Analysis of gene variant in an infant with succinic semialdehyde dehydrogenase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with succinate semialdehyde dehydrogenase deficiency.@*METHODS@#Peripheral blood samples of the proband and his parents were collected and subjected to Sanger sequencing. High-throughput sequencing was used to verify the gene variants. Bioinformatic software was used to analyze the pathogenicity of the variant sites.@*RESULTS@#Sanger sequencing showed that the proband carried a homozygous c.1529C>T (p.S510F) variant of the ALDH5A1 gene, for which his mother was a carrier. The same variant was not detected in his father. However, high-throughput sequencing revealed that the child and his father both had a deletion of ALDH5A1 gene fragment (chr6: 24 403 265-24 566 986).@*CONCLUSION@#The c.1529C>T variant of the ALDH5A1 gene and deletion of ALDH5A1 gene fragment probably underlay the disease in the child. High-throughput sequencing can detect site variation as well as deletion of gene fragment, which has enabled genetic diagnosis and counseling for the family.

Genetic analysis of 46,XY disorders of sex development in children caused by a new NR5A1 gene variant / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with 46,XY disorders of sex development (DSD) and explore its genotype-phenotype correlation.@*METHODS@#The child was subjected to whole exome sequencing (WES), and exons 1 to 7 of NR5A1 were subjected to multiplex ligation-dependent probe amplification (MLPA) analysis.@*RESULTS@#The patient presented with rudimentary vulva of a female with Tanner stage 1. B-mode ultrasonography has detected ovary and uterus. The child was found to have a chromosome karyotype of 46,XY. WES revealed that the patient has harbored heterozygous deletion of exon 5 of the NR5A1 gene, which was a novel pathogenic variant inherited from the mother. No abnormality was found in the father.@*CONCLUSION@#The main symptoms of 46,XY DSD children are insufficient external genitalia masculinization, for which variants of the NR5A1 gene are an important cause. WES has improved the detection rate of genetic variants and provided a solid basis for genetic counseling of the affected families.

Exposure level and health risk assessment of chlorination disinfectant by-products in drinking water in Xiangyang City / 公共卫生与预防医学

Objective To understand the exposure level of disinfection by-products (DBPs) in drinking water in Xiangyang City and to evaluate the health risks of the population, so as to provide reference for the safety risk control of drinking water. Methods Sampling and laboratory testing were conducted according to national standard methods. The risk assessment model provided by USEPA was used to evaluate the health risks. Results Trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and tribromomethane (TBM) were detected in drinking water in Xiangyang City. The contents of halogenated hydrocarbon DBPs in water disinfected with liquid chlorine were higher than those with chlorine dioxide. The contents of three DBPs were higher in wet season than those in dry season except TBM. The content of TCM in pipe network terminal water and secondary water supply disinfected with chlorine dioxide was higher than that in factory water. The carcinogenic risk of DBPs in drinking water disinfected with liquid chlorine was 4.33×10-5, and the non-carcinogenic risk was 0.114. The carcinogenic risk of DBPs in drinking water disinfected with chlorine dioxide was 1.24×10-6, and the non-carcinogenic risk was 3.15×10-3. Conclusion The health risk of DBPs in drinking water in Xiangyang City is acceptable, but TCM produced by liquid chlorine disinfection should be paid more attention. It is recommended that chlorine dioxide disinfection be used to reduce the health risks of halogenated hydrocarbon DBPs.

Physics issues on plan design and evaluation for stereotactic radiotherapy based on linear accelerator / 中华放射肿瘤学杂志

Stereotactic radiotherapy (SRT), also known as stereotactic ablative radiotherapy (SABR), includes stereotactic radiosurgery and stereotactic body radiotherapy (SBRT). This technique has the characteristics of large single fractional dose, few fractions, high equivalent biological doses, and rapid fall off-target doses. It can be implemented by relatively special equipment such as Gamma knife, Cyberknife, Tomotherapy and Vero 4D RT system, etc. In many cases, SBRT technique is employed based on linear accelerators. SRT differs from conventional radiotherapy in terms of the plan design and plan evaluation. Consequently, it is necessary to discuss the differences and provide guidance for clinical application and research.

