On the fate of oxygenated organic molecules in atmospheric aerosol particles.

Highly oxygenated organic molecules (HOMs) are formed from the oxidation of biogenic and anthropogenic gases and affect Earth's climate and air quality by their key role in particle formation and growth. While the formation of these molecules in the gas phase has been extensively studied, the complexity of organic aerosol (OA) and lack of suitable measurement techniques have hindered the investigation of their fate post-condensation, although further reactions have been proposed. We report here novel real-time measurements of these species in the particle phase, achieved using our recently developed extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF). Our results reveal that condensed-phase reactions rapidly alter OA composition and the contribution of HOMs to the particle mass. In consequence, the atmospheric fate of HOMs cannot be described solely in terms of volatility, but particle-phase reactions must be considered to describe HOM effects on the overall particle life cycle and global carbon budget.

Size-dependent influence of NOx on the growth rates of organic aerosol particles.

Atmospheric new-particle formation (NPF) affects climate by contributing to a large fraction of the cloud condensation nuclei (CCN). Highly oxygenated organic molecules (HOMs) drive the early particle growth and therefore substantially influence the survival of newly formed particles to CCN. Nitrogen oxide (NOx) is known to suppress the NPF driven by HOMs, but the underlying mechanism remains largely unclear. Here, we examine the response of particle growth to the changes of HOM formation caused by NOx. We show that NOx suppresses particle growth in general, but the suppression is rather nonuniform and size dependent, which can be quantitatively explained by the shifted HOM volatility after adding NOx. By illustrating how NOx affects the early growth of new particles, a critical step of CCN formation, our results help provide a refined assessment of the potential climatic effects caused by the diverse changes of NOx level in forest regions around the globe.

An evaluation of mitral valve procedures using the European system for cardiac operative risk evaluation.

BACKGROUND AND AIMS: This study was undertaken in order to evaluate the usefulness of the Euroscore in the choice and outcome of mitral valve procedures undertaken at the Helsinki University Central Hospital. MATERIAL AND METHODS: Data from 378 patients was collected. predicted mortalities were calculated for all patients using the European System for Cardiac Operative Risk Evaluation and different mitral valve procedures were compared with 30-day mortality, length of hospital care and rate of post-operative complications. RESULTS: The mortality rate in the mitral valve repair (MVP) group decreased gradually from 5.9% (in 1999) to 2.2% (2003). The variation of annual mortality was higher in the mitral valve replacement (MVR) group. The predicted mortality given by Euroscore increased over the years in both groups. The mortality in the MVR group was nearly four times higher than in the MVP group. the length of both intensive and overall hospital stay decreased in patients with MVP procedures. Post-operative survival was 89% in the MVP patients and 74% in mvr patients after three years. DISCUSSION: The results of mitral valve operations have improved. This is observed as decreased mortality rates and lengths of hospital care in the MVP group, although the predicted mortality rate was increased.

Impact on short-lived climate forcers increases projected warming due to deforestation.

The climate impact of deforestation depends on the relative strength of several biogeochemical and biogeophysical effects. In addition to affecting the exchange of carbon dioxide (CO2) and moisture with the atmosphere and surface albedo, vegetation emits biogenic volatile organic compounds (BVOCs) that alter the formation of short-lived climate forcers (SLCFs), which include aerosol, ozone and methane. Here we show that a scenario of complete global deforestation results in a net positive radiative forcing (RF; 0.12 W m-2) from SLCFs, with the negative RF from decreases in ozone and methane concentrations partially offsetting the positive aerosol RF. Combining RFs due to CO2, surface albedo and SLCFs suggests that global deforestation could cause 0.8 K warming after 100 years, with SLCFs contributing 8% of the effect. However, deforestation as projected by the RCP8.5 scenario leads to zero net RF from SLCF, primarily due to nonlinearities in the aerosol indirect effect.

Treatment of severe peptic esophageal stricture with Roux-en-Y partial gastrectomy, vagotomy, and endoscopic dilation. A follow-up study.

