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Biomedical subjects

J B Palcoux

Publications and source records attributed to J B Palcoux.

At least 19 recordsLinked to original sources
PubMed2000

[Verotoxin-producing Escherichia coli infections: study of its prevalence in children in the Auvergne region].

Verotoxin producing Escherichia coli (VTEC) have been associated with disease outbreaks of diarrhea hemorrhagic colitis and hemolytic-uremic syndrome in humans. Contamination occurs mainly by ingestion of beef and dairy products, but water and person to person transmission have also been described. Most of the clinical signs are due to the production of Stx1 and/or Stx2 Shiga toxins, also called verotoxins. Other virulence factors include enterohemolysin, and the product of the eae gene, intimin, involved in the attaching and effacing adherence phenotype. The predominant serotype is O157:H7, but VTEC strains of more than one hundred serotypes can cause human disease. In order to determine the prevalence of VTEC infections among children in the central part of France, stool samples from hospitalized children were examined for stx1 and stx2 genes by using a polymerase chain reaction (PCR) technique. From October 1997 to September 1998, 658 stool samples were analysed: among them 19 (3%) were stx-PCR positive. Only 8 children out of 19 had diarrhea, and for 5 of them, an enteric pathogen other than VTEC was isolated. VTEC strains were isolated from 10 samples: most of the isolates did not produce verotoxins at a high level, and they did not belong to serotypes associated with pathogenicity, which might explain the absence of relationship between VTEC isolation and pathogenicity in our study.

Adolescent↗
PubMed2000

Prevalence and characterization of Shiga toxin-producing Escherichia coli isolated from cattle, food, and children during a one-year prospective study in France.

During a 1-year survey of Shiga toxin-producing Escherichia coli (STEC) prevalence in central France, 2,143 samples were investigated by PCR for Shiga toxin-encoding genes. A total of 330 (70%) of 471 fecal samples collected from healthy cattle at the Clermont-Ferrand slaughterhouse, 47 (11%) of 411 beef samples, 60 (10%) of 603 cheese samples, and 19 (3%) of 658 stool specimens from hospitalized children with and without diarrhea were positive for the stx gene(s). A STEC strain was isolated from 34% (162 of 471) of bovine feces, 4% (16 of 411) of beef samples, 1% (5 of 603) of cheese samples, and 1.5% (10 of 658) of stool specimens. Of the 220 STEC strains isolated, 34 (15%) harbored the stx(1) gene, 116 (53%) harbored the stx(2) gene, and 70 (32%) carried both the stx(1) and stx(2) genes. However, 32 (14.5%) were not cytotoxic for Vero cells. The eae gene, found in 12 (5%) of the 220 strains, was significantly associated with the stx(1) gene and with isolates from children. Sequences homologous to ehxA were found in 102 (46%) of the 220 strains. Thirteen serotypes, OX3:H2, O113:H21, O113:H4, OX3:H21, O6:H10, OX178:H19, O171:H2, O46:H38, O172:H21, O22:H16, O91:H10, O91:H21, and O22:H8, accounted for 102 (55%) of 186 typeable isolates, and only one strain (0.5% of the 186 STEC isolates from cattle), belonged to the O157:H7 serotype. We showed that the majority of the STEC isolates from cattle, beef, and cheese were not likely to be pathogenic for humans and that the STEC strains isolated from children in this study were probably not responsible for diarrheal disease. Finally, the strains associated with hemolytic-uremic syndrome in the same geographical area were shown to belong to particular subsets of the STEC population found in the bovine reservoir.

Abattoirs↗
PubMed1999

Large-volume leukapheresis procedure for peripheral blood progenitor cell collection in children weighing 15 kg or less: efficacy and safety evaluation.

BACKGROUND: We update our experience on large-volume leukapheresis (LVL) in very small patients with malignancies. LVLs were performed with the aim of reducing the psychological impact of leukaphereses by reducing the number of procedures while collecting large numbers of cells. PROCEDURE: Seventeen LVLs were performed using a Cobe Spectra separator in 14 patients weighing < or = 15 kg. A median of 3.8 patient's blood volumes corresponding to 296 mL/kg (range, 202-565) of blood was processed per session of 190 minutes (120-279) duration. A femoral catheter was installed specially for collection for 88% LVL (vs. 35% for standard leukaphereses). A median volume of 16.9 mL/kg was collected with 5.4 x 10(8) MNC/kg (range, 0.6-16.3) and 8.2 x 10(6) CD34+ cells/kg (range, 1.3-31.7). RESULTS: No signs of complications due to citrate toxicity were encountered. No hypotensive or hypothermic episodes were observed. Platelet counts were significantly diminished after each procedure (median: -59%). When the extracorporal line was not primed with red blood cells (RBC), the difference between pre-LVL and post-LVL hemoglobin levels was significant with a median 32 g/L decrease. CONCLUSIONS: The LVL approach for peripheral blood progenitor cells (PBPC) collection in very small children may expose them to the risk of anemia and thrombocytopenia and an excess of special central line installation. The application of this technique in these patients should be reserved for special cases when a very large number of cells must be collected and should be performed by an experienced team.

