Central nervous system lymphoma in immunocompetent patients: The North Shore-Long Island Jewish Health System experience

Of the 74 immunocompetent patients diagnosed between July 2004 and June 2011 at the North Shore University Hospital and Long Island Jewish Medical Center with primary central nervous system lymphoma, 71 (95.9%) had diffuse large B-cell lymphomas (DLBCL). The median patient age was 68 years (range: 19–87 years) with a slight male preponderance (1.1:1). The overall median survival time was 21 months. For patients older than 70 years, the median survival time was 8 months while for those 70 years or younger, the median survival time was 27 months (p < 0.01). Female patients had a worse prognosis than male patients (p < 0.05, median survival time, 17 months compared to 23 months). We had enough data from 52 of these 71 patients to define the lymphomas as either germinal center B-cell-like (GCB) or activated B-cell-like (ABC) DLBCL. Of these 52 patients, 42 (80.8%) had ABC DLBCL while only 10 (19.2%) had GCB DLBCL. The patients in the GCB subgroup seemed to survive longer than the patients in the ABC subgroup, although the difference did not reach statistical significance. No statistically significant difference in overall survival was seen between patients with BCL-6 positive or negative DLBCL; or between patients with BCL-2 positive or negative DLBCL.     

ED breast cases and other breast emergencies

Patients with pathologic processes of the breast commonly present in the Emergency Department (ED). Familiarity with the imaging and management of the most common entities is essential for the radiologist. Additionally, it is important to understand the limitations of ED imaging and management in the acute setting and to recognize when referrals to a specialty breast center are necessary. The goal of this article is to review the clinical presentations, pathophysiology, imaging, and management of emergency breast cases and common breast pathology seen in the ED.     

Water intake and risk of type 2 diabetes: A systematic review and meta-analysis of observational studies

Background and aimsThe association of water intake with type 2 diabetes mellitus (T2DM) is still unclear. Therefore, the aim of this systematic review and meta-analysis was to synthesize the knowledge about the relationship between water intake and the risk of T2DM.MethodsWe conducted a systematic search in PubMed and Scopus up to June 2018 for observational studies. Risk ratios (RR)s and 95% confidence intervals (95% CI)s were calculated and fixed effects models were used.ResultsOverall, 6 studies were included in the meta-analyses. There was an inverse relationship between water intake and risk of T2DM (RR: 0.94; 95% CI: 0.91–0.97, P < 0.001) with low heterogeneity (I2 = 24%, P = 0.24).ConclusionOur findings indicated that the intake of water was correlated with reduced risk of type 2 diabetes in women and men. These results support the current recommendations of water intake as an inseparable part of a diet with the lowest risk of diabetes mellitus.     

The sponge/Matrigel angiogenesis assay

It has become increasingly clear that definitive tests for angiogenesis require in vivo assays. Recently, the Matrigel plug assay has become the method of choice for many studies involving in vivo testing for angiogenesis. In this assay, test angiogenesis-inducing compounds such as bFGF or tumor cells are introduced into cold liquid Matrigel which, after subcutaneous injection, solidifies and permits penetration by host cells and the formation of new blood vessels. Assessment of angiogenesis in the Matrigel plug is achieved either by measuring hemoglobin or by scoring selected regions of histological sections for vascular density. We now describe a modification of the Matrigel plug assay which permits a more precise visualization of the angiogenic reaction, provides directional information, requires no histological analysis, and lends itself to photographic documentation and image analysis protocols. We illustrate the assay by describing dose- and time-dependent responses to tumors of murine and human origin, to angiogenesis-inducing factors such as bFGF (FGF-2) and VEGF and to anti-angiogenic agents such as endostatin. The method has been used as well to demonstrate blood vessel recruitment by embryonic chick aortic arch rudiments. Additionally it has been able to detect strain-dependent differences in susceptibility to angiogenic stimulation.     

C-terminal region of activation-induced cytidine deaminase (AID) is required for efficient class switch recombination and gene conversion

