Multicystic, heterogeneously enhancing meningioma in an octogenerian

A multicystic meningioma in an octogenerian whose tissue diagnosis was ill-defined and misleading on preoperative neuroradiologic imaging is presented. Nauta has described four cyst types that can develop in cystic meningiomas. We report the first case in which three cyst types are demonstrated concurrently, describe the histopathology and surgical management. This case represents a rare variant of a common tumour in an unusual age group, and underscores the need for definitive biopsy and resection as indicated. Furthermore, the diagnosis of multicystic meningioma does not favour an aggressive histopathology in this case.

Recellularization of heart valve grafts by a process of adaptive remodeling

The objective of this study was to investigate if function and durability of connective tissue grafts stems from in vivo revascularization and recellularization. Viability is important for durable valve performance, demonstrated by pulmonary autografts. A pattern of in vivo recellularization occurs in xenogeneic or allogeneic heart valves decellularized prior to implantation, dictated by the tissue matrix and functional biomechanics. Porcine or sheep heart valves were decellularized with the SynerGraft antigen reduction process (a common treatment process to remove all histologically demonstrable leaflet cells), and implanted as pulmonary (n = 11) or aortic valve (n = 9) replacements in sheep. Sheep allograft pulmonary valves (n = 4) were implanted as pulmonary valve replacements. Recellularization was evaluated histologically after 3, 4, 5, 6, and 11 months, with cell phenotypes identified using specific antibodies. SynerGraft heart valves were progressively recellularized beginning with an initial cellular infiltrate, and subsequent repopulation with mature interstitial cells. This process occurs in the conduit and then in the leaflet, and is associated with revascularization of the graft. Functional, fully developed fibrocytes, actively synthesizing type I procollagen (antibody probe) were present within 3 months. As the process matured cell density and distribution became similar to native valve leaflets with localization of smooth muscle actin positive cells at the ventricularis/spongiosa interface. After 11 months, leaflet explants had no detectable inflammatory cells, were as much as 80% repopulated, and had a distribution of smooth muscle actin positive cells similar to that of the natural leaflet. SynerGraft- treated heart valve implants are repopulated by a process typical of adaptive remodeling following implantation. This antigen reduction treatment is the first successful tissue engineering effort obtaining an implant with mature recipient cells capable of matrix protein synthesis. Normal early valve function and durability is maintained.

Incipient erosion of biostabilized sediments examined using particle-field optical holography

Laser holography allows images of three-dimensional space at ultra-high resolution to be recorded onto photographic plates. Recorded scenes can be "replayed" with a second laser beam into free space and optically "interrogated" using either a microscope or a camera by sequentially focusing on increasing distances from the hologram in the field of view (optical sectioning). From these sections, information on the relative locations and orientation in space of suspended particles as well as the morphology of particles can be obtained. This paper examines the utility of "in-line" laser holography to discriminate the size and the morphology of sand particles eroded under turbulent shear flow during benthic sediment transport. The influence of a commercially available adhesive polymer (xanthan gum, derived from the bacterium Xanthomonas campestris) on sediment stability and resuspended particle morphology is described. The major implications for carbon and sediment cycling within estuaries are highlighted.

Transformation of nonvascular acellular tissue matrices into durable vascular conduits

BACKGROUND

Prosthetic grafts commonly used for vascular reconstruction are limited to synthetics and cross-linked tissue grafts. Within these devices, graft infections are common, compliance mismatch is significant, and handling qualities are poor. Natural biological tissues that are unfixed have been shown to resist infections and be durable and compliant. A natural biological matrix that could be remodeled appropriately after implantation would be a desirable graft for vascular reconstruction.

METHODS

SynerGraft tissue engineering strategies have been used to minimize antigenicity and produce stable unfixed vascular grafts from nonvascular bovine tissues. These grafts have replaced the abdominal aortas of 8 dogs that have been followed for up to 10 months.

RESULTS

Early evaluation indicates rapid recellularization by recipient smooth muscle actin positive cells, which become arranged circumferentially, into the media. Arterioles were present in the adventitial areas and endothelial cells were seen to cover lumenal surfaces. After 10 months, grafts were patent and not aneurysmal.

CONCLUSIONS

These data indicate that SynerGraft processing of animal tissues is capable of producing stable vascular conduits that exhibit long-term functionality in other species.

Decellularized human valve allografts

BACKGROUND

Variable performance of allograft tissues in children and some adults may be linked to an immune response and could be mitigated by reducing implant antigenicity.

METHODS

As endothelial and fibroblast cells are the likely source of valve antigenicity, human (CryoValve SG) and sheep pulmonary valves were decellularized using the SynerGraft treatment process. Treated valves were evaluated in vitro using histochemical, biomechanical, and hydrodynamic methods, and compared with standard cryopreserved valves. Four SynerGraft-treated and two cryopreserved sheep pulmonary valves were implanted as root replacements in the right ventricular outflow tract of growing sheep and monitored echocardiographically and histologically at 3 and 6 months. CryoValve SG human pulmonary valves were implanted in 36 patients.

RESULTS

SynerGraft treatment reduced tissue antigen expression but did not alter human valve biomechanics or strength. Decellularized sheep allograft valves were functional during the implantation period, and, they became progressively recellularized with recipient cells. In humans, CryoValve SG pulmonary valves did not provoke a panel reactive antibody response.

