Implant Osseointegration in Circumferential Bone Defects Treated with Latex-Derived Proteins or Autogenous Bone in Dog's Mandible

Background: In sites with diminished bone volume, the osseointegration of dental implants can be compromised. Innovative biomaterials have been developed to aid successful osseointegration outcomes. Purpose: The aim of this study was to evaluate the osteogenic potential of angiogenic latex proteins for improved bone formation and osseointegration of dental implants. Materials and Methods: Ten dogs were submitted to bilateral circumferential defects (5.0 x 6.3 mm) in the mandible. Dental implant (3.3 x 10.0 mm, TiUnite MK3 (TM), Nobel Biocare AB, Goteborg, Sweden) was installed in the center of the defects. The gap was filled either with coagulum (Cg), autogenous bone graft (BG), or latex angiogenic proteins pool (LPP). Five animals were sacrificed after 4 weeks and 12 weeks, respectively. Implant stability was evaluated using resonance frequency analysis (Osstell Mentor T, Osstell AB, Goteborg, Sweden), and bone formation was analyzed by histological and histometric analysis. Results: LPP showed bone regeneration similar to BG and Cg at 4 weeks and 12 weeks, respectively (p >= 3.05). Bone formation, osseointegration, and implant stability improved significantly from 4 to 12 weeks (p <= 2.05). Conclusion: Based on methodological limitations of this study, Cg alone delivers higher bone formation in the defect as compared with BG at 12 weeks; compared with Cg and BG, the treatment with LPP exhibits no advantage in terms of osteogenic potential in this experimental model, although overall osseointegration was not affected by the treatments employed in this study.

Catch-up growth in children after repair of Tetralogy of Fallot

Purpose: To evaluate the growth of children after repair of Tetralogy of Fallot, as well as the influence of residual lesions and socio-economic status. Methods: A total of 17 children, including 10 boys with a median age of 16 months at surgery, were enrolled in a retrospective cohort, in a tertiary care university hospital. Anthropometric (as z-scores), clinical, nutritional, and social data were collected. Results: Weight-for-age and weight-for-height z-scores decreased pre-operatively and recovered post-operatively in almost all patients, most markedly weight for age. Weight-for-height z-scores improved, but were still lower than birth values in the long term. Long-term height-for-age z-scores were higher than those at birth, surgery, and 3 months post-operatively. Most patients showed catch-up growth for height for age (70%), weight for age (82%), and weight for height (70%). Post-operative residual lesions (76%) influenced weight-for-age z-scores. Despite the fact that most patients (70%) were from low-income families, energy intake was above the estimated requirement for age and gender in all but one patient. There was no influence of socio-economic status on pre- and post-operative growth. Bone age was delayed and long-term-predicted height was within mid-parental height limits in 16 children (93%). Conclusion: Children submitted to Tetralogy of Fallot repair had pre-operative acute growth restriction and showed post-operative catch-up growth for weight and height. Acute growth restriction could still be present in the long term.

Genotype by environment interaction for birth and weaning weights of composite beef cattle in different regions of Brazil

The objectives of the present study were to characterize and define homogenous production environments of composite beef cattle in Brazil in terms of climatic and geographic variables using multivariate exploratory techniques and to use them to assess the presence of G x E for birth weight (BW) and weaning weight (WW). Data from animals born between 1995 and 2008 on 36 farms located in 27 municipalities of the Brazilian states were used. Fifteen years of climate observations (mean minimum and maximum annual temperature and mean annual rainfall) and geographic (latitude, longitude and altitude) data were obtained for each municipality where the farms were located for characterization of the production environments. Hierarchical and nonhierarchical cluster analysis was used to group farms located in regions with similar environmental variables into clusters. Six clusters of farms were formed. The effect of sire-cluster interaction was tested by single-trait analysis using deviance information criterion (DIC). Genetic parameters were estimated by multi-trait analysis considering the same trait to be different in each cluster. According to the values of DIC, the inclusion of sire-cluster effect did not improve the fit of the genetic evaluation model for BW and WW. Estimates of genetic correlations among clusters ranged from -0.02 to 0.92. The low genetic correlation among the most studied regions permits us to suggest that a separate genetic evaluation for some regions should be undertaken. (C) 2012 Elsevier B.V. All rights reserved.

Advice on the Management of Ambiguous Genitalia to a Young Endocrinologist from Experienced Clinicians

The birth of a child with ambiguous genitalia is a challenging and distressing event for the family and physician and one with life-long consequences. Most disorders of sexual differentiation (DSD) associated with ambiguous genitalia are the result either of inappropriate virilization of girls or incomplete virilization of boys. It is important to establish a diagnosis as soon as possible, for psychological, social, and medical reasons, particularly for recognizing accompanying life-threatening disorders such as the salt-losing form of congenital adrenal hyperplasia. In most instances, there is sufficient follow-up data so that making the diagnosis also establishes the appropriate gender assignment (infants with congenital adrenal hyperplasia, those with androgen resistance syndromes), but some causes of DSD such as steroid 5 alpha-reductase 2 deficiency and 17 beta-hydroxysteroid dehydrogenase deficiency are associated with frequent change in social sex later in life. In these instances, guidelines for sex assignment are less well established.

