c-ANCA-associated vasculitis with predominant CNS demyelination after COVID-19.

COVID-19 infection may trigger the presentation or exacerbation of autoimmune diseases. c-Antineutrophil cytoplasmic antibody (c-ANCA)-associated vasculitis after COVID-19 mainly involves the kidneys and lungs, and is rarely reported. We describe the case of a 13-year-old girl with a history of chronic immunologic thrombocytopenic purpura who presented with transverse myelitis and central nervous system demyelination, and was subsequently diagnosed with c-ANCA-associated vasculitis following COVID-19. The patient's condition improved after pulse therapy with methylprednisolone and rituximab. To our knowledge, this is the first reported pediatric case of ANCA-associated vasculitis with predominant central nervous system involvement after COVID-19 infection.

First molecular detection of Aichi virus in sewage and shellfish samples in the Monastir region of Tunisia.

The aims of our investigations were (1) to look for Aichi virus in environmental samples and (2) to compare the Aichi virus strains in both clinical and environmental samples in order to evaluate the role of environmental contamination as a possible vehicle for viral transmission. Aichi virus was detected in 15 (6%) sewage samples and in 4 (6.6%) shellfish samples. Aichi virus was identified for the first time in water samples. Phylogenetic analysis revealed several clusters that occurred sequentially in time, suggesting some parallelism in the evolution of environmental and human strains. Aichi virus present in sewage reflects the viruses circulating in the community.

Detection and molecular characterization of enteric viruses in environmental samples in Monastir, Tunisia between January 2003 and April 2007.

AIMS: A prospective study was performed to characterize the main human enteric viruses able to persist in sewage samples and in shellfish tissues, and to establish the correlation between environmental strains and viral infantile diarrhoea observed in the same area during the same period. METHODS AND RESULTS: A total of 250 sewage (raw and treated) and 60 shellfish samples were collected between January 2003 and April 2007 in Monastir region, Tunisia. Group A rotavirus (RVA) was detected in 80 (32%) sewage samples, norovirus (NoV) in 11 (4·4%) and enteric adenovirus (AdV) in 1 (0·4%). Among 60 shellfish samples collected near sewage effluents, one was contaminated by NoV (1·6%). CONCLUSION: Our data represent the first documentation in Tunisia, combining gastroenteritis viruses circulating in the environment and in clinical isolates. We observed a correlation between environmental strains and those found in children suffering from gastroenteritis during the same period study. This suggests the existence of a relationship between water contamination and paediatric diarrhoea. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results address the potential health risks associated with transmission of human enteric viruses through water-related environmental routes. The research findings will aid in elucidating the molecular epidemiology and circulation of enteric viruses in Tunisia and in Africa, where data are rare.

[Childhood pharyngitis in Sfax (Tunisia): epidemiology and utility of a rapid streptococcal test]. / Les angines aiguës de l'enfant dans la région de Sfax (Tunisie) : épidémiologie et intérêt du test de diagnostic rapide.

OBJECTIVE: The authors studied the epidemiology of pharyngitis in children and evaluated the contribution of a rapid streptococcal test. PATIENTS AND METHODS: This prospective study was conducted from June 2007 to May 2008 in a primary health care institution (Policlinique de la Caisse Nationale de Sécurité Sociale) in Tunisia. Clinical findings were recorded; throat swabs were performed, and a rapid streptococcal test was made. RESULTS: Five hundred and four children were included in this study. The mean age was 5 years and 8 months. Culture was positive for group A streptococcus in 166 cases (32.9 %). Group A streptococcus was more frequently isolated in children aged 5 to 8 years. There was no difference in clinical features between groups of streptococcal and non-streptococcal pharyngitis. The sensitivity and specificity of the rapid test were respectively 93.2 and 95.3 %. CONCLUSION: Pharyngitis was of bacterial origin in one third of cases; among these, group A streptococcus was the most frequent bacterium. The rapid test is a quick and reliable tool for the diagnosis of pharyngitis and hence an appropriate treatment.

Use of Tomato leaf curl virus (TYLCV) truncated Rep gene sequence to engineer TYLCV resistance in tomato plants.

Tomato yellow leaf curl disease causes severe losses in tomato production throughout Mediterranean countries including Tunisia. In order to generate engineered resistance to this disease, an intron-hairpin RNA construct harboring a Tomato yellow leaf curl Sardinia virus (TYLCSV) truncated replication-associated protein (Rep) gene was used to transform genotype of tomato plants. Prepared transgenic plants were agro-inoculated with Tunisian infectious strain of TYLCSV and screened for the resistance to infection. The infected transgenic plants were divided into 3 different groups according to their specific symptoms. Only one of them contained transgenic plants fully resistant to the tomato yellow leaf curl disease.

