Mutational status of overexpressed p16 in head and neck cancer: evidence for germline mutation of p16/p14ARF.

Inactivation of the p16 tumor suppressor gene is a common phenomenon in squamous cell carcinoma of the head and neck (SCCHN). Less commonly described is the observation of p16 overexpression in SCCHN. Since overexpression of p16 is a potent predictor of outcome in other cancers, we were interested in determining the level of expression of p16 in our SCCHN specimens as a prerequisite to later prognostic studies. We were also interested in determining the mutational status of p16 in these tumors, in order to determine whether the combination of overexpression and gene alteration may predict a different clinical outcome from overexpression alone. A total of 84 specimens of SCCHN were selected for study. These specimens were obtained from all major sites within the oral cavity, oropharynx, pharynx and larynx. The level of expression of p16 in SCCHN specimens was measured by semi-quantitative RT-PCR. In 35 cases, RNA was also isolated from matched normal tissue obtained from a negative tumor margin. In the other 49 cases, the expression level was compared with the level of expression measured in pooled normal RNA obtained from 10 specimens of normal epithelial tissue. Overexpression of p16 was documented when the level of expression in the tumor specimen was 2-fold or greater above the level of expression found in normal tissue. A total of 46 specimens demonstrated overexpression of p16 (55%). All specimens demonstrating overexpression were then subject to sequence analysis. Thirty specimens (65%) showed p16-specific gene alterations, ranging from intragenic deletions to single point mutations, and 15 of these cases concomitantly affect p14ARF. A single specimen demonstrated a silent point mutation within the p16 reading frame. This mutation produces a stop codon at residue 85 in the context of the p14ARF reading frame, predicting premature termination of p14ARF within a previously determined nucleolar localization signal. This observation suggests that in some cases at least, p14ARF may be a selective target for alteration, independently of p16. Analysis of a normal tissue specimen obtained from a negative tumor margin, and a blood sample obtained approximately five years after surgery indicate that this p14ARF-specific alteration may represent a germline mutation.

Importance of chin evaluation and treatment to optimizing neck rejuvenation surgery.

The chin is the keystone linking the aesthetics of the face and neck but is often neglected in the analysis. Procedures related to the chin play an important role in defining neck anatomy. Alloplastic implants can provide the illusion of a longer jaw line in a patient with retrogenia. Even greater anatomic changes to the neck result when a sliding genioplasty is performed. This effect is primarily due to the digastric attachments from the mentum and mastoid. Advancing the mentum may have a more direct effect of elevating the position of the hyoid, which sharpens the angle between the jaw and neck. Finally, the diagnosis of a witch's chin is also discussed for the patients who present for aging neck surgery.

Reconstruction of large nasal defects.

Large nasal defects resulting from trauma or oncologic resection are a difficult reconstructive challenge, requiring special structural and aesthetic considerations. This article reviews reconstructive options by anatomic site and discusses techniques that address more complex defects, such as those involving multiple aesthetic units.

Bilateral lateral rhinotomy incisions for medial maxillectomies in the management of pediatric invasive fungal sinusitis.

OBJECTIVE: To determine if simultaneous, bilateral lateral rhinotomies for medial maxillectomies would result in central skin or bone loss in pediatric patients with invasive fungal disease. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care children's hospital. PATIENTS: Three children underwent surgery between April 1996 and June 1998. Ages at treatment ranged from 11 to 14 years. All had bilateral, biopsy-proven invasive fungal disease of the lateral walls of the nose. All were undergoing chemotherapy for acute lymphocytic leukemia (ALL) or acute myelocytic leukemia (AML). INTERVENTION: Bilateral lateral rhinotomies for medial maxillectomy. Two of 3 also had simultaneous total septectomy. MAIN OUTCOME MEASURE: Skin survival and patient survival. RESULTS: All three patients had bilateral simultaneous medial maxillectomy for invasive fungal disease in the presence of profound pancytopenia secondary to treatment of leukemia. One patient had minor nasal edema postoperatively, but none showed any loss of the central nasal skin or facial skeleton. All patients survived the invasive fungal disease with follow-up of at least 24 months. All patients underwent multiple debridements after the original surgery, and 3 of 6 eyes had permanent epiphora requiring dacryocystorhinostomies. CONCLUSIONS: Bilateral simultaneous lateral rhinotomies are safe in children and did not result in any central skin loss. Aggressive bilateral surgery for invasive fungal disease is compatible with a good esthetic outcome and long-term survival.

p16 mutation frequency and clinical correlation in head and neck cancer.

