Understanding STAT3 signaling in cardiac ischemia.

Cardiovascular disease is the leading cause of death worldwide. It remains one of the greatest challenges to global health and will continue to dominate mortality trends in the future. Acute myocardial infarction results in 7.4 million deaths globally per annum. Current management strategies are centered on restoration of coronary blood flow via percutaneous coronary intervention, coronary artery bypass grafting and administration of anti-platelet agents. Such myocardial reperfusion accounts for 40-50 % of the final infarct size in most cases. Signaling transducer and activator of transcription 3 (STAT3) has been shown to have cardioprotective effects via canonical and non-canonical activation and modulation of mitochondrial and transcriptional responses. A significant body of in vitro and in vivo evidence suggests that activation of the STAT3 signal transduction pathway results in a cardio protective response to ischemia and attempts have been made to modulate this with therapeutic effect. Not only is STAT3 important for cardiomyocyte function, but it also modulates the cardiac microenvironment and communicates with cardiac fibroblasts. To this end, we here review the current evidence supporting the manipulation of STAT3 for therapeutic benefit in cardiac ischemia and identify areas for future research.

Ground water as a silica source for diatom production in a precipitation-dominated lake.

The short-term, seasonal input of ground water to a small, precipitation-dominated oligotrophic lake in northern Wisconsin amounts to less than 10 percent of the annual water budget of the lake but accounts for nearly all the external silica loading. Silica is a necessary nutrient for diatoms. A large spring diatom bloom occurs coincident with high silica inputs from ground water when other possible silica sources are low. The mass budgets of ground water and silica in the lake system demonstrate the importance of ground-water solute inputs to the lake.

Rapid pre-concentration of mercury in solids and water for isotopic analysis.

The precise quantification of mercury (Hg) stable isotope compositions in low concentration or dilute samples poses analytical challenges due to Hg mass limitations. Common Hg pre-concentration procedures require extended processing times, making rapid Hg stable isotope measurements challenging. Here we present a modified pre-concentration method that combines commonly used Hg reduction and gold trap amalgamation followed by semi-rapid thermal desorption (less than 1 h) and chemical trapping. This custom designed system was demonstrated to perform adequately on multiple trapping matrices including a new bromine monochloride (BrCl) wet oxidant trap (40% 3HNO3:BrCl), capable of trapping consistently in 2 mL volume over a wide range of Hg masses (5-200 ng). The procedure was also shown to work effectively on natural matrices, waters and sediments, producing comparable isotope results to the direct digestion analyses. Here, we present a method that can effectively triple sample throughput in comparison to traditional procedures, and also access lower concentration matrices without compromising the accuracy or precision of Hg isotope measurements.

Influence of natural dissolved organic carbon on the bioavailability of mercury to a freshwater alga.

Bioavailability of mercury (Hg) to Selenastrum capricornutum was assessed in bioassays containing field-collected freshwater of varying dissolved organic carbon (DOC) concentrations. Bioconcentration factor (BCF) was measured using stable isotopes of methylmercury (MeHg) and inorganic Hg(II). BCFs for MeHg in low-DOC lake water were significantly larger than those in mixtures of lake water and high-DOC river water. The BCF for MeHg in rainwater (lowest DOC) was the largest of any treatment. Rainwater and lake water also had larger BCFs for Hg(II) than river water. Moreover, in freshwater collected from several US and Canadian field sites, BCFs for Hg(II) and MeHg were low when DOC concentrations were >5mg L(-1). These results suggest high concentrations of DOC inhibit bioavailability, while low concentrations may provide optimal conditions for algal uptake of Hg. However, variability of BCFs at low DOC indicates that DOC composition or other ligands may determine site-specific bioavailability of Hg.

Understanding Complete Pathologic Response in Oesophageal Cancer: Implications for Management and Survival.

Despite significant improvement over recent decades, oesophageal cancer survival rates remain poor. Neoadjuvant chemoradiotherapy followed by oesophageal resection is mainstay of therapy for resectable oesophageal tumours. Operative morbidity and mortality associated with oesophagectomy remain high and complications arise in up to 60% of patients. Management strategies have moved towards definitive chemoradiotherapy for a number of tumour sites (head and neck, cervical, and rectal) particularly for squamous pathology. We undertook to perform a review of the current status of morbidity and mortality associated with oesophagectomy, grading systems determining pathologic response, and data from clinical trials managing patients with definitive chemoradiotherapy to inform a discussion on the topic.

