Induction Immunosuppressive Therapy With Everolimus and Low-Dose Tacrolimus Extended-Release Preserves Good Renal Function at 1 Year After Kidney Transplantation

BACKGROUND

Utilization of everolimus (EVR) has been increasing in recent years for patients undergoing renal transplantation to reduce calcineurin inhibitor (CNI) levels. However, an optimum regimen has yet to be established.

METHODS

We retrospectively examined 12 renal transplant recipients who underwent an induction immunosuppressive protocol; the protocol comprises 5 agents, including EVR plus low-dose tacrolimus extended-release (TAC-ER) treatment. We compared those findings from those of 14 patients who underwent a conventional protocol without EVR. Clinical outcome and pathologic changes were assessed by using protocol graft biopsy findings obtained at 3 months and 1 year after transplantation.

RESULTS

The estimated glomerular filtration rate was significantly higher for the EVR group at both 3 months and 1 year compared with the conventional group (P < .01 and P = .03, respectively). TAC-ER trough levels were also significantly lower at 3 months and 1 year (both, P < .01). Histologic findings of the 3-month protocol biopsy samples in the EVR group revealed 4 cases of borderline change and 2 of acute cellular-mediated rejection. The findings from the 1-year biopsy samples revealed 10 cases with normal findings with no evidence of CNI toxicity. Patients in the EVR group developed subclinical borderline change and acute cellular-mediated rejection after 3 months at a significantly higher rate than the conventional group (P = .02).

CONCLUSIONS

Use of the present therapeutic strategy successfully maintained the trough of each drug at a lower level, and it also kept renal function stable up to 1 year after transplantation.

Latent mesangial immunoglobulin A deposition in long-term functioning kidney does not correlate with disease progression and may exhibit fluctuating patterns

BACKGROUND

Latent mesangial immunoglobulin (Ig)A deposition in long-term functioning kidney does not correlate with disease progression and may exhibit fluctuating patterns Mesangial IgA deposition without urinary abnormalities (latent mesangial IgA deposition) is occasionally observed in non-episode biopsies of kidney allografts. However, the histologic features of latent IgA deposition have not been fully characterized.

METHODS

To better identify the clinicopathologic background of subclinical mesangial IgA deposition, we compared the clinical and histologic characteristics of long-term functioning kidney allografts with and without latent IgA deposition.

RESULTS

Among 29 patients with a posttransplant duration of >10 years, 37.9% exhibited latent mesangial IgA deposition. Biopsies indicated that renal function at the time of and 5 years before subclinical mesangial IgA deposition was generally similar. HLA-DR4 and HLA-Bw51 showed a nonsignificant trend to be more frequent in the IgA-positive group. Histologic investigation demonstrated no changes in disease scores based on the Banff 2009 classification between groups. Immunofluorescence revealed co-deposition of C3 at >1+ intensity in 72% IgA-positive patients. Immunohistochemical analysis revealed that IgA deposition per se did not cause notable increases in intraglomerular α-smooth muscle actin (SMA)-positive cells. One patient with subclinical IgA deposition demonstrated a waxing and waning pattern in the amount of IgA deposition.

CONCLUSION

This study suggests that subclinical IgA deposition in long-term functioning kidney allografts is not associated with progressive course in clinical and pathologic findings. Furthermore, the amount of subclinical IgA deposition may exhibit fluctuating patterns in some cases.

Clinicopathological study of expression of lymphatic vessels in renal allograft biopsy after treatment for acute rejection

BACKGROUND

Lymph vessel expression is related to inflammatory cell infiltration, around renal tubules in acute rejection episodes (ARE) of transplanted kidneys. However, there is little information on the lymph vessels after treatment of an ARE, particularly in relation to renal function and histological findings.

PATIENTS AND METHODS

We investigated 13 cases of ARE diagnosed by kidney transplant biopsy performed from 1997 to 2005 within 3 years of transplantation. Treatment of the ARE lead to an improved serum creatinine level in all cases. There was neither an ABO-incompatible nor an acute humoral rejection case. Lymphatic vessels in re-biopsies were examined using immunohistochemical staining with D2-40 antibody that detected lymphatic endothelium. Re-biopsy cases in which the baseline creatinine had increased by more than 20% despite treatment were considered the severe group; the others, as the stable group. The relation between lymphatic vessel density (LVD) and renal function was examined using Banff scores.

RESULTS

LVD was significantly higher in the severe than the stable group. The expression of lymph vessels versus the Banff score showed a direct relation: greater Banff scores showed higher expressions of lymph vessels.

CONCLUSIONS

The expression of lymph vessels in renal allograft specimens after treatment of an ARE was related to deterioration of renal function and inflammatory cell invasion. We plan a further examination of the relationship between the expression of lymph vessels and long-term prognosis.

