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Amplification Tests (amplification + test)

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Medical Sciences66%

Kinds of Amplification Tests

  • acid amplification test
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  • nucleic acid amplification test
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    PRESCRIBER, Issue 14 2007
    Article first published online: 19 OCT 200
    Studies suggest risk of bone loss with SSRIs Two cross-sectional studies have suggested the SSRI antidepressants may be associated with an increased risk of bone loss (Arch Intern Med 2007;167:1240,5 &1246,51). In 2722 older women (mean age 79) living in the community who were participating in the Study of Osteoporotic Fractures cohort study, use of SSRIs was associated with a significant increase in the rate of loss of hip bone density compared with nonusers(0.82 vs 0.47 per cent per year). The rate of loss among women taking a tricyclic antidepressant was also 0.47 per cent per year. Excluding women with more severe depression did not alter the findings. In 5995 men aged 65 or older taking an SSRI in another study, mean bone density was 3.9 per cent lower at the hip and 5.9 per cent lower in the lumbar spine compared with no use of antidepressants. Use of a tricyclic antidepressant or trazodone was not associated with increased bone loss. The authors comment that the degree of bone loss is comparable with that associated with corticosteroids. Serotonin transporters have been identified in osteoblasts and osteocytes. Risk of rare birth defects with SSRIs Two US case-control studies have found qualified evidence that use of SSRIs during the first trimester may be associated with a small increase in the risk of rare neonatal defects (N Engl J Med 2007;356:2675,83 & 2684,92). The Slone Epidemiology Center Birth Defects Study identified 9849 infants with birth defects and 5860 without and found no significant association between SSRI use overall and defects previously attributed to SSRIs (craniosynostosis, omphalocele or heart defects). There was some evidence that sertraline and paroxetine may cause specific defects, but this was based on few cases and the absolute risk remained low. The National Birth Defects Prevention Study identified 9622 infants with major birth defects and 4092 controls. There was no significant association with heart defects but the odds of anencephaly, craniosynostosis and omphalocele were each significantly increased by a factor of 2,3. The authors say the absolute risk remains small and their findings require confirmation. UK data do not support MI link with rosiglitazone An interim analysis of a UK clinical trial of rosiglitazone (Avandia) has found no evidence that it is associated with an increased risk of myocardial infarction (N Eng J Med 2007;357:28,38). A US meta-analysis (N Engl J Med 2007;356:2457,71) recently suggested that the odds of an MI or cardiovascular (CV) death in patients taking rosiglitazone were increased by 40,60 per cent compared with controls. The UK analysis of an ongoing nonblinded trial comparing rosiglitazone plus a sulphonylurea or metformin with sulphonylurea/metformin found no significant differences in the risk of MI or CV death. The risk of heart failure was doubled in patients taking rosiglitazone. The authors comment that, with a mean follow-up of 3.75 years, they had too few data to reach a conclusive finding. Switch piroxicam users to another NSAID The European Medicines Agency has advised prescribers to switch patients who are taking oral piroxicam to another NSAID. The advice follows a reappraisal of the safety of piroxicam when the 2006 review of all nonselective NSAIDs suggested it may be associated with increased risks of GI adverse effects and serious skin reactions. The advice does not apply to topical formulations. Piroxicam should not be prescribed for acute conditions and should not be first-choice for osteoarthritis, rheumatoid arthritis and ankylosing spondylitis. The maximum dose should be 20mg per day and treatment should be reviewed after 14 days. The MHRA states there is no need for urgent action; long-term treatment should be reviewed at the next routine appointment. OTC azithromycin? The MHRA is consulting on a request by a pharmaceutical company to reschedule azithromycin to pharmacy-only status for the treatment of known or suspected Chlamydia trachomatis infection in individuals aged 16 years or older. The applicant envisages supplies being made only when a nucleic acid amplification test (NAAT) is positive. Responses should be submitted to the MHRA (www.mhra.gov.uk) by 2 August. Computers can reduce prescribing errors Computerised prescribing reduces by two-thirds the rate of medication errors associated with handwritten prescriptions, a new review has found (Health Services Research 2007; online doi:10.1111/j.1475,6773. 2007.00751.x). There was some evidence that the risk of all errors, dose errors and adverse effects were reduced by computerisation. The greatest impact was seen in settings with very high error rates (>12 per cent) associated with handwritten prescriptions. However, the studies included produced heterogeneous results and the reduction in errors in prescribing for children was not statistically significant. Furthermore, computerisation did not reduce the rate of prescribing the wrong drug. Echinacea works for colds, new study finds The herbal remedy Echinacea does reduce the risk of catching a cold, according to a new metaanalysis (Lancet Infect Dis 2007;7:473,80). In 2006, a Cochrane review found insufficient evidence to support the benefits claimed for Echinacea. The new study, which additionally included experimentally-induced infections among the 14 trials analysed, found that Echinacea reduced the odds of catching a cold by about half and reduced the average duration of a cold by 1.4 days. Though inconclusive, the possibility of publication bias and heterogeneity between the trials could not be excluded. HRT may reduce cardiovascular risk after all A subgroup analysis of the Women's Health Initiative (WHI) suggests that HRT may reduce the risk of coronary heart disease if started soon after the menopause (N Engl J Med 2007;356:2591,602). The main analysis of WHI showed no cardiovascular benefit for HRT, a finding attributed to the relatively old mean age of participants (59). In the new analysis of 1064 women aged 50,59, HRT use was associated with a significant reduction in coronary artery calcification compared with nonuse, with greater effect associated with greater adherence. Reducing BP key to avoiding heart failure An angiotensin,II receptor blocker (ARB) is no better than other antihypertensives at avoiding the development of heart failure in individuals with hypertension, say US investigators (Lancet 2007;369:2079,87). Drugs that affect the renin-angiotensin system can reduce ventricular hypertrophy and may therefore prevent the development of heart failure in patients with hypertension. This study found similar improvements in diastolic function in 384 patients with hypertension and left ventricular dysfunction randomised to valsartan (Diovan) or placebo in addition to standard antihypertensive treatment for 38 weeks. The authors conclude that blood pressure reduction, not choice of drug, is the most important factor. Copyright © 2007 Wiley Interface Ltd [source]

