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Background: A remarkable variety of restriction-modification (R-M) systems is found in Helicobacter pylori. Since they encompass a large portion of the strain-specific H. pylori genes and therefore contribute to genetic variability, they are suggested to have an impact on disease outcome. Type I R-M systems comprise three different subunits and are the most complex of the three types of R-M systems., Aims: We investigated the genetic diversity and distribution of type I R-M systems in clinical isolates of H. pylori., Material and Methods: Sixty-one H. pylori isolates from a Swedish hospital based case-control study and 6 H. pylori isolates of a Swedish population-based study were analyzed using polymerase chain reaction for the presence of the three R-M systems' subunits. Representative gene variants were sequenced., Results: Although the hsdM and hsdR genes appeared conserved in our clinical H. pylori isolates, the sequences of the hsdS loci were highly variable. Despite their sequence diversity, the genes per se were present at high frequencies. We identified a number of novel allelic hsdS variants, which are distinct from corresponding hsdS loci in the sequenced H. pylori strains 26695, J99 and HPAG1. In analyses of paired H. pylori isolates, obtained from the same individuals with a 4-year interval, we observed genetic modifications of hsdS genes in patients with atrophic gastric mucosa., Discussion: We propose that the genetic variability of hsdS genes in a bacterial population will give rise to new specificities of these enzymes, which might lead to adaptation to an ever-changing gastric environment.

Helicobacter pylori-related disease is at least partially attributable to the genotype of the infecting strain, particularly the presence of specific virulence factors. We investigated the prevalence of a novel combination of H. pylori virulence factors, including the cag pathogenicity island (PAI), and their association with severe disease in isolates from the three major ethnicities in Malaysia and Singapore, and evaluated whether the cag PAI was intact and functional in vitro. Polymerase chain reaction (PCR) was used to detect dupA, cagA, cagE, cagT, cagL and babA, and to type vacA, the EPIYA motifs, HP0521 alleles and oipA ON status in 159 H. pylori clinical isolates. Twenty-two strains were investigated for IL-8 induction and CagA translocation in vitro. The prevalence of cagA, cagE, cagL, cagT, babA, oipA ON and vacA s1 and i1 was >85%, irrespective of the disease state or ethnicity. The prevalence of dupA and the predominant HP0521 allele and EPIYA motif varied significantly with ethnicity (p < 0.05). A high prevalence of an intact cag PAI was found in all ethnic groups; however, no association was observed between any virulence factor and disease state. The novel association between the HP0521 alleles, EPIYA motifs and host ethnicity indicates that further studies to determine the function of this gene are important.

Sulfate-reducing bacteria (SRB) belonging to the metabolically versatile Desulfobacteriaceae are abundant in marine sediments and contribute to the global carbon cycle by complete oxidation of organic compounds. Desulfobacterium autotrophicum HRM2 is the first member of this ecophysiologically important group with a now available genome sequence. With 5.6 megabasepairs (Mbp) the genome of Db. autotrophicum HRM2 is about 2 Mbp larger than the sequenced genomes of other sulfate reducers (SRB). A high number of genome plasticity elements (> 100 transposon-related genes), several regions of GC discontinuity and a high number of repetitive elements (132 paralogous genes Mbp(-1)) point to a different genome evolution when comparing with Desulfovibrio spp. The metabolic versatility of Db. autotrophicum HRM2 is reflected in the presence of genes for the degradation of a variety of organic compounds including long-chain fatty acids and for the Wood-Ljungdahl pathway, which enables the organism to completely oxidize acetyl-CoA to CO(2) but also to grow chemolithoautotrophically. The presence of more than 250 proteins of the sensory/regulatory protein families should enable Db. autotrophicum HRM2 to efficiently adapt to changing environmental conditions. Genes encoding periplasmic or cytoplasmic hydrogenases and formate dehydrogenases have been detected as well as genes for the transmembrane TpII-c(3), Hme and Rnf complexes. Genes for subunits A, B, C and D as well as for the proposed novel subunits L and F of the heterodisulfide reductases are present. This enzyme is involved in energy conservation in methanoarchaea and it is speculated that it exhibits a similar function in the process of dissimilatory sulfate reduction in Db. autotrophicum HRM2.

