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Biomedical subjects

M Olmer

Publications and source records attributed to M Olmer.

At least 19 recordsLinked to original sources
PubMed1998

Long-term nonprogressive human immunodeficiency virus-1 infection in a kidney allograft recipient.

We report a unique case of a renal transplant patient with a long-term nonprogressive human immunodeficiency virus type-1 (HIV-1) infection and who is asymptomatic despite sustained immunosuppression. Renal function is normal, and HIV infection was probably acquired through blood transfusion before the transplant. Nonprogression may be due either to an effective immune control of HIV replication or to particular genetic aspects of the virus. Several virological investigations were carried out to verify if she is infected with an attenuated virus strain. Results show an unusual combination of high and stable CD4 count, ongoing viral replication and elevated viral loads. Attempts to isolate the virus from plasma were unsuccessful, but isolation was possible from peripheral blood mononuclear cells, and the virus was shown to be non-syncytium-inducing. Sequence analysis of the nef gene revealed no mutation. This exceptional lack of progression of HIV infection under immunosuppressive therapy requires further investigation.

Adult↗
PubMed1998

A new approach to evaluate vascular access in hemodialysis patients.

We evaluated the importance of vascular access in hemodialysis patients using noninvasive methods with the Transonic Systems monitor in 108 patients. Most of these patients (84%) had native vein fistulas. We found that a blood flow rate of below 500 ml/min suggested the occurrence of vascular stenosis and justified confirmation by angiography. Increased recirculation could be evaluated readily and was detected in only 10% of patients. Finally, employing the evaluation of the Kt/V index, we found a good correlation between low flux through the fistula and a low Kt/V value.

Adult↗
PubMed1997

Preliminary evidence for a role of apolipoprotein E alleles in identifying haemodialysis patients at high vascular risk.

Conventional risk factors have very low predictive power in identifying haemodialysis patients at high risk of vascular accidents. A role for apolipoprotein E isotypes was looked for in a small, but rigorously defined, cohort of longterm haemodialysis patients. In individuals with high vascular risk, as identified by higher common carotid intima/media thickness, we found an excess of apolipoprotein E4 alleles. This preliminary result requires confirmation in large patient cohorts.

Adult↗
PubMed1997

Transmission of the hepatitis C virus in an hemodialysis unit: evidence for nosocomial infection.

Hepatitis C virus (HCV) infection is a frequent feature in hemodialysis (HD) patients. The way of viral transmission is difficult to establish, but in previous studies the role of blood transfusions and of HD treatment duration, and the possibility of nosocomial transmission of the virus have been suggested. We present here the results of a virological follow-up of HCV infection in our HD unit in 1993-1994, and a molecular study of viral strains that led to a possible reconstruction of viral spreading. All patients in our unit were regularly tested for alanine aminotransferase, HCV antibodies and HCV RNA in serum. Seven seroconversions were detected during follow-up, and a high proportion of type 1b HCV strains was found in infected patients. Nucleotide sequences located in the envelope 1 (E1) viral coding region of type 1b strains were compared in our patients and numerous controls infected with the same HCV genotype. A high proportion of patients with antibodies to HCV were detected in our unit (32.5%). Blood transfusions and duration of HD treatment were risk factors for HCV infection. Seroconversions in patients never transfused and predominance of type 1b HCV strains suggested that infection had occurred via the nosocomial pathway in our unit. Similar sequences in the E1 region were found in four patients treated, forming a distinct cluster in a phylogenetic tree. Of these four patients, two had been infected before 1991, and the others made a seroconversion for HCV at the same period in 1994. In all other patients, including a nurse who had been in charge of some infected patients, distinct strains were found. Duration of HD treatment seems to be a major factor of risk for HCF infection in HD units. Contamination could occur during blood transfusion or via the nosocomial pathway through a crossinfection mechanism from patients already infected. The latter mechanism was formally demonstrated in this study.

Adolescent↗
PubMed1996

Nosocomial transmission of hepatitis C virus in haemodialysis patients.

