Biomedical subjects

M Denda

Publications and source records attributed to M Denda.

At least 19 recordsLinked to original sources

PubMed2001

Immunoreactivity of VR1 on epidermal keratinocyte of human skin.

We demonstrated the immunoreactivity of the receptor proteins, VR1, ion channels associated with pain sensation, on the epidermis of the human skin. Immunohistochemistry using antiserum against VR1 derived peptide showed immunoreactivity on the keratinocytes cell membrane of the human epidermis and cultured keratinocytes. The blocking peptide of the antiserum reduced the immunoreactivity on the epidermis. RT-PCR assay of cultured human keratinocyte also showed expression of VR1 mRNA. These results suggest the existence of VR1-like protein in epidermal keratinocytes of human skin.

Adult↗

PubMed2001

Skin surface electric potential induced by ion-flux through epidermal cell layers.

The skin surface electric potential has been widely used for psychological studies because it is sensitive to emotional conditions. We measured the electric potential on the surface of hairless mice skin in organ culture with several physiological factors. Disruption of mitochondrial function and inhibition of ATPase reduced the skin surface potential 50-70%. Calcium, potassium, and sodium channel blockers also reduced the potential. A calcium-specific and potassium ionophore reduced the potential, but the calcium and magnesium ionophore increased it. EDTA decreased the potential but EGTA had no effect. Skin surface barrier disruption reduced the potential and calcium and potassium channel blockers partially prevented the decrease. Substance P and corticotropin-releasing factor decreased the potential, and antagonists blocked the decreases. These results suggest that the ion flux in the nucleated layer of the epidermis induce the skin surface potential and it is influenced by environmental and neuroendocrinological factors.

4-Aminopyridine↗

PubMed2001

Identification of immature cornified envelopes in the barrier-impaired epidermis by characterization of their hydrophobicity and antigenicities of the components.

Cornified envelopes (CEs), rigid and insoluble structures in the stratum corneum, which are assembled by crosslinking of several precursor proteins by transglutaminases, provide a hydrophobic foundation for barrier function; omega-hydroxyceramides are covalently attached to the outer surface of CE components, and onto this hydrophobic assembly, lamellar layers of intercellular lipids are organized. Morphologically irregular, fragile CEs are found in the deep layer of the stratum corneum or in certain disorders, such as psoriasis, whereas most CEs from healthy subjects are rigid and polygonal. We have established a staining method to characterize such fragile CEs as immature and less hydrophobic CEs, and employed it to examine regional differences in the properties of CEs, especially in relation to the barrier function of the skin. CEs from the outermost stratum corneum of the trunk and extremities of healthy subjects were relatively uniform in morphology with larger shape, and were homogeneous in hydrophobicity as judged from the use of an environment-sensitive fluorescent dye, Nile red. However, CEs from the face were strikingly heterogeneous, and consisted of both rigid and fragile CEs. Rigid CEs were Nile red-positive and little stained by anti-involucrin. In contrast, fragile CEs were Nile red-negative but strongly stained with anti-involucrin, as detected by indirect immunofluorescence. Thus, CEs from the face were stained with Nile red or involucrin in a mutually exclusive manner. Fragile CEs were stained with antibodies against other CE components, including loricrin, envoplakin, filaggrin, and isopeptides. Such fragile, involucrin-positive CEs were detected not only in the face, but also in the deep layer of the stratum corneum of the arm. In addition, experimental barrier disruption resulted in the appearance of involucrin-positive CEs in the outermost stratum corneum. These results suggest that involucrin-positive, fragile CEs are immature and less hydrophobic, and that their occurrence is closely related to impairment of the barrier function of the skin.

Cell Membrane Permeability↗

PubMed2001

Epidermal interleukin-1 alpha generation is amplified at low humidity: implications for the pathogenesis of inflammatory dermatoses.

BACKGROUND: We have previously reported that low humidity amplifies the hyperproliferative and inflammatory response to barrier disruption. Other reports suggest that epidermal interleukin (IL)-1 alpha is stimulated by various factors related to epidermal inflammation and that it may induce other proinflammatory molecules. OBJECTIVES: To evaluate the generation of IL-1 alpha in the skin of hairless mice kept under various conditions of environmental humidity. METHODS: We carried out an immunohistochemical study, and evaluated epidermal IL-1 alpha mRNA and protein levels, and release of IL-1 alpha from skin after tape stripping, in hairless mice kept under low or high humidity. RESULTS: The immunohistochemical study showed that the amount of IL-1 alpha in the epidermis was higher in animals kept in a low-humidity environment than in a high-humidity one. The epidermal IL-1 alpha mRNA and protein levels increased significantly when the animals were kept under low humidity. Moreover, the release of IL-1 alpha from skin immediately after tape stripping was significantly higher in animals kept in a low-humidity environment than in a high-humidity one. CONCLUSIONS: These results suggest that IL-1 alpha is an important factor in mediating the relationship between environmental humidity and epidermal pathology.

