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PubMed1992

Relationships of desire for no more children and socioeconomic and demographic factors in Sri Lankan women.

Data from the 1982 Sri Lanka Contraceptive Prevalence Survey are used to identify women who wish to stop childbearing; they differ in socioeconomic status from their counterparts who want more children. Educated women are more likely to be motivated to cease childbearing than non-educated women; Christian or Sinhalese/Buddhist women are more willing to stop childbearing than Moor/Muslim or Tamil/Hindu women. The relationships between sex composition of existing children and women's fertility desires indicate that although moderate son preference exists it does not affect their contraceptive behaviour. Among those who want no more children, 15% are at risk of unwanted pregnancy because they do not practise contraception. Again better education and being Christian or Sinhalese/Buddhist reduced the risk of unwanted pregnancy. Women whose husbands disapproved of contraception had over four times higher risk of unwanted pregnancy than women whose husbands approved.

Adolescent↗
PubMed1992

Immunisation coverage in Lusaka, Zambia; implications of the social setting.

This paper develops a conceptual framework for examining the process of immunisation and explores the sociodemographic determinants of vaccination in Zambia. About 300 mothers with children under 3 years of age were interviewed in urban Lusaka. The analyses suggest that sociostructural, as well as cultural, processes influence the attrition process and immunisation programmes should focus on the uniqueness of each stage. In addition, programmes to improve women's education and to reduce male gender preferences are needed.

Child, Preschool↗
PubMed1999

Antecedents of the risk of recovery from DSM-III-R social phobia.

BACKGROUND: This study reports antecedents of recovery from DSM-III-R social phobia. METHODS: Retrospective data were obtained from 1116 individuals age 15 to 64 participating in a large population health survey in the province of Ontario, Canada RESULTS: Approximately 50% of the sample recovered from their illness. Survival analysis revealed a median length of illness of 25 years with peak periods of risk of recovery occurring between 30 and 45 years duration. Using discrete time multivariate hazard regression analysis, statistically significant predictors of recovery from social phobia included: childhood social contextual factors (one or no childhood siblings, a small town childhood place of residence), characteristics of the disorder (onset past the age of 7, less than three disorder symptoms), an absence of co-morbid health-related conditions and psychiatric disorders (chronic health problems and major depression), and the occurrence of co-morbid chronic health problems and major depression prior to the onset of the disorder. CONCLUSIONS: Our data indicate that social phobia in the general population is a chronic and unremittent disorder. Determinants of recovery are rooted in distal childhood circumstances, disorder attributes, and the physical and mental health status of individuals over the life course.

Adolescent↗
PubMedDate not supplied

Quantum molecular similarity. 3. QTMS descriptors.

Building on the ideas of a previous paper [part 1, J. Phys. Chem. A 1999, 103, 2883] we present a new molecular similarity method based on the topology of the electron density. This method is directly applicable to QSARs and is called quantum topological molecular similarity (QTMS). It has been tested for five sets of carboxylic systems including para- and meta-benzoic acid, para-phenylacetic acid, 4-X-bicyclo[2.2.2]octane-1-carboxylic acids, and polysubstituted benzoic acids. In combination with the partial least squares (PLS) procedure QTMS is able to produce excellent and statistically valid regressions. It is shown that QTMS avoids certain challenges of traditional Carbó-like similarity indices. Finally, QTMS is able to suggest a molecular fragment that contains the active center or the part of the molecule that is responsible for the QSAR.

Journal Article↗
PubMed2005

Prediction of global vapor-liquid equilibria for mixtures containing polar and associating components with improved renormalization group theory.

Our recently improved renormalization group (RG) theory is further reformulated within the context of density functional theory. To improve the theory for polar and associating fluids, an explicit and complete expression of the theory is derived in which the density fluctuation is expanded up to the third-order term instead of the original second-order term. A new predictive equation of state based on the first-order mean spherical approximation statistical associating fluid theory (FMSA-SAFT) and the newly improved RG theory is proposed for systems containing polar and associating fluids. The calculated results for both pure fluids and mixtures are in good agreement with experimental data both inside and outside the critical region. This work demonstrates that the RG theory incorporated with the solution of FMSA is a promising route for accurately describing the global phase behavior of complex fluids and mixtures.

