Extensive Connections of the Canine Olfactory Pathway Revealed by Tractography and Dissection.

The olfactory sense of the domestic dog is widely recognized as being highly sensitive with a diverse function; however, little is known about the structure of its olfactory system. This study examined a cohort of mixed-sex mesaticephalic canines and used diffusion tensor imaging (DTI), an MRI technique, to map connections from the olfactory bulb to other cortical regions of the brain. The results were validated using the Klingler dissection method. An extensive pathway composed of five white matter tracts connecting to the occipital lobe, cortical spinal tract, limbic system, piriform lobe, and entorhinal pathway was identified. This is the first documentation of a direct connection between the olfactory bulb and occipital lobe in any species and is a step toward further understanding how the dog integrates olfactory stimuli into their cognitive function.SIGNIFICANCE STATEMENT The highly sensitive olfactory system of the domestic dog is largely unexplored. We applied diffusion tractography and dissection techniques to evaluate the white matter connections associated with the olfactory system in a large cohort of dogs. We discovered an extensive white matter network extending from the olfactory bulb to form novel connections directly to other cortices of the brain. This is the first documentation of these novel olfactory connections and provides new insight into how dogs integrate olfactory stimuli in their cognitive functioning.

Interleukin-22 promotes intestinal-stem-cell-mediated epithelial regeneration.

Epithelial regeneration is critical for barrier maintenance and organ function after intestinal injury. The intestinal stem cell (ISC) niche provides Wnt, Notch and epidermal growth factor (EGF) signals supporting Lgr5(+) crypt base columnar ISCs for normal epithelial maintenance. However, little is known about the regulation of the ISC compartment after tissue damage. Using ex vivo organoid cultures, here we show that innate lymphoid cells (ILCs), potent producers of interleukin-22 (IL-22) after intestinal injury, increase the growth of mouse small intestine organoids in an IL-22-dependent fashion. Recombinant IL-22 directly targeted ISCs, augmenting the growth of both mouse and human intestinal organoids, increasing proliferation and promoting ISC expansion. IL-22 induced STAT3 phosphorylation in Lgr5(+) ISCs, and STAT3 was crucial for both organoid formation and IL-22-mediated regeneration. Treatment with IL-22 in vivo after mouse allogeneic bone marrow transplantation enhanced the recovery of ISCs, increased epithelial regeneration and reduced intestinal pathology and mortality from graft-versus-host disease. ATOH1-deficient organoid culture demonstrated that IL-22 induced epithelial regeneration independently of the Paneth cell niche. Our findings reveal a fundamental mechanism by which the immune system is able to support the intestinal epithelium, activating ISCs to promote regeneration.

Parathyroid carcinoma presenting with pathologic fracture: case report and review of the literature.

BACKGROUND: Parathyroid carcinoma is a rare neoplasm representing <1% of primary hyperparathyroidism cases. It is often not diagnosed until surgical exploration as a preoperative diagnosis is often not possible. Thus, preoperative staging for most patients is not feasible and this may compromise the treatment strategy. METHODS AND RESULTS: We report a case of a 29-year-old man presenting with avulsion fracture of the right elbow after a trivial fall. Neck exploration revealed an enlarged left lobe focally adherent to the larynx and trachea. Final pathology revealed parathyroid carcinoma with focally positive margin at the site of tracheal invasion. CONCLUSION: Parathyroid carcinoma is a rare cause of primary hyperparathyroidism. The etiology of parathyroid carcinoma is usually obscured, and the initial operation offers the best chance for cure.

Atypical presentation of mucoepidermoid carcinoma after radiation therapy for the treatment of keloids.

Radiation therapy to the head and neck for the treatment of benign diseases carries the potential for the late development of carcinoma. Low-dose radiation has been used as an adjunctive treatment for recurrent keloids, especially massive keloids, but the carcinogenic potential of ionizing radiation in this setting remains controversial. We report the case of a 37-year-old black woman with a history of severe earlobe keloids who had been first treated with resection and postoperative radiation at the age of 9 years. When she had reached the age of 36 years, she required reoperation for massive keloid scarring, after which she underwent a second course of postoperative radiation to the right side of her face and neck. Some 20 months after the second administration of radiation therapy, she developed a mucoepidermoid carcinoma in the right parotid gland. The tumor was successfully treated with surgery.