Vasoactive intestinal peptide ameliorates intestinal barrier disruption associated with Citrobacter rodentium-induced colitis

Attaching and effacing bacterial pathogens attach to the apical surface of epithelial cells and disrupt epithelial barrier function, increasing permeability and allowing luminal contents access to the underlying milieu. Previous in vitro studies demonstrated that the neuropeptide vasoactive intestinal peptide (VIP) regulates epithelial paracellular permeability, and the high concentrations and close proximity of VIP-containing nerve fibers to intestinal epithelial cells would support such a function in vivo. The aim of this study was to examine whether VIP treatment modulated Citrobacter rodentium-induced disruption of intestinal barrier integrity and to identify potential mechanisms of action. Administration of VIP had no effect on bacterial attachment although histopathological scoring demonstrated a VIP-induced amelioration of colitis-induced epithelial damage compared with controls. VIP treatment prevented the infection-induced increase in mannitol flux a measure of paracellular permeability, resulting in levels similar to control mice, and immunohistochemical studies demonstrated that VIP prevented the translocation of tight junction proteins: zonula occludens-1, occludin, and claudin-3. Enteropathogenic Escherichia coli (EPEC) infection of Caco-2 monolayers confirmed a protective role for VIP on epithelial barrier function. VIP prevented EPEC-induced increase in long myosin light chain kinase (MLCK) expression and myosin light chain phosphorylation (p-MLC). Furthermore, MLCK inhibition significantly attenuated bacterial-induced epithelial damage both in vivo and in vitro. In conclusion, our results indicate that VIP protects the colonic epithelial barrier by minimizing bacterial-induced redistribution of tight junction proteins in part through actions on MLCK and MLC phosphorylation.

Coalescence and splitting of confined droplets at microfluidic junctions

The ability to merge two droplets is an important component of droplet-based lab-on-a-chip devices, yet flow-induced coalescence is difficult to achieve due to long film drainage times compared with relatively short residence times. We examine droplet collisions at a simple microfluidic T-junction and characterize the response for a wide range of droplet sizes and speeds. We find that three primary responses occur, where coalescence occurs easily at low collision speeds, smaller droplets traveling faster slip past one another without coalescing, and larger and faster droplets can break one another into multiple segments. The critical capillary number for coalescence agrees well with previously reported scaling for isolated droplet pairs when local curvature and speed are taken into account. The critical capillary number for splitting of droplets agrees well with a previously reported stability condition for individual droplets stretching in an extensional flow. Quantifying the necessary conditions for coalescence and non-coalescence behavior should enable the informed design of lab on chip devices based on discrete liquid segments.

Redistribution of suprathermal electrons due to fishbone frequency jumps

MHD instabilities driven by fast electrons identified as fishbonelike modes have been detected on Tore Supra during lower hybrid current drive discharges. Direct experimental evidence is reported of a novel feature: the regular redistribution of suprathermal electrons toward external tokamak regions which are correlated to periodic mode frequency jumps. Sharp drops of the electron temperature time trace are factually linked to the cyclical deterioration of the fast electron confinement.

Marijuana use in potential liver transplant candidates

Concern exists that liver transplant center substance abuse policies may have an inappropriate and disproportionate impact on marijuana users. Our hypothesis is that patients with chronic liver disease who were marijuana users will have inferior survival. This is a retrospective (1999-2007) cohort study. The primary outcome measure is time-dependent, adjusted patient survival from the time of liver transplant evaluation. The primary exposure variable is a positive cannabinoid toxicology screen during the liver transplant evaluation period. Overall, 155 patients qualified as marijuana users while 1334 patients were marijuana non-users. Marijuana users were significantly (p < 0.05) younger (48.3 vs. 52.1), more likely to be male (78.1% vs. 63.0%), have hepatitis C (63.9% vs. 40.6%) and were less likely to receive a transplant (21.8% vs. 14.8%). Marijuana users were more likely to use tobacco, narcotics, benzodiazepines, amphetamines, cocaine or barbiturates (p < 0.05). Unadjusted survival rates were similar between cohorts. Upon multivariate analysis, MELD score, hepatitis C and transplantation were significantly associated with survival, while marijuana use was not (HR 1.09, 95% CI 0.78-1.54). We conclude that patients who did and did not use marijuana had similar survival rates. Current substance abuse policies do not seen to systematically expose marijuana users to additional risk of mortality.