    What is the optimal approach for using a direct amplification test in the routine diagnosis of pulmonary tuberculosis?

    RESPIROLOGY, Issue 4 2002
    A preliminary assessment
    Objective: The aim of this study was to determine the most appropriate strategy for the rapid diagnosis of pulmonary tuberculosis (PTB) using a nucleic acid amplification (NAA) test. Methodology: This was a prospective study of 128 adult patients in whom respiratory secretions were tested for Mycobacterium tuberculosis by the AMPLICOR assay. The basis for starting PTB treatment was noted for each patient. The optimal approach was determined by using Bayes' theorem to compare different combinations of pretest probability, smear results with the AMPLICOR test. Results: The incidence of PTB was 15.6%. In only one patient was treatment for PTB commenced because of a positive AMPLICOR result. The rest were managed according to the conventional approach which relied upon clinical judgment and direct smear. The optimal approach was to treat patients with high or intermediate pretest risk for PTB who returned positive AMPLICOR tests. The overall accuracies of the conventional approach, AMPLICOR test and optimal approach were 89.8, 95.3 and 96.1%, respectively. Conclusion: This small study suggests that NAA testing be limited to patients with high or intermediate pretest risk of PTB. In this group, positive results demand treatment while the management of those with negative results still relies on clinical judgment. [source]

    Guidelines for the laboratory diagnosis of trichomoniasis in East European countries

    JOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 10 2010
    M Domeika
    Abstract The laboratory diagnosis of sexually transmitted infections in many Eastern European countries remains suboptimal. The main objective of the present evidence-based guidelines is to provide comprehensive information regarding the laboratory diagnosis of infections caused by Trichomonas vaginalis in East European countries. In particular, the present guidelines recommend: (i) to encourage examination of the wet mounts of vaginal exudates, instead of stained smears, at all clinical settings; (ii) nucleic acid amplification tests (NAATs) or culture could be employed if no trichomonads are detected on microscopic examination of the wet preparation and there is a strong indication of infection and (iii) the use of NAATs is encouraged in screening, using non-invasive specimens, or high volume testing situations. In the absence of internationally recognized commercial NAAT systems, tests developed in-house should be validated using obtainable international standards and quality assured strictly. Individual East European countries may be required to make minor national adjustments to these guidelines as a result of lack of accessibility to some reagents or equipment, or laws in a specific country. [source]

    Isolation and characterization of 11 polymorphic microsatellite loci in the whitegirdled goby (Pterogobius zonoleucus) and cross-species amplification in the serpentine goby (P. elapoides)

    MOLECULAR ECOLOGY RESOURCES, Issue 2 2009
    K. NOHARA
    Abstract Eleven polymorphic microsatellite markers were developed from a (CA)n -enrichment library of the whitegirdled goby (Pterogobius zonoleucus). Polymorphism at these loci ranged from 2 to 12 alleles, and observed and expected heterozygosities from 0.05 to 0.90 and from 0.05 and 0.86, respectively. All loci conformed to Hardy,Weinberg equilibrium, with no significant linkage disequilibrium between all locus pairs. Cross-species amplification tests were successful in P. elapoides, and most loci were polymorphic. These microsatellite markers will be useful in further population genetic studies of both species. [source]

