Hal J. Daniel

Microscopic Characteristics of Hacking Trauma

The purpose of this study was to determine if it is possible to associate machetes, axes, and cleavers with the microscopic parallel striations they leave on the cut surfaces of the bone. Hacking trauma was experimentally inflicted on pig bones using machetes, axes, and cleavers. Negative impressions of both the cut surfaces of the bone and the weapon blades were analyzed using scanning electron microscopy. The results of this investigation indicate that it is possible to correlate a class of hacking weapons to trauma inflicted on bone by these weapons.

Comparative Anatomy of Eustachian Tube and Middle Ear Cavity in Animal Models for Otitis Media

The comparative anatomy of the normal eustachian tube (ET) and normal middle ear cavity of three animal species (rat, gerbil, and chinchilla) is described relating to the usefulness of these animals as models for otitis media (OM). Routine histological and anatomical techniques and procedures were used. The gerbil and chinchilla, although of different sizes, are quite similar, having hypertrophied middle ear bullae, nearly vertical ET, and similar histology including seromucous glands draining directly into the ET. In contrast, the rat has a small bulla, a nearly horizontal ET, and a large concentration of goblet cells but few mucous glands in the ET. It appears that the chinchilla and the gerbil may serve as alternative models for OM research. Chinchillas and gerbils are relatively free of naturally occurring OM, while the rat has a high incidence of naturally occurring OM.

SOUNDS OF SEX AND DEATH IN THE SEA: BOTTLENOSE DOLPHIN WHISTLES SUPPRESS MATING CHORUSES OF SILVER PERCH

ABSTRACT Prey often exhibit avoidance behaviors when predators are present. We observed diminished loudness of mating choruses of male silver perch Bairdiella chrysoura in spawning areas when vocalizing bottlenose dolphins Tursiops truncatus, which hunt fish acoustically, were present. Experimental playback of bottlenose dolphin sounds revealed that male silver perch mating calls were reduced by an average of 9 dB. This “acoustical avoidance” behavior, demonstrated previously for interactions involving bats hunting insects and frogs, may also be a common phenomenon in acoustically mediated predator-prey interactions in the sea.

Otitis media in laboratory rats

Seventy-five of 260 Long-Evans rats (29%) were found to have middle ear infection, otitis media, when examined postmortem. The incidence of disease was found to increase with age of S and to be higher in females, as well as in animals subjected to stereotaxic brain lesions. It is suggested that several precautions be observed when using rats in auditory studies.

Nonsusceptibility to otitis media of the laboratory gerbil, Meriones unguiculatus

Mongolian gerbils housed with laboratory rats under conditions designed to maximize the transmission of otitis media were found at necropsy to be free of this middle ear disease, while the rats were found to have an 83% incidence.

Gender differences in laterality patterns for speaking and singing

This study examined behaviors reflecting cerebral organization of speaking and singing in normal college students. The investigation focused on whether differences existed in the laterality patterns of two singing tasks and one speaking task in males and females. Performance was measured on a verbal/manual time-sharing paradigm, coupling finger tapping with three vocal tasks (speaking, singing a rote song, singing up and down a diatonic five note scale). Females exhibited less variation than males in mean tapping rates and laterality scores across all three vocal tasks, thus indicating that gender most likely influences lateralization of vocal tasks. Bilateral integration was indicated for both males and females during singing up/down the aforementioned scale. These findings suggest differential involvement of both hemispheres in processing musical functions.

Aging and otitis media as sources of variance in the rat auditory brainstem response

Auditory brainstem response (ABR) latencies were examined in normal female Sprague-Dawley rats at 6 months of age and in 10-12 month old animals which tested positive for Mycoplasma pulmonis, a frequently implicated pathogen in otitis media. Significant differences in the peak latencies of Waves I, II and IIIn were found between the two age groups. A significant age by intensity interaction effect was also identified for Waves II and IIIn. Since the age-related effects observed in Wave I were similarly reflected in Waves II and IIIn, it was concluded that the group differences were due to alterations of the auditory periphery and not to changes in the central auditory system.

Response to Crowley

Our article ℌOtitis media in laboratory ratsℍ (Daniel, Means, Dressel, & Loesche, 1973) was published as a precautionary note to researchers using rats for auditory research. In our article, postmortem middle-ear explorations revealed that the incidence of otitis media increased from approximately 18% to 50% when rats maintained under normal clean conditions (NIH, 1968) reached the age of 6 months. Based upon this observation and others reported in the same paper, we made the following recommedations for auditory researchers: (l)rats should be examined either by radiological methods (Grice et al, 1955) or by postmortem middle ear exploration, (2) younger rats should be used, (3) male rats should be used, and (4) brain surgery should be avoided when possible.