Space Applications of Mass Spectrometry

Mass spectrometers have been involved in essentially all aspects of space exploration. This chapter outlines some of these many uses. Mass spectrometers have not only helped to expand our knowledge and understanding of the world and solar system around us, they have helped to put man safely in space and expand our frontier. Mass spectrometry continues to prove to be a very reliable, robust, and flexible analytical instrument, ensuring that its use will continue to help aid our investigation of the universe and this small planet that we call home

The magic bullet: Creating Indium-111 bombesin targeting vectors for use in diagnostic imaging of prostate and breast cancer [abstract]

Abstract only availableBackground: According to the American Cancer Society, over 68,000 men and women will die from prostate and breast cancer in this year alone. Prostate, breast and other cancers have been shown to express the BB2 receptor. For the past decade the Hoffman laboratory has been synthesizing radiopharmaceutical conjugates based on the Bombesin (BBN) peptide (Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2) that target the BB2 receptor for diagnosis and treatment of cancer. The radioconjugates are composed of a bombesin targeting vector, linking group, chelation moiety and a radioactive metal. One focus of our group is to investigate the efficacy of new Bombesin Targeting Vectors (BTV) which are derivatives of the BBN peptide. In the sixth position of the BTV is a D-phenylalanine amino acid. Our hypothesis is that the D-phenylalanine is responsible for significantly reducing kidney retention. Reduction of kidney retention is crucial for clinical radiotherapeutic applications because the kidney is often the dose limiting organ. In order to understand the structure function relationship of the D-phenylalanine in the BTV targeting vectors, we synthesized and evaluated the BTV peptide with the L-phenylalanine in the sixth position to determine what effect the stereochemistry has upon the in vitro receptor binding and in vivo pharmacokinetic properties of the peptide. Methods: The peptides were synthesized using solid phase peptide synthesis, purified using RP-HPLC, and characterized using electrospray mass spectrometry. Radiolabeling of the peptides was performed using 111InCl3. In vitro cell binding assays and internalization and efflux studies were performed using the PC-3 human cancer cell line. In vivo pharmacokinetic studies were performed using CF-1 mice. Micro-SPECT (single photon emission computed tomography) imaging studies were performed in PC-3 SCID mice. Results: In vivo pharmacokinetic studies at 15 min post-injection gave 39.85 ± 5.07 %ID/g in the BB2 receptor expressing mouse pancreas for the L-Phe-BTV radioconjugate compared to 10.30 ± 0.34 for the D-Phe-BTV. Surprisingly, the kidney clearance for both radioconjugates was statistically identical. Conclusion: Incorporation of the L-Phe instead of the D-Phe into the sixth position of the BTV had no statistically significant effect upon the renal clearance of the radioconjugate. However, the change in stereochemistry from the L to the D-form had significant effects upon the in vivo uptake and retention of the radioconjugate. Further investigations will be conducted to understand the mechanism responsible for the difference in uptake and retention of the two Bombesin radioconjugates

Using Indium-111 labeled radiopharmaceuticals to target the BB2 receptor on human prostate cancer cells [abstract]

Abstract only availableThe BB2 receptor, belonging to the Bombesin receptor family, has been shown to be highly over expressed in a variety of cancer cell lines, including human prostate cancer. Our laboratory have been involved, for over a decade, in synthesizing Bombesin analogues that target the BB2 receptor for the purpose of developing radiopharmaceuticals for diagnostic and/or therapeutic treatment of cancer. Radiopharmaceuticals based on Bombesin are typically composed of a chelator, isotope, linking group and targeting vector [See Bifunctional Conjugate Design [figure below]. Previous studies by our group and others have shown that variations in linking groups affect the retention time of the bifunctional conjugate in prostate cancer (PC-3) cells. Higher retention time allows for more efficacious therapeutic benefits and enhanced diagnostic imaging capabilities. In this study, we seek to determine the pharmacokinetic benefits achieved in altering the linking group using aliphatic and aromatic linking groups. In-vitro analysis of the radiopharmaceuticals studied found that the Bombesin derivative with the aliphatic linking group demonstrated a slightly higher affinity for the BB2 receptor compared to the Bombesin analogs containing aromatic linking groups. In vivo pharmacokinetic and imaging studies were performed using pre-clinical models of prostate cancer. The tumor uptake of the Bombesin derivatives with the aromatic linking groups were found to be significantly higher compared to that of the Bombesin derivative with the aliphatic linking group. In contrast, the aromatic Bombesin analogs also exhibited higher amounts of undesirable accumulation in the kidneys and other non-target tissues. In conclusion, we found that the aliphatic compounds were more appropriate for diagnostic imaging of prostate cancer due to the reduced non-target retention. The Bombesin analogs with aromatic linking groups showed potential for use as therapeutic agents for prostate cancer treatment.National Institutes of Health Molecular Imaging Progra

Targeting the BB2 receptor on human prostate cancer cells using Indium-111 labeled radiopharmaceutical [abstract]