CONCLUSIONS

SynerGraft decellularization leaves the physical properties of valves unaltered and substantially diminishes antigen content. Reduction in implant cellularity enables host recellularization of the matrix, which should favorably impact long-term graft durability.

Cellular mechanisms of alloimmune non-responsiveness in tolerant mixed lymphocyte chimeras induced by vascularized bone marrow transplants

It has been demonstrated that the development of stable mixed lymphocyte chimerism is associated with alloimmune tolerance induction in vascularized bone marrow transplant (VBMT) recipients. The underlying mechanisms of immune non-responsiveness in tolerant VBMT chimeras remains unclear. Our VBMT model involves the transplantation of a parental donor limb (Lewis rats) onto a hybrid (Lewis x Brown Norway) F1 recipient. Tolerogenic mechanisms and cellular immune regulation to self and host allodeterminants were investigated during the early post-transplant phase of tolerance induction. Flow cytometric analysis of sIg+-depleted experimental peripheral blood lymphocytes from tolerant VBMT recipients demonstrated low level stable mixed immune chimerism. Chimeric cells tested for responsiveness against self-LEW determinants showed activated proliferation and immune dysregulation 30 days post-transplantation. However, direct immunocytolytic activity against LEW determinants was not found. Tolerant chimeras also demonstrated elevated cellular proliferation and cytolytic responses against host-specific BN allodeterminants at 30 days. Consistent with these in vitro findings, limited clinical signs compatible with GVH reactivity were evident in vivo at this time. Following this initial period, the tolerant VBMT animals returned to normal clinical condition and remained otherwise healthy throughout the study. Consistent with these results, VBMT chimeras then showed declining proliferative responses from the elevated values seen at 30 days against self-LEW determinants. Proliferative and immunocytolytic responses also decreased against host-specific BN allodeterminants from peak levels at 30 days. In conclusion, these results provide evidence that the initial phases of tolerance induction in VBMT chimeras consist of self- and alloimmune regulation that follow an early period of immune dysregulation. Sequential phases of immune dysregulation and re-regulation elucidated in VBMT stable mixed chimeras within the first 100-day period may represent important mechanisms of tolerance induction.

Mechanisms of unresponsiveness associated with pretransplant blood transfusion-cyclosporine-induced mixed lymphocyte chimerism

Multiple pretransplant blood transfusions while under limited daily cyclosporine cover (PTBT-CsA) induce extensive rat renal allograft survival and antigen-specific non-responsiveness. The underlying mechanisms of this extensive allograft survival are not yet fully understood. We hypothesized that one of the potential contributing mechanisms to tolerance induction in PTBT-CsA-treated kidney recipients is the development of stable mixed chimerism, putatively due to the proliferation of stem cells capable of haematopoiesis in the transfused blood. BN rats served as whole blood and kidney donors. LEW rats served as recipients of the PTBT-CsA protocol and BN kidney transplants. Three weekly transfusions were given under concomitant limited CsA cover. Following these multiple primary sensitizations, antigen-specific splenic cellular responsiveness in vivo was normal in comparison with naive animals. However, these experimental splenocytes were non-specifically suppressed against third-party allodeterminants. At 100 days post-transplantation (T100) following tolerance induction to kidney allografts (secondary challenge), in vivo adoptive transfer experiments demonstrated the existence of potent splenic suppressor cells. In vitro suppressor cell assays confirmed that these cells were non-specific suppressor cells. However, following chimerism stabilization at T130, splenic antigen-specific suppressor cells became exclusively expressed in the tolerant animals, replacing the non-specific suppressor cells. At this time, splenic microchimerism was at peak levels and remained stable from T100 to T130. In conclusion, these findings demonstrate that sequential mechanisms of suppressor cell network expression are induced within a chimeric environment by blood-CsA immune modulation. Stable mixed lymphocyte chimerism and related immunomodulatory mechanisms may, therefore, play an important tolerogenic role in blood-CsA-induced non-responsiveness and in the beneficial effect of blood transfusion.

Transpecies heart valve transplant: advanced studies of a bioengineered xeno-autograft

BACKGROUND

Tissue engineering approaches utilizing biomechanically suitable cell-conductive matrixes should extend xenograft heart valve performance, durability, and growth potential to an extent presently attained only by the pulmonary autograft. To test this hypothesis, we developed an acellular, unfixed porcine aortic valve-based construct. The performance of this valve has been evaluated in vitro under simulated aortic conditions, as a pulmonary valve replacement in sheep, and in aortic and pulmonary valve replacement in humans.

METHODS

SynerGraft porcine heart valves (CryoLife Inc, Kennesaw, GA) were constructed from porcine noncoronary aortic valve cusp units consisting of aorta, noncoronary aortic leaflet, and attached anterior mitral leaflet (AML). After treatment to remove all histologically demonstrable leaflet cells and substantially reduce porcine cell-related immunoreactivity, three valve cusps were matched and sewn to form a symmetrical root utilizing the AML remnants as the inflow conduit. SynerGraft valves were evaluated by in vitro hydrodynamics, and by in vivo implants in the right ventricular outflow tract of weanling sheep for up to 336 days. Cryopreserved allograft valves served as control valves in both in vitro and in vivo evaluations. Valves were also implanted as aortic valve replacements in humans.

