The effect of various forms of selenium supplied to pregnant goats on the levels of selenium in the body of their kids at the time of weaning

The aim of this trial was to compare the effect of long-term supplementation of goats with different forms of selenium on body reserves of selenium in their kids at the time of weaning. Thirty-three pregnant goats were divided into five groups. Group C was control while the other four groups were supplemented with selenium (Se) for 6 weeks before parturition (0.3 mg/goat/day) and after parturition (0.9 mg/goat/day). Group "Se-I" received sodium selenite and three other groups received organic forms: "Se-L," lactate-protein complex; "Se-P," Se-proteinate; and "Se-Y," Se-yeast. The kids were weaned at 3 months of age and samples of tissues (liver, pancreas, myocardium, lungs, kidneys, spleen, thigh, tongue, and diaphragm) were taken after slaughtering. The long-term supplementation of goats with Se influenced Se concentration in all examined tissues of kids. Significant differences (p≤0.01) were found between the control and all experimental groups, except for the renal cortex and pancreas (Se-I). The average increase of Se concentration in overall examined tissues in comparison with the control (100%) was as follows: Se-Y, 192%; Se-P, 167%; Se-L, 161%; Se-I, 144%. The highest efficiency was found in the group supplemented with Se-yeast with a high content of selenomethionine, also the other two organic forms of Se were more efficient than the inorganic form.

Synergistic effects in competitive adsorption of carbohydrates on an ion-exchange resin

Adsorption of the three carbohydrates sucrose, glucose and fructose from aqueous solutions was investigated on an ion-exchange resin. The adsorption equilibrium of single components, binary and ternary mixtures was quantified by frontal analysis and the adsorption-desorption method. The experiments covered a concentration range up to 600 g/L at 60 degrees C and 80 degrees C. Within this range the adsorption isotherms of carbohydrates exhibited anti-Langmuirian behavior. Data of mixture adsorption revealed reversed competitive (synergistic or cooperative) effects, i.e., an increase of the concentration of one component of the mixture enhanced the adsorption of others. To model such an adsorption behavior the anti-Langmuir model has been used. The isotherm parameters determined for single components were used to simulate the competitive adsorption equilibria through the IAS (ideal adsorbed solution) theory. Finally, dynamic concentration profiles of multicomponent mixtures have been recorded. The shapes of adsorption and desorption curves confirmed the observed competitive effects found in the equilibrium studies. The breakthrough curves measured were simulated using the equilibrium theory as well as a numerical solution of the equilibrium dispersive model.

Esomeprazole-based 1-week triple therapy directed by susceptibility testing for eradication of Helicobacter pylori infection in children

BACKGROUND

Poor compliance to therapy and antibiotic resistance are the main causes for failure of anti-Helicobacter pylori therapy.

OBJECTIVE

To evaluate the effectiveness of esomeprazole-based triple therapy directed by susceptibility testing.

METHODS

Symptomatic children with H. pylori infection, who underwent successful susceptibility testing and were colonized by no double-resistant strain, received 1-week triple therapy with esomeprazole, amoxicillin and either clarithromycin or metronidazole. Success of eradication was investigated by C-urea breath test.

RESULTS

Fifty-eight children (median age, 11.4 years; range, 2.2-17.7 years; 81% immigrants) were included. Helicobacter pylori was resistant to clarithromycin in 5 (9%) and to metronidazole in 9 children (16%). Eradication was successful in 49 (92%) of 53 children receiving esomeprazole, amoxicillin and clarithromycin and in all 5 children treated with metronidazole instead of clarithromycin, resulting in an eradication rate of 93% (95% confidence interval, 83%-98%, intention-to-treat analysis). All 4 treatment failures occurred in immigrants with language problems; 2 of them were obviously noncompliant.

CONCLUSION

Esomeprazole-based 1-week triple therapy directed by susceptibility testing is highly effective for eradication of H. pylori infection in children.

Comparison of possible arrangements of five identical columns in preparative chromatography

Goal of the paper is to demonstrate how configuration of a certain number of identical HPLC columns influences on the effectiveness of the isolation of a target component. There are two extreme configurations: all the available columns are operated in parallel (provided there are enough pumps available) or all the columns are connected in series. Various combinations of columns connected parallel and in series are possible. Besides batch operation more sophisticated multicolumn arrangements allowing continuous separation are considered. In particular, in this work different configurations of five columns were examined. For illustration the separation of a binary mixture was considered. As the objective function the productivity of the less retained component has been used. A standard model capable to describe the propagation of chromatographic bands has been used to optimize the operating conditions for various possible multicolumn arrangements.

