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D N Sauder

Publications and source records attributed to D N Sauder.

At least 73 records · Page 4Linked to original sources
PubMed1995

Effects of contact sensitizers neomycin sulfate, benzocaine and 2,4-dinitrobenzene 1-sulfonate, sodium salt on viability, membrane integrity and IL-1 alpha mRNA expression of cultured normal human keratinocytes.

The toxic effect of three potential contact sensitization chemicals [the aminoglycosidic antibiotic neomycin sulfate, the local anaesthetic benzocaine and the primary sensitizer 2,4-dinitrobenzene 1-sulfonate, sodium salt (DNBS)], on cultured human keratinocytes was examined. The three chemicals were compared with respect to their cytotoxic potential (determined by crystal violet staining assay), their membrane disruptive potential ([3H]arachidonic acid release assay), and their effects on interleukin 1 alpha (IL-1 alpha) mRNA expression [reverse transcription-polymerase chain reaction (RT-PCR)]. At the concentrations used, neomycin sulfate (0.004-0.32%) and benzocaine (0.0165-0.165%) did not show relevant cytotoxicity or membrane perturbation. On the other hand, DNBS (0.001-1%) caused a significant dose-dependent cytotoxic response at concentrations higher than 0.1%, while the [3H]arachidonic acid release assay indicated absence of membrane perturbation activity in all the range of DNBS concentrations examined. The effects of the three sensitizers on IL-1 alpha mRNA expression were varied; neomycin sulfate caused a dose-dependent induction of IL-1 alpha mRNA, benzocaine did not significantly affect its signal, and DNBS suppressed IL-1 alpha gene expression.

Arachidonic Acid↗
PubMed1995

A 40-100 MHz B-scan ultrasound backscatter microscope for skin imaging.

There is a growing interest in high resolution, subsurface imaging of cutaneous tissues using higher frequency ultrasound, and several commercial systems have been developed recently which operate at 20 MHz. Some of the possible applications of higher frequency skin imaging include tumour staging, boundary definition, and studies of the response of tumours to therapy, investigations of inflammatory skin conditions such as psoriasis and eczema, and basic studies of skin aging, sun damage and the effects of irritants. Investigation of these areas is quite new, and the role of ultrasound skin imaging is continuing to evolve. Lateral resolution in the 20 MHz imaging systems ranges from 200 to 300 microns, which limits imaging applications to cutaneous structures which are relatively large in size. In this paper, a real-time ultrasound backscatter microscope (UBM) for skin imaging is described which operates in the 40-100 MHz range, providing axial resolution between 17 and 30 microns and lateral resolution between 33 and 94 microns. This improvement in resolution over current skin ultrasound systems should prove useful in determining the margins of small skin lesions, and in obtaining more precise, in vivo skin thickness measurements to characterize nonmalignant skin disease. Example images of normal skin, seborrhoeic keratosis and malignant melanoma illustrate the imaging potential of this system.

Analog-Digital Conversion↗
PubMed1995

Expression of leukemia inhibitory factor and interleukin-11 by human melanoma cell lines: LIF, IL-6, and IL-11 are not coregulated.

Dysregulation in cytokines has been associated with melanomas. For example, loss of growth inhibition in advanced melanomas has been associated with interleukin-6 (IL-6) expression. Because IL-6 belongs to the hematopoietic cytokine family, which includes leukemia inhibitory factor (LIF) and interleukin-11 (IL-11), we examined the possibility of coordinate expression of LIF, IL-6, and IL-11 in three human melanoma cell lines derived from primary lesions (early) and in four lines derived from metastatic tumors (advanced). All lines examined produced at least low levels of LIF and IL-11 mRNA as measured by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). By enzyme-linked immunosorbent assay (ELISA), two of three early and three of four advanced lines were found to secrete LIF protein. IL-11 was assayed using growth of the responsive B9/11 cell line, but only one of seven lines made a low but measurable amount of IL-11. Cytokine protein production was not strictly correlated with mRNA abundance, nor was it strongly correlated with tumor staging. Recombinant LIF and IL-11 protein had no effect on the proliferation of any of the seven lines, suggesting that they do not act as autocrine growth factors for these melanomas. Assay of IL-6, IL-11, and LIF protein in conditioned medium from early and advanced melanoma lines gave no evidence of coordinate expression of these cytokines. We conclude that LIF and IL-11 production by melanomas may have some paracrine or endocrine function in the course of melanoma progression.

