Temporal σB stress-response profiles impact Bacillus subtilis fitness.

The Gram-positive model organism Bacillus subtilis responds to environmental stressors by activating the alternative sigma factor σB. The sensing apparatus upstream of σB activation is thought to consist of cytoplasmic stressosomes-megadalton-sized protein complexes that include five paralogous proteins known as RsbRs. The RsbRs are presumed to be involved in stress sensing and the subsequent response. Perturbations to the RsbR complement in stressosomes by engineering cells that produce only one of the RsbR paralogs ("single-RsbR strains") lead to altered σB response dynamics with respect to timing and magnitude. Here, we asked whether such changes to σB response dynamics impact the relative fitness of a strain. We competed strain pairs with different RsbR complements under ethanol and sodium chloride stress and found not only differences in relative fitness among wild-type and single-RsbR strains but also different relative fitness values in the two different stressors. We found that the presence of RsbRA, which dominates the wild-type σB response, enhances fitness in ethanol but is detrimental to fitness in NaCl. Meanwhile, RsbRD-only cells were among the most fit in NaCl. Strains producing hybrid RsbR fusion proteins displayed different fitness values that depended on the RsbR proteins from which they were derived. Our results here suggest that σB response dynamics can impact fitness, highlighting the physiological importance of the unusual stressosome-based general stress response system of B. subtilis. IMPORTANCE: The model bacterium Bacillus subtilis uses cytoplasmic multiprotein complexes, termed stressosomes, to activate the alternative sigma factor σB when facing environmental stresses. We have previously shown that genetically manipulating the complement of putative sensor proteins in stressosomes can alter the dynamics of the σB response in terms of its magnitude and timing. However, it is unknown whether these response dynamics impact the fitness of cells challenged by environmental stressors. Here, we examine the fitness of strains with different σB responses by competing strain pairs in exponential-phase co-cultures under environmental stress. We find that strains with different response dynamics show different competitive indices that differ by stressor. These results suggest that the dynamics of the σB response can affect the fitness of cells facing environmental stress, highlighting the relevance of different σB dynamics.

30-Day Outcomes With the Portico Transcatheter Heart Valve: Insights From a Multi-Centre Australian Observational Study.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an established therapy for the treatment of aortic valve disease in appropriately selected patients. Previous studies using the self-expanding Portico transcatheter heart valve (THV), (Abbott Structural Heart, St Paul, MN, USA) have demonstrated the technical feasibility of this system albeit in the hands of relatively inexperienced Portico users. The objective of this study was to assess the real-world safety and efficacy of the Portico THV (with and without the FlexNav delivery system, Abbott Structural Heart) at the 30-day timepoint in an Australian cohort. METHODS AND RESULTS: This study was a retrospective real-world cohort analysis of 269 consecutive patients with severe aortic valve disease who underwent TAVI at multiple centres within Australia between February 2015 and April 2021. Of the 269 patients, 51.7% were female, mean Society of Thoracic Surgeons (STS) score was 5.2 (±6.8) and 98.5% had successful implantations. Thirty (30)-day post-implantation all-cause mortality was observed in one (0.4%) patient, major vascular complications in two (0.7%) patients, more-than-mild paravalvular leak in six (2.2%) patients and requirement for new permanent pacemaker implantation in 27 (10.2%) patients. Haemodynamic parameters at 30 days included mean effective orifice area (EOA) of 2.3 (±0.9) cm2 and mean aortic valve gradient (AVG) of 9.6 (±6.2) mmHg. CONCLUSION: This analysis of the Portico THV in a real-world setting suggested that the system is associated with satisfactory safety and efficacy parameters. Previously published datasets may not have found similar findings owing to lower operator experience with the Portico THV system.

Intracardiac Leiomyomatosis - an Unusual Cause of Syncope in a Middle-Aged Woman.

Intracardiac leiomyomatosis is a rare complication that occurs when a uterine leiomyoma (fibroid) undergoes vascular invasion and propagates within the inferior vena cava to reach the right atrium. This article describes a case of intracardiac leiomyomatosis in a middle-aged woman, exploring the presentation, diagnosis and surgical management of this condition. In this case the presenting complaints were syncope and atrial fibrillation, illustrating the importance of performing a transthoracic echocardiogram in patients presenting with their first episode of atrial fibrillation. Clinicians should consider intracardiac leiomyomatosis when evaluating women with right heart masses, especially those with a history of uterine leiomyomas.

Long-term outcomes and factors influencing late survival following elective abdominal aortic aneurysm repair: A 24-year experience.

