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Biomedical subjects

A Nakai

Publications and source records attributed to A Nakai.

At least 19 recordsLinked to original sources
PubMed1992

Molecular cloning of a mouse 47-kDa heat-shock protein (HSP47), a collagen-binding stress protein, and its expression during the differentiation of F9 teratocarcinoma cells.

A 47-kDa heat-shock protein (HSP47) is a major collagen-binding stress protein residing in the endoplasmic reticulum, and is assumed to be a molecular chaperone specific to collagen. Two-dimensional gel electrophoresis and immunoprecipitation studies showed that the expression of HSP47 was significantly induced during the differentiation of mouse teratocarcinoma F9 cells by treatment with retinoic acid alone or with retinoic acid and dibutyryladenosine 3',5'-phosphate. The induction of type-IV collagen was also observed during F9-cell differentiation. For further analysis, we cloned cDNA encoding mouse HSP47 from a cDNA library of BALB/c 3T3 cells and performed Northern-blot analysis. The cDNA contained a signal sequence at the N-terminus and an endoplasmic-reticulum-retention signal, RDEL, at the C-terminus. An homology search revealed that mouse HSP47, as well as chick HSP47, belonged to the serine protease inhibitor superfamily. While chick HSP47 mRNA was 4.5 kb with a long (2-kb) 3' untranslated region, mouse and human HSP47 mRNA were 2.5 kb, with a 0.8-kb 3' untranslated region. Northern-blot analysis revealed that the concurrent induction of HSP47 and type-IV collagen during F9-cell differentiation, and the transient induction of HSP47 after heat shock was regulated at the level of mRNA accumulation. These results suggested that HSP47 was closely related to collagens in terms of its expression as well as in its functional relevance.

3T3 Cells↗
PubMed1992

Enantioselective pharmacokinetics of homochlorcyclizine. II: Disposition and metabolism of (+)-, (-)- and racemic homochlorcyclizine after oral administration to man.

The pharmacokinetics of a single oral dose of 20 mg (+)-, (-)- and racemic homochlorcyclizine (HCZ) have been studied in humans. The formation of the quarternary ammonium-linked glucuronide was an important metabolic pathway, and the metabolic process was enantioselective as a result of differing urinary excretion rates of (+)-, (-)- and racemic glucuronide. There were significant differences between (+)-, (-)- and racemic HCZ in AUC (0-14 h) and plasma protein binding, but all HCZ enantiomers were slowly absorbed and eliminated (elimination half-lives about 11 h). The results shows help to establish a more efficient dosage regimen for HCZ therapy.

Administration, Oral↗
PubMed1992

Cushing's syndrome induced by hypersecretion of cortisol from only one of bilateral adrenocortical tumors.

A case of Cushing's syndrome induced by the unilateral (right side) dominance of cortisol secretion in the face of bilateral adrenal tumors is reported. The adrenal tumor resected on the right side was a so-called black adenoma and histologically without any findings of nodular hyperplasia. After resection of the adrenal adenoma, no findings of cortisol hypersecretion from the remaining adrenal tumor on the left side were observed until the present, suggesting that the tumor of the left adrenal gland is a nonfunctioning adenoma. These data imply that the adrenal adenomas have primarily developed from the adrenal gland itself, rather than from micronodular hyperplasia by corticotropin stimulation, and that one of these tumors produces excess hormones initially by corticotropin stimulation, but the other remains in cell proliferation.

Adenoma↗
PubMed1992

Urinary leukotriene E4 after exercise challenge in children with asthma.

