50 research outputs found
The formation of vault-tubes: a dynamic interaction between vaults and vault PARP
Vaults are barrel-shaped cytoplasmic ribonucleoprotein particles that are
composed of a major vault protein (MVP), two minor vault proteins
[telomerase-associated protein 1 (TEP1), vault poly(ADP-ribose) polymerase
(VPARP)] and small untranslated RNA molecules. Not all expressed TEP1 and
VPARP in cells is bound to vaults. TEP1 is known to associate with the
telomerase complex, whereas VPARP is also present in the nuclear matrix
and in cytoplasmic clusters (VPARP-rods). We examined the subcellular
localization and the dynamics of the vault complex in a non-small cell
lung cancer cell line expressing MVP tagged with green fluorescent
protein. Using quantitative fluorescence recovery after photobleaching
(FRAP) it was shown that vaults move temperature independently by
diffusion. However, incubation at room temperature (21 degrees C) resulted
in the formation of distinct tube-like structures in the cytoplasm.
Raising the temperature could reverse this process. When the vault-tubes
were formed, there were fewer or no VPARP-rods present in the cytoplasm,
suggesting an incorporation of the VPARP into the vault-tubes. MVP
molecules have to interact with each other via their coiled-coil domain in
order to form vault-tubes. Furthermore, the stability of microtubules
influenced the efficiency of vault-tube formation at 21 degrees C. The
dynamics and structure of the tubes were examined using confocal
microscopy. Our data indicate a direct and dynamic relationship between
vaults and VPARP, providing further clues to unravel the function of
vaults
Disruption of the murine major vault protein (MVP/LRP) gene does not induce hypersensitivity to cytostatics
Vaults are ribonucleoprotein particles with a distinct structure and a
high degree of conservation between species. Although no function has been
assigned to the complex yet, there is some evidence for a role of vaults
in multidrug resistance. To confirm a direct relation between vaults and
multidrug resistance, and to investigate other possible functions of
vaults, we have generated a major vault protein (MVP/lung
resistance-related protein) knockout mouse model. The MVP(-/-) mice are
viable, healthy, and show no obvious abnormalities. We investigated the
sensitivity of MVP(-/-) embryonic stem cells and bone marrow cells derived
from the MVP-deficient mice to various cytostatic agents with different
mechanisms of action. Neither the MVP(-/-) embryonic stem cells nor the
MVP(-/-) bone marrow cells showed an increased sensitivity to any of the
drugs examined, as compared with wild-type cells. Furthermore, the
activities of the ABC-transporters P-glycoprotein, multidrug
resistance-associated protein and breast cancer resistance protein were
unaltered on MVP deletion in these cells. In addition, MVP wild-type and
deficient mice were treated with the anthracycline doxorubicin. Both
groups of mice responded similarly to the doxorubicin treatment. Our
results suggest that MVP/vaults are not directly involved in the
resistance to cytostatic agents
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Ultrafast dissolution and creation of bonds in IrTe2 induced by photodoping
The observation and control of interweaving spin, charge, orbital, and structural degrees of freedom in materials on ultrafast time scales reveal exotic quantum phenomena and enable new active forms of nanotechnology. Bond-
ing is the prime example of the relation between electronic and nuclear degrees of freedom. We report direct evidence illustrating that photoexcitation can be used for ultrafast control of the breaking and recovery of bonds in solids on unprecedented time scales, near the limit for nuclear motions. We describe experimental and theoretical studies of IrTe2 using femtosecond electron diffraction and density functional theory to investigate bonding instability. Ir-Ir dimerization shows an unexpected fast dissociation and recovery due to the filling of the antibonding dxy orbital. Bond length changes of 20% in IrTe2 are achieved by effectively addressing the bonds directly through this relaxation process. These results could pave the way to ultrafast switching between metastable structures by
photoinduced manipulation of the relative degree of bonding in this manner
Adjuvant hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with colon cancer at high risk of peritoneal carcinomatosis; the COLOPEC randomized multicentre trial
