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‣ Padrão facial na dentadura decídua: estudo epidemiológico; Facial pattern in the deciduous dentition: epidemiologic study

SILVA FILHO, Omar Gabriel da; HERKRATH, Fernando José; QUEIROZ, Ana Paula Corrêa de; AIELLO, Carlos Alberto
Fonte: Dental Press Editora Publicador: Dental Press Editora
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
27.005417%
INTRODUÇÃO: é possível definir a morfologia facial e o padrão de crescimento em idade precoce, a partir da dentadura decídua completa. OBJETIVOS: frente à escassez de trabalhos na literatura pertinente ao assunto, a presente pesquisa explora o diagnóstico epidemiológico da face no estágio de dentadura decídua. METODOLOGIA: a amostra foi composta por 2.009 crianças de etnia brasileira, de ambos os gêneros, entre 3 e 6 anos de idade, no período de dentadura decídua completa, de 20 pré-escolas do município de Bauru/SP. RESULTADOS E CONCLUSÕES: baseando-se nos resultados obtidos no levantamento epidemiológico, foi encontrado - na análise em norma lateral - predomínio de crianças Padrão I (63,22%) em relação ao Padrão II (33,10%) e Padrão III (3,68%), não havendo diferenças estatisticamente significativas quanto ao gênero. Na análise em norma frontal, houve predomínio do tipo mesofacial (64,56%) em relação ao dolicofacial (21,90%) e braquifacial (13,54%), sendo que a proporção do tipo braquifacial nas meninas foi significativamente superior em relação aos meninos. Na distribuição dos tipos faciais frontais dentro dos padrões faciais sagitais ficou evidenciada uma manifestação mais freqüente do tipo dolicofacial dentro dos Padrões II e III...

‣ Enhanced classification of Chagas serologic results and epidemiologic characteristics of seropositive donors at three large blood centers in Brazil

SABINO, Ester C.; SALLES, Nanci A.; SARR, Moussa; BARRETO, Angela M.; OIKAWA, Marcio; OLIVEIRA, Claudia D.; LEAO, Silvana C.; CARNEIRO-PROIETTI, Anna B.; CUSTER, Brian; BUSCH, Michael P.; NHLBI Retrovirus Epidemiology Dono; Int Component
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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BACKGROUND: A major problem in Chagas disease donor screening is the high frequency of samples with inconclusive results. The objective of this study was to describe patterns of serologic results among donors to the three Brazilian REDS-II blood centers and correlate with epidemiologic characteristics. STUDY DESIGN AND METHODS: The centers screened donor samples with one Trypanosoma cruzi lysate enzyme immunoassay (EIA). EIA-reactive samples were tested with a second lysate EIA, a recombinant-antigen based EIA, and an immunfluorescence assay. Based on the serologic results, samples were classified as confirmed positive (CP), probable positive (PP), possible other parasitic infection (POPI), and false positive (FP). RESULTS: In 2007 to 2008, a total of 877 of 615,433 donations were discarded due to Chagas assay reactivity. The prevalences (95% confidence intervals [CIs]) among first-time donors for CP, PP, POPI, and FP patterns were 114 (99-129), 26 (19-34), 10 (5-14), and 96 (82-110) per 100,000 donations, respectively. CP and PP had similar patterns of prevalence when analyzed by age, sex, education, and location, suggesting that PP cases represent true T. cruzi infections; in contrast the demographics of donors with POPI were distinct and likely unrelated to Chagas disease. No CP cases were detected among 218...

