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Biomedical subjects

M Fischbach

Publications and source records attributed to M Fischbach.

At least 19 recordsLinked to original sources
PubMed1996

Gitelman's syndrome is genetically distinct from other forms of Bartter's syndrome.

In the past the term Bartter's syndrome has been used to describe a spectrum of inherited renal tubular disorders with hypokalemic metabolic alkalosis and overlapping and additional clinical and biochemical features. Pathogenesis remained uncertain until recently Gitelman's syndrome, the hypokalemic-hypomagnesemic variant with hypocalciuria, was linked to the gene encoding the thiazide-sensitive Na-Cl-cotransporter (TSC) located on chromosome 16q. Various mutations in the TSC gene were identified in patients with Gitelman's syndrome. To clarify whether different forms of hypokalemic tubular disorders (HTD) represent variable phenotypes of a common genetic defect, we performed linkage analyses in 17 families with different symptoms of HTD with four highly polymorphic chromosome 16 DNA markers closely linked to the TSC gene. Linkage of Gitelman's syndrome to the TSC locus was confirmed in our families with a maximum two-point Lod score Z = 4.70 (theta = 0.001) for marker locus D16S526. Highly negative LOD scores were obtained at this locus in our families with classic Bartter's syndrome (Z = 9.89, theta = 0.001) and hyperprostaglandin E syndrome (Z = -11.24, theta = 0.001). Our data prove that Gitelman's syndrome is genetically distinct from classic Bartter's syndrome and hyperprostaglandin E syndrome. It remains unknown if classic Bartter's syndrome and hyperprostaglandin E syndrome are caused by a common genetic defect.

Adolescent↗
PubMed1996

Risk factors for chronic rejection in pediatric renal allograft recipients.

To determine the risk factors predictive of graft loss from chronic rejection in pediatric renal allograft recipients, we reviewed the collaborative study database of the Société de Néphrologie Pédiatrique which registered 314 grafts from January 1987 to December 1991. Of the 289 grafts analyzed, 71 failed during follow-up, chronic rejection being the most common cause of graft loss (35%). The clinical features of the chronic rejection group (n = 25) were compared with those of the group without failure (n = 218). The variables tested by monovariate analysis were cyclosporine dose at 1 year, donor type, donor and recipient age, and acute rejection episodes. The incidence of graft loss due to chronic rejection was 4% (4/109) in patients who had no acute rejection and 16% (21/134) in those with at least one acute rejection episode (P = 0.002). Donor age (< or = 5 years) was a risk factor for chronic rejection (P = 0.024). Recipient age and donor type were not significantly different between the chronic rejection group and the control group. Using time-dependent covariates, the risk factors were an acute rejection episode (P = 0.003) and low cyclosporine doses at 1 year (P = 0.02). We conclude that acute rejection and low cyclosporine doses in these pediatric patients were risk factors for graft loss due to chronic rejection.

Adolescent↗
PubMed1996

Peritoneal dialysis prescription for neonates.

Despite the major advances in the management of renal failure, the mortality and morbidity rates remain higher in neonates than in older children. But, in most of the cases, effective peritoneal dialysis is possible, giving these neonates a chance of life. In infants and neonates, peritoneal permeability seems to be in a hyperpermeable state, perhaps only related to the volume of the instilled dialysate. Practical peritoneal prescriptions in neonates have to be balanced between either short dwell times optimizing ultrafiltration or long dwell times optimizing the diffusive process and blood purification. The recommendations for peritoneal dialysis in neonates usually admitted are short dwell times, one hour or less, adapted to ultrafiltration need, and small instilled dialysate volumes, 10-20 mL/kg initially, to avoid raised intra-abdominal pressure. Age-related particular risks are hyponatremia and hypophosphatemia.

Female↗
PubMed1996

Determination of individual ultrafiltration time (APEX) and purification phosphate time by peritoneal equilibration test: application to individual peritoneal dialysis modality prescription in children.

Efficiency of peritoneal dialysis (PD) is dependent on adequate ultrafiltration (UF) and purification (solute clearance). These two goals apparently seem to conflict in terms of duration of dwells: short dwell time enhances UF capacity and, conversely, long dwell time enhances solute clearance. Peritoneal equilibration test (PET) allows an approach to the ultrafiltration time: the point at which the over time dialysate urea saturation and glucose desaturation curves cross, call APEX time. PET also allows an approach to the purification time: the point at which dialysate-to-plasma (D/P) concentration ratios over time are high. Because of the value of phosphate as a uremic factor of morbidity, we have chosen the time at which D/P phosphate is equal to 0.6 as a purification phosphate dwell time (PPT). A total of 17 patients were studied, over a five-year period, allowing 142 determinations. APEX times (range 18-71 min) and PPT (range 105-238 min) were spread over a wide distribution. PPT and APEX times were significantly shorter in children younger than three years of age than in children older than ten years of age. PPT were nearly four times longer than APEX times. Knowledge of these conflicting ultrafiltration and purification times should help, in our view, in the individual choice of the PD modality: if UF is the major goal, short dwell times should be used (automated PD); if purification is the major goal, long dwell times should be used, as in continuous ambulatory peritoneal dialysis; if both are the target goal, tidal PD should be discussed.

