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PubMed1985

Computer-assisted measurement of sperm swimming speed in human semen: correlation of results with in vitro fertilization assays.

A semiautomatic computerized technique for the measurement of sperm swimming speed is presented. The equipment is easy to use and would be suitable for routine clinical laboratories. The value of the sperm speed measurements obtained from over 100 individuals in relation to fertility has been studied by the correlation of these results with human in vitro fertilization (IVF) data and sperm penetrating capability in the zona-free hamster egg assay. The results show that sperm speed measurements correlate very well with those of the IVF, both human and hamster, and can be used successfully, in conjunction with multivariate statistical methods, to predict the outcomes of such techniques with about 75% accuracy.

Animals↗
PubMed2004

Graphical enhancement to support PCA-based process monitoring and fault diagnosis.

Principal component analysis (PCA) for process modeling and multivariate statistical techniques for monitoring, fault detection, and diagnosis are becoming more common in published research, but are still underutilized in practice. This paper summarizes an in-depth case study on a chemical process with 20 monitored process variables, one of which reflects product quality. The analysis is performed using the PLS_Toolbox 2.01 with MATLAB, augmented with software which automates the analysis and implements a statistical enhancement that uses confidence limits on the residuals of each variable for fault detection rather than just confidence limits on an overall residual. The newly developed graphical interface identifies and displays each variable's contribution to the faulty behavior of the process; and it aids greatly in analyzing results. The case study analyzed within shows that using the statistical enhancement can reduce the fault detection time, and the automated graphical interface implements the enhancement easily.

Artificial Intelligence↗
PubMed2000

Ability for self-care among home dwelling elderly people in a health district in Sweden.

The aim of this study was to describe the ability for self-care among home dwelling elderly in the community in a health district in western Sweden. Two self-report instruments plus a number of self-care related questions were distributed by mail to an age stratified random sample and finally completed by a total of 125 subjects. Bivariate and multivariate statistical methods were used in the analyses. The results showed that self-care ability and self-care agency decreased for respondents 75+ years of age. Self-care ability was predicted by three productive means for self-care and four risk factors.

Activities of Daily Living↗
PubMed1997

Feeding difficulty in elderly patients with dementia: confirmatory factor analysis.

The latent structure of feeding difficulty in elderly patients with dementia was investigated using multivariate statistical techniques including exploratory and confirmatory factor analysis. A survey design of 345 elderly patients with the diagnosis of dementia using a questionnaire completed by key workers and primary nurses, was used in local psychogeriatric and continuing care of the elderly facilities. Feeding difficulty and nursing intervention were estimated followed by fitting of latent variable models of feeding difficulty to the data using structural equation modelling. Three models of feeding difficulty in elderly patients with dementia, with 2, 3 and 4 factor structures respectively were compared. All three models showed a good fit to the data as assessed by several standard criteria. The 3 and 4 factor models, however, showed significantly better fit than the 2 factor model. The 4 factor model introduced a latent variable of "oral difficulty" with feeding which merits further investigation. This study demonstrates the possibility of developing reliable and validated scales for the assessment of feeding difficulty in elderly patients with dementia.

Aged↗
PubMed2000

Studies on codon usage in Entamoeba histolytica.

Codon usage bias of Entamoeba histolytica, a protozoan parasite, was investigated using the available DNA sequence data. Entamoeba histolytica having AT rich genome, is expected to have A and/or T at the third position of codons. Overall codon usage data analysis indicates that A and/or T ending codons are strongly biased in the coding region of this organism. However, multivariate statistical analysis suggests that there is a single major trend in codon usage variation among the genes. The genes which are supposed to be highly expressed are clustered at one end, while the majority of the putatively lowly expressed genes are clustered at the other end. The codon usage pattern is distinctly different in these two sets of genes. C ending codons are significantly higher in the putatively highly expressed genes suggesting that C ending codons are translationally optimal in this organism. In the putatively lowly expressed genes A and/or T ending codons are predominant, which suggests that compositional constraints are playing the major role in shaping codon usage variation among the lowly expressed genes. These results suggest that both mutational bias and translational selection are operational in the codon usage variation in this organism.

