Effect of abutment`s height and framework alloy on the load distribution of mandibular cantilevered implant-supported prosthesis

In cantilevered implant-supported complete prosthesis, the abutments` different heights represent different lever arms to which the abutments are subjected resulting in deformation of the components, which in turn transmit the load to the adjacent bone. The purpose of this in vitro study was to quantitatively assess the deformation of abutments of different heights in mandibular cantilevered implant-supported complete prosthesis. A circular steel master cast with five perforations containing implant replicas (O3.75 mm) was used. Two groups were formed according to the types of alloy of the framework (CoCr or PdAg). Three frameworks were made for each group to be tested with 4, 5.5 and 7 mm abutments. A 100 N load was applied at a point 15 mm distal to the center of the terminal implant. Readings of the deformations generated on the mesial and distal aspects of the abutments were obtained with the use of strain gauges. Deformation caused by tension and compression was observed in all specimens with the terminal abutment taking most of the load. An increase in deformation was observed in the terminal abutment as the height was increased. The use of an alloy of higher elastic modulus (CoCr) also caused the abutment deformation to increase. Abutment`s height and framework alloy influence the deformation of abutments of mandibular cantilevered implant-supported prosthesis. To cite this article:Suedam V, Capello SouzaEA, Moura MS, Jacques LB, Rubo JH. Effect of abutment`s height and framework alloy on the load distribution of mandibular cantilevered implant-supported prosthesis. Clin. Oral Impl. Res. 20, 2009; 196-200.doi: 10.1111/j.1600-0501.2008.01609.x.

The strain-driven pyrochlore to "defect fluorite" phase transition in rare earth sesquioxide stabilized cubic zirconias

The relationship between the ordering characteristic of the pyrochlore structure type and that characteristic of the defect fluorite structure type (immediately on either side of two phase regions separating the two structure types) in a range of rare eath sesquioxide stabilized cubic zirconias is investigated via electron diffraction and imaging. Systematic structural change as a function of composition and relative size of the constituent metal ions is highlighted and a multi-q to single-q = 1/2 [111]* model proposed for the observed pyrochlore to defect fluorite phase transition. Strain introduced into the close-packed {111} metal ion planes of the defect fluorite average structure by the local cation and oxygen vacancy distribution is pointed to as the likely origin of the observed behavior. (C) 2001 Academic Press

Distribution of virulence markers in clinical and environmental Vibrio cholerae non-O1/non-O139 strains isolated in Brazil from 1991 to 2000

One hundred seventy nine Vibrio cholerae non-O1/non-O139 strains from clinical and different environmental sources isolated in Brazil from 1991 to 2000 were serogrouped and screened for the presence of four different virulence factors. The Random Amplification of Polymorphic DNA (RAPD) technique was used to evaluate the genetic relatedness among strains. Fifty-four different serogroups were identified and V. cholerae O26 was the most common (7.8%). PCR analysis for three genes (ctxA, zot, ace) located of the CTX genetic element and one gene (tcpA) located on the VPI pathogenicity island showed that 27 strains harbored one or more of these genes. Eight (4.5%) strains possessed the complete set of CTX element genes and all but one of these belonged to the O26 serogroup suggesting that V. cholerae O26 has the potential to be an epidemic strain. The RAPD profiles revealed a wide variability among strains and no genetic correlation was observed.

Lectin receptors distribution in the surface membrane of Trypanosoma cruzi blood forms collected from mice submitted to specific treatment

The author investigated the distribution of lectin receptors on Trypanosoma cruzi blood forms collected from mice inoculated with, respectively, the drug-resistant and drug-sensitive strains VL-10 and CL, and treated with the two standard active nitroheterocyclic compounds nifurtimox and benznidazole used for treatment of human Chagas' disease. Blood trypomastigotes purified in Fycoll-Hypaque were incubated with fluorescein-labelled lectins Con A, WGA, EE, WFA, TPA and PNA and then microscopically examined. Neither qualitative or quantitative differences in the fluorescence intensity could be detected between parasites from VL-10 and CL strains submitted or not to treatment. The results suggest that both strains do not differ in their surface membrane carbohydrate moieties. Moreover, the rapid clearance of blood forms the drug-sensitive strain in animals treated with singlo doses of both compounds is not likely to depend on membrane alterations expressed by changes in the carbohydrate components. furthermore, resistance or sensitivity to drugs is not apparently related to carbohydrate distribution on T. cruzi blood forms.

