Profiling of Urinary Creatinine and prostanoids
In this project, we use HPLC-UV for the rapid profiling of urinary creatinine and prostanoids. We have applied this method to study the impact of acute and chronic exercise on hypertension in African American men and women (mean age 57 yrs), thus establishing a therapeutic exercise regime that will be accommodated by patient populations.
Hypertension is a common disease amongst the African American population. Some studies have suggested that 35% of African Americans have hypertension. This accounts for 20% of their deaths in the United States - twice the percentage of deaths among whites from hypertension. Also, compared with white Americans, hypertension develops earlier in life and average blood pressures are much higher in African Americans. Inflammation is proven to be a mediator in the pathophysiology of diseases like atherosclerosis, Alzheimer’s, hypertension and rheumatoid arthritis. Development of analytical methods for determining and quantifying pro and anti-inflammatory biomarkers is the cornerstone of current research. Arachidonic acid (AA), an ω-6 polyunsaturated fatty acid undergoes enzymatic oxidation by COX-2 to give prostanoids which include prostaglandins (PGE2, PGD2 and PGF2), prostacyclin (PGI2) and thromboxane A2 (TXA2). AA can also undergo free radical peroxidation to produce a series of prostaglandin like compounds which are known as the isoprostanes. In particular, 8-isoprostane also known as 8-iso PGF2, the most abundant form of the F2 isoprostane is considered to be a marker of in vivo oxidative stress. There is an increase in the production of many of these lipid molecules during inflammation and oxidative stress.
It is also ideal to monitor the creatinine levels as the measurement is done in urine. Creatinine is formed by non enzymatic dehydration and loss of phosphate from creatine and creatine phosphate which are generally found in the muscle and blood. It is excreted through the kidney at a nearly constant rate. As a result, measurement of the creatinine levels in urine is considered to be a reliable marker in predicting the kidney function .Since the volume of urine does not remain constant, the concentration of the compounds in urine will vary. Because variations in absolute concentration depend on the level of hydration in a patient, the ratio of the prostanoids to creatinine provides a valid assessment of oxidative stress and inflammation.
Determination of Sex Hormones in Urine as a Profile of Biological Age
The aim of this study is to determine the link between the sex hormones and hypertension in pre, peri and post menopausal women. We have developed a HPLC-UV method for the separation of estriol, estradiol, estrone, testosterone, progesterone and their metabolites. This method is applied to determine the urinary hormone levels in pre, peri and post menopausal hypertensive women.
Hypertension is considered to be the leading cause of mortality among African American population especially women. According to the data from the NHLBI’s ARIC study over 42.6% of African American men and 46.6% of African American women were diagnosed with hypertension and the overall mortality rate of African American women due to hypertension in 2004 was around 40.9%. Men and postmenopausal women are known to have greater incidences of hypertension compared to premenopausal women. This suggests that the female sex hormones have an effect on blood pressure.Estrone (E1), estradiol (E2), estriol (E3) and progesterone are the main female sex hormones in the body. Out of all these, estrone is assumed to be the only one present in variable quantities in postmenopausal women. 2-hydroxyesterone (2-OHE1), 16α-hydroxyestrone (16α -OHE1),4- hydroxyestrone (4-OHE1) and 2-methoxyestrone (2-MeOE1) are the major metabolites of estrone. The ratio of 2-hydroxyesterone (2-OHE1) to 16α-hydroxyestrone (16α -OHE1) is considered to be an index of breast cancer risk .Testosterone is a steroid hormone from the androgen group which is present at much higher concentration in men than in women.
Evaluation of the oxidative metabolites of ω-6 and ω-3 fatty acids and their implication in the progression of cardiovascular diseases, hypertension, rheumatoid arthritis and work related musculoskeletal disorders.
It is our hypothesis that a profile of HETEs, DiHETES, EETs, PGs, TXs and the metabolites of EPA and DHA will provide an understanding of disease progression and can report on intervention strategies in treatment for cardiovascular disease, CVD and certain inflammatory conditions like RA and hypertension. We have developed an LC-ESI-MS method for the screening of 39 lipid biomarkers of inflammation
A mechanistic understanding of the inflammation process as it relates to the disease state and injury needs to be developed. Specifically, the role and modulation of inflammation needs to be assessed as well as the mechanism which produces oxidation of arachidonic acid. Gender and age also affect the level and nature of the inflammatory process. Eicosanoids are specific biomarkers for inflammation. Their biosynthesis from arachidonic acid, and related fatty acid molecules can be catalyzed by either lipoxygenases (LOX), COX-2 or P450 enzymes. Depending on the mechanism/pathway or parent molecule, different distributions of eicosanoids are found. The oxidation of arachidonic acid gives hydroxy eicosatetraenoic acids (HETEs), dihydroxy eicosatetraenoic acids (DiHETEs), epoxy eicosatetraenoic acids (EETs), and prostaglandins (PGs) and thromboxane (TX). The metabolites of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (the ω-3 fatty acids) along with the metabolites of AA regulate inflammation.
Design and Evaluation of New Materials for Liquid and Plastic Scintillation
Scintillation method is based on the transformation inside the detector of radiation energy into the energy of light, which is subsequently detected by photoemissive devices. Different types of energy are converted into light by luminophors in the form of single crystals, their solutions in organic solvents (i.e., liquid scintillators), and solid solutions in plastics (i.e., plastic scintillators).
The scintillation (fluorescence) process in a Plastic Scintillator includes the excitation of molecules in the solvent, followed by the emission of photons that are fully absorbed by molecules of the dissolved luminophor. One such plastic scintillator being studied is based on
Poly(methyl methacrylate) (PMMA) composition containing benzene-dithiolate metal complexes and tetraphenyl butadiene as luminescent admixture.
Plastic scintillators are an attractive choice if a suitable method of compensation for the drop in response at low photon energies can be developed. The addition of mostly organometallic compounds containing atoms leads to quenching and does not yield a flat energy response. Therefore, the production of composite scintillators consisting of a plastic scintillator base material incorporating some inorganic scintillator powder was investigated.
In this work, we related the preparation and optical properties in a polymeric waveguide doped with Tetraphenylbutadiene (TPB):[n-C4H9][Co(bdt)2] and TPB:[Li][Co(bdt)2] scintillator materials/wavelength shifters. The transparent doped PMMA film was characterized by Differential Scanning Calorimetry, Thermogravimetric Analysis, Transmission Electron Microscope and ATR-FTIR. Upon characterization of the scintillator composite, we will study the effect of luminophor/polymeric matrix chemical binding factor on the luminescence. We will also investigate the effect of the presence of the polymer and the efficiency of excited-state energy transfer between the metal complex and TPB molecules.
