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1.
Immunogenetics ; 75(2): 81-89, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36229691

RESUMO

Merkel cell carcinoma (MCC) is a rare aggressive neuroendocrine cutaneous carcinoma with a high mortality rate. The MCC etiology is not fully understood. Merkel cell-associated polyomavirus (MCPyV) was found in MCC patients, indicating a risk factor for the tumor. Caucasian, elderly, and immunocompromised individuals are more likely to develop this tumor. HLA-G consists of a non-classical class I (Ib) HLA molecule with an immunoregulatory function and was associated with tumor escape in different types of tumors, nonetheless, never been studied in MCC. The purpose of this study was to evaluate the HLA-G expression and also to detect the MCPyV in MCC patients and correlate it with the clinical course of the disease. Forty-five MCC patients were included in a retrospective study. Formalin-fixed paraffin-embedded cutaneous skin biopsies were used by immunohistochemistry and RT-PCR to verify the HLA-G expression and MCPyV infection. HLA-G expression was found in 7 (15.6%), while the presence of MCPyV was detected in 28 (62.2%) of the studied patients. No significant association was found between HLA-G expression and MCPyV infection (p = 0.250). The presence of MCPyV was associated with areas of low sunlight exposure (p = 0.042) and the HLA-G expression with progression to death (p = 0.038). HLA-G expression was detected in MCC patients, as well as the MCPyV presence was confirmed. These markers could represent factors with a possible impact on patient survival; however, further studies with a greater number of patients are needed, to better elucidate the possible role in disease progression.


Assuntos
Carcinoma de Célula de Merkel , Poliomavírus das Células de Merkel , Infecções por Polyomavirus , Neoplasias Cutâneas , Humanos , Idoso , Carcinoma de Célula de Merkel/genética , Carcinoma de Célula de Merkel/patologia , Poliomavírus das Células de Merkel/genética , Antígenos HLA-G , Neoplasias Cutâneas/genética , Estudos Retrospectivos , Infecções por Polyomavirus/complicações , Infecções por Polyomavirus/genética
2.
Arch Orthop Trauma Surg ; 143(10): 6117-6122, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37219598

RESUMO

PURPOSE: Surrogate outcomes are clinical endpoints that are used as substitutes for direct measures of how a patient feels, functions, or survives. The present study aims to analyze the impact of surrogate outcomes on the results of randomized controlled trials on shoulder rotator cuff tears disorders. METHODS: Randomized controlled trials (RCTs) related to rotator cuff tear conditions published up until 2021 were retrieved from the PubMed and ACCESSSS databases. The primary outcome of the article was considered a surrogate outcome when the authors used radiological, physiologic, or functional variables. The result of the article was considered positive when results supported the intervention based on the trial's primary outcome. We recorded the sample size, the mean follow-up, and the type of funding. Statistical significance was set at p < 0.05. RESULTS: A total of 112 papers were included in the analysis. The mean sample size was 87.6 patients; mean follow-up period was 25.97 months. Thirty-six out of 112 RCTs used a surrogate outcome as a primary endpoint. More than half of papers using surrogate outcomes reported a positive finding (20 out of 36), while 10 out of 71 RCTs using patient-centered outcomes favored the intervention (14.08%, p < 0.001) [RR = 3.94 (95% CI 2.07-7.51)]. The mean sample size was smaller in trials using surrogate endpoints (75.11 vs 92.35 patients, respectively, p = 0.049), while the follow-up was shorter (14.12 m vs. 31.9 m, p < 0.001). Approximately 25% of the papers that reported surrogate endpoints (22.58%) were industry-funded projects. CONCLUSIONS: The substitution of surrogate endpoints for patient-important outcomes in shoulder rotator cuff trials quadruplicates the chances of obtaining a favorable result that favors the analyzed intervention.


