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Biomedical subjects

M Olmer

Publications and source records attributed to M Olmer.

At least 19 recordsLinked to original sources
PubMed1992

Chronic and intradialytic effects of high-flux hemodialysis on tumor necrosis factor-alpha production: relationship to endotoxins.

Tumor necrosis factor-alpha (TNF alpha) likely plays a role in hemodialysis-associated complications. As TNF alpha is mainly produced by monocytes in response to endotoxins, we studied its production and the presence of circulating endotoxins in patients dialyzed on polyacrylonitrile (PAN) membrane. Spontaneous production of TNF alpha was observed in patients before the dialysis session and increased during the session. Endotoxins were present in serum from patients chronically dialyzed with PAN and increased during hemodialysis session. In addition, intradialytic decrease in CD14 antigen expression on circulating monocytes, which could be caused by endotoxins, was found. The continuous presence of low amounts of circulating endotoxins between sessions may explain the chronic increase in TNF alpha secretion, while high amounts of circulating endotoxins may account for intradialytic oversecretion of TNF alpha and downmodulation of CD14. We suggest that endotoxin-free dialysates should be a prerequisite for the use of high-flux membranes.

Acrylic Resins↗
PubMed1992

Leishmaniasis: a rare cause of unexplained fever in a renal graft recipient.

We report a case of visceral leishmaniasis in a 38-year-old renal transplant recipient living in an endemic country. Antimonial derivatives induced a rapid remission. A review of the literature disclosed 8 cases of this association with a fatal fulminant outcome in 5 cases. We suggest that the specific immunosuppression used in renal transplant patients might facilitate the development of a dormant infection and in these patients the misleading presentation may delay the diagnosis. Moreover special caution with treatment of leishmaniasis must be taken in renal transplant because of possible interactions between antimony compounds and ciclosporin metabolites. In renal transplant patients living in endemic countries, visceral leishmaniasis should be kept in mind as a potential cause of unexplained long-standing fever and considered as an opportunistic infection.

Adult↗
PubMed1992

[Disturbances of lipid metabolism during nephrotic syndrome: physiopathology and treatment].

Both increased synthesis and decreased catabolism of lipoproteins may account for the severe hyperlipidemia which frequently occurs in patients with the nephrotic syndrome (NS). Nevertheless the complex relation between hyperlipidemia and proteinuria remains unclear and still debated. Increased levels of serum total cholesterol, of low-density lipoprotein and of apolipoprotein B are the most characteristic reported abnormalities placing these patients at high risks for atherosclerotic vascular disease. Moreover recent experiments have suggested that hyperlipidemia may also play a role in the progression of renal disease. Thus the reasons for using hypolipemic treatment are now growing in number and recent trials with lipid lowering medication have been successful without major side effects.

Cardiovascular Diseases↗
PubMed1991

[Physico-chemical mechanisms of the formation of calculi].

Urinary stones are formed in three steps: nucleation, growth and crystal aggregation. These steps are dependent on physicochemical factors such as oversaturation of the urine and presence of substances that promote or inhibit lithogenesis. These mechanisms result in the formation of crystalline particles large enough to be detained in the lumen of renal tubules.

Chemical Phenomena↗
PubMed1991

Haemodialysis membranes modulate chronically the production of TNF alpha, IL1 beta and IL6.

As cytokines may play a role in the adverse effects of haemodialysis, TNF alpha, IL1 beta and IL6 were investigated before the haemodialysis session (chronic effect) and after 30 and 60 min (session effect). We found that haemodialysis exerts a chronic effect on cytokines but the type of haemodialysis membrane, Cuprophan or Hemophan, specifically influences each cytokine. Circulating levels of TNF and unstimulated production of TNF and IL1 by monocytes were increased in patients dialysed with Hemophan, whereas a greater LPS-stimulated production of TNF was observed in patients dialysed with Cuprophan. Both types of membrane induced a higher production of IL6 as compared to controls. The alternate use of Cuprophan and Hemophan demonstrated that the production of TNF and IL1 was dependent on the type of haemodialysis membrane. We also found that Cuprophan induced a reversible decrease of spontaneous and LPS-stimulated production of TNF, IL1 and IL6 during the haemodialysis session. Taken together, these results suggest that Hemophan induced a sustained production of cytokines whereas Cuprophan primed monocytes, probably through the activation of the complement pathway.

