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At least 865 records · Page 48Linked to original sources
PubMed2003

Each lumen is a potential source of central venous catheter-related bloodstream infection.

OBJECTIVE: To determine the relative rates of microbial colonization of individual lumens in triple-lumen central venous catheters (CVCs) and calculate the chance of detecting catheter-related blood stream infection (CRBSI) if only one lumen is sampled. DESIGN: Prospective evaluation of CVCs from suspected and nonsuspected CRBSI cases. SETTING: University teaching hospital. PATIENTS: Triple-lumen CVCs from 50 cases of suspected CRBSI (a raised peripheral white blood cell count, temperature >37 degrees C, and/or local signs of infection at the catheter skin entry site) were evaluated. For comparison, 50 triple-lumen CVCs routinely removed at the end of use were evaluated. MEASUREMENTS: In both groups, peripheral blood cultures were taken before CVC removal. After CVC removal, each lumen was sampled in vitro using the endoluminal brush, and the tip was then cultured using the Maki roll technique. MAIN RESULTS: CVCs causing CRBSI had significant microbial colonization in one, two, or three lumens in ten (40%), ten (40%), or five (20%) cases, respectively. Overall, random sampling of only one lumen in CVCs causing CRBSI had a 60% chance of detecting significant colonization. CONCLUSIONS: If only one CVC lumen is sampled, a negative result does not reliably rule out infection. Each lumen of multiple-lumen CVCs should be considered as a potential source of CRBSI.

Aged↗
PubMed1997

Prevalence of tuberculous infection among students in Naples.

The aim of this study was to estimate the prevalence of tuberculous (TB) infection in Naples, Italy. The target population was defined as pupils aged 6, 9 and 13 yrs, studying in state and private schools in Naples. A stratified cluster sampling design was used. The stratification criteria were: age (6, 9, 13 yrs); type of school (state or private); and district within the town. Prevalence of TB infection was assessed through a tuberculin Tyne test. Some individual risk factors of tuberculous infection were also investigated by means of a simple questionnaire given to pupils' parents. Among observers reproducibility of test reading was also evaluated. An overall prevalence of TB infection of 5.7% (95% confidence interval (95% CI) 4.6-6.8) was observed in the 1,597 sampled subjects. Skin-test positivity was highly variable with age, ranging from 2.8 (95% CI 1.0-4.6) at 6 yrs to 9.4% (95% CI 7.1-11.7) at 13 yrs. In 458 children (28.7%) response was blindly assessed by three independent observers. Reproducibility of tuberculin skin-test reading was good, with an overall kappa value of 0.718. Only parents' drug abuse was found to be significantly associated with infection. This is the first study to evaluate the prevalence of tuberculous infection in Naples.

Adolescent↗
PubMed1999

Utility of liquid-based cytology for cervical carcinoma screening: results of a population-based study conducted in a region of Costa Rica with a high incidence of cervical carcinoma.

BACKGROUND: In a study using a split-sample design, liquid-based cytology (ThinPrep Processor, Cytyc Corporation, Boxborough, MA) was compared with the conventional Papanicolaou (Pap) smear in Guanacaste, Costa Rica. The study provides the first population-based comparison of the ThinPrep screening technology and includes "gold standard" measures of diagnostic accuracy. METHODS: The population-based study was performed among over 8000 women residing in a Costa Rican province with a high incidence of cervical carcinoma. Conventional smears were prepared and diagnosed in Costa Rica, while the residual material on the sampling device was collected into a liquid preservative and shipped to the U.S., where ThinPrep cytologic slides were prepared and diagnosed. Cytologic diagnoses based on the two techniques, categorized according to the Bethesda System, were compared with a "gold standard" final case diagnosis for each patient, also based on Bethesda terminology, that reflected an integrated interpretation of all available data, including cytology, histology, and cervicography. Results were also compared with the results of HPV DNA detection (Hybrid Capture, Digene Corporation, Silver Spring, MD). RESULTS: ASCUS was the threshold for colposcopy referral. There were significantly more women referred according to this threshold with the ThinPrep slide (12.7%) than with the conventional smear (6.7%, P<0.001). Compared with the final case diagnosis, referral by ThinPrep slides detected 92.9% of cases with high grade squamous intraepithelial lesions (HSIL) and 100% of carcinoma cases. Smears detected 77.8% of HSIL and 90.9% of carcinomas. Thus, ThinPrep cytology was significantly more sensitive in the detection of HSIL and cancer (McNemar test, P<0.001). Adjudication of cases in which the ThinPrep and smear diagnoses disagreed, using the final case diagnoses and the HPV DNA test results as reference standards, suggested that the ThinPrep method was detecting additional true SIL as opposed to false-positives. CONCLUSIONS: In a population-based study of high risk women, ThinPrep cytology demonstrated significantly increased sensitivity for detecting HSIL and carcinoma, with a concurrent significant increase in colposcopy referrals.

