Abstract Induced pluripotent stem cells (iPSCs) hold great promise as a cell source for regenerative medicine yet its culture, maintenance of pluripotency and induction of differentiation remain ...challenging. Conversely, graphene (G) and graphene oxide (GO) have captured tremendous interests in the fields of materials science, physics, chemistry and nanotechnology. Here we report on that G and GO can support the mouse iPSCs culture and allow for spontaneous differentiation. Intriguingly, G and GO surfaces led to distinct cell proliferation and differentiation characteristics. In comparison with the glass surface, iPSCs cultured on the G surface exhibited similar degrees of cell adhesion and proliferation while iPSCs on the GO surface adhered and proliferated at a faster rate. Moreover, G favorably maintained the iPSCs in the undifferentiated state while GO expedited the differentiation. The iPSCs cultured on both G and GO surfaces spontaneously differentiated into ectodermal and mesodermal lineages without significant disparity, but G suppressed the iPSCs differentiation towards the endodermal lineage whereas GO augmented the endodermal differentiation. These data collectively demonstrated that the different surface properties of G and GO governed the iPSCs behavior and implicate the potentials of graphene-based materials as a platform for iPSCs culture and diverse applications.
A model of size effects in nano-indentation Huang, Y.; Zhang, F.; Hwang, K.C. ...
Journal of the mechanics and physics of solids,
08/2006, Letnik:
54, Številka:
8
Journal Article
Recenzirano
The indentation hardness–depth relation established by Nix and Gao 1998. Indentation size effects in crystalline materials: a law for strain gradient plasticity. J. Mech. Phys. Solids 46, 411–425 ...agrees well with the micro-indentation but not nano-indentation hardness data. We establish an analytic model for nano-indentation hardness based on the maximum allowable density of geometrically necessary dislocations. The model gives a simple relation between indentation hardness and depth, which degenerates to Nix and Gao 1998. Indentation size effects in crystalline materials: a law for strain gradient plasticity. J. Mech. Phys. Solids 46, 411–425 for micro-indentation. The model agrees well with both micro- and nano-indentation hardness data of MgO and iridium.
Abstract After myocardial infarction (MI), the heart undergoes fibrotic pathological remodeling instead of repair and regeneration. With multiple pathologies developing after MI, treatment using ...several proteins is expected to address this range of pathologies more effectively than a single-agent therapy. A factorial design of experiments study guided us to combine three complementary factors in one injection: tissue inhibitor of metalloproteinases-3 (TIMP-3) was embedded in a fibrin gel for signaling in the initial phase of the treatment, while basic fibroblast growth factor (FGF-2) and stromal cell-derived factor 1-alpha (SDF-1α) were embedded in heparin-based coacervates for sustained release and distributed within the same fibrin gel to exert their effects over a longer period. The gel was then tested in a rat model of myocardial infarction. Contractility of rat hearts treated with the protein coacervate-gel composite stabilized and slightly improved after the first week while contractility continued to decrease in rats treated with free proteins or saline over the 8 week study period. Hearts receiving the protein coacervate-gel composite treatment also exhibited reduced ventricular dilation, inflammation, fibrosis, and extracellular matrix (ECM) degradation. Revascularization, cardiomyocyte preservation, stem cell homing, and increased myocardial strain likely all contributed to the repair. This study demonstrates the potential of a multifactorial therapeutic approach in MI, using three complementary proteins delivered sequentially for comprehensive healing. The study also shows the necessity of controlled delivery for growth factors and cytokines to be an effective treatment.
Only a few clinical trials have been conducted in patients with advanced pancreatic cancer after failure of first-line gemcitabine-based chemotherapy. Therefore, there is no current consensus on the ...treatment of these patients. We conducted a randomised phase II study of the modified FOLFIRI.3 (mFOLFIRI.3; a regimen combining 5-fluorouracil (5-FU), folinic acid, and irinotecan) and modified FOLFOX (mFOLFOX; a regimen combining folinic acid, 5-FU, and oxaliplatin) regimens as second-line treatments in patients with gemcitabine-refractory pancreatic cancer.
