[The detecting value of virtual non-calcium technique of dual-energy CT for bone marrow edema around nontraumatic osteonecrosis of the femoral head]

Objective: To evaluate the value of virtual non-calcium (VNCa) technique of dual-energy CT (DECT) for detecting bone marrow edema (BME) around nontraumatic osteonecrosis of the femoral head (ONFH) using MRI as reference standard. Methods: Nontraumatic ONFH patients were prospectively studied in the Fourth Medical Center of Chinese PLA General Hospital from October 2022 to May 2023, and their MRI and DECT images were analyzed. The diagnostic efficiency of the subjective assessment of BME around ONFH by two radiologists in VNCa color-coded images were calculated using the MRI results as the reference standard. The BME ranges were compared between VNCa images and MRI. Traditional CT values and VNCa CT values were compared between normal bone marrow and BME. The receiver operator characteristic (ROC) curve was established based on the statistically different CT values, and the area under the curve (AUC) was calculated to find the threshold to distinguish normal bone marrow from BME and evaluate the diagnostic efficacy. Results: Thirty patients with ONFH were included, including 24 males and 6 females, aged (39±12) years. There were 18 bilateral hips and 12 unilateral hips, with a total of 48 hips, 34 hips of which showed BME on MRI. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of subjective detection of BME on VNCa color coded maps by two physicians were 97.1% (33/34) and 97.1% (33/34), 92.9% (13/14) and 71.4% (10/14), 97.1% (33/34) and 89.2% (33/37), 92.9% (13/14) and 90.9% (10/11), 95.8% (46/48) and 89.6% (43/48), respectively, with no statistical difference (all P>0.05).There was no statistical difference between VNCa color-coded images and MRI in the BME range (P=1.160). The traditional CT values measured by the two radiologists were in good agreement with VNCa CT values, with intraclass correlation coefficient (ICC) of 0.948 (95%CI: 0.908-0.971) and 0.982 (95%CI: 0.969-0.990), respectively. The traditional CT value of normal bone marrow was (400.7±82.8) HU, and that of BME was (443.7±65.7) HU, with no statistical difference (P=0.062). The VNCa CT value of normal bone marrow was (-103.1±27.8) HU, and that of BME was (-32.9±25.7) HU, with statistical difference (P<0.001). The AUC of distinguishing normal bone marrow from BME based on VNCa CT value was 0.958 (95%CI: 0.857-0.995). The best cut-off value was -74.5 HU, and when the VNCa CT value was higher than -74.5 HU, the sensitivity, specificity, PPV, NPV and accuracy of diagnosing BME were 97.1%, 92.9%, 97.1%, 92.9% and 95.8 %, respectively. Conclusion: The VNCa technique of DECT has high efficiency in detecting BME around ONFH, and can accurately demonstrate the range of BME.

[Application of Rotarex catheter system in femoropopliteal artery stenosis accompanied with thrombosis]

OBJECTIVE

To evaluate the effectiveness and safety of Rotarex catheter system in treating femoropopliteal artery stenosis accompanied with thrombosis.

METHODS

From Jun. 2017 to Dec. 2019, the clinical data of 32 femoropopliteal artery stenosis accompanied with thrombosis cases treated with Rotarex catheter system were retrospectively analyzed. There were 23 males and 9 females aged from 50 to 89 years and the mean age was (70.7±10.3) years. Six cases had acute course of disease (≤2 weeks), 17 cases had subacute course of disease (>2 weeks, ≤3 months), and 9 cases had chronic course of disease (>3 months). Mean lesion length was (23.4±13.7) cm, mean occlusion length was (19.9±13.3) cm, and in-stent occlusion 7 cases. The superficial femoral artery (SFA) was involved in 13 cases, the popliteal artery (PA) was involved in 8 cases, and both SFA and PA were involved in the other 11 cases. All the cases were treated with Rotarex catheter system. When necessary, suction with large lumen catheter was enabled. Residual stenosis was treated with percutaneous transluminal angioplasty (PTA). Drug-coated balloon (DCB) was only used in patients with financial status, and stent was used only when it was necessary. Heparin was used for 24 h after procedures, and after that, antiplatelet agents were used. Doppler ultrasonography was taken during the followed-up.

