A Survey of Veterinarians’ Attitudes toward Euthanasia of Companion Animals in Japan

This study investigated veterinarians’ attitudes toward euthanasia of companion animals in Japan. A nationwide survey was conducted with 932 veterinarians in small animal practices. It examined the number of times they administered euthanasia, their moral criteria for choosing euthanasia for animals, and their behavioral criteria for suggesting euthanasia to owners. According to the data analyses, on average the veterinarians administered euthanasia 2.48 times a year. For many veterinarians, two conditions were necessary to justify euthanasia for animals: “the animals are incurable and suffering” and “the owners request to euthanize the animals.” In the absence of either condition, the veterinarians were inclined to disapprove of choosing euthanasia. If the owners requested further treatment, 67% showed clear disapproval of choosing euthanasia for animals with serious medical conditions. Meanwhile, more than 76% showed clear disapproval of euthanizing healthy animals when the owners requested it. These results indicate that the owners’ request takes precedence over the animals’ condition for suffering animals, but not for healthy animals. For animals with serious medical conditions, 56% of the veterinarians answered that they would or might suggest euthanasia to the owners even though the owners requested further treatment. In this situation, for some veterinarians, the animals’ condition rather than the owners’ request might become a determinant in suggesting euthanasia to owners, even if their moral judgments were against choosing euthanasia for the animals. A decrease in the owners’ or the animals’ quality of life and the owners’ inability to pay were not primary factors in choosing or suggesting euthanasia. Having an experience of euthanizing their own animals was a key factor for the veterinarians which increased not only the number of times they administered euthanasia but also the degree of their moral approval of choosing euthanasia and their behavioral willingness to suggest it to owners.     

Metabolism of apoprotein B in selectively bred baboons with low and high levels of low density lipoproteins

Very low density lipoprotein (VLDL) and low density lipoprotein (LDL) apoprotein (apo)-B turnover rates were measured simultaneously by injecting 131I-labeled VLDL and 125I-labeled LDL into fasting baboons (Papio sp.) selectively bred for high serum cholesterol levels and having either low or high LDL levels. The radioactivities in VLDL, intermediate density lipoprotein (IDL), LDL apoB, and urine were measured at intervals between 5 min and 6 days. Kinetic parameters for apoB were calculated in each baboon fed a chow diet or a high cholesterol, high fat diet (HCHF). VLDL apoB residence times were similar in the two groups of animals fed chow; they were increased by HCHF feeding in high LDL animals, but not in low LDL animals. Production rates of VLDL apoB were decreased by the HCHF diet in both high and low LDL animals. Most of the radioactivity from VLDL apoB was transferred to IDL. However, a greater proportion of radioactivity was removed directly from IDL apoB in low LDL animals than in high LDL animals, and only about one-third appeared in LDL. In high LDL animals, a greater proportion of this radioactivity was converted to LDL (61.4 +/- 7.2% in chow-fed animals and 49.2 +/- 10.9% in animals fed the HCHF diet; mean +/- SEM, n = 5). Production rates for LDL apoB were higher in high LDL animals than those in low LDL animals on both diets. The HCHF diet increased residence times of LDL apoB without changing production rates in both groups. VLDL apoB production was not sufficient to account for LDL apoB production in high LDL animals, a finding that suggested that a large amount of LDL apoB was derived from a source other than VLDL apoB in these animals.     

哨兵动物概述

哨兵动物在我国还未作为一个＂工具＂用于实验动物微生物检测工作,但随着实验动物种类和特殊动物的日益增加,现有方法已经不能满足检测需要。探讨哨兵动物的应用,采用国外先进方法,对提高我国实验动物质量显得非常重要。本文对哨兵动物的概念、使用方法和设置做一概述。     

