Evaluation of the chemical residue monitoring in animal-derived products in Switzerland

This paper evaluates whether the Swiss monitoring programme for foreign substances in animal products fulfils basic epidemiological quality requirements, and identifies possible sources of bias in the selection of samples. The sampling was analysed over a 4-year period (2002-05). The sampling frame in 37 participating abattoirs covered 51% of all slaughtered pigs, 73% of calves, 68% of beef and 36% of cows. The analysis revealed that some sub-populations as defined by the region of origin were statistically over-represented while others were under-represented. The programme that is in accordance with European Union requirements contained some relevant bias. Patterns of under-sampled regions characterized by management type differences were identified. This could lead to an underestimate of the number of contaminated animals within the programme. Although the current sampling was stratified and partially risk-based, its efficiency could be improved by adopting a more targeted approach.

Survival of clostridium perfringens during simulated transport and stability of some plasmid-borne toxin genes under aerobic conditions

Clostridium perfringens is a pathogen of great concern in veterinary medicine, because it causes enteric diseases and different types of toxaemias in domesticated animals. It is important that bacteria in tissue samples, which have been collected in the field, survive and for the classification of C. perfringens into the correct toxin group, it is crucial that plasmid-borne genes are not lost during transportation or in the diagnostic laboratory. The objectives of this study were to investigate the survival of C. perfringens in a simulated transport of field samples and to determine the stability of the plasmid-borne toxin genes cpb1 and etx after storage at room temperature and at 4 degrees C. Stability of the plasmid-borne genes cpb1 and etx of C. perfringens CCUG 2035, and cpb2 from C. perfringens CIP 106526, JF 2255 and 6 field isolates in aerobic atmosphere was also studied. Survival of C. perfringens was similar in all experiments. The cpbl and etx genes were detected in all isolates from samples stored either at room temperature or at 4 degrees C for 24-44 h. Repeated aerobic treatment of C. perfringens CCUG 2035 and CIP 106526 did not result in the loss of the plasmid-borne genes cpb1, cpb2 or etx. Plasmid-borne genes in C. perfringens were found to be more stable than generally reported. Therefore, C. perfringens toxinotyping by PCR can be performed reliably, as the risk of plasmid loss seems to be a minor problem.

Interactions of atmospheric deposition with coniferous canopies in Estonia

Throughfall and open field bulk precipitation were measured at three coniferous sites during 1995-2002 in the framework of ICP Integrated Monitoring and at five coniferous sites during 1996-2002 in the framework of ICP Forests (Level II). The coniferous canopies acted as a sink for nitrate and ammonium and as a source for base cations: Ca(2+), Mg(2+) and K(+). The estimated share of SO(4)-S dry deposition from total deposition was 1.5-4 times higher for dormant period compared to growing period. During the study period average annual throughfall and bulk deposition of SO(4)-S decreased significantly, 2.8 and 2.3 times, respectively. Throughfall enrichment with base cations increased in the order Mg < Na < Ca < K. Using Na as a tracer ion, average dry deposition and canopy leaching were calculated. Leaching was the dominant process for TF enrichment by potassium. Leaching of base cations occurred during growing as well as dormant period. The calculated internal flux of Ca(2+) and Mg(2+) varied in the range of 0.6-2.0 and 0.6-1.2 kg ha(-1) per year in spruce and pine stands, respectively. The internal circulation of K(+) was significantly higher (8.9-10.9 kg ha(-1) per year) in spruce stands than in pine stands (2.7-4.4 kg ha(-1) per year).

Outbreaks of infectious keratoconjunctivitis in alpine chamois and ibex in Switzerland between 2001 and 2003

Five outbreaks of infectious keratoconjunctivitis (ikc) affecting alpine chamois and ibex in the western and central Swiss Alps were recorded in 2001 to 2003. Mycoplasma conjunctivae was identified from conjunctival swabs by means of a nested pcr in 27 of the 28 chamois tested. The outbreaks occurred in an area covering 1590 km(2). Deep valleys acted as a barrier to the spread of the disease. A total of 409 chamois and 33 ibex with clinical signs of ikc were reported. Most of the chamois were shot, primarily because they were blind or in poor general body condition. Almost a quarter were observed alive, and 16.9 per cent died as a result of ikc. Many of the affected animals were juveniles, and more females than males died of ikc. The disease was more common during the summer and autumn. The chamois affected by ikc were found at altitudes between 550 and 3200 m. The estimated overall mortality was less than 5 per cent, but more than 20 per cent may have died locally. Ibex affected by ikc were recorded in only two outbreaks. In six places, ibex with clinical signs of ikc were found before the first affected chamois appeared in the same area.

