Blood Pharmacokinetics Imaging by Noninvasive Heart Fluorescence Tomography and Application to Kidney Glomerular Filtration Rate Assessment.

In mouse pharmacokinetic (PK) studies, current standard methods often require large numbers of animals to support collection of blood samples serially over a defined time range. We have developed and validated a noninvasive fluorescence molecular tomography (FMT) heart imaging approach for blood PK quantification that uses small numbers of mice and has the advantage of repeated, longitudinal live imaging. This method was validated using a variety of near infrared (NIR) fluorescent-labeled molecules, ranging in size from 1.

Fluorescence imaging of bombesin and transferrin receptor expression is comparable to 18F-FDG PET in early detection of sorafenib-induced changes in tumor metabolism.

Physical measurement of tumor volume reduction is the most commonly used approach to assess tumor progression and treatment efficacy in mouse tumor models. However, it is relatively insensitive, and often requires long treatment courses to achieve gross physical tumor destruction. As alternatives, several non-invasive imaging methods such as bioluminescence imaging (BLI), fluorescence imaging (FLI) and positron emission tomography (PET) have been developed for more accurate measurement.

Detection and quantification of enzymatically active prostate-specific antigen in vivo.

Assays for blood levels of prostate-specific antigen (PSA), performed in prostate cancer detection, measure mostly inactive/complexed PSA and do not provide information regarding enzymatically active PSA, which is biologically more relevant. Thus, we designed and synthesized an enzymatically cleavable peptide sequence labeled with near-infrared (NIR) fluorophores (ex/em 740/770  nm) and coupled it to a pharmacokinetic modifier designed to improve its plasma kinetics. In its native state, the agent, PSA750 FAST™ (PSA750), is optically quenched (>95%) and only becomes fluorescent upon cleavage by active PSA, yielding a significant increase in signal.

A fluorogenic near-infrared imaging agent for quantifying plasma and local tissue renin activity in vivo and ex vivo.

The renin-angiotensin system (RAS) is well studied for its regulation of blood pressure and fluid homeostasis, as well as for increased activity associated with a variety of diseases and conditions, including cardiovascular disease, diabetes, and kidney disease. The enzyme renin cleaves angiotensinogen to form angiotensin I (ANG I), which is further cleaved by angiotensin-converting enzyme to produce ANG II. Although ANG II is the main effector molecule of the RAS, renin is the rate-limiting enzyme, thus playing a pivotal role in regulating RAS activity in hypertension and organ injury processes.

Noninvasive in vivo quantification of neutrophil elastase activity in acute experimental mouse lung injury.

We developed a neutrophil elastase-specific near-infrared fluorescence imaging agent, which, combined with fluorescence molecular tomographic imaging, allowed us to detect and quantify neutrophil elastase activity in vivo, in real time, and noninvasively in an acute model of lung injury (ALI). Significantly higher fluorescent signal was quantified in mice with LPS/fMLP-induced ALI as compared to healthy controls, correlating with increases in the number of bronchoalveolar lavage cells, neutrophils, and elastase activity. The agent was significantly activated ex vivo in lung sections from ALI but not from control mice, and this activation was ablated by the specific inhibitor sivelestat.

Efficient use of the iron ortho-nitrophenylporphyrin chloride to mimic biological oxidations of dimethylaminoantipyrine.

Major metabolites of dimethylaminoantipyrine have been synthesized using iron ortho-nitrophenylporphyrin chloride as biomimetic catalyst. Reactivity of iron tetrakis-ortho-nitrophenylporphyrin chloride [Fe(TNO2PP)Cl] has been compared with iron tetrakis-pentafluorophenylporphyrin chloride and iron tetrakis-2,6-dichlorophenylporphyrin chloride using various oxidants such as hydrogen peroxide, iodosobenzene, and cumene hydroperoxide in either protic or aprotic solvent. Effect of imidazole has been showed on the reactivity of Fe(TNO2PP)Cl/cumene hydroperoxide system.

Expression, purification, and characterization of rat interferon-beta, and preparation of an N-terminally PEGylated form with improved pharmacokinetic parameters.

To identify potential new clinical uses and routes of administration for human interferon-beta-1a (IFN-beta-1a), we have developed an expression and purification procedure for the preparation of highly purified rat interferon-beta (IFN-beta) suitable for testing in rat models of human disease. An expression vector containing the rat IFN-beta signal sequence and structural gene was constructed and transfected into Chinese hamster ovary (CHO) cells. The protein was purified from CHO cell conditioned medium and purified to > 99.

Capillary electrophoresis/electrospray ion trap mass spectrometry for the analysis of negatively charged derivatized and underivatized glycans.

The increasing interest in the development of glycoproteins for therapeutic purposes has created a greater demand for methods to characterize the sugar moieties bound to them. Traditionally, released carbohydrates are derivatized using such methods as permethylation or fluorescent tagging prior to analysis by high performance liquid chromatography (HPLC), capillary electrophoresis (CE), or direct infusion mass spectrometry. However, little research has been performed using CE with on-line mass spectrometry (MS) detection.