The effects of adenosine 5'-triphosphate (ATP) on human and mouse skeletal muscle fibres in primary culture were investigated. ATP-evoked changes in intracellular calcium concentration ([Ca(2+)](i)) were measured and compared with those induced by agonists of the nicotinic acetylcholine (Ach)- and P2X purinoreceptors. While ATP was effective on both myoblasts and multi-nucleated myotubes in the micromolar range, Ach failed to induce any change in [Ca(2+)](i) at early stages of development. In contrast, myofibres with peripheral nuclei showed little response to ATP but responded to Ach with a large change in [Ca(2+)](i). The responsiveness of the myotubes to Ach paralleled that to potassium. The removal of external calcium abolished the response to ATP. P2X receptor agonists mimicked the response to ATP with the order of potency being ATP>2',3'- O-(4-benzoyl)-benzoyl-ATP>beta,gamma-methylene-ATP>alpha,beta-methylene-ATP. Under voltage-clamp conditions ATP induced an inward current that showed little inactivation. These results are consistent with the existence of P2X receptor-mediated signal transduction pathway in cultured mammalian skeletal muscle cells.
After evaluating the results, we determined that the most likely place for the rotational axis is on the median-sagittal plane, in the anterior portion of the spinal canal.
It has recently been postulated that thrombophilia may have a role in the aetiology of Perthes' disease. The published reports, however, remain conflicting. In this study a retrospective analysis of the coagulation parameters was made in 47 patients with Perthes' disease and the results compared with the clinical data. Five patients with Factor V Leiden mutation were found (10.6%) and surprisingly four of them had a homozygous pattern. These four patients showed the most severe form of the disease, Catterall group IV, with flattening of the entire epiphysis, involvement of the metaphysis, shortening and broadening of the femoral neck, trochanteric overgrowth and developed mushroom-shaped aspherical laterally displaced femoral heads in dysplastic acetabula. We would like to suggest that the homozygous form of Factor V Leiden mutation has some role in the clinical course of Perthes' disease and particularly its most severe form.
Bone replacement and the use of bone supplementary biological substances have become widespread in clinical practice. Although autografts have excellent properties, their limited availability, difficulties with shaping and donor site morbidity have made allografts a viable and increasingly preferred alternative. The main drawback of allografts is that the preparation destroys osteogenic cells and results in denaturation of osteoinductive proteins. Serum albumin is a well-known constituent of stem cell culture media and we found that lyophilizing albumin onto bone allografts markedly improves stem-cell attachment and bone healing in animal models thus replacing some of the osteoinductive potential. As a first step in the clinical introduction of albumin coated grafts, we aimed to test surgical handling and early incorporation in aseptic revision arthroplasty in humans. We selected patients who needed large structural allografts and the current operation was the last attempt at preserving a moving joint. In a series of 10 cases of hip and knee revision surgery we did not experience any drawbacks of the albumin-coated grafts during handling and implantation. Twelve months radiographic and SPECT-CT follow-up showed that the graft was well received by the host and active remodelling was observed. The lack of graft-related complications and the good 1-year results indicate that controlled trials may be initiated in more common bone grafting indications where long-term effectiveness can be evaluated.
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