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K Ozono

Publications and source records attributed to K Ozono.

At least 19 recordsLinked to original sources
PubMed2006

Lipocalin-type prostaglandin D synthase (beta-trace) is upregulated in the alphaB-crystallin-positive oligodendrocytes and astrocytes in the chronic multiple sclerosis.

Lipocalin-type prostaglandin D synthase (L-PGDS), which is mainly synthesized in leptomeningeal cells and oligodendrocytes (OLs) in rodents and humans, is secreted into the human cerebrospinal fluid (CSF) as beta-trace. L-PGDS protects OLs and neurones against apoptosis in twitcher mice, a murine model of Krabbe's disease, and is the second only to a stress protein, alphaB-crystallin, as the most abundant gene product upregulated in the demyelinating focus of multiple sclerosis (MS). Here we report that although the CSF level of L-PGDS is not increased in MS patients, L-PGDS is increased in the white matter of MS patients, especially in the shadow plaque as compared with the normal white matter. L-PGDS immunoreactivity was intensely expressed in OLs within the shadow plaques and in hypertrophied astrocytes within the chronic plaques of MS patients. Both L-PGDS-positive OLs and astrocytes expressed a stress protein, alphaB-crystallin. These results suggest that the upregulation of L-PGDS occurs in OLs and astrocytes as a stress reaction.

Adult↗
PubMed2002

Novel mutations in the a3 subunit of vacuolar H(+)-adenosine triphosphatase in a Japanese patient with infantile malignant osteopetrosis.

A case of infantile malignant osteopetrosis is described. The patient died from respiratory hemorrhage at 7 months of age despite treatment that included high doses of active vitamin D and administration of interferon-gamma. A postmortem examination revealed the presence of many osteoclasts in the bone, which lacked ruffled borders. This observation was consistent with the histology of bone reported in Atp6i-knockout mice, which lack the gene encoding the a3 subunit of vacuolar-type H(+)-adenosine triphosphatase (ATPase). Sequence analysis of the TCIRG1 gene encoding the a3 subunit revealed two novel mutations: a deletion/insertion mutation in exon 9 and a T-to-C transition at the splice donor site of intron 19. The former mutation caused a frame shift and premature stop codon. The latter was associated with abnormal splicing, which was confirmed by sequencing the products amplified by reverse transcription-polymerase chain reaction (RT-PCR), using total RNA from the liver specimen as template. Although several mutations in the TCIRG1 gene in infantile malignant osteopetrosis have been reported in other populations, this is the first case of a Japanese patient with a mutation identified in this gene. These results support the important role of the subunit in the function of the proton pump.

Codon, Terminator↗
PubMed2002

Glu274Lys/Gly309Arg mutation of the tissue-nonspecific alkaline phosphatase gene in neonatal hypophosphatasia associated with convulsions.

We describe a patient diagnosed with lethal perinatal hypophosphatasia with a unique clinical presentation of convulsions that responded to vitamin B6. Genomic DNA sequence analysis of the tissue-nonspecific alkaline phosphatase (TNSALP) gene revealed two missense mutations: a G-to-A transition resulting in a Glu to Lys at codon 274 (E274K), and a G-to-C transversion resulting in a Gly to Arg at codon 309 (G309R). The first mutation was maternally transmitted and was previously characterized as a moderate one, whereas the latter was paternally transmitted and has not been previously reported. Phenotype/genotype correlation indicates that G309R is a deleterious mutation that can lead to seizures and a lethal outcome, as was demonstrated in our patient.

Alkaline Phosphatase↗
PubMed2001

Loss of the SEDL gene product (Sedlin) causes X-linked spondyloepiphyseal dysplasia tarda: Identification of a molecular defect in a Japanese family.

A 23-year-old man was diagnosed as having X-linked spondyloepiphyseal dysplasia tarda (SEDT; MIM 313400) based on his disproportionately short trunk, short stature, characteristic radiological features of the spine (posterior hump, end plate sclerosis, and disc space narrowing) and the hips (short and thick femoral necks), and positive family history. This Japanese family was found to have an intragenic deletion flanking intron 2 and exon 3 of the SEDL gene that not only included the 5' untranslated region but also the coding sequence for the first methionine through the 25th alanine. This mutation was present in the proband and his unaffected mother (a heterozygote), but not in an unaffected sister and an unaffected uncle. The nature of the mutation predicted that the SEDL protein (Sedlin) was not produced in the proband, indicating that loss of Sedlin caused SEDT.

Adult↗
PubMed2001

Receptor activator of nuclear factor kappaB ligand (RANKL) is a key molecule of osteoclast formation for bone metastasis in a newly developed model of human neuroblastoma.

