Obvious Rejection Research Articles

Культура вредна для нас? Современные тенденции осмысления социального функционирования искусства

The critical review of trends in modern sociological interpretations of the artistic culture problems in Western countries presented in this article is based on the analysis of scientific publications of the last two decades. It demonstrates the breadth of the subject field of the sociology of art, the diversity of the author’s concepts and trends in theoretical understanding of artistic life. Today, in the sociology of art, as in other social sciences, there is an obvious rejection of immutable truths and taboos, and the interpretation of empirical facts is often polemical. They increasingly reflect the personality of the author and their attitude to moral and ethical aspects that go beyond the framework of cultural life — social justice and inequality, racial, gender and other problems of modern society. The revision of axiological guidelines and the relativity of modern criteria of truth can give rise to doubts not only about the importance of the empirical study of artistic life, but also about the practical need for public support for art and even about the epistemological potential of science. The desire for absolute freedom of art from external influences, for universal equality in cultural consumption and social justice in the literal sense of the word, sometimes paradoxically turns into a denial of the humanistic essence of art and even leads to statements about the dangers of artistic culture for people. However, most scientists in the West still agree that in order to maintain the positive social role of art, we must continue the attempts to comprehend the challenges posed by the global trends of our time. In this regard, it is extremely important to find common ground for uniting the efforts of art-centric and empirical areas of the sociology of art.

Preparation of Nile tilapia skin collagen powder by low-temperature and comprehensive evaluation of hemostasis and wound healing.

Nile tilapia (hereinafter referred to as tilapia) is a species with high economic value and extensive cultivation. In this study, the low-temperature Nile tilapia skin collagen powder (TSCP) was prepared by liquid nitrogen freeze pulverization. After physical and chemical analysis of its properties, it was found that its characteristics were similar to those of type I collagen. The three-dimensional helix structure of protein peptide is good and non denatured. It shows that cryogenic temperature guarantees the activity of TSCP. In addition, TSCP has good biocompatibility. Specifically, it has good blood compatibility, lacks cytotoxicity, will not cause intradermal stimulation and acute systemic toxicity, and has no obvious rejection after implantation. In the rat liver hemorrhage model and wound repair model, compared with the commercially available bovine collagen powder (BSCP), TSCP has better blood coagulation ability: the shortest hemostatic time (135 s) and wound healing efficiency: the wound healing is obvious on the 14th day. The results of this study indicate that the TSCP is an ideal candidate for hemostatic agents and wound healing dressings.

P2.20: Angiogenesis Promoting Effects of Human Amnion Membrane in Ischemia-Impaired Wound in a Rat Model

Background: Ischemic wounds are intractable and require revascularization for healing. However, many patients with ischemic wounds have serious comorbidity, and revascularization surgery is not necessarily applicable for those patients, resulting in amputation of the lower limbs. Therefore, it would be useful to establish wound dressing materials with revascularization effects. Human amniotic membrane (hAM) has a variety of characteristics that make it potentially useful as a wound dressing material. However, there have been few reports on the angiogenesis promoting effects of hAM in ischemia-impaired wound. The aim of this study was to examine the efficacy of hAM as a wound dressing material for ischemic wounds. Methods: Amniotic membranes were collected from delivered placentas with the consent of a pregnant woman who underwent a cesarean section. Fresh hAM were used within 6 hours of collection. Ischemic wounds were made at abdominal wall of male rats (SD, 9 weeks old, 300-350 g) by ligating the arteriovenous and nerve bundles of inferior abdominal wall and excising the abdomen skin with a diameter of 2.0 cm. Microvessel density (MVD) as an index of angiogenesis was measured by double staining with anti-α-SMA and anti-CD34 antibodies. The density of the number of blood vessels as well as the wound area were compared between hAM group and control group. Results: The wound area after 5 days was significantly smaller in hAM group than in control group (335 vs. 459 mm2, p = 0.0051). The mean value of MVD was significantly higher in hAM group than in control group (19.0 vs. 15.1, p = 0.0026). Histological evaluation showed no obvious rejection of the hAM in this study. Conclusion: This study showed the wound healing effect and the angiogenesis promoting effect of fresh hAM, indicating the usefulness of fresh hAM for treating non-invasively ischemic wounds. Japan Society for the Promotion of Science (JSPS KAKENHI) Grant Number: 20K09138.