The tumor suppressor gene p16, when altered, has been shown to play a role in oncogenesis in many different tumor types including head and neck cancer. The goal of this study was to analyse alterations to p16 in squamous cell carcinoma (SCC) of the head and neck and to correlate these with clinical outcome. RNA was isolated from 26 SCC head and neck tumors and from 24 matched controls. A reverse transcription polymerase chain reaction was utilized to generate p16 cDNA, which was sequenced and analysed for alterations. In the 26 patient group 58% of the tumors had a p16 alteration, which were characterized by: 8 deletions, 1 insertion/deletion, 4 point mutations and 2 with no p16 expression. In 24 matched normal tissue samples there were no p16 alterations. Those patients with p16 alterations appear to have survival rates comparable to those without p16 alterations, although patients with p16 alterations appear to have more recurrences.

Growth factors during endotoxin-induced otitis media.

The presence of growth factors in the middle ear fluid was examined during lipopolysaccharide-induced otitis media (OM) in the chinchilla. There was a progressive significant increase in the proliferative activity detected in the LPS-free MEF by five days in culture. We conclude that lps indirectly mediates hyperproliferative changes in the middle ear during OM by inducing growth factors.

A monoclonal antibody identifies vimentin filaments in Sertoli cells and in a subset of epithelial cells in the rat epididymis, urinary bladder, and prostate.

PURPOSE: We describe a monoclonal antibody (Mab B2) against vimentin filaments in rat Sertoli cells and in a subset of epithelial cells in the rat epididymis, prostate and urinary bladder. MATERIALS AND METHODS: The immunoreactivity of Mab B2 was examined on cryostat sections and immunoblots and compared with the reactivity of a previously characterized monoclonal antibody against vimentin. RESULTS: While both antibodies recognized vimentin in Sertoli cells, only Mab B2 recognized vimentin in urogenital tract epithelia. CONCLUSIONS: Vimentin is expressed in the urogenital tract, and differential reactivities of antibodies may be responsible for conflicting results reported elsewhere for vimentin expression.

Germ cell binding to rat Sertoli cells in vitro.

The interaction between male germ cells and Sertoli cells was studied in vitro by co-incubation experiments using isolated rat germ cells and primary cultures of Sertoli cells made germ cell-free by the differential sensitivity of germ cells to hypotonic shock. The germ cell/Sertoli cell interaction was examined morphologically with phase-contrast and scanning electron microscopy and then quantified by measuring radioactivity bound to Sertoli cell cultures after co-incubation with added [3H]leucine-labeled germ cells. Germ cell binding to Sertoli cell cultures was the result of specific adhesion between these two cell types, and several features of this specific adhesion were observed. First, germ cells adhered to Sertoli cell cultures under conditions during which spleen cells and red blood cells did not. Second, germ cells had a greater affinity for Sertoli cell cultures than they had for cultures of testicular peritubular cells or cerebellar astrocytes. Third, germ cells fixed with paraformaldehyde adhered to live Sertoli cultures while similarly fixed spleen cells adhered less tightly. Neither live nor paraformaldehyde-fixed germ cells adhered to fixed Sertoli cell cultures. Fourth, germ cell binding to Sertoli cell cultures was not immediate but increased steadily and approached a maximum at 4 h of co-incubation. Saturation of germ cell binding to Sertoli cell cultures occurred when more than 4200 germ cells were added per mm2 of Sertoli cell culture surface. Finally, germ cell binding to Sertoli cell cultures was eliminated when co-incubation was performed on ice. Based on these observations, we concluded that germ cell adhesion to Sertoli cells was specific, temperature-dependent, and required a viable Sertoli cell but not necessarily a viable germ cell. These results have important implications for understanding the complex interaction between Sertoli cells and germ cells within the seminiferous tubule and in the design of future experiments probing details of this interaction.