To assess the role of sulfidopeptide leukotrienes in the pathogenesis of exercise-induced asthma (EIA), the urinary levels of leukotriene E4 (LTE4), a metabolite of LTC4 and LTD4, were measured by RIA before and after exercise in 13 children with EIA and 10 healthy children. Mass spectrometry was used to confirm the presence of LTE4 in urine and the specificity of the RIA. There was no significant difference in the urinary LTE4 levels before exercise between the children with asthma and healthy children (109 [21 to 265] versus 122 [45 to 156] pg/mg of creatinine; median and range). Urinary LTE4 levels increased significantly after exercise in the children with EIA (from 109 [21 to 265] to 196 [40 to 655] pg/mg of creatinine; median and range; p less than 0.05) but not in the healthy children. The children with asthma demonstrated no significant correlation between the LTE4 level after exercise and the degree of bronchoconstriction, as revealed by the maximal percent fall in the peak expiratory flow rate. Taken together with a recent study that pretreatment with a potent and selective LTD4 antagonist markedly attenuated EIA, our findings suggest that sulfidopeptide leukotrienes may play some role in the pathogenesis of this type of asthma with other factors also being involved in determining the overall airway response.

Asthma, Exercise-Induced↗
PubMed1992

Involvement of the stress protein HSP47 in procollagen processing in the endoplasmic reticulum.

The 47,000-D collagen-binding glycoprotein, heat shock protein 47 (HSP47), is a stress-inducible protein localized in the ER of collagen-secreting cells. The location and collagen-binding activity of this protein led to speculation that HSP47 might participate in collagen processing. Chemical crosslinking studies were used to test this hypothesis both before and after the perturbation of procollagen processing. The association of procollagen with HSP47 was demonstrated using cleavable bifunctional crosslinking reagents. HSP47 and procollagen were shown to be coprecipitated by the treatment of intact cells with anti-HSP47 or with anticollagen antibodies. Furthermore, several proteins residing in the ER were noted to be crosslinked to and coprecipitated with HSP47, suggesting that these ER-resident proteins may form a large complex in the ER. When cells were heat shocked, or when stable triple-helix formation was inhibited by treatment with alpha,alpha'-dipyridyl, coprecipitation of procollagen with HSP47 was increased. This increase was due to the inhibition of procollagen secretion and to the accumulation of procollagen in the ER. Pulse label and chase experiments revealed that coprecipitated procollagen was detectable as long as procollagen was present in the endoplasmic reticulum of alpha,alpha'-dipyridyl-treated cells. Under normal growth conditions, coprecipitated procollagen was observed to decrease after a chase period of 10-15 min, whereas total procollagen decreased only after 20-25 min. In addition, the intracellular association between HSP47 and procollagen was shown to be disrupted by a change in physiological pH, suggesting that the dissociation of procollagen from HSP47 is pH dependent. These findings support a specific role for HSP47 in the intracellular processing of procollagen, and provide evidence of a new category of "molecular chaperones" in terms of its substrate specificity and the dissociation mechanism.

2,2'-Dipyridyl↗
PubMed1992

Quercetin, an inhibitor of heat shock protein synthesis, inhibits the acquisition of thermotolerance in a human colon carcinoma cell line.

Here, we describe the effects of quercetin on the induction of thermotolerance as examined by colony forming assay in a cell line derived from human colon carcinoma (COLO320 DM). Cells became resistant to heat treatment at 45 degrees C when they were preheated at 42 degrees C for 1.5 h or at 45 degrees C for 10 min. This induction of thermotolerance was almost completely inhibited by continuous treatment with 100 microM quercetin during the first and second heating sessions, and the interval between. This effect of quercetin was demonstrated to be dose-dependent over a concentration range of 50-200 microM. Quercetin did not increase the thermosensitivity of non-tolerant cells. The presence of quercetin during the first conditioning heating was more effective in inhibiting thermotolerance than its presence during the second heating. Quercetin was also found to inhibit the acquisition of thermotolerance induced by sodium arsenite. Cycloheximide, a nonspecific inhibitor of protein synthesis, did not affect the acquisition of thermotolerance by the same cell line. Quercetin specifically inhibits the synthesis of all heat shock proteins so far reported previously, and this leads to inhibition of the induction of thermotolerance. Such inhibition of thermotolerance by quercetin may improve the efficacy of clinical fractionated hyperthermia.

