Positive reverse transcription-polymerase chain reaction assay results in patients recovered from COVID-19: Report of two cases.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has spread around the globe. On February 28, 2020, the World Health Organization adjusted the risk of spread and impact of COVID-19 to "very high" at the global level. Studies have mainly focused on the etiology, epidemiology, and treatment of COVID-19 to limit further spread and the negative impact of the disease, while less attention has been devoted to the follow-up and reexamination of patients who recovered from COVID-19 or were released from quarantine. CASE SUMMARY: This study reports two cases where patients who had negative reverse transcription-polymerase chain reaction (RT-PCR) test results and met the criteria for discharge subsequently had positive RT-PCR test results. The clinical manifestations and computed tomography (CT) findings of these patients were examined. The conversion of RT-PCR test results in these two patients may be related to false-negative and false-positive outcomes of the test. CT images helped track improvement of pulmonary lesions. CONCLUSION: The timing of discharge of COVID-19 patients should be determined by comprehensive analysis of CT images and RT-PCR test results.

A rare and fatal respiratory disease: bronchial Dieulafoy's disease.

A 66-year-old woman had two severe episodes of massive hemoptysis without any premonitory symptoms, with approximately 400-500 ml blood each time. Bronchoscopic exam revealed a smooth and pulsatile protrusion that was approximately 8-10 mm in diameter found at the beginning of the right middle lobe bronchus in the bronchial lumen. The protrusion arose from the surface with absolutely normal mucosa. Selective bronchial arteriography showed that elongated, tortuous, and dilated branches of the bronchial artery in the region of the middle lobe bronchus. Further bronchial arterial embolization (BAE) is recommended, although the patient currently has no active bleeding. Bronchial Dieulafoy's disease (BDD) is a rare and life-threatening disease. Selective bronchial arteriography is a diagnostic tool to detect and locate abnormal arteries. There is no unified guideline or expert consensus on the treatment of BDD. Selective BAE or surgical resection is usually used as a first-line treatment to control hemoptysis. The reviews of this paper are available via the supplemental material section.

[Finite element analysis of the influence of anchorage number and location on Bankart repair strength of shoulder joint].

OBJECTIVE: To study the influence of the number and position of anchor nails on the Bankart repair by the finite element analysis. METHODS: The 3D CT data of shoulder joints including normal adult volunteers were imported into Mimics 10.0 and Geomagic 2012 software to reconstruct the related tissues, and then meshed in Hypermesh 13.0 software to give material attributes. The position and number of MPC constraints were adjusted in Abaqus 6.14 to establish finite element model of shoulder joint under 6 working conditions including A model(normal control model), B model (Bankart damage control model), C model (1 anchor), D model (2 anchors), E model (3 anchors), F model (4 anchors). The humerus external rotation and forward load were added to simulate the fear test of the shoulder joint forward instability. RESULTS: (1)Normally, the inferior glenohumeral ligament complex accompanied by the external rotation of the humerus head has a wrinkle and a significant stress concentration around its anterior and posterior bundle terminations.(2)The stress of the anterior bundle and posterior bundle of the inferior glenohumeral ligament were increased by 52.33% and 45.67% respectively after Bankart's injury.(3)In each model of anchor repair, the stress concentration was obvious at the anchor site, and the stress of anterior and posterior bundle ligaments could be reduced; there were no obvious differences between C, D models and B model(P>0.05), and there were significant differences between E, F models and B model(P<0.05). CONCLUSIONS: One or two anchors can reduce the stress of the anterior and posterior bundles of the inferior glenohumeral ligament in the repair of Bankart's injury, but when the angle of rotation is large, the stress concentration in the anchor position increases significantly, leading to the increases of the risk of failure. The application of three or four anchors can enhance the constraints on the inferior glenohumeral ligament and reduce the stress of the anchor itself through the "load sharing" effect between anchors, so as to ensure the stability of the shoulder joint and provide a mechanical environment for the early rehabilitation of patients.