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Determination of pharmacokinetics and pharmacodynamics of flunixin in calves by use of pharmacokinetic/pharmacodynamic modeling
1995
Landoni, M.F. | Cunningham, F.M.
Pharmacokinetic and pharmacodynamic variables of flunixin were studied in calves after IV administration of the drug at a dose rate of 2.2 mg/kg of body weight. The anti-inflammatory properties of flunixin were investigated, using a model of acute inflammation; this involved surgically implanting tissue cages at subcutaneous sites and stimulating the tissue cage granulation tissue by intracavitary injection of carrageenan. The actions of flunixin on exudate concentrations of several substances related to the inflammatory process, including proteases (metalloprotease [active and total] and cysteine and serine proteases), enzymes (lactate dehydrogenase, acid phosphatase, and beta-glucuronidase [beta-glu]), eicosanoid (prostaglandin E2 [PGE2], leukotriene B4, and serum thromboxane B2 [TXB2]) concentrations, and bradykinin (BK)-induced edema, were investigated. Flunixin had a long elimination half-life--6.87 +/- 0.49 hours--and volume of distribution was 2.11 +/- 0.37 L/kg, indicating extensive distribution of the drug in the body. Body clearance was 0.20 +/- 0.03 L/kg/h. Flunixin exerted inhibitory effects on serum TXB2 and exudate PGE2 concentrations, B-glu activity, and BK-induced swelling. Other enzymes and inflammatory mediators were not significantly affected. Pharmacokinetic/pharmacodynamic modeling of the data revealed similar mean concentration producing 50% of the maximal effect values for inhibition of exudate PGE2 and beta-glu and of BK-induced swelling (0.070 +/- 0.006, 0.064 +/- 0.040, and 0.061 +/- 0.030 microgram/ml), respectively). A lower concentration producing 50% of the maximal effect value was obtained for inhibition of serum TXB2 concentration (0.023 +/- 0.004 microgram/ml). Differences also were observed in equilibration half-life for these actions, suggesting the existence of 3 distribution compartments correlating with 3 sites of action--a central compartment and shallow and deep peripheral compartments. Pharmacokinetic/pharmacodynamic modeling proved to be a useful analytical method, providing a quantitative description of in vivo drug pharmacodynamics and indicating possible mechanisms of action.
Show more [+] Less [-]Role of low dietary fat in the treatment of dogs with exocrine pancreatic insufficiency
1995
Westermarck, E. | Junttila, J.T. | Wiberg, M.E.
The main objective of the study reported here was to determine whether signs typical of exocrine pancreatic insufficiency (EPI) are alleviated when affected dogs are fed a diet with low fat content, compared with feeding ordinary commercial dog food or food prepared by the owner. The most cost-effective amount of enzyme supplement also was estimated. The study consisted of 6 test periods. Duration of the first and third periods was 4 weeks, and that of the others was 2 weeks. During the first 2 periods, the dogs were fed their original diet. The amount of enzyme supplement was reduced by half between the first and the second period. During the last 4 periods, the dogs were fed only the low-fat diet, and amount of the enzyme supplement was reduced stepwise. During the entire study, owners were asked to assess daily the severity of 9 signs typical of EPI. A new index was established by adding the daily scores of each individual EPI sign. This index was designated the EPI index and was used as a measure of the general well-being of the dog. When the mean EPI indexes of the original diet periods were compared with those of the corresponding low-fat diet periods, there were no statistically significant differences by use of Turkeys test or the paired t-test. There was considerable variability between dogs, however. The fat content of the original diet did not correlate with the difference in EPI signs when the dogs were fed the low-fat diet. According to our study, feeding a low-fat diet to dogs with EPI did not significantly alleviate clinical signs of the disease. Decreasing the enzyme supplementation by 50% of the recommended of dose did not significantly increase severity of the cumulative EPI score. Decreasing the enzyme supplement by three-fourths of the recommended dose was excessive, and the severity of the clinical signs increased significantly (P < 0.05) The cost of the low-fat diet, compared with that of the original diet, was high.
Show more [+] Less [-]Effects of giardiasis on production in a domestic ruminant (lamb) model
1995
Olson, M.E. | McAllister, T.A. | Deselliers, L. | Morck, D.W. | Cheng, K.J. | Buret, A.G. | Ceri, H.
