Use of a titanium device in lateral sinus floor elevation: an experimental study in monkeys

Aim: To evaluate the effect of a space-maintaining device fixed to the lateral wall of the maxillary sinus after the elevation of the sinus mucosa on bone filling of the sinus cavity. Material and methods: Immediately after the elevation of the maxillary sinus Schneiderian membrane accomplished through lateral antrostomy in four monkeys, a titanium device was affixed to the lateral sinus wall protruding into the sinus cavity to maintain the mucosa elevated without the use of grafting material. The healing of the tissue around the implants was evaluated after 3 and 6 months. Ground sections were prepared and analyzed histologically. Results: The void under the elevated sinus membrane, originally filled with the blood clot, was reduced after 3 as well as after 6 months of healing of about 56% and 40.5%, respectively. In seven out of eight cases, the devices had perforated the sinus mucosa. The formation of mineralized bone and bone marrow amounted to about 42% and 69% after 3 and 6 months, respectively. The connective tissue represented about 53% and 23% of the newly formed tissue after 3 and 6 months, respectively. Conclusions: New bone formation was found below the devices. However, shrinkage of the newly formed tissue was observed both after 3 and 6 months of healing. Hence, the space-maintaining function of the devices used in the present study has to be questioned.

Can we predict which patients will evolve to chronic kidney disease after nephrectomy for cortical renal tumors?

Introduction: While some studies show that patients submitted to radical nephrectomy have a higher risk of developing chronic kidney disease (CKD), some studies report that carefully selected living kidney donors do not present a higher risk for CKD. Here, we aim to study predictive factors of CKD after radical nephrectomy. Materials and Methods: Between January 2006 to January 2010, 107 patients submitted to radical nephrectomy for cortical renal tumors at our institution were enrolled in this study. Demographic data were recorded, modified Charlson-Romano Index was calculated, and creatinine clearance was estimated using abbreviated Modification of Diet in Renal Disease (MDRD) study equation. Pathological characteristics, surgical access and surgical complications were also reviewed. The end-point of the current study was new onset estimated glomerular filtration rate (eGFR) less than 60 and less than 45 mL/minute/1.73 m(2). Results: Age, preoperative eGFR, Charlson-Romano Index and hypertension were predictive factors of renal function loss, when the end-point considered was eGFR lower than 60 mL/minute/1.73 m(2). Age and preoperative eGFR were predictive factors of renal function loss, when the end-point considered was eGFR lower than 45 mL/minute/1.73 m2. Moreover, each year older increased 1.1 times the risk of eGFR lower than 60 and 45 mL/minute/1.73 m(2). After multivariate logistic regression, only age remained as an independent predictive factor of eGFR loss. Conclusion: Age is an independent predictive factor of GFR loss for patients submitted to radical nephrectomy for cortical renal tumors.

Percutaneous Nephrolithotomy in Obese Patients: Comparison Between the Prone and Total Supine Position

Background: Percutaneous nephrolithotomy (PCNL) can be performed in the prone or in the supine position. Comparisons between the two techniques in obese patients are rare in the current literature. Methods: The records of obese patients (body mass index >30) who underwent PCNL in the prone or complete supine positions were reviewed. All patients had a noncontrast CT before and after the procedure. Stones were graded according to the Guy stone score and complications according to the Clavien grading. The stone-free rates, operative time, surgical complications, and hospital stay were analyzed. Results: A total of 56 PCNL were performed in 42 patients. Twenty-four PCNL were performed in the prone and 32 in the total supine position. Stone-free rate on the first postoperative day was 50% in the prone and 46.9% in the supine position (P = 1.0). Final stone-free rates were 83.3% and 78.1%, respectively (P = 0.74). Mean operative time was 164.6 minutes in the prone and 120.3 minutes in the supine position (P = 0.0017), and hospital stay was 4.38 and 2.68 days (P = 0.014), respectively. The transfusion rate was 20.8% in the prone and zero in the supine position patients (P = 0.01). Excluding Guy IV stones, transfusion rate was 8.3% in the prone position (P = 0.1). Significant surgical complications rate was 12.5% in the prone and 3.1% in the supine position (P = 0.302). Conclusion: PCNL performed in the prone or in the complete supine position in obese patients presents similar outcomes. The supine decubitus position has the advantages of a significantly shorter operative time and hospital stay.

