Biomedical subjects

P Succop

Publications and source records attributed to P Succop.

At least 19 recordsLinked to original sources

PubMed2005

Body weight alterations under early corticosteroid withdrawal and chronic corticosteroid therapy with modern immunosuppression.

UNLABELLED: Weight gain is a well-known complication of corticosteroid maintenance therapy. The purpose of our study was to compare patterns of weight gain under chronic corticosteroid therapy (CCST) to those observed under early corticosteroid withdrawal (CSWD) in renal transplant recipients. METHODS: Renal transplant recipients who underwent early CSWD in IRB-approved prospective trials were compared to a historical control group of patients receiving CCST who were matched for age, sex, and race. RESULTS: One hundred sixty-nine patients with early CSWD were compared to 132 patients who received CCST. Mean population weight gain was significantly higher in CCST patients at 12 months (5.52 kg vs 3.05 kg, P < .05) posttransplant. Caucasian CSWD patients demonstrated a greater reduction in weight gain with CSWD than African Americans (mean weight decrease 2.9 vs 1.9 kg/patient, P < .05). Patients who were overweight (body mass index [BMI] 25-30) or obese (BMI > 30) demonstrated a greater reduction in weight gain with CSWD at 1 year (mean reduction in weight gain with CSWD 5.3 kg/patient and 4.4 kg/patient) than did patients of normal weight (BMI < 25; 0.1 kg/patient, P < .01 and <.05 versus BMI < 25). CONCLUSIONS: Early CSWD patients gain significantly less weight than CCST patients following transplantation. Marked variations in the effect of early CSWD on weight gain may be observed due to race and pretransplant BMI. Caucasians and overweight patients demonstrate greater benefits from CSWD than African Americans and patients with normal BMI.

Adrenal Cortex Hormones↗

PubMed2005

Corticosteroid avoidance ameliorates lymphocele formation and wound healing complications associated with sirolimus therapy.

INTRODUCTION: Sirolimus (RAPA) and corticosteroids (CS) both inhibit wound healing. To evaluate the possibility that RAPA and CS have additive effects on wound healing, we evaluated the effects of corticosteroid avoidance (CSAV) on wound healing complications in patients treated with RAPA. METHODS: One hundred nine patients treated with a CSAV regimen (no pretransplantation or posttransplantation CS) were compared with a historical control group (n = 72) that received cyclosporine (CsA), mycophenolate mofetil (MMF), and CS. The CSAV group received low-dose CsA, MMF, RAPA, and thymoglobulin induction. Complications were classified as follows: wound healing complications (WHC) or infectious wound complications (IWC). WHC included lymphocele, hernia, dehiscence, diastasis, and skin edge separation. IWC included wound abscess and empiric antibiotic therapy for wound erythema. RESULTS: The CSAV group was largely CS-free: 11% of patients received CS for rejection, 12% of patients received CS for recurrent disease, and 85% of patients are currently off CS. The CSAV group had a significantly lower incidence of WHC (13.7% vs 28%; P = .03) and lymphoceles (5.5% vs 16%; P = .02) than the control group. There was no difference in the incidence of IWC between the 2 groups. Patients who received CSAV were 18% less likely (P = .57) to develop any type of complication, 41% less likely (P = .20) to develop a WHC, and 71% less likely (P = .018) to develop a lymphocele. CONCLUSIONS: CSAV in a RAPA-based regimen results in a marked reduction in WHC and lymphoceles. Therefore, CSAV provides a promising approach for addressing WHC associated with RAPA therapy.

Adrenal Cortex Hormones↗

PubMed2005

Outcomes of patients with rejection post-polyomavirus nephropathy.

