123 research outputs found
Global rigidity for totally nonsymplectic Anosov Z^k actions
We consider a totally nonsymplectic Anosov action of Z^k which is either
uniformly quasiconformal or pinched on each coarse Lyapunov distribution. We
show that such an action on a torus is C^\infty--conjugate to an action by
affine automorphisms. We also obtain similar global rigidity results for
actions on an arbitrary compact manifold assuming that the coarse Lyapunov
foliations are jointly integrable.Comment: This is the version published by Geometry & Topology on 24 July 200
Alzheimer's Disease-Related Dementias Summit 2022: National Research Priorities for the Investigation of Post-Traumatic Brain Injury Alzheimer's Disease and Related Dementias
Traumatic Brain Injury (TBI) is a risk factor for Alzheimer's disease and Alzheimer's disease related dementias (AD/ADRD) and otherwise classified post-traumatic neurodegeneration (PTND). Targeted research is needed to elucidate the circumstances and mechanisms through which TBI contributes to the initiation, development, and progression of AD/ADRD pathologies including multiple etiology dementia (MED). The National Institutes of Health hosts triennial ADRD summits to inform a national research agenda, and TBI was included for a second time in 2022. A multidisciplinary expert panel of TBI and dementia researchers was convened to re-evaluate the 2019 research recommendations for understanding TBI as an AD/ADRD risk factor and to assess current progress and research gaps in understanding post-TBI AD/ADRD. Refined and new recommendations were presented during the MED special topic session at the virtual ADRD Summit in March 2022. Final research recommendations incorporating broad stakeholder input are organized into four priority areas as follows: (1) Promote interdisciplinary collaboration and data harmonization to accelerate progress of rigorous, clinically meaningful research; (2) Characterize clinical and biological phenotypes of PTND associated with varied lifetime TBI histories in diverse populations to validate multimodal biomarkers; (3) Establish and enrich infrastructure to support multimodal longitudinal studies of individuals with varied TBI exposure histories and standardized methods including common data elements (CDEs) for ante-mortem and post-mortem clinical and neuropathological characterization; and (4) Support basic and translational research to elucidate mechanistic pathways, development, progression, and clinical manifestations of post-TBI AD/ADRDs. Recommendations conceptualize TBI as a contributor to MED and emphasize the unique opportunity to study AD/ADRD following known exposure, to inform disease mechanisms and treatment targets for shared common AD/ADRD pathways
Breast-cancer adjuvant therapy with zoledronic acid
Background: Data suggest that the adjuvant use of bisphosphonates reduces rates of recurrence and death in patients with early-stage breast cancer. We conducted a study to determine whether treatment with zoledronic acid, in addition to standard adjuvant therapy, would improve disease outcomes in such patients. Methods: In this open-label phase 3 study, we randomly assigned 3360 patients to receive standard adjuvant systemic therapy either with or without zoledronic acid. The zoledronic acid was administered every 3 to 4 weeks for 6 doses and then every 3 to 6 months to complete 5 years of treatment. The primary end point of the study was disease-free survival. A second interim analysis revealed that a prespecified boundary for lack of benefit had been crossed. Results: At a median follow-up of 59 months, there was no significant between-group difference in the primary end point, with a rate of disease-free survival of 77% in each group (adjusted hazard ratio in the zoledronic acid group, 0.98; 95% confidence interval [CI], 0.85 to 1.13; P=0.79). Disease recurrence or death occurred in 377 patients in the zoledronic acid group and 375 of those in the control group. The numbers of deaths — 243 in the zoledronic acid group and 276 in the control group — were also similar, resulting in rates of overall survival of 85.4% in the zoledronic acid group and 83.1% in the control group (adjusted hazard ratio, 0.85; 95% CI, 0.72 to 1.01; P=0.07). In the zoledronic acid group, there were 17 confirmed cases of osteonecrosis of the jaw (cumulative incidence, 1.1%; 95% CI, 0.6 to 1.7; P<0.001) and 9 suspected cases; there were no cases in the control group. Rates of other adverse effects were similar in the two study groups. Conclusions: These findings do not support the routine use of zoledronic acid in the adjuvant management of breast cancer. (Funded by Novartis Pharmaceuticals and the National Cancer Research Network; AZURE Current Controlled Trials number, ISRCTN79831382.
