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Biomedical subjects

M C Marín

Publications and source records attributed to M C Marín.

13 recordsLinked to original sources
PubMed2006

p73 cooperates with Ras in the activation of MAP kinase signaling cascade.

The p73 gene is capable of inducing cell cycle arrest, apoptosis, senescence, differentiation and to cooperate with oncogenic Ras in cellular transformation. Ras can be considered as a branch point in signal transduction, where diverse extracellular stimuli converge. The intensity of the mitogen-activated protein kinase (MAPK) cascade activation influences the cellular response to Ras. Despite the fundamental role of p53 in Ras-induced growth arrest and senescence, it remains unclear how the Ras/MEK/ERK pathway induces growth arrest in the absence of p53. We report here that oncogenic Ras stabilizes p73 resulting in p73 accumulation and enhancement of its activity. p73, in turn, induces a sustained activation of the MAP kinase cascade synergizing with oncogenic Ras. We also found that inhibition of p73 function modifies the cellular outcome to Ras activation inhibiting Ras-dependent differentiation. Here, we show for the first time that there is a signaling loop between Ras-dependent MAPK cascade activation and p73 function.

Animals↗
PubMed2005

Long-chain polyunsaturated fatty acids in breast milk in La Plata, Argentina: relationship with maternal nutritional status.

Milk fat is the major source of energy for breastfed infants; it also supplies polyunsaturated fatty acids (PUFAs) essential for the development of brain, retina, and other organs. Maternal nutritional status is critical for the newborn, and little information exists regarding the PUFA status of vulnerable populations living in Southern regions. We studied the relationship between maternal nourishment and milk fatty acid composition. Mother nutritional status (normal, overweight or obese) was estimated on the body mass index. Milk protein, total lipid, and fatty acid composition were determined. Milk protein was not affected by mother's nutritional status. In obese mothers an increase in lipid content, linoleic acid, total n-6 and total PUFAs was observed comparing to the other groups. Disregarding the nutritional status, the ratio n-6/n-3 fatty acids was very high and the 22:6n-3 content was very low, when compared with those of mothers from other countries. This finding led us to urge Public Health officers to promote changes in the dietary habits of nursing women.

Adolescent↗
PubMed2004

[A 41 year-old female with abdominal pain and fever of 24 hours].

A 41 year-old female with intrauterine contraceptive device (ICD) from 8 year ago that complained fever and abdominal pain during 24 hours and leucocytosis. The radiology examination tests showed cegal, appendiceal, and right ovary enlargement with swollen of fat adjacent. In the differential diagnosis should be include: appendicitis, diverticulitis, chronic inflammatory digestive disease or mesenterical adenitis. In the differential diagnosis included: ovarian neoplasm, endometriosis, ectopic pregnancy, ovarian torsion and pelvic inflammatory diseases. From pelvic infections, it is import consider pelvic inflammatory disease, genital tuberculosis and pelvic actinomycosis. With the antecedent of ICD, the clinic and the radiological finding as abdominal mass with invasion of adjacent structures and absence of adenopathy; the first diagnosis is a abdominopelvic actinomycosis and the second is a genital tuberculosis.

Abdominal Pain↗
PubMed2000

A genetic approach to detect muscle protein interactions in vivo.

An organism is required to identify biologically relevant protein interactions. We propose Drosophila and its indirect flight muscles as a suitable experimental system for genetic screenings for muscle protein interactions. The first attempt focused on troponin I (TnI) in view of the key role in thin filament regulation that this protein performs. Suppressors of a defined Tn I allele have been isolated as mutations in the heavy chain of myosin (MhC). This unsuspected functional interaction between TnI and MhC serves to illustrate one of the benefits of the approach. Four of the suppressors identified to date reside in the MhC head, around the actin-binding site and near the lips of the pocket where ATP is hydrolyzed. Two other suppressors correspond to a second site mutation in TnI and a mutation in the conserved region of Tropomyosin II (TmII), respectively. All the identified suppressors are mutations in constituents of the sarcomere, and most of them are structurally similar to human mutations causing familial hypertrophic cardiomyopathy (FHC). At least seven sarcomere proteins can lead to FHC and, consequently, the disease is heterogeneous and difficult to diagnose. In addition, putative natural suppressors may help obscure the origin of FHC. The genetic procedure, used here for muscle proteins, could help diagnose FHC and other myopathies, and extend to proteins of clinical interest in other tissues, including the nervous and circulatory systems.

Animals↗
PubMed2000

Dietary long-chain fatty acids and visual response in malnourished nursing infants.