Neuroblastoma originates from neural crest cells and is the most common extracranial solid tumor in childhood. Bone metastasis in neuroblastoma is an unfavorable prognostic factor even with intensive therapy. In the present study, we screened four cell lines of human neuroblastoma (NB-1, NB-16, NB-19, and NH-6) for tumorigenicity and metastatic capacity in nude mice and found that NB-19 cells caused osteolytic lesions after s.c. injection into mice. To detect micrometastases in the host tissue, we performed two kinds of PCR-based metastasis assays: (a) genomic PCR assay using the primers for human genome-specific Alu sequence; and (b) reverse transcription-nested PCR assay that detects the expression of tyrosine hydroxylase, a marker specific for neuroblastoma. The results of these PCR assays revealed the colonization of human neuroblastoma cells in the bone marrow of the mice that had received the s.c. injection of NB-19 cells. Because osteoclastic bone resorption has been reported to play important roles in osteolysis in some cancers such as breast cancer, we next examined the osteoclast (OC)-inducing activity of NB-19 cells using a coculture system in which NB-19 cells were cultured with murine bone marrow cells containing OC precursors and stromal cells. NB-19 cells induced tartrate-resistant acid phosphatase-positive multinucleated OC-like cells without requirement of 1,25-dihydroxyvitamin D3 or other osteoclastogenic stimulators. To investigate the factors involved in the osteoclastogenesis in the coculture of mouse marrow cells and NB-19 cells, we performed reverse transcription-PCR analysis and revealed the increased expression of receptor activator of nuclear factor kappaB ligand (RANKL) in the coculture compared with the culture of bone marrow cells alone. Interleukin-1alpha and cyclooxygenase-2 expression in the murine marrow cells was also increased in the presence of NB-19 cells. To further study the role of RANKL in the OC-like cell formation in the coculture of NB-19 cells and murine marrow cells, an expression vector encoding the active portion of the murine osteoprotegerin, which is the native inhibitor of RANKL action, was constructed and introduced into COS-7 cells. The conditioned media of the COS-7 cells transfected with the osteoprotegerin expression vector effectively blocked OC-like cell formation in the coculture of the bone marrow cells and NB-19 cells. These results suggested that in the bone microenvironment of NB-19-bearing mice, the stimulated expression of RANKL plays an important role in OC formation, leading to osteolytic bone metastasis.

Acid Phosphatase↗
PubMed2001

Hypophosphatemic rickets accompanying McCune-Albright syndrome: evidence that a humoral factor causes hypophosphatemia.

McCune-Albright syndrome (MAS) is sometimes complicated by hypophosphatemia. However, it remains unclear whether a humoral factor is associated with the cause of hypophosphatemia. We isolated cells with mutations of the Gsalpha gene from fibrous bone dysplasia tissues of two MAS patients (MAS cells). Severe combined immunodeficiency (SCID) mice were subjected to experiments using from one of these cells patients. Effects of conditioned media (CM) isolated from MAS cells (MAS-CM) on phosphate transport were investigated by using rat renal slices, the renal cell line OK-B, rat intestinal rings and the human intestinal cell line Caco-2. In addition, the effects of MAS-CM on human sodium-dependent phosphate transporter (NPT2) gene promoter activity expression were investigated in the renal cell line OK-B2400 and were compared with the effects of CM isolated from a patient with oncogenic hypophosphatemic osteomalacia (OHO). MAS cells caused significant hypophosphatemia (P < 0.05) and elevated serum alkaline phosphatase activity (P < 0.05) in SCID mice. The MAS-CM significantly inhibited phosphate uptake in everted intestinal rings (P < 0.01), whereas it had no effect on glucose uptake. The MAS-CM had no effect on either phosphate uptake in the kidney or NPT2 gene promoter activity. In contrast, the CM of the OHO patient significantly inhibited phosphate uptake and NPT2 gene promoter activity. These results indicate that the humoral factor derived from fibrous dysplasia cells of the MAS patient is different to that from OHO patients, because the humoral factor from the MAS patient inhibited phosphate transport not in the kidney but in the intestine.

Adolescent↗
PubMed2001

A novel activating mutation (C129S) in the calcium-sensing receptor gene in a Japanese family with autosomal dominant hypocalcemia.

