Normothermic ex vivo perfusion of the limb allograft depletes donor leukocytes prior to transplantation.

INTRODUCTION: The donor immune compartment plays a central role in graft rejection of the vascularised composite allograft (VCA) by contributing to 'direct presentation'. Using our limb ex vivo normothermic machine perfusion (EVNP) protocol designed for prolonged allograft preservation, this study aimed to assess whether donor leukocytes responsible for allograft rejection are mobilised from the donor compartment. METHODS: Five genetically different pig forelimbs underwent perfusion via the brachial and radial collateral artery for 6 h after 2 h of cold storage. Oxygenated haemodilute leucocyte-deplete blood was recirculated at normothermia using an extracorporeal perfusion system. Tissue perfusion was evaluated clinically and biochemically via blood perfusate. The temporal kinetics of donor leucocyte extravasation, cytokine secretion and cell-free DNA was characterised in the circulating perfusate. RESULTS: Flow cytometry revealed increasing populations of viable leukocytes over time, reaching 49 billion leukocytes by 6 h. T (3.0 × 109 cells) and B cells (3.1 × 108 cells) lymphocytes, monocytes (2.7 × 109 cells), granulocytes (8.1 × 109 cells), NK (6.3 × 108) and γδ (8.1 × 108) cells were all identified. Regulatory T cells comprised a minor population (1.6 × 107 cells). There was a cumulative increase in pro-inflammatory cytokines suggesting that the donor limb has the capacity to elicit significant inflammatory responses that could contribute to leucocyte activation and diapedesis. CONCLUSION: EVNP not only acts as a preservation tool, but could also be utilized to immunodeplete the VCA allograft prior to transplantation. This has clinical implications to mitigate acute rejection and prevent graft dysfunction and supports the future application of machine perfusion in graft preservation and immune modulation.

Hemodynamic effects of intra-arterial infusions of catecholamines on the canine gastric circulation.

The effects of intra-arterial infusions of epinephrine, norepinephrine, and isoproterenol upon right and left gastric blood flow were studied in anesthetized dogs. Blood flow was measured electromagnetically before and after adrenergic blockade. Infusion of epinephrine (0.05 mug Kg.(-1) min.(-1)) resulted in vasoconstriction (-50 +/- 6 ml. min.(-1)) with autoregulatory escape in the right gastric artery (RGA) and constriction (-41 +/- 8 ml. min.(-1)) followed by significant dilation (+ 56 +/- 10 ml. min.(-1)) in the left gastric artery (LGA). Alpha adrenergic blockade with phenoxybenzamine produced only a dilator response in both RGA and LGA to epinephrine infusion and beta adrenergic blockade resulted in a constrictor response with no autoregulatory escape. Norepinephrine infusions produced a constrictor response of similar magnitude as epinephrine but with little evidence of autoregulatory escape in either RGA and LGA. Alpha adrenergic blockade significantly attenuated this response in both circulations. Isoproterenol is a dilator in both circulations and its response is attenuated only by beta adrenergic blockade. This study demonstrates that the canine stomach has two regionally distinct circulations with the fundus and body exhibiting a greater dilator response than the antrum and pylorus.

Adrenergic mechanisms in the hepatic arterial circulation of baboons.

The effects of intra-arterial injections and infusions of three adrenergic amines upon hepatic arterial blood flow were measured in anesthetized baboons before and after alpha and beta adrenergic blockade with intravenous phenoxybenzamine and propranolol. Injections of norepinephrine or epinephrine caused dose-dependent decreases in hepatic arterial blood flow. These responses were attenuated by alpha adrenergic blockade and were unchanged by beta adrenergic blockade. Injections of isoproterenol caused dose-dependent increases in hepatic arterial flow. These increases were relatively small and were reversed to constriction at low doses and attenuated at high doses of the agonist by beta adrenergic blockade. Intrahepatic arterial infusions of constrictors were unaccompanied by autoregulatory excape. The degree of constriction was attenuated by alpha adrenergic blockade but was not potentiated by beta adrenergic blockade. Intrahepatic arterial infusion of a relatively large dose of isoproterenol was required to evoke a relatively modest, but sustained, increase in hepatic arterial blood flow. This response was not potentiated by alpha adrenergic antagonism, but was attenuated by beta adrenergic blockade. These observations suggest an apparent and relative decrease in beta adrenergic receptor activity in the hepatic arterial bed of the baboon when compared to other regional circulations such as the mesenteric and femoral beds. These beta receptors are relatively resistant to both stimulation and blockade.