RESULTS

Technical success was 100%, and mean procedure time was (107.4±21.5) min. 8F (1F≈0.33 mm) and 6F Rotarex catheter were used in 27 and 5 cases respectively. In 27 cases, forward flow was obtained immediately after debulking with Rotarex catheter, and in the other 5 cases, suction with large lumen catheters were used. PTA was used in all 32 cases. DCB were used in 8 cases, of which 4 were used in in-stent stenosis. Twelve cases were implanted stents. There were no perioperative deaths. The only one procedure related complication was distal embolism. We took out the thrombus with guiding catheter. In all cases, mean hospital stay were (4.6±1.5) d. The ankle brachial index increased from 0.32±0.15 to 0.86±0.10 after treatment (t=-16.847, P < 0.001). The Rutherford stages decreased significantly (Z=-4.518, P < 0.001). All the patients were followed up for 6.0-36.0 months, and the median time was 16.0 months. 2 cases stopped antiplatelet agents, which resulted in acute thrombosis. Another percutaneous mechanical thrombectomy and PTA were taken in one of them. Two cases died of cardiovascular disease during the follow-up, and no amputation was observed. Target lesion restenosis occurred in 7 cases during the follow-up, and target lesion revascularization (TLR) was taken in two of them.

CONCLUSION

In treating femoropopliteal artery stenosis accompanied with thrombosis, Rotarex catheter can remove thrombus effectively, and that can expose underlying lesions and reduce stent use and complications rates. It is a safe and effective method.

[Application of mechanical debulking in arteriosclerosis occlusive disease of lower extremity]

Objective: To evaluate the effect of mechanical debulking in treating arteriosclerosis occlusive disease of lower extremity. Methods: The clinical data of 52 arteriosclerosis occlusive disease of lower extremity cases treated with Rotarex mechanical debulking system from June 2017 to June 2020 at Department of Intervention Vascular Surgery,Peking University Third Hospital were retrospectively analyzed. There were 37 males and 15 females,aged(69.4±10.1)years(range:47 to 89 years).Lesion length was (21.6±12.9)cm(range:4 to 45 cm),occlusion length was (18.5±11.8)cm(range:4 to 45 cm).The lesion was located in iliac artery(IA) in 6 cases,femoral-popliteal artery(FPA) in 42 cases,and both IA and FPA in 4 cases. All the cases were treated with Rotarex mechanical debulking system. Residual stenosis more than 50% were treated with percutaneous transluminal angioplasty(PTA).Drug coated balloon was used in part of them,and stent was used only when it was necessary. The patient's operation, complications, postoperative target vessel restenosis and reoperation were collected. The paired sample t test and rank sum test was used for data comparison and the postoperative target vessel patency rate was analyzed by Kaplan-Meier survival curve. Results: All the 52 cases obtained technical success. Percutaneous transluminal angioplasty was used in all cases,and drug coated balloon were used in 11 cases. Twenty-six stents were implanted in 24 cases (2 cases implanted 2 stents).Nine stents were implanted in IA and 15 in FPA. The length of stents was (11.3±3.3)cm(range:6 to 23 cm).There were 3 procedure related complications: one of them was acute occlusion in an iliac lesion,and thrombectomy was applied urgently,and the result was good. And the other two were distal embolism. The thrombus were took out with guiding catheter. The hospital stay was (4.8±1.9)days. The ankle brachial index increased from 0.34±0.16 to 0.81±0.16 after treatment(t=-25.160,P<0.01).The Rutherford stages decreased from (M(IQR)) 3(1) to 1(1(Z=-6.825,P<0.01).The median followed up time was 19 months(range:6 to 42 months).Two cases stopped antiplatelet agents during follow-up and which result in acute thrombosis 2 weeks and 2 months later respectively. One of them was treated with percutaneous mechanical thrombectomy and the other one was not for gastrointestinal hemorrhage. Four cases died during follow-up,one case died of lung cancer,one died of abdominal infection,and the other 2 cases died of cardiovascular disease,and no amputation was observed. Target lesion restenosis(TLR) more than 50% occurred in 13 cases during the follow-up. All TLR were observed in FPA,and target lesion revascularization was taken in 3 of them. According to Kaplan-Meier survival curve analysis,half-year,1-year and 2-year cumulative patency rates of target vessels in this group was 94.2%,87.4% and 51.4%, respectively. And half-year and 1-year cumulative patency rates just in FPA cases was 92.9% and 84.3%, respectively. Conclusions: Percutaneous mechanical debulking using Rotarex catheter combining PTA can reduce the use of stents in femoral-popliteal artery. It is safe and effective in treating with arteriosclerosis obliterans of lower extremity.

