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Biomedical subjects

W Zheng

Publications and source records attributed to W Zheng.

At least 217 records · Page 12Linked to original sources
PubMed1997

Body mass index and the risk of cancers of the gastric cardia and distal stomach in Shanghai, China.

The divergent incidence patterns of gastric cardia and distal stomach cancers suggest different etiologies. Although obesity has recently been linked to cardia cancer in Western populations, its association with distal stomach cancer remains unclear. This study examined the relation of anthropometric measurements to risk by subsites of stomach cancer in a Chinese population. We identified 1124 population-based cases of stomach cancer, ages 20-69 years, newly diagnosed between December 1988 and November 1989 in Shanghai, China. Controls (n = 1451) were randomly selected from permanent Shanghai residents and frequency-matched to cases by age and sex. Information on demographic characteristics, height and weight, diet, smoking, and other exposures was obtained by trained interviewers in person. The body mass index (BMI) was calculated as weight in kilograms divided by height in square meters and categorized into quartiles based on the distribution among controls. Odds ratios and 95% confidence intervals were estimated using logistic regression models, simultaneously adjusting for age, education, income, cigarette smoking (men only), alcohol drinking (men only), intake of total calories, and chronic gastric diseases. For gastric cardia cancer, the odds ratios among men were 1.4, 1.5, and 3.0 in the second, third, and fourth quartiles of usual BMI (P for trend, < 0.01). Among women, elevated risks also were associated with excess weight, but the gradient in risk was not smooth. Risk patterns for usual body weight, maximum BMI, and minimum BMI were similar to those found for usual BMI. For distal stomach cancer, no association with usual BMI was observed among men, but a slightly elevated risk was seen among women. Our observations in China support recent findings in Western populations that obesity contributes to the risk of gastric cardia cancer, especially among men.

Adult↗
PubMed1997

Prior immunity-related medical conditions and oesophageal cancer risk: a population-based case-control study in Shanghai.

To investigate the role of immunity-related medical conditions in the aetiology of oesophageal cancer, data were analysed from a population-based case-control study, conducted in Shanghai during 1992-93. Information on histories of selected autoimmune diseases and allergic conditions was obtained from 163 incident cases of oesophageal cancer and 275 age- and sex-matched controls through personal interviews using a structured questionnaire. A significant 2.4-fold excess risk (95% CI, 1.3-4.4) of oesophageal cancer was associated with a history of autoimmune diseases after adjustment for age and sex. In contrast, a history of allergy was associated with a reduced risk (adjusted OR = 0.6, 95% CI = 0.4-0.9). The risk was also reduced 30-40% among individuals who reported having a moderate or strong skin reaction to mosquito bites. This study suggests that host immune function may be involved in the aetiology of oesophageal cancer. Further investigations into the mechanism of these observed associations are warranted.

Adult↗
PubMed1997

A new approach to protein fold recognition based on Delaunay tessellation of protein structure.

We propose new algorithms for sequence-structure compatibility (fold recognition) searches in multi-dimensional sequence-structure space. Individual amino acid residues in protein structures are represented by their C alpha atoms; thus each protein is described as a collection of points in three-dimensional space. Delaunay tessellation of a protein generates an aggregate of space-filling, irregular tetrahedra, or Delaunay simplices. Statistical analysis of quadruplet residue compositions of all Delaunay simplices in a representative dataset of protein structures leads to a novel four body contact residue potential expressed as log likelihood factor q. The q factors are calculated for native 20 letter amino acid alphabet and several reduced alphabets. Two sequence-structure compatibility functions are computed as (i) the sum of q factors for all Delaunay simplices in a given protein, or (ii) 3D-1D Delaunay tessellation profiles where the individual residue profile value is calculated as the sum of q factors for all simplices that share this vertex residue. Both threading functions have been implemented in structure-recognizes-sequence and sequence-recognizes-structure protocols for protein fold recognition. We find that both profile and total score based threading functions can distinguish both the native fold from incorrect folds for a sequence, and the native sequence from non-native sequences for a fold.

