Value importance and value congruence as determinants of trust in health policy actors.

The paper examines levels and determinants of trust in a health care system and in key actors in the health policy community. Talcott Parsons theorizes that the sharing of common values is a necessary condition for interpersonal trust to exist; this paper tests that notion at the level of systemic (institutional) trust. The paper reports findings of a 1999 survey of 493 randomly selected residents of Calgary, Alberta, Canada. It uses multiple regression analysis to identify the determinants of three different types of trust-generalized systemic trust, fiduciary trust, and generalized trust in particular actors' input to health system changes. Among the numerous independent variables, special attention is devoted to the degree of congruence or incongruence between the importance which respondents attach to one of the values enunciated in the Canada Health Act-namely, 'accessibility' (equal access to quality health care)-and the importance which respondents believe is attached to that value by the Regional Health Authority and by the Premier of the province. Both value importance and value congruence on equal accessibility are found to be important factors explaining variation in all three types of trust. In explaining levels of trust in the Premier on the issue of health care system reform, congruence on equal accessibility proved to be even more important than such factors as political partisanship, political cynicism, and personal experience as a patient in the health care system. Findings also suggest that there is an emotional component to systemic trust.

Serum levels of vascular endothelial growth factor (VEGF) are markedly elevated in patients with Wegener's granulomatosis.

OBJECTIVES: Necrotizing vasculitis and granuloma formation are the predominant features of Wegener's granulomatosis (WG). We have investigated the importance of vascular endothelial growth factor (VEGF) in monitoring disease activity in WG. METHODS: Serum VEGF levels were determined in 23 patients with active WG, 21 healthy controls and 25 patients with urinary infection, by ELISA using commercially available antibodies to VEGF. RESULTS: VEGF levels were enormously elevated in patients with WG compared to both controls and patients with urinary infection (P < 0.0001). Of the 23 patients, 21 (91.3%) had VEGF levels above the cut-off value (3.3 ng/ml, calculated as the mean of the controls + 2 S.D.). Further analysis of the data showed that VEGF levels did not correlate with age, sex, incidence of classic antineutrophil cytoplasmic antibodies (c-ANCA) or duration of the disease (P > 0.05), but there was correlation with disease activity (r = 0.51, P < 0.01). VEGF levels were higher in patients with major compared to those with minor disease activity (P < 0.01). However, there was no significant correlation between VEGF levels and the Birmingham scores for vascular activity and damage. CONCLUSION: VEGF levels are raised in WG patients compared to normal controls and may be a marker of disease activity. Further studies on serial blood samples from a large cohort of patients with WG and other systemic vasculitides are needed to evaluate the specificity and usefulness of VEGF levels in monitoring disease activity.

Glucosaminylmuramyl dipeptide (GMDP) modulates endothelial cell activities in vitro but has no effect on angiogenesis in vivo.

OBJECTIVE AND DESIGN: The aim of the study was to evaluate the effects of GMDP on angiogenesis in vivo and as a modulator of human umbilical vein endothelial cell proliferation, cell surface antigen expression and cell adhesion in vitro. MATERIALS: Human umbilical vein endothelial cells (HUVEC), fertilized white leghorn chicken eggs, antibodies against adhesion molecules and glucosaminylmuramyl dipeptide (GMDP). TREATMENT: GMDP [0.01-100 micrograms/ml] applied to cell cultures for 6-72 h and to the chick chorioallantoic membrane (CAM) for four days. METHODS: Angiogenic activity of GMDP in vivo was assessed using the CAM assay; HUVEC proliferation was measured by tritiated thymidine incorporation and cell cycle studies; cell surface antigen expression by indirect immunofluorescence and flow cytometry; cell adhesion by quantification of [3H]-thymidine labeled leukocyte adherence to HUVEC monolayers. Statistical analysis was performed using one-way ANOVA and if necessary was followed by Duncan's multiple range test for variables. RESULTS: GMDP induced [3H]-thymidine incorporation in a concentration- and time-dependent manner (p < 0.003) and significantly increased the porportion of cells in the S phase of the cell cycle (p < 0.03). It weakly augmented the expression of ICAM-1 and CD31 but not adhesion of leukocytes to HUVEC monolayers GMDP was not angiogenic in the CAM assay. CONCLUSIONS: GMDP can modulate endothelial cell activity without the induction of angiogenesis in vivo which may have implications for its use as a therapeutic agent.

Reactivity of 87 monoclonal antibodies against tissues in vivo and resting and irradiated endothelial cells in vitro.

