Very Long-term Outcome of Bilateral Internal Thoracic Artery in Diabetic Patients: A Systematic Review and Reconstructed Time-To-Event Meta-analysis

The benefits of single (SITA) and bilateral internal thoracic arteries (BITA) in diabetics undergoing coronary bypass grafting (CABG) are conflicting. We undertook a study-level meta-analysis to compare early and long-term outcomes of both CABG configurations. PubMed, CENTRAL, and EMBASE were searched for studies comparing BITA versus SITA for isolated CABG surgery in diabetics. Randomized trials or observational studies were considered eligible for the analysis. Kaplan-Meier curves of long-term survival were reconstructed and compared with Cox linear regression; incidence rate ratios (IRR) with 95% confidence intervals (CI) for long-term survival were calculated. Landmark analysis and time-varying hazard ratio (HR) were analyzed. Odds ratios (OR) were extracted for early mortality, postoperative stroke, deep sternal wound infection (DSWI), and myocardial infarction (MI). A random effects meta-analysis was performed. Sensitivity analyses included leave-one-out-analyses and meta-regression. Thirteen studies (7332 patients) were included. Overall, at 20-year follow-up, BITA was associated with higher survival (HR = 0.77; 95% CI, 0.71-0.84; P < 0.0001). Time-varying HR and landmark analysis reported BITA was associated with a higher rate of 10-year survival (HR = 0.75, 95% CI 0.68-0.82, P < 0.0001), while from 10 to 20-year follow-up no difference was revealed (HR = 0.99, 95% CI 0.82-1.19, P = 0.93). There was no increase in early mortality, postoperative MI, stroke, or DSWI between the groups. At meta-regression, the higher the age, the higher the long-term overall survival in patients with BITA. In diabetics, the BITA approach is associated with improved 10-year survival with no increase in early mortality, MI, stroke, or DSWI. In the 10-20-year timeframe, BITA and SITA showed comparable survival.

Extracorporeal life support in mitral papillary muscle rupture: Outcome of multicenter study

BACKGROUND

Post-acute myocardial infarction papillary muscle rupture (post-AMI PMR) may present variable clinical scenarios and degree of emergency due to result of cardiogenic shock. Veno-arterial extracorporeal life support (V-A ECLS) has been proposed to improve extremely poor pre- or postoperative conditions. Information in this respect is scarce.

METHODS

From the CAUTION (meChanical complicAtion of acUte myocardial infarcTion: an InternatiOnal multiceNter cohort study) database (16 different Centers, data from 2001 to 2018), we extracted adult patients who were surgically treated for post-AMI PMR and underwent pre- or/and postoperative V-A ECLS support. The end-points of this study were in-hospital survival and ECLS complications.

RESULTS

From a total of 214 post-AMI PMR patients submitted to surgery, V-A ECLS was instituted in 23 (11%) patients. The median age was 61.7 years (range 46-81 years). Preoperatively, ECLS was commenced in 10 patients (43.5%), whereas intra/postoperative in the remaining 13. The most common V-A ECLS indication was post-cardiotomy shock, followed by preoperative cardiogenic shock and cardiac arrest. The median duration of V-A ECLS was 4 days. V-A ECLS complications occurred in more than half of the patients. Overall, in-hospital mortality was 39.2% (9/23), compared to 22% (42/219) for the non-ECLS group.

CONCLUSIONS

In post-AMI PMR patients, V-A ECLS was used in almost 10% of the patients either to promote bridge to surgery or as postoperative support. Further investigations are required to better evaluate a potential for increased use and its effects of V-A ECLS in such a context based on the still high perioperative mortality.

Iron-sulfur complex assembly: Potential players of magnetic induction in plants

Iron-sulfur (Fe-S) clusters are involved in fundamental biological reactions and represent a highly regulated process involving a complex sequence of mitochondrial, cytosolic and nuclear-catalyzed protein-protein interactions. Iron-sulfur complex assembly (ISCA) scaffold proteins are involved in Fe-S cluster biosynthesis, nitrogen and sulfur metabolism. ISCA proteins are involved in abiotic stress responses and in the pigeon they act as a magnetic sensor by forming a magnetosensor (MagS) complex with cryptochrome (Cry). MagR gene exists in the genomes of humans, plants, and microorganisms and the interaction between Cry and MagR is highly conserved. Owing to the extensive presence of ISCA proteins in plants and the occurrence of homology between animal and human MagR with at least four Arabidopsis ISCAs and several ISCAs from different plant species, we believe that a mechanism similar to pigeon magnetoperception might be present in plants. We suggest that plant ISCA proteins, homologous of the animal MagR, are good candidates and could contribute to a better understanding of plant magnetic induction. We thus urge more studies in this regard to fully uncover the plant molecular mechanisms underlying MagR/Cry mediated magnetic induction and the possible coupling between light and magnetic induction.

