Citations

ABSTRACT Dynamin is a 100‐kDa GTPase that has been implicated in endocytosis. To extend our understanding of its cellular functions, we have microinjected specific affinity‐purified anti‐dynamin antibodies into cultured mammalian epithelial cells. Using this approach, dynamin function can be inhibited specifically and rapidly in single cells. Effects of microinjected inhibitory antibodies on distinct endocytic processes and plasmalemmal morphology were then assayed by fluorescence microscopy (FM) and ultrastructural analysis. Microinjected antibodies inhibit the clathrin‐mediated endocytosis of fluorophore‐labeled transferrin and cause a marked invagination of the plasma membrane. Many of these long plasmalemmal invaginations had clathrin‐coated pits along their cytoplasmic surface. A number of distinct noncoated pits resembling plasmalemmal caveolae also accumulated in anti‐dynamin antibody‐injected cells. Further, the cellular uptake of cholera toxin B, which normally occurs by the internalization of caveolae, was inhibited in these cells. In support of these observations, immunoisolation techniques, double‐label immuno‐FM, and immunoelectron microscopy (immuno‐EM) provided biochemical and morphological evidence that dynamin associates with plasmalemmal caveolae. Together, these observations indicate that dynamin mediates scission from the plasma membrane of both clathrincoated pits and caveolae during distinct endocytic processes. These results demonstrate that dynamin isoforms are involved in an additional endocytic process that is distinct from clathrinmediated endocytosis and provide significant insights into the molecular mechanisms governing the GTP‐mediated internalization of caveolae. Evidence is provided demonstrating that dynamin isoforms have a differential distribution in mammalian cells. Targeting information for these isoforms is provided at least in part by regions of alternative splicing. Thus, the different dynamin isoforms may be localized to distinct cellular compartments but provide a similar scission function during the biogenesis of nascent cytoplasmic vesicles—Henley, J. R., Cao, H., McNiven, M. A. Participation of dynamin in the biogenesis of cytoplasmic vesicles. FASEB J. 13 (Suppl.), S243‐S247 (1999)

Objective: To determine the impact of histology on pathologic response, survival outcomes, and recurrence patterns in patients with esophageal cancer (EC) who received neoadjuvant chemoradiotherapy (CRT). Summary of Background Data: There is a paucity of data regarding comparative outcomes after neoadjuvant CRT between esophageal squamous cell carcinoma (SCC) and adenocarcinoma. Methods: Between 2002 and 2015, 895 EC patients who underwent neoadjuvant CRT followed by esophagectomy at 3 academic institutions were retrospectively reviewed, including 207 patients with SCC (23.1%) and 688 patients with adenocarcinoma (76.9%). Pathologic response, survival, recurrence pattern, and potential prognostic factors were compared. Results: Pathologic complete response (pCR) rate was significantly higher for SCC compared with adenocarcinoma (44.9% vs 25.9%, P < 0.001). After a median follow-up of 52.9 months, 71 patients (34.3%) with SCC versus 297 patients (43.2%) with adenocarcinoma had recurrent disease (P = 0.023). For patients who achieved a pCR, no significant differences were found in recurrence pattern, sites, or survival end-points between the 2 histology groups. For non-pCR patients, the SCC group demonstrated significantly higher regional and supraclavicular recurrence rates but a lower hematogenous metastasis rate than adenocarcinoma patients, whereas the adenocarcinoma patients had a more favorable locoregional failure-free survival (P = 0.005) and worse distant metastasis-free survival (P = 0.024). No differences were found in overall survival (P = 0.772) or recurrence-free survival (P = 0.696) between groups. Conclusions: SCC was associated with a significantly higher pCR rate than adenocarcinoma. Recurrence pattern and survival outcomes were significantly different between the 2 histology subtypes in non-pCR patients.

Background Intracranial aneurysms represent a significant health concern and are poorly understood despite decades of research. Our study focused on understanding temporal patterns of endothelial cell distribution in different spatial locations within the aneurysm early after creation in a rabbit model. Methods Elastase induced saccular aneurysms were created in rabbits and harvested on day 1 (n=3) and after 2 (n=5), 4 (n=4), 8 (n=5), and 12 (n=6) weeks. Sham operated controls (n=3) were harvested on the same day. Aneurysm and control tissue samples were subjected to en face whole mount CD31 staining for endothelial cells. Semiquantitative scoring was performed on the basis of endothelial coverage of the vessel wall (proximal, middle, and distal portions of the aneurysm dome). Mixed effects models were used to assess the effect of time and aneurysm section on endothelial coverage. Results Aneurysmal segments were near completely de-endothelialized at 4 and 8 weeks but had re-endothelialized by 12 weeks. Compared with controls, aneurysms at all time points showed decreased endothelialization, but the difference was only significant compared with the 4 and 8 week groups. Both time (P=0.03) and aneurysm section (P=0.07) were significantly associated with the degree of endothelialization. Proximal locations showed increased endothelialization compared with distal locations (P=0.03). Conclusion In experimental aneurysms of rabbits, endothelial cells regress during the first month after creation, followed by ascending re-endothelialization that stays incomplete. These findings suggest that re-population of endothelial cells comes from resident cells in the adjacent parent artery and that deranged hemodynamics may affect full reconstitution of endothelial cells long term.

