Rapid Chagas diagnosis in clinical settings using a multiparametric assay

The development of an immunoassay for detecting circulating antibodies against Trypanosoma cruzi with a good performance appears to be crucial in clinical settings for the management of Chagas disease. Here we propose a new automated ELISA test performed on serum samples using 2 different T. cruzi antigens (a recombinant protein and a T. cruzi whole extract) placed in parallel in separate solid phases. This automated diagnostic tool allows the simultaneous analysis of a large number of sera, by determining the presence of antibodies against both antigens by a single run test, with high sensitivity and specificity. The simultaneous analysis of the reactivity against the 2 antigens in a biparametric modality reduces the percentage of false-negative sera and allows a more accurate diagnosis. Using this multiparametric approach, we propose an effective algorithm for the first step of Chagas diagnosis by performing a single test, with time and cost savings.     

内蒙古某院2011～2013年抗HIV1／2抗体筛查与确诊结果分析

目的：调查内蒙古医科大学附属医院门诊、体检及住院人群抗人类免疫缺陷病毒（HIV）感染状况,预估呼和浩特地区人群感染情况。方法利用化学发光免疫分析技术检测2011年8月至2013年8月内蒙古医科大学附属医院门诊、体检及住院人群 HIV 感染状况,有反应性标本利用免疫印迹试验（WB）法确诊。结果共检测108367例标本,初筛阳性率为0．0212％（23/108367）,确诊阳性率为0．0148％（16/108367）;WB 法确诊阳性符合率为69．6％（16/23）。 HIV 感染者以男性为主,年龄集中在20～60岁,并且以已婚者为主,感染者职业分布广泛,传播途径以性传播为主。结论内蒙古医科大学附属医院门诊、体检及住院人群 HIV 感染率低,趋势稳定。     

血液筛查中丙型肝炎病毒检测方法的应用评价

目的比较血液筛查中丙型肝炎病毒的检测方法,并探讨其应用价值。方法收集2011年8～12月血液筛查中酶联免疫吸附试验(ELISA)、丙型肝炎病毒抗体(抗-HCV)阳性标本共41例,使用重组免疫印迹试验进行确证;同时用新创、Ortho两种抗-HCV ELISA试剂以及Architect Anti-HCV Reagent化学发光试剂进行检测,比较三者结果的差异。结果统计学分析显示,3种检测方法的检测结果差异有统计学意义。重组免疫印迹试验检测HCV阳性35例,阴性6例,与Architect化学发光法结果相符,新创ELISA法检测41例全为阳性,Ortho ELISA法检测阳性33例,阴性8例。结论 Ortho试剂对HCV检测的特异性高于新创试剂,化学发光法对HCV检测的特异性高于ELISA法,化学发光法与ELISA法联合检测能提高血液筛查中HCV的阳性检出率,对可疑标本再做重组免疫印迹试验分析。     

Biological markers for evaluating therapeutic efficacy in Chagas disease,a systematic review

The most neglected aspects of Chagas disease (CD) have been patient care and treatment. Despite recent progress in the development of potentially improved drugs, there is no consensus among different research groups on the lack of therapeutic response markers to evaluate efficacy of newly proposed drugs early after treatment. A systematic review of current evidence regarding molecules which are potential biomarkers for therapeutic response has been conducted using quality assessment and target responses as primary criteria. The review provides a panorama of the cumulative evidence and specific needs for development of a battery of complementary biomarkers which together fulfill ideal or acceptable criteria to evaluate early responses to treatment for chronic CD. There are several marker candidates which together may fulfill acceptable criteria to indicate the efficacy of a trypanocidal treatment. Data from ongoing studies are considered essential to improve assessment of existing markers and to identify those for early follow-up of treated patients.     

