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A single, multiplex analysis for all relevant activating NRAS gene mutations using heteroduplex generators.

We describe a multiplex polymerase chain reaction (PCR)-based test that detected all relevant NRAS activating mutations using a single PCR followed directly by electrophoresis. The test uses a Universal Heteroduplex Generator (UHG) to detect exon-2 (codon 61) NRAS mutations in multiplex with an UHG for exon-1 (codons 12 and 13). The method differentiated all 19 relevant mutations in these exons and showed a mutation independent sensitivity of approximately 6%. The sensitive, specific detection of all NRAS activating mutations using this single rapid test represents a minimum workload and could be applied readily for large-scale screening and for routine analysis.

Base Sequence↗

Prospective application of a multiplex reverse transcription-polymerase chain reaction assay for the detection of balanced translocations in leukaemia: a single-laboratory study of 390 paediatric and adult patients.

The upfront application of molecular methods for identifying the fusion transcripts arising from balanced translocations in haematopoietic malignancies has several advantages: sensitivity is independent of its frequency, i.e. rare ones are not missed, cytogenetically cryptic aberrations are identified and it provides a platform for minimal residual disease (MRD) detection. Employing a multiplex reverse transcription polymerase chain reaction (RT-PCR) assay identifying 27 fusion transcripts we prospectively analysed blood and/or bone marrow samples from 390 patients referred for diagnosis and treatment for acute leukaemia and chronic myeloproliferative disorders (CMPD) from a geographically well-defined region in Denmark. A total of 233 patients were diagnosed with acute myeloid leukaemia (AML), 95 with acute lymphoblastic leukaemia (ALL) origin and 62 patients were recorded as CMPD. Twenty-three percent AML, 32% ALL and 55% CMPD patients exhibited chromosomal aberrations detected by the multiplex RT-PCR. Cytogenetically cryptic translocations were seen in 15% of the cases. Conversely, the cytogenetic analysis identified chromosomal aberrations other than translocations in 45% of AML cases and 63% of ALL cases. We conclude that, while the fraction of translocation positive leukaemia patients in an unselected cohort is lower than hitherto believed, a molecular approach to their diagnosis is worthwhile, partly for identifying cryptic and rare translocations, partly for monitoring MRD.

Acute Disease↗

Multiplex riboprobes for the detection of virulent Yersinia enterocolitica and simple methods for their preparation.

A simple multiplex riboprobe system for detection of virulent Yersinia enterocolitica was developed using a pool of RNA probes specific for various chromosomal and plasmid-borne virulence gene sequences (yadA, virC, ail and yst). Riboprobes were synthesized by a rapid, simple and efficient technique involving in vitro transcription of polymerase chain reaction-generated templates incorporating bacteriophage T7 RNA polymerase promoter sequences in one of the priming oligonucleotides. After dot blotting target DNA samples on nitrocellulose and hybridization with the riboprobes, the RNA: DNA hybrids formed were detected by a simple immunoenzymic assay involving sequential reactions with an anti-RNA : DNA hybrid monoclonal antibody, anti-mouse Ig-peroxidase conjugate and chromogenic or chemiluminescent enzyme substrate solution. This multiplex riboprobe system targeting both chromosomal and plasma-borne sequences permitted detection of virulent Y. enterocolitica, regardless of plasmid loss during handling of cultures, and was unreactive with a virulent Y. enterocolitica, other Yersinia and other bacteria. This system resulted in a significant improvement in the limit of detection in comparison to that obtained with individual probes.

Adhesins, Bacterial↗

Multiplex polymerase chain reaction to detect toxigenic Vibrio cholerae and to biotype Vibrio cholerae O1.

A multiplex polymerase chain reaction (PCR) was developed to identify cholera toxin-producing Vibrio cholerae and to biotype V. cholerae O1. Enterotoxin-producing V. cholerae strains were identified with a primer pair that amplified a fragment of the ctxA2-B gene. Vibrio cholerae O1 strains were simultaneously differentiated into biotypes with three primers specified for the hylA gene in the same reaction. The hlyA amplicon in the multiplex PCR serves as an internal control when testing toxin-producing strains, as hlyA gene sequences exist in all tested V. cholerae strains. Enrichment of V. cholerae present on oysters for 6 h in alkaline peptone water before detection by a nested PCR with internal primers for ctxA2-B gene yielded a detection limit lower than 3 colony-forming units (cfu) per gram of food.

Animals↗

Differentiation between Mycobacterium tuberculosis and Mycobacterium bovis by a multiplex-polymerase chain reaction.

