Clinical characteristics and outcomes of adenovirus infection of the urinary tract after renal transplantation.

BACKGROUND: Urinary tract infection caused by human adenovirus (HAdV) after renal transplantation (RT) results in graft loss because of concomitant nephropathy and acute rejection and may result in death because of systemic dissemination. METHODS: We assessed the time period between RT and disease onset, symptoms, treatment details, disease duration, renal graft function, outcomes, and complications. RESULTS: HAdV infection of the urinary tract occurred in 8 of 170 renal transplant recipients. Symptoms were macrohematuria in all 8 patients, dysuria in 7, and fever in 5. The median period from RT to disease onset was 367 (range, 7-1763) days, and the median disease duration was 15 (range, 8-42) days. The mean serum creatinine (sCr) level prior to onset was 1.35 ± 0.48 mg/dL and the mean maximum sCr level during disease was 2.34 ± 1.95 mg/dL. These values were increased by ≥25% in 5 patients. The mean sCr levels when symptoms resolved was 1.54 ± 0.67 mg/dL, and no significant difference was seen before, during, or after disease onset (P = 0.069). Two patients were diagnosed with HAdV viremia and 1 with acute tubulointerstitial nephritis revealed on biopsy. In addition to a reduction in immunosuppressant dosage, 2 patients received gammaglobulins and 5 received ganciclovir. CONCLUSION: Symptoms of all patients were alleviated, although some patients developed nephritis or viremia. Hence, the possibility of exacerbation should always be considered. Adequate follow-up observation should be conducted, and diligent and aggressive therapeutic intervention is required to prevent the condition from worsening.

Effects of immunosuppressants on the progression of hepatitis C in hepatitis C virus-positive renal transplantation and the usefulness of interferon therapy.

OBJECTIVE: The purpose of this study was to analyze the effects of immunosuppressants on hepatitis C virus (HCV) replication to establish optimal immunosuppressive therapy in HCV-positive renal transplantation. MATERIALS AND METHODS: Cyclosporine (CsA), tacrolimus (Tac), mycophenolate acid (MPA), the active metabolite of mycophenolate mofetil (MMF), and methylprednisolone (MP) were administered to HCV replicon cells alone or in combination with interferon (IFN). HCV RNA was quantitatively determined. Of our 2064 recipients of renal transplantations between 1980 and 2005, 153 were HCV-positive. We analyzed changes in hepatic function and the efficacy of IFN therapy in these patients. RESULTS: Only CsA strongly inhibited the growth of HCV RNA (13.1% at 1.0 microg/mL). MPA enhanced the inhibition of the growth of HCV RNA in the presence of IFN. Tac and MP reduced, rather than enhanced, the efficacy of IFN. Progression to chronic hepatitis occurred in a significantly smaller number of patients in the CsA than the Tac group (6 vs 19; P = .04). Serum alanine aminotransferase (ALT) levels were comparable pretransplantation and posttransplantation in the CsA group (24.8 +/- 20.5 vs 28.9 +/- 28.3 IU/L, respectively, while a significant elevation was noted in the Tac group (22.2 +/- 21.5 vs 32.6 +/- 30.8 IU/L, respectively; P = .024). Two of 4 patients who underwent combination therapy with IFN and ribavirin during treatment with CsA and MMF obtained an HCV-negative status for over 24 weeks. CONCLUSIONS: CsA effectively prevents the progression of chronic hepatitis in HCV-positive renal transplant patients. A greater response rate can be expected by concurrent administration of CsA and MMF under IFN therapy.

Hand-assisted laparoscopic splenectomy in ABO-incompatible kidney transplant recipients.

