A novel form of short QT syndrome (SQT3) is caused by a mutation in the KCNJ2 gene

Short QT syndrome (SQTS) leads to an abbreviated QTc interval and predisposes patients to life-threatening arrhythmias. To date, two forms of the disease have been identified: SQT1, caused by a gain of function substitution in the HERG (I(Kr)) channel, and SQT2, caused by a gain of function substitution in the KvLQT1 (I(Ks)) channel. Here we identify a new variant, "SQT3", which has a unique ECG phenotype characterized by asymmetrical T waves, and a defect in the gene coding for the inwardly rectifying Kir2.1 (I(K1)) channel. The affected members of a single family had a G514A substitution in the KCNJ2 gene that resulted in a change from aspartic acid to asparagine at position 172 (D172N). Whole-cell patch-clamp studies of the heterologously expressed human D172N channel demonstrated a larger outward I(K1) than the wild-type (P<0.05) at potentials between -75 mV and -45 mV, with the peak current being shifted in the former with respect to the latter (WT, -75 mV; D172N, -65 mV). Coexpression of WT and mutant channels to mimic the heterozygous condition of the proband yielded an outward current that was intermediate between WT and D172N. In computer simulations using a human ventricular myocyte model the increased outward I(K1) greatly accelerated the final phase of repolarization, and shortened the action potential duration. Hence, unlike the known mutations in the two other SQTS forms (N588K in HERG and V307L in KvLQT1), simulations using the D172N and WT/D172N mutations fully accounted for the ECG phenotype of tall and asymmetrically shaped T waves. Although we were unable to test for inducibility of arrhythmia susceptibility due to lack of patients' consent, our computer simulations predict a steeper steady-state restitution curve for the D172N and WT/D172N mutation, compared with WT or to HERG or KvLQT1 mutations, which may predispose SQT3 patients to a greater risk of reentrant arrhythmias.     

Off-line exhaled nitric oxide measurements in children

The concentration of exhaled nitric oxide (eNO) is a useful marker of asthmatic bronchial inflammation. eNO can now be measured away from the laboratory (off-line), even in children. Short exhalation maneuvers (8 sec) and small samples (1 L) of exhaled gas are probably sufficient in children, but more information is needed about the effect of different measurement conditions. As a preliminary step before conducting epidemiological studies in schoolchildren, we investigated the effects of expiratory flow, dead space, and expiratory time on eNO concentrations collected in 1-L mylar collection bags. We studied 101 cooperative subjects (62 males) aged 5-18 years (30 healthy volunteers, 51 asthmatics, and 20 children with various other respiratory diseases) in our pulmonary function laboratory. On-line and off-line eNO were compared in a single session, and analyzed with a Sievers NOA 280 nitric oxide analyzer. For both methods of collecting expired gas, subjects did a single exhalation without breath-holding against an expiratory pressure 10 cm H(2)O. We investigated the effects of expiratory flow, dead space, and exhalation time on eNO; we also compared on-line and off-line eNO measurements, and the repeatability of both techniques at a given flow rate. Expiratory flows of 58 mL/sec provided more reproducible data than lower flows (coefficient of repeatability 1.1 ppb for 58 mL/sec vs. 2.8 for 27 mL/sec vs. 5.7 for 18 mL/sec). eNO concentrations were about 25% higher in off-line than in on-line recordings if the initial 250 mL of exhaled gas were not eliminated, and 37% higher if exhalation lasted longer (16 sec vs. 8 sec). Eliminating 250 mL of dead space and shortening the filling time to 8 sec yielded off-line eNO values close to those on-line (geometric mean off-line eNO 14.4 ppb, 95% confidence interval: 12.2-17.0) vs. on-line eNO 13.8 ppb (95% confidence interval: 11.6-16.5). On-line and off-line results were highly correlated (r = 0.996, P = 0.000) and had similar coefficients of variation (on-line eNO 2.6%, off-line 2.8%). Neither agreement nor repeatability of eNO measurements were affected by disease status or baseline FEV(1) (% predicted values). Once standardized, the off-line eNO technique using 1-L gas collection bags will provide results similar to those recorded on-line.     

