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Biomedical subjects

M Collard

Publications and source records attributed to M Collard.

At least 73 records · Page 4Linked to original sources
PubMed1977

A morphological and chemical study of calcification of the choroid plexus.

Human choroid plexus was submitted to low temperature ashing (LTA) in order to isolate the calcification. The ashing residue was then subjected to morphological, chemical and structural studies using technics such as scanning electron microscopy, flame and flameless atomic absorption spectrometry, infrared spectrometry and X-ray diffraction. Morphologically, the calcification consisted of wound-up fibers forming granules with a diameter of 0.05 to 0.15 mm. The concretions were identified as cristalline Ca3(PO4)2 and hydroxylapatite. The content of trace elements was high, but within the limits found in other biological apatites. In some cases, however, the Fe content exceeded these limit values.

Calcinosis↗
PubMed1977

A morphological and chemical study of calcification of the pineal gland.

A general scheme of analysis for the investigation of minute calcification is presented. After low temperature ashing, the samples are subjected to chemical, structural and morphological study, using atomic absorption spectrometry, infrared spectrometry, X-ray diffraction and scanning electron microscopy. Details about the calcification of the human pineal gland are given. The content of trace elements is very high, but within the limits found in other biological apatites. It is concluded that calcification of the pineal is a more general occurence than has been realized.

Brain Diseases↗
PubMed1977

Cerebral vasoreactivity in senile dementia.

A group of clinical senile dementia patients underwent a series of cerebrovascular examinations. Some of them were standard examinations (fundus oculi, electroencephalogram, rheoencephalogram, cerebral angiogram and pneumonencephalogram) while the others were studying regional cerebral blood flow (rCBF) and modification of flow under fonctional tests (hypercapnia, hypocapnia and intravenous injection of 50 mg chl. papaverine) using the 133Xe clearance technique. The senile dementia group (III) was compared with 'normal' old patients group (I) and with patients suffering from sequelae of a previous stroke or from minor mental disorders (group II). Elderly subjects regarded as 'normal' often present alterations in usual vascular examinations but reveal a relative integrity of cerebral autoregulation. Some patients considered irreversibly 'sclerotic' still have a good grey matter flow (r1CBF) with real vasomotor possibilities. In each of the three groups of elderly subjects, there seemed to be a lack of correlation between the clinical symptoms and certain specific vascular examination.

Aged↗
PubMed1977

[The role of the Scanner in traumatic cerebral pathology (author transl)].

The authors describe the tomodensitometric characteristics of various traumatic cerebral lesions: extradural haematoma, subdural haematoma, contusion. In the acute phase, traumatic lesions are characterised by the typical absorption pattern of the bloody effusion and perilesional oedema. In association with these specific densitometric signs there is naturally an alteration in normal cerebral anatomy. The course of traumatic lesions may be followed using the scanner. The signs alter with resorption of the haemorrhage and the regression of oedema, as well as with the secondary development of a focal atrophic process. The advantages of the scanner over oconventional neuroradiology are considerable, not only from a medical and technical standpoint, but also for ethical and medicolegal considerations.

Adolescent↗
PubMed1977

[New possibilities of anatomo-clinical correlation in aphasia using cerebral tomodensitometry (author's transl)].

The authors present a method using cerebral tomodensitometry to establish anatomo-clinical correlations in aphasia. They confirm, in their broad lines, the results of previous studies. They stress the importance of the material that could be studied by this method and define the ideal conditions in which future work should be carried out. (Acta neurol. belg., 1977, 77, 351-362).

Aphasia↗
PubMed1977

[Opsoclonia: oculographic study].

Oculographic study of a case of opsoclonus associated with infectious meningoencephalitis was used to determine the criteria of definition of this abnormal ocular movement, distinguishing it from the other abnormal movements of flutter and dysmetria. The authors first discuss, on the basis of these recordings, the possible relationship between opsoclonus and myoclonia, and then the role of the cerebellum. The disturbances noted in the course of study of saccadian movement lead them to suggest the hypothesis of overall involvement of the saccadian oculomotor system. They stress the value of oculographic recording in better understanding the general mechanisms of saccadian movement and the pathogenesis of the various changes which may be encountered.