Assuntos
Lesões do Manguito Rotador , Ombro , Humanos , Lesões do Manguito Rotador/cirurgia , Resultado do Tratamento , Artroscopia/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
J Fish Biol ; 92(6): 1985-1999, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29660124

RESUMO

Between 2003 and 2005, vertebrae of 151 Xingu River Potamotrygon leopoldi (Potamotrygonidae) (75 males and 76 females) were analysed to derive a growth curve for this species. The disc width (WD ) was significantly different between sexes, with females measuring 149-700 mm WD and males 109-500 mm WD . The average percentage error for vertebrae readings of the whole sample was 2·7%. The marginal increment ratio (RMI ) showed an increasing trend with the highest value in November, decreasing from December on. The majority of vertebrae displaying RMI zero, occurred in September, but the annual periodicity of ring deposition throughout the year was not conclusive. Tetracycline (TCN) injected specimens were held in captivity for 13 months and displayed a fluorescent mark in vertebrae confirming a yearly periodicity of band pair formation with the translucent ring deposited in September-October. The Akaike information criterion (AIC) showed that, among the seven models considered, the best fit was obtained for the von Bertalanffy modified with W0 (where W0 = WD at birth) for both sexes. Growth parameters for females were: W0 = 149 mm; W∞ = 763·06 mm; k = 0·12 year- 1 , whereas for males: W0 = 109 mm; W∞ = 536·4 and k = 0·22 year-1 . Maximal ages were 7·2 years in males and 14·3 years in females. The species shows sexual dimorphism expressed in the growth pattern, size at maturity, longevity and asymptotic sizes. Concern for sustainability is raised due to the construction of the Belo Monte Hydroelectric Power Plant (2015 and 2016) in the State of Pará causing changes to the habitat of this species, which is endemic to the Xingu River and two of its tributaries.


Assuntos
Determinação da Idade pelo Esqueleto/métodos , Rajidae/crescimento & desenvolvimento , Distribuição por Idade , Animais , Brasil , Ecossistema , Feminino , Corantes Fluorescentes , Masculino , Periodicidade , Rios , Tetraciclina
4.
Arch Orthop Trauma Surg ; 138(11): 1533-1539, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30062459

RESUMO

PURPOSE: We aimed to biomechanically evaluate the effect of the supraspinatus tendon on tuberosity stability using two different reverse shoulder arthroplasty (RSA) models for complex proximal humeral fractures (PHFs). METHODS: Four-part proximal humeral fractures were simulated in 20 cadaveric shoulders. Two different RSA designs were implemented: a glenosphere-medialized model and a glenosphere-lateralized model. Tuberosities were reconstructed, and displacement of bony fragments was measured (mm) by placing three sensors: in the humeral diaphysis (D), in the greater tuberosity (GT), and in the lesser tuberosity (LT). Axial forces were induced and measured in Newton (N). The test was performed twice in each specimen, with and without the supraspinatus tendon. The regression line (RL) was measured in mm/N. RESULTS: In the medialized model, the GT-D displacement was greater in the supraspinatus preserving model than that in the tendon excision model (p < 0.001), as well as for the LT-D displacement (p < 0.001). In the lateralized model, GT-D displacement and GT-LT distance were greater in the preserving model than that in the excision model (p < 0.001, p = 0.04). CONCLUSION: The supraspinatus tendon resection leads to a more biomechanically stable tuberosity construct when performing RSA for PHFs, while the rest of the rotator cuff tendons (infraspinatus and teres minor) are retained in the greater tuberosity. LEVEL OF EVIDENCE: Basic science study. Cadaveric study.


Assuntos
Artroplastia do Ombro/métodos , Manguito Rotador/cirurgia , Fraturas do Ombro/cirurgia , Prótese de Ombro/efeitos adversos , Tendões/cirurgia , Idoso , Fenômenos Biomecânicos , Cadáver , Humanos , Úmero/cirurgia , Pessoa de Meia-Idade , Implantação de Prótese , Articulação do Ombro/cirurgia
5.
J Fish Biol ; 89(1): 977-89, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27245983

RESUMO

Age and growth of the dolphinfish Coryphaena hippurus caught off north-eastern Brazil were studied by counting growth increments on scales and otoliths. A sample (n = 2338) measuring 7·7-195 cm fork length (LF ) was collected from September 2001 to February 2003. The scales (n = 69) removed from six different regions of the body were examined and those from the caudal region exhibited greater morphological regularity, symmetry and a smaller rate of regeneration. The regression between caudal scale radius (RS ) and LF displayed was linear (LF = 28·334 RS + 9·186; r(2) = 0·754). Otolith micro-increments were counted assuming daily periodicity. Ages estimated from otoliths ranged from 64 to 659 days. The von Bertalanffy growth model was fitted based on the otolith readings generating L∞ = 194·1 cm LF , k = 0·912 year(-1) and t0 = 0·081 years. Species longevity was estimated to be c. 4 years. Ninety-eight per cent of the overall sample was adult specimens well above the age of first maturity in the study area. The large variability between scale length and LF and the failure to ascertain increment deposition periodicity suggest that scales are not appropriate for ageing C. hippurus and analysis of otolith micro-increments is deemed the best structure for ageing this species in the study area.