Autosomal dominant hypocalcemia can be caused by activating mutations of the calcium-sensing receptor (CaSR) gene. We experienced two patients (proband and her daughter) with hypocalcemia caused by a missense mutation of the CaSR gene. The proband, aged 25, showed hypocalcemia and hypoparathyroidism from infancy. She had been diagnosed as having idiopathic hypoparathyroidism and had been treated with calcitriol. She gave birth to a female infant at age 24 years. Her daughter was found to have hypocalcemia (Ca, 6.6mg/dl), without seizure or tetany, when she was 7 months old. DNA analysis of their CaSR genes showed a novel heterozygous mutation at codon 129 (TGC-to-AGC) with substitution of cysteine for serine (C129S). Familial examination revealed that this mutation had occurred de-novo in the proband. Wild-type and niutant (C129S) CaSR cDNA were transfected into HEK293 cells, and intracellular calcium concentrations were measured with a fluorescent calcium indicator. HEK cells transfected with the C129S mutant CaSR gene showed a larger increase in intracellular calcium concentration in response to the change in the extracellular calcium concentration than HEK cells transfected with the wild-type receptor. We conclude that the C129S mutation in the CaSR gene observed in these patients causes autosomal dominant hypocalcemia.

Adult↗
PubMed2001

Synthesis and evaluation of A-ring diastereomers of 1alpha,25-dihydroxy-22-oxavitamin D3 (OCT).

A-ring diastereomers of 1alpha,25-dihydroxy-22-oxavitamin D3 (OCT) (2), 3-epi-1alpha,25-dihydroxy-22-oxavitamin D3 (3-epiOCT) (3) and 1,3-diepi-1alpha,25-dihydroxy-22-oxavitamin D3 (1,3-diepiOCT) (4) were synthesized by the convergent method. In vitro binding affinity for rat vitamin D binding protein and calf-thymus vitamin D receptor, differentiation-inducing activity on HL-60 cells, and transcriptional activity of 3-epiOCT (3) and 1,3-diepiOCT (4) were evaluated in comparison with OCT (2), 1-epi-1alpha,25-dihydroxy-22-oxavitamin D3 (1-epiOCT) (5) and 1alpha,25-dihydroxyvitamin D3 (1).

Animals↗
PubMed2001

Skeletal development of achondroplasia: analysis of genotyped patients.

BACKGROUND: Achondroplasia is a skeletal dysplasia caused by substitution of arginine for glycine at codon 380 (G380R) mutation of the fibroblast growth factor receptor 3. To date, the developmental course of the phenotype (short stature and skeletal characteristics) has not been clarified in the genotyped population. METHODS: The relationship between age and clinical data (height, arm span and measurements of skeletal radiographs) were statistically analyzed from 27 achondroplasia patients with the G380R genotype. RESULTS: The height standard deviation score had positive correlation and decreased with age, while span-to-height ratio did not. Among measurements of skeletal radiographs, the pelvic index, which represents the squared pelvis deformity, were correlated and increased with age. However, interpedicular distance of the first and fourth lumbar vertebrae (L1:L4) ratio as an index for the caudally narrowed pattern of the lumbar spinal canal and fibula-to-tibia ratio for the disproportionally long fibulae were not correlated and did not increase with age. CONCLUSION: In making a clinical diagnosis of achondroplasia in early infancy, it should be noted that short stature and squared pelvis deformity are not prominent.

Achondroplasia↗
PubMed2001

Role of advanced glycation end products in adynamic bone disease in patients with diabetic nephropathy.

Adynamic bone disease and elevated serum levels of advanced glycation end products (AGEs) often are found in patients with renal failure caused by diabetic nephropathy. To clarify the role of AGEs in adynamic bone disease, we investigated the effect of these substances on cultured human osteoblasts and parathyroid cells. After 72 hours of incubation with AGEs-bovine serum albumin (BSA) (1,000 microgram/mL), there was significant inhibition of the synthesis of type I collagen and osteocalcin in response to stimulation with 10(-10) to 10(-8) M of 1,25-dihydroxycholecalciferol. In a human osteoblastic cell line (MG 63), AGEs-BSA did not affect human osteocalcin promoter activity. In human parathyroid cells, a receptor for AGEs was detected by reverse-transcriptase polymerase chain reaction. Incubation with AGEs-BSA for 48 hours significantly inhibited parathyroid hormone secretion in response to a low calcium concentration of 0.81 mM (P < 0.01). In HEK-293 cells, expressing calcium-sensing receptors, the same AGE concentration caused a significant potentiation of the extracellular Ca(2+) induced-intracellular calcium concentration after 24 and 48 hours of incubation (P < 0.05 and P < 0.01). These data suggest that AGEs are involved in the pathogenesis of adynamic bone disease by inhibiting osteoblastic activity and by inhibiting parathyroid hormone secretion in response to hypocalcemia.

