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Biomedical subjects

Y Miyachi

Publications and source records attributed to Y Miyachi.

At least 109 records · Page 6Linked to original sources
PubMed1998

Distinct patterns of collagen gene expression are seen in normal and keloid fibroblasts grown in three-dimensional culture.

The purpose of this study was to examine collagen gene expression in various types of scar fibroblasts as well as normal fibroblasts in a novel three-dimensional culture system and to compare them with those in a monolayer culture system. Cells in three-dimensional culture formed multiple layers within the self-produced dense extracellular matrix and formed a dermis-like structure. In monolayer culture, both normal and scar fibroblasts continued to express high levels of mRNA for pro alpha 1(I) and pro alpha 1(III) collagens. However, in three-dimensional culture, the mRNA levels gradually declined in normal fibroblasts. In contrast, mRNA levels remained high in keloid and hypertrophic scar fibroblasts. Atrophic scar fibroblasts demonstrated similar changes to normal fibroblasts in three-dimensional culture. When we compared mRNA expression in fibroblasts from the centre and the edge of hypertrophic scar, cells from the centre showed a persistently decreased level of collagenase mRNA expression. These results suggest that the mRNA expression pattern of pro alpha 1(I) and pro alpha 1(III) collagens varies depending on the culture system. Fibroblasts from keloids and hypertrophic scar may have a defective system of down-regulation in extracellular matrix metabolism.

Adult↗
PubMed1998

Linear cutaneous lupus erythematosus following the lines of Blaschko.

We describe two Japanese girls with discoid lupus erythematosus (DLE) in whom the condition showed a linear configuration following the lines of Blaschko. The clinical appearance was unusual but histological examination established the diagnosis. After reviewing the previous reports, we found that in six of eight patients with linear 'discoid' lesions, the age at onset was under 14 years; no patient has progressed to systemic lupus erythematosus. Patients with 'linear' DLE may compose a certain clinical subset. We propose the term 'linear cutaneous lupus erythematosus' which may be more suitable for the linear lesions of DLE.

Adolescent↗
PubMed1998

Creeping eruption caused by a larva of the suborder Spirurina type X.

We report a 40-year-old Japanese man with a creeping eruption caused by a larva of the nematode suborder Spirurina type X. He had eaten raw small squid (hotaruika) 4 weeks before the serpiginous erythematous eruption appeared on his abdomen. Routine laboratory tests revealed only slight eosinophilia in his peripheral blood. Although we could not find the larva in an excised skin specimen, an indirect immunofluorescence test confirmed the presence of antibodies against larvae of the suborder Spirurina type X. We review 28 reported cases in Japan which showed that creeping eruption caused by larvae of the suborder Spirurina type X has the following clinical characteristics: an incubation time of 1-4 weeks; a migratory, well-defined, narrow, serpiginous erythematous eruption; and only slight peripheral blood eosinophilia. Excision of the advancing end of the track was curative in our patient.

Adult↗
PubMed1998

Perianal hidradenitis suppurativa: early surgical treatment gives good results in chronic or recurrent cases.

Hidradenitis suppurativa (HS) represents a chronic, recurrent, deep-seated folliculitis resulting in abscesses followed by the formation of sinus tracts and scarring. It is an uncommon disorder frequently involving the perianal region. We review the clinical and pathological features of 12 patients (10 men and two women) with perianal HS (PHS). The mean age at presentation was 43 years (range 24-65), and the mean duration of illness was 14 years (range 2-30). Two patients exhibited multiple areas of involvement, including the axilla and the nape of the neck, in addition to the perianal region. Histological examinations showed epidermis-lined sinuses surrounded by dense plasma cell infiltration in four of nine specimens. The complications related with PHS included anal fistula (seven patients), diabetes mellitus (four), malignant tumour (two) and sepsis (one). Three patients died of the complications. Eight patients underwent wide local excision. The defects were managed with a meshed split-thickness skin graft in five patients, and open treatment in the remainder. New lesions developed in untreated skin of two patients. However, no patient relapsed in the surgically treated sites. PHS is frequently complicated with anal fistula and is occasionally life-threatening as a result of the occurrence of malignant tumours or sepsis. Early surgical excision followed by meshed split-thickness skin graft can successfully cure the lesion without functional disturbance.