Effects of intravenous and intra-arterial infusions of prostaglandin E1 on canine hindlimb blood flow distribution.

Prostaglandin E1 (PGE1) has been used clinically in the treatment of ischemic peripheral vascular disease. However, the preferred route of administration and its influence on the distribution of blood flow to the skin, muscle, bone, and arteriovenous anastomoses ( AVAs ) have yet to be established. Bilateral femoral arterial blood flow was measured electromagnetically in 10 anesthetized adult mongrel dogs (mean weight 16.5 kg). The distribution of femoral arterial flow to the skin, muscle, bone, and AVAs was determined with use of femoral intra-arterial injections of radioactively tagged microspheres (15 +/- 1 mu) before, during, and 1 hour after 20 minutes of intravenous and intra-arterial infusions of PGE1 at 0.1 microgram kg-1 min-1. Intra-arterial infusions caused a significant (P less than 0.003) increase in femoral arterial flow (462 +/- 58 ml X min-1), which was sustained throughout the infusion. The distribution of flow to the skin increased significantly (P less than 0.01) to 24.1 +/- 2.1%, whereas that through AVAs was significantly (P less than 0.05) decreased to 3.2 +/- 0.9%. Femoral arterial blood flow did not change during intravenous infusions; however, there was a significant (P less than 0.01) reduction in the distribution to muscle (41.1 +/- 10.5%) associated with a significant (P less than 0.02) increase in distribution through AVAs (30.8 +/- 11.5%). These data demonstrate the superiority of intra-arterial infusion over intravenous infusions of PGE1 in the canine hindlimb. There was a significant increase in femoral arterial blood flow with increased distribution to the skin and decreased shunting. Femoral arterial blood flow did not change during intravenous infusions; however, a reduction in the distribution of flow to the muscle was accompanied by an increase in shunting.

Heparin decreases ischemia-reperfusion injury in isolated canine gracilis model.

The mechanisms of ischemia-reperfusion injury in skeletal muscle remain controversial. Some investigators have demonstrated that heparin can ameliorate ischemic injury to heart, brain, and renal tissue. We investigated the ability of heparin sodium to decrease ischemia-reperfusion injury in an isolated gracilis muscle model in ten anesthetized mongrel dogs. One gracilis muscle was perfused normally while the contralateral muscle was subjected to six hours of ischemia followed by one hour of reperfusion. Five dogs were given a preischemic bolus of heparin sodium (200 U/kg, intravenously followed by a continuous infusion (15 U/kg/h, intravenously), and five control dogs received no heparin. Quantitation of skeletal muscle ischemia-reperfusion injury was determined by histochemical staining with triphenyl tetrazolium-chloride and computerized planimetry of the infarct size. Results from the ischemic muscle demonstrate a significant beneficial effect of heparinization. The nonheparinized dogs had a 72% +/- 5% infarct size, which was significantly reduced to 24% +/- 8% in the heparinized dogs. The mechanism of this protective effect may be due to heparin's anticoagulant, antiplatelet, or anti-inflammatory action.

Prostacyclin (epoprostenol): its effect on canine splanchnic blood flow during hemorrhagic shock.

Prostacyclin (epoprostenol, prostaglandin I2) is a vasodilator of the splanchnic circulation during normotensive states. To confirm the persistence of its effects after hemorrhagic shock, six anesthetized, previously splenectomized, adult mongrel dogs were subjected to hemorrhagic shock using a modified Wigger's technique in which a mean arterial pressure of 30 mm Hg was maintained until 25% of the shed blood spontaneously returned. The animals were randomly resuscitated with normal saline solution or a similar volume of saline solution containing prostacyclin. Organ blood flow was calculated by measuring the distribution of radioactively tagged microspheres. During shock, blood flows to the liver, small intestine, pancreas, and carcass were reduced. During a 60-minute infusion, prostacyclin selectively caused a significant increase in hepatic arterial blood flow. This improvement in arterial blood flow may prove beneficial in the clinical management of hemorrhagic shock.

