[The application of setting tube voltage and iodine delivery rate in weight-grouped for reducing the radiation and contrast medium dose in coronary CT angiography].

Objective: To evaluate the application value of reducing tube voltage and iodine delivery rate according to body weight in coronary CT angiography (CCTA). Methods: A prospective randomized controlled study. A total of 297 subjects, 172 males and 125 females, aged [M (Q1, Q3)]60.0 (50.0, 68.0) years, who underwent CCTA examination in Peking University Third Hospital due to clinically suspected coronary heart disease from May to December 2022 were included. According to the odd or even visit dates, the subjects were randomly divided into test group (n=156) and control group (n=141). The subjects in both groups were divided into four sub-groups according to body weight: 50-59 group, 60-69 kg group, 70-79 kg group and 80-89 kg group, respectively. The CCTA images were reconstructed with hybrid iterative algorithm(KARL 3D) with levels of 6 and 8, respectively. 100 kVp and iodine flow rate 1.1, 1.3, 1.4 and 1.5 gI/s recommended by the domestic CCTA application guidelines were used in the control group, while the tube voltage and iodine flow rate were reduced in the test group based on the guidelines and body weight:70 kVp and 0.8 g I/s in 50~59 kg group, 80 kVp and 1.0 gI/s in 60~69 kg group, 80 kVp and 1.1 gI/s in70~79 kg group, and 100 kVp and 1.5 gI/s in 80~89 kg group, respectively. The CT values and standard deviation (SD) of aortic root, proximal left anterior descending branch (LAD) and distal right coronary artery (RCA) luminal CCTA, the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of coronary artery CT images, subjective coronary scores and effective radiation dose (ED) were compared between the both groups. One-way ANOVA or Wilcoxon test was used to analyze the differences of above indicators between the groups to evaluate the application value of low voltage and low iodine flow rate based on weight in coronary CCTA. Results: CT values of aortic root, LAD proximal CT values and SD values of aortic root [411.4 (377.2, 439.8) HU, (366.3±42.9) HU, 26.5±2.3] in the test group were all higher than those in the control group [379.00 (335.2, 415.9) HU, (355.0±46.9) HU and 24.8±2.3]. The differences were statistically significant (all P<0.05), and the other parameters were not statistically significant (all P>0.05). The total subjective image quality score in test group were superior to those in the control group (all P<0.05). The total ED and contrast agent dosage [2.07 (1.52, 3.28) mSv and (38.28±9.68) ml] in CCTA examination in the test group were lower than those in the control group [3.30(2.32, 4.44) mSv and (45.31±5.63) ml], and the differences were statistically significant (all P<0.05). The dosage of ED and contrast agent in the test group was decreased by 37.3% and 15.5%, respectively. Conclusion: Combined with KARL 3D,it is feasible to reduce contrast medium and ED by setting the tube voltage and iodine flow rate of CCTA according to the weight of the subject, which can further reduce the radiation dose and contrast agent dosage of CCTA.

[Correlations between plaque characteristics and cerebral blood flow in patients with moderate to severe carotid stenosis using magnetic resonance vessel wall imaging].

OBJECTIVE: To investigate the correlations between carotid plaque characteristics and cerebral blood flow (CBF) in patients with unilateral moderate to severe carotid stenosis using high-resolution magnetic resonance imaging (HR-MRI) and 3D pseudo-continuous arterial spin labeling (3D pcASL). METHODS: A total of 43 patients with unilateral moderate to severe carotid stenosis were recruited. The degree of carotid stenosis, maximum wall thickness (Max WT) and normalized wall index (NWI) were measured using HR-MRI. The plaque characteristics were analyzed. Presence or absence of plaque components including intraplaque hemorrhage (IPH), lipid-rich necrotic nucleus (LRNC), calcification and ulcer were identified, and the grades of calcification and LRNC were recorded. CBF values within the region of interest representing the bilateral middle cerebral artery distribution were acquired using 3D pcASL. Paired sample t test was used to compare the differences of CBF values between the index side and the contralateral side. Spearman correlation analysis was conducted to evaluate the correlations of CBF values with the degree of carotid stenosis, Max WT and NWI. The differences of CBF values between the patients with or without IPH and ulcer were compared using Mann-Whitney U test. Different levels of calcification and LRNC were compared by Kruskal-Wallis test, respectively. RESULTS: The ave-rage degree of carotid stenosis at the index side was 77.30%±11.79%. The mean CBF value of the index side was (46.77±11.65) mL/(100 g·min), and that of the contralateral side was (49.92±9.95) mL/(100 g·min), and the difference was statistically significant (t=-2.474, P=0.017). The mean Max WT and NWI of the carotid plaques at the index side was (6.40±1.87) mm and 62.91%±8.87%, respectively. There were no significant correlations of CBF values with the degrees of stenosis, Max WT and NMI (P>0.05). Plaque composition analysis showed that the CBF values of the index side were different when there was calcification or not and the degrees of calcification were different (P=0.030), but there were no differences between the CBF values on the index sides with or without IPH, ulcer and LRNC. CONCLUSION: In patients with unilateral moderate to severe carotid stenosis, calcification might affect CBF perfusion. When there is no calcification, the plaque components need attention.

