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21.
The mechanism and spread of pacemaker activity through myenteric interstitial cells of Cajal in human small intestine 总被引:5,自引:0,他引:5
Lee HT Hennig GW Fleming NW Keef KD Spencer NJ Ward SM Sanders KM Smith TK 《Gastroenterology》2007,132(5):1852-1865
BACKGROUND & AIMS: It has been generally assumed that interstitial cells of Cajal (ICC) in the human gastrointestinal tract have similar functions to those in rodents, but no direct experimental evidence exists to date for this assumption. This is an important question because pathologists have noted decreased numbers of ICC in patients with a variety of motility disorders, and some have speculated that loss of ICC could be responsible for motor dysfunction. Our aims were to determine whether myenteric ICC (ICC-MY) in human jejunum are pacemaker cells and whether these cells actively propagate pacemaker activity. METHODS: The mucosa and submucosa were removed, and strips of longitudinal muscle were peeled away to reveal the ICC-MY network. ICC networks were loaded with the Ca(2+) indicator fluo-4, and pacemaker activity was recorded via high-speed video imaging at 36.5 degrees C +/- 0.5 degrees C. RESULTS: Rhythmic, biphasic Ca(2+) transients (6.03 +/- 0.33 cycles/min) occurred in Kit-positive ICC-MY. These consisted of a rapidly propagating upstroke phase that initiated a sustained plateau phase, which was associated with Ca(2+) spikes in neighboring smooth muscle. Pacemaker activity was dependent on inositol 1,4,5-triphosphate receptor-operated stores and mitochondrial function. The upstroke phase of Ca(2+) transients in ICC-MY appeared to result from Ca(2+) influx through dihydropyridine-resistant Ca(2+) channels, whereas the plateau phase was attributed to Ca(2+) release from inositol 1,4,5-triphosphate receptor-operated Ca(2+) stores. CONCLUSIONS: Each ICC-MY in human jejunum generates spontaneous pacemaker activity that actively propagates through the ICC network. Loss of these cells could severely disrupt the normal function of the human small intestine. 相似文献
22.
KD McCloskey UA Anderson RA Davidson YR Bayguinov KM Sanders SM Ward 《British journal of pharmacology》2009,156(2):273-283
Background and purpose:
W/Wv and wild-type murine bladders were studied to determine whether the W/Wv phenotype, which causes a reduction in, but not abolition of, tyrosine kinase activity, is a useful tool to study the function of bladder interstitial cells of Cajal (ICC).Experimental approach:
Immunohistochemistry, tension recordings and microelectrode recordings of membrane potential were performed on wild-type and mutant bladders.Key results:
Wild-type and W/Wv detrusors contained c-Kit- and vimentin-immunopositive cells in comparable quantities, distribution and morphology. Electrical field stimulation evoked tetrodotoxin-sensitive contractions in wild-type and W/Wv detrusor strips. Atropine reduced wild-type responses by 50% whereas a 25% reduction occurred in W/Wv strips. The atropine-insensitive component was blocked by pyridoxal-5-phosphate-6-azophenyl-2′,4′-disulphonic acid in both tissue types. Wild-type and W/Wv detrusors had similar resting membrane potentials of −48 mV. Spontaneous electrical activity in both tissue types comprised action potentials and unitary potentials. Action potentials were nifedipine-sensitive whereas unitary potentials were not. Excitatory junction potentials were evoked by single pulses in both tissues. These were reduced by atropine in wild-type tissues but not in W/Wv preparations. The atropine-insensitive component was abolished by pyridoxal-5-phosphate-6-azophenyl-2′,4′-disulphonic acid in both preparations.Conclusions and implications:
Bladders from W/Wv mice contain c-Kit- and vimentin-immunopositive ICC. There are similarities in the electrical and contractile properties of W/Wv and wild-type detrusors. However, significant differences were found in the pharmacology of the responses to neurogenic stimulation with an apparent up-regulation of the purinergic component. These findings indicate that the W/Wv strain may not be the best model to study ICC function in the bladder. 相似文献23.