OBJECTIVE: We perform living-related ABO-incompatible kidney transplantations to alleviate the organ shortage in our country. Splenectomy has been performed routinely in these recipients, although its clinical significance remains controversial. In this study, we have reported our experience with a hand-assisted laparoscopic splenectomy (HALS) technique. METHODS: Between April 2000 and December 2006, 50 patients (23 males) underwent ABO-incompatible kidney transplantation with HALS. The mean age and weight of the recipients were 44 +/- 13 years and 56 +/- 12 kg, respectively. All patients underwent preoperative plasmapheresis to reduce isoagglutinin (A and/or B antibody). In 6/50 patients, a hand-assisted device was placed through a peritoneal window in the right lower abdominal skin incision for kidney engraftment. In the remaining 44 patients, a 6-cm upper midline or periumbilical midline incision was made for the hand-assisted device in the lateral position. RESULTS: An ABO-incompatible procedure was completed successfully in all cases. The average HALS time was 118 +/- 42 minutes, with an average pneumoperitoneum time of 79 +/- 40 minutes and average blood loss of 48 +/- 81 g. There were two conversions to open splenectomy because of intraoperative bleeding and suspected pneumothorax. Two other cases required relaparotomy because of hematoma and perforation of the ileum. Successfully operations were achieved through the previous periumbilical incision. CONCLUSIONS: Although meticulous, rigorous surgical technique is essential, HALS is safe and feasible for recipients of ABO-incompatible grafts with tissue weakness and a bleeding tendency because of renal failure and preoperative plasmapheresis.

Prevention of Late-Onset Cytomegalovirus Infection and Disease in Donor-Positive/Recipient-Negative Kidney Transplant Recipients Using Low-Dose Valganciclovir.

BACKGROUND: The main challenge with cytomegalovirus (CMV) prophylaxis in IgG donor-positive/recipient-negative (D+/R-) kidney transplant recipients is late-onset CMV disease. We evaluated a novel protocol for the prevention of late-onset CMV infection and disease in D+/R- organ recipients. METHODS: Our prospective, observational, cohort study included 100 adult kidney transplant recipients. Prophylaxis with low-dose valganciclovir (450 mg/d, 3 times a week for 6 months) was administered to D+/R- recipients. Risk factors for CMV infection and disease were identified. Renal function and the outcomes of CMV infection and disease were compared between D+/R- (n = 15) and recipient-positive (R+; n = 81) organ recipients. RESULTS: D+/R- recipients showed significant independent risk factors with high hazard ratios for CMV infection (2.04) and disease (10.3). The proportion of CMV infection in D+/R- and R+ recipients was 80% and 46% (P = .023), and that of CMV disease was 33% and 6.2% (P = .008), repectively. D+/R- recipients developed CMV infection and disease within 6 months after transplantation. However, both CMV infection- and disease-free survival rates beyond 1 year post-transplantation defined as late-onset were stable in D+/R- recipients. Moreover, serum creatinine levels at 1 year post-transplantation were comparable between D+/R- and R+ recipients (1.45 ± 0.71 vs 1.16 ± 0.35 mg/dL, P = .26). CONCLUSION: Our novel protocol prevented late-onset CMV infection and disease beyond 1 year post-transplantation in D+/R- recipients.

Steroid Withdrawal Using Everolimus in ABO-Incompatible Kidney Transplant Recipients With Post-Transplant Diabetes Mellitus.

BACKGROUND: The effectiveness of everolimus (EVR) for ABO-incompatible (ABOi) kidney transplantation is unknown. We evaluated outcomes of conversion from steroid to EVR in ABOi kidney transplant recipients. METHODS: We performed a retrospective observational cohort study of 33 de novo consecutive adult ABOi living donor kidney transplant recipients. Desensitization was performed using 0 to 4 sessions of plasmapheresis and 1 to 2 doses of 100 mg rituximab according to the anti-A/B antibody titer. ABOi recipients were administered a combination of tacrolimus, mycophenolate mofetil, and methylprednisolone. Diabetic patients were converted from methylprednisolone to EVR at 1 to 15 months post-transplantation to prevent diabetes progression. Graft outcomes, hemoglobin A1c (HbA1c) levels, and cytomegalovirus infection rates were compared between the EVR (n = 11) and steroid (n = 22) groups. RESULTS: Mean postoperative duration was 814 and 727 days in the EVR and steroid groups, respectively (P = .65). Between the 2 groups, graft survival rate (100% vs 95.5%, P > .99), acute rejection rate (9.1% vs 18.2%, P = .64), and serum creatinine levels (1.46 mg/dL vs 1.68 mg/dL, P = .66) were comparable. Although HbA1c levels were elevated in the steroid group (5.47%, 5.87%; P = .003), no significant deterioration was observed in the EVR group without additional insulin administration (6.10%, 6.47%; P = .21). Cytomegalovirus infection rate was significantly lower in the EVR group than in the steroid group (18.2% vs 63.6%, P = .026). CONCLUSION: Conversion from steroid to EVR in ABOi kidney transplant recipients maintained excellent graft outcomes and avoided diabetes progression and cytomegalovirus infection.

