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Yuichiro Yamashiro

Publications and source records attributed to Yuichiro Yamashiro.

69 records · Page 4Linked to original sources
PubMed2002

Granulocyte colony-stimulating factor directly affects human monocytes and modulates cytokine secretion.

OBJECTIVE: Recent reports have indicated that monocytes express receptors for the granulocyte colony-stimulating factor (G-CSF). The direct effects of G-CSF on cytokine secretion in monocytes were examined. MATERIALS AND METHODS: A monocytic cell line NOMO-1 that secretes multiple cytokines upon stimulation with lipopolysaccharide (LPS) was used. Normal human monocytes were purified by negative selection using magnetic beads. Cells pretreated with or without G-CSF were stimulated with LPS, and the subsequent concentrations of cytokines and chemokines in supernatants were determined by sandwich enzyme-linked immunosorbent assay. RESULTS: NOMO-1 cells were found to express receptors for G-CSF. Although G-CSF stimulation did not induce cytokine secretion, pretreatment with G-CSF significantly attenuated LPS-stimulated secretion of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin (IL)-12 in NOMO-1 cells. Simultaneously, however, G-CSF pretreatment apparently enhanced LPS-induced secretion of IL-10 and monocyte chemoattractant protein-1, whereas secretions of IL-1beta, IL-6, and IL-8 were unaffected. When normal human monocytes from healthy volunteers were similarly examined, marked individual variations in LPS-induced secretion of cytokines were observed. Although some exceptions exist, a similar tendency as to the effects of G-CSF treatment on cytokine secretions as that in NOMO-1 cells was observed in human monocytes. CONCLUSIONS: Our data suggest that G-CSF directly affects monocytes and modulates their cytokine secretion. NOMO-1 cells can provide an alternate model for in vitro culture of monocytes to investigate the effects of G-CSF on cytokine secretion by these cells.

Cell Line↗
PubMed2002

Retinal neurodevelopmental assessment with electroretinogram in patients with biliary atresia.

BACKGROUND: To evaluate the effect of n-3 polyunsaturated fatty acid (PUFA) deficiency on the development of retinal function in children with biliary atresia (BA), we examined serum fatty acid levels and performed electororetinogram (ERG) in patients with BA. METHODS: The study group was composed of one male and four female BA patients (8-14 years) with serum bilirubin levels ranging from 0.40 to 1.48 mg/dL. All of the subjects were born as full-term infants. The fatty acid composition of total lipids in serum was analyzed by gas chromatography before the Kasai operation, approximately 10 months after the Kasai operation, and at the time of the ERG study. The ERG was recorded using corneal contact lens electrodes. RESULTS: Two of the five patients showed decreased levels of arachidonic acid and docosahexaenoic acid (DHA) before and after the operation, but no abnormal findings on ERG were detected in these patients. The other three patients had decreased levels of alpha-linolenic acid or DHA after the operation, but again, no abnormalities were found on ERG. CONCLUSION: These results suggest that insufficiencies of DHA and other n-3 PUFA in full-term infants might not have an influence on later ERG results.

Adolescent↗
PubMed2002

Mizoribine treatment for childhood IgA nephropathy.

BACKGROUND: There is currently no established therapy for childhood IgA nephropathy (IgAN). Mizoribine, a newly developed immunosuppressive agent characterized as a safe and well-tolerated drug, has been widely used in diverse conditions. Our preliminary study demonstrated that mizoribine could reduce the amount of proteinuria in children with IgAN. The present study was conducted to confirm this finding. METHODS: Ten children with IgAN (median age 13.5 years) of moderate histological severity were enrolled. None of them had been previously treated by immunosuppressants. Mizoribine was administered orally for a median period of 20.5 months. We compared the urinary protein excretion expressed as the ratio of urinary protein to urinary creatinine (UP/UC) and the hematuria evaluated as the level of occult blood by dip-stick (OB score). Renal histology was also examined in three patients using paired biopsy specimens obtained both before and after treatment. We performed blood examinations regularly to monitor the toxicity and plasma concentration of mizoribine. RESULTS: The median observation period was 44.5 months, consisting of a median 13.0 months before therapy, 20.5 months during therapy and 12.0 months after therapy. Significant reductions in both UP/UC and OB score were induced by mizoribine (P < 0.05). Renal mesangial proliferation was also improved. Plasma peak levels of mizoribine varied from 0.30 microg/mL to 1.23 microg/mL and were not associated with its effectiveness. No adverse effects were observed during the therapy, although a slight decrease in leukocyte count was noted. CONCLUSION: Mizoribine can be an alternative drug for childhood IgAN with moderate severity because it results in a significant reduction of proteinuria and hematuria with histological improvement and causes far fewer complications compared to the conventional immunosuppressants.

Adolescent↗
PubMed2002

Emergence of clarithromycin-resistant Helicobacter pylori (CRHP) with a high prevalence in children compared with their parents.

