One-sided surface modification of cellulose fabric by printing a modified TEMPO-mediated oxidant.

One-sided surface oxidation of lyocell type cellulose fabric can be achieved by use of a modified TEMPO-mediated oxidation system. A borate-based buffer was used to maintain stable pH conditions and screen printing was applied to achieve oxidation on the fabric surface only. To formulate an applicable procedure, the TEMPO/NaBr/NaOCl system was split into two treatment steps: firstly, the fabric was impregnated with a buffered TEMPO/NaBr solution and dried, then a thickened NaOCl paste was printed on the fabric. FTIR-ATR spectra and methylene blue sorption experiments demonstrated successful modification on the printed side of the fabric. Substantial increases in carboxylic group content and water retention value were observed. The higher concentration of carboxylic groups on the fabric surface also led to a localised increase in binding capacity for Ca(2+)-ions. This new concept permits controlled oxidation of cellulose surfaces by printing techniques.

Ca²+ sorption on regenerated cellulose fibres.

High calcium content in cellulose materials can cause considerable problems in pulp processing, textile chemical treatment and consumer use, e.g. dyeing operations or household laundry. The Ca(2+) binding capacity of cellulose also is of relevance in food and medical applications. Through their carboxyl group content regenerated cellulose fibres can act as weak anion exchangers, thus all types of regenerated cellulose fibres such as lyocell, viscose and modal fibres, show a distinct ability to bind Ca(2+) ions. The binding capacity is limited by the carboxyl group content, which was determined with 15 mmol/kg for lyocell fibres and 20 mmol/kg for viscose fibres, using the Methylene Blue sorption method. The presence of bound Ca(2+) also was demonstrated by complex formation with alizarin. The molar ratio between carboxylic group content and bound Ca(2+) ions was one Ca(2+) ion for a single carboxyl group. As a result of Ca(2+) sorption a positive net charge of the cellulose results and another anion has to be bound as counter ion for reasons of charge neutralisation. Results of potentiometric titrations indicate HCO(3)(-) to be present as counter ion in the Ca(2+) cellulose system. Thus under the experimental conditions studied, bound Ca(2+) is proposed to be present in the form COO(-)Ca(2+)HCO(3)(-).

Helicobacter pylori eradication rates in children upon susceptibility testing based on noninvasive stool polymerase chain reaction versus gastric tissue culture.

BACKGROUND AND OBJECTIVES: In children with clarithromycin-resistant Helicobacter pylori, clarithromycin-containing therapies often fail. The present study aimed to assess the outcome of tailored therapy upon noninvasive versus invasive H pylori susceptibility testing. PATIENTS AND METHODS: A retrospective cohort study was conducted in a pediatric outpatient clinic located in a region where H pylori clarithromycin resistance is highly prevalent. Between June 2007 and September 2009, 96 infected children (mean age 10.8 years), naïve to H pylori eradication treatment, were prescribed triple eradication therapies. These therapies were individually tailored upon susceptibility testing performed either noninvasively using stool polymerase chain reaction (stool PCR group) or invasively using endoscopy, biopsy, and culturing of gastric biopsies (gastric biopsy group). Eradication was defined by negative results upon noninvasive testing including stool PCR at least 5 weeks after the end of treatment. RESULTS: H pylori was eradicated in 43 of 55 stool PCR group versus 30 of 41 gastric biopsy group children (78.2% vs 73.2%, P = 0.63). Of those H pylori strains with pretherapeutic clarithromycin susceptibility, 78.8% were eradicated in the stool PCR group and 69.2% in the gastric biopsy group (P = 0.41) following clarithromycin-containing therapy; clarithromycin resistance was acquired by 4.1% of strains in the former group versus 12% in the latter (P = 0.33). CONCLUSIONS: Stool PCR is as effective as the invasive approach of H pylori susceptibility testing for targeting resistance-guided eradication treatments in children. Furthermore, stool PCR is a useful tool for tracking the emergence of clarithromycin resistance following eradication treatment.

Time trends of Helicobacter pylori resistance to antibiotics in children living in Vienna, Austria.

