Biomedical subjects

C C Hsieh

Publications and source records attributed to C C Hsieh.

At least 163 records · Page 9Linked to original sources

PubMed1994

Some statistical considerations in the analysis of case-control studies when the exposure variables are continuous measurements.

This paper focuses on some statistical considerations in the estimation of dose-response in case-control studies when the exposure variables are continuous measurements. The first point is that the effects of differential variability in the exposure distributions over cases and controls cannot be differentiated from a true quadratic risk model. The second point is that when dealing with variables where zero denotes no exposure, it is important to treat the unexposed subjects separately from those who were exposed. Failure to do so can lead to differential variability among cases and controls and the resulting confounding with a quadratic risk model. Both of these points are illustrated by an example.

Case-Control Studies↗

PubMed1994

Handedness, age at menarche, and age at menopause.

OBJECTIVE: To investigate the relation between handedness and age at menarche or age at menopause, as both handedness and reproductive variables have been suggested to be influenced by the intrauterine endocrine environment. METHODS: Self-reported information on handedness, age at menarche, age at menopause, and other demographic and reproductive variables was recorded for 10,328 women still menstruating or in natural menopause. These women had been selected as controls in a multicenter case-control study of breast cancer conducted in the 1960s. Left-handedness (including ambidexterity) was modeled as the outcome variable through multiple logistic regression. RESULTS: After adjusting for center, age, menopausal status, age at menopause, years of schooling, and parity, there was no significant relation of handedness to age at menarche (odds ratio for each year delayed 1.01, 95% confidence interval [CI] 0.97-1.06) or age at menopause (odds ratio 1.00, 95% CI 0.98-1.02). CONCLUSION: These findings lend no support to the hypothesis that intrauterine endocrine variables associated with handedness also are related to reproductive variables.

Adolescent↗

PubMed1994

Erythrocyte Ca2+ pump is defective during sepsis.

Saturated Ca2+ extrusion rate through the Ca2+ pump of erythrocytes was determined by the cobalt-exposure method in normal subjects and septic patients. From 48 normal subjects, the value of Vmax of erythrocyte Ca2+ pump was 14.83 +/- 0.49 mmol/L cells/hr; from 29 sepsis patients, it was 9.49 +/- 0.59 mmol/L cels/hr, significantly (P < 0.001) lower than that from the erythrocytes of normal subjects. When the severity of sepsis was evaluated by the septic severity score (SSS), a significant correlation (P < 0.0001) was observed between the Vmax of Ca2+ pump and the patient's SSS, indicating that the inhibition of Ca2+ pump depended on the degree of the pathological development of sepsis. Since the ATP-dependent Ca2+ transport in rat liver plasma membrane is also reduced during the late stage of sepsis [Lau et al., Circ Shock 38:238-244, 1992], impairment of the activity of Ca2+ pump appears to have a general pathophysiological significance in the development of severe sepsis.

Adenosine Triphosphate↗

PubMed1994

Effects of DL-tetrahydropalmatine on motor activity and the brain monoamine concentration in rats.

Behavioral and biochemical methods were used in this study to investigate the effect of DL-THP on motor activity and the concentration of monoamines in rats. Experimental results indicated that DL-THP significantly decreased the motor activity of rats and showed a dose-response pattern; in addition, it produced rigidity at a higher dosage. DL-THP also enhanced the hypomotility induced by haloperidol, but reduced the hypermotility produced by apomorphine. Furthermore, DL-THP significantly decreased the concentration of norepinephrine (NE), dopamine (DA) in the cortex and brain stem at lower and higher dosages, and the concentration of serotonin (5-HT) in the cortex at higher dosages. DL-THP also increased the concentration of homovanillic acid (HVA) in the cortex and brain stem at lower and higher dosages, and the concentration of 5-hydroxyindole acetic acid (5-HIAA) in the cortex at higher dosages. These results suggest that the hypomotility produced by DL-THP may be due to the increase in the turnover rate of dopamine in the cortex and brain stem at lower and higher dosages, and of serotonin in the cortex at higher dosages.

Animals↗

PubMed1994

Comparison of physical properties of light-curing and self-curing dental impression materials.

