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Biomedical subjects

M Martinez

Publications and source records attributed to M Martinez.

At least 235 records · Page 13Linked to original sources
PubMed1993

Ultrastructural study of the ventral lobe of the prostate of rats submitted to experimental chronic alcoholism.

The effects of chronic alcohol ingestion on the ventral lobe of the prostate were studied in rats (Rattus norvegicus). Ultrastructural observations on the epithelial cells of the ventral lobe of the prostate showed irregularly shaped nuclei with deep infoldings, dilated RER cisternae, and a small number of microvilli covering the cell surface. After 90 and 135 days of alcohol treatment, the epithelial cells showed signs of degeneration.

Alcoholism↗
PubMed1993

Stimulation of human somatosensory cortex: tactile and body displacement perceptions in medial regions.

We examined the somatosensory perceptions evoked by stimulation of rolandic and parietal brain regions in 40 epileptic patients undergoing a presurgical investigation with intracerebral electrodes. Bipolar stimulation trains were delivered in an incremental sequence at medial and/or lateral contact pairs of stereotaxically implanted, multi-contact electrodes, while monitoring stimulus after discharge propagation with electrodes in frontal and temporal lobes. Rolandic stimulation evoked contralateral sensations, whereas sensations from either side were evoked in the opercular region. Stimulation of lateral posterior parietal cortex evoked only few sensations and these were restricted to the supramarginal gyrus. Contralateral sensations were evoked in the posterior cingulate gyrus, whereas ipsilateral sensations were evoked in the vicinity of the cingulate sulcus. Complex proprioceptive sensations in the form of bilateral feelings of levitation were elicited in a medial parietal region around the subparietal sulcus and not at any other site. These perceptions were not accompanied by any movement, tactile, or vestibular sensations, suggesting that the human sub-parietal sulcus region is linked to the proprioceptive processing system.

Electrodes↗
PubMed1993

Amino acid concentrations in cerebrospinal fluid and serum in Alzheimer's disease and vascular dementia.

Cerebrospinal fluid (CSF) and serum levels of 22 amino acids were studied in 13 patients with dementia of the Alzheimer type (DAT), 13 patients with vascular dementia (VD) and 15 age-matched controls. We found significantly reduced levels of glutamate in CSF samples from DAT patients compared to VD and control subjects, but CSF levels of aspartate were found to be significantly elevated in the two groups of dementia studied. Moreover, CSF concentrations of tyrosine, leucine and phenylalanine were significantly increased in VD patients in comparison with those in DAT patients and control subjects. Our results showed a wide increase in CSF/serum amino acid ratios in DAT and VD groups compared to controls. However, no differences were found in CSF/serum ratios between dementia groups. These changes show evidence for a possible disorder of amino acid metabolism with different patterns in these two dementia types.

Aged↗
PubMed1993

Altered cerebrospinal fluid amino acid pattern in the anorexia of aging: relationship with biogenic amine metabolism.

To study the possible role of several amino acids on feeding in the anorexia of aging, we have measured plasma and cerebrospinal fluid (CSF) concentrations of 22 amino acids in 14 elderly persons with idiopathic anorexia and 10 healthy subjects with normal weight in a similar age range. Plasma and CSF amino acid concentrations and CSF homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) levels were all measured by HPLC methods. Elderly anorectic subjects had significantly lower levels of glutamic acid but increased concentrations of glutamine in both plasma and CSF compared to controls. Likewise, a significant increase of histidine, threonine, alanine, arginine, valine, methionine, isoleucine, leucine, phenylalanine, tryptophan, ornithine and lysine was found in CSF, but not in plasma, from patients with anorexia. Besides, the CSF histidine/LNAA (large neutral amino acids) and tryptophan/LNAA ratios were elevated in anorectic patients as compared with controls of similar age. In addition, we found higher CSF concentrations of HVA and 5-HIAA, as well as a positive correlation between CSF LNAA and either HVA (r = 0.74, p = 0.002) or 5-HIAA (r = 0.61, p = 0.020) concentrations in elderly anorectics. CSF tryptophan correlated positively with 5-HIAA levels (r = 0.59, p = 0.026) and CSF tyrosine with HVA levels (r = 0.77, p = 0.002). Our results suggest that changes in the CSF concentration of amino acids could contribute to an increased biogenic amine metabolism in the central nervous system of elderly anorectic subjects, possibly increasing the synaptic liberation of biogenic amines involved in the appetite regulation.

Aged↗
PubMed1993

Linkage analysis of fifty-seven microsatellite loci to bipolar disorder.