Desensitization with the Use of an Antibody Removal-Free Protocol in ABO-Incompatible Kidney Transplant Recipients with a Low Anti-A/B Antibody Titer.

BACKGROUND: Desensitization for ABO-incompatible (ABOi) kidney transplantation mainly comprises removal of antibodies with the use of apheresis and suppression of antibody (Ab) production with the use of rituximab. This study aimed to estimate the outcomes of ABOi kidney transplantation with the use of an Ab removal-free protocol to avoid complications associated with apheresis. METHODS: A total of 32 de novo consecutive adults who underwent ABOi living-donor kidney transplantation were retrospectively evaluated. Our protocol for ABOi recipients was stratified and fixed according to the anti-A/B Ab titer at baseline before desensitization. Desensitization was performed before transplantation with 0-4 sessions of plasmapheresis or double-filtration plasmapheresis and 1-2 administrations of rituximab at 100 mg/body. Graft outcomes, anti-A/B Ab titer, and plasma fibrinogen level were compared between the Ab removal (n = 21) and Ab removal-free (n = 11) groups. RESULTS: Between the Ab removal and Ab removal-free groups, the graft loss rate (4.8% vs 0.0%; P = 1.0), acute rejection rate (19.0% vs 0.0%; P = .14), and serum creatinine level (1.74 vs 1.40 mg/dL, P = .53) were similar. The anti-A/B Ab titer was maintained at a low level until postoperative month 12 in both groups. The plasma fibrinogen level on the operation day was significantly lower in the Ab removal group than in the Ab removal-free group (163.4 vs 250.2 mg/dL; P < .001). CONCLUSIONS: Desensitization with the use of an antibody removal-free protocol for ABOi kidney transplant recipients with a low anti-A/B Ab titer can maintain excellent graft outcomes and avoid postoperative bleeding risk.

Effective and Safe Reduction of Conventional Immunosuppressants Using Everolimus in Maintenance Kidney Transplant Recipients.

BACKGROUND: Adverse events due to conventional immunosuppressive therapy decrease both graft and patient survival. We aimed to establish a new protocol using everolimus (EVR) to safely minimize conventional immunosuppressants in maintenance kidney transplant recipients. METHODS: A total of 86 consecutive kidney transplant recipients with no complications were maintained with triple-drug combination therapy (conventional group). In case of complications, the administration of very low-dose tacrolimus (C0: 5.0 to <3.0 ng/mL), reduced mycophenolate mofetil (1000-1500 to 500-1000 mg), and EVR (C0: 3.0-5.0 ng/mL) and methylprednisolone withdrawal (2-4 to 0 mg) were simultaneously conducted (EVR group). Graft survival and acute rejection rate were compared between groups. Within the EVR group, the dose of conventional immunosuppressants was compared between pre- and post-EVR administration. Renal function was evaluated 1 year post-EVR administration. RESULTS: All grafts survived in the conventional (n = 50) and EVR (n = 36) groups, and biopsy-proven acute rejection rate exhibited no significant difference between these groups (12% vs 17%; P = .55). Furthermore, no acute rejection occurred post-EVR administration. In the EVR group, all immunosuppressants significantly decreased post-EVR administration compared with those pre-EVR administration (P < .01), and serum creatinine significantly improved at postoperative year 1 (P = .031). CONCLUSIONS: EVR administration enables very low-dose tacrolimus administration, helps reduce mycophenolate mofetil and steroid withdrawal, and ameliorates renal function in maintenance kidney transplant recipients experiencing complications associated with conventional immunosuppressive therapy.

Selection Criteria for Kidney Laterality in Retroperitoneoscopic Living Donor Nephrectomy and the Usefulness of Pretransplant Intervention.

