Identification and validation of N-acetylputrescine in combination with non-canonical clinical features as a Parkinson's disease biomarker panel.

Parkinson's disease is a progressive neurodegenerative disorder in which loss of dopaminergic neurons in the substantia nigra results in a clinically heterogeneous group with variable motor and non-motor symptoms with a degree of misdiagnosis. Only 3-25% of sporadic Parkinson's patients present with genetic abnormalities that could represent a risk factor, thus environmental, metabolic, and other unknown causes contribute to the pathogenesis of Parkinson's disease, which highlights the critical need for biomarkers. In the present study, we prospectively collected and analyzed plasma samples from 194 Parkinson's disease patients and 197 age-matched non-diseased controls.

Multiplexed LC-MS/MS analysis of methylsuccinic acid, ethylmalonic acid, and glutaric acid in plasma and urine.

Low molecular-mass aliphatic carboxylic acids are critically important for intermediate metabolism and may serve as important biomarkers for metabolic homeostasis. Here in, we focused on multiplexed method development of aliphatic carboxylic analytes, including methylsuccinic acid (MSA), ethylmalonic acid (EMA), and glutaric acid (GA). Also assessed was their utility in a population's health as well as metabolic disease screening in both plasma and urine matrices.

Development and validation of an immunoassay for quantification of NCAM-1 in human plasma.

Background: Neural Cell Adhesion Molecule 1 (NCAM-1), a multifunctional member of the immunoglobulin superfamily, is expressed on the surface of neurons, glia, skeletal muscle, and natural killer cells. NCAM-1 has been implicated as having a role in cell-cell adhesion, involved in development of the nervous system, and for cells involved in the expansion of T cells and dendritic cells which play an important role in immune surveillance. Sensitive and specific methods to quantify non-surface bound NCAM-1 are not available.

A Simple Protein Precipitation-based Simultaneous Quantification of Lovastatin and Its Active Metabolite Lovastatin Acid in Human Plasma by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry using Polarity Switching.

Lovastatin is an anti-cholesterol lactone drug indicated for the treatment of hyperlipidemia and to reduce the risk of coronary heart disease. It is converted to the β-hydroxy acid form (lovastatin acid) , which is the major pharmacologically active metabolite. Here, we describe the development and validation of an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based method utilizing polarity switching for the simultaneous quantification of lovastatin and lovastatin acid in human plasma.

Ethnic variability in the expression of hepatic drug transporters: absolute quantification by an optimized targeted quantitative proteomic approach.

Hepatic OATPs 1B1, 1B3 and 2B1, as well as P-gp, play important roles in regulating liver uptake and biliary excretion of drugs. The intrinsic ethnic variability in OATP1B1-mediated hepatic uptake of statins has been proposed to underlie the ethnic variability in plasma exposures of statins between Caucasians and Asians. Using a targeted quantitative proteomic approach, we determined hepatic protein concentrations of OATP1B1, OATP1B3, OATP2B1, P-gp, and PMCA4 (a housekeeping protein) in a panel of human livers (n = 141) and compared protein expression across Caucasian, Asian, African-American, and unidentified donors.

A simple and sensitive assay for eflornithine quantification in rat brain using pre-column derivatization and UPLC-MS/MS detection.

Eflornithine (α-difluoromethylornithine) has been used to treat second-stage (or meningoencephalitic-stage) human African trypanosomiasis and currently is under clinical development for cancer prevention. In this study, a new ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based assay was developed and validated for the quantification of eflornithine in rat brain. To improve chromatographic retention and MS detection, eflornithine was derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate for 5 min at room temperature prior to injection.

Surface and superficial dose dosimetric verification for postmastectomy radiotherapy.

In patients given postmastectomy radiotherapy (PMRT), the chest wall is a very thin layer of soft tissue with a low-density lung tissue behind. Chest wall treated in this situation with a high-energy photon beam presents a high dosimetric uncertainty region for both calculation and measurement. The purpose of this study was to measure and to evaluate the surface and superficial doses for patients requiring PMRT with different treatment techniques.

Structure-based design of novel benzoxazinorifamycins with potent binding affinity to wild-type and rifampin-resistant mutant Mycobacterium tuberculosis RNA polymerases.

By utilization of three-dimensional structure information of rifamycins bound to RNA polymerase (RNAP) and the human pregnane X receptor (hPXR), representative examples (2b-d) of a novel subclass of benzoxazinorifamycins have been synthesized. Relative to rifalazil (2a), these analogues generally display superior affinity toward wild-type and Rif-resistant mutants of the Mycobacterium tuberculosis RNAP but lowered antitubercular activity in cell culture under both aerobic and anaerobic conditions. Lowered affinity toward hPXR for some of the analogues is also observed, suggesting a potential for reduced Cyp450 induction activity.

Dosimetric verification of surface and superficial doses for head and neck IMRT with different PTV shrinkage margins.

Purpose: Dosimetric uncertainty in the surface and superficial regions is still a major concern for radiation therapy and becomes more important when using the inverse planning algorithm for IMRT. The purpose of this study was to measure dose distributions and to evaluate the calculation accuracy in the superficial region for different planning target volume (PTV) shrinkage methods for head and neck IMRT plans.

