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Biomedical subjects

S M Aquilonius

Publications and source records attributed to S M Aquilonius.

At least 127 records · Page 7Linked to original sources
PubMed1975

Clearance of some quaternary amines from the spinal subarachnoid space.

The spinal subarachnoid space was perfused with artificial cerebrospinal fluid (CSF) from the low lumbar level to the middle thoracic level or to the cisterna magna in anesthetized rabbits. 3-H-choline, 3-H-methyl-atropine or 3-H-decamethonium with carrier in different concentrations was added to the perfusate together with 14-C-inulin, the latter serving as a marker of the dilution of the perfusate by original CSF. Choline was eliminated from the perfusate partly by a saturable mechanism probably by an uptake into the spinal cord. About 15 per cent of the radioactivity of the choline infused was recovered from the spinal cord mainly as phosphorylcholine, betaine, and phospholipids. Amphetamine decreased the elimination of choline from ventriculocisternal perfusates and partly inhibited the uptake of choline in rabbit choroid plexus in vitro. In contrast, amphetamine did not influence the saturable elimination of choline in the lumbothoracic perfusion. Neither methylatropine nor decamethonium was eliminated from the perfusate by a saturable mechanism in the lumbothoracic perfusions. However, in perfusions including the cisterna magna methylatropine was partly eliminated by such a mechanism. The concentration of radioactivity in fourth ventricular choroid plexa suggested this structure to be responsible for the saturable part of the elimination. In conclusion, there is no active removal of quaternary amines in general from spinal CSF like the choroid plexus mediated clearance from ventricular CSF.

Animals↗
PubMed1975

Muscle spindle activity in alternating tremor of Parkinsonism and in clonus.

Single unit activity in spindle afferent nerve fibres from the finger flexors, the anterior tibial muscle, and the calf muscles was recorded intraneurally with tungsten microelectrodes in patients with Parkinsonism with resting tremor and in spastic patients with clonus. During tremor of Parkinsonism, involving the receptor bearing muscles, the Ia afferent fibre discharge patterns were similar to those seen previously in healthy subjects during voluntary fast alternating finger or foot movements: besides the stretch discharges occurring during the relaxation phases, discharges also occurred during the contraction phases. Such contraction discharges, presumed to originate from intrafusal muscle fibre contractions, were not seen in the spastic patients during clonus. During the clonic oscillations each afferent stretch discharge was regularly followed by a stretch reflex contraction which on its falling phase elicited a new volley of impulses in the Ia afferent fibres. The findings are considered to support the notion that, like the contractions in normal voluntary alternating movements, the contractions in tremor of Parkinsonism are organized according to the principle of alpha-gamma coactivation, whereas the contractions in clonus are stretch reflexes causing pure alpha contractions.

Adult↗
PubMed1975

Regional distribution of choline acetyltransferase in the human brain: changes in Huntington's chorea.

A stereotaxic method of tissue sampling has been developed permitting detailed studies of the distribution of choline acetyltransferase (CAT) in brains from controls and from patients suffering from Huntington's chorea. The characteristic pattern of CAT distribution within extra-pyramidal structures is described. In Huntington's chorea, CAT is unevenly reduced in several brain regions particularly in the rostromedial part of the caudate nucleus. The results indicate a preferential degeneration of neostriatal cholinergic neurones in Huntington's chorea.

Acetyltransferases↗
PubMed1972

Cerebrospinal fluid choline in extrapyramidal disorders.

Cerebrospinal fluid from patients with Parkinson's disease and Huntington's chorea has been investigated with regard to the concentration of choline. In Parkinson's disease the choline concentration of lumbar spinal fluid was not different from that of a control group, nor was it related to medication, duration of illness, or severity of symptoms. A comparison between choline in ventricular cerebrospinal fluid from patients with Parkinson's disease and with intention tremor showed no significant differences. Patients with Huntington's chorea had a lower concentration of choline in lumbar spinal fluid as compared with a control group. The results are discussed in relation to the possible sources of cerebrospinal fluid choline.

Acetylcholine↗