A novel silent beta-thalassemia mutation in the distal CACCC box affects the binding and responsiveness to EKLF

The silent beta-thalassemia mutation, beta(+)-101C-->T, is the only mutation currently described in the distal beta-globin CACCC box. We present a novel mutation, a C-->G transversion, in the same position. Expression analysis in heterozygous subjects demonstrated that the mutation determines a 20% reduction in the output of the beta-globin gene. DNA-protein interaction and transactivation analysis correlated the decrease in the beta-globin synthesis with the reduced binding and transactivation of EKLF to the mutant promoter. These data predict that the beta-101C-->G mutation will display a silent thalassemia phenotype similar to that of the beta-101C-->T mutation.     

Autochthonous Dengue Fever,Tokyo, Japan, 2014

After 70 years with no confirmed autochthonous cases of dengue fever in Japan, 19 cases were reported during August–September 2014. Dengue virus serotype 1 was detected in 18 patients. Phylogenetic analysis of the envelope protein genome sequence from 3 patients revealed 100% identity with the strain from the first patient (2014) in Japan.     

Pathogenesis of streptococcal and staphylococcal endocarditis

Although streptococcal and S. aureus IE share the same primary site of infection, their pathogenesis and clinical evolution present several major differences. Streptococci adhere to cardiac valves with pre-existing endothelial lesions. In contrast, S. aureus can colonize either damaged endothelium or invade physically intact endothelial cells. These interactions are mediated by multiple surface adhesins, some of which have been only partially characterized. Streptococci produce surface glucans (gtf and ftf), ECM adhesins (e.g., fibronectin-binding proteins, FimA), and platelet aggregating factors (phase I and phase II antigens, pblA, pblB, and pblT), all of which have been.     

A review of staging chest CT in trunk and extremity soft tissue sarcoma

Objectives:To determine the incidence of pulmonary metastases on chest CT in trunk and extremity soft tissue sarcoma based on two size criteria, and to identify factors associated with metastases.Methods:Retrospective review of chest CT studies in patients with trunk and extremity soft tissue sarcoma over an 18-month period. Data collected included patient age/sex, tumour location, size and relationship to fascia. All chest CTs were reviewed for the presence of metastases which were diagnosed according to two size criteria: multiple nodules > 5 mm in size or multiple nodules > 10 mm in size. Follow-up CT studies were reviewed in cases initially considered indeterminate.Results:127 males and 73 females were included (mean age 57.1 years; range 10–90 years). 147 (73.5%) tumours were deep to the fascia and 53 (26.5%) superficial. Tumour size classified according to the 12 AJCC 2019 criteria was: T1 = 52, T2 = 76, T3 = 39, T4 = 33. Based on nodule size >5 mm, 73 (36.5%) patients had no metastases, 42 (21%) had metastases, while 85 (42.5%) studies were indeterminate. Based on nodule size >10 mm, 73 (36.5%) patients had no metastases, 28 (14%) had metastases, while 99 (49.5%) studies were indeterminate. Larger maximum dimension of the primary tumour was a risk factor for pulmonary metastases using both size criteria.Conclusion:The incidence of pulmonary metastases at presentation in trunk and extremity soft tissue sarcoma is 14–21%. 42.5–49.5% of chest CTs were indeterminate.Advances in knowledge:The incidence of pulmonary metastases at presentation in trunk and extremity soft tissue sarcoma is 14–21%. Indeterminate pulmonary nodules are also very common.     

Glycolipid GD3 and GD3 synthase are key drivers for glioblastoma stem cells and tumorigenicity

