246 research outputs found
Hyperglycemia and prostate cancer recurrence in men treated for localized prostate cancer.
Background:Obesity is consistently linked with prostate cancer (PCa) recurrence and mortality, though the mechanism is unknown. Impaired glucose regulation, which is common among obese individuals, has been hypothesized as a potential mechanism for PCa tumor growth. In this study, we explore the relationship between serum glucose at time of treatment and risk of PCa recurrence following initial therapy.Methods:The study group comprised 1734 men treated with radical prostatectomy (RP) or radiation therapy (RT) for localized PCa between 2001-2010. Serum glucose levels closest to date of diagnosis were determined. PCa recurrence was determined based on PSA progression (nadir PSA+2 for RT; PSA0.2 for RP) or secondary therapy. Multivariate Cox regression was performed to determine whether glucose level was associated with biochemical recurrence after adjusting for age, race, body mass index, comorbidity, diagnosis of diabetes, Gleason Sum, PSA, treatment and treatment year.Results:Recurrence was identified in 16% of men over a mean follow-up period of 41 months (range 1-121 months). Those with elevated glucose (100 mg/dl) had a 50% increased risk of recurrence (HR 1.5, 95% CI: 1.1-2.0) compared with those with a normal glucose level (<100 mg/dl). This effect was seen in both those undergoing RP (HR 1.9, 95% CI: 1.0-3.6) and those treated with RT (HR 1.4, 95% CI: 1.0-2.0).Conclusions:Glucose levels at the time of PCa diagnosis are an independent predictor of PCa recurrence for men undergoing treatment for localized disease
Force spectroscopy in studying infection
Biophysical force spectroscopy tools - for example optical tweezers, magnetic
tweezers, atomic force microscopy, - have been used to study elastic,
mechanical, conformational and dynamic properties of single biological
specimens from single proteins to whole cells to reveal information not
accessible by ensemble average methods such as X-ray crystallography, mass
spectroscopy, gel electrophoresis and so on. Here we review the application of
these tools on a range of infection-related questions from antibody-inhibited
protein processivity to virus-cell adhesion. In each case we focus on how the
instrumental design tailored to the biological system in question translates
into the functionality suitable for that particular study. The unique insights
that force spectroscopy has gained to complement knowledge learned through
population averaging techniques in interrogating biomolecular details prove to
be instrumental in therapeutic innovations such as those in structure-based
drug design
Verification of the Crooks fluctuation theorem and recovery of RNA folding free energies
The description of nonequilibrium processes in nano-sized objects, where the
typical energies involved are a few times, is increasingly becoming central to
disciplines as diverse as condensed-matter physics, materials science, and
biophysics. Major recent developments towards a unified treatment of
arbitrarily large fluctuations in small systems are described by fluctuation
theorems that relate the probabilities of a system absorbing from or releasing
to the bath a given amount of energy in a nonequilibrium process. Here we
experimentally verify the Crooks Fluctuation Theorem (CFT) under weak and
strong nonequilibrium conditions by using optical tweezers to measure the
irreversible mechanical work during the unfolding and refolding of a small RNA
hairpin and an RNA three-helix junction. We also show that the CFT provides a
powerful way to obtain folding free energies in biomolecules by determining the
crossing between the unfolding and refolding irreversible work distributions.
The method makes it possible to obtain folding free energies in nonequilibrium
processes that dissipate up to of the average total work exerted, thereby
paving the way for reconstructing free energy landscapes along reaction
coordinates in nonequilibrium single-molecule experiments.Comment: PDF file, 19 pages. Supplementary information available online at
www.nature.co
Clinical factors of response in patients with advanced ovarian cancer participating in early phase clinical trials.
Drug resistance to conventional anticancer therapies is almost inevitable in patients with advanced ovarian cancer (AOC), limiting their available treatment options. Novel phase I trial therapies within a dedicated drug development unit may represent a viable alternative; however, there is currently little evidence for patient outcomes in such patients. To address this, we undertook a retrospective review of patients with AOC allocated to phase I trials in the Drug Development Unit at Royal Marsden Hospital (RMH) between June 1998 and October 2010. A total of 200 AOC patients with progressive disease were allocated to ≥1 trial each, with a total of 281 allocations. Of these, 135 (68%) patients commenced ≥1 trial (mean 1.4 [1-8]), totaling 216 allocated trials; 65 (32%) patients did not start due to deterioration resulting from rapidly progressive disease (63 patients) or patient choice (2 patients). Response Evaluation Criteria in Solid Tumours (RECIST) complete/partial responses (CR/PR) were observed in 43 (20%) of those starting trials, including those on poly(ADP-ribose) polymerase (PARP) inhibitors (18/79 [23%]), antiangiogenics (9/65 [14%]) and chemotherapy combinations (14/43 [33%]). Factors associated with CR/PR included: fewer prior treatments, platinum-sensitive disease, CR/PR with prior therapy, (the United States-based) Eastern Cooperative Oncology Group (ECOG) performance status score, fewer metastatic sites, higher albumin and haemoglobin levels, lower white cell counts and baseline CA125 levels, germline BRCA1/2 mutations and better RMH Prognostic Score. Mean survival was 32° months for patients who achieved CR/PR. Treatments were generally well tolerated. Most patients with AOC (134/200 [67%]) received ≥1 subsequent line of therapy after phase I trials. Our data suggest that phase I trial referrals should be considered earlier in the AOC treatment pathway and before the onset of rapid disease progression particularly with the emergence of promising novel agents in the era of precision medicine
First-line treatment for advanced ovarian cancer: paclitaxel, platinum and the evidence