Assuntos
Envelhecimento , Tamanho Corporal , Perciformes/crescimento & desenvolvimento , Animais , Brasil , Longevidade , Perciformes/anatomia & histologia
6.
J Fish Biol ; 89(1): 371-85, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26179442

RESUMO

Age and growth were analysed on the basis of 372 vertebrae from specimens of the crocodile shark Pseudocarcharias kamoharai (66·0-122·0 cm, total length, LT ) collected in the south-western Atlantic Ocean. Centrum edge analysis suggested the first four months of the year as the period of band completion, leading to acceptance of free-living bands as annual. A pre-birth ring is formed in embryos >31·0 cm LT , whereas the birthmark is deposited in newborns of 46·1 ± 1·1 cm LT (mean ± s.d.). Growth was parameterized using seven models and the AIC was used for selection of the most plausible model. The von Bertalanffy growth model received the greatest support from the data, providing the following growth parameters for combined sexes: L∞ = 129·2 cm, k = 0·137 year(-1) and t0 = -3·9 years. No significant differences were detected in growth by sex, but significant differences in age composition by sex were found in the sample. Overall age ranged from 2 to >13 years in females and from 1 to 8 years in males. Males achieved first maturity at 3·1 years and females at 5·1 years, with pregnancy appearing at 4·8 years. Similar to other lamnoid species, P. kamoharai is relatively fast growing.


Assuntos
Determinação da Idade pelo Esqueleto , Tubarões/crescimento & desenvolvimento , Animais , Oceano Atlântico , Tamanho Corporal , Feminino , Masculino , Modelos Biológicos , Gravidez , Coluna Vertebral/crescimento & desenvolvimento
7.
Eur J Vasc Endovasc Surg ; 48(4): 452-8, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25150439

RESUMO

OBJECTIVES: To get to know the influence of the four domains of the Chronic Lower Limb Venous Insufficiency Questionnaire (CIVIQ) on the quality of life (QoL) of patients with primary superficial venous incompetence, and their behaviour in relation to age, gender, occupation, body mass index (BMI), and also with respect to the clinical and anatomical classes of the CEAP. MATERIAL AND METHODS: The sample was composed of 468 patients with primary superficial venous reflux (135 male and 333 female) who answered 100% of the questions in the Short Form-12 (SF12) and CIVIQ questionnaires. After a clinical and duplex examination, the patients were categorized as C0-6, Ep, As, Ap or As,p and Pr according to the CEAP classification. The relationships between CIVIQ domains and gender, age, occupation, BMI, and the clinical and anatomical classes of the CEAP classification were analyzed. RESULTS: Men reported better QoL than women (33.2 vs. 46.3) and this was also true for each of the CIVIQ's domains (p < .00). Pain (50.6) and physical restriction (45.3) were the dimensions with a greater influence on QoL, whereas social (41.7) and psychological (38.1) dimensions had a lesser influence. Patients aged between 45 and 64, household activities, and patients with C2-3 clinical classes were the patient groups with the worst scores in all the CIVIQ dimensions and those where significant differences were found. The BMI and anatomical distribution of the reflux had no influence on the QoL. CONCLUSIONS: Pain and physical restriction were the CIVIQ domains with greater influence on the QoL of patients with primary superficial venous reflux. Age increase (up to 64 years), female gender, household activities, and C2-3 CEAP clinical class were the main factors associated with the worst QoL perception.


Assuntos
Qualidade de Vida , Inquéritos e Questionários , Insuficiência Venosa/psicologia , Adolescente , Adulto , Distribuição por Idade , Idoso , Estudos Transversais , Feminino , Humanos , Extremidade Inferior/irrigação sanguínea , Masculino , Pessoa de Meia-Idade , Morbidade , Distribuição por Sexo , Fatores Sexuais , Espanha/epidemiologia , Ultrassonografia Doppler Dupla , Insuficiência Venosa/diagnóstico , Insuficiência Venosa/epidemiologia , Adulto Jovem
8.
Genet Mol Res ; 13(3): 6683-700, 2014 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-25177949