Gases↗
PubMed1998

Inhibition of the conjugation of PABA with glycine in vitro by sulfamoyl benzoic acids, sulfonamides, and penicillins and its relation to tubular secretion.

Elimination of drug molecules via tubular secretion is an important pharmacokinetic parameter especially for oral dosage forms where an extremely short half-life would prevent their application. We have studied the inhibition in vitro of the glycination of p-aminobenzoic acid (PABA) using rat liver microsomal preparations. The I50 values, the concentration of the inhibitor that leads to 50% inhibition of glycine conjugation of PABA as compared to the control, have been determined for sulfamoyl benzoic acids, sulfonamides, and penicillins. Statistically significant regression equations were derived explaining the observed variation in I50 values as a function of lipophilicity and steric bulk of the substituents for the combined set of sulfamoyl benzoic acids and sulfonamides (n = 33). For the penicillins studied, only steric effects seem to be important for the explanation of the I50 values. Finally, regression analysis and the use of neural networks allowed the classification of compounds by their in vitro I50 values as being tubular secreted or not. Therefore, it can be concluded that the inhibition in vitro of the glycine conjugation of PABA is a useful model for the estimation of tubular secretion and drug interaction potential of acidic drug molecules in this process in vivo.

4-Aminobenzoic Acid↗
PubMed1997

The effects of the method of calculation on the evaluation of the pharmacokinetic parameters of oxytetracycline after intravenous administration to calves.

The aim of this study was to assess the differences in the values of the pharmacokinetic parameters attributable to the use of either linear or nonlinear regression analysis and to find the effect of weighting schemes on these differences. Six calves received 20 mg/kg oxytetracycline i.v. Blood samples were drawn during 72 h. The assay of the drug was performed microbiologically. A bicompartmental pharmacokinetic model was used, kinetic analysis being carried out by linear regression (LR) and by weighted least-squares nonlinear regression (WLSNLR). Statistical analysis included a test for normality, the Kruskall-Wallis test and ANOVA with log transformation. The A0, alpha and B0 did not show any statistically significant differences attributable to the mathematical method used. On the other hand, the statistically significant differences in the beta values found using the Kruskall-Wallis test and ANOVA with log transformation could be attributed to the different methods employed. ANOVA with log transformation determined statistically significant differences between the parameters obtained by linear analysis and those obtained by WLSNLR when the weighting (w) was 1. When weights were 1/x, 1/x2 or 1/square root of x, no statistically significant differences were found. The optimal weighting scheme was w = 1/x2 because of a more homogeneous scatter and random distribution of residuals about the abcissa axis in a plot of weighted residuals in the ordinate versus time in the abcissa. It was concluded that the use of these different procedures can give major variations in the apparent value of beta, the most important pharmacokinetic parameter. The correct selection of the weighting procedure is therefore fundamental in obtaining the best estimate of this pharmacokinetic parameter in WLSNLR.

Animals↗
PubMed2002

Ascorbic acid supplement during luteal phase in IVF.

PURPOSE: To evaluate the impact of ascorbic acid of different doses as additional support during luteal phase in infertility treatment by means of a prospective, randomized, placebo-controlled, group comparative, double-blind study. METHODS: Voluntary daily oral intake of either ascorbic acid (1, 5, or 10 g/day) or Placebo for 14 days after follicle aspiration for IVF-ET procedure. Data was obtained on 620 cases of women, age <40 years, undergoing first IVF-embryo transfer cycles in two private outpatient infertility clinics. All women were stimulated by the same protocol. The mean age was 31.73 (+/- 4.4 SD) years. RESULTS: No differences in clinical pregnancy rate and implantation rate were noted in statistical logistic regression analysis between the four intake groups. CONCLUSIONS: There was no clinical evidence of any beneficial effect, as defined by main outcome measures, of ascorbic acid on IVF-ET. Our data suggest there is no obvious value of high dosed intake of vitamin C during luteal phase in infertility treatment.

Adult↗
PubMed2002

The additive nonparametric and semiparametric Aalen model as the rate function for a counting process.

