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Biomedical subjects

J M Sorrell

Publications and source records attributed to J M Sorrell.

At least 19 recordsLinked to original sources
PubMed2000

Age-related changes in the proteoglycans of human skin.

Skin undergoes dramatic age-related changes in its mechanical properties, including changes in tissue hydration and resiliency. Proteoglycans are macromolecular conjugates of protein and carbohydrate (glycosaminoglycan) which are involved in these tissue properties. In order to examine whether age-related changes in skin proteoglycans may contribute to the age-related changes in the mechanical properties of skin, proteoglycans from human skin of various ages were extracted and analyzed. Samples were obtained from two different fetal ages, from mature skin, and from senescent skin. As a function of age, there is a decrease in the proportion of large chondroitin sulfate proteoglycans (versican) and a concomitant increase in the proportion of small dermatan sulfate proteoglycans (decorin). Based on reactivity with antibodies to various chondroitin sulfate epitopes, fetal versican differs from the versican found in older skin with respect to the chondroitin sulfate chains. Also, the decorin of fetal skin is slightly larger, while the decorin of older skin shows greater polydispersity in both its size and its charge to mass ratio. There are also age-related differences in the size and polydispersity of the core proteins of decorin. The most pronounced change in skin proteoglycans is the appearance in mature skin of a proteoglycan which is smaller than decorin, but which has the same amino terminal amino acid sequence as decorin. This small proteoglycan is abundant in mature skin and may be a catabolic fragment of decorin or an alternatively spliced form of decorin. In light of the known ability of decorin to influence collagen fibrillogenesis and fibril diameter, the appearance of this small decorin-related proteoglycan may have a significant effect on skin elasticity. The observation that proteoglycans in skin show dramatic age-related differences suggests that these changes may be involved in the age-related changes in the physical properties of skin.

Adult↗
PubMed1999

Versican in human fetal skin development.

The extracellular matrix of human fetal skin differs substantially from that of adult skin. Fetal skin contains sparse amounts of fibrillar collagen enmeshed in a highly hydrated amorphous matrix composed of hyaluronan and sulfated proteoglycans. Both fetal and adult skin contain two major interstitial proteoglycans that are extracted by chaotrophic agents and detergents. These are the large chondroitin sulfate proteoglycan versican and the small dermatan sulfate proteoglycan decorin. For this study, proteoglycans extracted from fetal and adult skin were compared on Western blots to determine the relative amounts of versican. Decorin present in the same samples provided an internal standard for these studies. Fetal skin differed from adult skin in that it contained a significantly higher proportion of versican than did adult skin. Immunohistochemical studies compared early-fetal with mid-fetal skin and found that versican was a significant component of the interstitial extracellular matrix at both of these stages of skin development. However, by the mid-fetal period, interstitial versican became restricted to the upper half of the dermis, although versican also continued to be highly expressed around hair follicles, glands, and vasculature in the lower half of the dermis. Fetal skin extracts differed from an adult skin extract by the presence of a 66-kDa protein immunologically related to versican and by the absence of a 17-kDa core protein of a proteoglycan related to decorin. Both of these molecular species may represent degradation products of their respective proteoglycans. Monoclonal antibodies which detect epitopes in native chondroitin sulfate glycosaminoglycan chains recognized versican extracted from fetal skin. However, the tissue distribution of these antigens did not entirely conform to that for versican core protein, suggesting that versican in different regions of the skin may be substituted with glycosaminoglycan chains with different microchemistries. The results of these studies indicate that human fetal skin is structurally different from adult skin in terms of both the distribution and the composition of the large, aggregating chondroitin sulfate proteoglycan versican.

Adult↗
PubMed1999

A monoclonal antibody which recognizes a glycosaminoglycan epitope in both dermatan sulfate and chondroitin sulfate proteoglycans of human skin.

Studies have been initiated to identify various cell surface and matrix components of normal human skin through the production and characterization of murine monoclonal antibodies. One such antibody, termed PG-4, identifies both cell surface and matrix antigens in extracts of human foetal and adult skin as the dermatan sulfate proteoglycans, decorin and biglycan, and the chondroitin sulfate proteoglycan versican. Treatment of proteoglycans with chondroitinases completely abolishes immunoreactivity for all of these antigens which suggests that the epitope resides within their glycosaminoglycan chains. Further evidence for the carbohydrate nature of the epitope derives from competition studies where protein-free chondroitin sulfate chains from shark cartilage react strongly; however, chondroitin sulfate chains from bovine tracheal cartilage fail to exhibit a significant reactivity, an indication that the epitope, although present in some chondroitin sulfate chains, does not consist of random chondroitin 4- or 6-sulfate disaccharides. The presence of the epitope on dermatan sulfate chains and on decorin was also demonstrated using competition assays. Thus, PG-4 belongs to a class of antibodies that recognize native epitopes located within glycosaminoglycan chains. It differs from previously described antibodies in this class in that it identifies both chondroitin sulfate and dermatan sulfate proteoglycans. These characteristics make PG-4 a useful monoclonal antibody probe to identify the total population of proteoglycans in human skin.