RESUMO

The aim of this study was to estimate the genetic parameters and predict the genotypic values of root quality traits in cassava (Manihot esculenta Crantz) using restricted maximum likelihood (REML) and best linear unbiased prediction (BLUP). A total of 471 cassava accessions were evaluated over two years of cultivation. The evaluated traits included amylose content (AML), root dry matter (DMC), cyanogenic compounds (CyC), and starch yield (StYi). Estimates of the individual broad-sense heritability of AML were low (hg(2) = 0.07 ± 0.02), medium for StYi and DMC, and high for CyC. The heritability of AML was substantially improved based on mean of accessions (hm(2) = 0.28), indicating that some strategies such as increasing the number of repetitions can be used to increase the selective efficiency. In general, the observed genotypic values were very close to the predicted average of the improved population, most likely due to the high accuracy (>0.90), especially for DMC, CyC, and StYi. Gains via selection of the 30 best genotypes for each trait were 4.8 and 3.2% for an increase and decrease for AML, respectively, an increase of 10.75 and 74.62% for DMC for StYi, respectively, and a decrease of 89.60% for CyC in relation to the overall mean of the genotypic values. Genotypic correlations between the quality traits of the cassava roots collected were generally favorable, although they were low in magnitude. The REML/BLUP method was adequate for estimating genetic parameters and predicting the genotypic values, making it useful for cassava breeding.


Assuntos
Algoritmos , Técnicas de Genotipagem/métodos , Manihot/genética , Modelos Genéticos , Raízes de Plantas/genética , Amilose/metabolismo , Biomassa , Genótipo , Glicosídeos/metabolismo , Padrões de Herança/genética , Manihot/classificação , Manihot/metabolismo , Fenótipo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Característica Quantitativa Herdável , Seleção Genética , Especificidade da Espécie , Amido/metabolismo
10.
J Med Primatol ; 42(6): 287-92, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23879249

RESUMO

BACKGROUND: This study aimed to establish reference values for selected ophthalmic diagnostic tests in healthy neotropical primates from Salvador, Brazil. METHODS: A total of 73 intact adults, including Callithrix jacchus (n = 31), Callithrix penicillata (n = 8), Cebus sp. (n = 22), and Cebus xanthosternos (n = 9) were used to evaluate the normal conjunctival bacterial flora. Cebus xanthosternos (n = 12) were used to evaluate tear production with Schirmer's tear test (STT), intraocular pressure (IOP), and conjunctival cytology. RESULTS: For all animals evaluated, Gram-positive bacteria were predominant. Results of the diagnostic tests in Cebus xanthosternos were as follows: STT: 14.92 ± 5.46 mm/minutes, IOP: 19.62 ± 4.57 mmHg, and conjunctival cytology revealed intermediate squamous epithelial cells in great quantities. CONCLUSIONS: These ophthalmic reference values will be particularly useful to diagnose discrete or unusual pathological changes in the neotropical primates eye.


Assuntos
Callithrix/microbiologia , Cebus/microbiologia , Túnica Conjuntiva/microbiologia , Animais , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/veterinária , Brasil , Células Cultivadas , Túnica Conjuntiva/citologia , Túnica Conjuntiva/patologia , Feminino , Masculino , Valores de Referência , Lágrimas/microbiologia , Tonometria Ocular/normas
11.
J Eur Acad Dermatol Venereol ; 27(2): e166-70, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22458812

RESUMO

BACKGROUND: Fissured tongue (FT) is a clinical condition manifested by numerous little furrows on the tongue's surface. Previously, the authors observed an association with HLA-C×06 in psoriasis (PS) and benign migratory glossitis (BMG); however, HLA-C was not surveyed in FT. OBJECTIVE: This study investigated the association between HLA alleles and FT. METHODS: Thirty-three FT bearers were studied, after evaluation of criteria for inclusion. These patients did not present PS, BMG or any other conditions associated with FT. The control group (CG) was composed of 561 individuals with HLA-A, 560 individuals with HLA-B, 168 individuals with HLA-C, 564 individuals with HLA-DRB1 and 390 individuals with HLA-DQB1. Samples from these individuals were processed to extract DNA. The HLA classes I and II were determined using the reverse line blot technique. The frequencies of HLA antigens found in patients were compared with the CG using Fisher's exact test. RESULTS: The comparison of the frequencies of HLA antigens found in the patient groups and in CG revealed no association with any of the alleles studied, except for HLA-A*01, which exhibited a decreased frequency in patient groups. HLA-C*06 was detected in 7.57% of FT patients and 10.42% of the CG (not significant). CONCLUSION: The lack of association of FT with HLA-C*06 reinforces the proposal that this disease does not have a common genetic factor in the triad of BMG, FT and PS.


