Structural Evolution of GaOx-Shell and Intermetallic Phases in Ga-Pt Supported Catalytically Active Liquid Metal Solutions

We present a comprehensive scale-bridging characterization approach for supported catalytically active liquid metal solutions (SCALMS) which combines lab-based X-ray microscopy, nano X-ray computed tomography (nano-CT), and correlative analytical transmission electron microscopy. SCALMS catalysts consist of low-melting alloy particles and have demonstrated high catalytic activity, selectivity, and long-term stability in propane dehydrogenation (PDH). We established an identical-location nano-CT workflow which allows us to reveal site-specific changes of Ga-Pt SCALMS before and after PDH. These observations are complemented by analytical transmission electron microscopy investigations providing information on the structure, chemical composition, and phase distribution of individual SCALMS particles. Key findings of this combined microscopic approach include (i) structural evolution of the SCALMS particles' GaOx shell, (ii) Pt segregation toward the oxide shell leading to the formation of Ga-Pt intermetallic phases, and (iii) cracking of the oxide shell accompanied by the release of liquid Ga-Pt toward the porous support.

[Long-term evaluation of low-dose-rate (LDR) brachytherapy in localized prostate cancer]

BACKGROUND AND OBJECTIVES

As a result of technical innovation, i.e., improvement of seed quality, implantation method, and dose calculation, it has been possible to continuously improve oncological results in the treatment of localized prostate cancer with low-dose-rate brachytherapy (LDR-BT). Randomized controlled trials have shown that there is no significant difference in oncological control between the use of radical prostatectomy and LDR-BT in patients with low-risk prostate cancer. The objective of this study was to investigate the oncological efficacy of LDR-BT.

MATERIALS AND METHODS

A retrospective multicenter analysis was conducted on 618 patients treated with LDR-BT as monotherapy, who received a dose of 145 Gy. We used iodine125 as the radioactive source. The analysis was conducted with follow-up data from two brachytherapy centers in Germany between 2004 and 2019. The primary endpoint was biochemical relapse-free survival (bRFS), whereby the Phoenix definition (PSA - nadir +2 ng/ml; PSA: prostate-specific antigen) was used to define biochemical relapse, i.e., therapeutic failure.

RESULTS

Median follow-up was 52 months (range 3-180 months). The bRFS across all risk groups was 87.87%. Oncological efficacy was significantly higher in patients with a Gleason score of 6 and 7a (p-value < 0.0001); however, there was no significant difference in bRFS between these two groups. Bilateral tumor infiltration or prostate volume had no significant influence on bRFS.

CONCLUSION

Our results show no difference in bRFS between Gleason score 6 and 7a.

Heterogeneity of circulating epithelial tumour cells from individual patients with respect to expression profiles and clonal growth (sphere formation) in breast cancer

Background

The detection of tumour cells circulating in the peripheral blood of patients with breast cancer is a sign that cells have been able to leave the primary tumour and survive in the circulation. However, in order to form metastases, they require additional properties such as the ability to adhere, self-renew, and grow. Here we present data that a variable fraction among the circulating tumour cells detected by the Maintrac^® approach expresses mRNA of the stem cell gene NANOG and of the adhesion molecule vimentin and is capable of forming tumour spheres, a property ascribed to tumour-initiating cells (TICs).

Patients and methods

Between ten and 50 circulating epithelial antigen-positive cells detected by the Maintrac approach were selected randomly from each of 20 patients with breast cancer before and after surgery and were isolated using automated capillary aspiration and deposited individually onto slides for expression profiling. In addition, the circulating tumour cells were cultured without isolation among the white blood cells from 39 patients with breast cancer in different stages of disease using culture methods favouring growth of epithelial cells.

Results

Although no epithelial cell adhesion molecule (EpCAM)-positive cells expressing stem cell genes or the adhesion molecule vimentin was detected before surgery, 10%–20% of the cells were found to be positive for mRNA of these genes after surgery.

Tumour spheres from circulating cells of 39 patients with different stages of breast cancer were grown without previous isolation in a fraction increasing with the aggressivity of the tumour.

Summary

Here we show that among the peripherally circulating tumour cells, a variable fraction is able to express stem cell and adhesion properties and can be grown into tumour spheres, a property ascribed to cells capable of initiating tumours and metastases.

