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Biomedical subjects

K Chen

Publications and source records attributed to K Chen.

At least 91 records · Page 5Linked to original sources
PubMed2001

Effect of satiation on brain activity in obese and lean women.

OBJECTIVE: To investigate the response of the brains of women to the ingestion of a meal. RESEARCH METHODS AND PROCEDURES: We used measures of regional cerebral blood flow (rCBF), a marker of neuronal activity, by positron emission tomography to describe the functional anatomy of satiation, i.e., the response to a liquid meal in the context of extreme hunger (36-hour fast) in 10 lean (BMI < or = 25 kg/m(2); 32 +/- 10 years old, 61 +/- 7 kg; mean +/- SD) and 12 obese (BMI > or = 35 kg/m(2); 30 +/- 7 years old, 110 +/- 14 kg) women. RESULTS: In lean and obese women, satiation produced significant increases in rCBF in the vicinity of the prefrontal cortex (p < 0.005). Satiation also produced significant decreases in rCBF in several regions including the thalamus, insular cortex, parahippocampal gyrus, temporal cortex, and cerebellum (in lean and obese women), and hypothalamus, cingulate, nucleus accumbens, and amygdala (in obese women only; all p < 0.005). Compared with lean women, obese women had significantly greater increases in rCBF in the ventral prefrontal cortex and had significantly greater decreases in the paralimbic areas and in areas of the frontal and temporal cortex. DISCUSSION: This study indicates that satiation elicits differential brain responses in obese and lean women. It also lends additional support to the hypothesis that the paralimbic areas participate in a central orexigenic network modulated by the prefrontal cortex through feedback loops.

Adult↗
PubMed2001

Evaluation of diagnostic criteria for atopic dermatitis: validity of the criteria of Williams et al. in a hospital-based setting.

BACKGROUND: Surveys of the prevalence of atopic dermatitis (AD) have been carried out world-wide, but the results vary widely. The differences probably result from the use of different diagnostic criteria. Williams et al. proposed minimum, simplified, diagnostic criteria that require no invasive test and are easy to use. Pilot studies in European countries showed their suitability for implementation both in hospitals and in the community, and their high sensitivity and specificity. OBJECTIVES: To evaluate the potential practical value of the criteria of Williams et al. in the Chinese population. METHODS: The criteria of Hanifin and Rajka (gold standard), Williams et al. and Kang and Tian were applied and compared in 111 patients with AD and 121 control subjects with other skin diseases in three out-patient centres in China. RESULTS: The criteria of Williams et al. showed a similar diagnostic efficiency to that of the gold standard, with the sensitivity, specificity and kappa value reaching 95.50%, 97.52% and 0.93, respectively. No significant difference was found between the criteria of Williams et al. and those of Kang and Tian (chi2 = 0.69, P > 0.05). 'Onset under the age of 2 years', a criterion of Williams et al. could be used in subjects of any age. CONCLUSIONS: The diagnostic efficiency of the criteria of Williams et al. was basically similar to those of Hanifin and Rajka and of Kang and Tian in our out-patient settings. However, those of Williams et al. were easier to apply and required no invasive tests.

Adolescent↗
PubMed2001

Pharmaceutical cost-containment policy: experiences in Shanghai, China.

BACKGROUND: In the decade after 1983, the annual growth rate of drug expenditure was about four times as high as that of per capita gross domestic product (GDP) in Shanghai. In 1993 and 1994, a drug list policy and hospital revenue capping policy were introduced in Shanghai to contain drug expenditure. We studied the impact of these two policies, as a model for similar policies in other parts of China and elsewhere. METHODS: Quarterly drug expenditure data were collected from 1992 to 1996 and more detailed drug expenditure flow was obtained at seven selected hospitals. Twelve focus group discussions were organized to obtain opinions from all stakeholders. RESULTS: The research findings showed a dramatic and continuing decline in the growth rates of total medical and drug expenditures after the implementation of the two policies. The proportion of total medical expenditure attributable to drugs declined from 67% in 1992 to 51% in 1996. The annual growth rate of drug expenditure per ambulatory visit and per bed-day was reduced as well. Drug revenue as a proportion of total hospital revenue declined gradually in all seven hospitals. The two policies did not alter the equity of drug utilization between the insured and non-insured. The government, insurance authority and state-owned drug enterprises all favoured the new policies, while hospital administrators, professionals, joint venture and foreign manufacturers wished for the reimbursement mechanisms to be improved, for retention of their freedom of choice, and for the drug list to be further expanded. CONCLUSIONS: The drug list and capping policies in Shanghai appear to have achieved their objectives of containing the escalation of drug expenditure and improving the rational use of drugs without loss of equity. The underlying causes of the escalation of drug expenditure in China need to be further elucidated.

