Outcome of patients with diabetes with negative percutaneous bone biopsy performed for suspicion of osteomyelitis of the foot.

AIMS: To assess the outcome of patients with diabetes with suspicion of osteomyelitis of the foot who had undergone a percutaneous bone biopsy that yielded negative microbiological results, with focus on the occurrence of osteomyelitis at the biopsied site. METHODS: Medical charts of adult patients with diabetes with a negative percutaneous bone biopsy were reviewed. Patients' outcome was evaluated at least 2 years after the initial bone biopsy according to wound healing, the results of a new bone biopsy and bone imaging evaluation when applicable. RESULTS: From January 2001 to January 2008, 41 patients with diabetes (30 men/11 women; mean age 58.1 ± 9.6 years; mean diabetes duration 15.8 ± 6.7 years) met study criteria. Osteomyelitis was suspected based on combined clinical and imaging diagnostic criteria. On follow-up at a mean duration of 41.2 ± 22.5 months post-bone biopsy, 16 patients had complete wound healing (39.0%). Of the 25 other patients, 15 had a new bone biopsy performed, six of which yielded positive microbiological results, and among the 10 patients who neither healed nor underwent bone biopsy, comparative radiography of the foot showed a stable aspect of the biopsied site in six of them, for whom the data were available. Finally, osteomyelitis of the foot at the site where the initial bone biopsy had been performed was confirmed during follow-up in six patients (14.6%) and was suspected in four additional patients (9.7%). CONCLUSIONS: The results of the present study suggest that, of patients with diabetes with the suspicion of osteomylelitis and a negative percutaneous bone biopsy, only one out of four will develop osteomyelitis within 2 years of the biopsy.

Operant thermoregulation of rats with anterior hypothalamic lesions.

The relative importance of different effector mechanisms of thermoregulation may change depending on their availability. Intact rats make only limited use of a learned response on a cold ambient temperature stimulus, and rely almost entirely on autonomic regulatory functions. After destruction of the anterior hypothalamus, rats exhibit a reduced thermoregulatory capacity; i.e. body temperature drops in the cold and rises in the heat. Under this situation a conditioned operant behavior (lever pressing for increasing or decreasing ambient temperature) becomes an important factor to keep body temperature almost constant. Receptor blockers of some putative transmitters in central thermoregulatory pathways influence thermoregulation. Phentolamine induces hypothermia in intact rats in the cold. Hypothalamic lesions are additive in effect with with the drug. Pimozide has no effect neither in the cold nor in the heat intact and lesioned rats. Biperiden in the heat reinforces hyperthermia in intact and lesioned rats as well; in the cold the drug is ineffective. Performance of lesioned rats in an operant pain titration procedure does not differ from intact rats.