New particle formation in the free troposphere: A question of chemistry and timing.

New particle formation (NPF) is the source of over half of the atmosphere's cloud condensation nuclei, thus influencing cloud properties and Earth's energy balance. Unlike in the planetary boundary layer, few observations of NPF in the free troposphere exist. We provide observational evidence that at high altitudes, NPF occurs mainly through condensation of highly oxygenated molecules (HOMs), in addition to taking place through sulfuric acid-ammonia nucleation. Neutral nucleation is more than 10 times faster than ion-induced nucleation, and growth rates are size-dependent. NPF is restricted to a time window of 1 to 2 days after contact of the air masses with the planetary boundary layer; this is related to the time needed for oxidation of organic compounds to form HOMs. These findings require improved NPF parameterization in atmospheric models.

Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry.

Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H2SO4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H2SO4 in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI-APi-TOF (Chemical Ionization-Atmospheric Pressure interface-Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI-APi-TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (<5 to 70 pptv) the sulfuric acid monomer measured by the CIMS represents only a fraction of the total H2SO4, contained in the monomer and the clusters that is available for particle growth. Although it was found that the addition of dimethylamine dramatically changes the H2SO4 cluster distribution compared to binary (H2SO4-H2O) conditions, the CIMS detection efficiency does not seem to depend substantially on whether an individual H2SO4 monomer is clustered with a DMA molecule. The experimental observations are supported by numerical simulations based on A Self-contained Atmospheric chemistry coDe coupled with a molecular process model (Sulfuric Acid Water NUCleation) operated in the kinetic limit.

Regurgitant flow in cardiac valve prostheses: diagnostic value of gradient echo nuclear magnetic resonance imaging in reference to transesophageal two-dimensional color Doppler echocardiography.

Gradient echo nuclear magnetic resonance (NMR) imaging and transesophageal two-dimensional color Doppler echocardiography are flow-sensitive techniques that have been used in the diagnosis and grading of valvular regurgitation. To define the diagnostic value of gradient echo NMR imaging in the detection of regurgitant flow in cardiac valve prostheses and the differentiation of physiologic leakage flow from pathologic transvalvular or paravalvular leakage flow, 47 patients with 55 valve prostheses were examined. Color Doppler transesophageal echocardiography was used for comparison. Surgical confirmation of findings was obtained in 11 patients with 13 valve prostheses. Gradient echo NMR imaging showed regurgitant flow in 37 of 43 valves with a jet seen on transesophageal echocardiography and it detected physiologic leakage flow in 4 additional valves. There was 96% agreement between the two methods in distinguishing between physiologic and pathologic leakage flow. The methods differed on jet origin of pathologic leakage flow in six prostheses. The degree of regurgitation was graded by both NMR imaging and transesophageal echocardiography, according to the area of the regurgitant jet visualized; gradings were identical for 75% of valve prostheses. Quantification of jet length and area showed a good correlation between the two methods (r = 0.85 and r = 0.91, respectively). Gradient echo NMR imaging is a useful noninvasive technique for the detection, localization and estimation of regurgitant flow in cardiac valve prostheses. However, because transesophageal echocardiography is less time-consuming and less expensive, gradient echo NMR imaging is unlikely to displace transesophageal echocardiography and should be used only in the occasional patient who cannot be adequately imaged by echocardiography.

Doppler versus contrast echocardiography for diagnosis of tricuspid regurgitation.

Sixty-eight patients (mean age 49 years) were studied with contrast echocardiography (CE) and Doppler echocardiography (DE) to evaluate both methods for detecting and grading tricuspid regurgitation (TR). In all patients, right ventricular (RV) angiography was performed. The severity of TR was graded on a 4-point scale. Only 68 of 88 patients who underwent RV angiography (77%) could be evaluated, but 65 of 68 patients who underwent CE (96%) and all 68 who underwent DE (100%) could be evaluated. TR was present in 33 patients as seen on RV angiography. CE and DE correctly diagnosed 27 and 30 patients, respectively, corresponding to a sensitivity of 82% for CE and 91% for DE. Specificity was 100% for CE and 86% for DE. CE and DE grading, respectively, of TR vs RV angiographic grading showed no difference in 50 and 47 patients, a 1-level difference in 8 and 13 and a 2-level difference in 7 and 5 cases. (CE-RV angiography, r = 0.84, p less than 0.001; DE-RV angiography, r = 0.82, p less than 0.001). Thus, CE and DE are accurate methods for routine diagnosis of TR, with DE having higher sensitivity and easier grading. Considering the possibility of false-positive findings of our standard RV angiography, sensitivity and specificity of CE and DE could be even higher.

