Testostérone et contrôle central de l’érection

La testostérone orchestre l’organisation périnatale et l’activation adulte des structures nerveuses cérébrales et spinales impliquées dans l’expression du comportement sexuel mâle. Cette revue décrit brièvement les différents effets de la testostérone dans la régulation de la motivation sexuelle et de l’érection, et les modèles génétiques générés, jusqu’à présent, dans le but d’élucider ses mécanismes d’action centraux.

Congenital vascular malformations in the hand and forearm

PURPOSE

To review a single-center experience in the management of symptomatic congenital vascular malformations of the hand and forearm with special attention to embolotherapy.

METHODS

A retrospective chart review was performed to identify patients with vascular malformations referred for arteriography and possible intervention between 1983 and 1998. Arteriography and venography were performed in all patients to differentiate between true high-flow arteriovenous malformations (AVM) and low-flow primary venous malformations (PVM). The clinical and radiological data, procedural results, and follow-up data were retrieved and reviewed.

RESULTS

In a 15-year period, 39 patients (22 men; mean age 22.5 years, range 1-51) had symptomatic vascular lesions diagnosed in the forearm and hand: 21 AVMs, 17 PVMs, and one complex lesion with both AVM and PVM. Thirty-four (87%) lesions were treated with immediate technical success achieved in 31 (91%) cases; 5 (13%) lesions were not amenable to percutaneous treatment. There were no major complications, but 3 embolized AVMs had significant residual flow (81.6% technical success on intention to treat basis). Long-term follow-up ranging to 5 years was available in 26 of the 34 treated patients; the mean symptom-free period was 30 months for the AVM patients and 30.5 months for the PVM group, with an average of 1.5 and 1.2 embolization procedures, respectively.

CONCLUSIONS

Vascular malformations of the hand and forearm are extremely rare lesions that demand a multidisciplinary approach for optimal diagnosis and management. Microembolotherapy with or without surgery has offered the highest level of safety and success to date.

Lipids closely associated with bone morphogenetic protein (BMP)--and induced heterotopic bone formation. With preliminary observations of deficiencies in lipid and osteoinduction in lathyrism in rats

An extensive literature on bone morphogenetic protein (BMP) induced generation and regeneration shows general agreement about one observation. The incidence and quantity of bone were greatest when BMP was delivered with a carrier of various biologic and non biologic polymers. In the present research, neutral lipids either endogenous in demineralized bone matrix (DBM) or exogenous in orign were employed as a delivery system for induced heterotopic bone formation in the rectus muscle in rats. Total neutral lipids including cholesterol were measured by correlated gravimetric and Sudan Black B dye binding methods. The heterotopic bone was measured by computer assisted radiomorphometric and histologic methods. Bone formation was measured by total calcium, DNA-P, and alkaline phosphatase activity. Composites of BMP and neutral lipids, separable from phospholipids by extraction with absolute acetone, were consistently osteoinductive. A significant quantity of the total bone lipid was closely associated with and extractable from the bone matrix non-collagenous protein fraction which had high levels of BMP activity. Lathyritic matrix was very low both in dye binding and osteoinductive activity. These observations suggest the possibility that lipids may serve as a BMP carrier in the process of induced bone development.

Endogenous bone morphogenetic protein: immunohistochemical localization in repair of a punch hole in the rabbit's ear

By means of monoclonal anti-bone morphogenetic protein 2 immunohistochemical methods, endogenous bone morphogenetic protein was observed in the process of generation of heterotopic bone in experimental punch holes in the rabbit's ear. In repair of the punch hole, dermis, subcutaneous connective tissue, and perichondrium proliferated, hypertrophied, and differentiated in the rim within 2 weeks. By 3 to 4 weeks, epidermis grew centripetally down into and across the dorsal and ventral openings and sealed the punch hole. A blastema-like structure consisting of a condensation of the mesenchymal type cells covered the cut ends of the elastic cartilage. The condensation differentiated into chondro-osteoprogenitor cells and hyaline cartilage within 4 to 5 weeks. Within 4 to 6 weeks, sprouting capillaries, macrophages, and monocytes resorbed and replaced hyaline cartilage with a perichondral ring of bone. Anti-bone morphogenetic protein 2 appeared first in the perichondrium, then in the condensation, and later in the chondro-osteoprogenitor cells. A basic assumption was that latent non-reactive bone morphogenetic protein was converted to the anti-bone morphogenetic protein 2-reactive form by injury, inflammation, and proteolysis. The reactive form and various other local factors contributed the temporal and spatial constraints of a morphogenetic field for development of heterotopic bone. The receptors and mechanism of bone morphogenetic protein signal transduction are unknown.