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Biomedical subjects

A Bes

Publications and source records attributed to A Bes.

At least 19 recordsLinked to original sources
PubMed1992

[Cerebral blood flow in migraine without aura].

For several years, cerebral blood flow (CBF) studies have been fueling the controversy surrounding the pathophysiology of migraine headache. The earliest studies focused mainly on migraine with aura (MA+) and provided evidence in support of the classical hemodynamic theory: a decrease in blood flow during the aura is followed by reactive vasodilation during the headache phase. Studies in migraine without aura (MA-), although less numerous, consistently demonstrated an increase in CBF during the attack. Olesen et al., gave rise to a heated debate by suggesting that hemodynamic manifestations are different in MA+ and MA-; in their view, CBF remains unchanged in MA-, whereas MA+ is associated with a wave of posterior blood flow deficiency which slowly spreads forwards in a manner reminiscent of experimental spreading depression; they interpret this hemodynamic pattern as evidence that the attack is mainly caused by a neural mechanism rather than a vascular spasm. This concept of MA- with no hemodynamic changes suggests that the pathophysiology of MA- may be completely different from that of MA+. However, most studies using stationary detectors or single photon emission computerized tomography (SPECT) with Xenon 133 or HMPAO as the tracer have demonstrated increased CBF during migraine attacks. The increase was not correlated with the side of the pain suggesting that vasodilatation is not the only cause of the pain. Current data do not seem to support the view that MA- and MA+ are different pathophysiologic entities; whether the mechanism of the attack is neural or vascular cannot be determined on the basis of CBF data.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrovascular Circulation↗
PubMed1988

A multi-centre, double-blind trial of tizanidine, a new antispastic agent, in spasticity associated with hemiplegia.

A double-blind study was carried out in 105 patients with chronic spasticity associated with hemiplegia in order to compare the efficacy and tolerability of tizanidine with that of diazepam. Dosage was increased progressively, if tolerated, to a maximum of 24 mg tizanidine or 30 mg diazepam per day at the end of 2 weeks. The optimum dosage was then maintained for 6 weeks. Efficacy and tolerability parameters were assessed after 2 and 8-weeks' therapy. Patients on tizanidine but not those on diazepam showed a statistically significant improvement in functional status, as assessed by walking distance on flat ground. Analysis of the stretch reflex in four groups of muscles showed that both tizanidine and diazepam reduced the duration of contractions and increased the angle at which contraction occurred, but there were no significant differences between the two drugs. Clonus of the triceps surae resolved in 48% of tizanidine and 40% of diazepam patients. Evaluation of the effect of therapy revealed an improvement with each drug in approximately 83% of patients, with the overall evaluation being slightly (but non-significantly) in favour of tizanidine. There were fewer discontinuations of treatment in the tizanidine group as a result of side-effects. It would appear, therefore, that tizanidine is an effective and well-tolerated drug in the treatment of cerebral spasticity.

Adolescent↗
PubMed1987

Reversibility of hemodynamic hypofrontality in schizophrenia.

Regional cerebral blood flow (CBF) was studied in 51 young schizophrenics. A significant decrease of CBF was seen in frontal and prefrontal regions (hypofrontal pattern) in chronic patients whose disease had evolved for more than 2 years and who were in remission. This hypofrontal pattern was reversible, as it disappeared during exacerbation of the disease. In 10 patients who had not been treated with neuroleptics for several weeks, we found a dopaminergic hypersensitivity in the frontal lobes, as a weak dose of piribedil restored near-normal frontality. This may reflect either the role of neuroleptic washout or a primitive dopaminergic depletion, as proposed by some authors in the chronic form of schizophrenia.

Adult↗
PubMed1987

[A case of centronuclear myopathy in adults with facio-scapulo-peroneal topography].

