Chemical burns due to blood pressure cuff sterilized with ethylene oxide

This paper reports two unusual instances of ethylene oxide burns that were caused by the blood pressure cuff sterilized with ethylene oxide. It is suggested that the mechanical compression caused by the blood pressure cuff facilitated penetration of ethylene oxide residues into tissues and contributed to the degree of tissue damage.     

Allogeneic implantation of the tendon tissue sterilized with gaseous ethylene oxide in experiment

The implantation of the allo-tendon tissue sterilized with gaseous ethylene oxide was carried out in 51 while rats. Results of histological investigations are described and a comparative estimation is given of durability of the properties of ethyleneoxide sterilized allotendons of the human with the anterior cruciate ligament and dermal tissue. A conclusion is made that it is possible to use the tendon allotransplants in clinical practice.     

Arguments in favor of adipocyte grafts with the S.R. Coleman technique

The main criticism against fat reinjection procedures is related to whether it is possible to graft adipocytes or not. The ideal solution would be to perform biopsies a few months after the operation to check the evolution of the grafted tissue, but such an approach would be difficult to accept for our patients. To overcome this difficulty the authors have compiled all the arguments that plead in favor of adipocyte grafts when Coleman's technique is used. Peer demonstrated in animal studies that it is possible to graft fatty tissue and that more resorption occurs when the fragments are large in size. The histologic studies have shown that the different stages of Coleman's technique do not alter the viability of the adipocytes. A disorganization of the architecture of the lobules is observed, but this does not compromise the theory of adipocyte grafting. An MRI study, performed on ten patients, demonstrated that the reinjected fat cells persist several months after the procedure. These fat cells presented the same characteristics as the patient's native fat in the surrounding area. This impression was confirmed by histological analysis of the reinjected fatty tissue 18 months after the graft. Finally, the clinical results obtained on over 200 patients treated for various indications in plastic and cosmetic surgery lead us to believe that it is possible to perform grafts of fatty tissue.     

Mechanical strength of cortical allografts with gamma radiation versus ethylene oxide sterilization

We investigated the effects of gamma irradiation versus ethylene oxide (ETO) sterilization on the mechanical strength of cortical bone grafts. Tibias were collected from cadavers of mature goats. Sixty test specimens were randomized into four groups: fresh (no processing), frozen (freezing at -70 degrees C), gamma-irradiated, and ETO-sterilized specimens. Torsion, three-point bending, and compression testing were separately performed with a material testing machine. Parameters studied included maximum stress, strain, deflection, extension, load, shear modulus, and E-modulus. Compared with findings for the fresh specimens, findings were as follows for gamma-irradiated specimens: maximal shear modulus, reduced by 48%; shear stress, by 55%; deflection, by 71%; bending stress, by 51%; bending strain, by 74%; extension, by 60%; and compression strain, by 50%. However, there were no reductions in those parameters for the frozen specimens or the ETO-sterilized specimens. These findings confirm that shear, bending, and compression strength of cortical allografts are weakened by gamma irradiation at room temperature. To maintain optimum mechanical properties, ETO sterilization of allografts is better than gamma sterilization, especially for cortical bone, because it is usually used in load-bearing settings.     

Fracture resistance of gamma radiation sterilized cortical bone allografts.

Gamma radiation is widely used for sterilization of human cortical bone allografts. Previous studies have reported that cortical bone becomes brittle due to gamma radiation sterilization. This embrittlement raises concern about the performance of a radiation sterilized allograft in the presence of a stress concentration that might be surgically introduced or biologically induced. The purpose of this study was to investigate the effect of gamma radiation sterilization on the fracture resistance of human femoral cortical bone in the presence of a stress concentration. Fracture toughness tests of specimens sterilized at a dose of 27.5 kGy and control specimens were conducted transverse and longitudinal to the osteonal orientation of the bone tissue. The formation of damage was monitored with acoustic emission (AE) during testing and was histologically observed following testing. There was a significant decrease in fracture toughness due to irradiation in both crack growth directions. The work-to-fracture was also significantly reduced. It was observed that the ability of bone tissue to undergo damage in the form of microcracks and diffuse damage was significantly impaired due to radiation sterilization as evidenced by decreased AE activity and histological observations. The results of this study suggest that, for cortical bone irradiated at 27.5 kGy, it is easier to initiate and propagate a macrocrack from a stress concentration due to the inhibition of damage formation at and near the crack tip.     

