A rapid method for directly determining tryptophan contents in foods and feedstuffs was described. l-5mg dry sample could be completely hydro-lyzed in a teflon tube containing 5N NaOH with 0.5% soluble starch under 145℃ for 4 hours in vacuum (760mmHg). The hydrolysate was then adjusted to neutral with 6N HCL in icebath and diluted by five times with 4M urea solution (pH = 11), and was measured at excitation wavelength 280nm and fluorescence wavelength 368nm. The sensitivity of the method was 5ng /10ml, and the recovery rate of 97-107% were obtained in the range of 1-5 ?g/10ml standard tryptophan. The value of a number of foods and feed-stuffs obtained were in agreement with the literatature values.

Objective To investigate the CT features of mesenteric lymph nodes in patients with active Crohn’s disease.Methods The CT findings in 54 patients with active Crohn's disease proved by histology were analyzed,and the anatomic distribution,size, number,shape and enhancement ratio (ER)of the mesenteric lymph node were assessed.Results Mesenteric lymphadenopathy in 38 patients (70.4%)was found with a total number of 242,83.5%(202/242)of whom were located at the mesenteric root and 16.5%(40/242) at mesenteric edge.The size of the lymph nodes at the mesenteric root was larger than that at the mesenteric edge (8.57 mm±2.26 mm versus 5.38 mm±0.1 9 mm,the mean maximum short diameter),and 73.6% (1 78/242 )of the lymph nodes were oval in shape.The lymph nodes showed significant enhancement after contrast injection with an ER of 0.53 ±0.09.Conclusion Active CD often leads to mesenteric lymphadenopathy,which is more obvious at the mesenteric root.

Objective To investigate the imaging characteristics of rabbit liver VX2 tumor with contrast-enhanced ultrasonography(CEUS) and multidetector spiral CT(MDCT), to explore the criterion of phase timing apllicable to the model.Methods CEUS and MDCT were acquired in thirty-three New Zealand rabbits with hepatic VX2 tumors.The initial time of hepatic arterial phase was verified as the time the hepatic artery beginning to enhance,the initial time of portal phase as the time the VX2 tumor reaching peak enhancement and the initial time of hepatic parenchymal phase as the time the hepatic parenchyma reaching peak enhancement.The enhancing characteristics were observed.The time-intensity curve of VX2 tumor and peripheral parenchyma in CEUS was analysed and compared with the time-desity curve of abdominal aorta, portal vein, hepatic parenchyma and tumor in MDCT.Results The initial time of heptic arterial phase,portal phase and parenchymal phase in CEUS and MDCT was (6.82±1.36)s and (9.43±2.23)s,(11.64±2.03)s and (13.77±2.01)s,(20.24±4.17)s and (22.71± 4.58)s,respectively.The initial time of each phase in CEUS was earlier than that in MDCT (P<0.01).The contrast enhancing characteristics in CEUS and MDCT were consistent as fast wash-in and fast wash-out.Conclusions The status of hemodynamic perfusion in rabbit hepatic VX2 tumor could be well displayed by CEUS and the phase timing criterion concluded in this experimental study could offer fundmental theory basis for relevant imaging evaluation.

ObjectiveTo measure the perfusion parameters of liver fibrosis of dog model with 64-slice spiral CT,and compare with positive control to reflect the degree of liver fibrosis,and analyze the correlation with VEGF values.Methods Liver fibrosis was induced in dogs by intraperitoneal injection of CC14 and high fat diet.CT perfusion scan and liver biopsies were performed.The perfusion parameters were measured according to the liver fibrosis models,and the correlation with VEGF values was analyzed.ResultsThe animals in experimental group were successfully induced different degree of liver fibrosis.In normal group,the hepatic artery perfusion,portal vein perfusion and total hepatic blood flow were (28.25 ±2.19)ml/(min · 100 g),(53.53 ± 10.71)ml/(min · 100 g) and (81.78 ± 18.56) ml/(min · 100 g).The PVP and TLP values of the liver fibrosis models of 0 - 4 stages declined gradually,and it had statistical significance,while the HAP values increased.The PVP and TLP values were positive correlated with fibrosis stage.The VEGF values of the pathological models of 0 - 4 stages ascended significantly.Conclusions The dog liver fibrosis models that are similar to human hepatic fibrosis have been successfully induced by low dose CC14 and high fat diet.CT perfusion can be used to monitor the tendency of the hemodynamic in different degree of fibrosis.VEGF may play an important role during liver fibrogenesis.

