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Biomedical subjects

Y Chen

Publications and source records attributed to Y Chen.

At least 631 records · Page 35Linked to original sources
PubMed2001

[Non-filamentous activated sludge bulking caused by the deficiency of nitrogen].

The effect of nitrogen deficiency on activated sludge bulking was studied specially in some experiments carried on a sequencing batch reactor fed with beer wastewater in this paper. The experimental results showed that the sludge settled properly at a influent BOD/N value of 100/4. When the value of BOD/N was 100/3 and 100/2 respectively, non-filamentous activated sludge bulking caused by an excessive growth of viscous Zoogloea with high moisture content occurred. When the value of influent BOD/N was 100/0.94, more serious non-filamentous bulking occurred. Furthermore, the effect of nitrogen deficiency on the nitrogen sources and phosphorus sources utilization rate and the COD removal rate was studied in the experiments.

Bacteria↗
PubMed2001

[Diagnosis and treatment of 31 patients with splenic tumors].

OBJECTIVE: Splenic tumor, a rare disease, is scarcely mentioned in the literature. Here, we wish to present a clinical study on 31 such patients treated in the PLA General Hospital with emphasis on diagnosis and treatment. METHODS: Thirty-one splenic tumor patients were treated from January 1990 to December 2000. The clinical manifestations and image characteristics of splenic tumor, diagnosis and treatment were analysed. RESULTS: Male 19, female 12. Their ages ranged from 13 to 80 years with an average of 56. The symptoms and signs were non-specific. All patients were first diagnosed by beta-ultrasonography to have single or multiple space-occupying lesions. Then, 19 patients received CT and 7 MRI scans. The diagnosis of seven patients suffering from splenic cysts were initially made definite by beta-ultrasonography among whom the lesions of 6 were confirmed by operation and pathology. The diagnosis of 9 patients with metastatic tumor was ascertained by combined imaging and clinical history. Finally, the lesions were confirmed by operation and pathology. Fifteen patients with primary splenic tumor were found to have primary space-occupying lesion by imaging: Except one patient who was diagnosed to have splenic lymphoma and not operated, all the other 14 patients underwent splenectomy with their lesions confirmed by pathology. Altogether, 25 of these 31 patients were treated by splenectomy with uneventful recovery without any operative mortality. Final pathologic examination disclosed that 20(65%) of 31 lesions were benign. CONCLUSION: Clinical history and imaging scans are important in the diagnosis of splenic tumors. The differentiation of benignity and malignancy is difficult before operation. Surgery is satisfactory in treating splenic tumors.

Adolescent↗
PubMed2001

[Analysis on the epidemiology of syphilis in Guangdong province from 1995 - 1999 and the strategy for syphilis control].

OBJECTIVE: To explore the epidemiologic characteristics of syphilis in Guangdong province based on the data from 1995 - 1999 in the province and to provide reference for further control of the disease. METHODS: Registered cases of syphilis were collected in every city/county and the data was analyzed epidemiologically. RESULTS: The incidence rate of syphilis in Guangdong province increased rapidly the past five years, went up from 1.81 per 100 thousand residents in 1995 to 15.17 per 100 thousand residents in 1999 with an average increase as high as 133.37%. The proportion of syphilis in the eight-reportable STD also increased annually with an average annual increase rate of 125.40%. Among the cases, primary cases were dominant accounting for 91.02%. Most patients were males with 20 - 29 year olds accounted for the majority. As for education level, the majority of the patients were middle school graduates. The most popular way of transmission was through extra-marrital sexual contact which accounted for 77.31%. Syphilis patients were mainly seen in coastal cities such as Guangzhou and Shenzhen. CONCLUSION: Based on the epidemiologic feature of syphilis in Guangdong, following measures should be taken in order to control the disease: to enhance the STD knowledge through education, to promote the widely use of condoms and to standardize the diagnosis and treatment of syphilis.

Adolescent↗
PubMed2001

[Association between apolipoprotein E polymorphism and Alzheimer's disease: A population-based study in Guangzhou, China].