[Artificial intelligence evaluation of simulated phantom lung nodules with different pre-adaptive iteration techniques]

Objective: To investigate the detection rate of pulmonary nodules and the accuracy of automated measurement in chest simulation phantom by artificial intelligent computer-aided detection of pulmonary nodules with different pre-adaptive iterative techniques (ASIR-V) in wide-spectrum CT scanning. Methods: Sixteen pulmonary nodules with different diameters, densities and shapes were placed in the chest simulation phantom from December 2017 to March 2018. The weight of ASIR-V was set at 0%, 20%, 30%, 40% and 50% respectively by using Revolution CT broadband energy spectrum scanning protocol. Spearman correlation analysis was used to analyze the dose volume CT dose index (CTDIvol) and dose length product (DLP) of each group. Scanning data were imported into Tuma Shenwei artificial pulmonary nodule analysis software to evaluate the nature of the detected nodules, and ICC was used to detect the differences among groups. Results: With the increase of ASIR-V weight, the effective dose of patients decreased gradually. CTDIvol of five groups of radiation dose volume CT dose index was 7.93, 7.24, 5.85, 5.15, 3.76 mGy,dose-length product DLP was 379, 346, 280, 246, 179 mGy·cm.There was a linear negative correlation between ASIR-V weights and CTDIvol as well as DLP, r value was-0.969, P<0.01.There was no significant difference in the detection rate of pulmonary nodules between AI and physicians (P>0.05). There was high intraclass correlation coefficients for the diameter, volume, CT value and malignant percentage of pulmonary nodules (ICCs:0.981-1.000). Conclusions: Radiation dose of unenhanced chest CT scan using wide detector spectral imaging decreased with the increasing of preset ASIR-V. Lung nodule detection rate and evaluation performance can be maintained well by using ASIR-V reconstructions at lower radiation dosage.

[Prognostic value of pretreatment (18)F-FDG PET-CT for patients with advanced diffuse large B-cell lymphoma]

Objective: To investigate the prognostic value of the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) measured by pretreatment (18)F-FDG PET-CT in patients with stage Ⅲ~Ⅳ diffuse large B-cell lymphoma (DLBCL). Methods: Clinical data of 72 DLBCL patients with stage Ⅲ~Ⅳ disease undergoing a pretreatment PET-CT scan were retrospectively analyzed. SUVmax, MTV and TLG values of whole-body tumor were calculated from PET-CT images with a threshold of SUVmax 40% of tumor tissues. The optimal cutoff lines of SUVmax, MTV and TLG were obtained by ROC curve analysis. The Kaplan-Meier method and Log-rank test were used to perform univariate survival analysis, while Cox proportional hazards model was done for multivariate analysis. Results: The SUVmax, MTV and TLG of 72 patients were 21.64, 139.48 cm(3) and 1 413.77, respectively. The areas under the ROC curve (AUC) of SUVmax, MTV and TLG were 0.411 (95%CI=0.279~0.544, P=0.195), 0.688 (95%CI=0.566~0.811, P=0.006) and 0.526 (95%CI= 0.469~0.672, P=0.123), respectively. The median SUVmax (21.64) and TLG(1 413.77) were used as the cutoff lines due to smaller AUC. The cutoff point of MTV was 69.71 cm(3). For DLBCL patients of stage Ⅲ~Ⅳ disease, univariate analysis showed that SUVmax and TLG were not associated with the progression-free survival (PFS) and overall survival (OS) (P>0.05 for all). Multivariate analysis showed that National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) but not MTV was the independent prognostic predictor of PFS and OS (P<0.05 for all). And MTV was not the independent prognostic factor of PFS and OS for stage Ⅲ DLBCL (P>0.05 for all). Conclusions: For DLBCL patients with stage Ⅲ~Ⅳ disease, the prognostic value of SUVmax, MTV and TLG before treatment initiation are undetermined, and these indices cannot be used to predict the prognosis.