MoBiFC: development of a modular bimolecular fluorescence complementation toolkit for the analysis of chloroplast protein-protein interactions

BACKGROUND

The bimolecular fluorescence complementation (BiFC) assay has emerged as one of the most popular methods for analysing protein-protein interactions (PPIs) in plant biology. This includes its increasing use as a tool for dissecting the molecular mechanisms of chloroplast function. However, the construction of chloroplast fusion proteins for BiFC can be difficult, and the availability and selection of appropriate controls is not trivial. Furthermore, the challenges of performing BiFC in restricted cellular compartments has not been specifically addressed.

RESULTS

Here we describe the development of a flexible modular cloning-based toolkit for BiFC (MoBiFC) and proximity labelling in the chloroplast and other cellular compartments using synthetic biology principles. We used pairs of chloroplast proteins previously shown to interact (HSP21/HSP21 and HSP21/PTAC5) and a negative control (HSP21/ΔPTAC5) to develop standardised Goldengate-compatible modules for the assembly of protein fusions with fluorescent protein (FP) fragments for BiFC expressed from a single multigenic T-DNA. Using synthetic biology principles and transient expression in Nicotiana benthamiana, we iteratively improved the approach by testing different FP fragments, promoters, reference FPs for ratiometric quantification, and cell types. A generic negative control (mCHERRY) was also tested, and modules for the identification of proximal proteins by Turbo-ID labelling were developed and validated.

CONCLUSIONS

MoBiFC facilitates the cloning process for organelle-targeted proteins, allows robust ratiometric quantification, and makes available model positive and negative controls. Development of MoBiFC underlines how Goldengate cloning approaches accelerate the development and enrichment of new toolsets, and highlights several potential pitfalls in designing BiFC experiments including the choice of FP split, negative controls, cell type, and reference FP. We discuss how MoBiFC could be further improved and extended to other compartments of the plant cell and to high throughput cloning approaches.

The early and long-term outcomes of coronary artery bypass grafting added to aortic valve replacement compared to isolated aortic valve replacement in elderly patients: a systematic review and meta-analysis

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.

A guanosine tetraphosphate (ppGpp) mediated brake on photosynthesis is required for acclimation to nitrogen limitation in Arabidopsis

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 remobilisation, 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 Arabidopsis. 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.

Surgical treatment for post-infarction papillary muscle rupture: a multicentre study

OBJECTIVES

Papillary muscle rupture (PMR) is a rare but potentially fatal complication of acute myocardial infarction. The aim of this study was to analyse the patient characteristics and early outcomes of the surgical management of post-infarction PMR from an international multicentre registry.

METHODS

Patients underwent surgery for post-infarction PMR between 2001 through 2019 were retrieved from database of the CAUTION study. The primary end point was in-hospital mortality.

RESULTS

A total of 214 patients were included with a mean age of 66.9 (standard deviation: 10.5) years. The posteromedial papillary muscle was the most frequent rupture location (71.9%); the rupture was complete in 67.3% of patients. Mitral valve replacement was performed in 82.7% of cases. One hundred twenty-two patients (57%) had concomitant coronary artery bypass grafting. In-hospital mortality was 24.8%. Temporal trends revealed no apparent improvement in in-hospital mortality during the study period. Multivariable analysis showed that preoperative chronic kidney disfunction [odds ratio (OR): 2.62, 95% confidence interval (CI): 1.07-6.45, P = 0.036], cardiac arrest (OR: 3.99, 95% CI: 1.02-15.61, P = 0.046) and cardiopulmonary bypass duration (OR: 1.01, 95% CI: 1.00-1.02, P = 0.04) were independently associated with an increased risk of in-hospital death, whereas concomitant coronary artery bypass grafting was identified as an independent predictor of early survival (OR: 0.38, 95% CI: 0.16-0.92, P = 0.031).