Adult↗
PubMed1998

Inhibition of substance P-induced histamine release from rat peritoneal mast cells by low doses of protoporphyrin plus long-wave ultraviolet light irradiation: decreased intracellular calcium as a possible mechanism.

BACKGROUND: A considerable amount of recent interest has been devoted to the down-regulatory effects of photosensitizers plus long-wave ultraviolet light (UVA) irradiation on multiple biologic systems. However, these effects on mast cells are controversial. OBJECTIVE: We have investigated the effect of low doses of protoporphyrin (PP) plus UVA irradiation (PP/UVA) on substance P (SP)-induced histamine release from rat mast cells. METHODS: Rat peritoneal mast cells purified on a Percoll gradient were treated with 3 ng/mL PP and/or UVA, and challenged with SP. In some experiments, IgE-sensitized mast cells were stimulated by antirat IgE in the presence of phosphatidylserine. Histamine released from mast cells and intracellular calcium concentrations ([Ca2+]i) were measured, respectively. RESULTS: SP at a concentration of 10(-5) mol/L caused a significant histamine release with the increase in [Ca2+]i. PP or UVA irradiation alone at doses used in the present study induced no histamine release from mast cells and had no significant effects on SP-induced histamine release from the cells. On the other hand, PP/UVA inhibited SP-induced histamine release in a dose-dependent manner of UVA with the reduction of SP-induced maximal increases in [Ca2+]i. Comparing with the inhibitory effects of PP/UVA on anti-IgE-induced histamine release from IgE-sensitized mast cells and maximal increases in [Ca2+]i in the cells, the inhibitory effects of PP/UVA on the findings in SP-stimulated mast cells were less. CONCLUSION: These data suggest that low doses of PP/UVA inhibits histamine release from SP-activated rat peritoneal mast cells through the suppression of [Ca2+]i.

Analysis of Variance↗
PubMed1998

Phase-contrast microscopic studies using cinematographic techniques and scanning electron microscopy on IgE-mediated degranulation of cultured human mast cells.

BACKGROUND: Isolating human mast cells is a laborious procedure. Recently, cultured human mast cells raised from umbilical cord blood cells have become available. It is necessary to investigate whether IgE-mediated activation of these cells is mediated by exocytosis. OBJECTIVE: To verify IgE-mediated activation of these cultured human mast cells morphologically. METHODS: The mast cells were raised from human umbilical cord blood cells in the presence of stem cell factor and interleukin-6. IgE-sensitized cultured human mast cells were activated by anti-IgE, and morphological changes of the cells were examined under phase-contrast microscopy using cinematographic techniques and scanning electron microscopy. Histamine release from the cells was measured with high-performance liquid chromatography. RESULTS: Under the condition in which a significant histamine release was observed from the mast cells, phase-contrast microscopy showed that the cultured human mast cells became swollen and extruded granules. Scanning electron microscopy disclosed the extrusion of smooth and round bodies from pores formed on the activated mast cell surface. CONCLUSION: IgE-mediated histamine release from cultured human mast cells is accompanied by exocytosis morphologically, indicating that cultured human mast cells will help in studying the functional properties of human mast cells.

Cell Degranulation↗
PubMed1998

Mast cell tryptase stimulates both human dermal fibroblast proliferation and type I collagen production.

