External stabilization of the anterior cruciate ligament deficient knee during rehabilitation

Using cadaveric specimens, we studied the effect of ACL deficiency upon anterior tibial translation during extension of the knee joint. Five knees were loaded via the quadriceps mechanism until flexion angles of 10 degrees, 25 degrees, 40 degrees, and 60 degrees were attained. At each angle, the anterior-posterior position of the tibia was documented with biplane radiography, both before and after division of the ACL. In every specimen, anterior tibial translation increased with loss of the ACL and was greatest at 25 degrees of flexion, where an average displacement of 3.3 mm was observed. Subluxation was not significant at flexion angles exceeding 60 degrees, regardless of ACL deficiency. We also examined the effect of an external restraining force on tibial subluxation in the ACL deficient knee. Posteriorly directed forces of 0 N, 45 N (10 pounds), 90 N (20 pounds), 135 N (30 pounds), and 225 N (50 pounds) were applied to the tibia at the level of the tibial tubercle. Anterior subluxation was eliminated through application of forces ranging from a maximum of 106 N (23.6 pounds) at 10 degrees to only 13 N (2.9 pounds) at 60 degrees.

Action of cefoxitin and cefamandole on human neutrophil function

Polymorphonuclear neutrophilic leukocyte chemotaxis was examined in vitro in the presence to two new antibiotics: cefamandole and cefoxitin. Results indicate that cefamandole inhibited neutrophil chemotaxis to a significant degree only at high antibiotic concentrations of 100 microgram/ml (P less than 0.01) and has no significant effect at normal serum therapeutic range. Cefoxitin was found to produce a 43% inhibition (P less than 0.01) of human in vivo neutrophil chemotaxis at antibiotic concentrations of 100 microgram/ml and have a minimal inhibitory effect (1 approximately 9%) at low concentrations (1 approximately 5 microgram/ml). Both cefamandole and cefoxitin had no significant effect on opsonophagocytosis.

The immunosuppressive effects of the in vivo administration of endotoxin as influenced by macrophages

It is well documented that endotoxin can have immunosuppressive effects on lymphocytes and induce the production and secretion of monokines which act on the lymphocytes. To delineate the interaction between macrophages and lymphocytes more clearly, 0.15 mg of lipopolysaccharide (LPS) (E. coli 0111:B4) was injected into Hartley guinea pigs intraperitoneally twice a day for 7 days (saline for control group). Seven days after the last injection, spleens were taken and lymphocyte proliferation was determined in the presence and absence of macrophages. When macrophages were present, there was a significant suppression of lymphocyte proliferation when PHA and PWM were used as mitogens. There was no suppression of proliferation when the macrophages were removed. Splenic macrophages were also cultured in the presence and absence of LPS and their supernatants analyzed for PGE2 and TXB2. There was no significant difference between the endotoxin and control groups for PGE2 or TXB2 production in the presence and absence of LPS. However, the endotoxin group had significant decreases in serum levels of C3 postinjection of endotoxin which could indicate C3 degradation by LPS. Taken together these results give further evidence that macrophage products in addition to PGE2 can inhibit lymphocyte proliferation. C3 degradation products could possibly stimulate macrophages to produce inhibitors of lymphocyte proliferation or induce suppressor cells.

Augmentation of donor-specific transfusion and cyclosporine effects with dietary linoleic acid

Increased prostaglandin production is a possible mechanism for the immunosuppressive effects of both cyclosporine and blood transfusions. Therefore, dietary supplementation with linoleic acid, a prostaglandin precursor, combined with either modality could act synergistically. Intraabdominal cardiac allografts were performed from Buffalo rat donors to Lewis recipients. Transplant recipients received a single donor-specific transfusion, low-dose cyclosporine (CsA, 1 mg/kd/d x 7 days), dietary supplementation with linoleic acid (LA, 16% of total calories) or a combination of the three modalities. CsA, DST or LA alone significantly prolonged allograft survival. Both CsA and LA acted synergistically with DST in further prolongation of survival--however, animals receiving all three modalities achieved 100% long-term survival. Augmentation of transfusion- and cyclosporine-induced immunosuppression with dietary prostaglandin precursor is possible.

