Arachidonic acid metabolism in primary irritant dermatitis produced by patch testing of human skin with surfactants.

A clinical study was performed to determine the effects of patch testing human skin with four industrially used surfactants on erythema formation, transepidermal water loss, and the contents in suction blister fluids of primary proinflammatory mediators including arachidonic acid, eicosanoids, and IL-1 alpha, which were analyzed by quantitative gas chromatography/negative ion chemical ionization mass spectrometry and by an enzyme-immunoassay, respectively. Benzalkonium chloride (BKCI) and sodium lauryl sulfate (SLS) elicited erythema and caused increased transepidermal water loss, indicating a disturbance of the epidermal barrier. Triethanolamine (TEA) and Tween 80 did not evoke these gross symptoms of inflammation.

Arachidonic acid metabolism as a reporter of skin irritancy and target of cancer chemoprevention.

Keratinocytes respond to skin irritation and injury by cytokine release and a rapid but transient activation of arachidonic acid metabolism along both the cyclooxygenase and lipoxygenase pathways. In the first part of this article results are reviewed indicating that the release of pro-inflammatory mediators such as eicosanoids and interleukin-1 from keratinocytes provides a suitable in vitro parameter of irritancy. Based on this response an assay system has been established which may partially replace animal tests such as the Draize test.

Localization of prostaglandin H synthase isoenzymes in murine epidermal tumors: suppression of skin tumor promotion by inhibition of prostaglandin H synthase-2.

The growth factor- and phorbol ester-inducible prostaglandin H synthase (PGHS)-2 has been found to be constitutively overexpressed in epidermal tumors generated by the initiation-promotion protocol in murine skin, whereas the expression of PGHS-1 does not change under these conditions. In this paper we report the intra-tumor distribution of the aberrantly expressed PGHS-2 and the cancer chemopreventive activity of a specific PGHS-2 inhibitor. By immunohistochemical methods using isoenzyme-specific antibodies, we found that the PGHS-1 protein was expressed in keratinocytes and Langerhans cells dispersed throughout the epithelial part of papillomas and squamous cell carcinomas and in inflammatory infiltrates occasionally seen in these tumors.

Localization of prostaglandin-H synthase-1 and -2 in mouse skin: implications for cutaneous function.

Prostaglandin-H synthase (PGHS)-1 and -2 expression in mouse skin and in keratinocytes in culture was determined using immunohistochemistry and Western blot analysis. In normal skin PGHS-1 immunoreactivity was found in individual keratinocytes present in the interfollicular epidermis and the upper part of the hair follicle. PGHS-2 immunostaining was detected in very few individual basal cells of the interfollicular epidermis and of the hair follicle.

cDNA cloning of a 8-lipoxygenase and a novel epidermis-type lipoxygenase from phorbol ester-treated mouse skin.

Using a combination of PCR cloning and conventional screening procedures, we isolated from phorbol ester-treated mouse epidermis two full length cDNA clones encoding novel lipoxygenases. One of the cDNAs turned out to be identical to the recently cloned 8-lipoxygenase [Jisaka et al., J.

Optical spectroscopy of breast biopsies and human breast cancer xenografts in nude mice.

Rotavirus gastroenteritis is one of the main causes of acute diarrhea in young humans and animals worldwide. The colostrum-deprived, artificially-reared, neonatal pig has been extensively used in our laboratory as a model animal for studying an experimentally-induced rotaviral gastroenteritis. Details on procurement of newborn pigs, immunological characteristics and artificial rearing conditions of colostrum-deprived neonatal pigs as well as on rotavirus inoculation, clinical manifestations and evaluation of intestinal damage caused by rotavirus infection are described.

Regulation of protein kinase Cmu by basic peptides and heparin. Putative role of an acidic domain in the activation of the kinase.

Protein kinase Cmu is a novel member of the protein kinase C (PKC) family that differs from the other isoenzymes in structural and enzymatic properties. No substrate proteins of PKCmu have been identified as yet. Moreover, the regulation of PKCmu activity remains obscure, since a structural region corresponding to the pseudosubstrate domains of other PKC isoenzymes has not been found for PKCmu.

Symptoms in children of British and of Bangladeshi parents measured by the Rutter B2 Questionnaire.

Objectives: Bangladeshi children are less frequently referred to a child psychiatric clinic than their British peers. This study aimed to ascertain if teachers observed less psychological symptoms in Bangladeshi than British children.

Method: Teachers completed a Rutter B2 Scale on samples of 113 'Bangladeshi' and 61 British children aged between 5 and 11 years.

Differential expression of the regularly spliced wild-type p53 and its COOH-terminal alternatively spliced form during epidermal differentiation.