Molecular basis distinguishing the DNA binding profile of Nrf2-Maf heterodimer from that of Maf homodimer

Nrf2-small Maf heterodimer activates the transcription of many cytoprotective genes through the antioxidant response element and serves as a key factor in xenobiotic and oxidative stress responses. Our surface plasmon resonance-microarray binding analysis revealed that both Nrf2-MafG heterodimer and MafG homodimer bind to the consensus Maf recognition element with high affinity but bind differentially to the suboptimal binding sequences degenerated from the consensus. We examined the molecular basis distinguishing the binding profile of Nrf2-MafG heterodimer from that of MafG homodimer and found that the Ala-502 residue in the basic region of Nrf2 is a critical determinant of its binding specificity. In Maf proteins, a tyrosine resides in the position corresponding to Ala-502 in Nrf2. We prepared a mutant Nrf2 molecule in which Ala-502 was replaced with tyrosine. In surface plasmon resonance-microarray analysis, heterodimer of Nrf2(A502Y) and MafG displayed a binding specificity similar to that of MafG homodimer. The target genes activated by mutant Nrf2(A502Y)-small Maf heterodimer were largely different, albeit with some overlap, from those activated by wild-type Nrf2-small Maf, indicating that the array of target genes regulated by Nrf2-small Maf heterodimer differs substantially from that regulated by Maf homodimer in vivo. These results suggest that the distinct DNA binding profile of Nrf2-Maf heterodimer is biologically significant for Nrf2 to function as a key regulator of cytoprotective genes. Our contention is supported that the differential DNA binding specificity between Maf homodimers and Nrf2-Maf heterodimers establishes the differential gene regulation by these dimer-forming transcription factors.

A chip-based miniaturized format for protein-expression profiling: the exploitation of comprehensively produced antibodies

Numerous antibodies have been developed and validated in recent years, and show promise for use in novel functional protein assays. Such assays would be an alternative to pre-existing comprehensive assays, such as DNA microarrays. Antibody microarrays are thought to represent those functional protein assays. While a variety of attempts have been made to apply DNA microarray technology to antibody microarrays, a fully optimized protocol has not been established. We have been conducting a project to comprehensively produce antibodies against mouse KIAA ("KI" stands for "Kazusa DNA Research Institute" and "AA" are reference characters) proteins. Using our library of antibodies, we established a novel antibody microarray format that utilizes surface plasmon resonance (SPR) technology. A label-free real-time measurement of protein expression in crude cell lysates was achieved by direct readout of the bindings using SPR. Further refinement of the antibody microarray format enabled us to detect a smaller quantity of target proteins in the lysate without the bulk effect. In this review, we first summarize available antibody array formats and then describe the above-mentioned format utilizing updated SPR technology.

Solution structure of a small-molecular ligand complexed with CAG trinucleotide repeat DNA

NMR structure of the first identified ligand, naphthyridine-azaquinolone (NA), complexed with the CAG-CAG triad is reported. The determined structure revealed the invasive ligands binding to the A-A mismatch and flanking G-C base pairs, causing the widowed cytosines to flip out from pi-stack. Hydrogen-bond pairs between NA and DNA, naphthyridine-guanine and azaquinolone-adenine, are well stacked in the right-handed DNA helix, showing structural mimicry of Watson-Crick base pairing. This is the first observation that the small molecular ligand induced the base flipping of the nucleotide base in the Watson-Crick base pair.

Retrospective Study of the Effects of Cyclosporine in Comparison With Azathioprine on Renal Transplant Recipients Infected With Hepatitis C Virus

A recent report noted that cyclosporine (CsA) inhibits replication of the hepatitis C virus (HCV) in vitro. Thus, CsA may be a superior immunosuppressant for renal transplant recipients infected with HCV. In the present retrospective study, we assessed whether CsA reduced the clinical impact of HCV infection among those patients. A total of 405 renal transplants were performed between 1973 and 2005, of whom we studied 189 who received CsA-based immunosuppression (CsA group) vs 108 who received an azathioprine-based regimen (AZA group). There were 44 HCVAb carriers and 145 noncarriers in the CsA group, and 41 carriers and 67 noncarriers in the AZA group. Our results showed that patient survival rate was significantly worse among HCVAb carriers than among noncarriers, as the overall survival rates were 82.9% and 90.9%, respectively, after 10 years and 71.5% and 85.7%, respectively, after 20 years (P = .0003). Patient survival rates were also significantly worse in HCVAb carriers than in noncarriers in both groups, which were 83.2% and 95.0%, respectively, after 10 years, and 74.7% and 88.8%, respectively, after 20 years (P = .0147) in the CsA group, and 82.9% and 83.6%, respectively, after 10 years and 70.7% and 80.6%, respectively, after 20 years (P = .0171) in the AZA group. Conversely, no significant difference was seen in patient survival rate for HCVAb carriers between the two groups (83.2% vs 82.9% at 10 years, and 74.7% vs 70.7% at 20 years, P = .8195). Our results confirmed that HCV infection has a negative impact on the long-term survival of renal transplant patients who receive either a CsA-based or an AZA-based regimen, suggesting that CsA does not have a positive impact on HCV carriers.

Predictive base substitution rules that determine the binding and transcriptional specificity of Maf recognition elements

Small Maf transcription factors possess a basic region-leucine zipper motif through which they form homodimers or heterodimers with CNC and Bach proteins. Different combinations of small Maf and CNC/Bach protein dimers bind to cis-acting DNA elements, collectively referred to as Maf-recognition elements (MAREs), to either activate or repress transcription. As MAREs defined by function are often divergent from the consensus sequence, we speculated that sequence variations in the MAREs form the basis for selective Maf:Maf or Maf:CNC dimer binding. To test this hypothesis, we analyzed the binding of Maf-containing dimers to variant sequences of the MARE using bacterially expressed MafG and Nrf2 proteins and a surface plasmon resonance-microarray imaging technique. We found that base substitutions in the MAREs actually determined their binding preference for different dimers. In fact, we were able to categorize MAREs into five groups: MafG homodimer-orientd MAREs (Groups I and II), ambivalent MAREs (Group III), MafG:Nrf2 heterodimer-orientd MAREs (Group IV), and silent MAREs (Group V). This study thus manifests that a clear set of rules pertaining to the cis-acting element determine whether a given MARE preferentially associates with MafG homodimer or with MafG:Nrf2 heterodimer.

