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Biomedical subjects

E D Bird

Publications and source records attributed to E D Bird.

At least 145 records · Page 8Linked to original sources
PubMed1977

Increased brain dopamine and reduced glutamic acid decarboxylase and choline acetyl transferase activity in schizophrenia and related psychoses.

Dopamine, glutamic acid decarboxylase (G.A.D.) and choline acetyltransferase (C.A.T.) were measured in four regions of post-mortem brains. 41 patients with the hospital diagnosis of schizophrenia (psychotic group) were compared with a control grout normal in the putamen. G.A.D. activity was significantly reduced in the psychotic group, by about 50% in the nucleus accumbens, amygdala and hippocampus, and by about 30% in the putamen. C.A.T. activity was significantly lower in nucleus accumbens from the psychotic group, but normal in other brain regions. From an assessment of case notes, "schizophrenia" was distinguished from "schizophrenia-like psychosis". The biochemical findings for these subgroups were essentially similar, although C.A.T. activity in nucleus accumbens and hippocampus from the schizophrenic group was significantly lower than in controls. It is of brain are associated with schizophrenia and schizophrenia-like psychoses, although whether such neurochemical abnormalities are related to the illness or are a consequence of prolonged treatment with neuroleptic drugs remains unclear.

Adult↗
PubMed1977

Huntington's chorea: selective depletion of activity of angiotensin coverting enzyme in the corpus striatum.

The activity of angiotensin converting enzyme, which transforms the relatively inactive decapeptide angiotensin I to the active octapeptide angiotensin II by removal of an L-histidyl-L-leucine residue, has been assayed in numerous region of the calf brain and of the brains of humans with Huntington's chorea and controls. In calf brain there are pronounced regional variations in enzyme activity, with highest activity in the globus pallidus and area postrema. In human brain, enzyme activity is highest in the corpus striatum, with similar levels in the caudate, putamen, and globus pallidus. Converting enzyme activity is reduced by 83 to 92% in the globus pallidus in Huntington's chorea. The caudate and putamen of choreic patients display 62 to 69% reductions in enzyme activity. Converting enzyme activity in two cerebral cortical regions from choreic brains is not significantly different from control.

Animals↗
PubMed1977

Plasma glucose, non-esterified fatty acids and amino acids in Huntington's chorea.

1. The metabolic responses to an oral glucose tolerance test (100 g) and an intravenous insulin provocation test (0-1 i.u./kg) were studied in nine control subjects and nine patients with Huntington's chorea. 2. Plasma glucose responses to these stimuli were identical in both groups. 3. High fasting concentrations of non-esterified fatty acid (NEFA) were recorded in the choreic patients when compared with control subjects. This difference was maintained under hypoglycaemic conditions. However, during hyperglycaemia the differences in NEFA concentrations between the groups was abolished. 4. Total plasma tryptophan concentrations were equal in the two groups. Free plasma tryptophan, however, was markedly reduced in the choreic group, and this appeared to be a result of a disturbed relationship between free tryptophan and NEFA concentrations. The abnormalities in free tryptophan values were sensitive to plasma glucose concentrations, as hyperglycaemic conditions markedly reduced the differences between the choreic and control group. 5. Patients with Huntington's chorea showed reduced fasting plasma concentrations of leucine, isoleucine and valine.

Amino Acids↗
PubMed1977

Synchronous nyctohemeral rhythms in human blood melatonin and in human post-mortem pineal enzyme.

Serum melatonin was measured by radioimmunoassay at 4-hourly intervals for 24 h in five normal men, and shown to exhibit nyctohemeral variations. The highest concentrations of serum melatonin occurred at 02.00 hours and the lowest concentrations at 14.00 hours. The synthetic enzymes for melatonin, serotonin-N-acetyl transferase (SNAT) and hydroxyindole-O-methyltransferase (HIOMT) were measured in post-mortem pineal organs from thirty-six men and women, and the activity of both enzymes was directly related to the time of death of the subject, resulting in a similar nyctohemeral curve as that observed with serum melatonin. The SNAT and HIOMT enzymes were stable when measured in pineal organs held under the usual post-mortem conditions. The observations indicated a nyctohemeral rhythm in human pineal function and suggests that any clinical interpretation of pineal dysfunction in disease states should take into consideration this normal rhythm.

Acetylserotonin O-Methyltransferase↗
PubMed1977

Neurochemical findings in Huntington's chorea.

Huntington's chorea is a dominantly inherited disorder that usually leads to involuntary movements in the third or fourth decade. On gross pathological examination of the post-mortem brain there is a marked atrophy of the caudate nucleus and putamen. Histological examination reveals cell loss in most regions of the brain, although the hippocampus is usually remarkably free of any abnormalities. Studies to detect a biochemical defect in patients with chorea have been largely unrewarding. Since chorea appears to be the clinical counterpart of Parkinson's disease a number of investigations on dopamine metabolism have been carried out by measuring dopamine in the post-mortem choreic brain, and HVA, a metabolite of dopamine, in the CSF of patients. Most studies have found the dopamine concentrations to be normal or sometimes decreased and the activity of the biosynthetic enzyme for dopamine, tyrosine hydroxylase, is normal. The discovery that the inhibitory neurotransmitter, GABA, and the biosynthetic enzyme GAD are greatly decreased in the post-mortem choreic brain provides some rational explanation for the uncontrolled movements in this disorder. The other significant abnormality found in many, but not all, choreic post-mortem brains has been a decrease in the biosynthetic enzyme for acetylcholine, choline acetyl transferase. The evidence that GABA receptors are intact in choreic brain provides an added stimulus for the development of useful GABA-mimetic drugs. For the ultimate eradication of this distressing disorder, however, a search must continue for the primary defect in order that this can be detected before the onset of symptoms, or hopefully in amniotic fluid.

Acetylcholine↗
PubMed1976

Huntington's chorea. Changes in neurotransmitter receptors in the brain.

Neurotransmitter-receptor binding sites for apparent muscarinic cholinergic, beta-adrenergic, gamma-aminobutyric acid and serotonin receptors were measured in the caudate nucleus and frontal cerebral cortex from post-mortem brains of 16 patients with Huntington's chorea and 16 controls. In addition, the samples were assayed for the gamma-aminobutyric-acid-synthesizing enzyme, glutamic acid decarboxylase, and for the acetylcholine-synthesizing enzyme, choline acetyltransferase. In the caudate nucleus of choreic brain, both enzyme activities were markedly lower, with significant decreases in muscarinic cholinergic and serotonin receptor binding, whereas enzyme activities and receptor binding were unchanged in the cerebral cortex. By contrast, gamma-aminobutyric acid and beta-adrenergic receptor binding were not significantly different in choreic and control caudate nucleus or cortex, suggesting that, despite the loss of gamma-aminobutyric-acid-synthesizing ability in the corpus striatum, gamma-aminobuytric acid mimetic drugs might alleviate the movement disorders in Huntington's chorea.

Alprenolol↗
PubMed1976

Plasma growth hormone concentrations in Huntington's chorea.

1. Growth hormone secretion was assessed in nine control subjects and nine patients with Huntington's chorea. 2. Early-morning fasting plasma samples from patients with Huntington's chorea contained abnormally high concentrations of growth hormone. 3. The suppression of growth hormone after oral glucose in choreic patients, unlike the control subjects, occurred at irregular intervals after the glucose was given and was followed, again at irregular intervals, by an exaggerated rebound phase. 4. The response to intravenous insulin was not markedly abnormal in choreic patients. However, there was a significant increase in the rate of rise of growth hormone concentration in the first half and hour after the insulin injection when compared with control subjects.

Fasting↗