‣ Molecular Epidemiology of Staphylococcus epidermidis in a Neonatal Intensive Care Unit over a Three-Year Period

Villari, P.; Sarnataro, C.; Iacuzio, L.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2000 Português
Relevância na Pesquisa
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Coagulase-negative staphylococci, especially Staphylococcus epidermidis, are increasingly important nosocomial pathogens, particularly in critically ill neonates. A 3-year prospective surveillance of nosocomial infections in a neonatal intensive care unit (NICU) was performed by traditional epidemiologic methods as well as molecular typing of microorganisms. The aims of the study were (i) to quantify the impact of S. epidermidis on NICU-acquired infections, (ii) to establish if these infections are caused by endemic clones or by incidentally occurring bacterial strains of this ubiquitous species, (iii) to evaluate the use of different methods for the epidemiologic typing of the isolates, and (iv) to characterize the occurrence and the spread of staphylococci with decreased glycopeptide susceptibility. Results confirmed that S. epidermidis is one of the leading causes of NICU-acquired infections and that the reduced glycopeptide susceptibility, if investigated by appropriate detection methods such as population analysis, is more common than is currently realized. Typing of isolates, which can be performed effectively through molecular techniques such as pulsed-field gel electrophoresis but not through antibiograms, showed that many of these infections are due to clonal dissemination and...

‣ Comparison of Genomic Methods for Differentiating Strains of Enterococcus faecium: Assessment Using Clinical Epidemiologic Data

Savor, Connie; Pfaller, Michael A.; Kruszynski, Julie A.; Hollis, Richard J.; Noskin, Gary A.; Peterson, Lance R.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/1998 Português
Relevância na Pesquisa
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Genomic DNA extracted from 45 vancomycin-resistant Enterococcus faecium (VRE) isolates was cleaved with HindIII and HaeIII and subjected to agarose gel electrophoresis. The ability of this method (restriction endonuclease analysis [REA]) to distinguish strains at the subspecies level was compared with results previously determined by pulsed-field gel electrophoresis (PFGE). Chart reviews were performed to provide a clinical correlation of possible epidemiologic relatedness. A likely clinical association was found for 29 patients as part of two outbreaks. REA found 21 of 21 isolates were the same type in the first outbreak, with PFGE calling 19 strains the same type. In the second outbreak with eight patient isolates, HindIII found six were the same type and two were unique types. HaeIII found three strains were the same type, two strains were a separate type, and three more strains were unique types, while PFGE found three were the same type and five were unique types. No single “ideal” method can be used without clinical epidemiologic investigation, but any of these techniques is helpful in providing focus to infection control practitioners assessing possible outbreaks of nosocomial infection.

‣ Comparative Assessment of Genotyping Methods for Epidemiologic Study of Burkholderia cepacia Genomovar III

Coenye, Tom; Spilker, Theodore; Martin, Alissa; LiPuma, John J.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/2002 Português
Relevância na Pesquisa
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We analyzed a collection of 97 well-characterized Burkholderia cepacia genomovar III isolates to evaluate multiple genomic typing systems, including pulsed-field gel electrophoresis (PFGE), BOX-PCR fingerprinting and random amplified polymorphic DNA (RAPD) typing. The typeability, reproducibility, and discriminatory power of these techniques were evaluated, and the results were compared to each other and to data obtained in previous studies by using multilocus restriction typing (MLRT). All methods showed excellent typeability. PFGE with SpeI was more reproducible than RAPD and BOX-PCR fingerprinting. The discriminatory power of the methods was variable, with PFGE and RAPD typing having a higher index of discrimination than BOX-PCR fingerprinting. In general, the results obtained by PFGE, BOX-PCR fingerprinting, and MLRT were in good agreement. Our data indicate that different genomic-based methods can be used to type B. cepacia genomovar III isolates depending on the situation and the epidemiologic question being addressed. PFGE and RAPD fingerprinting are best suited to addressing small-scale studies (i.e., local epidemiology), whereas BOX-PCR fingerprinting is more appropriate for large-scale studies (i.e., global epidemiology). In this regard...

‣ Efficacy of microbial identification system for epidemiologic typing of coagulase-negative staphylococci.

