Stressful environmental conditions lead to the production of reactive oxygen species in the chloroplasts, due to limited photosynthesis and enhanced excitation pressure on the photosystems. Among ...these reactive species, singlet oxygen (¹O₂), which is generated at the level of the PSII reaction center, is very reactive, readily oxidizing macromolecules in its immediate surroundings, and it has been identified as the principal cause of photooxidative damage in plant leaves. The two β-carotene molecules present in the PSII reaction center are prime targets of ¹O₂ oxidation, leading to the formation of various oxidized derivatives. Plants have evolved sensing mechanisms for those PSII-generated metabolites, which regulate gene expression, putting in place defense mechanisms and alleviating the effects of PSII-damaging conditions. A new picture is thus emerging which places PSII as a sensor and transducer in plant stress resilience through its capacity to generate signaling metabolites under excess light energy. This review summarizes new advances in the characterization of the apocarotenoids involved in the PSII-mediated stress response and of the pathways elicited by these molecules, among which is the xenobiotic detoxification.
Left ventricular free wall rupture (LVFWR) is a catastrophic complication following acute myocardial infarction with an estimated incidence of 0.2-7.6% and mortality can be as high as 60%. This study ...aimed to identify the risk factors for morbidity and mortality in patients affected by LVFWR.
This is a retrospective study of 35 patients who underwent surgery for LVFWR between January 2000 and December 2016 at our institution.
The mean age of patients was 68.3 years. The in-hospital survival was 65.7% (n = 23), and 13% of survived patients presented with cardiac arrest. The following characteristics were associated with in-hospital mortality at univariable analysis: pre-existing hypertension (P = 0.02), need for inotropes (P = 0.02) and cardiac arrest (P < 0.0001) at presentation, cardiopulmonary resuscitation (P = 0.004), preoperative extracorporeal membrane oxygenation (P = 0.004), technique of LVFWR repair (P = 0.013), operation on extracorporeal membrane oxygenation (P = 0.005) and postoperative extracorporeal membrane oxygenation (P = 0.001). In the multivariable analysis, cardiac arrest at presentation was an independent predictor of in-hospital mortality (odds ratio 11.7, 95% confidence interval 2.352-59.063; P = 0.003). The overall mean postoperative follow-up was 8.3 ± 1.3 years. Overall survival rates at 5 and 10 years were 53.2 ± 8.6% and 49.1 ± 8.9%, respectively. Among the survivors, only 6 (26.1%) patients died during follow-up with a 5-year and 10-year overall survival rate of 80.9 ± 8.7% and 74.7 ± 10%, respectively.
These data suggest a trend towards long-term benefit in patients surviving high-risk surgery for LVFWR repair. Considering the high lethality of LVFWR, the urgency and complexity of the primary surgical intervention early diagnosis and prompt surgery play a key role in the management of this complication.
β-Cyclocitral (β-CC) is a volatile compound deriving from 1O2 oxidation of β-carotene in plant leaves. β-CC elicits a retrograde signal, modulating 1O2-responsive genes and enhancing tolerance to ...photooxidative stress. Here, we show that β-CC is converted into water-soluble β-cyclocitric acid (β-CCA) in leaves. This metabolite is a signal that enhances plant tolerance to drought by a mechanism different from known responses such as stomatal closure, osmotic potential adjustment, and jasmonate signaling. This action of β-CCA is a conserved mechanism, being observed in various plant species, and it does not fully overlap with the β-CC-dependent signaling, indicating that β-CCA induces only a branch of β-CC signaling. Overexpressing SCARECROW-LIKE14 (SCL14, a regulator of xenobiotic detoxification) increased drought tolerance and potentiated the protective effect of β-CCA, showing the involvement of the SCL14-dependent detoxification in the phenomenon. β-CCA is a bioactive apocarotenoid that could potentially be used to protect crop plants against drought.
