Balloon Test Occlusion with the Doppler Velocity Guidewire.
ABSTRACT Transcranial Doppler ultrasonography is the most commonly used method of cerebrovascular blood flow velocity measurement, but it is subject to certain technical and anatomic limitations. The Doppler velocity guidewire measures blood flow velocity within any vessel during cerebral angiography, overcoming these limitations. We report the first use of this guidewire in the measurement of blood flow velocity during balloon test occlusion, with results similar to simultaneously measured transcranial Doppler ultrasonography. Velocity measurement by Doppler guidewire could be useful in balloon test occlusion for vertebrobasilar circulation, where transcranial Doppler ultrasonography is limited, and provide anatomically specific blood flow velocity measurements in the diagnosis and treatment of stroke and other cerebrovascular diseases.
- Bioscience Biotechnology and Biochemistry - BIOSCI BIOTECHNOL BIOCHEM. 01/1993; 57(2):322-324.
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ABSTRACT: Snow molds are a group of fungi that attack dormant plants under snow. In this paper, their survival strategies are illustrated with regard to adaptation to the unique environment under snow. Snow molds consist of diverse taxonomic groups and are divided into obligate and facultative fungi. Obligate snow molds exclusively prevail during winter with or without snow, whereas facultative snow molds can thrive even in the growing season of plants. Snow molds grow at low temperatures in habitats where antagonists are practically absent, and host plants deteriorate due to inhibited photosynthesis under snow. These features characterize snow molds as opportunistic parasites. The environment under snow represents a habitat where resources available are limited. There are two contrasting strategies for resource utilization, i.e., individualisms and collectivism. Freeze tolerance is also critical for them to survive freezing temperatures, and several mechanisms are illustrated. Finally, strategies to cope with annual fluctuations in snow cover are discussed in terms of predictability of the habitat.Microbes and Environments 01/2009; 24(1):14-20. · 2.44 Impact Factor
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ABSTRACT: The study of carbohydrate metabolism in perennial ryegrass (Lolium perenne L. cv. Bravo) during the first 48 h of regrowth showed that fructans from elongating leaf bases were hydrolysed first whereas fructans in mature leaf sheaths were degraded only after a lag of 1.5 h. In elongating leaf bases, the decline in fructan content occurred not only in the differentiation zone (30-60 mm from the leaf base), but also in the growth zone. Unlike other soluble carbohydrates, the net deposition rate of fructose remained positive and even rose during the first day following defoliation. The activity of fructan exohydrolase (FEH; EC 126.96.36.199) was maximal in the differentiation zone before defoliation and increased in all segments, but peaked in the growth zone after defoliation. These data strongly indicate that fructans stored in the leaf growth zone were hydrolysed and recycled in that zone to sustain the refoliation immediately after defoliation. Despite the depletion of carbohydrates, leaves of defoliated plants elongated at a significantly higher rate than those of undefoliated plants, during the first 10 h of regrowth. This can be partly attributed to the transient increase in water and nitrate deposition rate. The results are discussed in relation to defoliation tolerance.Planta 06/2001; 213(1):109-20. · 3.35 Impact Factor