Sistema de vigilancia epidemiológica comunitaria bonis: estado actualy proyecciones futuras / Community epidemiological surveillance system bonis: current status and future projections

El sistema actual de vigilancia epidemiológica en la zona del Centro de Ayuda Mutua y Salud para Todos (CAMSAT) del Bañado Sur, de Asunción, se basa en la búsqueda rutinaria de posibles casos febriles mediante visitas domiciliarias, realizadas por las agentes comunitarias adscritas a la Unidad de Salud Familiar (USF). Cada una de las diezagentes comunitarias de CAMSAT tiene asignada 150 hogares, y los resultados de susvisitas domiciliarias quedan recogidos en planillas que se reportan mediante medios tradicionales (papel, correo interno, fax, etc.) a la DGVS del Ministerio de Salud. La consecuencia de este modo de trabajo es que muchas veces las acciones de bloqueo de la transmisión llegan tarde con el coste social y económico que ello significa. El sistema Bonis introduce la telefonía móvil como elemento catalizador para transformar la búsqueda rutinaria de posibles casos febriles en una acción proactiva, y también la utilización de tecnologías web y bases de datos para el registro de pacientes y su correspondiente seguimiento por el personal sanitario. La utilización de estas tecnologíasde la información y comunicación (TICs) transforman el sistema de vigilancia epidemiológica en un caso de estudio de e-Salud en Paraguay. Se describe el estado actual y proyecciones futuras del sistema de vigilancia epidemiológica comunitaria “Bonis”,que utiliza las TICs para prevenir, alertar, supervisar y controlar la expansión de síndromes febriles en un área de influencia del Hospital Barrio Obrero (HBO), en la Unidad de Atención Primaria en Salud del Centro de Ayuda Mutua y Salud para Todos, Asunción,Paraguay.

The current system of epidemiologic surveillance in the area of Mutual Aid Centre and Health for All (CAMSAT in Spanish) in the “Bañado Sur” in Asuncion is based on routine screening of possible febrile cases through home visits made by community agents fromthe Primary Health Care Unit (USF in Spanish). Each of the ten community agents are assigned to 150 households and the results of these home visits are recorded on sheets that are reported through traditional means (paper, internal mail, fax, etc.) to the DGVSof the Ministry of Health. The consequence of this working system is that often the blocking actions arrive late with the social and economic costs that this implies. The Bonis system uses the mobile phone as a catalyst to transform the routine screening ofpotential feverish cases in a proactive action and the web technology and databases for patient records and appropriate follow-up by health personnel. The use of theseinformation and communication technologies of (ICTs) transforms the Epidemiological Surveillance System in a study case of e-Health in Paraguay. This document describes the current status and future projections of the community epidemiological surveillancesystem Bonis which uses Information and Communication Technologies (ICTs) to prevent, warn, monitor and control the spread of febrile syndromes in a catchment area of Barrio Obrero Hospital (HBO), Unit of Primary Health Care Center Mutual Aid and Health for All, Asuncion, Paraguay.

Telemedicina: metas y aplicaciones / Telemedicine: fine and applicability

La atención sanitaria ha ido variando en las últimas décadas, pasando de una asistenciaenfocada a la enfermedad, a una atención dirigida al ciudadano, más global dondeconceptos como calidad, costes, equidad y continuidad cobran nuevos valores. El enfoquede atención no es sólo tratar cuando la enfermedad llega, sino crear y promover hábitossaludables de vida y prevención de la enfermedad. En la actualidad las tecnologías deinformación y comunicación se han combinado para dar lugar a la telemedicina a fin debrindar asistencia médica a quien la requiera en sitios distantes, se incluye dentro de estecampo a la educación para la salud, salud pública y comunitaria, el desarrollo deprogramas de salud y de prevención, estudios epidemiológicos entre otros. Así mismo, laamplia utilización de Internet ha contribuido a masificar el uso de estos servicios, es asícomo ha nacido un nuevo término conocido como “e-health”, el cual acuña cualquierpráctica de la telemedicina usando esta red. En este artículo se desea incorporarinformación sobre esta disciplina que se encuentra entre medicina y tecnología, la mismapuede proveer un apoyo importante pero su aprovechamiento dependerá de losdiferentes actores envueltos en la implementación.

