Dancers Show More Accurate Trunk-Pelvic Joint Angle Reproduction While Wearing a Jacket Augmented With Elastic Bands

Purpose: The Backalast® compression jacket is intended to improve posture and proprioception of the trunk and shoulder girdle for dancers and dance students during dance training by way of elastic bands in the rear of the garment (which include bands enclosing the inferior thorax). This study was intended to investigate whether there is evidence to support those objectives. Materials and Methods: Fifteen dance students participated (4 male, mean age 19.9 ± 1.4 years old). The dependent variables of trunk-pelvis angle and proximity of trunk axis to global vertical for each participant were measured using optical motion capture before and after the completion of a series of trunk movements. The Helen Hayes model, which we used to represent the trunk, includes the shoulder girdles as part of the trunk. We compared the effect of the type of garment (Backalast® or control compression shirt) worn upon the 2 dependent variables, within-subject with paired t-tests. The order of whether Backalast® or control compression shirt was worn first was alternated between participants. Results: The pre/posttest difference in trunk proprioception as represented by the construct of ability to reproduce trunk-pelvis angle wearing the Backalast® was 0.8° ± 0.8°, but for the control shirt, the difference was 1.8° ± 1.4°, P = .03. The difference between garments in vertical trunk alignment, measured after the series of trunk movements, was not significant. Conclusion: Our findings suggest that the Backalast® can help enhance trunk proprioception when compared to the control compression shirt, although it did not change the angle at which the participants' held their trunks while standing erect (proximity to global vertical).

Low Stiffness Dance Flooring Increases Peak Ankle Plantar Flexor Muscle Activation During a Ballet Jump

INTRODUCTION

Research in court sports shows that factors which aid in extrinsic shock absorption, that is, flooring and footwear, can help reduce lower extremity injuries. However, since students and performers of ballet or most styles of contemporary dance cannot depend upon footwear, the only extrinsic factor to help them with shock absorption is flooring.

METHODS

We investigated whether doing sauté on a low stiffness dance floor produced a difference in EMG output of the vastus lateralis, gastrocnemius, of soleus compared to a high stiffness floor. Average and average peak amplitude EMG output from 18 dance students or active dancers performing 8 repetitions of sauté on a low stiffness floor (Harlequin® Woodspring) was compared to a maple hardwood floor on concreted subflooring.

RESULTS

The data showed a significant increase in average peak EMG muscle amplitude during jumping on the low stiffness floor compared to a high stiffness floor for the soleus muscle (P = .033) and a trend for increase average peak output for the medial gastrocnemius (P = .088).

CONCLUSION

The difference in average peak amplitude of EMG output is explained through the difference in force absorption between floors. With the high stiffness floor, more force of the landing was returned to the dancers' legs, but the low stiffness floor absorbed some of the force of landing the jump, and therefore muscles needed to contribute more to maintain the same jump height. The force absorption characteristic of the low stiffness floor may decrease injury rates in dance through causing an adjustment in muscle velocity. Rapid eccentric muscle activity carries the greatest possibility of musculotendinous injury and is experienced in lower body muscles controlling all joints during impact absorption, which includes landing of jumps in dance. If a surface can decelerate the landing of a high velocity dance movement, it also decreases the musculotendinous demand for high velocity tension generation.

Intraparenchymal Schwannoma: A Rare Entity

A 60-year-old woman noted headaches, transient visual obscurations and pulsatile tinnitus. She had Frisén grade 4 papilloedema. Brain magnetic resonance imaging showed a large subfrontal cystic mass with ring enhancement. Tumour pathology was in-keeping with an intraparenchymal schwannoma. This uniquely rare tumour is discussed.

