Imbalanced secondary mucosal antioxidant response in inflammatory bowel disease

Intestinal mucosal damage in the inflammatory bowel diseases (IBD) Crohn's disease (CD) and ulcerative colitis (UC) involves reactive oxygen metabolites (ROMs). ROMs are neutralized by endogenous antioxidant enzymes in a carefully balanced two-step pathway. Superoxide dismutases (SODs) convert superoxide anion to hydrogen peroxide (H(2)O(2)), which is subsequently neutralized to water by catalase (CAT) or glutathione peroxidase (GPO). Remarkably changed expression levels of the three isoforms of SOD in paired non-inflamed and inflamed mucosae from CD and UC patients have been previously reported in comparison to normal control mucosa. Most notable was the strong up-regulation of Mn-SOD in inflamed epithelium. It was hypothesized that in order to provide optimal protection against ROM-mediated damage, these changes should be coordinately counterbalanced by an increased H(2)O(2)-neutralizing capacity. Therefore, the same tissue samples were used to assess the levels, activities, and/or localization of the most prominent mucosal H(2)O(2)-related antioxidants CAT, GPO, glutathione (GSH), myeloperoxidase (MPO), and metallothionein (MT). Quantitative measurements showed that in both CD and UC patients, intestinal inflammation was associated with increased activities of CAT, GPO, and MPO, whereas the mucosal GSH content was unaffected and the concentration of MT was decreased. Despite this overall increase in mucosal H(2)O(2)-metabolizing enzyme capacity, immunohistochemical analysis revealed a differentially disturbed antioxidant balance in IBD epithelium and lamina propria. In the lamina propria, the risk of direct H(2)O(2)-mediated damage seemed to be restrained by the increasing numbers of CAT- and MPO-positive monocytes/macrophages and neutrophils that infiltrated the inflamed areas. On the other hand, MPO overexpression might increase the lamina propria levels of hypochlorous acid, a stable ROM with multiple pro-inflammatory effects. In the epithelium, the number of cells that expressed CAT remained unchanged during inflammation and GPO was found in only a very low and constant number of epithelial cells. In addition, the inflamed epithelium displayed decreased expression of the hydroxyl radical (OH(*)) scavenger MT. In view of the high epithelial SOD levels in inflamed IBD epithelium, it is speculated that the efficient removal of excess H(2)O(2) is hampered in these cells, thereby increasing not only the risk of detrimental effects of H(2)O(2) directly, but also those of its extremely reactive derivatives such as OH(*). Taken together, the results suggest an imbalanced and inefficient endogenous antioxidant response in the intestinal mucosa of IBD patients, which may contribute to both the pathogenesis and the perpetuation of the inflammatory processes.     

Detection and characterization of diarrheagenic Escherichia coli from young children in Hanoi, Vietnam

Diarrhea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. Escherichia coli is an emerging agent among pathogens that cause diarrhea. The development of a highly applicable technique for the detection of different categories of diarrheagenic E. coli is important. We have used multiplex PCR by combining eight primer pairs specific for enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli, enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC). This facilitates the identification of five different categories of diarrheagenic E. coli from stool samples in a single reaction simultaneously. The prevalences of diarrheagenic E. coli were 22.5 and 12% in the diarrhea group and the control group, respectively. Among 587 fecal samples from Vietnamese children under 5 years of age with diarrhea, this technique identified 132 diarrheagenic E. coli strains. This included 68 samples (11.6%) with EAEC, 12 samples (2.0%) with EIEC, 39 samples (6.6%) with EPEC, and 13 samples (2.2%) with ETEC. Among the 249 age-matched controls, 30 samples were positive for diarrheagenic E. coli. The distribution was 18 samples (7.2%) with EAEC, 11 samples (4.4%) with EPEC, and 1 sample (0.4%) with ETEC.     

The effect of light deprivation on the electro retinogram of the guinea pig

Summary The b-wave in the ERG of guinea pigs born and reared in darkness for three months is considerably smaller than that in animals of the same age reared under normal circumstances.Exposure to room illumination for ten days greatly restores the ERG. The ERG in four days old light deprived animals is normally developed. A three months light deprivation period causes a relatively small effect in normally raised adult animals.From these experiments it is concluded that the initial ERG development in the guinea pig is not affected by light deprivation. However, once developed the ERG in new born animals is more vulnerable to prolonged light deprivation than that in adult ones.     