INTRODUCTION: We sought to determine the effects of rejection in renal transplant recipients with polyomavirus nephropathy (PVN). METHODS: SCr, biopsy findings, BKV serum and urine loads (Taqman PCR), and BKV antibody titers (HA inhibition assay) were analyzed by two-sample median tests and z tests in 11 patients with median follow-up of 7.3 (2.0 to 31.5) months post-PVN. All patients underwent immunosuppression reduction (ISR) as PVN treatment. RESULTS: Post-PVN, 3 (27%) patients had five rejection episodes, with 80% being mild. Median time to rejection was 18 (2 to 60) weeks. One hundred percent of patients who experienced post-PVN rejection also experienced rejection pre-PVN. Rejection episode treatments consisted of: none in one, increased tacrolimus in two, IVIG in one, IVIG and increased tacrolimus in one. Median viral loads in patients with post-PVN rejection versus those without rejection were not different in serum (2.01 x 10(4) vs 9.00 x 10(4) BKV copies/mL; P = .22) or urine (5.37 x 10(5) vs 8.93 x 10(6) BKV copies/mL; P = .28). Median BKV antibody titers were slightly lower (16384 vs 32768 HA units; P = .02) and median SCr values were significantly higher (2.7 vs 1.9 mg/dL, P = .0003) in patients who had experienced post-PVN rejection. Graft losses occurred in one rejection-free patient (chronic allograft nephropathy) and in one patient who experienced multiple acute rejection episodes, humoral rejection, and worsening PVN. CONCLUSIONS: Patients who experience rejection prior to PVN are at high risk of developing rejection post-ISR and post-PVN; however, low graft loss rates may still be achieved.

Biopsy↗

PubMed2005

Histocompatibility testing predicts acute rejection risk in early corticosteroid withdrawal regimens.

UNLABELLED: Histocompatibility testing has been shown to predict acute rejection risk in steroid-based immunosuppression. However, little evidence exists of its ability to predict acute rejection risk in corticosteroid-free patients, with no evidence in early corticosteroid withdrawal (CSWD) under modern immunosuppression. The purpose of this study was to evaluate the ability of histocompatibility testing to identify patients at high risk for acute rejection after early CSWD. METHODS: One hundred eighty-one patients were entered into six IRB-approved early CSWD regimens. Histocompatibility testing included serologic PRA, flow cytometric PRA testing by Class I and Class II MHC beads, and B cell crossmatching with pronase treatment. All rejection episodes were biopsy proven, and grading was assigned using Banff criteria. Influence of individual tests was examined using Chi square univariate and multivariate logistic regression analysis. RESULTS: Median follow-up was 23.5 months (range 7-48 months). Of 181 patients, 16% were repeat transplant recipients, 36% received deceased donor renal transplants, 48% received living related donor renal transplants, and 16% received living unrelated transplants. Overall patient survival was 97%, and death-censored graft survival was 96.5%. Acute rejection rates in the entire follow-up period were 17.7%. 12.4% in primary transplant recipients and 37% in repeat transplant recipients. Multivariate analysis revealed that HLA AB and DR locus mismatching were associated with increased acute rejection risk. Similarly, serologic PRA analysis predicted acute rejection risk; however, flow cytometry crossmatching did not predict acute rejection risk. The greatest single influence on acute rejection risk appeared to be a flow cytometric B cell crossmatch (7.94-fold increased risk). In conclusion, histocompatibility testing can identify patients at high risk for acute rejection following early CSWD. HLA matching, serologic PRA testing, and flow cytometry-based B cell crossmatching can all be used to predict acute rejection risk.

Adrenal Cortex Hormones↗

PubMed2005

Analysis of factors that influence survival with post-transplant lymphoproliferative disorder in renal transplant recipients: the Israel Penn International Transplant Tumor Registry experience.

Significant mortality is associated with post-transplant lymphoproliferative disorder (PTLD) in kidney transplant recipients (KTX). Univariate/multivariate risk factor survival analysis of US PTLD KTX reported to Israel Penn International Transplant Tumor Registry from November 1968 to January 2000 was performed. PTLD presented 18 (median) (range 1-310) months in 402 KTX. Death rates were greater for those diagnosed within 6 months (64%) versus beyond 6 months (54%, p = 0.04). No differences in death risk for gender, race, immunosuppression, EBV, B or T cell positivity were identified. Death risk increased for multiple versus single sites (73% vs. 53%, hazards ratio (HR) 1.4). A 1-year increase in age increased HR for death by 2%. Surgery was associated with increased survival (55% vs. 0% without surgery) (p < 0.0001). Patients with allograft involvement, treated with transplant nephrectomy alone (n = 20), had 80% survival versus 53% without allograft removal (n = 15) (p < 0.001). Overall survival was 69% for allograft involvement alone versus 36% for other organ involvement plus allograft (n = 19 alive) (p < 0.0001). Death risk was greater for multiple site PTLD and increasing age, and risks were additive. Univariate analysis identified increased death risk for those not receiving surgery, particularly allograft involvement alone.

