Performance analysis among multiple fully automated anti-SARS-CoV-2 antibody measurement reagents: A potential indicator for the correlation of protection in the antibody titer.

BACKGROUND: To evaluate the performance of various reagents in automated analyzers for antibody detection against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: Using 100 serum samples from 100 individual patients diagnosed with SARS-CoV-2 infection, the precision, linearity, determination agreement, and correlation of five qualitative reagents (Elecsys Anti-SARS-CoV-2, ARCHITECT SARS-CoV-2 IgG, ARCHITECT SARS-CoV-2 IgM, Access SARS-CoV-2 IgM, and SARS-CoV-2 IgM) and four quantitative reagents (Elecsys Anti-SARS-CoV-2 S, ARCHITECT SARS-CoV-2 IgG II, Access SARS-CoV-2 IgG 1st IS, and SARS-COV-2 IgG S) were analyzed. A surrogate virus-neutralizing test (sVNT) kit was used to evaluate the measurement value of each quantitative reagent corresponding to the amount of neutralizing antibody, similar to that of patients in the late stage of infection. RESULTS: Precision and linearity were found to be sufficient for clinical use. Five discrepant samples were observed in the positive and negative judgments of the qualitative reagents for IgG, and one discrepant sample was observed in the qualitative reagent for IgM. Although the measurement values of the quantitative reagents were different, they were correlated with each reagent. The reference values inferred from the sVNT were Elecsys Anti-SARS-CoV-2: 71.8 U/L, ARCHITECT SARS-CoV-2 IgGⅡ: 2976.3 AU/mL, Access SARS-CoV-2 IgG 1st IS: 689.6 IU/mL, and SARS-CoV-2 IgG S: 19.3 U/L. CONCLUSIONS: The performance observed for each anti-SARS-CoV-2 antibody detection reagent was sufficient. The reference values based on the inhibition rate of sVNT have potential as indicators of the correlation of protection and are expected to be leveraged in automated antibody tests.

Effect of albumin measurement methods on the albumin-bilirubin grade.

BACKGROUND: Albumin-bilirubin (ALBI) grade is an index of liver function based on total bilirubin (T-BIL) and albumin levels, and its usefulness has been widely reported. This study aimed to investigate the effect of different methods of measuring T-BIL and albumin levels on the ALBI grade in patients with liver disease. METHODS: In total, 170 patients from our hospital were included in this study. Correlations between T-BIL levels measured using the vanadate oxidation and enzymatic methods were analysed. Similarly, a correlation analysis of albumin levels between the bromocresol green (BCG) and modified bromocresol purple (BCP) methods was performed. Additionally, the ALBI grade was calculated for patients with liver disease, and the differences between each method of albumin measurement were compared. RESULTS: No differences were observed in the measured T-BIL values between the two methods. Contrastingly, the albumin levels of 100 random samples and 70 liver disease patients obtained using the modified BCP method were significantly lower than those measured using the BCG method. The rate of change in the modified ALBI grade between the BCG and BCP methods was 25.7%. CONCLUSIONS: Caution should be taken when comparing ALBI grades with those measured by other facilities because the method of albumin measurement can affect the ALBI grade. Standardization of albumin measurement is needed worldwide.

Serum Testosterone Is Associated With the Severity of COVID-19.

BACKGROUND/AIM: Coronavirus disease 2019 (COVID-19) is more likely to be severe in men than in women. Its association with sex hormones as an aggravating factor for male patients has been attracting attention. This study aimed to investigate whether serum testosterone is associated with the aggravation of COVID-19. PATIENTS AND METHODS: Serum testosterone concentrations in 116 male patients with COVID-19 and residual serum were measured and examined upon their admission to Sapporo Medical University Hospital between February 1, 2020 and March 31, 2021. RESULTS: Blood samples collected from these patients with COVID-19 were analyzed. The serum testosterone levels were 2.19±1.35, 1.29±0.88, and 0.75±0.58 ng/ml in mild, moderate, and severe groups, respectively. Patients with severe COVID-19 on admission had lower testosterone levels (p<0.001). At a cutoff level of 1.31 ng/ml, the area under the curve for the comparison of severe with non-severe cases was 0.825. Furthermore, serum testosterone levels negatively correlated with C-reactive protein and serum amyloid A levels but positively correlated with calcium, zinc, C3, and C4. CONCLUSION: In male patients with COVID-19, low serum testosterone levels correlated with disease severity, accompanied by a strong inflammatory reaction and proportion of complement consumption.

Coincident postsynaptic activity gates presynaptic dopamine release to induce plasticity in Drosophila mushroom bodies.

Simultaneous stimulation of the antennal lobes (ALs) and the ascending fibers of the ventral nerve cord (AFV), two sensory inputs to the mushroom bodies (MBs), induces long-term enhancement (LTE) of subsequent AL-evoked MB responses. LTE induction requires activation of at least three signaling pathways to the MBs, mediated by nicotinic acetylcholine receptors (nAChRs), NMDA receptors (NRs), and D1 dopamine receptors (D1Rs). Here, we demonstrate that inputs from the AL are transmitted to the MBs through nAChRs, and inputs from the AFV are transmitted by NRs. Dopamine signaling occurs downstream of both nAChR and NR activation, and requires simultaneous stimulation of both pathways. Dopamine release requires the activity of the rutabaga adenylyl cyclase in postsynaptic MB neurons, and release is restricted to MB neurons that receive coincident stimulation. Our results indicate that postsynaptic activity can gate presynaptic dopamine release to regulate plasticity.

The effect of androgen on the retention of extinction memory after conditioned taste aversion in mice.

Conditioned taste aversion (CTA) induced by the application of a novel taste such as sodium saccharin (Sac) as the conditioned stimulus (CS) and a malaise-inducing agent as the unconditioned stimulus (US), results in acquisition of CTA memory to Sac. In contrast, CTA is extinguished by repeated presentations of the CS without the US, resulting in acquisition of the extinction memory. We examined the effects of androgenic hormones on acquisition and retention of extinction memory in mice. We gonadectomized sexually immature mice and continuously administered androgens to these animals. After sexual maturation, the mice underwent a conditioning period followed by an extinction period. Retrieval tests revealed that the androgen-treated group showed significantly greater retention of extinction memory than the non-treated group 5 weeks later, whereas such significant difference was not observed in acquisition of extinction memory. These results demonstrate the enhancing effect of androgens on retention of extinction memory.