Abstract P5-03-13: Detection of tumor initiating cells (TIC) among the peripherally circulating epithelial tumor cells from patients with breast cancer

Background: The detection of tumor cells circulating in the peripheral blood of patients with breast cancer is a sign that cells have been able to leave the primary tumor and survive in the circulation. However, in order to form metastases they require additional properties such as the ability to adhere, self renew and grow. Here we present data that a variable fraction among the circulating tumor cells detected by the maintrac® approach express mRNA of the stem cell gene nanog and of the adhesion molecule vimentin and are capable of forming tumor spheres a property ascribed to TIC.

Patients and methods: Between 10 to 50 circulating epithelial antigen positive cells detected by the maintrac® approach were selected randomly from each of 20 patients with breast cancer before and after surgery and isolated using automated capillary aspiration and deposited individually onto slides for expression profiling. In addition, the circulating tumor cells were cultured without isolation among the white blood cells from 5 patients with breast cancer in different stages of disease using culture methods favoring growth of epithelial cells.

Results: Although no EpCAM mRNA positive cells expressing stem cell genes or the adhesion molecule vimentin were detected before surgery, 10 to 20% of the cells were found to be positive for mRNA of these genes after surgery. Most surprisingly, it was possible to grow tumor spheres (Fig 1) from these circulating cells without previous isolation in all patients in a fraction comprising between 1% of the epithelial antigen positive cells in patients with newly diagnosed tumor up to 10% in a patient with advanced breast cancer.

Conclusion: We here show, that among the peripherally circulating tumor cells a variable fraction is able to express stem cell and adhesion properties and can be grown into tumor spheres, a property ascribed to cells capable of initiating tumors and metastases.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-13.

CD4 down-modulation by human immunodeficiency virus type 1 Nef correlates with the efficiency of viral replication and with CD4(+) T-cell depletion in human lymphoid tissue ex vivo

The human immunodeficiency virus type 1 (HIV-1) Nef protein is an important virulence factor. Nef has several functions, including down-modulation of CD4 and class I major histocompatibility complex cell surface expression, enhancement of virion infectivity, and stimulation of viral replication in peripheral blood mononuclear cells. Nef also increases HIV-1 replication in human lymphoid tissue (HLT) ex vivo. We analyzed recombinant and primary nef alleles with highly divergent activity in different in vitro assays to clarify which of these Nef activities are functionally linked. Our results demonstrate that Nef activity in CD4 down-regulation correlates significantly with the efficiency of HIV-1 replication and with the severity of CD4(+) T-cell depletion in HLT. In conclusion, HIV-1 Nef variants with increased activity in CD4 down-modulation would cause severe depletion of CD4(+) T cells in lymphoid tissues and accelerate AIDS progression.

[Laparoscopic liver donor nephrectomy. Personal experiences and review of the literature]

Despite improved success rates, the number of kidney transplantations in Germany in the last few years has stagnated, resulting in increasing waiting lists of patients on dialysis. In Germany, only 16.7% of kidney transplantations are living-donor nephrectomies, representing a relatively low rate compared to other countries (The Netherlands 28%, Sweden 35%). Since April 1998, we have performed ten retroperitoneoscopic living-donor nephrectomies (six left, four right side). The mean operating time was 216 min (155-290) with minimal blood loss. No intraoperative complications were observed. Warm ischemia time amounted to a mean of 4 min (2-7). The mean cold ischemia time was 165 min (76-290). Postoperative hospital stay of the donors was 6 days (4-10). All transplants functioned immediately; mean serum creatinine dropped from initially 8.0 mg/dl (5.3-11.5) on day 1 to 1.4 mg/dl (0.9-1.6) 3 months after surgery. This did not differ from previously operated open donor nephrectomies. An analysis of the literature included data of 4240 patients from 25 publications between 1980 and 2000 reporting on either open or laparoscopic living donor nephrectomies.

