Objective:To understand the positive rate of 2019 novel coronavirus (2019-nCoV) specific IgG antibody induced by Coronavirus Disease 2019 (COVID-19) inactivated vaccine in healthy population in Xizang Autonomous Region, and evaluate the immune effect of the vaccine.Methods:Serum samples were collected from COIVD-19 vaccine immunized health population without history of 2019-nCoV infection from six prefecture-level cities in Xizang Autonomous Region. The IgG antibody against 2019-nCoV were tested by chemiluminescence method. Then, the positive rate of IgG antibody was analyzed for different immunization histories and age groups.Results:A total of 22 255 participants were enrolled in this survey. After full-access (two doses of vaccine) and booster immunization, the overall positive rate of specific IgG antibody against 2019-nCoV was 96.38%. The positive rate of IgG antibody in the booster immunized population was 97.12%, which was much higher than the 88.38% in the full-access immunization population, the difference is statistically significant ( χ2=381.11, P<0.001). There was a significant differences in the positive rates of specific IgG antibodies in different age groups ( χ2=138.28, P<0.001). Especially in the younger age groups, including less than 10 years old and the 11-20 years age group, the positive rate of specific IgG antibody were 93.44% and 89.03% respectively, which were lower than those in other age groups. Except for Naqu city and the age group ≤ 10 years old, the differences in antibody positivity rates were statistically significant between different age groups in the same region and between the different regions in the same age group for the two populations with different immunization histories ( P<0.05). Conclusions:The COVID-19 inactivated vaccine showed a good immune effect in the healthy population in Xizang Autonomous Region, and the booster immunization helps to increase the positive rate of specific IgG antibody in healthy population.

Objective:To analyze clinical characteristics of patients of Tibetan nationality with vitiligo in the Tibet autonomous region.Methods:Clinical data were collected from 527 patients of Tibetan nationality with vitiligo, who visited Department of Dermatology, People′s Hospital of Tibet Autonomous Region from January 2018 to December 2019, including age, gender, seasons at onset, involved body sites, classification and stages of vitiligo, concomitant diseases and laboratory test results.Results:Among the 527 patients of Tibetan nationality with vitiligo, the ratio of male to female was 0.97∶1, and vitiligo usually occurred at 10 - 30 years of age. As for clinical staging, 335 (63.6%) patients were diagnosed with progressive vitiligo, and 192 (36.4%) with stable vitiligo; as for clinical classification, there were 97 (18.4%) patients with segmental vitiligo, 293 (55.6%) with vitiligo vulgaris, 79 (15%) with mixed vitiligo and 58 (11%) with unclassified vitiligo; vitiligo lesions were mainly located on the face and neck (253 cases, 48%) , followed by the trunk (148 cases, 28%) , upper limbs (64 cases, 12%) , lower limbs (46 cases, 9%) , and perineal and perianal mucosa (16 cases, 3%) ; vitiligo usually occurred in summer (198 cases, 37.6%) and spring (154 cases, 29.2%) , followed by autumn (98 cases, 18.6%) and winter (77 cases, 14.6%) ; 140 (26.6%) patients suffered from other diseases such as thyroid diseases (85 cases, 16.1%) , and 74 (14.0%) suffered from subclinical thyroid diseases; one or more serological abnormalities were observed in 22 patients, including 18 with progressive vitiligo. Compared with the patients with stable vitiligo, those with progressive vitiligo showed significantly increased thyroid stimulating hormone (TSH) levels ( P = 0.004) . Spearman rank correlation analysis showed that altitude was weakly correlated with the stage of vitiligo ( rs = -0.18, P < 0.001) , the stage of vitiligo was weakly negatively correlated with the TSH level ( rs = -0.12, P = 0.005) and complement C3 level ( rs = -0.09, P = 0.041) , and the classification of vitiligo was weakly correlated with the TSH level ( rs = -0.11, P = 0.011) . Conclusion:In this study, the patients of Tibetan nationality with vitiligo were mostly aged at 10 - 30 years, vitiligo lesions were mainly located on the face and neck, and usually occurred in spring and summer, and the prevalence of comorbid thyroid dysfunction was relatively high.