Antibodies to Aqx toxin of Actinobacillus equuli in horses and foals

Actinobacillus equuli is found in the normal oral flora of horses, but has been associated with several diseases, and particularly with the usually fatal septicaemia in neonatal foals which is thought to be associated with a failure of the passive transfer of immunoglobulins via the colostrum. The Aqx protein of A equuli, belonging to the RTX family of pore-forming toxins, is also cytotoxic to horse lymphocytes. The presence of antibodies to Aqx was investigated in sera from individual horses from different regions; the sera from adult horses and foals 24 hours after birth reacted with Aqx, and sera from foals sampled shortly after an intake of colostrum also reacted with Aqx, but sera from foals taken before an intake of colostrum did not react with Aqx.

Aeromonas sobria, a causative agent of disease in farmed perch, Perca fluviatilis L

Significant numbers of perch, Perca fluviatilis, raised on a pilot fish farm in Switzerland presented focal skin lesions on the lateral sides and fin rot. Mortality rates reached levels of up to 1% of the total fish on the farm per day. Virtually pure cultures of Aeromonas sobria were isolated from the liver, kidney, spleen and skin lesions of affected fish. Aeromonas sobria isolated from the farmed perch had a haemolytic effect on sheep and trout erythrocytes, autoaggregated, was cytotoxic for cultured fish cells and possessed genes involved in type III protein secretion. Experimental infection of naive perch with a single colony isolate of A. sobria from an affected farm fish resulted in the development of clinical signs identical to those seen on the farm. The results indicate that A. sobria can act as a primary pathogen of perch.

Vitamin D receptor gene polymorphisms and association with type 2 diabetes mellitus in a Polish population

Vitamin D plays an important role in insulin secretion. There is also evidence that this steroid may influence the insulin sensitivity. Thus genes involved in its metabolic pathway have been regarded as good candidates for type 2 diabetes mellitus (T2DM). One of them is vitamin D receptor gene (VDR). Its multiple polymorphisms have been examined for the association with T2DM in several populations. Those studies did not provide clear answers about the role of VDR in this disease. The aim of the study was to search for the association of FokI, ApaI, BsmI, and TaqI polymorphisms of VDR gene with T2DM in a Polish population using a case-control study design. Overall, 548 individuals were examined: 308 T2DM patients and 240 control individuals. The study groups were genotyped for VDR FokI, ApaI, BsmI, and TaqI variants using the restriction fragment length polymorphism (RFLP) method. Since variants of ApaI, BsmI, and TaqI polymorphisms were in very strong linkage disequilibrium, three loci haplotypes could be assigned to phase-unknown individuals with a high degree of confidence. Differences in allele, genotype, haplotype, and haplotype combination distribution between the groups were examined by chi2 test. The VDR allele frequencies for T2DM patients and controls were as follows: FokI-F/f - 53.4 %/46.6 % vs. 55.2 %/44.8 %, BsmI-B/b - 34.4 %/65.6 % vs. 37.5 %/62.5 %, ApaI-A/a - 47.9 %/52.1 % vs 50.9 %/49.1 %, TaqI-T/t - 67.6 %/32.4 % vs. 62.7 %/37.3 %, respectively. There was no difference between the groups in allele frequency. Similarly, distribution of genotypes, three locus BsmI/ApaI/TaqI haplotypes and their combinations were similar in the groups. In conclusion, our study did not provide evidence for the association of four examined VDR polymorphisms with T2DM in a Polish population. We postulate that to fully determine whether the sequence differences in VDR gene are susceptibility variants for T2DM, additional studies in different populations are required in a large study group.

