Altered disposition of propylthiouracil in cats with hyperthyroidism

The oral and intravenous disposition of the anti-thyroid drug propylthiouracil (PTU) was determined in six clinically healthy cats and four cats with naturally occurring hyperthyroidism. Compared with the normal cats, the mean plasma elimination half-life of PTU was significantly (P less than 0.001) shorter in the hyperthyroid cats (77.5 +/- 5.8 minutes compared with 125.5 +/- 3.7 minutes) and the total body clearance of PTU was significantly (P less than 0.05) more rapid in the cats with hyperthyroidism (5.1 +/- 0.8 ml kg-1 min-1 compared with 2.7 +/- 0.2 ml kg-1 min-1). Following oral administration, both the bioavailability (59.7 +/- 4.9 per cent compared with 73.3 +/- 3.7 per cent) and peak plasma concentrations (14.5 +/- 1.6 micrograms ml-1 compared with 18.9 +/- 0.9 micrograms ml-1) of PTU were significantly (P less than 0.05) lower in the hyperthyroid cats than in the control cats. No difference was noted, however, between the apparent volume of distribution for PTU in the two groups of cats. Overall, results of this study indicate that the oral bioavailability of PTU is decreased and PTU disposition is accelerated in cats with hyperthyroidism.     

Prolonged gestation in a Holstein cow: adenohypophyseal aplasia and skeletal pathology in the offspring

A Holstein fetus was delivered by Caesarean section at a gestational age of 441 days. The pituitary pars distalis was aplastic and the adrenal and thyroid glands were severely hypoplastic. Arrested or retarded cartilage cell maturation resulted in absence or minimal development of epiphyseal ossification centers, delayed ossification of carpal bones, and arrest of longitudinal growth of bones. The pathophysiology of prolonged gestation and of skeletal pathology is discussed.     

ACUTE TOXICITY OF PROPANIL,ORDRAM AND FURADAN TO CRAWFISH (Procambarus clarkii) WHEN CHEMICALS WERE COMBINED AND USED ALONE1

In laboratory studies, acute toxicity tests (96-hour) showed strong main effect on crawfish when Propanil, Ordram, and Furadan were combined; this combination was the most toxic treatment to crawfish. Furthermore, a strong interaction among the three suggests a non-additive response. Ordram alone was the least toxic pesticide. Additive effect was observed when Furadan was combined with Ordram or Propanil, but antagonism was detected in the combination of Propanil with Ordram. Concentrations higher than the recommended rate for use at normal conditions had a significant (P<0.05) lethal effect on crawfish. Soil moderated the toxicity of some pesticides and their combinations.     

Immunoregulation of fish nonspecific cytotoxic cell activity by retinolacetate but not poly I:CImmunomodulation de l'activité cytotoxique non spécifique de cellules de poisson par le rétinolacétate mais non par le poly I:C

Nonspecific cytotoxic cells (NCC) from fish (Ictalurus punctatus) were treated with different concentrations of retinolacetate and poly I:C. Both in vitro and in vivo experiments were conducted. Retinolacetate significantly increased NCC activity against chromium-51 labeled human B-cell lymphoma target cells (NC-37). Preincubation (treatment prior to adding the labeled target cells) of NCC for 4 to 8 h in 10^?3 to 10^?12 M concentration of retinolacetate produced significant increases in NCC activity compared to treatment during the killing assay only. Similar experiments with different concentrations of poly I:C had no NCC augmenting effects when tested by adding poly I:C either during preincubation periods or during the cytotoxicity assay. Retinolacetate probably produces positive modulation of cytotoxicity by increasing the killing effectiveness of individual NCC, rather than recruiting larger numbers of cytolytic cells. In vivo studies were also conducted by injecting catfish (i.p.) with 1 ×, 3 × and 5 × the daily recommended vitamin A dosages and determining NCC activity after 24, 48 and 72 h treatment. The 1 × dose significantly increased NCC activity at 72 h. This increase was not transient because NCC activity after 33–37 days' treatment was significantly higher than controls in the 1 ×, 2 × and 3 × groups. Intraperitoneal injections of fish with poly I:C produced no significant increases in NCC activity at 24 or 72 h post-inoculation.     

Recurring hemolytic anemia, babesiasis, and influenza A viruses in a yak at low altitude in Nepal.

Episodes of hemolysis and leukocytosis which were associated with Babesia bigemina followed each of 3 challenge exposures to influenza A viruses. It is possible that viral infection altered the immunologic host-parasite equilibrium. Acute thrombocytopenia and rouleaux formation were also observed. Death, attributed to liver flukes, occurred 168 days after the yak was transferred from high to low altitude. A 2nd yak died of foot-and-mouth disease, thus supporting the Nepali belief that yaks will not survive at the lower altitudes of Kathmandu.     

The role of behavior in insecticide resistance

Although behavioral resistance remains enigmatic, an examination of the literature firmly supports the existence of behavioral resistance in both the presence and absence of the better understood and accepted physiological and biochemical mechanisms. Studies of pyrethroid resistance in the horn fly and the tobacco budworm have identified several resistance mechanisms, including behavioral adaptations, in addition to target-site insensitivity and enhanced detoxification. The coexistence of physiological and behavioral responses neither precludes a common mechanism nor requires one. Even if a common mechanism such as knockdown resistance or enhanced detoxification is involved, this does not negate the survival benefit of either avoiding the toxicant or reducing movement to avoid exposure. Thus, behavioral resistance may be much more ubiquitous and important than previous interpretation of the literature suggests.     

Insecticide resistance management: Relationship to integrated pest management

Insecticide resistance management (IRM) is a component of integrated pest management (IPM) that has the goal of forestalling resistance development to all insecticides. Since the advent of the organochlorine insecticides in the 1940s, an average of about one class of insecticide has been lost every 10 years because of resistance. Effective insecticides are necessary for optimum IPM and are too important and too expensive a resource to be lost so rapidly. By adhering to the principles of IPM and utilizing other IPM components such as biological and cultural control, IRM has the potential of conserving the susceptibility of pests to insecticides. Although initial attempts of IRM appear to be successful, it is imperative that research to undergird IRM be greatly accelerated.     

科学构建国家兽医药品公共信息平台促进产业发展

文章探讨了兽医药品信息对政府、企业、消费者以及产业发展的重要意义，国家如何科学地构建行业专业的信息平台，实施兽医药品产业、政务、公共信息数字化网络化，通过信息化建设推进产业发展。