[Cortical thickness and cognitive impairment in patients with amyotrophic lateral sclerosis].

OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with high morbidity and mortality. There are about 5%-15% of ALS patients combining with frontotemporal lobe degeneration (FTLD) at the same time and 50% of patients combing with cognitive function changes. The analysis of cortical thickness based on MRI is an important imaging method to evaluate brain structure. The aim of the study was to explore the changes of brain structure in ALS patients by cortical thickness analysis, and to explore the correlation between the brain structure and cognitive function. METHODS: In the study, 18 ALS patients treated in Department of Neurology, Peking University Third Hospital and 18 normal controls (age, gender and education level matched) were included. 3D magnetization prepared rapid gradient echo imaging (MPRAGE) sequence MRI was performed and the cortical thickness was analyzed. At the same time, all the ALS patients took neuropsychology assessments, including: mini-mental state examination (MMSE), verbal fluency test (VFT), Stroop color word test (SCWT), prospective memory (PM), emotional picture perception and recognition, and faux pas story test. RESULTS: After cognitive assessment, two ALS patients had cognitive impairment. One was in accordance with ALS-frontotemporal dementia (FTD) diagnosis and the other one was in accordance with ALS cognitive impairment (ALSci) diagnosis. In all the 18 ALS patients and 18 normal controls, the cortical thickness of the left medial orbitofrontal lobe and the medial temporal lobe were significantly reduced (P < 0.05) in ALS group by the vertex-wise comparison. Cortical thickness of the left entorhinal cortex, the left inferior temporal gyrus, the left medial orbitofrontal lobe and the left insular lobe was significantly reduced (P < 0.05) by the region-wise comparison. However, when only concluded the 16 ALS non-cognitive impairment patients, there was no significant difference between the two groups (P>0.05). There were correlations between the scores of prospective memory, emotional picture perception and recognition, faux pas story test and the cortical thickness of their corresponding regions (P < 0.05). CONCLUSION: The cortical thickness of ALS patients are correlated with neuropsychological scores which may reflect the changes of cortical structure corresponding to the cognitive assessment, and may provide help for the early diagnosis of cognitive changes in ALS patients.

[Pay attention to the imaging research in marathon-related musculoskeletal injuries].

Marathon-related musculoskeletal injuries are very common. The imaging research of musculoskeletal injuries may provide scientific support for the health protection of marathon athletes. Unfortunately, imaging studies on musculoskeletal system injury are relatively lacking, large sample studies are almost blank, and neither imaging methods nor study populations are comprehensive enough. The imaging study of marathon-related musculoskeletal injuries remains to be further studied. As a country with a large number of marathon participants, China should strengthen relevant imaging studies to provide more health protection for marathon enthusiasts and professional athletes.

Whole-lesion histogram analysis of mono-exponential and bi-exponential diffusion-weighted imaging in differentiating lung cancer from benign pulmonary lesions using 3 T MRI.

