Ultraviolet photochemical reaction of [Fe(III)(C2O4)3](3-) in aqueous solutions studied by femtosecond time-resolved X-ray absorption spectroscopy using an X-ray free electron laser.

Time-resolved X-ray absorption spectroscopy was performed for aqueous ammonium iron(III) oxalate trihydrate solutions using an X-ray free electron laser and a synchronized ultraviolet laser. The spectral and time resolutions of the experiment were 1.3 eV and 200 fs, respectively. A femtosecond 268 nm pulse was employed to excite [Fe(III)(C2O4)3](3-) in solution from the high-spin ground electronic state to ligand-to-metal charge transfer state(s), and the subsequent dynamics were studied by observing the time-evolution of the X-ray absorption spectrum near the Fe K-edge. Upon 268 nm photoexcitation, the Fe K-edge underwent a red-shift by more than 4 eV within 140 fs; however, the magnitude of the redshift subsequently diminished within 3 ps. The Fe K-edge of the photoproduct remained lower in energy than that of [Fe(III)(C2O4)3](3-). The observed red-shift of the Fe K-edge and the spectral feature of the product indicate that Fe(III) is upon excitation immediately photoreduced to Fe(II), followed by ligand dissociation from Fe(II). Based on a comparison of the X-ray absorption spectra with density functional theory calculations, we propose that the dissociation proceeds in two steps, forming first [(CO2 (•))Fe(II)(C2O4)2](3-) and subsequently [Fe(II)(C2O4)2](2-).

Protective effects of mineralocorticoid receptor blockade against neuropathy in experimental diabetic rats.

AIMS: Mineralocorticoid receptor (MR) blockade is an effective treatment for hypertension and diabetic nephropathy. There are no data on the effects of MR blockade on diabetic peripheral neuropathy (DPN). The aim of this study was to determine whether MRs are present in the peripheral nerves and to investigate the effectiveness of MR blockade on DPN in streptozotocin (STZ)-induced diabetic rats. METHODS: Expression of MR protein and messenger RNA (mRNA) was examined in the peripheral nerves using Western blot analysis and RT-PCR. We next studied the effects of the selective MR antagonist eplerenone and the angiotensin II receptor blocker candesartan on motor and sensory nerve conduction velocity (NCV), morphometric changes and cyclooxygenase-2 (COX-2) gene and NF-κB protein expression in the peripheral nerves of STZ-induced diabetic rats. RESULTS: Expression of MR protein and mRNA in peripheral nerves was equal to that in the kidney. Motor NCV was significantly improved by 8 weeks of treatment with either eplerenone (39.1 ± 1.2 m/s) or candesartan (46.4 ± 6.8 m/s) compared with control diabetic rats (33.7 ± 2.0 m/s) (p < 0.05). Sensory NCV was also improved by treatment with candesartan or eplerenone in diabetic rats. Eplerenone and candesartan caused significant improvement in mean myelin fibre area and mean myelin area compared with control diabetic rats (p < 0.05). COX-2 mRNA and NF-κB protein were significantly elevated in the peripheral nerves of diabetic rats compared with control rats, and treatment with eplerenone or candesartan reduced these changes in gene expression (p < 0.05). CONCLUSION: MR blockade may have neuroprotective effects on DPN.

Sclerosing encapsulating peritonitis in pediatric peritoneal dialysis patients.

The aim of this study was to define the incidence and characteristics of sclerosing encapsulating peritonitis (SEP) in pediatric peritoneal dialysis (PD) patients in Japan. A questionnaire was sent to all dialysis units with at least two pediatric PD patients. Among 687 patients registered, 11 cases (1.6%) of SEP were diagnosed. The mean age of patients with SEP at the start of PD was 9.7+/-3.6 years and at SEP diagnosis, 19.1+/-3.8 years. All patients had undergone PD for more than 5 years, and the mean PD duration was 9.6+/-3.3 years. SEP was diagnosed in 6.6% and 12% of patients dialyzed for >5 years and >8 years, respectively. The incidence of peritonitis among patients with SEP was not different from that among the Japanese pediatric registry. All patients had virtually no residual urine volume and 9 had impaired peritoneal ultrafiltration. Peritoneal calcification was the most-frequent radiological finding. Peritoneal biopsy was performed in 7 patients and confirmed sclerotic peritonitis in all. Ten patients transferred to hemodialysis, and only 1 patient underwent surgery. Three patients died. We recommend that patients on PD for more than 5 years who have impaired peritoneal ultrafiltration or peritoneal calcification should be carefully managed as presumptive cases of SEP.