Eleven patients with dysphagia caused by severe esophageal stricture (length 2 to 10 cm) resulting from reflux esophagitis were treated with fibroendoscopic dilation (Eder-Puestow) and Roux-en-Y partial gastrectomy with vagotomy during 10 years (1979 to 1988). There was no operative mortality, but complications developed in three patients: One patient had a mediastinal abscess demanding thoracotomy as a result of esophageal perforation after dilatation; one had postoperative pneumonia; and one patient had ileus. After a mean follow-up of 4 years (range 1 to 10 years) esophagitis healed in all cases, as judged by endoscopy. Eight patients were asymptomatic, but three had slight transient dysphagia. Postoperatively one to eight dilations (average three to four) were needed to relieve dysphagia in the first postoperative year, but later the stricture healed in every case. Postoperative pH measurement was performed in six latest patients and showed complete absence of reflux in all cases. It is concluded that Roux-en-Y partial gastrectomy with vagotomy and endoscopic dilation is an effective, simple, and safe procedure in the management of severe peptic esophageal (acid or alkaline esophagitis) stricture. However, occasional postoperative dilations at the outpatient clinic are often needed in severe cases in the first postoperative year.

Management of delayed esophageal perforation with mediastinal sepsis. Esophagectomy or primary repair?

Ninety patients with esophageal perforations were operated on at our institutions between 1970 and 1992. Thirty-four of them were seen after delayed diagnosis (> 24 hours) with mediastinal sepsis caused by perforation of the thoracic esophagus. There were 18 patients with spontaneous ruptures, 11 with instrumental perforations (including one caused during laparotomy), and 3 perforations caused by foreign bodies. One patient had perforation of an esophageal ulcer into the pericardium and another had perforation of an esophageal diverticulum into the mediastinum. Nineteen patients underwent primary repair of the perforation with cleansing and drainage of the mediastinum and the pleural cavity. The remaining 15 had primary extirpation of the thoracic esophagus, irrigation of the mediastinum with antibiotics, cervical esophagostomy, gastrostomy, and drainage of the mediastinum and pleural cavity. Nineteen of the 34 patients survived (hospital mortality 44%). Of patients with primary repair, only six survived (in-hospital mortality 68%), whereas only two patients treated with esophagectomy died (in-hospital mortality 13%). The difference was highly significant (p = 0.001). The most common cause of death was multiorgan failure resulting from sepsis. Postoperative complications developed in four patients treated with primary repair (two sepsis, one empyema, and one anuria) and in seven patients treated with esophagectomy (two empyema, two sepsis, one pneumonia, one mediastinal abscess, and one brain abscess). After healing of the mediastinitis, the esophagogastric continuity was reconstructed with colon in 11 patients and stomach in two patients. In the management of delayed esophageal perforation with mediastinal sepsis, esophagectomy is superior to primary repair alone, which often leads to mediastinal leakage, continued sepsis, and death.

Long-term results of direct aortoplasty for repair of aortic coarctation in adults.

The long-term results of 14 adult patients who underwent a direct aortoplasty for aortic coarctation were reviewed. The mean age of the patients at operation was 31.5 years. Three of the patients died; 1 died perioperatively, and 2 died later of cardiovascular disease. The survivors were followed for 15.8 years. None of the patients had complications at the site of coarctation repair. This contrasts with our earlier findings on patch graft aortoplasties, which showed a high incidence of postoperative aneurysm at the repair site. The etiology of these aneurysms is discussed with reference to the information provided by the present study.

Aneurysms after patch graft aortoplasty for coarctation of the aorta: long-term results of surgical management.

Twenty-two (32.8%) of 67 patients who had patch graft aortoplasty for aortic coarctation underwent reoperation because of aneurysm formation opposite or at the site of the patch. The mean age at primary repair was 25.3 years (standard deviation, 9.5 years). Reoperation took place 12.3 years (standard deviation, 3.7 years) later. In 19 patients, the aneurysm was resected and the aorta reconstructed with a tubular prosthesis. In 3 patients, the aneurysm was given external support. There were no hospital deaths. Recurrent nerve paralysis (36%) and bleeding necessitating repeat thoracotomy (32%) were the most common complications. Mean follow-up was 4.6 years. No aneurysms developed at the site of reoperation. Two patients died of causes not related to reoperation. Reconstruction with a tubular prosthesis gives good long-term results in patients with aneurysm formation after patch grafting for coarctation. External support offers technical advantages in select patients. Close follow-up of patients who have coarctation repair with a patch graft is essential.

Morphological and histopathological aspects of aneurysms after patch aortoplasty for coarctation.

