Evaluation of three immunoserological techniques in the detection of porcine trichinellosis

Three immunoserological tests (IST) used for the detection of porcine trichinellosis, immunofluorescence (IF), enzyme-inmunoanalysis (EIA), and Western blot (WB), were compared. Three groups of animals were analyzed: Group 1, animals naturally infected with parasite burdens (PB) of <1 muscle larvae (ML)/g (n = 18); Group 2, animals naturally infected with PB of ≥2 ML/g (n = 23); Group 3, animals raised and home-slaughtered on farms in Argentina (n = 59). Animals from Groups 1 and 2 were identified in outbreaks and were analyzed by individual artificial digestion (AD) of ≥30 g of muscle. Animals in Group 3 were subjected to AD of 5 g of muscle.The detection percentages in sera of swine with the lower PB were 100% for IF, 72% for EIA, and 50% for WB. Eighty-three percent of the animals were serologically positive by two or three techniques. In pigs with the higher PB, the detection percentage was similar for IF and EIA (100% vs. 91%, respectively), and was lower for the WB (61%). Ninety-six percent of the animals were serologically positive by two or three techniques. Group 3 animals had similar detection percentages for the three techniques (IF, 30%; EIA, 29%; WB, 42%). Twenty-five percent of the animals were serologically positive by two or three techniques. Two animals were positive by AD with PB of 0.33 and 2.4 ML/g, and were positive for IF and WB, or IF, EIA, and WB. Results indicate that the sensitivity of each technique depends on the PB, and always ranked in sensitivity as IF > EIA > WB. For the lower PB, the decrease in the sensitivity is more pronounced for the EIA. Although the WB has a low sensitivity, the detection of the specific bands for Trichinella spiralis makes it a useful confirmatory tool. Considering that more than 83% of the parasitologically positive animals had 2 or 3 positive serological results using the techniques tested here, for the diagnosis of porcine trichinellosis, pigs positive by two of these serological techniques must be regarded as truly infected pigs.     

Skeletal Muscle for Endomyocardial Biopsy: Comparable Stress Response in Doxorubicin Cardio-myopathy

In the present study, we compared the cell damage response in skeletal and cardiac muscle tissue when exposed to doxorubicin. This was carried out by means of a less invasive informative substitute to endomyocardiac biopsy based on Hsp70 immunodetection and a subcellular analysis of the nucleolus. Male Sprague Dawley rats (62 g body weight) were randomly distributed into 3 group, the control and doxorubicin I and doxorubicin II groups, in which 15 and 25 mg/kg body weight of doxorubicin (0.1 ml, i.v.) was administered, respectively. After 15, 30, 45 and 60 minutes, portions of the left and right ventricle wall and interventricle wall, together with skeletal muscle from the posterior and anterior member, were prepared for Hsp70 immunodetection by Western blot analysis and ultrastructural study using the thin cut technique. Differential cell response between the control and treated groups was observed in Hsp70 immunodetection and at the subcellular level. In the control group, the Hsp70 recognition levels and typical normal nucleolar morphology were similar, while the treated groups showed variable-dependent Hsp70 recognition and segregation of nucleolar components, forming ring-like figures of a variable-independent nature. Comparison of cardiac and skeletal muscle tissue cell response to doxorubicin toxic aggression revealed parallelism in terms of Hsp70 accumulation in certain regions of both tissues (15 mg/kg body weight of doxorubicin), which suggests that replacing endomyocardiac biopsy analysis with skeletal muscle analysis may be a safe option.     

Effect of lidocaine on the minimum alveolar concentration of sevoflurane in dogs

Objective  To investigate the effects of a low-dose constant rate infusion (LCRI; 50 μg kg⁻¹ minute⁻¹) and high-dose CRI (HCRI; 200 μg kg⁻¹ minute⁻¹) lidocaine on arterial blood pressure and on the minimum alveolar concentration (MAC) of sevoflurane (Sevo), in dogs.
Study design  Prospective, randomized experimental design.
Animals  Eight healthy adult spayed female dogs, weighing 16.0 ± 2.1 kg.
Methods  Each dog was anesthetized with sevoflurane in oxygen and mechanically ventilated, on three separate occasions 7 days apart. Following a 40-minute equilibration period, a 0.1-mL kg⁻¹ saline loading dose or lidocaine (2 mg kg⁻¹ intravenously) was administered over 3 minutes, followed by saline CRI or lidocaine LCRI or HCRI. The sevoflurane MAC was determined using a tail clamp. Heart rate (HR), blood pressure and plasma concentration of lidocaine were measured. All values are expressed as mean ± SD.
Results  The MAC of Sevo was 2.30 ± 0.19%. The LCRI reduced MAC by 15% to 1.95 ± 0.23% and HCRI by 37% to 1.45 ± 0.21%. Diastolic and mean pressure increased with HCRI. Lidocaine plasma concentration was 0.84 ± 0.18 for LCRI and 1.89 ± 0.37 μg mL⁻¹ for HCRI. Seventy-five percent of HCRI dogs vomited during recovery.
Conclusion and clinical relevance  Lidocaine infusions dose dependently decreased the MAC of Sevo, did not induce clinically significant changes in HR or arterial blood pressure, but vomiting was common during recovery in HCRI.     