A qualitative assessment of non-carious cervical lesions in extracted human teeth

BACKGROUND

Opinions vary about the causes of non-carious cervical lesions (NCCLs). They have been attributed to toothbrush abrasion, acid corrosion (commonly termed dental erosion), and abfraction. The purpose of this study was to examine the microwear details of NCCLs in a collection of extracted human teeth using scanning election microscopy (SEM).

METHODS

Negative replicas of large NCCLs in 24 extracted human teeth were obtained in polyvinylsiloxane impression material (Light Body Imprint II, 3M ESPE) and viewed under SEM.

RESULTS

All NCCLs extended from the cemento-enamel junction to the root surface and they displayed a variety of wedge-shaped appearances. There was evidence of both abrasion and corrosion in 18 of the 24 teeth (75.0 per cent), abrasion only in one tooth (4.2 per cent) and corrosion only in five teeth (20.8 per cent). Horizontal furrows with smooth edges and minor scratch marks, characteristic of abrasion and corrosion, were noted in 13 teeth (54.2 per cent).

CONCLUSIONS

Based on microscopic assessment of a sample of extracted teeth, it appears that abrasion and corrosion are common associated aetiological factors in the formation of NCCLs.

Reactivity profile of anti-factor VIII antibodies with designed synthetic peptides mimicking epitopes of the C2 and a1 domains

Antibodies (Abs) that block factor VIII (FVIII) activity occur in hemophilia A patients treated with FVIII replacement therapy and severely impair treatment. In this work, we designed and synthesized ten peptides whose sequences are found in putative epitopes at the surface of a1 and C2 domains of the FVIII molecule. These peptides were screened for their ability to inhibit the binding of anti-FVIII Abs from plasmas of hemophilia A patients to FVIII. All peptides were efficient in inhibiting anti-FVIII Abs in plasma from patients with inhibitors, with however different efficiencies. It was found that each tested patient's plasma had a different profile of reactivity with peptides, consistent with an individual anti-FVIII Ab specificity. The profile of recognized peptides was also changing during the treatment of the patients. Three peptides were used in an affinity chromatography assay to attempt to remove anti-FVIII Abs from patients' plasma. Anti-FVIII IgGs were significantly captured by the peptide-Sepharose affinity matrixes as assessed by enzyme-linked immunosorbent assay. However, due to the low level of Abs in the plasma samples, other methods (Chromogenic and Bethesda assays) were not sensitive enough to properly detect the reduction of inhibitors.

Markers of exposure to spotted fever rickettsiae in patients with chronic illness, including fatigue, in two Australian populations

BACKGROUND

Some investigators believe that a proportion of chronically unwell patients, many with fatigue, have an underlying rickettsial disease.

AIM

To investigate the prevalence of markers of rickettsial infection in patients with chronic illnesses.

DESIGN

Observational study.

METHODS

A 526 patient cohort with chronic illnesses from Melbourne, Australia and 400 control patients from Newcastle, Australia were assessed using serology, culture and PCR for the detection of rickettsiae. Rickettsial serology was performed on another cohort of 581 chronically unwell patients (and 34 non-fatigued patients from the same practice) from Adelaide, Australia.

RESULTS

Of the Melbourne patient cohort, 14/526 (3%) were real-time PCR positive for rickettsial DNA compared to none of the 400 control patients (P < 0.001). Of these 14 patients, Rickettsia honei strain 'marmionii' was detected in 5 and isolated from 2. Rickettsaemia was seasonal, with more in winter (8/145; P < 0.03) and less in spring (0/143; P < 0.03). Positive rickettsial serology titres of >or=1:256 were seen in 206 (39%) patients. Of the Adelaide patient cohort, 238/581 (41%) had positive rickettsial antibodies titres. Of the 34 control sera, 5 (15%) were serologically positive (P < 0.002). Both Melbourne and Adelaide patient cohorts had significantly higher seropositivity than the Newcastle control cohort (3/399; P < 0.0001).