Anemia↗
PubMed1999

[Cardiac involvement during classic hemolytic uremic syndrome].

BACKGROUND: Cardiac involvement rarely occurs in classic hemolytic uremic syndrome (HUS); it is often fatal. CASE REPORTS: The first patient, a 21-month-old boy, developed classic HUS with acute renal failure. Peritoneal dialysis was performed for 20 days. On the 10th day of dialysis, myocardial infarction occurred, probably related to coronary thrombus. The patient was given heparin and antibiotics because of an unexplained fever. The outcome was favorable despite antero-apical cardiac necrosis, and moderated chronic renal failure. The second patient, a 24-month-old girl, also showed a classic HUS, which required peritoneal dialysis for 10 days. Dilated cardiomyopathy with cardiac failure appeared on the 4th day of dialysis, not related to the volume overload and metabolic consequences of the acute renal failure, such as systemic hypertension or ineffective dialysis. On the 5th day of dialysis neurological involvement appeared. Neurological, cardiac and renal outcome was favorable. The third patient, a 25-month-old girl, developed a classical HUS, requiring peritoneal dialysis for 25 days. No cardiac insult appeared during the acute phase of the disease. After dialysis, the child had chronic renal failure (creatinine clearance: 15 mL/min/1.73 m2). Dilated cardiomyopathy appeared 3 months later, without definite etiology. The outcome was favorable with digoxin treatment. CONCLUSION: A cardiac involvement should also be searched for in the acute phase of HUS and several months later.

Acute Kidney Injury↗
PubMed1998

Determination of the genomic structure of the COL4A4 gene and of novel mutations causing autosomal recessive Alport syndrome.

Autosomal recessive Alport syndrome is a progressive hematuric glomerulonephritis characterized by glomerular basement membrane abnormalities and associated with mutations in either the COL4A3 or the COL4A4 gene, which encode the alpha3 and alpha4 type IV collagen chains, respectively. To date, mutation screening in the two genes has been hampered by the lack of genomic structure information. We report here the complete characterization of the 48 exons of the COL4A4 gene, a comprehensive gene screen, and the subsequent detection of 10 novel mutations in eight patients diagnosed with autosomal recessive Alport syndrome. Furthermore, we identified a glycine to alanine substitution in the collagenous domain that is apparently silent in the heterozygous carriers, in 11.5% of all control individuals, and in one control individual homozygous for this glycine substitution. There has been no previous finding of a glycine substitution that is not associated with any obvious phenotype in homozygous individuals.

Alanine↗
PubMed1997

Plasma exchange in Rasmussen's encephalitis.

The authors observed a 4-year-old girl who has Rasmussen's encephalitis. She started with frequent localized and generalized seizures. Standard antiepileptic treatment was almost ineffective. The frequency of the generalized seizures decreased, but the myoclonic jerks of the left part of the body persisted. An EEG showed partial status epilepticus. The results of the CT scan were normal. Antibodies to viruses were absent from the blood and cerebrospinal fluid. An MR scan showed a T2-weighted hypersignal zone in the right frontal region. Intravenous bolus injections of corticosteroids and drips of immunoglobulins were inefficient, and we started plasma exchanges which have continued for 9 months. The clinical state stabilized, and the images on the MR scan improved, but the results of the EEG did not improve. The authors discuss the effect of the plasma exchange, the use of which is questionable in this disease.

Brain↗
PubMed1993

Treatment of homozygous familial hypercholesterolemia by plasma exchange and LDL-apheresis.

Two girls with familial hypercholesterolemia were treated for 7 years by plasma exchanges (PE) or LDL-apheresis (LA). We compared different methods of treatment; PE with or without reuse of the plasma separator, LA of varying frequency, and LA with or without oral administration of simvastatin. We assessed the long-term results by measuring the blood levels of the biochemical parameters before sessions, and determined the effectiveness of each session by the percentage of decrease in the blood levels between the beginning and the end of the sessions. LA led to a more selective treatment (lowering of LDL cholesterol and maintenance of HDL cholesterol), but the blood levels of total cholesterol before sessions were the same as those obtained by PE. IgG and haemoglobin levels decreased little with LA. The rhythm of one session a week gave better results in LA. Although reuse of the plasma separator represents a financial saving it produced poorer results. The oral administration of simvastatin improved the results of LA.

Adolescent↗
PubMed1992

Complement activation during low-density lipoprotein apheresis.

Complement system activation was investigated in two girls with familial homozygous hypercholesterolemia undergoing two monthly sessions on LA15 or LA40 (Kaneka liposorber). We determined blood levels of C3c and C3a, leukocyte counts, and plasma levels of C3c and C3a in the extracorporeal circulation device at the start of the sessions and 15 and either 60 or 120 min into them. Sequential eluates were collected from LA40 at the end of the sessions (0.5M NaCl, 1M hydroxylamine). Anaphylatoxin C3a increased throughout, especially with LA40. As previously reported, C3a was trapped in the dextran column but was noticeably present in efferent plasma. Besides many proteins, nonnative complement fragments bearing C3a and C3d antigens were detected in almost all the eluates, suggesting possible in situ complement activation. Practically, complement activation induced by the first filter is a risk; long-term side effects may arise from this extracorporeal circulation device.

