SoxD Transcription Factors: Multifaceted Players of Neural Development.

SoxD transcription factor subfamily includes three members, Sox5, Sox6, and Sox13. Like other Sox genes, they contain the High-Mobility-Group (HMG) box as the DNA binding domain but in addition feature the subgroup-specific leucine zipper motif. SoxD genes are expressed in diverse cell types in multiple organs during embryogenesis and in adulthood. Among the cells expressing them are those present in the developing nervous system including neural stem (or progenitor) cells as well as differentiating neurons and oligodendrocytes. SoxD transcription factors do not contain distinct activator or repressor domain, and they are believed to function in modulation of other transcription factors in promoter-specific manners. This brief review article will attempt to summarize the latest studies on the function of SoxD genes in embryogenesis with a particular emphasis on the regulation of neural development.

Positive feedback loop between Sox2 and Sox6 inhibits neuronal differentiation in the developing central nervous system.

How a pool of undifferentiated neural progenitor cells is maintained in the developing nervous system is an issue that remains unresolved. One of the key transcription factors for self-renewal of these cells is Sox2, the forced expression of which has been shown to inhibit neuronal differentiation in vivo. To dissect the molecular mechanisms of Sox2 activity, a ChIP-on-chip assay has been carried out for Sox2, and multiple candidate direct target genes have been isolated. In this report, we provide evidence indicating that Sox6, which like Sox2 belongs to the SRY-related HMG box transcription factor family, is a bona-fide direct regulatory target of Sox2. In vivo, Sox6 expression is seen with a temporal lag in Sox2-positive neural precursor cells in the ventricular zone, and Sox2 promotes expression of Sox6 as a transcriptional activator. Interestingly, gain- and loss-of-function assays indicate that Sox6 in turn is required for the maintenance of Sox2 expression, suggesting that a positive feedback loop, which functions to inhibit premature neuronal differentiation, exists between the two transcription factors.

Viability of pulp stromal cells in cryopreserved deciduous teeth.

The cryopreservation of exfoliated deciduous teeth and harvesting of stem cells from them as required would reduce the costs and efforts associated with banking stem cells from primary teeth. The aim of this study was determine whether the viability of pulp stromal cells from deciduous teeth was influenced by the cryopreservation process itself or the period of cryopreservation. In total, 126 deciduous teeth were divided into three groups: (1) fresh, (2) cryopreserved for <3 months (cryo<3), and (3) cryopreserved for 3-9 months (cryo3-9). The viability of the pulp tissues was compared among the three groups by evaluating the outgrowth from pulp tissues and cell activity within those pulp tissues. In addition, the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay was performed to compare cell apoptosis within fresh pulp tissue and pulp tissue that had been cryopreserved for 4 months. The outgrowth from and cell activity within the pulp tissues did not differ significantly between the fresh and cryo<3 pulp tissues. However, these parameters were significantly reduced in the cryo3-9 pulp tissue. In TUNEL assay, 4-month cryopreserved pulp tissues has more apoptotic cells than fresh group. In conclusion, it is possible to acquire pulp stromal cells from cryopreserved deciduous teeth. However, as the period of cryopreservation becomes longer, it is difficult to get pulp cells due to reduced cell viability.

A case of typhlitis developed after chemotherapy with irinotecan and Cisplatin in a patient with small cell lung carcinoma.

Typhlitis is a necrotizing colitis that usually occurs in neutropenic patients and develops most often in patients with hematologic malignancies such as leukemia and lymphoma. Typhlitis may proceed to bowel perforation, peritonitis and sepsis, which requires immediate treatment. Irinotecan is a semisynthetic analogue of the natural alkaloid camptothecin which prevents DNA from unwinding by inhibition of topoisomerase I. It is mainly used in colon cancer and small cell lung carcinoma (SCLC), of which the most common adverse effects are gastrointestinal toxicities. To the best of our knowledge, no case of typhlitis after chemotherapy with a standard dose of irinotecan in a solid tumor has been reported in the literature. We, herein, report the first case of typhlitis developed after chemotherapy combining irinotecan and cisplatin in a patient with SCLC.

Rapidly Progressive Cardiac Manifestation of Behçet's Disease Involving Conduction System and Aortic Valve.

Cardiac conduction system impairment is a rare clinical manifestation of Behçet's disease. We report a patient who showed 1st degree atrioventricular block at first presentation, and showed aggravated finding of 3rd degree atrioventricular block on five months later. His cardiac manifestation finally developed to acute severe aortic regurgitation on six months later from his first cardiac manifestation. We observed this rapid progression during 6 months and successfully improved symptom and disease severity of the patient with treatment targeting Behçet's disease.