Rat mesenteric resistance vessels (RV) were characterized with respect to concentration of individual alpha-subunit isoforms of Na,K-ATPase.Total vessel homogenates were used to avoid any loss or subfractionation of membranes. They were applied to sodium dodecyl sulphate gels and, for calibration, in parallel lanes were run purified rat Na,K-ATPase preparations with known isoform distribution and content. The capacity per mg protein for Na+-dependent 32P-phosphorylation of Na,K-ATPase isolated from rat kidney was used for alpha1 calibration and that for high-affinity (3H)ouabain binding of Na,K-ATPase isolated from rat brain was used for (alpha2 + alpha3) calibration. Western blots containing homogenate proteins and reference enzyme were incubated with isoform-specific antibodies and radiolabelled secondary antibodies. The signals from adjacent alpha spots were used for qualitative and quantitative characterization of rat vessels.A concentration of 100.7 +/- 14.4 pmol (n = 11) per g wet weight of the alpha1-isoform containing Na,K-ATPase was found in RV from 12-14-week rats. A much lower and more unreliable content of alpha2- and alpha3-isoforms was found. These ouabain-sensitive isoforms seem to represent a maximum of 5-10% each compared with the ouabain-insensitive rat alpha1-isoform.The isoform pattern in RV, in which the isoform with high/intermediate Na+-affinity is the absolutely dominating one representing nearly all sodium pumps in this tissue, is very different from that seen in rat skeletal muscles. Due to the high content of the ouabain-insensitive alpha1-isoform in rat RV this species would seem a less relevant model in studies addressing a role of cardiac glycosides and putative endogenous ouabain-like factors in hypertension.
The purpose of this study was to quantify the set-up errors of patient positioning during IGRT and to correlate set-up errors to patient-specific factors such as weight, height, BMI, and weight loss.Thirty four consecutively treated head-and-neck cancer patients (H&N) and 20 lung cancer patients were investigated. Patients were positioned using customized immobilization devices consisting of vacuum cushions and thermoplastic shells. Treatment was given on an Elekta Synergy accelerator. Cone-beam acquisitions were obtained according to a standardized Action Limit protocol and compared to pre-treatment CT images. The average 3D deviation from three initial cone beam scans was compared to deviations at the 10th and 20th treatment session and correlated by linear regression analysis to height, weight, and BMI, and in H&N to weight loss as expressed by the relative weight change over time.The SD of the translational and rotational random set-up errors during the first three sessions for H&N were 0.9 mm (Left-Right), 1.1mm (Anterior-Posterior), 0.7 mm (Cranio-Caudal) and 0.7 degrees (LR-axis), 0.5 degrees (AP-axis), and 0.7 degrees (CC-axis). The equivalent data for lung cancer patients were 1.1 mm (LR), 1.1mm (AP), 1.5 mm (CC) and 0.5 degrees (LR-axis), 0.6 degrees (AP-axis), and 0.4 degrees (CC-axis). The median BMI for H&N and lung was 25.8 (17.6-39.7) and 23.7 (17.4-38.8), respectively. The median weekly weight change for H&N was -0.3% (-2.0 to 1.1%). With H&N and lung cancer analyzed separately, no statistically significant correlation was observed between set-up errors and height, weight, BMI, or weight change during treatment, irrespectively whether the 3D deviations from the initial three cone beam scans or scans from the 10th or 20th treatment sessions were used.This IGRT study did not support the hypothesis that set-up errors during radiotherapy are correlated to patient height, weight, BMI, or weight loss.
The Mapleson A, B, C and D circuits can be changed into non‐polluting circuits by employing continuous gas evacuation directly from the circuit, via an ejector flowmeter (J ørgensen 1974); Mapleson A and C circuits with this modification have been described previously as the Hafnia A and C circuits (C hristensen 1976, T homsen & J ørgensen 1976). If evacuation from a closed reservoir is employed, total removal of the expired and surplus gases from the operating theatre is obtained (J ørgensen & T homsen 1976). There will be resistance to expiration in all the circuits with a relief valve for the discharge of surplus gas. If surplus gas is continuously removed directlyfrom the anaesthetic circuit, the patient breathes in an air compartment at ambient pressure, as long as the removal rate equals the inflow of fresh gas. The relief valve is only included in the circuit to ensure that high pressures do not develop. As in any other circuit, the relief valve remains open except during controlled ventilation. A dumping valve may also be included as a safeguard against low pressures (J ørgensen & T homsen 1976). The flow requirements of the Hafnia B and D circuits and the corresponding Mapleson circuits have been studied in conscious, spontaneously breathing subjects, and the results are discussed in relation to the flow requirements of other semi‐closed systems.