Graft Rejection↗

PubMed2003

Effect of arsenic on benzo[a]pyrene DNA adduct levels in mouse skin and lung.

Concomitant exposures to arsenic and polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene (BaP) are widespread. While BaP acts by binding to and inducing mutations in critical sites on DNA, the mechanism(s) of arsenic carcinogenesis remains unknown. Data from epidemiological studies of arsenic copper smelter workers and arsenic ingestion in drinking water suggest a positive interaction for arsenic exposure and smoking and lung cancer. A previous in vitro study showed that arsenic potentiated the formation of DNA adducts at low doses of BaP and arsenic. The present study was conducted to test the effect of arsenic on BaP-DNA adduct formation in vivo. We hypothesized that arsenic co-treatment would significantly increase BaP adduct levels in C57BL/6 mouse target organs: skin and lung. Treatment groups were: five mice, -BaP/-arsenic; five mice, -BaP/+arsenic; 15 mice, +BaP/-arsenic; 15 mice, +BaP/+arsenic. Mice in the appropriate groups were provided sodium arsenite in drinking water (2.1 mg/l), ad libitum, for 13 days (starting 9 days before BaP treatment), and 200 nmol BaP/25 ml acetone (or acetone alone) was applied topically, once per day for 4 days. DNA was extracted from skin and lung and assayed by (32)P-postlabeling. Statistical comparisons were made using independent t-tests (unequal variances assumed). BaP-DNA adduct levels in the +BaP groups were significantly higher than -BaP controls. Arsenic co-treatment increased average BaP adduct levels in both lung and skin; the increase was statistically significant in the lung (P = 0.038). BaP adduct levels in the skin of individual animals were positively related to skin arsenic concentrations. These results corroborate our in vitro findings and provide a tentative explanation for arsenic and PAH interactions in lung carcinogenesis.

Animals↗

PubMed2002

Significance of radiation exposure from work-related chest X-rays for epidemiological studies of radiation workers.

BACKGROUND: Previous epidemiologic studies of workers at nuclear weapons facilities have not included X-ray exposures as part of the occupational radiation exposure. The research objective was to determine the contribution of work-related chest X-ray (WRX) exposure relative to the cumulative occupational radiation exposure. METHODS: Cases and controls were identified from a cohort of workers whose employment began as early as 1943. Medical records for 297 subjects were used to determine the bone marrow dose from their X-ray examinations. Individual dose data, however, were only available for 45 workers. Bone marrow dose estimates were calculated by converting the entrance-skin-exposure (from X-ray procedures) and occupational exposure (from monitoring data) to dose. RESULTS: Stereoscopic photofluorography delivered a bone marrow dose nearly 100 times that delivered by today's chest X-ray technique. Photofluorography was the predominant radiation source during the 1940s and 1950s. The cumulative WRX dose was, on average, 50 times their occupational doses. No correlation between occupational and WRX dose was found, but may be due to the small study size and incomplete dose data. CONCLUSIONS: These findings illustrate the importance of including WRX doses in retrospective epidemiological studies of radiation workers, especially if photofluorographic chest X-rays were performed and occupational exposure to ionizing radiation is low.

Bone Marrow↗

PubMed2001

Evaluation of the HUD lead hazard control grant program: early overall findings.

This study evaluates the effectiveness of lead hazard control methods used in the Lead Hazard Control (LHC) grant program of U.S. Department of Housing and Urban Development. The LHC Program awards funds to local jurisdictions to address lead hazards in privately owned, low-income dwellings. Grantees in 14 cities, states, or counties collected environmental data in over 2600-treated dwellings making this the largest study of residential lead hazard control ever undertaken. Grantees employed a range of treatments, the most common being replacement of windows and repair of deteriorated lead-based paint. In this paper, dust lead loading levels and blood lead levels of children (6 months-6 years, if present) were observed at four periods of time (preintervention, immediate, and 6- and 12-months postintervention) in 1212 dwellings. Dust lead loading levels were also observed in a subset of these dwellings at 24- and 36-months postintervention. The geometric mean floor and window dust lead loadings declined at least 50 and 88% (P<0.0001), respectively, immediately postintervention. Three years later, floor dust lead loadings remained at or below the immediate postintervention levels. Window dust lead loadings had moderate increases, but remained substantially reduced from preintervention levels and below clearance standards. At 1 year after intervention, geometric mean age-adjusted blood lead levels had declined from 11.0 to 8.2 microg/dL, a 26% decline (P<0.0001). The LHC Program interventions produced blood lead declines similar to or greater than the percentage changes reported in earlier 1-year lead intervention studies.