A new member of the tumor necrosis factor/nerve growth factor receptor family inhibits T cell receptor-induced apoptosis

By comparing untreated and dexamethasone-treated murine T cell hybridoma (3DO) cells by the differential display technique, we have cloned a new gene, GITR (glucocorticoid-induced tumor necrosis factor receptor family-related gene) encoding a new member of the tumor necrosis factor/nerve growth factor receptor family. GITR is a 228-amino acids type I transmembrane protein characterized by three cysteine pseudorepeats in the extracellular domain and similar to CD27 and 4-1BB in the intracellular domain. GITR resulted to be expressed in normal T lymphocytes from thymus, spleen, and lymph nodes, although no expression was detected in other nonlymphoid tissues, including brain, kidney, and liver. Furthermore, GITR expression was induced in T lymphocytes upon activation by anti-CD3 mAb, Con A, or phorbol 12-myristate 13-acetate plus Ca-ionophore treatment. The constitutive expression of a transfected GITR gene induced resistance to anti-CD3 mAb-induced apoptosis, whereas antisense GITR mRNA expression lead to increased sensitivity. The protection toward T cell receptor-induced apoptosis was specific, because other apoptotic signals (Fas triggering, dexamethasone treatment, or UV irradiation) were not modulated by GITR transfection. Thus, GITR is a new member of tumor necrosis factor/nerve growth factor receptor family involved in the regulation of T cell receptor-mediated cell death.     

Role of GITR in activation response of T lymphocytes

In this study, we describe the generation and characterization of mice in which GITR gene (TNFRSF18 [tumor necrosis factor receptor superfamily 18]), a member of the TNFRSF expressed mainly on T lymphocytes, has been ablated (GITR(-/-) mice). Results indicate that GITR inactivation does not impair the normal development of the lymphoid organs but modulates T-cell activation. In fact, when GITR(-/-) T lymphocytes are activated by treatment with an anti-CD3 monoclonal antibody they proliferate more than wild-type cells. Moreover, activated GITR(-/-) T lymphocytes express higher levels of interleukin-2 receptor, produce larger amounts of interleukin-2, and are more sensitive to activation-induced cell death than controls. These results suggest that GITR is involved in the regulation of T-cell receptor/CD3-driven T-cell activation and programmed cell death.     

Modulation of tumor immunity: a patent evaluation of WO2015026684A1

A high percentage of regulatory T cells (Tregs) among tumor-infiltrating lymphocytes weakens the immune response against tumors. The anergy of effector T cells (Teff) can be reversed by immune checkpoint treatment, which inhibits Tregs and boosts the activation of Teff. Both effects can be obtained by triggering the glucocorticoid-induced TNF receptor-related (GITR), a costimulatory molecule expressed by Teff and Tregs, and by inhibiting the programmed cell death (PD)-1 receptor, an inhibitory molecule expressed by Teff. Patent W02015026684A1 provides a method of treating human tumors using a combination of a molecule triggering GITR and another inhibiting PD-1. The treatment approach was tested on three murine models of cancer, and the synergic effect of antihuman antibodies (Abs) in combination was tested in mixed lymphocyte reactions. Immune checkpoint treatment can break tolerance toward tumors and promote tumor rejection. The patented approach is very interesting and might be successful. The combined use of PD-1 antagonists and GITR agonists is synergic and tumor-centered, and adverse events might be less problematic than expected. A crucial point in translating the murine studies to humans is the differences between murine and human GITR and the evidence that some antihuman GITR Abs are not agonists.     

