Evaluación de una prueba de reacción en cadena de la polimerasa múltiplex anidada para la detección de HTLV-1

El Perú es un área endémica al virus linfotrópico T humano tipo 1 (HTLV-1) y para su confirmación diagnóstica se usa pruebas serológicas que pueden dar resultados no concluyentes. Objetivos: evaluar una prueba de PCR múltiplex anidada para diagnosticar el HTLV-1. Métodos: la validación de la PCR se realizó con primers dirigidos a las regiones Pol y LTR del HTLV-1. Se empleó el gen ß-globina como control endógeno interno y el límite de detección se evaluó con células MT2. Los parámetros de precisión diagnóstica se evaluaron frente a 95 muestras sanguíneas de Referencia. Resultados: la prueba evaluada obtuvo un límite de detección de 0,5 ng/µL de ADN sensibilidad diagnóstica=97,1%, especificidad diagnóstica y analítica=100%, vpn=97,2%, vpp, repetibilidad y reproducibilidad=100%; Kappa, Índice Youden=0,97. Conclusiones: la prueba evaluada presenta un alto rendimiento diagnóstico y debido a su bajo costo se recomienda su implementación en el algoritmo del diagnóstico de HTLV-1 en Perú.

Peru is an endemic area for human T-lymphotropic virus type 1 (HTLV-1) and for its diagnostic confirmation serological tests are used, which can give inconclusive results. Objectives: to evaluate a nested multiplex PCR test to diagnose HTLV-1. Methods: PCR validation was performed with primers targeting the Pol and LTR regions of HTLV-1. The ß-globin gene was used as an internal endogenous control and the detection limit was evaluated with MT2 cells. Diagnostic accuracy parameters were evaluated against 95 Reference blood samples. Results: the evaluated test obtained a detection limit of 0.5 ng/µL of DNA; diagnostic sensitivity=97.1%, diagnostic and analytical specificity=100%, vpn=97.2%, vpp, repeatability and reproducibility=100%; Kappa, Youden Index=0.97. Conclusions: the evaluated test has a high diagnostic performance and due to its low cost, its implementation in the HTLV-1 diagnosis algorithm in Peru is recommended.

Incidence and factors associated with pulmonary embolism among RT-PCR confirmed Covid-19 patients with upfront CT pulmonary angiography in Ethiopia: A nested case-control study

Introduction: Pulmonary embolism is one of the complications of COVID-19, with reported incidence ranging from 3 to 33 % in non-ICU patients to as high as 40% among ICU patients. Since the clinical presentations of COVID-19 and Pulmonary embolism overlap, it is difficult to differentiate between these cases. This study aimed to assess the incidence of pulmonary embolism and associated factors among confirmed Covid-19 Patients in Ethiopia. Methods: A nested case control study was conducted among 131 patients with COVID-19 (40 COVID-19 patients with Pulmonary embolism and 91 COVID-19 patients with no PE) who were on follow up from May, 2021 to May, 2022. Data was summarized using frequencies with percentages. A chi-square test/ Fisher's exact test was run to determine the presence of a significant difference between the exposure variables and the development of PE. To identify factors associated with the development of Pulmonary embolism, a multivariable Binary Logistic Regression model with sensitivity analysis was run. Results: The incidence of PE was 30.5% (95% CI, 22.9% - 37.4%) in the cohort of patients for whom upfront CTPA was performed. The Chi-square/ Fisher's exact test results showed a significantly higher proportion of patients with PE tend to present with shortness of breath, chest pain and anosmia/ageusia than those with no PE. However, in a subsequent regression analysis, only chest pain was found to be significantly associated with the development of PE in COVID-19 patients (AOR= 3.24, 95% CI= 1.10, 9.54, p-value=0.033). Conclusion: The incidence of PE among COVID-19 patients was found to be relatively lower than reports from other countries. Having chest pain was found to be a significant factor that indicates the development of PE, implying that in a setting where performing upfront CTPA is not practical, detailed symptom inquiry could serve as an important clinical criteria.

Occult hepatitis B virus infection in patients with chronic liver disease of different etiology in a Brazilian referral center: comparison of two different hepatitis B virus deoxyribonucleic acid amplification protocols: a cross-sectional study

ABSTRACT BACKGROUND: Occult hepatitis B virus infection (OBI) is defined as the presence of hepatitis B virus (HBV) deoxyribonucleic acid (DNA) in the liver of individuals with undetectable hepatitis B virus surface antigen (HBsAg) in the serum. The actual prevalence of OBI and its clinical relevance are not yet fully understood. OBJECTIVE: To evaluate the prevalence of HBV DNA in liver biopsies of HBsAg-negative patients with chronic liver disease of different etiologies in a referral center in Brazil and compare two different HBV DNA amplification protocols to detect HBV. DESIGN AND SETTING: This cross-sectional observational study was conducted at the Liver Outpatient Clinic, Hospital das Clínicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil, between January 2016 and December 2019. METHODS: HBV DNA was investigated in 104 liver biopsy samples from individuals with chronic liver disease of different etiologies, in whom HBsAg was undetectable in serum by nested-polymerase chain reaction (nested-PCR), using two different protocols. RESULTS: OBI, diagnosed by detecting HBV DNA using both protocols, was detected in 6.7% of the 104 individuals investigated. Both protocols showed a good reliability. CONCLUSION: In addition to the differences in the prevalence of HBV infection in different regions, variations in the polymerase chain reaction technique used for HBV DNA amplification may be responsible for the large variations in the prevalence of OBI identified in different studies. There is a need for better standardization of the diagnostic methods used to diagnose this entity.

