Search PubMed⌕ Search

Biomedical subjects

J C Edwards

Publications and source records attributed to J C Edwards.

At least 91 records · Page 5Linked to original sources
PubMed1993

The apical Cl/HCO3 exchanger of beta intercalated cells.

There are two types of intercalated cells of the renal collecting duct; one secretes H+ and the other secretes HCO3-. The H(+)-secreting form has an apical vacuolar H(+)-ATPase and a basolateral Cl/HCO3 exchanger that cross-reacts with antibodies to band 3, the product of the AE1 gene. The HCO3(-)-secreting form has a basolateral vacuolar H(+)-ATPase and an apical Cl/HCO3 exchanger, whose identity has not been established previously. Apical membrane vesicles of beta intercalated cells purified from rabbit kidney cortex contain both an electroneutral Cl/HCO3 exchange activity and polypeptides that react with antibodies to band 3 on Western blots. Furthermore, both primary cultures of HCO3(-)-secreting intercalated cells and an immortalized cell line derived from these cells express AE1 and have an apical Cl/HCO3 exchanger. Apical membranes purified from these cells contain a 100-kDa polypeptide that cross-reacts with antibody to the cytoplasmic domain of band 3. These data suggest that the apical Cl/HCO3 exchanger of HCO3(-)-secreting intercalated cells is band 3.

Animals↗
PubMed1993

Clinical skills acquired during third-year surgical clerkships.

An instrument was developed to survey third-year medical students about their experience with 18 clinical skills that are generally recognized as required learning for the third-year surgical clerkship. The same instrument was adapted to ascertain which surgical skills 25 fourth-year medical students, 25 surgical residents, and 25 practicing surgeons thought should be acquired during the third-year surgical clerkship. None of these evaluators had completed medical school or residency at our institution. A remarkable degree of conformity was found in the rankings of the 18 clinical skills by senior students, surgical residents, and practicing surgeons; fourth-year students rated only central venous line placement and simple operative procedures as significantly more important than did more senior evaluators. The third-year medical students' actual surgical clerkship experience with 10 out of the 18 skills was significantly below the overall competency levels desired by the graduate groups. Our survey demonstrates that both students and graduates attach similar importance to the acquisition of clinical skills in the third-year surgical curriculum. The instrument utilized in this study to measure students' experience and satisfaction with this phase of their education was reliable, the measurements were consistent, and this information was useful in the evaluation and modification of the curriculum.

Catheterization, Central Venous↗
PubMed1993

Evaluation of an electronic message strip to recruit smokers to a smoking cessation program.

Knowledge of outcome is essential when analyzing effectiveness of educational programs. Although quantitative data can be analyzed more rigorously than other forms of data, quantitation of behavioral processes is often difficult. To promote our smoking-cessation program we designed a method that relies on electronic message strips and a dedicated telephone line capable of providing quantitative outcome information. This approach appears quite versatile and shows that the electronic message strip is a surprisingly ineffective method of enlisting subjects into a smoking-cessation program in our hospital.

Equipment Design↗
PubMed1993

Intercellular adhesion molecules in normal synovium.

The vasculature of normal synovium and skin has been examined for the presence of molecules believed to be involved in intercellular adhesion and whose expression on endothelial cells in vitro is known to be upregulated by cytokines. Synovium was obtained from clinically and histologically normal joints removed during amputations for proximal sarcomata. Skin was obtained from healthy volunteers. Cryostat sections of tissues were assessed by immunohistochemistry and microdensitometry for the presence of E-selectin using monoclonal antibody 1.2B6, intercellular adhesion molecule-1 (ICAM-1) using monoclonal antibody 6.5B5 and vascular cell adhesion molecule (VCAM-1) using monoclonal antibody 1.4C3. Both E-selectin and ICAM-1 were present on a proportion of normal synovial venules but at a level comparable to or lower than that found on dermal vessels. (Staining intensities given as mean absorption indices: superficial synovium 1.2B6: 9.9 +/- 11.4, 6.5B5: 10.2 +/- 12.0, deep synovium 1.2B6: 6.6 +/- 9.9, 6.5B5: 24.6 +/- 15.7, skin 1.2B6: 13.1 +/- 16.6, 6.5B5: 36.4 +/- 12.9.) E-selectin expression was most prominent on small superficial venules in synovium and ICAM-1 most strongly expressed on larger, deep venules. VCAM-1 was found at low levels on cells associated with vessel walls but no significant endothelial staining was seen in either type of tissue. VCAM-1 was also present on cells of the synovial lining layer. Some of the findings in synovium could have been attributable to tumour related cytokine release, but the consistency of findings and comparability to skin suggest that this is relatively unlikely.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Palisading cells of rheumatoid nodules: comparison with synovial intimal cells.

