Urea hydrogen peroxide determination in whole blood using europium tetracycline probe

We introduce the use of a lanthanide complex, tetracycline-europium, for the clinical diagnosis of urea hydrogen peroxide in human whole blood. The values obtained agree with the urea concentration variation verified in 49 patients, including 12 predialysis, 12 peritoneal, and 15 dialysis subjects, and 10 controls. This method is noninvasive and can help in the identification of renal and cardiac diseases.     

Shear Stress, Temperature, and Inoculation Concentration Influence the Adhesion of Water-Stressed Helicobacter pylori to Stainless Steel 304 and Polypropylene

Although molecular techniques have identified Helicobacter pylori in drinking water-associated biofilms, there is a lack of studies reporting what factors affect the attachment of the bacterium to plumbing materials. Therefore, the adhesion of H. pylori suspended in distilled water to stainless steel 304 (SS304) coupons placed on tissue culture plates subjected to different environmental conditions was monitored. The extent of adhesion was evaluated for different water exposure times, using epifluorescence microscopy to count total cell numbers. High shear stresses—estimated through computational fluid dynamics—negatively influenced the adhesion of H. pylori to the substrata (P < 0.001), a result that was confirmed in similar experiments with polypropylene (P < 0.05). However, the temperature and inoculation concentration appeared to have no effect on adhesion (P> 0.05). After 2 hours, H. pylori cells appeared to be isolated on the surface of SS304 and were able to form small aggregates with longer exposure times. However, the formation of a three-dimensional structure was only very rarely observed. This study suggests that the detection of the pathogen in well water described by other authors can be related to the increased ability of H. pylori to integrate into biofilms under conditions of low shear stress. It will also allow a more rational selection of locations to perform molecular or plate culture analysis for the detection of H. pylori in drinking water-associated biofilms.     

The contribution of extensin network formation to rapid, hydrogen peroxide-mediated increases in grapevine callus wall resistance to fungal lytic enzymes

Grapevine (Vitis vinifera cv. Touriga) callus cell walls contain a high level of the monomeric extensin, GvP1. Hydrogen peroxide stimulus of these cultures causes the rapid loss of monomeric GvP1, concomitant with marked increases in insoluble GvP1 amino acids and wall resistance to digestion by fungal lytic enzymes. JIM11 immunolocalization studies indicated that monomeric and network GvP1 were evenly distributed in the callus cell wall. These primary cell walls were used to investigate the specific contribution of extensin and other ionically bound cell-wall proteins to hydrogen peroxide-mediated increases in resistance to fungal lytic enzymes. This was performed by removing ionically-bound proteins and assaying for hydrogen peroxide-enhanced resistance after the addition of selected protein fractions. The results indicate that hydrogen peroxide-induced increases in resistance to digestion by fungal lytic enzymes require a co-operative action between network extensin formation and the electrostatic interaction of additional wall proteins with the extracellular matrix.     

Clinical and molecular genetic features of ARC syndrome

Arthrogryposis, renal dysfunction and cholestasis (ARC) syndrome (MIM 208085) is an autosomal recessive multisystem disorder that may be associated with germline VPS33B mutations. VPS33B is involved in regulation of vesicular membrane fusion by interacting with SNARE proteins, and evidence of abnormal polarised membrane protein trafficking has been reported in ARC patients. We characterised clinical and molecular features of ARC syndrome in order to identify potential genotype-phenotype correlations. The clinical phenotype of 62 ARC syndrome patients was analysed. In addition to classical features described previously, all patients had severe failure to thrive, which was not adequately explained by the degree of liver disease and 10% had structural cardiac defects. Almost half of the patients who underwent diagnostic organ biopsy (7/16) developed life-threatening haemorrhage. We found that most patients (9/11) who suffered severe haemorrhage (7 post biopsy and 4 spontaneous) had normal platelet count and morphology. Germline VPS33B mutations were detected in 28/35 families (48/62 individuals) with ARC syndrome. Several mutations were restricted to specific ethnic groups. Thus p.Arg438X mutation was common in the UK Pakistani families and haplotyping was consistent with a founder mutation with the most recent common ancestor 900–1,000 years ago. Heterozygosity was found in the VPS33B locus in some cases of ARC providing the first evidence of a possible second ARC syndrome gene. In conclusion we state that molecular diagnosis is possible for most children in whom ARC syndrome is suspected and VPS33B mutation analysis should replace organ biopsy as a first line diagnostic test for ARC syndrome.     

Self-reported oral hygiene habits among institutionalised elderly and their relationship to the condition of oral tissues in Taubaté, Brazil

Objectives: To record self‐reported hygiene habits, examine the oral conditions of a sample group of institutionalised elderly, and examine possible relationships between these habits and conditions. Design: Cross‐sectional. Setting: All the institutions for the elderly in Taubaté, Brazil. Subjects: The entire population of these institutionalised elderly people (n = 553). Intervention: The subjects were interviewed and underwent an oral examination. Main outcome measures: Oral hygiene habits, oral conditions and statistical relationships between habits and oral conditions were recorded. Results: The average age of the subjects who knew their age (n = 364) was 74.9 years (±12.9), and 64.7% of the sample group were females. Denture‐related stomatitis was found in 19.5%, impaired manual dexterity in 40%, dry mouth sensation in 36.3%, difficulty in performing oral hygiene in 20%, no oral hygiene‐related orientation in 54.1%, no periodic oral examinations in 59.5%, and no tongue cleaning in 68.3% was declared. Among dentate subjects, 73.3% had periodontal disease, 54.7% had caries, 26% reported no toothbrushing, and 7.3% reported flossing. Of the denture wearers, 7% did not brush their dentures. Denture‐related stomatitis showed a statistical relationship with impaired manual dexterity (p = 0.012) and an inverse statistical relationship with denture brushing frequency (p = 0.006). Periodontal disease showed an inverse relationship to flossing (p < 0.001) and tongue cleaning (p = 0.0026). Caries showed an inverse relationship with tooth‐brushing (p = 0.043), flossing (0.022), proper oral hygiene orientation (p = 0.041) and periodical check‐ups (p = 0.007). Conclusion: Oral hygiene practices in this sample group were found to be inadequate, and statistically significant relationships were verified between the lack of good oral hygiene practices and the deleterious oral conditions.     

