2005 SWBA Poster Abstracts

 

1.

 

Molecular Imaging By Macro, Quantitative Autoradioluminography

Paul Strzemienski , Eric Solon, Alfred Lordi , Peter King, and Ben Chien, Quest Pharmaceutical Services, 110 Executive Drive, Suite 7, Pencader Industrial Park, Newark, DE 19702

Autoradioluminography, which utilizes phosphor imaging technology, is a qualitative and quantitative molecular imaging techniques that has wide applications throughout the Sciences. These techniques provide the ability to localize chemical entities, which have been radiolabeled, in a variety of biological and non-biological test systems. This is widely used in the Pharmaceutical Sciences, where drug discovery and development compounds are labeled with 14C, 3H, and/or 125I and tissue concentrations are determined in rodent, dog and monkey whole-body preparations. However, the technique has wide applications throughout Science such as: Botany, Environmental Science, Agriculture, Entomology, Pest Control, Food Science, Materials Sciences, Neurobiology, Aquatic & Marine Biology, Toxicology, Biology, Molecular Biology, Veterinarian Drug Development, Reproduction. This poster will present some of the varied macro applications for this technique.

 

 

2.

 

Quantitative Whole-Body Autoradiography (QWBA) in DMPK: Preclinical PK

Rebmann NS , Huang Y and King SP, Sanofi-Aventis, Bridgewater , NJ

Quantitative Whole-Body Autoradiography (QWBA) is a procedure, which examines the tissue distribution of radiolabeled compounds in a variety of animal species. With the recent technological advances QWBA, WBA is the method of choice for tissue distribution work in pre-clinical drug development. This technique yields similar results in comparison to those obtained by excision of tissues, followed by combustion and liquid scintillation counting. The data can be used to predict human radiation exposure to 14C and 3H during mass balance studies where the human dosimetry values can be estimated. In addition to providing the basic information on tissue pharmacokinetics, routes of elimination and distribution through WBA, the following can be ascertained: formulation selection; brain and cerebrospinal fluid exposure; localization, concentrations and persistence of drug-derived radioactivity; the dispositional fate of radiolabeled compounds in the body; estimation of tissue pharmacokinetic parameters for a given compound; the ability to distinguish concentrations of radioactivity within specific regions of tissues and organs; detection of potential sites of drug accumulation; melanin binding; tumor penetration; placental transfer; the identification of tissues with large concentrations or long retention of radioactivity of particular interest to Pre-Clinical Safety or Toxicology, correlation of tissue affinity with the site of pharmacological action. WBA methodology can ascertain important information for drug discovery as well as drug development.

 

 

3.

 

Histologic Analysis of Whole-Body Sections Made Easy

Bernice Schiller, Instrumedics, Inc., 61 SOUTH STATE STREET HACKENSACK, NJ 07601 Online: www.instrumedics.com E-mail: info@instrumedics.com

It has become apparent that simplification of histologic methods will increase their use in the WBAR laboratory. The Macro Tape-Transfer System makes that possible. The system is described and the steps in the method outlined.

It is hoped that this information will take some of the mystery out of whole-body morphologic methodology so that its application to drug metabolism studies can begin to provide anwers to currently unanswered questions.

 

 

4.

 

Tape Transfer of Cryomacrotomy Sections Expands the Capabilities of Investigative Pathology Laboratories to Include Whole-Body Morphologic Techniques .

Bernice Schiller, Instrumedics, Inc., 61 SOUTH STATE STREET HACKENSACK , NJ 07601 ;Online: www.instrumedics.com E-mail: info@instrumedics.com

In the pharmaceutical industry cryotomy is primarily a tool used in determining biodistribution of radiolabeled compounds in rodents by whole-body autoradiography and phosphorimaging.

The Macro-Tape-Transfer System (MTTS) from Instrumedics, Inc expands the capabilities of investigative pathology laboratories to include whole-body morphologic techniques.

Some of the new possibilities include large-scale histochemistry, immunohistochemistry, in-situ hybridization and laser capture microdissection.

With the use of the MTTS we are able to produce high-quality slides for staining and microscopic imaging, which was previously hindered by the inability to transfer sections to slides.

Presented are examples from individual studies that demonstrate the potential utility of whole-body morphologic techniques.

The accompanying poster describes the MTTS method.

 

 

 

 

5.

