There are various ways in which data for economic evaluations may be obtained, including via clinical trials and via economic modelling. There are numerous advantages and disadvantages associated with each method, although it is generally assumed that economic models lack the accuracy required for the calculation of meaningful cost-effectiveness data. In order to assess the predictive accuracy of economic modeling in the context of cholesterol-modifying pharmacotherapy it is possible to compare predicted coronary heart disease (CHD) incidence estimates obtained using CHD risk equations derived from the Framingham Heart Study (FHS) with actual CHD incidence rates achieved in a major clinical trial, the West of Scotland Coronary Prevention Study (WOSCOPS). FHS-derived CHD risk equations substantially underestimate the actual risks of nonfatal myocardial infarction obtained by WOSCOPS. However, in predicting risks of death from CHD, FHS-derived CHD risk equations estimate extremely accurately the incidence obtained by WOSCOPS. For example, from WOSCOPS the risk of an individual fulfilling the trial entry criteria incurring nonfatal myocardial infarction or CHD death in 4.9 years is 0.079 for placebo group and 0.055 for the intervention group. Therefore, the relative risk for the intervention group relative to placebo group is 0.696, implying a risk reduction of 30%. Comparable risks predicted using FHS-derived CHD risk equations are 0.116 for the placebo group and 0.088 for the intervention group. Consequent relative risks and risk reductions for the intervention relative to placebo are 0.757 and 24%, respectively. Using both model and trial estimates of CHD incidence in an economic evaluation of cholesterol-modifying pharmacotherapy, incremental costs per life year gained are 41,707 Pounds using WOSCOPS data and 36,480 Pounds using FHS-derived CHD risk equations.

Anticholesteremic Agents↗

PubMedDate not supplied

Assessment of the antitussive efficacy of codeine using cough sound pressure levels as a means of measuring cough.

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Adolescent↗

PubMedDate not supplied

Locomotion, respiratory physiology, and energetics of amphibious and terrestrial crabs.

The transition from breathing air to breathing water requires physiological and morphological adaptations. The study of crustaceans in transitional habitats provides important information as to the nature of these adaptations. This article addresses the physiology of air breathing in amphibious and terrestrial crabs and their relative locomotor abilities. Potamonautes warreni is an apparently amphibious freshwater crab from southern Africa, Cardisoma hirtipes is an air-breathing gecarcinid crab with some dependency on freshwater, and Gecarcoidea natalis is an obligate air-breathing gecarcinid endemic to Christmas Island in the Indian Ocean. All three species have well-developed lungs but retain gills and show seasonally different activity patterns that, in the gercarcinids, especially G. natalis, include long-distance breeding migrations. The three species were better at breathing air than water, but P. warreni was the best at breathing water. Cardisoma hirtipes is essentially an obligate air breather and appears to experience facultative hypometabolism during immersion. Cardisoma hirtipes has a haemocyanin with a high affinity for O(2) that facilitates loading from air but makes 30% of the Hc bound O(2) inaccessible. The gecarcinids but not P. warreni show increased diffusion limitation for O(2) over the lung during exercise. Gecarcoidea natalis outperforms C. hirtipes by virtue of a unique haemolymph shunt from the lung into the gills. Paradoxically, it is modifications of the gills for aerial O(2) uptake in G. natalis that allow for relatively greater haemolymph oxygenation. Despite showing decreased arterial-venous DeltaPo(2), P. warreni increased the arterial-venous Delta[O(2)] with no recourse to anaerobiosis during 5 min exercise. In the short term, P. warreni is more adept at walking than C. hirtipes. The breeding migrations of C. hirtipes and G. natalis were completely aerobic, but G. natalis walk farther and probably faster. Seasonal changes in underlying metabolism of G. natalis are strongly implied, including variations in hyperglycaemic hormone, variable basal metabolic rates, and a diel alkalosis present only in migrating crabs. The persistent dependence on water for reproduction is a determining factor in the biology of air-breathing crabs. The annual migrations include costs other than locomotion, for example, burrow construction and intermale competition. Estimates of costs that consider walking alone will underestimate the metabolic and stored fuel requirements for successful reproduction.

Animals↗

PubMedDate not supplied

Respiratory, acid-base, and metabolic responses of the Christmas Island blue crab, Cardisoma hirtipes (Dana), during simulated environmental conditions.

