Search PubMed⌕ Search

Biomedical subjects

J Arenas

Publications and source records attributed to J Arenas.

195 records · Page 11Linked to original sources
PubMedDate not supplied

Cerebrospinal fluid nitrate levels in patients with Parkinson's disease.

It has been suggested that nitric oxide could be implicated in the neuronal degeneration of substantia nigra compacta in patients with Parkinson's disease. Recently, it has been reported decreased CSF nitrate levels (oxidation product that provides an indirect estimation of nitric oxide) in Parkinson's disease patients, assessed with a colorimetric method. We studied the CSF and plasma levels of nitrate with a kinetic cadmium-reduction method in 31 Parkinson's disease patients and 38 matched controls. The CSF and plasma nitrate levels were not correlated either in patient or in the control group, and they did not differ significantly between the two study groups. They were not influenced significantly by antiparkinsonian drugs in patients, although there was a trend for CSF nitrate levels to be higher in patients treated with levodopa or with dopamine agonists. CSF and plasma nitrate levels did not correlate with age at onset, duration, scores of the unified Parkinson's disease rating scales and Hoehn & Yahr staging in the patients group. These date suggest that CSF and plasma levels of nitrate are apparently unrelated with the risk for PD.

Blood-Brain Barrier↗
PubMedDate not supplied

Ecological aspects of nematode parasites of introduced salmonids from Valdivia river basin, Chile.

Between 1986 and 1987, 666 fishes distributed among the following species introduced in Chile, and from different sectors of the Valdivia river basin (39 degrees 30'-40 degrees 00'S, 73 degrees 30'-71 degrees 45'W), were examined: 348 Salmo trutta, 242 Salmo gairdneri, 24 Cyprinus carpio and 52 Gambusia affinis holbrooki. The presence of Camallanus corderoi and Contracaecum sp. in S. gairdneri and of C. corderoi in S. trutta is recorded in Chile for the first time. Cyprinus carpio and G. a. holbrooki did not present infections by nematodes. The prevalence and mean intensity of the infections by nematodes presented significant differences among some sectors of the Valdivia river basin. In general, the prevalence and intensity of the infections by C. corderoi were greater than those by Contracaecum sp. The infections in S. gairdneri were higher than in S. trutta. The sex of the hosts had no influence on the prevalence and intensity of the infections by both nematodes. The length of the hosts did have an influence, except in the case of the infections by Contracaecum sp. in S. gairdneri. The infrapopulations of both nematode species showed over-dispersion in most cases. The diet of the examined salmonids suggests that they would become infected principally through the consumption of autochthonous fishes.

Animals↗
PubMedDate not supplied

[Early mitochondrial encephalomyopathy due to complex IV deficiency consistent with Alpers-Huttenlocher syndrome: report of two cases].

INTRODUCTION: Complex IV or cytochrome c oxidase (COX) deficiency is the most common disorder involving complexes of the respiratory chain in the pediatric age. Exceptionally, it has been reported in association with Alpers syndrome or Alpers disease, and with its variant named progressive neuronal degeneration with liver disease or Alpers-Huttenlocher syndrome. OBJECTIVE: To report the cases of two infants with mitochondrial encephalomyopathy due to COX deficiency in whom the clinical, biochemical, neurophysiologic and neuroimaging characterization suggested an associated Alpers-Huttenlocher syndrome. CLINICAL CASES: Two no-related males, one with noncontributory family history and the other with third-grade consanguineous parents developed refractory seizures from age 20 and 60 days, respectively. Additionally, myoclonic fits accounted on evolution of the condition. In the first case, serial EEG recordings showed low amplitude polyspikes, polyspike waves and very slow waves of high amplitude alternating with a trace of burst-suppression activity. In the second case, a right preponderant but also bilateral low amplitude polyspikes, polyspike waves and occasional desynchronization of basal trace were recorded. In both, a rapidly progressive cerebral atrophy, neurological deterioration with pyramidal signs, and tendency to microcephaly, ensued. Accompanying to this clinical picture, minor hepatic dysfunction, elevated protein levels in the CSF, lactic acidosis and COX deficiency in muscle homogenate were demonstrated. In the first case, moreover, cortical blindness and severe hepatic failure occurred while receiving valproate, in spite of concomitant L-carnitine therapy. CONCLUSIONS: We believe that the reported cases are consisted with Alpers-Huttenlocher syndrome associated with mitochondrial encephalomyopathy due to COX deficiency. Nevertheless, early myoclonic encephalopathy, a condition related in same cases with poliodistrophy, must be keep in mind as a possible diagnosis in case 1.

