Faculty Bibliography

A simple and rapid method for the determination of human T lymphocyte subclasses in buffy coat preparations or whole blood is described. This technique uses flow cytometry to distinguish lymphocytes from other leukocytes on the basis of their light-scattering properties. Lymnphocyte subclasses were enumerated by cellular immunofluorescence; the immunofluorescent signals were produced by monoclonal antibodies to surface differentiation antigens on T cells. Conventional techniques of enumerating T lymphocyte subclasses entail time-consuming (up to 2 days) density gradient and E rosette enrichement, and require at least 20 ml of blood. The method described here uses as little as 50 microliters of whole blood for each antibody tested and produces results within in 2 hr.

Between 1969 and 1978 7,000 patients underwent cardiopulmonary bypass at Bellevue and University Hospitals. In seven of these patients, sudden loss of hearing in one ear developed immediately after the operation. Four of the seven patients showed improvement in hearing after the initial loss, although in no case did the hearing return completely to normal. None of the patients had vertigo but two were listless postoperatively. Two of the operations were for congenital heart disease; the remainder were coronary artery bypass procedures. All of the affected patients were male. There was no predilection as to which ear was affected. The most likely cause is particulate emboli generated by cardiopulmonary bypass. Other possible sources of emboli include air, antifoam, fat, and particulate matter from calcified valves and the aorta. Improvement in the kind of pump and the addition of various filters in the period between 1969 and 1978 did not eliminate unilateral hearing loss. The relationship between cerebral emboli and decreased consciousness after operations is also discussed

Anatomical, physiological and behavioral data indicate that the auditory system matures from the periphery centrally, ie, centripetally. There is now information which shows that the developing auditory system can be modified by anatomical changes which have their greatest effect during early development. Anatomical, physiological and behavioral changes can also be brought about by the quality of the auditory stimuli which th auditory system experiences. Evidence for the plasticity of the developing auditory system has come from studies of a number of different species. The plasticity of the auditory system is of theoretical and clinical significance.

The harmonic components in hoarse voice were separated from the noise components by using a small laboratory computer. The ratio of harmonics to noise or S/N ratio, was calculated and compared with the auditory impression for 58 subjects. The calculated results showed a definite correlation to the auditory impression, and it is suggested that this would be a useful method for the quantitative evaluation of hoarseness.

1. Isolated, unstimulated abdominal ventral nerve cords of Limulus display patterns of motor output characteristic of rhythmic gill ventilation and of gill cleaning (Fig. 2). 2. The motor output may occur as long-term patterns of alternate gill cleaning and ventilation (Fig. 3), or alternate gill cleaning and tonic activity (Fig. 4). 3. Two patterns of gill cleaning motor output, apparently corresponding to the left-leading and right-leading patterns observed in intact animals, persist in the isolated ventral cord (Fig. 4). These two patterns occur with the same rough alternation as in intact animals. 4. Thus all the patterns of gill-plate movement in intact animals, except those involving swimming, have underlying motor programs that are expressed in isolated nerve cords in the absence of stimulation or of sensory feedback. These findings extend the concept of central pattern generators to include complex and long-duration patterns of stereotyped behavior such as those underlying the movements of the Limulus abdominal appendages

Thresholds of the auditory nerve compound action potential (CAP) responses to filtered clicks from 0.5 to 40 kHz, defining a CAP frequency threshold curve, have been determined in the same guinea pigs: (1) in acute conditions, the animal still anesthetized at the end of the operation for permanent implantation of a round-window electrode, and (2) several days later in the implanted awake and unrestrained animal. The results show higher CAP thresholds for high frequencies in acute conditions as compared to chronic recordings. This difference appears above about 12.5 kHz and increases progressively to around 40 dB at 40 kHz. Similar effects, although somewhat less pronounced, were observed during anesthesia alone in already implanted guinea pigs. Thes observations could explain the discrepancies which appear between electrophysiological thresholds, acutely recorded either from single fibers or whole-nerve responses, and behavioral audiograms. Moreover, in the accurate evaluation of the cochlea, slight impairments may be masked by this phenomenon as illustrated in guinea pigs treated with low doses of ototoxic antibiotic.

Disenchantment with the limitations, and in some cases the morbidity, of currently used radiologic techniques for the demonstration or exclusion of small acoustic neuromas prompted development of an examination using small amounts of intrathecal air and computed tomography (CT). A prospective study was designed to evaluate air CT cisternography/canalography, wherein patients with the clinical symptoms of acoustic neuroma but with negative enhanced CT, were evaluated by metrizamide CT cisternography followed by air CT cisternography/canalography. Pantopaque cisternography was then performed as a control procedure. Four patients had surgically proven tumors. In 13 others, accumulated evidence indicated no tumors were present. Results suggest that air-CT cisternography is superior to all other diagnostic methods in defining small acoustic neuromas, and may exclude an intracanalicular lesion without the potential hazards of Pantopaque cisternography or high concentration metrizamide tomocisternography. With air-CT cisternography, there were no errors in this series