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Biomedical subjects

Y Sasai

Publications and source records attributed to Y Sasai.

At least 55 records · Page 3Linked to original sources
PubMed1996

Microfluorometric study of nuclear DNA in normal human epidermis.

Quantitative and qualitative changes of nuclear DNA were analyzed by microfluorometry in normal human epidermis during terminal differentiation. Normal human epidermis from five healthy volunteers was separated by an EDTA-trypsin method and fractionated by Percoll density gradient. Staining was carried out with either Feulgen reaction, Acridine Orange or 4'-6-diamidino-2-phenylindole (DAPI). When the cells with lower density (granular layer cells) were stained with Acridine Orange or DAPI, the greatest population was found at lower value of DNA than that in the cells stained with Feulgen reaction. After thermal denaturation procedure, a ratio of double-stranded DNA to single-stranded DNA was highest in the cells with lower density. These results seem to suggest the qualitative and quantitative changes of nuclear DNA during terminal differentiation of human epidermal keratinocytes.

Acridine Orange↗
PubMed1996

Effects of transforming growth factor beta 1 in the hair cycle.

Hair follicle growth is thought to be regulated by a complex interplay of stimulatory and inhibitory signals. From among such signals, we examined the effects of transforming growth factor beta 1 (TGF beta 1) on the murine hair growth cycle. Quantitation of TGF beta 1 per wet tissue weight was performed at different stages of the hair cycle. TGF beta 1 was extracted with 10 mM HCl, and its level was measured with ELISA. The level of TGF beta 1 did not change markedly during the hair cycle. Immunohistochemical observations revealed that hair follicle cells and epidermal cells were negative for TGF beta 1 at all stages of the hair cycle. Mast cells in the dermis were positive throughout the cycle. To confirm whether the proliferation of hair follicles. Our observations suggest that TGF beta 1 is at least partly responsible for regulating hair follicles as a negative growth factor.

Animals↗
PubMed1996

Serum levels of eosinophil cationic protein reflect the state of in vitro degranulation of blood hypodense eosinophils in atopic dermatitis.

In patients with atopic dermatitis (AD), serum levels of eosinophil cationic protein (ECP) have been shown to be a good reflector of disease severity. To elucidate what serum levels of ECP actually reflect, ECP levels in serum and plasma and cytological aspects of blood eosinophils were examined in AD patients (n = 27) and compared to healthy subjects (n = 12). Significantly elevated levels of serum ECP were noted in AD patients, while plasma ECP were uniformly recorded at nadir levels in both AD patients and normal subjects. In addition to blood eosinophilia, AD patients had significantly increased numbers of hypodense eosinophils (HEo) with morphological characteristics consistent with an activated state. Serum ECP levels strongly correlated with HEo numbers rather than with total eosinophil counts. These results indicate that elevated levels of serum ECP may be a consequence of in vitro degranulation of "activated" HEo, not of ECP supplementation from lesional skin. In addition, the dynamic correlations of eosinophil-associated parameters (total eosinophil counts, HEo numbers, and serum ECP levels) with AD severity suggest that inflammatory events in lesional skin may be involved in causing not only eosinophilopoiesis in bone marrow, but also development of HEo in the periphery, whose degree in turn may be mirrored in the levels of serum ECP in vitro.

Adult↗
PubMed1996

Secondary amyloidosis complicating arthropathic psoriasis.

We report a patient with secondary systemic amyloidosis complicating arthropathic psoriasis. At autopsy amyloidosis was observed in the spleen, kidneys, liver, gastro-intestinal tract, lung, heart, pancreas, adrenal glands, thyroid and gall-bladder in addition to the skin by histological, histochemical and ultrastructural studies. The amyloid deposits in these organs were of amyloid A protein type.

Adult↗
PubMed1995

The role of gsc and BMP-4 in dorsal-ventral patterning of the marginal zone in Xenopus: a loss-of-function study using antisense RNA.

