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B Banner

Publications and source records attributed to B Banner.

At least 55 records · Page 3Linked to original sources
PubMed1990

Transplantation of the small intestine: the pathologist's perspective.

Small-bowel transplantation is now ready for clinical trials. The surgical techniques and methods for immunosuppression and monitoring bowel status have been developed in animal models over the past 30 years. Several attempts at small-bowel transplantation in humans have already been reported. In the course of future trials, pathologists will be involved in the monitoring of the posttransplant course by mucosal biopsies and functional studies, including maltose and xylose absorption tests. The morphology of rejection has been studied in canine and rat models. Activated lymphocytes and plasma cells infiltrate the lamina propria and invade crypt epithelium, causing "cryptitis." Villous blunting ensues, resulting eventually in necrosis. Graft survival without immunosuppression is about 10 days. Under Cyclosporine immunosuppression, a lymphoplasmacytic infiltrate has been noted around nerves and vessels in the submucosa. The overlying mucosa may be relatively normal. End-stage bowel is characterized by a contracted, scarred mass. Due to the large amount of lymphoid tissue in the allograft, graft-versus-host disease is a significant problem in small-bowel transplantation.

Graft Rejection↗
PubMed1989

Normotensive renal failure in systemic sclerosis.

Of 140 patients with "scleroderma renal crisis" encountered during a 33-year period, 15 of 131 (11%) whose blood pressures were recorded were normotensive during this complication. In comparison with 116 patients with hypertension, the normotensive patients significantly more often had microangiopathic hemolytic anemia (90% versus 38%) and thrombocytopenia (83% versus 21%). Pulmonary hemorrhage occurred in 6 normotensive patients. More normotensive patients had received high doses of corticosteroids (prednisone greater than or equal to 30 mg/day) during the 2 months immediately preceding renal crisis (64% versus 16%). A role for corticosteroids in precipitating renal crisis is suggested. The 12-month survival was significantly reduced in the normotensive patients (13% versus 35%).

Acute Kidney Injury↗
PubMed1989

A modified technique of orthotopic transplant of the kidney in rabbits.

In this study kidneys were harvested from bred-for-research cats weighing 4 to 5 kg. General principles of donor bilateral nephrectomy en bloc with aorta, vena cava, renal vessels, and ureters were followed. After the harvest the grafts were placed in lactated Ringer slush. A cuff was prepared on the renal vein over a 10 French plastic tube. The aorta was divided and left in connection with the renal artery at each side. Twenty female checkered Flemish giant rabbits weighing 4.0-6.0 kg served as recipients. After premedication with 40 mg/kg of ketamine, anesthesia was maintained with repeated doses (every 10-15 min) of a 0.1-mL mixture of 5 parts ketamine and 1 part acepromazine diluted 50% in a normal saline. Arterial pressure, CVP, blood gases, and temperature were monitored. Through a limited midline incision a native left nephrectomy was performed. The venous anastomosis was performed with a cuff technique without clamping the vena cava (which causes severe hemodynamic instability); the anastomotic time was 2-3 min. The arterial anastomosis was performed with an end-to-side aorta-to-aorta anastomosis; the anastomotic time was 5 to 7 min. There were no episodes of venous or arterial thrombosis. The donor procedure took approximately 40 min, and the backtable preparation of the graft an additional 45 to 60 min. Preparation of the recipient for the anastomosis took 15 min and the anastomotic time (warm ischemia) was 13 +/- 5 min. In this model suitable for xenograft research the duration of the surgery in the recipient has been greatly reduced because of (1) the previous backtable preparation of the graft, and (2) the cuff technique used for venous anastomosis. The present anesthesia regimen and careful hemodynamic monitoring were also important in the success of this model.

Anesthesia, General↗
PubMed1989

Induction of stable chimerism and elimination of graft-versus-host disease by depletion of T lymphocytes from bone marrow using immunomagnetic beads.

The goal of transplantation is the induction of immunologic tolerance. At present, nonspecific immunosuppression is used to prevent graft rejection and, commonly, graft-versus-host disease (GVHD). Nevertheless, nonspecific immunosuppressive therapy is frequently complicated by infection, malignant tumors, and drug toxicity. In order to examine whether hematopoietic chimerism can be used to induce specific allograft tolerance, we have reconstituted lethally irradiated Lewis rats with ACI bone marrow that has been depleted of T cells with use of immunomagnetic beads. This technique consists of binding OX-19, a mouse anti-rat pan-T lymphocyte monoclonal antibody, to magnetic polymer beads. Mixing of bone marrow or splenocytes with the bead/OX-19 complexes, followed by magnetic separation, results in significant depletion of T cells with minimal nonspecific cell loss. Immunomagnetic T-cell depletion of bone marrow, followed by reconstitution of a lethally irradiated host, allows for the development of stable, mixed hematopoietic chimerae without evidence of GVHD. These hosts are immunocompetent by clinical criteria. Recipients of untreated donor bone marrow that did or did not receive nonspecific immunosuppression demonstrated varying degrees of GVHD and reduced survival. The ability to rapidly and simply deplete T lymphocytes from bone marrow and produce stable, immunocompetent hematopoietic chimerae without GVHD may be an important method for tolerance induction to vascularized allografts.

