Research progress and treatment of radiation enteritis and gut microbiota

Radiation enteritis is a kind of intestinal radiation injury in patients with pelvic and retroperitoneal malignancies after radiotherapy, and its occurrence and development process are very complicated. At present, studies have confirmed that intestinal microecological imbalance is an important factor in the formation of this disease. Abdominal radiation causes changes in the composition of the flora and a decrease in its diversity, which is mainly manifested by a decrease in beneficial bacterial species such as Lactobacilli and Bifidobacteria. Intestinal dysbacteriosis aggravates radiation enteritis, weakens the function of the intestinal epithelial barrier, and promotes the expression of inflammatory factors, thereby aggravating the occurrence of enteritis. Given the role of the microbiome in radiation enteritis, we suggest that the gut microbiota may be a potential biomarker for the disease. Treatment methods such as probiotics, antibiotics, and fecal microbiota transplantation are ways to correct the microbiota and may be an effective way to prevent and treat radiation enteritis. Based on a review of the relevant literature, this paper reviews the mechanism and treatment of intestinal microbes in radiation enteritis.

Effect of hybrid intensity modulated radiotherapy on the immune function of patients with locally advanced breast cancer surgery and efficacy observation / 肿瘤研究与临床

Objective:To investigate the effect of hybrid intensity modulated radiotherapy (Hy-IMRT) on immune function in patients with locally advanced breast cancer surgery and the treatment efficacy.Methods:A total of 94 patients with locally advanced breast cancer who underwent modified radical mastectomy for breast cancer and required postoperative radiotherapy in Changzhou Cancer Hospital in Jiangsu Province from January 2015 to January 2017 were selected. The patients were divided into Hy-IMRT group (observation group, 47 cases) and three-dimensional conformal radiotherapy (3DCRT) group (control group, 47 cases) according to the random number table method. The dose and related radiophysical parameters of the respective target areas of the two groups, adverse reactions during and after radiotherapy, cytokines and T lymphocyte subsets before and after radiotherapy, 3-year local recurrence rate, distant metastasis rate and mortality were observed and compared between the two groups.Results:The dose obtained by 95% (D 95%) [(4 945.6±36.1) Gy vs. (4 754.0±35.6) Gy] and target area conformity (CI) of the target volume (0.7±0.1 vs. 0.5±0.1) in the observation group were greater than those in the control group, and the differences were statistically significant (both P<0.05); the target volume of 110% of the prescription dose (V 110%) [(1.6±0.5) cm 3 vs. (8.4±1.2) cm 3], the target volume of more than 105% of the prescription dose (V 105%) [(19.3±3.5) cm 3 vs. (26.6±5.6) cm 3] and the heterogeneity index (HI) (1.1±0.1 vs. 1.3±0.1) in the observation group were all smaller than those of the control group, and the differences were statistically significant (all P < 0.05). The incidence of acute skin adverse reactions [53.2% (25/47) vs. 74.5% (35/47)] and the incidence of bone marrow suppression [40.4% (19/47) vs. 70.2% (33/47)] in the observation group were lower than those in the control group, and the differences were statistically significant (both P < 0.05). There were no significant differences in levels of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), CD4 +, CD8 +, and CD4 +/CD8 + between the two groups before radiotherapy (all P > 0.05). At the end of radiotherapy, the levels of IL-6, TNF-α and CD8 + were higher in both groups than before radiotherapy (all P < 0.05), and CD4 + and CD4 +/CD8 + were lower than before radiotherapy (both P < 0.05). The levels of IL-6, TNF-α and CD8 + in the observation group were lower than those in the control group, while the CD4 + and CD4 +/CD8 + were higher than those in the control group (all P < 0.05). The 3-year local recurrence rate [34.04% (16/47) vs. 42.55% (20/47)], distant metastasis rate [25.53% (12/47) vs. 38.30% (18/47)] and mortality rate [14.89% (7/47) vs. 19.15% (9/47)] in the observation group were lower than those in the control group, but the differences were not statistically significant (all P > 0.05). Conclusion:Compared with 3DCRT, the Hy-IMRT has less effect on the immune function of locally advanced breast cancer patients after modified radical resection, and the incidences of acute skin reaction and bone marrow adverse reaction are low.

Application of Metal Implant 16-Bit Imaging: New Technique in Radiotherapy.

