P53-response circRNA_0006420 aggravates lung cancer radiotherapy resistance by promoting formation of HUR/PTBP1 complex.

BACKGROUND: p53 wild-type lung cancer cells can develop radiation resistance. Circular RNA (circRNA) consists of a family of transcripts with exclusive structures. circRNA is critical in tumorigenesis and is a potential biomarker or therapeutic target. It is uncertain how circRNA expression and functions are regulated post-radiation in p53 wild-type cancer cells. METHODS: A549 or H1299 cells were divided into p53-wt and p53-KO groups by CRISPR/Cas9; both groups were subjected to 4 Gy ionizing radiation (IR: p53-wt-IR and p53-KO-IR). RNA-seq, CCK8, cell cycle, and other functional and mechanism experiments were performed in vivo. p53 gene knockout mice were generated to test the cell results in vitro. RESULTS: circRNAs were found in differential groups. circRNA_0006420 (IRSense) was upregulated in p53-wt cells but had the same expression level as p53-KO cells after radiation, indicating that p53 silencing prevents its upregulation after IR. In the presence of p53, upregulated IRSense post-radiation induces G2/M arrest by regulating DNA damage repair (DDR) pathway-related proteins. Meanwhile, upregulated IRSense post-radiation aggravates the radiation-induced epithelial-mesenchymal transition (EMT). Interestingly, in the presence of p53, it promotes IRSense/HUR/PTBP1 complex formation resulting in the promotion of the radiation-induced EMT. Moreover, c-Jun regulates the upregulation of p53 transcription after radiation treatment. For these lung cancer cells with p53, upregulated IRSense aggravates lung cancer cell proliferation and increases radiation resistance by interacting with HUR (ElAV-like protein 1) and PTBP1 (polypyrimidine tract-binding protein 1) in the nucleus. CONCLUSIONS: Lung cancer cells retaining p53 may upregulate circRNA_0006420 (IRSense) expression post radiation to form an IRSense/HUR/PTBP1 complex leading to radiotherapy resistance. This study furthers our understanding of the roles of circRNA in regulating the effect of radiotherapy and provides novel therapeutic avenues for effective clinical lung cancer therapies.

Total Glucosides of Paeony Regulate Immune Imbalance Mediated by Dermal Mesenchymal Stem Cells in Psoriasis Mice.

OBJECTIVE: To investigate the therapeutic effects of total glucosides of paeony (TGP) on psoriasis based on the immunomodulatory effect of dermal mesenchymal stem cells (DMSCs). METHODS: A total of 30 male BALB/c mice were divided into 6 groups (n=5 in each) by a random number table method, including control, psoriasis model (model, 5% imiquimod cream 42 mg/d), low-, medium- and high-dose TGP (50, 100, and 200 mg/kg, L, M-, and H-TGP, respectively), and positive control group (2.5 mg/kg acitretin). After 14 days of continuous administration, the skin's histopathological changes, apoptosis, secretion of inflammatory cytokines, and proportion of regulatory T cells (Treg) and T helper cell 17 (Th17) were evaluated using hematoxylin-eosin (HE) staining, TdT-mediated dUTP nick end labeling staining, enzyme-linked immunosorbent assay, and flow cytometry, respectively. DMSCs were further isolated from the skin tissues of normal and psoriatic mice, and the cell morphology, phenotype, and cycle were observed. Furthermore, TGP was used to treat psoriatic DMSCs to analyze the effects on the DMSCs immune regulation. RESULTS: TGP alleviated skin pathological injury, reduced epidermis layer thickness, inhibited apoptosis, and regulated the secretion of inflammatory cytokines and the proportion of Treg and Th17 in the skin tissues of psoriatic mice (P<0.05 or P<0.01). There was no significant difference in cell morphology and phenotype between control and psoriatic DMSCs (P>0.05), however, more psoriatic DMSCs remained in G0/G1 phase compared with the normal DMSCs (P<0.01). TGP treatment of psoriatic DMSCs significantly increased cell viability, decreased apoptosis, relieved inflammatory response, and inhibited the expression of toll-like receptor 4 and P65 (P<0.05 or P<0.01). CONCLUSION: TGP may exert a good therapeutic effect on psoriasis by regulating the immune imbalance of DMSCs.

Long-term LDR exposure may induce cognitive impairments: A possible association through targeting gut microbiota-gut-brain axis.