OBJECTIVES: To evaluate the selection criteria for kidney laterality and the usefulness of pretransplant intervention in living donor nephrectomy. METHODS: We compared conventional and revised criteria. The conventional criteria were that left kidneys were chosen in preference and provided the kidney with the fewest structural abnormalities and lowest functional decline and that most renal arteries remained in the donor. From April 2013, we allowed the use of left kidneys with double renal arteries. Patient characteristics and surgical outcomes were retrospectively compared between right and left retroperitoneoscopic living donor nephrectomies. RESULTS: We compared data for 30 right kidney and 222 left kidney nephrectomies. Right kidneys were selected because of multiple renal arteries (n = 18), structural abnormalities (n = 10) of the left kidney, or functional decline (n = 2) of the right kidney. Right retroperitoneoscopic nephrectomies were associated with significantly longer operating times (267 minutes vs 241 minutes), larger blood losses (240 g vs 55 g), and higher open conversion rates (10% vs 0.9%). Pretransplant intervention was necessary for structural abnormalities in right kidneys, but the amended selection criteria resulted in fewer right nephrectomies. Pretransplant intervention was still necessary by ex vivo arterial anastomosis for multiple left renal arteries, which increased the total ischemia time (94 minutes vs 64 minutes); however, post-transplantation renal function was not significantly different. CONCLUSIONS: Pretransplant intervention was beneficial both for repairing structural abnormalities and for reducing the difficulties of retroperitoneoscopic living donor nephrectomy.

Cyclosporine-sparing effect of basiliximab in renal transplant recipients with mycophenolate mofetil.

UNLABELLED: Basiliximab added to a maintenance regimen consisting of cyclosporine microemulsion and mycophenolate mofetil was studied for its effectiveness in allowing early steroid withdrawal in renal transplantation. Furthermore, the cyclosporine-sparing effects between groups with and without basiliximab induction therapy were compared. PATIENTS: Between September 2001 and June 2003, 90 patients underwent renal transplants with cyclosporine-based immunosuppression, namely, cyclosporine, mycophenolate mofetil, and methylprednisolone, (group 1; n = 25). During the latter half of the study basiliximab was administered during the induction phase (group 2; n = 65). In group 2, steroids were completely withdrawn on postoperative day 14 in 57 patients. RESULTS: The incidence of acute rejection was significantly higher among group 1 patients (P = .005). The incidence of steroid-resistant rejection in group 1 patients was significantly higher (P = .025). At each time point cyclosporine levels in group 1 patients were significantly higher (P < .01). The incidence of infection was comparable between the groups. Patient and graft survival rates in group 1 were 100% and 100%; in group 2, they were 99% and 99%, respectively. In group 2, steroids were discontinued in 57 patients with permanent withdrawal achieved in 32 patients (56%). CONCLUSION: The use of basiliximab, together with mycophenolate mofetil allowed for a significant reduction in the cyclosporine dose without increasing the risk of acute rejection. Although further follow-up is necessary to confirm the effect, this regimen may attenuate cyclosporine nephrotoxicity thereby affecting the long-term outcomes of renal transplantation.

Impact of Renal Transplantation and Nephrectomy on Urinary Soluble Klotho Protein.

BACKGROUND: Klotho is a single-pass transmembrane protein predominantly expressed in the kidneys. The soluble form of klotho has been shown to participate in various pathophysiological activities. However, information regarding the kinetics of soluble klotho remains limited. We herein assessed serial changes in the amounts of 24-hour urinary excreted soluble klotho among renal transplant recipients and concomitant living donors before and after transplantation. METHODS: A total of 15 recipients and donors were included in the current study, and the amounts of urinary soluble klotho were quantified using a sandwich enzyme-linked immunosorbent assay. RESULTS: Urine samples were available in 6 of the 15 recipients prior to the procedure. The amounts of urinary klotho in these 6 recipients and overall living donors at the baseline were 58.6 ng/day (IR: 29.3-142) and 698.8 ng/day (IR: 62.3-1619.5), respectively. Those in the recipients on postoperative day 2 (median 522.3 ng/day; IR 337.1-1168.5, P < .05) and day 5 (median 723.2 ng/day; IR 254.7-1238.6, P < .05) were significantly higher than the baseline values. Among the living donors, only a transient increase was observed in the amounts of urinary klotho on postoperative day 2. CONCLUSION: The current data regarding the urinary soluble klotho in recipients support the hypothesis that the kidney is a major source of urinary soluble klotho among the numerous components of the urinary tract. In living donors, the complex nature of events associated with acute reductions in the renal mass may modulate the release of soluble klotho from the kidneys into the urine.

Treatment of glioblastoma by direct inoculation of concentrated high titer-recombinant retrovirus carrying the herpes simplex virus thymidine kinase gene.

