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Biomedical subjects

I Miyamoto

Publications and source records attributed to I Miyamoto.

At least 37 records · Page 2Linked to original sources
PubMed1991

Identification and characterization of xpac protein, the gene product of the human XPAC (xeroderma pigmentosum group A complementing) gene.

We have cloned human xeroderma pigmentosum group A complementing (XPAC) cDNA that encodes a "zinc finger" protein with a predicted size of 31 kDa. To detect the xpac protein in cells, we raised antibody against a recombinant human xpac protein. Using this antibody, we identified the xpac protein in the nucleus of cells. In normal human cells, 40- and 38-kDa proteins were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A reduced amount of the smaller protein was detected in XP 39OSSV cells, which show low UV sensitivity, and no xpac proteins were detected in XP 2OSSV cells, which show high UV sensitivity. These levels of xpac proteins in xeroderma pigmentosum cells were determinants of heterogeneity of the DNA repair defect in group A xeroderma pigmentosum. Synthesis of the xpac protein did not increase after UV irradiation.

Blotting, Western↗
PubMed1991

[The frequency and mechanisms of urolithiasis in acromegaly].

It is generally accepted that acromegaly is often associated with hypercalciuria, but there are few reports on the frequency and the mechanisms of urolithiasis. Recently we consecutively experienced 2 cases of acromegaly with urolithiasis, and these experiences made us investigate the association between urolithiasis and acromegaly. Among 18 acromegalies from 1977 to March 1990 (10 males, 8 females, 24-64 years old), 13 cases (72%) fulfilled the criteria of hypercalciuria (urinary calcium (u-Ca) greater than or equal to 200 mg/day or u-Ca/urinary creatinine (u-Ca/u-Cr) greater than or equal to 0.15), and 7 cases (39%) suffered from urolithiasis that was diagnosed by KUB (4 cases) or X-ray computed tomography (CT) (3 cases). Especially in the last 2 years, 5 out of 7 cases (71%) were complicated with urolithiasis and all 7 cases were associated with hypercalciuria. These results suggest that hypercalciuria and urolithiasis are both much more frequent than previously reported. In 6 cases who were treated by pituitary adenomectomy from 1988-1989 (4 males, 2 females, 24-59 years old), we examined Ca metabolism before and after operation. Before operation, the levels of serum growth hormone (GH), u-Ca (mg/day), u-Ca/u-Cr (in all cases) and plasma somatomedin-C (Sm-C) (in 4 cases) were increased above the normal range. To determine the etiology of hypercalciuria, we performed the oral Ca load test under restriction of Ca (400 mg/day) and P (650 mg/day) intake. The results suggested that the hypercalciuria might be mainly due to the increased absorption of Ca from the intestine (so-called "Absorptive hypercalciuria"). However, the levels of serum vitamin D (Vit. D) metabolites were all within the normal range before operation. After operation, GH and u-Ca/u-Cr (in 5 cases) and u-Ca (mg/day) (in all cases) decreased significantly compared with before operation, and the levels of Sm-C (in all cases), serum 25-(OH)D3, 1 alpha, 25-(OH)2D3 (in 4 cases) and 24,25-(OH)2D3 (in 3 cases) were also reduced after operation. Surprisingly, u-Ca and u-Ca/u-Cr normalized only in 4 cases who showed a reduction in 1 alpha, 25-(OH)2D3 levels after operation, although there were no correlations between u-Ca (mg/day) or u-Ca/u-Cr and 1 alpha, 25-(OH)2D3. Significant correlations were found between u-Ca (mg/day) or u-Ca/u-Cr and Sm-C. The parathyroid function evaluated by the rapid Ca infusion test or nephrogenous cyclic adenosine monophosphate (NcAMP) was normal before and after operation.(ABSTRACT TRUNCATED AT 400 WORDS)

Acromegaly↗
PubMed1991

Cyclosporine A (CyA)-induced decrease of serum gonadotropin levels in a case of Klinefelter's syndrome.