Recent studies on Schistosoma intercalatum: taxonomic status, puzzling distribution and transmission foci revisited

Schistosoma intercalatum, which causes human rectal schistosomiasis in Africa, still presents a great interest for its imprecise taxonomic status and its puzzling distribution in Africa. Two geographically isolated strains of S. intercalatum are recognized, the Lower Guinea strain and the Congo strain, which differ from each other in a number of morphological, biological and biochemical characteristics. Recent molecular data using RAPD markers indicate high divergence between the two strains, with values of Nei and Li's similarity indice allowing recognition of two genetically distinct taxa: experiments on pre- and post-isolating mechanisms are in progress in order to re-evaluate the taxonomic status of this polytypic species. With regard to its geographical distribution, S. intercalatum is characterized by the existence of two stable endemic areas (localized in Lower Guinea and North East of Democratic Republic of Congo) which correspond to the historical areas of species discovery, and the emergence during the last 15 years of new foci of the Lower Guinea strain outside previously known endemic areas. The absence of local adaptation of the Lower Guinea strain to its intermediate host, supported by experimental studies, may help to facilitate the spread of this strain. Nevertheless, the present restricted distribution of this species remains puzzling, because its potential snail hosts (bulinids) are widely distributed throughout much of Africa. Recent experimental and epidemiological studies suggest that interspecific sexual interactions between human schistosomes could have a role in limiting the distribution of S. intercalatum: the competitive sexual processes acting among human schistosomes show that S. haematobium and S. mansoni are always competitively dominant over S. intercalatum. These epidemiological observations lead the authors to distinguish three kinds of transmission foci for S. intercalatum.

Experimental infection of dogs with a Brazilian strain of Rickettsia rickettsii: clinical and laboratory findings

The bacterium Rickettsia rickettsii is the etiological agent of an acute, severe disease called Rocky Mountain spotted fever in the United States or Brazilian spotted fever (BSF) in Brazil. In addition to these two countries, the disease has also been reported to affect humans in Mexico, Costa Rica, Panama, Colombia and Argentina. Like humans, dogs are also susceptible to R. rickettsii infection. However, despite the wide distribution of R. rickettsii in the Western Hemisphere, reports of R. rickettsii-induced illness in dogs has been restricted to the United States. The present study evaluated the pathogenicity for dogs of a South American strain of R. rickettsii. Three groups of dogs were evaluated: group 1 (G1) was inoculated ip with R. rickettsii; group 2 (G2) was infested by R. rickettsii-infected ticks; and the control group (G3) was infested by uninfected ticks. During the study, no clinical abnormalities, Rickettsia DNA or R. rickettsii-reactive antibodies were detected in G3. In contrast, all G1 and G2 dogs developed signs of rickettsial infection, i.e., fever, lethargy, anorexia, ocular lesions, thrombocytopenia, anemia and detectable levels of Rickettsia DNA and R. rickettsii-reactive antibodies in their blood. Rickettsemia started 3-8 days after inoculation or tick infestation and lasted for 3-13 days. Our results indicate that a Brazilian strain of R. rickettsii is pathogenic for dogs, suggesting that canine clinical illness due to R. rickettsii has been unreported in Brazil and possibly in the other South American countries where BSF has been reported among humans.

A continuous strain-space model of viral evolution within a host

Viruses rapidly evolve, and HIV in particular is known to be one of the fastest evolving human viruses. It is now commonly accepted that viral evolution is the cause of the intriguing dynamics exhibited during HIV infections and the ultimate success of the virus in its struggle with the immune system. To study viral evolution, we use a simple mathematical model of the within-host dynamics of HIV which incorporates random mutations. In this model, we assume a continuous distribution of viral strains in a one-dimensional phenotype space where random mutations are modelled by di ffusion. Numerical simulations show that random mutations combined with competition result in evolution towards higher Darwinian fitness: a stable traveling wave of evolution, moving towards higher levels of fi tness, is formed in the phenoty space.