Long-term in vivo wear performance of porous-coated acetabular components sterilized with gamma irradiation in air or ethylene oxide

This study evaluated the long-term in vivo wear performance of 2 groups of well-functioning cementless acetabular cups sterilized by different methods. The first group included 31 hips that were implanted with AML TriSpike cups (DePuy, Warsaw, IN) sterilized by gamma-irradiation in air. The second group included 28 hips implanted with Arthropor cups (Joint Medical Products, Stamford, CT) that were sterilized with ethylene oxide. Time-dependent variations in the radiographic wear rates were compared within each group. Changes in the wear rates between 4- and 16-year follow-up times for the TriSpike cups were not significant (P=.09), and there was no evidence to suggest a trend toward substantially increasing wear rates with longer follow-up times. Among the Arthropor cups, the wear rates remained relatively constant between 2 and 14 years of follow-up evaluation. Although clinically apparent late increases in radiographic head penetration rates were not evident, we will continue to monitor all patients for evidence of accelerated wear at late follow-up.     

Repair of nasal septal perforations with tragal cartilage and perichondrium grafts

Indications for repair of nasal septum perforations include excessive crusting, recurrent bleeding, whistling, and pain. Large subtotal perforations usually are less symptomatic, but smaller defects (less than 1 cm) may need repair. Tragal cartilage with perichondrium autograft was used to repair these perforations. After the septal defect was debrided, this free graft was harvested and used to fill the defect. This technique was attempted in ten patients with septal perforations, none secondary to systemic illnesses. Nine of these patients had successful closure of their perforations.     

Studies of residual alkali on intraocular lenses sterilized with NaOH

We measured the effects of pH changes after water washings of polymethylmethacrylate (PMMA) intraocular lenses sterilized in 10% sodium hydroxide (NaOH). Whereas inserting the base-sterilized lens directly into the eye causes a large pH change in the local area of the implant, three separate washings of the NaOH-treated implant in 15 ml of water eliminates this change. No buffer is required.     

Healing of cortical bone grafts in athymic rats.

We studied healing of allogeneic and syngeneic cortical tibial segment grafts in athymic and normal rats. After 3, 6, and 12 weeks, the weight, circulation, and mineralization rate of the healing segment, and mechanical strength and stiffness of the healing tibia were measured. There were no differences between allogeneic and syngeneic grafts in athymic and normal animals at 3 or 6 weeks. After 12 weeks, the vascularization and mineralization of the grafts, but not of the surrounding callus, were smaller in the allogeneic grafts in the normal recipients than in the other groups. Also after 12 weeks, the stiffness of the healing tibiae was less in allogeneic grafts in normal recipients than in the other groups. The strength of the allogeneic grafts was less than the strength of the syngeneic grafts in both athymic and normal recipients. This suggests that T-cell-mediated rejection is responsible for decreased vascularization and mineralization of allogeneic bone and that the difference in strength between allogeneic and syngeneic grafts is not due to T-lymphocyte graft rejection.     

Graft and patient outcomes among recipients of renal grafts with multiple arteries

Anastomosis of multiple renal arteries in living donor kidney transplantation is technically demanding. Previously this condition was considered a relative contraindication to use of the donor, due to an increased risk of vascular and urologic complications. We conducted this retrospective study to determine the prevalence of multiple renal arteries in kidney transplants and their relation to graft and patient survival acute tubular necrosis, as well as vascular and urologic complications for comparison with the outcomes of recipients of single-artery grafts. Among the 1425 patients who underwent renal transplantation at our center, between November 1975 and March 2003 the present analysis concerned the most recent 1095 recipients. Seventy-nine (7.2%) cases required multiple-artery anastomoses (group I) and 1016 (92.8%) a single-artery anastomosis (group II). There were no significant differences between groups I and II with respect to creatinine clearance at 1 year, cold ischemia time at 1 year, or serum creatinine values at 1, 2 or 5 years (P <.05 for all). There were also no significant differences between the groups with respect to rate of posttransplantation hypertension (P =.67), acute tubular necrosis (P =.55), or number of acute rejection episodes (P =.34). The respective graft survival rates at 1 and 5 years posttransplantation were 95.1% and 73.2% in group I and 95.0% and 79% in group II. The corresponding patient survival rates were 95% and 88% for group I and 97.1% and 83.1% for group II. These findings indicate that kidney grafts with multiple arteries may be used with excellent results.     

The resurfacing of adult rabbit articular cartilage by multiple perforations through the subchondral bone.

