Showing papers by "Rio de Janeiro State University published in 1989"

Modeling malaria vaccines. II: Population effects of stage-specific malaria vaccines dependent on natural boosting.

Abstract: Population effects of malaria vaccination programs will depend on the stage specificity of the vaccine, its duration of effectiveness, whether it is responsive to natural boosting, the proportion vaccinated, and the preexisting endemic conditions. This paper develops models of infection-blocking (sporozoite), disease-modifying (merozoite), and transmission-blocking (gametic) vaccines. It explores numerically their different effects on prevalence of infection and disease when utilized in different types of immunization programs at various levels of coverage. Simulations show that possible qualitative consequences of malaria vaccination programs include decreased prevalence of infection and disease and decreased prevalence of infection without a corresponding decrease in prevalence of disease. Epidemics, either one-time or cyclical, could occur. These effects could be accompanied by changes in the age distribution of disease. Finally, vaccination could contribute to elimination of transmission. The duration of effectiveness of the malaria vaccine relative to the duration of natural immunity could have important consequences for the unvaccinated. The problem of predicting a threshold for elimination of transmission is discussed.

Modeling malaria vaccines. I: New uses for old ideas.

Abstract: Starting from a modification of the model of malaria transmission developed for the Garki project, this paper develops a model containing variables relevant to the simulation of malaria vaccination programs. Modifications include (1) integration of maintenance of immunity dependent on boosting and the possibility of loss immunity; (2) introduction of a boosting factor distinct from susceptibility to infection; (3) reinterpretation of the epidemiological compartments of positive immunes and nonimmunes in terms of severity of disease rather than just infection; (4) interpretation of the different stage-specific levels of immunity; (5) discrimination between different susceptibilities for the immune and nonimmune classes; (6) reformulation of the expression for acquisition of immunity to be biologically more acceptable. Simulations using the Garki model, Nedelman's modification of it, and our Basic model compare the similarities and differences in the predictive behavior of the models. Simulations using the Basic model reproduce observed periodic fluctuations of malaria attributed to the interplay of transmission-blocking immunity and loss of immunity in the absence of boosting in areas of unstable malaria transmission.

An endocytic process in HEp-2 cells induced by enteropathogenic Escherichia coli.

Abstract: Infection of HEp-2 cells by enteropathogenic Escherichia coli (EPEC) was examined by transmission and scanning electronmicroscopy. EPEC strains of serogroups O111:K58 and O55:K59 recently isolated from human patients did not exhibit enterotoxic activity, as judged by the Vero-cell and suckling-mouse assays, or invasive ability as judged by the Sereny test. These strains attached to and penetrated HEp-2 cells. Transmission electronmicroscopy showed bacteria in close contact with cell membranes 15 min after infection; later, intense swelling and budding of membranes and penetration of EPEC into the cell cytoplasm occurred. Intracellular bacteria were enclosed in membrane-bound vacuoles in the cell cytoplasm underlying localised adherence sites observed by light microscopy. Scanning electronmicroscopy showed morphologically altered membranes only at the sites of bacterial attachment. Bacteria inactivated by ultraviolet light were not internalised and cytochalasin B (greater than or equal to 10 mg/L) markedly inhibited uptake. These observations suggest that penetration of EPEC into HEp-2 cells occurs by an endocytic process in metabolically active bacteria.

Adherence of Pseudomonas aeruginosa to respiratory epithelium and the effect of leucocyte elastase.

Abstract: The tracheobronchial secretions from patients with cystic fibrosis often contain high amounts of free proteases. To evaluate whether human leucocyte elastase (HLE) can favour the persistence of bacterial airways infection, we exposed the frog palate mucosa to HLE and then to radiolabelled Pseudomonas aeruginosa and followed the sequence of events by scanning electronmicroscopy. In response to HLE there was a marked outpouring of mucus and a desquamation of the epithelium. P. aeruginosa was shown to adhere to recently secreted granules of mucus and to the exposed submucosal underlying connective tissues. For the eight different bacterial strains studied, a significative adherence to HLE-injured mucosa was observed only in strains that possessed internal haemagglutinating activity. Neither the presence of fimbriae, nor of the mucoid exopolysaccharide, nor of the bacterial surface haemagglutinating activity could be related to adherence of P. aeruginosa to the injured mucosa. These results support the hypothesis that HLE enhances bacterial infection of the respiratory mucosa both by inducing mucus hypersecretion and by exposing receptors to the microbial adhesins. It is also suggested that P. aeruginosa internal lectins may be implicated in adherence to host tissues.