RESULTS

In vitro pulsatile flow testing of the SynerGraft porcine valves demonstrated excellent valve function with large effective orifice areas and low gradients equivalent to a normal human aortic valve. Implants in sheep right ventricular outflow tracts showed stable leaflets with up to 80% of matrix recellularization with host fibroblasts and/or myofibroblasts, and with no leaflet calcification over 150 days, and minimal deposition at 336 days. Echocardiography studies showed normal hemodynamic performance during the implantation period. The human implants have proven functional for over 9 months.

CONCLUSIONS

A unique heart valve construct has been engineered to achieve the equivalent of an autograft. Short-term durability of these novel implants demonstrates for the first time the possibility of an engineered autograft.

Site-specific immunosuppression: mechanisms of cellular immunosuppression that are operative at local and systemic levels

The cellular mechanisms by which topical cyclosporine A (tCsA) induces site-specific immunosuppression were investigated. Experiments were designed to elucidate how cyclosporine A (CsA) suppresses activated immunocytes in animals that are undergoing local alloactivation and concomitant tCsA immune suppression. Lewis rats received dual Lewis x Brown Norway rat skin allografts; the rats were treated with systemic CsA (sCsA) at 8 mg/kg/day for 10 days after grafting and then tCsA and vehicle thereafter. CsA added to mixed lymphocyte reactions 24 hours after culture initiation modeled the local effects of CsA on alloactivated immunocytes, and tCsA in conjunction with limited sCsA prolonged local skin allograft survival. CsA inhibited both antigen-specific and nonspecific activated alloresponses of immunocytes from animals that had received allografts and that underwent limited sCsA treatment only in a dose-dependent manner. When tCsA had been applied, immunocyte responses to a nonspecific antigen were extremely CsA-resistant as compared with those induced by antigen-specific suppression. However, this nonspecific alloresponse was fully suppressible with the use of elevated CsA doses (66 microg/mL); thus alloresponding immunocytes were significantly more sensitive to CsA if they were challenged with the donor antigen and preexposed to limited sCsA followed by tCsA in vivo.

The SynerGraft valve: a new acellular (nonglutaraldehyde-fixed) tissue heart valve for autologous recellularization first experimental studies before clinical implantation

The durability of current bioprosthetic heart valves is diminished by glutaraldehyde-associated leaflet calcification or by the associated absence of a cellular component capable of repair of wear-related damage. As a novel tissue engineering approach to improving replacement heart valve durability, we have developed a decellularization process to replace the use of cross-linking to limit xenograft antigenicity. The effectiveness of this process was assessed in a weanling sheep right ventricular outflow tract reconstruction model where valve function, calcification, and recellularization were examined. Porcine aortic valves were decellularized by a process designed to remove all histologically demonstrable leaflet cells. Stentless, bioprosthetic valves were fabricated from acellular tissues, cryopreserved, sterilized, and then implanted as pulmonary valve replacements in 4- to 6-month old female Suffolk sheep. Sheep aortic valves were implanted as allograft control subjects. After 150 days, the grafts were explanted and assessed histologically and by atomic absorption spectrophotometry for calcium content. All valves were hemodynamically functional at explant. Histological examination showed intact leaflets with in-growth of host fibroblastoid cells in all explanted porcine valves and no evidence of calcification. Porcine leaflet calcium content was unchanged over the duration of the implant (1.0+/-1.2 vs 1.5+/-1.8 mg/g dry weight, P = ns). Decellularization can stabilize xenogenic heart valves. Lack of calcification of acellular aortic leaflets suggests that prolonged durability of such valves is attainable without the use of cross-linking agents. The repopulation of the leaflet matrix offers additional promise of durability based on revitalization of the graft in vivo.

Composite tissue allografts in rats: IV. Graft-versus-host disease in recipients of vascularized bone marrow transplants

This laboratory has used a composite tissue allograft model as a vehicle for studies on a new type of bone marrow transplant, the vascularized bone marrow transplant. The model consists of a rat hind limb transplant that incorporates integumentary musculoskeletal, and lymphopoietic tissues. These transplants, in comparison with conventional marrow transplants, have the advantage of providing a syngeneic microenvironment and immediate engraftment of both mature and progenitor hemopoietic cells at the time of transplantation. The characteristics of graft-versus-host disease were studied in this model. Lewis X Brown Norway F1 (LBN RT-1(1+n)) rats received hind limbs from Lewis (LEW RT-1(1)) donors (n = 19). Animals were observed daily for signs of graft-versus-host disease. Necropsies were performed. A minority of animals developed lethal disease (7 of 19 recipients) and demonstrated cachexia with concomitant histopathologic changes of the disease. Acute and chronic groups emerged with distinct clinical courses, which are similar to other models of this disease. Recipients of vascularized bone marrow transplants (limb transplants) showed clinical and histopathologic changes of the disease. The transplants may be used as a model of graft-versus-host disease in humans. Most interestingly, the transplant has a lower incidence of disease compared with other methods of bone marrow transplantation and represents an alternative to conventional bone marrow transplantation, which deserves further exploration. It may be possible to develop a new technique for bone marrow transplantation based on this surgical approach. It is proposed that the transfer of vascularized blocks of bone/marrow into prospective recipients as opposed to cellular bone marrow transplants may be preferable.