Birnbaum, D; Herwaldt, L; Low, D E; Noble, M; Pfaller, M; Sherertz, R; Chow, A W
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1994 Português
Relevância na Pesquisa
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The lack of an adequate typing system hampers our understanding of the epidemiology of infections caused by coagulase-negative staphylococci (CoNS). CoNS have become recognized as important nosocomial pathogens and the principal cause of infections associated with invasive devices. Sensitive, specific, and convenient methods are needed to evaluate whether implementing infection control guidelines reduces the risk of nosocomial infections from CoNS and other pathogens. The Microbial Identification System (MIDI) (Microbial ID Inc., Newark, Del.), a semiautomated system for fatty acid methyl ester analysis, shows considerable promise for clinical and epidemiologic applications. Its predictive accuracy and reliability were tested by using epidemiologically related and replicated CoNS isolates as well as CoNS from epidemiologically unrelated clinical infections, which were obtained from five established hospital culture collections in diverse geographic locations. Two hundred isolates were fully characterized in 5 days by one person using MIDI, and the results were similar to those produced by more expensive and time-consuming conventional typing methods. MIDI appears to be a useful screening tool that could be used before more expensive and labor-intensive molecular methods. It offers important advantages to hospital epidemiologists and clinical microbiologists who must identify and type CoNS isolates.

‣ Epidemiologic typing of Staphylococcus aureus by DNA restriction fragment length polymorphisms of rRNA genes: elucidation of the clonal nature of a group of bacteriophage-nontypeable, ciprofloxacin-resistant, methicillin-susceptible S. aureus isolates.

Blumberg, H M; Rimland, D; Kiehlbauch, J A; Terry, P M; Wachsmuth, I K
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1992 Português
Relevância na Pesquisa
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Analysis of DNA restriction fragment length polymorphisms of rRNA genes (ribotyping) was employed to assist in the epidemiologic investigation of the emergence and spread of ciprofloxacin-resistant Staphylococcus aureus at the Atlanta VA Medical Center because many isolates of interest were nontypeable by phages and harbored few plasmids useful as strain markers. Chromosomal DNAs of selected S. aureus isolates were digested initially with 20 different restriction enzymes. EcoRI appeared to give the best discrimination of hybridization banding patterns (ribotypes) and was used with all study isolates. Overall, 15 different ribotypes were seen among the 50 S. aureus isolates studied (7 ribotypes among 13 methicillin-susceptible S. aureus [MSSA] isolates and 9 ribotypes among 37 methicillin-resistant S. aureus [MRSA] isolates). Seven of eight ciprofloxacin-resistant MSSA (CR-MSSA) patient isolates had identical antibiograms, were nontypeable by phages, and had a single 22-MDa plasmid. Six of these seven CR-MSSA isolates had an identical ribotype pattern. Ribotyping distinguished this CR-MSSA strain or clone from MRSA and other MSSA isolates, including nontypeable isolates that contained a 22-MDa plasmid. Five ciprofloxacin-susceptible MSSA isolates studied had five ribotypes; one pattern was identical to the CR-MSSA clone. Twenty-three CR-MRSA isolates recovered from the Atlanta VA Medical Center had four different ribotypes. Ribotyping proved to be a useful molecular epidemiologic tool in the study of S. aureus because it differentiated isolates which were indistinguishable by more traditional methods. In addition...

‣ Epidemiologic typing and delineation of genetic relatedness of methicillin-resistant Staphylococcus aureus by macrorestriction analysis of genomic DNA by using pulsed-field gel electrophoresis.

Struelens, M J; Deplano, A; Godard, C; Maes, N; Serruys, E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1992 Português
Relevância na Pesquisa
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To evaluate the usefulness of phenotypic and genotypic analyses for the epidemiologic typing of methicillin-resistant Staphylococcus aureus (MRSA), we characterized 64 epidemic MRSA isolates and 10 sporadic methicillin-susceptible S. aureus isolates from a university hospital and 18 MRSA isolates from hospitals in different geographical areas. Chromosomal DNA macrorestriction analysis with SstII was resolved by pulsed-field gel electrophoresis and compared with antibiotype analysis, phage type analysis, and standard genomic DNA restriction analysis with BglII. Indices of the discriminatory ability of these methods were 0.982, 0.959, 0.947, and 0.959, respectively. Macrorestriction patterns of 94% of MRSA isolates from patients, personnel, and the environment associated with a nosocomial outbreak were closely related (similarity coefficient, 85 to 100%). In contrast, methicillin-susceptible S. aureus isolates showed a marked diversity of macrorestriction patterns (median similarity, 41%). MRSA isolates from other geographical areas showed diverse macrorestriction patterns, with the exception of four isolates displaying identical or closely related patterns; these isolates were associated with concurrent outbreaks in four other Belgian hospitals. A concordance of genomic DNA macrorestriction typing with phenotypic methods was observed for 60 to 65% of MRSA isolates...

