Distribution of lymphocytes of the alpha(E)beta(7) phenotype and E-cadherin in normal human urothelium and bladder carcinomas

The primary aim of this work was to survey normal urothelium and transitional cell carcinoma (TCC) for the presence of T lymphocytes expressing the intraepithelial, CD103(+) phenotype. This antigen defines the alpha(E)beta(7)-integrin. The adhesive counter-receptor for alpha(E)beta(7) is E-cadherin, which is down-regulated during cancer progression. The secondary aim was to determine the pattern of distribution of CD103(+) lymphocytes in relation to E-cadherin expression in bladder cancer. Cryostat sections of normal bladder and TCC were treated with antibodies specific for human CD103, CD3, CD8 and E-cadherin. Visualization was performed by immunoperoxidase or alkaline phosphatase development with light and confocal microscopy. Dual staining and serial sections were used to assess the relationship between these antigens. Four samples of normal bladder and 26 TCC samples were assessed. Occasional T lymphocytes (CD3(+)) were seen in normal urothelium and lamina propria. In the urothelium the majority of these T lymphocytes (71%) were also CD8(+) and of these 68% expressed the CD103 marker. In the lamina propria 62% of the T lymphocytes were CD8(+) and 56% of these expressed the CD103 marker. In carcinomas significantly greater numbers of CD103(+) T lymphocytes were present in the surrounding stroma rather than infiltrating the carcinomas (P = 0.0006). Of those T lymphocytes infiltrating the tumours, 71% were CD8(+) and of these 58% expressed CD103. In the surrounding stroma 52% of lymphocytes were CD8(+) and 82% of this subset expressed CD103. Infiltration by CD103(+) lymphocytes was not related to the intensity of E-cadherin expression. T lymphocytes of the CD103(+) phenotype are present in normal urothelium where they may play a role in immunosurveillance. Rather than infiltrating into carcinomas, these cells predominate in the surrounding stroma which could suggest a failure of immune function.

Active TGF-beta1 expression in kidney transplantation: a comparative study of cyclosporin-A (CyA) and tacrolimus (FK506)

Chronic rejection is a major cause of graft dysfunction following kidney transplantation. This fibroproliferative disease may be promoted by overproduction of transforming growth factor beta (TGF-beta). Previous studies have suggested that cyclosporin-A (CyA) might increase production of this growth factor. The current study was designed to measure the expression of TGF-beta in renal transplant biopsies from patients immunosuppressed with either CyA or tacrolimus. Paraffin-embedded renal biopsies were sectioned, dewaxed and incubated with primary antibody against active TGF-beta1 antibody. After washing, the sections were treated with secondary antibody conjugated with fluorescein isothiocyanate (FITC). In each case the sections were assessed by semi-quantitative scanning laser confocal microscopy. Biopsies from patients receiving CyA expressed significantly more active TGF-beta1 than biopsies from patients receiving tacrolimus (P < 0.0001, Mann-Whitney test). The increased level of active TGF-beta1 expression in renal biopsies of patients receiving CyA may indicate a mechanism of chronic rejection.

Dynamic expression of alternate splice forms of D-cbl during embryogenesis

The Cbl family of proteins act as E3 ubiquitin-protein ligases and have been associated with the down regulation of a variety of receptor tyrosine kinases. Cbl proteins associate with many different cell signalling molecules suggesting that they may have functions outside of the RING finger-mediated ubiquitin ligase activity. The Drosophila melanogaster cbl gene (D-cbl) encodes two splice forms (Oncogene 19 (2000) 3299). Here we report on the differential expression of these isoforms during Drosophila embryogenesis. Both isoforms are maternally expressed but the long isoform of D-cbl is also transiently expressed in the invaginating mesoderm and later is specifically expressed in neurons of the central nervous system (CNS). Cbl protein is shown to be localised to axons of the longitudinal connectives and commissures in the central nervous system.

