Heterogeneity in susceptibility to metronidazole among Helicobacter pylori isolates from patients with gastritis or peptic ulcer disease

Combination therapies that include metronidazole (MTZ) are the most successful therapies used in eradicating Helicobacter pylori. In this study, the prevalence and the relevance of heterogeneity in susceptibility to MTZ among H. pylori populations of 156 patients were evaluated. The results of this study show that 37 patients (24%) were infected with MTZ-resistant H. pylori (MIC > or = 8 micrograms/ml). Furthermore, 33% (52 of 156) of the patients were found to be infected with H. pylori populations heterogeneous for their susceptibility to MTZ. The reassessment of the MICs of MTZ for these 52 H. pylori populations revealed MTZ resistance in 28 of them, increasing the number of MTZ-resistant H. pylori populations among the 156 patients to 65 (42%). Out of 20 isolates, 2 (10%) heterogeneous in their susceptibility to MTZ also appeared to be heterogeneous at the genome level as determined by randomly amplified polymorphic DNA fingerprinting. In conclusion, the results show the limitations and risk of possible misinterpretations when only a single colony, picked from the primary H. pylori populations isolated from patients, is analyzed for its susceptibility to MTZ.     

Separate assessment of porosity and uncombined carbon in cemented carbides

Porosity and uncombined carbon in cemented carbides are traditionally assessed by comparison to standardized microstructure charts, such as those in ISO 4505-1978. To improve the accuracy in the characterization a fully automatic image analysis procedure has been developed. The analysis is performed using light optical microscopy on unetched polished specimens. The implemented algorithm separates uncombined carbon, C-defects, from pores, A- and B-defects. Pores are approximately distributed in a random way in the structure. Uncombined carbon is on the other hand precipitated into clusters of carbon particles. This difference is together with defect size used as a base for the separation. Small defects situated close together are classified as C-defects, small isolated defects as A-pores and large defects as B-pores. Pores are found to be more round than the somewhat elongated C-defects. The difference in shape is significant and can also be used as a separation criterion.

Image analysis is used to quantitatively characterise the ISO 4505-1978 standard charts with respect to volume fraction, number density and size distribution of defects. The results are compared to measured distributions for true microstructures.     

T cell responsiveness correlates differentially with antibody isotype levels in clinical and asymptomatic filariasis

To establish the relationships among T and B cell responses, active infection, and clinical manifestations in lymphatic filariasis, filarial-specific lymphocyte proliferation, IgG antibody isotypes, and IgE levels were determined in an exposed population: 31 asymptomatic amicrofilaremics, 43 microfilaremics, 12 symptomatic amicrofilaremics, and 52 elephantiasis patients. Lymphocyte proliferation was higher in elephantiasis patients and asymptomatic amicrofilaremics than in microfilaremics (P < .004). A proportion of asymptomatic amicrofilaremics (32%), elephantiasis patients (37%), and symptomatic amicrofilaremics (58%) showed antigen-specific lymphocyte unresponsiveness, and lymphocyte proliferation to filarial antigens correlated negatively with specific IgG4 levels (rho = -0.315, P < .001). As elevated specific IgG4 is an indicator of active infection, it is argued that active infection may result in lymphocyte hyporesponsiveness irrespective of clinical category. Of those with elevated specific IgE levels and high T cell proliferative responses, 70% had elephantiasis, suggesting these factors have a role in pathology. However, the existence of a proportion of elephantiasis patients with low anti-filarial IgE and T cell unresponsiveness to filarial antigens suggests that elephantiasis can be caused by distinct processes.     

A numerical model for the dissolution of spherical particles in binary alloys under mixed mode control

A general numerical model is described for the dissolution kinetics of spherical particles in binary systems for any combination of first order reactions at the particle-matrix interface and long distance diffusion within the matrix. The model is applicable to both finite and infinite media and handles both complete and partial particle dissolution. It is shown that interfacial reactions can have a strong effect on the dissolution kinetics, the solute concentration at the particle-matrix interface and the solute concentration profile in the matrix.     