The significance of physical development on the blood pressure curve of children between 6 and 9 years of age and its relationship with familial aggregation.

Abstract: Arterial blood pressure values of 3109 children between 6 and 9 years of age in the city of Rio de Janeiro were analysed according to low, medium and high socio-economic levels. At medium and high socio-economic levels, arterial pressures, weight and height were higher than those observed in children of a lower socio-economic level. Blood pressure was best correlated to body weight. The aggregation of arterial pressure, weight and height was compared between family members of children with percentiles below 50 and above 90. Systolic blood pressure and weight were significantly lower in family members with a percentile below 50. We conclude that there is a need for a long-term follow-up of these children and their families, in order to improve our knowledge of the mechanisms involved in the origin of arterial hypertension.

Enteric parasites and HIV infection: occurrence in AIDS patients in Rio de Janeiro, Brazil.

Abstract: The occurrence of intestinal parasites, its relation with the transmission mechanism of HIV, and the clinical state of the AIDS patients, were analyzed in 99 Group IV patients (CDC, 1986), treated at "Hospital Universitario Pedro Ernesto" (HUPE), between 1986 and 1988. The group consisted of 79 (79.8%) patients whose HIV transmission mechanism took place through sexual contact and of 16 (20.2%) who were infected through blood. Feces samples from each patient were examined by four distincts methods (Faust et al, Kato-Katz, Baermann-Moraes and Baxby et al.). The moste occuring parasites were: Cryptosporidium sp., Entamoeba coli and Endolimax nana (18.2%), Strongyloides stercoralis and Giardia lambia (15.2%). E. histolytica and/or E. hartmanni (13.1%), Ascaris lumbricoides (11.1%) and Isospora belli (10.1%). Furthermore, 74.7% of the patients carried at least one species. Intestinal parasites were found in 78.5% of the patients who acquired the HIV through sexual intercourse and in 56,3% of those infected by blood contamination. The difference, was not statistically significant (p > 0.05). In the group under study, the increase of the occurrence of parasitc infections does not seem to depend on the acquisiton of HIV through sexual contact. It appears that in developing countries, the dependancy is more related to the classic mechanisms of parasites transmission and its endemicity.

Astroglial differentiation in the opossum superior colliculus.

Abstract: Glial markers, namely, vimentin, glial fibrillary acidic protein (GFAP), and glycogen, as well as accumulation of axon-borne horseradish peroxidase (HRP), were used to visualize radial glial cells in the developing opossum superior colliculus (SC) and to follow changes in young astrocytes of the superficial layers. Vimentin, GFAP, and glycogen are relatively abundant in elements of the median ventricular formation (MVF), which persists at least as late as weaning time, i.e., postconception day 103, postnatal day 90 (PND90). Radial profiles and end-feet in the remaining collicular sectors (main radial system, MRS) are also vimentin-positive but show little or no glycogen or anti-GFAP staining. The numeric density of MRS profiles is very high at the final stages of neuronal migration (PND12) but falls to vestigial numbers by PND 56–60. Antivimentin staining and filling of MRS profiles by axon-borne HRP disappear in parallel. Before total regression of MRS profiles, young astrocytes of the superficial gray layer exhibit a transiently high GFAP expression that is not found in those of the subjacent layers. The results suggest that (1) radial glia at or near the collicular midline are well equipped for a mechanical supportive role, and their abundant glycogen accumulation may reflect their eventual transformation in cells with high glycolytic metabolism, including tanycytes; (2) in most collicular sectors, some radial glia cells persist for long periods after cessation of neuronal migration and may interact with afferent fibers coursing through the superficial neuropil; (3) radially oriented astrocytes of the superficial gray layer exhibit a transiently high GFAP expression that is temporally correlated with late transformations of the retinocollicular projections.