Membranoproliferative glomerulonephritis in congenital portosystemic shunt without liver cirrhosis.

We report two cases with congenital portosystemic shunt who developed renal lesions without liver cirrhosis. Clinically, both cases showed proteinuria and mild hematuria at 9 and 6 years of age, respectively. In one case, the renal lesion was associated with normal renal function, but nephrotic syndrome followed by chronic renal failure were noted in the other. Renal biopsies showed characteristic histological features of membranoproliferative glomerulonephritis (MPGN) with IgA deposits along the glomerular capillary wall. Our cases strongly suggest the association between congenital portosystemic shunt and renal region. The shunt ratio may be an important predisposing factor for this type of nephropathy since a high shunt ratio (> 90%) was noted in both cases.

Chloride channel CLCN5 mutations in Japanese children with familial idiopathic low molecular weight proteinuria.

BACKGROUND: Familial idiopathic low molecular weight proteinuria (FILMWP) is a renal proximal tubulopathy characterized by mild proteinuria consisting of low molecular weight proteinuria and relatively conserved renal function in young patients, but without rickets. Mutations in the renal chloride channel CLCN5 gene have been reported in three disorders of hypercalciuric nephrolithiasis and in FILMWP. METHODS: To assess the relationship between molecular defects and phenotypic variations, we analyzed the CLCN5 gene from three additional Japanese families with FILMWP using single-strand conformation polymorphism and sequencing. RESULTS: We identified three mutations: a single base insertion at codon 514; a single base deletion at codon 116; and a nonsense mutation, R704X. The R704X mutation is identical to that found in X-linked recessive nephrolithiasis, but there was no renal failure in our patient. The first two mutations caused a shift in the reading frame, and all introduced a premature stop codon, resulting in synthesis of truncated CLC-5 proteins that lacked 220 (29%), 610 (82%), and 43 (6%) amino acids, respectively. These mutations were demonstrated to cosegregate with the disease in each of the three families. CONCLUSIONS: We conclude that the CLCN5 gene is responsible for the renal proximal tubulopathy in many Japanese families and suggest that molecular defects, environmental factors, or other modifying genes may account for the different phenotypes.

Developmental changes in carbonic anhydrase II in the rat kidney.

We examined the distribution and maturational changes of carbonic anhydrase I (CAI) and carbonic anhydrase II (CAII) in microdissected nephron segments of Sprague-Dawley rats. CAI and CAII proteins were measured by enzyme-linked immunosorbent assay. CAI was not detected in any nephron segment in 7-week-old rats. CAII was present in the collecting ducts, proximal tubules, and thick ascending limbs of loop of Henle in 7-week-old rats. CAII contents were significantly higher in the early proximal tubules (S1) than in second (S2) and late (S3) portions of the proximal tubules, while the contents in S1 were less than in cortical collecting ducts (CCD), outer stripe and inner stripes of the outer medullary collecting ducts (OMCDo and OMCDi). CAII content in each of S1, CCD, and OMCD of 1-week-old rats was only 14% or less of that of adults, but increased steeply during the 2nd and 3rd weeks of life, reaching almost 40% at 3 weeks of age and 97% at 7 weeks. Our results indicate that CAII is present throughout the entire nephron of the rat, and that CAII content in S1, CCD, and OMCD increases exponentially during the first 7 weeks of life. Our data suggest that the immature low levels of CAII may explain, at least in part, the limited capacity of urinary acidification during neonatal life. Further studies are necessary to establish the role of such changes in CAII content in acid-base homeostasis during neonatal life.

Mutations in the CLCN5 gene in Japanese patients with familial idiopathic low-molecular-weight proteinuria.

Familial idiopathic low-molecular-weight proteinuria (FILMWP) is a renal proximal tubulopathy that occurs predominantly in males. FILMWP is characterized by mild proteinuria consisting of low-molecular-weight proteinuria, aminoaciduria and relatively conserved renal function, but without rickets. To determine whether FILMWP is related to the CLCN5 gene, which is responsible for Dent's disease and two related disorders, we analyzed the CLCN5 gene from four Japanese families with FILMWP. We identified two novel mutations: one was a single base insertion at codon 520 serine in exon 10 and the other was a single base deletion at codon 403 tyrosine in exon 8. These mutations caused a shift in the reading frame, resulting in synthesis of truncated CLC5 proteins that lacked 220 (29%) and 314 (42%) amino acids, respectively. These mutations were demonstrated to cosegregate with the disease in two families, respectively. We conclude that the CLCN5 gene is responsible for this proximal renal tubulopathy in some Japanese families and that FILMWP is possibly a variant of Dent's disease.

