PubMed Health⌕ Search

Biomedical subjects

F Arnaud

Publications and source records attributed to F Arnaud.

15 recordsLinked to original sources
PubMed1992

Effect of a dopaminergic agonist, piribedil (Trivastal 50 mg LP), on visual and spatial integration in elderly subjects.

Dopamine acts as a neuromodulator in the retina. Dopaminergic deficiency of any origin, as observed in elderly subjects, is associated with altered visual performances, and more specifically with altered perception of contrasts. The goal of this study was to compare contrast vision in elderly subjects and young subjects (first phase, n = 20), then to compare this function in elderly subjects before and after 3 months of treatment with a dopaminergic agonist, piribedil (Trivastal 50 mg LP), administered once daily (second phase, n = 20). The perception of contrast was analysed using a test measuring sensitivity to colour contrast yielding threshold values for sensitivity to contrast in eight spatial frequencies and three colours (red, green, blue) and in two directions (horizontal and vertical). The results of the first phase of the study demonstrated that elderly subjects showed a decrease in contrast perception in comparison with young subjects, primarily in the high frequency range, and over the full range of stimulation for direction and colour. In the second phase, elderly subjects, in comparison with young subjects, showed altered visual contrast, again in the high frequency range, but also in the low frequency range for horizontal simulation with red and blue. After 3 months of treatment with piribedil the mean contrast sensitivity threshold, over the entire frequency range, had significantly increased (P less than 0.05) for all stimulations, apart for red in the vertical direction. These results underline the value of treatment with a dopaminergic agonist, piribedil in visual disturbances in patients with dopaminergic deficiency (Parkinson patients or elderly subjects).

Aged↗
PubMed1992

Cryoinjury in human granulocytes and cytoplasts.

Although most isolated cells can be successfully cryopreserved, human granulocytes have little functional recovery after cryopreservation, even under optimized conditions. Cytoplasts, which are vesicles created from human granulocytes by depletion of organelles including granules and the nucleus, can carry out some of the complex functions of the parent granulocyte such as phagocytosis of bacteria, even after cryopreservation. Human granulocytes and cytoplasts were used in this comparative study of low-temperature responses to assess the relative importance of the plasma membrane and the granules in cryoinjury to human granulocytes. Boyle-van't Hoff plots of cell volume as a function of the reciprocal of osmolality showed that granulocytes and cytoplasts have similar osmometric behavior and equivalent osmotically inactive fractions. The hydraulic conductivities were also similar, indicating that the osmotic properties of the plasma membrane and cytoplasm were retained during preparation of the cytoplasts. Assessment of membrane integrity using fluorescein diacetate after graded freezing stresses showed that the low-temperature responses of cytoplasts were similar to those of human lymphocytes and hamster fibroblasts, with recoveries much higher than those of human granulocytes, particularly after post-thaw incubation at 37 degrees C. The results indicate that the plasma membrane is not the primary site of injury to granulocytes during freezing and thawing, and suggest that activation of cytoplasmic elements, such as granules, may constitute the early events in cryoinjury to human granulocytes. These studies have significance in approaches to the cryopreservation of granulocytes and other types of cells, such as platelets, with increased sensitivity to the conditions encountered during freezing and thawing.

Cell Membrane↗
PubMed1992

Neuropathy in chronic obstructive pulmonary disease: a multicentre electrophysiological and clinical study.

The incidence and type of neuropathy in patients with chronic obstructive pulmonary disease (COPD) were assessed. In a selected group of 89 patients, abnormal nerve conduction studies were found in 44%. Electrophysiological signs of a generalized peripheral neuropathy were found in 5-18%, depending on diagnostic criteria. Lesions which were thought to be due to compression or other forms of trauma were present in a further 24%. In the patients with peripheral neuropathy, the changes were distally predominant, affected mainly sensory fibres, and were consistent with an axonal type of neuropathy. There was a significant correlation between age and the incidence of peripheral neuropathy. Electrophysiological evidence of neuropathy was three times as common as clinical evidence. Much of the variation in the reported incidence of neuropathy in COPD is probably due to imprecise diagnostic criteria.

Adult↗
PubMed1992

Sequential treatment with low dose almitrine bismesylate in hypoxaemic chronic obstructive airways disease.

Daily dose schedules of 100-200 mg of almitrine bismesylate improve arterial blood gases in patients with hypoxaemic chronic obstructive airways disease (COPD) but dose related side effects are evident. In the present study, daily doses approximately half of those previously used were employed in a randomised double blind manner in 85 patients (age 35-79 years) with hypoxaemic COPD. After a one month period to check stability of arterial blood gases, patients were allocated to almitrine (A) or placebo (P) using an unequal code (60% A, 40% P). Tablets, 50-100 mg daily were stopped for one month after 3, 6 and 9 months to counteract drug accumulation. 50 patients in group A and 35 in group P were comparable on entry; mean age 65 (SD = 8) yrs., Pao2 7.8 (0.7) kPa (58.3 (5.0) mmHg), PaCO2 5.8 (0.8) kPa (43.2 (6.0) mmHg), forced expiratory volume in one second--FEV1 0.89 (0.25) l and 6 minute walking distance 296 (97) metres. The improvement in baseline PaO2 values was the same 0.8-1.3 kPa (6-9.8 mmHg) as with previous higher dose therapy. Approximately one third of patients did not respond, defined as PaO2 elevation > 0.67 kPa (5 mmHg). The sequential dosing scheme stabilised blood levels of almitrine within the therapeutic range of 280-300 ng.ml-1. After withdrawal of therapy arterial blood gases and spirometry reverted to pre-treatment levels, suggesting no permanent reversal of pathophysiology. Dose related side effects of breathlessness, indigestion and peripheral neuropathy were not observed. Nerve conduction studies revealed no difference in peripheral nerve dysfunction in hypoxaemic COPD between active and placebo therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Sequential administration of a reduced dose of almitrine to patients with chronic obstructive bronchopneumopathies. A controlled multicenter study].

Recent multi-centre studies have shown that high doses of Almitrine (100-200 mg per day), lead to a significant improvement in the hypoxaemia of patients presenting with chronic airflow obstruction, but that a high blood level (greater than 500 ng/ml) is often seen after 1 year, sometimes associated with signs of peripheral neuropathy. In order to maintain Almitrine blood levels in the range 200-300 ng/ml we have used an intermittent regime (with a "window" of 1 month every 3 months) and a dose limited to 100 mg per day. 102 hypoxic patients with chronic airflow obstruction, who were in a stable state were included. 65 patients were in the Almitrine group (A) and 37 patients in the placebo group (P). The treatment lasted for 1 year. In addition there was a 3 monthly follow up with arterial blood gases and spirometry, a clinical neurological examination and also electrophysiology, initially and after 6 and 12 months. 43% of patients in group A and 32% of patients in group P, left the study, most often due to poor cooperation, but sometimes as a result of side effects. After 12 months the PaO2 rose significantly in group A from 59.1 +/- 0.7 to 65.8 +/- 1.6 mmHg (p less than 0.001) whilst it was not changed in group P. The PaCO2 did not change in either group. On the other hand there was a significant fall in the subgroup of patients with hypercapnia in group A (p less than 0.001). The outcome of the neurological and electrophysiological assessments did not show any significant difference between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Is it possible to avoid a penal offence in carrying out ambulatory anesthesia?].

French jurisprudence about outpatient anaesthesia is resolutely unfavorable. It is principally based on the June 22nd 1972 decision of the cessation court, the highest court of justice in France. Preoperative non hospitalisation has been considered as a fault by negligence/carelessness of the practitioners. It resulted in their penal condemnation for involuntary injuries and compensation for the harm. This decision is linked with the evolution of the fault and the responsibility share between surgeon and anaesthetist. The post-operative phase seems to involve "theory of missing luck" (causality linkage or the detriment in itself), excluding a penal condemnation but not a partial compensation. Though some new legal considerations could be put forward, a written contract between physicians and patients is necessary in outpatient surgery, whereas the medical files and the organisation of the unit can prove the quality of medical care.

Ambulatory Surgical Procedures↗
PubMed1990

Peripheral neuropathies in patients with chronic obstructive pulmonary disease: a multicenter prevalence study.