Repair of coarctation of the aorta by synthetic patch grafting has been complicated by late aneurysm formation. These aneurysms differ macroscopically from atherosclerotic thoracic aortic dilatations. Specimens for microscopic examination were taken from 14 of 20 patients undergoing aneurysm resection. Histological analysis of the specimens showed medionecrosis in 13 patients of the specimens showed medionecrosis in 13 patients (93%), foreign body reaction in 11 patients (78%), and intimal thickening in 3 patients (21%). The three layers of the aortic wall could be identified in the aneurysms. On the basis of these results, we discuss the etiologic factors and pathogenetic mechanisms involved in the development of these aneurysms.

A MATLAB package for the EIDORS project to reconstruct two-dimensional EIT images.

The EIDORS (electrical impedance and diffuse optical reconstruction software) project aims to produce a software system for reconstructing images from electrical or diffuse optical data. MATLAB is a software that is used in the EIDORS project for rapid prototyping, graphical user interface construction and image display. We have written a MATLAB package (http://venda.uku.fi/ vauhkon/) which can be used for two-dimensional mesh generation, solving the forward problem and reconstructing and displaying the reconstructed images (resistivity or admittivity). In this paper we briefly describe the mathematical theory on which the codes are based on and also give some examples of the capabilities of the package.

Surgical treatment of acute myocardial ischaemia related to coronary angioplasty with special reference to use of perfusion balloon catheter and long-term outcome.

Twenty of 569 consecutive patients (3.5%) undergoing percutaneous transluminal coronary angioplasty required emergency coronary artery bypass grafting for acute closure of the dilated vessel. In seven patients an intracoronary autoperfusion balloon catheter was inserted to ensure antegrade blood flow across the injured zone of the coronary artery. The time needed for completion of the bypass grafts ranged from 100 to 399 minutes (mean 180 minutes). An average of 1.9 coronary artery bypasses was inserted. In total, 11 of the 20 patients (55%) developed new Q waves and had elevated CK-MB levels. However, the myocardial infarction rate was only 14% in those with a perfusion balloon catheter as against 77% in those without one. The insertion of a ball-out catheter permitted greater utilization of the internal mammary artery as a bypass graft. Angiographic follow-up was conducted after a mean of 28 months (19 patients). The patency rate of the bypass grafts placed in the emergency setting was relatively good (91%). Thallium tomography revealed a scar of variable size in all 17 patients studied and a reversible exercise perfusion defect requiring coronary reangioplasty in three patients. In conclusion, the insertion of a perfusion balloon catheter after abrupt coronary occlusion during coronary angioplasty solved the problems of acute myocardial ischemia and markedly lowered the definite myocardial infarction rate. This technique ensures favourable haemodynamic conditions for emergency myocardial revascularization.

Polydioxanone in coronary vascular surgery.

We have used polydioxanone (PDS) in 50 patients who underwent coronary artery bypass grafting. The anastomoses consisted of suturing an autologous vein graft to the coronary artery (122 operations), a vein graft to the aorta (63 operations) and the internal mammary artery to the coronary artery (33 operations). The recipient coronary artery was subjected to endarterectomy in 28 instances. The anastomoses proved to be reliable in the early postsurgical period; no bleeding was attributed to the PDS suture. Clinical follow-up for a maximum of two-and-half years, completed using control coronary angiograms in selected cases, demonstrated good results. The practical properties of PDS were evaluated to be at least as good as those of polypropylene. Experiments have clearly shown that small artery anastomoses heal more favourably after the use of absorbable sutures than after the use of nonabsorbable sutures. Because of this finding and on the basis of our clinical experience, we believe the application of PDS in coronary surgery should be recommended as an alternative treatment.

Clinically significant neurological disorders following open heart surgery.

In 1982, 364 consecutive adult patients with congenital and acquired heart disease were operated on using cardiopulmonary bypass (CPB). This population was analysed to determine the frequency of neurological complications and possible risk factors. One hundred fifty-four patients were studied prospectively (group I) and the results of 151 patients were reviewed retrospectively (group II). The overall surgical mortality was 4.5%. A neurological event was not the primary cause of death in any patients. Twenty-one patients (5.8%) had clinically significant neurological disturbances postoperatively, of these 85.7% were central and 14.3% peripheral nerve pareses. Patients with neurological complications (21) and the patients who did not survive the operation (16) were compared with a control group (59 cases) with no neurological defects operated on during the same year. Age of the patient, duration of CPB and low CPB pressure were not associated with neurological complications. Previous neurological events seem to have an influence on the postoperative neurological status although this could not be proved statistically. Except for 2 cases the neurological disturbances were transient with complete recovery or improved symptoms at the time of discharge.

Neurological events in cardiac surgery.