Cervix Uteri↗
PubMed2004

Retinoid and lipid patterns in the blubber of common dolphins (Delphinus delphis): implications for monitoring vitamin A status.

We determined retinoid concentrations in various body positions of the blubber of 25 common dolphins (Delphinus delphis) to study topographical variation in concentrations. Specimens were obtained from incidental catches and were apparently healthy. We found concentrations to be high and therefore conclude that blubber represents a significant contribution to total retinoid body load. Consequently, blubber is proposed as a tissue of choice for monitoring retinoid status in this species. Anterior-ventral blubber had the highest vitamin A concentration and posterior-dorsal the lowest. Therefore, when assessing retinoid status, topographical variation should be taken into account to ensure consistent sampling. This pattern appeared to be explained by a parallel variation in lipid content. Thus, the dynamics and body distribution of retinoids appear to be basically governed by the lipophilicity of the molecules. The highest lipid richness found in the anterior-ventral region might indicate that this region is comparatively more important for insulation and lipid storage than the dorsal posterior region. Retinoid levels did not appear to vary according to sex, but they did vary with lipid content. This should be taken into account when designing sampling protocols; for monitoring purposes, biopsies from healthy, free-ranging individuals should be preferred to samples from stranded animals.

Adipose Tissue↗
PubMed2000

Illicit drug use and emergency room utilization.

OBJECTIVE: To provide an empirical examination of the effect that chronic illicit drug use has on emergency room (ER) utilization, controlling for the potential biases introduced by correlation between unobservable determinants of chronic illicit drug use and ER utilization. DATA SOURCES/STUDY SETTING: From the National Household Survey on Drug Abuse 1994 (NHSDA94). STUDY DESIGN: Chronic illicit drug use and ER utilization are analyzed for 5,384 females and 4,177 males in 1994. The study uses a two-stage estimation technique. In the first stage, sociodemographic, drug use history, and drug use risk variables are used to estimate the probability that the subject is a chronic illicit drug user (CDU). In the second stage, the first-stage estimates provide information needed to test for the possibility of bias in the estimation of ER utilization. This bias is the result of the correlation between unobservable influences on the probability that the person is a CDU and the probability that he or she uses an ER. DATA COLLECTION/EXTRACTION METHODS: The data were collected through a multistage stratified sampling design. With the use of this methodology, the resulting data set provides the most comprehensive information on household drug use. PRINCIPAL FINDINGS: Without a correction for the possibility of endogeneity bias, chronic illicit drug use is a positive (for both males and females) and a significant (for females only) determinant of the probability of using an ER for medical treatment. After a correction for endogeneity, the influence of chronic drug use remains positive and significant for females and becomes significant for males. The corresponding change in probability for females is from 6 percent to 30 percent, while for males the increase is from an insignificant 0.1 percent to a significant 36 percent change. CONCLUSIONS: We estimate that chronic drug-using females and males, after adjustments for bias, increase the probability that they use an ER by more than 30 percent compared to their casual or non-drug-using counterparts. Therefore, policymakers and health services providers may consider designing programs to bring primary care and prevention services to facilities where drug users are more likely to seek access to care, within an ER setting.

