Biological behavior of magnesium-substituted hydroxyapatite during bone repair

The aim of this study was to analyze the biological behavior and osteogenic potential of magnesium (Mg) substituted hydroxyapatite (HA) microspheres, implanted in a critical bone defect, considering that this ion is of great clinical interest, since it is closely associated with homeostasis and bone mineralization. For the purpose of this study, 30 rats were used to compose three experimental groups: GI - bone defect filled with HA microspheres; GII - bone defect filled with HA microspheres replaced with Mg; GIII - empty bone defect; evaluated at biological points of 15 and 45 days. The histological results, at 15 days, showed, in all the groups, a discrete chronic inflammatory infiltrate; biomaterials intact and surrounded by connective tissue; and bone neoformation restricted to the borders. At 45 days, in the GI and GII groups, an inflammatory response of discrete granulomatous chronic type was observed, and in the GIII there was a scarce presence of mononuclear inflammatory cells; in GI and GII, the microspheres were seen to be either intact or fragmented, surrounded by fibrous connective tissue rich in blood vessels; and discrete bone neoformation near the edges and surrounding some microspheres. In GIII, the mineralization was limited to the borders and the remaining area was filled by fibrous connective tissue. It was concluded that the biomaterials were biocompatible and osteoconductive, and the percentage of Mg used as replacement ion in the HA did not favor a greater bone neoformation in relation to the HA without the metal.

Genetic parameters for test day somatic cell score in Brazilian Holstein cattle

Selection for lower somatic cell count has been included in the breeding objectives of several countries in order to increase resistance to mastitis. Genetic parameters of somatic cell scores (SCS) were estimated from the first lactation test day records of Brazilian Holstein cows using random-regression models with Legendre polynomials (LP) of the order 3-5. Data consisted of 87,711 TD produced by 10,084 cows, sired by 619 bulls calved from 1993 to 2007. Heritability estimates varied from 0.06 to 0.14 and decreased from the beginning of the lactation up to 60 days in milk (DIM) and increased thereafter to the end of lactation. Genetic correlations between adjacent DIM were very high (>0.83) but decreased to negative values, obtained with LP of order four, between DIM in the extremes of lactation. Despite the favorable trend, genetic changes in SCS were not significant and did not differ among LP. There was little benefit of fitting an LP of an order >3 to model animal genetic and permanent environment effects for SCS. Estimates of variance components found in this study may be used for breeding value estimation for SCS and selection for mastitis resistance in Holstein cattle in Brazil.

Avaliação das características do líquido ruminal, hemogasometria, atividade pedométrica e diagnóstico de laminite subclínica em vacas leiteiras

Este estudo objetivou avaliar as características do líquido ruminal, hemogasometria, atividade pedométrica e ocorrência laminite subclínica, por meio da presença de enfermidades podais secundárias, em vacas leiteiras de alta produção, provenientes de um rebanho comercial. Foram avaliadas 200 vacas holandesas, oriundas da mesma propriedade, localizada na região de Araçatuba, SP, divididas em quatro grupos, sendo estes estabelecidos a partir da produtividade diária. Inicialmente procedeu-se o exame clínico dos animais, seguido da colheita de amostras do líquido ruminal, por meio de sondagem esofágica, sendo este avaliado quanto ao pH, cor, odor, consistência, sedimentação, flutuação e prova de redução pelo azul de metileno. Também foram colhidas amostras de sangue venoso para hemogasometria, além da coleta dos dados da pedometria (número de passos) e produção de leite diária das vacas. Os dados obtidos foram tabulados e submetidos à análise de correlação. Nenhum animal avaliado apresentou alterações no pH ruminal, bem como não foram encontrados distúrbios do desequilíbrio ácido básico, pois os valores de pH sanguíneo, PCO2, TCO2, HCO3- e EB estavam dentro da normalidade, durante a análise hemogasométrica. A pedometria foi efetiva como método de triagem para as vacas acometidas de afecções podais, pois se observou a redução no número de passos devido à dor, correlacionada a menor produção leiteira. Contudo, a identificação destas afecções, somente foi possível mediante exame clínico específico dos dígitos. A ocorrência das afecções podais em 49,5% do rebanho deveu-se aos fatores de riscos presentes na propriedade, como o concreto abrasivo e instalações inadequadas, associados também a possível ocorrência de acidose ruminal subaguda, não diagnosticada pela metodologia utilizada. A correlação entre os valores do pH ruminal, pedometria e hemogasometria se mostrou eficiente para o diagnóstico precoce das afecções podais e também no estabelecimento da etiologia destas enfermidades. A laminite subclínica acometeu primariamente as vacas do rebanho, considerando a etiologia multifatorial desta afecção, ocorrência e distribuição das enfermidades podais diagnosticadas.