The primary end point was the 6-month overall survival rate. The mFOlFIRI.3 regimen consisted of irinotecan (70 mg m(-2); days 1 and 3), leucovorin (400 mg m(-2); day 1), and 5-FU (2000 mg m(-2); days 1 and 2) every 2 weeks. The mFOLFOX regimen was composed of oxaliplatin (85 mg m(-2); day 1), leucovorin (400 mg m(-2); day 1), and 5-FU (2000 mg m(-2); days 1 and 2) every 2 weeks.
Sixty-one patients were randomised to mFOLFIRI.3 (n=31) or mFOLFOX (n=30) regimen. The six-month survival rates were 27% (95% confidence interval (CI)=13-46%) and 30% (95% CI=15-49%), respectively. The median overall survival periods were 16.6 and 14.9 weeks, respectively. Disease control was achieved in 23% (95% CI=10-42%) and 17% patients (95% CI=6-35%), respectively. The number of patients with at least one grade 3/4 toxicity was identical (11 patients, 38%) in both groups: neutropenia (7 patients under mFOLFIRI.3 regimen vs 6 patients under mFOLFOX regimen), asthaenia (1 vs 4), vomiting (3 in both), diarrhoea (2 vs 0), and mucositis (1 vs 2).
Both mFOLFIRI.3 and mFOLFOX regimens were tolerated with manageable toxicity, offering modest activities as second-line treatments for patients with advanced pancreatic cancer, previously treated with gemcitabine.
"Transcriptionally different" medulloblastoma groups are associated with specific signaling pathway abnormalities; hence, they may present with distinct imaging manifestations. In this study, we ...sought to describe the MR imaging features of wingless-type-subgroup medulloblastomas with embryologic correlations.
Pre- and postoperative imaging studies of 16 patients with wingless-type-subgroup medulloblastoma were evaluated for tumor location, involvement of surrounding CSF spaces or parenchymal structures, conventional and DWI signal properties, and postsurgical damage patterns. Laterality scores were assigned to tumors at each step in the evaluation process. Continuous variables were summarized by using descriptive statistics. The Wilcoxon signed rank test was performed to compare laterality scores. To determine the interobserver variability, we computed the intraclass correlation and Cohen κ coefficients.
Wingless-type-subgroup medulloblastomas in our series were histopathologically "classic." Wingless-type-subgroup medulloblastomas occur in specific sites, with involvement of the foramen of Luschka (75%), the fourth ventricle (68.75%), the cisterna magna (31.25%), and the cerebellopontine angle cistern (18.75%). Laterality scores were low (<2) when preoperative primary and secondary anatomic features were evaluated separately, but they increased (>2) when all pre- and postoperative anatomic features were considered. Results were statistically shown to be reproducible (interclass correlation coefficient, 0.71-0.94; Cohen κ, 0.63-1.00). On the basis of anatomic lesion patterns, 4 location-based subtypes may be distinguished: 1) midline-intraventricular, 2) midline-extraventricular, 3) off-midline-intraventricular, and 4) off-midline-extraventricular, which represent a continuum.
Wingless-type-subgroup medulloblastomas are lateralized tumors arising from the brain stem and cerebellum around the foramen of Luschka. Our current understanding of their embryologic origins is in concordance with the spatial distribution of these tumors.
Abstract Purpose Continuity of care is considered a core element of high-quality primary care, but its impact on mortality and health care costs is unclear. We aimed to determine the impact of ...continuity of care on mortality, costs, and health outcomes in patients with newly diagnosed cardiovascular risk factors. Methods We conducted a cohort study of a 3% nationwide random sample of Korean National Health Insurance enrollees. A total of 47,433 patients who had received new diagnoses of hypertension, diabetes, hypercholesterolemia, or their complications in 2003 or 2004 were included. We determined standard indices of continuity of care—most frequent provider continuity (MFPC), modified, modified continuity index (MMCI), and continuity of care index (COC)—and evaluated their association with study outcomes over 5 years of follow-up. Outcome measures included overall mortality, cardiovascular mortality, incident cardiovascular events, and health care costs. Results The multivariable-adjusted hazard ratios (HRs) for all-cause mortality, cardiovascular mortality, incident myocardial infarction, and incident ischemic stroke comparing participants with COC index below the median to those above the median were HR = 1.12 (95% CI, 1.04–1.21), 1.30 (1.13–1.50), 1.57 (1.281.95), and 1.44 (1.27–1.63), respectively. Similar findings were obtained for other indices of continuity of care. Lower continuity of care was also associated with increased inpatient and outpatient days and costs. Conclusions Lower indices of continuity of care in patients with newly diagnosed hypertension, diabetes, and hypercholesterolemia were associated with higher all-cause and cardiovascular mortality, cardiovascular events, and health care costs. Health care systems should be designed to support long-term trusting relationships between patients and physicians.
