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排序方式: 共有539条查询结果,搜索用时 15 毫秒
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Grazyna Perko Jes F. Schmidt Jorgen Warberg Niels H. Secher 《European journal of applied physiology》1996,73(5):459-464
To evaluate influences on blood volume distribution, atrial natriuretic peptide concentrations (ANP) and thoracic and leg electrical impedance at 2.5 (TI2.5 and LI2.5, respectively) and 100 kHz (TI100 and LI100, respectively) were monitored during administration of ketanserin, noradrenaline and trimetaphan combined with lower body negative pressure (LBNP) in 12 subjects. Administration of clinically relevant doses of ketanserin alone did not induce changes in mean arterial pressure (MAP) or in the central blood volume, as electrical impedance and ANP concentrations did not change. During continued infusion of ketanserin an increase in MAP from a mean of 90 (range 83–108) to 113 (range 98–138) mmHg was induced by noradrenaline, but TI2.5 [mean 45.6 (range 39.3–54.2)] and TI100 [mean 33.8 (range 27.5–38.5) ] remainded stable until ganglionic blockade and LBNP were applied, when they increased by a mean of 3.1 (range 2.0–6.1) and 2.7 (range 1.1–4.2) , respectively (P < 0.05). Conversely, LI2.5 [mean 79.6 (range 74.1–89.4)] and LI100 [mean 56.7 (range 52.4–63.3) ] decreased by a mean of 3.2 (range 1.2–8.0) and 2.3 (range 0.9–3.9) ANP from a mean of 27.7 (range 10.2–62.7) to 12.7 (range 7.1–27.5) pmol· 1–1 and MAP fell to a mean of 62 (range 42–70) mmHg (P < 0.05). The heart rate was a mean of 75 (range 69–77) beats -min-' and did not change until LBNP, when it increased to a mean of 102 (range 78–104) beats · min–1, as presyncopal symptoms appeared. The data indicated that serotonergic blockade by ketanserin and -sympathetic stimulation by noradrenaline did not affect blood volume distribution in normal humans, but that ganglionic blockade combined with LBNP reduced the central blood volume as leg volume increased; during central hypovolaemia tachycardia induced by ganglionic blockade did not prevent the fall in MAP, and thereby the appearance of presyncopal symptoms. 相似文献
3.
The major problem of detecting reaginic antibody by passive cutaneous anaphylaxis IPCA) is the quantitation of the dye reaction. Radiolabelled antigen was used in an attempt to quantitate the PCA reaction (Radio-PCA). Antisera containing reaginic antibody against human serum albumin (HSA) were produced in rabbits. These antisera were injected into normal rabbit skin in different dilutions. Twenty-four hours later BSA was injected intravenously either with Evans Blue or as 125-1-HSA. Radioactivity found in antibody-containing skin was significantly higher than in control specimens containing saline or normal rabbit serum, as low as antiserum dilutions of 1:1,000. Compared with the Evans Blue technique Radio-PCA was able to distinguish quantitatively between different antiserum dilutions at a higher level of statistical significance. 相似文献
4.
Armoundas AA Ju K Iyengar N Kanters JK Saul PJ Cohen RJ Chon KH 《Annals of biomedical engineering》2002,30(2):192-201
Current methods for detecting nonlinear determinism in a time series require long and stationary data records, as most of them assume that the observed dynamics arise only from the internal, deterministic workings of the system, and the stochastic portion of the signal (the noise component) is assumed to be negligible. To explicitly account for the stochastic portion of the data we recently developed a method based on a stochastic nonlinear autoregressive (SNAR) algorithm. The method iteratively estimates nonlinear autoregressive models for both the deterministic and stochastic portions of the signal. Subsequently, the Lyapunov exponents (LE) are calculated for the estimated models in order to examine if nonlinear determinism is present in the deterministic portion of the fitted model. To determine if nonlinear dynamic analysis of heart-rate fluctuations can be used to assess arrhythmia susceptibility by predicting the outcome of invasive cardiac electrophysiologic study (EPS), we applied the SNAR algorithm to noninvasively measured resting sinus-rhythm heart-rate signals obtained from 16 patients. Our analysis revealed that a positive LE was highly correlated to a patient with a positive outcome of EPS. We found that the statistical accuracy of the SNAR algorithm in predicting the outcome of EPS was 88% (sensitivity=100%, specificity=75%, positive predictive value=80%, negative predictive value=100%, p=0.0019). Our results suggest that the SNAR algorithm may serve as a noninvasive probe for screening high-risk populations for malignant cardiac arrhythmias. © 2002 Biomedical Engineering Society.
PAC2002: 8719Hh, 0545Tp, 8710+e 相似文献
5.