Four large randomised trials of paclitaxel in combination with platinum against a platinum-based control treatment have now been published in full, representing around 88% (3588 out of 4057) of patients randomised into the eight known trials of this question. There is substantial heterogeneity in the results of these four trials. Four main explanations for this heterogeneity have been proposed: differences in the extent and timing of ‘crossover’ to taxanes in the control groups; differences in the types of patient included; differences in the effectiveness of the research regimens used; differences in the effectiveness of the control regimens used. In this study we examine whether any of these explanations is consistent with the pattern of results seen in these trials. Each explanation suggests that a particular characteristic of each trial was responsible for the results observed. For each explanation the trials were split into groups according to that characteristic, in order to partition the total heterogeneity into that seen ‘within’ and ‘between’ groups of trials. If a particular explanation was consistent with the pattern of results, we would expect to see relatively little heterogeneity within each group of trial results viewed in this way, with most of the heterogeneity being between groups which are dissimilar with respect to the key characteristic. Heterogeneity ‘within’ and ‘between’ groups was formally compared using the F-ratio. If any explanation appeared to be consistent with the results of the trials, it was considered whether the explanation was also consistent with other evidence available about these regimens. Only one explanation appeared to be consistent with the pattern of results seen in these trials, and that was differences in effectiveness of the control arms used in these trials. This suggests that the very positive results in favour of paclitaxel/cisplatin seen in two of the trials may have been due to the use of a suboptimal control arm. There is no direct evidence about the relative effectiveness of the control arms used in these trials, but indirect evidence is consistent with the conclusion that the cyclophosphamide/cisplatin regimen used in two of the trials may be less effective than the control regimens used in the other trials. Specific concerns about the choice of a cyclophosphamide/cisplatin control arm in the first of these trials to report were raised before the results of the other trials were known, i.e. before any heterogeneity had been observed. Further investigation of this question would be useful. In the meantime, given all of the randomised evidence on the efficacy and toxicity associated with the regimens used in these trials, we conclude that single agent carboplatin is a safe and effective first-line treatment for women with advanced ovarian cancer
Continuous ambulatory peritoneal dialysis: pharmacokinetics and clinical outcome of paclitaxel and carboplatin treatment
Purpose: Administration of chemotherapy in patients with renal failure, treated with hemodialysis or continuous ambulatory peritoneal dialysis (CAPD) is still a challenge and literature data is scarce. Here we present a case study of a patient on CAPD, treated with weekly and three-weekly paclitaxel/ carboplatin for recurrent ovarian cancer. Experimental: During the first, second and ninth cycle of treatment, blood, urine and CAPD samples were collected for pharmacokinetic analysis of paclitaxel and total and unbound carboplatin-derived platinum. Results: Treatment was well tolerated by the patient. No excessive toxicity was observed and at the e
Does interhospital transfer improve outcome of acute myocardial infarction? A propensity score analysis from the Cardiovascular Cooperative Project
<p>Abstract</p> <p>Background</p> <p>Many patients suffering acute myocardial infarction (AMI) are transferred from one hospital to another during their hospitalization. There is little information about the outcomes related to interhospital transfer. The purpose of this study was to compare processes and outcomes of AMI care among patients undergoing interhospital transfer with special attention to the impact on mortality in rural hospitals.</p> <p>Methods</p> <p>National sample of Medicare patients in the Cooperative Cardiovascular Study (n = 184,295). Retrospective structured medical record review of AMI hospitalizations. Descriptive study using a retrospective propensity score analysis of clinical and administrative data for 184,295 Medicare patients admitted with clinically confirmed AMI to 4,765 hospitals between February 1994 and July 1995. Main outcome measure included: 30-day mortality, administration of aspirin, beta-blockers, ACE-inhibitors, and thrombolytic therapy.</p> <p>Results</p> <p>Overall, 51,530 (28%) patients underwent interhospital transfer. Transferred patients were significantly younger, less critically ill, and had lower comorbidity than non-transferred patients. After propensity-matching, patients who underwent interhospital transfer had better quality of care anlower mortality than non-transferred patients. Patients cared for in a rural hospital had similar mortality as patients cared for in an urban hospital.</p> <p>Conclusion</p> <p>Transferred patients were vastly different than non-transferred patients. However, even after a rigorous propensity-score analysis, transferred patients had lower mortality than non-transferred patients. Mortality was similar in rural and urban hospitals. Identifying patients who derive the greatest benefit from transfer may help physicians faced with the complex decision of whether to transfer a patient suffering an acute MI.</p
Reliability of Transcriptional Cycles and the Yeast Cell-Cycle Oscillator
A recently published transcriptional oscillator associated with the yeast cell cycle provides clues and raises questions about the mechanisms underlying autonomous cyclic processes in cells. Unlike other biological and synthetic oscillatory networks in the literature, this one does not seem to rely on a constitutive signal or positive auto-regulation, but rather to operate through stable transmission of a pulse on a slow positive feedback loop that determines its period. We construct a continuous-time Boolean model of this network, which permits the modeling of noise through small fluctuations in the timing of events, and show that it can sustain stable oscillations. Analysis of simpler network models shows how a few building blocks can be arranged to provide stability against fluctuations. Our findings suggest that the transcriptional oscillator in yeast belongs to a new class of biological oscillators
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