Blood Component Removal↗
PubMed1992

[Evaluation of a three-year (1988-1990) prenatal screening of malformative uropathies in the department of Puy-de-Dôme].

During a 3-year period, 93 prenatal diagnoses of kidney or urinary tract abnormalities were carried out in the French district of Puy-de-Dôme. Sixty-nine mothers were resident in this area giving an incidence of 2.8 out of 1000 births. The pregnancy was interrupted in 10 cases, there were 2 stillbirths and three infants died within two months of life. The most frequent abnormalities were: hydronephrosis (48% of cases), megaureter with or without ureter duplication (19%) and multicystic dysplasia (16%). The prenatal diagnosis was confirmed after birth in 82% of cases. Of the 56 infants with obstructive uropathies, 17 underwent a pyeloplasty within three months of life, 32 had conservative treatment, of whom 4 were operated on afterwards, and seven could not be traced. Of the seven infants who had normal ultrasound scan at birth, three had abnormal scan during the follow-up one of whom was operated on. Nephrectomy was not performed in any of the 11 cases of multicystic dysplasia: one patient was lost to follow up, three had stable lesions and in seven cases, the size of the cysts decreased.

Female↗
PubMed1989

[Diagnosis of deficiency in cofactor of phenylalanine hydroxylase: a metabolic emergency].

We report on two cases of children suffering from biopterin synthetase deficiency. Both were treated with the same treatment schedule with biopterin and neurotransmitters: 6-hydroxytryptophan and dihydrophenylalanine (DOPA). The only difference between the two cases is the time of diagnosis and therefore of treatment. The child who was treated early has a normal neurologic development. The other one has been treated since he was 7 months old and is mentally deficient (DQ = 0.60). This older child also suffers from dystonia probably secondary to Levodopa treatment. The authors emphasize the uncertainty of these patient's evolution owing to complications of the disease itself or those due to prolonged treatment by neurotransmitters.

5-Hydroxytryptophan↗
PubMed1989

[Outcome of the kidney with vesico-ureteral reflux. Apropos of 129 cases].

The final status of the kidneys of 129 children suffering from vesico-ureteric reflux was studied. The growth of the kidneys was comparable in the surgically treated and in the medically treated group. However, growth was better when the kidneys had been normal initially than when they presented renal scars. New scars were more frequent in the medically treated group, and/or when scars were already present at diagnosis of vesico-ureteric reflux. Our results are in agreement with those in the literature.

Adolescent↗
PubMed1988

Acute pancreatitis in six non-transplanted uraemic children. A co-operative study from the French Society of Paediatric Nephrology.

Ten clinical episodes of acute pancreatitis (AP) occurred in six patients (mean age 10 years, range 3-15 years) with chronic renal failure (CRF) during a 9-year period (1977-1986). The underlying cause of CRF was vesicoureteral reflux (2); urethral valves (1); ureterohydronephrosis (1); nephronopthisis (1) and a haemolytic uraemic syndrome which occurred 12 years before (1). In all patients a diagnosis of AP was established both on clinical grounds and with a serum amylase level of greater than 600 IU/l. In 3 patients laparotomy was performed because of suspected appendicitis. All patients required exclusive parenteral feeding (mean duration 25 days) and 2 patients had a partial pancreatectomy. No patient developed pancreatic pseudocysts, 2 patients experienced one relapse (3 and 21 months later) and 1 patient had two relapses and died. Mean duration of follow up was 3 years (range 1-10 years). Possible aetiological factors were: choledochal cyst (1); parotitis without a rise in mumps antibodies (1); familial dyslipidaemia but without AP in other family members (1), and aluminium intoxication with hypercalcaemia and convulsive encephalopathy treated with valproic acid in 1 patient. Severe hyperparathyroidism with radiological signs was absent in all patients. Transplantation had been performed either before AP in 2 patients (1 and 3 years before AP) or had followed AP in 1 patient (7 years after) without occurrence or relapse of AP.

Acute Disease↗
PubMed1988

[Changes of erythrocyte and lymphocyte membrane fluidity after plasma extraction in children with type II homozygous hypercholesterolemia].

Two young girls with type IIa homozygotic familial hypercholesterolemia were treated by plasma exchange to reduce circulating cholesterol levels, values prior to treatment being abnormally elevated (greater than 10 mmol/l). Simultaneous determination of membrane fluidity (by fluorescence polarization) of erythrocytes and lymphocytes showed marked decreases due principally to an increase in the intramembrane cholesterol/phospholipid ratio. Values after treatment showed a tendency to return to physiologic levels without, however, attaining normal values. In vitro studies of cholesterol incorporation in these membranes demonstrated the primordial role of cholesterol in these processes of membrane rigidity, and their reversibility. It is suggested that certain physical membranal properties could provide a useful index to assess need for more or less frequent plasma exchanges.

Child↗