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J Arenas

Publications and source records attributed to J Arenas.

At least 127 records · Page 7Linked to original sources
PubMed1997

Syndrome of encephalopathy, petechiae, and ethylmalonic aciduria.

We report a boy 20 months of age with encephalopathy, petechiae, and ethylmalonic aciduria (EPEMA). Other clinical features were severe hypotonia, orthostatic acrocyanosis, and chronic diarrhea. Magnetic resonance imaging (MRI) of the brain demonstrated bilateral lesions in the lenticular and caudate nuclei, periaqueductal region, subcortical areas, white matter, and brainstem. Short and medium chain Acyl-CoA dehydrogenase and cytochrome c oxidase (COX) activities in fibroblasts were normal. Muscle histochemistry disclosed diffuse COX deficiency, and respiratory chain activities in muscle disclosed severe COX deficiency. Twelve other patients with similar clinical features have been reported. Muscle COX activity, studied only in four, demonstrated a clear-cut defect.

Brain↗
PubMed1997

Association of genetically proven deficiencies of myophosphorylase and AMP deaminase: a second case of 'double trouble'.

We studied a 25-year-old man with paresis of the limbs and neck, scapular atrophy, facial weakness, exercise intolerance and frequent episodes of myoglobinuria. Muscle histochemistry and biochemistry revealed a combined defect of myophosphorylase and AMP deaminase. Molecular genetic analysis showed that the patient was homozygous for the two most common mutations associated with myophosphorylase and AMP deaminase deficiencies. This is the second documented case of genetic 'double trouble', which should be looked for in patients with unusual severe phenotypes.

AMP Deaminase↗
PubMed1997

Diffuse fatty liver in familial heterozygous hypobetalipoproteinemia.

A 34-year-old man had asymptomatic hepatomegaly, slightly increased serum alanine aminotransferase and gamma-glutamyl transpeptidase levels, and a sonographic pattern suggesting diffuse hepatic steatosis. Liver biopsy revealed fatty change in 25% to 50% of hepatocytes. The patient also had low serum levels of cholesterol and triglycerides and met clinical, biochemical, and familial diagnostic criteria of heterozygous hypobetalipoproteinemia. We could not relate his hepatic steatosis to any already known cause of fatty liver and could only attribute it to heterozygous hypobetalipoproteinemia. Familial heterozygous hypobetalipoproteinemia should be ruled out in patients with unexplained hepatic steatosis.

Adult↗
PubMed1997

Gene dosage effect in one family with myoclonic epilepsy and ragged-red fibers (MERRF).

OBJECTIVES: We analyzed the percentage of mitochondrial DNA (mtDNA) heteroplasmy in blood samples of 13 individuals belonging to a three family generation of myoclonic epilepsy with ragged-red fibers (MERRF) and compared the 5 affected patients and the 8 unaffected relatives. MATERIAL AND METHODS: DNA was extracted from blood and muscle of the proband and from blood of 12 maternal relatives. A PCR restriction analysis method was used to detect the mutation. RESULTS: The proband had the complete MERRF phenotype. The phenotype in three other individuals in the maternal lineage was consistent with the MERRF syndrome. The remaining were asymptomatic. The np 8344 mutation was observed in muscle and blood of the proband, and in blood from every one of 12 maternal relatives, ranging from 44% to 83% of mutated genomes. Symptomatic individuals had higher levels (P < 0.001) of mutated mtDNA than asymptomatic maternal relatives. However, high proportions of mutant genomes (up to 63%) were found in asymptomatic relatives. CONCLUSIONS: Although there seems to be a gene dosage effect in MERRF, we found no absolute relationship between the relative proportion of mutant genomes in blood and clinical severity. Factors other than gene dosage in blood may account for the differences in clinical phenotype.

Adult↗
PubMed1997

Respiratory chain enzyme activities in isolated mitochondria of lymphocytes from patients with Alzheimer's disease.

