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101.
In this study the local vasoactive effects of adenosine were explored in the human forearm. Adenosine (15 micrograms/100 ml forearm/min) infused into the brachial artery (n = 6) increased forearm blood flow by 572% +/- 140%, versus - 0.5% +/- 5.8% during placebo infusion (p less than 0.01). Lower adenosine infusion rates (5 micrograms/100 ml forearm/min, three times) induced forearm blood flow increments to 330% +/- 94%, 339% +/- 67% and 330% +/- 79%, respectively (n = 8). These forearm blood flow responses were reduced (p = 0.02) during concomitant intra-arterial infusion of two doses of caffeine (30 and 90 micrograms/100 ml forearm/min) to 150% +/- 45% and 98% +/- 28%, respectively. Theophylline (30 micrograms/100 ml forearm/min; n = 6) also significantly attenuated the adenosine-induced increase in forearm blood flow. Enprofylline (30 micrograms/100 ml forearm/min), a related xanthine with a low affinity to adenosine receptors in vitro, did not change the response to adenosine. Nonspecific vasodilation by sodium nitroprusside infusion (50 ng/100 ml forearm/min) was not inhibited by caffeine compared with placebo (forearm blood flow responses were 202% +/- 21% versus 216% +/- 40%; n = 6). This study demonstrated that caffeine and theophylline specifically reduce adenosine-induced vasodilation in humans, supporting the existence of functional human vascular adenosine receptors. 相似文献
102.
Junfang Deng Ryan N Ptashkin Yu Chen Zhi Cheng Guangliang Liu Thien Phan Xiaoling Deng Jiehua Zhou Inhan Lee Yong Sun Lee Xiaoyong Bao 《Molecular therapy》2015,23(10):1622-1629
Target identification is highly instructive in defining the biological roles of microRNAs. However, little is known about other small noncoding RNAs; for example, tRNA-derived RNA Fragments (tRFs). Some tRFs exhibit a gene-silencing mechanism distinctly different from that of typical microRNAs. We recently demonstrated that a respiratory syncytial virus (RSV)-induced tRF, called tRF5-GluCTC, promotes RSV replication. RSV is the single most important cause of lower respiratory tract infection in children. By using biochemical screening and bioinformatics analyses, we have identified apolipoprotein E receptor 2 (APOER2) as a target of tRF5-GluCTC. The 3′-portion of tRF5-GluCTC recognizes a target site in the 3′-untranslated region of APOER2 and suppresses its expression. We have also discovered that APOER2 is an anti-RSV protein whose suppression by tRF5-GluCTC promotes RSV replication. Our report represents the first identification of a natural target of a tRF and illustrates how a virus utilizes a host tRF to control a host gene to favor its replication. 相似文献
103.
104.
Loan HT Parry J Nga NT Yen LM Binh NT Thuy TT Duong NM Campbell JI Thwaites L Farrar JJ Parry CM 《Transactions of the Royal Society of Tropical Medicine and Hygiene》2012,106(2):90-97
Healthcare-associated pneumonia (HCAP) is a common complication in patients with severe tetanus. Nursing tetanus patients in a semi-recumbent body position could reduce the incidence of HCAP. In a randomised controlled trial we compared the occurrence of HCAP in patients with severe tetanus nursed in a semi-recumbent (30°) or supine position. A total of 229 adults and children (aged ≥1 year) with severe tetanus admitted to hospital in Vietnam, were randomly assigned to a supine (n=112) or semi-recumbent (n=117) position. For patients maintaining their assigned positions and in hospital for>48h there was no significant difference between the two groups in the frequency of clinically suspected pneumonia [22/106 (20.8%) vs 26/104 (25.0%); p=0.464], pneumonia rate/1000 intensive care unit days (13.9 vs 14.6; p=0.48) and pneumonia rate/1000 ventilated days (39.2 vs 38.1; p=0.72). Mortality in the supine patients was 11/112 (9.8%) compared with 17/117 (14.5%) in the semi-recumbent patients (p=0.277). The overall complication rate [57/112 (50.9%) vs 76/117 (65.0%); p=0.03] and need for tracheostomy [51/112 (45.5%) vs 69/117 (58.9%); p=0.04) was greater in semi-recumbent patients. Semi-recumbent body positioning did not prevent the occurrence of HCAP in severe tetanus patients. 相似文献
105.