Modulation of different human immunodeficiency virus type 1 Nef functions during progression to AIDS

The human immunodeficiency virus type 1 (HIV-1) Nef protein has several independent functions that might contribute to efficient viral replication in vivo. Since HIV-1 adapts rapidly to its host environment, we investigated if different Nef properties are associated with disease progression. Functional analysis revealed that nef alleles obtained during late stages of infection did not efficiently downmodulate class I major histocompatibility complex but were highly active in the stimulation of viral replication. In comparison, functional activity in downregulation of CD4 and enhancement of HIV-1 infectivity were maintained or enhanced after AIDS progression. Our results demonstrate that various Nef activities are modulated during the course of HIV-1 infection to maintain high viral loads at different stages of disease progression. These findings suggest that all in vitro Nef functions investigated contribute to AIDS pathogenesis and indicate that nef variants with increased pathogenicity emerge in a significant number of HIV-1-infected individuals.

Disrupting surfaces of nef required for downregulation of CD4 and for enhancement of virion infectivity attenuates simian immunodeficiency virus replication in vivo

The multifunctional simian and human immunodeficiency virus (SIV and HIV) Nef proteins are important for virulence. We studied the importance of selected Nef functions using an SIV Nef with mutations in two regions that are required for CD4 downregulation. This Nef mutant is defective for downregulating CD4 and, in addition, for enhancing SIV infectivity and induction of SIV replication from infected quiescent peripheral blood mononuclear cells, but not for other known functions, including downregulation of class I major histocompatibility complex (MHC) cell surface expression. Replication of SIV containing this Nef variant in rhesus monkeys was attenuated early during infection. Subsequent increases in viral load coincided with selection of reversions and second-site compensatory changes in Nef. Our results indicate that the surfaces of Nef that mediate CD4 downregulation and the enhancement of virion infectivity are critical for SIV replication in vivo. Furthermore, these findings indicate that class I MHC downregulation by Nef is not sufficient for SIV virulence early in infection.

Simian immunodeficiency virus containing mutations in N-terminal tyrosine residues and in the PxxP motif in Nef replicates efficiently in rhesus macaques

SIVmac Nef contains two N-terminal tyrosines that were proposed to be part of an SH2-ligand domain and/or a tyrosine-based endocytosis signal and a putative SH3-ligand domain (P(104)xxP(107)). In the present study, we investigated the effects of combined mutations in these tyrosine and proline residues on simian immunodeficiency virus (SIV) Nef interactions with the cellular signal transduction and endocytic machinery. We found that mutation of Y(28)F, Y(39)F, P(104)A, and P(107)A (FFAA-Nef) had little effect on Nef functions such as the association with the cellular tyrosine kinase Src, downregulation of cell surface expression of CD4 and class I major histocompatibility complex, and enhancement of virion infectivity. However, mutations in the PxxP sequence reduced the ability of Nef to stimulate viral replication in primary lymphocytes. Three macaques infected with the SIVmac239 FFAA-Nef variant showed high viral loads during the acute phase of infection. Reversions in the mutated prolines were observed between 12 and 20 weeks postinfection. Importantly, reversion of A(107)-->P, which restored the ability of Nef to coprecipitate a 62-kDa phosphoprotein in in vitro kinase assays, did not precede the development of a high viral load. The Y(28)/Y(39)-->F(28)/F(39) substitutions did not revert. In conclusion, mutations in both the tyrosine residues and the putative SH3 ligand domain apparently do not disrupt major aspects of SIV Nef function in vivo.

Partial "repair" of defective NEF genes in a long-term nonprogressor with human immunodeficiency virus type 1 infection

A 36-bp deletion close to the 5' end of NEF that impaired Nef function was found in a long-term nonprogressor with human immunodeficiency virus type 1 (HIV-1) infection. Forms containing an adjacent duplication of 33 bp were also frequently observed. The duplication showed no homology to the deleted region but restored the overall length of the first variable loop of Nef. NEF alleles carrying the duplication were active in class I major histocompatibility complex (MHC-I) down-modulation and enhancement of virus infectivity. However, they showed little activity in CD4 down-regulation and were unable to stimulate viral replication in human peripheral blood mononuclear cells. Our study indicates that the enhancement of virion infectivity and the stimulation of HIV-1 replication in lymphocytes are distinct functions of Nef. Our findings also illustrate the capacity for repair of attenuating deletions in HIV-1 infection and suggest that a selective pressure for Nef-mediated MHC-I down-modulation and/or enhancement of virion infectivity exists.