Adolescent↗
PubMed1996

Use of intraperitoneal pressure, ultrafiltration and purification dwell times for individual peritoneal dialysis prescription in children.

Tolerance of peritoneal dialysis is, in a part, dependent on intraperitoneal dialysate volume. Measurement of intraperitoneal pressure (IPP) in cm of water is easy to perform especially with the twin bag Y set (Baxter). Today we use IPP for following surgical catheter implantation (delaying, starting and progressing with peritoneal dialysis) and for optimizing ultrafiltration and purification. Efficiency of peritoneal dialysis is dependent on adequate ultrafiltration (UF) and on adequate purification (solute clearances). These two goals seem apparently conflicting in terms of duration of dwells: short dwell time enhances UF capacity and conversely long dwell time enhances solute clearance. Peritoneal equilibration test (PET) allows an approach to the ultrafiltration time: the point at which the overtime dialysate urea saturation and glucose desaturation curves cross, called APEX time. PET allows also an approach of the purification time: the point at which dialysate (D) to plasma (P) concentration ratios over time are high. Because the value of phosphate as uremic factor of morbidity, we have chosen the time for D/P phosphate equal to 0.6 as a purification phosphate dwell time (PPT). A total of 17 patients were studied, over a five-year period allowing 142 determinations. APEX times (range 18 to 71 min) and PPT (range 105 to 238 min) were spread over a wide distribution. PPT and APEX times were significantly shorter in children younger than 3 years of age than in children older than 10 years of age. PPT were nearly four times longer than APEX times. The knowledge of these conflicting ultrafiltration and purification times should help, in our view, in the individual choice of the PD modality: if UF is the major goal, short dwell times should be used (automatic PD); if purification is the major goal, long dwell times should be used (CAPD); if both are the target goal, tidal PD should be discussed.

Child↗
PubMed1996

Relationship between intraperitoneal hydrostatic pressure and dialysate volume in children on PD.

As a result of the theoretical risk of an excessive increase in intraperitoneal pressure (IPP) in association with peritoneal dialysis, reduction of instilled intraperitoneal dialysate volume (IPV) is often proposed in infants compared to adults; a further reduction is often noted in neonates compared to children. To better evaluate the significance of this risk, we have tested the relationship between the IPP (cm of water) and the IPV (mL/m2) in our population of children on peritoneal dialysis (n = 17) during the last three years. IPP was measured after a nocturnal dialysis session, during a morning study day, after sequential exchanges of ten minutes' dwell time each, with progressively increased instilled dialysate volumes from 600 to 1400 mL/m2. Mean IPP values were 8.2 +/- 3.8 cm for a mean IPV of 990 +/- 160 mL/m2 body surface area. These values are lower than the IPP values established for adults (13.4 +/- 3.1 cm), which were given for higher IPV values of 1585 +/- 235 mL/m2. The relationship between IPP and IPV was age-dependent. In neonates, stable IPP values (3.5 +/- 1.6 cm) were noted for IPV from 600 to 800 mL/m2; thereafter, increasing IPV led to an increase in IPP. In the range of 600 to 1200 mL/m2 IPV, no significant increment of mean IPP was noted in infants (4.8 +/- 2.6 cm) and in children (9.6 +/- 2.1 cm). However, increasing the dialysate volume over 1000 mL/m2 induced an overincrement of the individual IPP value in most cases, and the rise of IPP was substantial when IPV rose from 1200 to 1400 mL/m2.

Adolescent↗
PubMed1995

Urea, creatinine and phosphate kinetic modeling during dialysis: application to pediatric hemodialysis.

The kinetics of urea, creatinine and phosphate removal during dialysis were investigated in pediatric patients using a two-pool model taking into account fluid shifts and mass transfer between the two compartments. It is found that even urea must be described by a two-pool model since it presents a post dialysis rebound due to equilibration between the two compartments. Phosphate plasma concentration drops very sharply during the first hour of dialysis and rises rapidly during the rebound period. This pattern cannot be accounted for by the classical two-pool model with constant generation rate and mass transfer coefficients, but corresponds to a large time-dependent phosphate influx from the intracellular compartment in which phosphate is generated by biochemical reactions or liberated from the bones. This influx was calculated for four patients representing 8 dialysis sessions and was found to reach a plateau after 90 minutes of dialysis, dropping rapidly during the rebound period.

