彩色多普勒超声对早期高血压患者心脏及血管改变的诊断意义

目的评价彩色多普勒超声对早期高血压患者心脏及血管改变的诊断意义。方法应用彩色多普勒超声探测82例高血压患者及65例健康自愿者的心脏、颈动脉、肾动脉及大脑中动脉血流变化。结果高血压组心室间隔与左室后壁均增厚52例、左房扩大42例、二尖瓣口血流频谱E/A〈1者有72例、颈动脉内膜-中层增厚47例、颈动脉粥样硬化斑36例、肾段动脉阻力指数RI〉0.70者50例、大脑中动脉峰值流速〉106 cm/s者67例,而对照组分别为5、17、12、11、14、15、22例,两组差异均有统计学意义（P〈0.01）。高血压组心脏、颈动脉、肾动脉及大脑中动脉血流均出现异常表现者43例（52.4%）,对照组均无异常。结论彩色多普勒超声可了解早期高血压患者心脏结构、颈动脉内膜情况及肾动脉、脑动脉血流改变。     

Activation of PKCalpha and pulmonary vascular remodelling in broilers

OBJECTIVE: The present study was conducted to examine the presence of protein kinase Calpha (PKCalpha) in the pulmonary arterioles of broilers during the development of pulmonary hypertension and pulmonary vascular remodelling. METHOD: One hundred and sixty day-old Avian-2000 broilers were divided equally into a control group and a cold temperature group. All the birds were reared in normal temperatures up to day 14, with the lighting schedule at 24 h per day. Thereafter, birds in the cold temperature group were subjected to low temperature by lowering 1-2 degrees C per day to 12-14 degrees C, and then kept constant until day 49, while birds in the control group were still brooded at normal temperatures. All the birds were fed a diet of pellets throughout the study. Samples of blood were taken from the wing vein, and of heart and lung collected after the birds were killed with an overdose of sodium pentobarbitial, at days 24, 32, 39 and 45 of age, respectively. Right ventricle to total ventricle ratio (RV/TV) and packed cell volume (PCV) were measured. Vessel wall area to vessel total area ratio (WA/TA) and mean media thickness in pulmonary arterioles (mMTPA) was examined using computer-image analytic software. Expression of PKC in pulmonary muscular arterioles was assessed by immunohistochemistry and quantified by measuring optical density (OD) using computer-image analytic software. RESULTS: The incidence of pulmonary hypertension syndrome (PHS) was 12.5% in birds exposed to cold, and 3.75% in the control group (P<0.05). PCV in the cold temperature group was elevated after day 32 (P<0.05), and RV/TV ratio increased on day 45 (P<0.05). Both the WA/TA and mMTPA of birds subjected to cold were significantly elevated (P<0.05). The OD values were not significantly increased before day 32 (P>0.05), however, one week later (at day 39 of age), the difference between the two groups was significant (P<0.05). The increased PKCalpha expression was positively correlated with the values of mMTPA and WA/TA. CONCLUSION: PKCalpha expression was up-regulated during the development of pulmonary hypertension. The activation of PKCalpha might be involved in the development of pulmonary vascular remodelling.     

Spontaneous feline hypertension: clinical and echocardiographic abnormalities,and survival rate

Systemic hypertension was diagnosed in 58 of 188 untreated cats referred for evaluation of suspected hypertension-associated ocular, neurologic. cardiorespiratory, and urinary disease, or diseases frequently associated with hypertension (hyperthyroidism and chronic renal failure). Hypertensive cats were significantly older than normotensive subjects (13.0 +/- 3.5 years versus 9.6 +/- 5.0 years; P < .01), and had a greater prevalence of retinal lesions (48 versus 3%; P < .001), gallop rhythm (16 versus 0%; P < .001), and polyuria-polydipsia (53 versus 29%: P < .01). Blood pressure was significantly higher (P < .001) in cats with retinopathies (262 +/- 34 mm Hg) than in other hypertensive animals (221 +/- 34 mm Hg). Hypertensive cats had a thicker interventricular septum (5.8 +/- 1.7 versus 3.7 +/- 0.64 mm; P < .001) and left ventricular free wall (6.2 +/- 1.6 versus 4.1 +/- 0.51 mm; P < .001) and a reduced diastolic left ventricular internal diameter (13.5 +/- 3.2 versus 15.8 +/- 0.72 mm; P < .001) than control cats. Left ventricular geometry was abnormal in 33 of 39 hypertensive subjects. No significant difference was found in age or blood pressure at the initial visit between cats that died or survived over a 9-month period after initial diagnosis of hypertension. Mean survival times were not significantly different between hypertensive cats with normal and abnormal left ventricular patterns. Further prospective studies are needed to clearly identify the factors involved in survival time in hypertensive cats.     