The 100 most cited publications in cardiac surgery: a bibliometric analysis.

INTRODUCTION: This study is a citation analysis of the top 100 most cited papers in adult cardiac surgery. Bibliometric analyses are viewed as a proxy marker of a paper's influence and, therefore, an analysis of the most influential papers published in recent decades. METHODS: Impact factor ranking as of 2012 was used to decide which journals to include in our searches. The Thompson Reuters Web of Knowledge was used to search for citations of all papers relevant to cardiac surgery within selected journals. Journals in the areas of surgery, cardiothoracic surgery, general medicine, anaesthesia, perfusion and pathology were included. RESULTS: The most frequently cited paper was found to be that of Nashef et al. (Eur J Cardiothorac Surg 16(1):9-13, 1999) introducing the EuroSCORE operative risk evaluation system. A number of authors including Alderman, Carpentier and Cox had more than one paper in the top 100. CONCLUSION: Despite the potential flaws with bibliometric analysis, and its application to cardiac surgery, there is inherent merit in an analysis of this type.

Video-assisted thoracic surgery for delayed pericardial effusion post-CABG.

Delayed-onset pericardial effusion following coronary artery bypass grafts can give rise to significant morbidity in its presentation and in its management by traditional surgical techniques. A video-assisted thoracoscopic technique to create a pericardial window, with the advantage of a minimally invasive approach combined with excellent visualization in such a patient is described.

Effects of gilvin on the composition and dynamics of metalimnetic communities of phototrophic bacteria in freshwater North-American lakes.

The spectral distribution of light reaching the populations of phototrophic bacteria in the metalimnion of stratified lakes is a selective factor determining the community composition. At deep metalimnia, light spectra are enriched in photons of the central part of the spectrum (500-600 nm) and benefit Chromatiaceae, brown-coloured Chlorobiaceae and phyco-erythrine-containing cyanobacteria. Their carotenoids (okenone, spiriloxanthine, isorenieratene) and phycoerythrines allow these phototrophic bacteria to use light from the narrow central spectral wavebands. Otherwise, shallow metalimnetic communities receive light from a wide range (400-800 nm) and their composition is more diverse and usually enriched in green-coloured Chlorobiaceae, which are unable to take advantage of the central part of the spectrum. Gilvin compounds (humic substances dissolved in water), have strong effects on light absorption, especially at shorter wavelengths. Therefore, light spectra in lakes with high gilvin contents are enriched in photons of long wavelengths (> 600 nm). Several Wisconsin lakes with different gilvin contents were studied during the period of summer stratification in 1994. Spectral distribution of light reaching their metalimnia changed with increasing gilvin contents (measured as g(440) ). In the latter, phototrophic metalimnetic bacterial communities were absolutely dominated by green-coloured Chlorobiaceae. Intermediate lakes could experiment changes on their community composition depending on variations in gilvin content, as happened in Little Long lake. The dynamics of this lake was studied during summer 1995. The ratio of green-coloured species in respect to brown-coloured species increased after a sudden increase of gilvin due to strong rainfall. These results agree with the photosynthetic advantage of green-coloured Chlorobiaceae under red-light illumination, inferred from laboratory experiments, and suggest a bacteriochlorophyll-dependent, light-harvesting strategy of these phototrophic sulphur bacteria.

Energy of the oscillating legs of a fast-moving cheetah, pronghorn, jackrabbit, and elephant.

Lifelike models of the oscillating legs treated as three-segment systems show the course of kinetic and potential energy over the locomotor cycle for a cheetah, pronghorn, jackrabbit, and elephant running at speeds approaching their maxima. The models can be adjusted to eliminate differences among the animals in time intervals, mass or length of limb, and joint angles. This facilitates analysis of the influence on total energy of each of these variables and of the distribution of mass among leg segments. Fast-cycling legs of the carnivore type have significantly more energy than those of the hoofed type. This may contribute to the lesser endurance that is usual for carnivores that hunt using a high-speed dash.

