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1.
A cosmid, pR4C1, composed of the actinophage R4 cos sequence and Streptomyces plasmid pIJ365, was encapsidated in R4 phage particles in vivo. [T. Morino et al., Mol. Gen. Genet., 198, 228–233 (1985)] In this report a cosmid derivative, pR4C4, is shown to be also encapsidated by heterogeneous actinophages, SPA10 and SPA38, and transferred to Streptomyces lividans. Use of this transduction and conservation of the DNA packaging mechanism are discussed.  相似文献   

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脑苷脂B的结构鉴定   总被引:2,自引:0,他引:2  
利用波谱(FABMS、NMR和IR)和化学的方法详细鉴定了真菌黄白红菇Russulaochroleuca(Pers.)Fr.和印度块菌Tuber inddicum Cooke et Massee中存在的9-methyl-4,8-sphingadienine型脑苷脂cerebrosideB(1);1-O-β-D-吡喃葡萄糖基-(2S,3R,4E,8E,2′R,)-2-N-(2′-羟基棕榈酰)-9-甲基-4,8-sphingadienine。化合物1为首次被发现存在于这2种真菌中。  相似文献   

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The ontogenetic appearance of three independant spermatozoa autoantigens (S, P and T) has been studied in guinea pig germinal cells by immunofluorescence and comparison with cytology and histological structures during early maturation of seminiferous tubule cells. The maturation of 120 testes from 60 guinea pigs studied from day 1 to day 50 after birth has shown an evolution in 3 periods. During the first, or negative, period (day 1 to day 25), only spermatogonia (from day 1) and spermatocytes I (from day 16) are present. No significant PAS-positive formations are seen and no autoantigen is detected. During the second, or transitional, period (day 26 to 29), spermatocytes II and spermatids appear as well as paranuclear PAS-positive golgian proacrosomal and acrosomal granules. At the same time, the three autoantigens S, P and T are detected on the same PAS-positive formations with a frequency that increases from day to day. During the third, or positive, period (from day 30) all testes present cells with PAS-positive formation, progressive maturation of acrosomes in spermatids and appearance of spermatozoa (present on day 39) leading to the adult structure of seminiferous tubules. The three autoantigens are constantly present during that period. The simultaneous appearance of the 3 antigens in haploid germinal cells (spermatids and possibly spermatocytes II) as an early expression of cytodifferentiation and their total absence from diploid germinal cells (spermatogonia and spermatocytes I) seem to be of biological significance.  相似文献   

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Behavioural phenotypes can be studied from a variety of perspectives. Recent developments have focused on the individual, seeking patterns of behaviour that are stable over time and/or across different contexts (animal personalities). This study applied this method of understanding individual behavioural variability to domestic guinea pigs. Two behavioural domains were investigated: emotionality and social behaviour. Additionally, individual cortisol–stress reactivity and dominance status were examined. Adult male domestic guinea pigs living in large mixed‐sex colonies were subjected to a series of behavioural and physiological tests twice with an intertest interval of 8 wk. Individual consistency over time was found regarding social behaviour, cortisol reactivity and dominance status, whereas no stability regarding emotional behaviour was detected. Furthermore, no stability over contexts was found. Our results suggest that the concept of animal personality is applicable to domestic guinea pigs. The ecological relevance of these data is underscored by the fact that they were obtained in animals from a very rich, socially complex scenario. Moreover, our study highlights that behaviour alone is not sufficient to describe individual phenotypic consistency. Physiological parameters such as stress reactivity should be included in animal personality research. Furthermore dominance – a relative measure which is not an absolute attribute of individuals – proved to be stable over time and thus also shed light on individuality.  相似文献   

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An experimental model of nonbacteremic pneumonia with a virulent strain of Pseudomonas aeruginosa was successfully established in guinea pigs immunosuppressed with cortisone acetate although the organisms were eliminated rapidly from the lungs without cortisone treatment. Using a pocket nebulizer, almost all the animals which received 106 organisms/g-lung developed bronchopneumonia without any septic findings as long as 10 days after challenge. The lesions produced in such animals were characterized by dissemination of multiple purulogranulomatous changes. In the early stage of infection, infiltration of polymorphonuclear cells (PMNs) in the bronchiolar and alveolar spaces was diffuse, later showing multifocal accumulation with the formation of central spherical grains enclosing bacterial colonies. In the later stage, granulation tissue consisting of large mononuclear cells, fibroblasts and collagen fibers developed around the PMN accumulation. The animals which received 107 organisms/g-lung, on the other hand, developed severe pulmonary hemorrhages and necrosis followed by septic death.  相似文献   

