Carlos Cuevas

Enzymatic Targeting of the Stroma Ablates Physical Barriers to Treatment of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinomas (PDAs) are characterized by a robust fibroinflammatory response. We show here that this desmoplastic reaction generates inordinately high interstitial fluid pressures (IFPs), exceeding those previously measured or theorized for solid tumors, and induces vascular collapse, while presenting substantial barriers to perfusion, diffusion, and convection of small molecule therapeutics. We identify hyaluronan, or hyaluronic acid (HA), as the primary matrix determinant of these barriers and show that systemic administration of an enzymatic agent can ablate stromal HA from autochthonous murine PDA, normalize IFP, and re-expand the microvasculature. In combination with the standard chemotherapeutic, gemcitabine, the treatment permanently remodels the tumor microenvironment and consistently achieves objective tumor responses, resulting in a near doubling of overall survival.

High-Intensity Focused Ultrasound : Current Potential and Oncologic Applications

OBJECTIVE The objective of this article is to introduce the reader to the principles and applications of high-intensity focused ultrasound (HIFU). CONCLUSION Although a great deal about HIFU physics is understood, its clinical applications are currently limited, and multiple trials are underway worldwide to determine its efficacy.

Imaging of Uncommon Retroperitoneal Masses

Retroperitoneal masses not arising from major solid organs are uncommon. Although there is no simple method of classifying retroperitoneal masses, a reasonable approach is to consider the masses as predominantly solid or cystic and to subdivide these into neoplastic and nonneoplastic masses. Because the treatment options vary, it is useful to be able to differentiate these masses by using imaging criteria. Although the differential diagnosis of retroperitoneal masses can be narrowed down to a certain extent on the basis of imaging characteristics, patterns of involvement, and demographics, there is still a considerable overlap of imaging findings for these masses, and histologic examination is often required for definitive diagnosis. Computed tomography (CT) and magnetic resonance (MR) imaging play an important role in characterization and in the assessment of the extent of the disease and involvement of adjacent and distant structures. Familiarity with the CT and MR imaging features of various retroperitoneal masses will facilitate accurate diagnosis and staging for aggressive lesions.

Targeted depletion of an MDSC subset unmasks pancreatic ductal adenocarcinoma to adaptive immunity

Background Pancreatic ductal adenocarcinoma (PDA) is characterised by a robust desmoplasia, including the notable accumulation of immunosuppressive cells that shield neoplastic cells from immune detection. Immune evasion may be further enhanced if the malignant cells fail to express high levels of antigens that are sufficiently immunogenic to engender an effector T cell response. Objective To investigate the predominant subsets of immunosuppressive cancer-conditioned myeloid cells that chronicle and shape the progression of pancreas cancer. We show that selective depletion of one subset of myeloid-derived suppressor cells (MDSC) in an autochthonous, genetically engineered mouse model (GEMM) of PDA unmasks the ability of the adaptive immune response to engage and target tumour epithelial cells. Methods A combination of in vivo and in vitro studies were performed employing a GEMM that faithfully recapitulates the cardinal features of human PDA. The predominant cancer-conditioned myeloid cell subpopulation was specifically targeted in vivo and the biological outcomes determined. Results PDA orchestrates the induction of distinct subsets of cancer-associated myeloid cells through the production of factors known to influence myelopoiesis. These immature myeloid cells inhibit the proliferation and induce apoptosis of activated T cells. Targeted depletion of granulocytic MDSC (Gr-MDSC) in autochthonous PDA increases the intratumoral accumulation of activated CD8 T cells and apoptosis of tumour epithelial cells and also remodels the tumour stroma. Conclusions Neoplastic ductal cells of the pancreas induce distinct myeloid cell subsets that promote tumour cell survival and accumulation. Targeted depletion of a single myeloid subset, the Gr-MDSC, can unmask an endogenous T cell response, disclosing an unexpected latent immunity and invoking targeting of Gr-MDSC as a potential strategy to exploit for treating this highly lethal disease.

Risk factors for recurrence of primary sclerosing cholangitis after liver transplantation

