A molecular study of Tunisian populations of Dugesia sicula (Plathelminthes, Tricladida) through an identification of a set of genes.

Cell regeneration is a natural repair of different types of tissue after an injury or a lesion, and is associated with asexual reproduction in some animals such as planarians. Its understanding and improvement could have repercussions for tissue repair and regeneration as far as humans are concerned. In this context, we have proceeded to an essential step, which is the identification of the genes involved in planarian regeneration in the model species. Dugesia sicula Lepori (D. sicula) is distributed around the Mediterranean Sea, and this population is found in most of Tunisian dams. The collection of identified genes is already known in other species. DjFoxG, DjPC2, DjotxA, and Cathepsin-D were identified by the PCR technique and their expression was confirmed by RT-PCR and in situ hybridization. DjFoxG gene, the FoxG1 homolog, is expressed throughout the planarian body, abundantly on stem cells. Consecutively, we choose a central nervous system (CNS) marker; the prohormone convertase 2 (DjPC2) gene. DjotxA was observed in the brain and especially in the region surrounding the eyes (visual cells). The regenerative cells of the gut of D. sicula were scored by the Cathepsin-D gene expression, which belongs to the aspartyl protease family. We found significant results through RT-PCR and In Situ Hybridization (ISH) techniques, confirming the expression of DjFoxG, DjPC2, DjotxA and Cathepsin-D genes in our specimens.

Distal renal tubular acidosis in a Libyan patient: Evidence for digenic inheritance.

AIM OF THE STUDY: Recent advances in understanding the underlying molecular mechanism for distal renal tubular acidosis (dRTA), led to an increased attention towards the primary and the familial forms of the disease. Mutations in ATP6V1B1 and ATP6V0A4 are usually responsible for the recessive form of the disease. Mutations in gene AE1 encoding the Cl-/HCO3- exchanger, usually present as dominant dRTA, but a recessive pattern has been recently described. Our objective is to identify the mutational spectrum responsible of dRTA in a consanguineous Libyan family. MATERIALS AND METHODS: Both ATP6V0A4 and ATP6V1B1 genes were preferentially screened in our patient. Additional whole exome sequencing (WES) in the same patient, offered a wider view on potential chromosomal rearrangements as well as the mutational spectrum of other genes involved in this disease. RESULTS: The patient is a heterozygote for two different mutations, one in each of the genes ATP6V0A4 and ATP6V1B1, while no deleterious variation was detected in the remaining genes responsible for the recessive form of dRTA. Homozygosity mapping and WES confirmed our findings and supported the hypothesis of a digenic inheritance model existing as an explanation for dRTA. CONCLUSIONS: To our knowledge, this is the first report describing a Libyan patient with dRTA who suffered from early-onset sensorineural hearing loss, with a digenic mode of inheritance, supported by the identification of two novel mutations. This study increases the understanding of how dRTA is genetically transmitted, while offers a good outline towards the molecular diagnostics and genetic counseling for dRTA in Lybians.

Technological Implications of Modifying the Extent of Cell Wall-Proanthocyanidin Interactions Using Enzymes.

The transference and reactivity of proanthocyanidins is an important issue that affects the technological processing of some fruits, such as grapes and apples. These processes are affected by proanthocyanidins bound to cell wall polysaccharides, which are present in high concentrations during the processing of the fruits. Therefore, the effective extraction of proanthocyanidins from fruits to their juices or derived products will depend on the ability to manage these associations, and, in this respect, enzymes that degrade these polysaccharides could play an important role. The main objective of this work was to test the role of pure hydrolytic enzymes (polygalacturonase and cellulose) and a commercial enzyme containing these two activities on the extent of proanthocyanidin-cell wall interactions. The results showed that the modification promoted by enzymes reduced the amount of proanthocyanidins adsorbed to cell walls since they contributed to the degradation and release of the cell wall polysaccharides, which diffused into the model solution. Some of these released polysaccharides also presented some reactivity towards the proanthocyanidins present in a model solution.

Molecular investigation of distal renal tubular acidosis in Tunisia, evidence for founder mutations.