Retrospective analysis of the utility of video-assisted thoracic surgery in 100 consecutive procedures.

One hundred consecutive video-assisted thoracic surgery (VATS) procedures, diagnostic (n = 54) and therapeutic (n = 46), in 90 patients over a 2-year period are reviewed. Hospital mortality was 2%. Conversion to formal thoracotomy was required in 3%, and re-exploration for bleeding in 1%. Seven patients required intensive care unit facilities postoperatively. The technique described was safe and there was minimal postoperative morbidity. Diagnostic VATS was of particular use in cases of indeterminate pulmonary masses (Sensitivity of 96%), anterior mediastinal masses and in immunocompromised patients. Video-assisted thoracic surgery may now be the treatment of choice for recurrent pneumothoraces and it demonstrated potential for development in a variety of other benign thoracic disorders. This method had a limited role in the management of empyaema with a 60% conversion rate to formal thoracotomy. Pulmonary resections were feasible but its role in the treatment of malignancy is questioned.

Imaged thoracoscopic surgery--patent ductus arteriosus ligation.

Video-assisted thoracic surgery (VATS) combines excellent visualization of the intrathoracic structures with a minimally invasive technique. A patient is presented who underwent successful ligation of a patent ductus arteriosus with a video-assisted thoracoscopic technique.

Surgical relief of tracheobronchial obstruction in infants and children.

OBJECTIVE: Congenital tracheobronchial obstruction (TBO) presents a complex problem both in terms of diverse aetiology, presence of associated anomalies and the operative strategy to be adopted. We report a single centre experience in managing this difficult problem. METHODS: Twenty-four infants and children with TBO referred to our unit over a 12-year period are reviewed. Aetiology of TBO included vascular rings (n = 9), anomalous innominate artery (n = 6), congenital tracheal stenosis (n = 5), segmental bronchial stenosis (n = 2) and pulmonary artery compression of the main bronchi (n = 2). Seven patients had concurrent cardiac anomalies. Stridor was the commonest presenting symptom (67%). Mean delay from onset of symptoms to referral was 19 months. One patient died preoperatively due to acute airway obstruction. Mean age at operation was 33.1 +/- 42 months (range 4 days-156 months) and 11 children were under 1 year at the time of surgery. In cases of TBO secondary to vascular rings, division of the ring resulted in relief of symptoms in seven cases, with two requiring further surgery for resultant tracheomalacia. Four of the five patients having tracheal resection were operated on with the use of cardiopulmonary bypass; three of these patients had concurrent correction of cardiac lesions, with two survivors. Tracheobronchial anastomoses were carried out using continuous polydioxanone (PDS). Patients with anomalous innominate arteries required aortopexy in five and innominate artery suspension in one, while those with pulmonary artery compression of the main bronchi had correction of their intracardiac defects (n = 2). RESULTS: Hospital mortality was 8.7% and there has been one late death due to Eisenmenger syndrome secondary to pulmonary regurgitation, atrial septal defect (ASD) and patent ductus arteriosus (PDA). On follow-up (mean 40 +/- 31 months), 19 patients are alive and symptom free. There have been no anastomotic strictures following tracheobronchial resection. The single most important predictor of mortality was the presence of associated cardiac anomalies. CONCLUSIONS: TBO can be managed effectively by a single operation in both infants and children without a detrimental effect on tracheal growth. We advocate consideration of concurrent repair of the tracheal and cardiac lesions. Cardiopulmonary bypass (CPB) allows this concurrent correction of cardiac lesions and also facilitates tracheal resection.

Hemolymphangioma in a neonate--a therapeutic problem--case history.

The authors present the case of a one and one-half-day-old child with a 4 X 5 cm hemolymphangioma of the left lower extremity. The mass was a violaceous, protuberant, compressible tumor covered with distended peau d'orange skin. A pressure dressing was applied to the lesion, and it was made certain that the blood supply to the foot was not cut off. The lesion began to resolve within a week and over the next few months; however, pressure may need to be continued for her lifetime. The patient had been wearing a pressure-gradient leotard as of six months of age, but this was discontinued after two weeks because of the authors' inability to converse with the child to determine how much pressure could be safely employed. This is one example of a to date successfully treated hemolymphangioma in a neonate using a pressure dressing initially followed by combined compression therapy. The proposed mechanism of this therapy, as well as comparison with other types of therapy, is discussed.