Autoimmune pancreatitis (AIP) is a peculiar type of chronic pancreatitis that responds dramatically to steroid therapy. To date, there are no worldwide consensus criteria for AIP. Different criteria ...with institutional preference (HISORt, revised Kim and the revised Japanese criteria) are being used to diagnose AIP, and there is controversy regarding the inclusion of steroid responsiveness in the diagnostic criteria. In contrast to the HISORt and revised Kim criteria, the revised Japanese criteria do not include steroid responsiveness as a diagnostic component.
This study was performed to evaluate whether "a 2-week steroid trial and subsequent assessment of its response" is a useful diagnostic tool for the differentiation of AIP from pancreatic cancer. A further aim was to discover the surgical and clinical outcome for a patient who followed the treatment algorithm based on the steroid responsiveness.
From January 2004 to June 2007, in the setting of clinically suspected AIP, 22 consecutive patients with atypical imaging for AIP, while not meeting the classic imaging criteria for pancreatic cancer, were challenged to undergo 2 weeks of steroid therapy (0.5 mg/kg of oral prednisolone per day). After the 2-week steroid trial, steroid responsiveness was assessed based on a marked improvement of narrowing of the main pancreatic duct and a reduction of the pancreatic mass. The steroid trial was continued in the case of positive steroid responsiveness, whereas surgical exploration was conducted in the case of negative steroid responsiveness. The final diagnosis was made by surgical exploration or long-term clinical and radiological follow-up.
All patients (n = 15) who responded to steroids were diagnosed as having AIP, whereas all patients (n = 7) who did not show a response to steroids were confirmed as having pancreatic cancer. Complete resection was possible in all (6/6; 100%), except one individual who refused surgery.
In the clinical setting of suspected AIP with the continued need for differentiation from pancreatic cancer due to atypical imaging for AIP, "a 2-week steroid trial and subsequent assessment of its response" may be helpful in confirming the diagnosis of AIP without negative consequences for resectable pancreatic cancer. However, a steroid trial should be performed carefully only by specialists in pancreatology.
Background
In gallbladder cancer, stage T2 is subdivided by tumour location into lesions on the peritoneal side (T2a) or hepatic side (T2b). For tumours on the peritoneal side (T2a), it has been ...suggested that liver resection may be omitted without compromising the prognosis. However, data to validate this argument are lacking. This study aimed to investigate the prognostic value of tumour location in T2 gallbladder cancer, and to clarify the adequate extent of surgical resection.
Methods
Clinical data from patients who underwent surgery for gallbladder cancer were collected from 14 hospitals in Korea, Japan, Chile and the USA. Survival and risk factor analyses were conducted.
Results
Data from 937 patients were available for evaluation. The overall 5‐year disease‐free survival rate was 70·6 per cent, 74·5 per cent for those with T2a and 65·5 per cent among those with T2b tumours (P = 0·028). Regarding liver resection, extended cholecystectomy was associated with a better 5‐year disease‐free survival rate than simple cholecystectomy (73·0 versus 61·5 per cent; P = 0·012). The 5‐year disease‐free survival rate was marginally better for extended than simple cholecystectomy in both T2a (76·5 versus 66·1 per cent; P = 0·094) and T2b (68·2 versus 56·2 per cent; P = 0·084) disease. Five‐year disease‐free survival rates were similar for extended cholecystectomies including liver wedge resection versus segment IVb/V segmentectomy (74·1 versus 71·5 per cent; P = 0·720). In multivariable analysis, independent risk factors for recurrence were presence of symptoms (hazard ratio (HR) 1·52; P = 0·002), R1 resection (HR 1·96; P = 0·004) and N1/N2 status (N1: HR 3·40, P < 0·001; N2: HR 9·56, P < 0·001). Among recurrences, 70·8 per cent were metastatic.
Conclusion
Tumour location was not an independent prognostic factor in T2 gallbladder cancer. Extended cholecystectomy was marginally superior to simple cholecystectomy. A radical operation should include liver resection and adequate node dissection.
