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BackgroundThe role of aerosols in the transmission of SARS-CoV-2 remains debated. We analysed an outbreak involving three non-associated families in Restaurant X in Guangzhou, China, and assessed the possibility of aerosol transmission of SARS-CoV-2 and characterize the associated environmental conditions. MethodsWe collected epidemiological data, obtained a video record and a patron seating-arrangement from the restaurant, and measured the dispersion of a warm tracer gas as a surrogate for exhaled droplets from the suspected index patient. Computer simulations were performed to simulate the spread of fine exhaled droplets. We compared the in-room location of subsequently infected cases and spread of the simulated virus-laden aerosol tracer. The ventilation rate was measured using the tracer decay method. ResultsThree families (A, B, C), 10 members of which were subsequently found to have been infected with SARS-CoV-2 at this time, or previously, ate lunch at Restaurant X on Chinese New Years Eve (January 24, 2020) at three neighboring tables. Subsequently, three members of family B and two members of family C became infected with SARS-CoV-2, whereas none of the waiters or 68 patrons at the remaining 15 tables became infected. During this occasion, the ventilation rate was 0.75-1.04 L/s per person. No close contact or fomite contact was observed, aside from back-to-back sitting by some patrons. Our results show that the infection distribution is consistent with a spread pattern representative of exhaled virus-laden aerosols. ConclusionsAerosol transmission of SARS-CoV-2 due to poor ventilation may explain the community spread of COVID-19.
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BackgroundOn December 31, 2019, an outbreak of COVID-19 in humans was reported in Wuhan, and then spread fast to other provinces, China. We analyzed data from field investigations and genetic sequencing to describe the evidence and characteristics of human-to-human transmission in Guangdong Province. MethodsA confirmed COVID-19 case was defined if a suspected case was verified with positive of SARS-CoV-2 in throat swabs, nasal swabs, bronchoalveolar lavage fluid (BALF), or endotracheal aspirates by real-time reverse transcriptase polymerase chain reaction assay (RT-PCR) or genetic sequencing. Field investigations were conducted for each confirmed case. Clinical and demographic data of confirmed cases were collected from medical records. Exposure and travel history were obtained by interview. ResultsA total of 1,151 confirmed cases were identified as of February 10, 2020 in Guangdong Province, China. Of them, 697 (60.1%) cases were from 234 cluster infections. Two hundred and fourteen (18.6%) were secondary cases, in which 144 cases were from family cluster infections. With the epidemic continuing, although familial cluster events were dominated, community cluster events increased with a nosocomial event. The whole genomes within the same family cluster infections were identical, and presented a few unique single nucleotide variants (SNVs) compared with SARS-CoV-2 identified on December 2019 in Wuhan. ConclusionsWe observed evident human-to-human transmissions of SARS-CoV-2 in Guangdong, China. Although most of them were from family cluster infections, community and nosocomial infections were increasing. Our findings indicate that human-to-human transmission risks are transferring from family to community in Guangdong Province.
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Objective To analyze the clinical courses and outcomes of COVID-19 cases and the influencing factors in Guangdong province and provide basis for the formulation or adjustment of medical care and epidemic control strategy for COVID-19. Methods We collected demographic data, medical histories, clinical courses and outcomes of 1 350 COVID-19 patients reported in Guangdong as of 4 March 2020 via epidemiological investigation and process tracking. Disease severity and clinical course characteristics of the patients and influencing factors of severe illness were analyzed in our study. Results Among 1 350 cases of COVID-19 cases in Guangdong, 72 (5.3%) and 1049 (77.7%) were mild and ordinary cases, 164 (12.1%) were severe cases, 58 (4.3%) were critical cases and 7 (0.5%) were fatal. The median duration of illness were 23 days ( P 25 - P 75 : 18-31 days) and the median length of hospitalization were 20 days ( P 25 - P 75 : 15-27 days). For severe cases, the median time of showing severe manifestations was on the 12th day after onset ( P 25 - P 75 : 9th to 15th days), and the median time of severe manifestation lasted for 8 days P 25 - P 75 : 4-14 days). Among 1 066 discharged/fetal cases, 36.4% (36/99) and 1.0% (1/99) of the mild cases developed to ordinary cases and severe cases respectively after admission; and 5.2% (50/968) and 0.6% (6/968) of the ordinary cases developed to severe cases, and critical cases respectively after admission. In severe cases, 11.4% developed to critical cases (10/88). The influencing factors for severe illness or worse included male (a HR =1.87, 95% CI : 1.43-2.46), older age (a HR =1.67, 95% CI : 1.51-1.85), seeking medical care on day 2-3 after onset (a HR =1.73, 95% CI : 1.20-2.50) pre-existing diabetes (a HR =1.75, 95% CI : 1.12-2.73) and hypertension (a HR =1.49, 95% CI : 1.06-2.09). Conclusions The course of illness and length of hospitalization of COVID-19 cases were generally long and associated with severity of disease clinical outcomes. The severe cases were mainly occurred in populations at high risk. In the epidemic period, classified management of COVID-19 cases should be promoted according to needs for control and prevention of isolation and treatment for the purpose of rational allocation of medical resources.
