Characterization of synovial fluid metabolomic phenotypes of cartilage morphological changes associated with osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a multifactorial disease with etiological heterogeneity. The objective of this study was to classify OA subgroups by generating metabolomic phenotypes from human synovial fluid.

DESIGN

Post mortem synovial fluids (n = 75) were analyzed by high performance-liquid chromatography mass spectrometry (LC-MS) to measure changes in the global metabolome. Comparisons of healthy (grade 0), early OA (grades I-II), and late OA (grades III-IV) donor populations were considered to reveal phenotypes throughout disease progression.

RESULTS

Global metabolomic profiles in synovial fluid were distinct between healthy, early OA, and late OA donors. Pathways differentially activated among these groups included structural deterioration, glycerophospholipid metabolism, inflammation, central energy metabolism, oxidative stress, and vitamin metabolism. Within disease states (early and late OA), subgroups of donors revealed distinct phenotypes. Synovial fluid metabolomic phenotypes exhibited increased inflammation (early and late OA), oxidative stress (late OA), or structural deterioration (early and late OA) in the synovial fluid.

CONCLUSION

These results revealed distinct metabolic phenotypes in human synovial fluid, provide insight into pathogenesis, represent novel biomarkers, and can move toward developing personalized interventions for subgroups of OA patients.

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 β2 microglobulin synthesis.

Compromised autophagy precedes meniscus degeneration and cartilage damage in mice

OBJECTIVE

Autophagy is a cellular homeostasis mechanism that facilitates normal cell function and survival. Objectives of this study were to determine associations between autophagic responses with meniscus injury, joint aging, and osteoarthritis (OA), and to establish the temporal relationship with structural changes in menisci and cartilage.

METHODS

Constitutive activation of autophagy during aging was measured in GFP-LC3 transgenic reporter mice between 6 and 30 months. Meniscus injury was created by surgically destabilizing the medial meniscus (DMM) to induce posttraumatic OA in C57BL/6J mice. Levels of autophagy proteins and activation were analyzed by confocal microscopy and immunohistochemistry. Associated histopathological changes, such as cellularity, matrix staining, and structural damage, were graded in the meniscus and compared to changes in articular cartilage.

RESULTS

In C57BL/6J mice, basal autophagy was lower in the meniscus than in articular cartilage. With increasing age, expression of the autophagy proteins ATG5 and LC3 was significantly reduced by 24 months. Age-related changes included abnormal Safranin-O staining and reduced cellularity, which preceded structural damage in the meniscus and articular cartilage. In mice with DMM, autophagy was induced in the meniscus while it was suppressed in cartilage. Articular cartilage exhibited the most profound changes in autophagy and structure that preceded meniscus degeneration. Systemic administration of rapamycin to mice with DMM induced autophagy activation in cartilage and reduced degenerative changes in both meniscus and cartilage.

CONCLUSION

Autophagy is significantly affected in the meniscus during aging and injury and precedes structural damage. Maintenance of autophagic activity appears critical for meniscus and cartilage integrity.

Induction versus noninduction in renal transplant recipients with tacrolimus-based immunosuppression

BACKGROUND

The aim of this study was to compare the efficacy and safety of induction treatment with antithymocyte globulins (ATG) followed by tacrolimus therapy with immediate tacrolimus therapy in renal transplant recipients.

METHODS

This 12-month, open, prospective study was conducted in 15 centers in France and 1 center in Belgium; 309 patients were randomized to receive either induction therapy with ATG (n=151) followed by initiation of tacrolimus on day 9 or immediate tacrolimus-based triple therapy (n=158). In both study arms, the initial daily tacrolimus dose was 0.2 mg/kg. Steroid boluses were given in the first 2 days and tapered thereafter from 20 mg/day to 5 mg/day. Azathioprine was administered at 1-2 mg/kg per day.

