Fifteen and eight mature beagles, without (normal group) and with experimental mitral regurgitation (MR group), respectively, were given 0.02 mg/kg/day digoxin powder for 10 days orally. The optimum time for sample collection after administration of digoxin was observed to be 8-18 hr and 10-22 hr in the normal and MR groups, respectively. In both groups, a stable concentration was reached after 3-5 days of treatment. No differences in plasma level were observed between sexes. The optimum concentration of digoxin was attained at an earlier stage than has been previously reported for both dogs and humans. 相似文献
Over 54,600 ha of table grapes (Vitis vinifera), mainly cvs. ‘Thompson Seedless’, ‘Flame Seedless’ and ‘Redglobe’, are planted in Chile. Almost the entire production is exported to the USA, Europe, Asia, or one of several Latin American countries, which typically requires 15–40 d of maritime transportation. During this period, several physical, physiological, and pathological factors cause table grape deterioration. Because berry size is the main quality factor in international markets, farmers often overuse the growth regulators, gibberellic acid (GA3) and forchlorfenuron (CPPU), in an effort to increase berry size. We examined the effect of preharvest growth regulators on seedless (‘Thompson Seedless’, and ‘Ruby Seedless’) and seeded (‘Redglobe’) table grape cultivars during cold (0 °C) storage plus a shelf life period of 3 d at 20 °C. The overuse of GA3, eight instead of two GA3 applications on Thompson Seedless, and the use of one GA3 application on Redglobe and ‘Ruby Seedless’, increased berry pedicel thickness and lowered cuticle content but induced shatter and predisposed grapes to gray mold caused by Botrytis cinerea. In contrast, CPPU increased berry pedicel thickness and cuticle content but did not increase shatter or gray mold incidence. Clusters that were subjected to overuse of combined GA3 and CPPU were highly sensitive to shatter, had the thickest pedicel, and developed a high gray mold incidence during cold storage. Hairline, a fine cracking developed during cold storage, was induced on ‘Thompson Seedless’ and ‘Ruby Seedless’ by growth regulators, but no hairline occurred on ‘Redglobe’ table grapes. Therefore, berry quality during cold storage is greatly influenced by growth regulator management in the vineyard. 相似文献
On March 20, 2000, a suspected vesicular disease in cattle was reported to the National Veterinary Research and Quarantine Service (NVRQS) of the Republic of Korea. This represented the index case of a foot-and-mouth disease (FMD) outbreak, which spread through several provinces. The Republic of Korea had been free of FMD for 66 years prior to the reintroduction of the virus and had recently suspended imports of pork and pork products from neighboring Japan owing to a reported FMD outbreak in that country. The Korean outbreak was ultimately controlled through the combination of preemptive slaughter, animal movement restrictions, and a strategy of ring vaccination. The purpose of this paper is to review the current FMD situation in Korea in the aftermath of its 2000 epizootic and how it may affect future efforts to eradicate or reduce risk of reintroduction of the disease into Korea. 相似文献
This study was undertaken to quantify the relationships between the rate of ammonia excretion by brine shrimp and dry weight (body size) and food density. Measurements of the rate of ammonia excretion of the brine shrimp were made at 25 C in darkness. Under these conditions, the excretion rate of ammonium-nitrogen can be generalized as a function of body weight and food (Nannochloropsis sp.) density. The relationship between the body weight (W) and excretion rate of ammonium nitrogen (EN) is expressed as EN=α Wγ, where α is the metabolic level. The parameter α is dependent on ration, such that α=αo±αr where αo= metabolic level in starvation and αr= the metabolic level which increased with feeding or changed with the food density. In experiments in which the animal starved, the equation above becomes EN=αoWγ, and the values of α and γ were 0.22 and 0.93, respectively. The rate of ammonium excretion rose from 5.42 × 10?4 to 2.28 × 10?1μg N/animal/h as dry weight measured from 1.57 × 10?3? 1.04 mg dry weight per animal. Next, it is convenient to express αr as αr=αfmax= (1 ? 10?kc), where αfmax is the maximum rate of αf at saturated level of food density, C is the mean cell density, and k is a constant defining the rate of change of the metabolic rate with cell density. Therefore, the rate of ammonia excretion by brine shrimp could be expressed as EN=αo [1 ? a(l ? 10?kC)]Wγ, and a =αfmax/αo. The values of the kinetics parameters obtained from experiments where shrimp were fed were a = 2.3 and k = 0.15×10?7. Consequently, the maximum rate of ammonia excretion at a saturated food density is equivalent to 3.3 times the rate of animals that are not fed. 相似文献
1. One hundred and seven laying hens were hypophysec‐tomised to clarify the relationship between hypophysectomy and the effect of progesterone (P4) on ovulation.
2. Hens were hypophysectomised at 6 intervals from 4.5 to 11.0 h before the expected time of ovulation. Ovulation occurred in the hens operated on from 4.5 to 7.3 h, but did not take place in birds operated on from 9.2 to 9.8 h before the expected time of ovulation.
3. When a single dose of P4 (2 mg/hen) was injected iv immediately after the removal of the anterior pituitary from 7.5 to 9.8 h before the expected time of ovulation, ovulation was induced. However, the percentage of hens responding decreased in proportion to the lapse of time between the hypophysectomy and the expected time of ovulation. No ovulation was induced in hens which were hypophysectomized and given P4 10.2 to 11.0 h before the expected time of ovulation.
4. It is suggested that ovulation is induced by P4 alone possibly in the absence of preovulatory gonadotrophins and that P4 acts directly on the ovary to induce follicle rupture. 相似文献