Base Sequence↗
PubMed1995

Does high-frequency (40-60 MHz) ultrasound imaging play a role in the clinical management of cutaneous melanoma?

The assessment of cutaneous melanoma in the clinical setting is often difficult, and important features such as depth and width remain unknown until the pathology report is received. Access to prognostic features such as vertical height before excisional biopsy would offer a basis for guidance in defining surgical margins and early planning of treatment options. Recently developed high-frequency ultrasound imaging in the 40-to 60-MHz range is a noninvasive method that provides in vivo information about cutaneous lesions. Imaging at these frequencies provides high-resolution data within the range of the epidermis and dermis (3-4 mm in depth). Ten cutaneous melanomas and seven pigmented lesions were assessed in this fashion. Vertical height was documented and compared to histopathological findings. High-frequency ultrasound imaging determination of vertical height correlated well with the standard measurement of Breslow's thickness on histological sections only in midrange (1.0-3.0 mm) lesions. Inflammatory cells at the base of three melanomas provoked an overestimation of the depth measurement with ultrasonography. Thick keratin layers such as those found on the feet acted as a virtual block to the high-frequency scanner. The application of this new advance in noninvasive imaging technology to the clinical assessment of cutaneous melanoma provides interesting in vivo data but in its present state does not replace the need for the biopsy of pigmented lesions and histopathological diagnosis.

Humans↗
PubMed1995

Interleukin-1 receptor antagonist suppresses contact hypersensitivity.

Interleukin-1 receptor antagonist (IL-1ra), a naturally occurring inhibitor of interleukin-1 (IL-1), blocks IL-1 binding to its receptors but has no agonistic activity. IL-1 is thought to play an important role in contact hypersensitivity (CHS), although the effects of exogenously administered IL-1 in CHS have been somewhat controversial. To clarify the role of IL-1 in CHS, we studied the effect of IL-1 receptor blockade using exogenous IL-1ra and evaluated these effects on CHS. We examined the in vivo effects of local administration of recombinant human IL-1ra in the murine CHS model. Local injection of IL-1ra to sensitized BALB/c mice just before challenge with dinitrofluorobenzene resulted in a significant reduction in the intensity of CHS responses, assessed by ear swelling. A dose-response study revealed that maximal inhibition of ear swelling (36% to 43%) was observed after intradermal injection of IL-1ra at doses of 10 to 100 micrograms/ear. This reduction in ear swelling in IL-1ra-injected ears consisted of less inflammatory cell infiltration and decreased edema in the dermis compared with controls. Suppression of CHS was observed when IL-1ra was applied in the 24-h interval preceding challenge with dinitrofluorobenzene, whereas no suppressive effect was observed when IL-1ra was applied 48 h before or after the challenge. Local administration of IL-1ra to naive mice 5 h before sensitization also suppressed CHS responses. However, IL-1ra injection did not suppress phenol-induced inflammation. These results suggest that IL-1ra is an effective inhibitor of both the sensitization and elicitation phases of CHS expression in mice, thus emphasizing the role of IL-1 as an immunologic potentiator of responses associated with CHS.

Animals↗
PubMed1995

Interleukin-1 alpha stimulates keratinocyte migration through an epidermal growth factor/transforming growth factor-alpha-independent pathway.

Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) stimulate keratinocyte migration on collagen by up-regulating the alpha 2 subunit of the collagen integrin, alpha 2 beta 1. Interleukin-1 (IL-1) is an autocrine factor, produced by keratinocytes themselves, that is modulated by ultraviolet light and increases the proliferative potential of keratinocytes in culture. The autocrine nature of keratinocyte-derived IL-1 alpha is emphasized by the fact that it induces the keratinocyte to synthesize IL-1 alpha and TGF-alpha, a cytokine known to induce keratinocyte motility. Further, topical application of IL-1 alpha has been shown to promote wound healing in animals. In this study, we used a well-defined keratinocyte migration assay to assess the effect of IL-1 alpha on keratinocyte motility and to examine whether the IL-1 alpha/TGF alpha pathway is involved. The addition of recombinant human IL-1 alpha to keratinocytes produced a statistically significant and concentration-dependent increase in migration on matrices of collagen types I and IV, but not on laminin. Maximal levels of keratinocyte migration obtained on these matrices with IL-1 alpha were comparable to those obtained with stimulation by EGF and TGF-alpha. The effects of TGF-alpha and IL-1 alpha on keratinocyte migration are additive; however, the maximal level of migration achieved by using IL-1 alpha and TGF-alpha in combination never exceeds the maximal level of migration found by using either cytokine alone. The time course of keratinocyte migration induced by IL-1 alpha is delayed (onset of migration 9-12 h after addition) as compared with that induced by TGF-alpha (onset of migration 6-9 h after addition) even if the cells are preincubated in IL-1 alpha. Flow cytometry analysis demonstrated no change in surface expression of integrin subunits, specifically that of integrin subunit alpha 2, previously shown to be up-regulated by EGF/TGF-alpha. These results suggest that IL-1 alpha stimulates keratinocyte migration on collagen via a mechanism distinct from that of EGF/TGF-alpha.

Cell Movement↗
PubMed1995

Failure to detect interleukin (IL)-3 mRNA or protein in human keratinocytes: antibodies to granulocyte macrophage-colony-stimulating factor or IL-6 (but not IL-3) neutralize "IL-3" bioactivity.

Interleukin (IL)-3-like bioactivity has been found in culture supernatants from human and murine keratinocytes. However, there is controversy as to the presence of IL-3 mRNA in human keratinocytes. Using highly sensitive reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay techniques, we examined human keratinocytes from four different donors (neonatal foreskins) and were unable to detect IL-3 mRNA or IL-3 protein. Despite successful amplification of DNA from an IL-3 cDNA, no product could be obtained by amplification of keratinocyte RNA treated with reverse transcription-polymerase chain reaction. Analysis of concentrated (up to 50-fold) supernatants failed to detect IL-3 protein by enzyme-linked immunosorbent assay. Because ultraviolet radiation up-regulates many cytokines, we irradiated human keratinocytes with 300 J/m2 ultraviolet B and collected supernatants 24 h post-irradiation. Supernatants concentrated 50-fold were also negative for IL-3 protein by enzyme-linked immunosorbent assay. When assayed on the IL-3-responsive M-07e cell line, unirradiated supernatants stimulated M-07e proliferation 22-fold over background levels. Irradiated supernatants stimulated M-07e proliferation 128-fold. Neither the unirradiated nor the irradiated supernatant activity could be neutralized with antibody to human IL-3. However, incubation of irradiated supernatants with antibody to granulocyte macrophage-colony-stimulating factor (GM-CSF) reduced the M-07e proliferation by 90%. Antibodies against GM-CSF and IL-6 completely abrogated proliferation. Reverse transcription-polymerase chain reaction confirmed a concomitant elevation of IL-6 (2.6- to 5.6-fold) and of GM-CSF mRNA (2.7- to 4.3-fold) at 6 and 24 h after ultraviolet B irradiation in keratinocytes, but no IL-3 amplification products could be detected. IL-3 mRNA was also not detected in adult keratinocytes. Even after stimulation by IL-1 alpha, tumor necrosis factor-alpha, or phobol myristate acetate, IL-3 mRNA was not detected in either neonatal or adult human keratinocytes. We have been unable to detect IL-3 mRNA or IL-3 protein in human keratinocytes. The IL-3-like activity in human keratinocytes is mainly due to GM-CSF, with a small contribution from IL-6.

Antibodies↗
PubMed1995

Keratinocyte-derived cytokines and UVB-induced immunosuppression.