Molecular cloning, tissue distribution, and chromosomal localization of human cationic amino acid transporter 2 (HCAT2).

Human cationic amino acid transporter 2 (HCAT2) was isolated from a human intestine cDNA library. The nucleotide sequence of the coding region predicts a 658-amino-acid protein with a calculated molecular weight of 71,669. As 91% of the residues are identical with those of the mouse cationic amino acid transporter 2 (MCAT2), HCAT2 seems to be a human counterpart of MCAT2. We found no isoform as was present in MCAT2. In Northern blot analysis, a single (9.0 kb) HCAT2 mRNA transcript was present in various human tissues. The highest level of expression was observed in skeletal muscle and the lowest level in the kidney. Hydropathy plots indicated that the translated protein is predicted to have 14 transmembrane domains with three potential N-glycosylation sites. Two patients with lysinuric protein intolerance (MIM No. 222700) were analyzed for HCAT2 cDNA but no mutation was detected. The HCAT2 gene was assigned to human chromosome 8p21.3-p22.

The Japanese National Registry data on pediatric CAPD patients: a ten-year experience. A report of the Study Group of Pediatric PD Conference.

OBJECTIVE: Over the past 10 years, we have collected data on pediatric patients less than 16 years of age from the National Registry of CAPD (continuous ambulatory peritoneal dialysis). We present our experience with this population. DESIGN: The database details the patient number, age, weight, height, outcome, cause of death, reason for terminating CAPD therapy, peritonitis, and catheter survival. PATIENTS: Of the 434 patients (239 males, 195 females), 37 patients (8.5%) were under 1 year of age and 164 patients (37.8%) were under 6 years of age. About half of the patients were less than 20 kg in weight, clearly indicating that CAPD was the treatment of choice in young children. The duration on CAPD for these patients was less than 2 years for 233 patients (54%), and was 5 years or more in 48 patients (11%). RESULTS: The outcome of the total patient population of 434 as of May, 1991, is as follows: 229 patients (52.8%) were being successfully treated with CAPD, 47 patients (10.8%) died, and 78 patients (18.0%) received a kidney transplantation. The patient survival rate was 85.6% at 3 years and 81.7% at 5 years. The technique survival rate was 74.9% at 3 years and 63.5% at 5 years. The rate of peritonitis was one episode over 28.6 patient-months. The mean catheter duration was 1.68 years. Peritonitis rate, catheter survival rate, and the rate of tunnel infection were worse in children less than 6 years of age than in older children. CONCLUSION: The excellent patient and technique survival rates indicate that CAPD is an effective treatment for children with end-stage renal disease in Japan. The high infection rates in younger children indicate that extra careful management is needed for this young age group.

Splicing mutations in the COL4A5 gene in Alport's syndrome: different mRNA expression between leukocytes and fibroblasts.

The COL4A5 gene from 40 patients with Alport's syndrome was examined using single-strand conformation substitution at the acceptor site (-2) of intron 50 and a G-to-C substitution at the donor site (+1) of intron 47, respectively. The transcript in peripheral leukocytes from the former had a 10-nucleotide deletion. This shortened transcript was derived from abnormal splicing in a cryptic acceptor site within exon 51. This could be translated into a protein with an alteration of three amino acids followed by premature termination, which eliminated 23 amino acids from the carboxyl end. Gene tracking revealed that the mother and a brother carried the mutant allele. In the latter, the transcript in leukocytes was normal, but that in cultured skin fibroblasts showed skipping of exon 47, the result being that 71 amino acids were absent. Glomerular basement membrane from the patient did not react with the anti-alpha 5(IV) antibody. His maternal grandmother, mother, and a sister, all with abnormal urinalysis, carried the mutant allele. Thus, the appearance of exons of the COL4A5 gene in leukocytes may differ from that in fibroblasts. If kidney mRNA is not available, mRNAs from cultured skin fibroblasts, in addition to leukocytes, can be used for gene analysis in subjects with Alport's syndrome.

Right common iliac arterio-intestinal fistula caused by tubercular peritonitis: report of a case.

A 59-year-old female was admitted with massive hematemesis and melena. A hematological examination revealed that the red blood cell count was 1.31 x 10(6)/mm3, Hb 3.4 g/dl, and Hct 12%. No source of bleeding was found by an emergency endoscopic examination of the esophagus, stomach and duodenum, or by superior mesenteric angiography. At laparotomy a right common iliac arterio-intestinal fistula was found. The microscopic examination of this part of the ileum, including the fistula, revealed the presence of tubercular peritonitis. An extra-anatomic bypass graft using a prosthetic graft was performed between the left and right femoral arteries because reconstruction of the right common iliac artery was impossible.

