Characterization of an in vitro intervertebral disc organ culture system

Intervertebral disc organ culture has the capacity to control mechanical and chemical boundary conditions while keeping the tissue largely intact, and allowing interventions that would be impossible or unethical on animal studies. Recent studies on ex vivo organ culture has mostly involved small animals, or been limited to development and validation studies. In this study, bovine caudal discs were used. The large animal model design ensures that sufficient tissue is available for measurement of multiple dependent variables on the same disc, and a similar aspect ratio, diffusion distance, composition and rate of proteoglycan synthesis to human lumbar discs. The first goal of this study was to refine a set of dependent variables capable of characterizing the response of the intervertebral disc to culturing and to develop a technique to measure cell viability in all three regions of the disc. The second goal was to use these variables to compare static and diurnal loading as a method of maintaining intervertebral disc structure, composition, and cell metabolism similar to the in vivo state. Static (0.2 MPa) and diurnal loading (0.1 and 0.3 MPa alternating at 12 h intervals) were applied and intervertebral discs were examined after 4 or 8 days with dependent variables including changes in geometry (disc height and diameter), composition (tissue water content, tissue proteoglycan content and proteoglycan content lost to the culture media), cell viability and metabolism (proteoglycan synthesis). Results indicate that there was a decrease in disc height and water content after culture regardless of culture duration or loading condition. Cell viability significantly decreased with culture duration in the inner annulus and nucleus; however, a significant reduction in cell viability for the diurnal versus static loading condition was only observed after 8 days in the nucleus region. No significant differences were seen in viability of the outer annulus region with time, or in any loading groups. We conclude that our system is capable of keeping bovine caudal discs alive for at least 8 days without significant changes in GAG content, or cell metabolism, and that static loading was slightly better able to maintain cell viability than diurnal loading. This system offers promise for the future studies on large intervertebral discs requiring measurements of multiple mechanical and biological dependent variables on the same tissue.     

Does preoperative symptom classification impact prognosis in patients with clinically localized upper-tract urothelial carcinoma managed by radical nephroureterectomy?

ObjectivesTo evaluate if preoperative symptom classification could refine prediction of outcomes for patients with clinically localized upper-tract urothelial carcinoma (UTUC) managed by radical nephroureterectomy (RNU).MethodsData on 654 patients with localized UTUC who underwent RNU were reviewed. Preoperative symptoms were classified as incidental (S1), local (S2), and systemic (S3). Clinical and pathologic data were compared between the cohorts. Kaplan-Meier analyses and Cox proportional hazard modeling were used to determine recurrence-free and cancer-specific survival amongst the symptom cohorts.ResultsSymptom classification was S1 in 213 (33%) patients, S2 in 402 (61%), and S3 in 39 (6%). S3 symptoms were associated with advanced pathology, including higher stage, grade, and lymph node (LN) positivity. Five and 10-year recurrence-free and cancer-specific survival estimates were similar for patients with S1 and S2 symptoms (P = 0.75 and 0.58, respectively), but was worse for patients with S3 symptoms (P < 0.001 for both). On multivariate analysis adjusting for final pathologic stage, grade, and LN status, S3 symptoms were not an independent predictor of recurrence (HR 1.44, P = 0.19) or death due to disease (HR 1.66, P = 0.07). Addition of symptom classification, however, increased the accuracy of a model consisting of stage, grade, and LNs for prediction of recurrence-free and cancer-specific survival by 1.4% and 1.3%, respectively (P < 0.001 for both).ConclusionsLocal symptoms do not confer worse prognosis compared with patients with incidentally detected UTUC. However, systemic symptoms are associated with worse outcomes despite apparently effective RNU. Patients with systemic symptoms may harbor micrometastatic disease and could potentially benefit from a more rigorous metastatic evaluation or perioperative chemotherapy regimens.     

A graded forceps crush spinal cord injury model in mice

Given the rising availability and use of genetically modified animals in basic science research, it has become increasingly important to develop clinically relevant models for spinal cord injury (SCI) for use in mice. We developed a graded forceps crush model of SCI in mice that uses three different forceps with spacers of 0.25, 0.4, and 0.55 mm, to produce severe, moderate, and mild injuries, respectively. Briefly, each mouse was subjected to laminectomy of T5-T7, 15-second spinal cord crush using one of those forceps, behavioral assessments, and post-mortem neuroanatomical analyses. There were significant differences among the three injury severity groups on behavioral measures (Basso Mouse Score, footprint, and ladder analyses), demonstrating an increase in neurological deficits for groups with greater injury severity. Quantitative analysis of the lesion demonstrated that as injury severity increased, lesion size and GFAP negative area increased, and spared tissue, spinal cord cross-sectional area, spared grey matter and spared white matter decreased. These measures strongly correlated with the behavioral outcomes. Similar to other studies of SCI in mice, we report a dense laminin and fibronectin positive extracellular matrix in the lesion sites of injured mice, but unlike those previous studies, we also report the presence of numerous p75 positive Schwann cells in and around the lesion epicenter. These results provide evidence that the graded forceps crush model is an attractive alternative for the study of SCI and related therapeutic interventions. Because of its demonstrated consistency, ease of use, low cost, and clinical relevance, this graded forceps crush is an attractive alternative to the other mouse models of SCI currently available.     