Cross-genera amplification and identification of Colpodella sp. with Cryptosporidium primers in fecal samples of zoo felids from northeast China / Amplificação cruzada de gêneros e identificação de Colpodella sp. com iniciadores de Cryptosporidium em amostras fecais de zoofilia do nordeste da China

Abstract The protozoans include many intracellular human pathogens. Accurate detection of these pathogens is necessary to treat the diseases. In clinical epidemiology, molecular identification of protozoan is considered a more reliable and rapid method for identification than microscopy. Among these protozoans, Cryptosporidium considered being one of the important water-borne zoonotic pathogens and a major cause of a diarrheal disease named cryptosporidiosis in humans, domestic animals, and wild animals. This study was aimed to identify Cryptosporidium in zoo felids (N= 56) belonging to different zoo of China, but accidentlly Colpodella was encountered in the zoo felids sample and phylogenetic data confirmed this unexpected amplification from fecal samples using two-step nested-PCR. Phylogenetic analysis revealed the fact about the specific primers used previously by many researchers and cross-genera amplification. We came to know that genetically sequenced amplicon gives more accurate identification of species. This study suggests more investigation on Colpodella which has been neglected previously but gains the attention of researchers after identified from humans and animals and has been known to correlate with neurological symptoms in patients.

Resumo Os protozoários incluem muitos patógenos humanos intracelulares. A detecção acurada desses patógenos é necessária para tratar as doenças. Na epidemiologia clínica, a identificação molecular de protozoários é considerada o método de identificação mais confiável e rápido do que a microscopia. Entre esses protozoários, o Cryptosporidium é considerado um dos importantes patógenos zoonóticos transmitidos pela água e uma das principais causas de uma doença diarreica denominada criptosporidiose em humanos, animais domésticos e selvagens. Este estudo teve como objetivo identificar Cryptosporidium em zoofelídeos (N = 56) pertencentes a diferentes zoológicos da China, mas acidentalmente Colpodella foi encontrada na amostra de zoofelídeos e os dados filogenéticos confirmaram essa amplificação inesperada de amostras fecais usando nested-PCR em duas etapas. A análise filogenética revelou o fato sobre os primers específicos usados ​​anteriormente por muitos pesquisadores e a amplificação entre gêneros. Ficamos sabendo que o amplicon sequenciado geneticamente fornece uma identificação mais acurada das espécies. Este estudo sugere mais investigação sobre Colpodella, que foi negligenciada anteriormente, mas ganha a atenção dos pesquisadores depois de identificada em humanos e animais e é conhecida por se correlacionar com sintomas neurológicos em pacientes.

A nested-PCR for detection and identification of Brucella vaccine A19 strain / 中华地方病学杂志

Objective:A nested-PCR assay is developed to detect and identify the genomic DNA of Brucella vaccine A19 strain. Methods:The whole genomic sequences of Brucella vaccine A19 strain and other Brucella spp. strains were compared and analyzed. The primers were designed by nucleotide difference sites. The nested-PCR assay was established to detect and identify Brucella vaccine A19 strain. The genomic DNA of Brucella vaccine A19 strain was extracted and diluted. The diluted template DNA was tested for sensitivity of using nested-PCR assay. And the specificity of nested-PCR assay was tested for the genomic DNA of other Brucella spp. strains and non- Brucella spp. strains. Results:The minimum detection limit of the nested-PCR assay was 3.43 fg. The nested-PCR assay established for amplification of Brucella vaccine A19 strain showed 246 bp electrophoresis bands, while other Brucella spp. strains showed 314 bp electrophoresis bands, and non- Brucella spp. strains did not produce electrophoresis bands. Conclusions:The nested-PCR assay established has the characteristics of high sensitivity and specificity. It can be detected when there is one copy of Brucella vaccine A19 strain genomic DNA in the reaction system. This method is particularly suitable for the detection and identification of trace genomic DNA of Brucella vaccine A19 strain in sample.