Polyunsaturated fatty acids (PUFAs) derived from essential fatty acids (EFAs) play an important role in prenatal visual and neural development. Protein-energy malnutrition affects PUFA supply, and hence the synthesis of structural lipids during growth. Recently, some physiological studies reported abnormalities in the visual function of formula-fed infants relative to breast-fed infants. The purpose of our study was to assess whether fatty acid composition of the malnourished infant diet modifies the visual function and erythrocyte phospholipid fatty acid composition. Three groups of full-term malnourished infants were selected. Two groups received commercial formulas. One of them supplied linoleic and alpha -linolenic acid: Formula I (FI), and the other supplied, in addition, long-chain PUFAs from n-3 and n-6 series: Formula II (FII). A reference group of breast-fed infants was also enrolled. Visual function was assessed using full-field flash electroretinography, and the erythrocyte phospholipid fatty acid composition was determined by gas-liquid chromatography. Those infants receiving the supplemented formula (FII) exhibited a similar retinal function to that of breast-fed infants. However, normal results were not achieved when infants were fed on the FI formula. In all groups, the results were correlated with the proportion of docosahexaenoic acid in erythrocyte phospholipid fatty acid composition. We conclude that in malnourished infants a nutrient formula enriched with long-chain fatty acids of n-6 and n-3 series could be helpful to achieve an erythrocyte fatty acid pattern and a visual function similar to that obtained in breast-fed infants.

Breast Feeding↗
PubMed1997

Changes in gastrin and serum pepsinogens in monitoring of Helicobacter pylori response to therapy.

The aims of this study in 50 patients with H. pylori infection and duodenal ulcer were to examine the effect of eradication therapy on the serum levels of gastrin, pepsinogen I, and pepsinogen II and to investigate whether monitoring of the serum changes in these peptides after treatment could predict patient outcome. H. pylori status was assessed at entry and one and six months after therapy by culturing and microscopic analysis of the gastric mucosa and by [14C]urea breath test. Significant decreases were observed in the serum levels of gastrin (-11.4 +/- 3%), pepsinogen I (-28.9 +/- 4%), and pepsinogen II (-40.4 +/- 3%) in the 45 patients whose infection was eradicated, but not in the patients without eradication. Serum values of these peptides were unchanged in an additional group of 10 patients that only received omeprazol, none of whom had H. pylori eradicated. The best cutoff point of the percentage of each peptide to predict patient outcome was 10% for gastrin and pepsinogen I, and 15% for pepsinogen II. A pepsinogen II decrease > 15% resulted in the best marker of H. pylori clearance, accurately identifying patient outcome 86.6% of the time, whereas the diagnostic accuracy of gastrin and pepsinogen I was 61.7% and 76.6%, respectively. Significant correlations were found between the bacterial load assessed by histology with the serum concentrations of pepsinogen I and II and with the urease activity as measured by the amount of 14CO2 excreted. In conclusion, eradication of H. pylori infection is followed by a significant drop in serum levels of gastrin, pepsinogen I, and pepsinogen II. Changes in the latter are the most uniform and may be used as an indirect tool to predict treatment outcome.

Adult↗
PubMed1995

Protein-energy malnutrition during gestation and lactation in rats affects growth rate, brain development and essential fatty acid metabolism.

The influence of feeding a low protein diet to rat dams during gestation and lactation on lipid metabolism in pups was studied. Wistar rats were fed 5, 10, 15 and 25% dietary protein during gestation and lactation. Pup growth was monitored until weaning, and brain weight, protein concentration, proteolipid concentration and total lipid phosphorus concentration of brain were analyzed. The levels of fatty acids in dam milk as well as in pup liver phospholipids and brain prosphatidylcholine and phosphatidylethanolamine were determined. The progressive deprivation of maternal dietary protein produced a reduction in the total saturated fatty acid concentration of dam milk and an increment in the concentration of nonmetabolized linoleic acid. Pup body and brain weights as well as proteolipid, protein and total lipid phosphorus concentrations in brain were reduced in proportion to the degree of dietary protein deficiency. The products:precursor ratio of (n-6) fatty acids in liver phospholipids revealed an impairment in the elongation-desaturation pathway due to maternal protein deficiency. Both (n-6) and (n-3) polyunsaturated fatty acids within brain phosphatidylethanolamine were decreased by reduced maternal dietary protein intake, whereas only the linoleic acid-derived products were similarly affected in the corresponding phosphatidylcholine fraction. These results demonstrate the widespread and profound deleterious effects of low protein levels of maternal diet on the growth rate, brain development and fatty acid metabolism in rat pups.

