Lessons from the European Cooperative recombinant tissue-type plasminogen activator (rt-PA) versus placebo trial

AbstractA new European Cooperative Study Group trial of 721 patients has recently found recombinant tissue-type plasminogen activator (rt-PA) to positively affect infarct size, ten ventricular function, cardiovascular morbidity and early survival. In this 26 center trial, patients were randomized to receive either placebo or 100 mg rt-PA intravenously over 3 h. Heparin (5,000 U bolus injection and then 1,000 U/h) and aspirin (250 mg initially, then 75 to 125 mg every other day) were given to all patients until angiography was performed (10 to 22 days after allocation).Enzymatic infarct size was found to be 20% smaller in the rt-PA group (2p = 0.0018) than in the control group. At angiography, 83% of rt-PA-treated patients had a patent infarct-relaled vessel compared with 77% of the placebotreated patients. Ejection fraction was 2.2% points higher (2p = 0.04) and end-diastolic and end-systolic volumes were ± 6 ml smaller (2p = 0.003) than in the control group, indicating an improved left ventricular pump function in the thrombolysis group. Cardiovascular complications such as shock, ventricular fibrillation and pericarditis were markedly fewer in patients treated with rt-PA, but bleeding complications occurred more frequently. An intracranial hemorrhage within 3 days after the infusion of rt-PA was observed in five patients (1.4%). None of these bleeding episodes was causally related to death. Although this European Cooperative trial was not designed primarily as a mortality study, important reductions in early mortality rates were observed. At 14 days, the death rate among rt-PA-treatcd patients was 2.8%, which is 51% (95% confidence interval −76% to +1%, 2p = 0.053) lower than the 5.7% mortality rate of the control group. At 3 months, the mortality rate was 5.1% in the rt-PA group, which is 36% (95% confidence interval −63% to +13%, 2p = 0.121) lower than the 7.9% in the control group. In patients treated within 3 h of symptoms, the European Cooperative Study Group reported mortality reductions of 82% (95% confidence interval −95% to −31%, 2p = 0.009) at 14 days and 59% (95% confidence interval −83% to −2%, 2p = 0.045) at 3 months. The early mortality rates observed in this trial were very similar to those reported previously by the same European Cooperative Study Group for a similarly selected and treated group of patients and are the lowest so far published in large trials with intravenously administered thrombolytic agents.The results of these European multicenter trials, together with the recent findings of large studies conducted in the United States (Johns Hopkins Hospital trial, Thrombolysis and Angioplasty in Myocardial Infarction [TAMI], Thrombolysis in Myocardial Infarction [TIMI]), further add to evidence that early thrombolytic treatment with rt-PA in addition to antithrombotic and antiplatelet medication is of major benefit for patients with an acute myocardial infarction

Spatial and temporal patterns of carabid activity-density in cereals do not explain levels of predation on weed seeds

Seed predation is an important component of seed mortality of weeds in agro-ecosystems, but the agronomic use and management of this natural weed suppression is hampered by a lack of insight in the underlying ecological processes. In this paper, we investigate whether and how spatial and temporal variation in activity-density of granivorous ground beetles (Coleoptera: Carabidae) results in a corresponding pattern of seed predation. Activity-density of carabids was measured by using pitfall traps in two organic winter wheat fields from March to July 2004. Predation of seeds (Capsella bursa-pastoris, Lamium amplexicaule, Poa annua and Stellaria media) was assessed using seed cards at the same sites and times. As measured by pitfall traps, carabids were the dominant group of insects that had access to the seed cards. In the field, predation of the four different species of seed was in the order: C. bursa-pastoris>P. annua>S. media>L. amplexicaule; and this order of preference was confirmed in the laboratory using the dominant species of carabid. On average, seed predation was higher in the field interior compared to the edge, whereas catches of carabids were highest near the edge. Weeks with elevated seed predation did not concur with high activity-density of carabids. Thus, patterns of spatial and temporal variation in seed predation were not matched by similar patterns in the abundance of granivorous carabid beetles. The lack of correspondence is ascribed to effects of confounding factors, such as weather, the background density of seeds, the composition of the carabid community, and the phenology and physiological state of the beetles. Our results show that differences in seed loss among weed species may be predicted from laboratory trials on preference. However, predator activity-density, as measured in pitfall traps, is an insufficient predictor of seed predation over time and space within a fiel

Extragalactic line surveys

40 years have passed since the first molecular detection outside our Galaxy. Since then, our knowledge on the distribution, kinematics and composition of the molecular material in the extragalactic ISM has built up significantly based not only on the carbon monoxide observations but also in the more than 50 molecular species detected. In particular, line surveys have been proven to be excellent tools to study the chemical composition in the nuclei of galaxies. Such studies have been favored by the increasing instantaneous bandwidth of current mm and sub-mm facilities. Here I will summarize the highlights of extragalactic molecular spectroscopy, mostly focusing in the results from molecular line surveys published in the last few years as well as the aims of still ongoing projects.Comment: 9 pages, 2 figures, in Proceedings of the 280th Symposium of the International Astronomical Unio

Simple delay monitor for droplet sorters

We have constructed a simple device by which the optimal delay time between optical measurement of a cell and the application of the droplet charging pulse can be determined directly in a flow sorter. The device consists of a stainless steel chamber in which the sorted droplets are collected. In the collection chamber the collected droplets run through a capillary where a continuous fluorescence measurement is made. With a sample of fluorescent particles, the delay time is optimal when the measured fluorescence is maximal. The measuring volume is always filled with the last droplets sorted (about 3,000). With this device, the setting of the delay time can be done in a few seconds without the need for microscopical verification. \ud The fluorescence in the collection chamber is excited and detected via optical fibers using about 10% of the light of the existing laser from the flow cytometer and an extra photomultiplier

Interactions with a photonic crystal micro-cavity using AFM in contact or tapping mode operation

In this paper we show how the evanescent field of a localized mode in a photonic crystal micro-cavity can be perturbed by a nano-sized AFM tip. Due to the high field intensities in the cavity, we can see a significant change in output power when the tip is brought into the evanescent field in either contact or tapping mode operation. We find a 4 dB modulation, when using a $Si_{3}N_{4}$ tip and we show that the transmittance can be tuned from 0.32 to 0.8 by varying the average tapping height

Ecological agriculture in South-India : an agro-economic comparison and study of transition

This report describes two research programmes carried out on ecological agriculture in South-India. Experiences of twelve farmers in transition towards ecological agriculture are described and analysed. The comparative performance of seven farmer pairs, consisting of one ecological and one conventional reference farm, is analysed in relation to agronomic and economic performanc