AIM: To investigate whether whole-lesion histogram analysis of apparent diffusion coefficient (ADC) values derived from mono-exponential and bi-exponential diffusion-weighted imaging (DWI) can differentiate lung cancer from benign pulmonary lesions. MATERIALS AND METHODS: Thirty-two patients with lung cancer and 17 patients with benign pulmonary lesions were included retrospectively. All patients underwent DWI before surgery or biopsy. ADC histogram parameters, including mean, percentile values (10th and 90th), kurtosis, and skewness, were calculated independently by two radiologists. The histogram parameters were compared between patients with lung cancer and benign lesions. Receiver operating characteristic curves were constructed to evaluate the diagnostic performance. RESULTS: The ADCMean, ADC10th, DMean, D10th were significantly lower in lung cancer (1.187 ± 0.144 × 10-3; 0.440 ± 0.062 × 10-3; 1.068 ± 0.108 × 10-3; and 0.422 ± 0.049 × 10-3 mm/s) compared to benign lesions (1.418 ± 0.274 × 10-3; 0.555 ± 0.113 × 10-3; 1.216 ± 0.149 × 10-3; and 0.490 ± 0.044 × 10-3 mm/s; p<0.05). The ADCSkewness and DSkewness were significantly different between lung cancer (2.35 ± 0.72; 2.58 ± 1.14) and benign lesions (1.85 ± 0.54; 1.59 ± 1.47; p<0.05). D10th was robust in differentiating lung cancer from benign lesions. Using 0.453 × 10-3 mm/s as the optimal threshold, the sensitivity, specificity, and accuracy of D10th were 78.12%, 82.35%, and 79.6%, respectively. CONCLUSION: Whole-lesion histogram analysis of ADC values derived by mono-exponential and bi-exponential DWI using 3 T magnetic resonance imaging helps distinguish lung cancer from benign pulmonary lesions.

Comparative analysis and differentiation between SAPHO syndrome and spondyloarthropathies using whole-spine MRI.

AIM: To determine the imaging characteristics of SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome and seronegative spondyloarthropathies (SpAs) on whole-spine magnetic resonance imaging (WS-MRI) and evaluate the role of WS-MRI in the diagnosis and differentiation of the two diseases. MATERIALS AND METHODS: Twenty-eight patients with SAPHO and 44 with SpAs were included. All patients were symptomatic and clinically diagnosed with SAPHO or SpAs, and all underwent WS-MRI for comparison of imaging characteristics. RESULTS: The mean age of the SAPHO patients was 48.7 ± 12.7 years, while that of the SpA patients was 34.7 ± 12.3 years (p<0.001). WS-MRI showed that the frequency of cervical, thoracic, and lumbar spine involvement was 53.6% versus 52.3%, 75% versus 88.6%, and 60.7% versus 63.6%, respectively (p=0.70, 0.13, and 0.80). The frequency of sacroiliac joint involvement was 7.1% and 100% (p<0.001). Continuous spinal involvement accounted for 50% versus 43.2%, 60.7% versus 84.1%, and 39.3% versus 40.9% in the cervical, thoracic, and lumbar vertebrae, respectively (p=0.03). WS-MRI showed that bone marrow oedema of spinal anterior corner was observed in 50% versus 75% (p=0.03). Vertebral body and posterior attachment involvement accounted for 85.7% versus 93.2% and 14.3% versus 34.1% (p=0.3, 0.06). The frequency of bone erosion in mobile spine was 75% and 36.4%, respectively (p=0.02). The frequency of intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue swelling was 42.9% versus 18.2%, 53.6% versus 22.7%, 85.7% versus 42.2%, and 50% versus 11.4% (p=0.02, 0.00). CONCLUSIONS: Factors differentiating the two groups at WS-MRI were bone marrow oedema of the spinal anterior corner, bone erosion, and swelling of the intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue.

[CT spectral curve in differentiating spinal tumor metastasis and infections].

OBJECTIVE: To evaluate the value of CT spectral curve in differentiating spinal tumor metastasis (STM) from spinal infections (SI). METHODS: In the study, 29 STM and 18 SI patients proved pathologically and clinically were examined by dual energy spectral CT (DESCT). The monochromatic images and CT spectral curves were generated automatically by GSI Viewer software. The attenuation values at different energy levels (40-140 keV, every 10 keV), the attenuation values of the lesions on the conventional polychromatic CT images and the gradients of the curve were calculated and compared between STM and SI. RESULTS: The median age of STM and SI (58 years vs. 64 years) were not significantly different (U=171, P=0.4). The attenuation values of STM at 40-100 keV were 281.79 (143.67, 446.19) HU, 199.68 (100.04, 321.49) HU, 151.54 (81.47, 243.49) HU, (122.64±27.72) HU, (99.90±23.88) HU, (85.82±21.61) HU, and (75.94±20.27) HU, respectively, which were significantly higher than SI: 185.29 (164.19, 277.03) HU, 138.44 (124.98, 238.56) HU, 105.46 (92.94, 169.53) HU, (93.77±15.55) HU, (79.15±12.84) HU, (68.99±11.75) HU, and (62.22±11.71) HU (all P < 0.05). The attenuation values at 110-140 keV and the attenuation value on the conventional CT images were not significantly different between STM and SI. The gradient of CT spectral curve of STM was 2.43±0.58, which was higher than the value of 1.50±0.40 for SI (P < 0.001). Using 1.72 and 248.80 HU as the threshold value for CT spectral curve slope and the attenuation value at 40 keV, could obtain the area under receiver operating characteristic (ROC) curve of 0.905 and 0.892, sensitivity of 88.0% and 80.0%, and specificity of 76.9% and 92.3%. CONCLUSION: CT spectral curve provides valuable semi-quantitative information for the differential diagnosis of STM and SI, which can be used as a supplement to traditional CT imaging.

