Recent Advances in Material Technology for Leukemia Treatments.

Leukemia is a widespread hematological malignancy characterized by an elevated white blood cell count in both the blood and the bone marrow. Despite notable advancements in leukemia intervention in the clinic, a large proportion of patients, especially acute leukemia patients, fail to achieve long-term remission or complete remission following treatment. Therefore, leukemia therapy necessitates optimization to meet the treatment requirements. In recent years, a multitude of materials have undergone rigorous study to serve as delivery vectors or direct intervention agents to bolster the effectiveness of leukemia therapy. These materials include liposomes, protein-based materials, polymeric materials, cell-derived materials, and inorganic materials. They possess unique characteristics and are applied in a broad array of therapeutic modalities, including chemotherapy, gene therapy, immunotherapy, radiotherapy, hematopoietic stem cell transplantation, and other evolving treatments. Here, an overview of these materials is presented, describing their physicochemical properties, their role in leukemia treatment, and the challenges they face in the context of clinical translation. This review inspires researchers to further develop various materials that can be used to augment the efficacy of multiple therapeutic modalities for novel applications in leukemia treatment.

Cadmium disrupts spermatogenic cell cycle via piRNA-DQ717867/p53 pathway.

Cadmium (Cd) is a harmful environmental pollutant that disrupts public health, including respiratory, digestive, and reproductive systems. In this study, male rats were exposed to CdCl2 at a dose of 3 mg/kg by oral for 28 days to investigate the impact on spermatogenesis. Testis tissue samples were collected after sacrifice, and piRNA expression levels were measured using piRNA microarray and qPCR. PiRNAs, specialized molecules involved in spermatogenesis, were examined. CdCl2 exposure led to disrupted piRNA expression, particularly in piRNA-DQ759395 in rats. This piRNA was found to have a binding site with p53, and a similar piRNA-DQ717867 was discovered in mice. In GC-2spd cells, CdCl2 exposure increased piRNA-DQ717867 expression, which resulted in cell cycle arrest and abnormal expression of cell cycle-related proteins. The activation of p53-related pathways and disruptions in cell cycle regulation were also observed. Antagomir-717867 transfections and PFT-a pretreatment in GC-2spd cells supported the involvement of piRNA-DQ717867 in regulating cell cycle-related proteins. This study suggests that Cd exposure induces abnormal expression of piRNA-DQ759395 in rat testis and that piRNA-DQ717867 may regulate p53, causing cell cycle abnormalities in GC-2spd cells. These findings help understand the mechanisms of male reproductive toxicity caused by Cd exposure and emphasize the role of piRNAs in cell cycle regulation and male reproductive health.

Adverse associations between maternal deoxynivalenol exposure and birth outcomes: a prospective cohort study in China.

BACKGROUND: Deoxynivalenol (DON), one of the most prevalent mycotoxins, has been found to cause fetal growth retardation in animals. However, limited evidence exists regarding its effects on pregnant women. METHODS: Maternal urinary concentration of total DON (tDON) and free DON (fDON) in the second trimester was measured using liquid chromatography with tandem mass spectrometry. Provisional daily intake (PDI) of DON was calculated based on tDON concentration. Linear and logistic regression models were used to evaluate the association between DON exposure levels and birth weight, birth length, and the risk of small for gestational age (SGA). RESULTS: Among 1538 subjects, the median concentrations of tDON and fDON were 12.1 ng/mL and 5.1 ng/mL, respectively. The PDI values revealed that the median DON intake was 0.7 µg/kg bw, and 35.9% of the total population exceeded the provisional maximum tolerable daily intake (PMTDI) of 1 µg/kg bw. Compared with the lowest tertile, birth weight decreased by 81.11 g (95% CI: -127.00, -35.23) for tDON (P-trend < 0.001) and 63.02 g (95% CI: -108.72, -17.32) for fDON (P-trend = 0.004) in the highest tertile. Each unit increase in Ln-tDON and Ln-fDON was also inversely associated with birth weight. Furthermore, compared to those who did not exceed PMTDI, pregnant women whose PDI exceeded PMTDI had lower birth weight (ß = -79.79 g; 95% CI: -119.09, -40.49) and birth length (ß = -0.21 cm; 95% CI: -0.34, -0.07), and a higher risk of SGA (OR = 1.48; 95% CI: 1.02, 2.15) in their offspring. Similar associations with birth weight, birth length, and SGA were found when comparing the highest tertile of PDI to the lowest tertile (all P-trend < 0.05). CONCLUSIONS: Maternal DON exposure is related to decreased birth weight. Our findings implicate that DON exposure during pregnancy may cause fetal growth faltering, and measures should be taken to reduce DON exposure in pregnant women.