The human immunodeficiency virus type 1 nef gene can to a large extent replace simian immunodeficiency virus nef in vivo

The nef gene of the pathogenic simian immunodeficiency virus (SIV) 239 clone was replaced with primary human immunodeficiency virus type 1 (HIV-1) nef alleles to investigate whether HIV-1 Nef can substitute for SIV Nef in vivo. Initially, two rhesus macaques were infected with the chimeric viruses (Nef-SHIVs). Most of the nef alleles obtained from both animals predicted intact open reading frames. Furthermore, forms containing upstream nucleotide substitutions that enhanced expression of the inserted gene became predominant. One animal maintained high viral loads and slowly progressed to immunodeficiency. nef long terminal repeat sequences amplified from this animal were used to generate a second generation of Nef-SHIVs. Two macaques, which were subsequently infected with a mixture of cloned chimeric viruses, showed high viral loads and progressed to fatal immunodeficiency. Five macaques received a single molecular clone, named SHIV-40K6. The SHIV-40K6 nef allele was active in CD4 and class I major histocompatibility complex downregulation and enhanced viral infectivity and replication. Notably, all of the macaques inoculated with SHIV-40K6 showed high levels of viral replication early in infection. During later stages, however, the course of infection was variable. Three animals maintained high viral loads and developed immunodeficiency. Of the remaining two macaques, which showed decreasing viral loads after the acute phase of infection, only one efficiently controlled viral replication and remained asymptomatic during 1.5 years of follow-up. The other animal showed an increasing viral load and developed signs of progressive infection during later stages. Our data demonstrate that HIV-1 nef can, to a large extent, functionally replace SIVmac nef in vivo.

Sequence variations in human immunodeficiency virus type 1 Nef are associated with different stages of disease

nef alleles derived from a large number of individuals infected with human immunodeficiency virus type 1 (HIV-1) were analyzed to investigate the frequency of disrupted nef genes and to elucidate whether specific amino acid substitutions in Nef are associated with different stages of disease. We confirm that deletions or gross abnormalities in nef are rarely present. However, a comparison of Nef consensus sequences derived from 41 long-term nonprogressors and from 50 individuals with progressive HIV-1 infection revealed that specific variations are associated with different stages of infection. Five amino acid variations in Nef (T15, N51, H102, L170, and E182) were more frequently observed among nonprogressors, while nine features (an additional N-terminal PxxP motif, A15, R39, T51, T157, C163, N169, Q170, and M182) were more frequently found in progressors. Strong correlations between the frequency of these variations in Nef and both the CD4(+)-cell count and the viral load were observed. Moreover, analysis of sequential samples obtained from two progressors revealed that several variations in Nef, which were more commonly observed in patients with low CD4(+)-T-cell counts, were detected only during or after progression to immunodeficiency. Our results indicate that sequence variations in Nef are associated with different stages of HIV-1 infection and suggest a link between nef gene function and the immune status of the infected individual.

The acidic region and conserved putative protein kinase C phosphorylation site in Nef are important for SIV replication in rhesus macaques

Variants of the pathogenic SIVmac239 clone with changes in Nef were analyzed to assess the functional relevance of two highly conserved regions in Nef in vitro and in vivo. Changes in a region with an acidic charge (Aci-Nef), or a potential protein kinase C phosphorylation site (PKC-Nef), impaired the ability of Nef to down-regulate CD4 and MHC class I surface expression and to alter CD3-initiated signal transduction in Jurkat T cells. The Aci-Nef, but not the PKC-Nef, associated with the previously described p65 phosphoprotein. SIV containing Aci-Nef, but not SIV containing PKC-Nef, showed reduced infectivity and replication in cell culture systems. One of two rhesus macaques infected with the PKC-Nef mutant virus showed rapid reversion and progressed to disease. In the second animal no reversions and nonprogressive infection was observed. In one of two macaques infected with the Aci-Nef variant, the mutations were stable during the first 40 weeks after infection. Thereafter, variants evolved in which up to six of the eight mutated positions in Nef were reverted and functional activity in vitro was partially restored. These changes occurred concomitantly with increasing viral load and disease progression. The second animal infected with the Aci-Nef variant showed no reversions and remained asymptomatic. Our study suggests that the acidic region and conserved PKC phosphorylation site in Nef are important for SIV replication in rhesus macaques and for several in vitro Nef functions. An almost wild-type activity in in vitro infectivity and replication assays seems insufficient to confer a full nef-positive phenotype in vivo.

