The evolution of the concept of brain death

The definition of death has taken many forms throughout history. Because of advances in critical care and developments in transplantation, a new definition of death has evolved over the past 30 years. The first accounts of brain death were published in 1959, in relative obscurity. They were only considered to be of academic interest. In the mid-1960s, advances in transplantation and the need for viable organs started debate about the use of "brain-dead" patients as organ donors. Conceptual advances by the ad hoc committee of the Harvard medical school and the use of angiography and the electroencephalogram both advanced and confused the issue. Acceptance by the medical community remained divided. During the 1970s, brain-stem death was proposed as the true definition of death by pioneers in the United States and Britain. In the 1980s, the clinical diagnosis of brain-stem death was officially accepted and many of the controversies subsided.

Initial nonfunction in cadaveric renal transplantation

Patients who receive a kidney transplant that does not function immediately have more complications and decreased graft survival than patients whose allografts function immediately. To determine the causes of initial nonfunction (INF), the authors reviewed 188 consecutive cadaveric kidney transplants performed between 1985 and 1988 at the University Hospital, London, Ont. Data were collected on 16 putative risk factors for INF, which were divided into three categories: donor, recipient and technical. INF was defined as the need for dialysis within 7 days of transplantation. Forty-eight (26%) of the 188 allografts had INF, 6 of which never functioned. Univariate analysis identified five variables associated with increased risk of INF: no donor dopamine use, back-table flush, single-organ retrieval, exchanged kidney and prolonged cold ischemic time. Multivariate analysis, however, identified only three variables associated with INF: cerebrovascular accident as the cause of donor death, no donor dopamine use and single-organ retrieval. The authors recommend (a) low-dose dopamine therapy for all donors and (b) multiorgan retrieval to produce quality kidneys for transplantation.

The effect of cyclosporine and liver autotransplantation on bile flow and composition in dogs

Following liver transplantation bile formation may be influenced by hepatic denervation and cyclosporine therapy. To better establish any effect of liver transplantation on bile secretion, 6 mongrel dogs were studied: 3 underwent liver denervation by a modified autotransplantation procedure and insertion of a Thomas cannula to create a chronic duodenal fistula; 3 others had cholecystectomy and the duodenal cannula placement without manipulating the liver. One month after surgery, two control studies were done, one week apart. Then oral cyclosporine was given in doses of 5, 15, and 50 mg/kg/day for consecutive 1-week periods each. Twice on each cyclosporine regimen, after 4 and 7 days of therapy, the common duct was cannulated and bile collected for 5 h; animals were awake and fasted. The first 3 h of bile collection established basal conditions; flow was then stimulated with consecutive hour-long taurocholate infusions at 1 and 2 mumol/kg/min. In all dogs, bile flow increased as the cyclosporine dose increased, under both basal and bile salt-stimulated conditions. The increased flow primarily resulted from increased bile salt-independent flow. Cyclosporine had no effect on bile salt, bilirubin, or cholesterol secretion. Phospholipid secretion, however, decreased significantly in a dose-related manner with increasing cyclosporine in the dogs with autotransplanted livers, but not in the nontransplanted dogs. This decrease in phospholipid secretion resulted in a significant increase in the calculated cholesterol saturation of bile. Thus, cyclosporine administered orally is not cholestatic but rather increases bile flow independent of any change in bile salt secretion. Cyclosporine reduced phospholipid secretion in autotransplanted dogs, possibly related to denervation of the liver. The resultant change in biliary composition may pose a risk factor for gallstone formation.

Mechanisms of rejection during OKT3 therapy: propagation and characterization of CD3 resistant allospecific cytotoxic T cells from a rejecting liver allograft

Allograft rejection remains the single largest impediment to success in the field of transplantation. While OKT3 therapy has proven to be a significant advancement, many grafts are still lost. Late treatment, subtherapeutic OKT3 levels, anti-OKT3 antibodies, and OKT3-induced class II antigen expression are possible explanations. To determine the mechanism of OKT3 resistant rejection we propagated and characterized infiltrating T cells from the biopsy of a liver transplant patient who was rejecting while on prophylactic OKT3. The T lymphocytes demonstrated allospecific proliferation and interleukin 2 (IL2) production and showed a high degree of cytolysis of donor splenocytes. CD3 epsilon monoclonal antibodies (Mab) in concentrations up to 100 micrograms/ml did not inhibit lysis. In contrast, T lymphocytes derived from rejecting allografts of patients receiving cyclosporine and prednisone were readily inhibited from killing by CD3 epsilon Mab at doses of 1 microgram/ml. Furthermore, allospecific proliferation and IL2 production were not inhibited in the OKT3-treated patient by the addition of CD3 epsilon MaB. Incomplete modulation of the CD3-TCR complex was noted after a 72-hr incubation with CD3 epsilon Mab. The T cells did demonstrate other intact CD3-mediated functions such as a rise in intracellular calcium and CD3-dependent cytotoxicity. These results should alert clinicians that CD3 resistant cytotoxic T cells can emerge during OKT3 therapy and may cause rejection. Immunotherapy that targets additional cell surface structures may be of benefit.

