53 research outputs found

    Soil penetration by maize roots is negatively related to ethylene-induced thickening

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    Radial expansion is a classic response of roots to a mechanical impedance that has generally been assumed to aid penetration. We analysed the response of maize nodal roots to impedance to test the hypothesis that radial expansion is not related to the ability of roots to cross a compacted soil layer. Genotypes varied in their ability to cross the compacted layer, and those with a steeper approach to the compacted layer or less radial expansion in the compacted layer were more likely to cross the layer and achieve greater depth. Root radial expansion was due to cortical cell size expansion, while cortical cell file number remained constant. Genotypes and nodal root classes that exhibited radial expansion in the compacted soil layer generally also thickened in response to exogenous ethylene in hydroponic culture, that is, radial expansion in response to ethylene was correlated with the thickening response to impedance in soil. We propose that ethylene insensitive roots, that is, those that do not thicken and can overcome impedance, have a competitive advantage under mechanically impeded conditions as they can maintain their elongation rates. We suggest that prolonged exposure to ethylene could function as a stop signal for axial root growth

    The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

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    AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

    Recent advances reveal IL-8 signaling as a potential key to targeting breast cancer stem cells

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    Breast cancer stem-like cells (CSCs) are an important therapeutic target as they are purported to be responsible for tumor initiation, maintenance, metastases, and disease recurrence. Interleukin-8 (IL-8) is upregulated in breast cancer compared with normal breast tissue and is associated with poor prognosis. IL-8 is reported to promote breast cancer progression by increasing cell invasion, angiogenesis, and metastases and is upregulated in HER2-positive cancers. Recently, we and others have established that IL-8 via its cognate receptors, CXCR1 and CXCR2, is also involved in regulating breast CSC activity. Our work demonstrates that in metastatic breast CSCs, CXCR1/2 signals via transactivation of HER2. Given the importance of HER2 in breast cancer and in regulating CSC activity, a pathway driving the activation of these receptors would have important biological and clinical consequences, especially in tumors that express high levels of IL-8 and other CXCR1/2-activating ligands. Here, we review the IL-8 signaling pathway and the role of HER2 in maintaining an IL-8 inflammatory loop and discuss the potential of combining CXCR1/2 inhibitors with other treatments such as HER2-targeted therapy as a novel approach to eliminate CSCs and improve patient survival

    Endoscopic biliary drainage for severe acute cholangitis in biliary obstruction as a result of malignant and benign diseases

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    Background and Aims: Endoscopic biliary drainage is an established mode of biliary decompression in patients with acute cholangitis as a result of biliary obstruction secondary to stones and benign strictures. However, there are no reports on endoscopic management of severe acute cholangitis caused by malignant conditions. We prospectively compared the efficacy of the endoscopic drainage for severe acute cholangitis in biliary obstruction as a result of malignant and benign diseases. Methods: Forty-three patients with severe acute cholangitis requiring urgent biliary drainage were included. Sixteen patients (mean age 58.2 &#177; 9.3 years; seven men, nine women) had biliary obstruction as a result of malignant diseases and 27 had benign biliary diseases (mean age 41.6 &#177; 14.3 years; nine men, 18 women). Indications for urgent drainage included any one of the following: temperature &gt;38&#176;C (n = 21), septic shock with systolic blood pressure &lt;100 mmHg (n = 9), localized peritonism (n = 21), impaired consciousness (n = 6) and failure to improve within 72 h of conservative management (n = 13). After successful bile duct cannulation, patients received either a nasobiliary catheter (n = 38) or an in-dwelling stent (n = 5) with or without sphincterotomy for biliary drainage. Outcome measures included complications and clinical response. Results: Endoscopic drainage was established successfully in all the patients in both the groups. Clinical improvement after biliary drainage occurred in 94% patients (15/16) in the malignant group compared with 96% patients (26/27) in the benign group (P = not significant [NS]). Fever subsided at a median of 2.2 days in the malignant group and at 1 day in the benign group (P = NS). Normalization of leukocyte count was seen at a median of 6 days (range 1-17) and 2 days (range 1-5) days in the malignant group and the the benign group, respectively (P = NS). There were no endoscopic retrograde cholangiopancreatography-related complications. The mortality rate as a result of cholangitis was 4.6%, that is two of 43 patients (6.2% of the malignant group vs 3.7% of the benign group; P = NS). Conclusions: Endoscopic biliary drainage is equally effective in patients with severe acute cholangitis caused by either malignant or benign biliary diseases

    Beneficial effects of antiviral therapy in advanced chronic liver disease due to HCV infection: a pilot study

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