Risk factors for hemodynamically significant patent ductus arteriosus in preterm infants requiring surgical ligation: a nested case-control study / 中华实用儿科临床杂志

Objective:To analyze the risk factors for premature infants with hemodynamically significant patent ductus arteriosus (hs-PDA) requiring surgical treatment, and to explore the indications for surgical treatment in premature infants with hs-PDA.Methods:A nested case-control study was conducted.The data of premature infants with gestational age<30 weeks who were diagnosed with hs-PDA in the Neonatal Intensive Care Unit of Peking Union Medical College Hospital from January 2007 to May 2020 were analyzed retrospectively.The hs-PDA patients treated surgically were included in the operation group.The hs-PDA patients of the same gestational age and gender who were not treated surgically were taken as the control group.The ratio of the case number between the operation and control groups was 1∶2.The clinical data during pregnancy, at birth and after birth of premature infants were compared between the 2 groups.The measurement data were tested by the independent sample t test or Mann- Whitney U test.The classification and enumeration data were compared by the Fisher′ s exact probability method.The risk factors for premature infants with hs-PDA requiring surgical treatment were analyzed by the conditional Logistic regression method. Results:A total of 182 premature infants with hs-PDA were enrolled in the study, including 10 in the operation group and 20 in the control group.The patients underwent PDA ligation 30.5(22.7, 37.0) d after birth, and the median preo-perative invasive ventilation duration was 9.7(17.5, 27.2) d. Compared with the control group(20 cases), the preterm infants in the operation group had a lower birth weight [(891.5±118.0) g vs.(1 054.4±230.2) g, t=2.091], a wider arterial duct diameter [3.2(2.8, 4.0) mm vs.2.0(2.0, 3.0) mm, Z=-3.300], and longer invasive ventilation duration [25.0(18.7, 38.2) d vs.3.0(1.0, 7.5) d, Z=-3.688]. Besides, the operation group applied the pulmonary surfactant for more times [2(1, 3) times vs.1(1, 2) times, Z=-2.440], and inhaled a higher concentration of oxygen on the 14 th day after birth [29(25, 36)% vs.21(21, 29)%, Z=-2.358] than the control group.Moreover, compared with the control group, the operation group took longer to achieve adequate enteral feeding [48.2(51.5, 63.5) d vs.42.5(23.5, 48.0) d, Z=2.789], and gained a higher maximum vasoactive inotropic score (VIS) [3.0(0, 3.5) points vs.0(0, 0) points, Z=-2.630]. The difference in all the above-mentioned indicators between the 2 groups was statistically significant (all P<0.05). Univariate Logistic regression analysis showed that the arterial duct diameter, application times of the pulmonary surfactant, the maximum VIS score, and the time taken to achieve sufficient enteral feeding were all related to the need for surgical treatment of hs-PDA in the operation group (all P<0.05). Multivariate Logistic regression analysis revealed that the invasive ventilation duration ( OR=0.747, 95% CI: 0.560-0.998, P=0.048) was an independent risk factor for hs-PDA premature infants requiring surgical treatment. Conclusions:The factors related to the need for surgical treatment in preterm infants with hs-PDA include a wide arterial duct diameter, multiple applications of the pulmonary surfactant, a high concentration of inhaled oxygen on the 14 th day, and the long time to achieve sufficient enteral feeding.The independent risk factor for the surgical treatment in hs-PDA children is the long invasive ventilation duration.

Case-control Design and Real-world Database Studies / 薬剤疫学

A case-control design is one of common study designs in epidemiology. A case with an outcome event of interest is identified and a corresponding control without an outcome event is sampled from a study base, which give rise to the cases. Distribution of a past exposure to an agent of interest before the timing of sampling is compared between a case group and a control group, to yield an odds ratio of exposure as a risk index. A cohort design is usually costly because it requires a large sample size and a long-term follow-up period to power a study especially to detect rare outcome events. In contrast, a traditional case-control design brings efficiency in resource and time to study the association of an exposure and an outcome event by reducing a sample size to study an exposure and covariates after sampling compared with a traditional cohort design. This review article discusses whether a case-control sampling strategy in healthcare database studies, where all the data for the study variables necessary for analysis already exist and are readily available, remains advantageous over a cohort design from the viewpoints of study cost and utility.

Early prenatal exposure to air pollutants and congenital heart disease: a nested case-control study

BACKGROUND@#Congenital heart disease (CHD) is one of the most common congenital malformations in humans. Inconsistent results emerged in the existed studies on associations between air pollution and congenital heart disease. The purpose of this study was to evaluate the association of gestational exposure to air pollutants with congenital heart disease, and to explore the critical exposure windows for congenital heart disease.@*METHODS@#The nested case-control study collected birth records and the following health data in Tianjin Women and Children's Health Center, China. All of the cases of congenital heart disease from 2013 to 2015 were selected matching five healthy controls for each case. Inverse distance weighting was used to estimate individual exposure based on daily air pollution data. Furthermore, the conditional logistic regression with distributed lag non-linear model was performed to identify the association between gestational exposure to air pollution and congenital heart disease.@*RESULTS@#A total of 8,748 mother-infant pairs were entered into the analysis, of which 1,458 infants suffered from congenital heart disease. For each 10 µg/m3 increase of gestational exposure to PM2.5, the ORs (95% confidence interval, 95%CI) ranged from 1.008 (1.001-1.016) to 1.013 (1.001-1.024) during the 1st-2nd gestation weeks. Similar weak but increased risks of congenital heart disease were associated with O3 exposure during the 1st week and SO2 exposure during 6th-7th weeks in the first trimester, while no significant findings for other air pollutants.@*CONCLUSIONS@#This study highlighted that gestational exposure to PM2.5, O3, and SO2 had lag effects on congenital heart disease. Our results support potential benefits for pregnancy women to the mitigation of air pollution exposure in the early stage, especially when a critical exposure time window of air pollutants may precede heart development.