OBJECTIVES: The palisading cells of rheumatoid nodules share certain features with synovial intimal cells. The similarities between the two cell populations have been reassessed using new cytochemical markers. METHODS: Cell populations in cryostat sections of non-inflamed, rheumatoid and osteoarthritic synovial tissues, and rheumatoid nodules were assessed for the presence of CD68, prolyl hydroxylase, vascular cell adhesion molecule 1 (VCAM-1), and the alpha 4 and beta 1 integrin chains, and the activity of uridine diphosphoglucose dehydrogenase (UDPGD) and nonspecific esterase. RESULTS: Synovial intimal cells formed a dual population of macrophages (nonspecific esterase positive, strongly positive for CD68) and fibroblastic cells (prolyl hydroxylase positive). The latter showed prominent VCAM-1 expression and high UDPGD activity as previously reported and also prominent beta 1 integrin chain expression. Palisading cells similarly proved to be a dual population of macrophages and fibroblastic cells. In contrast with synovial intima, however, the fibroblastic cells lacked UDPGD activity and expression of VCAM-1 and showed no preferential expression of the beta 1 integrin chain. The exception to this rule was where nodules contained central clefts, which were lined with cells showing all the features associated with synovial intimal cells. CONCLUSION: Palisading cells are a mixture of macrophages and fibroblasts, but the latter show no evidence of synoviocyte differentiation. Cells with features of synoviocytes may occur lining clefts within areas of necrobiosis.

Antigens, CD↗
PubMed1993

Vascular cell adhesion molecule 1 and alpha 4 and beta 1 integrins in lymphocyte aggregates in Sjögren's syndrome and rheumatoid arthritis.

OBJECTIVES: Interactions between vascular cell adhesion molecule 1 (VCAM-1) and its ligand, the alpha 4/beta 1 integrin, have been shown to be important in a number of cellular events in vitro. To assess the importance of such interactions in the development of lymphocytic infiltration in diseased tissue the distribution of the two ligands has been studied immunohistochemically. METHODS: Cryostat sections of labial tissue from patients with Sjögren's syndrome, normal labial tissues, rheumatoid synovia, and normal tonsils were stained using antibodies to VCAM-1, alpha 4 and beta 1 integrin chains, and markers for T cells, B cells, macrophages, and follicular dendritic reticulum cells (FDRCs), visualised using alkaline phosphatase and fast red. RESULTS: Staining patterns for VCAM-1 and integrin chains in lymphocyte aggregates in synovial and labial tissues were similar. VCAM-1 staining was found on both vascular and ramifying dendritic cells at the centre of large T cell aggregates and in all aggregates where there was a central clustering of B cells. VCAM-1 colocalised with, but also extended beyond, staining for the FDRC marker R4/23. Staining for the alpha 4 and beta 1 integrin chains was more widespread than staining for VCAM-1, with no significant increase in staining at sites of maximum VCAM-1 staining. In tonsils VCAM-1 and R4/23 codistributed in germinal centres, but staining for the alpha 4 and beta 1 integrin chains was chiefly seen in T lymphocyte areas. CONCLUSIONS: VCAM-1 may be more important in determining the distribution of B than T lymphocytes in lymphocytic infiltration of non-lymphoid tissue. Unlike the follicles of lymphoid tissue, ectopic follicle-like structures in non-lymphoid tissues may form by immigration of B cells via VCAM-1+ vessels at the centre of T cell aggregates.