Failure of radiotherapy to resolve fatal lung damage due to paraquat poisoning.

The most effective treatment of severe paraquat poisoning in man is uncertain. In order to prevent pulmonary fibrosis, we employed radiotherapy of both lungs in a 23-year-old patient with severe paraquat poisoning; however, it failed to prevent the fatal outcome.

Left ventricular geometry and function before and after mitral valve replacement.

Left ventricular geometry and function were assessed in 20 patients with mitral stenosis (MS) and in another 20 patients with mitral insufficiency (MI) five days before and 12 days after mitral valve replacement by transthoracic (TTE) and transesophageal (TEE) echocardiography, as well as late postoperatively (mean: 194 days) by TTE. The continuity of the subvalvular apparatus could not be preserved in any of these patients. In mitral stenosis the area ejection fraction (AEF) in the short axis of the left ventricle (LV) did not change significantly early or late postoperatively. There was a significant lengthening of the left ventricular longitudinal axis in the apical four chamber view whereas the transverse axis remained unchanged. This was likely the result of the discontinuity between the mitral valve and the papillary muscles. AEF and ejection fraction (EF) determined in the four chamber view showed a slight tendency to decrease in the postoperative phase. Patients with mitral insufficiency likewise showed a significant increase of the LV longitudinal diameter postoperatively. In the short axis of the left ventricle and in the apical four chamber view a significant reduction of the AEF was observed. Furthermore, left ventricular EF dropped significantly postoperatively. This decrease was caused by the extension of the LV longitudinal axis accompanied by an enlargement of the transverse diameter as well as by an afterload increase, and a masked impairment of left ventricular function preoperatively. Wall motion analysis of the LV in both groups documented new postoperative hypokinesis especially in the septal segments. At late postoperative examination the hypokinesis disappeared in about 50% of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Size matters more than chemistry for cloud-nucleating ability of aerosol particles.

Size-resolved cloud condensation nuclei (CCN) spectra measured for various aerosol types at a non-urban site in Germany showed that CCN concentrations are mainly determined by the aerosol number size distribution. Distinct variations of CCN activation with particle chemical composition were observed but played a secondary role. When the temporal variation of chemical effects on CCN activation is neglected, variation in the size distribution alone explains 84 to 96% of the variation in CCN concentrations. Understanding that particles' ability to act as CCN is largely controlled by aerosol size rather than composition greatly facilitates the treatment of aerosol effects on cloud physics in regional and global models.

[Possibilities and limits of quantitative analyses using Doppler echocardiography]. / Möglichkeiten und Grenzen quantitativer Analysen mittels der Doppler-Echokardiographie.

Blood flow velocities can be quantified using Doppler echocardiography if the angle is known. Systolic ventricular function can be evaluated by stroke-volume measurement (product of blood flow velocity over time), but individual data may depart significantly from invasive measurements. Information on the diastolic ventricular function is based on measurements in the ventricular inflow tract. These parameters are very sensitive, but not specific at all. The quantification of valvular stenosis is the domain of Doppler echocardiography. Pressure gradients can be obtained from the degree of the blood flow acceleration. The calculated valve area in aortic stenosis using the continuity equation and in AV-valvular stenosis using pressure half-time measurements renders reliable, valuable, and clinically relevant information which is quite independent of cardiac output and additional valvular regurgitations. However, a detailed knowledge about the potential impact on the acquired data due to the specific methodology, the investigator, and the individual patient is mandatory. Out of the Doppler-derived intraventricular pressure indices, the determination of the systolic right ventricular and pulmonary artery pressures in patients with tricuspid regurgitation is widely accepted and has clinical implications. Several semiquantitative procedures to evaluate regurgitant volumes have been developed, at present, however, a definite and reliable quantification is not possible.

