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[Interleukin 33 inhibits lipopolysaccharide-induced high permeability of cardiac microvascular endothelial cells]. ZHONGHUA NEI KE ZA ZHI 2022; 61:559-564. [PMID: 35488608 DOI: 10.3760/cma.j.cn112138-20210625-00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Objective: To investigate the effect of interleukin-33 (IL-33) on lipopolysaccharide (LPS)-induced permeability of rat cardiac microvascular endothelial cells (RCMECs). Methods: RCMECs were cultured in vitro to be divided into control group, LPS group, IL-33 group and LPS+IL-33 group. The effect of IL-33 on the proliferation of RCMECs was detected by cell counting reagent (CCK8). Fluorescein isothiocyanate (FITC)-dextran assay was used to evaluate the permeability of RCMECs. The expression of vascular endothelial calmodulin, ras homologous gene family (Rho) member A (RhoA) and phosphorylated Rho-associated coiled-coil-containing protein kinase (p-ROCK2) proteins were tested by western blot. High-throughput sequencing and gene ontology (GO) were performed for gene expression in LPS and LPS+IL-33 groups. Results: No significant effect of IL-33 at 10-50 ng/ml on the proliferation of RCMECs was observed (P>0.05). Compared with the control group, the permeability of RCMECs (permeability coefficient ratio 1.404±0.029 vs. 1.000±0.200, P<0.05) was significantly increased in LPS group and the expression of vascular endothelial calmodulin (relative gray value 0.429 5±0.012 9 vs. 0.594 9±0.014 2, P<0.05) was down-regulated, while the permeability of monolayers (permeability coefficient ratio, 0.948±0.013, P<0.01) was decreased in LPS+IL-33 group and the expression of vascular endothelial calmodulin (relative grayscale value 0.549 1±0.012 0, P<0.005) was up-regulated compared with the LPS group. High-throughput sequencing data revealed that the differential genes downregulated in the LPS and LPS+IL-33 groups were associated with cytoskeleton and Rho signaling pathway. Compared with the control group, RhoA (relative gray value 0.211 4±0.009 9 vs. 0.135 0±0.007 6, P<0.000 1) and p-ROCK (relative gray value 0.656 3±0.013 2 vs. 0.503 6±0.036 2, P<0.000 1) protein expression was upregulated in the LPS group. When compared with LPS group, RhoA (relative gray value 0.157 7±0.010 7, P=0.000 2), p-ROCK (relative gray value 0.427 7±0.003 8, P<0.000 1) protein expression was decreased in LPS+IL-33 group. Conclusion: IL-33 may improve LPS-induced hyperpermeability of RCMECs by inhibiting RhoA and p-ROCK protein expression in Rho/Rho-associated coiled-coil-containing protein kinase signaling pathway.
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The diagnostic value of contrast-enhanced ultrasound LI-RADS for hepatocellular carcinoma in patients with cirrhosis and chronic hepatitis B. Abdom Radiol (NY) 2022; 47:630-639. [PMID: 34910237 DOI: 10.1007/s00261-021-03345-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 12/12/2022]
Abstract
PURPOSE To explore the diagnostic value of American College of Radiology Contrast-Enhanced Ultrasound-Liver Imaging Reporting and Data System (ACR-CEUS-LI-RADS) for hepatocellular carcinoma (HCC) in patients with cirrhosis and chronic hepatitis B. METHODS A total of 205 patients at high risk of HCC with solitary hepatic nodule were enrolled and retrospectively analyzed. All patients were over 18 years old and had a single lesion with a diameter < 50 mm. Lesions were categorized according to size and contrast enhancement patterns in the arterial, portal venous and late phases. Diagnostic efficacy of CEUS LI-RADS for HCC, and the rate of non-HCC malignancies in the LR-M class were compared between patients with cirrhosis and chronic hepatitis B. RESULTS Of all 205 nodules (median nodule size was 34 mm), 142 (69.3%) were HCC. Of the 127 (61.9%) LR-5 category nodules, 95.8% (92/96) nodules were corresponded to HCC in cirrhosis, while 61.3% (19/31) nodules were corresponded to HCC in chronic hepatitis B (P = 0.000). Positive predictive value (PPV) of LR-5 category for HCC was 95.8% in cirrhosis and 61.3% in chronic hepatitis B (P = 0.000). More category of LR-4 nodules were proved to be HCC in patients with cirrhosis than chronic hepatitis B (80.0% vs 8.3%, P = 0.000). Of 41 LR-M category nodules, more non-HCC malignancies were found in chronic hepatitis B (76.0%) than that in cirrhosis (25.0%, P = 0.001). CONCLUSIONS The LR-5 category is highly specific for the diagnosis of HCC in patients with cirrhosis. However, LR-5 category nodules require further CT or MRI examination or histological confirmation in patients with chronic hepatitis B for its unsatisfactory PPV for HCC.
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Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission. PHYSICAL REVIEW LETTERS 2021; 126:201102. [PMID: 34110215 DOI: 10.1103/physrevlett.126.201102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/25/2021] [Accepted: 04/06/2021] [Indexed: 06/12/2023]
Abstract
The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.
