Collagenase was injected into the ears of rabbits and the cheek-pouches of hamsters. The acute and long-term microvascular effects were studied by vital microscopy and microangiography. The enzyme was injected at three different concentrations: 120 units/ml, 600 units/ml and 3,000 units/ml. The medium (600 units/ml) and high (3,000 units/ml) concentrations induced effects on the microcirculation such as blood flow impairment and microbleedings. The magnitude of these effects was related to the concentration of the enzyme. Generally, these microvascular effects were of low magnitude as compared with other substances tested using the same experimental models.

In an attempt to determine the best provocative test for the diagnosis of gastrinoma, ten normal subjects, 13 patients with known gastrinoma, and one patient with presumed gastrinoma were administered four regimens: (1) rapid calcium infusion (2 mg Ca++/kg/min), (2) secretin (2 clinical units (CU)/kg/bolus), (3) long calcium infusion (12 mg Ca++/kg/3 h) and (4) a combination test consisting of a rapid calcium infusion followed immediately by secretin. Blood was drawn for serum gastrin levels before and following infusion of the test agents. The administration of rapid calcium followed by secretin provoked the greatest increases in serum gastrin above basal levels in both normals (29%) and patients (362%). Peak gastrin levels in patients were similar following the long calcium infusion (341%) but were less following the rapid calcium infusion alone (124%) and secretin alone (207%). There were no false-positive or false-negative tests with the calcium plus secretin when the criterion for diagnosis was either a 50% increase or a 200 pg/ml increase above the basal gastrin level. The distinct advantages (short test period, low patient morbidity, and relatively great potency) of the calcium plus secretin test make it an attractive alternative to other previously described provocative tests for the diagnosis of gastrinoma.

No abstract

In man, using a skin tube chamber technique, microvascular reactions during and after complete experimental ischemia was studied by intravital microscopy. During 1 and 2 hour ischemia the trapped blood cells did not adhere to each other or to the vascular walls except for RBCs which formed rouleaux. Reflow after 1 and 2 hour ischemia was rapid with a hyperemic reaction and a transient increase in WBC stickiness. Thus, a mild and reversible inflammatory reaction was provoked by the short ischemic insult. During 6 hour ischemia most of the blood cells maintained their integrity. However, in a few vessels the RCSs formed homogeneous masses indicating hemolysis of some of the RBCs. There was also marked diapedesis of RBCs and increased WBC stickiness, but the platelets did not react to form thrombi. After the 6 hour ischemia reflow occurred in all vessels and the homogeneous masses seemed to cause only a temporary hindrance to reflow. The final outcome of the 6 hour ischemic insult was uncertain since in one of the two experiments there was a complete circulatory standstill 24 hours after the ischemia while in the other there was an almost normal blood flow.

Dequalinium chloride is a quaternary ammonium compound used for the treatment of infected skin and mucosal lesions. Its influence on the healing of incisional wounds in rat skin has been studied by a tensiometric technique. The breaking load was significantly lower in wounds that had been exposed to an aqueous solution of dequalinium chloride than those exposed to distilled water. The concentrations of dequalinium chloride were well below those used in clinical practice. The results obtained from incisional wounds are probably valid also for open wounds. The results are correlated with the microcirculatory disturbances demonstrated in previous studies. This suggests that the use of dequalinium chloride in treating human wounds should be re-evaluated.