Effects of dopamine, dobutamine, amrinone and milrinone on regional blood flow in isoflurane anesthetized dogs

The effects of cyclic AMP increasing cardiotonics (dopamine, dobutamine, amrinone and milrinone) on the blood flow in most organs were compared using colored microsphere technique in isoflurane-anesthetized dogs. Dopamine increased blood flow in ventricular myocardium. Furthermore dopamine induced the increase in blood flow in intestine and kidney at low to middle dose, but not at high dose. Dobutamine induced the highest increase in blood flow in ventricular myocardium and skeletal muscle among the drugs evaluated at middle and high doses. Amrinone and milrinone increased blood flow in ventricular myocardium almost same with catecholamines, and milrinone decreased vascular resistance moderately in most other organs. Milrinone might be more useful than catecholamines for improvement of congestive heart failure or peripheral circulatory failure accompanied with exceeded vasoconstriction.     

Secondary erythrocytosis associated with schwannoma in a dog

An 11-year-old, spayed female mixed-breed dog showed clinical signs of right forelimb lameness and pain by palpation around the neck. Radiography and computed tomography (CT) revealed an extradural mass at the 6th and 7th cervical vertebrae, which compressed the spinal cord. The mass was surgically removed and histopathologically diagnosed as schwannoma. The dog recovered her normal gait after hemilaminectomy and removal of the mass. Ten months after the surgery, the tumor recurred with absolute erythrocytosis and was surgically removed again. This removal temporarily resolved the erythrocytosis with a decrease in plasma erythropoietin (EPO) concentration. EPO protein was detected immunohistochemically in the tumor cells. Erythrocytosis in this dog may be caused by ectopic EPO produced in the schwannoma tissues.     

Effects of medetomidine-midazolam,acepromazine-butorphanol,and midazolam-butorphanol on induction dose of thiopental and propofol and on cardiopulmonary changes in dogs

OBJECTIVE: To evaluate dose-sparing effects of medetomidine-midazolam (MM), acepromazine-butorphanol (AB), and midazolam-butorphanol (MB) on the induction dose of thiopental and propofol and to examine cardiopulmonary changes in dogs. ANIMALS: 23 healthy Beagles. PROCEDURE: Dogs were administered MM, AB, MB, or physiologic saline (0.9% NaCI) solution (PS) IM, and anesthesia was induced with thiopental or propofol. Cardiopulmonary measurements were obtained before and after administration of medication and 0, 5, 10, and 15 minutes after endotracheal intubation. RESULTS: Induction doses were reduced significantly by preanesthetic administration of MM, AB, and MB (thiopental, 20, 45, and 46% after administration of PS; propofol, 42, 58, and 74% after administration of PS, respectively). Recovery time in dogs administered MM-thiopental or MM-propofol and AB-propofol were significantly prolonged, compared with recovery time in dogs administered PS-thiopental or PS-propofol. Relatively large cardiovascular changes were induced by administration of MM, which were sustained even after the induction of anesthesia. Administration of AB and MB induced cardiovascular changes during and immediately after endotracheal intubation that were significantly decreased by induction with thiopental or propofol. However, mild hypotension developed with AB-propofol. Apnea was observed in dogs administered MM during induction of anesthesia, but most respiratory variables did not change significantly. CONCLUSIONS AND CLINICAL RELEVANCE: Preanesthetic medication with MM greatly reduced the anesthesia induction dose of thiopental and propofol but caused noticeable cardiopulmonary changes. Preanesthetic medication with AB and MB moderately reduced the induction dose of thiopental and propofol and amelio rated cardiovascular changes induced by these anesthetics, although AB caused mild hypotension.     