Environmental and occupational low-dose radiation (LDR) exposure may be harmful for health but the previous reports regarding effect of LDR on cognition are contradictory. Here we investigated the effect of long-term LDR exposure on cognition. In this study, male Balb/c mice' cognitive functions were tested at 15 weeks after being exposed to 0.5 Gy LDR in 10 fractions at each dose of 0.05 Gy. The results demonstrated that long-term LDR exposure increases escape latency and the time spent in finding exits in mice compared with non LDR exposure. Meanwhile, the inflammation-related proteins including NFκB and p38 also increased. Lipopolysaccharide (LPS) increased and short-chain fatty acid (SCFA) levels decreased following long term LDR exposure. Treatment with microbiota-derived LPS and SCFAs reversed these effects in mice. Furthermore, the gut barrier integrity was damaged in a time-dependent manner with the decreased expression of intestinal epithelial-related biomarkers such as ZO-1 and occludin. Mechanistically, long after exposure to LDR, increased LPS levels may cause cognitive impairment through the regulation of Akt/mTOR signaling in the mouse hippocampus. These findings provide new insight into the clinical applications of LDR and suggest that the gut microbiota-plasma LPS and SCFAs-brain axis may underlie long-term LDR-induced cognition effects.

Enhanced Effect of Qing-Ying Decoction Concurrent with Secukinumab in the Treatment of Plaque Psoriasis.

Both Qing-Ying decoction (QYD), a Traditional Chinese Medicine (TCM), and secukinumab, a fully humanized anti-interleukin-17A monoclonal antibody, have been used to treat patients with plaque psoriasis. The combined application of TCM and biologics in the treatment of psoriasis, however, has not been investigated. We enrolled a total of 68 patients with plaque psoriasis in our prospective study, and randomly assigned them to either the study group (treated with secukinumab plus QYD), or the control group (treated with secukinumab alone). After 12- and 16-week treatment, the Psoriasis Area and Severity Index (PASI) score and the TCM score were significantly reduced in both the study and the control groups. However, the reduction in PASI and TCM scores was more significant in the study group than in the control group (12-week: PASI: 5.29 ± 0.27 vs 8.87 ± 0.38, respectively; P < .01; TCM: 5.83 ± 0.21 vs 12.39 ± 1.23, respectively; P < .01; 16-week: PASI score: 4.76 ± 0.18 vs 8.36 ± 0.31, respectively; TCM score: 4.98 ± 0.19 vs 11.27 ± 1.13, respectively; P < .01). The total treatment efficacy rate was significantly higher in the study group (97.1%) than the control group (76.5%; P = .012). The number of CD3+ and CD4+ T cells was increased, while the number of CD8+ T cells was decreased after treatment in both groups, with more significant changes in the study group (P < .01). QYD may enhance the therapeutic outcome of secukinumab in the treatment of plaque psoriasis by further suppressing chronic skin inflammation, as well as reducing adverse events and patients' psychological stress.

The Curative Effect of Pregabalin in the Treatment of Postherpetic Neuralgia Analyzed by Deep Learning-Based Brain Resting-State Functional Magnetic Resonance Images.

This work aimed to investigate the brain resting-state functional magnetic resonance imaging (fMRI) technology based on the depth autoencoders algorithm and to evaluate the clinically curative effect of pregabalin in the treatment of postherpetic neuralgia (PHN). In this study, 40 patients with PHN were selected and rolled randomly into a treatment group and a control group (20 cases in each group). Then, a depth autoencoders algorithm was constructed and applied in the brain resting-state fMRI technology. The brains of 40 patients with PHN treated with pregabalin were scanned, and the time curve extracted from MRI images was convolved by linear drift removal bandpass filtering to reduce low-frequency drift and high-frequency noise, so the low-frequency amplitude was calculated. Based on the low-frequency amplitude method, the calculated low-frequency signal energy was eventually divided by the total power of the entire frequency band to obtain the low-frequency amplitude rate value. The amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (f-ALFF) before and after treatment were compared between the treatment group and the control group, and the visual analog scale (VAS) after treatment was also observed. After 4 weeks of taking the drug, the VAS scores of patients from the treatment group in the first week (6.5 ± 0.8 points), the second week (6.5 ± 0.8 points), the third week (3.1 ± 0.3 points), and the fourth week (2.3 ± 0.4 points) after treatment were lower steeply than the scores before treatment (8.3 ± 1.1 points) (P < 0.05). Resting-state fMRI images showed that the f-ALFF of the 4 brain areas in the treatment group was higher than that of the control group, mainly including the bilateral frontal lobes, bilateral parietal lobes, left parietal lobes, and right posterior cerebellar lobes. Besides, the f-ALFF of the 6 brain areas in the treatment group was lower than that of the control group, mainly including the right frontal lobe, right parietal lobe, right middle frontal gyrus, precuneus, left frontal lobe, and superior frontal gyrus. In conclusion, the resting-state fMRI technology based on the depth autoencoders algorithm could efficiently display the brain area characteristic changes of patients with PHN before and after treatment, thereby providing a reference for the diagnosis of the patient's condition.

