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Background: Localization of ectopic parathyroid glands is one of the most sophisticated challenges in endocrine surgery and there is considerable controversy regarding the suitable approach to localize ectopic parathyroid glands and indications for using different modalities. The failure of the first operation leads to pain, scar, and financial burden of the following operation. Case: The patient was a 39-year-old woman hospitalized with hematuria as the main complaint and noticing the presentation of hypercalcemia in the initial tests underwent more thorough examination. Ultrasonography and 99mTc sestamibi scan helped us to localize the ectopic parathyroid gland in an anterior mediastinum and treat the patient in a one stage operation. Conclusion: Paying careful attention to the symptoms and signs, considering all differential diagnoses, and using appropriate diagnostic methods can be helpful in the diagnosis of rare syndromes.

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Background: Retinoic acid (RA) is a vitamin A derivative and one of the most important inducing signals in vertebrates that is involved in differentiation, morphogenesis, apoptosis, and reproduction. This study was done to evaluate the role of RA in in vitro neural patterning of mouse embryonic stem cells (mESCs).

Materials and Methods: In this experimental study, upon formation, embryoid bodies (EBs) from mESCs, Royan B1, were induced by 1 µM RA for four days and then plated for eight days. Untreated EBs were considered as the control group. Finally, in both groups, neural induction and patterning of EB-derived neural cells were evaluated by using immunostaining, flowcytometry, and RT-PCR methods.

Results: RA induced neurogenesis in ES cells, from which 35% showed to express MAP2. RT-PCR analysis also indicated that RA-treated neural cells derived from ES cells could at the same time express Mash1, Pax6/7, and Dbx1/2 as dorso-ventral (DV) pattering markers and Hoxb4, Hoxc5, and Hoxc8 as the rostro-caudal (RC) axis markers.

Conclusion: RA induces in vitro neural induction along with neural patterning of ES-derived neural cells in DV and RC axes. Keywords: Mouse embryonic stem cells, neural patterning, retinoic acid