The dorsal-specific homeobox gene goosecoid (gsc) and the bone morphogenetic protein 4 gene (BMP-4) are expressed in complementary regions of the Xenopus gastrula. Injection of gsc mRNA dorsalizes ventral mesodermal tissue and can induce axis formation in normal and UV-ventralized embryos. On the other hand, BMP-4 mRNA injection, which has a strong ventralizing effect on whole embryos, has been implicated in ventralization by UV, and can rescue tail structures in embryos dorsalized by LiCl. The above-mentioned putative roles for BMP-4 and gsc are based on gain-of-function experiments. In order to determine the in vivo role of these two genes in the patterning of the Xenopus mesoderm during gastrulation, partial loss-of-function experiments were performed using antisense RNA injections. Using marker genes that are expressed early in gastrulation, we show that antisense gsc RNA has a ventralizing effect on embryos, whereas antisense BMP-4 RNA dorsalizes mesodermal tissue. These loss-of-function studies also show a requirement for gsc and BMP-4 in the dorsalization induced by LiCl and in the ventralization generated by UV irradiation, respectively. Thus, both gain- and loss-of-function results for gsc and BMP-4 support the view that these two genes are necessary components of the dorsal and ventral patterning pathways in Xenopus embryos.

Animals↗
PubMed1995

Regulation of neural induction by the Chd and Bmp-4 antagonistic patterning signals in Xenopus.

In Drosophila the amount of neurogenic ectoderm, from which the central nervous system (CNS) derives, is regulated by a dorsal-ventral system of positional information in which two secreted molecules of antagonistic functions, decapentaplegic (dpp) and short-gastrulation (sog), play fundamental roles. The vertebrate homologue of dpp is either bmp-4 or bmp-2 (ref. 5), and the homologue os sog is chd (s-chordin). In Xenopus the CNS is induced by signals emanating from the organizer, and two proteins secreted by the organizer, noggin and follistatin, have been shown to induce neural tissue in animal-cap assays. Here we report that Chd, another organizer-specific secreted factor, has neuralizing activity and that this activity can be antagonized by Bmp-4. Inhibition of the function of the endogenous Bmp-4 present in the animal cap also leads to neural differentiation. We suggest that conserved molecular mechanisms involving chd/sog and bmp-4/dpp gene products pattern the ectoderm in Xenopus and in Drosophila.

Animals↗
PubMed1995

A conserved system for dorsal-ventral patterning in insects and vertebrates involving sog and chordin.

Dorsal-ventral patterning within the ectoderm of the Drosophila embryo requires seven zygotic genes, including short gastrulation (sog). Here we demonstrate that sog, which is expressed in the ventrolateral region of the embryo that gives rise to the nerve cord, is functionally homologous to the chordin gene of Xenopus, which is expressed in the dorsal blastopore lip of the embryo and in dorsal mesoderm, in particular the notochord. We show by injections of messenger RNA that both sog and chordin can promote ventral development in Drosophila, and that sog, like chordin, can promote dorsal development in Xenopus. In Drosophila, sog antagonizes the dorsalizing effects of decapentaplegic (dpp), a member of the transforming growth factor-beta family. One of the dpp homologues in vertebrates, bmp-4, is expressed ventrally in Xenopus and promotes ventral development. We show that dpp can promote ventral fates in Xenopus, and that injection of sog mRNA counteracts the ventralizing effects of dpp. These results suggest the molecular conservation of dorsoventral patterning mechanisms during evolution.

Amino Acid Sequence↗
PubMed1995

Keratin 14 gene point mutation in the Köbner and Dowling-Meara types of epidermolysis bullosa simplex as detected by the PASA method.

Recent advances in molecular biology have enabled the association of epidermolysis bullosa simplex (EBS) with point mutations of keratin 14 and/or keratin 5 genes to be established. We describe here the detection of point mutations in genomic DNA from formalin-fixed and paraffin-embedded sections from five cases of epidermolysis bullosa using the PCR amplification of specific alleles (PASA) method. In two of four cases of Köbner-type EBS a point mutation of helix 2b (384 Leu-Pro) was detected and in one case of Dowling-Meara-type EBS a mutation in helix 1a (125 Arg-Cys) was detected. The results of this study are consistent with previous reports and they demonstrate that the PASA method is a rapid and reproducible method for the detection of single-base changes and small deletions.

