RESUMEN
Sociodemographic, living standard measure, consumption of vegetables and fruit, and dietary diversity in relation to household food security were assessed. Using a hunger score, households were categorized as food secure (n = 125) or food insecure (n = 273). Food secure respondents had a higher mean dietary diversity score (3.98; 95%CI [3.79, 4.18] versus 3.65; 95% [CI 3.53, 3.77]), were more likely to eat vitamin A-rich foods (OR 1.15; 95% CI [1.05, 1.26]), a more varied diet (DDS ≥ 4, OR 1.90; 95% CI [1.19, 3.13]), and vegetables daily (OR 3.37; 95% CI [2.00, 5.76]). Cost limited daily vegetable/fruit consumption in food insecure households. Respondents with ≥ 8 years of schooling were more likely (OR 2.07; 95% CI [1.22, 3.53]) and households receiving social grants were less likely (OR 0.37; 95% CI [0.19, 0.72]) to be food secure. Results highlight the association between dietary diversity and household food security.
Asunto(s)
Dieta Saludable , Composición Familiar , Frutas , Cooperación del Paciente , Áreas de Pobreza , Salud Suburbana , Verduras , Cuidadores/educación , Estudios Transversales , Dieta/efectos adversos , Dieta/etnología , Dieta/psicología , Dieta Saludable/economía , Dieta Saludable/etnología , Escolaridad , Composición Familiar/etnología , Abastecimiento de Alimentos/economía , Frutas/economía , Humanos , Hambre/etnología , Desnutrición/epidemiología , Desnutrición/etiología , Desnutrición/prevención & control , Encuestas Nutricionales , Cooperación del Paciente/etnología , Factores de Riesgo , Instituciones Académicas , Factores Socioeconómicos , Sudáfrica/epidemiología , Salud Suburbana/economía , Salud Suburbana/etnología , Verduras/economíaRESUMEN
Non-uniform, unclear, or incomplete presentation of food intake data limits interpretation, usefulness, and comparisons across studies. In this contribution, we discuss factors affecting uniform reporting of food intake across studies. The amount of food eaten can be reported as mean portion size, number of servings or total amount of food consumed per day; the absolute intake value for the specific study depends on the denominator used because food intake data can be presented as per capita intake or for consumers only. To identify the foods mostly consumed, foods are reported and ranked according to total number of times consumed, number of consumers, total intake, or nutrient contribution by individual foods or food groups. Presentation of food intake data primarily depends on a study's aim; reported data thus often are not comparable across studies. Food intake data further depend on the dietary assessment methodology used and foods in the database consulted; and are influenced by the inherent limitations of all dietary assessments. Intake data can be presented as either single foods or as clearly defined food groups. Mixed dishes, reported as such or in terms of ingredients and items added during food preparation remain challenging. Comparable presentation of food consumption data is not always possible; presenting sufficient information will assist valid interpretation and optimal use of the presented data. A checklist was developed to strengthen the reporting of food intake data in science communication.
Asunto(s)
Encuestas sobre Dietas , Ingestión de Alimentos , Conducta Alimentaria , Registros de Dieta , Preferencias Alimentarias , Humanos , Evaluación Nutricional , Proyectos de Investigación/normasRESUMEN
UNLABELLED: Summary. BACKGROUND: Vinculin links integrins to the cell cytoskeleton by virtue of its binding to proteins such as talin and F-actin. It has been implicated in the transmission of mechanical forces from the extracellular matrix to the cytoskeleton of migrating cells. Vinculin's function in platelets is unknown. OBJECTIVE: To determine whether vinculin is required for the functions of platelets and their major integrin, α(IIb) ß(3) . METHODS: The murine vinculin gene (Vcl) was deleted in the megakaryocyte/platelet lineage by breeding Vcl fl/fl mice with Pf4-Cre mice. Platelet and integrin functions were studied in vivo and ex vivo. RESULTS: Vinculin was undetectable in platelets from Vcl fl/fl Cre(+) mice, as determined by immunoblotting and fluorescence microscopy. Vinculin-deficient megakaryocytes exhibited increased membrane tethers in response to mechanical pulling on α(IIb) ß(3) with laser tweezers, suggesting that vinculin helps to maintain membrane cytoskeleton integrity. Surprisingly, vinculin-deficient platelets displayed normal agonist-induced fibrinogen binding to α(IIb) ß(3) , aggregation, spreading, actin polymerization/organization, clot retraction and the ability to form a procoagulant surface. Furthermore, vinculin-deficient platelets adhered to immobilized fibrinogen or collagen normally, under both static and flow conditions. Tail bleeding times were prolonged in 59% of vinculin-deficient mice. However, these mice exhibited no spontaneous bleeding and they formed occlusive platelet thrombi comparable to those in wild-type littermates in response to carotid artery injury with FeCl(3) . CONCLUSION: Despite promoting membrane cytoskeleton integrity when mechanical force is applied to α(IIb) ß(3) , vinculin is not required for the traditional functions of α(IIb) ß(3) or the platelet actin cytoskeleton.
