Backpack Forces on the Spine.

OBJECT: Backpacks are standard load carriers for people of all ages, especially school children and the military. Previous studies have described the impact of the forces exerted by backpacks on load distribution, back pain, and gait. The objective of this study was to use finite element analysis (FEA) to assess the effects of incremental weights in a backpack on the spine. METHODS: To assess the forces experienced by the spine under the incremental addition of weight to a backpack, we performed a finite element simulation using commercially available 'BodyParts3D/Anatomography' data, which were imported into FEA software. We studied two different scenarios: 1) a regular backpack with incrementally placed weights using both shoulder straps with the spine in a neutral position, and 2) a regular backpack with incrementally placed weights using both shoulder straps with the spine tilted forward 20 degrees. The spine model was physiologically accurate. RESULTS: For all of the added weights examined (1-100 pounds; 0.45-45.36 kg), the force experienced by the neutral spine was 7.2-fold the added weight. For the 20 degrees-forward posture, this value rose to 11.6-fold. CONCLUSIONS: These findings should help to clarify the forces experienced by the spine due to objects in a backpack. For example, this should help spinal surgeons to better understand the tremendous importance of sagittal plane alignment in planning their surgical reconstructions.

Effects of a manual medicine treatment procedures on nitric oxide release in 23 healthy adults.

OBJECTIVE: The objective of this study was to measure if a manual treatment would alter the levels of exhaled nitric oxide levels in healthy adults. METHODS: A study was performed using 23 healthy adults (age, 18-30 years). Nitric oxide (NO) was measured amperometrically before and after a manual treatment. The treatment used was a cranial-thoracic trapezius stretch. RESULTS: In healthy adults, manual manipulation was associated with changes in NO levels in exhaled breath. The level of NO increased from 13.3 +/- 2.09 (SD) to 15.0 +/- 2.95 (SD) ppb (P = .001, based upon the paired t tests of the subjects). The median level of NO before manual manipulation was 13.0 ppb (ranging from 8 to 17ppb); after manual manipulation, it was 16.0 ppb (ranging from 6 to 18 ppb). CONCLUSION: The cranial-thoracic trapezius stretch was associated with an increase in exhaled NO, compared to baseline levels for the subjects in this study.

Intravesical delivery of rapamycin suppresses tumorigenesis in a mouse model of progressive bladder cancer.

Early-stage bladder cancer occurs as two distinct forms: namely, low-grade superficial disease and high-grade carcinoma in situ (CIS), which is the major precursor of muscle-invasive bladder cancer. Although the low-grade form is readily treatable, few, if any, effective treatments are currently available for preventing progression of nonmuscle-invasive CIS to invasive bladder cancer. Based on our previous findings that the mammalian target of Rapamycin (mTOR) signaling pathway is activated in muscle-invasive bladder cancer, but not superficial disease, we reasoned that suppression of this pathway might block cancer progression. To test this idea, we performed in vivo preclinical studies using a genetically engineered mouse model that we now show recapitulates progression from nonmuscle-invasive CIS to muscle-invasive bladder tumors. We find that delivery of Rapamycin, an mTOR inhibitor, subsequent to the occurrence of CIS effectively prevents progression to invasive bladder cancer. Furthermore, we show that intravesical delivery of Rapamycin directly into the bladder lumen is highly effective for suppressing bladder tumorigenesis. Thus, our findings show the potential therapeutic benefit of inhibiting mTOR signaling for treatment of patients at high risk of developing invasive bladder cancer. More broadly, our findings support a more widespread use of intravesical delivery of therapeutic agents for treatment of high-risk bladder cancer patients, and provide a mouse model for effective preclinical testing of potential novel agents.