The combined effects of binder addition and different sintering methods on the mechanical properties of bovine hydroxyapatite.

Hydroxyapatite (HA) from bovine bones has been used as a biomaterial in dentistry due to its biocompatibility and bioactivity. However, dense HA bioceramics still present inadequate properties for applications that require high mechanical performance, such as infrastructure. Microstructural reinforcements and control of ceramic processing steps are methods to improve these shortcomings. The present study assessed the effects of polyvinyl butyral (PVB) addition in combination with two sintering methodologies (2-step and conventional), on the mechanical properties of polycrystalline bovine HA bioceramics. The samples were divided into four groups (with 15 samples per group): conventional sintering with binder (HBC) and without binder (HWC) and 2-step sintering with (HB2) and without binder (HW2). HA was extracted from bovine bones, turned into nanoparticles in a ball mill, and subjected to uniaxial and isostatic pressing into discs, according to ISO 6872 standards. All groups were characterized by x-ray diffractometry (XRD), differential thermal analysis (DTA) and Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and relative density. Besides, mechanical analyses (biaxial flexural strength (BFS) and modulus of elasticity) were also performed. The characterization results demonstrated that adding agglutinants or the sintering method did not affect HA's chemical and structural characteristics. Even so, the HWC group showed the highest mechanical values for BFS and modulus of elasticity being 109.0 (98.0; 117.0) MPa and 105.17 ± 14.65 GPa, respectively. The HA ceramics submitted to conventional sintering and without the addition of binders achieved better mechanical properties than the other groups. The impacts of each variable were discussed and correlated to the final microstructures and mechanical properties.

PP138. Human fetal malformations associated with the use of angiotensin II receptor antagonist.

INTRODUCTION: antagonists of angiotensin II receptor (AAR) are commonly used for the treatment of chronic hypertension in the general population. Some of these pharmacological agents are losartan, candesartan, valsartan and tasosartan. Despite the good response achieved with these drugs in the control of hypertension, all medications that act directly on the renin-angiotensin system should be contraindicated during pregnancy. These drugs have been associated with fetal and neonatal injury, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure and death.Here we report a case of fetal malformations and death associated with the use of losartan. OBJECTIVES: describing the association of fetal malformations and the use of losartan during first and second trimester of pregnancy. METHODS: this is a case report involving a 37-year-old pregnant woman at 26 gestational weeks. This patient had history of chronic hypertension for more than five years that was being regularly treated with Losartan 50mg/day. After her first consultation losartan was promptly discontinued and substituted for methyldopa. However, scan evaluation demonstrated severe oligohydramnios associated with altered fetal biophysical profile and altered Doppler fluxometry (absent diastolic flow at umbilical arteries). Therefore, a cesarean-section was performed after corticoid administration for fetal lung maturation. At first moment some characteristic alterations as fetal limb contractures and craniofacial deformation were detected at the 1007g new-born. This baby went to death 36h after delivery due to severe lung hypoplasia. RESULTS: the autopsy examination revealed renal tubular dysgenesis associated with changes secondary to nephropathy, probably induced by drug (Fig. 1). Associated findings were underdevelopment of bones of the skull with large fontanelles, thymus atrophy and signs of perinatal hypoxia. CONCLUSION: the difficulty of attending basic health assistance was attributed to be associated with this case, as this patient did not have opportunity and sufficient information about the necessity of changing her medication during pregnancy. Apart from this situation, this case report brings good information about the association between antagonists of angiotensin II receptor and human fetal malformations.

[Multiple retroperitoneal neurofibroma. Report of a case]. / Neurofibroma múltiplo retroperitoneal. Relato de um caso.

Tumors of nervous origin in the retroperitoneum are rare without specific symptoms which diagnosis is usually very difficult. The authors report a case of an asymptomatic patient with two benign retroperitoneal neurofibromas, one of them calcified and located near the inferior pole of the left kidney; the other tumor was closely adhered to the pancreatic tail in the supramesocolic region. Both were resected with appropriated surgical margins. The histopathologic and immunohistochemical studies established the correct diagnosis of the lesions. The authors comment the diagnostic tests of these tumors, their possible malignant degeneration and their surgical treatment.

Infecção pelo citomegalovirus em pacientes com sindrome da imunodeficiencia adquirida (AIDS): relacoes clinico-virologicas e anatomopatologicas / Infection by cytomegalovirus in patients with acquired immunodeficiency syndrome (AIDS): clinical, virological and histopathological correlations