[Clinical value of artifact identification in ankle dual-energy CT for gout diagnosis].

Objective: To investigate the clinical value of artifact identification in ankle dual-energy CT for gout diagnosis. Methods: A total of 58 patients with gout, who were definitely diagnosed in Peking University Third Hospital from December 2018 to May 2019, were included in the case group, which were composed of 57 males and 1 female. And 37 individuals without gout were regarded as control group, which were composed of 36 males and 1 female. Dual-energy CT was performed for one foot, and the affected side or the more serious side was chosen in the case group. The dual-energy data were used in gout-recognition software to highlight the monosodium urate (MSU) with green-colored. And to compare the difference in MSU relevance ratio on the images of toenail, submillimeter spots, skins, movements and vascular calcification between two groups. Results: In the case group, 55 patients were revealed with MSU green-colored toenails (relevance ratio 94.8%), while 22 cases in the control groups (relevance ratio 59.5%). There was significantly statistical difference on the mean toenails numbers and the MSU distribution scores in the two groups (all P<0.01). In the case group, 47 patients were revealed with green-colored submillimeter spots (relevance ratio 81.0%),while 5 cases in the control group (relevance ratio 13.5%). The relevance ratio of submillimeter spots on tendon and ligament in the case group and control group were 75.9% (44/58) and 13.5%(5/37). There was also significantly statistical difference in the two groups on submillimeter spots (all P<0.01). And there was no significantly statistical difference in the two groups on MSU green-colored skins, movements and vascular calcification. Conclusion: There is great value for gout clinical diagnosis when green-colored MSU is detected on toenails and submillimeter spots, which should not be judged as artifact simply.

[Study on the deposition of monosodium urate in patients with first-episode of acute gouty arthritis by dual energy CT].

Objectives: To investigate the characteristics of monosodium urate (MSU) deposition in patients with the first-episode of acute gouty arthritis (Gout) by using dual energy CT (DECT) imaging technique. Methods: A total of 70 first-episode patients with acute Gout diagnosed in Peking University Third Hospital in 2019 were collected as the case group, including 69 males and 1 female, aged 17-65 (39±14) years. During the same period, a total of 15 male patients aged 19-56 (33±12) years were collected as the control group. They were admitted to the hospital due to sports injuries and were excluded from gout. The DECT data of the first-affected or the most painful joints of gout in the case group and the surgical ankle joints in the control group were retrospectively analyzed. The crystal morphology, volume and deposition location of MSU in the measured joints were evaluated and recorded, and the degree of MSU deposition in the joints of the first-episode patients with Gout and its coincidence with clinical symptoms were summarized. The χ(2) test, and Kruskal-walls were used for statistical analysis. Results: The detection rate of MSU by DECT in the case group was 97.1% (68/70), and 0 in the control group. The first-affected joints of Gout included 52 cases of ankles (74.3%), 13 cases of knees (18.6%), and 5 cases of wrists (7.1%). The three joints were mainly deposited with scattered submillimeter MCU. There was no significant difference in MSU morphology and volume between the three joints. The locations with the most MCU deposits among the three joints were 78.8% (41/52) of the posterior calf tendons (including Achilles tendon), 76.9% (10/15) of the knee articular cartilages, and 60.0% (3/5) of the palmaris tendons, while the distribution of the first metatarsophalangeal joint was less than 13.5% (7/52). The number of MSU deposited joints detected by DECT was 37 cases more than that of symptomatic joints, accounting for 52.8%. Conclusions: DECT is highly sensitive in detecting MCU in the first-episode of acute Gout, which helps to improve the early diagnosis rate of gout.

[Cerebral blood flow measurements in patients with comorbid hypertension and depression using 3D arterial spin labeling].