Oscillometric blood pressure measurement: a simple method in screening for peripheral arterial disease

Blood pressure at the ankle level is a reliable indicator of peripheral arterial disease (PAD) and the ankle brachial index (ABI) is a useful non-invasive screening tool for the early detection of atherosclerosis. In the first part of the study, systolic blood pressures obtained by oscillometry and plethysmography were compared in 80 subjects referred for possible vascular disease. In the second part of the study, 31 general practitioners enrolled 1258 consecutive patients aged more than 60 years. ABI was estimated by oscillometry. Patients with an ABI lower than 0.9 were referred to the local hospital for standardized measurements. In the first part, oscillometry showed a sensitivity of 97% and a specificity of 62% with a positive and negative predictive value of 71% and 96%, respectively. In the second part, significant PAD was found in 111 cases corresponding to a prevalence of 12.2%. In this population, the oscillometry showed a positive predictive value of 47%. The presence of PAD was significantly correlated to exercise related leg pain, a diagnosis of hypertension and smoking, whereas no correlation could be found with a diagnosis of heart disease, stroke, or with the presence of diabetes. The prevalence of PAD was sufficiently high in subjects over the age of 60 years to warrant screening. The ankle brachial index based on measurements with an oscillometric device was shown reliable in the exclusion of PAD, thereby fulfilling an important criterion for the use in screening.     

Field evaluation of four novel enzyme immunoassays for Chagas' disease in Venezuela blood banks: comparison of assays using fixed-epimastigotes, fixed-trypomastigotes or trypomastigote excreted-secreted antigens from two Trypanosoma cruzi strains

Many serological tests have been developed for the diagnosis of Chagas' disease, but few have been subjected to a rigorous field evaluation. We have recently described several novel enzyme immunoassays (EIAs) based on fixed-whole organisms or trypomastigote excretory-secretory antigens (TESA) from different Trypanosoma cruzi strains (Tulahuen or Brazil). This study evaluated the most promising of these novel assays (e.g. fixed-epimastigotes, fixed-trypomastigotes, TESA Brazil and TESA Tulahuen antigens) in a field study of Venezuelan blood bank specimens. The assays were tested in an operator-blinded fashion using 2038 blood bank samples obtained from low and high T.cruzi prevalence regions of Venezuela (n= 1050 and n= 988 from Bolivar and Portuguesa states, respectively). Based on National Laboratory for Chagas Immunodiagnosis (NLCI) 'gold standard' results, all novel EIAs were superior to the commercial kit currently used in Venezuela, achieving 100% sensitivity and >99% specificity at optimal cut-off values. The novel assays identified seven false-negative samples compared with the routine screening performed by the Venezuelan blood bank although two samples were also misclassified as positive. Minor differences in the performance of the four novel assays were observed at lower arbitrary cut-off values. This study confirms the potential utility of both the fixed-organism and the TESA-based assays in the diagnosis of T.cruzi infection.     

新生儿疾病筛查血标本采集和运送中常见问题分析与对策

目的了解新生儿疾病筛查血标本采集和运送现状。方法选择2004年1~12月出生的新生儿310例为观察组,观察新生儿疾病筛查采集血标本的情况。发现实施新生儿筛查过程中,在采血部位、穿刺深度、血样干燥时间、产妇的配合等多个环节存在缺陷,并对2005年1~12月的新生儿疾病筛查检测对象310例(实施组)及时采取整改措施。结果实施组复查率明显下降。结论需重视对产科医护人员进行新生儿疾病筛查血标本采集、送检规范知识及操作培训,做好筛查宣教工作,改良采血部位及血样干燥时间,以提高标本采集合格率,确保标本送检质量。     

高效液相色谱分析在HbE筛查中的应用价值

目的探讨高效液相色谱分析法在HbE病筛查中的价值。方法应用高效液相色谱分析仪对24 779例样本进行血红蛋白(Hb)分析,HbA2≥11%的样本进行HbE基因检测。结果 24 779例标本中检出129例HbA2≥11%的样本,含量为14.0%～75.2%(27.2%±9.4%)。经基因检测均确诊为HbE病,包括HbE杂合子、HbE/α-珠蛋白生成障碍性贫血、HbE/β-珠蛋白生成障碍性贫血、HbE/α-β-珠蛋白生成障碍性贫血和HbE纯合子,其HbA2含量分别为(26.1±1.3)%、(18.2±1.8)%、(45.9±8.0)%、38.6%和(73.9±1.8)%。经ROC曲线分析HbA2筛查HbE的临界值为11.7%。结论高效液相色谱不仅能有效地筛查HbE病,还可以通过HbA2含量区分HbE病突变类型及其复合珠蛋白生成障碍性贫血的类型,是筛查HbE病的有效方法。     

Comparison of the analytic sensitivities of a recombinant immunoblot assay and the radioimmune precipitation assay for the detection of antibodies to Trypanosoma cruzi in patients with Chagas disease

The diagnosis of chronic Chagas disease usually is made by detecting antibodies to Trypanosoma cruzi, the protozoan parasite that causes this illness. A highly sensitive and specific immunoblot assay developed by us showed a higher analytic sensitivity than the radioimmune precipitation assay, which is used widely as a confirmatory test.     