无菌动物及其在微生物与宿主互作机制研究中的应用

无菌动物是指通过现代技术手段在其体内外的任何部位均检测不出细菌、真菌、放线菌、支原体、衣原体、螺旋体、立克次氏体、病毒、原生动物和寄生虫的动物。无菌动物因其不携带任何微生物,可转化为携带特定微生物的动物,同时因其免疫系统处于休眠状态,对微生物感染异常敏感,可建立多种悉生动物模型,用于特定微生物感染实验和致病机制研究。此外,无菌动物作为关键工具,是研究菌群与疾病关系的核心,在微生物与宿主健康、疾病和感染机制研究过程中,起着不可替代的作用。本文将对无菌动物及其在微生物与宿主互作机制研究中的应用进行简要综述。     

Oxidative Stress in Caenorhabditis elegans: Protective Effects of Spartin

Troyer syndrome is caused by a mutation in the SPG20 gene, which results in complete loss of expression of the protein spartin. We generated a genetic model of Troyer syndrome in worms to explore the locomotor consequences of a null mutation of the Caenorhabditis elegans SPG20 orthologue, F57B10.9, also known as spg-20. Spg-20 mutants showed decreased length, crawling speed, and thrashing frequency, and had a shorter lifespan than wild-type animals. These results suggest an age-dependent decline in motor function in mutant animals. The drug paraquat was used to induce oxidative stress for 4 days in the animals. We measured survival rate and examined locomotion by measuring crawling speed and thrashing frequency. After 4 days of paraquat exposure, 77% of wild-type animals survived, but only 38% of spg-20 mutant animals survived. Conversely, animals overexpressing spg-20 had a survival rate of 95%. We also tested lifespan after a 1 hour exposure to sodium azide. After a 24 hour recovery period, 87% of wild type animals survived, 57% of spg-20 mutant animals survived, and 82% of animals overexpressing spg-20 survived. In the behavioral assays, spg-20 mutant animals showed a significant decrease in both crawling speed and thrashing frequency compared with wild-type animals. Importantly, the locomotor phenotype for both crawling and thrashing was rescued in animals overexpressing spg-20. The animals overexpressing spg-20 had crawling speeds and thrashing frequencies similar to those of wild-type animals. These data suggest that the protein F57B10.9/SPG-20 might have a protective role against oxidative stress.     

H22腹水型肝癌荷瘤小鼠耐受性的性别差异

目的:观察性别对小鼠H22腹水型肝癌生长情况的影响,研究不同性别动物对肝癌耐受性的差异。方法:取30只8周龄昆明鼠,雌雄各半,随机分为四组,实验组每组10只,对照组每组5只,腹腔接种小鼠H22肝癌细胞,建立小鼠H22腹水型肝癌模型。每天测量小鼠体重并记录生存时间,直至实验组小鼠全部死亡,比较性别因素对小鼠H22腹水型肝癌的生存期是否存在差异。结果:小鼠接种瘤细胞后,逐渐产生腹水,体重增加。雌性小鼠的体重增加比雄性小鼠显著,P=0.049。雄性小鼠生存后期体重出现下降,呈明显恶液质状态。雌性小鼠的体重、腹水增加虽然较雄性动物明显,但生存期却并不少于雄性鼠,反而比雄性小鼠略长,P=0.1567。结论:性别对小鼠H22腹水型肝癌的生长有一定的差异,雌性小鼠的耐受性优于雄性小鼠。     

Prevention of the formation of alcoholic motivation in rats using zinc sulfate

The experiments carried out on albino male rats have shown a decreased zinc content in the brain of active animals selected under conditions of forced swimming test, as compared to passive animals. 10-day intraperitoneal injection of biotic zinc sulfate dose (50 micrograms/kg) resulted in the prevention of alcohol motivation in active animals. There was no such effect in passive animals. The differences between basic mechanisms of alcohol motivation in different groups of animals are suggested.     

