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Biomedical subjects

B U Wintroub

Publications and source records attributed to B U Wintroub.

At least 19 recordsLinked to original sources
PubMed2007

A systematic review of the safety of topical therapies for atopic dermatitis.

BACKGROUND: The safety of topical therapies for atopic dermatitis (AD), a common and morbid disease, has recently been the focus of increased scrutiny, adding confusion as how best to manage these patients. OBJECTIVES: The objective of these systematic reviews was to determine the safety of topical therapies for AD. METHODS: Databases searched included: OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, and the Cochrane Central Register of Controlled Trials. In addition to the articles identified by this search, investigators were also referred to a list of links (most recently updated 25 September 2005) to recent Food and Drug Administration (FDA) studies, reports and meetings regarding the topical calcineurin inhibitors for further potential references. Only fully published papers available in English and data obtained from FDA sites were included. Furthermore, the criteria for inclusion and exclusion for each systematic review were further evaluated at a meeting of all of the content and evidence-based medicine experts participating in this process and alteration of the inclusion criteria was done at that time when it was felt necessary to avoid inclusion of lower-quality data in the review. Qualitative review of the abstracted data was performed and reviewed at a meeting of all of the content and evidence-based medicine experts. RESULTS: While systemic exposure to these topical agents does occur, physiological changes appear to be uncommon and systemic complications rare and have only been found with use of topical corticosteroids. CONCLUSIONS: Based on the data that are available the overall safety of AD therapies appears to be good with the only documented systemic side-effects of therapy those occasionally seen with use of topical corticosteroids.

Administration, Topical↗
PubMed1996

The impact of managed care on graduate medical education and academic medical centers.

The goal of this article is to examine the present and future impact of managed care on graduate medical education (GME) and academic medical centers. Obviously, the later 2 entities are closely intertwined and will share in the consequences of changes in our medical care systems. However, there are differences in the funding of medical schools as compared with GME provided by teaching hospitals, and an appreciation of the vital issues and concerns requires that each be discussed separately.

Academic Medical Centers↗
PubMed1992

Human skin mast cell carboxypeptidase: functional characterization, cDNA cloning, and genealogy.

We functionally characterized human skin mast cell carboxypeptidase A (MC-CPA), and explored its evolutionary relationship to other carboxypeptidases to understand further the structural basis for the substrate preferences of this enzyme. Purified human skin MC-CPA displayed more activity than did bovine pancreatic carboxypeptidase A (CPA) against carboxyl-terminal leucine residues, about equal activity with phenylalanine and tyrosine residues, and no activity with tryptophan or alanine. To correlate kinetic data with structure, we isolated and sequenced a cDNA encoding MC-CPA from human skin, and directly sequenced 30% of the purified protein. These sequences agreed with that of human lung MC-CPA, and further support the evidence for a single MC-CPA gene in humans. Four amino acid replacements, resulting in a net positive change in non-hydrogen atoms in the S1' subsite of MC-CPA, were associated with less alteration in substrate specificity, relative to bovine CPA, than might be expected from studies using rat CPA1 and CPA2. We noted two consensus N-linked glycosylation sites in human MC-CPA that are not found in rat and mouse MC-CPA, or in bovine CPA; that at least one of these sites is glycosylated in vivo was verified by N-glycosidase F treatment, lentil lectin binding, and Concanavalin A-Sepharose chromatography. Evolutionary trees constructed from the known carboxypeptidase sequences suggested that MC-CPA most likely evolved from a carboxypeptidase B-like enzyme, independent of the pancreatic CPA. Thus, in the carboxypeptidase gene family, MC-CPA displays a unique genealogy and several amino acid replacements in its S1' binding pocket that result in substrate specificity quite similar to bovine CPA.

Amino Acid Sequence↗
PubMed1991

Human mast cell carboxypeptidase. Selective localization to MCTC cells.