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•β-Cyclocitral produced by 1O2 oxidation of β-carotene oxidizes to β-cyclocitric acid•β-Cyclocitric acid triggers a signaling cascade leading to drought tolerance•β-Cyclocitric acid is water soluble and offers perspectives in crop protection•The protective action of β-cyclocitric acid does not rely on stomatal closure
Biological Sciences; Plant Biology; Plant Genetics; Plant Physiology
In aged population, the early and long-term outcomes of coronary revascularization (CABG) added to surgical aortic valve replacement (SAVR) compared to isolated SAVR (i-SAVR) are conflicting. To ...address this limitation, a meta-analysis comparing the early and late outcomes of SAVR plus CABG with i-SAVR was performed. Electronic databases from January 2000 to November 2021 were screened. Studies reporting early-term and long-term comparison between the two treatments in patients over 75 years were analyzed. The primary endpoints were in-hospital/30-day mortality and overall long-term survival. The pooled odd ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) were calculated for in-early outcome and long-term survival, respectively. Random-effect model was used in all analyses. Forty-four retrospective observational studies reporting on 74,560 patients (i-SAVR = 36,062; SAVR + CABG = 38,498) were included for comparison. The pooled analysis revealed that i-SAVR was significantly associated with lower rate of early mortality compared to SAVR plus CABG (OR = 0.70, 95% CI 0.66–0.75;
p
< 0.0001) and with lower incidence of postoperative acute renal failure (OR = 0.65; 95% CI 0.50–0.91;
p
= 0.02), need for dialysis (OR = 0.65; 95% CI 0.50–0.86;
p
= 0.002) and prolonged mechanical ventilation (OR = 0.57; 95% CI 0.42–0.77;
p
< 0.0001). Twenty-two studies reported data of long-term follow-up. No differences were reported between the two groups in long-term survival (HR = 0.95; 95% CI 0.87–1.03;
p
= 0.23). CABG added to SAVR is associated with worse early outcomes in terms of early mortality, postoperative acute renal failure, and prolonged mechanical ventilation. Long-term survival was comparable between the two treatments.
Guanosine pentaphosphate and tetraphosphate (together referred to as ppGpp) are hyperphosphorylated nucleotides found in bacteria and the chloroplasts of plants and algae. In plants and algae ...artificial ppGpp accumulation can inhibit chloroplast gene expression, and influence photosynthesis, nutrient remobilization, growth, and immunity. However, it is so far unknown whether ppGpp is required for abiotic stress acclimation in plants. Here, we demonstrate that ppGpp biosynthesis is necessary for acclimation to nitrogen starvation in
. We show that ppGpp is required for remodeling the photosynthetic electron transport chain to downregulate photosynthetic activity and for protection against oxidative stress. Furthermore, we demonstrate that ppGpp is required for coupling chloroplastic and nuclear gene expression during nitrogen starvation. Altogether, our work indicates that ppGpp is a pivotal regulator of chloroplast activity for stress acclimation in plants.
Early and long-term outcomes in elderly patients who underwent isolated aortic valve replacement (iAVR) are well defined. Conflicting data exist in elderly patients who underwent AVR plus coronary ...artery bypass grafting (CABG). We sought to evaluate the early and long-term outcomes of combined AVR + CABG in patients older than 75 years of age. From June 1999 to June 2018, 402 patients ≥ 75 years who underwent iAVR (
n
= 200; 49.7%) or combined AVR plus CABG (
n
= 202; 50.3%) were retrospectively analysed. AVR + CABG patients were older than iAVR patients (78.5 ± 2.5 vs 77.6 ± 2.8 years;
p
< 0.0001), with greater co-morbidities and more urgent/emergency surgery. 30-day mortality was 6.5% in the AVR + CABG and 4.5% in the iAVR group (
p
= 0.38). Multivariate analysis identified EuroSCORE II odd ratio (OR) 1.13 postoperative stroke (OR 12.53), postoperative low cardiac output syndrome (OR 8.72) and postoperative mechanical ventilation > 48 h (OR 8.92) as independent predictors of 30-day mortality; preoperative cerebrovascular events (OR 3.43), creatinine (OR 7.27) and extracorporeal circulation time (OR 1.01) were independent predictors of in-hospital major adverse cardiovascular and cerebral events (MACCE). Treatment was not an independent predictor of 30-day mortality and in-hospital MACCE. Survival at 1, 5 and 10 years was 94.7 ± 1.6%, 72.6 ± 3.6% and 31.7 ± 4.8% for iAVR patients and 89.1 ± 2.3%, 73.9 ± 3.5% and 37.2 ± 4.8% for AVR + CABG subjects (
p
= 0.99). Using adjusted Cox regression model, creatinine hazard ration (HR) 1.50;
p
= 0.018, COPD (HR 1.97;
p
= 0.003) and NYHA class (HR 1.39;
p
< 0.0001) were independent predictors of late mortality; the combined AVR + CABG was not associated with increased risk of late mortality (HR 0.83;
p
= 0.30). In patients aged ≥ 75 years, combined AVR + CABG was not associated with increased 30-day mortality, in-hospital MACCE and long-term mortality. Surgical revascularization can be safely undertaken at the time of AVR in elderly patients.
