国内生态恢复研究进展

本文介绍了生态恢复的研究进展,从生态恢复的定义、退化生态系统的指标等方面进行阐述,重点对国内在恢复生态学方面的进展做了介绍。对当前的人工草地、草地农业的研究情况做了一些概述。     

国内生态恢复研究进展

本文介绍了生态恢复的研究进展,从生态恢复的定义、退化生态系统的指标等方面进行阐述,重点对国内在恢复生态学方面的进展做了介绍.对当前的人工草地、草地农业的研究情况做了一些概述.     

论宋代对《史记》中管仲形象的接受

宋代,对士大夫来说这一可遇而不可求的特殊历史时期,成就了他们独特的人格结构和精神世界。他们对历史人物的看法尤异于前人,其中对管仲形象的接受就发生了颠覆性的变化。而宋人重新解读管仲的立足点也是宋代《史记》评论中普遍倾向的批评视角。     

Veterinary pathology in Europe in the light of the congresses of the European Society of Veterinary Pathology in the last decade

This paper presents the main trends in the activity of European veterinary pathologists in the context of their oral presentations (plenary lectures and short presentations) and posters provided during annual meetings of the European Society of Veterinary Pathology (ESVP), in the decade 1997-2006. It was found that the issue that was most often brought up in the meetings was organ pathology (566 presentations). Infectious and parasitical diseases were only slightly less frequent (548 presentations). Oncology was another common issue (404 presentations). During this decade, 52 plenary lectures were presented, 765 oral presentations and 1 072 posters. Altogether, 1 889 presentations were made, which is between 127 and 238 per year. Research by Polish scientists accounted for 3.16% of all presentations. Additionally, the subject matter discussed at the annual meetings is analysed, and the trends in the development of veterinary diagnostic pathology and broad pathology education are indicated. It is shown that veterinary pathology enhances knowledge in the field of veterinary medicine by fulfilling a cognitive and diagnostic role.     

Evidence for the non-involvement of the uterus in the lifespan of the corpus luteum in the cyclic dog

Progesterone levels in peripheral blood of dogs were analysed during the cycle in which hysterectomy (n = 5) or sham surgery (n = 3) was performed as well as during the cycle of dogs (n = 5) hysterectomized at least one year prior to this study; the data were compared with the findings in control dogs (n = 3). The averages of the duration of the luteal period observed in the three experimental groups were not significantly different from those of control dogs. Immediately after surgery, the progesterone level decreased from 25 to 50% of the presurgical level, but returned to presurgical level in about four days. Prolactin levels were elevated for about 30 h after surgery. Nevertheless, the averages of the mean prolactin levels for each animal during the luteal period of the experimental groups were not significantly different from those of control dogs. It is concluded that in the dog, the uterus is not involved in the lifespan of the cyclic corpus luteum.     

Physiological Changes in the Concentrations of Biotin in the Serum and Milk and in the Physical Properties of the Claw Horn in Holstein Cows

Physiological changes in the concentrations of biotin in the serum and milk and in the physical properties of the claw horn were examined in Holstein cows. A lower concentration of biotin in the serum and a higher concentration of biotin in milk were found during early and late lactation and during the dry period, and a significant (p<0.05) inverse correlation was found between serum and milk biotin concentrations. A high moisture content and a low level of hardness of the claw horn were found during mid-lactation. Our results indicate that change in the serum biotin concentration probably results from the loss of biotin in the milk of cows during each stage of lactation and also confirm that the moisture content and hardness of the claw horn undergo physiological changes.     

Application of the log-linear model in the prediction of the antinuclear antibody test in the dog

To find possible associations between antinuclear antibody (ANA) pattern, ANA titer, and certain clinical changes and clinical laboratory test results in dogs, the veterinary medical records of 111 ANA-positive and 126 ANA-negative dogs were examined. Variables could not be found that had significant associations with ANA pattern (unlike the results in persons), because of the predominance of 2 patterns. A log-linear model for ANA titer adequately fit the observed frequency and included 2-way interactions between titer and polyarthritis, titer and hematologic disorders, and polyarthritis and lymphadenopathy.     