A 34 year-old man had complained since childhood of weakness of the right lower limb. His mother had a myopathy. Examination showed weakness and amyotrophy of the antero-external regions of the legs, mainly on the left, moderate weakness of the right scapular girdle and slight facial weakness. Serum creatine kinase was increased. Electromyogram and CT scan images were of the myogenic type. Biopsy showed a centronuclear myopathy. The course was slowly progressive. Centronuclear myopathy is rare in adults. The facio-scapulo-humeral localization has been described in numerous other pathologic types of myopathy.

Adult↗
PubMed1986

[Acebutolol and cerebral blood flow of the moderately hypertensive aged subject].

In 17 moderate hypertensive patients (mean age = 67 +/- 8.8) the effects of a chronic oral administration of the beta blocking agent acebutolol on regional cerebral blood flow (rCBF) was studied using the non invasive 133 Xenon inhalation technique. The results was compared to the rCBF obtained in an age matched normal control group. Our study shows that during long term therapy low doses of acebutolol (200 mg/daily) the rCBF is unaffected by a decrease (20 mmHg) of the mean arterial blood pressure. The relative hypofrontality of the elderly hypertensive patients leads to be corrected by acebutolol.

Acebutolol↗
PubMed1986

[Migraine and the idiopathic Raynaud phenomenon].

The successive onset of spasms of distal arteries of the limbs and complicated migraine in a young migrainous woman raised the possibility of a common mechanism for both disorders. Three similar cases have been reported and two recent epidemiological studies have shown the frequent association of migraine attacks and Raynaud's phenomenon or variant angina in a individual patient. The possible role of vasospasm in triggering the migrainous aura is discussed.

Adult↗
PubMed1985

Epinephrine, norepinephrine, and dopamine during a 4-day head-down bed rest.

Head-down bed rest at an angle of 6 degrees was used as an experimental model to simulate the hemodynamic effects of microgravity, i.e., the shift of fluids from the lower to the upper part of the body. The sympathoadrenal activity during acute (from 0.5 to 10 h) and prolonged (4 days) head-down bed rest was assessed in eight healthy men (24 +/- 1 yr) by measuring epinephrine (E), norepinephrine (NE), dopamine (DA), and methoxylated metabolite levels in their plasma and urine. Catecholamine (CA) and methoxyamine levels were essentially unaltered at any time of bed rest. Maximal changes in plasma were on the second day (D2): NE, 547 +/- 84 vs. 384 +/- 55 pg/ml; DA, 192 +/- 32 vs. 141 +/- 16 pg/ml; NS. After 24 h of bed rest, heart rate decreased from 71 +/- 1 to 63 +/- 3/min (P less than 0.01). Daily dynamic leg exercise [50% maximum O2 uptake (VO2 max)] used as a countermeasure did not alter the pattern of plasma CA during bed rest but resulted in a higher urinary NE excretion during postexercise recovery (+45% on D2; P less than 0.05). The data indicate no evident relationship between sympathoadrenal function and stimulation of cardiopulmonary receptors or neuroendocrine changes induced by central hypervolemia during head-down bed rest.

Adult↗
PubMed1978

Hemodynamic and metabolic factors in human cerebral ischemia.

Hemodynamic and metabolic cerebral measurements (CBF, CMRO2, CMRG, CSF) were evaluated in stroke patients. To investigate the effects of chronic cerebral circulatory insufficiency, CBF and CMRO2 were also studied. Further nontraumatic investigations of CBF measurement will allow a better understanding of clinical cases.

Acidosis↗
PubMed1977

[Benign intracranial hypertension due to thrombosis of a transverse sinus. Diagnosis by scintigraphy using bleomycin labelled with cobalt 57 (author's transl)].

In a case of benign intracranial hypertension with no apparent aetiology, cerebral scintigraphy demonstrated abnormal uptake in the left transverse sinus 24 hours after injection of the isotope. This sinus was seen to be thrombosed by cerebral angiography. On the basis of this case, the role of cerebral venous thrombosis in cases of "pseudo-tumor cerebri" is discussed.

Adult↗