[Evaluate the value of (18)F-FDG PET-CT imaging in predicting the mutationsin epidermal growth factor receptor in lung adenocarcinoma]

Objective: To investigate the value of maximum Standardized Uptake Value(SUVmax), Metabolic Tumor Volume (MTV) and Total Lesion Glycolysis (TLG) calculated from (18)F-FDG PET-CT in predicting the presence of epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma. Methods: We retrospectively reviewed 137 lung adenocarcinoma patients with EGFR mutations testing and pretreatment (18)F-FDG PET-CT. Receiver Operating Characteristic (ROC) curve analysis was performed to quantify the predictive value of SUVmax、MTV、TLG. A multivariate logistic regression analysis was used to evaluate the predictive value of EGFR mutation. Results: Among 137 lung adenocarcinoma patients, 86(62.8%, 86/137) were identified with EGFR mutations. The SUVmax, MTV and TLG were 7.4, 5.28 cm(3,) 20.20, respectively. The optimal cut-off values of SUVmax, MTV and TLG were 7.99(AUC=0.658, 95% CI=0.566~0.752, P=0.002), 6.09 cm(3)(AUC=0.644, 95% CI=0.550~0.737, P=0.005), 35.08(AUC=0.650, 95% CI= 0.557~0.744, P=0.003), respectively. Multivariate analysis showed that TLG and smoking status were the most significant predictors of EGFR mutation(all P<0.05). Conclusion: TLG in (18)F-FDG PET/CT is an independent factor for predicting EGFR mutation in patients with lung adenocarcinoma, and has certain reference value for predicting EGFR mutation.

[The relationship between (18)F-FDG PET/CT metabolic parameters and clinicopathological features of breast cancer]

Objective: To investigate the relationship between metabolic parameters of primary lesion and clinicopathological features of patients with breast cancer. Methods: Clinical data of 78 patients with breast cancer undergone (18)F-FDG PET/CT before surgery was retrospectively analyzed. SUVmax, SUVmean and metabolic tumor volume (MTV) of primary lesions were measured by horizontal, sagittal and coronal position volume section with a threshold of 40% SUVmax. TLG was calculated and the highest SUVmax among metastatic lymph nodes was measured. Results: SUVmax, SUVmean, MTV, TLG and the maximum diameter of 78 primary lesions were 6.64(1.85, 22.79), 3.88(1.30, 11.42), 13.36(1.66, 129.08)cm(3,) 47.92(2.85, 443.28)g and 2.35(1.23, 9.80)cm, respectively. SUVmax of metastatic lymph node was 5.12(2.38, 14.32). There were statistically significant differences of primary lesion metabolic parameters (SUVmax, MTV, TLG) in different pathological stages, T stages, with or without lymph node invasion (all P<0.05). Only TLG of ER negative patients was higher than that of ER positive patients (P<0.05). TLG, MTV of PR negative patients were higher than that of PR positive patients (both P<0.05). No significant differences of metabolic parameters were found between HER-2 negative and positive patients (all P>0.05). SUVmax, MTV, TLG of primary lesion were positively associated with Ki-67 and the maximum diameter (all P<0.05), and the correlation coefficient of TLG was the highest. SUVmax, SUVmean, MTV and TLG were all positively associated with T stage (all P<0.05), and the correlation coefficient of TLG was the highest. None of the parameters had correlation with N stage(all P>0.05). Only TLG had positive correlation with clinical stage (P<0.05). SUVmax of metastatic lymph node was positively associated with metabolic parameters of primary lesion, T stage and clinical stage, respectively (all P<0.05). Conclusions: (18)F-FDG PET/CT metabolic parameters, especially TLG has the highest correlation with clinicopathological features of breast cancer. SUVmax of metastatic lymph node was positively associated with metabolic parameters of primary lesion and clinical stage.