Electron-transfer mechanism of the triplet state quenching of aluminium tetrasulfonated phthalocyanine by cytochrome c

The mechanism of electron-transfer from aluminium tetrasulfonated phthalocyanine triplet state to cytochrome c was investigated in this work. This reaction successfully quenches the dye triplet state due to the formation of complexes between the solute and the protein at the active site. The electron-transfer rate constant is around 3x10(7) s(-1), and is in accordance with previous results for the singlet excited state quenching [C.A.T. Laia, S.M.B. Costa, D. Phillips, A. Beeby. Electron-transfer kinetics in sulfonated aluminum phthalocyanines/cytochrome c complexes, J. Phys. Chem. B 108 (2004) 7506-7514.] in the framework of the Marcus theory, with a reorganization energy equal to 0.94 eV. The complex formation is diffusion controlled, but heterogeneities of the protein surface charge distribution lead to quenching rate constants smaller than predicted on a hard-spheres model with electrostatic interactions. Also the binding equilibrium constant is strongly affected by this phenomenon. Ionic strength plays an important role on the complex formation, but its effect on the unimolecular electron-transfer rate constant is negligible within experimental error.     

Synthetic amides toxic to the leaf-cutting ant Atta sexdens rubropilosa L. and its symbiotic fungus

• 1 Nine synthetic amides similar to natural N‐piperidine‐3‐(4,5‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N‐pyrrolidine‐3‐(4,5‐methylenedyoxiphenyl)‐2‐(E)‐propenamide were synthesized and identified by their spectroscopic data.
• 2 The toxicity of these synthetic amides to the Atta sexdens rubropilosa workers and the antifungal activity against Leucoagaricus gongylophorus, the symbiotic fungus of the leaf‐cutting ants, were determined.
• 3 Workers ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls for N‐pyrrolidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N‐benzyl‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at a concentration of 100 µg/mL.
• 4 The completely inhibition (100%) of the fungal growth was observed with N‐piperidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N,N‐diethyl‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at concentrations of 50 and 100 µg/mL and N‐pirrolidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at a concentration of 100 µg/mL.
• 5 The possibility of controlling these insects in the future using synthetic piperamides that can simultaneously target both organisms is discussed.

     

Small molecule inhibitors of lysozyme amyloid aggregation

Protein amyloid aggregation is associated with a number of important human pathologies, but the precise mechanisms underlying the toxicity of amyloid aggregates are still incompletely understood. In this context, drugs capable of blocking or interfering with the aggregation of amyloidogenic proteins should be considered in strategies aimed at the development of novel therapeutic agents. Human lysozyme variants have been shown to form massive amyloid deposits in the livers and kidneys of individuals affected by hereditary systemic amyloidosis. Currently, there are no clinical treatments available to prevent or reverse formation of such amyloid deposits. We have recently described a number of di- and trisubstituted aromatic compounds that block the formation of soluble oligomers and amyloid fibrils of the β-amyloid peptide (Aβ) and protect hippocampal neurons in culture from Aβ-induced toxicity. Here, we show that some of those compounds inhibit the formation and disrupt preformed amyloid fibrils from both human and hen egg white lysozyme. These results suggest that these small molecule compounds may serve as prototypes for the development of drugs for the prevention or treatment of different types of amyloidoses.     

Dual function of the long pentraxin PTX3 in resistance against pulmonary infection with Klebsiella pneumoniae in transgenic mice

The long pentraxin PTX3 is expressed during acute inflammation and appears to control nitric oxide (NO) and tumor necrosis factor (TNF)-alpha production. In the present study, the physiological function of PTX3 was investigated in a model of pulmonary infection caused by the Gram-negative bacterium Klebsiella pneumoniae. Transgenic mice expressing multiple copies of PTX3 under the control of its own promoter were used to assess lethality rates, bacterial counts and inflammatory indices following pulmonary infection of mice. Expression of PTX3 is enhanced during pulmonary infection in wild-type mice. In transgenic mice given a high inoculum, overt PTX3 expression was associated with faster lethality. Faster lethality correlated with enhanced nitrate in plasma, an inability of neutrophils to migrate to lung tissue and greater dissemination of bacteria to blood at 20h after infection. In contrast, transgenic PTX3 expression conferred protection to mice given lower pulmonary inocula. In the latter experiments, there was enhanced TNF-alpha production, greater neutrophil influx and phagocytosis of bacteria by migrated neutrophils. By controlling the production of TNF-alpha and NO, and depending on the intensity of the inflammatory response induced by a given inoculum, the expression of PTX3 may favor or disfavor the influx of neutrophils and the ability of the murine host to deal with pulmonary infection with K. pneumoniae. These experiments highlight the delicate balance that exists among the various mediators that control the inflammatory response and suggest that PTX3 is an essential part of the ability of a host to deal with bacterial infection.