Disturbance in the growth of the radius in dogs

In a 4-year period nine dogs have been met in which there was incomplete growth of the radius. The condition was unilateral in eight dogs and bilateral in one. Two were littermates. The defect is due to premature cessation of growth of the distal growth plate of the radius but the cause of this is not precisely known. It is recognized by characteristic radiographic changes in radius length, elbow joint space and premature closure of the distal growth plate of the radius. A method of surgical treatment has been devised and has proved beneficial in five dogs. Zusammenfassung. In einer Vierjahresperiode wurden neun Hunde beobachtet, bei denen ein unvollständiges Wachstum des Radius vorlag. Bei acht Hunden war der Zustand nur auf einer Seite zu finden, bei einem Hund auf beiden Seiten. Zwei der Hunde gehörten zum gleichen Wurf. Der Mangel ist auf verfrühte Wachstumseinstellung der distalen Wachstumsplatte des Radius zurückzuführen, jedoch ist die Ursache davon nicht genau bekannt. Er wird an charakteristischen radiographischen Veränderungen der Radiuslänge, des Ellbogengelenkzwischenraums und vorzeitigem Abschluss der distalen Wachstumsplatte des Radius erkannt. Es wurde eine chirurgische Behandlungsmethode entwickelt, die sich bei fünf Hunden als nutzlich erwies. Résumé. Au cows d'une période de 4 ans on a observé 9 cas de croissance incomplète du radius chez des chiens; l'anomalie était unilatérale dans 8 cas et bilatérale dans un cas; deux chiens appartenaient à la même portée. L'anomalie est due à l'arrêt prématuré de croissance de la plaque de croissance distale du radius, mais la cause n'en est pas encore connue d'une manière précise. Le diagnostic se fait par les signes radiologiques caractéristiques, modifications de la longueur du radius, de l'articulation du coude et soudure prématurée de la plaque de croissance du radius. On a élaboré une méthode de traitement chirurgical, qui s'est montrée favorable chez 5 chiens.     

蜂群分蜂行为研究进展

蜜蜂是多雄性真社会性昆虫,分蜂是这个庞大家族繁衍的重要手段,它们通过信息素和蜂舞来传递信息.群内工蜂是由不同亚家庭的全同胞姐妹和半同胞姐妹组成,它们在分蜂过程中扮演着不同的角色[1].它们自我组织如此有序,分工如此高效是十分值得我们深入研究的.     

The role of noradrenaline in the generation of the preovulatory LH surge in the ewe

Increasing plasma estrogen (E) levels during the follicular phase of the estrous cycle trigger the pre-ovulatory surge of gonadotropin-releasing hormone (GnRH)/LH. Noradrenaline (NA)-producing cells of the brain stem are involved in regulating GnRH cells and project to the preoptic area (POA) and bed nucleus of stria terminalis (BnST). Input to GnRH cells may be direct or indirect, via relay neurons in the POA/BnST. To investigate this, we ascertained whether an ₁-adrenergic antagonist would block/delay the LH surge in ovariectomised (OVX), E-treated ewes. E benzoate (EB) (50 μg) was injected (i.m.) and Doxazosin (100 nmol/h) or vehicle was infused into the third ventricle 2–26 h after EB injection. Doxazosin reduced the magnitude of the LH surge, but did not affect timing. To determine if NA is released in the POA/BnST of cyclic ewes, we immunostained dopamine-β-hydroxylase (DBH) in terminal fields. Reduced numbers of varicosities staining for DBH indicates release of NA. The number of varicosities immunostained for DBH was reduced in the dorsal and lateral BnST during the follicular phase and during the preovulatory LH surge compared to the luteal phase. These data suggest that noradrenergic mechanisms are involved in generation of the GnRH/LH surge via projections to the BnST and relay to GnRH cells. Since Doxasozin reduced the magnitude of the LH surge in the E-treated OVX ewe, and release of NA in cyclic ewes occurred during the follicular phase of the estrous cycle, we speculate that NA is a permissive factor in surge generation. Thus, increased noradrenergic activity is not a trigger mechanism for initiation of the surge.     