Shielding calculation and discussion on high energy light source storage ring and synchrotron / 中华放射医学与防护杂志

Objective:To verify and discuss the consistency and applicability of the semi empirical formula and Monte Carlo simulation method in the radiation shielding calculation for high energy synchrotron radiation source.Methods:The semi empirical formula and Monte Carlo simulation were used to calculate the ambient dose equivalent outside of the shielding.Results:The ratio of Jenkins semi empirical formula result to Monte Carlo simulation result was 111%-153%. The ratio of Sakano semi empirical formula result to Monte Carlo simulation result was 201%.Conclusions:For a single shielding material, the semi empirical formula can be simple and conservative to complete the shielding calculation for high-energy electron accelerator. For a variety of shielding materials, Monte Carlo simulation method should be used.

Research progress on magnetic resonance imaging-guided proton therapy for tumors / 中华放射肿瘤学杂志

With the application of magnetic resonance imaging (MRI)-guided photon therapy, the concept of combining real-time MRI guidance with proton therapy, namely, MRI-guided proton therapy (MRPT), has attracted widespread attention. It is expected that MRPT can mitigate the uncertainties during the treatment of proton therapy to make full use of the physical advantages of protons. However, multiple electromagnetic interactions between proton therapy and MRI-guided systems may lead to mutual interference between the two systems. This article review the research progress on the MRPT system, aiming to provide certain reference for the design of MRPT system.

Quality control of gross α and gross β analysis in water / 中华放射医学与防护杂志

Objective:To improve the precision and accuracy of gross radioactivity detection in water, and to improve the radiological health and environmental monitoring level of each laboratory, it is necessary to carry out method verification and quality control.Methods:The thick source method for gross α and the thin source method for gross β analysis were used to analyze the actual samples. After multiple tests, the precision of the detection was calculated. Through the spike recovery test and the comparison sample analysis of the national radiological health in 2019, the accuracy analysis of the method was performed.Results:In the precision experiment, the relative standard deviations of the gross α and gross β results were 23% and 13%, respectively. The three spike recoveries were 103.1%, 103.5%, and 105.8%, respectively. The relative errors of gross α and gross β compared with the reference value were 0.92% and 9.4%, respectively. All the result reflected the high accuracy of the method .Conclusions:The relative standard deviations, recoveries, and relative errors in the method validation and quality control were below the limits of the criterion. This work systematically discussed the major factors that may cause errors in the detection, which could further improve the level of radiological health and environmental monitoring.

"Task-based" teaching mode in tumor radiotherapy dose measurement / 中华医学教育探索杂志

Objective:To evaluate the feasibility of the "task-based" teaching mode in dose measurement of tumor radiotherapy to develop the independent practical ability of students.Methods:Twenty-one undergraduate students majoring in radiotherapy dosimetry were randomly divided into experimental group ( n=11) and control group ( n=10). The "task-based" teaching mode based on independent learning, thinking and designing was used in the experimental group, while the traditional teaching mode based on the guidance of teachers was applied in the control group. Then the practical examination of students was carried out through the case of measuring the absorbed dose of accelerator electron beam. The practical ability of the two groups of students was scored and compared by the objective and comprehensive scoring criteria. Results:The scores of each practical step and total score in the experimental group were higher than those in the control group ( P<0.05). The average total scores of the two groups were (90.18±1.97) and (83.70±3.68), respectively. Conclusion:The "task-based" practice teaching mode can improve students' ability of completing radiotherapy dose measurement independently.

Analysis of gene variant in a Chinese child affected with dihydropyrimidinase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To analyze the molecular etiology of a Chinese child affected with dihydropyrimidinase deficiency.@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the family members. Pathogenic variant was determined by whole exome sequencing and verified by Sanger sequencing.@*RESULTS@#The child was found to harbor homozygous c.905G>A (p.Arg302Gln) variants in exon 5 of the DPYS gene, for which her parents were both heterozygous carriers.@*CONCLUSION@#The homozygous c.905G>A (p.Arg302Gln) variants of the DPYS gene probably underlies the dihydropyrimidinase deficiency in the child. Above result has enabled genetic counseling and prenatal diagnosis for this family.

