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H Yabuuchi

Publications and source records attributed to H Yabuuchi.

At least 73 records · Page 4Linked to original sources
PubMed1988

[The effect of purification procedures on the determination of serum level of 1,25-dihydroxyvitamin D].

The advance in knowledge of clinical disorders involving calcium and bone diseases has resulted in part from the development of assay procedures for the major vitamin D metabolites, but the values of the same samples measured in different laboratories vary considerably. They suggest that the chromatographic purification involved in these assays seems to be a critical step. In this study, we compared the results of 1,25-dihydroxyvitamin D (1,25(OH)2D) using different chromatographic purification methods: Sephadex LH-20 column chromatographic purification (non-HPLC method) described by Mallon et al. and High Performance Liquid Chromatographic purification (HPLC method) modified by Yamaoka et al. Serum 1,25(OH)2D levels of healthy volunteers before and after oral load of 4 micrograms of 1 alpha-hydroxyvitamin D3 (1 alpha OHD3) were measured by the two different methods mentioned above. A good correlation (r = 0.951, p less than 0.001) was noted in the samples before loading. The mean values of serum 1,25(OH)2D before loading did not differ significantly between HPLC method and non-HPLC method. After loading, however, the mean value of serum 1,25(OH)2D was significantly higher in non-HPLC method (p less than 0.01). The values of 1,25(OH)2D were determined in the serum added 1,25-dihydroxy-24-oxo-vitamin D3 (24-oxo-D3) (0 pg/ml, 200 pg/ml or 2000 pg/ml). In the samples added 2000 pg/ml of 24-oxo-D3, the mean value of 1,25(OH)2D was significantly higher in non-HPLC method (p less than 0.001). The affinity of 24-oxo-D3 for 1,25(OH)2D3 cytosolic receptor was evaluated in chick embryo intestinal mucosa and rachitic chick intestinal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Multiple associated endocrine abnormalities in a patient with pseudohypoparathyroidism type 1a.

A girl with type 1a pseudohypoparathyroidism (PHP) presented several hormonal abnormalities. Although she had eluded neonatal thyroid screening, she was diagnosed as having hypothyroidism at the age of 5 months. Thereafter, a diagnosis of PHP was made on the basis of skeletal features of Albright osteodystrophy and lack of both cyclic adenosine monophosphate (c-AMP) and phosphaturic responses after parathyroid hormone (PTH) infusion. The basal levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were higher than normal and showed exaggerated responses to luteinizing hormone-releasing hormone (LH-RH). There was no growth hormone (GH) response to arginine infusion, and the prolactin (PRL) response after thyrotropin-releasing hormone (TRH) infusion, was also impaired. The stimulating guanine nucleotide-binding protein (Ns) activity of the erythrocytes was reduced to 66.9%. The skeletal age was not delayed at the age of 5 months in spite of the hypothyroid state, and it advanced following thyroxine and vitamin D treatments.

Age Determination by Skeleton↗
PubMed1988

Microcarriers facilitate mineralization in MC3T3-E1 cells.

MC3T3-E1 cells showed mineral deposits after about 1 week of culture when incubated in the presence of microcarrier beads. These deposits appeared as white spots on the dish surface, and under light microscopy the cells showed multiple cell layers and mineralization around the microcarriers. The deposits stained positive with calcium-specific Von Kossa's method. Using conventional assay, alkaline phosphatase activity (ALP) and parathyroid hormone-stimulated intracellular cAMP production were lower in the microcarrier cultures than in the control, but using cytochemical methods, high alkaline phosphatase activity was found around the microcarriers. These results indicate that microcarriers facilitated the formation of multiple cell layers and provided a culture environment for mineralization.

Alkaline Phosphatase↗
PubMed1988

Chiari I malformation with quadriplegia and respiratory disturbance in an infant.