Amino Acid Sequence↗
PubMed1997

Smoking, alcohol, coffee, and tea intake and incidence of cancer of the exocrine pancreas: the Iowa Women's Health Study.

To assess the relationship of smoking and coffee, tea, and alcohol intake to the risk of cancer of the exocrine pancreas, analyses were performed using data from a prospective cohort study of 33,976 postmenopausal Iowa women who responded to a mailed questionnaire in 1986 and were followed through 1994 for cancer incidence and total mortality. At baseline, information on cigarette smoking, consumption of tea, coffee, and alcoholic beverages, and other dietary and lifestyle factors was obtained. Age-adjusted relative risks of pancreatic cancer (n = 66 cases) showed a dose-response association with smoking. Those with fewer than 20 pack-years and those with 20 or more pack-years of smoking exposure were 1.14 (95% confidence interval, 0.53-2.45) and 1.92 (95% confidence interval, 1.12-2.30) times more likely, respectively, to develop pancreatic cancer than were nonsmokers. Current smokers were twice as likely as were nonsmokers to develop pancreatic cancer. Relative risks of pancreatic cancer increased with the amount of alcohol consumed (Ptrend = 0.11) after adjustment for age, smoking status, and pack-years of smoking. Relative risks of pancreatic cancer according to alcoholic beverage intake were as strong among never-smokers as they were in the total cohort. After the data were adjusted for age, smoking status, and pack-years of smoking, there was a statistically significant 2-fold (95% confidence interval, 1.08-4.30) elevated risk of pancreatic cancer for those who drank > 17.5 cups of coffee per week, compared to those who consumed < 7 cups/week; among never-smokers, the relative risks across coffee intake categories were still positive but were attenuated somewhat (P trend = 0.17). Tea intake was not related to cancer incidence. In summary, these findings provide evidence of an association of both alcoholic beverage and coffee consumption with pancreatic cancer incidence that is independent of age and cigarette smoking.

Age Factors↗
PubMed1997

[Clinical analysis of spontaneous perforation of abdominal viscera in patients with severe viral hepatitis].

Eight out of 246 patients with severe viral hepatitis were complicated with spontaneous abdominal viscera perforation. The eight patients all had serious digestive symptoms, orange green colour in skin, swollen abdomen with ascites, abdominal pain. All cases were diagnosed by liver function examination, colour ultrasonography, x-ray examination, abdominal puncture and one case by operation. Among these 8 cases, 3 cases had perfornation of stomach, 3 cases had perforation of gall bladder and 2 cases had perforation of small intestine. Though emergancy treatment had been applied, only one case was saved.

Adult↗
PubMed1996

Identification of nonconserved amino acids in the AT1 receptor which comprise a general binding site for biphenylimidazole antagonists.

Mutational analysis based on pharmacological differences between mammalian and amphibian angiotensin II receptors (AT receptors) previously led to construction of a mutant receptor that gained > 25000-fold affinity for the biphenylimidazole, Losartan. This variant frog receptor also bound with high affinity other nonpeptides in the biphenylimidazole chemical class according to the following rank order of potency (expressed in Fmut values=mutant IC50/rAT1b IC50): Losartan, 0.91; L-162,389, 1.0; L-163,491, 1.9; L-158,809, 3.5; L-163,017, 3.9; SC-51,316, 3.9. In contrast, the imidazoleacrylic acids, SKF-108,566 (Fmut= 160) and SB-203,220 (Fmut = 170), bound with markedly less affinity. Thus, nonconserved residues determining the molecular requirements for biphenylimidazole recognition are conserved in general, but are not identical to nonconserved residues necessary for high affinity binding of imidazoleacrylic acids.

Amino Acid Sequence↗
PubMed1996

Diet and other risk factors for cancer of the salivary glands:a population-based case-control study.