A Possible Neurochemical Basis of the Central Stimulatory Effects of pp'DDT

Abstract: The striatal neurochemical changes induced by pp'DDT (600 mg/kg) in mice were: an increase in the concentration of free ammonia, a decrease in the level of GABA and a reduction in the level of acetylcholine. These changes were maximal 5 h after treatment with pp'DDT, when the animals developed 'severe' convulsions. The convulsions and striatal neurochemical changes were modified to different degrees by barbiturates. Phenobarbitone protected all the animals from pp'DDT-induced convulsions. The levels of striatal acetylcholine and GABA in these animals were within normal limits. Prominal reduced the severity of convulsions in pp'DDT-treated animals. The levels of striatal acetylcholine and GABA were significantly lower than control values in these animals. Primidone neither modified the convulsions nor the striatal neurochemical changes in pp'DDT-treated animals. The increase in the concentration of free ammonia, in pp'DDT-treated animals, was not modified by barbiturates. Aminooxyacetic acid raised the GABA level above normal and abolished the convulsions in pp'DDT-treated animals; the level of acetylcholine was within normal limits in these animals. Hydroxylamine produced a similar but less marked effect. Pyridoxine had no effect on convulsions or striatal neurochemical changes induced by pp'DDT. The increase in the concentration of free ammonia in pp'DDT-treated animals was not modified by these agents. It is likely that pp'DDT produced stimulatory effects by increasing the concentration of free ammonia which may be involved in reducing the level of GABA, while changes in the level of acetylcholine may be an effect of pp'DDT-induced convulsions.     

Characteristics of the late A-response of vasoconstrictor neurons in cats decerebrated at different brain stem levels]

In cats decerebrated at the level of the rostral border of the midbrain (the mesencephalic animals) and in those decerebrated at different pontine levels, including the ponto-bulbar junction level, and the most rostral parts of the medulla oblongata (the "pontine" animals), or more caudal parts (the bulbar animals), single stimulus of the tibial nerve A-fibres elicited a late response in the renal nerve consisting of excitatory and inhibitory components. The excitatory component was relatively small or absent in 53% of the "pontine" animals, in 42% of the mesencephalic animals, and in 18% of the bulbar animals. The "pontine" animals had the most active and most excitable system of the inhibitory component generation. However, the signs of a comparatively more powerful inhibitory component of the A-afferent action of the vasoconstrictor neurones in the "pontine" animals were not as constant as to explain completely the transition of somatic A-afferent hypertensive reflexes into the hypotensive ones, occurring in separating the ponto-bulbar structure and the rostral parts of the medulla oblongata from the mesencephalon.     

Validation of an automatic system (DoubleCage) for detecting the location of animals during preference tests

Preference tests have often been performed for collecting information about animals' acceptance of environmental refinement objects. In numerous published studies animals were individually tested during preference experiments, as it is difficult to observe group-housed animals with an automatic system. Thus, videotaping is still the most favoured method for observing preferences of socially-housed animals. To reduce the observation workload and to be able to carry out preference testing of socially-housed animals, an automatic recording system (DoubleCage) was developed for determining the location of group-housed animals in a preference test set-up. This system is able to distinguish the transition of individual animals between two cages and to record up to 16 animals at the same time (four animals per cage). The present study evaluated the reliability of the DoubleCage system. The data recorded by the DoubleCage program and the data obtained by human observation were compared. The measurements of the DoubleCage system and manual observation of the videotapes are comparable and significantly correlated (P < 0.0001) with good agreement. Using the DoubleCage system enables precise and reliable recording of the preferences of group-housed animals and a considerable reduction of animal observation time.     

Morphofunctional study of the statocyst of the cuban crayfishprocambarus cubensis

After replacing sand, a natural component of the endogenous otolithic apparatus of the Cuban crayfishProcamabrus cubensis by particles of reducible iron and subsequent exposure of the animals to a constant magnetic field, the following changes were noted in their behavior: during the first 24 h the motor activity of the animals increased and was accompanied by frequent strong beats of antennulae on water; animals tried to go away from the magnet attached to the aquarium wall and to hide in a shelter; by the day 10–12, there appeared signs of adaptation to the action of magnet; the animals spent most time near the wall with the magnet and were clinging close to it. If the magnet was moved the animals not only slipped to their side but also rotated around their longitudinal axis. The eyestalks also started moving. After molt and repeated introduction of reduced iron particles into the statocysts, a negative reaction to magnet was practically absent, and the crayfish preferred staying near the magnet. Study of structural organization of the statocysts under a scanning electron microscope showed that the iron particles in the otolithic apparatus of the crayfish are covered with a thinner layer of glycocalyx as compared to control animals whose otolithic apparatus is composed of sand grains. Besides, the otolithic apparatus of the experimental animals is a loose formation, unlike the dense glycocalyx rich in conglomerate in control animals.     

