[The mechanism of inhibition of the increase in intracellular calcium concentration by the islet amyloid polypeptide in high glucose-stimulated INS-1 cells].

OBJECTIVE: To explore the potential mechanism of the inhibition of increased intracellular free calcium concentration ([Ca²âº]i) by short-term exposure to the islet amyloid polypeptide (IAPP) in high glucose-stimulated pancreatic ß cells. METHODS: The pancreatic ß cells were loaded with calcium sensitive fluorescent indicator Fluo-4/AM. The fluorescence intensity, which represented [Ca²âº]i, was measured in time by laser scanning confocal microscope before and after stimulated by glucose, KCl, caffeine and carbachol. RESULT: The fluorescence intensity F/F0 in INS-1 cells, increased to about 2 folds after glucose stimulation. After the exposure to the IAPP with different concentration, the fluorescence intensity F/F0 was decreased slightly in the pretreated cells by 16.7 mmol/L glucose with 0.5 µmol/L IAPP. However, after the pretreatment of IAPP with the concentration of 1.0, 5.0, 10.0 µmol/L, the fluorescence intensity F/F0 showed a dose-dependent decrease with statistical difference. The fluorescence intensity F/F0 in the cells increased rapidly in a peak pattern after the stimulation of 30 mmol/L KCl. But with the pretreatment of 10.0 µmol/L IAPP, the fluorescence intensity F/F0 decreased with statistical difference. With 20 mmol/L caffeine and 100 µmol/L carbachol which stimulated Ca²âº release respectively from internal ryanodine receptor (RYR) and inositol triphosphate (IP3) Ca²âº storage, the fluorescence intensity F/F0 curve presented a peak pattern. After 10 µmol/L IAPP pretreatment, the fluorescence intensity F/F0 showed no statistical difference from the control group. CONCLUSIONS: The short-term effect of IAPP on pancreatic ß cells has no influence on the caffeine and carbachol stimulated Ca²âº release from endoplasmic reticulum RYR and IP3 Ca²âº storage. The inhibition of calcium increase in INS-1 cells by short-term exposure to IAPP may mainly via inhibiting the voltage-gated L-calcium channels with intact release capacity of Ca²âº storage.

[Clinical application of 320-row computed tomography 4D digital subtraction angiography in hepatocellular carcinoma].

OBJECTIVE: To explore the application value of 320-row computed tomography (CT) 4D digital subtraction angiography (DSA) for hepatocellular carcinoma (HCC). METHODS: A total of 40 HCC patients received 320-row CT contrast scans. The 4D DSA images were obtained on the basis of baseline data. The normal anatomy and anatomical variations of hepatic artery, tumor supplying arteries, tumor vessels, tumor staining were observed by comparing DSA (n = 20). RESULTS: 320-row CT 4D DSA could show 6-7 levels of intrahepatic arterial branch. Normal hepatic artery anatomy was found in 35 cases (87.5%, Michels I type) and variations in 5 cases (12.5%). The diagnose accordance rate was 100% between 4D DSA and DSA in showing the anatomy and variation of hepatic artery. Among them, 320-row CT 4D DSA showed tumor staining (n = 40), tumor vessels (n = 28), tumor supplying arteries (n = 26) and two hepatic supplying arteries (n = 3). The number of tumor supplying arteries observed by 4D DSA (n = 20) was 18 versus 19 by DSA. Compared with DSA, the accurate rate of 4D DSA was 94.7% (18/19) in detecting tumor supplying arteries. CONCLUSION: As a noninvasive vascular examination modality, 320-row CT 4D DSA can accurately visualize normal anatomy and variation of hepatic artery, dynamically display tumor staining and reproducibly delineate the three-dimension relationship between tumor and blood vessels. In consistency with DSA in detection blood supply of HCC, 320-row CT 4D DSA provides a rapid, DSA-like and non-invasive alternative.

[To evaluate the role of OLT on splenomegaly of portal hypertension by the radiological changes of splenic morphology and collaterals].

OBJECTIVE: To explore the effect of orthotopic liver transplantation (OLT) on portal hypertension by observing the radiological changes of splenic volume and collaterals before and after OLT. METHODS: In our hospital 56 patients performing OLT due to cirrhosis, portal hypertension and splenomegaly were classified into five groups according to their following-up time: A (≤3 months), B (>3-6 months), C (>6-12 months), D (>12-24 months), and E (>24 months). Twenty health people were chose as control group (F). The splenic width, thickness, length, volume, diameter of portal and splenic vein and collaterals were measured and observed in every patient of six groups before and after OLT respectively. RESULTS: After OLT, the splenic volume decreased by 25.4%, 27.8%, 21.9%, 25.2%, 27.7% in five groups respectively, which was still larger than the normal group (P<0.05). Gastroesophageal varices in 31 cases (81.6%, 31/36) became normal after OLT. The opened umbilical vein disappeared and the retroperitoneal varices persisted in five cases after OLT. CONCLUSIONS: Splenomegaly and opened collaterals can be relieved by OLT effectively. The splenic volume didn't change obviously until it decreased by 25% in the three months after OLT. Gastroesophageal varices can be removed in most of patients after OLT. The splenomegaly could last paralled with the splenic vein and retroperitoneal varices after OLT. After OLT, correct disposal of splenic and collateral changes could improve the success rate and the long-term treatment effect of OLT.

