ABSTRACT
BackgroundThe risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) subsequent infection among seropositive young adults was studied prospectively. MethodsThe study population comprised 3,249 predominantly male, 18-20-year-old Marine recruits. Upon arrival at a Marine-supervised two-week quarantine, participants were assessed for baseline SARS-CoV-2 IgG seropositivity, defined as a 1:150 dilution or greater on receptor binding domain and full-length spike protein enzyme-linked immunosorbent (ELISA) assays. SARS-CoV-2 infection was assessed by PCR at initiation, middle and end of the quarantine. After appropriate exclusions, including participants with a positive PCR during quarantine, we performed three biweekly PCR tests in both seropositive and in seronegative groups once recruits left quarantine and entered basic training and baseline neutralizing antibody titers on all subsequently infected seropositive and selected seropositive uninfected participants. FindingsAmong 189 seropositive participants, 19 (10.1%) had at least one positive PCR test for SARS-CoV-2 during the six-week follow-up (1.1 cases per person-year). In contrast, 1,079 (48.0%) of the 2,247 seronegative participants tested positive (6.2 cases per person-year). The incidence rate ratio was 0.18 (95% CI 0.11-0.28, p<0.00001). Among seropositive recruits, infection was associated with lower baseline full-length spike protein IgG titers (p<0.0001). Compared with seronegative recruits, seropositive recruits had about 10-fold lower viral loads (ORF1ab gene, p<0.005), and trended towards shorter duration of PCR positivity (p=0.18) and more frequent asymptomatic infections (p=0.13). Among seropositive participants, baseline neutralizing titers were detected in 45 of 54 (83.3%) uninfected and in 6 of 19 (31.6%) infected participants during the 6 weeks of observation (ID50 difference p<.0001). InterpretationSeropositive young adults had about one-fifth the risk of subsequent infection compared with seronegative individuals. Although antibodies induced by initial infection are largely protective, they do not guarantee effective SARS-CoV-2 neutralization activity or immunity against subsequent infection. These findings may be relevant for optimization of mass vaccination strategies. FundingDefense Health Agency and Defense Advanced Research Projects Agency
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OBJECTIVES@#To compare the effects of different irradiators on the establishment of osteoradionecrosis of jaw model (ORNJ) to explore an ideal modeling method.@*METHODS@#A total of 33 adult SD rats were included and randomly divided into three groups according to the radiation equipment, namely, the blank control (CN, 3 rats), group A (linear accelerator irradiation, 15 rats), and group B (small-animal irradiator irradiation, 15 rats). Groups A and B were irradiated with daily fractions of 7, 8, and 9 Gy for 5 days and further divided into three subgroups as follows: group A@*RESULTS@#At 3 weeks after dental extractions, complete gingival healing was found in the regions of dental extractions in groups A@*CONCLUSIONS@#Small-animal irradiator irradiation is an ideal device for establishing ORNJ model.
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Animals , Rats , Mandible , Molar , Osteoradionecrosis/etiology , Rats, Sprague-Dawley , X-Ray MicrotomographyABSTRACT
Objective To observe the clinical curative effect of meridian skin region drainage therapy for nerve root type of cervical spondylosis by comparing to the conventional acupuncture. Methods A total of 84 cases of cervical spondylosis were randomly divided into acupuncture group and drainage group,42 cases in each group. The drainage group was given meridian skin region drainage therapy including skin scraping, bloodletting combining with I-shaped acupuncture (acupuncture on Fengchi penetrating Fengfu,C3-C6 spinous process, Dazhui, Jianzhongshu, Jianwaishu), once a day. The acupuncture group was given conventional acupuncture mainly on Ashi points, cervical Jiaji acupoints, combining with Tianzhu, Dazhui, and Houxi, once a day. Seven times constituted one treatment course and the treatment for the two groups lasted 3 courses. During the treatment,time for the relief of the primary symptoms and signs of the two groups was observed,and pain index was evaluated with Visual Analogue Scale(VAS). After treatment , the total clinical efficacy and safety were evaluated,and the recurrence rate was investigated during the follow-up. Results(1)The total clinical efficacy of the drainage group was 95.2％ and that of the acupuncture group was 83.3％, and there were significant differences between the two groups(P < 0.05).(2)During the treatment,time for the relief of tenderness, time for the relief of pain, and time for the improvement of range of motion in the drainage group were much shorter than those in the acupuncture group (P<0.01). (3)After treatment,VAS scores of the two groups were decreased(P<0.01 compared with those before treatment),and the decrease in the drainage group was superior to that in the acupuncture group(P < 0.05).(4)The 2-month follow-up showed that the recurrence rate of the drainage group was 17.6％,and that of the acupuncture group was 38.1％,the difference being significant (P<0.05).(5)During the treatment,no obvious adverse event occurred in the two groups. Conclusion Meridian skin region drainage therapy exerts certain therapeutic effect for nerve root type of cervical spondylosis.