A population-based case-control study of cancer of the salivary glands, involving interviews of 41 incident cases and 414 controls, was conducted in Shanghai. After adjustment for other risk factors, occupational exposure to silica dust was linked to a 2.5-fold increased risk of salivary-gland cancer. The risk was also significantly elevated among individuals who reported ever using kerosene as cooking fuel or having a prior history of head X-ray examinations. Dietary analyses revealed a significant protective effect of consumption of dark-yellow vegetables or liver, with about 70% reduced risk of salivary-gland cancer among individuals in the highest intake group of these foods. Our findings are consistent with previous observations on a possible role of environmental exposure and radiation in the etiology of salivary-gland cancer, and suggest that dietary factors may contribute to the development of this malignancy.

Adult↗
PubMed1996

Intake of vitamins A, C, and E and postmenopausal breast cancer. The Iowa Women's Health Study.

The association between dietary antioxidant vitamin intake and the risk of breast cancer was examined in a prospective study of 34,387 postmenopausal women in Iowa. Intakes of vitamins A, C, and E and of retinol and carotenoids were assessed in 1986 by mailed semiquantitative food frequency questionnaire. Through December 31, 1992, 879 incident breast cancer cases occurred in this cohort. There was little suggestion that breast cancer risk was associated with differences in intake of these vitamins. For example, from the lowest to highest total vitamin A intake categorized by quintiles, the age-adjusted relative risks of breast cancer were 1.0, 0.95, 1.17, 1.20, and 0.90 (p trend = 0.92). Similarly unremarkable relative risk patterns were seen for the intakes of vitamins C and E and of retinol and carotenoids. These findings were not altered after adjustment for breast cancer risk factors or in analyses confined to women who reported no supplemental vitamin intake. Exclusion of cases that occurred in the first 2 years of follow-up, under the assumption that women may have increased intake of these vitamins in response to preclinical symptoms of breast cancer, did not suggest an inverse association of these vitamins with the risk of breast cancer. Women who reported consuming at least 500 mg/day of supplemental vitamin C had a relative risk of breast cancer of 0.79 compared with women who did not take supplemental vitamin C, and women who reported consuming more than 10,000 IU/day of vitamin A had a corresponding relative risk of 0.73. However, these relative risks were not statistically significant. These results provide little evidence that intake of these vitamins is associated with breast cancer risk.

Aged↗
PubMed1996

Tea consumption and cancer incidence in a prospective cohort study of postmenopausal women.

Tea has consistently been shown to inhibit the occurrence of tumors in experimental animals. The evidence for such a beneficial effect in humans, however, is limited. The authors examined the association between non-herbal tea consumption and cancer incidence in a prospective cohort study of 35,369 postmenopausal Iowa women. In this cohort, information on the frequency of tea drinking and other dietary and lifestyle factors was collected by mailed survey in 1986. After 8 years of follow-up, 2,936 incident non-skin cancer cases were ascertained in this cohort through the State Health Registry of Iowa. Proportional hazards regressions were used to derive adjusted relative risks and 95% confidence intervals for the association between tea consumption and cancer incidence. After controlling for confounding factors, the authors found that regular tea consumption was related to a slight, but not statistically significant, reduced incidence of all cancers combined. Inverse associations with increasing frequency of tea drinking were seen for cancers of the digestive tract (p for trend, 0.04) and the urinary tract (p for trend, 0.02). For women who reported drinking > or = 2 cups (474 ml) of tea per day, compared with those who never or occasionally drank tea, the relative risk for digestive tract cancers was 0.68 (95% confidence interval (CI) 0.47-0.98) and for urinary tract cancers, 0.40 (95% CI 0.16-0.98). Similar inverse associations were seen for specific digestive and urinary tract cancers, although site-specific analyses were not statistically significant. No appreciable association of tea drinking was found with melanoma, non-Hodgkin's lymphoma, or cancers of the pancreas, lung, breast, uterine corpus, or ovary. This study suggests that tea, one of the most popular beverages consumed worldwide, may protect against some cancers in postmenopausal women.

Aged↗
PubMed1996

The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China.

