Supraacetabular insufficiency fractures

Insufficiency fractures in the supraacetabular region were identified in five women, aged 55-83 years. Factors contributing to the diminished resistance of their bones included postmenopausal osteoporosis, steroid therapy, radiation therapy, and rheumatoid arthritis. The supraacetabular fractures were seen on routine radiographs as hazy bands of sclerosis located immediately above and parallel to the acetabular roof. All five patients had additional fractures in the spine or pelvis. Supraacetabular insufficiency fractures may be an unsuspected cause of hip pain, especially in older women.     

Update: current management issues in malignant melanoma

The incidence of melanoma has increased continuously during the last decade. Surgery is the mainstay of therapy but, for patients with thick lesions or regional metastatic lymph nodes, there is a high risk of relapse. For this group of patients, there is no standard therapy or general agreement amongst oncologists. In this article, we review the current management of melanoma with regard to past completed adjuvant trials and open trials. Moreover, we discuss the role of chemotherapy in metastatic melanoma, in particular with attention to the use of fotemustine.     

IL-18-induced CD83+CCR7+ NK helper cells

In addition to their cytotoxic activities, natural killer (NK) cells can have immunoregulatory functions. We describe a distinct "helper" differentiation pathway of human CD56+CD3- NK cells into CD56+/CD83+/CCR7+/CD25+ cells that display high migratory responsiveness to lymph node (LN)-associated chemokines, high ability to produce interferon-gamma upon exposure to dendritic cell (DC)- or T helper (Th) cell-related signals, and pronounced abilities to promote interleukin (IL)-12p70 production in DCs and the development of Th1 responses. This helper pathway of NK cell differentiation, which is not associated with any enhancement of cytolytic activity, is induced by IL-18, but not other NK cell-activating factors. It is blocked by prostaglandin (PG)E2, a factor that induces a similar CD83+/CCR7+/CD25+ LN-homing phenotype in maturing DCs. The current data demonstrate independent regulation of the "helper" versus "effector" pathways of NK cell differentiation and novel mechanisms of immunoregulation by IL-18 and PGE2.     

Activation of plasminogen as a feature in its assay.

Seven laboratories collaborating in a study of two intermediate purity plasminogen preparations (64/23, 63/6) observed that the amount of activator (urokinase or streptokinase) and the time of activation of plasminogen influenced the amount of plasmin generated. Using casein and a synthetic polypeptide (S-2251) as substrates, the authors subsequently showed that complete activation of plasminogen was difficult to achieve without acitivity losses due to plasmin autodigestion. Comparison of the polypeptide subunits (on SDS electrophoresis) of the various plasminogen activation mixtures with their plasmin activity allowed the conclusion that at maximum generation of plasmin from plasminogen, some plasminogen remains in the form of an inactive plasminogen intermediate (PLG-i).     

Modelling the disposable soma theory of ageing

We describe a mathematical model, developed using the Mathematica programming system of the disposable soma theory of ageing. The model makes explicit predictions about the optimal strategies for investment in somatic maintenance versus investments in growth and reproduction and confirms the central prediction of the disposable soma theory that the optimum investment in somatic maintenance is less than what would be required for indefinite longevity. We also describe how the optimal investment in maintenance is affected by varying the parameters that specify the schedules of reproduction and mortality.     

How local community knowledge about malaria affects insecticide-treated net use in northern Ghana

Large-scale trials of insecticide-treated nets (ITNs) throughout Sub-Saharan Africa demonstrated that they reduce child mortality in malaria endemic communities. These encouraging results have generated interest in ITNs as a viable malaria control strategy in many malaria endemic countries. However, regular use of ITNs under routine or non-project conditions has been beset with several problems. This paper explores how local community knowledge about malaria acts as a barrier to the use of ITNs in three settings. We employed structured formal observation and a range of interviewing techniques which included informal interviews, focus group discussions, semi-structured in-depth interviews, and structured survey interviewing. People recognize the term 'malaria' but have limited biomedical knowledge of the disease, including its aetiology, the role of the vector, and host response. Convulsions and anaemia are rarely linked to malaria. The people acknowledged a role for ITNs in nuisance reduction, but not for malaria prevention.     

Terminal Schwann cell structure is altered in diaphragm of mdx mice

The diaphragm muscle of the mdx mouse is a model system of Duchenne muscular dystrophy, since it completely lacks dystrophin and shows severe fiber necrosis and loss of specific muscle force by 4-6 weeks of age. Changes in neuromuscular junction structure also become apparent around 4 weeks including postsynaptic acetylcholine receptor declustering, loss of postsynaptic junctional folds, abnormally complex presynaptic nerve terminals, and muscle fiber denervation. Normally, terminal Schwann cells (TSCs) cap both nerve terminals and acetylcholine receptors at the neuromuscular junction, and play a crucial role in regeneration of motor axons following muscle denervation by guiding axons to grow from innervated junctions to nearby denervated junctions. However, their role in restoring innervation in dystrophic muscle is unknown. We now show that TSCs fail to cap fully the neuromuscular junction in dystrophic muscle; TSCs extend processes, but the organization of these extensions is abnormal. TSC processes of dystrophic muscle do not form bridges from denervated fibers to nearby innervated endplates, but appear to be directed away from these endplates. Adequate signaling for TSC reactivity is present, since significant muscle fiber denervation and acetylcholine receptor declustering are present. Thus, significant structural denervation is present in the diaphragm of mdx mice and the ability of TSCs to form bridges between adjacent endplates to guide reinnervation of muscle fibers is impaired, possibly attenuating the ability of dystrophic muscle to recover from denervation and ultimately leading to muscle weakness.