Asunto(s)
Actinas/química , Plaquetas/metabolismo , Citoesqueleto/metabolismo , Vinculina/fisiología , Animales , Linaje de la Célula , Colágeno/química , Fibrinógeno/química , Eliminación de Gen , Megacariocitos/citología , Ratones , Ratones Endogámicos C57BL , Microscopía Fluorescente/métodos , Agregación Plaquetaria , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Vinculina/metabolismoRESUMEN
The interaction between the platelet glycoprotein (GP) Ib-IX complex and von Willebrand factor (VWF) initiates both hemostasis and pathological thrombosis. This interaction is not only the first adhesive event of platelets at sites of vessel injury, but also facilitates fibrinogen binding to alpha(IIb)beta(3), which subsequently results in platelet aggregation. Since it has been suggested that GP Ib-IX clustering may promote platelet activation, we investigated the effect of such clustering on both VWF-GP Ib-IX and fibrinogen-alpha(IIb)beta(3) bonds using optical tweezers. In our system, fusion of tandem repeats of FK506-binding protein (FKBP) to the cytoplasmic tail of the GP IX subunit of the GP Ib-IX complex allowed subsequent receptor clustering within the plasma membrane by the bivalent, cell-permeant small molecule ligand AP20187. We measured binding forces between polystyrene beads coated with either plasma-derived VWF or the VWF A1 domain and GP Ib-IX(FKBP)2, and those between fibrinogen-coated beads and alpha(IIb)beta(3) expressed on Chinese hamster ovary cells. The minimal detachment force between GP Ib-IX(FKBP)(2) and A1 or plasma-derived VWF doubled after AP20187 was added. The binding force between immobilized fibrinogen and alpha(IIb)beta(3) was not changed by the clustering agent; however, the strength of single fibrinogen-alpha(IIb)beta(3) bonds increased significantly after ligation of GP Ib-IX(FKBP)(2) by A1. These results demonstrate that GP Ib-IX clustering increases the overall strength of its interaction with VWF. Furthermore, signals from GP Ib-IX can activate alpha(IIb)beta(3), thereby increasing the strength of its interaction with fibrinogen.
Asunto(s)
Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Complejo GPIb-IX de Glicoproteína Plaquetaria/fisiología , Glicoproteínas de Membrana Plaquetaria , Agregación de Receptores , Tacrolimus/análogos & derivados , Factor de von Willebrand/metabolismo , Adhesividad , Animales , Células CHO , Adhesión Celular , Cricetinae , Fibrinógeno , Humanos , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/genética , Complejo GPIb-IX de Glicoproteína Plaquetaria/genética , Complejo GPIb-IX de Glicoproteína Plaquetaria/metabolismo , Unión Proteica , Tacrolimus/farmacología , TransfecciónRESUMEN
We have evaluated the relative contribution of the adhesive ligands, von Willebrand factor (vWF), fibrinogen (Fg) and thrombospondin (TSP), all surface-expressed on washed platelets (WP) activated with a threshold thrombin concentration (approximately 0.04 U/ml), to platelet microaggregation (PA) at shear rates (G) from 300-2000 s(-1). In suspensions of thrombin-activated WP sheared immediately (tau0), all three ligands were required for optimal aggregation at all G, as shown by a 50-70% inhibition of capture efficiencies of PA (measured from initial rates of PA), by antibodies (Abs) directed against each protein. This aggregation involved both GPIb and GPIIbIIIa, as indicated by approximately 80% and 100% inhibition by Ab 6D1 and Ab 10E5, respectively. For WP preexposed to thrombin for 10 min to ensure maximal surface expression of secreted ligands and activated GPIIbIIIa (tau0), vWF was predominantly required at all G (63-75% inhibition by anti-vWF Ab), together with TSP (35-50% inhibition by anti-TSP Ab). Under these conditions, Fg was extensively converted to fibrin, so that fibrin, rather than Fg, could participate in microaggregation, with GPIb less required than GPIIbIIIa as indicated by a 30-60% inhibition by Ab 6D1 as compared to 100% inhibition by Ab 10E5. Our results show that interactions between multiple ligands and receptors favour microaggregation depending on shear and thrombin activation conditions.