Abstract only availableFaculty Mentor: Dr. Timothy Hoffman, Internal MedicineThe BB2 receptor, belonging to the Bombesin receptor family, has been shown to be highly over expressed in a variety of cancer cell lines, including human prostate cancer. Over expression of the BB2 receptor offers an appealing target for the design of targeted radiopharmaceuticals.  The Hoffman laboratory and others have been involved, for over a decade, in synthesizing Bombesin analogues that target the BB2 receptor for the purpose of developing a viable radiopharmaceutical for diagnostic or therapeutic treatment of cancer. Radiopharmaceuticals based on Bombesin analogues are typically composed of a targeting vector, radioisotope, chelator and linking group [See Bifunctional Conjugate Design figure below]. Previous studies have shown that variations in linking groups may affect the retention time of the bifunctional conjugate in prostate cancer (PC-3) cells.  Higher retention time allows for more efficacious therapeutic benefits and enhanced diagnostic imaging capabilities.  In the work presented, we designed and synthesized a 111In-Bombesin analogue with a phenyl linker group in order to determine if the phenyl linker group would provide higher retention times in prostate cancer.  In-vitro analysis of the radiopharmaceutical was performed using PC-3 cells to determine the affinity of the new compound for the BB2 receptor to be 1.09 nM. In-vivo studies of the radiopharmaceutical were also conducted by injection of the radiopharmaceutical into CF-1 (“normal”) mice, as well as SCID (Severe Combined Immunodeficient) mice bearing 2-3 week old PC-3 tumors. Experimental results on SCID mice revealed uptakes of 6.36, 3.34, 2.42 and 1.69 % Injected Dose of radiopharmaceutical per gram of tumor tissue at 0.25, 1, 4 and 24 hours, respectively. Imaging using Micro-SPECT (Single-Photon Emission Computed Tomography) was performed to track the dispersion of the radiopharmaceutical throughout the mouse model and confirmed the targeted uptake of the radiopharmaceutical

Characterization and Structure of a Zn2+ and [2Fe-2S]-containing Copper Chaperone from Archaeoglobus Fulgidus

Bacterial CopZ proteins deliver copper to P1B-type Cu+-ATPases that are homologous to the human Wilson and Menkes disease proteins. The genome of the hyperthermophile Archaeoglobus fulgidus encodes a putative CopZ copper chaperone that contains an unusual cysteine rich N-terminal domain of 130 amino acids in addition to a C-terminal copper-binding domain with a conserved CXXC motif. The N-terminal domain (CopZ-NT) is homologous to proteins found only in extremophiles and is the only such protein that is fused to a copper chaperone. Surprisingly, optical, electron paramagnetic resonance, and X-ray absorption spectroscopic data indicate the presence of a [2Fe-2S] cluster in CopZ-NT. The intact CopZ protein binds two copper ions, one in each domain. The 1.8 Å resolution crystal structure of CopZ-NT reveals that the [2Fe-2S] cluster is housed within a novel fold and that the protein also binds a zinc ion at a four cysteine site. CopZ can deliver Cu+ to the A. fulgidus CopA N-terminal metal binding domain and is capable of reducing Cu2+ to Cu+. This unique fusion of a redox-active domain with a CXXC-containing copper chaperone domain is relevant to the evolution of copper homeostatic mechanisms and suggests new models for copper trafficking

Statistical Modeling of Extracellular Vesicle Cargo to Predict Clinical Trial Outcomes For Hypoplastic Left Heart Syndrome

Cardiac-derived c-kit+ progenitor cells (CPCs) are under investigation in the CHILD phase I clinical trial (NCT03406884) for the treatment of hypoplastic left heart syndrome (HLHS). The therapeutic efficacy of CPCs can be attributed to the release of extracellular vesicles (EVs). to understand sources of cell therapy variability we took a machine learning approach: combining bulk CPC-derived EV (CPC-EV) RNA sequencing and cardiac-relevan

Low-Intensity Blast Induces Acute Glutamatergic Hyperexcitability in Mouse Hippocampus Leading to Long-Term Learning Deficits and Altered Expression of Proteins Involved in Synaptic Plasticity and Serine Protease Inhibitors

Neurocognitive consequences of blast-induced traumatic brain injury (bTBI) pose significant concerns for military service members and veterans with the majority of invisible injury. However, the underlying mechanism of such mild bTBI by low-intensity blast (LIB) exposure for long-term cognitive and mental deficits remains elusive. Our previous studies have shown that mice exposed to LIB result in nanoscale ultrastructural abnormalities in the absence of gross or apparent cellular damage in the brain. Here we tested the hypothesis that glutamatergic hyperexcitability may contribute to long-term learning deficits. Using brain slice electrophysiological recordings, we found an increase in averaged frequencies with a burst pattern of miniature excitatory postsynaptic currents (mEPSCs) in hippocampal CA3 neurons in LIB-exposed mice at 1- and 7-days post injury, which was blocked by a specific NMDA receptor antagonist AP5. In addition, cognitive function assessed at 3-months post LIB exposure by automated home-cage monitoring showed deficits in dynamic patterns of discrimination learning and cognitive flexibility in LIB-exposed mice. Collected hippocampal tissue was further processed for quantitative global-proteomic analysis. Advanced data-independent acquisition for quantitative tandem mass spectrometry analysis identified altered expression of proteins involved in synaptic plasticity and serine protease inhibitors in LIB-exposed mice. Some were correlated with the ability of discrimination learning and cognitive flexibility. These findings show that acute glutamatergic hyperexcitability in the hippocampus induced by LIB may contribute to long-term cognitive dysfunction and protein alterations. Studies using this military-relevant mouse model of mild bTBI provide valuable insights into developing a potential therapeutic strategy to ameliorate hyperexcitability-modulated LIB injuries

Multicenter evaluation of parametric response mapping as an indicator of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156134/2/ajt15814_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156134/1/ajt15814.pd