OBJECTIVE: To investigate the distribution of apolipoprotein E (apoE) genotype of patients with Alzheimer's disease (AD) in the population aged 75 and older in Guangzhou and to determine whether there was an association between AD and apoE epsilon4 allele. METHODS: A systematic cluster sampling design, two-stage screening and field evaluations were used in a cross-sectional population-based study. Three thousand eight handred and twenty-five subjects aged 75 and above in Liwan district of Guangzhou were interviewed. Blood samples were collected from 110 cases and 518 normal controls. The criteria of DSM-III-R and NINCDS-ADRDA were used for clinical diagnosis of probable AD. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to determine apoE genotypes. RESULTS: There were 190 cases diagnosed as sporadic AD from this sample. The frequencies of the three apoE alleles were detected as follows: epsilon2 = 0.100, epsilon3 = 0.832, epsilon4 = 0.068 in AD patients; epsilon2 = 0.092, epsilon3 = 0.843, epsilon4 = 0.065 in normal controls. The frequencies of apoE genotype and allele in the AD patients were not significantly different from that in normal subjects (P > 0.05). CONCLUSION: No association between sporadic AD and apoE epsilon4 allele was found among the population aged 75 and above in Liwan district of Guangzhou.

Aged↗
PubMed2001

[A study on relationship between blood lead level in children and fetal umbilical cord].

OBJECTIVE: To study the relationship between blood lead level in children and fetus. METHODS: Blood specimens were collected from the fingers of children aged one to five years and from umbilical cord when the babies were born, to determine their lead level with atomic absorption spectrophotometry. RESULTS: The average blood lead level was (0.42 +/- 0.15) micromol/L in 1 122 children. Blood lead level in 27.54% of the children was above >/= 0.483 micromol/L. The average umbilical blood lead level was (0.16 +/- 0.12) micromol/L in 127 neonates. Blood lead level in 0.79% of the new-born babies were greater than >/= 0.483 micromol/L. CONCLUSION: Higher blood lead level in children was mainly caused by environmental pollution and unhealthy life behaviors. Background blood lead in fetuses has already reached a higher level, so prevention from lead poisoning in children should begin during pregnancy.

Child, Preschool↗
PubMed2001

[Studies on the change of extracellular matrix in the corneal tissue after photorefractive keratectomy in rabbits].

OBJECTIVE: To investigate the relationship between the haze formation and the change of extracellular matrix (ECM) in the corneal tissue after photorefractive keratectomy (PRK). METHODS: Twenty-four adult New Zealand White rabbits received PRK in the right eye for minus sign10.00 D ablation. According to the time of rabbits sacrifice, they were divided into 8 groups, and 3 rabbits were in each group. They were immediate, 24 hour, 1 week, 2 week, 1 month, 3 month, 6 month and 12 month groups. After surgery, the corneas were examined periodically by slip-lamp microscopy for haze formation. The right eyes were enucleated, and the corneas were studied with immunohistochemical evaluation for extracellular matrix, including collagen type I, type III, type VI, cellular fibronectin, tenascin and laminin. RESULTS: The incidence of haze was 100% after PRK. The formation of haze had a tendency from mild to severe, and along with the time prolongation, it gradually decreased and disappeared. The newly synthesized collagen type I, type III, type VI, cellular fibronectin, tenascin and laminin were deposited in the anterior corneal stroma. CONCLUSION: The formation of haze is closely related to the deposition of ECM elements in the anterior corneal stroma in the surgical area.

Animals↗
PubMed2001

[The hEGF expression of gene--transferred human epithelium after its grafting on porcine surgical wound].

OBJECTIVE: To investigate the hEGF expression of gene -- transferred human epithelium after its grafting on porcine surgical wound. METHODS: Gene -- transferred and normal epithelia were implanted on the biological silicone membrane and then grafted on porcine surgical wound. The tissue samples were harvested from the wound and detected for the hEGF expression with immunohistochemical method on 1, 3, 5, 8 and 12 post -- grafting days. RESULTS: There existed positive hEGF expression in the wound grafted with gene -- transferred epithelia and negative hEGF expression in the wound grafted with normal epithelium. CONCLUSION: Gene -- transferred epithelium could express hEGF on the grafted wound.

Animals↗
PubMed2001

[An experimental study on the effects of NGF on the wound healing of deep partial thickness burn in pigs].

OBJECTIVE: To investigate the effects of nerve growth factor (NGF) on wound healing of deep partial thickness burn in pigs. METHODS: Six pigs of about 20 kg each were employed as the model. Twenty -- four deep partial thickness burn wounds (2.5 cm in diameter per wound) were made on the back of each pig by temperature and pressure controller. Six wounds were set to be one group. The wounds were randomly divided into 4 groups, i.e. control group (applied with normal saline, C), three treatment groups with NGF topically applied in doses of 1, 2.5 and 5 microgram/ml, respectively. Histological examination, determination of hydroxyproline, analysis of cellular DNA cycle and wound healing time in every groups were carried out on 3, 5 and 9 postburn days (PBD). RESULTS: The proliferation rate of epithelia was much more active in treatment groups than in control group. Epithelization of the wound in treatment groups was earlier than of that in control group. The hydroxyproline content in treatment groups exhibited an increment after a prior decrement, especially on 5 PBD when the content was much lower in the treatment groups. The analysis of cellular DNA cycle indicated that cell number of S phase in treatment groups was obviously more than that in the control group. Furthermore, the wound healing time in treatment groups was much shorter than that in control group. CONCLUSION: Local application of NGF might promote the wound healing of deep partial thickness burn.