Child↗

PubMed2000

Longitudinal risk of std acquisition in adolescent girls using a generalized estimating equations model

Background: To date, few studies have used a longitudinal approach in examining risk factors for STD acquisition in teenage girls. In the present study, we examined risk of STD acquisition in adolescent girls over a three-year period using longitudinal analyses.Methods: One hundred and seventy-four girls between the ages of 12 and 16 (mean age = 14.5) participated in a longitudinal study of adolescent romantic relationships. The racial composition of the subject pool was 80% African-American and 20% Caucasian. These girls were followed for three years at six-month intervals. By the end of the study, 127 of the girls were sexually experienced, and thus, were included in the analyses regarding risk for STDs. The risk for history of STD was evaluated using a generalized estimating equations (GEE) model, which allows for the inclusion of data from subjects with missing visits. The following independent variables were entered into the model: age, race, screening IQ score, qualitative cognitive functioning, perceptions of STD prevalence among female friends, and whether a condom was used at last intercourse. Additional independent variables included number of lifetime partners (4 or more lifetime partners, 2 to 3 lifetime partners, only one partner) and age of sexual debut (less than 14 years, 14-16 years, and 17 years and older), five factors from the Family Environment Scale, and three types of parental monitoring (direct, direct when with peers, and indirect).Results: The results of the longitudinal (GEE) model indicated that having a history of an STD was significantly related to a younger age of sexual debut (p <.01), having more partners (p <.0001), being African-American (p =. 01), and having a lower screening IQ score (p <.01).Conclusions: These results suggest that risk of STD is associated with both modifiable and non-modifiable variables. Race and intellectual functioning independently contributed to STD risk, stressing the importance of utilizing prevention programs that are culturally and developmentally specific. For example, less intelligent girls may need to have information presented in a more concrete manner, with a focus on the present rather than the future. The targets of these prevention programs should continue to emphasize delaying initiation, as well as partner selection. Finally, the fact that variables for STD acquisition in this longitudinal model are comparable to previous cross-sectional studies of STD acquisition suggests that these are potent predictors of risk.

Journal Article↗

PubMed2000

A classification system for characterization of physical and non-physical work factors.

A comprehensive evaluation of work-related performance factors is a prerequisite to developing integrated and long-term solutions to workplace performance improvement. This paper describes a work-factor classification system that categorizes the entire domain of workplace factors impacting performance. A questionnaire-based instrument was developed to implement this classification system in industry. Fifty jobs were evaluated in 4 different service and manufacturing companies using the proposed questionnaire-based instrument. The reliability coefficients obtained from the analyzed jobs were considered good (0.589 to 0.862). In general, the physical work factors resulted in higher reliability coefficients (0.847 to 0.862) than non-physical work factors (0.589 to 0.768).

Energy Metabolism↗

PubMed1999

Spontaneous micronucleus frequency and age: what are normal values?

Micronucleus frequency in epidemiological studies of human exposure has become a preferred biomarker. A generally recognized observation is that micronucleus frequency increases with age. One requirement for comparison of data, which is being generated in many countries, is some common agreement about what constitutes a typical or normal background frequency of micronuclei. This is also a requirement when examining any individual value, especially one which might be considered an outlier. A mean value for normal micronucleus frequency with age is developed via the analysis of multiple studies, all of which employed large population bases and generally were conducted with the intent of determining population values. The result is presented here, with the understanding that it may over- or under-estimate the actual values in certain populations.

Adolescent↗

PubMed1999

Use of a field portable X-Ray fluorescence analyzer to determine the concentration of lead and other metals in soil samples.

