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Biomedical subjects

W L Epstein

Publications and source records attributed to W L Epstein.

At least 55 records · Page 3Linked to original sources
PubMed1989

Topical prevention of poison ivy/oak dermatitis.

An organoclay preparation was evaluated for topical protection against experimental poison ivy/oak in a rigorous double-blind study. By direct comparison with the same subject, it proved more effective than comparable preparations of bentonite, kaolin, or silicone in 16 of 17 trials. When evaluated globally against control responses to urushiol the organoclay preparation gave 95.3% protection against topical urushiol applications, ranging from 4.75 to 0.0475 nmol. Bentonite, kaolin, and silicone gave 29.6%, 37.9%, and 32.9% protection, respectively, in the same system. We conclude that organoclay is an effective topical protectant against experimental poison ivy/oak dermatitis, and deserves further clinical evaluation.

Administration, Cutaneous↗
PubMed1988

Soluble dipeptidyl peptidase IV from terminal differentiated rat epidermal cells: purification and its activity on synthetic and natural peptides.

In terminally differentiated epidermal cells dipeptidyl peptidase IV (EC 3.4.14.5) (DPP IV) is present mainly in a soluble form. We purified the enzyme from 2-day-old rat cornified cells to homogeneity by Sephadex G-200 and Mono-Q column chromatography and finally HPLC gel filtration on G3000SW. The enzyme was estimated to be Mr 190,000 by HPLC gel filtration and Mr 90,000 by sodium dodecyl sulfate-electrophoresis. The enzyme showed general properties reported for detergent-solubilized DPP IV from other tissues. It was Con A binding and almost completely inhibited by 1 mM diisopropyl fluorophosphate and Diprotin A. The pI was 5.6 and the pH optimum was 7.5. The specific activity for Gly-Pro-p-nitroanilide was 31.9 units/mg. HPLC analysis demonstrated the release of dipeptides of the N-terminal of substance P, beta-casomorphin, and their related peptides. A stoichiometric reaction of the enzyme on substance P was observed. The epidermal DPP IV had a Km of 0.3 mM and a kcat of 50.3 s-1 for substance P and the Km value decreased by shortening the peptide from the carboxyl-terminal amino acids. The enzyme hydrolyzed human and bovine beta-casomorphin with Km values of 0.025 and 0.05 mM, respectively. Shortening the bovine beta-casomorphin peptide chain did not affect enzyme affinity.

Animals↗
PubMed1988

Purification and characterization of bradykinin-hydrolyzing enzyme from 2-day-old rat epidermis.

Bradykinin-hydrolyzing enzyme was purified 200-fold from a soluble fraction of cornified cells from 2-day-old rat epidermis. The enzyme has an Mr of 80,000 as identified by SDS polyacrylamide gel electrophoresis and HPLC gel filtration. The isoelectric point of the enzyme is 5.05. The enzyme hydrolyzed Phe5-Ser6 of bradykinin and seven bradykinin-related peptides, and Tyr5-Ser6 of Tyr5-bradykinin. Production of bradykinin fragments, Arg-Pro-Pro-Gly-Phe and Ser-Pro-Phe-Arg, proceeded in a stoichiometric fashion. Km and Vmax values for bradykinin were 33 microM and 22.2 mumol/min per mg, respectively. The enzyme did not hydrolyze azocasein, denatured hemoglobin or synthetic substrates for other epidermal proteinases. The enzyme activity was enhanced by reducing agents and inhibited by sulfhydryl-blocking agents and divalent cations. Diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride had no effects. The enzyme has a pH optimum of 7.0-7.5 and is stable at 4 degrees C for 1 month, but loses activity completely at 60 degrees C for 10 min. The epidermal endopeptidase differs in several properties from endooligopeptidase A purified from brain which hydrolyzes Phe5-Ser6 of bradykinin.

Amino Acid Sequence↗
PubMed1988

Hydrolysis of histones by proteinases.

Hydrolysis of histones by proteinases from rat liver, skin and other sources was studied by using a rat thymus histone preparation as the substrate and polyacrylamide-gel electrophoresis and densitometric analysis as the methods to detect histone subtypes and their hydrolysis. The rat mast-cell proteinase I effectively hydrolysed histones except type H4. Thrombin hydrolysed effectively histones H1 and H2A, whereas plasmin hydrolysed all types of histones. Cathepsin D hydrolysed especially histone H2A. Cathepsins B and L hydrolysed all histones more slowly, and cathepsin H hydrolysed them extremely slowly. Epidermal aminoendopeptidase did not hydrolyse histones. Trypsin and chymotrypsin were used as reference enzymes, which hydrolysed all types of histones in very low concentrations. This study suggests that a variety of proteinases could play a role in histone hydrolysis. Hydrolysis of a specific subtype of histones, such as histone H2A at pH 6 by cathepsin D, may be directly involved in regulation of epidermal-cell differentiation.