Pulmonary Hypertension Induced in Dogs by Hypoxia at Different High-Altitude Levels

Chronic natural hypoxia at 2300 m altitude induces mild pulmonary hypertension (PH) in healthy dogs. The influence of more severe hypoxia on the same group of dogs was evaluated by re-examining such dogs at 3500 m, after they had regularly exercised at this altitude level for half a year. Despite severe hypoxaemia at 3500 m (P _aO₂ 52±5 mmHg), none of the dogs developed erythrocytosis, and their PCV at 3500 m (48%±4%) did not differ from that at 2300 m (49%±4%). There was a tendency towards an elevated systemic BP, with a significant increase in diastolic BP (105±13 mmHg at 3500 m versus 98±17 at 2300 m). Tricuspid regurgitation (TR) was detected in 7 dogs at 3500 m compared to 8 dogs at 2300 m. The mean TR V _max was significantly higher at 3500 m, and all 7 dogs had systolic PH at 3500 m (33.6–54.8 mmHg), when PH was defined as TR V _max 2.8 m/s, i.e. a peak pressure gradient >30 mmHg. Hence, in dogs, increasing altitude and the concomitant hypoxia result in a progressively more pronounced PH and an elevated systemic BP. Intermittent severe hypoxaemia of around 50 mmHg may not cause erythrocytosis in healthy dogs, even over a prolonged period.     

Presumptive Baclofen Intoxication in a Dog

A five year old mixed breed dog weighing 30 kg., presumptively ingested six to twelve 20 mg baclofen tablets four to six hours prior to admission. The dog had been ataxic and vocalizing at home but was stuporous on presentation. Toxic effects noted were hypothermia, hypertension and sedation, followed by prolonged agitation. Treatment consisted of administration of activated charcoal, fluid diuresis, sodium nitroprusside, and diazepam. Baclofen overdose has been reported frequently in humans, but this is the first report of it in a dog. (Vet Emerg & Crit Care, 1998; 8: 49–54)     

L-精氨酸对肺动脉高压肉鸡肺动脉NOS活性的影响

240羽商品代肉鸡于14d时随机等分为常温对照组(NT),低温组(LT)和低温加L精氨酸(L arg)组(LA)。自14d起,对LT和LA组肉鸡采用低温诱导肺动脉高压综合征(PHS)。此外,LA组自14d起在饲料中按100mg·kg-1剂量添加L arg。测定右心室/全心室(RV/TV)和血浆一氧化氮(NO)水平。肺组织切片经βNADPH组织化学染色后,检测直径在100～200μm的肺小动脉平均光密度(D)值,以D值代表NOS的活性。结果显示:LT组PHS发病率显著高于对照组(P<0.05);LA组与对照组相比无显著差异(P>0.05),但显著低于LT组(P<0.05)。LT组肉鸡RV/TV在45d时显著升高(P<0.05),血浆NO浓度总体上与NT组差异不显著(P>0.05);LA组肉鸡RV/TV值与NT组相比无显著差异(P>0.05),其血浆NO浓度自32d时起较NT和LT组显著升高(P<0.05)。LT组肉鸡肺动脉D值较NT组显著降低(P<0.05);LA组D值仅在24d时降低(P<0.05),在其余时间段与NT组相比无显著差异(P>0.05),但显著高于LT组(P<0.05)。上述结果提示,添加L arg可在一定程度上保护并激活肺动脉NOS活性,从而使内源性NO合成增加。     

