[Epidemiological characteristics of COVID-19 epidemic in Ejina banner, Inner Mongolia Autonomous Region, October 2021]

Objective: To understand the epidemiological characteristics of COVID-19 epidemic in Ejina banner, Inner Mongolia, in October 2021 and provide evidence for the improvement of COVID-19 prevention and control. Methods: The information about the time, area and population distributions of COVID-19 cases in Ejina before November 13, 2021 and the gene sequencing result of the isolates were collected for a statistical descriptive analysis. Results: The first COVID-19 case in Ejina occurred on 7 October, 2021. A total of 164 COVID-19 cases were reported from October 19 to November 12. Most cases were distributed in 6 communities in Darahub (156 cases, 95.12%). The result of full gene sequencing of the isolates indicted that the pathogen was Delta variant (B.1.617.2). The male to female ratio of the cases was 1.3∶1. The age of cases ranged from 1 to 85 years, and the cases aged 20-59 years accounted for 78.66%. The main clinical symptoms were sore throat (91 cases, 91.92%), cough (49 cases, 49.49%) and fever (23 cases, 23.23%). Most cases were ordinary ones (81 cases, 49.39%) and mild ones (68 cases, 41.46%). The cases were mainly detected at the isolation points (84 cases, 51.22%) and through population based nucleic acid testing (62 cases, 37.80%). The basic reproduction number (R₀) of COVID-19 was 5.3, the average incubation period was 3.9 days. The local government rapidly started Ⅳ level emergency response and conducted 10 rounds of nucleic acid tests. The transferring of travelers reduced the risk for the further spread of COVID-19 in Ejina. Conclusions: The epidemic of COVID-19 in Ejina characterized by strong transmission, short incubation period, herd susceptibility and case clustering. Delta variant (B.1.617.2) was the pathogen, which might be imported from Zeke port. Comprehensive prevention and control measures, such as closed-loop management and vaccination, should be continued. The successful transferring of the patients and travelers provided evidence for the effective and precise prevention and control of COVID-19 in a routine manner.

Purification of natural antikeratin autoantibodies from normal human serum and their effect on human keratinocytes cultured in vitro

BACKGROUND

Antikeratin (AK) autoantibodies, circulating antibodies against epidermal keratins, have been detected in all normal human sera. However, direct evidence on the biological significance of AK autoantibodies is still lacking.

OBJECTIVES

To purify AK autoantibodies from human serum and to make a preliminary study of their biological effects on human keratinocytes.

METHODS

We first extracted keratin polypeptides from human stratum corneum and analysed their purity using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Next, a keratin affinity column was prepared with the extracted keratins, and AK autoantibodies were purified from pooled normal human serum. Antibodies obtained were identified with SDS-PAGE, enzyme-linked immunosorbent assay, immunoperoxidase staining, immunoelectron microscopy and Western blotting. The biological effect of AK autoantibodies on cultured human keratinocytes was studied using a DNA synthesis assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric determination and cell cycle analysis.

RESULTS

On average, 1.83 +/- 0.24 mg of antibodies could be purified from 10 mL of pooled human serum. High-titre IgG (about 1 : 70) and low-titre IgM (about 1 : 30) AK autoantibodies were obtained. The DNA synthesis assay and MTT colorimetric determination demonstrated that AK autoantibodies have a significant dose-dependent inhibitory effect on cultured keratinocytes. Correlation coefficients in the two experiments were - 0.583 and - 0.797, respectively. Cell cycle analysis indicated that a small dose of AK autoantibodies leads to inhibition of proliferation of cultured keratinocytes, whereas a large dose of AK autoantibodies causes a visible hypodiploid peak, suggesting apoptosis of keratinocytes.

CONCLUSIONS

The present research lays a solid foundation for further investigation into the biological significance of natural AK autoantibodies.

[Experimental studies of genistein on the proliferation and apoptosis of human prolactinoma cells cultured in vitro]

AIM

To study the influence of genistein (GST) on the proliferation and apoptosis of cultured human prolactinoma cells.

METHODS

MTT method and 3H-TdR incorporation and cell cycle analysis were used to examine the changes of proliferation and DNA synthesis of human prolactinoma cells under influence of GST and beta-estradiol (E2). Tdt-mediated dUTP nick end labeling (TUNEL) were employed to observe the effect of GST and E2 on the apoptosis of human prolactinoma cells.

RESULTS

In a dose dependent manner, GST of different concentration could significantly inhibit the proliferation of human prolactinoma cells cultured in vitro. GST(10(-5) mol/L) could increase the proportion of cells in G1 phase from 55.3% up to 90.3%. E2 of different concentration could dose-dependently increase the proliferation of human prolactinoma cells. E (10(-5) mol/L) could increase the proportion of cells in G2 phase from 15.6% up to 41.8%. However, a lower suppressive proliferation of cultured human prolactinoma cells was observed with GST and E2 together. GST, not E2, could significantly induce the apoptosis of human prolactinoma cells cultured in vitro.

CONCLUSION

GST inhibits the proliferation, DNA synthesis and cell cycle of cultured human pituitary cells, and induces its apoptosis. E2 decreases partly the effect of GST on the suppression of proliferation, not apoptotic induction, of human prolactinoma cells cultured in vitro.

[The influence of acetylcholine on the proliferation of cultured human pituitary tumour cells]

AIM

To study the influence of acetylcholine on the proliferation, DNA synthesis and cell cycle of cultured human pituitary tumour cells.

METHODS

MTT method, 3H-TdR incorporation and cell cycle analysis were used to examine the changes of proliferation and DNA synthesis of human pituitary tumour cells.

RESULTS

Ach at 10(-7) mol/L - 10(-5) mol/L could decrease the 3H-TdR incorporation and the MTT A value in a dose dependent manner (P < 0.01), and the ratio of G1 phase of pituitary tumour cells increased markedly (P < 0.01). The effect of acetylcholine on the proliferation of cultured human pituitary tumour cells could be inhibited by atropine.

CONCLUSION

Ach inhibited the proliferation, DNA synthesis and cell cycle of cultured human pituitary tumour cells, and the inhibitory effect was mediated by acetylcholine receptor.

Hypoxia-inducible nuclear factors bind to an enhancer element located 3' to the human erythropoietin gene

Human erythropoietin gene expression in liver and kidney is inducible by anemia or hypoxia. DNase I-hypersensitive sites were identified 3' to the human erythropoietin gene in liver nuclei. A 256-base-pair region of 3' flanking sequence was shown by DNase I protection and electrophoretic mobility-shift assays to bind four or more different nuclear factors, at least two of which are induced by anemia in both liver and kidney, and the region functioned as a hypoxia-inducible enhancer in transient expression assays. These results provide insight into the molecular basis for the regulation of gene expression by a fundamental physiologic stimulus, hypoxia.