Isotopic Constraints on Sources and Transformations of Nitrate in the Mount Everest Proglacial Water.

Glacier melting exports a large amount of nitrate to downstream aquatic ecosystems. Glacial lakes and glacier-fed rivers in proglacial environments serve as primary recipients and distributors of glacier-derived nitrate (NO3-), yet little is known regarding the sources and cycling of nitrate in these water bodies. To address this knowledge gap, we conducted a comprehensive analysis of nitrate isotopes (δ15NNO3, δ18ONO3, and Δ17ONO3) in waters from the glacial lake and river of the Rongbuk Glacier-fed Basin (RGB) in the mountain Everest region. The concentrations of NO3- were low (0.43 ± 0.10 mg/L), similar to or even lower than those observed in glacial lakes and glacier-fed rivers in other high mountain regions, suggesting minimal anthropogenic influence. The NO3- concentration decreases upon entering the glacial lake due to sedimentation, and it increases gradually from upstream to downstream in the river as a soil source is introduced. The analysis of Δ17ONO3 revealed a substantial contribution of unprocessed atmospheric nitrate, ranging from 34.29 to 56.43%. Denitrification and nitrification processes were found to be insignificant in the proglacial water of RGB. Our study highlights the critical role of glacial lakes in capturing and redistributing glacier-derived NO3- and emphasizes the need for further investigations on NO3- transformation in the fast-changing proglacial environment over the Tibetan Plateau and other high mountain regions.

Preliminary results of anti-vascular endothelial growth factor treatment for macular edema secondary to branch retinal vein occlusion in Lhasa Tibet / 中华眼底病杂志

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.

Real-world outcomes of anti-vascular endothelial growth factor therapy for retinal vascular vein occlusion in Tibet, China.

AIM: To evaluate the outcomes of intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents for patients with retinal vein occlusion (RVO) related-macular edema (ME) in Tibetan. METHODS: A retrospective, observational, single-center study. The demographic and clinical data of 90 RVO Tibetan patients (93 eyes) treated with either ranibizumab or conbercept in Tibet Autonomous Region People's Hospital from Jan 2018 to December 2019 were collected. RESULTS: The mean patient age was 56.8±10.6y, 45 (50%) of them were female. The mean living altitude was 3867.8±567.9 m. At the last visit, the best-corrected visual acuity (BCVA) significantly increased (52.2±21.8 letters) in comparison with the baseline (38.2±24.1 letters, P<0.001); while the central retinal thickness (CRT) significantly reduced (245.5±147.6 µm) in comparison with the baseline (504.1±165.2 µm, P<0.001). The 43.0% of the eyes gained ≥15 letters, 60.2% of the eyes gained ≥10 letters, and 78.5% of the eyes gained ≥5 letters. No vision loss was noted in 92.5% of the eyes, 4 eyes lost more than 10 letters during follow-up period. The mean number of injections was 2.4±1.8. No severe ocular or systemic adverse events related to either the drug or injection were noted. CONCLUSION: Anti-VEGF therapy is effective and safe in Tibetan patients for the treatment of RVO related ME.

Clinical characteristics of 527 patients of Tibetan nationality with vitiligo / 中华皮肤科杂志

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.

Comparative study on application effect of artificial nose and heating humidification combination device in high altitude area / 中国实用护理杂志

Objective To investigate the application and effect evaluation of combined warming and humidification device in patients with artificial airway in high altitude area. Methods The convenient sampling method was used to select 225 hospitalized patients in the Department of Critical Care Medicine of the People′s Hospital of Tibet Autonomous Region from January to June 2018. According to the order of admission time, they were divided into two groups: observation group (125 cases) and control group (100 cases). The observation group was humidified by artificial nose, while the control group was humidified by heating and humidifying device. The phlegm properties and scab formation were observed in the two groups. The ambient temperature, humidity and airway temperature were measured at 3:00, 9:00, 15:00 and 21:00 every day. The average values of four measurements were taken. The levels of CO2 partial pressure and oxygen partial pressure were recorded by blood gas analysis. χ2was used to compare the differences between the 2 groups. Results There was no difference in sputum properties between the two groups before humidification. The incidence of grade II and grade III mucous phlegm in the observation group was 46, 48 and 65 on the first, second and third day after humidification, while that in the control group was 13, 9 and 10 respectively. The difference between the two groups was statistically significant (χ2=16.266, 25.387, 44.100, P<0.01). On the 2nd and 3rd day, the oxygen partial pressure levels of the observation group were (92.62 ± 5.73), (91.34 ± 4.82) mmHg, and those of the control group were (96.17 ± 3.60), (95.53 ± 2.96) mmHg, respectively. The difference between the two groups was statistically significant (t=5.697, 8.045, P<0.01). The sputum scab formation and airway temperature in the observation group were 41 cases and(29.89±1.95)℃ respectively after 3 days of humidification, 7 cases and(34.79±1.82)℃respectively in the control group. The difference between the two groups was statistically significant (χ2= 22.035, t =- 26.031, P < 0.01). Conclusion The combination of heating and humidifying device can effectively improve the sputum properties, reduce the formation of sputum scab, effectively improve the level of carbon dioxide, without increasing the workload.