CONCLUSION

In patients with chronic illness, rickettsial DNA in peripheral blood and/or rickettsial seropositivity may represent exposure to rickettsiae or underlying rickettsial diseases. It is not known whether the presence of rickettsiae is causally related to the patients' chronic illnesses, or reactivation of a latent rickettsial infection.

Construction and validation of a patient-reported outcome dedicated to chronic venous disorders: SQOR-V (specific quality of life and outcome response - venous)

BACKGROUND

Chronic venous disorders (CVD) have an impact on quality of life (QoL), both physically and psychologically. As of now, several vein specific QoL scales exist, but no patient-reported outcome (PRO) is available which takes into account altogether symptoms, impairment of activities, appearance of the legs and concerns regarding health risk. Since clinical severity and disability are mostly evaluated in severe patients, where the main outcome - namely skin changes - is obvious but rare, the authors considered that a reproducible and clinically relevant survey that could account for specific patients' complaints was needed, particularly for CEAP C0s-C3 patients.

OBJECTIVES

The objective of this study was to build a specific autoquestionnaire and to establish its statistical validity and clinical relevance.

METHODS

A review of existing questionnaires and an analysis of relevant literature were carried out by a committee of experts. The committee then developed a questionnaire of 46 items, with special attention to relevance for venous disorders and patients' main complaints. After construction, the French version was field-tested and results statistically analyzed. In the specific QoL & Outcome Response - Venous (SQOR-V), each item is given a value by the patient and items are grouped in five dimensions. Each dimension is weighed to a maximum value of 20, yielding an overall maximum score of 100.

RESULTS

Two hundred and two questionnaires were analyzed for the initial evaluation and 152 at a second (test-retest). Determination of the Cronbach's alpha coefficient (0.96) and structural analysis demonstrated an excellent internal and structural coherence. Test-retest comparisons confirmed good reproducibility. Comparison with SF-12 and CED-D questionnaires and with CEAP classification groups verified both structural and clinical validity.

CONCLUSIONS

This study demonstrates QoL impairment in patients suffering from chronic venous disorders (CVD). It also verifies the statistical validity of the SQOR-V questionnaire. More studies are needed to demonstrate the improvement in specificity and accuracy this questionnaire provides compared to existing vein-specific QoL scales, and to determine its ability to assess efficacy of any kind of treatment at any stage of the disease. Provided adequate acknowledgment of its authors, the use of SQOR-V is free. An English version is available, currently pending validation.

Atopic Dermatitis: Impact on the Quality of Life of Patients and Their Partners

BACKGROUND

The impact of atopic dermatitis (AD) on the patient's quality of life is relatively well known. However, the influence on the patient's spouse has never been studied.

OBJECTIVE

To evaluate the impact of AD on the quality of life, sleeping and sexual life of patients and their partners.

METHODS

In this cross-sectional study, patients and their partners completed a number of questionnaires asking about their general health and their quality of life [Short Form 12, Epworth, Dermatology Life Quality Index (DLQI)] and completed an idiosyncratic measure asking about their sexual functioning. AD severity was clinician rated using Scoring atopic dermatitis (SCORAD).

RESULTS

A total of 266 patients were included. The mean DLQI score was 8.8. The physical and mental composite 12 scores were 50.7 and 39.5, respectively. These 3 scores were significantly related to SCORAD. A decrease in sexual desire due to AD was noted in 57.5% of patients. The quality of life of partners did not appear to be particularly impaired, but 36.5% reported that the appearance of eczema had an impact on their sex life.

CONCLUSION

The influence of AD on sex life is significant both for the patients and their partners.

