Morphometric Analysis of Enteric Lesions in C3H/HeN Mice Inoculated with \u3ci\u3eSerpulina hyodysenteriae\u3c/i\u3e Serotypes 2 and 4 with or without Oral Streptomycin Pretreatment

The segmental distribution and sequential progression and the role of the indigenous bacterial flora in the development of enteric lesions associated with Serpulina hyodysenteriae infection in laboratory mice have not been defined. We examined the distribution and sequential morphometric changes in the large intestine of mice orally inoculated with S. hyodysenteriae serotypes 2 and 4. To determine the role of colonization resistance conferred by the indigenous bacterial flora, 40 female C3H/HeN mice were administered water alone or water containing 5 mg/mL streptomycin sulfate ad libitum for seven days prior to orogastric inoculation either with S. hyodysenteriae or sterile trypticase soy broth (TSB). Clinical signs were monitored daily and three mice per group were necropsied on postinoculation days (PID) 7 and 14 for pathological assessment of the cecum, proximal colon, transverse colon, and descending colon, and bacteriological culture of the cecum for S. hyodysenteriae. Weekly pooled fecal samples were collected from each group for determination of total numbers of anaerobe bacteria. Gross examination revealed soft fecal pellets on PID 7 and 14 and catarrhal typhlitis on PID 14, irrespective of streptomycin pretreatment. The recovery rates of S. hyodysenteriae from the ceca of serotype 2- and serotype 4-inoculated mice was 100 and 91.7%, respectively. Statistically significant differences in morphometric changes between TSB- and S. hyodysenteriae- inoculated mice were present on PID 7 and 14 and were restricted to the cecum. Although oral administration of streptomycin for seven days prior to S. hyodysenteriae inoculation resulted in a significant reduction in the numbers of fecal anaerobes, it did not affect the colonization, distribution, severity, or progression of cecal lesions. La distribution segmentaire, la progression sequentielle et le role de la flore bacterienne indigene dans le developpement des lesions enteriques associees \u27a une infection par Serpulina hyodysenteriae chez des souris de laboratoire ne sont toujours pas connus. Nous avons etudie la distribution et les changements morphometriques sequentiels du gros intestin de souris inoculees oralement avec S. hyodysenteriae serotypes 2 et 4. Afin d\u27evaluer le role de la flore bacterienne indigene dans la resistance a la colonisation, 40 souris femelles C3H/HeN ont requ de l\u27eau uniquement ou de l\u27eau contenant 5 mg/mL de streptomycine ad libidum pendant sept jours avant d\u27etre inoculees par voie orogastrique avec S. hyodysenteriae ou un bouillon sterile. Les signes cliniques ont ete notes a chaque jour et trois souris de chacun des groupes ont ete necropsiees aux jours 7 et 14 post-inoculation (PI) pour examen du caecum, du colon proximal, du c\u27lon transverse et du colon descendant et pour culture bacterienne du caecum. Des pools de feces ont ete obtenus a chaque semaine pour determiner le nombre total de bacteries anaerobies. L\u27examen macroscopique a revele la presence de feces molles aux jours 7 et 14 PI et d\u27une typhlite catarrhale au jour 14 PI, que les animaux aient requ ou non de la streptomycine. S. hyodysenteriae serotype 2 et serotype 4 a etet reisole\u27 respectivement de 100 et 91,7 % des caeca des souris inoculees. Des differences statistiquement significatives de changements morphometriques ont ete observees aux jours 7 et 14 PI entre les souris inoculees avec un bouillon sterile et celles ayant recu S. hyodysenteriae et ce, uniquement dans le caecum. Bien que l\u27administration orale de streptomycine ait reduit de facon significative le nombre d\u27anaerobes fecaux, elle n\u27a pas affecte la colonisation, la distribution, la severite ou la progression des lesions. (Traduit par Dre Christiane Girard

Morphometric Analysis of Enteric Lesions in C3H/HeN Mice Inoculated with \u3ci\u3eSerpulina hyodysenteriae\u3c/i\u3e Serotypes 2 and 4 with or without Oral Streptomycin Pretreatment