Asunto(s)
Fibrinógeno/fisiología , Agregación Plaquetaria/fisiología , Trombina/farmacología , Trombospondinas/fisiología , Factor de von Willebrand/fisiología , Anticuerpos Monoclonales , Fibrina/metabolismo , Fibrinógeno/inmunología , Humanos , Activación Plaquetaria/efectos de los fármacos , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/inmunología , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/fisiología , Complejo GPIb-IX de Glicoproteína Plaquetaria/inmunología , Complejo GPIb-IX de Glicoproteína Plaquetaria/fisiología , Reología , Estrés Mecánico , Trombospondinas/inmunología , Factor de von Willebrand/inmunologíaRESUMEN
Previous studies evaluating requirements for occupancy of thrombin receptors in normal platelet secretion and aggregation, using the thrombin antagonists hirudin and PPACK (D-Phe-Pro-Arg-chloromethylketone), have suggested that at low thrombin activating concentrations (0.025-0.13 U/ml), occupancy was required only in the first 45-60 s following activation. In our study, we differentiate between thrombin receptor occupancy requirements for surface expression of secreted adhesive proteins, for activation of GPIIb-IIIa receptors, and for aggregation of washed platelets (WP) in laminar shear flow. Platelets activated with 0.05 U/ml thrombin for 10 min to allow maximal secretion (hereafter referred to as "pre-activated platelets"), then sheared, showed a 50-70% decrease in platelet counts after 60 s of shear. Treatment of pre-activated platelets with hirudin or PPACK produced a 65% reduction of capture efficiencies, alphaG (reflecting experimental/theoretical initial rates of aggregation), as well as a 30-40% decrease in the surface expression of von Willebrand factor (vWF) and thrombospondin (TSP). However, alpha-granule membrane P-selectin expression and numbers of activated GPIIb-IIIa receptors were comparable for treated and non-treated platelets. No significant difference in any of the parameters tested was observed when platelets were similarly pre-activated with 0.2 U/ml thrombin, due to treatment with thrombin antagonists. Binding of soluble FITC-vWF (GRGDSP-sensitive) to pre-activated, thrombin antagonist treated platelets, was greatly reduced (> or =80%). Soluble Fg was shown to bind to antagonist-treated pre-activated platelets, but could not significantly enhance platelet aggregation. Although occupancy of thrombin receptors by catalytically active thrombin is required transiently for secretion and activation of platelets, there is a further requirement for thrombin occupancy at low thrombin concentrations, for optimizing initial rates of platelet aggregation, surface expression of vWF and TSP, and activated GPIIb-IIIa ligand recognition.
Asunto(s)
Hemostáticos/farmacología , Agregación Plaquetaria/efectos de los fármacos , Receptores de Trombina/fisiología , Trombina/farmacología , Trombospondinas/biosíntesis , Factor de von Willebrand/biosíntesis , Plaquetas/fisiología , Hemostáticos/metabolismo , Humanos , Trombina/metabolismoRESUMEN
We recently reported that washed platelets (WP) activated with ADP and expressing surface-bound vWF aggregated in flow through small tubes or in a cylindrical couette device at physiological shear rates of G = 300 s(-1)-1000 s(-1) in the absence of exogenous ligands, with GPIb-vWF partially, and activated GPIIb-IIIa totally required for the aggregation. We have now extended these studies to aggregation of platelets "activated" with ristocetin or thrombin. Washed platelet suspensions with added soluble vWF and ristocetin (0.3-0.75 mg/ml), or activated with thrombin (0.01-0.5 U/ml) but no added ligand, were sheared in a coaxial cylinder device at uniform shear rate, G = 1000 s(-1). The collision capture efficiency (alphaG) with which small aggregates form (= experimental/calculated initial rates of aggregation) was correlated with vWF platelet binding assessed by flow cytometry. The vWF-GPIb interaction was exclusively able to support ristocetin-mediated shear aggregation of metabolically active platelets, with very few vWF monomer equivalents bound per platelet (representing < or = 10 molecules of 10 million Da) required to yield high capture efficiencies (alphaG = 0.38+/-.02; n = 11), suggesting rapid and stable bond formations between vWF and GPIb. However, platelet surface-expressed vWF, generated by addition of thrombin to washed platelets, was found to mediate platelet aggregation with alphaG = 0.08+/-.01 (n = 6), surprisingly comparable to that previously reported for WP and ADP activation. Blocking the GPIIb-Illa receptor decreased alphaG by 95+/-3% (n =3), while a monoclonal antibody to the vWF site on GPIb caused a 49+/-7% (n = 8) decrease in alphaG. The partial role for GPIb thus appears to reflect a facilitative function for increasing contact time between flowing platelets, and allowing engagement of the GPIIb-IIa receptor to yield stable attachment.