A Rapid and Sensitive Cellular Enzyme-Linked Immunoabsorbent Assay (CELISA) for the Detection and Quantitation of Antibodies against Cell Surface Determinants II. Optimal Reagent Concentrations and Predictive Analysis

A cellular enzyme-linked immunosorbent assay (CELISA) was developed for the detection and quantification of antibodies elicited against allogeneic cell surface determinants. The technique uses a solid-phase cell matrix created by fixing cells with a mild formalin solution onto the bottom of a 96-well microtiter plate. A primary layer of alloantisera is first reacted against rat target cells. The secondary antibody, peroxidase conjugated antirat IgG, is then added to each well and serves as the second sandwich layer. Optimal reagent concentrations were determined by serial dilution analysis of various cell concentrations and secondary antibody dilutions. It was found that 200,000 cells per well was the optimal target cell concentration. However, 100,000 cells per well was also sufficient to run the assay with acceptable performance characteristics. Even lower cell concentrations of 10,000 and 20,000 cells/well, although not optimal, also produced acceptable results. Secondary antibody concentration with respect to the optimal cell concentration was determined to be 1:500. At 200,000 cells per well and a 1:500 secondary antibody dilution, the assay presented excellent coefficients of determination and high positive to negative ratios. The reaction was found to be very sensitive in yielding high antibody titers with low background levels and could be defined mathematically as a linear-log function. Titers of multiple unknown alloantibody samples were easily and accurately predicted in an automated manner by regression analysis form known standards. This immunoassay will be useful in studies of cell surface determinant expression and quantitation of antibodies reactive to such markers.

Graft-versus-host disease in limb transplantation: digital image analysis of bone marrow and TGF-beta expression in situ using a novel 3-D microscope

A subpopulation of parental to hybrid VBMT recipients developed characteristic clinical and histopathologic manifestations of GVHD. These changes are similar to those seen in human GVHD secondary to bone marrow transplantation. Human GVHD also manifests itself in an acute and chronic manner. Only a minority (30% to 40%) of animals developed lethal GVHD in our model. Those animals developing GVHD had a significantly (P < .0001) higher expression of TGF-beta in situ compared to the tolerant subpopulation. The differential expression of TGF-beta may represent an important mechanism of immune dysregulation associated with GVHD in CTA recipients.

Use of regression analysis and flow cytometry for determining levels of mixed semiallogeneic immune chimerism

It has been shown that tolerance or specific immunologic nonresponsiveness in various lymphohemopoietic transplant models can be associated with the development of mixed lymphoid chimerism. As a specific example, composite tissue (limb) allografts were studied as a model for vascularized bone marrow transplantation (VBMT) and it was demonstrated that development of stable cellular immune chimerism is associated with long-term allograft survival. Recently, studies were initiated using a new parental to hybrid VBMT model, but the detection of donor cells is complicated, due to the fact that they share one parental allotypic determinant. Therefore, regression analysis with a flow cytometric immunofluorescent staining assay was evaluated for the assessment of cellular lymphoid chimerism in donor parental to hybrid (P-->F1) lymphohemopoietic transplant models. Standard curves consisting of known mixed populations of parental donor (Lewis, LEW) and hybrid host F1 (Lew x BN, LBN) lymphocytes were established. Standard curves were analyzed by linear regression statistics and excellent coefficients of determination (r > .881) were obtained for all standard curves. A highly statistically significant (p < .016) linear relationship between level of donor cell chimerism (independent variable) and percent stained (dependent variable) was determined. The technique was then evaluated using the parental to hybrid VBMT model. Levels of donor LEW lymphoid chimerism in all VBMT LBN recipients were successfully assessed by regression analysis and inverse prediction using distinct recipient allodeterminant markers. In conclusion, this technique was proven to be reliable and accurate for the detection of of chimerism in parental to F1 lymphohemopoietic allograft models.

Chemotherapeutic treatment of malignant chordoma in children

PURPOSE

We describe the effect of multiagent chemotherapy for malignant chordoma. Previous reports of other patients with malignant chordoma treated with chemotherapy as well as other therapeutic interventions are reviewed.

PATIENTS AND METHODS

We describe a 19-month-old girl with unresectable cervical chordoma metastatic to the lungs at diagnosis treated with multiagent systemic chemotherapy. CNS disease was diagnosed after one course of therapy, and intrathecal chemotherapy was then administered.

CONCLUSIONS

Ifosfamide and doxorubicin were efficacious in a patient with advanced metastatic disease, producing significant disease regression. The addition of intrathecal or intraventricular therapy with hydrocortisone, ARA-C, and methotrexate was effective in controlling CNS disease due to chordoma. There was no apparent benefit from the use of actinomycin-D, cyclophosphamide and vincristine nor the combination of cisplatin and 5-fluorouracil or high-dose methotrexate.