Field portable methods are often needed in risk characterization, assessment and management to rapidly determine metal concentrations in environmental samples. Examples are for determining: "hot spots" of soil contamination, whether dust wipe lead levels meet housing occupancy standards, and worker respiratory protection levels. For over 30 years portable X-Ray Fluorescence (XRF) analyzers have been available for the in situ, non-destructive, measurement of lead in paint. Recent advances made possible their use for analysis of airborne dust filter samples, soil, and dust wipes. Research at the University of Cincinnati with the NITON 700 Series XRF instrument (40 millicurie Cadmium 109 source, L X-Rays) demonstrated its proficiency on air sample filters (NIOSH Method No. 7702, "Lead by Field Portable XRF; limit of detection 6 microg per sample; working range 17-1,500 microg/m3 air). Research with lead dust wipe samples from housing has also shown promising results. This XRF instrument was used in 1997 in Poland on copper smelter area soil samples with the cooperation of the Wroclaw Medical Academy and the Foundation for the Children from the Copper Basin (Legnica). Geometric mean soil lead concentrations were 200 ppm with the portable XRF, 201 ppm with laboratory-based XRF (Kevex) and 190 ppm using atomic absorption (AA). Correlations of field portable XRF and AA results were excellent for samples sieved to less than 125 micrometers with R-squared values of 0.997, 0.957, and 0.976 for lead, copper and zinc respectively. Similarly, correlations were excellent for soil sieved to less than 250 micrometers, where R-squared values were 0. 924, 0.973, and 0.937 for lead, copper and zinc, respectively. The field portable XRF instrument appears to be useful for the determination of soil pollution by these metals in industrial regions.

Adult↗

PubMed1998

The contribution of lead-contaminated house dust and residential soil to children's blood lead levels. A pooled analysis of 12 epidemiologic studies.

In 1992, the U.S. Congress passed the Residential Lead-Based Paint Hazard Reduction Act, which requires the promulgation of health-based dust lead and soil lead standards for residential dwellings to prevent undue lead exposure in children. Unfortunately, the levels of lead in house dust and soil that are associated with elevated blood lead levels among U.S. children remain poorly defined. This pooled analysis was done to estimate the contributions of lead-contaminated house dust and soil to children's blood lead levels. The results of this pooled analysis, the most comprehensive existing epidemiologic analysis of childhood lead exposure, confirm that lead-contaminated house dust is the major source of lead exposure for children. These analyses further demonstrate that a strong relationship between interior dust lead loading and children's blood lead levels persists at dust lead levels considerably below the U.S. Department of Housing and Urban Development's current postabatement standards and the Environmental Protection Agency's guidance levels. Finally, these analyses demonstrate that a child's age, race, mouthing behaviors, and study-site specific factors influence the predicted blood lead level at a given level of exposure. These data can be used to estimate the potential health impact of alternative health-based lead standards for residential sources of lead exposure.

Child, Preschool↗

PubMed1998

Reliability of questionnaire information measuring musculoskeletal symptoms and work histories.

This study was designed to assess the test-retest reliability of a musculoskeletal symptom and work history (MSWH) questionnaire administered to 522 carpenters A 10% subgroup of carpenters completing the original interview was selected for the retest interview. The areas addressed included recall of work-related musculoskeletal symptoms, prior medical conditions, prior injuries, recall of work histories, and psychosocial items. The results show that for these sections of the MSWH questionnaire the observed agreements ranged from 75.5 to 97.0%, and the calculated kappa estimates ranged from 0.46 to 0.77. Injury to body regions, job specialty, and prior medical history had the highest kappa values of K = .70 or greater. Reliability of reporting frequency of job duties such as flooring and finishing was excellent, with kappa = 0.73 (95% confidence interval = 0.66, 0.80). Based on these results, the overall reliability of the MSWH questionnaire is very good.

Adolescent↗

PubMed1998

An empirical comparison of lead exposure pathway models.