 

Combined Tissue Distribution, Tissue Quantitation, and Metabolite Profiling Using QWBA, FSD and LC/MS/MS

 

Eric Solon , Alfred Lordi , Ling He , Lata Venkataragan, Yuan-Shek Chen , Helen Shen , Zamas Lam , Yongdong Zhu , Rick Hamler, and Benjamin M. Chien , Quest Pharmaceutical Services, Newark, Delaware

This study addressed tissue distribution, metabolic profile, metabolite identification, and tissue concentration of Paclitaxel (Taxol) and its metabolites by combining QWBA, FSD and LC/MS/MS in a single experimental protocol. Four rats were given a 1h IV infusion of Taxol at a dose of 48 mg/kg (40 m Ci/kg). One rat each was euthanized immediately at the end of infusion and at 4-h post infusion. A third rat died during dosing after receiving approximately ? of its dose, and a fourth rat was found dead at 17h after the end of infusion. All carcasses were flash-frozen, prepared for QWBA, and tissue sampling for FSD and LC/MS/MS. QWBA results provided tissue distribution information as total radioactivity. Liver, spleen, heart, lung, blood, bone marrow, muscle, kidney, urine, and feces, which had the highest concentrations of the radioactivity, were removed from the remaining frozen carcasses for further analyses. Metabolites were identified using LC/MS/MS coupled with FSD. Concentrations of the parent Taxol and its metabolites in each organ or sub-region were quantitated using LC-radiochromatography and QWBA. Quantitation of drug and metabolites were also accomplished using LC/MS/MS. This study demonstrated the advantage of QWBA as a powerful tool for elucidating the distribution of Taxol and its metabolites in all the tissues and sub-regions. Furthermore, the combination with FSD or LC/MS/MS, enabled the determination of parent and metabolite concentrations in specific target tissues. We are currently using this combined QWBA-LC/MS/MS-LC/FSD approach for both discovery and non-GLP studies.

 

 

 

6.

 

Multiple Imaging Mass Spectroscopy

Andrew Davis, Cameca Instruments, Inc.

The NanoSIMS instrument is a high performance secondary ion, mass spectrometer of the “microprobe” type. That is, the beam is highly focused, with normal incidence, and imaging is accomplished by scanning one of two ion beams in a raster pattern on the sample at normal incidence. Although the prototype instrument was dedicated to cellular biology, the Nanosims was introduced as commercial product just 3 years ago. Its immediate use was for astrophysics and cosmochemistry in the study of interplanetary dust particles and pre-solar grains. More recently, the application fields have expanded to molecular tagging for cancer drug research and in pharmacology, for drug and toxin localization. Being a SIMS tool, analysis and imaging of secondary ions (positive or negative charge) resulting in elemental, isotopic and ion-cluster characterization. This poster will highlight the many design features that make the NanoSIMS unique in its ability to acquire data at the micron and sub-micron scale, in multiple-imaging mode (parallel detection) with high transmission (sensitivity), high mass resolution and high lateral resolution combined. Sample prep issues will be discussed as well.

 

 

 

 

7.

 

The Use of WBARG to Study the Fate of Environmental Contaminants in Aquatic Organisms

Claude Rouleau, Ph.D., Maurice Lamontagne Institute, Quebec , Canada

 

Through WBARG is commonly used in the pharmaceutical industry, it has found little use in the study of the fate of chemicals known or suspected to have adverse effects on aquatic biota. One reason for this is likely the high cost of the instrumentation needed, making such equipment out of reach of most researchers working in the field of aquatic environmental studies. In the middle of the 1980’s, Prof. Hans Tjalve and other researchers at the Department of Pharmacology and Toxicology of the Swedish University of Agricultural Sciences in Uppsala began some work on the uptake of radiolabeled metals in fish, which led to the discovery of an unexpected route of uptake in this animal. It was found that radiolabeled metal ions such as 109Cd (II), 54Mn(II), and 203Hg(II) enter the nervous system of fish via water-exposed sensory organs, such as the olfactory system and lateral line receptors, and are subsequently transported directly to the brain by axonal transport, thus circumventing the blood-brain barrier which is normally impervious to inorganic metal ions. It would have been very difficult to observe this phenomenon by using classical dissection techniques because of the very small size and location of the anatomical structure labeled (the olfactory nerve is completely embedded in the cranium). This clearly showed the potential of WBARG to study the fate of metals and other environmental contaminates in aquatic biota. During the 1990’s, we successfully used WBARG to study the fate of metals [ 109Cd(II), 65Zn(II), 203Hg(II), 110mAg(I), 113Sn(IV)] and organometals (methyl-[ 302Hg]-mercury, tributyl-[ 113Sn]-tin) in a variety of freshwater and marine animals (mosquito larvae, trout, plaice, snow crab, starfish), in collaboration with Prof. Tjalve.

In 2000, we bought a Leica CM-3600 cryomicrotome and a Cyclone phosphor imager system. This equipment has been recently installed in a new facility, the Laboratory of Radioisotopic Techniques Applied to Environmental Sciences (LARATAES), a collaboration between Fisheries and Oceans Canada and Institut des Sciences de la mer de Rimouski (University of Quebec at Rimouski). We will present the work done since the acquisition of the WBARG equipment on the fate of a variety of contaminants (pesticides, organometals, metals) in small crustaceans, mollusks, fish, and amphibians, and will highlight some of the most interesting findings.