C M Smith P E Christie R J Hawksworth F Thien T H Lee 《The American review of respiratory disease》1991,144(6):1411-1413
Urinary leukotriene E4 (LTE4) concentrations were measured in six asthmatic subjects after treadmill exercise, and in five asthmatic subjects after allergen challenge. Exercise and allergen challenge produced a 42 +/- 18% (mean +/- SD) and 22 +/- 8% fall in FEV1, respectively. The baseline concentration of urinary LTE4 in subjects challenged with exercise was 64 (27 to 150) pg/mg creatinine (geometric mean and 95% confidence interval), and in those challenged with allergen it was 36 (23 to 59) pg/mg creatinine. Urinary LTE4 concentrations did not change significantly in the 24 h after exercise. In contrast, there was a mean 4-fold increase in urinary LTE4 during the 3 h after allergen challenge. 相似文献
106.
In a double-blind placebo-controlled study, we examined the effect of caffeine pretreatment on the haemodynamic and humoral changes after a standardized breakfast in 15 healthy elderly subjects (mean age 75.4 +/- 6.6 years). After placebo, the preprandial blood pressure did not change and the postprandial blood pressure declined by a maximum of 6.1%. After oral ingestion of 250 mg caffeine, 60 min before breakfast, the preprandial blood pressure increased by 12.5%. Although the decrease of the postprandial blood pressure was not altered, blood pressure remained above its basal value. The increase in plasma noradrenaline after the meal was similar in the placebo and the caffeine tests. Plasma adrenaline decreased after placebo (-19%) but did not change after caffeine. Thus, despite the unchanged decrease of the postprandial blood pressure, the preprandial pressor effect of caffeine prevented the decline of the postprandial blood pressure below its baseline value. The clinical relevance of this finding has still to be determined. 相似文献
107.
The accuracy of the Welch Allyn Vital Signs Monitor, a compact device for the oscillometric measurement of blood pressure, was determined according to the British Hypertension Society protocol. The monitor achieved a grade C for diastolic and a grade D for systolic blood pressure. The device is suitable for monitoring a patient, for example post-operatively, in the emergency department or during an intervention. The device cannot, however, be recommended for an exact determination of blood pressure when compared with the mercury sphygmomanometer. In an earlier validation report, the Welch Allyn Vital Signs Monitor achieved a grade A for both diastolic and systolic blood pressure. After adjusting for the difference in method of calculating the grades used in the two studies, there remained a considerable difference in grading results, for which no clear reason could be found. 相似文献
108.
Ronday HK; Te Koppele JM; Greenwald RA; Moak SA; De Roos JA; Dijkmans BA; Breedveld FC; Verheijen JH 《Rheumatology (Oxford, England)》1998,37(1):34-38
The plasminogen activation system is one of the enzyme systems held
responsible for bone and cartilage degradation in rheumatoid arthritis
(RA). In this study, we evaluated the effect of tranexamic acid (TEA), an
inhibitor of plasminogen activation, on urinary collagen cross-link
excretion and radiological joint damage in rat adjuvant arthritis (AA) and
on urinary collagen cross-link excretion in patients with RA. In the animal
study, adjuvant arthritis was induced in male Lewis rats. From day 7
onward, high-dose TEA (500 mg/kg body weight, once daily) or placebo was
administered orally. Study groups consisted of TEA-treated normal rats (C +
TEA), placebo-treated normal rats (C + plac), AA rats treated with TEA (AA
+ TEA) or with placebo (AA + plac). To monitor joint destruction, urinary
collagen cross-link excretion (pyridinoline, HP; deoxypyridinoline, LP) was
measured by high-performance liquid chromatography at days 14 and 21.
Radiological evaluation of joints was performed at day 21. In the patient
study, TEA was administered to nine patients with RA as adjuvant medication
(approximately 20 mg/kg body weight, three times daily) for 12 weeks.