BACKGROUND: Mast cell tryptase has been shown to be mitogenic for fibroblasts, however, it still remains unknown whether mast cell tryptase stimulates collagen production by human derrmal fibroblasts. OBJECTIVE: We have investigated the effect of mast cell tryptase on type I collagen production by human dermal fibroblasts as well as the proliferation of the fibroblasts. METHODS: Tryptase isolated from human lung tissue was added to the culture of fibroblasts from normal dermis, and the fibroblast proliferation and the activity of type I collagen synthesis in the supernatants were assayed, respectively. RESULTS: Fibroblast proliferation was increased with tryptase in a concentration-dependent manner, and a significant increase was observed in the presence of tryptase at concentrations from 0.01 to 10 microg/mL. The increase of fibroblast proliferation with 3 microg/mL tryptase was significantly reduced by 15 microg/mL antitryptase IgG antibody, which was demonstrated to inhibit fibrinogenolysis of tryptase. On the other hand, the production of type I collagen by the fibroblasts was significantly increased with tryptase at a concentration of 10 microg/mL. The collagen production in the presence of 10 microg/mL tryptase was significantly inhibited by 50 microg/mL antitryptase IgG antibody. CONCLUSION: Tryptase increases not only the proliferation of human dermal fibroblasts but also type I collagen production.

Cell Division↗
PubMed1998

Human ACTH hypersensitivity syndrome associated with abnormalities of the ACTH receptor gene.

OBJECTIVE: Activating mutations of the ACTH receptor have not been previously described. We investigated a 69-year-old woman with normal blood cortisol but undetectable blood ACTH concentrations. The aim of this study was to evaluate her hypothalamo-pituitary-adrenal axis by measuring circadian variation in blood ACTH and cortisol, and by performing CRH and ACTH stimulation and dexamethasone suppression tests. We also examined biological activity of her circulating blood ACTH using bovine adrenocortical cell suspensions and ACTH receptor gene structure by Northern blotting analysis. RESULTS: Random plasma cortisol concentrations ranged from 182 to 328 nmol/l, while ACTH concentrations were always undetectable. After an intravenous bolus injection of human CRH 100 micrograms, plasma ACTH rose slightly, while plasma cortisol increased appropriately. ACTH stimulation tests revealed that a small amount of ACTH (5 ng/kg b.w.) had the maximal cortisol stimulatory activity, and even smaller amounts of ACTH (0.5 and 0.05 ng/kg b.w.) produced significant increases in cortisol levels. ACTH bioassay of the patient's plasma demonstrated weak biological activity in the HPLC fractions which corresponded to the band of synthetic human ACTH 1-39. The ACTH receptor coding region was amplified by polymerase chain reaction using the leucocyte genomic DNA. There were two base mutations; cysteine 21-->arginine and serine 247-->glycine in the sequences coding for the first extramembranous N-terminal domain and the third extramembranous loop of the ACTH receptor. CONCLUSIONS: This patient with normal blood cortisol but undetectable ACTH levels showed increased adrenocortical sensitivity to ACTH and two point mutations in the ACTH receptor gene. This study, therefore, reports a previously undescribed syndrome--ACTH hypersensitivity syndrome--and provides insights into the molecular mechanism of ACTH receptor action.

Adrenal Cortex Function Tests↗
PubMed1998

Expression of transforming growth factor-beta1 and transforming growth factor-beta Type-II receptor mRNA in papillary thyroid carcinoma.

Transforming growth factor-beta1 (TGF-beta1) is a potent inhibitor of epithelial cell proliferation. Signal transduction by TGF-beta1 involves direct binding to the TGF-beta Type-II receptor and then the formation of a heterodimeric complex of TGF-beta Type-I and Type-II receptor. To explore the role of TGF-beta1 in thyroid carcinoma, we examined the expression of TGF-beta1 and TGF-beta Type-II receptor mRNA by northern blotting analysis in both 14 papillary thyroid carcinomas and surrounding normal thyroid tissues. Relative mRNA level was determined by scanning densitometry of the autoradiogram and corrected for loading differences using a human beta-actin cDNA probe. The relative mRNA levels of TGF-beta1 in 12 out of 14 papillary thyroid carcinomas were higher than those in surrounding normal thyroid tissues. In contrast, the relative mRNA levels of TGF-beta Type-II receptor were reduced to 60.1+/-18.3% of those of normal thyroid tissues in 10 papillary thyroid carcinomas. There were no clear relationships between the relative mRNA levels for TGF-beta1 and TGF-beta Type-II receptor and the histological characteristics of papillary thyroid carcinomas. The relative mRNA levels for TGF-beta1 and TGF-beta Type-II receptor did not show significant differences in thyroid carcinomas with or without lymph node metastases. There was a negative correlation between the TGF-beta Type-II receptor mRNA level and tumor size, while no significant correlation was observed between the TGF-beta1 mRNA level and tumor size. In conclusion, most papillary thyroid carcinomas overexpress TGF-beta1 mRNA but exhibit a reduction in TGF-beta Type-II receptor mRNA. The reduction of TGF-beta Type-II receptor mRNA may play a role in the pathogenesis of papillary thyroid carcinoma.