SPR Imaging of Photo-Cross-Linked Small-Molecule Arrays on Gold

Identification of small-molecule ligands for a protein of interest can facilitate the analysis of the protein's functions in biological systems. Small-molecule microarrays have allowed for rapid detection of such ligand-protein interactions in a high-throughput manner, although a label on a protein is needed to observe these interactions. By combining SPR imaging technology with our recently developed photo-cross-linked small-molecule array platform, we developed a novel platform that allows in situ observation of interactions between photo-cross-linked small molecules on gold surfaces and nonlabeled proteins in solution. Interactions of estrogenic and androgenic substances with estrogen receptor alpha were observed using this platform.

Label-Free Detection of Proteins in Crude Cell Lysate with Antibody Arrays by a Surface Plasmon Resonance Imaging Technique

We established a label-free method of measuring proteins in crude cell lysate using antibody arrays and surface plasmon resonance (SPR) imaging. The refractivity of the running buffer was adjusted with that of the lysate to overcome the bulk effect. The chemistries of the fabricated arrays were investigated to reduce nonspecific adsorption on the array surface. We found that the hydrophilicity of the poly(ethylene glycol) moiety and lower electrostatic charge on the surface provided a specific measurement of antigen-antibody interaction. We validated the system by measuring the expression of eight proteins in the mouse brain and comparing the results to those by conventional Western blotting. The detection limit of the antibody array was approximately 30 ng/mL in crude cell lysate, on the same order as that of previous SPR research. The system enabled quick, label-free, and high-throughput analysis of abundant proteins with minimal sample volume ( approximately 200 muL). It is expected that our SPR antibody array will be applicable for direct protein expression profiling of cell lysate, as well as for cell phenotyping, food analysis, discovery of new biomarkers, and immunological disease diagnostics.

Sequential blood level monitoring of basiliximab during multisession plasmapheresis in a kidney transplant recipient

Basiliximab, a chimeric monoclonal antibody against the alpha chain of the interleukin-2 receptor (IL-2R) has been used in renal transplant patients. We monitored sequential blood concentrations of basiliximab in a patient who received a kidney transplant with basiliximab-based immunosuppression together with multiple sessions of plasmapheresis. A 34-year-old man received a living-related kidney transplant with induction immunosuppression including tacrolimus, mycophenolate, methylprednisolone, and basiliximab. Severe antibody-mediated acute rejection lead to a requirement for hemodialysis. Deoxyspergualin was administered for 10 days at a daily dose of 5 mg/kg combined with eight sessions of double filtration plasmapheresis (DFPP). After treatment, the serum creatinine returned to 0.95 mg/dL, and there were no major complications or infections. Sequential basiliximab blood levels of the patient were monitored following transplantation. The serum basiliximab concentration decreased by 72.4% after five consecutive DFPPs, and by 87.6% after eight DFPP sessions. The elimination rate of basiliximab (DeltaBLX) was 6.1% before DFPP, but increased over eight DFPPs to 20.5%. Serum basiliximab concentrations declined to 0.16 microg/mL on day 33, which is below the IL-2R saturation concentration (0.2 microg/mL). Multiple sessions of plasmapheresis using DFPP enhanced the elimination of serum basiliximab at an average elimination rate of 19.1%. In the patient reported on here, the serum basiliximab concentration fell to below the IL-2R saturation level (0.2 microg/mL) within 1 month of living-related kidney transplantation. We recommend that additional basiliximab infusions be considered for cases undergoing more than three plasmapheresis sessions.

Detection and Quantification of On-Chip Phosphorylated Peptides by Surface Plasmon Resonance Imaging Techniques Using a Phosphate Capture Molecule

We describe herein a detection and quantification system for on-chip phosphorylation of peptides by surface plasmon resonance (SPR) imaging techniques using a newly synthesized phosphate capture molecule (i.e., biotinylated zinc(II) complex). The biotinylated compound is a dinuclear zinc(II) complex that is suitable for accessing phosphate anions as a bridging ligand on the two zinc(II) ions. The compound was exposed on the peptide array and detected with streptavidin (SA) via a biotin-SA interaction by SPR imaging. In the conventional method using antibody, both anti-phosphoserine and anti-phosphotyrosine antibodies were required for phosphoserine and phosphotyrosine detection, respectively. Detection of the phosphate group by the zinc(II) complex, however, was independent of the phosphorylated amino acid residues. The calibration curve for the phosphorylation ratios was established with a calibration chip, on which phosphoserine-containing peptide probes were immobilized. The peptide probes, which were phosphorylated on the surface by protein kinase A, were detected and quantified by SPR imaging using the zinc(II) complex, SA, and anti-SA antibody. The reaction rate and the kinetics of on-chip phosphorylation were also evaluated with the peptide array. The phosphorylation ratio was saturated at approximately 20% in 2 h in this study.

Increased Expression of Renin in Chronic Allograft Nephropathy

BACKGROUND

Chronic allograft nephropathy (CAN) is the main cause of renal transplant failure in the first decade posttransplant. The precise pathogenetic mechanism for CAN is not completely understood. A possible role of renin-angiotensin system for CAN has been suggested through clinical observations that angiotensin-converting enzyme inhibition and angiotensin II receptor blockers prevent CAN.