The repair of articular cartilage removed from the femora of adult rabbits at the knee was studied. When multiple perforations were made through the subchondral bone a cartilaginous material, staining heavily with safranin O, first filled the holes. This material resembled hyaline cartilage, and by twelve months there was complete resurfacing of the joint, although the material lost its hyaline appearance after eight months and at one year it resembled dense collagenous tissue.     

Incorporation of nonviable bone grafts. Autoclaved autogeneic and frozen allogeneic bone grafts compared in the rabbit

In 14 adult rabbits the middle third of the ulna was resected bilaterally followed by reimplantation of resected bone after autoclaving on one side and transplantation of allogeneic bone on the other. In 7 animals the bilateral implants were supplemented with allogeneic bone matrix. The reconstructions were studied in vivo by serial radiography, scintigraphy, and bone mineral determination. The animals were killed at 16 weeks, and the ulnar reconstructions further studied by high resolution radiography, 45Ca autoradiography, and histology. In both types of nonsupplemented reconstructions, new bone formation was poor; nonunion occurred in three out of seven autoclaved reimplants and in five out of seven allogeneic transplants. Supplemented with allogeneic bone matrix, both types of reconstructions exhibited abundant new bone formation and complete incorporation of all implants. Enhancement of new bone formation is probably more important than the type of nonviable bone graft chosen for reconstruction of large skeletal defects.     

Improved survival of transplanted cortical brain tissue grafts by iloprost in rats.

The cytoprotective effect of iloprost on the viability and survival of embryonic cortical brain tissue grafts was examined ultrastructurally under light and electron microscopy before and 4 weeks after transplantation surgery. It was shown that neural grafts stored in iloprost solution (50 ng/mL) for 3 hours were more or less in a normal cytoarchitecture compared with saline-preserved grafts. Moreover, it was demonstrated that 4 weeks after transplantation, graft tissues stored in iloprost solution for 3 hours before implantation maintained a successful survival. Thus, a higher cellular population with new vascularization areas and preservation of myelin formation were accepted as a desirable integration of the graft tissue into the host brain tissue. The mechanism of action of iloprost is discussed.     

Repair of articular defects by perichondrial grafts. Experiments in the rabbit

A defect was created in the articular cartilage of the rabbit knee leaving the subchondral bone intact. The lesion was repaired by an autologous graft of costal perichondrium and fixed with fibrin glue. The result was compared with a nontreated defect in the contralateral knee. In 26 out of 30 knees, graft fixation proved to be adequate. In the grafted group the perichondrium developed macroscopically and histologically into normal hyaline cartilage. The nongrafted defects showed only limited repair.     

Analysis of neonatally induced tolerance of H-2 alloantigens. IV. Graft adaptation in long-term tolerated grafts

Acceptance of orthotopic test skin grafts bearing putative tolerogenic H-2 determinants proves to be the most stringent criterion for the existence of neonatally induced transplantation tolerance. The large majority of long-standing grafts retain their original antigenicity--that is, they are rejected when tolerance is abolished by infusions of immunocompetent cells syngeneic with the tolerant host; and they remain immunogenic--that is, they induce their own rejection when excised and placed on naive recipients syngeneic with the tolerant animal. However, the ability of these long-standing grafts to reflect concordantly the alloreactive potential of peripheral lymphoid cells of tolerant mice deteriorates in time. A minority of tolerated grafts lose their ability to express their genetic endowment of H-2 alloantigens in an immunogenic form through a process of graft adaptation. Because the majority of long-standing Ia-disparate grafts remain immunogenic when transplanted to naive recipients, the adaptation process can not be ascribed exclusively to repopulation of original epidermal Langerhan's cells with similar cells of host origin.     

Acute gastroduodenal perforations associated with use of crack.

Crack, the free-base form of cocaine, was introduced as an illicit street drug in 1986. Since then, we have noted a significant increase in acute gastroduodenal perforations. Between 1982 and 1986, we treated 11 patients with such perforations. This represents a constant occurrence rate of 6% of hospital admissions for peptic ulcer disease. Since 1986 we have treated 16 patients with gastroduodenal perforation, which yields an occurrence rate of 16%. Nine of the 16 patients had a close temporal relationship between the use of crack and the onset of their perforation. This group was younger and disproportionately comprised of male patients. These findings led us to believe that there may be a pathogenic relationship between the use of crack and acute gastroduodenal perforation, and the clinician should be aware of the various potential complications of this new drug. This relationship also raises questions about the exact pathophysiology of peptic ulcer disease.