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Biomedical subjects

A Carolei

Publications and source records attributed to A Carolei.

At least 55 records · Page 3Linked to original sources
PubMed1991

Quantitative assessment of cerebral blood flow in partial epilepsy using Xe-133 inhalation and SPECT.

The Xe-133 inhalation method was used to study rCBF in 12 patients with partial epilepsy during the interictal phase. SPECT images evidenced a focal CBF defect in 10 out of 12 patients, while quantitative analysis showed CBF abnormalities in all the patients. The focal CBF defect corresponded to the site of EEG abnormalities in nine patients. Additional low-flow areas beyond the EEG focus were found. Five patients presented a significant CBF decrease in the cerebellar hemisphere contralateral to the EEG focus. In five patients with unilateral EEG abnormalities, a CBF reduction was found in the contralateral cerebral hemisphere, mirror to the EEG focus. Finally, a widespread CBF decrease involving one or both cerebral hemispheres was observed in seven patients. Global and rCBF values were not correlated with age, duration of disease, frequency of seizures, secondary generalization, or specific therapy. SPECT may be useful in evaluating EEG epileptic foci, and quantitative SPECT allows the detection of functional effects of the epileptic focus on anatomically connected remote areas, probably due to the decrease of afferent inputs (diaschisis phenomenon).

Administration, Inhalation↗
PubMed1991

Transcranial Doppler in acute hemispheric brain infarction.

We studied cerebrovascular anatomy using intra-arterial digital angiography, and blood flow velocity in the middle cerebral artery (MCA) using transcranial Doppler (TCD) ultrasonography in 42 patients with acute hemispheric ischemic brain infarction. We compared angiography with TCD and the clinical findings within 6 hours of the onset of symptoms. The location and extent of the chronic ischemic brain damage was assessed by CT performed 1 to 3 months after the ictus. Abnormal TCD, as manifested by either an unobtainable MCA flow signal or a significantly depressed MCA flow velocity, was highly associated with proximal MCA occlusions demonstrated by angiography. Abnormal TCD predicted both larger chronic CT lesions and more extensive ischemic change within the MCA territory. These data demonstrate that early TCD conveys useful information concerning cerebral tissue prognosis following hemispheric ischemia.

Adult↗
PubMed1991

[Cerebral vascular damage in hypertension].

Hypertensive vascular lesions in the brain include increased formation of atheroma, lacunae and lacunar infarctions, atherothrombotic brain infarction and vascular dementias such as multi-infarct dementia and Binswanger's disease. Hypertension is also associated with an increased risk of intracerebral and subarachnoid hemorrhage. Reduction of arterial pressure with antihypertensive agents can prevent the occurrence and limit the extent of stroke.

Cerebrovascular Disorders↗
PubMed1991

Monosialoganglioside GM1 in cerebral ischemia.

In vitro studies have shown that monosialoganglioside GM1 reduces excitatory amino acid-related neurotoxicity by limiting the downstream consequences of abusive excitatory amino acid receptor stimulation, while enhancing neuronotrophic factor action in a variety of neuronal cell types. Systemic administration of GM1 appears to be efficacious in reducing acute nerve cell damage and in facilitating medium- and long-term functional recovery after brain injury. Although the mechanism of action remains unclear, it appears likely that GM1 protective effects in the acute injury phase are at least in part due to the attenuation of excitotoxicity, while the long-term functional recovery might reflect GM1 potentiation of neuronotrophic factors. The potential therapeutic efficacy of GM1 administration in different conditions in humans, as suggested by pioneer clinical studies, is reviewed. Further larger, randomized, double-blind clinical studies are necessary to define the therapeutic efficacy.

Brain Ischemia↗
PubMed1991

Controlled clinical trials in stroke.