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Perfusion Characteristics of Hepatocellular Carcinoma at Contrast-enhanced Ultrasound: Influence of the Cellular differentiation, the Tumor Size and the Underlying Hepatic Condition. Sci Rep 2018; 8:4713. [PMID: 29549368 PMCID: PMC5856788 DOI: 10.1038/s41598-018-23007-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 03/05/2018] [Indexed: 12/12/2022] Open
Abstract
This study aimed to analyze the influence of the cellular differentiation, the tumor size and the underlying hepatic condition on the enhancement pattern of hepatocellular carcinoma (HCC) on contrast-enhanced ultrasound (CEUS). 276 patients with single lesion ≤ 5 cm who underwent CEUS exam and were pathologically confirmed as HCC were retrospectively enrolled. Enhancement patterns, washout patterns, wash-in time and washout time were observed and recorded. During the arterial phase, more poorly differentiated HCCs (42.5%) and lesions > 3 cm (35.2%) performed inhomogeneous enhancement (p < 0.05). More well differentiated HCCs (63.4%) performed late washout or no washout while compared with moderately (37.8%) or poorly (24.1%) differentiated HCCs (p < 0.05). Poorly differentiated HCCs showed the shortest washout time (83.0 ± 39.8 s), moderately differentiated HCCs showed the moderate washout time (100.4 ± 52.1 s), and well differentiated HCCs showed the longest washout time (132.3 ± 54.2 s) (p < 0.05). Lesions > 3 cm (97.2 ± 51.3 s) washed out more rapidly than lesions ≤ 3 cm (113.9 ± 53.5 s) (p < 0.05). The dynamic enhancement procedure of HCC was influenced by the cellular differentiation and the tumor size. While, hepatic background showed no influence on the dynamic enhancement of HCC.
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High-mobility group box 1 released by autophagic cancer-associated fibroblasts maintains the stemness of luminal breast cancer cells. J Pathol 2017; 243:376-389. [PMID: 28802057 DOI: 10.1002/path.4958] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 07/28/2017] [Accepted: 08/01/2017] [Indexed: 01/16/2023]
Abstract
Cancer stem cells/cancer-initiating cells (CICs) and their microenvironmental niche play a vital role in malignant tumour recurrence and metastasis. Cancer-associated fibroblasts (CAFs) are major components of the niche of breast cancer-initiating cells (BCICs), and their interactions may profoundly affect breast cancer progression. Autophagy has been considered to be a critical process for CIC maintenance, but whether it is involved in the cross-talk between CAFs and CICs to affect tumourigenesis and pathological significance has not been determined. In this study, we found that the presence of CAFs containing high levels of microtubule-associated protein 1 light chain 3 (LC3II), a marker of autophagosomes, was associated with more aggressive luminal human breast cancer. CAFs in human luminal breast cancer tissues with high autophagy activity enriched BCICs with increased tumourigenicity. Mechanistically, autophagic CAFs released high-mobility group box 1 (HMGB1), which activated its receptor, Toll-like receptor (TLR) 4, expressed by luminal breast cancer cells, to enhance their stemness and tumourigenicity. Furthermore, immunohistochemistry of 180 luminal breast cancers revealed that high LC3II/TLR4 levels predicted an increased relapse rate and a poorer prognosis. Our findings demonstrate that autophagic CAFs play a critical role in promoting the progression of luminal breast cancer through an HMGB1-TLR4 axis, and that both autophagy in CAFs and TLR4 on breast cancer cells constitute potential therapeutic targets. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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TSSC3 represses self-renewal of osteosarcoma stem cells and Nanog expression by inhibiting the Src/Akt pathway. Oncotarget 2017; 8:85628-85641. [PMID: 29156746 PMCID: PMC5689636 DOI: 10.18632/oncotarget.20429] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 06/10/2017] [Indexed: 11/25/2022] Open
Abstract
Osteosarcoma is the most common type of bone cancer, and the second leading cause of cancer-related death in children and young adults. Osteosarcoma stem cells are essential for osteosarcoma initiation, metastasis, chemoresistance and recurrence. In the present study, we report that: 1) higher TSSC3 expression indicates a better prognosis for osteosarcoma patients, and; 2) overexpression of TSSC3 significantly decreases sphere-forming capacity, tumor initiation, stemness-related surface markers and Nanog expression in osteosarcoma cells. We also discovered that higher Nanog expression correlates to a worse prognosis for osteosarcoma patients, and overexpression of Nanog increases the stem-related phenotype in osteosarcoma cells. Knockdown of Nanog suppresses these phenotypes. Inhibition of Nanog expression and self-renewal of osteosarcoma cells by TSSC3 overexpression appears to be mediated through inactivation of the Src/Akt pathway. In the clinical setting, expression of TSSC3, p-Src and Nanog is associated with recurrence, metastasis and surgical intervention. Lower TSSC3 expression, higher Nanog expression or higher p-Src expression indicate a poor prognosis for osteosarcoma patients. Overall, our study demonstrates that TSSC3 inhibits the stem-like phenotype and Nanog expression by inactivation of the Src/Akt pathway; this emphasizes the importance of Nanog in osteosarcoma stem cells.
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Factors Affecting the Enhancement Patterns of Intrahepatic Cholangiocarcinoma (ICC) on Contrast-Enhanced Ultrasound (CEUS) and their Pathological Correlations in Patients with a Single Lesion. ULTRASCHALL IN DER MEDIZIN (STUTTGART, GERMANY : 1980) 2016; 37:609-618. [PMID: 25919414 DOI: 10.1055/s-0034-1399485] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Purpose: To investigate the factors that influence the enhancement patterns of intrahepatic cholangiocarcinomas (ICC) on contrast-enhanced ultrasound (CEUS) and analyze the correlations between the enhancement patterns on CEUS and pathological findings. Materials and Methods: Ninety-six patients with 96 pathologically confirmed ICCs underwent CEUS. CEUS images were retrospectively evaluated for tumor enhancement patterns in the arterial, portal and late phases. The arterial enhancement patterns were correlated with clinicopathological factors. The possible influencing factors were correlated with pathologic findings. Results: Thirty-six patients with ICC demonstrated rim-like enhancement, and 60 exhibited non-rim-like enhancement in the arterial phase on CEUS. The incidence of non-rim-like-enhancing ICCs was higher in patients with cirrhosis and chronic viral hepatitis than patients with no chronic liver disease (p = 0.001). The sizes of the ICCs with homogeneous hyper-enhancement were significantly smaller than those with inhomogeneous hyper-enhancement (p = 0.007). Arterial non-rim-like-enhancing ICCs showed higher microvessel density (MVD) and arterial density (AD) and less fibrous stroma and necrosis than rim-like-enhancing ICCs. Arterial inhomogeneous-enhancing ICCs had lower MVD and AD and much more fibrous stroma and necrosis than homogeneous-enhancing ICCs. Conclusion: The enhancement pattern of ICCs in the arterial phase on CEUS was affected by a liver cirrhosis and chronic viral hepatitis and tumor size. The amount of MVD, AD, fibrous stroma and necrosis in ICC tumors may be responsible for the difference in the enhancement patterns.
