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Biomedical subjects

G M Anderson

Publications and source records attributed to G M Anderson.

At least 163 records · Page 9Linked to original sources
PubMed1989

Neurochemical study of dopamine functioning in autistic and normal subjects.

Plasma prolactin (PRL) and homovanillic acid (HVA) levels, and urinary HVA and dopamine (DA) excretion, were measured in groups of unmedicated autistics, medicated autistics, and normal controls. No significant differences were found between unmedicated autistics and normal controls in plasma PRL and HVA levels. Excretion rates of urinary HVA and DA were also similar in the unmedicated autistic and normal subjects. Plasma PRL and HVA, as well as urinary HVA excretion, were significantly increased in the autistics on neuroleptic medication compared to the unmedicated autistics. A significant correlation (r = 0.46, p = less than 0.05) was observed between dose of neuroleptics and plasma PRL values; the correlation (r = 0.42) between neuroleptic dose and plasma HVA levels approached significance (p = 0.06). In contrast, no differences were observed in urinary DA excretion between medicated and unmedicated autistics. In general, the findings indicate that peripheral indices of dopamine functioning are normal in autistic subjects.

Adolescent↗
PubMed1989

Regionalization of coronary artery bypass surgery. Effects on access.

Coronary artery bypass surgery (CABS) has been regionalized in the province of Ontario since the introduction of the procedure in the 1970s. The authors examined the effect of regionalization on the age-adjusted surgery rates in the 38 counties of southern Ontario and found that county surgical rates were not related to whether the county had a referral center, bordered on a county with a referral center, or did not border on such a county (R2 = 0.019, P = 0.712). In addition, surgical rates were not related to the distance in miles to the nearest referral center (R2 = 0.019, P = 0.440). The authors also examined the relationship between the referral center providing care to the county and surgical rates and found a significant relationship between rates of surgery and referral center regardless of whether a strict rule (R2 = 0.741, P less than 0.0001), a majority rule (R2 = 0.514, P less than 0.0001), or a plurality rule (R2 = 0.497, P less than 0.0001) was used to assign counties to referral centers. The authors conclude that CABS rates are more related to the center serving the county than to the distance of the county from a referral center and discuss this finding in relation to access to care and its impact on costs and quality.

Coronary Artery Bypass↗
PubMed1989

MR imaging: vascular anatomy of the abdomen.

In support of the thesis that MRI may replace more invasive angiography in some applications, a total of 28 MR sections are presented to illustrate the vascular anatomy of the abdomen in coronal, transverse and sagittal planes. More than 20 vessels are identified ranging in size from the aorta to the left inferior adrenal vein and the spermatic veins. There is no anatomic continuity in sections made in the coronal and transverse planes; sequential sections of a single patient are presented in sagittal and parasagittal planes, however. The polarity of the images is reversed for ease of comparison with angiograms.

Abdomen↗
PubMed1989

The long good-bye: the great transformation of the British Columbia hospital system.

Much is made of the "threat" an aging population poses to North American health care systems. In this article, we present hospital utilization data from British Columbia over the period 1969-1985, which reinforce our earlier (Barer, Evans, Hertzman, et al. 1987) conclusion: it is not aging per se that poses the threat; rather, it is what we are choosing (through our health care system) to do to and with our elderly. In 1969, British Columbia hospital patients over 65 years of age and staying longer than 60 days accounted for 12.5 percent of all days; by 1985/86, they were accounting for 39 percent. Furthermore, in 1985/86, 1 patient in 200 was using one-quarter of all patient days and dying at the end of the process, and 2 patients in 100 (who stayed over 60 days whether discharged alive or dead) were accounting for almost one-half of all days.

Adolescent↗
PubMed1988

High-performance liquid chromatographic analysis of neurotransmitter amino acids in brain.

Rapid and selective determination of neurotransmitter amino acids in rat and human brain is accomplished by pre-column derivatization with o-phthaldehyde-3-mercaptopropionic acid, reversed-phase high-performance liquid chromatographic separation, and fluorimetric detection. Aspartate, taurine, glutamate, and glycine are determined in less than 12 min with intra- and inter-assay precisions of 2.1-9.5% and 4.2-9.2%, respectively. gamma-Aminobutyric acid is determined in less than 8 min with intra- and inter-assay precisions of 1.6 and 11.7%, respectively. Both assays utilize internal standards and require a minimum of sample preparation.

