pBFK, a new thermosensitive shuttle vector for Streptococcus pyogenes gene deletion by homologous recombination.

Streptococcus pyogenes, or Group A Streptococcus (GAS), is a major human pathogen for which genetic manipulation remains an ongoing challenge. We created a new temperature-sensitive plasmid pBFK expressing spectinomycin resistance adapted to homologous recombination procedure to perform a complete gene deletion in GAS. Herein the mutagenesis strategy with pBFK was performed in a highly virulent GAS emm3 genotype.

Neuromyelitis optica spectrum disorders in South of Tunisia: A rare entity with low seroprevalence of anti-aquaporin 4 autoantibodies.

INTRODUCTION: Screening for anti-aquaporin 4 (anti-AQP4) antibodies, a specific marker of neuromyelitis optica spectrum disorders (NMOSD), is part of the immunological investigation performed in a context of central nervous system (CNS) inflammation with optic neuritis and/or myelitis. The aim of our study was to evaluate the prevalence and the diagnostic value of anti-AQP4 antibodies in Tunisian patients with such inflammatory neurological conditions. METHODS: During 3years, 170 consecutive serum samples of Tunisian patients with CNS inflammatory disorders and optico-spinal involvement were tested in our laboratory for anti-AQP4 antibodies using indirect immunofluorescence on transfected cells. RESULTS: The global seroprevalence of anti-AQP4 in our study was 4.1% (7 cases/170). The diagnosis of NMOSD was made for the 7 seropositive patients and for 2 seronegative patients, which leads to a seroprevalence of 77.7% in our NMOSD subgroup. The detection of anti-AQP4 allowed the diagnosis of NMOSD in 4 patients with incomplete clinical presentation and 5 patients with positive antinuclear antibodies. In one case, seropositivity was detected in a second sample, one year after an initial seronegativity. CONCLUSION: NMOSD seem to represent a rare etiology of optic neuritis and/or myelitis in Tunisian patients. Despite its low global seroprevalence in our study population, anti-AQP4 appears to be a very clinically relevant marker for NMOSD diagnosis. Repeating the screening in case of initial negativity could be interesting in clinical practice.

[Pediatric Crohn's disease in Tunisia]. / La maladie de Crohn de l'enfant en Tunisie.

UNLABELLED: Crohn's disease occur mainly in adults. However, pediatric onset forms are not rare and have many characteristics. AIM: to study clinical, diagnostic, therapeutic and evolutive characteristics of crohn's disease in tunisian children. METHODS: Retrospective multicenter study conducted in 10 pediatric departments on a period of 10 years (2000-2008) RESULTS : 43 children were included. The sex-ratio was 1.68. The mean age at the onset of the symptoms was 11+/-2.3 years (5-16 years). The age of onset was inferior to 10 years in 25 % of the children. The delay before management was superior to 1 year in 25% of cases. The initial symptoms were dominated by diarrhea (95%). Perineal manifestations were present at diagnosis in 30% of children and extra-digestive manifestations in 53%. Ileocolonic localization was the most frequent (46%). The initial disease flare was moderate in 83% of cases. The treatment was medical in 77 % of cases, nutritional and medical in 18.5%. Maintenance therapy was instituted in 86% of cases and consisted essentially in azathioprin (62%). The mean follow-up was 3 years and 4 months. 60% of the children had at least one acute flare. During evolution, 7% of children had anoperineal surgery and 11% an intestinal resection. CONCLUSION: Crohn's disease seems rare in Tunisia. The time of diagnosis is often delayed. The management is based on immunosuppressive therapy and nutritional support.

Gastric atrophy and Helicobacter pylori infection in children.