We report a case of Klinefelter's syndrome who developed a decrease of serum gonadotropin levels, particularly LH, after CyA treatment for complicated focal glomerulosclerosis (FGS). A 38-year-old man suffering from general malaise and pretibial edema was diagnosed FGS by renal biopsy in October 1988, and was referred to our hospital for further evaluation and treatment for FGS in December 1988. He was not married, and closer anamnesis revealed that he had had impaired seminal ejaculation from the age of 30. The physical examination showed 37% obesity, scanty body hair, pretibial edema and small bilateral testes (3.0 x 1.5cm). Laboratory findings included marked proteinuria (5.3g/day) and mild renal dysfunction (serum creatinine 1.3mg/dl, glomerular filtration rate 57.2ml/min). Endocrinologically, high basal levels of LH and FSH (133.6mIU/ml and 93.7mIU/ml, respectively) and the hyperresponses of LH and FSH to LH-RH stimulation were found, but the other pituitary hormone levels, thyroid and adrenal status, were in the normal range. In testicular biopsy, nodularly proliferated Leydig cells and no seminal tubules could be seen. The chromosome analysis showed 47,XXY karyotype, which confirmed the diagnosis of Klinefelter's syndrome in this patient. From 9 January 1989, CyA (6mg/Kg.day) was orally administered for 4 weeks in order to treat for FGS. After CyA administration, basal levels of LH and FSH remarkably decreased, particularly LH, and their decrease lasted for at least 6 weeks after cessation of CyA (final levels; LH 28.2mIU/ml, FSH 69.8mIU/ml). On the other hand, serum testosterone level was low normal or slightly under normal, and no apparent changes could be seen during CyA treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Measurement of human hair growth by optical microscopy and image analysis.

We have developed a quantitative method for measuring hair growth using optical microscopy and image analysis, and have used this to investigate the rate of growth in subjects with and without alopecia. The hairs were cut from an area 7-8 mm in diameter and 24 h and 72 h later, images of the areas were obtained using an optical microscope and were recorded on a video disc. Measurements of the regrowing hairs, placed parallel to the scalp using a glass slide attached to the front of the microscope, were made using the image analyser. In subjects with little or no baldness there was a clear difference between fast-growing hairs and resting or slow-growing hairs. However, in subjects with alopecia there was no such difference and the growth rate of all the hairs showed a continuous distribution. Using this method other parameters such as the number of hairs per unit area and hair diameter as well as grouping of the hairs could be measured.

Adult↗
PubMed1990

Analysis of a human DNA excision repair gene involved in group A xeroderma pigmentosum and containing a zinc-finger domain.

Xeroderma pigmentosum (XP) is an autosomal recessive disease, characterized by a high incidence of sunlight-induced skin cancer. Cells from people with this condition are hypersensitive to ultraviolet because of a defect in DNA repair. There are nine genetic complementation groups of XP, groups A-H and a variant. We have cloned the mouse DNA repair gene that complements the defect of group A, the XPAC gene. Here we report molecular cloning of human and mouse XPAC complementary DNAs. Expression of XPAC cDNA confers ultraviolet-resistance on several group A cell lines, but not on lines of other XP groups. Almost all group A lines tested showed abnormality or absence of XPAC messenger RNAs. These results indicate that a defective XPAC gene causes group A XP. The human and mouse XPAC genes are located on chromosome 9q34.1 and chromosome 4C2, respectively. Human XPAC cDNA encodes a protein of 273 amino acids with a zinc-finger motif.

Amino Acid Sequence↗
PubMed1990

Characterization of a splicing mutation in group A xeroderma pigmentosum.

