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Biomedical subjects

M R Ras

Publications and source records attributed to M R Ras.

At least 19 recordsLinked to original sources
PubMed1999

Iron metabolism in burned children.

UNLABELLED: The administration of iron supplementation in children with burns has been a subject of controversy. Recent studies argue against its use in the acute phase of stress. To assess whether iron metabolism parameters show significant differences in the acute phase and the recovery phase of burn, 21 patients (age range: 17 months to 13 years) with burns of more than 10% of body surface who had not received blood transfusions or iron supplementation were studied. Sideraemia, ferritin, transferrin, transferrin saturation index (TSI) and C-reactive protein (CRP) were assessed both in the acute and the recovery phase after burn. Sideraemia, transferrin, and TSI were significantly lower in the acute than in the recovery phase (17.3 +/- 3 vs 53.8 +/- 6.6 microg/dL, 190.5 +/- 15 vs 287.9 +/- 14.3 mg/dL and 7.7 +/- 1.3 vs 15.4 +/- 1.6%, P < 0.0001, P < 0.001 and P = 0.0006, respectively) while plasma ferritin and CRP were significantly higher (84.7 +/- 8.8 vs 43.1 +/- 8.5 ng/mL and 9.5 +/- 1.5 vs 0.7 +/- 0.2 mg/dL, P = 0.016 and P < 0.0001, respectively). When the above parameters were analysed based on age (< or = 2 years, > 2 years), the observed differences persisted. CONCLUSION: Hyposideraemia is a frequent finding in the acute phase of paediatric burns and is accompanied by increased ferritin levels and decreased transferrin concentrations. The low iron values tend to recover without the use of iron supplementation suggesting an endogenous block of iron release in the acute phase and indicates that iron therapy should be not recommended in the initial period of stress of the burned patient.

Acute Disease↗
PubMed1987

High-density lipoprotein cholesterol subfractions in chronic uremia.

Cholesterol content in high-density lipoprotein (HDL) subfractions has been studied in 108 patients at different evolutive stages of chronic renal failure (CRF) under conservative treatment. Results have been compared with healthy control subjects, patients receiving hemodialysis, and renal graft recipients. Significant low levels of total HDL and HDL2 cholesterol are observed in men with CRF. The more severe the CRF, the more likely that total HDL and HDL2 cholesterol will be low. Moreover, a significant inverse correlation is found between HDL2 cholesterol and serum creatinine levels. In women, although a decrease in total and HDL2 subfraction is observed, no significant differences are found across the severity of CRF. Serum HDL2 cholesterol levels are decreased in men and women receiving hemodialysis, while raised total HDL and HDL2 cholesterol levels are observed in normally functioning renal grafts. These results indicate that according to the "HDL hypothesis," despite other associated risk factors, the high cardiovascular mortality rates noted mainly in men with CRF under conservative treatment and in patients receiving hemodialysis could be explained, at least in part, by the sustained and progressive decrease in total HDL and HDL2 values. From this point of view, our study suggests the need to promote early kidney transplantation.

Adult↗
PubMed1987

High-density lipoproteins in untreated idiopathic nephrotic syndrome without renal failure.

Serum apoprotein A-I and lipid composition of high-density lipoproteins in 14 adults and 9 children with idiopathic untreated nephrotic syndrome without renal failure were studied. Serum apoprotein A-I in adults was significantly raised compared to a control group (1.72 +/- 0.49 and 1.45 +/- 0.15 g/l, Mean +/- SD, respectively); a similar trend was observed in children (1.88 +/- 0.62 and 1.52 +/- 0.21 g/l, respectively). High-density lipoprotein cholesterol was normal in both groups of patients (1.19 +/- 0.30 and 1.50 +/- 0.48 mmol/l in adults and in children, respectively), whereas high-density lipoprotein phospholipids were decreased in adults and increased in children. In addition, apoprotein A-I: high-density lipoprotein cholesterol ratios in both groups of patients were significantly increased with respect to their control groups. These alterations suggest the existence of qualitative changes in high-density lipoprotein composition. Despite other associated risk factors, and particularly from the point of view of the 'high-density lipoprotein hypothesis', our patients with untreated nephrotic syndrome without renal failure seem not to be at a higher coronary risk.

Adult↗
PubMed1981

[High density lipoprotein cholesterol. Normal values, influence of vascular risk factors and of a vegetarian diet (author's transl)].