Breast-cancer Adjuvant Therapy With Zoledronic Acid
BACKGROUND: Data suggest that the adjuvant use of bisphosphonates reduces rates of recurrence and death in patients with early-stage breast cancer. We conducted a study to determine whether treatment with zoledronic acid, in addition to standard adjuvant therapy, would improve disease outcomes in such patients. METHODS: In this open-label phase 3 study, we randomly assigned 3360 patients to receive standard adjuvant systemic therapy either with or without zoledronic acid. The zoledronic acid was administered every 3 to 4 weeks for 6 doses and then every 3 to 6 months to complete 5 years of treatment. The primary end point of the study was disease-free survival. A second interim analysis revealed that a prespecified boundary for lack of benefit had been crossed. RESULTS: At a median follow-up of 59 months, there was no significant between-group difference in the primary end point, with a rate of disease-free survival of 77% in each group (adjusted hazard ratio in the zoledronic acid group, 0.98; 95% confidence interval [CI], 0.85 to 1.13; P = 0.79). Disease recurrence or death occurred in 377 patients in the zoledronic acid group and 375 of those in the control group. The numbers of deaths - 243 in the zoledronic acid group and 276 in the control group - were also similar, resulting in rates of overall survival of 85.4% in the zoledronic acid group and 83.1% in the control group (adjusted hazard ratio, 0.85; 95% CI, 0.72 to 1.01; P = 0.07). In the zoledronic acid group, there were 17 confirmed cases of osteonecrosis of the jaw (cumulative incidence, 1.1%; 95% CI, 0.6 to 1.7; P < 0.001) and 9 suspected cases; there were no cases in the control group. Rates of other adverse effects were similar in the two study groups. CONCLUSIONS: These findings do not support the routine use of zoledronic acid in the adjuvant management of breast cancer
The Effect of Water Immersion during Exercise on Cerebral Blood Flow
Introduction: Regular exercise induces recurrent increases in cerebrovascular perfusion. In peripheral arteries, such episodic increases in perfusion are responsible for improvement in arterial function and health. We examined the hypothesis that exercise during immersion augments cerebral blood flow velocity compared with intensity-matched land-based exercise.
Methods: Fifteen normotensive participants were recruited (26 ± 4 yr, 24.3 ± 1.9 kg·m−2). We continuously assessed mean arterial blood pressure, HR, stroke volume, oxygen consumption, and blood flow velocities through the middle and posterior cerebral arteries before, during, and after 20-min bouts of water- and land-based stepping exercise of matched intensity. The order in which the exercise conditions were performed was randomized between subjects. Water-based exercise was performed in 30°C water to the level of the right atrium.
Results: The water- and land-based exercise bouts were closely matched for oxygen consumption (13.3 mL·kg−1·min−1 (95% confidence interval (CI), 12.2–14.6) vs 13.5 mL·kg−1·min−1 (95% CI, 12.1–14.8), P = 0.89) and HR (95 bpm (95% CI, 90–101) vs 96 bpm (95% CI, 91–102), P = 0.65). Compared with land-based exercise, water-based exercise induced an increase in middle cerebral artery blood flow velocity (74 cm·s−1 (95% CI, 66–81) vs 67 cm·s−1 (95% CI, 60–74) P < 0.001), posterior cerebral artery blood flow velocity (47 cm·s−1 (95% CI, 40–53) vs 43 cm·s−1 (95% CI, 37–49), P < 0.001), mean arterial blood pressure (106 mm Hg (95% CI, 100–111) vs 101 mm Hg (95% CI, 95–106), P < 0.001), and partial pressure of expired CO2 (P ≤ 0.001).