OBJECTIVE: To evaluate cerebral blood flow (CBF) in patients with comorbid hypertension in depression using 3D pseudocontinuous arterial spin labeling (3D pcASL) and to compare the differences of CBF values in depression, hypertension, and comorbid hypertension between depression and healthy control groups. To investigate the correlation between CBF values and degrees of depression. METHODS: Sixteen patients with depression (depression group, 3 males and 13 females, age range of 42-72 years old), sixteen patients with hypertension (hypertension group, 3 males and 13 females, age range of 41-68 years old), sixteen patients with comorbid hypertension in depression (comorbidity group, 3 males and 13 females, age range of 45-74 years old), and sixteen healthy controls (control group, 3 males and 13 females, age range of 43-68 years old) were recruited. 3D pcASL sequence was performed by GE 3.0T magnetic resonance scanner and CBF map was generated automatically. Statistical parametric mapping (SPM8) was performed to preprocess the CBF map, which was spatially normalized and smoothed. Comparison of the CBF values among the four groups was conducted by ANOVA. Correlation between the average CBF values in areas of decreased CBF and Hamilton depression scale (HAMD-17) was investigated. RESULTS: The patients with comorbid hypertension in depression demonstrated lower CBF in bilateral superior frontal gyri, middle frontal gyri, inferior frontal gyri, right superior parietal gyrus, right inferior parietal gyrus, right supramarginal gyrus, left caudate nucleus and left insula lobe in comparison with the controls. Compared with control group, CBF values decreased in bilateral frontal lobes, but did not reach statistical significance. There were no significant differences of CBF values between the patients with hypertension and control subjects. Compared with depression, the patients with comorbid hypertension in depression showed lower CBF values in bilateral frontal lobes and right supramarginal gyrus. Compared with hypertension, lower CBF values in left middle frontal gyrus in the patients with comorbid hypertension in depression were shown. Correlation analysis indicated that no correlation between CBF values and scores of HAMD-17 was shown. CONCLUSION: Although there were no significant decreases of CBF values in patients with depression and hypertension, regional hypoperfusions were observed in patients with comorbid hypertension in depression. Hypertension might play a synergistic action on cerebral hypoperfusion in patients with comorbid hypertension in depression.

[CT-guidance interstitial Iodine-125 seed brachytherapy as a salvage therapy for recurrent head and neck carcinoma].

Objective: To investigate the efficacy of CT-guidance interstitial Iodine-125 seed brachytherapy as a salvage therapy for recurrent head and neck carcinoma. Methods: A total of 122 patients who had been treated for recurrent head and neck carcinoma with CT-guided Iodine-125 seed permanent implantation were conducted a retrospective analysis at Peking University Third Hospital from February 2003 to December 2015. The study included 78 male and 44 female patients. Of the 122 patients, 76 had undergone radical surgery, 106 had received EBRT. Among the patients who underwent EBRT, the total dose delivered to PTV ranged from 30 to 140 Gy (median, 68.4 Gy). The actuarial median number of the implanted Iodine-125 seeds was 38 (range, 5-158). The specific activity of Iodine-125 seeds ranged from 14.8 to 28.9 MBq/seed (median, 22.2 MBq). The evaluation of post plan showed the actuarial D90 ranged from 46 to 282 Gy (median, 121 Gy). The overall local control and survival times were determined by using the Kaplan-Meier method from SPSS 13.0.Univariate analysis was performed on the local control rate and overall survival rate. Results: Tumor responses rate was 75.4%. The median local control time was 10.0 months (95% CI 9.8-24.2 months), and the 1-, 2-, 3-, and 5-year local control were 41.9%, 21.2%, 3.7%, and 3.7%, respectively. Univariate analysis showed that the local control in D90≥120 Gy group had an increasing tendency, but no statistical difference were found. The effect of local control in the squamous cell carcinoma group was slightly worse than that in the non-squamous cell carcinoma group (P=0.032). Multi-factor analysis showed that the effect of local control in the squamous cell carcinoma group was slightly poor (P=0.03). The median survival time was 14 months (95% CI 14.4-35.8 months), and the 1-, 2-, 3- and 5-year survival rate were 51.5%, 34.2%, 19.4%, and 19.4%, respectively. The three factors, such as the tumor responses, KPS status before the seed implantation, and the D90 after the seed implantation, had a tendency to improve the total survival, but there was still no statistical differences. Multivariate analysis showed no clear influence factors. Conclusions: Interstitial permanent Iodine-125 seed implantation is an effective salvage re-irradiation modality for recurrent head and neck carcinoma after previous surgery and/or EBRT. CT image-guided method could yield the reliable seeds configuration and accurate dose distribution.

