Bilateral hibernomas in the femoral regions of a dog.

A 14-year-old intact male Chihuahua dog was presented with masses located between the biceps femoris and adductor muscles in both hind limbs. Based on histopathological, immunohistochemical, and ultrastructural findings, we diagnosed these masses as bilateral hibernomas in the femoral regions. The dog had no evidence of recurrence or metastasis of the hibernomas through a 4-month postoperative follow-up. This is apparently the first report of bilateral hibernomas in the femoral regions of a dog. Key clinical message: Bilateral hibernomas should be considered as a differential diagnosis for masses occurring in the femoral regions of dogs.

Hibernomes bilatéraux dans les régions fémorales d'un chien. Un chien Chihuahua mâle intact de 14 ans a été présenté avec des masses situées entre le biceps fémoral et les muscles adducteurs des deux membres postérieurs. Sur la base des résultats histopathologiques, immunohistochimiques et ultrastructuraux, nous avons diagnostiqué ces masses comme des hibernomes bilatéraux dans les régions fémorales. Le chien n'avait aucun signe de récidive ou de métastases des hibernomes au cours d'un suivi postopératoire de 4 mois. Il s'agit apparemment du premier rapport d'hibernome bilatéral dans les régions fémorales d'un chien.Message clinique clé:Les hibernomes bilatéraux doivent être considérés comme un diagnostic différentiel pour les masses survenant dans les régions fémorales des chiens.(Traduit par Dr Serge Messier).

In vivo characterization of a Toxoplasma gondii strain TgCatJpTy1/k-3 isolated from a stray cat in Japan.

The Toxoplasma gondii strain TgCatJpTy1/k-3 (K-3), isolated from a stray cat in Tokyo, Japan, is categorized as a type II genotype. Since the K-3 strain is empirically known to form relatively larger cysts and exhibit weak pathogenesis in a mouse, it could serve as a useful model organism to study chronic T. gondii infection in the host. However, a detailed biological characterization of this strain had not been performed. In this study, we thoroughly assessed the K-3 strain in vivo using a mouse model. Tests indicated that pathogenicity of the K-3 strain was lower than that of the PLK strain, a clonal laboratory strain with a moderately pathogenic type II genotype. Further, cyst sizes of the K-3 strain were significantly larger than those of the PLK strain. Interestingly, K-3 cyst sizes in T. gondii-resistant ICR mice were larger than those in T. gondii-susceptible C57BL/6N mice. Our study suggests that the K-3 strain is suitable to study T. gondii cystogenesis and chronic infection, which are currently difficult to analyze using cell-adopted T. gondii strains.

Susceptibility to Various Coccidiostats in the Murine Coccidian Parasite Eimeria krijgsmanni.

INTRODUCTION: Murine Eimeria spp. have been used as effective experimental models of disease instead of large mammalian hosts such as cattle. We here examine drug susceptibility of the uncharacterized murine intestinal protozoan parasite, Eimeria krijgsmanni. MATERIALS AND METHODS: The effectiveness of different treatments against infection of E. krijgsmanni was examined for suppression of oocyst shedding: ST mixture ST mixture, pyrimethamine, Ektecin and toltrazuril. RESULTS: ST mixture and pyrimethamine did not suppress oocyst shedding effectively. Although therapeutic efficacy of Ektecin was demonstrated, the dose required was larger than that for cattle and chickens. Oocyst shedding was only completely suppressed completely by continuous administration of toltrazuril. Furthermore, it was confirmed through morphological examination that early developmental stage zoites appeared in host epithelial cells during and following treatment by toltrazuril, and toltrazuril could not eliminate residual zoites in epithelial cells. CONCLUSION: E. krijgsmanni may be relatively resistant to these anti-coccidian agents and might therefore have different characteristics that differ from other coccidia with regard to drug susceptibility.

Evaluation of vaccine potential of 2-Cys peroxiredoxin from the hard tick Haemaphysalis longicornis.