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目的探索并建立豚鼠光过敏试验的方法。方法采用TBS作为阳性对照物,同时设立阴性对照组。分别于第1天、第4天、第7天对豚鼠皮肤进行UV-A紫外光诱导,诱导剂量紫外光强度为30 J/cm2;于第一次诱导后28 d对豚鼠皮肤采用UV-A紫外光激发,激发强度为9 J/cm2。结果阴性对照组24 h、48 h、及72 h豚鼠光过敏试验阳性率均为0,阳性对照组为24 h、48 h、及72 h豚鼠光过敏试验阳性率均为100%。结论本研究成功建立了豚鼠皮肤光过敏试验模型,TBS可作为阳性对照物。  相似文献   

11.
Immunogenicity of Plague Vaccines in Mice and Guinea Pigs   总被引:2,自引:0,他引:2       下载免费PDF全文
The median effective doses (ED50) of 28 lots of killed Pasteurella pestis strain 195/P vaccine were determined in mice and guinea pigs. Mice were injected with vaccine alone, whereas guinea pigs received vaccine suspended in incomplete Freund's adjuvant. Potency ratios of vaccines were obtained by comparing the ED50 of the test with that of a reference vaccine. Mean potency ratios of 1.82 ± 0.50 in mice and 3.22 ± 0.56 in guinea pigs were obtained, and the difference between these means was significant, P = <0.01. The number of organisms in the challenge dose did not significantly affect the ED50 of a vaccine in guinea pigs. However, irrespective of vaccinating route, nearly 1,000 times as much vaccine was required in the absence of adjuvant as in its presence to produce comparable protective indexes in the guinea pig. The response of guinea pigs did not offer any improvement over mice in evaluating the efficacy of plague vaccines.  相似文献   

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A suspended cell culture procedure was described for the cultivation of guinea pig macrophages infected with Salmonella typhimurium. The fate of the intracellular bacteria was assessed by quantitative recovery of viable bacteria with 0.5% solution of sodium desoxycholate. Two strains of S. typhimurium with different degrees of virulence for mice were compared. There was an initial destruction of intracellular bacteria of both strains; however, the extent of this destruction differed. Approximately 1% of the avirulent bacteria initially phagocytized survived at the end of 4 hr, whereas approximately 8% of the virulent bacteria survived at the end of 3 hr. After this initial killing, the intracellular bacteria began to multiply at a logarithmic rate between 3 and 21 hr after phagocytosis, and then a stationary phase was attained. The rate of this multiplication was comparable for both strains.  相似文献   

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用附红细胞体分别感染FMMU白化豚鼠和普通花色豚鼠,同时测定两组豚鼠的红细胞免疫功能,探讨FMMU白化豚鼠的免疫学特性与病原体敏感性之间的关系。结果表明,FMMU白化豚鼠对人附红细胞体比普通花色豚鼠敏感。封闭群FMMU白化豚鼠有独特的免疫学特性,红细胞免疫功能低于普通花色豚鼠,对病原体敏感性高于普通花色豚鼠,更适于建立感染性疾病动物模型。  相似文献   

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Drug-induced torsades de pointes (TdP), a life-threatening arrhythmia associated with prolongation of the QT interval, has been a significant reason for withdrawal of several medicines from the market. Prolongation of the QT interval is considered as the best biomarker for predicting the torsadogenic risk of a new chemical entity. Because of the difficulty assessing the risk for TdP during drug development, we evaluated the metabolic phenotype for predicting QT prolongation induced by sparfloxacin, and elucidated the metabolic pathway related to the QT prolongation. We performed electrocardiography analysis and liquid chromatography–mass spectroscopy-based metabolic profiling of plasma samples obtained from 15 guinea pigs after administration of sparfloxacin at doses of 33.3, 100, and 300 mg/kg. Principal component analysis and partial least squares modelling were conducted to select the metabolites that substantially contributed to the prediction of QT prolongation. QTc increased significantly with increasing dose (r = 0.93). From the PLS analysis, the key metabolites that showed the highest variable importance in the projection values (>1.5) were selected, identified, and used to determine the metabolic network. In particular, cytidine-5′-diphosphate (CDP), deoxycorticosterone, L-aspartic acid and stearic acid were found to be final metabolomic phenotypes for the prediction of QT prolongation. Metabolomic phenotypes for predicting drug-induced QT prolongation of sparfloxacin were developed and can be applied to cardiac toxicity screening of other drugs. In addition, this integrative pharmacometabolomic approach would serve as a good tool for predicting pharmacodynamic or toxicological effects caused by changes in dose.  相似文献   