Arthritis, Rheumatoid↗
PubMed1993

Giant cells in arthritic synovium.

OBJECTIVES: Giant cells are commonly present in inflamed synovium, often in close association with the intimal layer. The nature of these multinucleate cells has been reassessed using new cytochemical and immunochemical techniques. METHODS: Cryostat sections of non-inflamed, rheumatoid arthritic and osteoarthritic synovia were analysed for the presence of CD68 and non-specific esterase, markers associated with macrophages; activity of uridine diphosphoglucose dehydrogenase, associated with fibroblast-like synoviocytes; and tartrate resistant acid phosphatase and the vitronectin receptor subunit CD51, associated with osteoclasts. RESULTS: Giant cells were not seen in non-inflamed tissue. In diseased tissue giant cells in the intimal layer fell into two major groups: CD68 negative or dull cells with high uridine diphosphoglucose dehydrogenase (UDPGD) activity suggestive of true synoviocyte polykaryons; and CD68 positive cells with low UDPGD activity suggestive of macrophage polykaryons. The two groups were seen in samples from patients with rheumatoid arthritis (RA) and patients with osteoarthritis (OA), but the former were more prominent in OA and the latter in RA. Most CD68 positive giant cells also showed tartrate resistant acid phosphatase activity and prominent expression of CD51. As such they were histochemically indistinguishable from osteoclasts, but their bone resorbing capacity remains unknown. CONCLUSIONS: Giant cells in arthritic synovium appear to be of two types, one related to true synoviocytes and one to macrophages.

Acid Phosphatase↗
PubMed1993

Surgery resident selection and evaluation. A critical incident study.

This article reports a study of the process of selecting and evaluating general surgery residents. In personnel psychology terms, a job analysis of general surgery was conducted using the Critical Incident Technique (CIT). The researchers collected 235 critical incidents through structured interviews with 10 general surgery faculty members and four senior residents. The researchers then directed the surgeons in a two-step process of sorting the incidents into categories and naming the categories. The final essential categories of behavior to define surgical competence were derived through discussion among the surgeons until a consensus was formed. Those categories are knowledge/self-education, clinical performance, diagnostic skills, surgical skills, communication skills, reliability, integrity, compassion, organization skills, motivation, emotional control, and personal appearance. These categories were then used to develop an interview evaluation form for selection purposes and a performance evaluation form to be used throughout residency training. Thus a continuum of evaluation was established. The categories and critical incidents were also used to structure the interview process, which has demonstrated increased interview validity and reliability in many other studies. A handbook for structuring the interviews faculty members conduct with applicants was written, and an interview training session was held with the faculty. The process of implementation of the structured selection interviews is being documented currently through qualitative research.

Clinical Competence↗
PubMed1993

Expression of vascular cell adhesion molecule-1 in normal and inflamed synovium.

BACKGROUND: The intercellular adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) has been implicated in a number of interactions between leukocytes and cells of lymphoid and connective tissue, including endothelial cells. Such interactions within synovial tissue may be important in the pathogenesis of rheumatoid arthritis. EXPERIMENTAL DESIGN: The expression of VCAM-1 on specific cell populations in normal and inflamed synovium was investigated using a range of double-labeling techniques. RESULTS: The strongest VCAM-1 staining was found to be confined to four nonmacrophage populations (as judged in terms of CD68 expression, nonspecific esterase activity, content of prolyl hydroxylase and activity of uridine diphosphoglucose dehydrogenase): (i) type B synoviocytes, (ii) vascular wall cells outside the endothelial layer, (iii) scattered stromal cells with cytoplasmic processes, and (iv) cells resembling follicular dendritic reticulum cells in lymphoid aggregates with germinal centers (in the three samples of rheumatoid arthritic tissue where these were present). Some macrophages of the synovial intima showed weak VCAM-1 staining. Endothelial cell staining was seen but it was consistently weaker than the staining of cells of group ii. CONCLUSIONS: The four cell populations described as showing bright staining for VCAM-1 may all be involved in local interactions with leukocytes of the macrophage or lymphoid series subsequent to initial leukocyte entry into the tissue. Expression of VCAM-1 by these cells may play a role in such interactions.

