We have used the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques to design two genetic markers for blue mussels in the Mytilus edulis species complex. Both of these markers target the gene encoding the mussel polyphenolic adhesive protein. The first marker, Glu-5', is highly differentiated among and can be used to identify the three blue mussel species, M edulis, M galloprovincialis and M trossulus. The second marker, Glu-3', can identify M edulis and M galloprovincialis. Using these markers we have demonstrated that hybrid mussels from Whitsand Bay, UK carry alleles for this gene that are the products of intragenic recombination. The high frequency (10 per cent) of these recombinant alleles within the hybrid population suggests that recombination is fairly frequent within this gene or that hybridization between M. edulis and M. galloprovincialis is substantial and has been occurring over considerable evolutionary time. The two novel genetic markers, Glu-5' and Glu-3' will be invaluable in additional studies regarding the importance of hybrization among blue mussels.

A small number of patients develop otolaryngological complications, most commonly, frontal mucoceles, following frontal craniotomy. A high level of suspicion and long-term surveillance are needed to monitor for their occurrence. Endoscopic marsupialization may provide an effective, safe means for management.

Black males who present to the otolaryngologist-head and neck surgeon for evaluation of sleep-disordered breathing may be at increased risk of severe OSA.

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Scientific Posters P255 that LAUP for the treatment of snoring is time limited, requiring further treatment in some patients. Methods: LAUP was performed in the outpatient setting using the CO 2 laser and local anesthesia in all patients. A 5year follow-up sleep questionnaire was completed by two thirds of patients with a recurrence of snoring. Results: Results of our study are based on a 5-year experience from June 1993 to June 1998. A total of 409 patients were treated with LAUP for snoring and obstructive sleep apnea. A recurrence of snoring occurred in 15 (3.7%) patients. Conclusion: LAUP is a relatively new procedure for the treatment of snoring and obstructive sleep apnea with no longterm follow-up reported in the literature. Conclusions from this 5-year experience with 409 patients are that 3.7% of patients treated with LAUP had recurrence of snoring and that there are no patient characteristics that predict the recurrence of snoring.