Ted J. Ognibene

Bio: Ted J. Ognibene is an academic researcher from Lawrence Livermore National Laboratory. The author has contributed to research in topics: Accelerator mass spectrometry & Mass spectrometry. The author has an hindex of 18, co-authored 49 publications receiving 1030 citations.

A high-throughput method for the conversion of CO2 obtained from biochemical samples to graphite in septa-sealed vials for quantification of 14C via accelerator mass spectrometry.

Abstract: The growth of accelerator mass spectrometry as a tool for quantitative isotope ratio analysis in the biosciences necessitates high-throughput sample preparation. A method has been developed to convert CO2 obtained from carbonaceous samples to solid graphite for highly sensitive and precise 14C quantification. Septa-sealed vials are used along with commercially available disposable materials, eliminating sample cross contamination, minimizing complex handling, and keeping per sample costs low. Samples containing between 0.25 and 10 mg of total carbon can be reduced to graphite in ∼4 h in routine operation. Approximately 150 samples per 8-h day can be prepared by a single technician.

Cancer chemoprevention: Evidence of a nonlinear dose response for the protective effects of resveratrol in humans and mice

Abstract: Resveratrol is widely promoted as a potential cancer chemopreventive agent, but a lack of information on the optimal dose prohibits rationally designed trials to assess efficacy. To challenge the assumption that "more is better," we compared the pharmacokinetics and activity of a dietary dose with an intake 200 times higher. The dose-response relationship for concentrations generated and the metabolite profile of [(14)C]-resveratrol in colorectal tissue of cancer patients helped us to define clinically achievable levels. In Apc(Min) mice (a model of colorectal carcinogenesis) that received a high-fat diet, the low resveratrol dose suppressed intestinal adenoma development more potently than did the higher dose. Efficacy correlated with activation of adenosine monophosphate-activated protein kinase (AMPK) and increased expression of the senescence marker p21. Nonlinear dose responses were observed for AMPK and mechanistic target of rapamycin (mTOR) signaling in mouse adenoma cells, culminating in autophagy and senescence. In human colorectal tissues exposed to low dietary concentrations of resveratrol ex vivo, we measured enhanced AMPK phosphorylation and autophagy. The expression of the cytoprotective NAD(P)H dehydrogenase, quinone 1 (NQO1) enzyme was also increased in tissues from cancer patients participating in our [(14)C]-resveratrol trial. These findings warrant a revision of developmental strategies for diet-derived agents designed to achieve cancer chemoprevention.

Detection of Adriamycin–DNA adducts by accelerator mass spectrometry at clinically relevant Adriamycin concentrations

Abstract: Limited sensitivity of existing assays has prevented investigation of whether Adriamycin-DNA adducts are involved in the anti-tumour potential of Adriamycin. Previous detection has achieved a sensitivity of a few Adriamycin-DNA adducts/10(4) bp DNA, but has required the use of supra-clinical drug concentrations. This work sought to measure Adriamycin-DNA adducts at sub-micromolar doses using accelerator mass spectrometry (AMS), a technique with origins in geochemistry for radiocarbon dating. We have used conditions previously validated (by less sensitive decay counting) to extract [(14)C]Adriamycin-DNA adducts from cells and adapted the methodology to AMS detection. Here we show the first direct evidence of Adriamycin-DNA adducts at clinically-relevant Adriamycin concentrations. [(14)C]Adriamycin treatment (25 nM) resulted in 4.4 +/- 1.0 adducts/10(7) bp ( approximately 1300 adducts/cell) in MCF-7 breast cancer cells, representing the best sensitivity and precision reported to date for the covalent binding of Adriamycin to DNA. The exceedingly sensitive nature of AMS has enabled over three orders of magnitude increased sensitivity of Adriamycin-DNA adduct detection and revealed adduct formation within an hour of drug treatment. This method has been shown to be highly reproducible for the measurement of Adriamycin-DNA adducts in tumour cells in culture and can now be applied to the detection of these adducts in human tissues.

Single sample extraction protocol for the quantification of NAD and NADH redox states in Saccharomyces cerevisiae

Abstract: A robust redox extraction protocol for quantitative and reproducible metabolite isolation and recovery has been developed for simultaneous measurement of nicotinamide adenine dinucleotide (NAD) and its reduced form, NADH, from Saccharomyces cerevisiae. Following culture in liquid media, yeast cells were harvested by centrifugation and then lysed under nonoxidizing conditions by bead blasting in ice-cold, nitrogen-saturated 50 mM ammonium acetate. To enable protein denaturation, ice cold nitrogen-saturated CH(3)CN/50 mM ammonium acetate (3:1 v/v) was added to the cell lysates. Chloroform extractions were performed on supernatants to remove organic solvent. Samples were lyophilized and resuspended in 50 mM ammonium acetate. NAD and NADH were separated by HPLC and quantified using UV-Vis absorbance detection. NAD and NADH levels were evaluated in yeast grown under normal (2% glucose) and calorie restricted (0.5% glucose) conditions. Results demonstrate that it is possible to perform a single preparation to reliably and robustly quantitate both NAD and NADH contents in the same sample. Robustness of the protocol suggests it will be (i) applicable to quantification of these metabolites in other cell cultures; and (ii) amenable to isotope labeling strategies to determine the relative contribution of specific metabolic pathways to total NAD and NADH levels in cell cultures.

The therapeutic potential of resveratrol: a review of clinical trials.

