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PubMed1979

Longitudinal changes in blood lead level in children and their relationship to season, age, and exposure to paint or plaster.

Children screened for lead poisoning in the Brownsville district of New York City in either summer or winter were followed with blood lead tests for approximately six months to one year from screening to measure longitudinal changes in blood lead level and to identify some determinants of the changes. Only minimal evidence was found of the hypothesized summer rise in blood lead level, while the predominant trend seemed to be for blood lead levels to display statistical regression to the mean. In children found to have low to intermediate blood lead levels (less than 55 microgram/100ml) at screening, variables which were found to predict a rise in blood lead level of 10 microgram/100ml or greater from winter to summer were under age three and/or exposure to paint or plaster.

Age Factors↗
PubMed1995

Heroin use during methadone maintenance treatment: the importance of methadone dose and cocaine use.

OBJECTIVES: The purpose of this study was to examine factors associated with heroin use during methadone maintenance treatment. METHODS: Logistic regression statistical models were used to examine data obtained in a cross-sectional sample of 652 methadone patients. RESULTS: Heroin use during the 3 months prior to interview was shown to be greatest among (1) patients maintained on methadone dosages of less than 70 mg/day (adjusted odds ratio [OR] = 2.1, 95% confidence interval [CI] = 1.3, 3.4) and (2) patients who used cocaine during treatment (adjusted OR = 5.9, 95% CI = 3.8, 9.1). These results were independent of treatment duration, treatment compliance, alcohol use, and socioeconomic factors. Cocaine users were more likely than nonusers of cocaine to use heroin at all methadone dosage levels. CONCLUSIONS: This study confirms and extends past research showing high-dose methadone maintenance to be important to heroin abstinence. Further investigation of the independent association between heroin use and cocaine use is needed.

Adult↗
PubMed1996

The clinical practice improvement (CPI) model and how it is used to examine the availability of pharmaceuticals and the utilisation of ambulatory healthcare services in HMOs. Results from the Managed Care Outcomes Project (MCOP).

Many American healthcare facilities have come to understand that quality controls cost. Clinical practice improvement (CPI) is a methodology that creates a clinical laboratory, built into the everyday practice setting, to find and test best practices. A CPI study is an analysis of the content and timing of individual steps in a medical care process aimed at producing better clinical outcomes for the least necessary cost over the continuum of a patient's care. Statistical regression analyses are used to determine whether and how much a particular step actually improves medical outcomes. Systematic determination of individual process steps that improve medical outcomes is the best way to develop demonstrably better care and practice. Combining CPI methodology and a data monitor creates a dynamic environment in which all patient encounters potentially contribute to improving the process of care. We describe a recent multisite study: the Managed Care Outcomes Project (MCOP). The MCOP study design permits us to compare the effects of various pharmaceutical treatments on resource utilisation in actual practice in managed-care organisations. The MCOP database is an important resource for developing information required to design systems-based disease management programmes.

Ambulatory Care↗
PubMed2006

Development of quantitative structure-activity relationships and its application in rational drug design.

Over forty years have elapsed since Hansch and Fujita published their pioneering work of quantitative structure-activity relationships (QSAR). Following the introduction of Comparative Molecular Field Analysis (CoMFA) by Cramer in 1998, other three-dimensional QSAR methods have been developed. Currently, combination of classical QSAR and other computational techniques at three-dimensional level is of greatest interest and generally used in the process of modern drug discovery and design. During the last several decades, a number of different mythologies incorporating a range of molecular descriptors and different statistical regression ways have been proposed and successfully applied in developing of new drugs, thus QSAR method has been proven to be indispensable in not only the reliable prediction of specific properties of new compounds, but also the help to elucidate the possible molecular mechanism of the receptor-ligand interactions. Here, we review the recent developments in QSAR and their applications in rational drug design, focusing on the reasonable selection of novel molecular descriptors and the construction of predictive QSAR models by the help of advanced computational techniques.

Acetolactate Synthase↗
PubMed2003

Relationship between social demographic factors and survival within one year of hospital discharge in a cohort of elderly male patients.