CONCLUSIONS

Surgical treatment for post-infarction PMR carries a high in-hospital mortality rate, which did not improve during the study period. Because concomitant coronary artery bypass grafting confers a survival benefit, this additional procedure should be performed, whenever possible, in an attempt to improve the outcome.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov: NCT03848429.

Survival effect of radial artery usage in addition to bilateral internal thoracic arterial grafting: A meta-analysis

OBJECTIVE

Little evidence shows whether the radial artery (RA) as third arterial graft provides superior outcomes compared with the use of the bilateral internal thoracic artery (BITA) and saphenous vein (SV) graft in patients undergoing coronary artery bypass grafting. A meta-analysis of propensity score-matched observational studies that compared the long-term outcomes of coronary artery bypass grafting with the use of BITA and the RA (BITA + RA) versus BITA and SV (BITA + SV) was performed.

METHODS

Electronic databases from January 2000 to November 2020 were screened. Studies that reported long-term mortality were analyzed. The primary outcome was long-term overall mortality. A secondary end point was in-hospital/30-day mortality. Pooled hazard ratio with 95% confidence interval (CI) were calculated for survival and time-to-event analysis according to a random effect model. Differences were expressed as odds ratio with 95% CI for in-hospital/30-day mortality.

RESULTS

Six propensity score-matched studies that reported on 2500 matched patients (BITA + RA: 1250; BITA + SV: 1250) were identified for comparison. The use of BITA + RA was not statistically associated with early mortality (odds ratio, 0.90; 95% CI, 0.36-2.28; P = .83). The mean follow-up time ranged from 7.5 to 12 years. The pooled analysis of long-term survival revealed a significant difference between the 2 groups favoring BITA + RA treatment (hazard ratio, 0.71; 95% CI, 0.50-0.91; P = .031). The survival rate for BITA + RA versus BITA + SV at 5, 10, and 15 years were: 96.2% versus 94.8%, 88.9% versus 87.4%, and 83% versus 77.9%, respectively (log rank test, P = .02).

CONCLUSIONS

In patients with coronary artery bypass grafting, BITA + RA usage is not associated with higher rates of operative risk and is associated with superior long-term overall survival.

Surgical Treatment of Post-Infarction Left Ventricular Free-Wall Rupture: A Multicenter Study

BACKGROUND

Left ventricular free-wall rupture (LVFWR) is an uncommon but serious mechanical complication of acute myocardial infarction. Surgical repair, though challenging, is the only definitive treatment. Given the rarity of this condition, however, results after surgery are still not well established. The aim of this study was to review a multicenter experience with the surgical management of post-infarction LVFWR and analyze the associated early outcomes.

METHODS

Using the CAUTION (Mechanical Complications of Acute Myocardial Infarction: an International Multicenter Cohort Study) database, we identified 140 patients who were surgically treated for post-acute myocardial infarction LVFWR in 15 different centers from 2001 to 2018. The main outcome measured was operative mortality. Multivariate analysis was carried out by constructing a logistic regression model to identify predictors of postoperative mortality.

RESULTS

The mean age of patients was 69.4 years. The oozing type of LVFWR was observed in 79 patients (56.4%), and the blowout type in 61 (43.6%). Sutured repair was used in the 61.4% of cases. The operative mortality rate was 36.4%. Low cardiac output syndrome was the main cause of perioperative death. Myocardial rerupture after surgery occurred in 10 patients (7.1%). Multivariable analysis revealed that preoperative left ventricular ejection fraction (P < .001), cardiac arrest at presentation (P = .011), female sex (P = .044), and the need for preoperative extracorporeal life support (P = .003) were independent predictors for operative mortality.

CONCLUSIONS

Surgical repair of post-infarction LVFWR carries a high operative mortality. Female sex, preoperative left ventricular ejection fraction, cardiac arrest, and extracorporeal life support are predictors of early mortality.

Tanned or Sunburned: How Excessive Light Triggers Plant Cell Death

Plants often encounter light intensities exceeding the capacity of photosynthesis (excessive light) mainly due to biotic and abiotic factors, which lower CO₂ fixation and reduce light energy sinks. Under excessive light, the photosynthetic electron transport chain generates damaging molecules, hence leading to photooxidative stress and eventually to cell death. In this review, we summarize the mechanisms linking the excessive absorption of light energy in chloroplasts to programmed cell death in plant leaves. We highlight the importance of reactive carbonyl species generated by lipid photooxidation, their detoxification, and the integrating role of the endoplasmic reticulum in the adoption of phototolerance or cell-death pathways. Finally, we invite the scientific community to standardize the conditions of excessive light treatments.