Generators of supersymmetric polynomials in positive characteristic

In Kantor and Trishin (1997) [3], Kantor and Trishin described the algebra of polynomial invariants of the adjoint representation of the Lie superalgebra gl(m vertical bar n) and a related algebra A, of what they called pseudosymmetric polynomials over an algebraically closed field K of characteristic zero. The algebra A(s) was investigated earlier by Stembridge (1985) who in [9] called the elements of A(s) supersymmetric polynomials and determined generators of A(s). The case of positive characteristic p of the ground field K has been recently investigated by La Scala and Zubkov (in press) in [6]. We extend their work and give a complete description of generators of polynomial invariants of the adjoint action of the general linear supergroup GL(m vertical bar n) and generators of A(s).

A comparison between diuretics and angiotensin-receptor blocker agents in patients with stage I hypertension (PREVER-treatment trial): study protocol for a randomized double-blind controlled trial

Abstract Background Cardiovascular disease is the leading cause of death in Brazil, and hypertension is its major risk factor. The benefit of its drug treatment to prevent major cardiovascular events was consistently demonstrated. Angiotensin-receptor blockers (ARB) have been the preferential drugs in the management of hypertension worldwide, despite the absence of any consistent evidence of advantage over older agents, and the concern that they may be associated with lower renal protection and risk for cancer. Diuretics are as efficacious as other agents, are well tolerated, have longer duration of action and low cost, but have been scarcely compared with ARBs. A study comparing diuretic and ARB is therefore warranted. Methods/design This is a randomized, double-blind, clinical trial, comparing the association of chlorthalidone and amiloride with losartan as first drug option in patients aged 30 to 70 years, with stage I hypertension. The primary outcomes will be variation of blood pressure by time, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new subclinical atherosclerosis and sudden death. The study will last 18 months. The sample size will be of 1200 participants for group in order to confer enough power to test for all primary outcomes. The project was approved by the Ethics committee of each participating institution. Discussion The putative pleiotropic effects of ARB agents, particularly renal protection, have been disputed, and they have been scarcely compared with diuretics in large clinical trials, despite that they have been at least as efficacious as newer agents in managing hypertension. Even if the null hypothesis is not rejected, the information will be useful for health care policy to treat hypertension in Brazil. Clinical trials registration number ClinicalTrials.gov: NCT00971165

Fatores prognósticos associados ao tratamento cirúrgico da mielorradiculopatia espondilótica cervical

OBJETIVO: Identificar os fatores clínicos dos indivíduos, fatores sociais, ambientais e dos exames de imagem que se correlacionam ao resultado final de melhora neurológica em pacientes submetidos ao tratamento cirúrgico da mielopatia espondilótica cervical. MÉTODOS: A avaliação clínica foi quantificada pela escala deficitária da JOA. Analisamos 200 casos de mielorradiculopatia cervical, operados no HC-FMUSP, no período de janeiro de 1993 a janeiro de 2007. A média de segmento foi de 06 anos e 08 meses. A análise radiológica foi baseada nos critérios de instabilidade de White e scala de Kellgren. RESULTADOS: Em 80% houve melhora, 14% estabilização e em 6% piora do quadro neurológico. A piora neurológica não foi associada com nenhum fator clínico, ambiental ou de imagem. A melhora neurológica foi diretamente proporcional a menor idade na cirurgia, ausência de co-morbidade, sinal de Hoffman, atrofia muscular, hipersinal medular na RNM, menor período de evolução pré-operatório, melhor status neurológico pré-operatório e inversamente proporcional ao diâmetro AP do canal medular e multiplicidade de compressões. Identificou-se associação com o tabagismo. Mais de 70 anos, evolução superior a 24 meses, atrofia muscular, pontuação JOA igual ou inferior a sete pontos e diâmetro AP do canal inferior ou igual a seis mm não foram associado à melhora.