Tubulitis after renal transplantation: demonstration of an association between CD103+ T cells, transforming growth factor beta1 expression and rejection grade

BACKGROUND

Tubulitis is a defining feature for the diagnosis and management of acute renal allograft rejection. Lymphocytes extracted from rejecting renal tissue are known to express the alphaEbeta7-integrin (CD103), a receptor for E-cadherin expressed on epithelial cells. In this study, expression of CD103 was examined in situ in tubulitis associated with acute rejection.

METHODS

Immuno-labeling detected CD8+ and CD103+ lymphocytes and E-cadherin on epithelial cells in cryostat sections from 34 diagnostic biopsy specimens and a limited number of transplant nephrectomies. CD8+ and CD103+ intratubular cells were enumerated as mean numbers per tubular crosssection and median values were compared between rejection grades as were median ratios of CD103+ to CD8+ cells. Active transforming growth factor (TGF) beta1 was quantified in paraffin sections by immunofluorescence and confocal microscopical analysis. A parallel in vitro study quantified CD103+ T cells after allospecific activation with and without exogenous TGFbeta1.

RESULTS

CD8+ T cells were present in tubules and tubular interstitium in acute rejection. CD103+ T cells were restricted exclusively to the tubules. The numbers of intratubular CD8+ and CD103+ cells and the ratio of intratubular CD103+ to CD8+ cells increased significantly with tubulitis score (P values 0.005, 0.009, and 0.02, respectively). TGFbeta1 expression was wide-spread in tubules also increasing significantly with tubulitis score (P=0.034). In chronic rejection, CD103+ T cells and TGFbeta1 were present within both tubules and interstitial cell populations. The in vitro study demonstrated that addition of TGFbeta1 to activated, alloantigen-specific T cells increased the proportion of CD8+ cells that also expressed CD103.

CONCLUSIONS

These data indicate that specific upregulation of the alphaEbeta7-integrin by activated, intratubular T cells in acute renal allograft rejection could be a consequence of exposure to high local concentrations of TGFbeta1. The capacity of CD103+ T cells to bind E-cadherin on tubular epithelial cells may be an important factor in the pathogenesis of specific tissue damage observed in acute renal allograft rejection.

Detection of cytomegalovirus (CMV) antigens in kidney biopsies and transplant nephrectomies as a marker for renal graft dysfunction

Chronic rejection accounts for the greatest loss of renal allografts. HLA mismatching has been minimised by organ allocation and new immunosuppressive drugs have been employed, but the average cadaveric graft survival still does not exceed 12 years. Though the aetiology is multifactorial, one contributory factor for this condition is cytomegalovirus (CMV). Detection of CMV in kidney biopsies and sera can diagnose and monitor this inflammatory event and define its role in chronic nephropathy. Twenty five biopsies taken at the time of transplantation, 10 biopsies for graft dysfunction and tissue blocks from 20 explanted kidney grafts were collected and investigated for CMV antigens by immunohistochemistry. Tissue samples were snap frozen and cryostat sections were incubated with monoclonal antibodies for CMV antigens followed by immunoperoxidase staining. In 12 out of 20 transplant nephrectomies CMV antigens were found. Only two of these patients had clinical CMV disease. Time 0 biopsies from CMV seronegative donors (n = 11) and CMV seropositive donors (n = 14) were negative for CMV antigens. The prevalence of CMV antigens in grafts lost due to chronic rejection was 60%. These antigens were not found within the time 0 biopsies, but were detected in 30% of biopsies taken at the time of clinical graft dysfunction. CMV appears to contribute to chronic rejection even without clinical disease.

A Drosophila analogue of v-Cbl is a dominant-negative oncoprotein in vivo

Cells rely on the ability to receive and interpret external signals to regulate growth, differentiation, and death. Positive transduction of these signals to the cytoplasm and nucleus has been extensively characterized, and genetic studies in Drosophila have made major contributions to the understanding of these pathways. Less well understood, but equally important, are the mechanisms underlying signal down-regulation. Here we report biochemical and genetic characterization of the Drosophila homologue of c-Cbl, a negative regulator of signal transduction with ubiquitin-protein ligase activity. A new isoform of D-Cbl, D-CblL, has been identified that contains SH3-binding and UBA domains previously reported to be absent. Genetic analysis demonstrates that Dv-cbl, analogous to the mammalian v-cbl oncogene, is a dominant negative mutation able to enhance signalling from the Drosophila Egfr and cooperate with activating mutations in the sevenless pathway to produce melanotic tumours. In addition, our data show genetic and biochemical links between D-Cbl and proteins involved in endocytosis and ubiquitination, suggesting that v-Cbl may exert its oncogenic effect by enhancing receptor signalling as a consequence of suppressing receptor endocytosis.