[Clinicopathological survey of persistent hypocomplementemic glomerulonephritis in children; correlation of DPGN and MPGN type I].

We studied clinicopathologically 19 patients with abnormal urinary findings accompanying with persistent hypocomplementemia under age 15. They consisted of 6 patients with membranoproliferative glomerulonephritis (MPGN) type I, 2 with MPGN type II, 2 with focal MPGN, 8 with diffuse proliferative glomerulonephritis (DPGN), 1 with focal glomerulonephritis (FGN). 17 cases were treated with steroid. In 2 patients with MPGN type I and 1 patient with DPGN, the treatment resulted in normalization of serum C3 level and urinary abnormalities and improvement of histological findings. In 3 patients with DPGN, urinary abnormalities and hypocomplementemia have been persisted and histological findings changed to those of MPGN type I. Thus, DPGN with hypocomplementemia seems to be an early stage of MPGN type I.

Familial progressive renal tubulopathy.

We report herein data on 6 male patients with progressive tubulopathy. These patients belonged to two families: the propositus, his father, a paternal first cousin, two paternal uncles, and a maternal uncle. A 7-year-old proband had mild proteinuria (1 g/day), consisting of beta 2-microglobulin, alpha 1-microglobulin and lysozyme, and aminoaciduria. Glycosuria and acidosis were absent. A 38-year-old father had mild proteinuria (2 g/day), including low-molecular-weight protein. Hypokalemia, hypophosphatemia, glucosuria, phosphaturia, aminoaciduria, and reduced urinary concentrating ability were also present. The other 4 affected family members also had low-molecular-weight proteinuria, detected by screening for beta 2-microglobulin. In addition, there were several abnormalities; aminoaciduria in all 6, phosphaturia in 4 of 6, hypercalciuria in all 6 and glycosuria in 2 of 6 patients. Tubular dysfunction was more severe in the older subjects, hence, the disease seems to progress with age. Familial low-molecular-weight proteinuria is apparently a progressive disease linked to a X-linked or to an autosomal dominant inheritance.

[The influence of exercise loading for a long period on the renal function of the children with mesangial proliferative glomerulonephritis].

We have studied the influence of exercise on renal function in chronic glomerulonephritis with mesangial proliferation. The mesangial proliferative glomerulonephritis consisted of (1) IgA nephropathy (Mild group), (2) IgA nephropathy (Moderate group), (3) diffuse proliferative glomerulonephritis = DPGN (Mild group), were divided 2 groups between (A) exercise loading groups and (B) control groups, respectively. The period of observation was one or one year 6 months. None of cases deteriorated in the renal function during the period of observation were found in the exercise loading groups. The prescription of exercise for permits with mesangial proliferative glomerulonephritis indicates approximately 130 values of %BMR, which is estimated by calorie counter.

[Growth of the aortic anastomosis in puppies--comparison of monofilament suture materials, whether absorbable or nonabsorbable, and of suture techniques, whether continuous or interrupted].

This study compared the growth of vascular anastomoses performed with either polypropylene or polydioxanone sutures and with either continuous running suture or interrupted suture technique. Primary end-to-end anastomoses of the infrarenal aorta were performed in 38 puppies. Nineteen were performed with 5-0 polypropylene sutures; in ten all sutures were placed in continuous fashion, and in nine in interrupted fashion. The other nineteen were performed with 5-0 polydioxanone sutures; in ten the sutures were placed in continuous fashion, and in nine in interrupted fashion. The animals were subjected to the repeated aortograms at 2, 4, 8 weeks, 6 months and 1 year following operation. Each abdominal aorta was subjected to burst test, and pathological examination. All anastomoses were patent and tolerated burst-test (300 mmHg). Neither aneurysm nor dilatation of anastomotic site was observed. Anastomotic area was significantly smaller and more stenotic in the continuous polypropylene suture group than in other three groups at 8 weeks, 6 months and 1 year following operation. There was no significant difference among these three groups. No suture materials were observed in the polydioxanone suture groups after 6 months following operation. This study suggests that polydioxanone suture will be useful for the repair of cardiovascular anomalies where growth of the suture line is required.

[Effect of superoxide dismutase on serum sickness nephritis].

