ABSTRACT
Zinc has recently been shown to alleviate inflammatory hyperalgesia. In the present study, we showed that intrathecal, intraplantar or systemic injection of zinc chloride significantly relieved thermal hyperalgesia in rats with sciatic nerve injury. Alleviation of thermal hyperalgesia was dose dependent in each case, although higher doses were required for i.p. injections (ED50 = 13.6 nmole) than for intrathecal (ED50 = 0.05 nmole) or intraplantar injections (ED50 = 0.3 nmole). Neither intrathecal nor intraplantar zinc chloride influenced thermal nociception in normal rats without nerve injury. The results provide the first evidence that zinc alleviates neuropathic hyperalgesia.
Subject(s)
Hot Temperature , Hyperalgesia/drug therapy , Neuralgia/drug therapy , Sciatic Nerve/injuries , Zinc/therapeutic use , Animals , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Foot , Hyperalgesia/etiology , Hyperalgesia/metabolism , Injections, Intradermal , Injections, Intraperitoneal , Injections, Spinal , Male , Nerve Growth Factors/biosynthesis , Neuralgia/etiology , Neuralgia/metabolism , Rats , Rats, WistarABSTRACT
We report a series of 28 pediatric carbon monoxide exposures. Sixteen patients (57%) were judged to have potentially toxic carboxyhemeglobin (COHb) levels (greater than 15%). In this group the range of COHb blood levels was 16.7% to 44.0% (mean = 26.5%). An unusually high incidence of syncope (56.3%, 9/16) and lethargy (68.7%, 11/16) was observed. Every patient with a COHb level greater than or equal to 24% experienced syncope; a marked departure from published adult values. Lethargy was reported at a mean COHb concentration of 25.9%. All patients with levels over 25% COHb, neurologic findings, acidosis, or syncope were considered candidates for hyperbaric oxygen therapy (HBOT). No morbidity from HBOT was encountered. Eighty-nine percent (25/28) of the patients are reportedly doing well, with no late sequelae identified. Delayed neurologic sequelae in three patients include chronic headaches, memory difficulties, or decline in school performance.
Subject(s)
Carbon Monoxide Poisoning/blood , Adolescent , Carbon Monoxide/toxicity , Carbon Monoxide Poisoning/physiopathology , Carbon Monoxide Poisoning/therapy , Carboxyhemoglobin/analysis , Child , Child, Preschool , Female , Humans , Hyperbaric Oxygenation , Infant , MaleABSTRACT
Cumulative dose-response curves were constructed in man for tubocurarine, pancuronium, gallamine and alcuronium from data obtained during barbiturate-narcotic-nitrous oxide anaesthesia. Fifty-six adult patients received one of these drugs, administered by constant-rate infusion, a technique enabling response levels and results pooled to derive a composite dose-response curve for each drug. Using the mechanical twitch response, the ED50 for each neuromuscular blocking drug was: tubocurarine 0.236 mg kg-1, pancuronium 0.048 mg kg-1, gallamine 1.3 mg kg-1 and alcuronium 0.161 mg kg-1. The slopes of the composite curves for pancuronium and alcuronium were significantly steeper than those for tubocurarine and gallamine. In the alcuronium studies the simultaneous compound electromyogram was recorded, and usually this was more depressed than the mechanical twitch response, giving an ED50 of 0.135 mg kg-1.