聚合酶链反应技术诊断苯丙酮尿症

为早期确诊，应用聚合酶链反应（ＰＣＲ）结合限制性内切酶（ＥＣＯＲＩ、ＥＣＯＲＶ）方法，对初筛出具有高度苯丙酮尿症（ＰＫＵ）可能的６例患儿，行苯丙氨酸羟化酶基因分析。结果确诊３例，还为其中１例患儿母亲再次妊娠的胎儿作产前ＰＣＲ检测，鉴定出与ＰＫＵ致病基因相连锁的遗传特异片段，据此诊断出胎儿为杂合子，并经随访证实。应用ＰＣＲ技术对ＰＫＵ患儿早期诊断乃至产前诊断是可靠且可行的。     

Blood and urine samples as useful sources for the direct detection of tuberculosis by polymerase chain reaction

The aim of the study was to assess the utility of the polymerase chain reaction (PCR) assay in blood and urine for the diagnosis of tuberculosis (TB). We prospectively evaluated the usefulness of PCR performed in blood and urine samples from patients with proved or probable TB compared with a control group of patients. The PCR technique was performed using IS6110 primers. We included in the study 57 patients (43 with definite TB and 14 with probable TB) and 26 controls. Blood and urine samples were drawn at the time of microbiologic diagnosis and 3, 6, 9, and 12 months later. Cultures were positive in the early period (<1 month after treatment) in 11 of 57 patients (19%) with probable or definite TB, in comparison with 42% of patients (24/57) who yielded a positive PCR (P = 0.02). Urine samples increased the sensitivity of PCR determination in blood samples by 10%. The PCR in blood and/or urine was positive in 41% of patients with pulmonary TB, in 36% of patients with extrapulmonary TB, and in 50% of patients with disseminated TB. Mycobacterium tuberculosis was still detectable by PCR in 5 of 13 patients with cured TB after 1 or more months of antituberculous treatment. The PCR detection of M. tuberculosis in blood and urine samples is useful for the diagnosis of different clinical forms of TB, mostly in those patients in which sample extraction is difficult or requires aggressive techniques. The sensitivity of this technique could be improved studying more than 1 sample in each patient, even after initiating an antituberculous treatment.     

Use of polymerase chain reaction for diagnosis of inherited disorders

The polymerase chain reaction (PCR) is a rapid method for generating a 10(6)- to 10(7)-fold increase in the number of copies of a discrete DNA or RNA sequence. The technique is being used for rapid prenatal diagnosis and carrier testing of several inherited disorders. After PCR, mutations producing single-gene disorders can be detected by several different methods, including endonuclease digestion and gel electrophoresis (applicable when a mutation affects an endonuclease recognition site), gel electrophoresis (used for detection of deletions), and hybridization to an oligonucleotide probe specific for a mutation. Less often, gene sequencing of a PCR product is used to rapidly identify a mutation. In addition, the PCR technique can be applied to polymorphism analysis to provide diagnosis by linkage analysis. In other areas, PCR is being used to detect and characterize microbial pathogens and to characterize mutations associated with carcinogenesis. The PCR method is useful in situations in which the amount of DNA sample is limited, such as in forensics and prenatal testing, or in which the quality of the DNA sample is poor.     

Laboratory diagnosis of toxoplasmosis using polymerase chain reaction

Polymorphism of clinical manifestations in Toxoplasma infection and variegated disease patterns virtually rule out the diagnosis based solely on clinical symptoms, which makes modern laboratory tests particularly important. Amplification test system based on the polymerase chain reaction has been developed for the diagnosis of Toxoplasma infection. Computer analysis of nucleotide sequence of Toxoplasma gondii surface antigen gene P30 was analyzed, which helped choose and synthesize specific oligonucleotide primers. A method for biological material processing was selected, allowing sufficient DNA output. Optimal conditions for amplification reaction, ensuring absolute specificity and high (10-100 cells/sample) sensitivity, were determined.     

