Combined effects of dexmedetomidine and vatinoxan infusions on minimum alveolar concentration and cardiopulmonary function in sevoflurane-anesthetized dogs

ObjectiveTo evaluate the effects of combined infusions of vatinoxan and dexmedetomidine on inhalant anesthetic requirement and cardiopulmonary function in dogs.Study designProspective experimental study.MethodsA total of six Beagle dogs were anesthetized to determine sevoflurane minimum alveolar concentration (MAC) prior to and after an intravenous (IV) dose (loading, then continuous infusion) of dexmedetomidine (4.5 μg kg^–1 hour^–1) and after two IV doses of vatinoxan in sequence (90 and 180 μg kg^–1 hour^–1). Blood was collected for plasma dexmedetomidine and vatinoxan concentrations. During a separate anesthesia, cardiac output (CO) was measured under equivalent MAC conditions of sevoflurane and dexmedetomidine, and then with each added dose of vatinoxan. For each treatment, cardiovascular variables were measured with spontaneous and controlled ventilation. Repeated measures analyses were performed for each response variable; for all analyses, p < 0.05 was considered significant.ResultsDexmedetomidine reduced sevoflurane MAC by 67% (0.64 ± 0.1%), mean ± standard deviation in dogs. The addition of vatinoxan attenuated this to 57% (0.81 ± 0.1%) and 43% (1.1 ± 0.1%) with low and high doses, respectively, and caused a reduction in plasma dexmedetomidine concentrations. Heart rate and CO decreased while systemic vascular resistance increased with dexmedetomidine regardless of ventilation mode. The co-administration of vatinoxan dose-dependently modified these effects such that cardiovascular variables approached baseline.Conclusions and clinical relevanceIV infusions of 90 and 180 μg kg^–1 hour^–1 of vatinoxan combined with 4.5 μg kg^–1 hour^–1 dexmedetomidine provide a meaningful reduction in sevoflurane requirement in dogs. Although sevoflurane MAC-sparing properties of dexmedetomidine in dogs are attenuated by vatinoxan, the cardiovascular function is improved. Doses of vatinoxan >180 μg kg^–1 hour^–1 might improve cardiovascular function further in combination with this dose of dexmedetomidine, but beneficial effects on anesthesia plane and recovery quality may be lost.     

Adaptation of ostriches to transport‐induced stress: Physiometabolic response

This study assessed the effects of five different transport periods on physiometabolic responses and gas exchange in ostriches. It included 138 ostriches that were assigned to five experimental groups. G₁ included 78 birds that were set aside as a reference group (RG). Each one of the four remaining experimental groups included 20 ostriches, which were transported in the following manner: G₁ on one occasion for a period of 1 h; G₂ on one occasion for 2 h; and G₃ on one occasion for 3 h; G_4a was made up of the ostriches from G₁ but they were shipped on a second occasion, for 2 h (making a total of 3 h); finally, G_4b was that same group, but after a third transport period, on this occasion during 3 h (for a total of 6 h). Groups G₂ and G₃ presented the most marked blood alterations (P < 0.05), including an increase in pH, hypocapnia (27.8 ± 0.80 mmHg), hypernatremia (171.75 ± 1.84 mmol/L), hypocalcemia (0.95 ± 0.03 mmol/L), and hyperglycemia (224.05 ± 3.94 mg/dL). Also, group G₃ presented the lowest hematocrit values (26.5 ± 0.47 HTC%). Therefore, transporting ostriches with no prior experience for 3 h caused the most pronounced physiometabolic changes.     

Seroprevalence of Toxoplasma gondii infection in sheep and alpacas (Llama pacos) in Chile

Serum samples from 408 sheep from different regions of Chile and 447 alpacas (Llama pacos) from the north of the country were tested for Toxoplasma gondii antibodies. The indirect haemagglutination test (IHAT) was used in both species and the indirect immunofluorescence test (IIFT) was also used on the sheep samples in order to compare the performance of the tests in that species. In both tests, titers ≥1:16 were considered diagnostically significant. Sera from 49 sheep (12%) were positive to T. gondii antibodies by the IHAT. When using the IIFT, 114 sheep sera (28%) were positive. The different results obtained in sheep sera between the tests were significant (p<0.0001). No differences were observed between geographical locations or sex of the sampled sheep regarding serological detection of T. gondii antibodies in sheep. As expected, adult sheep showed higher T. gondii reactivity than young sheep (p=0.0008). The corrected prevalence of toxoplasmosis in alpaca was 16.3% (32 positive out of 447). The rather low prevalence in alpacas may be associated with their extensive management as well as the extreme climatic conditions of The Andes which apparently would not be favorable for the transmission of the parasite.     