Helicobacter pylori and Alzheimer's Disease-Related Metabolic Dysfunction: Activation of TLR4/Myd88 Inflammation Pathway from p53 Perspective and a Case Study of Low-Dose Radiation Intervention.

Gut dysbiosis is observed in Alzheimer's disease (AD) and is frequently associated with AD-induced metabolic dysfunction. However, the extent and specific underlying molecular mechanisms triggered by alterations of gut microbiota composition and function mediating AD-induced metabolic dysfunction in AD remain incompletely uncovered. Here, we indicate that Helicobacter pylori (H. pylori) is abundant in AD patients with relative metabolic dysfunction. Fecal microbiota transplantation from the AD patients promoted metabolic dysfunction in mice and increased gut permeability. H. pylori increased gut permeability through activation of the TLR4/Myd88 inflammation pathway in a p53-dependent manner, leading to metabolic dysfunction. Moreover, p53 deficiency reduced bile acid concentration, leading to an increased abundance of H. pylori colonization. Overall, these data identify H. pylori as a key promoter of AD-induced metabolic dysfunction.

Balneotherapy with Chinese herbal medicine prolongs the remission period in patients with psoriasis vulgaris.

This study aimed to evaluate whether the supplementary balneotherapy with Chinese herbal medicine (CHM) could facilitate the treatment of psoriasis vulgaris and thus be beneficial for long-term remission from the symptoms. Two hundred psoriasis vulgaris patients with moderate-to-severe plaque psoriasis from January 2013 to June 2014 were evenly divided into two groups: the consolidated therapy group (CTG) and unconsolidated therapy group (UTG); the remission period of the two groups was compared. There was no significant difference in Psoriasis Area Severity Index (PASI) score between the two groups at the beginning and the end of the treatment. However, the average remission time in CTG was 10.99 months, which was significantly longer than that of 7.94 months in UTG (P = .001). After a correction of age, course of disease, skin type as well as PASI baseline value using a COX model, we found that the risk of recurrence of psoriasis vulgaris in UTG was higher than that in the CTG (P < .001). No adverse reactions were discovered when combing the two treatments together. The combined treatment of CHM balneotherapy and narrowband ultraviolet B could significantly prolong the remission time in patients with psoriasis vulgaris.

Improving the accuracy of converting dose to medium to dose to water algorithms in small megavoltage photon fields in dose to medium based treatment planning systems.

PURPOSE: To present a formalism to improve the accuracy of converting absorbed dose to medium in medium (Dm) to absorbed dose to water in medium (Dw) in small megavoltage photon fields for different human tissues in Dm-based treatment planning systems (TPS). METHODS: Eight kinds of real human tissues were simulated to convert Dm to Dw. Four kinds of virtual water media were deliberately designed to analyze source of deviations from the conventional Bragg-Gray theory. Mass electronic stopping powers were calculated using the ESTAR code. The phase-space data was generated by the EGSnrc/BEAMnrc Monte Carlo code. The dose deposition was calculated with the EGSnrc/DOSRZnrc code. Electron fluence spectra calculated with EGSnrc/FLURZnrc code were utilized to analyze fluence perturbations and determine fluence intensity (Φw,mint) and fluence spectral shape (Φw,mS) correction factors. RESULTS: Large conversion errors of Dw using Bragg-Gray theory were observed, such as 19.65% ± 9.58% (average value ± standard deviation, type A) for inflated lung (ICRU). Fluence perturbations could be exacerbated by severe charged particle disequilibrium conditions. These deviations were caused by the synergy between tissues' different mean excitation energies and smaller mass densities compared to those of water. Adding Φw,mint and Φw,mS correction factors to modify Bragg-Gray theory could greatly reduce Dw conversion errors, within 1.00% for all tissues studied. CONCLUSIONS: The current clinically used Dw conversion algorithm in commercial Dm-based TPS isn't appropriate for some human tissues in small field dosimetry. Correction factors should be exploited to improve the accuracy.