微量聚合酶链反应对人类白细胞抗原的基因分型

目的 探讨应用于移植的人类白细胞抗原（ＨＬＡ）二类基因（ＤＲＢ／ＤＱＢ）快速分型新技术。方法 采用快速ＤＮＡ抽提技术,建立了ＨＬＡ＿ＤＲＢ／ＤＱＢ微量序列特异性引物聚合酶链反应基因分型方法,对１４２份供受者ＤＮＡ进行ＨＬＡ－ＤＲＢ／ＤＱＢ基因分型,并与单克隆抗体一叔法ＨＬＡ血清学分型技术进行对比研究。结果 应用微量ＰＣＲ－ＳＳＰ方法共检出１３种ＤＲＢ１等位基因和 ＤＱＢ１等位基因,与血清学分型结果     

Comparison of polymerase chain reaction with other laboratory methods for the diagnosis of American cutaneous leishmaniasis: diagnosis of cutaneous leishmaniasis by polymerase chain reaction

An evaluation of 5 laboratory methods for diagnosing American cutaneous leishmaniasis (ACL) was carried out on patients from an endemic area of Brazil. From 164 patients presenting cutaneous lesions, and suspected to have ACL, 133 (81.1%) were confirmed for the disease by Montenegro skin test (MST) and/or parasitologic examination (PE). In both groups of patients, the positivity of polymerase chain reaction (PCR) was similar to that of immunofluorescence assay and enzyme-linked immunosorbent assay, and higher than that of MST and PE (P < .05). In the group of patients suspected to have ACL, PCR presented the same positivity as PE and MST together. No correlation between positivity of the laboratory methods and clinical or epidemiologic aspects was observed. Our data confirmed the value of PCR as an alternative laboratory method for diagnosing ACL, especially for those patients with negative PE and MST.     

PCR检测技术在结核病诊断中的价值

用ＰＣＲ技术对１７５例临床可疑结核病，但常规培养或抗酸染色阴性的病理标本中结核菌ＤＮＡ进行了检测。结果发现有２２．３％（３９／１７５）的样本结核菌ＤＮＡ阳性。结果提示，ＰＣＲ技术在检测结核菌ＤＮＡ中具有简便、快速和灵敏的特点，其阳性结果说明被测样品中有结核菌的存在，对结核病的确诊有重要辅助意义。     

Evaluation of polymerase chain reaction as an additional tool for the diagnosis of low-intensity Schistosoma mansoni infection

The aim of the present study was to evaluate polymerase chain reaction (PCR) as an alternative tool for diagnosing schistosomiasis in individuals with low-level parasite burden from areas of low endemicity or under occasional risk of infection by Schistosoma mansoni. A total of 102 samples were tested in this study using 2 PCR assays utilizing distinct primer pairs. One of the primer pairs was targeted to a highly repeated 121-base pair sequence of S. mansoni, and the other was targeted to Schistosoma 28S rDNA. The samples were divided into 4 groups according to parasite burden of the individual as follows: 16 individuals with schistosomiasis excreting less than 10 eggs per gram of feces (EPG), 18 individuals excreting higher than 10 EPG, 22 individuals with reactive IgG-ELISA against S. mansoni soluble membrane antigen and negative coproscopy, and 46 controls samples including 25 individuals with other intestinal parasites and 21 individuals with negative parasitologic examination. The results obtained with stool samples from individuals with schistosomiasis showed a high sensitivity for PCR as S. mansoni DNA was detected in 91% (31/34) of the samples analyzed. No amplification was observed in 3 stool samples from individuals excreting below 10 EPG. The specificity of the test for both pairs of primers was 100%. In the group of seropositive individuals, S. mansoni DNA was detected in 59% (13/22) of fecal samples, corroborating the serologic results. Overall, PCR can be an important tool for detecting S. mansoni infection in individuals excreting few eggs in feces. Moreover, the determination of the infection through the detection of S. mansoni DNA in stool samples from seropositive individuals represents a new means of confirming the results of IgG-ELISA for schistosomiasis. Therefore, studies in this direction should be encouraged and extended.     