BACKGROUND: Little is known about the impact of social demographic factors on post-discharge mortality among the hospitalized elderly. METHODS: A one-year prospective study was conducted in a random sample of 646 male patients aged 65 or older who were discharged from a university affiliated Veterans Administration Hospital at Little Rock, AR, USA. Within 48 hours of admission, each subject completed a standardized diagnostic evaluation. Mortality was recorded for all causes. Associations between patient characteristics at hospital discharge and mortality were identified utilizing univariable and multivariable (Cox proportional hazard regression) statistical techniques. RESULTS: The mean (SD) age was 73(+/- 6) years. Within one year of hospital discharge, 83 patients (13%) died. Multiple social demographic factors were significantly associated with mortality in univariable analysis. After controlling for age, Katz index of ADL score, Charlson co-morbidity index and length of hospitalization, risk of one-year post-discharge mortality remained significantly associated with marital status, race, education, and occupational class. When all of the social demographic factors were included in a stepwise procedure, marital status, education and occupational class were selected as the strongest predictors of mortality. The adjusted hazard ratios (95% confidence interval) of mortality associated with non-married status, education < 6 years, and history of having a blue-collar occupation were 2.01 (1.29-3.15), 1.86 (1.05-3.32), and 2.16 (1.03-4.54) respectively. CONCLUSION: The results suggest that social demographic factors are independent determinants of mortality among elderly patients. These factors should be used as important indices in identifying patients at higher risk of death in clinical assessments and in prevention programs for elderly patients after hospital discharge.

Aged↗
PubMed2005

Early postoperative hepatic sonography as a predictor of vascular and biliary complications in adult orthotopic liver transplant patients.

OBJECTIVE: Our objective was to quantitatively assess the value of early posttransplantation hepatic artery resistive indexes in predicting vascular and nonvascular complications in adult orthotopic liver transplant (OLT) patients. MATERIALS AND METHODS: Between 1999 and 2001, 110 consecutive adults received grafts. Doppler sonographic graft evaluations measured main, right, and left resistive indexes within 24 to 48 hr after surgery (normal resistive index cutoff, 0.6). Clinical, operative, procedural, and radiologic reports were reviewed for vascular and biliary complications. Frequency, Student's t test, logistic, and regression statistical analyses were performed. RESULTS: even patients (6.4%) had vascular complications, including two (1.8%) hepatic artery and two (1.8%) hepatic vein stenoses, one (0.9%) hepatic vein thrombosis, two (1.8%) portal vein thromboses, and one (0.9%) thrombosis and two (1.8%) stenoses of the inferior vena cava (IVC). In 19 patients (17.3%), biliary complications included anastomotic strictures and leaks 1 week to 18 months after transplantation. In 11 patients (10%), sonographically large hematomas required surgical evacuation. In grafts with vascular complications or large hematomas, the mean early posttransplant main, right, and left indexes were significantly lower (< or = 0.6) than without these complications (p < 0.01). In grafts with and without biliary complications, mean early posttransplant main, right, and left indexes did not differ significantly. CONCLUSION: In adult OLT patients, low early posttransplant hepatic artery resistive indexes were sensitive (100%) and specific (80%) predictors for vascular complications (e.g., hepatic artery, portal vein, hepatic vein, and IVC) but not for biliary complications. All patients with indexes less than 0.6 within 24-48 hr after surgery should be monitored closely for vascular complications.

Adolescent↗
PubMed2001

Development of a questionnaire to measure concern for dental appearance.

100 adults, selected for cosmetic dental treatment in a general dental practice, completed a 42-item questionnaire designed, on the basis of previous research and the author's clinical experience, to measure concern for dental appearance. This had high internal consistency and was reduced to a questionnaire of 23 items with internal consistency shown by a standardised Cronbach alpha of .84. An exploratory factor analysis with varimax rotation identified six factors, the main one appearing to be a measure of concern for dental appearance. The high internal consistency suggests that the total score for the revised questionnaire is a measure of a construct, concern for dental appearance. Although the simplest measure of that may be contained in the items for the first factor, a much larger sample would be necessary to confirm the complex factor structure and so the questionnaire's total score is probably the more reliable measure at present. A study is summarised showing that the total score provides a measure that, in statistical regression analysis, may predict the intentions of adults to take care of the appearance of their teeth.

Adult↗
PubMed1993

Histochemical and morphometrical ageing changes in human vocal cord muscles.