Adolescent↗
PubMed1995

[Role of peritoneal dialysis for the treatment od terminal renal insufficiency in the child].

Peritoneal dialysis (PD) is the most common used method of treatment for end stage renal failure, specially adapted for home dialysis, easily applicable even for infants. PD creates a degree of independence but also of responsibility. PD failed out with time (transfered to hemodialysis) secondary to familial and medical (peritonitis) exhaustions. Anyway PD has become in children under 15 years old, the more used dialysis modality in many countries (Canada, USA, Australia, England, Italy, Germany, Holland, ...) but remained rarely performed in France (economical, political, social or medical environment reasons). Reduction of waiting time for transplantation should favor the development of PD. Home treatment by PD is without doubt the best dialysis condition in terms of optimal children development but is really a familial charge.

Child↗
PubMed1995

[Ocular involvement in dermatomyositis. Apropos of the case of a 15-year-old girl].

We relate the case of a 15 years old girl who suffered a sudden and severe bilateral lowering of the eyesight, on the occasion of a dermatomyositis. The evolution, over a year, showed a remission of the systematic appearances but there was a limited recovery of the eyesight, the diffuse retinal lesions are the sign of a more extensive vascular problem, found in case of paediatric dermatomyositis.

Adolescent↗
PubMed1995

Nutritional effects of KT/V in children on peritoneal dialysis: are there benefits from larger dialysis doses?

Dialysis adequacy is monitored by urea kinetic modeling (UKM), in particular by calculation of KT/V (normalized whole body urea clearance) and PCRN (normalized protein catabolic rate). All children on peritoneal dialysis from our unit (7 children; mean age 7 years, 8 months) participated in our study (dialysis research program of the French Registry of Peritoneal Dialysis). Every month analysis of dialysate and urine collections and blood samples were compared to a 3-day diet survey to analyze the relations between doses of dialysis (KT/V) and nutrition [dietary protein intake (DPI) and caloric intake]. Calculated protein intake and DPI were also compared. Spearman correlation coefficients were used to assess the association between variables. KT/V values were spread over a wide range (0.8-2.8, mean 1.9). KT/V was positively (weakly) correlated to PCRN (p = 0.07, y = 0.24x + 1.08, r = 0.2), but not to DPI. No correlation could be found between PCRN and DPI, but doses of dialysis (KT/V) were positively correlated to caloric intake (p = 0.001, y = 28.97x + 13.66, r = 0.424). We assume that the correlation between KT/V and PCRN is not necessarily the reason, but only a calculation effect. On the contrary, the positive correlation between KT/V and caloric intake allows us to speculate that more efficient dialysis enhances appetite.

Child↗
PubMed1994

Molecular characterization of human Ig heavy chain DIR genes.

Antibody VDJ recombination is ensured by evolutionarily conserved recombination signals (RS). The 12/23 rule postulates that only gene segments with asymmetrically spaced RS recombine with one another. Two unusually long D genes (170 bp) with irregular RS (DIR) have been reported in humans and have been postulated to participate actively in VDJ recombination, thus frequently contributing to the Ab heavy chain third hypervariable region (CDR3). However, the limited sequence information retained in the CDR3 along with significant sequence diversity has precluded an accurate assessment of the actual role and genomic diversity of DIR genes. Furthermore, DIR genes pose an interesting puzzle in terms of their precise mechanism of recombination because they possess multiple and imperfect RS, often located up to 30 bp away from the recombining fragment within the DIR coding region. Here we present conclusive evidence for the existence of additional human germ-line DIR genes and preliminary evidence that suggests the absence of DIR-like sequences in nonprimate animals. We also show that DIR genes are under the transcriptional control of VH-independent promoters and have the potential to encode a D mu protein of 105 amino acids. Finally, DIR genes seem at least in early fetal life to recombine preferentially through the conventional 3' RS.

Animals↗
PubMed1994

Management of fluid overload in infants by tidal peritoneal dialysis: is there a benefit compared with continuous cycling peritoneal dialysis?

