149 research outputs found
No elliptic islands for the universal area-preserving map
A renormalization approach has been used in \cite{EKW1} and \cite{EKW2} to
prove the existence of a \textit{universal area-preserving map}, a map with
hyperbolic orbits of all binary periods. The existence of a horseshoe, with
positive Hausdorff dimension, in its domain was demonstrated in \cite{GJ1}. In
this paper the coexistence problem is studied, and a computer-aided proof is
given that no elliptic islands with period less than 20 exist in the domain. It
is also shown that less than 1.5% of the measure of the domain consists of
elliptic islands. This is proven by showing that the measure of initial
conditions that escape to infinity is at least 98.5% of the measure of the
domain, and we conjecture that the escaping set has full measure. This is
highly unexpected, since generically it is believed that for conservative
systems hyperbolicity and ellipticity coexist
The VEGF pathway and the AKT/mTOR/p70S6K1 signalling pathway in human epithelial ovarian cancer
Vascular endothelial growth factor (VEGF)-A inhibitors exhibit unseen high responses and toxicity in recurrent epithelial ovarian cancer suggesting an important role for the VEGF/VEGFR pathway. We studied the correlation of VEGF signalling and AKT/mTOR signalling. Using a tissue microarray of clinical samples (N=86), tumour cell immunohistochemical staining of AKT/mTOR downstream targets, pS6 and p4E-BP1, together with tumour cell staining of VEGF-A and pVEGFR2 were semi-quantified. A correlation was found between the marker for VEGFR2 activation (pVEGFR2) and a downstream target of AKT/mTOR signalling (pS6) (R=0.29; P=0.002). Additional gene expression analysis in an independent cDNA microarray dataset (N=24) showed a negative correlation (R=−0.73, P<0.0001) between the RPS6 and the VEGFR2 gene, which is consistent as the gene expression and phosphorylation of S6 is inversely regulated. An activated tumour cell VEGFR2/AKT/mTOR pathway was associated with increased incidence of ascites (χ2, P=0.002) and reduced overall survival of cisplatin–taxane-based patients with serous histology (N=32, log-rank test, P=0.04). These data propose that VEGF-A signalling acts on tumour cells as a stimulator of the AKT/mTOR pathway. Although VEGF-A inhibitors are classified as anti-angiogenic drugs, these data suggest that the working mechanism has an important additional modality of targeting the tumour cells directly
Repair of an inguinoscrotal hernia containing the urinary bladder: a case report
<p>Abstract</p> <p>Introduction</p> <p>Cases of patients with inguinoscrotal hernia containing the urinary bladder are very rare. These patients usually present with frequent episodes of urinary tract infection, difficulty in walking, pollakisuria and difficulty in initiating micturition because of incarceration of the urinary bladder into the scrotum.</p> <p>Case presentation</p> <p>We describe the case of an 80-year-old Caucasian man with an incarcerated urinary bladder into the scrotum who underwent surgical repair with mesh.</p> <p>Conclusions</p> <p>Diagnosis of such cases often requires not only clinical examination but also specialized radiological examinations to show the ectopic position of the urinary bladder. Surgical repair in these patients is a real challenge for surgeons.</p
Intraoperative assessment and reporting of radical prostatectomy specimens to guide nerve-sparing surgery in prostate cancer patients (NeuroSAFE)
AIMS: Radical prostatectomy for prostate cancer is frequently complicated by urinary incontinence and erectile dysfunction. Nerve-sparing surgery reduces the risk of post-operative complications and can be optimized using intraoperative frozen sections of the adjacent neurovascular structure (NeuroSAFE). The aim of t
Genomic aberrations relate early and advanced stage ovarian cancer