Brazilian multicenter study on prevalence of preterm birth and associated factors

Abstract Background The occurrence of preterm birth remains a complex public health condition. It is considered the main cause of neonatal morbidity and mortality, resulting in a high likelihood of sequelae in surviving children. With variable incidence in several countries, it has grown markedly in the last decades. In Brazil, however, there are still difficulties to estimate its real occurrence. Therefore, it is essential to establish the prevalence and causes of this condition in order to propose prevention actions. This study intend to collect information from hospitals nationwide on the prevalence of preterm births, their associated socioeconomic and environmental factors, diagnostic and treatment methods resulting from causes such as spontaneous preterm labor, prelabor rupture of membranes, and therapeutic preterm birth, as well as neonatal results. Methods/Design This proposal is a multicenter cross-sectional study plus a nested case-control study, to be implemented in 27 reference obstetric centers in several regions of Brazil (North: 1; Northeast: 10; Central-west: 1; Southeast: 13; South: 2). For the cross sectional component, the participating centers should perform, during a period of six months, a prospective surveillance of all patients hospitalized to give birth, in order to identify preterm birth cases and their main causes. In the first three months of the study, an analysis of the factors associated with preterm birth will also be carried out, comparing women who have preterm birth with those who deliver at term. For the prevalence study, 37,000 births will be evaluated (at term and preterm), corresponding to approximately half the deliveries of all participating centers in 12 months. For the case-control study component, the estimated sample size is 1,055 women in each group (cases and controls). The total number of preterm births estimated to be followed in both components of the study is around 3,600. Data will be collected through a questionnaire all patients will answer after delivery. The data will then be encoded in an electronic form and sent online by internet to a central database. The data analysis will be carried out by subgroups according to gestational age at preterm birth, its probable causes, therapeutic management, and neonatal outcomes. Then, the respective rates, ratios and relative risks will be estimated for the possible predictors. Discussion These findings will provide information on preterm births in Brazil and their main social and biological risk factors, supporting health policies and the implementation of clinical trials on preterm birth prevention and treatment strategies, a condition with many physical and emotional consequences to children and their families.

Childbearing in adolescence: intergenerational dejà-vu? Evidence from a Brazilian birth cohort

Abstract Background Pregnancy in adolescence tends to repeat over generations. This event has been little studied in middle and low-income societies undergoing a rapid epidemiological transition. To assess this association it is important to adjust for socioeconomic conditions at different points in lifetime. Therefore, the aim of this study is to analyze the independent effect of adolescent childbearing in a generation on its recurrence in the subsequent generation, after adjusting for socioeconomic status at different points in life. Methods The study was conducted on a prospective cohort of singleton liveborn females from the city of Ribeirão Preto, Brazil, evaluated in 1978/79, and their daughters assessed in 2002/04. A total of 1059 mother-daughter pairs were evaluated. The women who had their first childbirth before 20 years of age were considered to be adolescent mothers. The risk of childbearing in adolescence for the daughter was modeled as a function of the occurrence of teenage childbearing in her mother, after adjustment for socio-demographic variables in a Poisson regression model. Results The rate of childbearing during adolescence was 31.4% in 1978/79 and 17.1% in 2002/04. Among the daughters of the 1st generation adolescent mothers, this rate was 26.7%, as opposed to 12.7% among the daughters of non adolescent mothers. After adjustments the risk of adolescent childbearing for the 2nd generation was 35% higher for women whose mothers had been pregnant during adolescence – RR = 1.35 (95% CI 1.04-1.74). Conclusion Adolescent childbearing in the 1st generation was a predictor of adolescent childbearing in the 2nd, regardless of socioeconomic factors determined at different points in lifetime.

Prevalence of enamel defects in permanent teeth of patients with complete cleft lip and palate

Objective: To evaluate the prevalence, types, location, and characteristics of enamel defects in anterior permanent teeth of patients with complete unilateral and bilateral cleft lip and palate, as well as the relation with the cleft. Setting: Hospital for Rehabilitation of Craniofacial Anomalies, Bauru, São Paulo, Brazil. Participants: Eighty patients of both genders, 12 years and older, with unilateral or bilateral cleft lip and palate. Methods: A single examiner carried out clinical examination under artificial light with a dental probe and mirror after drying teeth according to the modified DDE index. Results: Seventy-four of 80 patients presented with at least one tooth affected by enamel defects: 165 of 325 evaluated teeth (50.8%) presented enamel defects, with hypoplasia being the most prevalent (50.7%), followed by diffuse opacity (23.1%) and demarcated opacity (18.4%). The most affected tooth was 21 (36.5%), followed by 11 (34%), located at the middle (40%) and incisal (33%) thirds. Most defects occur at the buccal surface (47.7%), followed by the distal (22.7%), the mesial (19%), and the palatal (10.6%) surfaces. A significant relationship was found between the cleft side and enamel defects. Conclusion: Upper anterior teeth of patients with complete cleft lip and palate present a high prevalence of enamel defects; the highest percentage on the cleft side suggests that the cleft does influence the occurrence of enamel defects in permanent teeth.

