Chikahide Hori

Bone Mineral Status in Preterm-Born Children: Assessment by Dual-Energy X-Ray Absorptiometry

To elucidate the long-term consequences of osteopenia of prematurity, lumbar spinal bone mass was measured in 21 preterm-born children aged 3-4 years by dual-energy X-ray absorptiometry. Their mineral intake remained low during early life, and all 11 infants previously studied were osteopenic at term postconception. At the age of 3-4 years, however, all 21 children were found to have normal bone mineral content and density with slightly elevated serum osteocalcin levels. Our results show that in preterm-born children spontaneous resolution of lumbar spinal osteopenia occurs during early childhood.

Chronic erythropoietin treatment enhances endogenous nitric oxide production in rats

To examine the effect of chronic administration of recombinant human erythropoietin (rHuEPO) on endogenous nitric oxide (NO) activity, we treated Sprague-Dawley rats with rHuEPO (100 IU kg-1 or 300 IU kg-1) or a corresponding vehicle for 2 weeks, administered subcutaneously on alternate days. Treatment elicited increases in haematocrit and systolic blood pressure in a dose-dependent fashion. Simultaneous administration of NG-nitro-L-arginine methyl ester (L-NAME, 20 mg dl-1 of drinking water), but not aminoguanidine (400 mg dl-1), induced a further significant rise in blood pressure. The effect of L-NAME was inhibited by a large dose of L-arginine (2.0 g dl-1). Polycythaemia and hypertension induced by chronic rHuEPO therapy were associated with increased urinary NO2- and NO3- (NOx-) excretion, while co-administration of L-NAME, but not aminoguanidine, reduced NOx- excretion. Our results indicate that chronic rHuEPO treatment has a significant pressor effect, but induces a compensatory increase in the steady-state release of NO by constitutive NO synthase in normal rats. Such enhanced NO synthesis may act as a protective mechanism against the hypertensive effect of rHuEPO.

Age-Related Changes of Urinary Nitrite/Nitrate Excretion in Normal Children

We measured the urinary excretion of nitrite/nitrate, stable metabolites of nitric oxide, using the brucine method in 90 healthy normal children (47 boys and 43 girls), aged from 1.0 to 17.1 years, to establish the age-related normal range in children. The urinary nitrite/nitrate excretion was highest in the youngest children and decreased in an age-dependent manner to reach constant levels at about 12 years of age in both sexes. The data may be useful in identifying sick children with abnormal nitric oxide production.

Urinary nitrite/nitrate excretion in infancy: comparison between term and preterm infants

We measured urinary nitrite/nitrate (NOx-) excretion, an index of endogenous nitric oxide formation, in term and preterm infants aged 1 week and 1, 4, 7 months. In normal term infants, urinary NOx excretion increased from 1 week to 1 month and then decreased until 4 months where it stabilized thereafter. Urinary NOx- excretion in preterm infants was significantly higher compared with term infants at 1 week of age. This finding suggests that the nitric oxide pathway in preterm infants may be activated compared with term infants in early life. With the reference values obtained in this study, this urinary marker can now be used for identifying infants with abnormal nitric oxide production.

Ultrasonographic findings of acute tubulointerstitial nephritis.

Three children were diagnosed as having acute renal failure due to acute tubulointerstitial nephritis (TIN) associated with Yersinia pseudotuberculosis infection. The kidneys were observed ultrasonically during the disease course. The subjects presented with remittent fever, vomiting or diarrhea, and nonoliguric acute renal failure with sterile pyuria and tubular reabsorptive dysfunction. Ultrasound examination delineated marked enlargement of the kidneys with diffuse hyperechogenicity in the cortex, suggesting the diagnosis of TIN. The renal swelling was marked in the descending order of width, depth and length, respectively, and reached more than 200% in volume in 1 of the children who was examined at the culminating stage of acute renal failure. The enlarged kidneys reduced in size in parallel as the elevated serum creatinine levels decreased. However, the enlarged kidneys did not seem to return to their original sizes: the kidney size in 1 of the children remained well above the upper allowance limit of the body-height-related normals and in the other 2 they were only a little smaller than the upper limits. These ultrasound findings should help with the diagnosis and follow-up of the disease.