Intragraft proliferating T lymphocytes are associated with moderate acute pulmonary rejection

Acute allograft rejection is characterized by infiltration of the donor organ by host lymphoid cells, predominantly T lymphocytes. However, the site of proliferation and clonal expansion of alloreactive T lymphocytes is not well defined in man. A group of normal transbronchial biopsies (TBB, n=9) from clinically well lung transplant recipients was compared to TBB showing acute rejection (at least grade A2, n=9), using CD3- and Ki67-specific antibodies to double-label proliferating T lymphocytes. Few double-labeled lymphocytes were present in the normal biopsies (range, 0-3 cells). However, five of the rejection biopsies contained significant numbers of proliferating T lymphocytes (range, 19-47; Fisher's exact test; P=0.029). Furthermore, this positive group contained all three cases of grade A3 rejection in the study, as well as a case with persistent grade A2 rejection on follow-up biopsy. These data demonstrate that T lymphocytes do proliferate in transplanted human lungs; such proliferation is associated with more severe rejection.

Enhancement of survival of stored dopaminergic cells and promotion of graft survival by exposure of human fetal nigral tissue to glial cell line--derived neurotrophic factor in patients with Parkinson's disease. Report of two cases and technical considerations

The authors have studied the ability of glial cell line-derived neurotrophic factor (GDNF) to promote survival of human fetal dopaminergic tissue after a storage period of 6 days and subsequent implantation into the human putamen. The results indicate that GDNF promotes survival of stored dopaminergic cells. Cells stored without GDNF had a 30.1% decrease in survival time compared with those exposed to GDNF. Two patients with Parkinson's disease received bilateral putaminal implants of fetal dopaminergic cells exposed to GDNF for 6 days and showed enhancement of graft survival as assessed by positron emission tomography scanning. A mean increase of 107% in putaminal fluorodopa uptake from baseline values was observed 12 months postgrafting.

TGF-beta expression in renal transplant biopsies: a comparative study between cyclosporin-A and tacrolimus

BACKGROUND

Chronic rejection is a major cause of graft dysfunction after kidney transplantation. This fibroproliferative disease may be promoted by overproduction of transforming growth factor beta (TGF-beta). Previous studies have suggested that CsA might increase production of this growth factor. The current study was designed to measure the expression of TGF-beta(b) in renal transplant biopsy specimens from patients undergoing immunosuppressive therapy with either CsA or tacrolimus (FK506).

METHOD

Paraffin-embedded renal biopsy specimens were sectioned, dewaxed, and incubated with primary antibody against TGF-beta(b)1 latency-associated protein and active TGF-beta(b1). After washing, the sections were treated with secondary antibody conjugated with FITC. In each case, the sections were assessed by semi-quantitative scanning laser confocal microscopic method.

RESULTS

There was no significant difference in latent TGF-beta(b) expression between biopsy specimens from patients receiving CsA and patients receiving FK506. However, biopsy specimens from patients receiving CsA expressed significantly more active TGF-beta(b1) than biopsy specimens from patients receiving FK506 (P<0.0001, Mann-Whitney test).

DISCUSSION

The increased level of active TGF-beta1 expression in renal biopsy specimens of patients receiving CsA may indicate a mechanism of chronic rejection. However, these biopsies were performed to assess deranged renal function; therefore, the specimens may reflect events rather than differences in medication.

Renal allograft rejection: beta-chemokine involvement in the development of tubulitis

BACKGROUND

Tubulitis is a defining feature of renal allograft rejection. Graft dysfunction may result from damage inflicted on tubular epithelial cells by intratubular cytotoxic T lymphocytes. Graft cells are known to produce chemokines during acute rejection, but it is not known whether changes in expression of specific chemokines can influence the composition of the intratubular lymphocyte population. We examined expression of individual chemokines in biopsy sections showing different pathological rejection grades.

