Effects of diffuse fatty infiltration of the liver on portal vein flow hemodynamics

PURPOSE: To investigate the effects of various degrees of diffuse fatty infiltration of the liver on portal vein blood flow with Doppler sonography. METHODS: One hundred forty subjects were examined with color and spectral Doppler sonography. The subjects were divided into 4 groups of 35 subjects each according to the degree (normal, grade 1, grade 2 and grade 3) of hepatic fatty infiltration assessed on gray-scale images. The portal vein pulsatility index (VPI) and time-averaged mean flow velocity (MFV) were calculated for each subject. VPI was calculated as (peak maximum velocity - peak minimum velocity) / peak maximum velocity. RESULTS: VPI and MFV values were, respectively, 0.32 +/- 0.06 and 16.8 +/- 2.6 cm/second in the normal group, 0.27 +/- 0.07 and 14.2 +/- 2.2 cm/second in the group with grade 1 fatty infiltration, 0.22 +/- 0.06 and 12.2 +/- 1.8 cm/second in the group with grade 2 fatty infiltration, and 0.18 +/- 0.04 and 10.8 +/- 1.5 cm/second in the group with grade 3 fatty infiltration. There was a negative inverse correlation between the grade of fatty infiltration and both VPI (f = 55.3, p < 0.001) and MFV (f = 43.9, p < 0.001). CONCLUSION: The pulsatility index and mean velocity of the portal vein blood flow decrease as the severity of fatty infiltration increases.     

白细胞介素-2和10 mRNA表达差异在CD4+CD25+T细胞诱导大鼠肝移植免疫耐受中的意义

目的 探讨白细胞介素-2(IL-2)mRNA及IL-10 mRNA表达水平对大鼠肝移植耐受的影响.方法 将实验大鼠随机分3组:Ⅰ组为急性排斥组; Ⅱ组为CD4+CD25+T细胞处理组,供体Wistar大鼠,受体SD大鼠;Ⅲ组为移植对照组,供体、受体均为SD大鼠.每组12对.肝移植前7 d,Ⅱ组受体大鼠经阴茎背静脉注射含供体脾淋巴细胞的培养液,Ⅰ组、Ⅲ组注射等量生理盐水;术后7 d随机取6只大鼠用逆转录-聚合酶链反应(RT-PCR)测定肝组织中细胞因子IL-2 mRNA及IL-10 mRNA的表达,用流式细胞仪检测各组移植肝内分离出的淋巴细胞含量,同时检测肝脏病理学的变化;另6只观察移植大鼠的生存期.结果 IL-2mRNA在Ⅰ组大鼠移植物内出现高表达,Ⅱ组仅有微弱表达,Ⅲ组则未见表达,IL-10 mRNA仅在Ⅱ组中表达,且表达程度较强.Ⅱ组和Ⅲ组大鼠存活期均超过30 d,与Ⅰ组(8～11 d)比较差异有统计学意义(P均＜0.01).Ⅰ组大鼠移植后肝脏有大量淋巴细胞浸润,数量明显高于Ⅱ组和Ⅲ组[(14.31±3.41)×106 /g比(5.04±1.13)×106 /g和(1.55±0.40)×106 /g,P均＜0.01],且显示中度排斥反应.Ⅱ组大鼠有中等量淋巴细胞浸润,病理为无排斥或不确定性排斥,且淋巴细胞中CD4+百分比[(43.31±8.07)%]和CD4+CD25+百分比C(11.39±1.92)%]均显著高于Ⅰ组[(33.65±7.25)%,(3.05±0.62)%]和Ⅲ组[(31.18±6.52)%,(3.37±0.72)%],差异有统计学意义(P＜0.05或P＜0.01).Ⅲ组未见明显淋巴细胞浸润,病理为无排斥反应.结论 IL-2参与了移植排斥的发生,而IL-10在CD4+CD25+T细胞诱导免疫耐受中具有非常重要的作用.     

