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Open Access Publications from the University of California


The Department of Otolaryngology Head and Neck Surgery at the UC Davis Medical Center provides comprehensive services to patients residing in the Northern California region extending from southern Oregon south to Fresno, east to Nevada and west to the San Francisco Bay Area.

We are a teaching institution that provides care in the following areas: general otolaryngology, head and neck cancer, skull base surgery, otology/neurotology, facial plastics and reconstructive surgery, rhinology, pediatric otolaryngology, craniofacial and cleft palate/lip surgery, and laryngology.

Department of Otolaryngology, Head and Neck Surgery

There are 50 publications in this collection, published between 2009 and 2021.
Open Access Policy Deposits (50)

Immunoregulatory Potential of Exosomes Derived from Cancer Stem Cells.

Head and neck squamous cell carcinomas (HNSCCs) are malignancies that originate in the mucosal lining of the upper aerodigestive tract. Despite advances in therapeutic interventions, survival rates among HNSCC patients have remained static for years. Cancer stem cells (CSCs) are tumor-initiating cells that are highly resistant to treatment, and are hypothesized to contribute to a significant fraction of tumor recurrences. Consequently, further investigations of how CSCs mediate recurrence may provide insights into novel druggable targets. A key element of recurrence involves the tumor's ability to evade immunosurveillance. Recent published reports suggest that CSCs possess immunosuppressive properties, however, the underlying mechanism have yet to be fully elucidated. To date, most groups have focused on the role of CSC-derived secretory proteins, such as cytokines and growth factors. Here, we review the established immunoregulatory role of exosomes derived from mixed tumor cell populations, and propose further study of CSC-derived exosomes may be warranted. Such studies may yield novel insights into new druggable targets, or lay the foundation for future exosome-based diagnostics.

Advances in bone marrow stem cell therapy for retinal dysfunction.

The most common cause of untreatable vision loss is dysfunction of the retina. Conditions, such as age-related macular degeneration, diabetic retinopathy and glaucoma remain leading causes of untreatable blindness worldwide. Various stem cell approaches are being explored for treatment of retinal regeneration. The rationale for using bone marrow stem cells to treat retinal dysfunction is based on preclinical evidence showing that bone marrow stem cells can rescue degenerating and ischemic retina. These stem cells have primarily paracrine trophic effects although some cells can directly incorporate into damaged tissue. Since the paracrine trophic effects can have regenerative effects on multiple cells in the retina, the use of this cell therapy is not limited to a particular retinal condition. Autologous bone marrow-derived stem cells are being explored in early clinical trials as therapy for various retinal conditions. These bone marrow stem cells include mesenchymal stem cells, mononuclear cells and CD34+ cells. Autologous therapy requires no systemic immunosuppression or donor matching. Intravitreal delivery of CD34+ cells and mononuclear cells appears to be tolerated and is being explored since some of these cells can home into the damaged retina after intravitreal administration. The safety of intravitreal delivery of mesenchymal stem cells has not been well established. This review provides an update of the current evidence in support of the use of bone marrow stem cells as treatment for retinal dysfunction. The potential limitations and complications of using certain forms of bone marrow stem cells as therapy are discussed. Future directions of research include methods to optimize the therapeutic potential of these stem cells, non-cellular alternatives using extracellular vesicles, and in vivo high-resolution retinal imaging to detect cellular changes in the retina following cell therapy.

Diagnosis and Management of Depression in CRS: A Knowledge, Attitudes and Practices Survey.

Introduction  Comorbid major depressive disorder (MDD) is present in up to 25% of chronic rhinosinusitis (CRS) cases and provides prognostic information for patients undergoing endoscopic sinus surgery (ESS). Clinical visits offer an opportunity to identify at-risk patients. Objective  The purpose of the present study is to evaluate practice patterns among members of the American Rhinologic Society (ARS) in screening for/diagnosing MDD. Methods  A 21-question survey was distributed to 1,206 members of the ARS from May 26, 2018 to June 12, 2018. The impact of demographic factors, including hospital setting, fellowship status, and experience were assessed through chi-squared analysis. Results  A total of 80 members of the ARS completed the survey, yielding a response rate of 7%. Half of the respondents worked in academic settings and 43% had completed a rhinology fellowship. Twenty percent of the participants felt comfortable diagnosing or managing MDD, while only 10% of participants screened for MDD in patients with CRS. Respondents cited a lack of training (76%) and unfamiliarity with diagnostic criteria (76%) as barriers to the routine assessment of MDD. Most respondents (95%) considered comorbid psychiatric illness to negatively impact outcomes following ESS. Fellowship-trained respondents were significantly more likely to implement screening tools in their practice ( p  = 0.05), and believe in the negative impact of MDD on postoperative outcomes ( p  = 0.007), cost of care ( p  = 0.04) and quality of life ( p  = 0.047). Conclusion  Amongst ARS members, 95% of the respondents consider comorbid MDD to negatively impact patient outcomes following ESS. Regardless, a large proportion of surgeons neither screen nor feel comfortable diagnosing MDD.

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