BACKGROUND: The divergent incidence patterns of gastric cardia and distal stomach cancer may suggest different etiologies. This study examined the role of cigarette smoking, alcohol drinking, and green tea consumption as risk factors for carcinoma by anatomic subsite of stomach. METHODS: Newly-diagnosed stomach carcinoma patients (n = 1124) and frequency-matched population controls (n = 1451) were interviewed in person. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. RESULTS: Excess risks associated with cigarette smoking and alcohol consumption were observed largely among men. The adjusted ORs for all stomach cancer combined were 1.35 (CI: 1.06-1.71) for current smokers, and 1.26 (CI: 0.86-1.84) for ex-smokers. For tumors of the distal stomach, statistically significant positive dose-response trends were found for the number of cigarettes smoked per day, the duration and pack-years of smoking, and inverse trends for years of stopped smoking. For tumors of the gastric cardia, however, a monotonic association was found only for the number of cigarettes smoked per day (P=0.06). Alcohol consumption was not related to the risk of cardia cancer, while a moderate excess risk of distal stomach cancer (OR: 1.55; CI: 1.07-2.26) was observed among heavy alcohol drinkers. Green tea drinking was inversely associated with risk of stomach cancer arising from either subsite, with ORs of 0.77 (CI: 0.52-1.13) among female heavy drinkers, and 0.76 (CI: 0.55-1.27) among male heavy drinkers. CONCLUSIONS: Our findings provide further evidence that cigarette smoking and, possibly, alcohol consumption increase the risk of stomach carcinoma, notably of the distal segment. An inverse association with green tea drinking was also observed.

Adult↗
PubMed1996

Diet and risk of non-Hodgkin lymphoma in older women.

OBJECTIVE: To test whether high dietary intakes of fat, protein, and milk are associated with the development of non-Hodgkin lymphoma in older women. DESIGN: Prospective cohort study with a 7-year follow-up period. SETTING: General community. PARTICIPANTS: Sample of 35 156 Iowa women aged 55 to 69 years with no prior history of cancer who returned the 1986 baseline questionnaire. MAIN OUTCOME MEASURE: Non-Hodgkin lymphoma (104 incident cases). MAIN RESULTS: After controlling for age, marital status, residence, total energy intake, and transfusion history, the relative risks (RRs) for the highest tertile of intake compared with the lowest were 2.00 (95% confidence interval [CI], 1.21-3.30; P for trend = .01) for animal fat, 1.69 (95% CI, 1.07-2.67; P for trend = .02) for saturated fat, and 1.90 (95% CI, 1.18-3.04; P for trend = .01) for monounsaturated fat, and there was no association with vegetable fat or polyunsaturated fat. Greater intake of animal protein (RR = 1.52; 95% CI, 0.94-2.44; P for trend = .08), but not vegetable protein, was associated with elevated risk, and this was mainly explained by greater consumption of red meat (RR = 1.98; 95% CI, 1.13-3.47; P for trend = .02) and hamburger in particular (RR = 2.35; 95% CI, 1.23-4.48; P for trend = .02). Milk and dairy product consumption were not associated with elevated risk. There was also a decreased risk of non-Hodgkin lymphoma with greater consumption of fruits (RR = 0.64; 95% CI, 0.40-1.05; P for trend = .07). CONCLUSIONS: A high-meat diet and a high intake of fat from animal sources is associated with an increased risk of non-Hodgkin lymphoma in older women.

Aged↗
PubMed1996

Segregation analysis of breast cancer: a comparison of type-dependent age-at-onset versus type-dependent susceptibility models.