Asunto(s)
Antibacterianos/farmacología , Agregación Plaquetaria/efectos de los fármacos , Agregación Plaquetaria/fisiología , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/fisiología , Complejo GPIb-IX de Glicoproteína Plaquetaria/fisiología , Ristocetina/farmacología , Trombina/farmacología , Plaquetas/fisiología , HumanosRESUMEN
Fibrinogen (Fg) mediates platelet aggregation and adhesion to artificial surfaces. The carboxyl terminus of the gamma chain of Fg (residues AGDV at gamma408-411) is known to play an exclusive role in platelet aggregation, while there is no known role for the consensus RGD sites in the Aalpha chain. In this study, we used flow cytometry to measure the coaggregation (CA) of platelets with Fg-coated beads, and investigated which domains in surface-immobilized Fg support platelet adhesion. CA of platelets with Fg-beads was nearly abolished in the presence of 4A5, a monoclonal antibody (mAb) whose epitope includes AGDV, while Z69/8, a mAb that also binds to the gamma chain carboxyl terminus but does not cover AGDV, had little effect. When beads were coated with recombinant Fg (rFg) lacking AGDV, CA was similarly abolished. In contrast, beads coated with Fg that lacked the RGDS site, supported platelet CA as did intact Fg. These results were confirmed in experiments that measured the binding of activated soluble glycoprotein IIb and IIIa (GPIIbIIIa), the platelet membrane glycoprotein complex known to be the Fg receptor, to immobilized Fg. This binding was inhibited by mAb 4A5, but not by mAb Z69/8. Binding was totally retained when beads were coated with Fg lacking RGDS, but was completely lost when beads were coated with Fg lacking AGDV. These results demonstrated that the AGDV sequence on the carboxyl terminus of the gamma chain of Fg plays an exclusive role in platelet adhesion to surface-immobilized Fg, while the carboxyl terminus of the Aalpha chain, including a consensus RGD site, is not required.
Asunto(s)
Plaquetas/fisiología , Fibrinógeno/fisiología , Oligopéptidos/fisiología , Fragmentos de Péptidos/fisiología , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/metabolismo , Sitios de Unión de Anticuerpos , Adhesión Celular/fisiología , Fibrinógeno/genética , Fibrinógeno/inmunología , Fibrinógeno/metabolismo , Humanos , Microesferas , Mutagénesis Sitio-Dirigida , Oligopéptidos/inmunología , Fragmentos de Péptidos/inmunología , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Poliestirenos , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/metabolismoAsunto(s)
Suplementos Dietéticos , Industria Farmacéutica/legislación & jurisprudencia , Legislación de Medicamentos , Legislación Alimentaria , Utilización de Medicamentos , Drogas en Investigación , Humanos , Política Nutricional , Médicos , Etiquetado de Productos , Estados Unidos , United States Food and Drug AdministrationRESUMEN
We previously showed that ADP activation of washed human platelets in plasma-free suspensions supports aggregation at moderate shear stress (0.4-1.6 Nm-2) in Poiseuille flow. Although most activated platelets expressed maximal fibrinogen-occupied GPIIb-IIIa receptors, aggregation appeared to be independent of bound fibrinogen, but blocked by the hexapeptide GRGDSP. Here, we tested the hypothesis that von Willebrand factor (vWF) secreted and expressed on activated platelets mediates aggregation at moderate shear rates from 300 to 1000 s-1 corresponding to shear stresses from 0.3 to 1.1 Nm-2. Relatively unactivated platelets (< 15% expressing prebound fibrinogen) were prepared from acidified citrated platelet rich plasma (cPRP) by single centrifugation with 50 nM stable prostacyclin derivative ZK 36374 and resuspended in Tyrodes-albumin at 5 x 10(4) cells microliter-1. Flow cytometric measurements with monoclonal antibody (mAb) 2.2.9 reporting on surface-bound vWF, and with mAb S12 reporting on alpha-granule secreted P-selectin, showed that 65% and 80%, respectively, of all platelets were maximally activated with respect to maximal secretion and surface expression of these proteins. "Resting" washed platelets exhibited both surface-bound vWF and significant P-selectin secretion. We showed that mAbs 6D1 and NMC4, respectively blocking the adhesive domains on the GPIb receptor recognizing