Toxicological characteristics of drinking water in two large-scale municipal water supply systems of a metropolitan city in Central China.

Drinking water safety is threatened by numerous toxic organic pollutants difficult to chemically monitor. This study aimed to determine the toxicological profiles of organic extracts (OEs) of water samples from source to tap in two drinking water supply systems in a metropolitan city, Central China, during different hydrological periods. Mortality, DNA damage, growth, and development of Caenorhabditis elegans were evaluated following exposure to OEs. The median lethal doses of OEs of drinking water samples (n = 48) ranged from 266 REF (relative enrichment factor) to > 1563 REF. When tested at a dose of 100 REF, 56.25% (27/48) of OEs induced genotoxicity, 4.17% (2/48) inhibited the growth, and 45.83% (22/48) decreased the offspring number in C. elegans. No clear temporal-spatial variation patterns of the OEs toxicity indicators were observed. The correlations among the toxicity indicators were generally poor. The observed toxicities were not closely related to the level of dissolved organic carbon in drinking water. These findings support using multiple endpoint bioassays, such as C. elegans-based approaches, as complementary tools to conventional chemical analysis for drinking water quality monitoring.

Cancer cell membrane camouflaging mesoporous nanoplatform interfering with cellular redox homeostasis to amplify photodynamic therapy on oral carcinoma.

The efficacy of photodynamic therapy (PDT) is still limited by the inefficient utilisation of generated ROS in tumours due to cellular redox homeostasis. To improve the therapeutic efficacy for oral carcinoma, biomimetic cell membrane-coated mesoporous nanoplatform was tailored to interfere with cellular redox homeostasis for amplified PDT. In this study, CAL-27 cancer cell membrane (CM) was encapsulated onto the mesoporous silica NPs (MSN), which were preloaded with Chlorin e6 (Ce6) and Curcumin (Cur). The biomimetic nanoparticles displayed a size of around 120 nm, which had excellent cytotoxicity under a laser and increased uptake ability to tumour cell. After internalised by cancer cells, the released Cur could effectively disturb ROS-defence system by suppressing TrxR activity, and decreasing TrxR-2 expression (p < 0.05), leading to enhanced cancer cell killing ability of PDT. The biomimetic system was found to selectively accumulate in the tumour due to its homologous targeting capability and inhibit tumour growth significantly. In a word, the biomimetic nanoplatform apparently enhanced the therapeutic effect of PDT on tumours by Cur disturbing the ROS-defence system, which exhibited a new way to enhance PDT.

Associations of fine particulate matter and its metal constituents with blood pressure: A panel study during the seventh World Military Games.

Evidence is needed to elucidate the association of blood pressure (BP) changes with metal constituents in fine particulate matter (PM2.5). Therefore, we designed a longitudinal panel study enrolling 70 healthy students from Wuhan University in the context of the seventh World Military Games (the 7th WMG) from September 2019 to January 2020. A total of eight visits were conducted before, during, and after the 7th WMG. During every visit, each participant was asked to carry a personal PM2.5 monitor to measure hourly PM2.5 levels for three consecutive days. Questionnaire investigation and physical examination were completed on the fourth day. We analyzed ten metal constituents of ambient PM2.5 collected from the fixed station, and blood pressure was recorded during each visit. The linear mixed-effects models were performed to evaluate associations of metal constituents and blood pressure measurements. We observed a dramatic variation of PM2.5 concentration ranging from 7.38 to 132.04 µg/m3. A 10 µg/m3 increment of PM2.5 was associated with an increase of 0.64 mmHg (95% CI: 0.44, 0.84) in systolic BP (SBP), 0.40 mmHg (0.26, 0.54) in diastolic BP (DBP), 0.31 mmHg (0.15, 0.47) in pulse pressure (PP) and 0.44 mmHg (0.26, 0.62) in mean artery pressure (MAP), respectively. For metal constituents in PM2.5, robust positive associations were observed between BP and selenium, manganese, arsenic, cadmium, and thallium. For example, for an IQR (0.93 ng/m3) increment of selenium, SBP and MAP elevated by 0.98 mmHg (0.09, 1.87) and 0.71 mmHg (0.03, 1.39), respectively. Aluminum was found to be robustly associated with decreased SBP, DBP, and MAP. The study indicated that exposure to PM2.5 total mass and metal constituents including selenium, manganese, arsenic, cadmium, and thallium were associated with the elevated BP.