The prevalence of celiac disease in Europe: Results of a centralized,international mass screening project

Abstract

Introduction. Although the prevalence of celiac disease (CD) has been extensively investigated in recent years, an accurate estimate of CD frequency in the European population is still lacking. The aims of this study were: 1) to establish accurately the prevalence of CD in a large sample of the European population (Finland, Germany, Italy, and UK), including both children and adults; and 2) to investigate whether the prevalence of CD significantly varies between different areas of the European continent.

Materials and methods. Samples were drawn from the four populations. All 29,212 participants were tested for CD by tissue transglutaminase (tTG) antibody test. Positive and border-line findings were further tested for serum endomysial antibodies (EMA). All serological determinations were centrally performed. Small-bowel biopsies were recommended to autoantibody-positive individuals. Previously diagnosed cases were identified.

Results. The overall CD prevalence (previously diagnosed plus anti-tTG and EMA positives) was 1.0% (95% CI 0.9–1.1). In subjects aged 30–64 years CD prevalence was 2.4% in Finland (2.0–2.8), 0.3% in Germany (0.1–0.4), and 0.7% in Italy (0.4–1.0). Sixty-eight percent of antibody-positive individuals showed small-bowel mucosal changes typical for CD (Marsh II/III lesion).

Conclusions. CD is common in Europe. CD prevalence shows large unexplained differences in adult age across different European countries.     

Accuracy of the water‐siphon test associated to barium study in a high prevalence gastro‐oesophageal reflux disease population: a novel statistical approach

Rationale, aims and objectives Gastro‐oesophageal reflux disease (GORD) is ‘a condition which develops when the reflux of gastric content causes troublesome symptoms or complications’. Instrumental diagnostic tests generally used for GORD are 24‐hour pH‐metry and upper gastrointestinal (GI) endoscopy but barium study associated with provocative manoeuvres such as the water‐siphon test (WST), has also been used for GORD. The aim of this paper was to estimate the accuracy of several tests in patients with GORD in a tertiary care setting, focusing on WST, which is rapid and non‐invasive, simple to perform and well‐tolerated by patients. Method A total of 172 consecutive patients, symptomatic for reflux referred to a tertiary medical centre, were considered and data regarding the WST, 24‐hour pH‐metry, upper GI endoscopy with histology were analysed using latent class analysis, a multivariable statistical method for estimating the accuracy of tests when a gold standard is not available. Results The overall proportion of GORD in the sample was estimated at 0.664 [95% confidence interval (CI) = (0.589; 0.731)]. WST proved to be the most sensitive [Se = 0.886; 95% CI = (0.688; 1.000)] compared with pH‐metry [Se = 0.620; 95% CI = (0.493; 0.745)] and endoscopy with histology [Se = 0.534; 95% CI = (0.273; 0.789)]. It was less specific [Sp = 0.537; 95% CI = (0.003; 1.000)] than pH‐metry [Sp = 0.547; 95% CI = (0.281; 0.813)], and even less than endoscopy with histology [Sp = 0.862; 95% CI = (0.495; 1.00)]. Positive predictive values were estimated at 0.792 [95% CI = (0.721; 0.862)] for WST, 0.731 [95% CI = (0.643; 0.819)] for pH‐metry and 0.886 [95% CI = (0.811; 0.961)] for endoscopy with histology. Negative predictive values were estimated at 0.707 [95% CI = (0.573; 0.841)] for WST, 0.422 [95% CI = (0.310; 0.534)] for pH‐metry and 0.484 [95% CI = (0.387; 0.581)] for endoscopy with histology. Conclusion Water‐siphon test might possibly be useful in patients with suspected GORD because it is highly sensitive and predictive. A positive outcome of the WST associated with a barium study can certainly justify upper GI endoscopy and support any pharmacological treatment of GORD.     