Adolescent↗
PubMed1998

Wound management products--the evidence we need and the difficulties in obtaining it.

The management of complex wounds requires the expertise and co-ordinated effort of multiple disciplines in a variety of healthcare settings. Providers of wound care will be held increasingly responsible for the impact of clinical and economic outcomes for the patient, healthcare system and, ultimately, society as a whole. Collecting and analysing outcome data and comparing it to regional and national standards, will be the method which demonstrates the quality of service provided. This paper will review the design implications for conducting comparisons of therapies used in the management of wounds. Consideration will be given to overall design, sample size calculations, clinical setting, choice of comparator and mechanisms for exploring how efficacy and cost data can be linked. Evidence obtained from several prospective randomised clinical trials will be used as examples to support the theoretical considerations.

Clinical Nursing Research↗
PubMed1998

Early Intervention Project: can its claims be substantiated and its effects replicated?

A comprehensive report to the National Institute of Health on the diagnosis, etiology, epidemiology, and treatment of autism indicated that early intervention has the potential of being an effective intervention (Bristol et al., 1996). In spite of this positive outlook, several research and methodological questions remain regarding time of treatment initiation, intensity of treatment and duration of treatment, random assignment, comparative treatment designs, and treatment integrity. Against this backdrop we consider the claims made by the Early Intervention Project (EIP; Lovaas, 1987, 1993; McEachin, Smith, & Lovaas, 1993). The EIP claims to produce recovery from autism in 47% of the cases and to greatly reduce its severity in an additional 42% of cases. This article evaluates the EIP against threats to internal and external validity and is found to suffer from a number of methodological problems. Based on rebuttals to criticisms of their program, the EIP authors seem unwilling to admit any methodological flaws in the sampling, design, and analysis of data of the EIP. It is recommended that parents and fair hearing officers adopt an attitude of healthy skepticism before proceeding to an unqualified endorsement of the EIP as a treatment for autism.

Adolescent↗
PubMed2003

Assessing psychological change in adulthood: an overview of methodological issues.

This article reviews the current status of methods available for the analysis of psychological change in adulthood and aging. Enormous progress has been made in designing statistical models that can capture key aspects of intraindividual change, as reflected in techniques such as latent growth curve models and multilevel (random-effects) models. However, the rapid evolution of statistical innovations may have obscured the critical importance of addressing rival explanations for statistical outcomes, such as cohort differences or practice effects that could influence estimates of age-related change. Choice of modeling technique and implementation of a specific modeling approach should be grounded in and reflect both the theoretical nature of the developmental phenomenon and the features of the sampling design that selected persons, variables, and contexts for empirical observation.

Adult↗
PubMed2002

Design of withdrawal-weighted SAW filters.

This paper presents a new design algorithm for a withdrawal-weighted surface acoustic wave (SAW) transversal filter. The proposed algorithm is based on the effective transmission loss theory and a delta function model of a SAW transversal filter. The design process consists of three steps, which eventually determine eight geometrical design parameters for the filter in order to satisfy given performance specifications. First, the number of fingers in the input and output interdigital transducers (IDTs), plus their geometrical sizes is determined using the insertion loss specification. Second, the number and positions of the polarity reverses in the output IDT are determined using the bandwidth and ripple specifications. Third, the number and position for withdrawing and switching specific fingers in the output IDT and attached electrode area are determined to achieve the desired sidelobe level. The efficiency of the technique is illustrated using a sample design of an IF filter consisting of a uniform input IDT and withdrawal-weighted output IDT. The proposed algorithm is distinct from conventional techniques in that it can optimize the structural geometry of a withdrawal-weighted SAW filter in a direct manner by considering all the performance specifications simultaneously.

Acoustics↗
PubMed2002

[Occurrence and characteristics of staphylococcal enterotoxin antibodies in gynecologic patients].