The influence of yttrium and manganese additions on the degradation and biocompatibility of magnesium-zinc-based alloys: In vitro and in vivo studies

The repair and regeneration of bone defects are highly challenging orthopedic problems. Recently, Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone. The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration. In this study, we prepared and modified Mg-3 Zn, Mg-3Zn-1Y, and Mg-2Zn-1Mn by hot extrusion, and used Mg-2.5Y-2.5Nd was as a control. We then investigated the effect of additions of Y and Mn on alloys’ properties. Our results show that Mn and Y can improve not only compression strength but also corrosion resistance. The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro, and for this reason we selected it for implantation in vivo. The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction, and the degradation products left no signs of damage to the heart, liver, kidney, or brain. Furthermore, we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.

АНТИПАРТИЗАНСКАЯ ПРОПАГАНДА НЕМЕЦКИХ ВЛАСТЕЙ НА ОККУПИРОВАННОЙ ТЕРРИТОРИИ СОВЕТСКОЙ БЕЛОРУССИИ

The article examines the ideological aspects of the German struggle against partisans in the occupied territory of Soviet Belarus. The author, on the basis of previously unpublished documents of the National Archives of the Republic of Belarus (propaganda publications of the occupation authorities, orders and circulars of the heads of the German General Commissariat, reports of partisans) and a number of historical studies, analyzes the content of German propaganda materials, identifies its main thematic areas, determines the effectiveness of anti-partisan propaganda. The heads of the General District (W. Kube and C. von Gottberg) expressed a special opinion on the methods of anti-partisan struggle. They believed that punitive actions were ineffective and the main stake in the anti-guerilla struggle made on propaganda and involvement of the local population. The author concludes that the massive and large-scale propaganda influence of the German administration was neutralized by an extremely cruel occupation policy (namely, punitive actions of the SS against partisans and the civilian population living in the partisan zone, the genocide of Jews, which caused obvious rejection and fear) as well as partisan counter-propaganda. Attempts to involve the Belarusian population to combating partisans proved to be not very effective. Moreover, the very actions of the German occupation authorities — forced recruitment to work in Germany, as part of numerous collaborationist organizations — forced Belarusians to seek salvation among the partisans.

Comparison of xenogeneic acellular dermal matrix and skin grafts in reconstruction of postoperative defects of hypopharyngeal cancer: A retrospective cohort study.

Successful reconstruction after tumor resection facilitates rapid recovery and retention of good quality of life, and this is important for a successful operation. This study aimed to analyze and compare the application and efficacy of xenogeneic acellular dermal matrix (xeno-ADM) and abdominal skin graft in hypopharynx reconstruction.This is a retrospective cohort study that included 25 patients with posterior hypopharyngeal wall cancer who underwent partial hypopharyngectomy with laryngeal preservation. The patients were divided into 2 groups according to the repair materials used. Eleven patients were treated with xeno-ADM, and 14 patients with abdominal skin grafts for repairing hypopharyngeal mucosal defects. The intraoperative data, postoperative recovery time of eating function, graft contraction, infection and pharyngeal fistula rate, and 1-year survival rate of the 2 groups were analyzed and compared.Compared with skin grafts group (23.1 ± 5.8 days), the recovery time of eating function in xeno-ADM group was shorter (17.3 ± 6.4 days), (P = .026). Also the number of postoperative hospitalization days were less in the xeno-ADM group (18.5 ± 6.7 days) than in the skin grafts group (24.1 ± 5.6 days) (P = .035). Besides, no significant differences were observed in other comparisons between the 2 groups. Also no obvious rejection and severe graft contraction were observed in both the groups. All patients were successfully decannulated.Both xeno-ADM and abdominal skin grafts demonstrated good effects in the reconstruction of hypopharynx, but the recovery time of eating function in patients with xeno-ADM was faster, which may be due to rapid epithelialization. In addition, it avoids trauma of donor sites.

