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Biomedical subjects

M Martinez

Publications and source records attributed to M Martinez.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Isolation of a fibrinolytic protease, M4, from venom of Crotalus molossus molossus (northern blacktail rattlesnake).

M4, a fibrinolytic protease, was isolated from the venom of Crotalus molossus molossus. It has a pI of 9.6 and a molecular weight of 27,000. The protease hydrolyzes the A alpha and B beta chains of fibrinogen, and the alpha and beta chains of fibrin. This activity was inhibited by EDTA and restored by Ca2+ or Zn2+, but not Mg2+. The protease hydrolyzed hide power azure and casein, but it had no effect on collagen, hyaluronic acid, complement or synthetic substrates for thrombin, plasmin or kallikrein. Subcutaneous injections into mice with doses as high as 100 micrograms did not cause hemorrhage. This protease may have therapeutic use as a thrombolytic agent.

Amino Acid Sequence↗
PubMed1992

A systematic search for a bipolar predisposing locus on chromosome 5.

Chromosome 5 markers spanning the pter to the qter were used to examine linkage to bipolar illness in 14 pedigrees. Twenty-four loci were examined in 237 individuals, of whom 69 were either bipolars or schizoaffectives. Marker genotypes were determined for each individual and lod scores were calculated under a dominant disease model with a maximum penetrance of 85%, a disease gene frequency of 0.015, a variable age of onset, and a phenocopy rate of 0.001. Under the assumption that bipolar illness is genetically homogeneous, the total lod scores from all pedigrees with each marker were uniformly lower than -2.0, suggesting the absence of linkage to disease at any of these loci. Multipoint analysis allowed exclusion of intervals between markers. When lod scores were calculated allowing for heterogeneity, no subset of linked families was found. These results indicate that in our pedigree series almost the entire mapped region of chromosome 5 can be excluded for linkage to bipolar illness.

Bipolar Disorder↗
PubMed1991

Mono(ADP-ribosyl)ation of poly(ADP-ribose)polymerase by cholera toxin.

Poly(ADP-ribose)polymerase (PADPRP) was found to be an efficient protein acceptor for the arginine-specific ADP-ribosylation reaction catalyzed by cholera toxin (CT). The covalent modification of PADPRP was carried out with [32P]2'-dNAD as a selective mono(ADP-ribosyl)ation substrate. Mono(2'-dADP-ribosyl)ated-PADPRP was identified by autoradiographic analysis of the CT reaction products following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Addition of recombinant ADP-ribosylation factor (rARF), a small GTP-binding protein that stimulates the enzymatic activity of CT, enhanced the mono(2'-dADP-ribosyl)ation of PADPRP in a time- and substrate-dependent manner. In contrast, rARF did not change the ADP-ribose polymerizing activity of PADPRP. Peptide mapping mapping of [32P] labeled (2'-dADP-ribose)-PADPRP, following partial proteolysis with papain, revealed that the DNA-binding domain of PADPRP contained the mono(2'-dADP-ribosyl)ated arginine residue(s). Our results are consistent with the conclusion that PADPRP is susceptible to arginine-specific mono(ADP-ribosyl)ation catalyzed by CT.

ADP Ribose Transferases↗
PubMed1991

Diagnosis of cysticercosis in endemic regions. The Cysticercosis Working Group in Peru.

Taenia solium cysticercosis is a frequent cause of neurological disease in developing countries. Specific diagnosis of cysticercosis is difficult. We obtained serum and/or CSF samples from 204 consecutive patients admitted to a neurological ward in Lima, Peru, and looked for antibodies specific for T solium with the enzyme-linked immunoelectrotransfer blot (EITB) assay. 21 (12%) of 173 serum samples from these patients were EITB-positive. In contrast, only 2 (1.5%) of 135 patients attending a public endoscopy clinic and 1 (1%) of 88 patients attending a private endoscopy clinic were seropositive. 1 (1%) of 98 pregnant women living in a Lima shanty town was EITB-positive. 15 (58%) of 26 neurology patients diagnosed clinically as having cysticercosis were seronegative. Routine screening by EITB of all patients with neurological symptoms from areas of endemic cysticercosis would avoid misdiagnosis of this common and treatable disease.

Adolescent↗
PubMed1991

Visual motion perception from stimulation of the human medial parieto-occipital cortex.