BACKGROUND: Clarithromycin-resistant Helicobacter pylori (CRHP) is increasing worldwide. Clarithromycin resistance in H. pylori from familial members has not been investigated. MATERIALS AND METHODS: Biopsy specimens were taken from 13 families living in Tokyo, Yokohama, and Niigata between 1998 and 2001. Drug resistance was tested with the replica plating method. The minimum inhibitory concentrations of antimicrobial agents for H. pylori strains were determined by the agar dilution method. Molecular analyses of H. pylori strains were performed by ribosomal RNA gene restriction pattern analysis. The DNA region, associated with clarithromycin resistance, was analyzed by PCR and sequencing. RESULTS: Helicobacter pylori strains isolated from a 5-year-old-son displayed clarithromycin resistance with a mutation (A --> G at position 2143) in the 23S ribosomal RNA, whereas H. pylori strains from his parents did not. DNA analyses revealed that the boy was infected with his father's strain. The boy had repeatedly developed otitis media and received clarithromycin since the age of 2 years. Studies on an additional 12 families demonstrated that clarithromycin resistance in the children's strains reached 42.9% and was significantly higher than those of H. pylori strains from their parents (0%) or from adult patients (11.1%) (p <.05). CONCLUSIONS: The rate of clarithromycin resistance in H. pylori strains from Japanese children was extremely high, in contrast to those from their parents or adult patients. Prior history of clarithromycin usage in a child suggested development of clarithromycin resistance in resident H. pylori, which was originated from a parent.

Adult↗
PubMed2002

Effects of parenteral lipid infusion on DNA damage in very low birth weight infants.

Very low birth weight (VLBW) infants are known to have poorly developed antioxidant system and may be at increased risk for radical damage. Previous studies have reported higher levels of lipid peroxide products in lipid emulsion used for parenteral nutrition. To examine the direct effects of parenteral lipid infusion on DNA damage in VLBW infants, we measured urinary 8-hydroxydeoxyguanosine (8-OHdG) levels in VLBW infants before, during, and after the parenteral lipid infusion. In both the lipid-infused and lipid-free groups, urinary 8-OHdG excretion levels at 14 days old were significantly (p < 0.01) lower than those at 2 and 7 days old. However, there were no significant differences in urinary 8-OHdG excretion levels between the lipid-infused and lipid-free groups at 2, 7, and 14 days old. Our results suggest that parenteral lipid infusion does not cause oxidative DNA damage, but irrespective of the infusion DNA damage during the first week of life is enhanced when compared with 14 days after birth in VLBW infants.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2002

Low prevalence of hypercalciuria in Japanese children.

BACKGROUND/AIM: There are several factors, such as race, age, sex, and geographical variations, associated with renal stone formation. Although it is known that the prevalence of urolithiasis in Japanese children is low, the reason remains obscure. We hypothesize that the low prevalence of urolithiasis is associated with the urinary calcium excretion. The aim of our study was to investigate the prevalence of hypercalciuria in Japanese children. METHODS: This investigation is a population-based school survey. A group of 529 healthy Japanese children was screened for hypercalciuria by measurement of the urinary Ca/Cr ratio using the morning fasting urine. In addition, the urinary Na/Cr ratio was also calculated for each subject. RESULTS: Hypercalciuria regarded as an urinary Ca/Cr value of more than 0.17 was noted only in 3 out of 529 children (0.6 %), while most cases (494/529, 93.4%) demonstrated hypocalciuria (urinary Ca/Cr <0.05). The mean urinary Ca/Cr value was 0.024 in all subjects combined. Linear regression analysis revealed a positive direct correlation between urinary Ca/Cr and Na/Cr values (rs = 0.14, p < 0.01). The urinary Ca/Cr ratio was not related to age in either sex. CONCLUSIONS: The present study demonstrates that the prevalence of hypercalciuria in Japanese children is low as compared with other countries, even though absorptive hypercalciuria and dietary hypercalciuria might be missed in this setting. This low prevalence of hypercalciuria may be associated with the lower prevalence of urolithiasis in Japanese children. As it is suggested that a low dietary intake of calcium and sodium may play some role in the low urinary calcium excretion, a randomized, controlled study comparing the efficacy of different modes of therapy, such as a low-calcium diet and/or a low-salt diet, might provide valuable information for the prevention of urolithiasis.

Calcium↗
PubMed2002

Effect of mizoribine on IL-6 release by peripheral blood mononuclear cells.

BACKGROUND/AIM: A novel immunosuppressant, mizoribine (MZB), has recently been reported to be effective in the treatment of IgA nephropathy (IgAN), although its mechanism of action remains unknown. This study was conducted to investigate whether the efficacy of MZB on IgAN is exerted by suppression of interleukin-6 (IL-6) release. METHODS: Peripheral blood mononuclear cells (PBMC) were collected from 4 children with IgAN (median age 13.0 years) and 4 control children (median age 5.2 years). PBMC were cultured with medium alone or medium with lipopolysaccharide (LPS), and then incubated with LPS and MZB. Culture supernatants were assayed for lL-6. RESULTS: IL-6 release was increased by LPS in all subjects. Although the median value was higher in IgAN patients (median increase in IL-6 release 1,298.1%) than in controls (median 489.2%), statistical significance was not reached (p > 0.05). 10 mg/ml of MZB suppressed the release of IL-6 in both IgAN patients (median decrease in IL-6 release 39.3%) and controls (median 43.2%), with statistical significance (p < 0.05 and p < 0.01, respectively). CONCLUSION: This study suggests that MZB could suppress IL-6 release in vitro and thus may exert its efficacy on IgAN.

Adolescent↗
PubMed2002

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Journal Article↗
PubMedDate not supplied

A fetal case of transient abnormal myelopoiesis with severe liver failure in Down syndrome: prognostic value of serum markers.

The authors recently encountered a lethal case of Down syndrome with transient abnormal myelopoiesis (TAM). Although the peripheral white blood cell count and blast cells had improved without specific treatment, the patient died of severe coagulopathy due to liver fibrosis when he was 5 years old. The prognosis of TAM with liver fibrosis was poor. The patient had high levels of N-terminal peptide of III procollagen, type IV collagen, and hyaluronic acid. These serum makers are noninvasive indicators of liver fibrosis and may be useful as prognostic indicators of TAM in Down syndrome.

Biomarkers↗