Two murine mAb were prepared against human mast cell carboxypeptidase (HMC-CP) purified from human skin, and were termed CP1 and CP2, respectively. Double immunohistochemical labeling of Carnoy's-fixed sections of human skin, lung, and gastrointestinal tissue with CP1 and CP2, respectively, and with a murine monoclonal antitryptase antibody demonstrated that HMC-CP was selectively present in a subset of human mast cells. Double labeling experiments with CP1 and CP2, respectively, and a murine anti-chymase mAb demonstrated the presence of HMC-CP in the tryptase-positive, chymase-positive mast cell type (MCTC) only. Immunohistochemical labeling of peripheral blood leukocytes resulted in staining of monocytes with CP2 but not with CP1. In addition to chymase and a cathepsin-G like proteinase, HMC-CP is another neutral protease that is selectively present in the MCTC tryptase-positive, chymase-positive mast cells type of mast cell, thus extending the biochemical definition of human mast cell heterogeneity.

Antibodies, Monoclonal↗
PubMed1990

Serial subculture and relative transport of human endothelial cells in serum-free, defined conditions.

Endothelial cells bind, process, and transport bioactive molecules and thus provide an interactive interface between the plasma and adjacent tissues. Various hormones and factors induce endothelial cells to synthesize and secrete interactive factors. However, study of endothelial cell synthesis, processing, and transport of these bioactive molecules has been impeded because of the serum requirement for cell growth. Many of these bioactive molecules are derived from or are modified by serum components. We have developed a short-term culture system that supports sequential subculturing of endothelial cells in a serum-free culture medium on a defined extracellular matrix. The cells have a doubling rate of 33 h and the total cell number can be expanded more than 800-fold. Expression of specific markers; factor VIII related antigen-von Willebrand factor, Wiebel-Palade bodies, a cobblestone appearance of confluent cell monolayers, and angiotensin-converting enzyme activity confirm the normal morphologic integrity and biochemical function of these cultures. Using this defined serum-free medium, we have grown human endothelial cell monolayers on porous polycarbonate membrane inserts, thereby creating an upper and a lower chamber that models the vascular architecture and demonstrates an inverse relationship between transport and molecular weight. By eliminating serum components, this model system should facilitate the study of endothelial cell binding, metabolism, and transport of bioactive molecules and may contribute to a better understanding of the blood-tissue interface.

Angiotensin II↗
PubMed1989

Erythropoietin binding and induced differentiation of Rauscher erythroleukemia cell line red 5-1.5.

We isolated from the Rauscher erythroleukemia cell line (Red 5), a subclone (Red 5-1.5), which contains erythropoietin (epo) binding sites and demonstrates an epo-dependent erythroid differentiation. One class of high affinity binding sites was detected with a Kd (+/- S.D.) of 0.43 +/- 0.09 nM and a mean density/cell of 1200 +/- 311. The cell-associated 125I-epo was displaced by nonlabeled epo but not by other hormones or factors. The 125I-epo binding to Red 5-1.5 cells was maximal within 3 h at 15 degrees C and 1 h at 37 degrees C and proportional to cell number. The addition of epo increased [3H] uridine incorporation into RNA by 6 h and [3H]thymidine incorporation into DNA by 60 h followed by 59Fe incorporation into protein, cell proliferation, and formation of hemoglobin-containing colonies. The incorporation of 59Fe into protein demonstrated a linear dose response (from 0.002 to 1.5 units of epo/ml) beginning 60 h after addition of the hormone to the cultures, and there was a dose-dependent increase (from 0.1 to 1.0 unit of epo/ml) in the formation of hemoglobin-containing colonies. We concluded that the binding of 125I-epo to Red 5-1.5 suggests the presence of specific epo receptors. The sequence of the epo-induced proliferation and differentiation events is similar to primary erythroid cultures but requires longer epo exposure. Receptor occupancy correlates with the induced biological response.

Animals↗
PubMed1989

Combined total body X-ray irradiation and total skin electron beam radiotherapy with an improved technique for mycosis fungoides.