A novel tracheal tissue connector for fixation of laryngeal prostheses

A tissue connector (TC), basically consisting of a ring that will be integrated into the trachea, is under development to study the fixation of laryngeal prostheses. Two experiments have been performed to test the TC in goats. In experiment 1, a polypropylene mesh was implanted around the trachea. The meshes were explanted after 6 and 12 weeks. In experiment 2, the actual TC consisted of two titanium rings (inner ring and outer ring) executed as quarter rings, fixed on each other, and a polypropylene mesh like a sandwich in between. The titanium inner ring was implanted between two tracheal rings thus penetrating the trachea with the mesh around the trachea and the fixed titanium outer ring on the outside of the trachea. The TCs were removed after 12 weeks. Experiment 1 showed that the mesh was entirely infiltrated by host tissue. Inflammatory cells and high vascularisation were observed in 3 of 4 implants. However, in experiment 2, the mesh was completely incorporated by mature connective tissue without inflammation reaction. At some areas, deposition of cartilage tissue was observed. In conclusion, the TC was firmly embedded in the trachea thus being appropriate for its intended use.     

Correlation between semen parameters and sperm aneuploidy rates investigated by fluorescence in-situ hybridization in infertile men

Spermatozoa from 32 infertile patients and 13 controls with normal semen parameters were analysed using dual and triple colour fluorescence in-situ hybridization (FISH) techniques, in order to investigate the rates of aneuploidy for chromosomes 13, 18, 21, X and Y. The patients were divided into three groups according to their karyotypes or the karyotypes of their offspring: 15 were infertile men with abnormal semen parameters and normal karyotypes (group 1), 13 were infertile men with abnormal karyotypes and normal or abnormal semen (group 2) and four were infertile men with abnormal semen and normal karyotypes but whose wives conceived a child (or a fetus) with a numerical chromosomal abnormality through an intracytoplasmic sperm injection cycle (group 3). Patients with abnormal semen parameters showed a significantly higher aneuploidy rate for the investigated chromosomes in their spermatozoa compared to controls (P < 0.005). Our data suggest the presence of a correlation between poor semen parameters and an increase in aneuploidy rate of chromosomes 13, 18, 21, X and Y in spermatozoa (r = -0.81071, P < 0.002); therefore the risk of a chromosomal aneuploidy in spermatozoa seems to be inversely correlated to sperm concentration and total progressive motility. Patients with abnormal karyotypes showed a higher incidence of diploidy and chromosomal aneuploidies compared to controls (P < 0.002). This strongly suggests the presence of an interchromosomal effect of the cytogenetic rearrangement. Men who fathered a child with an abnormal karyotype through intracytoplasmic sperm injection did not present a higher aneuploidy rate for the investigated chromosomes in spermatozoa compared to patients with infertility due to a similar male factor but showed higher incidence of chromosomal aneuploidy compared to normal controls.     

Coping and extreme response tendency in duodenal ulcer patients.

In this study we examined problem- and emotion-focused coping in samples of 30 duodenal ulcer (DU) patients and 30 matched healthy controls. Coping processes were assessed for two stressful situations, viz, an interpersonal conflict and a difficult task or job. The results indicated that DU patients and controls did not differ in terms of preferred coping strategies: irrespective of type of stressor, no differences were found between the two samples, neither in terms of a more general inclination toward problem- or emotion-focused coping, nor in terms of separate, more fine-grained coping mechanisms. Furthermore, rating extremity was studied in both samples. It was found that DU patients have a tendency to endorse extreme positive responses ("Very characteristic of me") more often than controls. The latter finding is discussed in terms of competing explanations: (a) higher polarizing tendencies of DU patients vs. (b) higher meaningfulness of the questionnaire items for DU patients. Specific directions for future research are described.     

Reduction of Diagnostic Window by New Fourth-Generation Human Immunodeficiency Virus Screening Assays

In order to reduce the diagnostic window between the time of human immunodeficiency virus (HIV) infection and laboratory diagnosis, new screening enzyme-linked immunosorbent assays (ELISAs) which permit the simultaneous detection of HIV antigen and antibody have been developed. Two fourth-generation assays, HIV DUO (Biomérieux) and HIV Combi (Boehringer Mannheim), for the combined detection of HIV antigen and antibody, were compared with a third-generation assay (HIV-1/HIV-2 3rd Generation Plus enzyme immunoassay [EIA]; Abbott) and a p24 antigen test (HIV-1 Ag monoclonal; Abbott). A total of 17 seroconversion panels, 15 cell culture supernatants infected with different HIV type 1 (HIV-1) subtypes, and 255 potentially cross-reactive serum samples were tested. Ten seroconversions were detected an average of 8.1 days earlier with HIV DUO and 7.5 days earlier with HIV Combi than with the third-generation ELISA. Overall, in the 17 seroconversion panels tested, HIV DUO detected HIV-1 infection an average of 4.8 days and HIV Combi detected infection an average of 4.4 days earlier than HIV-1/HIV-2 3rd Generation Plus EIA. HIV antigen was detected with HIV DUO and HIV Combi in all of the 15 cell culture supernatants infected with different HIV-1 subtypes, including subtype O. With fourth-generation assays, considerably fewer false-positive results (n = 4 to 6) were obtained, in comparison with the third-generation EIA (n = 18). Fourth-generation assays permit an earlier diagnosis of HIV infection than third-generation antibody screening assays through the detection of p24 antigen, which may be present in serum samples from individuals with recent HIV infection prior to seroconversion.     