Religiosity and Support for Killing Animals: Evidence of a Curvilinear Relationship

ABSTRACT

Prior research shows that the correlation between religiosity and support for animal rights can be positive, negative, or zero. We hypothesized that this relationship may actually be curvilinear, where a moderate degree of religiosity may reduce support for killing animals (compared with non-religiosity or atheism), but a very high degree of religiosity (e.g., fundamentalism) might increase support for killing animals. We tested this hypothesis in a large sample of American undergraduate students, using a correlational study design with self-report measures of religiosity and of support for killing animals in different domains. The results indicated that, in support of our hypothesis, the relationship between religiosity and support for killing animals is curvilinear, as moderate levels of religiosity were related to less support for killing animals. People who were either not religious at all or very religious were the ones who most supported the killing of animals. Belief in God in itself was related to less support for killing animals. We then replicated the curvilinear relationship between religiosity and support for killing animals using data from four experiments from a previously published article on support for killing animals. We briefly consider possible explanations for these findings, the limitations of the study, and propose directions for future research. Overall, we believe that this study helps clarify the complex relationship between religiosity and support for killing animals, and advances the scientific understanding of the psychological forces that motivate people to support or object to the killing of animals.     

Alteration of the apparent Ki of carnitine palmitoyltransferase for malonyl-CoA by the diabetic state and reversal by insulin

The effects of streptozotocin-induced diabetes and the subsequent treatment of diabetic animals with insulin were studied using a dose of streptozotocin that produces highly ketotic animals 48 h after injection. Carnitine palmitoyltransferase of diabetic animals had apparent Ki values for malonyl-CoA that were approximately 10 times greater than control animals, indicating a greatly decreased affinity for malonyl-CoA in the diabetic state. Subsequent treatment of diabetic animals with insulin for 5 days produced non-ketotic animals with normal blood glucose, and the affinity of carnitine palmitoyltransferase for malonyl-CoA was increased to the control level. Treatment of other groups of ketotic diabetic animals with insulin produced substantial changes in the carnitine palmitoyltransferase apparent Ki value for malonyl-CoA within 4 h. These results suggest that insulin modulates the ketotic state, at least in part, by increasing the affinity of carnitine palmitoyltransferase for malonyl-CoA to bring about inhibition of fatty acid oxidation and ketogenesis.     

Effect of training for loads in the ventrodorsal direction on the blood vessels of the sympathetic trunk of the rabbit brain]

Thirty six rabbits underwent special training to get a state of being trained. In a centrifuge with a 1 m radius 18 animals got ventro-dorsal gravitation stress according to schedule N 1 (with limberung-up) and 18 animals according to schedule N 2 got gravitation stress without limbering-up. After training the animals had a 2, 3 and 4-week rest. Then a part of animals was killed and served as control and the others were subjected to a single exposure to stress of the same direction (10 units for 40 min). This stress was unendurable for untrained animals. By means of injection, clearing, measuring the vessels and histologically it was shown that the trained state was reached according to schedule N 2 and retained for 3 weeks. It was also confirmed by survival of animals and the state of the vessels of the sympathetic trunk. Training according to the 1st schedule resulted in cumulation.     

