in a dose dependent manner. At 1 x 10(-7) mol/L or less of As(2)O(3), the SCE frequency, the cell proliferation kinetics and the mitotic index in PBLs were similar to the control (P > 0.05). CONCLUSION: It seemed that As(2)O(3) might induce transformation and affect the function of lymphocytes when used within the therapeutical concentration range.

Arsenicals↗

PubMed2001

[Technical causes of false and inferior species appearing in Chinese medicinal materials markets].

The result indicated that technical causes of false and inferior appearing in the Chinese medicinal materials markets consisted of two respects essentially. First, the men who violated the law and committed a crime used certain weak link existing in quantity analysis of country's medicinal standard. Second, it is difficult that basic units managing and using drug implement effective technical supervision.

Drugs, Chinese Herbal↗

PubMed2001

[Increased cellular proliferation in BEL-7402 hepatoma cells transfected by human hepatic stimulator substance gene].

A hepatotropic factor originally identified in weanling or regenerating rat livers, known as hepatic stimulator substance (HSS), is characterized by promoting markedly liver regeneration after partial hepatectomy. Although HSS gene and the gene product have been described recently, the cellular mechanism of HSS and its genetic function remain obscure. In our previous studies, human HSS (hHSS) was demonstrated to promote the growth of hepatoma cells and phosphorylate the mitogen-activated protein kinase (MAPK). In this study, we reported the growth features of human hepatoma cells response to hHSS gene transfection. The hHSS eukaryotic vector was transfected to BEL-7402 hepatoma cells and the expression of hHSS was analyzed with Northern and Southern blot. The results showed that the HSS recombinant construct was functionally expressed in the target cells as analyzed with Northern blot and reverse transcriptase polymerase chain reaction (RT-PCR). The growth potential of HSS transfected hepatoma cells was markedly enhanced as compared with the non transfected cells. The S-phase of the hHSS-transfected cells increased by 61.5% than that of the non-transfected cells as shown by flow cytometry. Moreover, MAPK phosphorylation, one of the most important mitogenic indexes of growth signal cascade, was profoundly activated at sites of Thr202/Tyr204 due to HSS gene transfer. Based on these results, it is concluded that the introduction of HSS gene into hepatoma cells might be able to stimulate directly the cellular growth in vitro, allowing a possibility of reevaluation of HSS mechanism in intact cells.

Carcinoma, Hepatocellular↗

PubMed2001

[Study on endothelial cell injury in women with pregnancy induced hypertension].

OBJECTIVE: To investigate the mechanisms of endothelial cell injury in women with pregnancy induced hypertension (PIH). METHODS: Human umbilical endothelial cells were cultured in the serum from 10 women with severe PIH and 10 normal pregnant women, and co-cultured with neutrophils or not for 48 hrs. The morphology and cell cycles were studied. RESULTS: Without neutrophils, no apoptotic cells were observed, while neutrophils were added, apoptotic cells were obviously detected. The percentage of apoptotic cells in PIH was more than that in non-PIH. The percentage of cells in G2/M phase decreased in all the groups, but there were no significant differences among them. CONCLUSIONS: Endothelial cells were injured indirectly in PIH patients. Activated neutrophils induced apoptosis might be one of the answers.

Adult↗

PubMed2001

[Nucelotide sequence of an ECHO virus isolated from a meningiti].

BACKGROUND: To determine the nucleotide sequences of W strain (Zhaoyuan/W/87) isolated from a meningitis patient, and compare them with the sequences of relational enteroviruses. METHODS: Virion RNA was transcribed into cDNA by reverse transcriptase, cDNA was amplified by PCR, the products of PCR were purified. Then RNA sequence analysis was performed by the dideoxynucleotide chain termination method using synthetic oligodeoxynucleotide primers. RESULTS: The partial nucleotide sequences of 5 UTR, region 2C and 3D of W strain (Zhaoyuan/W/87) were respectively 244, 275 and 353 nucleotides long. The complete nucleotide sequences of region VP1 were 876 nucleotides long coding 292 amino acids. In comparison with the VP1 sequence of two ECHO29 strains in Genbank through internet, the homogeneity of nucleotide sequence were 82.1% and 81.7%, that of amino sequence were 95.1% and 94.4%. CONCLUSIONS: W strain Zhaoyuna/W/87) was a mutation strain of ECHO29.

Amino Acid Sequence↗

PubMed2001

Homology Modeling of Bacillus subtilis Tryptophanyl-tRNA Synthetase.

Tryptophanyl-tRNA synthetase (TrpRS) plays a pivotal role in protein synthesis. However, till now no stereostructural data of Bacillus subtilis TrpRS were reported. Here, by using the homology modeling using Bacillus stearothermophilus TrpRS as a template, it is demonstrated that the synthetase has 16alpha helices and 5beta sheets. The only tryptophan Trp(92) is located on the interface of subunits. Also the modeling presents the ligand binding site, active site and the putative binding of tRNA(Trp).

Journal Article↗