Experimental study on long-term outcome of porcine collagen membrane xenotransplantation in vivo

To observe the long-term outcome and biocompatibility of the porcine collagen membrane (DermalGen) after xenotransplantation in vivo. Twenty Sprague Dawley rats were randomly divided into 2 groups ( n=10). DermalGen were implanted subcutaneously into the dorsum of rats in experimental group, and the rats in control group were treated with sham-operation. At 3, 7, and 15 days and 1, 3, 6, and 12 months after operation, the samples of experimental group were harvested and gross observation, histological observation, CD31 immunohistochemical staining, and transmission electron microscope observation were taken to observe the inflammatory reaction, angiogenesis, and collagen arrangement. The skin tissues of the control group at 12 months were observed and compared. All incisions healed in experimental group, without obvious swelling and inflammatory reaction. The DermalGen was closely contact with the surrounding tissue without obvious rejection, and it was still legible at 12 months. Histological observation of experimental group showed that the infiltration of fibroblasts and inflammatory cells were seen at 7 days. More capillaries and fibroblast cells were seen and the inflammatory response gradually faded at 15 days and 1 month. There were abundant vessels and cells in the DermalGen at 3 months. The angiogenesis and fibroblasts decreased gradually, and the collagen started to format and margin blended simultaneously at 6 and 12 months. The inflammatory cells in experimental group at 15 days and 1 month were significantly more than that in control group ( P<0.05), and no significant difference was found at 12 months between experimental group and control group ( P>0.05). Immunohistochemical staining of experimental group showed that the angiogenesis changed obviously with the time, and the density of vessels decreased significantly at 12 months. Compared with control group, the possitive expressions of CD31 in experimental group at 15 days and 12 months after operation were significantly decreased ( P<0.05), and were significantly increased at 1 month ( P<0.05). Transmision electron microscope observation showed that the arrangement of collagen in grafted DermalGen had no obvious changed when compared with the DermalGen, and vascular endothelial cell, capillarypericytes and fibroblast cells could be seen inside. The DermalGen structure is stable after long-term xenotransplantation and with good tolerogenic property in vivo.

Using axial vibration membrane process to mitigate membrane fouling and reject extracellular organic matter in microalgae harvesting

Membrane fouling caused by algae cells and extracellular organic matter (EOM) is a major challenge in microalgae harvesting. In the present study, the axial vibration membrane (AVM) process can effectively reduce membrane fouling by increasing vibration frequency. An equation was obtained to explain why the vibration frequency has a more important impact on critical flux than the amplitude. During the continuous filtration, the flux decline rate was only 3.6% at the frequency of 10Hz and amplitude of 1cm. While at the frequency of 5 and 0Hz the decline rates were 34% and 64.2%, respectively. At high frequency, AVM can not only prevent the deposition of algae cells on membrane, but also reduce the adsorption of EOM on membrane. Scanning electron microscope and fourier transform infrared spectroscopy analysis showed that AVM can effectively reduce EOM adsorbing on membrane at 10Hz. AVM had better rejections of protein (28–39%) and polysaccharide (about 35%) at 10Hz, compared with 0 and 5Hz. Membranes had obvious rejection of low molecular weight EOM, regardless of at high or low frequency; however, compared to low frequency at high frequency AVM could reject more high molecular weight organics.

The computer assisted bone bank and its application in individual treatment of bone tumor

