C2 pedicle screw insertion assisted by mobilization of the vertebral artery in cases with high-riding vertebral artery / 中华外科杂志

Objective: To examine the feasibility, safety, and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with high-riding vertebral artery (HRVA). Methods: The clinical data of 12 patients with basilar invagination and atlantoaxial dislocation underwent atlantoaxial reduction and fixation in the Department of Neurosurgery, the First Affiliated Hospital of University of Science and Technology of China between January 2020 and November 2021 were retrospectively analyzed. All patients had high-riding vertebral artery on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 10 females aged (48.0±12.8) years (range: 17 to 67 years). After correction of vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including the anterior atlantodental interval (ADI), the distance of the odontoid tip above the Chamberlain line, the clivus-canal angle, were collected and compared by paired t-test. Results: Mobilization of the high-riding vertebral artery was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were achieved in all 12 patients. All patients achieved bone fusion 6 months after surgery. No looseness and shift in internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative ADI decreased from (6.1±1.9) mm to (2.0±1.2) mm (t=6.73, P<0.01), the distance of the odontoid tip above the Chamberlain line decreased from (10.4±2.5) mm to (5.5±2.3) mm (t=7.12, P<0.01), the clivus-canal angle increased from (123.4±11.1) ° to (134.7±9.6) ° (t=2.50, P=0.032), the JOA score increased from 13.3±2.1 to 15.6±1.2 (t=6.99, P<0.01). Conclusion: The C2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.

Clinicopathological and molecular features of metaplastic thymoma / 中华病理学杂志

Objective: To investigate the clinicopathological features, and molecular genetic alterations of metaplastic thymoma (MT). Methods: A total of ten MT cases, diagnosed from 2011 to 2021, were selected from the Department of Pathology of Jinling Hospital, Nanjing University Medical School, Nanjing, China for clinicopathological and immunohistochemical (IHC) examination and clinical follow-up. Fluorescence in situ hybridization (FISH), next-generation sequencing (NGS), and YAP1 C-terminus (YAP1-CT) IHC were performed to detect YAP1::MAML2 fusions. Results: There were four males and six females, ranging in age from 29 to 60 years (mean 50 years, median 54 years). Microscopically, all tumors showed a typical biphasic morphology consisting of epithelial components and gradually or abruptly transitioning spindle cell components. The two components were present in varying proportions in different cases. Immunophenotypically, the epithelial cells were diffusely positive for CKpan, CK5/6 and p63. The spindle cells were diffusely positive for vimentin and focally positive for EMA. TdT was negative in the background lymphocytes. Ki-67 proliferation index was less than 5%. YAP1 and MAML2 break-apart FISH analyses showed that all ten cases had narrow split signals with a distance of nearly 2 signal diameters and may be considered false-negative. Using YAP1::MAML2 fusion FISH assays, abnormal fusion signals were observed in all the ten cases. NGS demonstrated YAP1::MAML2 fusions in all eight cases with adequate nucleic acids; in two cases the fusions were detected by DNA sequencing and in eight cases by RNA sequencing. All ten cases of MT demonstrated loss of YAP1 C-terminal expression in epithelioid cells. Conclusions: MT is a rare and low-grade thymic tumor characterized by a biphasic pattern and YAP1::MAML2 fusions. Break-apart FISH assays may sometimes show false-negative results due to the proximity of YAP1 and MAML2, while YAP1 C-terminal IHC is a highly sensitive and specific marker for MT. Loss of YAP1 C-terminal expression can also be used to screen YAP1::MAML2 fusions for possible MT cases.

Prevalence of antiretroviral drug resistance in treatment-naive injecting drug users infected with HIV-1 in Guangzhou, 2008-2015 / 中华流行病学杂志

Objective: To understand the prevalence of drug resistance in treatment-naive injecting drug users (IDUs) infected with HIV-1 in Guangzhou. Methods: HIV-1 RNA were extracted from the serum specimens of the newly confirmed HIV-1 positive IDUs living in Guangzhou, being infected through injecting drug use and receiving no antiretroviral therapy at the time of confirmation during 2008-2015. Full sequence of pol protease (PR) gene and partial sequence of reverse transcriptase (RT) gene were amplified by nested reverse transcription polymerase chain reaction (nested-PCR) and sequenced. After that, data were submitted to the HIV resistance database of Stanford University for drug resistance analysis. Results: Among the 518 HIV-1 infected IDUs, HIV-1pol gene segments were successfully obtained from the serum samples of 407 HIV-1 infected IDUs (78.57%) aged 18-64 (37.44±8.14) years. Among them, males accounted for 89.68% (365/407), those of Han ethnic group accounted for 89.93% (366/407), the unmarried accounted for 55.28% (225/407), and those with education level of junior high school or below accounted for 83.78% (341/407). The distribution of subtypes was predominated by CRF07_BC (47.18%, 192/407), followed by CRF01_AE (23.83%, 97/407), CRF08_BC (22.85%, 93/407), and other subtypes (6.14%, 25/407). The overall prevalence of drug resistance was 3.44% (14/407). The prevalence of drug resistance to protease inhibitors, nucleoside reverse transcriptase inhibitors and non-nucleoside reverse transcriptase inhibitors were 1.47%(6/407), 0.25% (1/407) and 1.72% (7/407) respectively. The mutation rate was 12.29% (50/407). No major drug resistance mutation was detected in protease and nucleoside reverse transcriptase regions. Higher rate of V179E mutation in the non-nucleoside reverse transcriptase region was detected in other subtypes and subtype CRF07_BC. Mutation seemed to have occurred in all 8 cases of subtype CRF55_01B in other subtypes. The highest mutation rate of E138A was detected in subtype CRF08_BC (3.23%). Two cases were resistant to all four drugs of NNRTIs. Conclusions: The prevalence of drug resistance in treatment-naive HIV-1 positive IDUs remained at a relatively low level during 2008-2015, in Guangzhou. Most infections were sensitive to existing antiviral drugs. However, drug resistance surveillance in IDUs infected with HIV should be strengthened to prevent the prevalence of multi-drug resistance and cross drug resistance.