Aminopeptidases↗
PubMed1988

Biopsy method for human adipose with vitamin E and lipid measurements.

An adaptation of the needle biopsy procedure of Beynen and Katan for human adipose tissue, which yields 2-10 mg adipose samples, is described and evaluated. Micromethods are presented for the analysis of alpha-tocopherol, cholesterol and fatty acids in each adipose specimen. The needle biopsy procedure, which uses a Vacutainer to create suction, is compared with a punch biopsy method. The needle biopsy is rapid (6 samples/hr), simple and unobjectionable to the subjects, and provides samples with reproducible ratios of cholesterol and alpha-tocopherol. Unlike the punch biopsy, the needle biopsy reliably obtains specimens with a lipid composition typical of adipocytes. The needle biopsy method is adaptable to nutritional studies of tocopherol and fatty acid metabolism in adipose, and to studies of hazardous compounds stored in adipose. The linoleic acid content of adipose from residents of the West Coast was found to be considerably higher than values reported earlier. The adipose fatty acid data indicate an increase in human adipose linoleate when compared with earlier reports and suggest a trend toward increasing linoleic acid in the American diet.

Adipose Tissue↗
PubMed1988

Skin granuloma formation in mice immunosuppressed by cyclosporine.

Granulomatous tissue reactions appear in athymic mouse skin, indicating that initiation of granuloma formation may be T-cell independent. To further evaluate the relationships between granuloma formation and T-cell function, we treated euthymic BALB/c mice with cyclosporine (Cs), a potent immunosuppressive drug, injected intramuscularly (150 mg/kg/day) 5 times a week. Hepatic granulomas were isolated from mice with schistosomiasis and transplanted into the skin of mice treated with Cs for 2 weeks. Cyclosporine injection was continued for 3 additional weeks. Blood levels of the drug increased during treatment (489 ng/ml at 2 weeks and 822 ng/ml at 5 weeks). Morphologically identical granulomas developed in both treated and untreated mice. Examination for T-cell functions showed that by the end of 2 weeks treatment, concanavalin A, phytohemagglutinin responses, and IL-2 activity were markedly depressed, and IL-2 receptor expression was not detected in either lymph nodes or spleen of the Cs-treated mice; however, after hepatic granuloma graft, T-cell functions in regional lymph nodes, but not in spleen, as well as peripheral blood eosinophilia were stimulated in Cs-treated mice. These data strongly suggest that intact T-cell activity is not essential for the initiation of granuloma formation. In addition, granuloma grafts appear to stimulate Cs-resistant T-cell activation locally, which amplifies and organizes the granulomatous response.

Animals↗
PubMed1988

Limited proteolysis of high molecular weight histidine-rich protein of rat epidermis by epidermal proteinases.

Epidermal proteinases, which may be involved in proteolysis of Mr greater than 300k histidine-rich protein in epidermis, were studied by SDS-PAGE analysis. Mr greater than 300k histidine-rich protein was extracted from granular cells of 2-day-old rats in citric acid-sucrose solution and separated from proteinases and smaller Mr proteins by Sephacryl S-300 column chromatography. The proteinase-free histidine-rich protein was stable in pH 3.5-9 at 37 degrees C for 12 h. Proteinases were partially purified from rat epidermis and inhibitor spectrum determined for each enzyme. Limited hydrolysis of Mr greater than 300k histidine-rich protein yielded a derivative of Mr 56k with cathepsin D at pH 3.5-7.5 and a serine proteinase at pH 7-9. Further proteolysis of Mr 56k protein to Mr 44k and a doublet of Mr 45k and 47k also was detected with cathepsin D at pH 3.5 and 7.5, respectively, while the serine proteinase degraded Mr 56k protein to a number of protein bands. Cathepsins B and L degraded Mr greater than 300k protein but no specific predominant product was identified. We suggest that cathepsin D and the serine proteinase may play a role in in situ processing of histidine-rich protein during cornification.

Animals↗
PubMed1988

T-cell depletion by monoclonal antibodies does not prevent granuloma formation in mice.

Effects of T-cell depletion on the formation of organized granulomas in mouse skin were investigated. Monoclonal antibodies (MoAbs) to L3T4 and Lyt-2.2 were injected into euthymic BALB/c mice in order to deplete both T-helper and T-suppressor cell populations. Four days after injection, hepatic schistosome egg granulomas were transplanted into the skin. Injection of MoAbs to L3T4 and Lyt-2.2 was repeated in the recipient mice 6 days later. At the time of transplantation, flow cytometric analysis showed that the number of T cells which were positively stained with surface markers decreased on average by 68% in both regional lymph nodes and spleen. The mitogen response of spleen cells was also markedly reduced. Despite their immunosuppressed condition, development of organized granulomas was observed in the skin of recipient mice by light and electron microscopy 3 weeks after transplantation. The findings indicate that T-cell function may not be essential for initiation of organized granuloma formation.