Objective:To observe and evaluate the safety and efficacy of anti-vascular endothelial growth factor (VEGF) in the treatment of eyes with macular edema (ME) secondary to branch retinal vein occlusion (BRVO) in Lhasa, Tibet.Methods:A retrospective case series. From September 2018 to January 2022, a total of 41 patients (41 eyes) with BRVO-ME, who were diagnosed in Department of Ophthalmology of Tibet Autonomous Region People’s Hospital, were included in this study. There were 21 eyes in 21 males and 20 eyes in 20 females. The median age was 53 (31,75) years. There were 24 patients with hypertension (58.8%, 24/41). Best corrected visual acuity (BCVA), ocular pressure, fundus color photography and optical coherence tomography (OCT) were performed in all eyes. The BCVA was performed using the international standard logarithmic visual acuity chart, which was converted into logarithm of the minimum angle of resolution (logMAR) BCVA for record. The foveal macular thickness (CMT) was measured by OCT. All eyes were treated with intravitreous injection of anti-VEGF drugs, once a month, among which 23 eyes (56.1%, 23/41) received intravitreous injection of ranibizumab (IVR), and 18 eyes (43.9%, 18/41) received intravitreous injection of conbercept (IVC), and were grouped accordingly. There was no significant difference in age ( Z=-0.447), gender composition ( Z=-0.485), logMAR BCVA ( t=-1.591), intraocular pressure ( t=-0.167) and CMT ( t=-1.290) between two groups ( P>0.05). During the follow-up, the same devices and methods were used at baseline to perform relevant examinations, and the changes of BCVA, intraocular pressure, CMT and new cardiovascular and cerebrovascular events were compared between baseline and the last follow-up. logMAR BCVA, intraocular pressure and CMT were compared between baseline and last follow-up using Student t test. The comparison of injection times and follow-up time between IVR group and IVC group was conducted by Mann-Whitney U test. Results:At baseline, logMAR BCVA, intraocular pressure, and CMT were 0.852±0.431, (12.5±2.5) mm Hg (1 mm Hg= 0.133 kPa), and (578.1±191.1) μm, respectively. At the last follow-up, the number of anti-VEGF drug treatments was (2.7±1.2) times; logMAR BCVA and CMT were 0.488±0.366 and (207.4±108.7) μm, respectively, with CMT > 250 μm in 14 eyes (34.1%, 14/41). Compared with baseline, BCVA ( t=4.129) and CMT ( t=-0.713) were significantly improved, with statistical significance ( P<0.001). The injection times of IVR group and IVC group were (2.6±0.9) and (3.0±1.5) times, respectively. There were no significant differences in the number of injection times ( t=-1.275), logMAR BCVA ( t=-0.492), intraocular pressure ( t=0.351) and CMT ( t=-1.783) between the two groups ( P>0.05). No new hypertension, cardiovascular and cerebrovascular events occurred in all patients during follow-up. At the last follow-up, there were no eye complications related to treatment modalities and drugs. Conclusion:Short-term anti-VEGF treatment can improve the visual acuity of BRVO secondary ME patients and alleviate ME in Lhasa, Tibet. The safety and efficacy of ranibizumab and conbercept were similar.