Adult↗
PubMed1977

[The use of arteriography in the pharmacological study of a vasodilator substance].

The administration of a vasodilator substance is followed by the development of a higher contrast gradient in a given film in comparison with a reference X-ray carried out in the same subject under comparable technical conditions. Comparative densitometric measurement of the contrast gradient in the two successive arteriographic series, one with and one without the injection, arterial or venous, of a vasodilator substance (Couramine-Rutine) represents a valuable method for the study in man of the action of the substance in a visceral territory. The present study was limited to the kedney (79 cases), ans the territory of the superior mesenteric (46 cases). The absence of any densitometric difference between the two renal series at too low doses of vasodilator substance leads to the supposition of the possibility of a threshold dose of pharmacological activity.

Absorptiometry, Photon↗
PubMed1976

[Usefulness of renal scinitigraphic scanning in the prognosis of acute renal failure (author's transl)].

The authors present their first results concerning the use of renal scintigraphic scanning using hippuran in acute renal failure (A.R.F.). The tubular stages of hippuran, extraction and secretion then excretion correspond to phenomena which are normally apparent within the first 10 minutes following the injection of hippuran, also it seemed interesting to study the changes which occur in A.R.F. 18 hospital in-patients with A.R.F. were studied, 10 of them suffering from tubulointerstitial nephropathy (T.I.N.) 4 with acute glomerulonephritis (A.G.N.), 2 with obstruction of the urinary pathways and 2 with tubular necrosis on underlying chronic renal failure. In the 10 cases of T.I.N. the phenomenon of extraction was evident without any sign of secretion appearing during the 24 minutes of the investigation. No relationship could be found between the scintigram and the rapidity of recovery from A.R.F., but 8/10 recovered satisfactory renal function, the two others died from their disease, the A.R.F. being only secondary. Two of the 4 cases of A.G.N. had normal or slightly lowered extraction and minimal or absent secretion, and they recovered, in the 2 others no image of extraction appeared within 24 mn. and in these 2 cases the course was unfavorable. Finally, the last four had evident extraction and for 3 of them the course was favorable, the death of the fourth being consecutive to the primary disease. It therefore seems that the presence of an extraction phenomenon, whatever the aetiology of the A.R.F., is a parameter which authorizes the prognosis of a favorable course whereas its absence during the 24 mn. of the investigation permits one to envisage an unfavorable course.

Acute Kidney Injury↗
PubMed1976

[Dopamine beta hydroxylase. Value and limits of its study in neurology].

Plasma dopamine-beta-hydroxylase was studied in 96 subjects, 33 of them controls and 63 of them patients (Parkinson's disease, chronic chorea, torsion dystonia, postural tremor and epilepsy). Only the epileptics showed a significant decrease in the average level of dopamine-beta-hydroxylase activity in comparison with the controls. During the cold test, DBH did not vary except in one case. On the other hand, during epileptic attacks, DBH activity underwent considerable fluctuations. Therefore, except in special pathological conditions, such as epileptic attacks, measurement of plasma or serum DBH activity is of limited value for neurological pathology and is not a good indication of the activity of the sympathetic nervous system.

Amantadine↗
PubMed1975

Renal hemodynamic response to l-dopa during acute renal failure in man.

Twelve patients with acute renal failure underwent L.dopa infusion into a renal artery and 133Xenon wash-out recordings before and during the infusion. Urine volume and sodium output were also compared during two 24 hours periods, before and after the procedure. Hemodynamic data were compared with data obtained from a matched group of patients receiving Furosemide (8 patients) in place of L.dopa. Only L.dopa infusion significantly increased outer cortical distribution (p less than 0.005 using paired t-test). No blood flow change could be demonstrated in any component nor did the drug improve urinary excretion or the general course of the disease. Control data shows that reduced cortical distribution is the most consistent feature of acute renal failure, so that L.dopa does partially improve intrarenal hemodynamics in this condition. The failure of the drug to restore kidney function may be explained by the following reasons: a) Inability of the agent to restore a normal wash-out pattern; b) Involvement of non-hemodynamic factors, as suggested by comparing similar wash-out improvements after L.dopa in acute glomerulonephritis and in reversible acute renal failure.

Acute Kidney Injury↗