A multiplex-polymerase chain reaction (PCR) assay, based on one-step amplification and detection of three different mycobacterial genomic fragments, was designed for differentiation between Mycobacterium bovis and Mycobacterium tuberculosis. The oligonucleotide primers were chosen from the groEL gene, present in the genus Mycobacterium sp., from the IS6110 insertion sequence, present in Myco. tuberculosis complex and from the mtp40 gene, identified as a specific-species Myco. tuberculosis genomic fragment. This amplification method allowed the detection of two fragments of 576 and 317 base pairs in Myco. bovis and three fragments of 576, 396 and 317 base pairs in Myco. tuberculosis strains, including atypical strains of Myco. tuberculosis where the copy number of the IS6110 element is low. The multiplex-PCR assay described may be a very useful tool for the rapid and specific differentiation of these related mycobacteria and easy to use in medical and veterinary microbiology laboratories.

Base Sequence↗

Simultaneous detection of Macrobrachium rosenbergii nodavirus and extra small virus by a single tube, one-step multiplex RT-PCR assay.

Post-larvae of Macrobrachium rosenbergii infected with white tail disease were collected from hatcheries and nursery ponds in India. The causative organisms have been identified as Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV). A one-step multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) has been developed to detect these viruses simultaneously in naturally and experimentally infected prawns. Several parameters were assayed in order to optimize the protocol for simultaneous detection. Naturally and experimentally infected prawns showed two prominent bands of 681 and 500 bp for MrNV and XSV, respectively, as in separate RT-PCR assays. Experimentally infected adult prawns showed two bands for these two viruses in all the organs, except hepatopancreas and eyestalk, as seen in normal RT-PCR. The sensitivity test carried out on the primer sets of MrNV and XSV revealed that these primers could simultaneously detect the two viruses at a level of 25 fg of total RNA prepared from infected samples using this multiplex RT-PCR protocol.

Animals↗

Familial hypobetalipoproteinaemia complicated by cerebellar ataxia and steatocystoma multiplex.

A 55-year-old man with cerebellar ataxia and steatocystoma multiplex was found to have reduced serum concentrations of total cholesterol, betalipoprotein and apolipoprotein B. Computed tomography revealed atrophy of the cerebellum and brain stem. Of the six family members examined, four had hypobetalipoproteinaemia, and one had mild ataxia. Similar skin lesions were noted in five male relatives. This case represents a rare combination of familial hypobetalipoproteinaemia, cerebellar ataxia and steatocystoma multiplex.

Cerebellar Ataxia↗

Imaging orientational order and lipid density in multilamellar vesicles with multiplex CARS microscopy.

Multiplex coherent anti-Stokes Raman scattering (CARS) microscopy is used to measure the width of the orientational order distribution of lipid acyl chains within a three-dimensionally confined microscopic probing volume. A theoretical model is developed to describe and simulate the polarization-dependent measurements. We observe that the orientational order in phosphatidylcholine multilammellar vesicles increases significantly upon addition of small amounts (<or=15 mol%) of cholesterol and is significantly reduced for unsaturated lipids. Based on these measurements and using the quantitative nature of multiplex CARS microscopy the exact local concentration of lipid molecules within the vesicles can be measured in terms of the number of lipid bilayers present in the microscopic probing volume.

Lipids↗

Lymphangioma tuberosum multiplex: an unusual variant of lymphangioma.

Lymphangioma tuberosum multiplex is a variant of lymphangioma in which there is an abundant proliferation of endothelial cells and dilated lymphatic vessels forming a large, lobulated tumor. A 57-year-old black man developed lymphangioma tuberosum multiplex progressively over a 30-year period following the removal of a smaller tumor from the right posterior flank.

Humans↗

Suggestion for the treatment of steatocystoma multiplex located exclusively on the face.

BACKGROUND: Although there are numerous reports of different treatment methods, the long-term management of steatocystoma multiplex remains difficult. In this article we describe a simple technique that we used to treat the cysts on the face of a patient. METHODS: A 31-year-old male with steatocystoma multiplex located on the forehead and both temples was treated by inserting the tip of a needle and extirpating the contents, without removing the cyst wall. RESULTS: The procedure was very well tolerated by the patient. There have been no complications during or following the procedure. There were no recurrences after 10 months of follow up. CONCLUSIONS: We suggest that this very simple technique is worth trying as a treatment of choice, especially for the management of facial lesions, where scarring is unacceptable.

Adult↗

HLA and disease: haplotype sharing in multiplex families.