METHODS

Sections from Banff-graded transplant biopsies were examined for the presence of beta-chemokines (MCP-1, MIP-1alpha, MIP-1beta, and RANTES) by immunofluorescence and semiquantitative confocal laser scanning microscopy.

RESULTS

Beta-chemokines were expressed predominantly at the basolateral surface of tubular epithelial cells. Expression of MCP-1 and MIP-1beta was significantly higher in sections showing grade 2 rather than grade 1 acute rejection. RANTES and MIP-1alpha showed no significant variation in level of expression between rejection grades.

CONCLUSIONS

Beta-chemokines are expressed by tubular epithelial cells during acute rejection. Consistent expression of RANTES and MIP-1alpha suggests a general role in recruiting T lymphocytes. However, MCP-1 and MIP-1beta may play a more subtle role in recruitment of specific T-cell subsets, such as Th1 cells, during acute cellular rejection.

A simplified arteriovenous malformation model in sheep: feasibility study

BACKGROUND AND PURPOSE

Recently, a swine model of a cerebral arteriovenous malformation (AVM) has been developed that closely resembles a human AVM of the brain. The creation of such a model requires sophisticated neurointerventional techniques. The purpose of this study was to develop a simple and cost-effective AVM animal model that does not require additional endovascular techniques.

METHODS

A surgical anastomosis was created in seven sheep between the common carotid artery and the ipsilateral jugular vein, followed by ligation of the jugular vein above the anastomosis and of the proximal common carotid artery below the anastomosis. The anastomosis was created on the left side in four animals and on the right side in three. Cerebral angiography from the contralateral carotid artery was performed before and immediately after surgery to delineate the relevant cerebral vascular anatomy and to determine the direction of blood flow.

RESULTS

An angiographic appearance simulating an AVM was found in all the animals. The ramus anastomoticus and arteria anastomotica functioned as the feeding vessels to the rete mirabile, which represented the nidus in our model, and to the jugular vein, which represented the draining vein from the malformation. Extensive collateral flow through the rete mirabile into the distal segment of the external carotid artery above the ligature was observed angiographically, with retrograde flow through the surgical anastomosis into the jugular vein.

CONCLUSION

A simple surgically created experimental model for cerebral AVMs was developed in sheep without the need for additional complex endovascular catheter manipulations of intracranial branches. Such an animal model can substantially reduce the cost of research and training in the neurointerventional or radiosurgical management of AVMs.

Beta-chemokine expression and distribution in paraffin-embedded transplant renal biopsy sections: analysis by scanning laser confocal microscopy

Previous immunohistochemical and in situ hybridisation studies have shown that, in tubulitis associated with acute cellular rejection of human renal allografts, intratubular T cells proliferate and are fully activated in situ. In the immunohistochemical study reported here we have attempted to establish some understanding of the involvement of the beta-chemokines RANTES, MCP-1, MIP-1alpha and MIP-1beta in recruiting T cells to the intratubular site. Paraffin-embedded routine biopsy sections were treated for conventional indirect immunofluorescence to detect the selected chemokines. Scanning laser confocal microscopy was used to provide a measure of fluorescence intensity resulting from binding of FITC-labelled secondary antibody. Cells expressing chemokines could be identified and, within the limits of the staining method, it was possible to obtain a semi-quantitative assessment of individual chemokine activity at different points in biopsy sections by constructing a profile of fluorescence intensity. High concentrations of chemokines (especially RANTES, MIP-1beta and/or MIP-1alpha) were localised to the basolateral surface of tubular epithelial cells (TEC). MCP-1 was also consistently present but at a lower level than RANTES except in one case identified as BANFF category 3. There was diffuse distribution of chemokines in the interstitial matrix and low intensity fluorescence outlined some endothelial cells of peritubular venules and interstitial fibroblast-like cells. Our results suggest a mechanism for specific chemotactic recruitment of inflammatory cells by TEC-produced chemokines.

