Applied Biosystems

About: Applied Biosystems is a based out in . It is known for research contribution in the topics: Mass spectrometry & Capillary electrophoresis. The organization has 1521 authors who have published 1579 publications receiving 285423 citations.

PNA fluorescent in situ hybridization for rapid microbiology and cytogenetic analysis.

Abstract: Hybridization-based assays for the detection of nucleic acids including in situ hybridization are increasingly being utilized in a wide variety of disciplines such as cytogenetics, microbiology, and histology. Generally in situ hybridization assays utilize either cloned genomic probes for the detection of DNA sequences or oligonucleotide probes for the detection of DNA or RNA sequences. Alternately, PNA probes are increasingly being utilized in a variety of in situ hybridization assays. The neutral backbone of the PNA molecule allows for the PNA probes to bind to DNA or RNA under low ionic strength conditions that will either disfavor reannealing of complimentary genomic sequences or are denaturing for RNA secondary structure but are favorable for PNA/DNA or PNA/RNA hybridization. For in situ hybridization assays these unique properties of PNA probes offer significant advantages that allow for the development of fast, simple, and robust assays (Figs. 14.1 and 14.2).

Axial ejection resolution in multipole mass spectrometers

Abstract: An improved method of operating a mass spectrometer having a linear ion trap wherein ions are axially ejected from the trap to a detector or subsequent mass analysis stage. The DC barrier field produced at the exit lens of the trap is scanned in conjunction with the scanning of other fields used to energize ions of select mass-to-charge ratios past the barrier field/exit lens. The technique can maximize the resolution obtainable from axial ejection over a wide mass range.

Maternal urine and serum steroid measurements to identify steroid sulfatase deficiency (STSD) in second trimester pregnancies.

Abstract: Objective To document the performance of second trimester maternal urine and serum steroid measurements for detecting fetal steroid sulfatase deficiency (STSD). Methods We studied detection rate and false positive rate (DR, FPR) of analytes in maternal urine [combinations of 16α-OH-dehydroepiandrosterone sulfate (16α-OH-DHEAS), 11β-hydroxyandrosterone, total estriol] and serum [combinations of 16α-OH-DHEAS, 11β-hydroxyandrosterone, total estriol, unconjugated estriol (uE3)]. Samples were obtained from pregnancies which were screen positive for Smith-Lemli-Opitz syndrome (SLOS). Results Among 1 079 301 pregnancies, 3083 (0.29%) were screen positive for SLOS. Urine and/or serum samples were available from 917 viable pregnancies with known gender. We assigned likelihood ratios (LRs) to steroid measurements from male fetuses with known STSD and unaffected female fetuses. An LR ≥ 100 was present in urine from 84 of 86 STSD pregnancies (98% DR, 95% CI 92–99), along with 0 of 198 pregnancies with normal female fetuses (0.0% FPR, CI 0–1.9). LRs were ≥ 100 in 4 of 129 female fetuses with major abnormalities (3% FPR). In maternal serum, steroid measurements performed less effectively, achieving a 71% DR for STSD at a 1.6% FPR. Conclusion Maternal urine steroid measurements are effective for detecting STSD, including those with point mutations and those with full deletions. Copyright © 2009 John Wiley & Sons, Ltd.