We use the additive risk model of Aalen (Aalen, 1980) as a model for the rate of a counting process. Rather than specifying the intensity, that is the instantaneous probability of an event conditional on the entire history of the relevant covariates and counting processes, we present a model for the rate function, i.e., the instantaneous probability of an event conditional on only a selected set of covariates. When the rate function for the counting process is of Aalen form we show that the usual Aalen estimator can be used and gives almost unbiased estimates. The usual martingale based variance estimator is incorrect and an alternative estimator should be used. We also consider the semi-parametric version of the Aalen model as a rate model (McKeague and Sasieni, 1994) and show that the standard errors that are computed based on an assumption of intensities are incorrect and give a different estimator. Finally, we introduce and implement a test-statistic for the hypothesis of a time-constant effect in both the non-parametric and semi-parametric model. A small simulation study was performed to evaluate the performance of the new estimator of the standard error.

Data Interpretation, Statistical↗
PubMed2003

Predictors of bicycle helmet usage among seniors.

This study identified predictors of bicycle helmet usage in a sample of seniors in Mesa, Arizona. Participants reported: days/week bicycling, usual duration, where biking occurred, helmet ownership, bicycle accidents, injuries, and age and gender. Descriptive, non-parametric statistics, and regression analysis were utilized. Seventy-four females and 123 males completed the survey. The mean age was 70.7(7.2) years. Respondents biked a mean of 4.9(2.3) days per week and averaged 40.5 (32.5) minutes of riding per day. Eighty-two participants (41.6%) owned bicycle helmets and 55 (27.9%) were observed wearing helmets. Eighty-seven (44.2%) participants biked outside their retirement community and 25 (12.7%) reported an accident within the past year. Chi-square (2, N = 197) = 0.66, p = .72) indicated no differences in of male or female helmet usage. Those who rode outside the retirement communities (chi2(2, 197) = 22.6, p = .001) were more likely to wear helmets than counterparts. Logistic regression found age to be a predictor of bicycle helmet usage.

Aged↗
PubMed2003

Effects of Seocalcitol (EB1089) on nitrosomethyl urea-induced rat mammary tumors.

Although 1,25-dihydroxyvitamin D3 is a potent cell-differentiating agent, its use in cancer prevention or therapy is precluded because it induces hypercalcemia. Synthetic analogs have been developed which inhibit tumor progression in animal models of breast cancer. One analog, Seocalcitol (EB1089) has been shown to be effective in causing regression of N-methyl-nitrosourea-induced rat mammary tumors. However, at the most effective oral dose, a significant increase in serum and urinary calcium levels were observed. In order to compare the efficacy of different dosing schedules of Seocalcitol, rats were treated either 6 times weekly (1 microg/kg) or by intermittent dosing to achieve the same total weekly dose. All dosing schedules of Seocalcitol were effective in inhibiting tumor progression. Once daily dosing was significantly more effective than intermittent dosing but was associated with a greater rise in serum calcium concentration. In order to evaluate alternative treatment strategies to limit calcemic effects, we assessed the efficacy of limiting vitamin D-induced hypercalcemia using bisphosphonates. Seocalcitol (2.5 microg/kg daily p.o. for 4 weeks) alone and in combination with pamidronate (APD 0.4 mg/kg per day s.c.) or the same dose of the bisphosphonate EB 1053 caused substantial tumor regression. No statistically significant difference was seen between combination treatment and Seocalcitol treatment alone. Co-treatment with APD or EB 1053 did not limit the rise in serum calcium induced by Seocalcitol alone. Cessation of treatment or administration of a lower dose (1microg/kg twice weekly) reversed hypercalcemia, hypercalciuria and weight loss induced by high dose Seocalcitol. However, reduction in tumor volume was maintained in the majority of animals.

Alkylating Agents↗
PubMed2002

Analysis of facial growth in subjects with syndromic ectodermal dysplasia: a longitudinal analysis.