We prepared retroviruses carrying the lacZ gene or herpes simplex virus thymidine kinase (HTK) gene with titers of 1.4-2.5 x 10(11) colony-forming units (cfu)/ml, and stereotaxically inoculated only 3 microliters of the retroviruses into a mouse glioma model. This resulted in highly efficient transduction in vivo. The transduced glioma cells migrated far from the implantation site, potentiating the induction of the remarkable bystander effect. Following repetitive ganciclovir (GCV) intraperitoneal injection, effective killing of glioma cells in the mouse brain was observed. The transduction efficiency was nearly as high as that observed for the implantation of high-titer retrovirus-producing fibroblasts. Eighty per cent of brain tumor-bearing mice were completely cured by our treatment protocol using concentrated HTK-harboring retroviruses. Our results suggest that repeated inoculations of high-titer retroviruses carrying the HTK gene followed by GCV treatment may be a promising strategy for the clinical treatment of malignant gliomas. To achieve further safety in the gene therapy of glioma, genes abundantly expressed in human glioblastoma were searched by the Serial Analysis of Gene Expression (SAGE) technique. Among the top-147 most expressed tags in glioblastoma, we found a tag, TTTTGGGTAT, originated from an unidentified gene, which was not detected in human astrocyte cultures. Real-time quantitative RT-PCR showed that MAGE-E1 expression was 2.6-15 fold enriched in glioblastoma relative to human astrocytes. Expressed Sequence Tags (ESTs) containing this tag were homologous to melanoma-associated antigen gene (MAGE) family, and this new cDNA, named MAGE-E1, was cloned by 5'-rapid amplification of cDNA ends (RACE) technique. MAGE-E1 expression was enriched in glioblastoma and low in other cancers, and MAGE-E1 expression was detected only in brain and ovary among normal tissues. These results indicate that MAGE-E1 is a novel and glioma-specific member of MAGE family, which can be applied to glioma-specific gene transduction.

Potent immunosuppression for ABO-incompatible renal transplantation may not be a risk factor for malignancy.

ABO-incompatible (ABOi) renal transplantation has been increasing, but malignant tumor is a troubling complication of kidney transplantation due to potent immunosuppression. Few previous studies, however, have demonstrated that potent immunosuppression for ABOi living-donor renal transplantation (LDRT) is a risk factor for malignancy. In the present research, data on 252 LDRT patients ftom 2003 to 2008 were retrospectively analyzed to clarify whether ABOi LDRT was associated with malignancy. A potent immunosuppressive regimen for ABOiLDRT consisted of splenectomy, cyclophosphamide, and double-filtration plasmapheresis to minimize the risk of antibody-mediated rejection, in addition to conventional immunosuppresssants including calcineurin inhibitor, prednisolone, and anti-CD25 monoclonal antibody. A total of 11 incidences of malignancy were observed during a median follow-up of 48 months. The incidence rates in ABO-compatible (ABOc; n = 189) and ABOi (n = 63) LDRT groups were 4.2 % (8/189) and 4.8 % (3/63), respectively. Kaplan-Meier survival analysis showed no statistical difference in event-free survival for malignancy between ABOc and ABOiLDRT groups (log-rank P = .73). Multivariable Cox regression analyses identified no associations of malignancy with ABOi LDRT or any immunosuppressant use. In conclusion, our investigation suggested that potent immunosuppression with splenectomy and cyclophosphamide for ABOi LDRT may not be a risk factor for malignancy.

Clinical characteristics and outcomes of renal transplantation in elderly recipients.

BACKGROUND: Elderly renal transplant candidates constitute one the fastest-growing populations among end-stage renal disease patients. Since the impacts of advanced recipient age have not yet been fully defined, we evaluated the clinical characteristics and outcomes of elderly renal transplant recipients. METHODS: Among 564 adult renal transplant recipients, at our center between 2000 and 2009, 64 were at least 60 years of age (Elderly group), and 500 were younger than 60 years (Young group) at the time of the procedure. We compared their clinical features and surgical management. RESULTS: There were significant differences in mean donor age (55.6 years vs. 53.2 years, P = .030) and gender mismatch (77.0% vs. 63.4%, P = .035). However, there were no significant differences between the two groups in patient and graft survivals (P = .177 and P = .365, respectively). Malignancy after transplantation was a significant risk factor upon univariate evaluation but only ABO incompatibility upon multivariate analysis of patient and graft survival. The main cause of graft loss among the Elderly group was death with a functioning graft due to heart failure. CONCLUSIONS: Renal transplantation is a feasible, safe option for the elderly and should be actively implemented. However, screening for cancer and heart disease should be mandatory to improve outcomes.