一氧化氮对急性出血坏死性胰腺炎肝脏中Toll样受体2/4 mRNA表达的影响

目的探讨一氧化氮(NO)对于急性出血坏死性胰腺炎(AHNP)时肝脏中T o ll样受体2/4(TLR 2/4)mRNA表达的影响。方法采用牛磺胆酸钠(TAC)逆行胰胆管注射制备AHNP肺损伤大鼠模型。动物分为假手术组、胰腺炎组和L精氨酸(L A rg)治疗组。假手术组于术后6 h,胰腺炎组和L A rg组分别于术后3、6、12 h取静脉血和肝组织,测定血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(A ST)、淀粉酶和肝组织NO,逆转录聚合酶链反应(RT PCR)方法检测不同时间点肝组织肿瘤坏死因子α(TNFα)、TLR 2/4mRNA表达变化。结果与假手术组比较,胰腺炎组大鼠3 h肝组织TLR 2/4 mRNA表达开始增高〔(1.970±0.362)×10-3,(175.000±0.111)×1-0 3比(1.150±0.725)×10-6,(11.450±1.724)×10-4,〕12 h表达达峰值〔(2.940±0.316)×1-0 3,(2 673.000±88.380)×1-0 3,P均<0.01〕;血清淀粉酶ALT、A ST 3 h后即升高,肝损伤加重,肝组织TNFαmRNA表达升高,NO浓度逐渐降低(P<0.05或P<0.01);给予L A rg治疗后,NO浓度升高(P<0.05),TLR 2/4 mRNA表达降低〔3 h:(0.351±0.153)×1-0 3,(135.000±22.310)×1-0 3;6 h:(2.100±0.535)×10-3,(187.000±26.850)×1-0 3;12 h:(2.620±0.208)×1-0 3,(1 959.000±270.000)×10-3;P<0.05或P<0.01〕,血清淀粉酶、ALT、A ST均降低,肝损伤减轻,肝组织TNFαmRNA降低(P<0.05或P<0.01)。结论AHNP时,肝组织内TLR 2/4 mRNA表达上调,肝组织损伤加重;NO可以明显抑制AHNP肝组织TLR 2/4 mRNA的表达。     

Effects of free fatty acids on carbohydrate metabolism and insulin signalling in perfused rat liver

BACKGROUND: Elevated circulating free fatty acids (FFAs) induce insulin resistance and play a crucial role in the development of type 2 diabetes, in which fasting hepatic glucose production (HGP) is increased. However, direct effects of FFAs on fasting HGP are still unclear because indirect endocrine and metabolic effects contribute to FFA action. Thus, we aimed to investigate acute direct effects of specific FFAs on fasting HGP, lactate uptake, and insulin signalling. MATERIALS AND METHODS: Isolated livers obtained from 20 h fasted rats were perfused with albumin-bound palmitate or oleate (200 micromol L(-1) each) or vehicle (control) for 180 min (n = 5-7/group). RESULTS: Compared to control, hepatic lactate uptake was increased by palmitate and oleate (~+40%; P < 0.05), while HGP from lactate (~3 mmol L(-1)) and liver glycogen content were similar. Tyrosine phosphorylation (pY) of insulin-receptor-substrate-(IRS)-2 and p70S6-kinase phosphorylation were not affected by FFAs. Palmitate decreased insulin-receptor-beta pY, IRS-1 pY and phosphoinositol-3-kinase expression by 46 +/- 16%, 46 +/- 11% and 20 +/- 9%, respectively (P < 0.03), while oleate reduced Akt phosphorylation by 85 +/- 7% (P < 0.006). CONCLUSIONS: Isolated liver perfusion with saturated or unsaturated FFAs reduced insulin signalling protein phosphorylation at different sites and increased lactate uptake without affecting HGP or glycogen content. These results suggest that at fasting, both saturated and unsaturated FFAs increase hepatic glucose precursor uptake and may, independently of insulin's presence, accelerate protein dephosphorylation of the insulin signalling cascade at different sites.     

彩色多普勒超声对门脉高压食管静脉曲张出血的诊断价值

目的评价门脉血流动力学参数在预测肝硬化食管静脉曲张高危患者中的作用。方法对85例肝硬化患者行胃镜和彩色多普勒超声检查,使用单因素分析和多元分析对门脉血流动力学指标与确认的食管静脉曲张的存在和规模间的关系进行评估。结果食管静脉曲张组的肝动脉阻力指数、脾动脉阻力指数、充血指数、门脉高压指数较无食管静脉曲张组大,肝血管指数较无食管静脉曲张组小,食管静脉曲张重度组的肝动脉阻力指数、脾动脉阻力指数、脾脏长径、充血指数、门脉高压指数较轻-中度组大,肝血管指数较轻-中度组小,差异均有统计学意义（P〈0．05）。结论彩色多普勒超声对门脉高压食管静脉曲张出血有较高的诊断价值。     

