Survival of hypoxic human mesenchymal stem cells is enhanced by a positive feedback loop involving miR-210 and hypoxia-inducible factor 1

The use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for myocardial infarction. However, the poor viability of MSCs after transplantation critically limits the efficacy of this new strategy. The expression of microRNA-210 (miR-210) is induced by hypoxia and is important for cell survival under hypoxic conditions. Hypoxia increases the levels of hypoxia inducible factor-1 (HIF-1) protein and miR-210 in human MSCs (hMSCs). miR-210 positively regulates HIF-1alpha activity. Furthermore, miR-210 expression is also induced by hypoxia through the regulation of HIF-1alpha. To investigate the effect of miR-210 on hMSC survival under hypoxic conditions, survival rates along with signaling related to cell survival were evaluated in hMSCs over-expressing miR-210 or ones that lacked HIF-1alpha expression. Elevated miR-210 expression increased survival rates along with Akt and ERK activity in hMSCs with hypoxia. These data demonstrated that a positive feedback loop involving miR-210 and HIF-1alpha was important for MSC survival under hypoxic conditions.

Assessment of Di (2-ethylhexyl) Phthalate Exposure by Urinary Metabolites as a Function of Sampling Time / 예방의학회지

OBJECTIVES: In most DEHP exposure assessment studies, single spot urine sample was used. It could not compare the exposure level among studies. Therefore, we are going to represent the necessity of selection of proper sampling time of spot urine for assessing the environmental DEHP exposure, and the association urinary DEHP metabolites with steroid hormones. METHODS: We collected urine and plasma from 25 men. The urine sampling times were at the end of the shift (post-shift) and the next morning before the beginning of the shift (pre-shift). Three metabolites of DEHP {mono(2-ethylhexyl) phthalate [MEHP], mono-(2-ethyl-5-hydroxyhexyl)phthalate [MEHHP], and mono(2-ethyl-5-oxohexyl)phthalate [MEOHP]} in urine were analyzed by HPLC/MS/MS. Plasma luteinzing hormone, follicle stimulating hormone, testosterone, and 17beta-estradiol were measured at pre-shift using a ELISA kit. A log-transformed creatinine-adjusted urinary MEHP, MEHHP, and MEOHP concentration were compared between the post- and pre-shift. The Pearson's correlation was calculated to assess the relationships between log-transformed urinary MEHP concentrations in pre-shift urine and hormone levels. RESULTS: The three urinary metabolite concentrations at post-shift were significantly higher than the concentrations in the pre-shift (p<0.0001). The plasma hormones were not significantly correlated with log-transformed creatinine - adjusted DEHP metabolites. CONCLUSIONS: To assess the environmental DEHP exposure, it is necessary to select the urine sampling time according to the study object. There were no correlation between the concentration of urinary DEHP metabolites and serum hormone levels.

A Case of Congenital Cholesteatoma : Combined with Ossicular Anomaly / 대한이비인후과학회지

Congenital middle ear cholesteatoma is presented as a pearl-like-material behind an intact tympanic membrane. Congenital cholesteatoma can be associated with other congenital anomalies, especially ossicular anomalies. The patient was a 10-year-old male with incidentally known hearing disturbance with intact tympanic membrane. The pure tone average through air conduction of his left ear was 55dB. During exploratory tympanotomy, congenital cholesteatoma was found in the middle ear cavity in a scattered pattern and fibrous stapes was located below the oval window with an intact stapedial footplate. We removed cholesteatoma matrix and performed ossiculoplasty with total ossicular replacement prosthesis (TORP). After 1 month, the postoperative pure tone average through air conduction of the left ear was 33dB. We report one case of congenital middle ear cholesteatoma with congenital ossicular anomaly with a review of the related literature.

Decreased Serum Immunoglobulin in Recurrent Otitis Media with Effusion

BACKGROUND: Defective or immature antibody responses to pathogens in children may explain the increased susceptibility to acute otitis media. However, there is no study in Korea patients whether a correlation exists between otitis media with effusion and the levels of serum immunoglobulins, IgG subclasses, IgA, IgM and IgE. METHODS: 45 children with otitis media with effusion more than 4 episodes in 12 months or 3 episodes in 6 months, 62 children with otitis media with effusion less than 3 episodes in 12 months and 102 children for control group took part in the study at the Department of Otorhinolaryngology of the KyungHee University from May 2004 to Feburary 2007. Serum immunoglobulin levels were determined by nephelometry. And then the relationship between otitis media with effusion and serum immunoglobulin level was evaluated. RESULTS: In otitis media prone group, serum IgG1, IgG2, IgG4, and IgA level was lower than those level of control group, it was significantly decreased (p0.05). CONCLUSION: Lower immunoglobulins in children with otitis media with effusion suggest a generalized decreased antibody responses. Lower levels of serum IgG1, IgG2, IgG4, and IgA may be related with chronicity or intractability of otitis media with effusion.