Increase in serum nerve growth factor but not intervertebral disc degeneration following whole-body vibration in rats.

BACKGROUND: Low back pain is a leading cause of disability and is frequently associated with whole-body vibration exposure in industrial workers and military personnel. While the pathophysiological mechanisms by which whole-body vibration causes low back pain have been studied in vivo, there is little data to inform low back pain diagnosis. Using a rat model of repetitive whole-body vibration followed by recovery, our objective was to determine the effects of vibration frequency on hind paw withdrawal threshold, circulating nerve growth factor concentration, and intervertebral disc degeneration. METHODS: Male Sprague-Dawley rats were vibrated for 30 min at an 8 Hz or 11 Hz frequency every other day for two weeks and then recovered (no vibration) for one week. Von Frey was used to determine hind paw mechanical sensitivity every two days. Serum nerve growth factor concentration was determined every four days. At the three-week endpoint, intervertebral discs were graded histologically for degeneration. FINDINGS: The nerve growth factor concentration increased threefold in the 8 Hz group and twofold in the 11 Hz group. The nerve growth factor concentration did not return to baseline by the end of the one-week recovery period for the 8 Hz group. Nerve growth factor serum concentration did not coincide with intervertebral disc degeneration, as no differences in degeneration were observed among groups. Mechanical sensitivity generally decreased over time for all groups, suggesting a habituation (desensitization) effect. INTERPRETATION: This study demonstrates the potential of nerve growth factor as a diagnostic biomarker for low back pain due to whole-body vibration.

Mitochondrial dysfunctions, endothelial progenitor cells and diabetic retinopathy.

AIM: Diabetic retinopathy (DR) is the leading cause of vision loss in the working age population. Endothelial progenitor cells (EPC) play a vital role in vascular damage repair. This article will review recent progress regarding mitochondrial and EPC dysfunction associated with DR. RESULTS: EPCs represent a limited population of adult stem cells possessing vasculogenic potential postnatally; their number and function are changed in DR. Among all the function changes, mitochondrial dysfunction plays an important role in the dysregulation of EPCs, as mitochondria regulate energy balance, and cell fate determination. CONCLUSIONS: Although the mechanism for the role of mitochondria dysregulation in EPC function remains elusive, mitochondria of EPCs represent a promising target for the treatment of the vasculopathy presented within DR.

Development of cholesterol granuloma in a temporal bone petrous apex previously containing marrow exposed to air cells.

OBJECTIVE: There is ongoing debate on the pathogenic mechanisms of cholesterol granuloma formation in the temporal bone. The purpose of this report is to provide evidence in support of the exposed marrow hypothesis in explaining the pathogenesis of petrous apex cholesterol granuloma. STUDY DESIGN: Retrospective single case study. MAIN OUTCOME MEASUREMENT: The primary outcome evaluated was the diagnosis of a new cholesterol granuloma in a petrous apex that previously demonstrated radiologic evidence of bone marrow exposed to petrous apex air cells. RESULTS: A patient with a unilateral petrous apex cholesterol granuloma develops a new, contralateral cholesterol granuloma in a hyperpneumatized temporal bone petrous apex shown previously to have medullary bone exposed to air cells. CONCLUSION: This report implicates the medullary-air cell interface in a hyperaerated temporal bone petrous apex in the development and growth of a petrous apex cholesterol granuloma.

Preoperative testing for radial forearm free flaps to reduce donor site morbidity.

OBJECTIVE: To compare the clinical Allen test, preoperative Doppler ultrasonography, and intraoperative surgical Allen test with postoperative clinical findings in reconstruction of complex head and neck defects using radial forearm free flaps. DESIGN, SETTING, AND PATIENTS: Retrospective review of 143 consecutive patients who underwent radial forearm free flap reconstruction from January 1, 1992, through December 31, 2006, at Vanderbilt University Medical Center. RESULTS: Flap survival rate was 96.4%. No patients experienced digital necrosis or other findings of acute ischemia. Two patients (1.9%) who had normal results of clinical and surgical Allen tests developed hand contracture and palmar nodule formation. Surgical Allen test findings were normal in all patients who underwent reconstruction. Eighty-two arms had documentation of clinical Allen testing and Doppler ultrasonography in the patients' medical records. Agreement between these measures was 92.7%. The clinical Allen test result was 100% sensitive and 75% specific in predicting an abnormal Doppler ultrasonographic finding. CONCLUSIONS: The clinical Allen test is an appropriate preoperative evaluation before radial forearm free flap reconstruction. The addition of Doppler ultrasonography should be limited to patients with abnormal clinical Allen test results. The surgical Allen test provides reassurance but does not preclude the possibility of ischemic hand complications.

