Kinetic gait analysis in English Bulldogs

Background

Canine breed conformation may interfere with locomotion and may predispose to orthopedic disease. Bulldogs have a high incidence of orthopedic diseases such as hip dysplasia. Kinetic gait analysis provides an objective way to assess and analyze locomotion. The aim of this study was to study the vertical forces of English Bulldogs during walk using a pressure sensitive walkway. We hypothesize that Bulldogs affected by orthopedic diseases have decreased weight bearing and asymmetric locomotion in the limbs despite having mild to no sings during clinical examination. Thirty English Bulldogs were tested. Peak vertical force, vertical impulse, rate of loading, stance phase duration, symmetry index, goniometry and incidence of orthopedic diseases were recorded.

Results

Although none of the dogs showed signs of pain or discomfort upon manipulation of the hip joints, all dogs had radiographic evidences of hip dysplasia and lack of significant peak vertical force, vertical impulse and stance time differences. The dogs had a mean hind limb symmetry index of 19.8 ± 19.5% and rates of loading ranged from 1.0 to 3.1.

Conclusions

Despite the lack of evident decrease in weight bearing, subclinical lameness can be inferred. The examined dogs had a mean hind limb symmetry index of 19.8 ± 19.5%. Symmetry indices reported in dogs free from orthopedic diseases range from 0.3 to 9.6%. Given non-lame dogs are expected to have a symmetry index close to 0%, data from this study suggests that Bulldogs have gait dysfunctions, which translates into hind limb asymmetries and rate of loading was consistent with severe hip dysplasia despite no visible signs of gait dysfunction. Future studies comparing lame and non-lame Bulldogs are warranted.

     

One-step refolding and purification of disulfide-containing proteins with a C-terminal MESNA thioester

Background  

Expression systems based on self-cleavable intein domains allow the generation of recombinant proteins with a C-terminal thioester. This uniquely reactive C-terminus can be used in native chemical ligation reactions to introduce synthetic groups or to immobilize proteins on surfaces and nanoparticles. Unfortunately, common refolding procedures for recombinant proteins that contain disulfide bonds do not preserve the thioester functionality and therefore novel refolding procedures need to be developed.     

Restricted Feeding Schedules Modulate Free-running Drinking Activity in Malnourished Rats

Low protein malnourished rats held in 12 : 12 light-dark conditions exhibit two bouts of drinking activity, which resemble a “splitting” pattern. These findings have suggested a weak coupling force between the light-(LEO) and the food-entrainable oscillators (FEO). Food restriction to a few hours daily exerts a strong entraining influence on FEO and allows to uncouple both oscillators. To further understand the coupling relation between LEO and FEO, we evaluated the influence of restricted feeding schedules (RFS) on the circadian rhythm of drinking behavior in malnourished rats and their controls. Adult rats were entrained to RFS with a low protein or a regular chow diet in a counterbalanced design. All groups developed drinking anticipatory activity (FAA) to meal time, with similar intensity and onset time. RFS produced lengthening in the period of LEO's free-running rhythm and this effect was significant in MAL rats. Behavioral patterns in control as well as malnourished rats entrained with regular chow indicated independence between LEO and FEO. In contrast, 60% of MAL rats entrained with the low protein diet exhibited phase control by meal time on LEO's free-running. Present data indicate that low protein diets may induce enhanced potency of food as an entraining signal and produce a change in the coupling force between both oscillators, promoting that LEO couples to the FEO. In such conditions FEO seems to override the influence of LEO on the temporal organization of behavior and imposes its phase on the free-running component.     