Doppler ultrasound, laser Doppler, and perfusion fluorometry in bowel ischemia.

Improved accuracy and objectivity in the evaluation of intestinal viability has been reported by some investigators using Doppler ultrasound, and more recently laser Doppler velocimetry and perfusion fluorometry. To compare the sensitivity and clinical applicability of these techniques, intestinal viability was evaluated by each method in nine 15- to 50-cm loops of small bowel prepared by division of the mesenteric vasculature in five anesthetized dogs. The sensitivity of Doppler ultrasound was 86%, of laser Doppler flow velocity 85%, of laser Doppler index 94%, and of perfusion fluorometry 95%. Though the sensitivity of Doppler ultrasound is significantly less than that of laser Doppler and perfusion fluorometry, this is not unexpected since the latter two techniques are more quantitative than Doppler ultrasound. Clinically, Doppler ultrasound compares favorably with laser Doppler and perfusion fluorometry, and its low cost and simplicity suggest its adjunctive use in the operative setting.

Hemodynamics of an anastomotic arteriovenous fistula.

Various vascular surgical techniques have been employed to increase both graft patency and limb survival when the prognosis for limb salvage in arteriosclerotic patients is especially poor due to a diseased outflow tract. Ibrahim et al described the creation of an anastomotic arteriovenous fistula in distal tibial bypasses as the reconstructive procedure of choice in severely ischemic extremities unsalvageable by more conventional methods. This study presents the hemodynamics of an anastomotic arteriovenous fistula under such circumstances. Four adult mongrel dogs were anesthesized, and a femoral artery and vein were exposed from the groin to the knee. The femoral artery was ligated in midthigh, and the ligated segment was than bypassed using an umbilical vein graft. The distal anastomosis included an arteriovenous fistula. Flow was measured electromagnetically, and pressure was measured with intravascular catheters attached to strain gauges. The creation of an anastomotic arteriovenous fistula rapidly leads to a reversal of flow in the distal artery, distal arterial hypotension, and distal venous hypertension. Its clinical use in contraindicated as a result of our experimental observations.

Hemodynamics of experimental portal venous occlusion in dogs.

The effects of graded occlusion of the portal vein upon hepatic arterial blood flow were studied in anesthetized dogs to evaluate the so-called "reciprocal relationship" between portal venous flow and hepatic arterial flow in maintaining oxygenation of the liver. An obstruction that increased portal venous pressure to 20 mm Hg was accompanied by a transient increase in hepatic arterial blood flow without changing the other hemodynamic parameters. Release of portal venous occlusion was accompanied by a transient fall in hepatic arterial blood flow in this group of experiments. Increasing portal venous pressure to 30 mm Hg caused a gradual but progressive fall in arterial pressure accompanied by a significant fall in hepatic arterial blood flow. With complete obstruction of the portal vein there is a reduction in arterial pressure to the same level of portal venous pressure and a significant and sustained diminution in hepatic arterial blood flow. These observations conflict with previously described theories of a relationship between diminution in portal venous flow and increases in hepatic arterial blood flow.

Clinical use of vasopressin in the management of bleeding esophageal varices.

Vasopressin has been used for 25 years to control bleeding from esophageal varices. Its efficacy is believed to be due to a direct vasoconstrictor activity on splanchnic arterioles and precapillary sphincters, with secondary reduction in portal venous blood flow and pressure. While it has been administered by both the intra-arterial and intravenous routes, the latter has gained favor in the light of laboratory and clinical investigations. The most common complications are cardiovascular, and bradycardia is an early sign of toxicity; adverse effects may be avoided with simultaneous infusion of isoproterenol. Vasopressin has not been shown to prolong survival from esophageal bleeding. It is effective in controlling upper gastrointestinal hemorrhage and is commonly viewed as a means of buying time to prepare the patient for shunt surgery. Vasopressin infusion may reduce both operation time and blood loss during shunt surgery. New analogs of vasopressin presently under investigation may facilitate its administration and reduce morbidity.

Differential hyperemic responses following femoral arterial and thigh cuff occlusion in the canine hindlimb.