[Application value of diffusion-weighted imaging in ischemic-type biliary lesions after liver transplantation].

OBJECTIVE: To discuss the application values of DWI (diffusion-weighted imaging) and ADC (apparent diffusion coefficient) on ischemic-type biliary lesions (ITBL) after orthotopic liver transplantation. METHODS: According to whether there was ITBL after liver transplantation or not, 46 cases of liver transplantation were selected and divided into 2 groups on the basis of PTC (percutaneous transhepatic cholangiography) or ERCP (endoscopic retrograde cholangiopancreatography) examination, pathology or clinical follow-up data: ITBL group (n = 29) and no ITBL group (C group, n = 17). The ADC value was measured for right lobe of graft liver parenchyma (b value = 600 s/mm(2)). And the signal of biliary system of graft on DWI and biliary tract on MRCP were analyzed. RESULTS: (1) The ADC values of liver graft were (1.456 ± 0.286) × 10(-3) mm(2)/s and (1.716 ± 0.391) × 10(-3) mm(2)/s in ITBL and C groups respectively. The difference in ADC value was significant between two groups (P = 0.015); (2) the incidence of increased signal of bile duct on DWI was 82.8% (24/29) and 5.9% (1/17) for ITBL and C groups respectively. The lesion was located in porta hepatis and intrahepatic small bile duct was seen in 17 of 24 patients (70.8%) in ITBL group. The difference was significant in signal of bile ducts between ITBL and C groups (P < 0.001). Twenty-one cases with sludge on DWI in ITBL group had hyperintensity, isointensity or hypointensity. There was no abnormal signal in the lumen of bile duct in C group. CONCLUSION: The major sign of ITBL is a hyperintensity of porta hepatis and small bile ducts on DWI. And the ADC value of graft liver parenchyma decreases. These reflect the pathological changes to an extent and may be an effective and sensitive monitoring tool of early ITBL. DWI is a novel, non-invasive, simple and practical method in the diagnosis and differential diagnosis of ITBL after liver transplantation.

[The effects of amylin on the islet beta-cells voltage-gated L-calcium channels in rats].

OBJECTIVE: To observe the effect of amylin on the islet beta-cells voltage-gated L-calcium channels in rats. METHOD: Patch clamp technique was employed in the observation of the features and changes of electric current of islet beta-cells voltage-gated L-calcium channels before and after using amylin. RESULTS: In the glucose environment of 5.5 mmol/L, the electric current of rat islet beta-cells voltage-gated L-calcium channels was activated at -40 mV and reached the peak at about +20 mV, with a peak value of about -120 pA and the insulin secretion level was (0.76 +/- 0.12) microg/L. Under the stimulation of glucose of 16.7 mmol/L, the peak current voltage moved to the left and increased up to - 140 pA and the level of insulin secretion measured (1.78 +/- 0.13) microg/L. Hatch islet beta-cells in amylin at the concentrations of 0.5, 1.0, 5.0 and 10.0 micromol/L, respectively. It was observed that in the 0.5 micromol/L and 1.0 micromol/L groups, there was no remarkable change in the peak potential activation voltage, current, and insulin secretion volume in comparison with the control group. However, in the environment of 5.5 mmol/L glucose, the increase of activation voltage of the 5.0 and 10.0 micromol/L groups was - 30 mV, with the peak current reduced to approximately -80 pA and -60 pA and the insulin secretion decreased to (0.49 +/- 0.11) microg/L and (0.36 +/- 0.12) microg/L respectively. Under the concentration of 16.7 mmol/L glucose, the activation voltage increased from -40 mV up to -30 mV and the peak current reduced to -80 pA and -40 pA. In the meantime, the insulin secretion decreased respectively to (1.20 +/- 0.13) microg/L and (0.89 +/- 0.14) microg/L, which is of significance. CONCLUSION: The secretion of insulin is synchronized with the opening of the islet beta-cells voltage-gated L-calcium channels at the stimulation of glucose. The amylin inhibition of the insulin secretion is also synchronized with the opening of islet beta-cells voltage-gated L-calcium channels and it's in a positive concentration-dependent manner.