Human orthotopic small intestine transplantation: radiologic assessment

The authors describe the postoperative anatomy and review the radiologic examinations of five patients who underwent orthotopic small intestine or combined orthotopic liver and small intestine transplantation. Mucosal thickening of the transplanted intestine was demonstrated on the first postoperative contrast material-enhanced images and was due to submucosal edema. This resolved within 2 weeks in the long-term survivors. Bowel peristalsis appeared normal as early as 31 days after transplantation. Contrast-enhanced examinations of the intestine were useful to exclude surgical complications such as anastomotic leaks or strictures, but were insensitive for biopsy-proved cytomegalovirus enteritis or rejection.

The importance of class I and class II HLA in cadaveric renal transplantation

The importance of avoiding mismatches (MM) at Class I and Class II HLA antigens in cyclosporine-treated renal allograft patients is controversial. In order to assess the role of HLA, 200 consecutive cadaveric renal allografts over a 4-year period were analysed. All patients received cyclosporine/predinisone immunosuppression and 75% were induced with ALG. Minimum follow-up period was one year. HLA A, B, DR, DQ, and DRw52/53 typing were available on 77-100% of allografts. A beneficial effect was noted at the HLA A locus. One-year survival was 87.2% in the 0 and 1 HLA A MM group combined vs 73.8% in the 2 HLA A MM group (p less than 0.05). The mean creatinine level at one year was also lower in the 0 plus 1 MM vs 2 MM group: 152.8 mumol/L vs 184.8 mumol/L, respectively (p less than 0.05). Significantly fewer rejection episodes occurred in the 0 and 1 HLA DQ MM group combined vs the 2 MM group. Steroid-resistant rejection episodes (SRRE) were not associated with the number of HLA MM. Patients who had an SRRE had significantly higher mean current and historical peak panel reactive antibodies (PRA) than patients who did not have SRRE. These results indicate that avoiding mismatches at the HLA A locus may improve renal allograft survival, and matching at HLA DQ may predispose patients to a more quiescent post-transplant course. The degree of preoperative sensitization may be an important etiologic factor in SRRE.

The effect of cyclosporine A on bile secretion in dogs

Cyclosporine A is reported to cause cholestasis, but the evidence is confounded by anesthesia and surgery used in acute experiments. To better investigate the effect of cyclosporine on the liver, bile output was directly measured in three cholecystectomized dogs by cannulating the common duct through a chronic duodenal fistula. Control studies were done 1 month after surgery. Cyclosporine in oral doses of 5, 15, and 50 mg.kg-1.d-1 was then given for consecutive 1-week periods. Twice during each study period, bile output was measured for 5 h in fasted, awake animals: 3 h to establish basal conditions, followed by 2 h of taurocholate infusions at 1 and then 2 mumols.kg-1.min-1. Under basal conditions, bile flow rose with each dose of cyclosporine, increasing 63, 127, and 179% above control with cyclosporine 5, 15, and 50 mg.kg-1,d-1, respectively. Bile flow increased similarly during taurocholic acid stimulation. Cyclosporine had no effect on bile salt or bilirubin secretion. In this chronic dog model isolated from other causes of cholestasis, cyclosporine did not induce cholestasis but rather caused a dose-related choleresis without any change in bile salt secretion.

Predicting the outcome of exploratory laparotomy in ICU patients with sepsis or organ failure

Critically ill patients with sepsis and/or organ failure are difficult to assess. They are often comatose or on steroids and many nonspecific findings such as fever, positive blood cultures, or septic shock which may suggest intra-abdominal sepsis are far from diagnostic. To determine whether decision making regarding the use of laparotomy in these patients could be improved upon, we reviewed our experience with consecutive intensive care unit patients who had laparotomy and we related laparotomy outcome to clinical signs and symptoms. Seventy-three per cent of the 100 laparotomies reviewed were positive for intra-abdominal sepsis. A discriminant function analysis revealed that eight factors in combination predicted laparotomy outcome. However, the overall accuracy of the discriminant function prediction (76.8%) offered little improvement over the policy in place for performing laparotomies in this group of patients at the participating hospitals during the time period of our investigation.

Abomasal displacement in a changing husbandry and its treatment

A description is given of the area in south Argyll within which the incidence of abomasal displacement has been followed, together with the factors involved. Over the period 1970 to 1983 a radical change took place in methods of feeding and housing dairy cattle. Over the same period, a comparison of the milking cow population and the number of cases of abomasal displacement occurring annually indicated a reduced incidence of the condition. It is suggested that this is related to the changes in farm husbandry. The methods of treatment used in this area are also discussed.