TAMI-39. AGE-DEPENDENT PHENOTYPIC CONVERSION FROM NEURONAL ACTIVITY TO NEURO-INFLAMMATION IN GLIOBLASTOMA PROGRESSION

The rise in population aging worldwide is causing an unparalleled increase in death from many cancers, including glioblastoma (GBM). Here, we have explored the impact of aging and rejuvenation on GBM tumorigenesis. Compared with neuro-inflammatory old GBM, young GBM displayed elevated neuronal/synaptic signaling via brain-derived neurotrophic factor (BDNF) and SLIT and NTRK like-family member 6 (SLITRK6), promoting favorable survival rates. These effects were attributed to the rise in nicotinamide adenine dinucleotide (NAD+) levels, as brain rejuvenation by parabiosis or administration of nicotinamide mononucleotide (NMN) in mice elicited a younger phenotype with activated neuronal/synaptic signaling and improved outcomes. Our data indicate that age-associated NAD+ loss contributes to the highly aggressive GBM by the shift from neuronal/synaptic activity to neuro-inflammation in the elderly brain. These findings have therapeutic and preventive implications in GBM and provide mechanistic insights into the exacerbation of GBM tumorigenesis by aging.

Intraventricular metastatic melanoma: A case report and review of the literature

Intraventricular melanoma is a very rare and highly malignant disease. Safe resection is the mainstay of treatment, but no standard guidelines exist for adjuvant therapy. Early histologic and molecular diagnosis is key for improved survival.

Cerebellar Arteriovenous Malformation Rupture Despite Apparent Angiographic Obliteration

BACKGROUND

Arteriovenous malformations (AVMs) can occur in all regions of the brain and spinal cord, with clinical consequences and risks varying by location. Delayed AVM rupture despite digital subtraction angiography-confirmed obliteration post-radiation is exceedingly rare.

CASE DESCRIPTION

To our knowledge, we present the first documented case of delayed hemorrhage associated with a cerebellar AVM 5 years after linear accelerator-based radiation in a man aged 31 years despite apparent angiographic obliteration.

CONCLUSIONS

Intracranial hemorrhage after radiosurgery in digital subtraction angiography-confirmed obliterated AVMs is rare, with limited understanding of risk factors, appropriate preventative management, and mechanisms of occurrence. This case serves to demonstrate the need for greater awareness of this rare complication, as well as the need for appropriate surveillance and management strategies.

Angiosarcoma of the Temporal Bone: Case Report and Review of the Literature

BACKGROUND

Angiosarcomas are rare malignant tumors of endothelial origin. Nearly one half of all angiosarcomas occur in the head and neck. Temporal bone angiosarcomas are extremely uncommon. We present a case of temporal bone angiosarcoma and a review of the relevant data.

CASE DESCRIPTION

We present the case of a 20-year-old man with a painful right postauricular mass after a closed head injury. Radiologic studies demonstrated a large right osteolytic and heterogeneously enhancing mass. The patient underwent right transpetrosal craniectomy for resection. Histologic studies confirmed high-grade sarcoma. Immunohistochemical staining demonstrated a uniformly positive ERG endothelial marker, CD31 staining with cytoplasmic and membranous patterns of immunopositivity, positive nuclear staining for FLI-1, positive cytoplasmic and membranous staining for CD99 and STAT6, and negative smooth muscle actin stains in the neoplastic cells. Ki-67 staining showed ∼94% positivity in the neoplastic cell nuclei. Postoperative follow-up imaging studies demonstrated evidence of metastatic right cervical lymphadenopathy.

CONCLUSIONS

Angiosarcoma of the temporal bone is extremely uncommon. In the present case report, we explored a relationship between trauma and angiosarcoma of the temporal bone. We reviewed the reported data regarding the pathogenesis, diagnosis, treatment, radiologic findings, and histologic characteristics of angiosarcoma of the temporal bone.

Effect of Reduced Stiffness Dance Flooring on Lower Extremity Joint Angular Trajectories During a Ballet Jump

