Search PubMed⌕ Search

Biomedical subjects

S Tajima

Publications and source records attributed to S Tajima.

At least 289 records · Page 16Linked to original sources
PubMed1994

Minimum structural requirements for minoxidil inhibition of lysyl hydroxylase in cultured fibroblasts.

The structural features of minoxidil contributing to its inhibitory effect on lysyl hydroxylase in cultured fibroblasts were investigated. Minoxidil analogs in which the pyrimidine ring (two nitrogens) was replaced with a pyridine ring (one nitrogen) or a sym-triazine ring (three nitrogens) suppressed lysyl hydroxylase activity without affecting prolyl hydroxylase activity, as did an analog in which the piperidine ring was replaced with an N,N-diethyl group. By contrast, minoxidil analogs bearing an N-monoalkyl (ethyl or butyl) group in place of the piperidine substituent failed to suppress lysyl hydroxylase activity. The results indicate that nitroxides of pyridine and triazine, in addition to pyrimidine, having an ortho amino group can act as specific inhibitors of lysyl hydroxylase in the cell. The minimum structural requirement for inhibitory activity appears to be an organic moiety containing a tertiary nitrogen para to the nitroxide oxygen, a condition that is best fulfilled by the piperidine ring in minoxidil. Hydroxylation of minoxidil at the 3 or 4 position of the piperidine ring had no impact on its ability to inhibit the post-translational hydroxylation of lysine during collagen biosynthesis. Fibroblasts treated with minoxidil, 3'-hydroxyminoxidil, or 4'-hydroxyminoxidil synthesized a collagen specifically deficient in hydroxylysine by approximately 70%, which completely accounted for the diminished lysyl hydroxylase activity. The percentage of total proteins synthesized as collagen was reduced minimally by minoxidil but not by 3'- or 4'-hydroxyminoxidil. The studies offer a potential means for therapeutic intervention of excessive collagen deposition during fibrosis, using minoxidil or preferably its hydroxy derivatives to limit the supply of hydroxylysine for collagen crosslink formation.

Cell Line↗
PubMed1994

Mandibular reconstruction using computer-generated three-dimensional solid models.

In mandibular reconstruction, it is necessary to know the exact, three-dimensional extent of the mandible and its defect; the bone graft must be the exact size and dimension of the defect, to assure a precise three-dimensional configuration of the mandible. Previously, the bone graft had to be reshaped during the operation by trial and error, often a time-consuming procedure. The operative procedure has been simulated in advance using three-dimensional, solid models, which has shortened the operating time required.

Bone Transplantation↗
PubMed1994

Application of neutral red staining for evaluation of the viability of dermatophytes and Candida in human skin scales.

The fungal elements observed by direct microscopic examination sometimes fail to grow on subsequent culture. To elucidate the cause of this discrepancy, the viability of dermatophytes and Candida in skin scales was evaluated by neutral red staining. Autoradiographic study using 3H-thymidine confirmed that grain-positive cells (viable cells) were stained with neutral red, whereas negative cells (non-viable cells) were not stained. Taking this as a baseline, the correlation between neutral red-positive fungal elements in scales taken from 211 patients with tinea and 27 patients with cutaneous candidosis and cultures on Sabouraud glucose agar was studied. Strong positive correlations were found in both mycoses. These findings suggest that neutral red staining provides a useful method for evaluating the viability of dermatophytes and Candida in human skin scales.

Arthrodermataceae↗
PubMed1994

Inhibition of elastin synthesis by high potassium salt is mediated by Ca2+ influx in cultured smooth muscle cells in vitro: reciprocal effects of K+ on elastin and collagen synthesis.

Elastin synthesis in cultured smooth muscle cells was inhibited by one fourth in the presence of 0.1 M K+ in the medium. The degree of inhibition paralleled the decrease in the steady-state levels of elastin mRNA. The inhibition of elastin synthesis was blocked by addition of 1 microM nifedipine, a Ca2+ antagonist. Comparable inhibition of elastin synthesis was observed by addition of A23187, a Ca2+ ionophore. In contrast, collagen synthesis and thymidine uptake were stimulated threefold and twofold respectively in the presence of 0.1 M K+ with a concomitant increase in collagen mRNA. The stimulation of collagen synthesis was also blocked by nifedipine. These results indicate that K+ modulates elastin and collagen synthesis and their gene expression reciprocally, and these effects are mediated by Ca2+ influx. Thus K+ exerts profound effects on the composition of extracellular matrices in aorta.