[Significance of renal filtration fraction evaluation of renal artery stenting for atherosclerotic renal artery stenosis treatment]

OBJECTIVE

To investigate the significance of filtration fraction (FF) and renal artery stenting in the treatment of atherosclerotic renal artery stenosis.

METHODS

In the study, 42 cases of renal artery stenosis were treated with 52 renal artery stent implantation. Percutaneous transluminal renal angioplasty and stent (PTRAS) of the patients' health side kidney, ipsilateral kidney (renal) glomerular filtration rate (GFR), renal effective renal plasma flow effective renal plasma flow (ERPF), kidney filtration fraction changes of preoperative and postoperative serum creatinine (SCR) and the changes in the patients with blood pressure (SBP) and the changes after taking antihypertensive drugs were observed and analyzed.

RESULTS

The 52 cases of renal artery stent implantation were all successful. Preoperative ipsilateral GFR was significantly lower than that of normal side (t=-3.989, P=0.000); preoperative ipsilateral ERPF was significantly lower than the contralateral side (t=-4.926, P=0.000). On both sides, the overall FF values were equal (t=1.273, P=0.207). Postoperative ipsilateral renal GFR was increased, but there was no statistical difference (t=-1.411, P=0.164). Postoperative ipsilateral renal ERPF was increased significantly (t=-4.954, P=0.000), and FF lower (closer to the normal value (t=3.274, P=0.002). Postoperative side GFR was significantly reduced (t=2.569, P=0.000), the contralateral ERPF was significantly reduced (t=3.889, P=0.001), and FF had no significant change (t=-0.758, P=0.454). Postoperative side GFR was lower than that of the contralateral (t=-3.283, P=0.002) and postoperative side ERPF was still lower than that of the contralateral (t=-3.351, P=0.001), but on both sides, the FF values were equal (t=-0.361, P=0.719). Preoperative FF was relatively normal in the patients with kidney, and the postoperative FF value change was small (t=0.799, P=0.430); preoperative FF was significantly higher in the patients with kidney, and the postoperative FF value was lower than the preoperative (normal value, t=5.299, P=0.000). Postoperative overall serum creatinine was significantly decreased (t=2.505, P=0.016); but for the patients with unilateral renal artery stenosis, the changes in serum creatinine had no statistical difference (t=1.228, P=0.299); and for the patients with bilateral renal artery stenosis and serum creatinine compared with the preoperative, the changes were decreased significantly (t=2.518, P=0.030); postoperative blood pressure (SBP) was significantly decreased compared with that before operation (t=8.945, P=0.000); antihypertensive drugs taken were decreased significantly compared with the preoperative (t=5.280, P=0.000).

CONCLUSION

For the patients with renal artery stenosis, FF is a useful index to understand the pathophysiological process of renal ischemia. Whether preoperative FF is significantly increased or FF is relatively normal, should be regarded as the indications of renal artery stent implantation.

[Randomized controlled trial to superficial femoral artery recanalization for lower extremity arteriosclerosis obliterans]

OBJECTIVE

To evaluate the safety and effectiveness of neglecting superficial femoral artery (SFA) recanalization for chronic lower extremity arteriosclerosis obliterans (ASO).

METHODS

Thirty-six cases treated for severe stenosis or occlusion of superficial femoral artery resulted from ASO were randomly divided into 2 groups. Twenty of them were treated by endovascular reconstruction of superficial femoral artery and the other 16 cases were not treated with their superficial femoral artery, but were only treated with the accompanied iliac and/or profunda femoral artery lesion.