AIM: To assess the prevalence of gastric atrophy (GA) in Tunisia (a high prevalence region for Helicobacter pylori), and describe its histological, clinical and endoscopic features in children. METHODS: 345 children, 151 male and 194 female, mean age 8.6 +/- 3.7 years, underwent upper gastrointestinal (UGI) endoscopy with gastric biopsies for recurrent abdominal pain (n=232, 67.2%), vomiting (n=72, 20%) associated with or without upper gastrointestinal bleeding (n=59, 17.1%) and miscellaneous causes (n=53, 15.4 %). Biopsies performed both in the gastric antrum (n=2) and corpus (n=2) were analysed for histological assessment according to the updated Sydney classification system and bacterial culture. A positive result was recorded where histology and/or culture were positive, confirming the presence of H. pylori infection (H. pylori +ve). A negative result was recorded when both tests were concomitantly negative (H. pylori -ve). RESULTS: 9.3% (32/345) of the total population, and 14.5% (32/221) of chronic gastritis patients exhibited GA, M/F: 16/16, mean age (SD) 9.4 (3.4) years. Amongst the 32 children with GA, 30 (93.7%) were H. pylori +ve and 2 (6.3%) were H. pylori -ve. GA was localised in the antrum (n=26, 81.2%), the fundus (n=2, 6.3%) and was also seen in both (n=4, 12.5%). GA was categorised as mild, grade 1 (n=18, 56.3%); moderate, grade 2 (n=13, 46.6%); and severe, grade 3 (n=1, 3.1%). GA was associated with mild active gastritis in 18 cases (56.3%). The prevalence of moderate or severe antral GA was detected in 9/26 (34.6%) of H. pylori +ve vs. any of H. pylori -ve (p=0.4), whereas GA in the corpus was detected in 1/2 (50%) vs. none, respectively. None exhibited intestinal metaplasia. There were no clinical features specific to this pathology. UGI endoscopy in GA patients showed nodular gastritis (n=17, 53.1%), congestive gastritis (n=9, 28.1%), and normal tissue (n=6, 18.8%). GA was significantly associated with H. pylori infection (p<0.0001) and nodular gastritis (p<0.005). CONCLUSION: GA was found in 9.3% of Tunisian children undergoing UGI endoscopy and was significantly associated with H. pylori infection and nodular gastritis.

Foetus-in-fetu: an unusual cause of abdominal mass in the newborn.

Foetus-in-fetu (FIF) is a rare congenital condition in which a vertebrate foetus is incorporated within its twin. The authors report the case of a newborn girl with prenatal ultrasonographic diagnosis of an intra-abdominal mass. Abdominal ultrasonography and computed tomography of the abdomen showed a heterogeneous cystic mass containing multiple calcifications. The patient had a laparotomy at 18 days of age with excision of a well-encapsulated 6 x 5 cm retroperitoneal mass, containing many organs. Anatomicopathologic examination showed a relatively well-differentiated FIF attached to an amniotic sac by a rudimentary umbilical cord. Encephalon, coroidal plexus, vertebral bodies, rudimentary limbs, thyroid gland and teeth were identified. The postoperative period was uneventful.

Study of hypothalamic leptin receptor expression in low-birth-weight piglets and effects of leptin supplementation on neonatal growth and development.

Low birth weight resulting from intrauterine growth retardation (IUGR) is a risk factor for further development of metabolic diseases. The pig appears to reproduce nearly all of the phenotypic pathological consequences of human IUGR and is likely to be more relevant than rodents in studies of neonatal development. In the present work, we characterized the model of low-birth-weight piglets with particular attention to the hypothalamic leptin-sensitive system, and we tested whether postnatal leptin supplementation can reverse the precocious signs of adverse metabolic programming. Our results demonstrated that 1) IUGR piglets present altered postnatal growth and increased adiposity; 2) IUGR piglets exhibit abnormal hypothalamic distribution of leptin receptors that may be linked to further disturbance in food-intake behavior; and 3) postnatal leptin administration can partially reverse the IUGR phenotype by correcting growth rate, body composition, and development of several organs involved in metabolic regulation. We conclude that IUGR may be characterized by altered leptin receptor distribution within the hypothalamic structures involved in metabolic regulation and that leptin supplementation can partially reverse the IUGR phenotype. These results open interesting therapeutic perspectives in physiopathology for the correction of defects observed in IUGR.

[Severe corrosive oesophagitis : are high doses of methyl prednisolone efficient to prevent oesophageal caustic stricture in children?]. / Les oesophagites caustiques severes. Les doses elevees de solumedrol sont-elles efficaces pour prevenir les stenoses caustiques ?

