Somatic Alterations Contributing to Metastasis of a Castration‐Resistant Prostate Cancer

Metastatic castration‐resistant prostate cancer (mCRPC) is a lethal disease, and molecular markers that differentiate indolent from aggressive subtypes are needed. We sequenced the exomes of five metastatic tumors and healthy kidney tissue from an index case with mCRPC to identify lesions associated with disease progression and metastasis. An Ashkenazi Jewish (AJ) germline founder mutation, del185AG in BRCA1, was observed and AJ ancestry was confirmed. Sixty‐two somatic variants altered proteins in tumors, including cancer‐associated genes, TMPRSS2‐ERG, PBRM1, and TET2. The majority (n = 53) of somatic variants were present in all metastases and only a subset (n = 31) was observed in the primary tumor. Integrating tumor next‐generation sequencing and DNA copy number showed somatic loss of BRCA1 and TMPRSS2‐ERG. We sequenced 19 genes with deleterious mutations in the index case in additional mCRPC samples and detected a frameshift, two somatic missense alterations, tumor loss of heterozygosity, and combinations of germline missense SNPs in TET2. In summary, genetic analysis of metastases from an index case permitted us to infer a chronology for the clonal spread of disease based on sequential accrual of somatic lesions. The role of TET2 in mCRPC deserves additional analysis and may define a subset of metastatic disease.     

Transcultural Nursing: Current Trends in Theoretical Works

Purpose

To explore the current trends in theoretical works related to transcultural nursing through an integrated literature review.

Melatonin protects against oxidative stress in granular corneal dystrophy type 2 corneal fibroblasts by mechanisms that involve membrane melatonin receptors

Considering that oxidative stress plays a role in corneal fibroblast degeneration during granular corneal dystrophy type 2 (GCD2) and melatonin is an effective antioxidant, we examined the ability of melatonin to protect against oxidative stress-induced cell death of primary cultured normal and GCD2-homozygous corneal fibroblasts. Melatonin treatment protected primary cultured normal and GCD2 corneal fibroblasts from paraquat (PQ)-induced oxidative stress and caused increased expression levels of Cu/Zn-superoxide dismutase (SOD1) and glutathione reductase (GR) in both types of cells. Interestingly, catalase expression increased in normal corneal fibroblasts, but decreased in GCD2 corneal fibroblasts after melatonin treatment. Melatonin also reduced the levels of intracellular reactive oxygen species and H(2)O(2) in both cell types. In addition, the selective melatonin receptor antagonist luzindole blocked melatonin-induced expression of SOD1 and GR. The expression levels of melatonin receptors 1A (MT1) and 1B (MT2) were significantly higher in GCD2 corneal fibroblasts than in normal cells. These results suggest that increased expression of melatonin receptors may be involved in the defense mechanisms against oxidative stress in GCD2 corneal fibroblasts, and melatonin may have potential therapeutic implications for GCD2 treatment.     

Cell-surface residence of sphingosine 1-phosphate receptor 1 on lymphocytes determines lymphocyte egress kinetics