Combination of cells-based therapy with apelin-13 and hyperbaric oxygen efficiently promote neovascularization in ischemic animal model.

OBJECTIVE: Critical lower-limb ischemia (CLLI) is characterized by high morbidity and mortality. The aim of this study was to explore the effectiveness of the combination of cell therapy with apelin-13 and hyperbaric oxygen in CLLI animal model. MATERIALS AND METHODS: The experimental ischemic rats were divided into five groups, including negative control, bone marrow derived mononuclear cells (BM-MNCs), apelin-13, hyperbaric oxygen treatment (HBOT) and apelin-13 with HBOT group. Each group was composed of 10 rats. Endothelial progenitor cells (EPCs) derived from bone marrow were transplanted into the ischemia rat model. After 3 weeks of transplantation, the formation of new vessels was evaluated by examining cluster of differentiation (CD)31, CD34 and vascular endothelial growth factor receptor 2 (VEGFR-2) expressions as well as a direct vision of vessels by hematoxylin and eosin (HE) staining and immunohistochemistry. RESULTS: Compared with the negative control group, both angiogenic factors expressions and the number of new vessels increased notably by the transplantation of BM-MNCs in the ischemic models. Apelin-13 or HBOT alone improved the efficacy within limit while the combination of the three elements remarkably promoted the neovascularization in ischemic limbs. CONCLUSIONS: BM-MNC induced angiogenesis in the ischemic limbs and was considered an effective resource for cell therapy. The preliminary data of this study showed that the combination of cell therapy with apelin-13 and HBOT improved the efficacy of angiogenesis.

Combination pharmacological cardioversion of permanent atrial fibrillation in post-prosthetic mitral valve replacement outpatients: a novel approach for the treatment of atrial fibrillation.

This study explored the efficacy and safety of combination pharmacological cardioversion of permanent atrial fibrillation in outpatients following prosthetic mitral valve replacement. The study group comprised 99 outpatients who were randomly divided into two groups. In group 1 (n = 50), only ventricular heart rate was controlled. In group 2 (n = 49), combination pharmacological cardioversion therapy with low-dose oral amiodarone (2 mg/kg), captopril (0.25 mg/kg) and simvastatin (0.3 mg/kg) was administered daily. During 12 months of serial pharmacological treatment, the cardioversion rate was 6% for group 1 and 39% for group 2; the likelihood of cardioversion differed significantly between the two groups. In group 2, one patient developed severe pruritus that necessitated withdrawal from the study and six patients ceased captopril treatment after contracting a persistent cough. In summary, combination pharmacological cardioversion was found to be effective and safe in outpatients who had undergone prosthetic mitral valve replacement.

Imaging Appearances and Pathologic Characteristics of Spinal Epidural Meningioma.

BACKGROUND AND PURPOSE: Spinal epidural meningioma is an uncommon tumor. This study aimed to analyze the imaging and pathologic characteristics of this rare tumor. MATERIALS AND METHODS: Fourteen confirmed cases of epidural meningioma were retrospectively reviewed, and imaging characteristics and pathologic findings were analyzed to identify the typical features. RESULTS: The mean age of the patients (4 men, 10 women) was 44.9 years. Twelve tumors were in the cervical spinal canal, and 2, in the thoracic spinal canal. There were 9 en plaque meningiomas, 4 dumbbell-shaped meningiomas, and 1 fusiform/ovoid meningioma. The epidural meningiomas extended over 2-5 spinal segments (mean, 3.2 spinal segments). A soft epidural mass was seen in 12/14 (86%) patients. Dural calcification was seen in 8/14 (57%) tumors. Tumor caused intervertebral foramen enlargement in 10/14 (71%) patients and adhered to the nerve roots in 11/14 (79%) patients. Intradural invasion was seen in 8/14 (57%) patients. The dural tail sign was present in 13/14 (93%) tumors on contrast-enhanced T1WI. Regarding pathologic type, 10 of 14 (71%) were psammomatous, 2 of 14 (14%) were meningothelial, 1 of 14 (7%) was angiomatous, and 1 of 14 (7%) was transitional. During follow-up (mean follow-up, 73.4 months; range, 4-192 months), 7 patients had recurrence. Recurrences were between 4 and 192 months after the operation. CONCLUSIONS: Epidural meningioma has 3 different growth patterns. Dural thickening, calcification, invasion, and epidural mass formation are characteristic features of epidural meningioma. Regular follow-up imaging is required to detect recurrence.