Twelve consecutive patients with advanced stage mycosis fungoides (MF) were treated with combined total body X ray irradiation (TBI) and total skin electron beam radiotherapy (EBRT). Six had generalized plaque disease and dermatopathic nodes, three had tumor stage disease and node biopsy positive for mycosis fungoides, and three had erythroderma/Sezary syndrome. The treatment regimen consisted of split course total body X ray irradiation, given in twice weekly 15 cGy fractions to 75 cGy, then total skin electron beam radiation therapy given in once weekly 400 cGy fractions to a total dose of 2400 cGy. Underdosed areas and areas of greatest initial involvement were boosted 400 cGy twice weekly for an additional 1200 cGy. This was followed by a second course of total body X ray irradiation, to a total dose of 150 cGy. The total skin electron beam radiotherapy technique is a modification of an established six position EBRT technique for mycosis fungoides. Measurements to characterize the beam with and without a lexan scattering plate, demonstrated that the combination of no-plate beams produced better dose uniformity with a much higher dose rate. This improved technique is particularly advantageous for elderly and/or frail patients. Nine (75%) of the 12 patients achieved complete response (CR). The other three had significant improvement with greater than 80% clearing of their disease and resolution of symptoms. All six patients with generalized plaque disease achieved complete response and remained free of disease from 2 to 16 months. Two of three node positive patients also achieved complete response; one, with massive biopsy-documented mycosis fungoides nodal disease and deep open tumors, remained relapse-free over 2 years. Only one of the three patients with erythroderma/Sezary syndrome achieved a complete response, which was short lived. Therapy was well tolerated. No significant hematological toxicity occurred. Although total body X ray irradiation and total skin electron beam radiotherapy produced excellent palliation of patients with advanced stage mycosis fungoides, new strategies to provide more effective systemic treatment are needed.

Adult↗
PubMed1989

In vitro pemphigus vulgaris model using organotypic cultures of human epidermal keratinocytes.

Using the Combi-ring-dish (CRD), a new culture device, organotypic cultures of human epidermal keratinocytes were grown on bovine eye lens capsules. In these highly differentiated cultures, typical suprabasal acantholysis was induced by pemphigus vulgaris antibodies. This in vitro pemphigus vulgaris model may be used to analyse keratinocyte-derived factors causing acantholysis in experimental pemphigus.

Acantholysis↗
PubMed1989

Human mast cell carboxypeptidase. Purification and characterization.

A carboxypeptidase activity was recently identified in highly purified human lung mast cells and dispersed mast cells from skin. Using affinity chromatography with potato-tuber carboxypeptidase inhibitor as ligand, mast cell carboxypeptidase was purified to homogeneity from whole skin extracts. The purified enzyme yielded a single staining band of approximately 34,500 D on SDS-PAGE. Carboxypeptidase enzyme content estimated by determination of specific activity, was 0.5, 5, and 16 micrograms/10(6) mast cells from neonatal foreskin, adult facial skin, and adult foreskin, respectively. Human mast cell carboxypeptidase resembled bovine carboxypeptidase A with respect to hydrolysis of synthetic dipeptides and angiotensin I, but was distinguished from carboxypeptidase A in its inability to hydrolyze des-Arg9 bradykinin. The amino acid composition of human mast cell carboxypeptidase was similar to the composition of rat mast cell carboxypeptidase. The amino-terminal amino acid sequence of mast cell carboxypeptidase demonstrated 65% positional identity with human pancreatic carboxypeptidase B, but only 19% with human carboxypeptidase A. Thus, human mast cell carboxypeptidase is a novel member of the protein family of zinc-containing carboxypeptidases, in that it is functionally similar but not identical to bovine carboxypeptidase A, but has structural similarity to bovine and human pancreatic carboxypeptidase B.

Adult↗
PubMed1987

Detection and partial characterization of a human mast cell carboxypeptidase.