Long non-coding RNA PCAT6 targets miR-204 to modulate the chemoresistance of colorectal cancer cells to 5-fluorouracil-based treatment through HMGA2 signaling.

Colorectal cancer (CRC) is still the third most common cancer in the world with a limited prognosis due to the chemoresistance of CRC cells to 5-fluorouracil (5-FU)-based chemotherapy. In our previous study, we revealed that miR-204 overexpression could sensitize CRC cell to 5-FU treatment through targeting HMGA2/PI3K signaling pathway; however, miR-204 expression in CRC tissues is abnormally downregulated. Long non-coding RNAs (lncRNAs) dysregulation has been reported in human diseases, including cancer. Also, lncRNA can regulate cancer cell proliferation, invasion, migration, as well as chemoresistance. LncRNA prostate cancer-associated transcript 6 (PCAT6) acts as an oncogene in many cancers; herein, PCAT6 expression was abnormally upregulated in CRC tissues and cell lines, suggesting its potential role in CRC. Further, we assessed the specific function and mechanism of PCAT6 in CRC. Furthermore, we revealed that PCAT6 knockdown attenuated CRC chemoresistance to 5-FU through miR-204/HMGA2/PI3K; miR-204 inhibition could partially reverse the effect of PCAT6 knockdown. Taken together, we demonstrate that the abnormal PCAT6 overexpression inhibits miR-204 expression in CRC, thereby promoting HMGA2/PI3K signaling activity, ultimately enhancing the chemoresistance of CRC cells to 5-FU; PCAT6 represents a promising target for dealing with CRC chemoresistance.

Dosimetric Comparisons of Volumetric Modulated Arc Therapy and Tomotherapy for Early T-Stage Nasopharyngeal Carcinoma.

PURPOSE: To compare the dosimetric differences between volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT) in treating early T-stage nasopharyngeal carcinoma (NPC). METHOD: Ten patients with early T-stage NPC who received tomotherapy using simultaneously integrated boost (SIB) strategies were replanned with VMAT (RapidArc of Varian, dual-arc). Dosimetric comparisons between the RapidArc plan and the HT plan included the following: (1) D98, homogeneity, and conformity of PTVs; (2) sparing of organs at risk (OARs); (3) delivery time and monitor units (MUs). RESULTS: (1) Compared with RapidArc, HT achieved better dose conformity (CI of PGTVnx + nd: 0.861 versus 0.818, P = 0.004). (2) In terms of OAR protection, RapidArc exhibited significant superiority in sparing ipsilateral optic nerve (Dmax: 27.5Gy versus 49.1Gy, P < 0.001; D2: 23.5Gy versus 48.2Gy, P < 0.001), contralateral optic nerve (Dmax: 30.4Gy versus 49.2Gy, P < 0.001; D2: 26.2Gy versus 48.1Gy, P < 0.001), and optic chiasm (Dmax: 32.8Gy versus 48.3Gy, P < 0.001; D2: 30Gy versus 47.6Gy, P < 0.001). HT demonstrated a superior ability to protect the brain stem (D1cc: 43.0Gy versus 45.2Gy, P = 0.012), ipsilateral temporal lobe (Dmax 64.5Gy versus 66.4 Gy, P = 0.015), contralateral temporal lobe (Dmax: 62.8Gy versus 65.1Gy, P = 0.001), ipsilateral lens (Dmax: 4.27Gy versus 5.24Gy, P = 0.009; D2: 4.00Gy versus 5.05Gy, P = 0.002; Dmean: 2.99Gy versus 4.31Gy, P < 0.001), contralateral lens (Dmax: 4.25Gy versus 5.09Gy, P = 0.047; D2: 3.91Gy versus 4.92Gy, P = 0.005; Dmean: 2.91Gy versus 4.18Gy, P < 0.001), ipsilateral parotid (Dmean: 36.4Gy versus 41.1Gy, P = 0.002; V30Gy: 54.8% versus 70.4%, P = 0.009), and contralateral parotid (Dmean: 33.4Gy versus 39.1Gy, P < 0.001; V30Gy: 48.2% versus 67.3%, P = 0.005). There were no statistically significant differences in spinal cord or pituitary protection between the RapidArc plan and the HT plan. (3) RapidArc achieved a much shorter delivery time (3.8 min versus 7.5 min, P < 0.001) and a lower MU (618MUs versus 5646MUs, P < 0.001). CONCLUSION: Our results show that RapidArc and HT are comparable in D98, dose homogeneity, and protection of the spinal cord and pituitary gland. RapidArc performs better in shortening delivery time, lowering MUs, and sparing the optic nerve and optic chiasm. HT is superior in dose conformity and protection of the brain stem, temporal lobe, lens, and parotid.

