Effect of routine cardiovascular catheterization on cardiac troponin I concentration in dogs

ObjectiveTo determine changes in cardiac troponin I concentration (cTnI) associated with cardiovascular catheterization in dogs.Animals, materials and methodscTnI was measured after transarterial coil embolization of patent ductus arteriosus (PDA), balloon valvuloplasty (BV), and pacemaker implantation (PACE). Dogs undergoing ovariohysterectomy (OHE) were used as a control, with 15 animals in each group. Blood for the cTnI assay was collected at baseline (T0), at 5 h (T5), 24 h (T24) and 10 days (T240) post-procedure. The effects of age, duration and difficulty of the procedure were evaluated.ResultsThere was no difference in cTnI concentration at T0 for any of the groups. There was a significant increase in cTnI concentration for BV and PACE, but not PDA at T5 and T24. PACE at T24 and T240 also had higher cTnI than control. Dogs with longer procedure times had significantly higher concentration of cTnI. There was no correlation between the difficulty of the procedure or peri-procedure complications and cTnI.ConclusioncTnI increased during some cardiovascular catheterization procedures, but returned to normal values at 24–240 h. Patients undergoing long catheterization procedures have increased risk for myocardial injury, but this was not related to short-term prognosis.     

Assessment of cardiac output measurement in dogs by transpulmonary pulse contour analysis

Objective – To determine if metatarsal artery pressure (COmet) is comparable to femoral artery pressure (COfem) as the input for transpulmonary pulse contour analysis (PiCCO) in anesthetized dogs, using the lithium dilution method (LiDCO) as a standard for cardiac output (CO) measurement. Design – Prospective randomized study. Setting – University research laboratory. Animals – Ten healthy purpose‐bred mixed breed dogs were anesthetized and instrumented to measure direct blood pressure, heart rate, arterial blood gases, and CO. Interventions – The CO was measured using LiDCO and PiCCO techniques. Animals had their right femoral and left distal metatarsal artery catheterized for proximal (COfem) and distal (COmet) PiCCO analysis, respectively. Measurements were obtained from each animal during low, normal, and high CO states by changing amount of inhalant anesthetics and heart rate. Measurements were converted to CO indexed to body weigh (CI_BW=CO/kg) for statistical analysis. Agreement was determined using Bland and Altman analysis and concordance correlation coefficients. Measurements and Main Results – Thirty paired measurements were taken. The LiDCO CI_BW (± SD) was 68.7 ± 30.3, 176.0 ± 53.0, and 211.1 ± 76.5 mL/kg/min during low, normal, and high CO states, respectively. There was a significant effect of CI_BW state on bias and relative bias with COmet (P<0.001 and P=0.003, respectively). Bias of the COmet method (± SD) was ?116.6 (70.5), 20.1(76.4), and 91.3 (92.0) mL/kg/min at low, normal, and high CI_BW, respectively. Bias of the COfem (± SD) was ?20.3 (19.0), 8.6 (70.9), and ?2.9 (83.0) mL/kg/min at low, normal, and high CI_BW, respectively. The mean relative bias for COfem was ?6.7 ± 44% (limits of agreements: ?81.2 to 67.9%). Conclusion – Compared with lithium dilution, the pulse contour analysis provides a good estimation of CO, but requires femoral artery catheterization in anesthetized dogs.     

Assessing coincidence between priority conservation areas for vertebrate groups in a Mediterranean hotspot

The effectiveness of selecting umbrella species or groups of species to protect other groups is a key and unresolved issue in conservation planning. We detected areas important to the four groups of terrestrial vertebrates inhabiting Andalusia (southern Spain) according to four conservation-value criteria, i.e., richness, rarity, vulnerability, and endemicity. We calculated coincidences between criteria and taxa by the degree of correlation and fuzzy overlap between the different criteria for the same group (intra-group coincidence) and between the different groups of species for the same criteria (inter-group coincidence). For the groups to be appropriate umbrella species, inter-group coincidence should be high. The results showed that intra-group coincidence was high, but inter-group coincidence was low. Thus, zones of importance to each group of species tended to be located in different places compared to the other groups, and therefore none of them should be used as an indicator or umbrella group to protect the others. This result has implications for conservation policy, as the Andalusian authorities should not assume that protecting a site important to one group of species will also be relevant to conserve the other groups. Nevertheless, we identified the areas of relatively high conjoint importance for all the groups, and the best umbrella group in this region, which proved to be reptiles.     

