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Biomedical subjects

R Hinojosa

Publications and source records attributed to R Hinojosa.

At least 19 recordsLinked to original sources
PubMed1991

Histopathology of metastatic temporal bone tumors.

Temporal bone metastasis is now being reported with increasing frequency. To understand the process of temporal bone metastasis, complete histologic evaluation of the temporal bones is essential. In this study, 60 temporal bones from 33 patients were evaluated. Different patterns of temporal bone involvement were noted depending on the mode of spread to the temporal bone. Involvement of the temporal bone usually occurs late in the disease process and is often asymptomatic.

Adolescent↗
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

The histologic characteristics of the core of the fissula ante fenestram.

In earlier studies of perilymphatic fistulae, we described their histologic criteria and the clinical criteria for the identification and prediction of patencies of the labyrinth capsule related to disorders of hearing and balance. These patencies were either of the fissula ante fenestram or of the round window niche-posterior canal ampulla fissure. The permeability of the fibrous core of a patent fissula ante fenestram has been questioned, authors of some earlier articles arguing that the tissue is loose, others that it is dense. This study demonstrates loose fibrous and cellular structure in the fissula's tract, dense collagen at the circumference. The loose arrangement of tissue suggests that fluid can pass through this patency, and it appears similar to that of the spiral ligament which has been shown to contain perilymph by way of intercellular communications with the perilymphatic space.

Ear, Middle↗
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

Clinical diagnosis of anterior inferior cerebellar artery thrombosis. Autopsy and temporal bone histopathologic study.

A patient having the diagnosis of an anterior inferior cerebellar artery insufficiency died 36 hours after the onset of the symptoms that allowed this diagnosis. The special features of this study include a known symmetric 40-dB hearing loss 1 year prior to the onset of the symptoms, the noted decrease in hearing and severe vertigo heralding the vascular accident, the ensuring neurologic deficits, and the short duration of the patient's life after the onset of her symptoms. The patient's clinical course and the histopathologic findings of the brain stem involved the vestibular nuclei, facial nerve, nuclei of nerve V, restiform body and middle cerebellar peduncle and labyrinth including loss of sensory epithelium of the cochlea and vestibular system and the ganglion cells of Scarpa's ganglion. These findings are correlated with previous animal studies and those of Reye's syndrome. To the authors' knowledge this is the first report of a temporal bone histopathologic study from a patient having had the diagnosis of a labyrinthine arterial vascular accident.

Aged↗
PubMed1990

Surgical inferences from study of temporal bones with glomus jugulare tumor.

Over the past few years, considerable advances have been made in the surgical treatment of glomus jugulare tumors. The long-term results of such surgery for cure of these tumors has yet to be established, however. We have reviewed the temporal bones of two patients who had glomus jugulare tumors. Such study provides a special opportunity to evaluate the major critical areas of involvement of these tumors, which bears on the long-term results of surgery, and is important in developing treatment to cure these benign, though aggressive, tumors.

Carotid Artery, Internal↗
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

Mediastinal, left, and right atrial pressure variations with different modes of mechanical and spontaneous ventilation.

Variations in mediastinal, left, and right atrial pressures (MedP, LAP, RAP, respectively) were measured by means of catheters and tubes positioned in ten patients with nonvalvular cardiac surgery. For each pressure, a maximum, minimum, and mean value was determined in relation to its oscillations during the respiratory cycle. Thus, we compared the variations in MedP, LAP, and RAP in controlled mechanical ventilation (CMV), CMV with 5 cm H2O PEEP, synchronous intermittent mandatory ventilation (SIMV), SIMV with 5 cm H2O PEEP, continuous positive airway pressure (CPAP), and spontaneous respiration (SR). We built an experimental model to compare the measurements obtained by air-filled tubes inserted at surgery with those obtained by esophageal balloons filled with water. The maximum MedP did not vary significantly in these patients except when SIMV and SR were compared; however, the minimum MedP diminished significantly (p less than .001) in SIMV, SIMV-PEEP, CPAP, and SR, with negative inspiratory values reaching significant proportions. The mean values of MedP, LAP, and RAP showed a similar tendency although to a lesser degree. The experimental model revealed a strong linear relation between the values obtained with air-filled tubes and those obtained with water-filled esophageal balloons (r = .99, p less than .001). These results suggest that the mean values of MedP, LAP, and RAP do not reflect the dynamic variations in ventricular filling pressure accurately, nor the important negative inspiratory peaks that appear in different types of ventilation using spontaneous cycles with and without PEEP. These inspiratory peaks can overload the left ventricle by hydrostatic gradients, and lead to pulmonary edema in susceptible patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Ontogenetic approach to cellular localization of neurotransmitters in the chick vestibule.

