C1-Cx revisited: intramolecular synergism in a cellulase.

Endoglucanase A (CenA) from the bacterium Cellulomonas fimi is composed of a catalytic domain and a nonhydrolytic cellulose-binding domain that can function independently. The individual domains interact synergistically in the disruption and hydrolysis of cellulose fibers. This intramolecular synergism is distinct from the well-known intermolecular synergism between individual cellulases. The catalytic domain corresponds to the hydrolytic Cx system and the cellulose-binding domain corresponds to the nonhydrolytic C1 system postulated by Reese et al. [Reese, E. T., Sui, R. G. H. & Levinson, H. S. (1950) J. Bacteriol. 59, 485-497] to be required for the hydrolysis of cellulose.     

Effect on blood volume of maintaining a high central venous pressure after major aortic valve surgery

Fluck, D. C., Lopez Bescos, L., and Gilkes, R. (1973).Thorax,28, 762-767. Effect on blood volume of maintaining a high central venous pressure after major aortic valve surgery. Serial blood volume measurements were made in 15 patients undergoing major aortic valve surgery requiring cardiopulmonary bypass. In all patients the plasma volume was measured by iodine-125 (¹²⁵I) labelled albumin and in 10 the red cell mass was measured by chromium-51 (⁵¹Cr) labelled red cells. Close correlation was found between the blood volume derived from the plasma volume and central venous haematocrits and the blood volume derived by addition of the plasma volume and red cell mass. Postoperatively blood was given to maintain the right atrial pressure at between 10 and 15 cm H₂O. Before operation the red cell mass, and plasma and blood volumes related to body weight were within the normal range. In the postoperative phase the first measurement two hours after the end of the operation showed a significant decrease in mean blood volume, red cell mass, and plasma volume as compared with the preoperative level. By the second postoperative measurement six hours after the end of operation the mean blood volume had risen to the preoperative level. Subsequently, over postoperative days 1 to 6 the mean blood volume remained steady, although the red cell mass tended to fall. After blood transfusion had ceased the red cell mass usually showed a progressive fall. It was considered that although there was little relationship between the right atrial pressure and the blood volume there was little or no clinical value in performing serial postoperative measurements of blood volume in addition to venous pressure monitoring in these patients.     

Relationship between the serum autoantibody titers and the clinical activity of pemphigus vulgaris

With human tonsillar epithelium as a substrate for the indirect immunofluorescence assay, a statistically significant relationship was demonstrated between the clinical activity of the disease and the autoantibody titers in seventy-eight serum samples obtained from patients with pemphigus vulgaris. High pemphigus antibody titers were associated with severe ulceration, intermediate titers with moderate lesions, and low titers with mild pemphigus. However, the sequential studies revealed that this relationship was not always consistent throughout the course of the disease, and in three out of fourteen patients the correlation was either poor or negative. These results indicate that serial pemphigus antibody titers may not be consistent enough to be used reliably as the sole guide for monitoring disease activity.