We carried out a study to investigate how low stiffness flooring may help prevent overuse injuries of the lower extremity in dancers. It was hypothesized that performing a ballet jump (sauté) on a reduced stiffness dance floor would decrease maximum joint flexion angles and negative angular velocities at the hips, knees, or ankles compared to performing the same jump on a harder floor. The participants were 15 young adult female dancers (age range 18 to 28, mean = 20.89 ± 2.93 years) with at least 5 years of continuous ballet experience and without history of serious lower body injury, surgery, or recent pain. They performed sautés on a (low stiffness) Harlequin ® WoodSpring Floor and on a vinyl-covered hardwood on concrete floor. Maximum joint flexion angles and negative velocities at bilateral hips, knees, and ankles were measured with the "Ariel Performance Analysis System" (APAS). Paired one-tailed t-tests yielded significant decreases in maximum knee angle (average decrease = 3.4° ± 4.2°, p = 0.026) and angular negative velocity of the ankles (average decrease = 18.7°/sec ± 27.9°/sec, p = 0.009) with low stiffness flooring. If the knee angle is less acute, then the length of the external knee flexion moment arm will also be shorter and result in a smaller external knee flexion moment, given an equal landing force. Also, high velocities of eccentric muscle contraction, which are necessary to control negative angular velocity of the ankle joint, are associated with higher risk of musculotendinous injury. Hence, our findings indicate that reduced floor stiffness may indeed help decrease the likelihood of lower extremity injuries.

Effect of sprung (suspended) floor on lower extremity stiffness during a force-returning ballet jump

Our objective in this study was to compare stiffness of bilateral lower extremities (LEs) in ballet dancers performing sauté on a low-stiffness "sprung floor" to that during the same movement on a high-stiffness floor (wood on concrete). LE stiffness was calculated as the ratio of vertical ground reaction force (in kN) to compression of the lower limb (in meters). Seven female dancers were measured for five repetitions each at the point of maximum leg compression while performing sauté on both of the surfaces, such that 43 ms of data were represented for each trial. The stiffness of bilateral LEs at the point of maximum compression was higher by a mean difference score of 2.48 ± 2.20 kN/m on the low-stiffness floor compared to a high-stiffness floor. Paired t-test analysis of the difference scores yielded a one-tailed probability of 0.012. This effect was seen in six out of seven participants (one participant showed no difference between floor conditions). The finding of increased stiffness of the LEs in the sprung floor condition suggests that some of the force of landing the jump was absorbed by the surface, and therefore did not need to be absorbed by the participants' LEs themselves. This in turn implies that a sprung dance floor may help to prevent dance-related injuries.

The effect of sprung (suspended) floors on leg stiffness during grand jeté landings in ballet

This study compared stiffness of the landing leg in ballet dancers performing grand jeté on a sprung floor to leg stiffness during the same movement on a hard floor (wood on concrete). Leg stiffness was calculated as the ratio of vertical ground reaction force (in Newtons) to compression of the lower limb (in meters). Thirteen female dancers were measured for five repetitions each at the point of maximum leg compression while landing grand jeté on both of the surfaces, such that 20 milliseconds of data were represented for each trial. The stiffness of the landing leg at the point of maximum compression was decreased by a mean difference score of 6168.0 N/m ± 11,519.5 N/m on the hard floor compared to the sprung floor. Paired t-test yielded a one-tailed probability of p = 0.038. This effect was seen in 11 of the 13 participants. The finding of increased stiffness of the landing leg in the sprung floor condition suggests that some of the force of landing the leap was absorbed by the surface, and therefore did not need to be absorbed by the landing leg itself. This in turn implies that a sprung dance floor may help to prevent dance-related injuries.

Eddies in the stream: the prevalence of uncertain plans for retirement

OBJECTIVE

This study examined an assumption of retirement theory that typifies older workers as preretirees who are planfully engaged in paths toward retirement.

METHODS

Using survey responses among workers in the 1992 and 1994 waves of the Health and Retirement Study, we described the prevalence of nonsubstantive answers to questions about the expected form and timing of retirement (e.g., "don't know," "haven't thought about it"). We tested explanations for this uncertainty as an artifact of the survey process, but also as an outcome of the opportunity structure for retirement planning.

RESULTS

Survey procedure did generate some of these noncommittal responses. Depending on question type, approximately 10% to 40% of workers did not state when or how they would retire, and such responses were less prevalent across age and time. In addition, categorical uncertainty about form and timing was theoretically predictable in a framework that supposed that workers less subject to a socially attended life--at work or away--would be more undecided about the future.

DISCUSSION

Uncertainty is an authentic, meaningful stance toward retirement that theory and research design should not ignore. Just as actual transitions to retirement can be ambiguous or blurred, the expectation of retirement, as well, can be untidy.

