Chemonucleolysis combined with dynamic loading for inducing degeneration in bovine caudal intervertebral discs.

Chemonucleolysis has become an established method of producing whole organ culture models of intervertebral disc (IVD) degeneration. However, the field needs more side-by-side comparisons of the degenerative effects of the major enzymes used in chemonucleolysis towards gaining a greater understanding of how these organ culture models mimic the wide spectrum of characteristics observed in human degeneration. In the current work we induced chemonucleolysis in bovine coccygeal IVDs with 100 µL of papain (65 U/mL), chondroitinase ABC (chABC, 5 U/mL), or collagenase II (col'ase, 0.5 U/mL). Each enzyme was applied in a concentration projected to produce moderate levels of degeneration. After 7 days of culture with daily dynamic physiological loading (0.02-0.2 MPa, 0.2 Hz, 2 h), the cellular, biochemical and histological properties of the IVDs were evaluated in comparison to a PBS-injected control. Papain and collagenase, but not chABC, produced macroscopic voids in the tissues. Compared to day 0 intact IVDs, papain induced the greatest magnitude glycosaminoglycan (GAG) loss compared to chABC and col'ase. Papain also induced the greatest height loss (3%), compared to 0.7%, 1.2% and 0.4% for chABC, col'ase, and PBS, respectively. Cell viability in the region adjacent to papain and PBS-injection remained at nearly 100% over the 7-day culture period, whereas it was reduced to 60%-70% by chABC and col'ase. Generally, enzyme treatment tended to downregulate gene expression for major ECM markers, type I collagen (COL1), type II collagen (COL2), and aggrecan (ACAN) in the tissue adjacent to injection. However, chABC treatment induced an increase in COL2 gene expression, which was significant compared to the papain treated group. In general, papain and col'ase treatment tended to recapitulate aspects of advanced IVD degeneration, whereas chABC treatment captured aspects of early-stage degeneration. Chemonucleolysis of whole bovine IVDs is a useful tool providing researchers with a robust spectrum of degenerative changes and can be utilized for examination of therapeutic interventions.

Cyst of the canal of Nuck: an atypical course with cyclic changing of size.

As the canal of Nuck normally obliterates before birth, a patent canal is a rare anatomic variant in adult women analogue to the patent processus vaginalis in men. In a patent canal of Nuck, pathologies such as hernias and cyst can build within time. Such cysts themselves are so uncommon that they are mostly described in case reports. Normally, cysts of the canal of Nuck present as a consistent, inguinal swelling with or without pain. Interestingly, in our case, the painful swelling was cyclic changing from the size of a plum to being clinically undetectable within the course of a day. To the best of our knowledge, this is the first description of such an unusual course. The cyst was removed operatively via an open approach. The spasms declined shortly after the operation. At 1 year postoperatively, the patient was still asymptomatic.

Severity of degenerative lumbar spinal stenosis affects pelvic rigidity during walking.

BACKGROUND CONTEXT: To understand the role of compensation mechanisms in the development and treatment of symptomatic degenerative lumbar spinal stenosis (DLSS), pelvic stability during walking should be objectively assessed in the context of clinical parameters. PURPOSE: To determine the association among duration of symptoms, lumbar muscle atrophy, disease severity, pelvic stability during walking, and surgical outcome in patients with DLSS scheduled for decompression surgery. STUDY DESIGN/SETTING: Prospective observational study with intervention. PATIENT SAMPLE: Patients with symptomatic DLSS. OUTCOME MEASURES: Oswestry Disability Index score; duration of symptoms; lumbar muscle atrophy; severity grade; pelvis rigidity during walking. METHODS: Patients with symptomatic DLSS were analyzed on the day before surgery and 10 weeks and 12 months postoperatively. Duration of symptoms was categorized as: <2years, <5years, and >5years. Muscle atrophy at the stenosis level was categorized according to Goutallier. Bilateral cross-sectional areas of the erector spinae and psoas muscles were quantified from magnetic resonance imaging. Stenosis grade was assessed using the Schizas classification. Pelvic tilt was measured in standing radiographs. Pelvic rigidity during walking was assessed as root mean square of the pelvic acceleration in each direction (anteroposterior, mediolateral, and vertical) normalized to walking speed measured using an inertial sensor attached to the skin between the posterior superior iliac spine. RESULTS: Body mass index but not duration of symptoms, lumbar muscle atrophy, pelvic rigidity, and stenosis grade explained changes in Oswestry Disability Index from before to after surgery. Patients with greater stenosis grade had greater pelvic rigidity during walking. Lumbar muscle atrophy did not correlate with pelvic rigidity during walking. Patients with lower stenosis grade had greater muscle atrophy and patients with smaller erector spinae and psoas muscle cross-sectional areas had a greater pelvis tilt. CONCLUSIONS: Greater pelvic rigidity during walking may represent a compensatory mechanism of adopting a protective body position to keep the spinal canal more open during walking and hence reduce pain. Pelvic rigidity during walking may be a useful screening parameter for identifying early compensating mechanisms. Whether it can be used as a parameter for personalized treatment planning or outcome prognosis necessitates further evaluation.

Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro.

Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation.