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At least 19 recordsLinked to original sources

PubMed2005

Grafts in dermatologic surgery: review and update on full- and split-thickness skin grafts, free cartilage grafts, and composite grafts.

BACKGROUND: Skin grafting has evolved in the past centuries to encompass numerous well-established reconstruction techniques that are uniquely able to restore structure, function, and cosmesis to a variety of surgical wounds. OBJECTIVE: To provide a detailed overview of the general principles of skin grafting geared for the dermatologist and the dermatologic surgeon. METHODS: Comprehensive review of the literature. RESULTS: A summary of the different applications and techniques of full- and split-thickness skin grafts, free cartilage grafts, and composite grafts is presented. Indications, advantages, disadvantages, techniques, and complications are discussed in depth. CONCLUSION: Skin grafting is a dynamic and versatile method of cutaneous reconstruction that can be accomplished successfully with a thorough understanding of the principles and techniques of grafting.

Ear Cartilage↗

PubMed1997

[Evaluation of the graft flow reserve after coronary artery bypass grafting by stress 201T1 myocardial SPECT: comparison between arterial grafts and venous grafts].

We performed stress 201T1 myocardial SPECT to evaluate ischemia and perfusion reserve after coronary artery bypass grafting (CABG). A total of 103 patients was performed stress 201T1 myocardial SPECT one month after CABG. Each patient's myocardium was divided into 9 segments and visually evaluated using five grade scoring system (0 = defect, 1 = severe decrease, 2 = moderate decrease, 3 = mild decrease, 4 = normal uptake). Eleven of 133 (8.27%) segments covered by patent venous grafts showed reversible 201T1 defect, however, 36 of 117 (30.8%) segments which covered by patent arterial grafts showed reversible 201T1 defect. This finding was observed more significantly in arterial grafts than in venous grafts (p < 0.001). These finding suggests that arterial grafts have lower flow capacity than venous grafts at peak exercise.

Aged↗

PubMed1985

Effect of skin graft preparation and graft survival on the secondary contraction of full-thickness skin grafts in dogs.

The effects of 4 skin grafting techniques and graft survival on the secondary contraction of full-thickness skin grafts were evaluated. A total of 48 skin grafts were done on 12 dogs, with 2 skin grafts placed on both sides of the thorax of each dog. The grafting techniques included the sheet graft, sheet graft with continuous low-level suction provided by a butterfly catheter and evacuated glass tube, pie-crust graft, and nonexpanded mesh graft. Graft viability was assessed by visual inspection 10 days after surgical operation. Thirty skin grafts (64%) had a viability of 90% or greater. The final area of these grafts ranged from 73% to 119% of the original area. The secondary graft contraction followed a similar pattern for all graft types. During the first 10 days after surgical operation, the grafts contracted to 83% of their original area. Enlargement of the grafts began between 10 and 21 days after surgical operation. By 12 weeks, the grafts had attained a mean value of 96% of the original area. A significant difference in final area was not observed among graft types. Grafts with a high percentage of viability generally contracted less than those with larger areas of necrosis, but statistical relationship between viability and degree of contraction could not be proven. The results of the present study indicate that full-thickness skin grafts may be successfully done in dogs and that the grafts can be expected to undergo minimal postoperative contraction when graft survival is nearly complete.

Animals↗

PubMed2004

Single versus bilateral internal thoracic artery grafts with concomitant saphenous vein grafts for multivessel coronary artery bypass grafting: effects on mortality and event-free survival.

BACKGROUND: The issue of superiority of single internal thoracic artery grafting versus bilateral internal thoracic artery grafting remains unresolved. The aim of this study was to compare the long-term outcome of single and bilateral internal thoracic artery grafting with concomitant saphenous vein grafting for multivessel coronary artery bypass grafting. METHODS: Between March 1985 and April 1995, 6650 patients underwent primary isolated coronary artery bypass grafting with internal thoracic artery grafts, including 4382 patients with multivessel bypass grafting requiring at least 3 grafts. Outcomes of patients undergoing single internal thoracic artery plus saphenous vein grafting (n = 2547) and bilateral internal thoracic artery plus saphenous vein grafting (n = 1835) were obtained at a mean follow-up of 11 +/- 3 years. RESULTS: Patients with bilateral internal thoracic artery grafting were younger, were mostly male, and had less diabetes, hypertension, unstable angina, and recent myocardial infarction than patients undergoing single internal thoracic artery grafting. Thirty-day mortality was 2.3% for the group undergoing single internal thoracic artery grafting versus 1.2% for those undergoing bilateral internal thoracic artery grafting (P =.007). Survival probability at 10 years was 88% for the single-graft group compared with 93% for the bilateral-graft group (P <.001). Multivariate analysis with propensity scoring showed that bilateral internal thoracic artery grafting decreased the risk of death (hazard ratio, 0.74; 95% confidence interval, 0.60-0.90), myocardial infarction (hazard ratio, 0.79; 95% confidence interval, 0.67-0.93), and coronary reoperation (hazard ratio, 0.41; 95% confidence interval, 0.21-0.80) throughout the follow-up period. Other significant predictors of death were diabetes, prior myocardial infarction, need for intra-aortic balloon pump, chronic heart failure, and peripheral vascular disease. CONCLUSION: Patients undergoing bilateral internal thoracic plus saphenous vein grafting appear to have a significantly better long-term clinical outcome than patients undergoing single internal thoracic artery plus saphenous vein grafting for multivessel coronary artery bypass grafting.

Coronary Artery Bypass↗

PubMed2000

Long-term outcome after treatment of aortic graft infection with staged extra-anatomic bypass grafting and aortic graft removal.

OBJECTIVE: The purpose of this study was to determine long-term outcome in patients with infected prosthetic aortic grafts who were treated with extra-anatomic bypass grafting and aortic graft removal. METHODS: Between January 1989 and July 1999, 36 patients were treated for aortic graft infection with extra-anatomic bypass grafting and aortic graft removal. Extra-anatomic bypass graft types were axillofemoral femoral (5), axillofemoral (26; bilateral in 20), axillopopliteal (3; bilateral in 1) and axillofemoral/axillopopliteal (2). The mean follow-up was 32.3 +/- 4. 8 months. RESULTS: Four patients (11%) died in the postoperative period, and two patients died during follow-up as a direct consequence of extra-anatomic bypass grafting and aortic graft removal (one died 7 months after extra-anatomic bypass graft failure, one died 36 months after aortic stump disruption). One additional patient died 72 months after failure of a subsequent aortic reconstruction, so that the overall treatment-related mortality was 19%, whereas overall survival by means of life table analysis was 56% at 5 years. No amputations were required in the postoperative period, but four patients (11%) required amputation during follow-up. Twelve patients (35%) had extra-anatomic bypass graft failure during follow-up, and six patients underwent secondary aortic reconstruction (thoracobifemoral [2], iliofemoral [2], femorofemoral [2]). However, with the exclusion of patients undergoing axillopopliteal grafts (primary patency 0% at 7 months), only seven patients (25%) had extra-anatomic bypass graft failure, and only two patients required amputation (one after extra-anatomic bypass graft removal for infection, one after failure of a secondary aortic reconstruction). Furthermore, primary and secondary patency rates by means of life table analysis were 75% and 100% at 41 months for axillofemoral femoral grafts and 64% and 100% at 60 months for axillofemoral grafts. Only one patient required extra-anatomic bypass graft removal for recurrent infection, and only one late aortic stump disruption occurred. CONCLUSIONS: Staged extra-anatomic bypass grafting (with axillofemoral bypass graft) and aortic graft removal for treatment of aortic graft infection are associated with acceptable early and long-term outcomes and should remain a primary approach in selected patients with this grave problem.

Aged↗

PubMedDate not supplied

Survival and wound contraction of full-thickness skin grafts are associated with the degree of tissue edema of the graft bed in immediate excision and early wound excision and grafting in a rabbit model.

The objective of this study was to evaluate the survival of skin grafts on graft beds of immediate excision and early wound excision at various time periods after burns and to establish the appropriate timing of burn excision and grafting in a rabbit model. Eight groups of male Japanese white rabbits (n = 5 per group) were established. Animals of all groups were given a 5 x 10-cm full-thickness burn on their shaved back and received the autografting 3, 6, 12, 18, 24, 48, and 72 hours and 5 days after receiving burns, respectively. Weekly skin-graft evaluation was performed for 5 weeks after grafting by measurement of the secondary skin graft contracture (in size) and the survival area of grafts, with use of computerized planimetry. In addition, relative quantitative analysis of exudation on the burned wound was evaluated. Our results indicated that the exudate-related graft loss and graft contracture varied according to the timing of wound excision. The wound contractures of the grafts were maximal in both the 18-hour and 24-hour groups at 2, 3, 4, and 5 weeks after grafting. The 18-hour and 24-hour groups exhibited significantly greater graft loss than the 72-hour and 5-day groups (P < .05). An apparent increase in the amount of exudation on the graft bed was shown in the 18- and 24-hour groups vs the other groups (P < .05). A reverse correlation was detected between the survival area of the skin graft and the degree of exudation of the graft bed. In conclusion, the survival area and secondary contraction of skin grafts are associated with the degree of tissue edema of the graft bed in immediate excision and early excision in the rabbit model. The adverse affect of edema leakage on the graft bed for skin graft survival was shown. We believe that immediate excision or early wound excision and grafting performed within 12 hours after burn or 48 hours later should be considered in the rabbit model.

Animals↗

PubMed1996

Local application of vancomycin for prophylaxis of graft infection: release of vancomycin from antibiotic-bonded Dacron grafts, toxicity in endothelial cell culture, and efficacy against graft infection in an animal model.

Methicillin-resistant strains of Staphylococcus epidermidis cause an increasing number of prosthetic infections. This prompted us to test the uptake of vancomycin in various graft materials in vitro, its influence on graft healing, and its efficacy against graft infection in pigs. Incubation of six different Dacron graft materials in a vancomycin solution (20 gm/L) was performed. Grafts were then placed in plasma, and samples were taken over 72 hours to determine vancomycin levels. Release of vancomycin ranged from 775 micrograms/cm2 to 3691 micrograms/cm2 after 1 hour of incubation. Gelatin-covered grafts increased release of vancomycin fourfold when incubation time was extended to 24 hours: uncovered grafts or the collagen-covered graft did not. Graft healing was not complicated when a vancomycin-bonded, gelatin-impregnated Dacron graft was implanted to replace the common femoral artery in pigs. Four weeks after implantation, histologic examination revealed normal development of neointima and perigraft scar tissue in the vancomycin-treated (n = 4) and untreated (n = 5) grafts. To test the efficacy of local vancomycin against graft infection, grafts were implanted in the groin of pigs and contaminated with 2 x 10(7) colony-forming units of Staphylococcus aureus. Four weeks after implantation, all grafts were infected in the untreated group (n = 6), with abscess, nonincorporated graft, and detection of S. aureus from the graft. In the treatment group (n = 6) vancomycin was added to the contaminated grafts. As a carrier for the vancomycin, we used a resorbable gelatin-glycerol foam. All grafts healed without infection. The difference between the treated and untreated groups is statistically significant (p < 0.05). We conclude that it may be effective to prevent graft infection with local application of vancomycin if an in situ replacement of infected graft (infected by gram-positive bacteria) is necessary or if there is a high risk of infection by methicillin-resistant- staphylococci.

Animals↗

PubMed1992

Vasomotor response to ergometrine and nitrates of saphenous vein grafts, internal mammary artery grafts, and grafted coronary arteries late after bypass surgery.

BACKGROUND: In vitro studies have shown that the vasomotor response of internal mammary artery to vasoactive agents differs from that of saphenous vein. METHODS AND RESULTS: To assess whether the response in vivo to methylergometrine and to nitrates differs in saphenous vein grafts, internal mammary artery grafts, and coronary arteries, 25 patients were studied more than 6 months (range, 6-96 months) after surgery. Angiograms of saphenous vein grafts (n = 11) or mammary artery grafts (n = 14) were obtained in basal conditions, after intravenous infusion of 0.4 mg methylergometrine, and after intragraft infusion of 1 mg isosorbide dinitrate. Computerized quantitative angiography was used to assess the changes in luminal diameter of the bypass graft and of the grafted coronary artery (n = 11). Methylergometrine reduced the diameter of saphenous vein grafts by 6.9 +/- 7.4%, from 3.26 +/- 0.71 to 3.05 +/- 0.76 mm (p < 0.01), and that of grafted coronary arteries by 9.3 +/- 7.2% (NS compared with saphenous vein grafts), from 2.08 +/- 0.49 to 1.89 +/- 0.49 mm (p < 0.005). The diameter of internal mammary artery grafts did not change significantly, from 3.27 +/- 0.42 to 3.25 +/- 0.44 mm (-0.3 +/- 5.1%, p < 0.02 compared with saphenous vein grafts and p < 0.002 compared with coronary arteries). After isosorbide dinitrate, the diameter of both grafted coronary arteries and mammary artery grafts increased significantly (respectively to 2.46 +/- 0.62 mm and 3.44 +/- 0.43 mm), the vasodilatation being greater (p < 0.002) in coronary arteries (+17.8 +/- 9.8% in proportion to basal diameter, p < 0.001) than in mammary grafts (+5.5 +/- 3.3%, p < 0.001). The diameter of saphenous vein grafts returned to control values (3.28 +/- 0.70 mm, NS compared with basal); the changes in luminal diameter after nitrates (+0.7 +/- 3.1%, NS) were significantly smaller than for mammary artery grafts (p < 0.01) and for grafted coronary arteries (p < 0.001). CONCLUSIONS: Unlike internal mammary artery grafts, saphenous vein grafts constrict in response to methylergometrine and do not dilate in response to nitrates. These differences in vasomotor response could reflect heterogeneity in the sensitivity of vascular smooth muscle to these agents or differences in the basal level of vasomotor tone.