Ambulatory Care↗
PubMed2001

Previous pulmonary diseases and risk of lung cancer in Gansu Province, China.

BACKGROUND: Although active smoking is well established as the main cause of lung cancer, there is accumulating evidence that history of prior lung diseases may be an independent risk factor for lung cancer. METHODS: A population-based case-control study in Gansu Province, China identified 886 lung cancer cases (656 male, 230 female) diagnosed between January 1994 and April 1998. A standardized interview collected information on a variety of potential risk factors including a history of physician-diagnosed non-malignant lung diseases (pulmonary tuberculosis, chronic bronchitis/emphysema, asthma, pneumonia), age and year in which each condition was first diagnosed, and any therapy or hospitalization received. RESULTS: Pulmonary tuberculosis (odds ratio [OR] = 2.1, 95% CI : 1.4-3.1) and chronic bronchitis/emphysema (OR = 1.4, 95% CI : 1.1-1.8) were associated with increased risk of lung cancer, after adjustment for active smoking and socioeconomic status. The OR for asthma (OR = 1.4, 95% CI : 0.9-2.1) and pneumonia (OR = 1.5, 95% CI : 1.0-2.3) were also elevated. The risk of lung cancer remained significant for pulmonary tuberculosis and chronic bronchitis/emphysema when analysis was limited to the pathologically confirmed cases and self-responders. CONCLUSIONS: This study provides additional evidence that previous pulmonary tuberculosis and chronic bronchitis/emphysema are causally related to lung cancer, although the precise mechanism is still unclear. The results for asthma and pneumonia, while suggestive of a positive association, did not reach the traditional level of statistical significance and should be interpreted with caution.

Adult↗
PubMed2001

Regulation of human monoamine oxidase B gene by Sp1 and Sp3.

The human monoamine oxidase (MAO) B plays a major role in the degradation of biogenic and dietary amines such as phenylethylamine, benzylamine, dopamine, and tyramine. We previously showed that the -246/-99 MAO B promoter region exhibited the highest activity and contained two clusters of overlapping Sp1 sites, a CACCC element and a TATA box. Here, using a series of 10 deletion constructs of the 2-kilobase pair 5'-flanking sequence, we identified additional potential regulatory elements, including activator proteins 1 and 4, CAAT, GATA, upstream stimulatory factor (USF), estrogen receptor (ER), and sex-determining region Y-box 5 (SOX5). Analysis of nine site-directed mutations of -246/-99 region reveals that both clusters of Sp1 sites contribute positively whereas the CACCC element contributes negatively to the transcriptional activity. Gel shift analysis demonstrates that in addition to Sp1, Sp3 can interact with both clusters of Sp1 sites. Cotransfection experiments show that Sp1 and its closely related family member Sp4 can trans-activate MAO B promoter activity through the proximal cluster of Sp1 sites and its activation can be repressed by the over-expression of Sp3 and a related family member BTEB2. These results suggest that the binding to the overlapping Sp1 sites by various members of Sp family is important for the regulation of the MAO B gene expression.

Base Sequence↗
PubMed2001

Lipoprotein lipase gene mutations and the genetic susceptibility of preeclampsia.