Calcitriol↗
PubMed2001

Antagonistic Actions in Vivo of (23S)-25-Dehydro-1alpha-Hydroxyvitamin D(3-)26,23-Lactone on Calcium Metabolism Induced by 1alpha,25-Dihydroxyvitamin D(3).

The vitamin D analog, (23S)-25-dehydro-1alpha-hydroxyvitamin D(3)-26,23-lactone (TEI-9647), is an antagonist of the 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] nuclear receptor (VDR)-mediated differentiation of human leukemia (HL-60) cells. To clarify whether TEI-9647 could function as an antagonist of 1alpha,25(OH)(2)D(3) in vivo, we investigated in vitamin D-deficient (-D) rats the effects of single doses of TEI-9647 on several parameters of calcium metabolism modulated by 1alpha,25(OH)(2)D(3). TEI-9647 (50 microgram/kg iv) acting alone slightly, but significantly, stimulated intestinal calcium transport (ICA) and bone calcium mobilization (BCM) only at 8 h, but not at 24 h. In contrast, TEI-9647 dose-dependently inhibited ICA and BCM stimulated by an iv dose of 0.25 microgram/kg 1alpha,25(OH)(2)D(3) after 24 h, but not after 8 h. With respect to serum PTH levels, the administration of either TEI-9647, 50 microgram/kg, or 1alpha,25(OH)(2)D(3), 0.25 microgram/kg, began to decrease the circulating levels by 4 h, which reached a nadir 24 h after administration. But, when TEI-9647 and 1alpha,25(OH)(2)D(3) were simultaneously administered to -D rats, the TEI-9647 dose-dependently reversed the inhibition of PTH secretion caused by 1alpha,25(OH)(2)D(3), 0.25 microgram/kg, at 8 and 24 h after the treatment. In separate experiments, the daily iv administration of 20 microgram/kg of TEI-9647 alone to +D rats for 2 weeks resulted in no significant changes in the prevailing serum Ca(2+) concentration. But doses of 1-20 microgram/kg of TEI-9647 in combination with 0.5 microgram/kg of 1alpha,25(OH)(2)D(3), for 2 weeks, dose-dependently and significantly suppressed the serum calcium concentration increase caused by the 1alpha,25(OH)(2)D(3). Collectively, these results show that TEI-9647 acting alone displays in vivo weak agonistic actions, but when administered in combination with 1alpha,25(OH)(2)D(3), is a potent antagonist of three genomic-mediated calcium metabolism parameters. We conclude that TEI-9647 can also function as an antagonist of 1alpha,25(OH)(2)D(3) in vivo in the rat.

Animals↗
PubMed2001

Hydroxylases involved in vitamin D metabolism are differentially expressed in murine embryonic kidney: application of whole mount in situ hybridization.

In this study we examined the expression of 25-hydroxyvitamin D-1alpha-hydroxylase (1alpha-hydroxylase) and 25-hydroxyvitamin D-24-hydroxylase (24-hydroxylase) by RT-PCR and whole mount in situ hybridization using organ culture of kidney taken from mouse embryo. First, the kidneys of mouse embryo at 11.5-17.5 days gestation were cultured in the presence or absence of forskolin and 1,25-dihydroxyvitamin D(3) [1alpha,25-(OH)(2)D(3)]. Forskolin and 1alpha,25-(OH)(2)D(3) induced the expression of 1alpha-hydroxylase and 24-hydroxylase, respectively, in a dose- and time-dependent manner. In the absence of stimulants, the expression of 1alpha-hydroxylase and 24-hydroxylase was detected from days 13.5-17.5 gestation. The expression of vitamin D receptor and megalin was detected from days 13.5 and 11.5, respectively. Next, signals for the expression of either 1alpha-hydroxylase or 24-hydroxylase were detected by whole mount in situ hybridization in kidney explants taken from embryo at 15.5 days gestation after the appropriate stimulation. However, the localization of signals differed between the two enzymes; 1alpha-hydroxylase messenger RNA was expressed in the inner area of the kidney explants, whereas 24-hydroxylase messenger RNA was expressed in the surface area. The expression of both hydroxylases was restricted to the epithelium of developing renal tubules. The pattern of megalin expression was similar to that of 1alpha-hydroxylase expression. To confirm the difference in distribution of 1alpha-hydroxylase and 24-hydroxylase transcripts, the explants were hybridized with probes for both 1alpha-hydroxylase and 24-hydroxylase using double labeling techniques after simultaneous stimulation with forskolin and 1alpha,25-(OH)(2)D(3), resulting in the detection at different locations of positive signals for the two enzymes. These results suggest that the expression of 1alpha-hydroxylase is induced in a distinct epithelium of renal tubules from that of 24-hydroxylase even at the early stage of kidney development before glomerulogenesis.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed2001

Hyperintensity of posterior pituitary on MR T1WI in a boy with central diabetes insipidus caused by missense mutation of neurophysin II gene.