PCR技术在诊断一期梅毒中的应用

目的应用PCR技术检测患者分泌物中梅毒螺旋体(TP)，探讨其在一期梅毒诊断中的作用。方法用PCR法检测47例梅毒疑似患者的分泌物和血清，同时检测82例乙型肝炎患者、28例类风湿性关节炎患者和30例健康对照者的血清中TP。用ELISA法、TPPA法和TRUST法分别检测以上各例血清中梅毒特异性抗体和非特异性抗体。结果PCR法检测梅毒疑似患者分泌物和血清、乙型肝炎患者和类风湿性关节炎患者及健康人血清，TP-DNA阳性率分别是91．5％(43／47)、30％(14／47)、0％、0%；ELISA法、TPPA法和TRUST法检测以上各例血清中特异性抗体和非特异性抗体阳性率分别是72％(34／47)、72％(34／47)、68％(32／47)(梅毒疑似病例)；1．2％(1／82)、1．2％(1／82)、3．7％(3／82)(乙型肝炎患者)；3．6％(1／28)、3．6％(1／28)、17．9％(5／28)(类风湿性关节炎患者)；0％、0％、0％(健康对照者)。结论应用PCR技术检测患者分泌物中TP-DNA，是诊断一期梅毒灵敏、准确而较理想的方法。     

Ileal perforation and reactive hemophagocytic syndrome in a patient with disseminated histoplasmosis: the role of the real-time polymerase chain reaction in the diagnosis and successful treatment with amphotericin B lipid complex

The following case illustrates an ileal perforation and reactive hemophagocytic syndrome (RHS) resulting from disseminated histoplasmosis in a patient with Human Immunodeficiency Virus (HIV) from Puerto Rico. Although the diagnosis was established by histopathologic findings and a positive bone marrow culture, Histoplasma capsulatum-specific real-time Polymerase Chain Reaction (PCR) allowed to confirm the diagnosis from formalin-fixed, paraffin-embedded tissue. Interestingly, the Histoplasma antigens in both serum and urine samples were falsely negative. Amphotericin B lipid complex (Abelcet), followed by oral itraconazole, led to a successful response and resolution of symptoms. A short review of the clinical signs and symptoms, diagnostic tests, and therapeutic options for disseminated histoplasmosis is done, with emphasis on the role of Histoplasma-specific real-time PCR as a molecular diagnostic tool and the efficacy of treatment with one of the lipid formulations of amphotericin B.     

Sensitivity of culture and polymerase chain reaction for the etiologic diagnosis of erythema migrans

Skin biopsy samples from 150 patients with typical cutaneous manifestation of Lyme borreliosis, erythema migrans, were cultivated for the presence of Borrelia burgdorferi sensu lato in modified Kelly Pettenkofer (MKP) medium and analysed with two different polymerase chain reactions using either flagellin or nested OspA primers. Cultivation was successful in 75 of 150 (50%) skin samples. Out of 70 strains that were typed using PFGE, B. afzelii was identified in 60 (86%), B. garinii in 10 (14%) specimens, while no B. burgdorferi sensu stricto strains were found. B. burgdorferi sensu lato DNA was detected with polymerase chain reaction in 28% and 61% of skin samples, using flagellin and nested OspA primers, respectively. Concordant results in all three procedures employed in the present study were found in 62 (41%) specimens: 25/150 (17%) were positive with all three methods and 37/150 (25%) samples were completely negative.     

Evaluation of a real-time polymerase chain reaction assay for the laboratory diagnosis of giardiasis

A real-time polymerase chain reaction (PCR) assay was evaluated in comparison with the combination of conventional methods (microscopic examination and antigen detection assay) during the period 2006 to 2008 on 771 fecal samples belonging to 386 patients to assess its usefulness for an accurate laboratory diagnosis of giardiasis. The real-time PCR assay detected Giardia intestinalis DNA in 195 samples (106 patients), including 26 samples (21 patients) negative by the conventional assays. Among the 21 patients, in 8 cases, giardiasis was previously diagnosed also by conventional methods in additional samples of the same patients, whereas in 13, it would have been undiagnosed if real-time PCR assay was not used. The real-time PCR assay demonstrated a detection limit of 2 cysts per reaction and 100% specificity and sensitivity compared to conventional methods. A genotype analysis targeting the β-giardin gene allowed to identify 53 samples (23 patients) containing genotype A and 59 samples (45 patients) containing genotype B.     

聚合酶链反应临床应用的优越性和局限性

聚合酶链反应(PCR)技术自1983年问世以来，因其对基因或特定核酸序列在短时间内具有极大的扩增效率，已广泛应用于感染性疾病、肿瘤、遗传病、寄生虫病、法医学、动植物和考古等诊断和研究领域，并在某些方面呈现出几乎难以替代的优势。PCR用于疾病的临床诊断后，使人们对蛋白分子表型的认识，进一步深入到了遗传物质——核酸分子的探索，也使临床检验诊断学科中的临床分子诊断技术得到了飞速发展。像任何自然界的事物一样，PCR虽然有其无可比拟的优点，但也有其一定的局限性。如果在临床实际应用中，不遵循客观规则，也很容易产生非PCR技术问题所致的错误检验结果。     

Survey of urine from transplant recipients for polyomaviruses JC and BK using the polymerase chain reaction.