In the present study, we investigated the role of p53 in the differentiation of epidermal keratinocyte cells. The interrelationship between p53 expression and the various stages of epidermal differentiation and the role of the COOH terminus of the p53 molecule in this process were determined by comparing the expression of the regularly spliced p53 (RSp53) molecule and that of the COOH-terminal alternatively spliced (ASp53) form. p53 mRNA distribution was studied by in situ analysis of frozen skin sections and by reverse transcription-PCR analysis of the various wild-type p53 forms expressed in neonatal skin cell fractions separated by Percoll gradient.

Repetin (Rptn), a new member of the "fused gene" subgroup within the S100 gene family encoding a murine epidermal differentiation protein.

We report the cloning and characterization of a murine epidermal differentiation gene, repetin (Rptn), exhibiting striking similarity to the genes of the intermediate filament-associated proteins profilaggrin and trichohyalin. The repetin gene consists of three exons and two introns. The first exon is short and untranslated.

Suppression of apoptosis in COLO 205 cells by the phorbol ester TPA may be mediated by the PKC isoenzyme alpha.

Apoptosis induced by an antibody to CD95/APO-1/FAS in the colon carcinoma cells COLO 205 and HT-29 is suppressed by the phorbol ester TPA. Inhibition is much more effective in COLO 205 than in HT-29 cells. The TPA effect is abrogated by the protein kinase C (PKC)-specific inhibitor Go6983 indicating a role of PKC in this process.

Phosphorylation of protein kinase Cdelta (PKCdelta) at threonine 505 is not a prerequisite for enzymatic activity. Expression of rat PKCdelta and an alanine 505 mutant in bacteria in a functional form.

A structural feature shared by many protein kinases is the requirement for phosphorylation of threonine or tyrosine in the so-called activation loop for full enzyme activity. Previous studies by several groups have indicated that the isotypes alpha, betaI, and betaII of protein kinase C (PKC) are synthesized as inactive precursors and require phosphorylation by a putative "PKC kinase" for permissive activation. Expression of PKCalpha in bacteria resulted in a nonfunctional enzyme, apparently due to lack of this kinase.

Murine epidermal lipoxygenase (Aloxe) encodes a 12-lipoxygenase isoform.

Using a combination of conventional screening procedures and polymerase chain reaction cloning, we have isolated a cDNA encoding an epidermis-type 12-lipoxygenase (e12-lipoxygenase) from mouse epidermis. The open reading frame corresponds to a protein of 662 amino acids and was found to be 99.8% identical to the ORF of an epidermal lipoxygenase gene Aloxe, described recently [Van Dijk et al.

Relationship between TGF alpha-induced DNA synthesis and prostaglandin synthesis in human HaCaT keratinocytes.

The relationship between transforming growth factor alpha (TGF alpha)-induced cell proliferation and prostaglandin synthesis was investigated using growth-arrested human keratinocytes of the HaCaT line. Depending on the TGF alpha concentration, the stimulation of DNA synthesis (5-fold) was found to be either insensitive (at < 10 ng/ml TGF alpha) or sensitive (at > or = 20 ng/ml TGF alpha) to inhibition by both indomethacin, an inhibitor of prostaglandin synthases (PGHS) 1 and 2 and the PGHS 2-specific inhibitor NS-398. Indomethacin-effected inhibition did not correlate with cytotoxicity and was restricted to a narrow time window after growth factor administration.

Immunological demonstration of protein kinase C mu in murine tissues and various cell lines. Differential recognition of phosphorylated forms and lack of down-regulation upon 12-O-tetradecanoylphorphol-13-acetate treatment of cells.

13 murine tissues and 12 cell lines were tested for the expression of the novel protein kinase C (PKC) isoenzyme mu. Using two different PKC mu antibodies (sc-639 and P26720), PKC mu was detected in all tissues and cells and thus proved to be an ubiquitous PKC isotype. However, in some tissues, PKC mu was recognized only by the antibody P26720 and not by sc-639.

Expression of growth arrest-specific (Gas) genes in murine keratinocytes: Gas2 is specifically regulated.

In order to elucidate a possible role of growth arrest-specific (gas) genes in the regulation of tissue proliferation, we analyzed their expression in keratinocytes isolated from murine back skin. On the mRNA level gas1, gas5, and gas6 were found to be significantly expressed whereas there was a relatively low expression of gas2, gas3, and gas4. Using keratinocytes fractionated according to their density resulted in subpopulations of cells: differentiating suprabasal cells in fractions I and II; proliferative basal cells in fractions IIIa, III and IV.

Mechanisms in tumor promotion: guidance for risk assessment and cancer chemoprevention.

In mouse skin, tumor development promoted by 'non-genotoxic' carcinogens is closely related to the wound response. In both cases endogenous factors such as cytokines and eicosanoids released primarily from 'activated keratinocytes' play a key role as mediators of inflammation and cellular hyperproliferation. The liberation of interleukin-1 alpha and arachidonic acid from human keratinocytes has been used as an in vitro parameter of irritancy.