PubMed Health⌕ Search

Biomedical subjects

Naohiro Wada

Publications and source records attributed to Naohiro Wada.

11 recordsLinked to original sources
PubMed2006

Triggers of relapse in steroid-dependent and frequently relapsing nephrotic syndrome.

An awareness of the triggers of relapse is critical for the control of steroid-dependent, frequently relapsing nephrotic syndrome (SDFRNS). We have investigated the triggers, usually described as 'episodes', to such relapses within a temporal context. Thirty-five patients with SDFRNS were analyzed retrospectively. A total of 442 relapses occurred in 2499 patient-months. The relapses were classified into two groups: those with episodes (E+) and those without episodes (E-). There were 135 E+ relapses and 296 E- relapses. The common cold was the most common episode (52%) of E+ relapse, followed by school events (18%). These E+ relapses occurred almost evenly throughout the 4 weeks between each follow-up visit. Conversely, 161 (55%) of the 296 E-z relapses occurred within the 3-day period preceding the patient's appointment (relapse-related hospital visit, RRHV). McNemar's test revealed that the concentration of relapses in this period was statistically significant (P < 0.00011). In addition, 15 out of 26 RRHV without additional therapy showed a spontaneous remission. From a chronological perspective, the common cold and school events as well as up-coming hospital visits may trigger relapses in SDFRNS patients.

Adolescent↗
PubMed2006

A survey of peritonitis and exit-site and/or tunnel infections in Japanese children on PD.

To obtain data on peritonitis and exit-site and/or tunnel infections (ESI/TI) in Japanese children undergoing peritoneal dialysis (PD) from January 1999 through June 2003, we surveyed 22 members of the Japanese Study Group of Pediatric Peritoneal Dialysis (JSPPD) by questionnaire. One hundred and thirty patients were eligible. Seventy episodes of bacterial peritonitis occurred in 45 patients (0.17 episodes/patient-year), and 123 ESI/TI occurred in 60 patients (0.29 episodes/patient-year). S. aureus and MRSA were found to be the causative organisms in 39% and 13% of the peritonitis episodes, and in 59% and 20% of the ESI/TI, respectively. Tunnel infection was found in 55% of the MRSA peritonitis episodes. Eleven percent of the peritonitis episodes relapsed, and 19% needed hemodialysis. One patient died due to MRSA peritonitis. The PD catheter was removed in all fungal and 78% of MRSA peritonitis. However, the type of organism did not influence the need for catheter-related surgery for ESI/TI. Neither peritonitis nor ESI/TI was prevented by the use of a swan-neck catheter, a downward-pointing exit site, povidone iodine exit-site care, bathing instruments, or nasal mupirocin. In conclusion, MRSA peritonitis was not uncommon in children in Japan, was frequently associated with tunnel infections, and had a poor outcome. No association was found between the occurrence of infection and preventive measures previously reported as effective. Alternative approaches are needed in children, especially for MRSA.

Anti-Bacterial Agents↗
PubMed2006

Kidney transplantation in pediatric recipients with mental retardation: clinical results of a multicenter experience in Japan.

BACKGROUND: There are few published reports on kidney transplantation (KT) in physically handicapped patients with mental retardation. The aim of this study is to clearly identify the outcome of KT in these patients and clarify whether handicapped patients can be candidates for KT. METHODS: Our study identified 25 multiply handicapped transplant recipients from 8 institutions. Causes of mental retardation were chromosomal abnormality in 5 patients, genetic syndrome in 10 patients, developmental brain anomaly in 2 patients, and other or unknown causes in 8 patients. Primary diseases leading to end-stage renal disease were congenital urinary tract anomaly in 12 patients, focal segmental glomerulosclerosis in 3 patients, cystic kidney disease in 3 patients, and other in 7 patients. RESULTS: Twenty-three patients received living-related transplants from a parent and 2 patients received cadaver transplants. Twenty-two patients were on peritoneal dialysis therapy, 2 patients were on hemodialysis therapy at the time of KT, and 1 patient underwent preemptive KT. Eleven acute rejection episodes occurred in 8 patients. All episodes were completely reversed with treatments that included mainly methylprednisolone pulse therapy. Posttransplantation lymphoproliferative disorder occurred in 2 patients. Follow-up data showed that all grafts were functioning during a mean observation period of 41.1 months (range, 4 to 187 months). All persons providing primary support for patients were satisfied with the KT and believed that quality of life was improved in both transplant recipients and themselves. CONCLUSION: Results indicate that KT is not contraindicated in handicapped patients, but cannot determine which patients are unsuitable to undergo KT.

Adolescent↗
PubMed2006

Charge selective function in childhood glomerular diseases.