A histochemical and morphometrical study of thyroarytenoid and posterior cricoarytenoid human muscles was done in 43 human adults (38 males, 5 females) with ages ranging from 46 to 87 years. Vocal cord muscles were taken from laryngectomy specimens with carcinoma (25) and from autopsies (18), excluding those with neuromuscular diseases. In all cases the studied vocal cords were clinically and histologically normal in appearance. Only 2 patients received radiotherapy or chemotherapy. Posterior cricoarytenoid muscle was studied in 6 patients with larynx cancer. Mean diameter of thyroarytenoid muscle type I fibers (n = 128) was 38.46 microns and for type II 39.68 microns; fiber percentage values (n = 127) were 44.16% for type I and 55.84% for type II. Mean diameter (n = 6) of posterior cricoarytenoid muscle type I fibers was 42.69 microns and of type II 46.56 microns; type I fibers percentage was 66.15% and type II 33.85%. Statistical regression analysis revealed a progressive decrease in thickness of the mucosa and lamina propria in the right vocal cord along the ageing process. A low increase of endomysial tissue with a low decrease in perimysium in both vocal cords was noticed. In thyroarytenoid muscle, a low increase in type I fiber percentage and a decrease in type II fiber percentage were found. Posterior cricoarytenoid muscle showed a significant decrease in type I fiber percentage and diameter, corresponding to the same increase in variables of type II fibers.

Adenosine Triphosphatases↗
PubMed1998

A mixture experiment approach for controlling the dissolution rate of a sustained-release tablet.

Several sustained-release tablet formulations with acceptable pharmacokinetic properties were found to be unstable because of the effects of lactose. Because the pharmacokinetic properties were acceptable, an attempt was made at developing stable formulations that reproduced the in vitro drug release characteristics of the unstable formulations. Through the use of a statistically designed mixture experiment, alternative formulations were generated and tested for dissolution. The dissolution data collected in the mixture experiment were used to develop a statistical regression model for identifying formulations with dissolution rates equal to those of the unstable formulations. The form of the regression model was based on the Higuchi equation. The data analysis indicated that it is possible to generate dissolution profiles that reproduce those of the original formulations by adjusting the ratios of Methocel K4MCR Premium and Methocel K100MCR Premium and by replacing the detrimental lactose with calcium phosphate dibasic anhydrous.

Calcium Phosphates↗
PubMed1995

Hospital discharge register data in the assessment of trends in acute myocardial infarction. FINMONICA AMI Register Study Team.

We evaluated the reliability hospital discharge register data in the assessment of acute myocardial infarction trends. In the FINMONICA study areas, trends in age standarized attack rates for the years 1983-90 were calculated independently from two sources: the nationwide Finnish hospital discharge register and the FINMONICA acute myocardial infarction register. The trends were compared by a statistical regression model. The trends obtained from the hospital discharge register were very similar to the trends obtained from the FINMONICA acute myocardial infarction register. The attack rates differed significantly, however, and the change in the International Classification of Diseases version from version 8 to version 9 brought on a change in the attack rates obtained from the hospital discharge register. Thus, hospital discharge register data can be used to assess acute myocardial infarction trends in the community. However, modifications of the International Classification of Diseases codes (new versions of the classification) and changes in the clinical use of the codes for coronary heart disease can have an impact on the attack rates obtained from the hospital discharge register, and the reliability of the hospital discharge register data should be regularly assessed.

Adult↗
PubMed1994

Drinking-induced blackouts among young adults: results from a national longitudinal study.

Amnesia drinking episodes among a national probability sample of 12,686 young adults are examined at two points in their lives: when they were ages 19 to 26 in 1984 and 23 through 30 in 1988. Prospective blackout patterns of early onset, late onset, chronicity, and remission were analyzed using logistic regression statistical models. Results indicate that the relative risk of short-term memory loss while drinking is significantly associated with increased alcohol consumption, age of drinking onset, the number of alcoholic relatives, and, principally, with the individual's capacity to control drinking behavior. It is concluded that the blackout remission rate observed among a substantial proportion (68%) of young adults may not fit the progressive, irreversible model of alcoholism.

Adult↗
PubMed1991

A compartmental model to analyze ruminal digestion.

In contrast to digestion models that include a discrete lag phase, a compartmental digestion model was proposed. It assumed the existence of a lag compartment and a digestion compartment. Substrate present in the digestion compartment was subject to first-order kinetics digestion. Flow of substrate from the lag compartment to the digestion compartment was proposed to be a first-order process and likely was affected by hydration of substrate, bacterial attachment, and colonization. The proposed model was compared with models that assumed the existence of a discrete lag phase. Parameter estimates for these models were obtained either through logarithmic transformation of data or nonlinear regression. Statistically, there was no difference between the compartmental model and the nonlinear model with a discrete lag phase. Differences in parameter estimates between these two models were small. Residual mean squares were higher for the logarithmically transformed models. Differences in parameter estimates between these models and the compartmental model depended on the structure of the experimental data. In a number of cases, the nonlinear parameters of the compartmental model converged to the same value, resulting in a different interpretation of the model. Residual mean squares for predicting rate of disappearance were lowest for the compartmental model.