Cross-genera amplification and identification of Colpodella sp. with Cryptosporidium primers in fecal samples of zoo felids from northeast China / Amplificação cruzada de gêneros e identificação de Colpodella sp. com iniciadores de Cryptosporidium em amostras fecais de zoofilia do nordeste da China

The protozoans include many intracellular human pathogens. Accurate detection of these pathogens is necessary to treat the diseases. In clinical epidemiology, molecular identification of protozoan is considered a more reliable and rapid method for identification than microscopy. Among these protozoans, Cryptosporidium considered being one of the important water-borne zoonotic pathogens and a major cause of a diarrheal disease named cryptosporidiosis in humans, domestic animals, and wild animals. This study was aimed to identify Cryptosporidium in zoo felids (N= 56) belonging to different zoo of China, but accidentlly Colpodella was encountered in the zoo felids sample and phylogenetic data confirmed this unexpected amplification from fecal samples using two-step nested-PCR. Phylogenetic analysis revealed the fact about the specific primers used previously by many researchers and cross-genera amplification. We came to know that genetically sequenced amplicon gives more accurate identification of species. This study suggests more investigation on Colpodella which has been neglected previously but gains the attention of researchers after identified from humans and animals and has been known to correlate with neurological symptoms in patients.

Os protozoários incluem muitos patógenos humanos intracelulares. A detecção acurada desses patógenos é necessária para tratar as doenças. Na epidemiologia clínica, a identificação molecular de protozoários é considerada o método de identificação mais confiável e rápido do que a microscopia. Entre esses protozoários, o Cryptosporidium é considerado um dos importantes patógenos zoonóticos transmitidos pela água e uma das principais causas de uma doença diarreica denominada criptosporidiose em humanos, animais domésticos e selvagens. Este estudo teve como objetivo identificar Cryptosporidium em zoofelídeos (N = 56) pertencentes a diferentes zoológicos da China, mas acidentalmente Colpodella foi encontrada na amostra de zoofelídeos e os dados filogenéticos confirmaram essa amplificação inesperada de amostras fecais usando nested-PCR em duas etapas. A análise filogenética revelou o fato sobre os primers específicos usados anteriormente por muitos pesquisadores e a amplificação entre gêneros. Ficamos sabendo que o amplicon sequenciado geneticamente fornece uma identificação mais acurada das espécies. Este estudo sugere mais investigação sobre Colpodella, que foi negligenciada anteriormente, mas ganha a atenção dos pesquisadores depois de identificada em humanos e animais e é conhecida por se correlacionar com sintomas neurológicos em pacientes.

Cross-genera amplification and identification of Colpodella sp. with Cryptosporidium primers in fecal samples of zoo felids from northeast China

Abstract The protozoans include many intracellular human pathogens. Accurate detection of these pathogens is necessary to treat the diseases. In clinical epidemiology, molecular identification of protozoan is considered a more reliable and rapid method for identification than microscopy. Among these protozoans, Cryptosporidium considered being one of the important water-borne zoonotic pathogens and a major cause of a diarrheal disease named cryptosporidiosis in humans, domestic animals, and wild animals. This study was aimed to identify Cryptosporidium in zoo felids (N= 56) belonging to different zoo of China, but accidentlly Colpodella was encountered in the zoo felids sample and phylogenetic data confirmed this unexpected amplification from fecal samples using two-step nested-PCR. Phylogenetic analysis revealed the fact about the specific primers used previously by many researchers and cross-genera amplification. We came to know that genetically sequenced amplicon gives more accurate identification of species. This study suggests more investigation on Colpodella which has been neglected previously but gains the attention of researchers after identified from humans and animals and has been known to correlate with neurological symptoms in patients.

Resumo Os protozoários incluem muitos patógenos humanos intracelulares. A detecção acurada desses patógenos é necessária para tratar as doenças. Na epidemiologia clínica, a identificação molecular de protozoários é considerada o método de identificação mais confiável e rápido do que a microscopia. Entre esses protozoários, o Cryptosporidium é considerado um dos importantes patógenos zoonóticos transmitidos pela água e uma das principais causas de uma doença diarreica denominada criptosporidiose em humanos, animais domésticos e selvagens. Este estudo teve como objetivo identificar Cryptosporidium em zoofelídeos (N = 56) pertencentes a diferentes zoológicos da China, mas acidentalmente Colpodella foi encontrada na amostra de zoofelídeos e os dados filogenéticos confirmaram essa amplificação inesperada de amostras fecais usando nested-PCR em duas etapas. A análise filogenética revelou o fato sobre os primers específicos usados anteriormente por muitos pesquisadores e a amplificação entre gêneros. Ficamos sabendo que o amplicon sequenciado geneticamente fornece uma identificação mais acurada das espécies. Este estudo sugere mais investigação sobre Colpodella, que foi negligenciada anteriormente, mas ganha a atenção dos pesquisadores depois de identificada em humanos e animais e é conhecida por se correlacionar com sintomas neurológicos em pacientes.