Efficient local delivery of FK506 using blocking patches in psoriasis.

FK506 is a local drug that is commonly used in the treatment of psoriasis. Its clinical application, however, is limited by its transdermal drug delivery rate, the time-consuming, and the greasy therapy. In this study, which was inspired by local block injection used in the clinical treatment for keloid, a hyaluronic acid (HA) based system to transport FK506 into the skin to treat psoriasis, named blocking patch (BP) was developed. BP has a complete appearance, sufficient puncture strength, and is virtually non-irritating in vivo. By confocal fluorescence microscopy, BP loaded with FK506 (FK506-BP) showed satisfactory transdermal release ability in vivo. Further animal studies revealed that FK506-BP showed a good anti-inflammatory ability in the imiquimod (IMQ)-induced mouse psoriasis-like dermatitis and inhibited the activation of associated immune cells. This study indicates that BP as a novel delivery system, realizes an efficient local delivery of FK506 in psoriasis and holds great potential in transdermal delivery.

A Biomimetic Metal-Organic Framework Nanosystem Modulates Immunosuppressive Tumor Microenvironment Metabolism to Amplify Immunotherapy.

In the immunosuppressive tumor microenvironment (iTME), lactate secretion by cancer cells facilitates cell escape via M1 to M2 macrophage polarization, and T cell exhaustion. Therefore, lactate is a promising tumor immunotherapy target. In this study, we constructed a biomimetic nanosystem to modulate iTME metabolism to amplify immunogenic cell death (ICD)-induced immunotherapy. Metal-organic frameworks were coated with platelet membranes (PM) for tumor site-specific delivery and rationally designed to carry lactate oxidase (Lox) which catalytically consumed lactate, while oxaliplatin (Oxa) induced ICD. Due to PM-mediated targeting, the biomimetic nanosystem selectively accumulated in tumors and inhibited tumor growth. Encouragingly, due to effective iTME modulation, enhanced cytotoxic T cell infiltration in tumors was observed. Also, tumor-associated macrophage (TAM) phenotypes were polarized from M2 to M1 types, and regulatory T cell (Treg) levels decreased in vivo. Increased CD8+ T to CD4+ T cell ratios in peripheral blood and spleen were also observed. Thus, our biomimetic nanosystem effectively modulated the iTME and inhibited tumor growth by consuming lactate and amplifying ICD-induced immunotherapy. We provide new avenues into cancer immunotherapy, with a specific emphasis on iTME modulation, which lays the foundation for translational biomimetic nanosystems in clinical settings.

Sleep duration and metabolic body size phenotypes among Chinese young workers.

The evidence linking sleep duration and metabolic body size phenotypes is limited, especially in young adulthood. In this study, we aimed to examine the association between sleep duration and metabolic body size phenotypes among Chinese young workers and investigate whether discrepancies exist among shift and non-shift workers. A cross-sectional study was performed between 2018 and 2019 in Wuhan, China and 7,376 young adults aged 20-35 years were included. Self-reported sleep duration was coded into four groups: <7, 7-8, 8-9, and ≥9 h per day. Participants were classified into four metabolic body size phenotypes according to their body mass index and metabolic health status: metabolically healthy normal weight, metabolically unhealthy normal weight, metabolically healthy overweight/obesity (MHO), and metabolically unhealthy overweight/obesity (MUO). Multinomial logistic regression models were used to explore the associations between sleep duration and metabolic body phenotypes. Compared with those who slept 7-8 h each night, those with sleep duration <7 h per day had higher odds of MHO (OR 1.27, 95% CI: 1.02-1.56) and MUO (OR 1.22, 95% CI: 1.03-1.43), irrespective of multiple confounders. Stratification analyses by shift work showed that the association between short nighttime sleep and increased odds of MUO was only observed in shift workers (OR 1.26, 95% CI 1.03-1.54). Sleep duration is independently associated with metabolic body size phenotypes among Chinese young adults, while shift work could possibly modulate the association. These results may provide evidence for advocating adequate sleep toward favorable metabolic body size phenotypes in young workers.

