DNA analysis: Under the heat

Nature China ◽  
2007 ◽  
Author(s):  
Wei Zeng
Keyword(s):  
1996 ◽  
Vol 75 (03) ◽  
pp. 422-426 ◽  
Author(s):  
Paolo Simioni ◽  
Alberta Scudeller ◽  
Paolo Radossi ◽  
Sabrina Gavasso ◽  
Bruno Girolami ◽  
...  

SummaryTwo unrelated patients belonging to two Italian kindreds with a history of thrombotic manifestations were found to have a double heterozygous defect of factor V (F. V), namely type I quantitative F. V defect and F. V Leiden mutation. Although DNA analysis confirmed the presence of a heterozygous F. V Leiden mutation, the measurement of the responsiveness of patients plasma to addition of activated protein C (APC) gave results similar to those found in homozygous defects. It has been recently reported in a preliminary form that the coinheritance of heterozygous F. V Leiden mutation and type I quantitative F. V deficiency in three individuals belonging to the same family resulted in the so-called pseudo homozygous APC resistance with APC sensitivity ratio (APC-SR) typical of homozygous F. V Leiden mutation. In this study we report two new cases of pseudo homozygous APC resistance. Both patients experienced thrombotic manifestations. It is likely that the absence of normal F. V, instead of protecting from thrombotic risk due to heterozygous F. V Leiden mutation, increased the predisposition to thrombosis since the patients became, in fact, pseudo-homozygotes for APC resistance. DNA-analysis is the only way to genotype a patient and is strongly recommended to confirm a diagnosis of homozygous F. V Leiden mutation also in patients with the lowest values of APC-SR. It is to be hoped that no patient gets a diagnosis of homozygous F. V Leiden mutation based on the APC-resi-stance test, especially when the basal clotting tests, i.e., PT and aPTT; are borderline or slightly prolonged.


1995 ◽  
Vol 73 (05) ◽  
pp. 756-762 ◽  
Author(s):  
Yoshiaki Tomiyama ◽  
Hirokazu Kashiwagi ◽  
Satoru Kosugi ◽  
Masamichi Shiraga ◽  
Yoshio Kanayama ◽  
...  

SummaryWe analyzed the molecular genetic defect responsible for type I Glanzmann’s thrombasthenia in a Japanese patient. In an immunoblot assay using polyclonal anti-GPIIb-IIIa antibodies, some GPIIIa (15% of normal amount) could be detected in the patient’s platelets, whereas GPIIb could not (<2% of normal amount). Nucleotide sequence analysis of platelet GPIIb mRNA-derived polymerase chain reaction (PCR) products revealed that patient’s GPIIb cDNA had a 75-bp deletion in the 3’ boundary of exon 17 resulting in an in-frame deletion of 25 amino acids. DNA analysis and family study revealed that the patient was a compound heterozygote of two GPIIb gene defects. One allele derived from her father was not expressed in platelets, and the other allele derived from her mother had a 9644C → T mutation which was located at the position -3 of the splice donor junction of exon 17 and resulted in a termination codon (TGA). Moreover, quantitative analysis demonstrated that the amount of the abnormal GPIIb transcript in the patient’s platelets was markedly reduced. Thus, the C → T mutation resulting in the abnormal splicing of GPIIb transcript and the reduction in its amount is responsible for Glanzmann’s thrombasthenia.


1997 ◽  
Vol 77 (02) ◽  
pp. 252-257 ◽  
Author(s):  
Joan F Guasch ◽  
Ruud P M Lensen ◽  
Rogier M Bertina

SummaryResistance to activated protein C (APC), which is associated with the FV Leiden mutation in the large majority of the cases, is the most common genetic risk factor for thrombosis. Several laboratory tests have been developed to detect the APC-resistance phenotype. The result of the APC-resistance test (APC-sensitivity ratio, APC-SR) usually correlates well with the FV Leiden genotype, but recently some discrepancies have been reported. Some thrombosis patients that are heterozygous for FV Leiden show an APC-SR usually found only in homozygotes for the defect. Some of those patients proved to be compound heterozygotes for the FV Leiden mutation and for a type I quantitative factor V deficiency. We have investigated a thrombosis patient characterized by an APC-SR that would predict homozygosity for FV Leiden. DNA analysis showed that he was heterozygous for the mutation. Sequencing analysis of genomic DNA revealed that the patient also is heterozygous for a G5509→A substitution in exon 16 of the factor V gene. This mutation interferes with the correct splicing of intron 16 and leads to the presence of a null allele, which corresponds to the “non-FV Leiden” allele. The conjunction of these two defects in the patient apparently leads to the same phenotype as observed in homozygotes for the FV Leiden mutation.