A light-curing polyether urethane dimethacrylate impression material was recently developed. Its polymerization reaction is activated by intensified visible light; therefore, the on-demand set allows operators to work at their own pace. Furthermore, its constant viscosity provides a constant flow rate at the critical stages of taking impressions. The purposes of this study were to evaluate the physical properties and accuracy of this light-curing impression material and to compare it with those of self-curing impression materials currently used in our dental clinic. Physical properties such as strain in compression, compression set, dimensional stability, and tear strength of the impression materials were measured according to test methods stipulated in ADA Specification No. 19 for elastomeric impression materials. The template-coping method developed by Lewinstein and Craig was used to evaluate the accuracy of the impression materials. It was found that the strain in compression of the polyether urethane dimethacrylate was higher than that of the condensation silicones, but lower than that of the addition silicones. The compression set of the condensation silicones was more than that of the polyether urethane dimethacrylate, but much less than that of the polysulfides. The dimensional stability showed that all of the impression materials, except the polyether urethane dimethacrylate, had a negative dimensional change 24 hours after mixing. The sequence is: polysulfide < condensation silicone < addition silicone. The expansion rate of the light-curing material was measured under 0.07% one day after curing. The polyether urethane dimethacrylate had extraordinary tear resistance compared to the other impression materials.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗

PubMed1993

Risk of extrahepatic bileduct cancer after cholecystectomy.

The aetiology of cancer of the extrahepatic bile duct is unknown. Gallstones have been proposed to be a risk factor on the basis of ecological and epidemiological evidence. As gallstones are formed in the gallbladder, the occurrence of extrahepatic bileduct cancer in patients after cholecystectomy is of interest. All patients (62,734) who had had a cholecystectomy during 1965-1983 within the Uppsala Health Care Region, Sweden, were followed up to the end of 1987. Excluding the first year of follow-up, 23 cancers of the extrahepatic bileduct occurred vs 26.3 expected for a standardised incidence ratio (SIR) of 0.88 (95% confidence interval [CI] 0.56-1.31). 10 years or more after operation there was a greater reduction of risk (SIR = 0.27; 95% CI 0.06-0.80). Similar patterns were observed for men and women, and among patients who had undergone cholecystectomy only compared with those who had had their common bileducts explored. To assess surveillance bias the incidence of primary liver cancer was also analysed: SIR = 1.15; 95% CI 0.91-1.44 overall, and 10 years or more after cholecystectomy SIR = 0.98; 95% CI 0.66-1.40. This study shows a reduced risk of extrahepatic bileduct cancer 10 or more years after cholecystectomy, indicating that gallstones may be a cause of this cancer.

Bias↗

PubMed1993

Parity and hepatocellular carcinoma. A population-based study in Sweden.

The association between parity and hepatocellular carcinoma (HCC) was studied using a data-base generated by linking 2 Swedish nation-wide registries; the Cancer Registry and the Fertility Registry. Among women born between 1925 and 1960, 133 patients with HCC recorded in the Cancer Registry between 1958 and 1984 were compared with 665 age-matched controls. In this nested case-control study there was no positive association between parity, age at first birth or frequency of twinning on the one hand, and risk of HCC on the other. It appears that the positive association between parity and HCC previously reported is limited to cases of HCC caused by chronic infection with hepatitis B virus; these cases represent only a small fraction of HCC cases in Sweden.

Adult↗

PubMed1993

Reproductive variables, tobacco, ethanol, coffee and somatometry as risk factors for ovarian cancer.

A hospital-based case-control study of ovarian cancer was conducted in Athens from 1989 to 1991. The cases were 189 women, residents of Greater Athens and less than 75 years old, with histologically confirmed common malignant epithelial tumors of the ovary, operated in the 2 major cancer hospitals of the Greater Athens area. Controls were women residents of Greater Athens, less than 75 years old, who had never had cancer or had an ovary removed and who had visited patients hospitalized in the same wards as the ovarian cancer cases at the same time. The data were analyzed by modeling through multiple logistic regression. Statistically significant associations were found with induced menopause without oophorectomy [relative risk (RR) 0.17; 95% confidence interval (CI) 0.04 to 0.72], age at menopause (for an increment of 5 years RR 1.42; CI 1.00 to 2.01), hormone-replacement therapy (RR 5.73; CI 1.07 to 30.80), parity (RR 0.48; CI 0.24-0.96) and, marginally, age at first birth (for an increment of 5 years RR 1.30; CI 0.99 to 1.70). Non-significant but previously suggested or biologically plausible associations were noted with use of oral contraceptives (inverse), weight before onset of the disease (positive), and consumption of more than 2 glasses of alcoholic drinks per day (positive). There were no consistent associations with coffee, tobacco, moderate alcohol intake, broad occupational group, induced abortions, or age at menarche.

Adult↗

PubMed1993

Hair dyes, analgesics, tranquilizers and perineal talc application as risk factors for ovarian cancer.