We studied respiratory chain enzyme activities in lymphocyte mitochondria from 33 patients with Alzheimer's disease (AD) and from 30 age- and sex-matched healthy controls. The respiratory chain enzyme activities did not differ significantly between patients and controls. No patient showed any value for respiratory chain enzyme levels below normal range. Values for activities of complexes in the AD group did not correlate with age at onset or duration of the disease. Our finding of normal mitochondrial function in lymphocyte mitochondria suggests that this tissue cannot be used to demonstrate the involvement of oxidative phosphorylation in AD and, thus, to develop a diagnostic test for AD.

Aged↗
PubMed1997

Leigh syndrome associated with the T9176C mutation in the ATPase 6 gene of mitochondrial DNA.

A child with clinical and neuroradiologic evidence of Leigh syndrome (LS) had the T-to-C transition at nt 9176 in the ATPase 6 gene of mtDNA. The mutation was homoplasmic in muscle and maternally inherited. The proband's mother had ataxia and harbored 93% of mutant genomes in blood, whereas three clinically unaffected maternal relatives had varying degrees of heteroplasmy in blood. These data confirm the association of the T9176C mutation with LS and extend the clinical heterogeneity of mutations in the ATPase 6 gene.

Adenosine Triphosphatases↗
PubMed1996

Neurotransmitter amino acids in cerebrospinal fluid of patients with Parkinson's disease.

We measured the CSF and plasma levels of glutamate, glutamine, aspartate (only in plasma), asparagine, glutamine, glycine and GABA in 31 patients with Parkinson's disease and in 45 matched controls. We used an ion-exchange chromatography method. When compared to controls, PD patients had similar CSF levels of glutamate, glutamine, asparagine, and glycine higher CSF GABA levels higher plasma levels of glutamine, asparagine, and glycine, and lower plasma levels of aspartate. The CSF levels of the amino acids measured were not correlated with the clinical features of PD. Our results that CSF GABA levels are not decreased in PD as previously suggested.

Aged↗
PubMed1996

Maya Blue Paint: An Ancient Nanostructured Material

Maya blue paint was often used in Mesoamerica. The origin of its color and its resistance to acids and biocorrosion have not been fully understood. High-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray microanalysis studies of authentic samples show that palygorskite crystals in the paint form a superlattice that probably occurs as a result of mixing with indigo molecules. An amorphous silicate substrate contains inclusions of metal nanoparticles encapsulated in the substrate and oxide nanoparticles on the surface. The beautiful tone of the color is obtained only when both the particles and the superlattice are present.

Journal Article↗
PubMed1996

Reduced carnitine palmitoyl transferase activity and altered acyl-trafficking in red blood cells from hemodialysis patients.

We measured carnitine palmitoyl transferase activity, free carnitine, and long chain acyl carnitine levels in erythrocytes from 15 uremic patients and 25 controls. Carnitine palmitoyl transferase levels in patients were significantly lower than in controls. The levels of free carnitine and long chain acyl carnitines as well as the long chain acyl carnitine/free carnitine ratio were significantly higher in patients than in controls. Our results suggest that hemodialysis causes alteration in the acyl-trafficking in red blood cells membrane.

Adult↗
PubMed1996

Sporadic MERRF/MELAS overlap syndrome associated with the 3243 tRNA(Leu(UUR)) mutation of mitochondrial DNA.

We studied a patient with a mitochondrial encephalomyopathy characterized by the presence of all the cardinal features of both myoclonic epilepsy and ragged-red fibers (MERRF) and mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes (MELAS) syndromes. Muscle biopsy showed ragged-red fibers (RRF). Some RRF were cytochrome c oxidase (COX)-negative while some others stained positive for COX. Muscle biochemistry revealed defects of complexes I and IV of the respiratory chain. Both muscle and blood mitochondrial DNA from the patient showed the presence of the mutation at nucleotide position 3243 in the tRNA(Leu(UUR)) gene and the absence of point mutations related to MERRF syndrome. The proportions of mutant mtDNA were 70% in muscle and 30% in blood. The mutation was absent in blood from all maternal relatives, in hair follicles from the mother, and in muscle from one sister of the proband. Therefore, there was no evidence of maternal inheritance.

