The purpose of this retrospective study was to determine the prevalence of alcoholism among terminally ill cancer patients when assessed by multidisciplinary interviews and by the CAGE Questionnaire. We reviewed the charts of 100 consecutive patients assessed by a multidisciplinary team for the presence of alcoholism during 1989, and 100 consecutive patients assessed by the CAGE Questionnaire during 1992. Alcoholism was diagnosed in 28/100 patients during 1989 (28%) and 18/66 patients during 1992 (27%). Thirty-four patients were unable to complete the CAGE Questionnaire in 1992 because of sedation or cognitive impairment; six of these patients (17%) were found to be alcoholics after multidisciplinary assessment. Only 9/28 (32%) and 8/24 (33%) patients diagnosed as alcoholics during 1989 and 1992, respectively, had been previously diagnosed as alcoholics according to the medical charts. The mean equivalent daily dose of morphine during admission and on Day 2 during 1992 were 153 +/- 193 mg and 183 +/- 198 for alcoholic patients, versus 58 +/- 80 and 70 +/- 79 mg for nonalcoholics (P = 0.06 and 0.03, respectively). The maximal dose of opioid and the pain intensity during admission, however, were not significantly different between alcoholics and nonalcoholics. Our results suggest that alcoholism is highly prevalent and underdiagnosed among symptomatic terminally ill cancer patients. The CAGE Questionnaire should be used for screening for alcoholism in this population. When multidimensional assessment and management of pain is applied, the outcome of alcoholic patients appears to be similar to that of nonalcoholics.
The purpose of this retrospective study is to assess the frequency and intensity of chronic nausea in patients admitted to the Palliative Care Unit and the results of a metoclopramide-based treatment regimen. We reviewed the medical records of 100 consecutive patients admitted to the Palliative Care Unit at the Edmonton General Hospital until death during 1992-1993. All patients had terminal cancer and normal cognitive function. All patients completed the Functional Analogue Scale for appetite, nausea, pain, activity, shortness of breath, and sensation of well-being at 1000 and 1600 hours every day. Patients who complained of nausea initially received metoclopramide 10 mg every 4 hr orally or subcutaneously (Step 1). If nausea persisted, dexamethasone 10 mg twice daily was added (Step 2). Step 3 consisted of a continuous subcutaneous infusion of metoclopramide of 60-120 mg/day plus dexamethasone. If no response was observed, other antiemetics were administered (Step 4). Upon admission to the unit, 32 patients (32%) presented with nausea. During the average admission of 25 +/- 13 days, 98 patients (98%) developed nausea. Twenty-five patients (25%) required other antiemetics because of bowel obstruction (18), extrapyramidal side effects (3), or other reasons (4). Most patients without bowel obstruction achieved excellent control of nausea using the metoclopramide-based regimen. During the first 5 days and last 5 days of admission, nausea had significantly lower intensity than the rest of the symptoms that were monitored. Our results suggest that, although nausea is very frequent, it can be well controlled in the majority of patients using safe and simple antiemetic regimens.
A rise in temperature will intensify the feeding links involving ectotherms in food webs. However, it is unclear how the effects will quantitatively differ between the plant-herbivore and herbivore-carnivore interface. To test how warming could differentially affect rates of herbivory and carnivory, we studied trophic interaction strength in a food chain comprised of green algae, herbivorous rotifers and carnivorous rotifers at 10, 15, 20 and 25°C. We found significant warming-induced changes in feeding by both herbivorous and carnivorous rotifers, but these responses occurred at different parts of the entire temperature gradient. The strongest response of the per capita herbivore's ingestion rate occurred due to an increase in temperature from 15 to 20°C (1.9 fold: from 834 to 1611 algal cells per h−1) and of the per capita carnivore's ingestion rate from 20 to 25°C (1.6 fold: from 1.5 to 2.5 prey h−1). Handling time, an important component of a consumer's functional response, significantly decreased from 15 to 20°C in herbivorous rotifers. In contrast, it decreased from 20 to 25°C in carnivorous rotifers. Attack rates significantly and strongly increased from 10 to 25°C in the herbivorous animals, but not at all in the carnivores. Our results exemplify how the relative forces of top-down control exerted by herbivores and carnivores may strongly shift under global warming. But warming, and its magnitude, are not the only issue: If our results would prove to be representative, shifts in ectotherm interactions will quantitatively differ when a 5°C increase starts out from a low, intermediate or high initial temperature. This would imply that warming could have different effects on the relative forces of carnivory and herbivory in habitats differing in average temperature, as would exist at different altitudes and latitudes.