The molecular basis of group A xeroderma pigmentosum (XP) was investigated by comparison of the nucleotide sequences of multiple clones of the XP group A complementing gene (XPAC) from a patient with group A XP with that of a normal gene. The clones showed a G----C substitution at the 3' splice acceptor site of intron 3, which altered the obligatory AG acceptor dinucleotide to AC. Nucleotide sequencing of cDNAs amplified by the polymerase chain reaction revealed that this single base substitution abolishes the canonical 3' splice site, thus creating two abnormally spliced mRNA forms. The larger form is identical with normal mRNA except for a dinucleotide deletion at the 5' end of exon 4. This deletion results in a frameshift with premature translation termination in exon 4. The smaller form has a deletion of the entire exon 3 and the dinucleotide at the 5' end of exon 4. The result of a transfection study provided additional evidence that this single base substitution is the disease-causing mutation. This single base substitution creates a new cleavage site for the restriction nuclease AlwNI. Analysis of AlwNI restriction fragment length polymorphism showed a high frequency of this mutation in Japanese patients with group A XP: 16 of 21 unrelated Japanese patients were homozygous and 4 were heterozygous for this mutation. However, 11 Caucasians and 2 Blacks with group A XP did not have this mutant allele. The polymorphic AlwNI restriction fragments are concluded to be useful for diagnosis of group A XP in Japanese subjects, including prenatal cases and carriers.

Amino Acid Sequence↗
PubMed1990

Chloranil-photosensitized monomerization of dimethylthymine cyclobutane dimers and effect of magnesium perchlorate.

The photosensitized monomerization of the cyclobutane dimers of 1,3-dimethylthymine by p-chloranil was investigated by means of steady-state irradiation and laser-flash photolysis. Quantum yields for the monomerization are 0.34 for the cis,syn dimer, 0.39 for the trans,syn dimer, and much less than 10(-2) for the cis,anti isomer. Formation of the chloranil anion radical associated with quenching of triplet chloranil by the dimers demonstrates that electron transfer from dimers to triplet chloranil occurs to initiate the monomerization. Kinetic analysis suggested that the syn-dimer cation radicals undergo the ring cleavage at greater than or equal to 10(9) s-1 before escaping from the solvent cage, while the reactivity of the anti-dimer cation radical is very low. The different reactivities of the syn and anti dimer cation radicals are discussed in terms of through-bond coupling between the n orbitals of N(1) and N(1') involving the cyclobutane-ring sigma orbitals. In the cases of the syn-dimers, the sensitizer-dimer ion-radical pairs undergo the rapid geminate recombination that works as a major energy dissipating channel responsible for the lower-than-unity quantum yields. It has been found that the presence of Mg(ClO4)2 at 0.1 M enhances approximately 1.5 times either the monomerization of the syn dimers or the formation of the chloranil anion radical. A laser-flash photolysis study shows that Mg2+ forms a complex with either the triplet or the anion radical of chloranil. The net salt effects are attributed to the retardation of the rapid geminate recombination by the participation of Mg2+ in the sensitizer-dimer ion-radical pairs.

Chloranil↗
PubMed1990

[Polysaccharides in fungi. XXV. Biological activities of two galactomannans from the insect-body portion of Chán hua (fungus: Cordyceps cicadae)].

Biological activities of two galactomannans (CI-P and CI-A) isolated from the insectbody portion of Chán hua (fungus: Cordyceps cicadae) were studied. CI-P having low affinity for concanavalin A (Con A) exhibited potent carbon-clearance activity in mouse, although both polysaccharides had little antitumor activity against sarcoma 180 in mice. Furthermore, CI-P and CI-A was found to have potent hypoglycemic activity in normal mice, and CI-A having high affinity for Con A showed slightly higher activity than CI-P.

Animals↗
PubMed1990

[Immunohistochemical studies of the acne-like inflammatory model].

The acne-like inflammatory model was produced in the ears of male Sprague-Dawley rats by subcutaneous injection of 140 micrograms of heat killed Propionibacterium acnes (P. acnes). Ear thickness was measured as an index of inflammatory strength, using a micro indicator once every day for the first week, then every other day until the 35th day. Animals were sacrificed and ears were excised for histological study. The tissue was stained with Hematoxylin and Eosin to investigate the state of inflammation. At the same time, P. acnes was stained specifically by enzyme labelled antibody to study the localization of the injected bacteria body. When thickness of rat ears was measured, more than a doubling of control ear was observed with maximum swelling on the second day. The ear thickness decreased to 1.5 times control levels at 5th day, then remained with no change for 35 days. Histological study revealed remarkable inflammatory infiltration of lymphocytes and neutrophils at the swelling site. Polynucleocyte was major infiltrated cells until 24 hours, and then mononucleocyte was principal after 24 hours. In the tissue excised at 6 hours after injection, a temporary characteristic infiltration of eosinophils was observed. When the tissue at 35th day was stained by enzyme labelled antibody, it revealed that the antigen of P. acnes existed among the cells at the site of infiltration and in mononucleocytes. This inflammatory model is considered to be a valuable experimental animal model for acne vulagaris with granulomatous inflammation.

