scholarly journals Purine Metabolism in Friedreich's Ataxia

Author(s):  
P. Draper ◽  
B. Lemieux ◽  
I. H. Fox ◽  
D. Shapcott

SUMMARY:In a detailed investigation of nucleotide synthesis, intercom'ersion and degradation, no difference was found between subjects with Friedreich's Ataxia and normal controls. It appears improbable that this disorder is related to a primary defect in purine metabolism.

Author(s):  
S.B. Melancon ◽  
M. Vanasse ◽  
G. Geoffroy ◽  
L. Barabe ◽  
A. Proulx ◽  
...  

SUMMARY:Twenty-two patients with Friedreich’s Ataxia and ten normal controls were followed for one year and assessed as to their clinical performance after two successive six-month periods of lecithin or safflower oil. Results demonstrated no significant difference in performance scores according to group assignation, neither in patients nor in controls. According to stages, two patients in stage I and to a lesser degree, one patient in stage IV showed better scores for muscle strength and some motor accuracy and coordination tests with lecithin. Controls as groups maintained positive scores in all tests. Patients as groups showed negative mean values in nine out of eleven tests. Again as groups, patients receiving safflower oil demonstrated a mean 8% less deterioration than patients receiving lecithin. This study demonstrates that objective clinical tests and the participation of normal controls are a must in a therapeutic trial implicating patients with a progressive disorder such as Friedreich’s Ataxia. The possible role of linoleic acid as the active factor from which clinical improvement proceeded in some specific patients and with early functional stages of the disease, has to be considered and reevaluated in the near future.


Author(s):  
M.J. Taylor ◽  
J.B. McMenamin ◽  
E. Andermann ◽  
G.V. Watters

ABSTRACT:Auditory brainstem responses (ABRs) and cortical auditory evoked responses (AERs) were studied in a series of 16 Friedreich’s ataxia patients who varied in age, degree of clinical involvement and duration of the disorder. The ABRs were markedly abnormal in all but the youngest patient, and the abnormalities reflected the severity and duration of the disease. The latencies of the AERs were significantly longer in the Friedreich’s ataxia patients compared to normal controls, suggesting cortical as well as peripheral involvement of the auditory system. These data are discussed in terms of the neuropathology of the disorder and the similarities with the other sensory systems in Friedreich’s ataxia patients.


Author(s):  
S. B. Melançon ◽  
M. Potier ◽  
L. Dallaire ◽  
G. Fontaine ◽  
B. Grenier ◽  
...  

SUMMARY:Lipoamide dehydrogenase was measued in cultivated skin fibroblasts from twelve patients with Friedreich's ataxia and nine normal controls. No difference in specific activity, subcellular distribution and Vmax or Km was observed between patients and controls.


Author(s):  
A. Barbeau ◽  
F. Patenaude ◽  
G. Nadon ◽  
M. Charbonneau ◽  
T. Cloutier

SUMMARY:The taurine urinary excretion pattern, before and after an oral load of 250 mg taurine, was studied in normal control subjects and in patients with typical Friedreich’s ataxia. It was demonstrated that in both situations the ataxic patients fell within the sub-types of “intermediate” and “high taurine excretors”, while none were “low taurine excretors”. It was also demonstrated that the excretion of taurine after a load in the obligate heterozygotes parents of the ataxic patients was intermediate between normal controls and patients. It is postulated that patients with Friedreich’s Ataxia lack normal regulation of the high affinity-low capacity uptake system for taurine (the TH system) in the brush border of kidney tubules. The low affinity-high capacity uptake system in the same membranes (the TL system) appears to be normal in Friedreich’s patients. The normal allele could be called THN and the variant THF and this trait would be inherited in an autosomal recessive fashion if it is linked to the Freidreich phenotype. Whether this finding is or is not the basic genetic defect in Friedreich’s Ataxia will require more studies to clarify, but it is of interest to note that a similar pattern appears to be present in the fibroblasts of these patients.


Author(s):  
S.B. Melancon ◽  
L. Dallaire ◽  
M. Potier ◽  
M. Vanasse ◽  
P. Marois ◽  
...  

SUMMARY:A clinical and biochemical evaluation of twenty-two patients with Friedreich’s Ataxia and ten normal controls was undertaken in 1980 to assess the effect of lecithin and linoleic acid supplements on the course of the disease. The trial consisted of two consecutive six months periods on either supplements in a double-blind crossover fashion. Clinical appraisal was performed with regards to the following parameters: joints mobility, muscle strength, equilibrium, coordination, motor accuracy, speech and numerous day to day activities. Blood samples were obtained at the beginning and in the course of the trial for enzymatic determinations. This paper describes the methodology of the study.


Author(s):  
J.M. Peyronnard ◽  
L. Charron ◽  
A. Barbeau

SummaryTwo female patients aged 30 and 40 years with the Charlevoix-Saguenay ataxia were studied. Both had absent sensory action potentials in upper and lower extremities but, unlike typical cases of Friedreich's ataxia, they displayed a marked slowing of motor conduction velocities. Sural nerve biopsies taken from calf and ankle revealed a severe loss of large my elina ted axons contrasting with a normal myelinated fiber density. Evidence for active axonal degeneration was scarce, with no indication of axonal regeneration.Teased myelinated fibers revealed an increased variability of internodal length but no evidence for myelin breakdown. These findings support, as a primary defect, a developmental abnormality of peripheral nerve, namely a lack of maturation of large myelinated axons and possibly a faulty myelination of nerve fibers. We think it is unlikely to represent a progressive axonal atrophie or dystrophic process, as suggested in Friedreich's ataxia.


Author(s):  
B. Bertagnolio ◽  
G. Uziel ◽  
E. Bottachi ◽  
G. Crenna ◽  
A. D’Angelo ◽  
...  

SUMMARY:Pyruvate and palmitate oxidations by cultured fibroblasts suspensions were measured in optimized conditions and proved to be within normal range in the cells from Friedreich's patients. However, when pyruvate oxidation was measured by direct assay of the pyruvate dehydrogenase complex, this enzyme activity proved to be significantly lower in Friedreich's than in controls' cells. These abnormalities were not observed when the cells were sonicated. Moreover, lipoamide dehydrogenase activity. Km and Vmax were within the normal range in Friedreich 's cells. These data suggest that the low activities of the PDH complex are not a primary defect in Friedreich's ataxia, but are more likely related lo membrane abnormalities in Friedreich's cells.


1986 ◽  
Vol 25 (2) ◽  
pp. 84-91 ◽  
Author(s):  
E. Cassandro ◽  
F. Mosca ◽  
L. Sequino ◽  
F. A. De Falco ◽  
G. Campanella

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