The serum levels of cholesterol bound to high density lipoproteins (HDL-C) were determined by the heparin-manganese chloride precipitation method in 306 subjects, 182 male with ages ranging from 11 to 81 years, and 124 female with ages ranging from 7 to 78 years. Twenty six subjects belonged to a lacto-vegetarian community, while the remaining 280 were healthy volunteers, factory workmen sampled during a regular check-up, and either outpatients or inpatients being evaluated for minor illnesses or minor surgery. None of the subjects had arteriosclerosis or a metabolic disease and, with the exception of the lacto-vegetarians, they were all consuming a normal diet. HDL-C concentrations varied very little among the different age groups. Females had HDL-C values slightly superior to those of males. No significant differences were found between smokers and non-smokers, alcohol drinkers and non-drinkers, and regularly exercising and sedentary people. HDL-C concentrations were independent of total cholesterol and triglyceride levels. Females under oral contraceptive treatment had lower HDL-C levels than control females, but the differences were not statistically significant. Compared with age and sex-matched controls, the lactovegetarians showed similar HDL-C concentrations.

Adolescent↗
PubMed1979

[Bile acids II. Physiopathologic and clinical aspects (author's transl)].

It is generally accepted that the bile acids are responsible for pathologies as a result of deficiency or by toxic action. Quantitative deficiency is difficult to evaluate but the normal pool of bile acids is generally considered to be between 2 and4 grams. Daily loss and replacement by synthesis is thought to be between 500 and 700 mg. There is experimental evidence to demonstrate the toxic action of certain bile acids on metabolic structures and processes. There is no doubt that alterations in the metabolism of bile acids give rise to certain pathologic aspects in some diseases of the gastrointestinal tract or the hepatobiliary system. There are other conditions, on the other hand, in which the study of these acids may reveal significant physiopathologic implications. The first group includes terminal ileopathy, blind loop syndrome, gastric ulcer, gastritis, cholestasis, cirrhosis of the liver, and cholelithiasis. In the second group are such diverse conditions as acute pancreatitis, cancer of the colon, endocrine disturbances, some hyperlipidemias, and others. Much of the present day understanding of the physiopathology of the bile acids will probably have to be revised in the nex few years, in view of the rapid advances being made in this field.

Bile Acids and Salts↗
PubMed1979

[Bile acids. I. Nature, physiology, and functions (author's transl)].

Bile acids play a fundamental role in the degradation and absorption of intestinal lipids. The primary ones are cholic acid and chenodeoxycholic acid which are synthesized from cholesterol in the liver and conjugate with taurine and glycine amino acids. The secondary bile acids are derived from the primary ones by the enzyme action of intestinal bacteria through a process of deconjugation and dehydroxylation. Their detergent property is based on the molecular configuration of these compounds, which present a hydrophilic and a hydrotion of these compounds, which present a hydrophilic and a hydrophobic surface. The different enzymes in the liver cells that intervene in the process of synthesis of bile acids are now known. A basic element in their physiology is the enterohepatic circulation, enabling the organism to take maximum advantage of these compounds. The dynamics of the cycle are maintained and regulated by the system of uptake and secretion of the cells, cholecystokinin, intestinal peristalsis, active transport across the ileal membrane, and by portal venous flow. Much of our knowledge about the biogenesis and functions of the bile acids has been acquired quite recently. Research over the past three decades has contributed to a great advance in our understanding of their physiology.

Bile Acids and Salts↗
PubMed1979

In vivo and in vitro relationship between lipoprotein-X and bile salts in cholestasis.

Bile salts have been shown to act on lipoprotein-X (LP-X) in vitro to induce a false-negative electrophoretic test. The aim of the present study was to investigate the relationship between serum LP-X and serum bile acids in patients with cholestasis. The in vitro concentration of bile salts required to induce a negative or reduced concentration of LP-X was also studied. There was no relationship, either positive or negative, between serum LP-X and bile acids in 34 patients with cholestasis. Serum was incubated with various saline solutions of taurocholic, lithocholic, deoxycholic and glycocholic acids. The concentration of LP-X decreased only after the final concentrations of bile salts were over 2,000 mumole/1. This is more than five times the concentration of serum bile salts usually found in patients with cholestasis. It is concluded that the negative LP-X test in some patients with cholestases must be explained by some other mechanisms than bile salts.

Bile Acids and Salts↗
PubMed1977

The clearance of lipoprotein X in vitro, and effect of phospholipase A on serum lipoprotein X.

The in vitro effect of post-heparin and post-heparin plus post-protamine normal serum on serum lipoprotein X (LP-X) is described. Serum LP-X is cleared after incubation with post-heparin normal serum, and serum LP-X remain unmodified when it is incubated with post-heparin plus post-protamine normal serum. The action of phospholipase A from snake venom on serum LP-X is also studied. A very small quantity of phospholipase is necessary to degrade LP-X and to transform lecithin into lysolecithin. It is concluded that phospholipase seems to be the enzyme that most likely induces the LP-X changes after heparin administration.

Adult↗