Overview of a 10-year experience on methods and compositions for inducing site-specific immunosuppression with topical immunosuppressants

Methods and formulations have been successfully developed to bring about site-specific immune suppression of local T-cell-mediated immune responses involved in contact hypersensitivity, skin allograft rejection, and, putatively, autoimmune inflammatory conditions such as psoriasis. The induction of site-specific immune suppression results in reduced systemic pharmacology and toxicity. Certain formatulations have been devised that can effect dramatic transdermal drug delivery and systemic immunopharmacology. Local site-specific or systemic efficacy by transdermal delivery can be dependent upon carrier composition with respect to the hydrophilic/lipophilic nature of the solvent system, active principal solubilization, and concentration. Multiple classes of active immunosuppressive agents can be successfully combined to produce novel and extremely potent topical drugs. Specifically, either cyclosporine or rapamycin inhibit local inflammatory/immune responses by topical application to skin tissue in vivo. Rapamycin is particularly efficacious during the late local inflammatory/immune phase. Cyclosporine is particularly efficacious during the early local inflammatory-immune phase. Also, skin allograft survival may be prolonged via topical use of CyA, alone and in combination with other anti-inflammatory agents. This includes combined immunosuppressant and steroidal anti-inflammatory agents that can produce synergistic results. Systemic immunity in these instances is normal. Expression of MHC class I and MHC class II molecules is dramatically decreased in these CyA/steroid SITE-treated grafts. In summary, the induction of local immune suppression at the tissue site and focal responding immunocytes can result in surprising efficacy when used in conjunction with limited systemic administration, which could have significant immunologic and clinical ramifications.

Hemorrhagic subependymal giant cell astrocytoma

We describe the CT and MR findings in a patient diagnosed with tuberous sclerosis after presenting with a hemorrhagic subependymal giant cell astrocytoma (SEGCA). While these tumors are not uncommon in tuberous sclerosis, hemorrhage into them is extremely rare.

A rapid and sensitive cellular enzyme-linked immunoabsorbent assay (CELISA) for the detection and quantitation of antibodies against cell surface determinants. I. A comparison of cell fixation and storage techniques

A solid phase cellular ELISA was designed and evaluated for the detection of antibodies specific for cell surface determinants. It was hypothesized that certain fixation and freezing procedures would result in stabilization of cell structures for prevention of antigen diffusion and extraction during washing procedures. This would assure assay accuracy and convenient sample management. It was hypothesized that fixation with certain reagents prior to analysis would not alter antigenicity of antibody targeted epitopes. In order to improve the preservation of the cells following cell binding to the solid phase matrix while still retaining antigenicity and morphology, a series of fixatives and storage procedures were screened to determine which were best suited for CELISA. Methanol, washing buffer (WB), Hanks' balanced salt solution (HBSS), and 0.5% formalin in HBSS were examined by comparing their relative cell binding capacity and the subsequent cell morphology. In consideration of all variables, fixation in 0.5% formalin provided the best maintenance of cell antigenicity, morphology, binding, and was associated with consistent results. Cells used immediately after fixation and fixed cells used after storage at -80 degrees C for up to 12 months were compared to determine if long term storage affected antigenicity. Since frozen cells and fresh cells demonstrated statistically identical positive to negative ratios and consistency of antibody binding, it was determined that long term frozen storage of formalin-fixed cells did not adversely affect antibody binding capacity to cell surface determinants.

Venous sinus thrombosis as a cause of parenchymal and intraventricular hemorrhage in the full-term neonate

A case of parenchymal and intraventricular hemorrhage in a full-term neonate is reported. The underlying cause in our patient is thought to be related to cerebral sinovenous occlusive disease secondary to Protein C deficiency, a rare coagulopathy.

Congenital spondylolisthesis of the 6th cervical vertebra: CT findings

The CT demonstration of a case of congenital spondylolisthesis of the C6 vertebral body is reported. This entity includes bilateral bony defects in the pars interarticularis regions, deranged facet joints, as well as a midline bony cleft in the spinous process. This congenital deformity should be recognized and not mistaken for traumatic spondylolisthesis.

Mechanisms of prior blood transfusion-cyclosporine-induced tolerance: a potential role for immune-cellular chimerism

Skin allografts were not enhanced by prior conditioning of blood and CyA (5 or 10 mg/kg/d). However, when BM-CyA pretreatment was used, SA survival was significantly prolonged (CyA, 5 or 10 mg/kg/d). In examining differences between the BT-CyA and BM-CyA protocols, equivocal levels of donor microchimerism (1.5%) were found in the spleens of BT-CyA conditioned recipients at the time of transplantation (day 0). In contrast, highly significant levels of splenic donor chimerism (17.2%) developed at day 0 for the BM-CyA pretransplant recipients. Skin-allograft prolongation under the BM-CyA protocol implied that the effect may be linked to the existence of a donor-specific stem-cell population in the recipient animal.

Evaluation of the lumbar spine in patients with glycogen storage disease: CT demonstration of patterns of paraspinal muscle atrophy

CT studies of the lumbar spine were performed in 19 patients with glycogen storage disease. Nine of 10 patients with McArdle's disease and seven of nine patients with acid maltase deficiency demonstrated posterior paraspinal muscle atrophy out of proportion to their ages. In addition, the psoas muscles were spared in all 10 patients with McArdle's disease and were involved with atrophy in seven of the nine patients with acid maltase deficiency. We conclude that when patients with low back pain-or asymptomatic patients-demonstrate otherwise unexplained atrophy of the paraspinal muscles the diagnosis of glycogen storage disease should be considered. Furthermore, when the psoas muscles are spared, the specific diagnosis of McArdle's disease is suggested.

