Chorioallantoic and yolk sac placentation in Thrichomys laurentinus (Echimyidae) and the evolution of hystricognath rodents

The evolutionary history of Hystricognathi is associated with major transformations in their placental system. Data so far indicate that key characters are independent from size dimensions in medium to very large species. To better understand the situation in smaller species, we analyzed placental development in a spiny rat, Thrichomys laurentinus. Fourteen individuals ranging from early implantation to near term were investigated by histology, immunohistochemistry, proliferation activity and electron microscopy. Placentation in Thrichomys revealed major parallels to the guinea pig and other hystricognath rodents with respect to the early and invasive implantation, the process of trophoblast invasion, the internal organization of the labyrinth and the trophospongium as well as the establishment of the complete inverted yolk sac placenta. In contrast to systematically related small-sized species, the placental regionalization in Thrichomys was characterized by a remarkable lobulated structure and associated growing processes. Reverse to former perspectives, these conditions represented ancient character states of hystricognaths. The subplacenta was temporarily supplied by both the maternal and fetal blood systems, a rare condition among hystricognaths. The extraplacental trophoblast originating from the subplacenta was partly proliferative in mid gestation. In conclusion, the presented results indicated that only minor variations occurred in small-sized hystricognath species, independent of their systematic interrelationships. Previous views were supported that placentation in hystricognaths followed an extraordinary stable pattern, although the group had distinct habitats in South America and Africa that were separated 30-40 million years ago. J. Exp. Zool. (Mol. Dev. Evol.) 318:13-25, 2012. (C) 2011 Wiley Periodicals, Inc.

Consanguineous unions and the burden of disability: A population-based study in communities of Northeastern Brazil

Objectives: The aim of this study was to identify communities at high risk of transmitting recessive genetic disorders by measuring levels of endogamy and offspring's rate of disabilities. Methods: In a house-to-house population based-survey in the state of Paraiba, 20,462 couples were interviewed regarding kinship relation, number of siblings and offspring affected by mental or physical disabilities. Results: The rate of consanguineous unions in the communities ranged from 6.0% to 41.14%, showing an average value of 20.19% +/- 9.13%. The overall average inbreeding coefficient (F) was 0.00602 +/- 0.00253, ranging from 0.00134 to 0.01182. Communities situated on the backlands had an increased average value of F compared to those closer to the seashore (P = 0.024). The average rate of disabled offspring varied from 2.96% +/- 0.68% for unrelated unions to 10.44% +/- 16.86% for related couples at the level of double first cousins or uncleniece. The Spearman correlation coefficient between the overall rate of disabled offspring from all couples together and F was 0.510 (P < 0.01). Conclusion: Inbreeding increases the risk of disability which is unevenly distributed, varying considerably even in neighboring communities with similar Human Development Index and population density. Higher inbreeding communities are mostly located on the more economically underdeveloped backlands than on the coastal region. The identification of communities at high risk for genetic disorders could serve as basis for the establishment of Community Genetics programs. Am. J. Hum. Biol., 2012. (C) 2012 Wiley Periodicals, Inc.

Relationship Between Oral Health-Related Quality of Life and the Position of the Lower Third Molar: Postoperative Follow-Up

Purpose: The aim of this study was to verify possible associations between oral health-related quality of life (QoL) and the position of the lower third molar among patients undergoing lower third molar surgery during the first postoperative week. Materials and Methods: We performed an interventional prospective study of 86 patients for whom the preoperative treatment plan included the removal of 2 third molar teeth from the same side in a 1-time procedure. The patients were divided into 2 groups depending on the position of the lower third molar. QoL was evaluated before and after the surgical procedure (during the first 7 days) with the Oral Health Impact Profile (OHIP) 14 questionnaire. Data were treated according to Stata 10.0 (StataCorp, College Station, TX). Variables were evaluated by use of split-plot analysis of variance for the repeated-measures analysis to identify the association between QoL and the position of the lower third molar. Results: Patients can have deterioration in their QoL immediately after surgery, especially during the first and second postoperative days, and subsequently show rapid improvement. The variation in the total OHIP score during the days after surgery was significant, whereas a decrease in QoL was observed immediately after the procedure (P = .001), which returned to initial value (preoperative) levels after the sixth postoperative day. The OHIP domains with higher scores (ie, those that had an impact) were physical pain, psychological discomfort, and physical disability (domains 2, 3, and 4, respectively). Conclusions: Teeth considered to be associated with technical difficulties for extraction based on their position had a higher score on the OHIP-14 questionnaire and worse health-related QoL score. QoL outcomes may be as important as clinical signs in decisions regarding third molar extractions. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:779-786, 2012

Frequency of human platelet antigens in oncohematological patients with thrombocytopenia and the probability of incompatibility to platelet transfusions

OBJECTIVE: The objective of this study was to evaluate the frequencies of human platelet antigens in oncohematological patients with thrombocytopenia and to analyze the probability of their incompatibility with platelet transfusions. METHODS: Platelet antigen genotyping was performed by sequence-specific primer polymerase chain reaction (SSP-PCR) for the HPA-1a, HPA-1b, HPA-2a, HPA-2b, HPA-3a, HPA-3b, HPA-4a, HPA-4b, HPA-5a, HPA-5b; HPA-15a, HPA-15b alleles in 150 patients of the Hematology Service of the Hospital das Clínicas (FMUSP). RESULTS: The allele frequencies found were: HPA-1a: 0.837; HPA-1b: 0.163; HPA-2a: 0.830; HPA-2b: 0.170; HPA-3a: 0.700; HPA-3b: 0.300; HPA-4a: 1; HPA-4b: 0; HPA-5a: 0.887; HPA-5b: 0.113; HPA-15a: 0.457 and HPA-15b: 0.543. CONCLUSIONS: Data from the present study showed that the A allele is more common in the population than the B allele, except for HPA-15. This suggests that patients homozygous for the B allele are more predisposed to present alloimmunization and refractoriness to platelet transfusions by immune causes. Platelet genotyping could be of great value in the diagnosis of alloimmune thrombocytopenia and to provide compatible platelet concentrates for these patients.

Stability boundary characterization of nonlinear autonomous dynamical systems in the presence of saddle-node equilibrium points

A dynamical characterization of the stability boundary for a fairly large class of nonlinear autonomous dynamical systems is developed in this paper. This characterization generalizes the existing results by allowing the existence of saddle-node equilibrium points on the stability boundary. The stability boundary of an asymptotically stable equilibrium point is shown to consist of the stable manifolds of the hyperbolic equilibrium points on the stability boundary and the stable, stable center and center manifolds of the saddle-node equilibrium points on the stability boundary.