When exposed to unfavorable environmental conditions, plants can absorb light energy in excess of their photosynthetic capacities, with the surplus energy leading to the production of reactive oxygen ...species and photooxidative stress. Subsequent lipid peroxidation generates toxic reactive carbonyl species whose accumulation culminates in cell death. β-Cyclocitral, an oxidized by-product of β-carotene generated in the chloroplasts, mediates a protective retrograde response that lowers the levels of toxic peroxides and carbonyls, limiting damage to intracellular components. In this study, we elucidate the molecular mechanism induced by β-cyclocitral in Arabidopsis thaliana and show that the xenobiotic detoxification response is involved in the tolerance to excess light energy. The involvement of the xenobiotic response suggests a possible origin for this pathway. Furthermore, we establish the hierarchical structure of this pathway that is mediated by the β-cyclocitralinducible GRAS protein SCARECROW LIKE14 (SCL14) and involves ANAC102 as a pivotal component upstream of other ANAC transcription factors and of many enzymes of the xenobiotic detoxification response. Finally, the SCL14-dependent protective mechanism is also involved in the low sensitivity of young leaf tissues to high-light stress.
Objective Human recombinant erythropoietin has been used to obtain a rapid increase in red blood cells before surgery. Previously, the shortest preparatory interval has been 4 days, but at the ...European Hospital only 2.4 days on average separate hospitalization and surgery. We therefore proposed a randomized blind trial to test the efficacy of high-dose erythropoietin for very short-term administration. Methods All patients presenting with a diagnosis of isolated coronary vessel disease were randomized to either erythropoietin therapy or a control group. Patients with a creatinine level greater than 2 mg/dL or hemoglobin level greater than 14.5 g/dL were excluded. Hemoglobin values were collected preoperatively and on postoperative days 1 and 4. Blood loss and blood transfusion rate were recorded at the time of discharge. Results We enrolled 320 consecutive patients in the study. No significant difference was found in preoperative parameters, postoperative blood loss, or mean preoperative hemoglobin levels. On postoperative day 4, mean hemoglobin was 15.5% higher in the erythropoietin group (10.70 ± 0.72 g/dL vs 9.26 ± 0.71 g/dL; P < .05). This group required 0.33 units of blood per patient, whereas the controls required 0.76 units per patient (risk ratio 0.43, P = .008). Conclusion A significant reduction in transfusion rate and a significant increase in hemoglobin values were observed in the erythropoietin group. No adverse events related to erythropoietin administration were recorded. A very short preoperative erythropoietin administration seems to be a safe and easy method to reduce the need for blood transfusions.
is a transcription factor involved in stress response and brassinosteroids signaling, with circadian regulation controlled by phytochromes.
has been proposed to have a role in downregulating ...chloroplast transcription, which may be very useful in reducing photosynthesis and chloroplast energy demand under stress conditions. However, its localization in the chloroplast has mainly been demonstrated by using constitutive promoters. In this work, we recapitulate the literature, clarify which are
isoforms in
and analyze their expressions under control conditions and in response to stress. Based on our results, the most highly expressed
isoform encodes for a nucleocytoplasmic protein and the N-terminal chloroplast-targeting peptide appears to be present only in Brassicaceae, and not involved in stress response.
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