1997 ◽  
Vol 77 (03) ◽  
pp. 436-439 ◽  
Author(s):  
Armando Tripodi ◽  
Barbara Negri ◽  
Rogier M Bertina ◽  
Pier Mannuccio Mannucci

SummaryThe factor V (FV) mutation Q506 that causes resistance to activated protein C (APC) is the genetic defect associated most frequently with venous thrombosis. The laboratory diagnosis can be made by DNA analysis or by clotting tests that measure the degree of prolongation of plasma clotting time upon addition of APC. Home-made and commercial methods are available but no comparative evaluation of their diagnostic efficacy has so far been reported. Eighty frozen coded plasma samples from carriers and non-carriers of the FV: Q506 mutation, diagnosed by DNA analysis, were sent to 8 experienced laboratories that were asked to analyze these samples in blind with their own APC resistance tests. The APTT methods were highly variable in their capacity to discriminate between carriers and non-carriers but this capacity increased dramatically when samples were diluted with FV-deficient plasma before analysis, bringing the sensitivity and specificity of these tests to 100%. The best discrimination was obtained with methods in which fibrin formation is triggered by the addition of activated factor X or Russell viper venom. In conclusion, this study provides evidence that some coagulation tests are able to distinguish carriers of the FV: Q506 mutation from non-carriers as well as the DNA test. They are inexpensive and easy to perform. Their use in large-scale clinical trials should be of help to determine the medical and economic benefits of screening healthy individuals for the mutation before they are exposed to such risk factors for venous thrombosis as surgery, pregnancy and oral contraceptives.


Author(s):  
Gabriela Soto Laveaga

In my brief response to Terence Keel’s essay “Race on Both Sides of the Razor,” I focus on something as pertinent as alleles and social construction: how we write history and how we memorialize the past. Current DNA analysis promises to remap our past and interrogate certainties that we have taken for granted. For the purposes of this commentary I call this displacing of known histories the epigenetics of memory. Just as environmental stimuli rouse epigenetic mechanisms to produce lasting change in behavior and neural function, the unearthing of forgotten bodies, forgotten lives, has a measurable effect on how we act and think and what we believe. The act of writing history, memorializing the lives of others, is a stimulus that reshapes who and what we are. We cannot disentangle the discussion about the social construction of race and biological determinism from the ways in which we have written—and must write going forward—about race. To the debate about social construction and biological variation we must add the heft of historical context, which allows us to place these two ideas in dialogue with each other. Consequently, before addressing the themes in Keel’s provocative opening essay and John Hartigan’s response, I speak about dead bodies—specifically, cemeteries for Black bodies. Three examples—one each from Atlanta, Georgia; Rio de Janeiro, Brazil; and Mexico—illustrate how dead bodies must enter our current debates about race, science, and social constructions. 


2006 ◽  
Vol 30 (3) ◽  
pp. 193-199
Author(s):  
Hironaga Kakoi ◽  
Masahiko Kurosawa ◽  
Hiroshi Tsuneki ◽  
Ikuko Kimura
Keyword(s):  

Author(s):  
V. M. Kosolapov ◽  
N. N. Kozlov ◽  
I. А. Klimenko ◽  
V. N. Zolotarev

The methods of genetic identification of forage crops varieties and forms have significant scientific and practical importance in breeding and seed multiplication, in protection of author’s rights. At the current moment molecular markers on the base of DNA-polymorphism have been applied widely for these aims. This analytical review examines the possibilities and the prospects of application the different DNA-analysis methods for assessment of forage crops genetic diversity and for development the molecular-genetic passports of breeding achievements. The objective estimation of varieties structure and presence impurities is a necessary condition for improving the methodical approaches in approbation of crops and for decision the problems of timely variety-seed renovation and its systematic replacement. The system of DNA markers that registered in genetic passport will enable to keep the initial genetic structure of variety and to maintain it in production process during long time without fluctuations of agronomic important characteristics and properties. This factor is especially valuable for development the primary seed multiplication.


Pathology ◽  
1993 ◽  
Vol 25 (2) ◽  
pp. 144-147 ◽  
Author(s):  
L. Moore ◽  
R.W. Byard ◽  
N.H. Bramwell

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