High dietary intake of fruits and vegetables is associated with a reduced disease risk. Therefore, clinical interest is growing in therapies based on dietary supplements and effects of food components. Immune-modulatory and barrier-protective effects have been described for the amino acid glutamine and the trace element zinc. In Caco-2-cells, zinc is necessary to maintain the expression of proteins like ZO-1 and occludin, and experimental evidence exists that glutamine has enterocyte-protective effects and modulates intestinal barrier function in stressed animals and humans. Polyunsaturated fatty acids (PUFA) improve paracellular permeability after IL-4 incubation. Enhancement of barrier properties by long-chain PUFA is discussed controversially, but a beneficial role preventing the redistribution of occludin and ZO-1 and reduction of epithelial resistance by IFN-gamma and TNF-alpha exists. In addition, a group of secondary plant compounds, the polyphenols, are supposed to be important in this respect. The flavonoid quercetin and its metabolite DHBA increased epithelial resistance of Caco-2-cells to 157 +/- 4% of control values, and DHBA up to 119 +/- 4% of control values, respectively. This is due to a 2.3 +/- 0.1-fold expression rate of the tight junction protein claudin-4.

Background: The putative H. pylori pathogenicity-associated factor dupA has been associated with IL-8 induction in vitro, and duodenal ulcer (DU) and gastric cancer (GC) development in certain populations, but this association is inconsistent between studies. We aimed to investigate dupA prevalence in clinical isolates from Sweden, Australia and from ethnic Chinese, Indians and Malays resident in Malaysia and Singapore and to examine the association with DU and GC. In addition we investigated the sequence diversity between isolates from these diverse groups and compared the level of IL-8 secretion in isolates possessing and lacking dupA., Methods: PCR primers were designed to amplify over the C/T insertion denoting a continuous dupA. PCR products from 29 clinical isolates were sequenced and compared with sequences from three additional strains obtained from GenBank. Clinical isolates from 21 Malaysian patients (8 dupA-positive, 14 dupA-negative) were assessed for their ability to induce IL-8 in AGS cells in vitro. Statistical analysis was performed using Fisher's exact test., Results: The prevalence of dupA in isolates from Swedish functional dyspepsia (FD) control patients (65%, 13/20) was higher and in isolates from Indian FD patients (7.1%, 3/42) was lower as compared with isolates from Chinese (28.9%, 13/49, P = 0.005, P = 0.025), Malay (35.7%, 5/14, P = 0.16, P = 0.018) and Australian (37.8%, 17/45, P = 0.060, P < 0.001) FD patients. dupA was associated with DU and GC development in Chinese with 62.5% (10/16) and 54.6% (12/22) of isolates possessing dupA respectively as compared with FD controls (28.9%) (P = 0.015, P = 0.032). No significant difference in prevalence of dupA between FD controls, DU (63.6%, 7/11) and GC (61.9%, 13/21) cases (P = 1.000) was observed in the Swedish population. Sequence analysis revealed a pairwise variation of 1.9% and all isolates possessed the C/T insertion. The average IL-8 induction was 1330 pg/mL for dupA-positive isolates and 1378 pg/mL for dupA-negative isolates., Conclusion: Although dupA is highly conserved when present, we identified no consistent association between dupA and DU or GC development across the ethnic groups investigated, with the dupA prevalence in control groups varying significantly. Our results would suggest that in the clinical isolates investigated dupA is not associated with IL-8 induction in vitro.

Objective: This study tested the findings of a prior study indicating a therapeutic relationship between consumption of betel nut and symptoms of schizophrenia., Method: The subjects were 65 outpatients with diagnoses of schizophrenia or schizoaffective disorder. Symptoms rated with the Positive and Negative Syndrome Scale were compared between high- and low-consumption betel chewers in a repeated-measures design. Movement disorders were assessed with the Abnormal Involuntary Movement Scale and Simpson-Angus Rating Scale. Global health and social functioning were assessed with the Medical Outcomes Study 12-item and 36-item Short-Form Health Surveys, respectively., Results: Male high-consumption betel chewers had significantly milder positive symptoms than low-consumption chewers over 1 year. Betel chewing was not associated with global health, social functioning, or movement disorders. Betel chewing was associated with tobacco use but not with cannabis or alcohol., Conclusions: These findings have clinical significance in betel-chewing regions and broader implications for theory of muscarinic neurophysiology in schizophrenia.