Effect of the attenuating deletion and of sequence alterations evolving in vivo on simian immunodeficiency virus C8-Nef function

The simian immunodeficiency virus macC8 (SIVmacC8) variant has been used in a European Community Concerted Action project to study the efficacy and safety of live attenuated SIV vaccines in a large number of macaques. The attenuating deletion in the SIVmacC8 nef-long terminal repeat region encompasses only 12 bp and is "repaired" in a subset of infected animals. It is unknown whether C8-Nef retains some activity. Since it seems important to use only well-characterized deletion mutants in live attenuated vaccine studies, we analyzed the relevance of the deletion, and the duplications and point mutations selected in infected macaques for Nef function in vitro. The deletion, affecting amino acids 143 to 146 (DMYL), resulted in a dramatic decrease in Nef stability and function. The initial 12-bp duplication resulted in efficient Nef expression and an intermediate phenotype in infectivity assays, but it did not significantly restore the ability of Nef to stimulate viral replication and to downmodulate CD4 and class I major histocompatibility complex cell surface expression. The additional substitutions however, which subsequently evolved in vivo, gradually restored these Nef functions. It was noteworthy that coinfection experiments in the T-lymphoid 221 cell line revealed that even SIVmac nef variants carrying the original 12-bp deletion readily outgrew an otherwise isogenic virus containing a 182-bp deletion in the nef gene. Thus, although C8-Nef is unstable and severely impaired in in vitro assays, it maintains some residual activity to stimulate viral replication.

Selection of the R17Y substitution in SIVmac239 nef coincided with a dramatic increase in plasma viremia and rapid progression to death

Three rhesus macaques were infected with an SIVmac239 variant containing substitutions of 73/74PA-->ED and 204D-->R in Nef that disrupted the ability of Nef to downregulate CD4 surface expression. One of these animals, Mm8155, rapidly progressed to AIDS and died 21 weeks postinfection. During the final 5 weeks of infection, the levels of viral RNA and of p27 antigenemia were about 100-fold higher than usually observed in SIVmac239 infection. Postmortem examination revealed giant cell disease of the lymph nodes and the gastrointestinal tract, opportunistic infections, and a severe chronic enteritis. The majority of proviruses in spleen, kidney, and lymph nodes, and almost 100% of the viral RNA sequences, contained mutations of CGA-->TAT in codon 17 of nef, predicting a change of 17R-->Y. The appearance of this substitution, which has recently been shown to confer the phenotype of the acutely pathogenic SIVpbj14, coincided with the dramatic increase in viral load and rapid progression to fatal disease. In comparison, reversions of 204R-->D and changes of 72-74NED-->DKD, which restored the ability of Nef to downregulate CD4, were already selected earlier in infection. Similarly to SIVpbj14, virus reisolated at late time points from Mm8155 replicated efficiently in unstimulated monkey lymphocytes. The Y17 substitution was not detected in 14 additional SIVmac239-infected macaques at the time of AIDS-related death or in the two slowly progressing animals initially infected with the same Nef variant. Although infection of macaques with SIV is commonly used as an animal model for HIV-1 infection in humans, this is only the second example for the emergence of an acutely lethal SIVmac Nef variant.

Superior 3-year kidney graft function in patients with impaired pretransplant Th2 responses

In a prospective study of 80 patients, we investigated the association of kidney graft rejection with pretransplant CD4 helper/suppressor function, B cell responses, and in vitro cytokine secretion. A pokeweed mitogen-driven allogeneic coculture system was used to assess CD4 helper/suppressor function and T cell-dependent B cell responses. SAC I was used for T cell- and monocyte-independent stimulation of B cell cultures. B cell differentiation was assessed in a reverse hemolytic plaque assay. ELISAs were used to determine in vitro cytokine secretion. None of the 12 patients with pretransplant CD4 helper defects (< 10% helper activity) had acute rejection episodes in contrast to 32 of 68 (47%) patients with normal pretransplant CD4 helper function (P = 0.001). Patients with pretransplant CD4 helper defects exhibited better 3-year graft function than patients without CD4 helper defects (serum creatinine of functioning grafts: 1.2 +/- 0.1 mg/dl compared to 1.7 +/- 0.1 mg/dl, P < 0.05). Low pretransplant IL-10 responses (< 100 pg/ml; 14/80 patients) were significantly associated with a low incidence of acute rejection episodes (P < 0.01) and good 3-year graft function (P < 0.05). These data show that impaired pretransplant Th2 responses-CD4 help and IL-10 responses-predict a low risk of kidney graft rejection and good 3-year graft function, whereas Th1 (IL-2, IFN-gamma) and B cell/monocyte responses are not of predictive value.