Adult↗
PubMed1999

Dynamic expression of proteoglycans during chicken skeletal muscle development and maturation.

Skeletal muscle development is a complex process in which cell migration and adhesion play important roles. Because these cellular activities involve cell surface and extracellular matrix molecules, proteoglycan analysis was performed for developing chick skeletal muscle. Proteoglycans are macromolecular conjugates of protein and carbohydrate found in the extracellular matrix and at the cell surface. In developing muscle, both in vivo and in vitro, there is a development-related progression from synthesis of primarily large proteoglycans at earlier stages to mainly small proteoglycans at later stages. This progression was demonstrated by radiolabeling developing muscle and extracting and characterizing the proteoglycans. The large proteoglycans synthesized earlier in myogenesis have been identified as the large chondroitin sulfate proteoglycan, versican. Among the small proteoglycans synthesized at later stages is the small dermatan sulfate proteoglycan, decorin. Immunolocalization of these proteoglycans shows that versican is initially present in pericellular locations around developing myotubes, whereas decorin is observed in the epimysium early in development, and then its distribution gradually spreads to also include the perimysium and endomysium. Studies of regenerating muscle show that there is a recapitulation of the embryonic pattern of proteoglycan synthesis, which, coupled with the results from embryonic muscle development, suggests a role for versican in some early aspect of myogenesis.

Animals↗
PubMed1999

Creative winds of change: nurses collaborating for quality outcomes.

This article describes the collaboration of two researchers and two clinicians at one rural medical center to develop and implement Phase I of a project that was part of the Quality Indicator Initiative of the American Nurses Association (ANA). Changes in the health care environment led the researchers to develop educational programs that eventually evolved into a pilot research project to explore the feasibility of data collection on ANA Quality Indicators. Collaboration between the researchers and clinicians led to outcomes that relate to future efforts for collecting and analyzing data on clinical outcome indicators.

Cooperative Behavior↗
PubMed1999

Connecting across the miles: interdisciplinary collaboration in the evaluation of critical thinking.

A pilot study in which faculty from nursing and English departments at two universities in different states shared a common evaluation tool and collaborated through e-mail to evaluate the evidence of critical thinking in writing portfolios of baccalaureate and masters' nursing students. Loxley's (1997) four processes--assessment, building, managing the process, and evaluating--are used as a framework for describing collaboration among the disciplines in the two universities. Social exchange theory was used to explain the collaboration between participants. All six professors learned a great deal from studying and scoring the writings, but they learned most from each other through their e-mail dialogue.

Computer Communication Networks↗
PubMed1998

Nurses as writers.

Although nurses are expected to be competent in on-the-job writing, most nurses receive little formal education in the types of writing required in practice. Thus, it is important for faculty in schools of nursing to include in the curricula various types of writing assignments to help students develop these skills. This article describes how at one university a course, "Nurses as Writers," provides opportunities for students to learn and practice the types of writing needed in their professional careers.

Curriculum↗
PubMed1996

Distribution of keratan sulphate and chondroitin sulphate in wild type and white mutant axolotl embryos during neural crest cell migration.

In embryos of the white mutant axolotl, prospective pigment cells are unable to migrate from the neural crest (NC) due to a deficiency in the subepidermal extracellular matrix (ECM). This raises the question of the molecular nature of this functional defect. Some PGs can inhibit cell migration on ECM molecules in vitro, and an excess of this class of molecules in the migratory pathways of neural crest cells might cause the restricted migration of prospective pigment cells seen in the white mutant embryo. In the present study, we use several monoclonal antibodies against epitopes on keratan sulphate (KS) and chondroitin sulphate (CS) and LM immunofluorescence to examine the distribution of these glycosaminoglycans at initial (stage 30) and advanced (stage 35) stages of neural crest cell migration. Most KS epitopes are more widely distributed in the white mutant than in the wild type embryo, whereas CS epitopes show very similar distributions in mutant and wild type embryos. This is confirmed quantitatively by immunoblotting: certain KS epitopes are more abundant in the white mutant. TEM immunogold staining reveals that KS as well as CS are present both in the basal lamina and in the interstitial ECM in both types of embryos. It remains to be investigated whether the abundance of certain KS epitopes in the white mutant embryo might contribute to the deficiency in supporting pigment cell migration shown by its ECM.

Ambystoma↗
PubMed1995

Immunology of chondroitin/dermatan sulfate.