Endoplasmic reticulum-mediated unfolded protein response is an integral part of singlet oxygen signalling in plants

Singlet oxygen (¹ O₂ ) is a by-product of photosynthesis that triggers a signalling pathway leading to stress acclimation or to cell death. By analyzing gene expressions in a ¹ O₂ -overproducing Arabidopsis mutant (ch1) under different light regimes, we show here that the ¹ O₂ signalling pathway involves the endoplasmic reticulum (ER)-mediated unfolded protein response (UPR). ch1 plants in low light exhibited a moderate activation of UPR genes, in particular bZIP60, and low concentrations of the UPR-inducer tunicamycin enhanced tolerance to photooxidative stress, together suggesting a role for UPR in plant acclimation to low ¹ O₂ levels. Exposure of ch1 to high light stress ultimately leading to cell death resulted in a marked upregulation of the two UPR branches (bZIP60/IRE1 and bZIP28/bZIP17). Accordingly, mutational suppression of bZIP60 and bZIP28 increased plant phototolerance, and a strong UPR activation by high tunicamycin concentrations promoted high light-induced cell death. Conversely, light acclimation of ch1 to ¹ O₂ stress put a limitation in the high light-induced expression of UPR genes, except for the gene encoding the BIP3 chaperone, which was selectively upregulated. BIP3 deletion enhanced Arabidopsis photosensitivity while plants treated with a chemical chaperone exhibited enhanced phototolerance. In conclusion, ¹ O₂ induces the ER-mediated UPR response that fulfils a dual role in high light stress: a moderate UPR, with selective induction of BIP3, is part of the acclimatory response to ¹ O₂ , and a strong activation of the whole UPR is associated with cell death.

Total arterial coronary myocardial revascularization with internal thoracic arteries to the left coronary system and radial artery to the right coronary artery

Total arterial myocardial revascularization is still an uncommon surgical procedure and long-term survival benefits of revascularization with the radial artery in addition to bilateral internal thoracic arteries, have not been clearly defined.  In this video tutorial we present the case of a 63-year-old male with 3-vessel coronary artery disease, who underwent total arterial revascularization coronary artery bypass grafting with skeletonized Y-graft bilateral internal thoracic arteries to the left coronary system and the radial artery to the descending posterior artery. The postoperative course was uneventful and the patient was discharged on the 5th postoperative day. In selected patients, younger than 65 years old, with 3-vessel coronary artery disease, total arterial myocardial revascularization with the radial artery and bilateral internal thoracic arteries is safe, reproducible, and may confer excellent long-term results.

The Apocarotenoid β-Cyclocitric Acid Elicits Drought Tolerance in Plants

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.

Sensing β-carotene oxidation in photosystem II to master plant stress tolerance

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 (¹ O₂ ), 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 ¹ O₂ 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.

OXI1 and DAD Regulate Light-Induced Cell Death Antagonistically through Jasmonate and Salicylate Levels

Singlet oxygen produced from triplet excited chlorophylls in photosynthesis is a signal molecule that can induce programmed cell death (PCD) through the action of the OXIDATIVE STRESS INDUCIBLE 1 (OXI1) kinase. Here, we identify two negative regulators of light-induced PCD that modulate OXI1 expression: DAD1 and DAD2, homologs of the human antiapoptotic protein DEFENDER AGAINST CELL DEATH. Overexpressing OXI1 in Arabidopsis (Arabidopsis thaliana) increased plant sensitivity to high light and induced early senescence of mature leaves. Both phenomena rely on a marked accumulation of jasmonate and salicylate. DAD1 or DAD2 overexpression decreased OXI1 expression, jasmonate levels, and sensitivity to photooxidative stress. Knock-out mutants of DAD1 or DAD2 exhibited the opposite responses. Exogenous applications of jasmonate upregulated salicylate biosynthesis genes and caused leaf damage in wild-type plants but not in the salicylate biosynthesis mutant Salicylic acid induction-deficient2, indicating that salicylate plays a crucial role in PCD downstream of jasmonate. Treating plants with salicylate upregulated the DAD genes and downregulated OXI1 We conclude that OXI1 and DAD are antagonistic regulators of cell death through modulating jasmonate and salicylate levels. High light-induced PCD thus results from a tight control of the relative activities of these regulating proteins, with DAD exerting a negative feedback control on OXI1 expression.