A Nested Case-Control Study to Explore the Association between Immunoglobulin G N-glycans and Ischemic Stroke / 生物医学与环境科学（英文）

OBJECTIVE@#This study prospectively investigates the association between immunoglobulin G (IgG) N-glycan traits and ischemic stroke (IS) risk.@*METHODS@#A nested case-control study was conducted in the China suboptimal health cohort study, which recruited 4,313 individuals in 2013-2014. Cases were identified as patients diagnosed with IS, and controls were 1:1 matched by age and sex with cases. IgG N-glycans in baseline plasma samples were analyzed.@*RESULTS@#A total of 99 IS cases and 99 controls were included, and 24 directly measured glycan peaks (GPs) were separated from IgG N-glycans. In directly measured GPs, GP4, GP9, GP21, GP22, GP23, and GP24 were associated with the risk of IS in men after adjusting for age, waist and hip circumference, obesity, diabetes, hypertension, and dyslipidemia. Derived glycan traits representing decreased galactosylation and sialylation were associated with IS in men (FBG2S2/(FBG2 + FBG2S1 + FBG2S2): odds ratio ( OR) = 0.92, 95% confidence interval ( CI): 0.87-0.97; G1 n: OR = 0.74, 95% CI: 0.63-0.87; G0 n: OR = 1.12, 95% CI: 1.03-1.22). However, these associations were not found among women.@*CONCLUSION@#This study validated that altered IgG N-glycan traits were associated with incident IS in men, suggesting that sex discrepancies might exist in these associations.

Development and preliminary evaluation of a fluorescence RPA assay for the rapid detection of Necator americanus / 中国热带医学

@#Abstract: Objective To establish a rapid detection assay based on fluorescence recombinase polymerase amplification (RPA) targeting Necator americanus eggs, and to evaluate its efficacy, providing technical support for rapid detection of Necator americanus in fecal samples. Methods The fluorescence RPA primers and probe were designed based on the cox1 gene of Necator americanus and then screened the optimal combination to develop the assay. The genomic DNA of Necator americanus eggs was diluted to 7 concentration gradients including 100 pg/µL, 10 pg/µL, 1 pg/µL, 100 fg/µL, 10 fg/µL, 1 fg/µL, 0.1 fg/µL, to determine the detection limit of the assay. The specificity of the assay was demonstrated by detected genomic DNA from Schistosoma japonicum, Ascaris lumbricoides, Clonorchis sinensis and Fasciola hepatica. A total of 44 fecal samples were collected and DNA extraction was performed, and the modified Kato-Katz method, semi-nest PCR method, and fluorescent RPA method were simultaneously used for detection to evaluate the sensitivity and specificity. Results The established fluorescence RPA assay can specifically amplify a fragment of 194 bp of the Necator americanus cox1 gene within 20 min, with a detection limit of 10 fg/µL. There was no cross-reactivity with Schistosoma japonicum, Ascaris lumbricoides, Clonorchis sinensis, Fasciola hepatica after specificity validation. In 44 fecal samples, 27 positive samples were detected by the fluorescence RPA assay, and 26 positive samples were detected by both the Kato-Katz and the semi-nested PCR. The fluorescence curve of sample number 1 was slightly higher than the negative control in the later stage of the reaction, but did not show a similar trend to the positive control, and was therefore judged to be a suspected negative sample. Compared with the Kato-Katz method and the semi-nest PCR method, The sensitivity of the fluorescent RPA method were 100.00% and the specificity were 94.44%, and the consistency of the detection results was good (Kappa=0.953>0.75). Conclusions The assay based on the fluorescence RPA is an efficient, sensitive and specific technique for detecting Necator americanus and it can be applied for surveillance and early warning of hookworm infection.

Estudio multicéntrico de incidencia y determinantes de COVID-19 en médicos de Argentina / Multicenter study of COVID-19 incidence and determinants in Argentinian physicians

Resumen Introducción: La información sobre COVID en médicos es limitada. Su conocimiento permitiría implementar acciones para reducir su impacto. El objetivo general fue determinar la incidencia de infección por SARS-CoV-2 en médicos de instituciones de salud de Argentina, sus características y factores aso ciados. Materiales y Métodos: Se realizó un estudio multicéntrico de cohorte prospectiva/retrospectiva con estudio de casos-controles anidado. Se incluyeron médicos activos al inicio de la pandemia no exceptuados por riesgo. Se estimó incidencia de casos confirmados. Se compararon factores asociados en casos y controles y se creó un modelo de regresión logística con las variables significativas del análisis bivariado. Resultados: Se incluyeron 343 médicos con COVID de 8 centros. La incidencia de la enfermedad fue de 12.1% y la de ausentismo global relacionado a COVID, de 34.1%. El 70% de los contactos estrechos fueron laborales. En el análisis multivariado de casos y controles, la residencia en la Ciudad Autónoma de Buenos Aires (OR 0.19, p = 0.01), el trabajo en áreas de alto riesgo (OR 0.22, p = 0.01) y vehículo individual (OR 0.34, p = 0.03) redujeron el riesgo de COVID. El odds de enfermar aumentó 4.6 veces (p = 0.02) por cada aislamiento por contacto estrecho. Discusión: El riesgo de enfermar aumentó considerablemente con cada aislamiento por contacto estrecho. La residencia en Ciudad Autónoma, el traslado en vehículo individual y el trabajo en áreas de alto riesgo lo redujeron. Dada la alta frecuencia de contactos estrechos en el ámbito laboral recomendamos reforzar las medidas de prevención en áreas de descanso y no COVID.

