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Biomedical subjects

A Barbeau

Publications and source records attributed to A Barbeau.

At least 181 records · Page 10Linked to original sources
PubMed1976

Neurologically active peptides.

This paper reviews recent evidence that a number of small peptides found in the brain are active in the central nervous system and behaviorally. Attention is focused on MSH/ACTH 4-10, alpha- and beta-MSH, and the prohormone beta-LPH, as they produce a syndrome of yawning and stretching. Studies with substance P and mainly with MIF-I are also reviewed. It is shown that substance P is an excitatory transmitter or modulator in the dorsal spinal cord with that MIF-I has antiparkinson properties. It is concluded that many polypeptides have direct actions on the central nervous system independent of their neuroendocrine properties.

Adrenocorticotropic Hormone↗
PubMed1976

Quebec cooperative study of Friedreich's ataxia: design of the investigation.

The general outline of the complete prospective study of 50 cases of spino-cerebellar degeneration is given. The general protocol followed, the criteria for inclusion and the mode of analysis are described. The aim of this study was to establish a base of clinical, physiological and biochemical facts upon which a logical and systematic approach to pathogenesis and treatment of Friedreich's ataxia could be attempted.

Friedreich Ataxia↗
PubMed1976

Clinical description and roentgenologic evaluation of patients with Friedreich's ataxia.

The 50 patients in this survey were classified by a panel of neurologists into 4 clinical sub-groups: Group Ia ("typical" Friedreich's ataxia, complete picture), Group Ib ("typical" Friedreich's ataxia, incomplete picture), Group IIa ("atypical" Frriedreich's ataxia, possible recessive Roussy-Levy syndrome), Group IIb (heterogeneous ataxias). The clinical symptoms and signs were analyzed for each of these groups. A constellation of signs constantly present in Friedreich's ataxia and obligatory for diagnosis was described. Other important symptoms, such as the Babinski sign, kyphoscoliosis and pes cavus were found to be progressive, but not essential for the diagnosis at any given time. Finally, a host of other symptoms can only be called accessory. The progression of scoliosis was found to be an important tool in the differential diagnosis of ataxias. Our study also indicates, in contrast to the opinion of some authors, that absent deep tendon reflexes in the lower limbs and early dysarthria are essential in "typical" Friedreich's ataxia.

Adolescent↗
PubMed1976

Genetic and family studies in Friedreich's ataxia.

This study consists of two parts: 1. A detailed genetic analysis of 35 sibships in which 58 individuals were affected with Friedreich's ataxia; and 2. Clinical and laboratory examinations of parents and siblings, in an attempt at carrier detection and diagnosis of the pre-clinical state. The increased parental consanguinity, the lack of affected individuals in other generations, and the lack of significance of extrinsic etiological variables, all suggested an autosomal recessive mode of inheritance, and this was confirmed by formal genetic analyses, employing several different methods. Associated abnormalities in our series of 58 patients included cardiomyopathy (51.7%), diabetes mellitus (19.0%), optic atrophy (5.2%), nerve deafness (5.2%) and congenital malformations (6.9%). The incidence of diabetes mellitus, congenital malformations, and epilepsy and/or febrile convulsions was elevated in first degree relatives of patients with Friedreich's ataxia.

Adolescent↗
PubMed1976

Friedreich's ataxia: preliminary results of some genealogical research.

A preliminary genealogical investigation of all the known ancestors from the year 1608 of 4 apparently unrelated French Canadian kindreds with Friedreich's ataxia reveals that the original ataxia gene in the province of Quebec was present within a core of no more than 10 families living in Quebec City in the mid-1600's.

Consanguinity↗
PubMed1976

Nerve conduction studies and electromyography in Friedreich's ataxia.

Twenty-six of 50 patients were investigated with nerve conduction studies and electromyography using a standard protocol and were compared to the findings in 50 normal control subjects. Almost all cases of typical Friedreich's ataxia had absent sensory action potentials (SAP) in the digital (92%) or sural (96%) nerves. The others had markedly decreased S.A.P's. In these same patients motor conduction velocities were either normal or only slightly decreased. In the second, atypical group of 9 patients, the motor conduction velocities were considerably decreased. Because of the absence of sensory action potentials in Friedreich's ataxia, and that the absence was noted in our very mild cases, it is proposed that this measure be used to facilitate early diagnosis.

Action Potentials↗
PubMed1976

Cardiological signs and symptoms in Friedreich's ataxia.

The cardiovascular signs and symptoms were recorded in 36 patients with typical Friedreich's Ataxia (Group Ia, Ib). Seventeen patients were asymptomatic and this did not correlate with the severity of the disease. No pathognomonic clinical constellation was found to reveal the underlying cardiomyopathy.

Adolescent↗
PubMed1976

Electrocardiographic and vectocardiographic findings in Friedreich's ataxia.

Electrocardiographic and vectocardiographic changes are frequent in Friedreich's ataxia. In one of 35 patients both tests were normal. The vectocardiogram is more explicit in demonstrating the severity of the QRS changes with a right ventricular hypertrophy pattern present in 60% of cases. Serial examination of ECG tracings are recommended to monitor the cardiomyopathy in this progressive neurological disorder, in order to detect the onset of congestive heart failure, significant tachyarrythmias, or obstructive cardiomypathy.