Ultraviolet radiation (UVB) in sunlight is known to have multiple effects on the immune system. Evidence suggests that UVB-induced immunosuppression is mediated in part by immunosuppressive and immunoregulatory cytokines. Our studies have utilized gene-targeted mutant mice to determine key molecular requirements essential for the development of UVB-induced immunosuppression. Preliminary results from our laboratory suggest that TNF-alpha plays a regulatory role in contact hypersensitivity, but is not a crucial factor for UVB-induced immunosuppression, and that multiple factors are involved in the induction of UVB mediated immunosuppression.

Animals↗
PubMed1995

Interleukin-8 and melanoma growth-stimulating activity (GRO) are induced by ultraviolet B radiation in human keratinocyte cell lines.

Ultraviolet radiation can induce the transcription and release of cytokines from keratinocytes (KC's). These cytokines have the potential to modulate local and systemic immunologic responses. In this paper we report that northern blotting showed that human KC and KC lines expressed a 1.2-1.4 kb transcript for the chemokine and melanoma growth-stimulatory protein, GRO-alpha and that ultraviolet B radiation (UVB) could upregulate the expression of GRO-alpha mRNA and protein in the KC line A431. The GRO-alpha gene response to UVB was maximal at 48h post-irradiation with 70 J/m2. Reverse transcription-polymerase chain reaction (RT-PCR) revealed a 4.5-fold increase in GRO-alpha mRNA over basal levels (p < 0.001). GRO-alpha protein was measured in the culture media by enzyme-linked immunosorbent assay (ELISA). Media from unirradiated cultures contained 1166 +/- 83 pg/ml GRO-alpha protein. After UVB, a time-dependent increase in GRO-alpha protein was seen in the culture media from 6-48h. At 48h post-irradiation the GRO-alpha protein content was 27583 +/- 678 pg/ml, or 23 times the basal level. This protein release could be inhibited by 70% when the cells were pre-incubated with 10 micrograms/ml interleukin-1 receptor antagonist (IL-1RA). We also show that another potent leukocyte chemoattractant, Interleukin-8 (IL-8), was induced in A431 cells by UVB. This induction of IL-8 mRNA began as early as 3h post-irradiation, when it reached twice basal levels (p < 0.05) and reached 4.5-fold basal levels at 48h post-irradiation (p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1995

Inhibition of cytokine gene expression in mouse skin by subcutaneous injection of cyclosporine.

Cyclosporine A (CsA) has been shown to be an effective therapeutic agent for a wide variety of cutaneous diseases yet its exact mechanism of action is still unclear, although one well-defined effect of CsA is the inhibition of T-cell-derived cytokine expression. We recently demonstrated in vitro that CsA inhibits cell proliferation and suppresses cytokine gene expression in keratinocytes. In this study, we report the in vivo effects of CsA on skin cytokine gene expression as determined by reverse-transcriptase polymerase chain reaction. C57BL6 mice (female, 8-10 weeks old) were subcutaneously injected with CsA in olive oil (0, 5 and 10 mg/kg) every other day for 3 weeks. Treatment with 5 mg/kg CsA inhibited both interleukin (IL)-1 alpha and tumor necrosis factor alpha gene expression by about 70 and 90%, respectively, relative to vehicle control levels. However, IL-6 gene expression did not significantly change. Injection of 10 mg/kg CsA inhibited expression of all three genes by 80-90% relative to control levels. These data show that CsA can inhibit constitutive cytokine gene expression in mouse skin.

Animals↗
PubMed1995

In vitro and in vivo percutaneous absorption of 14C-chloroform in humans.

