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.

Interprofessional education of medical students and paramedics in emergency medicine

BACKGROUND

Emergency medicine is team work from the field to the hospital and therefore it is also important for physicians to understand the work of paramedics, and vice versa. Interprofessional emergency medicine education for medical and paramedic students in Helsinki was started in 2001. It consisted of a 15 European credit transfer system (ECTS) credits programme combining 22 students in 2001. In 2005, the number of students had increased to 25. The programme consisted of three parts: acute illness in childhood and adults (AI), advanced life support (ALS) and trauma life support (TLS). In this paper, we describe the concept of interprofessional education of medical students and paramedics in emergency medicine.

METHODS

After finishing the programmes in 2001 and in 2005, the students' opinions regarding the education were collected using a standardized questionnaire.

RESULTS

There were good ratings for the courses in AI (2001 vs. 2005, whole group; 4.3 +/- 0.7 vs. 4.2 +/- 0.4, P = 0.44) ALS (4.7 +/- 0.5 vs. 4.4 +/- 0.5, P = 0.06) and TLS (3.9 +/- 0.7 vs. 4.4 +/- 0.5, P = 0.01) in both years. Most of the medical students considered that this kind of co-education should be arranged for all medical students (2001 vs. 2005; 4.8 +/- 0.6 vs. 4.4 +/- 0.5, P = 0.02) and should be obligatory (3.5 +/- 1.5 vs. 3.1 +/- 1.3, P = 0.35).

CONCLUSIONS

Co-education was well received and determined by the students as an effective way of improving their knowledge of emergency medicine and medical skills. The programme was rated as very useful and it should be included in the educational curriculum of both student groups.

Ranitidine or dobutamine alone or combined has no effect on gastric intramucosal-arterial PCO(2) difference after cardiac surgery

OBJECTIVE

To test the hypothesis that ranitidine, either alone or in combination with dobutamine, modifies the gastric intramucosal-arterial PCO(2) difference.

DESIGN

Full factorial design (double-blinded for ranitidine).

SETTING

Intensive Care Unit of a university hospital.

PATIENTS

Sixty-four haemodynamically stable coronary artery bypass surgery patients.

INTERVENTIONS

Ranitidine (150 mg preoperatively per os and 50 mg intravenously postoperatively) and dobutamine (4 micro g. kg(-1). min(-1) for 3 h postoperatively) were administered in four randomised groups of patients: preoperative and postoperative ranitidine, either alone (n = 15) or in combination with dobutamine (n = 17), dobutamine alone (n = 15) or neither ranitidine nor dobutamine (n = 17).

MEASUREMENTS AND RESULTS

Gastric intramucosal-arterial PCO(2) difference was measured during the first 5 postoperative hours. No differences in the postoperative pattern of gastric intramucosal-arterial PCO(2) difference were found among the groups.

CONCLUSIONS

Ranitidine and dobutamine have no effect on the gastric tonometry results on intramucosal-arterial PCO(2) difference after uncomplicated cardiac surgery. Hence, the routine use of H(2)-antagonists for gastrointestinal tonometry is not warranted. Our results must be limited to results obtained by tonometry; they do not allow any conclusions on the effects of these drugs on splanchnic blood flow or its distribution.

Epidural analgesia with bupivacaine does not improve splanchnic tissue perfusion after aortic reconstruction surgery

Inadequate splanchnic tissue perfusion is relatively common during and after aortic surgery. We hypothesized that vasodilation caused by thoracic epidural analgesia improves splanchnic blood flow and tissue perfusion after aortic surgery. In this prospective, randomized, controlled study, we studied 20 patients undergoing elective aortic-femoral or aortic-iliac reconstruction surgery. Gastric and sigmoid colon mucosal PCO2 and pH were measured during surgery. An epidural bolus of bupivacaine 40 mg followed by infusion of 15 mg h-1 was started after operation in 10 patients. After operation, splanchnic blood flow and gastric and sigmoid colon mucosal PCO2 and pH were measured before and 2 h after the start of epidural analgesia. During surgery, the gastric mucosal-arterial PCO2 difference remained stable, whereas the sigmoid mucosal-arterial PCO2 difference increased during aortic clamping but returned to pre-clamping values after declamping. After operation, epidural analgesia had no effect on gastric or sigmoid mucosal-arterial PCO2 differences or on splanchnic blood flow.

Enzyme-linked immunosorbent assay for mumps and parainfluenza type 1 immunoglobulin G and immunoglobulin M antibodies

A solid-phase enzyme-linked immunosorbent assay (ELISA) for detection of mumps and parainfluenza type 1 antibodies (immunoglobulin G [IgG] and IgM classes) is described and compared with the conventional complement fixation (CF) test. A highly positive correlation was found between mumps IgG ELISA and the mumps CF test, whereas parainfluenza type 1 IgG ELISA had only a moderate positive correlation with the respective CF test. Mumps IgM antibodies could be demonstrated in all patients with serologically verified and clinically typical (parotitis, meningitis, or orchitis) mumps virus infection, but not in patients with rises in parainfluenza CF titers. Mumps IgM was already present in the acute-phase sera if they were not taken during the first 2 days after onset of disease. Mumps IgM was also found in some paired sera that were taken too late to demonstrate any significant increase in the antibody titers by CF. Therefore, mumps IgM ELISA provides an improvement over the conventional laboratory diagnosis of mumps infection, since the measurement of specific IgM antibodies in a single serum by ELISA is diagnostic, rather than the identification of a fourfold or greater rise in CF antibody titer. An unexpected finding was that parainfluenza type 1 IgM antibodies could not be demonstrated by ELISA in paired sera with rises in parainfluenza CF titers, suggesting a different antibody response from that occurring in mumps infection.