Microneedle Patch Delivery of Methotrexate-Loaded Albumin Nanoparticles to Immune Cells Achieves a Potent Antipsoriatic Effect.

Introduction: Transdermal drug delivery provides a desirable alternative method of penetrating the skin for psoriasis treatment, by virtue of its ability to dampen the overactivation of immune cells and inflammation, while attenuating the detrimental effects of systemic administration. Lymph nodes (LNs), as a critical organ of the lymphatic and the acquired immune system, are suitable sites for drug homing to suppress the immune cells. Methods: In this context, we developed a microneedle (MN) patch that delivers nanodrugs locally to LNs for improving the antipsoriatic treatment. In this study, human serum albumin nanoparticles carrying methotrexate (HM) were synthesized and loaded into hyaluronic acid (HA)-based microneedles (HM/MN). Results: The patch showed an excellent ability to pierce the skin, which enhanced drug delivery. In a mouse model of psoriasis, the HM/MN patch significantly prevented the erythema with decreased skin thickness, thus inhibiting the progression of psoriasis. Further analysis for immune cells in LNs, the percent of dendritic cells (DC) and T cells reduced after the local treatment with HM/MN. Notably, the feasibility of targeted delivery of methotrexate to LNs using nanoparticles was verified by detecting increased accumulation of methotrexate in LNs. In addition, the HM/MN patch pronouncedly decreased the levels of tumor necrosis factor α and interleukin 6 in the skin. Conclusion: The results suggested the high efficacy of using the HM/MN patch to treat psoriasis, and provided new insight into the mechanism of the transdermal drug delivery system.

Exposure assessment of urinary deoxynivalenol in pregnant women in Wuhan, China.

Deoxynivalenol (DON) is a ubiquitous trichothecene mycotoxin in food. DON and its modified forms can cross the placental barrier and influence the foetus' health. Limited information is available on exposure of dietary DON intake of pregnant women in China recently. We estimated the exposure of dietary DON intake of pregnant women in a large sample size (n = 2534) from China. The total DON (tDON) and free DON (fDON) biomarkers in urine were detected by liquid chromatography-tandem mass spectrometry. The mean concentration of tDON was 34.8 ng/mg creatinine, and the fDON was 15.9 ng/mg creatinine. The estimated exposure of dietary DON intake was 0.96-1.91 µg/kg bw/day, and the difference in exposure of DON between the first and second trimesters was statistically insignificant. Approximately 26%-60% of individuals exceeded the provisional maximum tolerable daily intake (PMTDI). The age, pre-pregnancy BMI, and the sampling seasons may be the risk factor for the occurrence of exceeding PMTDI. This survey is the first exposure biomarker for DON in a large sample size from pregnant women in China. We found that the dietary DON exposure in pregnant women was relatively high and particular concern should be paid to the DON exposure during pregnancy.

Recent advances of nanodrug delivery system in the treatment of hematologic malignancies.

Although the survival rate of hematological malignancies (HM) has increased in recent years, the unnecessary adverse effect to the body is usually generated by the traditional chemotherapy for HM due to the lack of specificity to tumor tissue. Nanodrug delivery systems have exhibited unique advantages in targetability, stability and reducing toxicity, attracting wide concern, which is expected to be the prevalent alternative for the treatment of HM. In this review, we systemically introduced the current therapeutic strategies and the categories of HM. Subsequently, five key factors including circulation, targeting, penetration, internalization and release involving in tailoring nanoparticles were demonstrated, followed by the introduction of the development of nanodrug delivery-traditional synthetic nanomaterilas, biomimetic cell membrane coating nanomaterials, cell-based nanomaterials as well as immunotherapy combined with nanodrug. Afterwards, the recent advances of nanodrug delivery system for the treatment of HM were introduced. Moreover, the challenge and prospect of nanodrug delivery system in treating HM were discussed. The promising drug delivery system will provide new therapeutic avenues for the treatment of HM.

Short-term exposure to fine particulate matter and its constituents may affect renal function via oxidative stress: A longitudinal panel study.