Animals↗

PubMed2001

Epidermal proliferative response induced by sodium dodecyl sulphate varies with environmental humidity.

BACKGROUND: Previous studies have suggested that susceptibility of skin to external agents increases in the dry winter season. OBJECTIVES: To test the hypothesis that environmental humidity affects skin sensitivity to irritants. METHODS: The epidermal hyperplasia induced by sodium dodecyl sulphate (SDS) under various humidity conditions was evaluated on the skin of hairless mice. RESULTS: Mice kept under low humidity for 2 days showed more obvious epidermal proliferation 24 h after topical application of SDS than those kept under high or normal humidity for 2 days. In contrast, mice kept under high humidity for 2 weeks showed more obvious epidermal proliferation 24 h after topical application of SDS than those kept under low or normal humidity. The transepidermal water loss was altered significantly in the animals kept under high humidity for 2 weeks, although it was not altered during the first 7 days under either low or high humidity. CONCLUSIONS: These results suggest that environmental humidity influences the sensitivity of skin to topical application of SDS and that increased sensitivity is not always associated with alteration of the water impermeability of the stratum corneum.

Analysis of Variance↗

PubMed2001

Histamine H1 and H2 receptor antagonists accelerate skin barrier repair and prevent epidermal hyperplasia induced by barrier disruption in a dry environment.

Keratinocytes have histamine H1 and H2 receptors, but their functions are poorly understood. To clarify the role of histamine receptors in the epidermis, we examined the effects of histamine receptor antagonists and agonists applied epicutaneously on the recovery of skin barrier function disrupted by tape stripping in hairless mice. Histamine H2 receptor antagonists famotidine and cimetidine accelerated the recovery of skin barrier function, but histamine and histamine H2 receptor agonist dimaprit delayed the barrier repair. Application of compound 48/80, a histamine releaser, also delayed the recovery. Imidazole, an analog of histamine, had no effect. The histamine H1 receptor antagonists diphenhydramine and tripelennamine accelerated the recovery. Histamine H3 receptor agonist Nalpha-methylhistamine and antagonist thioperamide had no effect. In addition, topical application of famotidine or diphenhydramine prevented epidermal hyperplasia in mice with skin barrier disrupted by acetone treatment in a dry environment (humidity < 10%) for 4 d. In conclusion, both the histamine H1 and H2 receptors in the epidermis are involved in skin barrier function and the cutaneous condition of epidermal hyperplasia.

Animals↗

PubMed2001

A Brassica oleracea gene expressed in a variety-specific manner may encode a novel plant transmembrane receptor.

The species Brassica oleracea includes several agricultural varieties characterized by the proliferation of different types of meristems. Using a combination of subtractive hybridization and PCR (polymerase chain reaction) techniques we have identified several genes which are expressed in the reproductive meristems of the cauliflower curd (B. oleracea var. botrytis) but not in the vegetative meristems of Brussels sprouts (B. oleracea var. gemmifera) axillary buds. One of the cloned genes, termed CCE1 (CAULIFLOWER CURD EXPRESSION 1) shows specific expression in the botrytis variety. Preferential expression takes place in this variety in the meristems of the curd and in the stem throughout the vegetative and reproductive stages of plant growth. CCE1 transcripts are not detected in any of the organs of other B. oleracea varieties analyzed. Based on the nucleotide sequence of a cDNA encompassing the complete coding region, we predict that this gene encodes a transmembrane protein, with three transmembrane domains. The deduced amino acid sequence includes motifs conserved in G-protein-coupled receptors (GPCRs) from yeast and animal species. Our results suggest that the cloned gene encodes a protein belonging to a new, so far unidentified, family of transmembrane receptors in plants. The expression pattern of the gene suggests that the receptor may be involved in the control of meristem development/arrest that takes place in cauliflower.

Amino Acid Sequence↗

PubMed2000

Visual imaging of ion distribution in human epidermis.

The distribution of calcium, magnesium, potassium, sodium, and hydrogen ions in the human epidermis was visualized by blotting to gel containing chemical indicators and the effects of skin barrier disruption were examined. In normal skin, both calcium and magnesium were localized with high concentration in the upper epidermis. EDTA blocked these imaging. The hydrogen ion was also high in the upper epidermis. Sodium did not show obvious gradation in the epidermis. The potassium concentration was the lowest in the upper epidermis. After the barrier disruption, the gradients of calcium, magnesium, and potassium disappeared while the pH gradation was not altered. Observation at a high magnification revealed lower calcium and sodium concentrations in the nucleus. The concentration of magnesium was slightly higher in the nucleus. The novel method of the present study could show the visual image of the ions in frozen tissue without further preparation.

