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Biomedical subjects

A Miyauchi

Publications and source records attributed to A Miyauchi.

At least 145 records · Page 8Linked to original sources
PubMed1990

A new analysis method for cataractous images taken by retroillumination photography.

Photographic data have been used to diagnose cataracts. In particular, retroillumination photographs are popular and useful owing to their clearness of whole images of crystalline lenses at a glance. A new procedure called grid method for the quantitative analysis of retroillumination photographs is proposed here. With this method a ratio of cataractous area to total area can be calculated by separating an image of a lens in grids, with a greater precision compared with the usual threshold method. Furthermore, based on a correlation check of the grid number and the resulting accuracy we determined that 25 grids is the optimal cutting for our grid method.

Cataract↗
PubMed1990

Differential effects of a single dose of cyclophosphamide on T cell subsets of the thymus and spleen in mice: flow cytofluorometry analysis.

Sequential changes in the distribution of lymphocyte subpopulations of the thymus and spleen in BALB/c mice (male, 8-weeks old) during 2 weeks after a single i.p. injection of cyclophosphamide (CY, 200 mg/kg body weight) were studied mainly through the use of CD4, CD8 and CD3-epsilon markers together with single- or two-color flow cytofluorometry. In the thymus on Day 2 after CY treatment, a marked decrease in the number and proportion of PNAhi, CD3- and CD4+CD8+ double positive (DP) subpopulation was observed in parallel with a marked reduction in the thymus weight, cortical area and total thymocyte number. This phenomenon might be associated with the decrease in the percentage of thymocytes at the S phase of the cell cycle on Day 1 and 2 after CY treatment, owing to the depletion of the rapidly dividing cells in DP subset. There was a significant reduction in the number and proportion in CD4+ single positive(SP) subset on Day 7. The cell number of CD8+SP subset continued to decrease during Day 7 to Day 14. This contrasted with the behaviors of DP, CD4+SP and CD4-CD8- double negative (DN) subsets in which a considerable recovery was attained by Day 14. The spleen from CY-treated mice showed a marked decrease in the DN subset and surface immunoglobulin-positive cells, perhaps B lymphocytes, in both the percentage and the absolute cell number on Days 2 and 7, which paralleled the marked reduction in its weight and total cell number. The absolute cell numbers of CD4+SP and CD8+SP subsets in the spleen were also reduced on Days 2 and 7. The reduction of the CD4+SP/CD8+SP ratio was found in the thymocytes on Days 2 and 7 but not in spleen cells. Our results suggest that the principal target cell population of CY is the PNAhi, CD3- and DP immature cortical thymocytes as well as splenic B cells. The sustained decrease in the number of CD8+SP thymocytes after CY treatment might be in part relevant to the potentiating effect of CY pretreatment on immune responses.

Animals↗
PubMed1990

[Three cases of occult thyroid cancer with mediastinal lymph node metastasis manifesting as a mediastinal cyst].

We experienced three cases (one 38-year-old male, 58-year-old and 67-year-old females) whose resected mediastinal cysts proved to be metastatic lymph nodes from occult thyroid cancer. Primary lesions in thyroid gland were detected by echography in all three cases though they were detected in one case out of two by CT, in one out of three by 201T1 scintigraphy, in two out of three by 123I scintigraphy. After these examinations on thyroid gland, operations (one lobectomy, one hemithyroidectomy, one total thyroidectomy) were performed. Primary lesions in thyroid gland were all papillary carcinomas, and ranged 4 x 3 mm to 12 x 10 mm in size. Multiple foci were found in two cases, many intrathyroidal metastases in one case, cervical lymph node metastases in two cases. In cases of mediastinal cyst, thyroid gland should be examined by echography paying attention to the mediastinal lymph node metastasis from occult thyroid cancer. When occult thyroid cancer with mediastinal lymph node metastasis is diagnosed, total thyroidectomy followed by 131I radiation therapy is recommended as the treatment for a primary lesion, because of multiple foci in thyroid gland and intrathyroidal metastases.

Adult↗
PubMed1989

Close linkage of MEN2A with RBP3 locus in Japanese kindreds.