Exposure to fine particulate matter (PM2.5) has been reported to increase the risks of chronic kidney disease. However, limited research has assessed the effect of PM2.5 and its constituents on renal function, and the underlying mechanism has not been well characterized. We aimed to evaluate the association of PM2.5 and its constituents with kidney indicators and to explore the roles of systematic oxidative stress and inflammation in the association. We conducted a longitudinal panel study among 35 healthy adults before-, intra- and after-the 2019 Wuhan Military World Games. We repeatedly measured 6 renal function parameters and 5 circulating biomarkers of oxidative stress and inflammation at 6 rounds of follow-ups. We monitored hourly personal PM2.5 concentrations with 3 consecutive days and measured 10 metals (metalloids) and 16 polycyclic aromatic hydrocarbons (PAHs) components. The linear mixed-effect models were applied to examine the association between PM2.5 and renal function parameters, and the mediation analysis was performed to explore potential bio-pathways. PM2.5 concentrations across Wuhan showed a slight decrease during the Military Games. We observed significant associations between elevated blood urea nitrogen (BUN) levels and PM2.5 and its several metals and PAHs components. For an interquartile range (IQR) increase of PM2.5, BUN increased 0.42 mmol/L (95% CI: 0.14 to 0.69). On average, an IQR higher of lead (Pb), cadmium (Cd), arsenic (As), selenium (Se), thallium (Tl) and Indeno (1,2,3-cd) pyrene (IPY) were associated with 0.90, 0.65, 0.29, 0.27, 0.26 and 0.90 mmol/L increment of BUN, respectively. Moreover, superoxide dismutase was positively associated with PM2.5 and mediated 18.24% association. Our research indicated that exposure to PM2.5 might affect renal function by activating oxidative stress pathways, in which the constituents of Pb, Cd, As, Se, Tl and IPY might contribute to the associations.

Bentazone in water and human urine in Wuhan, central China: exposure assessment.

Bentazone is a widely used post-emergence herbicide, while no data was available on its concentrations in tap water from China and in urine among the general population. It was determined in the source (Wuhan section of the Yangtze River watershed), treated, and tap water (n = 20, 20, and 170, respectively) in different seasons (2019) in Wuhan, central China. Also, urine samples (n = 38) collected from healthy adults in Wuhan (September 2020) were analyzed to characterize its urinary concentration. Bentazone was detected in all the source and treated water samples. Its concentrations in the source water in July were higher than those in February (median: 17.9 ng/L vs. 2.86 ng/L) (p < 0.05). It cannot be removed efficiently (27.8-27.9%) by conventional drinking water treatment using NaClO, but it can be efficiently removed by using chlorine dioxide or ozone combined with activated carbon. Bentazone was frequently detected (detection frequency: 96.3%) in 160 tap water samples (underwent conventional treatment) (median: 1.95 ng/L, range: <0.02-47.0 ng/L), while it was not detectable in tap water samples that underwent ozone combined with activated carbon. Seasonal variations were found, with the lowest median concentration (ng/L) in April (0.46) and the highest in July (17.6). In addition, bentazone was frequently (92.1%) detected in human urine samples (median: 0.02 ng/mL; range: < 0.01-0.11 ng/mL). The estimated daily intake of bentazone based on its median concentration in tap water (0.04 ng/kg-body weight [bw]/day) accounted for approximately 8% of that based on the median urinary concentration (0.48 ng/kg-bw/day). This is the first time to characterize its occurrence in drinking water from China and its occurrence in the urine of the general population.

Total organic halogen in two drinking water supply systems: Occurrence, variations, and relationship with trihalomethanes.

The spatiotemporal presence of overall disinfection by-products (DBPs) in two full-scale drinking water supply systems (DWSSs) were investigated using quantification of total organic halogen (TOX). The relationships of TOX with water quality parameters (especially the most regulated DBPs, trihalomethanes (THMs)) were also evaluated. The TOX levels ranged between 2.6 and 70.3 µg Cl/L and between 46.6 and 205.9 µg Cl/L in raw water and distribution water, respectively. The TOX concentration in water increased by an average of nine times after water treatment and varied slightly during distribution, suggesting that TOX in drinking water was mainly formed during chlorination disinfection rather than distribution. No clear seasonality in TOX level was observed. Positive correlations were found between raw water dissolved organic carbon (DOC) with an increase in TOX in treated water and between DOC level with TOX content in distributed water, emphasizing a key role of organics in TOX formation. Chloroform (TCM) was the dominant THM, followed by bromodichloromethane (BDCM) in the drinking water, and the levels of the other two measured THMs (dibromochloromethane and bromoform) were negligible. THM2 (sum of TCM and BDCM) made up average of 18% of the TOX, and was weakly correlated with TOX content (rs = 0.321; P < 0.05), implying that THM is not a suitable surrogate measure for TOX in drinking water. This study provides basic data on the occurrence and variation of TOX within conventional DWSSs and highlights the importance of using TOX measurements to obtain more accurate information about DBP occurrence, for exposure assessment and regulatory determination.