A beta-turn rich oats peptide as an antigen in an ELISA method for the screening of coeliac disease in a paediatric population

BACKGROUND: ELISA methods for the measurement of IgA antigliadin antibodies (AGA), both home-made and commercial systems, routinely employ wheat gliadin fractions as coating antigens. We investigate the sensitivity and specificity for CD diagnosis of a new ELISA method using a highly immunoreactive beta-turn rich gamma3-avenin peptide as an alternative coating antigen. METHODS: The assay was standardized with antihuman IgA peroxidase-conjugated as the second antibody. Alternatively, an ELISA based on the use of protein A-peroxidase was assayed to measure both IgG plus IgA antibodies. Sixty-three sera from healthy controls were analyzed to establish the system's cut-off point. Sera from 103 coeliac and from 65 noncoeliac children were tested; for diagnosis purposes, a small intestinal biopsy had been performed in all of them. RESULTS: For the IgA class antibodies assay a high sensitivity and specificity of 90.3% and 98.5%, respectively, was obtained, comparable to those achieved for IgA antiendomysium antibodies (EmA) with the same sera. CONCLUSIONS: In view of the high sensitivity and specificity obtained together with water solubility of the peptide and easiness for large-scale reproducible synthesis, the new AGA IgA avenin peptide ELISA represents a significant improvement in CD diagnosis in comparison with conventional established AGA IgA ELISA using crude gliadins as coating antigens.     

Measurement of methotrexate in human cerebrospinal fluid using a chemiluminescence immunoassay intended for serum and plasma matrices

BackgroundThe concentration of MTX in blood is often measured quickly and easily by immunoassays. Thus, immunoassays may facilitate the easy determination of the concentration of MTX in the cerebrospinal fluid (CSF). In this study, we measured methotrexate (MTX) concentrations in the CSF using a high‐performance liquid chromatography (HPLC) method intended for analyzing CSF matrices and a chemiluminescence immunoassay (CLIA) method intended for assessing serum and plasma matrices and verified the differences in the results of the two methods.MethodsHPLC analysis for MTX in the CSF was performed using a Prominence UFLC system with a C18 column. The HPLC method was validated in accordance with the 2018 FDA guideline. The CLIA method was performed using an ARCHITECT i1000SR system intended for serum and plasma matrices. A total of 47 CSF samples (14 clinical and 33 spiked specimens) were analyzed using the two methods.ResultsThe HPLC method passed the validation criteria. The concentration of MTX in the same sample, determined using the HPLC and CLIA methods, differed proportionally; the percent difference in the concentrations averaged −23.0% (95% confidence interval: −36.9% to −9.1%) as revealed by the Bland‐Altman plot. The relationship between the measured values, evaluated using the Passing‐Bablok regression, was as follows: HPLC = 1.205 × CLIA – 0.024.ConclusionThe equation deduced in this study can be used to correct the concentration of MTX measured using the CLIA method.     

Validity of analysis of FMRP expression in blood smears as a screening test for Fragile X Syndrome in the Indian population

Molecular diagnosis of Fragile X Syndrome (FXS) is carried out by PCR or Southern blot analysis on DNA isolated from leukocytes. These DNA analyses are time consuming and expensive, making it impractical for mass screening programs. We have recently standardized and tested the diagnostic potential of a rapid antibody test on blood smears, based on the presence of FMRP, the protein product of the FMR1 gene, in lymphocytes from normal individuals and the absence of FMRP in lymphocytes in patients with FXS. This test is essentially similar to the one developed at Erasmus University in the Netherlands, with suitable modifications. The diagnostic power of the antibody test is perfect for males, whereas the results are less specific for females. The cutoff value for affected male individuals, expressed as the percentage of FMRP-positive cells, was 20%. In normal individuals, the cutoff value was 85%. The results of the antibody test correlated well with that of Southern blots. Sensitivity of the test was 100% and specificity was 97.5%. This noninvasive test requires one or two drops of blood and is rapid, simple, and cheap, making it an ideal choice for large screening large groups of male mental retardates and neonates for FXS in developing countries such as India.     

实时声学造影和全功能声学密度定量技术评价冠心病患者心肌血流量的临床研究

目的　探讨实时声学造影以及全功能声学密度定量技术 (globalacousticdensity ,GAD)评价冠心病患者心肌血流量 (myocardialbloodflow ,MBF)的临床应用价值。 方法　对 18例冠心病患者行SonoVue经静脉声学造影检查 ,应用GAD定量其心肌血流量情况。结果　 18例患者均顺利完成SonoVue经静脉声学造影检查。GAD定量分析 :冠心病患者病变不明显冠状动脉供应节段的MBF明显高于狭窄冠状动脉供应的节段 [(61.94±3 1.0 1)dB2 /s对 (2 2 .0 9± 18.12 )dB2 /s ,P <0 .0 1] ;经皮冠状动脉成形术 支架植入术重建血管相关节段的MBF仍低于病变不明显冠状动脉供应的节段 [(2 8.84± 2 3 .94)dB2 /s对 (66.12± 3 3 .46)dB2 /s ,P <0 .0 1]。结论　实时声学造影及GAD能够定量分析冠心病患者心肌血流量情况。     