Aged↗
PubMed1991

Using ultrapure water in hemodialysis delays carpal tunnel syndrome.

Since 1977, our patients have undergone chronic HD with ultra-pure dialysate (UPD), defined as having endotoxin levels below 0.008 ng/ml and less than 1 bacteria/ml of dialysate. We evaluated the incidence of carpal tunnel syndrome (CTS) in three groups of patients. Group I (GI), 84 patients, dialysed for 6.1 +/- 3.2 years (mean +/- SD) with UPD only; Group II (GII), 39 patients, first dialysed for 3.7 +/- 2.3 years with non-UPD and afterwards for 8.4 +/- 2.1 years with UPD; Group III (G III), 103 patients treated for 6 +/- 5.9 years exclusively with non-UPD. All patients were dialysed with cuprophan or cellulose acetate membranes. Results, expressed by Kaplan-Meier actuarial survival curves as the percent of patients without CTS, show that CTS occurred significantly less in GI than in GIII. This may be due to less stimulation of monocytes resulting from the absence of bacteria, endotoxins and pyrogens in the dialysate, which would reduce the stimulation of cytokines release, interleukin 1 and 6, and tumor necrosis factor, known to stimulate beta 2 microglobulin synthesis.

Actuarial Analysis↗
PubMed1990

Urinary supersaturation with respect to brushite in patients suffering calcium oxalate lithiasis.

The urines of 23 stone-formers presenting repeated calcium oxalate lithiasis and 12 control subjects were collected at six different time periods daily. Supersaturations for calcium oxalate and brushite (DCPD) were calculated using ionic and solubility products. Urines of both groups were supersaturated for calcium oxalate but only urines of the stone-formers were supersaturated for brushite, the most simple calcium phosphate which nucleates very easily at the urinary pH. This fact suggests that the core of the calcium oxalate stone could be made of either a calcium oxalate crystallite or a brushite seed onto which hetergeneous nucleation of calcium oxalate can take place.

Adolescent↗
PubMed1989

[Hypokalemic quadriplegia and coma in renal tubular acidosis].

A case is reported of an acute episode of severe hypokalaemia (K+ = 1.1 mmol.l-1) associated with hyperchloraemic acidosis and simultaneous high urine pH (pH = 7) in a 24 year old woman with type I distal tubular acidosis and nephrocalcinosis. The flaccid paralysis involved the trunk, neck, facial and pharyngeal muscles. She was in areflexic quadriplegia, coma and respiratory failure requiring endotracheal intubation and positive pressure ventilation. There were no cardiac disturbances, presumably because of the chronic potassium depletion, the patient's youth and healthy myocardium. Despite the usually recommended maximal potassium infusion rate (0.25 mmol.kg-1.h-1), there was a transient worsening of her neuromuscular status. Only 12 h later, the first movements were noticed. In order to prevent such a deterioration, a more rapid potassium infusion could have been used. However, in our case, the occurrence of hypokalaemic extrasystoles was reduced and the patient was still intubated and ventilated. It was therefore decided not to run the risk of myocardial inexcitability carried out with supramaximal infusion rates and to keep the usual protocol. Besides, several pitfalls have to be avoided during the treatment of the numerous metabolic disorders coexisting with severe hypokalaemia, such as metabolic acidosis and hyperglycaemia.

Acidosis, Renal Tubular↗
PubMed1989

Aortoiliac reconstruction and renal transplantation: staged or simultaneous.

Aortoiliac atherosclerosis can jeopardize the outcome of renal transplantation. During a five-year period, 176 renal transplants were performed. Of these, four patients underwent prior or simultaneous arterial reconstruction. In two, transplantation was successfully performed three and ten months after abdominal aortic aneurysm repair. In the two others with aortoiliac occlusive lesions, simultaneous arterial reconstruction and transplantation were successfully performed. We conclude that the discovery of aortoiliac lesions in a candidate for renal transplantation warrants consideration for staged or simultaneous arterial reconstruction to widen the indications for transplantation in such individuals and provide satisfactory long-term transplant durability.