Self-healing Langerhans cell histiocytosis (Hashimoto-Pritzker disease): two Tunisian cases.

Self-healing Langerhans cell histiocytosis (SHLCH) is a rare self-limited variant of Langerhans cell histiocytosis that presents at birth or during the neonatal period. It was first described by Hashimoto and Pritzker in 1973. Subsequently, more than 70 cases have been reported in the literature. Regarding age of onset, SHLCH should be divided into congenital SHLCH and rare late-onset type. We report here two additional cases of SHLCH in Tunisian infants. We emphasize the need for long-term follow-up in such patients.

Evaluation of two gene-silencing constructs for resistance to tomato yellow leaf curl viruses in Nicotiana benthamiana plants.

Infiltration of Agrobacterium tumefaciens into intact plant leaves of N. benthamiana was used to test the efficiency of two virus-based silencing constructs conferring resistance to the closely related begomoviruses. The constructs contained the most conserved sequences of the coat protein (CP) gene and replication-associated protein (Rep) gene of Tomato yellow leaf curl Sardinia virus (Sicily strain) (TYLCSV-[Sic]). Both constructs formed a hairpin structure that enhanced the post-transcriptional gene-silencing mechanism. When agro-infiltrated plants were challenged separately with infectious viruses TYLCSV-[Sic] and Tomato yellow leaf curl virus (TYLCV), the plants showed resistance to TYLCSV-[Sic], but not to the related TYLCV.

Co-occurrence pulmonary haemosiderosis with coeliac disease in child.

Idiopathic pulmonary haemosiderosis (IPH) is a rare and serious disorder in children of unknown aetiolopathogeny. Association of IPH and coeliac disease (CD) is even rarer. Immunological origin of IPH is now well accepted. We report the case of an 11-year-old female admitted for evaluation of recurrent streaky haemoptysis that had been evolving over the previous 9 months. Physical examination revealed weight loss with normal weight, but there was cutaneous and mucosal pallor due to severe anaemia (haemoglobin 4.6g/dl). The chest X-rays showed unilateral alveolo-intertitial infiltrate. Broncho-alveolar lavage revealed 70% haemosiderin-laden macrophages. The diagnosis of IPH was made. Since severe anaemia is disproportionate to radiologic findings, searching associated CD was performed and then confirmed by biological and histological examinations. A gluten-free diet was initiated. Evolution was favourable. Looking for especially CD in IPH should be systematic, even in the absence of gastrointestinal symptoms.

Development of a real-time PCR for Tomato yellow leaf curl Sardinia virus.

Recently, tomato yellow leaf curl disease has become important for the tomato grown both in greenhouse and field conditions in Tunisia. Here, we describe a rapid, specific, reliable, and sensitive real-time PCR, based on TaqMan chemistry, for Tomato yellow leaf curl Sardinia virus (TYLCSV). This method proved suitable for the detection and quantification of this virus in tomato, pepper and bean plants. It detected the virus even in the samples that were negative by conventional assays.

[Eosinophilic granuloma revealed by torticollis: a case report]. / Granulome éosinophile révélé par un torticolis: à propos d'une observation.

UNLABELLED: Langerhans cell histiocytose is a rare condition in childhood. It presents in different ways ranging from a single bony disease to a multisystemic disease involving vital organs. CASE REPORT: We report a case of single bone involvement revealed by torticollis in an eight-year-old boy. The diagnosis was evocated on radiological findings and confirmed by histologic aspects. After a period of 2,5 years, this child is in total spontaneous remission. CONCLUSION: Torticollis must be explored and watched. Eosinophilic granuloma can be a rare aetiology in children. The outcome is often favorable.

[Hypernatremic dehydration in children: retrospective study of 105 cases]. / La déshydratation hypernatrémique chez l'enfant : étude rétrospective de 105 cas.