Climate change will alter the forces of predation and competition in temperate ectotherm food webs. This may increase local extinction rates, change the fate of invasions and impede species reintroductions into communities. Invasion success could be modulated by traits (e.g., defenses) and adaptations to climate. We studied how different temperatures affect the time until extinction of species, using bitrophic and tritrophic planktonic food webs to evaluate the relative importance of predatory overexploitation and competitive exclusion, at 15 and 25 °C. In addition, we tested how inclusion of a subtropical as opposed to a temperate strain in this model food web affects times until extinction. Further, we studied the invasion success of the temperate rotifer Brachionus calyciflorus into the planktonic food web at 15 and 25 °C on five consecutive introduction dates, during which the relative forces of predation and competition differed. A higher temperature dramatically shortened times until extinction of all herbivore species due to carnivorous overexploitation in tritrophic systems. Surprisingly, warming did not increase rates of competitive exclusion among the tested herbivore species in bitrophic communities. Including a subtropical herbivore strain reduced top-down control by the carnivore at high temperature. Invasion attempts of temperate B. calyciflorus into the food web always succeeded at 15 °C, but consistently failed at 25 °C due to voracious overexploitation by the carnivore. Pre-induction of defenses (spines) in B. calyciflorus before the invasion attempt did not change its invasion success at the high temperature. We conclude that high temperatures may promote local extinctions in temperate ectotherms and reduce their chances of successful recovery.
Summary 1. It is increasingly realised that aquatic and terrestrial systems are closely linked. We investigated stable isotope variations in Odonata species, putative prey and basal resources of aquatic and terrestrial systems of northern Mongolia during summer. 2. In permanent ponds, δ13C values of Odonata larvae were distinctly lower than those of putative prey, suggesting that body tissue comprised largely of carbon originating from isotopically light carbon sources. Presumably, prey consumed during autumn and winter when carbon is internally recycled and/or methanotrophic bacteria form an important basal resource of the food web. In contrast, in a temporary pond, δ13C values of Odonata larvae were similar to those of putative prey, indicating that their body carbon originated mainly from prey species present. 3. Changes in δ15N and δ13C values between larvae and adults were species specific and reflected differential replacement of the larval isotopic signature by the terrestrial diet of adult Odonata. The replacement was more pronounced in Odonata species of permanent ponds than in those of the temporary pond, where larvae hatched later in the year. Replacement of larval carbon varied between tissues, with wings representing the larval isotopic signature whereas thoracic muscles and eggs reflected the δ15N and δ13C values of the terrestrial diet of adults. 4. The results suggest that because of their long larval development, Odonata species of permanent ponds carry the larval signature, which is partly replaced during their terrestrial life. Terrestrial prey forms the basis for egg production and thus the next generation of aquatic larvae. In temporary ponds, in contrast, Odonata species rely on prey from a single season, engage in a prolonged aquatic phase and hatch later, leaving less time to acquire terrestrial prey resources for offspring production. Stable isotope analysis provided important insights into the food webs of the waterbodies and their relationship to the terrestrial system.