BACKGROUND: Corrosive oesophagitis stricture is the long term complication of severe corrosive oesophagitis. The aim of our study was to evaluate the effect of a high doses of steroids on incidence and quality of oesophageal stricture. PATIENTS AND METHODS: We reviewed the case histories of 28 children seen at children hospital from 31 December 1991 to 31 december 2001. These children has second and third degree oesophageal burns and they were treated by systemic Methylprednisolone (1000mg/1,73/m2 SC). RESULTS: the frequency of stricture was 12/26 (46%). Ten children required A mean of 6,7 (5,74) dilatation range (1 - 17). One patient required an oesocoloplasty. The frequency of stricture in the group treated early before the 24th hour and after the 24th hours was (9/21) (47,4%) versus (3/7) (42,9%). This difference was not significant (P = 1). The frequency of stricture in the group treated less than 21 days and more than 21 days was 6/17 (40%) versus 6/9 (66,7%). This difference was not significant (P = 0,400). High doses of methyl prednisolone seems to decrease the risk of oesophageal stricture. We found no difference between the children treated before the 24th hours and those treated after the 24 hours and those treated less than 21 days and those more than 21 days.

Genetic and mutational heterogeneity of autosomal recessive chronic granulomatous disease in Tunisia.

NADPH oxidase, a multi-subunit protein consisting of cytosolic components and the membrane-bound heterodimer, plays an instrumental role in host defence mechanisms of phagocytes. Genetic deficiency of the enzymatic complex results in an inherited disorder, chronic granulomatous disease (CGD), which is characterized by an impaired phagocyte microbicidal activity. X-Linked (XL) CGD results from a mutation in the CYBB gene encoding the gp91phox subunit, while autosomal recessive (AR) CGD is associated with mutations in one of the NCF1, NCF2 and CYBA genes that encode the p47phox, p67phox and p22phox subunits, respectively. In the study reported here, we investigated genetic defects underlying CGD in 15 Tunisian patients from 14 unrelated families. Haplotype analyses and homozygosity mapping with microsatellite markers around known CGD genes assigned the genetic defect to NCF1 in four patients, to NCF2 in four patients and to CYBA in two patients. However, one family with two CGD patients seemed not to link the genetic defect to any known AR-CGD genes. Mutation screening identified two novel mutations in NCF2 and CYBA in addition to the recurrent mutation, DeltaGT, in NCF1 and a splice site mutation previously reported in a North African patient. Our results revealed the genetic and mutational heterogeneity of the AR recessive form of CGD in Tunisia.

Abdominal tuberculosis in children. Report of 10 cases.

BACKGROUND: Abdominal tuberculosis is a rare location of this infection with a lot of diagnostic difficulties. The aim of this study was to review our experience of pediatric abdominal tuberculosis with that of the literature data. PATIENTS AND METHODS: A retrospective study was conducted over a 7-year period; 10 cases of abdominal tuberculosis in children were reviewed (6 girls and 4 boys, mean age: 11 years, extremes 4-14). Eight patients enrolled in this study satisfied the following criteria: a positive culture for mycobacterium tuberculosis on samples of ascites fluid, sputum, urine, abscess puncture and/or caseating granulomas on histologic examination of biopsies obtained by endoscopy, percutaneous aspiration or needle biopsy or exploratory laparotomy. Two other patients (patients No 1 & 5) had a favorable response within 10 weeks of antituberculous therapy. RESULTS: We observed 8 cases of peritoneal tuberculosis and 2 cases of intestinal tuberculosis. Extra-abdominal tuberculosis was found in 4 of those patients. Two patients had a contact with a tuberculosis positive individual. Nine children had BCG immunization. The main clinical features were abdominal distension (6 cases) and abdominal pain (6 cases). Abdominal ultrasonography visualized mesenteric lymphadenopathies (6 cases), an abdominal mass (5 cases), free (1 case) and localized ascites (1 case). Barium enema and small bowell series showed small bowel stenosis (1 case) and ileal ulcerations (1 case). Exploratory laparotomy, performed in 3 patients, showed whitish granulations and peritoneal abscesses with caseous necrosis on histology. Quadruple therapy with tuberculostatic agents was prescribed in all patients, associating isoniazid, rifampicin, pyrazinamide combined at the start of the treatment with streptomycin (7 cases) and ethambutol (3 cases). Short term outcome was favorable with no deaths. The long term outcome was complicated by persistent ascites (1 case) and the development of portal hypertension (1 case). CONCLUSION: Abdominal tuberculosis remains a rare localization with a lot of diagnostic difficulties.

[High doses of steroids in the management of caustic esophageal burns in children]. / Corticothérapie à forte dose dans le traitement des oesophagites caustiques sévères chez l'enfant.