The authors' goal was to screen for genetic linkage with highly informative deoxyribonucleic acid (DNA) microsatellite markers on a series of moderately sized North American bipolar disorder (BP) pedigrees. These BP pedigrees were genotyped with 57 short tandem-repeat polymorphic systems (microsatellites) that were enzymatically amplified from genomic DNA. We did not find significant evidence for genetic linkage. We found isolated LOD scores greater than 2 on chromosome 1 at two loci in individual pedigrees. Simulation studies for multiple analyses under the assumptions of linkage and nonlinkage were performed. The simulations show that LOD scores greater than 2 could be expected even when linkage is absent. Significance levels need to be considered carefully in systematic linkage studies.

Bipolar Disorder↗
PubMed1993

Docosahexaenoic acid--a new therapeutic approach to peroxisomal-disorder patients: experience with two cases.

Docosahexaenoic acid (DHA, 22:6 omega 3) is a major constituent of brain membrane phospholipids and photoreceptor cells. Patients with generalized peroxisomal disorders have extremely low levels of DHA in the brain and other tissues. Since a DHA deficiency could explain some basic symptoms in peroxisomal-disorder patients, we tested the possible beneficial effects of DHA in two patients with neonatal adrenoleukodystrophy (NALD). Before the treatment, both patients had very low DHA levels in plasma and erythrocytes. We first gave DHA in the form of fish oil and, in both patients, the rapid increase in red-cell DHA levels indicated that this fatty acid was being absorbed and incorporated into membrane phospholipids very fast. However, a low ratio 22:6 omega 3/22:5 omega 3 was still present in erythrocyte membranes, and the content of 20:5 omega 3 (eicosapentaenoic acid) was too high with the fish oil diet. We then began treatment with pure DHA ethyl ester and, after a few weeks, erythrocyte omega 3 polyunsaturated fatty acids were normal. There was an increase in the 18:0 molecular species of plasmalogens in both patients, most significantly in the child with affected plasmalogen biosynthesis in cultured fibroblasts. In the less severely affected NALD patient, treatment with DHA produced a very significant decrease in the ratios 24:1/22:0 and 26:1/22:0, and this child improved neurologically. The present data suggest that DHA deficiency may be the cause for some of the most characteristic abnormalities in peroxisomal-disorder patients and open new therapeutic possibilities for these patients.

Child↗
PubMed1993

Head and neck manifestations of sarcoidosis.

Sarcoidosis is a multisystem granulomatous disease of unknown etiology affecting young adults and presenting most commonly with bilateral hilar lymphadenopathy, pulmonary infiltrates, and skin or eye lesions. The manifestations of this disease are protean and its clinical course is variable. Often the mode of onset correlates with the natural course and prognosis of the disease. Acute onset usually leads to remission within 12 to 18 months. Insidious, chronic disease often results in fibrotic sequelae. The treatment of choice for sarcoidosis is systemic corticosteroids.

Adrenal Cortex Hormones↗
PubMed1993

[Genetic markers and risk factors in diseases with complex etiology: psychiatric diseases].

The goal of this paper is to show how the information provided by genetic markers may help to delineate the genetic factors implicated in the aetiology of mental disorders. Family studies have provided good evidence for the involvement of genetic factors in the aetiology of two of the most common psychiatric diseases: affective disorders and schizophrenia. However, a single susceptibility gene responsible for all the familial resemblance for these diseases is unlikely. Analysis of the disease transmission in families has been, so far, unsuccessful in delineating a genetic component in their aetiology. With the recent development of molecular genetics a large number of genetic markers are now available. They allow an alternative investigation of the genetic aetiology of such disease. Indeed a non independent transmission of the disease is evidence for 1) the effect of at least one susceptibility gene and 2) the genetic localization of this gene on the same chromosome and near the marker. However, linkage strategies in psychiatric disorders face specific difficulties that should not be ignored. For such complex diseases, the observed disease correlations between relatives are likely due to the effect and to the interaction of both genetic and non genetic factors. Accurate analysis of genetic linkage requires consideration of residual (non-genetic) familial correlations in the joint segregation of the disease and the marker. Furthermore, focusing linkage strategies on markers of candidate genes would clearly enhance the power of the linkage test.

Bipolar Disorder↗
PubMed1992

Abnormal profiles of polyunsaturated fatty acids in the brain, liver, kidney and retina of patients with peroxisomal disorders.