A systematic virological follow-up of 114 haemodialysis patients treated in the same unit showed that 37, including 17 PCR positive patients, were seropositive for hepatitis C virus (HCV). Type 1b HCV was detected in 10 patients and was much more frequent in this population than in the whole population of patients treated in the hepatogastroenterology departments in southeastern France. The E1/E2 genomic region of seven type 1b HCV strains was sequenced. In four patients, a similar strain was detected in both the E1 variable region and the E2 hypervariable region (HVR1). In addition, two of these four patients were seronegative and PCR negative at the beginning of the study and had not been transfused or transplanted during this period. A phylogenetic tree was drawn which confirmed that these strains were very similar and showed that HCV was transmitted via the nosocomial pathway in this haemodialysis unit.

Adolescent↗
PubMed1996

Monocyte production of transforming growth factor beta in long-term hemodialysis: modulation by hemodialysis membranes.

Cytokines are likely involved in hemodialysis-associated complications such as immunodeficiency and beta 2 microglobulin amyloidosis. Because transforming growth factors beta (TGF beta) exert immunosuppressive effects on lymphocytes, down-modulate monocyte functions, and promote fibrosis, we hypothesize that they participate in the deleterious effects of hemodialysis. We investigated the production of TGF beta 1 and TGF beta 2 by monocytes from controls and patients dialyzed with high-flux cellulose triacetate (CT) and polyacrylonitrile (PAN) membranes. The detection of both TGF beta s required an acidification step, suggesting that they are secreted as latent complexes. The spontaneous production of TGF beta 1 and TGF beta 2 was significantly higher in patients dialyzed with CT or PAN than in controls, but the oversecretion of TGF beta 1 was more sustained in CT-treated patients than in PAN-dialyzed patients. The production of interleukin-6 (IL-6) was increased in both patient groups as compared with controls. In contrast to TGF beta 1, the increase was greater in PAN-treated patients than in CT-treated patients, and the release of tumor necrosis factor alpha (TNF alpha) was increased only in PAN-treated patients. Taken together, our results show that hemodialysis is associated with the oversecretion of monocyte cytokines. Moreover, the type of dialysis membrane specifically affects the balance between the secretion of suppressive cytokines such as TGF beta and that of inflammatory cytokines such as IL-6 and TNF alpha.

Acrylic Resins↗
PubMed1996

Transplantation of a horseshoe kidney into 2 recipients.

We report the case of a transplantation of a horseshoe kidney to 2 recipients after isthmic section of the kidney. A review of the literature since 1975 mentions only 14 cases of transplantation of a horseshoe kidney. In the absence of a significant urological clinical history of the donor, the presence of a horseshoe kidney, in the case of multiorgan harvesting, does not represent a contraindication for transplantation.

Adult↗
PubMed1995

[Renal complications from intravenous immunoglobulins. Role of renal hemodynamic factors].

In idiopathic thrombocytopenic purpura, intravenous immunoglobulin therapy is currently a treatment of choice. It is usually effective with little side-effects. Acute renal failure has been recently identified as a potential, though rare, complication of intravenous immunoglobulins. However, the mechanism remains unclear. A 53 year-old-woman with idiopathic thrombocytopenic purpura developed oliguric renal failure after high doses of intravenous immunoglobulins. Her renal function returned to normal after dialysis and plasmapheresis. This rapid normalization suggested that acute renal failure was functional. Since laboratory tests showed an increase in protidemia concomitant to the immunoglobulin therapy, acute renal failure was likely to be related to hyperosmolar renal damage.

Acute Kidney Injury↗
PubMed1995

[Goodpasture syndrome: role of an epidemiological factor? Apropos of two cases].

Goodpasture's syndrome is a rare pneumorenal syndrome. Although the antigenic target of this auto-immune disorder is now known, its etiology remains debated. We report two cases of Goodpasture's syndrome occurring in similar epidemiologic conditions concerning the moment the disease began, the age and sex of the patients, their place of residence and work and manipulation of chemicals. Thus, a common environmental factor could have been the trigger event of the Goodpasture's syndrome. The epidemiologic features of this disease are reviewed.

Adult↗
PubMed1995

High-affinity interaction of long-chain fatty acids with serum albumin in nephrotic syndrome.