Calcium↗

PubMed2000

Changes in levels of biochemical markers and ultrasound indices of Os calcis across the menopausal transition.

The aim of this longitudinal study was to investigate the changes in the levels of biochemical markers and ultrasound indices of os calcis across the menopausal transition. One hundred and ten healthy women (age 35-59 years at the 1992 baseline) participated in this 4-year population-based longitudinal study. Serum intact osteocalcin (IOC), urinary pyridinoline (Pyr), urinary deoxypyridinoline (Dpyr) and ultrasound indices were measured at baseline and after 4 years. The percentage changes in biochemical markers (% delta IOC, % delta Pyr and % delta Dpyr) and the percentage decreases in the ultrasound indices (% delta SOS, % delta BUA and % delta Stiffness) were calculated. The values of % delta IOC and % delta Dpyr in the perimenopausal subgroup (-4 to -3 years since menopause) and the values of % delta SOS and % delta Stiffness in the perimenopausal subgroup (-2 to 0 years since menopause) were significantly higher than those in other groups. Pyr was significantly correlated with % delta SOS (r = -0.467, p < 0.01) and % delta Stiffness (r = -0.330, p < 0.05) and Dpyr was significantly correlated with % delta SOS (r = -0.390, p < 0.05), % delta BUA (r = -0.353, p < 0.05) and % delta Stiffness (r = -0.454, p < 0.05), while % delta IOC was significantly correlated with % delta SOS (r = -0.278, p < 0.05), % delta BUA (r = -0.369, p < 0.01) and % delta Stiffness (r = -0.383, p < 0.01) in the peri- and postmenopausal groups. These results indicate that the increase in bone turnover occurs 4 years before menopause. However, the correlations between biochemical markers and ultrasound indices were too low to allow prediction of bone change in the individual patient.

Adult↗

PubMed2000

Water content and thickness of the stratum corneum contribute to skin surface morphology.

Skin surface morphology has long been recognized as reflecting skin pathology. In the present study, we evaluated skin surface morphology using hairless mice under contrasting conditions of humidity. The skin surface microrelief was recorded with opaque quick-drying silicone rubber, and examined under a microscope. A binary image was produced by density slicing. Within 3 days of exposure to dry conditions, skin roughness was significantly increased. The skin roughness was partially mitigated by topical application of an aqueous solution of glycerol or hydration by immersion in water. A significant correlation between skin roughness and stratum corneum thickness was also observed. These results suggest that skin surface morphology is associated with both water content and thickness of the stratum corneum.

Administration, Topical↗

PubMed2000

Influence of dry environment on epidermal function.

Recent studies have demonstrated that a dry environment contributes to the exacerbation of cutaneous disorders such as epidermal hyperplasia, mast cell degranulation, and cytokine secretion. The effects of a dry environment on the skin can be prevented by occlusion with water-impermeable material or topical application of a humectant. The stratum corneum, which protects internal organs from the environment, has two functions: a water-impermeable barrier function and a buffer function against a dry environment. Regulation of protease activity or ionic balance in the epidermis can accelerate barrier repair after injury. Improvement of the stratum corneum homeostasis can ameliorate skin damage induced by barrier disruption in a dry environment.

Animals↗

PubMed2000

Regulation of the cutaneous allergic reaction by humidity.

Humidity is 1 of the environmental factors which regulate skin conditions. Effects of humidity on the cutaneous immune reaction were examined. Contact hypersensitivity to 2,4,6-trinitrochlorobenzene was elicited in C57BL/6 mice. The reaction was greater in mice housed under low humidity conditions (about 10%) for 2 days, at either the induction or elicitation phase, than in mice housed under rather high humidity conditions (80%). After housing under controlled humidity for 2 days, the number of I-A positive cells was 16% higher in the epidermis exposed to the dry condition. The increased population of FITC-positive cells were in regional lymph nodes after painting of FITC during housing under lower humidity. Our study demonstrated that the cutaneous immune reaction is regulated by environmental humidity and suggested 2 possible mechanisms, i.e., increase in Langerhans cells and increased penetration of allergen with low humidity.

Allergens↗

PubMed2000

Barrier recovery rate varies time-dependently in human skin.

The recovery in cutaneous barrier functions, assessed in terms of transepidermal water loss, 1 h after tape stripping of volar forearm skin in human volunteers, was investigated at different times over the 24 h day. The barrier recovery rate was significantly lower between 20:00 h and 23:00 h than that at other time points. The skin surface temperature and the basal transepidermal water loss reached their highest values at about 03:00 h (33.6 degrees C and 0.30 mg cm-2 h-1), while the cortisol level in the saliva was highest at 09:00 h (7.8 pmol mL-1). These results suggest significant time-dependent variation in cutaneous barrier repair independent of changes in skin temperature and cortisol level.