Animals↗
PubMed1997

Differentiation of Spanish strains of Echinococcus granulosus using larval rostellar hook morphometry.

Two multivariate statistical procedures (Principal Component Analysis and Discriminant Function Analysis) were used to analyse morphometric data from larval hooks of Spanish samples of Echinococcus granulosus previously characterized in physiological, biochemical and genetic studies. The 5 physical variables considered could be reduced to 2 functional variables ("length of hooks" and "number of hooks"). The number of hooks was found not to be a reliable character to differentiate between strains of this parasite. Three Spanish strains (sheep-cattle, pig, and horse strains) were identified; these results are compatible with those obtained using other techniques. We consider larval hook morphology as a valid criterion for identifying E. granulosus strains in Spain, with potential use for epidemiological studies.

Animals↗
PubMed1998

Quantitative analysis of cholesterol and cholesteryl esters in human atherosclerotic plaques using near-infrared Raman spectroscopy.

Raman spectroscopy is a non-destructive analytical technique and previous results have shown that qualitative analysis of the lipid component of human atheromatous arteries is feasible. In this paper, we describe a quantitative analytical method for cholesterol and cholesteryl esters in human atherosclerotic plaques, combined with Raman spectroscopic results, using partial least-squares (PLS) regression, a statistical multivariate method based on factorial analysis. Twenty-nine human atherosclerotic pooled samples were studied and the results of Raman spectroscopy coupled with the PLS method were compared to biochemical results. The standard error of prediction was 16.1, 13.6, 1.9, 3.3 and 3.4 mg/g for total cholesterol, free cholesterol, palmitate cholesteryl, oleate cholesteryl and linoleate cholesteryl, respectively. The repeatability of Raman spectroscopy was found to be excellent. Our results show that Raman spectroscopy is a promising technique to obtain a consistent and non-destructive quantitative analysis of cholesterol and cholesteryl esters in human atherosclerotic lesions. In situ and in vivo analysis is a possibility in the near future.

Aged↗
PubMed1982

A classification of ventricular ectopic beats.

To develop a classification of ventricular ectopic beats based on the QRS complex, the frontal and precordial QRS vectors were examined in ECGs from 71 patients. The data were first analyzed in planar coordinates to permit comparison with some previous classifications. Next, because the QRS vector is angular data, the data were transformed to spherical coordinates. Multivariate statistical methods were used. Cluster analysis aided in the separation of groups. Although at least four groups were suggested using planar coordinates, only three groupings were identified on spherical coordinates. A classification function was developed that permits assignments of ectopies into these three groups. It correctly classified 97.2% of cases. Thus, this study provides a quantitative method that significantly defines groups of ventricular ectopic beats.

Cardiac Complexes, Premature↗
PubMed1990

Health risk behaviors and attempted suicide in adolescents who report prior maltreatment.

We hypothesized that high school students who experienced prior maltreatment would be more likely than their peers to report health risk behaviors and suicide attempts. Before the establishment of a high school-based clinic, an anonymous needs assessment survey was completed by 600 adolescents (grades 9 to 12). Sociodemographic information was obtained and questions were asked about physical and sexual abuse, health-related behaviors and habits, and suicide attempts. Thirteen percent of the adolescents had been maltreated: 5.2% reported prior physical abuse, 5.4% sexual abuse, and 2.7% both physical and sexual abuse. Multivariate statistical techniques were used to clarify how previous abuse was related to adolescent risk-taking behaviors and suicide. Students with a history of physical abuse were three times more likely than non-abused peers to drink alcohol and smoke cigarettes, almost twice as likely to use illicit drugs, six times more likely to self-induce vomiting, and five times more likely to attempt suicide. A student with a history of prior sexual abuse had a three and one-half times greater chance of being sexually active and was more than three times more likely to attempt suicide. These data on a nonclinical, nondeviant population of adolescents indicate that physical or sexual abuse in childhood may have a significant impact on adolescent health risk behaviors and suicide attempts.