Questionnaire survey of the views of the delegates at the European Cervical Spine Research Society meeting on the administration of methylprednisolone for acute traumatic spinal cord injury

STUDY DESIGN: A questionnaire survey. OBJECTIVES: To collate and analyze the views of the delegates who attended the European Cervical Spine Research Society (CSRS) meeting on the use of methylprednisolone for acute traumatic spinal cord injury. SUMMARY OF BACKGROUND DATA: The NASCIS II and III studies reported improved neurologic recovery in patients who were treated with methylprednisolone within 8 hours of their acute traumatic spinal cord injury. A number of reported commentaries have criticized these trials. A recent audit in the authors' regional spinal injuries unit in the United Kingdom found that a large percentage of patients were not receiving methylprednisolone. The authors decided to collate the views of the delegates at the CSRS regarding the use of steroids for acute traumatic spinal cord injury. METHODOLOGY: A questionnaire was created that took into account the positive reported findings as well as the criticisms of the NASCIS studies. Delegates who attended the European CSRS meeting completed this questionnaire. RESULTS: Seventy-five percent of the delegates answered that they used or recommended methylprednisolone in the treatment of acute traumatic spinal cord injury. Nevertheless, the delegates had an average of 1.5 reservations about administering methylprednisolone. The most common reservation was that they did not think the improvement conferred to the patients by administering methylprednisolone had been clinically or functionally proven. There were reservations about the validity of the statistical analysis used in the NASCIS studies and by the omission of a placebo group in NASCIS III. The majority of the delegates thought it was not medicolegally negligent to withhold the administration of methylprednisolone in the treatment of acute traumatic spinal cord injury. CONCLUSION: The use of methylprednisolone in the treatment of acute traumatic spinal cord injury is still controversial. It would appear from a recent prospective audit at the authors' spinal injuries unit that a large percentage of patients in the United Kingdom are not receiving methylprednisolone. Because so much doubt exists, the NASCIS studies should be repeated.     

Virtual hepatic resection using three-dimensional reconstruction of helical computed tomography angioportograms

OBJECTIVE: To establish the accuracy of virtual hepatic resection using three-dimensional (3D) models constructed from computed tomography angioportography (CTAP) images in determining the liver volume (LV) resected during resectional liver surgery. SUMMARY BACKGROUND DATA: The ability to measure LV before surgery could be useful in determining the extent and nature of hepatic resection. Accurate assessment of LV and an estimate of liver function may also allow prediction of postoperative liver failure in patients undergoing resection, assist in volume-enhancing embolization procedures, help with the planning of staged hepatic resection for bilobar disease, and aid in selection of living-related liver donors. METHODS: A retrospective study was conducted involving 27 patients scheduled for liver resection. Using mapping technology, 3D models were constructed from helical CTAP images. From these 3D models, tumor volume, total LV, and functional LV were calculated and were compared with body weight. The 3D liver models were subjected to a virtual hepatectomy along established anatomical planes, and the resected LV was calculated. The resected volume predicted by radiologists (unaware of the actual weight) was compared with the specimen weight measured after actual surgical resection. RESULTS: A significant correlation was found between body weight and functional LV but not total LV. The computer prediction of resected LV after virtual hepatectomy of 3D models compared well with resected liver weight. CONCLUSION: Virtual hepatectomy of 3D CTAP reconstructed images provides an accurate prediction of liver mass removed during subsequent hepatic resection. The authors intend to combine this technology with an assessment of liver function to attempt to predict patients at risk for liver failure after hepatic resection.     

Sleep disorders: Serious threats among kidney transplant recipients

In patients with chronic kidney disease (CKD) and kidney transplant recipients who continue to have some degree of CKD, the prevalence of sleep-related disorders is very high. Common sleep disorders in both groups include insomnia, sleep-disordered breathing (SDB), restless legs syndrome (RLS), excessive daytime sleepiness (EDS), and others. Depending on the kidney graft function, some patients see sleep disorders resolve after kidney transplantation, while others continue to have persistent sleep disorders or develop new ones. Kidney transplant recipients (KTRs) are unique patients due to the presence of a single kidney, the use of immunosuppressive medications, and other comorbidities including obesity, a high risk of cardiovascular disease, malignancy, and the anxiety of losing their allograft. All of these factors contribute to the risk for sleep disorders. CKD and sleep disorders have a bidirectional relationship; that is, CKD may increase the risk of sleep disorders and sleep disorders may increase the risk of CKD. Obstructive sleep apnea (OSA) is the most common form of SDB and is known to alter renal hemodynamics. OSA leads to hypoxemia and sleeps fragmentation, which activates the sympathetic nervous system. This activates the renin-angiotensin-aldosterone system and ultimately alters cardiovascular hemodynamics. Sleep disorders may have deleterious effects on the kidney allograft and proper screening and management are important for both graft and patient survival.