No abstract

No abstract

Spiral ganglion cells were counted in the right cochleae of 16 patients with normal audiograms and without a history of hearing deficit or other auditory symptoms. Total counts ranged from 29 802 to 38 352, with a mean of 33 623. There was no relationship between total counts and patient age or between total counts and length of either the cochlea or the spiral ganglion.

A simplified radioenzymatic assay for chloramphenicol was developed by eliminating the need for cumbersome extraction procedures. After the acetylation of chloramphenicol with [14C]acetyl coenzyme A in the presence of chloramphenicol acetyltransferase, the reaction mixture was added to a toluenebased scintillation fluid. Since "4C-acetylated chloramphenicol is more soluble than [14C]acetyl coenzyme A in toluene, the radioactive product could be counted directly. The rapidity of this assay, as well as its accuracy, precision, and specificity, makes it particularly suitable for clinical use. In contrast to previous reports of enzymatic assays for chloramphenciol, we have found that results of the assay of standards prepared in serum were up to 25% higher than those of standards prepared in saline, cerebrospinal fluid, or urine.Renewed interest in the clinical use of chloramphenicol is based on its value in treating: (i) anaerobic infections, especially those involving penicillin-resistant Bacteroides fragilis; (ii) meningitis in which ampicillin-resistant Haemophilus influenzae is suspected or proven (1); and (iii) ventriculitis in which penetration of aminoglycosides into the cerebrospinal fluid (CSF) may be inadequate (4).We have developed a simplified radioenzymatic assay for chloramphenicol. Like that previously described (2, 5), it is based on the specific acetylation of chloramphenicol with [14C]acetyl coenzyme A by chloramphenicol acetyltransferase. Unlike the previously described enzymatic assays, our method allows the direct extraction of 14C-acetylated chloramphenicol into scintillation fluid and circumvents more cumbersome extraction methods. In contrast to the previous reports, we find a substantial difference between the acetylations of chloramphenicol standards in serum and in saline, CSF, or urine.

No abstract