Faculty Bibliography

OBJECTIVES: (1) Present a unique case of a thyroglossal duct cyst (TGDC) excised for recurrent infections with Trichinella spiralis in adjacent strap muscle; (2) review the literature regarding the diagnosis and treatment of subclinical trichinellosis of the head and neck. STUDY DESIGN: Case report and literature review. METHODS: Case report and literature review. RESULTS: We present the case of a male immigrant who suffered from recurrent midline neck infections due to aTGDC. The patient underwent an uneventful Sistrunk procedure. Histological examination of the surgical specimen revealed a chronically infected TGDC as well as remnants of skeletal muscle adjacent to the cyst containing nematode larvae, positively identified as Trichinella spiralis. The patient was subsequently evaluated by an infectious disease specialist and required no further treatment for his parasitic infection. DISCUSSION: The presence of nematode infections in developed countries is rare today given improved hygiene practices and control of meat quality. We present a unique case of incidentally noted Trichinella spiralis infection of the head and neck. To our knowledge, this is the first described case of trichinellosis of strap muscle adjacent to an excised TGDC and furthermore highlights the rarity of Trichinella spiralis infections of the head and neck. CONCLUSIONS: Trichinella spiralis may exist subclinically in a variety of human tissues including neck muscles

Selenium (Se) supplementation is reported to decrease the incidence and total mortality of cancer. Whereas in vitro and in vivo studies have shown a decrease in prostate, lung, and liver cancers, this has not been shown in thyroid cancer. ARO (anaplastic), NPA (BRAF positive papillary), WRO (BRAF negative papillary), and FRO (follicular) cells treated with 150 microM seleno-l-methionine (SM) were assessed for viability at 24, 48, and 72 h. Treated FRO cells were examined for cell cycle using flow cytometry, for apoptosis using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, and for gene expression using microarray. Genes identified as upregulated were confirmed by real-time PCR (RT-PCR) and proteins by Western blot analysis. SM treatment significantly decreased the proliferation of all cell lines. TUNEL assay showed no evidence of apoptosis, and flow cytometry showed a significant cell-cycle arrest in S (271% increase, P = 0.006) and G2/M (61% increase, P = 0.002) compared to control. Microarray revealed 21 differentially expressed genes with greater than twofold change. A relative overexpression of growth arrest and DNA damage inducible (GADD)34 and GADD153 in treated cells was confirmed with RT-PCR and Western blot. SM inhibits thyroid cancer cell proliferation through a time dependent upregulation of the GADD family of genes and arrest in S and G2/M phases of the cell cycle. This is the first report of selenium induced inhibition of thyroid cancer cell growth.

Purpose: Cutaneous radiation injury occurs during the treatment of cancer, or in rare environmental exposure. As the acute wound heals, fibrosis is induced and extracellular matrix (ECM) is deposited. The fibrotic pathway is mediated by the transforming growth factor-beta (TGF-beta) cascade, and is dependent on Smad3, a transcription factor for ECM. We characterized gene expression of this cascade after radiation injury and performed in vitro and in vivo gene silencing of Smad3 in an attempt to reverse the fibrotic pathway. Methods: Wild-type murine dermal fibroblasts were irradiated with 20Gy and harvested at serial time-points. RT-PCR was performed for known regulators and mediators of fibrosis. Smad3 was silenced by transfection with siRNA. For the in vivo experiment, dorsal skin of wild-type mice was irradiated with 45 Gy. Five weeks later, siRNA was applied to the fibrotic areas for one week. Skin was harvested and tissue analyzed by RT-PCR and Western blotting, as well as tissue tensiometry, which quantitatively measures rigidity. Results: Following irradiation, there was a steady increase in mRNA expression of Smad3, TGFbeta, and ECM genes collagen 1A1, metalloprotease2, and tissue inhibitor of metalloprotease-1, with peak expression at 12-24 hours. Inhibition of Smad3 with siRNA significantly decreased expression of Smad3, TGFbeta, and ECM genes. In the mouse model, topical treatment with siRNA again significantly decreased expression of these genes. Tensiometry demonstrated decreased stiffness in Smad3 siRNA treated skin, with a Young's modulus nearer to normalcompared to untreated and nonsense siRNA treated skin. Conclusion: Following initiation of the fibrotic pathway by radiation, Smad3 siRNA treatment both in vitro and in vivo effectively reversed gene expression. Furthermore, cutaneous Smad3 inhibition mitigated radiation-induced fibrotic stiffening. These findings suggest a therapeutic role for Smad3 silencing for cancer patients treated with radiation as well as those accidentally exposed to radiation

The positive results of the performance of zirconia for orthopedics devices have led the dental community to explore possible esthetical and mechanical outcomes using this material. However, questions regarding long-term results have opened strong and controversial discussions regarding the utilization of zirconia as a substitute for alloys for restorations and implants. This narrative review presents the current knowledge on zirconia utilized for dental restorations, oral implant components, and zirconia oral implants, and also addresses laboratory tests and developments, clinical performance, and possible future trends of this material for dental healthcare.