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Biomedical subjects

W L Epstein

Publications and source records attributed to W L Epstein.

At least 109 records · Page 6Linked to original sources
PubMed1982

Biochemical properties of thiol proteinase inhibitor purified from psoriatic scales.

Epidermal thiol proteinase inhibitor (EPI) was extracted from normal and psoriatic cornified cells with 10 mM Tris-HCl, pH 8.0, and purified by papain-Sepharose affinity chromatography and gel filtration. Both EPIs showed a single band and the same mobility in gel electrophoresis with and without sodium dodecyl sulfate. Their immunological identity also was seen by agar diffusion. The inhibitor activity of EPIs to papain and rat liver lysosomal enzymes which caused a local inflammatory reaction after intradermal injection was determined on alpha-N-benzoyl-DL-arginine-2-naphthylamide and azocasein. Their activities to papain were the same at pH 8.0, but EPI of psoriasis showed only 50% of the activity of normal cells at pH 5.0 and 6.0. EPI of normal cells was heat stable, while that of psoriasis was reduced in activity after heating at 90 degrees C. Inhibitor activity of EPI from psoriatic cells toward the lysosomal enzymes, cathepsin B and/or cathepsin H and cathepsin L, was also inferior to EPI from normal cells at all pHs studied. We suggest the possibility that the inflammatory response associated with psoriasis seems in part to result from epidermal cells producing a less effective EPI, which may be a natural anti-inflammatory substance.

Animals↗
PubMed1982

Partial purification and characterization of angiotensin-converting enzyme in mouse and human skin.

The chemical properties of skin angiotensin-converting enzyme were characterized in mouse and human. In newborn mice, dermis contained almost all activity (1.3 mU/mg), of which 30% was in the 22,000 kappa g supernatant and 70% in the pellet which could be solubilized by Triton X-100. The activity increased sharply during the first 6 weeks after the birth. By gel filtration, the enzyme in the supernatant was Mr 330,000, but the solubilized enzyme was Mr 430,000 in the presence of Triton X-100. By electrophoresis, the 2 enzyme fractions demonstrated a charge difference. The enzymes showed the same pH optima of around 8.1 and 7.7, and Km values of 2.6 and 0.11 mm for Hip-His-Leu and angiotensin I, respectively. Sensitivity to known inhibitors and heat stability of the enzymes in 2 fractions were similar. In the human, 56% of the activity in skin homogenates (1.5 mU/mg) appeared in this supernatant and 44% in the pellet. Both soluble and solubilized preparations showed enzyme activity with 2 different molecular weights, 330,000 and 430,000. The human enzymes had chemical properties similar to the mouse enzymes, but their affinity for Hip-His-Leu and angiotensin I were 1.6 and 2 times higher than those of the mouse enzymes.

Aging↗
PubMed1982

Induction of antigen specific hyposensitization to poison oak in sensitized adults.

Twenty-one adults, highly sensitive to urushiol, the allergen in poison oak/ivy, ingested up to 300 mg of urushiol over three to six months. A control group received placebo capsules. The study was done double blind to evaluate changes in patch test reactivity to urushiol, altered reactivity to an unrelated contract sensitizer, side effects, and duration of hyposensitization. A significant number of subjects in the experimental group (15/21) became hyposensitized. Such hyposensitization was not seen in the control group (2/12), and the difference between groups was significant. No change in reactivity to an unrelated contact sensitizer occurred in subjects hyposensitized to urushiol, suggesting antigen specificity. Retesting up to three months after completion of the protocol indicated that subjects remained hyposensitized without a "rebound" effect during the time. Side effects, detected by questionnaire, were limited to vesicular and urticarial rashes and pruritus ani in 18 of 21 test subjects.

Adult↗
PubMed1982

Tissue angiotensin-converting enzyme and lysosomal enzyme levels in skin diseases.

The activities of tissue angiotensin-converting enzyme (ACE) were investigated in several skin diseases. Biopsy specimens were taken from 49 patients with granulomatous lesions, including sarcoidosis, 16 patients with nongranulomatous lesions, and 13 normal individuals. The ACE level was measured fluorometrically and the lysosomal enzyme levels were measured by established techniques. It was found that ACE activity increased in all granulomatous skin lesions, but not in other inflammatory lesions. The enzyme activity showed an increase that paralleled the time course of the disease. In contrast, lysosomal enzymes increased in various types of skin lesions, suggesting that they reflect nonspecific inflammation. These findings indicate that the tissue ACE level may be a marker for granulomatous inflammation, but one that is not specific for sarcoidosis.

Acid Phosphatase↗
PubMed1981

Studies of heterogeneity of angiotensin-converting enzyme and acid phosphatase in granulomatous lesions of skin.

Activities of angiotensin-converting enzyme and acid phosphatase were markedly elevated in the lesions of metal-induced hypersensitivity and foreign body types of granulomas. We biochemically studied these enzymes by means of gel filtration and electrophoresis and compared them with the same enzymes of normal dermis. Two forms of angiotensin-converting enzyme found in normal dermis were increased proportionally. Catalytic properties and heat stability of the enzyme in the lesions and normal dermis were the same. On the other hand, acid phosphatase in the lesions showed a different isozyme pattern from that seen in normal dermis. The enzyme from normal dermis had apparent molecular weight of 150000 and 90000, whereas an additional enzyme with a molecular weight of 230000 was detected in granulomatous lesions. Three isozymes were demonstrable in normal dermis but two additional isoenzymes appeared in granulomatous lesions: the isozyme patterns between the foreign body and hypersensitivity granulomas are different.

Acid Phosphatase↗
PubMed1981

Induction of persistent tolerance to urushiol in humans.