Background Because of the distinct clinical presentation of early and advanced stage ovarian cancer, we aim to clarify whether these disease entities are solely separated by time of diagnosis or whether they arise from distinct molecular events. Methods Sixteen early and sixteen advanced stage ovarian carcinomas, matched for histological subtype and differentiation grade, were included. Genomic aberrations were compared for each early and advanced stage ovarian cancer by array comparative genomic hybridization. To study how the aberrations correlate to the clinical characteristics of the tumors we clustered tumors based on the genomic aberrations. Results The genomic aberration patterns in advanced stage cancer equalled those in early stage, but were more frequent in advanced stage (p=0.012). Unsupervised clustering based on genomic aberrations yielded two clusters that significantly discriminated early from advanced stage (p= 0.001), and that did differ significantly in survival (p= 0.002). These clusters however did give a more accurate prognosis than histological subtype or differentiation grade. Conclusion This study indicates that advanced stage ovarian cancer either progresses from early stage or from a common precursor lesion but that they do not arise from distinct carcinogenic molecular events. Furthermore, we show that array comparative genomic hybridization has the potential to identify clinically distinct patients
Comedonecrosis Gleason pattern 5 is associated with worse clinical outcome in operated prostate cancer patients
Individual growth patterns and cribriform architecture are increasingly considered in risk stratification and clinical decision-making in men with prostate cancer. Our objective was to establish the prognostic value of individual Gleason 5 patterns in a radical prostatectomy (RP) cohort. We reviewed 1064 RPs and recorded Grade Group (GG), pT-stage, surgical margin status, Gleason 4 and 5 growth patterns as well as intraductal carcinoma. The clinical endpoints were biochemical recurrence and post-operative distant metastasis. Gleason pattern 5 was present in 339 (31.9%) RPs, of which 47 (4.4%) presented as primary, 166 (15.6%) as secondary, and 126 (11.8%) as tertiary pattern. Single cells/cords were present in 321 (94.7%) tumors with Gleason pattern 5, solid fields in 90 (26.5%), and comedonecrosis in invasive carcinoma in 32 (9.4%) tumors. Solid fields demonstrated either a small nested morphology (n = 50, 14.7%) or medium to large solid fields (n = 61, 18.0%). Cribriform architecture was present in 568 (53.4%) RPs. Medium to large solid fields and comedonecrosis coincided with cribriform architecture in all specimens, and were not observed in cribriform-negative cases. In multivariable analysis adjusted for Prostate-Specific Antigen, pT-stage, GG, surgical margin status and lymph node metastases, cribriform architecture (Hazard Ratio (HR) 9.9; 95% Confidence Interval (CI) 3.9-25.5, P < 0.001) and comedonecrosis (HR 2.1, 95% CI 1.2-3.7, P = 0.01) were independent predictors for metastasis-free survival, while single cells/cords (HR 1.2; 95% CI 0.7-1.8, P = 0.55) and medium to large solid fields (HR 1.6, 95% CI 0.9-2.7, P = 0.09) were not. In conclusion, comedonecrosis in invasive carcinoma is an independent prognostic Gleason 5 pattern for metastasis-free survival after RP. These data support the current recommendations to routinely include cribriform pattern in pathology reports and indicate that comedonecrosis should also be commented on.Prostatic carcinom
Dynamics of the Universal Area-Preserving Map Associated with Period Doubling: Hyperbolic Sets
It is known that the famous Feigenbaum-Coullet-Tresser period doubling
universality has a counterpart for area-preserving maps of {\fR}^2. A
renormalization approach has been used in \cite{EKW1} and \cite{EKW2} in a
computer-assisted proof of existence of a "universal" area-preserving map
-- a map with orbits of all binary periods 2^k, k \in \fN. In this paper, we
consider maps in some neighbourhood of and study their dynamics.
We first demonstrate that the map admits a "bi-infinite heteroclinic
tangle": a sequence of periodic points , k \in \fZ, |z_k|
\converge{{k \to \infty}} 0, \quad |z_k| \converge{{k \to -\infty}} \infty,
whose stable and unstable manifolds intersect transversally; and, for any N
\in \fN, a compact invariant set on which is homeomorphic to a
topological Markov chain on the space of all two-sided sequences composed of
symbols. A corollary of these results is the existence of {\it unbounded}
and {\it oscillating} orbits.
