Arthritogenicity ofYersinia enterocolitica O:8 in Hamsters: Analysis of the immune response

An animal model, hamster, was used for the study ofYersinia-induced arthritis. The development of arthritis, estimated by measuring the inflammation on hind paws after infection, was correlated with the kinetics of the immune response. Hostological and immunofluorescence (IFI) studies and serum antibody measurements were performed. Two inflammatory peaks were observed: an acute one on day 11 post-infection (p.i) and a chronic one on days 26–35 p.i. Joint cultures were positive until day 14 p.i. IFI was used to demonstrate the deposit of bacterial antigens in the joint. A persistent response of cellular extract-specific IgG antibodies was observed until day 94. Lipopolysaccharide-specific IgG was statistically significant on day 26 p.i. Antibodies against bands 66 and 54 were observed by immunoblotting. Polyclonal activation was detected during reactive arthritis. It is shown thatY. enterocolitica is arthritogenic in hamsters, immune mechanisms participating in the development of this disease.     

Fluoxetine Action on Murine T-Lymphocyte Proliferation: Participation of PKC Activation and Calcium Mobilisation

The present study was undertaken to analyse the effect of fluoxetine upon murine T-lymphocyte proliferation. We found that fluoxetine exerted a dual effect, which depended on the degree of lymphocyte activation: at mitogenic concentration (2 μg/mL) of concavalin A (Con A), we observed an inhibitory effect on cellular proliferation, whereas, on submitogenic Con A concentration (1 μg/mL), fluoxetine stimulated the cellular response. Given these facts, we studied PKC activation and calcium mobilisation in both stimulatory and inhibitory effects of fluoxetine on T-cell proliferation. We observed that fluoxetine increased PKC translocation obtained with 1 μg/mL Con A concentration, whereas PKC was degraded when 2 μg/mL was used. This mechanism is thought to be mediated by calcium mobilisation. According to our results, fluoxetine seemed to modulate calcium influx, which, in turn, would influence PKC translocation, modulating the immune response.     

Intracellular Signals Coupled to Muscarinic Acetylcholine Receptor Activation in Cerebral Frontal Cortex from Hypoxic Mice

1. The aim of the present work was to determine hypoxia-induced modifications in the cascade of intracellular events coupled to muscarinic acetylcholine receptor (mAChR) activation in brain. For this purpose, enzymatic activities were measured on normoxically incubated frontal cortical slices from mice exposed to hypobaric hypoxia for 72 hr.2. We found that hypoxia induced alterations in several cerebral enzymatic basal activities: it increased nitric oxide synthase (NOS), but it decreased both membrane protein kinase C (PKC) and phospholipase C activities.3. The mAChR agonist carbachol was found to increase phosphoinositide hydrolysis to greater values in hypoxic tissues than those found in normoxic conditions. Furthermore, a greater translocation of PKC in response to carbachol was observed in hypoxic tissues than in normoxic ones.4. Besides, carbachol induced a drastic reduction of NOS activity in hypoxic brains, at concentrations that stimulated this enzyme activity in normoxic preparations. In the latter, inhibition is obtained only with high concentrations of the cholinergic muscarinicagonist.5. These results pointed to a carbachol-mediated mAChR hyperactivity induced by hypoxic insult.6. The possibility that these effects would account for a compensatory mechanism to diminish NOS hyperactivity, probably protecting for NO neurotoxic action in hypoxic brain, is also discussed.     

New species of bees of Cuba and La Espanola (Hymenoptera: Colletidae,MEgachilidae, Apidae)

Five new species of Antillean bees are described and illustrated: Colletes granpiedrensis n. sp. (Cuba) (Colletidae) is characterized as follows: Head and mesosoma black, legs and metasoma brown. Dense brown hairs on head and mesosoma; white on frons and metasomal terga. Clypeus, frons and mesosoma with large punctures, lesser on vertex and metasoma. Malar space more wide than long. Male and female slightly similar, except in the apical margin of clypeus, supraclipeal area, and color of the pubescence on legs and sterna; Osmia (Diceratosmia) stangei n. sp. (Dominican Republic) (Megachilidae) is characterized as follows: Dark metallic green, metasoma black with metallic green reflections. Pubescence light; body with large, closed punctures. Female with violet reflections in tergum III and mandible tridentate; Coelioxys (Cyrtocoelioxys) alayoi n. sp. (Cuba) (Megachilidae) is characterized as follows: Female black, except basal area of mandibles, tegula, legs, lateral area of tergum I and sterna, reddish brown. Posterior margin of scutellum rounded. Apex of tergum VI with spine curved up. Sternum VI fringed with short, closed setae, and the apex with short spine; Coelioxys (Boreocoelioxys) sannicolarensis n. sp. (Cuba) (Megachilidae) is characterized as follows: Black, except antenna and tegula brown; legs and sterna reddish brown. Clypeal margin straight in profile. Gradular grooves on metasomal terga II and III distinct medially. Fovea on metasomal tergum II of male deep and short, and Triepeolus nisibonensis n. sp. (Dominican Republic) (Apidae) is characterized as follows: Dorsal pubescence (short and dense) on mesosoma and metasoma from white to yellow, according to specimen; ventral pubescence white. Tergal bands of hairs interrupted medially; two spots of light pubescence on tergum II. Male metasomal sternum VII with anterior margin V-shaped and basal constriction narrow.     