Effects of combination of tumor necrosis factor alpha and chemotactic peptide, f-Met-Leu-Phe, on phagocytosis of opsonized microspheres by human neutrophils

Pretreatment of normal, human neutrophils with 8 units/ml of TNF-alpha followed by treatment with 10(-8) M FMLP resulted in a synergistic effect of the combination of the two mediators on the enhancement of the phagocytic capacity of the cells. This enhancement of phagocytosis occurred without an additional increase in the upregulation of C3b receptors (CR1) beyond that caused by each mediator alone. Pretreatment of the cells with 8 units/ml of TNF-alpha followed by 10(-6) M FMLP resulted in an additive effect of the mediators on neutrophil phagocytosis, again without an additional up-regulation of CR1. This additive effect resulted in an increase in phagocytic capacity of the neutrophils greater than that obtained by treatment of the cells with 10(-6) M FMLP alone, which heretofore has resulted in the greatest enhancement of phagocytic capacity obtained by any pretreatment condition. These synergistic and additive effects of the combination of mediators could be of great importance in host defense against bacterial infections and have important implications regarding the mechanisms of receptor upregulation and phagocytosis.

Histocompatibility testing predicts acute rejection risk in early corticosteroid withdrawal regimens

Histocompatibility testing has been shown to predict acute rejection risk in steroid-based immunosuppression. However, little evidence exists of its ability to predict acute rejection risk in corticosteroid-free patients, with no evidence in early corticosteroid withdrawal (CSWD) under modern immunosuppression. The purpose of this study was to evaluate the ability of histocompatibility testing to identify patients at high risk for acute rejection after early CSWD.

METHODS

One hundred eighty-one patients were entered into six IRB-approved early CSWD regimens. Histocompatibility testing included serologic PRA, flow cytometric PRA testing by Class I and Class II MHC beads, and B cell crossmatching with pronase treatment. All rejection episodes were biopsy proven, and grading was assigned using Banff criteria. Influence of individual tests was examined using Chi square univariate and multivariate logistic regression analysis.

RESULTS

Median follow-up was 23.5 months (range 7-48 months). Of 181 patients, 16% were repeat transplant recipients, 36% received deceased donor renal transplants, 48% received living related donor renal transplants, and 16% received living unrelated transplants. Overall patient survival was 97%, and death-censored graft survival was 96.5%. Acute rejection rates in the entire follow-up period were 17.7%. 12.4% in primary transplant recipients and 37% in repeat transplant recipients. Multivariate analysis revealed that HLA AB and DR locus mismatching were associated with increased acute rejection risk. Similarly, serologic PRA analysis predicted acute rejection risk; however, flow cytometry crossmatching did not predict acute rejection risk. The greatest single influence on acute rejection risk appeared to be a flow cytometric B cell crossmatch (7.94-fold increased risk). In conclusion, histocompatibility testing can identify patients at high risk for acute rejection following early CSWD. HLA matching, serologic PRA testing, and flow cytometry-based B cell crossmatching can all be used to predict acute rejection risk.

Effect of vitamin A in enteral formulae for burned guinea-pigs

A burned guinea-pig model (30 per cent body surface area) was used to study the effects of dietary vitamin A. Sixty-five female guinea-pigs were infused enterally via gastrostomy feeding tubes with identical formulate (175 kcal/kg/day, 20 per cent of calories as protein) containing varying amounts of vitamin A. Groups I, II, III and IV received formulae containing 0, 10,000 iu (approximately equivalent to the guinea-pigs' RDA), 50,000 iu (5 x RDA) and 250,000 iu (25 x RDA) of vitamin A per litre, respectively. After 14 days of tube feeding, the animals were killed. Group I animals had evidence of vitamin A deficiency including low haemoglobin levels, lower red blood cell counts and lower caecal mucosal weight. Findings of hypervitaminosis A were observed only in animals given the highest dose of vitamin A (25 x RDA). These were elevated serum alkaline phosphatase and complement C3 levels and enlarged adrenal glands. Group IV also showed defective cell-mediated immunity as reflected by reduced delayed cutaneous response to dinitrofluorobenzene. In a second experiment groups I, II, III and IV were given formulas containing 0, 1 x RDA, 5 x RDA, and 10 x RDA of vitamin A respectively for 14 days. Through postburn days 12 to 14 they were injected subcutaneously with 3 x 10(8) of Staphylococcus aureus once daily. On postburn day 15 the animals were killed and the numbers of viable bacteria at each injection site were counted. No significant differences were observed in viable bacterial numbers between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Production and release of C3 by cultured monocytes/macrophages isolated from burned, trauma, and septic patients

The release of C3 under various conditions by cultured monocytes/macrophages isolated from burned, trauma, and septic trauma patients was determined. When monocytes were cultured for up to 14 days there was no difference in production and release of C3 by normals and patients; C3 production rose slowly at first then rose rapidly from 8-14 days of culture. C3 production continued for up to 28 days of culture. When lymphocytes were present with the monocytes for the first 24 hr of culture there were differences in C3 production by normal and patient cells at various times of culture. There were differences in C3 release by patients' 24 hour-cultured cells at certain postburn and injury days. Macrophages from burned patients released less C3 than normal cells and macrophages from septic trauma patients released more C3 than normal cells.

Clinical correlations of cyclosporine-specific and -nonspecific assays in stable renal transplants, acute rejection, and cyclosporine nephrotoxicity

Accurate and early diagnosis of the cause of renal transplant dysfunction is important in successful patient management. Controversy exists as to whether a cyclosporine-specific or -nonspecific method is more predictive of clinical events. In an attempt to answer this question, all episodes of acute renal dysfunction were reviewed in 322 stable renal transplant recipients over a 20-month period. To diagnose the cause of each episode of renal dysfunction, an analysis was made of patient demographics; weight; serum creatinine; cyclosporine dose; cyclosporine level, using a specific method--high-performance liquid chromatography (HPLC)--and a nonspecific method--fluorescent polarization immunoassay (FPIA); changes in cyclosporine dose; renal biopsy; and response to any therapeutic intervention. There were 138 patients, who developed 279 episodes of renal dysfunction. Causes of renal dysfunction were cyclosporine-related (n = 103), acute rejection (n = 63), extracellular fluid volume depletion (n = 27), other (n = 59), and unknown (n = 27). The mean HPLC cyclosporine level was significantly different in patients with acute cyclosporine toxicity (p < 0.001) and patients with acute rejection (p < 0.001) when compared to those with stable renal function; the mean FPIA cyclosporine levels were not significantly different between the three groups. However, a larger percentage of patients with rejection were subtherapeutic when measured by HPLC, while a higher proportion of patients with nephrotoxicity were above the therapeutic range measured by FPIA.(ABSTRACT TRUNCATED AT 250 WORDS)

CO2 surgical laser for treatment of stress urinary incontinence in women: a randomized controlled trial

BACKGROUND

Stress urinary incontinence is a common condition that can be treated conservatively and/or surgically. Given the risks of surgery, developing effective nonsurgical treatment options would be beneficial. Some studies have suggested that laser therapy may improve or cure stress urinary incontinence. However, there is a lack of sham-controlled randomized controlled trials to judge treatment efficacy.

OBJECTIVE

This study aimed to compare the effects of CO₂ vaginal laser vs sham therapy for treating stress urinary incontinence.

STUDY DESIGN

This was a multicenter, participant-blinded, sham-controlled, parallel group (1:1) superiority randomized controlled trial performed in outpatient clinics in 2 hospitals. We included women aged 18 to 80 years with objective and subjective stress urinary incontinence. Participants had undertaken or declined supervised pelvic floor muscle training. Intervention was performed using a CO₂ fractionated vaginal laser. Participants underwent 3 treatments, 4 weeks apart, with increasing energy and density settings. Sham treatment was performed using an identical technique with a deactivated pedal. The primary outcome was the subjective stress urinary incontinence rate (proportion with leak with cough, sneeze, or laughter) at 3 months after completion of treatment. Secondary outcomes included objective stress urinary incontinence, change in the disease-specific patient-reported outcomes, health-related quality of life, and adverse effects. Categorical outcomes were compared using the chi square test and continuous outcomes using analysis of covariance, adjusting for the baseline score.

RESULTS

There were 52 participants who received laser and 49 who received sham treatment. One participant in each group withdrew from the study before the endpoint, and 2 participants in the laser group did not participate in the follow-up visits. Participant mean age was 53 (34-79) years. Mean body mass index was 26.1 (18.1-49.6); 90% were vaginally parous. At 3 months, there was no difference between the sham and active treatment arm in subjective stress urinary incontinence (46 [96%] vs 48 [98%]; relative risk, 0.98 [95% confidence interval, 0.91-1.05]; P=.55) or in objective stress urinary incontinence (37 [80%] vs 33 [80%]; relative risk, 0.99 [95% confidence interval, 0.81-1.23]; P=.995). Patient-reported outcomes and health-related quality of life were also comparable between the groups. Vaginal bleeding occurred in 3 participants after laser and 1 participant after sham treatment. Pain during treatment did not differ between laser and sham treatment.

CONCLUSION

We were unable to show an improvement in stress urinary incontinence after CO₂ vaginal laser therapy compared with sham treatment.