Objective:To evaluate the effectiveness of hepatitis B prevention and control in Tibet Autonomous Region by comparative analysis of the results of seroepidemiological surveys of hepatitis B in 2014 and 2020.Methods:The required sample size was calculated based on the estimated HBsAg positivity rates of permanent residents aged 1-4, 5-14, 15-29, and 30-69 years. A total of 7 163 people and 4 802 people were required in 2014 and 2020, respectively. The subjects were selected by stratified multistage cluster random sampling method, using questionnaires to obtain basic information, and 5 ml of venous blood was collected from each subject to detect HBsAg, anti-HBs, and anti-HBc, and rechecked the HBsAg positive samples. SPSS 22.0 software was used to analyze the survey results, calculate the positive rate and 95% confidence interval.Results:A total of 7 069 people were investigated in 2014 and 4 913 people in 2020. In 2020, the positive rate of HBsAg, anti-HBs, and anti-HBc was 9.20% (452/4 913), 37.11% (1 823/4 913), and 32.75% (1 609/4 913), respectively, and decreased by 22.95%, 15.54%, and 1.92% as compared with the rate in 2014. The positive rate of HBsAg of people aged 1-, 5-, 15- and 30-69 years in 2020 was 2.23% (8/358), 2.85% (20/701), 6.86% (69/1 006) and 12.46%(355/2 848), respectively, decreased by 61.82%, 62.75%, 54.81% and 24.21% as compared with the rate in 2014. The positive rate of anti-HBs of people aged 1-4 years was 52.79% (189/358), 10.30% increased compared with 2014; for people aged 5-, 15-, and 30-69 years was 32.67% (229/701), 37.67% (379/1 006) and 36.03%(1 026/2 848), respectively, decreased by 20.84%, 14.13% and 16.52% as compared with the rate in 2014. The positive rate of anti-HBc of people aged 1-, 5-, 15-, 30-69 years was 4.19% (15/358), 6.42%(45/701), 21.07% (212/1 006), and 46.95% (1 337/2 848), respectively, decreased by 59.63%, 58.93%, 50.49%, and 12.10% as compared with the rate in 2014.Conclusions:The prevention and control of hepatitis B in Tibet have made partial achievements. The prevalence of HBsAg among people aged 1-69 years in 2020 had declined compared with 2014, but it is still at a high epidemic level. People have a high risk of HBV infection for a low level of anti-HBs. It is necessary to strengthen the vaccination of hepatitis B further and effectively implement the strategy of blocking mothers and children of the hepatitis B virus.

Objective:To study the cross-sectional morphology of root canal system of Tibetan mandibular incisors by micro-CT.Methods:From October 2019 to October 2020, one hundred and thirty-six mandibular incisors were collected from Tibetan patients [(51.9±16.4) years old, range from 25 to 80 years] who underwent teeth extraction due to severe periodontitis at the Department of Stomatology, Tibetan Hospital of Traditional Tibetan Medicine, including 84 mandibular central incisors and 52 mandibular lateral incisors. These teeth were scanned at 23 μm voxel size resolution. Root lengths from cemento-enamel junction (CEJ) to apex of mandibular incisors were measured. According to the length, the root was divided as cervical 1/3, middle 1/3 and apical 1/3, and the numbers of root canals were recorded simultaneously. The major diameter, minor diameter, and dimension were measured per millimeter in cross section for mandibular incisor with single root canal, and the ratio of major diameter to minor diameter (D max/D min) as well as roundness were calculated for morphological analysis. The diversions and conversions from CEJ to apex in cross section were recorded for mandibular incisor with multiple root canals. Results:For mandibular central incisors with single root canal, the D max/D min was highest in middle 1/3 of the root [1.99 (1.31, 2.79)], which was significantly higher than cervical 1/3 and apical 1/3 ( P=0.010, P=0.003). The roundness was least in middle 1/3 [0.47 (0.31, 0.66)], which was significantly lower than cervical 1/3 and apical 1/3 ( P=0.010, P=0.001). For mandibular central incisor with multiple root canals, the highest incidence of multiple root canals was 40.5% (34/84), and mainly detected in middle 1/3 of the root [32.1% (27/84)]. For mandibular lateral incisor with single root canal, the roundness was greatest in apical 1/3 of the root [0.61 (0.49, 0.71)], which was significantly higher than cervical 1/3 ( P=0.001) and middle 1/3 ( P=0.001). The highest incidence of multiple root canals was 34.6% (18/52), all of which were detected in apical 1/3. Conclusions:In Tibetan mandibular central incisors, the cross-sectional morphology of root canals was long and narrow in middle 1/3, and multiple root canals were more likely to be found here. In Tibetan mandibular lateral incisors, the cross-sectional anatomy of root canal was relatively close to circle in apical 1/3, but the shape was still so irregular that one root canal may divide into two here.