Development of stable mixed T cell chimerism and transplantation tolerance without immune modulation in recipients of vascularized bone marrow allografts

A consistent majority (62.5%) of immunologically unmodified rat recipients transplanted with vascularized hind-limb bone marrow allografts across a semiallogeneic transplant barrier developed tolerance with absence of graft-versus-host disease. A minority of recipients (37.5%) demonstrated lethal GVHD. Transplantation tolerance in the majority was associated with the induction of stable low-level mixed T cell chimerism, including donor CD5+, CD4+, and CD8+ lymphocytes. Chimeras were specifically immune nonresponsive to host alloantigenic determinants. These results emphasized a potentially important mechanism for low-level stable mixed lymphoid chimerism (SMLC) in tolerance induction, independent of immune suppressive effects due to irradiation or immunopharmacologic intervention. These vascularized bone marrow transplantation (VBMT) results may establish the experimental foundation for a novel approach to stem cell transfer and bone marrow transplantation.

Site-specific suppression of cell-mediated immunity by cyclosporine

In this study, it was demonstrated that site-specific suppression of T-cell-mediated immune responsiveness could indeed be achieved by topical application of cyclosporine. Evidence for site-specific immune suppression was obtained from a dual skin allograft model in rats. These animals were given an initial 10-d systemic treatment of CsA. Subsequently, one allograft was treated with topical CsA and the other was treated with the vehicle alone. Anti-inflammatory efficacy and prolonged skin allograft survival were observed both grossly and histopathologically in the presence of topically administered CsA, while contralateral vehicle-treated control grafts underwent vigorous rejection. Systemic lymphocyte DNA synthesis following Con-A and PHA stimulation was normal to elevated. Therefore, systemic T-cell-mediated immunity appeared unaffected or possibly activated even with concomitant topical CsA treatment. CsA levels were low systemically, and showed relative site-specificity in terms of tissue concentration. In conclusion, this study indicates that topical CsA is capable of locally suppressing a strong T-cell-mediated immune response after an initial short-term systemic dose of CsA. Furthermore, certain putative autoimmune and inflammatory diseases of the skin, such as psoriasis and eczematous dermatitis, which may share common mechanisms of action compared to skin allograft rejection should likewise benefit from topical CsA treatment.

The effects of testicular trauma on fertility in the Lewis rat and comparisons to isoimmunized recipients of syngeneic sperm

Adult male Lewis (LEW) rats were used to investigate the effects of unilateral testicular trauma on fertility. Comparisons were made between normal and experimental rats immunized with syngeneic sperm in Complete Freund's Adjuvant (CFA). Matings within the three groups yielded offspring to all normal males, no offspring to the immunized rats, and 27% (3/11) fertility in the trauma group (p less than 0.001). The contralateral testis demonstrated decreased volumes, various degrees of aspermatogenesis and smaller seminiferous tubular diameters, in both the trauma and immunized groups compared to the controls. Similar histopathologic findings of chronic granulomatous inflammation within contralateral testes in both the trauma and immunized groups suggested a common immune etiology for infertility via possible disruption of the blood-testis barrier.

Partial tolerance in rat renal allograft recipients following multiple blood transfusions and concomitant cyclosporine

Multiple prior administrations of donor-strain blood while under limited cyclosporine cover, consistently induce extensive rat renal allograft survival and transplantation tolerance. Yet it was hypothesized that some chronic rejection mechanisms were nevertheless operative since consistent but nonprogressive minor renal dysfunction was observed long-term. A histopathologic study on these putative tolerant rats was undertaken to test this hypothesis. Twenty long-term LEW recipients of BN renal allografts receiving the blood-CsA regimen were examined histopathologically at day 100 post-transplant. Sixteen control LEW recipients receiving only a BN renal allograft were studied acutely at day 7 posttransplant. The control recipients demonstrated a range of lesions consistent with previous studies on acute renal allograft rejection in the rat. However, tolerant recipients demonstrated mild-to-moderate lesions consistent with chronic mechanisms of rejection including the following: moderate focal interstitial mononuclear inflammatory cellular infiltration, with periglomerular and perivascular accumulation; occasional arteriolar luminal obliteration and glomerular atrophy; focal areas of moderate interstitial fibrosis; mild interstitial hemorrhage; mild-to-moderate tubular atrophy; and focal tubular necrosis. Previously our laboratory has documented that tissue-specific renal basement membrane antigens may be responsible for inciting this pattern of focal chronic interstitial inflammation. However, from the present histopathologic studies, it would appear likely that chronic rejection mechanisms in these recipients, which were defined as tolerant by immunologic criteria, involve both tissue-specific and MHC determinants. Therefore, induction of transplantation tolerance in these indefinite survivors is partial or incomplete.