The segmental distribution and sequential progression and the role of the indigenous bacterial flora in the development of enteric lesions associated with Serpulina hyodysenteriae infection in laboratory mice have not been defined. We examined the distribution and sequential morphometric changes in the large intestine of mice orally inoculated with S. hyodysenteriae serotypes 2 and 4. To determine the role of colonization resistance conferred by the indigenous bacterial flora, 40 female C3H/HeN mice were administered water alone or water containing 5 mg/mL streptomycin sulfate ad libitum for seven days prior to orogastric inoculation either with S. hyodysenteriae or sterile trypticase soy broth (TSB). Clinical signs were monitored daily and three mice per group were necropsied on postinoculation days (PID) 7 and 14 for pathological assessment of the cecum, proximal colon, transverse colon, and descending colon, and bacteriological culture of the cecum for S. hyodysenteriae. Weekly pooled fecal samples were collected from each group for determination of total numbers of anaerobe bacteria. Gross examination revealed soft fecal pellets on PID 7 and 14 and catarrhal typhlitis on PID 14, irrespective of streptomycin pretreatment. The recovery rates of S. hyodysenteriae from the ceca of serotype 2- and serotype 4-inoculated mice was 100 and 91.7%, respectively. Statistically significant differences in morphometric changes between TSB- and S. hyodysenteriae- inoculated mice were present on PID 7 and 14 and were restricted to the cecum. Although oral administration of streptomycin for seven days prior to S. hyodysenteriae inoculation resulted in a significant reduction in the numbers of fecal anaerobes, it did not affect the colonization, distribution, severity, or progression of cecal lesions. La distribution segmentaire, la progression sequentielle et le role de la flore bacterienne indigene dans le developpement des lesions enteriques associees \u27a une infection par Serpulina hyodysenteriae chez des souris de laboratoire ne sont toujours pas connus. Nous avons etudie la distribution et les changements morphometriques sequentiels du gros intestin de souris inoculees oralement avec S. hyodysenteriae serotypes 2 et 4. Afin d\u27evaluer le role de la flore bacterienne indigene dans la resistance a la colonisation, 40 souris femelles C3H/HeN ont requ de l\u27eau uniquement ou de l\u27eau contenant 5 mg/mL de streptomycine ad libidum pendant sept jours avant d\u27etre inoculees par voie orogastrique avec S. hyodysenteriae ou un bouillon sterile. Les signes cliniques ont ete notes a chaque jour et trois souris de chacun des groupes ont ete necropsiees aux jours 7 et 14 post-inoculation (PI) pour examen du caecum, du colon proximal, du c\u27lon transverse et du colon descendant et pour culture bacterienne du caecum. Des pools de feces ont ete obtenus a chaque semaine pour determiner le nombre total de bacteries anaerobies. L\u27examen macroscopique a revele la presence de feces molles aux jours 7 et 14 PI et d\u27une typhlite catarrhale au jour 14 PI, que les animaux aient requ ou non de la streptomycine. S. hyodysenteriae serotype 2 et serotype 4 a etet reisole\u27 respectivement de 100 et 91,7 % des caeca des souris inoculees. Des differences statistiquement significatives de changements morphometriques ont ete observees aux jours 7 et 14 PI entre les souris inoculees avec un bouillon sterile et celles ayant recu S. hyodysenteriae et ce, uniquement dans le caecum. Bien que l\u27administration orale de streptomycine ait reduit de facon significative le nombre d\u27anaerobes fecaux, elle n\u27a pas affecte la colonisation, la distribution, la severite ou la progression des lesions. (Traduit par Dre Christiane Girard

Molecular understanding of aluminum-induced topological changes in (CCG)<SUB>12</SUB> triplet repeats: relevance to neurological disorders

Recent studies have shown that gene mutations are involved in the pathology of neurological disorders. CCG repeats cause genetic instability and are localized at the 5′ end of the non-coding regions of the FMR1 gene in fragile X syndrome. Our studies for the first time showed that aluminum (Al) levels were elevated in the serum samples of fragile X syndrome and also provide evidence for the interaction of aluminum with (CCG)<SUB>12</SUB>-repeats. Circular dichroism spectroscopic studies of (CCG)<SUB>12</SUB> indicated B-DNA conformation and in the presence of Al (10<SUP>-5</SUP> M) CCG repeats attained Z-DNA conformation. Further spectroscopic studies, which included melting profiles, ethidium bromide binding patterns and interaction of Z-DNA specific polyclonal antibodies confirmed the Z-conformation in (CCG)<SUB>12</SUB>-repeats in the presence of Al (10<SUP>-5</SUP> M). It is interesting to mention that Al-induced Z-conformation is stable even after the total removal of Al from CCG by desferoximine, a chelating drug. This is the first report to proof the role of Al in modulating the DNA (CCG repeats) topology and this information provides a clue about the possible involvement of Al at a molecular level in neurological/neurodegenerative disorders

