The structure and working principle of the multi-leaf collimator(MLC)optical system of Elekta linear accelerator were introduced.The causes for the faults of the MLC optical system were analyzed,and the fault repair and maintenance of the MLC optical system were summarized.References were provided for medical engineers to repair and maintain the MLC optical system.[Chinese Medical Equipment Journal,2024,45(1):76-83]

Objective To investigate the immediate brain effect of acupuncture at Fengchi using amplitude of low-frequency fluctuation(ALFF)and functional connectivity by the resting-state functional magnetic resonance imaging(rs-fMRI)in patients with posterior circulation ischemia vertigo(PCIV).Methods Twenty patients with PCIV were enrolled.The dizziness handicap inventory(DHI)was used to evaluate the severity of vertigo.The patients were randomly divided into acupuncture group and sham acupoint acupuncture group.Rs-fMRI scan was performed before and after acupuncture.MATLAB-based DPABI 6.1 software was used to analyze rs-fMRI data.Correlation analysis was used between the altered ALFF values and DHI scores.The regions of altered ALFF were taken as seeds to analyze functional connectivity.Results Compared with the sham acupoint acupuncture group,the increased ALFF values were mainly located on the left precuneus,left superior frontal gyrus and left caudate nucleus after acupuncture in the acupuncture group;the decreased ALFF values were mainly located on the left cerebellum and right inferior occipital gyrus.The ALFF value of the left superior frontal gyrus was negatively correlated with the DHI score(P=0.04).The increased functional connectivity was mainly found between left precuneus and the right middle frontal gyrus,the right superior frontal gyrus,the decreased functional connectivity was mainly found between left precuneus and the bilateral paracentral lobule and right cerebellum.Conclusion The ALFF value and functional connectivity are different before and after acupuncture,indicating that the vestibular network,visual and motor brain regions functional activities are changed after needling at Fengchi,which may be the brain functional basis of Fengchi for vertigo in PCIV.

Objective:To compare and evaluate recurrence patterns after robotic-assisted gastrectomy (RAG) versus laparoscopic-assisted gastrectomy (LAG).Methods:This was a retrospective cohort study of 2915 consecutive patients with gastric adenocarcinoma confirmed by postoperative histology as T1-4aN0-3M0, who had undergone minimally invasive radical gastrectomy at four large gastric cancer treatment centers (Fujian Medical University Union Hospital: 1426 patients; the First Affiliated Hospital, Nanchang University: 1108; Tianjin Medical University Cancer Institute and Hospital: 196; and First Affiliated Hospital of Xi'an Jiaotong University: 185 cases) between 1 January 2015 and 30 June 2019. 930 patients had undergone RAG (RAG group) and 1985 had undergone LAG (LAG group). We assessed the following characteristics: age, sex, body mass index, American Society of Anesthesiologists score, comorbidities, tumor size, extent of surgery, extent of lymph node dissection, pT, pN, year of surgery, and adjuvant chemotherapy, after propensity score matching (1:1). There were no significant differences in baseline clinical characteristics between the two groups formed by propensity score matching (837 in each group) (all P>0.05). The 3-year recurrence-free survival (RFS), recurrence pattern, and conditional RFS were compared. Results:We detected no significant differences in the overall recurrence rate at 3 years (128/837 [15.3%] vs. 141/837 [16.8%], P=0.387) or time to recurrence (15.7±8.1 months vs. 16.4±8.4 months, P=0.449) between the RAG and LAG groups. Peritoneal recurrence was the most common type of recurrence in both groups (55 [6.6%] vs. 69 [8.2%], P=0.524). The difference in 3-year RFS between the RAG and LAG groups was not statistically significant (83.2% vs. 82.5%, P=0.781). We found that age > 60 years, total gastrectomy, and worse pT stage and pN stage were independent risk factors for recurrence in the study patients (all P<0.05), whereas the surgical procedure (RAG or LAG) was not an independent risk factor for RFS ( P=0.242). The 3-year conditional RFS at various time points was comparable between the two groups (1 year postoperatively: 84.6% vs. 84.7%, P=0.793; 3 years postoperatively: 91.5% vs. 94.9%, P=0.647). Conclusions:In this multicenter study of patients with locally resectable gastric cancer, we demonstrated that RAG performed by surgeons at large gastric cancer centers is not inferior to LAG in 3-year recurrence rate or recurrence patterns.

