Habitat selection according to the ability of animals to eat, digest and detoxify foods

Large herbivores play a major role in shaping vegetation community dynamics through selective consumption of particular plants and plant communities. An understanding of the factors influencing diet selection at the level of individual bites ('bite scale') is important for prediction of the impact of herbivores on vegetation at the habitat scale. Bite-scale diet selection represents an integration of the twin goals of maximizing nutrient intake and minimizing toxin intake. Recent research with ruminants in pen-fed situations has shown that animals are able to make choices between artificial foods that maximize growth and other production variables. The role of post-ingestive feedback as an important mechanism for allowing animals to assess the nutritional quality of particular foods, and so select optimal diets, has been recognized in a number of recent experiments. Our understanding of the role of toxin intake minimization in diet selection decisions is more rudimentary. An important advance in the last decade has been the acknowledgement of the role of post-ingestive feedback and learning as a mechanism for avoidance of dietary toxicity. Further research is required to assess the importance of these processes in relation to free-grazing animals. The extent to which an understanding of bite-scale diet selection can be used to predict habitat utilization is not well understood. At the habitat scale additional factors such as predator avoidance, social constraints, avoidance of parasitism and microclimatic effects have an important influence on foraging decisions. Future research needs to focus on developing a quantitative understanding of such decisions at the habitat scale.

I smell a rat!

This is a case history with a difference. The year was 1938 and the story was told to one of us in 1946 by Henry Cohen (HC), then Professor of Medicine at Liverpool (Figure 1). Bothdiagnosis and successful treatment were made in the patient's home without any of the customary investigations. The case is reported because it still provides lessons: there are no substitutes for wide-ranging knowledge and its thorough clinical application

Effective clinical policies in a district general hospital

Effective clinical practice in a hospital needs current knowledge together with the skills and right attitude; these should be applied continuously. Failure of this system can be due to ignorance or arrogance. We attempted to correct these deficiencies by formulating a set of policies which were enforced from 1962 to 1983. The policies related to the following: intensive care (including asthma, nutrition and organ donation), drug prescribing and resuscitation. We believe that these rules improved patient care and the standards of training; the prescribing policy also saved money.

The evolution and nursing history of a general intensive care unit (1962-1983)

In this paper we have reviewed the origin and evolution of Whiston Hospital's General Intensive Care Unit (ICU) from its humble beginnings as an offshoot of a general ward in the early 1960s. The length of service of the senior nursing staff over a period of 21 years was also calculated. The average duration of service was 16.5 years--a figure which significantly surpassed those quoted in the literature. In addition, we have outlined the development of nurse training in intensive care as well as the role of the nurses in research in the ICU. The question as to whether later college-based training was superior to the previous hospital-based course remained unanswered.

The influence of sexual dimorphism in body size and mouth morphology on diet selection and sexual segregation in cervids

In mammals patterns of food resource distribution influence female distribution, leading to aggregation and favouring the evolution of a polygynous mating system. Under polygyny, sexual selection favours an increase of the male body size, since larger bodied males have competitive advantage in fights for mates. As a result, sexual body size dimorphism is a general rule in polygynous artiodactyls and is correlated with the degree of polygyny. Sex differences in body size lead to differences in energy requirements and food selection between the sexes. This has led to the sexual size dimorphism hypothesis being used to explain sexual segregation in ungulates, although from the available studies, it is not possible to deduce a consistent pattern between sexes in the use of forage of different abundance or quality. Two other groups of hypotheses have been put forward to explain sexual segregation in ungulates. These are based on reproductive strategy and social factors, both of which are independent of body size. The mechanistic explanation for differences in food selection ability and intake rate between animals of different body size and how this can lead to an understanding of the sex differences in diet and sexual segregation, both of which are intimately linked, is discussed.

The adaptive significance of reproductive strategies in ungulates

We examine the relation between litter size, gestation length, neonate mass and growth rate among ungulates. By using a recent method for analysing comparative data, we show that ungulates can be divided along a slow-fast continuum, even after accounting for the effects of maternal body mass and common ancestry. Some species produce many small offspring during a short period, whereas others take a long time to raise a single large offspring. These differences in life-history strategy are associated with diet, i.e. browsers have relatively larger litters and smaller neonates than grazers.