OBJECTIVE: To control the occurrence of the antibodies against Staphylococcal type A and type B enterotoxin in gynaecological patients and in selected patients to determine the thermodynamic parameters of antibodies against Staphylococcal enterotoxins in their blood samples. DESIGN: Retrospective clinical study. SETTING: 2nd Department of Obstetrics and Gynaecology, P. J. Safárik University Kosice, Slovak Republic; Research Institute of Veterinary Medicine, Kosice, Slovak Republic; Department of Microbiology and Immunology, University of Veterinary Medicine, Kosice, Slovak Republic; Department of Food Microbiology and Toxicology, Food Research Institute, University of Wisconsin, Madison, USA. METHODS: The occurrence of antibodies against Staphylococcal type A and type B enterotoxin was determined in 68 patients hospitalized in Department of Obstetrics and Gynecology in Kosice. RESULTS: The occurrence of antibodies against Staphylococcal enterotoxins was determined by radioimmunoassay (RIA) in blood samples of 45 (66%) patients. The antibodies against Staphylococcal type A enterotoxin were determined in 36 (53%) patients and the antibodies against Staphylococcal type B enterotoxin were determined in 9 (13%) patients. The antibodies against both type A and type B enterotoxins were determined simultaneously in blood samples of 10% of all patients. The thermodynamic parameters of the antibodies were determined in 5 patients with positive serum findings. CONCLUSION: With regard to the existence of heterogeneous clinical findings in large amount of patients with antibodies against Staphylococcal enterotoxins, the next study of Staphylococcal enterotoxins role in pathogenesis of wide spectrum of diseases is necessary.

Adult↗
PubMed1989

Trial of antihypertensive interventions and management. Design, methods, and selected baseline results.

The Trial of Antihypertensive Interventions and Management was a multicenter randomized, placebo-controlled trial designed to assess the effectiveness of various combinations of pharmacologic and dietary interventions in the treatment of mild hypertension (diastolic blood pressure 90-100 mmHg). The primary outcome was blood pressure change between baseline and 6 months. The study consisted of a 3 X 3 factorial design wherein participants were randomly allocated to nine drug-diet treatment groups. Drugs included placebo, diuretic, and beta-blocker. Diets were usual, weight loss, and low sodium/high potassium. The basic strategy was to address clinical questions of interest by comparing mean blood pressure changes of selected drug-diet combinations. This paper describes the study including experimental design, sample size considerations, statistical analysis, organizational structure, and baseline findings.

Adult↗
PubMed1998

Obesity related phenotypes in families selected for extreme obesity and leanness.

BACKGROUND: Obesity is a multigenic trait, and special methods and sampling designs are needed for gene identification. OBJECTIVE: To describe characteristics of families selected to increase information for genetic linkage studies of obesity. DESIGN: Families having extremely obese siblings with a lean parent and sibling. SUBJECTS: 594 members of 94 Caucasian families. MEASUREMENTS: Measured height and weight, bioelectric impedance, skinfolds, circumferences and questionnaires. RESULTS: Families have an extreme range of obesity phenotypes, which are bimodally distributed. The obese individuals are predominantly women with an onset of obesity early in life. Obesity onset age was negatively correlated with level of obesity, and onset ages were correlated among family members. Individual obesity measures were highly correlated. The extreme range of phenotypes within families increases family variability and presumably gene segregation. CONCLUSION: Sampling families through extremely obese sibling pairs with a lean parent and sibling results in families with an extreme range of obesity and leanness. The large within-family variance and early age of onset should make these families highly informative for gene mapping and gene identification studies.

Adolescent↗
PubMed2002

Canadian community health survey--methodological overview.

OBJECTIVES: This article describes the design, sampling strategy, interviewing procedures, data collection and processing of the Canadian Community Health Survey (CCHS). SUMMARY: Data collection for cycle 1.1 of the CCHS began in September 2000. This first cycle provides cross-sectional data at the regional level for 136 health regions; the first half of data collected for cycle 1.1 provides data for 133 health regions. In addition to the survey methods, this article reports the sample size and rates of proxy response and non-response for each province, for the first six months of cycle 1.1. A summary of methods used to impute values that were not provided by proxy respondents is provided. A discussion of survey errors and their sources follows.