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Niacin receptor GPR109A inhibits insulin secretion and is down-regulated in type 2 diabetic islet beta-cells. Gen Comp Endocrinol 2016; 237:98-108. [PMID: 27570060 DOI: 10.1016/j.ygcen.2016.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 07/18/2016] [Accepted: 08/24/2016] [Indexed: 02/05/2023]
Abstract
OBJECTIVES We previously found niacin receptor GPR109A was expressed in murine islet beta-cells, and signaling through GPR109A inhibited glucose stimulated insulin secretion (GSIS). However, the expression of GPR109A in human islets and its functional relevance is still not known. METHODS The expression of GPR109A was examined by antibody staining and in situ hybridization on pancreatic paraffin sections. GPR109A was cloned and expressed in INS-1 islet beta-cells. Intracellular cAMP and GSIS were determined using enzyme-linked immunosorbent assay (ELISA). RESULTS The expression of GPR109A was confirmed in murine islet beta-cells and further detected in human counterparts by using commercially available polyclonal antibodies. In situ hybridization study detected the transcripts of GPR109A, but not that of closely related GPR109B. Furthermore, GPR109A was significantly reduced in islets from diabetic individuals and animal model of db/db mice as compared to their respective controls. Further, GPR109A levels in insulinoma were also reduced dramatically as compared to islets found in corresponding non-tumor normal tissues. Quantitative RT-PCR analysis demonstrated that GPR109A transcripts were severely down-regulated in rodent insulinoma cell lines as compared to that of freshly isolated islets from mice. Finally, human and murine GPR109A expression cassettes were transfected into INS-1 cells, which resulted in reduced accumulation of cAMP and insulin secretion after incubation with niacin. The effect could be completely abrogated by pretreatment with pertussis toxin. CONCLUSIONS These results demonstrate that GPR109A is functionally expressed in both human and murine islet beta-cells. However, the role of GPR109A in the prevention of diabetes or insulinoma needs further study.
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Primary hepatic neuroendocrine tumors: clinical characteristics and imaging features on contrast-enhanced ultrasound and computed tomography. Abdom Radiol (NY) 2016; 41:1767-75. [PMID: 27156080 DOI: 10.1007/s00261-016-0770-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Primary hepatic neuroendocrine tumor (PHNET) is an extremely rare liver neoplasm, and its clinical characteristics and imaging features are not well understood. The aim of this study was to analyze the clinical profiles and imaging features of PHNETs on contrast-enhanced ultrasound (CEUS) and computed tomography (CT) METHODS: Patients with PHNET between January 2008 and December 2015 were retrospectively identified, and their demographics, laboratory data, and imaging characteristics on CEUS and CT analyzed. RESULTS Ten consecutive patients with PHNETs were included (including one G1, seven G2, and two G3 of tumor grades).The median age of patient was 45 years (range: 27-72 years), and 60.0% of patients were male. The most common symptom was abdominal pain (60.0%), and cirrhosis was found in 40.0% of patients. Tumors were confined within the liver in 60.0% of patients, while the remaining patients had extra-hepatic metastasis. The tumors revealed hyperechoic in 60% of patients and mixed echoic in 30% of patients on conventional US, displaying intense arterial enhancement followed by washout in the portal and/or the late phases in 80.0% of patients on CEUS and 60% at CT. CONCLUSIONS Although PHNET is a very rare liver tumor, it should be considered as a possible differential diagnosis in the management of hepatic tumors. Most PHNETs were hyperechoic or mixed echoic on conventional US, showing similar enhancement patterns to that of hepatocellular carcinoma on CEUS.
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Dynamic enhancement patterns of intrahepatic cholangiocarcinoma in cirrhosis on contrast-enhanced computed tomography: risk of misdiagnosis as hepatocellular carcinoma. Sci Rep 2016; 6:26772. [PMID: 27226026 PMCID: PMC4880940 DOI: 10.1038/srep26772] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/06/2016] [Indexed: 12/16/2022] Open
Abstract
This study aimed to assess the features of intrahepatic cholangiocarcinoma (ICC) at
computerized tomography (CT) and verify the risk of misdiagnosis of ICC as
hepatocellular carcinoma (HCC) in cirrhosis. CT appearances of 98 histologically
confirmed ICC nodules from 84 cirrhotic patients were retrospectively reviewed,
taking into consideration the pattern and dynamic contrast uptake during the
arterial, portal venous and delayed phases. During the arterial phase, 53 nodules
(54.1%) showed peripheral rim-like enhancement, 35 (35.7%) hyperenhancement, 9
(9.2%) hypoenhancement and 1 (1.0%) isoenhancement. The ICC nodules showed
heterogeneous dynamic contrast patterns, being progressive enhancement in 35 nodules
(35.7%), stable enhancement in 28 nodules (28.6%), wash-in and wash-out pattern in
15 nodules (15.3%) and all other enhancement patterns in 20 nodules (20.4%). There
were no significant differences in the dynamic vascular patterns of ICC according to
nodule size (p > 0.05). ICC in cirrhosis has
varied enhancement patterns at contrast-enhanced multiphase multidetector CT. Though
the majority of ICC did not display typical radiological hallmarks of HCC, if
dynamic CT scan was used as the sole modality for the non-invasive diagnosis of
nodules in cirrhosis, the risk of misdiagnosis of ICC for HCC is not negligible.