Morphometry of the kidney. Applied study in urology and imaging

Abstract: A morphometric study was made on 100 human kidneys obtained by necropsies from 50 cadavers without renal pathology and ranging in age from 16 of 60 years (32.0 +/- 12.1 years). The results of the renal measures showed the following averages: length (right kidney 10.97 cm; left kidney = 11.21.cm), Width of the superior pole (right kidney = 6.40 cm; left kidney = 6.48 cm), width of the inferior pole (right kidney = 5.59 cm; left kidney = 5.39 cm), thickness (right kidney = 3.21 cm; left kidney = 3.37 cm). Left kidney presented usually greater length, greater width and greater thickness than right kidney. There are positive relations between several measures of the renal morphometry. Allometric method was used in order to study the correlation renal length vs body length and to make the curves.

Morphometry of terminal hepatic veins. 2. Follow up in chronically alcohol-fed baboons.

Abstract: Alcohol induced perivenular fibrosis of terminal hepatic veins (THV) is claimed to be a precursor lesion leading to fibrosis development in man and baboon. The nature and significance of the THV lesions found in four baboons chronically fed with alcohol were studied in liver biopsies obtained during a three year period. The surface of THV wall and the number of mesenchymal cells were assessed with a semi-automatic image analyser. Histologically, THV were characterized as (a) phlebitic, in the presence of an inflammatory cell infiltrate involving the venous wall; (b) oedematous, when the connective tissue of the THV wall was disrupted or dissociated and (c) fibrotic, when perivenular scarring appeared as an increased rim. These lesions were present simultaneously and their intensity and distribution were independent of the duration of alcohol intoxication. Morphometric data obtained from these THV confirmed the thickening of the THV wall (WS/IS in: oedematous 1.05±0.36; phlebitic 1.65±1.04; fibrotic 1.47±0.36); and revealed an increased number of mesenchymal cells in fibrotic (439 μm2/cell;p<0.01) and in phlebitic THV (510 μm2/cell;p<0.05). A constant relationship was found between phlebitis and the presence of inflammatory infiltrate within the hepatic acini. Fibrotic THV was a less frequent finding and the lesion disappeared in the sequential biopsies of one of the baboons. In conclusion, THV lesions were heterogeneous and the collagen deposition in the THV wall was potentially reversible during the three year alcohol intoxication period, regardless the inflammatory reaction and, thus, did not indicate early irreversible hapatic fibrosis.

Proposta metodológica para inquérito domiciliar com populações idosas em um centro urbano do Estado do Rio de Janeiro (Brasil)

Abstract: The methodology used by a project being carried out at the Institute of Social Medicine, Rio de Janeiro, concerning the epidemiology of the elderly and the stages of the community survey are presented. The sampling methods and the steps of the enumerator process are also detailed.

Exact solutions in brans-dicke theory: A dynamical system approach

Abstract: A method is furnished for constructing isotropic and homogeneous solutions in Brans-Dicke theory based on the analysis of the dynamical system formed by the field equations. Large classes of solutions found in the literature are recovered and shown to be special cases of those generated by this method.

Qualitative analysis of cosmological models in brans-dicke theory

Abstract: Isotropic and homogeneous cosmological models with a perfect fluid cource in Brans-Dicke theory are investigated from the point of view of dynamical system theory.

O método da redescoberta orientada e a criação e desenvolvimento de um laboratório de acústica para o curso de Física

Abstract: Neste artigo e discutido e mostrado o texto do curso, o qual inclui a parte experimental, formando um so corpo E feito um historico do processo de criacao do laboratorio, sendo ponto importante a busca de equipamento ja existente na Universidade Sao levantadas e analisadas as principais dificuldades encontradas pelos alunos, frente a cada pratica E apresentado um balanco do que ja foi feito, bem como os planos futuros, tanto em relacao as instalacoes quanto a inclusao de novos topicos no curso

Allometric study of renal growth in human fetuses.

Abstract: Human renal growth was studied in 60 kidneys (30 staged fetuses, ranging in age from 10 to 38 weeks post conception, WPC). The kidneys were measured for greatest length (L) and weight (W) and the data correlated to the gestational age by using the allometric method (Y = bXK). The equations of the growth curves are presented in the text.