Adult↗
PubMed1998

Carnoy's fixative reduces the number of chymase-positive cells in immunocytochemical staining of cord-blood-derived human cultured mast cells.

KleinJan et al. (Allergy 1996;51:614-20) reported that Carnoy's fixative reduced the number of chymase-positive mast cells in the nasal mucosa. Therefore, in the present study, we investigated whether Carnoy's fixative reduces the number of chymase-positive cells from cord-blood-derived human cultured mast cells when compared with other types of fixatives. Human mast cells were obtained by culturing cord-blood-derived CD34-positive cells in the presence of stem cell factor and interleukin-6. Staining procedures of the cells in fixation with Carnoy's fixative and with other fixatives gave no differences among the number of tryptase-positive cells, whereas fixation with Carnoy's fixative for 15 min gave a significant decrease in the number of chymase-positive cells compared with acetone for 10 min. The number of chymase-positive cells decreased in a time-dependent manner under fixation with Carnoy's fixative, indicating that Carnoy's fixative had a negative effect on the number of chymase-positive cells from cord-blood-derived human cultured mast cells.

Acetic Acid↗
PubMed1998

Mast cells in clinical dermatology.

Recent advances in cutaneous mast cell biology are briefly reviewed with special reference to our own studies on cultured human mast cells. Of note are the heterogeneity of mastocytosis, the important participation of mast cells in allergic inflammation by releasing cytokines and the inhibitory effect of histamine release from mast cells by phototherapy. It is also stressed that mast cells play a major role in tissue remodelling. These novel findings suggest that mast cells can no longer be regarded simply as cells that initiate immediate allergic reactions, but that they are responsible for various chronic inflammatory or immunological events through cytokine-dependent leucocyte recruitment. The regulation of mast cell activation should be a critical issue and, thus, a promising therapeutic approach in clinical dermatology.

Humans↗
PubMed1998

Dermal connective tissue metabolism in photoageing.

The term photoageing describes the clinical and histological cutaneous changes that are the consequence of repeated chronic sun exposures and are qualitatively different from those observed in chronological ageing. The connective tissue of the skin is composed mainly of collagen, glycosaminoglycans and elastin and, thus, alterations of these components in photoageing are briefly reviewed in the present article. Collagen changes in photoageing are partly explained by cross-links as well as the unbalanced regulation of collagen production and breakdown. Some visible skin changes can be induced by the consequence of dermal glycosaminoglycans, because the total amount, as well as the composition of the main disaccharide units, is significantly altered in the exposed sites of both aged people and photoaged mice. As for the mechanism of solar elastosis, increased elastin mRNA levels resulting from transcriptional up-regulation of the gene have been reported. Taken together, all components of the dermal connective tissue are affected by chronic actinic damage; however, further in vitro investigation is required to unmask the exact events in photoageing. With regard to this, our novel three-dimensional culture system should be of great help because it mimics the in vivo condition by self producing the extracellular matrices.

Collagen↗
PubMed1998

Immunological features of patients with primary biliary cirrhosis (PBC) overlapping systemic sclerosis: a comparison with patients with PBC alone.

