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Biomedical subjects

M J Kemper

Publications and source records attributed to M J Kemper.

At least 19 recordsLinked to original sources
PubMed2002

Type I IgE receptor, interleukin 4 receptor and interleukin 13 polymorphisms in children with nephrotic syndrome.

Polymorphisms in the genes encoding the high-affinity IgE receptor, the interleukin 4 (IL4) receptor and IL13 can be associated with the development of asthma and allergy. Although several studies have described an association between atopy and idiopathic childhood nephrotic syndrome (NS), it is not clear whether this association is of a causal nature. Furthermore, it is not known whether these polymorphisms are associated with the clinical course of NS. A total of 84 children (52 male and 32 female; mean age 12.1 years) with NS were included in the present study. Of these, 78 could be classified as either atopic or non-atopic. Atopy was defined by elevated IgE levels (>100 k-units/l) and/or a positive history of atopy (33 of 78 patients). DNA was extracted from blood collected in EDTA tubes, and polymorphisms at positions 50 and 551 of the IL4 receptor, position 110 of IL13 and position 181 of the high-affinity IgE receptor were investigated by sequence-specific PCR or direct sequencing. Although we noted a strong tendency towards a higher allele frequency of polymorphisms in children with atopy and NS compared with children with NS but without atopy (IL4 50, 30% compared with 18%; IL4 551, 39% compared with 31%; IL13 110, 45% compared with 33%; IgE 181, 12% compared with 13%), these differences did not reach statistical significance. There were no differences in the frequency of polymorphisms between the different clinical courses of NS (frequent relapsers, steroid-dependent or steroid-resistant NS). We conclude that polymorphisms in the IL4 receptor, the high-affinity IgE receptor and IL13 do not seem to predict the clinical course of NS, despite the fact that serum IgE elevations are more frequent in patients with NS than in normal control subjects. The investigated polymorphisms may contribute to the IgE switch in patients with NS.

Adolescent↗
PubMed2001

Th2 cytokine profile in infants predisposes to improved graft acceptance after liver transplantation.

BACKGROUND: The T helper cell type 1 (Th1) cytokines interleukin (IL)-2 and interferon (IFN)-gamma are mediators of acute graft rejection after liver transplantation and Th2 cytokines, such as IL-4 and IL-10, may have a protective role and correlate with graft acceptance. To test the hypothesis that infants aged <1 year have an immunological advantage with regard to graft acceptance because of a partially immature immune system with a physiological balance toward a Th2 cytokine profile, we conducted the present study. METHODS: We compared the T helper serum cytokine profiles in 105 infants and children after liver transplantation with or without acute graft rejection and analyzed the normal age-distributed concentrations of T helper cytokines in 51 healthy controls. RESULTS: The incidence of acute graft rejection was as follows: 0 to 12 months, 26.8%; 1 to 3 years, 40.0%; and >3 years, 71.8%. There was a significantly lower incidence of acute rejection in infants 0 to 12 months of age compared with children >1 year (11/41 vs. 38/64; P=0.001). In healthy infants, significant increasing Th1 cytokine concentrations and decreasing Th2 cytokine concentrations were found with increasing age. Patients with acute rejection had significantly higher values of Th1 cytokines compared with nonrejecting subjects, who had significantly higher concentrations of Th2 cytokines. A longitudinal analysis of serum cytokines from patients showed that changes of the cytokine patterns in the follow-up did not differ significantly from preoperative values, except in the 4 weeks posttransplant. CONCLUSIONS: We conclude from the data that the physiological balance toward a Th2 cytokine profile of infants in the first months of life predisposes to improved graft acceptance. Transplantation of children with biliary atresia as early as possible, avoiding Th1 stimulation by recurrent infections and vaccinations, may have a positive impact on overall tolerance.

Acute Disease↗
PubMed2001

B-cell dysfunction and depletion using mycophenolate mofetil in a pediatric combined liver and kidney graft recipient.