Most segregation analyses of breast cancer susceptibility have modeled the effect of the major gene on the age-at-onset distribution. However, in families linked to BRCA1 or BRCA2, there is wide variation in the age-at-onset among gene carriers. We performed a segregation analysis of 544 Minnesota breast cancer families using models which parameterized the putative major gene effect in two ways: earlier age-at-onset, with a common level of susceptibility (model I), and greater susceptibility, with a common mean age-at-onset (model II). Five hypothetical modes of transmission and an unrestricted general hypothesis were fitted to the data. Twice the difference between the log(e) likelihood for the data under the specified hypothesis (recessive, no major gene, etc.) and the log(e) likelihood under the general hypothesis is distributed asymptotically as a chi-square statistic with the degrees of freedom equal to the difference in the number of parameters estimated. This difference was compared to the critical value for the chi-square distribution to assess goodness-of-fit. Under model I, both Mendelian and non-Mendelian hypotheses were rejected. When model II was used, the non-Mendelian hypotheses were rejected whereas all Mendelian hypotheses were not. Mendelian recessive inheritance of a common allele (qA = 0.11) with a high penetrance (87%) provided the best fit to the data. We then stratified the families into two subsets based on the age at diagnosis of the proband [< or = 55 years (n = 265) versus > 55 years (n = 279)]; there was no evidence of heterogeneity under either model (I or II). These data suggest that, in some breast cancer families, the effect of the putative susceptibility gene is better represented as increasing overall susceptibility to breast cancer rather than as a shift in the age-at-onset distribution.

Adult↗
PubMed1996

p53 overexpression and bcl-2 persistence in endometrial carcinoma: comparison of papillary serous and endometrioid subtypes.

Forty-two cases, including 21 uterine papillary serous carcinomas (UPSC) and 21 age-, nuclear-grade-, and clinical-stage-matched uterine endometrioid carcinomas (UEC), were studied immunohistochemically for p53 and bcl-2 in archival paraffin-embedded tissue. Compared to UEC (28.6% positive), UPSC (71.4% positive) had a significantly higher frequency of p53 overexpression (P = 0.005); furthermore, in a clinical-stage-matched fashion, a higher frequency of p53 overexpression was found in early-stage cases (P = 0.032), but not in late-stage cases. In a nuclear-grade-matched comparison, no statistical difference in p53 overexpression was identified between the two subtypes, although UPSC had stronger p53 immunoreactivity than UEC. Of UPSC, no difference in p53 overexpression was detected between tumors of early and late stages; additionally, in 5 cases, there was an abrupt transition from nonstaining morphologically benign glands to uniformly positive p53 nuclear staining in regions of intraepithelial carcinoma. Conversely, in UEC, there was a significant difference in p53 immunostaining between tumors of early and late stages (P = 0.01); no case had an abrupt transition for p53 immunostaining. For bcl-2 immunostaining, UEC had a significantly higher immunohistochemical staining score than did UPSC (P = 0.0002). In general, the staining intensity of bcl-2 diminished progressively from proliferative phase and hyperplastic endometrium to UEC and then to UPSC, with 3 of 21 (14.3%) UPSC being negative. These results suggest that p53 alteration may be an early event in the development of UPSC and may be related to its clinical aggressiveness, while it is a late event in UEC. Early detection of p53 nuclear accumulation may help to identify precursor lesions of UPSC. bcl-2 persistence is frequently associated with endometrial carcinoma, and failure to inactivate bcl-2 expression probably is related to the development of endometrial carcinoma.

Aged↗
PubMed1996

Chronic lead exposure alters transthyretin concentration in rat cerebrospinal fluid: the role of the choroid plexus.

The choroid plexus, which is responsible for the maintenance of the biochemical milieu of the cerebrospinal fluid (CSF), avidly sequesters Pb. In order to test the hypothesis that chronic Pb exposure may impair choroid plexus function, male weanling Sprague-Dawley rats were exposed to Pb in drinking water at doses of 0, 50, or 250 micrograms Pb/ml (as Pb acetate) for 30, 60, or 90 days. The function of the choroid plexus was assessed as reflected by CSF concentrations of transthyretin (TTR, a major CSF protein manufactured by brain choroid plexus) and CSF essential metal ions (Ca2+, Mg2+, K+, and Na+). TTR concentrations were determined by radioimmunoassay using a monospecific rabbit anti-rat TTR polyclonal antibody, and CSF metal ions analyzed by flame atomic absorption spectrophotometry. Two-way ANOVA of CSF TTR concentrations revealed highly significant dose (p < 0.0001), time (p < 0.0223), and dose-by-time effects (p < 0.0379). Moreover, the percentage of reduction of CSF TTR was directly correlated with Pb concentrations in the choroid plexus (r = 0.703, p < 0.05). Pb exposure significantly increased CSF concentrations of Mg2+, but did not markedly altered CSF concentrations of Ca2+, K+, and Na+. Histopathologic examination under the light microscope did not show distinct alterations of plexus structure in Pb-treated rats. Since TTR is responsible for transport of thyroid hormones to the developing brain, we postulate that the depression of choroid plexus TTR production (and/or secretion) by Pb may impair brain development in young animals by depriving the CNS of thyroid hormones.