Helicobacter hepaticus Hydrogenase Mutants Are Deficient in Hydrogen-Supported Amino Acid Uptake and in Causing Liver Lesions in A/J Mice

Helicobacter hepaticus, a causative agent of chronic hepatitis and hepatocellular carcinoma in mice, expresses a nickel-containing hydrogen-oxidizing hydrogenase enzyme. Growth of a hyaB gene-targeted mutant was unaffected by the presence of hydrogen, unlike the wild-type strain, which showed an enhanced growth rate when supplied with H(2). Hydrogenase activities in H. hepaticus were constitutive and not dependent on the inclusion of H(2) during growth. Addition of nickel during growth significantly stimulated both urease (for wild-type and hyaB) and hydrogenase (for wild-type) activities. In a 5-h period, the extent of (14)C-labeled amino acid uptake by the wild type was markedly enhanced in the presence of hydrogen and was >5-fold greater than that of the hyaB mutant strain. In the presence of H(2), the short-term whole-cell amino acid uptake V(max) of the parent strain was about 2.2-fold greater than for the mutant, but the half-saturation affinity for amino acid transport was the same for the parent and mutant strain. The liver- and cecum-colonizing abilities of the strains was estimated by real-time PCR quantitation of the H. hepaticus-specific cytolethal distending toxin gene and showed similar animal colonization for the hyaB mutant and the wild type. However, at 21 weeks postinoculation, the livers from mice inoculated with wild type exhibited moderate lobular lymphoplasmacytic hepatitis with hepatocytic coagulative necrosis, but the hydrogenase mutants exhibited no histological evidence of lobular inflammation or necrosis

Toxicologic Pathology Forum: Opinion on Obligatory Microscopic Examination of Intermediate-Dose Groups in Toxicity Studies With Biotherapeutics in Cynomolgus Monkeys

In nonrodent toxicity studies that are usually conducted in cynomolgus monkeys or beagle dogs, the added value of examining all tissues from all dose groups (current practice) versus all tissues in only control and high-dose groups and target tissues in intermediate-dose groups by default, is a subject of debate. A previous retrospective review of 325 nonrodent toxicity studies that included a limited number of biotherapeutics suggested that the evaluation of all tissues from all groups was not justified as a routine practice and recommended the examination of all tissues in control and high-dose groups and only target tissues in intermediate-dose groups. In contrast, the present retrospective review which examined 213 nonrodent studies (212 in cynomolgus monkeys and 1 in dog) from 4 multinational pharmaceutical companies (Bristol-Myers Squibb, Novartis, Pfizer Inc, and Roche) conducted only with biotherapeutics showed that restricting the microscopic examination in intermediate-dose groups to target tissues has the potential to miss findings in 6.6% of studies, possibly impacting the overall study interpretation and conclusion. In conclusion and in the opinion of the authors, all tissues from all dose groups should be examined in toxicity studies with biotherapeutics conducted in nonrodent species

Hoof size, shape, and balance as possible risk factors for catastrophic musculoskeletal injury of Thoroughbred racehorses

abstract: 95 Thoroughbred racehorses that died between 1994 and 1996 examined through the California Horse Racing Board Postmortem Program were used in this investigation. 38 quantitative measures of hoof size, shape and balance were obtained from orthogonal digital images of the hoof and were compared between case horses with forelimb catastrophic musculoskeletal injuries (CMI, 70 animals), suspensory apparatus failure (SAF, 43), and cannon bone condylar fracture (CDY, 10) injuries and control horses whose death was unrelated to the musculoskeletal system (non-CMI, 25). Comparison of group means between cases and controls was done using ANOVA and multivariable logistic regression was used to estimate odds ratios. Odds of CMI were 0.62 times lower for a 5-mm increase in ground surface width difference and 0.49 times lower for a 100-mm² increase in sole area difference. Odds of SAF were 6.75 times greater with a 10° increase in toe-heel angle difference and 0.58 times lower with a 100-mm² increase in sole area difference. Odds of CDY were 0.26 times lower with a 3° increase in toe angle, 0.15 times lower with a 5-mm increase in lateral ground surface width, and 0.35 times lower with a 100-mm² increase in sole area difference. It is suggested that decreasing the difference between toe and heel angles should decrease risk of SAF for Thoroughbred racehorses and should be considered in addition to increasing toe angle alone to help prevent catastrophic injury. It is added that trimming the hoof to perfect mediolateral symmetry may not be a sound approach to avoiding injury