Efficacy of OKT3 as primary therapy for histologically confirmed acute renal allograft rejection

BACKGROUND

OKT3 is often used as primary treatment for acute renal allograft rejection. In a retrospective study, we sought to determine the efficacy of OKT3 as a first-line agent in reversing histologically confirmed acute renal allograft rejection.

METHODS

Patients with mild to moderate, moderate, or severe acute cellular and acute vascular rejection who had not received any other anti-rejection treatment were included in this analysis. A total of 88 patients, who received OKT3 between 1987 and 1995, fulfilled these criteria.

RESULT

Seventy of these patients were renal transplant recipients, and 18 were combined kidney and pancreas transplant recipients. The median time to the diagnosis of rejection from transplantation was 32 days (range, 6 days to 13 years). On histology, 6 were graded as mild to moderate, 36 as moderate, 29 as moderate to severe, and 17 as severe rejection. The mean baseline serum creatinine was 1.62 mg/dl (range, 0.7-10.1 mg/dl), and the mean serum creatinine at the time of diagnosis of rejection was 2.60 mg/dl (range, 1.4-12.7 mg/dl) (P=<0.0001). The mean duration of OKT3 treatment was 11.2 days (range, 8-18 days). The mean serum creatinine at the end of OKT3 treatment was 1.73 mg/dl (range, 0.6-5.0 mg/dl; P=0.24 compared with baseline serum creatinine). Rejection was reversed in 86 (98%) patients. Graft survival at 1 year after OKT3 therapy was 87.5% (77 of 88). At a mean follow-up of 38 months, 8 patients had died and 26 grafts were lost. The mean serum creatinine level in the 64 patients with a functioning graft was 1.76 mg/dl (range, 0.8-4.0 mg/dl) at the last follow-up.

CONCLUSION

OKT3 when utilized as first-line therapy reversed 98% of the acute rejection episodes, with a 1-year post-OKT3 graft survival of 87.5%.

Effect of a diet rich in branched chain amino acids on severely burned guinea pigs

This study was performed to investigate the effects of dietary supplementation with branched-chain amino acids (BCAA) for postburn nutritional management. Seventy-one burned guinea pigs (30% TBSA) with previously placed catheter gastrostomies were divided into six groups. The first, second, and third groups received 10%, 20%, and 30%, respectively, of total calories as whey protein. The other three groups received BCAA supplementation to increase BCAA to 50% of total amino acids, compared to 21.5% BCAA content in whey protein. Groups I and IV received isonitrogenous intake, as did groups II and V, and III and VI, respectively. After an initial 3-day adaptation period, all animals in all groups received continuous isocaloric (175 kcal/kg/day) intragastric tube feeding until postburn day (PBD) 14. At PBD 14, although BCAA-supplemented groups showed very high plasma levels of BCAA (IV: 169%; V: 306%; VI: 770% of normal), no BCAA group showed evidence of any beneficial effect in various nutritional parameters when compared with the corresponding whey protein group with isonitrogenous intake. Cumulative nitrogen balance and mortality during 14 days were significantly worse in BCAA groups IV and VI than in control groups I and III, respectively. It is concluded that BCAA supplementation to enteral diets has no beneficial effect for postburn nutritional management following severe burn injury. It is further suggested that when nitrogen intake is too low or very high, BCAA supplementation may have an adverse effect.

Immunomodulators for the prevention of infections in burned guinea pigs

Patients with thermal injury suffer a high incidence of infectious complications secondary to impaired host resistance. Nonspecific immunostimulatory agents are being tested increasingly for their ability to correct the postburn immunosuppression. By means of a burned guinea pig model, three such drugs--indomethacin, cyclophosphamide, and cimetidine--were tested for their ability to correct immunosuppression and prevent lethal infectious complications. The burned animals were challenged with Pseudomonas aeruginosa 1244 on the third postburn day. Neither indomethacin nor cimetidine altered the animals' clinical course. However cyclophosphamide, at a dosage of 2 mg/kg body weight/day, improved survival from 30% to 57% and prolonged mean survival time from 5.72 to 7.77 days. Cyclophosphamide, at a dosage of 15 mg/kg body weight/day, decreased mean survival to 3.63 days and percent survival to 0. These data show that treatment with cyclophosphamide could be beneficial in severe burn injury patients, but further work is necessary due to the dose-dependent nature of the drug.

High protein diets are associated with increased bacterial translocation in septic guinea pigs

During sepsis, body protein stores are decreased due to an increase in protein catabolism. The utilization of nutritional support with high-protein diets has been used as a solution to the problem of sepsis-induced protein loss. Work from our laboratory, however, has shown that diets low in protein (5% of total calories) improve survival in septic animals as compared to high protein (20%) diets. The present study investigated the relationship between low-protein diets and improved survival by determining whether septic animals receiving high-protein diets have increased bacterial translocation. Sepsis was induced in guinea pigs by the implantation of an osmotic minipump into the peritoneal cavity containing an equal mixture of Escherichia coli (10(8)) and Staphylococcus aureus (10(8)) or saline. On Day 3 postlaparotomy, the animals were randomized to one of four groups. The groups consisted of septic and nonseptic animals that received a diet with 5 or 20% of total calories as protein. Following 4 days of diet all animals received an instillation of 14C labeled E. coli (10(10)). Four hours later the animals were sacrificed and blood, mesenteric lymph nodes, spleen, lungs, and liver were removed for determination of radionuclide counts. Results indicated that the septic animals that received the high protein diet had more bacterial translocation, as indexed by higher radionuclide counts in the MLN, liver, lung and blood. These findings suggest that a low protein, enterally fed diet may improve survival in septic patients by decreasing the incidence of bacterial translocation.

Immunoregulation of transfusion-induced immunosuppression with inhibitors of the arachidonic acid metabolism

To further define the role of arachidonic acid (AA) metabolites in transfusion-induced immunosuppression (TII), the effects of pharmacological manipulation of AA metabolism were examined in a rodent model. If the prostaglandins of the E series are mediators of TII, as has been recently hypothesized, then inhibition of cyclooxygenase (indomethacin) should abrogate whereas inhibition of lipoxygenase (nordihydroguaiaretic acid [NDGA]), or thromboxane synthetase (4-63557A) could potentiate the transfusion effect. Lewis rats received donor-specific transfusions from Buffalo rats in conjunction with one of the above inhibitors. Two weeks later they received intraabdominal Buffalo heart allografts or were used for one-way mixed lymphocyte reactions. Cyclooxygenase inhibition partially abrogated TII with shortened cardiac allograft survival. Lipoxygenase inhibition augmented TII, with depression of MLR and prolongation of allograft survival. Thromboxane synthetase inhibition had no effect. These results indicate that AA metabolites play a role in TII, and that immunoregulation via pharmacological manipulation of AA metabolism is possible.

Bone marrow and splenocyte coculture-generated cells enhance allograft survival

BACKGROUND

Protocols that incorporate donor-specific cell infusions using bone marrow, spleen, or blood transfusion continue to enhance allograft survival and often lead to tolerance in experimental models. Clinical benefits from these modalities have not been as striking, leading to ongoing study in this field. We have explored culture techniques for the in vitro selection and development of cellular effectors capable of enhancing allograft survival.

METHODS

Rat bone marrow or spleen cells cultured under a variety of conditions were screened for suppressor function. Bone marrow cells, nonadherent to plastic, cultured for 7 days with granulocyte-macrophage colony-stimulating factor, lipopolysaccharide, and with or without splenocytes were found to contain predominantly myeloid lineage cells and had the ability to suppress phytohemagglutinin or mixed lymphocyte reaction-induced splenocyte proliferation. Standard donor-specific peripheral blood transfusion was compared with cultured donor-specific bone marrow cells, splenocytes, or marrow cells cultured with splenocytes (cocultured) administered intravenously at 1 x 10(7) cells/kg the day before an ACI to Lewis heterotopic heart transplant. Cyclosporine was administered at 10 mg/kg on day -1 and 2.5 mg/kg on days 0-6 relative to transplantation.

RESULTS

Mean allograft survival in cyclosporine-treated animals was 8.5 days without and 16.6 days with a donor-specific blood transfusion. Cocultured cells extended allograft survival (39.5 days), whereas bone marrow or splenocytes cultured alone did not. With Percoll gradient separation, two predominant culture subfractions, one with potent suppressor function and another with stimulator function, were identified. Flow cytometric analysis showed mixed populations enriched for macrophages but also including dendritic cells in both subfractions. The suppressive fraction extended allograft survival to 20.8 days and the stimulatory fraction was less effective, yet remixing of both fractions regained the full allograft survival advantage.

CONCLUSIONS

In this model, the coculture of bone marrow cells and splenocytes with granulocyte-macrophage colony-stimulating factor and lipopolysaccharide produced functionally divergent subpopulations that synergistically enhanced allograft survival. The development of cellular effectors with enhanced ability to prolong allograft survival using in vitro culture techniques is possible, and provides a new therapeutic option in the use of cell infusion-based therapies.