Chiari I malformation consists of variable downward displacement of the cerebellar tonsils. Quadriplegia, respiratory disturbance and pain are common in Chiari I malformation in adults. However, there are no reports of this syndrome in early childhood. We report the case of a 9-month-old girl with Chiari I malformation who had quadriplegia with muscle weakness and who developed respiratory disturbance as an early symptom. The causes of the symptoms of Chiari I malformation are discussed. The use of MRI is proposed as a more useful diagnostic technique than myelography for these patients since MRI is less likely to aggravate the respiratory disturbance.

Age Factors↗
PubMed1988

Renal 25-hydroxyvitamin D3-1-hydroxylase in patients with renal disease.

Renal 25-hydroxyvitamin D3-1-hydroxylase (1-hydroxylase) activity has been measured in 20 patients with renal disease using the remaining portion of needle renal biopsy specimens taken for diagnostic purposes and in five patients using kidney tissue removed during transplantation. The 1-hydroxylase activity of 12 patients with asymptomatic proteinuria and/or hematuria (group A) measured 83.2 +/- 37.7 pg/mg tissue/20 min. Since these 12 patients did not show impaired mineral metabolism or pathological changes in the renal tubules, we have presumed that these results indicate normal activity in man. We also measured the 1-hydroxylase activity in four patients treated with prednisolone (group B). The 1-hydroxylase activity (81.1 +/- 27.1 pg/mg tissue/20 min) of group B did not differ from that of group A. However, the urinary excretion of calcium (ratio of calcium/creatinine) was increased (0.18 +/- 0.07 vs. 0.07 +/- 0.03, P less than 0.01) by prednisolone therapy. These data suggest that glucocorticoid-induced changes in urinary calcium excretion are not the result of a direct effect of glucocorticoid on renal 1-hydroxylase. In the three patients with mild renal insufficiency (group C), the 1-hydroxylase activity (75.4 +/- 22.4 pg/mg tissue/20 min) did not differ from that of group A. However, in five patients with severe renal insufficiency (group D), the 1-hydroxylase activity (8.5 +/- 3.7 pg/mg tissue/20 min) was significantly decreased (P less than 0.01).

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1988

T-cell receptor beta-chain gene expression in B-lineage acute lymphoblastic leukemia.

The T-cell receptor beta-chain (T beta) gene expression was examined in 16 children with B-lineage acute lymphoblastic leukemia (ALL), including eight patients with rearrangement of the T beta gene as well as immunoglobulin (Ig) heavy chain gene rearrangement. In contrast to the 1.3 kb full-length transcripts of the T beta observed in T-lineage leukemia and lymphoma cells, no transcript of the T beta gene was detected in 10 patients, including four with T beta gene rearrangement. Low levels of T beta transcripts were found in three patients with T beta gene rearrangement and two patients without T beta gene rearrangement, but those transcripts were truncated. In contrast to those findings, a single patient with T beta gene rearrangement showed abundant 1.3 kb T beta transcripts. These data indicate that T beta gene expression is not restricted to T-lineage cells and demonstrate the heterogeneity of B-lineage ALL at the expression level of the T beta gene. Our findings also suggest that T beta gene expression is not always accompanied with T beta gene rearrangement.

B-Lymphocytes↗
PubMed1988

A family with pseudodeficiency of acid alpha-glucosidase.

A unique family is presented which consists of a patient with the juvenile muscular dystrophy form of glycogenosis type II and four healthy individuals, both parents and sisters, with low acid alpha-glucosidase activity. It was almost impossible to distinguish the homozygote from the heterozygous members by lymphocyte assay alone. In cultured skin fibroblasts, acid alpha-glucosidase activity measured with a synthetic substrate was less than 1% of the normal mean value in the patient and about 15% in the parents. The activity toward glycogen was not detectable in the patient and was about 30% of the normal mean value in the parents. These values are also lower than expected in heterozygotes. To explain these results properly, a new mutant allele of acid alpha-glucosidase is proposed. Both parents could be compound heterozygotes for the pseudodeficiency allele and the juvenile form of glycogenosis type II allele.

Adolescent↗
PubMed1988

Delayed bone development in epileptic children assessed by microdensitometer.