The polyunsaturated fatty acid (PUFA) composition of the brain was studied in 8 patients with Zellweger's syndrome (ZS), 3 with neonatal adrenoleukodystrophy (NALD), one with bifunctional enzyme deficiency (BED), one with X-linked adrenoleukodystrophy (X-ALD), and one with adrenomyeloneuropathy (AMN). The PUFA composition of the liver, kidney and retina was studied in 8, 6 and 1 patients with ZS, respectively. An infant with NALD and a child with rhizomelic chondrodysplasia punctata (RCDP) were also studied for the PUFA composition of the liver. The liver and kidney of the patient with X-ALD and the liver of the patient with AMN were included in the study. The fatty acid values in the peroxisomal patients were compared with control data obtained in the normal developing brain (38 cases), liver (9 cases), kidney (7 cases) and retina (16 cases). The brain of a patient with metachromatic leukodystrophy (MLD) and the liver of a child with Krabbe's disease (KD) were also studied for comparison. The most constant and severe abnormality in all the peroxisomal patients was a drastic decrease in the total amount of docosahexaenoic acid (22:6 omega 3), especially in the brain. The other product of delta 4-desaturation, 22:5 omega 6, was generally decreased in the brain, liver and kidney of the ZS patients, but very much increased in the brain of two patients with NALD. The 22:6 omega 3/22:4 omega 6 ratio, which remains quite constant throughout normal brain development, was consistently decreased in the peroxisomal brain, in ZS as well as in NALD. This study confirms that, in classical Zellweger's syndrome, the two products of delta 4-desaturation are affected. In contrast, in neonatal adrenoleukodystrophy the deficiency is probably restricted to the omega 3 product of delta 4-desaturation, docosahexaenoic acid, especially in the brain, while the other product, 22:5 omega 6, is either normal or increased, perhaps in an attempt to compensate for the 22:6 omega 3 deficiency in brain membranes.

Adolescent↗
PubMed1992

Variation in the antigenic characteristics of venom from the Mojave rattlesnake (Crotalus scutulatus scutulatus).

Venoms from 31 specimens of the Mojave rattlesnake (Crotalus scutulatus scutulatus) were examined to further characterize reported differences among venoms of this species. Twenty-two venoms were recognized by a monoclonal antibody to Mojave toxin, CSS12. Nine venoms were recognized by CA-P-8, a monoclonal antibody produced against the hemorrhagic venom of C. atrox. Seven of these produced strong hemorrhage in mice and were also recognized by polyclonal antibodies (anti-F5) produced against a fraction of Mojave rattlesnake venom that inactivates serum complement. Fractionated venom revealed that CA-P-8 and anti-F5 recognized different proteins. Two of the venoms recognized by CA-P-8 were not recognized by anti-F5 and produced minimal hemorrhage in mice. This suggests that more than one factor may be necessary to induce strong hemorrhage.

Animals↗
PubMed1992

Porcine epidemic abortion and respiratory syndrome (mystery swine disease). Isolation in Spain of the causative agent and experimental reproduction of the disease.

In March of 1991, a disease that affected pregnant sows and caused a high mortality in unweaned piglets was detected in Spain. Based on the clinical signs observed, mystery swine disease, which had been described recently in Germany, Holland and Belgium, was suspected. From the samples obtained from the affected farm, a filtrable agent (0.22 micron) was isolated on cell culture. It produced cytopathic effects, its replication was intracytoplasmic, it was sensitive to chloroform, and cross-reacted with a Lelystad reference serum. When inoculated into pregnant sows, the agent produced inappetence for 2-4 days, without hyperthermia. One of the sows aborted at 100 days of gestation; the two others had delayed parturitions (days 115 and 116). There was a mixture of healthy piglets, mummified fetuses, stillbirths and weak piglets. Microscopic examination of the lungs of healthy piglets killed at 8 and 12 days of life revealed the presence of interstitial pneumonia. The sera from the three sows at 39 days after infection cross-reacted with the Lelystad virus (titres > or = 1/640), whereas pre-inoculation sera did not recognize it (titres < or = 1/10). This is the first report from Spain of the isolation of an agent (antigenically related to the Lelystad virus), capable of reproducing the disease previously designated as mystery swine disease.

Animals↗
PubMed1992

Tissue levels of polyunsaturated fatty acids during early human development.

Long-chain fatty acids are analyzed in tissues from infants whose cause of death was not neurologically related. Total n-3 and n-6 polyunsaturated and n-9 monounsaturated fatty acid amounts increased in the whole forebrain during the prenatal and postnatal periods up to at least 2 years of age. The most abundant brain polyunsaturated fatty acids were docosahexaenoic acid (DHA) (22:6n-3), arachidonic acid (AA) (20:4n-6), and adrenic acid (22:4n-6). In neonates receiving total parenteral nutrition for several days, the DHA/AA ratio was outside the normal range in the liver but within the normal range in the brain. Two other children received total parenteral nutrition for many months, but only the one born at 29 weeks of gestation had a low brain DHA/AA ratio. Another infant, born at 25 weeks of gestation, had been fed milk formulas containing high linoleate/alpha-linolenate ratios for 4 months. This infant had less DHA and a lower DHA/AA ratio in both the brain and the retina than had term infants. These data suggest that preterm infants are especially at risk for the effects of dietary fatty acid imbalances.

Arachidonic Acid↗