Arsenic↗
PubMed1992

Method for optical resolution of racemic homochlorcyclizine and comparison of optical isomers in antihistamine activity and pharmacokinetics.

A method was developed for semi-preparative scale enantioseparation of racemic homochlorcyclizine (HCZ) by high performance liquid chromatography (HPLC) on Chiralcel OD column. The best resolution was achieved using an eluent composed of n-hexane plus 0.2 M isopropylamine. By this method, about 5.0 mg of racemic HCZ could be resolved completely in one run. The optical purity of the enantiomers were both greater than 99.9%. The studies of antihistamine activity on guinea pig ileum demonstrated that l-HCZ is significantly more potent than d- and racemic HCZ. The pharmacokinetics of d- and l-HCZ after oral administration to rats also differed. The successful resolution of racemic HCZ permits comparison of the pharmacokinetics and antihistamine activity of the enantiomers.

Animals↗
PubMed1992

A case of frosted-branch retinal angiitis in a child.

We report the case of a patient with frosted-branch angiitis of the retina in a 3-year-old girl. She had acute visual disturbances OU, and we observed iritis, retinal edema, and retinal angiitis. Retinal angiitis showed the same condition as previously described, the so-called acute frosted retinal periphlebitis accompanied with vascular sheathing. Her eyes improved rapidly after administration of an oral corticosteroid, and during the ensuing four months, she had no recurrences.

Child, Preschool↗
PubMed1991

Identification of the ATP-binding heat-inducible protein of MR = 37,000 as glyceraldehyde-3-phosphate dehydrogenase.

We previously found a novel ATP-binding heat-inducible protein of Mr = 37,000 in BALB/c 3T3 cells. Here, we found that the peptide mapping of this 37-kDa protein was similar to that of rabbit glyceraldehyde-3-phosphate dehydrogenase. Therefore, we biochemically compared the 37-kDa protein with a product translated from mRNA which was hybrid-selected using a cDNA for encoding chick glyceraldehyde-3-phosphate dehydrogenase and found that these two proteins were very similar. Northern blotting analysis using its cDNA as a probe revealed that glyceraldehyde-3-phosphate dehydrogenase was a heat-inducible protein in BALB/c 3T3 cells and that it was induced by stresses including treatment with alpha, alpha'-dipyridyl.

Adenosine Triphosphate↗
PubMed1991

Mucopolysaccharidosis VI (Maroteaux-Lamy syndrome) with hearing impairment and pupillary membrane remnants.

A Japanese boy aged 13 months was referred to us because thickened ribs had been observed on a chest X-ray taken during a respiratory infection. mucopolysaccharidosis type VI (MPS VI) was diagnosed based on urinary glycosaminoglycan analysis and low activity of arylsulfatase B in peripheral leukocytes. He had mild pupillary membrane remnants, but no corneal opacities. The auditory brainstem response revealed moderate hearing impairment, which may have caused his subnormal DQ score of 85 at the age of 19 months. Although MPS VI is characterized by normal intellectual development with normal hearing in early infancy, it is important to examine for hearing loss, especially when an infant with this disease shows developmental delay.

Hearing Disorders↗
PubMed1991

HSP47: a tissue-specific, transformation-sensitive, collagen-binding heat shock protein of chicken embryo fibroblasts.

We report the isolation and characterization of a cDNA clone encoding HSP47, a transformation-sensitive heat shock protein that binds to collagen. A cDNA library was prepared from total RNA isolated from heat-shocked chicken embryo fibroblasts and screened by using oligonucleotide mixtures prepared on the basis of the N-terminal amino acid sequence of biochemically purified HSP47. The cDNA insert contained 3,278 bp, which encoded a 15-amino-acid signal peptide and a mature protein coding region consisting of 390 amino acid residues; it also included part of the 5' noncoding region and a long 3' noncoding region. The deduced amino acid sequence revealed an RDEL sequence at the C terminus, which is a variant of the KDEL retention signal for retention of proteins in the endoplasmic reticulum. Northern (RNA) blot analyses and nuclear run-on assays established that the induction of HSP47 by heat shock and its suppression after transformation of chicken embryo fibroblasts by Rous sarcoma virus are regulated at the transcriptional level. A homology search revealed that this protein belongs to the serpin family, the superfamily of plasma serine protease inhibitors. Although structurally homologous to the serpins, HSP47 lacks the active site thought to be essential for the inhibition of proteases and does not appear to bind to intracellular proteases. HSP47 is the first heat shock protein found to be a member of the serpin superfamily. Conversely, it is the first serpin family member that is not secreted from cells, which could be explained by acquisition of the RDEL retention signal during evolution.