Chloroform has been found in potable water and there is concern that significant dermal absorption may arise from daily bathing and other activities. The present study examines percutaneous absorption of 14C-chloroform in vivo using human volunteers and in vitro using fresh, excised human skin in a flow-through diffusion cell system. Fifty microlitre doses of either 1000 micrograms ml-1 chloroform in distilled water, (16.1 micrograms cm-2) or 5000 micrograms ml-1 of chloroform in ethanol, (80.6 micrograms cm-1) were applied to the forearm of volunteers with exhaled air and urine being collected for analysis. Single doses of either 0.4 microgram ml-1 chloroform in distilled water (low dose, 0.62 microgram cm-2, 1.0 ml dosed) or 900 micrograms ml-1 chloroform in distilled water (high dose, 70.3 micrograms cm-2, 50 microliters dosed) were applied to discs of the excised abdominal skin placed in flow-through diffusion cells and perfused with Hepes buffered Hank's balanced salt solution, with a wash at 4 h. In vivo absorption was 7.8 +/- 1.4% (water as vehicle) and 1.6 +/- 0.3% (ethanol as vehicle). Of the dose absorbed in vivo, more than 95% was excreted via the lungs (over 88% of which was CO2), and the maximum pulmonary excretion occurred between 15 min and 2 h after dosing. The percentage of dose absorbed in vitro (skin+perfusate) was 5.6 +/- 2.7% (low dose) and 7.1 +/- 1.4% (high dose). The above data demonstrate that a significant amount of the dissolved chloroform penetrates through the human skin, and that a higher percentage of the applied dose was absorbed using water as vehicle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A role for CD4+ T cells in the pathogenesis of skin fibrosis in tight skin mice.

The tight skin (Tsk/+) mouse represents a murine model of heritable fibrosis with some similarities to the skin fibrosis seen in human scleroderma. Tsk/+ animals display alterations in connective tissue in some internal organs. Skin fibrosis can be adoptively transferred to normal recipients with Tsk/+ bone marrow or spleen cells and older Tsk/+ animals develop autoantibodies against topoisomerase suggesting that some of the pathogenesis in the Tsk/+ mouse may be mediated by autoimmunity. To determine the role of T cell subsets in the pathogenesis of fibrotic disease, Tsk/+ mice were bred with CD4- and CD8-deficient (CD4-/- and CD8-/-) mice. Tsk/+ CD4-/- mice showed a marked reduction in skin fibrosis as well as decreased cellularity and only mild collagen disorganization as compared to Tsk/+ CD4+ CD8+ control mice yet did not differ from Tsk controls in the level of serum anti-topoisomerase activity. In contrast, Tsk/+ CD8-/- mice exhibited the same histology in the skin as Tsk/+ controls yet had significantly reduced levels of serum anti-topoisomerase activity. Lung pathology, i.e. emphysema, was unaffected by both the CD4 or CD8 mutations. These data show that only some of the pathological effects of the Tsk mutation are T cell dependent and that different T cell subsets affect different parameters in this multi-organ model of fibrotic disease.

Animals↗
PubMed1994

Antifungal agents: an overview. Part II.

The recent introduction of a new generation of antifungal drugs promises to alter significantly therapy for both systemic and superficial mycoses, in particular, onychomycosis. This article presents an in-depth review of the azoles (the triazoles itraconazole and fluconazole), the allylamines (naftifine and terbinafine), and the morpholine derivative amorolfine.

Allylamine↗
PubMed1994

Synthesis of interleukin-1 alpha and beta by normal human melanocytes.

Normal human melanocytes and melanoma cells have been reported to produce several cytokines. Previously we demonstrated that neonatal human melanocyte proliferation and tyrosinase activity are inhibited by interleukin-1 alpha, tumor necrosis factor-alpha, and interleukin-6. We have now also shown that interleukin-1 beta induces an inhibiting effect on neonatal melanocyte tyrosinase activity with little effect on melanocyte proliferation. We investigated the ability of neonatal and adult human melanocytes to synthesize interleukin-1 alpha and beta. By immunocytochemistry, using monoclonal antibodies against interleukin-1 alpha and beta, we observed that neonatal and adult melanocytes stain positively for both cytokines. Flow-cytometric analysis revealed that the percentage of melanocytes positive for interleukin-1 alpha was always greater than that for interleukin-1 beta. The ability of neonatal and adult melanocytes to synthesize interleukin-1 alpha and beta was further confirmed using the polymerase chain reaction. These results clearly indicate that human melanocytes synthesize interleukin-1 alpha and beta, and that these cytokines may function as autocrine and/or paracrine regulators of cells in the epidermis.

