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PubMed1983

Functional brain tissue transplantation: reversal of lesion-induced rotation by intraventricular substantia nigra and adrenal medulla grafts, with a note on intracranial retinal grafts.

Using a rotational behavior animal model, it has been found that embryonic substantia nigra (SN) can be homologously transplanted to the brain lateral ventricles to reverse the effects of SN lesions. These grafts were found to decrease the lesion-induced rotational behavior that was provoked either by apomorphine or amphetamine. This effect was not duplicated by grafts of other embryonic brain regions. The SN grafts produced a dopaminergic reinnervation of the dorsomedial striatum that appeared to be responsible for the behavioral amelioration. Long-term studies demonstrated that behavioral efficacy and survival continued for at least 6 months to 1 1/2 years. The catecholaminergic "chromaffin" cells of the adrenal medulla possess a remarkable ability to change morphologically and biochemically in response to their environmental hormonal milieu. This plasticity was exploited by transplanting adrenal medulla to the rat brain to reverse the effects of SN lesions. This tissue changed biochemically by producing large amounts of dopamine, and morphologically, by extending coarse fiber processes. Although these grafts appeared to secrete catecholamines, they did not reinnervate the striatum. Rotational behavior was reduced by these grafts, apparently as a consequence of the catecholamine secretion. When adrenal chromaffin tissue was obtained from 1- or 2-year-old donors, however, lesion-induced rotational behavior was not reduced. It is suggested that adrenal chromaffin cell grafts from young donors possess a biochemical plasticity that is the basis for the behavioral effect, but that this plasticity is lost with maturity of the tissue. An important issue for future applications of these procedures is the immunological privilege of the brain lateral ventricles. We found that both embryonic brain tissue and adult adrenal medulla "allografts" from Brown Norway rat donors consistently survived for at least 6 months in the ventricles of Fisher 344-strain rat hosts. These strains differ in major histocompatibility antigens and, as expected, Fisher 344 rats rapidly rejected Brown Norway skin grafts. Skin graft survival times were not influenced by the presence of established brain grafts, nor did brain grafts elicit systemic humoral immunity. Conversely, however, independent elicitation of systemic immunity by skin grafting resulted in the rejection of long-established brain grafts concomitant with rejection of the skin grafts. Rotational behavior in Fisher 344 hosts was reduced by brain grafts from Brown Norway donors; yet, after rotation had been reduced it could be brought back to baseline levels through systemic immunization and associated brain graft rejection.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal Medulla↗
PubMed1980

[Effect of parenteral amino acid administration on the brain function and the serum aminogram of patients with liver cirrhosis].

10 patients with cirrhosis of the liver, 5 with hepatic encephalopathy, were treated by infusion therapy with an amino acid solution adapted to the metabolic conditions seen in hepatic insufficiency. In all cases the amino acid imbalance improved. In 11 episodes of hepatic coma, changes in the pattern of serum amino acids always were accompanied by a marked decrease of elevated ammonia levels and a restitution of clear consciousness. This clinical improvement developed rather rapidly and could be objectivated impressively by psychometric tests.

Adult↗
PubMed1993

Functional brain imaging in late-life depression and dementia.

Studies utilizing advanced scanning technologies suggest that brain imaging may have a role in the differential diagnosis of some common neuropsychiatric disorders. In subjects with dementia of the Alzheimer type (DAT), widespread cortical reductions in glucose metabolism and blood flow have been described, with predominant involvement of the temporal and parietal lobes. The primary sensory areas and subcortical regions are relatively spared. When a "patchy" pattern of reductions in cerebral blood flow and metabolism is associated with clinical dementia, a vascular etiology should be suspected. Major depression in the elderly is associated with reductions in whole brain glucose metabolic rates comparable in magnitude with those described in DAT. Relatively distinctive patterns of flow and metabolism also are seen in frontal-temporal dementia and Parkinson's disease with dementia.

Age Factors↗