Altered expression of vascular endothelial cell (EC) surface antigens in response to irradiation is one of the early events of radiation-induced damage. Using flow cytometry, we investigated the immunocytochemical reactivity of a blind panel comprising 87 mAbs submitted to the endothelial section of the 6th International Workshop on Human Leukocyte Differentiation Antigens with irradiated and resting human dermal microvascular endothelial (HDME) and EA cell lines. Monolayers of irradiated cells received a single 5 Gy dose of 72 h prior to staining but were otherwise treated the same as resting cells. For comparative purposes we have also examined the immunohistochemical reactivity of the mAb panel with EC in ovarian tumour, Wilms' tumour and human placenta. In the flow cytometry experiments 42 and 44 mAbs stained HDME and EA cells respectively and while no antibody stained irradiated but not unirradiated cells, upregulation was seen for CD31, CD34, CD141 and CD146 in irradiated cells. The upregulation of thrombomodulin (CD141) is noteworthy since it is a marker of EC damage and thus may be a useful reagent in investigations of vascular injury. Comparison with tissue staining showed that 21 mAbs were reactive with at least one tissue but not with either EA or HDME cells. Nine mAbs showed no cross reactivity with tissue and of these one reacted with EA cells only.

Expression of the vascular endothelial growth factor receptor, KDR, in human placenta.

Vascular endothelial growth factor (VEGF) is a heparin-binding growth factor known to act directly on vascular endothelial cells by promoting cell proliferation and permeability. To date, 3 structurally related cell surface receptors for VEGF, Flt-1, Flt-4 and KDR, have been identified and shown to be human type III receptor tyrosine kinases. The establishment of a vascular network is crucial to the development of the placenta and occurs through both angiogenesis and vasculogenesis. The signals controlling these processes are unclear. Immunohistochemical and in situ hybridisation techniques have localised VEGF in the trophoblast layers and VEGF binding to placental vascular endothelial cells and haemangioblasts has been shown, suggesting a role for VEGF and its receptors in development of the vascular network. In this study we have used specific antibodies to localise KDR and endothelial cells in 1st and 3rd trimester human placenta. The staining showed a colocalisation of KDR with endothelial cells and haemangioblasts. No staining of trophoblast cells was observed, but strong staining of the endothelial cells was seen in the villous stroma adjacent to areas of trophoblast proliferation.

Localisation and cellular origin of hyaluronectin.

Hyaluronectin is an extracellular matrix glycoprotein which specifically binds to hyaluronan. Isoforms of hyaluronectin are present in nervous and mesenchymal tissues but, while the nervous tissue isoform has been characterised in some detail, less is known about the mesenchymal isoform. Although its tissue localisation suggests a role in tumour development, neither its cellular origin nor its exact function are known. In this study we demonstrate hyaluronectin synthesis in fibroblasts and smooth muscle cells in vitro. The pattern of immunolocalisation of hyaluronectin in fibroblasts depended on the cell type, length of time spent by the cells in culture and cell density. Immunoreactivity in sparsely plated migratory cells was seen mainly in a patchy distribution at the attached cell surface and in the migration tracks left by the cells on the subtratum. In stationary cells a more uniform distribution associated with the attached cell surface was observed, while in confluent cultures hyaluronectin immunoreactivity was mainly seen as a network of fibrillar material above the cell. The pattern of staining was distinct from that of other hyaluronan-binding proteins. Immunoprecipitation, using antihyaluronectin antibodies, of the substratum-attached material deposited by human fetal fibroblasts revealed a family of proteins ranging from 22 to 90 kDa, the major protein being of approximately 60 kDa. These results lead us to propose that hyaluronectin plays an important role in cell migration, probably by regulation of hyaluronan distribution and binding.

The role of hyaluronan in tumour neovascularization (review).

Tumour growth and metastasis are totally dependant upon neovascularization. The target cell for tumour neovascularization is the blood-vessel endothelial cell, and specific angiogenic molecules produced or induced by the tumour are believed to initiate the process. In this report, we review one of these angiogenic molecules, the glycosaminoglycan hyaluronan (HA), which appears to have differing roles in neovascularization depending on its molecular mass. High-molecular-mass HA is anti-angiogenic whereas oligosaccharides of HA, of specific size, actively stimulate endothelial-cell proliferation and migration, 2 of the key events associated with neovascularization, and induce angiogenesis in vivo. We provide details of the action of HA oligosaccharides on endothelial cells, from binding to cell-surface receptors, through activation of signal transduction pathways and gene expression to protein synthesis, cell proliferation and cell migration. We also suggest a model to account for HA of differing molecular mass being present, at different locations, within a single tumour and how this HA aids both general tumour growth and tumour metastasis.

Isolation and characterisation of a hyaluronan binding protein, hyaluronectin, from human placenta and its colocalisation with hyaluronan.