Assuntos
Alelos , Antígenos HLA/genética , Língua Fissurada/genética , Brasil , Estudos de Casos e Controles , Humanos , Língua Fissurada/imunologia
13.
Int Endod J ; 46(8): 738-46, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23551247

RESUMO

AIM: To analyse the effect of calcium hydroxide paste, endodontic irrigants and time of application on the bond strength of fibre posts to root canal dentine. METHODOLOGY: Seventy bovine incisors were divided into 7 groups according to removal of calcium hydroxide and distilled water (CHW) (immediate - I; 21 days - 21 days; 6 months - 6 months) and endodontic irrigant (1% sodium hypochlorite - SH; 1% sodium hypochlorite + 17% EDTA - SHE). Fibre posts were cemented (RelyX U100), after which the roots were serially sectioned and submitted to a micro-push-out test. Data were analysed using two-way anova followed by the Tukey's and the Dunnett's tests (α = 0.05). RESULTS: The CHW groups were not significantly different from the control group in 13 of the 18 associated factors (P > 0.05). There were significant reductions in bond strength in the cervical (P = 0.0216) and middle (P = 0.0017) thirds of the root at 6 months in groups irrigated with SH. Irrigation with SHE reduced the bond strength significantly in the middle (P = 0.0488) and apical (P = 0.0252) thirds of the roots in the immediate groups and in the middle third (P = 0.0287) in the 21-day group. Bond strength was greater in the cervical than in the apical thirds of all immediate and 21-day groups (P < 0.05). CONCLUSIONS: Bond strength of groups that received CH paste was similar to that found in the control group in 13 of the 18 associated factors. EDTA and SH reduced bond strength in specimens in the immediate (middle and apical thirds) and 21-day (middle third) groups. There was a significant reduction in bond strength in the groups irrigated with SH and tested at 6 months (cervical and middle thirds). There was a predominance of adhesive failures between resin cement and dentine in all groups.


Assuntos
Hidróxido de Cálcio/química , Colagem Dentária , Cavidade Pulpar/ultraestrutura , Dentina/ultraestrutura , Técnica para Retentor Intrarradicular/instrumentação , Irrigantes do Canal Radicular/química , Adesividade , Animais , Bovinos , Cimentação/métodos , Análise do Estresse Dentário/instrumentação , Ácido Edético/química , Cura Luminosa de Adesivos Dentários/métodos , Distribuição Aleatória , Cimentos de Resina/química , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Hipoclorito de Sódio/química , Estresse Mecânico , Propriedades de Superfície , Temperatura , Fatores de Tempo , Ápice Dentário/ultraestrutura , Colo do Dente/ultraestrutura , Água/química
14.
Environ Monit Assess ; 185(10): 8125-33, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23494195

RESUMO

In this report, the development of an online, noninvasive, measurement method of the biofilm thickness in a liquid phase is presented. The method is based in the analysis of the ultrasound wave pulse-echo behavior in a liquid phase reproducing the real reactor conditions. It does not imply the removal of the biomass from the support or any kind of intervention in the support (pipes) to detect and perform the measurements (non-invasiveness). The developed method allows for its sensor to be easily and quickly mounted and unmounted in any location along a pipe or reactor wall. Finally, this method is an important innovation because it allows the thickness measurement of a biofilm, in liquid phase conditions that can be used in monitoring programs, to help in scheduling cleaning actions to remove the unwanted biofilm, in several application areas, namely in potable water supply pipes.


Assuntos
Biofilmes/crescimento & desenvolvimento , Drenagem Sanitária , Monitoramento Ambiental/métodos , Abastecimento de Água , Ultrassom , Microbiologia da Água
15.
Environ Monit Assess ; 185(12): 10085-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23797637