Implementación de un Sistema de Telemedicina/Telesalud en el Institutode Investigaciones en Ciencias de la Salud (IICS). Estudio Piloto / Implementation of a Telemedicine/Telehealth system at the Institute of

Los procesos de reforma del sector salud orientados hacia una mayor equidad en laprestación de servicios, mayor preocupación por la efectividad y utilidad de lastecnologías para la salud, han contribuido para que la telemedicina sea considerada en lospaíses industrializados y en vías de desarrollo como una herramienta para mejorar laatención de la salud de poblaciones remotas que no tienen acceso a los especialistas. Esteestudio observacional y descriptivo realizado por el Dpto. de Ingeniería Biomédica eImágenes, con el apoyo de la División de Informática del IICS y el Centro Nacional deComputación de la UNA para relevar y analizar las imágenes de 294 pacientes e informestransmitidos por las áreas de ecografía, medicina nuclear y electrocardiografía, incluidosen el proyecto piloto. De los cuales, 254 (86,4 por ciento) correspondieron al servicio de MedicinaNuclear (Centellografía) y completan el grupo los estudios por imágenes ecográficas yelectrocardiográficas. El 49 por ciento fueron gammagrafía de tiroides, 22 por ciento gammagrafías óseas,habiéndose realizado también renogramas isotópicos, gammagrafía hepática, ecografíasde tiroides, abdominales. El tiempo empleado en todo el proceso desde el ingreso delpaciente hasta el informe medico varió en un promedio de 107 a 123 minutos según tipode estudio solicitado.

Influence of density, elasticity, and structure on ultrasound transmission through trabecular bone cylinders.

The aim of this in vitro study is to evaluate the potentiality of quantitative ultrasound (QUS) to separate information on density, elasticity, and structure on specimens of trabecular bone. Fifteen cylinders of spongy bone extracted from equine vertebrae were progressively demineralized and subjected to QUS, micro computed tomography (muCT), Dual energy X-ray absorptiometry (DXA) at various mineralization levels. Eventually all cylinders underwent a compression test to calculate the Young's modulus. Correlation analysis shows that speed of sound (SOS) is strictly associated to bone mineral density (BMD), Young's modulus, and all muCT parameters except for degree of anisotropy (DA). Fast wave amplitude (FWA) is directly correlated with bone surface and total volume ratio (BS/TV) and trabecular separation (Tb Sp), and inversely correlated with trabecular number (Tb N). Because muCT parameters were strictly correlated to BMD and Young's modulus data, partial correlation analysis was performed between SOS, FWA, and structural and elastic data in order to eliminate the effect of density. SOS was significantly correlated to bone volume and total volume ratio (BV/TV), BS/TV, and Young's modulus, and FWA was significantly correlated to Tb Sp only. These results show that SOS is strongly influenced by volumetric mineral bone density and elastic modulus of the specimen, and FWA is mainly affected by trabecular separation independently on density. Therefore, SOS and FWA are able to provide different and complementary information, at least on trabecular bone samples.

Pulsed electromagnetic fields reduce knee osteoarthritic lesion progression in the aged Dunkin Hartley guinea pig.

An experimental in vivo study was performed to test if the effect of Pulsed Electromagnetic Fields (PEMFs) on chondrocyte metabolism and adenosine A2a agonist activity could have a chondroprotective effect on the knee of Dunkin Hartley guinea-pigs of 12 months with spontaneously developed osteoarthritis (OA). After a pilot study, 10 animals were randomly divided into two groups: PEMF-treated group (6 h/day for 3 months) and Sham-treated group. Microradiography and histomorphometry were performed on the entire articular surface of knee joints used in evaluating chondropathy severity, cartilage thickness (CT), cartilage surface Fibrillation Index (FI), subchondral bone plate thickness (SBT) and histomorphometric characteristics of trabecular epiphyseal bone. The PEMF-treated animals showed a significant reduction of chondropathy progression in all knee examined areas (p<0.05). CT was significantly higher (p<0.001) in the medial tibia plateaus of the PEMF-treated group when compared to the Sham-treated group. The highest value of FI was observed in the medial tibia plateau of the Sham-treated group (p<0.05). Significant lower values were observed in SBT of PEMF-treated group in comparison to Sham-treated group in all knee examined areas (p<0.05). The present study results show that PEMFs preserve the morphology of articular cartilage and slower the progression of OA lesions in the knee of aged osteoarthritic guinea pigs. The chondroprotective effect of PEMFs was demonstrated not only in the medial tibial plateau but also on the entire articular surface of the knee.

Influence of bone tissue density and elasticity on ultrasound propagation: an in vitro study.