Fifty consecutive coronary artery bypass grafting (Group I) and 50 single valve replacement (Group II) procedures were compared with 50 coronary artery bypass grafting with valve replacement (Group III) procedures and 50 multi-valve procedures (Group IV) to determine the frequency of neurological complications after cardiopulmonary bypass (CPB). The possible risks and aetiological implications were studied. The overall surgical mortality rate was 7.5%, being 0%, 4%, 6% and 20%, respectively for the different groups. The neurological event was not the primary cause of death in any of the patients. After CPB, neurological manifestations occurred in 4% of the patients in Gr. I, in 6% in Gr. II, in 4% in Gr. III, and in 8% in Gr. IV. Three patients had peripheral nerve paresis. The age of the patients and the duration of the CPB operation were not factors in the risk of neurological complications. Previous neurological events seemed to increase the frequency of postoperative neurological disorders, whereas combined procedures were no more dangerous in this respect.

Acute renal failure related to open-heart surgery.

Open-heart surgery was performed on 1686 adult patients between 1980 and 1984. The patients were operated on using cardiopulmonary bypass procedures (CPB). Fifteen patients developed acute renal failure (ARF) after CPB, i.e. the incidence of ARF was 0.9%. All these patients were treated by peritoneal dialysis or haemodialysis. Pre-operative possible risk factors in the ARF group were compared to those in a control group of 30 patients (15 consecutive coronary artery bypass grafting and 15 consecutive valve repair procedures) experiencing no complications. Age, New York Heart Association (NYHA) classification, ejection fraction, cardiac volume and left ventricular end-diastolic pressure were not risk factors for the development of renal failure. The incidence of thrombocytopenia after CPB was statistically significantly different between the control and ARF groups. The mortality from ARF was 66.6%. The causes of death were peri-operative myocardial infarction, infection and gastrointestinal bleeding. CPB time, perioperative events and postoperative infection were the main factors contributing to ARF. Renal failure was twice as common in valve procedures as in coronary artery revascularization procedures. Impairment of renal function proved reversible only in those patients who survived. After restoration of renal function the prognosis was good.

One-stage vascular surgery for abdominal aortic aneurysm infected by salmonella.

A case is presented of abdominal aortic aneurysm infected with salmonella enteritidis, maintaining septicaemia. Immediate surgery became necessary because of imminent rupture of the aneurysm. The infected thrombus within the aneurysmal sac was debrided, with irrigation of antibiotic solution, and in situ aorto-iliac reconstruction was carried out. A prolonged course of ciprofloxacine and a short course of vancomycin were administered. Recovery was uneventful. The infection parameters are normal 6 months postoperatively and CT-scan shows no signs of periprosthetic infection. The relevant literature concerning the surgical procedures for mycotic aneurysms is reviewed.

Abdominal complications following cardiopulmonary bypass in open-heart surgery.

Open-heart surgery was performed on 1686 adult patients between 1980 and 1984, with a mortality rate due to abdominal complications of 0.6%. Every operation involved the use of cardiopulmonary bypass (CPB). Abdominal complications occurred in 1.6%, with an overall mortality rate of 36%. The most frequent complication was gastrointestinal (Gl) bleeding (61%). The mortality of the patients who bled from the Gl tract was 53%. Other complications encountered were gastroduodenal ulcer, colitis, ileus, subphrenic abscess and intraperitoneal bleeding. Prolonged CPB and low output syndrome preceded multiple organ failure, which occurred in 39% of those who had abdominal complications and in 59% of those who bled. Gl bleeding after CPB did not correlate with a previous history of gastric ulcer. Reoperation because of cardiac tamponade or excessive chest tube drainage was a factor predisposing to Gl bleeding. The mortality and abdominal complication rates were significantly higher in valve surgery than in coronary revascularization.

Polydioxanone in cardiovascular surgery.

Polydioxanone (PDS) suture material was used in vascular anastomoses in patients submitted to femoropopliteal bypass (10 patients), aortoiliac endarterectomy (5 patients), and aortocoronary bypass (5 patients). Clips of this material and conventional metallic clips were compared in vitro for holding-in-place properties, and PDS clips were used in ligation of branches of the autologous vein grafts in femoropopliteal bypass (10 patients) and aortocoronary bypass (10 patients). There were no complications related to the PDS material either intraoperatively or during the follow-up from 3 to 6 months. The PDS clips did not slip when burst-tested in vitro. The material is suitable and advantageous in cardiovascular operations where autologous tissue is handled.