Bone development of metacarpal bones was assessed by microdensitometer analysis of hand X-rays from 101 epileptic outpatients. Most of the patients were treated with two or three anticonvulsant drugs; however, 27 patients were treated with only one. A significantly larger number of patients showed a delay in bone development of 2 or more years when compared with either handicapped or normal control children. In epileptic children, physical activity and the duration of anticonvulsant therapy were correlated with bone development. Patients with delayed bone development had reduced levels of serum 25-OH-D (p less than 0.005) and elevated levels of 1,25-(OH)2D (p less than 0.01). Microdensitometer analysis of metacarpal bone radiographs is useful for detecting mild impairment of bone in groups of epileptic children.

Adolescent↗
PubMed1988

Quantitative cineangiographic analysis of ventricular volume and mass in patients with single ventricle: relation to ventricular morphologies.

With the use of biplane selective ventriculography, the ventricular volume, ejection fraction, and ventricular mass were evaluated in 28 patients with a single ventricle, and those with the left ventricular type (LV type, 12 patients) and right ventricular type (RV type, 16 patients) were compared. There were no significant differences in terms of age, hemoglobin, systemic oxygen saturation, or pulmonary-to-systemic flow ratio in the two groups. No patients with atrioventricular valve regurgitation were included. The ventricular cavity volume was calculated by the area-length method. The ventricular mass volume was determined as the shell volume created by subtracting the ventricular cavity volume from the total ventricular volume calculated by adding the free wall thickness to the chamber dimensions. The ventricular mass volume was converted to mass by multiplying by the gravity of the heart muscle. There was no significant difference between patients with the LV type and RV type of single ventricle with respect to the end-diastolic ventricular volume (188 +/- 53 and 179 +/- 61 ml/m2 in LV and RV types, respectively), end-systolic volume (88 +/- 31 and 84 +/- 27 ml/m2), or ejection fraction (0.54 +/- 0.06 and 0.52 +/- 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Volume↗
PubMed1988

Metabolism of cerebroside sulfate and subcellular distribution of its metabolites in cultured skin fibroblasts from controls, metachromatic leukodystrophy, and globoid cell leukodystrophy.

With pulse-chase study of 1-[14C]stearic acid-labeled cerebroside sulfate (14C-CS) and subsequent subcellular fractionation by Percoll gradient, the metabolism of CS and translocation of its metabolites in human skin fibroblasts from controls, metachromatic leukodystrophy (MLD), and globoid cell leukodystrophy (GLD) were studied. In control skin fibroblasts, CS was transported to lysosome and metabolized there to galactosylceramide (GalCer) and ceramide (Cer) within 1 h. During the chase period, radioactivity was increased at plasma membrane plus Golgi as phospholipids and no accumulation of GalCer or Cer was found in lysosome. In MLD fibroblasts, 95% of 14C-CS taken up was unhydrolyzed at 24 h-chase and accumulated at not only lysosome but also plasma membrane. In GLD fibroblasts, GalCer was accumulated throughout the subcellular fractions and more accumulated mainly at plasma membrane plus Golgi with longer pulse. This translocation of lipid from lysosome seems to have considerable function, even in lipidosis, which may result in an imbalance of the sphingolipid pattern on the cell surface and these changes might be one of causes of neuronal dysfunction in sphingolipidosis.

Cell Compartmentation↗
PubMed1988

Effects of the administration of phosphate on nuclear 1,25-dihydroxyvitamin D3 uptake by duodenal mucosal cells of Hyp mice.