Animals↗
PubMed1987

Purification and some properties of bound cysteine proteinase inhibitor from cornified cells of newborn rat epidermis.

Cysteine proteinase inhibitor exists in two forms in terminally differentiated keratinocytes. One is readily soluble in 20 mM sodium phosphate buffer but the other is bound to the plasma membrane and is poorly soluble. The cysteine proteinase inhibitor (CPI) from the membrane was extracted from cornified epidermal layers of 2-day-old rats and its properties were compared with those of soluble CPI. This CPI (bound CPI) was solubilized in alkaline 8 M urea containing 2-mercaptoethanol from the residual tissue exhaustively treated with buffered 4 M urea. CPI was separated from keratin by ammonium sulfate precipitation and purified by means of papain affinity chromatography, ion exchange column chromatography and gel filtration. Bound CPI had an Mr value of about 16,000, a pI value of 3.8 and was unstable at above 80 degrees C, while soluble CPI was of Mr 13,000 and stable at above 80 degrees C. Both CPIs were stable at 4 degrees C in the range of 3.0-9.0. Bound CPI contained half cystine and the ratio of acidic-to-basic amino acids was 3.18. Bound CPI inhibited rat liver cathepsins B, H, and L but did not inhibit the activity of noncysteine proteinases. Papain activity was inhibited by bound CPI at three sites, noncompetitively, and the Ki value was calculated to be 0.11 nM.

Animals↗
PubMed1987

Induction of granuloma-dependent angiotensin-converting enzyme and eosinophil chemotactic factor in the skin of athymic nude mice.

Activities of angiotensin-converting enzyme (ACE), other proteinases, and eosinophil chemotactic factor (ECF-G) are known to be elevated in hepatic hypersensitivity granulomas of thymus intact (nu/+) mice after Schistosoma mansoni infection. The enzyme activities also increase, but to a lesser degree in hepatic granulomas of athymic nude (nu/nu) mice, and ECF-G is not detectable. In this study isolated hepatic granulomas from nu/+ mice were grafted into the skin of uninfected nu/nu mice, and changes in those cellular functions were determined to examine whether the newly formed granulomas by recipient nu/nu cells acquire the functional activities as well as the histological appearance of nu/+ granulomas. ACE and ECF-G rapidly disappeared from grafted sites during the first 5 days, corresponding to loss of nu/+ cells from the graft. Reduction in activities of arylsulfatases, lysozyme, and acid phosphatase also occurred, but to a lesser extent. Recovery of ACE and ECF-G activities to the levels seen in nu/+ hepatic granulomas was observed by 14 days after grafting when nu/nu cells had accumulated in the grafts and formed new granulomas. Other enzymes increased to approximately half the levels seen in grafted donor granulomas. Circulating eosinophilia also increased. The findings indicate that nu/nu cells that accumulated in the skin grafts not only morphologically mimicked nu/+ type granulomas but also demonstrated nu/+ levels of cellular function. Analysis of skin granulomas developing in nu/+ mice after grafting of nu/+ hepatic granulomas showed the similar histology and enzymatic changes, whereas the skin sites inoculated with purified schistosome eggs alone caused neither significant histological changes nor elevation of ACE activity.

Acid Phosphatase↗
PubMed1987

The highly modified membrane of cornified cells in stratified squamous epithelia: a comparison of heterogeneous deposits in keratinized and nonkeratinized epithelia.

The chemical nature of the thickened plasma membrane of cornified cells in stratified squamous epithelium was investigated in comparison with that in noncornified epithelium. Localizations of transglutaminase, molecular weight 92,000 daltons, and detection of epidermal cysteine proteinase inhibitor were effected with a monoclonal antibody and a monospecific rabbit anti-inhibitor immunoglobulin, respectively, directed to the antigens. N-(7-dimethylamino-4-methylcoumarinyl)maleimide was used to demonstrate S-S cross-linking. In all keratinizing epithelia, the enzyme and inhibitor were deposited on membranes of granular cells. S-S bonds were formed in cornification with the appearance of electron-dense material by the inner leaflet. Both enzyme and inhibitors occurred on the corneal epithelium, but S-S linkage and the thickened plasma membrane did not form even at the last stage of maturation. On the other hand, the internal vaginal epithelium in the proestrous stage without keratinization contained the enzyme, but neither inhibitor nor S-S linkage. Both antigens and S-S bonds were detected when keratinization proceeded during estrus. The staining patterns in the epithelium near the vaginal introitus were identical to those in the skin. Cuboidal and simple epithelia exhibited none of those constituents. The findings indicated that heterogeneous components contribute to modification of the plasma membrane of cornified cells, but S-S cross-linkages are associated exclusively with formation of the ultrastructurally unique membrane structure. In addition, findings suggested hormonal regulation in the chemical modification of the membrane in estrogen-sensitive internal vaginal epithelium.

