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Biomedical subjects

M Waugh

Publications and source records attributed to M Waugh.

26 records · Page 2Linked to original sources

High resolution brain SPECT imaging of marijuana smokers with AD/HD.

Marijuana abuse is common among young Americans and even more common among teenagers and adults with attention deficit/hyperactivity disorder (AD/HD). Many teenagers and young adults believe that marijuana is a safe substance to use despite a number of studies demonstrating cognitive impairment with chronic or heavy usage. Brain single photon emission computer tomography (SPECT) imaging is being used increasingly in psychiatry to study underlying functional brain problems, including AD/HD. SPECT provides information on cerebral blood flow and metabolic function. Brain SPECT studies were performed on 30 heavy marijuana users (who had used on at least a weekly basis for a minimum of one year) with AD/HD from an outpatient psychiatric clinic and 10 AD/HD control group subjects matched for age and sex who had never used drugs. The three-dimensional surface images were used in the analysis of the scans, and were blindly interpreted without knowledge of the clinical data. Decreased perfusion in the prefrontal cortex was the only abnormality seen in the AD/HD control group (80%). In the marijuana group, there was a similar decrease in the perfusion of the prefrontal cortex while performing the same concentration task (83%). However, the marijuana group also demonstrated marked decreased activity in the right and left temporal lobes. The severe and moderate ratings were found in the heaviest users, but not necessarily the longest users. This study demonstrates decreased cerebral perfusion in the temporal lobe regions of the brain on SPECT imaging from chronic marijuana usage.

Adolescent↗

Status dystonicus and Hallervorden-Spatz disease: treatment with intrathecal baclofen and pallidotomy.

Severe dystonia or status dystonicus is a life threatening disorder that develops in patients with both primary and secondary dystonia. We present the case of a 9-year-old boy with Hallervorden-Spatz disease (HVS) who developed status dystonicus, failing to respond to high dose oral therapy with multiple antidystonic agents. High dose intravenous sedating agents combined with endotracheal intubation and mechanical ventilation were required to control the spasms. Alleviation of the spasms was achieved by a combination of temporary intrathecal baclofen infusions and bilateral pallidotomy. Although it could be argued this is a situation where only palliative measures should be used, we believe a relatively aggressive approach was justified. It relieved the intense pain associated with the spasms and allowed the child to be discharged home without the prolonged stay in intensive care, morbidity and mortality, which characterize status dystonicus.

Baclofen↗

Sympathoadrenal and renin-angiotensin systems in the development of two-kidney, one clip renal hypertension in rats.

The relative roles of the sympathetic nervous system and renin-angiotensin system in the development of two-kidney renal hypertension were studied using four groups of rats: Group I = vehicle control; Group II = 6-OH-dopamine (2 weeks prior to renal clipping then weekly throughout the study); Group III = adrenal medullectomy plus vehicle; Group IV = 6-OH-dopamine plus adrenal medullectomy. Six weeks after clipping of a single renal artery, plasma renin activity (PRA) was comparably elevated in all groups. However, mean blood pressure (MBP) of Group II was lower than that of Group I controls (154.7 +/- 6.8 vs 197.3 +/- 6.6 mm Hg respectively). The MBP of Group III (207.0 +/- 5.2 mm Hg) was not different from that of Group I whereas in Group IV (134.2 +/- 18.0 mm Hg) it was markedly lower. All groups of rats were given a single dose of captopril (30 mg/kg p.o.) to inhibit the renin-angiotensin system. Despite differences in starting MBP, captopril caused similar reductions (38-50%) of MBP and increases in PRA in all groups. Similar results were obtained in two-kidney renal hypertensive rats with hypertension of 12 weeks' duration. It is concluded that the sympathetic nervous system does not contribute to the elevated PRA in two-kidney renal hypertensive rats but does contribute significantly to the development of hypertension in this model.

Adrenal Glands↗