Recently it has been argued that the distribution of shared haplotypes in multiplex sibships for HLA-associated diseases may be an indicator of the disorder's underlying mode of transmission. Specifically, it has been suggested that the presence of multiple disease susceptibility genes and/or loci may be inferred when an inverse relationship between the amount of haplotype sharing and the number of affected sibs is observed in families where neither parent is affected. This claim is evaluated using extensive computer simulations. It is shown that a variety of haplotype sharing patterns are possible, even for the simplest models, and that for a large segment of the parameter space the actual distribution of shared haplotypes is opposite to that predicted. Accordingly, the inference that more than one locus is involved in the etiology of an HLA-associated non-Mendelian disease, if based only on the distribution of shared haplotypes in multiplex sibships, is unjustified.

Genetic Diseases, Inborn↗

A novel human leucocyte antigen-DRB1 genotyping method based on multiplex primer extension reactions.

We have developed and validated a semi-automated fluorescent method of genotyping human leucocyte antigen (HLA)-DRB1 alleles, HLA-DRB1*01-16, by multiplex primer extension reactions. This method is based on the extension of a primer that anneals immediately adjacent to the single-nucleotide polymorphism with fluorescent dideoxynucleotide triphosphates (minisequencing), followed by analysis on an ABI Prism 3700 capillary electrophoresis instrument. The validity of the method was confirmed by genotyping 261 individuals using both this method and polymerase chain reaction with sequence-specific primer (PCR-SSP) or sequencing and by demonstrating Mendelian inheritance of HLA-DRB1 alleles in families. Our method provides a rapid means of performing high-throughput HLA-DRB1 genotyping using only two PCR reactions followed by four multiplex primer extension reactions and PCR-SSP for some allele groups. In this article, we describe the method and discuss its advantages and limitations.

Alleles↗

Development of a multiplex PCR-SSP method for Killer-cell immunoglobulin-like receptor genotyping.

Killer-cell immunoglobulin-like receptors (KIRs) on natural killer (NK) cells recognize groups of HLA class I alleles. Recent work suggests that KIR genotype may affect the outcome of hematopoietic stem-cell transplants and that prospective KIR typing maybe of benefit in future matching of donors and recipients. A simple and informative KIR genotyping method was developed using a multiplex polymerase chain reaction-sequence-specific primer strategy. This method contains four multiplex reactions for detecting all functional KIR genes, including some 2DS4 variants that harbor a common deletion. Primer pairs were designed to provide short amplicons (108-565 bp) that can be analyzed by agarose gel electrophoreses or by automated electrophoretic systems. This method was evaluated in a blinded survey with the NK/KIR Phase II QC Panel (a total of 16 cell lines) from the 14th International Histocompatibility Workshop (IHWS), and the results are 100% concordant with the consensus genotype. Results in further KIR genotyping of 20 reference cell lines from the 10th IHWS were consistent with previously published genotypes, matching those of one study in instances where different genotypes have been previously reported. The genotypes obtained in this study may be helpful to other labs developing KIR genotyping methods in resolving typing discrepancies and in detecting common deletion variants of 2DS4. This method can save labor and reagent costs. It provides good results from partially degraded template DNA due to short amplicons in this method. It is convenient to use in both clinical and research laboratories.

DNA↗

Permanent neonatal diabetes with arthrogryposis multiplex congenita and neurogenic bladder - a new syndrome?

Neonatal diabetes mellitus is a rare (1/400 000 newborns) but potentially devastating condition, which may be transient or permanent; typical symptoms occur within the first 4 wk of life. The transient form is a developmental insulin production disorder that resolves postnatally. Fifty to 60% of cases can be seen as transient form. Cases that require lifelong insulin therapy can be described as permanent condition. This fraction of cases is less common than the transient form. There are no clinical features that can predict whether a neonate with diabetes mellitus but no other dysmorphology will eventually have permanent neonatal diabetes mellitus (PNDM) or transient neonatal diabetes mellitus. Some metabolic or genetic defects such as complete deficiency of glucokinase or heterozygous activating mutations of KCNJ11, encoding Kir6.2, were found in patients with PNDM. A preterm female infant with a gestational age of 36 wk was admitted to the neonatal intensive care unit in the first hours of life due to prematurity and intra-uterine growth retardation. She was diagnosed as having arthrogryposis multiplex congenita on the first day. Hyperglycemia was detected on the third day of life, and she required insulin treatment. The patient is now 6 yr old with PNDM, arthrogryposis multiplex, neurogenic bladder, immune deficiency, constipation, and ichthyosis. Is this a new form of neonatal diabetes mellitus?