METHODS

Distribution of renin-positive cells in allograft biopsy specimens was examined immunohistochemically in 23 renal transplant recipients diagnosed with CAN Biopsy specimens obtained from seven recipients with stable renal function were examined as controls. Histologic evaluation was performed based on the Banff 97 classification.

RESULTS

Renin-positive cells were found in the juxtaglomerular apparatus (JGA) adjoining the afferent arterioles in both groups. When the number of renin-positive cells in JGA was defined as a renin index, it was significantly higher in the CAN than the control group (P = .007). There was no significant difference in age, interval between transplantation and biopsy, and blood pressure between groups. Only a significantly higher serum creatinine was found in the CAN group.

CONCLUSIONS

The increased renin-positive cells in JGA suggest a significant role of the intrarenal renin-angiotensin system activation in the development of CAN.

Small-molecule ligand induces nucleotide flipping in (CAG)n trinucleotide repeats

DNA trinucleotide repeats, particularly CXG, are common within the human genome. However, expansion of trinucleotide repeats is associated with a number of disorders, including Huntington disease, spinobulbar muscular atrophy and spinocerebellar ataxia. In these cases, the repeat length is known to correlate with decreased age of onset and disease severity. Repeat expansion of (CAG)n, (CTG)n and (CGG)n trinucleotides may be related to the increased stability of alternative DNA hairpin structures consisting of CXG-CXG triads with X-X mismatches. Small-molecule ligands that selectively bound to CAG repeats could provide an important probe for determining repeat length and an important tool for investigating the in vivo repeat extension mechanism. Here we report that napthyridine-azaquinolone (NA, 1) is a ligand for CAG repeats and can be used as a diagnostic tool for determining repeat length. We show by NMR spectroscopy that binding of NA to CAG repeats induces the extrusion of a cytidine nucleotide from the DNA helix.

Point mutation detection with the sandwich method employing hydrogel nanospheres by the surface plasmon resonance imaging technique

We propose a surface modification procedure to construct DNA arrays for use in surface plasmon resonance (SPR) imaging studies for the highly sensitive detection of a K-ras point mutation, enhanced with hydrogel nanospheres. A homobifunctional alkane dithiol was adsorbed on Au film to obtain the thiol surface, and ethyleneglycol diglycidylether (EGDE) was reacted to insert the ethyleneglycol moiety, which can suppress nonspecific adsorption during SPR analysis. Then streptavidin (SA) was immobilized on EGDE using tosyl chloride activation. Biotinylated DNA ligands were bound to the SA surface via biotin-SA interaction to fabricate DNA arrays. In SPR analysis, the DNA analyte was exposed on the DNA array and hybridized with the immobilized DNA probes. Subsequently, the hydrogel nanospheres conjugated with DNA probes were bound to the DNA analytes in a sandwich configuration. The DNA-carrying nanospheres led to SPR signal enhancement and enabled us to discriminate a K-ras point mutation in the SPR difference image. The application of DNA-carrying hydrogel nanospheres for SPR imaging assays was a promising technique for high throughput and precise detection of point mutations.

A proof of the specificity of kanamycin-ribosomal RNA interaction with designed synthetic analogs and the antibacterial activity

The binding specificity of designed synthetic kanamycins with model RNA sequences (wild-type and point-mutated type) derived from the 16S ribosomal A-site was evaluated using surface plasmon resonance imaging. It was observed that kanamycins have nonspecific and multiple interactions with RNA hairpins and that the binding potency is not always proportional to the antimicrobial activity.

Combined Therapy of Deoxyspergualin and Plasmapheresis: A Useful Treatment for Antibody-Mediated Acute Rejection After Kidney Transplantation

Antibody-mediated acute rejection (AbAR) is one of the primary causes of graft impairment in kidney transplant recipients. Deoxyspergualin (DSG), which displays an antiproliferative action against antigen-stimulated B cells inhibiting antibody production, may be effective to rescue AbAR in combination with plasmapheresis by suppressing antibody production and elimination. In the present study, we report our experience with DSG/plasmapheresis therapy for the treatment of AbAR. Five kidney transplant patients experienced a steroid-resistant acute rejection requiring dialysis followed by an AbAR that was confirmed by biopsy and flow cytometry crossmatch (FCXM) results. DSG was administration at 3 mg/kg per day for 10 days with plasmapheresis reduce antidonor antibody. Treatment outcome, effectiveness, and adverse events were examined; in two cases sequential FCXM examinations were performed to evaluate antibody status. All five patients received DSG/plasmapheresis therapy. The number of plasmapheresis treatments ranged from 1 to 9 according to treatment outcomes. Four patients recovered graft function following treatment; whereas one showed no response to the treatment, and the graft was lost. No serious side effects or infections were observed during or after treatment. Monitoring of sequential FCXM correlated with the clinical course. AbAR shows a worse prognosis than cellular rejection. It is refractory to conventional antirejection therapy. In the present study, DSG/plasmapheresis therapy was effective in four of five patients (80%) with AbAR. It may be considered the first choice of treatment for cases of acute humoral rejection.