Canada↗
PubMed2003

Antidiabetic drug therapy of African-American and white community-dwelling elderly over a 10-year period.

OBJECTIVES: To determine the prevalence and predictors of antidiabetic medication use over a 10-year period in a general population of African-American and white community-dwelling elderly. DESIGN: Survey. SETTING: Five adjacent counties (one urban and four rural) in the Piedmont area of North Carolina. PARTICIPANTS: Those aged 65 and older present at the baseline (n=4,136), second (n=3,234), third (n=2,508), and fourth (n=1,633) in-person waves of the Duke Established Populations for Epidemiologic Studies of the Elderly. MEASUREMENTS: The use of six discrete categories of antidiabetic medications (insulin, first-generation oral sulfonylureas, second-generation oral sulfonylureas, metformin, oral combination therapy, and insulin combination therapy) was determined. Multivariate analyses, using weighted data adjusted for sampling design, were conducted to assess the association between antidiabetic medication use and race and other sociodemographic, health-status, and access-to-healthcare factors at baseline and 10 years later. RESULTS: Antidiabetic medications were taken by 21.4% of the population at baseline; this increased to 28.1% at the 10-year follow-up (P<.001). Insulin was the most commonly used drug at baseline (7.9%). The use of second-generation sulfonylureas increased, and use of first-generation sulfonylureas decreased over the 10-year time period. Combination antidiabetic therapy and metformin use was infrequent throughout the study. Multivariate analyses revealed that, at baseline, African Americans were nearly twice as likely (adjusted odds ratio (AOR)=1.93, 95% confidence interval (CI)=1.46-2.54) to receive any antidiabetic medication as their white counterparts. Other significant (P<.05) factors were hypertension (AOR=1.38, 95% CI=1.03-1.84), stroke (AOR=1.98, 95% CI=1.43-2.73), one or more mobility difficulties (AOR=1.29, 95% CI=1.01-1.66), continuity of care (AOR=1.74, 95% CI=1.20-2.54), and multiple doctor visits (1-4 visits, AOR=1.69, 95% CI=1.08-2.65; >/=5 visits, AOR=3.15, 95% CI=1.95-5.07). Being underweight (AOR=0.45, 95% CI=0.30-0.67) and being cognitively impaired (AOR=0.60, 95% CI=0.41-0.87) were factors significantly (P<.05) associated with a decreased risk of antidiabetic medication use. At the 10-year follow-up, similar trends were seen associating these sociodemographic, health-status, and access-to-healthcare factors with antidiabetic medication use. CONCLUSION: Antidiabetic medication use is common and increases over time for community-dwelling elderly. Race is significantly associated with antidiabetic medication use, even after controlling for other sociodemographic, health-status, and access-to-healthcare variables.

Black or African American↗
PubMedDate not supplied

Determination of alpha-amylase activity in serum and dialysate from patients using icodextrin-based peritoneal dialysis fluid.

OBJECTIVE: Low serum activity of alpha-amylase has been reported in peritoneal dialysis (PD) patients following treatment with icodextrin-based peritoneal dialysis fluid (IPDF). However, these results have been questioned because icodextrin interferes with the polysaccharide reagent included in the assay as a substrate for alpha-amylase in the sample. DESIGN: We adapted a routine method using p-nitrophenol maltoheptaoside as substrate for the analysis of total alpha-amylase in serum and dialysate from 27 patients using IPDF. Serum from 12 healthy volunteers and serum and dialysate from 19 PD patients using glucose-based peritoneal dialysis fluid (GPDF) were used as controls. For the PD patients, time on dialysis ranged from 1 to 24 months (mean 5.7 months) and time of exposure to IPDF ranged from 1 to 52 weeks. RESULTS: To test for interference and recovery, and thus to validate the alpha-amylase assay, samples were spiked with IPDF and synthetic alpha-amylase. This revealed that addition of up to 75% IPDF did not interfere with the assay. Furthermore, alpha-amylase was fully recovered when spiked in serum from patients treated with IPDF. We show that total alpha-amylase activity is considerably lower in the serum of IPDF patients (20.3 +/- 16.5 U/L, p < 0.001) than GPDF patients (85.5 +/- 51.7 U/L) and healthy persons (55.1 +/- 13.6 U/L). CONCLUSIONS: We have shown that the IL method (ILTest; Instrumentation Laboratory, Lexington, MA, USA) measures alpha-amylase activity in samples containing icodextrin metabolites. The clinical significance of reduced plasma alpha-amylase activity, as well as the relative importance of pancreatic versus salivary and tissue-bound alpha-amylase, in PD patients using IPDF is not known.