Reconstructive allotransplantation: considerations regarding integumentary/musculoskeletal grafts, cyclosporine, wound coverage in thermal injury, and the immune response

With the advent of cyclosporine, a powerful and selective immunosuppressant, comes resurgence of a long-sought goal: to transplant modules of allointegumentary/musculoskeletal tissues or components thereof for the repair of peripheral tissue defects. Because these modules of integumentary and/or musculoskeletal tissue are actually composites of various tissues, they are also known as composite tissue allografts. The immediate goal of the studies reviewed herein is to lay the foundation in transplant immunobiology for the clinical exploitation of composite tissue allografts. The objective of these continuing studies is to induce permanent acceptance of composite tissue allografts. The value of such grafts lies in their potential for complete functional and cosmetic restoration in the surgical reconstruction of tissue after full-thickness burn injury. The initial results of basic experiments with cyclosporine are extremely encouraging in regard to the clinical potential for integumentary/musculoskeletal grafts in reconstructive allotransplantation.

Lethal cyclosporine associated toxicity in the rabbit: similar findings in two distant and independent transplant laboratories

A collaborative study was initiated between Basel and Irvine Laboratories named above in an attempt to characterize a unique and lethal gastrointestinal toxicity in rabbits associated with cyclosporine administration. Data from both laboratories were combined and analyzed. The rate of weight loss in CsA treated rabbits was found to be a significant linear function of the dose. In addition, animal survival decreased and showed a dose-dependent linear relationship to CsA use. Grossly, all of the animals presented with full stomachs, incompletely digested, dry, hard, rabbit chow. Histopathology could not provide any insight into the mechanisms of this gross finding and remain unclear. The complete similarity of clinical and histopathological results in distant independent laboratories confirms the specificity of this CsA associated toxicity in the rabbit.

Aneurysms and vascular malformations

Intracranial aneurysms and vascular malformations are frequently detected following intracranial hemorrhages. A CT scan is the most sensitive method of detecting acute subarachnoid, parenchymal, and intraventricular hemorrhages. Small aneurysms are inconsistently visualized on MR scans. Angiography remains the standard for complete and accurate depiction of patent aneurysms, as well as of arteriovenous and venous malformations that have not thrombosed. Giant and thrombosed aneurysms present as mass lesions and are frequently detected when MR is used as a screening examination. Often MRI characterizes these lesions better than CT or angiography. Patients with vascular malformations who have focal neurologic symptoms without hemorrhage are best evaluated with MRI. Patent vascular malformations demonstrating flow void and other flow-related phenomena are readily demonstrated. Occult vascular malformations, including thrombosed arteriovenous, venous, and cavernous malformations and telangiectasia, are also best detected by MRI and are not visible on angiography.

Histochemical properties of muscle allografts enhanced via cyclosporine

Until recently, the transplantation of skeletal muscle across a major histocompatibility barrier has proved difficult. However, with the advent of cyclosporine (CsA), it has become possible to achieve extended survival across such histocompatibility barriers. To date, very little is known about the histochemical, biochemical, immunological or contractile properties of long-term-surviving muscle allografts. Consequently, it was the focus of this study to histochemically examine muscle allografts prolonged with CsA and determine the cross-sectional area of fast glycolytic muscle fibers. Measurements of cross-sectional area were made because they are an important correlate to the amount of tension a muscle can generate. Animals were assigned randomly to one of three groups: control (normal) (n = 5), syngeneic (n = 4), and allogeneic (n = 4). Muscle allografts were performed by transplanting the gastrocnemius of an ACI rat (RT1a) hindlimb into the hindlimb of a Lewis rat (LEW;RT1(1]. The syngeneic model consisted of an ACI-to-ACI transplant. Animals in the allograft group were given CsA (8 mg/kg/day) until the time of sacrifice. At approximately 100 days following transplantation, both syngeneic and allogeneic muscles were removed from the recipient, and quickly frozen in isopentane cooled by liquid nitrogen. Muscle fibers were classified as slow-oxidative (SO), fast-oxidative-glycolytic (FOG), or fast-glycolytic (FG) based upon their staining for myofibrillar ATPase and NADH-dehydrogenase. From each muscle, the cross-sectional area of approximately 175 FG muscle fibers was determined. The fast-glycolytic muscle fibers of both the syngeneic and allogeneic grafts demonstrated a substantial decrease in cross-sectional area. The mean value (+/- SD) for the fibers of the allografted muscle was 1165 +/- 533 microns 2. The mean (+/- SD) fiber cross-sectional area for the fibers of the syngeneic muscle was 973 +/- 421 microns 2. These values contrast with a mean (+/- SD) value of 3552 +/- 601 microns 2 for fibers from age-matched control animals. The differences between the syngeneic and allogeneic muscles were not significant (P greater than 0.05). However, both exhibited significant (P less than 0.01) atrophy compared with the control muscle.