Elastin-proteoglycans association revealed by cytochemical methods

By using various cytochemical stains, proteoglycans are shown to be present inside elastic fibers in aortas of beta-aminopropionitrile-induced lathyritic chicks. Depending on the characteristics of the dyes, the shape, size and distribution of the proteoglycan-revealing precipitates are described. The monocationic dye toluidine blue O and the tetracationic dye Alcian blue in the presence of 0.3 M MgCl2 give the most detailed results. With these stains the proteoglycans inside lathyritic elastin appear to be lateral branches of matrix proteoglycans, lying on the external surface of the elastic fibers. A possible general biological significance of elastin-proteoglycan association is briefly discussed.     

Role of antigen-presenting cells in cross-priming of cytotoxic T lymphocytes by apoptotic cells.

Although the mechanisms regulating recognition and phagocytosis of apoptotic cells by scavenger cells are the subject of intense investigation, little is known about the fate of the antigens contained in apoptotic cells and the constraints defining their immunogenicity. We developed a model in C57BL/6 mice to evaluate whether phagocytosis of apoptotic tumor cells yielded antigens able to get access to the MHC class I pathway and activate a specific cytotoxic T lymphocyte response. Our results demonstrate that apoptotic tumor cells are antigenic in vitro and can be immunogenic in vivo. Their immunogenicity depends on the number of cells used for immunization and the antigen-presenting cells involved in processing and presentation of antigens contained in the dying cells. The demonstration of the immunogenicity of apoptotic cells may have direct implications both in autoimmunity and cancer.     

Familial Ehlers-Danlos Syndrome Type II: Abnormal Fibrillogenesis of Dermal Collagen

We examined a father and son affected by Ehlers-Danlos syndrome type II. Both patients had micrognathia together with ligament and skin hyperlaxity. The son exhibited complete cleft palate. Ultrastructural studies revealed abnormal collagen fibrils in the dermis of both patients. In the child the most striking alterations consisted of lateral fusion of an enormous number of collagen fibrils giving rise to huge polymorphic collagen masses. In the father's dermis the great majority of collagen fibrils appeared normal; however, lateral fusion of fibrils together with local abnormal collagen aggregation were occasionally seen. In both patients the dermal elastic network was well developed and elastic fibers appeared normal.     

Epidemiology of atopy patch tests with food and inhalant allergens in an unselected population of children

Atopy patch test (APT) has been used as a diagnostic tool in patients with suspected food or inhalant allergy. This study assessed the prevalence of positive APT with food or inhalant allergens in an unselected population of schoolchildren. We also evaluated the link between positive APT reactions and skin‐prick tests (SPT) for food and inhalant allergens, circulating eosinophils and histamine skin reactivity. We studied an unselected population of 380 children aged 9 or 13 yr living in Rome, Italy. APTs were carried out with food (native or standardized) and inhalant allergens. All the children also underwent skin‐prick testing with five common inhalant and four food allergens. We also measured eosinophil cell counts and histamine skin reactivity. The prevalence of positive APT reactions for foods in unselected children ranged between 4% and 11% for hen’s egg, tomato, and wheat flour and was similar for both age groups studied. The prevalence of positive APT for milk was significantly lower in children aged 13 than in children aged 9 (p = 0.013). No concordance emerged between positive APT and SPT for foods. Conversely, APT and SPT for inhalant allergens yielded statistically significant concordance (p < 0.001). APT produces positive reactions for food or inhalant allergens in a significant number of subjects in the general population of schoolchildren. Age influences the prevalence of positive APTs with cow’s milk to some extent. Inhalant allergens probably induce a positive APT reaction through an immunoglobulin E‐linked process, while food allergens probably do not.     

Retrospective comparison of pregnancy outcomes of fresh and frozen-warmed single blastocyst transfer: a 5-year single-center experience

Journal of Assisted Reproduction and Genetics - To assess whether live birth rates (LBR) and maternal/neonatal complications differed following single fresh and frozen-warmed blastocyst transfer....