Aged↗
PubMed2002

Volume of pleural fluid required for diagnosis of pleural malignancy.

STUDY OBJECTIVES: To determine if the diagnosis of pleural malignancy is dependent on the volume of pleural fluid sampled. DESIGN AND SETTING: Single-center retrospective chart review. PATIENTS: Two hundred eighty-two patients who underwent diagnostic thoracentesis between October 1, 1998, and June 30, 1999. INTERVENTIONS: Charts were analyzed for volume of fluid, pathologic and clinical diagnoses, and demographics. Patients were classified into quartiles based on the volume of pleural fluid collected. Sensitivity and negative predictive value (NPV) were calculated for each quartile for diagnosis of pleural malignancy by cytology of pleural fluid. Further analyses were done regarding the effect of sex, race, age, smoking history, and personal history of malignancy on diagnosis. RESULTS: In total, 374 samples from 282 patients were identified (140 men and 142 women). Pleural malignancy within 6 months of initial thoracentesis was diagnosed in 99 patients (35.1%). No differences were detected for sensitivity and NPV for diagnosis of pleural malignancy between any two quartiles (p > 0.05). Samples collected from women had a higher sensitivity for predicting pleural malignancy (p = 0.0011), and those collected from nonsmokers had a slightly higher but not statistically significant sensitivity for predicting pleural malignancy (p = 0.057). Samples collected from subjects with no history of malignancy had a significantly higher NPV than samples collected from subjects with a history of malignancy (p < 0.001). After adjusting for these demographic and medical history factors, the associations of the pleural fluid volume quartiles with sensitivity and NPV did not change. CONCLUSION: The sensitivity for diagnosis of pleural malignancy is not dependent on the volume of pleural fluid extracted during thoracentesis.

Aged↗
PubMed2006

The rate of acute gastrointestinal illness in developed countries.

This paper reviews estimates of the incidence and prevalence of acute gastrointestinal illness (AGI) from 33 studies. These studies include prospective cohort studies, retrospective cross-sectional population-based surveys, and intervention trials from the United States and six other developed countries published since 1953. The incidence and prevalence estimates for AGI reported in these studies range from 0.1 to 3.5 episodes per person-year. However, comparisons of these rates are problematic owing to significant variation in study design, sampling methodology, and case definitions and should be made with caution. In the United States, the Centers for Disease Control and Prevention's (CDC) Foodborne Diseases Active Surveillance Network (FoodNet) estimates a rate of 0.65 episodes of AGI per person-year. This estimate includes diarrhea and/or vomiting of infectious or non-infectious origin, with a measure of severity (impairment of daily activities or diarrhea duration greater than 1 day), and has been adjusted for combined respiratory-gastrointestinal illnesses. However, it excludes episodes of diarrhea or vomiting due to any long-lasting or chronic illness or condition. Limitations in study design result in an unknown degree of uncertainty around this point estimate.

Acute Disease↗
PubMed1994

The importance of emotional and social isolation to loneliness among very old rural adults.

The purpose of this study was to determine the relative importance of emotional and social isolation to loneliness among very old rural adults. The sample (N = 119) was selected using a compact area cluster sampling design. Multiple regression analysis showed that emotional isolation--more specifically, the loss of spouse--accounted for more loneliness than social isolation. Hearing acuity and visits with siblings (social isolation variables) were also significant predictors of loneliness. The implications for loneliness interventions are discussed.

Aged↗