通肠散对小鼠小肠推进率及兔离体空肠运动性能的影响

通过通肠散对小鼠小肠推进率的影响及对兔离体空肠作用的研究,观察通肠散的泻下作用,并探讨通肠散的泻下作用机理。取通肠散和墨汁的混合物及生理盐水和墨汁的混合物,小鼠灌胃,取小肠测定其推进率;取兔离体空肠,分别加入通肠散0.02mL、0.04mL、0.06mL、0.08mL,以给药前为空白对照,观察对兔离体空肠的作用;取兔离体空肠,分别加入通肠散、硫酸阿托品、肾上腺素、硝苯地平0.02mL,分别观察对通肠散至兔离体空肠兴奋作用的影响。试验组小鼠灌胃后,提高了小鼠小肠的推进率,与对照组相比差异极显著(p＜0.01);通肠散各剂量组对兔离体空肠的最大张力、最小张力、平均张力、收缩频率均有显著提高,与对照组相比差异极显著(p＜0.01),且存在量效关系;硫酸阿托品、肾上腺素可拮抗通肠散对兔离体空肠的兴奋作用,硝苯地平对通肠散对兔离体小肠的兴奋作用无显著影响。通肠散可以提高小鼠小肠的推进率,对兔离体空肠具有兴奋作用,且该兴奋作用可被硫酸阿托品、肾上腺素所拮抗。     

Immunological detection of cardiac glycosides in plants

Summary Australian native and introduced plants were examined, using digoxin immunoassays, to detect the presence of cross-reacting cardiac glycosides. These compounds were found in 27 species from 20 genera. The assay technique can also be used on serum samples to confirm cardiac glycoside ingestion.     

Use of an isolated intestinal circuit to evaluate the effect of ischemia and reperfusion on mucosal permeability of the equine jejunum

OBJECTIVES: To evaluate the efficacy of an isolated perfusion circuit and the effect of ischemia-reperfusion on mucosal permeability of the jejunum. STUDY DESIGN: In vitro study of intestinal mucosal permeability. ANIMALS: Twelve healthy adult horses. METHODS: A control segment of jejunum was placed in an isolated perfusion circuit for 240 minutes and mucosal permeability was measured. After detecting no deleterious effects of the isolated system on the control intestine, low flow ischemia was created in experimental segments for 20, 40, 60 and 90 minutes followed by 60 minutes of reperfusion and mucosal permeability was evaluated. At the completion of the studies, histologic evaluation was used to determine mucosal grades, surface area, and volume. RESULTS: Control tissue was maintained in the isolated circuit for 240 minutes without effect on mucosal grade, surface area, or volume relative to intact tissue. After ischemia-reperfusion, mucosal grade increased, and volume and surface area decreased progressively with longer periods of ischemia. Mucosal clearance of albumin remained constant during 240 minutes of perfusion in control tissue and was elevated after ischemia-reperfusion. CONCLUSIONS: No deleterious changes were noted in jejunum perfused with this isolated circuit, whereas alterations in mucosal permeability were present after ischemia-reperfusion. CLINICAL RELEVANCE: The isolated perfusion circuit successfully maintained an isolated segment of jejunum within physiologic limits, and can be used to evaluate the effects of injury and the efficacy of pharmaceuticals to attenuate these changes.     

高温处理对三种益生菌的影响

在使用颗粒料饲喂动物的时候，益生菌添加剂必须与饲料混合制粒后才能饲喂动物，在饲料制粒过程中，制粒温度可能会对益生菌的存活产生潜在的负面影响，为了了解制粒温度对益生菌的影响情况，本试验通过对两株芽孢杆菌和一株酵母菌高温处理，模拟饲料制粒过程中温度对它们的影响。为该3种益生菌     