Variable substitutions and locations of the sulfate esters along the backbone of chondroitin/dermatan sulfate chains, combined with their carbohydrate structures, present topographies to immune systems which can be recognized as antigenic. This has led to the development of a number of monoclonal antibodies which recognize distinct epitopes in the native structures of these glycosaminoglycan chains. In some studies, the original chondroitin/dermatan sulfate proteoglycan was digested with chondroitinase enzymes before being used as an immunogen. in this case, the linkage oligosaccharides remaining bound to the core protein contain a modified (4,5-unsaturated) hexuronic acid derivative at their non-reducing ends as a result of the eliminase mechanism of the enzyme. This 'haptenic' structure is highly antigenic and has led to the development of a number of monoclonal antibodies which recognize this structure as part of their epitopes. Examples of the use of some of these monoclonal antibodies for localization of proteoglycan structures in tissue sections and on transblots are described. The precise structures are known for only a few of the native epitopes recognized by these monoclonal antibodies. Recent analytical methods have been developed for determining structures of chondroitin sulfate oligosaccharides. An example of the use of these methods to analyze the structures of the non-reducing termini of chondroitin/dermatan sulfate chains is discussed. The results show their potential value for quantifying the native epitope recognized by a monoclonal antibody, designated 3B3, which recognizes chains terminated by glucuronic acid-N-acetylgalactosamine-6-sulfate. Such methods should be useful for determining the epitope structures for other monoclonal antibodies in this class.

Antibodies, Monoclonal↗
PubMed1995

Interviews in qualitative nursing research: differing approaches for ethnographic and phenomenological studies.

Interviews form an essential part of data collection for many qualitative nursing studies. Information about how to individualize interview formats to meet the purpose and style of specific qualitative research approaches, however, is not readily accessible to the researcher. This paper offers an overview of use of the interviewer as an instrument in qualitative research, as well as ways in which the differing purposes and styles of ethnographic and phenomenological research approaches affect the format for the interview.

Anthropology, Cultural↗
PubMed1995

From Carper's patterns of knowing to ways of being: an ontological philosophical shift in nursing.

Carper's 1978 article in the premiere issue of Advances in Nursing Science encouraged nurses to consider four fundamental patterns of knowing. Through illustrations from literature and the performing arts, the authors address Carper's patterns of knowing in the context of an emerging philosophical shift. First, they critique the major strengths and limitations of the article. Next, they explore an emerging philosophical shift in nursing from Carper's epistemological focus to ontological reflections on ways of being. Finally, they discuss the significance of the emerging philosophical shift and the ways of being for the science-art of nursing.

Cognition↗
PubMed1994

Remembrance of things past through writing: esthetic patterns of knowing in nursing.

The writing process offers a valuable medium for informing esthetic knowing in nursing. First, characteristics of esthetic patterns of knowing in nursing are described. Esthetic knowing in world literature is then illustrated through the writings of Proust. Next, composition theories and research are used to identify ways in which writing can shape esthetic knowing. Finally, the author presents implications for the use of writing to foster esthetic patterns of knowing in nursing.

Esthetics↗
PubMed1993

Developmental regulation of a mucinlike glycoprotein selectively expressed on natural killer cells.

Natural killer (NK) cells are CD3:TCR-, CD16+, CD56+ large granular lymphocytes capable of recognizing and eliminating a variety of virus-infected, malignant, and antibody-coated target cells. Two functionally distinct populations of peripheral blood NK cells can be differentiated by their surface expression of an isoform of the neural cell adhesion molecule (CD56). CD56bright NK cells have the attributes of an undifferentiated cell, in that they proliferate in response to exogenous cytokines, but exert poor cytolytic activity. CD56dim NK cells have the attributes of a more differentiated cell, in that they proliferate poorly in response to exogenous cytokines, but are potent cytolytic effector cells. Here we describe the molecular characterization of a NK cell restricted epitope (PEN5) that is selectively expressed on the functionally differentiated CD56dim NK cells. PEN5+ NK cells proliferate poorly in response to interleukin 2 (IL-2), but are potent cytolytic effectors, whereas PEN5- NK cells proliferate in response to IL-2, but are poor cytolytic effectors. Biochemical and immunochemical analyses reveal the PEN5 epitope to be an unusual sulfated poly-N-lactosamine carbohydrate related to keratan sulfate glycosaminoglycans. Immunoprecipitates prepared using a monoclonal antibody reactive with PEN5 include two polydisperse membrane-bound glycoproteins, PEN5 alpha (120-170 kD) and PEN5 beta (210-245 kD). Enzymatic deglycosylation reduces the apparent molecular weight of both PEN5 isoforms by 80-90%, and classifies PEN5 beta as a mucinlike glycoprotein. The surface expression of the PEN5 epitope is downmodulated by stimuli that induce NK cell proliferation, and it is absent from leukemic NK cells of patients with granular lymphocyte proliferative disorder. Taken together, these results indicate that PEN5 is a developmentally regulated poly-N-lactosamine epitope associated with a mucin-type glycoprotein, whose expression is restricted to the population of nonproliferative NK cells fully committed to cytolytic effector function.