7-day triple therapy of Helicobacter pylori infection with levofloxacin, amoxicillin, and high-dose esomeprazole in patients with known antimicrobial sensitivity

BACKGROUND AND AIMS

Failed primary anti-Helicobacter pylori therapy results in a high rate of antimicrobial resistance. This necessitates a search for new regimens to cure H. pylori infection. The aim of this study was to evaluate the efficacy and tolerability of a new levofloxacin-containing 7-day triple therapy and to compare it with that of standard French triple therapy in patients with known H. pylori susceptibility to MET (metronidazole) and CLA (clarithromycin).

PATIENTS AND METHODS

Sixty-one patients with documented antibiotic sensitivity (E-test) and an indication for anti-H. pylori treatment based on the Maastricht Consensus 2/2000 guidelines were randomized to receive either esomeprazole 2 x 40 mg, levofloxacin 2 x 500 mg, and amoxicillin 2 x 1 g for 7 days (ELA, n = 30), or esomeprazole 2 x 20 mg, clarithromycin 2 x 500 mg, and amoxicillin 2 x 1 g for 7 days (ECA, n = 31). A cure check was performed 4-6 weeks after conclusion of therapy.

RESULTS

Sixty-one patients were randomized to the two treatment groups. Twenty-eight of 30 patients of the ELA group were available for per-protocol (PP) analysis, of whom 26 (92.9% CI: 76-99%; intention-to-treat [ITT] analysis 86.7% CI: 68-96%) became H. pylori negative compared with 26 of the 31 patients of the ECA group (83.9%, CI: 66-93% both PP and ITT analyses). Five patients of the ELA group showed CLA resistance, three of whom also showed MET resistance, and all five were treated successfully. Two patients with levofloxacin-resistant strains, one in each group, were cured. Both regimens were generally well tolerated with minor adverse events being seen in 15 patients (51.7%) of the ELA group and in 13 (40.6%) of the ECA group. None of the patients discontinued treatment prematurely due to adverse events.

CONCLUSION

The data of this pilot study suggest a better than 80% efficacy of the new 7-day levofloxacin triple therapy, which is within the range of the French triple therapy in patients with MET- and CLA-susceptible strains. The data suggest that the new levofloxacin triple therapy may also be an option in patients with MET- and CLA-resistant H. pylori strains.

Evaluation of a novel rapid one-step immunochromatographic assay for detection of monoclonal Helicobacter pylori antigen in stool samples from children

A new rapid one-step immunochromatographic test using monoclonal antibodies for detection of Helicobacter pylori antigen in stool in children was evaluated on coded stool samples from 159 children (mean age, 9.7 +/- 5.0 years; 118 from Munich, 41 from Vienna): 86 children were H. pylori infected defined by positive culture and/or > or =2 other positive tests ([13C]urea breath test, histology, rapid urease test), and 73 children showed concordant negative results. Seventy-nine patients (12.1 +/- 3.8 years; 42 from Munich; 37 from Vienna) were tested 6 to 8 weeks after anti-Helicobacter pylori therapy with urea breath test and stool test. In Munich, all 160 tests (118 pre- and 42 posttreatment) were independently read by two observers. Equivocal results were excluded for calculation of sensitivity and specificity but were considered as false to assess accuracy. The two observers in Munich agreed in 63 out of 65 positive and 89 out of 95 negative results, while eight times (5.0%) they judged the test as equivocal. Pretreatment and posttreatment results for sensitivity were 88.1% (79.2 to 94.1) and 88.9% (51.8 to 99.7), specificity 88.1% (77.8 to 94.1) and 93.9% (85.2 to 98.3), and accuracy 83.5% and 81.5%, respectively. We conclude that the new monoclonal immunochromatographic quick test shows a good interobserver agreement, but equivocal results occur in 5%. Performance is comparable before and after therapy. The test may become a good alternative in children in settings where a [13C]urea breath test or a reliable enzyme immunoassay stool test are not available.

