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Medical biotechnology
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
The first methods for finding out genetics used for DNA profiling involved restriction enzyme digestion, followed by Southern blot analysis. Although polymorphisms can exist in the restriction enzyme cleavage sites, more commonly the enzymes and DNA probes were used to analyze VNTR loci. However, the Southern blot technique is laborious and requires large amounts of undegraded sample DNA. In addition, Karl Brown’s original technique looked at many minisatellite loci at the same time, increasing the observed variability, but making it hard to discern individual alleles (and thereby precluding parental testing). These early techniques have been supplanted by polymerase chain reaction (PCR)-based assays.
Developing mitochondrial DNA field-compatible tests
Published in Critical Reviews in Environmental Science and Technology, 2022
Bidhan C. Dhar, Christina E. Roche, Jay F. Levine
Mitochondrial DNA genes are useful targets for polymerase chain reaction (PCR) assay development. Numerous nucleic acid based molecular techniques such as ribotyping, length heterogeneity PCR, terminal-restriction fragment length polymorphism, pulsed-field gel electrophoresis, amplified fragment length polymorphism, and southern blot analysis have their value for mtDNA detection but are tedious and dependent on expensive laboratory technology (Simpson et al., 2002). Several groups have developed microarray chip-based assays for mitochondrial and nuclear DNA detection (Dhar et al., 2015; Erdogan et al., 2001; Maitra et al., 2004; Vuong et al., 2013). These assays, however, require access to traditional laboratory instrumentation such as centrifuges and thermo-cyclers. Access to the needed instrumentation and laboratory infrastructure to take advantage of these technologies is often limited in developing countries, making the technologies inaccessible in many resource-constrained nations (Jani et al., 2014; Spooner et al., 2019). Skilled specimen collection and a secure, reliable framework for sample preservation and cold storage during transport is also needed and further limits the use of laboratory dependent technologies in economically challenged or remote communities. On-site sample-to-detection molecular assays are needed to accommodate fast and inexpensive environmental monitoring without expensive laboratory infrastructure, highly skilled staff, or cold storage.
Cardiorespiratory fitness and telomere length: a systematic review
Published in Journal of Sports Sciences, 2020
Adilson Marques, Élvio Rubio Gouveira, Miguel Peralta, João Martins, Joed Venturini, Duarte Henriques-Neto, Hugo Sarmento
Table 1 summarizes the study’s characteristics. The review of 20 studies accounts for 9705 subjects, and research was predominantly from the United States of America (7 studies), and Europe (6 studies). The rest of the studies were from Australia (3 studies), Brazil (2 studies), South Africa (1 study), and South Korea (1 study). Among the studies, 13 were cross-sectional, observational and comparative studies, four were randomized control trials (RCT), two were cross-sectional observational, and one was cross-sectional and prospective. The most frequent method to assess TL was polymerase chain reaction (PCR) (12/20), followed by Southern blot (3/20), flow–fluorescence in situ hybridization (FISH) (2/20), terminal restriction fragment (TRF) (1/20), fluorescein isothiocyanate (FITC) (1/20), and repeat copy number/single-gene copy number (1/20). The most frequent method used to evaluate cardiorespiratory fitness or training load was through a maximal graded treadmill or cycle ergometer test to estimate VO2 max consumption. However, some studies did not assess objectively the cardiorespiratory fitness level because the subjects were experienced endurance athletes (e.g. ultramarathon runners, runners who run ≥40 km/week).
Leukocyte telomere length and mortality among U.S. adults: Effect modification by physical activity behaviour
Published in Journal of Sports Sciences, 2018
Paul D. Loprinzi, Jeremy P. Loenneke
As noted in the introduction section, the previous studies examining the relationship between LTL and mortality are mixed, with the majority of studies, however, demonstrating that shorter LTL is associated with premature all-cause and cause-specific mortality. The mixed findings in the literature may be a result of several factors, including differences in measurement methods for LTL (e.g., Southern blot vs. quantitative PCR), modelling differences with regard to the covariates included in the analyses, and different populations for whom the LTL-mortality relationship was examined. With regard to modelling differences, most of the studies were minimally adjusted, typically only accounting for age, and occasionally gender or race–ethnicity (Sanders & Newman, 2013). However, in the literature, age, gender, and race–ethnicity are the only parameters consistently associated with LTL (Sanders & Newman, 2013). This is in accordance with our findings in that, beyond age, gender, and race–ethnicity, the addition of other covariates accounted for only 13% of the total effect between LTL tertile 3 versus 1 on all-cause mortality. In addition to studies examining the relationship between LTL and mortality among various populations (e.g., cancer survivors, chronic kidney disease patients), mixed findings may also be a result of minimal variability in LTL in the studies among only older adults (i.e., without a wide age range, a floor/ceiling effect may be present) (Sanders & Newman, 2013).