祛瘀化浊颗粒对非酒精性脂肪肝胰岛素抵抗的影响

目的:通过观察祛瘀化浊颗粒对非酒精性脂肪肝胰岛素抵抗(IR)的影响,探讨祛瘀化浊颗粒治疗非酒精性脂肪肝的作用机制。方法:运用祛瘀化浊颗粒治疗非酒精性脂肪肝患者40例(治疗组),并与对照组(多烯磷脂酰胆碱治疗脂肪肝)患者40例作对照,观察治疗前后肝功能、肝/脾CT值、胰岛素抵抗指数(HOMA-IR)。结果:治疗组总有效率为85.0%,对照组总有效率为82.5%,两组比较差异无统计学意义(P>0.05);两组均能明显改善患者胰岛素抵抗指数,两组比较P<0.05,治疗组疗效显著优于对照组。结论:改善胰岛素抵抗是祛瘀化浊颗粒治疗脂肪肝的可能机制。     

超声背向散射积分定量评价大鼠肝脏脂肪变

目的通过测量四氯化碳诱导的大鼠脂肪变肝脏超声背向散射积分值(IBS),并与病理对照,探讨超声背向散射积分定量评价大鼠肝脏脂肪变的价值。方法测量正常大鼠及四氯化碳作用下的大鼠肝脏近场及远场IBS参数:平均值(AII)、离散度(SDI)及校正AII(AII%)。同时取病理且按照病理诊断将测量结果分组为:正常无脂肪变组(对照组)、轻度脂肪变组(组1)、中度脂肪变组(组2)、重度脂肪变组(组3)。结果(1)各病例组AII、AII%均高于对照组,同时病例组的AII、AII%值随脂肪变的不断加重而逐渐增大,且差异显著(P<0.01);(2)各病例组AII%值与病理脂肪变程度之间密切相关(r=0.63,P<0.01)。结论超声背向散射技术能定量评价脂肪肝,且能判断肝脏脂肪浸润的程度。     

2型糖尿病合并非酒精性脂肪肝42例临床分析

目的探讨2型糖尿病患者非酒精性脂肪肝的发生是否与胰岛素抵抗及血脂代谢紊乱有关。方法收集本院96例2型糖尿病患者，全部病例肝脏B超扫描证实，将其分为2型糖尿病合并脂肪肝组42例与2型糖尿病无脂肪肝组54例，同时测定两组病人的体重、TG、TC、HDL、LDL、空腹血糖（FBs）、空腹血胰岛素水平（FINS），并计算胰岛素抵抗指数（IRI）等。结果2型糖尿病合并脂肪肝组与无脂肪肝组相比较，血TG、LDL、FINS、IRI增高（P≤0．05）；HDL下降（P≤0．05）：TC、FBS无明显差异（P〉0．05）。结论2型糖尿病患者合并非酒精性脂肪肝与血脂代谢紊乱、胰岛素抵抗及肥胖等有关。     

非酒精性脂肪肝患者肝静脉血流多普勒频谱形态的观测

目的观测非酒精性脂肪肝肝静脉血流频谱形态的变化情况。方法多普勒超声检测病例组138例非酒精性脂肪肝患者（弥漫性脂肪肝97例，局灶性脂肪肝41例）与对照组91例正常人肝静脉多普勒频谱。病例组所有患者均经超声检查及CT检查诊断脂肪肝，血脂增高，无长期大量饮酒史。对照组经超声及CT检查诊断无脂肪肝，血脂正常。根据多普勒频谱特点将肝静脉波形分为正常型、衰减型、平坦型。结果病例组异常肝静脉波形（衰减型与平坦型）所占比例（59％）较对照组（7％）显著增加，差异有显著性意义（P〈0．05），异常肝静脉波形中衰减型（59％）与平坦型（41％）所占比例差异无显著性意义（P〉0．05）。弥漫性脂肪肝异常肝静脉波形比例（69％）高于局灶性脂肪肝（37％），差异有显著性意义（P〈0．05）。结论脂肪肝患者肝静脉血流频谱可出现异常衰减型、异常平坦型，对脂肪肝肝血流动力学的进一步研究有助于提高对此疾病的诊断、治疗。     

Contrast-enhanced Doppler perfusion index: clinical and experimental evaluation.