Bilateral osteoporotic bone marrow defects of the mandible: a case report

Osteoporotic bone marrow defect of the jaws has been reported as a poorly demarcated radiolucency that affect mainly posterior mandible of middle-aged woman. The incidence of this condition is not exactly established and its pathogenesis remains unknown. An additional unusual case of osteoporotic bone marrow defects occurring bilaterally in the mandibular edentulous regions of a 32-year-old white woman is presented reinforcing its diagnostic criteria and histopathological findings.

Exploring anorganic bovine bone granules as osteoblast carriers for bone bioengineering: a study in rat critical-size calvarial defects

It is known that current trends on bone bioengineering seek ideal scaffolds and explore innovative methods to restore tissue function. In this way, the objective of this study was to evaluate the behavior of anorganic bovine bone as osteoblast carrier in critical-size calvarial defects. MC3T3-E1 osteoblast cells (1x10(5) cells/well) were cultured on granules of anorganic bovine bone in 24-well plates and after 24 h these granules were implanted into rat critical-size calvarial defects (group Biomaterial + Cells). In addition, other groups were established with different fillings of the defect: Blood Clot (negative control); Autogenous Bone (positive control); Biomaterial (only granules) and Cells (only MC3T3-E1 cells). After 30 days, the animals were euthanized and the calvaria were technically processed in order to allow histological and morphometric analysis. It was possible to detect blood vessels, connective tissue and newly formed bone in all groups. Particularly in the Biomaterial + Cells group, it was possible to observe a profile of biological events between the positive control group (autogenous bone) and the group in which only anorganic bovine granules were implanted. Altogether, the results of the present study showed that granules of anorganic bovine bone can be used as carrier to osteoblasts and that adding growth factors at the moment of implantation should maximize these results.

Chitosan-based biomaterials used in critical-size bone defects: radiographic study in rat's calvaria

OBJETIVO: Este estudo avaliou através de imagens radiográficas digitais, a ação de biomateriais de quitosana e de cloridrato de quitosana, com baixo e alto peso molecular, utilizados na correção de defeitos ósseos de tamanho crítico (DOTC)em calvária de ratos. MATERIAL E MÉTODO: DOTCs com 8 mm de diâmetro foram criados cirurgicamente na calvária de 50 ratos Holtzman. Em 10 animais o defeito foi preenchido foram preenchidos com coágulo sanguíneo (controle negativo). Os 40 animais restantes foram divididos de acordo com o biomaterial utilizado no preenchimento do defeito (quitosana de baixo peso e de alto peso molecular, e cloridrato de quitosana de baixo e de alto peso molecular), e foram avaliados em dois períodos experimentais (15 e 60 dias), totalizando 5 animais/biomaterial/período de avaliação. RESULTADO: A avaliação radiográfica foi feita utilizando duas radiografias digitais do crânio do animal: uma tomada logo após o defeito ósseo ser criado e a outra no momento do sacrifício. Nessas imagens, foi avaliada a densidade óssea radiográfica inicial e a final na área do defeito, que foram comparadas. As análises na densidade óssea radiográfica indicaram aumento da densidade óssea radiográfica dos DOTCs tratados para todos os biomateriais testados, em ambos os períodos. Resultados semelhantes foram encontrados no grupo controle. CONCLUSÃO: Conclui-se que os biomateriais de quitosana testados não foram capazes de aumentar a densidade radiográfica em DOTC realizados em calvária de ratos.

The effect of bone allografts combined with bone marrow stromal cells on the healing of segmental bone defects in a sheep model

Background: The repair of large bone defects is a major orthopedic challenge because autologous bone grafts are not available in large amounts and because harvesting is often associated with donor-site morbidity. Considering that bone marrow stromal cells (BMSC) are responsible for the maintenance of bone turnover throughout life, we investigated bone repair at a site of a critically sized segmental defect in sheep tibia treated with BMSCs loaded onto allografts. The defect was created in the mid-portion of the tibial diaphysis of eight adult sheep, and the sheep were treated with ex-vivo expanded autologous BMSCs isolated from marrow aspirates and loaded onto cortical allografts (n = 4). The treated sheep were compared with control sheep that had been treated with cell-free allografts (n = 4) obtained from donors of the same breed as the receptor sheep. Results: The healing response was monitored by radiographs monthly and by computed tomography and histology at six, ten, fourteen, and eighteen weeks after surgery. For the cell-loaded allografts, union was established more rapidly at the interface between the host bone and the allograft, and the healing process was more conspicuous. Remodeling of the allograft was complete at 18 weeks in the cell-treated animals. Histologically, the marrow cavity was reestablished, with intertrabecular spaces being filled with adipose marrow and with evidence of focal hematopoiesis. Conclusions: Allografts cellularized with AOCs (allografts of osteoprogenitor cells) can generate great clinical outcomes to noncellularized allografts to consolidate, reshape, structurally and morphologically reconstruct bone and bone marrow in a relatively short period of time. These features make this strategy very attractive for clinical use in orthopedic bioengineering