Objective To investigate the clinical value of a computer assisted bone bank in bone tumor resection and structural allograft bone reconstruction with computer assisted navigation.Methods Bone allografts in the present conventional bone bank in Xijing Hospital were sectionally scanned by CT.Three-dimensional reconstructed images of the CT scans were saved and marked in the digital analytical system to establish a computer assisted bone bank.Before surgery three-dimensional reconstruc ted CT image data of the bone tumor were compared with the allogenic osteoarticular data in the digital bone bank to select an optimum match in bone remodeling segments.Both data were imported at the.dicom 3.0 format into the navigational system to accurately locate borders of the tumor and to cut the allograft bone during the surgery preoperatively designed with the aid of the digital bone bank to get a structural reconstruction.From November 2009 to June 2012,tunor resections and reconstructions under computer navigation assisted by the digital bone bank were performed in 6 patients with malignant bone tumors.The patients were 7 males and 4 females,aged from 13 to 42 years (average,24.7 years).There were 3 cases of giant cell tumor,5 cases of osteosarcoma,2 cases of chondrosarcona and one case of Ewing sarcoma.The oncological and functional outcomes were postoperatively evaluated by the Musculoskeletal Tumor Society 93 (MSTS93) system.Results The computer assisted bone bank obviously shortened the time for selecting allograft bone materials before surgery and improved the matching accuracy,compared with routine preparation of allograft bone.The dissection registration spots in the actual operations matched well with the preoperative three-dimensional reconstructed CT images before surgery,with an average registration error of 0.42 rmm.The 11 patients were followed up from 3 to 30 months (average,15.7 months).Postoperative X-ray images showed that the tumor resection territory and the allograft bone cutting region were totally consistent with the preoperative design in all patients.No limb discrepancy or malformation was observed.No screw loosening or breakage or joint collapse occurred.No obvious immunity rejection,or local recurrence or remote metastasis was observed.The healing between allograft and host bone was achieved after an average of 6.3 months.The average MSTS93 functional score was 25.7 points.Conclusions A digital bone bank can provide accurate information for selecting allograft bone materials before surgery,and allows for individual design of resection and reconstruction protocols which,in combination with computer navigation,may improve the safety and effectiveness of a salvage limb operation. Key words: Bone bank; Bone neoplasms; Surgery, computer-assisted

Clinicopathologic Observations of the Skin in Seven (5 Hand, 2 Face) Composite Tissue Allograft Recipients

Composite tissue allotransplantation has emerged as a new reconstructive surgical technique aiming at restoring non-vital parts of the body, such as limbs and face. It involves transplantation of various tissues including the skin, vessels, nerves, cartilage, bones and immune cells. Among these, the skin is of special importance since it is the most visible and the most antigenic tissue in a composite tissue allograft (CTA), therefore its macroscopic and microscopic observation provides information on the viability of the CTA and on the presence or absence of rejection, possibly requiring adjustments of the immunosuppressive treatment. We report here our clinicopathological observations of the allografted skin of seven CTA recipients (five hands, two face) followed regularly in our hospital. The patients (five men, two women) received a triple immunosuppressive regimen (steroids, tacrolimus (or sirolimus) and mycophenolate mofetil); they were monitored clinically and protocol biopsies were taken at least twice yearly, and whenever rejection was suspected. All of them developed at various times post-graft one or more episodes of rejection, reversed by increasing the dosages of immunosuppressants and by local applications of steroids and tacrolimus. The longest individual clinicopathologic follow-up of the skin varied from 2 to 11.8 years. At the follow-up endpoint (11.8, 8, 4.8 and 3 years respectively), 4 hand-graft recipients had neither clinical nor pathological signs of rejection (Banff grade 0), while the latest one (2 years) showed clinically slight erythema of the forearms and pathologically mild rejection (grade I). The first face-transplant recipient showed microscopically mild and moderate signs of rejection (grades I and II, respectively) on the skin from the face and the sentinel allograft skin, although no obvious macroscopic changes were seen. The second face-grafted recipient had developed over the preceding months fluctuating signs of rejection because of immunosuppressive treatment tapering during courses of chemotherapy for an EBV+ lymphoma. At the latest follow-up (2 years postgraft) his facial skin was erythematous, pigmented and somewhat indurated. Microscopically, signs consistent with grade III rejection were found both on the facial and the sentinel-graft skin, despite an absence of significant dermal inflammation. In all patients, apart from changes related to rejection, the skin showed microscopically a normal structure and contained all main cell types, including cycling keratinocytes, Langerhans cells (of recipient's origin), melanocytes, endothelial cells and axons. Occasional FoxP3+ T-reg and TiA1+ cytotoxic T-cells were found in the skin, even in the absence of obvious rejection. No C4d deposits were found, suggesting that humoral rejection does not occur in CTA. Apart from rejection, cutaneous transplantation-related side-effects were mild (tinea versicolor, molluscum contagiosum, warts), although one basal-cell carcinoma developed 6 years post-graft on the (self) cheek of the female face-transplant recipient. Close clinicopathologic monitoring of the skin seems to be important for the assessment of the quality of the CTA as a whole, and for the detection of signs of rejection. In the majority of cases, the structure of the skin remains normal with a conventional triple immunosuppressive protocol that seems adequate to prevent CTA rejection in the majority of cases.