[Long-term management of post acute coronary syndrome with oral antiplatelet therapy]

Cardiovascular disease is the primary cause of early death and morbidity in the industrialized world and is becoming a growing problem in many developing countries. Coagulation inhibitors play a major role in the management of the acute phase of ACS whether in association with reperfusion strategies or not. Currently, and in accordance with the results of major randomised studies, for medium and long-term management, the association of Clopidogrel and aspirin is the treatment of choice. However, despite the recognised benefits of this therapeutic strategy and above all the recommendations of learned societies, which have placed this bi-therapy in class I, according to national and international registries it is still underused. Moreover, all of these registries have confirmed, in the real world, the negative impact of not prescribing this antiplatelet therapy on morbidity and mortality after both ST and non-ST elevation acute coronary syndrome. which shows the difficulty of applying to everyday clinical practice the results of major randomised cohorts.

Protease-activated receptor-4: a novel mechanism of inflammatory pain modulation

BACKGROUND AND PURPOSE

Protease-activated receptor-4 (PAR(4)), the most recently discovered member of the PARs family, is activated by thrombin, trypsin and cathepsin G, but can also be selectively activated by small synthetic peptides (PAR(4)-activating peptide, PAR(4)-AP). PAR(4) is considered a potent mediator of platelet activation and inflammation. As both PAR(1) and PAR(2) have been implicated in the modulation of nociceptive mechanisms, we investigated the expression of PAR(4) in sensory neurons and the effects of its selective activation on nociception.

EXPERIMENTAL APPROACH AND KEY RESULTS

We demonstrated the expression of PAR(4) in sensory neurons isolated from rat dorsal root ganglia by reverse transcription-polymerase chain reaction and immunofluorescence. We found that PAR(4) colocalized with calcitonin gene-related peptide and substance P. We also showed that a selective PAR(4)-AP was able to inhibit calcium mobilization evoked by KCl and capsaicin in rat sensory neurons. Moreover, the intraplantar injection of a PAR(4)-AP significantly increased nociceptive threshold in response to thermal and mechanical noxious stimuli, while a PAR(4) inactive control peptide had no effect. The anti-nociceptive effects of the PAR(4)-AP were dose-dependent and occurred at doses below the threshold needed to cause inflammation. Finally, co-injection of the PAR(4)-AP with carrageenan significantly reduced the carrageenan-induced inflammatory hyperalgesia and allodynia, but had no effect on inflammatory parameters such as oedema and granulocyte infiltration.

CONCLUSIONS AND IMPLICATIONS

Taken together, these results identified PAR(4) as a novel potential endogenous analgesic factor, which can modulate nociceptive responses in normal and inflammatory conditions.

Comparison of microshear bond strengths of four self-etching bonding systems to enamel using two test methods

BACKGROUND

Recent advances in enamel and dentine adhesive technology have resulted in the emergence of many new adhesive systems. Self-etching bonding systems do not require a separate etching step and the newest systems are the "all-in-one" systems which combine etching, priming and bonding into a single application. This study reports laboratory enamel microshear bond strengths of a self-etching priming and three all-in-one systems and also evaluates two different microshear bond test methods.

METHODS

One hundred and nineteen enamel specimens were bonded (0.8 mm diameter) with either Clearfil Protect Bond (Kuraray), Xeno III (Dentsply), G Bond (GC) or One-Up Bond F (Tokuyama) using Palfique Estelite resin composite and stored in 37 degrees Celsius water for seven days. The microshear bond test method used either a blade or wire to apply the shear stress. Results were analysed with one-way ANOVA and post hoc (Tukey) multiple comparison analysis.

RESULTS

Clearfil Protect Bond demonstrated higher and more consistent bond strengths than Xeno III, G Bond or One-Up Bond F. The wire method showed much greater reliability in results, with a coefficient of variation half that of the blade method.

CONCLUSIONS

All-in-one adhesives seem to be less reliable than the two-step self-etching priming adhesive when bonding to enamel. Test method can significantly affect results in the microshear bond test method.