OBJECTIVE: To assess the potential of the power Doppler signal intensity rate of enhancement due to contrast agent wash-in for assessment of hepatic hemodynamics. METHODS: With the use of standardized settings, power Doppler sonography was performed before and after administration of a contrast agent. Video-recorded examinations were digitized for offline analysis on a personal computer. The temporal changes of the power Doppler signal intensity were quantified to provide contrast agent wash-in curves. The contrast-enhanced Doppler perfusion index was defined by the ratio of the wash-in gradient of the hepatic artery and portal vein as contrast-enhanced Doppler perfusion index = hepatic artery gradient/(hepatic artery gradient + portal vein gradient). The contrast-enhanced Doppler perfusion index was evaluated at 4 contrast agent doses in each of 14 patients with liver metastases and 3 patients with hemangiomas. An in vitro flow model was used to determine the relationships between the power Doppler rate of enhancement and flow in vessels of 4, 8, and 12 mm in diameter. RESULTS: In vivo, there was a significantly higher (P < .0001) mean contrast enhanced Doppler perfusion index in patients with liver metastases (mean, 0.59; 95% confidence interval, 0.54-0.63), compared with patients with hemangiomas (mean, 0.33; 95% confidence interval, 0.24-0.41). The corresponding coefficients of variations were 25% for patients with liver metastases and 31% for patients with hemangiomas. In vitro, the power Doppler rate of enhancement was proportional to flow speed and independent of vessel diameter. CONCLUSIONS: Measurement of the contrast-enhanced Doppler perfusion index may have potential in assessment of hepatic hemodynamics and focal liver disease.     

Hepatic arterial resistance after mixed-meal ingestion in healthy subjects and patients with chronic liver disease.

PURPOSE: This study investigated hemodynamic changes in the resistance index of the hepatic artery after mixed-meal ingestion. METHODS: We used color Doppler sonography to measure hemodynamic changes in the right hepatic artery in response to mixed-meal ingestion (225 ml, 69 g, 300 kcal) in 9 healthy subjects, 15 patients with chronic hepatitis with low-grade fibrosis (no bridging), 10 patients with chronic hepatitis with moderate-grade (bridging) fibrosis, and 18 patients with cirrhosis. RESULTS: After mixed-meal ingestion, the mean (+/-standard error) maximum increase in the resistance index of the right hepatic artery in healthy subjects was 31+/-2%. These changes were significantly greater than those in patients with chronic hepatitis with low-grade fibrosis (22+/-2%; p<0.05), patients with chronic hepatitis with moderate-grade fibrosis (11+/-2%; p<0.01), and cirrhotic patients (5+/-2%; p<0.01). Mixed-meal ingestion produced significantly smaller increases in the resistance index in cirrhotic patients than in patients with chronic hepatitis with low-grade fibrosis (p<0.01). A postprandial increase in the resistance index of 15% or less was associated with 100% sensitivity, 72% specificity, and 84% accuracy in distinguishing patients with cirrhosis from patients with chronic hepatitis. CONCLUSIONS: The response of the resistance index after mixed-meal ingestion decreases as the severity of hepatic fibrosis increases. Doppler evaluation of postprandial increases in the resistance index of the right hepatic artery may be useful in differentiating between patients with chronic hepatitis and those with cirrhosis.     

Changes in renal artery resistance after meal-induced splanchnic vasodilatation in cirrhotic patients.

PURPOSE: A relationship between vasomotor tone changes in mesenteric and renal vessels in cirrhotic patients has been suspected but remains controversial. The aim of this study was to assess by duplex Doppler sonography the changes in the circulatory resistance of the renal arteries and superior mesenteric artery (SMA) following meal-induced splanchnic vasodilatation. METHODS: Twenty-seven cirrhotic patients and 15 healthy volunteers with no hepatic or renal dysfunction were prospectively included in the study. The resistance index (RI) of the SMA and of the right and left renal arteries was measured by duplex Doppler sonography before and 30 minutes after ingestion of a standard 400-kcal balanced liquid meal. Values in controls and patients and values before and after the meal were compared, and correlations between RIs, Child-Pugh class (liver function), and creatinine clearance were assessed in cirrhotic patients. RESULTS: The fasting renal artery RI was greater in cirrhotic patients than in controls (p < 0.0001), but there was no difference in fasting SMA RIs. After the meal, there was a significant decrease in the SMA RI in controls (0.85 +/- 0.04 before versus 0.74 +/- 0.03 after meal, p = 0.0001) and in cirrhotic patients (0.85 +/- 0.04 before versus 0.77 +/- 0.04 after, p = 0.0001) and a significant increase in the renal artery RI (0.57 +/- 0.06 before versus 0.62 +/- 0.05 after in controls, p = 0.001; 0.68 +/- 0.07 before versus 0.70 +/- 0.07 after in cirrhotic patients, p = 0.001). No correlation was found in cirrhotic patients between the changes in renal artery RI and the postprandial SMA RI decrease, the Child-Pugh class, or the creatinine clearance. CONCLUSIONS: Meal-induced SMA vasodilatation (RI decrease) is associated with a marked increase in the renal artery RI, worsening the renal vasoconstriction in cirrhotic patients.     

