Direct fluorescent antibody assay and polymerase chain reaction for the detection of Chlamydia trachomatis in patients with vernal keratoconjunctivitis

OBJECTIVES:

To identify Chlamydia trachomatis via polymerase chain reaction and a direct fluorescent antibody assay in patients with vernal keratoconjunctivitis while comparing the efficacies of both tests for detecting Chlamydia trachomatis in these conditions.

METHODS:

Conjunctival scraping samples were obtained from 177 patients who were divided into two groups: a vernal keratoconjunctivitis group (group A) and a control group (group B). The polymerase chain reaction and a direct fluorescent antibody assay were performed. Sensitivity, specificity, receiver operating characteristic curves, and areas under the curve were calculated for both tests in groups A and B. Receiver operating characteristic curves were plotted using a categorical variable with only two possible outcomes (positive and negative).

RESULTS:

Statistical analysis revealed a significant association between vernal keratoconjunctivitis and Chlamydia trachomatis infection detected by a direct fluorescent antibody assay with high sensitivity and specificity. All patients in group A with positive polymerase chain reactions also presented with positive direct fluorescent antibody assays.

CONCLUSION:

The association between vernal keratoconjunctivitis and Chlamydia trachomatis infection was confirmed by positive direct fluorescent antibody assays in 49.4% of vernal keratoconjunctivitis patients and by positive polymerase chain reactions in 20% of these patients. The direct fluorescent antibody assay detected Chlamydia trachomatis in a higher number of patients than did the polymerase chain reaction. Although the diagnosis of trachoma is essentially clinical, the disease may not be detected in vernal keratoconjunctivitis patients. Due to the high frequency of chlamydial infection detected in patients with vernal keratoconjunctivitis, we suggest considering routine laboratory tests to detect Chlamydia trachomatis in patients with severe and refractory allergic disease.     

Poor correlation between microimmunofluorescence serology and polymerase chain reaction for detection of vascular Chlamydia pneumoniae infection in coronary artery disease patients

Chlamydia pneumoniae has been associated to coronary artery disease by various methods including recovery of viable bacteria from plaques. The pathogenetical relevance of this is unclear but investigation of antichlamydial therapy in coronary arteriosclerosis is already in progress. The microimmunofluorescence test (MIF), the only species-specific serological assay available, might be considered useful in identifying patients with vascular chlamydial infection. However, this has never been systematically examined. We compared levels of C. pneumoniae antibodies in sera using MIF with direct detection of C. pneumoniae in coronary artery segments from 158 patients undergoing myocardial revascularization. A polymerase chain reaction (PCR) protocol, recently evaluated for use with vascular materials, detected C. pneumoniae infection in 34 patients. Correlation of serology and PCR was poor: in relation to PCR, MIF-IgG analysis had 21% sensitivity, 90% specificity, 37% positive predictive value, and 81% negative predictive value for detection of chlamydial presence. Thus, the MIF test currently appears not suitable to predict individual vascular C. pneumoniae infection. Received: 19 June 1998     

一种同时检测丙型与庚型肝炎病毒的逆转录-巢式聚合酶链反应方法

目的庚型肝炎病毒（ＨＧＶ）与丙型肝炎病毒（ＨＣＶ）同属黄病毒科，且传播途径相似，重叠感染率高，本研究旨在建立一种同时检测ＨＧＶ与ＨＣＶ感染的方法。方法根据ＨＣＶ与ＨＧＶ的基因序列分别选取５’－ＵＴＲ（ＨＣＶ）与ＮＳ３（ＨＧＶ）的两套引物，在同一管内进行逆转录－巢式聚合酶链反应，并初步应用于１５３例标本。结果该方法能同时检出ＨＧＶ与ＨＣＶ感染，扩增片段大小与设计相符。结论该方法简便特异，适用于临床检测     

慢性肝炎和肝癌病人血清中乙型肝炎病毒DNA的检测

为了了解慢性肝炎和肝癌病人患者体内乙型肝炎病毒（ＨＢＶ）复制与ＨＢＶ血清标志之间的关系，用酶联免疫吸附实验（ＥＬＩＳＡ）、聚合酶链反应（ＰＣＲ）及斑点杂交方法对６１例慢性肝炎和４７例肝癌患者的ＨＢＶ表面抗原（ＨＢｓＡｇ）、相关ｅ抗原（ＨＢｅＡｇ）、表面抗体（抗－ＨＢｓ）、核心抗体（抗－ＨＢｃ）、相关ｅ抗体（抗－ＨＢｅ）进行了检测。结果表明：ＨＢＶＤＮＡ在ＨＢｓＡｇ、ＨＢｅＡｇ、／抗－ＨＢｃ阳性的慢性肝炎和肝癌患者血清中的检出率分别为９０．５０％和５０．００％；在ＨＢｓＡｇ／抗－ＨＢｅ、抗－ＨＢｃ阳性者的检出率分别为４５．４０％和７．１４％；在ＨＢｓＡｇ阳性、ＨＢｅＡｇ阴性／抗－ＨＢｅ阴性者中的检出率分别为６０．００％和４０．００％；ＨＢｓＡｇ阴性、／抗－ＨＢｃ阳性或／抗－ＨＢｅ阳性或／抗－ＨＢｓ阳性者中的检出率分别为２０．００％和２２．２２％；在血清学指标全阴性时，慢性肝炎和肝癌患者血清中ＨＢＶＤＮＡ的检出率均为０。实验提示：无论是肝炎或肝癌，在ＨＢｓＡｇ、ＨＢｅＡｇ同时阳性时，ＨＢＶ复制最为活跃；在单独ＨＢｓＡｇ阳性时，ＨＢＶ有一定程度的复制；ＨＢＶ复制在肝癌细胞中受到一定程度的抑制。     

