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.

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.

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.

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.

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.

A comparison of remifentanil and alfentanil for use with propofol in patients undergoing minimally invasive coronary artery bypass surgery.

UNLABELLED: Most patients undergoing minimally invasive direct coronary artery bypass surgery can be awakened and tracheally extubated in the operating room. We have compared two techniques of total IV anesthesia in this patient population: 30 patients (aged 44 to 74 yr; 24 male) premedicated with temazepam were randomly assigned to receive either remifentanil-propofol or alfentanil-propofol. Anesthesia was induced with remifentanil 2 microg/kg or with alfentanil 40 microg/kg, with propofol, and maintained with remifentanil at 0.25 or 0.5 microg x kg(-1) x min(-1) or alfentanil at 0.5 or 1 microg x kg(-1) x min(-1). The stable maintenance infusion rate of propofol was adjusted for age. Times to awakening and tracheal extubation were recorded. Postoperatively, IV morphine provided by patient-controlled analgesia was used for 48 h. Times to awakening and tracheal extubation (mean +/- SD) were shorter (P < 0. 01) in patients receiving remifentanil, and interpatient variations in times to awakening and tracheal extubation smaller (awakening 25 +/- 7 vs 74 +/- 32 min, and extubation 27 +/- 7 vs 77 +/- 32 min). Analysis of variance revealed that postoperative consumption of morphine was dependent on both the intraoperative opioid and the time elapsed after surgery (P < 0.05): patient-controlled analgesia morphine use during the first 3 h after awakening was more in patients receiving remifentanil (P < 0.01). IMPLICATIONS: Recovery of patients undergoing Minimally Invasive Direct Coronary Artery Bypass Surgery is significantly shorter and more predictable after total IV anesthesia with remifentanil-propofol than with alfentanil-propofol, which may be important if the goal is that patients will be awakened and tracheally extubated in the operating room.

Validity of self-reports of fractures in perimenopausal women.

The validity of self-report of fractures in postal inquiry among perimenopausal women was evaluated. Self-reports of fractures in the 1989 baseline postal inquiry data of the Kuopio Osteoporosis Risk Factor and Prevention Study (OSTPRE) were compared with information in patient records. The study population consisted of 373 women who reported fractures sustained during the last 10 years and 200 randomly selected women who did not report fractures from a population base of 2,007 women aged 47-56 years. Self-report as a screening test for fracture was evaluated in the total sample of 2,007 women by estimating the number of false negative reports in all the women who did not report a fracture with the information on these 200 women. Of the self-reports of fractures, 84% proved to be true fractures, 12% soft tissue injuries, and the rest either self-diagnoses or misnomers. Self-report of wrist fracture was more accurate (95%). The sensitivity of self-report to detect fracture was 78% for all fractures and 95% for wrist fracture, while the respective specificities were 96 and 99%. Self-report is a relatively accurate way to obtain information about past major fractures in perimenopausal women. However, it is rather insensitive in the detection of minor fractures, if the reporting period is several years.

Infrarenal endoluminal bifurcated stent graft infected with Listeria monocytogenes.

Prosthetic graft infection as a result of Listeria monocytogenes is an extremely rare event that recently occurred in a 77-year-old man who underwent endoluminal stent grafting for infrarenal abdominal aortic aneurysm. The infected aortic endoluminal prosthesis was removed by means of en bloc resection of the aneurysm and contained endograft with in situ aortoiliac reconstruction. At the 10-month follow-up examination, the patient was well and had no signs of infection.

Angiographic 20-year follow-up of 61 consecutive patients with internal thoracic artery grafts.

OBJECTIVE: To assess the behavior of internal thoracic artery (ITA) grafts versus venous grafts in repeated angiograms up to 20 years. SUMMARY BACKGROUND DATA: Use of ITA grafts to bypass left anterior descending artery stenosis has been shown to be associated with improved survival in patients undergoing coronary artery bypass grafting. METHODS: Sixty-one consecutive patients who received one or two ITA grafts and who underwent surgery from Oct. 5, 1971, to Dec. 18, 1973, in Helsinki University Central Hospital, Finland, were included in this prospective follow-up series. Fifty-six of the patients (92%) also received at least one venous graft. The number of distal anastomoses was 157, of which 47.7% (75) were performed with ITA grafts. The median age of the patients was 47.7 years (range 30.0 to 63.1), and 85% (52) were men. RESULTS: After 20 years of follow-up, 18/20 (90%) of the survivors underwent angiography; the patency rate was 88.9% for ITA grafts and 47.8% for venous grafts. Cumulative graft patency at 20 years, using all the information obtained from repeated angiographic examinations and autopsies, was also calculated to eliminate selection bias. The cumulative 20-year patency rate was 81% for ITA-left anterior descending artery anastomoses, 53.8% for venous graft-right coronary artery anastomoses, and 48.5% for venous graft-left circumflex artery anastomoses. In paired comparisons between anastomoses, the patency time of the ITA-left anterior descending artery anastomoses was on average 2.8 years longer than the venous graft-left circumflex artery patency time and 2.6 years longer than the venous graft-right coronary artery. CONCLUSIONS: Internal thoracic artery grafts, especially in left anterior descending artery anastomoses, should be considered as a primary solution in coronary artery bypass grafting surgery in patients with >10 years of life expectancy; if venous grafting is preferred, further evidence is needed.

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.

Heart transplantation in Finland 1985-1995.