The gene responsible for multiple endocrine neoplasia type 2A (MEN2A) has recently been assigned to the pericentromeric region of chromosome 10 in European Caucasian kindreds by linkage analysis using a DNA marker, interstitial retinol-binding protein 3 (RBP3). We have found tight linkage between the MEN2A and RBP3 loci in Japanese MEN2A kindreds. The maximum lod score is 5.19 at a recombination fraction of 0.00. This result suggests that mutation of a certain gene close to RBP3 is responsible for MEN2A irrespective of ethnic backgrounds.

Female↗
PubMed1989

Effects of human PTH-related peptide and human PTH on cyclic AMP production and cytosolic free calcium in an osteoblastic cell clone.

Recently, human parathyroid hormone-related peptide (hPTHrP) has been purified and its amino acid sequence determined. Within the amino-terminal 13 residues of hPTHrP, 8 amino acids were found homologous between hPTHrP and human PTH (hPTH). This peptide was reported to stimulate cyclic AMP (cAMP) production in osteoblastic cell lines (UMR106 and ROS17/2.8). However, whether or not this peptide affects another second messenger, i.e., cytosolic free calcium ([Ca2+]i), in osteoblasts has not yet been determined. Therefore, in the present study, we examined the effects of synthetic amino-terminal fragments of hPTHrP (Tyr40hPTHrP1-40 and hPTHrP1-34) on intracellular cAMP production and [Ca2+]i in an osteoblastic cell line (MC3T3-E1) and compared them with those of hPTH1-34. Human PTHrP1-34, Tyr40hPTHrP1-40 and hPTH1-34 stimulated cAMP production in an equipotent manner at concentrations ranging from 2.5 x 10(-10) to 1.3 x 10(-6) M. Human PTH1-34 at concentrations from 2.5 x 10(-7) to 1.3 x 10(-6) M significantly (P less than 0.05) increased [Ca2+]i, but hPTHrP1-34 and Tyr40hPTHrP1-40 at the same concentrations did not. These results suggest a different receptor-mediated mechanism for [Ca2+]i increase between hPTHrP and hPTH, although these two peptides appear to share the same receptor site(s) which is coupled to the cAMP system in MC3T3-E1.

Animals↗
PubMed1989

Radioimmunoassay of circulating alpha-interferon with reference to aging and osteoporosis.

Circulating immunoreactive alpha-interferon in elderly individuals was 0.139 +/- 0.042 ng/ml in males and 0.111 +/- 0.033 ng/ml in females at ages 70-79, and 0.120 +/- 0.045 ng/ml in males and 0.105 +/- 0.039 ng/ml in females at ages 80-89. These values were significantly lower than those in young adults (p less than 0.01), but higher compared with the values found in disease states including rheumatoid arthritis (p less than 0.0025). There was no correlation between circulating alpha-interferon and bone mass indices, such as bone mineral content or quantitative computed tomography values, in these elderly individuals. Circulating alpha-interferon was, however, significantly increased in senile osteoporotic patients after 2 months of treatment with 1 alpha-hydroxyvitamin D3 or calcitonin, whereas it was unaltered in patients receiving ipriflavone or in nonosteoporotic individuals without medication. These findings indicate that circulating alpha-interferon, which is highest in young adults, declines with aging. It appears that circulating alpha-interferon is maintained at a certain steady-state level in healthy elderly individuals. Although there was no apparent relationship between bone mass indices and circulating alpha-interferon, it is possible that bone and cellular metabolism related to vitamin D3 may be contributing factors for the maintenance of circulating alpha-interferon.

Aged↗
PubMed1989

[Roles of epidermal growth factor (EGF) in the growth and differentiation of human endometrium].

Endometrial tissues undergo drastic changes during menstrual cycle. After menstruation, they proliferate and differentiate into cells with secretory activity in the preparation for egg implantation. Although sex steroids play an important role in the development of endometrial tissues, sequential events occurring in the endometrium can not be fully explained by the direct actions of sex steroids. In this study, we offer evidences that EGF is released from endometrial cells and they possess the receptor for EGF. These findings prompted us to explore the biological roles of EGF in endometrial tissues. Here we clearly demonstrate that EGF is involved in the proliferation of endometrial cells. Moreover, EGF is found to enhance both glycogenesis and glycogenolysis, thus increasing the supply of glucose for blastocysts. We further set forth that EGF augments the capacity of progestin receptor and release of prostaglandins in endometrial cells. In summary, this study emphasizes that EGF may participate in the development of human endometrial tissues in concert with sex steroids, thus contributing to the acquisition of receptivity of eggs in the endometrium.

