Growth of single-layer boron nitride dome-shaped nanostructures catalysed by iron clusters.

We report on the growth and formation of single-layer boron nitride dome-shaped nanostructures mediated by small iron clusters located on flakes of hexagonal boron nitride. The nanostructures were synthesized in situ at high temperature inside a transmission electron microscope while the e-beam was blanked. The formation process, typically originating at defective step-edges on the boron nitride support, was investigated using a combination of transmission electron microscopy, electron energy loss spectroscopy and computational modelling. Computational modelling showed that the domes exhibit a nanotube-like structure with flat circular caps and that their stability was comparable to that of a single boron nitride layer.

The formation of the smallest fullerene-like carbon cages on metal surfaces.

The nucleation and growth of carbon on catalytically active metal surfaces is one of the most important techniques to produce nanomaterials such as graphene or nanotubes. Here it is shown by in situ electron microscopy that fullerene-like spherical clusters with diameters down to 0.4 nm and thus much smaller than C60 grow in a polymerized state on Co, Fe, or Ru surfaces. The cages appear on the surface of metallic islands in contact with graphene under heating to at least 650 °C and successively cooling to less than 500 °C. The formation of the small cages is explained by the segregation of carbon on a supersaturated metal, driven by kinetics. First principles energy calculations show that the clusters polymerize and can be attached to defects in graphene. Under compression, the polymerized cages appear in a crystalline structure.

Epidemiological, clinical and laboratory features of murine typhus in central Tunisia.

OBJECTIVE: Murine typhus is an endemic zoonosis. It is difficult to diagnose because of its non-specific clinical manifestations. Our objective was to describe the epidemiological, clinical, laboratory, and treatment features of murine typhus. METHODS: We conducted a retrospective study of 73 adult patients hospitalized for murine typhus from 2006 to 2011. The diagnosis was confirmed by a single titer of IgM≥128 or by seroconversion to typhus group antigen identified by indirect fluorescent assay. RESULTS: The mean age of patients was 33.1 years (range, 13-68 years). Thirty-eight patients (52%) lived in rural or suburban areas; neither fleabites nor exposure to rats were reported. The most common clinical symptoms were: fever, headache, and myalgia. A maculopapular and non-confluent rash was observed in 47 patients (64.4%). No inoculation eschar was observed in any patient. Eight patients presented with interstitial pneumonia and two with lymphocytic meningitis. The diagnosis was confirmed by indirect fluorescence assay in every case. A single titer of IgM ≥ 128 was found in 62 (84.9%) cases. The other 11 cases were diagnosed by seroconversion. All patients were given antibiotics. Tetracyclines were prescribed in 57 cases (78%). The two patients presenting with meningitis were treated with fluoroquinolone. The outcome was favorable for all patients and no relapse was observed. CONCLUSION: The features of murine typhus are non-specific. The definitive diagnosis is based on serologic testing by indirect fluorescent assay. Cyclins were the most prescribed antibiotics.

Rhino-orbito-cerebral mucormycosis: five cases.

INTRODUCTION AND OBJECTIVE: Mucormycosis is an invasive fungal infection usually observed in immunocompromised patients. Mucormycosis is rapidly fatal without an early diagnosis and treatment. We report five patients of rhino-orbital-cerebral mucormycosis and a literature review. DESIGN: The medical records of five patients presenting with rhino-orbital-cerebral mucormycosis, admitted between January 1995 and December 2007, were analyzed. All patients underwent tissue biopsy. The histologic sections revealed the presence of non-septate hyphae of the order Mucorales. RESULTS: The five patients, three men and two women, between 27 and 61 years of age, were all diabetic. The main symptoms were exophthalmia (five patients), facial swelling (four patients), periorbital cellulitis (four patients), and cranial nerve palsy (four patients). Anterior rhinoscopy revealed palatine or nasal necrotic lesions in four patients. All presented with diabetic ketoacidosis and CT scan revealed rhino-orbital-cerebral involvement in every patient. All patients were given intravenous amphotericin B. Four patients underwent surgical debridement of necrotic tissue. Two patients survived. CONCLUSIONS: Mucormycosis is usually a fatal infection in diabetic patients. Early diagnosis should be based on imaging data and histology. Amphotericin B must be rapidly initiated and associated with aggressive surgical debridement to reduce mortality.

