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Biomedical subjects

P Leflon

Publications and source records attributed to P Leflon.

25 records · Page 2Linked to original sources
PubMed1985

The desferrioxamine test predicts bone aluminium burden induced by A1(OH)3 in uraemic patients but not mild histological osteomalacia.

Desferrioxamine (DFO), a chelating agent of aluminium was administered to 27 uraemic patients on chronic haemodialysis or haemofiltration with a minimal parenteral exposure to aluminium but taking various amounts of A1(OH)3 for about two years. All these patients had a double bone biopsy for measurement of their aluminium content and histomorphometric evaluation. Bone aluminium of our patients were 10 times greater than in our uraemic controls. Plasma aluminium increase (delta A1) induced by DFO correlated better than basal plasma aluminium with bone aluminium and cumulative dose of A1(OH)3 correlated with bone aluminium and delta A1 DFO. None of the patients had florid osteomalacia and only two had traces of aluminium staining. However 16 had mild mineralisation defect as demonstrated by low mineral appositional rate. The aluminium parameters were not different between the two groups of patients with or without mild mineralisation defect. It is concluded that the DFO test predicts bone aluminium but not mild histological osteomalacia in uraemic patients moderately aluminium over-loaded with phosphate binders.

Aged↗
PubMed1985

Influence of biochemical and hormonal factors on the bone histomorphometric features of uraemic patients.

A multidimensional analysis was used to evaluate, the influence on bone histology of various biochemical and hormonal factors in 20 uraemic patients on chronic haemodialysis or haemofiltration. A positive relationship (p less than 0.1) was found between PTH and osteoclastic and osteoblastic surfaces but not with mineral apposition and bone formation rates. The mineral appositional rate which reflects the cellular activity of osteoblasts was positively related to D metabolites 25(OH)D3 and 1,25(OH)2D3 and to phosphate (p less than 0.1). Mineral appositional rate and bone formation rate were negatively related to bone aluminium (p less than 0.05). These data indicate that: 1) PTH simulates bone turnover but has no direct effect on the bone cellular activity of osteoblasts which is mainly dependent on D metabolites and phosphate; 2) mild aluminium overload not severe enough to cause osteomalacia decreases bone formation in uraemic patients. This study evaluates the role of various simultaneously measured biochemical and hormonal factors on bone histological parameters in uraemic patients.

Adult↗
PubMed1985

Magnesium renal wasting in calcium stone formers with idiopathic hypercalciuria contrasting with lower magnesium:calcium urinary ratio.

Plasma magnesium (PMg) and urinary calcium (UCaV) and magnesium (UMgV) were measured after four days of calcium-restricted diet in 60 controls and 82 patients classified according to their calcium excretion in three groups: normo-calciuric (NCa), dietary hypercalciuria (DH) and idiopathic hypercalciuria (IH). When compared to controls, higher UMgV (4.26 +/- 0.28 mmol/d versus 3.4 +/- 0.16, p less than 0.01), lower PMg (0.79 +/- 0.01 mmol/d versus 0.84 +/- 0.01, p less than 0.05) and lower UMg/UCa ratio (0.6 +/- 0.04 versus 1.68 +/- 0.15, p less than 0.001) were observed only in IH. A significant correlation between UMgV and UCaV was found in controls, in NCa and in DH but not in IH. In conclusion, (1) the coexistence of a higher UMgV and of a lower PMg in IH suggests that there is a magnesium depletion in this group of patients; (2) since the lower UMg/UCa ratio may favour a higher propensity for calcium crystallisation and is seen only in IH, magnesium supplements may be specially indicated in this group.

Calcium↗
PubMed1984

[Characterization of L-threonine deaminase activity of guinea pig liver induced by a high protein diet].

In a foregoing paper, we demonstrated that under equilibrated diet conditions, guinea pig liver L-threonine deaminase activity should be allocated to two distinct enzymes: a specific L-threonine deaminase without activity toward L-serine and a L-serine deaminase having a secondary activity toward L-threonine. In the present work, we observed that a high protidic diet caused an elevation of total threonine deaminase activity. Thus purification of guinea pig liver L-threonine deaminase was attempted, using ultracentrifugation, salt precipitation, heat treatment, ion exchange chromatography on DEAE Sephacel, Sephadex G 200 molecular sieve, 2 amino-2 methyl-1 propanol linked CH 4B Sepharose chromatography. The weak variations of the ratios of specific activities respectively toward L-threonine and L-serine observed at each stage of the purification procedure indicated that both activities are very likely supported by a single enzyme preexisting in the liver of guinea pigs fed an equilibrated diet. No isoenzyme was evidenced by polyacrylamide gel electrophoresis or DEAE Sephacel chromatography. Moreover, our purification procedure demonstrated that not only inducible L-threonine deaminase guinea pig liver activity was due to L-serine deaminase, but also that an initially existing specific L-threonine deaminase activity paradoxically disappeared with a protein rich diet.

Animals↗
PubMed1976

[Guinea pig liver cytosol has an L-threonine deaminase activity distinct from L-serine deaminase].

Using sodium sulfate precipitation, "Sephadex G200" gel filtration and polyacrylamide gel electrophoresis, a L-threonine desaminase was demonstrated in the Guinea-Pig liver cytosol. This enzyme was separated from the guinea pig liver L-serine desaminase possessing an auxiliary activity on L-threonine substrate described by us in a previous work. The optimals for pH (7,1) and temperature (+ 55 degrees C) and the apparent molecular weight (134,000 + 20,000) were established.

Animals↗
PubMed1975

[Determination of blood iron and the total fixation capacity of transferrin by a simple automatic technic without dialysis].

An automated method without dialysis for determining serum iron is described. It is an adaptation of the Lauber procedure to the Technicon Auto Analyser I: serum iron is split from its protein combination by exposure to an acetate pH 5.8 buffer, in the presence of a detergent (Teepol 710) which prevents any precipitation of proteins. Iron is maintained in ferrous state by addition of sodium dithionite and is quantitated with bathophenanthrolin colorimetry. Serum samples are analysed at a rate of 60/H. It is necessary to run a blank for each serum sample. Between 20 and 500 mug iron/100 ml the color intensity agrees with Beer's law. The reproducibility is good, and the variation coefficient less than 1.2 per cent. Our results are not significatively different of those obtained with the ICSH standard method. Bilirubin does not interfere. Iron added is satisfactorily recovered. Our method can also be used for determining the transferrin iron binding capacity.

Autoanalysis↗