The diverse potential of thoracoscopic assisted surgery.

Thoracoscopy has been a part of thoracic surgical practice for many years. The introduction of the camera chip and newer instrumentation has awakened a new interest in this technique and led to the development of video-assisted thoracic surgery (VATS). One hundred and seventy consecutive procedures performed on 158 patients are reviewed. Video-assisted techniques have proven useful in a broad spectrum of thoracic surgical procedures both diagnostic (n = 90) and therapeutic (n = 80). Hospital mortality was 1.3%. Conversion to formal thoracotomy was required in 2.5%, and re-exploration for bleeding in 0.6%. The technique was safe and the incidence of complications acceptable. VATS was particularly helpful in diagnosing "indeterminate" pulmonary nodules (sensitivity of 95%), interstitial lung disease (histological diagnosis in all), anterior mediastinal masses and post transplant pneumonitis. VATS may now be the surgical treatment of choice in those with spontaneous pneumothorax, and it also proved useful in a variety of benign disorders. Its role in the management of empyaema is limited with a 57% conversion rate. While pulmonary resections are feasible, its role in the therapeutic management of malignancy is questioned. Further studies are required to define the precise role of VATS in thoracic surgery.

A preventable cause of tracheal injury at oesophagectomy.

Advocates of transhiatal oesophagectomy warn of the danger of tracheal injury resulting from the blind dissection of tumours of the upper and middle thirds of the oesophagus when the tumour has invaded the membranous part of the trachea. We report an unusual cause of tracheal injury at transhiatal oesophagectomy due to dissection at the level of the inflated endotracheal cuff in a patient with a tumour at the gastro-oesophageal junction.

Video assisted thoracic surgery.

Using video thoracoscopic techniques in 30 patients over a twelve month period we have been able to perform 33 procedures that would have been previously performed by thoracotomy, with its associated morbidity. We have found the applications of this procedure to be diverse, being both diagnostic (n = 16) and therapeutic (n = 17). The diagnostic procedures were associated with a high diagnostic yield and allowed accurate staging. The therapeutic procedures were associated with minimal morbidity and short hospital stay. Our experience indicates an established and expanding role for Video Assisted Thoracic Surgery.

Emergency pulmonary embolectomy.

Pulmonary embolectomy maybe a life saving procedure in the unresponsive hypotensive patient following a massive pulmonary embolectomy despite optimal medical therapy. We report a successful pulmonary embolectomy in a 47 year old patient, three days post post coronary artery bypass grafting (CABG) and a new approach to the problem of caval filters in such patients. This case demonstrates the benefit of early surgery in this life threatening situation.

Transhiatal oesophagectomy--its role for tumours of the middle third of the intrathoracic oesophagus.

All patients presenting to a regional unit with oesophageal carcinoma over a twelve month period are reviewed and the role of transhiatal oesophagectomy for tumours of the middle third of the intrathoracic oesophagus is evaluated. Of the 28 cases of oesophageal carcinoma, 22 (78%) were resected by blunt transhiatal oesophagectomy, the remaining six (22%) has various forms of palliative treatment. In the resected group post-operative morbidity was compared in patients with tumours of the middle third to those with lower and upper third tumours combined. There was one post-operative death in each group giving an overall operative mortality of 9%. Resection for carcinoma of the middle third (N = 7) resulted in a complication rate of 50% and a mean ICU stay of 19.5 days as opposed to a complication rate of 35% and a mean ICU stay of ten days (P = 0.050) for tumours of upper and lower third combined (N = 15). On the basis of these figures we question whether transhiatal oesophagectomy, despite its many advantages, can be applied safely to tumours of the middle third of the intrathoracic oesophagus.

Sealed operation of a rf driven ion source for a compact neutron generator to be used for associated particle imaging.

We present the recent development of a prototype compact neutron generator to be used in conjunction with the method of associated particle imaging for the purpose of active neutron interrogation. In this paper, the performance and device specifications of these compact generators that employ rf driven ion sources will be discussed. Initial measurements of the generator performance include a beam spot size of 1 mm in diameter and a neutron yield of 2x10(5) n/s with air cooling.