Adolescent↗
PubMed1997

Opiate receptor avidity and cerebral blood flow in Alzheimer's disease.

Positron emission tomography was performed on 12 Alzheimer's patients and 12 age-matched normal controls following the administration of the opiate receptor antagonist 6-deoxy-6-beta-[18F]fluoronaltrexone (cyclofoxy, CF). Tracer kinetic analysis was used to determine the volume of distribution of CF, a measure of unoccupied mu and kappa receptor density, i.e. opiate receptor avidity in 34 brain regions. Regional cerebral blood flow rates (CBF) were determined on the same day with H2[15O]. Global gray CF avidity and global gray CBF were found to be lower in the Alzheimer's patients and correlated (r=0.73, P<0.03). Regional CBF differences were superimposed on global CBF changes in the Alzheimer's patients, with the subcortex relatively spared. Multivariate statistical analyses, however, failed to demonstrate regional specificity for the CF avidity changes. Furthermore, percent changes in regional CF avidity were not correlated with percent changes in regional CBF (r=0.12, P=NS). These findings demonstrate involvement of the opiate system in Alzheimer's disease. Although, neurodegeneration is the likely underlying process responsible for both the changes in CF avidity and CBF in Alzheimer's disease, the differences with respect to the patterns of these losses suggest that the intermediate mechanisms leading from neurodegeneration to loss are distinct.

Aged↗
PubMed1992

Ambulatory monitoring of bladder pressure in low compliance neurogenic bladder dysfunction.

Upper tract dilatation is an important complication of neurogenic bladder dysfunction. Risk factors include incomplete bladder emptying with large residual volumes of urine and high tonic increases in bladder pressures during artificial filling. However, on natural bladder filling many of these patients do not have high tonic increases in detrusor pressures. We compared conventional urodynamic studies with ambulatory monitoring during natural bladder filling in 66 patients with low compliance neurogenic bladder dysfunction. There were marked differences in the tonic increase in bladder pressure during filling and in compliance during artificial bladder filling compared with ambulatory monitoring. Faster filling rates during artificial filling resulted in greater end filling pressures and lower compliance but the lowest increases in bladder pressure were found during ambulatory monitoring with natural bladder filling. During natural bladder filling significantly more patients had phasic changes in detrusor pressure; a high intensity of phasic activity during ambulatory monitoring correlated with high end filling pressures during artificial bladder filling. Upper tract dilatation was associated with large volumes of residual urine, high resting bladder pressures and low bladder compliance on filling at 100 ml. per minute. However, upper tract dilatation was most strongly associated with high intensity phasic pressure activity during natural bladder filling in combination with high residual urine volumes and high resting bladder pressures. On multivariate statistical analysis the intensity of phasic pressure activity during ambulatory monitoring was the best discriminator between patients with dilated and normal upper tracts. Our study has highlighted important differences in the results obtained by artificial filling cystometry and ambulatory monitoring during natural bladder filling. In particular, high increases in pressure did not occur during natural bladder filling, apparently being replaced by phasic activity. Within this group of patients who had the high risk factor of low bladder compliance measured during artificial bladder filling, a combination of greater residual urine volumes, greater resting pressures and greater phasic activity during natural bladder filling was found in patients with upper tract dilatation.

Adolescent↗
PubMed1983

Prognostic factors in superficial bladder tumors. A study of the European Organization for Research on Treatment of Cancer: Genitourinary Tract Cancer Cooperative Group.