The enteric bacterium Escherichia blattae has been analyzed for the presence of cobalamin (B12) biosynthesis and B12-dependent pathways. Biochemical studies revealed that E. blattae synthesizes B12 de novo aerobically and anaerobically. Genes exhibiting high similarity to all genes of Salmonella enterica serovar Typhimurium, which are involved in the oxygen-independent route of B12 biosynthesis, were present in the genome of E. blattae DSM 4481. The dha regulon encodes the key enzymes for the anaerobic conversion of glycerol to 1,3-propanediol, including coenzyme B12-dependent glycerol dehydratase. E. blattae DSM 4481 lacked glycerol dehydratase activity and showed no anaerobic growth with glycerol, but the genome of E. blattae DSM 4481 contained a dha regulon. The E. blattaedha regulon is unusual, since it harbors genes for two types of dihydroxyacetone kinases. The major difference to dha regulons of other enteric bacteria is the inactivation of the dehydratase-encoding gene region by insertion of a 33,339-bp prophage (MuEb). Sequence analysis revealed that MuEb belongs to the Mu family of bacteriophages. The E. blattae strains ATCC 33429 and ATCC 33430 did not contain MuEb. Accordingly, both strains harbored an intact dehydratase-encoding gene region and fermented glycerol. The properties of the glycerol dehydratases and the correlating genes (dhaBCE) of both strains were similar to other B12-dependent glycerol and diol dehydratases, but both dehydratases exhibited the highest affinity for glycerol of all B12-dependent dehydratases characterized so far. In addition to the non-functional genes encoding B12-dependent glycerol dehydratase, the genome of E. blattae DSM 4481 contained the genes for only one other B12-dependent enzyme, the methylcobalamin-dependent methionine synthase., (Copyright (c) 2004 S. Karger AG, Basel.)

An experimental study of the role of metallothioneins (MTs) in Cd and Zn depuration processes in the freshwater bivalve Corbicula fluminea was conducted after in situ exposure on the river Lot (France). Specimens of adult C. fluminea were first transplanted from a lacustrine reference site to a polymetallic polluted station (Bouillac, (B)) for a 42-days' exposure period from September to November 1996. They were then depurated after transfer to the laboratory, and were sub-sampled periodically until May 1997. During the first phase, MT concentrations measured with the Mercury-Saturation Assay were induced for a factor of 3.5 compared with time 0, whereas metal uptake showed accumulation factors of 17 and 4 for Cd and Zn, respectively. During the depuration phase, Cd and Zn concentrations decreased by 18 and 70%, respectively, giving estimated biological half-lives of 500 and 40 days. During the same period, MT concentrations decreased by 37% after transfer under unpolluted conditions, especially between 0 and 3 days, suggesting that MTs play a predominant role in Cd depuration. The quantity of Cd sequestered by the MT fraction, after size-exclusion liquid chromatography, represents on average 40% of the total Cd bioaccumulated in the soft body of the molluscs, compared with only 4-9% for total accumulated Zn. This essential metal was principally bound to low molecular weight proteins, which represented 20% of total Zn. Furthermore, it was observed that MTs had a key role in Cd remanence in the bivalves, and it was also reported that other proteins or small peptides were involved in the depuration of Zn.

This paper details the results of perfusion experiments examining the accumulation of inorganic and methylmercury (Hg and MMHg) into the gill and intestine tissue of the blue crab, Callinectes sapidus. Additionally, the flux across the tissue to an internal medium, representative of crab tissue or haemolymph, during the perfusion was also measured. The accumulation and transfer processes were studied for each form by exposing the organs to a wide range of Hg and MMHg water concentrations, as well as a mixture of the two Hg forms. Experiments were also performed at different temperatures and in the presence of a metabolic inhibitor to assess the accumulation mechanisms. While the Hg levels bioaccumulated in the two organs were of the same order, the fluxes of Hg from the tissue to the internal medium were slightly higher in the intestine than in the gill. At low external concentrations, the uptake was very similar for both Hg forms, but as exposure pressure increased, inorganic Hg uptake slowed whereas MMHg uptake increased linearly. The results from the perfusion experiments with a mixture of inorganic Hg and MMHg show that while these two forms of Hg do share common uptake pathways, there is also independent uptake. The temperature and inhibition experiments with ouabain, a Na(+)K(+)ATPase inhibitor, show that accumulation is at least partially energy dependent. Overall, the results suggest that there is more than one mechanism of accumulation for both Hg forms. Finally, as accumulation of Hg and MMHg into these tissues was similar, these results contrast with the literature assertion that the enhanced bioaccumulation of MMHg over inorganic Hg is a result of MMHg being more readily transported across the gut membrane.