Above- and belowground carbon stocks of two organic,agroforestry-based oil palm production systems in eastern Amazonia

Ecosystem-level assessments of carbon (C) stocks of agroforestry systems are scarce. We quantified the ecosystem-level C stocks of one agroforestry-based oil palm production system (AFS_P) and one agroforestry-based oil palm and cacao production system (AFS_P+C) in eastern Amazonia. We quantified the stocks of C in four pools: aboveground live biomass, litter, roots, and soil. We evaluated the distribution of litter, roots, and soil C stocks in the oil palm management zones and in the area planted with cacao and other agroforestry species. The ecosystem-C stock was higher in AFS_P+C (116.7 ± 1.5 Mg C ha^?1) than in AFS_P (99.1 ± 3.1 Mg C ha^?1). The total litter-C stock was higher in AFS_P+C (3.27 ± 0.01 Mg C ha^?1) than in AFS_P (2.26 ± 0.06 Mg C ha^?1). Total root and soil C stocks (0–30 cm) did not differ between agroforestry systems. Ecosystem-C stocks varied between agroforestry systems due to differences in both aboveground and belowground stocks. In general, the belowground-C stocks varied spatially in response to the management in the oil palm and non-oil palm strips; these results have important implications for the monitoring of ecosystem-level C dynamics and the refinement of soil management.     

Global warming impacts of the process to utilize digested slurry from methane fermentation as a fertilizer: Case Study of the Yamada Biomass Plant

Greenhouse gas (GHG) emissions from the process to utilize digested slurry from methane fermentation as a fertilizer were calculated with actual operational data from a methane fermentation plant and the effects were verified by introducing the process into a field system. The results indicated that the total emissions from the utilization of digested slurry as a fertilizer were 8.1 kg-CO₂ eq. per 1 ton of digested slurry and transportation was the major source of GHG emissions, accounting for 67 % of the total emissions. Shortening the transportation distance by using digested slurry in farmlands near the methane fermentation plant is the most effective to reduce GHG emissions. The results also indicated that GHG emissions from the wastewater treatment process for digested slurry were much larger than GHG emissions from the utilization of digested slurry as a fertilizer. In conclusion, CH₄ as an energy source and digested slurry as a fertilizer can be effectively utilized and reduce GHG emissions by introducing the methane fermentation processes to the use of digested slurry as a fertilizer.     

Suppressive effect of hyaluronan on chondrocyte apoptosis in experimentally induced acute osteoarthritis in dogs

Dogs receiving anterior cruciate ligament transection (ACLT) were treated with either intravenous (IV) or intraarticular (IA) administration of hyaluronan (HA), and differences in appearance of chondrocyte apoptosis of the stifle joint were investigated. Chondrocyte apoptosis was detected using flow cytometry as well as by staining with TdT-mediated dUTP nick end labeling (TUNEL). The percentage of apoptotic chondrocytes in dogs with ACLT was significantly higher than that in intact (non-ACLT) dogs. Dogs treated with IA or IV injection of HA after ACLT had fewer apoptotic chondrocytes than non-treated dogs after ACLT. It was suggested that ACLT-induced apoptosis of chondrocytes was suppressed by HA administration of either IA or IV.     

Effect of maturation culture period of oocytes on the sex ratio of in vitro fertilized bovine embryos

It has been suggested that the maturational stage of oocytes at time of insemination influences the sex ratio of resulting embryos. However, there are very few reports concerning the relationship between the maturation culture period of oocytes and the sex ratio of resulting embryos. The objective of this study was to investigate the effects of in vitro maturation culture period for bovine oocytes on the sex ratio of in vitro produced blastocysts using a novel technique of loop-mediated isothermal amplification (LAMP). Cumulus-oocyte complexes were collected from the ovaries of slaughtered cows, and then matured in vitro for various periods (16, 22, 28, and 34 h). After maturation culture for each period, the oocytes were inseminated with frozen-thawed spermatozoa, and then cultured in vitro. Blastocysts were harvested on Day 7 after insemination, and the sex of the embryos was examined using the LAMP method. The rates of oocytes matured to the metaphase II stage were significantly lower (P < 0.05) in the 16-h maturation group than in the other groups. The proportion of blastocyst formation after insemination was significantly higher (P < 0.05) in the 22-h maturation group than in the other groups. The proportion of male blastocysts increased with the increase in maturation culture period. The proportion of male blastocysts derived from oocytes matured for 34 h was significantly higher (P < 0.05) than from oocytes matured for 16 and 22 h. These results indicate that the sex ratio of in vitro fertilized embryos is apparently influenced by the maturation culture period of the oocytes.     

