Felix Largiader

Acute hypercalcemia induces acinar cell necrosis and intraductal protein precipitates in the pancreas of cats and guinea pigs.

The effect of local and systemic calcium administration was tested on the pancreas of cat and guinea pig. After 3 h of local calcium infusion (0.6 mmol/kg x h) via the splenic artery of the cat hemorrhagic pancreatitis could be shown. Control animals treated with potassium (1.1 mmol/kg x h) or 0.9% NaCl alone showed no morphological change in the pancreas. Intravenous administration of calcium (0.6 mmol/kg x h) led to a 1.8-fold increase in serum ionized calcium levels in the cat and a 1.6-fold increase in levels in the guinea pig. The cat showed necrosis of acinar and ductal cells throughout the gland at 12 h. In the guinea pig, acinar cell vacuolisation and cell necrosis started at 3 h, and at 9 h degeneration of entire acini, hydropic swelling and degeneration of ductal cells, and perivascular leukocytic infiltration was present. In both species, a significant increase in the number of intraductal precipitates and a significant increase in urinary amylase output was present in calcium treated animals. The findings suggest that hypercalcemia has a deleterious effect on the pancreas that causes acinar and ductal cell necrosis and eventually pancreatitis.

Individual in vitro organ susceptibility to hyperbaric oxygen.

Summary o 1. Preservation of whole organs (kidney, heart, small bowel, and lung) has been investigated in relation to individual in vitro susceptibility to hyperbarie oxygen. 2. The lung, in sharp contrast to other organs, does not tolerate pressures above 3.0 OHP. 3. The critical oxygen tension required for successful preservation appears related to duration, intensity, and core depth of the individual organ.

The duration of achlorhydria attending freezing of the isolated canine gastric pouch

Summary o 1. Forty-two dogs underwent gastric pouch freezing, and gastric tissue temperature studies were done concomitantly in 27 dogs. In most cases, uniform temperature depression was observed using thermocouples at different locations on the balloon surface and within the same submucosal tissue plane of the pouch. The average balloon surface temperature was 3.4° colder than the mean submucosal temperature. 2. The uniformity of temperatures is due in part to a high heat transfer coefficient or efficiency of the small round balloon used. The efficiency of the larger stomach-shaped balloon used in freezing the intact canine stomach is lower. 3. In Group H B a tissue temperature of −2° to 4° C. maintained for 40 minutes produced an average achlorhydric period of 16.2 weeks (3 of 8 dogs are still achlorhydric at 16, 28 and 30 weeks). Doubling the duration of freezing from 20 to 40 minutes at these temperatures exerted a 2000 per cent increase in duration of the achlorhydria. These freezing conditions appear to be a safe limit for the intact stomach. Methods to improve the efficiency of freezing of the intact stomach are being studied.

Protection afforded by low molecular weight dextran against the post-freeze gastric ulcer in the dog

Summary An experience with 65 dogs subjected to gastric freezing for 30 minutes with inflow temperatures of −18.6°, −20° or −29.4° C. (Groups I, II or III) indicated a definite incidence of post-freeze gastric ulcer for each group. Superficial erosions also occurred, but most did not seem to bleed or cause serious concern. The incidence and size of post-freezing gastric ulceration in Groups I and II was influenced favorably by the prior intravenous infusion of low molecular weight dextran at doses of 2 gm./kg. body weight. Mortality from post-freeze ulcers was lowered from 7 deaths (30.4 per cent) in control Groups I and II, to 1 death (4.5 per cent) in the corresponding dextran groups. The limit of effectiveness of this agent was approached at inflows of −29° C. in Group III in which 5 of 6 dogs developed post-freeze ulcers, two of them dying from perforation. The secretory depression attending freezing of Heidenhain pouches was not abrogated by systemic use of low molecular weight dextran. The clinical use of low molecular weight dextran in man during gastric freezing may offer promise of decreasing the 2 per cent observed incidence of the post-freeze gastric ulcer.

Experimentelle Coronarflowumkehr im Descendensgebiet des Hundeherzens

SummaryThe influence of retrograde perfusion of the vena cordis magna on the sequelae of ligaturing the anterior descendens coronary artery was investigated in acute canine experiments. The results prove that a real inversion of the coronary circulation with an effective tissue perfusion can be obtained. In some cases (3 out of 23) the inversion of the flow prevents ventricular fibrillation. Besides these favorable results a few disadvantageous effects have been noted. The high arterial pressure in the venous system may cause extravasations. By the way of venous collaterals more than 80 percent of the blood may be shunted away from the area to be perfused. The tissue perfusion may be irregular. Further studies with experiments designed for long term survival are therefore necessary.ZusammenfassungBei Hunden wurde der Einfluß der retrograden Perfusion des Descendens anterior-Gebietes auf die Folgen der Ramus descendens-Ligatur untersucht. Aus den Akutversuchen geht hervor, daß im Coronarsystem eine Flowumkehr zu verwirklichen ist und daß eine echte Gewebedurchblutung stattfindet. Im günstigsten Fall (3 von 23 Tieren) kann die Flowumkehr ein Kammerflimmern verhindern. Diese Vorteile sind aber mit nachteiligen Begleiterscheinungen verbunden. Die Coronarvenen halten dem hohen arteriellen Druck nicht immer stand, weswegen Gewebeblutungen entstehen können; die venösen Kollateralen leiten mehr als 80% des in die Venen einströmenden Blutes vom Descendensgebiet ab, und die Gewebedurchströmung ist ungleichmäßig, weswegen Zirkulationsstörungen und Infarktzeichen im EKG auftreten. Das Problem der Coronarflowumkehr sollte daher mit weiteren, auf Langzeitüberleben ausgerichteten Versuchen abgeklärt werden.