Com o objetivo de determinar a prevalencia da infeccao pelo Citomegalovirus (CMV) em pacientes com AIDS, bem como relacionar os achados clinicos virologicos decorrentes desta infeccao com as repercussoes anatomopatologicas, estudamos 50 pacientes adultos atendidos entre abril de 1986 a junho de 1987, em dois hospitais publicos de Sao Paulo (HSP e HSPE). Estes pacientes foram acompanhados clinica e laboratorialmente, por periodo medio de 2 meses com coletas seriadas de sangue, urina e saliva. Foram realizados isolamento do CMV em monocamadas de fibroblastos humanos e testes sorologicos de Imunofluorescencia Indireta (IFI-IgG/IgM) e Reacao Imunoenzimatica (ELISA-IgG). No momento da admissao no estudo 20 por cento (10/50) dos pacientes apresentavam anticorpos IgM CMV especificos e 100 por cento (50/50) deles anticorpos IgG (IFI). Durante o acompanhamento, 5 pacientes inicialmente IgM negativos tornaram-se IgM positivos, sugerindo reativacao ou reinfeccao pelo CMV. O CMV foi isolado de sangue periferico em 12,5 por cento, da urina em 23,2 por cento, da saliva em 21,9 por cento dos pacientes. Exames anatomopatologicos foram realizados em 24 pacientes, correspondendo a 60 por cento dos pacientes que evoluiram para obito durante o periodo de estudo...

[Infection by cytomegalovirus in patients with acquired immunodeficiency syndrome (AIDS): clinical, virological, and histopathological correlations]. / Infecção pelo citomegalovírus em pacientes com síndrome da immunodeficiência adquirida (AIDS): relações clínico-virológicas e anatomopatológicas.

Between April 1986 and June 1987, 50 patients meeting the CDC criteria for AIDS were studied for serological and virological evidence of CMV infection. Attempts for virus isolation from peripheral blood, urine and saliva were performed in cell culture lines of human foreskin fibroblasts and CMV specific IgG and IgM were assayed by IFI and IgG by ELISA. A total of 121 blood, 119 urine and 96 saliva samples were collected. During the study period viremia was noted at least once in 12.5%, viruria in 23.2%, and excretion in saliva in 21.9%. When admitted in the study, 20% (10/50) of the patients had anti-CMV IgM antibodies and 100% (50/50) of them had IgG anti-CMV antibodies (IFI). Five of the 40 patients IgM negative at admission presented anti-CMV IgM antibodies during the study, suggesting CMV reactivation or reinfection. Active CMV infection based on virus isolation and/or IgM positivity was demonstrated in 60% of the patients. Histopathological studies were performed in 24 patients. CMV was found in 50% of the autopsies, mainly in the digestive system, lungs and adrenals. There was no correlation between clinical, virological (serology and isolation) and histopathological diagnosis.

W-plastic rotation flap to cover nasal defect.

Keeping in mind the direction of the relaxed skin tension lines (RSTL), we used a local W-plastic rotation skin flap from the cheek to cover a large nasal defect resulting from the excision of a benign skin lesion. This technique, first described by Imre [7], is superior to the direct single-pedicle advancement flap from the cheek, or to any nasolabial flap, for repair of such nasal defects.

[Necroscopic findings in patients with acquired immunodeficiency syndrome]. / Achados necroscópicos em pacientes com síndrome da imunodeficiência adquirida.

STUDY OBJECTIVE: The summaries of clinical data and the autopsy materials of 58 patients who died of acquired immunodeficiency syndrome were reviewed to study the spectrum of the pathologic features of this disease in a general hospital. Histologic sections of all organs were routinely obtained. RESULTS: The most affected organs were the lungs and encephalo, those responsible for the immediate cause of death. There were 11 types of microorganisms and 3 types of tumors. Among the microorganisms, the most frequent was the cytomegalovirus and, among tumors, Kaposi's sarcoma. The microorganisms were frequently associated, mainly in the central nervous system. There was also an association of microorganisms with tumors. Many patients presented with suppurative inflammation. Besides these lesions, a lymphocytic depletion of lymphoid organs was observed. CONCLUSIONS: The spectrum of pathologic changes in AIDS is vast, and pathologists should be aware of this fact to accurately diagnose the lesions they find. The morphologic lesions are neither unique nor specific for this syndrome, but in this clinical and immunologic setting they are characteristic. It became clear that several microorganisms and tumors sometimes can only be discovered by autopsy, which is an irrefutable proof that despite the modern technology, autopsy is unavoidable for the knowledge of the pathogeny of a disease.

Timing of scar revision techniques.

In attempting to prevent or to treat unsatisfactory linear scars by the utilization of one of three scar revision techniques, it is important that the surgeon realizes that there are factors beyond his control and factors under his control. This article reviews the current procedures available for scar revision.

Relaxed skin tension lines.

In order to obtain the least scarring following a surgical procedure, it is crucial that the surgeon always consider the direction of the relaxed skin tension lines involved in the procedure and attempt to obtain a scar that follows that direction as much as possible. No other factor (except the region where the surgery is to be performed) is as important in obtaining an acceptable scar, including the too frequently heralded factor, surgical technique. This article deals with the determination and surgical application of the relaxed skin tension lines.

Sad pleats.

A surgical technique is presented for the correction or improvement of the unaesthetic pleat that arises from the commissures of the mouth and gives the patient a sad look.

Unsatisfactory forehead scar following face lift.

The W-plasty scar revision technique has been found to be effective in the repair of the difficult and cosmetically unsatisfactory hairline scar following the ill-advised face lift technique that excises forehead skin.