Dialysed infants are sometimes characterized by a hyperpermeable peritoneal state. In this situation decreasing dwell time and/or increasing dialysate tonicity are usually proposed to achieve adequate ultrafiltration (UF). We have investigated UF capacity under different peritoneal dialysis modalities in three infants. UF was not obtained with isotonic continuous ambulatory peritoneal dialysis (CAPD), and was only achieved with short dwell times and hypertonic CAPD. For the prescription of automated peritoneal dialysis, a shorter dwell time of hourly sequences is needed, which consequently decreases the phosphate diffusion time. Continuous cycling peritoneal dialysis with sequences of 1 h allowed efficient UF [UF/glucose absorption (UF/G) 4.2 +/- 0.9] but the dialysate/plasma (D/P) phosphate ratio was low (0.47 +/- 0.12). In contrast, tidal peritoneal dialysis gave a better UF/G ratio (6.8 +/- 0.7) without a decrease in the D/P phosphate ratio (0.64 +/- 0.18).

Body Fluids↗
PubMed1994

Short-term niflumic-acid-induced acute renal failure in children.

Several reports emphasize the adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs) on renal function. We have observed over the last 10 years seven cases of acute renal failure (ARF) due to immune interstitial nephritis in children. A recommended oral or rectal dose of niflumic acid was prescribed for ear-nose-throat disorders. Length of exposure was 1-5 days. Clinical symptoms (oedema, oliguria or anuria) appeared between 3 and 6 days. Three patients had previously received the drug. Hypersensitivity signs (fever, skin rash, eosinophilia, and/or increased IgE) were present in all cases, leukocyturia in five cases, and haematuria in six cases. Renal biopsy showed interstitial lesions with lymphocyte, eosinophil, and plasma cell infiltrates without tubular cell necrosis. Glomeruli were normal on light-microscopy, except in one patient. Electron-microscopy showed extensive podocyte fusion in two patients, who had clinical and laboratory evidence of nephrotic syndrome (NS). ARF rapidly disappeared after NSAID withdrawal, except in two patients whose renal failure was irreversible despite methylprednisolone bolus. ARF is very rare in children treated with niflumic acid. When ARF occurs, different pathophysiological mechanisms are involved but the most common is immunological.

Acute Kidney Injury↗
PubMed1994

[Gitelman syndrome in children: true hypokalemia but false Bartter syndrome].

BACKGROUND: Gitelman's syndrome or familial hypokalemia-hypomagnesemia and Bartter syndrome share some common features but their prognosis is quite different. CASE REPORT: Four unrelated children, aged 5 to 12 years, were studied because they suffered from muscle cramps and/or abdominal pain. Supportive findings included: hypokalemia (2.1 to 2.9 mmol/l), metabolic alkalosis (31 to 34 mmol/l), hyperkaliuresis (5.8 to 7.1 mmol/kg/day), hypomagnesemia (0.58 to 0.64 mmol/l), hypermagnesuria (0.19 to 0.23 mmol/kg/day), hypocalciuria (0.012 to 0.021 mmol/kg/day). Blood pressure contrasting with high renin activity (19.04 to 20.03 ng/ml/hr) was normal. Chloride fractional excretion after oral water supplementation was only slighty decreased and hypercalciuric response to furosemide administration was not observed. Supplementation with magnesium chloride failed to correct hypomagnesemia while potassium chloride improved hypokalemia. CONCLUSIONS: Age of onset, tetany manifestations, absence of growth retardation, hypermagnesuria despite, hypomagnesemia, hypocalciuria not improved by furosemide favor the diagnosis of Gitelman's syndrome rather than that of Bartter syndrome initially considered.

Bartter Syndrome↗
PubMed1994

Hydrostatic intraperitoneal pressure in children on peritoneal dialysis: practical implications. An 18-month clinical experience.

Intraperitoneal pressure (IPP) is easy to measure routinely in children on peritoneal dialysis (PD) (especially with the twin bag Y-set) as described in adults: value expressed in centimeters of water, average of IPP (mean IPP) at inspiration and at expiration, with point zero located on the mid-axillary line while the patient rests in a perfectly supine position. IPP remained high during the first two to three days postsurgical peritoneal catheter implantation (15 +/- 4 cm) despite low dialysate volume per exchange (10 mL/kg). Afterwards, IPP decreased (10 +/- 2 cm) despite increasing dialysate volume from 10-50 mL/kg. Mean IPP seemed lower in infants (5 +/- 3 cm) in contrast to children (10 +/- 2 cm) on chronic PD with dialysate volume of 1000 mL/m2. There was a strong negative linear correlation between ultrafiltration (UF) volume and mean IPP with isotonic dialysate (1.36% dextrose concentration). By contrast, there was only a weak positive linear correlation between UF volume and mean IPP with hypertonic dialysate (3.86% dextrose concentration).

Adolescent↗