Animals↗
PubMed1984

Recent progress in improving data processing in filtration measurements.

Nucleopore filter membranes currently utilized to assess RBC "deformability" do not meet the strict metrological requirements of a measuring gauge. They present different kinds of inhomogeneities introducing an useless information (a background noise) into measurement results and expressed as poor reproducibility. Variance reduction can only be achieved by eliminating aberrant results from a series of parallel measurements made with different membranes. To this end a procedure is proposed to identify aberrant values by an iterative statistical regression analysis of data from filter calibration and measurements on RBC suspensions and to express results as "reduced" initial flow rates for a standard filter resistance.

Erythrocytes↗
PubMed2003

Identifying epidemiological factors affecting sea lice Lepeophtheirus salmonis abundance on Scottish salmon farms using general linear models.

The variation in Lepeophtheirus salmonis sea lice numbers across 40 Scottish salmon farm sites during 1996 to 2000 was analysed using mean mobile abundance for 3 important 6 mo periods within the production cycle. Using statistical regression techniques, over 20 management and environmental variables suspected to have an effect on controlling lice populations were investigated as potential risk factors. The findings and models developed provide a picture of mobile L. salmonis infestation patterns on Scottish farm sites collectively. The results identified level of treatment, type of treatment, cage volume, current speed, loch flushing time and sea lice levels in the preceding 6 mo period to be key explanatory factors. Factors such as stocking density, site biomass, water temperature and the presence of neighbours, previously cited to be important correlates of sea lice risk from analysis of individual sites over time, were not found to be important. Variation in mobile abundance in the first half of the second year of production could be adequately explained (adjusted R2 between 55 and 72%) by the recorded data, suggesting that there is scope for management to control L. salmonis abundance, though much of the variation remains unexplained.

Animals↗
PubMed1985

Vestibular and visual rotational stimulation as treatment for attention deficit and hyperactivity.

Previously published studies report an improvement in hyperactivity following exposure to vestibular semicircular canal stimulation under eyes-open, lights-on conditions (conditions that provide visual feedback). To separate the effectiveness of vestibular stimulation from that of visual stimulation, 30 primary school children who met the criteria for having attention deficit disorder with hyperactivity were enrolled in a split-sample Latin square crossover study. The effects of just vestibular stimulation and of just visual stimulation were compared with the effect of combined vestibular and visual stimulation. Behavior ratings showed significant improvement at the end of the last treatment and at follow-up one year later; this is not easily explained by statistical regression, history, or the placebo effect. The most improvement was with solitary vestibular stimulation, which showed large effect sizes; however, differences from the other two conditions failed to reach significance at traditional p levels.

Acoustic Stimulation↗
PubMed1999

Suicide mortality in Finland during an economic cycle, 1985-1995.

This is a study on associations between suicide mortality, unemployment, divorce rate and mean alcohol consumption during an economic cycle in Finland, from 1985 to 1995. Data on annual suicide mortality, gross domestic product, unemployment, divorce rate and mean alcohol consumption were collected from official Finnish statistics. Regression analyses using a correction for serial autocorrelation were performed. Suicide mortality in both males and females increased during an economic upswing from 1985 to 1990 and decreased during an economic recession from 1990 to 1995. Suicide mortality was not associated with unemployment or divorce rate. These results are opposed to those of many previous studies. However, a significant association was found between male suicide mortality and mean alcohol consumption, in accord with other studies. In conclusion, the results suggest diversity in associations between suicide mortality, socioeconomic factors and alcohol consumption.

Alcohol Drinking↗
PubMedDate not supplied

[Long-term dynamics and prognosis for tularemia and pseudotuberculosis morbidity in the Iaroslavl region].

The trends and main factors influencing the fluctuations of the levels of tularemia and pseudotuberculosis morbidity in the Iaroslavl region were revealed by the methods of mathematical statistics (regress analysis, time-series analysis, etc.). Tularemia morbidity was 0.467 +/- 0.216 cases (1950-1997) and pseudotuberculosis morbidity was 0.979 +/- 0.297 cases (1979-1997) per 100,000 of the population. The multiple regression equations permitting the prognostication of tularemia and pseudotuberculosis morbidity in the Iaroslvl region were derived.

Humans↗