Orthotopic liver transplantation (OLT) is the only effective treatment for end‐stage liver disease due to primary sclerosing cholangitis (PSC). Recurrence of PSC has recently emerged as a leading cause of allograft failure in the long term. There is limited data on risk factors for recurrence of PSC. We performed a retrospective analysis of 69 consecutive patients who underwent a first OLT for PSC over a 14‐year period. Baseline characteristics and clinical and laboratory test results post‐LT were recorded. Cholangiograms and liver histopathology were reviewed in a blinded manner by an experienced radiologist and hepatopathologist. Recurrent PSC was diagnosed using previously published Mayo Clinic cholangiographic or histologic criteria. Of 69 patients, 7 (10%) developed recurrent PSC at a median of 68 months (range, 24‐134 months) post‐LT. The following variables were associated with recurrent PSC in our cohort: presence of human leukocyte antigen (HLA)‐DRB1*08 (29% versus 2%; P= 0.026; odds ratio [OR], 24.4; 95% confidence interval [CI], 1.8‐318.1), acute cellular rejection (ACR) (71% versus 22%; P= 0.015; OR, 8.7; 95% CI, 1.5‐49.9), and steroid‐resistant ACR (29% versus 0%; P= 0.012). Despite the strong linkage disequilibrium between DRB1*08 and DQB1*04, DRB1*08‐positive subjects with recurrence were negative for DQB1*04, whereas the single DRB1*08‐positive subject without recurrent PSC was positive for DQB1*04. A history of ACR and presence of HLA‐DRB1*08 are associated with increased risk of recurrent PSC, suggesting an immunologic mechanism for this syndrome. Further studies are required to confirm these observations and to understand the underlying mechanisms. Liver Transpl 14:245–251. 2008.

T Cells Engineered against a Native Antigen Can Surmount Immunologic and Physical Barriers to Treat Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinomas (PDAs) erect physical barriers to chemotherapy and induce multiple mechanisms of immune suppression, creating a sanctuary for unimpeded growth. We tested the ability of T cells engineered to express an affinity-enhanced T cell receptor (TCR) against a native antigen to overcome these barriers in a genetically engineered model of autochthonous PDA. Engineered T cells preferentially accumulate in PDA and induce tumor cell death and stromal remodeling. However, tumor-infiltrating T cells become progressively dysfunctional, a limitation successfully overcome by serial T cell infusions that resulted in a near-doubling of survival without overt toxicities. Similarly engineered human T cells lyse PDA cells in vitro, further supporting clinical advancement of this TCR-based strategy for the treatment of PDA.

Ultrasound-Based Elastography: A Novel Approach to Assess Radio Frequency Ablation of Liver Masses Performed With Expandable Ablation Probes A Feasibility Study

Objective. The purpose of this study was to evaluate the technical feasibility of ultrasound‐based elastography as a tool for assessing the size and shape of the coagulation necrosis caused by radio frequency ablation (RFA) probes using expandable electrodes ex vivo as well as in a patient with a liver metastasis. Methods. A commercially available expandable RFA probe was used to create a 3‐cm ablation in a piece of bovine liver. The ablation probe was used in situ to induce tissue deformation for elastography before and after ablation. Ultrasonic radio frequency data were processed to generate elasticity strain images. The appearance of the ablation zone was compared with magnetic resonance imaging and a gross section specimen. One patient with malignant metastatic disease to the liver and a clinical indication for RFA was investigated for the feasibility of percutaneous elastography of RFA using the same technique. Sonographic strain images were compared with the appearance of the nonenhancing ablation zone on contrast‐enhanced computed tomography. Results. Ex vivo, the ablation zone on ultrasound‐based elastography was represented by an area of increased stiffness and was well demarcated from the nonablated surrounding tissue. The size and shape of the ablated zone on the strain image correlated well with the gross specimen and the magnetic resonance imaging appearance. Strain images obtained from the patient showed results similar to those of the ex vivo experiment and correlated well with the nonenhancing area of ablation on contrast‐enhanced computed tomography. Conclusions. Ultrasound‐based elastography may be a promising tool for displaying the ablation zone created by expandable RFA probes.

Imaging Techniques for the Diagnosis of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis.

