Duplex real-time PCR detection of type III effector tccP and tccP2 genes in pathogenic Escherichia coli and prevalence in raw milk cheeses.

AIMS: To develop a duplex real-time PCR assay targeting enterohaemorrhagic Escherichia coli (EHEC) type III effector TccP/TccP2-encoding genes which are pivotal to EHEC-mediated actin cytoskeleton reorganization in human intestinal epithelial cells. METHODS AND RESULTS: The specificity of the assay was demonstrated with DNA from EHEC reference strains and non-E. coli bacterial species. The detection limit was determined as five tccP or tccP2 copies per reaction. The assay was then evaluated on a large collection of 526 E. coli strains of human, animal, food and environmental origins. The results showed that tccP was restricted to a limited number of serotypes (i.e. O5:H(-) , O55:H7, O125:H6 and O157:H7). The tccP2 gene was present in a higher number of serotypes including the five most frequent EHEC serotypes (i.e. O26:H11, O103:H2, O111:H8, O145:H28 and O157:H7), and a few other serotypes that caused human infections (i.e. O4:H(-) , O45:H2 and O55:H7). A minority of O26:H11 and O103:H2 strains however tested negative for tccP2, though it is not known whether the lack of tccP2 affected their pathogenic potential. Real-time PCR analysis of 400 raw milk cheeses revealed the presence of tccP and/or tccP2 genes in 19·75% of the cheese enrichment suspensions. CONCLUSIONS: A highly specific and sensitive duplex real-time PCR method was developed for rapid and simultaneous detection of tccP and tccP2. Unpasteurized dairy products may be contaminated with E. coli strains carrying tccP and/or tccP2. SIGNIFICANCE AND IMPACT OF THE STUDY: The developed real-time PCR assay represents a valuable alternative to conventional PCR tests and should be useful for characterization of the virulome of pathogenic E. coli strains.

Alpha-synuclein accumulates in the brain of scrapie-affected sheep and goats.

Immunohistochemical examination demonstrated widespread granular deposits of alpha-synuclein (alphaSN) in the brains of sheep and goats with natural scrapie, especially in the cornu ammonis and subiculum of the hippocampus; this contrasted with the diffuse and non-granular immunolabelling seen in healthy controls. There was non-regular "co-localization" of PrP(Sc) and alphaSN. The findings resembled those reported in Creutzfeldt-Jakob disease and in experimental prion disease in hamsters and mice. The results suggest that perturbation of alphaSN metabolism plays a role in human and animal prion diseases.

Absence of the effects of 50 Hz magnetic fields on the progression of acute myeloid leukaemia in rats.

PURPOSE: As the most recent epidemiological studies provide no definite conclusions about the effects of 50/60 Hz magnetic fields (MFs) on the incidence of leukaemia in humans, animal models in a well-controlled environment are useful for evaluating the possibility of an association between MFs and leukaemia. The present study was designed to determine whether 50 Hz magnetic fields can alter the progression of leukaemia. MATERIALS AND METHODS: A well-characterized model of transplantable acute myeloid leukaemia in rats was used for the first time. This model is closely related to human acute myeloid leukaemia, the type most frequently reported in epidemiological studies of adults. After leukaemic cell implantation, rats were exposed to a sinusoidal 50 Hz MF of 100 microT for 18 h a day, 7 days a week, throughout leukaemia progression. The parameters investigated were: survival time, body weight, haematologic parameters, infiltration of blood, bone marrow, spleen and liver by leukaemic cells. RESULTS: The results showed no significant changes (p > 0.05) in leukaemic MF-exposed versus unexposed rats for any of the parameters involved in leukaemia progression. CONCLUSION: These data do not support the hypothesis that 50 Hz magnetic fields influence leukaemia progression in humans.

Can 50 Hz magnetic fields alter iron metabolism and induce anaemia?

UNLABELLED: PURPOSE. Some changes in tissue iron concentration have been reported in animals exposed to electromagnetic fields. In other studies, variations in the haemoglobin level were occasionally observed. In the present experiment, the effects of exposing a rat to a 50 Hz magnetic field (MF) were therefore investigated for the possible induction of anaemia due to changes in iron metabolism. MATERIALS AND METHODS: Male Brown Norway rats (n=225) were exposed to a sinusoidal 50 Hz MF of 500 microT for 15 weeks. Haematological parameters, differential bone marrow cell counts and sideroblasts were investigated. Blood parameters of iron metabolism were measured. Iron concentration and total iron content were also determined in the spleen and liver, to assess iron storage in these organs. RESULTS: Significant differences between the exposed and control rat were only detected for iron storage in the spleen, and for the percentage of bone marrow cells of the red cell lineage. CONCLUSION: The changes observed were not associated with anaemia during the 15 weeks of MF exposure. However, the decrease in bone marrow cells of the red cell lineage and the changes in iron storage detected at the end of the experiment did not allow the possibility to be ruled out that exposure to 50 Hz MFs may induced delayed biological effects.

Urodynamic parameters in scrapie-affected ewes and their modifications in the course of the disease.