Using polymerase chain reaction (PCR), we examined 108 urine specimens from 39 post transplant patients for polyomaviruses JC (JCV) and BK (BKV). Urine sediments were collected and subjected to 30 cycles of amplification. PCR products were resolved by agarose gel electrophoresis, transferred to nylon membranes by Southern blot, and hybridized with radiolabelled probes. Polyomavirus DNA was found in urine specimens from 17 out of 39 patients (44%). Both viruses were detected in specimens from nine patients, JCV alone in five, and BKV alone in three. In comparison, polyomavirus was detected in only five of 22 PCR positive specimens by shell vial cell culture assay. Our results show a high prevalence of polyomavirus shedding after transplantation and suggest a higher rate of JC viruria than previously reported.     

A urine-based polymerase chain reaction method for the diagnosis of visceral leishmaniasis in immunocompetent patients

In the Mediterranean basin and Middle East, including Iran, visceral leishmaniasis (VL), also known as kala-azar, is caused by Leishmania donovani infantum. For the first time, the use of urine samples for the diagnosis of VL in immunocompetent patients has been used in this study. Based on its high sensitivity and specificity, as well as simplicity, this approach can serve as a valuable tool in the diagnosis of VL. We studied 60 urine samples from 60 individuals, 30 of which were patients with VL confirmed by parasitology, serology, or molecular methods, 5 were from healthy individuals, and 25 were from patients with cutaneous leishmaniasis, malaria, brucellosis, and hydatid cyst. Out of 30 samples from confirmed VL immunocompetent patients, 29 were positive (sensitivity, 96.8%) by polymerase chain reaction (RV1 and RV2 primers), and all the remaining 30 samples either from healthy individuals or patients with other diseases were negative (specificity, 100%). High sensitivity, specificity, and simplicity of the test can serve as a valuable tool in the diagnosis of VL.     

尿液中大肠埃希菌实时荧光定量聚合酶链反应检测方法的建立

目的建立实时荧光定量聚合酶链反应（RQ—PCR）检测大肠埃希菌的方法,检测泌尿道感染患者尿液样本,评估应用RQ-PCR法在检测大肠埃希菌尿路感染的意义。方法选择大肠埃希菌β-右旋半乳糖苷酶基因作为检测靶基因设计引物,建立SYBRGREENIRQ—PCR检测体系。结果引物特异性好,标准曲线相关系数在0．990～0．996之间。熔解曲线显示产物特异性较强,无非目的条带和二聚体产生。在最低检测限（10^2拷贝／止）以上,能对大肠埃希菌样本进行检测,且重复性好。结论RQ—PCR是一种快速、敏感、特异、重复性好的定量检测大肠埃希菌质粒DNA方法,可用于定量检测临床患者尿液样本中大肠埃希菌含量。     

Real-time polymerase chain reaction for diagnosis and quantitation of negative strand of chikungunya virus

Quantitative real-time polymerase chain reaction (qRT-PCR) is useful for diagnosis and studying virus replication. We developed positive- and negative-strand qRT-PCR assays to detect nsP3 of chikungunya virus (CHIKV), a positive-strand RNA alphavirus that causes epidemic fever, rash, and arthritis. The positive- and negative-strand qRT-PCR assays had limits of quantification of 1 and 3 log₁₀ RNA copies/reaction, respectively. Compared to a published E1 diagnostic assay using 30 laboratory-confirmed clinical samples, the positive-strand nsP3 qRT-PCR assay had higher R² and efficiency and detected more positive samples. Peak viral load of 12.9 log₁₀ RNA copies/mL was reached on day 2 of illness, and RNA was detectable up to day 9, even in the presence of anti-CHIKV IgM. There was no correlation between viral load and persistent arthralgia. The positive-strand nsP3 assay is suitable for diagnosis, while the negative-strand nsP3 assay, which uses tagged primers to increase specificity, is useful for study of active viral replication kinetics.