Effect of mobile phase composition on the SMB processes efficiency

The solvent composition was adjusted in a theoretical study in order to maximize the efficiency of a simulated moving bed (SMB) process. The isocratic realization of the process as well as the solvent gradient mode were considered. The solvent composition and the flow rates were used as decision variables in a random search optimization algorithm known to be a reliable tool for nonlinear programming problems. The results of the optimization indicate that the optimal composition of the mobile phase depends strongly on the feed concentration. The asymmetry of the internal concentration profiles, which has a negative effect on the separation efficiency, can be partly damped by an increase of the solvent strength. In the cases studied the optimal solvent strength determined for concentrated feed streams is higher than that for diluted ones. Moreover, the optimum is strongly influenced by the value of the selectivity factor and its dependency on the mobile phase composition. Different results were obtained for cases, in which the separation factor increases with increasing the modifier concentration, than for cases, in which the separation factor decreases with increasing the modifier concentration. A similar analysis was performed for a solvent gradient SMB process, in which different solvents are used at the two inlet ports: a weak solvent in the feed stream and a strong solvent in the desorbent stream. Again the optimal mobile phase composition was strongly affected by the type of the isotherms and their non-linearity. The potential of a gradient SMB process in terms of increasing the productivity and reducing the eluent consumption is exemplified.

Long-term follow-up after complete ablation of Barrett’s esophagus with argon plasma coagulation

AIM: To report the long-term outcome of patients after complete ablation of non-neoplastic Barrett’s esophagus (BE) with respect to BE relapse and development of intraepithelial neoplasia or esophageal adenocarcinoma.

METHODS: In 70 patients with histologically proven non-neoplastic BE, complete BE ablation was achieved by argon plasma coagulation (APC) and high-dose proton pump inhibitor therapy (120 mg omeprazole daily). Sixty-six patients (94.4%) underwent further surveillance endoscopy. At each surveillance endoscopy four-quadrant biopsies were taken from the neo-squamous epithelium at 2 cm intervals depending on the pre-treatment length of BE mucosa beginning at the neo-Z-line, and from any endoscopically suspicious lesion.

RESULTS: The median follow-up of 66 patients was 51 mo (range 9-85 mo) giving a total of 280.5 patient years. A mean of 6 biopsies were taken during surveillance endoscopies. In 13 patients (19.7%) tongues or islands suspicious for BE were found during endoscopy. In 8 of these patients (12.1%) non-neoplastic BE relapse was confirmed histologically giving a histological relapse rate of 3% per year. In none of the patients, intraepithelial neoplasia nor an esophageal adenocarcinoma was detected. Logistic regression analysis identified endoscopic detection of islands or tongues as the only positive predictor of BE relapse (P = 0.0004).

CONCLUSION: The long-term relapse rate of non-neoplastic BE following complete ablation with high-power APC is low (3% per year).

Comparative modeling of breakthrough curves of bovine serum albumin in anion-exchange chromatography

The experimental results of a previous study of the mass transfer kinetics of bovine serum albumin (BSA) in ion-exchange chromatography, under nonlinear conditions, were reevaluated using the general rate model of chromatography. Solutions of this model were obtained numerically. The influences of axial dispersion, the resistance to mass transfer from the bulk mobile phase to the surface of the packing particles, and the intraparticle mass transfer resistances on the profiles of the breakthrough curves of BSA were investigated. The results obtained are compared to those of a previous investigation of the same data, using the simple transport-dispersive model and the lumped pore diffusion model. The results obtained show that the use of an oversimplified model for the analysis of chromatographic data can lead to erroneous interpretations of the experimental data and to misunderstandings of the fundamentals of the processes involved. Finally, a theoretical comparison between the properties and the range of application of the three models is provided.

Inducible nitric oxide synthase and Salmonella infection

Salmonella infection is associated with the increased expression of inducible nitric oxide synthase in macrophages and other cells. This review summarizes current knowledge of the molecular mechanisms involved in the induction process, and discusses the functional significance of nitric oxide production in the context of host defense against Salmonella.

Helicobacter pylori and gastric cancer: current status of the Austrain-Czech-German gastric cancer prevention trial (PRISMA-Study)

AIM: To test the hypothesis that Helicobacter pylori eradication alone can reduce the incidence of gastric cancer in a subgroup of individuals with an increased risk for this fatal disease.

METHODS: It is a prospective, randomized, double blind, placebo controlled multinational multicenter trial. Men between 55 and 65 years of age with a gastric cancer phenotype of Helicobacter pylori gastritis are randomized to receive a 7 day course of omeprazole 2 × 20 mg, clarithromycin 2 × 500 mg, and amoxicillin 2 × 1 g for 7 days, or omeprazole 2 × 20 mg plus placebo. Follow-up endoscopy is scheduled 3 months after therapy, and thereafter in one-year intervals. Predefined study endpoints are gastric cancer, precancerous lesions (dysplasia, adenoma), other cancers, and death.