Animals↗
PubMed1987

Plant-induced dermatitis.

Patients with plant-induced dermatitis frequently present to the emergency department. The range of responses varies from irritant to allergic to photo or granulomatous. To a certain extent the clinical presentations will vary; it is important to determine causation because appropriate emergency therapy treatment also will vary. This review considers the most common forms of plant dermatitis and emphasizes advances in the understanding of pathomechanisms and recommended therapy for each type.

Dermatitis, Atopic↗
PubMed1987

Separation and identification of cathepsins in newborn rat epidermis.

Cathepsins B, D, H, and L were identified in the extract of 2-day-old rat epidermis and separated by gel filtration from aminoendopeptidase with a Mr of 400,000 and from the low-molecular-weight cysteine proteinase inhibitor. They were further purified by ion exchange column chromatography. The final separation for cathepsins B and H was performed by gel filtration, while cathepsin D was purified by pepstatin affinity chromatography and cathepsin L by fast protein liquid chromatography (FPLC). Substrate specificity, inhibitor susceptibility, and apparent molecular weights of the separated proteinases were determined and values compared to rat liver enzymes. Apparent molecular weights for epidermal cathepsins B, H, and L were higher than those for comparable liver enzymes of adult rats. The cysteine proteinase inhibitor in epidermis was found to inhibit cathepsins B, H, and L but not cathepsin D and aminoendopeptidase of rat epidermis. This study demonstrates the presence of cathepsin L in the epidermis and describes simultaneous separation and comparison of epidermal catheptic proteinases.

Animals↗
PubMed1987

Granulomatous slack skin: clonal rearrangement of the T-cell receptor beta gene is evidence for the lymphoproliferative nature of a cutaneous elastolytic disorder.

Granulomatous slack skin (GSS) is characterized by the slow evolution of bulky, erythematous skin folds that have a granulomatous histology, and show destruction of dermal elastic tissue. Several cases have been putatively associated with Hodgkin's disease, and histologic similarities to mycosis fungoides have also been noted. We examined tissue from 3 cases of GSS to determine whether the condition was inflammatory or lymphoproliferative in nature. We found an abnormal, monomorphous T-helper cell immunophenotype, and in all 3 cases, clonal rearrangement of the T-cell receptor beta gene. We conclude that GSS is an indolent cutaneous T-cell lymphoma associated with granulomatous inflammation that mediates elastolysis, producing a distinctive clinical appearance.

Female↗
PubMed1987

Transfer of granulomatous inflammation with nonviable preparations of schistosome granulomas in naive mice.

Hepatic granulomas of euthymic (nu/+) mice infected with Schistosoma mansoni were freeze-dried or freeze-thawed 3 times and transplanted subcutaneously into naive nu/+ and athymic (nu/nu) mice. The grafted sites, studied histologically, showed formation of organized granulomas in nu/+ mice similar to donor granulomas as observed after grafting of freshly isolated granulomas. On the other hand, in nu/nu mice, the nonviable transplants elicited small and disorganized granulomas, like hepatic granulomas in nu/nu mice with schistosomiasis, but different from fresh nu/+ transplants in nu/nu skin. The findings indicate viable cells are not required for transfer of granulomatous reactions, but T cells are needed for full expression.

Animals↗
PubMed1987

Oral hyposensitization to poison ivy and poison oak.

We evaluated the safety and efficacy of a 1:1 mixture of pentadecylcatechol (PDC) and heptadecylcatechol (HDC) diacetate in reducing hypersensitivity to poison ivy and poison oak. The study was double-blind, parallel, randomized, and placebo controlled. The 44 subjects receiving the active drug ingested a cumulative dose of 306.5 mg over a five-week period. Subsequently, 14 patients were continued on a maintenance phase, ingesting an additional 960 mg of drug. The PDC-HDC diacetate was well tolerated, with no significant side effects. Evaluation of efficacy compared poststudy and prestudy reactions to patch tests using urushiol in doses of 0.025, 0.05, 0.125, 0.25, and 0.5 micrograms applied to the forearm. The results indicated that the induction phase as well as the maintenance phase did not induce a statistically significant hyposensitivity to urushiol, and we were thus unable to decrease sensitivity to poison ivy and poison oak in humans using orally ingested PDC-HDC diacetate.

Administration, Oral↗