A feasibility study of gene gun mediated immunotherapy for renal cell carcinoma

PURPOSE

Gene modified autologous tumor cell vaccines have demonstrated a protective and therapeutic effect in murine tumor model systems. The majority of trials to date have used viral methods of gene transfer for vaccine construction. An alternative approach to transfer genes into tumor cells is to use the gene gun, which is a physical method of gene transfection that produces high levels of gene expression without viral agents. We establish the feasibility of generating cytokine secreting autologous renal tumor cell vaccines for use in gene therapy for metastatic renal cell carcinoma.

MATERIALS AND METHODS

We obtained 1 cm3 tumor tissue from 12 patients undergoing resection of primary or metastatic renal cell carcinoma. The tumor was disaggregated and placed in culture. The phenotype of the primary renal cell lines was established by microscopy and immunohistochemistry. The 1x10(7) lethally irradiated tumor cells were transfected with plasmid deoxyribonucleic acid containing the human (h) granulocyte-macrophage colony-stimulating factor (GM-CSF) gene under control of a cytomegalovirus promoter using the gene gun. The hGM-CSF production was assayed by enzyme-linked immunosorbent assay in the cell culture media 24 hours after transfection.

RESULTS

Of 12 tumor samples 8 grew rapidly to produce a mean of 1.8x10(8) cells after 4 to 5 passages in culture, which was sufficient to produce between 24 and 32 vaccines. Immunocytochemistry confirmed that all cultures were almost exclusively renal tumor cells. Gene gun mediated transfection of lethally irradiated tumor cells resulted in high levels of hGM-CSF production (mean 330 ng./10(6) cells per 24 hours).

CONCLUSIONS

We have demonstrated the feasibility of producing cytokine secreting tumor cell vaccines from primary and metastatic human renal tumors, and plan to use this approach in phase I clinical trials of gene therapy for metastatic renal cell carcinoma.

STAT3 activation accompanies keratinocyte differentiation

The signal transducers and activators of transcription (STAT) family of transcription factors has been demonstrated to play key roles in a variety of cell types under conditions that promote differentiation or cell cycle exit. We report our studies of primary murine keratinocytes in which we demonstrate activation of STAT3 during growth arrest and differentiation. In adherent cells, STAT3-specific DNA binding activity was detected in quiescent cultures, down-regulated upon mitogenic stimulation, and found to reaccumulate as cells reentered quiescence. Suspension culturing of proliferating keratinocytes, which induces differentiation, also resulted in induction of STAT3 activity. Furthermore, induction of STAT3 after suspension culturing did not occur in MK cells, an immortalized murine keratinocyte cell line that does not undergo differentiation. Because STAT3 activation in these cells corresponded tightly with the growth status, we examined whether there was a relationship between the cell cycle machinery and STAT3 activation by inhibiting p27kip1 accumulation, which is observed during growth arrest, with antisense oligonucleotides and by using keratinocytes lacking functional p27kip1. In both cases, there was a loss of STAT3 activation and a concomitant delay in terminal cell cycle withdrawal and in the expression of the differentiation specific marker, keratin 1. Thus, in addition to controlling transcription mediated through E2F, our data demonstrate that alterations in the cell cycle machinery are required for appropriate up-regulation of STAT3 activity that occurs during keratinocyte differentiation.

The aging population. A critical issue in medicine for the 21st century

One critical issue facing medical science concerns the aging population. The number of individuals 65 years and older has increased during the past decade and likely will double by the year 2030, when the elderly will represent nearly 20% of the total population. This dramatic increase has numerous ramifications; health care is of utmost importance. Inherent in meeting the medical needs of these individuals is a fundamental understanding of the effects of aging on the functional integrity of numerous organ systems. In recognition of this problem, the Department of Pharmacology and Therapeutics at the University of South Florida College of Medicine has initiated a major effort focused on age-related research. The objectives are to elucidate fundamental biochemical, physiological, and pharmacological alterations that occur as a consequence of normal aging and to investigate the role of these perturbations on the manifestations of disease. Information gained from such studies will provide a rational approach in developing therapeutic strategies for the treatment of diseases affecting older citizens. This article presents a brief overview of four areas of research currently being pursued. These include aging and brain function, age-related alterations in drug metabolism, aging and smooth muscle function, and the effects of aging on the immune system.