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Biomedical subjects

J G Young

Publications and source records attributed to J G Young.

At least 37 records · Page 2Linked to original sources
PubMed1987

L-dihydroxyphenylalanine-induced asymmetric changes in striatal uric acid peak: determination by in vivo electrochemical detection in rats with unilateral nigrostriatal lesions.

Rats were unilaterally lesioned with 6-hydroxydopamine to destroy the nigrostriatal pathway. Following injection with 25 mg/kg L-dopa, circling behavior away from the lesioned side was monitored. Concurrently, in vivo electrochemical detection was used to compare changes in striatal extracellular levels of ascorbic acid (Peak 1) and uric acid (Peak 2) on the lesioned and unlesioned sides. Peak 1 changes did not differ, but Peak 2 changed asymmetrically on the two sides. The difference in the changes in Peak 2 was highly correlated with the circling behavior, with the greater increase on the lesioned side.

Animals↗
PubMed1987

Whole blood serotonin in autistic and normal subjects.

Whole blood serotonin and tryptophan were measured in 87 normal subjects and in 40 autistic subjects. Whole blood serotonin concentrations (mean +/- SE) were significantly higher in drug-free (N = 21) autistics (205 +/- 16 ng/ml) than in normals (136 +/- 5.4 ng/ml). The Gaussian distribution of serotonin levels in the unmedicated autistic group suggests the elevation was not due to a subgroup of autistic subjects. Autistics medicated with anticonvulsants or neuroleptics had significantly lower serotonin levels than did drug-free autistic subjects. Whole blood tryptophan levels and platelet counts were similar in the autistic and normal groups. The possible causes of the hyperserotonemia of autism are discussed.

Adolescent↗
PubMed1984

Dopaminergic but not noradrenergic mediation of hyperactivity and performance deficits in the developing rat pup.

The relative contribution of dopamine (DA) and norepinephrine (NE) in behavioral arousal was examined in developing rat pups using intracisternal 6-hydroxydopamine (6-OHDA) either alone or following pretreatment with desmethylimipramine (DMI). Such treatments were designed to examine the effects of preferential reduction of DA (DA depletion), NE (NE depletion), or both catecholamines (CA depletion) in the development of motor activity and escape performance. General motor activity increased with age and, over all ages, DA-depleted pups tended to exhibit greater activity. This was most apparent at 15 days of age, where DA-depleted pups were significantly more active than controls, NE-depleted, or CA-depleted pups. DA-depleted pups failed to exhibit the steep decline in activity over time (habituation of activity) demonstrated by the control and NE-depleted pups, while pups depleted of both CA fell into an intermediate position in habituation. Escape latency in a T-maze at 20 days and shuttle box at 26 days of age indicated comparable performance to controls for NE-depleted pups, while those animals in DA-depleted and CA-depleted groups appeared unable to perform the task. Brain CA concentrations (determined by a radioenzymatic assay) indicated preferential reduction of DA in the DA-depleted group to concentrations 25% of controls, reduction of NE to 62% of controls in the NE-depleted group, and reductions of DA to 42% and NE to 60% in the CA-depleted group. These results suggest that preferential reduction of brain DA in the developing rat pup increases motor activity and impairs habituation of activity during the stage of behavioral arousal in week 3 of postnatal life.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1984

The effect of ultra-violet and visible radiation on CaSO4:Dy in Teflon discs used for personnel gamma-radiation monitoring.

The influence of ultra-violet and visible radiation (UV/VIS) on the read-out obtained from the main dosimetry peak of CaSO4:Dy in Teflon discs exposed to the gamma-radiation levels measured by a personnel-monitoring service has been studied as a function of wavelength, irradiance and radiant exposure. The results have been explained by the net effect of three separate factors, namely (i) an inherent response, (ii) a phototransfer and (iii) an optical bleaching. The response obtained from unirradiated discs illuminated with fluorescent room lighting became saturated after 16 hrs at a value corresponding to 0.33 microC kg-1 whilst gamma-irradiated discs faded to 90% of their initial exposure for the same illumination period.

Calcium Sulfate↗
PubMed1984

CSF neurochemistry of women with anorexia nervosa and normal women.

CSF tyrosine, tryptophan, 5-hydroxyindoleacetic acid, 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA), gamma-aminobutyric acid, choline, and calcium were compared in 33 anorexic and 14 normal women. The only significant difference between groups was a lower tyrosine level in the anorexic patients; their MHPG level was nonsignificantly higher. No significant group differences in body weight or depressive subgroup were found. HVA levels were positively related to body weight, and choline was negatively correlated with anorexia severity. The role of tyrosine requires further research, but these findings do suggest that HVA and choline increase with some recovery measures and MHPG is increased with this illness.