Abstract Background: Information about COVID infection in physicians is limited. This knowledge would allow the implementation of actions to reduce its impact. The objective was determining the incidence of SARS-CoV-2 infection in physicians from health institutions in Argentina, its characteristics, and associated factors. Methods: We conducted a multicenter prospective / retrospective cohort study with nested case-control study. Physicians active at the beginning of the pandemic were included, those on leave due to risk factors were excluded. The incidence of confirmed cases was estimated. We conducted bivariate analyses with various factors and used those significant in a logistic regression. Results: Three hundred and forty three physicians with COVID-infection from 8 centers were included. The incidence of disease was 12.1% and that of global absenteeism related to COVID, 34.1%. Almost 70% of close contacts were work-related. In the multivariate analysis living in Autonomous City of Buenos Aires (CABA) (OR 0.19, p = 0.01), working in high-risk areas (OR 0.22, p = 0.01) and individual transportation (OR 0, 34, p = 0.03) reduced the risk of COVID. The odds of infection increased 5.6 times (p = 0.02) for each close contact isolation. Discussion: The number of close contact isolation increased considerably the risk of infection. Living in Buenos Aires City, individual transpor tation and working in high-risk areas reduced it. Given the high frequency of close contact in the workplace, we strongly recommend the reinforcement of prevention measures in rest areas and non-COVID-wards.

HBV serologic and virus characteristics of HBsAg negative and NAT non-discriminated samples from blood donors / 中国输血杂志

【Objective】 To investigate the HBV infection of TMA initially reactive but discriminatory test non-reactive samples(NDR) after the individual donation nucleic acid detection(ID-NAT)of TMA, and analyze its serological and molecular biological characteristics, so as to improve the safety of blood transfusion. 【Methods】 121 970 samples of blood donors in the center from January 1, 2021 to December 31, 2021 were routinely tested by serology and nucleic acid of ID NAT, and 21 HBsAg(-)/ NDR samples were random collected. After the plasma samples were concentrated by ultra-high speed centrifugation, the gene sequences of BCP/PC, pre-S/S and S region were amplified by Nested PCR. The S region sequence was also sequenced to analyze the viral genotype and amino acid variation. At the same time, the original TMA retest discriminatory test was adopted, and Roche MPX 2.0 was used for ID-NAT, and the samples was not virus-concentrated.NDR samples were supplemented with electrochemiluminescence for anti-HBc and anti-HBs quantitative detection. 【Results】 Of the 121 970 samples screened, 117(0.096%) were found to be HBsAg(-)/NDR samples, of which 21 samples underwent a confirmation test. Sixteen(76.2%) cases were positive for HBV DNA by TMA retest, 7(33.3%) positive for HBV DNA by Roche MPX 2.0 ID-NAT, 9(42.9%) confirmed by Nested PCR, and 8(38.1%) positive by any two methods. Test results of serological markers were as follows: 17(80.9%) positive anti-HBc and 8(38.1%) positive anti-HBs. Eight infected cases were confirmed to have occult hepatitis B infection(OBI). The gene sequence of S region was successfully amplified and sequenced in 3 cases, all of which belonged to C type. Two mutations occurred in specimen S-2, all of which were outside MHR. There were 13 mutations in sample S-6, 6 mutations outside MHR and 7 mutations inside MHR. 【Conclusion】 Nearly 40% of NDR samples can still be detected as HBV DNA positive after virus concentration. Anti-HBc has a high detection rate, and there may be a potential risk of HBV transmission. The current NAT detection sensitivity should be improved. The amino acid mutation of S gene sequence may be related to OBI formation.