Actins↗
PubMed1994

Coordinate modulation of melanogenesis and type I trimer collagen secretion by type I collagen substratum during reversible conversion between melanotic and amelanotic cells in mouse B16 melanoma.

Two clones, melanotic (M3) and amelanotic (A4) cells, were isolated from B16 mouse melanoma cells. The two clones exhibited distinct phenotypes in cell morphology, melanogenesis, and secretion of extracellular matrix, with preferential secretion of type I trimer collagen in A4 cells. Grown on type I collagen substratum, M3 cells were converted to cells exhibiting similar phenotypes to A4 cells. Subsequent culture of A4-like cells on plastic dishes resulted in the recovery of the initial M3 phenotypes. These results indicate that the reversible conversion between melanotic and amelanotic cells in B16 melanoma cells in vitro is controlled by type I collagen substratum and that modulation of cell shape, melanogenesis, and type I trimer collagen secretion during conversion were all coordinately and reversibly regulated. The results provide evidence that extracellular matrix can control the cell phenotypes in mouse B16 melanoma. Modulation of type I trimer collagen secretion by type I collagen substrate could be a useful model for studying the alpha 1(I) chain-specific regulatory mechanism.

Animals↗
PubMed1994

Tranilast, a selective inhibitor of collagen synthesis in human skin fibroblasts.

Effects of tranilast, N-(3,4-dimethoxycinnamoyl)anthranilic acid, on collagen synthesis in cultured human skin fibroblasts were studied. Tranilast was found to inhibit collagen synthesis in a dose-dependent manner to a maximum of 55% at 300 microM during 48 h of treatment; the synthesis of type I and type III collagens was equally affected. Administered simultaneously or subsequently, tranilast reduced the stimulatory effect of transforming growth factor beta 1 (2.5 ng/ml) on collagen synthesis without affecting the accompanying stimulation of noncollagen protein synthesis. It did not affect prolyl or lysyl hydroxylase activity in vitro and in cells. The content of pro alpha 1(I) collagen mRNA was decreased 60% by tranilast. Tranilast prevented the TGF beta 1-mediated increase in pro alpha 1(I) collagen mRNA. These results indicate that tranilast specifically inhibits collagen production at a pretranslational level by interfering with TGF beta 1 effects. Tranilast also inhibited collagen synthesis in scleroderma fibroblasts to the same extent and in keloid fibroblasts to a greater extent than in normal fibroblasts, attesting to its therapeutic potential as an antifibrotic drug.

Adolescent↗
PubMed1994

Identification of nondisulfided pro alpha 1 (IV) chain produced by cultured B16 melanoma cells.

Two collagenous polypeptides with apparent molecular weights of 180 and 500 kDa under a nonreducing condition were found to be produced in the culture medium of B16 mouse melanoma cells. Under a reducing condition, the higher molecular weight polypeptide (500 kDa) migrated at an identical position to the 180 kDa polypeptide on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both polypeptides were found to have an identical primary structure by V8 protease peptide mapping. Cyanogen bromide cleavage patterns, the fragments produced by pepsin digestion, and partial amino acid sequences of the 180 kDa polypeptide were compatible with those of pro alpha 1 (IV) chain. These results indicate that B16 mouse melanoma cells preferentially produce pro alpha 1 (IV) chains consisting of two forms: disulfide- and nondisulfide-bonded forms.

Amino Acid Sequence↗
PubMed1994

Experimental study of delay of venous island flaps.

If a stable and reliable venous island flap can be elevated, it may enable us to make various flaps everywhere on the body surface by using subcutaneous veins. We have carried out an experimental study to investigate the possibility of increasing the survival area of a venous island flap by a delay procedure. In a proximally based venous island flap, survival area increased when a delay procedure was used, especially with ligation of the distal vein. In a distally based venous island flap, survival area increased when a delay procedure was used without ligation of the proximal vein.

Animals↗
PubMed1994

Expression of type II collagen at the middle stages of chick embryonic and human fetal skin development.

Using in situ hybridization techniques and RNase protection assays, type II collagen mRNA was transiently detected in the epidermis of chick embryonic skins during days 9-15 after fertilization, with a maximum expression at day 11. Immunohistochemical studies demonstrated that deposition of type II collagen was also transiently localized at the subepidermal region during days 10-15. Type II collagen gene and gene product concomitantly started to decline preferentially at the region where feather buds were being formed on day 12, and thereafter diminished at the region between feather buds. Using immunohistochemical methods, type II collagen was also detected in human fetal scalp skin at 17-23 fetal weeks at the subepidermal region, excluding the region beneath the hair follicles. These results indicate that the lack of type II collagen expression is related to the development of feather and hair at a certain stage of chick embryonic and human fetal skin development.

