Possible Migration and Histopathological Analysis of Injections of Polymethylmethacrylate in Wistar Rats

Objective. To evaluate the possible migration of polymethylmethacrylate after injections in various corporal compartments of Wistar rats. Methods. The experimental work consisted in the injection of PMMA in corporal compartments for later histopathological analysis of the locations of implants and of distant filtering organs. The dose applied in each implant was of 0.2 mL. The animals were divided into groups according to the location of the implant realized: group GB had intradermic injections in the glabella. Group SD had subdermal injections in dorsal subcutaneous tissue cells. Group IP had intraperitoneal injections in the abdomen. Group PD had intramuscular injections in the right rear leg. The rats were sacrificed 30 days after realization of the implants and tissue samples from the lung, liver, spleen, and kidney, and locations of implantation were removed for histopathological analysis. Results. Characteristic microspheres that were compatible with the presence of PMMA in any of the histological slides analyzed were not observed. One animal had an amorphous exogenous substance, with a histiocytic reaction. Twelve of the 16 lungs analyzed had locations of intraalveolar hemorrhaging. Two animals had nonspecific spleen alterations. Conclusion. The histopathological analysis of this study found no PMMA microspheres in any of the tissues analyzed

Margem de segurança: um conceito antigo e relativo

As expressões margem de segurança e margem cirúrgica são usadas freqüentemente como sinônimas, embora tenham significados distintos. A margem de segurança é preestabelecida e faz parte do planejamento cirúrgico. A margem cirúrgica é verificada posteriormente pelo patologista ao exame da peça cirúrgica. Na literatura não existe consenso a respeito da extensão da margem de segurança, sendo ela baseada em uma série de variáveis nem sempre de fácil análise. Por outro lado a cirurgia microscopicamente controlada não utiliza o conceito de margem de segurança e se constitui na forma mais racional de tratamento do câncer cutâneo. Este artigo discorre sobre os fatores determinantes da margem de segurança e da margem cirúrgica, tanto do ponto de vista clínico como do laboratorial, traçando um paralelo com a cirurgia microscopicamente controlada e lançando algumas reflexões importantes sobre a relatividade do conceito de margem de segurança

Discovery and Characterization of Alamandine, a Novel Component of the Renin-Angiotensin System

The renin?angiotensin system (RAS) is a key regulator of the cardiovascular system, electrolyte, and water balance. Here, we report identification and characterization of alamandine, a new heptapeptide generated by catalytic action of angiotensin-converting enzyme-2 angiotensin A or directly from angiotensin-(1?7). To characterize a novel component of the RAS, alamandine. Using mass spectrometry we observed that alamandine circulates in human blood and can be formed from angiotensin-(1?7) in the heart. Alamandine produces several physiological actions that resemble those produced by angiotensin-(1?7), including vasodilation, antifibrosis, antihypertensive, and central effects. Interestingly, our data reveal that its actions are independent of the known vasodilator receptors of the RAS, Mas, and angiotensin II type 2 receptor. Rather, we demonstrate that alamandine acts through the Mas-related G-protein?coupled receptor, member D. Binding of alamandine to Mas-related G-protein?coupled receptor, member D is blocked by D-Pro7-angiotensin-(1?7), the Mas-related G-protein?coupled receptor, member D ligand ?-alanine and PD123319, but not by the Mas antagonist A-779. In addition, oral administration of an inclusion compound of alamandine/?-hydroxypropyl cyclodextrin produced a long-term antihypertensive effect in spontaneously hypertensive rats and antifibrotic effects in isoproterenol-treated rats. Alamandine had no noticeable proliferative or antiproliferative effect in human tumoral cell lines. The identification of these 2 novel components of the RAS, alamandine and its receptor, provides new insights for the understanding of the physiological and pathophysiological role of the RAS and may help to develop new therapeutic strategies for treating human cardiovascular diseases and other related disorders

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved