Search PubMed⌕ Search

Biomedical subjects

G Defer

Publications and source records attributed to G Defer.

48 records · Page 3Linked to original sources
PubMed1987

Effects of ketanserin on cardiovascular, sympatho-adrenal and endocrine systems during physical exercise in man.

Blood pressure, heart rate, oxygen consumption, plasma concentrations of catecholamines, renin, aldosterone and lactate were measured in 6 normotensive volunteers during a randomized cross-over study of oral ketanserin (20 mg X 7) and placebo; measurements were made at rest and during maximal dynamic exercise on a bicycle ergometer. At rest ketanserin reduced blood pressure without modifying heart rate or plasma noradrenaline and adrenaline. Duration of exercise and blood lactate levels did not differ between the ketanserin and the control group. During exercise only systolic blood pressure was significantly decreased on ketanserin at maximal work rate whereas heart rate did not change. Plasma noradrenaline was significantly increased and plasma aldosterone significantly decreased during exercise in ketanserin-treated subjects whereas plasma renin activity and plasma adrenaline remained unchanged. Finally, under ketanserin oxygen consumption during exercise was reduced. The results suggest that ketanserin might interfere with the sympathetic nervous system and aldosterone secretion in man.

Adrenal Glands↗
PubMed1987

Metabolic and hormonal responses to lipid and carbohydrate diets during exercise in man.

Nine healthy subjects were studied to determine their performance and the metabolic and hormonal responses to prolonged exercise after ingestion of a carbohydrate or a lipid diet. Subjects exercised on a bicycle ergometer (60% VO2max) until exhaustion four times at weekly intervals. The exercise test was performed 1 h after ingestion of three different isocaloric meals (400 Kcal) containing either glucose, medium-chain triglycerides (MCTs) or long-chain triglycerides (LCTs). The fourth test was performed after a night fast. The metabolism of these nutriments was followed using [U-13C]glucose, [1-13C]octanoate, and [1-13C]palmitate added as tracers. The average work time was comparable whatever nutriment used (116 +/- 11 min). Oxidation of the ingested nutriment over this period was 80% for glucose, 45% for MCTs, and 9% for LCTs. Glucose ingestion produced an early insulin peak associated at the end of the exercise with a lower glycemia compared to the fat diets. After MCT ingestion, an increase in ketone bodies was observed. Catecholamine response to physical exercise was decreased by all the meals when compared to fasting. Thus, we conclude that a different lipid meal, MCTs, or LCTs, compared to glucose feeding, do not modify exhaustion time in spite of differences in hormonal and metabolic responses.

Adult↗
PubMed1987

Amines for brain tomoscintigraphy.

Amines like N-isopropyl-p-123I-iodoamphetamine (IMP) and hydroxy 123I-iodobenzyl propyl diamine (HIPDM) associated with brain tomoscintigraphy have proved their worth for detecting ischaemic abnormalities. Even though the chemistry of their metabolism and their biodistribution are not fully understood, their application in the study of parenchymal impairment in stroke and reversible ischaemia yields additional information compared to the other methods of imaging like CT or MRI. The concept of a steady state in brain with a wash in/wash out model has been considered especially with IMP, to explain the evolution of the activity pattern with time when comparing early and delayed images. (This review leads to foresee the prognosis of of ischaemic diseases when redistribution is taken into account.)

Amphetamines↗
PubMed1987

Temporal evolution of brain distribution of IMP and HIPDM. Concise communication.

Early and late brain distribution of iodine-labelled N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3-propanediamine (HIPDM) and iodine labelled N-isopropyl-p-iodoamphetamine (IMP) were compared in rat and one human patient with a recent stroke in the right middle cerebral artery area. In rat, an important 'redistribution' of cerebral activity was observed in various areas of the brain, mainly white matter, whereas no such observation was made with HIPDM. In the patient, the right area was hypoactive during the early SPECT with IMP and HIPDM, and redistribution was observed in the late SPECT only with IMP. We suggest that while HIPDM appears to reflect regional cerebral perfusion, IMP distribution is dependent upon metabolic brain activity.

Aged↗
PubMed1986

Effect of nifedipine on plasma catecholamines in man at rest and during exercise.

Blood pressure, heart rate, and plasma catecholamine concentrations were measured in 9 normotensive volunteers during a randomized cross-over study of oral nifedipine (10 mg X 5) and placebo; measurements were made at rest and during maximal anaerobic exercise. At rest nifedipine reduced blood pressure and increased heart rate and plasma noradrenaline, whereas plasma adrenaline did not change. During exercise, the blood pressure response was similar in nifedipine and placebo treated subjects; however, heart rate was significantly higher with nifedipine. Plasma noradrenaline increased more during exercise in nifedipine-treated subjects. By contrast, nifedipine inhibited the increase in plasma adrenaline induced by exercise. The results suggest that peripheral vasodilatation induced by nifedipine is responsible for increased sympathetic nerve activity, both at rest and during exercise, and that nifedipine inhibits adrenaline secretion in man.

Adult↗
PubMed1986

Plasma renin activity, aldosterone and catecholamine levels when swimming and running.

The purpose of this study was to determine the response of plasma renin activity (PRA), plasma aldosterone concentration (PAC) and catecholamines to two graded exercises differing by posture. Seven male subjects (19-25 years) performed successively a running rest on a treadmill and a swimming test in a 50-m swimming pool. Each exercise was increased in severity in 5-min steps with intervals of 1 min. Oxygen consumption, heart rate and blood lactate, measured every 5 min, showed a similar progression in energy expenditure until exhaustion, but there was a shorter time to exhaustion in the last step of the running test. PRA, PAC and catecholamines were increased after both types of exercise. The PRA increase was higher after the running test (20.9 ng AngI X ml-1 X h-1) than after swimming (8.66 ng AngI X ml-1 X h-1). The PAC increase was slightly greater after running (123 pg X ml-1) than swimming (102 pg X ml-1), buth the difference was not significant. Plasma catecholamine was higher after the swimming test. These results suggest that the volume shift induced by the supine position and water pressure during swimming decreased the PRA response. The association after swimming compared to running of a decreased PRA and an enhanced catecholamine response rule out a strict dependence of renin release under the effect of plasma catecholamines and is evidence of the major role of neural pathways for renin secretion during physical exercise.

Adult↗
PubMed1985

Protein binding of propisomide.

This paper describes the protein binding of propisomide to human serum and isolated proteins using equilibrium dialysis. The drug is exclusively bound to alpha1-acid glycoprotein with high affinity. The binding is saturable even at low concentrations of the drug. Thus, the fraction unbound varied from 0.05 to 0.60 with decreasing serum concentration. The major metabolite of the drug or other drugs with affinity for alpha1-acid glycoprotein can displace propisomide from its binding site only when present in serum at high levels. Two ultrafiltration techniques are compared to equilibrium dialysis for the determination of serum protein binding of propisomide. Ultrafiltration does not give reliable results. Equilibrium dialysis is retained as an accurate method for the determination of the fraction unbound of propisomide.

Adult↗
PubMed1984

[Sarcoidosis of the central and peripheral nervous system].

The authors report two cases of Besnier -Boeck- Schaumann sarcoidosis with a neurological presentation. The first case was a 25 year old woman with a 5 year history of polyneuritis affecting the cranial and spinal nerves with very low nerve conduction times and without any detectable visceral disease. The diagnosis was made by distal bronchial biopsy. The second case was of an elderly man with tremor, difficulty in keeping his balance and deafness with chronic meningitis. The diagnosis was made by proximal bronchial biopsy, chest X-Ray showing a benign hilar lymphoma. In the first case, therapy comprised two three months courses of high dose intravenous steroids followed by oral corticosteroid therapy tailing off over three weeks. In the second case, the same intravenous steroid therapy was relayed by continuous oral steroids. The therapeutic effect was spectacular in the first case, but incomplete in the second, the intravenous steroids seeming to be more effective than the oral steroids.

