A Simple Method for the Assay of Factor VIII

A simple method for the assay of factor VIII activity, based on the thromboplastin generation test of Biggs and Douglas, has been described.

Bovine serum is used as a source of factor V and serum factors, and plasmafrom a hemophiliac is not required. The concentration of factor VIII of thetest plasma is compared to that of a standard normal human plasma. Theresults obtained with the method have been fairly reproducible.

     

IMMUNOBIOLOGY OF CHILDHOOD DISEASES

A large part of clinical paediatrics deals with infectious disease, inflammatory conditions, allergy, auto-immune disease and cancer. The immune system plays a critical role in these diseases and in addition presents a perplexing number of conditions arising from defects in the immune system itself. This review seeks to highlight immune mechanisms in selected diseases of children and to explore the clinical value of these mechanisms in terms of diagnostic or therapeutic application. Some of the principles and mechanisms involved in immune defence have been previously considered (Jose, 1973).     

Some Aspects of Human and Canine Macroscopic Pancreas Innervation

Both vagus nerves and the celiae ganglion complex are the main source of the pancreatic gland innervation. In both man and dog there is a distinct difference in the number of fibers ending in the different segments of the gland. In the former, the macroscopic innervation is primarily concentrated in the pancreas head and isthmus. In the latter most of the nerves enter through the upper part of the right limb (uncinate process). Both vagus nerves send direct fibers to the gland but in most of the nerves, that course in general along the different branches of the celiac and mesenteric arteries, the parasympathetic and adrenergic fibers are intermingled. The anterior hepatic plexus, continued down by the gastroduodenal, completes a nervous circle, at the lower edge of the pancreas, with the branches arising from the splenic plexus. In human pancreas most of the nerves, with the exception of the branches given off by the gastroduodenal network, enter the gland by its periphery, either through its superior or inferior border. The gastroduodenal plexus is the pathway for the duodenopancreatic and the duodenogastric are reflexes and for the "pancreatic type" of pain triggered by some posterior penetrating duodenal ulcers.     

Right Atrial-ventricular Dissociation and Entrainment while Pacing from High Right Atrium and Coronary Sinus during Circus Movement Tachycardias

Thirteen patients with circus movement tachycardias (CMT) were studied. Twelve had left-sided, and one, right-sided, accessory pathways. Entrainment was possible during overdrive high right atrial stimulation in 13/13 patients, and during coronary sinus pacing in 10/12 patients. The minimal pacing rates required for this to occur were 10 to 31 beats/min faster than those of the tachycardias. Short episodes of right atrial-ventricular dissociation occurred while pacing from the high right atrium (6/13 patients), but not from the coronary sinus (0/13 patients). It is possible to explain this phenomenon by postulating the existence of two distinct atrioventricular (AV) nodal inputs (one for right-sided and the other for left-sided impulses); it could also have been an expression of the close distance existing between the AV node and the coronary sinus. Entrainment, by defining a range of pacing rates followed by resumption of the tachycardia upon the cessation of stimulation, indicated that faster rates were needed for the CMT to be interrupted. However, regardless of the pacing rate and pacing site, tachycardia termination occurred when an anterograde impulse was blocked at the AV node. The information obtained from this study suggests that some patients with drug-resistant CMT may benefit from pacing modes capable of terminating the arrhythmia "through entrainment" at the slowest atrial rate at which this is possible.