Improved outcomes of renal transplantation from cardiac death donors: a 30-year single center experience.

Outcomes of renal transplantation from donation after cardiac death (DCD) donors over 30 years were analyzed. Between 1975 and 2004, 256 renal transplantations from DCD donors were performed. The recipients were divided into four groups according to a time period as follows: 1975-1979 (Group 1; n = 18), 1980-1989 (Group 2; n = 81), 1990-1999 (Group 3; n = 84) and 2000-2004 (Group 4; n = 73). Of the 256 transplanted kidneys from DCD donors, 38 (15%) functioned immediately after transplantation. The incidence of delayed graft function (DGF) was 72%. Warm ischemic time and total ischemic time were 7.4 +/- 9.4 min and 11.9 +/- 5.6 h, respectively. The overall graft survival rates at 1, 5 and 10 years were 80%, 72% and 53%, respectively. Graft survival rates in each group have continually improved over time (5-year graft survival; 23% vs. 64% vs. 74% vs. 91%, respectively). However, there was no significant difference in graft survival rates between the groups of patients who survived with a functioning graft for more than 1 year. A multivariate Cox regression analysis showed acute rejection and donor age to be independently associated with graft outcome. DCD donors are a valuable source of kidneys for transplantation with promising long-term outcomes.

Eradication of murine brain tumors by direct inoculation of concentrated high titer-recombinant retrovirus harboring the herpes simplex virus thymidine kinase gene.

Implantation of retrovirus-producing cells within a tumor has been demonstrated to eliminate malignant brain tumors effectively in animal models. In our previous study, the implantation of high-titer retrovirus-producing fibroblasts into tumors resulted in highly efficient transduction in vivo. The transduced glioma cells migrated far from the implantation site, potentiating the induction of the remarkable bystander effect. It is also possible, however, that the implantation of murine fibroblast-derived virus-producing cells may induce an immune response in patients. In this study, we prepared retroviruses carrying the herpes simplex virus thymidine kinase (HTK) gene with titers of 1.4--2.5 x 10(11) colony-forming units (c.f.u.)/ml, and stereotactically inoculated only 3 microl of the HTK-bearing retroviruses into the brain tumors of mice. Following repetitive ganciclovir (GCV) intraperitoneal injection, effective killing of glioma cells in the mouse brain was observed. The transduction efficiency was nearly as high as that observed for the implantation of high-titer retrovirus-producing fibroblasts. Eighty percent of brain tumor-bearing mice were completely cured by our treatment protocol using concentrated HTK-harboring retroviruses. Our results suggest that repeated inoculations of high-titer retroviruses carrying the HTK gene followed by GCV treatment may be a promising strategy for the clinical treatment of malignant gliomas.

Brain malformations caused by retroviral vector-mediated gene transfer of hippocampal cholinergic neurostimulating peptide precursor protein into the CNS via embryonic mice ventricles.

Hippocampal cholinergic neurostimulating peptide precursor protein (HCNP-pp) is a unique multifunctional protein, being not only the precursor of HCNP, which promotes the phenotype development of septo-hippocampal cholinergic neurons, but also the binding protein of phosphatidylethanolamine, ATP, Raf-1 kinase (known as "Raf-1 kinase inhibitory factor" in peripheral organs), and serine protease. We obtained a high-titer retroviral vector harboring HCNP-pp cDNA by the use of a modified packaging cell line and centrifugation, and by injecting it into embryonic mouse ventricles, we investigated the function of its gene product within the central nervous system (CNS). We found that efficient transduction into hippocampal pyramidal neurons can be achieved by injecting the vector into embryonic brain ventricles on embryonic day 14 (E14). Three days after receiving the intraventricular injection of the high-titer HCNP-pp retrovirus vector on E14, the tissues around the ventricles showed an overexpression of HCNP-pp. This was accompanied by a reduced amount of activated MEK and Erk (as analyzed by histochemical and Western blot methods), suggesting that HCNP-pp also regulates the MAP-kinase cascade within the CNS. Surprisingly, mouse brains that received the HCNP-pp retroviral vector showed massive malformation of the hippocampus and cerebellum when examined 30 days after birth. This shows that strictly regulated HCNP-pp gene expression is necessary for the normal development of the mouse brain, and that the moderate overexpression achieved by retroviral vector-mediated gene transfer is sufficient to cause severe abnormality of entire brain structures.