Alleles↗
PubMed1995

The incidence of internal malignancies in pemphigus and bullous pemphigoid in Japan.

To evaluate the significance of the association of malignancy with autoimmune blistering diseases, we studied the incidence of internal malignancies in pemphigus and bullous pemphigoid based upon 496 cases of pemphigus and 1113 cases of bullous pemphigoid in Japan. Results showed that (1) an association between internal malignancies and pemphigus was observed in 25 out of 496 cases (5.0%), while that with bullous pemphigoid was seen in 64 out of 1113 cases (5.8%). Such association ratios were significantly higher than that of the controls aged over 70 years old (0.61%); (2) The average ages of pemphigus/bullous pemphigoid with malignancy were 64.7 and 69.2 years, respectively. The association ratio of malignancy with pemphigus increased by age, while that with pemphigoid was not correlated with aging; (3) Lung cancer was most common in pemphigus and gastric cancer in bullous pemphigoid; (4) There were no significant differences in the titers of circulating antibody, the presence or extent of mucous involvement or annular erythema between bullous pemphigoid patients with malignancy and without malignancy. Our results indicated that detailed examination for internal malignancy is essential for those patients with pemphigus or bullous pemphigoid.

Aged↗
PubMed1995

Purification of human blood eosinophils by a combination method using anti-CD16 monoclonal antibody, immunobeads, and Nycodenz density gradient.

A simple method is described for the procurement of human blood eosinophil phenotypes by combining an anti-CD16 monoclonal antibody, immunobeads, and a non-toxic and non-ionic density gradient medium, Nycodenz. The purification depends on the removal of mononuclear cells using a 1.076/1.102 g/ml Nycodenz density gradient, partial removal of neutrophils based on different binding to plastic dishes, interaction of residual neutrophils with immunobeads via an anti-CD16 monoclonal antibody and, finally, extraction of eosinophil phenotypes by sifting the immunobeads-loaded neutrophils through an 1.080/1.102 g/ml Nycodenz density gradient. This method permits simultaneous preparation of highly purified normodense (> 1.080 g/ml) and hypodense eosinophils (< 1.080 g/ml) with reasonable chemiluminescence responses to opsonized zymosans and helminthotoxic activity to opsonized schistosomula corresponding to their own immunocytological properties.

Animals↗
PubMed1995

Polarization microscopic investigation of collagen and acid glycosaminoglycans in the skin of progressive systemic sclerosis (PSS).

Collagen and acid glycosaminoglycans in the skin of progressive systemic sclerosis (PSS) were examined by polarization microscopy. Picrosirius Red and Toluidine Blue (pH 5.8) were used as stains. Digestion with chondroitinase ABC or streptomyces hyaluronidase were also employed. Under polarized light, the Picrosirius Red-stained collagen appeared green at any stage in PSS and orange in controls. Toluidine Blue-induced birefringence at stage I diminished in the presence of 0.2 M MgCl2 and in stage II in the presence of 0.3 M MgCl2. The collagen fibrils in PSS skin were significantly smaller in diameter than in controls. These results suggest that the change of polarization colours is due to the modulation of collagen thickness caused by an increased accumulation of acid glycosaminoglycans.

Adult↗
PubMed1995

A flow cytometric analysis of the DNA content of Paget cells in the epidermis and the tumor of extramammary Paget's disease.

In the present study, we have examined whether or not the Paget cells in cases with dermal invasion or metastasis exhibit a different DNA distribution pattern to that seen in the epidermis in extramammary Paget's disease. The DNA contents of Paget cells from the epidermis and the tumor were determined by flow cytometry in two cases of extramammary Paget's disease with tumor formation, dermal invasion and metastases. The DNA histogram of Paget cells from the epidermis of two cases appeared to be close to the normal ploidy, whereas the histogram from the tumors was aneuploid in both cases. Our data suggest that the behavior of Paget cells in the epidermis is different from that in the tumor.

