ABSTRACT
Objective:To measure the change in Young′s modulus of the biceps brachii during passive stretching and to assess the potential of shear wave elastography (SWE) as an auxiliary quantitative technique for assessing muscle tone.Methods:Forty-nine stroke survivors and 30 healthy subjects were evaluated using the modified Ashworth scale (MAS). According to their MAS scores they were divided into a healthy group, a healthy elbow group, an MAS class-0 group, an MAS class-1 group, an MAS class-1 + group and an MAS class-2 group. During passive extension of the subjects′ elbows, shear wave elastography was used to image the biceps brachii. Six points of the elbow were selected to record the instantaneous Young′s modulus ( EX) and calculate its change during the movement (Δ E). Those data were correlated with the MAS scores and compared among the groups. Results:Persons with higher MAS scores tended to have a higher Young′s modulus of the biceps brachii, and the modulus was likely to increase more with increases in the angle of elbow extension. From half of the range of motion to full extension there were significant differences in EX and Δ E between MAS class-0 and class-1 groups, as well as between the class-0 and class-1 + groups. There were, however, no significant differences between MAS class-1 and MAS class-1 + . Conclusions:MAS scores can usefully predict biceps brachii stiffness during passive elbow flexion. Shear wave elastography can quantify that stiffness and also muscle tone.
ABSTRACT
BackgroundAlthough inactivated COVID-19 vaccines are proven to be safe and effective in the general population, the dynamic response and duration of antibodies after vaccination in the real world should be further assessed. MethodsWe enrolled 1067 volunteers who had been vaccinated with one or two doses of CoronaVac in Zhejiang Province, China. Another 90 healthy adults without previous vaccinations were recruited and vaccinated with three doses of CoronaVac, 28 days and 6 months apart. Serum samples were collected from multiple timepoints and analyzed for specific IgM/IgG and neutralizing antibodies (NAbs) for immunogenicity evaluation. Antibody responses to the Delta and Omicron variants were measured by pseudovirus-based neutralization tests. ResultsOur results revealed that binding antibody IgM peaked 14-28 days after one dose of CoronaVac, while IgG and NAbs peaked approximately 1 month after the second dose then declined slightly over time. Antibody responses had waned by month 6 after vaccination and became undetectable in the majority of individuals at 12 months. Levels of NAbs to live SARS-CoV-2 were correlated with anti-SARS-CoV-2 IgG and NAbs to pseudovirus, but not IgM. Homologous booster around 6 months after primary vaccination activated anamnestic immunity and raised NAbs 25.5-fold. The NAb inhibition rate subsequently rose to 36.0% for Delta (p=0.03) and 4.3% for Omicron (p=0.004), and the response rate for Omicron rose from 7.9% (7/89) to 17.8% (16/90). ConclusionsTwo doses of CoronaVac vaccine resulted in limited protection over a short duration. The homologous booster slightly increased antibody responses to the Delta and Omicron variants; therefore, the optimization of booster procedures is vital. FundingKey Research and Development Program of Zhejiang Province; Key Program of Health Commission of Zhejiang Province/ Science Foundation of National Health Commission; Major Program of Zhejiang Municipal Natural Science Foundation.