Effects of the administration of phosphate on nuclear 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] uptake by duodenal mucosal cells of Hyp mice were investigated. In Hyp mice fed a high phosphate diet (1.1% Ca and 2.0% phosphate) for 2 weeks, maximal nuclear 1,25-(OH)2D3 binding by duodenal mucosal cells is significantly increased from 5.01 +/- 0.49 x 10(3) to 8.23 +/- 1.10 x 10(3) sites/cell (P less than 0.05). No significant change was observed in normal mice fed the same diet. The serum phosphate concentration of Hyp mice increased significantly (P less than 0.01), whereas no significant change was found in normal mice. On this regimen, serum calcium, urinary cAMP to creatinine ratio, and cytosolic 1,25-(OH)2D3 receptor number in Hyp mice were not changed significantly. On the basis of these data, we speculate that the recovery of serum phosphate in Hyp mice fed a high phosphate diet affects the recovery of nuclear 1,25-(OH)2D3 uptake by duodenal mucosal cells. The mechanism for this recovery is not related to either the secondary hyperparathyroidism or the change in cytosolic 1,25-(OH)2D3 receptor content but, rather, to increased binding of 1,25-(OH)2D3-receptor complex to nuclei. Hypophosphatemia, therefore, appears to play a role in the vitamin D resistance in Hyp mice.

Animals↗
PubMed1988

Biochemical studies on lymphoblastoid cells with inherited N-acetyl-glucosamine 1-phosphotransferase deficiency (I-cell disease).

Lymphoblastoid cells transformed by Epstein-Barr virus from peripheral lymphocytes of normal individuals and I-cell disease (ICD) patients were used for the enzymic study of lysosomal hydrolases and N-acetylglucosamine 1-phosphotransferase. ICD lymphoblastoid cells secreted a larger amount of hydrolases into medium than normal cells, although the intracellular hydrolases were not deficient in ICD cells. The stimulating effect of 10 mM ammonium chloride on secretion of hydrolases was found only with normal cells, and not with ICD cells, indicating that the hydrolase molecule bearing mannose 6-phosphate was secreted. The ICD lymphoblastoid cells retained the enzymologic characteristics of both lysosomal hydrolases and N-acetylglucosamine 1-phosphotransferase seen in ICD fibroblasts, which allows us to study the pathophysiology of ICD in cells other than fibroblasts.

Adsorption↗
PubMed1988

[Diagnosis of cancer at the DNA level].

Recent recombinant DNA techniques have made possible the production of gene probes and the search for genetic damage in neoplastic cells, and now occupy one of the central place in cancer research. More recently, detection of immunoglobulin and T cell receptor gene rearrangements has been shown to be a powerful procedure for identifying monoclonality and the cellular lineage of lymphoid cells even when conventional studies give an ambiguous diagnosis. Such genetic markers are not only useful for differential diagnosis and classification, but serves also as a sensitive unique clonal marker to detect early cancer relapse. In a similar manner, chromosomal translocations associated with specific disease types can be detected with DNA probes in southern blot analysis without the use of conventional cytogenetics. These methods have wider application and will play an increasing role in the clinical use in the near future.

Carcinogens↗
PubMed1988

Effect of phosphorus supplementation on bone formation induced by osteosarcoma-derived bone-inducing substance in X-linked hypophosphatemic mice.

In our previous report, we demonstrated normal cartilage and bone matrix formation and a defect of bone mineralization in hypophosphatemic (Hyp) mice using an ectopic bone formation system. That system consisted of an osteogenic sarcoma-derived bone-inducing substance. In this report, we describe the effect of phosphorus supplementation on abnormal bone mineralization. The osteogenic sarcoma-derived bone-inducing substance was implanted in Hyp mice or control mice. The Hyp mice were divided into two groups after implantation. One group was fed a normal laboratory chow, while the other was fed a high-phosphorus diet for 4 weeks of the experimental period. Normal control mice were fed the normal laboratory chow. The mean serum phosphorus level in the high-phosphorus diet group was normal at 2, 3 and 4 weeks after implantation. Using the method of 85Sr incorporation, the high-phosphorus diet group showed marked improvement in bone mineralization at 2 and 4 weeks after implantation, but incomplete improvement at 3 weeks. On the other hand, histological study of the high-phosphorus diet group at 4 weeks after implantation still showed a meaningful amount of the osteoid matrix formation compared to the control. These findings suggest that the abnormal bone mineralization in Hyp mice was mainly due to their abnormally low serum phosphorus level. However, still other abnormalities might exist and these might be responsible for the incomplete improvement in bone mineralization.

Animals↗