Comparison of effects of chronic administration of naloxone and naloxonazine upon food intake and maintainance of body weight in rats.

A comparison of the effects of the short-acting opioid antagonist naloxone, with the irreversible and highly-specific mu-1 antagonist naloxonazine, has categorized the mediation of opioids in some forms of feeding into mu-1 and non-mu-1 components. The mu-1 sites have been implicated in free-feeding, deprivation-induced feeding and morphine-induced hyperphagia, based upon their sensitivity to both naloxone and naloxonazine. However, the ability of naloxone, but not naloxonazine to inhibit feeding, induced by either 2-deoxy-D-glucose glucoprivation, ethylketocyclazocine, dynorphin or (D-ala2., D-leu5.)-enkephalin implies the existence of non-mu-1 opioid receptor mechanisms in these responses. The present study compared the effects of the daily administration of naloxone and naloxonazine (10 mg/kg, i.v.) in rats in three different types of maturational or dietary situations. In adult rats, naloxonazine and naloxone significantly reduced body weight (7% and 4%, respectively) and food intake (21% and 13%, respectively) over 14 days. These effects were more pronounced in adolescent rats where naloxonazine and naloxone significantly reduced the gain in body-weight (53% and 33%, respectively) and food intake (24% and 15%, respectively) over 14 days. In the adolescent rats, the effects of naloxonazine were significantly greater than those of naloxone. In contrast, chronic treatment with neither naloxone nor naloxonazine altered body weight or food intake of rats made obese by dietary manipulations and left on that diet during treatment with antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)

[Myorelaxants in pediatric anesthesia]. / I miorilassanti in anestesia pediatrica.

The response to muscle relaxants and the dose required change during growth from birth to adolescence. Some physiological factors such as development of neuromuscular junction, the different distribution of the muscle fibres, and the extracellular fluid compartment affect the non depolarizing muscle relaxant (NDMR) ED 95, onset time and recovery time. Infants under 1 year of age are more sensitive to the NDMR and need less drug; children aging more than 1 year are more resistant and need a larger amount of drug; the reversal of the neuromuscular blockade before extubation, is extremely important especially in infants with long-acting agents.

[Paratesticular rhabdomyosarcoma: presentation of a case load and considerations on the current therapeutic management]. / I rabdomiosarcomi paratesticolari: presentazione della casistica e considerazioni sugli attuali atteggiamenti terapeutici.

The Authors report their experience in the management of paratesticular rhabdomyosarcomas observed in the last 5 years (3 cases). Clinical and instrumental findings are analyzed; their therapeutic planes and suggestions of National Protocol RMS 88 are compared.