The impact of the radial artery or the saphenous vein in addition to the bilateral internal mammary arteries on late survival: A propensity score analysis

BACKGROUND

Long-term survival benefits of full arterial revascularization with radial artery (RA) used in addition to bilateral internal mammary arteries (BIMA) compared with saphenous vein (SV) used in addition to BIMA has not been clearly defined.

METHODS

We retrospectively analyzed 660 3-vessel coronary artery disease subjects who received BIMA in addition to either RA (n = 206) or SV (n = 454) grafting in a period between June 1999 and November 2017. After propensity score matching, we obtained 190 matched pairs for analysis.

RESULTS

In the matched population, in-hospital mortality occurred in 4 patients (1%), with 2 deaths (1.1%) in the BIMA + RA group and 2 deaths (1.1%) in BIMA + SV group (P > .99). The median follow-up time was 9.2 years (interquartile range, 5.6-13 years) with a maximum follow-up time of 18.5 years. There was not a significant difference in long-term survival between the 2 groups over the follow-up period. Survival at 5, 10, and 15 years were 94.8 ± 1.7%, 83.7 ± 3.1%, and 78.6 ± 3.9% in the BIMA + RA group and 96.2 ± 1.4%, 85.1 ± 2.9%, and 80.4 ± 3.6% in the BIMA + SV group (stratified log-rank P = .78). Cox proportional hazard regression model was used to estimate that the use of RA in addition to BIMA did not affect the late mortality (propensity score adjusted hazard ratio, 1.05; 95% confidence interval, 0.62-1.79; P = .83).

CONCLUSIONS

In a relatively small population of triple-vessel coronary artery disease, the use of RA as a third arterial conduit with BIMA did not confer a long-term survival benefit.

Decoding β-Cyclocitral-Mediated Retrograde Signaling Reveals the Role of a Detoxification Response in Plant Tolerance to Photooxidative Stress

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-cyclocitral-inducible 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.

METHYLENE BLUE SENSITIVITY 1 (MBS1) is required for acclimation of Arabidopsis to singlet oxygen and acts downstream of β-cyclocitral

Singlet oxygen (¹ O₂ ) signalling in plants is essential to trigger both acclimatory mechanisms and programmed cell death under high light stress. However, because of its chemical features, ¹ O₂ requires mediators, and the players involved in this pathway are largely unknown. The β-carotene oxidation product, β-cyclocitral, is one such mediator. Produced in the chloroplast, β-cyclocitral induces changes in nuclear gene expression leading to photoacclimation. Recently, the METHYLENE BLUE SENSITIVITY protein MBS has been identified as a key player in ¹ O₂ signalling leading to tolerance to high light. Here, we provide evidence that MBS1 is essential for acclimation to ¹ O₂ and cross-talks with β-cyclocitral to mediate transfer of the ¹ O₂ signal to the nucleus, leading to photoacclimation. The presented results position MBS1 downstream of β-cyclocitral in ¹ O₂ signalling and suggest an additional role for MBS1 in the regulation of plant growth and development under chronic ¹ O₂ production.

The co-chaperone p23 controls root development through the modulation of auxin distribution in the Arabidopsis root meristem

Homologues of the p23 co-chaperone of HSP90 are present in all eukaryotes, suggesting conserved functions for this protein throughout evolution. Although p23 has been extensively studied in animal systems, little is known about its function in plants. In the present study, the functional characterization of the two isoforms of p23 in Arabidopsis thaliana is reported, suggesting a key role of p23 in the regulation of root development. Arabidopsis p23 mutants, for either form, show a short root length phenotype with a reduced meristem length. In the root meristem a low auxin level associated with a smaller auxin gradient was observed. A decrease in the expression levels of PIN FORMED PROTEIN (PIN)1, PIN3, and PIN7, contextually to an inefficient polar localization of PIN1, was detected. Collectively these results suggest that both Arabidopsis p23 isoforms are required for root growth, in particular in the maintenance of the root meristem, where the proteins are located.