Introducing new evidence in patent appeals from USPTO

Introducing new evidence in patent appeals from USPTO

Clinical Application and Long-Term Follow-Up Study of Porcine Acellular Dermal Matrix Combined With Autoskin Grafting

The purpose of this study was to investigate the clinical effects of porcine acellular dermal matrix combined with autoskin grafting on full-thickness skin defects using long-term clinical follow-up study and histologic examination. One hundred fifty-two patients with deep burn or trauma hospitalized from February 2000 to July 2003 were repaired with porcine acellular dermal matrix and split-thickness autoskin graft. Take rate of the grafts was calculated on 1 week after operation. Scar hyperplasia was examined on 1, 3, 6, and 12 months after operation. At the same time, the contracture rates of grafted areas were also calculated. Skin biopsy was performed on five patients for histologic examination, as well as transmission electron microscopy 78 months after operation. The take rate of grafts of 116 patients (76.3%) was 100%, and the take rate of the rest of the patients (36 patients, 23.7%) was more than 95%. No one needed skin transplantation for the second time. One hundred twenty-seven patients were followed up on 1 month after operation; grafts showed mild contraction. There was slight cicatricle at skin junction with tender texture. There was no obvious pruritus and blister. One hundred one patients were followed up on 3 months after operation. The graft contraction showed obvious relief with good articular function. Eighty-two patients were followed up on 6 months after operation. The color and texture of the grafts were similar to normal skin without obvious cicatricial hyperplasia. Fifty-eight patients were followed up on 12 months after operation. The grafts were similar to normal skin without obvious rejection. There were no significant differences between the contracture rates at 3, 6, and 12 months and 1 month after the second surgery. Sixteen patients were followed up on 78 months after operation. The appearance of grafts was slightly dry compared with normal skin. Tissue structure of grafts was similar to normal skin with sweat gland-like structure, and sweat gland cells were shown in the dermis. Xenogenic acellular dermal matrix combined with split-thickness autograft can repair full-thickness skin defects and inhibit scar proliferation without obvious immune rejection for long time. Newly formed sweat gland-like structure and sweat gland cells in the dermis may be a new research point for reconstruction of skin function.

Do Today's Sociologists Really Appreciate Weber's Essay The Protestant Ethic and the Spirit of Capitalism?

It is noted that Max Weber is held in very high regard by the majority of contemporary sociologists, while his essay, The Protestant Ethic and the Spirit of Capitalism, is generally considered his most important as well as his most famous work. However attention is drawn to the marked contradiction between the practice of today's sociologists in routinely heaping praise on this essay and the fact that their own self-confessed theoretical statements constitute a direct rejection of Weber's approach. This contradiction is illustrated by demonstrating that although The Protestant Ethic is essentially an examination of the role of motives in human action the concept of motive is effectively missing from contemporary sociology. A possible explanation for this apparent contradiction is then considered in the form of the claim that those theoretical positions favoured by contemporary sociologists could be considered as ‘developed out of’ or ‘descended from’ Weber's theory of ‘motivational understanding'. This however is shown to be an untenable claim, given that the vocabulary of motives perspective, the treatment of motives as reasons, and rational choice theory all represent straightforward rejections of Weber's position. Consequently it is concluded that there remains an unresolved and largely unrecognised contradiction between the iconic status accorded to Weber's essay by contemporary sociologists and their own very obvious rejection of his theoretical approach.