On the morphology of Laevapex vazi n. sp. from Brazil (Mollusca: Pulmonata: Basommatophora: Ancylidae)

Abstract: A description of Laevapex vazi n. sp. based on 8 specimens collectec in Ourinhos, state of Sao Paulo, is presented. Shell thin, diaphanous, with a light brown periostracum and moderately elliptical opening. Apex not pointed, smooth, situated on the right posterior region of the shell, inclined to the right often reaching the edge of the shell or extending beyond it. Concentric lines clearly visible; radial striation not visible or when perceptible very thin, here and there. Ratios: shell width/shell lenght = 0,60 - 0,67 (mean = 0,63); shell height/shell length = 0,50 - 0,61 (mean = 0,55); shell height/shell width = 0,33 - 0,40 (mean = 0,35). Body of normal ancylid type; mantle pigmentation concentrated on the left side; three muscles are seen: a round posterior one on the left side, an elliptical muscle on the right anterior side and an almost almond-shaped one on the left anterior side. Tentacles with a medium core of black pigment. Pseudobranch two-lobed and folded, the dorsal lobe smaller than the vetral one. Ovotestis with 20 unbranched diverticula, around a short collecting canal. Ovispermiduct with an enlargement with several round outpocketings constituting the seminal vesicle. Carrefour as a round sac. Albumen gland almost cylindrical with several acinous diverticula. Elongated nidamental gland continous with the galndular wall of the uterus; uterus flattened and thin-walled. Spermathecal body almost rounded. Pear-shaped prostate without diverticula. Penial complex without flagellum but with well-developed ultra-penis and penis. Jaw horseshoe shaped. Radular forma 20.1.20; raquidian tooth quadricuspid, asymmetrical. The genus Laevapex Walker, 1903 is recorded for the first time in Brazil. It is easily distinguished from South American Gundlachia Pfeiffer, 1849 by its penial complex. Laevapex vazi is dedicated to Dr. Jorge Faria Vaz, from SUCEN-SP, who have been sent to me the specimens.

Quasi-maxwellian fields in riemann-cartan spacetime

Abstract: The electric part of the Weyl conformai curvature tensor is computed for a static, cylindrically symmetric cluster in Einstein-Cartan (EC) theory.

Relative growth of the human metacarpals in the prenatal period: anatomic basis of preventive surgery for congenital deformities of the hand.

Abstract: Twenty right metacarpal bones of Brazilian fetuses (ranging from 17 to 35 weeks post-conception) were studied by the allometric method to define the pattern of metacarpal growth. The metacarpal measurements analysed were their maximum length (ML), ossified shaft length (OSL) and midshaft breadth (MSB). These data were related to crown-rump length and the metacarpal weight to fetal weight. The increase in metacarpal measurements showed an allometric positive coefficient (k), highest in the OSL. The ML growth followed an axo-marginal pattern. The 3rd metacarpal showed the highest MSBk coefficient. The metacarpal weight showed the highest correlation coefficient (r) to the fetal data. These findings are important to the knowledge of human hand growth and are the basis of preventive surgery for congenital deformities of the hand.

Atrioventricular valves development in human heart: the Paris embryological collection revisited.

Abstract: 29 human embryos staging from stage 15 to stage 23 (post-somitic period, collection of the UER Biomedicale des Saints-Peres, Universite Rene Descartes Paris V) have been studied. The most important morphological events of the atrioventricular valves development have been reinvestigated and photographed. This is a complementary information about cardiac development analysing this french collection of human embryos (Mandarim-de-Lacerda, in press). At stage 15, we can observe the gelatinous reticulum well organized when cardiac valves will become established; progressively the fused endocardial cushions and right and left lateral cushions encircle the atrioventricular channels indicating the site of the tricuspid valves. These cushions, however, have a temporary influence being replaced gradually by atrial and ventricular myocardium. At stage 23, the heart presents a complete atrioventricular valvular structure.