Dietary Selection by Domestic Grazing Ruminants in Temperate Pastures: Current State of Knowledge,Methodologies, and Future Direction

Ruminants grazing mixed-species pastures face many choices, including when and where to graze and how much herbage to consume. These choices affect not only the nutritional status of the animal, but also sward composition and nutritive value through selective defoliation. Limited research has been conducted in the area of dietary selection and preference, most of which has been limited to simple model systems often involving a choice between only two herbage species. Although these studies have provided a vital tool to allow understanding of the fundamental principles of foraging behavior, in reality, grazing ruminants are faced with more complex situations. Understanding and managing animal preferences in mixed swards and thereby altering dietary selection can result in greater primary (plant) and secondary (animal) productivity. Key issues to improve this understanding include a better linking of behavioral and nutritional studies, a better understanding of the genetic factors influencing diet selection, and the development of more explicit spatial models of foraging behavior that incorporate multiple scales of decision making. This article, as part of a set of synthesis articles, reviews the current state of knowledge and research methodologies related to diet selection of grazing domestic ruminants with particular reference to improved temperate grazing environments, including how well we understand each part of the complex decision-making process a grazing ruminant faces, the links with primary and secondary productivity, and developments in methodologies. Finally, we identify key areas where knowledge is lacking and further research is urgently required.     

Effects of blood donation on arterial blood pressure in retired racing Greyhounds

The purpose of this study was to evaluate changes in systolic arterial blood pressure (SABP) immediately after collection of blood for transfusion in retired racing Greyhounds. We prospectively evaluated 19 blood donor Greyhounds before and after the collection of a unit (450 mL) of blood. The SABP was measured with Doppler in the right forearm after the dogs had been in the blood collection room for a few minutes (PRE-FLOOR) and again 5-10 minutes after the dogs were placed on the table where they would be bled (PRE-TABLE). A total of 3-5 minutes after completing the blood collection, the SABP was measured again while the dogs were still in lateral recumbency on the table (POST-TABLE) and once more 60-90 minutes later, when the dogs were on the floor after completing the donation (POST-FLOOR). All dogs were monitored for clinical signs of hypotension, including depression, weakness, collapse, and pallor, for a minimum of 2 hours after donation. There was a significant difference in SABP for the group between PRE-FLOOR and POST-TABLE (P = .02) and between PRE-TABLE and POST-TABLE determinations (P = .01). There were no significant differences for any of the other time points; there were no adverse events. Therefore, we conclude that the collection of 450 mL of blood from normal Greyhounds results in a short-lived yet significant decrease in SABP, but the likelihood of adverse events is negligible.     

Serum creatinine concentrations in retired racing Greyhounds

Background: Greyhounds frequently have laboratory values that are outside reference intervals established for dogs. Our recognition of increased serum creatinine concentrations in several Greyhounds posed a problem when evaluating a Greyhound with suspected renal disease.
Objective: The purpose of this study was to compare serum creatinine concentrations between Greyhound and non-Greyhound dogs.
Methods: Thirty retired racing Greyhounds and 30 age-and gender-matched control non-Greyhound dogs were evaluated. Serum creatinine concentrations in both groups were measured using a standard biochemical method and compared statistically using a Kruskal-Wallis test.
Results: Creatinine concentration was significantly higher in the Greyhounds ( P < .01) than in the control group.
Conclusion: Greyhounds have a higher serum creatinine concentration than do non-Greyhound dogs. This idiosyncrasy should be taken into account when evaluating healthy Greyhounds and those with suspected renal disease.     

In-vitro evidence for activative thiolysis and selfsynergism of sulfenyl dicarbamate derivatives of 3,4 methylenedioxyphenyl N-methylcarbamate

Activative thiolytic cleavage of the N-S bond and self-synergism in sulfenyl dicarbamate (SD) derivatives of 3,4-methylenedioxyphenyl N-methylcarbamate has been investigated. The formation of precursor carbamates by the reaction of the propoxur derivative with glutathione and cysteine was demonstrated by HPLC. The slower rate of insectidal action of SD-propoxur compared with propoxur and its lower ki for inhibition of housefly acetylcholinesterase measured after preincubation of housefly head homogenate with N-ethylmaleimide were considered as indirect evidence of the N-S breakdown as a delay factor in toxicity. The SD-carbaryl derivative, 3,4-methylenedioxyphenyl N-methylcarbamate, and piperonyl butoxide similarly inhibited the oxidative metabolism of [¹⁴C]carbaryl in post-mitochondrial homogenates of housefly abdomens. The results indicated that activative thiolysis and self-synergism performed by the methylenedioxyphenyl group could be processes involved in the insecticidal action of the sulfenyl dicarbamates.     

