Geometric Mean Serum Cotinine Concentrations Confirm a Continued Decline in Secondhand Smoke Exposure among U.S. Nonsmokers-NHANES 2003 to 2018.

The objective of this study was to examine long-term trends in serum cotinine (COT) concentrations, as a measure of secondhand smoke (SHS) exposure, in U.S. nonsmokers using data from the National Health and Nutrition Examination Surveys (NHANES) from 2003 to 2018.

Nanoparticle-linked antagonist for leptin signaling inhibition in breast cancer.

Aim: To develop a leptin peptide receptor antagonist linked to nanoparticles and determine its effect on viability of breast cancer cells.

Methods: The leptin antagonist, LPrA2, was coupled EDAC [1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide] to iron oxide nanoparticles (IONP-LPrA2) to increase its efficacy. IONP-LPrA2 conjugation was confirmed by Western blot and nanoparticle tracking analysis.

Leptin-Notch signaling axis is involved in pancreatic cancer progression.

Pancreatic cancer (PC) shows a high death rate. PC incidence and prognosis are affected by obesity, a pandemic characterized by high levels of leptin. Notch is upregulated by leptin in breast cancer.

Obesity induced a leptin-Notch signaling axis in breast cancer.

To investigate whether obesity induces a leptin-Notch signaling axis in breast cancer (BC), leptin-induced Notch was determined in human MCF-7 and MDA-MB231 and mouse E0771 cells and in E0771-BC hosted by syngeneic lean and diet-induced obesity (DIO) C57BL/6J female mice. Lean and DIO mice were treated for 3 weeks with leptin inhibitor (PEG-LPrA2) 1 week after the inoculation of E0771 cells. Leptin induced Notch1, 3 and 4 in BC cells, but Notch2 expression showed opposite pattern in MCF-7 compared to MDA-MB231 cells.

Simultaneous determination of multiple drugs of abuse and relevant metabolites in urine by LC-MS-MS.

A method was developed for the quantitative analysis of 30 drugs of abuse and their metabolites in urine, including opiates, barbiturates, amphetamines, cocaine, cannabinoids, phencyclidine, methadone, and benzodiazepines. This method uses solid-phase extraction (SPE) on an Oasis HLB column followed by liquid chromatography-tandem mass spectrometry. Analytes were quantified by multiple reaction monitoring with the deuterated analogues as internal standards, using an atmospheric pressure ionization-electrospray interface.

Use of continine immunoassay test strips for preclassifying urine samples from smokers and nonsmokers prior to analysis by LC-MS-MS.

Cotinine biomarker measurements involving both smokers and nonsmokers must accommodate a broad range of concentrations. Thus, we have routinely preclassified unknown samples as being either "high" or "low" by using an enzyme-linked immunoassay for cotinine prior to analysis by tandem mass spectrometry (MS). Although this method is effective, it is also time-consuming and complex; a simpler and faster approach would be useful.