RESULTS: Since March 1998, 1524 target patients have been screened, 279 patients (18.3%) had a corpus dominant type of H. pylori gastritis, and 167 of those were randomized (58.8%). In the active treatment group (n = 86), H. pylori infection infection was cured in 88.9% of patients. Currently, the cumulative follow-up time is 3046 months (253. 38 patient years, median follow up 16 months). So far, none of the patients developed gastric cancer or any precancerous lesion. Three (1.8%) patients reached study endpoints other than gastric cancer.

CONCLUSION: Among men between 55 and 65 years of age, the gastric cancer phenotype of H. pylori gastritis appears to be more common than expected. Further follow up and continuing recruitment are necessary to fulfil the main aim of the study.

Inducible nitric oxide synthase expression before and after eradication of Helicobacter pylori in different forms of gastritis

An increased expression of inducible nitric oxide synthase (iNOS) has been observed in the inflamed human gastric mucosa as well as in some tumors. This observation suggests a pathobiological role of elevated NO production. The purpose of this study was to compare the immunohistochemical iNOS expression in the different kinds of gastritis before and after the eradication of Helicobacter pylori. We performed iNOS and H. pylori immunohistochemical staining and counted iNOS positive cells. We detected elevated expression of iNOS around sites infected with H. pylori. iNOS expression in chemical gastritis was strongly elevated in mucosal glands. After treatment, we found a significant difference in iNOS expression in patients with classical H. pylori-induced antrum predominant gastritis and in patients with active autoimmune gastritis. In the special case of progressed gastritis with intestinal metaplasia we found persistence of intestinal metaplasia, and we could not find a significant difference in the number of positive iNOS cells before and after treatment. The persistence of IM as a possibly precancerous lesion is probably at least in the antrum a source of continuous iNOS induction even after H. pylori eradication.

Ablation of Barrett's epithelium by endoscopic argon plasma coagulation in combination with high-dose omeprazole

BACKGROUND

Barrett's esophagus is a premalignant condition induced by gastroesophageal reflux. The aim of this prospective study was to assess the efficacy of argon plasma coagulation in combination with high-dose omeprazole therapy to ablate nondysplastic Barrett's epithelium.

METHODS

In 73 patients with histologically confirmed Barrett's epithelium, argon plasma coagulation was used in combination with maximal acid suppression (omeprazole 40 mg three times a day). Histologic and endoscopic changes were evaluated at 6- and 12-month intervals.

RESULTS

In 69 of 70 patients (98.6%) complete squamous regeneration was achieved after a median of 2 argon plasma coagulation sessions (range 1 to 5). During a median follow-up of 12 months (range 2 to 51 months) there has been no relapse or evidence of the development of dysplasia under continuous acid suppression. Three patients (4.3%) developed a mild stricture of the distal esophagus that resolved after a single session of bougie dilation.

CONCLUSIONS

In our experience, argon plasma coagulation in combination with high-dose omeprazole treatment is an effective and safe technique for complete ablation of nondysplastic Barrett's epithelium. Restoration of squamous mucosa after argon plasma coagulation appears to be long-lasting.

Determination of mobile phase effect on single-component adsorption isotherm by use of numerical estimation

Numerical estimation was used to determine adsorption isotherm parameters of a single-component in a normal-phase system. The distribution isotherm of methyl deoxycholate was described between the mobile phase containing hexane, ethyl acetate, methanol with varied concentration and a silica gel adsorbent. The effect of the mobile phase composition on the isotherm parameters and the band profiles was investigated. The results obtained were used to simulate the overload gradient elution. The validity of the method proposed was verified by comparison of the computer simulations with the experimental band profiles.

Calculation of chromatographic band profiles with an implicit isotherm

The numerical method for solving the mathematical model of chromatography process coupled with implicit isotherm has been proposed. The exemplary predictions of elution band profiles were performed for competitive adsorption data of 2-phenylethanol and 3-phenylpropanol on ODS-silica with methanol-water as the mobile phase. The simulations of chromatography process with various isotherm models taking into account lateral interactions in adsorbed phase and surface heterogeneity were discussed.