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Summary The effects of changes in endogenous endothelium-derived nitric oxide (NO) on forearm blood flow and ex vivo platelet aggregation have been studied in 7 healthy volunteers.Measurements were made of forearm blood flow and ex vivo collagen-stimulated platelet aggregation during unilateral brachial artery infusions of saline, acetylcholine (ACh), NG monomethyl-L-arginine (L-NMMA), and prostacyclin (PGI2). The uninfused arm acted as a control.Forearm blood flow was increased by ACh, an agent which stimulates NO release, and decreased by L-NMMA, an agent which stereospecifically inhibits NO synthesis.Collagen-stimulated platelet aggregation measured ex vivo in whole blood draining the infused arm was unaltered by either ACh or L-NMMA. Conversely, PGI2, an agent which acts independently of NO, caused an increase in forearm blood flow which was accompanied by significant inhibition of platelet aggregation.The results suggest that release of endothelium-derived NO in quantities sufficient to cause substantial changes in blood vessel tone does not lead to changes in platelet aggregation in the blood flowing through the vessels. It is, however, still possible that endothelium-derived NO modulates platelet activity at the level of the endothelium.
Present address: Department of Medicine and Therapeutics, University of Aberdeen Polwarth Building, Forrester Hill, Aberdeen, UK 相似文献
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Parental and professional responses to questionnaires evaluating a paediatric disability service are reported and the viability of auditing structural, process, and outcome aspects of clinical practice are discussed. Expectations of waiting time to first appointment (met for only 52% of consumers) illustrate structural issues. Process issues are reflected in consumer reactions to outreach work (for example, 94% of parents and 84% of professionals found this supportive). Outcome measures such as consumer satisfaction with the service (76% of consumers reported being 'very satisfied' and 20% 'fairly satisfied') suggest that service aims are being met. Good concurrence of service aims with consumer needs is indicated by parental reasons for referral (for example, 75% for diagnostic help, 73% for a better understanding of the disorder, 88% for practical help), referrers' reasons (for example, 55% for a second diagnostic opinion, 45% due to lack of local expertise), and reports from most other professionals involved with the case that a similar service was not provided locally. 相似文献
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Bilateral simultaneous tubal sextuplets: pregnancy after in-vitro fertilization--embryo transfer following salpingectomy 总被引:2,自引:1,他引:2
The presence of a damaged tube has been suggested in recent studies to have
a negative effect on in-vitro fertilization (IVF) outcome. Performing
bilateral salpingectomy prior to IVF to maximize pregnancy rates may also
result in unnecessary surgery. This case is also an example of the
occurrence of interstitial pregnancy after salpingectomy. This unusual type
of ectopic pregnancy must be kept in mind when evaluating a patient
suspected of a possible early abnormal gestation after assisted
reproductive technolologies.
相似文献
7.
The impact of hydrosalpinx (HSPX) on in-vitro fertilization (IVF) outcome
has recently been the subject of intense debate. Most, but not all, studies
have reported decreased implantation and pregnancy rates and increased
early pregnancy loss in HSPX patients. This has led to prophylactic
salpingectomies prior to IVF in HSPX patients despite the lack of any
prospective studies to suggest that any improvement will occur. Women with
HSPX constitute a heterogeneous population because some conceive easily
with IVF while others do not until after surgical correction. HSPX also
increases in size with ovarian stimulation, and can cause implantation
failure by fluid reflux into the uterine cavity. Careful assessment of the
endometrial lining is mandatory in HSPX to rule out fluid reflux from the
HSPX. We present two case reports of patients whose HSPX enlarged with
ovarian stimulation, causing fluid reflux into the uterine cavity which was
only noted after human chorionic gonadotrophin (HCG) administration.
相似文献
8.
White RP Deane C Hindley C Bloomfield PM Cunningham VJ Vallance P Brooks DJ Markus HS 《Journal of the neurological sciences》2000,178(1):23-28
Despite their potential use as cerebral vasodilatory agents there are few studies of the effect of nitric oxide (NO) donors on the cerebral circulation in non-anaesthetised man. We determined the effect of the NO donor glyceryl trinitrate (GTN) at clinically relevant doses on global and regional cerebral blood flow (CBF) in healthy non-anaesthetised volunteers, using H(2)(15)O PET, ultrasonic colour velocity flow imaging of carotid artery flow, and transcranial Doppler (TCD) of middle cerebral artery velocities (MCAv). Three rates of GTN infusion (0.1, 0.4, 1.0 microg/kg/min) were used. There was no significant change in common or internal carotid artery flow following GTN administration although a dose dependent fall in MCAv post GTN was observed. There was no significant change in either global or regional CBF following GTN. Thus intravenous GTN at therapeutic doses in awake humans does not alter global or regional CBF. However it does produce basal cerebral artery vasodilatation as evidenced by a fall in MCAv in the absence of a change in internal carotid artery flow. 相似文献
9.
Lauren Desrosiers Sarah Scollon Rebecca Littlejohn Kimberly Nugent Rebecca Althaus Jessica Corredor Emily Berenson Rachel Wyatt Timothy Griffin Kelly Vallance Jonathan Gill Gail Tomlinson Juan Carlos Bernini Angshumoy Roy George Miles Jacquelyn Reuther Shashikant Kulkarni Christine Eng Sharon Plon 《Molecular genetics and metabolism》2021
10.
The development of peroxidase (PO) reaction in the nuclear envelope (NE) and endoplasmic reticulum (ER) of monocytes differentiating in vitro and its relationship with arachidonic acid metabolism were studied. The PO, as visualized by the diaminobenzidine (DAB) technique, appeared in the NE and ER of the majority of monocytes within 24 hours of culture, with a substantial decrease thereafter. The influence of three major groups of agents--inhibitors of PO, of prostanoids, and of protein biosynthesis--upon the development of the PO reaction was examined. When aminotriazole, a PO inhibitor, was added to the culture medium, the appearance of PO was suppressed in the monocytes. The cyclooxygenase blocker, indomethacin, however, did not influence the development of PO. Also the blockers of protein synthesis, puromycin, cycloheximide, and actinomycin D, did not affect the appearance of PO. The prostanoids released from the monocytes, ie, prostaglandin E and thromboxane B2, were determined by radioimmunoassay and showed a time sequence of secretion that corresponded to the appearance of PO in the cells: a marked increase within the first 24 hours with a substantial decrease thereafter. The presence of the PO inhibitors aminotriazole and sodium azide in the culture medium produced a suppression of prostanoid release from the monocytes comparable with that of indomethacin. The data suggest that the PO in the NE and ER of differentiating monocytes in vitro (1) is associated with arachidonic acid metabolism, and (2) is not formed by de novo protein synthesis but rather by an activation process. 相似文献