A novel polymerization mechanism transformation strategy, involving anionic ring‐opening polymerization and photoinduced cationic polymerization, is successfully applied for the synthesis of poly(ethylene oxide)‐graft‐poly(isobutyl vinyl ether) (PEO‐g‐PIBVE). First, poly(ethylene oxide‐co‐ethoxyl vinyl glycidyl ether) [P(EO‐co‐EVGE)] is synthesized by living anionic polymerization. The vinyl moieties of the functional PEO‐based polymer are converted to the hydrogen iodide adduct by photolysis of diphenyliodonium iodide, monitored using NMR spectroscopy. A modified mode of Lewis acid‐catalyzed living cationic polymerization is performed as a “grafting from” method to generate PIBVE segments grafted onto the PEO main chain. Both the intermediates and the final graft copolymers are characterized by gel‐permeation chromatography (GPC) and 1H NMR analysis.
Photochemically mediated atom transfer radical polymerization of vinyl monomers is successfully activated by ecofriendly heterogeneous mesoporous graphitic carbon nitride (mpg‐C3N4). This method pertains to the use of mpg‐C3N4 as photoactivator for reduction of initially loaded copper(II) species, thus promoting the in situ formation of the copper(I) species. The controlled nature of the polymerizations in both natural sunlight and UV‐light irradiation at ambient temperature is confirmed by the good agreement of the kinetics of the polymerization with theoretical values. The light on–off experiments demonstrate that polymerizations are clearly initiated and moderated by either UV light or sunlight.
Non-dipper blood pressure (NDP) as an indicator of autonomic dysfunction could be associated with hypertensive response to exercise (HRE) in diabetic patients. HRE was determined as a predictor of development of unborn hypertension. We aimed to investigate if any correlation among NDP and HRE in normotensive type 2 diabetic patients. A total of 59 consecutive type 2 diabetic patients without history of hypertension and with normal blood pressure (BP) on ambulatory blood pressure monitoring (ABPM) were enrolled to the study. We divided the study population in to two groups depending on their BP on ABPM as dipper (group 1) or non-dipper (group 2). There were 22 patients (mean age 49.5?±?7 and 10 male) in group 1 and 37 patients (mean age 53.1?±?10 and 14 male) in group 2. Daytime diastolic and mean BP of dippers and night time systolic and mean BP of non-dippers were significantly higher. HRE was not significantly different between groups (59% vs. 62%, p?=?0.820). Hemodynamic parameters during the exercise test were similar. At multivariate linear regression analysis, resting office systolic blood pressure (SBP) (r?=?0.611, p?0.001), male sex (r?=?0.266, p?=?0.002) and age (r?=?0.321, p?=?0.010) were independently correlated with peak exercises SBP. Logistic regression analyses identified the resting office SBP (OR 1.191, 95% CI 1.080–1.313; p?0.001) and age (OR 1.161, 95% CI 1.038–1.298; p?=?0.012) were independent predictors of HRE. This study revealed that HRE is not related with non-dipper BP in diabetic patients. This study could inspire to further studies to explore the main reasons of HRE in diabetes mellitus. 相似文献
Thoracic radiography and high resolution computerized tomography is used to diagnose pulmonary infections in immunosuppressed patients, although in some cases these do not provide enough information about the lesion. Dynamic contrast‐enhanced magnetic resonance imaging may be useful in these cases, especially for the characterization of cavitary lesions and assessment of their contrast diffusion. 相似文献
A synchronized dyshomeostasis of extra- and intracellular Ca(2+), expressed as plasma ionized hypocalcemia and excessive intracellular Ca(2+) accumulation, respectively, represents a common pathophysiologic scenario that accompanies several diverse disorders. These include low-renin and salt-sensitive hypertension, primary aldosteronism and hyperparathyroidism, congestive heart failure, acute and chronic hyperadrenergic stressor states, high dietary Na(+), and low dietary Ca(2+) with hypovitaminosis D. Homeostatic responses are invoked to restore normal extracellular [Ca(2+)](o), including increased plasma levels of parathyroid hormone and 1,25(OH)(2)D(3). However, in cardiomyocytes these calcitropic hormones concurrently promote cytosolic free [Ca(2+)](i) and mitochondrial [Ca(2+)](m) overloading. The latter sets into motion organellar-based oxidative stress, in which the rate of reactive oxygen species generation overwhelms their detoxification by endogenous antioxidant defenses, including those related to intrinsically coupled increments in intracellular Zn(2+). In turn, the opening potential of the mitochondrial permeability transition pore increases, allowing for osmotic swelling and ensuing organellar degeneration. Collectively, these pathophysiologic events represent the major components to a mitochondriocentric signal-transducer-effector pathway to cardiomyocyte necrosis. From necrotic cells, there follows a spillage of intracellular contents, including troponins, and a subsequent wound healing response with reparative fibrosis or scarring. Taken together, the loss of terminally differentiated cardiomyocytes from this postmitotic organ and the ensuing replacement fibrosis each contribute to the adverse structural remodeling of myocardium and progressive nature of heart failure. In conclusion, hormone-induced ionized hypocalcemia and intracellular Ca(2+) overloading comprise a pathophysiologic cascade common to diverse disorders and that initiates a mitochondriocentric pathway to nonischemic cardiomyocyte necrosis. 相似文献
Randomized trials have established the benefit of medical therapy and revascularization in the treatment of acute myocardial infarction (MI). Cancer and cardiovascular disease are the 2 most common diseases worldwide. In clinical practice, cancer patients are frequently afflicted with MI. The benefit of medical and/or revascularization therapy in the cancer population with MI is less well known.
Hypothesis:
Medical and revascularization therapy reduces mortality in cancer patients with MI.
Methods:
After approval by the institutional review board, we retrospectively reviewed all patients with a discharge diagnosis of acute MI who were admitted to the University of Texas MD Anderson Cancer Center between December 2000 and October 2006 and evaluated the association between cardiac treatments with survival outcomes.
Results:
A total of 456 patients with a discharge diagnosis of acute MI were identified and included in the study, of which 386 had non–ST‐segment elevation MI (NSTEMI) and 70 had ST‐segment elevation MI (STEMI). Compared with patients with NSTEMI, patients who had STEMI were more often prescribed aspirin (66% vs 43%; P = 0.004), β‐blockers (61% vs 46%; P = 0.018), and thrombolytic therapy (9% vs 0.3%; P = 0.0001). In the multivariable analysis, aspirin use was associated with a 23% decreased risk of death (hazard ratio [HR]: 0.77, 95% confidence interval [CI]: 0.60‐0.98, P = 0.033) and β‐blocker use was associated with a 36% decreased risk of death (HR: 0.64, 95% CI: 0.51–0.81, P = 0.0002). Statins (HR: 0.82, P = 0.18) and catheter‐based revascularization (HR: 0.57, P = 0.09) did not have an impact on the risk of death. Compared with patients with limited cancer, advanced cancer patients were twice as likely to die (HR: 2.12, 95 CI: 1.47–3.04, P < 0.0001). Previous chemotherapy (P = 0.005) and chest radiotherapy (P = 0.017) were associated with increased 1‐year mortality, whereas hyperlipidemia (P = 0.018) was protective.
Conclusions:
In this study of cancer patients with MI, medical therapy with aspirin and β‐blockers was associated with improved survival. The authors have no funding, financial relationships, or conflicts of interest to disclose. 相似文献