‣ Tobacco use among American Indians in Oklahoma: an epidemiologic view.

Eichner, June E.; Cravatt, Kymberly; Beebe, Laura A.; Blevins, Kathleen S.; Stoddart, Martha L.; Bursac, Zoran; Yeh, Fawn; Lee, Elisa T.; Moore, William E.
Fonte: Association of Schools of Public Health Publicador: Association of Schools of Public Health
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
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OBJECTIVES: With the exception of national surveys that sample the entire U.S. population, little information exists on tobacco habits among American Indians. This study is a comparison of tobacco use findings in the 1990s among American Indians in Oklahoma, a state with a large and diverse American Indian population (39 tribes). METHODS: Data on current tobacco use are presented from two statewide surveys, the Oklahoma Youth Tobacco Survey and the Native American Behavioral Risk Factor Survey, as well as two large epidemiologic studies of chronic disease among American Indians-the Cherokee Diabetes Study and the Strong Heart Study. Three of these four sources of data involve research/surveys exclusively about American Indians. RESULTS: Nontraditional use of tobacco by American Indians occurs frequently, according to each instrument. Initiation to this habit begins in middle school and increases dramatically during high school. After age 50, reporting by individuals that they currently smoke declines steadily. CONCLUSIONS: Despite sampling different individuals for the surveys and different tribes for the epidemiologic research, results were comparable in age groups that overlapped. These findings support national data indicating that American Indians have higher prevalence rates of smoking than other racial/ethnic groups. American Indians report smoking on average about a half a pack of cigarettes per day. Individuals reporting using tobacco solely for ceremonial purposes were far fewer than habitual users. Buying tobacco products in American Indian smoke shops helps tribal economies; this fact needs to be considered for prevention programs to succeed.

‣ Health effects of electric and magnetic fields: overview of research recommendations

Savitz, David A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1993 Português
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We developed a series of articles concerning epidemiologic research on potential health effects of electric and magnetic fields. Our goal was to identify methodological issues that have arisen through past studies of cancer, reproduction, and neurobehavioral outcomes in order to suggest strategies to extend knowledge. Following an overview of relevant physics and engineering principles, cancer epidemiology of electric and magnetic fields is discussed separately with a focus on epidemiologic methods and cancer biology, respectively. Reproductive health studies, many of which focus on exposure from video display terminals are then summarized, followed by an evaluation of the limited literature on neurobehavioral outcomes, including suicide and depression. Methodological issues in exposure assessment are discussed, focusing on the challenges in residential exposure assessment and interpretation of wire configuration codes. An overview offers recommendations for priorities across these topic areas, emphasizing the importance of resolving the question of wire codes and childhood cancer. Collectively, these articles provide an array of observations and suggestions regarding the epidemiologic literature, recognizing the potential benefits to science and public policy.

‣ Potential reproductive and postnatal morbidity from exposure to polychlorinated biphenyls: epidemiologic considerations.

Rogan, W J; Gladen, B C; Wilcox, A J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1985 Português
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There is both laboratory and epidemiologic evidence that PCBs are toxic to several phases of reproduction. Workplace exposure is an important but small part of the exposure to these compounds, since most of the population has detectable levels in blood or fat. Studies in the general population on PCBs and reproduction have not been done. Some studies in workers are under way, and in epidemic PCB poisonings, small babies with a distinct clinical syndrome are seen. We review some of the laboratory and epidemiologic data and the methods available for study of reproduction in humans; study of any highly exposed group should be done and studies of spontaneous abortion, birth weight and certain congenital anomalies should look for an effect of PCBs.