Reasons for the unsatisfactory number and reliability of most trials on the pharmacological treatment of acute cerebral ischemia are reviewed, focusing mainly on the clinical aspects of the issue. The opportunity of early intervention, supported by current pathophysiological hypotheses, is recognized. Past and recent Italian trials on ischemic stroke patients evaluated and treated within the first 6 h from onset are reported, also mentioning the results of a study including early cerebral angiography and SPECT (Single Photon Emission Computed Tomography). Early fibrinolytics associated to brain protecting agents are regarded as the future choice in clinical trials of acute cerebral ischemia.

Cerebrovascular Disorders↗
PubMed1990

Cerebral blood flow and plasma volume during hyperglycemia in the conscious rat.

Cerebral blood flow (CBF) and cerebral plasma volume (CPV) were measured under steady-state hyperglycemic conditions in the hemispheres and brainstem-cerebellum of conscious rats. There groups of hyperglycemic animals each having a different level of plasma glucose concentration, 25, 33.3, 44.4 mmol/l, and a normoglycemic control group were studied. CBF was not affected at the hyperglycemic levels of 25 and 33.3 mmol/l. Mean hemispheric and brainstem-cerebellum CBF values appeared lower than in controls at the highest glycemic level although the differences were not statistically significant. CPV was found to be unchanged at the hyperglycemic level of 25 mmol/l, while it was found to be increased in the hemispheres of the animals whose plasma glucose concentration had been elevated to 33.3 and 44.4 mmol/l. The results of the study do not support the claim that hyperglycemia may enhance ischemic brain injury by reducing CBF.

Animals↗
PubMed1990

Pathophysiology of ischemic brain disease.

In this article, we review and discuss the pathophysiology of brain ischemia, focusing on requirements of cerebral metabolism, biochemical characterization of the energy reserve, and autoradiographic and tomographic methods for in vivo evaluation of cerebral blood flow and metabolism. We propose new therapeutic strategies for the management of the acute phase of stroke, based on diagnostic protocols that include clinical evaluation, noninvasive study of neck and intracranial arteries, brain computed tomography, and single-photon emission computed tomography. The ideal therapeutic trial should combine early thrombolysis and active brain protection against those biochemical mechanisms leading to irreversible neuronal damage.

Animals↗
PubMed1989

Systemic hypertension as a treatable risk factor for cerebrovascular disease.

It has long been established that hypertension is the major risk factor for stroke. Three Italian studies have been reviewed in order to examine different aspects of the problem. In the first study, the role played by the systolic, diastolic and systodiastolic components of hypertension in causing atherosclerotic damage of extracerebral and intracerebral arteries was examined. At the extracranial level, a significant correlation between systolic hypertension and atherosclerotic lesions was evident. The second study evaluated the risk of major stroke, myocardial infarction and death in patients with transient ischemic attacks and reversible ischemic neurologic deficits. Possible prognostic predictors of these events were thoroughly considered: Cumulative survival with the multivariate Kaplan-Meier analysis was significantly lower in hypertensive than in normotensive subjects, particularly for cerebral deaths and for all deaths. The third study was aimed at assessing the risk factors for transient ischemic attacks and stroke in young adults. Again, hypertension emerged as a fundamental risk factor, significantly more frequent in the subgroup of older patients than in the younger subgroup.

Age Factors↗
PubMed1988

One year follow-up of patients clinically preselected for excessive risk of stroke.

From a consecutive series of 812 patients at risk of stroke we selected 100 who seemed to be at high risk (excessive stroke risk--ESR) on the following clinical criteria: either multiple reversible ischemic attacks in one carotid territory or multiple (or bilateral) severe stenotic carotid lesions. The patients of the first subgroup received medical therapy and those of the second were referred for surgery. The 100 patients were followed up for 12 months, during which 29 patients had cerebral ischemic events: 17 having stroke and 12 TIA. This study suggests that it is possible to identify beforehand subgroups of ESR patients, thereby facilitating the selection of patients for brain protection and avoiding huge trials of unselected cerebrovascular patients.

Aged↗
PubMed1988

Changing prognosis of primary intracerebral hemorrhage: results of a clinical and computed tomographic follow-up study of 104 patients.