Alterations in thyroid Doppler arterial resistance indices, volume and hormones in cirrhosis: relationships with splanchnic haemodynamics

The hypothesis of thyroid involvement in the haemodynamic alterations of cirrhosis was evaluated. We measured thyroid volume (thrV), free triiodiothyronine (FT3), free thyroxin (FT4), thyroid stimulating hormone (TSH), resistance index (thrRI) and pulsatility index (thrPI) in the inferior thyroid artery in 45 cirrhotic patients of different aetiologies and Child class, and in 13 healthy subjects. Portal vein velocity, flow, diameter and hepatic, splenic, and renal arterial resistance indices were also evaluated. ThrV was increased in Child-C patients (p < 0.05). FT3 was decreased in cirrhotic patients (p < 0.05), TSH and FT4 were not different. ThrPI and thrRI were increased in cirrhotic patients (thrPI: 1.01 +/- 0.15 vs. 0.81 +/- 0.11; thrRI: 0.62 +/- 0.05 vs. 0.53 +/- 0.04; p < 0.01) and were inversely correlated with FT3 (p < 0.05), and directly correlated with hepatic, splenic and renal resistance indices (p < 0.01). In conclusion, thyroid is involved, primarily and secondarily, in the haemodynamic alterations of cirrhosis; a reduction in vasodilator FT3 may play a role in the pathophysiology.     

A new method for attenuation coefficient measurement in the liver: comparison with the spectral shift central frequency method.

OBJECTIVE: To assess the feasibility of a new method of measuring the attenuation coefficient in the liver, which offers less variability of results than the conventional method. METHODS: The attenuation coefficient was evaluated on the basis of the following equation with sound field correction: [log(M0 (z)) - tau(z)]. In our system, the attenuation coefficient was also evaluated by the spectral shift central frequency method at the same time. We used 44 cases of normal liver, 40 cases of fatty liver, and 20 cases of cirrhotic liver in the system. RESULTS: With this new method, attenuation coefficient values were 0.59+/-0.10 dB x cm(-1) x MHz(-1) in normal livers, 0.80+/-0.12 dB x cm(-1) x MHz(-1) in fatty livers, and 0.62+/-0.09 dB x cm(-1) x MHz(-1) in cirrhotic livers. In both methods we recorded a statistically significant difference between normal and fatty livers and between fatty and cirrhotic livers (P < .0001). Only in the fatty liver was any significant difference (P < .0001) found between attenuation coefficients in the new method and those in the spectral shift central frequency method (0.70+/-0.05 dB x cm(-1) x MHz(-1)). CONCLUSIONS: This new method, which was more sensitive in detecting fatty infiltration than the spectral shift central frequency method, was considered usable for evaluating the attenuation coefficient of the liver in vivo.     

Effects of alpha - and beta -adrenergic stimulation on hepatosplanchnic perfusion and oxygen extraction in endotoxic shock