The toxicity to cattle and bufadienolide content of six Bryophyllum species

SUMMARY: Cardiac glycoside poisoning was produced in calves given (in descending order of toxicity) flower heads of the hybrid Bryophyllum (Kalanchoe) daigremontianum x B. tubiflorum, of B. pinnatum, of B. tubiflorum (from previous work), whole plant of B. fedtschenkoi, flower heads of B. daigremontianum and whole plant of B. proliferum. For each plant (except B. tubiflorum), 2 calves were each given a single dose of 20 g wet weight per kg bodyweight. By using high performance liquid chromatography, the bufadienolides (cardiac glycosides) bryotoxin A, B and C were detected and assayed in the flower heads and leaf plus stem of B. tubiflorum and in the roots of B. tubiflorum, the hybrid and B. pinnatum. Only bryotoxins B and C were detected and assayed in the flower heads and leaf plus stem of the hybrid, B. daigremontianum and B. pinnatum. No bryotoxins were detected in B. fedtschenkoi. Bryotoxin A and a mixture of bryotoxins B and C from B. tubiflorum flowers were used as standards in the chromatographic assay. Comparing the results of the calf toxicity experiment with the amounts of bufadienolide measured in the plants suggests that bryotoxins A, B and C probably account for the observed disease, but that B. pinnatum and B. fedtschenkoi contain at least one other cardiac glycoside.     

The effect of xylazine on the isolated sheep trachea

The effect of xylazine on the isolated sheep trachea and its possible interactions with the α₂-adrenergic antagonist, atipamezole, and the anticholinergic agent, atropine, was studied. The mechanical responses of the tracheal preparations were recorded after exposing each one to cumulatively increasing concentrations of xylazine alone or in the presence of atipamezole or atropine.
Xylazine exerted a concentration-dependent contractile effect, with a threshold concentration of 10^--⁷M while the maximum activity was produced at a concentration of 10^--⁵M (EC₅₀= 2.3 × 10^--⁷). This xylazine-induced contractile effect was inhibited by atipamezole, but not significantly modified by atropine. Thus, it is concluded that α₂-adrenoceptors exist in the sheep trachea and it is suggested that α₂-adrenoceptor agonists may act on airways in sheep directly through stimulation of peripheral α₂-adrenergic receptors and indirectly via central α₂-adrenergic receptor activation of parasympathetic tone.     

The effect of hypothyroidism on cardiac function in dogs

The thyroid hormones have direct and indirect effects on the heart. So it is possible that depression of left ventricular function is associated with hypothyroidism. This publication describes cardiac findings (auscultation, electrocardiography, echocardiography) in ten hypothyroid dogs. Low heart rates, reduced R-amplitudes and bradycardic arrhythmias (first and second-degree AV block) were found on the electrocardiogram before treatment. On the echocardiograms most of the dogs showed reduced contractillity and reduced left ventricular wall thickness. Seven dogs were reexamined after levothyroxine supplementation. Effects of treatment were increased heart rates and R-amplitudes as well as disappearance of the bradycardic arrhythmias in electrocardiographic examination. The echocardiographic examination showed increased contractility and increased left ventricular wall thickness.     

Endothelin receptor mediating contraction of isolated bovine coronary artery

We studied endothelin (ET) receptors and their subtypes on isolated bovine coronary arteries. Endothelin receptors that mediated contraction of isolated bovine coronary artery were characterized by the use of antagonists and agonists. Contractions induced by the nonselective agonist ET-1 (10-10-10-7 M) were not affected by the removal of the endothelium (pEC50: 8.52, maximal contraction: 105% of that induced by 60 mM KCl). BQ-123 (3 x 10-7 M) antagonized contractions of endothelium-denuded coronary rings induced by low concentrations of ET-1 (10-10 or 10-9 M), but potentiated the contractions induced by higher concentrations of ET-1 (3 x 10-8 and 10-7 M). BQ-788 (10-6 M) potentiated contractions induced by ET-1 (3 x 10-10 and 10-7 M). In the presence of BQ-788 (10-6 M), BQ-123 (3 x 10-8-3 x 10-6 M) concentration - dependently inhibited contractions induced by ET-1 (3 x 10-10 and 10-7 M) (pA2: 6.61). Sarafotoxin S6b (10-9-3 x 10-7 M) evoked contractions in the denuded coronary artery (pEC50: 8.49, maximal contraction: 139% of 60 mM KCl). The BQ-123 caused a concentration-dependent rightward shift of contractions induced by sarafotoxin S6b (pA2: 7.89). The present study indicates that ET-1 and sarafotoxin S6b contract the isolated bovine coronary artery by stimulating ETA receptors on smooth muscle cells, and that ETB receptors might suppress the ET-1-induced contractions.     