In the pathogenesis of preeclampsia, endothelial cell activation or dysfunction is a central theme, and marked dyslipidemia may contribute to endothelial cell dysfunction. The objective of this study was to evaluate the association between preeclampsia and mutations within the lipoprotein lipase (LPL) gene. DNA was extracted from whole blood or cheek swabs of 250 preeclamptic patients, 265 control subjects, and 106 offspring of preeclamptic patients (all white). Control subjects were women who had undergone >/=2 term pregnancies unaffected by preeclampsia. All samples were genotyped for 3 LPL polymorphisms with the use of polymerase chain reaction of known allelic variants. The 3 mutations studied were the following: (1) Asp9Asn substitution in exon 2, (2) T-to-G substitution at position -93 of the proximal promotor region (-93T/G), and (3) Asn291Ser substitution in exon 6. Results were analyzed with an chi(2) contingency table. The prevalences of the Asp9Asn mutation, -93T/G promotor mutation, and Asn291Ser mutation were not significantly different among the preeclamptic patients and control subjects (Asp9Asn: patients, 2.8%; control subjects, 4.0%; -93T/G: patients, 4.5%; control subjects, 5.5%; Asn291Ser: patients, 4.0%; control subject, 3.0%). In addition, there was no difference in the frequency of any of the mutations in the offspring of preeclamptic women compared with that observed in the control population. Between a small group of patients with nulliparous HELLP syndrome (a variant of severe preeclampsia: hemolysis, elevated liver enzyme, low platelets) patients (n=12) and control subjects, there was a significant difference in the prevalence of the Asn291Ser mutation (16.7% versus 3.0%, P=0.01). In this large white population, the Asp9Asn mutation, -93T/G promotor mutation, and Asn291Ser mutation were not associated with an increased risk for preeclampsia. In a small subgroup of patients, the Asn291Ser mutation was associated with an increased risk for nulliparous HELLP syndrome.

Female↗
PubMed2001

Characterization of the Epha1 receptor tyrosine kinase: expression in epithelial tissues.

The Eph family of receptor tyrosine kinases plays a crucial role during development and is implicated in oncogenesis. Using a partial cDNA clone of an Eph-related kinase (Esk) we isolated the complete coding region of a gene which we show to be murine EphA1 by both structural and functional criteria. The chromosomal localization is shown to be syntenic to hEphA1 and the genomic organization also shows distinct features found in the hEphA1 gene. Functionally, in keeping with findings for the human homologue, both soluble recombinant and "native" mEphA1 show preferential binding to ephrin A1. However, we also observed significant binding to other A-type ligands as has been observed for other Eph receptors. We analysed the expression of mEphA1 mRNA by in situ hybridization on tissue sections. mEphA1 was expressed in epithelial elements of skin, adult thymus, kidney and adrenal cortex. Taken together with previous Northern blotting data these results suggest that mEphA1 is expressed widely in differentiated epithelial cells.

Amino Acid Sequence↗
PubMed2001

Killing effect of TNF-related apoptosis inducing ligand regulated by tetracycline on gastric cancer cell line NCI-N87.

AIM: To clone the cDNA fragment of human TRAIL (TNF-related apoptosis inducing ligand) into a tetracycline-regulated gene expression system, the RevTet-On system, transduce expression vectors into a gastric carcinoma cell line-NCI-N87 and examine the effects of controlled expression of TRAIL in vitro on the gastric carcinoma cells. METHODS: The full-length cDNA of TRAIL was inserted into a vector under the control of the tetracycline-responsive element (TRE) to obtain the plasmid pRevTRE-TRAIL, which was transfected into a packaging cell line PT67. In addition, vector pRev-Tet On and pRevTRE were also transfected into PT67 separately. After hygromycin and G418 selection, the viral titer was determined. The medium containing retroviral vectors was collected and used to transduce a gastric carcinoma cell line NCI-N87. The resulting cell line NCI-N87-Tet On TRE-TRAIL and a control cell line, NCI-N87 Tet On-TRE, were established. TRAIL expression in the cell line was induced by incubating cells with doxycycline (Dox), which is a tetracycline analogue. The killing effect on gastric carcinoma cells was analyzed after induction. RESULTS: The recombinant plasmid pRev-TRE-TRAIL was constructed. After hygromycin or G418 selection, the producer cell lines PT67-TRE, PT67-TRE-TRAIL and PT67-Tet On were obtained,with titers of about 10(8)CFU.L(-1). By transducing NCI-N87 cells with retroviral vectors from these cell lines, stable cell lines NCI-N87-Tet-On TRE-TRAIL (NN3T) and control cell line NCI-N87-Tet-On-TRE (NN2T) were established. The growth curves of the selected cell lines were the same with the wild type NCI-N87. When Dox was added, cell death was obvious in the test groups (29%-77%), whereas no difference was observed in control and wild type cell lines. With the addition of a medium from the test group, human leukemia cell line Jurkat was activated till death (83%), indicating the secretion of active TRAIL proteins from the test cells to the medium. CONCLUSION: With the use of the RevTet-On system, a regulated expression system for TRAIL was constructed. Using this system, the selected killing effect of TRAIL on gastric carcinoma cell line NCI-N87 could be observed.

3T3 Cells↗
PubMed2001

[Effect of radiation with 60Co on RBC membrane elastic shear modulus and membrane viscosity].