OBJECTIVE: To examine the effects of adrenergic stimulation on hepatosplanchnic perfusion, oxygen extraction, and tumor necrosis factor-alpha production during endotoxic shock. DESIGN: In vivo, prospective, randomized, controlled, repeated-measures, experimental study. SETTING: Experimental physiology laboratory in a university teaching hospital. SUBJECTS: Twenty-one anesthetized and mechanically ventilated dogs. INTERVENTIONS: An intrapericardial catheter was positioned. Catheters for blood sampling were inserted into the right femoral artery, hepatic vein, portal vein, and pulmonary artery. Ultrasonic flow probes were placed around the portal vein, the hepatic artery, the mesenteric artery, the left renal artery, and the left femoral artery. Animals received 2 mg/kg of Escherichia coli endotoxin, followed by fluid resuscitation. Seven dogs received intravenous isoproterenol (0.1 microg/kg x min(-1)), seven received phenylephrine (1 microg/kg x min(-1)), and seven served as controls. Thirty minutes later, cardiac tamponade was introduced to study organ perfusion and tissue oxygen extraction capabilities. MAIN RESULTS: The isoproterenol group had a higher cardiac index and stroke index and lower systemic vascular resistance than the other groups. The phenylephrine group had a higher arterial pressure but a lower cardiac index than the isoproterenol group. The isoproterenol group had a higher hepatic artery blood flow than the other groups and a higher portal and mesenteric flow than the control group. Liver and gut mucosal blood flow was greater in the isoproterenol than in the phenylephrine group. The isoproterenol group had a lower global critical oxygen delivery than the other groups (8.8 +/- 1.3 vs. 13.1 +/- 2.0 (control) and 11.8 +/- 3.3 mL/kg x min(-1) (phenylephrine); both p < .05) and a higher liver critical oxygen extraction ratio than the control group. Isoproterenol tended to attenuate, but phenylephrine significantly increased, blood tumor necrosis factor levels. CONCLUSIONS: During endotoxic shock, beta-stimulation can improve hepatosplanchnic perfusion and enhance tissue oxygen extraction capabilities, whereas alpha-stimulation does not. In addition, alpha-adrenergic stimulation can increase tumor necrosis factor levels.     

正常人肝动脉及其分支的彩色多普勒探查

目的探讨正常人的肝动脉及其分支的血流动力学特点.方法应用彩色多普勒超声对30例正常人肝动脉及其分支,包括第一肝门处肝动脉主干(HA1)、门静脉左支矢状切面处的左肝动脉(HA2)、右肝动脉近末梢支(HA3)的血流进行多普勒频谱分析,观察搏动指数(PI)、阻力指数(RI)、收缩期峰值流速(PSV)、平均流速(Vm)和舒张末流速(EDV).结果正常人HA1及其HA2超声显示率100%,HA3显示率为80%(24/30).各级肝动脉的PI(搏动指数)和RI(阻力指数)无明显统计学差异,而各级肝动脉的流速(包括PSV、Vm、EDV)自主干向分支递减,各组间存在明显统计学差异.结论影响肝动脉的彩色多普勒显示率和频谱参数的因素较多,超声医师必须熟悉解剖,掌握操作技巧和彩色多普勒技术,寻找合适的检查部位.     

运动对高脂饮食诱导非酒精性脂肪肝的治疗作用

目的 观察运动对高脂饮食诱导非酒精性脂肪肝的治疗作用,并初步探讨其相关机制.方法 将30只Wistar大鼠分为对照组及高脂组,分别给予基础饲料和高脂饲料喂养;高脂组大鼠经喂养18周后制成胰岛素抵抗(IR)模型,并进一步细分为静息组和运动组,继续给予高脂饲料喂养,运动组同时进行游泳训练,共持续6周.于实验进行24周后处死各组大鼠,计算肝指数,观察肝脏病理学改变,检测各组大鼠肝脏甘油三酯(TG)含量,同时应用蛋白免疫印迹法检测肝脏组织一磷酸腺苷活化蛋白激酶(AMPK)磷酸化水平.结果 实验进行24周后,与对照组比较,静息组大鼠胰岛素敏感性显著降低,肝脏TG含量、肝指数明显增高,光镜下肝脏出现明显脂肪变性,肝脏内AMPK磷酸化水平降至对照组水平的50.8%;与静息组比较,运动组大鼠胰岛素敏感性明显提高,肝指数及肝脏TG含量均显著降低,光镜下可见肝脏脂肪变性程度明显改善,肝组织内AMPK磷酸化水平亦显著提高.结论 运动干预对高脂饮食诱导的非酒精性脂肪肝具有治疗作用,其机制可能与运动上调肝脏组织中AMPK磷酸化水平,从而改善IR及减少肝脏内TG含量有关.     