Methods: A spherical polystyrene phantom 160 mm in diameter (ball phantom) was used to simulate the shape of the head.

Dosimetry of a novel rotating gamma system for stereotactic radiosurgery.

This is the first report of the basic dosimetric properties of a new rotating gamma system: the RGS Vertex360. Dosimetric properties were compared to those measured with traditional rotating gamma systems and with the Leksell Gamma Knife. The RGS Vertex360 is similar to the original rotating gamma system developed by OUR New Medical Technology Development Co.

Unexpected hormonal activity of a catechol equine estrogen metabolite reveals reversible glutathione conjugation.

4-Hydroxyequilenin (4-OHEN) is a major phase I metabolite of the equine estrogens present in widely prescribed hormone replacement formulations. 4-OHEN is autoxidized to an electrophilic o-quinone that has been shown to redox cycle, generating ROS, and to covalently modify proteins and DNA and thus potentially to act as a chemical carcinogen. To establish the ability of 4-OHEN to act as a hormonal carcinogen at the estrogen receptor (ER), estrogen responsive gene expression and proliferation were studied in ER(+) breast cancer cells.

Redox cycling of catechol estrogens generating apurinic/apyrimidinic sites and 8-oxo-deoxyguanosine via reactive oxygen species differentiates equine and human estrogens.

Metabolic activation of estrogens to catechols and further oxidation to highly reactive o-quinones generates DNA damage including apurinic/apyrimidinic (AP) sites. 4-Hydroxyequilenin (4-OHEN) is the major catechol metabolite of equine estrogens present in estrogen replacement formulations, known to cause DNA strand breaks, oxidized bases, and stable and depurinating adducts. However, the direct formation of AP sites by 4-OHEN has not been characterized.

Selective estrogen receptor modulator delivery of quinone warheads to DNA triggering apoptosis in breast cancer cells.

Estrogen exposure is a risk factor for breast cancer, and estrogen oxidative metabolites have been implicated in chemical carcinogenesis. Oxidation of the catechol metabolite of estrone (4-OHE) and the beta-naphthohydroquinone metabolite of equilenin (4-OHEN) gives o-quinones that produce ROS and damage DNA by adduction and oxidation. To differentiate hormonal and chemical carcinogensis pathways in estrogen receptor positive ER(+) cells, catechol or beta-naphthohydroquinone warheads were conjugated to the selective estrogen receptor modulator (SERM) desmethylarzoxifene (DMA).

Development of improved free-air ionisation chamber as absolute dosimetry standard for low-energy X rays in INER.

The National Radiation Standard Laboratory of the Institute of Nuclear Energy Research (INER) designed and constructed an improved Attix style free-air ionisation chamber (FAC) for low-energy X-ray measurements. Clinically, X rays in this energy range are used in mammography radiology. This chamber is also used to perform air-kerma measurements.

Estrogen Receptor {alpha} Enhances the Rate of Oxidative DNA Damage by Targeting an Equine Estrogen Catechol Metabolite to the Nucleus.

Exposure to estrogens increases the risk of breast and endometrial cancer. It is proposed that the estrogen receptor (ER) may contribute to estrogen carcinogenesis by transduction of the hormonal signal and as a "Trojan horse" concentrating genotoxic estrogen metabolites in the nucleus to complex with DNA, enhancing DNA damage. 4-Hydroxyequilenin (4-OHEN), the major catechol metabolite of equine estrogens present in estrogen replacement formulations, autoxidizes to a redox-cycling quinone that has been shown to cause DNA damage.

Estrogenic activity of the equine estrogen metabolite, 4-methoxyequilenin.

Oxidative metabolism of estrogens has been associated with genotoxicity. O-methylation of catechol estrogens is considered as a protective mechanism. 4-Methoxyequilenin (4-MeOEN) is the O-methylated product of 4-hydroxyequilenin (4-OHEN).

Structure-activity relationships for a family of benzothiophene selective estrogen receptor modulators including raloxifene and arzoxifene.

The search for the "ideal" selective estrogen receptor modulator (SERM) as a substitute for hormone replacement therapy (HRT) or use in cancer chemoprevention has focused on optimization of estrogen receptor (ER) ligand binding. Based on the clinical and preclinical benzothiophene SERMs, raloxifene and arzoxifene, a family of SERMs has been developed to modulate activity and oxidative lability. Antiestrogenic potency measured in human endometrial and breast cancer cells, and ER ligand binding data were correlated and seen to provide a guide to SERM design only when viewed in toto.

Activation of estrogen receptor-mediated gene transcription by the equine estrogen metabolite, 4-methoxyequilenin, in human breast cancer cells.

4-Methoxyequilenin (4-MeOEN) is an O-methylated metabolite in equine estrogen metabolism. O-methylation of catechol estrogens is considered as a protective mechanism; however, comparison of the properties of 4-MeOEN with estradiol (E(2)) in human breast cancer cells showed that 4-MeOEN is a proliferative, estrogenic agent that may contribute to carcinogenesis. 4-MeOEN results from O-methylation of 4-hydroxyequilenin, a major catechol metabolite of the equine estrogens present in hormone replacement therapeutics, which causes DNA damage via quinone formation, raising the possibility of synergistic hormonal and chemical carcinogenesis.