Time course of endocrine changes in the hypophysis-gonad axis induced by hypobaric hypoxia in male rats

Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male rats. The mechanisms that underlie these changes in testicular function are unknown and could involve changes in the hypophysis-gonad axis. We have tested the hypothesis that changes take place in the endocrine status (FSH, follicle stimulating hormone; LH, luteinizing hormone; testosterone) of rats subjected to CHH. Male Wistar rats were maintained under normobaric or hypobaric conditions (428 torr, 4,600 m). On days 0, 5, 15 and 30 post-exposure, 12 rats were anesthetized, their body weights were measured and blood samples were collected. The testicles were fixed in 4% formaldehyde and processed for histological analysis. In this time course, the FSH levels rose by day 5 post-exposure. On subsequent days, the FSH levels decreased in rats subjected to CHH with a tendency to remain higher than the normoxic group. The LH plasma levels decreased in rats exposed to CHH. Consistent with the decrease in LH levels, the plasma testosterone level decreased significantly after 30 days of CHH exposure. Integrated analysis of hormonal changes in rats subjected to CHH and the body dehydration that occurs in HH allows us to conclude that the effects of CHH on spermatogenesis may be partially related to changes in the hypophysis-gonad hormonal axis.     

Biological activity of dihydroartemisinin in canine osteosarcoma cell lines

OBJECTIVE: To evaluate the biological activity of dihydroartemisinin on canine osteosarcoma cell lines in vitro. SAMPLE POPULATION: 4 canine osteosarcoma cell lines. PROCEDURES: Cell viability assays were performed on canine osteosarcoma cell lines OSCA2, OSCA16, OSCA50, and D17 after 24, 48, and 72 hours of treatment with dihydroartemisinin at concentrations of 0.1 to 100 microM. Apoptosis was assessed by use of an ELISA for free nuclosomal DNA fragmentation and by western blot analysis for cleavage of caspase 3. Cell cycle analysis was performed by use of staining with propidium iodide and flow cytometry. Detection of reactive oxygen species (ROS) was conducted in the D17 cell line by use of 6-carboxy-2',7'-dihydrofluorescein diacetate and flow cytometry. RESULTS: The concentration of dihydroartemisinin required for 50% inhibition of cell viability (IC50) was achieved in all 4 canine osteosarcoma cell lines and ranged from 8.7 to 43.6 microM. Induction of apoptosis was evident as an increase in nucleosomal DNA fragmentation, cleavage of caspase 3, and an increase in the population in the sub G0/G1 phase of the cell cycle detected by flow cytometry. Exposure to dihydroartemisinin also resulted in a decrease in the G0/G1 population. Iron-dependent generation of ROS was detected in dihydroartemisinin-treated D17 cells; ROS generation increased in a dose-dependent manner. CONCLUSIONS AND CLINICAL RELEVANCE: Incubation with dihydroartemisinin resulted in biological activity against canine osteosarcoma cell lines, which included induction of apoptosis and arrest of the cell cycle. Clinical trials of dihydroartemisinin in dogs with osteosarcoma should be conducted.     

Plant growth and yield responses in olive (Olea europaea) to different irrigation levels in an arid region of Argentina

Over the last two decades, a significant increase in intensively managed olive orchards has occurred in the northwest of Argentina where climatic conditions differ greatly from the Mediterranean Basin. Annual amounts of applied irrigation are generally high due to low rainfall, access to deep ground water, and little information about water use by the crop in the region. The objectives of this study were to: (1) assess the responses of plant growth, yield components, and several physiological parameters to five different irrigation levels and (2) determine an optimum crop coefficient (Kc) for the entire growing season considering both fruit yield and vegetative growth. Five irrigation treatments (Kc = 0.50, 0.70, 0.85, 1.0, 1.15) were employed from late winter to the fall over 2 years in a 6-year-old cv. ‘Manzanilla fina’ olive orchard. Tree canopy volume was approximately 15 m³ with a leaf area of about 40 m² at the beginning of the experiment. During much of each year, the volumetric soil water content was lower in the Kc = 0.50 treatment than in the other irrigation levels evaluated (Kc = 0.85 and 1.15). Although differences in midday stem water potential (Ψ_s) were not always apparent between treatments during the first year, there were lower Ψ_s values in Kc = 0.50 and 0.70 relative to the higher irrigation levels during the second year. Shoot elongation in Kc = 0.50 was about 50% of that in Kc = 1.0 and 1.15 during both years leading to significant differences in the increase of tree canopy volume by the end of the first year. Fruit yield was similar among irrigation levels the first year, but yield reached a maximum value the second year between Kc = 0.70 and 0.85 above which no increase was apparent. The somewhat lower fruit yield values in Kc = 0.50 and 0.70 were associated with decreased fruit number rather than reductions in individual fruit weight. The water productivity on a yield basis (fruit yield per mm of applied irrigation) decreased as irrigation increased in the second year, while similar calculations based on trunk cross-sectional area growth indicated that vegetative growth was proportional to the amount of irrigation. This suggests that the warm climate of northwest Argentina (28° S) can induce excessive vegetative growth when very high irrigation levels are applied. A Kc value of approximately 0.70 over the course of the growing season should be sufficient to maintain both fruit yield and vegetative growth at adequate levels. An evaluation of regulated deficit irrigation strategies for table olives in this region could be beneficial to further reduce irrigation.