Maintenance and breeding of Thrichomys (Trouessart, 1880) (Rodentia: Echimyidae) in captivity

South American histricognath rodents Thrichomys apereoides laurentius and Thrichomys pachyurus are natural hosts of Trypanosoma cruzi, agent of Chagas disease. We established breeding colonies of these species to serve as experimental models in various parasitological studies. Both species of Thrichomys have all the requirements necessary to become excellent laboratory models: they can be easily maintained in the standard laboratory conditions and breed throughout the year and they do not have any special dietary demands and can be fed by standard food pellets designed for laboratory mice. Both species produce precocious offspring that have their eyes and ears open, teeth erupted, fur well developed, and can eat solid food in the first week of life. T. a. laurentius has larger litter sizes and lower body masses at birth and weaning than T. pachyurus. Moreover, females of T. a. laurentius reach puberty earlier and with lower body mass than T. pachyurus

Lower Richness of Small Wild Mammal Species and Chagas Disease Risk

A new epidemiological scenario involving the oral transmission of Chagas disease, mainly in the Amazon basin, requires innovative control measures. Geospatial analyses of the Trypanosoma cruzi transmission cycle in the wild mammals have been scarce. We applied interpolation and map algebra methods to evaluate mammalian fauna variables related to small wild mammals and the T. cruzi infection pattern in dogs to identify hotspot areas of transmission. We also evaluated the use of dogs as sentinels of epidemiological risk of Chagas disease. Dogs (n = 649) were examined by two parasitological and three distinct serological assays. kDNA amplification was performed in patent infections, although the infection was mainly sub-patent in dogs. The distribution of T. cruzi infection in dogs was not homogeneous, ranging from 11–89% in different localities. The interpolation method and map algebra were employed to test the associations between the lower richness in mammal species and the risk of exposure of dogs to T. cruzi infection. Geospatial analysis indicated that the reduction of the mammal fauna (richness and abundance) was associated with higher parasitemia in small wild mammals and higher exposure of dogs to infection. A Generalized Linear Model (GLM) demonstrated that species richness and positive hemocultures in wild mammals were associated with T. cruzi infection in dogs. Domestic canine infection rates differed significantly between areas with and without Chagas disease outbreaks (Chi-squared test). Geospatial analysis by interpolation and map algebra methods proved to be a powerful tool in the evaluation of areas of T. cruzi transmission. Dog infection was shown to not only be an efficient indicator of reduction of wild mammalian fauna richness but to also act as a signal for the presence of small wild mammals with high parasitemia. The lower richness of small mammal species is discussed as a risk factor for the re-emergence of Chagas disease

Spinal motoneuron synaptic plasticity during the course of an animal model of multiple sclerosis

During the course of experimental autoimmune encephalomyelitis, a massive loss of motor and sensitive function occurs, which has been classically attributed to the demyelination process. In rats, the clinical signs disappear within 5 days following complete tetraplegia, indicating that demyelination might not be the only cause for the rapid evolution of the disease. The present work investigated the occurrence of experimental autoimmune encephalomyelitis-induced changes of the synaptic covering of spinal motoneurons during exacerbation and after remission. The terminals were typed with transmission electron microscopy as C-, F- and S-type. Immunohistochemical analysis of synaptophysin, glial fibrillary acidic protein and the microglia/macrophage marker F4/80 were also used in order to draw a correlation between the synaptic changes and the glial reaction. The ultrastructural analysis showed that, during exacerbation, there was a strong retraction of both F- and S-type terminals. In this sense, both the covering as well as the length of the remaining terminals suffered great reductions. However, the retracted terminals rapidly returned to apposition, although the mean length remained shorter. A certain level of sprouting may have occurred as, after remission, the number of F-terminals was greater than in the control group. The immunohistochemical analysis showed that the peak of synaptic loss was coincident with an increased macro- and microglial reaction. Our results suggest that the major changes occurring in the spinal cord network during the time course of the disease may contribute significantly to the origin of the clinical signs as well as help to explain their rapid recovery.24113053306

Evaluation of a New Surgical Light Source for Difficult Visibility Procedures

A new lighting device for open surgery of difficult access wounds was designed: the Extender add-on. The performance of the Extender is evaluated and compared with the conventional solutions used in the operating room (OR) on illumination quality. A cylindrical setup was built to measure the distribution of light in a simulated pelvic wound. The light was provided by a head-mounted light, an OR light, and a pair of Extender prototypes. The results showed that the Extender prototypes provided 12.2 lumens inside the wound, whereas the head-mounted light gave 5.7 lumens. The Extenders provided smoothly angular distributed light from 0 degrees to 180 degrees, whereas the head-mounted light and OR light only provided light from 115 degrees to 180 degrees. The Extender prototypes had a promising performance in terms of light distribution. It is expected that a more accurately produced Extender will increase performance in terms of illumination quantity and illumination distribution smoothness even further

Major Histocompatability Complex Class I Expression and Glial Reaction Influence Spinal Motoneuron Synaptic Plasticity During the Course of Experimental Autoimmune Encephalomyelitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Recent studies have shown that major histocompatibility complex class I (MHC I) expression directly influences the stability of nerve terminals. Also, the acute phase of experimental autoimmune encephalomyelitis (EAE) has shown a significant impact on inputs within the spinal cord. Therefore, the present work investigated the synaptic covering of motoneurons during the induction phase of disease and progressive remissions of EAE. EAE was induced in C57BL/6J mice, which were divided into four groups: normal, peak disease, first remission, and second remission. The animals were killed and their lumbar spinal cords processed for in situ hybridization (IH), immunohistochemistry, and transmission electron microscopy (TEM). The results indicated an increase in glial reaction during the peak disease. During this period, the TEM analysis showed a reduction in the synaptic covering of the motoneurons, corresponding to a reduction in synaptophysin immunolabeling and an increase in the MHC I expression. The IH analysis reinforced the immunolabeling results, revealing an increased expression of MHC I mRNA by motoneurons and nonneuronal cells during the peak disease and first remission. The results observed in both remission groups indicated a return of the terminals to make contact with the motoneuron surface. The ratio between excitatory and inhibitory inputs increased, indicating the potential for development of an excitotoxic process. In conclusion, the results presented here indicate that MHC I up-regulation during the course of EAE correlates with the periods of synaptic plasticity induced by the infiltration of autoreactive immune cells and that synaptic plasticity decreases after recurrent peaks of inflammation. J. Comp. Neurol. 518:990-1007, 2010. (C) 2009 Wiley-Liss, Inc.51879901007Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2006/05055-4, 2007/03645-1, 2009/16879-6]CNPq [304834/2006-8

Differential Schwann cell migration in adult and old mice: an in vitro study

The influence of aging on Schwann cell (SC) proliferation, migration and viability was studied in vitro. SCs were cultured in Ham F-10 medium enriched with 20% fetal calf serum (FCS), 40% FCS or collagen I gel plus 20% FCS. The migration of adult mice derived SCs was stimulated with FCS and collagen. With aging, SC migration, multiplication and viability decreased, indicating that ideal culturing conditions should be adjusted. (C) 2000 Elsevier Science B.V. All rights reserved.8811737