To characterize the immunological features of patients with primary biliary cirrhosis (PBC) overlapping systemic sclerosis (SSc), 26 patients with PBC were classified according to the presence of scleroderma-related features (Raynaud's phenomenon, sclerodactyly etc.). The patients were classified into 10 patients with PBC overlapping SSc (PBC-SSc), four patients with some scleroderma-related features although not meeting the criteria of SSc (PBC-SSc spectrum) and 12 patients with PBC alone. Sera from PBC-SSc showed a significantly higher positivity to anti-centromere antibody (P< 0.01) and to E1beta of pyruvate dehydrogenase complex (P< 0.005) than those from patients with PBC alone. The same tendency was observed in PBC-SSc spectrum patients. Patients with PBC exhibiting scleroderma-related features, in both the PBC-SSc and PBC-SSc spectrum, may comprise a subset in PBC, not only clinically, but also immunologically.

Adult↗
PubMed1998

Inhibition of substance-P-induced histamine release from rat peritoneal mast cells by 8-methoxypsoralen plus long-wave ultraviolet light irradiation: decreased intracellular calcium as a possible mechanism.

Rat peritoneal mast cells purified on a Percoll gradient were activated by substance P (SP) and the effect of 8-methoxypsoralen (8-MOP) plus long-wave ultraviolet light (UVA) irradiation (8-MOP/UVA) on SP-induced histamine release from the cells was investigated. At a concentration of 10(-5) M SP caused a significant histamine release. 8-MOP or UVA irradiation alone at the doses used in the present study neither induced a histamine release nor had any significant effects on SP-induced histamine release from mast cells. On the other hand, 8-MOP/UVA inhibited SP-induced histamine release; this inhibition was dependent on the UVA doses (0.5-3.0 J/cm2) and was accompanied by a reduction in the rise in intracellular calcium concentrations ([Ca2+]i). These data suggest that 8-MOP/UVA inhibits histamine release from SP-activated rat peritoneal mast cells by suppressing the rise in [Ca2+]i.

Animals↗
PubMed1998

Interferon-alpha-induced thyroid dysfunction in patients with chronic active hepatitis C: a transient, reversible and self-limited dysfunction.

To survey the prognoses of interferon-alpha (IFNalpha)-induced thyroid dysfunction, a total of 100 patients (49 males and 51 females) with biopsy-proven chronic active hepatitis C were studied. Either during or after IFNalpha therapy, 29 patients (33.7%) revealed suppression/elevation of thyroid stimulating hormone (TSH) or both, transient thyrotoxicosis (TSH less than 0.1 microU/ml) or transient hypothyroidism (TSH 5.0-190.95 microU/ml). However, the thyroid function normalized without supplementation of the thyroid hormone in the follow-up period. In the same period, one of the 14 control patients (7.1%) developed thyroid dysfunction. Thyroid abnormalities developed significantly more in patients with IFNalpha therapy than in those without IFNalpha therapy. The findings suggest that the occult autoimmune disorder becomes overt with IFNalpha treatment in patients with pre-existent autoimmune thyroid disease. IFNalpha-induced thyroid dysfunction is transient, reversible and self-limited. It is not necessary to discontinue IFNalpha therapy when thyroid dysfunction develops.

Adult↗
PubMed1998

Photosensitive drug eruption induced by flutamide.

We describe a 68-year-old man who showed a photosensitive drug eruption induced by flutamide. The minimal erythema dose with ultraviolet A light was reduced to 2 J/cm2 under administration of flutamide, which recovered to over 16 J/cm2 after cessation of the medication, without changing the reactivity to ultraviolet B. The absorption spectrum of flutamide was not altered after ultraviolet A irradiation, suggesting that flutamide is photostable with regard to ultraviolet A. In addition, bovine serum albumin was not covalently photocoupled with flutamide under ultraviolet A. Thus, flutamide seems to have low potency to act as a photohapten, and it is likely that a non-photohaptenic mechanism operates in this photosensitivity or its active metabolite may work as a photosensitizer.

Aged↗