Leishmania infantum 5'-Methylthioadenosine Phosphorylase presents relevant structural divergence to constitute a potential drug target.

BACKGROUND: The 5'-methylthioadenosine phosphorylase (MTAP), an enzyme involved in purine and polyamine metabolism and in the methionine salvage pathway, is considered as a potential drug target against cancer and trypanosomiasis. In fact, Trypanosoma and Leishmania parasites lack de novo purine pathways and rely on purine salvage pathways to meet their requirements. Herein, we propose the first comprehensive bioinformatic and structural characterization of the putative Leishmania infantum MTAP (LiMTAP), using a comparative computational approach. RESULTS: Sequence analysis showed that LiMTAP shared higher identity rates with the Trypanosoma brucei (TbMTAP) and the human (huMTAP) homologs as compared to the human purine nucleoside phosphorylase (huPNP). Motifs search using MEME identified more common patterns and higher relatedness of the parasite proteins to the huMTAP than to the huPNP. The 3D structures of LiMTAP and TbMTAP were predicted by homology modeling and compared to the crystal structure of the huMTAP. These models presented conserved secondary structures compared to the huMTAP, with a similar topology corresponding to the Rossmann fold. This confirmed that both LiMTAP and TbMTAP are members of the NP-I family. In comparison to the huMTAP, the 3D model of LiMTAP showed an additional α-helix, at the C terminal extremity. One peptide located in this specific region was used to generate a specific antibody to LiMTAP. In comparison with the active site (AS) of huMTAP, the parasite ASs presented significant differences in the shape and the electrostatic potentials (EPs). Molecular docking of 5'-methylthioadenosine (MTA) and 5'-hydroxyethylthio-adenosine (HETA) on the ASs on the three proteins predicted differential binding modes and interactions when comparing the parasite proteins to the human orthologue. CONCLUSIONS: This study highlighted significant structural peculiarities, corresponding to functionally relevant sequence divergence in LiMTAP, making of it a potential drug target against Leishmania.

Primary adrenal lymphoma.

Primary non-Hodgkin's lymphoma of the adrenal gland is rare. We report the case of a 56-year-old patient suffering from B symptoms. The CT scan showed a bilateral adrenal mass without any lymph nodes. Scan-guided biopsies led to the diagnosis of diffuse large B-cell lymphoma. The medullar biopsy eliminated a secondary lymphoma. The patient was treated by immunochemotherapy with a complete response before autologous stem cell transplantation.

The World Psychiatry Exchange Program in Iran: a unique academic and personal experience.

The World Psychiatry Exchange Program in Iran is an academic experience we are delighted to share. As two participating early career psychiatrists, a local psychiatry faculty member manager, and the lead founder and international coordinator of the programme, we focus in this article on the unfolding of this new learning experience, the difficulties we encountered and the main lessons learned by the participants: commonalities and differences in training and practice in general adult psychiatry and child psychiatry in Tunisia and Iran, as well as in idioms of distress between the Arab and Persian cultures.

[Dysfibrinogenemia and thrombosis. A case report]. / Association dysfibrinogénémie et thrombose. A propos d'un cas.

BACKGROUND: Congenital dysfibrinogenemia is a functional disorder of the fibrinogen that represents a rare cause of thrombophilia. AIM: To report a Tunisian case of the association dysfibrinogenemia and thrombosis. CASE: A woman with inherited dysfibrinogenemia associated with mild tendency to bleeding experienced a deep vein thrombosis of the lower-extremity at 26 years of age and a fatal pulmonary embolism a few years later. Paradoxically coagulation function of fibrinogen was markedly altered in vitro with a significantly prolonged prothrombin time, activated partial thromboplastin time and thrombin time, a functional fibrinogen level that was undetected and a severely impaired fibrin polymerisation. The thromboembolic events in the patient could be related to dysfibrinogenemia since the main causes of thrombophilia were excluded. CONCLUSION: Although it is rare, this cause of thrombophilia must not be misdiagnosed, systematic measuring of prothrombin time, activated partial thromboplastin time and functional fibrinogen might be helpful.