Impact of paranasal sinus invasion on advanced nasopharyngeal carcinoma treated with intensity-modulated radiation therapy: the validity of advanced T stage of AJCC/UICC eighth edition staging system.

The aim of this study was to clarify the prognostic role of paranasal sinus invasion in advanced NPC patients. Data of patients (n = 295) with advanced NPC (T3/T4N0-3 M0) treated with intensity-modulated radiation therapy were retrospectively analyzed. Staging was according to the AJCC/UICC eighth edition staging system. Overall survival (OS), local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) were calculated, and differences were compared between patients with and without paranasal sinus invasion. Multivariate analysis was used to identify the independent predictors of different survival parameters. Paranasal sinus invasion was present in 126 of 295 (42.7%) patients. Sphenoid, ethmoid, maxillary, and frontal sinus involvements were present in 123 of 295 (41.7%), 95 of 295 (32.2%), 45 of 295 (15.3%), and 0 of 295 (0%), respectively. All survival parameters were significantly better in patients without paranasal sinus invasion. When paranasal sinus invasion was reclassified as T4 instead of T3, all survival rates, other than LRFS (P = 0.156), were significantly better in the new T3 patients, and differences in all survival parameters remained nonsignificant between T3 with paranasal sinus invasion and T4 without paranasal sinus invasion patients (all P > 0.05). In multivariate analysis, paranasal sinus invasion was found to be an independent negative prognostic factor for OS, DFS, and DMFS (P = 0.016, P = 0.004, and P = 0.006, respectively), but not for LRFS (P = 0.068). Paranasal sinus invasion has prognostic value in advanced NPC. It may be reasonable to classify paranasal sinus invasion as T4 stage.

Resveratrol inhibits proliferation, promotes differentiation and melanogenesis in HT-144 melanoma cells through inhibition of MEK/ERK kinase pathway.

The present study was aimed to investigate the effect of resveratrol on the viability of HT-144 melanoma cells and formation of melanin. MTT assay was used for analysis of cell viability and western blot for determination of phospho-Mek 1/2, phospho-Erk 1/2 (Tyr-204), Mitf, PBG-D and p-CREB-1 expression. MTT assay results showed that treatment of HT-144 cells with various doses of resveratrol led to a concentration dependent inhibition of proliferation. The antiproliferative activity was significant at 15 µM concentration of resveratrol after 24 h. Western blot analysis revealed that resveratrol caused significant reduction in the expression of phospho-extracellular signal related kinase (p-ERK) and p-MEK 1/2. Additionally, tyrosinase activity was increased by 1.5-6.8-fold on increasing the concentration of resveratrol from 1 to 15 µM. Resveratrol treatment also enhanced the expression of cAMP-response element-binding proteins (CREB) after 24 h. Furthermore resveratrol treatment up-regulated porphobilinogen deaminase (PBG-D) expression in HT-144 cells. Taken together, the study demonstrates that resveratrol treatment inhibits proliferation and promotes melanogenesis of HT-144 cells through inhibition of MEK/ERK pathway. Therefore, resveratrol has a scope for further evaluation against melanogenesis.

Dosimetric comparison between intensity-modulated radiotherapy and RapidArc with single arc and dual arc for malignant glioma involving the parietal lobe.