Animals↗
PubMed2001

[The significance of the postburn expression of proto -- oncogenes c -- fos and c -- myc mRNA and proteins in rat myocardial cells].

OBJECTIVE: To investigate the postburn expression of proto -- oncogenes c -- fos and c -- myc mRNA and proteins in rat myocardial cells following severe burn. METHODS: Wistar rats inflicted with 30% TBSA III degree burn on the back were employed as the model and randomly divided into four groups: burn (B), resuscitation (R), verapamil (V) and control (C) groups. The expressions of c -- fos and c -- myc mRNA were examined by in situ hybridization and that of the proteins by immunohistochemistry. RESULTS: The expressions of the proteins and mRNA of c -- fos and c -- myc in every experimental groups increased to peak values and then decreased along with time lapsing. And the expressions of c -- fos and c -- myc were weakest in B group, while that in V group was stronger than that in R group. CONCLUSION: The expression of postburn immediate -- early genes c -- fos and c -- myc could be induced in the myocardial cells in all the groups by severe burns. And the expression features were different from the gene expression in patients with myocardial infarction and with cardiac over -- load. This implied that there were different signal transduction and modulation mechanism among these pathological conditions.

Animals↗
PubMed2001

[The adherence of leukocytes mediated by L-selectin to endothelia activated by burn sera].

OBJECTIVE: To study the mediating effects of L-selectin on the adherence of rat PMNs to the endothelia activated by burn sera. METHODS: Pulmonary microvascular endothelial cells (PMEC) of rat were cultured by tissue block method. Rat PMNs were harvested by continuous perfusion. The samples were collected for the detection of the adhering rate of PMEC to the PMNs after being cultured with L-selectin monoclonal antibody (mAb), L-selectin ligand and sulfatide, respectively. RESULTS: The adhering rate of PMNs to PMEC was obviously lowered by the adding of L-selectin mAb and sulfatide. CONCLUSION: The adherence of PMNs to activated PMEC could be mediated by L-selectin.

Animals↗
PubMed2001

[The induction of high-level expression of a novel VL-30 like gene during the chemical-inducing erythroid differentiation of murine erythroleukemia cells (MEL)].

OBJECTIVE: To study the gene expression during the chemical inducing erythroid differentiation of murine erythroleukemia cells (MEL). METHODS: Differential display assay was used to analyze the gene expression before and after the induction differentiation of MEL cells by DMSO and hemin; and then, the flanking sequences of one of the cDNA fragment was amplified by modified rapid amplification of cDNA end (RACE) method, Northern blot analysis was adopted to characterize the expression of this gene. RESULT: The expression of a new transcript similar to VL-30 retrotransposon family increased significantly during the chemical inducing erythroid differentiation in MEL cells. The cloned cDNA is 1883bp, and it is highly homologous to the internal region of murine BVL-1 (1,955-4,000 nt). At least three transcripts in MEL cells were detected by Northern hybridization and all of them increased after the induction. CONCLUSION: A new VL-30-like gene is identified for the first time in MEL cells during chemical inducing erythroid differentiation.

Animals↗
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

[Literature researches of Herba Lagopsis].

The usage of Herba Lagopsis as a drug has a long history, and it was arranged under the item of Semen Leonuri in the herb books of past dynasties and used as a kind of Semen Leonuri. The alias of Semen Leonuri is Spica Prunellae in records, and the withered Semen Leonuri after the summer solstice is also Herba Lagopsis. Now, there are many Flora and local Flora and records of materia medica embodying it, and its function is similar with motherwort.

History, Ancient↗
PubMed2001

[Expression of mRNA of osteocalcin in condylar cartilage of young SD rats after functional protrusion].

