Marsh (1952) first showed that whereas the apparent rate of hydrolysis of adenosine triphosphate (ATP) by homogenates of fresh rabbit muscle in an isotonic solution of potassium chloride was comparatively low, after centrifuging and removal of the soluble protein extract a considerable increase in the rate of production of inorganic phosphate by the residue occurred when it was resuspended in fresh potassium chloride solution. On the basis of these findings Marsh concluded that there was present in muscle a factor which inhibited adenosine triphosphatase (ATPase) activity, and he further demonstrated that in the presence of this factor ATP caused an increase in the volume of the cell fragments in the suspension. Bendall (1953 a) extended Marsh's findings and was able to bring about the relaxation of glycerated fibres by the application of ATP in the presence of preparations of the Marsh factor. He also confirmed the inhibitory action of the factor on the ATPase activity of homogenized glycerated fibres. Further investigations by Hasselbach & Weber (1953) on the ATPase activity of these preparations showed that at higher concentrations ATP was inhibitory, and in the presence of the Marsh factor the level at which ATP became inhibitory was considerably reduced.It is clear from the investigations mentioned above and those of Bozler & Prince (1953) that, in general, relaxation in muscle models is associated with a low rate of ATP hydrolysis. Magnesium appears to be of special importance in the contraction-relaxation cycle, yet the precise role of this metal is far from clear. Although magnesium is essential for relaxation (Bendall, 1953a), reagents which form complexes with magnesium, namely ethylenediaminetetraacetate (EDTA) (Bozler, 1954;Watanabe, 1955) and inorganic pyrophosphate (Weber, 1951;Bozler, 1951; Bendall, 1953b) also bring about relaxation of glycerated fibres. Bendall (1953b) has commented on the similarity between the relaxing action of the Marsh factor and that of inorganic pyrophosphate, and it is conceivable that one of the properties possessed in common by these substances is the ability to complex with magnesium.Glycerated fibres consist mainly of myofibrils, but studies on the ATPase activity ofthese fibres are not entirely satisfactory, as preparations may be contaminated with sarcoplasmic granules and nuclei which also possess ATPase activity, and with varying amounts of sarcoplasm. Furthermore, precise analysis of such experiments in terms of substrate and activator concentrations at any point in the fibre is difficult because concentration gradients will be produced by the diffusion of ATP to the myofibrils from the outside of the fibre. To throw more light on the enzymic behaviour of the myofibril a study has been made of the ATPase activity of isolated myofibrils, with particular reference to those conditions that bring about the low level of activity which is characteristic of relaxation. It has been shown that at a low ionic strength the marked inhibition of ATPase activity by ATP is de...

Objectives To determine whether preoperative dexamethasone reduces postoperative vomiting in patients undergoing elective bowel surgery and whether it is associated with other measurable benefits during recovery from surgery, including quicker return to oral diet and reduced length of stay. Design Pragmatic two arm parallel group randomised trial with blinded postoperative care and outcome assessment. Setting 45 UK hospitals. Participants 1350 patients aged 18 or over undergoing elective open or laparoscopic bowel surgery for malignant or benign pathology. Interventions Addition of a single dose of 8 mg intravenous dexamethasone at induction of anaesthesia compared with standard care. Main outcome measures Primary outcome: reported vomiting within 24 hours reported by patient or clinician. Secondary outcomes: vomiting with 72 and 120 hours reported by patient or clinician; use of antiemetics and postoperative nausea and vomiting at 24, 72, and 120 hours rated by patient; fatigue and quality of life at 120 hours or discharge and at 30 days; time to return to fluid and food intake; length of hospital stay; adverse events. Results 1350 participants were recruited and randomly allocated to additional dexamethasone (n=674) or standard care (n=676) at induction of anaesthesia. Vomiting within 24 hours of surgery occurred in 172 (25.5%) participants in the dexamethasone arm and 223 (33.0%) allocated standard care (number needed to treat (NNT) 13, 95% confidence interval 5 to 22; P=0.003). Additional postoperative antiemetics were given (on demand) to 265 (39.3%) participants allocated dexamethasone and 351 (51.9%) allocated standard care (NNT 8, 5 to 11; P<0.001). Reduction in on demand antiemetics remained up to 72 hours. There was no increase in complications. Conclusions Addition of a single dose of 8 mg intravenous dexamethasone at induction of anaesthesia significantly reduces both the incidence of postoperative nausea and vomiting at 24 hours and the need for rescue antiemetics for up to 72 hours in patients undergoing large and small bowel surgery, with no increase in adverse events. Trial registration EudraCT (2010-022894-32) and ISRCTN (ISRCTN21973627).

No abstract

No abstract

The effects of age and sex have been studied on the proximate composition and inorganic constituents in breast, thigh, drumstick and skin from a commercial British broiler strain (Ross 1). Protein content generally increased with age in all muscles and decreased in skin. Protein content in skin of males was always higher than that in females. Moisture content in all muscles decreased with age. In the skin, moisture decreased with age considerably more in females than in males. Fat content increased with age in all tissues, while ash content of breast, thigh and skin decreased with age. Phosphorus, chloride, magnesium and potassium all decreased with age in all the tissues. Thigh and skin calcium content were affected by age, as was the sodium content of drumstick and skin. The sex effect on the inorganic constituents was variable.