Application of Cortexin for correcting the consequences of hypoxic-ischemic damage in the brain of infant rats

To verify if the peptide preparation Cortexin can be used to correct pathological processes in the CNS during perinatal ontogenesis, a set of physiological parameters (EMG, ECG, respiration, vagosympathetic balance) were recorded and analyzed in a rat perinatal hypoxic-ischemic brain damage (PHIBD) model and control infant rats. In experimental 7-day-old animals, PHIBD was modeled under inhalation ether anesthesia by ligation of the left common carotid artery and subsequent exposure to a gas mixture of 8% oxygen and 92% nitrogen. 1 h after exposure, animals were first injected intraperitoneally with cortexin (1 mg/kg); the preparation was then injected at a daily basis for 10 days. Both control animals and those after surgery but non-treated were injected with physiological solution. After 10 and 30 days after surgery, animals exhibited a delayed body weight gain versus control and significant differences in EMG intensity and spectral structure. Cortexin treatment induced on day 10 a transient improvement in EMG spectral structure but not amplitude; by day 30, the positive effect of cortexin was no longer observed. The respiration rate both in treated and non-treated animals was higher than in control. No significant changes in the heart rate were revealed in animals with PHIBD, but non-treated animals exhibited on day 30 a tendency towards its decrease. The heart rate variability (HRV) analysis showed that 10 days after trauma both non-treated and cortexin-treated animals exhibited a statistically significant shift in the vagosympathetic balance towards a parasympathetic prevalence. On day 30, cortexin treatment yields positive effects, while in non-treated animals the vagosympathetic balance shifts towards a humoral-metabolic and sympathetic prevalence. Cortexin injection to intact rats leads to significant disturbances in the vagosympathetic balance, cardiac and, to a lesser extent, respiratory rhythms, and can cause stable disturbances in activity of the somatic and vegetative nervous systems.     

Involvement of prostaglandins in the immune alterations caused by the exposure of mice to ultraviolet radiation

Our study was designed to analyze the possible involvement of prostaglandins in the mechanisms responsible for the depressions in contact hypersensitivity (CH) responsiveness observed in UVR-exposed animals. Low-dose UVR-exposed animals were found to exhibit a depressed capacity to elicit CH responses after hapten application to irradiated (devoid of Langerhans cells) or UVR-protected (normal Langerhans cells) dorsal skin surfaces. Normal responsiveness was observed in low-dose UVR-exposed animals sensitized through unirradiated ventral skin surfaces. Indomethacin treatment of low-dose UVR-exposed animals (to inhibit prostaglandin synthesis in vivo) caused a retention in the capacity to respond normally to CH induction to haptens applied to the nonirradiated, but not to irradiated, dorsal skin surfaces. High-dose UVR-exposed animals, which normally exhibit a depression in responsiveness to hapten sensitization, retained a normal capacity to elicit CH responses if treated with the drug indomethacin. These findings implicate prostaglandins in the pathogenesis of the immunologic hyporesponsiveness, observed in low- and high-dose UVR-exposed animals. Our studies also determined that under all experimental conditions where animals were contact sensitized through nonirradiated skin sites, CH-effector cells could be found in the draining lymph nodes. No CH-effector cells were observed in the lymph nodes of mice that were contact sensitized directly through irradiated skin sites. It was also found that the spleens of both UVR-exposed and normal animals contained adoptively transferrable suppressor cells subsequent to hapten application. This demonstration of CH-effector and CH-suppressor cells in both normal and UVR-exposed animals did not directly relate to the potential of the donor animals to elicit a CH response.     

Morphofunctional study of the statocyst of the Cuban crayfish Procambarus cubensis

After replacing sand, a natural component of the endogenous otolithic apparatus of the Cuban crayfishProcamabrus cubensis by particles of reducible iron and subsequent exposure of the animals to a constant magnetic field, the following changes were noted in their behavior: during the first 24 h the motor activity of the animals increased and was accompanied by frequent strong beats of antennulae on water; animals tried to go away from the magnet attached to the aquarium wall and to hide in a shelter; by the day 10—12, there appeared signs of adaptation to the action of magnet; the animals spent most time near the wall with the magnet and were clinging close to it. If the magnet was moved the animals not only slipped to their side but also rotated around their longitudinal axis. The eyestalks also started moving. After molt and repeated introduction of reduced iron particles into the statocysts, a negative reaction to magnet was practically absent, and the crayfish preferred staying near the magnet. Study of structural organization of the statocysts under a scanning electron microscope showed that the iron particles in the otolithic apparatus of the crayfish are covered with a thinner layer of glycocalyx as compared to control animals whose otolithic apparatus is composed of sand grains. Besides, the otolithic apparatus of the experimental animals is a loose formation, unlike the dense glycocalyx rich in conglomerate in control animals.     