A c-Cbl yeast two hybrid screen reveals interactions with 14-3-3 isoforms and cytoskeletal components

The protein product of c-cbl proto-oncogene is known to interact with several proteins, including Grb2, Crk and PI3 kinase, and is thought to regulate signalling by many cell surface receptors. The precise function of c-Cbl in these pathways is not clear, although a genetic analysis in Caenorhabditis elegans suggests that c-Cbl is a negative regulator of the epidermal growth factor receptor. Here we describe a yeast two hybrid screen performed with c-Cbl in an attempt to further elucidate its role in signal transduction. The screen identified interactions involving c-Cbl and two 14-3-3 isoforms, cytokeratin 18, human unconventional myosin IC, and a recently identified SH3 domain containing protein, SH3 P17. We have used the yeast two hybrid assay to localise regions of c-Cbl required for its interaction with each of the proteins. Interaction with 14-3-3 is demonstrated in mammalian cell extracts.

Infestation of sheep dung by nematophagous fungi and implications for the control of free-living stages of gastro-intestinal nematodes

A field trial was conducted to assess the rate at which dung becomes infested by fungi which parasitise nematodes (nematophagous fungi) after deposition. Sheep dung was placed on field plots of bare ground, ryegrass (Lolium perenne), browntop (Agrostis capillaris) and white clover (Trifolium repens) in summer (February) and autumn (April), and subsamples were examined at intervals for the presence of nematophagous fungi. Nematophagous fungi occurred in 71% of 129 samples recovered in February and 57% of 58 samples recovered in April. Arthrobotrys oligospora, Monacrosporium candidum and Nematoctonus spp. were the most frequently isolated nematode-trapping fungi in both seasons. The endoparasitic nematophagous fungus Harposporium leptospira also occurred frequently in dung deposited in February, but not April. Fungi entered dung quickly, with 83% and 58% of dung samples containing nematophagous fungi at 3 days after deposition in February and April, respectively. The percentage of dung infested by nematophagous fungi on plots of bare ground, ryegrass, white clover and browntop was 76%, 75%, 61% and 55%, respectively. Results suggest that a number of species of nematophagous fungi are able to enter dung soon after deposition on a variety of types of ground cover.

Renal allograft rejection--in situ demonstration of cytotoxic intratubular cells

A nonisotopic in situ hybridization method to detect perforin mRNA was developed in cytospin preparations of IL-2-stimulated normal human lymphocytes and applied to formalin-fixed acutely rejected renal transplant material. Individual cells expressing perforin mRNA were localized in severely damaged tubular areas, and a number of these cells appeared to be located inside the tubular basement membrane in close association with tubular epithelial cells. Immunoperoxidase staining in acetone-fixed cryostat sections of acutely rejected kidney confirmed that a considerable proportion of infiltrating cells was CD8+; many of these were in an intratubular location. In addition, perforin protein was identified in individual cells in similar locations to perforin mRNA-positive cells. Again, some intratubular cells were identified. Our findings illustrate that these cells can be fully activated with definite cytotoxic potential. Previously we have demonstrated that T lymphocytes proliferate within the tubular compartment during tubulitis, a characteristic condition in acute renal allograft rejection, and that there is associated tubular epithelial cell proliferation. In this study we think that we have further clarified the consequences of invasion of tubules by lymphoid cells. Our in situ hybridization method in rapid and convenient and may be applied to archival material.

Poor knowledge and misunderstandings: perinatal data validity and work place change in midwifery

The purpose of this study was to improve the validity of data by empowering midwives to change inefficient work place practices. An easily accessible package was designed to enable midwives to compare how closely the information they recorded on the original perinatal morbidity statistics form corresponds with information recorded in the medical record: 37 hospitals validated 2197 medical records. The results showed that whilst most information was recorded reliably, some items caused problems for those completing the form. The findings encouraged midwives to change inefficient data collection practices. The project has improved the validity of data plus reduced the workloads of hospitals and the Perinatal Data Collection Unit with respect to queried items.