Atrial Fibrillation↗
PubMed1976

Echocardiographic findings in Friedreich's ataxia.

Echocardiographic examination of 21 patients with Friedreich's ataxia (age 7 to 28 years) showed cardiac abnormalities in 90% of the cases. They were characterized by varying degrees of septal hypertrophy in 81%, left ventricular free wall hypertrophy in 61%, and a slight reduction of left ventricular internal dimension in 57% of the cases. Asymmetric septal hypertrophy (ASH) with a septal/left ventricular free wall ratio of over 1.3 was found in 29% of the cases, and systolic anterior motion (SAM) of the mitral valve in three patients. Two other patients showed evidence of a different type of cardiomyopathy with marked symmetric left ventricular hypertrophy and marked left ventricular enlargement.

Adolescent↗
PubMed1976

Hemodynamic findings in Friedreich's ataxia.

Thirteen patients with classical Friedreich's ataxia underwent cardiac catheterization with recordings of retrograde cardiac pressures, measurements of cardiac output and calculation of the left ventricular volumes and mass. The cardiomyopathy in Friedreich's ataxia falls into the hypertrophic group of cardiomyopathies with decreased compliance of ventricular myocardium, varying degrees of concentric and asymmetric hypertrophy and outflow tract obstruction. Although there is no clear parallel between the degree of abnormal hemodynamic findings and the degree of neurological impairment, severely handicapped patients may present a diffusely hypertrophied and hypokinetic left ventricular myocardium.

Adolescent↗
PubMed1976

Cardiac angiographic findings in Friedreich's ataxia.

Angiograms of 12 patients with typical Friedreich's ataxia were analyzed. The results corroborate previous reports and justify the conclusion that the cardiomyopathy is of the hypertrophic type. In 10 of 12 cases, the hypertrophy is concentric, and non obstructive. Less frequently (2 cases), this hypertrophy is accompanied by diffuse hypokinesis and depressed ejection fraction.

Angiocardiography↗
PubMed1976

Pathology of the heart in Friedreich's ataxia: review of the literature and report of one case.

A single case of typical Friedreich's ataxia was analyzed for cardiac changes and compared to the findings from the literature. Macroscopically, there was a cardiomegaly with some degree of ventricular hypertrophy and probable mild dilatation of the auricles. The more important and constant histologic changes were myocardial fibrosis and degeneration of the cardiac muscle cells. Granular deposits of calcium salts and iron were found in the muscle cells. A cardiomyopathy hypertrophic in type and occasionally obstructive appears to be an integral part of Friedreich's ataxia.

Adult↗
PubMed1976

Clinical laboratory findings in Friedreich's ataxia.

All clinical laboratory tests carried out in 4 groups of patients with the diagnosis of typical or atypical Friedreich's ataxia have been found to be within the normal range. In this prospective study of 50 patients, a number of findings previously reported to be abnormal in the literature, have not been confirmed.

Alanine Transaminase↗
PubMed1976

Glucose and insulin metabolism in Friedreich's ataxia.

Our prospective survey of 50 ataxic patients confirms the previous finding of frequent clinical or chemical diabetes in Friedreich's ataxia. Eighteen percent of our typical cases have clinical diabetes and 40% at least an abnormal glucose tolerance curve. However, this finding does not appear to be specific to that form of ataxia. Furthermore, we have shown that most patients with ataxia have normal or low fasting insulin levels, but a hyperinsulinic response to a glucose load.

Blood Glucose↗
PubMed1976

Bilirubin metabolism - preliminary investigation.

In our studies, high total bilirubin values in the plasma were noted in cases of Friedreich's ataxia. A bimodal distribution of the values indicated the possible presence of two subgroups of patients. In these kindred, we demonstrated an elevation in unconjugated bilirubin with features similar to those reported in Gilbert's syndrome: normal liver function tests, elevation after fasting and day to day variability. We also report preliminary experiments indicating that bilirubin levels may be taurine dependent. We postulate that the defect could be a secondary component of the ataxic disease, possibly indicating a defect in membrane transport.

Bilirubin↗
PubMed1976

Amino acid metabolism in Friedreich's ataxia.

A study of amino acids determined by sequential Multi-sample Amino Acid Automatic Analyzer in plasma, urine and cerebrospinal fluid (CSF) in patients with Friedreich's ataxia and control subjects has revealed a number of mathematically significant variations from normal. Of practical physiological importance are the following: a high urinary excretion of alanine with slightly elevated plasma levels; a low plasma and CSF concentration of aspartic acid in the presence of normal urinary values and finally a low CSF concentration of taurine accompanied by normal plasma levels, but elevated urinary output and renal clearance rates. We postulate that the modifications in alanine and aspartic acid are less specific and probably secondary, but there could be a genetic defect in the membrane transport of taurine and the other beta-amino acids in Friedreich's ataxia.

Alanine↗