Biomedical subjects

M S Marion

Publications and source records attributed to M S Marion.

18 recordsLinked to original sources

PubMed1991

Tinnitus.

Tinnitus, a common complaint, reportedly affects more than 37 million Americans. Most often, it is associated with a sensorineural hearing loss in the high-frequency range. Tinnitus, however, is a symptom and not a disease. Complacency about this symptom complex may cause physicians to overlook a severe underlying pathologic process. Patients with unilateral tinnitus, pulsatile tinnitus, fluctuating tinnitus, or tinnitus associated with vertigo should undergo thorough assessment, including elicitation of a complete history, physical examination, and audiologic analysis. In many instances, treatment is effective. Masking of tinnitus, medical therapy, and biofeedback and counseling are some measures that have been used in the management of tinnitus.

Biofeedback, Psychology↗

PubMed1991

Labyrinthitis ossificans: histopathologic consideration for cochlear implantation.

Labyrinthitis ossificans may be a hindrance to cochlear implantation by making electrode insertion difficult. We performed a histopathologic study of 24 temporal bones with labyrinthitis ossificans from multiple causes. The organ of Corti was graphically reconstructed and the degree of obstruction was estimated for each millimeter of the cochlea. Correlations were calculated between the degree of new bone formation and the cause, patient's age and sex, and time from the original temporal bone insult. Our results demonstrate that complete cochlear ossification is rare. The scala tympani in the basal turn of the cochlea is the most frequent area of ossification, regardless of the cause of the labyrinthitis ossificans. Meningogenic labyrinthitis, usually a childhood disease, was associated with the greatest amount of ossification. When ossification resulted from tympanogenic labyrinthitis, the scala tympani was completely ossified near the round window niche in all temporal bones. Neo-ossification of the basal turn associated with otosclerosis was limited to the proximal 6 mm of the scala tympani in all cases. Three temporal bones had a patent round window niche and basal turn, but significant apical and middle-turn ossification. Peripheral sensorineural elements were severely degenerated in the region of the ossification in all specimens, and spiral ganglion cell counts were decreased.

Adolescent↗

PubMed1991

Ganglion cell populations in labyrinthitis ossificans.

Ossification of the perilymphatic spaces of the inner ear is frequently found in patients with profound deafness who may be candidates for cochlear implantation. The ossification may be a hindrance in electrode insertion and has previously been considered a relative contraindication to implantation. The quantity of peripheral auditory elements remaining in a series of patients with labyrinthitis ossificans has not been reviewed. We performed a histopathologic study of 16 temporal bones with partial cochlear ossification of multiple etiologies. The organ of Corti and spiral ganglion were graphically reconstructed. The degree of obstruction was estimated for each millimeter of the scala tympani and scala vestibuli. A quantitative evaluation of the sensorineural elements of the inner ear (spiral ganglion cells, inner and outer hair cells, and peripheral auditory axons) was performed. The results were compared with 16 control patients with normal hearing and no evidence of cochlear ossification. Our results show that the greatest amount of damage is found in the organ of Corti with preservation of a significant number of spiral ganglion cells in most cases. A wide range of ganglion cells (6,310 to 28,196) was found in patients with labyrinthitis ossificans with the mean number of ganglion cells being 17,152. A profound sensorineural hearing loss was noted in all patients except one. Meningogenic labyrinthitis and otosclerosis were associated with the greatest loss of ganglion cells. The location of ossification could be correlated with the region showing loss of the organ of Corti. In the majority of patients, the location of ossification and fibrosis could not be correlated with the region of the spiral ganglion showing loss of ganglion cells. The implications of these findings for cochlear implantation is discussed.

Adolescent↗

PubMed1990

Histopathologic evaluation of adipose autografts in a rabbit ear model.

Injection of autologous adipose tissue removed via liposuction has been used clinically for facial contouring, the aging face, furrows, facial atrophy, acne scars, nasolabial folds, chin, and various other surgical defects. Survival rates for autografts of fat have been quoted anywhere from 30% to 80%. Our study uses a reproducible rabbit animal model for autotransplantation of adipose tissue and examines the histopathologic changes that occur to the graft over time. Autogenous subcutaneous fat was removed from a dorsal scapular donor site, treated to stimulate cannula damage as in liposuction, then reinjected at the base of the ear. Histologic examination of the grafts were made at 5, 10, 15, 20, 40, and 100 days after transplantation. Hematoxylin-eosin sections were graded on degree of fibrosis present (0 to 4+), viable fat (1 to 10), degree of inflammation (0 to 4+), and neovascularization (+ or -). Viability of fat decreased from 8.5 to 10 at 5 days to 2 viability at 40 days. Acute inflammation peaked at 10 days, followed by the chronic inflammatory response with macrophages and multinucleated giant cells scavenging the dying fat graft. Neovascularization began at 5 days, peaked at 10 days, and remained constant thereafter only at the edge of the graft. Microcysts appeared at 15 days and increased in number in proportion to the decrease in viable fat. In summary, the temporal histologic events are progressive fibrosis; decreased amount of viable fat; inflammation beginning with a neutrophilic response, later a macrophage and giant cell response; and neovascularization at the periphery of the graft insufficient to maintain graft viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1990

Three-dimensional reconstruction of the temporal bone.

Study of the complex anatomy and pathology of the temporal bone has traditionally used microscopy which permits analysis in only two dimensions. Recent advances in bioimaging technology have permitted visualization and reconstruction of computed tomography images in three dimensions. We have developed a technique that applies this technology in the imaging and reconstruction of human temporal bones. Data taken from serial histologic sections of the temporal bone are entered into a computer. The sections are edited and, through the use of specially developed software, a realistic three-dimensional reconstruction is produced. The reconstructed image can be rotated along any of three axes, and structures within the temporal bone can be isolated for more detailed analysis. Applications for the study of pathologic conditions of the temporal bone will be discussed.

Adult↗

PubMed1989

Ultrastructural analyses of acellular glomerular basement membranes and mesangial matrix in a spontaneously diabetic rhesus monkey.

Renal changes similar to those considered diagnostic for diabetes in humans are infrequently observed in spontaneous noninsulin-dependent (NID) diabetic monkeys. In the current study, renal cortical tissue blocks are rendered acellular to demonstrate glomerular basement membrane (GBM) and mesangial matrix (MM) changes in a naturally occurring NID diabetic rhesus monkey (Macaca mulatta). Transmission electron micrographs of these specimens show axial MM accumulations with numerous striated collagen fibrils that frequently extend onto internal (endothelial) surfaces of peripheral GBM. The outer (epithelial) component, although compact, appears bilaminar due to folded external surfaces not coinciding with similar irregularities on internal surfaces. By scanning electron microscopy, external surfaces of sclerotic GBMs are extensively wrinkled and, following cryofracture, show congestion and expanded MM. A fenestrated meshwork of MM, which appears less dense and compact than epithelial BM, extends from axial regions onto GBM internal surfaces. The true thickness of randomly sampled peripheral GBM thickness (approximately 400 nm) is approximately double that of normal rhesus GBM. Diabetic GBMs exhibit ruthenium red positivity for surface polyanions with linear site densities not significantly different from normal. These observations indicate that sclerotic GBMs in diabetic rhesus monkeys closely resemble those seen in human end-stage diabetic glomerulopathy and suggest that this nonhuman primate may offer an excellent model for studies of chronic diabetic BM disease.

Animals↗

PubMedDate not supplied