Adult↗
PubMed1989

Lack of effect of spiramycin on cyclosporin pharmacokinetics.

1. The influence of spiramycin coadministration on cyclosporin pharmacokinetics was studied in five renal transplant patients. The plasma concentrations of cyclosporin were measured both by non-specific radioimmunoassay (RIA) and high-performance liquid chromatography (h.p.l.c.). 2. The kinetics of cyclosporin were followed before treatment, and after 1 day and then 2 weeks of oral treatment with spiramycin (3 X 10(6) iu, twice daily). The main pharmacokinetic parameters (the area under the plasma drug concentration-time curve, the maximum plasma drug concentration and the time to reach it) obtained both by RIA and h.p.l.c. were not modified by spiramycin cotreatment after 1 day, nor after 2 weeks of spiramycin administration. Therefore, the pharmacokinetics of cyclosporin (parent drug and parent drug plus metabolites) are not influenced by the coadministration of spiramycin macrolide at therapeutic dosage. 3. Spiramycin may be preferable to other macrolide antibiotics known to interact with cyclosporin such as erythromycin or josamycin.

Adolescent↗
PubMed1989

Determination of blood volume in nephrotic patients.

We assessed blood volume (BV) in 20 edematous patients with nephrotic syndrome and in 32 subjects without renal or other disease liable to induce BV variation. Two methods were chosen, one using 131I-albumin and the other 51Cr red blood cells. Among the 20 patients, 11 presented minimal-change lesions, and 9 had histological glomerular impairment. The BV was significantly higher when measured with 131I-albumin in both nephrotic patients and in controls. However, in patients with nephrotic syndrome, the values obtained from the measurement of BV by 131I-albumin showed an increase of only 1%. Comparison of BV values of nephrotic patients and controls showed that BV is equal or higher in two thirds and lower in one third, respectively. The same incidence of histological glomerular lesions was observed in both groups. In conclusion, this study demonstrates that the method using 131I-albumin to measure BV in nephrotic syndrome is reliable. BV is decreased in one third of the patients and is not related to the presence or absence of histological glomerular lesions.

Adolescent↗
PubMed1988

Aluminium overload of parathyroid glands in haemodialysed patients with hyperparathyroidism: effect on bone remodelling.

In the course of chronic renal failure, aluminium may deposit and accumulate in different tissues. The aluminium content of parathyroid glands was measured in 31 haemodialysis patients at the time of a parathyroidectomy. The values were compared with those obtained from ten control patients with primary hyperparathyroidism without renal failure, and were related to bone remodelling. Of the 31 patients, 27 had a bone biopsy after double tetracycline labelling, at the time of parathyroidectomy. Twenty-one patients had severe hyperparathyroidism, three patients had hyperparathyroidism associated with osteomalacia, three patients had mild hyperparathyroidism with reduced bone formation. Seven patients had bone aluminium deposits, associated with osteomalacia in one case. The parathyroid aluminium was 62 +/- 35.7 (mumol/g glandular dry weight) in haemodialysis patients and 14.3 +/- 6.3 in control patients (P less than 0.001). A significant positive correlation existed between parathyroid aluminium and serum aluminium (P less than 0.01). The parathyroid aluminium was not different in the patients with and without bone aluminium deposits. A weak correlation was found between parathyroid aluminium and plasma parathyroid hormone. A significant negative correlation existed between parathyroid aluminium and osteoblastic surfaces (P less than 0.05), but no correlation was found with bone formation rate at tissue and bone multicellular units levels. We conclude that aluminium accumulates in parathyroid glands of dialysed patients. Severe hyperparathyroidism may coexist with aluminium overload of parathyroid glands. A marked aluminium overload, however, may cut short the course of hyperparathyroidism and may decrease parathyroid function and cellular activity in bone.

Adult↗