[Doppler echocardiography analysis of left ventricular inflow patterns in hypertrophic obstructive cardiomyopathy pre- and postoperatively]. / Dopplerechokardiographische Analyse des linksventrikulären Einflussverhaltens bei hypertrophischer obstruktiver Kardiomyopathie prä- und postoperativ.

The aim of the present study was to assess abnormalities of left ventricular filling by Doppler echocardiography in patients with hypertrophic obstructive cardiomyopathy and to investigate whether a myectomy, in addition to normalizing flow, also improves diastolic function. In part A of the study, 40 patients with diagnosed invasive HOCM (29 patients with a gradient at rest, 11 patients with a gradient only after provocation) were compared with 20 normal subjects. The blood flow in the left ventricular inflow tract was examined by means of Doppler echocardiography. At the same time the isovolumic relaxation (IVR) period and the mitral valve opening area (MVOA) were determined using M-mode and the two-dimensional echocardiography, respectively. In part B of the study, 17 patients were examined directly preoperatively and again postoperatively (mean 14 days). Nine patients were then examined at a later date (mean 8.6 months).(ABSTRACT TRUNCATED AT 250 WORDS)

[Echocardiographic follow-up in latent cardiomyopathy]. / Echokardiographische Verlaufsbeobachtung bei latenter Kardiomyopathie).

Follow-up studies of left ventricular dimensions and function in latent cardiomyopathy (LCM) (as defined by abnormal left ventricular function during exercise in otherwise "normal" heart) have not yet been published. 36 patients with normal left ventricular data at rest (echocardiography, left ventricular angiography, coronary angiography, pulmonary artery pressure), but at least one pathologic function parameter during exercise, were studied prospectively by clinical means and by one- and two-dimensional echocardiography (mean follow-up 3.3 +/- 1.3 years). No patients died. The mean clinical class remained unchanged. The echocardiogram did not reveal an increase of left ventricular end-diastolic dimensions in any case. On average the end-systolic diameter of the left ventricle and shortening fraction in the M-mode echocardiogram did not change either. However, in 5 out of 9 patients with left bundle branch block the 2D-echocardiogram showed the development of a slight reduction of left ventricular contractions (without an increase in the end-diastolic dimensions). This was not to be observed in any patient without LBBB. Another finding was that the dimensions of the left atrium of LCM patients exceeded those of a group of normal subjects (p less than 0.02) with a further increase in the course of the disease (p less than 0.001). Thus, regarding the follow-up of patients with LCM without LBBB, there is no indication of any increase in the size of the left ventricle or reduction of its contractions at rest (mean follow-up 3.3 years). However, our results seem to underline the suspicion of a deterioration in left ventricular function of patients with LBBB.

[A new Doppler echocardiography parameter of diastolic ventricular function]. / Ein neuer dopplerechokardiographischer Parameter der diastolischen Ventrikelfunktion.

The evaluation of flow velocities in left ventricular inflow tract (LVIT) by Doppler echocardiography gives information about the diastolic ventricular function. In late diastole, shortly after the flow velocity of atrial contraction V(A), we notice in the left ventricular outflow tract (LVOT) a laminar flow velocity directed to the aortic valve. The purpose of this study was to compare this flow velocity V(A*) in the LVOT with the flow velocity of the atrial contraction V(A), and the flow velocity of early diastole V(E) in LVIT, to determine whether such comparison would provide information concerning diastolic function. We studied three groups: 39 patients with left ventricular hypertrophy (HY) (mean age 56 +/- 12 y, 77% male), 41 patients with coronary heart disease (KHK) (mean age 53 +/- 10 y, 85% male) and 41 healthy subjects (N) (mean age 50 +/- 16 y, 51% male); all three groups were studied by pulsed Doppler from apical 4 chamber view in LVOT for maximal velocity (Vmax-A*) and time velocity integral of A* (TVI-A*), and in LVIT for maximal velocity of early diastole (Vmax-E), maximal velocity of atrial contraction (Vmax-A), ratio Vmax-E/Vmax-A, and the time velocity integrals (TVI-E, TVI-A). A slight correlation between Vmax-A* and Vmax-A was found (r = .60), being nearly the same as for TVI-A* and TVI-A (r = .64).(ABSTRACT TRUNCATED AT 250 WORDS)

[Pulmonary oedema as a complication of tocolytic therapy (author's transl)]. / Lungenödem als Tokolyse-Komplikation.

