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Effects of Bordetella pertussis toxin pretreatment on the antiarrhythmic action of ischaemic preconditioning in anaesthetized rats.
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1. Bordetella pertussis toxin, which catalyses the ADP-ribosylation of certain guanine nucleotide binding proteins (G proteins), thus functionally uncoupling them from associated receptors, was examined to determine whether it modified the antiarrhythmic effect of ischaemic preconditioning in anaesthetized rats. 2. Pertussis toxin (25 micrograms kg-1, i.p., 48 h prior to heart isolation) attenuated the negative chronotropic effect of acetylcholine (ACh) in rat isolated Langendorff perfused hearts. ACh (10 microM) reduced heart rate by 4% in hearts taken from pertussis toxin-treated animals, compared to a reduction of 57% in hearts taken from animals treated only with vehicle. 3. In anaesthetized rats, ischaemic preconditioning (a single 3 min occlusion of the left main coronary artery followed by 10 min reperfusion) had a pronounced antiarrhythmic effect during a subsequent 30 min period of regional myocardial ischaemia. Compared to hearts receiving only a 30 min period of left coronary occlusion, there was a reduced mortality (67% and 0% for control and preconditioned groups, respectively; P < 0.01) and decreased incidences of ventricular tachycardia (VT) and ventricular fibrillation (VF). Pretreatment with pertussis toxin (25 micrograms kg-1, i.p., 48 h previously) did not modify the arrhythmias associated with a 30 min period of regional myocardial ischaemia, neither did it modify the reduction in mortality (from 56% to 0%; P < 0.05) associated with preconditioning. Furthermore, the decrease in total ventricular premature beat count induced by preconditioning seen in controls (from 427 +/- 130 to 95 +/- 45) was also seen in pertussis toxin-treated rats (from 252 +/- 190 to 57 +/- 25).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Early mobilisation after percutaneous cardiac catheterisation using collagen plug (VasoSeal) haemostasis.
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OBJECTIVE--To assess the efficacy and safety of a haemostatic bovine collagen plug (VasoSeal) in reducing patient immobilisation after cardiac catheterisation from a percutaneous femoral arterial approach. DESIGN--A non-randomised, prospective analysis of a new biodegradable haemostatic agent on an intention to treat basis. SETTING--The catheterisation suite of a regional cardiothoracic unit. PATIENTS--A series of 63 patients having various diagnostic investigations and therapeutic interventions agreed to participate in this study. INTERVENTIONS--Cardiac catheterisation was performed from a percutaneous femoral artery approach. Patients taking aspirin and those who required formal anticoagulation were not excluded. Patients were measured for the appropriate sized collagen delivery system at the beginning of the procedure. At the end of the procedure two bovine collagen plugs were applied to the surface of the femoral artery through the channel created by the application device. MAIN OUTCOME MEASURES--Incidence of successful delivery, insertion time, immediate outcome, inpatient complications, success of mobilisation of the patient at one and two hours after the procedure, and whether these variables relate to individual patient characteristics. RESULTS--Successful placement of the device was achieved in 57 of 63 consecutive patients (90.5%). The mean (SD) insertion time was 86 (24) seconds. Six (9.5%) patients did not receive the haemostat because of femoral artery perforation by the tissue dilator (n = 3), inability to compress the femoral artery proximal to the site of delivery (n = 1), pre-existing haematoma (n = 1), or patient withdrawal from the study (n = 1). Uncomplicated mobilisation within two hours of investigation was possible in 54 of 57 (94.7%) patients receiving this device. A sizeable haematoma (> 5 x 5 cm) prevented early mobilisation in the remaining three patients. Mobilisation was uncomplicated in 32 of 34 (94.1%) patients mobilised at two hours and 22 of 23 (95.6%) at one hour (NS). One patient who was mobilised early without complication later developed evidence of claudication in the treated leg. Femoral arteriography showed a smooth intraluminal filling defect attached to the wall of the femoral artery at the puncture site. This obstruction, presumed to be a collagen plug, was treated successfully with angioplasty. Sheath size, arterial pressure, the use of aspirin, heparin or warfarin, and body mass index did not influence patient outcome. The pattern of complications did not relate to a learning curve experience. CONCLUSIONS--The bovine collagen haemostat is a relatively safe and effective device that allows far earlier patient mobilisation than conventional haemostasis after diagnostic and therapeutic interventions from a percutaneous femoral artery approach. These results have important implications for patients undergoing investigation in mobile x ray units or in hospital based day case units. 相似文献
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Relative carriage rates of nuclear dehydrogenating clostridia in two populations of different colorectal cancer risk
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Carriage of nuclear dehydrogenating clostridia has been associated with colon cancer and implicated in its aetiology. This study has compared the carriage of these organisms in a British population at high risk for the development of colon cancer with a low risk Nigerian population. Clostridia were found in all of the stools from both populations. Nuclear dehydrogenating clostridia were only found in the stools of the British subjects (32%). These results support the suggestion that the carriage rate of nuclear dehydrogenating clostridia in a population is related to the risk of colon cancer. 相似文献
7.