Cell Differentiation↗
PubMed1989

Voltage dependent calcium channel expression in isolated osteoclasts.

In this study the expression of voltage-dependent calcium channels on osteoclast plasma membrane has been investigated. We found that osteoclasts were sensitive to KCl-induced depolarization. In this circumstance a 4 fold transient cytosolic calcium concentration ([Ca2+]i) increase was observed. This increase was dose-dependent. Its half maximal effect was achieved at 30 mM KCl. Voltage sensitive calcium channels in osteoclasts were inhibited by specific antagonists. Nicardipine, a dihydropyridine derivative, was the most effective, inducing complete block of the channels at 10(-6) M. Verapamil (phenylalkylamine) and diltiazem (benzodiazepine) were less effective. These results are consistent with the presence, on the osteoclast membrane, of L-type voltage-sensitive calcium channels.

Animals↗
PubMed1989

Allele loss on chromosome 10 and point mutation of ras oncogenes are infrequent in tumors of MEN 2A.

The multiple endocrine neoplasia type 2A (MEN 2A) gene has been mapped to the centromeric region of chromosome 10 by linkage analysis. We examined 36 medullary thyroid carcinomas (MTCs) (16 hereditary and 20 sporadic) and ten pheochromocytomas (eight hereditary and two sporadic) to detect loss of alleles on chromosome 10 using seven polymorphic DNA markers mapped to this chromosome. Of 20 informative cases, only one (5%) sporadic MTC showed loss of heterozygosity at the locus RBP3. Allele loss at the RBP3 locus was not found in pheochromocytomas from six heterozygotes. All tumors retained constitutional heterozygosity at six other loci on chromosome 10 (D10S17, D10S34, D10S24 on the short arm, D10S15 in the pericentromeric region, D10S20, and D10S4 on the long arm). Our findings suggest that the second hit for tumorigenesis in MEN 2A may not be loss of function of the normal allele at the homologous locus on the other copy of chromosome 10. Mutated ras oncogene was found only in one of 18 MTCs at the codon 61 of H-ras.

Adrenal Gland Neoplasms↗
PubMed1989

[A case of cardiac myxoma associated with long-term lasting symptoms of mitral stenosis].

We reported a case of 70-year-old woman whose left atrial myxoma was resected. She had been suffered from low cardiac output due to mitral stenosis for 15 years or more. Resection of the myxoma corrected mitral stenosis completely. Cardiac output and pulmonary wedge pressure, however, were not improved following the operation. Postoperative echo- and angiocardiography revealed marked early closure of the mitral valve. These findings indicate that left ventricular compliance should be reduced if inflow stenosis continued for a long period and it is difficult to improve depressed ventricular function even if mitral stenosis is completely removed.

Aged↗
PubMed1988

Parathyroid hormone control of free cytosolic Ca2+ in the kidney.

