New weapons against cancer?
July 15, 2010
At the UCLA Jonsson Comprehensive Cancer Center, a team of researchers is working on what can be the future in the battle against cancer. Radioactive reporter genes are embedded in lymphocytes, which have been genetically modified to recognize antigens on the surface of melanoma cells. The researchers were able to pack together the cancer specific T-cell receptor and the radioactively labeled reporter genes in a single vector and inject it into the intact immune systems of mice. By using PET imaging, the lymphocytes can be tracked.
By imaging the genetically engineered T cells as they seek out and attack the cancer, the processes of the immune system unfold. In the case of mice, within two to three days after being injected into the bloodstreams of the mice, the cells had found and begun to fight the melanoma. This could take much longer in humans, though.
Monitoring the immune response by PET imaging, could show whether the treatment is working or not, and why not. It also could show how the lymphocytes might be engineered to better fight the tumors.
It is expected that clinical trials in humans could start in one or two years.
For more details, please refer to the article published July 12, Proc Natl Acad Sci U S A, Kinetic phases of distribution and tumor targeting by T cell receptor engineered lymphocytes inducing robust antitumor responses. by Koya RC, Mok S, Comin-Anduix B, Chodon T, Radu CG, Nishimura MI, Witte ON, Ribas A.
Spectroscopy to diagnose back pain
June 18, 2010
Back pain is very common among the adult (and young) population. However, it is not always easy to diagnose the source of the pain. Currently, patients with lower back pain must undergo an invasive procedure known as provocative discography to help determine where the pain comes from. A die is injected into the disk via a needle until the patient reaches his or her pain threshold. Based on the level of pain expressed by the patient, the physician forms the diagnosis.
Nocimed (a Californian-based company) is currently testing Nociscan, a software that combines an MR spectroscopy sequence and postprocessing to identify chemical biomarkers of painful disks (degenerative disk disease MR – DDD MR).
There are two metabolites associated with painful disks: lactate and proteoglycan:
- Lactic acids build up in painful disks (the same phenomenon that makes muscle hurt).
- Proteoglycan holds water in the disks. A normal disk has a high content of water and proteoglycan. However, disk degeneration involves dehydration and proteoglycan breaks down. This also prevents nerve in-growth, creating a permissive environment for innervation of nociceptors [pain reporting nerves] that has been observed in the inner nuclei of degenerative painful disks (not found in healthy disks). In general, nocireceptive nerves and acidity means pain.
This technology is not yet commercially available. A two-year study has shown very good results and no false positives, but further investigation is still necessary.
Nevertheless, this new technology represents a step forward to diagnose lower back pain in a more efficient, non-invasive manner.
For more information, refer to:
- Keshari KR, Lotz JC, Link TM, et al. Lactic acid and proteoglycans as metabolic markers for discogenic back pain. Spine. 2008;33(3):312-317. PMID: 18303465
- Carragee EJ, Don AS, Hurwitz EL, et al. 2009 ISSLS Prize Winner: Does discography cause accelerated progression of degeneration changes in the lumbar disc: a ten-year matched cohort study. Spine. 2009;34(21):2338-2345. PMID: 19755936
- O’Neill C, Kurgansky M, Kaiser J, Lau W. Accuracy of MRI for diagnosis of discogenic pain. Pain Physician. 2008;11(3):311-326. PMID: 18523502
- Serena S et al. Modified Magnetic Resonance Spectroscopy Diagnosis of Painful and Non-Painful Lumbar Intervertebral Discs :Abstract
Patients, scanning and proper breathing…
June 16, 2010
Having your patients hold their breath properly during a MR or CT scan is always a challenge, especially when your patients are infants. Mueller et al. have come up with a simple volume-monitored (VM) method for performing reproducible, motion-free full inspiratory and end expiratory chest CT examinations in children. They tested the method on
fifty-two children with cystic fibrosis (mean age 8.8 ± 2.2 years). They underwent pulmonary function tests and inspiratory and expiratory VM-CT scans (1.25-mm slices, 80–120 kVp, 16–40 mAs) according to an IRB-approved protocol. The VM-CT technique utilizes instruction from a respiratory therapist, a portable spirometer and real-time documentation of lung volume on a computer. CT image quality was evaluated for achievement of targeted lung-volume levels and for respiratory motion. Overall, 94% of scans were performed at optimal volumes without respiratory motion. This method is applicable to children older than 4 years-old.
A drawback of the method, though, is the fact that the respiratory therapist has to stay in the room while the scan is being performed, with all the risks of radiation.
For more information you can read the whole article, published online in Pediatric Radiology (May 28, 2010): Volume-monitored chest CT: a simplified method for obtaining motion-free images near full inspiratory and end expiratory lung volumes