Distribution of sorbed phenanthrene and pyrene in different humic fractions of soils and importance of humin.

Contributions of fulvic-humic acids (FA/HA) and humin (HM) to sorption of phenanthrene (PHE) and pyrene (PYR) in a soil were differentiated using a humic separation procedure after multi-concentration sorption experiments. It was found that the amount of solutes in FA/HA did not change significantly after 48 h, while that in HM increased continuously and slowly up to the end of the experimental period (720 h), indicating that HM was the main region for slow sorption. Based on the fitting results using Freundlich equation, it was found that nonlinearity of both solutes was greater in HM than in FA/HA, consistent with the sorption characteristics of individually extracted HA and HM in a separate experiment. The observed nonlinearity of the solute distribution was confirmed by using three other soil samples with organic carbon contents ranging from 0.7 to 7.9%. Distribution dynamics of PHE and PYR among various fractions were also discussed.

The crystal structure of the DNase domain of colicin E7 in complex with its inhibitor Im7 protein.

BACKGROUND: Colicin E7 (ColE7) is one of the bacterial toxins classified as a DNase-type E-group colicin. The cytotoxic activity of a colicin in a colicin-producing cell can be counteracted by binding of the colicin to a highly specific immunity protein. This biological event is a good model system for the investigation of protein recognition. RESULTS: The crystal structure of a one-to-one complex between the DNase domain of colicin E7 and its cognate immunity protein Im7 has been determined at 2.3 A resolution. Im7 in the complex is a varied four-helix bundle that is identical to the structure previously determined for uncomplexed Im7. The structure of the DNase domain of ColE7 displays a novel alpha/beta fold and contains a Zn2+ ion bound to three histidine residues and one water molecule in a distorted tetrahedron geometry. Im7 has a V-shaped structure, extending two arms to clamp the DNase domain of ColE7. One arm (alpha1(*)-loop12-alpha2(*); where * represents helices in Im7) is located in the region that displays the greatest sequence variation among members of the immunity proteins in the same subfamily. This arm mainly uses acidic sidechains to interact with the basic sidechains in the DNase domain of ColE7. The other arm (loop 23-alpha3(*)-loop 34) is more conserved and it interacts not only with the sidechain but also with the mainchain atoms of the DNase domain of ColE7. CONCLUSIONS: The protein interfaces between the DNase domain of ColE7 and Im7 are charge-complementary and charge interactions contribute significantly to the tight and specific binding between the two proteins. The more variable arm in Im7 dominates the binding specificity of the immunity protein to its cognate colicin. Biological and structural data suggest that the DNase active site for ColE7 is probably near the metal-binding site.

Structural analysis of the transcriptional activation region on Fis: crystal structures of six Fis mutants with different activation properties.

The Fis protein regulates gene expression in Escherichia coli by activating or repressing transcription of a variety of genes. Fis can activate transcription when bound to DNA upstream of the RNA-polymerase-binding site, such as in the rrnB P1 promoter, or when bound to a site overlapping the -35 RNA polymerase binding site, such as in the proP P2 promoter. It has been suggested that transcriptional activation in both promoters results from interactions between specific amino acids within a turn connecting the B and C helices (the BC turn) in Fis and the C-terminal domain of the alpha-subunit of RNA polymerase (alphaCTD of RNAP). Here, crystal structures of six Fis BC turn mutants with different transcriptional activation properties, Q68A, R71Y, R71L, G72A, G72D and Q74A, were determined at 1.9 to 2.8 A resolution. Two of these mutants, R71Y and R71L, crystallized in unit cells which are different from that of wild-type Fis, and the structure of R71L offers the most complete Fis model to date in that the extended structure of the N-terminal region is revealed. The BC turn in all of these mutant structures remains in a nearly identical gamma gamma beta-turn conformation as present in wild-type Fis. Analyses of the molecular surfaces of the transactivation region of the mutants suggest that several residues in or near the BC turn, including Gln68, Arg71, Gly72 and Gln74, form a ridge that could contact the alphaCTD of RNAP on one side. The structures and biochemical properties of the mutants suggest that Arg71 is the most critical residue for contacting RNAP within this ridge and that the glycine at position 72 helps to stabilize the structure.