‣ Epidemiologic evidence for a potentiating effect of malnutrition on child mortality.

Pelletier, D L; Frongillo, E A; Habicht, J P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1993 Português
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OBJECTIVES. Despite broad agreement that severe malnutrition contributes to child mortality in developing countries and that malnutrition has a physiologically synergistic relationship with morbidity, evidence of an epidemiologic synergism has been lacking. Also, the literature provides conflicting evidence concerning the existence of elevated mortality among children with mild to moderate malnutrition. A review of published population-based studies of anthropometry-mortality relationships was undertaken to clarify these relationships. METHODS. Six studies with the relevant data were reanalyzed to test for synergism and elevated mortality in mild to moderate malnutrition. RESULTS. The results demonstrate that mortality increases exponentially with declining weight for age. This effect is consistent across studies and there is no apparent threshold effect on mortality. The primary difference across studies is in baseline levels of mortality, which determine the quantitative impact of malnutrition on mortality in a population. CONCLUSIONS. These results indicate that mild to moderate malnutrition is associated with elevated mortality and that there is an epidemiologic synergism between malnutrition and morbidity. This previously undemonstrated finding has significant implications for child survival policies and research.

‣ Comparative Risk Assessment of the Burden of Disease from Climate Change

Campbell-Lendrum, Diarmid; Woodruff, Rosalie
Fonte: National Institute of Environmental Health Sciences Publicador: National Institute of Environmental Health Sciences
Tipo: Artigo de Revista Científica
Português
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The World Health Organization has developed standardized comparative risk assessment methods for estimating aggregate disease burdens attributable to different risk factors. These have been applied to existing and new models for a range of climate-sensitive diseases in order to estimate the effect of global climate change on current disease burdens and likely proportional changes in the future. The comparative risk assessment approach has been used to assess the health consequences of climate change worldwide, to inform decisions on mitigating greenhouse gas emissions, and in a regional assessment of the Oceania region in the Pacific Ocean to provide more location-specific information relevant to local mitigation and adaptation decisions. The approach places climate change within the same criteria for epidemiologic assessment as other health risks and accounts for the size of the burden of climate-sensitive diseases rather than just proportional change, which highlights the importance of small proportional changes in diseases such as diarrhea and malnutrition that cause a large burden. These exercises help clarify important knowledge gaps such as a relatively poor understanding of the role of nonclimatic factors (socioeconomic and other) that may modify future climatic influences and a lack of empiric evidence and methods for quantifying more complex climate–health relationships...

‣ Large Epidemiologic Studies of Gout: Challenges in Diagnosis and Diagnostic Criteria

Wijnands, José M. A.; Boonen, Annelies; Arts, Ilja C. W.; Dagnelie, Pieter C.; Stehouwer, Coen D. A.; van der Linden, Sjef
Fonte: Current Science Inc. Publicador: Current Science Inc.
Tipo: Artigo de Revista Científica
Português
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Large epidemiologic studies of gout can improve insight into the etiology, pathology, impact, and management of the disease. Identification of monosodium urate monohydrate crystals is considered the gold standard for diagnosis, but its application is often not possible in large studies. Therefore, under such circumstances, several proxy approaches are used to classify patients as having gout, including ICD coding in several types of databases or questionnaires that are usually based on the existing classification criteria. However, agreement among these methods is disappointing. Moreover, studies use the terms acute, recurrent, and chronic gout in different ways and without clear definitions. Better definitions of the different manifestations and stages of gout may provide better insight into the natural course and burden of disease and can be the basis for valid approaches to correctly classifying patients within large epidemiologic studies.