Prediction of rectal toxicity of radiotherapy for prostate cancer based on multi-modality feature and multi-classifiers / 南方医科大学学报

OBJECTIVE@#To evaluate rectal toxicity of radiotherapy for prostate cancer using a novel predictive model based on multi-modality and multi-classifier fusion.@*METHODS@#We retrospectively collected the clinical data from 44 prostate cancer patients receiving external beam radiation (EBRT), including the treatment data, clinical parameters, planning CT data and the treatment plans. The clinical parameter features and dosimetric features were extracted as two different modality features, and a subset of features was selected to train the 5 base classifiers (SVM, Decision Tree, K-nearest-neighbor, Random forests and XGBoost). To establish the multi-modality and multi-classifier fusion model, a multi-criteria decision-making based weight assignment algorithm was used to assign weights for each base classifier under the same modality. A repeat 5-fold cross-validation and the 4 indexes including the area under ROC curve (AUC), accuracy, sensitivity and specificity were used to evaluate the proposed model. In addition, the proposed model was compared quantitatively with different feature selection methods, different weight allocation algorithms, the model based on single mode single classifier, and two integrated models using other fusion methods.@*RESULTS@#Repeated (5 times) 5-fold cross validation of the proposed model showed an accuracy of 0.78 for distinguishing toxicity from non-toxicity with an AUC of 0.83, a specificity of 0.79 and a sensitivity of 0.76.@*CONCLUSIONS@#Compared with the models based on a single mode or a single classifier and other fusion models, the proposed model can more accurately predict rectal toxicity of radiotherapy for prostate cancer.

The relative location between the mandibular third molar and inferior alveolar canal studied by CBCT / 实用口腔医学杂志

Objective: To determine the positional relationship between impacted mandibular third molar(IMTM) and mandibular canal(MC) by CBCT. Methods: 664 IMTMs with root apexes contacted to MCs on panoramic radiograph were further examined by CBCT,the exact positional relationship between IMTMs and MCs was observed and analyzed by I-Dixel software. Results: The 664 cases were divided into lowly(6. 3％),intermediately(60. 7％) and highly(33. 0％) impacted groups by the depth of IMTMs in mandibulae showed on CBCT images. The distance(mm) from the root apexes of IMTMs to the intact superior wall of MCs(n = 329) in lowly, intermediately and highly impacted cases were 1. 39 ± 1. 38,1. 28 ± 1. 03 and 1. 79 ± 1. 54 respectively(P ＜ 0. 05). MCs on the buccal side,lingual side,under the IMTMs and between the root apexes were found in 49. 8％,12. 0％,36. 6％ and 1. 5％ of the cases; the MC wall deffect was found in 65. 8％,27. 5％ and 95. 0％ of the cases with the MCs under,on buccal and lingual side of the IMTMs, respectively(P ＜ 0. 001). Conclusion: CBCT examination is necessary for the determination of the positional relationship between MC canal and IMTM with the root apex cotacted or overlapped to MC.

Evaluation of fully automated volumetric modulated arc therapy planning of cervical cancer in RayStation treatment planning system / 中华放射医学与防护杂志

Objective To evaluate the feasibility of an in-room automated volumetric arc therapy (VMAT) planning engine based on dose volume histogram (DVH) prediction model in RayStation treatment planning system.Methods A total of 4,0 VMAT plans of cervix cancer,planned by experts,were chosen to build DVH estimation model by principal component regression analytic method.An in-room automated VMAT planning program based on IroPython scripting language combined with DVH prediction model was performed in RayStation treatment planning system.The DVH estimation model was applied to Another 10 testing cases of cervical cancer and the feasibility was evaluated by comparing the automatic plans with manual plans.Results The predicted DVH of organs at risk showed a good fit with real DVH in the ten testing cases.There were no statistically significant differences between manual and automatic plans in PTV conformal index (CI) and homogeneity index (HI) (P ＞ O.05).V40 and V50 of bladder were significantly decreased by 4.3％ and 1.6％ in automatic plans (t =2.75,5.26,P ＜ 0.05).V30,V40 and Vs0 of rectum were also decreased by 6.8％,5.8 ％ and 2.1％ (t =2.26,3.55,5.19,P ＜ 0.05).Both left and right femoral heads were better spared in automatic plans with average doses decreased by 380 and 322 cGy(t =5.55,7.25,P ＜ 0.05).The time of creating a treatment plan was 36 min for automatic plan and 53 min for manual plan.Conclusions The fully automated VMAT treatment plan program can create a VMAT plan of cervix cancer with high efficiency and good quality.

