Scales for the measurement of attitudes toward blood donation

Attitudes toward blood donation are frequently assumed to vary along a single dimension from unfavorable to favorable. In contrast, theories of attitude structure specify three distinct attitude components: affect, cognition, and behavior. This article describes the development of three new scales for the measurement of affective, cognitive, and behavioral components of attitudes toward blood donation. The scales were developed using the method of equal-appearing intervals and were administered to both donors of blood and nondonors. Correlations among the scales were relatively small and supported the three-component distinction. Affect was more strongly correlated with the number of prior donations than was cognition, which suggested an important role for emotional factors in blood donation. Scores on all three scales showed the attitudes of blood donors to be more favorable than those of nondonors.     

Amino acid profiles during development of the fetal rat

Umbilical blood venous-arterial differences for amino acids across the rat fetus show uptake of disproportionately large amounts of glutamine, alanine and lysine relative to their contribution to total body protein. Free amino acid concentrations in fetal liver tend to increase during development, but show a rapid adjustment to near-adult values within 24 h after birth.     

A reliable and readily available method of measuring limb blood flow in intermittent claudication

To evaluate isotope limb blood flow measurement in intermittent claudication we have assessed 58 non-diabetic patients comparing our new method with treadmill testing and Doppler assessment. Limb blood flow was applicable to all 58 patients; 25 patients were unable to walk on a treadmill and of the 33 who could 12 failed to walk for one minute, making a standard one minute exercise test inappropriate. In those patients who could perform exercise tests there was a significant correlation between maximum walking distance and limb blood flow (r = 0.35, P = 0.02). Resting, post-exercise and post-hyperaemic ankle-brachial systolic pressure indices bore no relationship to the maximum walking distance. Isotope limb blood flow measurement is reproducible (r = 0.97), can be applied to those patients who cannot walk on a treadmill and provides information about both legs. It correlated significantly with all the other tests and can be recommended for the minimally invasive assessment of intermittent claudication.     

Peroxidative aggregation of myelin membrane proteins

The exposure of CNS myelin to reactive oxygen species (ROS) generated by a Cu²⁺–H₂O₂ system results in the aggregation of membrane proteins. Integral and peripheral membrane proteins are equally vulnerable and the denaturation is not mediated by the SH groups. The aggregated proteins retain their original antigenicity as determined by immunoblot technique. The aggregation of proteins is not limited to myelin and can be elicited in the preparation of other cerebral membranes. The effect of ROS on membrane proteins can also be demonstrated in cerebral slices incubated in the presence of the ROS-generating system. Furthermore, the peroxidation inactivates membrane-bound enzymes as exemplified by myelin cyclic nucleotide phosphatase (CNP). Competitive inhibition studies with various scavengers and quenchers of ROS implicate singlet oxygen as a major mediator in the Cu²⁺–H₂O₂ oxidizing system responsible for the peroxidative aggregation of membrane proteins.     

Procoagulant activity in normal human urine associated with subcellular particles

Procoagulant activity (PCA) in normal human urine was found to be sedimented by centrifugation at X 100,000g. Therefore, studies were done to identify the structures associated with the procoagulant activity. Transmission electron microscopy of the X 100,000g pellet revealed numerous membrane-bound vesicles as well as fibrous material. Filtration of normal urine through a 0.2-micron filter removed more than 90% of the procoagulant activity. Scanning electron microscopy of the filter surface revealed 0.1 to 1.1 micron particles and fibrous material. By centrifugation at pH 3 and 5 the fibrous material and particles were separated. The procoagulant activity remained with the particles in each case. The fibrous material was shown to be Tamm-Horsfall protein by SDS-PAGE and Western blotting using anti-Tamm-Horsfall protein serum. Purified Tamm-Horsfall protein itself was not procoagulant. Therefore, PCA in normal human urine is associated with particles 0.1 to 1.1 micron in diameter which appear to be lipid membranes in various arrangements.     

A qualitative test of the balloon model for BOLD-based MR signal changes at 3T.

The aim of this study was to adapt the balloon model for BOLD-based MR signal changes to a magnetic field strength of 3T and to examine its validity. The simultaneous measurement of BOLD and diffusion-weighted BOLD responses was performed. The amplitude of the BOLD peak was found to be similar for all subjects when a short visual stimulus of 6 sec was used. The rise-time to the BOLD peak and the shape and depth of the poststimulus undershoot varied significantly. A fit of the experimental BOLD responses was found to be possible by use of parameters within a reasonable physiological range. The relations between these parameters and their influence on the modeled BOLD responses is discussed. A prediction of the balloon model is the occurrence of a BOLD overshoot, i.e., a lag between the changes of the blood volume and the blood flow after the start of the stimulation. Experimental evidence for the existence of a BOLD overshoot is presented.     

Hepatic perfusion index and the evolution of liver metastases

A total of 150 patients with primary carcinoma of the gastrointestinal tract had first-pass technetium colloid scintigraphy to estimate the hepatic perfusion index (HPI). Postoperative follow-up over 2-4 years shows that the HPI remains a sensitive method of detecting hepatic metastases, even in patients whose liver appeared normal at laparotomy. HPI was elevated in 94% of patients with liver metastases found at laparotomy; 87% of patients with occult metastases which became overt within 3 years of surgery had elevated HPI; and 91% of all patients who have to date developed hepatic metastases had elevated HPI at presentation. Of all patients with elevated HPI, 82% had metastases which were either apparent at surgery or became detectable by other means within 3 years.