The locus of enterocyte effacement (LEE)-encoded regulator controls expression of both LEE- and non-LEE-encoded virulence factors in enteropathogenic and enterohemorrhagic Escherichia coli 总被引:7,自引:0,他引:7
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Elliott SJ Sperandio V Girón JA Shin S Mellies JL Wainwright L Hutcheson SW McDaniel TK Kaper JB 《Infection and immunity》2000,68(11):6115-6126
Regulation of virulence gene expression in enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) is incompletely understood. In EPEC, the plasmid-encoded regulator Per is required for maximal expression of proteins encoded on the locus of enterocyte effacement (LEE), and a LEE-encoded regulator (Ler) is part of the Per-mediated regulatory cascade upregulating the LEE2, LEE3, and LEE4 promoters. We now report that Ler is essential for the expression of multiple LEE-located genes in both EPEC and EHEC, including those encoding the type III secretion pathway, the secreted Esp proteins, Tir, and intimin. Ler is therefore central to the process of attaching and effacing (AE) lesion formation. Ler also regulates the expression of LEE-located genes not required for AE-lesion formation, including rorf2, orf10, rorf10, orf19, and espF, indicating that Ler regulates additional virulence properties. In addition, Ler regulates the expression of proteins encoded outside the LEE that are not essential for AE lesion formation, including TagA in EHEC and EspC in EPEC. delta ler mutants of both EPEC and EHEC show altered adherence to epithelial cells and express novel fimbriae. Ler is therefore a global regulator of virulence gene expression in EPEC and EHEC. 相似文献
8.
Development of hatching blastocysts from immature human oocytes following in-vitro maturation and fertilization using a co-culture system 总被引:8,自引:0,他引:8
Hwu YM; Lee RK; Chen CP; Su JT; Chen YW; Lin SP 《Human reproduction (Oxford, England)》1998,13(7):1916-1921
Recently, in-vitro maturation (IVM) of immature human oocytes recovered
from non-stimulated follicles has been applied in the treatment of
infertility. However, in previous reports, very few embryos cultured in
conventional medium have reached the expanded blastocyst stage following
in-vitro maturation and fertilization (IVM/IVF). The objective of this
study was to investigate whether the developmental competence of human
embryos following IVM/IVF could be enhanced by the use of a human ampullary
cell co-culture system. Immature human oocytes were aspirated from small
follicles at Caesarean section and then cultured in medium containing human
menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes
were randomly cultured either in conventional culture medium alone or in
the co-culture system. Of 48 embryos cultured in conventional medium alone,
all arrested at the 2-16- cell stage on day 3 after insemination. Of 46
embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at
the 2-16-cell stage. Six embryos (13%) developed to the morula stage.
Fourteen embryos (30.4%) developed to expanded blastocysts and two
blastocysts were hatching on day 7 after insemination. We conclude that
co-culture significantly enhances the development of blastocysts in embryos
resulting from IVM/IVF.
相似文献
9.
M Farrall P Scambler K W Klinger K Davies C Worrall R Williamson B Wainwright 《Journal of medical genetics》1986,23(4):295-299
Cloned DNA markers which are closely linked to the gene defect causing cystic fibrosis have recently been described. These markers are sufficiently informative for carrier detection in 80% of families where there is a living cystic fibrosis child and unaffected sibs. The tightly linked DNA marker pJ3.11 was used in this study to identify carriers in six families and exclude carrier status in two subjects. Risk calculations for recessive diseases using linked DNA probes may be complex, but useful information for counselling can be obtained in this way. 相似文献
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