Serologic properties of the triple antibody-sandwich-lymphocyte-agglutination assay (TASLA)

Detailed studies concerning the serologic properties of the triple antibody-sandwich-lymphocyte-agglutination (TASLA) assay are described herin. The technique is a sensitive one based on sandwiching three layers of antibody onto the target cell. Two different test systems were utilized which included xeno- and allogeneic models. In the xenogeneic test system, rabbit-anti-DA lymphocyte xenosera served as the primary antibody sandwich layer. Goat-anti-rabbit and swine-anti-goat IgG served as the secondary and tertiary antibody sandwich layers, respectively. In the rat allogeneic test system, LEW-anti-BN rat lymphocyte allosera served as the primary antibody layer. Rabbit-anti-rat and goat-anti-rabbit IgG served as the secondary and tertiary antibody sandwich layers, respectively. Several different experiments were run with varying numbers of antibody sandwich layers, and differing concentrations within each layer. The lymphocyte agglutination reaction was then evaluated by regression analysis. Regardless of the number or concentration of antibody sandwich layers, it was found that the reaction could be functionally defined mathematically, by regression analysis. A secondary or tertiary antibody sandwich layer increased assay sensitivity. The level of lymphocyte agglutination was found to be both a linear function of the number of antibody sandwich layers and the concentration of each utilized. In addition, the serological properties of the TASLA assay were extended to the rat allogeneic test system and was again functionally defined mathematically by regression analysis.

Use of regression analysis and the complement-dependent cytotoxicity typing assay for predicting lymphoid chimerism

The complement-dependent cytotoxicity typing assay was studied for its accuracy in determining the presence of donor lymphocytes within standard chimeric donor/host cell combinations. Regression analysis of the data was utilized to evaluate the chimera assay. Excellent coefficients of determination (r2 greater than 0.90) were obtained for all standard curves, and a significant (P less than 0.001) linear relationship was established between percent cytotoxicity (dependent variable) and level of donor target cell chimerism (independent variable) for each regression equation. A highly significant (P less than 0.001) linear function was also established between percent cytotoxicity and concentration of donor target bone marrow cells. Regression coefficients (slopes) approached, but did not show complete unity (range; b = 0.86-0.95). Therefore, levels of cytotoxicity were not directly equivalent to levels of donor cell chimerism. A more accurate assessment of donor lymphoid chimerism would be provided by regression analysis of standard donor/host cell independent variables and inverse prediction. Significant estimates of peripheral donor lymphoid chimerism in putative mixed chimeric recipients were successfully made by this technique.

The development of humoral immunity to tissue-specific tubular basement membrane alloantigens after renal transplantation across the major histocompatibility barrier in rats immunomodulated with blood transfusions and cyclosporin

The development of a humoral immune response to the tubular basement membrane (TBM) alloantigen of Brown-Norway (BN) rat kidneys was studied after transplantation of BN rat kidneys into bilaterally nephrectomized Lewis (LEW) rats. The LEW rat recipients consisted of four groups receiving no form of immunosuppression, pretransplantation cyclosporin alone, or pretransplantation donor-specific or donor-nonspecific transfusions combined with cyclosporin. The latter two regimens induce indefinite allograft survival in the majority of recipients. Circulating antibody to collagenase-solubilized BN rat renal basement membrane (CS-BN-RBM) was present in all four groups of transplant recipients within 1 week after transplantation, and no significant differences in antibody levels were noted between rats receiving no immunosuppression (survival of 1-2 weeks) and the groups of rats who received various immunosuppressive regimens and survived longer. Circulating antibody to BN-CS-RBM continued to increase in quantity in the cyclosporin-treated group until the time of death (2-10 weeks post-transplantation). In the much longer lived combined transfusion and cyclosporin-treated groups, circulating antibody to BN-CS-RBM generally attained a maximum at approximately 2 to 4 months post-transplantation and then plateaued or decreased somewhat before the time of death (3-16 months post-transplantation). No correlation was found between quantity of circulating anti-BN-CS-RBM antibody and post-transplantation survival. Comparative study of the quantity of circulating antibody to BN-CS-RBM (the presumed nephritogenic antigen of experimental tubulointerstitial nephritis in the BN rat) in serum from transplant recipients as compared to serum from BN rats with severe experimental tubulointerstitial nephritis (TIN) (as induced by immunization with heterologous TBM antigens) demonstrated a greater quantity of potentially nephritogenic antibody circulating in transplant recipients than in BN rats with experimental TIN. Histologically, the transplanted kidneys in immunomodulated recipients demonstrated focal chronic interstitial inflammatory infiltrates with tubular atrophy and relative sparing of the glomeruli. The development of immune responses to tissue-specific alloantigens may become of clinical significance as graft-survival times are increased.

Lymphocyte chimerism in a full allogeneic composite tissue (rat-limb) allograft model prolonged with cyclosporine

LEW recipients of ACI vascularized hind limb allografts were analyzed for lymphoid chimerism by a complement-dependent cytotoxicity assay using antisera produced across this strain combination. In assessing the technique, two LEW recipients of sublethal irradiation (400 rad), ACI bone-marrow allografts, and CsA exhibited mixed lymphoid chimerism 23 days posttransplant. Short-term CsA-treated CTA recipients that were assayed at various times following transplantation and underwent subacute rejection did not demonstrate any significant mixed lymphoid chimerism. Long-term CsA-treated CTA recipients that were assayed at various times prior to 100 days posttransplant also did not demonstrate any significant mixed lymphoid chimerism. However, following extensive CTA survival (greater than 100 days) significant mixed donor-host lymphocyte chimerism became evident in the peripheral blood, and in one recipient a large quantity of donor bone marrow remained viable in the ACI limb allograft at necropsy (greater than 200 days posttransplant). The development of donor-host lymphocyte chimerism and a wasting syndrome that followed long-term CTA survival was suggestive of GVHD.