The charge selectivity (CS) function in human renal disease has not been unequivocally demonstrated to date. However, the clearance ratio of IgA to IgG may be theoretically useful in estimating CS in humans, since IgA and IgG have similar sizes and tertiary structures, but distinct isoelectric points (3.5-5.5 [IgA] and 4.5-9.0 [IgG]), and Stokes-Einstein radius: 61 A (IgA) and 49-60 A (IgG). Two-dimensional electrophoresis with the following immunoblotting revealed that the considerably anionic portion (isoelectric points [pI] <4.0) of IgA, visible in serum, was absent in the urine in steroid-sensitive nephrotic syndrome (SSNS) but present in the same during IgA nephropathy (IgAN) and membranoproliferative glomerulonephritis (MPGN). A latex assay revealed the CS index (CSI) was significantly low in patients with podocyte disease (group A), including SSNS, focal and segmental glomerulosclerosis (FSGS) and Finnish-type congenital nephrotic syndrome (FCNS), but high in those with Alport syndrome (AS), IgAN, Henoch-Schönlein purpura nephritis (HSPN), and MPGN (group B). The linear regression analysis of the IgA size selectivity index (IgA SSI; clearance ratio of IgA to transferrin) and SSI (clearance ratio of IgG to transferrin), which represents the clearance ratio of IgA to IgG referring to the transferrin clearance, revealed the influence of the charge more accurately. Indeed, the slope of the regression lines of IgA SSI (y) to SSI (x) were concluded to be y = 0.39x (group A) and y = 1.05x (group B), respectively. These results suggested that the charge selective barrier among podocyte diseases (group A) is preserved to some degree, but lost in cases of nephritis and AS (group B).

Adolescent↗
PubMed2006

[Sequential combined liver-kidney transplantation for a one-year-old boy with infantile primary hyperoxaluria type 1].

We present the case of a one-year-old male patient with infantile primary hyperoxaluria type 1 (PH1). The patient visited hospital because of growth delay and poor feeding when he was six months old, and was diagnosed as PH1 with chronic renal failure. He underwent peritoneal dialysis until receiving a living-related liver transplantation when he was seventeen months old, and after the operation, underwent hemodialysis or hemodiafiltration four times per week. Six months after the liver transplantation, his serum oxalate level decreased to around 20 micromol/l and a living-related kidney transplantation was successfully performed. Nine months have passed since the kidney transplantation, and the patient's liver and kidney functions have been good and his growth and development much better than before the sequential liver and kidney transplantation. However, his serum and urine oxalate levels remained high and he has required high dose hydration to prevent deposition of calcium oxalate crystals in his grafted kidney. The key-points for treating infantile PHI patients are summarized as follows; 1) make a precise diagnosis as soon as possible, 2) perform a combined liver-kidney transplantation successfully, 3) conduct careful monitoring of the serum and urine oxalate levels and continue adequate hydration after kidney transplantation until the serum and urine oxalate levels normalize. Furthermore, cooperation between the medical staff and the patient's family seems to be essential.

Humans↗
PubMed2005

Analysis of NPHS1, NPHS2, ACTN4, and WT1 in Japanese patients with congenital nephrotic syndrome.

BACKGROUND: Congenital nephrotic syndrome (CNS) causes significant renal failure, and is classified into two types: (1) Finnish type; and (2) other, including diffuse mesangial sclerosis. Mutations of NPHS1 and NPHS2, which encode the slit diaphragm components nephrin and podocin, cause CNS and autosomal-recessive familial steroid-resistant nephrotic syndrome, respectively. Most patients with Finnish-type CNS in Europe and the United States have NPHS1 mutations. However, NPHS2 mutations have been detected in some cases. Mutations in ACTN4, encoding alpha-actinin-4, cause an autosomal-dominant focal segmental glomerulosclerosis. alpha-actinin-4 stabilizes the podocyte cytoskeleton structure, connecting with actin filaments. WT1 mutations, causing Wilm's tumor, have been demonstrated in some CNS patients with diffuse mesangial sclerosis. Systematic investigation of genes for CNS in Japan has never been performed. METHODS: To clarify the role of mutations in these four genes, we used polymerase chain reaction (PCR) and direct sequencing to investigate all exons and exon-intron boundaries for these genes in 13 unrelated CNS patients from regional pediatric kidney disease centers in Japan. RESULTS: A novel homozygous nonsense mutation of NPHS1, E246X in exon 7, and a novel homozygous deletion mutation of NPHS1, 2156_2163del in exon 16 were detected in one patient each. A novel homozygous nonsense mutation of NPHS2, R196X in exon 5, was found in one patient, and the same heterozygous nonsense mutation was detected in another. No ACTN4 or WT1 mutations were detected. CONCLUSION: These studies demonstrate that mutation of NPHS1 is not a major cause of CNS in Japanese patients, and that mutation of NPHS2 can be responsible for CNS in this population.

Actinin↗
PubMed2004

The diagnostic value of serum concentrations of 2-(alpha-mannopyranosyl)-L-tryptophan for normal renal function.