Amino Sugars↗
PubMed1993

Human keratinocytes contain keratin filaments that are glycosylated with keratan sulfate.

We have reported strong intracytoplasmic immunoreactivity for anti-keratan sulfate monoclonal antibodies in human keratinocytes. Consequently, ultrastructural immunogold studies were undertaken to identify the cytoplasmic components responsible for this immunoreactivity. Immunogold labeling of cultured keratinocytes identified keratin filaments as a source of keratan sulfate epitopes. Immunolabeling also marked desmosomal cytoplasmic plaques and amorphous electron-dense bodies. These observations were confirmed for epidermal keratinocytes of human skin. Further evidence was obtained that some keratins have epitopes for anti-keratan sulfate antibodies by Western blot analyses following fractionation of proteins by sodium dodecyl sulfate gel electrophoresis. Four bands were detected with apparent molecular weights of 58, 54, 50, and 48 kDa that reacted with anti-keratin monoclonal antibody mixture AE1/AE3. Keratins of 58 and 56 kDa immunoreacted with anti-keratan sulfate antibody 8C2 while all four keratins immunoreacted with anti-keratan sulfate antibody 5D4. Endo-beta-D-galactosidase and keratanase, enzymes that degrade keratan sulfate, removed all, or a portion, of specific keratan sulfate epitopes from keratin extracts. These results demonstrate that a portion of the cytoplasmic anti-keratan sulfate immunoreactivity is due to keratins that are glycosylated with carbohydrates that contain keratan sulfate epitopes or that keratan sulfate-containing molecules bind or comigrate in SDS-polyacrylamide gels with cytokeratins.

Actin Cytoskeleton↗
PubMed1993

Structural domains in chondroitin sulfate identified by anti-chondroitin sulfate monoclonal antibodies. Immunosequencing of chondroitin sulfates.

Monoclonal antibodies have been developed that recognize epitopes in native chondroitin sulfate chains. One of these antibodies, CS-56, reportedly recognizes chondroitin 4- and 6-sulfates. However, this antibody, and four other anti-chondroitin sulfate antibodies, 4C3, 4D3, 6C3 and 7D4, do not recognize epitopes in chondroitin sulfate chains from Swarm rat chondrosarcoma proteoglycan, an indication that native chondroitin sulfate epitopes are more structurally complex than the standard 0-, 4-, and 6-sulfated disaccharide repeats that constitute the backbone of chondroitin sulfate chains. A series of limited chondroitinase digestions was performed on the large aggregating proteoglycan monomer extracted from embryonic chick chondrocyte cultures to identify the digestion parameters required to release the different native chondroitin sulfate epitopes. Some epitopes were more accessible to enzymatic digestion than other epitopes. The approximate location of epitopes was determined by measuring the size of undigested oligosaccharides retained on the core protein following a limited digestion, and correlating this with the level of immunoreactivity for the different antibodies. These analyses identified the locations of three different antigenic domains. Domain 1 resides at the linkage region and contains epitopes for two of the five antibodies, and a portion of the epitopes for a third antibody. Domain 2 lies in the interior of the chain and contains epitopes for three of the five antibodies. Domain 3 resides at the non-reducing terminus and does not contain epitopes for any of the anti-chondroitin sulfate antibodies used in this study. These results indicate that specific native chondroitin sulfate epitopes are non-randomly distributed within the linear framework of chondroitin sulfate chains.

Animals↗
PubMed1993

Skin anatomy and antigen expression after burn wound closure with composite grafts of cultured skin cells and biopolymers.

Closure of large skin wounds (i.e., burns, congenital giant nevus, reconstruction of traumatic injury) with split-thickness skin grafts requires extensive harvesting of autologous skin. Composite grafts consisting of collagen-glycosaminoglycan (GAG) substrates populated with cultured dermal fibroblasts and epidermal keratinocytes were tested in a pilot study on full-thickness burn wounds of three patients as an alternative to split-thickness skin. Light microscopy and transmission electron microscopy showed regeneration of epidermal and dermal tissue by 2 weeks, with degradation of the collagen-GAG implant associated with low numbers of leukocytes, and deposition of new collagen by fibroblasts. Complete basement membrane, including anchoring fibrils and anchoring plaques, is formed by 2 weeks, is mature by 3 months, and accounts for the absence of blistering of healed epidermis. All skin antigens tested (involucrin, filaggrin, laminin, collagens IV and VII, fibronectin, and chondroitin-sulfate) were expressed by 16 days after grafting. This cultured skin analogue provides an experimental alternative to split-thickness skin graft that develops histiotypic markers of skin anatomy and antigen expression after wound closure.

Adolescent↗