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Objective To evaluate the application value of polarized light dermoscopy in the diagnosis of vitiligo and differential diagnosis between vitiligo and other common hypopigmented diseases.Methods Dermoscopic images of lesions of 235 patients with confirmed vitiligo (130 with active vitiligo and 105 with stable vitiligo) were collected from the database in the Department of Dermatology,Xijing Hospital from January 2018 to July 2018,and retrospectively analyzed.Meanwhile,dermoscopic images of amelanotic nevus (151 cases),pityriasis alba (113 cases) and idiopathic guttate hypomelanosis (54 cases) were compared with the dermoscopic images of vitiligo.Chi-square test was used for comparison of rates among groups.Results The prevalence of perifollicular pigmentation,reticular pigmentation,starburst,Tapioca sago and micro-Koebner phenomenon was significantly higher in the patients with active vitiligo than in those with stable vitiligo (x2 =36.5,151.2,13.0,14.9,8.4 respectively,all P ＜ 0.05).The prevalence of perifollicular pigmentation,perilesional hyperpigmentation,perifollicular telangiectasia,leukotrichia was significantly higher in patients with stable vitiligo than in those with active vitiligo (x2 =91.2,166.0,54.3,41.1 respectively,all P ＜ 0.05).The prevalence of residual perifollicular pigmentation was significantly higher in patients with active (89.2％,116/130) or stable vitiligo (54.3％,57/105) than in those with amelanotic nevus (20.5％,31/151,P ＜ 0.05),pityriasis alba (12.4％,15/113,P ＜ 0.05)or idiopathic guttate hypomelanosis (9.3％,5/54,P ＜ 0.05).Conclusion Residual perifollicular pigmentation could serve as an important feature for distinguishing vitiligo from achromic nevus,pityriasis alba and idiopathic guttate hypomelanosis,and polarized light dermoscopy shows good value in the differential diagnosis between vitiligo and some hypopigmented diseases.
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Objective To evaluate the effect of sevoflurane anesthesia on cognitive impairment in rats with traumatic brain injury. Methods One hundred and and twenty healthy male Wistar rats, aged 2-3 months, weighing 190-220 g, were assigned into 4 groups ( n=30 each) using a random number table method: control group ( group C) , traumatic brain injury group ( group T) , sevoflurane anesthesia group ( group S) , and traumatic brain injury plus sevoflurane anesthesia group ( group T+S) . A 40 g hammer was freely dropped onto the left parietal bone window from a height of 20 cm to establish the traumatic brain inju-ry model in T and T+S groups. Twelve days later, S and T+S groups inhaled 3％ sevoflurane for 3 h, and C and T groups inhaled pure oxygen for 3 h. On 1 day before anesthesia and 3 and 7 days after anesthesia, 10 rats in each group were randomly selected for performing Morris water maze test. Rats were sacrificed af-ter the end of Morris water maze test, and the hippocampal tissues were obtained for determination of the apoptosis rate of hippocampal neurons, cytoplasmic calcium concentration [Ca2+]i (by flow cytometry), expression of glucose-regulated protein 78 ( GRP78) and CCAAT∕enhancer-binding protein homologous pro-tein ( CHOP ) ( by immunohistochemistry ) , and expression of caspase-3 and caspase-12 ( by Western blot) . Results Compared with group C, the escape latency was significantly prolonged, the number of crossing platform was decreased, the apoptosis rate of hippocampal neurons and [ Ca2+] i were increased, and the expression of caspase-3, caspase-12, GRP78 and CHOP in hippocampal tissues was up-regulated in S, T and T+S groups ( P<0. 05) . Compared with T and S groups, the escape latency was significantly prolonged, the number of crossing platform was decreased, the apoptosis rate of hippocampal neurons and [ Ca2+] i were increased, and the expression of caspase-3, caspase-12, GRP78 and CHOP in hippocampal tissues was up-regulated in group T+S ( P<0. 05 ) . Conclusion Sevoflurane anesthesia can accentuate cognitive impairment in rats with traumatic brain injury, and the mechanism may be related to aggravating the degree of endoplasmic reticulum stress-induced calcium overload and increasing the apoptosis rate of hip-pocampal neurons.