Tocolytic treatment with fenoterol and additional administration of betamethasone and acetyl salicylic acid to a 19-year-old girl caused irreversible and finally fatal pulmonary changes. The clinical course in this and that of other published cases indicates a causal relationship between the tocolytic treatment and the onset of pulmonary oedema. The pulmonary arterial pressures in this patient, the poor therapeutic response and the shock-lung picture without corresponding myocardial changes suggest a non-cardiogenic cause of pulmonary oedema. Any of the three drugs administered could have been responsible.

[Infectious endocarditis in hypertrophic obstructive cardiomyopathy]. / Infektiöse Endokarditis bei HOCM.

Clinical and pathological findings in a 37-year-old female patient with HOCM and infective endocarditis of the aortal and mitral valves were reported. The patient died of septic shock. Infective endocarditis with acute insufficiency of the aortal and/or mitral valves is a severe complication in patients with HOCM, because the left ventricle with a disturbed compliance is unable to compensate the acute volume overload. The standard use of nitrates for congestive lung failure and catecholamines for septic shock is problematic. As with other valvular heart diseases, preventive treatment for infective endocarditis is also recommended for patients with HOCM. In the case of acute endocarditis combined with HOCM early surgical intervention must be discussed.

[Clinical significance of Doppler echocardiographic determination of the severity of aortic valve stenoses]. / Klinische Bedeutung der dopplerechokardiographischen Bestimmung des Schweregrades von Aortenklappenstenosen.

The purpose of the study was to evaluate the clinical significance of Doppler echocardiography in the determination of the severity of aortic stenosis, in particular, to determine to what extent a therapeutic decision in the individual patient is possible solely on the basis of noninvasive investigations. Forty consecutive patients (mean age 53 +/- 13 years, 58% males) with suspected aortic valve disease of purely or mainly stenotic nature, were examined by two-dimensional echocardiography and continuous-wave Doppler echocardiography on average 48 h before cardiac catheterization. An adequate Doppler registration was obtained in 93% (37/40). In 59% the right sternal border proved to be the best window. The gradient determined in the Doppler examination correlated well with the maximum catheter gradient (r = 0.95; SYX +/- 6.2 mm Hg; p less than 0.0005) and with the peak-to-peak catheter gradient (r = 0.93; SYX +/- 6.0 mm Hg; p less than 0.0005). However, in the individual case, clinical assessment on the basis of the Doppler gradient alone proved to be misleading. This was the case in early systolic gradients (aortic incompetence, high cardiac output) or in pronounced left ventricular dysfunction. However, additional consideration of the ratio time to peak velocity (Vmax)/left ventricular ejection time (LVET) (criterion for operation greater than 0.35) and of the echocardiographically determined ejection fraction, enabled us to make the same therapeutic decision in all 37 patients (17 conservative, 20 operative) as that made following the result of cardiac catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical course of 470 patients with mitral valve prolapse]. / Klinischer Verlauf bei 470 Patienten mit Mitralklappenprolaps.