Time-based distribution of Staphylococcus saprophyticus pulsed field gel-electrophoresis clusters in community-acquired urinary tract infections

The epidemiology of urinary tract infections (UTI) by Staphylococcus saprophyticus has not been fully characterised and strain typing methods have not been validated for this agent. To evaluate whether epidemiological relationships exist between clusters of pulsed field gel-electrophoresis (PFGE) genotypes of S. saprophyticus from community-acquired UTI, a cross-sectional surveillance study was conducted in the city of Rio de Janeiro, Brazil. In total, 32 (16%) female patients attending two walk-in clinics were culture-positive for S. saprophyticus. Five PFGE clusters were defined and evaluated against epidemiological data. The PFGE clusters were grouped in time, suggesting the existence of community point sources of S. saprophyticus. From these point sources, S. saprophyticus strains may spread among individuals.

Retrospective distribution of Trypanosoma cruzi I genotypes in Colombia

Trypanosoma cruziis the aetiological agent of Chagas disease, which affects approximately eight million people in the Americas. This parasite exhibits genetic variability, with at least six discrete typing units broadly distributed in the American continent. T. cruziI (TcI) shows remarkable genetic diversity; a genotype linked to human infections and a domestic cycle of transmission have recently been identified, hence, this strain was named TcIDom. The aim of this work was to describe the spatiotemporal distribution of TcI subpopulations across humans, insect vectors and mammalian reservoirs in Colombia by means of molecular typing targeting the spliced leader intergenic region of mini-exon gene. We analysed 101 TcI isolates and observed a distribution of sylvatic TcI in 70% and TcIDom in 30%. In humans, the ratio was sylvatic TcI in 60% and TcIDom in 40%. In mammal reservoirs, the distribution corresponded to sylvatic TcI in 96% and TcIDom in 4%. Among insect vectors, sylvatic TcI was observed in 48% and TcIDom in 52%. In conclusion, the circulation of TcIDom is emerging in Colombia and this genotype is still adapting to the domestic cycle of transmission. The epidemiological and clinical implications of these findings are discussed herein.

Assessment of distribution and evolution of mechanical dyssynchrony in a porcine model of myocardial infarction by cardiovascular magnetic resonance.

BACKGROUND: We sought to investigate the relationship between infarct and dyssynchrony post- myocardial infarct (MI), in a porcine model. Mechanical dyssynchrony post-MI is associated with left ventricular (LV) remodeling and increased mortality. METHODS: Cine, gadolinium-contrast, and tagged cardiovascular magnetic resonance (CMR) were performed pre-MI, 9 ± 2 days (early post-MI), and 33 ± 10 days (late post-MI) post-MI in 6 pigs to characterize cardiac morphology, location and extent of MI, and regional mechanics. LV mechanics were assessed by circumferential strain (eC). Electro-anatomic mapping (EAM) was performed within 24 hrs of CMR and prior to sacrifice. RESULTS: Mean infarct size was 21 ± 4% of LV volume with evidence of post-MI remodeling. Global eC significantly decreased post MI (-27 ± 1.6% vs. -18 ± 2.5% (early) and -17 ± 2.7% (late), p < 0.0001) with no significant change in peri-MI and MI segments between early and late time-points. Time to peak strain (TTP) was significantly longer in MI, compared to normal and peri-MI segments, both early (440 ± 40 ms vs. 329 ± 40 ms and 332 ± 36 ms, respectively; p = 0.0002) and late post-MI (442 ± 63 ms vs. 321 ± 40 ms and 355 ± 61 ms, respectively; p = 0.012). The standard deviation of TTP in 16 segments (SD16) significantly increased post-MI: 28 ± 7 ms to 50 ± 10 ms (early, p = 0.012) to 54 ± 19 ms (late, p = 0.004), with no change between early and late post-MI time-points (p = 0.56). TTP was not related to reduction of segmental contractility. EAM revealed late electrical activation and greatly diminished conduction velocity in the infarct (5.7 ± 2.4 cm/s), when compared to peri-infarct (18.7 ± 10.3 cm/s) and remote myocardium (39 ± 20.5 cm/s). CONCLUSIONS: Mechanical dyssynchrony occurs early after MI and is the result of delayed electrical and mechanical activation in the infarct.