Acne Vulgaris↗
PubMed1989

Comparison of the regional distribution of calspectin (nonerythroid spectrin or fodrin), alpha-actinin, vinculin nonerythroid protein 4.1, and calpactin in normal and avian sarcoma virus- or Rous sarcoma virus-induced transformed cells.

With fluorescence and interference reflection microscopy (IRM), we compared the regional distribution of calspectin, its interacting proteins (nonerythroid protein 4.1 and calpactin), alpha-actinin, and vinculin in NRK cells and their avian sarcoma virus (ASV)- or temperature-sensitive (ts) Rous sarcoma virus (RSV)-transformed cells. The localization of these cytoskeletal proteins was determined with the specific antibodies. In NRK cells, alpha-actinin and vinculin were concentrated at adhesion plaques. By contrast, calspectin was distributed throughout the cytoplasm, but not concentrated at adhesion plaques. In ASV- and ts RSV-transformed cells, all three cytoskeletal proteins were concentrated at dot structures representing cellular feet. Nonerythroid protein 4.1 and calpactin were diffusely distributed throughout the cytoplasm of NRK cells and their transformed counterparts. In the case of calpactin, a part of this protein was excluded near regions of the terminal ends of stress fibers. These two proteins did not show the restricted location at the dot structures of transformed cells. From these findings, it is apparent that the accumulation of calspectin into dot structures is a specific event for cell transformation induced by the src protein.

Actinin↗
PubMed1988

Succinic acidemia: a new syndrome of organic acidemia associated with congenital lactic acidosis and decreased NADH-cytochrome c reductase activity.

Two siblings with succinic acidemia, a hitherto unreported organic acidemia, were investigated. Succinic acidemia, lactic acidosis and respiratory distress were observed in one of the siblings, who died 37 days after birth, and succinic acidemia was also detected in the next sibling at the fetal stage. NADH-cytochrome c reductase activity was significantly low in both cases and NADH-ferricyanide reductase activity was also low in the fetal case, suggesting a complex I deficiency of the electron transport system in the mitochondrial membrane.

Acidosis, Lactic↗
PubMed1988

Effects of active oxygen scavengers on the peroxidation of linoleic acid catalyzed by dehydro-L-ascorbic acid or its degradation products.

The addition of 1,4-diazabicyclo-[2,2,2]octane (DABCO) (100 mM) or 1,2-dihydroxybenzene-3,5-disulfonic acid (Tiron) (1 mM) to a reaction mixture containing 10 mM linoleic acid (LA), 20% EtOH, and 135 microM dehydroascorbic acid (DHA) as a catalyst suppressed LA peroxidation, but the addition of mannitol (approximately 100 mM), uric acid (100 microM), and catalase (6.5 units) did not. DHA or 2,3-diketo-L-gulonic acid (DKG) accelerated LA peroxidation, but the splitting products of DHA did not affect LA peroxidation. These results suggest that some specific radicals are liberated in the degradation of DHA or DKG.

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium ↗
PubMed1988

[A case of transitional cell carcinoma of the bladder with heterotopic bone formation].

A 85-year-old woman consulted our clinic due to asymptomatic macrohematuria on January 6, 1987. In the cystoscopic examination, solitary and pedunculated bladder tumor was revealed. This tumor was located on the retrotrigonal region near the right ureteral orifice. On January 20, transurethral resection of bladder tumor was planned but the base of the tumor was stony hard, so complete resection was not performed. On February 10, transurethral resection of bladder was performed repeatedly. At that time, the cystoscopic finding showed that the tumor size had increased and transurethral bladder ultrasonography showed invasion into the deep muscular layer. On February 17, total cystectomy and ileal conduit was done. Histological examination revealed poorly differentiated TCC with osteoid, bone and cartilage. This patient was discharged in good condition on March 27. Heterotopic bone formation in the bladder tumor is rare. Ten cases were collected from the literature. We report a case of heterotopic bone formation and discuss the mechanism of the etiology.