Evaluation of MafG interaction with Maf recognition element arrays by surface plasmon resonance imaging technique

Specific interactions between transcription factors and cis-acting DNA sequence motifs are primary events for the transcriptional regulation. Many regulatory elements appear to diverge from the most optimal recognition sequences. To evaluate affinities of a transcription factor to various suboptimal sequences, we have developed a new detection method based on the surface plasmon resonance (SPR) imaging technique. Transcription factor MafG and its recognition sequence MARE (Maf recognition elements) were adopted to evaluate the new method. We modified DNA immobilization procedure on to the gold chip, so that a double-stranded DNA array was successfully fabricated. We further found that a hydrophilic flexible spacer composed of the poly (ethylene glycol) moiety between DNA and alkanethiol self-assembled monolayers on the surface is effective for preventing nonspecific adsorption and facilitating specific binding of MafG. Multiple interaction profiles between MafG and six of MARE-related sequences were observed by the SPR imaging technique. The kinetic values obtained by SPR imaging showed very good correlation with those obtained from electrophoretic gel mobility shift assays, although absolute values were deviated from each other. These results demonstrate that the double-stranded DNA array fabricated with the modified multistep procedure can be applied for the comprehensive analysis of the transcription factor-DNA interaction.

Comparison of histopathological characteristics of allograft biopsy between responder and non-responder to antiproteinuric effect of angiotensin-converting enzyme inhibitor (ACEI)

Angiotensin-converting enzyme inhibitor (ACEI) has become recognized as agents that have renoprotective effects in the treatment of progressive renal diseases including post-transplant kidneys. Previously we demonstrated the safety and effectiveness of ACEI treatment on the hypertensive proteinuric post-transplant patients (N = 10) who had been followed up for 12 months. However, not all patients show good response in urinary protein reduction. We aimed to analyse the histopathological factor(s) affecting the responsiveness of proteinuria to ACEI treatment. Fourteen post-transplant patients with proteinuria who were treated with ACEI and underwent allograft biopsy were analysed. Eight patients showed 50% or more reduction in proteinuria (responder). The other 6 patients showed less (< 50%) reduction in proteinuria (non-responder). There was no difference in clinical characteristics (BP, renal function, donor age, recipient body mass index), dietary sodium or protein intake, and diuretic use between the two groups. As a histopathological characteristic, glomerular size in responder group was significantly larger than that in non-responder group. This suggests that the large glomerular size at least partly contributes to the responsiveness in urinary protein reduction to ACEI treatment in kidney allograft recipients with proteinuria.

Risk factors for graft loss in patients with recurrent IGA nephropathy after renal transplantation

BACKGROUND

The recurrence rate of IgA nephropathy (IgAN) in transplanted kidneys has been reported to be >50%. Although recurrent IgAN has a benign clinical course, recent data suggest that it leads to graft loss in a substantial number of patients.

METHODS

We performed a retrospective single-center analysis of 34 renal transplant recipients, with biopsy-proven IgAN as the cause of end-stage renal failure.

RESULTS

Renal allograft biopsies were performed in 30 patients, of whom 24 did and 6 did not have biopsy-confirmed recurrent transplant IgAN. Recurrent transplant IgAN was more often detected in men and at later timepoints after post-transplantation. Four patients with recurrent transplant IgAN progressed to graft failure. Progression to graft failure was associated with worsened renal function, higher systolic blood pressure, and the lack of presenation of angiotensin-converting enzyme inhibitors (ACEs) at the time of allograft biopsy. Immunologic factors such as frequency of acute rejection, HLA typing, and immunosuppression did not show a relation to recurrence or graft loss.

CONCLUSIONS

Recurrent transplant IgAN increased with long-term graft survival and risk factors for graft loss due to recurrent IgAN were similar to those among IgAN in native kidneys.

Green Fluorescent Detection of Fungal Colonization and Endopolygalacturonase Gene Expression in the Interaction of Alternaria citri with Citrus

ABSTRACT Alternaria citri, a postharvest pathogen, produces endopolygalacturonase (endoPG) and causes black rot on citrus fruit. We previously described that an endoPG-disrupted mutant of Alternaria citri was significantly reduced in its ability to macerate plant tissue and cause black rot symptoms on citrus. In order to investigate colonization of citrus fruit tissues by Alternaria citri, pTEFEGFP carrying a green fluorescent protein (GFP) gene was introduced into wild-type Alternaria citri and its endoPG-disrupted mutant (M60). Green fluorescence was observed in spores, germ tubes, appressoria, and infection hyphae of transformants G1 (derived from wild type) and GM4 (derived from M60). Hyphae of G1 but not GM4 vertically penetrated the peel, but the hyphae of both G1 and GM4 spread equally in the juice sac area of citrus fruit. Green fluorescence of Alternaria citri transformant EPG7 carrying a GFP gene under control of the endoPG gene promoter of Alternaria citri was induced by pectin in the peel during the infection stage, but repressed completely in the juice sac area, likely by carbon catabolite repression by sugars in the juice.

Chemically induced hairpin formation in DNA monolayers

A naphthyridine dimer that binds specifically to G-G mismatches has been used to induce hairpin formation in oligonucleotides immobilized onto chemically modified gold surfaces. Surface plasmon resonance (SPR) imaging measurements of DNA microarrays were used to demonstrate that binding of the naphthyridine dimer to G-G mismatches within the stem portion of an immobilized 42-mer oligonucleotide could be used to induce hairpin formation that prevented hybridization of DNA complementary to the loop sequence. In addition, the selectivity of the naphthyridine dimer for G-G mismatches was verified through SPR imaging measurements of the hybridization adsorption of an 11-mer oligonucleotide to a four-component DNA array of zero- and single-base mismatch sequences.

