Radiographic features of COVID-19 based on an initial cohort of 96 patients in Singapore

INTRODUCTIONChest radiographs (CXRs) are widely used for the screening and management of COVID-19. This article describes the radiographic features of COVID-19 based on an initial national cohort of patients.METHODSThis is a retrospective review of swab-positive patients with COVID-19 who were admitted to four different hospitals in Singapore between 22 January and 9 March 2020. Initial and follow-up CXRs were reviewed by three experienced radiologists to identify the predominant pattern and distribution of lung parenchymal abnormalities.RESULTSIn total, 347 CXRs of 96 patients were reviewed. Initial CXRs were abnormal in 41 (42.7%) out of 96 patients. The mean time from onset of symptoms to CXR abnormality was 5.3 ± 4.7 days. The predominant pattern of lung abnormality was ground-glass opacity on initial CXRs (51.2%) and consolidation on follow-up CXRs (51.0%). Multifocal bilateral abnormalities in mixed central and peripheral distribution were observed in 63.4% and 59.2% of abnormal initial and follow-up CXRs, respectively. The lower zones were involved in 90.2% of initial CXRs and 93.9% of follow-up CXRs.CONCLUSIONIn a cohort of swab-positive patients, including those identified from contact tracing, we found a lower incidence of CXR abnormalities than was previously reported. The most common pattern was ground-glass opacity or consolidation, but mixed central and peripheral involvement was more common than peripheral involvement alone.     

Prediagnostic blood levels of organochlorines and risk of non-Hodgkin lymphoma in three prospective cohorts in China and Singapore

Specific organochlorines (OCs) have been associated with non-Hodgkin lymphoma (NHL) with varying degrees of evidence. These associations have not been evaluated in Asia, where the high exposure and historical environmental contamination of certain OC pesticides (e.g., dichlorodiphenyltrichloroethane [DDT], hexachlorocyclohexane [HCH]) are different from Western populations. We evaluated NHL risk and prediagnostic blood levels of OC pesticides/metabolites and polychlorinated biphenyl congeners in a case–control study of 167 NHL cases and 167 controls nested within three prospective cohorts in Shanghai and Singapore. Conditional logistic regression was used to analyze lipid-adjusted OC levels and NHL risk. Median levels of p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE), the primary DDT metabolite, and β-HCH were up to 12 and 65 times higher, respectively, in samples from the Asian cohorts compared to several cohorts in the United States and Norway. An increased risk of NHL was observed among those with higher β-HCH levels both overall (3rd vs. 1st tertile OR = 1.8, 95%CI = 1.0–3.2; p_trend = 0.049) and after excluding cases diagnosed within 2 years of blood collection (3rd vs. 1st tertile OR = 2.0, 95%CI = 1.1–3.9; p_trend = 0.03), and the association was highly consistent across the three cohorts. No significant associations were observed for other OCs, including p,p′-DDE. Our findings provide support for an association between β-HCH blood levels and NHL risk. This is a concern because substantial quantities of persistent, toxic residues of HCH are present in the environment worldwide. Although there is some evidence that DDT is associated with NHL, our findings for p,p′-DDE do not support an association.     

Bacteria-phagocyte interactions: Fusobacterium-induced secretion of a neutrophil self-regulatory factor

Direct interaction between Fusobacterium nucleatum and human neutrophils resulted in the secretion of a neutrophil self-regulatory factor(s). The secretion of this factor was bacteria specific, and depended on the integrity of the bacteria cell surface. Factor secretion occurred within 15 min of bacteria--neutrophil interaction. Pre-treatment of neutrophils with cytochalasin B but not sodium fluoride inhibited factor secretion. The factor was sensitive to trypsin and heat treatment. Ultrafiltration experiments showed that it has a molecular weight between 10,000 and 30,000 daltons. Its biologic role may be that of a molecular mediator for the recruitment of resting neutrophils so as to amplify the immunological and inflammatory response.     

人胎盘源贴壁细胞支持脐血CD34+细胞体外扩增

从胎盘中分离培养人胎盘源贴壁细胞 (humanplacentaderivedadherentcells,hPDAC) ,研究其对脐血CD34+细胞体外扩增作用。以酶消化法自人胎盘组织中分离培养hPDAC ,并以流式细胞术对其进行鉴定。进一步 ,采用免疫磁珠法分离人脐血CD34+细胞 ,建立以hPDAC为滋养层的CD34+细胞体外扩增培养体系 ,并与无滋养层的液体培养体系相比 ,观察不同培养体系对有核细胞总数、CFC及CD34+细胞百分率的影响。结果表明 ,人胎盘组织中可分离培养出hPDAC ,并证实其为混合性细胞群体 ,主要含有间充质细胞。以hPDAC为滋养层的共培养体系较无滋养层液体培养体系对有核细胞总数、CFC及CD34+细胞均具有明显的扩增效应 ,其中以SCF +IL 3+IL 6 +FL +hPDAC组扩增效果最强 ,分别扩增了 ( 12 6 .0± 6 .7)倍 ,( 4 9.8± 1.7)倍和 ( 8.3± 1.6 5 )倍。上述结果提示 ,hPDAC具有体外支持造血作用 ,并提供了一与脐血CD34+细胞体外扩增相适应的新滋养层。     

Suppression of neutrophil and lymphoproliferative responses in vitro by itraconazole but not fluconazole

Itraconazole and fluconazole are triazole compounds recently licensed for the therapy of systemic fungal infections. At 10 micrograms/ml concentrations, itraconazole was found to suppress neutrophil chemotaxis, random movement, deoxyglucose uptake and hexose-monophosphate shunt activity to the same extent as ketoconazole, an older generation azole antifungal. Itraconazole was also found to suppress mitogen-induced lymphocyte transformation to the same extent as ketoconazole at concentrations as low as 1 microgram/ml. By contrast, significant inhibition of both neutrophil and lymphocyte functions was not observed with fluconazole at concentrations as high as 50 micrograms/ml. These results suggest that fluconazole may be less immunotoxic than itraconazole, and may be more suitable for use in immunocompromised patients.     

Effect of solvents in extracting polyphenols and antioxidants of selected raw vegetables

Thirty-seven raw vegetables were extracted using four solvent systems: 70% acetone, 70% ethanol, 70% methanol, and distilled water. The extracts were tested for their total phenolic content, total flavonoid content and antioxidant activities (using diphenylpicryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays). The results revealed the effect of different extracting solvents in altering the quantitative analyses of all vegetables and 70% acetone was identified as the most efficient solvent for extracting polyphenolic antioxidants from the vegetables. The highest total phenolic content and total flavonoid content were obtained from 70% acetone extract of Portulaca oleracea (138.2 ± 2.1 mg GAE/g dw basis) and 70% methanol extract of Cosmos caudatus (27.7 ± 1.0 mg QE/g dw basis), respectively. The 70% acetone extract of Etlingera elatior with moderate amount of total phenolic content exhibited the highest antioxidant activity in both assays. The correlation analyses within 37 different extracts of each solvent extraction demonstrated weak to moderate relationships between all the studied parameters. The highest r value of 0.7139 (p < 0.001) was determined between total phenolic contents and FRAP values of the 70% methanol extracts. Meanwhile, a wide range of correlation coefficients was derived from correlation analyses within four different extracts of each vegetable, with the highest relationship between total phenolic contents and FRAP values for the extracts of Coriandrum sativum (r = 0.9998, p < 0.001).