The effects of propofol, isoflurane and sevoflurane on vecuronium infusion rates for surgical muscle relaxation in dogs

OBJECTIVE: To compare the constant rate infusion (CRI) of vecuronium required to maintain a level of neuromuscular blockade adequate for major surgeries, e.g. thoracotomy or laparotomy, in dogs anaesthetized with a CRI of fentanyl and either propofol, isoflurane or sevoflurane. STUDY DESIGN: Prospective, randomized, cross-over study. ANIMALS: Thirteen male beagles (age, 9-22 months; body mass 6.3-11.3 kg). MATERIALS AND METHODS: Dogs were anaesthetized with propofol (24 mg kg(-1) hour(-1) IV CRI; group P), isoflurane (1.3% end-tidal concentration; group I) or sevoflurane (2.3% end-tidal concentration; group S) with fentanyl (5 microg kg(-1) hour(-1) IV, CRI). Sixty to seventy minutes after induction of anaesthesia, vecuronium was administered at a rate of 0.4, 0.3 and 0.2 mg kg(-1) hour(-1) in groups P, I and S respectively. To determine the degree of neuromuscular block, a peripheral nerve was stimulated electrically using the train-of-four (TO4) stimulus pattern. Evoked muscle contractions were evaluated using a neuromuscular monitoring device. Once the TO4 ratio reached 0, the continuous infusion rate was decreased and adjusted to maintain a TO4 count of 1. Continuous infusion was continued for 2 hours. The infusion rate of vecuronium was recorded 20, 40, 60, 80, 100 and 120 minutes after the start of infusion. RESULTS: The mean continuous infusion rates of vecuronium during stable infusion were 0.22 +/- 0.04 (mean +/- SD), 0.10 +/- 0.02 and 0.09 +/- 0.02 mg kg(-1) hour(-1) in groups P, I and S respectively. There were statistically significant differences between the rates in groups P and I and between the rates in groups P and S. Conclusions and clinical relevance In healthy dogs, the recommended maintenance infusion rate of vecuronium is 0.2 mg kg(-1) hour(-1) under CRI propofol-fentanyl anaesthesia and 0.1 mg kg(-1) hour(-1) during CRI fentanyl-isoflurane or sevoflurane anaesthesia.     

Comparison of feasibility and safety of epidural catheterization between cranial and caudal lumbar vertebral segments in dogs

To compare the technical difficulty and safety of epidural catheterization between cranial and caudal lumbar region, thirteen dogs were randomly assigned to a cranial lumbar group (group CraL, n=6) or a caudal lumbar group (group CauL, n=6) depending on different epidural sites, and one dog was used as a negative control without catheterization. After general anesthesia, an epidural catheter was advanced 10 cm cranially from the interspace of L1-L2 in group CraL or from lumbosacral space in group CauL. Dogs were euthanized and catheter position and tip location were confirmed by laminectomy. Spinal cord samples were examined by macro- and microscopic observations. Success rate, time taken for epidural space confirmation and catheter insertion were compared, and overall technical difficulty was evaluated subjectively. Epidural catheter was inserted successfully in all dogs. Time needed from needle skin puncture to catheter placement and saline injection was 226 ± 63 and 229 ± 26 sec in groups CraL and CauL without significant differences. Three dogs in group CraL suffered subcutaneous blood, but no spinal cord injuries were found. Subjective evaluation score of the overall technical difficulty was slightly but significantly higher in group CraL than in group CauL (P=0.009). Epidural catheterization in cranial lumbar region could be performed as feasible and safe as that at the caudal lumbar vertebral region in medium or large dogs.