BACKGROUND: Increase of antibiotic resistance is a worldwide problem. Within the 4 years before the turn of the millennium Helicobacter pylori strains isolated in children living in Vienna, Austria, showed a primary clarithromycin and metronidazole resistance of 20% and 16%, respectively. The aim of this retrospective follow-up survey was to assess the further development and current antimicrobial resistance status. METHODS: Children having undergone upper endoscopy between March 2002 and March 2008 at the same two co-operating pediatric gastroenterology units which had also been collaborating on the prior assessment were included. H. pylori infection was diagnosed by rapid urease test, histology, and culture. If the latter was positive, susceptibility testing to amoxicillin, clarithromycin and metronidazole by E-test followed. From March 2004 onwards, susceptibility to levofloxacin, tetracycline and rifampin was additionally assessed. RESULTS: Out of 897 children, 153 had a proven infection with H. pylori and no history of prior eradication treatment. Their median age was 11.5 years (range 0.5-20.9 years). Primary resistance to clarithromycin and metronidazole were 34% and 22.9%, respectively; dual resistance was found in 9.8% of the strains; 0.9% was resistant to tetracycline and rifampin, respectively. No case of amoxicillin resistance was detected. The only independent risk factor for clarithromycin resistance turned out to be the origin of a child from Austrian parents. CONCLUSIONS: In the last decade, the rate of primary resistance of H. pylori to clarithromycin continued to rise. No significant change was found regarding primary resistance to metronidazole or dual resistance to metronidazole and clarithromycin, respectively.

Stool polymerase chain reaction for Helicobacter pylori detection and clarithromycin susceptibility testing in children.

BACKGROUND & AIMS: This study was undertaken in a pediatric gastroenterology clinic to retrospectively evaluate a real-time polymerase chain reaction (PCR) for the detection and clarithromycin susceptibility testing of Helicobacter pylori using stool specimens. METHODS: All consecutive children who underwent a gastroscopy between March 2006 and February 2009 and also having been examined by stool PCR were enrolled. Rapid urease test, histology, and culture were the reference methods for the detection of H pylori and E-test for susceptibility testing, respectively. RESULTS: A total of 143 children (mean age, 10.8 y; range, 2.8-17.9; males:females, 1:1.5) were evaluable. Sensitivity, specificity, and test accuracy for the detection of H pylori were 83.8%, 98.4%, and 90.2%, respectively. Sensitivity, specificity, and accuracy for the detection of clarithromycin resistance were 89.2%, 100%, and 94.0%, respectively. CONCLUSIONS: Stool PCR was a reliable and useful noninvasive tool for detection and clarithromycin susceptibility testing of H pylori in a pediatric population with a high prevalence of clarithromycin-resistant strains.

Vitamin E treatment for children with chronic hepatitis B: a randomized placebo controlled trial.

AIM: To evaluate the safety and efficacy of Vitamin E in children with chronic hepatitis B. METHODS: We randomly assigned patients with chronic hepatitis B, positive for hepatitis B e antigen (HBeAg), to receive either Vitamin E or placebo once daily for 6 mo in a 3:1 ratio and double-blind manner. The primary end point was HBeAg seroconversion, defined as the loss of HBeAg, undetectable levels of serum hepatitis B virus DNA, and the appearance of antibodies against HBeAg 12 mo after therapy. RESULTS: At baseline visit, 49 patients had normal and 43 had increased serum aminotransferase levels. Twenty-nine patients did not respond to previous treatment with interferon-alpha or lamivudine. Seventy-six children completed the study; 16 were non-compliant (n = 7), lost to follow-up (n = 7), or started another antiviral treatment (n = 3). Intention-to-treat analysis showed HBeAg seroconversion in 16 children (23.2%) treated with Vitamin E and two (8.7%) in the placebo group (P = 0.13). Vitamin E was well tolerated. CONCLUSION: There is only a tendency that Vitamin E may promote HBeAg seroconversion. Therefore larger studies are needed to clarify the role of antioxidants in the therapy of chronic hepatitis B.