排序方式： 共有4条查询结果，搜索用时 93 毫秒
1
1.
E van Engelen VNA Breeveld-Dwarkasing ME Everts GC van der Weyden MAM Taverne VPMG Rutten 《Reproduction in domestic animals》2009,44(2):303-311
The bovine cervix contains a large amount of smooth muscle cells distributed over an outer muscular layer and within a stromal layer. The stromal layer exhibits no electromyographic (EMG) activity at parturition. This leads to the question whether the stromal smooth muscle cells of the bovine cervix are prepared to contract with parturition, or whether they have another function. To this end, cervical biopsies were repeatedly taken from 10 pregnant cows at day-185 and -275 of gestation, at spontaneous, uncomplicated calving and at 30 days after calving. The smooth muscle bundles of the stroma were immunohistochemically analysed (n = 5) with regard to their integrity and cellular density, and the degree of staining for connexin-43, smooth muscle actin α (SMA), desmin and vimentin. Additionally, the mRNA expression for connexin-43, SMA, desmin and vimentin was determined with RT-PCR (n = 5). The smooth muscle tissue was arranged in bundles, also at parturition. However, the cellular density of these bundles and the SMA mRNA expression were decreased at parturition. Additionally, the SMA staining and connexin-43 expression and staining remained constant during pregnancy and at parturition. This might indicate that stromal smooth muscle cells are not prepared to contract with parturition, in contrast to the myometrial smooth muscle cells. The smooth muscle cells, stained for SMA, also expressed vimentin, and the proportion of co-expression was increased at day-275 of pregnancy. This suggests that the stromal smooth muscle cells predominantly have a secretory function in cows. 相似文献
2.
E van Engelen MW de Groot VNA Breeveld-Dwarkasing ME Everts GC van der Weyden MAM Taverne VPMG Rutten 《Reproduction in domestic animals》2009,44(5):834-841
The final stages of cervical ripening and parturition resemble an inflammatory process. Although the role of cytokines in both spontaneous and experimentally induced parturitions has been described in several small laboratory animals and humans, the involvement of pro‐inflammatory and regulatory cytokines in physiologic parturition in cows has not been determined. In this study, the cytokine expression profiles were assessed in bovine cervical tissue at several stages of pregnancy and at parturition. Serial biopsy samples of the cervix were obtained from 10 cows on day 185 and day 275 of pregnancy (which was on average 5.4 days before parturition) and at parturition. Messenger RNA expression levels of interleukin (IL)‐1β, IL‐6, IL‐8, IL‐10 and tumour necrosis factor (TNF)α were determined using real‐time polymerase chain reaction and the number of neutrophils and eosinophils was estimated by Luna and Sirius Red staining. At parturition, IL‐8 expression had increased 430‐fold (p < 0.001) when compared with that of the day 185 of pregnancy, large numbers of neutrophils had invaded the cervix while eosinophils remained scarce, IL‐1β had increased eightfold (p < 0.05) and IL‐6 had not changed significantly. Additionally, IL‐10 was increased by 10‐fold (p < 0.001) and TNFα decreased by 57% (p < 0.05) when compared with that of the day 185 of pregnancy. The large increase in expression of IL‐8, enabling the influx of neutrophils, is indicative of its important role in the final stage of cervical ripening and at parturition. As previous studies have shown that neutrophils excrete matrix metalloproteinases (MMP), this might contribute to softening of the cervix. In contrast, the only slightly increased levels of IL‐1, steady concentrations of IL‐6 and decreased TNFα, the potential consequences of increased IL‐10 expression, indicate that final cervical of cows in ripening at term parturition is an inflammatory process influenced by regulatory cytokines. 相似文献
3.
Taverne MA Breeveld-Dwarkasing VN van Dissel-Emiliani FM Bevers MM de Jong R van der Weijden GC 《Domestic animal endocrinology》2002,23(1-2):329-337
In the cow the foetal endocrine signals that initiate the calving process result in prepartum luteolysis. Withdrawal of progesterone (P4) action is a prerequisite for a normal calving. The rather abrupt declining influence of P4 is followed by a cascade of physiological processes in the myometrium and cervix. This contribution will focus on some of these events. Like in many other species, the myometrium in cows is not completely inactivated during pregnancy. So-called contractures have been registered during the final weeks of gestation and their EMG-characteristics in cows show a low frequency (on average: 13.6 per day) and long duration (on average 12.1 min). They are not evenly spread over the day because they occur less frequently when the cows are disturbed for feeding or cleaning their stables. Contractures affect several foetal functions. In the cow these contractures disappear during a period of about 8-9h when maternal plasma P4 levels are rapidly declining before calving. There is experimental evidence that this temporary inhibition is associated with prepartal luteal regression. The cause of this inhibition is still unknown. Because nitrous oxide inhibits smooth muscle cells and evidence in laboratory animals indicates that expression of the inducible form of nitrous oxide (iNOS) is downregulated in myometrium, but upregulated in the cervix around the onset of parturition, we started to investigate the role of this enzyme in bovine tissues around calving. By means of a RT-PCR technique, we obtained a first indication that iNOS is hardly expressed in the myometrium during calving, while expression was clearly detected at day 4 after calving. Analysis of prepartum en periparturient biopsies from myometrium and cervix with quantitative PCR is still underway. In six pregnant cows, provided with uterine EMG-electrodes and with ultrasonic crystals implanted on the caudal cervical rim to measure cervical dilatation, calving was induced with an injection of prostaglandin (PG) F2alpha. While maternal plasma P4 levels had significantly declined within 8h after PG treatment, the myometrium escaped from temporary inhibition with the development of a parturient contractility pattern on average at 13.5h after injection. However, it was only at 28 h after PG treatment that the first sustained increase of the opening of the vaginal ostium of the cervix was measured. 相似文献
4.
Bajcsy AC van der Weijden GC Doornenbal A Breeveld-Dwarkasing VN de Jong RC Szenci O Taverne MA 《American journal of veterinary research》2005,66(9):1605-1615
OBJECTIVE: To evaluate methods for on-farm measurements of uterine contractility in postpartum dairy cows by comparing data simultaneously recorded by use of 2 intrauterine pressure (IUP) devices and quantified electromyographic (EMG) signals. ANIMALS: 5 cows during the first 48 hours after parturition. PROCEDURE: 2 EMG electrodes were implanted on the surface of the gravid uterine horn. Parturition was induced by injection of a prostaglandin F2alpha analogue at day 274 of gestation. An open-tip catheter and pressure microtransducer were transcervically inserted and affixed to a caruncle immediately after calving. Changes in IUP were recorded concurrent with EMG recordings during 2-hour periods at 2, 6, 12, 18, 24, 36, and 48 hours after parturition. Novel acquisition and analysis software programs were used with a digital data-filtering capability for evaluation of IUP and EMG signals. RESULTS: The method for intrauterine fixation of the 2 pressure measurement instruments was effective and allowed easy, externally guided removal of the devices 48 hours after parturition. There was a high correlation between the data obtained by the 2 pressure measuring systems. Good correlation was also found between pressure data obtained by the open-tip catheter system and EMG signals. Although the quantified IUP and EMG signals were highly comparable, synchronization was not always evident during visual inspection of these signals. CONCLUSIONS AND CLINICAL RELEVANCE: The open-tip IUP catheter system with a special fixation method is suitable for use in on-farm studies. It will enable investigators to record natural and pharmacologically influenced uterine contractility in early postpartum dairy cows. 相似文献
1