The aim of the present study was to evaluate the difference in treatment plan quality, monitor units (MUs) per fraction and dosimetric parameters between IMRT (intensity-modulated radiotherapy) and RapidArc with single arc (RA1) and dual arc (RA2) for malignant glioma involving the parietal lobe. Treatment plans for IMRT and RA1 and RA2 were prepared for 10 patients with malignant gliomas involving the parietal lobe. The Wilcoxon matched-pair signed-rank test was used to compare the plan quality, monitor units and dosimetric parameters between IMRT and RA1 and RA2 through dose-volume histograms. Dnear-max (D2%) to the left lens, right lens and left optical nerve in RA1 were less compared with those in IMRT; D2% to the right lens and right optic nerve in RA2 were less compared with those in IMRT. D2% to the optic chiasma in RA2 was small compared with that in RA1. The median dose (D50%) to the right lens and right optic nerve in RA1 and RA2 was less compared with the identical parameters in IMRT, and D50% to the brain stem in RA2 was less compared with that in RA1. The volume receiving at least 45 Gy (V45) or V50 in normal brain tissue (whole brain minus the planning target volume 2; B-P) in RA1 was less compared with that in IMRT. V30, V35, V40, V45, or V50 in B-P in RA2 was less compared with that in IMRT. The MUs per fraction in RA1 and RA2 were significantly less compared with those in IMRT. All differences with a P-value<0.05 were considered to be significantly different. In conclusion, RA1 and RA2 markedly reduced the MUs per fraction, and spared partial organs at risk and B-P compared with IMRT.

Prognostic value of the distance between the primary tumor and brainstem in the patients with locally advanced nasopharyngeal carcinoma.

BACKGROUND: Brainstem dose limitations influence radiation dose reaching to tumor in the patients with locally-advanced nasopharyngeal cancer (NPC). METHODS: A retrospective analysis of the prognostic value of the distance between the primary tumor and brainstem (Dbs) in 358 patients with locally-advanced NPC after intensity-modulated radiation therapy (IMRT). Receiver operating characteristic (ROC) curves were used to identify the cut-off value to analyze the impact of Dbs on tumor dose coverage and prognosis. RESULTS: The three-year overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) were 88.8 vs. 78.4% (P = 0.007), 96.5 vs. 91.1% (P = 0.018), 87.8 vs. 79.3% (P = 0.067), and 84.1 vs. 69.6% (P = 0.002) for the patients with the Dbs > 4.7 vs. ≤ 4.7 mm, respectively. ROC curves revealed Dbs (4.7 mm) combined with American Joint Committee on Cancer (AJCC) T classification had a significantly better prognostic value for OS (P < 0.05). CONCLUSIONS: Dbs (≤ 4.7 mm) is an independent negative prognostic factor for OS/LRFS/DFS and enhances the prognostic value of T classification in the patients with locally-advanced NPC.

A retrospective study of the prognostic value of MRI-derived residual tumors at the end of intensity-modulated radiotherapy in 358 patients with locally-advanced nasopharyngeal carcinoma.

OBJECTIVE: To retrospectively analyze the prognostic value of magnetic resonance imaging (MRI)-derived residual tumors after intensity-modulated radiation therapy (IMRT) in the patients with locally-advanced nasopharyngeal carcinoma. METHODS: A total of 358 patients with locally-advanced nasopharyngeal carcinoma who received IMRT were classified as having residual tumors or no residual tumor based on MRI at the end of radiotherapy. The χ(2) test, log-rank test, Cox proportional hazards regression model and Kaplan-Meir survival curves were used to investigate the relationship of clinicopathological features and residual tumors and to assess the prognostic value of residual tumors. RESULTS: The 3-year overall survival (OS) rate was 73% in the residual tumor group and 90% in the no residual tumor group (HR 2.15, 95% CI 1.21-3.82,, P = 0.007); 3-year local relapse-free survival (LRFS) was 89% in the residual tumor group and 97% in the no residual tumor group (HR 4.46, 95% CI 1.61-12.38, P = 0.002); 3-year disease free survival (DFS) was 67% in the residual tumor group and 82% in the no residual tumor group (HR 2.21, 95% CI 1.40-3.48, P = 0.001). A high prescribed radiation dose (>73.92 Gy) did not increase the percentage volume of the GTVnx receiving 95% of the prescribed dose (GTVnx V95%) or improve any survival outcome. CONCLUSION: The presence of a residual tumor after IMRT was a significant negative independent prognostic factor for OS, LRFS and DFS. Although IMRT have improved the distribution of radiotherapy doses into the tumors, residual tumors detected by MRI after IMRT are still associated with poor prognosis in patients with advanced nasopharyngeal carcinoma.