Arthritis, Rheumatoid↗
PubMed1993

Leukocytes: their role in the etiopathogenesis of skin damage in venous disease.

The role of leukocytes in tissue damage in the liposclerotic skin of venous disease has been investigated. Twenty-eight skin biopsy specimens were obtained from 23 patients with varicose veins of the lower limb, with a spectrum of skin injury ranging from normal to severe liposclerosis. In no patient was a venous ulcer present. Immunohistochemistry was used to determine the cell types present and provide an indication of their activity. The predominant infiltrating cell types present were T lymphocytes and macrophages. B cells and neutrophils were rarely seen. As described previously, the capillaries were greatly increased in number in the papillary dermis and exhibited grossly increased expression of factor VIII-related antigen and major histocompatibility complex class II. Surprisingly, expression of adhesion molecules endothelial leukocyte adhesion molecule-1 and vascular cell adhesion molecule were not elevated, but intercellular adhesion molecule-1 expression did increase in more severely diseased skin. Perivascular fibrin was seen occasionally, but there was no evidence of microvascular occlusion. Staining for the cytokine tumor necrosis factor-alpha was not increased in liposclerotic skin. Dermal staining for both interleukin (IL)-1 alpha and IL-1 beta was increased in severely liposclerotic skin, but this was not seen at an early stage. Epidermal staining for IL-1 alpha and IL-1 beta was not increased. All changes were confined to the subpapillary region of the skin. These findings demonstrate that accumulation of macrophages and T cells is an event associated with the development of liposclerotic skin changes that may lead to ulceration in venous disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1993

Comparison of surface fibroblastic cells in subcutaneous air pouch and synovial lining: differences in uridine diphosphoglucose dehydrogenase activity.

In contrast to synovial tissue, rat subcutaneous air pouch lining was found to lack cells showing high activity of uridine diphosphoglucose dehydrogenase, an enzyme involved in hyaluronan synthesis. This indicates that the properties of cells on the surface of synovium are not determined simply by tissue cavitation. Shearing forces may be more important in inducing the specialized behaviour of synovial surface fibroblasts.

Air↗
PubMed1993

Uridine diphosphoglucose dehydrogenase activity in normal and rheumatoid synovium: the description of a specialized synovial lining cell.

Although synovial lining cells (SLC) have been implicated in the production of hyaluronan (HA), which is found at particularly high concentrations in synovial fluid, the degree to which individual cells within the synovium are adapted to this particular function remains to be elucidated. Uridine diphosphoglucose dehydrogenase (UDPGD) activity is the irreversible, rate-limiting step in the production of UDP-glucuronate, an essential monosaccharide in the synthesis of HA. We have assessed the UDPGD activity, microdensitometrically, in individual lining cells of normal and rheumatoid (RA) synovium, using a modified quantitative cytochemical method. In normal synovium, high activity was confined to the cells of the lining with negligible activity in the deeper subintima. The mean UDPGD activity/cell in lining cells of rheumatoid synovium was significantly lower than the activity in normal SLC. In some samples of RA and normal synovium, a bimodal distribution of cells was evident in the lining on the basis of UDPGD activity, a zone of cells in the basal layers with high UDPGD activity and a separate population of cells in more superficial layers with relatively low UDPGD activity. The results suggest that a particular population of cells is present, consistently in normal and more variably in RA synovial lining, which have high UDPGD activity/cell and may be involved in the production of HA. Furthermore, in RA synovium both the UDPGD activity/cell and the relative proportion of these cells within the lining appear to be decreased.

Arthritis, Rheumatoid↗
PubMed1992

Light microscopic characterization of the fibroblast-like synovial intimal cell (synoviocyte).