Objective: To examine the effects of giardiasis on production and carcass quality, using growing lambs as a domestic ruminant model. Design: Randomized block. Animals: Giardia-free lambs: 23 in infected group, 24 in control group. Procedure: Six-week-old, specific-pathogen-free lambs were infected with Giardia trophozoites; control lambs received saline solution. Clinical signs of infection, body weight, and feed intake were determined for 10 weeks. Carcass weight and quality were determined at slaughter weight of 45 kg. Results: Giardia infection persisted from weeks 7 to 16. For 5 weeks after challenge exposure, abnormal feces were more frequently observed in infected lambs. Giardia infection was associated with a decrease in rate of weight gain and impairment in feed efficiency. Time to reach slaughter weight was extended in infected lambs, and the carcass weight of Giardia-infected lambs was lower than that of control lambs. Conclusion: Giardiasis has a negative effect on domestic ruminant production. Clinical Relevance: Giardiasis in domestic ruminants is an economically important disease, thus necessitating control or elimination of the infection.
Show more [+] Less [-]Comparison of N-acetylcysteine and methylene blue, alone or in combination, for treatment of acetaminophen toxicosis in cats
1995
Rumbeiha, W.K. | Lin, Y.S. | Oehme, F.W.
Acetaminophen is widely used in human beings for analgesic purposes, but is one of the most frequent causes of poisoning in cats. Acetaminophen-poisoned cats develop methemoglobinemia and sometimes hepatic failure. To determine the benefit of using methylene blue, a treatment for methemoglobinemia, along with N-acetylcysteine (NAC), the recommended treatment for acetaminophen-poisoned cats, groups of 3 male and 3 female cats each were given methylene blue NAC, or both after administration of acetaminophen (120 mg/kg of body weight, PO). Male cats seemed more susceptible than female cats to acetaminophen toxicosis, because 3 males died of hepatic failure (2 cats given acetaminophen/methylene blue and 1 given acetaminophen/NAC/methylene blue). Although NAC alone seemed to elicit the best overall response, methylene blue, alone or in combination with NAC, may be useful in female cats.
Show more [+] Less [-]Expression of the endogenous Marek's disease virus ICP4 homolog (MDV ICP4) gene is enhanced in latently infected cells by transient transfection with the recombinant MDV ICP4 gene
1995
Endoh, D. (Hokkaido Univ., Sapporo (Japan)) | Ikegawa, S. | Kon, Y. | Hayashi, M. | Sato, F.
The ICP4 homolog of Marek's disease virus (MDV ICP4) is a possible candidate for the transactivator of the early genes. We transfected MDCC-MSB-1 (MSB-1) tumor cells with plasmid including a coding region of MDV ICP4 using cationic liposome. As carriers for intranulear transport, high mobility group -1 and -2 proteins were bound to the plasmid DNA before forming liposomes. We detected transcripts from the plasmid 2 hr after transfection by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis. We also detected abundant transcripts of endogenous ICP4 2-96 hr after transfection. These data suggested that expression of introduced MDV ICP4 gene enhanced the expression of endogenous MDV ICP4. On the other hand, quantitative PCR analysis for virus genome DNA indicated no significant alteration of copy number of virus genome in transfected MSB-1 cells, suggesting that reactivation of virus requires more than turning on MDV ICP4 gene
Show more [+] Less [-]Effects of supplementation of the maturation media with insulin on in vitro maturation and in vitro fertilization of bovine oocytes
1995
Matsui, M. (Hokkaido Univ., Sapporo (Japan)) | Takahashi, Y. | Hishinuma, M. | Kanagawa, H.
This study ws carried out to determine the effects of supplementation of the maturation media with insulin on in vitro maturation and fertilization of bovine oocytes. In Experiment 1, cumulus-intact bovine oocytes were cultured in a maturation medium (TCM-199 containing 10% fetal calf serum, 0.02 U/ml follicular stimulating hormone and 1 mu-g/ml estradiol-17beta) with or without insulin supplementation (10 mu-g/ml). The maturation and fertilization rates of oocytes and subsequent embryonic development to the blastocyst stage were not affected by the treatment with insulin in the presence of serum and the hormones during the maturation period. In Experiment 2, to avoid the effects of serum and the hormones, a serum- and hormone-free maturation medium (TCM-199 containing 1 mg/ml polyvinyl alcohol) was used. In the absence of serum and hormones during the maturation period, the maturation rate was not affected by treatment with insulin, but the fertilization rate was improved. In Experiment 3, when denuded oocytes were inseminated together with cumulus cells cultured in serum- and hormone-free maturation medium supplemented with insulin, the fertilization rate was increased. These results demonstrate that the addition of insulin to the serum- and hormone-free maturation medium improves the fertilization rate of bovine oocytes in vitro, and suggest that insulin may stimulate the secretion of sperm capacitating agent(s) from cumulus cells
Show more [+] Less [-]Suspected nutritional myopathy in two captive Bennett's wallabies (Macropus rufogriseus)
1995
Braga, I.S. III (Hokkaido Univ., Sapporo (Japan)) | Tanaka, S. | Ochiai, K. | Itakura, C.