The dependency of the Christmas Island blue crab, Cardisoma hirtipes, on fresh water for respiratory gas exchange and transport was investigated in laboratory simulations. The gas exchange rates of air-breathing C. hirtipes were similar to those of other land crabs but decreased to 20% in submerged crabs. Crabs with access to air maintained arterial and pulmonary O2 content (CO2) and partial pressure (PO2), while in submerged crabs the PO2 and CO2 rapidly decreased (by 50%). There was no anaerobiosis, but haemolymph glucose concentration and cardiac output decreased when crabs were submersed, which suggests a hypometabolic state. Submersion induced a metabolic rather than a respiratory alkalosis, and since respiratory gas exchange was low, CO2 excretion to water was unimportant. Cardisoma hirtipes haemocyanin (Hc) has high O2 affinity but low pH sensitivity, which facilitates O2 uptake from hypoxic environments. The high Hc-O2 affinity supports O2 loading but may prevent access to a venous O2 reserve. Calcium, magnesium, and urate, but not L-lactate, were effectors of Hc-O2 affinity. In submerged crabs increased circulating urate maintained haemolymph O2 content. The CO2 capacitance and nonbicarbonate buffering of the haemolymph were relatively low. A significant Haldane effect seemed important for CO2 excretion but would require CO2 and O2 exchange to occur at the same organ (gills or lungs). Submersion interferes with respiration and is not needed for haemolymph acid-base balance; thus; C. hirtipes is an air-breathing crab.

Acid-Base Equilibrium↗

PubMedDate not supplied

Respiratory, blood-gas transport, and acid-base response of Leptograpsus variegatus to long-term immersion and hyposaline exposure.

The respiratory and acid-base responses of the supratidal crab Leptograpsus variegatus to immersion in either 100% or 50% seawater were measured over a 3-wk period. Leptograpsus maintained haemolymph PO2 and CO2 during immersion, owing partly to elevated cardiac output and without recourse to hyperventilation. Both haemolymph PCO2 and CCO2 were reduced following 3 wk of immersion, and L-lactate remained low, but nonetheless Leptograpsus exhibited a marked metabolic acidosis. Specific responses to 50% seawater exposure were observed in Leptograpsus when compared with control crabs immersed in 100% seawater. Improved O2 delivery concomitant with elevated perfusion and ventilation maintained haemolymph oxygenation. In hyposaline-exposed Leptograpsus, both PCO2 and CCO2 were reduced after 24 h, while pH was elevated after 15 min and remained so during the 3-wk immersion. The marked acidosis exhibited in Leptograpsus exposed to 100% seawater was partially reduced in those in 50% seawater, presumably because of net acid excretion associated with elevated Na+ uptake. Immersion of Leptograpsus reduced Hc-O2 affinity to a greater extent in hyposaline-immersed individuals, while the cooperativity of O2 binding by Leptograpsus Hc decreased at low pH in both salinities. When immersed, the respiratory status of Leptograpsus resembles that of water-breathing crabs. Exposure to 50% seawater causes a twofold increase in energetic cost but does not perturb the immersed condition. The metabolic acidosis induced by chronic immersion is partially compensated at the lower salinity. Leptograpsus thus has the ability to take advantage of habitats ranging from supratidal through brackish to fully marine.

Acid-Base Equilibrium↗

PubMedDate not supplied

Self-inflicted patient burns: suicide versus mutilation.

Though suicide by burning is well-described, little information is available regarding patients who mutilate themselves by burning without suicidal intent. We reviewed 31 patients admitted from 1980 to 1991 with self-inflicted burns to describe differences between self-mutilation and attempted suicide (AS). In 16 patients who had mutilated themselves, mean burn size was 1.6% TBSA (range 0.3% to 9.0% TBSA) compared with 35.4% TBSA in the 15 patients who had attempted suicide (range 11.5% to 90% TBSA; p < 0.0001). Twelve of 15 patients who had attempted suicide used flammable liquids for self-immolation, whereas patients who had mutilated themselves often used techniques that they could control, including scalding, chemicals, and contact injuries. Most patients in both groups and previous histories of psychiatric disorders. Self-mutilators had a high incidence of personality disorders (56%), whereas the AS group more frequently suffered from depression (47%). Nine (56%) patients who had mutilated themselves had previous self-inflicted burns, compared with only one patient in the AS group. Mean lengths of stay, number of surgeries, and hospital and physician charges were higher for the AS group. Case examples of both types of injuries are presented. Burn care professionals should be familiar with syndrome of self-mutilation by burning. Patients often present with puzzling injuries and require psychiatric treatment in addition to burn care.

Adult↗

PubMedDate not supplied

Adopt A School.

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Career Choice↗

PubMedDate not supplied

Patients with HIV dying in Edinburgh: an audit of preference and place of death.

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Adult↗