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Biomedical subjects

M A Arbós

Publications and source records attributed to M A Arbós.

7 recordsLinked to original sources
PubMed1998

Familial multiple symmetric lipomatosis associated with the A8344G mutation of mitochondrial DNA.

We describe familial multiple symmetric lipomatosis in a pedigree harboring the 8344 mutation in the tRNA(Lys) gene of mitochondrial DNA (mtDNA). The proband showed neuromuscular involvement but lacked the typical manifestations of myoclonic epilepsy and ragged-red fibers disease. The distribution of the mutation was unusual because the proportion of mutated genomes was higher in blood and lipomas than in muscle tissue.

Adult↗
PubMed1998

Effect of starvation on organ blood flow in the senescent rat.

To investigate the amino acid requirements of the senescent rat, as part of a study directed toward nutritional support in the aged, it was necessary to determine amino acid levels in plasma and tissue, but also regional blood flow of the animals subjected to fast. Only this latter allows the determination of the amounts of each amino acid present in the tissue before starvation by extrapolation of values measured during starvation. As plasma and tissue amino acid had been previously determined, the aim of this study had been to measure regional blood flow in the liver, kidney, testis, spleen, stomach, small intestine and large intestine in senescent rats submitted to 1, 5, 9 and 15 days of starvation. Twenty-four-month-old male Wistar rats (n = 16) were divided into four groups (n = 4), and submitted to starvation for 1, 5, 9 and 15 days. Blood flow in the liver, kidney, testis, spleen, stomach, and small and large intestine was measured by injecting 0.5 ml of a microsphere solution (15 microns diameter) labelled with 57Co, 0.25 microCi/ml. Over the 15-day period studied, the response to starvation showed two distinct phases: an early effect (from day 1 to day 9) in which there were decreases in the weight of the organs and in organ blood flow, and a second phase (from day 9 to day 15) in which blood flow and organ weight were maintained. However, organ blood flow related to mass was not substantially affected by starvation. This implies that measurement of substrate plasma concentration alone can reliably reflect organ substrate flow.

Aging↗
PubMed1994

Effect of medium chain triglycerides (MCT) on jejunal mucosa mass and protein synthesis.

The effects of medium chain triglycerides (MCT) on jejunal mucosa mass and protein synthesis were compared with results from previous experiments with rats fed by parenteral nutrition or enteral nutrition. Other published studies have also been analysed. Three experimental models were studied. In the traumatic model, production of a femoral fracture was followed by Kirschner pin insertion into the medullary canal of both fragments at reduction. (Forty ras were fed enteral nutrition and 93 were given parenteral nutrition.) A second model entailed resection under ether anaesthesia using the technique described by Higgins. (Fifty five rats were fed enteral nutrition and 28 with parenteral nutrition.) A third model entailed a terminolateral portocaval shunt under anaesthesia with pentobarbital. (Sixty nine rats were treated this way and then given enteral nutrition.) Proportions of medium chain/long chain triglycerides (LCT) were as follows: 0/100, 20/80, 40/60, 50/50, and 92/8 for enteral nutrition and 0/100, 30/70, 50/50, and 70/30 for parenteral nutrition. Faecal losses of alpha amino nitrogen, protein, total fats, and free fatty acids were analysed together with the quantitative intake, weight gain of the rats, jejunal mucosal mass, and protein synthesis in relation to the MCT proportion ingested or given by enteral nutrition or parenteral nutrition. From analysis of our results and those of others, several conclusions could be drawn. Firstly, the route of administration of MCT is extremely important and enterocytes might be considered one of the main target sites. Secondly, a high proportion of MCT (more than 80%) offers no advantage for jejunal mucosa and produces undesirable side effects. Thirdly, the effect of MCT on jejunal mucosal protein synthesis depends on the metabolic state. Finally, an increase in jejunal mucosal mass directly correlated with MCT concentrations, but no correlation was found between mass and protein synthesis. A positive correlation, however, between MCT proportion and enzyme activity (alkaline phosphatase and sucrase) in the brush border membrane was seen as well as a positive correlation with the concentration of phospholipids in the microvilli.

Animals↗
PubMed1993

Ketoisocaproate contamination errors in protein synthesis determinations using L[1-14C]leucine.

Protein synthesis rate determinations in vivo using L-[1-14C]-leucine may be underestimated because of contamination by radioactive ketoisocaproate (KIC) resulting from leucine metabolism. The aim of this work was to set up a reliable method to determine the KIC/leucine radioactivity ratio in protein-free homogenates, and to apply it to study the extent of the protein synthesis ratio error due to KIC contamination. Cation-exchange chromatography using Dowex AG 50W-X8 resin was used to separate KIC from leucine, eluting KIC with water and leucine with 4 M ammonia. The errors found in the protein synthesis ratio were 6.20% in liver and 2.34% in jejunum.

Animals↗
PubMed1990

Quality goals for hormone testing.

Estimates of intra-individual biological variation in normal subjects have been made for 17 hormones commonly measured for diagnostic purposes and the results have been compared with state-of-the-art analytical imprecision data. The implications of using these results for setting goals for analytical performance are discussed.

Adult↗
PubMedDate not supplied

Thiolprotease activity in skeletal and myocardial muscle and liver of fasted rats.

The activity of the thiolproteases, cathepsins B, H, and B + L, one of the most important groups of endoproteases, was measured in skeletal and myocardial muscle and liver of Sprague-Dawley rats submitted to fasts of different duration (control and 24, 48, and 72 h). After the fasting period, the animals were killed, and fresh tissue samples were collected. Enzyme activity was determined in vitro with the specific substrates Z-Arg-Arg-MCA for cathepsin B, Z-Phe-Arg-MCA for cathepsin B + L, and Arg-MCA for cathepsin H. Results show different patterns in the organs studied: activity increased linearly in liver, decreased in myocardial muscle, and had no change in skeletal muscle. These results suggest that the expected alteration observed in proteolytic activity in fasted tissues is produced to a certain degree by changes in thiolprotease activity.

Animals↗