Ultrasound (US) waves are mechanical vibrations that are applied to a material--bone tissue--in order to study its properties, that is, density, elasticity, and structure. In this study we evaluated in which way density and elasticity of the spongy bone influenced the transmission of 1.25 MHz US pulses. Twelve cylindrical specimens (diameter, 8 mm; height, 5 mm) excised from phalanxes of pig were decalcified with 0.5 M EDTA for different times (0, 2, and 5 days). During these periods, the samples underwent the following investigations: US transmission, density, and elasticity measurements. To assess the homogeneity of decalcification, the cross-sections of some samples were microradiographed. A detailed analysis of the US signal received was performed using velocity, Fourier analysis, and some parameters typical of signal processing technique. A good correlation was found between US velocity and density (r2 = 0.70); a lower correlation was found between velocity and elasticity (r2 = 0.59). If density and elasticity are considered simultaneously, the correlation with the US velocity improves significantly (r2 = 0.84). Fourier analysis enabled us to observe a shift of the main frequency toward lower values as the decalcification process advanced. We also observed that in the regressions weighted for density, US velocity correlated poorly with elasticity (r2 = 0.16), whereas signal processing parameters maintain a good correlation with elasticity (ultrasound peak amplitude [UPA], r2 = 0.48; slope, r2 = 0.62). In this study, it has been observed that when using a signal processing technique to analyze US pulses, it is possible to identify some parameters that are related in different ways to density and to elastic properties of bone. Our results show the potentiality of US technique to separate information on bone density and elasticity that X-ray-based densitometric methods do not provide.

Assessment of bone architecture with ultrasonometry: experimental and clinical experience.

Over the last decade, ultrasound technology has been introduced as a method of analysing bone tissue in clinical practice, and several studies have compared various ultrasound devices with dual-energy X-ray absorptiometry (DXA). Unlike DXA, the ultrasound technique is not limited to the measurement of bone density - it also has the potential to provide information on the mechanical and architectural characteristics of bone. The first generation of ultrasound devices used the speed of sound and attenuation of the ultrasound signal to obtain information on bone mineral content. Second generation ultrasound devices, which analyse the ultrasound signal received, permit the study of bone structure and elasticity, in addition to its mineral content, in both experimental studies and clinical practice. This is accomplished by signal processing analysis, the study of backscattering and the application of Biot's theory. This approach to the study of bone tissue represents the future for the development of ultrasound technology for use in clinical practice.

Histomorphometric study on the osteocyte lacuno-canalicular network in animals of different species. II. Parallel-fibered and lamellar bones.

The shape, size and density of osteocyte lacunae in parallel-fibered and lamellar bone were histomorphometrically analyzed in relation to the organization of the collagen fiber texture and the animal species (frog, sheep, dog, bovine, horse and man). The following parameters were measured under the light microscope (LM) by a computer-assisted image analyzer: 1) shape, size and distribution of osteocyte lacunae; 2) osteocyte lacuno-canalicular density. In close agreement with our previous studies, which includes woven bone, it resulted that in all animals (even in frog) osteocyte lacunae have a rounded globous shape in woven bone and an oval shape in both parallel-fibered and lamellar bone; in the latter, however, they are more flattened, only located in loose lamellae and thus regularly distributed in rows. Osteocyte lacunar density is higher in woven-fibered, intermediate in parallel-fibered and lower in lamellar bone, whereas no correlation seems to exist with the animal species. In conclusion, these results suggest that osteocyte shape, size and density seem to depend mainly on collagen fiber texture rather than on the animal species. The role of osteocyte-recruitment on the spatial organization of collagen fibers in bone tissues is discussed.

Effects of essential amino acids and lactose on bony fractures and defects in rabbits: a preliminary histomorphometric study.

An experimental study was performed in order to test the possibility of improving bone repair with the administration of a drug (Calciofix, Farmaceutici Damor SpA, Naples, Italy) containing essential amino acids and lactose. Fifty rabbits were submitted to an open transversal fracture of the left fibula and to a right femoral condyle defect. They were left untreated or treated daily with the drug orally and were divided into subgroups depending on the experimental time: 15, 30, 40, 50, 60 days. Histomorphometric data showed a significantly faster healing rate in treated animals compared with untreated ones. Firstly, on day 30 there was a significantly larger amount of cartilage in the control bone callus (P < 0.01). On day 50 a significant difference existed between trabecular and lacunar percentages in the two subgroups (P < 0.0005). At 60 days no significant differences were observed, but bony trabeculae had become more oriented parallel to the long axis of the bone in treated animals. Secondly, after 15 days the defect area was significantly smaller in treated animals than in the untreated ones (P < 0.01). At 30 and 40 days, respectively, significant differences existed between the two subgroups in connective tissue and mature bone percentages (P < 0.01 and P < 0.001). Our results seem to demonstrate that the drug significantly accelerates the rate of bone formation in fractures and bone defects in rabbits.