目的 观察Intralipid对内毒素所致的多形核白细胞氧自由基产生的影响,方法 取22例健康志愿者静脉血,采用Boyum法提取多核白细胞(PMN)并在体外培养,采用不同剂量的脂多糖(LPS)刺激PMN,并和不同剂量Intralipid共同作用,采用NBT还原剂试验测定氧自由基的产生量。结果 LPS刺激各组的NBT值明显高于非刺激组,而且NBT值与LPS浓度明显相关,Intralipid可明显浓度 相似文献
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Lydie Canier Nimol Khim Saorin Kim Rotha Eam Chanra Khean Kaknika Loch Malen Ken Pieter Pannus Philippe Bosman Jorgen Stassijns Fabienne Nackers SweetC Alipon Meng Chuor Char Nguon Chea William Etienne Martin De Smet Jean-Marie Kindermans Didier Ménard 《The American journal of tropical medicine and hygiene》2015,92(3):573-577
In the context of malaria elimination, novel strategies for detecting very low malaria parasite densities in asymptomatic individuals are needed. One of the major limitations of the malaria parasite detection methods is the volume of blood samples being analyzed. The objective of the study was to compare the diagnostic accuracy of a malaria polymerase chain reaction assay, from dried blood spots (DBS, 5 μL) and different volumes of venous blood (50 μL, 200 μL, and 1 mL). The limit of detection of the polymerase chain reaction assay, using calibrated Plasmodium falciparum blood dilutions, showed that venous blood samples (50 μL, 200 μL, 1 mL) combined with Qiagen extraction methods gave a similar threshold of 100 parasites/mL, ∼100-fold lower than 5 μL DBS/Instagene method. On a set of 521 field samples, collected in two different transmission areas in northern Cambodia, no significant difference in the proportion of parasite carriers, regardless of the methods used was found. The 5 μL DBS method missed 27% of the samples detected by the 1 mL venous blood method, but most of the missed parasites carriers were infected by Plasmodium vivax (84%). The remaining missed P. falciparum parasite carriers (N = 3) were only detected in high-transmission areas. 相似文献
8.
9.
Summary The relation between urinary albumin excretion rate (UAE), transcapillary escape rate of albumin (TERalb), haemostatic factors, ambulatory blood pressure, and metabolic variables was investigated in 45 Type II (non-insulin-dependent)
diabetic patients without overt nephropathy or uncontrolled blood pressure. We enrolled 44 patients in a placebo controlled
study to test the effects of 3 week long treatment with low-molecular weight heparin (tinzaparin) on the same variables. BMI,
24 h systolic and diastolic blood pressure, plasma concentrations of triglycerides, fasting glucose, factor VIII, von Willebrand
factor (vWf), fibrinogen, α-2 macroglobulin, and fibronectin were notably higher in patients with increased albuminuria compared
with normoalbuminuric patients, whereas the TERalb was similar in the two groups. TERalb correlated with fasting plasma glucose. UAE correlated more closely than TERalb with 24 h ambulatory blood pressure, vWf, and factor VIII. Urinary albumin excretion rate was unchanged during tinzaparin
[28.9 ± 5.6 vs 28.1 ± 6.0 μg/min (geometric mean (antilog SD)] vs placebo (18.0 ± 5.4 vs 17.6 ± 5.3 μg/min), and no change
was found in TERalb [6.3 ± 1.6 vs 6.0 ± 1.5 %/h (means ± SD), and 6.3 ± 1.5 vs 5.6 ± 1.8 %/h; tinzaparin versus placebo, respectively]. Only
minor changes were observed in blood pressure, lipids, glycaemic control and haemostatic factors. This study shows no correlation
between albuminuria and transcapillary escape rate in Type II diabetic patients without overt nephropathy or uncontrolled
blood pressure. UAE is related to markers of atherosclerosis, endothelial injury and dysfunction, and haemostatic factors.
Moreover, UAE correlates much more than TERalb with 24 h ambulatory blood pressure, von Willebrand factor, and factor VIII. Finally, short-term treatment with tinzaparin
does not change the transvascular or glomerular leakage of albumin. These results indicate that TERalb is not a sensitive marker of microvascular dysfunction in such patients and that factors other than abnormal glycosaminoglycan
metabolism may contribute to the vascular damage of these patients. [Diabetalogia (1999) 42: 60–67]
Received: 2 February 1998 and in final revised form: 1 September 1998 相似文献
10.
Rahul Damodaran Prabha David Christian Evar Kraft Linda Harkness Birte Melsen Harikrishna Varma Prabha D. Nair Jorgen Kjems Moustapha Kassem 《Journal of tissue engineering and regenerative medicine》2018,12(3):e1537-e1548
There has been a growing demand for bone grafts for correction of bone defects in complicated fractures or tumours in the craniofacial region. Soft flexible membrane like material that could be inserted into defect by less invasive approaches; promote osteoconductivity and act as a barrier to soft tissue in growth while promoting bone formation is an attractive option for this region. Electrospinning has recently emerged as one of the most promising techniques for fabrication of extracellular matrix such as nano‐fibrous scaffolds that can serve as a template for bone formation. To overcome the limitation of cell penetration of electrospun scaffolds and improve on its osteoconductive nature, in this study, we fabricated a novel electrospun composite scaffold of polyvinyl alcohol (PVA)‐poly (ε) caprolactone (PCL)‐Hydroxyapatite based bioceramic (HAB), namely, PVA‐PCL‐HAB. The scaffold prepared by dual electrospinning of PVA and PCL with HAB overcomes reduced cell attachment associated with hydrophobic PCL by combination with a hydrophilic PVA and the HAB can contribute to enhance osteoconductivity. We characterized the physicochemical and biocompatibility properties of the new scaffold material. Our results indicate PVA‐PCL‐HAB scaffolds support attachment and growth of stromal stem cells; [human bone marrow skeletal (mesenchymal) stem cells and dental pulp stem cells]. In addition, the scaffold supported in vitro osteogenic differentiation and in vivo vascularized bone formation. Thus, PVA‐PCL‐HAB scaffold is a suitable potential material for therapeutic bone regeneration in dentistry and orthopaedics. 相似文献