Effects of neonatal thymic exposure to high doses of X-irradiation.

The thymic region of neonatal Swiss mice was exposed to doses varying from 1000 R to 2000 R of X-irradiation. The animals did not show any signs of wasting syndrome up to 6 months after irradiation. At this time hyperplasia of the thymus with an associated lymphocytosis was evident in irradiated animals. Antibody production to sheep red blood cells (SRBC) was not affected. However, at 12 months post-irradiation the animals showed signs of wasting disease with a progressive increase in their numbers at 18 and 24 months of age. The percentage incidence of animals with wasting disease was dose dependent. At this stage in the majority of the animals with the disease the thymus showed varying degrees of atrophy along with splenomegaly. There were no significant differences in the number of lymphocytes but the number of granulocytes showed a substantial increase. This was more evident in animals exposed to 2000 R to the thymic region. Though one observed a lowered ability to form antibodies to bovine serum albumin (BSA) with advancing age, the thymic irradiation did not affect the immune response to BSA even in animals manifesting wasting disease. An interesting observation has been the development of a severe loss of muscle power and tone in the hind limbs in a large majority of animals.     

Insulin stimulation of heart glycogen synthase D phosphatase (protein phosphatase).

Insulin rapidly produced an increase in per cent of total heart glycogen synthase in the I form in fed rats. In fasted rats the response was diminished and delayed. In diabetic animals there was no response over the 15-min time period studied. Since synthase phosphatase activity is necessary for synthase D to I conversion, the phosphatase activity was determined in extracts from these groups of animals. In the fasted and diabetic rats phosphatase activity was less than one-half of that in fed animals. Administration of insulin to fasting animals increased synthase phosphatase activity to a level approaching that of fed animals by 15 min. In diabetic animals insulin also stimulated an increase in synthase phosphatase activity but 30 min were required for full activation. Insulin had no effect in normal fed animals. Insulin activation of synthase phosphatase activity in heart extracts from fasted animals was still present after Sephadex G-25 chromatography and ammonium sulfate precipitation. Thus insulin had induced a stable modification of the phosphatase itself or of its substrate synthase D rendering the latter a more favorable substrate for the reaction. A difference in sensitivity of the reaction to glycogen inhibition was present between fed and fasted animals. Increasing concentrations of glycogen had only a slight inhibitory effect in extracts from fed animals but considerably reduced activity in extracts from fasted animals. Insulin administration reduced the sensitivity of the phosphatase reaction to glycogen inhibition. This could explain, at least in part, the increased phosphatase activity noted in the insulin-treated, fasted rats since glycogen was routinely added to the homogenizing buffer.     

Evidence of post-natal transmission of Neospora caninum in Dutch dairy herds

Eighteen dairy herds with neosporosis-associated abortions were analysed for antibodies against Neospora caninum. Blood samples of all cows, heifers and calves were collected on the same day for each farm. A total of 2430 heads of cattle were examined. For each herd, the seropositive and seronegative animals were plotted against month of birth. Analysis of seroprevalence in relation to age showed an equal distribution of seropositives in all age-groups in 10 herds. In contrast, in eight herds an age-group could be identified which had a significantly higher seroprevalence than the other animals in the herd. Most seropositive animals in the high seroprevalence age-groups had either seronegative dams or seronegative offspring, whereas there was a strong relationship between the serostatus of dams and offspring in the other animals in the herd. Aborting animals were mainly part of the high seroprevalence age-group. These findings strongly indicate a post-natal infection of the animals in the high seroprevalence age-groups, probably due to a point source exposure to N. caninum.