Analysis of c-myc DNA amplification in non-small cell lung carcinoma in comparison with small cell lung carcinoma using polymerase chain reaction

Previous studies of c-myc DNA amplification in lung cancer have focused primarily on analysis of small cell carcinoma or its tumor cell lines. There are few data about c-myc DNA amplification in histological types of lung cancer other than small cell carcinoma. Therefore the present study was conducted to investigate c-myc oncogene amplification in non-small cell lung carcinoma. We studied 46 lung tumor specimens for c-myc DNA amplification (15 adenocarcinomas, 15 squamous cell carcinomas, 6 large cell carcinomas, and 10 small cell carcinomas). Polymerase chain reaction, digoxigenin DNA labeling, and elecrophoresis were utilized to investigate the c-myc copy number in the lung tumor specimens. The c-myc copy number of non-small cell carcinoma ranged from 1.5 to more than 20.0 in adenocarcinoma and squamous cell carcinoma, and from 6.0 to 12.0 in large cell carcinoma. That of small cell carcinoma ranged from 1.8 to 12.0. The c-myc copy number of non-small cell carcinoma was significantly higher that than of small cell carcinoma (Wilcoxon rank sum test, Z=2.06, P=0.040). However, the differences in c-myc copy number among these four histological types were not statistically significant. Amplification of c-myc (more than 4 copies) was observed not only in small cell carcinoma but also in non-small cell carcinoma at similarly high frequency (12/15 in adenocarcinoma and squamous cell carcinoma, 6/6 in large cell carcinoma, and 9/10 in small cell carcinoma). Received: 17 October 2000 / Accepted: 7 May 2001     

Histopathologic, immunohistochemical, and polymerase chain reaction assays in the study of cases with fatal sporadic myocarditis

Paraffin tissue blocks from 27 cases with sporadic myocarditis were collected during a 12-year period at a single medical examiner's office. Blocks were studied by using histopathology; immunohistochemistry for viruses (adenovirus, enterovirus, influenza A and B, and human herpes types 4 and 5), bacteria (Neisseria meningitidis, Ehrlichia sp, spotted fever group Rickettsia) and parasites (Toxoplasma gondii and Trypanosoma cruzi); and polymerase chain reaction (PCR)/RT-PCR for adenovirus and enterovirus. We identified enterovirus in 5 (18.5%) cases and Sarcocystis in a 36-year-old woman who had focal inflammation and myocyte necrosis. Immunohistochemical evidence of enteroviruses was found in the myocytes of 2 patients less than 6 months old who had diffuse mononuclear myocardial inflammation, interstitial pneumonitis; one also had encephalitis. In these 2 patients, the presence of enterovirus was confirmed by RT-PCR targeting the 5' nontranslated region and was serotyped as coxsackievirus B2 by sequencing the VP1 capsid region. In another 3 cases (ages 12, 47, and 54), enterovirus was detected by the 5' nontranslated region region; VP1 sequencing identified these as echoviruses 6, 13, and 7, respectively. Accurately identifying an infectious agent is the foundation for clinical and public health interventions. Despite using multiple diagnostic methods, an organism could only be detected in a small proportion of sporadic myocarditis cases.     

A new approach of real time polymerase chain reaction in detection of vancomycin-resistant enterococci and its comparison with other methods

Background: Vancomycin-resistant enterococci (VRE) are third leading cause of nosocomial infection. Therefore, an effective, accurate and early detection of VRE along with their minimum inhibitory concentrations (MICs) is required to initiate appropriate therapy and thus better patient outcome. Objective: To detect VRE by real time quantitative polymerase chain reaction (Q-PCR) and to compare the results with chrom ID (C-ID) VRE and PCR. Further the study also determined the fold change of vanA gene by Q-PCR in different groups of VRE isolates classified on the basis of glycopeptides MIC range. Subjects and Methods: A total of 145 (80 VRE and 65 vancomycin-susceptible enterococci) clinical isolates were included in the study. After the screening of VRE isolates MICs were determined by E-test and agar dilution method. Further VRE was confirmed by vanA and vanB specific PCR and Q-PCR. Results: The sensitivity and specificity of C-ID VRE was 100% and 95.38%. However, sensitivity and specificity of conventional and Q-PCR were found to be 100%. Conventional and Q-PCR confirmed that our all isolates were vanA type. Mean R value was significantly higher (P < 0.001) in group I (MIC> 1024 μg/ml) when compared to group II (MIC 512-1024 μg/ml) and group III (MIC < 512 μg/ml) isolates. The mean R was also significantly higher in group II when compared to group III isolates (P = 0.038). Conclusion: Q-PCR is a rapid technique to detect vanA in enterococci along with their MIC range, thus it might be helpful to decide the treatment modalities of infections caused by VRE.     