[Cytology and immunophenotype feautures of 80 acute myeloid leukemia]. / Caracteristiques cytologiques et immunophenotypiques de 80 leucemies aigues myeloides.

Acute myeloid leukemia (AML)'s diagnosis is clinical and biological. We report here 80 AML with cytology and immunophenotype features to establish correlations. 21 AML1, 23 AML2, 12 AML3, 2 AML4, 18 AML5 and 3 AML6 were diagnosed by cytology. Only one case of AML0 was diagnosed by immunophenotype. Myelogysplasia is present in 29.8% cases. CD19 and CD56 expression was significantly associated to AML +t(8;21). Additionally, concomitant negativity of CD34 and HLA-DR was discrimininatif to AML3 diagnosis. Prognostic value to expression some CD needs time backwards.

[Tumor lysis syndrome]. / Syndrome de lyse tumorale.

Tumor lysis syndrome is a potentially life threatening oncologic emergency that requires immediate medical intervention. The syndrome results from the destruction (or lysis) of a large number of rapidly dividing malignant cells spontaneously or during chemotherapy. The resulting metabolic abnormalities include hyperkaliemia, hyperuricemia, and hyperphosphatemia with secondary hypocalcemia, all of which put patients at risk for renal failure and alteration in cardiac function. The tumor lysis syndrome occurs most often in patients with large tumor burdens that are very sensitive to chemotherapy and radiotherapy, such as acute or chronic leukaemias with high leukocyte counts and high-grade lymphoma. The current standard management for tumor lysis syndrome consists of allopurinol or recombinant urate oxidase for high risk patient in conjunction with i.v. hydratation with or without alkalinization.

[Hemoglobin C disease: report of 16 Tunisian cases]. / L'hemoglobinose C: a propos de 16 cas Tunisiens.

AIM: was to provide the clinical and biological patterns hemoglobine disease in Tunisia. METHODS: This retrospective study collected to 16 cases of hemoglobin C disease : 6 homozygotic Hb C and 10 heterozygotic Hb C/beta-thalassemia. RESULTS: The clinical profile is characterized by mild hemolytic anemia (Hb = 11.7 g/dl) associated with splenomegaly and hypersplenism. Contrary to homozygous state, the Hb C/beta-thalassemia is associated with microcytosis and pseudopolycythemia. The diagnosis is based on target cells, specific intraerythrocytic Hb C crystals in blood smear and Hb C level at 100%. CONCLUSION: The Hb C disease must be considered as a benign hemoglobinopathy which is associated with a long survival without major complications.

Megaloblastic anemia in North Africa.

We prospectively studied 478 patients with megaloblastic anemia living in Tunisia. Overall, 98% of patients had vitamin B12 deficiency. Pernicious anemia accounted for most of these cases, and median age at presentation was 45 years. Megaloblastic anemia occurred in 19 subjects under 15 years of age, and of these, nine had the Immerslund-Graesbeck syndrome.

[Pseudotumor cerebri with all-trans retinoic acid. A case report]. / Pseudotumeur cerebrale secondaire au traitement par l'acide transretinoïque. A propos d'un cas.

The diagnosis of pseudotumor cerebri (PC) is based on the triad of: (1) papilledema, (2) elevated intracranial pressure with a normal cerebrospinal constituency and (3) normal central nervous system imaging studies. It is an uncommon complication of all-trans-retinoic acid (ATRA) therapy in children treated for acute promyelocytic leukaemia (APL). Its occurrence is rare among adult patients with APL and treated with ATRA . We report a case of an adult with APL who developed PC during induction therapy with ATRA-PC was managed with repeated lumbar punctures and corticotherapy.