ABSTRACT There is a clinical need to identify new molecular targets for the treatment of osteoporosis, particularly those that simultaneously inhibit bone resorption while stimulating bone formation. We have previously shown in overexpression studies that retinoic acid receptor-related orphan receptor β (Rorβ) suppresses in vitro osteoblast differentiation. In addition, the expression of Rorβ is markedly increased in bone marrow–derived mesenchymal stromal cells with aging in both mice and humans. Here we establish a critical role for Rorβ in regulating bone metabolism using a combination of in vitro and in vivo studies. We used Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 gene editing to demonstrate that loss of Rorβ in osteoblasts enhances Wnt signaling, specifically through increased recruitment of β-catenin to T-cell factor/lymphoid enhancer factor (Tcf/Lef) DNA binding sites in the promoters of the Wnt target genes Tcf7 and Opg. This resulted in increased osteogenic gene expression and suppressed osteoclast formation through increased osteoprotegerin (OPG) secretion in Rorβ-deficient cells. Consistent with our in vitro data, genetic deletion of Rorβ in both female and male mice resulted in preserved bone mass and microarchitecture with advancing age due to increased bone formation with a concomitant decrease in resorption. The improved skeletal phenotype in the Rorβ–/– mice was also associated with increased bone protein levels of TCF7 and OPG. These data demonstrate that loss of Rorβ has beneficial skeletal effects by increasing bone formation and decreasing bone resorption, at least in part through β-catenin–dependent activation of the Wnt pathway. Thus, inhibition of Rorβ represents a novel approach to potentially prevent or reverse osteoporosis. © 2017 American Society for Bone and Mineral Research.

SummaryDue to the introduction of newer, more efficacious treatment options, there is a pressing need for policy makers and public health officials to develop or adapt national hepatitis C virus (HCV) control strategies to the changing epidemiological landscape. To do so, detailed, country‐specific data are needed to characterize the burden of chronic HCV infection. In this study of 17 countries, a literature review of published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates was conducted, and inputs were validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Hong Kong to 2.4% in Taiwan, while the largest viraemic populations were in Nigeria (2 597 000 cases) and Taiwan (569 000 cases). Diagnosis, treatment and liver transplant rates varied widely across the countries included in this analysis, as did the availability of reliable data. Addressing data gaps will be critical for the development of future strategies to manage and minimize the disease burden of hepatitis C.

SummaryFactors influencing the morbidity and mortality associated with viremic hepatitis C virus (HCV) infection change over time and place, making it difficult to compare reported estimates. Models were developed for 17 countries (Bahrain, Bulgaria, Cameroon, Colombia, Croatia, Dominican Republic, Ethiopia, Ghana, Hong Kong, Jordan, Kazakhstan, Malaysia, Morocco, Nigeria, Qatar and Taiwan) to quantify and characterize the viremic population as well as forecast the changes in the infected population and the corresponding disease burden from 2015 to 2030. Model inputs were agreed upon through expert consensus, and a standardized methodology was followed to allow for comparison across countries. The viremic prevalence is expected to remain constant or decline in all but four countries (Ethiopia, Ghana, Jordan and Oman); however, HCV‐related morbidity and mortality will increase in all countries except Qatar and Taiwan. In Qatar, the high‐treatment rate will contribute to a reduction in total cases and HCV‐related morbidity by 2030. In the remaining countries, however, the current treatment paradigm will be insufficient to achieve large reductions in HCV‐related morbidity and mortality.

SummaryThe hepatitis C virus (HCV) epidemic was forecasted through 2030 for 17 countries in Africa, Asia, Europe, Latin America and the Middle East, and interventions for achieving the Global Health Sector Strategy on viral hepatitis targets—“WHO Targets” (65% reduction in HCV‐related deaths, 90% reduction in new infections and 90% of infections diagnosed by 2030) were considered. Scaling up treatment and diagnosis rates over time would be required to achieve these targets in all but one country, even with the introduction of high SVR therapies. The scenarios developed to achieve the WHO Targets in all countries studied assumed the implementation of national policies to prevent new infections and to diagnose current infections through screening.

Abstract In some cases, laparoscopic cholecystectomy (LC) may be difficult to perform in patients with acute cholecystitis (AC) with severe inflammation and fibrosis. The Tokyo Guidelines 2018 (TG18) expand the indications for LC under difficult conditions for each level of severity of AC. As a result of expanding the indications for LC to treat AC, it is absolutely necessary to avoid any increase in bile duct injury (BDI), particularly vasculo‐biliary injury (VBI), which is known to occur at a certain rate in LC. Since the Tokyo Guidelines 2013 (TG13), an attempt has been made to assess intraoperative findings as objective indicators of surgical difficulty; based on expert consensus on these difficulty indicators, bail‐out procedures (including conversion to open cholecystectomy) have been indicated for cases in which LC for AC is difficult to perform. A bail‐out procedure should be chosen if, when the Calot's triangle is appropriately retracted and used as a landmark, a critical view of safety (CVS) cannot be achieved because of the presence of nondissectable scarring or severe fibrosis. We propose standardized safe steps for LC to treat AC. To achieve a CVS, it is vital to dissect at a location above (on the ventral side of) the imaginary line connecting the base of the left medial section (Segment 4) and the roof of Rouvière's sulcus and to fulfill the three criteria of CVS before dividing any structures. Achieving a CVS prevents the misidentification of the cystic duct and the common bile duct, which are most commonly confused. Free full articles and mobile app of TG18 are available at: http://www.jshbps.jp/modules/en/index.php?content_id=47 . Related clinical questions and references are also included.