Consumption of reduced-fat products: effects on parameters of anti-oxidative capacity

Plasma levels of fibrinogen, factor VIIc and prothrombin fragment F1 + 2, a marker of thrombin generation in vivo, were studied in 68 subjects with serum total cholesterol (TC) levels between 135 and 349 mg/dl but without clinical evidence of cardiovascular disease and other atherosclerotic risk factors. F1 + 2 plasma levels were directly correlated with TC (p < 0.0004), low-density lipoprotein cholesterol (LDL-C; p < 0.0018) and factor VIIc (p < 0.024). Thirty-five subjects with TC greater than 249 mg/dl (median value of the whole group) showed higher levels of F1 + 2 (p < 0.0001) and fibrinogen (p < 0.0015) than those with TC lower than 249 mg/dl. In subjects with TC > 249 mg/dl and F1 + 2 > 1.2 nM (median value of the whole group), a cholesterol-lowering drug (simvastatin) was able to reduce F1 + 2 (p < 0.009) as well as TC and LDL-C. This study shows a relationship between serum cholesterol and the rate of thrombin generation supporting the hypothesis that a hypercoagulable state may occur in hypercholesterolemic subjects before the onset of clinical evidence of atherosclerotic cardiovascular disease.     

Finances and Well-Being: A Dynamic Equilibrium Model of Resources.

This study of 513 Dutch farmers tested a dynamic equilibrium model of resources (an extension of the conservation of resources theory; S. E. Hobfoll, 1989, 1998, 2001). With structural equation modeling, the advantages of a 3-wave longitudinal design were comprehensively used, such as addressing bidirectional causal effects and within-individual vs. between-individual change. This allowed for a careful analysis of the management function of resources in the stress process. Results showed that well-being had stronger within-person stability than finances. Increased levels of financial problems temporarily increased psychological distress but not self-reported illness. Conversely, farmers with higher stable baselines of psychological distress also had higher baselines of self-reported illness and experienced more negative changes in their financial situation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syntax and consistent equation semantics of hybrid Chi

The hybrid χ (Chi) formalism integrates concepts from dynamics and control theory with concepts from computer science, in particular from process algebra and hybrid automata. It integrates ease of modeling with a straightforward, structured operational semantics. Its ‘consistent equation semantics’ enforces state changes to be consistent with delay predicates, that combine the invariant and flow clauses of hybrid automata. Ease of modeling is ensured by means of the following concepts: (1) different classes of variables: discrete and continuous, of subclass jumping or non-jumping, and algebraic; (2) strong time determinism of alternative composition in combination with delayable guards; (3) integration of urgent and non-urgent actions; (4) differential algebraic equations as a process term as in mathematics; (5) steady-state initialization; and 6) several user-friendly syntactic extensions. Furthermore, the χ formalism incorporates several concepts for complex system specification: (1) process terms for scoping that integrate abstraction, local variables, local channels and local recursion definitions; (2) process definition and instantiation that enable process re-use, encapsulation, hierarchical and/or modular composition of processes; and (3) different interaction mechanisms: handshake synchronization and synchronous communication that allow interaction between processes without sharing variables, and shared variables that enable modular composition of continuous-time or hybrid processes. The syntax and semantics are illustrated using several examples.     

The impact of cleaner processing on nutrient availability in the bleached kraft industry.

The pulp and paper industry has invested heavily over recent years in cleaner processing, to reduce losses and minimise its impact on the environment. Over the past fifteen years, a New Zealand integrated bleached kraft mill has undergone a comprehensive programme of upgrades to increase production, reduce water consumption and streamline its biological treatment process. Whilst the overall discharge of contaminants from the site decreased, the treatment system performance did not show a concurrent improvement as may have been expected. Reduced BOD removal, low dissolved oxygen levels, and poor solids settlability were symptomatic of phosphorus limitation in the aerated lagoon treatment system. The wastewater entering the system was found to be phosphorus limited at a BOD:P ratio of 100:0.2. Mono-ammonium-phosphate was supplemented, at approximately 30 kg P/d, to raise the phosphorus levels to a BOD:P ratio of 100:0.3. Treatment efficiencies improved very quickly after phosphorus dosage, with a 50% reduction in BOD and TSS discharge, a significant increase in dissolved oxygen levels, and improved BOD removal (85% to 93%). This case study demonstrates that whilst more closed operation can result in reduced discharge of organic loads, there may be negative impacts on the availability of nutrients for balanced biological growth.