Adult↗

PubMed2000

Odorant inhalation affects skin barrier homeostasis in mice and humans.

Previous studies have suggested that psychological stress delays cutaneous barrier recovery following acute barrier disruption, and that sedative drugs block this delay. A sedative effect of some odorants has been reported. In the present study, we demonstrate that odorant inhalation affects cutaneous barrier homeostasis in both mice and humans. Odorants with a sedative effect prevented the delay of skin barrier recovery induced by stress after acute barrier disruption. Other odorants did not show this effect.

Administration, Inhalation↗

PubMed2000

Stress alters cutaneous permeability barrier homeostasis.

Recent studies have shown that psychological stress can influence cutaneous barrier function, suggesting that this form of stress could trigger or aggravate skin disease. In the present study, we demonstrate that transfer of hairless mice to a different cage delays barrier recovery rates. Pretreatment with a phenothiazine sedative, chlorpromazine, before transfer of animals restored the kinetics of barrier recovery toward normal, suggesting that psychological stress is the basis for this alteration in barrier homeostasis. To determine the mechanism linking psychological stress to altered barrier recovery, we first demonstrated that plasma corticosterone levels increase markedly after transfer of animals to new cages and that pretreatment with chlorpromazine blocks this increase. Second, we demonstrated that the systemic administration of corticosterone delays barrier recovery. Finally, we demonstrated that pretreatment with the glucocorticoid receptor antagonist RU-486 blocks the delay in barrier recovery produced by systemic corticosterone, change of cage, or immobilization. These results suggest that psychological stress stimulates increased production of glucocorticoids, which, in turn, adversely affects permeability barrier homeostasis.

Animals↗

PubMed1999

Some magnesium salts and a mixture of magnesium and calcium salts accelerate skin barrier recovery.

The effects of four different magnesium salts on the cutaneous barrier recovery rate after barrier disruption were evaluated. We spread an aqueous solution of each salt on the flank skin of hairless mice, occluded the area with a plastic membrane for 20 min, and then left the skin surface to dry. All of the magnesium salts, except magnesium bis(dihydrogen phosphate), accelerated barrier repair. We next estimated the effects of magnesium chloride aqueous solutions which contained calcium chloride at different molar ratios. When the calcium to magnesium ratio was lower than 1, the mixture accelerated barrier repair. The application of an aqueous solution of 10 mM magnesium chloride and 10 mM calcium chloride was found to hasten the barrier recovery more effectively than a solution of 10 mM magnesium chloride. These results suggest that the effects of these metal ions are different depending on the counter ion and/or the method of application.

Animals↗

PubMed1998

Loss of water from the stratum corneum induces epidermal DNA synthesis in hairless mice.

Many clinical studies have shown that low humidity has a deleterious effect on skin, but the mechanisms involved are poorly understood. To clarify the changes that occur in skin, we examined epidermal cell proliferation in mice kept in a dry (relative humidity < 10%) or a moist (relative humidity > 90%) environment. In animals exposed to low humidity, epidermal DNA synthesis started to increase within 12 h, reaching twice the original level, and the increased level was maintained for up to 5 days. The transepidermal water loss (TEWL) of mice kept for 12 h in the dry environment was the same as that of mice kept in the moist environment, but the skin conductance was lower. The increase in epidermal DNA synthesis following exposure to the dry environment was inhibited by topical application of petrolatum. It is concluded that loss of water from the stratum corneum induces epidermal cell proliferation within 12 h, and this change occurs in the absence of apparent cutaneous barrier dysfunction.

Animals↗

PubMed1998

Dry condition affects desquamation of stratum corneum in vivo.

We examined whether a dry condition actually induces scaly skin in vivo. Hairless mice were kept in a high humidity condition or a low humidity condition and skin changes were examined. Scales appeared on the backs of mice kept for 3 days under the dry condition. The weight of stratum corneum (SC) was increased at this point, and these alterations were not accompanied with hyperproliferation of the nucleated cell layer of the epidermis. A decrease of desmosomal degradation was observed, though, desquamation-related enzyme activity was not altered. The regulation mechanism of desquamation is not yet clear, however, in vitro experiments suggest that the water content in SC is an important factor. The water content of SC was decreased in the dry condition. These results indicate that a dry environment perturbs desmosome degradation in intact SC by decreasing the water content of SC, and the consequent impairment of desquamation in normal skin in vivo may lead to the induction of a scaly skin surface.

Animals↗