RESULTS

There was no significant difference between the two groups on mean age, gender, ABI before treatment, accompanied diseases, Rutherford classification and trans-atlantic inter-society consensus (TASC) classification (P>0.05).One week after operation, the reconstruction group had better marked effect and total effective rate [75.0% vs.12.5%(P<0.001); 90.0% vs. 37.5%(P=0.001)] and lower no effective rate [10.0% vs. 62.5%(P=0.001)], There was no significant difference between the two groups on effective rate [15.0% vs. 25.0%(P=0.675)]. The deteriorate cases in both groups were zero, and there was no morbidity of complications and death in both groups during the perioperative period. In the 3-month follow up, the reconstruction group had a better marked effect rate [65.0% vs.25.0%(P=0.017)];There was no significant difference between the two groups on the effective rate, no effective rate and total effective rate [20.0% vs.43.8%(P=0.124); 15.0% vs.31.3%(P=0.422); 85.0% vs.68.8%(P=0.422)]. The deteriorate cases and morbidity of complications and death in both groups during the perioperative period were still zero. In the 6- and 12-month follow ups, there were no significant differences between the two groups on marked effect and total effective rate [60.0% vs.37.5%(P=0.180), 80.0% vs.87.5%(P=0.672); 60.0% vs.43.8%(P=0.332), 85.0% vs.87.5% (P=1.000)]. The deteriorate case was zero in both groups, and there was no morbidity of complications and death in both groups. The limb salvage rate in both groups was 100% during the whole follow up period. The reconstruction group had a higher cost[(53 367.4±24 518.3) yuan vs.(30 397.5±15 354.4) yuan(P=0.011)]. There were 8 cases of SFA restenosis/ reocclusion during the follow up,three of which accepted another endovascular treatment, and the reoperation rate was 15.0%. while in the nonreconstruction group, there was no case that needed another endovascular therapy, and the reoperation rate was zero.

CONCLUSION

Only dealing with accompanied iliac and profunda artery lesion and neglecting superficial femoral artery reconstruction is a safe, effective and inexpensive therapy for chronic lower extremity arteriosclerosis obliterans, and should be the preferred alternative for some patients.

Pressure Induced Stripe-Order Antiferromagnetism and First-Order Phase Transition in FeSe

To elucidate the magnetic structure and the origin of the nematicity in FeSe, we perform a high-pressure ^{77}Se NMR study on FeSe single crystals. We find a suppression of the structural transition temperature with pressure up to about 2 GPa from the anisotropy of the Knight shift. Above 2 GPa, a stripe-order antiferromagnetism that breaks the spatial fourfold rotational symmetry is determined by the NMR spectra under different field orientations and with temperatures down to 50 mK. The magnetic phase transition is revealed to be first-order type, implying the existence of a concomitant structural transition via a spin-lattice coupling. Stripe-type spin fluctuations are observed at high temperatures, and remain strong with pressure. These results provide clear evidence for strong coupling between nematicity and magnetism in FeSe, and therefore support a universal scenario of magnetic driven nematicity in iron-based superconductors.

[Prognosis of embolization of internal iliac artery during the endovascular repair for abdominal aortic aneurysm]

OBJECTIVE

To study the importance of the internal iliac artery (IIA) during the endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA).

METHODS

Forty-six consecutive cases of AAA treated by EVAR were retrospectively analyzed. The complications after exclusion of the IIA were analyzed.

RESULTS

The bilateral IIAs were reserved in 18 cases, in which the follow-up was achieved in 16 cases and no complication was observed. The IIAs were excluded in 28 (60.9%) cases, in which the bilateral, right and left IIAs were excluded in 7 (15.2%), 14 (30.4%) and 7 (15.2%) cases respectively. The follow-up was achieved in 26 cases. Buttock claudication was observed in 12 (46.2%) cases, altered bowel habit was observed in 8 (32.0%) cases, erectile dysfunction was observed in 3 (12.0%) cases, and bloody stool was observed in 2 (8.0%) cases. Comparing the bilateral and unilateral IIA exclusions, the rates of buttock claudication were 50.0% vs. 45.0%, altered bowel habit 33.3% vs. 31.6%, and erectile dysfunction 33.3% vs. 5.3% respectively. And the average duration of buttock claudication of bilateral IIAs exclusion (8.3 months) was longer than that of unilateral exclusion (4.7 months). Moreover, comparing the left and right IIA exclusions, the rates of buttock claudication were 57.1% vs. 38.5%, altered bowel habit 57.1% vs. 16.7%, and bloody stool 28.6% vs. 0 respectively. And the average duration of buttock claudication of left IIA exclusion (6.0 months) was longer than that of right exclusion (3.7 months).

CONCLUSION

The IIAs, especially the left IIA, should be reserved during the EVAR for AAA.