Electron paramagnetic resonance studies of irradiated single crystals of cesium chloride doped with nickel cyanide complexes

Abstract: The EPR spectra of X-ray irradiated single crystals of CsCl doped with nickel cyanide complexes are studied at X-band and 77 K. The measured g values and spin densities indicate the formation of two mono-chlorinated oxidized species. Bei 77 K werden im X-Band die EPR-Spektren von rontgenbestrahlten und mit Nickelzyanidkomplexen dotierten CsCl-Einkristallen untersucht. Die gemessenen g-Werte und die Spindichten weisen auf die Bildung von zwei mono-chlorierten oxidierten Spezies hin.

Estudo da suscetibilidade "in vitro" a um novo antimicrobiano (IMIPENEM) de patógenos isolados de pacientes hospitalares em vários centros

Abstract: O imipenem e um novo antibiotico Beta lactâmico, carbapenemico, altamente potente e com amplo espectro de atividade antimicrobiana Com intuito de comprovar a eficacia "in vitro" deste farmaco em patogenos mais frequentes em nosso meio, descrevem os autores, os resultados das provas de suscetibilidade por discos e/ou a correspondencia por provas de diluicao para determinacao da concentracao inibitoria minima (CIM) em 1230 cepas compreendendo 41 diferentes especies bacterianas recem-isoladas, principalmente de pacientes hospitalares em 5 diferentes centros medicos de Sao Paulo, Rio de Janeiro e Salvador Nossos resultados preliminares com o antibiotico, em fase final de experimentacao clinica e laboratorial, em nosso meio, foram muito promissores, com 9679% de cepas suscetiveis pela prova do disco (10 μg de imipenem) e 92,31% de correspondencia pela determinacao do CIM (concentracoes de ate 4μg/ml) Das 9 especies bacterianas mais frequentemente isoladas, correspondendo a 1008 (82%) das 1230 cepas de nosso material, as sensibilidades pela prova do disco foram de 99% (E coli), 93% (Pseudomonas aeruginosas), 87% (Staphylococcus aureus), 100% (Klebsiella pneumoniae), 98% (Klebsiella sp) e 100% (Streptococcus faecalis) com boa correspondencia pela determinacao do CIM ate 8μg/ml; e 100% para o anaerobio Bacteroides sp (CIM ate 4μg/ml) Ressaltam os autores a eficacia "in vitro" contra patogenos hospitalares que apresentam elevados indices de resistencia a grande maioria de antibioticos como o Pseudomonas aeruginosa e para anaerobios, notadamente o Bacteroides sp

Pore pressure predictions in finite element analysis

Abstract: Many of the existing pore pressure models for FEM analysis are limited either to cases where the pore pressure component produced by the shearing stress is neglected (usually restricted to static analysis) or where the component produced by the mean confining stress is disregarded (usually restricted to cyclic loading, as in earthquake and offshore engineering). A pore pressure model including the simultaneous effects of shear and mean confining stresses is presented in this paper. The model is simple and applicable to static as well as cyclic loading. The conceptual relationship between strains and pore pressure is well recognized in soil mechanics; however, it is difficult to determine the strains by FEM with the necessary accuracy to ensure satisfactory pore pressure predictions, mainly in the range of strains where the concepts of stress path are best applicable. To overcome this limitation, the proposed technique introduces a pore pressure function, to be coupled to a potential and a loading function in an elastic—plastic constitutive model. For simplicity, it is assumed that the pore pressure response can be satisfactorily represented by a path dependent calibrating function determined to fit experiments over a given range of confining pressures. This procedure allows the independent determination of the pore pressure increment before the iterative elastic—plastic procedure is activated, thus supplying the constitutive model directly with the appropriate direction and magnitude of the effective stress increment. The advantages of this procedure during undrained loading are presented in the text.

Labelling of the platyhelminth Dugesia tigrina with 99mtechnetium.

Abstract: The study of the labelling of planaria with 99mTc shows that the incorporation of radioactivity in this platyhelminth increases with an increase in SnCl2 concentration from 0.13 to 1.3 microM, reaching a plateau in the range of 1.3-130 microM then decreasing with 1300 microM. At concentrations of 1.3 and 13 microM SnCl2, a stronger binding of 99mTc was obtained. The biological viability of the labelled planaria was not altered when the described methodology was used. The advantage of this new labelling technique is that it is possible to obtain a platyhelminth preparation labelled with a radionuclide that is very cheap, is easily available and is a gamma emitter with a photon energy of 140 keV.