BACKGROUND AND AIMS: Since improved immunosuppression in the 1980's, heart transplantation is a well established procedure to treat patients with end-stage heart failure. The first heart transplantation in Finland was performed in 1985. Since then the activity has gradually increased to a level of about 25 annual transplants. The aim of this report is to sum up the clinical experience during the first 11 years. MATERIALS AND METHODS: From February 1985 till the end of 1995, 190 heart transplantations were performed in our institution. There were 176 males and 14 females ranging from 15 to 62 (mean 42.2) years of age. End-stage preoperative cardiac disease was dilating cardiomyopathy in 108 cases, coronary artery disease in 65 cases, valvular disease in 12 cases and congenital heart disease in five cases. RESULTS: The 30-day hospital mortality was 29 out of 190 (15.2%). The actuarial survival was 77% at one year, 75% at two years and 73% at 10 years. The most common causes of death were rejection (11 cases), graft failure (11 cases), abdominal complications (six cases) and cytomegalovirus (CMV) infection (four cases). A total of 87 rejection episodes occurred in 53 patients consisting 28 per cent of patients. 44 rejections occurred within three months post transplantation. Significant infections were noted in 198 instances in 97 patients. These were of bacterial origin in 92, viral in 48, fungal in 12 and protozoal in 10 cases, and 36 such infections which responded to antibiotics favourably but in which the microbe remained unidentified. 138 infections (i.e. 80%) occurred within 6 months post transplantation. In viral infections cytomegalovirus (CMV) predominated (29 out of 48). The CMV infection was significantly milder in patients who were seropositive preoperatively than in preoperatively seronegative patients with seropositive donors. CMV infection was associated with increased risk of post-transplant coronary artery disease. Three years after transplantation some restoration of sympathetic nervous response was observed at orthostatic test in heart rate and blood pressure. CONCLUSIONS: It can be concluded that 1) if a patient survives the three immediate postoperative months, his prognosis is good for the forthcoming years, 2) clinically significant rejections occur in less than one third of the patients, 3) cytomegalovirus is the most harmful agent post transplantation and a risk factor for post-transplant coronary artery disease and that 4) some restoration of sympathetic nervous control of the heart occurs within three years after transplantation.

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.

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.

Dilatation of ascending aorta in patients with repaired coarctation.

The long-term outcome following repair of typical aortic coarctation in adulthood may be complicated by disorders of the ascending aorta. Follow-up averaging 15 years revealed a 3.8% incidence of dilatation of the ascending aorta after such late repair. Hypertension and concomitant aortic valvular disease were common in these patients. Aortic dilatation can appear years after coarctation repair, irrespective of the operative technique and its success, and can lead to death from aortic dissection or rupture of an aortic aneurysm. Careful follow-up after coarctation repair in adulthood is advisable to detect late aortic complications.

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.

Hematuria is an indication of rupture of an abdominal aortic aneurysm into the vena cava.

During a period of 13 years 11 patients were operated on because of a spontaneous aortocaval fistula caused by a ruptured abdominal aortic aneurysm. The classic diagnostic signs of an aortocaval fistula (pulsatile abdominal mass with bruit and high output heart failure) were present in approximately half of the patients, whereas hematuria was a constant finding in all patients. Six patients had macrohematuria, and five had microhematuria. Seven patients (64% survived, and four had postoperative complications: 1 ileus, 2 postoperative pneumonias, 2 deep venous thrombosis, 1 postoperative hemorrhage. The mean operative blood loss was 7 L. After operation the average follow-up time was 4 years. In four patients who died the perioperative (within 30 days) causes of death were renal failure, a bleeding duodenal carcinoma, myocardial infarction, and operative bleeding. It is concluded that hematuria is a more frequent finding than earlier assumed among patients whose abdominal aortic aneurysm has ruptured into the vena cava. The presence of hematuria in a patient suffering from an abdominal aortic aneurysm is an indication for aortography to rule out an aortocaval fistula.

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.

Diagnosis and treatment of subclavian artery aneurysms.

The diagnostic features and operative results in 13 patients with subclavian artery aneurysms were analysed. Symptoms related to subclavian artery aneurysms were present in seven patients, whereas six patients were asymptomatic and the aneurysm was discovered incidentally on chest X-ray. Angiography was the most valuable diagnostic examination and was also necessary in planning the operation. A correct preoperative diagnosis was made in five of six patients with computed tomography. Resection of the aneurysm was performed in nine and aneurysmal exclusion in the latest four patients. Direct reconstruction was used in nine and in four cases an extra-anatomic carotico-subclavian bypass was performed. Postoperative complications arose in two symptomatic and in four asymptomatic patients (46%: two strokes, two wound infections demanding extirpation of the prosthesis in one patient, two pareses of the recurrent nerve and one postoperative haemorrhage). Operative mortality was one patient. Follow-up data was available for all patients for periods of 6 months to 14 years. The vascular graft was patent in all patients. The authors conclude that subclavian artery aneurysm must be included in the differential diagnosis of all obscure upper mediastinal masses as seen on the chest X-ray and examined with CT and angiography. Exclusion of the aneurysm with extra-anatomical reconstruction is technically easier and gives the same postoperative long-term results as resection of the aneurysm and direct reconstruction. A relatively high complication rate after operation on asymptomatic subclavian aneurysms indicates a need for re-evaluation of operative indications in asymptomatic patients.