Immunochemotherapy in American cutaneous leishmaniasis: immunological aspects before and after treatment

In this study, we evaluated the immune response of patients suffering from cutaneous leishmaniasis treated with two distinct protocols. One group was treated with conventional chemotherapy using pentavalent antimonium salts and the other with immunochemotherapy where a vaccine against cutaneous leishmaniasis was combined with the antimonium salt. Our results show that, although no differences were observed in the necessary time for complete healing of the lesions between the two treatments, peripheral blood mononuclear cells from patients treated by chemotherapy showed smaller lymphoproliferative responses at the end of the treatment than those from patients in the immunochemotherapy group. Furthermore, IFN-gamma production was also different between the two groups. While cells from patients in the chemotherapy group produced more IFN-gamma at the end of treatment, a significant decrease in this cytokine production was associated with healing in the immunochemotherapy group. In addition, IL-10 production was also less intense in this latter group. Finally, an increase in CD8+ -IFN-gamma producing cells was detected in the chemotherapy group. Together these results point to an alternative treatment protocol where healing can be induced with a decreased production of a potentially toxic cytokine.     

MitoTimer

Fluorescent Timer, or DsRed1-E5, is a mutant of the red fluorescent protein, dsRed, in which fluorescence shifts over time from green to red as the protein matures. This molecular clock gives temporal and spatial information on protein turnover. To visualize mitochondrial turnover, we targeted Timer to the mitochondrial matrix with a mitochondrial-targeting sequence (coined “MitoTimer”) and cloned it into a tetracycline-inducible promoter construct to regulate its expression. Here we report characterization of this novel fluorescent reporter for mitochondrial dynamics. Tet-On HEK 293 cells were transfected with pTRE-tight-MitoTimer and production was induced with doxycycline (Dox). Mitochondrial distribution was demonstrated by fluorescence microscopy and verified by subcellular fractionation and western blot analysis. Dox addition for as little as 1 h was sufficient to induce MitoTimer expression within 4 h, with persistence in the mitochondrial fraction for up to 6 d. The color-specific conformation of MitoTimer was stable after fixation with 4% paraformaldehyde. Ratiometric analysis of MitoTimer revealed a time-dependent transition from green to red over 48 h and was amenable to analysis by fluorescence microscopy and flow cytometry of whole cells or isolated mitochondria. A second Dox administration 48 h after the initial induction resulted in a second round of expression of green MitoTimer. The extent of new protein incorporation during a second pulse was increased by administration of a mitochondrial uncoupler or simvastatin, both of which trigger mitophagy and biogenesis. MitoTimer is a novel fluorescent reporter protein that can reveal new insights into mitochondrial dynamics within cells. Coupled with organelle flow cytometry, it offers new opportunities to investigate mitochondrial subpopulations by biochemical or proteomic methods.     

Influence of Cinnamon and Catnip on the Stereotypical Pacing of Oncilla Cats (Leopardus tigrinus) in Captivity

Nonhuman animals in captivity can experience environmental privation that results in their exhibiting abnormal behaviors. Environmental enrichment techniques can help improve their welfare. This study investigated the behavior of 8 zoo-housed oncilla cats (Leopardus tigrinus) in response to 2 odors (catnip and cinnamon) introduced individually into the animals' enclosures for 3 consecutive days. Proportion of scans spent engaging in stereotypical pacing were compared before, during, and after treatments. The addition of cinnamon reduced the proportion of pacing during and after enrichment (Wilcoxon: Z = 3.16, p < .001; Z = 3.16, p < .001, respectively), indicating a prolonged effect of the enrichment on the animals' behavior. Catnip appears to have elicited no significant difference in the stereotypic pacing before, during, or after the enrichment (Friedman: X² = 2.69; p = .260). The results highlight the potential use of cinnamon as a method of environmental enrichment for small captive-housed cats.