The use of mycophenolate mofetil (MMF) in combination with cyclosporin A (CsA) and steroids is well established after kidney transplantation (Tx) in children. A 9-yr-old girl with primary hyperoxaluria type 1 and systemic oxalosis underwent a combined kidney and liver Tx at our institution. The post-operative immunosuppression consisted of CsA, prednisolone, and MMF. Four weeks post-transplant the girl suffered from a severe urinary tract infection caused by Pseudomonas aeruginosa, when the serum immunoglobulin G (IgG) concentration was found to be critically low (<1.53 g/L). Additionally, there was an isolated B-cell depletion (240/microL) at that time. In the following course, the B-cell count was significantly diminished until the MMF was stopped 13 weeks post-transplant. As a result of the very low serum IgG concentration, intravenous immunoglobulin (IVIG) substitution was necessary. There was no significant loss of immunoglobulins in the ascites and urine and no other medication with possible side-effects on B cells was given. We suggest that MMF can lead to suppressed IgG production by B cells and can cause a defective differentiation into mature B cells. In vitro studies demonstrated these effects of MMF on B cells, but no in vivo cases of this phenomenon have been reported. B-cell counts and serum IgG concentrations returned to normal values after discontinuing the MMF. As we can assume that the observed B-cell dysfunction and depletion were MMF related, we suggest that serum IgG concentrations should be monitored when MMF is used after solid-organ Tx.

B-Lymphocytes↗
PubMed2001

Bone mineral density in children with primary hyperoxaluria type I.

BACKGROUND: In primary hyperoxaluria type I (PH 1), hepatic overproduction of oxalate leads to its deposition in various organ systems including bone (oxalosis). To evaluate skeletal status non-invasively in PH 1 we measured bone mineral density (BMD). METHODS: Peripheral quantitative computed tomography of the distal radius was performed in 10 children with PH 1 (mean chronological age 9+/-3.1, mean skeletal age 8.3+/-3.0 years): seven were on conservative treatment (CT) including one patient after pre-emptive liver transplantation (PH1-CT) and three were studied with end-stage renal disease on peritoneal dialysis (PH1-ESRD). RESULTS: Mean trabecular bone density (TBD) was significantly increased in PH1-ESRD compared with both age-matched healthy and uraemic controls (65227 vs. 168+/-63 and 256+/-80 mg/cm(3); P<0.002 and P<0.007, respectively), while cortical bone density (CBD) was elevated to a lesser degree (517+/-23 vs. 348+/-81 vs. 385+/-113 mg/cm(3); P<0.02 and P<0.04, respectively). In PH 1, CBD and, even more so, TBD were significantly correlated with serum creatinine (r=0.91 and r=0.96, P<0.0001, respectively) and plasma oxalate levels (r=0.86 and r=0.94, P<0.001 and P<0.0001, respectively). In children with PH 1 and normal glomerular function, both CBD and TBD were comparable with healthy controls. CONCLUSION: These preliminary data suggest that in PH 1 BMD is significantly increased in ESRD, probably due to oxalate disposal. Measurement of BMD may be a valuable and non-invasive tool in determining and monitoring oxalate burden in this disorder.

Bone Density↗
PubMed2001

Renal function in congenital anomalies of the kidney and urinary tract.

Congenital anomalies of the kidneys and urinary tract are a major cause of chronic and end-stage renal failure in children. The molecular mechanisms having been elaborated, there is now growing evidence that kidney function is to a large extent determined genetically at an early stage. Assessment of kidney function is an important tool in clinical medicine and is feasible in utero. Postnatally, determination of absolute glomerular filtration rate and also of split and excretory renal function play an important role in the determination of treatment and prognosis. This is supplemented by other biochemical, molecular and interventional prognostic factors, which are of help in preservation of kidney survival by minimizing modulating factors. If chronic or terminal renal failure ensues in childhood or even in early infancy, however, improved medical care has led to encouraging results, ultimately influencing the motivation in the care of children with congenital anomalies of the kidney and urinary tract.

Child↗
PubMed2001

Antenatal oligohydramnios of renal origin: postnatal therapeutic and prognostic challenges.

Urinary tract anomalies (UTA) including polycystic kidney disease nowadays can be detected antenatally by ultrasound. The concomitant presence of oligohydramnios has been regarded as a severe risk factor for renal dysfunction and pulmonary hypoplasia, although clinical data after birth are scarce. We report the postnatal course and long-term follow-up of 10 infants with oligohydramnios due to congenital UTA from two pediatric nephrology centers. The underlying final diagnoses were autosomal-recessive polycystic kidney disease (ARPKD, n = 2), familial tubular dysgenesis (n = 2) and bilateral renal hypoplasia (n = 6) including 3 children with posterior urethral valves. Two children died in the neonatal period while 8 children are currently alive at a median age of 2.5 (range 1.1-10) years. In the postnatal period, respiratory failure necessitating mechanical ventilation occurred in 7 infants (including the 2 non-survivors). All surviving children had chronic renal failure, which could be managed conservatively in 6 children (median GFR 45 (range 15-53) ml/min/1.73 m2) while 2 reached end-stage renal disease; one undergoing preemptive kidney transplantation and one peritoneal dialysis. Seven of 8 children reached normal developmental milestones. In conclusion, the presence of antenatal oligohydramnios in infants with UTA does not always carry a poor prognosis. The high incidence of perinatal complications, the complexity of underlying causes and the prevalence of postnatal chronic renal dysfunction calls for a multidisciplinary approach in the management of these children.