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Combined hepatocellular carcinoma and cholangiocarcinoma (biphenotypic) tumors: clinical characteristics, imaging features of contrast-enhanced ultrasound and computed tomography. BMC Cancer 2016; 16:158. [PMID: 26917546 PMCID: PMC4768404 DOI: 10.1186/s12885-016-2156-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/10/2016] [Indexed: 02/06/2023] Open
Abstract
Background Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is an uncommon primary liver malignancy and little known about the clinical and imaging characteristics of cHCC-CC. We aim to define the demographics, imaging features of cHCC-CC on contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CT) in this study. Methods From January 2005 to December 2014, 45 patients with pathologically proven cHCC-CC who underwent preoperative CEUS and 43 patients who had additional CT scan in our institution were included. A retrospective review of the imaging studies and clinical data in these patients was conducted. Results In our series, cHCC-CC accounted for 1.6 % of all primary liver malignancy. Mean age of patient with cHCC-CC was 52.8 year (range: 28–74 year) and 88.9 % (40/45) of patients were male. Thirty of forty five patients (66.7 %) had cirrhosis and 20 % (9/45) of patients had chronic hepatitis B without cirrhosis. Alpha--fetoprotein (AFP) was elevated in 62.2 % (28/45) of patients and carbohydrate antigen 19–9 (CA19-9) elevated in 22.2 % (10/45) of patients). Both AFP and CA19-9 were simultaneously elevated in 15.6 % (7/45) of patients. Enhancement pattern resembling cholangiocarcinoma (CC) was noted in 53.3 % (24/45) of patients (on CEUS and in 30.2 % (13/43) of patients at CT. Enhancement pattern resembling hepatocellular carcinoma (HCC) was observed in 42.2 % (19/45) of patients on CEUS and in 58.1 % (25/43) of patients at CT. The percentage of tumors showing CC enhancement pattern (27.9 %, 12/43) was comparable with that of tumors showing HCC enhancement pattern (44.2 %, 19/43) on both CEUS and CT (p = 0.116). Simultaneous elevation of tumor markers (AFP and CA19-9) or tumor marker elevation (AFP or CA19-9) in discordance with enhancement pattern on CEUS was demonstrated in 51.1 % (23/45) of patients and on CT in 53.5 % (23/43) of patients, which was significantly more than simultaneous elevation of tumor markers (AFP and CA19-9) alone (p = 0.000). Conclusions The clinical characteristics of cHCC-CC are similar to those of HCC. The cHCC-CC tumors display enhancement patterns resembling CC or HCC in comparable proportion on both CEUS and CT. Combination of simultaneous elevation of tumor makers (AFP and CA19-9) and tumor mark elevation (AFP or CA19-9) in discordance with presumptive imaging findings on CEUS or CT may lead significantly more patients to be suspicious of the diagnosis of cHCC-CC.
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Diagnosis of Hepatic Angiomyolipoma by Combination of Baseline and Contrast-Enhanced Ultrasound--A Prospective Study in Non-Cirrhotic Patients. PLoS One 2015; 10:e0132290. [PMID: 26147859 PMCID: PMC4492985 DOI: 10.1371/journal.pone.0132290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 06/11/2015] [Indexed: 12/14/2022] Open
Abstract
Objectives Hepatic angiomyolipoma (HAML) is a rare, benign mesenchymal tumor of the liver and its diagnosis has been considered challenging. The aim of this study was to investigate prospectively the diagnostic efficacy of the incorporation of both baseline ultrasound (US) and contrast-enhanced ultrasound (CEUS) features of HAML in patients without cirrhosis. Materials and Methods Consecutive 1748 non-cirrhotic patients with focal liver lesions (FLLs) were prospectively enrolled. Baseline US and CEUS were performed before resection or biopsy. Ultrasound imaging diagnosis of FLLs was compared with the pathological results. Results Final diagnoses were established in 41 patients with HAML (2.3%) with normal alpha fetal protein (AFP) level and in 1707 patients with FLL other than HAML. Diagnostic criteria for HAML was based on the combination of baseline US and CEUS appearance of the nodule: (1) Well-defined, marked hyper-echoic nodule without surrounding hypo-echoic halo on baseline US; (2) hyper-enhancement in the arterial phase (exclude initial peripheral nodular enhancement and spoke-wheel arteries) and remains hyper-enhancement or iso-enhancement in the late phase. The diagnostic criteria were fulfilled in 31 HAMLs, 1 hepatocellular adenoma and 1 hemangioma. Ten HAMLs were misdiagnosed as other liver tumors because they did not meet the diagnostic criteria mentioned above and consequently yielded a sensitivity, specificity, positive predictive values, negative predictive values and Youden index of 75.61%, 99.88%, 93.94%, 99.42%, and 0.75 respectively. Conclusion The combination of baseline US and CEUS may lead to the correct diagnosis noninvasively in the majority of HAMLs in non-cirrhotic patients with normal AFP level.