Climate forecasts project further increases in extremely high-temperature events. These present threats to biodiversity, as they promote population declines and local species extinctions. This implies that ecological communities will need to rely more strongly on recovery processes, such as recolonization from a meta-community context. It is poorly understood how differences in extreme event intensity change the outcome of subsequent community reassembly and if such extremes modify the biotic environment in ways that would prevent the successful re-establishment of lost species. We studied replicated aquatic communities consisting of algae and herbivorous rotifers in a design that involved a control and two different heat wave intensity treatments (29°C and 39°C). Animal species that suffered heat-induced extinction were subsequently re-introduced at the same time and density, in each of the two treatments. The 39°C treatment led to community closure in all replicates, meaning that a previously successful herbivore species could not re-establish itself in the postheat wave community. In contrast, such closure never occurred after a 29°C event. Heat wave intensity determined the number of herbivore extinctions and strongly affected algal relative abundances. Re-introduced herbivore species were thus confronted with significantly different food environments. This ecological legacy generated by heat wave intensity led to differences in the failure or success of herbivore species re-introductions. Reassembly was significantly more variable, and hence less predictable, after an extreme heat wave, and was more canalized after a moderate one. Our results pertain to relatively simple communities, but they suggest that ecological legacies introduced by extremely high-temperature events may change subsequent ecological recovery and even prevent the successful re-establishment of lost species. Knowing the processes promoting and preventing ecological recovery is crucial to the success of species re-introduction programs and to our ability to restore ecosystems damaged by environmental extremes.
The Pleistocene glaciations shaped the distribution and population structure of most European species. Some species survived the glacial cycles by shifting their range to Mediterranean refuges, while others endured in central European habitats. It has been argued that certain cold‐tolerant aquatic insect populations were able to persist in non‐freezing rivers close to glaciers. We aimed to identify the Pleistocene biogeographic history of a net‐winged midge (Blephariceridae), a relatively unknown group of Dipteran montane habitat specialists, by inference from its current population genetic structure. We sampled five mountain ranges covering the extent of the species range. We genotyped a novel set of 11 microsatellites and sequenced the mitochondrial cytochrome‐c‐oxidase subunit I region to detect genetic structure within and among five European mountain ranges in the net‐winged midge Liponeura cinerascens cinerascens. Liponeura cinerascens cinerascens shows distinct genetic differentiation between different mountain ranges, coupled, however, with near panmictic gene flow across distances exceeding 100 km within each studied mountain range. Distinct mitochondrial cytochrome‐c‐oxidase subunit I lineages with endemic haplotypes, microsatellite population genetic structure and high levels of regionally private alleles provide evidence that mountain range populations have been evolving independently from each other for a significant number of generations. Liponeura cinerascens cinerascens is able to maintain gene flow between watercourses in highly structured mountain ranges. Lowland regions, however, pose significant dispersal barriers, possibly because high‐gradient stretches with boulders are rare in such landscapes. We posit that each of the studied mountain regions represents an independent Pleistocene glacial refuge, and that L. c. cinerascens was able to persist glacial cycles in extra‐Mediterranean periglacial refugia in the Jura Mountains, Bavarian Forest, and Carpathians.
1. Dispersal abilities and the resulting levels of connectivity between streams influence population structure in aquatic organisms. We investigated how different dispersal and life-history traits affect gene flow and population structure in three aquatic invertebrate species in a central European mountain range.2. We used microsatellite markers and mitochondrial cytochrome oxidase I barcode data to assess small-scale population structure and connectivity of the mayfly Baetis alpinus, the stonefly Brachyptera seticornis, and the amphipod Gammarus fossarum in seven streams within Bavarian Forest National Park, Germany. 3. Significant population structure within the study area was detected in B. alpinus and G. fossarum, whereas B. seticornis had signatures of panmixia. In G. fossarum, that structure corresponded to stream topography, while in B. alpinus it did not. The Bavarian Forest range appears to be a contact zone for different mitochondrial lineages of B. alpinus and G. fossarum. 4. Limited geneflow between sample sites in B. alpinus can be explained by the species' short adult lifespans, which restricts dispersal between sites. Since imagines are able to disperse via adult flight population structure is, however, decoupled from stream topology. Longer-lived B. seticornis is better able to maintain geneflow between sample sites. In flightless G. fossarum, population structure corresponding to stream topology can be explained by limited dispersal capabilities between streams. 5. Dispersal ability alone is insufficient to predict or explain patterns of gene flow and connectivity for individual species, and should be examined together with life-history traits when assessing population and community structure.
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