Structural equation modeling is a statistical method for partitioning the variance in a set of interrelated multivariate outcomes into that which is due to direct, indirect, and covariate (exogenous) effects. Despite this model's flexibility to handle different experimental designs, postulation of a causal chain among the endogenous variables and the points of influence of the covariates is required. This has motivated the researchers at the University of Cincinnati Department of Environmental Health to be guided by a theoretical model for movement of lead from distal sources (exterior soil or dust and paint lead) to proximal sources (interior dust lead) and then finally to biologic outcomes (handwipe and blood lead). The question of whether a single structural equation model built from proximity arguments can be applied to diverse populations observed in different communities with varying lead amounts, sources, and bioavailabilities is addressed in this article. This reanalysis involved data from 1855 children less than 72 months of age enrolled in 11 studies performed over approximately 15 years. Data from children residing near former ore-processing sites were included in this reanalysis. A single model adequately fit the data from these 11 studies; however, the model needs to be flexible to include pathways that are not frequently observed. As expected, the more proximal sources of interior dust lead and handwipe lead were the most important predictors of blood lead; soil lead often had a number of indirect influences. A limited number of covariates were also isolated as usually affecting the endogenous lead variables. The blood lead levels surveyed at the ore-processing sites were comparable to and actually somewhat lower than those reported in the the Third National Health and Nutrition Examination Survey. Lessened bioavailability of the lead at certain of these sites is a probable reason for this finding.

Child, Preschool↗

PubMed1997

Effect of chronic low-level exposure to jet fuel on postural balance of US Air Force personnel.

This study used the postural stability technique to investigate the neurological effects of cumulative low-level exposure to raw JP-8 jet fuel vapor on aircraft maintenance personnel. All subjects performed two sets of four 30-second postural sway tests. The results of mean cumulative exposure levels (in parts per million +/- standard error of mean) were the following: naphthas, 1308 +/- 292; benzene, 21.2 +/- 5.7; toluene, 23.8 +/- 6.1; and m-,o-, p-xylene, 22.7 +/- 5.4. Covariate adjusted regression analysis of the exposed group data showed a statistically significant association (P < 0.05) between the solvents (benzene, toluene, and xylene) and increased postural sway response. For all solvent exposures, the "eyes closed, on foam" test provided the strongest association between sway length and JP-8 benzene (r2 range, 0.45 to 0.52), implying subtle influence on vestibular/proprioception functionalities.

Adult↗

PubMed1996

Postural stability assessment in sewer workers.

In this study, postural stability was measured with a microcomputer-based force platform as an indirect assessment of central nervous system effect in 28 sewer workers (age range 23.4 to 64.5 years, standard deviation of 8.7 years). All workers performed four 30-second postural sway tests. The organic-solvent exposure was measured by a photo-ionization detector. The photo-ionization detector was calibrated to measure volatile organic solvents in total benzene equivalence, and concentrations were measured in various parts of the plant. The mean exposure was .32 parts per million (ppm) benzene equivalent (range of .02 to .95 ppm, standard deviation .19 ppm). Based on a covariate adjusted linear multiple-regression model, a statistically significant (p < .05) positive correlation was demonstrated between postural sway and organic-solvent exposure. These workers also had increased postural sway compared with a nonexposed population. The statistically significant correlation between postural sway determinations and organic-solvent exposure was surprising given the very low exposures measured. It is possible that the organic-solvent exposure might not be the causative agent, but rather that the solvents themselves correlate with some other causative exposure, ie, total volatile organics as implicated in the cause of sick-building syndrome.

Adult↗

PubMed1995

Effect of different vitamin A intakes on very-low-birth-weight infants.

Formula-fed infants with birth weights < or = 1500 g (n = 61) were stratified by 250-g birth-weight ranges and randomly assigned to receive one of three preterm infant formulas (vitamin A contents of 820 IU, 1640 IU, or 2900 IU/MJ; 1 RE = 3.3 IU vitamin A activity) when subjects tolerated 0.314 MJ.kg-1.d-1. Experimental formula feedings were continued until infants weighed approximately 2 kg or until hospital discharge. Vitamin A status as indicated by serum retinol and retinol-binding protein (RBP) concentrations significantly decreased during experimental formula feeding at the lowest vitamin A intake. All subjects fed the formula providing the lowest vitamin A intake had hyporetinolemia (< 0.70 mumol/L, or < 20 micrograms/dL), which occurred less frequently (P < 0.05) with the intermediate (6 of 20) and the high (6 of 21) vitamin A intakes. Other outcome measures, including increases in weight, length, and head circumference, and ventilatory support and oxygen therapy, were not different among groups. After the end of the experimental formula-feeding period, all infants were fed standard infant formulas with a vitamin A content of 715 IU/MJ. In a subset of 19 of these infants, subsequent vitamin A status was monitored at ages 6-12 mo and was found to be comparable with that of older children and adults, regardless of the vitamin A content of the formula fed during hospitalization.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