ABSTRACT
OBJECTIVE: Obtain measurements of globe projection, intercanthal distance (ICD), interpupillary distance (IPD), palpebral fissure width (PFW), and palpebral fissure height (PFH) in a population of presumably normal white and black adults to determine if any significant differences exist between these groups. STUDY DESIGN: Prospective direct measurement of cohorts regarding orbital and globe measurements in a tertiary medical center. METHODS: Measurements of globe projection, ICD, IPD, PFW, and PFH were taken in 61 black adults and directly compared with measures taken from 65 white adults in an outpatient setting. Mean values and ranges were calculated and compared between races and sexes using an unpaired t test. RESULTS: A significant difference was found between races for globe projection, with black males demonstrating a mean projection of 18.23+/-2.26 mm as compared with 17+/-2.65 mm for white males (P < .025). Black females demonstrated a mean projection of 17.27+/-1.44 mm as compared with 15.98+/-2.22 mm for white females (P < .01). Similar differences were seen for measures of IPD and PFW, with greater mean values for black as compared with white adults. No racial differences existed for ICD or PFH. CONCLUSIONS: These findings suggest that racial differences exist for certain measures of globe and orbital position, i.e., projection, IPD, and PFW. Racial background should be considered when evaluating orbital anatomy.
Subject(s)
Black People , Eye/anatomy & histology , Orbit/anatomy & histology , White People , Adult , Anthropometry , Female , Humans , Male , Prospective Studies , Reference ValuesABSTRACT
Expression of calcium/calmodulin-activated adenylyl cyclase type I (ACI) mRNA has been determined in the cochlea and in an organ-of-Corti subdissected tissue fraction by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Amplification products of predicted size were obtained from the mouse cochlea and rat organ of Corti with nucleotide sequences corresponding to respective ACI brain transcripts. In addition, ACI template was detected in a rat inner hair cell cDNA library by PCR. Immunoreactivity to ACI has been localized within the organ of Corti to the inner hair cell, with diaminobenzidine staining found in both the cell body and in the stereocilia. Evidence, thus, has been obtained that both ACI transcript and protein are expressed in the inner hair cell, the primary mechanosensory receptor cell of the cochlea. We hypothesize that ACI is activated by calcium influx through a calcium/calmodulin interaction and that this adenytyl cyclase isoform may have a role in modulation of receptoneural afferent transmission and/or mechanosensory transduction in the cochlea.
Subject(s)
Adenylyl Cyclases/biosynthesis , Hair Cells, Auditory, Inner/enzymology , Transcription, Genetic , Animals , Base Sequence , DNA Primers , DNA, Complementary , Gene Library , Mice , Mice, Inbred CBA , Molecular Sequence Data , Organ of Corti/enzymology , Polymerase Chain Reaction , RNA, Messenger/biosynthesis , Rats , Rats, Inbred ACIABSTRACT
The present study was designed to catalogue and compare nicotinic receptor subunit messages in the mammalian cochlea. Fourteen nicotinic acetylcholine receptor subunit messages were examined by polymerase chain reaction (PCR) analysis and nucleotide sequencing. Total RNA was extracted from the auditory organs of 14- to 18-day-old CBAJ mice, and mRNA was purified using oligo-dT cellulose. After reverse transcription, resulting cDNA was amplified by PCR with the use of primers specific for the nucleotide sequences representing the following nicotinic receptor subunits: muscle types alpha 1, beta 1, gamma, delta and epsilon and neuronal types alpha 2,3,4,5,6,7 and beta 2,3,4. cDNA from cochlear tissue corresponding to the muscle-type receptor subunit beta 1 and to neuronal-type receptor subunits alpha 2,4,5,6 and beta 2,3 was amplified, whereas cDNA for muscle types alpha 1, gamma, delta and epsilon and neuronal types alpha 3,7 and beta 4 was not. All PCR products were homologous in nucleotide sequence to the corresponding reference cDNAs from which the primers were designed. The current results indicate that nicotinic acetylcholine receptor (nAChR) subunits that are similar or identical to the stated muscle and neuronal types are expressed in the murine cochlea. The presence of messages corresponding to the muscle-type beta 1 and neuronal-type nAChR subunits may be correlated with the atypical cholinergic response of cochlear hair cells to agonists and antagonists.
Subject(s)
Cochlea/chemistry , Receptors, Nicotinic/classification , Receptors, Nicotinic/genetics , Animals , Base Sequence , DNA, Complementary/chemistry , Electrophoresis, Agar Gel , Mice , Mice, Inbred CBA , Molecular Sequence Data , Polymerase Chain ReactionABSTRACT
Effects of pulse width on discrimination of simultaneous changes in frequency and level of electrical pulse trains were studied in a monkey subject with a cochlear implant. At test-stimulus levels where performance was minimum, frequency difference limens were larger for longer-duration pulses than that for shorter-duration pulses. Several factors may have contributed to these differences.