The Advances of Neutrophil-Derived Effective Drug Delivery Systems: A Key Review of Managing Tumors and Inflammation.

The chimeric trait of recruitment by inflammatory signals endows neutrophils with the functionality of migrating to inflamed tissues, which can be utilized to tailor novel drug delivery systems. In this review, we introduce a mechanism of neutrophil-derived drug delivery systems recruited into inflamed sites and provide insight into tumors and inflammation therapy. In particular, the advantages of neutrophils-their endogenous-derived neutrophil membrane, exosomes as drug carriers for augmented targeting, prolonged circulation, and improved biostability-were concluded. Subsequently, the latest application in the treatment of tumors and inflammation was elaborated upon, followed by a discussion of the future prospects to neutrophil-derived delivery systems. This promising system will provide new therapeutic avenues for the treatment of inflammation and tumors.

Albumin-Based LL37 Peptide Nanoparticles as a Sustained Release System against Pseudomonas aeruginosa Lung Infection.

Pseudomonas aeruginosa (PA) has emerged as a pressing challenge to pulmonary infection and lung damage. The LL37 peptide is an efficient antimicrobial agent against PA strains, but its application is limited because of fast clearance in vivo, biosafety concerns, and low bioavailability. Thus, an albumin-based nanodrug delivery system with reduction sensitivity was developed by forming intermolecular disulfide bonds to increase in vivo LL37 performance against PA. Cationic LL37 can be efficiently encapsulated via electrostatic interactions to exert improved antimicrobial effects. The LL37 peptide exhibits greater than 48 h of sustained released from LL37 peptide nanoparticles (LL37 PNP), and prolonged antimicrobial effects were noted as the incubation time increased. Levels of inflammatory cytokines secreted by peritoneal macrophages, including TNF-α and IL-6, were reduced significantly after LL37 PNP treatment following PA stimulation, indicating that LL37 PNP inhibits PA growth and exerts anti-inflammatory effects in vitro. In a murine model of acute PA lung infection, LL37 PNP significantly reduced TNF-α and IL-1ß expression and alleviated lung damage. The accelerated clearance of PA indicates that LL37 PNP could improve PA lung infection and the subsequent inflammation response more efficiently compared with free LL37 peptide. In conclusion, this excellent biocompatible LL37 delivery strategy may serve as an alternative approach for the application of new types of clinical treatment in future.

Urinary concentrations of acetaminophen in young children in central and south China: Repeated measurements and associations with 8-hydroxy-guanosine and 8-hydroxy-2'-deoxyguanosine.

Acetaminophen (AAP) is the most widely used over-the-counter analgesic in the world; it is also a metabolite of industrial chemical aniline. It may predispose individuals to oxidative stress. However, the exposure profile of AAP in the general population in China and the associations between AAP and oxidative stress biomarkers have scarcely been investigated. In this study, we determined the urinary concentrations of AAP and evaluated its associations with 8-hydroxy-guanosine (8-OHG) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), the most widely used biomarkers of nucleoside oxidation affecting RNA and DNA, in 393 urine samples collected from 131 healthy children (0-6.6 y) on three consecutive days from Wuhan, central China, and Shenzhen, south China. AAP was found in all urine samples, suggesting that exposure to AAP was ubiquitous in young children in central and south China. The median concentration of specific gravity (SG)-adjusted AAP was 9.21 ng/mL (range: 1.11-1 453 ng/mL). Good inter-day reproducibility was observed for SG-adjusted AAP concentrations (intraclass correlation coefficient, 0.75). The SG-adjusted urinary 8-OHdG and 8-OHG concentrations were positively correlated with AAP (ß = 0.08; 95% confidence interval [95% CI]: 0.02-0.13, and ß = 0.10; 95% CI: 0.04-0.15, respectively). The data indicated that AAP exposure might be associated with oxidative DNA and RNA damage in the general population with unintentional exposure. To our knowledge, this is the first report of AAP exposure in young healthy children in central and south China. This is also the first study to evaluate the inter-day variations in urinary AAP concentrations and to explore the associations between AAP exposure and oxidative stress biomarkers in the general population.