Adolescent↗
PubMed1996

Abnormal carnitine distribution in the muscles of patients with idiopathic inflammatory myopathy.

OBJECTIVE: To analyze the levels of free carnitine and carnitine esters in the muscles of patients with inflammatory myopathies. METHODS: Six men and 7 women with inflammatory myopathy and 25 age-matched healthy controls were studied. Free carnitine and carnitine esters in muscle homogenates were measured by a radiochemical procedure. Muscle histochemical staining and measurement of respiratory chain enzyme activity were also performed. RESULTS: Eleven patients had muscle carnitine insufficiency. Five of them had subsarcolemmal oxidative accumulations, 5 had lipid droplets, and 4 had defects of the respiratory chain enzyme complexes. CONCLUSION: Abnormal distribution of muscle carnitine is present in patients with inflammatory myopathies and could impair muscle function. Coexistent mitochondrial dysfunction may contribute to carnitine insufficiency.

Adolescent↗
PubMed1996

Relationship of curative surgery on natural killer cell activity in colorectal cancer.

PURPOSE: Aim of this study has been to evaluate natural killer (NK) activity in patients with colorectal tumors before and after curative surgery. METHODS: Forty colorectal cancer patients without distant metastases were stratified according to American Joint Committee on Cancer/International Union Against Cancer staging system into three categories: Stage I (n = 12), Stage II (n = 15), and Stage III (n = 13). All of them underwent curative resection, and there were no major postoperative complications. Venous blood samples were obtained preoperatively, at surgical wound closure, and on the 1st, 7th, and 21st postoperative days. Mononuclear cells were isolated over Ficoll-Hypaque (Lymphoprep, Nycomed Pharma AS, Oslo, Norway) gradients, and NK activity was assayed by evaluation of cytotoxic response against K562 cells. Normal NK activity was achieved from 15 healthy donors. Percentage relative increments in relation to preoperative levels were calculated for every postoperative sample, and t-test was used for statistical evaluation. RESULTS: Before surgery, Stages II and III patients had lower levels of NK activity than healthy people (P < 0.05 and P < 0.001, respectively). NK activity always fell after surgery (Stage I: -18.48 +/- 11.42; Stage II: -16.93 +/- 13.57; Stage III: -35.29 +/- 12.03, at day 1 postsurgery) and appeared to rise slightly by the 21st postoperative day in Stage I patients (+4.87 +/- 12.41). Stage II, and especially Stage III, patients did show a significant recovery by the 21st postoperative day (+23.63 +/- 9.36 and +43.19 +/- 13.34, respectively). At this time, NK activity in these two groups was not significantly lower than in normal subjects (P > 0.05). CONCLUSION: NK activity is depressed in colorectal cancer patients in relation to progression of illness, even at locoregional stages. Curative resection of tumors at Stages II and III has promoted a recovery of NK activity in patients with uneventful postoperative courses.

Aged↗
PubMed1996

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

It has been suggested that nitric oxide could be implicated in the pathogenesis of Alzheimer's disease (AD). Recently Kuiper et al. reported decreased CSF nitrate levels (oxidation product that provides an indirect estimation of nitric oxide) in AD patients, assessed with a colorimetric method. However other group, using a microplate version of the Griess reaction, did not confirm these findings. We studied the CSF and plasma levels of nitrate with kinetic cadmium-reduction method in 32 AD patients and 36 matched controls. The CSF and plasma nitrate levels did not differ significantly between the two study groups. CSF and plasma nitrate levels did not correlate with age at onset and duration in the patient group. These data suggest that CSF and plasma levels of nitrate are apparently unrelated with the risk for AD.

Aged↗