Visual phenomena evoked by direct electrical stimulation of extrastriate cortex were observed in 30 epileptic patients as part of a presurgical investigation. An incremental sequence of low-level bipolar stimulation trains was delivered at medial and lateral pairs of contacts of stereotaxically-implanted multilead intracerebral electrodes in parietal, occipital and posterior temporal regions. Diffusion of stimulus afterdischarges was monitored by electrodes in temporal and frontal lobes and by the non-stimulated contacts of the stimulated electrode. Localized stimulations evoked few visual phenomena. The strongest anatomo-perceptual correlation was found for stimulation in the medial parieto-occipital fissure which evoked visual motion phenomena in all three patients stimulated in that region. The evoked motion perceptions were not associated with eye movements or any particular localization of the epileptic focus. These perceptions were only evoked once outside of the medial PO region at the 61 sites examined. The results suggest that the medial parieto-occipital region is closely linked to the human visual motion processing system.

Brain Mapping↗
PubMed1991

Long-term effects of depot-medroxyprogesterone acetate on lipoprotein metabolism.

To assess the effects of depot-medroxyprogesterone acetate (DMPA) upon serum lipids and lipoproteins, a comparative study in chronic users and new acceptors was undertaken. Two groups of women of reproductive age were included in the study; group I (n = 8) was formed by new acceptors whereas, group II (n = 14) constituted DMPA users of more than five continuous years (7.0 + 2.1 years). Blood samples were taken on the day of injection and 15, 29, 57 and 92 days after the i.m. administration of 150 mg of DMPA for the measurement of total triglycerides (TG), cholesterol (CHOL) and phospholipids (PHL). In addition, the TG and CHOL content in the very low density (VLDL), low density (LDL) and high density (HDL) lipoprotein fractions obtained by ultracentrifugation were also determined. The results demonstrated a moderate increase in the serum total TG concentrations at the expense of the VLDL fraction in the group of chronic DMPA users. In both groups, the administration of DMPA induced a moderate, though not significant, decrease in total CHOL and HDL-chol, an effect that was noticed at the end of the treatment interval; the serum LDL-chol content remained unchanged. In addition, a decrease in the total serum phospholipids content was noticed after DMPA injection in both groups, which resembled the fluctuations observed in the luteal phase of normal ovulating women. The overall data indicate that acute and/or chronic DMPA administration at the dose currently employed for contraception does not induce major abnormalities in lipoproteins in serum.

Adult↗
PubMed1991

A retrospective study of disposable extended-wear lenses in 100 patients.

A retrospective evaluation of 100 patients who wore disposable extended-wear contact lenses is presented. The patients were selected at random and were fitted with one of three lens brands approved for extended wear. There were 37 males and 63 females in the study. The mean age was 40.1 years (range, 14 to 76 years). Sixty-seven of the patients wore nondisposable extended-wear soft contact lenses before being fitted with disposable lenses. Complications were noted and included two instances of infectious ulcerative keratitis and six cases of peripheral corneal infiltrates. It is believed that the rate of complications is due to the ongoing hypoxic effect of prolonged use of extended-wear or other contact lenses and may be improved by providing a greater variety of lens fitting parameters. Disposable extended-wear lenses may be a reasonable means of vision correction in the appropriately selected patient and with proper follow-up. At the same time, caution should be exercised in the fitting and wear of disposable extended-wear lenses.

Adolescent↗
PubMed1991

Detection of linkage for heterogeneous disorders by using multipoint linkage analysis.

We have compared the efficiency of the lod score test which assumes heterogeneity (lod2) to the standard lod score test which assumes homogeneity (lod1) when three-point linkage analysis is used in successive map intervals. If it is assumed that a gene located midway between two linked marker loci is responsible for a proportion of disease cases, then the lod1 test loses power relative to the lod2 test, as the proportion of linked families decreases, as the flanking markers are more closely linked, and as more map intervals are tested. Moreover, when multipoint analysis is used, linkage for a disease gene is more likely to be incorrectly excluded from a complete and dense linkage map if true genetic heterogeneity is ignored. We thus conclude that, in general, the lod2 linkage test is more efficient for detecting a true linkage when a complete genetic marker map is screened for a heterogeneous disorder.

Child↗