Use of recombinant ApxIV in serodiagnosis of Actinobacillus pleuropneumoniae infections, development and prevalidation of the ApxIV ELISA

Actinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia, which causes worldwide severe losses in pig farming. The virulence of the 15 serotypes of A. pleuropneumoniae is mainly determined by the three major RTX toxins ApxI, ApxII and ApxIII, which are secreted by the different serotypes in various combinations. A fourth RTX toxin, ApxIV, is produced by all 15 serotypes only during infection of pigs, but not under in vitro conditions. Pigs infected with A. pleuropneumoniae show specific antibodies directed against ApxIV. In contrast, antibodies against the other three toxins ApxI, ApxII and ApxIII are also found in pigs free of A. pleuropneumoniae. The antibodies to the three latter might result from other, less pathogenic Actinobacillus species such as A. rossii and A. suis. We used a recombinant protein based on the N'-terminal part of ApxIV to serologically detect A. pleuropneumoniae infections in pigs by immunoblot analysis. The analysis of sera of experimentally infected pigs revealed that ApxIV-immunoblots detected A. pleuropneumoniae infections in the second to third week post infection. We developed an indirect ELISA based on the purified recombinant N'-terminal moiety of ApxIV. The analysis of sera from pigs that were experimentally or naturally infected by A. pleuropneumoniae, and of sera of pigs that were free of A. pleuropneumoniae, revealed that the ELISA had a specificity of 100% and a sensitivity of 93.8%. The pre-validation study of the ApxIV-ELISA revealed that the latter was able to detect A. pleuropneumoniae-positive herds, even when clinical and pathological signs of porcine pleuropneumonia were not evident. Pigs vaccinated with a subunit vaccine Porcilis App were serologically negative in the ApxIV-ELISA.

Objective measurement of hyperactivity, impulsivity, and inattention in children with hyperkinetic disorders before and after treatment with methylphenidate

PURPOSE

The purpose of this study was to investigate whether values of the respective parameters of the OPTAx test dependently differ due to the medication with methylphenidate (MPH) in children with hyperkinetic disorders (HD) suffering from hyperactivity, impulsivity, and attention deficits.

METHODS

The OPTAx test is an infrared motion analysis to record the movement pattern during a continuous performance test. We tested 25 children between 6 and 12 years with HD (ICD-10: F90.0 or F90.1) before and after treatment with MPH. The parameters under investigation were activity (microevents and spatial scaling), impulsivity (errors of commission), and attentiveness (accuracy and variability). For statistical analysis a one-tailed matched pairs test (adj. p = 0.01) was conducted to discriminate differences found from those occurred at random. A post hoc partial correlation of absolute differences in the respective parameters and the daily dose of MPH (adj. for BMI) was performed if p < 0.01.

RESULTS

Statistically significant results were found for microevents, spatial scaling, errors of commission, accuracy, and variability. The partial correlation showed significant results for microevents and variability.

CONCLUSION

The mean pre-post changes found in all parameters investigated consistently correspond with benefits desired from medication with MPH in children with HD. Absolute differences in microevents and variability seem to depend on the daily dose of MPH after adjustment for BMI.

Native protein glycoxidation and aging

Structural and functional alterations of proteins are observed during aging. Glycation of long half-life proteins, involving reducing carbohydrates, leads to the formation of intra and intermolecular cross-links and the production of free radicals. These processes depend on the amount of glucose available and on molecular oxygen which contributes to the production of free radicals. These processes are observed without dysfunction of carbohydrate metabolism and progress with age. However, whether this process is a primary cause or a consequence of aging remains a question of debate. Prevention of excessive glycoxidation could be a goal of recommendations designed to control the tissular alterations occurring in aging.

Changes in glycation of fibrous type I collagen during long-term in vitro incubation with glucose

The course of glycation of calf skin fibrous type I collagen was monitored in vitro under physiological conditions during an 8-week incubation period in order to take into account the long half-life of this protein. The formation of glycated compounds was measured by determining fructosamine, pentosidine, and carboxymethyllysine content. The incubation conditions were as physiological as possible in sterile saline phosphate buffer, except glucose concentration. With incubation medium containing 200 mmol glucose, fibrous collagen underwent solubilization; in addition an increase in fructosamine, pentosidine, and carboxymethyllysine content in both solubilized and remaining insoluble collagen was noticed. There was a spontaneous, restricted, and time-dependent native glycated state of collagen; high concentration glucose enhanced the formation of glycated compounds and induced changes in solubility and glycoxidated products. The production of pentosidine during incubation without glucose should be considered as an event resulting from the initial fructosamine. Whereas the production of carboxymethyllysine during long-term incubation with glucose provided indirect proof of an additional oxidative process after early glycated product formation. These experimental observations provide insight into the in vivo context of advanced glycation end product formation in chronic hyperglycemia and aging.