The clinical relevance of the echocardiographic finding of mitral valve prolapse (MVP) is largely unclear. Therefore we made a prospective study of 470 patients with MVP established by M-mode echocardiography (63.7% holosystolic, 36.3% late systolic) over an average period of 2.7 years, corresponding to an observation period of 1,269 patient years. Patients with hemodynamically relevant mitral insufficiency were excluded from the study, as were patients with additional cardiac disorders. Three patients died, two of non-cardiac causes, but one probably in sudden cardiac death. 54.8% complained of angina pectoris, 15.6% of dyspnea. 14.4% suffered from non-orthostatic vertigo. 23.3% had one or more syncopes, 14.9% for the first time during the period of observation. 43.4% suffered from rhythm disturbances, 10.2% for the first time during the period of observation. Patients with rhythm disturbances experienced non-orthostatic vertigo (p less than 0.01) and syncopes (p less than 0.01) more frequently than patients without rhythm disturbances. During the study none of the patients developed endocarditis and none had an arterial embolism. Patients with late systolic MVP and a click experienced syncopes more frequently than those with holosystolic MVP without a click (p less than 0.05). Further correlations between the echocardiographic picture, auscultatory findings, age, sex and weight on the one hand and clinical progress on the other hand, were not found. Thus prognosis for MVP with regard to survival seems to be good. Nonetheless, complaints, even potentially threatening syncopes, are frequent. Neither clinical nor echocardiographic findings permit a prognostic statement.

[Doppler echocardiography normal values in various types of mitral valve prostheses]. / Dopplerechokardiographische Normwerte für verschiedene Mitralprothesentypen.

To determine the value of Doppler echocardiography for the normal clinical use in functional diagnostics of prosthetic mitral valves, and to determine normal values for different types of prosthetic valves, 136 patients with different types of prosthetic mitral valves with the same external diameter (29 mm) were examined. For pressure half-time (t1/2) there were higher values for Starr-Edwards (SE) (n = 18) and Lillehei-Kaster (LK) prostheses (n = 10) (113 +/- 29 and 125 +/- 29 ms) than for Saint Jude-Medical (SJM) (n = 56), Björk-Shiley (BS) (n = 40) and Ionescu-Shiley valves (IS) (n = 12) (78 +/- 16, 82 +/- 17 and 93 +/- 28 ms, p less than 0.001), as well as for the orifice and for the mean diastolic gradient (delta p). The upper permissible limits of t1/2 and delta p were 104 ms and 4.1 mm Hg for SJM, and 111 and 4.8 for BS valves respectively. Day-to-day variability (n = 30) was 5.0% (0.0-14.4%, if t1/2 greater than 100 ms: 0.0-6.0%), the correlation was r = 0.97. The duration of implantation did not have any influence on prosthetic mitral valve function. These normal values and limits form a basis for the evaluation of prosthetic mitral valves in the future.

Changes of the degree of hypertrophy in hypertrophic obstructive cardiomyopathy under medical and surgical treatment.

The aim of our study was to establish the extent to which therapy of hypertrophic obstructive cardiomyopathy (HOCM) can influence the degree of hypertrophy. By means of two-dimensionally guided M-mode echocardiography, 120 patients with HOCM (age range 4-72 years, mean age 41 years) were observed over an average period of 49 +/- 41 months. Depending on the respective therapy, we formed four patient groups: group 1: 13 patients without any therapy (follow-up period 31 +/- 30 months); group 2: 27 patients receiving propranolol (follow-up period 47 +/- 34 months); group 3: 50 patients receiving verapamil (follow-up period 39 +/- 27 months), and group 4: 30 patients with myectomy (follow-up period 34 +/- 32 months). In group 4, as expected, the thickness of the interventricular septum (IVS) decreased postoperatively (from 24.2 +/- 4.5 to 19.8 +/- 6.7 mm, p less than 0.05), and the left ventricular posterior wall (LVPW) thickness also decreased later postoperatively (from 13.0 +/- 2.6 to 11.9 +/- 2.3 mm, p less than 0.05). The left ventricular diameters increased. In groups 2 and 3 treated with pharmacotherapy as in the untreated patients of group 1, on average there was no change in IVS and LVPW thickness nor in the left ventricular diameters (with the exception of increasing left ventricular end-diastolic diameter in the propranolol-treated group). In contrast to group 1, in occasional cases there were substantial decreases of IVS thickness (11% of the patients in group 2, 13% in group 3) or LVPW thickness (13% of the patients in group 2, 12% in group 3).(ABSTRACT TRUNCATED AT 250 WORDS)