In vitro bioartificial skin culture model of tissue rejection and inflammatory/immune mechanisms

We hypothesized that an in vitro bioartificial skin rejection model using living LSEs grown in tissue culture could be developed for the study of autologous, allogenic, and/or xenogeneic inflammatory/immune mechanisms and topical immunosuppressive drugs. Human fibroblasts were mixed with type 1 rat-tail collagen to form a matrix (4 to 5 days), on which human keratinocytes were seeded. After a keratinocyte monolayer formed, CT cultures were raised to the air-liquid interface for continued growth. In the REJ LSE model, immunocytes isolated from human blood were seeded on top of the NHEK monolayer at the time of air-lifting. Thickness measurements of the acellular keratin and keratinocyte layers, and nuclear/cytoplasmic ratios, in both CT and REJ were made using digital image analysis. Immunostaining with anticytokeratin demonstrated a viable, keratin-producing epidermal layer; staining with anti-TGF-beta suggested a role for this cytokine in the rejection or wound-healing process. The LSE appeared histologically similar to normal human epidermis. Immunocytes added to the REJ cultures caused an obvious rejection response and were clearly identifiable in the gels as CD45+ staining cells. The LSE model appears promising for the study of immune/inflammatory mechanisms, thermal injury, screening antirejection agents that might be applied topically and as an in vitro replacement for skin graft studies in animals.

A mixture of allogeneic dermal tissue and autologous microskin grafting of rabbit skin wound.

In a rabbit model, transplantation of largely expanded microskin grafts (expansion ratio 25 X) were studied. In Group I, the autologous microskin grafts were transplanted onto the full-thickness skin defect on the back of a rabbit and were overlaid with Biobrane. In Group II, the autologous microskin grafts were mixed with allogeneic microdermal substance (expansion ratio 25 X) before the transplantation. The percentage of re-epithelialized area to the total grafted wound was analyzed by means of computerized planimetric analyses of photographs of the grafted wounds on days 11 and 13. Biopsies of the grafted wounds were done. On day 11, the mean percentage of Group I was 72.4% and that of Group II was 82.7%. On day 13, they were 82.3% in Group I and 92.3% in Group II. In Group II, the allogeneic dermal tissue did not cause obvious rejection in the neoepithelium. Histological features showed the existence of allogeneic dermal tissue in the grafted wound. The adding of largely expanded allogeneic dermal substance to autologous microskin grafts in Group II provided better circumstances than that in Group I for re-epithelialization of autologous mciroskin grafts.

Mechanisms of graft rejection in the transplantation of retinal pigment epithelial cells.

The role of activated retinal pigment epithelium (RPE) cells was investigated in the rejection after subretinal transplantation. RPE cells from 7 pigmented rabbits were separated and evaluated regarding their MHC class II expression as the sign of activation. The activation of the RPE cells was augmented with a treatment of 1,000 U/ml interferon gamma (IFN-gamma) for 8 days. These cells were then transplanted into 7 albino rabbits. As control, RPE transplantations without a pretreatment were performed in 7 albino rabbits. Six weeks after the transplantation, the transplanted eyes were enucleated and histology was performed. In culture, without IFN-gamma addition, 11.38 +/- 0.94% of the RPE cells presented MHC class II. After IFN-gamma treatment, this quantity increased to 78.26 +/- 1.46% of the RPE cells. These cells transplanted into the rabbits caused an obvious rejection in the transplantation area which was verified histologically. The control group presented a transplantation area without signs of rejection or inflammation. In culture, some of the adult RPE cells are activated. These cells may accelerate the rejection cascade after transplantation. An elimination of activated RPE cells from the transplant should be recommended before transplantation.

In vitro bioartificial skin culture model of tissue rejection/and inflammatory/immune mechanisms

We hypothesized that an in vitro bioartificial skin rejection model using living LSEs grown in tissue culture could be developed for the study of autologous, allogenic, and/or xenogeneic inflammatory/immune mechanisms and topical immunosuppressive drugs. Human fibroblasts were mixed with type 1 rat-tail collagen to form a matrix (4 to 5 days), on which human keratinocytes were seeded. After a keratinocyte monolayer formed, CT cultures were raised to the air-liquid interface for continued growth. In the REJ LSE model, immunocytes isolated from human blood were seeded on top of the NHEK monolayer at the time of air-lifting. Thickness measurements of the acellular keratin and keratinocyte layers, and nuclear/cytoplasmic ratios, in both CT and REJ were made using digital image analysis. Immunostaining with anticytokeratin demonstrated a viable, keratin-producing epidermal layer; staining with anti-TGF-beta suggested a role for this cytokine in the rejection or wound-healing process. The LSE appeared histologically similar to normal human epidermis. Immunocytes added to the REJ cultures caused an obvious rejection response and were clearly identifiable in the gels as CD45+ staining cells. The LSE model appears promising for the study of immune/inflammatory mechanisms, thermal injury, screening antirejection agents that might be applied topically and as an in vitro replacement for skin graft studies in animals.