Hyaluronan (HA) is a major component of the extracellular matrix and is known to influence cell behaviour and to play a role in angiogenesis, morphogenesis and tissue remodelling, although little is known concerning the regulation of these effects. Until now its detection in the placenta has been by indirect methods, which has led to conflicting conclusions as to its distribution and hence its role. Hyaluronectin (HN) is one of a group of proteins with HA binding ability which may regulate the effects of HA. Although nervous tissue HN has been partly characterised with regard to its distribution, structure and biochemistry, little is known about the mesenchymal isoform and its distribution in placenta has not previously been reported. Using specific probes we have characterised the distribution of HA and HN in human placental tissue. At all stages of development studied (8, 10, 12, 30 and 38 wk gestation) HA and HN were unequivocally colocalised, being distributed in the extracellular matrix of stromal tissue of placental villi, chorioallantoic membranes and umbilical cord. Particularly strong immunoreactivity was observed in the villous stroma immediately adjacent to fibrinoid depositions at sites of denudation of the trophoblast layer. Extraction and characterisation of the HN from placental villi have revealed 4 major glycoproteins of 47, 52, 57 and 67 kDa, this being a different pattern and smaller molecular range than observed for the nervous tissue form. This is the first direct demonstration of the presence of HA and HN in the placenta and identifies an abundant new source of mesenchymal HN. The functions of mesenchymal HN are unknown but may include ion exchange, immunosuppression and regulation of the effects of HA in such roles as maintenance of tissue architecture, cell migration and angiogenesis.

Defining the myofibroblast: normal tissues, with special reference to the stromal cells of Wharton's jelly in human umbilical cord.

Cells differing widely in tissue distribution, immunophenotype and ultrastructure have been described as myofibroblasts. The definition of the myofibroblast was analysed as applied to normal tissues, with original observations on Wharton's jelly stromal cells as an example. Stromal cells in Wharton's jelly were studied by conventional histology, immunohistochemistry, and electron microscopy. The normal architecture of the cord was confirmed by light microscopy. Stromal cells and the smooth-muscle cells of the umbilical vessels were positive for vimentin, desmin and alpha-smooth muscle actin, while only the stromal cells were positive for prolyl 4-hydroxylase. Electron microscopy revealed variable but sometimes only moderate amounts of rough endoplasmic reticulum, bundles of smooth-muscle type filaments with focal densities, a large Golgi apparatus with collagen secretion granules, lipid and glycogen. There was no convincing evidence for either lamina or fibronexus junctions. The nature of the stromal cell was discussed in the light of these findings. It was concluded that a myofibroblastic designation was inappropriate and that these cells had phenotypic similarities to vascular smooth muscle cells. The possibility is proposed that most examples of spindle cells cited in the literature as being myofibroblasts and seen in normal tissues not subjected to trauma or showing pathology may be pericytic or smooth-muscle in nature.

Colocalization of hyaluronan and hyaluronectin in normal and neoplastic breast tissues.

Using specific staining methods, we have studied the distribution of hyaluronan (HA) and one of its binding proteins, hyaluronectin (HN), in 19 human breast carcinomas. These two constituents of the extracellular matrix were apparently co-localized in all tissues studied. The level of both was observed to be increased in neoplastic compared to normal tissues. Although no correlation was found between the degree or pattern of staining and the structural differentiation of the epithelial component of the tumours, increased staining was found in areas of tumour invasion, in particular in the connective tissue immediately adjacent to the invading epithelial cell islands.

Prognostic relevance of serum hyaluronan levels in patients with breast cancer.

The serum hyaluronan (HA) level of 238 women with breast cancer was measured by means of a specific radiometric assay. The results show no significant increase in serum HA when compared to levels in 120 control sera. A number of prognostic factors were evaluated including stage of disease, lymph-node involvement, tumour size, histology and presence of oestrogen and progesterone receptors in the tumour. No correlation was found with serum HA concentration and we conclude that serum HA level is of no prognostic significance in breast cancer.

Sera of children with renal tumours contain low-molecular-mass hyaluronic acid.

The molecular mass of hyaluronic acid (HA) rather than its serum concentration alone may be a hallmark of certain types of malignancy. A radiometric assay was used to measure HA levels in 35 children with renal tumours [33 Wilms' tumours and 2 bone metastasizing renal tumours of childhood (BMRTC)] and 20 normal siblings of children with cancer. The HA level in the sera of normal children was barely detectable and had a molecular mass of 1-5 x 10(5). In both Wilms' and BMRTC patients, very high levels of HA were found in preoperative serum samples; these fell dramatically following surgical excision of the tumours. A novel finding of our study was the presence of low-molecular-mass HA (similar to the angiogenic fragments of HA) in the sera of BMRTC patients. In contrast, high-molecular-mass HA (which is not angiogenic) was found in the sera of Wilms' patients (2 x 10(6) kDa). Following surgery in BMRTC patients, not only did serum HA levels fall to a value within normal ranges, but also the HA which remained was of high molecular mass.

Factors Affecting Death of Yeast by Sulfur Dioxide 1.

The interrelated factors that influence the effectiveness of SO2 as a preservative against yeast were studied and the correct quantitative relationships of SO2 molecular species determined. Widely differing pK values for SO2 were found in the literature, compared with experimental data, and one set of values was selected. Undissociated H2SO3 is the only effective form of SO2 against yeast and can be calculated from measurement of free SO2 and pH, and the correct dissociation constants. Duration of contact, pH, concentration of SO2 and yeast, and binding of SO2 all influence the preservative action of SO2. Lower total SO2 concentrations can be used for food preservation by optimum control of these factors.