Objective:To compare and evaluate recurrence patterns after robotic-assisted gastrectomy (RAG) versus laparoscopic-assisted gastrectomy (LAG).Methods:This was a retrospective cohort study of 2915 consecutive patients with gastric adenocarcinoma confirmed by postoperative histology as T1-4aN0-3M0, who had undergone minimally invasive radical gastrectomy at four large gastric cancer treatment centers (Fujian Medical University Union Hospital: 1426 patients; the First Affiliated Hospital, Nanchang University: 1108; Tianjin Medical University Cancer Institute and Hospital: 196; and First Affiliated Hospital of Xi'an Jiaotong University: 185 cases) between 1 January 2015 and 30 June 2019. 930 patients had undergone RAG (RAG group) and 1985 had undergone LAG (LAG group). We assessed the following characteristics: age, sex, body mass index, American Society of Anesthesiologists score, comorbidities, tumor size, extent of surgery, extent of lymph node dissection, pT, pN, year of surgery, and adjuvant chemotherapy, after propensity score matching (1:1). There were no significant differences in baseline clinical characteristics between the two groups formed by propensity score matching (837 in each group) (all P>0.05). The 3-year recurrence-free survival (RFS), recurrence pattern, and conditional RFS were compared. Results:We detected no significant differences in the overall recurrence rate at 3 years (128/837 [15.3%] vs. 141/837 [16.8%], P=0.387) or time to recurrence (15.7±8.1 months vs. 16.4±8.4 months, P=0.449) between the RAG and LAG groups. Peritoneal recurrence was the most common type of recurrence in both groups (55 [6.6%] vs. 69 [8.2%], P=0.524). The difference in 3-year RFS between the RAG and LAG groups was not statistically significant (83.2% vs. 82.5%, P=0.781). We found that age > 60 years, total gastrectomy, and worse pT stage and pN stage were independent risk factors for recurrence in the study patients (all P<0.05), whereas the surgical procedure (RAG or LAG) was not an independent risk factor for RFS ( P=0.242). The 3-year conditional RFS at various time points was comparable between the two groups (1 year postoperatively: 84.6% vs. 84.7%, P=0.793; 3 years postoperatively: 91.5% vs. 94.9%, P=0.647). Conclusions:In this multicenter study of patients with locally resectable gastric cancer, we demonstrated that RAG performed by surgeons at large gastric cancer centers is not inferior to LAG in 3-year recurrence rate or recurrence patterns.

Objective: To investigate the clinical efficacy of liver transplantation in the treatment of acute liver in children with NBAS gene deficiency disease and their outcome. Methods: This retrospective study enrolled children with NBAS gene deficiency who were admitted to the Children's Hospital of Fudan University for liver transplantation from January 2013 to June 2022. The clinical data were collected and analyzed. Medical literature published before June 2022 was searched with the keywords of "NBAS" "neuroblastoma amplified sequence recurrent" "acute liver failure" "SOPH syndrome" "short stature with optic nerve atrophy" "Pelger-Huët anomaly" in PubMed, China National Knowledge Infrastructure and Wanfang database. Results: Liver transplantation was performed in 3 patients (2 males and 1 female) with NBAS deficiency. All patients presented with fever-triggered recurrent acute liver failure. The genetic detection found compound heterozygous NBAS gene pathogenic variants in them. The total episodes of acute liver failure before liver transplantation were 11, 2, and 4 respectively, and the age at liver transplantation was 3.5, 2.3, and 2.0 years respectively. During liver transplantation, patient 1 was in the convalescent phase of acute liver failure, patient 2 was in the acute phase, presenting with hepatic encephalopathy (grade V) and respiratory failure, and patient 3 was considered to be in the acute phase. After liver transplantation, patient 1 recovered normal liver function within 1 month and had no liver transplantation-related complications. Patient 2 had secondary epilepsy, intellectual disability, movement disorder, and transiently elevated transaminases. Patient 3 died of severe infection within 1 month. There was no literature in Chinese, 6 in English, 8 NBAS-deficient patients who were treated with liver transplantation. Total 11 patients presented with fever-triggered recurrent acute liver failure. Their age at liver transplantation ranged from 0.9 to 5.0 years. Postoperative complications occurred in 3 patients. Until the last visit, they were followed up for 0.7 to 14.0 years. Total 2 patients died and the 9 surviving patients did not develop acute liver failure. Conclusions: Liver transplantation is effective for the treatment of acute liver failure associated with NBAS gene disease. However, postoperative complications of liver transplantation may occur. The timing of liver transplantation still needs further research.
Child ; Male ; Humans ; Female ; Infant ; Child, Preschool ; Retrospective Studies ; Neoplasm Proteins/genetics* ; Optic Atrophy/genetics* ; Pelger-Huet Anomaly/genetics* ; Liver Failure, Acute/complications*