RESUMO

Biofilms are present in several areas and are studied in microbiology, medical sciences, biology and, of course, sanitary engineering. Biofilms are used for the treatment of municipal wastewater, and their application was even before the invention of the activated sludge process. The main objective of this work was to develop a simple, fast and low-cost technique to evaluate the nature of the first decay in the concentration of an organic compound in the presence of a solid material. Though simple, the technique developed has allowed the clarification of whether the initial concentration decay is due to adsorption to the support material or a result of biodegradation. The results show that, with two different support materials, adsorption does not take place, and the biodegradation processes are responsible for the first decay in the organic concentration. The technique used offers a fast and low-cost way of studying the existence of adsorption. Two feed concentration solutions and two different support materials were used.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/metabolismo , Adsorção , Biodegradação Ambiental , Cinética , Eliminação de Resíduos Líquidos/economia , Águas Residuárias/microbiologia
16.
Public Health Pract (Oxf) ; 6: 100419, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37608848

RESUMO

Objective: Assess the perceived protection afforded by a range of COVID-19 vaccines in immune-mediated inflammatory diseases patients previously vaccinated against SARS-CoV-2. Study design: Survey. Methods: On-line cross-sectional survey aimed at evaluating the perceived protection (and its determinants) afforded by a range of COVID-19 vaccines among immune-mediated inflammatory diseases previously vaccinated for COVID-19. Results: Out of 493 eligible respondents who lived in Brazil, 397 (80.5%) were confident that their primary vaccination series would protect them against severe COVID-19. In multivariate analysis, only overlapping immune-mediated inflammatory diseases remained (negatively) associated with the perception of protection. Conclusions: No influence was found between COVID-19 vaccine types and the perception of protection after initial vaccinations.

17.
Int Endod J ; 45(9): 840-7, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22486728

RESUMO

AIM: To investigate ex vivo the influence of the post system on fracture resistance and failure mode of root filled incisor, canine, premolar and molar teeth. METHODOLOGY: Eighty human teeth were divided into eight groups (n = 10) resulting from the interaction between the two study factors: post system (glass fibre post; cast Ni-Cr alloy post and core) and type of tooth (maxillary incisors, maxillary canines, maxillary premolars and mandibular molars). All roots were prepared with a 2-mm ferrule and restored with metal crown. Fracture resistance (N) was assessed in a mechanical testing device, and the data were analysed by two-way anova (4 × 2) followed by Tukey's test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. Failure mode data were analysed by two-factor anova and Student-Newman-Keuls (SNK) tests (α = 0.05). Correlation between fracture resistance and failure mode was analysed by linear regression. RESULTS: Glass fibre and cast posts and cores had similar fracture resistance, regardless of the type of tooth. Canines and molars had significantly higher fracture resistance (P < 0.001) than premolars. Incisors teeth had significantly lower fracture resistance (P < 0.001) than premolars. The fracture mode for incisors, premolars and molars was more amenable to restoration when the teeth were restored with glass fibre posts. Fracture resistance had no correlation with fracture mode, regardless of the post system and type of tooth analysed. CONCLUSIONS: Post system had no significant effect on fracture resistance, regardless of the type of tooth. The mode of fracture was more restorable with glass fibre posts.


Assuntos
Técnica para Retentor Intrarradicular , Fraturas dos Dentes/fisiopatologia , Dente não Vital/fisiopatologia , Condicionamento Ácido do Dente/métodos , Dente Pré-Molar/fisiopatologia , Fenômenos Biomecânicos , Ligas de Cromo/química , Resinas Compostas/química , Coroas , Dente Canino/fisiopatologia , Cimentos Dentários/química , Materiais Dentários/química , Análise do Estresse Dentário/instrumentação , Vidro/química , Humanos , Incisivo/fisiopatologia , Mandíbula , Teste de Materiais , Maxila , Dente Molar/fisiopatologia , Ácidos Fosfóricos/química , Preparo de Canal Radicular/métodos , Estresse Mecânico
18.
J Fish Biol ; 81(6): 2080-5, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23130703

RESUMO

Two tagged-and-recaptured tiger sharks Galeocerdo cuvier, measuring 172 and 304 cm total length (L(T) ) and at age 0.75 and 3.50 years, exhibited unmatched growth rates of 118.4 and 55.5 cm year(-1), respectively. The larger fish was nearly mature, indicating that G. cuvier off Brazil could mature considerably earlier than conspecifics from other regions.