Gamma-aminobutyric acid (GABA) and acetylcholine (Ach) have been implicated in afferent and efferent neurotransmission, respectively, in the vestibular sensory periphery. Assuming that glutamate decarboxylase (GAD), the GABA-synthesizing enzyme, and choline acetyltransferase (ChAT), the enzyme for synthesis of acetylcholine, are located in distinct cell types of the inner ear whose maturation occurs at different times during ontogenesis, we measured these enzymes in the ampullary cristae of embryonic chicks at different stages of development. By making these measurements in parallel with electron-microscopic studies of the different cell elements of the chick vestibular sensory periphery, we found that the values of GAD activity were nearly the same from the earliest stage studied, i.e., the 13th day of ontogeny to day 18 of embryonic development, paralleling the morphologically mature appearance of the hair cells and their afferent synapses. A slight increase in enzymatic activity from day 19 of ontogeny to one day after hatching corresponded to a rise in the number of afferent synapses. In contrast, ChAT activity was practically undetectable up to day 17 of embryonic development, but rose suddenly on the 19th day, reaching 1-day-old levels by day 20 of ontogenesis in coincidence with an elevation in the number of well-developed efferent boutons. These results are in accord with the localization of GAD in the sensory cells and a localization of ChAT in the efferent nerve endings. These findings suggest that GABA and Ach are the respective neuromediators for the afferent and efferent systems.

Acetylcholine↗
PubMed1986

Theophylline binding to plasma proteins in patients with chronic obstructive pulmonary disease.

The binding of theophylline to plasma proteins was studied in samples from healthy adults at different pH values and drug concentrations and in samples from patients with chronic obstructive pulmonary disease (COPD). Binding determinations were performed by ultrafiltration and drug concentrations were measured by high performance liquid chromatography. Total plasma levels of theophylline did not influence the degree of the binding. The percentage of bound theophylline was positively correlated with pH both in vitro (r = 0.998, p less than 0.005) and in vivo (r = 0.579, p less than 0.005). Mean theophylline binding values in vivo (mean 56.3 +/- 12.5) and in vitro (mean 48.3 +/- 9.4) were significantly different. The increase in theophylline free levels detected in COPD patients was partially dependent on low pH values but the influence of other factors must also be considered. The therapeutic implications of altered theophylline binding are discussed.

Adult↗
PubMed1985

Temporal bone fractures: a histopathologic study.

Trauma or injury to the skull, if of sufficient force, may produce a temporal bone fracture. However, terms such as basilar skull fracture, labyrinthine hemorrhage, or labyrinthine concussion are inadequate in that they do not describe the precise histopathologic lesion. We carried out a histopathologic study of the 14 ears in seven patients; all the patients suffered at least one temporal bone fracture. Our objective was to review the histopathologic findings of various fracture lines through the base of the skull and correlate these with the history and clinical findings.

Adult↗
PubMed1985

Persistence of the stapedial artery: a histopathologic study.

Persistence of the stapedial artery is a rare event. Fewer than 30 cases have been reported since the discovery of this artery in 1836. We carried out a histopathologic study on three temporal bones from two patients who had this anomaly, and were able to trace the full course of the artery. In two specimens a large stapedial artery persisted and substituted for the middle meningeal artery. In the third, a small, persistent stapedial artery ended in the arterial plexus surrounding the facial nerve. Persistence is discussed in terms of embryogenesis, developmental theories, histologic findings, and clinical significance. The material suggests that the stapedial artery can persist to varying degrees.

Arteries↗
PubMed1977

Inner ear degeneration in Reye's syndrome.

A 9-year-old girl developed Reye's syndrome. On admission to the hospital on the fourth day of illness, responses for verbal stimuli had been absent, but were present for painful stimuli. Coma developed on the fourth day and was present until death ten days later. The fundus of both internal meatus showed vascular congestion of nerves with evidence of repeated hemorrhages. All structures within the endolymphatic system showed advanced degeneration, with exception of the tectorial membrane and cupulae. One ear showed vascular congestion, formation of thrombi, and free hemorrhage within the modiolus and spiral ganglion. In the other ear, congested vessels in nerves in the meatus were obstructed by swelling at the cribriform area. The degenerative changes corresponded closely to those produced experimentally in guinea pigs by interruption of arterial circulation to the inner ear.

Child↗
PubMed1976

Histopathologic features of the inner ear associated with Kearns-Sayre syndrome.

We describe the histopathologic features of the inner ear in a 19-year-old girl with bilateral total deafness associated with Kearns-Sayre syndrome. The inner ear shows advanced degree of cochleo-saccular degeneration, with almost complete absence of the organ of Corti in all turns. The spiral ganglion shows a reduction of about 60% to 70% of cells, with almost complete degeneration of nerve fibers in the bony spiral lamina. PAS-positive material was found accumulated in globules between the collapsed Reissner membrane and remains of marginal cells of the stria and in the degenerated sensory cell area of the saccular macula.

Adult↗