In a hospital-based case-control study of ovarian cancer conducted in Athens (1989-1991), 189 women with histologically confirmed common malignant epithelial tumors of the ovary were compared with 200 hospital visitor controls. All interviews were conducted by personal interview in the 2 participating hospitals and the data were analyzed by modelling through logistic regression, controlling for demographic and reproductive variables. Tranquilizing and hypnotic drugs (mostly diazepam) were not associated with risk of ovarian cancer: the adjusted relative risk (RR) and 95% confidence interval (CI) were 0.96 (0.57 to 1.63), whereas use of analgesics (mostly salicylates) was associated with significantly reduced risk of the disease (RR 0.51; CI 0.26 to 1.02). There was no evidence that perineal application of talc was associated with increased risk (RR 1.05; CI 0.28 to 3.98) but the frequency of reporting talc use was low in the study population. There was a statistically significant (p for trend 0.007) and a dose-dependent association between hair dyeing and risk of ovarian cancer. Compared to never-users, women dyeing their hair up to 4 times per year had a relative risk of 1.74 (0.91 to 3.32) whereas those dyeing their hair 5 or more times per year had a relative risk of 2.16 (1.19 to 3.89).

Adult↗

PubMed1993

Diet and ovarian cancer: a case-control study in Greece.

In a hospital-based case-control study of common malignant epithelial tumors of the ovary, conducted in Athens (1989-1991), 189 cases were compared with 200 hospital visitor controls. Personal interviews were conducted in all cases and diet was ascertained through a semi-quantitative food frequency questionnaire. Nutrient intakes for individuals were estimated by multiplying the nutrient content of a typical portion size for each specified food item by the frequency at which the food was consumed per month and summing these estimates for all food items. Data were analyzed using logistic regression, controlling for non-dietary confounding factors, total energy intake and, among nutrients, mutual confounding influences. Adjusted odds ratios (rate ratios) for ovarian cancer, associated with particular nutritional variables, were expressed in terms of increments approximately equal to the standard deviations of (the residual of) the respective nutrients, on a daily basis. The adjusted odds ratios (and 95% confidence intervals) were 0.80 (0.65-0.99) for mono-unsaturated fat and 0.73 (0.61-0.87) for crude fiber. No substantial, statistically significant or consistent independent associations were noted for total energy, total protein, saturated fat, polyunsaturated fat, dietary cholesterol, total carbohydrates, sucrose, vitamin C, vitamin A, riboflavin or calcium. These associations, if causal, could explain to some extent the relatively low incidence of ovarian cancer in Greece and other Mediterranean countries as well as the increasing incidence trends noted in these countries during the last few decades.

Adult↗

PubMed1993

Parity and cancers of the gall bladder and the extrahepatic bile ducts.

The relation of parity and age at first birth to cancers of the gall bladder and extrahepatic bile ducts in women was studied using a database generated by linking 2 Swedish national registries; the Fertility Registry and the Cancer Registry. Among women born between 1925 and 1960, 257 cases of gall-bladder cancer recorded in the Cancer Registry between 1958 and 1984 were compared with 1,285 controls, age-matched to cases in a 5:1 ratio. In addition, 60 cases of extrahepatic-bile-duct cancer were matched with 300 controls. There was a positive association between number of live births and risk of gall-bladder cancer (p 0.06), but simultaneous consideration of parity and age at first birth revealed a more complex picture. Parity increases the risk for cancer of the gall bladder when the first birth occurs before the age of about 25 years, whereas parity associated with first birth after the age of about 30 years is associated with reduced risk for the disease. Thus, among parous women there is a highly significant inverse association of age at first birth with risk for gall-bladder cancer after adjustment for number of live births. Variable levels of pregnancy estrogens according to maternal age and variable effects of parity on non-pregnancy estrogens by age, may explain the observed pattern. The results on extrahepatic-bile-duct cancer, parity and age at first birth did not indicate the existence of an association in either direction.

Adult↗

PubMed1993

trans-activation of the alpha 1-acid glycoprotein gene acute phase responsive element by multiple isoforms of C/EBP and glucocorticoid receptor.

