To regulate ionic and fluid homeostasis, the colon relies upon a series of Na(+)-dependent transport proteins. Recent studies have identified a sodium/hydrogen exchanger (NHE) 4 (NHE4) protein in the gastrointestinal tract but to date there has been little description of its function. Additionally, we have previously shown that aldosterone can rapidly modulate Na(+)-dependent proton excretion via NHE proteins. In this study we examined the role of NHE4 in rat and human colonic crypts, determined the effect of aldosterone on NHE4 specifically, and explored the intracellular pathways leading to activation. Colonic samples were dissected from Sprague-Dawley rats. Human specimens were obtained from patients undergoing elective colon resections. Crypts were isolated using ethylenediaminetetraacetic acid and intracellular pH (pH(i)) changes were monitored using 2'-7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF). Crypts were exposed to 7 μM ethylisopropylamiloride or 400 μM amiloride, doses previously shown to inhibit NHE1 and NHE3 but allow NHE4 to remain active. Functional NHE4 activity was demonstrated in both rat and human colonic crypts. NHE4 activity was increased in the presence of 1 μM aldosterone. In the rat model, crypts were exposed to 100 μM 3-isobutyl-1-methylxanthine/1 μM forskolin and demonstrated a decrease in NHE4 activity with increased cAMP levels. No significant change in NHE4 activity was seen by increasing osmolarity. These results demonstrate functional NHE4 activity in the rat and human colon and an increase in activity by aldosterone. This novel exchanger is capable of modulating intracellular pH over a wide pH spectrum and may play an important role in maintaining cellular pH homeostasis.

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Shape, tip projection, and position can be controlled by the use of septal extension grafts (SEG). A retrospective cohort study of patients undergoing primary and secondary rhinoplasty was reviewed. The purpose of this study was to analyze maintenance of nasal length, dorsal length, and nasolabial angle postoperatively comparing different types of SEG using standardized photography and digital measurement. Two-hundred twenty-one patients undergoing rhinoplasty were included. There was a statistically significant change regarding the nasolabial angle during the time of follow-up decreasing from 97.53 to 95.30 degrees. No changes could be found in dorsal and nasal length. There was no significant difference among the techniques used to fixate the SEG. The nasolabial angle appeared to decrease from the position 2 weeks postoperatively without changes in the dorsal and nasal length. This means that the decrease in the nasolabial angle depends on the swelling effect and not on drooping of the tip confirming the reliability of SEG over time.

Breast deformity, in post-burn patients, is a common problem leading to lower self-esteem and reclusive behavior that impairs quality of life. The authors present the course of treatment of an 18-year-old immigrant girl who suffered second- to third-degree burns over approximately 20% of her total body surface area in her early childhood. The second- to third-degree burns were located on her right trunk and abdomen, as well as her right shoulder, neck, and right groin area. Since it was not offered in her home country, reconstructive surgery, including microsurgical breast reconstruction, was sought abroad. Due to the lack of available skin and soft tissue, a bilateral breast reconstruction with free transverse myocutaneous gracilis flaps was offered. This case illustrates one method of using microsurgery to address post-burn breast deformities in order to alleviate psychological suffering and improve quality of life.