BACKGROUND: We have previously reported that the serum concentration of 2-(alpha-mannopyranosyl)-L-tryptophan (MPT), tryptophan glycoconjugate, is a more accurate measure of renal function than that of serum creatinine concentration. The aim of the present study was to compare the diagnostic value of serum concentrations of MPT and creatinine as a measure of normal renal function. METHODS: A total of 156 subjects with serum creatinine concentration < or =1.60 mg/dL aged 0 to 88 years were recruited. Serum concentrations of MPT and creatinine, and creatinine clearance calculated by Cockcroft-Galt formula were determined. A diagnostic accuracy of serum concentrations of MPT and creatinine for normal renal function was analyzed by using receiver-operating characteristics (ROC) curves. In 82 subjects with normal renal function defined as calculated creatinine clearance > or =80 mL/min (aged 6 to 68 years), the correlations between age and/or urinary creatinine excretion, which is related to muscle mass, and serum concentrations of MPT or creatinine, were determined. RESULTS: In the ROC curve, the area under the curve (AUC) in serum MPT concentration was significantly greater than that of creatinine (0.855 versus 0.800, respectively, P < 0.001) and the cut-off levels associated with the greatest diagnostic accuracy were 90 ng/mL for serum MPT concentration and 0.70 mg/dL for serum creatinine concentration. The sensitivity, specificity, and positive and negative predictive values were 69.5%, 85.1%, 83.8%, and 71.6% for serum MPT concentration, and 53.7%, 81.1%, 75.9%, and 61.2% for serum creatinine concentration. A close correlation existed between serum creatinine concentration and age (r= 0.798, P < 0.0001) in 23 subjects aged 20 years or younger. Conversely, serum MPT concentration remained unchanged regardless of age (r=-0.135, P= 0.228). Furthermore, a close correlation existed between serum creatinine concentration and urinary creatinine excretion (r= 0.817, P < 0.0001), but not between serum MPT concentration and urinary creatinine excretion (r= 0.082, P= 0.461). CONCLUSION: The concentration of serum MPT is a more reliable diagnostic parameter than that of serum creatinine as a measure of normal renal function, and renal function can be compared in subjects independently of age and muscle mass when serum MPT concentration is measured.

Adolescent↗
PubMed2004

Cationic charge-preferential IgG reabsorption in the renal proximal tubules.

BACKGROUND: The brush border of the renal proximal tubules has a polyanionic charge. Since immunoglobulin G (IgG) molecules have a wide range of charge diversity, reabsorption of urinary IgG molecules are supposed to be influenced by the electrostatic interaction. METHODS: Charge diversity of serum and urinary IgG molecules in patients with various renal diseases (N= 12) and premature neonates (N= 3) were analyzed by isoelectric focusing and Immunoblotting. RESULTS: In patients with glomerular diseases, urinary IgG was solely composed of neutral and anionic IgG, whereas that of the cationic part (isoelectric point >8) was not observed. By contrast, in patients with proximal tubular diseases (Dent's disease and idiopathic Fanconi syndrome), the proportion of the cationic IgG was similar to that of serum IgG. In addition, the cationic part of IgG in the urine was found in the neonates with a gestational age of 28 and 31 weeks, but not found in those of 35 weeks. CONCLUSION: The results suggest that renal proximal tubules reabsorb the urinary IgG in a cationic preferential way, and this mechanism requires renal maturation.

Adolescent↗
PubMed2003

NPHS2 mutations in sporadic steroid-resistant nephrotic syndrome in Japanese children.

Podocin is an integral membrane protein encoded by NPHS2, which is mapped to 1q25-31 and is exclusively expressed in glomerular podocytes. NPHS2 mutations are responsible for autosomal recessive familial steroid-resistant nephrotic syndrome (SRNS) with minor glomerular abnormalities or focal segmental glomerulosclerosis (FSGS), which is characterized by early childhood onset (age less than 6 years) and rapid progression to chronic renal insufficiency. This gene mutation is also responsible for an adolescent/adult onset form of autosomal recessive familial FSGS with heavy proteinuria. It has been demonstrated that sporadic SRNS and heavy proteinuria are also due to NPHS2 gene mutations. We isolated genomic DNA from 36 Japanese children with chronic renal insufficiency caused by SRNS or heavy proteinuria, and analyzed all eight exons and exon-intron boundaries of NPHS2 using the polymerase chain reaction and direct sequencing. The age at onset of disease was 3.9+/-0.5 years. There were 29 patients with SRNS and 7 with heavy proteinuria without nephrotic syndrome at the onset, but all patients developed chronic renal insufficiency 4.6+/-0.8 years after the onset. A new homozygous missense variant of NPHS2, G34E (G101A) in exon 1, was detected in 1 of 36 patients. However, this homozygous variant was also found in 1 of 44 normal controls, suggesting that the mutation is a polymorphism. Two silent variants (T954C and A1038G) in exon 8 of this gene were also identified in some of the patients and normal controls, indicating that the silent variants are also polymorphisms. There was no significant difference in the genotypic and allelic frequencies of T954C and A1038G polymorphisms between the patients and normal controls. In conclusion, NPHS2 gene mutations are not a major cause of chronic renal insufficiency caused by sporadic SRNS or heavy proteinuria in Japanese children.

Adult↗