Lack of mutagenicity of fasciolicides

Six fasciolicides, bithionol, bromofenofos, DS-6, nitroxynil, oxyclozanide and tribromsalan, were tested for mutagenicity in theSalmonella reverse mutation test usingS.typhimurium tester strains TA100, TA98, TA153, TA1537 and TA1538 and the micronucleus test in mice. None of the fasciolicides increased the number of revertant colonies in any tester strain in the presence and absence of S9 mix, nor did they induce a significant increase of the micronuclei in erythrocytes. Taking the high correlation between mutagenicity and carcinogenicity into consideration, these results suggest that the fasciolicides tested in this investigation are devoid of carcinogenic action.     

Comparison of the activity of some fasciolicides against immature liver fluke in calves

The anthelmintic activities of nitroxynil, closantel and rafoxanide were tested in cattle against six- and eight-week-old infections of Fasciola hepatica. Administered by subcutaneous injection, nitroxynil and rafoxanide at dose rates of 10 and 3 mg/kg bodyweight respectively were 88.5 and 36.1 per cent effective in eliminating a six-week-old infection of F hepatica and 85.8 and 60.4 per cent effective against an eight-week-old infection. Closantel administered by intramuscular injection at a dose rate of 2.5 mg/kg bodyweight was 60.0 per cent effective against an eight-week-old F hepatica infection.     

Field trial on comparative efficacy of four fasciolicides against natural liver fluke infection in cattle

A controlled trial was conducted to evaluate the current efficacy of albendazole (ABZ), rafoxanide (RFX), triclabendazole (TRC) or clorsulon (CLS) against Fasciola hepatica in naturally infected cattle. This trial was conducted in Turkey during the spring, the time of year when liver fluke infection is endemic. Fifty crossbred cattle were selected for inclusion in the trial based on finding eggs of F. hepatica in the feces. The cattle were weighed and randomly allotted into five groups of 10 cattle and treatments were as follows: Group 1 served as non-treated control (CONT), Group 2 was treated orally with ABZ at 12 mg/kg, Group 3 was treated orally with RFX at 10 mg/kg, Group 4 received TRC orally at 12 mg/kg and Group 5 received CLS administered subcutaneously (s.c.) at 2 mg/kg. On day 0 (inclusion day), individual fecal samples were collected on days 0 (inclusion day), 7, 14, 28 and 56, after treatment. The drug efficacy was assessed as a percentage of the egg or fluke reduction and body weight gain relative to the untreated control. The results in the study showed a mean reduction of egg counts by 66.7%, 68.2%, 78% and 84.2% in Groups 2-5, respectively. In conclusion, our results indicate that CLS is a highly effective compound for the treatment of F. hepatica in cattle under these field conditions.     

产后康复宁的致突变、致畸试验研究

采用小白鼠骨髓多染红细胞微核试验和小白鼠致畸试验等方法,对产后康复宁的致突变性和致畸性进行了观察.小白鼠骨髓多染红细胞微核实验结果PCE/NCE为1.0085/1.2567.结论:产后康复宁无致突变作用.     

橘皮素乙酰酯致突变性研究

橘皮素乙酰酯是搐皮素结构改造后获得的衍生物，是一种新型杀螨药物，通过Ames试验、小鼠骨髓细胞微核试验、精子畸形试验，考察了橘皮素乙酰酯的致突变性。结果：在活化与非活化条件下，诱发TA97、TA98、TAl00和TAl02的回变菌落数与自发回变菌落数相近，无剂量反应关系；各试验组微核率(2．20‰～2．40‰)与阴性(2．00‰)和溶剂对照组(1．88‰)相近；精子畸形率(2．48％～2．72％)与阴性(2．36％)和溶剂对照组(2．06％)比较也无显著差异。表明橘皮素乙酰酯无致突变性．     

牛维生素A缺乏症及防治

1　病因牛吃入含维生素Ａ原 (胡萝卜素 )的青草、胡萝卜、南瓜、玉米等之后 ,将胡萝卜素在肠黏膜细胞转换成维生素Ａ。维生素Ａ的大部分和少量的胡萝卜素贮存于肝脏内 ,其余部分维生素Ａ和胡萝卜素则贮存沉积在脂肪中 ,需要时被利用。一般从春天到初夏在嫩青草中 ,无论是禾本科还是豆科的绿色部分中都含有大量的胡萝卜素。因此 ,在日粮中缺乏优质干草、青贮牧草和幼嫩植物 ,也就缺乏了胡萝卜素的来源。另外 ,如果母牛不缺乏维生素Ａ ,其初乳中也含有大量维生素Ａ。所以让新生犊牛吃足初乳 ,维生素Ａ就会被贮存于犊牛的肝脏中 ,其后不易出现…     

Lack of consensus on consensual response

The pupillary light reflex (PLR) is a routinely utilized clinical test to quickly assess integrity of subcortical light perception pathways in patients. While interpretation is simple for ophthalmologists, interestingly discrepancy occurs in annotation of the test results, especially for the consensual response. An email survey sent to diplomates of either the American or European Colleges of Veterinary Ophthalmologists (ACVO and ECVO, respectively), requesting use of a ‘direct/consensual’ annotation convention, showed 58% of respondents preferred one convention while 39% preferred a different convention. The majority preferred convention was different between ACVO and ECVO respondents. Standardization of PLR annotation convention across specialists is recommended for clarity in medical record keeping and communication among colleagues.     