A randomized clinical trial was performed on 308 patients with stage T1 carcinoma of the bladder to compare the efficacy of transurethral resection alone or followed by bladder instillations of thiotepa or VM-26 (teniposide) for 1 year. With the recurrence rate as the primary end point of interest the data from this trial were used to assess the prognostic importance of the following factors at entry into the study: number of tumors, prior recurrence rate, tumor size, grade, age, treatment group assigned and, finally, the interval between transurethral resection at entry into the study and the start of intravesical treatment. Using multivariate statistical techniques we found that the number of tumors at presentation was the most important prognostic factor followed by, in order of importance, the recurrence rate at entry and the size of the largest tumor. Of particular note was the discovery that patients with less than 1 recurrence per year at entry had a prognosis similar to patients with primary tumors, while those with a higher recurrence rate did uniformly poorly. These results show that patients with stage T1 carcinoma of the bladder form a heterogeneous group and that more aggressive therapy should be considered for patients with a poor prognosis.

Humans↗
PubMed2002

Bioconcentration of heavy metals in aquatic environments: the importance of bioavailability.

The importance of heavy metal bioavailability on the bioconcentration in aquatic biota is examined. To this purpose, mono- and multivariate statistical techniques are applied to develop correlations between heavy metal bioconcentration factor and sediment characteristics, that are expected to affect bioavailability, using a database of heavy metal concentrations in biota and sediment along with the available physicochemical characteristics. The statistical analysis shows that satisfactory correlations are obtained only when factors that affect bioavailability, such as metal oxides concentration and organic carbon content in the sediment, are taken into account.

Animals↗
PubMed2003

The application of a Marine Biotic Index to different impact sources affecting soft-bottom benthic communities along European coasts.

Following the European Water Framework Directive (2000/60/EC), the authors proposed, in a previous contribution, a Marine Biotic Coefficient (BC) to establish the ecological quality of soft-bottom benthos within European estuarine and coastal environments. The present study examines the application of the BC to the Atlantic (North Sea; Bay of Biscay; South of Spain) and Mediterranean (Spain and Greece) European coasts. The investigation assesses also the usefulness of the BC, in relation to different impact sources (e.g. drilling cuts with ester-based mud, submarine outfalls, heavy metals, industrial and mining wastes, jetties and sewerage works). The results obtained are consistent with those obtained using several methods and parameters, such as richness, diversity, evenness, Abundance-Biomass comparison plots and univariate and multivariate statistical analyses. The BC values provide a simple and clearly defined way to establish the ecological quality of soft-bottom benthos, complementary to the above mentioned methods.

Animals↗
PubMed2003

Benthos abundance pattern and species composition in conditions of pollution in Amursky Bay (the Peter the Great Bay, the Sea of Japan).

Multivariate statistical analysis of data on environmental variables and benthic macrofauna, of 30 sites from four surveys done between 1986 and 1989 in Amursky Bay, is presented. The purpose of this study is to investigate a contamination gradient, assess effects on benthic fauna and evaluate quantitative and qualitative benthic parameters. Contamination was assessed using chemical data from PCA-ordination analysis. Clear patterns were found using three categories, moderate, severe and gross. Significant changes in the number of taxa, density and ecological indices are observed between severe and moderate levels. Changes in these parameters, excluding the number of species, were also detected between gross and moderate levels. Only biomass differs non-significantly. However results of cluster analysis and MDS ordination indicate that two benthic communities exist in Amursky Bay. The most "contaminant insensitive" species polychaetes are Tharyx pacifica, Dorvillea (Schistomeringos) japonica, Dipolydora cardalia, Capitella capitata, phoronid Phoronopsis harmeri. Contaminant sensitive species include Maldane sarsi, Lumbrineris sp. and Scoloplos armiger.

Animals↗
PubMed1994

Epidemiology of triglycerides, small dense low-density lipoprotein, and lipoprotein(a) as risk factors for coronary heart disease.