The sphingosine 1-phosphate receptor 1 (S1P₁) promotes lymphocyte egress from lymphoid organs. Previous work showed that agonist-induced internalization of this G protein–coupled receptor correlates with inhibition of lymphocyte egress and results in lymphopenia. However, it is unclear if S1P₁ internalization is necessary for this effect. We characterize a knockin mouse (S1p1r^S5A/S5A) in which the C-terminal serine-rich S1P₁ motif, which is important for S1P₁ internalization but dispensable for S1P₁ signaling, is mutated. T cells expressing the mutant S1P₁ showed delayed S1P₁ internalization and defective desensitization after agonist stimulation. Mutant mice exhibited significantly delayed lymphopenia after S1P₁ agonist administration or disruption of the vascular S1P gradient. Adoptive transfer experiments demonstrated that mutant S1P₁ expression in lymphocytes, rather than endothelial cells, facilitated this delay in lymphopenia. Thus, cell-surface residency of S1P₁ on T cells is a primary determinant of lymphocyte egress kinetics in vivo.Sphingosine 1-phosphate (S1P), a multifunctional lipid mediator that signals via five G protein–coupled receptors (GPCRs), regulates vascular maturation, permeability, and angiogenesis (Hla, 2004; Cyster, 2005). Recently, interest in the roles of S1P and its receptors in the immune system has been prompted in part by the identification of the immunomodulator FTY720 (Brinkmann et al., 2002; Mandala et al., 2002; Chiba, 2005), which upon phosphorylation by Sphk2 to FTY720-P (Sanchez et al., 2003; Zemann et al., 2006) acts as a strong agonist for four out of five S1P receptors (Brinkmann et al., 2004). FTY720 induces profound lymphopenia by inhibiting the egress of lymphocytes from the thymus, peripheral lymph nodes, and Peyer’s patches (Chiba, 2005). Indeed, it is now appreciated that S1P signaling modulates the trafficking of not only naive and central memory T cells, but also B cells, dendritic cells, NK cells, osteoclasts, and hematopoietic progenitor cells (Allende and Proia, 2002; Kabashima et al., 2006; Massberg et al., 2007; Schwab and Cyster, 2007; Walzer et al., 2007; Ledgerwood et al., 2008; Rivera et al., 2008; Sebzda et al., 2008; Ishii et al., 2009). These studies suggest that S1P regulates hematopoietic and immune cell trafficking under homeostatic and disease conditions; however, it is unclear precisely how S1P receptor signaling modulates cellular responses to egress cues.The mechanism of how S1P regulates T cell trafficking has been intensively investigated; T cell–specific deletion of S1p1r or hematopoietic reconstitution using S1p1r^−/− fetal liver cells resulted in profound lymphopenia, suggesting that the T cell–intrinsic S1P receptor 1 (S1P₁) is essential for their egress from the thymus and secondary lymph nodes (Allende et al., 2004; Matloubian et al., 2004). This observation, coupled with the finding that FTY720-P induces the loss of cell-surface S1P₁ from lymphocytes in an irreversible manner (Gräler and Goetzl, 2004; Matloubian et al., 2004), suggests that functional antagonism of S1P₁ in the lymphocyte compartment is essential for the inhibition of T cell egress.However, other studies have led to the proposal of an alternative mechanism by which S1P₁ regulates lymphocyte egress. Immunofluorescence microscopy demonstrated high expression levels of S1P₁ in endothelial cells, whereas staining of lymphocytes was weaker (Singer et al., 2005; Sinha et al., 2009). Moreover, administration of SEW2971, a selective S1P₁ agonist, does not induce irreversible receptor loss from the cell surface but causes significant lymphopenia in vivo (Jo et al., 2005). Two-photon microscopy of explanted lymph nodes containing labeled lymphocytes suggested that S1P₁ agonists may modulate barrier function and closure of vascular portals in the medulla, through which T cells egress into efferent lymphatics (Wei et al., 2005). Thus, this alternative proposal favors endothelial cells as the primary target cell type for S1P₁ agonists to inhibit lymphocyte egress (Rosen et al., 2008).Close interactions between immune and vascular cells may underlie the ability of S1P₁ to promote lymphocyte egress. In lymph node cortical sinuses, egress of T and B cells required S1P₁-dependent transendothelial traverse (Grigorova et al., 2009; Sinha et al., 2009). Indeed, competing chemotactic signaling between the egress-promoting S1P–S1P₁ system and the retention-promoting CXCL21–CCR7 chemokine receptor system of T cells appears to determine the rate and extent of their egress from secondary lymphoid organs (Pham et al., 2008). Whether S1P₁ signaling in lymphocytes, endothelial compartments, or both is important in the process of egress is not known.S1P₁ is a type I GPCR that is rapidly phosphorylated upon agonist stimulation. Although several protein kinases are involved in the phosphorylation of S1P₁ (Lee et al., 2001), phosphorylation at the C-terminal domain is particularly relevant to receptor desensitization and internalization (Hla, 2001). Because FTY720-P is degraded less efficiently than S1P by S1P lyase and S1P phosphatases (Bandhuvula et al., 2005; Mechtcheriakova et al., 2007; Yamanaka et al., 2008), its ligation likely induces sustained receptor activation kinetics. Presumably, this underlies the FTY720-P–induced irreversible internalization and proteosomal degradation of S1P₁ and resultant lymphopenia (Oo et al., 2007). The GRK-2 enzyme is capable of phosphorylating the serine-rich motif in the C-terminal tail of S1P₁ (Watterson et al., 2002), and we recently demonstrated that mutation of the five serines in the C terminus of S1P₁ to nonphosphorylatable alanines inhibited S1P- and FTY720-P–induced receptor internalization in transfected HEK293 cells (Oo et al., 2007). Although previous studies of GPCR signaling and chemotaxis have provided some insights into the role of internalization in these processes, the results appear to be receptor specific. For example, a CXCR4 superagonist induced greater chemotaxis than the native ligand stromal cell–derived factor–1α (SDF-1α) with no perceptible receptor internalization (Sachpatzidis et al., 2003). Conversely, mutations in the C terminus of CXCR2 resulted in defective receptor internalization concomitant with impaired chemotaxis (Sachpatzidis et al., 2003). In the case of S1P₁, it is unknown whether internalization is required for lymphocyte egress and recirculation.To address the role of S1P₁ internalization in the control of lymphocyte egress during homeostasis and FTY720 treatment, we developed a mouse model in which WT S1P₁ is replaced by the internalization-deficient mutant (S5A-S1P₁). We show that although T cell trafficking under homeostasis is unaltered, S1p1r^S5A/S5A mice display kinetic resistance to lymphopenia induced by the S1P₁ modulator (FTY720-P) or disruption of the S1P gradient. Adoptive transfer of S1p1r^WT/WT and S1p1r^S5A/S5A lymphocytes and S1P₁ surface staining of lymph node endothelial cells demonstrate that the T cell S1P₁, and not endothelial cell S1P₁ expression, regulates the rate of lymphocyte egress in vivo. These data support a T cell–intrinsic model of S1P₁ signaling in egress kinetics wherein the internalization of S1P₁ is a crucial modulator of the cues for T cell migration.     

