Effects of phenol on barrier function of a human intestinal epithelial cell line correlate with altered tight junction protein localization

Phenol contamination of soil and water has raised concerns among people living near phenol-producing factories and hazardous waste sites containing the chemical. Phenol, particularly in high concentrations, is an irritating and corrosive substance, making mucosal membranes targets of toxicity in humans. However, few data on the effects of phenol after oral exposure exist.We used an in vitro model employing human intestinal epithelial cells (SK-CO15) cultured on permeable supports to examine effects of phenol on epithelial barrier function. We hypothesized that phenol disrupts epithelial barrier by altering tight junction (TJ) protein expression. The dose-response effect of phenol on epithelial barrier function was determined using transepithelial electrical resistance (TER) and FITC-dextran permeability measurements. We studied phenol-induced changes in cell morphology and expression of several tight junction proteins by immunofluorescence and Western blot analysis. Effects on cell viability were assessed by MTT, Trypan blue, propidium iodide and TUNEL staining.Exposure to phenol resulted in decreased TER and increased paracellular flux of FITC-dextran in a dose-dependent manner. Delocalization of claudin-1 and ZO-1 from TJs to cytosol correlated with the observed increase in permeability after phenol treatment. Additionally, the decrease in TER correlated with changes in the distribution of a membrane raft marker, suggesting phenol-mediated effects on membrane fluidity. Such observations were independent of effects of phenol on cell viability as enhanced permeability occurred at doses of phenol that did not cause cell death. Overall, these findings suggest that phenol may affect transiently the lipid bilayer of the cell membrane, thus destabilizing TJ-containing microdomains.     

Alterations in Epithelial and Mesenchymal Intestinal Gene Expression During Doxorubicin-Induced Mucositis in Mice

In the current study we aimed to gain insight into epithelial-mesenchymal cross-talk and progenitor compartment modulation during doxorubicin (DOX)-induced mucositis in mice. Intestinal segments were collected on various days after DOX treatment. DOX-induced damage at day 1–2 was characterized by increased epithelial proliferation and apoptosis and a decrease in the expression of epithelial differentiation markers. Concurrently, T-cell factor-4 (TCF4) levels increased and the epithelial differentiation enhancing factor, bone morphogenic protein-4 (BMP4), decreased. During severe damage (day 3), BMP4 levels were significantly increased, which inversely correlated with epithelial proliferation. At the same time, the expression of the epithelial differentiation markers was increasing again. At day 7, BMP4 levels were down-regulated, while the levels of the epithelial differentiation markers and TCF4 were normalized again. These data suggest that in response to DOX-induced damage, BMP4 and TCF4 are modulated in such a way that homeostasis of the progenitor compartment is partly preserved.     

An infection with linezolid-resistant S. aureus in a patient with left ventricular assist system

We report an infection with a linezolid-resistant S. aureus in a patient with a left ventricular assist system. Linezolid should be used with caution when invasive devices or foreign materials are in place or therapeutic courses last longer than 14 d. Previous cases of linezolid-resistant S. aureus are summarized.     

Increased augmentation index in rheumatoid arthritis and its relationship to coronary artery atherosclerosis

OBJECTIVE: Arterial stiffness, assessed by the augmentation index and pulse wave velocity, is an independent risk factor for cardiovascular disease. Rheumatoid arthritis (RA) is associated with accelerated atherosclerosis and increased cardiovascular mortality. We examined the hypothesis that augmentation index and pulse wave velocity are increased in RA, and are related to coronary artery atherosclerosis. METHODS: We measured augmentation index and brachial pulse wave velocity in 117 patients with RA [57 with early (< 6 yrs) and 60 with late disease (> 10 yrs)] and 65 healthy controls. Coronary artery calcification was measured by electron beam computed tomography. Augmentation index and pulse wave velocity were compared in patients with early RA, late RA, and controls, and the association with coronary atherosclerosis was examined. RESULTS: Patients with late RA had a higher augmentation index (median 33.8%, interquartile range 27.5% 37.0%) than those with early disease (median 27.5%, IQR 21.0% 34.0%) (p = 0.008) and controls (median 27.0%, IQR 20.4% 33.0%) (p < 0.001). After adjusting for height and cardiovascular risk factors, the association between late disease and augmentation index remained significant (p = 0.02). Augmentation index was associated with coronary calcification score (rs = 0.19, p = 0.046), and the association was marginal after adjustment for cardiovascular risk factors, disease status, and disease activity (p = 0.09). There was no significant difference in brachial pulse wave velocity among patients with late (9.2 +/- 1.7 m/s) and early RA (9.1 +/- 1.6 m/s) and controls (8.9 +/- 1.5 m/s) (p = 0.78). CONCLUSION: Patients with RA have increased augmentation index independent of cardiovascular risk factors. Augmentation index was associated with coronary artery calcification in patients with RA; this was attenuated after adjusting for cardiovascular risk factors.     

