Tobacco, containing nicotine as the principal pharmacologically active chemical, has been identified as being a risk factor for the development of osteoporosis. Thirty-two male Wistar rats of two months of age were castrated or sham operated to evaluate the effects of long-term administration (four months) of nicotine in drinking water (9.0 mg/kg/day). The presence of cotinine in urine confirmed successful delivery of nicotine. The bones were tested mechanically by a three point bending test in a Mini Bionix (MTA) testing system. The bones from castrated rats were characterized by a reduction in bone density as well as ash, calcium and phosphate content. Castration significantly altered mechanical properties of bone (9%) and femoral cortical thickness. When intact rats were treated with a high dose of nicotine, nicotine had negative effect on tibial bone density as well as ash, calcium, phosphate content and significantly altered the mechanical properties of bone (12%) and femoral cortical thickness compared to intact animals. Nicotine itself does not exert any anti-androgenic effect and does not produce changes in the weight of seminal vesicles. Nicotine-induced bone loss is associated with high bone turnover in the male rats as expressed by increased TrACP and B-ALP. When castrated rats were treated with the high dose of nicotine the changes in bone density resulting from castration were not further potentiated. These results document the efficacy of nicotine at high doses to cause bone loss and loss of bone mechanical strength in intact rats. The results of the present study may be interpreted as supporting the hypothesis of nicotine as a risk factor for osteoporosis.

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Castration of male rats leads to increased bone turnover and osteopenia. This study was conducted to examine the effects of the aminobisphosphonate alendronate on castration-induced bone changes. Bisphosphonates are drugs that inhibit bone turnover by decreasing the resorption. Since they suppress bone remodeling, they may also prevent the repair of microdamage and decrease bone strength. Although the mechanical properties of bones are directly related to the determination of fracture risk, bisphosphonate effects on the related variables have scarcely been investigated. Twenty-four male Wistar rats at two months of age were castrated or sham-operated to evaluate the effects of long-term administration (six months) of sodium alendronate at a dose of 1 mg/kg/day. The bones were tested mechanically by a three-point bending test in a Mini Bionix (MTS) testing system. High bone remodeling seen in castrated rats expressed by increased TrACP and B-ALP was suppressed by alendronate administration. Bone from castrated rats was characterized by a reduction in bone density as well as ash, calcium and phosphate content. Castration significantly altered mechanical properties of bone and femoral cortical thickness. When castrated rats were treated with high dose of alendronate, the changes in bone density resulting from castration were entirely prevented, and mechanical analysis revealed preserved mechanical strength of femur and cortical thickness. We conclude that castration induces cortical bone loss associated with high bone turnover in the male rat, and this bone loss can be prevented by alendronate through the inhibition of osteoclastic activity, while preserving the mechanical properties of bone. These results document the efficacy of alendronate, even at high doses, in preventing bone loss, loss of bone mechanical strength, and the rise in biochemical bone turnover indicators due to castration in rats, and raises the possibility that a alendronate could be equally effective in humans.

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SUMMARY A 20‐year‐old woman with myelomeningocele presented with acute right‐ear pain and right arteriovenous malformation (AVM) involving the right side of the upper cervical cord and brainstem. The woman also had two epidermal nevi at the same site as the spinal cord AVMs. There has been no previous report of an association of myelomeningocele, spinal cord AVMs and epidermal nevi syndrome. The same location of the nevus and spinal cord AVMs, with a proposed common pathogenesis, raise the possibility that the association may be more than chance occurrence. Spinal cord AVMs should be considered in patients with myelomeningocele and similar clinical features. RÉSUMÉ Syndrome associani myéloméningocèle, malformation médullaire artério veineirse ei naevi épidermiques: une association possible rare II fut observé chez une jeune femme de 20 ans avec myéloméningocèle, une douleur aigue de I'oreille droite avec hémiplégie droite qui s'améliora dans un premier temps puis s'aggrava. La chirurgie, faite après IRM. montra une importante malformation artérioveineuse (AVM) impliquant le cǒté droit de la moelle cervicale supérieure et le tronc cérébral. La patiente également deus naevi épidermiques du cǒté de I'AVM médullaire. II n'a pas été publié antérieurernent d'association entre un myéloméningocèle. une AVM médullaire et des naevi épidermiques. La localisation identique des naevi et des AVMs médullaires, avec une pathogénie proposée commune, fait penser que I'association pourrait ne pas ětre fortuite. II faudrait évoquer des AVMs médullaires en cas de myéloméningocèle avec des manifestations cliniques comparables. ZUSAMMENFASSUNG Myeloineningocele, spinal arteriovenöse Miβbildurigen und Hauinaevus: ein seltener Symptomenkomplex? Bei einer 20‐jährigen Frau mit Myelorneningocele traten plötzlich Schmerzen im rechten Ohr und eine rechtsseitige Hemiplegie auf, die sich erst besserten, dann aber progredient verschlechterten. Nach MRI Untersuchung wurde eine Operation durchgeführt, bei der sich eine groβe arteriovenöse Miβildung (AVM) auf der rechten Seite des cervikalen Rückenmarks und des Hirnstarnrns fand. Die Frau hatte auβerdem zwei Hautnaevi im Bereich der AVMs des Rückenmarks. Es gibt bisher keinen Bericht über einen Zusammenhang zwischen Myelomeningocele. AVMs des Rückenmarks und Hautnaevi. Dieselbe Lokalisation von Hautnaevus und AVMs des Rückenmarks mit wahrscheinlich identischer Pathogenese läβt daran denken, daβ es sich nicht nor um ein zufälliges Zusammentreffen dieser Symptonie handelt. Bei Patienten mi1 Myelomeningocele und ähnlichen klinischen Symptomen sollte an AVMs des Ruckemarks gedacht werden. RESUMEN Mielometiingocele, malformación arteriovenosa espinal y sindrotne de nevus epidérmico: ima posible rare asociación? Una mujer de 20 años con mielomeningocele sufrió un dolor aguda en el oido y una hemiplejia derecha que mejoró, pero posteriorrnente se deterioró. La cirugía, tras una IRM, reveló una gran anornalía arteriovenosa (MAV) que afectaba el lado derecho de la parte aha d...