Hypertonicity regulates the function of human neutrophils by modulating chemoattractant receptor signaling and activating mitogen-activated protein kinase p38

Excessive neutrophil activation causes posttraumatic complications, which may be reduced with hypertonic saline (HS) resuscitation. We tested if this is because of modulated neutrophil function by HS. Clinically relevant hypertonicity (10-25 mM) suppressed degranulation and superoxide formation in response to fMLP and blocked the activation of the mitogen activated protein kinases (MAPK) ERK1/2 and p38, but did not affect Ca2+ mobilization. HS did not suppress oxidative burst in response to phorbol myristate acetate (PMA). This indicates that HS suppresses neutrophil function by intercepting signal pathways upstream of or apart from PKC. HS activated p38 by itself and enhanced degranulation in response to PKC activation. This enhancement was reduced by inhibition of p38 with SB203580, suggesting that p38 up-regulation participates in HS-induced enhancements of degranulation. HS had similar effects on the degranulation of cells that were previously stimulated with fMLP, but had no effect on its own, suggesting that HS enhancement of degranulation requires another signal. We conclude that depending on other stimuli, HS can suppress neutrophil activation by intercepting multiple receptor signals or augment degranulation by enhancing p38 signaling. In patients HS resuscitation may reduce posttraumatic complications by preventing neutrophil activation via chemotactic factors released during reperfusion.     

Proton spectroscopy in myotonic dystrophy: correlations with CTG repeats

We have previously reported inhibition of cell-free activation of the neutrophil superoxide-generating NADPH oxidase by a soluble cationic protein of neutrophil granules and by low concentrations of human defensin. Subcellular fractionation carried out in the current study indicated that the inhibitory substance was derived from azurophilic granules, was released into the medium on cell stimulation, and was resistant to phenylmethylsulfonyl fluoride (PMSF). Phorbol ester was the most effective stimulus for the release of the blocking activity. The possibility was raised that granule protein(s) act in vivo as negative modulators of superoxide production. Gel filtration of granule extract revealed a markedly retarded protein peak exhibiting oxidase-blocking activity and containing lysozyme as the main protein. Because lysozyme did not exert inhibitory effects on oxidase activation, association of the inhibitory protein with lysozyme was assumed. Indeed a column of immobilized lysozyme retained a fraction of the granule extract's oxidase-blocking activity. Elution with a low-pH buffer recovered a component capable of inhibition of the NADPH oxidase in stimulated neutrophils and in the cell-free system. The main 29-kDa protein band in the eluted fraction was identified as proteinase 3, a serine protease of azurophilic granules. Enzymatically active as well as PMSF-blocked conventionally purified proteinase 3 interfered with phorbol myristate acetate-induced superoxide release. These findings support the hypothesis that exocytosed granule constituents may prevent excessive activation of the NADPH oxidase.     

Brief assessments of dietary behavior in field settings

Our research team is involved in ongoing research in both worksites and medical office settings. These settings offer great potential for reaching individuals who would not otherwise participate in health promotion, but they also place considerable constraints on assessment time and efforts, especially if one's goal is to attract a high and representative proportion of employees or patients. This paper reports on our experience with measures of dietary behavior in these two settings. We found it problematic to collect detailed assessments such as 4-day food records or comprehensive food frequency/history checklists in worksites or medical office settings using population-based samples. Instead, we recommend and provide data on the utility of a dietary-fat screening instrument, and on the Food Habits Questionnaire (FHQ-Kristal, Shattuck, & Henry, 1990), a brief measure of dietary behaviors associated with high-fat eating patterns. The FHQ, in particular, was found to correlate well with other more costly and time-consuming methods of assessment, to be reliable and responsive to intervention effects, and to provide behavioral targets for intervention. The strengths and limitations of these measures for tailoring intervention and assessing outcomes are discussed.     

Serum concentrations of soluble adhesion molecules in patients with colorectal cancer

The concentrations of the soluble adhesion molecules E-cadherin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were investigated in 48 patients with colorectal cancer before treatment, and their relation to clinical, histological and routine laboratory parameters was examined. Data were collected on tumour stage at presentation, presence and sites of metastatic disease, tumour pathology and results of routine laboratory tests. Serum concentrations of ICAM-1 and VCAM-1 were significantly elevated in the patients with colorectal cancer in comparison with a group of healthy subjects (P < 0.00001). Levels of circulating ICAM-1 and VCAM-1 were increased both in patients with local and those with metastatic disease. Although elevated in some patients soluble E-cadherin and E-selectin concentrations were not significantly elevated compared with the control group (P = 0.71 and P = 0.052 respectively). The levels of circulating ICAM-1 were significantly correlated with those of VCAM-1 and E-selectin. A correlation was also found between the serum concentrations of E-selectin and ICAM-1 and alkaline phosphatase, total white cell count and platelet count. VCAM-1 was positively correlated with age and negatively with degree of tumour differentiation and haemoglobin concentration. The biological implications and possible clinical relevance of these findings are discussed.     

A method to detect variations in the wetting properties of microporous polymer membranes

With the ability to perform dynamic experiments in the environmental scanning electron microscope (ESEM), the evaluation of microporous polymer membranes via a scanning electron microscope has advanced beyond morphological and elemental analysis. By adjusting sample temperature and environmental chamber pressure, the process of condensing water onto the porous membrane surface can be achieved. In doing so, assessments about the uniformity of wetting in hydrophilic membranes can be obtained based on how the liquid water spreads. Variations in the shape of condensed water droplets formed on non-water wetting structures will reflect the degree of hydrophobicity. This technique has proven useful in the characterization of hydrophobic spots on chemically modified hydrophilic structures and the dynamic examination of irregular wetting patterns in naturally hydrophilic membranes.     

Distinct nuclear proteins competing for an overlapping sequence of cyclic adenosine monophosphate and negative regulatory elements regulate tissue-specific mouse renin gene expression

The mouse renin locus (Ren-1d) exhibits specific patterns of tissue expression. It is expressed in kidney but not submandibular gland (SMG). This locus contains a negative regulatory element (NRE) and a cAMP responsive element (CRE) that share an overlapping sequence. In the kidney, CRE binding proteins (CREB) and NRE binding proteins (NREB) compete for binding to this sequence, with the CREB having a greater affinity. In the SMG, CREB is inactivated by an inhibitory protein, permitting NREB to bind to the sequence, thus inhibiting Ren-1d expression. We hypothesize that the competition between NREB and CREB for this sequence governs tissue-specific expression of mouse renin. We speculate that this may be a general paradigm that determines tissue-specific gene expression.     

Functional complementation by electroporation of human BACs into mammalian fibroblast cells

Bacterial Artificial Chromosomes (BACs) have been used to complement a metabolic defect and to transfer a drug resistance marker into mammalian cells by electroporation. The selectable markers are stable and the recipient cells have BAC DNA integrated into the chromosomes as shown by fluorescent in situ hybridization, PCR and Southern hybridization.