Animals↗
PubMed1994

Biochemical analyses of macromolecular matrix components in patients with pseudoxanthoma elasticum.

Two cases of pseudoxanthoma elasticum (PXE) were reported. Biochemical studies of collagen, glycosaminoglycan, and elastin content were performed using skin specimens from affected lesions. Hydroxyproline content was reduced approximately 46% and 24% in cases 1 and 2, respectively. The reduction in collagen content resulted from the reduction in the lower dermis, not from that in the upper dermis. Glycosaminoglycan content in PXE was also decreased, with a slight increase in the ratio of hyaluronic acid to dermatan sulfate. Isodesmosine content in PXE was increased 3.2- and 2.2-fold in cases 1 and 2, respectively. These results suggest that the major and primary biochemical changes in PXE are an increase in elastin content.

Adult↗
PubMed1994

Production of overmodified type I procollagen in a case of osteogenesis imperfecta.

Collagen synthesis in cultured skin fibroblasts from a patient with osteogenesis imperfecta was studied. Approximately 2 fold accumulation of collagen in the cell layer was found. The slower mobility of pro alpha 1 (I) and pro alpha 2 (I) as well as alpha 1 and alpha 2 (I) polypeptide on sodium dodecylsulfate-polyacrylamide gel electrophoresis was detected, indicating that abnormal posttranslational modification could be present in type I procollagen in patient fibroblasts. The degrees of hydroxylation and subsequent glycosylation of lysine residues in the affected collagen were elevated 1.5 and 1.4 fold, respectively. There were no significant changes in the relative content of type III to type I collagen nor the incorporation of mannose into the carboxyterminal propeptide of pro alpha 1 (I) and pro alpha 2 (I). These results indicate that the patient produces an over-modified type I procollagen which is responsible for the clinical features and has a collagen abnormality already reported in type II osteogenesis imperfecta.

Cells, Cultured↗
PubMed1994

Characterization of the amyloid fibril from primary localized cutaneous nodular amyloidosis associated with Sjögren's syndrome.

BACKGROUND: Primary localized cutaneous nodular amyloidosis (PLCNA) is a rare disease, and its pathogenesis of amyloid deposition is still unknown. OBJECTIVE: The purpose of this study was to know the origin of amyloid in PLCNA. METHODS: Water-soluble amyloid fibrils were isolated from the skin and resolved on SDS-PAGE, then subjected to immunoblot analysis. RESULTS: The major amyloid fibril protein was a 29-kD peptide which reacted with both anti-lambda- and anti-kappa-light-chain antibodies. CONCLUSION: Amyloids in this particular case of PLCNA are derived from the polyclonal immunoglobulin light chain and some cases of PLCNA could be reactive diseases rather than neoplastic ones.

Amyloid↗
PubMed1994

Selective inhibition of a step of myotube formation with wheat germ agglutinin in a murine myoblast cell line, C2C12.

Myoblast cells, C2C12, which is an established cell line from satellite cells of skeletal muscle of C3H mouse, start to fuse and form multinucleated cells (myotubes) and begin to express creatine phosphokinase and myosin, when culture medium is changed from the growth medium to the differentiation medium. Among the 12 lectins that we tested, wheat germ agglutinin apparently suppressed the myotube development judged by phase-contrast microscopy, but did not affect the induction of creatine phosphokinase activity. The addition of N-acetylglucosamine or N,N',N"-triacetylchitotriose, which is a specific ligand for wheat germ agglutinin, to the differentiation medium, recovered this apparently suppressive effect of wheat germ agglutinin on the myotube development. Tachypleus tridentatus (Japanese horseshoe crab) lectin that specifically recognizes N-acetylneuraminic acid, one of the sialic acids, showed no effect on the myotube development. It was suggested that wheat germ agglutinin suppressed the process through recognizing N-acetylglucosamine containing sugar. Surprisingly, even in the presence of wheat germ agglutinin, the ratio of mononucleated cell numbers to the genomic DNA content, which represents the fusion level, decreased after incubation in the differentiation medium, indicating that even when wheat germ agglutinin was present in the medium, cell fusion, which is the initial step of the myotube formation, occurred. Immunostaining with anti-skeletal muscle myosin antiserum confirmed that the myosin expressing cells actually fused and formed multinucleated cells. Their shape, however, was thin compared to that in the absence of wheat germ agglutinin. We propose that the membrane fusion step to form myotubes is composed of two distinct steps in C2C12; one fusion step is to form long and thin myotubes from mononucleated cells and the other one is to develop fat myotubes. Wheat germ agglutinin specifically inhibits the latter fusion step.