BACKGROUND: Abdominal aortic aneurysms can be either treated by an open abdominal aortic aneurysm repair or an endovascular repair. Comparing clinical predictors of outcomes and those which influence survival rates in the long term is important in determining the choice of treatment offered and the decision-making process with patients. AIMS: To determine the influence of pre-existing clinical predictors and perioperative determinants on late survival of elective open abdominal aortic aneurysm repair and endovascular repair at a tertiary hospital. METHODS: Consecutive patients undergoing elective abdominal aortic aneurysm repair from 1990 to 2013 were included. Data were collected from a prospectively acquired database and death data were gathered from the Queensland state death registry. Pre-existing risks and perioperative factors were assessed independently. Kaplan-Meier and Cox regression modeling were performed. RESULTS: During the study period, 1340 abdominal aortic aneurysms were repaired electively, of which 982 were open abdominal aortic aneurysm repair. The average age was 72.4 years old and 81.7% were males. The cumulative percentage survival rates for open abdominal aortic aneurysms repair at 5, 10, 15 and 20 years were 79, 49, 31 and 22, respectively. The corresponding 5-, 10- and 15-year survival rates for endovascular repair were not significantly different at 75, 49 and 33%, respectively (P = 0.75). Predictors of reduced survival were advanced age, American Society of Anaesthesiology scores, chronic obstructive pulmonary disease, renal impairment, bifurcated grafts, peripheral vascular disease and congestive heart failure. CONCLUSIONS: Open repair offers a good long-term treatment option for patients with an abdominal aortic aneurysm and in our experience there is no significant difference in late survival between open abdominal aortic aneurysms repair and endovascular repair. Consideration of the factors identified in this study that predict reduced long-term survival for open abdominal aortic aneurysms repair and endovascular repair should be considered when deciding repair of abdominal aortic aneurysm.

Aortocaval fistula: current management strategies.

BACKGROUND: There has been a trend towards favouring endovascular repair for much acute aortic pathology. We undertook a review of the literature to determine if an endovascular approach could complement the traditional treatment of aortocaval fistula (ACF), a rare complication of abdominal aortic aneurysm. METHODS: A literature search was undertaken on PubMed using appropriate search terms. Case series and reviews reporting presentation, diagnosis and operative management (open and endovascular techniques) of ACF were selected and discussed. RESULTS: Open surgical treatment of ACF has an associated morbidity and mortality - mainly from excessive blood loss. Open repair mortality rates are reported around 30%, but some centres report far lower rates based on preoperative diagnosis of the ACF. These rates appear to be reduced when using endovascular repair in selected cases, with success rates of up to 96%. Reiteration of the importance of diagnosis of ACF preoperatively was the common denominator with both open and endovascular repair. CONCLUSIONS: Endovascular exclusion appears to be an efficacious means of treating ACF and averting the significant blood loss commonly encountered in conventional repair of these lesions. However, some reviews have suggested equal success with open repair. There is limited available published literature on ACF management and outcome, and likely reporting bias attached to both open and endovascular results that are published. With a randomized controlled trial unlikely to occur, a prospective registry may provide better outcome data.

Predictors of outcome after elective endovascular abdominal aortic aneurysm repair and external validation of a risk prediction model.

INTRODUCTION: Endovascular abdominal aortic aneurysm (AAA) repair (EVAR) has been associated with lower operative mortality and morbidity than open surgery but comparable long-term mortality and higher delayed complication and reintervention rates. Attention has therefore been directed to identifying preoperative and operative variables that influence outcomes after EVAR. Risk-prediction models, such as the EVAR Risk Assessment (ERA) model, have also been developed to help surgeons plan EVAR procedures. The aims of this study were (1) to describe outcomes of elective EVAR at the Royal Brisbane and Women's Hospital (RBWH), (2) to identify preoperative and operative variables predictive of outcomes after EVAR, and (3) to externally validate the ERA model. METHODS: All elective EVAR procedures at the RBWH before July 1, 2009, were reviewed. Descriptive analyses were performed to determine the outcomes. Univariate and multivariate analyses were performed to identify preoperative and operative variables predictive of outcomes after EVAR. Binomial logistic regression analyses were used to externally validate the ERA model. RESULTS: Before July 1, 2009, 197 patients (172 men), who were a mean age of 72.8 years, underwent elective EVAR at the RBWH. Operative mortality was 1.0%. Survival was 81.1% at 3 years and 63.2% at 5 years. Multivariate analysis showed predictors of survival were age (P = .0126), American Society of Anesthesiologists (ASA) score (P = .0180), and chronic obstructive pulmonary disease (P = .0348) at 3 years and age (P = .0103), ASA score (P = .0006), renal failure (P = .0048), and serum creatinine (P = .0022) at 5 years. Aortic branch vessel score was predictive of initial (30-day) type II endoleak (P = .0015). AAA tortuosity was predictive of midterm type I endoleak (P = .0251). Female sex was associated with lower rates of initial clinical success (P = .0406). The ERA model fitted RBWH data well for early death (C statistic = .906), 3-year survival (C statistic = .735), 5-year survival (C statistic = .800), and initial type I endoleak (C statistic = .850). CONCLUSIONS: The outcomes of elective EVAR at the RBWH are broadly consistent with those of a nationwide Australian audit and recent randomized trials. Age and ASA score are independent predictors of midterm survival after elective EVAR. The ERA model predicts mortality-related outcomes and initial type I endoleak well for RBWH elective EVAR patients.