To explore the value of the third generation dual-source computed tomography (CT) convolution kernel in display of pulmonary ground-glass nodule (GGN) in transverse image reconstruction.
 Methods: A total of 52 lung adenocarcinoma patients with lung CT data were selected from February 2018 to January 2019 for this study. The pulmonary CT data were reconstructed by convolutional nucleus B157, Br54, and Br49. The signal-to-noise ratio (SNR), the contrast-to-noise ratio (CNR), and the standard deviation (SD) of the image at the GGN were used as the objective evaluation standard of image quality. Subjective image quality was scored by 2 radiologists from 3 aspects (overall image quality, noise, and lesion outline).
 Results: Objective image quality evaluation, SNR and CNR of reconstructed convolution kernel Br49 (SNR: 11.36±5.39, CNR: 7.19±4.29), Br54 (SNR: 8.30±3.35, CNR: 5.09±2.86) are greater than those of Bl57 (SNR: 4.18±2.10, CNR: 3.25±1.78; all P<0.01). SD of reconstructed convolution kernel Br49 (61.80±20.17) and Br54 (80.45±20.31) is smaller than that of Bl57 (137.92±31.11, both P<0.01). In the subjective image quality evaluation, the overall image quality score 5.0(4.5, 5.0) of Br54 was higher than that of all other images [Br49: 3.0(3.0, 4.0), Bl57: 3.0(3.0, 3.5); both P<0.05]. The Br54 image showed that the lesion contour ability score 5.0(4.0, 5.0) was higher than all other images [Br49: 4.0(4.0, 5.0), Bl57: 3.0(3.0, 3.0); both P<0.05]; Br49 image noise score 3.0(3.0, 3.0) is the lowest one [Br54 4.0(4.0, 4.0), Bl57 5.0(5.0, 5.0); both P<0.05].
 Conclusion: The reasonable selection of CT convolution kernel plays an important role in the subjective and objective image quality of GGN. It is suggested that Br54 should be used as the reconstruction of convolutional kernel in pulmonary ground glass nodules, which is helpful for doctors to find and diagnose GGN.
Algorithms ; Humans ; Radiation Dosage ; Radiographic Image Interpretation, Computer-Assisted ; Signal-To-Noise Ratio ; Tomography, X-Ray Computed

To explore the feasibility and clinical value of CT-based arterial enhancement fraction (AEF) for evaluating liver function in liver cirrhosis patients.
 Methods: Fifty-two patients with liver cirrhosis (Child-Pugh A, B, and C group included 13, 20, and 19 patients, respectively) and 17 patients without liver diseases as control were prospectively enrolled, respectively. All individuals underwent three-phase hepatic CT, and the color mapping of AEF were obtained in CT kinetics software, as well as the corresponding parameters, i.e., hepatic AEF (HAEF) and the ratio of HAEF to spleen AEF (H/S). The AEF parameters were compared among different groups, and the area under the receiver operating characteristic curve (AUROC) was calculated. The Spearman correlation analysis was performed between the AEF parameters and model for end-stage liver disease (MELD) score in liver cirrhosis patients.
 Results: The interobserver agreement of HAEF and H/S were perfect, and the intraclass correlation coefficient (ICC) were 0.918 (95% CI 0.871 to 0.949), 0.946 (95% CI 0.915 to 0.966), respectively. The HAEF and H/S among those groups were significant different (both P<0.001), and they elevated with the increase of Child-Pugh classification in liver cirrhosis patients (all P<0.05, except the H/S between Child-Pugh A and B). In all patients with liver cirrhosis, the AUROC of HAEF and H/S were 0.933 and 0.821 for Child-Pugh A, and were 0.925 and 0.915 for Child-Pugh C, respectively. The HAEF and H/S of patients with liver cirrhosis were significantly correlated with the MELD score (HAEF: r=0.752, P<0.001; H/S: r=0.676, P<0.001).
 Conclusion: CT-based AEF parameters including HAEF and H/S are closely associated with the severity and prognosis of patients with liver cirrhosis, which have the potential to estimate the liver function in liver cirrhosis patients quantitatively and effectively.
Humans ; Liver Cirrhosis ; diagnostic imaging ; Liver Function Tests ; Tomography, X-Ray Computed

BACKGROUND: Airway stents are used to treat central airway stenosis or tracheal fistula caused by a variety of malignant and benign tracheal diseases as well as iatrogenic procedures. Airway stent placement has a satisfying effect in instantly relieving of symptoms, but the long-term survival of patients still depends on the individualized treatment of the primary diseases. Therefore, exploring the prognostic risk factors of patients who received airway stent placement can be beneficial to the optimization of the placement procedure and also the improvement of individualized clinical management of patients. METHODS: Data of a total of 66 patients who underwent airway stent placement at the First Affiliated Hospital of Zhejiang University from January 2014 to June 2017 were retrospectively collected. Prognostic effects of the clinical characteristics as age, gender, Charlson comorbidity index (CCI) and procedure duration were analyzed. RESULTS: Age and gender had no significant effect on the outcomes of the patients, while higher CCI (P=0.045) and procedure duration over 60 min (P=0.037) were both independent risk factors of poor prognosis. A prognostic nomogram was then constructed, of which the area under the curve of the receiver operating characteristic (ROC) curve and the concordance index (C-index) was 0.71 and 0.69, respectively. CONCLUSIONS For patients receiving airway stent placement, the baseline CCI and the procedure duration had prognostic significance in clinical practice.