OBJECTIVE: To study the temporal and spatial patterns of the expression of mRNA in condylar cartilage of young growing SD rats, in condition of different functional treatment time span. METHODS: SD rats are randomly divided into 3 groups: control, all-day group (wearing functional appliance for 24 hours a day) and 12-hour group (wearing appliance for 12 hours in daytime). After one week, animals are sacrificed and Osteocalcin mRNA expression is studied by in situ hybridization using Oligonucleotide probe, calculated by image processing and macroscopic and microscopic statistics. RESULTS: Osteocalcin mRNA is expressed in condylar cartilage of young growing SD rats and the acrophase is around 6:00 am. After wearing the functional appliance, the intensity in all-day group rises more than that in 12-hourgroup. CONCLUSIONS: Better results can be achieved in all-day group with functional appliance.

Animals↗
PubMed2001

[Effect of PCNA antisense oligooxynucleotides and VEGF antisense oligoxynucleotides on growth of hepatocellular carcinoma transplanted in nude mice].

OBJECTIVE: To study the inhibitory effect of PCNA antisense oligonucleotides or/and VEGF antisense oligonucleotides on growth of human hepatocellular carcinoma in nude mice. METHODS: Human hepatocellular carcinoma transplanted subcutaneously in nude mice model was established, and subsequently was divided into four groups: PCNA-ASODN group, VEGF-ASODN group, combined group and control group. Different treatments were given respectively. The weigh and volume of subcutaneous tumors was measured, and the morphological changes of tumor cells was observed under microscope. RESULTS: The growth inhibitory rate in the PCNA-ASODN group was 72.8%, 44.9% in the VEGF-ASODN group, and 87.2% in the combined group. The combined group which was treated with PCNA-ASODN and VEGF-ASODN showed more effective inhibitory than the PCNA-ASODN group or the VEGF-ASODN group respectively. CONCLUSIONS: The growth of human hepatocellular carcinoma in nude mice can be inhibited by PCNA antisense oligonucleotides and VEGF antisense oligonucleotides respectively. Better inhibitory effect can be obtained if PCNA antisense oligonucleotides and VEGF antisense oligonucleotides are combined in use.

Animals↗
PubMed2001

[Experimental and clinical studies of recombinant human growth hormone treatement of hypoproteinemia of liver cirrhosis patients].

BACKGROUND: To assess the effect of recombinant human growth hormone (rhGH) therapy to liver cirrhosis patients with hypoproteinemia. METHODS: 31 liver cirrhosis patients were treated with rh GH (0.25 IU/kg/day-) and 20 such patients with human albumin (10 g/day) as control all for 10 days. Serum levels of growth hormone (GH), insulin-like growth factor (IGF)-1 and albumin (ALB) were measured by radio-immunoassay before 24h and after 24h and 10 days of rhGH therapy. Serum levels of GH and IGF-1 of 10 age matched healthy subjects were also measured. RESULTS: As compared with healthy subjects, the pretreatment serum GH level of liver cirrhosis patients was high (4.96 +/- 3.97 vs 1.62 +/- 2.26, P <0.05), and the IGF-1 level was markedly lower (36.53 +/- 12.77 vs 56.95 +/- 16.46, P <0.01). After 10 days of rhGH administration, the serum IGF-1 and ALB levels of the treated group increased significantly as compared with the control group (P <0.01). CONCLUSIONS: Exogenous rhGH therapy can overcome the GH resistance of liver cirrhosis patient s and can increase significantly the serum albumin level as compared with the control group who were treated with human albumin only.

Female↗
PubMed2001

Expression, Purification, Characterization of Amphioxus Insulin-like Peptide and Preparation of Polyclonal Antibody to It.

To elucidate the origination and evolution as well as structure-function relationship of insulin and IGF-1, the gene of amphioxus insulin-like peptide (ILP), a common ancestor of insulin and IGF-1, was chemically synthesized and cloned into the expression vector pVT102-U. In the recombinant ILP, the C-terminus of B-domain and the N-terminus of A-domain of amphioxus ILP deduced from cDNA were linked together by a tripeptide, Ala-Ala-Lys, and its B28Arg residue was also replaced by Lys to facilitate its conversion to a double-chain form by Lys-C cleavage. The expression vector was transformed into yeast cells and the recombinant ILP was expressed efficiently. The purified single-chain and double-chain ILP was obtained by fermentation, purification and enzymatic cleavage. Molecular weight measurement and amino acid composition analysis showed that the primary structure of ILP was correct. Circular dichroism analysis showed that the secondary and tertiary structure of double-chain ILP was similar to that of insulin, while double-chain ILP had no measurable insulin activity in insulin receptor binding assay. Additionally, New Zealand Rabbits were immunized with single-chain ILP and high titre polyclonal antibody was obtained. This work was important for further investigating the molecular evolution of insulin and IGF-1 and the distribution and existence of ILP in amphioxus.

Journal Article↗