Cardiac Catheterization↗

PubMed2001

Comparisons of intraosseous graft healing between the doubled flexor tendon graft and the bone-patellar tendon-bone graft in anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to compare intraosseous graft healing between the doubled flexor tendon (FT) graft and the bone-patellar tendon-bone (BPTB) graft in anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Randomized trial. METHODS: A biomechanical and histologic study was conducted with 24 adult beagle dogs. Bilateral ACL reconstructions were performed in each animal. Autogenous doubled FT and BPTB grafts were used for the left and right knees, respectively. Each end of the 2 grafts was tethered with a polyester suture to a screw post with a washer. The animals were then allowed unrestricted activities in their cages. Eight animals were killed at 3, 6, and 12 weeks, respectively. RESULTS: Histologically, the FT graft was anchored to the tunnel wall with newly formed collagen fibers resembling Sharpey's fibers by 12 weeks. These fibers were more abundant in the anterior (ventral) gap than in the posterior (dorsal) gap. In the BPTB graft, the bone plug was anchored with newly formed bone at 3 weeks, although osteocytes in the plug trabeculae were necrotic for 12 weeks. Degeneration of the tendon-bone junction in the plug progressed at 6 weeks. Tensile testing showed that the weakest site was different not only between the 2 grafts but also between the observation periods. In the FT graft, the weakest site was the graft-wall interface at 3 weeks and the intraosseously grafted tendon at 6 weeks. In the BPTB graft, the weakest site was the graft-wall interface at 3 weeks and the proximal site in the bone plug at 6 weeks. The ultimate failure load of the FT graft was significantly inferior (45.8%) to that of the BPTB graft at 3 weeks (P =.021). At 6 weeks, the load of the FT graft was 85% that of the BPTB graft without a significant difference (P =.395). CONCLUSIONS: As to the clinical relevance, the fixation device chosen for soft-tissue fixation appears to be more important than comparing it to the BPTB graft, although this has yet to be conclusively proven.

Animals↗

PubMed2001

Early graft function after pediatric liver transplantation: comparison between in situ split liver grafts and living-related liver grafts.

BACKGROUND: The systematic application of living-related and cadaveric, in situ split-liver transplantation has helped to alleviate the critical shortage of suitable-sized, pediatric donors. Undoubtedly, both techniques are beneficial and advantageous; however, the superiority of either graft source has not been demonstrated directly. Because of the potential living-donor risks, we reserve the living donor as the last graft option for pediatric recipients awaiting liver transplantation. Inasmuch as no direct comparison between these two graft types has been performed, we sought to perform a comparative analysis of the functional outcomes of left lateral segmental grafts procured from these donor sources to determine whether differences do exist. METHODS: A retrospective analysis of all liver transplants performed at a single institution between February 1984 and January 1999 was undertaken. Only pediatric (<18 years) recipients of left lateral segmental grafts procured from either living-related (LRD) or cadaveric, in situ split-liver (SLD) donors were included. A detailed analysis of preoperative, intraoperative, and postoperative variables was undertaken. Survival was estimated using the Kaplan-Meier method, and comparison of variables between groups was undertaken using the t test of Wilcoxon rank sum test. RESULTS: There were no significant differences in the preoperative variables between the 39 recipients of SLD grafts and 34 recipients of LRD grafts. The donors did differ significantly in mean age, ABO blood group matching, and preoperative liver function testing. Postoperative liver function testing revealed significant early differences in aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, prothrombin time, and alkaline phosphatase, with grafts from LRD performing better than those from SLD. SLD grafts also had significantly longer ischemia times and a higher incidence of graft loss owing to primary nonfunction and technical complications (9 vs. 2, P<0.05). However, six of these graft losses in the SLD group were because of technical or immunologic causes, which, theoretically, should not differ between the two groups. Furthermore, these graft losses did not negatively impact early patient survival as most patients were successfully rescued with retransplantation (30-day actuarial survival, 97.1% SLD vs. 94.1% LRD, P=0.745). In the surviving grafts, the early differences in liver function variables normalized. CONCLUSIONS: Inherent differences in both donor sources exist and account for differences seen in preoperative and intraoperative variables. Segmental grafts from LRD clearly performed better in the first week after transplantation as demonstrated by lower liver function variables and less graft loss to primary nonfunction. However, the intermediate function (7-30 days) of both grafts did not differ, and the early graft losses did not translate into patient death. Although minimal living-donor morbidity was seen in this series, the use of this donor type still carries a finite risk. We therefore will continue to use SLD as the primary graft source for pediatric patients awaiting liver transplantation.

Adult↗

PubMed1998

Angiographic predictors of graft patency and disease progression after coronary artery bypass grafting with arterial and venous grafts.

BACKGROUND: There are few data about angiographic determinants of functional graft patency and native artery disease progression after coronary artery bypass grafting operation with arterial grafts compared with venous grafts. METHODS: Baseline and follow-up coronary angiograms at a mean of 2 years after operation in 91 patients with 194 arterial and 204 venous graft anastomoses were analyzed. RESULTS: Ninety-two percent of the arterial and 87% of the venous graft anastomoses were patent at follow-up angiography (p = 0.05, odds ratio = 2.63). Unlike that of arterial grafts, the patency rate of venous graft anastomoses correlated negatively with decreasing severity of the bypassed lesion. In contrast to venous grafts, in which angiographic graft function was basically dichotomous (fully patent or occluded), compromised flow of the arterial graft anastomoses was registered in 12%. Progression of the disease was more common in segments bypassed with venous grafts than with arterial grafts (p = 0.001, odds ratio = 2.03). CONCLUSIONS: Angiographic determinants of functional graft patency and progression of occlusive changes in the bypassed artery segments are different for arterial and venous grafts.

Coronary Angiography↗

PubMed1999

Autogenous artery grafts in hypertensive (SHR) rats do not have increased smooth muscle cell hyperplasia in the graft neointima, compared with grafts in normotensive rats.

Vein-to-artery graft surgery is used widely to by-pass arterial stenoses, but such grafts can fail over a prolonged period as a result of excessive neointimal hyperplasia causing thrombosis and graft occlusion. It has been suggested that neointimal hyperplasia, in vein grafts, is a result of the vessel wall adapting to the higher intraluminal pressure of the arterial circulation, compared with the venous circulation. Autologous artery grafts have been used to bypass arterial stenoses. Initially it was assumed that donor artery segments would not develop neointimal hyperplasia as they are already adapted to the arterial circulation but this is not so. In this study we postulated that surgical or postsurgical trauma was the cause of neointimal hyperplasia in autologous artery-to-artery grafts. In addition, as artery grafts are pre-adapted to the arterial circulation, autologous artery-to-artery grafts in hypertensive rats should develop similar levels of neointimal hyperplasia as seen in normotensive rats. Artery-to-artery grafts were placed in a series of 20 spontaneously hypertensive rats (SHR). In a separate series of sham grafting experiments the effects of anoxia and clamp trauma were assessed in SHR and WKy normotensive control rats. Finally, clamping, anoxia and anastomosis trauma were assessed in a similar series of rats. In the artery-to-artery graft series there was no difference in neointimal thickness between the SHR and that previously reported for normotensive rats. Minimal neointimal hyperplasia was demonstrated in the sham grafted series of rats and only slightly more in the single anastomosis series. It was only in the full grafting procedure that considerable neointimal hyperplasia developed. These data demonstrate that neointimal hyperplasia in artery-to-artery grafts is not exacerbated by the hypertension. In addition, trauma appears to be the initiator of neointimal hyperplasia and the extent of trauma correlates with the degree of neointimal hyperplasia.

Animals↗

PubMed1999

Worse clinical outcome but similar graft patency in women versus men one year after coronary artery bypass graft surgery owing to an excess of exposed risk factors in women. CABADAS. Research Group of the Interuniversity Cardiology Institute of The Netherlands. Coronary Artery Bypass graft occlusion by Aspirin, Dipyridamole and Acenocoumarol/phenoprocoumon Study.

OBJECTIVES: This retrospective study sought to assess differences in graft patency and clinical outcome between women and men after coronary artery bypass graft surgery (CABG). BACKGROUND: A less favorable clinical outcome has been reported in women as compared with men. Its relation to graft patency has not been studied. METHODS: We analyzed one-year follow-up data of 912 patients (120 women) who entered a randomized clinical drug trial. All patients received vein grafts; in 494 patients (56 women) internal mammary artery (IMA) grafts were also used. Graft patency was assessed by coronary angiography at one year. Primary clinical end points were myocardial infarction, revascularization procedures and death; secondary clinical end points included recurrent angina, heart failure and arrhythmias. RESULTS: Occlusion rates of vein grafts were 16.7% in women and 12.4% in men (odds ratio [OR] 1.62, 95% confidence interval [CI] 0.88 to 3.00, p = 0.12); occlusion rates of IMA grafts were 3.4% and 5.7% in women and men, respectively (OR 0.56, 95% CI 0.08 to 3.96, p = 0.56). Primary clinical end points were observed in 16.7% of women and 9.2% of men (OR 1.97, 95% CI 1.10 to 3.34, p = 0.022), and any clinical end point in 41.7% of women and 25.8% of men (OR 2.06, 95% CI 1.39 to 3.04, p = 0.0004). Myocardial infarction (15% vs. 7.6%, OR 2.15, 95% CI 1.24 to 3.75, p = 0.013) and recurrent angina (26.7% vs. 15.4%, OR 2.00, 95% CI 1.28 to 3.11, p = 0.004) occurred most frequently. Multivariate regression analysis did not identify gender as an independent risk factor for graft occlusion or the clinical end points. Graft occlusion was an independent predictor of the composite primary clinical end point (OR 2.75, 95% CI 1.59 to 4.75, p = 0.0003) and each of the secondary clinical end points. The observed differences were due to an imbalance of risk factors at baseline and to surgical and graft characteristics. CONCLUSIONS: One-year occlusion rates of vein and IMA grafts were comparable in women and men. Clinical outcome was related to graft patency and was less favorable in women owing to their uneven distribution of risk factors among both groups.

Aged↗

PubMed1997

Combination therapy with cyclosporine and interleukin-4 or interleukin-10 prolongs survival of synergeneic pancreatic islet grafts in nonobese diabetic mice: islet graft survival does not correlate with mRNA levels of type 1 or type 2 cytokines, or transforming growth factor-beta in the islet grafts.

BACKGROUND: The recurrent autoimmune response to syngeneic pancreatic islet grafts transplanted into nonobese diabetic (NOD) mice is cell-mediated and relatively resistant to cyclosporine (CsA) therapy. Therefore, we asked whether interleukin (IL)-4 and IL-10, cytokines that inhibit cell-mediated immunity, might improve the therapeutic effect of CsA. METHODS: We compared the survival of syngeneic islet grafts transplanted into diabetic NOD mice treated with IL-4, IL-10, and CsA, administered as single agents and in combinations. Additionally, we measured mRNA levels of type 1 cytokines (interferon-gamma [IFN-gamma], IL-2, and IL-12), type 2 cytokines (IL-4 and IL-10), and transforming growth factor-beta (TGF-beta) to determine whether graft rejection or survival might correlate with expression of these cytokines in the grafts. RESULTS: CsA (20 mg/kg/day) significantly prolonged islet graft survival (median: 20 days vs. 10 days for vehicle-treated mice). Neither IL-4 (2.5 microg, twice daily), nor IL-10 (10 microg, twice daily) significantly prolonged islet graft survival. By contrast, combination therapy with CsA and IL-10 significantly prolonged islet graft survival (median: 34 days) compared with vehicle-treated mice (median: 10 days), and combination therapy with CsA and IL-4 significantly prolonged islet graft survival (median: 59 days) compared with both vehicle-treated mice (median: 10 days) and mice treated with CsA alone (median: 20 days). Islet grafts from normoglycemic mice treated with CsA plus IL-10, and with CsA plus IL-4, were surrounded but not infiltrated by mononuclear leukocytes and beta cells were intact, whereas islet grafts from mice treated with vehicle, IL-4, IL-10, and CsA (as single agents) were infiltrated by mononuclear leukocytes and fewer beta cells were detected. Polymerase chain reaction analysis of cytokine mRNA expression in islet grafts at 8-12 days after transplantation revealed that CsA decreased mRNA levels of type 1 cytokines (IFN-gamma and IL-12p40), whereas CsA plus IL-10 did not, and CsA plus IL-4 increased mRNA levels of IFN-gamma, IL-12p40, and TGF-beta. CONCLUSIONS: These results demonstrate that IL-4, and to a lesser extent IL-10, improves the ability of CsA to prevent autoimmune destruction of beta cells in syngeneic islets transplanted into diabetic NOD mice; however, there is no simple correlation between the protective effects of the different treatment regimens (CsA, CsA plus IL-4, and CsA plus IL-10) and mRNA levels of type 1 cytokines (IFN-gamma, IL-2, and IL-12), type 2 cytokines (IL-4 and IL-10), or TGF-beta in the islet grafts.

Animals↗

PubMed2002

[Expanding the grafts pool for pediatric liver transplantation with segmental grafts from living donor and cadaveric reduced size or split grafts].

AIM: To compare short and long-term results of pediatric liver transplantation (LT), utilizing segmental grafts from living donors (LD) vs. cadaveric (CAD) reduced size or split grafts. METHODS: A retrospective analysis of a single center experience (1993-2000), comparing the surgical outcome, the graft function and the survival rates between these groups. RESULTS: Of 195 LTs in pediatric recipients (age < 18), 48 (25%) were with LD grafts and 47 (24%) with CAD grafts (reduced size, n = 27, or split, n = 20). The mean age and weight of the LD recipients were 1.8 +/- 3 yrs and 9.0 +/- 8.1 kg vs. 3.5 +/- 4 yrs. and 15.2 +/- 14.5 kg in the CAD group. The distribution of etiologies was comparable (EHBA, 54% vs. 49%; inborn errors in metabolism, 12.5% vs. 12%; acute idiopathic hepatic failure, 12.5% vs. 14.2%). The severity of pretransplant disease and the fraction of acute hepatic failure cases were also comparable, although less LD grafts were used for urgent re-transplantation due to primary non-function or vascular complications (1 case in the LD group vs. 6 in the CAD group). The median warm ischemia time was similar (43 min; range, 28-87 min vs. 45 min; range 12-82 min), but the median cold ischemia time was significantly different (60 min; range 43-298 in LD vs. 637 min; range, 342-1102 in CAD grafts). Both patient and graft survival in 3 months, 1 and 5 years were significantly superior in the LD group (patient survival, 97%, 91% and 89% vs. 82%, 70% and 62%, p < 0.001; graft survival, 92%, 89% and 77% vs. 66%, 59% and 52%, p < 0.005). The incidence of vascular complications (hepatic artery or portal vein thrombosis) and biliary complications (leak of stricture) was comparable (vascular, 10% vs. 7%, biliary, 16% vs. 9%). The incidence of poor early graft function (6% vs. 21%) and primary non-function (2% vs. 18%) was significantly lower in the LD group. CONCLUSION: Although presenting similar surgical complexity, the outcome of segmental grafts from LD is better than of reduced size or split cadaveric grafts.

Adolescent↗

PubMed2004

Graft healing in a bone tunnel: bone-attached graft with screw fixation versus bone-free graft with extra-articular suture fixation.

The purpose of this study was to clarify differences in tendon graft-to-bone tunnel healing between bone-attached tendon grafts with interference-screw fixation and bone-free tendon grafts with extra-articular suture fixation. In 42 Japanese White rabbits, anterior half replacement of the medial collateral ligament was performed using half of the ipsilateral patellar tendon. At the femoral attachment, the bone-plug-attached graft was fixed with an interference screw (group A). The bone-plug-free graft was fixed by the extra-articular suture fixation technique with sutures tied over a button (group B). Biomechanical and histological evaluations were performed at 2, 4 and 8 weeks postoperatively. In biomechanical evaluation, at 2 or 4 weeks 27 of 28 specimens (96%) were pulled out from the femoral tunnel, while one 4-week specimen and all four 8-week specimens failed at the graft's mid-substance. At 2 weeks, the maximum failure load was 25+/-10 N and 24+/-6 N for group A and group B respectively (mean+/-SD). At 4 weeks, the maximum failure load was 42+/-17 N and 35+/-15 N respectively. There were no significant differences in maximum pullout failure load between the groups at 2 or 4 weeks postoperatively. (P=0.887 at 2 weeks and P=0.339 at 4 weeks using ANOVA measurement). Histologically, the bone-attached grafts showed partial bone-to-bone union at the graft-bone tunnel interface at 4 weeks, and complete bony union at 8 weeks. The bone-free grafts exhibited newly formed Sharpey-like collagen fibers at 4 weeks, and strong connection by mature granulation tissue at 8 weeks. Graft-to-bone tunnel healing of bone-attached graft with screw fixation and bone-free graft with extra-articular suture fixation are comparable in terms of biomechanical evaluation during the early postoperative periods.

Animals↗

PubMed2003

Comparison of functional results of nerve graft, vein graft, and vein filled with muscle graft in end-to-side neurorrhaphy.

End-to-side neurorrhaphy is an alternative method in the situation where the proximal part of the nerve cannot be found. When the intact nerve is not close enough to perform end-to-side neurorrhaphy, it will be necessary to use a graft for transporting the regenerating axons. In this study, we tried to find out whether it is possible to use a graft in an end-to-side neurorrhaphy, and compared the nerve graft with possible alternative grafts, i.e., vein and muscle-filled vein grafts. Thirty male Sprague Dawley rats were used, with an average weight of 293 g (range, 250-350 g). All experiments were done on the right side. A 2-cm nerve graft, beginning 1 cm distal to the branching level, was sectioned from the peroneal nerve. A 1-mm epineural window was opened in the tibial nerve. In the first group, the proximal side of this graft was sutured to the tibial nerve side in an end-to-side fashion, and the distal side was sutured to the distal peroneal nerve stump in an end-to-end fashion. In the second group, the right 2-cm jugular vein was harvested, and was used to bridge the defect instead of the nerve graft used in the first group. In the third group, a 2-cm jugular vein filled with fresh skeletal muscle was used to bridge the defect. At 2, 4, 8, 12, 20, and 28 weeks, functional assessment of nerve regeneration was performed, using walking-track analysis. The numbers of myelinated fibers and fiber diameters were measured, and an electron microscopic evaluation was carried out. Based on walking-track analysis and fiber diameters, the differences of all three groups were statistically significant (P < 0.05). While the differences of myelinated fibers between the first and second groups were not significant, the differences between the rest (group 1-group 3 and group 2-group 3) were significant (P < 0.05). Our study showed that, in end-to-side neurorrhaphy, the use of a nerve graft is possible, and a vein graft is also a good alternative, but a muscle-filled vein graft is not.

Anastomosis, Surgical↗

PubMedDate not supplied

Modification of polyetherurethane for biomedical application by radiation-induced grafting. I. Grafting procedure, determination of mechanical properties, and chemical modification of grafted films.

Radiation grafting of monomers onto suitable trunk polymers is a useful tool for tailoring new polymers for special purposes. This technique has been used in the past for the development of biocompatible materials, e.g., by grafting hydrogels onto mechanically stable polymers. In this first part of our work, the radiation grafting of hydrophilic or reactive monomers onto a polyetherurethane film using the pre-swelling technique is described. Following this technique the trunk polymer was swollen in the monomer before irradiation. As monomers 2-hydroxyethyl methacrylate (HEMA), 2,3-epoxypropyl methacrylate (GMA), 2,3-dihydroxypropyl methacrylate (GOMA), and acrylamide (AAm) were used. The kinetics of the grafting reactions were examined, and the distribution of the graft component inside the trunk polymer was investigated by means of infrared (IR) spectroscopy. Surface-grafted as well as bulk- and surface-grafted products could be obtained. The mechanical behavior of the grafted films--especially in the water-swollen state--was examined and compared with that of the pure trunk polymer. In nearly all cases it was found that the tensile strength sigma B and the elongation at break epsilon R decreases as the grafting yield increases. Modification of GMA- and AAm-grafted films via chemical reactions was performed to create new functional groups of biomedical interest. In this manner a diol structure, a carboxylic acid structure, and a sulfonic acid group could be introduced in the grafted polymer. The water uptake of such modified films is increased markedly when compared with that of the unmodified samples.

Biocompatible Materials↗