alpha 1-Acid glycoprotein (AGP) is a major acute phase protein synthesized primarily by the liver. The AGP gene is transcriptionally activated in hepatocytes during the acute phase response to bacterial lipopolysaccharide. In this study, we analyzed an acute phase responsive element (APRE) located between nucleotide residues -127 to -104 relative to the transcription initiation site of the mouse AGP gene. Binding studies show that several trans-acting factors interact with the APRE. Using monospecific antibodies we demonstrate that three isoforms of the CCAAT/enhancer-binding protein (C/EBP) family, namely C/EBP alpha, C/EBP beta, and C/EBP delta, bind to the APRE. Furthermore, with liver nuclear protein from control animals, C/EPB alpha is the predominant form that binds to the APRE, whereas with nuclear proteins from acute phase-induced animals, C/EBP alpha is replaced by C/EBP beta. The mechanism of activation of the AGP gene during the acute phase response appears to involve an exchange of C/EBP alpha by C/EBP beta. C/EBP delta does not play a role in this reaction. Interestingly, the C/EBP binding site of the APRE partially overlaps a functional glucocorticoid responsive element. We present evidence that both purified C/EBP alpha and glucocorticoid receptor bind strongly to the APRE. By site-specific mutation, we have identified the C/EBP and glucocorticoid receptor binding sites in the APRE. These mutants were used in expression vectors to demonstrate that both C/EBP and glucocorticoid receptor are essential for maximal response to interleukin-6 and dexamethasone. These results demonstrate that the APRE is a composite binding site for multiple factors that are responsible for the transcriptional control of the mouse AGP. Finally, functional analyses indicate that C/EBP alpha, C/EBP beta, and C/EBP delta are strong transcriptional trans-activators of the AGP APRE in hepatoma cells. These data suggest that the regulatory activity of the C/EBP with the APRE in the liver may require interactions with adjacent proteins.

Acute-Phase Reaction↗

PubMed1993

Breast cancer risk in mothers of multiple births.

Data from an international case-control study of breast cancer that was conducted in the 1960s were used to examine whether multiple births affect the risk of breast cancer in the mother. Among 2821 parous breast-cancer patients, 88 had had one or more multiple births, whereas among 8882 controls 247 had had one or more multiple births; the logistic-regression-adjusted odds ratio (OR) was 1.21, the 95% confidence interval (CI), 0.94 to 1.55. The OR was significantly elevated during the 15-year period following the latest multiple birth (1.76; CI, 1.12 to 2.75), but declined toward the null afterwards. A late first pregnancy imparted a substantially higher breast-cancer risk when it was multiple rather than singleton; the OR was 2.34 for a multiple and 1.48 for a singleton first pregnancy when the cutoff point was 30 years, and 4.58 and 1.57, respectively, when the cutoff point was 35 years. Since multiple pregnancies are characterized by higher levels of pregnancy estrogens, the results of this study would be compatible with the hypothesis that these hormones may be responsible for the transient increase in breast-cancer risk following a term pregnancy and, in particular, a multiple term pregnancy. The long-term reduction of breast-cancer risk is probably due to a different mechanism, most likely the terminal differentiation of susceptible mammary-gland cells.

Adult↗

PubMed1993

Tobacco, ethanol, coffee, pancreatitis, diabetes mellitus, and cholelithiasis as risk factors for pancreatic carcinoma.

A hospital-based case-control study of pancreatic cancer was conducted in Athens in 1991-92. One hundred and eighty-one patients operated on for cancer of the exocrine pancreas in eight teaching hospitals formed the case series, whereas hospital patient controls and hospital visitor controls formed two independent comparison series. Cases and controls were matched by hospital, gender, and age in a 1:1:1 ratio, and every matched triplet was interviewed in person by the same researcher. Results indicate that tobacco smoking increased the risk of pancreatic cancer, whereas neither coffee drinking nor consumption of alcoholic beverages were associated with the disease. Diabetes mellitus, cholelithiasis, and pancreatitis were associated positively with risk of pancreatic cancer, whereas allergic asthma was inversely (but not significantly) related to the disease. There was a suggestion that earlier age at menarche was associated with increased risk of pancreatic cancer and that parous women were at lower risk. No consistent associations were noted with respect to gastrectomy, other medical conditions or operations, birth order, height, weight, broad occupational groups, or other reproductive variables. The two comparison series were remarkably similar with respect to the whole spectrum of the study variables.

Adult↗

PubMed1993

Nutrient intake and cancer of the pancreas: a case-control study in Athens, Greece.

In a hospital-based case-control study of pancreatic cancer conducted in Athens (1991-92), 181 patients with histologically confirmed cancer of the exocrine pancreas were compared with hospital patient controls and hospital visitor controls, individually matched to the cases by hospital, age, gender, and interviewer in a 1:1:1 ratio. All interviews were conducted in person in the respective hospitals. Diet was ascertained through a semiquantitative food-frequency questionnaire. Nutrient intakes for individuals were estimated by multiplying the nutrient content of a selected typical portion-size for each specified food-item by the frequency that the food was used per month, and summing these estimates for all food items. Data were analyzed using conditional logistic regression, controlling for tobacco smoking and total energy intake as well as for mutual confounding influences among nutrients. Adjusted odds ratios (rate ratios) for pancreatic cancer, associated with particular nutritional variables, were expressed per increments approximately equal to the standard deviations of (the residual of) the respective nutrients, on a daily basis. The adjusted odds ratios (OR) and 95 percent confidence intervals (CI) compared with other patient and visitor controls respectively, were: for polyunsaturated fat, OR = 1.32 (CI = 1.07-1.63) and 1.21 (CI = 0.98-1.49); and for crude fibre, OR = 0.80 (CI = 0.64-1.00) and 0.65 (CI = 0.50-0.86). No substantial, statistically significant or consistent, independent associations were noted for total energy, total protein, total fat, saturated fat, monounsaturated fat, dietary cholesterol, total carbohydrates, sucrose, vitamin C, vitamin A, riboflavin, or calcium.