Background: The peritoneum is the second most common site of recurrence in colorectal cancer. Early detection of peritoneal carcinomatosis (PC) by imaging is difficult. Patients eventually presenting with clinically apparent PC have a poor prognosis. Median survival is only about five months if untreated and the benefit of palliative systemic chemotherapy is limited. Only a quarter of patients are eligible for curative treatment, consisting of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CR/HIPEC). However, the effectiveness depends highly on the extent of disease and the treatment is associated with a considerable complication rate. Methods/Design: The aim of this study is to determine the effectiveness of adjuvant HIPEC in preventing the development of PC in patients with colon cancer at high risk of peritoneal recurrence. This study will be performed in the nine Dutch HIPEC centres, starting in April 2015. Eligible for inclusion are patients who underwent curative resection for T4 or intra-abdominally perforated cM0 stage colon cancer. After resection of the primary tumour, 176 patients will be randomized to adjuvant HIPEC followed by routine adjuvant systemic chemotherapy in the experimental arm, or to systemic chemotherapy only in the control arm. Adjuvant HIPEC will be performed simultaneously or shortly after the primary resection. Oxaliplatin will be used as chemotherapeutic agent, for 30 min at 42-43 °C. Just before HIPEC, 5-fluorouracil and leucovorin will be administered intravenously. Primary endpoint is peritoneal disease-free survival at 18 months. Diagnostic laparoscopy will be performed routinely after 18 months postoperatively in both arms of the study in patients without evidence of disease based on routine follow-up using CT imaging and CEA. Discussion: Adjuvant HIPEC is assumed to reduce the expected 25 % absolute risk of PC in patients with T4 or perforated colon cancer to a risk of 10 %. This reduction is likely to translate into a prolonged overall survival. Trial registration number: NCT02231086 (Clinicaltrials.gov)
Prognostic Implications of Lateral Lymph Nodes in Rectal Cancer:A Population-Based Cross-sectional Study with Standardized Radiological Evaluation after Dedicated Training
BACKGROUND: There is an ongoing discussion regarding the prognostic implications of the presence, short-axis diameter, and location of lateral lymph nodes. OBJECTIVE: To analyze lateral lymph node characteristics, the role of downsizing on restaging MRI, and associated local recurrence rates for patients with cT3-4 rectal cancer after MRI re-review and training. DESIGN: Retrospective population-based cross-sectional study. SETTINGS: This collaborative project was led by local investigators from surgery and radiology departments in 60 Dutch hospitals. PATIENTS: A total of 3057 patients underwent rectal cancer surgery in 2016: 1109 had a cT3-4 tumor located ≤8 cm from the anorectal junction, of whom 891 received neoadjuvant therapy. MAIN OUTCOME MEASURES: Local recurrence and (ipsi) lateral local recurrence rates. RESULTS: Re-review identified 314 patients (35%) with visible lateral lymph nodes. Of these, 30 patients had either only long-stretched obturator (n = 13) or external iliac (n = 17) nodes, and both did not lead to any lateral local recurrences. The presence of internal iliac/obturator lateral lymph nodes (n = 284) resulted in 4-year local recurrence and lateral local recurrence rates of 16.4% and 8.8%, respectively. Enlarged (≥7 mm) lateral lymph nodes (n = 122) resulted in higher 4-year local recurrence (20.8%, 13.1%, 0%; p <.001) and lateral local recurrence (14.7%, 4.4%, 0%; p < 0.001) rates compared to smaller and no lateral lymph nodes, respectively. Visible lateral lymph nodes (HR 1.8 [1.1-2.8]) and enlarged lateral lymph nodes (HR 1.9 [1.1-3.5]) were independently associated with local recurrence in multivariable analysis. Enlarged lateral lymph nodes with malignant features had higher 4-year lateral local recurrence rates of 17.0%. Downsizing had no impact on lateral local recurrence rates. Enlarged lateral lymph nodes were found to be associated with higher univariate 4-year distant metastasis rates (36.4% vs 24.4%; p = 0.021), but this was not significant in multivariable analyses (HR 1.3 [0.9-1.]) and did not worsen overall survival. LIMITATIONS: This study was limited by the retrospective design and total number of patients with lateral lymph nodes. CONCLUSIONS: The risk of lateral local recurrence due to (enlarged) lateral lymph nodes was confirmed, but without the prognostic impact of downsizing after neoadjuvant therapy. These results point toward the incorporation of primary lateral lymph node size into treatment planning. See Video Abstract.</p
Long-range Angular Correlations On The Near And Away Side In P-pb Collisions At √snn=5.02 Tev
7191/Mar294
Robotic Control for Vibration Reduction of Swinging Products
Input shaping can effectively reduce residual vibrations of flexible systems induced by the reference signal. For the control of cranes, the usefulness of input shaping is well known and implemented. A big knowledge gap is noted to apply input shaping to robotic pick and place. For these applications, the shaped reference trajectory could result in a reduced overall settling time. A frequency domain and time domain view is presented for this purpose. The main contribution of this paper is the introduction of a formal proposition to relate the relative overshoot to the ratio of vibration and acceleration time. This enables the selection of the highest possible acceleration value to meet the overshoot specification. An experimental validation, confirms the performance improvement obtained for a cheese product packed in a liquid bag suspended by a vacuum suction cup gripper for a delta robot system