Congenital hypofibrinogenemia: characterization of two missense mutations affecting fibrinogen assembly and secretion

Congenital hypofibrinogenemia is a rare bleeding disorder characterized by abnormally low levels of fibrinogen in plasma, generally due to heterozygous mutations in one of the three fibrinogen genes (FGA, FGB, and FGG, coding for Aα, Bβ, and γ chain, respectively). Hypofibrinogenemic patients are usually asymptomatic, whereas individuals bearing similar mutations in the homozygous or compound heterozygous state develop a severe bleeding disorder: afibrinogenemia. The mutational spectrum of these quantitative fibrinogen disorders includes large deletions, point mutations causing premature termination codons, and missense mutations affecting fibrinogen assembly or secretion, distributed throughout the 50-kb fibrinogen gene cluster. In this study, we report the mutational screening of two unrelated hypofibrinogenemic patients leading to the identification of two missense mutations, one hitherto unknown (αCys45Phe), and one previously described (γAsn345Ser). The involvement of αCys45Phe and γAsn345Ser in the pathogenesis of hypofibrinogenemia was investigated by in-vitro expression experiments. Both mutations were demonstrated to cause a severe impairment of intracellular fibrinogen processing, either by affecting half-molecule dimerization (αCys45Phe) or by hampering hexamer secretion (γAsn345Ser).     

Italian Society of Hematology practice guidelines for the management of iron overload in thalassemia major and related disorders

New measures of iron accumulation in liver and heart (superconducting quantum inference device and magnetic resonance imaging), and oral iron chelators (deferiprone and deferasirox) are available for managing iron overload in thalassemia major. To assure appropriate use of these new health technologies, the Italian Society of Hematology appointed a panel of experts to produce clinical practice-guidelines for the management of iron overload in thalassemia major and related disorders. The analytical hierarchy process, a technique for multicriteria decision analysis, was applied to relevant key questions in order to identify the alternative strategies, generate explicit criteria for their evaluation, and check how well the alternatives fulfilled the criteria. The result of a comprehensive systematic review of articles released from 1990 to 2007 was used as a source of scientific evidence to compare the decisional options pairwise, and select the final recommendation. Every step in the model was developed from questionnaires and group discussion. The resulting recommendations advise about which examination to carry out in order to plan iron chelation therapy, when to start iron chelation, which iron chelator to choose in regularly transfused patients, how to monitor iron chelation therapy, and when and how to switch standard therapy.     

Antibody response in patients with cutaneous leishmaniasis infected by Leishmania (Viannia) braziliensis or Leishmania (Viannia) guyanensis in Brazil

The antibody response against Leishmania (Leishmania) amazonensis crude antigen was measured through the indirect immunofluorescent assay (IFA) and the immunoenzymatic assay (ELISA) in 114 patients with cutaneous leishmaniasis (CL) in Brazil. Fifty-four patients were infected by Leishmania (Viannia) braziliensis, and 60 patients had L. (V.) guyanensis infection. Patients were comparable by age, sex, disease duration and the Montenegro skin test diameter. L. (V.) braziliensis-infected patients showed significant lower number of ulcerated lesions, greater ulcerated area and higher proportion of lymph node enlargement. Sensitivity of IFA was 79.6% (95% CI 66.1-88.9) and 71.7% (95% CI 58.4-82.2) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.324). Sensitivity of ELISA was 98.2% (95% CI 88.8-99.9) and 85.0% (95% CI 72.9-92.5) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.018). Significant differences were observed in the magnitude of the antibody response before treatment with higher levels detected in L. (V.) braziliensis-infected patients by both serologic techniques. Eighty-four patients had serologic evaluations before and 12 weeks after treatment with meglumine antimoniate, 20 mg/kg/day for 20 days. Significant lower optic density values were observed after treatment with both species independent of cure or failure. Our data showed that L. (V.) braziliensis induces a higher antibody response against L. (L.) amazonensis antigens than L. (V.) guyanensis and that down-modulation of the antibody response occurs shortly during disease evolution after treatment. Moreover the data support the use of ELISA as a better tool for detection of antibodies in CL.     