In addition to LDL cholesterol, triglyceride; small, dense LDL (LDL subclass phenotype B); and lipoprotein(a) are emerging as important risk factors for CHD. Elevated plasma levels of each of these risk factors have consistently been associated with increased risk of CHD in case-control studies of white patients. In prospective studies, however, the association between triglycerides and CHD is generally not independent of HDL cholesterol in multivariate statistical analyses. Although the data are scarce, studies in women show that triglycerides are a stronger risk factor for CHD in women than in men. Although no prospective studies of LDL subclass phenotype B have been reported, a number of potential atherogenic mechanisms may be responsible for the association with CHD seen in the case-control studies. Similarly, few prospective studies of lipoprotein(a) have been published, all in Scandinavian men. The observational studies generally show an association between elevated lipoprotein(a) and CHD in whites but not in blacks. Each of these risk factors also has a genetic component. Of the two familial forms of hypertriglyceridemia, FCH has been associated with familial CHD in two cross-sectional studies. LDL subclass phenotype B is inherited consistent with a single major gene effect, and candidate gene linkage studies are in progress to map the chromosomal location of this proposed gene. Finally, lipoprotein(a) levels are largely attributable to variation at the apo(a) locus on chromosome 6. Whether other genetic variations explain the lack of reported associations between lipoprotein(a) and CHD in black populations remains to be determined. Understanding of these "non-LDL" lipoprotein-related risk factors will provide important information for the development of new, effective intervention strategies for the prevention of CHD.

Arteriosclerosis↗
PubMed1997

Lack of value of routine postpartum hematocrit determination after vaginal delivery.

OBJECTIVE: To identify risk factors associated with low postpartum hematocrits after vaginal delivery and to define lower risk categories of patients for whom routine determination of hematocrit may not be necessary. METHODS: This case-control study was designed to identify risk factors for discharge hematocrit below 27% in nonanemic patients after a vaginal delivery using the University of California, San Francisco, Perinatal Database. Multivariate statistics were used to determine the most significant risk factors. Lower risk subpopulations were analyzed to determine their rate of low discharge hematocrits. RESULTS: Risk factors associated with odds ratios greater than 1.5 for discharge hematocrit less than 27% included estimated blood loss greater than 500 mL, placenta previa, abruption, prolonged third stage, preeclampsia, prior postpartum hemorrhage, and prior cesarean delivery. Estimated blood loss > 500 mL was the most significant risk factor for discharge hematocrit less than 27% (odds ratio 4.5, 95% confidence interval 3.8, 5.4). A population without statistically significant risk factors was identified; this group had a 1.4% risk of discharge hematocrit less than 27%. CONCLUSION: Routine postpartum hematocrits are unnecessary in clinically stable patients with an estimated blood loss of less than 500 mL.

Adolescent↗
PubMed2000

A survey of obstetrician-gynecologists on their patients' alcohol use during pregnancy.

OBJECTIVE: To examine knowledge, attitudes, current clinical practices, and educational needs of obstetrician-gynecologists regarding patients' alcohol use during pregnancy. METHODS: A 20-item, self-administered questionnaire on patients' prenatal alcohol use was sent to 1000 active ACOG fellows. Responses were analyzed using univariate and multivariate statistical techniques. RESULTS: Of the 60% of the obstetrician-gynecologists who responded to the survey, 97% reported asking their pregnant patients about alcohol use. When a patient reports alcohol use, most respondents reported that they always discuss adverse effects and always advise abstinence. One fifth of the respondents (20%) reported abstinence to be the safest way to avoid all four of the adverse pregnancy outcomes cited (ie, spontaneous abortion, central nervous system impairment, birth defects, and fetal alcohol syndrome); 13% were unsure about levels associated with all of the adverse outcomes; and 4% reported that consumption of eight or more drinks per week did not pose a risk for any of the four adverse outcomes. The two resources that respondents said they needed most to improve alcohol-use assessment were information on thresholds for adverse reproductive outcomes (83%) and referral resources for patients with alcohol problems (63%). CONCLUSION: Efforts should be made to provide practicing obstetrician-gynecologists with updates on the adverse effects of alcohol use by pregnant women and with effective methods for screening and counseling women who report alcohol use during pregnancy.

Abortion, Spontaneous↗