In vitro glycoxidation of insoluble fibrous type I collagen: solubilization and advanced glycation end products

The deleterious effects of glycoxidation are dependent on the half-life of proteins. Collagen, the main component of extracellular matrices, is a long live protein and thus may be sensitive to the glycoxidation process. We incubated calf skin fibrous type I collagen in PBS at 37 degrees C with glucose. The fibrous type I collagen was solubilized and an increase in the amount of advanced glycation end products of the solubilized fraction was observed. As there was no bacterial contamination and no proteolytic activities in the incubation medium, the solubilization of fibrous type I collagen is probably due to the speculative production of the free radicals in our experimental conditions. To test this hypothesis, fibrous type I collagen was incubated in PBS with AAPH (2,2'azo-bis 2-aminodinopropane) a free radicals generator. AAPH induced a dramatic and dose dependent solubilization of fibrous type I collagen.

Immunohistochemical localization of Clostridium perfringens beta2-toxin in the gastrointestinal tract of horses

Clostridia-associated intestinal disease in horses was generally reported to be due to infection with Clostridium perfringens type A, which harbors the cpa-encoded alpha-toxin. A recent study demonstrated a high incidence of beta2-toxigenic C. perfringens in horses suffering or dying from typhlocolitis, suggesting that this novel type of C. perfringens might play an important role in typhlocolitis and possibly other equine intestinal diseases. A retrospective study was conducted to assess the presence of the beta2-toxin in tissues of the equine gastrointestinal tract. Monospecific polyclonal antibodies against recombinant beta2-toxin were produced in rabbits and used to demonstrate the beta2-toxin in sections of the gastrointestinal tract by immunohistochemical methods. Sections from 69 horses were stained and beta2-toxin was observed immunohistochemically in 40 animals. Sections from the stomach, small intestine, and large intestine were positive. Immunopositivity for beta2-toxin was significantly associated with presence of beta2-toxigenic bacteria. This investigation demonstrates local production of beta2-toxin and suggests that immunohistochemistry using antitoxin antibodies represents a useful diagnostic method in those cases where isolation of bacteria and polymerase chain reaction typing is not feasible. Although the association between the presence of beta2-toxin and development of gastrointestinal disease in horses remains uncertain, the findings of this study indicate that the potential causal relationship warrants further investigation.

[Pheromones: an underestimated communication signal in humans]

The pheromones are molecules, mainly aliphatic acids, with or without perceptible odor, recognized by specific receptors, the stimulation of which induces neuroendocrine reactions and affects the individual behavior. Olfactory receptors are underexpressed in human, 70 % of genes have become nonfunctional pseudogenes. But the remaining function was tested and is able to induce emotional reactions corresponding to a non-verbal signal of social interactions. In the present study, we review the actual knowledge on the olfactory receptors. They belong to the G-protein-coupled-receptors. Their signal is transduced to the hypothalamic-pituitary-gonadal axis. Some HLA-based olfactory cues are shown with reference to recent experiments. The pathophysiological hypotheses are considered with respect to studies in anorexia nervosa and Alzheimer' disease.

Non-pathogenic Actinobacillus isolates antigenically and biochemically similar to Actinobacillus pleuropneumoniae: a novel species?

Two unusual Actinobacillus isolates were recovered from pigs with no clinical signs, no lesions and no history of swine pleuropneumonia. Two representative strains (9953L55 and 0347) analyzed in this study were initially biochemically and antigenically identified as A. pleuropneumoniae serotypes 1 and 9, respectively, by traditional identification methods. Both strains presented, however, negative results with three A. pleuropneumoniae-specific PCR tests and revealed in particular the absence of the apxIV toxin genes. However, both strains produced and secreted ApxII toxin although they only harbored the toxin genes apxIICA, which is an uncommon feature for any of the known A. pleuropneumoniae serotypes. Upon experimental inoculation of pigs, these strains proved to be totally non-pathogenic. Animals infected with one of the strains produced antibodies that cross-react with A. pleuropneumoniae serotypes 1-9-11-specific LC-LPS ELISA. Phylogenetic analysis based on 16S rRNA gene sequence analysis revealed that these strains form a separate phylogenetic group that is distinct from other Actinobacillus species and is particularly different from A. pleuropneumoniae.