1. We have examined the effect of hypoalbuminaemia, a hallmark of nephrotic syndrome, on the albumin-fatty acid equilibrium in the plasma of 11 adult patients with nephrosis compared with 12 healthy subjects and six subjects with normoalbuminaemic hyperlipoproteinaemia. 2. We used a dialysis exchange rate method which allows the evaluation in relative terms of the binding affinity of albumin for plasma fatty acid and the fatty acid availability, tentatively equated with the unbound fatty acid fraction. 3. In nephrotic patients, an increase (P < 0.001) in albumin affinity for fatty acid was seen compared with healthy subjects, which was negatively correlated with albuminaemia (r = -0.69, P < 0.02). No change in fatty acid availability was seen for the group as a whole, but individual values showed a wide scatter, with the highest values in four patients with the highest fatty acid-albumin molar ratios. The increase in albumin affinity for fatty acid was specific to nephrotic syndrome since no such effect was seen in subjects with hyperlipoproteinaemia, who only showed a moderate increase (P < 0.01) in fatty acid availability. 4. The increased albumin affinity for fatty acid in nephrotic syndrome supports the hypothesis that an albumin component with lower affinity for fatty acid might filter out through the diseased glomerular membrane and leave the high-affinity albumin in plasma.

Adolescent↗
PubMed1995

Serum erythropoietin and reticulocyte maturity index after renal transplantation: a prospective longitudinal study.

Improvement in erythropoiesis following renal transplantation (RT) was assessed in 74 consecutive patients by serial measurements of serum erythropoietin (EPO), hematocrit, absolute reticulocyte count (ARC) and serum creatinine during the first month after RT. The reticulocyte maturity index (RMI) which provides an objective measure of red-cell maturity was assessed in 31 patients by flow cytometry using thiazole orange. In group I (n = 39) with immediate graft function, EPO levels increased rapidly from day 2 and remained elevated at the plateau between two and three times the upper limit of normal during the first 2 months. In group II (n = 29) with delayed graft function, EPO levels increased gradually from day 10 when renal function improved significantly. No particular significant biphasic pattern of secretion was detected in group I or II. In both groups, hematocrit rose to over 35% approximately 3 months after RT. In a third group (n = 6) with immediate postoperative acute blood loss and severe anemia, a hematocrit fall was followed by a steep increase in EPO levels with a negative correlation between hematocrit and EPO levels during the first 4 days. During acute rejection, EPO diminished significantly by more than 50% either on the day of diagnosis or on the following days in 8 patients. RMI increased by 25% over the pretransplantation values by 7 days on average before the ARC rose. Thus the RMI seems to be an early sensitive predictor of erythropoiesis after RT. EPO response after RT depends on graft function, and the early transient increase in EPO observed in patients with acute blood loss may explain the apparent biphasic response previously reported.

Adolescent↗
PubMed1995

[Outcome of kidney transplants with multiple arteries].

OBJECTIVES: To evaluate the morbidity of multiple artery renal transplants (> 1 artery) and to assess the value of this parameter as a risk factor for complications of renal transplantation in adults. METHODS: 140 renal transplants derived from brain dead donors with multiple arteries (2 arteries = 123, 3 arteries = 17) were reviewed with a mean follow-up of 3 years (6-120 months). Pedicle restoration was performed in 57 cases (end-to-side reimplantation of a polar artery = 17, composite aortic patch graft = 14, multiple procedures = 10, ligation of a polar artery = 8, arterial wound = 5, "gun barrel" anastomosis of 2 arteries = 4). Arteriography was performed systematically in 57 cases, in the absence of any signs suggestive of a vascular complication. RESULTS: 2 recipients died from a vascular complication. 40% of transplants were functional at 5 years. 10 transplantectomies were performed for a vascular complication. 14 recipients returned to dialysis because of a vascular complication. 7.5% of systematic arteriographies revealed stenosis of the transplant artery. 54 transplants developed a vascular complication: thrombosis = 19, stenosis = 25. Three-artery transplants had a vascular morbidity of 50%. "Gun-barrel" anastomoses and polar reimplantations into the main trunk had a vascular morbidity of 40%. The urological morbidity was 10%. CONCLUSION: Multiple artery renal transplants, especially 3-artery transplants and certain pedicle restorations, are associated with a high risk of vascular complications. Arterial anatomy is a selection criterion for the donor and recipient which must be taken into account in renal transplantation.

Adolescent↗
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↗