UNLABELLED: The hypernatremic dehydration defined by a serum sodium concentration> or = to 150 mmol/l, is a particular form of acute dehydration and constitutes a medical emergency requiring a prompt and adequate diagnosis and management. PURPOSE: To precise the epidemiological profile, course, causes and therapeutic particularities of hypernatremic dehydration in children. POPULATION AND METHODS: Retrospective review of 105 children admitted in the general Paediatrics department of the Fattouma Bourguiba university hospital in Monastir (Tunisia), for hypernatremic dehydration between January 1st 1990 and December 31 2002. RESULTS: Hypernatremic dehydration represented 11.51% of all kinds of dehydration. The mean age was 6.5 months with a small male predominance. The socio-economic level of the parents was good in 62.8% of cases. Half of the children were in shock. Severe dehydration was present in 87.6% of cases and neurological signs were observed in 77.14% of cases. The initial mean serum sodium concentration was 159 mmol/L. Acidosis and acute renal failure were associated respectively in 97.2% and 76.2% of cases. Prominent cause of hypernatremic dehydration was diarrhoea (94.3%). Intravenous rehydration with 5% glucose solution at the average of 147 ml/kg/day and containing a mean sodium level of 42 mmol/L was performed in 74% of cases. In most cases (84.1%) serum sodium was normalized within the first 72 hours. Complications were noted in 5.7% of cases and mortality rate was 11.4%. CONCLUSION: Hypernatremic dehydration was common in infant and the prominent cause is still dominated by diarrhoea in our country. The management of hypernatremic dehydration is based on oral or intravenous rehydration and plasma expanding fluids when shock is present or imminent. The serum sodium concentration should be gradually corrected and should not exceed 0.5 mmol/L/h. Prevention is based on the pursuit of breastfeeding and the use of oral rehydration solution in infantile diarrhoeas.

[Neuromeningeal enterovirus infections in Tunisia: epidemiology, clinical presentation, and outcome of 26 pediatric cases]. / Entéroviroses neuroméningées en Tunisie: profil épidémiologique, clinique et évolutif. A propos de 26 cas pédiatriques.

UNLABELLED: Non-polio enteroviruses are the most common identified cause of viral neuromeningeal infections following the introduction of the mumps and polio vaccines. OBJECTIVE: The aim of this study was to describe the epidemiology, clinical presentation, and the outcome of enteroviral infections of the CNS. METHOD AND PATIENTS: We performed a prospective study on 41 children admitted for viral neuromeningeal infections in the pediatric department of Monastir between December 2001 and November 2002. Enteroviruses were detected from cerebrospinal fluid by RT-PCR. RESULTS: This study showed that enteroviruses were responsible for 63.4% of the infections. The mean age of patients was 6.1 years. Aseptic meningitis was diagnosed in 14 cases and encephalitis in 10. The most frequent symptom was fever (61.5%), followed by seizures (42.3%), and confusion (23%). On follow-up, all patients with meningitis had recovered without sequels. Neurological complications in patients with encephalitis were epilepsy (3 cases), cerebral palsy (2 cases), and mental retardation (1 case). CONCLUSION: This study confirmed that enteroviruses were the most common cause of viral infections of the CNS. Common use of RT-PCR can have a significant impact on the outcome of patients with enterovirus infections.

[Prolonged fever in children. Retrospective study of 67 cases]. / Les fièvres prolongées de l'enfant. Etude rétrospective de 67 cas.

BACKGROUND: The first problem to face in prolonged fever is its etiologic diagnosis. Its incidence varies between 0,5 to 3% of all paediatric hospital-stay. Precise diagnosis need an extensive questionnary, complete physical examination and an algorithm of complementary exams. PURPOSE: To precise the epidemiologic profile and causes of prolonged fever in a children. POPULATION AND METHODS: Retrospective review of 67 children between two and 15 years old admitted in the general paediatrics department of the Fattouma Bourguiba university hospital in Monastir (Tunisia), for prolonged fever between 1(st) January 1988 and 31 December 1998. RESULTS: The incidence of prolonged fever was 1,02%. The mean age was seven years with female predominance. The mean fever duration was 30 days. Fever was isolated in 23,9% of cases. Fever was associated to rheumatic or respiratory signs in respectively 26,9% and 20,9% of cases. Hospital-stay was of 11 days in 50% of cases. Prominent causes were dominated by infectious diseases (56,7%) with predominance of localized infections, followed by inflammatory diseases (20,9%) with predominance of rheumatic fever and neoplasms (3%). Fever remained of unknown origin was seen in 19,4% of cases. CONCLUSION: Prolonged fever is still dominated by infectious and inflammatory diseases and depend on local epidemiological particularities. In fact we noted in this study the relative high-frequency of visceral leishmaniasis, complicated pulmonary hydatic cyst and rheumatic fever. The diagnosis approach should be based on complementary exams of first and second stage because of their high number and cost. Prognosis of fever of unknown origin is often favorable.