The aim of this study was to determine the urological abnormalities linked to spontaneous spongiform encephalopathy and their occurrence in the course of the disease. The animals used in this were 11 healthy and 20 scrapie-affected ewes. The scrapie-affected ewes were studied at a rate of once a month (1 to 5 measures; mean, 2.55) until they died. Urodynamic explorations were performed. The bladder activity was explored using cystometry. The urethral activity was measured during cystometry and during a urethral pressure profile. Both were analyzed using International Continence Society recommendations. Results showed in scrapie-affected ewes a decrease in functional bladder capacity and an increase in detrusor contraction incidence during filling of the bladder and in the occurrence of significant urethral instability. Bladder abnormalities were seen only in scrapie-affected ewes and worsened during the course of the disease. Urethral instability was not typical of the disease but was significantly more frequent in scrapie-affected ewes. It was concluded that lower urinary tract dysfunction occurred in scrapie-affected ewes and worsened during the course of the disease. This dysfunction is in agreement with overactive detrusor function due to neurological lesions.

[Transmissible animal spongiform encephalopathies]. / Les encéphalopathies spongiformes transmissibles animales.

Scrapie in sheep and goats was the first animal spongiform encephalopathy diagnosed. It has since been described in a large number of species (cattle, wild and exotic ruminants, mink, cat). They form an original group of diseases because they are transmissible by a specific pathogen and they depend on the genetic predisposition of the recipient animal. Transmission between species and the possibility of oral transmission underline the need to assess the risk to Man.

[Transmissible animal spongiform encephalopathies. Epidemiologic aspects]. / Les encéphalopathies spongiformes transmissibles animales. Aspects épidémiologiques.

This article presents an update of data about the transmissible spongiform encephalopathies which affect some animal species, particularly bovine spongiform encephalopathy in Great britain and in other countries where this disease is sporadic. The genetic susceptibility of scrapie in sheep and the natural transmission of these spongiform encephalopathies are discussed. The control measures for public health and animal health are presented.

Changes in disposition kinetics of sulphadimidine in response to acute regional liver damage in sheep.

Disposition kinetics of sulphadimidine in sheep, before and after regional liver damage by allyl alcohol, was investigated following a single IV injection (100 mg/kg). Allyl alcohol (12 mg/kg) provoked periportal liver lesion in 60 per cent of the animals. In normal sheep the mean elimination half-life of sulphadimidine was 7.47 +/- 1.09 hours. Liver damage significantly increased this value to 11.68 +/- 1.09 hours. Liver damage by allyl alcohol significantly changed the total body clearance (C1B), the overall elimination rate constant (beta) and the micro-constants k12 and kCl. The apparent volume of distribution (Vd) and the micro-constant k21 were not influenced by liver damage. The mean minimum steady-state concentration (Cp[min]) in normal sheep (38.43 micrograms/ml at 24 hours of interval) was found to be higher than previously reported. Liver intoxication significantly increased this value to 94.38 micrograms/ml. It is suggested that the regional liver damage has affected both the elimination and biotransformation of sulphadimidine.

[Effect of vasopressin on the motor profile of the reticulum and rumen in sheep]. / Effets de la vasopressine sur le profil moteur du réticulo-rumen chez le mouton.

Intravenous injections of lysine-vasopressin into sheep inhibited rumino-reticular phasic contractions and electric activity. Sometimes, a rapid electric pattern was observed and persisted even after reappearance of normal phasic contractions.

Stimulated esophageal groove closure in adult goats.

In healthy adult goats, closure of the esophageal groove was induced by thirst, IV administered vasopressin, and intracarotid administration of hypertonic NaCl solutions. The efficiency of stimulation was tested directly by visual inspection of the course taken by orally administered solutions through a ruminal or abomasal fistula, palpation of the lips of the esophageal groove through a ruminal fistula, and indirectly by following the glucose dynamics in the blood after oral administration of glucose solution. Esophageal groove closure was observed during drinking after a 48-hour period of water deprivation. Intracarotid administration of 1.5 ml of a saturated solution or 10.5 ml of a 1.5% solution of NaCl also stimulated groove closure; however, groove closure stimulated by administration of vasopressin is the most satisfactory procedure for passing compounds of therapeutic importance directly from the cardiac orifice to the abomasum.

[Modification of food and water intake after experimental duodenal occlusion in the sheep]. / Modification de l'ingestion et de l'abreuvement après occlusion duodénale expérimentale chez le mouton.

A duodenal occlusion was performed near the pylorus in 10 sheep fed hay ad libitum and barley (350 g/day). The first day, grain intake ceased and a 60% decrease in forage and water intake occurred. Hay intake approached zero on day 4, but some water intake persisted, probably because of the continuation of diuresis.

[Establishment of a re-entrant ileo-cecal fistula in Equidae]. / Mise au point d'une fistule iléo-caecale ré-entrante chez les équidés.

A re-entrant cannulation of the digestive tract was performed in Equidae (ponies and donkeys) between the distal extremity of the ileum and the base of the caecum. The operative technique was conceived to avoid risks of infection of the peritoneal cavity: the openings of the ileum and of the caecum were achieved only after the closure of the abdominal wall incision. Two donkeys were still alive ten months after the operation. This method can provide a convenient model for digestibility studies in Equidae, particularly for assessment of the pre-caecal digestibility.

Titrimetry as a method of assessment of rumen contents.

Titration of rumen fluid reveals the prevailing buffer system: VFA salts and sometimes bicarbonates in the normal state, ammonium salts or lactate in pathological conditions. Titrimetry appears to be a convenient method to study digestion in the rumen.