[Diagnostic value of multislice spiral CT and MRI in detection of tumor recurrence after liver transplantation for hepatocellular carcinoma].

OBJECTIVE: To investigate the manifestation and diagnostic value of multislice spiral CT (MSCT) and MRI imaging in detection of tumor recurrence after liver transplantation for hepatocellular carcinoma (HCC). METHODS: The clinical data of 161 consecutive HCC patients who underwent orthotopic liver transplantation were retrospectively reviewed. Twenty-nine HCC patients were classified by pTNM according to the "Pittsburgh criteria". MSCT and MRI findings of tumor recurrence after liver transplantation were evaluated retrospectively in 29 stage II-IVb HCC patients. The recurrence site and relapse interval between liver transplantation and recurrence were analyzed. RESULTS: Lung tumor recurrence were found in 21 cases, presented as cotton-like lesions in a diameter of 2 - 3 cm, with a clear margin and homogeneous density. Pleural tumor recurrence was detected in 4 cases. Liver tumor recurrence were found in 9 cases, which can be divided into four subtypes: multinodular in 4 cases, diffuse lesion in 2 cases, huge mass in 2 cases, and uninodular in 1 case. Two cases showed tumor thrombus in the inferior vena cava and portal vein. Lymph node tumor recurrence was found in 9 cases, presented as multiple nodules at hepatic hilum, lesser peritoneal sac, posterior mediastinum, retroperitoneum, or around pancreatic head, and accompanied with merging and necrosis in one case. Bone tumor recurrence were found as osteolytic destruction in 4 cases, and accompanied with adjacent soft-tissue mass in 2 cases. The recurrence sites of the 29 cases were as following: lung (21 cases, 72.4%), liver (9 cases, 31.0%), lymph nodes (9 cases, 31.0%), bone (4 cases, 13.8%) and other sites (3 cases, 10.3%). Lung tumor recurrence was found in all the 10 stage IVb patients with tumor recurrence after liver transplantation, significantly more frequent than that in stage IVa patients (P = 0.023). After liver transplantation, all 25 patients with stage III approximately IVb HCC developed recurrence within one year, but in the 4 cases with stage II HCC at one year later (P = 0.009). CONCLUSION: The results of our study show that in hepatocellular carcinoma patients after liver transplantation, the lung and pleura are the most frequent site of recurrence, followed by liver, lymph node and bone as the second and third sites. The Stage IVb hepatocellular carcinoma should be regarded as a contradiction for liver transplantation due to rapid recurrence. Tumor recurrence occurs later in stage II HCC than in stage III approximately IVb patients. MSCT and MRI are of significant importance in diagnosis and formulating operation plan in HCC patients with recurrence after liver transplantation.

Selection of the most powerful predictors for the evaluation of hepatic steatosis grade: an experimental study.

PURPOSE: To select the most powerful predictors for the evaluation of hepatic steatosis grade. METHODS AND MATERIALS: Forty-five healthy New Zealand rabbits were randomly divided into one normal control group and three experimental groups. Hepatic steatosis models were established by feeding a high-fat, high-sugar diet and drinking water containing 5% ethanol. Twenty-two variable indexes were measured using general observation, biochemical examination, ultrasonography, computed tomography (CT), and proton magnetic resonance spectroscopy (MRS). Univariate analysis, correlation analysis, and stepwise regression analysis were used to make the selection of the most powerful predictors. ROC analysis was used to compare the diagnostic efficacy of single index with combined index (Y) expressed by a regression equation. RESULTS: Based on statistical analysis, there were 12 variable indexes with significant differences among groups, which correlated with hepatic steatosis grade: liver weight, hepatic index, liver CT value, liver-to-muscle attenuation ratio, 1H MRS fat peak value, fat peak area, fat-to-water peak area ratio, fat percentage, ultrasound attenuation coefficient, serum aspartate aminotransferase, total cholesterol (TC) and triglycerides. Among them hepatic index, liver CT value and serum TC were selected as the most powerful predictors for hepatic steatosis grade with correlation coefficients of 0.709, -0.764, and 0.886, respectively. The regression equation was: Y=1.975 + 3.906 x 10(-2)X1 + 0.369X2-2.84 x 10(-2)X3, where Y=hepatic steatosis grade, X1=TC, X2=hepatic index, and X3=liver CT value. ROC analysis displayed PPV, NPV, curve area of combined index (Y) were superior to simple index (hepatic index, liver CT value and serum TC) in evaluating hepatic steatosis grade, and they were nearly 1.0000, 1.0000 and 1.000, respectively. CONCLUSIONS: Combined application of several diagnostic methods is superior to simple diagnostic method, and could provide comprehensive, rapid, accurate evaluation of hepatic steatosis grade.

