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【Objective】 To detect the anti-SARS-CoV-2 antibody levels in blood donors in Guangzhou, so as to provide laboratory data support for the collection and clinical use of convalescent plasma. 【Methods】 Anti-SARS-CoV-2 antibodies were measured by ELISA in qualified donors. Among them, 326 donors who gave blood in February 2023 were tested for IgG antibodies, 444 donors were tested for neutralizing antibodies. In July 2023, 398 donors were tested for IgG and IgM. 【Results】 399 of 724 blood samples diluted with normal saline (1∶160) were IgG reactive, with a reactive rate of 55.11%. Chi-square test showed that there was a significant difference in the reactive rate of IgG among samples collected at different times (25.46% in February vs 79.40% in July, χ2=210.74, P<0.01, 95%CI: 7.97, 15.98), but there was no significant difference in the reactive rate between different genders and different age groups. IgM was detected in 5 of 398 blood samples, with a reactive rate of 1.26%. The IgG test results of these five blood donors were all reactive, whereas the nucleic acid test results were negative. Neutralizing antibody was detected in 440 of 444 blood samples, with a reactive rate of 99.10%, and 71.59% of the reactive donors had a neutralizing antibody level of 10 μg/mL or more. 【Conclusion】 Blood donors in Guangzhou have a high level of SARS-CoV-2 antibody, which is sufficient to provide convalescent plasma for clinical treatment.
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Objective To explore the relationship of changes in bone mineral density and bone me-tabolism indicators with osteoporosis in elderly patients with hemiplegia after cerebral infarction.Methods A total of 197 elderly patients suffering post-stroke hemiplegia admitted to our hospital were enrolled between February 2018 and February 2021.Their bone mineral density and bone metabolism indicators were analyzed based on gender,disease course and hemiplegia severity.According to disease severity,they were divided into mild group(112 cases),moderate group(62 cases)and severe group(32 cases).Results Among the 197 elderly patients,83(42.13％)had osteoporosis.The males had significantly higher bone mineral density of proximal femur and levels of bone alkaline phosphatase(BALP)and osteocalcin,and lower levels of serum type Ⅰ collagen(CICP)and C-terminal telopeptides of type Ⅰ collagen(CTXI)than the females(P＜0.01,P＜0.05).Compared with the patients with hemiplegia course for 3-6 months,bone mineral density values of greater trochanter and total hip,and levels of BALP and osteocalcin were obviously de-creased,while levels of CICP and CTXI were notably increased in those with the course of 7-12 months and 13-24 months(P＜0.05).Compared with the mild group,bone mineral density val-ues of greater trochanter and total hip,and levels of BALP and osteocalcin were significantly de-creased,while levels of CICP and CTXI were significantly increased in moderate group and severe group(P＜0.05).Compared with the moderate group,bone mineral density values of greater tro-chanter,intertrochanteric site and total hip were significantly decreased in the severe group(P＜0.05).The bone mineral density of above parts was negatively correlated with CICP levels(r=-0.458,r=-0.403,r=-0.355,r=-0.482,P＜0.01)and CTXI levels(r=-0.305,r=-0.291,r=-0.273,r=-0.384,P＜0.05,P＜0.01),while positively correlated with BGP level(r=0.476,r=0.428,r=0.386,r=0.518,P＜0.01).Conclusion The incidence of osteoporosis is quite higher in the elderly patients with post-stroke hemiplegia.There exist bone mineral density decline and abnormal bone metabolism,and their changes are related to gender,course and severi-ty of hemiplegia.