Female↗
PubMed2000

Unfavorable response to cyclophosphamide in steroid-dependent nephrotic syndrome.

Development of steroid dependency represents a significant therapeutic challenge in steroid-sensitive nephrotic syndrome. Previous studies have shown conflicting results concerning the benefit of a 12-week treatment with cyclophosphamide (CPO), with 24%-67% of patients achieving long-term remission. We therefore analyzed the clinical response of 20 consecutive children with steroid-dependent nephrotic syndrome (SDNS) (12 male, median age at start of treatment 5.9 years, range 3.2-14.7 years) treated at our institution with CPO (2 mg/kg per day) for 12 weeks since 1989. Median duration of follow-up was 5.8 (range 1.1-9.25) years. Only 6 of 20 children (30%) showed a long-term remission of >2 years, while 14 of 20 (70%) developed relapses again. Of these, 12 patients (86%) again developed steroid dependency, requiring further alternative treatment. Our data show that a 12-week course of CPO leads to unfavorable results in the majority of patients with SDNS. We therefore conclude that there is a need for further optimization of therapy in SDNS.

Child↗
PubMed2000

Long-term results of pre-emptive liver transplantation in primary hyperoxaluria type 1.

In primary hyperoxaluria type 1 (PH 1), deficiency or mistargeting of hepatic alanine glyoxylate aminotransferase (AGT) results in over-production of oxalate and hyperoxaluria, leading to nephrocalcinosis and development of end-stage renal disease (ESRD) in the majority of patients. Renal transplantation (Tx) alone carries a high risk of disease recurrence as the metabolic defect is not cured. Therefore, combined liver/kidney Tx is recommended for patients with ESRD. An alternative approach is to cure PH 1 by pre-emptive isolated liver Tx (PLTx) before ESRD has occurred, but this approach has been carried out only occasionally and there are no uniformly accepted recommendations concerning the timing of this procedure. We report follow-up 3-5.7 yr after performing successful PLTx in four children (at the age of 3-9 yrs) with PH 1 prior to the occurrence of ESRD (glomerular filtration rate [GFR] range 27-98 mL/min/1.73 m2). There was no mortality or long-term morbidity associated with the Tx procedure. Plasma and urinary oxalate levels normalized rapidly within 4 weeks, and renal function did not deteriorate under immunosuppression, even in one patient with advanced chronic renal failure (GFR 27 mL/min/1.73 m2) who showed a stable course for more than 5.7 yrs. Although treatment must be individualized in this severe metabolic disorder, and PLTx has to be regarded as an invasive procedure, we consider that PLTx should be offered and considered early in the course of PH 1. PLTx cures the metabolic defect in PH 1 and can help to prevent, or at least delay, the progression to ESRD and systemic oxalosis.

Acute Kidney Injury↗
PubMed1999

Plasma calcium oxalate supersaturation in children with primary hyperoxaluria and end-stage renal failure.

BACKGROUND: Children with primary hyperoxaluria type 1 (PH 1) are at great risk to develop systemic oxalosis in end-stage renal disease (ESRD), as endogenous oxalate production exceeds oxalate removal by dialytic therapy. As oxalate accumulates, calcium oxalate (CaOx) tissue deposition occurs. Children with other causes of ESRD, however, are not prone to CaOx deposition despite elevated plasma oxalate (POx) levels. METHODS: Our study objective was to examine the potential mechanisms for these observations. We measured POx, sulfate, citrate, and calculated CaOx saturation (betaCaOx) in 7 children with ESRD caused by PH 1 and in 33 children with non-PH-related ESRD. Maintenance hemodialysis (HD) was performed in 6 PH 1 and 22 non-PH patients: Pre- and post-HD levels were analyzed at this point and were repeated twice within 12 months in 5 PH 1 and 14 non-PH patients. Samples were obtained only once in 12 patients (one PH 1) on peritoneal dialysis (PD). After liver-kidney or kidney transplantation, plasma levels were measured repetitively. RESULTS: The mean POx was higher in PH 1 (125.7 +/- 17.9 micromol/liter) than in non-PH patients (44.2 +/- 3.3 micromol/liter, P < 10(-4)). All other determined anions did not differ between the two groups. betaCaOx was higher in PH 1 (4.71 +/- 0.69 relative units) compared with non-PH children (1.56 +/- 0.12 units, P < 10(-4)). POx and betaCaOx were correlated in both the PH 1 (r = 0.98, P < 2 x 10(-4)) and the non-PH group (r = 0.98, P < 10(-4)). POx and betaCaOx remained stable over time in the non-PH children, whereas an insignificant decline was observed in PH 1 patients after six months of more aggressive dialysis. betaCaOx was supersaturated (more than 1) in all PH 1 and in 25 out of 33 non-PH patients. Post-HD betaCaOx remained more than 1 in all PH 1, but in only 2 out of 22 non-PH patients. In non-PH children, POx and betaCaOx decreased to normal within three weeks after successful kidney transplantation, whereas the levels still remained elevated seven months after combined liver-kidney transplantation in two PH 1 patients. CONCLUSION: Systemic oxalosis in PH 1 children with ESRD is due to higher POx and betaCaOx levels. As betaCaOx remained supersaturated in PH 1 even after aggressive HD, oxalate accumulation increases, and CaOx tissue deposition occurs. Therefore, sufficient reduction of POx and betaCaOx is crucial in PH 1 and might only be achieved by early, preemptive, combined liver-kidney transplantation or liver transplantation alone.