Antioxidant effects of different extracts from Melissa officinalis, Matricaria recutita and Cymbopogon citratus

Considering the important role of oxidative stress in the pathogenesis of several neurological diseases, and the growing evidence of the presence of compounds with antioxidant properties in the plant extracts, the aim of the present study was to investigate the antioxidant capacity of three plants used in Brazil to treat neurological disorders: Melissa officinalis, Matricaria recutita and Cymbopogon citratus. The antioxidant effect of phenolic compounds commonly found in plant extracts, namely, quercetin, gallic acid, quercitrin and rutin was also examined for comparative purposes. Cerebral lipid peroxidation (assessed by TBARS) was induced by iron sulfate (10 μM), sodium nitroprusside (5 μM) or 3-nitropropionic acid (2 mM). Free radical scavenger properties and the chemical composition of plant extracts were assessed by 1′-1′ Diphenyl-2′ picrylhydrazyl (DPPH) method and by Thin Layer Chromatography (TLC), respectively. M. officinalis aqueous extract caused the highest decrease in TBARS production induced by all tested pro-oxidants. In the DPPH assay, M. officinalis presented also the best antioxidant effect, but, in this case, the antioxidant potencies were similar for the aqueous, methanolic and ethanolic extracts. Among the purified compounds, quercetin had the highest antioxidant activity followed by gallic acid, quercitrin and rutin. In this work, we have demonstrated that the plant extracts could protect against oxidative damage induced by various pro-oxidant agents that induce lipid peroxidation by different process. Thus, plant extracts could inhibit the generation of early chemical reactive species that subsequently initiate lipid peroxidation or, alternatively, they could block a common final pathway in the process of polyunsaturated fatty acids peroxidation. Our study indicates that M. officinalis could be considered an effective agent in the prevention of various neurological diseases associated with oxidative stress.     

Synthesis and in vitro activity of new tetrahydronaphtho[1,2-b]azepine derivatives against Trypanosoma cruzi and Leishmania chagasi parasites

Series of 2-exo-aryl-1,4-epoxy-2,3,4,5-tetrahydronaphtho[1,2-b]azepines 3a–k and cis-2-aryl-4-hydroxy-2,3,4,5-tetrahydronaphtho[1,2-b]azepines 4a–j were synthesized and evaluated against free and intracellular live forms of Trypanosoma cruzi and Leishmania chagasi parasites using in vitro assays. Cell toxicity was also analyzed on Vero and THP-1 mammalian cell lines. The compounds 3c, 3f, and 4d were the most active against both live forms of T. cruzi parasites with low mammalian cell toxicity. Some compounds were active on free live forms of L. chagasi parasites but none was active on intracellular amastigotes of L. chagasi infecting THP-1 macrophages.     

How might intensification of farming influence dung beetle diversity (Coleoptera: Scarabaeidae) in Maputo Special Reserve (Mozambique)?

There are concerns over the increasing encroachment of humans, domestic livestock, and farming onto Maputo Special Reserve because of the potential for habitat modification. Therefore, differences between an undisturbed area of the reserve and a neighbouring farming area are assessed using dung beetle as indicators. In each of the two areas, pig-dung-baited pitfall traps were used to sample dung beetle assemblages in two contrasting habitats, grassland and forest. Distributional analysis of the 57 species and 36 942 individuals that were captured, showed that species richness, species turnover, relative abundance patterns, and biogeographical composition differed strongly between both habitats and areas under different land usage. However, in analyses that apportion variation, the greatest amounts were related to habitat rather than land usage. Even so, in both habitats, the total and mean number of species per trap was higher in the farmed area than in the reserve although this was a significant trend only in grassland. Furthermore, in grassland, widespread species were better represented in the farmed area than in the reserve whereas in forest, widespread species were poorly represented compared to grassland. Also in forest, Maputaland endemics were better represented in the reserve than in the farmed area. Further work is necessary to separate the different geographical, ecological, and land usage factors responsible for the patterns detected in this preliminary study. Even so, there are clearly differences between the Maputo Special Reserve and the farmed area.     

Integrating gene expression and GO classification for PCA by preclustering

Background  

Gene expression data can be analyzed by summarizing groups of individual gene expression profiles based on GO annotation information. The mean expression profile per group can then be used to identify interesting GO categories in relation to the experimental settings. However, the expression profiles present in GO classes are often heterogeneous, i.e., there are several different expression profiles within one class. As a result, important experimental findings can be obscured because the summarizing profile does not seem to be of interest. We propose to tackle this problem by finding homogeneous subclasses within GO categories: preclustering.