Adult↗
PubMed1994

Interleukin-10 inhibits the elicitation phase of allergic contact hypersensitivity.

Interleukin-10 (IL-10) is known to play a major role in suppressing immune and inflammatory responses by inhibiting the production of proinflammatory cytokines. Therefore, we hypothesized that IL-10 might be capable of suppressing allergic contact hypersensitivity. BALB/c mice were sensitized on the dorsal skin with dinitrofluorobenzene and challenged on the ears 6 d later. The effect of IL-10 on the elicitation phase of contact sensitization was determined by its intradermal injection into the pinnae of the mice at doses of 0.1-100 ng. At 24 and 48 h after challenge, ear swelling was suppressed in a dose-dependent manner by injection of IL-10 at doses of 10-100 ng. Maximal inhibition of ear swelling (46.9%) was observed after injection of 100 ng of IL-10. IL-10-injected ear skins showed less inflammatory cell infiltration and decreased edema at the dermis compared with controls. Because IL-10 is known to inhibit Th1 cytokines such as interferon-gamma, we examined whether the suppressive effect of IL-10 on ear swelling was accompanied by IL-10-induced inhibition of interferon-gamma. We found that IL-10 application suppressed interferon-gamma mRNA upregulation in challenged skin. Our results suggest that IL-10 significantly modifies the elicitation of allergic contact sensitivity reactions.

Animals↗
PubMed1994

Ultraviolet irradiation downregulates the IL-1 receptor in Pam 212 keratinocytes.

There is increasing evidence that keratinocytes, by virtue of production of cytokines, may participate in inflammatory and immune responses in the skin. The expression of keratinocyte cytokines can be modulated by various exogenous and endogenous agents, including ultraviolet light (UV) and cytokines themselves. We have recently shown that augmentation of GM-CSF expression by UVB irradiation is mediated by UV-induced IL-1 in Pam 212 keratinocytes. This may suggest that an autocrine mechanism exists in this murine keratinocyte cell line. In order to further clarify the mechanism by which UV irradiation augments GM-CSF, this study was undertaken to assess the effect of UV on the expression of IL-1 receptor (IL-1R) in Pam 212 keratinocytes. UVB irradiation (35 or 70 J/m2) significantly downregulates the expression of IL-1R mRNA. IL-1R mRNA remains downregulated for 12h after UV, then slowly returns to the steady state level by 24h to 32h after UV. On the other hand, UV augments IL-1 mRNA in a biphasic pattern with an initial phase (by 6h after UV) and a late phase (24h and 48h after UV). The results of these studies indicate that modulation of IL-1R and IL-1 itself by UVB irradiation are important in mediating autocrine cytokine networks in keratinocytes.

Down-Regulation↗
PubMed1994

Cyclosporin A inhibits keratinocyte cytokine gene expression.

The immunosuppressive peptide cyclosporin A (CyA) is an extremely effective therapy for severe recalcitrant psoriasis, although its mechanism of action is unknown. In this study, we examined the effect of CyA on keratinocyte growth and cytokine expression, and showed that CyA inhibits the growth of murine and human keratinocytes (KC) and KC cell lines. In addition, CyA inhibits the expression of cytokine genes in a dose-dependent fashion. After 2 days' incubation with 20 microM CyA, interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), and interleukin 8 (IL-8) mRNA were decreased by 4-fold, 3.3-fold and 3.3-fold, respectively, in COLO-16, a keratinocyte cell line. IL-1 biological activity recovered from COLO-16 culture supernatants decreased to one-fifth of that of controls. In the murine KC cell line PAM 212, 10 microM CyA treatment for 2 days downregulated IL-1 alpha, tumour necrosis factor-alpha (TNF-alpha) and IL-1 receptor by 60%, but had no effect on the message for interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), ornithine decarboxylase and beta-actin. Cells cultured for 5 days in the presence of CyA required much lower concentrations (2 microM) to achieve the same degree of inhibition of IL-1 alpha. Similar tissue concentrations of CyA have been reported in psoriatics undergoing CyA therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