Antecedentes
En el cáncer de vesícula biliar, la ubicación del tumor subdivide el estadio T2 en tumores con invasión del lado peritoneal y del lado del hígado (T2a y T2b). Para los tumores que invaden el lado peritoneal (T2a) se sugiere que se puede obviar la resección hepática sin que ello comprometa el pronóstico. Sin embargo, este argumento no ha sido validado. El estudio tuvo como objetivo investigar el valor pronóstico de la localización del tumor en el cáncer de vesícula biliar T2 y establecer la extensión adecuada de la resección quirúrgica.
Métodos
Se recogieron los datos clínicos de pacientes que se sometieron a cirugía por cáncer de vesícula biliar en 14 hospitales de Corea, Japón, Chile y Estados Unidos. Se realizaron análisis de la supervivencia y de los factores de riesgo.
Resultados
Se dispuso de datos de 937 pacientes para ser evaluados. La tasa de supervivencia global libre de enfermedad a los 5 años fue del 70,6%, y las de T2a y T2b del 74,5% y 65,5% (P = 0,028). Con respecto a la resección hepática, la colecistectomía extendida presentó una tasa mejor de supervivencia libre de enfermedad a los 5 años que la colecistectomía simple (73,0% versus 61,5%, P = 0,012). La tasa de supervivencia libre de enfermedad a los 5 años fue marginalmente mejor para la colecistectomía extendida que para la colecistectomía simple tanto en T2a (76,5% versus 66,1%, P = 0,094) como en T2b (68,2% versus 56,2%, P = 0,084). Las tasas de supervivencia libre de enfermedad a los 5 años no fueron diferentes entre la resección hepática en cuña y la segmentectomía S4b+S5 (74,1% versus 71,5%, P = 0,720). En el análisis multivariable, los factores de riesgo independientes para la recidiva fueron la presencia de síntomas (cociente de riesgos instantáneos, hazard ratio, HR 1,52, P = 0,002), la resección R1 (HR 1,96, P = 0,004) y el estadio N1/N2 (N1 HR 3,40, P < 0,001; N2 HR 9,56, P < 0,001). El 70,8% de las recidivas eran metastásicas.
Conclusión
La localización del tumor no fue un factor pronóstico independiente en el cáncer de vesícula biliar T2. La colecistectomía extendida fue marginalmente superior que la colecistectomía simple. La cirugía radical debe incluir una resección hepática y una linfadenectomía adecuada.
This multinational multicentre cohort study was undertaken to investigate the prognostic value of tumour location in T2 gallbladder cancer and to clarify the adequate extent of surgical resection. Although tumour location influenced prognosis, it was not an independent prognostic factor in T2 gallbladder cancer. T2 gallbladder cancer requires extended cholecystectomy including hepatic resection and lymph node dissection, regardless of the location.
challenges current TNM system
Most current models for predicting survival after resection of colorectal liver metastasis include largest diameter and number of colorectal liver metastases as dichotomous variables, resulting in ...underestimation of the extent of risk variation and substantial loss of statistical power. The aim of this study was to develop and validate a new prognostic model for patients undergoing liver resection including largest diameter and number of colorectal liver metastases as continuous variables.
A prognostic model was developed using data from patients who underwent liver resection for colorectal liver metastases at MD Anderson Cancer Center and had RAS mutational data. A Cox proportional hazards model analysis was used to develop a model based on largest colorectal liver metastasis diameter and number of metastases as continuous variables. The model results were shown using contour plots, and validated externally in an international multi-institutional cohort.
A total of 810 patients met the inclusion criteria. Largest colorectal liver metastasis diameter (hazard ratio (HR) 1.11, 95 per cent confidence interval 1.06 to 1.16; P < 0.001), number of colorectal liver metastases (HR 1.06, 1.03 to 1.09; P < 0.001), and RAS mutation status (HR 1.76, 1.42 to 2.18; P < 0.001) were significantly associated with overall survival, together with age, primary lymph node metastasis, and prehepatectomy chemotherapy. The model performed well in the external validation cohort, with predicted overall survival values almost lying within 10 per cent of observed values. Wild-type RAS was associated with better overall survival than RAS mutation even when liver resection was performed for larger and/or multiple colorectal liver metastases.
The contour prognostic model, based on diameter and number of lesions considered as continuous variables along with RAS mutation, predicts overall survival after resection of colorectal liver metastasis.
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