A follow-up study shows that recovered patients with re-positive PCR test in Wuhan may not be infectious.

BACKGROUND: Previous studies showed that recovered coronavirus disease 2019 (COVID-19) patients can have a subsequent positive polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after they are discharged from the hospital. Understanding the epidemiological characteristics of recovered COVID-19 patients who have a re-positive test is vital for preventing a second wave of COVID-19. METHODS: This retrospective study analyzed the epidemiological and clinical features of 20,280 COVID-19 patients from multiple centers in Wuhan who had a positive PCR test between December 31, 2019, and August 4, 2020. The RT-PCR test results for 4079 individuals who had close contact with the re-positive cases were also obtained. RESULTS: In total, 2466 (12.16%) of the 20,280 patients had a re-positive SARS-CoV-2 PCR test after they were discharged from the hospital, and 4079 individuals had close contact with members of this patient group. All of these 4079 individuals had a negative SARS-CoV-2 PCR test. CONCLUSIONS: This retrospective study in Wuhan analyzed the basic characteristics of recovered COVID-19 patients with re-positive PCR test and found that these cases may not be infectious.

Household transmission of SARS-CoV-2 and risk factors for susceptibility and infectivity in Wuhan: a retrospective observational study.

BACKGROUND: Wuhan was the first epicentre of COVID-19 in the world, accounting for 80% of cases in China during the first wave. We aimed to assess household transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and risk factors associated with infectivity and susceptibility to infection in Wuhan. METHODS: This retrospective cohort study included the households of all laboratory-confirmed or clinically confirmed COVID-19 cases and laboratory-confirmed asymptomatic SARS-CoV-2 infections identified by the Wuhan Center for Disease Control and Prevention between Dec 2, 2019, and April 18, 2020. We defined households as groups of family members and close relatives who did not necessarily live at the same address and considered households that shared common contacts as epidemiologically linked. We used a statistical transmission model to estimate household secondary attack rates and to quantify risk factors associated with infectivity and susceptibility to infection, accounting for individual-level exposure history. We assessed how intervention policies affected the household reproductive number, defined as the mean number of household contacts a case can infect. FINDINGS: 27 101 households with 29 578 primary cases and 57 581 household contacts were identified. The secondary attack rate estimated with the transmission model was 15·6% (95% CI 15·2-16·0), assuming a mean incubation period of 5 days and a maximum infectious period of 22 days. Individuals aged 60 years or older were at a higher risk of infection with SARS-CoV-2 than all other age groups. Infants aged 0-1 years were significantly more likely to be infected than children aged 2-5 years (odds ratio [OR] 2·20, 95% CI 1·40-3·44) and children aged 6-12 years (1·53, 1·01-2·34). Given the same exposure time, children and adolescents younger than 20 years of age were more likely to infect others than were adults aged 60 years or older (1·58, 1·28-1·95). Asymptomatic individuals were much less likely to infect others than were symptomatic cases (0·21, 0·14-0·31). Symptomatic cases were more likely to infect others before symptom onset than after (1·42, 1·30-1·55). After mass isolation of cases, quarantine of household contacts, and restriction of movement policies were implemented, household reproductive numbers declined by 52% among primary cases (from 0·25 [95% CI 0·24-0·26] to 0·12 [0·10-0·13]) and by 63% among secondary cases (from 0·17 [0·16-0·18] to 0·063 [0·057-0·070]). INTERPRETATION: Within households, children and adolescents were less susceptible to SARS-CoV-2 infection but were more infectious than older individuals. Presymptomatic cases were more infectious and individuals with asymptomatic infection less infectious than symptomatic cases. These findings have implications for devising interventions for blocking household transmission of SARS-CoV-2, such as timely vaccination of eligible children once resources become available. FUNDING: National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities, US National Institutes of Health, and US National Science Foundation.