Bone and Bones↗
PubMed1999

Iron homeostasis in relapsing steroid-sensitive nephrotic syndrome of childhood.

AIM: Urinary transferrin loss is a typical feature in relapse of the idiopathic nephrotic syndrome, however, the impact on serum iron homeostasis and hematological parameters has not been studied systematically so far. PATIENTS AND METHODS: Therefore, we investigated serum iron (Fe), erythropoietin (EPO), ferritin (FN), transferrin (TF), total iron-binding capacity (TEBK), transferrin saturation and the soluble transferrin receptor (sTFR) combined with hematological parameters (hemoglobin, MCV, MCH) in 42 children with relapsing, steroid-sensitive nephrotic syndrome (NS) in remission (RM, n = 26) and relapse (RL, n = 16), including 13 patients who were studied in both states. Thirty-three age-matched healthy children served as controls. RESULTS: Fe, TEBK and TF were significantly reduced in RL compared to RM in cross-sectional as well as in paired studies while ferritin, hematological parameters and EPO levels remained unchanged. A significant increase, however, of the soluble transferrin-receptor could be demonstrated in cross-sectional analysis comparing RL to RM and healthy controls (3568+/-713 mg/ml vs 2625+/-576 vs 2646+/-697; p < 0.001 respectively) as well as in paired analysis of 13 patients in RL and RM (p < 0.001). CONCLUSION: We conclude that transient transferrin and iron deficiency occurs in RL of INS but this seems to be counterbalanced by upregulation of the sTFR, a mechanism that might be important in preventing the development of iron deficiency anemia during the active nephrotic state.

Adolescent↗
PubMed1998

[The treatment with levamisole of frequently recurring steroid-sensitive idiopathic nephrotic syndrome in children].

BACKGROUND AND OBJECTIVE: The treatment of frequently relapsing steroid-sensitive nephrotic syndrome in children with established immunosuppressive drugs (steroids, cyclophosphamide, cyclosporin A) sometimes presents problems because of the expected incidence of side effects. Stimulation of the immune system with the anthelminthic drug levamisole in this disease has been documented. Aim of this study was to assess in a prospective but uncontrolled series of observations its value and side effects. PATIENTS AND METHODS: 25 patients (15 boys, ten girls; median age 10 [3.5-22] years) were given levamisole, 2 mg/kg/48 h. Before this treatment was started eight of the children/adolescents (32%) had frequent relapses and 17 (68%) had become steroid-dependent. Treatment was started during steroid-induced remission and continued for 3-24 (median 6) month, while steroids were discontinued after four weeks. RESULTS: Relapse frequency per patient month was reduced from a mean of 0.5 (0.33-0.83) before to 0.31 (0-0.67) during levamisole administration (P < 0.001). In 12 patients (48%) no or considerably fewer relapses were observed. Patients with exclusively frequent relapses responded to levamisole better than those with steroid dependence (7/8 [87.5%] vs. 5/18 [27.7%], P = 0.01). Side effects were reversible leukopenia in two patients and nonspecific skin rash as well as epigastric pain in one patient. CONCLUSION: Levamisole is an efficacious addition or alternative, with a low incidence of side effects, in the treatment of frequently relapsing nephrotic syndrome, particularly so in yet steroid-dependent patients.

Adjuvants, Immunologic↗
PubMed1998

Plasma calcium-oxalate saturation in children with renal insufficiency and in children with primary hyperoxaluria.