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Endothelial cells promote stem-like phenotype of glioma cells through activating the Hedgehog pathway. J Pathol 2014; 234:11-22. [PMID: 24604164 PMCID: PMC4260128 DOI: 10.1002/path.4349] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 01/05/2023]
Abstract
Microenvironmental regulation of cancer stem cells (CSCs) strongly influences the onset and spread of cancer. The way in which glioma cells interact with their microenvironment and acquire the phenotypes of CSCs remains elusive. We investigated how communication between vascular endothelial cells and glioma cells promoted the properties of glioma stem cells (GSCs). We observed that CD133+ GSCs were located closely to Shh+ endothelial cells in specimens of human glioblastoma multiforme (GBM). In both in vitro and in vivo studies, we found that endothelial cells promoted the appearance of CSC-like glioma cells, as demonstrated by increases in tumourigenicity and expression of stemness genes such as Sox2, Olig2, Bmi1 and CD133 in glioma cells that were co-cultured with endothelial cells. Knockdown of Smo in glioma cells led to a significant reduction of their CSC-like phenotype formation in vitro and in vivo. Endothelial cells with Shh knockdown failed to promote Hedgehog (HH) pathway activation and CSC-like phenotype formation in co-cultured glioma cells. By examination of glioma tissue specimens from 65 patients, we found that the survival of glioma patients was closely correlated with the expression of both Shh by endothelial cells and Gli1 by perivascular glioma cells. Taken together, our study demonstrates that endothelial cells in the tumour microenvironment provide Shh to activate the HH signalling pathway in glioma cells, thereby promoting GSC properties and glioma propagation. © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Detailed analysis of temporal features on contrast enhanced ultrasound may help differentiate intrahepatic cholangiocarcinoma from hepatocellular carcinoma in cirrhosis. PLoS One 2014; 9:e98612. [PMID: 24874413 PMCID: PMC4038593 DOI: 10.1371/journal.pone.0098612] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/05/2014] [Indexed: 12/18/2022] Open
Abstract
Aim To verify if detailed analysis of temporal enhancement patterns on contrast enhanced ultrasound (CEUS) may help differentiate intrahepatic cholangiocarcinoma (ICC) from hepatocellular carcinoma (HCC) in cirrhosis. Methods Thirty three ICC and fifty HCC in cirrhosis were enrolled in this study. The contrast kinetics of ICC and HCC was analyzed and compared. Results Statistical analysis did not reveal significant difference between ICC and HCC in the time of contrast first appearance and arterial peak maximum time. ICC displayed much earlier washout than that of HCC (47.93±26.45 seconds vs 90.86±31.26 seconds) in the portal phase, and most ICC (87.9%) showed washout before 60 seconds than HCC (16.0%). Much more ICC (78.8%) revealed marked washout than HCC (12.0%) while most HCC (88.0%) showed mild washout or no washout in late part of the portal phase (90–120 seconds). Twenty six out of thirty three ICC (78.8%) demonstrated both early washout(<60seconds) and marked washout in late part of the portal phase, whereas, only six of fifty HCC (12.0%)showed these temporal enhancement features (p = 0.000).When both early washout and marked washout in the portal phase are taken as diagnostic criterion for ICC, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 78.8%,88.0%,81.3%,86.3%,and 84.3% respectively by CEUS. Conclusions Analysis of detailed temporal enhancement features on CEUS is helpful differentiate ICC from HCC in cirrhosis.If a nodule in cirrhotic liver displays hyper-enhancement in the arterial phase followed by early and marked washout in the portal phase, the nodule is highly suspicious of ICC rather than HCC.
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Abstract
Object
The authors undertook this study to establish an animal model to investigate the pathophysiological changes of venous hypertensive myelopathy (VHM).
Methods
This study was a randomized control animal study with blinded evaluation. The VHM model was developed in 24 adult New Zealand white rabbits by means of renal artery and vein anastomosis and trapping of the posterior vena cava; 12 rabbits were subjected to sham surgery. The rabbits were investigated by spinal function evaluation, abdominal aortic angiography, spinal MRI, and pathological examination of the spinal cord at different follow-up stages.
Results
Twenty-two (91.67%) of 24 model rabbits survived the surgery and postoperative period. The patency rate of the arteriovenous fistula was 95.45% in these 22 animals. The model rabbits had significantly decreased motor and sensory hindlimb function as well as abnormalities at the corresponding segments of the spinal cord. Pathological examination showed dilation and hyalinization of the small blood vessels, perivascular and intraparenchymal lymphocyte infiltration, proliferation of glial cells, and neuronal degeneration. Electron microscopic examination showed loose lamellar structure of the myelin sheath, increased numbers of mitochondria in the thin myelinated fibers, and pyknotic neurons.
Conclusions
This model of VHM is stable and repeatable. Exploration of the sequential changes in spinal cord and blood vessels has provided improved understanding of this pathology, and the model may have potential for improving therapeutic results.
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Characterization and comparison of EST-SSR and TRAP markers for genetic analysis of the Japanese persimmon Diospyros kaki. GENETICS AND MOLECULAR RESEARCH 2013; 12:2841-51. [PMID: 23359055 DOI: 10.4238/2013.january.9.3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We developed and characterized expressed sequence tags (ESTs)-simple sequence repeats (SSRs) and targeted region amplified polymorphism (TRAP) markers to examine genetic relationships in the persimmon genus Diospyros gene pool. In total, we characterized 14 EST-SSR primer pairs and 36 TRAP primer combinations, which were amplified across 20 germplasms of 4 species in the genus Diospyros. We used various genetic parameters, including effective multiplex ratio (EMR), diversity index (DI), and marker index (MI), to test the utility of these markers. TRAP markers gave higher EMR (24.85) but lower DI (0.33), compared to EST-SSRs (EMR = 3.65, DI = 0.34). TRAP gave a very high MI (8.08), which was about 8 times than the MI of EST-SSR (1.25). These markers were utilized for phylogenetic inference of 20 genotypes of Diospyros kaki Thunb. and allied species, with a result that all kaki genotypes clustered closely and 3 allied species formed an independent group. These markers could be further exploited for large-scale genetic relationship inference.
