Merkel cell carcinoma: an overview and case report.

Merkel cell carcinoma is an extremely rare neoplasm with a high rate of recurrence and metastasis. The lesions predominantly arise on sun-exposed areas of skin in whites between the sixth and seventh decades of life. Within the head and neck region, the cheeks and eyelids are the most common sites. This article outlines the etiology, pathogenesis, and treatment of this rare but highly aggressive tumor.

Congenital nasal pyriform aperture stenosis.

Congenital nasal pyriform aperture stenosis is a rare cause of pediatric nasal airway obstruction. As infants are obligate nasal breathers, nasal obstruction and even severe nasal congestion can lead to apnea and respiratory distress. Congenital nasal pyriform aperture stenosis was first described by Brown et al in 1989. The narrowing of the nasal pyriform aperture is thought to be due to bony overgrowth of the nasal process of the maxilla during fetal development. Because of the association this anomaly has with other midline defects, such as holoprosencephaly, it is important to recognize it and pursue a thorough workup. We present a case of a patient with pyriform aperture stenosis and solitary central megaincisor. This patient initially presented to our clinic with a history of nasal airway obstruction, poor feeding, and failure to thrive.

The otologic manifestations of barotrauma.

Barotrauma is defined as an injury due to pressure differences between atmospheric and intratympanic pressures. Human beings are well suited to operate within an environment involving small alterations in atmospheric pressure. Man's persistence in operating outside this environment leads to exposure to large pressure differentials with resulting trauma. External, middle, and inner ear structures can all be injured due to alterations in pressure. The increase in popularity of sport diving and aviation travel has led to an increase in the number of otologic injuries caused by barotrauma. The physics, pathophysiology, symptoms, and treatment of barotrauma are presented.

Effects of androgen deprivation on prostate alpha 1-adrenergic receptors.

OBJECTIVES: Benign prostatic hyperplasia (BPH), the most common benign tumor in men, consists of two components-static (enlargement regulated by androgens) and dynamic (smooth muscle contraction through alpha 1-adrenergic receptors [alpha 1-ARs]). Because medical therapy of BPH involves tissue androgen deprivation, we studied the influence of androgen deprivation and replacement on regulation of rat ventral prostate alpha 1-ARs. METHODS: Prostate weight, alpha 1-AR density, autoradiographic images, histologic features, and cell-specific protein were examined before and after castration and androgen replacement. RESULTS: Castration decreases ventral prostate wet weight, a process reversed by testosterone administration. In contrast, there is an apparent increase in alpha 1-AR density (29 +/- 4 versus 65 +/- 6 fmol/mg total protein, mean +/- SEM) after castration, returning to baseline with testosterone replacement; alpha 1-AR density remains constant in control liver membranes. Alpha 1-ARs predominate in stroma throughout androgen deprivation therapy. Epithelially derived cells decrease (83% to 67%) after castration, resulting in a relative doubling in stroma (17% to 33%); the protein content of epithelial and stromal cells remains identical. Therefore, prostate-specific increases in alpha 1-ARs appear to result from relative increases in the ratio of smooth muscle to epithelium after castration rather than from direct upregulation of alpha 1-AR protein. CONCLUSIONS: Because alpha 1-AR density does not decrease with androgen deprivation, these studies suggest that alpha 1-AR antagonists remain an important component in BPH therapy, even when 5-alpha-reductase inhibitors are utilized.