去除白细胞输血的临床意义

目的:评估去除白细胞输血的临床应用价值。方法:251例患者接受了去除白细胞红细胞悬液761U,(每人1￣8U不等),对其中200U红细胞悬液滤除白细胞前、后分别进行白细胞计数和血红蛋白测定,并对其输血反应进行了观察。结果:发现应用白细胞滤器后,其白细胞数比过滤前显著减低,过滤前、后白细胞数分别为(6.16±1.44)×109/L与(0.12±0.10)×109/L(P<0.01),血红蛋白过滤前、后无显著性差异,分别为:(161.58±23.31)g/L与(157.84±22.35)g/L,P>0.05。251例接受去白细胞受血者均未出现输血反应。结论:白细胞滤器能有效去除白细胞,去除白细胞能减少非溶血性输血反应。     

The current role of preoperative and intraoperative autologous blood donation in pediatric open-heart surgery

Objective: We assessed the current role of preoperative and intraoperative autologous blood donation in pediatric open-heart surgery. Methods: Group 1 consisted of 51 patients between 5 and 10 years old who underwent preoperative autologous blood donation. Group 2 consisted of 50 age-matched patients without preoperative donation as controls. Intraoperative donation was conducted in both groups prior to cardiopulmonary bypass. We evaluated perioperative blood cell count, blood loss, and the need for homologous blood products. Results: No serious complications occurred in preoperative or intraoperative donation. Total preoperative donation storage was 17.5±3.4 mL/kg. Intraoperative donation was 21.7 ±6.1 mL/kg in Group 1 and 12.8±4.0 mL/kg in Group 2 (p<0.001). On admission, serum hemoglobin was lower in Group 1 (12.2±1.0 g/dL versus 13.6±1.6 g/dL, p<0.001) but returned postoperatively to the preoperative value. It hovered at a depressed level in Group 2 (12.2±1.4 versus 10.2±1.1 g/dL, p<0.001). The homologous blood requirement was significantly less in Group 1 than in Group 2 (0% versus 10%, p<0.05). Postoperative platelet counts showed similar curves, and blood loss was not statistically significantly different between groups. Conclusion: Preoperative and intraoperative donations are safe and continue to contribute uniquely to blood conservation, providing important options in comprehensive blood conservation programs in current pediatric open-heart surgery.     

血细胞彩色图像的微机自动计数方法探讨

目的　探讨血细胞自动计数的方法。方法　采用微机彩色图像处理技术对血液细胞图像进行图像分割和细胞计数。结果　与人工计数相平行 ,相关系数r =0 .96 1～ 0 .997,P >0 .0 5。结论　该方法可行且计数相对精确、迅速、客观     

计算法测定肾小球滤过率的临床应用价值

目的 :探讨采用 WCP公式计算方法测定肾小球滤过率 (GFR)的临床应用价值。方法 :采用 99m Tc DTPA清除率测定 6 6例不同疾病住院患者 GFR(Tc GFR) ,并测血清肌酐 (SCr)及尿素氮 (BU N) ,同时以 WCP公式、Robert公式计算 GFR(WCP GFR,Robert GFR) ,以 Cockcroft/ Gault公式计算内生肌酐清除率 (CG CCr) ,所得数据进行对比研究及相关性分析。结果 :除肾功能正常者 CG CCr与 BU N无显著相关外 ,肾功能不全及肾功能正常者的 WCP GFR、Robert GFR、CG CCr均分别与 Tc GFR呈显著正相关(P均 <0 .0 1) ,与 BU N、SCr呈显著负相关 (P<0 .0 1或 P<0 .0 5 ) ;与 Robert GFR、CG CCr比较 ,WCPGFR始终与 Tc GFR最接近 (P均 >0 .0 5 ) ;WCP GFR、Robert GFR、CG CCr与 Tc GFR的平均差绝对值逐渐增大 ,三者间差异显著 (P均 <0 .0 5 )。结论 :WCP GFR、Robert GFR、CG CCr均能在一定程度上准确反映 GFR,而以 WCP GFR更准确 ,且简便、快速、安全而廉价 ,可代替 Tc GFR应用于临床     

Signal-to-noise ratio effects in quantitative cerebral perfusion using dynamic susceptibility contrast agents.

Theoretical and simulation evidence is presented in support of the idea that the optimal manner of determining blood flow from MR perfusion studies is not necessarily obtained by setting experimental conditions to maximize either the arterial input or the measured tissue concentration level for a particular echo time (TE). The noise power in the contrast concentration curve is associated with its peak because of the nonlinear relationship between the contrast concentration and MR signal intensity curves. The optimum signal-to-noise ratio (SNR), SNR(C), for a particular contrast concentration curve can be obtained when the experimental concentration level and TE are adjusted to produce an MR intensity curve whose signal loss is 63% of the precontrast MR signal intensity. It is demonstrated that the stability of the singular valued decomposition (SVD) deconvolution approach to determine blood flow parameters is increased when the tissue curve maximum signal loss is in the range of 40-80%. The accuracy and stability of the SVD-determined blood flow parameters are affected by deviations from these optimum conditions in a manner that depends on the mean transit time (MTT) associated with the residue function. It is recommended that the experimental TE value be set so that neither the tissue nor the arterial curves are placed a region of rapidly deteriorating SNR(C).     