[Dosimetric comparison of intensity-modulated arc radiotherapy and fixed beam dynamic intensity-modulated radiation therapy in nasopharyngeal carcinoma].

OBJECTIVE: To compare the dosimetric differences of dosiology between intensity-modulated arc radiotherapy (IMAT) and dynamic intensity-modulated radiation therapy (dIMRT) in nasopharyngeal carcinoma. METHODS: CT data from 25 patients treated in our radiotherapy center were selected randomly for this study. For each patient, the IMAT technique and the fixed beam dIMRT technique were accomplished by the simultaneously integrated boost. Dose volume histogram (DVH) data, isodose distribution, monitor units (MUs) and treatment time were compared in the two techniques. RESULTS: There was no significant difference between the IMAT and the dIMRT in dose received by 95% of target volumes (D(95)) (P>0.05). Overall, the mean dose (D(mean)), maximal dose (D(max)) and volume percentage receiving at least of 107% of the prescribed dose (V(107%)) of planning target volume (PTV) for the IMAT were increased slightly ,compared with the dlMRT (P<0.05). There were no significant differences in dosimetric indices of organs at risk (OARs) including spinal cord,optical nerves,lens and temporomandibular joints in the two techniques (P>0.05). Compared with the dlMRI, the D(max) of brain stem for the IMAT was increased slightly (P<0.05). Similar trends was observed for the D(mean) and dose received by 50% of volume (D(50)) of the left and right parotid glands (P<0.05). Healthy tissue (defined as the volume of the body minus PTV,B-P) irradiated from 800 cGy in the IMAT was higher, and that from 1200-4500 cGy was lower compared with the dlMRI (P<0.05).The average number of MUs was reduced by 62.7% per fraction, and the treatment time was on average reduced by 60.1% per fraction in the IMAT compared with the dlMRI. CONCLUSION: There is a slight difference in dosiology between the two radiotherapy techniques investigated, but they both meet the clinical requirement. Compared with the dIMRT, the IMAT delivers less irradiation to healthy tissue, uses fewer MUs and takes less time during radiotherapy for nasopharyngeal carcinoma.

The immunity induced by recombinant spike proteins of SARS coronavirus in Balb/c mice.

The immune effect of two recombinant protein fragments of spike protein in severe acute respiratory syndrome coronavirus (SARS CoV) was investigated in Balb/c mice. Two partial spike gene fragments S1 (322 1464 bp) and S2 (2170 2814 bp) of SARS coronavirus were amplified by RT-PCR, and cloned into pET-23a prokaryotic expression vector, then transformed into competent Escherichia E. coli BL21 (DE3)(pLysS) respectively. Recombinant proteins were expressed and purified by Ni2+ immobilized metal ion affinity chromatography. The purified proteins mixed with complete Freund adjuvant were injected into Balb/c mice three times at a two-week interval. High titer antibody was detected in the serum of immunized Balb/c mice, and mice immunized with S1 protein produced high titer IgG1, IgG2a, IgG2b and IgG3, while those immunized with S2 protein produced high titer IgG1, IgG2a, but lower titer IgG2b and IgG3. Serum IFN-concentration was increased significantly but the concentrations of Il-2, IL-4 and IL-10 had no significant change. And a marked increase was observed in the number of spleen CD8+ T cells. The results showed that recombinant proteins of SARS coronavirus spike protein induced hormonal and cellular immune response in Balb/c mice.

[Expression and purification of Toxoplasma gondii GRA4 gene in prokaryotic system].

OBJECTIVE: To construct a prokaryotic expression system containing the dense granule protein 4 (GRA4) of Toxoplasma gondii, purify the expressed protein and detect its immunogenicity. METHODS: The specific fragment of GRA4 gene was amplified by PCR. After subcloning the prokaryotic expression recombinant pET-GRA4, the expressed product was purified with His Bind affinity chromatography and analyzed by Western blot. BALB/c mice were immunized with the GRA4 recombinant protein, and the antibody IgG titer was detected by ELISA. RESULTS: The pET-GRA4 prokaryotic expression system was obtained. The MW of the expressed protein was Mr 40,000 and formed in inclusion body. After purification, the recombinant protein could be specifically recognized by the T. gondii infected rabbit serum. Mice immunized with the purified recombinant protein elicited high titer of IgG antibody. CONCLUSION: The pET-GRA4 recombinant protein was successfully expressed and purified, which shows the immunogenicity.