Re-creation of a sinuslike graft expansion in Bentall procedure reduces stress at the coronary button anastomoses: A finite element study

OBJECTIVE

The Bentall procedure is routinely performed using a straight Dacron graft coupled with a mechanical or a biologic valve. Creation of coronary ostia buttons significantly reduces tension on the coronary anastomoses and consequently the incidence of pseudoaneurysm formation. We sought to evaluate if the use of a specifically designed graft with a sinuslike root portion that bulges out upon pressurization can reduce stress on coronary anastomoses. A finite element computer-assisted stress analysis was used to simulate these 2 different anatomic conditions and to analyze tension in computed tomographic scans obtained from patients operated on with either a straight or a "sinus" graft.

METHODS

Theoretical models of the procedures with finite element computer-aided design technique were created and tested with the Abaqus Standard Suite, verifying the pattern of stress and strain when a uniform pressure of 200 mm Hg was applied to the model. Next, using SimpleWare SCanIP technology, computed tomographic scans of patients having both procedures were used to obtain finite element mesh models. A uniform pressure of 200 mm Hg was then applied, and the distribution of stress and strain was analyzed.

RESULTS

Von Mises Charts are color-coded, computational, 3-dimensional stress-pattern graphics that show that stress around the coronary ostia in a standard straight graft model is nearly double compared with the model with sinuses (peak stress of 0.4 Mpa for the sinus model and 0.7 Mpa for the traditional straight model). In computed tomographic scan reconstructions, the stress contour is uniformly distributed in the graft with sinuses, and it is highly concentrated around the ostia in the straight graft. Accordingly, higher-peak stress values are registered in the straight configuration (1.8 MPa for the sinus graft and 2.5 MPa for standard graft).

CONCLUSION

Even though finite elements technique is necessarily a simplification of a real biologic environment, all tests seem to indicate that a standard tubular graft gives a higher stress to coronary sutures. Relieving the stress on the coronary anastomoses by using a graft with preformed sinuses of Valsalva may decrease the incidence of postoperative complications such as bleeding and late pseudoaneurysm formation.

Old and new targets for innovative antimalarial compounds: the different strategies of the Italian Malaria Network

Clinical treatment-failures to affordable drugs encouraged new investigation for discovery and development of new prophylactic and therapeutic interventions against malaria. The Drug Discovery Cluster (DDcl) of the Italian Malaria Network gathers several highly integrated and complementary laboratories from different Italian Institutions to identify, synthesise, screen in vitro and in vivo new antimalarial molecules directed against the intraerythrocytic stage of P. falciparum parasites and/or with transmission blocking activity to select lead compounds for further development. Complementary research activities, both in vitro and in the clinics, aim at investigating the pathogenetic mechanisms of severe malaria anaemia and the different manifestations of the disease in malaria-HIV co-infected patients to identify new therapies and improve survival.

Sex differentiation pattern in the annual fish Austrolebias charrua (Cyprinodontiformes: Rivulidae)

Sex differentiation process, determination of sexual strategy, and gametogenesis of the annual fish Austrolebias charrua are established. Evidence of histological sex differentiation in an antero-posterior gradient was observed in pre-hatching stages. Sexual strategy corresponds to the "differentiated gonochoric" pattern. Histological analyses of adult gonads showed an asynchronous spawning mode for females and continuous spawning for males. Mature oocytes presented fluid yolk. Testis organization corresponded to a restricted spermatogonial model. Herein, we report the ultrastructural organization of the vitelline envelope and the main features of the sperm of A. charrua. Taking together these results also contribute to phylogenetic studies and provide base line data to propose A. charrua as a biomonitor of contamination in a protected area.

Effect of diabetes on early and late survival after isolated first coronary bypass surgery in multivessel disease

OBJECTIVE

Diabetes has not yet been investigated as a risk factor for early and late cardiac-related death.

METHODS

Patients operated on from January 1988 to December 1999 were considered; 767 were diabetic (group D) and 2593 were nondiabetic (group ND). Patients with preoperative hemodynamic deterioration were excluded. Early (30-day) mortality (any causes and cardiac causes) was evaluated with univariate analysis and stepwise logistic regression. Ten-year actuarial freedom from death of any cause and cardiac death was also assessed with univariate and Cox analyses.

