Demographic Factors Among HIV Confirmed Blood Donors from 2013 to 2021 in Shenzhen.

Background: New HIV (Human immune deficiency virus) infections are continuously increasing in China and it remains a huge challenge to blood donation. As access to health services has affected by COVID-19 (Corona virus disease 2019) pandemic, a drop in new diagnoses (especially HIV) was observed worldwide. Methods: During 2013-2021, 735,247 specimens from unpaid blood donors collected by Shenzhen Blood Center underwent ELISA (Enzyme -linked immunosorbent assay) and NAT (Nucleic acid test). Samples with reactivity results were sent to the Shenzhen Center for Disease Control and Prevention for WB (Western blot). All data were statistically analyzed by the Chi-Square test. Results: From 2013 to 2021, the prevalence of HIV among male blood donors was higher than in females (P < 0.01). During the COVID-19 pandemic, the prevalence of HIV among repeat blood donors decreased significantly compared to 2019 (P < 0.05), and the characteristics of blood donors changed in 2020 compared to 2019 and 2021. Conclusion: The high proportion of female blood donors would help prevent HIV from getting into the blood supply. The COVID-19 pandemic affected the demographics of blood donors as well as the prevalence of HIV among repeat blood donors. An increased number of repeat blood donors can help decrease the risk of HIV transfusion transmission during the epidemic.

[Scale Effects of Landscape Pattern on Water Quality in Dongjiang River Source Watershed].

Based on water quality monitoring data and land use data, Dongjiang River source watershed water quality variation characteristics from 2017 to 2019 and the relationships between the landscape pattern of the Dongjiang River source watershed and water quality were analyzed using spatial analysis, correlation analysis, and redundancy analysis. The results showed that:① the water quality of the Dongjiang River source watershed improved overall, but the total nitrogen pollution was still severe. As of 2019, the annual average concentration of total nitrogen in all sampling points exceeded the type Ⅲ water quality standard. ② At the landscape level, water quality was positively correlated with landscape shape index, number of patches, and Shannon's diversity index but negatively correlated with largest patch index and aggregation index. Considering the land use type, construction land was the primary source of total nitrogen and total phosphorus. Landscape shape index and number of forest patches were positively correlated with NH4+-N. The number of forest patches was positively correlated with total phosphorus. However, the largest patch index and aggregation index of the forest were negatively correlated with total phosphorus. The number of patches of grassland was positively correlated with total phosphorus. The aggregation index of grassland was negatively correlated with total phosphorus. ③ It is suggested that management departments should focus on the optimization of the landscape pattern within the 2000 m buffer zone of monitoring points. The reasonable allocation of urban sewage-centralized treatment facilities, strengthening management of abandoned mining areas, improvement of intensive treatment of cultivated land, and construction of shelterbelt in areas where cultivated land is concentrated are beneficial for the water quality of Dongjiang River source watershed.

[Evaluation of the Cutoff of Anti-HCV Antibody Enzyme-Linked Immunosorbent Assay in 7 Blood Station Laboratories].

OBJECTIVE: To evaluate the necessity and suitability of the anti-HCV ELISA teot gray zone setted up by 7 blood station laboratories. METHODS: 7 blood station laboratories were coded as 1, 2, 3, 4, 5, 6 and 7 respectively; 8 kinds of ELISA reagents were coded as A, B, C, D, E, F, G and H respectively. 1 or 2 of 8 ELISA reagents produced by different manufactories were used to detect the anti-HCV in specimens of same group by 7 blood station laboratories; the Westen blot was used to detect the specimens with difference of detected results so as to difine the serological status of specimens. The true positive rate of specimens detected by laboratories and gray zone-comfirined positive rate of specimens were accounted so as to analyze the necessity of setting up the gray zone for anti-HCV ELISA test of 7 blood station laboratories; the optimal cut-off value for anti-HCV ELISA test was determined in 7 blood station laborafories by ROC curve and the changes of sensitivity and specificity of 3 different cut-off value(laboratory work cut-off value, manifactory-recommended cun-off value and optimal cut-off value) were compared so as to analyze the suitability of gray zone for anti-HCV ELISA test in 7 blood station laboratories. RESULTS: The true positive rate detected by 7 blood station laboratories, out of which coded 1 laboratory used 2 kinds of coded A, B reagents was 95.40%(1A), 99.23% (1B), 94.25% (2C), 96.17% (3D), 98.08% (4E), 96.93% (5F), 97.32%(6G) and 93.10%(7H). Except for 2C(94.25%) and 7H(93.10%), the true positive rate detected by laboratoies which not sutted up gray zone, the gray zone-con-firmed positive rate in 6 blood station laboratories setted up gray zone: was 0.00%, 0.00%, 21.43%, 0.00%, 0.00%, 0.00% and 38.89%. The comparison of 3 different cut-off valuces by ROC curve showed that the anti-HCV cut-off values in 5 laboratories(1B, 2C, 4E, 5F and 6G) were as follows: optimal cut-off value＞manufactory recommeded cut-off value＞laboratory work cut-off value, thus use of manufactory-recommeded cut-off value abreadly has reached the high sensitivity requinements for laboratory screening; however, the optimal cut-off value in laboratories 1A, 3B and 7H, thas the appropriate gray zone should be used. In 6 laboratories setting up gray zone, the gensitivity in 3D, 7H laboratories only a little improved (1.60% and 2.70% raspectively) in Eamparison between laboratory work cut-off value and manufactorg-recommeded cut-off value; moreover, the sensitivity in other laboratories not is changed, but the specificity decreased (0.20%-0.50%). CONCLUSION: In addition to setting up the appropriate gray zone in laboratories 1A, 3D and 5H, the gray zone in other laboratories may be cancelled. Even in the same laboratory, the setting up the gray zone also should be scientifically assessed, the same scale cannot be blindly used, thus appropniate strategies should be established.

