Saturday
Jul202013

A New Use for FDG

Hello!

My name is Stephanie Threatt, and I am one of the four summer interns in the Hooker Group this summer. The projects of the summer interns span from computational data analysis of PET images to chemically synthesizing molecules to be used for PET imaging. I’m on the synthetic chemistry side, and lets just say, it can be a challenge.

The basis of my project is to utilize Fluorodeoxyglucose (FDG), which is a commonly used and synthesized radiolabeled molecule that resembles glucose, to eventually label proteins and amino acids. Labeling proteins is currently quite difficult because most radiochemical reactions require very harsh conditions, which would denature the proteins.

My mentor, Changning, and I have basically approached my project with two main steps.  1) Synthesizing fluoromalondialdehyde (FMDA) from FDG via an oxidation reaction and 2) Verifying the ability of FMDA to react and label an amino acid/protein.

I finally figured out the first step of my project a few weeks ago, and this was pretty exciting progress because the reaction method to form FMDA was not only fast but quite simple. I use periodic acid (H5IO6) to oxidize FDG into FMDA, with formic acid and formaldehyde as by products. For the reaction to go to completion, I simply mix FDG and periodic acid in water for 1 minute at room temperature.

Since we were able to confirm the synthesis of FMDA via NMR, we proceeded to the next step of my project. A commonly used research tool for reactions involving heavier, more complex molecules is called Liquid chromatography- Mass spectrometry (LCMS). Using the molecular weight of your product and it’s UV activity, you can determine if your product if being properly formed.

My mentor and I found that the excess periodic acid used to make FMDA was hindering the molecules ability to react with our chosen amino acid, arginine. Therefore, we tried various methods of quenching periodic acid, such as glycol, methanol and even glucose. After several reactions, which were analyzed using LCMS, we were able to determine that glucose successfully quenched periodic acid, rendering it unreactive so that the FMDA-arginine reaction could proceed. Additionally, the need for HCl needed to be evaluated because arginine will only react with FMDA if it is properly protonated.

Determining the appropriate conditions in which to synthesize FMDA and react FMDA with arginine in the presence of formic acid, formaldehyde and periodic acid was quite challenging, but yesterday I collected some very promising data using LCMS. Though I will need to confirm the results by repeating the experiment, I am very hopeful that I may have found good conditions to complete both steps of my project, and if so, I will move to using “hot” 18FDG, which will be really exciting.

I’ll be sure to keep the blog updated with my progress, and thanks for reading! Everyone in the Hooker Group does such fascinating research, so I urge you to keep reading!

 

-Stephanie T.

Saturday
Jul132013

A sweet adventure!

 

I guess everybody has a different story how he/she joins the Hooker group. Through my entire PhD, I was working on hard-core organic synthesis. Every day, I struggled to get better yield and ee for a new methodology and I really enjoyed it. When looking for a postdoc, I decided to apply for those groups where my chemistry skills would be expanded beyond just organic chemistry. 

Then I was introduced to Jacob and joined the Hooker group.   The past couple of months has been a really sweet adventure for me - radiochemistry, automation, radiotracer development......I was and am learning new things every day. The project is very exciting - it is really solving a problem, not just a publication (Nothing wrong with publications. I love to publish!). For the FIRST time, I see the translational power of chemistry. And for the first time, I see the practical use of my chemistry! The group is very diverse; we have experts on neuroscience, on radiochemistry, on PET imaging, of couse on organic synthesis :)-...... And group members are awesome!!!! The woking philosophy-efficiency matters the most-makes the working environment so pleasant! 