Urinary HP and LP excretion levels were measured before and during TEA
treatment, and 4 weeks after the cessation of TEA treatment. In AA + TEA
rats, a significant reduction of HP and a tendency towards a reduction of
LP excretion were found compared with AA + plac rats (P < 0.05), at day
14, whereas the HP/LP ratio did not change. No difference was observed in
HP, LP excretion, HP/LP ratio and radiological damage score between the
TEA- and placebo-treated AA rats at day 21. In RA patients, a significant
reduction of HP and LP excretion was found during the TEA treatment period
(P < 0.05). After the cessation of TEA treatment, HP and LP excretion
increased towards baseline levels. No effect on disease activity was
observed. The plasmin antagonist TEA reduced the excretion of collagen
pyridinoline cross-links in both experimental and rheumatoid arthritis. As
such, this study not only supports the involvement of the plasminogen
activation system in the destructive phase of arthritis, but also suggests
a beneficial effect of therapeutic strategies directed against inhibition
of matrix proteolysis.
相似文献
109.
R W Jansen J W Lenders T Thien W H Hoefnagels 《Journal of the American Geriatrics Society》1989,37(6):528-532
It has been reported that postural hypotension in the elderly is common. However, these studies included institutionalized and more or less disabled persons. Furthermore, postural hypotension may be related to baseline blood pressure. In this study, the influence of age and blood pressure on the hemodynamic and plasma catecholamine responses to orthostatic stress was investigated in young and old normotensive and hypertensive healthy subjects. In normotensive and hypertensive elderly persons, the percentage blood pressure responses during tilt were not significantly different from that seen in young normotensives. We measured a slight decrease of systolic blood pressure and a slight increase of diastolic blood pressure. The hypertensive young patients showed an enhanced diastolic blood pressure response with no fall in systolic blood pressure, in contrast to the normotensive young subjects. Both elderly groups had a lower increase of heart rate than the young subjects. The percentage increase in norepinephrine after tilting was significantly lower in elderly hypertensives than in elderly normotensives and young hypertensives. The presence of hypertension was associated with a decrease in blood pressure, but age had no influence on the change in blood pressure during tilt. In this group of healthy elderly subjects, there was no significant orthostatic hypotension when the blood pressure course of the entire tilt test was taken into account. 相似文献
110.
Heterotypic adherence between marrow stromal cells (MSC) and lymphoblastic cells is essential for normal lymphopoiesis and malignant lymphoblastic development. However, the detailed molecular mechanisms by which this heterotypic adherence occurs are poorly understood. The cell-cell interactions between a B-lymphoblastic cell line (UTMB-460) and a pre-B-cell line (NALM-6) with MSC were chosen as models to investigate potential mechanisms and adhesion molecules involved in the apposition between normal and malignant lymphoblastic cells and MSC. A parallel-flow detachment assay (PFDA) and a 51Cr detachment assay, coupled with monoclonal antibody (MoAb) blocking experiments, were used to quantify the attachment of lymphoblastic cells to confluent monolayers of MSC. The apposition between MSC and B-lymphoblastic cells (UTMB-460 cells) was investigated for variable time periods, ranging from 1 minute to 4 hours. Results from the temporal study suggest that the heterotypic adherence of the B-lymphoblastic cells to MSC is a biphasic event and the interactions occur rapidly (< or = 1 minute) after the two cells come into contact. More specifically, the early phase of adherence (< or = 15 minutes) solely involves very late antigen-4 alpha (VLA-4 alpha)/vascular cell adhesion molecule 1 (VCAM- 1) interactions, as evidenced by the nearly complete inhibition (93%) of UTMB-460 cell adherence in the presence of anti-VLA-4 alpha. The late phase (> or = 30 minutes) proceeds despite the continuous presence of anti-VLA-4 alpha. In addition, the late-phase adherence is not affected by MoAbs to LFA-1, CD44, VCAM-1, E-selectin, or L-selectin, which suggests the possible involvement of other adhesion molecules. Adherence of pre-B-lymphoblastic cells (NALM-6) to MSC is also biphasic. Integrin VLA-4 is again a major player in the early phase of pre-B-lymphoblastic cell/MSC interactions. The early phase of adherence may be important in homing of the malignant lymphoblastic cells to the MSC and the late phase in retention of malignant lymphoblastic cells in the bone marrow. 相似文献