The hyperemic response following arterial reconstruction is variable. To further evaluate this response, arterial blood flows in the canine hindlimb were compared following isolated femoral arterial occlusion and after thigh cuff tourniquet occlusion, which also obstructs collateral circulation. Arterial occlusion and tourniquet occlusion produced significant (P less than 0.05) increases in femoral arterial flow after all intervals of occlusion, except following 30 minutes of isolated arterial occlusion. Isolated arterial occlusion and tourniquet occlusion produced comparable hyperemic responses through five minutes of occlusion. However, tourniquet occlusion produced a significantly greater increase (P less than 0.05) in femoral flow when occlusions exceeded five minutes. These data suggest that the extent of collateralization may moderate the postobstructive hyperemic response following aortic and femoropopliteal reconstruction. The collateral recruitment during isolated arterial occlusion may be responsible for a diminished hyperemic response with time, while obstruction of the collateral circulation during tourniquet occlusion may result in a greater hyperemic response.

Appendicitis versus pelvic inflammatory disease. A diagnostic dilemma.

In order to determine whether any clinical or laboratory findings were helpful in differentiating acute appendicitis (AP) from acute pelvic inflammatory disease (PID), this retrospective study was undertaken. Records of all female patients 12 to 50 years of age, undergoing laparotomy with a preoperative diagnosis of AP over the past 15 years, were reviewed and pertinent data recorded. In comparing AP (n = 106) with PID (n = 39), longer duration of symptoms, relationship of onset of pain to the menstrual cycle, and frequent requests for gynecological consultation distinguished the PID from the AP cases. Although complete reliance cannot be placed on any clinical or laboratory finding in differentiating AP from PID, the final satisfactory outcome justifies laparotomy when the diagnosis cannot be established by other means.

Treatment of frostbite with intra-arterial prostaglandin E1.

Prostaglandin E1 (PGE1) is a vasodilator that inhibits platelet aggregation. Its use has been effective intra-arterially in treating ischemic peripheral vascular disease. Its potentially beneficial effect in treating frostbite injuries has not been studied and prompted this investigation. A standard frostbite injury was induced by immersing the hindlimbs of New Zealand white rabbits in an ethylene glycol bath maintained at -15 C. Forty animals were separated into eight equal groups (N = 5). Groups I through V were allowed to slowly rewarm at room temperature (21-22 C), while Groups VI through VIII underwent rapid rewarming in a water bath at 42 +/- 1 C. Groups I and VI received no further treatment. Groups II and VII received intra-arterial bolus injections of saline. Group III received intra-arterial bolus injections of reserpine (2.5 X 10(-3) mg/kg-1). Group IV received intra-arterial bolus injections of PGE1 (10(-1) micrograms/kg-1). Groups V and VIII received 3-hour intra-arterial infusions of PGE1 (10(-1) micrograms/kg-1 min-1). Tissue loss was graded numerically after 30 days. Group V (slow rewarming plus 3-hour PGE1 infusion) had significantly (P less than 0.5) less tissue loss than Group I (slow rewarming alone) and Group II (slow rewarming plus saline). Group V was not significantly different from Groups VI through VIII (rapid rewarming). Group III (slow rewarming plus bolus reserpine) and Group IV (slow rewarming plus bolus PGE1) were not significantly different from Group I (slow rewarming alone). The data suggest a clinical application for the use of PGE1 in frostbite patients who have not undergone rapid rewarming.

Acute ischemia-reperfusion injury in the canine hindlimb.

A canine arterial ligation preparation was used to produce whole limb ischemia-reperfusion injury. Alterations in the distribution of arterial blood flow as well as the morphology of skeletal muscle ischemia-reperfusion have not been investigated completely in this setting. Five anesthetized adult mongrel dogs underwent multiple infrarenal aortic branch ligations; one randomly selected hindlimb was subjected to six hours of ischemia and two hours of reperfusion, while the opposite limb served as control. Distribution of arterial blood flow was analyzed by injection of radiolabeled microspheres. Electromagnetically measured femoral arterial blood flow was 92 +/- 10 ml/min during control, and increased significantly (p less than 0.05) to 254 +/- 94 ml/min during reperfusion. Flow distribution to skin, muscle, and bone was 9 +/- 2%, 68 +/- 7%, and 8 +/- 1% during control, and 7 +/- 3%, 65 +/- 8%, and 9 +/- 4% after reperfusion, which did not represent significant changes. Arteriovenous shunting was 11 +/- 4% during control, and was 13 +/- 5% during reperfusion, which was not significantly different. Subcellular injury in the ischemic and reperfused hindlimb was demonstrated by light and electron microscopy. These findings further characterize whole limb ischemia-reperfusion injury in the canine hindlimb.