Hong :)-

 

Saturday
Jul132013

History of Neuroscience

If you have not come across the YouTube video series "History of Neuroscience" I encorouge you to take a look.  I just finished watching the video by Louis Sokoloff , which I highly recommend for anyone to watch who does FDG-PET imaging.  At some point, I will try and blog about how important the 2DG and later FDG methods have been for neuroscience.  For me, it was an honor to train with Joanna Fowler at Brookhaven National Lab (where FDG was invented) and such a delight to continue working with Joanna on projects in my current position.  I'm inspired by how one molecule developed by chemists can have such a profound influence on knowledge.  I was drawn to PET imaging as a chemist because of the translational power that PET provides a chemist for studying living human beings.  I'm proud to have a research group that is diverse but is rooted in chemistry.  I have the pleasure of working with and training incredible neuroscientists, biologists, biochemists, and chemists.  I hope that through blogging, our group will convey the types of research problems that we find exciting and what it is like to work with us.

Monday
Jul082013

Exciting Things Happening In the Hooker Lab!

Greetings! This post is aimed at giving everyone who visits this group website a more behind the scenes view on what takes place on a day-to-day basis in the Hooker lab. There is a great diversity in this lab, so every day there is something new and exciting going on. Here is a preview as to what some of our group members will be doing this week:

Misha: Running Western blots on rat brain tissue from animals treated 
with novel radioprobes; Analyzing immunohistochemical data from rat 
brain tissue, and reconstructing PET images collected for a clinical study 
investigating chronic pain.

Nicole -  I am currently finishing a response to the IRB based on elements from an exciting Autism kick-off meeting on Monday as well as working on a review, while attenuation maps for an MR/PET study are running in the background. I also spent some time trouble-shooting the lab computer.

Marjorie: "The matlab week!"
I'm currently processing PET-MR data using a mix of tools from FSL, 
FreeSurfer, SPM and my own matlab codes. I'm proud of my first 
FreeSurfer-derived ROI to process our dynamic PET images!

Al Schroeder;
1. rat brain protein analysis (Does our new inhibitor predictably 
suppress enzyme activity?)
2. human brain PET imaging analysis (Using small regions of interest, 
can we gain insight into how an anesthetic drug works?)
3. switching desks (Can I swing my arms around freely and NOT hit 
anyone?)
4. contributing to the blog (Will posting increase my street cred?)

Stephanie Lie - Building and performing parametric map analysis of the group's past non-human primate fMRI studies of the brain utilizing a variety of pharmacological challenges. 

William Taylor- improving yield and purfication methods for the Palladum-catalyzed Suzuki cross coupling reaction.

These are just a few examples of the exciting and diverse research that takes place all right here in the Hooker lab. We will continue to keep this blog updated with new intriguing details on what will be happening next, as well as any interesting news or results that may be found in this lab. 

Monday
Jul082013

Progress Update

Hello all who are reading this. This is William checking in to give an update on my progress, as I know I have not written a blog in a while now. As a part of my project I have to go through a series of organic synthesis steps in order to yield the final product that I will be using to analyze the brain via autoradiography. There is one reaction in the middle of the synthesis known as the Palladium-catalyzed Suzuki cross-coupling reaction. While reading background information on this reaction I learned that it won the Nobel Prize for Chemistry in 2010. Needless to say it is a very important reaction and a very key step in my overall synthesis. For the past two weeks I've had some trouble getting the reaction to work, as it is pretty tricky to set up. After trying the reaction 3 times and not being able to figure out why it wasn't working it was quite discouraging. My mentor Emily had to be in her other lab to complete further studies on her work in preparation for her dissertation committee meeting for graduate school, so I didn't have her around to ask direct questions and had to seek help elsewhere. Although, we did communicate often via phone and email and I'm thankful that she tried to help me as best as she could under her circumstances. That meant a lot. I consulted others in the lab for help, including Ramesh who has done this reaction before. I learned a lot and gained new understanding on this reaction and ways to ensure that the reaction works to completion. On the 5th try I finally reached product conversion! It wasn't much, but it gave me the motivation I needed to carry forward and improve my product yield. On the next try I acheived a better product yield and this was extremely exciting for me. I am now at the final step of my synthesis which looks even trickier than the Suzuki reaction. However, I am ready to take on the task and learn from this experience. After this step I will be able to radiolabel my compound and it will be ready for autoradiography analysis on rat brain samples. Hopefully all will go well. Don't you just love science?

-William Taylor