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JMG Crane T Delaney KD Butt KA Bennett D Hutchens DC Young 《The journal of maternal-fetal & neonatal medicine》2013,26(5):319-323
Objective: To identify independent predictors of successful labor induction with oral or vaginal misoprostol.Methods: Women enrolled in four previous randomized trials involving oral or vaginal misoprostol for cervical ripening and labor induction were included in the present cohort study, with dosing of 25–50?μg every 4 to 6?h vaginally (n?=?574) or 50?μg every 4?h orally (n?=?207). Multiple logistic regression was performed to identify factors independently associated with successful labor induction – defined as vaginal delivery within 12?h, vaginal delivery within 24?h and spontaneous vaginal delivery. Predictors of Cesarean birth and the need for only one dose of misoprostol were also identified. Variables included in the models were maternal age, weight, height, parity, gravidity, membrane status, route of misoprostol, gestational age, birth weight, and Bishop score and its individual components.Results: Maternal age, height, weight, parity, birth weight, dilatation, effacement and cervical station were associated with vaginal delivery within 24?h of induction. Maternal age, height, weight, nulliparity, birth weight and route of misoprostol were associated with Cesarean birth, with oral misoprostol being associated with a lower rate of Cesarean birth. The need for only one dose of misoprostol was predicted by maternal height, weight, parity, gestational age, Bishop score and route of misoprostol.Conclusion: Characteristics of the woman (height, weight, parity), the fetus (birth weight) and some of the individual components of the Bishop score, were associated with successful labor induction, with oral misoprostol being associated with a lower rate of Cesarean birth. 相似文献
26.
目的:综述人脂肪组织来源干细胞的生物学特性及其在缺血性心脏病中的应用,分析不足,并在此基础上提出未来研究要解决的问题,以期为临床治疗提供依据。资料来源:应用计算机检索Blackwell、Elsevier、Pubmed数据库1980/2007期间脂肪源性干细胞与缺血性心脏病方面的文献,检索词为“bone mesenchymal stem cells,adipose derived stemcells,cardiomyocytes,ischemic heart disease”等。应用计算机检索中国期刊全文数据库1980/2007期间相关文献,检索词为“骨髓间充质干细胞,脂肪组织来源的干细胞,心肌细胞,缺血性心脏病”等。并手工查阅相关书籍。资料选择:对资料进行初步选择:①脂肪组织来源干细胞的生物学特性。②脂肪组织来源干细胞治疗缺血性心脏病。排除重复文献。资料提炼:共搜集到相关文章57篇,删除内容重复及与本文主题关系较远的文章,剩余41篇作为综述参考。资料综合:脂肪组织来源干细胞与同样起源于中胚层的骨髓基质细胞不仅具有非常相似的生物学特性,而且在细胞表面标志谱的表达方面也非常相近。并且脂肪组织来源广泛,取材方便,可获得的基质细胞数量大,易于培养扩增。有研究发现,脂肪组织来源干细胞体外培养不需要任何诱导便能分化成具有自律性的心肌细胞,使得脂肪组织来源干细胞治疗缺血性心脏病成为可能。结论:脂肪组织来源干细胞在取材和增殖方面较骨髓间充质干细胞有优势;脂肪组织来源干细胞能较好的诱导为心肌细胞,将为缺血性心脏病的治疗提供更广阔的前景。 相似文献
27.
Hinsch E; Ponce AA; Hagele W; Hedrich F; Muller-Schlosser F; Schill WB; Hinsch KD 《Human reproduction (Oxford, England)》1997,12(8):1673-1681
Binding of mammalian spermatozoa to the zona pellucida and the induction of
the acrosome reaction are prerequisites for successful oocyte
fertilization. It has been postulated that xenobiotics that are released in
the environment as well as exposure to pharmaceutical medications may be
associated with reproductive problems in men and wildlife. Examining
physiological and non-physiological effects of particular compounds on
sperm functions requires high quality in-vitro test systems. We established
a reliable combined in-vitro test system with bovine gametes and evaluated
if aliquots of pooled post-thaw spermatozoa are suitable for examining
essential sperm functions. Using cryopreserved semen, the PSA-FITC/Hoechst
33258 staining procedure was applicable to evaluate the acrosomal status
and cell viability. In the bovine hemizona assay, hemizona indices revealed
no differences between cryopreserved and fresh semen. Treatment of
post-thaw bovine spermatozoa with progesterone (1 microM or bovine
follicular fluid (20%) induced the acrosome reaction from 12% (untreated
spermatozoa) to 25% (P < 0.001) and to 22% [corrected] (P < 0.01),
respectively. Incubation of both compounds (1 microM progesterone and 20%
follicular fluid) raised the percentage of acrosome-reacted spermatozoa to
30% (P < 0001). Our results demonstrate that cryopreserved semen can be
integrated into an in-vitro screening model for reproductive toxicology
testing. Pooled, cryopreserved bovine spermatozoa will thus permit
reproducible experiments for clinical and basic science purposes and may
also be applicable for the human system.
相似文献
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TR Fricke BA Holden DA Wilson G Schlenther KS Naidoo S Resnikoff KD Frick 《Bulletin of the World Health Organization》2012,90(10):728-738