‣ Invited Commentary: Circulating Inflammation Markers and Cancer Risk—Implications for Epidemiologic Studies

Chaturvedi, Anil K.; Moore, Steven C.; Hildesheim, Allan
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
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Chronic inflammation, an established risk factor for cardiovascular disease, is increasingly being recognized as an etiologic factor in several cancers. In this issue of the Journal, Touvier et al. (Am J Epidemiol. 2013;177(1):3–13) report on the association of 7 markers of inflammation, adiposity, and endothelial function with risk of overall cancer and breast and prostate cancers in a nested case-control study carried out within the SU.VI.MAX cohort (France, 1994–2007). Consistent with previous reports on this topic, Touvier et al. focused on a limited number of markers. Future studies of inflammation and cancer should be able to capitalize on emerging multiplexed methods for the simultaneous detection of larger numbers of inflammatory markers in low-volume specimens. This should allow a more comprehensive evaluation of the role of inflammation in cancer development. In this commentary, the authors review emerging methods for measurement of multiplexed inflammation markers, the design and analytic implications of the use of these methods in epidemiologic studies, and potential public health implications of such studies. Given that many large prospective cohort studies have already collected and banked serum/plasma samples, rapid gains in our understanding of chronic inflammation and its role in cancer etiology are possible.

‣ Integrating Informative Priors from Experimental Research with Bayesian Methods: An Example from Radiation Epidemiology

Hamra, Ghassan; Richardson, David; MacLehose, Richard; Wing, Steve
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/2013 Português
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Informative priors can be a useful tool for epidemiologists to handle problems of sparse data in regression modeling. It is sometimes the case that an investigator is studying a population exposed to two agents, X and Y, where Y is the agent of primary interest. Previous research may suggest that the exposures have different effects on the health outcome of interest, one being more harmful than the other. Such information may be derived from epidemiologic analyses; however, in the case where such evidence is unavailable, knowledge can be drawn from toxicologic studies or other experimental research. Unfortunately, using toxicologic findings to develop informative priors in epidemiologic analyses requires strong assumptions, with no established method for its utilization. We present a method to help bridge the gap between animal and cellular studies and epidemiologic research by specification of an order-constrained prior. We illustrate this approach using an example from radiation epidemiology.

‣ Comparing Two Epidemiologic Surveillance Methods to Assess Underestimation of Human Stampedes in India

Ngai, Ka Ming; Lee, Wing Yan; Madan, Aditi; Sanyal, Saswata; Roy, Nobhojit; Burkle, Frederick M.; Hsu, Edbert B.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 23/09/2013 Português
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Background: Two separate but complementary epidemiologic surveillance methods for human stampedes have emerged since the publication of the topic in 2009. The objective of this study is to estimate the degree of underreporting in India. Method: The Ngai Search Method was compared to the Roy Search Method for human stampede events occurring in India between 2001 and 2010. Results: A total of 40 stampedes were identified by both search methods. Using the Ngai method, 34 human stampedes were identified. Using a previously defined stampede scale: 2 events were class I, 21 events were class II, 8 events were class III, and 3 events were class IV. The median deaths were 5.5 per event and median injuries were 13.5 per event. Using the Roy method, 27 events were identified, including 9 events that were not identified by the Ngai method. After excluding events based on exclusion criteria, six additional events identified by the Roy’s method had a median of 4 deaths and 30 injuries. In multivariate analysis using the Ngai method, religious (6.52, 95%CI 1.73-24.66, p=0.006) and political (277.09, 95%CI 5.12-15,001.96, p=0.006) events had higher relative number of deaths. Conclusion: Many causes accounting for the global increase in human stampede events can only be elucidated through systematic epidemiological investigation. Focusing on a country with a high recurrence of human stampedes...

‣ Bone lead as a biological marker in epidemiologic studies of chronic toxicity: conceptual paradigms.

