Inducible immortality in hTERT-human mesenchymal stem cells.

Human mesenchymal stem cells (hMSCs) are attractive candidates for tissue engineering and cell-based therapy because of their multipotentiality and availability in adult donors. However, in vitro expansion and differentiation of these cells is limited by replicative senescence. The proliferative capacity of hMSCs can be enhanced by ectopic expression of telomerase, allowing for long-term culture. However, hMSCs with constitutive telomerase expression demonstrate unregulated growth and even tumor formation. To address this problem, we used an inducible Tet-On gene expression system to create hMSCs in which ectopic telomerase expression can be induced selectively by the addition of doxycycline (i-hTERT hMSCs). i-hTERT hMSCs have inducible hTERT expression and telomerase activity, and are able to proliferate significantly longer than wild type hMSCs when hTERT expression is induced. They stop proliferating when hTERT expression is turned off and can be rescued when expression is re-induced. They retain multipotentiality in vitro even at an advanced age. We also used a selective inhibitor of telomere elongation to show that the mechanism driving immortalization of hMSCs by hTERT is dependent upon maintenance of telomere length. Thanks to their extended lifespan, preserved multipotentiality and controlled growth, i-hTERT hMSCs may prove to be a useful tool for the development and testing of novel stem cell therapies.

Does limb-salvage surgery offer patients better quality of life and functional capacity than amputation?

INTRODUCTION: Patients with aggressive lower extremity musculoskeletal tumors may be candidates for either above-knee amputation or limb-salvage surgery. However, the subjective and objective benefits of limb-salvage surgery compared with amputation are not fully clear. QUESTIONS/PURPOSES: We therefore compared functional status and quality of life for patients treated with above-knee amputation versus limb-salvage surgery. METHODS: We reviewed 20 of 51 patients aged 15 years and older treated with above-knee amputation or limb-salvage surgery for aggressive musculoskeletal tumors around the knee between 1994 and 2004 as a retrospective cohort study. At last followup we obtained the Physiological Cost Index, the Reintegration to Normal Living Index, SF-36, and the Toronto Extremity Salvage Score questionnaires. The minimum followup was 12 months (median, 56 months; range, 12-108 months). RESULTS: Compared with patients having above-knee amputation, patients undergoing limb-salvage surgery had superior Physiological Cost Index scores and Reintegration to Normal Living Index. The Toronto Extremity Salvage scores and SF-36 scores were similar in the two groups. CONCLUSION: These data suggest that limb-salvage surgery offers better gait efficiency and return to normal living compared with above-knee amputation, but does not improve the patient's perception of quality of life.

Relaxation effects of ferucarbotran-labeled mesenchymal stem cells at 1.5T and 3T: discrimination of viable from lysed cells.

Human mesenchymal stem cells (hMSCs) were labeled with Ferucarbotran by simple incubation and cultured for up to 14 d. Iron content was determined by spectrometry and the intracellular localization of the contrast agent uptake was studied by electron and confocal microscopy. At various time points after labeling, ranging from 1 to 14 d, samples with viable or lysed labeled hMSCs, as well as nonlabeled controls, underwent MRI. Spin-echo (SE) and gradient-echo (GE) sequences with multiple TRs and TEs were used at 1.5T and 3T on a clinical scanner. Spectrometry showed an initial iron oxide uptake of 7.08 pg per cell. Microscopy studies revealed lysosomal compartmentalization. Contrast agent effects of hMSCs were persistent for up to 14 d after labeling. A marked difference in the T(2) effect of compartmentalized iron oxides compared to free iron oxides was found on T(2)-weighted sequences, but not on T(2)*-weighted sequences. The observed differences may be explained by the loss of compartmentalization of iron oxide particles, the uniformity of distribution, and the subsequent increase in dephasing of protons on SE images. These results show that viable cells with compartmentalized iron oxides may-in principle-be distinguished from lysed cells or released iron oxides.

The functional anaesthetic discogram: description of a novel diagnostic technique and report of 3 cases.

BACKGROUND: The diagnostic evaluation of patients with presumed discogenic low back pain is controversial; recent studies have brought the specificity of the traditional technique, provocative lumbar discography, into question. One of the explanations for the relative lack of predictability in treatment outcomes for patients with discogenic low back pain may be a corresponding lack of certainty in the diagnosis. PURPOSE: A new diagnostic technique is described for the evaluation of patients with presumptive discogenic low back pain; the cases of 3 patients in whom the technique was used are presented. STUDY DESIGN/SETTING: Case report; university practice. METHODS: A technique is described in which an anaesthetic catheter is placed into putative symptomatic lumbar discs, the patient elicits his or her typical pain via a position or activity, and anaesthetic or placebo is delivered to the disc. The effect of the injected substance on the patient's pain is then noted. RESULTS: In one patient, the new test was confirmatory of the results of the provocative discogram; in two patients, the test results were divergent. CONCLUSIONS: These case studies and technical description are presented as a first step in examining this method of preoperative assessment. Further study of the technique will allow us to make more definitive recommendations with regards to its validity and utility. LEVEL OF EVIDENCE: Level 4 - Case Series.

Clostridium cadaveris septic arthritis after total hip arthroplasty in a metastatic breast cancer patient.

We report the first known case of septic arthritis in the setting of total hip arthroplasty caused by Clostridium cadaveris, a gas-forming anaerobic enteric organism usually considered a non-pathogen. This case occurred in a patient treated with total hip arthroplasty for metastatic breast cancer involving the acetabulum. The patient was managed successfully with debridement, prosthetic retention, and chronic antibiotic suppression. We propose this mode of care as a successful alternative for some patients with prosthetic joint infection and prohibitive comorbid conditions.

Surgical treatment for unstable low-grade isthmic spondylolisthesis in adults: a prospective controlled study of posterior instrumented fusion compared with combined anterior-posterior fusion.

BACKGROUND CONTEXT: The surgical treatment for low-grade isthmic spondylolisthesis in adults with intractable lumbar pain is usually spinal fusion. It has been postulated that anterior column reconstruction may be relatively advantageous in those patients with unstable slips. PURPOSE: To compare the early and medium term treatment efficacy of two common fusion techniques in isthmic spondylolisthesis. STUDY DESIGN/SETTING: Prospective controlled trial comparing single-level posterior-lateral instrumented fusion with combined anterior and posterior-lateral instrumented fusion in sequential matched cohorts of patients with radiographically unstable isthmic spondylolisthesis. OUTCOME MEASURES: Primary outcome measure of success was an Oswestry Disability Index (ODI)