Amino Acid Sequence↗
PubMed1991

Exercise-induced urinary excretion of leukotriene E4 in children with atopic asthma.

Urinary levels of leukotriene (LT) E4, a stable end-product of LTC4 and LTD4, were measured before and after exercise in 10 children with severe asthma and seven children with moderate asthma using HPLC and RIA to clarify the relationship of LT to the severity of asthma and to the degree of bronchospasm in exercise-induced asthma. The urinary LTE4 level significantly increased after exercise in the severe asthma group, but not in the moderate asthma group (14.3 +/- 14.5 to 24.3 +/- 20.6 versus 19.6 +/- 12.3 to 17.6 +/- 10.8 ng/mmol creatinine, p less than 0.05). The urinary LTE4 level increased in 10 patients (eight with severe asthma), and it decreased in seven patients (five with moderate asthma). A significant difference in the degree of bronchospasm after exercise (as shown by the maximal % fall in the peak expiratory flow rate), was seen when patients with increased urinary LTE4 excretion were compared with those with decreased excretion (60.4 +/- 17.3 versus 24.1 +/- 14.3%, p less than 0.01). Our findings suggest that exercise-induced asthma, or at least a subtype of exercise-induced asthma, may partly develop through the release of LTC4.

Asthma, Exercise-Induced↗
PubMed1991

Pathophysiologic study on methylmalonic aciduria: decrease in liver high-energy phosphate after propionate loading in rats.

Methylmalonate or propionate was i.v. infused into B12-deprived and control rats. In the B12-deprived rats, the plasma and liver concentrations of B12 decreased to 8 and 13%, respectively, of those of the control rats. The propionate loading produced a disproportionate increase in liver propionate levels; the mean ratio of methylmalonate to propionate in the liver was approximately 1.0 after methylmalonate loading, whereas it was 0.1 to 0.2 after propionate loading. The liver propionate and methylmalonate levels in the B12-deprived rats were twice as high as those in the control rats. The mean ratio of beta-ATP to inorganic phosphate in the liver, measured with 31P-magnetic resonance spectroscopy, decreased from 0.60 to 0.48 in the B12-deprived rats and from 0.78 to 0.63 in the control rats after methylmalonate loading; the ratio decreased from 0.57 to 0.37 in the B12-deprived rats and from 0.76 to 0.56 in the controls after propionate loading. Statistical analysis showed that propionate loading caused a more marked decrease in ATP than did methylmalonate loading (F = 26.33, degree of freedom 1 and 15; p less than 0.001), while B12-deprivation caused a more marked decrease in ATP than did the control diet (F = 92.26, df 1 and 15; p less than 0.001). The concentrations of tricarboxylic acid cycle intermediates and related organic acids in the livers of the rats suggested that propionate inhibited NAD(+)-dependent enzymes in the cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1990

The roles of three forms of human thyroid hormone receptor in gene regulation.