One hundred four consecutive cases of primary intracerebral hemorrhage hospitalized at the time of stroke were followed until death or for 1 year. All were treated nonsurgically. The 30-day mortality rate was 30%. Good clinical outcome and complete resolution of the lesion on computed tomography were observed in 49 and 13% of patients, respectively. Age, state of consciousness, and size of the hemorrhage on computed tomography scan were reliable prognostic indicators. The long-term survival rate, 66%, was higher than that previously reported and should be considered in future trials evaluating medical and surgical treatment of intracerebral hemorrhage.

Adult↗
PubMed1987

Sequential computed tomography and 123I-HIPDM scans in multiple sclerosis with large plaque. A case report.

We report a case of acute multiple sclerosis in whom computed tomography (CT) scan suggested the presence of a large plaque. The anatomical and functional recovery of the brain tissue was followed by means of repeated CT scan and 123I-HIPDM studies. Single photon emission CT may be successfully employed to monitor the pathophysiological changes associated with the demyelinating process.

Adult↗
PubMed1986

Preliminary histochemical and electron microscopic observations on the nervous system of hydra.

The nervous system of a primitive Coelenterate (Chlorohydra viridissima) has been studied using ultrastructural and histochemical techniques. The authors confirm the ultrastructural pattern of nerve cells described by Lentz and coworkers. Reserpine treatment fails to induce any reduction of catechol- and indoleamine content visible to histochemical observation. In vivo treatment with tetanus toxin does not induce behavioural changes and no specific binding of toxin is revealed by immunocytological analysis. This suggests that neuron tetanus toxin receptor sites are absent in hydra. Hydra nerve cells must therefore be considered as extremely primitive elements, which the Authors consider to support the hypothesis of neurons having originated as a gradual differentiation of myoepithelial cells, as proposed by Pantin (1956) and by Passano (1963).

Animals↗
PubMed1985

Focal cerebral ischemia and migraine.

Consistent literature data on the cerebrovascular risk in migraineous patients are lacking. Available preliminary clinical data (Italian Cooperative Cross-Sectional Case-Control Study) suggest that migraine can hardly be considered a relevant pathogenetic associated risk factor of focal cerebral ischemia.

Adult↗
PubMed1984

Aminergic neurotransmitters and adenylate cyclase in hydra.

Serotonin, dopamine and, in lesser amounts, norepinephrine were detected in Chlorohydra viridissima with electrochemical detection coupled to liquid chromatography (LCED). Treatment with reserpine induces a significant decrease in amine levels. Adenylate cyclase was found in Hydra tissue; the enzyme is stimulated by Mg, Mn and F and sensitive to guanine nucleotide activation. Dopamine, serotonin, GSH and glutamate do not affect cyclase activity.

Adenylyl Cyclases↗
PubMed1984

A placebo-controlled study of the antidepressant activity of moclobemide, a new MAO-A inhibitor.

Preliminary open trials performed by the authors and others with Moclobemide, a new MAO-A inhibitor, indicated that the drug has a satisfactory antidepressant activity. In the present double-blind study Moclobemide has been compared to placebo in a group of 34 unipolar psychotic or neurotic depressed patients. The mean daily dose of Moclobemide was 297 mg and treatment lasted from two to four weeks. Drug effectiveness was measured by improvements in the Hamilton Rating Scale for Depression (HRSD), Clinical Global Impression (CGI) and 100 mm Visual Analogue Scale (VAS). The results have shown that the active drug was markedly superior to placebo. The mean total score of HRSD was reduced from 41.7 to 16.5 in 18 pts. treated with Moclobemide and from 36.3 to 29.1 in 16 pts. who received placebo. Self-assessment with VAS showed a mean reduction from 82.7 mm to 42.2 mm and from 84.3 to 70.6 mm respectively. Moderate to marked improvement was observed by the CGI in 15 cases treated with Moclobemide and mild to moderate in 5 cases who received placebo. The treatment was well tolerated.

Adult↗