Image registration of a three-dimensional dynamic phantom in four-dimensional cone-beam computed tomography and four-dimensional computed tomography / 中华放射肿瘤学杂志

Objective To evaluate the image quality and registration accuracy of a three?dimensional ( 3D ) dynamic phantom in four?dimensional computed tomography ( 4DCT ) and four?dimensional cone?beam computed tomography ( 4DCBCT) . Methods The Computerized Imaging Reference Systems Dynamic Thorax Phantom Model 008A was scanned to get 4DCT and 4DCBCT images. Two balls with different diameters ( ?= 1 cm and ?= 2 cm) were used to simulate tumors with different sizes. The motion mode of the balls was 3D sinusoidal motion at 0?25 Hz ( the amplitudes along the x, y, and z axes were ±1?0 cm, ±0?4 cm, and ±0?2 cm, respectively). Gross target volumes (GTVs) from 10?phase bins, internal gross target volumes (IGTV), and target volumes on maximum intensity projection (MIP) and mean intensity projection (MeanIP) images were contoured and calculated. Target volumes on 4DCT or 4DCBCT images were compared with the static and dynamic volumes of the balls ( VS and VD ) . The matching index ( MI) of target volumes between the 4DCT and 4DCBCT images was analyzed after rigid image registration. Results The GTV in each phase of the image was larger than VS . The difference between the average GTV derived from 10 phases of 4DCT or 4DCBCT images and Vs of the small ball was larger than that of the large ball ( 35?03% vs. 22?66%;32?62% vs. 17?00%) . All the IGTVs and target volumes on MIP images were slightly larger than VD , but target volumes on MeanIP images were smaller than VD . The average MI of 10?phase bins of the small ball was smaller than that of the large ball ( 66?76% vs. 82?21%) . Moreover, MIs of IGTV,MIP, and MeanIP of the small ball were also smaller than those of the large ball ( 77?39% vs. 90?29%;75?90% vs. 89?28%;74?47% vs. 82?74%) . Conclusions In the case of a relatively small tumor volume and a relatively large motion amplitude, 4DCT and 4DCBCT should be used with caution for comparison of image registration.

Quality control of linac in daily volumetric-modulated arc therapy / 中华放射肿瘤学杂志

Objective To verify the daily delivery accuracy of volumetric-modulated arc therapy (VMAT) and achieve the process quality control (PQC) of linac using statistical process control (SPC)technology.Methods The log files of all treatments were taken out from the linac system.An in-house software which created by Matlab 7.14 was used to analyze the daily parameters accuracy and the mechanism and dose delivery accuracy of the linac for each VMAT,and an daily evaluation report was automatically created for the linac.The stability of the linac and the deviation of the delivery accuracy for various cancer sites were also analyzed.To achieve the process quality control of hnac using SPC technology,the control limit of each parameter was calculated by Johnson alternation and the single value control charts were drawn.Results 76 patients mainly with nasopharyngeal carcinoma,cervical carcinoma,rectal cancer and laryngeal cancer,got the treatment daily with VMAT technology,and a total of 2 446 arcs were delivered by the linac in continuous 16 days.The gantry angle error,y and x collimator position error,MLC leaf position error and dose delivery error were 0.49°,0.09 mm,0.38 mm,0.31 mm,0.05 MU,respectively.Compare to the nasopharynx,uteri,rectal and larynx cancer,it can be seen that the variation factors of dose delivery and gantry angle errors for various cancer sites were higher,which was 8.10％ and 4.54％,respectively.Through the process quality control of the linac,it was found that all the parameters were in control.While some abnormal points arose (the error was greater than UCL),and the ratio of the gantry angle which was out of control (0.45％) was the highest in all parameters.Conclusions linac delivery accuracy could be monitored and verified during the whole VMAT treatment for each patient,and the daily running condition of linac could be monitored.Through the introduction of SPC technology and the control charts,the process quality control of linac in VMAT could be achieved.It is a financial and valid method for the daily quality assurance of linac.