Lack of arrhythmogenicity of aminophylline in dogs

This study was designed to determine if doses of aminophylline up to 10 mg/kg given i.v. would produce ventricular arrhythmias in seven healthy dogs anaesthetized with fentanyl-dropelidol-pentobarbital. Arrhythmias were sought by inspection of ECGs before and after attempts at provoking them with 5 pg/ kg boluses of epinephrine given i.v., or by programmed electrical stimulation. After cumulative doses of 10 nig aminophylline/kg body weight, producing an estimated plasma concentration of greater than 30 pginil, no ventricular ectopia other than escape depolarizations were observed. We were unable t o document
an arrhythmogenic effect of aminophylline when given rapidly by the i.v. route. I t is possible that the anaesthetic regimen reduced the arrhythmogenic property of aminophylline, or that arrhythmias might be produced in either obese or ill dogs; but it is unlikely that chronic administration of aminophylline would be more arrhythmogenic.     

Lack of formyl-methionyl-leucyl-phenylalanine receptors on porcine neutrophils

The response of blood neutrophils to the chemotactic peptide formyl-methyl-leucyl-phenylalanine varies among species. Our results indicate that this peptide does not activate the respiratory burst of porcine neutrophils. Specifically, concentrations less than or equal to 10(-6) M did not cause production of either superoxide or hydrogen peroxide. Studies designed to delineate the biochemical deficit responsible for these results indicated that these cells do not express specific chemotactic peptide receptors on the external surface of the plasma membrane. Although these data do not rule out the possibility that internal stores of chemotactic peptide receptor exist, attempts to induce expression of the receptor by priming the cells with either lipopolysaccharide or calcium ionophore were unsuccessful.     

豆类丝核菌次级代谢产物的急性毒性与致突变性试验

通过经口急性毒性试验、小鼠骨髓微核试验和精子畸形试验对豆类丝核菌次级代谢产物的急性毒性和致突变性进行了研究.结果表明,以该代谢产物中苦马豆素的量计算,小鼠经口急性毒性试验的LD50为226.46mg/kg,LD50的95%可信限为158.49～323.59mg/kg,是治疗肿瘤剂量的14～84倍,属于实际低毒级药物.微核试验和精子畸形试验的各试验组与阴性对照组比较差异均不显著(P＞0.05),说明豆类丝核菌次级代谢产物无明显致突变性;各试验组之间比较差异均不显著(P＞0.05),说明微核的形成和精子畸形的形成与受试物无量效关系.结论:豆类丝核菌次级代谢产物是一种较安全的抗肿瘤药物.     

Lack of Evidence of Pregnancy-Induced Alloantibodies in Dogs

Background: It is controversial whether or not pregnant bitches become sensitized to red blood cell (RBC) antigens.
Hypothesis: Bitches do not develop alloantibodies to RBC antigens during gestation and can be used safely as blood donors.
Animals: The study group included 35 healthy female dogs with a prior history of 1 (n = 12), 2 (n = 14), or ≥ 3 (n = 9) pregnancies. The control group consisted of 15 healthy female dogs without any history of pregnancy.
Methods: All dogs were blood typed for dog erythrocyte antigens (DEA) 1.1, 1.2, 3, 4, 5, and 7 using ethylenediaminetetraacetic acid blood samples and polyclonal antisera. Antibody screening was performed with serum and canine RBC panels of known blood type. An autocontrol and direct antiglobulin test were performed to rule out the presence of autoantibodies.
Results: The only alloantibodies identified were those against DEA 7 and the prevalence of anti-DEA 7 alloantibodies was similar in dogs with known history of pregnancy (11.4%) and in the control group (13.3%).
Conclusions and Clinical Importance: These results confirm previous studies and clinical transfusion medicine experience. Naturally occurring anti-DEA 7 alloantibodies have been reported but their clinical relevance has not been shown. Pregnancy does not appear to sensitize dogs to RBC antigens. Consequently, dogs with prior history of pregnancy can be used safely as blood donors. Conversely, no additional pretransfusion compatibility studies would be required should these dogs themselves need to be transfused.