Hepatocellular carcinoma (HCC) is the most common primary malignant neoplasm of the liver, usually developing in persons with chronic liver disease. Worldwide, it is the fifth most common type of cancer and the third most common cause of death from cancer (1). There were 25000 deaths attributed to liver and intrahepatic bile duct cancer in the United States in 2011 (2). Common causes of HCC are hepatitis C virus infection, hepatitis B virus infection, and alcohol abuse, although a substantial proportion of cases have no identifiable cause (35). Imaging modalities for HCC include ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). Although CT and MRI provide higher-resolution images than ultrasonography, they are also more costly and, in the case of CT, are associated with radiation exposure (5). Because HCC is typically a hypervascular lesion, CT and MRI are performed with arterial-enhancing contrast agents. Microbubble-enhanced ultrasonography can also be performed, although agents are not yet approved by the U.S. Food and Drug Administration for this purpose, and microbubbles are present in the liver for only a limited duration (6). Other technical, patient, and tumor factors may also affect test performance (712). This article reviews the test performance of ultrasonography, MRI, and CT for detection of HCC and for evaluation of focal liver lesions. This was conducted as part of a larger review commissioned by the Agency for Healthcare Research and Quality (AHRQ) on HCC imaging (13). Supplement. Original Version (PDF) Methods Scope of the Review The protocol was developed by using a standardized process with input from experts and the public and was registered in the PROSPERO database (CRD42014007016) (14). The review protocol included key questions on the comparative test performance of imaging for detection of HCC and for evaluation of focal liver lesions. Detailed methods and data for the review, including search strategies, inclusion criteria, and abstraction and quality ratings tables, are available in the full report, which also includes further key questions, full sensitivity and subgroup analyses, and an additional imaging modality (positron emission tomography) (13). Data Sources and Searches A research librarian searched multiple electronic databases, including MEDLINE (1998 to December 2013 for the full report; the update search for the review in this article was performed in December 2014), the Cochrane Library, and Scopus. Additional studies were identified by reviewing reference lists and from peer review suggestions. Study Selection Two investigators independently evaluated each study at the title/abstract and full-text article stages to determine inclusion eligibility (Appendix Table 1). We included studies on the test performance of ultrasonography, CT, or MRI against a reference standard for detection of HCC in surveillance or nonsurveillance settings (for example, imaging performed in patients undergoing treatment for liver disease or in whom HCC was previously diagnosed) or for further evaluation of focal liver lesions. Reference standards were histopathologic examination based on explanted liver or nonexplant histologic specimens, imaging plus clinical follow-up (for example, lesion growth), or a combination of these. Appendix Table 1. Inclusion and Exclusion Criteria We selected studies of ultrasonography (with or without contrast) and contrast-enhanced CT and MRI that met minimum technical criteria (non-multidetector or multidetector spiral CT, or 1.5- or 3.0-T MRI) (7). We excluded studies published before 1998 and those in which imaging began before 1995, unless the imaging methods met minimum technical criteria; studies of MRI with contrast agents no longer commercially produced (for example, superparamagnetic iron oxide [ferumoxides or ferucarbotran] or mangafodipir); and studies of CT arterial portography, CT hepatic angiography, and intraoperative ultrasonography. We included studies of ultrasonography microbubble contrast agents because they are commercially available and commonly used outside the United States, and efforts to obtain approval from the U.S. Food and Drug Administration are ongoing (1517). We excluded studies of diagnostic accuracy for non-HCC malignant lesions, including liver metastases. We included studies that reported results for HCC and cholangiocarcinoma together if cholangiocarcinoma lesions comprised less than 10% of the total. Studies on the accuracy of imaging for distinguishing HCC from a specific type of liver lesion (such as hemangioma or pseudolesion) and on the accuracy of imaging tests used in combination are addressed in the full report (13). We excluded studies published only as conference abstracts and included only English-language articles. The literature flow diagram is shown in Appendix Figure 1. Appendix Figure 1. Summary of evidence search and selection. * Studies of positron emission tomography; effects on clinical decisions, clinical outcomes, or staging; and accuracy for distinguishing hepatocellular carcinoma lesions from another specific type of liver lesion are addressed in the full report (13). Data Abstraction and Quality Rating One investigator abstracted details on the study design, dates of imaging and publication, patient population, country, sample size, imaging method and associated technical factors (Appendix Table 2), and results. Two investigators independently applied the approach recommended in the AHRQ Methods Guide for Medical Test Reviews to assess risk of bias as high, moderate, or low (18, 19). Appendix Table 2. Technical Factors Abstracted, by Imaging Modality Data Synthesis We conducted meta-analysis with a bivariate logistic mixed random-effects model that incorporated the correlation between sensitivity and specificity, using SAS software, version 9.3 (SAS Institute) (20). We assumed bivariate normal distributions for sensitivity and specificity. Statistical heterogeneity was measured with the random-effect variance (2). We calculated positive and negative likelihood ratios by using the summarized sensitivity and specificity (21, 22). We analyzed data separately for each imaging modality; ultrasonography with and without contrast were also analyzed separately. We also separately analyzed studies in which imaging was performed for detection of HCC and for evaluation of focal liver lesions; studies on HCC detection were further stratified by setting (surveillance or nonsurveillance). We separately analyzed test performance by using patients with HCC or by using HCC lesions (one patient can have multiple lesions) as the unit of analysis. Other sensitivity and subgroup analyses were conducted on the reference standard, factors related to risk of bias, country, technical factors (Appendix Table 2), tumor factors (such as HCC lesion size or degree of tumor differentiation), and patient characteristics (for example, severity of underlying liver disease, underlying cause of liver disease, and body mass index). We performed separate analyses on the subset of studies that directly compared 2 or more imaging modalities or techniques in the same population against a common reference standard (23). We used the same bivariate logistic mixed-effects model as described above, with an added indicator variable for imaging modalities. We also performed meta-analyses for within-study comparisons on lesion size, degree of tumor differentiation, and (when data were available) technical factors. We graded the strength of each body of evidence as high, moderate, low, or insufficient on the basis of the aggregate risk of bias, consistency, precision, and directness (24). Role of the Funding Source This research was funded by the AHRQ Effective Health Care Program. Investigators worked with AHRQ staff to develop and refine the review protocol. The AHRQ staff had no role in conducting the review, and the investigators are solely responsible for the content of the manuscript and the decision to submit for publication. Results Of the 5202 citations identified at the title and abstract level, 890 articles seemed to meet inclusion criteria and were selected for further full-text review. After full-text review, 241 studies (Appendix Table 3) met inclusion criteria for the key questions and imaging modalities addressed in this review (Appendix Figure 1). Appendix Table 3. References to Articles That Met the Inclusion Criteria Appendix Table 3Continued. Appendix Table 3Continued. Sixty-eight studies evaluated ultrasonography (Appendix Table 3), 131 evaluated CT (25153), and 125 evaluated MRI (Appendix Table 3). Almost all studies reported sensitivity, but specificity was available in only 139 studies. We rated 5 studies as having low risk of bias (56, 99, 128, 132, 154), 199 as having moderate risk of bias, and 89 as having high risk of bias (13). One hundred twenty-five studies avoided use of a casecontrol design, 160 used blinded design, and 75 were prospective. More studies were conducted in Asia (190 studies) than in Australia, Canada, the United States, or Europe (95 studies in total for these regions). In 166 studies, imaging began in or after 2003 (13). Twenty-eight studies evaluated CT using methods that met minimum technical specifications (8-row multidetector CT; contrast rate 3 mL/s; at least arterial, portal venous, and delayed-phase imaging; delayed-phase imaging performed >120 s after administration of contrast; and enhanced imaging section thickness 5 mm), and 67 studies evaluated MRI using methods that met minimum technical specifications (1.5- or 3.0-T MRI; at least arterial, portal venous, and delayed-phase imaging; delayed-phase imaging performed >120 s after administration of contrast; and enhanced imaging section thickness 5 mm). Seventy-three MRI studies evaluated use of hepatic-specific contrast (for example, gadoxetic acid or gadobenate). Forty-seven ultrasonography studies evaluated use of