RESULTS

At month 12, biopsy-confirmed acute rejections were reported for 15.2% (induction) and 30.4% (noninduction) of patients (P=0.001). The incidence of steroid-sensitive acute rejections was 7.9% (induction) and 22.2% (noninduction)(P=0.001). Steroid-resistant acute rejections were reported for 8.6% (induction) and 8.9% (noninduction) of patients. A total of nine patients died. Patient survival and graft survival at month 12 was similar in both treatment groups (97.4% vs. 96.8% and 92.1% vs. 91.1%, respectively). Statistically significant differences in the incidence of adverse events were found for cytomegalovirus (CMV) infection (induction, 32.5% vs. noninduction, 19.0%, P=0.009), leukopenia (37.3% vs. 9.5%, P<0.001), fever (25.2% vs. 10.1%, P=0.001), herpes simplex (17.9% vs. 5.7%, P=0.001), and thrombocytopenia (11.3% vs. 3.2%, P=0.007). In the induction group, serum sickness was observed in 10.6% of patients. The incidence of new onset diabetes mellitus was 3.4% (induction) and 4.5% (noninduction).

CONCLUSION

Low incidences of acute rejection were found in both treatment arms. Induction treatment with ATG has the advantage of a lower incidence of acute rejection, but it significantly increases adverse events, particularly CMV infection.

TT virus infection in French hemodialysis patients: study of prevalence and risk factors

The TT virus (TTV) is a recently discovered DNA virus which was first identified in patients with non-A to -G hepatitis following blood transfusion. In this study, we tested 150 attendees of two hemodialysis (HD) units of the public hospitals of Marseilles, France, for the presence of TTV genome by using a PCR-based methodology. The overall prevalence of TTV viremia was 28% (compared to 5.3% in blood donors from the same region). We demonstrated the existence of chronic infections and superinfections by strains belonging to different genotypes. The prevalence of infection was higher in patients originating from Africa, in patients with previous blood transfusion or organ transplantation, in patients with antibody to hepatitis B core antigen, and in those with diabetes mellitus. A high prevalence of TTV infection (50%) was also observed in a population of patients with diabetes mellitus but without renal disease. No significant relationship was found between TTV viremia and hepatitis C virus or GB virus C, transaminases, age, sex, and duration of HD treatment. The PCR amplification products (located in open reading frame 1 of the TTV genome) were sequenced. These genomic sequences were submitted to phylogenetic analysis by using the Jukes-Cantor algorithm for distance determination and the neighbor-joining method for tree building. In several instances, sequences from viruses isolated in a HD unit were grouped in the same phylogenetic cluster. These results together with the different distribution of cases in the two HD units suggest there is viral transmission within each.

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.

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.

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.

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.

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.

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.

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.

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.

[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.

[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.

[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.

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.

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.

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.

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.

[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.

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.

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.

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.

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.

[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.

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.

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.

[Vasculorenal accidents in pregnancy. Prognostic value of renal biopsy]

Our study is an attempt to determine whether, after a vasculo-renal accident (VRA) in pregnancy, renal biopsy (RB) is of interest to determining the outcome specially of blood pressure. Starting from the 201 RB we systematically performed in such patients we may conclude: first, the onset of clinical and biological troubles do not allow to postulate the existing kidney lesions. Minimal changes observed in 31 women appeared early 9 times and during the last trimester 22 times. Most of the cases observed were preeclampsia (n = 108). The clinical or biological troubles were observed 44 times within the first months of the pregnancy and in 64 patients at the end of it. A specific group isolated concerns predominant vascular lesions (n = 44). Forward troubles were observed 16 times and 28 times during the third trimester. Second: a follow up has been possible for 1 to 5 years in 145 patients. A permanent hypertension occurred out of the 80 preeclamptic women, meanwhile among the 40 women with predominant vascular lesions, 60 p. 100 developed a permanent hypertension. Thus RB provides interesting data on renal lesions revealing sometimes (n = 18) a specific nephropathy (most of them were a glomerulopathy). Furthermore predominant vascular lesions suggest hypertension to recur in later pregnancy or become permanent.

Clinical correlation between hypercoagulability and thrombo-embolic phenomena

A study of the coagulolytic balance as well as platelet aggregation was carried out in 64 nephrotic patients. The data were correlated, in a prospective attempt, with the clinical demonstration of thrombo-embolic events. Activating factors (factors I, VIIIc, VIIIr:Ag) were increased as well as certain clotting inhibitors, alpha-1-antitrypsin and alpha-2-macroglobulin. There was a platelet hyperaggregability in 31.5% of our patients. Thrombo-embolic complications occurred in six subjects (9%). The data of these six patients were compared with that of the other patients; no significant correlation were found between clotting abnormalities and thrombosis. Low level of ATm (less than 0.8 U.Fr) and severe hypoalbuminemia (less than 20 g/liter) were of no predictive value for the occurrence of thrombo-embolic events.