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111.
O. Vainio 《Veterinary anaesthesia and analgesia》1991,18(1):35-37
Ten laboratory beagles pre-medicated with medetomidine (40 μg/kg bodyweight [bwt]) were anaesthetised using a rapid injection of propofol, followed by propofol infusion. A loading dose of 4 mg/kg bwt of propofol was administered intravenously (iv) as a bolus and, immediately after, a 60 min iv propofol infusion (150 μg/kg bwt/min) was initiated. After a transient increase, mean arterial blood pressure decreased significantly below the pre-propofol level. However, the lowest values recorded (115 ± 11 mmHg) remained within the physiological limits. Heart rate increased significantly (from 41 ± 7.3 to 58 ± 11 beats/min) after initiation of the propofol infusion. No significant changes were seen in respiratory frequency; pO2 decreased transiently; minimum values (10 ± 2.3 kPa) recorded 5 mins after initiation of the propofol infusion differed significantly from the starting level. pCO2 increased significantly and the highest values recorded were 6.1 ± 0.35 kPa. Accordingly, pH decreased reaching the lowest level (pH 7.29) 15 mins after initiation of the propofol infusion. The analgesic effect of the present combination was not studied, but the absence of the palpebral and pedal reflexes suggested a surgical stage of anaesthesia. Therefore, propofol infusion in beagles pre-medicated with medetomidine proved to be a promising anaesthetic regimen but, if used clinically, oxygen-enriched inspired air should be used. 相似文献
112.
In tropical lowlands, ecosystems with peat strata are commonly reported from Southeast Asia, but hardly at all from Amazonia. In this paper, we quantify the horizontal distribution of four important plant nutrients (Ca, Mg, K and P) in five peatland sites located in Peruvian Amazonia and the vertical distribution of these nutrients in one of the sites. With this data as well as topography measurements of the peat deposit from one of the sites, we showed that minerotrophic and ombrotrophic peatlands can be detected in Amazonian floodplains. The nutrient-poor ombrotrophic bogs receive nutrients only from atmospheric deposition because of their thick peat layer and convex topography, while the minerotrophic swamps are periodically covered by nutrient-rich floodwater and/or receive nutrient input from surface waters or from groundwater with capillary rise. The existence of such peatlands in the Amazonian lowlands increases the regional habitat diversity and availability of palaeoecological information and probably has implications also for the hydrological dynamics, water quality, and carbon dynamics of the area. 相似文献
113.
Forecasts of rapid climate change raise the question how quickly species can evolutionarily adapt to future climates. The adaptability of forest trees to environmental changes is generally promoted by high levels of genetic diversity and gene flow, but it can also be slowed down by long generation times and low mortality of established trees. Here, we investigate the adaptation of Scots pine (Pinus sylvestris) and Silver birch (Betula pendula) to climate change induced prolongation of the thermal growing season. We use quantitative genetic individual-based simulations to disentangle the relative roles of mortality, dispersal ability and maturation age for the speed of adaptation. The simulations predict that after 100 years of climate change, the genotypic growth period length of both species will lag more than 50% behind the climatically determined optimum. This lag is reduced by increased mortality of established trees, whereas earlier maturation and higher dispersal ability had comparatively minor effects. The evolutionary lag behind environmental change shown in our simulations stresses the importance of accounting for evolutionary processes in forecasts of the future dynamics and productivity of forests. Sensitivity of the adaptation speed to mortality suggests that species experiencing high mortality rates as well as populations subject to regular disturbances such as storms or fires might be the quickest to adapt to a warming climate. 相似文献
114.
Outi Karppanen Martti Venäläinen Anni M. Harju Tapio Laakso 《Annals of Forest Science》2008,65(6):610-610
115.
Kuusela E Vainio O Short CE Leppäluoto J Huttunen P Ström S Huju V Valtonen A Raekallio M 《Journal of veterinary pharmacology and therapeutics》2003,26(3):199-204
The effects of propofol infusion were compared with propofol/isoflurane anaesthesia in six beagles premedicated with 10 microg/kg intramuscular (i.m.) dexmedetomidine. The suitability of a cold pressor test (CPT) as a stress stimulus in dogs was also studied. Each dog received isoflurane (end tidal 1.0%, induction with propofol) with and without CPT; propofol (200 microg/kg/min, induction with propofol) with and without CPT; premedication alone with and without CPT in a randomized block study in six separate sessions. Heart rate and arterial blood pressures and gases were monitored. Plasma catecholamine, beta-endorphin and cortisol concentrations were measured. Recovery profile was observed. Blood pressures stayed within normal reference range but the dogs were bradycardic (mean heart rate < 70 bpm). PaCO2 concentration during anaesthesia was higher in the propofol group (mean > 57 mmHg) when compared with isoflurane (mean < 52 mmHg). Recovery times were longer with propofol than when compared with the other treatments. The mean extubation times were 8 +/- 3.4 and 23 +/- 6.3 min after propofol/isoflurane and propofol anaesthesia, respectively. The endocrine stress response was similar in all treatments except for lower adrenaline level after propofol infusion at the end of the recovery period. Cold pressor test produced variable responses and was not a reliable stress stimulus in the present study. Propofol/isoflurane anaesthesia was considered more useful than propofol infusion because of milder degree of respiratory depression and faster recovery. 相似文献
116.