Relation between temperature and processes of spontaneous quantum and non-quantum mediator release from motor nerve endings of the mouse

The spontaneous quantal and nonquantal acetylcholine release was investigated at the temperature range from 10 to 35 degrees C in white mouse semidiaphragm. The quantal release was evaluated by calculation of miniature end-plate potentials frequency, while the nonquantal one--from the H-effect value. The spontaneous quantal release increased exponentially with the temperature growth. The temperature dependence of the nonquantal release showed two relative maxima: at 20 degrees and 35 degrees C. At 10 degrees C the nonquantal release was absent. The value of calculated effective energy of activation of the quantal release was 57.0 kJ/mol in the investigated temperature range. The effective energy of activation for the nonquantal release process in intervals 15-20 degrees C and 25-35 degrees C was 45.5 and 38.2 kJ/mol, relatively. It is suggested that the nonquantal release is rather due to active transport processes than to simple diffusion of acetylcholine molecules.     

Factors relating to the sensory acuity of limbs with peripheral vascular insufficiency

We examined several possible causes for the high incidence of poor sensory acuity in the limbs of 176 patients with moderate to severe peripheral vascular insufficiency. We investigated the relationships of diabetes, alcoholism, and smoking, as well as the severity of peripheral vascular disease, to the integrity of basic sensory modalities such as two-point discrimination and perception of light touch. The presence or absence of diabetes exerted the strongest effect on peripheral sensation. In patients who did not have diabetes, sensation in the limbs was most strongly affected by whether the patient was an alcoholic. Smoking did not have a significant effect on limb sensation. Among nondiabetic, nonalcoholic patients, there was a weak residual effect related to the severity of the peripheral vascular insufficiency. Even among these patients, however, systemic factors predominated in determining the loss of sensation. We also examined the extent to which loss of sensation might be related to the development of ulcers. Among patients who were not diabetic, there was a highly significant relationship between loss of sensation and the presence of limb ulceration. Surprisingly, however, there was no discernable relationship between the presence of ulcers in diabetic patients and the degree of loss of peripheral sensation. This result suggests that a large percentage of ulcers seen in diabetic patients are not of neurogenic origin.     

Using sobriety tests to increase awareness of alcohol impairment

There is a need to investigate methods by which drinkers canbe made aware of their level of alcohol impairment prior todriving. In the current research, 195 students at various bloodalcohol concentration (BAC) levels participated in an evaluationof three simple sobriety tests: a ruler drop/reaction time task,a balance test and a verbal task. Although self-reported measuresof impairment were the best predictors of BAC, both the rulerdrop and body balance tests accounted for significant portionsof BAC variance. These tasks were also perceived by the studentsas reflecting substantial driving ability. Unfortunately, asBAC increased, poor test performance was less likely to resultin a decision not to drive. These results are discussed in termsof the need to continue studying ways to educate drinkers abouttheir level of alcohol impairment so that they can make informeddrinking/driving decisions.     

Carnitine deficiency associated with ornithine transcarbamylase deficiency

An infant with X-linked recessive ornithine transcarbamylase deficiency is described who also had severe deficiency of plasma and liver carnitine during normoammonemic periods. Treatment with L-carnitine (100 mg/kg/day) for 12 months decreased the frequency of hospitalizations for hyperammonemia, although it did not alter his neurologic status. This report demonstrates that persistent carnitine deficiency may be present in patients with ornithine transcarbamylase deficiency even when plasma ammonia is normal. Carnitine evaluation and supplementation may be important in the treatment of patients with this metabolic disorder.