Influence of the dietary potassium content on transepithelial potassium transport in rat jejunum

In a recent study, we found that the distal rat jejunum is able to secrete K⁺ under in vitro conditions. The question therefore arises as to whether the small intestine might participate in K⁺ homeostasis. Consequently, this study examined the influence of the dietary K⁺ content on transepithelial K⁺ transport in rat jejunum. Rats were fed two diets differing in K⁺ content (control diet 4.0 g K⁺/kg, low K⁺ diet (LK) 0.27 g K⁺/kg). After a minimal feeding period of 7 days, distal jejunal sheets were mounted in Ussing chambers and unidirectional ⁸⁶Rb⁺ fluxes (as a marker for K⁺ transport) were measured under short‐circuit conditions. Jejunum obtained from rats fed the control diet showed a net K⁺ secretion of 200 nmol Rb⁺/h/cm². Unidirectional Rb⁺ fluxes were smaller in distal jejunum from rats fed the LK diet. In these tissues, glucose‐induced short‐circuit current and tissue conductance were also smaller than in controls. However, net Rb⁺ fluxes were not significantly different in small intestine from K⁺‐restricted rats compared with jejunum from control animals. Based on the observation that the dietary K⁺ content does not affect transepithelial net K⁺ transport, we conclude that transcellular K⁺ secretion by the small intestine is not involved in K⁺ homeostasis.     

The effect of polyphosphates on streptococci isolated from mastitis cases

The effect of 0.01, 0.02, 0.03, 0.05, 0.6, 0.8 and 0.9% of polyphosphate mixture on 5 strains of Streptococcus agalactiae, 2 strains of Streptococcus dysgalactiae and 3 strains of Steptococcus uberis in blood agar in vitro and in milk was examined. It was found that the growth of all strains of the above mentioned bacteria was completely inhibited by 0.03% phosphate mixture in blood agar. In milk, however, the amount of polyphosphate mixture necessary for total inhibition was, from 0.6 to 0.9%, depending on the strain.     

The toxic effects on cardiac myocytes of tyledoside F, a cumulative neurotoxic cardiac glycoside isolated from Tylecodon grandiflorus

To investigate the cardiac cellular effects of tyledoside F, a cumulative neurotoxic bufadienolide and ouabain, a non-cumulative cardenolide, the whole-cell clamp method was used to measure the Na-K pump current after the Na-K pump had been activated by high intracellular Na2+. The toxic effects of tyledoside F and ouabain on cardiac myocytes were also investigated by observing the effect of the Ca2+ overload on the variability of myocytes during a period of 75 min. From the results it is clear that there are similarities in the direct effects of tyledoside F and ouabain on the Na-K pump. It was found that ouabain inhibited the Na-K pump current more than that of tyledoside F. With regard to Ca2+ overload, there are differences in their mode of production of Ca2+ overload because cinnarizine protects the myocytes against ouabain-induced Ca2+ overload but not against tyledoside-induced Ca2+ overload. This study shows that with the whole-cell clamp technique tyledoside F inhibited the Na-K pump in a manner similar to inhibition of the pump by ouabain. Viability studies with myocytes indicated that tyledoside F also has other effects which are different from these of ouabain.     

Morphologic and ultrastructural evaluation of effect of ischemia and dimethyl sulfoxide on equine jejunum

Morphologic changes in equine jejunal segments subjected to 1 hour of ischemia and 1 hour of reperfusion, and protective effects of systemic administration of dimethyl sulfoxide (DMSO; 1 g/kg of body weight) were investigated in 18 ponies, using light microscopy and scanning and transmission electron microscopy. Ponies were allotted to 4 groups: group 1--control (n = 3); group 2--DMSO (n = 3); group 3--ischemia (n = 6); and group 4--ischemia and DMSO (n = 6). In each pony, 2 jejunal sections were evaluated. The first section was obtained prior to induction of ischemia, and the second was obtained 2 hours later after reperfusion. Mucosal lesions were graded from 0 (normal) to 5 (most severe). Combined ischemia and reperfusion of 2 hours' duration induced moderately severe mucosal injury to the equine jejunum (group 3; grade 1.5 to 2.5), characterized principally by disruption of enterocyte attachment from the basement membrane and lamina propria. Fluid accumulation disrupted enterocyte cell-to-cell adhesion toward cell bases, while apical tight junctions and desmosomal junctions toward the luminal surface remained intact. Intracytoplasmic organellar changes within enterocytes were not a prominent feature of the injury. The aforementioned processes were marked at the villus tip and progressed down the villus sides. These findings support the importance of mechanisms leading to early subepithelial fluid accumulation rather than that of direct severe enterocyte injury. Further, fluid accumulation does not appear to arise from intercellular migration from the luminal surface. In this model, a pathomechanical effect caused by vigorous villus retraction appears to exacerbate epithelial lifting toward the villus tip.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of terguride on contractility of rat uterine strips