OBJECTIVE: To examine the craniofacial growth pattern of patients diagnosed with syndromic ectodermal dysplasia. DESIGN: Mixed longitudinal analysis of lateral cephalograms. SETTING: The data were analysed using a multilevel modelling technique with the MLwiN application software and the results presented numerically and graphically. SAMPLE POPULATION: All 61 subjects had severe hypodontia with the number of absent teeth (excluding third molars) ranging from 6 to 28 (mean = 15.4). At presentation the subjects had a mean age of 133 months and were followed longitudinally for between one and five subsequent occasions (mean 2.66 occasions; mean age at completion of observation 207 months). OUTCOME MEASURES: Lateral cephalograms taken at each visit. EXPERIMENTAL VARIABLES: Analysis of four angular measurements and four linear measurements, together with one calculated ratio. RESULTS: Growth curves are presented showing the trends of craniofacial growth. CONCLUSIONS: The most significant findings were for a universal tendency for the individuals to undergo a change in sagittal relationship of the jaws, becoming markedly more Class III with time. We have also demonstrated a significant difference in growth between the anterior and posterior face heights indicating that the subjects have a tendency to an anterior growth rotation.

Adolescent↗
PubMed2000

Increased risk of lymphoproliferative disorders in relatives of patients with B-cell chronic lymphocytic leukemia: relevance of the degree of familial linkage.

We assessed the familial aggregation of chronic lymphoproliferative diseases (CLD) in 3962 relatives of 169 patients with B-cell chronic lymphocytic leukemia (B-CLL). Data collection included a self-administered questionnaire. The "relative risk" considered the connection between a higher incidence of CLD and the degree of familial linkage with the probands. The model of logistic regression was statistically significant (p < 0.001), with the probability of CLD increasing in proportion to the relationship coefficient between parents, siblings and children [(relationship coefficient 0.5; probability of CLD 1.85 (C.I. 95%, range 1.1-3%)]. CLD, particularly B-CLL, were observed in first-degree relatives of the patients with B-CLL more often than in other relatives.

Adult↗
PubMed1989

Oral contraceptives and breast cancer.

A population-based case-control study of oral contraceptive use and breast cancer was carried out among young women (less than 43 years of age) at Group Health Cooperative of Puget Sound, Seattle, Washington. Use of oral contraceptives before first pregnancy did not materially differ between cases or controls. The rate ratio estimate of breast cancer incidence in women who had used oral contraceptives before first pregnancy compared to those who had not was 0.9 (95% CI = 0.4, 2.1). There were no meaningful patterns of association between breast cancer and duration of use or formulation of oral contraceptive used before first pregnancy.

Adult↗
PubMed1989

Risk factors for ovarian cancer: a case-control study.

A hospital-based case-control study of ovarian cancer was conducted in London and Oxford between October 1978 and February 1983. Menstrual characteristics, reproductive and contraceptive history and history of exposure to various environmental factors were compared between 235 women with histologically diagnosed epithelial ovarian cancer and 451 controls. High gravidity, hysterectomy, female sterilisation and oral contraceptive use were associated with a reduced risk of ovarian cancer. Infertility and late age at menopause were associated with an increase in risk. While these factors were related, they were each found to be independently associated with ovarian cancer risk after adjusting for the effect of the other factors.

Adult↗
PubMed1982

Improved toxin/antitoxin assays for studies on the Australian paralysis tick Ixodes holocyclus.

Sensitive biological assays of toxin/antitoxin potency have been developed to assist in research on characterization of salivary toxins of the Australian paralysis tick Ixodes holocyclus and on immunity to tick paralysis. The toxin assay utilizes suckling mice (4-5 g); a quantitative paralysis index is applied over a range of doses. The antitoxin assay is based on an in vitro/in vivo neutralization test which required a sensitive toxin assay and methods of standardization of toxin preparations. This assay permits the monitoring of blood antibody levels in animals during the course of development and loss of immunity and is assisting a study into the feasibility of producing an anti-paralysis vaccine. The method also allows standardization of commercial tick paralysis antiserum. The methods and applications are described and comparisons made with previous assays. Sample data are examined statistically by regression and variance analyses; parallelism of dosage-response lines is tested and relative toxicities (toxin) or potencies (antiserum) calculated.

Analysis of Variance↗