Administration, Oral↗
PubMed1996

KSHV antibodies among Americans, Italians and Ugandans with and without Kaposi's sarcoma.

A major controversy regarding Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8) is whether or not it is a ubiquitous infection of humans. Immunoassays based on KSHV- and Epstein-Barr virus (EBV)-coinfected cell lines show that most US AIDS-KS patients have specific antibodies to KSHV-related antigens. We have developed a sensitive indirect immunofluorescence assay (IFA) based on an EBV-negative, KSHV-infected cell line, BCP-1. When we used this IFA assay, KSHV-related antibodies were found in 71-88% of serum samples from US, Italian and Ugandan AIDS-KS patients, as well as all serum samples examined from HIV-seronegative KS patients. Although none of the US blood donors examined were KSHV seropositive by IFA, intermediate and high seroprevalence rates were found in Italian and Ugandan control populations. Antibody kinetics showed that more than half of the AIDS-KS patients who were examined IgG-seroconverted before KS development, and antibody levels did not decline after seroconversion. For these patients, seropositivity rates increased linearly with time, suggesting that the rate of infection was constant and that the risk of developing KS once infected with KSHV is not highly dependent on the duration of infection. These data strongly suggest that KSHV is not ubiquitous in most populations and that the virus may be under strict immunologic control in healthy KSHV-infected persons.

AIDS-Related Opportunistic Infections↗
PubMed1996

Borderline papillary serous tumour of the fallopian tube.

We report a case of borderline papillary serous tumor of the fallopian tube in a 31-year-old woman. The tumor was characterized by the formation of papillary projections with focally prominent epithelial stratification and atypia. The histologic features of the tumor were largely similar to a borderline serous tumor of the ovary. Two years after initial presentation, the patient underwent in vitro fertilization and carried the ensuing pregnancy to term. There is no evidence of disease nearly 6 years after presentation, which suggests that these extremely uncommon tumors can be managed conservatively.

Adult↗
PubMed1996

Cancer incidence among women living on farms: findings from the Iowa Women's Health Study.

The purpose of this study was to determine whether site-specific cancer incidence in women residing on farms is different from those residing elsewhere. A large population-based cohort of Iowa women 55 to 69 years of age reported in a questionnaire whether or not they lived on a farm. Linkage to a statewide registry identified cancers occurring between 1986 and 1992. Age-adjusted relative risks (RR; 95% confidence interval) of all cancers (RR = 0.84; 0.76 to 0.92), lung cancer (RR = 0.32; 0.20 to 0.50), and bladder cancer (RR = 0.33; 0.12 to 0.92) were reduced significantly in farm residents, compared with non-farm residents. These findings were largely accounted for by other cancer risk factors, most importantly, cigarette smoking. The multivariate adjusted risk of non-Hodgkin's lymphoma was elevated in farm residents for all lymphoma sites (RR = 1.52; 0.96 to 2.39) and lymph node sites (RR = 1.89; 1.13 to 3.18). Reduced risks of smoking-related cancers and elevated risk of non-Hodgkin's lymphoma among farm residents have been reported previously, primarily in men. Our findings suggest that farm women may be exposed to some of the same factors that determine cancer risk in male farmers.

Age Factors↗