No abstract

The sensitive telomeric repeat amplification protocol (TRAP) permits telomerase detection in mammalian cell and tissue extracts with very low telomerase activity levels. Unfortunately, conventional TRAP assays require complex post-amplification procedures, such as polyacrylamide gel electrophoresis and densitometry, to measure telomerase products. Therefore, a real-time quantitative TRAP assay (RQ-TRAP) was optimized in the present study and evaluated in comparison with a commercially available quantitative TRAP kit and by monitoring telomerase activity in human hepatocyte cultures, human hepatoma cell lines and telomerase reconstitution experiments. The novel real-time telomerase detection method has many advantages. Other than sample extraction and real-time cycling, no additional time-consuming steps have to be performed for telomerase quantification; reliable and linear telomerase quantification is possible down to single-cell dilutions without the interference of primer-dimer artifacts, and the costs are less. Moreover, the precision is similar to other amplification-based telomerase quantification assays and the results are comparable to data obtained with two commercially available assays. The closed-tube system reduces the risk of carryover contamination and supports high throughput. In conclusion, RQ-TRAP provides a new tool for the rapid and reliable quantification of telomerase activity.

No abstract

Supplemental Digital Content is available in the text

Beta-ketothiolase (T2) deficiency is an inherited disease of isoleucine and ketone body metabolism caused by mutations in the ACAT1 gene. Between 2005 and 2016, a total of 41 patients with T2 deficiency were identified at a medical center in northern Vietnam, with an estimated incidence of one in 190,000 newborns. Most patients manifested ketoacidotic episodes of varying severity between 6 and 18 months of age. Remarkably, 28% of patients showed high blood glucose levels (up to 23.3 mmol/L). Ketoacidotic episodes recurred in 43% of patients. The age of onset, frequency of episodes, and identified genotype did not affect patient outcomes that were generally favorable, with the exception of seven cases (five died and two had neurological sequelae). Custom-tailored acute and follow-up management was critical for a positive clinical outcome. Two null mutations, c.622C>T (p.Arg208*) and c.1006-1G>C (p.Val336fs), accounted for 66% and 19% of all identified ACAT1 mutant alleles, respectively. Most patients showed characteristic biochemical abnormalities. A newborn screening program could be expected to have a high yield in Vietnam. Investigation findings of haplotypes linked to the most common ACAT1 mutation (c.622C>T) are consistent with an ancient common founder of mutation-bearing chromosomes belonging to the Kinh ethnic population. The direct management and long-term follow-up of a large number of T2-deficient patients enabled us to study the natural history of this rare disease.