RBC membrane shear elastic modulus and membrane viscosity are two important indexes reflecting RBC membrane viscoelasticity. Their variation was investigated in this study after rabbits were radiated with 60Co. With a new ektacytometer, we measured the small deformation index (DId) and the half-time of deformation relaxation (t0.5) of RBC in flow field then we calculated RBC membrane shear elastic modulus and membrane viscosity. We found that the value of RBC membrane shear elastic modulus and membrane viscosity continuously increased from 0 to 16th day then continuously decreased and tended to be stable on 60th day or so. The reason may lie in the variation of proportion of new and old RBC in blood and variation of microconformation of RBC membrane after rabbits were radiated with 60Co.

Animals↗
PubMed2001

Effect of scopoletin on PC3 cell proliferation and apoptosis.

AIM: To investigate the effect of scopoletin on cell proliferation and apoptosis of PC3 cells. METHODS: Cell growth curve, MTT assay, and acid phosphatase activity (ACP) were used to determine cell proliferation. Coomassie brilliant blue assay was used to measure the content of protein in cells. Light microscope, transmission electronmicroscope, and fluorescence microscope were used to observe scopoletin-induced morphological changes. Apoptosis rate and cell cycle distribution were determined by flow cytometry. RESULTS: The IC50 of scopoletin for inhibiting PC3, PAA, and Hela cell proliferation was (157 +/- 25), (154 +/- 51), and (294 +/- 100) mg/L, respectively. Scopoletin induced a marked time- and concentration-dependent inhibition of PC3 cell proliferation. Scopoletin reduced the protein content and decreased the ACP level in PC3 cells in a concentration-dependent manner. Cells treated by scopoletin showed typical morphologic changes of apoptosis by light microscope, fluorescence microscope, and transmission electronmicroscope. Apoptosis rate was 0.3 %, 2.1 %, 9.3 % and 35 % for scopoletin 0, 100, 200, and 400 mg/L, respectively, and cells in G2 phase decreased markedly after being treated with scopoletin. CONCLUSION: Scopoletin inhibited PC3 proliferation by inducing apoptosis of PC3 cells.

Apoptosis↗
PubMed2001

[Detection of HPV in human esophageal cancer in high-incidence area and its correlation with p53 expression].

OBJECTIVE: To investigate the association of HPV with the development of esophageal cancer (EC) in a high-incidence area of EC and to elucidate its correlation with p53 overexpression. METHODS: Thirty EC specimens were collected from Anyang, Henan. Four pairs of primers were designed to perform in situ hybridization (ISH) and in situ PCR(ISPCR). Immunohistochemical staining was used to detect p53. RESULTS: HPV L1, HPV-16-E6 and HPV-16-E7 was detected in 10.0%, 60.0% and 63.3% of the EC samples, respectively. The detection rate of HPV-18-E6 was low(6.7%) and no EBV was detected. Overexpression of p53 was identified in 73.3% EC. With ISH or ISPCR, HPV-16-E6 was positive in 53.3% of EC. CONCLUSION: The low detection rate of HPV L1 and high detection rate of HPV-16-E6 and E7 genes suggest that HPV may be partially lost when integrating into tumor cell genome, while E6 and E7 genes are intact. The results support a role of HPV-16 in the pathogenesis of EC in high incidence area. Although p53 mutation takes an important part in tumor pathogenesis, it is not consistent with the HPV existence in the EC cells.

Esophageal Neoplasms↗
PubMed2001

Effect of 60Co irradiation on characteristics of hemorheology in rabbits.

A high-dose (7 Gy) whole-body 60Co irradiation for a short period caused disturbances of hematopoietic function. A decrease in the hematocrit of the circulating blood lasted for about 15 days, thus forming an anemic animal model. We studied the influence of high-dose 60Co irradiation on hemorheologic parameters: percentage of reticulocytes, RBC deformability, sedimentation rate and plasma fibrinogen concentration in the rabbit. It was found that the plasma fibrinogen concentration increased to twice more than control level and that percentage of reticulocytes in circulation disappeared immediately after irradiation. The deformation index of RBCs in shear flow decreased from a value of 58% down to a value of 42% in the first two weeks and gradually returned to control levels about 40 days after 60Co irradiation. Our results showed that a short period of high-dose 60Co irradiation caused severe and relatively long-lasting damage of hematopoietic system in animals' body.