To investigate the prevalence and type of peripheral neuropathies (PNP) in patients with chronic obstructive pulmonary disease (COPD), we studied lung function and blood gases, clinical signs of PNP, and neurophysiological function in 151 patients with COPD without known risk factors for PNP. Mean (SD) age was 65 (10) years, mean arterial PO2 was 59 (9) mmHg, mean ratio of forced expiratory volume in the first second to vital capacity (FEV1.0/VC) was 42 (12%). Thirty patients (20%) had clinically detectable and 6 (4%) had subclinical PNP of mild degree. Fourteen (9%) of the patients with clinically detectable PNP had symptoms due to PNP. Prevalence of PNP increased with severity of hypoxemia (p less than 0.05) and was more pronounced in the lower than in the upper limbs. Age and the degree of hypoxemia were predictors to differentiate between COPD patients with and without PNP. Although the cause of PNP in COPD patients remains unknown, our observations suggest that chronic hypoxemia may contribute to PNP.

Adult↗
PubMed1987

Peripheral neuropathies during hypoxaemic chronic obstructive airways disease.

Peripheral nervous system alterations during chronic obstructive airways disease (COAD) with respiratory insufficiency seem more frequent than usual neurological practice would suggest. Almost a third of COAD patients have clinical evidence of peripheral neuropathy and two thirds have electrophysiological abnormalities. The presentation consists of a polyneuropathy often subclinical or with predominantly sensory signs, which has the neurophysiological and pathological features of predominantly axonal neuropathy. The presumed etiopathogenic factors are multiple: chronic hypoxia, tobacco smoke (which contains at least three neurotoxic constituents) alcoholism, malnutrition and adverse effects of certain drugs. Hypoxia probably plays the leading part, either by direct action on nerves fibres or by enhancing the effects of other neurotoxic factors or deficiencies.

Alcohol Drinking↗
PubMed1987

Evolution of peripheral nerve function in hypoxaemic COPD patients taking almitrine bismesylate: a prospective long-term study.

Almitrine bismesylate has been thought to provoke peripheral neuropathies in patients with chronic obstructive pulmonary disease (COPD). However, there seems to exist alterations of peripheral nerve function in patients with COPD, who have not taken almitrine. We have therefore examined 22 patients with COPD and no other cause of peripheral neuropathy (PN), before and after 6 and 12 months of treatment with almitrine (50 mg bd). Seventy-eight similar patients, who did not take almitrine, were also studied (controls). Sixty-four per cent of controls, and 55% of almitrine patients initially had at least one neurophysiological abnormality. There was no change in the studied parameters after 6 months and one year's treatment with almitrine.

Aged↗
PubMed1985

Bone marrow separation, purification and cryopreservation: application for autologous bone marrow transplant (ABMT).

Autologous bone marrow transplantation is used in the treatment of patients suffering from malignant diseases. The intention of this study was to develop a technique for cryopreservation of bone marrow stem cells. A technique of purification described elsewhere (2), gave recoveries of 80% of nucleated blood cells and 87% of mononucleated blood cells after apheresis and centrifugation of buffy-coat, but when applied to bone marrow only 59% of NBC and 32% of CFUc have been harvested. We therefore modified the apheresis technique and replaced the centrifugation step by sedimentation with hydroxy-ethyl-starch. This change resulted in a small but significant increase in the yield of bone marrow cells and improved the asepsis of the procedure. From a second group of bone marrow handled with this modified protocol, final yields of 46% of NBC and 62% of MNC were obtained. After cryopreservation 87% of NBC were recovered as assessed by counting.

Adolescent↗
PubMed1978

[New therapeutic indications for a dopamine antagonist, Piribedyl].

Evidence has been found for the view that piribedil stimulates peripheral and central dopamine receptors. Piribedil stimulates the nigro-striatal pathway and has been shown to be an effective antiparkinsonian agent. The stimulation of dopamine receptors in the meso-limbic and/or meso-cortical pathways lead to propose its use in the treatment of affective disorders (maia and depression). Piribedil stimulates dopamine receptors located in the tubero-infundibular pathway and reduces the secretion of prolactine, producing ablactation ; it increases the secretion of STH. Recent studies suggest that the peripheral effects of piribedil, mainly the increases in femoral and cerebral blood flows are also due to stimulation of peripheral dopamine receptors.

Affective Symptoms↗