Activation-induced cytidine deaminase (AID) introduces single-strand breaks (SSBs) to initiate class switch recombination (CSR), gene conversion (GC), and somatic hypermutation (SHM). CSR is mediated by double-strand breaks (DSBs) at donor and acceptor switch (S) regions, followed by pairing of DSB ends in two S regions and their joining. Because AID mutations at its C-terminal region drastically impair CSR but retain its DNA cleavage and SHM activity, the C-terminal region of AID likely is required for the recombination step after the DNA cleavage. To test this hypothesis, we analyzed the recombination junctions generated by AID C-terminal mutants and found that 0- to 3-bp microhomology junctions are relatively less abundant, possibly reflecting the defects of the classical nonhomologous end joining (C-NHEJ). Consistently, the accumulation of C-NHEJ factors such as Ku80 and XRCC4 was decreased at the cleaved S region. In contrast, an SSB-binding protein, poly (ADP)-ribose polymerase1, was recruited more abundantly, suggesting a defect in conversion from SSB to DSB. In addition, recruitment of critical DNA synapse factors such as 53BP1, DNA PKcs, and UNG at the S region was reduced during CSR. Furthermore, the chromosome conformation capture assay revealed that DNA synapse formation is impaired drastically in the AID C-terminal mutants. Interestingly, these mutants showed relative reduction in GC compared with SHM in chicken DT40 cells. Collectively, our data indicate that the C-terminal region of AID is required for efficient generation of DSB in CSR and GC and thus for the subsequent pairing of cleaved DNA ends during recombination in CSR.Activation-induced cytidine deaminase (AID) is essential for three different genetic events: class switch recombination (CSR), gene conversion (GC), and somatic hypermutation (SHM), which contribute to Ig gene diversification (1–5). Although AID generates single-strand breaks (SSBs) in the Ig genes, subsequent repair steps for CSR and GC are similar to each other but are distinct from SHM in their mechanistic properties, i.e, in (i) generation of the double-strand breaks (DSBs), (ii) recombination, and (iii) the requirement for uracil-DNA-glycosylase (UNG) for the pairing of the DSB ends (6–10). Despite the similarities between GC and CSR, their repair mechanisms have distinct features: CSR recombination requires nonhomologous end joining (NHEJ), and GC depends on homologous recombination (HR). During CSR, DSB ends normally are joined by classical NHEJ (C-NHEJ), which requires specific repair proteins such as Ku80, XRCC4, or DNA ligase IV (11, 12). In the absence of C-NHEJ, a back-up end-joining pathway called “alternative end joining” (A-EJ), which is reported to be slower and also more error prone than C-NHEJ, joins the broken DSBs ends (13). On the other hand, HR, the most common form of homology-directed repair, requires long sequence homology between donor and acceptor DNA to complete the recombination step by recruiting a distinct set of repair proteins such as RAD54, RAD52, and RAD51 to the break sites (14, 15).Various studies on AID mutations in the N-terminal or C-terminal regions (4, 8, 9, 16–19) have shown that N-terminal AID mutants are compromised for CSR and are defective in SHM, indicating that the N-terminal region of AID is required for DNA cleavage (9, 16, 19). On the other hand, the C-terminal region of AID, which contains a nuclear-export signal and is responsible for AID’s shuttling activity between the nucleus and cytoplasm, is required for CSR-specific activity but not for DNA cleavage activity and SHM (8, 16). Among the series of AID C-terminal mutants examined, two mutants show characteristic features: P20, which has an insertion of 34 amino acids at residue 182 and normal nuclear-cytoplasmic shuttling activity, and JP8Bdel, which has a 16-amino acid truncation at residue 183, accumulates in the nucleus, and shows higher DNA break activity at the donor switch (S) region (16, 17). Although several reports suggest that the C-terminal region of AID is involved in protein stability (20, 21), C-terminal mutants of AID stabilized by fusing the hormone-binding domain of estrogen receptor (ER) also show similar CSR-defective phenotypes (8). Taken together, these data suggest that the DNA cleavage activity and CSR-specific activity depend on different regions of AID (8, 19). In addition, the C-terminal region of AID is essential for the interaction of AID with poly (A)⁺ RNA via a specific cofactor (22). Because CSR requires de novo protein synthesis, we proposed that after DNA cleavage the C-terminal region of AID may be involved in the regulation of the recombination step through generation of a new protein (8, 16, 22).DSBs induced by AID during CSR ultimately are joined by the efficient DNA repair pathway that requires C-NHEJ factors such as Ku70/80 (12, 23). However, in the absence of C-NHEJ, the A-EJ pathway that relies on microhomology can join the broken DNA ends, although this pathway is associated with chromosomal translocations (11, 24). Previously, we reported that JP8Bdel enhances aberrant c-myc/IgH translocations and that it fails to carry out the efficient recombination between donor and acceptor S regions in the IgH locus (8). Therefore, it is important to examine whether the AID C-terminal mutants affect the S–S joining in CSR.In the current work we examined whether the C-terminal region of AID is involved in DNA synapse formation and recombination during CSR in CH12F3-2 and spleen B cells. We also examined the effect of AID C-terminal mutations on GC in chicken DT40 cells, which depends on HR between pseudo V genes and the downstream IgVλ region. Using these CSR- and GC-monitoring systems, we demonstrate that efficient CSR and GC require the C-terminal region of AID for the formation of DSB from SSB and subsequent end synapse. Considering these findings together, we conclude that, in addition to DNA cleavage, AID has a unique function in the generation of DSBs, which is required for S–S synapse formation and joining in CSR and recombination in GC.     

Tri-layered elastomeric scaffolds for engineering heart valve leaflets

Tissue engineered heart valves (TEHVs) that can grow and remodel have the potential to serve as permanent replacements of the current non-viable prosthetic valves particularly for pediatric patients. A major challenge in designing functional TEHVs is to mimic both structural and anisotropic mechanical characteristics of the native valve leaflets. To establish a more biomimetic model of TEHV, we fabricated tri-layered scaffolds by combining electrospinning and microfabrication techniques. These constructs were fabricated by assembling microfabricated poly(glycerol sebacate) (PGS) and fibrous PGS/poly(caprolactone) (PCL) electrospun sheets to develop elastic scaffolds with tunable anisotropic mechanical properties similar to the mechanical characteristics of the native heart valves. The engineered scaffolds supported the growth of valvular interstitial cells (VICs) and mesenchymal stem cells (MSCs) within the 3D structure and promoted the deposition of heart valve extracellular matrix (ECM). MSCs were also organized and aligned along the anisotropic axes of the engineered tri-layered scaffolds. In addition, the fabricated constructs opened and closed properly in an ex vivo model of porcine heart valve leaflet tissue replacement. The engineered tri-layered scaffolds have the potential for successful translation towards TEHV replacements.     

Application of [68Ga]PSMA PET/CT in Diagnosis and Management of Prostate Cancer Patients

Molecular Imaging and Biology - The early and accurate diagnosis of locoregional recurrence or metastasis in prostate cancer (PC) has a significant impact on treatment options. Prostatic-specific...