Assuntos
Tubarões/crescimento & desenvolvimento , Animais , Oceano Atlântico , Brasil , Feminino , Masculino
19.
Int Endod J ; 44(5): 386-94, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21314691

RESUMO

AIM: To investigate ex vivo the influence of post system and amount of remaining coronal tooth tissue on the fracture resistance, fracture mode and strain of root filled molar teeth. METHODOLOGY: Seventy mandibular human molar teeth were divided into seven groups (n = 10), one control (sound teeth) and six experimental groups resulting from the interaction between the two study factors: post system (Pa, post absence; Gfp, glass fibre post; Cmp, cast Ni-Cr alloy post and core) and amount of remaining coronal tooth tissue (Fe, 2 mm of ferrule; NFe, no ferrule). Teeth in the experimental groups were restored with metal crowns. For the strain gauge test, two strain gauges per sample were attached on the buccal and proximal root surfaces, and the samples of each group (n = 5) were submitted to a load of 0-100N. Fracture resistance (N) was assessed in a mechanical testing device (n = 10). Strain gauge and fracture resistance data were analysed by two-way anova (3 × 2) followed by the Tukey's HSD and Duncan's test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. RESULTS: The absence of ferrule was associated with lower fracture resistance regardless of the post system. Groups restored with glass fibre post and cast Ni-Cr alloy post and core had similar fracture resistance and higher values than groups without posts, regardless of the remaining coronal tooth tissue. Teeth with no ferrule and cast Ni-Cr alloy post and core resulted in catastrophic fractures and those with no ferrule and glass fibre post or no ferrule and post absence resulted in restorable failures. Buccal strain was higher in sound teeth and lower in teeth without posts. Glass fibre post insertion decreased the buccal strain compared to the teeth with ferrule and absence of post. CONCLUSIONS: Two millimetre of ferrule had a significant influence on cusp strain, fracture resistance and failure mode. The glass fibre post was as effective as the cast Ni-Cr alloy post and core in the restoration of root filled molars regardless of the remaining tooth tissue. Absence of a post decreased the fracture resistance and increased the cusp strain.


Assuntos
Planejamento de Prótese Dentária , Falha de Restauração Dentária , Técnica para Retentor Intrarradicular/instrumentação , Coroa do Dente/patologia , Fraturas dos Dentes/prevenção & controle , Fenômenos Biomecânicos , Ligas Dentárias , Análise do Estresse Dentário , Vidro , Humanos , Mandíbula , Dente Molar , Tratamento do Canal Radicular/instrumentação , Tratamento do Canal Radicular/métodos , Estresse Mecânico
20.
Int Endod J ; 44(11): 1047-54, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21740445

RESUMO

AIM: To investigate ex vivo the influence of gamma irradiation therapy and restorative material on fracture resistance, fracture mode and strain of root filled human premolars. METHODOLOGY: Sixty extracted human maxillary premolar teeth were randomly divided into six groups (n = 10) determined by two study factors: (i) restorative materials: sound teeth, root filled teeth restored with composite resin, root filled teeth restored with amalgam; (ii) gamma irradiation: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and nonirradiated. For the strain gauge test, two strain gauges per sample were attached on the buccal and palatal cusp surfaces (n = 5). Strain values were recorded during loading of 0-150 N. Fracture resistance (N) was assessed in a mechanical testing machine (n = 10). Strain gauge for each cusp and fracture resistance data were analysed by two-way anova (3 × 2) followed by the Tukey's honestly significant difference test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. RESULTS: Gamma radiation therapy significantly reduced the fracture resistance of intact teeth. The strain was higher for teeth restored with amalgam than for those restored with composite resin. The teeth restored with composite resin had similar strain values to sound teeth. Nonirradiated teeth had more restorable failures than irradiated teeth. CONCLUSIONS: Gamma irradiation significantly reduced fracture resistance and increased cusp strain. The use of composite resin resulted in better biomechanical behaviour than amalgam for restoring root filled teeth whether or not they were submitted to radiotherapy.


Assuntos
Materiais Dentários/efeitos da radiação , Raios gama/efeitos adversos , Radioterapia/efeitos adversos , Tratamento do Canal Radicular , Fraturas dos Dentes/etiologia , Dente não Vital/complicações , Análise de Variância , Dente Pré-Molar/patologia , Dente Pré-Molar/efeitos da radiação , Fenômenos Biomecânicos , Estudos de Casos e Controles , Resinas Compostas/efeitos da radiação , Amálgama Dentário/efeitos da radiação , Falha de Restauração Dentária , Restauração Dentária Permanente , Análise do Estresse Dentário , Humanos , Maxila , Dosagem Radioterapêutica , Valores de Referência , Estatísticas não Paramétricas , Fraturas dos Dentes/patologia
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