Animals↗
PubMed1988

Participation of dendritic cells in vascular lesions of chronic rejection of human allografts.

Immunohistochemical techniques were used to investigate the pathogenesis of obliterative arteriopathy, a major obstacle to long-term solid organ allograft survival. T-lymphocytes, macrophages, and proliferating smooth muscle cells made up most of the thickened intima. More importantly, S100-protein-positive dendritic cells were also present in the intima, especially during active inflammation and smooth muscle cell proliferation. These are phenotypic characteristics of tissue "dendritic" cells, pivotal accessory cells in T-dependent immune reactions. Their localisation in the arterial wall signals the presence of an ongoing immunological reaction directed at native constituents of the artery or at exogenous antigens which permeate the damaged vessel wall.

Arterial Occlusive Diseases↗
PubMed1988

Morphologic features of rejection in long-surviving canine small bowel transplants.

We studied morphologic features of small bowel transplants in 25 dogs immunosuppressed by cyclosporine, and preoperative graft irradiation. Graft and host bowel were compared with respect to multiple histologic parameters in a blinded analysis. A lymphoplasmacytic infiltrate in nerves and vessels in submucosa and muscle was present in 18 graft bowels and only 3 host bowels, suggesting that these findings represent a cellular rejection reaction. The other histologic parameters were the same in graft and host bowel. Although the dogs did not exhibit clinical signs of rejection, end-stage scarring of the bowel and death occurred in 6 dogs. The animals did not develop systemic graft-verus-host reaction. These findings indicate that under cyclosporine therapy, a subclinical rejection reaction persists deep in the wall and may remain undetectable in mucosal biopsies, but may progress to destroy the graft.

Animals↗
PubMed1988

Effect of pretransplant graft irradiation on canine intestinal transplantation.

This study was done to define the tolerance of ex vivo administered irradiation to intestinal allograft and to assess the effect of irradiation on the incidence and severity of rejection and graft versus host disease after intestinal transplantation in dogs. Excessive intestinal damage was produced by 2,500 rads, but 750 and 1,500 rads produced no detectable acute or chronic damage in dogs observed from 100 days to two years. Using cyclosporine for postoperative immunosuppression, 1,500 rads reduced the incidence of acute (p = 0.05) and chronic rejection (p = 0.08), yet did not impair intestinal absorption of cyclosporine. The greatest improvement in survival occurred with 750 rads (p = 0.02). Histologic evidence of graft versus host disease appeared in the native small intestine in two of four long term surviving dogs receiving a nonirradiated graft but in none of the dogs receiving irradiated grafts. Irradiation of the graft may be a promising adjunct in the search for a clinically applicable method of intestinal transplantation.

Animals↗
PubMed1987

Prolongation of pig-to-dog renal xenograft survival by modification of the inflammatory mediator response.

The pathogenesis of hyperacute renal rejection consists of a nonspecific effector cascade that invokes most of the components of a typical acute inflammatory response. Platelet-activating factor (PAF) represents the most recent and perhaps the most significant mediator and promoting agent of this phenomenon. These studies evaluated SRI 63-441, a novel, synthetic, and the most potent PAF receptor antagonist available, alone and in combination with other prostanoids, for their ability to influence this response and to prolong renal xenograft survival and function in a model of pig-to-dog heterotransplantation. Inhibition of PAF by SRI 63-441 alone, at the dosage and schedule used in these experiments, did not significantly prolong xenograft survival or function. However, the combination of SRI 63-441 with either prostacyclin (PGI2) or prostaglandin E1 (PGE1) infusion demonstrated significant synergism, and resulted in a 6-9-fold increase in kidney survival and a 3-20-fold increase in urine output. Neither PGI2 nor PGE1 infusions alone significantly influenced this xenograft model. Electromagnetic flow studies demonstrated significantly delayed diminution in renal artery blood flow in the combination-treated animals. Serial and end-stage histologic examination of kidneys receiving combination therapy demonstrated a delayed onset of the pathologic deterioration and an overall amelioration of the entire process. These studies demonstrate that significant abrogation of a rapid and violent form of hyperacute rejection can be achieved solely by the pharmacologic manipulation of the inflammatory mediator response.

Alprostadil↗
PubMed1987

The definition of ABO factors in transplantation: relation to other humoral antibody states.

The first examples of hyperacute rejection of renal hemografts were seen almost 25 years ago when kidneys were transplanted to ABO incompatible recipients whose plasma contained antigraft isoagglutinins. Hyperacute rejection caused in sensitized recipients by lymphocytotoxic antibodies is similar in that the immune reaction triggers an acute inflammatory reaction that leads to widespread thrombotic occlusion and devascularization of the graft. The events after xenotransplantation between certain species are essentially the same. Potential strategies to avoid the precipitating antigen antibody reaction or to mitigate the resulting effector cascade are described.

ABO Blood-Group System↗
PubMed1979

Chemodectoma in the mid-thyroid region.

A chemodectoma (non-chromafin paraganglioma), which presented as a neck mass in the mid-thyroid region, is reported in a 36 year old female. Clinically, it resembled a thyroglossal duct cyst and on frozen section it looked like a thyroid adenoma.

Adult↗