Agglutinins↗
PubMed1994

Extradural extension of primitive neuroectodermal tumor--case report.

A 13-year-old boy presented with a primitive neuroectodermal tumor (PNET) with unusual extracranial extension. Precontrast computed tomography showed the tumor as a ring-shaped high-density area which was enhanced postcontrast, with a low-density center. Magnetic resonance imaging showed the tumor as a low-intensity area on the T1-weighted images with marked enhancement by gadolinium-diethylenetriaminepentaacetic acid, and high intensity on the T2-weighted images. The central area appeared as high intensity on both images, suggesting free methemoglobin. The tumor was subtotally removed. Histological examination demonstrated PNET. Despite irradiation (20 Gy) to the surgical site, and further tumor removal, he died 6 months later. This case showed PNET can extend extracranially. Diagnosis and treatment of such a tumor located extracranially and intracranially require careful consideration.

Adolescent↗
PubMed1994

Obstructive sleep apnea attack in complex craniosynostosis.

For treatment of patients with complex craniosynostosis, increased intracranial pressure, severe exophthalmos, and apnea attacks are important indications for operative intervention. Little has been reported on obstructive sleep apnea in complex craniosynostosis. Obstructive sleep apnea attacks in complex craniosynostosis are evaluated in relation to the upper and middle pharyngeal space and to the dimensions of the maxilla and mandible measured on cephalograms. The value of the pharyngeal air space in craniosynostosis had no relationship with either the frequency of sleep apnea attack or with severity of snoring. The dimensions had a close relationship with obstructive sleep apnea attack.

Adolescent↗
PubMed1994

Fully automated flow-injection system for quantifying 1,5-anhydro-D-glucitol in serum.

We have developed a flow-injection system with colorimetric detection to measure 1,5-anhydro-D-glucitol in serum. Serum samples are directly and serially injected into a clean-up column every 3.5 min to remove interferences before the enzymatic reaction. 1,5-Anhydro-D-glucitol, after being passed through the column, is oxidized by immobilized pyranose oxidase (EC 1.1.3.10), and the hydrogen peroxide produced reacts with the chromogen substrate in the presence of immobilized horseradish peroxidase (EC 1.11.1.7) to form Bindshedler's Green. The detection limit was 1.2 mumol/L (1.2 pmol). The correlation between results obtained with the present system (y) and gas chromatography-mass spectrometry (GC-MS) (x) in samples containing < 30 mumol/L 1,5-anhydro-D-glucitol, including many samples from patients with diabetes mellitus, was y = 0.975x-0.111 mumol/L (r = 0.997), which was superior to that obtained between the enzymatic and GC-MS methods. Our system needs only to be set up; it runs without any manual pretreatment, assays 17 samples/h, and shows imprecision (CV) of < 2%.

Autoanalysis↗
PubMed1994

Fully enzymatic method for determining 1,5-anhydro-D-glucitol in serum.

We have developed a fully enzymatic method to measure 1,5 anhydro-D-glucitol (1,5-AG) in serum through use of pyranose oxidase (PROD: EC 1.1.3.10), glucokinase (EC 2.7.1.2), and an ATP-regenerating system. In a previous report (Clin Chem 1989;35:2039-43) the glucose interfering with the measurement of 1,5-AG was removed with a minicolumn. In the method used here, glucokinase and an ATP-regenerating system efficiently convert glucose to the unreactive compound, glucose 6-phosphate, making the method selective for 1,5-AG. The hydrogen peroxide produced in the oxidation of 1,5-AG by PROD is detected with a standard enzymatic color-developing system. The within-run and day-to-day precision (CV) of this method was 0.52-1.29% and 1.17-4.48%, respectively. The correlation (r) between the results obtained with our proposed method (y) and those obtained with the mini-column method (x) was 0.998 (y = 1.007x + 0.493 mg/L; n = 100; Sy/x = 0.641 mg/L). This newly developed method allows quicker and easier measurement of serum 1,5-AG than previously described methods.

Adenosine Triphosphate↗