Abstract: Resveratrol is a nutraceutical with several therapeutic effects. It has been shown to mimic effects of caloric restriction, exert anti-inflammatory and anti-oxidative effects, and affect the initiation and progression of many diseases through several mechanisms. While there is a wealth of in vitro and in vivo evidence that resveratrol could be a promising therapeutic agent, clinical trials must confirm its potential. In this work, we reviewed the current clinical data available regarding the pharmacological action of resveratrol. Most of the clinical trials of resveratrol have focused on cancer, neurological disorders, cardiovascular diseases, diabetes, non-alcoholic fatty liver disease (NAFLD), and obesity. We found that for neurological disorders, cardiovascular diseases, and diabetes, the current clinical trials show that resveratrol was well tolerated and beneficially influenced disease biomarkers. However resveratrol had ambiguous and sometimes even detrimental effects in certain types of cancers and in NAFLD. In most of the clinical trials, the major obstacle presented was resveratrol’s poor bioavailability. Thus, this work provides useful considerations for the planning and design of future pre-clinical and clinical research on resveratrol.

The Role of Resveratrol in Cancer Therapy

Abstract: Natural product compounds have recently attracted significant attention from the scientific community for their potent effects against inflammation-driven diseases, including cancer. A significant amount of research, including preclinical, clinical, and epidemiological studies, has indicated that dietary consumption of polyphenols, found at high levels in cereals, pulses, vegetables, and fruits, may prevent the evolution of an array of diseases, including cancer. Cancer development is a carefully orchestrated progression where normal cells acquires mutations in their genetic makeup, which cause the cells to continuously grow, colonize, and metastasize to other organs such as the liver, lungs, colon, and brain. Compounds that modulate these oncogenic processes can be considered as potential anti-cancer agents that may ultimately make it to clinical application. Resveratrol, a natural stilbene and a non-flavonoid polyphenol, is a phytoestrogen that possesses anti-oxidant, anti-inflammatory, cardioprotective, and anti-cancer properties. It has been reported that resveratrol can reverse multidrug resistance in cancer cells, and, when used in combination with clinically used drugs, it can sensitize cancer cells to standard chemotherapeutic agents. Several novel analogs of resveratrol have been developed with improved anti-cancer activity, bioavailability, and pharmacokinetic profile. The current focus of this review is resveratrol's in vivo and in vitro effects in a variety of cancers, and intracellular molecular targets modulated by this polyphenol. This is also accompanied by a comprehensive update of the various clinical trials that have demonstrated it to be a promising therapeutic and chemopreventive agent.

Analysis of 200 food items for benzo[a]pyrene andestimation of its intake ίη an epidemiologic study

Abstract: Research Section Analysis of 200 food items for benzo[a]pyrene and estimation of its intake ίη an epidemiologic study* Ν. Kazerouni a,c,*, R. Sinha a, Che-Han Hsu b,l, Α. Greenberg b,2, Ν. Rothman a "Divi8ion οι CαncCl' Epiden1iology αnd Genetic8, ΝαΙίοnαl Cαncer In8titute, ΝαΙίοnαl Ιn8ιίΙιιΙα ο/' Heαlth, Eχeωtίve ΡΙαΖα South, RIl1 7033, 6120 Execι;tivc Blvd, Rockvillc, MD 20892, USA bDepαrtIl1ent οjΈnvίrοnΙl1entαl SciencC8, Cook c.Όllege, RLifger8 υnίνCI'8ίΙΥ, Nell' Bnln8\vicl(, NJ 08903, USA CDeΡαι'Ιn1ent οι ΡΓeνenιίve Medicine αnd BiOlneuiC8, Unij(JΓmed Scγvice8 υnίνcγ8ίΙγ οjΊlιe ΗeαΙιl1 S(:ienC'e8, 4301 Jone8 BI'i,!ge Roαd, BethC8dα, MD 20814-4799, USA Accepted 1 October 2000 Animal stιιdies have shown that dietary intake of benzo[α]pyrene (BaP), a polycyclic aromatic hydrocarbon (ΡΑΗ), canses increased levels of tumors at several sites, particιιlarly ίη the upper gastrointestinal tract. However, the role of dietary intake of BaP and cancer ίη humans is not clear. We CIeated a BaP database of selected food products that could be lίnl(ed to Food Frequency Qnestionnaires (FFQs) to estimate BaP intake. BaP levels were measnred for each food line-item (composite samples) which consisted of a variety of foods ίη a FFQ. Composite sample parts were derived from the Second National Health and Nutrition Examination Survey (NHANES Π) which represents the most common food items consumed by the general popιιlation. Meat samples were cooked by different techniqnes ίn controlled conditions, and by varions restanrants and fast-food chains. Non-meat products were purchased from the major national supermarket chains. The qnantities of BaP were measnred using a thin-Iayer chromatography (TLC)/spectrofluorometer technique and were highly coaelated with both BaP (radius = 0.99) and sum of carcinogenic ΡΑΗ (1'=0.98) measured by HPLC technique. We lίnl(ed ΟΙΙΓ database to the results from a FFQ and estimated the daily BaP intal

Intracellular coenzymes as natural biomarkers for metabolic activities and mitochondrial anomalies.

Abstract: Mitochondria play a pivotal role in energy metabolism, programmed cell death and oxidative stress. Mutated mitochondrial DNA in diseased cells compromises the structure of key enzyme complexes and, therefore, mitochondrial function, which leads to a myriad of health-related conditions such as cancer, neurodegenerative diseases, diabetes and aging. Early detection of mitochondrial and metabolic anomalies is an essential step towards effective diagnoses and therapeutic intervention. Reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) play important roles in a wide range of cellular oxidation-reduction reactions. Importantly, NADH and FAD are naturally fluorescent, which allows noninvasive imaging of metabolic activities of living cells and tissues. Furthermore, NADH and FAD autofluorescence, which can be excited using distinct wavelengths for complementary imaging methods and is sensitive to protein binding and local environment. This article highlights recent developments concerning intracellular NADH and FAD as potential biomarkers for metabolic and mitochondrial activities.