W. Paul Biggers

Variation of Endocochlear Po2 and Cochlear Potentials by Breathing Carbon Dioxide

The effect of carbon dioxide on oxygen tension in the endolymph was determined by the micropolarographic technique. Different concentrations (5% and 10% CO2) and different exposure times (3, 5, and 20 minutes) were investigated. The highest levels of Po2 in the endolymph (101.7, 93.9 and 69.5 mm Hg) were accomplished by respiration of 10% CO2, 90% O2, for 20, 5, and 3 minutes consecutively. The lowest Po2 increase, 50.7 mm Hg was observed after breathing 5% CO2, 90% O2 for 20 minutes. Extreme hypercapnia caused an increase of endocochlear potentials (EP) in all groups. In the second group EP increased from +79.3 to +84.9 and in all groups they had returned to the pretreatment level after CO2 discontinuation. These results support the theory that carbonic anhydrase participates in the generation of EP. At the same time that EP increased, cochlear microphonics declined and opposite after the breathing mixture was discontinued. The results permit the conclusion that high levels of Po2 in endolymph is achievable even with short periods of respiration with high CO2 mixture, and suggest the role of carbonic anhydrase during EP generation.

A correlation of the effects of normoxia, hyperoxia and anoxia on PO2 of endolymph and cochlear potentials.

Change in PO2 in endolymph, endocochlear potentials and cochlear microphonics have been tested in normoxia, hyperoxia and anoxia on 24 guinea pigs. The polarographic method and construction of oxygen-sensitive microelectrodes is described in detail. The normal level of PO2 in endolymph vaires between 20 and 30 mm Hg. One-minute anoxia induced by breathing 100% N2 caused a decline in PO2, EP and CM, but during recovery only PO2 returned with over-correction to the preexposure level. Hyperoxia evoked by breathing 100% oxygen failed to increase the cochlear potentials and the PO2 in the endolymph. This suggests that vasoconstriction most likely occurs proximal to the capillaries bed of the stria vascularis.

Electronystagmography and audio potentials in space flight

Beginning with the fourth flight of the Space Transport System (STS‐4), objective measurements of inner ear function were conducted in near‐zero G conditions in earth orbit. The problem of space motion sickness (SMS) was approached much like any disequilibrium problem encountered clinically. However, objective testing techniques had built‐in limitations superimposed by the strict parameters inherent in each mission. An attempt was made to objectively characterize SMS, and to first ascertain whether the objective measurements indicated that this disorder was of peripheral or central origin. Electronystagmography and auditory brain stem response recordings were the primary investigative tools. One of the authors (W.E.T.) was a mission specialist on board the orbiter Challenger on the eighth shuttle mission (STS‐8) and had the opportunity to make direct and personal observations regarding SMS, an opportunity which has added immeasurably to our understanding of this disorder. Except for two abnormal ENG records, which remain to be explained, the remaining ENG records and all the ABR records made in the weightless environment of space were normal.Beginning with the fourth flight of the Space Transport System (STS-4), objective measurements of inner ear function were conducted in near-zero G conditions in earth orbit. The problem of space motion sickness (SMS) was approached much like any disequilibrium problem encountered clinically. However, objective testing techniques had built-in limitations superimposed by the strict parameters inherent in each mission. An attempt was made to objectively characterize SMS, and to first ascertain whether the objective measurements indicated that this disorder was of peripheral or central origin. Electronystagmography and auditory brain stem response recordings were the primary investigative tools. One of the authors (W.E.T.) was a mission specialist on board the orbiter Challenger on the eighth shuttle mission (STS-8) and had the opportunity to make direct and personal observations regarding SMS, an opportunity which has added immeasurably to our understanding of this disorder. Except for two abnormal ENG records, which remain to be explained, the remaining ENG records and all the ABR records made in the weightless environment of space were normal.