BACKGROUND: Calcium-oxalate (CaOx) deposition and systemic oxalosis are uncommon in children with chronic renal failure (CRI), but frequent in children with primary hyperoxaluria type I (PH-1). We hypothesized a difference in plasma CaOx saturation (betaCaOx) and its determining factors would explain this discrepancy. METHODS: Therefore, in addition to common biochemical measurements, plasma-oxalate (POx), citrate (PCit) and sulfate (PSulf) (plasma anions) were measured and betaCaOx was calculated in 17 PH-1 patients with normal renal function receiving pyridoxine and citrate therapy, in 54 children with CRI (SCr 0.9 to 5.9 mg/dl), and in 50 healthy children (NL). Plasma anions were analyzed by ion-chromatography and betaCaOx was calculated using a PC-based program for solution equilibria. RESULTS: Compared to NL, all plasma anion levels and betaCaOx were higher in PH-1 and CRI; POx, PCit and betaCaOx were higher in PH-1 than in CRI (P < 0.05), but PSulf was higher in CRI (P < 0.01). BetaCaOx and POx were correlated in all groups (r = 0.63 to 0.95, P < 10(-4)). POx and betaCaOx were both inversely correlated to a decrease in GFR in CRI patients. PCit and PSulf did not influence betaCaOx. Although supersaturation (betaCaOx > 1) was found in 7 CRI and in 4 PH-1 patients, eye examinations were suspicious for CaOx depositions only in the PH-1 patients, while systemic oxalosis was confirmed in one PH patient because of oxalate osteopathy. CONCLUSIONS: In PH-1, POx and betaCaOx are elevated even with normal renal function, which increases the likelihood of CaOx crystal deposition. Therefore, more effective therapy to decrease betaCaOx is crucial to reduce the risk of systemic oxalosis. In children with CRI unknown, but presumably protective substances, help prevent the risk of systemic oxalosis, despite increased POx and betaCaOx levels, often to supersaturation levels.

Calcium Oxalate↗
PubMed1998

Simultaneous determination of oxalate, citrate and sulfate in children's plasma with ion chromatography.

To improve our understanding of both diagnosis and treatment of diseases of oxalate metabolism, we first set out to establish a new ion-chromatographic method to determine normal plasma levels of oxalate, citrate and sulfate from single plasma samples. In 50 infants and children (23 girls, 27 boys, aged 0.2 to 17 years) with normal renal function, blood was drawn in Li-heparin tubes, placed on ice and preserved immediately with 40 microliters M HCl/ml plasma in two ultracentrifugation steps. For measurement, plasma was injected onto an ion chromatography system with NaOH as the mobile phase, and then run as a linear gradient from 5 mM to 52.5 mM over 21 minutes. Analysis yielded measurable and reproducible oxalate (6.43 +/- 1.06 microM/liter), citrate (79.3 +/- 27.4 microM/liter) and sulfate (235.0 +/- 85.3 microM/liter) levels, without any age and gender specific differences. The least detectable plasma oxalate level was < 0.3 microM with a high reliability and reproducibility (coefficient of variance 1.95 to 4.75%). In conclusion, we established a reproducible, precise method to determine the relevant plasma anions involved in mineral metabolism, which heretofore have not been easily measurable. Studies of diseases of oxalate and citrate metabolism are ongoing on the basis of the normal plasma values achieved in this study.

Adolescent↗
PubMed1997

Primary hyperoxaluria type 2.

UNLABELLED: Primary hyperoxaluria type 2 (PH2) is a rare disease with only 24 patients reported in the literature so far. It should be considered in any patient presenting with urolithiasis or nephrocalcinosis due to hyperoxaluria. The metabolic defect is deficiency of D-glycerate dehydrogenase/glyoxylate reductase leading to characteristic hyperoxaluria and excretion of L-glycerate, the cornerstone of diagnosis of PH 2. Although development of terminal renal failure seems to be less prevalent than in PH 1, recent reports indicate that chronic as well as terminal renal insufficiency may occur. Therefore specific therapeutic measures should aim at reduction of urinary calcium oxalate saturation by potassium citrate or pyrophosphate to reduce the incidence of nephrolithiasis and nephrocalcinosis and thus improve renal survival. Secondary complications (obstruction, urinary tract infections and pyelonephritis) must be avoided. In patients with terminal renal failure isolated renal transplantation seems to carry a high risk of disease recurrence. CONCLUSION: PH 2 is a rare but important cause of urolithiasis and nephrocalcinosis; long-term follow up is necessary, since the renal prognosis may be worse than previously anticipated.

Humans↗