[Therapeutic results with apl 93 protocol in acute promyelocytic leukemia (34 cases)]. / Resultats therapeutiques dans les leucemies aigues promyelocytaires (34 cas).

BACKGROUND: Acute promyelocytic leukaemia (APL) account for approximately 10% to 15% of all AML in most reports. Clinical features includes the presence in 80% to 90% of patients of a severe hemorrhagic syndrome, a specific balanced translocation between chromosomes 15 and 17 with a fusion of a large pert of the retinoic acid receptor a gene (RARa) on chromosome 17 to a part of the promyelocytic leukaemia (PML) gene on chromosome 15. More than 75% of patients (under 65 years of age) can be cured, with the application of a combination of anthracyclines and all-trans retinoic acid (ATRA), followed by maintenance therapy. AIM: of the study was to assess of the therapeutic management of APL 93 protocol in acute promyelocytic leukemia. METHODS: We present here the results of a retrospective study concerning 34 patients with APL included between 1998 and 2004 in the APL 93 protocol : 20 in group B and 14 in group C. CR was 82 %. RESULTS: Failure is only due to toxic death (18%) Event free survival at 4 years is 63,47% with relapse rate at 14.25%. Overall survival at 4 years is 69,72%. Our results are acceptable and can be improved with reduction of failure due to toxic death, probably with omission of cytarabine from induction and consolidation adapted by the Spanish PETHEMA Group.

[Alpha interferon in children with Philadelphia chromosome-positive chronic myeloid-leukaemia]. / Les resultats de l'interferon alpha dans le traitement de la leucemie myeloide chronique de l'enfant. A propos de 5 cas.

The present work focuses on the therapeutic efficacy and the toxicity of alpha interferon in patients younger than age 18 years. 5 patients younger than 18 years were treated and followed up between 1990 and 1999 at the department of haematology (Aziza Othmana Hospital) Hydroxyurea was given as initial treatment to all patients. After a median period of 8 months, these patients received alpha interferon (5 millions units/m2 once). Six months after the beginning of the alpha interferon a complete hematologic response was obtained in all patients. The median overall survival was of 66 months: 3 patients are still alive (2 patients in an advanced stage and one patient in chronic phase) and 2 patients died after transformation. The most common reported side effects of alpha interferon were asthenia, weight loss, fever, myalgia, chills and headaches--these toxic manifestations were mild and were noticed in all our patients. Myelosuppression was noted in two patients. Interferon is well tolerated in patients younger than age years 18 old, with CML. It may offer an alternative to bone marrow transplantation in children in the chronic phase of CML without histocompatible donor. The role of new agents such as STI 571 needs to be evaluated as well.

Fanconi anemia: contribution of molecular analyses to the identification of bone marrow graft donors and the study of chimerism in grafted patients.

We report on the effectiveness of molecular studies regarding Fanconi anemia (FA) for a better selection of bone marrow graft donors and for post-transplant follow up. Ten unrelated FA patients and their families were analyzed by microsatellite markers. In 9 cases, the cytogenetic investigation of potential human leukocyte antigen (HLA)-identical related donors was normal, and the molecular analyses confirmed that they were also either normal or heterozygous carriers. For 1 patient, cytogenetic analysis of an HLA-identical sibling donor yielded ambiguous results with a relatively high number of chromosomal breakages using cross-linking agents. However, genotyping of this potential donor demonstrated his heterozygous state. Nine patients have received allogeneic bone marrow transplantation from HLA-matched related donors. Microsatellite analysis showed complete chimerism (CC) in all cases. The median follow up was 54 months (range 8-144 months). One patient out of 9 with CC rejected her graft without prior detection of a transitional mixed chimerism. Among these patients, 1 died 25 months after the transplantation of a chronic graft-versus-host-disease (GVHD). We conclude that, when the cytogenetic studies are not conclusive, molecular analyses are crucial to distinguish heterozygous carriers from asymptomatic FA Tunisian patients. Molecular analyses also allowed the evaluation of hematopoietic chimerism after allogeneic bone marrow transplantation and might be of value to identify patients with a high risk for graft rejection.