In vitro effect of arsenical compounds on glutathione-related enzymes.

The mechanism of arsenic toxicity is believed to be due to the ability of arsenite (As(III)) to bind protein thiols. Glutathione (GSH) is the most abundant cellular thiol, and both GSH and GSH-related enzymes are important antioxidants that play an important role in the detoxification of arsenic and other carcinogens. The effect of arsenic on the activity of a variety of enzymes that use GSH has been determined using purified preparations of glutathione reductase (GR) from yeast and bovine glutathione peroxidase (GPx) and equine glutathione S-transferase (GST). The effect on enzyme activity of increasing concentrations (from 1 microM to 100 mM) of commercial sodium arsenite (As(III)) and sodium arsenate (As(V)) and a prepared arsenic(III)-glutathione complex [As(III)(GS)(3)] and methylarsenous diiodide (CH(3)As(III)) has been examined. GR, GPx, and GST are not sensitive to As(V) (IC(50) > 50 mM), and none of the enzymes are inhibited or activated by physiologically relevant concentrations of As(III), As(III)(GS)(3), or CH(3)As(III), although CH(3)As(III) is the most potent inhibitor (0.3 mM < IC(50) < 1.5 mM). GPx is the most sensitive to arsenic treatment and GST the least. Our results do not implicate a direct interaction of As with the glutathione-related enzymes, GR, GPx, and GST, in the mechanism of arsenic toxicity. CH(3)As(III) is the most effective inhibitor, but it is unclear whether this product of arsenic metabolism is produced at a sufficiently high concentration in critical target tissues to play a major role in either arsenic toxicity or carcinogenesis.

Catalase-peroxidase (Mycobacterium tuberculosis KatG) catalysis and isoniazid activation.

Resonance Raman spectra of native, overexpressed M. tuberculosis catalase-peroxidase (KatG), the enzyme responsible for activation of the antituberculosis antibiotic isoniazid (isonicotinic acid hydrazide), have confirmed that the heme iron in the resting (ferric) enzyme is high-spin five-coordinate. Difference Raman spectra did not reveal a change in coordination number upon binding of isoniazid to KatG. Stopped-flow spectrophotometric studies of the reaction of KatG with stoichiometric equivalents or small excesses of hydrogen peroxide revealed only the optical spectrum of the ferric enzyme with no hypervalent iron intermediates detected. Large excesses of hydrogen peroxide generated oxyferrous KatG, which was unstable and rapidly decayed to the ferric enzyme. Formation of a pseudo-stable intermediate sharing optical characteristics with the porphyrin pi-cation radical-ferryl iron species (Compound I) of horseradish peroxidase was observed upon reaction of KatG with excess 3-chloroperoxybenzoic acid, peroxyacetic acid, or tert-butylhydroperoxide (apparent second-order rate constants of 3.1 x 10(4), 1.2 x 10(4), and 25 M(-1) s(-1), respectively). Identification of the intermediate as KatG Compound I was confirmed using low-temperature electron paramagnetic resonance spectroscopy. Isoniazid, as well as ascorbate and potassium ferrocyanide, reduced KatG Compound I to the ferric enzyme without detectable formation of Compound II in stopped-flow measurements. This result differed from the reaction of horseradish peroxidase Compound I with isoniazid, during which Compound II was stably generated. These results demonstrate important mechanistic differences between a bacterial catalase-peroxidase and the homologous plant peroxidases and yeast cytochrome c peroxidase, in its reactions with peroxides as well as substrates.

[Lipid peroxidation in the presence of inorganic compounds. Relation to oxidative stress mechanisms]. / Peroxydation lipidique en présence de composés inorganiques. Relation avec les mécanismes du stress oxydant.

Oxidizing activity study of inorganic compounds is based on a mechanistic approach. This approach implies research of the capacity of these materials, after interaction with molecular oxygen, to generate activated oxygen species (AOS) in aqueous medium. These electrophilic species are able to participate in oxidative stress processes and some AOS differ in their oxidizing power; highly oxidizing species (A*) and entities (P*) less oxidizing than A*. These AOS are capable of initiating linolenic acid peroxidation leading to formation of different degradation products such MDA, monoaldehydes, conjugated dienes and trienes, hydroperoxydes, and ethane. The detection of these products allows to reveal the presence of AOS. Our data show that the global assessment of lipid peroxidation should be established from the whole of formed peroxidation products and not from one type of degradation products.