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Microwave absorption of gamma'-Fe2.6 Ni1.4N nanoparticles derived from nitriding counterpart precursor. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2012; 12:3040-3047. [PMID: 22849063 DOI: 10.1166/jnn.2012.5842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Gamma-Fe2.6Ni1.4 nanoparticles were prepared by the arc-discharge method as the precursor and its nitride counterpart of gamma'-Fe2.6Ni14N nanoparticles was synthesized directly through a thermal ammonolysis reaction at the temperature of 673 K for two hours. The resultant product was identified as a homogeneous ternary nitride with nearly spherical shape and average size of about 60.0 nm. The electromagnetic characteristics of gamma'-Fe2.6Ni1.4N derivant and gamma-Fe2.6Ni1.4 precursor have been studied in the frequency range of 2-18 GHz. Compared with the precursor, gamma'-Fe2.6Ni1.4N nanoparticles exhibits an enhanced electromagnetic absorption property resulted from the increased dielectric loss by nitriding process. The optimal reflection loss (RL) of gamma'-Fe2.6Ni1.4N nanoparticles/paraffin composite can reach -39.9 dB at 5.2 GHz in a thickness of 2.29 mm, and the frequency band corresponding RL < -10 dB is over 2.6-18 GHz in the thickness range of 0.78-4.20 mm.
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Distinct mechanism of small-for-size fatty liver graft injury--Wnt4 signaling activates hepatic stellate cells. Am J Transplant 2010; 10:1178-88. [PMID: 20420630 DOI: 10.1111/j.1600-6143.2010.03102.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this study, we aimed to investigate the significance of hepatic stellate cells (HSCs) activation in small-for-size fatty liver graft injury and to explore the underlying molecular mechanism in a rat liver transplantation model. A rat orthotopic liver transplantation model using fatty grafts (40% of fatty changes) and cirrhotic recipients was applied. Intragraft gene expression profiles, ultrastructure features and HSCs activation were compared among the rats received different types of grafts (whole vs. small-for-size, normal vs. fatty). The distinct molecular signature of small-for-size fatty graft injury was identified by cDNA microarray screening and confirmed by RT-PCR detection. In vitro functional studies were further conducted to investigate the direct effect of specific molecular signature on HSCs activation. HSCs activation was predominantly present in small-for-size fatty grafts during the first 2 weeks after transplantation, and was strongly correlated with progressive hepatic sinusoidal damage and significant upregulation of intragraft Wnt4 signaling pathway. In vitro suppression of Wnt4 expression could inhibit HSC activation directly. In conclusion, upregulation of Wnt4 signaling led to direct HSC activation and subsequently induced small-for-size fatty liver grafts injury. Discovery of this distinct mechanism may lay the foundation for prophylactic treatment for marginal graft injury in living donor liver transplantation.
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[Clinical related factors of portal vein tumor thrombosis in patients with hepatocellular carcinoma: a logistic regression analysis]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 2008; 46:733-736. [PMID: 18953925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE To investigate the related factors of portal vein tumor thrombosis (PVTT) in patients with HCC. METHODS A total number of 234 patients with hepatocellular carcinoma (HCC) were included in this retrospective study. Uni-variate and multi-variate logistic regression analysis were employed to analyze the association between PVTT and 18 routine clinical parameters. RESULTS Among the 234 patients with HCC, 15% of patients (35/235) had PVTT. Univariate logistic regression analysis revealed significant association of age (P = 0.016), gamma glutamyl transferase (GGT, P = 0.003), number of segmental invasion (P = 0.007), microvascular invasion (P < 0.01), segment location of S2 (P = 0.001), S3 (P = 0.000), S4 (P = 0.004) and S6 (P = 0.016). Multivariate analysis shows potential significant predictors of PVTT in HCC were age (RR: 0.373; 95% CI: 0.146-0.954; P = 0.040), the tumor location of S3 (RR: 4.625; 95% CI: 1.916-11. 165;P = 0.001), GGT (RR: 4.091; 95% CI: 1.448-11.553; P = 0.008) and microvascular invasion (RR: 20.912; 95% CI: 4.745-92.172; P < 0.01). CONCLUSIONS PVTT occurred more commonly in the younger (< 50 years old), and those with high level of GGT, segment location of S3 and microvascular invasion.
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Induction of matrix metalloproteinase-2 and matrix metalloproteinase-9 expression in gastric cancer cells by tumor necrosis factor-α. Shijie Huaren Xiaohua Zazhi 2007; 15:1208-1212. [DOI: 10.11569/wcjd.v15.i11.1208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the inductive effect of tumor necrosis factor-α (TNF-α) on the expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in gastric cancer cells.
METHODS: Gastric cancer cells were stimulated by exogenous TNF-α and the cells without stimulation served as controls. The contents of MMP-2 and MMP-9 in the supernatant fluid of gastric cancer cells were measured by enzyme-linked immunosorbnent assay (ELISA). The expression of MMP-2 and MMP-9 mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR). Western blot was used to detect the expression of MMP-2 and MMP-9 protein in gastric cancer cells.
RESULTS: Following stimulation with 1, 10 and 100 mg/L TNF-α, the contents of MMP-2 (8.24 ± 1.36, 23.65 ± 3.45, 14.83 ± 2.54 ng/L) and MMP-9 (12.47 ± 2.66, 34.12 ± 6.78, 23.31 ± 4.45 ng/L) in the supernatant fluid of gastric cancer cells were increased significantly as compared with those in the control group (MMP-2: 1.56 ± 0.23 ng/L; 5.25 ± 0.89 ng/L; all P < 0.01). After 16 h of stimulation with TNF-α, the contents of MMP-2 and MMP-9 in the supernatant fluid reached the peak values, which were 23.65 ± 3.45 and 34.12 ± 6.78 ng/L, respectively. MMP-2 and MMP-9 expression were up-regulated both at mRNA and protein level.
CONCLUSION: TNF-α can up-regulate the expression of MMP-2 and MMP-9 in gastric cancer cells.