Surgical management of ocular surface disorders using conjunctival and stem cell allografts.

The aim of this work was to investigate different surgical options for the repair of the ocular surface, using various extensions of the procedure of limbal stem cell allotransplantation. Straightforward lamellar limbal transplantation was performed in one patient with contact lens induced limbal stem cell failure. A second patient with a neoplastic corneal lesion underwent limbal allotransplantation, followed later by a second procedure in which 360 degrees of limbus and the entire ocular surface was transplanted. A third patient who had suffered extensive chemical burns was treated by penetrating keratoplasty to restore central corneal clarity, followed later by a lamellar allograft comprising a 360 degrees annulus of peripheral cornea to repair the ocular surface. A fourth patient with long standing, chronic trachomatous eye disease underwent allotransplantation of the upper lid tarsal plate and conjunctiva, with reconstruction of the fornix. Finally, a child with Goldenhar's syndrome underwent reconstruction of the medial fornix with autologous buccal mucosa, followed by a lamellar corneal and conjunctival allograft. A stable ocular surface has been achieved in each case and there have been no obvious rejection episodes. Limbal allotransplantation can be extended to engraftment of the entire superficial cornea, limbus, conjunctiva, and tarsal plate in patients with a range of pathologies. We have described the surgical management of five cases which demonstrate the potential of the technique, but which raise questions which still need to be explored.

SIMULTANEOUS LIVER AND RENAL TRANSPLANTATION IN MAN

Advanced chronic renal failure has been thought of as a contraindication to liver transplantation. We present here seven cases of simultaneous kidney-liver transplant performed for combined end-organ failure. Six of the seven patients are alive with functioning grafts with follow-up of from 6 weeks to 32 months. In one case, the patient chronically rejected his liver graft (treated with successful retransplant) while maintaining good function in his kidney. The rate of acute rejection in the liver transplant was only 37.5% compared with 59.3% in the patients undergoing liver transplant only. There were no obvious rejections observed in the kidney transplants. These cases demonstrate the utility of simultaneous kidney-liver transplant in patients with combined kidney and liver failure. Advanced chronic renal failure should no longer be considered a contraindication to liver transplantation.

Evidence that the effector mechanism of skin allograft rejection is antigen-specific.

In vivo rejection responses are initiated by specific T-cell recognition of foreign histocompatibility antigens expressed by tissue allografts, but it is not certain if the effector mechanism mediating the actual tissue injury is also antigen-specific. To directly assess the specificity of the effector phase of in vivo rejection responses, we constructed B6 in equilibrium with A/J allophenic mice that are genetic mosaics whose individual cells express either H-2b or H-2a histocompatibility antigens but not both. Trunk skin from B6 in equilibrium with A/J allophenic mice was grafted onto immunoincompetent H-2b nude mice and allowed to heal and regrow hair that was both black and white, reflecting the genetic mosaicism of the allophenic grafts. One month after engraftment, the H-2b nude animals were reconstituted with syngeneic H-2b T cells reactive against H-2a allodeterminants. An obvious rejection response ensued involving antigen-nonspecific inflammatory destruction of the epidermis and complete hair loss. Despite the intensity of the nonspecific inflammatory response, the allophenic skin grafts survived. Importantly, the allophenic grafts regrew hair and the predominant color of that hair was black, providing visual proof that syngeneic B6 melanocytes and hair follicle cells had not been destroyed. Thus, these results demonstrate that although the intense inflammatory component of skin graft rejection responses is capable of damaging superficial epidermal cells nonspecifically, it does not cause rejection of skin allografts. Rather, rejection of skin allografts is mediated by antigen-specific effector T cells that assess individual cells within the dermis of the graft for expression of foreign histocompatibility antigens.