Between January and april, 1992, two captive Bennett's wallabies (Macropus rufogriseus) from a wildlife park in Iwamizawa City, Hokkaido, Japan, were diagnosed as having nutritional myopathy. One wallaby, four-year-old adult male, had mild fresh lesions, confined to the skeletal muscles, with poor cell reaction. The other wallaby, 8-month-old female joey, had marked and extensive lesions with cellular reactions and regenerative muscle fibers in the locomotor muscles. Involvement of other striated muscles such as those of the tongue, diaphragm and heart was mild with minimal cellular reaction. Age susceptibility may account for the difference in the extent of severity of the lesions between these two animals
Show more [+] Less [-]Preliminary efficacy trial of cymelarsan in mice artificially infected with Trypanosoma brucei brucei isolated from a dog in Zambia
1995
Syakalima, M. (Hokkaido Univ., Sapporo (Japan)) | Yasuda, J. | Hashimoto, A.
An efficacy trial of Cymelarsan (R) on a Zambian strain of Trypanosoma brucei brucei was done. Twenty-five male mice were infected intraperitoneally with 10(6) of T. b. brucei isolated from a dog. Five groups of 5 mice were treated with 0 (control), 0.25, 0.5, 1.0 and 2.0 mg/kg cymelarsan, respectively. The target was to achieve aparasitaemia for 30 days post-treatment, euthanising those that remained parasitaemic or relapsed before then. The 0.25 and 0.5 mg/kg groups remained parasitaemic although the parasitaemic levels were reduced. The 1.0 mg/kg group had a proportion of aparasitaemic mice. However, all mice in the 2.0 mg/kg group remained aparasitaemic until day 20 when 2 mice relapsed. These results suggested that more than 2.0 mg/kg was required to eliminate this strain
Show more [+] Less [-]Electrofusion of zona-free mouse embryonic cells in electrolytes and their development in vitro
1995
Elsheikh, A.S. (Hokkaido Univ., Sapporo (Japan)) | Takahashi, Y. | Tanaka, H. | Hishinuma, M. | Kanagawa, H.
The influence of increasing the physical electrofusion parameters, direct current (DC) pulse strength, pulse duration, pulse number, alternating current (AC) voltage and alignment time, in electrolytes on the rates of fusion,degeneration and development of zona-free mouse 2-cell embryos were examined. Furthermore, the effects of physiological saline and mannitol as fusion media and various mouse strains were also evaluated. Dulbecco's phosphate-buffered saline (PBS) supplemented with 10% fetal calf serum was used as the main fusion solution. A significant increase in the rate of fusion (P0.05) was obtained by increasing pulse strength from 30 to 300 V/mm. The embryos fused at the pules strengths of 30 to 70 V/mm had significantly higher development rates to blastocysts compared with those fused at 100 to 300 V/mm (P0.05). There were no significant differences in the rates of fusion, degeneration and d development to blastocysts when the pulse duration was increased from 30 to 90 mu-sec. Although fusion rates were increased (P0.05) by increasing the pulse number up to 4, a significant decrease (P0.05) in development to blastocysts was observed when the pulse number was 5. Application of AC voltage prior to the DC pulse tended to increase the fusion rate (89.2-93.8%), compared with fusion with the DC pulse only (75.0%). Prolongation of alignment time from 5 to 15 sec had no effect on the fusion rate. Under the optimum conditions (2 pulses of DC of 7- V/mm, 70 mu-sec pulse duration and AC of 5 V/mm for 5 sec), no significant difference was obtained in the fusion and development rates in different mouse strains, nor were fusion and development rates significantly different among PBS, physiological saline and mannitol solutions (P0.05)
Show more [+] Less [-]The use of preserved colostrum for rearing replacement dairy calves: calf performance, economics and on-farm practicability in Kenya
1995
Karioki, D.I. (Nairobi Univ. (Kenya). Dept. of Clinical Studies) | Gitau, G.K. | Munyua, S.J.M.