UNLABELLED: Esophageal burns are frequent in some countries. Esophageal stricture is a severe complication after caustic ingestion. Its frequency is estimated to 5% and reaches 47% in severe esophagitis. AIM OF THE STUDY: To study the influence of management of severe esophageal burns with high doses of steroids in the occurrence of esophageal stricture through the experience of an endoscopic unit. PATIENTS AND METHODS: Twenty-six children with a mean age of 3.5 years (15 months-8 years) with a second b- (N =22) or a third-degree (N =4) esophageal burns due to accidental ingestion of a caustic substance were included between 1993 and 1999. Corrosive substances ingested were sodium hydroxide (N =17), bleach (N =4), alkali (N =3), others (N =2). Upper GI endoscopy was performed in 17 children within the 24 hours of caustic ingestion and within the first 48 hours in all cases. All patients received methylprednisolone (1 g/1.73 m2/day) plus cimetidine and ampicillin plus early oral feeding resumption. RESULTS: Three children (2 grade II et one grade I) were not controlled on day 30 of the protocol and have then been excluded. The remaining 23 children were divided in two groups depending on the upper GI endoscopic results: group I of 12 patients completely or partially healed and group II of 11 patients who developed an esophageal stricture. No difference was observed between the two groups with regard to the delay between caustic ingestion and the start of treatment and the number of shots of methylprednisolone. Second b- degree esophagitis complicated with an esophageal stricture underwent a median of five esophageal dilations (1-12). After a median follow-up of three years, four of them have a normal esophagus. All children with a third-degree esophagitis developed an esophageal stricture. One had a surgical replacement of the esophagus with a segment of colon with good outcome. The three others underwent a median of seven esophageal dilations (5-10). One of them has a normal esophagus after a follow-up of five years while the two others were lost to follow-up. CONCLUSION: High dose of corticosteroids seems to improve second b-degree esophagitis prognosis and may prevent from esophageal stricture.

Visceral leshmaniasis diagnosed on duodenal biopsy in a child.

Visceral leishmaniasis is usually easy to recognize when clinical presentation is complete: splenomegaly, fever and palor associated to pancytopenia, hypoalbuminaemia and hypergamma globulinemia. Bone marrow smears, culture and serology confirm the diagnosis. We report the case of an infant in whom clinical and biological findings are suggestive of leishmaniasis and the diagnosis confirmed only by duodenal biopsy.

[Heterotopic gray matter. Report of four pediatric cases]. / Hétérotopies de la substance grise. A propos de quatre observations pédiatriques.

Severe infant epilepsy is included within difficult etiologic diagnosis. Gray matter heterotopias are an uncommon cause. The authors report four observations of gray matter heteropias concerning three-, six-, seven- and nine-year-old girls, presenting no particular antecedents. No consanguinity was noted. The first occurrence of epilepsy ranged from the age of nine months to the age of four years. A mild mental retardation was found in three cases, and mental regression in one case. A status epilepticus was noted in three children. Magnetic resonance imaging scans showed subependymal heterotopias in one case and diffuse cortical heterotopias in three cases associated to a partial agenesis of corpus calloseum in one case and pachygyria in two cases.

[Chronic septic granulomatosis in a young girl manifesting as invasive pulmonary aspergillosis and flaccid paraplegia]. / Granulomatose septique chronique chez une fillette revelee par une aspergilose pulmonaire invasive et une paraplegie flasque.

UNLABELLED: The invasive Pulmonary Aspergillosis (IPA) is the principal cause of death in patients with chronic granulomatosis disease (CGD). It can happen before age of one and can reveal the (CGD). Usually, the transmission of GSD is linked to x in 65% of cases. We report, the case of a girl aged 3 years issued from consanguine marriage referred to hospital for hemoptysia. We note that at 40 days she presents an suppurate adenitis. She is hypotrophic at--3DS without respiratory problem, she have a splenomegaly. The radiography chest note an alveolar and interstitial opacity bilateral, apical right and basal left. There is a biological inflammatory syndrome. During the evolution, the child presents a paraplegia secondary to compression myelitis. A D5 laminectomy in urgency was done. The vertebral Biopsia, the serology and the culture isolate fumigatus aspergillus the GCD is evoqued confirmed by the NBT test who was negative. IN CONCLUSION: --We have to look for GCD in front of pulmonary aspergillus.--The vertebra lesion is secondary to pulmonary lesion.--Our observation is noticeable by the recessive autosomal transmission who was seen in 35% of cases, and by the neurologic complication rarely reported.