Effectiveness of a program of information and support for myocardial infarction patients recovering at home.

The impact of patient education follow-up by telephone on the knowledge of the postmyocardial infarction (MI) patient was investigated in this study. On the basis of Orem's self-care framework, subjects' levels of knowledge in six criterion areas were assessed according to measurement criteria developed by Horn and Swain. Fifty-one subjects from the total population of MI patients admitted to the coronary care unit of the study hospital during the period of research who met study criteria were randomly assigned to experimental and control groups. Statistically significant differences (p less than 0.05) were found in the knowledge level of the experimental group in the areas of the disease, its effects, related self-care measures, recommended exercises, and all teaching areas together. Although significant differences were not found in the teaching areas of therapeutic diet, medications, physical activity restrictions, and recommended rest, a higher mean was produced for the experimental group in all but one area. These findings demonstrate that a telephone teaching program for MI patients 6 to 8 weeks after hospital discharge can be effective in increasing knowledge relative to the disease, self-care, and therapeutic regimen.

A critical analysis of clerkship grading procedures.

Rating of clinical performance and examination scores are employed to establish the final grade of students undertaking the surgical clerkship. This retrospective study was undertaken to determine whether there is a correlation between these two grading procedures in evaluating students. Grades for clinical performance and the scores obtained on the written examination-either intramural (IM) or extramural (EM)-by each student for 20 recent consecutive 12-week surgical clerkship rotations were tabulated and the correlation (regression) coefficients of the two grading systems calculated in each rotation. By means of a questionnaire, grading methods employed in 60 randomly selected US medical school surgical departments were requested (55 responded). Correlation coefficients indicate that there is no statistical correlation between the grades of the clinical performance and the written examination in the majority of rotations (80 percent IM and 70 percent EM).GRADING PROCEDURES USED TO DERIVE THE FINAL GRADE AND THE MEANS OF REPORTING IT IN OTHER MEDICAL SCHOOLS ARE AS FOLLOWS: 41 percent (23/55) used the clinical performance and written examination; 38 percent (21/55) used the clinical performance, written examination, and oral examination; and 20 percent (9/55) used the clinical performance only. For the final grade, 91 percent (50/55) subscribed to honors, pass, and fail categories and 9 percent (5/55) preferred a numerical grade.

Impact of an instructional program on nurses' accuracy in capillary blood glucose monitoring.

This experiment examined the accuracy of capillary blood glucose monitoring using the visual glucose oxidase strip (Chemstrip) procedure. Also, the effects of a certification program for nurses on the accuracy of glucose oxidase strip monitoring by registered nurses were analyzed. Seventy nurses and 123 patients participated. Data were collected from nurses' recordings of visual Chemstrip procedure results and from the concurrent laboratory blood glucose determinations for 3 months. The data included 70 Chemstrip recordings and 70 concurrent laboratory blood glucose recordings in the experimental group and 68 Chemstrip and 68 concurrent laboratory glucose recordings in the control group. Data analysis revealed that the accuracy of the nurses' performance of the glucose oxidase strip procedure was inadequate. A certification program did, however, dramatically improve the accuracy of the procedure. Proximity of time between the certification program and the performance of the glucose oxidase strip procedure did not affect accuracy.

Visions realized and dreams dashed: Helen Penhale and the first basic integrated baccalaureate program in nursing in the west, at the University of Alberta 1952-1956.