Objective:To explore the application value of chromosome karyotype analysis, chromosomal microarray analysis (CMA) and whole exome sequencing (WES) in prenatal diagnosis of isolated corpus callosum abnormality (CCA) fetus.Methods:Fetuses diagnosed with isolated CCA by ultrasound and MRI and receiving invasive prenatal diagnosis in Guangzhou Women and Children′s Medical Center and Qingyuan People′s Hospital from January 2010 to April 2021 were selected. Karyotype analysis and/or CMA [or copy number variation sequencing (CNV-seq)] were performed on all fetal samples, and WES was performed on fetal samples and their parents whose karyotype analysis and/or CMA (or CNV-seq) results were not abnormal.Results:Among 65 fetuses with isolated CCA, 38 cases underwent karyotype analysis, and 3 cases were detected with abnormal karyotypes, with a detection rate of 8% (3/38). A total of 49 fetuses with isolated CCA underwent CMA (or CNV-seq) detection, and 6 cases of pathogenic CNV were detected, the detection rate was 12% (6/49). Among them, the karyotype analysis results were abnormal, and the detection rate of further CMA detection was 1/1. The karyotype results were normal, and the detection rate of further CMA (or CNV-seq) detection was 14% (3/21). The detection rate of CMA as the first-line detection technique was 7% (2/27). A total of 25 fetuses with isolated CCA with negative results of karyotyping and/or CMA were tested by WES, and 9 cases (36%, 9/25) were detected with pathogenic genes. The gradient genetic diagnosis of chromosomal karyotyping, CMA and WES resulted in a definite genetic diagnosis of 26% (17/65) of isolated CCA fetuses.Conclusions:Prenatal genetic diagnosis of isolated CCA fetuses is of great clinical significance. The detection rate of CMA is higher than that of traditional karyotyping. CMA detection could be used as a first-line detection technique for fetuses with isolated CCA. WES could increase the pathogenicity detection rate of fetuses with isolated CCA when karyotype analysis and/or CMA test results are negative.

Objective:To analyze the viral nucleic acid and cytokines in 12 children with 2019-nCoV infection.Methods:Clinical and laboratory data of the children diagnosed with 2019-nCoV infection in Guangzhou Women and Children′s Medical Center from January to April 2020 were retrospectively analyzed. Throat and anal swabs were collected on alternate days for the detection of 2019-nCoV nucleic acid by fluorescence quantitative PCR. Flow cytometry was used to detect serum cytokines including IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-17F, IL-22, TNF-α and TNF-β during the early (both throat and anal swab tests were positive), the intermediate (throat swab test was negative, while anal swab test remained positive), and the convalescence (both throat and anal swab tests were negative) stages of infection.Results:A total of 12 children were enrolled in this study. The male-to-female ratio was 5∶1. The average age was (7.0±4.3) years. There were two asymptomatic, five mild and five common cases. No severe or critical cases were involved. Initially, throat and anal swab nucleic acid tests were simultaneously positive in nine children newly diagnosed in our hospital and the median time of viral shedding in throat swab was longer than that in throat swab [32 (4.5, 45.0) d vs 3 (2, 9) d, Z=11.0, P=0.010]. The median difference of viral shedding time between anal swab and pharyngeal swab was 25.5 (1.5, 42.8) d. The overall levels of serum cytokines IL-17A, IL -4 and IL-5 in different stages of the disease (early, intermediate and convalescence stage) were statistically different ( Z or F, P values were 8.33, 0.016; 5.36, 0.010 and 6.56, 0.004, respectively), and a significant increase was observed in the intermediate stage of infection. IL-17F, IL-2 and IL-22 were all increased during the infection, but there was no significant statistical difference among the three stages ( P>0.05). Conclusions:It was noted that intestinal viral shedding needed a longer time. Although the infectivity has not been determined, higher requirements have been put forward for disease prevention and control. Cytokines secreted by Th2 and Th17 cells were involved in the immune response in children with non-severe 2019-nCoV infection. Monitoring viral shedding and cytokine changes in pediatric patients would be conducive to disease assessment.

