High plasma arginine concentrations in critically ill patients suffering from hepatic failure

Objective: In physiological conditions, the liver plays an important role in the regulation of plasma arginine concentrations by taking up large amounts of arginine from the hepatic circulation. When hepatic failure is present, arginine metabolism may be disturbed. Therefore, we hypothesized high arginine plasma concentrations in critically ill patients suffering from hepatic failure. Design: We prospectively collected blood samples from a cross-section of intensive care unit patients. Setting: Surgical intensive care unit of a Dutch university medical center. Subjects: A total of 52 critically ill patients with clinical evidence of dysfunction of more than two organs were recruited. Measurements: Plasma arginine concentrations were determined by HPLC. We identified correlations of arginine concentrations with organ failure scores and laboratory variables by univariate and multiple regression analyses. Results: High plasma arginine concentrations were found in critically ill patients developing organ failure. Patients who were in the highest quartile of plasma arginine concentrations had significantly lower fibrinogen concentrations, higher lactic acid concentrations, and longer prothrombin time. Stepwise multiple regression analysis showed that concentrations of arginine were independently associated with the presence of hepatic failure (P = 0.03) and renal failure (P = 0.048). In addition, lactic acid proved to be an independent determinant of plasma arginine concentration (P = 0.014). Conclusions: Critically ill patients who suffer from hepatic failure have elevated plasma arginine concentrations. Additional arginine in the treatment of these patients can be harmful, and therefore should not be used as a standard nutritional regimen until further evaluation

Strategy for development of site-specific ubiquitin antibodies

Protein ubiquitination is a key post-translational modification regulating a wide range of biological processes. Ubiquitination involves the covalent attachment of the small protein ubiquitin to a lysine of a protein substrate. In addition to its well-established role in protein degradation, protein ubiquitination plays a role in protein-protein interactions, DNA repair, transcriptional regulation, and other cellular functions. Understanding the mechanisms and functional relevance of ubiquitin as a signaling system requires the generation of antibodies or alternative reagents that specifically detect ubiquitin in a site-specific manner. However, in contrast to other post-translational modifications such as acetylation, phosphorylation, and methylation, the instability and size of ubiquitin-76 amino acids-complicate the preparation of suitable antigens and the generation antibodies detecting such site-specific modifications. As a result, the field of ubiquitin research has limited access to specific antibodies. This severely hampers progress in understanding the regulation and function of site-specific ubiquitination in many areas of biology, specifically in epigenetics and cancer. Therefore, there is a high demand for antibodies recognizing site-specific ubiquitin modifications. Here we describe a strategy for the development of site-specific ubiquitin antibodies. Based on a recently developed antibody against site-specific ubiquitination of histone H2B, we provide detailed protocols for chemical synthesis methods for antigen preparation and discuss considerations for screening and quality control experiments.Chemical Immunolog

Essential oils compared to chlorhexidine with respect to plaque and parameters of gingival inflammation: a systematic review

Background: The purpose of this review is to systematically evaluate the effects of an essential-oil mouthwash (EOMW) compared to a chlorhexidine mouthwash with respect to plaque and parameters of gingival inflammation. Methods: PubMed/MEDLINE and Cochrane CENTRAL databases were searched for studies up to and including September 2010 to identify appropriate articles. A comprehensive search was designed, and the articles were independently screened for eligibility by two reviewers. Articles that evaluated the effects of the EOMWcompared to chlorhexidine mouthwashwere included. Where appropriate, a meta-analysis was performed, and weighted mean differences (WMDs) were calculated. Results: A total of 390 unique articles were found, of which 19 articles met the eligibility criteria. A meta-analysis of long-term studies (duration ‡4 weeks) showed that the chlorhexidine mouthwash provided significantly better effects regarding plaque control than EOMW (WMD: 0.19; P = 0.0009). No significant difference with respect to reduction of gingival inflammation was found between EOMW and chlorhexidine mouthwash (WMD: 0.03; P = 0.58). Conclusion: In long-term use, the standardized formulation of EOMWappeared to be a reliable alternative to chlorhexidine mouthwash with respect to parameters of gingival inflammation

The effect of an essential-oils mouthrinse as compared to a vehicle solution on plaque and gingival inflammation: a systematic review and meta-analysis

Objective The purpose of this review was to systematically evaluate the effects of an alcohol vehicle solution (V-Sol) compared with an essential-oils mouthwash (EOMW) and if available with a water-based control (WC) on plaque, gingival inflammation parameters and extrinsic tooth staining. Materials and Methods The PubMed-MEDLINE, Cochrane-CENTRAL and EMBASE databases were searched. Where appropriate, a meta-analysis was performed, and difference of means (DIFFM) as calculated. Results In total, 971 unique papers were found of which five met the eligibility criteria. The DIFFM of the meta-analysis of four 6-month studies showed that the EOMW provided significantly better plaque control (DIFFM = 0.39, P < 0.00001) and gingival inflammation reduction as measured by the Löe and Silness Index (DIFFM = 0.36, P = 0.00001) as compared to the V-Sol. Regarding extrinsic tooth staining, a small but significant difference (DIFFM = −0.08, P = 0.03) was observed. Conclusion Limited data, but with a low risk of bias, were available to assess the potential benefit of the alcohol-containing V-Sol. ‘High’- and ‘moderate’-quality data were available for the analysis of plaque and gingivitis, respectively. Within these limitations, EOMW appears to provide a significant oral health benefit during the 6 months of use. The data retrieved for this review suggest that the essential oils produce an effect on plaque and gingivitis that extends beyond the V-Sol. Furthermore, the V-Sol proved to be no different from a WC

Toothbrush wear in relation to toothbrushing effectiveness

Objective: To investigate to what extent the degree of toothbrush wear of 3-month-old manual toothbrushes influence plaque scores. Material and methods: During a recently published study with a follow-up of 1 year, all participants performed a similar basic home-based oral hygiene regimen. Hence, they were instructed to brush for 2 minutes twice daily according to the Bass method technique and using a standard dentifrice containing sodium fluoride. Toothbrushes were turned in every 3-month, and the degree of wear was scored. The mean plaque score data were additionally analysed and correlated with wear scores of the toothbrushes. Results: For analysis, for each of 172 individual participants, a set of three identical, 3-month-old used toothbrushes were available. Toothbrush wear varied widely between participants. However, per patient, the 3-month wear status of the three evaluated toothbrushes was strongly correlated (rho = 0.8, P < 0.0001). Participants who returned toothbrushes with extreme wear had significantly higher plaque scores than those who returned toothbrushes with no visible or light wear (P = 0.01). Conclusion: Toothbrush wear per individual patient is fairly consistent. Toothbrushes with extreme wear were less effective than those with no or light wear. Therefore, bristle splaying appears to be a more appropriate measure of brush replacement time then the commonly used toothbrush age. Splaying of the outer tufts beyond the base of the toothbrush is a condition that indicates it is time to change the brush