[Inhibitory effect of unaggregated amyloid beta protein (25-35) on delayed rectifier potassium current in rat hippocampal CA3 pyramidal neurons].

OBJECTIVE: To investigate the effect of unaggregated Abeta(25.35) on delayed rectifier potassium current (I(K)) in neonatal rat hippocampal CA3 pyramidal neurons. METHODS: The rat hippocampal neurons were enzymatically isolated from 10-11-day-old Wistar rat. The I(K) was recorded using whole-cell patch clamp technique. RESULTS: The inhibitory effect of unaggregated Abeta(25-35) on I(K) was time-dependent, because I(K) significantly decreased from (6.987 +/- 1.152) nA to (2.540 +/- 0.349) nA after adding unaggregated Abeta(25-35) and reached a stabilized level after 5-7 min (n = 8, P <0.01). However, the inhibitory effect was not concentration-dependent, because the decrease of the I(K) amplitude in different concentration groups were all around 60%. Unaggregated Abeta(25-35) also remarkably affected the half-activation potential, which was (4.114 +/- 0.730) mV and (-5.463 +/- 0.950) mV before and after its application (n = 15, P <0.05); however, the slope factor of activation curve was not significantly changed. CONCLUSION: The inhibitory effect of unaggregated Abeta(25-35) on I(K) may be a possible mechanism involved in the pathogenesis of Alzheimer's disease.

Portalsystemic hemodynamic changes in chronic severe hepatitis B: An ultrasonographic study.

AIM: To evaluate portalsystemic hemodynamic changes in chronic severe hepatitis B. METHODS: Hemodynamic parameters included portal vein diameter (PVD), portal vein peak velocity (PVPV), portal vein volume (PVV), spleen length (SPL), spleen vein diameter (SPVD), spleen vein volume (SPVV) and umbilical vein recanalization. They were measured by Color Doppler ultrasonography in 36 patients with chronic severe hepatitis B, compared with 51 normal controls, 61 patients with chronic hepatitis B, 46 patients with compensable cirrhosis, and 36 patients with decompensable cirrhosis. RESULTS: In the group of chronic severe hepatitis B, PVD (12.38 +/- 1.23 mm) was significantly different from the normal control, compensable cirrhosis and decompensable cirrhosis groups (P = 0.000-0.026), but not significantly different from the chronic hepatitis group. PVPV (16.15 +/- 3.82 cm/s) dropped more significantly in the chronic severe hepatitis B group than the normal control, chronic hepatitis B and compensable cirrhosis groups (P = 0.000-0.011). PVV (667.53 +/- 192.83 mL/min) dropped significantly as compared with the four comparison groups (P = 0.000-0.004). SPL (120.42 +/- 18.36 mm) and SPVD (7.52 +/- 1.52 mm) were longer in the normal control and chronic hepatitis B groups (P = 0.000-0.009), yet they were significantly shorter than those in the decompensable cirrhosis group (P = 0.000). SPVV (242.51 +/- 137.70 mL/min) was also lower than the decompensable cirrhosis group (P = 0.000). The umbilical vein recanalization rate (75%) was higher than the chronic hepatitis B and compensable cirrhosis groups. In the course of progression from chronic hepatitis to decompensable cirrhosis, PVD, SPL and SPVD gradually increased and showed significant differences between every two groups (P = 0.000-0.002). CONCLUSION: Patients with chronic severe hepatitis B have a tendency to develop acute portal hypertension, resulting in significantly reduced portal vein perfusion. Observation of the portalsystemic hemodynamic changes may be contributed to the disease progression of chronic liver disease.

[Effects of beta-cypermethrin on voltage-gated potassium channels in rat hippocampal CA3 neurons].

The effects of beta-cypermethrin (consisting of alpha-cypermethrin and theta-cypermethrin) on the transient outward potassium current (I(A)) and delayed rectifier potassium current (I(K)) in freshly dissociated hippocampal CA3 neurons of rats were studied using whole-cell patch-clamp technique. The results indicated that alpha-cypermethrin increased the value of I(A) and theta-cypermethrin decreased the value of I(A), though both of them shifted steady activation curve of I(A) towards negative potential. theta-cypermethrin contributed to the inactivation of I(A). The results also showed that alpha-cypermethrin and theta-cypermethrin decreased the value of I(K), and shifted the steady state activation curve of I(K) towards negative potential. Both alpha-cypermethrin and theta-cypermethrin had no obvious effects on the inactivation of I(K). theta-cypermethrin prolonged recovery process of I(K). These results imply that both transient outward potassium channels and delayed rectified potassium channels are the targets of beta-cypermethrin, which may explain the mechanism of toxical effects of beta-cypermethrin on mammalian neurons.