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Introduction

The phosphodiesterase-III inhibitor milrinone improves ventricular contractility, relaxes pulmonary arteries and reduces right ventricular afterload. Thus, it is used to treat heart failure and pulmonary hypertension (PH). However, its action on pulmonary veins (PVs) is not defined, although particularly PH due to left heart disease primarily affects the pulmonary venous bed. We examined milrinone-induced relaxation in PVs from guinea pigs (GPs) and humans.

Material and Methods

Precision-cut lung slices (PCLS) were prepared from GPs or from patients undergoing lobectomy. Milrinone-induced relaxation was studied by videomicroscopy in naïve PVs and in PVs pre-constricted with the ETA-receptor agonist BP0104. Baseline luminal area was defined as 100%. Intracellular cAMP was measured by ELISA and milrinone-induced changes of segmental vascular resistances were studied in the GP isolated perfused lung (IPL).

Results

In the IPL (GP), milrinone (10 µM) lowered the postcapillary resistance of pre-constricted vessels. In PCLS (GP), milrinone relaxed naïve and pre-constricted PVs (120%) and this relaxation was attenuated by inhibition of protein kinase G (KT 5823), adenyl cyclase (SQ 22536) and protein kinase A (KT 5720), but not by inhibition of NO-synthesis (L-NAME). In addition, milrinone-induced relaxation was dependent on the activation of KATP-, BKCa 2+- and Kv-channels. Human PVs also relaxed to milrinone (121%), however only if pre-constricted.

Discussion

Milrinone relaxes PVs from GPs and humans. In GPs, milrinone-induced relaxation is based on KATP-, BKCa 2+- and Kv-channel-activation and on cAMP/PKA/PKG. The relaxant properties of milrinone on PVs lead to reduced postcapillary resistance and hydrostatic pressures. Hence they alleviate pulmonary edema and suggest beneficial effects of milrinone in PH due to left heart disease.  相似文献   

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《Anthrozo?s》2013,26(3):445-458
ABSTRACT

This study investigated the effects of a classroom-based animal-assisted activities (AAA) program with guinea pigs on the social functioning of primary school children. We hypothesized that participants in the experimental condition (n = 64), compared with a waitlist control group (n = 64), would demonstrate improvements in social functioning following the program. Parents and teachers used the Social Skills Rating System (SSRS) to evaluate the social skills and problem behaviors of 128 participating children (age range = 4.8 to 12.7 years) before and after an 8-week period. Teachers also rated academic competence at both time points. Children who participated in the AAA program demonstrated significantly greater improvements in social functioning than their control group peers, as defined by greater increases in social skills (teacher SSRS) and decreases in problem behaviors (parent and teacher SSRS). There were no significant differences between the groups in academic competence. AAA participants demonstrated significant increases in social skills and decreases in problem behaviors from pre- to post-program on the teacher version of the SSRS. Control group participants did not show significant changes on these measures. These findings suggest that an AAA program with guinea pigs may be a feasible addition to the primary school classroom in order to improve social functioning. Further component analysis will be necessary to determine whether the animal is the active ingredient in AAA programs of this nature.  相似文献   

20.
The relation between copper alginate fibers and immunotoxicity in animals was studied by dividing guinea pigs and mice into control groups and experimental groups. Varied weights of fibers were subcutaneously embedded in the experimental groups, whereas the control groups were operated on simulatively. Morphology analysis, erythrocyte osmotic fragility (EOF) test, direct plaque-forming cell (PFC) assay, quantitative hemolysis spectrophotometry (QHS) assay, macrophages phagocytosis assay, and pathology analysis were used to examine morphology, microstructure, and immunotoxicity. With increasing doses of copper alginate fibers, the EOF of experimental groups increased in contrast with the control group. Moreover, the antibody level decreased based on the results of the PFC and QHS assays, and macrophages phagocytosis descended in relation to dose. However, the immune functions were weakened without time dependence. According to pathologic photographs, the partial organs were damaged, implying bad histocompatibility. Hence, copper alginate fiber is proved to be a harmful material for medical devices.  相似文献   

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