We have expressed three forms of human thyroid hormone receptor (hTR alpha 1, alpha 2, and beta) in cultured cells by transient transfection. hTR alpha 1 and beta transfected cells showed increased triiodothyronine (T3) binding capacity, but hTR alpha 2 transfected cells did not. When hTR alpha 1 or beta was cotransfected with pUrGH(S), in which a portion of the rat GH 5' flanking region (-236/-147) was ligated into the CAT reporter plasmid (pUTKAT1), T3 increased CAT gene expression. When hTR alpha 2 was cotransfected with pUrGH(S), T3 did not alter CAT gene expression. When hTR alpha 1 or beta was cotransfected with pUrGH(O), in which a synthetic oligonucleotide representing the TRE from the rat GH 5' flanking region (-189/-160) was substituted for the natural enhancer in pUTKAT1, T3 increased CAT gene expression. When hTR alpha 1 and beta were cotransfected with pUrGH(O), induction by T3 was increased. When hTR alpha 2 was cotransfected with hTR alpha 1 or beta, induction by T3 was decreased. These results indicate that hTR alpha 1 and beta function as native TR, that hTR alpha 1 and beta can recognize the same TRE, that hTR alpha 1 and beta can function additively, and that hTR alpha 2 can inhibit the action of hTR alpha 1 and beta.

Animals↗
PubMed1990

Structural analysis of human thyroid hormone receptor beta gene.

Thyroid hormone receptors (TR) are ligand-dependent, DNA-binding, trans-acting transcriptional factors belonging to the erbA-related steroid/thyroid hormone receptor superfamily. To better understand the structural and functional characteristics of TRs, we isolated the gene encoding human TR beta 1 (hTR beta 1). The coding region of hTR beta 1 is split into at least eight exons. Each exon well correlates with functional domains of hTR beta 1 protein, and the exon/intron organization is highly conserved when compared with the chicken c-erbA gene which encodes an alpha-type chicken TR. We demonstrate that hTR beta has at least two mRNA forms having different lengths of the 3' untranslated region. We also note several nucleotide corrections of hTR beta 1 cDNA sequence.

Animals↗
PubMed1990

A novel 40-kDa protein induced by heat shock and other stresses in mammalian and avian cells.

When HeLa cells were exposed to heat shock or other stresses, a 40-kDa protein (p40) was induced in addition to the classical heat shock proteins with molecular sizes of 110-, 90-, 70-, and 47-kDa. The p40 was induced not only by heat shock but by arsenite and 2-azetidine carboxylic acid. Also, it was induced in rat, mouse and chick cells by these stresses. The p40 was a basic protein (pI divided by 9.2) as judged by two-dimensional gel electrophoresis. To our knowledge, p40 is a novel heat shock protein in mammalian and avian cells.

Animals↗
PubMed1990

Transformation of BALB/3T3 cells by simian virus 40 causes a decreased synthesis of a collagen-binding heat-shock protein (hsp47).

The synthesis of a major collagen-binding heat-shock protein of molecular weight 47,000 (hsp47) was shown previously to be decreased after transformation of chick embryo fibroblasts by Rous sarcoma virus (Nagata, K., and Yamada, K. M. (1986) J. Biol. Chem. 261, 7531-7536; and Nagata, K., Saga, S., and Yamada, K. M. (1986) J. Cell Biol. 103, 223-229). In this paper, further study demonstrated that the total amount and the synthesis of hsp47 are also decreased by a factor of three in BALB/3T3 cells transformed by simian virus 40 (SV40). Higher synthesis was observed for BALB/3T3 cells in the resting state compared to those in the proliferating state. The synthesis of hsp47 in SV40-transformed cells, however, was consistently lower than that in normal cells irrespective of the cell density. Pulse label and chase experiments revealed that hsp47 was stable in the cells for at least 6 h and that there was no difference between normal and transformed BALB/3T3 cells in terms of the half-life. Decreases in the amount and the synthesis of hsp47 by transformation apparently correlate with the decreased synthesis of collagen in transformed cells. Immunoprecipitation using rat monoclonal antibody against hsp47 demonstrated the association of hsp47 with intracellular procollagen. Immunofluorescence studies using anti-hsp47 monoclonal antibody and anti-collagen antibody confirmed the co-localization of hsp47 and procollagen in both nonshocked and heat-shocked cells. Furthermore, we determined the biochemical characteristics of hsp47 of heat-shocked cells.

Animals↗