Randomized comparative study of radial artery and right gastroepiploic artery in composite arterial graft for CABG

OBJECTIVES

Arterial grafts have been used to achieve better long-term results and improve graft patency in coronary artery bypass grafting. Composite graft was proposed to overcome inconveniences of proximal anastomoses to the aorta and increase the use and surgical options of arterial grafts. However, lack of prospective randomized studies with this kind of grafts is evident. We compare the results of composite Y-grafts of the radial artery (RA) and the right gastroepiploic artery (RGEA) proximally anastomosed to the left internal thoracic artery (LITA) for CABG, evaluated through angiography, in a prospective randomized study.

METHODS

Between August 1998 and November 1999, 60 patients were randomly divided into two groups: group I (GI) received RGEA graft and group II (GII), RA graft. LITA was used to graft the left anterior descending artery and RGEA or RA was placed to obtuse marginal or first diagonal branch. The right coronary artery branches was grafted with saphenous vein graft (SVG) when necessary. All coronary arteries receiving arterial grafts had > or =75% proximal stenosis and diameter > or =1.5 mm.

RESULTS

GI and GII preoperative data were similar, 63 distal anastomoses were performed with the LITA, 32 with the RA and 32 with the RGEA. There were two perioperative deaths (3.3%), one in each group, none related to cardiac causes. Four (6.6%) q-wave myocardial infarctions were found and two (3.3%) patients showed low cardiac output syndrome. Angiography was performed in all surviving patients from the 8th to 15th postoperative day and showed a patency rate of 96.5% (56/58) for LITA, 89.6% (26/29) for RA and 68.9% (20/29) for RGEA, with a statistically significant difference between RGEA and RA (P=0.025).

CONCLUSIONS

Radial artery had better early results than right gastroepiploic artery. Use of the LITA as inflow graft seems not to affect its good patency. Use of the RGEA as composite graft should not be encouraged. Long-term follow-up with objective investigation and randomized trials is required to confirm better results of composite conduits.

Successful one-stage resection of intravenous leiomyomatosis of the uterus with extension into the heart

Intravenous leiomyomatosis of the uterus is a rare neoplasm characterized by nodular masses of benign smooth muscles with intraluminal growth to the inferior vena cava and, in some cases, to the heart. It may cause abdominal and cardiovascular symptoms and is a serious risk of death when it reaches the tricuspid valve. Surgery is the best treatment and must be applied as soon as possible using cardiopulmonary bypass. The authors report a new case that had cardiac involvement and was successfully resected. The symptoms, imaging diagnosis, pathological and histopathological findings, tumors that mismatched the intravenous leiomyomatosis (IVL), and the use of circulatory arrest and deep hypothermia are discussed. A review of the literature is included.

[Subaortic stenosis caused by anomalous chordae tendineae of the mitral valve ("mitral web")]

Patient with subaortic stenosis due to the insertion of anomalous chordae tendineae of the mitral valve in the interventricular septum (mitral web) associated with mitral stenosis with diagnosis made by bidimensional echocardiographic study with Doppler and confirmed by hemodynamic study. The patient was submitted to surgical treatment. The anomalous cords were resected and the mitral valve with severe malformation was replaced by a bioprosthesis. The patient had a uneventful recovery and echocardiographic evaluation showed an outflow tract without obstruction, with no gradient, with remnants of the papillary muscles and normo-functioning bioprosthesis.

[Intrapericardial diaphragmatic hernia associated with atrial septal defect]

The authors report the case of a patient with atrial septal defect who was submitted to surgical treatment when an intrapericardial hernia was found. The septal defect was closed with a bovine pericardial patch and the hernia with a pediculated autogenous pericardial graft. They discuss several aspects of the classification of the hernia, its association with other anomalies, embryogenesis, pathophysiology, prognosis and surgical correction.

Zymosan-induced experimental hypersensitivity pneumonitis in rabbits

An experimental model of hypersensitivity pneumonitis is presented. New Zealand white rabbits, previously immunized against yeast-derived zymosan, reacted to intratracheal challenge developing extensive pneumonitis. The lesions healed in a few weeks. Control animals challenged with inert particulate material (latex beads) or suspending fluid (PBS-Mg++) did not show pulmonary inflammation. Nonimmunized rabbits developed only transient pneumonitis after zymosan challenge. This reaction was clearly different from that seen in the group of immunized animals. The model reveals that biologically active substances such as zymosan, which is able to activate the alternate pathway of complement and mononuclear phagocytes, requires an active immune state in order to cause significant tissue damage. Isolated exposure to this kind of substance may not be sufficient to cause lung disease.