Circumflex retroesophageal right aortic arch simulating mediastinal tumor or dissecting aneurysm

The authors present three cases of circumflex right aortic arch, a retroesophageal arch in which the aorta crosses from right to left behind the esophagus to descend on the left side. The findings on the frontal chest films resembled those of a left arch with mediastinal widening, simulating a mass. Aortography revealed four-vessel branching of the arch vessels, typical of right aortic arch with aberrant left subclavian artery. Computed tomography and barium studies of the esophagus demonstrated the retroesophageal course of the aorta. In two patients, obstruction of the thoracic portion of the left subclavian artery resulted in differences in blood pressure and pulse between the arms, supporting the clinical impression of dissecting aortic aneurysm.

An index to predict outcome in adult respiratory distress syndrome

Thirty patients with adult respiratory distress syndrome required intermittent positive pressure ventilation; 15 survived. In 25 the syndrome followed bacterial infection or multiple injuries. From the peak upper airway pressure, the oxygen gradient and the age of the patient, an index was obtained which discriminated between the survivors and those who died from the pulmonary lesion of the syndrome.

Algorithm for modified alkaline diuresis in salicylate poisoning

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A comparison of Iohexol and Conray-60 in peripheral angiography

A double-blind clinical trial was performed in 61 adults in an attempt to compare the safety and efficacy of an ionic with a nonionic contrast agent in peripheral angiography. Objective clinical (vital signs) and laboratory factors (complete blood count, serum electrolytes, serum chemistry, urinalysis, and urine chemistry) were monitored before, during, and after the examination on each patient. There was no statistically significant difference in pre- and posttest laboratory and clinical parameters between those patients who received ionic and those who received nonionic contrast material. Data also were collected to evaluate pain and radiographic quality. The most striking finding was the marked diminution of perceived pain in those patients who received nonionic contrast material compared with those who did not. The data suggest that nonionic contrast agents are at least as safe as the ionic agents currently in use and produce an examination of equal quality with considerably less patient discomfort.

Transcatheter vascular occlusion therapy with isobutyl 2-cyanoacrylate (bucrylate) for control of massive upper-gastrointestinal bleeding

Transcatheter embolization with bucrylate, a tissue adhesive, was performed in 16 patients with massive upper-gastrointestinal bleeding. Control of arterial bleeding from the stomach was achieved in 6 of 8 patients, and from the duodenum in 3 of 4. Embolization of gastric veins resulted in temporary control of esophageal variceal bleeding in 3 of 4 patients. Histological study showed no evidence of bucrylate causing histotoxicity in 2 patients. Because bucrylate polymerizes rapidly, a localized vascular occlusion mimicking a surgical ligation is produced. Because collateral vessels are not occluded. localized tissue ischemia is unlikely. Tissue adhesives are, however, difficult to use.

The transjugular technique of hepatic venography and biopsy, cholangiography, and obliteration of esophageal varices

The transjugular technique facilitates various diagnostic and therapeutic procedures in the liver. Even in patients with defective hemostasis, severe ascites, or marked obesity, liver biopsy or cholangiography can be performed with relative safety. It also provides an alternative route for entry into the portal system.

Intra-arterial lidocaine: an effective analgesic for peripheral angiography

Intra-arterial lidocaine was found to be an effective and safe method for reducing pain associated with peripheral angiography. A convenient method for delivery is to directly mix 2% lidocaine and contrast material in a ratio of 1:10 by volume. In a comparative evaluation, 25 of 29 patients experienced significantly less discomfort when the lidocaine-contrast mixture was used as compared to contrast material alone. There were no apparent complications from the use of intra-arterial lidocaine.

The traumatic pneumomyelogram. A previously undescribed entity

Air within the cervical subarachnoid space secondary to skull trauma (traumatic air myelogram or pneumomyelogram) has not been reported previously. Such a case is presented and the findings are reviewed in the light of existing literature.