Using a high performance liquid chromatography assay that detects the cleavage of the C-terminal leucine from angiotensin I, we have identified a carboxypeptidase activity in mast cells from human lung and in dispersed mast cell preparations from human skin. The enzyme activity was detected in a preparation of dispersed human mast cells from lung of greater than 99% purity and was released with histamine after stimulation with goat anti-human IgE. In nine preparations of dispersed human mast cells from lung of 10 to 99% purity, net percentage of release of carboxypeptidase correlated with the release of histamine, localizing carboxypeptidase to mast cell secretory granules. The enzyme activity was also detected in preparations of dispersed human mast cells from skin and in extracts of whole skin. The inhibitor profile and m.w. of carboxypeptidase activity from preparations of dispersed mast cells from skin was similar to that from dispersed mast cells from lung. Mast cell carboxypeptidase had a m.w. on gel filtration of 30,000 to 35,000. The enzyme in crude lysates of dispersed mast cell preparations had optimal activity between pH 8.5 and 9.5 and was inhibited by potato inhibitor, which distinguished it from carboxypeptidase in cultured human foreskin keratinocytes and adult fibroblasts, and from other proteolytic mast cell enzymes. The enzyme activity was also inhibited by EDTA, o-phenanthroline, and, to a small extent, by 8-OH quinoline, but not by Captopril, soybean trypsin inhibitor, or pepstatin. These findings demonstrate that human mast cell secretory granules contain carboxypeptidase in addition to tryptase and chymase. It appears that mast cells from skin may have a higher content of carboxypeptidase than do mast cells from lung.

Carboxypeptidases↗
PubMed1987

Human neutrophils release serine proteases capable of activating prorenin.

Proteases from human neutrophils can generate angiotensin II directly from angiotensin I or angiotensinogen. We examined whether neutrophil protease also influences angiotensin formation by activating human prorenin (also called inactive renin). When incubated with partially purified plasma and amniotic prorenin, sonicates from 10(6) neutrophils resulted in 120 +/- 30% and 1,240 +/- 290% increase in renin activity, respectively. The pH optimum of neutrophil prorenin-activating enzyme(s) is 6.5-7.0, and the activity of the enzyme(s) is inhibited by a mixture of serine protease inhibitors but not by inhibitors of other proteases, suggesting that prorenin-activating enzyme(s) is a neutral serine protease(s). Stimulation of neutrophils by f-met-leu-phe in the presence of cytochalasin B resulted in release of prorenin-activating enzyme(s) in a dose-dependent fashion. We attempted to isolate prorenin-activating enzyme(s) from neutrophil granules using aprotinin-affinity and carboxymethyl cellulose chromatographies. Prorenin-activating enzyme(s) coeluted with cathepsin G and elastase activities. Prorenin activation was greatly inhibited by anticathepsin G antiserum. Purified cathepsin G activated prorenin in a dose-dependent fashion. Elastase probably also contributes to prorenin activation since purified elastase also activated human prorenin. We speculate that this neutrophilic angiotensin-generating system may play a role in the local generation and concentration of angiotensins by influencing multiple steps of the renin-angiotensin system.

Cathepsin G↗
PubMed1986

Inhibition of angiotensin-converting enzyme by des-Leu10-angiotensin I: a potential mechanism of endogenous angiotensin-converting enzyme regulation.

Des-Leu10-angiotensin I is a nonapeptide generated from angiotensin I by the action of carboxypeptidase-like activities residing in the human platelet and mast cell. This nonapeptide was found to inhibit rabbit lung angiotensin-converting enzyme (peptidyl-dipeptide hydrolase, EC 3.4.15.1) with a Ki of 3.1 X 10(-7) M. The mechanism of inhibition was competitive. Inhibition of human serum angiotensin-converting enzyme by des-Leu10-angiotensin I was comparable in magnitude to inhibition by bradykinin and angiotensin III. These results suggest that limited proteolysis of angiotensin I by cells resident in vascular tissue may result in the generation of an endogenous inhibitor of angiotensin-converting enzyme. Such pathways may play roles in controlling levels of vasoactive peptides at local vascular sites.

Angiotensin I↗