Conclusions: Our findings suggest that water-based exercise augments cerebral blood flow, relative to land-based exercise of similar intensity, in healthy humans
Monoclonal antibody BTT1023 targeting vascular adhesion protein 1 for treating primary sclerosing cholangitis: BUTEO single-arm Phase II trial
Background: Primary sclerosing cholangitis is a progressive and fibrotic liver disease. Treatments remain inadequate, and patients with persistent elevations in activity of alkaline phosphatase are at greatest risk of disease progression. Studies in patient cohorts have implicated the serum amine oxidase vascular adhesion protein 1 in the pathophysiology of disease, including liver fibrogenesis. We hypothesised that blockade of serum amine oxidase by a monoclonal antibody would result in a reduction in liver fibrosis/injury, as evaluated by serum liver tests and other non-invasive markers of liver injury.Objectives: To evaluate the open-label effect on liver injury markers of treatment with the anti-vascular adhesion protein 1 monoclonal antibody BTT1023 in patients with primary sclerosing cholangitis over a 78-day treatment period.Design: A single-arm, two-stage, open-label, multicentre, Phase II clinical trial.Setting: Ambulatory liver disease practices in tertiary care hospitals.Participants: Patients with primary sclerosing cholangitis at risk of disease progression, based on elevated activity of serum alkaline phosphatase, and without evidence of infection, liver failure or advanced disease.Intervention: Seven intravenous infusions of BTT1023 (8 mg/kg of timolumab) over a 78-day treatment period. The intervention was split into a dose-confirmatory stage (to confirm pharmacokinetics), followed by a confirmed expansion cohort stage.Main outcome measures: Our primary outcome measure was patient response to treatment at day 99, measured by a reduction in activity of serum alkaline phosphatase of ≥ 25% from baseline to day 99. Secondary markers of efficacy were assessed based on evaluation of changes in markers of liver injury and liver fibrosis. Safety assessments were performed throughout. Results: Thirty-five patients were consented and screened for eligibility. Twenty-three patients were treated across the two stages of the trial. Interim assessment demonstrated a failure to meet the primary end point, leading to trial discontinuation on the grounds of futility. Multiple exploratory markers were evaluated in a final cohort of 22 patients (modified intention-to-treat analysis). No treatment-related effects were evident. No new safety concerns were seen.Conclusions: No preliminary evidence for disease modification was demonstrated.Limitations: It is clear that this study is limited in its design. Even if there were a better biomarker of fibrosis turnover that could be considered the ‘gold standard’, the design and duration would have had real-world resource limitations. With limited opportunity to test a new agent in large numbers of patients over a prolonged period, it was necessary to aim to see efficacy in a small cohort over a short period. Given the absence of any proven biochemical surrogate of disease activity in primary sclerosing cholangitis, alkaline phosphatase was chosen as an end point. This remains a difficult end point (yet one that does capture biliary injury) and, therefore, despite limitations, this study did demonstrate short-term safety.Future work: Future research will require attention to an ongoing debate regarding the optimal end points for assessing efficacy, as well as consideration of duration of treatment, even in early-phase studies. This raises the challenge of how to fund early experimental trials with ‘high risk of failure’ adequately to ensure that clearer results (negative or positive) arise by the end of the study.Trial registration: Current Controlled Trials ISRCTN11233255, EudraCT 2014-002393-37 and NCT02239211.Funding: This project was funded by the Efficacy and Mechanism Evaluation programme, a Medical Research Council and National Institute for Health Research (NIHR) partnership. This will be published in full in Efficacy and Mechanism Evaluation; Vol. 9, No. 1. See the NIHR Journals Library website for further project information
Dissociation between exercise-induced reduction in liver fat and changes in hepatic and peripheral glucose homoeostasis in obese patients with non-alcoholic fatty liver disease.