A single strain of Mycobacterium bovis bacillus Calmette-Guérin (BCG) grown in two different media evokes distinct humoral immune responses in mice

Two attenuated bacillus Calmette-Guérin (BCG) preparations derived from the same Moreau strain, Copenhagen but grown in Sauton medium containing starch and bacto-peptone (onco BCG, O-BCG), or asparagine (intradermal BCG, ID-BCG), exhibited indistinguishable DNA sequences and bacterial morphology. The number of viable bacilli recovered from spleen, liver and lungs was approximately the same in mice inoculated with the vaccines and was similarly reduced (over 90%) in mice previously immunized with either BCG vaccine. The humoral immune response evoked by the vaccines was, however, distinct. Spleen cell proliferation accompanying the growth of bacilli in tissue was significantly higher in mice inoculated with O-BCG. These cells proliferated in vitro upon challenge with the corresponding BCG extract. Previous cell treatment with mAb anti-CD4 T cells abolished this effect. Anti-BCG antibodies, as assayed either in serum by ELISA or by determining the number of antibody-producing spleen cells by the spot-ELISA method, were significantly higher in mice inoculated with ID-BCG. Anti-BCG antibodies were detected in all immunoglobulin classes, but they were more prevalent in IgG with the following distribution among its isotypes: IgG1>(IgG2a = IgG2b)>IgG3. When some well-characterized Mycobacterium tuberculosis antigens were used as substitutes for BCG extracts in ELISA, although antibodies against the 65-kDa and 96-kDa proteins were detected significantly, antibodies against the 71-kDa, 38-kDa proteins and lipoarabinomannan were only barely detected or even absent. These results indicate that BCG bacilli cultured in Sauton-asparagine medium permitted the multiplication of bacilli, tending to induce a stronger humoral immune response as compared with bacilli grown in Sauton-starch/bacto-peptone-enriched medium.

Distribution, extracellular virulence factors and antibiogram of motile aeromonads in fresh water ornamental fishes and immune response of Cyprinus carpio against Aeromonas hydrophila infection

The thesis deals with the prevalence and distribution of motile aeromonads in selected ornamental fishes. The presence of motile aeromonads in ornamental fishes and associated carriage water is well documented. Though aeromonads are a part of autochthonous flora of natural waters, disease outbreak occurs as a result of environmental stress on the cultured species and virulence of the pathogens. While ornamental aquaculture in many parts of the world is highly organized and practiced scientifically, it is highly unorganized in India. The culture ponds/tanks are often maintained in very poor manner and the fishes are subjected to high degree of stress during transportation from the production facility to retail vendors. The situation is no better at retail outlets, where fishes are maintained in crowded condition without proper aeration or food. All these could result in high prevalence of diseases caused by motile aeromonads. No systematic study has been carried out to understand the prevalence of motile aeromonads in ornamental fishes and carriage water . It also gives an account of the production of extracellular virulence factors and the antibiogram of the different species of motile aeromonads isolated. The growth characteristics and virulence potential of a representative strain of Aeromonas hydrophila is also studied. The nucleotide sequencing of the strain was carried out and sequences deposited in Genbank. Survival and immune response of Cyprinus carpio under different stress conditions and on probiotic treatment with Bacillus NL110, when challenged with A. hydrophila is also dealt within this thesis.

Strain longitudinal global para la detección de estenosis coronaria significativa en pacientes con infarto agudo del miocardio

Introducción: La evaluación de la función miocárdica global y regional juega una papel crítico en el diagnóstico y manejo de los pacientes con enfermedad coronaria con importantes implicaciones pronosticas, las nuevas técnicas ecocardiográficas como la evaluación del STRAIN han sido validadas como una herramienta objetiva, comprehensiva y precisa para evaluar dichos parámetros. Objetivo: Determinar la capacidad del strain global longitudinal para la detección de estenosis coronaria significativa, número de territorios comprometidos y territorio anatómico del vaso culpable; en pacientes sin antecedentes de enfermedad coronaria previa con infarto agudo del miocardio. Diseño: estudio de pruebas diagnósticas retrospectivo en el que se utilizó como gold estándar la angiografía coronaria, se seleccionaron 64 pacientes con ecocardiograma transtorácico previo a la angiografía coronaria. Resultados: Se demostró una exactitud intermedia del strain global longitudinal para detectar estenosis coronaria por análisis de curvas ROC, con un área bajo la curva de 0,78 p= 0,000 (IC 0,6; 1,0), Una sensibilidad de 96.5% (91.7%, 101.3%), especificidad 40.0% (9.6%, 70.4%) y una prevalencia real del enfermedad coronaria de 85.1% (76.5%, 93.6%) Conclusiones: La medición de la función global y regional por medio del strain global longitudinal identifica pacientes con infarto agudo del miocardio que tienen estenosis coronaria significativa, número de territorios afectados, y la distribución anatómica de los posibles vasos culpables, sin embargo hay que tener precaución en su uso que sólo se limite a escenarios en donde pueda ser interpretado adecuadamente. Palabras clave: strain global bidimensional, detección de estenosis coronaria significativa, infarto del miocardio.