A nested case-control study on association between self-reported occupational sulfur dioxide exposure and hypertension / 环境与职业医学

Background Current evidence on whether occupational sulfur dioxide (SO2) exposure affects the risk of hypertension is still limited, and the research results of the effect of environmental SO2 exposure on risk of hypertension remain inconsistent. Objective To analyze the association between self-reported occupational exposure to SO2 and the risk of hypertension, and the potential dose-response relationship between the years of exposure to SO2 and the risk of hypertension. Methods Based on the Jinchang cohort, a nested case-control study design was adopted. A total of 841 newly diagnosed hypertension patients were followed up as the case group, and the control group was selected with 1∶1 individual matching based on non-occupational factors and occupational factors, respectively. The former matching conditions included age ±2 years old, same gender, working age ±2 years, and home address in the same sub-district. The latter was limited to working in the same workshop on the basis of the former conditions. Finally, the former included 717 controls and the latter included 488 controls. A unified questionnaire was used to collect general demographic characteristics, lifestyle habits, history of diabetes, family history of hypertension, and information on occupational exposure to SO2 (self-reported history of occupational exposure to SO2 and years of exposure to SO2). Conditional logistic regression model was used to analyze the association between occupational exposure to SO2 and hypertension, and the dose-response relationship between the years of SO2 exposure and the risk of hypertension. Results In the nested case-control study matching with the non-occupational factors, the OR of hypertension in workers with self-reported occupational exposure to SO2 was 2.39 (95%CI: 1.68-3.39); while when matching with the occupational factors, the OR of hypertension in workers with self-reported occupational exposure to SO2 was 1.48 (95%CI: 1.04-2.12). The results of the dose-response relationship showed that as the SO2 exposure years increased from 1-9 years, 10-19 years, 20-29 years, and 30 years and above, in the nested case-control study matching with non-occupational factors, the ORs of hypertension were 1.85 (95%CI: 0.68-5.08), 1.46 (95%CI: 0.58-3.67), 1.64 (95%CI: 1.00-2.67), and 4.95 (95%CI: 2.63-9.31), respectively; in the nested case-control study matching with occupational factors, the ORs of hypertension were 0.98 (95%CI: 0.40-2.41), 1.84 (95%CI: 0.72-4.70), 1.37 (95%CI: 0.82-2.29), and 2.44 (95%CI: 1.37-4.35), respectively. The two dose-response relationships were positive by χ2 trend test (Ptrend<0.05). Conclusion Self-reported occupational exposure to SO2 is associated with the risk of hypertension in the study population, and the hypertension risk increases with the increase of SO2 exposure years.

Electrocardiogram signal classification algorithm of nested long short-term memory network based on focal loss function / 生物医学工程学杂志

Electrocardiogram (ECG) can visually reflect the physiological electrical activity of human heart, which is important in the field of arrhythmia detection and classification. To address the negative effect of label imbalance in ECG data on arrhythmia classification, this paper proposes a nested long short-term memory network (NLSTM) model for unbalanced ECG signal classification. The NLSTM is built to learn and memorize the temporal characteristics in complex signals, and the focal loss function is used to reduce the weights of easily identifiable samples. Then the residual attention mechanism is used to modify the assigned weights according to the importance of sample characteristic to solve the sample imbalance problem. Then the synthetic minority over-sampling technique is used to perform a simple manual oversampling process on the Massachusetts institute of technology and Beth Israel hospital arrhythmia (MIT-BIH-AR) database to further increase the classification accuracy of the model. Finally, the MIT-BIH arrhythmia database is applied to experimentally verify the above algorithms. The experimental results show that the proposed method can effectively solve the issues of imbalanced samples and unremarkable features in ECG signals, and the overall accuracy of the model reaches 98.34%. It also significantly improves the recognition and classification of minority samples and has provided a new feasible method for ECG-assisted diagnosis, which has practical application significance.

A case of severe hookworm infection / 中南大学学报(医学版)

With the improvement of sanitation, the infection rate of hookworm is greatly reduced and the severe infected case is rarely reported. Combined morphological and molecular biological examinations, a severe hookworm infection patient was diagnosed in Department of Laboratorial Examination, Quanzhou First Affiliated Hospital of Fujian Medical University. The morphological methods such as direct fecal smear microscopy, saturated brine flotation and hookworm larvae culture methods were used to identify the eggs and larvae from stool samples of the patient. There were a large number of hookworm eggs in patient's stool samples, and the average count was 60 840 per gram by modified Kato method, which belonged to severe hookworm infection. Meanwhile, to distinguish the hookworm species, the semi-nested RT-PCR assay was employed to detect hookworm internal transcribed spacer series from eggs in patient's stool samples, and the result showed that the hookworm species was confirmed to be Necator americanus.

How to use analysis of variance correctly——an analysis of variance for the univariate quantitative data collected from the nested design / 四川精神卫生

The purpose of this paper was to introduce the nested design and its quantitative data analysis of variance and the SAS implementation. If one of the following two characteristics existed in a specific experimental study， a nested design could be considered to arrange the experiment. Firstly， there was a nested relationship between factors in natural attributes. Secondly， with professional knowledge as the basis， the impact of each factor on the quantitative observation results was divided into primary and secondary. The first feature mentioned above meant that the factors related to the subjects had the conditions for grouping and regrouping. The second feature mentioned above meant that the status of each factor was unequal. In the variance analysis of quantitative data， the calculation formulas of variable error mean square was required to use. Based on four examples and with the help of the SAS software， this paper implemented the univariate analysis of variance for the quantitative data of the nested design， and gave the detailed explanations for the output results of SAS software.