Functional magnetic resonance imaging based on changes in vascular space occupancy.

During brain activation, local control of oxygen delivery is facilitated through microvascular dilatation and constriction. A new functional MRI (fMRI) methodology is reported that is sensitive to these microvascular adjustments. This contrast is accomplished by eliminating the blood signal in a manner that is independent of blood oxygenation and flow. As a consequence, changes in cerebral blood volume (CBV) can be assessed through changes in the remaining extravascular water signal (i.e., that of parenchymal tissue) without need for exogenous contrast agents or any other invasive procedures. The feasibility of this vascular space occupancy (VASO)-dependent functional MRI (fMRI) approach is demonstrated for visual stimulation, breath-hold (hypercapnia), and hyperventilation (hypocapnia). During visual stimulation and breath-hold, the VASO signal shows an inverse correlation with the stimulus paradigm, consistent with local vasodilatation. This effect is reversed during hyperventilation. Comparison of the hemodynamic responses of VASO-fMRI, cerebral blood flow (CBF)-based fMRI, and blood oxygenation level-dependent (BOLD) fMRI indicates both arteriolar and venular temporal characteristics in VASO. The effect of changes in water exchange rate and partial volume contamination with CSF were calculated to be negligible. At the commonly-used fMRI resolution of 3.75 x 3.75 x 5 mm(3), the contrast-to-noise-ratio (CNR) of VASO-fMRI was comparable to that of CBF-based fMRI, but a factor of 3 lower than for BOLD-fMRI. Arguments supporting a better gray matter localization for the VASO-fMRI approach compared to BOLD are provided.     

Effects of low-dose transdermal scopolamine on autonomic cardiovascular control in healthy young subjects

We studied how posture influences the effects of transdermal scopolamine on autonomic cardiovascular regulation in a randomized, double-blind, placebo-controlled crossover study of 10 healthy young volunteers. We recorded the electrocardiogram and auscultatory sphygmomanometric and continuous non-invasive finger arterial pressure (Finapres device) to obtain signals for the beat-by-beat R–R interval and systolic, mean and diastolic pressures. R–R interval and arterial pressure variabilities were characterized by power spectral analysis. Scopolamine increased the mean R–R intervals and reduced arterial pressure in both the supine and the standing positions, but did not affect blood pressure variability. Scopolamine increased the total variability of R–R interval and its mid- (0·07–0·15 Hz) and high- (0·15–0·40 Hz) frequency band power in the standing position during controlled breathing at 0·25 Hz. In the supine position, scopolamine did not affect R–R interval variability. In the deep breathing test, scopolamine increased the maximal expiratory–inspiratory R–R interval ratio. This study showed that low-dose scopolamine increases vagal cardiac inhibition in both supine and standing positions in healthy volunteers. However, scopolamine increases heart rate variability only in the standing position during partial vagal withdrawal. The study also demonstrates that transdermal scopolamine decreases blood pressure in healthy young subjects.     

Association of angiotensin II type 1 receptor gene polymorphism with essential hypertension

The renin-angiotensin system is involved in control of blood pressure and salt and fluid homeostasis. Genes for components of this system have been of major focus in research on the causation of the common, complex, polygenic trait, essential hypertension (HT). Association of an A→C variant at nucleotide 1166 of the angiotensin II type 1 receptor (AT₁R) gene with HT, but an absence of linkage of this locus with this disease, has been reported recently. Since confirmation in a different setting is imperative, we performed a cross-sectional case-control study of the A1166C variant in a well-characterized group of 108 Caucasian HT subjects with a strong family history (two affected parents) and early onset disease. Genotyping was by mismatch polymerase chain reaction/ Bfr I restriction fragment length polymorphism analysis. Frequency of the C¹¹⁶⁶allele was 0.40 in HTs and 0.29 in normotensives. The difference in genotype (χ²= 13, P = 0.0015) and allele (χ²= 5.3, P = 0.02) frequencies between the two groups was significant (odds ratio for CC vs AA+AC = 7.3 [95% CI, 1.9–31.9). The present results implicate the AT₁R gene, or a locus in linkage disequilibrium with the variant tested, in the causation of essential HT.     

Epidural blood patch illustrated by CT-epidurography

Four patients, who received epidural blood patch to treat postdural puncture headache, were examined with computed tomography in order to demonstrate the distribution of the injected blood. Blood alone could not be identified, but adding 2 ml contrast agent Iohexol 180 mg J/ ml (Omnipaque®, Nycomed Imaging) to 18 ml blood gave an excellent demonstration of the distribution of the blood in the epidural space, both cranio-caudally (7–14 segments) and spatially in relation to the epidural septae. The blood-contrast media had a strong affinity to the dural sac. There was no support of the spacefilling effect of blood patch.