Adolescent↗
PubMed1984

CSF neurochemistry in depressed, manic, and schizophrenic patients compared with that of normal controls.

A total of 114 subjects (41 depressed, 20 schizophrenic, 15 manic, and 38 normal controls) underwent lumbar puncture and their CSF was analyzed for levels of tyrosine, tryptophan, homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), 3-methoxy-4-hydroxyphenylglycol (MHPG), choline, gamma-aminobutyric acid (GABA), and calcium. Results showed that depressed patients, particularly those over 40 years of age, had lower levels of GABA than did controls, and that their level of HVA increased with age, while controls' decreased. Schizophrenic subjects tended to have higher levels of 5-HIAA and manic subjects tended to have higher levels of HVA and MHPG. Age-associated changes were found in HVA, 5-HIAA, MHPG, GABA, and choline concentrations.

Adolescent↗
PubMed1984

Poor outcome and low platelet MAO activity in chronic schizophrenia.

Platelet monoamine oxidase (MAO) activity was significantly lower among 21 chronic schizophrenic patients, 19 of whom were receiving stable doses of antipsychotic medication, than among 16 control subjects. Poor ego functioning and poor outcome were significantly correlated with low MAO activity; current dose of major tranquilizer was negatively but not significantly correlated. The degree of psychopathology, rather than presence or absence of specific symptom constellations, was the significant characteristic of patients with low enzyme levels. This finding is in accordance with those of earlier studies of schizophrenic patients as well as with recent findings in nonschizophrenic samples.

Adult↗
PubMed1982

Determination of indoles in human and rat pineal.

Tryptophan, serotonin, N-acetylserotonin, melatonin, 5-hydroxyindoleacetic acid and 5-hydroxytryptophol have been determined in rat and human pineal glands. The compounds were measured by directly injecting centrifuged tissue homogenates into a liquid chromatographic-fluorometric system. Normal ranges are reported for these compounds and upper limits established for several other indoles.

Animals↗
PubMed1982

Clinical neurochemistry of autism and associated disorders.

Advances in information concerning brain function in animals and advances in analytical neurochemical methods for determining extremely low levels of compounds in physiological fluids have opened great opportunities for clinical neurochemical studies of autism. Nevertheless, the behavioral deficits in autistic individuals are major obstacles to clarification of the relations between symptoms and biochemical dysfunction in the brain. The fundamental preclinical and clinical studies of serotonin, dopamine, and norepinephrine metabolism related to infantile autism are reviewed, and new studies are suggested as examples of the productive strategies that will illuminate features of the autistic syndrome in the next decade.

Amines↗
PubMed1982

Tissue to air ratios for open-cut uranium mine employees: a simulation using circular plane sources.

Tissue to air ratios of absorbed dose have been measured for certain organs in an Alderson Rando radiotherapy phantom irradiated by simulated circular plane sources of degraded gamma rays from radium-226. The absorbed dose measurements were performed using thermoluminescent dosemeters. Factors were determined which relate the absorbed dose received by the organ, of interest to (i) the absorbed dose in air at the height of the organ, (ii) the absorbed dose measured by a personal monitor worn at the chest and waist, and (iii) the absorbed dose in air at 1 m above the source. Effective dose equivalents have been calculated using the above factors in conjunction with ICRP 26 weighting factors. The results indicate that a good estimate of the effective dose equivalent can be obtained irrespective of the wearing position of the personal monitor on the trunk.

Air Pollution, Radioactive↗
PubMed1982

Assessment of brain function in clinical pediatric research: behavioral and biological strategies.

Psychobiological research in child psychiatry requires rigorous assessment of behavior and multiple perspectives on brain function through neurochemical, neuroendocrine, psychophysiological, and other advanced methods. The serious neuropsychiatric disorders of childhood, such as autism, attention deficit disorder, and language disorders, can be studied in complementary clinical protocols aimed at explicating patterns of behavioral and metabolic dysfunction which characterize various clinical syndromes. Clinical research with children raises sensitive ethical issues; the ethical problems can be addressed when children and families are active collaborators with the investigators and a long-term relationship is established. In this setting, participation in research can facilitate better treatment for a child. The use of novel biological strategies, such as pharmacological challenge tests, permits evaluation of the relation of specific neuronal systems to behavioral dimensions in clinical disorders. The development of a new treatment for Tourette's syndrome illustrates the integration of basic and clinical research methods.

Catecholamines↗
PubMed1982

Thyroid function in developmental disorders.

The relationships between catecholamines and thyroid state are considered from clinical and molecular perspectives. The effects of thyroid hormone on adrenergic systems are mediated by altered receptor and post-receptor function. Clinical symptoms of major childhood neuropsychiatric disorders, as well as related biological measures, may be influenced by thyroid hormone regulation.

Brain↗