We present a 10-year old boy with central diabetes insipidus (CDI) showing hyperintensity in a normal-sized posterior pituitary on magnetic resonance (MR) T1-weighted image (T1WI). He complained of nocturnal enuresis and polyuria. Daily urine volume increased to 4 to 5 L, and AVP plasma level was very low. Polymerase chain reaction (PCR)-amplified exons of the arginine vasopressin (AVP)-neurophysin (NP) II gene were sequenced. Nucleotide-1884 guanine in Exon 2 was substituted with thymine, which induced a substitution of glycine for valine at amino acid position 65 in the NP II moiety. However, MR imaging showed hyperintensity in the posterior pituitary on T1WI. These results suggest that the MR findings of the posterior pituitary in CDI may vary.

Child↗
PubMed2001

Conflicting actions of parathyroid hormone-related protein and serum calcium as regulators of 25-hydroxyvitamin D(3)-1 alpha-hydroxylase expression in a nude rat model of humoral hypercalcemia of malignancy.

In patients with humoral hypercalcemia of malignancy (HHM), serum levels of 1,25-dihydroxyvitamin D (1,25(OH)(2)D) are generally low, although the pathophysiology of the impaired vitamin D metabolism is not fully understood. In the present study, we have investigated vitamin D metabolism in our newly developed rat model of HHM in which a human infantile fibrosarcoma producing parathyroid hormone-related protein (PTHrP), named OMC-1, was inoculated s.c. into athymic nude rats. In OMC-1-bearing rats, the serum concentration of 1,25(OH)(2)D was markedly reduced when the animals exhibited severe hypercalcemia (Ca > or =15 mg/dl), while it was rather elevated in those with mild hypercalcemia. To further examine whether serum Ca levels affect 1,25(OH)(2)D concentration, we administered bisphosphonate YM529 to OMC-1-bearing rats when they exhibited severe hypercalcemia. The restoration of the serum Ca level by administration of YM529 was accompanied by a marked increase in the 1,25(OH)(2)D level, suggesting that the serum Ca level itself plays an important role in the regulation of the 1,25(OH)(2)D level in these rats. On the other hand, when the OMC-1-bearing rats were treated with a neutralizing antibody against PTHrP, serum 1,25(OH)(2)D levels remained low despite the reduction in serum Ca levels. Expression of 25-hydroxyvitamin D-1 alpha-hydroxylase (1 alpha-hydroxylase) in kidney was decreased in OMC-1-bearing rats with severe hypercalcemia, and markedly enhanced after treatment with bisphosphonate. This enhancement in 1 alpha-hydroxylase expression was not observed after treatment with the antibody against PTHrP. These results suggest that PTHrP was responsible for the enhanced expression of 1 alpha-hydroxylase in YM529-treated rats, and that hypercalcemia played a role in reducing the serum 1,25(OH)(2)D level in OMC-1-bearing rats by suppressing the PTHrP-induced expression of the 1 alpha-hydroxylase gene.

24,25-Dihydroxyvitamin D 3↗
PubMed2001

[Gene abnormality associated with resistance to parathyroid hormone].

Pseudohypoparathyroidism (PHP) is characterized by PTH-resistant hypocalcemia and hyperphosphatemia. Patients with PHP-Ia exhibit Albright osteodystrophy and resistance to TSH and other hormones in addition to PTH. PHP-Ia is caused by heterozygous inactivating mutations in the GNAS1 gene which encodes Gsalpha protein. In PHP-Ib, resistance to PTH is confined to the renal tubules. Recent reports describe a paternally imprinted disorder in a region including the GNAS1 gene as the cause of PHP-Ib.

English Abstract↗
PubMed2001

[Role of advanced glycation endproducts in adynamic bone disease].

To clarify the role of AGEs in adynamic bone disease, we investigated the effect of these substances on cultured human osteoblasts and parathyroid cells. AGEs-BSA significantly inhibited parathyroid hormone secretion in response to the low calcium concentration. In HEK-293 cells, expressing calcium-sensing receptors, the same AGE concentration caused a significant potentiation of the extracellular Ca(2+) induced-intracellular calcium concentration. AGEs significantly inhibited the synthesis of type I collagen and osteocalcin in response to stimulation with 1,25(OH)(2)D(3). These data suggest that AGEs are involved in the pathogenesis of adynamic bone disease by inhibiting PTH secretion in response to hypocalcemia and by inhibiting osteoblastic activity.

English Abstract↗