Aged↗
PubMed1987

Unsaturated fatty acids in mammalian cell strains cultured for more than 10 years in serum-free synthetic media.

In cultured cells, essential lipids are usually supplied by the serum added to the culture medium. However, in a serum-free medium, essential lipids would need to be synthesized by the cells. Cell strains derived from kidney, spleen, uterine carcinoma and fibroblasts were cultured in serum-free synthetic media for more than 10 years and their fatty acids were analyzed capillary column gas-liquid-chromatography. The following conclusions were drawn: 1. Polyunsaturated fatty acids were not detected. Thus, prostaglandins are not appear to be essential for initiation of DNA synthesis in these cells. 2. A compensatory increase of the content of monounsaturated fatty acids was detected. 3. A large difference in vaccenic/oleic acid ratio was found among several strains of cells, but the ratio does not reflect that of the original tissues.

Animals↗
PubMed1984

Purification and characterization of hyaluronic acid from the horny layer of guinea pigs.

Hyaluronic acid was purified from the horny layer of guinea pigs and its biochemical and physical properties were studied. The horny layer, obtained by applying n-hexadecane to guinea pig skin, was digested with pronase, and glycosaminoglycans in the digest were separated from UV-absorbing material by Sephadex G-75 chromatography (sample A, 17.5 mg). On DEAE-Sephadex chromatography, the fraction obtained with 0.5 M NaCl was found to contain 94% of the total uronic acid. This fraction, consisting mainly of hyaluronic acid, was dialyzed and lyophilized (sample B, 12.5 mg). Sample B, consisting of 26.1% uronic acid and 27.0% glucosamine on a dry weight basis, could be digested completely with Streptomyces hyaluronidase. Sample B had a low reduced viscosity which showed almost no concentration dependence. The intrinsic viscosity of sample B was 0.83 dl/g and its molecular weight, calculated from its viscosity, was 34,000. Sample B was eluted from Sepharose CL-6B as a broad peak between the void volume and the total column volume. The enzyme levels of hyaluronidase, beta-glucuronidase, and beta-N-acetylglucosaminidase in the n-hexadecane treated guinea pig skin increased to 1.7 to 2.5 fold those of controls after 6 days of the experiment. These results suggested that hyaluronic acid in the horny layer of n-hexadecane treated guinea pig skin might be degraded by hyaluronic acid degrading enzymes in the hyperkeratinized tissue.

Animals↗
PubMed1984

Age-related changes in the molecular weight of hyaluronic acid from rat skin.

Age-related changes in the molecular weight of hyaluronic acid from the skin of rats was studied using fetuses, newborn animals and rats 1, 2, 3, 4, 13, 26 and 52 weeks of age. Average values of the molecular weight of hyaluronic acid varied with age in three phases: 39 X 10(4) in fetuses and up to the age of one week, 55 X 10(4) in individuals aged to 26 weeks and 87 X 10(4) in individuals 52 weeks of age. The distribution of molecular weight was quite different between 4 weeks and 52 weeks of age. At 4 weeks of age, the molecular weight of hyaluronic acid was widely distributed, ranging from 18 X 10(4) to 79 X 10(4), while that from 52-week-old individuals was very high with a distribution ranging from 92 X 10(4) to 119 X 10(4).

Aging↗
PubMed1982

A simple method for the determination of glucosamine and galactosamine using cellulose acetate electrophoresis.

A new electrophoretic method is presented for the determination of glucosamine and galactosamine. The technique is quite simple and rapid, it involves cellulose acetate electrophoresis in borate buffer (200 V, 15 min) and silver nitrate staining. Hexosamine samples of 0.36-1.80 micrograms were separated and stained within 30 min. This method was applied for the hexosamine analysis of glycosaminoglycans.

Animals↗