A strategy for generating consistent long-term donor-specific tolerance to solid organ allografts

Current triple drug immunosuppression while effective, increases the risk of opportunistic infection and lymphoproliferative disorders. An alternative strategy would be the generation of donor-specific tolerance with short-term treatment. The use of donor-specific transfusions (DST) with a single brief course of cyclosporine (CsA) and rapamycin (Rapa) has produced promising results in animal models, but falls short of uniform tolerance. It was hypothesized that a DST/CsA/Rapa protocol administered in the perioperative period and redosed at one month might improve on this success in the ACI to Lewis rat heterotopic cardiac transplant model. Recipients received no treatment (group 1), a 1 ml DST intravenously (i.v.) with CsA 10 mg/kg subcutaneously (s.c.) at D-1 and CsA 2.5 mg/kg DO6D+13 (group 2), DST/CsA as dosed above with intraperitoneally (i.p.) Rapa 1 mg/kg D+36D+7 (group 3), DST/CsA/Rapa as above with all components redosed at one month (group 4), DST/CsA/Rapa with only CsA and Rapa repeated (group 5), and DST/CsA/Rapa with CsA redosed and Rapa continued indefinitely (group 6). Comparison of permanent survival (longer than 200 days) between protocols revealed groups 4-6 were significantly greater than control groups 1-3. Donor specificity was verified in group 6, where three permanent survivors received a second cardiac allograft from a Buffalo rat donor and rejected these grafts almost as quickly as untreated strain pair matched controls 21 +/- 1 days vs 30.3 +/- 5 days. Animals from group 6 displayed a greatly reduced mixed lymphocyte response to ACI cells but not to third-party cells. The percentage of T cells producing cytokines was reduced and shifted toward Th-2 type cytokines (IL-4). Thus, a repeated cycle of this brief DST/CsA/Rapa treatment appears to generate consistent permanent graft survival (up to 91%) that exceeds previously studied tolerance inducation protocols and is donor specific.

Fungal translocation is associated with increased mortality after thermal injury in guinea pigs

Thermal injury increases the rate of translocation of Candida albicans in guinea pigs, but early enteral feeding can significantly decrease this rate. We studied the combined effects of C. albicans translocation and early feeding on outcome of thermal injury in guinea pigs. Eighty guinea pigs were subjected to a flame burn covering 50% total body surface area. One hour before burn injury, half of the animals underwent gavage with 3 x 10(10) viable C. albicans, a dosage that in previous studies was associated with greater than 90% incidence of yeast translocation to the mesenteric lymph nodes. The other half underwent gavage with an equal volume of saline. After injury, half of each group were randomly selected to receive guinea pig feed ad libitum and the other half were starved for 72 hours. All were allowed access to water ad libitum. Mortality rate was recorded at 3 3 days. The group that underwent gavage with C. albicans and subsequent starvation after burn injury had a significantly higher mortality rate than had any of the other groups. We conclude that induced translocation of C. albicans in guinea pigs increases mortality after burn injury. Moreover, early enteral feeding has a protective effect, presumably by decreasing translocation rates has been shown in previous studies.

Studies on segmental pancreatic autotransplants in dogs

Success with segmental pancreas transplants has been impaired by immunologic and technical considerations. Experiments were performed with autotransplants to avoid immunologic problems, allowing concentration on surgical techniques. Survival of splenic lobe pancreas autotransplants in pancreatectomized dogs was extended with relocation of the graft from the groin to the abdominal cavity and distal arteriovenous fistula to increase graft flow. Fibrosis of the graft occurred regardless of the method of duct treatment, latex (Neoprene) or Silastic injection or free intraperitoneal drainage. Hormonal responses in normoglycemic animals showed normal insulin levels (6 +/- 0.8 microU/mL) as compared with controls (5.4 +/- 0.9 microU/mL), while peak levels during arginine stimulation were higher in dogs with autotransplants (39.7 +/- 20 microU/mL) than in controls (15.1 +/- 1.9 microU/mL. Pancreatic polypeptide basal levels in animals with transplants were 42 +/- 2.2 pg/mL as compared with 256 +/- 28 pg/mL in controls, with no response to bombesin or protein meal stimulation. In this model, splenic lobe was capable of maintaining normoglycemia with avoidance of ketogenic amino acid patterns. Continuous fibrosis was the biggest threat to islet survival.