Structural basis of non-specific lipid binding in maize lipid-transfer protein complexes revealed by high-resolution X-ray crystallography.

Non-specific lipid-transfer proteins (nsLTPs) are involved in the movement of phospholipids, glycolipids, fatty acids, and steroids between membranes. Several structures of plant nsLTPs have been determined both by X-ray crystallography and nuclear magnetic resonance. However, the detailed structural basis of the non-specific binding of hydrophobic ligands by nsLTPs is still poorly understood. In order to gain a better understanding of the structural basis of the non-specific binding of hydrophobic ligands by nsLTPs and to investigate the plasticity of the fatty acid binding cavity in nsLTPs, seven high-resolution (between 1.3 A and 1.9 A) crystal structures have been determined. These depict the nsLTP from maize seedlings in complex with an array of fatty acids.A detailed comparison of the structures of maize nsLTP in complex with various ligands reveals a new binding mode in an nsLTP-oleate complex which has not been seen before. Furthermore, in the caprate complex, the ligand binds to the protein cavity in two orientations with equal occupancy. The volume of the hydrophobic cavity in the nsLTP from maize shows some variation depending on the size of the bound ligands. The structural plasticity of the ligand binding cavity and the predominant involvement of non-specific van der Waals interactions with the hydrophobic tail of the ligands provide a structural explanation for the non-specificity of maize nsLTP. The hydrophobic cavity accommodates various ligands from C10 to C18. The C18:1 ricinoleate with its hydroxyl group hydrogen bonding to Ala68 possibly mimics cutin monomer binding which is of biological importance. Some of the myristate binding sites in human serum albumin resemble the maize nsLTP, implying the importance of a helical bundle in accommodating the non-specific binding of fatty acids.

Conversion of a beta-strand to an alpha-helix induced by a single-site mutation observed in the crystal structure of Fis mutant Pro26Ala.

The conversion from an alpha-helix to a beta-strand has received extensive attention since this structural change may induce many amyloidogenic proteins to self-assemble into fibrils and cause fatal diseases. Here we report the conversion of a peptide segment from a beta-strand to an alpha-helix by a single-site mutation as observed in the crystal structure of Fis mutant Pro26Ala determined at 2.0 A resolution. Pro26 in Fis occurs at the point where a flexible extended beta-hairpin arm leaves the core structure. Thus it can be classified as a "hinge proline" located at the C-terminal end of the beta2-strand and the N-terminal cap of the A alpha-helix. The replacement of Pro26 to alanine extends the A alpha-helix for two additional turns in one of the dimeric subunits; therefore, the structure of the peptide from residues 22 to 26 is converted from a beta-strand to an alpha-helix. This result confirms the structural importance of the proline residue located at the hinge region and may explain the mutant's reduced ability to activate Hin-catalyzed DNA inversion. The peptide (residues 20 to 26) in the second monomer subunit presumably retains its beta-strand conformation in the crystal; therefore, this peptide shows a "chameleon-like" character since it can adopt either an alpha-helix or a beta-strand structure in different environments. The structure of Pro26Ala provides an additional example where not only the protein sequence, but also non-local interactions determine the secondary structure of proteins.

Continuous production of high degree casein hydrolysates by immobilized proteases in column reactor.

The enzymatic complete hydrolysis of casein was investigated by using immobilized endopeptidase and exopeptidase packed in the jacketed column reactors. The mass transfer efficiency of proteins was improved by using sliced shrimp chitin hull as enzyme support, which formed a network structure inside the column reactor that prevented the formation of protein precipitate and increased the line flow rate of protein solution. The specificity of the protease was of crucial importance for both the hydrolysis degree and the free amino acid content of the hydrolysates. Of the enzymes, tested, the immobilized A. oryzae protease was the most effective enzyme in breaking down the casein molecules and releasing the free amino acid from casein hydrolysates. The immobilized pancreatic and kidney exopeptidase could lead to a 20% increase of free amino acids. The free amino acid content of casein hydrolysates was 34.81% after processing and could reach to 64% if the column length was doubled, but 100% hydrolysis was impossible as the reverse reaction was also taking place. The casein hydrolysates was characterized by its high degree of hydrolysis and high content of free amino acids. It can be applied in infant formula, element diet, and as a protein ingredient for food industry.