OBJECTIVE: To reassess synovial intimal cell populations by light microscopy. METHODS: Non-inflamed, rheumatoid and osteoarthritic synovia were analyzed as tissue sections and cytospin preparations by a series of combined immunohistochemical and cytochemical staining techniques. RESULTS: Two populations of intimal cells were identified. The first carried macrophage markers. The second showed high uridine diphosphoglucose dehydrogenase (UDPGD) activity, minimal cytoplasmic CD68, absent non-specific esterase (NSE) activity, and absent leukocyte and endothelial antigens. The majority of these cells showed a high content of prolyl hydroxylase. CONCLUSION: Combined cytochemical staining for NSE and UDPGD activity allows effective separation of intimal cell populations. We suggest that the cells of high UDPGD activity are the fibroblast-like or type B synovial intimal cells defined by electron microscopy. High UDPGD activity probably reflects a preferential ability to synthesize glycosaminoglycans, including hyaluronan.

Antigens, CD↗
PubMed1992

The monoclonal antibody MEL-14 can block lymphocyte migration into a site of chronic inflammation.

The effect of MEL-14, a monoclonal antibody which binds to the lymphocyte homing receptor (MEL-14 Ag) on lymphocytes for peripheral lymph node (PLN) high endothelial venules (HEV), was investigated on lymphocyte migration into a delayed-type hypersensitivity (DTH)-like lesion produced by sensitization and challenge to Bordetella pertussis vaccine (BPV). Pretreatment of lymphocytes with saturating concentrations of MEL-14 caused a highly significant inhibition of lymphocyte migration into the chronically inflamed site and PLN. This finding suggests that lymphocyte migration into the BPV-induced site of chronic inflammation may be regulated by the same mechanism as lymphocyte migration into the PLN. It further indicates that the ligand for the MEL-14 Ag adhesion molecule, recognized by lymphocyte which home to the PLN, may also be expressed on HEV-like vessels at sites of BPV-induced chronic inflammation.

Animals↗
PubMed1992

Lymphocyte migration in the mouse. I. Time course of cell accumulation and the effect of antigen sensitisation and challenge in a murine model of chronic inflammation.

The effect of time and of antigen sensitisation and challenge on lymphocyte migration into a site of chronic inflammation has been examined in the mouse. Enhanced lymphocyte migration occurred at sites of chronic inflammation after sensitisation and challenge to Bordetella pertussis vaccine (BPV). Biphasic migration was observed with time (5 min to 24 h), the initial very rapid but transient localisation at the inflamed site being followed by a second slower more sustained influx of cells. Increased localisation was also obtained with time in the lymphoid tissues and was accompanied by a parallel decrease in the number of cells present in the blood. The relative importance of antigen sensitisation and challenge for lymphocyte migration to a site of chronic inflammation has also been assessed. Lymphocyte migration into the inflamed site was partially dependent on the immunological status of the injected lymphocytes, but the presence or absence of antigen at the site of inflammation was the major factor which determined the degree of migration to the site.

Animals↗
PubMed1992

Lymphocyte migration in the mouse. II. Differential B and T-lymphocyte migration into a site of chronic inflammation.

Different patterns of B and T-lymphocyte migration were observed in normal mice and in animals with a site of chronic inflammation. The early migration of lymphocytes into a site of chronic inflammation, induced by sensitisation and challenge to Bordetella pertussis vaccine (BPV), comprised mainly B-cells. Subsequently, a greater influx of T-cells occurred as the inflammation progressed. The lymphocyte population in the inflammatory exudate was composed of equal numbers of B and T-cells throughout the 30 day time course. Preferential migration of B-cells to Peyer's patches (PP) and T-cells to peripheral lymph nodes (PLN) occurred in both normal mice and animals with a site of chronic inflammation. In contrast, B-cells migrated preferentially to the spleen in normal mice while in mice with chronic inflammation a greater migration of T-cell was observed. These findings indicate the presence of homing receptors for PP on B-cells and of PLN homing receptors on T-cells, with their distribution unaffected during the development of the inflammatory response. In contrast, the inflammatory process did alter the type of cell migrating into the spleen which may reflect an increase in antigen presentation in the mice challenged with BPV.

Animals↗