We have established a perifusion system to monitor free cytosolic calcium concentrations ([Ca2+]i) in mouse kidney slices, which presumably reflects in vivo status more accurately than renal cells in culture, by means of the fluorescent calcium indicators quin-2 and fura-2. An increase in the extracellular calcium concentrations from 0 (no added Ca2+) to 3.0 mM resulted in an increase in [Ca2+]i from 52 to 239 nM. Replacement of 118 mM of extracellular Na+ with choline, or the addition of ouabain, an inhibitor of Na+,K+-ATPase, at 10(-6) M in the perfusate caused an increase in [Ca2+]i from 161 +/- 13 to 873 +/- 78 nM (n = 10) and 161 +/- 13 to 395 +/- 68 nM (n = 4), respectively, suggesting the possible existence of a Na+,Ca2+ exchange mechanism in the kidney slice. We further examined the effects of PTH on [Ca2+]i mobilization in the kidney. Both human PTH-(1-34) and hPTH-(1-84) increased [Ca2+]i within 60 s at physiologic concentrations of 10(-11)-10(-9) M in a dose-dependent manner. On the other hand, an increase in intracellular cAMP in the slice was also detected above 3 X 10(-9) M hPTH-(1-34) [base 2.1 +/- 0.4 pmol/mg, 3.2 +/- 0.6 pmol/mg (p less than 0.05 versus control values) 5 minutes after the application of 3 X 10(-9) M hPTH-(1-34) and 17.3 +/- 4.3 pmol/mg (p less than 0.05 versus control values) 3 X 10(-8) M hPTH-(1-34), mean +/- SEM, n = 7, p less than 0.05 versus control values].(ABSTRACT TRUNCATED AT 250 WORDS)

Aminoquinolines↗
PubMed1988

Hemangiopericytoma-induced osteomalacia: tumor transplantation in nude mice causes hypophosphatemia and tumor extracts inhibit renal 25-hydroxyvitamin D 1-hydroxylase activity.

Although more than 50 patients with the tumor-induced osteomalacia syndrome, characterized by remission of unexplained osteomalacia after resection of a coexisting tumor, have been reported, the pathogenesis of this syndrome is still not clear. We investigated the cause of biopsy-confirmed osteomalacia which was resistant to treatment with 1 alpha-hydroxyvitamin D3 in a 54-yr-old man. He had severe hypophosphatemia, a high serum alkaline phosphatase level, a low plasma 1,25-dihydroxyvitamin D level, and remarkably increased urinary phosphorus excretion. A tumor, with histological characteristics of a hemangiopericytoma, was found on his left thigh. After surgical removal of this tumor, his plasma 1,25-dihydroxyvitamin D and serum phosphorus levels increased to normal levels, and his bone pain subsided. The tumor was transplanted to athymic nude mice. A nodule formed in each mouse, with histological features identical to those of the original tumor, and the tumor-bearing mice had hypophosphatemia, high serum alkaline phosphatase levels, and increased urinary phosphorus excretion. When extracts of the original tumor were added to primary cultures of renal tubular cells, renal cAMP levels did not change, but 25-hydroxyvitamin D-1 alpha-hydroxylase activity was significantly inhibited. These data indicate tumoral production of some humoral factor(s) inhibiting 25-hydroxyvitamin D-1 alpha-hydroxylase activity and phosphorus reabsorption unrelated to adenylate cyclase-cAMP production in proximal renal tubules.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1988

[Evaluation of surgical results and prediction of prognosis by analysis of serum tumor marker levels: proposal of a theory tested on patients with medullary thyroid carcinoma].

A theory to evaluate the benefit of surgery and to predict the prognosis in patients with a malignant tumor by analysis of serum tumor marker levels is proposed, and an analysis of 67 patients with a medullary thyroid carcinoma is reported as an example of its application. This theory incorporates the following concepts: the tumor marker doubling time, the reduction index, the expected prolongation of survival by surgical therapy, and the expected duration of survival after surgery. These parameters allow a quantitative judgement of the surgical therapy and a quantitative prediction of the subsequent prognosis as demonstrated in patients with a medullary thyroid carcinoma.

Adult↗
PubMed1987

Ultrastructural study of poorly differentiated medullary carcinoma of the thyroid.

Five cases of sporadic medullary carcinoma of the thyroid (MTC) with rapidly progressive disease were studied ultrastructurally. The tumour cells had poorly differentiated C cell characteristics. They exhibited smaller secretory granules in their narrow cytoplasm. Morphometric analysis disclosed that the average diameter of the secretory granules of the cases with a poor prognosis was 173.0 nm in comparison with 254.2 nm of well differentiated cases. The granules were fewer in the poor prognostic group (1.31/mu 2) than the well differentiated group (2.75/mu 2). Increased free ribosomes and polysomes were noted in the cytoplasm and dispersed chromatin in the nuclei. These cases should be therefore classified as poorly differentiated MTC rather than atypical or anaplastic MTC.

Adult↗