Host cell specific activity of RTX toxins from haemolytic Actinobacillus equuli and Actinobacillus suis

We assessed and compared host cell specificity of the haemolytic and cytotoxic activity of the RTX toxins from Actinobacillus equuli, an equine pathogen, and Actinobacillus suis, which is pathogenic for pigs. The two bacterial species are closely related, phenotypically as well as phylogenetically, sharing the same 16S rRNA gene sequence. Both species contain specific protein toxins from the family of pore-forming RTX toxins, however, the two species differ in their RTX toxin profiles. Haemolytic A. equuli contains the operon for the Aqx toxin, whereas A. suis harbours genes for ApxI and ApxII. We tested the toxic activity of the corresponding proteins on erythrocytes as well as on lymphocytes isolated from horse and pig blood. The strength of the haemolytic activity for each of the toxins was independent of the origin of erythrocytes. When testing cytotoxic activity, the Aqx protein showed a higher toxic effect for horse lymphocytes than for porcine lymphocytes. On the other hand, ApxI and ApxII showed a strong cytotoxic effect on porcine lymphocytes and a reduced toxicity for horse lymphocytes; the toxicity of ApxII was generally much lower than ApxI. Our results indicate a host species specificity of the toxic activity of RTX toxins Aqx of A. equuli and ApxI and ApxII of A. suis.

PCR detection of virulence genes in Yersinia enterocolitica and Yersinia pseudotuberculosis and investigation of virulence gene distribution

PCR-based assays were developed for the detection of plasmid- and chromosome-borne virulence genes in Yersinia enterocolitica and Yersinia pseudotuberculosis, to investigate the distribution of these genes in isolates from various sources. The results of PCR genotyping, based on 5 virulence-associated genes of 140 strains of Y. enterocolitica, were compared to phenotypic tests, such as biotyping and serotyping, and to virulence plasmid-associated properties such as calcium-dependent growth at 37 degrees C and Congo red uptake. The specificity of the PCR results was validated by hybridization. Genotyping data correlated well with biotype data, and most biotypes resulted in (nearly) homogeneous genotypes for the chromosomal virulence genes (ystA, ystB, and ail); however, plasmid-borne genes (yadA and virF) were detected with variable efficiency, due to heterogeneity within the bacterial population for the presence of the virulence plasmid. Of the virulence genes, only ystB was present in biotype 1A; however, within this biotype, pathogenic and apathogenic isolates could not be distinguished based on the detection of virulence genes. Forty Y. pseudotuberculosis isolates were tested by PCR for the presence of inv, yadA, and lcrF. All isolates were inv positive, and 88% of the isolates contained the virulence plasmid genes yadA and lcrF. In conclusion, this study shows that genotyping of Yersinia spp., based on both chromosome- and plasmid-borne virulence genes, is feasible and informative and can provide a rapid and reliable genotypic characterization of field isolates.

[Biochemical and pharmacological check-up in emergency orientation]

Biochemical and pharmacological tests usually prescribed in casualty department were reviewed taking into account their physiological significance and predictive value : ions, total proteins, carbohydrate and nitrogenous metabolites, enzymes, tissue markers, pharmacological drugs. Few blood components were kept with the first intention, ideally with a turn around time below one hour: sodium, potassium, chloride, bicarbonate, total proteins, pCO2 and pO2, creatinine, glucose, ketone compounds, calcium, bilirubin, transaminases, lipase, C-reactive protein, myoglobin, troponin, chorionic gonadotropin hormone. Those tests do not have to be systematically performed but prescribed only after the evaluation of pre-test probabilities by the clinician.

Production of matrix metalloproteinase 2 in fibroblast reaction to mechanical stress in a collagen gel

The reaction of fibroblasts to mechanical forces generated by fibroblasts themselves in anchored collagen lattices was studied. Fibroblasts were cast in collagen gels. Free retracted gels (RG) were compared with stressed gels (SG) in 3-day and 14-day experiments. As previously described, SG showed an increase in protein, mainly collagen, biosynthesis. Matrix metalloproteinases (pro-MMP-2 and MMP-2) were studied by zymography. Certain cell membrane components, integrin alpha(2) and phosphatidylserine, were studied by flow cytometry with antibodies against the integrin alpha(2) subunit and with annexin V binding. Mechanical stress stimulated production of pro-MMP-2 both in the short-term (3-day) and the longer term (14-day) cultures. However, the pro-enzyme was not more activated and there was no difference in the amount of MMP-2 between RG and SG. There was only an increase with time under both conditions. The stressed fibroblasts reacted early with an increase in the integrin alpha(2) subunit, but the stimulated cells disappeared from the 14-day cultures. The number of cells measured in terms of the amount of DNA decreased between day 3 and day 14, mainly in the SG due to cytolysis. This cell stress was related to an alteration in the plasma membrane detected by the annexin V marker.