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

[Nested case-control study on the risk factors of colorectal cancer].

OBJECTIVE: To investigate the risk factors of colorectal cancer. METHODS: A nested case-control study was conducted based on a cohort of 64,693 subjects in Jiashan county, Zhejiang, China. One hundred and ninety-six cases of colorectal cancer were detected during a follow-up program for 10 years. Nine hundred and eighty non-colorectal cancer subjects were randomly selected from the cohort as controls. Univariate analysis and mutivariate non-conditional logistic regression were used to analyse associations between the exposure factors and colorectal cancer. RESULTS: The age of case group was significantly older than that of the control group. Moreover, the age at diagnose of colon cancer was significantly older than that of the rectal cancer. Other than age, the final regression model showed that mucous blood stool history and colon polyp history were significantly associated with colon cancer (OR = 2.961, 95% CI:1.202-7.298 and 8.941, 95% CI:1.820-43.926, respectively) while mixed sources of drinking water was found to be associated with rectal cancer with a OR value of 1.823 (95% CI:1.024-3.247). CONCLUSION: The risk factors of colon cancer were different from that of the rectal cancer. Age was an important factor influencing the incidence of both colon cancer and rectal cancer. Mucous blood stool history and colon polyp history were associated with colon cancer, while drinking mixed water was closely associated with rectal cancer.

Adult↗
PubMed2001

[Meta-analysis of risk factors on lung cancer in non-smoking Chinese female].

OBJECTIVE: To evaluate the risk factors of lung cancer in non-smoking Chinese women. METHODS: The results of 7 case-control studies from 1990 to 1999 were analyzed by Meta-analysis method in this study. The cumulative cases and controls were 1 115 and 1 520, respectively. Der Simonian and Nan Laid model were applied to process data. RESULTS: The pools OR values of family history of lung cancer, personal history of non-neoplastic lung disease, cooking oil fume pollution, coal pollution and exposure to environmental tobacco smoking (ETS) were 2.87, 2.79, 2.52, 1.42 and 1.64 respectively. CONCLUSION: Family history of lung cancer and personal history of non-neoplastic lung disease might serve as the most important risk factors of female lung cancer in China. There appeared also significantly positive relationship between female lung cancer and the degree of cooking oil fume pollution or pollution of coal burning. The effect on lung cancer of exposure to ETS was uncertain in this study which calls for further investigation. Bias and confounding factors were also discussed in this study.

Air Pollution, Indoor↗
PubMed2001

[A comparative study on sterols of ethanol extract and water extract from Hericium erinaceus].

OBJECTIVE: To study the pharmaceutic chemical basis of the different medicinal effects, and to compare and analyze the sterols in Hericium erinaceus mycelia and its ethanol extract, water extract derived from solid fermented mycelia. METHOD: The components of Hericium erinaceus mycelia and two kinds of extract were compared with some biochemical methods such as GC, RP-HPLC, etc. Sterol composition in Hericium erinaceus mycelia was determined by using GC-mass spectrometry. RESULTS: The content of crude polysaccharide, water-soluble protein and fatty acid of ethanol extract showed no obvious advantage over its water extract. However, there was significant difference between two kinds of extract in the content of sterols. And ergostane derivatives, beta-sitosterol and C28 sterol with four bonds were detected as the major sterols in Hericium erinaceus mycelia, among which ergosterol was the principal sterol. CONCLUSION: Sterols in Hericium erinaceus exist mainly in ethanol extract. And three sterols are found for the first time from Hericium erinaceus, which are ergostane derivatives, beta-sitosterol and C28 sterol with four bonds.

Basidiomycota↗
PubMed2001

[Analysis of tendency of false and inferior species from Chinese medicinal materials markets].

OBJECTIVE: To offer information on the supervision by analysing the change of origin of false and inferior species from Chinese medicinal materials (CMM) markets. METHOD: 750 cases false and inferior species from Hubei province were compared classifiedly. RESULTS: In recent ten years, distributive characteristics of false and inferior species from CMM markets is as follows. First, false and inferior species from prepared medicinal herb increase, so do with man-made adulteration and poisonous species. Second, false and inferior species increase in rural area, country fairs, individual clinics and medicine booths. Last, extracted products are sold and used as certified products. CONCLUSION: CMM country fairs, outlying rural area, individual clinics and private medicine booths are the center of further supervision hereafter.

Consumer Product Safety↗