Ascorbic Acid↗

PubMed1993

Breast-feeding and maternal smoking in the etiology of Crohn's disease and ulcerative colitis in childhood.

Medical records concerning pediatric or adolescent patients first diagnosed with Crohn's disease or ulcerative colitis in two New York hospitals during a 5-year period (1986 to 1990) were abstracted, and information concerning sex, age, race, birthplace, sibship size, birth order, maternal age at birth, month of birth, duration of breast-feeding, and maternal smoking was recorded. Medical records of patients presenting at the respective pediatric gastroenterology departments immediately before or after the patients with inflammatory bowel disease were seen were also abstracted in order to generate a control series. Data concerning 68 patients with Crohn's disease, 39 patients with ulcerative colitis, and 202 control patients were analyzed through multiple logistic regression. Breast-feeding was negatively associated with Crohn's disease (P approximately 0.04) and ulcerative colitis (P approximately 0.07), with relative risk point estimates around 0.5 and with evidence of duration-dependent trends in both instances. There was no evidence of association of either disease with maternal age at birth, birth order, maternal smoking, or season of birth.

Adolescent↗

PubMed1993

Breast-feeding and breast cancer in the offspring.

The causation of breast cancer in certain strains of mice by a virus that can be transmitted vertically, through the milk produced during lactation, has led to the hypothesis that a similar phenomenon could exist in humans. There have been laboratory-based studies in humans suggesting that a virus may be involved in the etiology of female breast cancer although other investigations did not support this hypothesis. Descriptive data and epidemiologic evidence of ecologic nature do not indicate a role of lactation in the causation of human breast cancer, but the hypothesis has not been adequately assessed in analytic epidemiologic studies. A nested case-control study undertaken in Sweden to examine the role of prenatal factors on breast cancer risk in the offspring, allowed the evaluation of the importance of breast-feeding in the causation of this disease. Standardised records concerning women born at the Uppsala University Hospital from 1874 to 1954 were linked with invasive breast cancer incident cases, identified through their unique national registration number in the Swedish Cancer Registry during 1958-1990. For each case with breast cancer, the females born to the first three mothers admitted after the case's mother were selected as potential matching controls. Only controls living in Sweden and free from breast cancer until the time of diagnosis of breast cancer in the corresponding case were eventually included in the study. The analysis was based on 458 cases of breast cancer born in singleton pregnancies and 1,197 singleton age- and birth date-matched controls. Breast-feeding was not a significant or suggestive risk factor for breast cancer in the offspring; compared to women who at discharge were wholly or partly breastfed, women who as newborn were not breastfed had a relative risk of breast cancer of 0.97 with 95% confidence interval 0.44-2.17 (P = 0.95).

Breast Feeding↗

PubMed1993

Prevalence and characteristics of areca nut chewers among junior high school students in Changhua county, Taiwan.

Some studies indicate that betel quid and its ingredients chewing can produce cell mutagenicity and tumorigenicity. In Taiwan studies, betel quid chewing is the main cause of submucous fibrosis and oral cancer. Understanding the distribution and characteristics of the areca nut chewing population is one of the first steps in the effort to prevent these oral diseases. A stratified cluster random sample of 2442 junior high school students in Changhua county, Taiwan, were surveyed for the habit of areca nut chewing. Significantly more male students chewed areca nut than female students (9.2% vs 0.9%). The proportion of students who were chewing areca nuts increased with increasing (seventh to ninth) grades. Areca nut was used by junior high school students at a higher rate in village (rural) areas as compared to town (semi-urban) and city (urban) areas (6.4%, 3.7% and 3.0%, respectively). More students in the ordinary achievement classes were chewing areca nuts than those in the high achievement classes (8.4% vs 1.6%). Areca nut chewing students tended to have users in their families. Cigarette smoking and alcohol drinking were positively associated with areca nut chewing. More than half (53.6%) of the areca nut chewing students first experimented with this habit with a family member, most often the father or grandfather.

Adolescent↗