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[Inhibited proliferation and expression of human nasopharyngeal carcinoma line induced by celecoxib in vitro]. ZHONGHUA ER BI YAN HOU TOU JING WAI KE ZA ZHI = CHINESE JOURNAL OF OTORHINOLARYNGOLOGY HEAD AND NECK SURGERY 2006; 41:809-12. [PMID: 17283531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
OBJECTIVE To study the effects of celecoxib on the cell proliferation and expression of vascular endothelial growth factor (VEGF) in human nasopharyngeal carcinoma line. METHODS 3-[ 4,5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) test was used to investigate the cell proliferation. Flow cytometry (FCM) was used to analyze the cell cycle arrest. Immunocytochemistry technique was to observe the expression of VEGF. RESULTS Celecoxib inhibited the growth of nasopharyngeal carcinoma line, the cell number of G0/G1 phase increased from 62.13% to 91.35%, and the cell number of G2/M and S phase decreased from 21.59% to 3.56% and from 16.28% to 5.01%, respectively, cell cycle progression was arrested at G1/S phase. Celecoxib decreased the positive expression of VEGF in HNE-1 cells. CONCLUSIONS Celecoxib inhibited the proliferation of nasopharyngeal carcinoma significantly and the expression of VEGF.
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[Relative functional changes in neutrophils in early period of acute lung injury in rabbit]. ZHONGGUO WEI ZHONG BING JI JIU YI XUE = CHINESE CRITICAL CARE MEDICINE = ZHONGGUO WEIZHONGBING JIJIUYIXUE 2004; 16:403-8. [PMID: 15238175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
OBJECTIVE To explore the relationship of interleukin-8 (IL-8), adherence function of neutrophil (PMN) and acute lung injury (ALI). METHODS Eighteen male New Zealand rabbits were divided into two groups randomly: the control group (n=8) and the ALI group (n=10). The model of ALI was replicated by using intravenous lipopolysaccharide (LPS) in the rabbits of group ALI. Blood pressure, heart rate, blood gas analysis, hemogram, CD11b expression intensity on the surface of PMN, concentration of serum IL-8 and malondialdehyde (MDA) were measured at each time point. Specimens for pathology were obtained at the end of experiment. RESULTS In group ALI, blood pressure, heart rate and pH declined obviously. PMN count was lowered obviously at 3 hours and increased at 6 hours to some extent. CD11b expression intensity on the surface of PMN, the concentration of serum IL-8 and MDA were increased progressively (all P<0.05). The main changes in the microscopic examination were inflammatory granulocyte infiltration, disseminated thickening of alveolar septa and focal hemorrhages. There were significant correlations between CD11b and IL-8 (r2=0.813, Y=26.729X), and between CD11b and the grades of pathological changes at 6 hours after intravenous LPS (r2=0.771, Y=0.011 02X+5.292). CONCLUSION LPS could induce the release of large amount of IL-8, and it activates the expression of CD11b on the surface of PMN, which shows high degree of correlation with IL-8 and the degree of pathological changes in the lung. Therefore, both of them could serve as sensitive indexes for the diagnosis of ALI.
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Algebraic direct methods for few-atoms structure models. Acta Crystallogr A 2002; 58:361-9. [PMID: 12089459 DOI: 10.1107/s0108767302005597] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2001] [Accepted: 03/26/2002] [Indexed: 11/10/2022] Open
Abstract
As a basis for direct-methods phasing at very low resolution for macromolecular crystal structures, normalized structure-factor algebra is presented for few-atoms structure models with N = 1, 2, 3, em leader equal atoms or polyatomic globs per unit cell. Main results include: [see text]. Triplet discriminant Delta(hk) and triplet weight W(hk) parameters, a approximately 4.0 and b approximately 3.0, respectively, were determined empirically in numerical error analyses. Tests with phases calculated for few-atoms 'super-glob' models of the protein apo-D-glyceraldehyde-3-phosphate dehydrogenase (approximately 10000 non-H atoms) showed that low-resolution phases from the new few-atoms tangent formula were much better than conventional tangent formula phases for N = 2 and 3; phases from the two formulae were essentially the same for N > or = 4.
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[Electro physiological characteristics of single potassium channel in isolated habenula neurons]. ZHONGGUO YING YONG SHENG LI XUE ZA ZHI = ZHONGGUO YINGYONG SHENGLIXUE ZAZHI = CHINESE JOURNAL OF APPLIED PHYSIOLOGY 2001; 17:239-270. [PMID: 21189619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Globbic approximation in low-resolution direct-methods phasing. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2000; 56:1148-55. [PMID: 10957633 DOI: 10.1107/s0907444900008362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2000] [Accepted: 06/09/2000] [Indexed: 11/10/2022]
Abstract
Probabilistic direct-methods phasing theory, originally based on a uniform atomic distribution hypothesis, is shown to be adaptable to a non-uniform bulk-solvent-compensated globbic approximation for protein crystals at low resolution. The effective number n(g) of non-H protein atoms per polyatomic glob increases with decreasing resolution; low-resolution phases depend on the positions of only N(g) = N(a)/n(g) globs rather than N(a) atoms. Test calculations were performed with measured structure-factor data and the refined structural parameters from a protein crystal with approximately 10 000 non-H protein atoms per molecule and approximately 60% solvent volume. Low-resolution data sets with d(min) ranging from 15 to 5 A gave n(g) = ad(min) + b, with a = 1.0 A(-1) and b = -1.9 for the test case. Results of tangent-formula phase-estimation trials emphasize that completeness of the low-resolution data is critically important for probabilistic phasing.
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Bulk-solvent correction in direct-methods phasing. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2000; 56:451-7. [PMID: 10739918 DOI: 10.1107/s0907444900000573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
It is shown that for crystals of large proteins at low diffraction resolution, with N approximately 10 000 independent non-H protein atoms and d(min) approximately 8 A, a simple bulk-solvent correction yields the Sayre equation in its classical form, F(h) = q summation operator(k)F(k)F(h - k). In the low-resolution protein case, the proportionality factor becomes q = 1/[(<rho(P) > - rho(S))V], where V is the unit-cell volume, rho(S) is the assumed constant electron density in the solvent regions of the crystal and <rho(P)> is the average electron density in the protein regions. The classical form of the tangent formula follows from the bulk-solvent-corrected Sayre equation and its validity at low resolution is verified in empirical calculations.