The differences between late graft loss group and long-term graft survival group in renal transplantation

In renal transplantation, the long-term graft survival rate has not been improved. Until now, the differences between late graft loss and long-term graft survival have still not been estimated thoroughly. We have attempted to define clinical risk factors and parameters for late graft loss by comparing the differences in these two groups. Data from the Osaka University Database were assessed on 156 renal allografts during a 7-yr period. Thirty-six patients comprised the late graft loss group (patients in this group had graft function without need for dialysis for more than 3 yr post-transplantation, afterwards lost the allograft: 'loss group'). One hundred and twenty patients comprised the long-term graft survival group (patients in this group had graft function without need for dialysis until 31 December 1999: 'survival group'). Various immunological and non-immunological parameters were included in an univariate regression analysis. This analysis showed that donor age (P < 0.01), HLA mismatch number (P < 0.01) and a repeat of acute rejection (P < 0.01) were significant factors. Serum creatinine levels at 3 months (P = 0.01), proteinuria at 1 yr (P < 0.01) and antihypertensive treatment at 2 yr (P = 0.03) after transplantation were predictive of the risk of late graft loss. CsA trough concentration at 3-6 months (P < 0.05) and body mass index increase at 1 yr (P = 0.046) were elevated in the loss group. These results from a single centre suggest that immunological as well as non-immunological factors are associated with the pathogenesis of late graft loss.

A case of tacrolimus nephrotoxicity appearing in a second renal transplantation patient

We experienced a case of a second renal transplantation patient. With the use of cyclosporin, he lost his first graft because of chronic rejection; with the use of tacrolimus, his second graft suffered from drug nephrotoxicity. On his second renal transplantation, his graft function deteriorated and required haemodialysis with the use of tacrolimus. Repeated biopsies did not reveal the typical characteristics of acute tacrolimus nephrotoxicity and acute rejection. His tacrolimus trough level was not high during the clinical course; however, by reducing tacrolimus dosage, his graft function eventually recovered to mild renal dysfunction. This observation was helpful for clinical diagnosis of the functional toxicity of tacrolimus. The case is interesting in considering the functional toxicity of tacrolimus and the difference between tacrolimus and cyclosporin in terms of immunosuppressive and nephrotoxic actions.

Clinicopathological evaluation in non-episode biopsies of renal transplant allograft

Histopathological findings in renal allograft with stable function remain unclear. We therefore performed non-episode biopsy in the long-surviving renal allograft to investigate the histopathological changes. Our data show that, although arteriolopathy is characteristic of drug-induced nephropathy, it is unrelated to dosage and concentration of cyclosporine or tacrolimus in non-episode biopsy. We evaluated therefore the clinicopathological findings of arteriolopathy in this study. Non-episode biopsy was defined as follows: as serum creatinine level lower than, 2.0 mg/dl and a urinary protein level lower than 500 mg/day. A total of 65 biopsy specimens were enrolled in this study as non-episode biopsy. Twenty-nine specimens revealed arteriolopathy. There were no statistically significant differences between arteriolopathy and dosage or concentration of cyclosporine or tacrolimus. Arteriolopathy in non-episode biopsy was related to time of biopsy, kidney age, hypertension, and hyperlipidemia, suggesting that it is important for graft survival to strictly control blood pressure and blood lipid level.

Factors influencing vertebral bone density after renal transplantation

To improve our understanding of the mechanisms underlying osteoporosis following renal transplantation, we compared bone mineral density (BMD) in 158 transplant recipients and in 293 patients undergoing maintenance hemodialysis with age- and sex-matched normal controls. Observations in graft recipients were made up to several years following transplantation. Dual-energy X-ray absorptiometry was used to measure BMD. Correlations with clinical variables including serum concentration of parathyroid hormone (PTH) and steroid therapy were evaluated. Lumbar BMD was lower in transplant patients than in dialysis patients at all ages, and continued to decrease with increasing interval posttransplant until the second year after transplantation. Persistent hyperparathyroidism and daily prednisolone dosage were both associated with decreased BMD. Age and creatinine clearance were independent long-term predictors of BMD by multiple regression analysis. Treatment of renal graft recipients with calcium and vitamin D supplements or calcitonin may be indicated in the early months after transplantation.

Arteriolopathy in non-episode biopsies of renal transplant allograft

PURPOSE

We have been performing protocol biopsies since 1995 to predict the outcome of renal allograft. However, histopathological findings in renal allograft with stable function remain unclear. For this reason, we performed non-episode biopsy on long-surviving renal allograft and investigated the histopathological changes. Among the several diseases seen in non-episode biopsies, arteriolopathy, such as drug-induced nephropathy, is one of the most frequent diseases. However, it is unrelated to the dosage and the concentration of cyclosporine or tacrolimus. Consequently, we evaluated the clinicopathological findings of arteriolopathy in this study in order to clarify whether cyclosporine (CsA) or tacrolimus (FK506) is responsible for these findings.

MATERIALS AND METHODS

We defined non-episode biopsy as a case with a serum creatinine level less than 2.0 mg/dL and containing less than 500 mg/dL of urinary protein. Final results showed that 71 cases were identified as non-episode biopsy. We then evaluated the histopathological findings and the clinical characteristics of these cases.