vWF, and on the vWF molecule recognizing the GPIb receptor, partially inhibited ADP-induced aggregation under shear in Couette flow, the degree of inhibition increasing with increasing shear stress. In contrast, mAb 10E5, blocking the vWF binding domain on GPIIb-IIIa, essentially blocked all aggregation at the shear rates tested. We conclude that vWF, expressed on ADP-activated platelets, is at least the predominant cross-bridging molecule mediating aggregation at moderate shear stress. There is an absolute requirement for free activated GPIIb-IIIa receptors, postulated to interact with platelet-secreted, surface bound vWF. The GPIb-vWF cross-bridging reaction plays a facilitative role becoming increasingly important with increasing shear stress. Since aurin tricarboxylic acid, which blocks the GPIb binding domain on vWF, was also found to completely block aggregation in Poiseuille flow, we conclude that it too affects the GPIIb-IIIa interaction.
Asunto(s)
Adenosina Difosfato/farmacología , Plaquetas/efectos de los fármacos , Agregación Plaquetaria , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/farmacología , Complejo GPIb-IX de Glicoproteína Plaquetaria/metabolismo , Factor de von Willebrand/metabolismo , Anticuerpos Monoclonales/inmunología , Fibrinógeno/análisis , Citometría de Flujo , Humanos , Activación Plaquetaria , Propiedades de SuperficieRESUMEN
This article catalogs some of the Centers for Disease Control and Prevention's (CDC) more important information resource offerings, which make public health information accessible via computer and automated telephone systems and on electronic media (diskette and CD-ROM). We review mechanisms for (1) finding and retrieving CDC reports, (2) querying CDC's numeric data files, (3) transmitting surveillance and other data files to CDC, (4) exchanging electronic mail with CDC staff, and (5) disseminating state and local public health information and data by using CDC tools. Each resource is followed with a section on how to obtain access to these resources.
Asunto(s)
Centers for Disease Control and Prevention, U.S./organización & administración , Control de Enfermedades Transmisibles , Servicios de Información , Sistema de Registros , Telecomunicaciones , Toxicología , CD-ROM , Redes de Comunicación de Computadores , Bases de Datos Factuales , Humanos , Relaciones Interprofesionales , National Institute for Occupational Safety and Health, U.S. , Administración en Salud Pública , Estados UnidosRESUMEN
Dynamic and quantitative studies of the binding of fibrinogen (Fg) to its receptor, GPIIb-IIIa, on activated platelets, leading to platelet aggregation, are best studied with fluorescently-labelled Fg by flow cytometry. Due to conflicting reports on the functionality of FITC-labelled Fg, we have developed a reproducible and 'mild' labelling of fibrinogen with FITC-celite at pH 7.4-8.5 for direct and dynamic studies of specific Fg binding to activated platelets evaluated for native platelet-rich plasma, for washed platelets, and for activated, fixed platelets. We have demonstrated the equivalence of FITC-labelled and unlabelled Fg for binding to activated GPIIb-IIIa receptors, and in the rate and extent of mediating platelet aggregation. We found that FITC-Fg labelled at pH > or = 9 had reduced to absent specific binding to activated platelets, whether using soluble FITC or FITC-celite. The FITC-labelled Fg must be diluted 3-fold with unlabelled Fg when evaluating maximal Fg binding to activated platelets in order to prevent autoquenching of the FITC-Fg which leads to underestimation of Fg levels. The dissociation constant (KD) of Fg on stable preparations of activated, fixed platelets, determined with FITC-Fg binding to platelets by flow cytometry, was in the range reported for 125I-labelled Fg, 70-255 nm with Bmax = 10000-25000 Fg per platelet (n = 20). The FITC-Fg was used to monitor Fg binding to activated platelets directly by plasma, as well as to evaluate platelet subpopulations which maximally bind Fg according to the concentration of ADP used as activator. It is expected that this 'mildly' labelled FITC-Fg will stimulate further studies of platelet activation directly in native anticoagulated blood/plasma, for both basic and clinical research.