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On 'globbicity' of low-resolution protein structures. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 1999; 55:230-7. [PMID: 10089414 DOI: 10.1107/s0907444998008208] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/1997] [Accepted: 06/10/1998] [Indexed: 11/10/2022]
Abstract
Using Harker's [Harker (1953). Acta Cryst. 6, 731-736] idea of spherically averaged polyatomic groups or 'globs' as the units of structure suitable for analyzing low-resolution diffraction data from protein crystals, 'globbic' scattering factors have been calculated for main-chain peptide units and amino-acid side-chain groups to 3 A resolution via Debye's [Debye (1915). Ann. Phys. (Leipzig), 46, 809-823] scattering formula. It is shown that the scattering factors are insensitive to intra-globbic conformational variation and can be approximated fairly well by a single-Gaussian formula, i.e. fg(s) = Zg exp(-1.7Zgs2), where s = (sin theta)/lambda and Zg is the total electron count for the atoms of the glob. Phase errors due to the globbic approximation and their effect on electron-density maps at 3.5 A resolution have been assessed via calculations for the crambin structure; this analysis indicates that the globbic scattering factors will be useful in efforts to develop procedures for direct-methods phasing of diffraction data to approximately 3.5 A resolution from protein crystals.
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On integrating the techniques of direct methods with anomalous dispersion. IV. A simplified perturbation treatment for SAS phasing. Acta Crystallogr A 1997; 53 ( Pt 1):74-83. [PMID: 9037748 DOI: 10.1107/s0108767396011993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Results from probabilistic theory for the single-wavelength anomalous-scattering (SAS) Friedel pair, two-phase structure invariants, psi H = phi H + phi-H, are used to show that the SAS three-phase structure invariants, psi HK = phi H + phi K + phi-H-K, tend to positive values that are easily estimated. Appropriate averages of the estimates provide SAS perturbation corrections in the form of positive origin shifts for the probability distribution of psi HK values and for the tangent formula. The theoretical probabilistic results are verified by empirical statistical analyses of model-calculated phases and experimentally measured structure-factor magnitudes for a small-molecule and a protein crystal structure.
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Statistical Expectation Value of the Debye–Waller Factor and E(hkl) Values for Macromolecular Crystals. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 1996; 52:257-66. [PMID: 15299698 DOI: 10.1107/s0907444995014053] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
If the unit-cell distribution of atomic mean-square displacement parameters B = 8pi(2)<u(2)> is assumed to be normal, with mean micro = <B> and variance sigma(2) = <(B-<B >)(2)>, the statistical expectation value of the Debye-Waller factor W(2) = exp(-2Bs(2)), where s = (sin theta)/lambda, is <W(2)> = exp[-2( micro - sigma(2)s(2))s(2)]. This result has been incorporated into procedures for scaling and normalizing measured Bragg intensities to their Wilson expectation values. The procedures can determine both isotropic micro (B) and sigma(B) and anisotropic micro (U(ij)) and sigma(U(ij) distribution parameters. Tests with experimental data and refined structural models for several protein crystals show that the procedures yield reliable normalized structure-factor amplitudes for direct-methods applications, with values of R = summation operator (h)||E(o)| - |E(c)||/ summation operator (h)|E(o)| averaging approximately 5%.
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Abstract
At 3 to 4 A resolution, the electron density of a protein may be modeled by a continuous chain of 'globs' representing the amide region of the peptide backbone and the side-chain residues. Group scattering factors are derived from a trans planar C alpha C = ONC alpha backbone segment and most favored side-chain conformer for 18 different amino acids. Trial calculations indicate that the phase error and crystallographic residual comparing the atomic and 'globic' models rapidly decrease from high to low resolution. At 3 A resolution, the phase error is approximately 80 degrees. These results indicate that the electron density of a protein composed of N amino acid residues may be adequately modeled by 2N globs at low resolution.
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On integrating the techniques of direct methods with anomalous dispersion. III. Estimation of two-wavelength two-phase structure invariants. Acta Crystallogr A 1994; 50 ( Pt 3):307-11. [PMID: 8024726 DOI: 10.1107/s0108767393009778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
For diffraction data at two wavelengths from a crystal with anomalous scatterers, there are six types of two-phase structure invariants for Friedel pairs. Two of the six are single-wavelength invariants; the other four are mixed-wavelength invariants. It is shown that the latter can be estimated by a straightforward extension of results from the probabilistic direct-methods theory for the single-wavelength anomalous scattering case described in paper I [Hauptman (1982). Acta Cryst. A38, 632-641]. Statistical tests of the mixed-wavelength estimates are reported for small-molecule and macro-molecular examples.
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On integrating the techniques of direct methods with anomalous dispersion. II. Statistical properties of the two-phase structure invariants. Acta Crystallogr A 1991; 47 ( Pt 4):340-5. [PMID: 1910634 DOI: 10.1107/s0108767391000892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Results of a statistical study of probabilistic estimates of two-phase structure invariants (TPSI) for Friedel pairs in the case of single-wavelength anomalous scattering are reported. Numerical analysis of the TPSI sign, magnitude and error distributions shows that the concise formula for TPSI by probability theory [Hauptman (1982). Acta Cryst. A38, 632-641; Giacovazzo (1983). Acta Cryst. A39, 585-592] has desirable statistical properties. Computational results for the known structures of cocaine methiodide (N-methylcocaine iodide) and of cytochrome c550 and its PtCl2-4 derivative show that when [E[ values are large most of the signs of the TPSI are correctly determined - for [E[ greater than 1.0, 90% or more of the TPSI signs are positive as predicted - and the errors in the estimated TPSI magnitudes do not exceed approximately 10% for [E[ greater than 1.0 in the small-molecule case or approximately 50% for [E[ greater than 1.5 in the macromolecular case. These results suggest that the theory will be useful for estimating the TPSI for unknown structures.
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