Investigation of CT numbers correction of kilo-voltage cone-beam CT images for accurate dose calculation / 中华放射肿瘤学杂志

Objective To study CT numbers correction of kilo?voltage cone?beam CT (KV?CBCT) images for dose calculation. Method Aligning the CBCT images with plan CT images, then obtain the background scatter by subtracting CT images from CBCT images. The background scatter is then processed by low?pass filter. The final CBCT images are acquired by subtracting the background scatter from the raw CBCT. KV?CBCT images of Catphan600 phantom and four patients with pelvic tumors were obtained with the linac?integrated CBCT system. The CBCT images were modified to correct the CT numbers. Finally, compare HU numbers between corrected CBCT and planning CT by paired T test. Evaluate the image quality and accuracy of dose calculation of the modified CBCT images. Results The proposed method reduces the artifacts of CBCT images significantly. The differences of CT numbers were 232 HU, 89 HU, 29 HU and 66 HU for air, fat, muscle and femoral head between CT and CBCT respectively (P= 0?? 39,0?? 66,0?? 59,1).The differences of CT numbers between CT and CBCT was reduced to within 5 HU. And the error of dose calculation with corrected CBCT images was within 2%. Conclusions The CT numbers of corrected CBCT are similar with plan CT images and dose calculations based on the modified CBCT show good agreement with plan CT.

Meta-Mesh: metagenomic data analysis system / 生物工程学报

With the current accumulation of metagenome data, it is possible to build an integrated platform for processing of rigorously selected metagenomic samples (also referred as "metagenomic communities" here) of interests. Any metagenomic samples could then be searched against this database to find the most similar sample(s). However, on one hand, current databases with a large number of metagenomic samples mostly serve as data repositories but not well annotated database, and only offer few functions for analysis. On the other hand, the few available methods to measure the similarity of metagenomic data could only compare a few pre-defined set of metagenome. It has long been intriguing scientists to effectively calculate similarities between microbial communities in a large repository, to examine how similar these samples are and to find the correlation of the meta-information of these samples. In this work we propose a novel system, Meta-Mesh, which includes a metagenomic database and its companion analysis platform that could systematically and efficiently analyze, compare and search similar metagenomic samples. In the database part, we have collected more than 7 000 high quality and well annotated metagenomic samples from the public domain and in-house facilities. The analysis platform supplies a list of online tools which could accept metagenomic samples, build taxonomical annotations, compare sample in multiple angle, and then search for similar samples against its database by a fast indexing strategy and scoring function. We also used case studies of "database search for identification" and "samples clustering based on similarity matrix" using human-associated habitat samples to demonstrate the performance of Meta-Mesh in metagenomic analysis. Therefore, Meta-Mesh would serve as a database and data analysis system to quickly parse and identify similar

Analysis of drug resistance tendency of Acinetobacter baumannii in Meizhou area during 2008-2012 / 国际检验医学杂志

Objective To analyze the detection rate and drug resistance tendency of Acinetobacter (A .) baumannii in Meizhou area during 2008-2012 in order to provide the guidance for clinicians′medication .Methods The detection rate and drug resistant rate of A .baumanii in the clinical specimens submitted from 5 hospitals in Meizhou during 2008 -2012 were retrospectively ana-lyzed .The antimicrobial susceptibility test was performed by the disk diffusion method .The WHONET 5 .4 and SPSS18 .0 soft-wares were adopted to analyze the data .Results The detection rates of A .baumanii in these five years were 12 .91% ,15 .40% , 11 .94% ,13 .59% and 14 .00% respectively .In the sources of strains ,sputum had the highest distribution rate of 68 .99% (1 713/2 483) ,in the distribution of departments ,ICU had the highest distribution rate of 33 .91% (842/2 483) .The resistance rate of A . baumannii to cefoperazone/shubatam ,meropenem and imipenem were below 30% in the five years ,but showed the upward tenden-cy .The 5-year total drug resistance rates of A .baumanii to 18 kinds of antibacterial drugs were statistically different between ICU and non-ICU department (P<0 .05) ,the drug resistant rate of isolates from ICU was higher than that from the non-ICU depart-ments .The isolation rate of multi-drug resistant strains of A .baumanii was fluctuated in about 50% during these five years except the lower isolation rate in 2008 ,the isolation rate of pan-drug resistant A .baumanii and carbapenem resistance A .baumanii showed the upward tendency .Conclusion The drug resistance rate of A .baumanii is gradually increased .The drug resistance monitoring of A .baumanii in ICU should be strengthened .Antimicrobial agents should be reasonably used for maximizing to retard the emergence of drug resistant strains .