Microscopio and PCR-based detection of microsporidia spores in human stool samples

Abstract Microsporidia are obligate intracellular fungi with a remarkable ability to infect a wide range of invertebrate and vertebrate hosts. Namely, Enterocytozoon bieneusi is the most frequently microsporidia reported worldwide, and mainly associated with chronic diarrea and wasting syndrome in AIDS patients. Microscopy and PCR-based detection techniques are effective for diagnosis and identification of species and genotypes; however, these methods should be standardized in each laboratory. In this study, we performed microscopy and nested PCR techniques with PCR product sequencing to detect E. bieneusi in human stool samples. These techniques, if applied together, might prove useful for diagnosis and future epidemiological studies of intestinal microsporidiosis in Argentina.

Resumen Los microsporidios son hongos intracelulares obligados con una notable capacidad para infectar una amplia gama de hospedadores invertebrados y vertebrados. Enterocytozoon bieneusi es el microsporidio más frecuentemente reportado en todo el mundo, principalmente tricrómicaasociado con diarrea crónica y síndrome debilitante en pacientes con sida. Las técnicas dedetección basadas en microscopía y PCR son útiles para el diagnóstico y la identificación deespecies y genotipos, pero estos métodos deben estar estandarizados en cada laboratorio.En este estudio evaluamos técnicas de microscopía y PCR anidada, con secuenciación de losproductos, para detectar E. bieneusi en muestras de heces humanas. Estas técnicas, usadas con-juntamente, podrían ser útiles para su aplicación en el diagnóstico de microsporidiosis intestinaly para realizar estudios epidemiológicos de esta afección en Argentina.

Pathological, molecular and phylogenic study of fowlpox virus in domesticated chickens of Tikrit City, Iraq / Estudo patológico, molecular e filogenético do vírus da varíola aviária em frangos de corte domesticados da cidade de Tikrit, Iraque

Fowlpox virus (FPV) is one of the viruses affecting chickens worldwide, causing pathological and economic losses in the poultry industry. Viral lesions are easily recognizable by the eye and usually appear in the featherless areas, especially the head. Moreover, the virus could lead to blindness and mortality in some cases. This study diagnosed the suspected fowlpox cases, identified and classified the causative agent. We also analyzed the differences and similarities of closely related viruses at the neighboring and regional countries. Fifty samples were collected from three locations of Tikrit city from the domesticated chickens, which showed cutaneous lesions. Virus DNA was extracted directly from tissue samples before the nested PCR technique was performed. The virion core protein (P4b) gene is partially sequenced and analyzed with routine histological sectioning. Results showed that the virus causes pock lesions of dermal hyperplasia and hyperkeratosis. Hyperplasia and congestion of the chorioallantoic membrane were also recorded. The study also showed that the DNA of FPV could be extracted directly from animal tissue without further purification. The sequence analysis showed that the FPV was confirmed in all samples clustered in clade A identical with Iranian and Egyptian isolates. In conclusion, this study approved that the virus belongs to the classical dermal type of poxviruses and the short genetic distances between viruses related to closely neighboring countries. We also concluded that the conservative P4b gene included mutation sites that make this gene practical for diagnosing the virus and phylogenetic analysis.(AU)

O vírus da varíola aviária (VVA) é um dos vírus que acometem os frangos de corte em todo o mundo, causando perdas patológicas e econômicas na indústria aviária. As lesões causadas pelo vírus são facilmente reconhecidas pela observação visual e usualmente aparecem nas áreas do corpo das aves livres de penas, especialmente na cabeça. Além disso, em alguns casos a doença pode provocar a cegueira e a mortalidade de animais acometidos. O presente trabalho foi delineado para diagnosticar casos suspeitos de varíola aviária, identificar o agente causal e classificá-lo. Adicionalmente foram analisadas diferenças e similaridades com outros vírus estreitamente relacionados em localidades vizinhas e regionais. Cinquenta amostras foram colhidas em três localidades da cidade de Tikrit de frangos de corte, domesticados, que apresentavam lesões cutâneas. O DNA do vírus foi extraído diretamente das amostras de tecidos antes que a técnica de PCR fosse realizada. As proteínas do core do vírus, gene (P4b), foram parcialmente sequenciadas de analisadas em secções da rotina histológica. Os resultados obtidos revelaram que o vírus causa lesões variólicas com hiperplasia dermal e hiperqueratose. A hiperplasia e a congestão da membrana corioalantóica também foram registradas. O estudo também revelou que o DNA do VVA pode ser extraído diretamente de tecidos animais sem a realização de uma pré-purificação. A análise sequencial revelou que o VVA foi confirmado em todas as amostras agrupando-se em uma classe A, idêntica com isolados iranianos e egípcios. A conclusão obtida foi que o presente trabalho confirmou que o vírus pertence ao tipo dérmico clássico dos poxvirus e que as curtas distâncias genéticas entre os vírus relacionados são encontrados em países vizinhos. Também foi concluído que o gene conservador P4b inclui pontos de mutação que o tornam um gene prático para diagnosticar o vírus em análises filogenéticas.(AU)