Lung function measurements over 21 days shiftwork in steelworkers from a strandcasting department

On the assumption that short term changes in lung function may reflect the potential for a long term decline the evolution of lung function indices in 25 steelworkers from a strandcasting department and in 11 comparable steelworkers not exposed to dust was investigated over an almost uninterrupted 21 day working period and over three different workshifts. The mean total dust level in the strandcasting department, assessed by personal sampling, was 11.8 mg/m3. All subjects were examined at the beginning, in the middle, and at the end of their first (day 1) morning shift (0600 to 1400), their last (day 14) afternoon shift (1400 to 2200), and their last (day 21) night shift (2200 to 0600). Indices measured were vital capacity (VC), forced expiratory volume in one second (FEV1) and in three seconds (FEV3), forced expiratory flow over the middle half of the forced vital capacity (FEF25-75), peak expiratory flow rate (PEFR), the slope of the N2 plateau (delta N2) and the closing volume (CV) of the single breath oxygen test. Differences in indices between initial values (0600 on day 1) and final values (0500 on day 21) were not significant in the control group (except delta N2 which became lower); in the casting group there were significant (p less than 0.05) decreases in FEF25-75 and FEV3, but these decreases were not significantly greater than in the control group. Lung function changes were not significant in either group over the morning shift. During the afternoon there were significant decreases in spirometric indices in the casting group, with no significant decreases in the control group, but the interactions between exposure and time were generally not significant. During the night shift, however, the decreases in FEV1 and FEF25-75 observed in the strandcasting group were significantly more pronounced than in the control group. The single breath test, which many subjects failed to perform correctly on each occasion, showed no significant changes in closing volumes, and an "improvement" of delta N2 over the morning and the night shift in the control but not the exposed subjects needs to be interpreted with caution. The more pronounced decrease in spirometric indices, suggestive of slight airways obstruction, found over the night shift in the strandcasting workers is attributed to their working environment.     

Lung function measurements over 21 days shiftwork in steelworkers from a strandcasting department.

On the assumption that short term changes in lung function may reflect the potential for a long term decline the evolution of lung function indices in 25 steelworkers from a strandcasting department and in 11 comparable steelworkers not exposed to dust was investigated over an almost uninterrupted 21 day working period and over three different workshifts. The mean total dust level in the strandcasting department, assessed by personal sampling, was 11.8 mg/m3. All subjects were examined at the beginning, in the middle, and at the end of their first (day 1) morning shift (0600 to 1400), their last (day 14) afternoon shift (1400 to 2200), and their last (day 21) night shift (2200 to 0600). Indices measured were vital capacity (VC), forced expiratory volume in one second (FEV1) and in three seconds (FEV3), forced expiratory flow over the middle half of the forced vital capacity (FEF25-75), peak expiratory flow rate (PEFR), the slope of the N2 plateau (delta N2) and the closing volume (CV) of the single breath oxygen test. Differences in indices between initial values (0600 on day 1) and final values (0500 on day 21) were not significant in the control group (except delta N2 which became lower); in the casting group there were significant (p less than 0.05) decreases in FEF25-75 and FEV3, but these decreases were not significantly greater than in the control group. Lung function changes were not significant in either group over the morning shift. During the afternoon there were significant decreases in spirometric indices in the casting group, with no significant decreases in the control group, but the interactions between exposure and time were generally not significant. During the night shift, however, the decreases in FEV1 and FEF25-75 observed in the strandcasting group were significantly more pronounced than in the control group. The single breath test, which many subjects failed to perform correctly on each occasion, showed no significant changes in closing volumes, and an "improvement" of delta N2 over the morning and the night shift in the control but not the exposed subjects needs to be interpreted with caution. The more pronounced decrease in spirometric indices, suggestive of slight airways obstruction, found over the night shift in the strandcasting workers is attributed to their working environment.