Loop mediated isothermal amplification assay using hydroxy naphthol blue,conventional polymerase chain reaction and real-time PCR in the diagnosis of intraocular tuberculosis

This study is a comparative evaluation (Chi-square test) of a closed tube loop mediated isothermal amplification assay using hydroxy naphthol blue dye (HNB-LAMP), real-time polymerase chain reaction (PCR) and conventional PCR in the diagnosis of intraocular tuberculosis. Considering clinical presentation as the gold standard in 33 patients, the sensitivity of HNB-LAMP assay (75.8%) was higher (not significant, P value 0.2) than conventional PCR (57.6%) and lower than real-time PCR (90.9%). Specificity was 100% by all three methods. No amplification was observed in negative controls (n = 20) by all three methods. The cost of the HNB-LAMP assay was Rs. 500.00 and it does not require thermocycler, therefore, it can be used as an alternative to conventional PCR in resource-poor settings.     

Double-nested polymerase chain reaction for detection of caprine arthritis-encephalitis virus proviral DNA in blood, milk, and tissues of infected goats

A nested polymerase chain reaction (PCR) for detecting proviral DNA of caprine arthritis-encephalitis virus (CAEV) in biological samples was developed. Primers for both gag and pol sequences of the CAEV genome were included in a single tube for simultaneous amplification (‘double’ PCR), and the resulting bands were resolved visually in ethidium bromide-stained agarose gels. Internal gag and pol probes were used to verify the identity of the amplified products by non-radioactive Southern hybridization. Final confirmation of the identity of representative PCR bands was provided by DNA sequence analysis. A comparison between the PCR and an antibody ELISA (with recombinant CAEV p28 as target) using 141 caprine blood samples indicated very strong agreement between the two assays (κ = 0.912). Four of 7 goats with indeterminate ELISA results were PCR-positive as were 5 of 40 (12.5%) seronegative goats, most probably indicating delayed seroconversion. Eleven of 27 goats (41%) PCR-positive on blood had detectable CAEV proviral DNA in milk. Proviral DNA was also detected in lung, mesenteric lymph node, bone marrow, synovial membrane, and mammary gland of a seropositive, clinically affected goat, but not in equivalent tissues of a healthy seronegative goat.     

FMS hemizygosity in myeloid dysplasia and acute myeloid leukemia with chromosomal aberration del(5)(q) demonstrated by polymerase chain reaction

Interstitial deletions of the long arm of chromosome 5 del(5)(q), are recurring aberrations in the myelodysplastic syndrome and acute myeloid leukemia. Several genes located in region (5)(q23–34) have been implicated as being of pathogenic importance. In this study seven samples of six patients with myelodysplastic syndrome and acute myeloid leukemia who have the del(5)(q) aberration were analyzed by polymerase chain reaction (PCR) and Southern blot technique. FMS hemizygosity was demonstrated in all patients. PCR analysis from peripheral blood samples confirmed the observations of this aberration found by semiquantitative Southern blot. PCR-based analysis can be used for primary diagnosis in addition to cytogenetic evaluation and for follow-up in patients with del(5)(q) aberration.Abbreviations PCR Polymerase chain reaction - MDS Myelodysplastic syndrome - AML Acute myeloid leukemia - RA Refractory anemia - RAEB Refractory anemia with excess of blasts - RAEBt Refractory anemia with excess of blasts in transformation to acute leukemia     

Rapid,sensitive, specific,and quantitative detection of human T-cell leukemia virus type 1 sequence in peripheral blood mononuclear cells by an improved polymerase chain reaction method with nested primers

Improving on the nested double polymerase chain reaction (PCR) described previously, we have developed a new two-step PCR (TS-PCR) method for detecting more specifically the human T-cell leukemia virus type 1 (HTLV-1) proviral sequences in peripheral blood mononuclear cells (PBMC). In our TS-PCR method, the point of modification is to use optimal concentrations of primers in the first amplification step in the range of 0.01–0.025 µM. This increases sensitivity and specificity enough to detect from 1 to 10⁵ copies of template DNA without radioisotopes. This method is rapid because of completion in 1 day and is also applicable for quantitative detection of clinical specimens. The data show that the quantitative detection of HTLV-1 proviral sequences by this method correlates with the anti-HTLV-1 antibody titers from serologic analysis of seropositive healthy carriers. Moreover, the TS-PCR method using each specific primer was also attempted for successful detection of other viral genomes; therefore, the principle of this method is widely suitable for routine detection of genomes in the basic and clinical microbiological fields.