RESULTS

Thirty-two of the 71 non-episode biopsy specimens showed findings of arteriolopathy. The frequency and the severity of arteriolopathy are not concerned with dosage and concentration of CsA or FK506. The arteriolopathy seen in non-episode biopsy was related to the time of the biopsy and the kidney age. Arteriolopathy in nonepisode biopsy also had a relationship with hypertension, suggesting that it is important to strictly control blood pressure for graft survival.

A case of relapse of C-ANCA-associated glomerulonephritis in post-transplant patients

We experienced a case of relapse of proteinase 3-specific antineutrophil cytoplasmic autoantibody (C-ANCA)-associated rapid progressive glomerulonephritis (RPGN) in a patient after renal transplantation. A 19-yr-old man, who underwent a living donor kidney transplantation, presented a rapid renal function deterioration along with a sign of infection. Initially he was treated as acute rejection, but renal function did not improve. Renal biopsy revealed crescentic glomerulonephritis, and C-ANCA titer was 12 EU/mL, resulting in the diagnosis of C-ANCA-associated RPGN. He was treated with three consecutive methylprednisolone pulses twice in addition to the basal immunosuppressive medications (cyclosporine A and mizoribine), then his renal function improved to normal. Bearing the possibility of recurrence of glomerulonephritis in mind, we re-evaluated the nature and disease course of renal failure of original kidney. He experienced a rapid deterioration of renal function in 1992, and eventually CAPD was started in 1992. His serum in 1992 revealed high titer of C-ANCA (24 EU/mL), and renal biopsy performed in 1992 showed a crescentic glomerulonephritis. Taken together, we diagnosed this event as a relapse of C-ANCA-associated GN. Lessons from our experience are: 1) steroid pulse and high-dose corticosteroid therapy may be useful for the treatment of relapse of C-ANCA-associated GN patients after renal transplantation; 2) the possibility of a relapse of C-ANCA-associated GN following renal transplantation has to be kept in mind, especially when infection precedes the deterioration of allograft kidney function.

The impact of hepatitis C virus infection on liver disease in renal transplant recipients

To assess the prevalence of hepatitis C virus (HCV) infection in renal transplant recipients and its impact on posttransplant liver disease, the sera from 176 recipients who had been followed for 1-20 years (mean 8.3 years) were tested for HCV-specific antibody using enzyme immunoassay. HCV-specific antibody was detected in 53 patients (30.1%) including 2 patients also positive for hepatitis B surface antigen (HBsAg). Among 167 HBsAg-negative patients, the presence of HCV-specific antibody was associated with an increased incidence of chemically significant hepatitis (70.6% vs. 9.5% in anti-HCV-negative patients, P < 0.01). Hepatitis was more likely to be chronic in anti-HCV-positive patients than in anti-HCV-negative patients (P<0.05). Serious liver disease developed in 4 of 51 anti-HCV-positive, HBsAg-negative patients: liver failure causing death in 3 and hepatoma in 1. Liver biopsy specimens from anti-HCV-positive patients showed more aggressive histological lesions compared with those from anti-HCV-negative patients. We conclude that HCV infection is quite prevalent in our renal transplant recipients and plays a major role in posttransplant chronic liver disease.

Long-term graft survival rate of zero-mismatch kidney transplants for HLA-DRB1

The study of a two-locus association between HLA-B and -DRB 1 revealed a significant 43 linkage disequilibrium. Donor-recipient HLA-DRB1 was determined by these 43 linkages. Zero-mismatch for HLA-DRB1 had a significant effect on the graft survival rate in living related and cadaver transplants. The 5-year graft survival rate was 94% in the zero-mismatch group for HLA-DRB1, 96% for related transplants, 92% for cadaver cases, and 94% in HLA identical siblings. A statistically significant difference was found between the zero-mismatch group for HLA-DRB1 and mismatch groups for HLA-DRB1 or HLA-DR (P < 0.01). The zero-mismatch group for HLA-DRB1 had mismatches for HLA-A and/or HLA-B in 46 of 70 cases (66%). No significant differences in the rejection rate was observed between zero-mismatch and mismatch cases for HLA-A and/or -B in the zero-mismatch group for HLA-DRB1. In the second step, genotyping was conducted in 118 cases. The 5-year graft survival rate was 93% in the zero-mismatch group for HLA-DRB1 and 86% in mismatch group (not a significant difference). We concluded that zero-mismatch transplant for HLA-DRB1 had a better long-term graft survival rate regardless of HLA class I.

Chronic cyclosporin-induced nephropathy

AIMS

There is still no consensus about the prognostic influence of chronic nephropathy induced by low-dose maintenance therapy with cyclosporin. Our aim was to investigate the prognostic effect of cyclosporin nephropathy in Japanese renal transplant recipients.

MATERIAL

We retrospectively investigated the clinical records of 1,323 kidney transplant recipients who received cyclosporin at 65 institutions in Japan from 1982 to 1991.

METHOD

Renal biopsy was performed in 461 patients.

RESULTS

At 5 years and 9 years after transplantation, the patients who had cyclosporin nephropathy associated with immunological rejection, glomerulonephritis, or both showed a significantly worse prognosis than those with cyclosporin nephropathy alone (p < 0.01). There was no significant difference in the loss of renal function at 9 years after transplantation between patients showing no abnormalities and patients with cyclosporin nephropathy alone. Even when cyclosporin nephropathy was absent, the long-term prognosis was unfavorable in recipients with immunological rejection or glomerulonephritis.