Resistance mechanism and molecular epidemiological characteristics of isolated clinically carbapenem-resistant Acinetobacter baumannii in Meizhou, China / 中国人兽共患病学报

In order to survey antibiotic resistance of clinical isolates carbapenem-resistant A cinetobacter baumannii in Meizhou and to investigate resistance mechanism and molecular epidemiological characteristics ,a total of 210 non-duplicated clinical isolates of carbapenem-resistant Acinetobacter baumannii from January 2012 to December 2012 were collected .The K-B disk diffusion method was applied for the drug-susceptibility test ,a modified Hodge test was used for the screening of carbapen-emase ,PCR was used to amplify carbapenemase genes (including IMP ,VIM ,OXA-23 ,OXA-24 ,OXA-51 and OXA-58) ,and the positive products were sequenced .Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) was used for DNA typing and test of homology .Our results on the percentage of strains resistant for antibiotics tested were higher than 60% except for polymyxin B was 0 .48% .There were 163 positive strains by the modified Hodge test ,accounting for 77 .62% .OXA-51 gene was identified in 198 strains (94 .29% ) ,OXA-23 in 165 strains (78 .57% ) ,and VIM in 9 strains (4 .29% ) ,OXA-24 ,OXA-58 and IMP gene was not identified by PCR amplification .Seven genomic types were included in the 210 carbapenem-resistant Acinetobacter baumannii .The major prevalence types were Type A (97 strains) ,Type B (44 strains) and Type H (25 strains) . In conclusion ,multiple drug resistance of clinically isolated carbapenem-resistant A cinetobacter baumannii is a serious problem in Meizhou .Production of OXA-51 ,OXA-23 and IMP carbapenemases is an important mechanism of resistance to carbapenem antibiotics ,and there is prevalence of the same clones in these carbapenem-resistant strains .

Monte Carlo simulation and validation of the multi-leaf collimator of Varian 23EX accelerator / 南方医科大学学报

<p><b>OBJECTIVE</b>To simulate the multi-leaf collimator of Varian linear accelerator using Monte Carlo method.</p><p><b>METHODS</b>The multi-leaf collimator model was established using the DYNVMLC module of BEAMnrc and validated by comparison of Monte Carlo simulation and actual measurement results.</p><p><b>RESULTS</b>The simulation results were well consistent with the actual measurement results with a bias of less than 3%.</p><p><b>CONCLUSION</b>The multi-leaf collimator of Varian linear accelerator can be successfully modeled using Monte Carlo method for analysis of the impact of the geometric properties of the multi-leaf collimator on the dose distribution.</p>

Measurement and calculation of X-ray small fields' data for Varian accelerator / 中华放射肿瘤学杂志

Objective The beam data is compared with those obtained from Monte Carlo (MC)simulation and measurement to investigate their feasibility and reliability for X-ray small fields.MethodsThe beam data,including the total scatter factor (Scp),percentage depth dose (PDD) was acquired byneasurement and calculation with the field size ranging from 0.5 cm × 0.5 cm to 10 cm x 10 cm.The resultswere compared and analyzed.Results All the data is most consistent for the fields size of ≥3.5 cmx 3.5cm,but they are obvious different for the fields size of ≤ 3.0 cm × 3.0 cm.The measurements seem toreliable using the chambers of CC04 and CC13 for the fields size of ≥2.0 cm x 2.0 cm.Conclusions It isdemonstrated that the accurate measurements and calculations of Scp and PDD can be obtained for the fieldssize of ≥2.0 cm ×2.0 cm,but they needed morc rcscarchcs for thc smaller fields.