Objective To investigate the effect of long-term high-fat diet on cognitive function and hippocampus neurons ultrastructure in obese rats.Methods Forty SD rats were randomly assigned to a high fat diet (HFD) group and a common diet (CD) group.Meanwhile,HFD-induced obese rat model were established.The spatial learning and memory were measured by the Morris water maze,and the neurons ultrastructural changes in rat hippocampus CA1 region at the corresponding period were observed by transmission electron microscopy.Results The average weight of rats was 25％,28％,and 22％ higher in the HFD group than in the CD group at the 12,16,and 20 weeks,respectively;the Lee's indexes were 6％,4％,and 8％ higher;the average swimming latency were 52％,44％,and 40％ longer;the average swimming distance were 85％,45％,and 51％ longer;the average swimming speed were 57％,34％,and 18％ higher;the duration of staying in the target quadrant were 32％,54％,and 63％ shorter;and the average times of crossing the plate form were 30％,34％,and 34％ shorter,respectively (all P ＜0.001).In comparison of ultrastructure in hippocampus CA1 region of rats at corresponding time points,the amounts of degenerated and necrosis neurons,of the deformed and vacuolar mitochondria,and of the less rough endoplasmic reticulum were significantly more at 12,16,and 20 weeks in the HFD group than in the CD group.Conclusions Long-term HFD-induced obesity damages the structure of neurons in the hippocampus,impairs spatial learning and memory function,and accelerates cognitive aging in rats.

OBJECTIVETo assess the effect of long-term high-fat diet on the expressions of insulin receptor substrates in the hippocampus and spatial learning and memory ability of obese rats.

METHODSA total of 100 4-week-old male SD rats were randomly divided into two groups and fed with common diet (CD group, n=40) or high-fat diet (HFD group, n=60) for 16 weeks. At 4, 8, 12, 16 and 20 weeks, 8 rats were randomly selected from each group for testing their spatial learning and memory function using Morris water maze. After the tests, the rats were sacrificed for measurement of the metabolic parameters and detection of the expressions of insulin receptor substrate-1 (IRS-1) and IRS-2 mRNAs in the CA1 region of the hippocampus.

RESULTSCompared with those in CD group, the rats in HFD group showed a prolonged escape latency, longer swimming distance, faster average swimming speed, and shorter stay in the platformat 12 weeks. In HFD group, the serum levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol, and fasting insulin were all significantly increased (P<0.05) and the level of high-density lipoprotein cholesterol decreased (P<0.01) in comparison with those in CD group at each of the time points. No significant difference was found in fast glucose levels between the two groups (P>0.05), but the expressions of IRS-1 and IRS-2 mRNAs were significantly decreased in HFD group at 12 weeks (P<0.05).

CONCLUSIONIn obese rats, long-term feeding with high-fat diet leads to insulin resistance, which interferes with hippocampal expression of insulin receptor substrates and insulin metabolism to cause impairment of the cognitive function and accelerate cognitive deterioration.

Madelung deformity is a rare deformity of forearm and wrist caused by growth disorders of distal radius ulnar and palmar epiphyseal. Current studies showed that its incidence mainly associated with trauma, epiphyseal developmental abnormalities, nutritional disorders and genetic deletion or mutation. The early clinical presentation is not typical, in middle and late time, wrist deformity and weak can appear. Plain film considered as the main means of diagnosis is often lack of early diagnosis significance. Although wrist joint magnetic resonance imaging showing early soft tissue and skeletal abnormalities were used for the early diagnosis of the disease, current domestic study in magnetic resonance imaging of this deformity is less. According to the size of the distal ulnar inclination angle and palm angle, this deformity can be divided into different types. The patients with severe deformity and symptoms usually need surgical intervention including ulna revision and osteotomy of the distal radius at present. Although the two operation can achieve good clinical results, the surgical trauma, infection and postoperative risk of joint activities are more.