Comparison of the incidence of cholesteatoma surgery before and after using ventilation tubes for secretory otitis media.

Inserting ventilation tubes has become, probably, the most common surgical operation performed on children in the free world. In our study, we attempted to examine whether the widely used procedure of inserting ventilation tubes in children with secretory otitis media is indeed justified in the long term. For this purpose, we have studied the influence of the procedure on the formation of cholesteatoma by comparing the incidence of cholesteatoma surgery before and after using ventilation tubes in our department. The data were divided into two periods. The first period included the number of operations in the 10 years (1961-1970) before ventilation tubes were used as a routine treatment for secretory otitis media in our department. The second period included the number of operations in the last 10 years (1989-1998) following the usage of ventilation tubes over 30 years. We found that the number of cholesteatoma operations has decreased, from 413 operations in the 10 years before ventilation tubes were used to 228 operations over the last 10 years. The number of operations per 10000 of the entire population has decreased from 20 operations to 6.6 operations after using ventilation tubes (P=0.0000001). We have shown that the incidence of surgery for cholesteatoma has been declining. Having analyzed the options that might cause this decline, we believe that using ventilation tubes in secretory otitis media might help to reduce the incidence of cholesteatoma surgery in the long term.

The antiviral activity exerted by vaccinia virus on the growth of herpes simplex virus in BS-C-1 cells.

The growth of herpes simplex virus type 2 (HSV-2) in BS-C-1 cells, was inhibited following super-infection with vaccinia virus. This inhibition was efficiently induced by both the intracellular mature virus (IMV) form of vaccinia virus and the extracellular enveloped virus (EEV), containing an additional external viral membrane. Treatment of vaccinia IMV with the detergents NP-40, Brij-58 or n-octyl-alpha-D-glucopyranoside, abolished its ability to inhibit the growth of HSV-2. Ultraviolet irradiation of vaccinia virus, that completely inactivated the infectivity of the virus, resulted in partial loss of the capability to inhibit the growth of HSV-2: 16-fold more irradiated virus was needed for the inhibition. Electron microscopy showed that the irradiated vaccinia virus adsorbed and penetrated into the HSV-infected cells but remained morphologically intact within the cells for at least 22 h. When the steps in the growth of HSV affected by the irradiated vaccinia virus were followed, it was found that while the synthesis of HSV DNA was partially decreased, the synthesis of HSV proteins was very strongly inhibited and virus particles were not formed.

Co-infection of acyclovir-resistant and acyclovir-sensitive herpes simplex type 2 virus strains in BS-C-1 cells.

Co-infection of BS-C-1 cells by the herpes simplex virus type 2 (HSV-2) Curtis strain with its acyclovir (ACV)-resistant mutant (HSV-2-ACV(R)), resulted in a severalfold increase in virus yield, as compared to a single infection. On the other hand, when two viruses (G strain and HSV-2-ACV(R)) belonging to different strains of HSV-2 were involved, their growth was significantly inhibited; the decrease in the titer of the second virus to infect the cells was greater when its infection took place at later times following infection by the first. This inhibition was not due to the shut-off of host cell protein synthesis caused by the first virus, since an HSV-2 mutant which is unable to inhibit the protein synthesis of the host cell was still capable of efficiently inhibiting the growth of the superinfecting virus.

Safety of topical ear drops containing ototoxic antibiotics.

OBJECTIVE: Topical application of ear drops containing ototoxic antibiotics is commonly used for treatment of middle ear diseases. Because of their ototoxic potential, we evaluated the safety of these ear drops in clinical use. METHODS: The study included 446 children who underwent myringotomy and the insertion of tympanostomy tubes. Three hundred and fifty-eight received preventive treatment after the operation with polymyxin B-neomycin-dexamethasone ear drops for 2 weeks; 88 did not receive any ear drops. Audiometric tests were performed before the operation and up to 3 months following it. RESULTS: All 446 children had a normal sensorineural hearing threshold before and after the operation. There was no sensorineural hearing loss in the group that was treated with ear drops. CONCLUSIONS: Our experience leads us to believe that topical ear drops containing ototoxic antibiotics are clinically safe to use for a short period of time.