Incidental Colonic 18F-Fluorodeoxyglucose Uptake: Do We Need Colonoscopy for Patients with Focal Uptake Confined to the Left-Sided Colon?

Background/Aims

Although access to [¹⁸F]2-fluoro-2-deoxyglucose (¹⁸F-FDG) positron emission tomography and computed axial tomography (PET/CT) for patients with malignancy has increased, little information is available on the suitability of PET/CT for diagnosis of advanced colonic neoplasms in oncology patients and on the clinical significance of incidental ¹⁸F-FDG focal uptake confined to the left-sided colon.

Methods

Patients who underwent ¹⁸F-FDG PET/CT followed, within 90 days, by colonoscopy were identified. Case–control analysis was undertaken to determine whether focal ¹⁸F-FDG uptake confined to the left-sided colon was associated with advanced neoplasms in the right-sided colon.

Results

One hundred ninety-five patients with colonic ¹⁸F-FDG uptake and 561 without colonic ¹⁸F-FDG uptake were identified. Of the 195 patients with focal colonic ¹⁸F-FDG activity, 103 patients (52.8 %) had 145 advanced colonic neoplasms, including 58 colon cancers and 11 metastatic cancers. In the detection of advanced colonic neoplasms, the sensitivity, specificity, positive predictive value, and negative predictive value of PET/CT were 54.4, 82.4, 46.9, and 86.3 %, respectively. Overall accuracy was 76.2 %. Ten (8.0 %) of the 125 patients with focal ¹⁸F-FDG uptake confined to the left-sided colon had three colon cancers and seven advanced adenomas in the right-sided colon. Case–control analysis revealed that focal ¹⁸F-FDG uptake confined to the left-sided colon was associated with an advanced neoplasms in the right-sided colon (OR, 3.02; 95 % CI, 1.12–8.13; P = 0.023).

