The human Sertoli cell population was characterized in 14 men by histometric analysis and by direct counts of nuclei in testicular homogenates. Testes obtained at autopsy were perfused with glutaraldehyde and embedded in Epon. Nucleolar and nuclear volumes were determined by the formula of a sphere given the diameter of the nucleoli or average diameter of nuclei measured at the height and width. Nuclear volume was also estimated by adding volumes of nuclear profiles in 0.5-micron serial sections. Sertoli cell number/g was calculated by the product of the percentage nucleoli or nuclei in the parenchyma, parenchymal volume, and histologic correction factor divided by the volume of a single nucleolus or nucleus. Also, Sertoli cell nuclei were counted directly in homogenates of fixed parenchyma. Number of Sertoli cells/g was similar (P greater than 0.05) whether determined by serial sections or in homogenates, but the estimate based on the nucleolar method was higher (P less than 0.01) and the nuclear measurement method was lower (P less than 0.01) than that for serial sections. A group of 37 men aged 20 to 48 yr had significantly (P less than 0.01) more Sertoli cells than did 34 men aged 50 to 85 yr. It is concluded that: 1) the homogenate method is valid for quantification of the Sertoli cell population, 2) Sertoli cells are evenly distributed in different regions of the testis, 3) the average human Sertoli cell supports relatively few germ cells, 4) the human Sertoli cell population declines with age, and 5) there is a significant relationship between sperm production rates and number of Sertoli cells.

Despite new technology, diagnosis of the dizzy patient remains a problem. While computer analysis permits objective, quantitative assessment of vestibular function, the large variability in normal subjects makes diagnosis difficult-particularly in minor dysfunction. This study assesses the diagnostic capabilities of the three modalities of vestibular testing: caloric irrigation, sinusoidal rotation, and posturography. METHODS AND MATERIALSSeventy consecutive patients with subjective reports of vertigo underwent extensive vestibular evaluation. The group included 23 men and 47 women, with an average age of 46.7 years. Final diagnosis was based on clinical impressions and interpretation of diagnostic tests.Bithermal caloric stimulation was performed using the Fitzgerald-Hallpike technique, with responses considered to be abnormal when asymmetry exceeded 20 percent. Rotational testing included multiple frequency sinusoidal rotations in the dark about a vertical axis. Methods of stimulation, eye movement recordings, and data analysis have been published previously. ' Posturographic testing was performed using the commercially available computerized dynamic posturography platform. A complete description of this test is available in the literature.' Results of the tests were compared to normative data collected in the laboratory or supplied by the manufacturer in the case of posturography. RESULTSIn this group of patients, diagnoses included: endolymphatic hydrops ( 12); acoustic neuroma (6); unilateral peripheral dysfunction (1 5); bilateral peripheral dysfunction (5); nonlocalizing vestibular dysfunction

No abstract

Bithermal caloric testing was carried out in 57 normal subjects and 374 patients presenting with subjective complaints of vertigo over a 4-year period from December 1984 to December 1988. Responses were quantitatively assessed using a DEC PDP 11/73 laboratory minicomputer. Patients were classified as normal and abnormal according to caloric responses based on standard methods of calculating unilateral hypoexcitability and directional preponderance using the maximum slow component velocity. Results obtained from the slow component velocity for unilateral hypoexcitability and directional preponderance were compared to the same values obtained from the overall positional envelope calculated by an integration of the slow component velocity vs. time curve. Although duration of nystagmus varies extensively in normal subjects and has not proven clinically useful in identifying abnormalities, the integral of response amplitude over time gives a more complete description of the vestibular response. However, when compared to the maximum slow component velocity in abnormal patients, the positional envelope identified only 94 of the total 119 abnormalities (79%). Therefore, maximum slow component velocity is the more sensitive response parameter in identifying vestibular pathology.