DOPPLER ULTRASONOGRAPHIC ESTIMATION OF RENAL AND OCULAR RESISTIVE AND PULSATILITY INDICES IN NORMAL DOGS AND CATS

Resistive index (RI) and pulsatility index (PI) are indirect measurements of blood flow resistance that may be used to evaluate vascular changes in renal and ophthalmologic diseases. To our knowledge, no reports are available describing values for renal and ocular PI index in the unsedated dog and ocular RI and PI indices in the unsedated cat. The purpose of this study was to measure normal values for both intrarenal and ocular RI and PI within the same subject in unsedated clinically normal dogs and cats. Twenty-seven dogs and 10 cats were considered healthy by means of physical examination, CBC, biochemical profile, urinalysis, and ultrasonography. Systolic blood pressure was measured by Doppler ultrasonography. Intrarenal and ocular arteries were scanned by pulsed Doppler ultrasonography to calculate RI and PI. No significant differences were noted between the values obtained for the right vs. the left kidney and eye. The upper values of these indices were calculated as mean+2 standard deviations resulting in 0.72 and 1.52 for dog renal RI and PI; 0.7 and 1.29 for cat renal RI and PI; 0.76 and 1.68 for dog ocular RI and PI; and 0.72 and 1.02 for cat ocular RI and PI.     

基于BPNN的非线性电阻网络故障诊断方法研究

针对非线性电阻网络，提出了一种规范式分段线性化求多值解，并采用BPNN对非线性电阻网络硬故障进行诊断的方法，克服了一般方法对非线性电阻网络硬故障诊断时易存在的漏诊问题。     

Effects of anti-glaucoma drugs on resistive index of the medial long posterior ciliary artery using color Doppler imaging in Beagle dogs

Color Doppler imaging (CDI) was carried out to evaluate the effects of anti-glaucoma drugs on ophthalmic circulation using CDI-derived resistive index (RI) values. CDI was performed on nine Beagle dogs, and RI values were calculated for the medial long posterior ciliary artery before and after the administration of anti-glaucoma drugs. A significant increase in RI values was found after topical administration of levobunolol (p < 0.05) or dipivefrin (p < 0.05). Pilocarpine showed no effects on RI values after topical administration. The results suggest that some anti-glaucoma drugs could affect ophthalmic blood flow.     

Ultrasonographic determination of resistive index and graft size for evaluating clinical feline renal allografts.

Ultrasonographic examination is a commonly employed technique for postoperative renal allograft evaluation after transplantation. Allograft size and resistive index (RI) are two objective ultrasonographic measures that may help establish a diagnosis and direct postoperative management for grafts with suboptimal function but their diagnostic efficacy has not been evaluated in clinical veterinary patients. Results of 69 feline renal transplant ultrasonographic examinations and RI determinations were studied. Based on clinical parameters at the time of the ultrasonographic examination, patients were grouped into six clinical/functional categories including evaluations of clinically normal grafts, delayed graft function, ureteral obstruction, uroabdomen, graft thrombosis, and rejection. RI, graft size (length, cross-sectional area, and volume), cyclosporine A whole blood trough concentration, Doppler blood pressure, creatinine concentration, and days from transplantation were compared between these categories and associations with each other were examined. RI was of little value in differentiating among the clinical categories with the exception of graft thrombosis. Graft volume and time from transplantation were significantly greater in grafts with signs of rejection and ureteral obstruction compared to clinically normal ultrasound examinations. Graft volume, cross-sectional area and length were generally associated. Cyclosporine A blood concentrations was associated with RI in both the pooled data and in the delayed graft function category. These results indicate RI should be used only as part of a larger clinical picture and in light of other factors including cyclosporine A concentration and the timing of the study relative to the implantation surgery for the diagnosis of postoperative transplantation complications. Graft volume may provide a more sensitive, albeit, nonspecific, indicator of allograft dysfunction.     

Ultrasonographic evaluation of renal dimension and resistive index in clinically healthy Korean domestic short-hair cats

Renal length, height, width, resistive index (RI), size of cortex, and medulla were determined by renal ultrasonography in 50 healthy Korean domestic short-hair cats. In the sagittal plane, the renal length was 3.83 ± 0.51 cm (mean ± SD) in the left kidney and 3.96 ± 0.48 cm in the right kidney, whereas the renal height was 2.42 ± 0.27 cm in the left kidney and 2.36 ± 0.28 cm in the right kidney. In the transverse plane, the renal height was 2.42 ± 0.28 cm in the left kidney and 2.38 ± 0.27 cm in the right kidney, whereas the renal width was: 2.65 ± 0.35 cm in the left kidney and 2.63 ± 0.31 cm in the right kidney. In the dorsal plane, the renal length was 3.84 ± 0.53 cm in the left kidney and 3.97 ± 0.54 cm in the right kidney, whereas the renal width was 2.65 ± 0.34 cm in the left kidney and 2.66 ± 0.33 cm in the right kidney. There were no significant differences (p > 0.05) among the same structure sizes measured in different planes. In the sagittal plane, the size of the renal cortex was 0.47 ± 0.08 cm in the left kidney and 0.47 ± 0.08 cm in the right kidney, whereas of the size of the renal medulla was 0.55 ± 0.30 cm in the left kidney and 0.50 ± 0.07 cm in the right kidney. RI evaluated by pulsed wave Doppler sonography was 0.52 ± 0.05 in the left kidney and 0.55 ± 0.05 in the right kidney. The actual renal dimensions determined by gross examination were not statistically different from those determined by ultrasonography. Furthermore the renal dimensions and RI were statistically correlated to the body weight of cats.     