Suppression of Food Intake in Triatoma infestans by N-Substituted Methyl Maleamates

A series of methyl esters of N-substituted (Z)- and (E)-maleamic acids were synthesized and their effect on food intake measured on fifth-instar nymphs of Triatoma infestans. Suppression of food intake was found only for the (Z)-isomers. The initial reaction rate of the synthesized compounds with glutathione (GSH) was calculated from the reaction in vitro of the (Z)-isomers. No reaction was observed with the (E)-isomers. Good correlation between the suppression of food intake, measured by its ED₅₀ (effective dose that inhibited feeding of 50% of the population) and the initial reaction rate with GSH and the hydrophobic parameter π, was found. © of SCI.     

ULTRASONOGRAPHIC DIAGNOSIS OF OVINE CYSTIC ECHINOCOCCOSIS

The sanitary and economic impact of cystic echinococcosis is serious in those countries where it becomes endemic. Ultrasonography is one technique that may be used to diagnose this disease in endemic areas. In parasitized sheep, hydatid cysts appear sonographically as a round hypoechoic structure. Twenty two sheep destined for slaughter were studied sonographically and imaging findings compared to post-mortem findings. Three sheep with hydatid cysts were identified. Eighty additional sheep not destined for slaughter were also studied. Echinococcus granulosus cysts were detected in three animals. Forty sheep from a non-endemic area had no hepatic cysts. The in vivo sonographic study of sheep provides a useful screening tool for echinococcosis.     

Validity of the Enzyme-linked Immunoelectrotransfer Blot (EITB) for naturally acquired porcine cysticercosis

The Enzyme-linked Immunoelectrotransfer Blot (EITB) has been used widely as a screening test for Taenia solium cysticercosis in swine. However, the relation between seropositivity and infection in pig populations from endemic areas has not been well defined. The aim of this study is to relate EITB seropositivity with infection and infection burden, analyse the trade-off between sensitivity and specificity with various cut-off points for the EITB assay, and finally describe the serology changes in a cohort of rural pigs raised under natural conditions. A group of 107 pigs that were used as controls during a vaccination field trial in Peru was our study population. The prevalence of porcine cysticercosis determined by necropsy examination was 16.82% (18/107) in these animals. Using EITB reactivity to ≥1 band as a cut-off point for the assay, the sensitivity was 88.89% (65.29–98.62, 95% CI) and the specificity was 48.31% (37.59–59.16, 95% CI). Comparing other cut-off points, involving up to as many as 7 reactive bands, a reactivity of ≥3 bands provided the best trade-offs in sensitivity and specificity. Using this cut-off point for the assay, the sensitivity was 77.77% (52.36–93.59, 95% CI) and the specificity was 76.40% (66.22–84.76, 95% CI). A significant association was found between cyst counts over 100 cysts and reactivity to ≥3 bands in the EITB assay (Fisher's exact test, p < 0.05). The results of this study suggest that the use of the EITB assay to study porcine cysticercosis may require setting different cut-offs under field and experimental conditions, and depending upon the objective of the screening process.     

Productivity is a poor predictor of plant species richness

For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters(-2)) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity and richness.     

Impacts of fishing low-trophic level species on marine ecosystems

Low-trophic level species account for more than 30% of global fisheries production and contribute substantially to global food security. We used a range of ecosystem models to explore the effects of fishing low-trophic level species on marine ecosystems, including marine mammals and seabirds, and on other commercially important species. In five well-studied ecosystems, we found that fishing these species at conventional maximum sustainable yield (MSY) levels can have large impacts on other parts of the ecosystem, particularly when they constitute a high proportion of the biomass in the ecosystem or are highly connected in the food web. Halving exploitation rates would result in much lower impacts on marine ecosystems while still achieving 80% of MSY.     

IHHN Virus as an Etiological Factor in Runt-Deformity Syndrome (RDS) of Juvenile Penaeus vannamei Cultured in Hawaii

Runtdeformity syndrome (RDS) is an economically significant, frequent disease problem of cultured Penaeus vannamei . RDS is characterized by variable, often greatly reduced, growth rate of up to 30% of a cultured population and many shrimp with cuticle deformities of the rostrum, anterior appendages or other parts. The cause of RDS is undetermined.
Nursery trials comparing histologically IHHN-positive and histologically IHHN-negative Penaeus vannamei cultured under identical conditions were conducted at The Oceanic Institute. The IHHN-positive populations developed RDS symptoms including increased individual size variation, reduced population growth, and high prevalance of rostrum, antennae or cuticle deformity, while the IHHN-negative groups displayed none of these symptoms. No other diseases or parasites were identified in the IHHN-positive populations that would account for the RDS symptoms.
A single commercialele nursery was stocked with histologidly IHHN-positive P. vannamei and a high prevalence of RDS was observed. Shrimp growth was bimodal with a subpopulation growing normally and a subpopulation growing slowly. Significant relationships between shrimp harvest size and IHHN prevalance, selected individual organ IHHN severity grades and IHHN severity index (six organs evaluated) were found. Large, apparently normal shrimp were less severely infected with virus and did not display any cuticle deformities.
In sum, these data provide epidemiological and histopathological evidence for the hypothesis that infection by IHHN virus is the cause of RDS in cultured P. vannamei .