Anticonvulsants↗
PubMedDate not supplied

[Mitochondrial encephalopathies].

OBJECTIVE: We carry out a review of the current basic genetic, biochemical, clinical, diagnostic and therapeutic aspects of mitochondrial cytopathies due to deficiencies in the mitochondrial respiratory chain complexes, which appear clinically during childhood and/or adolescence. DEVELOPMENT: The clinical description has been divided into two groups: mitochondrial cytopathies secondary to alterations of mitochondrial DNA (mtDNA) and mitochondrial cytopathies secondary to alterations of the nuclear DNA (nDNA); we also consider about the importance of such conditions at this age.

Brain↗
PubMedDate not supplied

[Sporadic familial meningiomas].

INTRODUCTION: Meningiomas are primary tumours of the central nervous system. Usually they are sporadic. The occurrence in more than one member of a family is unusual. Up till now this coincidence had been related with type 2 neurofibromatosis. In this paper we comment on two siblings who did not fulfil neurofibromatosis diagnostic criteria as an example of sporadic familial meningiomas. CLINICAL CASES: Two siblings (a 79 years old female and a 77 years old male) were diagnosed of a meningioma in an interval of two years, with surprising clinical and neuroimaging similarities. In sporadic meningiomas, abnormalities in the long arm of chromosome 22 have been found. Type 2 neurofibromatosis causative gene has also been found in this chromosome. Meningiomas are quite often found in this entity, and therefore, this gene was implicated as a main factor in the genesis of an important number of meningiomas. However, several studies have not found an association between these tumours and the locus for neurofibromatosis, leading to think that there may be other genes that may influence on meningiomas development.

Aged↗
PubMedDate not supplied

[Benign congenital myopathy associated with a partial deficiency of complexes I and III of the mitochondrial respiratory chain]].

INTRODUCTION: Isolated or combined enzyme deficiencies of the mitochondrial respiratory chain results in a number of clinical heterogeneous conditions. When presented in the neonatal period or early in the infancy the course is usually severe, although isolated cases with benign evolution have also been described. OBJECTIVE: To describe the clinical and biochemical characteristics of a child with a benign form of mitochondrial myopathy due to a combined deficiency of the complexes I and III of the respiratory chain. CLINICAL CASE: A 40 days-old male, the second son of a young non-consanguineous couple, presented with axial congenital hypotonia, asymmetrical macrocephaly, mild enlargement of the liver, mild coarsening of facial features, increased CK serum values, persistently elevation of serum lactate and lactate/pyruvate ratio and external hydrocephalus. Electromyogram and histological muscle examination were normal but analysis of the respiratory chain disclosed a deficiency of the complexes I and III. From 13 months-age onwards clinical detailed abnormalities progressively ameliorated and also did it serum CK, lactate and external hydrocephalus. CONCLUSION: We think that on clinical, basic biochemical and histological grounds there are some similarities between this case of congenital unspecific myopathy and benign reversible form of mitochondrial myopathy, arguing in favor of a possible relationship between both conditions.

Electron Transport Complex III↗
PubMedDate not supplied

[Multiple symmetrical lipomatosis with familial polineuropathy].

INTRODUCTION: Multiple symmetrical lipomatosis (LSM) is characterized by the development of symmetrical lipomas and is often associated with axonal polyneuropathy (PNP). Presentation is usually sporadic. Familial cases have been reported infrequently, with variable modes of inheritance. The pathogenesis is unknown. It has been related to mitochondrial cytopathy and alterations in lipid metabolism. OBJECTIVES: To establish clinico pathological correlation in our cases of familial presentation. Patients and methods. We report seven patients, from three families, teetotalers with LSM. Clinical assessment included lipidogram, neurophysiological study of nerve and muscle, sural nerve biopsy in two of them and muscle biopsy in one member of each family for morphological assessment, respiratory chain biochemistry and study of molecular genetics. RESULTS: LSM was associated with axonal PNP and hyperlipidemia in the seven members of the three families, with an apparent pattern of autosomal recessive inheritance. No conclusive data of mitochondrial cytopathy, in the form of significant morphological changes, biochemistry of the mitochondrial respiratory chain or micochondrial DNA were found. CONCLUSION: Although mitochondrial cytopathy has been described as part of the syndromes in which LSM occurs, there may be other undefined aspects, such as disorders of lipid metabolism which form part of the pathogenesis.

