Binding of fibronectin to phospholipid vesicles.

Human plasma fibronectin, a membrane-associated protein involved in cell-cell adhesion and growth control, binds tightly to phospholipid vesicles of various compositions, as shown by density gradient centrifugation. The binding occurs in the absence of other proteins, sugars, or divalent cations and results in extensive aggregation of the vesicles. Circular dichroism spectroscopy demonstrated that the protein when associated with vesicles adopts a different conformation from that which it adopts in aqueous solution. The vesicle conformation results from a specific interaction and not merely a hydrophobic effect since it also differs substantially from the conformation of the protein in several detergents. Thus, fibronectin is not only capable of binding to lipid vesicles, but the binding induces both a conformational change in the protein and a structural change (aggregation) in the vesicles, which could be related to its role in cell-cell interactions. While these studies do not constitute proof that lipid molecules are the physiological sites of attachment for fibronectin, they do demonstrate that an intermediate receptor need not necessarily be involved to account for the binding properties.

Experimental determination of bone cortex holding power of orthopedic screw.

Cylindrical specimens of bone measuring 15 mm in diameter were obtained from the lateral cortical layer of 10 pairs of femurs and tibias. A central hole 3.2 mm in diameter was drilled in each specimen. The hole was tapped, and a 4.5 mm cortical bone screw was inserted from the outer surface. The montage was submitted to push-out testing up to a complete strip of the bone threads. The cortical thickness and rupture load were measured, and the shear stress was calculated. The results were grouped according to the bone segment from which the specimen was obtained. The results showed that bone cortex screw holding power is dependent on the bone site. Additionally, the diaphyseal cortical bone tissue is both quantitatively and qualitatively more resistant to screw extraction than the metaphyseal tissue.

[Functional rehabilitation of degenerative tendinous injuries of the shoulder]. / Reabilitação funcional das lesões tendinosas degenerativas do ombro.

We studied 60 shoulders in a group of 58 patients, with injuries of shoulder tendons. Thirty-one patients presented impingement syndrome, eighteen patients calcareous tendinitis, five patients rotator cuff rupture, three patients bicipital tendinitis and three patients multiple lesions. All of them were submitted to physical therapy: ultra-sound and kinesio-therapy. Good results were obtained in 55% of the patients. Bad results were recorded in women, young people and in patients with calcareous tendinitis.

Study of fracture healing in protein malnutrition.

The present study was designed to assess the effects of nutrition on fracture healing in a controlled animal model. Tibial fractures were studied in 115 Wistar rats divided into four groups: group 1,50 control animals kept on a normal diet; groups 2 and 3, 45 protein-deprived animals, and group 4, 20 animals submitted to protein malnutrition before the fracture and then placed on a normal laboratory diet. The parameters evaluated during the study were: variation in animal weight during the experiment (confirmation of protein malnutrition), fracture healing as determined by bone callus radiology, macroscopic evaluation of bone callus mechanical resistance, and histological fracture examination by common light microscopy after staining with hematoxylin-eosin. The results showed the beneficial effects of protein nutrition support on the healing of lone bone fractures. Callus formation was significantly improved in groups 1 and 4 compared to groups 2 and 3. In groups 1 and 4, callus development was normal, with regular bone tissue formation, whereas in groups 2 and 3 there was a large amount of fibrous-connective tissue with scarce formation of osseous tissue.

[Mechanical study of stiffness in LIM-41 external fixator assemblages submitted to torsion strain]. / Estudo mecânico da rigidez nas montagens do fixador externo LIM-41 submetidas a esforços de torção.

The mechanical stiffness of LIM-41 external fixator assemlages submitted to torsional strain was studied. A condition of unstable fracture was reproduced. The authors evaluated the effect of of Schanz pin configurations, defined as "distal", "standard" and "proximal", and of the distance, 20 mm, 40 mm or 60 mm between the external fixator and the element employed to simulate bone. The authors conclude that stiffer LIM-41 assemblages are obtained if the "standard" or "proximal" configurations are employed, on which some pins are placed near the fracture simulation site, and if the external fixator body is fitted closer to the bone simulating element, having the former variable greater influence over the stiffness coefficient.

[Effect of electromagnetic fields on osteogenesis: an experimental study on rats]. / Efeito do campo magnético na osteogênese: estudo experimental em ratos.

The authors studied experimentally the electromagnetic pulsing field effects in an experimental model in rats, for evaluation of the velocity of consolidation of tibial and fibular fractures. The animals were followed for a period of three weeks under continuous stimulation and there were done radiological evaluation weekly and histological study at the end of the study. There were no histological, clinical or radiological differences between the group of rats submitted to electromagnetic pulsing fields and the control group.

Osteotomia subtrocanterica oblique:um metodo para faciliar seu planejamento e execucao. / Oblique subtrochanteric osteotomy: a simple and more reliable method

Os autores expoem uma modificacao de apresentacao da tabela elaborada por Merle d' Aubigue para facilitar a determinacao grafica do angulo de osteotomia subtrocanterica obliqua do femur. Alem disso, os autores desenvolveram nova tecnica de posicionamento intra-operatorio, para a precisa correcao concomitante do angulo de inclinacao e de declinacao do femur. Assim, por meio de um nomograma, se planeja com precisao todo o ato operatorio, que se torna mais facil e mais confiavel