Conclusions

Colonic focal ¹⁸F-FDG uptake by oncology patients warrants endoscopic verification. Complete colon evaluation by colonoscopy is required, even for patients with focal ¹⁸F-FDG uptake confined to the left-sided colon.     

Long-term outcome in patients with obscure gastrointestinal bleeding after negative capsule endoscopy

AIM:To investigate long-term outcome in obscure gastrointestinal bleeding(OGIB) after negative capsule endoscopy(CE) and identify risk factors for rebleeding.METHODS:A total of 113 consecutive patients underwent CE for OGIB from May 2003 to June 2010 at Seoul National University Hospital.Ninety-five patients(84.1%) with a subsequent follow-up after CE of at least 6 mo were enrolled in this study.Follow-up data were obtained from the patients’ medical records.The CE images were reviewed by two board-certified gastroenterologists and consensus diagnosis was used in all cases.The primary outcome measure was the detection of rebleeding after CE,and factors associated with rebleeding were evaluated using multivariate analysis.RESULTS:Of the 95 enrolled patients(median age 61 years,range 17-85 years),62 patients(65.3%) were male.The median duration of follow-up was 23.7 mo(range 6.0-89.4 mo).Seventy-three patients(76.8%) underwent CE for obscure-overt bleeding.Complete examination of the small bowel was achieved in 77 cases(81.1%).Significant lesions were found in 38 patients(40.0%).The overall rebleeding rate was 28.4%.The rebleeding rate was higher in patients with positive CE(36.8%) than in those with negative CE(22.8%).However,there was no significant difference in cumulative rebleeding rates between the two groups(log rank test;P = 0.205).Anticoagulation after CE examination was an independent risk factor for rebleeding(hazard ratio,5.019;95%CI,1.560-16.145;P = 0.007),regardless of CE results.CONCLUSION:Patients with OGIB and negative CE have a potential risk of rebleeding.Therefore,close observation is required and alternative modalities should be considered in suspicious cases.     

Under‐recognized soft‐tissue structures inferior and lateral to the head of the clavicle: Anatomy with computed tomography correlation

This study was undertaken to provide an anatomical explanation for two soft‐tissue structures anecdotally found on axial computed tomography (CT) scan, which are inferior (SI) and lateral (SL) to the head of the clavicle and adjacent to the sternoclavicular joint (SCJ). Three sets of cryosection images were reviewed to identify the anatomical structures corresponding to SI and SL. To demonstrate that SI and/or SL communicate with the SCJ cavity in the living, 312 consecutive chest CT scans were assessed for coexistence of SCJ and SI/SL air. To prove that under‐recognition of SI and SL is due to the use of thick‐section CT scan, another 50 consecutive chest CT scans were evaluated: visibility of SI and SL, and continuity between them on thick (5 mm)‐section images were compared with those on thin (0.75 mm)‐section images. The anterior portions of SI and SL were extensions from the SCJ cavity in the cryosection images, with the articular cartilage and disc occupying variable volumes of SI. The posterior portions of the SI and SL corresponded to the thyroid strap muscles. Air was present in 1 SI, 6 SLs, and 10 SCJs. Four of five patients with SI or SL air had coexisting SCJ air. Thick sections provided significantly poor visibility of SI and SL and continuity compared with thin‐section images. SI and SL are constant shadows on thin‐section CT scan, and their anterior and posterior portions represent extensions of the SCJ cavity and the strap muscles, respectively. The use of thick sections may be responsible for the under‐recognition of SI and SL on CT scan. Clin. Anat. 23:803–810, 2010. © 2010 Wiley‐Liss, Inc.