OBJECTIVE: This study aimed to evaluate the computed tomography number and the variation of dose distribution based on 12-bit, 16-bit, and revised 16-bit images while the metal bars were inserted. METHODS: The phantoms containing stainless steel, titanium alloy, and aluminum bar were scanned with computed tomography. These images were reconstructed with 12-bit and 16-bit imaging technologies. The "cupping artifacts" computed tomography value of the metal object revised by Matlab software was called the revised 16-bit image. The computed tomography values of these metal materials were analyzed. Two radiotherapy treatment plans were designed using the treatment plan system: (1) gantry was of 0° irradiation field and (2) gantry was of 90° and 270° for 2 opposed irradiation fields. The dose profile and dose-volume histogram of a structure of interest were analyzed in various images. The analysis was based on the radiotherapy plan differences between 3 different imaging techniques (12-bit imaging, 16-bit imaging, and revised 16-bit imaging technologies). RESULTS: For low-density metal object (computed tomography value <3071 Hounsfield unit, HU), the radiotherapy plan results were consistent based on 3 different imaging techniques. For high-density metal object (computed tomography value >3071 HU), the difference in radiotherapy plan results was obvious. The dose of 12-bit was 15.9% higher than revised 16-bit on average for the downstream of titanium rod. For stainless steel, this number reached up to 42.7%. CONCLUSION: A 16-bit imaging technology of metal implants can distinguish the computed tomography value of different metal materials. Furthermore, the revised 16-bit imaging technology can improve the dose computational accuracy of radiotherapy plan with high-density metal implants.

Metal artifact reduction through MVCBCT and kVCT in radiotherapy.

This study proposes a new method for removal of metal artifacts from megavoltage cone beam computed tomography (MVCBCT) and kilovoltage CT (kVCT) images. Both images were combined to obtain prior image, which was forward projected to obtain surrogate data and replace metal trace in the uncorrected kVCT image. The corrected image was then reconstructed through filtered back projection. A similar radiotherapy plan was designed using the theoretical CT image, the uncorrected kVCT image, and the corrected image. The corrected images removed most metal artifacts, and the CT values were accurate. The corrected image also distinguished the hollow circular hole at the center of the metal. The uncorrected kVCT image did not display the internal structure of the metal, and the hole was misclassified as metal portion. Dose distribution calculated based on the corrected image was similar to that based on the theoretical CT image. The calculated dose distribution also evidently differed between the uncorrected kVCT image and the theoretical CT image. The use of the combined kVCT and MVCBCT to obtain the prior image can distinctly improve the quality of CT images containing large metal implants.

Effect of tetrahydropalmatine on expression of Cav1. 2 in dorsal root ganglion neurons in mice with sciatic nerve chronic constriction injury / 中国药理学通报

Aim To investigate the analgesic effect of tetrahydropalmatine on Cav1 . 2 expression in the dorsal root ganglion ( DRG) of mice with sciatic nerve chronic constriction injury ( CCI ) -induced neuropathic pain. Methods Forty male C57 BL/6 mice were randomly divided into 5 groups ( n =5 ): sham group ( group S) , CCI group ( group C ) and L-THP group ( group L) . Steady mice models of neuropathic pain were es-tablished by inducing CCI of sciatic nerve. According to development of neuropathic pain in mice, L group was divided into induction period, induction with ma-intenance period and long-term low-dose group. The mice were intraperitoneally administered with 45 mg · kg-1 tetrahydropalmatine in induction ( day 0~5 ) , in-duction with maintenance ( day 0~5 , 14~19 ) period of neuropathic pain state. From the instant after opera-tion, 15 mg · kg-1 tetrahydropalmatine was injected into the long-term low-dose group once per day for 19 days. Then, the behavior changes of mice were moni-tored. Moreover, the threshold of mechanical and ther-mal stimuli was tested. In addition, the expression of Cav1 . 2 protein was detected by Western blot and im-munohistochemical staining. Results The lowest ex-pression of Cav1 . 2 was observed in group C and the highest expression level of Cav1 . 2 was found in group S. Cav1. 2 expression was significantly up-regulated in induction period group, induction with maintenance period group and long-term low-dose group ( P0. 05 ) in long-term low-dose group. Conclusions High dose of tet-rahydropalmatine in induction period group, induction with maintenance period group and low-dose among the whole experiment process obviously relieves the neuro-pathic pain induced by nerve injury. The analgesic effect of tetrahydropalmatine on neuropathic pain may be due to the increased expression of Cav1 . 2 protein in DRG neurons.