Frontal sinus trephination: A new technique for office procedure

A new office technique for frontal sinus trephination is described. The procedure is simple, expedient, and inexpensive. Our experience with 16 patients suggests that this procedure is reasonably safe and, in addition, avoids the often‐seen complications of supra‐trochlear nerve injury and persistent noticeable scar.

Changes in plasma proteins of mice during rejection of skin homografts and heterografts.

Conclusions Mice which have received homografts and heterografts respond by increasing the level of their alpha 2 globulins. A greater increase of alpha 2 globulins is observed following the application of second set grafts, and a decrease in alpha 2 globulins can be demonstrated following excision of foreign tissue grafts. Such findings suggest that the alpha 2 globulins are altered by foreign tissue antibody formation. That such antibodies are related to the specific destruction of foreign tissue implants, however, is conjectural. Summary. Following application of a single homograft or heterograft of full thickness skin, albumin, alpha 1, beta, and gamma globulin fractions of the plasma proteins of C3H mice remain unchanged as compared to changes following autografting while the alpha 2 fraction increases significantly. Repeated grafting resulted in higher alpha 2 levels than did a single graft. A return to normal of the alpha 2 fraction could be produced by excising the homograft or heterograft before necrosis occurred.

Human Papillomavirus: Its Significance in Tumor Margins

At the 92nd annual meeting of the American Academy of Otolaryngology–Head and Neck Surgery in Washington, DC, Abby E. Gross, MD, and coworkers, Albert Einstein Medical College, New York, NY, presented their investigation concerning the significance of human papillomavirus (HPV) in tumor margins in squamous cell carcinoma of the upper aerodigestive tract. Previous studies of tissue adjacent to benign lesions induced by the presence of HPV types 6 and 11 suggested viral involvement beyond the gross lesion with presence of HPV DNA. Verrucous carcinoma, an exophytic variant of squamous cell carcinoma, has been noted to contain the HPV DNA protein when examined, and to exhibit the histologic phenomenon of koilocytosis. Koilocytosis was defined as the cellular characteristic of an enlarged hyperchromatic nucleus with perinuclear halos. This has been considered by some pathologists as pathognomonic in squamous cell carcinoma of the uterine cervix. The authors reminded the audience that HPV, a

Comparison and Contrast of Two Multichannel Cochlear Implant Devices

Ian M. Windmill, PhD, Louisville, at the annual meeting of the American Academy of Otolaryngology–Head and Neck Surgery Foundation Inc in San Antonio, Tex, presented a detailed comparison of two multichannel cochlear implant systems employed at the University of Louisville. The devices compared were the Symbion four-channel device and the Nucleus 22-channel device. Dr Windmill and colleagues (Serge A. Martinez, MD, Michael B. Nolph, MD, and Barbara Eisenmenger, MS) pointed out that these systems differ in a number of important ways including engineering design, electrode count, surgical management, cosmetic appearance, and protocols. These major differences made direct comparison of the devices difficult, but the authors did an admirable job, with a very detailed analysis of postoperative results. It was pointed out that the receptive and perceptive results of studies on cochlear implants are not the only considerations when comparing the quality and efficacy of a cochlear implant system. Preimplant procedures,

A Comparison of Magnetic Resonance Imaging and Computed Tomographic Scanning and the Evaluation of the Anterior Skull Base

At the annual meeting of the American Academy of Otolaryngology–Head and Neck Surgery Foundation Inc in San Antonio, Tex, Paul A. Levine, MD, presented the experience of the University of Virginia regarding the evaluation of the anterior skull base utilizing magnetic resonance imaging (MRI) and high-resolution computed tomographic (CT) scanning. Dr Levine pointed out that economic considerations make it imperative that we delineate the clinical situations in which MRI is distinctly superior to high-resolution CT scanning to ensure the most cost-effective utilization of these diagnostic techniques. It was shown that recent articles asserted the superiority of MRI in head and neck imaging, along with the accepted fact that MRI provides improved imaging of the central nervous system. During the course of his discussion, Dr Levine stated that bony boundaries are more easily visualized on CT scans and that these studies are more readily available in most hospitals than are MRI