Aged↗
PubMed1995

Apoptosis identified by DNA fragmentation in epidermal neoplasms.

In the previous study, we demonstrated apoptotic cells in basal cell carcinomas by means of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). Positive staining cells were present at the peripheries and centers of the nests. The number of positive cells increased in cases showing deep infiltration. We also stained other epidermal neoplasms using this modified TUNEL method. In squamous cell carcinomas, many positive cells were observed in poorly differentiated types, but only a few cells were stained in well-differentiated types. TUNEL positive cells were rare in Bowen's disease. No positive cells were seen in seborrheic keratosis or verruca vulgaris. Our studies showed that apoptotic cells were more common in rapid growth neoplasms than in slow growth neoplasms.

Apoptosis↗
PubMed1995

Setleis' bitemporal "forceps marks" syndrome in a Japanese family.

Setleis' syndrome is an uncommon inherited condition characterized by bilateral "scarlike" depressions on the temples and a wide spectrum of associated facial abnormalities. We report on a typically affected Japanese boy, whose mother and grandfather show a much milder expression of this disorder, suggesting an apparent autosomal dominant inheritance.

Adult↗
PubMed1995

Proteoglycans in albo-papuloid lesions of the Pasini form of dominant dystrophic epidermolysis bullosa.

Epidermolysis bullosa is a group of inherited blistering diseases classified into three main sub-groups on the basis of the level of cleavage within the skin. In dominant dystrophic epidermolysis bullosa, characterized by cleavage below the basal lamina, two variants can be distinguished by the presence (Pasini form) or absence (Cockayne-Touraine form) of albo-papuloid lesions. The present study was undertaken to investigate the glycosaminoglycan chains of proteoglycans in the albo-papuloid lesions of a patient with the Pasini form, using histochemical and immunohistochemical methods. Histological examination revealed no dermo-epidermal separation. In the dermis, the papillary and subpapillary layers were slightly homogeneous, and exhibited a strong affinity towards alcian blue, which was abolished by treatment with chondroitinase ABC or in the presence of MgCl2 0.3M, but was resistant to digestion with streptomyces hyaluronidase. The papillary and subpapillary layers were intensely stained with a monoclonal antibody against small size proteoglycan with dermatan sulfate. These results suggest the presence of degraded dermatan sulfate proteoglycan in the papillary and subpapillary dermis of albo-papuloid lesions in the Pasini form of dystrophic epidermolysis bullosa.

Epidermolysis Bullosa Dystrophica↗
PubMed1995

Regulation of mammalian neural development by helix-loop-helix transcription factors.

Understanding of the molecular mechanisms of mammalian neural development has been greatly advanced by identification and characterization of the molecules homologous to the factors regulating Drosophila neurogenesis, which provides a powerful model system. Studies of Drosophila show that transcription factors with a helix-loop-helix (HLH) domain play an essential role in neurogenesis. Several lines of evidence demonstrate that mammalian homologues of the Drosophila HLH factors do also play an essential role in neural development. Mash-1, a mammalian HLH factor homologous to the products of Drosophila proneural genes achaete-scute complex, is a positive regulator of neurogenesis and required for differentiation of olfactory and autonomic neurons. In addition, HES-1, another mammalian HLH factor homologous to the products of Drosophila hairy and Enhancer of split, antagonizes the activity of Mash-1 and negatively regulates neurogenesis. Thus, positive and negative HLH factors interact with each other, and the balance between them is important for the developmental processes. Recent studies show that many other HLH factors exist expressed in the developing mammalian nervous system. In this article, the authors review mammalian HLH factors expressed in the nervous system and discuss the molecular aspect of mammalian neurogenesis.

Amino Acid Sequence↗