Using the perfusion method, we compared the accumulation and flux of inorganic mercury (Hg) and methylmercury (CH(3)Hg) across the gills and intestine of the blue crab, Callinectes sapidus. The accumulation and transfer processes were studied for each form by exposing the organs in the presence of specific ligands and other metals. While binding of Hg and CH(3)Hg to organic ligands reduced the rate of uptake in most instances, the differences in accumulation could not be explained only in terms of passive diffusive uptake. Thus, it appears that Hg and CH(3)Hg accumulation is dominated by ligand exchange or facilitated transport processes. Exposure of the gills and intestine in the presence of a suite of metals and metalloids showed that inorganic Hg and CH(3)Hg uptake was largely by different mechanisms to that of the other elements, as there was little interaction in terms of uptake rate. Overall, the results of this study suggest that inorganic Hg and CH(3)Hg uptake into the gills and intestine of this invertebrate is by a variety of pathways, both active and passive.

Objective: It is well established that T cells are effector cells in graft-vs-host disease (GVHD), yet the contribution of graft monocytes is less well characterized. Therefore, monocytes in cord blood (CB) and granulocyte colony-stimulating factor-mobilized apheresis products (G-AP), two stem cell grafts associated with reduction of acute and chronic GVHD and relative reduction of acute GVHD, respectively, were compared phenotypically and functionally., Materials and Methods: The frequencies, phenotypes, and pinocytosis activities of monocytes from CB and G-AP were determined by flow cytometry and their allostimulatory potential in a primary mixed leukocyte reaction., Results: G-AP contained significantly more monocytes than CB (24.9% +/- 7.1% vs 8.8% +/- 1.5% CD14+ and 62.4 +/- 27.5 x 10(6) vs 0.9 +/- 0.2 x 10(6) CD14+ cells/mL). Monocytes from both sources revealed similar phenotypes. They expressed CD4, CD11a, CD11b, CD11c, CD18, CD32, CD33, CD45R0, CD48, CD50, CD54, CD58, CD64, CD86, CD102, CD116, CD123, and HLA-DR; showed no expression of CD1a and CD83; and weak expression of CD16, CD45RA, and CD80. The levels of CD80 and CD86 expression were comparable; however, in contrast to G-AP monocytes, CB monocytes lacked CD40. There was no difference in pinocytosis activity and allostimulatory capacity of CB and G-AP monocytes., Conclusions: Monocytes in CB and G-AP are phenotypically and functionally comparable. The only difference observed is the lack of CD40 on CB monocytes.

Concentrations of mercury (Hg), methylmercury (MMHg), arsenic (As), selenium (Se), and cadmium (Cd) were measured in atmospheric deposition, stream water, and biota in two streams in western Maryland. Overall, concentrations were slightly higher in the water of the lower pH Herrington Creek tributary (HRCT). Bioaccumulation factors were also higher for HRCT compared to Blacklick Run (BLK). MMHg concentrations in biota increased with trophic level and essentially all the Hg was as MMHg in predatory insects and insectivorous/carnivorous fish. Thus, the overall trophic status of the organism was indicated by the %MMHg in its tissues. Levels of As, Se, Cd, and Hg, however, decreased with increasing trophic level. Adsorption of As to the exoskeleton of invertebrates appears to be an important accumulation mechanism. MMHg was distributed evenly throughout crayfish and fish organs, whereas As, Se, Cd, and Hg were found in higher concentrations in detoxifying organs. Concentrations in biota in this study were somewhat elevated compared to other rural sites, but were less than those of point source-contaminated sites. Overall, as atmospheric inputs to the two watersheds were similar, the results of this study show the importance of water chemistry in determining the bioaccumulation of the metals and metalloids into insects. Subsequent transfer to higher trophic levels is related to both the ability of the organisms to depurate and the mode of accumulation, either directly from water or from food.