RESULTS

Early mortality was 2.2% (group D, 3.3%; group ND, 1.9%; P =.023). Early cardiac mortality was 1.3% (group D, 2.2%; group ND, 1.1%; P =.0016). Diabetes was an independent risk factor only for cardiac death and not for death of any cause. Five-year survival was 93.5% +/- 0.5% (group D, 92.5% +/- 1.1%; group ND, 93.9% +/- 0.6%; P =.0304). Diabetes was not an independent risk factor. Five-year freedom for cardiac death was 96.3% +/- 0.4% (group D, 94.9% +/- 0.9%; group ND, 96.6% +/- 0.4%; P =.0155). Diabetes was an independent risk factor. However, if only the patients who survived the first 30 days are considered, diabetes disappears as a risk factor (5-year freedom for cardiac death, 97.8% +/- 0.3%; group D, 97.3% +/- 0.8%; group ND, 97.9% +/- 0.4%; P = 0.2389).

CONCLUSIONS

Diabetes is an independent risk factor for early cardiac death only. Long-term survival in patients who survive the first 30 days is not statistically significantly different for diabetic and nondiabetic patients. In fact, the rates appear very similar.

Revascularization of the lateral wall: long-term angiographic and clinical results of radial artery versus right internal thoracic artery grafting

OBJECTIVE

We sought to evaluate whether the radial artery provides the same results as the right internal thoracic artery in lateral wall revascularization in the long term.

METHODS

From January 1992 to September 1996, 288 patients had myocardial revascularization with the left internal thoracic artery anastomosed to the left anterior descending coronary artery. The lateral wall was grafted with the radial artery in 139 patients (group A) and with the right internal thoracic artery in 149 patients (group B). Groups were different only because of older age and a higher incidence of patients requiring urgent treatment in group A. Y grafting was used in 86.4% of patients in group A and in 34.8% of patients in group B (P < .001). Anastomoses per patient were similar in both groups (3.2 +/- 0.8 vs 3.2 +/- 0.9, P = 1.000).

RESULTS

Thirty-day mortality was similar (2.1% vs 2.0%, P = .722). There were 15 late deaths in group A versus 11 in group B (P = .418). Cause of death was cardiac related in 6 patients in group A versus 7 in group B. Late redo or percutaneous transluminal coronary angioplasty was performed in 3 patients in group A and in 1 patient in group B (P = 0.538). Eight-year survival was 86.7% +/- 2.9% in group A versus 89.6% +/- 2.8% in group B (P = .477); event-free survival was 84.2% +/- 3.2% versus 88.9% +/- 2.9%, respectively (P = .430). The patency rate within 30 days was 99.1% in group A (105/106 left internal thoracic artery plus radial artery anastomoses) versus 100% in group B (52/52 bilateral internal thoracic artery anastomoses; P = .715). After a mean of 35 +/- 28 months, the patency rate was 99.0% in group A (100/101 left internal thoracic artery plus radial artery anastomoses) and 100% in group B (33/33 bilateral internal thoracic artery anastomoses, P = .560).

CONCLUSION

In the long-term, lateral wall grafting with the radial artery provides the same clinical and angiographic results as right internal thoracic artery grafting.

Composite lengthened arterial conduits: long-term angiographic results of an uncommon surgical strategy

BACKGROUND

We sought to evaluate the long-term patency rate of composite lengthened conduits.

METHODS AND RESULTS

From December 1991 to April 2000, 43 patients had a composite lengthened arterial conduit. There was a mean of 2.83 +/- 1.23 anastomoses per patient. No 30-day mortality occurred. Five patients died from 3 to 84 months after the operation (mean, 38.6 +/- 34.6 months). After a mean follow-up of 57.0 +/- 32.3 months (range, 3-99 months), all the survivors are asymptomatic. The only cardiac major events recorded were 2 (4.6%) late acute myocardial infarctions in the patients who died. Eight-year survival and event-free survival were both 80.4% +/- 9.1% (range, 3%-93%). In the early period (13.5 +/- 4.8 days) in 26 patients, 26 arterial composite lengthened conduits and 37 distal anastomoses had postoperative angiographic control; all the anastomoses were rates as grade A, according to Fitzgibbon classification. In the late period (29 +/- 30 months) in 23 patients, 23 arterial composite lengthened conduits and 34 distal anastomoses were checked; the patency rate was 22 (95.6%) of 23 for the composite lengthened conduits and 33 (97%) of 34 for the distal anastomoses.

CONCLUSIONS

In particular situations, when the length of an arterial conduit is not enough to allow a correct use of the graft, lengthening of an arterial conduit can be a safe and effective technique.