Prevention of precipitation of phenytoin in an infusion fluid by hydroxypropyl β-cyclodextrin

Injection of phenytoin is often diluted with infusion fluids before administration, which may lead to precipitation of the drug due to changes in pH and/or vehicle. It is not possible to add cyclodextrins to the original injections to prevent precipitation of the drug, because the quantities required would be impractical (>100% w/v). However, from a knowledge of the solubility of phenytoin in cyclodextrin solutions, it is possible to add sufficient amounts of a soluble cyclodextrin to infusion fluids to maintain the solubility of phenytoin after the original injection is diluted to clinical concentrations in the fluid. From solubility measurements, theoretical amounts of hydroxypropyl β-cyclodextrin (HPCD), sufficient to prevent precipitation of phenytoin, were added to 0·9% w/v sodium chloride solution, adjusted to pH 7·0. Phenytoin injection was diluted to clinical concentrations in the cyclodextrin/NaCl solutions. The mixtures, together with analogous mixtures containing phenytoin, but no HPCD, were stored at 25 °C for 3 days. In the presence of the cyclodextrin no precipitates of phenytoin were observed, but in its absence an immediate massive precipitation of phenytoin occurred. This is a flexible method for using soluble cyclodextrins to prevent precipitates of drugs in infusion fluids, provided the cyclodextrin used is not toxic.     

Effect of age and diet on glucose tolerance in Sprague-Dawley rats

Male Sprague-Dawley rats ages 12 and 27 mo were used to evaluate intravenous glucose tolerance. Rats were fed ad libitum a purified diet containing either 33% sucrose and 33% starch or 66% starch, 17.5% casein and 7% fat (g/100 g) for 4 mo. Each animal was fitted with a cannula in the left carotid artery while anesthetized with methoxyflurane and was allowed to recover without food for 10-12 h. A resting blood sample was withdrawn, and then each rat received 1 mL of 50% glucose in saline per kilogram body weight throughout the carotid cannula. The cannula was washed with the rat's blood to remove any excess glucose, and blood samples were taken at 5, 10, 15, 30, 45 and 60 min after infusion. The 12-mo-old rats in both the high sucrose and sucrose-free diet groups had significantly greater resting plasma glucose and insulin concentrations than did their 27-mo-old counterparts. Diet had no effect on resting glucose or insulin levels. Neither age nor diet had a significant effect on plasma glucose or insulin concentrations following the glucose infusion. These data suggest that the pancreatic response to a glucose load is not altered by age or high sucrose diets.     

Transcanal cochlear implantation under monitored anesthesia care.

OBJECTIVE: Given the associated risk of general anesthesia in elderly patients with cardiovascular disease, the authors set out to determine the feasibility of transcanal cochlear implantation under local anesthesia with monitored anesthesia care. METHODS: A 70-year-old man with a history of coronary artery bypass grafting, diabetes mellitus, and an American Society of Anesthesiologists Class III cardiac status underwent cochlear implantation under local with monitored anesthesia care. RESULT: With the described technique and regimen of intravenous remifentanil and dexmedetomidine, the patient tolerated the 60-minute procedure without tachycardia, hyper- or hypotension, or cardiac ischemia. CONCLUSION: Cochlear implantation using the pericanal electrode technique performed under local anesthesia with monitored anesthesia care is possible in patients at risk for undergoing general anesthesia for cochlear implantation.     

Self-mutilation in adolescents.

Self-mutilation is not a new trend or phenomenon in adolescents. Self-mutilation can be divided into three categories: major, stereotypic, and moderate/superficial. Moderate/superficial self-mutilation is the most common type in adolescents and includes cutting, burning, and carving. School nurses are positioned to identify, to assist, and to educate adolescents who are self-mutilating, as well as those who may be at risk. A crucial intervention by school nurses is referral of students who are self-mutilating, because it is a gateway to treatment. Treatment, which includes therapy and medication, may be a difficult and lengthy process. The adolescent who self-mutilates may find the school environment difficult during treatment. School nurses must become educated about adolescent self-mutilation in order to care for those who engage in this behavior. Prevention of self-mutilation should focus on increasing coping mechanisms, facilitating decision-making strategies, encouraging positive relationships, and cultivating self-esteem.     

Fibular reconstruction for giant cell tumor of the distal radius

The management of giant cell tumors involving the distal radius has always been a difficult problem. After resection to eradicate a primary or recurrent lesion, transplantation of a nonvascularized fibular autograft was used in 12 patients. Of these patients, ten had good to excellent functional results. The procedure can restore a functionally useful wrist.