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Objective To evaluate the the relationship between the mechanism underlying electroacupuncture (EA)-induced improvement of postoperative cognitive dysfunction and mitochondrion-depend-ent apoptosis in hippocampal neurons of aged rats.Methods Seventy-two healthy male Sprague-Dawley rats,aged 18 months,weighing 500-550 g,were divided into 3 groups (n =24 each) using a random number table method:control group (group C),operation group (group O) and group EA.EA was performed at Baihui and Dazhui acupoints for 30 min using disperse-dense waves,with a frequency 2/15 Hz and intensity 1 mA,once a day for 5 consecutive days in group EA.Laparotomy was performed under 3％sevoflurane anesthesia after the end of EA stimulation in O and EA groups.Morris water maze test was performed on 1 day before operation and 3 and 7 days after operation to assess the cognitive function.Rats were sacrificed after the end of Morris water maze test,brains were removed,and hippocampal tissues were obtained for detection of apoptosis rate of hippocampal neurons and expression of hippocampal caspase-3 and cytochrome c (Cyt c) by Western blot.Results Compared with group C,the escape latency was significantly prolonged after operation,the frequency of crossing the original platform was reduced,the apoptotic rate of hippocampal neurons was increased,and the expression of caspase-3 and Cyt c was up-regulated in O and A groups (P＜0.05).Compared with group O,the escape latency was significantly shortened after operation,the frequency of crossing the original platform was increased,the apoptotic rate of hippocampal neurons was decreased,and the expression of caspase-3 and Cyt c was down-regulated in EA group (P＜0.05).Conclusion The mechanism by which EA improves postoperative cognitive dysfunction may be related to inhibiting mitochondrion-dependent apoptosis in hippocampal neurons of aged rats.
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Objective To investigate the differences of X-ray findings of skeletal fluorosis between coal-burning type endemic fluo-rosis and industrial fluorosis.Methods The patients were randomly selected as research objects including 60 cases of coal-burning type endemic osteofluorosis and 60 cases of industrial osteofluorosis.The X-ray findings on the left forearm,crus and pelvic radio-graphs of these patients were analyzed retrospectively to find out the differences between skeletal fluorosis of coal-burning type endemic fluorosis and industrial fluorosis.Results X-ray features are no significant statistical differences between coal-burning type endemic fluorosis and industrial fluorosis,except these of interosseous membrane ossification of forearm and crus (forearmχ2=10.909,P<0.05;crusχ2=8.547,P<0.05),obturator membrane ossification of pelvis (χ2=36.554,P<0.05),periosteal proliferation outside bone of crus (χ2=4.937,P<0.05),and ossification of soleus (χ2=4.904,P<0.05).Conclusion The X-ray signs of endemic osteofluorosis and industrial skeletal fluorosis are almost similar,but there are some differences between them.
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Objective To evaluate the effects of sevoflurane preconditioning on postoperative cognitive dysfunction in aged rats.Methods One hundred and twenty healthy male Sprague-Dawley rats,aged 18 months,weighing 400-450 g,were randomly divided into 3 groups (n =40 each) using a random number table:control group (group C),operation group (group O),and sevoflurane preconditioning group (group Sev).In group C,the rats were only anesthetized with pentobarbital sodium and did not undergo operation.In group O,the rats were anesthetized with pentobarbital sodium and underwent 30 min of exploratory laparotomy.In group Sev,the rats inhaled 2.4％ sevoflurane for 30 min and then inhaled air for 30 min,and the other procedures were similar to those previously described in group O.At 30 min before operation and on 1st,3rd,5th and 7th days after operation,Morris water maze test was performed to record the escape latency,time of staying at the original platform quadrant and frequency of crossing the original platform.At 30 min before operation and on 1st and 7th days after operation,10 rats in each group were sacrificed and hippocampi were isolated to detect the apoptotic rate and intracellular [Ca2 +] i (using flow cytometry) and the ultrastructure of hippocampal neurons was observed with transmission electron microscope.Results Compared with group C,the escape latency was significantly prolonged,the time of staying at the original platform quadrant was shortened,the frequency of crossing the original platform was decreased,and the apoptotic rate and intracellular [Ca2 +] i were increased after operation in O and Sev groups (P ＜0.05).Compared with group O,the escape latency was significantly shorten,the time of staying at the original platform quadrant was prolonged,the frequency of crossing the original platform was increased,and the apoptotic rate and intracellular [Ca2+]i were decreased after operation in group Sev (P ＜ 0.05).Microscopic examination showed no abnormality in the ultrastructure of hippocampal neurons in group C,and the pathological changes of the ultrastructure of hippocampal neurons were obvious in group O,and were significantly attenuated in group Sev.Conclusion 2.4％ sevoflurane preconditioning can reduce postoperative cognitive dysfunction in aged rats,and regulation of imbalance of calcium homeostasis and reduction of cell apoptosis are involved in the mechanism.
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OBJECTIVE:To investigate the dissolubility of commercial metformin hydrochloride tablets from different manufactories.METHODS:The in vitro dissolubility of 14 kinds of commercial metformin hydrochloride tablets was determined by basket method and the dissolution parameters were analyzed with variance analysis method.RESULTS:The in vitro dissolubility of 14 kinds of metformin hydrochloride tablets fitted to the request of ChP2000,but the dissolution parameters were different.CONCLUSION:The statistical results indicate that there are significant differences between products from different factories(P