Ticks require blood feeding on vertebrate animals throughout their life cycle, and also concentrate the iron-containing blood, resulting in a high concentration of hydrogen peroxide (H2O2). High concentrations of H2O2 are harmful to organisms, due to their serious damage of macromolecules. Ticks have antioxidant enzymes, such as peroxiredoxins (Prxs), that scavenge H2O2. Prxs may have important roles in regulating the H2O2 concentration in ticks during blood feeding and oviposition. Moreover, Prxs are considered potential vaccine candidates in other parasites, such as Leishmania and Fasciola. In the present study, the efficacy of a tick Prx (HlPrx2) as a vaccine candidate antigen was evaluated. First, recombinant HlPrx2 (rHlPrx2) was expressed in Escherichia coli, and then, its purity and endotoxin levels were confirmed prior to administration. The rHlPrx2 proteins were of high purity with acceptably low endotoxin levels. Second, the ability of rHlPrx2 administration to stimulate mouse immunity was evaluated. The rHlPrx2 protein, with or without an adjuvant, could stimulate immunity in mice, especially the IgG1 of Th2 immune response. Using Western blot analysis, we also observed whether rHlPrx2-immunized mice sera could recognize native HlPrx2 protein in crude tick midgut proteins. Western blot analysis demonstrated that rHlPrx2-administrated mouse sera could detect the native HlPrx2. Finally, the effects of rHlPrx2 immunization in mice were studied using nymphal ticks. Although the challenged ticks were not affected by rHlPrx2 immunization, rHlPrx2 still might be considered as a vaccine candidate against ticks because of its high immunogenicity.

Comb Atrophy after Bile Duct Ligation in Chickens.

Gross, histological, and immunohistochemical changes in the combs of chickens after bile duct ligation (BDL) are described. Gross reductions in comb size and volume and lower serum testosterone levels were evident in chickens after BDL. Histologically, atrophic combs were characterized by reduced blood capillary diameter, decreased acid mucopolysaccharides, thinning of the stratum germinativum of the epidermis and dermis, and reduced immunostaining intensity of androgen receptors. These results suggest that the affected cells in atrophic combs are androgen targets. BDL caused testicular atrophy in chickens, a primary complication of liver disease, and the resultant low serum testosterone levels subsequently caused atrophy of the comb. In other words, the atrophy of the comb observed in BDL chickens was a secondary complication of liver dysfunction that simulated the effects of liver disease.

Course of induced infection by Eimeria krijgsmannni in immunocompetent and immunodeficient mice.

Recently, we have demonstrated the utility of Eimeria krijgsmanni as a novel mouse eimerian parasite for elucidating the biological diversity. The parasite showed notable infectivity to mice with various levels of immune status and susceptibility to antimicrobial agents including coccidiostat. However, the detailed lifecycle of E. krijgsmanni had not yet been determined and this information was lacking in discussion of previous findings. In the present study, we clarified the morphological characteristics of E. krijgsmanni and its lifecycle in normal mice, and examined the effects in immunodeficient mice and lifecycle stage for challenge infections after the primary inoculation. In immunocompetent mice, the lifecycle consisted of four asexual stages and the sexual sages followed by formation of oocysts during the prepatent periods. Interestingly, the second-generation meronts were detected in all observation periods after the disappearance of the other stages. For the challenge infection of immunodeficient mice, all developmental stages except for the second generation meronts were temporarily vanished. This finding suggests a "rest" or marked delay in development and a "restart" of the promotion toward the next generations. The second generation meronts may play an important role in the lifecycle of E. krijgsmanni.

Evaluation of Eimeria krijgsmanni as a murine model for testing the efficacy of anti-parasitic agents.

Murine Eimeria spp. have been used as effective models of disease instead of large mammalian hosts such as cattle. We attempted to establish in vivo and in vitro assays using a murine intestinal protozoan, Eimeria krijgsmanni, which we previously isolated, to test anti-parasitic agents. Consequently, when mice were treated with sulfur drugs or toltrazuril, which are commercially available for livestock. Furthermore, sporulated oocysts and excysted sporozoites of E. krijgsmanni were treated with naturally occurring substances (lactoferrin, longicin, and curcumin). Although exposure to these substances did not affect oocyst infectivity, sporozoite viability decreased by 60% with longicin. However, direct injection of sporozoites treated with longicin into mice ceca did not result in any changes in the oocyst shedding pattern compared with control mice. The results suggest that E. krijgsmanni could be resistant to these anti-parasitic agents and might therefore have different characteristics to other apicomplexan parasites.