Ultrasonic measurement of fetal blood velocity wave form as a secondary diagnostic test in screening for intrauterine growth retardation

Based on routine fetometry screening at 32 weeks of gestation, 80 out of 3226 singleton pregnancies were suspected of intrauterine growth retardation (IUGR) and 72 of them were subjected to repeated fetal blood flow measurements by Doppler ultrasound for evaluation of the fetal condition. The maximum blood velocity wave form recorded from the fetal descending aorta and umbilical artery was classified as normal or abnormal depending on the presence or absence of positive end-diastolic blood flow. Compared to the pregnancies with normal fetal blood flow, the group of 30 pregnancies with abnormal blood flow patterns had significantly more pregnancy complications and more operative deliveries for fetal distress. In the latter group, all newborns but one were small-for-gestational age and had low 1-min Apgar scores more frequently. Fetal blood flow measurements have a good capacity for predicting unfavorable fetal outcomes and can be recommended for clinical use. The combination of ultrasound screening and Doppler blood flow measurement has reduced the number of pregnancies requiring intensive surveillance.     

The feasibility and outcome of a community-based primary prevention program for cardiovascular disease in the 21st century

ObjectiveThere is no evidence that systematic screening and risk factor modification in an unselected, asymptomatic population will reduce cardiovascular disease (CVD) mortality. This study aimed to evaluate the effectiveness of a primary care CVD prevention program on mortality during a 13-year follow-up.DesignA risk factor survey was sent, followed by a nurse-led lifestyle counselling to respondents with at least one CVD risk factor, and a general practitioner’s (GP) appointment for high-risk persons. Screening and interventions were performed during 2005–2006.SettingA public health care centre in the town of Harjavalta, Finland.SubjectsAll home-dwelling 45–70-year old inhabitants without manifested CVD or diabetes.Main outcome measuresAll-cause and CVD mortality.ResultsAltogether 74% (2121/2856) inhabitants responded to the invitation. The intervention was received by 1465 individuals (52% of the invited population): 398 risk persons had an appointment with a nurse, followed by an appointment with a GP for 1067 high-risk persons. During the follow-up, 370 persons died. Mortality among the non-respondents was twofold compared to the participants’. In subjects who received the intervention, the age- and gender-adjusted hazard ratio for all-cause mortality was 0.44 (95% CI: 0.36 to 0.54) compared to the subjects who did not receive the intervention.ConclusionsReducing mortality is possible in a primary care setting by raising health awareness in the community with screening, by targeted lifestyle counselling and evidence-based preventive medication for persons at high risk for CVD. Subjects not willing to participate in health surveys have the worst prognosis.

Key Points

• Previously, there is no evidence that systematic screening and risk factor modification in an unselected, asymptomatic population will reduce cardiovascular disease (CVD) mortality.
• With a stepwise screening program it is possible to scale the magnitude of CVD prevention in the community.
• Reducing mortality in a community is possible by screening, targeted lifestyle counselling, and by evidence-based preventive medication for high-risk persons.
• Subjects not willing to participate in health surveys have the worst prognosis.

     

The immunological diagnosis of HBsAg liver disease by combined screening for thee system in the serum and the HB core and surface antigens in liver biopsy samples

Summary Serological screening for HBeAg and anti-HBe, combined with the immunohistochemical localization of the hepatitis B core and surface antigen in 110 HBsAg carriers, established different immunological profiles indicative of the liver status and prognostic of the future absence or progression of the disease. Intrahepatic HBcAg and serum HBeAg appeared the most sensitive indexes of chronic and progressive liver disease, anti-HBe and large amounts of cytoplasmic HBsAg suggest, instead, the asymptomatic carrier state without liver damage. Only the nuclear localization of HBcAg in immunohistochemical studies was a reliable prognostic indicator of transition to chronicity; absence or presence of serum HBeAg was of no help in predicting the outcome of acute HBsAg hepatitis.