BACKGROUND: Distal renal tubular acidosis (dRTA) is a rare genetic disease caused by mutations in different genes involved in the secretion of H+ ions in the intercalated cells of the collecting duct. Both autosomal dominant and recessive forms have been described; the latter is also associated with sensorineural hearing loss. METHODS: Twenty-two Tunisian families were analyzed for mutations in the ATP6V1B1 and ATP6V0A4 genes by direct sequencing. Dating of the founder mutations was performed. RESULTS: Two founder mutations in the ATP6V1B1 gene were found in 16/27 dRTA cases. The p.Ile386Hisfs*56 founder mutation was estimated to be older than 2400 years and no correlations were found with deafness. For the remaining patients, two mutations in the ATP6V0A4 gene, one of them being novel, were found in three Tunisian cases. The presence of a heterozygous missense mutation p.T30I, of the ATP6V1B1 gene, was identified in six patients, while no mutations of the second gene were detected. No deleterious mutations of either ATP6V1B1 or ATP6V0A were found for the two probands. CONCLUSION: Our study gives evidence of phenotypic and genotypic heterogeneity of dRTA in the Tunisian population. Five different mutations were found, two of them were due to a founder effect, and screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA.

[Hepatopulmonary syndrome and portal hypertension]. / Syndrome hepatopulmonaire et hypertension portale.

BACKGROUND: The hepatopulmonary syndrome is known by the association of chronic hepatopathy and refractory hypoxemia linked to pulmonary vasodilatation. The hepatopathy may be an hepatic cirrhosis, a congenital porto-case shunt, a porte cavernous angioma or a portal high blood pressure. AIM: Report new cases CASE REPORT: We report the observation of a girl followed from the age of 5 years for type I auto-immune hepatitis complicated of portal high blood pressure, in whom the hepatopulmonary syndrome appears 6 years later and the diagnosis was established in front of the presence of clinical signs (cyanosis and fingers clubbing) associated to a severe hypoxia at 43 mmHg without heart attack and in front of the results of scintigraphy use with albumine micro-agregat marked to technetium 99 m which objected an increase of perfusion at the lungs and an extra pulmonary fixation (cerebral, thyroïdien and renal). In front of the severity of hypoxia and the intensity of the extra pulmonary fixation which corresponds the importance of the shunts, the hepatic transplantation shouldn't be realized and the child followed only a salt-free diet associated to a martial addition and to treatment by propanolol. CONCLUSION: The hepatopulmonary syndrome is a diagnosis to evocate in front of all hypoxia happening during the evolution of a chronic hepatopathy with portal high blood pressure. Its prognosis is severe in the absence of a hepatic transplantation.

[Vasculitis with renal involvement and antineutrophil cytoplasmic antibodies (ANCA) in a child receiving benzylthiouracil]. / Vascularite avec atteinte rénale et anticorps anticytoplasme des polynucléaires neutrophiles (ANCA) après prise de benzylthio-uracile chez l'enfant.

Vasculitis associated to antineutrophil cytoplasmic antibodies (ANCA) is a rare complication of therapy with antithyroid medication. They were mainly described in patients treated with propylthiouracil (PTU), carbimazole, methimazole and rarely by benzylthiouracil (Basden). We report a case of 12-years-old girl treated by benzylthiouracil for Grave's disease who developed after 2 years vasculitis associated with cutaneous involvement (generalized ulcer necrotic purpura) and glomerulonephritis with proteinuria of 24 hours at 26 mg/kg/day, microscopic hematuria and renal failure with creatinemia level at 135 micromol/l. The ANCA type antiMPO (myeloperoxidase) was positive. The histology study of the renal needle biopsy was in favour with focal necrotizing glomerulonephritisand crescents with different evolutive stages. The discontinuation of benzylthiouracil and the treatment by the corticoids involved a disappearance of cutaneous lesions, a negative result of proteinuria, a normalization of the renal function (creatinemia=84 micromol/l) and a disappearance of hematuria and ANCA. These results permitted to announce hypothesis that benzylthiouracil was implicated in development of vasculitis associated to ANCA.