Effect of high dose selenium enriched yeast diets on the distribution of total selenium and selenium species within lamb tissues

The objective of this study was to determine the distribution of total selenium (Se) and of the proportion of total Se comprised as the selenized amino acids selenomethionine (SeMet) and selenocysteine (SeCys) within the post mortem tissues of lambs that were fed high dose selenized enriched yeast (SY), derived from a specific strain of Saccharomyces cerevisae CNCM (Collection Nationale de Culture de Micro-organism) I-3060. Thirty two Texel X Suffolk lambs (6.87 ± 0.23 kg BW) were offered both reconstituted milk replacer and a pelleted diet, both of which had been either supplemented with high SY (6.30 ± 0.18 mg Se/kg DM) or unsupplemented (0.13 ± 0.01 mg Se/kg of DM), depending on treatment designation, for a continuous period of 91 d. At enrollment and 28, 56 and 91 d following enrollment lambs were blood sampled. At the completion of the treatment period, five lambs from each treatment group were euthanased and samples of heart, liver, kidney and skeletal muscle (Longissimus Dorsi and Psoas Major) were retained for Se analysis. The inclusion of high SY increased (P < 0.001) whole blood Se concentration, reaching a maximum mean value of 815.2 ± 19.1 ng Se/mL compared with 217.8 ± 9.1 ng Se/mL in control animals. Tissue total Se concentrations were significantly (P < 0.001) higher in SY supplemented animals than in controls irrespective of tissue type; values were 26, 16, 8 and 3 times higher in skeletal muscle, liver, heart and kidney tissue of HSY lambs when compared to controls. however, the distribution of total Se and the proportions of total Se comprised as either SeMet or SeCys differed between tissue types. Selenocysteine was the predominant selenized amino acid in glandular tissues, such the liver and kidney. irrespective of treatment, although absolute values were markedly higher in HSY lambs. Conversely selenomethionine was the predominat selenized amino acid in cardiac and skeletal muscle (Longissimus Dorsi, and Psoas Major) tissues in HSY animals, although the same trend was not apparent for control lambs in which SeCys was the predominant selenized amino acid. It was concluded that there were increases in both whole blood and tissue total Se concentrations as a result of dietary supplementation with high dose of SY. Furthermore, distribution of total Se and Se species differed between both treatment designation and tissue type.

Sequence analysis and distribution in Salmonella enterica serovars of IS3-like elements

The genome of Salmonella enterica serovar Enteritidis was shown to possess three IS3-like insertion elements, designated IS1230A, B and C, and each was cloned and their respective deoxynucleotide sequences determined. Mutations in elements IS1230A and B resulted in frameshifts in the open reading frames that encoded a putative transposase to be inactive. IS1230C was truncated at nucleotide 774 relative to IS1230B and therefore did not possess the 3' terminal inverted repeat. The three IS1230 derivatives were closely related to each other based on nucleotide sequence similarity. IS1230A was located adjacent to the sef operon encoding SEF14 fimbriae located at minute 97 of the genome of S. Enteritidis. IS1230B was located adjacent to the umuDC operon at minute 42.5 on the genome, itself located near to one terminus of an 815-kb genome inversion of S. Enteritidis relative to S. Typhimurium. IS1230C was located next to attB, the bacteriophage P22 attachment site, and proB, encoding gamma-glutamyl phosphate reductase. A truncated 3' remnant of IS1230, designated IS1230T, was identified in a clinical isolate of S. Typhimurium DT193 strain 2391. This element was located next to attB adjacent to which were bacteriophage P22-like sequences. Southern hybridisation of total genomic DNA from eighteen phage types of S. Enteritidis and eighteen definitive types of S. Typhimurium showed similar, if not identical, restriction fragment profiles in the respective serovars when probed with IS1230A.