Modelling the transmission of Echinococcus granulosus in dogs in the northwest and in the southwest of Morocco

Echinococcus granulosus (E. granulosus) infection was studied in 151 dogs in two regions of Morocco: 68 dogs in the northwest (Loukkos) and 83 dogs in the southwest (Tiznit). The mean prevalence rates of echinococcosis in dogs were 58.82% (46.23-70.63%) in Loukkos and 55.42% (44.10-66.34%) in Tiznit and the mean abundances of E. granulosus per dog were 75 (59-93) and 547 (504-595), respectively. The mean abundance of E. granulosus in dogs was fitted to a negative binomial distribution by the maximum likelihood techniques to define parameters. E. granulosus was aggregated in dogs in the two regions. The prevalence of infection and the abundance of E. granulosus in dogs were fitted to mathematical models in order to determine if the parasite population is partly regulated by definitive host immunity. The best fit was obtained with the models assuming the presence of immunity. The mean time of exposure to infection was similar in the two regions and ranged from 8 months to about 2 years. The infection pressures (number of E. granulosus) obtained per dog each year were 65 (8-294) in Loukkos and 476 (316-886) in Tiznit. The proportion of dogs susceptible to infection was still high along the life of the dogs in Loukkos, while it was not different from zero in old dogs of Tiznit.     

抗氧化剂对家畜胚胎体外发育影响的研究进展

现在研究普遍认为活性氧自由基是导致胚胎体外发育阻滞的主要原因。本文主要综述了不同抗氧化剂对牛胚胎体外发育的影响,并分析其作用机制。     

雏鸭胸腺发育的增龄变化

通过对1～49日龄雏鸭胸腺组织学发育的增龄变化观察以及胸腺绝对重量、胸腺指数和外周血T淋巴细胞а-醋酸萘酯酶阳性率的测定,研究了雏鸭胸腺发育规律。结果表明：1～14日龄雏鸭胸腺生长较为缓慢;21～28日龄胸腺生长十分迅速,到28日龄时雏鸭胸腺中大部分T淋巴细胞已分化发育成熟,雏鸭胸腺已形成能有效产生细胞免疫的组织结构基础;35～49日龄胸腺发育已趋于稳定。文中对胸腺小体的形态进行了详细的描述,并对其功能进行了探讨。     

Role of Eicosanoids in the Regulation of the Periparturient Period in Cattle

Contents: In this review, the role of eicosanoids in regulation of parturition and the postpartum period was described with special emphasis on the bovine species. The metabolism of arachidonic acid and the production of eicosanoids during the peripartum period was discussed. Prostaglandin E₂ and F_2α (PGE₂, PGF_2α) play an important role in mechanisms controlling parturition. They are involved in luteolysis, uterine contractions and dilation of the cervix. Eicosanoids also seem to influence the loosening processes of the fetal membranes. However, in the literature, conflicting results were found. Many investigations suggested that retained placental membranes could be related to low PGF_2α production and/ or an imbalance of arachidonic acid metabolism in the uterus. The possible role of the lipoxygenase pathway metabolite 15-hydroxy-eicosatetraenoic acid (15-HETE) in expulsion of the fetal membranes was also discussed. As far as the postpartum period is concerned, a relationship between postpartum PGF_2α release and the involution of the uterus was found. Cows with undisturbed uterine involution had higher PGF_2α production than cows with delayed involution. In contrast to the positive effect of PGF_2α on uterine involution, PGE₂ seems to delay the involution processes. Further experiments are necessary in order to study the function of eicosanoids in mechanisms regulating parturition, release of the fetal placental membranes and involution of the uterus.