Non-alcoholic fatty liver disease (NAFLD) is associated with multi-organ (hepatic, skeletal muscle, adipose tissue) insulin resistance (IR). Exercise is an effective treatment for lowering liver fat but its effect on IR in NAFLD is unknown. We aimed to determine whether supervised exercise in NAFLD would reduce liver fat and improve hepatic and peripheral (skeletal muscle and adipose tissue) insulin sensitivity. Sixty nine NAFLD patients were randomized to 16 weeks exercise supervision (n=38) or counselling (n=31) without dietary modification. All participants underwent MRI/spectroscopy to assess changes in body fat and in liver and skeletal muscle triglyceride, before and following exercise/counselling. To quantify changes in hepatic and peripheral insulin sensitivity, a pre-determined subset (n=12 per group) underwent a two-stage hyperinsulinaemic euglycaemic clamp pre- and post-intervention. Results are shown as mean [95% confidence interval (CI)]. Fifty participants (30 exercise, 20 counselling), 51 years (IQR 40, 56), body mass index (BMI) 31 kg/m(2) (IQR 29, 35) with baseline liver fat/water % of 18.8% (IQR 10.7, 34.6) completed the study (12/12 exercise and 7/12 counselling completed the clamp studies). Supervised exercise mediated a greater reduction in liver fat/water percentage than counselling [Δ mean change 4.7% (0.01, 9.4); P<0.05], which correlated with the change in cardiorespiratory fitness (r=-0.34, P=0.0173). With exercise, peripheral insulin sensitivity significantly increased (following high-dose insulin) despite no significant change in hepatic glucose production (HGP; following low-dose insulin); no changes were observed in the control group. Although supervised exercise effectively reduced liver fat, improving peripheral IR in NAFLD, the reduction in liver fat was insufficient to improve hepatic IR
Ectopic lipid storage in non-alcoholic fatty liver disease is not mediated by impaired mitochondrial oxidative capacity in skeletal muscle
Background and Aims. Simple clinical algorithms including the Fatty Liver Index (FLI) and Lipid Accumulation Product (LAP) have been developed as a surrogate marker for Non-Alcoholic Fatty Liver Disease (NAFLD). These algorithms have been constructed using ultrasonography, a semi-quantitative method. This study aimed to validate FLI and LAP as measures of hepatic steatosis, as measured quantitatively by proton magnetic resonance spectroscopy (1H-MRS).
Methods. Data were collected from 168 patients with NAFLD and 168 controls who had undergone clinical, biochemical and anthropometric assessment in the course of research studies. Values of FLI and LAP were determined, and assessed both as predictors of the presence of hepatic steatosis (liver fat >5.5 %) and of actual liver fat content, as measured by 1H MRS. The discriminative ability of FLI and LAP was estimated using the area under the Receiver Operator Characteristic curve (AUROC). Since FLI can also be interpreted as a predictive probability of hepatic steatosis, we assessed how well calibrated it was in our cohort. Linear regression with prediction intervals was used to assess the ability of FLI and LAP to predict liver fat content.
Results. FLI and LAP discriminated between patients with and without hepatic steatosis with an AUROC of 0.79 (IQR= 0.74, 0.84) and 0.78 (IQR= 0.72, 0.83), although quantitative prediction of liver fat content was unsuccessful. Additionally, the algorithms accurately matched the observed percentages of patients with hepatic steatosis in our cohort.
Conclusions. FLI and LAP may be used clinically, and for metabolic and epidemiological research, to identify patients with hepatic steatosis, but not as surrogates for liver fat content
Minimal residual disease in Myeloma: Application for clinical care and new drug registration
The development of novel agents has transformed the treatment paradigm for multiple myeloma, with minimal residual disease (MRD) negativity now achievable across the entire disease spectrum. Bone marrow–based technologies to assess MRD, including approaches using next-generation flow and next-generation sequencing, have provided real-time clinical tools for the sensitive detection and monitoring of MRD in patients with multiple myeloma. Complementary liquid biopsy–based assays are now quickly progressing with some, such as mass spectrometry methods, being very close to clinical use, while others utilizing nucleic acid–based technologies are still developing and will prove important to further our understanding of the biology of MRD. On the regulatory front, multiple retrospective individual patient and clinical trial level meta-analyses have already shown and will continue to assess the potential of MRD as a surrogate for patient outcome. Given all this progress, it is not surprising that a number of clinicians are now considering using MRD to inform real-world clinical care of patients across the spectrum from smoldering myeloma to relapsed refractory multiple myeloma, with each disease setting presenting key challenges and questions that will need to be addressed through clinical trials. The pace of advances in targeted and immune therapies in multiple myeloma is unprecedented, and novel MRD-driven biomarker strategies are essential to accelerate innovative clinical trials leading to regulatory approval of novel treatments and continued improvement in patient outcomes
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