Sonography in first trimester bleeding

Vaginal bleeding is the most common cause of presentation to the emergency department in the first trimester. Approximately half of patients with first trimester vaginal bleeding will lose the pregnancy. Clinical assessment is difficult, and sonography is necessary to determine if a normal fetus is present and alive and to exclude other causes of bleeding (eg, ectopic or molar pregnancy). Diagnosis of a normal intrauterine pregnancy not only helps the physician in terms of management but also gives psychologic relief to the patient. Improved ultrasound technology and high‐frequency endovaginal transducers have enabled early diagnosis of abnormal and ectopic pregnancies, decreasing maternal morbidity and mortality. The main differential considerations of first trimester bleeding are spontaneous abortion, ectopic pregnancy, or gestational trophoblastic disease. This article reviews the causes of first trimester bleeding and the sonographic findings, including normal features of first trimester pregnancy.

Glutathione transferase mu 2 protects glioblastoma cells against aminochrome toxicity by preventing autophagy and lysosome dysfunction

U373MG cells constitutively express glutathione S-transferase mu 2 (GSTM2) and exhibit 3H-dopamine uptake, which is inhibited by 2 µM of nomifensine and 15 µM of estradiol. We generated a stable cell line (U373MGsiGST6) expressing an siRNA against GSTM2 that resulted in low GSTM2 expression (26% of wild-type U373MG cells). A significant increase in cell death was observed when U373MGsiGST6 cells were incubated with 50 µM purified aminochrome (18-fold increase) compared with wild-type cells. The incubation of U373MGsiGST6 cells with 75 µM aminochrome resulted in the formation of autophagic vacuoles containing undigested cellular components, as determined using transmission electron microscopy. A significant increase in autophagosomes was determined by measuring endogenous LC3-II, a significant decrease in cell death was observed in the presence of bafilomycin A1, and a significant increase in cell death was observed in the presence of trehalose. A significant increase in LAMP2 immunostaining was observed, a significant decrease in bright red fluorescence of lysosomes with acridine orange was observed, and bafilomycin A1 pretreatment reduced the loss of lysosome acidity. A significant increase in cell death was observed in the presence of lysosomal protease inhibitors. Aggregation of TUBA/α-tubulin (tubulin, α) and SQSTM1 protein accumulation were also observed. Moreover, a significant increase in the number of lipids droplets was observed compared with U373MG cells with normal expression of GSTM2. These results support the notion that GSTM2 is a protective enzyme against aminochrome toxicity in astrocytes and that aminochrome cell death in U373MGsiGST6 cells involves autophagic-lysosomal dysfunction.