Ex vivo versus in situ resection of segmental liver grafts in pigs--a comparison in immediate and four-hour-stored grafts

This study compared the function of reduced grafts prepared in situ or ex vivo and transplanted immediately or after 4 hr of cold storage. Measurements of acid/base balance, plasma electrolytes, albumin, and urea showed no differences between groups. There was no difference between the increase and decline of plasma AST in recipients of grafts transplanted immediately after either ex vivo or in situ reduction; the increase in plasma AST of recipients of stored grafts was up to 10-fold and persisted until the end of the study at 7 days, with some decline. Plasma fibrinogen decreased intraoperatively but levels were restored within 24 hr in all groups; plasma prothrombin and partial thromboplastin times were not significantly disturbed. The patterns of decline and return of tissue adenine nucleotides were similar in all groups. While the regenerative response measured by tissue thymidine kinase and mitotic figures was not different between the groups, comparison with results from a group of partially hepatectomized animals showed a 3-4-fold depression in response in reduced liver grafts. The contributions of the effects of ischemia, flushing, and preservation to the depressed regenerative response of reduced liver grafts need to be determined. The present studies suggest however, that with regard to functional assessment, results are not affected either by ex vivo or in situ reduction of the graft, or by cold storage for 4 hr.

Administration of sucralfate prolongs survival of animals with experimental peptic ulceration

Ligation of the pig bile duct (BDL) results in 100% incidence of pars esophageal ulceration within 48 hours of the procedure. Usually such ulceration is uniformly fatal unless a highly selective vagotomy is performed simultaneously with the BDL. The administration of sucralfate to pigs with BDL prolonged their survival for up to 7 days, with evidence of healing of the ulcer on macroscopic and histologic observations. An increase in cell proliferation in the squamous epithelium of the ulcerated area was also seen in this sucralfate group. These features were not seen in controls, pigs with BDL only, or pigs with BDL and with magaldrate (Riopone), colloidal bismuth subcitrate (DeNol), or carbenoxolone. Analysis by Sepharose 2B gel filtration showed that there was no significant difference in the amounts of polymeric mucin in any group, with a wide scatter of the data seen especially for pigs in the untreated BDL-only group. This study suggests that sucralfate may enhance healing in this experimental pig ulcer model via a mechanism independent of the stimulation of mucus secretion. We propose that coating the mucosa with sucralfate provides a temporary substitute barrier that creates a microenvironment conducive to wound repair by mucosal proliferation.

Transhepatic sampling during experimental porcine liver autotransplantation--its application to measurements of insulin, glucagon, and glucose

Controversy still exists in the published literature about the need for administration of intravenous glucose during liver transplantation. The ability of the grafted liver to metabolize insulin and glucagon and the appropriateness of secretion of these hormones are addressed in the present study. Two groups of pigs received unstored liver autografts, one with free infusion of 10% glucose and the other with limited infusion of 2.5% glucose solution, while attempting to maintain plasma glucose levels less than 200 mg/100 ml. In these animals, irrespective of moderate or major hyperglycemia, serum insulin levels were appropriate for blood glucose concentrations. However, in both groups, plasma glucagon levels rose three- to fourfold more than preoperative values and were inappropriate. Although facilities for measurement of blood flow were not available, application of the technique of transhepatic sampling has revealed that hepatic handling of insulin seems to be unimpaired after autograft with limited ischemia. Pancreatic secretion of glucagon, however, appeared to increase during the period immediately after revascularization. It is suggested that transhepatic sampling methods may be used in experimental transplantation to elucidate the effects of storage for prolonged periods.

Sucralfate in the prevention of porcine experimental peptic ulceration

Sucralfate is the first drug to be shown to prevent ulceration in bile duct-ligated pigs. Usually such ulceration is uniformly fatal. Seven pigs in each of four groups in this study received only saline, or sucralfate (1 g every six hours), famotidine (40 mg per day), or misoprostol (200 micrograms every six hours). A Foley catheter was placed into a gastrectomy after bile duct ligation. Similar groups of sham-operated pigs were also prepared. After 48 hours, all saline-, famotidine-, or misoprostol-treated pigs showed severe macroscopic ulceration, whereas only two of those treated with sucralfate showed minimal macroscopic ulceration. Until now, only highly selective vagotomy has reduced ulceration caused by bile duct ligation. The present results suggest that acid inhibition is not the only important factor in healing bile duct ligation-induced peptic ulceration.

The effect of hepatic devascularisation in the pig upon the energy charge and ketone ratio

This study describes the effects upon various functions of the porcine liver, especially the energy charge, after ligation of the hepatic artery or diversion of portal venous blood either with or without revascularisation by arterial or vena caval blood. Energy charge was significantly reduced for up to 2 days after arterial ligation but by 7 days was showing a return towards normal. Levels of adenosine triphosphate were affected most. The ketone body ratio was well maintained. A sharp elevation in levels of aspartate aminotransferase was noted at 2 days but had returned towards normal by 7 days while the prothrombin index and plasma fibrinogen tended to fall. There were inconsistent changes after portal diversion. These data indicate that the hepatic arterial, rather than portal venous inflow is important in the maintenance of porcine hepatic energy charge. This fact has physiological implications, and there is also an important application in the field of liver transplantation, where it may be that the ischaemic liver should be rearterialised first rather than after revascularisation with portal venous blood.

The stimulatory effect of a partially hepatectomized auxiliary graft upon the host liver. Observations on the regenerative response in orthotopic and heterotopic grafts

Transplantation of an intact or partially hepatectomized auxiliary liver graft has been shown to result in a marked regenerative response (as measured by thymidine kinase activity and mitotic index) in the donor liver, apparently associated with rejection. This response was also transmitted to the host (portacaval-shunted) liver which showed a four- to sixfold increment in regenerative response. Livers transplanted by conventional orthotopic techniques also showed a marked regenerative response. The control groups of animals which were subjected to portacaval shunt, portacaval transposition or liver autografting showed a minimal regenerative response. The regenerative response after orthotopic transplantation is an original observation of great relevance to the overall response to liver grafting and may help partly to explain the variable responses to the procedure.

Tympanometry in acute otitis media: prognostic implications

Impedance tympanometry was performed on children with acute otitis media. Most acute tympanograms were classified as either type B (no peak pressure) or positive-pressure tympanograms. A striking difference in outcome was noted between these two groups: the patients with positive-pressure tympanograms were more likely to have normal results with examination at the two-week follow-up than were those with type B tympanograms. There was no difference in outcome between antihistamine-decongestant and placebo regimens evaluated concurrently.