Ultrasonographic evaluation of bladder volume in children

Although ultrasound has been recently used to estimate bladder volume, several different formulae are used. We analysed the accuracy of ultrasound evaluation of bladder volume with an ultrasound scanner equipped with a videocassette recorder. We determined three dimensions of the bladder, i.e. depth (D), height (H) and width (W) by reviewing videotapes in 53 children. D×H×W (DHW) showed a good linear relationship with actual bladder volume (r=0.96). Estimation of bladder volume by the regression equation gave errors of 12.5±8.6% (mean±SD) with errors above 25% in only 6% of children. Estimation of the volume by simply multiplying DHW by a correction factor of 0.80 gave a greater error of 18.9±14.0% (P<0.001) with errors above 25% in 24% of children. Thus, the use of the formula volume (ml)=DHW (cm3)×0.68+4 was sufficiently accurate in the ultrasound estimation of bladder volume in children.

Urine microscopy on a counting chamber for diagnosis of urinary infection

Several quantitiative methods of urine microscopic examination for bacteriuria and pyuria on a blood cell counting‐chamber have been found reliable for the diagnosis of urinary tract infection (UTI). However, no one technique has become popular or widely used because of laborious procedures associated with the method. We investigated the usefulness of microscopic examination of uncentrifuged urine on disposable counting‐chambers.

Lipoma on surface of centroparietal lobes

A 4-year-old Japanese boy with an intracranial lipoma above the surface of the left centroparietal lobes is reported. Paresthesia occurred in the right lower extremity. This symptom continued for 30 min and recurred several times a day. Three weeks after onset, the paresthesia disappeared spontaneously. Ten months after onset, generalized tonic seizures occurred. Routine cranial computed tomography at onset revealed no remarkable lesion, but subsequently full scans, including the slice at the top of the cerebrum, revealed low-density areas on the surface of the left centroparietal lobes. T1-weighted magnetic resonance imaging revealed a hyperintense area in the same regions. The intensity of these areas was decreased by the fat saturation technique; therefore, an intracranial lipoma at a very rare site was diagnosed.

Significance of ACE genotypes and medical treatments in childhood focal glomerulosclerosis.

Backtround: There is little information on the significance of angiotensin-converting enzyme (ACE) genotypes and medical treatments in children with primary focal segmental glomerulosclerosis (FSGS). Methods: A multicenter retrospective study was performed on the role of ACE genotypes and medical treatments in 43 Japanese children with FSGS (20 males and 23 females), including 17 children who progressed to end-stage renal failure during the mean observation period of 6.9 ± (SD) 5.0 years. Results: The incidence of the D allele of the ACE gene was higher in the whole group of 43 children with FSGS and in a subgroup of 28 steroid-resistant FSGS children (p < 0.05) than in the 130 children of the healthy control group (0.48, 0.48, and 0.33, respectively). ACE genotypes did not affect renal survival in the whole FSGS group nor in the steroid-resistant subgroup. Among the 28 steroid-resistant children, treatment with ciclosporin was effective in delaying the development of end-stage renal failure (p = 0.044), independently of other treatment regimens. Conclusion: The present study of Japanese children with FSGS showed that the D allele of the ACE gene is associated with the development of FSGS, but not associated with the progression of FSGS which was greatly ameliorated with ciclosporin, irrespective of ACE genotypes.

Endothelin subtype A receptor antagonist induces osteopenia in growing rats

Previous studies suggested that endothelin (ET) peptides are involved in bone metabolism. We examined the effects of long-term blockade of the ET(A) receptor, a receptor subtype primarily involved in the anabolic actions of ET, on bone mineral status in growing rats. Eight-week-old rats injected intraperitoneally with FR139317 50 mg/kg body weight, a specific ET(A) receptor antagonist, for 2 or 4 weeks were compared with control rats injected with vehicle only. Treatment with FR139317 caused a significant decrease in bone mass in the lumbar spine as determined by dual-energy x-ray absorptiometry (DXA). FR139317-induced osteopenia was associated with a significant decrease in the serum osteocalcin concentration but no change in the urinary excretion of pyridinium cross-links of collagen. Our findings indicate that long-term blockade of the ET(A) receptor reduces bone formation and induces osteopenia in growing rats. Our results suggest that ET produced by vascular endothelial cells plays an important role in bone growth and metabolism in vivo.