The impact of cadmium (Cd) and zinc (Zn) discharges related to an old zinc ore treatment facility in the Lot River (France) was investigated in four fish species (the chub: Leusciscus cephalus, the roach: Rutilus rutilus, the perch: Perca fluviatilis and the bream: Abramis brama). The organisms were sampled in four stations along the polymetallic contamination gradient. Cd and Zn analysis were carried out in five organs (gills, posterior intestine, liver, kidneys and skeletal muscle) in order to highlight the potential pathways of uptake, storage and elimination of metals. The results indicate a very strong Cd contamination in fish collected downstream from the metal source. The kidneys have the highest cadmium concentrations, but the gills and the intestine, as exchange organs, present the largest variations between the stations in close relation with the contamination gradient. Cd concentrations measured in the liver vary only slightly among the sampling stations. Unlike the trends observed for Cd, Zn levels in fish populations are strongly regulated and do not follow ambient Zn concentrations. The concentrations measured vary also according to fish species, for both Cd and Zn. This study shows that the trophic habits can explain the interspecific differences in Cd bioaccumulation. Zn levels observed for each species in non-contaminated populations also help to understand metal bioaccumulation patterns in polluted sites, suggesting that the determinism of interspecific differences is constitutive.

The present study evaluates blood GSHPx activity in 18 sheep flocks at range, to identify those seasons with the highest risk of selenium deficiency. Samples were taken from 1108 15-day-old lambs during the two usual lambing periods in this geographical area (autumn-winter and spring-summer). The overall mean values in the first period (146.69 +/- 3.41 i.u./g Hb) was higher than in the second one (107.50 +/- 3.53 i.u./g Hb). This may be explained by the special features of the climate in the Mediterranean area, which allow an optimum growth of grass from October to May. Therefore, the lambs born in spring-summer are from pregnancies in months when feeding is based only upon grazing. However, lambs born in autumn-winter comes from ewes gestating during the summer, when supplementation with cereal grains is given. As a conclusion, lambs born in spring-summer in this area are at higher risk to selenium-deficiency related disorders.

Burrowing mayfly nymphs (Hexagenia rigida) were exposed to naturally contaminated sediments collected from two stations along a metallic pollution gradient on the Lot River (France) using indoor microcosms. Bioaccumulation kinetics (0, 20, 40, and 60 days) of cadmium (Cd) and the combined effects of temperature (12, 18, and 24 degreesC) were evaluated by a complete experimental design, jointly with the analysis of growth rate of the nymphs, bioturbation, and total and dissolved Cd concentrations in the water column. Cadmium was transferred from the sediment to the organisms with uptake influenced by contamination levels of the sediments, exposure duration, and temperature. The two complementary criteria-Cd concentration and burden in the nymphs-clearly demonstrate the importance of the growth dilution on the quantification of Cd bioaccumulation at the whole organism level.

In October 1988, right-to-know legislation was introduced in Canada. This presented a technical and administrative challenge to the health care sector. With over 170 health care facilities in Manitoba to be brought into compliance, some large, some small, some rural, some urban, a cooperative approach was needed. A labor-management steering committee with representatives from a cross-section of facilities as well as the various health care unions was formed to design and implement a train-the-trainer program. A small-group, highly participatory modular program was developed with input from all parties, and delivered across the province by trainers selected jointly by labor and management. The program achieved its goal of assisting member facilities to implement the legislation. Follow-up surveys and discussions with health care workers showed improved understanding of labelling requirements, material safety data sheet interpretation, and requirements for hazard control. This first bipartite program empowered the health care workforce to use its newly acquired right-to-know, and has provided the incentive to implement other cooperative safety and health programs.

The haematological parameters of healthy great bustards (Otis tarda L.) have been determined. The values obtained were red cell count (3.0 x 10(12) +/- 0.2 x 10(12/)1), white cell count (33.0 x 10(9) +/- 2.6 x 10(9)/1), haematocrit value (0.51 +/- 0.01 1/1), haemoglobin (13.0 +/- 0.3 g/dl), mean corpuscular volume (178.7 +/- 12.5 fl), mean cell haemoglobin concentration (25.0 +/- 0.6 g/dl), mean corpuscular haemoglobin (42.5 +/- 3.2 pg), differential white cell count: heterophils (22.5 x 10(9) +/- 0.7 x 10(9)/1), lymphocytes (6.0 x 10(9)+/-0.7 x 10(9)/1), eosinophils (2.7 x 10(9) +/- 0.3 x 10(9)/1) and monocytes (1.8 x 10(9)+/-0.2 x 10(9)/1).