Efficacy of transnasal endoscopic resection for malignant anterior skull-base tumors.

BACKGROUND: Craniofacial resection (CFR) has been the standard of care for malignant tumors of the anterior skull base (ASB). However, during the past 2 decades, transnasal endoscopic resection (TER) has gained significant popularity. The purpose of this study is to compare CFR and TER with respect to perioperative and oncologic outcomes. METHODS: Retrospective analysis at a tertiary care medical center of 82 consecutive patients undergoing resection of tumors of the ASB between 1997 and 2011. RESULTS: Thirty-four patients underwent TER, while 48 patients underwent CFR. There was no statistical difference in major complications between the two groups (p = 0.29). However, TER patients had shorter operating room times (284 minutes for TER, 620 minutes for CFR; p < 0.001), lower intraoperative blood loss (675 mL for TER, 1000 mL for CFR; p = 0.005), shorter intensive care unit (ICU) stays (0 days for TER, 3 days for CFR; p < 0.001), and shorter hospital stays (4.5 days for TER; 7 days for CFR; p < 0.001). There were no differences for the rates of en bloc resection, negative margins, or disease-specific mortality. Subanalysis yielded a median follow-up of 5 years postoperatively. There were no differences in disease-specific mortality or recurrences in this group. CONCLUSION: Patients undergoing TER for tumors of the ASB are more likely to leave the ICU and the hospital earlier than their CFR counterparts. Furthermore, for carefully selected patients undergoing TER, excellent oncologic outcomes with survival and recurrence rates similar to patients undergoing CFR may be achieved. Comparison of oncologic outcomes, however, may be limited by discrepancy in histologic grade and clinical stage between the two groups. Nonetheless, TER seems to be an excellent alternative to CFR in appropriately selected patients.

Inverted papillomas and benign nonneoplastic lesions of the nasal cavity.

BACKGROUND: Benign lesions of the nasal cavity represent a diverse group of pathologies. Furthermore, each of these disorders may present differently in any given patient as pain and discomfort, epistaxis, headaches, vision changes, or nasal obstruction. Although these nasal masses are benign, many of them have a significant capacity for local tissue destruction and symptomatology secondary to this destruction. Advances in office-based endoscopic nasendoscopy have equipped the otolaryngologist with a safe, inexpensive, and rapid means of directly visualizing lesions within the nasal cavity and the initiation of appropriate treatment. METHODS: The purpose of this study is to review the diagnosis, management, and controversies of many of the most common benign lesions of the nasal cavity encountered by the primary care physician or otolaryngologist. RESULTS: This includes discussion of inverted papilloma (IP), juvenile angiofibroma, squamous papilloma, pyogenic granuloma, hereditary hemorrhagic telangiectasia, schwannoma, benign fibro-osseous lesions, and other benign lesions of the nasal cavity, with particular emphasis on IP and juvenile angiofibroma. CONCLUSION: A diverse array of benign lesions occur within the nasal cavity and paranasal cavities. Despite their inability to metastasize, many of these lesions have significant capability for local tissue destruction and recurrence.

An accurate and stable nitrate-selective electrode for the in situ determination of nitrate in agricultural drainage waters.

A field evaluation of a novel nitrate-ion selective electrode (ISE) was undertaken by continuous immersion over a period of 5 months in agricultural drainage weirs. The nitrate sensor N,N,N-triallyl leucine betaine was covalently attached to polystyrene-block-polybutadiene-block-polystyrene (SBS) using a free radical initiated co-polymerisation, to produce a rubbery membrane which was incorporated into a commercially available electrode body. A measurement unit was constructed comprising the nitrate-ISEs, a reference electrode and a temperature probe connected through a pre-amplifier to a data-logger and battery supply. A temperature correction algorithm was developed to accomodate the temperature changes encountered in the drainage weirs. The nitrate results obtained with the ISEs at hourly intervals compared very favourably (R2 = 0.99) with those obtained with laboratory automated chemical determinations made on contemporaneous samples of drainage in a concentration range 0.47-16 ppm nitrate-N. The ISEs did not require re-calibration and no deterioration in performance or fouling of the membrane surface was observed over four months of deployment.