CONCLUSIONS

These results suggest that cyclosporin nephropathy does not influence the prognosis of renal transplantation in patients on low-dose maintenance therapy with cyclosporin.

Comparative study of transurethral laser prostatectomy versus transurethral electroresection for benign prostatic hyperplasia

BACKGROUND

Transurethral resection of the prostate (TURP) is the gold standard treatment for benign prostatic hyperplasia (BPH). Recently, less invasive transurethral laser prostatectomy, such as visual laser ablation (VLAP) or interstitial laser coagulation (ILCP), have been developed. Herein, we investigated the efficacy of VLAP and ILCP compared to TURP.

METHODS

A total of 80 patients with BPH were treated: 20 patients by VLAP, 30 patients by ILCP and 30 patients by TURP. All patients were followed up for 12 months after their operations. Treatment outcomes were evaluated by four different criteria: (i) the International Prostatic Symptom Score (I-PSS), (ii) the maximum flow rate (Qmax), (iii) postvoided residual urine volume before treatment and one, three, six and 12 months after treatment, and (iv) prostatic volume before operation and three and six months postoperatively.

RESULTS

The I-PSS, Qmax and residual urine volume were significantly improved compared to baseline levels and the improvement continued for 12 months in the three groups: for I-PSS (P<0.001 in the VLAP group and P<0.0001 in the ILCP and TURP groups), Qmax (P<0.001 in the VLAP and ILCP groups, and P<0.0001 in the TURP group), residual urine volume (P<0.01 in the VLAP group and P<0.0001 in the ILCP and TURP groups). Significant reduction of the prostatic volume was recorded only in the ILCP and TURP groups (P<0.001).

CONCLUSION

Visual laser ablation and ILCP can be good alternative treatments for BPH. Visual laser ablation provides good outcomes in patients with small-sized BPH and with risk factors such as heart disease or anticoagulation therapy.

A clinicopathological study of IgA nephropathy in renal transplant recipients: beneficial effect of angiotensin-converting enzyme inhibitor

BACKGROUND

Prolonging the survival of transplant kidneys is a major task of modern nephrology. It has recently been shown that deteriorating renal function and substantial graft loss were observed in 55% of renal allograft recipients with recurrent IgA nephropathy (IgAN) at long-term follow-up. To gain a useful insight into the therapeutic approach towards protecting allograft kidneys from deteriorating graft function, we compared the histological characteristics of post-transplant IgAN to primary IgAN and investigated the effects of an ACE inhibitor.

METHODS

Twenty-one patients with post-transplant IgAN and 63 patients with primary IgAN were included in the histopathological study. The effectiveness of angiotensin-converting enzyme (ACE) inhibitor treatment in post-transplant IgAN was also studied in 10 patients.

RESULTS

The prevalence of glomeruli with adhesions and/or cellular crescents in primary IgAN was significantly greater than in post-transplant IgAN (P<0.05), but the proportion of glomeruli with segmental sclerosis was similar in both groups. The rate of global obsolescence, and the degree of interstitial fibrosis in post-transplant IgAN were significantly greater than in primary IgAN (P<0.05). The degree of glomerular obsolescence and the severity of interstitial fibrosis correlated with the severity of glomerular lesion in primary IgAN, but not in post-transplant IgAN. In primary IgAN, glomerular diameter significantly correlated with the proportions of glomerular obsolescence, but not in post-transplant IgAN, suggesting that allograft kidneys may be in a hyperfiltration state. Both the blood pressure and the urinary protein excretion significantly improved after ACE-inhibitor treatment (P<0.001).

CONCLUSION

In post-transplant IgAN, histopathological lesions indicative of acute inflammatory insults were suppressed, and glomerular hypertrophy, which may relate to haemodynamic burden such as hyperfiltration, was prominent. Preliminary study of ACE-inhibitor treatment in 10 patients showed favourable effects. A future long-term follow-up study is required to establish the effectiveness of ACE inhibitors in treatment of post-transplant IgAN.

Cloning of cDNA encoding NtEPc, a marker protein for the embryogenic dedifferentiation of immature tobacco pollen grains cultured in vitro

We partially purified three Nicotiana tabacum L. embryogenic pollen-abundant phosphoproteins (NtEPa to c) which appeared in the cells undergoing a dedifferentiation process from immature pollen grains to embryogenic cells, caused by glutamine-deficiency in vitro. All the NtEPs had a highly conserved N-terminal amino acid sequence. Using degenerate oligonucleotide probes designed from the amino acid sequences, the cDNA for NtEPc was isolated from a cDNA library of pollen cultured in glutamine-free medium The cDNA sequence showed moderate homology with several type-1 copper-binding glycoproteins and with a kind of early nodulin though its function could not be predicted. Expression analysis revealed that the level of mRNA for NtEPc was high during the dedifferentiation and also in the very early period of pollen embryogenesis but it was low in the developmental process of microspores/pollen in anthers, in the in vitro maturation process and both in the stational and logarithmic growth phases of tobacco BY-2 cells. Furthermore, an acidic medium pH, which promoted the induction of dedifferentiation increased the level of mRNA for NtEPc, whereas the presence of 6-benzylaminopurine, which inhibited it, decreased the level. These results suggest that the expression of NtEPc gene is correlated with the dedifferentiation but not with pollen development or cell division.