The first basic degree program in nursing in Canada was established at the University of British Columbia in 1919. This program and those that followed elsewhere were of the non-integrated form, wherein a diploma program offered by a hospital was supplemented by university courses in the arts, humanities, and sciences. In 1942 an innovative basic baccalaureate program in nursing was established at the University of Toronto; courses in nursing, given by the university, were offered in conjunction with university courses in other subjects. Only two other attempts were made to set up integrated programs in Canada prior to release of the Report of the Royal Commission on Health Services of 1964; McMaster University established a program in 1946, and, in an attempt that was ultimately unsuccessful, a program was established at the University of Alberta in 1952. The purpose of this study was to examine the conditions surrounding the initiation and termination of a basic degree program in the 1950s at the University of Alberta, in order to understand the key issues in the movement to establish basic university degree programs for nurses, and the gender discrimination relative to nurses and nursing students that has prevailed in health and education. Although the conflict at the University of Alberta was a very difficult one for the nurses involved, and although the Director who had the temerity to establish the program relinquished her position when the program was summarily terminated, this episode in Canadian nursing history provides insight into the climate in which baccalaureate nursing education existed and into some of the issues relative to its development.

Peri-partum posture and behaviour of gilts and the location of their piglets in lines selected for components of efficient lean growth.

Peri-partum posture and behaviour of gilts from lines selected for different components of efficient lean growth were studied to determine if behavioural changes may have been associated with the observed responses in reproductive performance. The proportions of time that gilts expressed defined posture and behaviour traits and the locations of their piglets were determined from video recordings of observations made at 5min intervals in the period extending from 2h pre-farrowing to 2h post-farrowing. The 137 gilts studied were from four pairs of Large White lines which had been divergently (high and low) selected for either daily food intake (DFI), lean food conversion efficiency (LFC), lean growth rate on ad libitum feeding (LGA) or lean growth rate on a restricted feeding scale (LGS).Almost all the significant (P<05) changes occurred in the LGS pair of lines. In the pre-farrowing period, relative to the low LGS gilts, high LGS gilts spent a higher proportion of their time lying on their sides (0.92 versus 0.69), and less time in the upright postures of standing, sitting or lying on their bellies (0.08 versus 0.33) and engaging in nesting behaviour (0.02 versus 0.10). During farrowing, high LGS gilts again lay on their sides more often than low LGS gilts (0.96 versus 0.80) and were upright less often (0.04 versus 0.20). High LGS gilts changed posture less often than low LGS gilts (0.05 versus 0.31) but were more often alert (0.79 versus 0.61). During farrowing, high LGS piglets were seen less often at their mother's head, back and vulva or at the creep than low LGS piglets (0.06 versus 0.15). Post-farrowing, there were no significant differences between the lines, almost all gilts lying on their sides with their piglets at the udder. Divergent selection for components of efficient lean growth rate on ad libitum feeding was not associated with consistent responses in gilt posture and behaviour or in piglet location. Selection for high lean growth on restricted feeding had effects on gilt posture and behaviour which may have been beneficial to her welfare and that of her piglets.

Utilization of hospital services by the elderly: geriatric crisis in one Canadian single payer system.

As the number and proportion of elderly persons in the Canadian population increase, utilization of health services by the elderly becomes a growing concern for health service insurers, financial managers and policy makers, as well as for care providers. The purpose of this paper is to present the results of a study to analyse the use of hospital services by the elderly in Alberta since the introduction of a universal single payer health care insurance system in 1970. The study period coincides with the implementation of publicly-financed comprehensive medical and hospital insurance programmes for all Alberta residents, making it possible to perform historical and population-based utilization analyses. Thus the data used for the study included all hospital discharge abstracts generated by all Alberta hospitals from 1971 to 1991. Trends in hospital service utilization by the elderly in terms of total number of separations, patient-days, and per case measures such as average length of stay as well as per capita utilization rates were reviewed to identify utilization patterns over the study period. Further, relative per capita utilization measures, in comparison with the base year (1971), age group 15-44, male, metropolitan residents, were derived and historical trends identified. A series of regression analyses were carried out to estimate the effects of age, sex and origin on utilization rates. In addition, for the period of 1984-1991, Diagnosis Related Groups (DRG) case weights were used to measure per capita and per case rates and to analyse historical relative utilization rates over the 8-year period. In general, there has been a significant decline in hospital utilization by Albertans under the publicly-financed single payer system, but utilization rates for elderly have remained high, resulting in high relative utilization rates in comparison with other age groups. It was also noted that per capita utilization rates for rural residents were substantially higher than urban residents. It appears that these higher utilization rates by the elderly and rural residents in combination with tight bed and financial control by the government have been causing significant bed shortage problems for non-elderly elective patients in urban areas.