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Biomedical subjects

J M Culebras Fernández

Publications and source records attributed to J M Culebras Fernández.

18 recordsLinked to original sources
PubMedDate not supplied

[Nutrition and colorectal cancer].

Colorectal cancer is the most common tumor behind lung cancer in men and breast cancer in women. Its prevalence shows a wide geographic variability, which, along with epidemiological and experimental evidence, suggests a considerable participation of environmental factors, mainly dietary in its cause. It is not known which dietary components have an undisputed influence on the risk of colorectal cancer, nor how they condition the different genetic susceptibilities of the individuals. However, we do know of the protective action that consuming vegetables has, and the increased risk associated with saturated fats and red meats, especially when associated with other factors like a hypocaloric diet, obesity, sedentary life, or the use of alcohol. Fiber, however, has not proven the risk reducing properties that were attributed to it by epidemiological studies, possibly because this term encompassed several very different substances. Moreover, it is very difficult to know the effect of an isolated nutrient as these are intimately entwined in the foods. It should be kept in mind that many substances, like plants, as well as the usual nutrients, contain a large number of components with unknown effects and that the manner in which the foods are prepared or eaten, no doubt are of influence. A healthy lifestyle with regard to the risk of colorectal cancer, should no doubt include the consumption of large amounts of vegetables and whole cereals, a limit of the caloric intake with fats not exceeding 30%, to eat fish and chicken rather than red meat, to avoid alcohol, and to regularly partake of physical exercise.

Central Nervous System Depressants↗
PubMedDate not supplied

[Women and children first?....].

The goal of the National Health System (SNS in its Spanish acronym) does not consist in distributing to everyone an identical dose of health services but in establishing a balance between those who are ill and those who are healthy in the course of their lives, and concentrating its interventions on those who are worse. In an advanced health care system, there are very few actions by health personnel that can be assessed as "lives saved": more often than not, these actions manage to delay the end and are occasionally limited to improving the quality of the years patients live, without extending their number. It is therefore clearly necessary to find appropriate units of measurement to assess the benefits and utility of all health-related procedures. When effecting a cost-effectiveness study and assessing the results obtained, it is necessary to differentiate between quality of life (personal), utility (personal) and the utility of the procedure or process when applied to our patients. This utility is determined by means of the additional quality and quantity of life, measured in a single unit, QALY, but this cost-effectiveness analysis would be constrained in patients with a shortened life expectancy and/or reduced quality of life due to old age or degenerative disease, thus skewing the distribution of resources in favour of younger population groups. In order to redress this situation, the use of corrective measurements such as EQALY is proposed. We believe that neither age nor illness in themselves limit the application of resources, providing that we can prove a useful result for the patient.

Adult↗
PubMedDate not supplied

[Hepatic metabolism of cholesterol].

Cholesterol is an essential component of all tissues, as it is a part of the structure of cell membranes, and it is an immediate precursor of a series of essential substances such as vitamins, steroid hormones, and bile acids. Under physiologic conditions, the intake and output of cholesterol in the organism is coordinated and balanced with the aim of guaranteeing the availability of adequate amounts of cholesterol to satisfy the needs of the different tissues (fig. 1). Under pathological conditions there is an imbalance between these mechanism, which leads to an increase in the circulating levels of cholesterol, leading to pathological processes such as hyperlipemias, atherosclerosis and bile stones. The liver plays a central role in the regulation of the homeostasis of cholesterol. The molecule enters the liver in the form of chylomicrons and low density lipoproteins (LDL), through lipoprotein receptors, and this is also the most important organ for the de novo biosynthesis of cholesterol from acetyl coenzyme A, by means of a cascade enzyme reaction in which the enzyme 3-hydroxy-3 methyl glutaryl CoA reductase (HMG-CoA) is the key of the entire process. Cholesterol is found in the liver in the form of cholesterol esters or as free cholesterol. The two most effective ways of eliminating body cholesterol are found in the liver, with the degradation of the compound to bile acids and the biliary secretion of cholesterol. The conversion to bile acids takes place through a series of enzymatic steps in which the formation of 7-alpha-hydroxycholesterol by the enzyme cholesterol 7-alpha-hydroxylase is the key of the process. The biliary secretion of cholesterol is 600 mg/day. Both the abundance and the universality of cholesterol in living things as its clinical implications emphasize the importance and interest of this compound.

Bile↗
PubMedDate not supplied

[Amino acid pattern variation in animals after the administration of hypocaloric peripheral parenteral nutrition].

The pattern of intracellular aminoacids may be reproduced individually and is different for each illness. This study seeks to measure alterations in this pattern in rats after the administration of hypocaloric peripheral parenteral nutrition (HPPN), group B, for five days, by comparing them with rats subjected to conventional fluidtherapy, group A, for the same period. HPPN tolerance was good in all cases. Our results show a higher tendency to glyconeogenesis in group A, measured by a reduction in the glycogenic aminoacids especially alanine. An increase in branched aminoacids was observed in group A due to an increase in proteolisis. The animals in group B showed a lesser reduction in the intracellular aminoacids necessary for glyconeogenesis, especially glycine. HPPN, was found, to alter the aminoacids pattern in fasting rats. The results might be corroborated in humans studies.

Amino Acids↗
PubMedDate not supplied

[Magnesium: metabolism and requirements].

Magnesium is an important element in health and in disease, it is the organism's second most abundant intracellular cation, after potassium, and it is the main divalent intracellular cation. Its metabolic importance is well known, as it has been identified as a cofactor in more than 300 enzymatic reactions which affect the energetic metabolism, and the synthesis of proteins and nucleic acids, Hypomagnesemia is a frequent finding in hospitalized patients, even more so when the patients are critical (+/-65%). Although low serum levels of magnesium imply the presence of intracellular depletion, normal serum magnesium levels may be present in situations of intracellular magnesium depletion, with important clinical repercussions. Keeping in mind that only 1% of the body's magnesium is in the extracellular fluid, the serum magnesium levels may not adequately reflect the situation, which is why techniques have been proposed which determine the intracellular concentración. The identification of the patients who may potentially present a magnesium depletion, requires a clear knowledge of the risk factors associated with magnesium deficiency: poorly controlled diabetes mellitus, excessive alcohol intake, severe diarrhea, important steatorrhea, and the use of drugs which favor their renal excretion. The present review gives an up date of the most frequent causes of magnesium deficits, giving a series of practical recommendations to prevent this situation, and to undertake a correct replacement therapy. Finally, and although hypermagnesemia appears in a reduced number of circumstances, the presence of kidney failure of diverse etiology, as well as the broadening of the indications of magnesium salts, have increased its incidence, which is why special emphasis is made in this section.

Erythrocytes↗