The variations between different lots of activated partial thromboplastin time (APTT) produced by three major North American suppliers were evaluated over the past eight years. The authors found significant variations between the heparin sensitivity of the APTT reagents produced under the same name by the same supplier. The variations were so much that, using the recommended APTT ratio or prolongation of APTT for monitoring heparin therapy, one would have achieved significantly different intensity of heparinization from year to year.

No abstract

The epitheloid cells forming the granulomata of Crohn's disease show striking vacuolation from the coalescing of pinocytotic vesicles with double membrane-bound bodies and their subsequent fusion with lysosomal dense bodies. The fine detail of the granulomata in each individual is uniform but varies from case to case in such a way as to suggest an episodic stimulation of pinocytosis and vacuole formation. The production of such granulomata with these cyclical appearances is consistent with an intermittent stimulus by exogenous antigen or antigen antibody complexes arriving in the diet.