[Mycophenolate mofetil (MMF) for prevention of kidney transplant rejection. A new immunosuppressive agent. International Mycophenolate Mofetil Study Group]

1493 patients were enrolled in 55 centers in Europe, Canada, Australia and the USA comparing the efficacy of mycophenolate mofetil (MMF) in daily doses of 2 and 3 g with placebo/azathioprine (PLA/AZA) for the prevention of acute rejection in renal transplant patients. Acute rejections and graft loss and death at 1 year were measured per trial and these data were combined and analyzed in a pooled fashion. The three pooled treatment groups were well balanced regarding demographic characteristics and cause of renal failure leading to transplantation. At one year the graft survival rate was 90.4% and 89.2% in the MMF 2 g and 3 g groups compared with 87.6% in the PLA/AZA-group. MMF 2 and 3 g were significantly better than PLA/AZA in reducing biopsy proven rejection at one year: 40.8% placebo/aza vs. 19.8% in the MMF 2 g group and 16.5% in the MMF 3 g group.

A placebo controlled study of mycophenolate mofetil used in combination with cyclosporine and corticosteroids for the prevention of acute rejection in renal allograft recipients: 1-year results. The European Mycophenolate Mofetil Cooperative Study Group

PURPOSE

We performed a randomized, double-blind, multicenter, placebo controlled study to compare the efficacy and safety of 2 oral doses of mycophenolate mofetil with placebo for prevention of acute rejection episodes following first or second cadaveric renal allograft transplantation.

MATERIALS AND METHODS

A total of 491 patients were enrolled in the study and randomly allocated to receive placebo (166), 1 gm. mycophenolate mofetil twice daily (165) or 1.5 gm. mycophenolate mofetil twice daily (160). Patients were given concomitant immunosuppression with cyclosporine and corticosteroids. Treatment with mycophenolate mofetil was initiated within 72 hours of transplantation and was continued for at least 1 year.

RESULTS

The percentages of patients who experienced biopsy proved rejection or withdrew early from the trial for any reason were significantly reduced with 2 gm. (30.3%) and 3 gm. (38.8%) mycophenolate mofetil compared to placebo (56.0%) (p < 0.001). The biopsy proved rejection rates of the placebo, and 2 gm. and 3 gm. mycophenolate mofetil treatment arms were 46.4, 17.6 and 13.8%, respectively. There were fewer patients in the 2 gm. (28.5%) and 3 gm. (24.4%) mycophenolate mofetil groups compared to the placebo (51.8%) group, who received full courses of corticosteroids or antilymphocyte agents for treatment of rejection episodes in the first 6 months after renal transplantation. There was a greater incidence of gastrointestinal adverse events, leukopenia and opportunistic events in the mycophenolate mofetil treatment groups.

CONCLUSIONS

Mycophenolate mofetil was shown to reduce significantly the number of patients who experienced biopsy proved rejection episodes or treatment failure during the first year after renal transplantation, and was well tolerated.

A comparative analysis of the interactions of the E6 proteins from cutaneous and genital papillomaviruses with p53 and E6AP in correlation to their transforming potential