Aged↗
PubMedDate not supplied

[Molecular genetics of disorders of the mitochondrial respiratory chain].

Mitochondria have a key role in cell metabolism, being the major site of ATP production via oxidative phosphorylation. This system consists of five multiprotein complexes, whose individuals subunits are encoded either by the mitochondrial or by the nuclear genome. Respiratory chain enzyme deficiencies result in devastating, usually multisystem, disorders. Recently, many underlying mutations in mitochondrial and nuclear genes have been described at a brisk pace as a result of the advances in the knowledge of molecular genetics.

DNA, Mitochondrial↗
PubMedDate not supplied

[Multiple symmetric lipomatosis associated to polyneuropathology, atrophy of the cerebellum and mitochondrial cytopathy].

INTRODUCTION: Multiple symmetric lipomatosis (MSL), which is predominantly found in middle aged males, is characterised by accumulations of fat in the neck, shoulders and other parts of the trunk, and sometimes associated with different neurological manifestations, both central and peripheral. Although its aetiology is unknown, it has been described as associated with mitochondrial cytopathies. AIMS. To describe the case of a young female with MSL associated with mitochondrial encephalomyopathy. CASE REPORT: Girl aged 14 with MSL, ataxia, patellar hyperreflexia, bilateral Babinski sign, pes cavus, axonal peripheral neuropathy, involvement of the optic pathway, atrophy of the cerebellum, subsarcolemmal mitochondrial accumulations in the untrastructural examination of the vastus lateralis muscle and partial deficit of complex I in the mitochondrial respiratory chain. As regards molecular genetic aspects, the most frequent mutations of the ATPase 6 gene in lymphocytes, and mtDNA deletions and tRNALys and tRNALeu(UUR) mutations in muscles were excluded. CONCLUSIONS: Despite the fact that MSL is an entity normally found in adults, the possibility of its being diagnosed in the paediatric age must be taken into account. This case is probably the second time MSL has been observed associated with mitochondrial cytopathy in this age bracket.

Adolescent↗
PubMedDate not supplied

[Metabolic intolerance to exercise].

Exercise intolerance (EI) is a frequent cause of medical attention, although it is sometimes difficult to come to a final diagnosis. However, there is a group of patients in whom EI is due to a metabolic dysfunction. McArdle's disease (type V glucogenosis) is due to myophosphorylase (MPL) deficiency. The ischemic exercise test shows a flat lactate curve. The most frequent mutations in the PYGM gene (MPL gene) in Spanish patients with MPL deficiency are R49X and W797R. Carnitine palmitoyltransferase (CPT) II deficiency is invariably associated to repetitive episodes of myoglobinuria triggered by exercise, cold, fever or fasting. The diagnosis depends on the demonstration of CPT II deficiency in muscle. The most frequent mutation in the CPT2 gene is the S113L. Patients with muscle adenylate deaminase deficiency usually show either a mild myopathy or no symptom. The diagnosis is based on the absence of enzyme activity in muscle and the lack of rise of ammonia in the forearm ischemic exercise test. The mutation Q12X in the AMPD1 gene is strongly associated with the disease. Exercise intolerance is a common complaint in patients with mitochondrial respiratory chain (MRC) deficiencies, although it is often overshadowed by other symptoms and signs. Only recently we have come to appreciate that exercise intolerance can be the sole presentation of defects in the mtDNA, particularly in complex I, complex III, complex IV, or in some tRNAs. In addition, myoglobinuria can be observed in patients under statin treatment, particularly if associated with fibrates, due to an alteration in the assembly of the complex IV of the MRC.

Adenosine Deaminase↗
PubMedDate not supplied

[Complex I and IV deficits in the mitochondrial respiratory chain in two siblings with type I glutaric aciduria].

We report two brothers with a glutaric aciduria type I (GA-I) identified by Glutaryl-coenzyme A dehydrogenase deficiency in skin fibroblasts. The onset of neurologic abnormalities was at 6 and 9 months of age as an acute Reye-like presentation in one. Because of the hyperlactacidemia, hyperlactatorrachia, mitochondrial abnormalities in muscular cells and a deficiency in complex I and IV of the respiratory chain in isolated mitochondria from muscle, a presumptive diagnosis of Leigh syndrome was made. We analyze the difference between both disorders. GA-I should be suspected in patients with acute dystonia and psychomotor regression, lactic acidosis and hypodensity of the basal ganglia.

Brain↗