苦参碱对高脂-脂肪肝模型大鼠肝脏COX-2、iNOS表达的影响

目的 研究苦参碱对高脂-脂肪肝模型大鼠的治疗作用及对肝脏环氧化物酶2（COX-2）、诱导型一氧化氮合酶（iNOS）表达的影响.方法 选用4周龄Wistar大鼠30只,体重为113～ 138 g,平均（125.6±7.0）g.随机分为3组：正常对照组（C组,n=10）、高脂模型组（M组,n=10）、苦参碱治疗组（Ma组,n=10）,雌雄各半.正常对照组投喂普通颗粒饲料,其他组以高脂饲料替代普通饲料投喂.动物造模3周后,C组和M组给生理盐水,Ma组苦参碱36mg·kg-1 ·d-1灌胃治疗,共30 d.所有实验动物末次给药后麻醉,腹主动脉采血,分离血清,取肝脏.测定肝指数,肝中甘油三酯（TG）、总胆固醇（TC）的含量,血清TG、TC、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）含量,HE组织病理学分析,荧光定量PCR和免疫组化检测肝脏COX-2、iNOS mRNA转录和蛋白表达水平.结果 高脂饮食能够引起大鼠脂肪代谢紊乱,肝指数升高,肝组织中TG、TC和血清中TG、TC、HDL-C、LDL-C升高（P＜0.05）,肝细胞变性坏死和肝组织炎症损伤（P＜0.05）,肝脏COX-2、iNOS mRNA转录和蛋白表达量增高（P＜0.01）;与模型组比较,苦参碱能够降低肝指数、肝组织中TG、TC和血清中TG、TC、HDL-C、LDL-C含量（P＜0.05）,阻止肝细胞变性坏死,抑制炎症损伤（P＜0.01）,降低肝脏COX-2、iNOS mRNA转录和蛋白表达水平（P＜0.01）.结论 苦参碱对高脂-脂肪肝大鼠疗效明显,其作用机制可能与抑制COX-2、iNOS mRNA转录和蛋白表达,阻止炎症发生和抗氧化有关.     

Studies on frequency-dependent attenuation in the normal liver and spleen and in liver diseases, using the spectral-shift zero-crossing method

This report presents results of studies using the spectral-shift zero-crossing method to measure frequency-dependent attenuation (FDA) in normal liver and spleen and in diseased liver. We developed a new system for attenuation analysis that calculated FDA in dB/cm/MHz according to the following equation: (formula: see text). Data are collected from the region of interest on the scan image. Graphite-gel phantoms of known attenuation value are used to create a high degree of accuracy in this new system. Mean attenuation of normal livers was 0.55 +/- 0.05 dB/cm/MHz, while that of normal spleen was 0.37 +/- 0.06 dB/cm/MHz. No correlation between FDA and age could be seen. FDA was 0.81 +/- 0.17 dB/cm/MHz in fatty liver, 0.63 +/- 0.13 dB/cm/MHz in liver cirrhosis, and 0.64 +/- 0.12 dB/cm/MHz in chronic hepatitis. These values are higher than those obtained from normal liver, while tumor masses in the liver (hepatocellular carcinoma, hepatoblastoma, hemangioma) and diffuse infiltration by malignant lymphoma produced lower than normal values, averaging 0.38 +/- 0.08 dB/cm/MHz.     

脂肪肝MRI同反相位定量测量与CT值相关分析

目的：分析脂肪肝MRI同反相位定量测量与CT值相关性,并评价MRI同反相位定量测量判断脂肪肝的价值。方法：回顾性分析86例临床疑诊脂肪肝而行CT、MRI检查病例,测量相应的CT值及同反相位上的MR信号,计算3个CT值比及4个信号指数。使用Pearson相关分析3个CT值比与4个信号指数间的相关性,并以CT值肝/脾≤1作为脂肪肝标准,计算不同阈值下信号指数判断脂肪肝的敏感性、特异性和准确性。结果：各CT值比与各信号指数间均呈明显负相关（r=-0.823～-0.917）,其中以CT值肝/脾与信号指数1之间的相关性最高（r=-0.917,P=0.000）。以CT值肝/脾≤1作为脂肪肝标准,判断脂肪肝时,信号指数1、信号指数4均以阈值≥0.1最佳,准确性分别为86.05%和89.53%。结论：CT值肝/脾与MRI同反相位定量测量有很好的相关性,两者都能作为脂肪肝定量评价的手段,并且能互为补充。以信号指数1或信号指数4≥0.1的标准诊断脂肪肝是合适的。