A reabsorbable tubular chamber for the treatment of large diaphyseal bone defects. Experimental study in rabbits.

Twenty-five rabbits were used to test the healing of diaphyseal defects by means of a reabsorbable tubular chamber. In 20 animals a 10 mm gap was created in the left radius and bridged with a poly-L-lactide chamber (experimental side). The same defect was created on the right radius, remaining untreated (control side). In the remaining 5 animals, the right radius was left intact and they were used only for biomechanical tests at 12 months. X-rays and histomorphometry showed no bone repair at the control side while the inner surface of the chamber was progressively lined by neoformed bone (75% of the normal cortical thickness). Biomechanical data demonstrated that elastic modulus and ultimate stress were not significantly different in both experimental and intact radii. The chamber, by preventing the passage of soft tissues and creating a close space for intrinsic repair factors, seems to be a suitable device for the repair of long bone defects.

Histomorphometric study on the osteocyte lacuno-canalicular network in animals of different species. I. Woven-fibered and parallel-fibered bones.

A comparative histomorphometric study was carried out on the extension of lacunocanalicular network in two types of bone tissue (woven and parallel-fibered) in shaft bones of various animals (Frog, Chicken, Rabbit, Bovine, Horse, Dog, Man), with the aim to understand whether the distribution of osteocyte network is related to the organization of the collagen fibers or to the animal species. By means of a light microscope (LM) connected with an image-Analyser the following parameters were measured: 1) the cross-sectional area and the volume of osteocyte lacunae; 2) the osteocyte density; 3) the number of canaliculi departing both from the whole outline of the sectional area of osteocyte lacunae and, in the parallel-fibered osteons only (both with LM and SEM), from their two opposite walls, i.e., from the wall facing the Haversian canal (vascular wall) and from that facing the cement line (peripheral wall). In all the animals studied the size and density of osteocyte lacunae as well as the extension of the canalicular network proved to be markedly higher in woven than in parallel-fibered bone, whereas no relation with the species was found. These findings suggest that the function of osteocyte is mainly involved in the regulation of skeletal homeostasis, as discussed in the present paper.

Histomorphological and chemico-physical analyses of the mineral matrix of micropetrotic human bone.

Micropetrotic areas of human bone were analyzed with reference to their distance from blood vessels and to the age of the subjects. Undecalcified bone sections were treated with various solvent, soaking and etching substances to establish the nature of the material occluding the osteocytic canalicular cavities, and were examined by means of microradiographic and microdurimetric methods and X-ray microanalysis to evaluate the degree of mineralization in the bone matrix. Since it was only after strong etching with HCl that the canalicular network became visible under light and scanning electron microscopy, it is clear that the debris filling the canalicular network consists almost entirely of mineral substance. The degree of mineralization of micropetrotic bone is high because it is always a more mature type of bone, but the mineral content of the matrix and the Ca/P ratio do not differ significantly from those of neighbouring bone where the canalicular network is fully pervious.

Pathways of transmission of ultrasound energy through the distal metaphysis of the second phalanx of pigs: an in vitro study.

Ultrasound (US) has been studied by several researchers to assess its possible use in screening for osteoporosis; among other sites the phalanxes have been proposed as a possible site for investigation with US. In the present experimental work we studied the morphostructural characteristics of the second phalanx of the pig; then, in vitro, we investigated the behaviour of an ultrasound signal at 1.25 MHz crossing the distal metaphysis of the second phalanx. In particular, we studied the effects of milling or drilling on US velocity, and on the energy and shape of the signal generated by the US at the receiving probe. We demonstrated that the US velocity decreases by an average of 496 m/s (-21%) when axial perforations are made in the central marrow. A decrease is also noted in the number of peaks, and the normalized energy of the US signal received falls on average by 11.3 mV microseconds (-84%). The characteristics of the signal at the receiving probe can be broadly reconstituted if, after extensive drilling, the bone cavity is filled with polymerized styrene resin. In contrast, if phalanx milling is performed to remove the outermost bone tissue, the normalized energy increases by 15.5 mV microseconds (+84%) and the velocity of US increases by 163 m/s (+7%). It was also noted that the complexity of the signal received (i.e. number of peaks) and the signal normalized energy depend on the integrity of the bone structures traversed. The results reported here provide useful indications for interpreting the findings of clinical investigations with US, most specifically those performed on the phalanx of the hand.

Pulsed magnetic fields improve osteoblast activity during the repair of an experimental osseous defect.