Asunto(s)
Plaquetas/metabolismo , Fibrinógeno/metabolismo , Fluoresceína-5-Isotiocianato , Activación Plaquetaria , Agregación Plaquetaria , Citometría de Flujo , Humanos , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Unión ProteicaRESUMEN
CDC WONDER, an information system developed at the Centers for Disease Control and Prevention (CDC), provides access to 26 text and numeric databases, and special facilities for surveillance, through an architecture developed for public health. We report extensions of the original architecture that allowed us to create a Web version (http:@wonder.cdc.gov).
Asunto(s)
Centers for Disease Control and Prevention, U.S. , Redes de Comunicación de Computadores , Sistemas de Información , Sistemas de Computación , Servicios de Información , Salud Pública , Estados UnidosRESUMEN
This article catalogues some of the Centers for Disease Control and Prevention's (CDC) more important information resource offerings, which make public health information accessible via computer and automated telephone systems and on electronic media (diskette and CD-ROM). We review mechanisms for: (1) finding and retrieving CDC reports, (2) querying CDC's numeric data files, (3) transmitting surveillance and other data files to CDC, (4) exchanging electronic mail with CDC staff, and (5) disseminating state and local public health information and data using CDC tools. Each resource is followed with a section on how to obtain access to these resources.
Asunto(s)
Centers for Disease Control and Prevention, U.S. , Bases de Datos como Asunto , Educación en Salud , Servicios de Información , Sistemas de Información , CD-ROM , Humanos , Internet , Estados UnidosRESUMEN
To strengthen the public health infrastructure, the Centers for Disease Control and Prevention (CDC) initiated the Information Network for Public Health Officials (INPHO). CDC INPHO has three goals: (1) to make communication among public health practitioners throughout the United States easy, (2) to make information accessible, and (3) to make secure data exchange as swift and smooth as contemporary technology will allow. Based on a systems approach to supporting the core functions of public health, CDC INPHO achieves its goals by creating a flexible and user-responsive infrastructure of open communications and information exchange.
Asunto(s)
Centers for Disease Control and Prevention, U.S. , Sistemas de Información , Práctica de Salud Pública , Redes de Comunicación de Computadores , Epidemiología , Reforma de la Atención de Salud , Humanos , Objetivos Organizacionales , Estados UnidosRESUMEN
In the face of disastrous flooding, the Iowa Department of Public Health established the statewide Emergency Computer Communications Network to establish rapid electronic reporting of disaster-related health data, provide e-mail communications among all county health departments, monitor the long-range public health effects of the disaster, and institute a general purpose public health information system in Iowa. Based on software (CDC WONDER/PC) provided by the Centers for Disease Control and Prevention and using standard personal computers and modems, this system has resulted in a 10- to 20-fold increase in surveillance efficiency at the health department, not including time saved by county network participants. It provides a critical disaster assessment capability to the health department but also facilitates the general practice of public health.
Asunto(s)
Redes de Comunicación de Computadores , Desastres , Sistemas de Comunicación entre Servicios de Urgencia , Vigilancia de la Población/métodos , Redes de Comunicación de Computadores/instrumentación , Iowa , Administración en Salud Pública , Gobierno EstatalRESUMEN
Polybrominated biphenyl (PBB), a flame-retardant material, was introduced into the food chain in Michigan in 1973 due to a manufacturing and distribution mistake. Following public concern about the long-term health effects of PBB in humans, a cohort of PBB-exposed Michigan residents was assembled in 1975. We initiated this study to determine the half-life of PBB in human sera and to understand how continued body burden relates to the possible adverse health consequences of PBB exposure. To determine the half-life, eligible persons were selected from the cohort if they had at least two PBB measurements 1 year apart and had an initial level > or = 20 pbb. There were 163 persons who met the criteria with a median PBB level of 45.5 ppb. The estimated half-life is 10.8 years (95% CI, 9.2-14.7 years). The body burden of PBB in exposed persons will decrease only gradually over time. For persons with an initial level of 45.5 ppb of PBB, it will take more than 60 years for their PBB levels to fall below the current level of detection of 1 ppb.