Adult↗
PubMedDate not supplied

Cortical blindness during chemotherapy: clinical, CT, and MR correlations.

Two patients treated by chemotherapy for a non-Hodgkin malignant lymphoma developed focal neurological symptoms including disorientation, hemoplegia, and cortical blindness 5 and 15 days after the end of a polychemotherapy course, including methotrexate and vindesine. In both patients ECG and blood pressure were normal. Case 1 had a slight increase of protein level without cells on CSF examination and presented with a paralytic ileus. Case 2 developed an inappropriate antidiuretic hormone secretion (IADHS) syndrome. In both cases, noncontrast CT scans showed bilateral, symmetrical low density areas within the temporooccipital regions. Postcontrast CT images stressed major cortical and subcortical enhancement predominantly over the gray matter. In Case 2 the lesions also affected the right parietal lobe. Magnetic resonance scans 2-3 weeks after the onset of neurological symptoms demonstrated low intensity signal lesions on T1-weighted images and bright signal on T2-weighted images. In Case 1 the visual deficit failed to regress and in Case 2 the patient died 2 months later because of the natural evolution of her lymphoma. The clinical and radiological data suggested that a vascular ischemic process was responsible for the cerebral lesions in these two patients. As Vinca alkaloids and not methotrexate have been implicated as a cause of cortical blindness, and as our two patients presented signs of overdose of vindesine (paralytic ileus and IADHS), we suggest that the neurological and radiological abnormalities in our patients may have been due to neurotoxicity of vindesine.

Blindness↗
PubMedDate not supplied

Predictive value of (99m)Tc-HMPAO-SPECT for neurological Outcome/Recovery at the acute stage of stroke.

BACKGROUND AND PURPOSE: Combined perfusion and oxygen metabolism PET imaging is highly predictive of spontaneous outcome after middle cerebral artery (MCA) stroke, independent of clinical scores, but whether the assessment of perfusion alone by SPECT provides similar information remains unclear. We have assessed the prognostic value of (99m)Tc-HMPAO-SPECT at the acute stage of stroke. METHODS: Twenty-seven first-ever nonhemorrhagic MCA territory stroke patients were prospectively studied 4-20 h (mean: 12 h) after onset with (99m)Tc-HMPAO-SPECT. None was part of a therapeutic trial or received thrombolysis. Neurological deficits were quantified at admission and 2 months later with Orgogozo's MCA scale. SPECT images were visually classified by 3 independent observers into one of three patterns, as follows: pattern I = marked and extensive tracer hypofixation; pattern II = moderate and/or focal hypofixation with or without combined hyperfixation, and pattern III = normal or increased uptake without hypofixation. In addition to this visual analysis, we also calculated a voxel-based 'hypoperfusion score', an index of severity x extent of hypofixation according to Mountz's method. RESULTS: There was a good intra- and interobserver agreement. After consensus, 9, 14 and 4 patients were classified in patterns I, II and III, respectively. These patterns had a significant predictive value for raw outcome but not for percentage recovery (p = 0.008 and p = 0.127, respectively). Thus, all patients in pattern III had a good outcome, while most (but not all) patients in pattern I had a poor or intermediate outcome; pattern II patients were more evenly distributed among outcomes. Hypoperfusion scores were highly significantly positively correlated with both 2-month outcomes and percentage recoveries, even after controlling the predictive value of day 0 MCA scores by partial correlations. COMMENTS: We found that SPECT had a significant added predictive value even when compared to admission neurological scores. Although less accurate than PET, (99m)Tc-HMPAO-SPECT may help to predict spontaneous individual neurological evolution, especially whenever perfusion images are normal or show an increased tracer uptake without associated hypofixation.

Acute Disease↗
PubMedDate not supplied

[Central adverse effects of methylxanthines].

Methylated xanthines are responsible of minor and major side effects on the central nervous system specially seizure. A review of the literature shows that it is related in adult to different promoting factors whereas the relationship between toxicity and excessive theophylline concentration is more clear in child. Other side effects on the gastrointestinal system, sleep and cerebral circulation are discussed.

Adult↗