The influence of pulsed low-frequency electromagnetic fields (PEMFs) on bone formation was investigated in studies of the healing process of transcortical holes, bored at the diaphyseal region of metacarpal bones of six adult horses, exposed for 30 days to PEMFs (28 G peak amplitude, 1.3 ms rise time, and 75 Hz repetition rate). A pair of Helmholtz coils, continuously powered by a pulse generator, was applied for 30 days to the left metacarpal bone, through which two holes, of equal diameter and depth, had been bored at the diaphyseal region. Two equal holes, bored at the same level in the right metacarpal and surrounded by an inactive pair of Helmholtz coils, were used as controls. All horses were given an intravenous injection of 25-30 mg/kg of tetracycline chloride on the 15th and again on the 25th day after the operation and were killed 5 days later. The histomorphometric analysis indicated that both the amount of bone formed during 30 days and the mineral apposition rate during 10 days (deduced from the interval between the two tetracycline labels) were significantly greater (p < 0.01 and p < 0.0001, respectively) in the PEMF-treated holes than in the controls. As did a previous investigation, these preliminary findings indicate that PEMFs at low frequency not only stimulate bone repair but also seem to improve the osteogenic phase of the healing process, at least in our experimental conditions.

Electromagnetic stimulation of bone repair: a histomorphometric study.

The effect of pulsing electromagnetic fields (PEMFs) on bone repair was studied in principal metacarpal bones of eight adult male horses: Six horses were treated with PEMFs, and two horses were untreated. In treated horses, Helmholtz coils were applied during a 60-day period to the left metacarpal bones, bored with eight holes of equal diameter and depth, from the middiaphysis toward the distal metaphysis. Eight equal holes bored in the right metacarpal, surrounded by unactivated Helmholtz coils, were taken as controls. The two untreated horses were taken as additional control. The results of computer-assisted histomorphometric analysis indicate that (a) in diaphyseal levels, the amount of bone formed during 60 days is significantly greater (p less than 0.01) in PEMF-treated holes than in contralateral ones and those in control horses; (b) in metaphyseal levels, PEMF-treated holes are sometimes more closed, sometimes less, as compared with contralateral holes and those in control horses; in any case the statistical analysis indicates that the symmetry in the rate of hole repair, found between the two antimeres of control horses, is not appreciable at metaphyseal levels also; (c) there was no statistically significant difference between untreated holes in PEMF-treated horses and holes in control horses, neither at diaphyseal nor at metaphyseal levels. These preliminary findings indicate that PEMFs at low frequency influence the process of bone repair on both diaphysis and metaphysis, and seem to improve the process of bone repair in skeletal regions normally having a lower osteogenetic activity, i.e., in diaphyses as against metaphyses.

A light and scanning electron microscopic study of osteocyte activity in calcium-deficient rats.

The material herein is an extension of an earlier study of osteocyte lacunae in calcium-deficient rats, utilizing morphometric measurements in undecalcified bone sections and scanning electron microscopy. The results confirm our earlier finding that bone resorption resulting from a low-calcium diet is not accompanied by osteocytic resorption.

Activity of osteoclasts and osteocytes in compact human bone at various ages, both with and without osteoporosis.

As part of a programme of research designed to assess the respective roles of osteoclasts and osteocytes in the processes of bone resorption, the metabolic activity of these cells was evaluated indirectly by a morphometric method in the compact bone of human tibias from subjects of various ages, both normal and those affected by osteoporosis. Statistical analysis of the quantitative data was in agreement with the microradiographic examination of the sections, and showed that whereas the intensity of osteoclastic resorption varied in the various subjects according to age, periosteocytic osteolysis--in the classical sense of a phenomenon involving widening of the lacunae detectable with the optical microscope--did not occur in compact bone whether it was normal or highly porotic.

Morphometric analysis of osteoblast dynamics in the chick embryo tibia.

Structure and size of the osteoblasts have been analyzed during growth of the tibial diaphyses in chick embryos from 10 days incubation until hatching. Statistical analyses of the results indicate that both size and density of the osteoblasts gradually decrease from the subperiosteal towards the endosteal regions of the shaft; the osteoblast secretory territory, on the other hand increases. These structural changes of the osteoblasts, which appear to be related to differences of the appositional growth rate, seem to derive mainly from structural modifications of differentiated osteoblasts rather than from differentiation of new osteoblasts, of progressively smaller size, from osteoprogenitor cells. The data reported in this paper compared with those in previous investigations indicate that the size of the osteoblasts does not significantly differ in animals of different species.