The cancer stem cells (CSCs) of glioblastoma multiforme (GBM), a grade IV astrocytoma, have been enriched by the expressed marker CD133. However, recent studies have shown that CD133⁻ cells also possess tumor-initiating potential. By analysis of gangliosides on various cells, we show that ganglioside D3 (GD3) is overexpressed on eight neurospheres and tumor cells; in combination with CD133, the sorted cells exhibit a higher expression of stemness genes and self-renewal potential; and as few as six cells will form neurospheres and 20–30 cells will grow tumor in mice. Furthermore, GD3 synthase (GD3S) is increased in neurospheres and human GBM tissues, but not in normal brain tissues, and suppression of GD3S results in decreased GBM stem cell (GSC)-associated properties. In addition, a GD3 antibody is shown to induce complement-dependent cytotoxicity against cells expressing GD3 and inhibition of GBM tumor growth in vivo. Our results demonstrate that GD3 and GD3S are highly expressed in GSCs, play a key role in glioblastoma tumorigenicity, and are potential therapeutic targets against GBM.Glioblastoma multiforme (GBM) is extremely infiltrative and difficult to treat, and most patients develop recurrence after therapy. Over the past decade, many studies have suggested that bulk GBM tumors harbor cancer stem cells (CSCs) (1, 2), a distinct subpopulation of cancer cells that are able to initiate new tumors efficiently, have long-term self-renewal capacity, and survive better against chemo- or radiotherapy (2–4). CD133 has become a widely used marker for the enrichment of GBM CSCs (GSCs) and other tumor types (5–10). However, recent studies have shown that CD133 is not specific for GSCs because CD133⁻ cells also possess tumor-initiating potential (11–13), indicating the need to identify more specific and exclusive markers for GSCs to facilitate our understanding of GSCs and therapeutic development against GBM. Several reports have proposed L1CAM, A2B5, integrin α6, MET, and CD15 as markers for GSCs (14–18). However, none of these protein markers could be used specifically to identify GSCs, and no study was reported with respect to glycans as potential markers, although glycan biosynthesis involves multiple genes and it is possible to create different structures in cancer progression. It is noted that ganglioside D2 (GD2) and ganglioside D3 (GD3) were found on the surface of neural stem cells (NSCs) and that stage-specific embryonic antigen 3 (SSEA3) and SSEA4 were found on embryonic stem cells and cancer cells (19–21), but there is no glycan marker found on the surface of GSCs.Gangliosides are sialic acid-containing glycosphingolipids (GSLs) that are most abundant in the nervous system (22). The expression levels and patterns of gangliosides during brain development shift from simple gangliosides, such as GM3 and GD3, to complex gangliosides, such as GM1, GD1a, GD1b, and GT1b (23, 24). Moreover, several unique ganglioside markers, including SSEA3, SSEA4, GD2, and GD3, have been identified in stem cells (19). GD3, a b-series ganglioside containing two sialic acids, is highly expressed in mouse and human embryonic NSCs (20, 25). In cancers, GD3 is highly accumulated in human primary melanoma tissues as well as in established melanoma cell lines (26), whereas human normal melanocytes express no or minimal levels of GD3 (27). Moreover, malignant gliomas contain higher levels of GD3, and its expression correlates with the degree of malignancy (28). GD3 is produced from the precursor GM3 by the activity of GD3 synthase (GD3S), which mediates the properties of CSCs through the c-MET signaling pathway and correlates with poor prognosis in triple-negative human breast tumors (29). These findings suggest that GD3 may play an important role in the transformation of normal cells into tumors, and imply that GD3 could be a cell surface marker for GSCs.This study was designed to identify glycan markers for the enrichment of GBM stem cells and then uses these enriched GBM stem cells to characterize tumorigenicity, their association with clinical GBM specimens, and their regulation in tumor progression. The results showed that GD2 and GD3 were positively stained on GBM neurospheres. We found that cells with high GD3 expression display functional characteristics of GSCs. Suppression of GD3S, a critical enzyme for GD3 synthesis, impeded neurosphere formation and tumor initiation. The expression of GD3S correlated with the grades of astrocytomas and mediated self-renewal through c-Met activation. Furthermore, a GD3 antibody was found to eliminate the GD3⁺ cells through complement-dependent cytotoxicity (CDC) in vitro and to suppress tumor growth in mice. These results suggest that GD3 could be a significant biomarker for GSCs, that CD3 could be combined with CD133 for the enrichment of GSCs, and that both GD3 and GD3S could be targets for the development of new therapies against GBM.     

Effectiveness of near-peer simulation for managing the acutely deteriorating patient among residents of an internal medicine junior residency programme

INTRODUCTIONNear-peer teaching is gaining popularity as a teaching modality, as it improves the learner’s understanding, is targeted at an appropriate level and promotes familiarisation. This study was initiated to evaluate the effectiveness of incorporating near-peer instruction into simulation-based training within a junior residency programme.METHODS42 first-year residents from an internal medicine junior residency programme were recruited. Participants underwent a simulation-based training programme conducted over five weeks. Each week involved either an emergency or acute clinical scenario. A structured questionnaire was administered prior to and after the course to compare participants’ perceived knowledge, experience and confidence in managing the clinical scenarios.RESULTSIn our study, 83% of participants agreed/strongly agreed that the scenarios were realistic. There were improvements in perceived knowledge, experience and confidence after the course. The greatest improvement was seen for experience (post-simulation: median 7.00 [interquartile range (IQR) 6.00‒8.00] vs. pre-simulation: median 5.00 [IQR 3.00–6.25]). 65% of participants were keen to help with future training.CONCLUSIONNear-peer simulation training was found to be a viable and valuable method of instruction for first-year residents for increasing experience, instilling confidence and improving perceived knowledge. Integration of such programmes within medical education curricula shows good promise of continuity, with many first-year residents inspired to organise subsequent sessions.