Broad-complex, but not ecdysone receptor, is required for progression of the morphogenetic furrow in the Drosophila eye

The progression of the morphogenetic furrow in the developing Drosophila eye is an early metamorphic, ecdysteroid-dependent event. Although Ecdysone receptor-encoded nuclear receptor isoforms are the only known ecdysteroid receptors, we show that the Ecdysone receptor gene is not required for furrow function. DHR78, which encodes another candidate ecdysteroid receptor, is also not required. In contrast, zinc finger-containing isoforms encoded by the early ecdysone response gene Broad-complex regulate furrow progression and photoreceptor specification. br-encoded Broad-complex subfunctions are required for furrow progression and proper R8 specification, and are antagonized by other subfunctions of Broad-complex. There is a switch from Broad complex Z2 to Z1 zinc-finger isoform expression at the furrow which requires Z2 expression and responds to Hedgehog signals. These results suggest that a novel hormone transduction hierarchy involving an uncharacterized receptor operates in the eye disc.

Oxidized low-density lipoproteins inhibit endothelial cell proliferation by suppressing basic fibroblast growth factor expression

BACKGROUND

Hyperlipidemia inhibits proliferation of endothelial cells (ECs) in culture and angiogenesis in vivo and in arterial explants. Elucidation of the mechanisms may suggest novel therapies against atherosclerosis.

METHODS AND RESULTS

Basic fibroblast growth factor (bFGF) expression and mitogenic effects were assessed in bovine aortic ECs incubated with oxidized LDL (ox-LDL). Compared with native LDL and lipoprotein-free controls, ox-LDL reduced bFGF mRNA levels in a time- and concentration-dependent manner, 100 microg/mL producing a maximum reduction of 40% to 50% within 24 to 48 hours. There were commensurate reductions in intracellular and extracellular bFGF concentrations, DNA and total RNA syntheses, and cell replication. FGF receptor 1 and beta-actin mRNA levels were unchanged. Ox-LDL accelerated bFGF mRNA degradation in actinomycin D-treated cells. However, inhibition of bFGF expression by ox-LDL was attenuated by cyclohexamide, indicating a requirement for continuous new protein synthesis for posttranscriptional destabilization. Reduced syntheses of DNA and total RNA were completely restored by bFGF but not by vascular endothelial growth factor. Inhibition of total RNA synthesis achieved by exposing cells to a bFGF-neutralizing antibody was similar in magnitude to that induced by ox-LDL.

CONCLUSIONS

Cytotoxic effects of ox-LDL on ECs are attributable in part to suppression of bFGF expression.

Transactivation of the human MDR1 gene by hepatitis B virus X gene product

BACKGROUND/AIMS

Persistent hepatitis B virus (HBV) infection may cause hepatocellular carcinoma. Patients with hepatocellular carcinoma are characterized by nonresponsiveness to chemotherapeutic agents. While many studies have been devoted to understanding the hepatocarcinogenesis mechanism of HBV, the possible relationship between HBV and the drug sensitivity phenotype of cancer cells has rarely been addressed. The hepatitis B virus X gene encodes a transcription transactivator which has been suggested to be a potential factor in viral hepatocarcinogenesis. The role of HBV pX in mediating the drug resistance phenotype of hepatoma cell lines was examined in this study.

METHODS

Standard transfection and chloramphenicol acetyltransferase assay were utilized to examine the effect of HBV pX transactivator on a reporter gene under the control of the human multidrug resistance (MDR) 1 upstream regulatory elements. Selected Hep G2 clones with or without HBV pX expression were tested for their sensitivity towards various anti-cancer agents by utilization of MTT assay.

RESULTS

The expression of HBV pX in both Hep G2 (p53+) and Hep 3B (p53-) cells resulted in transactivation of the reporter gene under control of the human MDR1 upstream regulatory elements. Northern blot analysis indicated that expression of the endogenous MDR1 gene was also elevated in Hep G2 clones with HBV pX expression. Decreased drug sensitivity towards adriamycin, vinblastine, and VP-16 was observed in Hep G2 clones with HBV pX expression.

CONCLUSIONS

HBV pX can transactivate the MDR1 gene. Drug sensitivity was altered in Hep G2 cells with HBV pX expression.