Noise Reversion in Paced Dogs

Pacemakers are commonly implanted by veterinary cardiologists in dogs with bradyarrhythmias. In the past, these pacemakers were placed with little attention to programming except for the basic heart rate. However, the availability of pacing programmers has permitted a better appreciation of the needs for proper and safe pacing in dogs. An awareness of the problems that can result from improper programming is imperative. We report the identification of noise reversion (inappropriate asynchronous pacing) in 42% of dogs consecutively paced (n = 19) at Cornell University during a 2 year period. Noise reversion is the operation that causes the pacemaker to switch to asynchronous pacing with repetitive refractory sensing. It was developed as a protective mechanism against noise being mistaken for cardiac events with the consequence of inhibition of pacing. However, in the dog, this operation can cause inappropriate, and potentially dangerous pacing. In the dog, this common complication is associated with the coexistence of a bradycardia and tachycardia. Proper programming of the refractory period (shortening) in conjunction with the sensitivity (decreasing the sensitivity) can eliminate noise reversion in dogs with both ventricular and atrial pacing.     

Production of a high percentage of male offspring in growth-enhanced transgenic tilapia using Oreochromis aureus ZZ selected pseudofemales

Gene transfer has offered a new tool for the development of improved fish strains for aquaculture. Monosex fish populations could minimize the impact of genetically modified organisms in the environment. In Oreochromis aureus, the use of pseudofemale spawners (sex-reversed male with a female phenotype) is an alternative technique for producing genetically male tilapia offspring. O. aureus fry were treated with 17β-estradiol at 100 mg/kg of food for 45 days. We obtained 77.1% females and 45.9% in the control group. Females randomly taken from the treated group were crossed with normal males. Fry from pseudofemales producing more than 90% male progenies were submitted to 17 β-estradiol treatment to obtain F₂ pseudofemales. The results of the sex-reversal were low and variable ranging between 66.0 and 84.3% females. F₂ pseudofemales were crossed with transgenic males from the F70 line (O. aureus × O. urolepis hornorum) and non-transgenic (O. aureus) males. The sex ratio of progeny of F₂ pseudofemale deviated significantly (P < 0.01) in favor of males in the crosses with transgenic (90.2%) and non-transgenic (89.3%) males compared to the results observed with normal females (51.0 and 52.3%, respectively). The mean fry production with pseudofemales (per m²/day) was similar to the normal females in the crosses with transgenic and non-transgenic males. To our knowledge this is the first report on the production of a near monosex population in genetically modified fish.     

Accumulation, biotransformation, histopathology and paralysis in the Pacific calico scallop Argopecten ventricosus by the paralyzing toxins of the dinoflagellate Gymnodinium catenatum

The dinoflagellate Gymnodinium catenatum produces paralyzing shellfish poisons that are consumed and accumulated by bivalves. We performed short-term feeding experiments to examine ingestion, accumulation, biotransformation, histopathology, and paralysis in the juvenile Pacific calico scallop Argopecten ventricosus that consume this dinoflagellate. Depletion of algal cells was measured in closed systems. Histopathological preparations were microscopically analyzed. Paralysis was observed and the time of recovery recorded. Accumulation and possible biotransformation of toxins were measured by HPLC analysis. Feeding activity in treated scallops showed that scallops produced pseudofeces, ingestion rates decreased at 8 h; approximately 60% of the scallops were paralyzed and melanin production and hemocyte aggregation were observed in several tissues at 15 h. HPLC analysis showed that the only toxins present in the dinoflagellates and scallops were the N-sulfo-carbamoyl toxins (C1, C2); after hydrolysis, the carbamate toxins (epimers GTX2/3) were present. C1 and C2 toxins were most common in the mantle, followed by the digestive gland and stomach-complex, adductor muscle, kidney and rectum group, and finally, gills. Toxin profiles in scallop tissue were similar to the dinoflagellate; biotransformations were not present in the scallops in this short-term feeding experiment.     

Assessing uncertainty of semi‐intensive production of whiteleg shrimp (Litopenaeus vannamei) using partial harvesting programs

We used stochastic models for analysis of the uncertainty involved in semi‐intensive production of shrimp in Nayarit state, Mexico, incorporating partial harvests. Analysis of the database showed that increasing the number of harvests was associated with lower stocking densities, the use of larger ponds, longer cultivation periods, larger final weight of shrimp and total production. Equivalence tests showed that the models adequately fitted the primary data. Monte Carlo simulations indicated that improving management by controlling stocking density and the duration of cultivation increased mean production from 981 to 2573 kg/ha (one partial harvest), from 1808 to 3602 kg/ha (two partial harvests) and from 1364 to 3834 kg/ha (three partial harvests), closely approaching the yields reported in the database. When conducting one and three partial harvests, improved management increased production and the certainty in obtaining the crops, as indicated by diminishing values of the coefficient of variation in output probability distributions. When conducting two partial harvests, however, improved management increased yields, but also increased uncertainty because there was a lower control on production parameters. This does not necessarily imply more uncertainty when conducting two harvests, but that at this stage of knowledge, the primary data only allows detecting limited control on production. Results of a preliminary economic evaluation showed that net revenues ranged from USD$ 2361.1–3488.9, the benefit‐cost ratio from 1.47 to 1.62 and that the best and worse results were obtained by conducting two and one partial harvests. We conclude that the models are useful for analysing uncertainty of semi‐intensive shrimp production incorporating partial harvesting.