Arthrogryposis↗

Detection and identification of food-borne pathogens of the genera Campylobacter, Arcobacter and Helicobacter by multiplex PCR in poultry and poultry products.

The objective of this study was to develop a multiplex polymerase chain reaction (PCR) to detect and differentiate food-borne pathogens of the three genera Campylobacter, Arcobacter and Helicobacter in a single step procedure. One common reverse primer and three genus-specific forward primers were designed by hybridizing to the 16S rRNA of selected reference strains. Besides the species with significance as food-borne pathogens isolated from poultry meat--Campylobacter jejuni, Campylobacter coli, Arcobacter butzleri and Helicobacter pullorum--several other members of these genera were tested to determine the specificity of the designed multiplex PCR. In total, 20 ATCC and NCTC reference strains of Campyobacter, Arcobacter and Helicobacter were used to evaluate the PCR. Specific amplificates were obtained from all thermophilic species of Campylobacter as well as from species of Arcobacter and Helicobacter. No amplification product was obtained from the non-thermophilic Campylobacter, C. hyointestinalis and C. fetus. Furthermore, a total of 43 field strains of the three genera isolated from poultry, pigs, cattle and humans were investigated using this PCR. To confirm the classification of 10 H. pullorum strains the 16S rRNAs were sequenced. The developed PCR is a helpful diagnostic tool to detect and differentiate Campylobacter, Arcobacter and Helicobacter isolated from poultry and poultry products.

Animals↗

Qualitative multiplex RT-PCR for simultaneous detection of hepatitis C virus and human immunodeficiency virus in plasma samples.

This report describes the development of a one-tube multiplex reverse transcriptase (RT)-PCR assay for the simultaneous detection of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) in plasma samples. The assay was evaluated with two panels of HCV- and HIV-1-positive samples, as well as negative plasma specimens. Extraction and amplification of HCV and HIV-1 RNA from plasma samples were performed in a single reaction, and amplified genomes were detected with specific probes. Serial dilutions of the HCV and HIV-1 first World Health Organization International Standards were used to evaluate the sensitivity of the method. Two RNA controls were constructed to determine inter-assay variations and the sensitivity of the amplification step. The assay had good specificity and detected all the genotypes and subtypes tested. The analytical sensitivity of the entire assay was 100 IU/mL for HCV and 200 IU/mL for HIV-1, while the amplification step detected ten copies/reaction for HCV and 20 copies/reaction for HIV-1. The multiplex assay allowed the simultaneous extraction, amplification and detection of two virus genomes, thereby providing an important practical advantage and an efficient approach for analysing individual and pooled plasma donations.

Feasibility Studies↗

Comparison of the BD Directigen Flu A+B Kit and the Abbott TestPack RSV with a multiplex RT-PCR ELISA for rapid detection of influenza viruses and respiratory syncytial virus.

The Directigen Flu A+B enzyme immunoassay and the Abbott TestPack RSV enzyme immunoassay were each compared with a multiplex RT-PCR ELISA by testing 635 nasopharyngeal aspirates collected from children aged < 16 years who had been hospitalised with acute respiratory tract infection during the epidemic season 2002-2003. In this study, the sensitivity of the Directigen Flu A+B assay was unacceptably low (29.3% and 10.0%, respectively) for the detection of influenza A and B viruses. The sensitivity of the Abbott TestPack RSV assay (77.4%) was acceptable and in agreement with the multiplex RT-PCR ELISA.

Enzyme-Linked Immunosorbent Assay↗

Rapid identification and differentiation of Saccharomyces cerevisiae, Saccharomyces bayanus and their hybrids by multiplex PCR.

AIMS: To develop a multiplex PCR assay for the specific identification and differentiation of Saccharomyces cerevisiae, S. bayanus and their hybrids. METHODS AND RESULTS: Two sets of primers with sequences complementary to the region YBR033w were used. A single amplicon of 1710 bp or 329 bp was obtained with species S. cerevisiae and S. bayanus, respectively, while the presence of both bands was observed in S. pastorianus because of its hybrid nature. Both amplification products were also obtained after amplification from DNA of several laboratory S. cerevisiae x S. bayanus hybrid strains. CONCLUSIONS: Multiplex PCR was optimized for the rapid and reliable identification of S. cerevisiae, S. bayanus and their hybrids. SIGNIFICANCE AND IMPACT OF THE STUDY: The procedure may be used for routine detection of the most common Saccharomyces sensu stricto yeasts involved in industrial fermentation processes, overcoming the problems of conventional techniques.

DNA, Fungal↗