Young nonimmune subjects were injected intramuscularly multiple times with small amounts of urushiol oil derived from poison oak. One week after the last injection this group and another group of age-matched controls were exposed to a sensitizing dose of the oil painted on the skin. All were challenged at 1 mo, then each year for 7 yr. Initially all experimental subjects were tolerant to high challenge doses; this persisted for 1 yr, at which time experimental subjects were no longer completely tolerant but were clinically tolerant (hyporeactive). This state persisted for at least 4 yr, and this represents complete tolerance followed by long-lasting hyposensitization.

Adolescent↗
PubMed1981

Effects of hyaluronidase and neuraminidase on immunoreactivity histidine-rich protein in newborn rat epidermis.

Frozen sections of newborn rat skin were treated with a variety of buffers, enzymes, and proteinase inhibitors in order to modify the reactivity of antigenic sites of histidine-rich protein and keratin. By indirect immunofluorescence, we found that antiserum to histidine-rich protein purified from granular cells reacted with keratohyalin granules but not cornified cells treated with hyaluronidase. The same antiserum reacted less distinctly with keratohyalin granules treated with neuraminidase; in contrast, it showed strong reactivity in cornified cells after the neuraminidase digestion. However, the enzyme digestions did not unmask the antigenic site(s) of keratohyalin granules to anti-keratin serum, as did saline in 0.1 M Tris-HCl buffer, pH 8.0. These results suggest that the antigenic site of histidine-rich protein is masked in keratohyalin granules by different mechanisms from the masking of keratin. Histindine-rich protein may be masked primarily with hyaluronic acid in keratohyalin granules, but the sugar moiety appears to be changed to sialic acid in cornified cells.

Animals↗
PubMed1981

Effects of glutaraldehyde and osmium tetroxide on newborn rat epidermal keratin.

The effects of glutaraldehyde and osmium tetroxide (OsO4) fixation on ultrastructural and biochemical changes of epidermal keratin were investigated. Morphometrically, the apparent size of keratohyalin granules was smallest when granular cells were fixed with OsO4, whereas those fixed with glutaraldehyde were larger, and those double-fixed with glutaraldehyde and OsO4 were largest. The ultrastructure of tonofilaments appeared different in each type of fixation. Biochemically, cross-linking glutaraldehyde with purified keratin from cornified cells formed a high molecular weight product with a blue shift of the absorption maximum and an increase in absorbance. Detection of the absorption spectra of OsO4- keratin reactions revealed that a new absorption maximum around 410 nm developed in glutaraldehyde-treated keratin, while one around 315 nm appeared in nontreated keratin. In addition, glutaraldehyde pretreatment increased by 40% the initial reaction rate and by 23% the total amount of OsO4 reduction. Sodium dodecyl sulfate gel electrophoresis demonstrated that degradation of keratin molecules occurred in both glutaraldehyde-treated and untreated keratin after 2 hr of exposure to OsO4. These findings indicate that keratin molecules are chemically modified by fixatives routinely used for electron microscopy. We consider that this chemical information plays an essential role in the appropriate interpretation of the ultrastructure of epidermal cells.

Aldehydes↗
PubMed1980

Chemical characterization, synthesis and distribution of proteinase inhibitor in newborn rat epidermis.

A protein solubilized in Tris-HCl/saline buffer from keratinized cells of newborn rat epidermis exhibited inhibitor activity to papain and ficin, but not to trypsin, cathepsin D and pepsin. This protein was purified from keratinized cells as well as nonkeratinized and germinative cells by means of IgG affinity chromatography. The inhibitors extracted from all cell layers were immunologically identical and had a molecular weight of approximately 12,500 +/- 500. Since amino acid analysis showed that the inhibitor contains about 35 residues of glycine per mol, [3H]glycine was used to investigate synthesis of the protein. The inhibitor from nonkeratinized and germinative cells was radioactively labeled by 2 h after injection and appeared in keratinized cells by 48 h after injection. Indirect immunofluorescence microscopy demonstrated in situ distribution of the protein in the entire epidermis, and the protein localized by the plasma membrane in granular cells and diffusely in keratinized cells was shown to be insoluble in Tris-HCl saline buffer. The results indicate that a thiol-proteinase inhibitor is synthesized in epidermal cells during keratinization and is retained as part of the cytoplasmic structure

Amino Acids↗
PubMed1980

Light-scattering studies of cation-stimulated filament assembly of newborn rat epidermal keratin.

Effects of CaCl2 on in vitro polymerization of keratin extracted from cornified cells of newborn rat were investigated by means of light-scattering and supramolecular structures. Elongation and parallel assembly of filaments occurred with addition of CaCl2 to dialyzed keratin solutions and was detected by an increase in light-scattering intensity. Nonfibrous aggregates which occurred in higher buffer concentrations and in lower pH were also recorded as intensity increased. MgCl2, ZnCl2, and GdCl3 demonstrated similar effects, but NaCl and KCl showed no effect.

Animals↗
PubMed1980

Sesquiterpene lactone dermatitis. Cross-sensitivity in costus-sensitized patients.

Thirteen costus-sensitive patients were patch tested with 38 sesquiterpene lactones of five different classes over a two-year period. Cross-reacting agents fell into two chemical categories: (1) those that resembled the primary sensitizer, and (2) those belonging to different skeletal classes. An exocyclic methylene group conjugated to a gamma-lactone was present in both chemicals that cross-reacted and those that did not. The difference between these two groups is that cross-reacting chemicals are not highly substituted, tending to be lipophilic, while those giving negative responses all are highly substituted at the C-8/C-6 position. This functional group may hinder binding of exocyclic methylene with skin protein or the actual antigenic site with an immune receptor cell.

Cross Reactions↗