Granulocytic sarcoma of the small intestine in a child without leukemia: report of a case with cytologic findings and immunophenotyping pitfalls.

BACKGROUND: Granulocytic sarcoma is a rare tumor that is often misdiagnosed as it can be confused with lymphoma. It has unique cytologic features independent of the site of the tumor and can be identified on fine needle aspiration. CASE: A 13-year old girl without a relevant medical history presented with an abdominal mass. Investigation revealed a tumor infiltrate in the small intestine and mesentery. The fine needle aspirate contained myeloid blasts with cytoplasmic granules. Immunohistochemistry on subsequent biopsy confirmed myeloid differentiation. There was no evidence of blood or bone marrow involvement suggestive of acute leukemia. The patient was well after 27 months of follow-up. CONCLUSION: Granulocytic sarcoma should be included in the differential diagnosis of any small intestine infiltrate. Cytomorphology is accurate and efficient for the diagnosis in conjunction with complete immunocytochemistry study.

[Prognostic impact of karyotype in de novo acute myeloid leukemia: study of 139 cases]. / Impact pronostique du caryotype dans les leucemies aigues myeloides: etude de 139 cas.

A group of 139 patients with de novo acute myeloid leukemia were investigated to determine the prognostic significance of karyotype on early death, complete remission, continuous complete remission and survival. There were 27 children and 112 adults. Mean age was 32 years. t(15;17) was found associated with a high rate of early death and a diploid karyotype with long continuous complete remission. The presence of a structural change was predictive of shorter survivals. The study of the prognostic impact of recurrent anomalies reveals a good prognostic impact for normal karyotype (1 year survival probability: 40%), followed by t(8;21) (1 year survival probability: 24%), and by t(15;17) (1 year survival probability: 9%).

[Bronchopulmonary aspergillosis: study of 17 cases]. / L'aspergillose broncho-pulmonaire: etude de 17 cas.

Aspergillosis is a fungic infection depending on the local or general physiologic and immunologic state of the host. We report the result of retrospective five year study (1995-1999) about 17 cases in the laboratory of Parasitology-Mycology of Rabta hospital in Tunis. Six aspergillomas were observed, they occurred after a pulmonary tuberculosis, two cases of allergic broncho-pulmonary aspergillosis described in two asthmatic patients, nine cases of invasive pulmonary aspergillosis complicating two cancers, one leukaemia, six chronic granulomatous disease. Aspergillus fumigatus is the most frequent species (67%). The clinical and biological characteristic of those will be studied, and compared with those of the literature.

High frequency of exon 15 deletion in the FANCA gene in Tunisian patients affected with Fanconi anemia disease: implication for diagnosis.

Tunisian population is characterized by its heterogeneous ethnic background and high rate of consanguinity. In consequence, there is an increase in the frequency of recessive genetic disorders including Fanconi anemia (FA). The aim of this study was to confirm the existence of a founder haplotype among FA Tunisian patients and to identify the associated mutation in order to develop a simple tool for FA diagnosis. Seventy-four unrelated families with a total of 95 FA patients were investigated. All available family members were genotyped with four microsatellite markers flanking FANCA gene. Haplotype analysis and homozygosity mapping assigned 83 patients belonging to 62 families to the FA-A group. A common haplotype was shared by 42 patients from 26 families at a homozygous state while five patients from five families were heterozygous. Among them, 85% were from southern Tunisia suggesting a founder effect. Using multiplex ligation-dependent probe amplification (MLPA) technique, we have also demonstrated that this haplotype is associated with a total deletion of exon 15 in FANCA gene. Identification of a founder mutation allowed genetic counseling in relatives of these families, better bone marrow graft donor selection and prenatal diagnosis. This mutation should be investigated in priority for patients originating from North Africa and Middle East.