Amino Acids↗
PubMed1988

Cerebrospinal fluid indoleacetic acid in autistic subjects.

Cerebrospinal fluid (CSF) levels of the tryptamine metabolite, indoleacetic acid (IAA), have been measured in groups of autistic and control subjects. No significant difference was seen in group mean (+/- SEM) levels of CSF IAA (autistics 5.53 +/- 0.47 ng/ml, N = 10). The finding indicates that central metabolism of the behaviorally active trace amine tryptamine is probably normal in autism.

Adolescent↗
PubMed1988

Plasma MHPG: within- and across-day stability in children and adults with Tourette's syndrome.

Within- and across-day stability of unconjugated plasma 3-methoxy-4-hydroxyphenethyleneglycol (pMHPG, the major metabolite of norepinephrine) levels were assessed in several subgroups of 47 primarily child and adolescent subjects with Tourette's syndrome (TS). Mean morning pMHPG levels remained stable over a 20-min period from 8:30 to 8:50 AM at 3.5 +/- 0.8 ng/ml. However, the mean intraindividual fluctuation in pMHPG levels over 20 min was +/- 12%. Mean pMHPG levels remained stable in the morning from 8:00-8:30 AM to noon. However, an 11% decrease (p less than 0.01) in mean pMHPG levels was observed in the afternoon between noon and 3:00-4:00 PM. Monitored on consecutive days, mean morning pMHPG levels fell 12% (p less than 0.002). The afternoon and across-day falls in pMHPG levels observed in this study of primarily children and adolescents with TS have not been observed in studies of adult control subjects. The results suggest that the design of research protocols involving children and adolescents that use pMHPG should take into consideration the effects of time, both within- and across-day, in pMHPG levels.

Adolescent↗
PubMed1988

Elevated CSF dynorphin A [1-8] in Tourette's syndrome.

A recent neuropathological study has reported decreased levels of dynorphin A immunoreactivity in striato-pallidal fibers in the brain of a patient with severe Gilles de la Tourette's syndrome (TS). This observation, taken with the neuroanatomic distribution of dynorphin and its broad range of motor and behavioral effects, has led to speculation concerning its role in the pathobiology of TS. We report on the presence of elevated concentrations of dynorphin A [1-8] in the CSF of 7 TS patients, aged 20 to 45 years. The increase in CSF dynorphin was found to be associated with the severity of the obsessive compulsive symptoms but not with tic severity in these patients. Although CSF studies lack the precision necessary to address questions of selective involvement of neuronal system in specific CNS locations, these findings suggest that endogenous opioids are involved in the pathobiology of TS and related disorders. Tourette's syndrome (TS) is a chronic neuropsychiatric disorder of childhood onset that is characterized by multiple motor and phonic tics that wax and wane in severity and an array of behavioral problems including some forms of obsessive compulsive disorder (OCD) (1). Once thought to be a rare condition, the prevalence of TS is now estimated to be one case per 1,000 boys and one case per 10,000 girls, and milder variants of the syndrome are likely to occur in a sizeable percentage of the population (2). Although the etiology of TS remains unknown, the vertical transmission of TS within families follows a pattern consistent with an autosomal dominant form of inheritance (3,4). Neurobiologic and pharmacological data have implicated central monoaminergic and neuropeptidergic systems in the pathophysiology of TS, and basal ganglia structures remain the prime candidates as the neuroanatomical origin for TS and related conditions (1). Endogenous opioids, including dynorphin and met-enkephalin are concentrated in structures of the basal ganglia (5), are known to interact with central dopaminergic neurons (6, 7), and may play an important role in the control of motor functions (8). Post-mortem brain studies have directly implicated opioids in the pathophysiology of Parkinson's disease (9), Huntington's disease (10), and most recently in TS (11). The neuropathological study of Haber et al. (11) reported decreased levels of dynorphin A [1-17] immunoreactivity in striatal fibers projecting to the globus pallidus in the brain of a patient with severe TS. This ovservation, taken with the neuroanatomic distribution of dynorphin and its broad range of motor and behavioral effects, has led to speculation concerning its role in the pathobiology of TS.(ABSTRACT TRUNCATED AT 400 WORDS)

Dynorphins↗
PubMed1988

The ontogeny of 3,4-dihydroxyphenylacetic acid in human cerebrospinal fluid.