Inflammatory mechanisms affecting the lipid profile in patients with systemic lupus erythematosus

OBJECTIVE: Increased low density lipoprotein (LDL) cholesterol and triglycerides, and decreased high density lipoprotein (HDL) cholesterol concentrations are associated with adverse cardiovascular risk in the general population. Patients with systemic lupus erythematosus (SLE) have an altered lipid profile characterized by increased triglycerides and decreased HDL cholesterol concentrations. We examined the relationships between lipid concentrations, cytokines, and inflammatory markers in patients with SLE. METHODS: Fasting lipid concentrations, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were measured in 110 patients with SLE. Disease activity was quantified by the SLE Disease Activity Index (SLEDAI), and disease damage by the Systemic Lupus International Collaborating Clinics (SLICC) score. Concentrations of circulating tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), and insulin were measured and insulin sensitivity calculated. RESULTS: Lower concentrations of HDL cholesterol were independently associated with higher ESR (p < 0.001), IL-6 (p = 0.02), SLEDAI (p = 0.04), and TNF-alpha (p = 0.04) after adjustment for age, sex, race, body mass index, insulin sensitivity, and current use of corticosteroids or hydroxychloroquine. Triglyceride concentrations were associated with higher CRP concentrations (p = 0.02) and SLICC score (p = 0.04). CONCLUSION: Deleterious changes in lipid profile are independently associated with higher concentrations of markers and mediators of inflammation and disease activity and damage in patients with SLE.     

Insulin-induced GLUT4 translocation to the plasma membrane is blunted in large compared with small primary fat cells isolated from the same individual

Aims/hypothesis Several studies have suggested that large fat cells are less responsive to insulin than small fat cells. However, in these studies, large fat cells from obese individuals were compared with smaller fat cells from leaner participants, in effect making it impossible to draw conclusions about whether there is a causal relationship between fat cell size and insulin sensitivity. We hypothesised that small fat cells might be more insulin-responsive than large adipocytes when obtained from the same individual. Materials and methods We developed a method of sorting isolated primary human fat cells by using nylon filters of two different pore sizes. The cells were stained to visualise DNA, which allowed discrimination from artefacts such as lipid droplets. The sorted cells were left to recover overnight, since we had previously demonstrated that this is necessary for correct assessment of insulin response. Results We found similar amounts of the insulin receptor (IR), IRS-1 and GLUT4 when we compared small and large adipocytes from the same volunteer by immunoblotting experiments using the same total cell volume from both cell populations. Activation of IR, IRS-1 and Akt1 (also known as protein kinase B) by insulin was similar in the two cell populations. However, immunofluorescence confocal microscopy of plasma membrane sheets did not reveal any increase in the amount of GLUT4 in the plasma membrane following insulin stimulation in the large fat cells, whereas we saw a twofold increase in the amount of GLUT4 in the small fat cells. Conclusions/interpretation Our results support a causal relationship between the accumulation of large fat cells in obese individuals and reduced insulin responsiveness.     

Reliability and validity of the evaluation to sign consent measure

PURPOSE: The purpose of this report is to evaluate the reliability and validity of the five-item Evaluation to Sign Consent (ESC), a measure that can guide determination of an older adult's capacity to consent for research. DESIGN AND METHODS: Information was obtained from 346 nursing home residents from six facilities who were being enrolled into a randomized controlled trial testing a restorative care intervention. In addition to the ESC, the resident's cognitive status and demographic information was obtained. RESULTS: The average age of the participants was 86.1 +/- 7.3 years; most of the participants were female (84%) and Caucasian (95%). The mean Mini-Mental State Exam score was 18.0 +/- 7.4. A total of 218 residents (63%) did not pass the ESC. According to a Rasch analysis and the inter-rater reliability (r =.81), there was some evidence of reliability and validity with this measure. Logistic regression showed that Items 1 (describing two risks to participation in the study) and 2 (knowing what is associated with participation) had the greatest overall percentage of agreement with the full ESC, and the Mini-Mental State Exam was the only resident-tested variable to predict the results of the ESC. IMPLICATIONS: This study provides useful information about the ESC. It indicates a reason and a method to move beyond cognitive testing that can more appropriately evaluate the capacity to consent to participate in research.