Antiinflammatory effect of recombinant human Cu, Zn superoxide dismutase (SOD) was studied in Wistar rats with serum sickness nephritis induced by egg albumin injection. Different dosages of SOD were given intramuscularly in nephritis rats as follows: 0 (group A), 2 (group B), 10 mg/kg/day (group C). Control rats were given 10 mg/kg/day of SOD. On day 52, histopathological examinations of the kidney were performed in all animals. Urinary albumin was 0.35 +/- 0.21, 0.24 +/- 0.14, 0.34 +/- 0.28 and 0.41 +/- 0.21 mg/day in group A, B, C and control, respectively on day 0, and 33.0 +/- 21.5, 1.52 +/- 0.54, 2.55 +/- 1.67 and 0.21 +/- 0.02 mg/day in group A, B, C and control, respectively on day 52. Daily administration of SOD significantly suppressed urinary albumin excretion (A vs B & C, P less than 0.05). Numbers of nucleus per one glomeruli in rats were 119 +/- 3.6, 76.3 +/- 6.7, 71.1 +/- 8 and 65.5 +/- 3.3 in group A, B, C and control, respectively (A vs B & C, p less than 0.01). The glomerular damage in serum sickness nephritis which was potentially induced by free oxygen radicals, would be prevented by the administration of SOD.

Prognostic significance of alpha-1-antitrypsin in early stage of colorectal carcinomas.

We have previously shown that human colorectal carcinoma cell lines, RCM-1 and CoCM-1, synthesize alpha-1-antitrypsin (alpha 1-AT) in culture. We have studied immunohistochemically the incidence of alpha 1-AT on histologic sections from paraffin-embedded tissues of surgically resected colorectal carcinomas and their metastatic foci, polypectomized adenomas, and normal mucosae. alpha 1-AT was detected in 89 (61%) of 145 carcinomas (including 14 carcinomas in adenoma), and 12 (39%) of 31 adenomas. But only 2 (4%) of 55 normal colorectal mucosae were positive for alpha 1-AT. In metastatic tumor cells of colorectal carcinomas in lymph nodes and other organs, alpha 1-AT positivity was 60% and 82%, respectively. The incidence of alpha 1-AT was markedly higher in advanced adenocarcinomas than in early ones and more frequent in adenocarcinomas of right side (including transverse colon) than those of left side and rectum, regardless of their histological malignancy grades. In mucinous carcinomas the frequency was greater (8 of 9 cases) than in conventional adenocarcinomas. Clinical follow-up of the patients with colorectal carcinomas suggested that alpha 1-AT positivity in Dukes' stage A/B tends to correlate with unfavorable prognosis irrespective of the grade of histologic differentiation of carcinoma, but there is no significant relation in Dukes' stage C/D. Our findings suggest that alpha 1-AT in colorectal carcinoma is related to the invasive and metastatic capacity. It may thus serve as a biologic marker for prognosis of colorectal carcinomas at relatively early stages (Dukes' stage A/B).

Asymptomatic low molecular weight proteinuria: studies in five patients.

Asymptomatic low molecular weight proteinuria, a disease recently reported by Suzuki et al. [1985], was found in five boys, two pairs of brothers and a sporadic patient aged 3 to 11 years. Their urinary proteins contained 56% to 67% of proteins of less than 40,000 mol wt, defined as low molecular weight proteins by Suzuki et al. [1985], an indication that proximal tubular reabsorption of these proteins is impaired in these patients. Their glomerular function tests and intravenous urography were normal. An attempt was made to identify urinary low molecular weight proteins in these patients, using Western blotting analysis of the protein bands separated by sodium dodecylsulfate polyacrylamide gel electrophoresis. All five proteins tested were detected: alpha 1-acid glycoprotein (mol wt 44,000), alpha 1-microglobulin (mol wt 33,000), retinol-binding protein (mol wt 21,000), lysozyme (mol wt 14,000), and beta 2-microglobulin (mol wt 11,800). The latter two proteins had been identified in the disease by other means by Suzuki et al. [1985], while the other three were newly identified. Light microscopic studies of renal biopsy specimens from these patients revealed in three of four patients tested focal global or segmental glomerular sclerosis with scattered intratubular casts and focal tubular atrophy. Immunofluorescence staining of the renal biopsy specimens for the five proteins revealed some in the lumens of the proximal tubules and in the casts in the distal or collecting tubules, while only retinol-binding protein was found in the epithelial cytoplasm of the proximal tubules.

Primary malignant thymoma in a 6-year-old boy.

Although not uncommon in adults, thymomas are the least common mediastinal tumors in children. The behavior of these tumors in children is partially distinct with a much more rapid course and a poor prognosis. A symptom-free 6-year-old boy was treated for malignant thymoma detected incidentally on a chest X-ray in a school mass examination. At operation, the tumor was found to have already invaded the surrounding tissue. Complete removal at the base of the invasive tumor is the treatment of choice.