Calvarial Model of Bone Augmentation in Rabbit for Assessment of Bone Growth and Neovascularization in Bone Substitution Materials.

The basic principle of the rabbit calvarial model is to grow new bone tissue vertically on top of the cortical part of the skull. This model allows assessment of bone substitution materials for oral and craniofacial bone regeneration in terms of bone growth and neovascularization support. Once animals are anesthetized and ventilated (endotracheal intubation), four cylinders made of polyether ether ketone (PEEK) are screwed onto the skull, on both sides of the median and coronal sutures. Five intramedullary holes are drilled within the bone area delimited by each cylinder, allowing influx of bone marrow cells. The material samples are placed into the cylinders which are then closed. Finally, the surgical site is sutured, and animals are awaken. Bone growth may be assessed on live animals by using microtomography. Once animals are euthanized, bone growth and neovascularization may be evaluated by using microtomography, immune-histology and immunofluorescence. As the evaluation of a material requires maximum standardization and calibration, the calvarial model appears ideal. Access is very easy, calibration and standardization are facilitated by the use of defined cylinders and four samples may be assessed simultaneously. Furthermore, live tomography may be used and ultimately a large decrease in animals to be euthanized may be anticipated.

An evaluation of new designs in implant-abutment connections: a finite element method assessment.

PURPOSE: This research sought first to evaluate the differences in the finite element method (FEM) analysis of 4 different implant surfaces, including internal and external connections of the same manufacturer with additional modifications. METHODS: In this study, 4 dental implants from the same manufacturer were compared. A connection system was modified with a collar to improve its stability. A nonlinear dynamic analysis by FEM was used to calculate the transient response of the dental implant systems. RESULTS: The results of FEM analysis indicated that the implant-modified configuration is more efficient in loading support when compared with the others. CONCLUSION: In the present research, 4 different types of connections were evaluated: a modified internal hex connection with a collar (to increase stability), an internal hex connection, a standard connection without hex, and an external connection. These data demonstrated that the internal hex connection with the modification of the manufacturer's original is much more resistant to loosening and/or distortion than the traditional hex.

Fatores de risco para infecção pelo HIV em pacientes com o vírus da hepatite C / Risk factors for HIV infection among patients infected with hepatitis C virus

OBJETIVO: Os vírus da imunodeficiência humana e o vírus da hepatite C apresentam fatores de transmissão em comum. Atualmente, há alta freqüência da co-infecção, principalmente em indivíduos usuários de drogas injetáveis e com história de transfusões. O objetivo do estudo foi avaliar os fatores de risco para infecção pelo HIV em pacientes infectados pelo vírus da hepatite C. MÉTODOS: Trata-se de estudo epidemiológico do tipo caso-controle, realizado com 118 pacientes (casos) infectados pelos vírus HIV e vírus da hepatite C e 233 pacientes (controles) infectados somente pelo vírus da hepatite C. Entre janeiro de 1999 a novembro de 2001, os pacientes foram submetidos a questionário sobre características sociodemográficas, profissionais, e principais fatores de risco para infecção pelos vírus. Após descritas e comparadas, as variáveis foram submetidas à análise univariada, e em seguida à análise de regressão logística para variáveis selecionadas pelo teste da razão da máxima verossimilhança. RESULTADOS: A co-infecção está associada ao sexo feminino (OR=2,89; IC 95 por cento: 1,16-7,08), aos estados civis separado/viúvo (OR=3,91; IC 95 por cento: 1,34-11,35), ao uso pregresso ou atual de drogas ilícitas (OR=3,96; IC 95 por cento: 1,55-0,13) e ao hábito de compartilhar canudos ou seringas (OR=10,28; IC 95 por cento: 4,00-6,42). CONCLUSÕES: Em pacientes infectados pelo vírus da hepatite C, o sexo feminino é fator de risco para a infecção pelo HIV quando ajustado à variável compartilhar canudos ou seringas. Os estados civis separado/viúvo, uso de drogas ilícitas e hábito de compartilhar canudos ou seringas são, também, fatores associados ao risco para esta co-infecção.

Clinical laboratory assessment of hepatitis C and HIV coinfected patients according to the antiretroviral therapy received.

During the year of 2001, a retrospective, descriptive study in order to determine the influence of the antiretroviral therapy received by 111 HIV-HCV coinfected patients who had undergone at least one liver biopsy was conducted, 74 of them were treated with a protease inhibitor regimen (WPI), and 37 with a non-protease inhibitor regimen (NPI). The main characteristics found were: a young patient population (mean age 41 years old in both groups), composed in most part of male individuals (74.3% WPI and 51.4% NPI) with previous risk factors for both infections (WPI 93.2% and NPI 89.2%). The most significant findings included AIDS-defining disease (WPI 18.9% and NPI 13.5% of the cases), elevated hepatic enzyme levels (WPI: SGOT 52.1 and NPI 53.2), absence of liver disease-related symptoms (16.2% for both groups), average CD4 count > 350 for both groups (WPI 362.2 and NPI 378.1), predominantly low-grade fibrosis in both populations (0-2 in 63.6% of WPI patients and in 80% of NPI patients), with necro-inflammatory activity ranging from 5-7 in 51.3% and 42.9% of WPI patients and NPI patients, respectively. It is suggested a sequential biopsy to better evaluate the evolution of the hepatic disease, according to the HAART regimen received.

Clinical laboratory assessment of hepatitis C and HIV coinfected patients according to the antiretroviral therapy received

Durante o ano de 2001, um estudo retrospectivo e descritivo foi efetuado a fim de determinar a influência da terapia antirretroviral recebida por 111 pacientes co-infectados HIV-HCV que tinham se submetido ao menos a uma biopsia hepática. Destes, 74 foram tratados com um regime contendo inibidor da protease (WPI) e 37 com um regime do não contendo inibidor da protease (NPI). As características principais encontradas eram: uma população de pacientes jovem (idade média 41 anos em ambos os grupos), composta na maior parte por indivíduos masculinos (74,3% WPI e 51,4% NPI) com fatores de risco precedentes para ambas as infecções (WPI 93,2% e NPI 89,2%). Os achados mais significativos incluíram doença definidora de AIDS (WPI 18,9% e NPI 13,5% dos casos), nível elevado de enzimas hepáticas (WPI: SGOT 52.1 e NPI 53.2), ausência de sintomas relacionáveis à doença hepática (16.2% para ambos os grupos), CD4 contagem média 350 para ambos os grupos (WPI 362.2 e NPI 378.1), fibrose predominantemente de baixo grau em ambas as populações (0-2 em 63,6% de pacientes de WPI e em 80% de pacientes de NPI), com atividade necro-inflamatória que varia de 5-7 em 51.3% e em 42,9% de pacientes de WPI e de pacientes de NPI, respectivamente. Foi concluído que uma nova biópsia hepática deveria ser executada em todos os pacientes para determinar melhor qual a diferença no avanço da doença em ambos os grupos.