Measurement of cerebrospinal fluid (CSF) levels of the minor dopamine metabolite 3,4-dihydroxyphenylacetic acid in neonates and children indicates that a rapid decline (approximately 90%) occurs in the first 2 years of life. The much less rapid ontogenetic decline seen for the predominant dopamine metabolite, homovanillic acid (HVA), indicates that differing factors affect CSF levels of the two acid metabolites. Further study is required to determine which compound more closely reflects ontogenetic changes in dopamine functioning.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Monitoring the diffusion of a technology: coronary artery bypass surgery in Ontario.

Technology assessment involves not only examining technologies before they are released but also their diffusion into practice once they have been released. In this study we show how basic analysis of a large administrative data set, combined with a review of evidence on effectiveness, can be used as the first step in technology assessment. We analyze the use of coronary artery bypass surgery (CABS) in the province of Ontario, Canada. The annual number of procedures increased 52 per cent over a seven-year period between 1979 and 1985. Large increases in CABS rates in the over-65 population accounted for more than half of this increase in procedures. Increased rates of surgery in the over-65 population are unlikely to be caused by increased prevalence of coronary artery disease and may be the result of a change in clinical attitude toward the use of CABS. This change is discussed in the context of the evidence on the effectiveness and cost-effectiveness of CABS. We conclude that there is a need to carefully monitor and evaluate the use of technologies especially in the elderly.

Adult↗
PubMed1987

Steady-state model for plasma free and platelet serotonin in man.

A steady-state physiological flow model has been developed for predicting plasma free serotonin (5-HT), and platelet 5-HT, concentrations in man. The basic assumptions of the model are that 5-HT is produced in the wall of the intestine, enters the portal circulation at a constant rate, and is cleared by the lung, liver, kidney, and capillary bed. When a priori best estimates of the 5-HT production rate and organ extraction efficiencies were substituted into formulae describing the model, a predicted value for plasma free 5-HT of 304 pg/ml was obtained, in good agreement with a previously observed mean (+/- SE) of 387 +/- 84 pg/ml. The effects of varying production rate and extraction efficiency parameters on predicted levels of plasma free 5-HT are examined. The practical implications of the model and its possible utility in elucidating the causes of altered plasma free or platelet 5-HT seen in certain conditions are discussed.

Blood Platelets↗
PubMed1987

Serotonin in cisternal cerebrospinal fluid of the rat: measurement and use as an index of functionally active serotonin.

A simple, selective reverse-phase HPLC-fluorometric method is described for the determination of serotonin (5HT) in cisternal CSF of the rat. The mean (+/- SE) value of CSF 5HT observed in control adult rats was 457 +/- 83 pg/ml (N = 16). In an attempt to validate the measure as an index of extracellular, or functionally active, 5HT, groups of animals were treated with fenfluramine, amitriptyline, pargyline, pargyline plus tryptophan, and 5-hydroxytryptophan plus carbidopa. In all cases CSF 5HT appeared to reflect well the presumed effects of the agents on extracellular levels of 5HT. CSF 5HT was superior in this regard to brain 5HT, brain 5HIAA, or CSF 5HIAA levels. The measurement of cisternal CSF 5HT would appear to offer a convenient index of functionally active 5HT.

Amitriptyline↗
PubMed1987

Plasma-free homovanillic acid: within- and across-day stability in children and adults with Tourette's syndrome.

Within- and across-day stability of plasma-free homovanillic acid (pHVA) was assessed in children and adults with Tourette's syndrome. A diurnal fall in pHVA was observed in 13 of 15 subjects. There was a small but significant (p less than .0001) decrease (8%) in mean morning pHVA levels obtained just 20 minutes apart (8:30 A.M. and 8:50 A.M.). A substantial and significant (p less than .001) mean decrease in pHVA (25%) was observed when samples obtained between 8:00 and 8:30 A.M. were compared with samples obtained at 12:00 noon. Changes in pHVA levels observed during the afternoon (between 12:00 noon and 4:00 P.M.) were small, nondirectional, and nonsignificant. Repeated measurement of morning pHVA in the same individual after 24 or more hours revealed marked increases or decreases in many individuals, suggesting that morning pHVA is not a stable measure. The results of this and previous studies suggest that pHVA obtained at 12:00 noon or later in the day may be a more reliable measure of centrally produced HVA. Further studies are needed regarding the stability of pHVA over time.

Adolescent↗