Common necessity for all papillomaviruses is to induce DNA synthesis in quiescent cells. This is commonly achieved by the E7 gene product, which interferes with the function of members of the retinoblastoma family controlling transition from the G1-phase to the S-phase of the cell cycle. Uncontrolled entry into S-phase activates, however, negative growth control signals which have to be bypassed to achieve production of progeny viruses. In addition to inherent activities of the E7 protein, high risk genital types encode an E6 protein that overcomes p53-mediated G1-arrest and apoptosis in concert with the cellular factor E6AP by targeting p53 for the enhanced ubiquitin-dependent degradation. The key question, which of these functions of genital E6 and E7 proteins is responsible for the carcinogenic phenotype, is still not completely answered. In contrast to high risk genital types no immortalizing or transforming activities have been found for the E7 proteins of the high risk cutaneous HPV8 and 47. On the other hand the ability of the E6 protein to transform established rodent fibroblasts seems to be a property shared by high risk genital and cutaneous types. To examine the existence of a common E6-mediated transforming pathway for both virus groups we compared the properties of the cutaneous E6 proteins with already known functions of E6 proteins of genital viruses. For this we analyzed the E6 proteins of low nak and high risk cutaneous and genital papillomaviruses with respect to cell transformation, to their abilities to bind, degradate, and influence the activity of human p53, and to bind E6AP. The results of our study demonstrate a clear lack of interaction between the transforming E6 proteins of HPV1 and HPV8 and both cellular proteins p53 and E6AP. In contrast, we found E6AP-independent binding of HPV16 E6 and HPV6 E6 to p53, although both proteins were different in their transforming potential. Of all four proteins investigated, only HPV16 E6 was able to bind to p53 and E6AP and to induce degradation of the p53 protein in the reticulocyte system. When we investigated in frame deletion mutants of the E6 protein of HPV16 for their abilities to bind to p53 or E6AP, degradate, and inhibit the transactivation function of p53 and to transform rodent fibroblasts, no correlation between the different activities could be found. Mutants still able to bind p53 and E6AP lacked transforming ability and other mutants that were transformation-competent were deficient in p53 and E6AP bindings.

[The clinical significance of renal cell carcinoma in dialysis dependent patients in comparison with kidney transplant recipients]

The clinical relevance of de novo Renal Cell Cancer was compared in chronic hemodialysis patients and renal allograft recipients. Clinical course of these patients was followed for 15 years. 21 of 788 patients who underwent radical nephrectomy were suffering from renal insufficiency at the time of surgery. Evaluated data included clinical symptoms; tumor histology and clinical course. 19 patients received chronic hemodialysis treatment. 7 patients demonstrated stable function of the allograft. 92% of patients receiving hemodialysis treatment did not show metastasis and none died of renal cell carcinoma. On the contrary, 71% of patients who underwent renal transplantation showed advanced tumor disease or metastasis. 3 patients have died of RCC. Aggressive tumor growth of RCC requires close follow up in patients who received a renal allograft.

Pretransplant CD4 helper function and interleukin 10 response predict risk of acute kidney graft rejection

In a prospective study of 80 patients, we investigated the association of acute kidney graft rejection with pretransplant T helper/suppressor activity, B-cell responses, and in vitro cytokine secretion. Patients' CD4+ or CD8+ T cells were cocultured with control B cells and pokeweed mitogen for 6 days. SAC I was used for T cell- and monocyte-independent B-cell stimulation and pokeweed mitogen was used for T cell-dependent B-cell stimulation. B-cell differentiation was assessed in a reverse hemolytic plaque assay. Cytokine responses of T cells (interleukin [IL]-2, IL-10, gamma-interferon) and B cells/monocytes (IL-6, IL-8, tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor) were determined in culture supernatants using ELISA. Subsets of CD4+ T cells, CD8+ T cells, and B cells were assessed by flow cytometry. None of 12 patients with pretransplant CD4 helper defects (CD4 helper activity < 10%) had acute rejection episodes, in contrast to 32 of 68 (47%) patients with normal pretransplant CD4 helper function (P = 0.001). Patients with pretransplant CD4 helper defects also had better 1-year graft function than patients without CD4 helper defects (serum creatinine 1.2 +/- 0.1 mg/dl and 1.7 +/- 0.1 mg/dl, respectively, P < 0.05). Pretransplant IL-10 responses were significantly associated with the occurrence of acute rejection episodes (P = 0.001) and impaired 1-year graft function (P < 0.001). All 14 patients with low pretransplant IL-10 responses (< 100 pg/ml) had 1-year serum creatinine values of < 1.5 mg/dl. Pretransplant B-cell defects and B cell/monocyte-derived cytokine secretion were not related to the incidence of graft rejection or infectious complications. Pretransplant CD8 suppressor-effector (CD11b+), cell counts were significantly associated with the occurrence of infections (P < 0.05). These results show that pretransplant CD4 helper defects and low IL-10 responses predict a low risk of graft rejection, whereas Th1 (IL-2, gamma-interferon) and B-cell/monocyte responses are not of predictive value.