1,721,002 research outputs found
Subacute sensory ataxia and optic neuropathy with thiamine deficiency
No full textBackground. A 71 year-old man with a history of partial gastrectomy presented to the emergency department with subacute gait instability associated with painful dysesthesias and clumsiness in both hands. 10 years before presentation he had received a diagnosis of megaloblastic anemia, with no neurological involvement, as a result of vitamin B 12 and folate deficiency, for which he was receiving regular supplements.Investigations. Neurological examination; routine laboratory testing; MRI of the spine and brain; lumbar puncture; electromyography; sensory, motor and visual evoked potentials, optic nerve optical coherence tomography; immunoelectrophoresis; cryoglobulins; immunological and infection tests; screening for onconeural antibodies; measurement of serum metabolic values, including vitamins B 12 and E, folates, homocysteine, copper, zinc and pyruvic acid; transketolase activity; gastrointestinal endoscopies; and the glucose breath test.Diagnosis. Subacute sensory ataxia with bilateral optic neuropathy related to thiamine deficiency resulting from remote partial gastrectomy.Management. Parenteral thiamine supplementation followed by chronic oral thiamine and short-term, low-dose multivitamins. © 2010 Macmillan Publishers Limited. All rights reserved
Comparative assessment of respiratory chain and antioxidant enzymatic methods in skeletal muscle biopsies
No full textMitochondrial disorders of the nuclear genome
Full text linkBACKGROUND: Mitochondrial myopathies are regulated by two genomes: the nuclear DNA, and the mitochondrial DNA. While, so far, most studies have dealt with mitochondrial myopathies due to deletions or point mutations in the mitochondrial DNA, a new field of investigation is that of syndromes due to mutations in the nuclear DNA. These latter disorders have mendelian inheritance.
RESULTS: Three representative cases have been selected: one with COX deficiency and a Leigh syndrome due to a SURF1 gene mutation, one due to a defect of Coenzyme Q synthesis and one with dominant optic atrophy due to a mutation in the OPA1 gene.
CONCLUSIONS: Future developments will show that many neurodegenerative disorders are due to mutations of nuclear genes controlling mitochondrial function, fusion and fission
Impaired Copper and Iron Metabolism in Blood Cells and Muscles of Patients Affected by Copper Deficiency Myeloneuropathy.
No full textAbstract
AIMS:
Severe copper deficiency leads to a treatable multisystem disease characterized by anaemia and degeneration of spinal cord and nerves, but its mechanisms have not been investigated in humans. We tested whether copper deficit leads to alterations in fundamental copper dependent proteins and in iron metabolism in blood cells and muscles of patients affected by copper deficiency myeloneuropathy, and if these metabolic abnormalities are associated with compensatory mechanisms for copper maintenance.
METHODS:
We evaluated the expression of critical copper-enzymes, of iron-related proteins, and copper chaperones and transporters in blood and muscles from five copper deficient patients presenting with subacute sensory ataxia, muscle paralysis, steatosis, and variable anaemia. Severe copper deficiency was caused by chronic zinc intoxication in all of the patients, with an additional history of gastrectomy in two cases.
RESULTS:
The antioxidant enzyme SOD1 and subunit 2 of cytochrome c oxidase were significantly decreased in blood cells and in muscles of copper-deficient patients compared to controls. In muscle, the iron storage protein ferritin was dramatically reduced despite normal serum ferritin, and the expression of the heme-proteins cytochrome c and myoglobin was impaired. Muscle expression of the copper transporter CTR1 and of the copper chaperone CCS, were strikingly increased, while antioxidant protein 1 was diminished.
CONCLUSIONS:
Critical copper-dependent enzymes involved in antioxidant defenses, in mitochondrial energy production, and in iron metabolism are affected in blood cells and muscles of patients with profound copper deficiency leading to myeloneuropathy. Homeostatic mechanisms are strongly activated to increase intracellular copper retention
Assessment of mitochondrial respiratory chain enzymatic activities on tissues and cultured cells.
No full textThe assessment of mitochondrial respiratory chain (RC) enzymatic activities is essential for investigating mitochondrial function in several situations, including mitochondrial disorders, diabetes, cancer, aging and neurodegeneration, as well as for many toxicological assays. Muscle is the most commonly analyzed tissue because of its high metabolic rates and accessibility, although other tissues and cultured cell lines can be used. We describe a step-by-step protocol for a simple and reliable assessment of the RC enzymatic function (complexes I-IV) for minute quantities of muscle, cultured cells and isolated mitochondria from a variety of species and tissues, by using a single-wavelength spectrophotometer. An efficient tissue disruption and the choice for each assay of specific buffers, substrates, adjuvants and detergents in a narrow concentration range allow maximal sensitivity, specificity and linearity of the kinetics. This protocol can be completed in 3 h
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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