Quatre premiers cas de meningites a Toscana Virus dans la Region de Monastir

Les meningites a Toscana Virus ont ete largement decrites en Italie ou le virus a ete isole pour la premiere fois. Actuellement; elles sont de plus en plus decrites dans le pourtour du bassin mediterraneen devenant ainsi une pathologie emergente dans cette region. Nous rapportons; dans ce travail; 4 cas de meningites a Toscana Virus hospitalises dans le service des Maladies Infectieuses de l'hopital Fattouma Bourguiba de Monastir - Tunisie; en rappelant les caracteristiques epidemiologiques; cliniques; biologiques et evolutives. Tous les malades etaient de sexe masculin; demeurant dans une region cotiere et hospitalises pendant la saison estivale. Ils etaient ages en moyenne de 26 ans (14 - 41). Le diagnostic clinique reposait sur la presence d'un syndrome meninge febrile. La ponction lombaire avait montre dans les 4 cas une meningite lymphocytaire a liquide clair avec une glycorrachie normale. La detection des IgM et des IgG dans le sang et le LCR avait permis de confirmer le diagnostic. L'evolution etait favorable sous traitement symptomatique; dans tous les cas; avec un recul de 9 mois

[Adverse effects of antitubercular drugs: epidemiology, mechanisms, and patient management]. / Les effets indésirables des antituberculeux: épidémiologie, mécanismes et conduite à tenir.

Tuberculosis, what ever its localization, is an infectious disease which can be totally cured by combining antitubercular drugs. Current therapeutic regimens with isoniazid, rifampicin, pyrazinamide, ethambutol, and streptomycin have proved successful in treating tuberculosis. However, they are associated to a high rate of adverse effects that can lead to therapeutic failure. Understanding the nature and the severity of these adverse effects allows for their appropriate management. Toxic neuropathy and hepatitis are the most common adverse reactions to isoniazid. Rifampicin is generally well tolerated but some severe immuno-allergic reactions may occur in case of intermittent regimen. Pyrazinamide-induced liver injury is rare but sometimes lethal. Joint affections, usually due to hyperuricemia, are more frequent but easily manageable. The major adverse effect related to ethambutol is ocular optic neuropathy. It occurs dose-dependently and can be irreversible. Finally, administration of streptomycin is potentially associated with renal and cochleo-vestibular toxicity that might be milder than when induced by other aminoglycosides. The management of antituberculosis-induced adverse effects depends on parameters related to the adverse effect itself and to the administrated drug.

[Meningitis revealing Rickettsia typhi infection]. / Méningite révélant une infection à Rickettsia typhi.

INTRODUCTION: Neurological manifestations are rarely observed in murine typhus. We present a case of meningitis caused by Rickettsia typhi. EXEGESIS: We report a case of Tunisian 57-year-old woman admitted for suspicion of meningitis. Clinical examination revealed fever at 39,5 degrees C and nuchal rigidity. There were no focal neurologic signs, cutaneous rash or eschar. Lumbar puncture showed clear cerebrospinal fluid containing normal glucose, 0,48 g/l protein and 30 WBC (78% lymphocyte). Gram-stained smear and culture were negative. Serology confirmed the diagnosis. The patient was initially treated by ampicillin 12 g daily but remained febrile. Retinal lesions were detected on ophthalmic examination, suggesting rickettsial infection. Clinical outcome was good after 7-day treatment with oral ciprofloxacin 1,5 g daily. The mean follow-up was six months. CONCLUSION: Murine typhus is an endemic zoonosis. Neurological manifestations were uncommon. An ophthalmic examination is recommended if rickettsiosis was suspected.

[Pulmonary thrombosis as a complication of Mediterranean spotted fever]. / Une fièvre boutonneuse méditerranéenne compliquée d'une embolie pulmonaire.

INTRODUCTION: Thromboembolic complications were uncommon in mediterranean spotted fever. OBSERVATION: We report a case of 55-years- old man who was admitted for mediterranean spotted fever. Two days later, the patient developed chest pain due to a pulmonary thrombosis confirmed by angio-CT. The outcome was good with heparin therapy. The investigation for another cause of thrombosis was negative. CONCLUSION: Mediterranean spotted fever is usually a moderately severe self-limited illness. Pulmonary thrombosis was uncommon associated with severe disease.