The effects of terguride on the uterotonic activity of rat's uterine stria were investigated by means of a standardized isometric method of measuring in vitro the contractility of uterine muscles. The uterotonic activity of the given preparation depends on its concentration and on the phase of uterine cycle. The uterotonic activity makes 71.4 U.mg-1 in the range of terguride concentrations from 10(-7) to 10(-5) mg per ml. Used at higher concentrations, the uterotonic activity of terguride is very low. Spontaneous contractions are moderated and the tone of uterus is decreased by terguride administration.     

The effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities

In this study, the effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities was investigated. Forty male BALB/c mice were used as material. Ten mice served as a control group, and 30 mice were injected with tilmicosin (25 mg/kg body weight, subcutaneously, with a single injection). After drug administration, they were monitored for 3 days. Tilmicosin caused decreases in cardiac superoxide dismutase and glutathione peroxidase activities.     

The microbiologic ecology of the turkey poult jejunum

Microbial succession in the jejunum of the commercial turkey poult was elucidated from poults at three different ranches and from successive flocks on a fourth ranch. The microbial ecology of the jejunum appears to consist of Gram-positive organisms in the first few days. The bacterial ecology then primarily becomes a Gram-negative flora. After 3 weeks of age, Escherichia coli, Lactobacillus spp. and Campylobacter jejuni dominate the jejunum and this observations is not affected by the time of year of sample collections. It is speculated that this progression and colonization of a dominant jejunal flora is a natural way for poults to prevent pathogenic bacteria from gaining a foothold.     

三种药物防治猪喘气病的效果观察

为治疗湖南省某大型外贸猪场自然感染的猪喘气病(猪支原体肺炎,MPS),采用支原净 土霉素、支原净、泰乐茵素这几种药物分高低剂量组进行了对比治疗试验。结果发现,用支原净 土霉素高低剂量组的治愈率均为90％,单独使用支原净的高剂量组治愈率为85％,低剂量组治愈率为75％;单独用泰乐茵素的高剂量组治愈率为75％,低剂量组治愈率为65％。试验表明：支原净 土霉素对猪喘气病的疗效最好。     

镉致大鼠睾丸损伤及葛根素的保护作用

24只4周龄雄性SD大鼠,分成4组并每天按以下处理:对照组灌服蒸馏水(10 mL/kg);葛根素组每日按照100mg/kg的用量灌服葛根素;镉组按照2mg/kg的Cd2+用量腹腔注射氯化镉溶液(10g/L);镉+葛根素组,在镉组的处理基础上,再按照100mg/kg的用量灌服葛根素。4周后,将大鼠麻醉并处死,摘取睾丸称其质量并计算脏器系数,睾丸制成组织匀浆检测大鼠睾丸中过氧化氢酶(CAT)、还原型谷胱甘肽(GSH)和丙二醛(MDA)的含量,并制作睾丸病理切片显微镜观察。结果显示与对照组相比,镉组大鼠睾丸脏器系数极显著降低(P0.01);睾丸组织中CAT和MDA的含量显著或极显著增加(P0.05或P0.01),GSH含量极显著减少(P0.01);与镉组相比,镉+葛根素组睾丸脏器系数极显著升高(P0.01);睾丸组织中CAT和MDA的含量显著降低(P0.05),GSH含量显著增加(P0.05)。病理切片显示镉组大鼠睾丸组织的细胞出现实化,看不到各级睾丸细胞正常结构,镉+葛根素组与镉组相比,睾丸细胞损坏程度都有所减轻。本试验表明镉对大鼠睾丸有损伤作用,而葛根素能减轻这种损伤,对镉致大鼠睾丸损伤具有保护作用。