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Biomedical subjects

C R Lake

Publications and source records attributed to C R Lake.

187 records · Page 11Linked to original sources
PubMedDate not supplied

The effects of testosterone on plasma and platelet monoamine oxidase (MAO) an plasma dopamine-beta-hydroxylase (DBH) activities in the male rhesus monkey.

Dopamine-beta-hydroxylase (DBH) and monoamine oxidase (MAO) in plasma and platelets were studied in male rhesus monkeys to evaluate the effects of changes in endogenous testosterone on the activity of these enzymes. High plasma testosterone concentrations attained at the end of the mating season were associated with relatively low levels of platelet MAO activity. When testosterone levels fell, platelet MAO increased significantly. Mean differences in platelet MAO activity between a group of castrated and control males were in the direction expected, with the highest MAO activity in the castrated monkeys, but these differences did not attain statistical significance. No significant mating season or castration effects were seen in plasma DBH or MAO enzyme activities. These data support the hypothesis of a link between testosterone and some monoamine systems, and possibly the monoamine-related behaviors linked to testosterone in primates.

Animals↗
PubMedDate not supplied

Plasma noradrenaline and dopamine-beta-hydroxylase during sexual activity.

Plasma noradrenaline (NA) concentrations and the activity of its synthetic enzyme, dopamine-beta-hydroxylase (DBH), were determined during sexual activity in one male subject on three occasions. Blood was obtained through an intravenous catheter by means of a peristaltic pump and an automatic fraction collector. NA was significantly (P less than 0.001) related to stages of sexual arousal and erection quality. Maximal arousal and erection was accompanied by plasma NA concentration 100% to 1200% higher than basal levels. NA levels also increased significantly with upright posture and with emotional stress. DBH activity did not correlate closely with sexual arousal and erection.

Adult↗
PubMedDate not supplied

Psychosis in an adolescent patient with Wilson's disease: effects of chelation therapy.

Wilson's disease is a rare genetic disorder involving the liver and brain, with onset frequently in adolescence. Psychiatric symptoms are often the first manifestation of the disease and can obscure the diagnosis. Chelation therapy can reverse the fatal outcome of untreated patients, so early detection is critically important. This paper describes an adolescent with Wilson's disease who, after initiation of penicillamine therapy, developed florid psychosis that improved as copper levels were decreased and that did not require use of neuroleptic medication.

Adolescent↗
PubMedDate not supplied

Age-dependence of hypertensive-normotensive differences in plasma norepinephrine.

We compared venous plasma norepinephrine (NE) concentrations in 191 resting, supine patients with essential hypertension and 129 normotensive controls. Among normotensives, plasma NE increased significantly with age, but among hypertensives, no age-related increase occurred, due to relatively high NE values among young hypertensives. When patients and controls less than 40 years old were considered, hypertensives showed significantly higher plasma NE than the controls (317 vs 245 pg/ml, t = 3.15, p less than 0.01); but above the age of 40 years, no significant hypertensive-normotensive difference was obtained. These results, predicted by recent literature reviews, help to resolve the persistent controversy about sympathetic neural activity in essential hypertension, since such activity appears to be abnormal mainly in young patients. The data are consistent with increased sympathetic nervous system activity in the early stages of essential hypertension.

Adult↗
PubMedDate not supplied

Elevations in cerebrospinal fluid norepinephrine during unilateral and bilateral cerebellar stimulation in man.

Lumbar cerebrospinal fluid (CSF) norepinephrine concentrations determined by radioenzymatic assay in four epileptic patients were significantly higher during either chronic unilateral or bilateral cerebellar stimulation than those determined after a 7-day period without stimulation. The mean CSF norepinephrine levels noted during these two modes of cerebellar stimulation were not significantly different. The percentage of increase in CSF norepinephrine in one patient receiving 200/sec stimulation was 3 times higher than those noted in the three patients undergoing 10/sec stimulation. These evoked alterations in norepinephrine metabolism may relate to the reported modulation of spasticity and cerebral neuronal excitability during chronic cerebellar stimulation. Lumbar CSF cyclic adenosine monophosphate levels determined by radioimmunoassay were not significantly altered by either mode or frequency of cerebellar stimulation.

Cerebellum↗