[Phalengeal actinomycosis: a rare disease]. / Actinomycose des os du pied: un diagnostic à ne pas méconnaître.

INTRODUCTION: Bone involvement in actinomycosis is rare. EXEGESIS: We report a case of a 38 year-old woman with foot bone actinomycosis. The clinical symptoms were non-specific and the diagnosis was difficult. An X-ray revealed an osteolysis and a sclerosis of the proximal phalanx of the big toe. A phalengiectomy was carried out after the failure of antistaphylococcic antibiotherapy. The diagnosis of actinomycosis was substantiated by a histological examination. The clinical outcome was good after six-month treatment by penicillin G substitutes for cotrimoxazol. The patient completely recovered and was feeling well. The mean follow up was fifteen months. CONCLUSION: Clinical and therapeutic aspects of this rare localization are reviewed.

[Pyogenic splenic abscesses. A review of 8 cases]. / Les abcès de la rate à pyogènes. A propos de 8 cas.

PURPOSE: Pyogenic splenic abscess is un uncommon and potentially life-threatening disease. Due to inconspicuous and nonspecific clinical picture, it remains a diagnostic challenge. Medical imaging progresses are helpful for diagnosis and treatment. METHODS: We tried to establish epidemiologic and clinical features and therapeutic possibilities of 8 cases of splenic abscesses occurred between 1993 and 2002. RESULTS: There were 5 male patients and 3 female patients. Aged ranged from 17 to 53 years, with a median of 34 years. One patient was immunocompromised (colonic carcinoma). Common clinical presentations included fever (n=8) and left upper quadrant abdominal pain (n=7). Positive blood cultures were found in only four patients (50%) : Staphylococcus aureus (3) and coagulase negative Staphylococcus (1). Staphylococcus aureus and Bacteroïdes fragilis were isolated in one abscess pus respectively. The diagnosis was obtained by ultrasonography in all 8 cases. Antibiotics were prescribed in all cases for a mean length of 60 days (30 - 110 days). Splenectomy and percutaneous CT-guided drainage were performed in one case respectively. Evolution was good in all cases. CONCLUSION: Splenic abscesses are increasingly recognized. The combination of clinical features and imaging findings, early diagnosis and treatment can be made.

[Paramedical staff knowledge and practice related to the blood transfusion safety]. / Connaissances et pratiques du personnel soignant en matière de sécurité transfusionnelle.

Blood transfusion is a complex activity, involving many actors. It is a high risk activity which couldn't be controlled without the use of specific methods. Health care workers beliefs and organisational factors are two major issues for the blood transfusion safety. Our study objectives were to describe the paramedical staff's knowledge and practice regarding blood transfusion safety and to identify factors that are related to them. We carried out a cross sectional study. The information was gathered by using a questionnaire. The latter was developed by foreign teams and adapted to the local context. Two outcome measures were used: the knowledge and practice score and the proportion of true answers. The study showed that only 15% of the interviewed persons have had a score less than 30 (scale range from 0 to 100), i.e. only 15% have had appropriate knowledge and practice with no negative consequences for the patient safety. 13.8% of the study population provided right answers related to the biologic exams required before red cells transfusion and 34% for the abnormal reaction circumstances. These results underscores the importance of strategies improving the quality and the safety of blood transfusion, i.e. the continuous medical education, implementing a blood transfusion information system and the use of transfusion practice guidelines.

[Sweet's syndrome]. / Le syndrome de Sweet.

Sweet's syndrome or acute febrile neutrophilic dermatosis is relatively frequent. It can be isolated or associated to other diseases, particularly, inflammatory or autoimmune diseases, lymphoproliferative or malignant disorders. In this retrospective study, we report 10 cases of Sweet's syndrome recorded over a 42 months period. The female predominance was net (9 womens for 1 man). The mean age was 45 years. The diagnosis was established, in all cases, on clinical, biological and histological criteria. The lesions occurred most commonly on legs (9 cases). The failure of antibiotics has been noted in all patients, and colchicine has been demonstrated efficient in 6 patients. Our study confirms the interest of cutaneous biopsy in case of papulo-nodular lesions which has not respond to antibiotics.