低压微网多逆变电源的综合控制策略设计

针对微电网通常是接入低压配电网的情况,分析了低压微电网输电线路与传统高压输电线路阻抗比的差异,对低压微网功率传输进行了理论修正.在此基础上采用不同的控制策略对低压微电网进行综合控制,联网模式下为了执行支撑本地电压和调节馈线潮流,微电源采用PQ控制策略;孤岛模式下为确保负荷能各自快速分担负载和电压频率稳定,微电源采用电压频率V/f下垂控制.为保证逆变器输出阻抗与线路阻抗相匹配,在逆变器控制策略中引入阻性虚拟阻抗,根据低压线路参数呈阻性的特点,对传统高压大电网下垂特性进行修正,通过旋转坐标正交变换矩阵,对电压频率V/f下垂控制进行了改进,使得传统的V/f下垂控制得以扩展应用于低压微网中．仿真验证分析,证明了低压微电网系统下设计的综合控制策略能够保证系统与运行的稳定性和可靠性.     

THE REAL RESISTIVE MODEL FOR FREQUENCY -DOMAIN ANALYSIS

A new model for frequency - domain analysis - the real resistive model which is based on Complex Network Theory is proposed in this paper. The network equations formed with the new model without contain complex numbers because there are only sources and resirtive elements in the model. A CAA algorithm for frequency analysis by using the new model is also given. It is shown that the trouble with the complex operation in the traditional algorithm has been avoided. The algorithm presented in this paper is simple and convenient,hence it is easy to popularize.     

Influence of ascorbic acid on BUN, creatinine, resistive index in canine renal ischemia-reperfusion injury

Renal ischemia as a course of renal transplantation is a common cause of renal dysfunction as renal failure. The purpose of this study was to investigate the influence of ascorbic acid on blood urea nitrogen (BUN), creatinine (Cr) and resistive index (RI) for dog models with renal ischemia-reperfusion (I/R) injury. Renal ischemia was induced on 6 Beagle dogs. The left kidney was exposed to normothermic ischemia for a short period at 30 min followed by reperfusion. On the blood Cr level and RI, there was no significant difference comparing both groups. 14 days after I/R injury a significant reduction on the blood BUN level was observed in the vehicle group (34.06 mg/dl) compared to that of ischemia induced treated group (10.3mg/dl) (p < 0.05). In conclusion, administration of ascorbic acid for renal ischemic-reperfusion injury had influence on blood BUN level, but it was not revealed the influence on blood Cr and RI.     

EFFECTS OF SEDATION WITH MIDAZOLAM AND BUTORPHANOL ON RESISTIVE AND PULSATILITY INDICES IN HEALTHY DOGS

Resistive index (RI) and pulsatility index (PI) are indirect measurements of blood flow resistance that may be measured by pulsed wave Doppler ultrasonography. Chemical restrain may potentially alter the indices although it is required to perform ultrasonography in some patients. The purpose of this study was to describe values for both intrarenal and ocular RI and PI within the same subject in clinically normal dogs sedated with a midazolam and butorphanol combination and evaluate if there are any significant changes between sedated and nonsedated dogs. Fifteen healthy Beagle dogs were studied by Duplex Doppler interrogation in interlobar or arcuate arteries of the kidney and long posterior ciliary artery. Pulse rate and systolic blood pressure were also determined. All measurements were recorded before and after the administration of a sedative combination of midazolam (0.2 mg/kg) and butorphanol (0.2 mg/kg). Mean comparison tests (paired t-tests or Wilcoxon's rank-sum test) were used to determine if any significant differences existed between right and left renal values or right and left ocular values. A correlation study (Pearson or Spearman) was applied between RI, PI, and systolic pressure, and pulse rate. RI and PI were significantly higher in sedated Beagles than in unsedated Beagles. There was neither correlation between index and systolic blood pressure nor pulse rate. In conclusion, provided that normal RI and PI increase in sedated animals, then reference ranges should be higher when sedated--healthy or ill--animals are evaluated.