[Evaluation on applicationof virtual reality technology in dental implant process training].

Objective: To explore the application effect and evaluation of virtual reality technology in oral implant therapy training. Methods: In November 2018, one adult patient (female, 36 years old) with missing right mandibular first molar was treated in the Department of Implantology, School and Hospital of Stomatology, Fujian Medical University. The three-dimensional virtual models of mandible and implant surgery tools were established, and the virtual reality software (Unity 3D 5.5.1) was imported. Combined with the virtual reality head mounted display, a virtual reality training system simulating the dental implant treatment process was independently developed. Ten refresher doctors and 20 graduate students in Department of Implantology, School and Hospital of Stomatology, Fujian Medical University from September 2018 to December 2019 were recruited as the experimental objects (no clinical experience was found). According to the level and seniority of doctors, they were randomly divided into virtual training group and conventional training control group, which made the two groups comparable, with 15 in each group. Subjective scores (including anatomical structure, surgical field of vision, cavity preparation, implant placement and process mastery) were given after the corresponding training in the two groups, and the virtual reality training system was used to test. The mesial and distal direction, buccolingual direction, depth and angle deviation of implants before and after the training were analyzed, and the differences between the two groups were compared. Results: The subjective scores of five dimensions in the virtual training group were significantly higher than those in the conventional training control group (P<0.05). In the virtual training group, the mesial and distal, buccolingual, depth and angle deviation of implants were (0.73±0.33), (0.78±0.41), (0.61±0.32) mm and 6.66°±3.87°. All of them were significantly lower than those in the control group [(0.85±0.32), (1.12±0.38), (0.89±0.24) mm and 9.68°±3.74°] (P<0.05). Conclusions: The self-developed virtual reality system of oral implant has good application effect, good operability and predictability. It can be effectively carried out in implant education and training, and it can strengthen skills of doctors, and is conducive to the practical operation.

Placental NRP1 and VEGF expression in pre-eclamptic women and in a homocysteine-treated mouse model of pre-eclampsia.

OBJECTIVES: To investigate the expression levels of neuropilin 1 (NRP1) and vascular endothelial growth factor (VEGF) in the placentas of women with pre-eclampsia (PE), determine whether homocysteine (Hcy) contributes to the development of PE in mice, and detect alterations in placental NRP1 and VEGF in Hcy-treated mice. STUDY DESIGN: Placental tissue samples were obtained from 16 patients with and without PE. Using reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, the expression levels of NRP1 and VEGF in PE and control placental tissues were examined. Immunohistochemical (IHC) assay was used to detect the localization of NRP1 and VEGF proteins. Pregnant mice were treated with DL-Hcy on embryonic day 7.5. The symptoms of the treated mice were examined. The expression levels of Ddah1, Ddah2, eNos, Cbs and Cse were determined by quantitative RT-PCR to study the possible mechanism of hyperhomocysteinemia (HHcy). Nrp1 and Vegf expression levels in the placentas of treated mice were measured by quantitative RT-PCR, western blot analysis and IHC. RESULTS: NRP1 and VEGF were expressed at lower levels in women with PE compared with control women. The immunoreactivity of NRP1 was detected in villous trophoblast cells and villous capillary endothelial cells (ECs). Immunoreactive VEGF was observed mainly in vascular ECs within the villi. The pregnant mice treated with DL-Hcy showed PE-like symptoms such as higher systolic blood pressure and proteinuria in late pregnancy. Compared with the control mice, Ddah1, Ddah2 and eNos mRNA were expressed at lower levels, and Cbs and Cse mRNA were expressed at significantly higher levels in the placentas of the Hcy-treated group. Expression levels of Nrp1 and Vegf in mice placentas were decreased in the Hcy-treated group. CONCLUSIONS: DL-Hcy can induce PE-like symptoms in mice. Both placental NRP1 and VEGF were expressed at lower levels in women with PE and Hcy-treated mice, which may contribute to endothelial damage.

[Management of recurrent hemorrhage in portal hypertension].

123 cases of recurrent hemorrhage were studied. It was found that the rebleeding rate differed with different original operations. Those with unsatisfactory portal decompression or persistence of varices were prone to rebleeding. Rebleeding within one year occurred in 47.96%, and in late stage in 52.04%. Early postoperative rebleeding should be treated conservatively with intensive circulatory resuscitation. Repeated rebleeding occurred in 89% of the patients, reoperation should be carried out with definite indications. Emergency surgery was usually not recommended. On the operation, portal vein thrombosis was found in 58.8% of the patients, and dilatation of the superior mesenteric vein in 82.9%. Of the fifty six rebleeding cases treated surgically, 21.4% died of further bleeding in 5 years compared with 50.7% treated conservatively. Rebleeding occurred in 62.5% of disconnection cases and in 31.2% of shunt cases. The authors performed mesocaval side-to-side anastomosis in those with enlarged superior mesenteric vein, and restricted portocaval shunt in those without portal thrombosis. Rebleeding patients with regional portal hypertension were better treated with devascularization.