    Cross-species amplification tests and diversity analysis using 56 PCR markers in Dactylis glomerata and Lolium perenne

    MOLECULAR ECOLOGY RESOURCES, Issue 1 2009
    I. LITRICO
    Abstract We report results of cross-species amplification in Dactylis glomerata and Lolium perenne of 12 simple sequence repeats (SSRs) isolated from Lolium multiflorum×Festuca glaucescens, 42 SSRs from Festuca arundinacea and two sequence tagged sites from Oryza sativa. We compared the transferability and diversity between D. glomerata and L. perenne, which are important forage crops. While Nei's gene diversity values were equivalent in both species (from 0.14 to 0.92), the mean number of allele per locus was more important in D. glomerata than in L. perenne (5.45 vs. 4.50). These markers will be used for analysing population structure in grassland populations under agronomic practices. [source]

    Microsatellite DNA markers for the aphid parasitoid Lysiphlebus fabarum and their applicability to related species

    MOLECULAR ECOLOGY RESOURCES, Issue 6 2007
    CHRISTOPH SANDROCK
    Abstract The aphid parasitoid Lysiphlebus fabarum is suspected to form distinct, host-associated lineages and exhibits poorly understood variation in reproductive mode including thelytokous and arrhenotokous populations. As a tool to study these issues, we developed 11 polymorphic microsatellite markers. The observed number of alleles ranged from two to 35, and the observed heterozygosity ranged from 0.01 to 0.64. Cross-species amplification tests demonstrated their utility for several congeners, but revealed very limited applicability to more distantly related species. [source]

    Urogenital infections in reproductive medicine

    ANDROLOGIA, Issue 2 2008
    S. Dieterle
    Summary Urogenital infections with Chlamydia trachomatis belong to the most prevalent sexually-transmitted bacterial diseases. In women, they can cause chronic salpingitis with subsequent tubal infertility and ectopic pregnancies. In men, C. trachomatis can cause urethritis, prostatitis and epididymitis. Urogenital infections can be symptomatic or asymptomatic. Symptomatic urogenital infections might impair male fertility. In vitro, C. trachomatis affects sperm motility and viability. However, there is no clear evidence that asymptomatic urogenital infections have an adverse effect on male fertility. Because C. trachomatis can be sexually transmitted and lead to female infertility, it is also of significance in male infertility work-up. Because of their high sensitivity, nucleic acid amplification tests should be used to examine first-void urine specimens. Both partners should be treated. The role of Ureaplasma urealyticum in reproductive medicine has been discussed controversially. There is no evidence that U. urealyticum has a significant impact on female or male infertility. [source]

    Retesting and follow-up of first-catch urines from men yield variable results with three Chlamydia trachomatis nucleic acid amplification tests

    APMIS, Issue 11 2000
    SVEIN ARNE NordbØ
    First-catch urines from 276 asymptomatic male military recruits were screened by polymerase chain reaction for the detection of Chlamydia trachomatis. Eight initially positive specimens were retested by polymerase chain reaction, ligase chain reaction and transcription-mediated amplification. Urine specimens from six (2.2%) subjects were considered to contain C. trachomatis. However, retesting of serially collected urines from five of these six subjects using different nucleic acid amplification methods showed some discrepancy. This may have a major impact on the efficacy of screening programs for C trachomatis in low prevalence populations. [source]

    Temporal cytokine gene expression patterns in subjects with trachoma identify distinct conjunctival responses associated with infection

    CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2005
    N. Faal
    Summary Ocular chlamydial disease is clinically diagnosed by the appearance of characteristic inflammatory changes and development of lymphoid follicles in the conjunctiva. Nucleic acid amplification tests and relatively non-invasive methods of sampling the conjunctival surface can be used to quantify the expression of chlamydial and host genes. Using quantitative real-time polymerase chain reaction to detect the presence of Chlamydia trachomatis (CT) 16S rRNA and human interleukin (IL)-1,, IL-10, IL-12p40, interferon (IFN)-, and tumour necrosis factor (TNF)-, transcripts we examined the immune response at the conjunctival surface in a cohort of children living in a trachoma-endemic village in The Gambia. Elevated cytokine transcript levels were associated with the presence of CT 16S rRNA. Subclinical infection (CT infection without clinical signs of disease) elicited an immune response that is proinflammatory in nature, with elevations in the transcription of IL-1,, IFN-, and IL-12p40. Clinically apparent infections were associated with the elevation of mRNA for the multi-functional cytokine TNF-, (fibrotic, type 1 inflammatory and regulatory) and the counter regulatory cytokine, IL-10, in addition to the other proinflammatory cytokines. A positive correlation between IFN-, transcript levels and the amount of CT 16S rRNA expressed in conjunctiva was found. [source]