Age-related histological changes in kidneys of Brown Norway rat.

In this study, age-dependent histological changes in the kidneys of Brown Norway rat, a strain useful for conducting aging research, were evaluated. Examination was performed at 3, 12, 18, 24 and 30 months of age. Sclerotic and hypertrophic changes of the glomeruli were observed, and quantitative scores of these changes persistently increased with age. A marginal increase in scores was observed for glomerular cystic changes and tubulointerstitial damage. Further, urothelial hyperplasia was observed in the renal papillae, particularly at 30 months of age. In conclusion, the findings of the present study demonstrate that the Brown Norway strain exhibits persistent, but mild progression of age-dependent renal histological changes.

Bone mineral analysis through dual energy X-ray absorptiometry in laboratory animals.

To determine how to eliminate species difference in animal bone experiment, bone mineral content (BMC) was measured using dual energy X-ray absorptiometry (DXA) on the femurs of laboratory mice (Mus musculus) and rats (Rattus norvegicus), and common marmosets (Callithrix jacchus). Measures were taken on femurs in situ, detached from the body, skinned and defleshed, or dried completely. When the BMC of the bone measured in the intact limb attached to the trunk was set at 100%, the actual BMC of the dry bone was 58.7 +/- 11.5% in mice and 103.2 +/- 3.2% in rats. Similarly, the bone area (Area) and bone mineral density (BMD) of the dried femur was significantly lower in the mouse femurs than intact limb. Thus, soft limb tissue such as skin and muscle modified the BMC, Area, and BMD only in mouse but not in those from rats or marmosets. The bone mineral ratio (BMR; BMC divided by dry bone weight) was nearest to the human bone value in the rat femurs, whereas the mouse femur BMR was the most different. The BMR was proved to be a practical index in evaluating bone characteristics in laboratory animals, but the mouse femur might not be suitable as an animal model for research into the aging of human bone.

Body and major organ weights of A/J-Chr 11(SM) consomic mice.

The body and major organ weights of A/J-Chr 11(SM) consomic mice were compared to those of the progenitor strains, A/J and SM/J. The weights of the body and organs, except for those of the brain and uterus, were significantly greater in A/J mice than in SM/J mice. However, those of consomic mice were highly variable. For example, the average body weight of consomic mice was significantly greater than that of SM/J mice and nearly equal to that of A/J mice. Chromosome 11 of SM/J mice induced various significant changes of the organ weights of A/J mice, especially those of the brain, lung, kidney, adrenal, and ovary, demonstrating the importance of this chromosome in determining the phenotypes.

A morphometric study of the adrenal cortex of the female DDD mouse.

The aim of this study was to determine whether the thickness of the adrenocortical zone is associated with age in virgin and parous female DDD mice. The zona reticularis and zona glomerulosa of parous mice tended to be thicker than those of virgin mice at all ages. The zona fasciculata lactating parous mice was significantly thicker than that of virgin mice at 20 weeks of age (P<0.01). Age did not affect the thickness of the three outer adrenocortical zones in either group. However, in virgin mice, the X zone consisted of vacuolated and nonvacuolated cells at 5 weeks of age and only of vacuolated cells at 10 weeks of age; the number of vacuolated cells and the thickness of the zone decreased at 40 weeks of age. In contrast, parous mice of all ages lacked an X zone. The decrease in X zone thickness with age was most evident when expressed relative to organ weight. In conclusion, the thickness of the outer three adrenocortical zones is affected by endocrine changes associated with pregnancy and lactation but not by age. The thickness of the X zone is an index of growth and maturation in nulliparous female DDD mice less than one year of age.