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Type III secretion systems (T3SSs) are adopted by pathogenic bacteria for the transport of effector proteins into host cells through the translocon pore composed of major and minor translocator proteins. Both translocators require a dedicated chaperone for solubility. Despite tremendous efforts in the past, structural information regarding the chaperone-translocator complex and the topology of the translocon pore have remained elusive. Here, we report the crystal structure of the major translocator, AopB, from Aeromonas hydrophila AH-1 in complex with its chaperone, AcrH. Overall, the structure revealed unique interactions between the various interfaces of AopB and AcrH, with the N-terminal "molecular anchor" of AopB crossing into the "N-terminal arm" of AcrH. AopB adopts a novel fold, and its transmembrane regions form two pairs of helical hairpins. From these structural studies and associated cellular assays, we deduced the topology of the assembled T3SS translocon; both termini remain extracellular after membrane insertion.

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BACKGROUND Glioblastomas (GBMs) are aggressive brain tumors despite radiation therapy (RT) to 60 Gy and temozolomide (TMZ). Spectroscopic magnetic resonance imaging (sMRI), which measures levels of specific brain metabolites, can delineate regions at high-risk for GBM recurrence not visualized on contrast-enhanced (CE) MRI. We conducted a clinical trial to assess the feasibility, safety and efficacy of sMRI-guided RT dose escalation to 75 Gy for newly-diagnosed GBMs. METHODS Our pilot trial (NCT03137888) enrolled patients at 3 institutions (Emory U, U Miami, Johns Hopkins U) from 9/2017 to 6/2019. For RT, standard tumor volumes based on T2-FLAIR and T1w-CE MRIs with margins were treated in 30 fractions to 50.1 and 60 Gy, respectively. An additional high-risk volume based on residual CE tumor and Cho/NAA (on sMRI) ≥ 2x normal was treated to 75 Gy. Survival curves were generated by the Kaplan-Meier method. Toxicities were assessed according to CTCAE v4.0. RESULTS Thirty patients were treated on study. Median age was 59 years. 30% were MGMT promoter hypermethylated; 7% harbored IDH1 mutation. With a median follow-up of 21.4 months for censored patients, median OS and PFS were 23.0 and 16.6 months, respectively. This regimen appeared well-tolerated with 70% of grade 3 or greater toxicity ascribed to TMZ and 23% occurring at least one year after RT. CONCLUSION Dose-escalated RT to 75 Gy guided by sMRI appears feasible and safe for patients with newly-diagnosed GBMs. OS outcome is promising and warrants additional testing. Based on these results, a randomized phase II trial is in development.

Histone deacetylases regulate a wide variety of cellular functions and have been implicated in redifferentiation of various tumors. Histone deacetylase inhibitors (HDACi) are potential pharmacologic agents to improve outcomes for patients with gliomas. We assessed the therapeutic efficacy of belinostat (PXD-101), an HDACi with blood–brain barrier permeability. Belinostat was first tested in an orthotopic rat glioma model to assess in vivo tumoricidal effect. Our results showed that belinostat was effective in reducing tumor volume in the orthotopic rat glioma model in a dose-dependent manner. We also tested the antidepression activity of belinostat in 2 animal models of depression and found it to be effective. Furthermore, we confirmed that myo-inositol levels improved by belinostat treatment in vitro. In a human pilot study, it was observed that belinostat in combination with chemoradiation may delay initial recurrence of disease. Excitingly, belinostat significantly improved depressive symptoms in patients with glioblastoma compared with control subjects. Finally, spectroscopic magnetic resonance imaging of 2 patient cases from this pilot study are presented to indicate how spectroscopic magnetic resonance imaging can be used to monitor metabolite response and assess treatment effect on whole brain. This study highlights the potential of belinostat to be a synergistic therapeutic agent in the treatment of gliomas.

Various techniques have been described for quantitating IgG or complement (C3) on red cells (RBCs). The techniques either are cumbersome, as the complement consumption test, or use radioactivity. This paper describes an antiglobulin consumption assay using an enzyme-linked immunosorbent method that can be used to quantitate IgG, IgM, and C3. With this technique RBCs from normal, healthy donors gave a mean value of 106 +/- 60 molecules of IgG per RBC, 4.5 +/- 3 molecules of IgM per RBC, and 37 +/- 28 molecules of C3 per RBC, respectively. The RBCs of hospital patients, particularly of those with infections or inflammatory conditions, contain increased amounts of nonspecifically bound immunoproteins. The availability of a common method to quantitate RBC-associated IgG, IgM, and C3 allows easy monitoring or study of the immune mechanism of autoimmune hemolytic anemia.

The population in Singapore is predominantly Asian, with Chinese forming the major ethnic group. The incidence of haemolytic disease of the newborn (HDN) due to Rh incompatibility is very low. The true incidence of HDN due to ABO incompatibility is unknown. Early discharge is practised in Singapore making it important to predict severe HDN due to ABO incompatibility as this would constitute the main cause of haemolysis next to G6PD deficiency. One thousand, six hundred and eight baby‐maternal pairs were typed for ABO, Rh, and tested for direct Coombs’test, maternal titre, cord bilirubin and haptoglobin levels. Two hundred and fifty‐one were found to be ABO incompatible, with 141 group A and 110 group B babies. The incidence of HDN due to ABO incompatibility was 3.7% of all group O mothers. Coombs’test, maternal antibody titre, cord bilirubin and haptoglobin levels were of low predictive value for severe HDN due to ABO incompatibility. The data further support the notion that it is not cost effective to screen for ABO incompatibility.

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