Important observations made managing carotid body tumors during a 25-year experience.

OBJECTIVES: Our objective was to assess the short- and long-term outcome for patients after carotid body tumor (CBT) resection and discuss the potential pitfalls of the treatment. METHODS: An analysis was undertaken of all patients who underwent CBT resection at Royal Brisbane and Women's Hospital and Greenslopes Private Hospital between 1982 and 2007. Primary tumor characteristics, surgical technique, and outcomes were recorded and analyzed. RESULTS: A total of 49 consecutive CBT resections (2 recurrent tumors) were carried out in 39 patients (26 women [56%]) who were a mean age of 49 years (range, 17-75 years). A nontender neck mass was the presenting complaint in 85%, followed by screening in familial or contralateral tumors in 26%. Familial cases occurred in 11 patients (28%). There were no operative deaths. Complications occurred in 13 of the 49 operations (27%), predominantly temporary nerve palsies and were more likely to occur in tumors of large volume or in cases of removal of coexisting vagal tumors. Malignant disease was present in seven cases (15%). All patients have been followed-up postoperatively for a mean of 11 years (range, 2-26 years). Metachronous paragangliomas have been discovered in six patients, all with familial disease. CONCLUSIONS: Early resection of carotid body tumors should be undertaken while still small to minimize the risk of neural injury, which increases with tumor size. In cases of bilateral CBT, we recommend that the smaller tumor be resected first, before the staged resection of the larger contralateral tumor. In familial or bilateral tumor cases, other synchronous and metachronous paragangliomas should be excluded. Mandatory lifelong follow-up is essential.

Open surgery for atherosclerotic chronic mesenteric ischemia.

BACKGROUND: This study was undertaken to document the results of our current practice of open mesenteric revascularization to enable comparison with the recent trend of percutaneous endovascular therapy for the treatment of chronic mesenteric ischemia. METHODS: Patients were identified via operation code data as well ongoing audit data from 1992 until 2006. Only patients with a history of chronic mesenteric ischemia secondary to atherosclerosis for 3 months or longer were included in the study. Follow-up data have been collected prospectively and include clinical examination and history, as well as graft surveillance consisting of mesenteric duplex ultrasonography, computed tomography, and/or angiography every 6 months for 3 years and then yearly thereafter. RESULTS: Thirty-nine consecutive patients underwent 41 open revascularization procedures for chronic mesenteric ischemia, comprising 67 bypass grafts. The mean patient age was 65 years (range, 45-85 years), and 44% (n = 17) were male. Symptoms were present on average for 11 months (range, 4-48 months) before treatment. The average weight loss was 11.4 kg, and three patients (7.6%) also had evidence of ischemic enteritis. There was one perioperative death, thus giving a perioperative mortality rate of 2.5%. Perioperative morbidity occurred in five patients (12.2%). Primary graft patency was 92% at 5 years. Seven patients died during follow-up, which ranged from 4 to 161 months (mean, 39 months)-one (2.5%) from mesenteric ischemia. Two (5%) other patients have had recurrent mesenteric ischemic symptoms. CONCLUSIONS: Open surgical mesenteric revascularization by bypass grafting for atherosclerotic-induced chronic mesenteric ischemia can be performed with low mortality and morbidity and provides excellent long-term primary patency rates and symptom-free outcomes. Pending more data on the acute and long-term results of endovascular techniques, open mesenteric revascularization remains the gold standard for most patients with chronic mesenteric ischemia.