We also show that the third iterate for all maps close to admits a
horseshoe. We use distortion tools to provide rigorous bounds on the Hausdorff
dimension of the associated locally maximal invariant hyperbolic set: 0.7673
\ge {\rm dim}_H(\cC_F) \ge \varepsilon \approx 0.00044 e^{-1797}.$
Food Acceptability in Field Studies with US Army Men and Women: Relationship with Food Intake and Food Choice After Repeated Exposures
Laboratory data with single exposures showed that palatability has a positive relationship with food intake. The question addressed in this study is whether this relationship also holds over repeated exposures in non-laboratory contexts in more natural environments. The data were collected in four field studies, lasting 4–11 days with 307 US Army men and 119 Army women, and comprised 5791 main meals and 8831 snacks in total. Acceptability was rated on the nine point hedonic scale, and intake was registered in units of 1/4, 1/2, 3/4, or 1 or more times of the provided portion size. Correlation coefficients between individual acceptability ratings and intakes varied from 0.22 to 0.62 for the main meals (n=193–2267), and between 0.13 and 0.56 for the snacks (n=304–2967). The likelihood of choosing a meal for the second time was positively related to the acceptability rating of the meal when it was consumed for the first time. The results reinforce the importance of liking in food choice and food intake/choice behavior. However, the magnitude of the correlation coefficients between acceptability ratings and food intake suggest that environmental factors also have an important role in determining intake and choice
Time to Recurrence and Survival in Serous Ovarian Tumors Predicted from Integrated Genomic Profiles
Serous ovarian cancer (SeOvCa) is an aggressive disease with differential and often inadequate therapeutic outcome after standard treatment. The Cancer Genome Atlas (TCGA) has provided rich molecular and genetic profiles from hundreds of primary surgical samples. These profiles confirm mutations of TP53 in ∼100% of patients and an extraordinarily complex profile of DNA copy number changes with considerable patient-to-patient diversity. This raises the joint challenge of exploiting all new available datasets and reducing their confounding complexity for the purpose of predicting clinical outcomes and identifying disease relevant pathway alterations. We therefore set out to use multi-data type genomic profiles (mRNA, DNA methylation, DNA copy-number alteration and microRNA) available from TCGA to identify prognostic signatures for the prediction of progression-free survival (PFS) and overall survival (OS). prediction algorithm and applied it to two datasets integrated from the four genomic data types. We (1) selected features through cross-validation; (2) generated a prognostic index for patient risk stratification; and (3) directly predicted continuous clinical outcome measures, that is, the time to recurrence and survival time. We used Kaplan-Meier p-values, hazard ratios (HR), and concordance probability estimates (CPE) to assess prediction performance, comparing separate and integrated datasets. Data integration resulted in the best PFS signature (withheld data: p-value = 0.008; HR = 2.83; CPE = 0.72).We provide a prediction tool that inputs genomic profiles of primary surgical samples and generates patient-specific predictions for the time to recurrence and survival, along with outcome risk predictions. Using integrated genomic profiles resulted in information gain for prediction of outcomes. Pathway analysis provided potential insights into functional changes affecting disease progression. The prognostic signatures, if prospectively validated, may be useful for interpreting therapeutic outcomes for clinical trials that aim to improve the therapy for SeOvCa patients
MicroRNA-21 regulates breast cancer invasion partly by targeting tissue inhibitor of metalloproteinase 3 expression
<p>Abstract</p> <p>Background</p> <p>MicroRNAs are non-coding RNA molecules that posttranscriptionally regulate expression of target genes and have been implicated in the progress of cancer proliferation, differentiation and apoptosis. The aim of this study was to determine whether microRNA-21 (miR-21), a specific microRNA implicated in multiple aspects of carcinogenesis, impacts breast cancer invasion by regulating the tissue inhibitor of metalloproteinase 3 (TIMP3) gene.</p> <p>Methods</p> <p>miR-21 expression was investigated in 32 matched breast cancer and normal breast tissues, and in four human breast cancer cell lines, by Taqman quantitative real-time PCR. Cell invasive ability was determined by matrigel invasion assay in vitro, in cells transfected with miR-21 or anti-miR-21 oligonucleotides. In addition, the regulation of tissue inhibitor of metalloproteinase 3 (TIMP3) by miR-21 was evaluated by western blotting and luciferase assays.</p> <p>Results</p> <p>Of the 32 paired samples analyzed, 25 breast cancer tissues displayed overexpression of miR-21 in comparison with matched normal breast epithelium. Additionally, incidence of lymph node metastasis closely correlated with miR-21 expression, suggesting a role for miR-21 in metastasis. Similarly, each of the four breast cancer cell lines analyzed overexpressed miR-21, to varied levels. Further, cells transfected with miR-21 showed significantly increased matrigel invasion compared with control cells, whereas transfection with anti-miR-21 significantly decreased cell invasion. Evaluation of TIMP3 protein levels, a peptidase involved in extarcellular matrix degredation, inversely correlated with miR-21 expression.</p> <p>Conclusion</p> <p>As knockdown of miR-21 increased TIMP3 protein expression and luciferase reporter activity, our data suggests that miR-21 could promote invasion in breast cancer cells via its regulation of TIMP3.</p
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