Hu, H; Rabinowitz, M; Smith, D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1998 Português
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The skeleton contains the majority of the body's lead burden in both children and adults. The half-life of lead in bone is in the range of years to decades, depending on bone type, metabolic state, and subject age, among other things. Measurement of skeletal lead has benefited greatly from the recent development of X-ray fluorescence (XRF) instruments that can make rapid, safe, accurate, and relatively precise measurements of lead in bone. Two types of XRF technologies exist, LXRF and KXRF; this paper focuses on KXRF, which has been the most widely validated and used. KXRF is proving to be a powerful analytical methodology for evaluating bone lead levels as a measure of time-integrated (i.e., cumulative) lead dose in epidemiologic studies of the effects of chronic lead exposure. However, insufficient attention has been given to conceptualizing the paradigms by which bone lead levels reflect lead exposure and by which the skeleton serves as an endogenous source of lead. Consideration of these paradigms, which rely on bone lead kinetics, is necessary for the proper development of a priori hypotheses involving bone lead accumulation and release, the selection of bone sites for measurement by KXRF, and the design of epidemiologic studies involving bone lead dynamics. We discuss and present supporting evidence for a conceptual model that distinguishes two major paradigms of skeletal lead...

‣ Competing Risk Regression Models for Epidemiologic Data

Lau, Bryan; Cole, Stephen R.; Gange, Stephen J.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Português
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Competing events can preclude the event of interest from occurring in epidemiologic data and can be analyzed by using extensions of survival analysis methods. In this paper, the authors outline 3 regression approaches for estimating 2 key quantities in competing risks analysis: the cause-specific relative hazard (csRH) and the subdistribution relative hazard (sdRH). They compare and contrast the structure of the risk sets and the interpretation of parameters obtained with these methods. They also demonstrate the use of these methods with data from the Women's Interagency HIV Study established in 1993, treating time to initiation of highly active antiretroviral therapy or to clinical disease progression as competing events. In our example, women with an injection drug use history were less likely than those without a history of injection drug use to initiate therapy prior to progression to acquired immunodeficiency syndrome or death by both measures of association (csRH = 0.67, 95% confidence interval: 0.57, 0.80 and sdRH = 0.60, 95% confidence interval: 0.50, 0.71). Moreover, the relative hazards for disease progression prior to treatment were elevated (csRH = 1.71, 95% confidence interval: 1.37, 2.13 and sdRH = 2.01...

‣ Estimating the burden of shigellosis in Thailand: 36-month population-based surveillance study

Chompook,Pornthip; Samosornsuk,Seksun; von Seidlein,Lorenz; Jitsanguansuk,Supot; Sirima,Nunta; Sudjai,Sanit; Mangjit,Prasitchai; Kim,Deok Ryun; Wheeler,Jeremy G.; Todd,Jim; Lee,Hyejon; Ali,Mohammad; Clemens,John; Tapchaisri,Pramuan; Chaicumpa,Wanpen
Fonte: World Health Organization Publicador: World Health Organization
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2005 Português
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OBJECTIVE: To estimate incidence of shigellosis in the Kaengkhoi district, Saraburi Province, Thailand. METHODS: Population-based surveillance of shigellosis based in treatment centres. The detected rates of treated shigellosis were corrected for the number of cases missed due to the low sensitivity of microbiological culture methods and participants' use of health-care providers not participating in the study. FINDINGS: The overall uncorrected incidence of shigellosis was 0.6/1000 population per year (95% confidence interval (CI) = 0.5-0.8). The unadjusted incidence of treated shigellosis was highest among children less than 5 years old (4/1000 children per year; 95% CI = 3-6) and significantly lower among people aged > 5 years (0.3/1000 population per year; 95% CI = 0.2-0.5; P < 0.001). Adjusting for cases likely to be missed as a result of culture and surveillance methods increased estimates approximately five times. The majority of Shigella isolates (122/146; 84%) were S. sonnei; the rest were S. flexneri. Of the 22 S. flexneri isolates, the three most frequently encountered serotypes were 2a (36%), 1b (23%) and 3b (28%). A total of 90-95% of S. sonnei and S. flexneri isolates were resistant to tetracycline and co-trimoxazole. In contrast to S. sonnei isolates...