Recommendations for the management of prosthetic valve thrombosis

Prosthetic valve thrombosis (PVT) is a life-threatening disease, for which treatment strategies have been controversial. Herein, existing data on management options are reviewed, and conclusions drawn as to the choice and use of treatment strategies for PVT. The use of transesophageal echocardiography (TEE) allows distinction to be made between obstructive and non-obstructive PVT by the presence or absence of occluder motion limitation. The differentiation of PVT from pannus and vegetation is, however, still limited by TEE. The incidence of PVT has been underestimated by not taking into account a large percentage of non-obstructive PVT. Although the standard treatment for PVT has been surgery, thrombolysis has lower mortality rates, particularly in patients in NYHA functional classes III-IV. The lowest complication rates with thrombolysis have been achieved in patients with non-obstructive PVT. Pregnancy, left atrial appendage thrombi and large PVT are not contraindications to thrombolysis. The third therapeutic option is anticoagulant therapy. The detrimental effect of anticoagulant treatment in obstructive PVT was shown in a prospective study. Non-obstructive thrombi of > 5 mm length have been treated with higher success rates and lower complication rates by thrombolysis than by anticoagulant treatment. In conclusion, all patients with suspected PVT should undergo multiplane TEE. Thrombolysis is the first-line treatment for obstructive PVT, independent of NYHA class and thrombus size if there are no contraindications. Serial TEE studies must be conducted during thrombolysis. Surgery should be reserved for those patients in whom thrombolysis is contraindicated, or has failed. Initial anticoagulant therapy is recommended only for small, non-obstructive PVT if anticoagulation had been subtherapeutic; otherwise, thrombolysis is the treatment of choice if there are no contraindications.     

Methylation of TIMP3 in esophageal squamous cell carcinoma

AIM： To measure the frequency of DNA methylation of the tissue inhibitor of metalloproteinase 3 （TIMP3） promoter and relate this to any change of gene expression in esophageal squamous cell carcinoma in patients from a region of high incidence in China. METHODS： Cancer cell lines were treated with or without the demethylating reagent 5-aza-2′-deoxycytidine. Methylation of the TIMP3 promoter was assessed in three regions by melt curve analysis and its expression was assessed by real-time RT-PCR. Tumors and proximal resection margins were obtained from 64 patients with esophageal squamous cell carcinoma from a region of high incidence in China. Methylation was assessed by melt curve analysis and expression by immunohistochemistry.
RESULTS： Methylation in one of the three promoter regions assessed correlated with gene silencing in esophageal cell lines. A degree of methylation of TIMP3 was found in only four esophageal squamous cell carcinomas, and partial loss of TIMP3 protein expression in just one.
CONCLUSION： Methylation and loss of expression of TIMP3 occurs infrequently in esophageal squamous cell carcinoma in a region of high incidence in China.     

Increased risk of myocardial infarction with duration of protease inhibitor therapy in HIV-infected men

BACKGROUND: In the current context of dyslipidaema, hyperglycaema and lipodystrophia observed among HIV-seropositive subjects, it is important to study the risk of myocardial infarction (MI) in this population. The French Hospital Database on HIV, which includes a large number of seropositive subjects followed for substantial periods, offers the opportunity to analyse the impact of protease inhibitors (PI) on the risk of MI among men. METHODS: Cox model was used to study the risk factors of MI occurrence. Standardized morbidity ratios (SMR) in men exposed to PI were calculated with data from the French general male population (FGMP) of the same age as reference. RESULTS: Between 1996 and 1999, MI was diagnosed in 60 men among 88 029 person-years (PY), including 49 cases among men exposed to PI. In the Cox model, exposure to PI was associated with a higher risk of MI [relative hazard (RH), 2.56; 95% confidence interval (CI), 1.03-6.34]. The expected incidence in the FGMP was 10.8/10,000 PY. The SMR relative to the FGMP was 0.8 (95% CI, 0.5-1.3) for men exposed to PI for < 18 months (G1), 1.5 (95% CI, 0.8-2.5) for men exposed for 18-29 months (G2) and 2.9 (95% CI, 1.5-5.0) for men exposed for >or= 30 months (G3). With G1 as reference, the SMR was 1.9 (95% CI, 1.0-3.1) for G2 and 3.6 (95% CI, 1.8-6.2) for G3. CONCLUSION: Our results point to a duration-related effect relationship between PI and MI, with a higher MI incidence rate among men exposed to PI for 18 months or more.     

Left bifascicular block and percutaneous mitral valvuloplasty]

In some patients, the inflation of balloons through the mitral orifice during percutaneous mitral valvuloplasties may impair intraventricular conduction. In some cases, this appears to correspond to a block of the anterior and middle network within the left branch of the bundle of His. This left "biblock" is characterized by extreme left axial deviation of AQRS, of about -60 to -70 degrees, with a QS aspect on D2 and D3, RS on V1 and R on V6 with no major prolongation of ventricular activation time. If this hypothesis is correct, it would support the "trifascicular" concept of the left branch of the bundle of His.