Biomedical subjects

A Edman

Publications and source records attributed to A Edman.

22 records · Page 2Linked to original sources

PubMed1983

Intracellular ion control in lobster stretch receptor neurone.

The control of intracellular ion concentrations by means of passive and active transmembrane ion transports was investigated in the lobster stretch neurone using electrophysiological and pharmacological techniques in combination with recording with ion-sensitive microelectrodes. In resting conditions [Na+]i, [K+]i, and [Cl-]i were, in both slowly and rapidly adapting cells, found to be in the order of 20, 155, and 50 mM, respectively. In the slowly adapting cell impulse firing at stationary frequencies of 7-10 Hz caused an increase in [Na+]i and a decrease in [K+]i of 20-30 mM; [Cl-]i was only little affected, the rise in [Na+]i led to an enhanced Na-K pump activity noticeable as an increase in pump current production. In stationary conditions the quotient between pump current and Na+ influx increments was about 0.3, which is compatible with 3:2 Na-K pumping ratio in the present preparation. From measurements of the pump current activation during stationary firing at maximum tolerable frequencies an estimate was made of the cell's maximum pump current production. The measurements were used in the formulation of a mathematical model of the intracellular ion control in which expressions of active and passive transmembrane ion transports are incorporated into the continuity equation for the ion fluxes involved.

4-Aminopyridine↗

PubMedDate not supplied

Longitudinal EEG findings in dementia related to the parietal brain syndrome and the degree of dementia.

EEG slow-wave activity was correlated with the regional brain syndrome profile in 74 patients with dementia. The EEGs were visually assessed using a semiquantitative rating scale. The intensities of four regional brain syndromes (parietal, frontal, subcortical, global) and the degree of dementia were rated. The patients were examined twice with a 1-year interval. A significant relationship was found between the increase in EEG slow-wave activity and the increase in intensity of the parietal brain syndrome. A somewhat lower significance was found for the relation between increase in slow-wave activity and increase in dementia degree. The results suggest that the EEG deterioration in dementia mainly reflects the gradual decline of parietal brain function.

Aged↗

PubMedDate not supplied

The cerebrospinal fluid levels of tau, growth-associated protein-43 and soluble amyloid precursor protein correlate in Alzheimer's disease, reflecting a common pathophysiological process.

Cerebrospinal fluid (CSF) levels of tau (total tau), growth-associated protein-43 (GAP-43), soluble amyloid precursor protein (sAPP; i.e. total sAPP), and beta-amyloid(42) (Abeta(42)) were studied in patients with frontotemporal dementia (FTD; n = 14), Alzheimer's disease (AD; n = 47) and vascular dementia (VAD; n = 16), and in age-matched controls (n = 12). CSF-tau was increased in AD compared to controls and FTD (p < 0.001 for both). CSF-GAP-43 was increased in AD compared to controls (p < 0.05), and both CSF-GAP-43 and CSF-sAPP were increased in AD compared to FTD (p < 0.01). Positive and highly significant correlations were found between CSF-tau and CSF-GAP-43 in all groups and between CSF-tau, CSF-GAP-43 and CSF-sAPP in AD. The correlations found may reflect a common pathophysiologic process such as axonal degeneration.

Aged↗

PubMedDate not supplied

EEG findings in dementia are related to the parietal lobe syndrome.

EEG indicators were correlated with clinical items in 174 patients with dementia diagnoses based on the DSM-III-R criteria. The patients' clinical symptomatologies were presented as regional brain syndromes, i.e. parietal lobe, frontal lobe, subcortical and global (nonregional) syndromes. The EEGs were abnormal in 87% of the cases. The typical abnormalities consisted of diffusely distributed slow wave activity. A significant correlation was found between the degree of slow wave abnormality and the degree of dementia. The results of the statistical analysis also suggest that EEG slow wave activity in dementia primarily reflects parietal lobe dysfunction. No association seems to exist between EEG slow wave activity and frontal lobe dysfunction.

Aged↗