Analysis of Variance↗
PubMed1994

[Effect of the administration of corn oil on the composition of fatty acids of plasma phospholipids in normal and malnourished infants fed with cow's milk].

The effect of corn oil diet administration on the essential fatty acids (EFAs) profiles was evaluated in plasma phospholipids from normal and malnourished cow's milk fed infants nursing infants. A control group of only breast-fed was also selected for this study. The fatty acid composition was determined by gas-liquid chromatography and used as biochemical variable for evaluating EFA status. A fall in the proportion of fatty acids concomitant with an increase in the saturated fatty acids, consistent with a pattern of essential fatty acid deficiency (EFAD) was observed in the cow's milk fed infants, either normal or malnourished (Table 2). The corn oil administration was capable of restoring the fatty acid profile to normal values, similar to the values of the control group of breast-fed infants, even in malnourished infants, although during the 15 days test they did not correct their clinical syndrome of malnutrition (Table 3). Calculation of the product-precursor of the linoleic acid provided evidence for the positive effect of the corn oil administration.

Animals↗
PubMed1991

Interrelationship between protein-energy malnutrition and essential fatty acid deficiency in nursing infants.

The influence of severe protein-calorie malnutrition on essential fatty acid (EFA) status was evaluated in nursing infants aged 2-5 mo. A control group of the same age and with normal weight-for-height was also selected for this study. The fatty acid pattern of total phospholipids from plasma and red blood cells (RBCs) was determined and then used as a biochemical variable for evaluating EFA status. A sharp fall in the relative percentage of n-6 (omega-6) fatty acids concomitant with an increase in the n-9 fatty acids in plasma and RBC phospholipids was observed. These results are consistent with the picture of EFA deficiency and showed that the deficiency state is well correlated with the severity of malnutrition. Calculation of the product-precursor ratio of polyunsaturated fatty acids derived from linoleic acid (18:2n-6) in RBC phospholipids provides evidence for an impairment in the elongation-desaturation pathway promoted by the protein-calorie malnutrition.

Breast Feeding↗
PubMed1990

Different HCl and pepsinogen I secretion patterns in anatomically defined gastric ulcer subsets.

Anatomically, functionally, and clinically, peptic ulcer patients are a heterogeneous group of subjects. These patients can be classified according to the anatomic localization of the niche. The functional state of the gastric mucosa was studied in 30 gastric ulcer patients, 25 duodenal ulcer patients, and 10 normal controls. The classification of the first group was based on Johnson's criteria, with the following results: 10 individuals were type I, 10 were type II, and 10 were type III. Pepsinogen I levels and gastric acid secretion were measured in all 65 subjects under basal conditions and after subcutaneous pentagastrin stimulation. Both basal and stimulated serum pepsinogen I values were significantly higher (p less than 0.05) in gastric ulcer type III patients than in the other four groups. These values in gastric ulcer type I were similar to those of the controls. Gastric ulcer type II patients showed an intermediate functional state similar to that of duodenal ulcer patients. In both gastric ulcer type II and duodenal ulcer patients, the basal and stimulated pepsinogen I levels were significantly higher (p less than 0.05) than those found in controls, whereas the basal serum gastrin levels were similar in the five groups. In conclusion, different HCl and pepsinogen I secretory patterns, with functional heterogenicity of the gastric mucosa, are shown here for the anatomically defined gastric ulcer subsets.

Adult↗
PubMedDate not supplied

Virus characterization and sequence of the fusion protein gene cleavage site of recent Newcastle disease virus field isolates from the southeastern United States and Puerto Rico.

Nine Newcastle disease virus (NDV) isolates obtained from Puerto Rico, Georgia, Alabama, Mississippi, and Texas were analyzed for in vivo pathogenicity, biological properties (hemagglutination of mammalian erythrocytes), and for sequence variation at the amino acid and sense RNA level of the fusion protein cleavage site. Intracerebral pathogenicity index values ranged from 0 to 0.3 and the intravenous pathogenicity index obtained for all isolates was 0. Four isolates hemagglutinated bovine erythrocytes, whereas no hemagglutination was observed using equine erythrocytes. By direct sequencing of reverse transcription polymerase chain reaction products, all the isolates had a predicted fusion cleavage sequence comparable to lentogenic NDV strains. Based on nucleotide sequence, the viruses could be grouped phylogenetically with the B1 vaccine-type virus. However, nucleotide sequences were not 100% similar to the B1 or La Sota NDV strains, indicating that minor genetic heterogeneity occurs among lentogenic field isolates of NDV.

Amino Acid Sequence↗