内皮素在肺动脉高压综合征肉鸡中的作用

通过急性试验确定内皮素（Endothelin，ET）对试验肉鸡肺动脉压的升压作用及其量效关系；在肉鸡快速生长期长时间给予ET，观察试验鸡发病率变化。结果表明：（1）在25ng／kg剂量静脉给予时，可引起肉鸡肺动脉压升高并达到与发病鸡相近的水平。（2）长期给予ET后，试验组30d发病率为6．7％，44d发病率13．3％，对照组发病率为0。同时，试验组红细胞压积（PCV）、腹水心脏指数（AHI）亦显著高于对照组。此结果表明，ET-1可通过缩血管效应引起肺动脉压升高，是致发肉鸡腹水综合征的一个重要因素。     

肺动脉高压综合征发病过程中肉鸡血清和肺脏iNOS和cNOS活性变化

常规饲养条件喂养的大群AA肉鸡，按临床症状分为肺动脉高压组（M组），肺动脉高压腹水组（S组）和正常对照组（C组）。分别测定21、28、35和42日龄S组、M组和C组肉鸡的腹水心脏指数（AHI）、全心与体重比（WH／BW）、平均肺动脉高压（mPAP）、血清一氧化氮（NO）水平、肺脏和血清cNOS和iNOS活性。试验结果表明：（1）S组和M组全心与体重比值（TV／BW）以及S组血清NO水平均从28日龄起显著或极显著高于C组（P〈O．01或P〈0．05）；（2）S组肺组织cNOS水平显著或极显著低于C组（P〈0．01或P〈0．05）；（3）S组肺组织iNOS在21、35和42日龄显著或极显著高于C组（P〈0．01或P〈0．05）；（4）S组从28日龄起血清中cNOS和iNOS与C组差异显著或极显著（P〈0．01或P〈0．05）；（5）正常对照组肉鸡血清中iNOS活性在21、35和42日龄均显著或极显著低于血清中cNOS活性（P〈0．01或P〈0．05）。此研究结果提示cNOS和iNOS活性的变化与PHS发病机理有着密切的关系，并在其中发挥着重要的作用。     

Serum-effusion albumin gradient in dogs with transudative abdominal effusion

A prospective clinical study in dogs with transudative abdominal effusions examined the clinical usefulness of the serum albumin-effusion albumin (SA-EA) gradient. In humans, the SA-EA gradient facilitates classification of abdominal effusion, with a gradient > or = 1.1 indicating the presence of portal hypertension. Gradient values proved useful for predicting therapeutic response to sodium restriction and diuresis in humans. Of 49 dogs evaluated, 25 had hepatobiliary disease (group 1) and 24 had other nonhepatobiliary conditions (group 2). Portal hypertension was clinically suspected in 24 of 25 dogs in group 1 and in 15 of 24 dogs in group 2. A broad range of SA-EA gradients was found. A gradient > or = 1.1 was found in 22 of 25 (88.0%) dogs with liver disease and in 14 of 24 (58.3%) dogs with other disorders. The median SA-EA gradient was higher in group 1 than in group 2, with values of 1.4 (range, 0.7-3.1) and 1.1 (range, 0.3-2.6), respectively (P < .04). Considerable overlapping of SA-EA gradients occurred between groups and among dogs with diverse conditions such that gradient values could not distinguish dogs with hepatobiliary disease from dogs with other conditions. The overall diagnostic accuracy of the SA-EA gradient in predicting portal hypertension in dogs with and without hepatobiliary disease (69.4%) exceeded that of hypoalbuminemia (57.1%). These findings suggest that portal hypertension is a predominant force in formation of transudative abdominal effusion in dogs with hepatobiliary disease and in dogs with other disorders. Whether the SA-EA gradient can be used to guide therapeutic mobilization of effusion in dogs remains to be proved.     

DOPPLER ULTRASONOGRAPHIC DIAGNOSIS AND ANATOMY OF CONGENITAL INTRAHEPATIC ARTERIOPORTAL FISTULA IN A PUPPY

A dilated, tortuous blood vessel was identified sonographically in the right medial liver lobe in a puppy with severe ascites. This vessel was thought to represent the dilated right medial portal vein branch. Using pulsed wave Doppler ultrasonography, retrograde, abnormally pulsatile flow was detected in both the dilated right medial portal vein branch and the main portal vein. The right medial liver lobe was surgically resected then fixed in formalin. Silicon rubber was injected and outlined the connection between the portal vein and hepatic artery.