[Effect of size and number of aerobic granules on nitrification and denitrification].

Based on experimental results, a one dimension dynamic model was developed for describing the growth, maintenance and decay processes of microbes using multi substances, and consequently, the effect of size and number of aerobic granules on nitrification and denitrification were investigated. It was found that the consuming of ammonia nitrogen increased with the larger number of granules given the same biomass amount, indicating that the consumption of ammonia was dependent on the surface area of granules. The resulting amount of NO2(-) -N and NO3(-) -N was dependent not only on the amount but also on the diameter of granules, and the effect of the diameter became negligible only when the ammonia concentration was very low, suggesting the penetration depth of oxygen determines the production of NO2(-) -N and NO3(-) -N. Regarding on denitrification, for those granules with the diameter more than 1 000 microm, the denitrification increased with the increase of diameter, however, for those ones less than 1 000 microm the effect of diameter became negligible, indicating that the limitation of oxygen diffusion in granules of big granules more than 1 000 microm could help the process of denitrification.

[Effect of Escherichia coli lipopolysaccharide on mineralized matrix formation in vitro differentiation human dental pulp cell].

OBJECTIVE: To investigated the effect of Escherichia coli (Ec) LPS on alkaline phosphatase (ALP) activity and expression of dentin sialophosphoprotein (DSPP) and osteocalcin (OCN) genes in vitro differentiation human dental pulp cell. METHODS: Odontoblast-like cells were cultured, cells exposed to Ec LPS for 12 h, total RNA was isolated and DSPP, OCN transcripts were examined by real-time RT-PCR. ALP kit were used to assessed the changes of ALP activity. RESULTS: Real-time RT-PCR analysis indicated that Ec LPS induced about a 3.6-fold decrease for DSPP gene and a 1.6-fold decrease for OCN gene in odontoblast-like cells as compared with controls. At the same time, cells treated with LPS could depress ALP activity from (1156.10 +/- 100.60) pmol x h(-1) x ng(-1) down to (884.80 +/- 26.72) pmol x h(-1) x ng(-1). CONCLUSIONS: These results indicate that exposure of odontoblast-like cells to LPS can alter cells function by downregulating cell markers of odontoblastic activity.

[Isolation, cultivation and initial identification of Nanobacteria from dental pulp stone].

OBJECTIVE: To isolate Nanobacteria from dental pulp stone and perform culturing and the identification of Nanobacteria. METHODS: Freshly collected 27 dental pulp stones were divided into nine samples. Each sample contained three dental pulp stones. All samples were used for the isolation and culture of Nanobacteria. The shape and the growth characteristics of the cultured bacteria were observed. Nanobacteria were identified by von Kossa staining, immunohistochemical staining and indirect immunofluorescence staining, double staining including Hoechst staining and von Kossa staining. RESULTS: The characteristics growth and morphology of the bacteria detected in seven samples were similar to Nanobacteria. von Kossa staining, immunohistochemical staining, indirect immunofluorescent staining were positive for Nanobacteria. In double staining method, Hoechst staining of the samples was negative for Nanobacteria, but von Kossa staining was positive. Hoechst staining of the dental pulp cells was positive. No Nanobacteria was found in the other two samples. CONCLUSIONS: The bacteria isolated from dental pulp stone in this study was similar to Nanobacteria in terms of growth rate, morphology and staining properties. These unusual properties of the bacteria may play an important role in the formation of pulp stone.

Expression of toll like receptor 4 in normal human odontoblasts and dental pulp tissue.

The aim of the study was to determine the expression of TLR4 in odontoblasts and the dental pulp. Odontoblasts and pulp tissues were collected from freshly extracted human wisdom teeth. Reverse transcription-polymerase chain reaction and Western blotting were performed to detect TLR4 mRNA and protein expression, respectively. Immunohistochemical staining was used to determine the distribution of TLR4 in odontoblasts and the pulp. Scanning electron microscopy (SEM) was applied to observe the morphology of odontoblasts. It was demonstrated that TLR4 mRNA and protein expressions were both present in cells of odontoblast layer and pulp tissues and that TLR4 expression was distributed in odontoblasts and some pulpal vascular endothelial cells. SEM revealed the integrity of the odontoblast cell-layer and the well-preserved morphology of individual odontoblast cells. These findings suggest that TLR4 expressed in odontoblasts may play an important role in the dental immune defense.