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Homologue of Slimb (HOS) is the substrate-recognizing component of the SCFHOS-Roc1 E3 ubiquitin protein ligase. This ligase mediates ubiquitination of the inhibitor of NF-κB transcription factor (IκB). We have found that HOS is highly expressed in a number of human cancer cell lines. The rates of the HOSgene transcription as well as HOS mRNA and protein levels were up-regulated in cells treated with mitogens or transfected with the inducers of mitogen-activated protein kinase pathway. Conversely, mitogen withdrawal strikingly reduced HOS levels during differentiation of mouse myoblasts. Activators of mitogen-activated protein kinase accelerated IκBα degradation and increased NF-κB transcriptional activity. Inhibition of HOS function via expression of dominant negative HOS (HOSΔF) initiated mouse myoblast differentiation and prevented Ras-mediated acceleration of IκBα degradation as well as NF-κB trans-activation and transformation of NIH3T3 cells. These data link the induction of HOS in proliferating cells with mitogen-signaling-dependent inhibition of cell differentiation and promotion of cell transformation.

Abstract The localization of Ca²⁺-ATPase activity was examined ultracytochemically in the endolymphatic sac (ES) of the 1-day-old chick. The reaction products showing Ca²⁺-ATPase activity were localized along the microvilli and the apical cell membranes of the epithelial cells of the ES. The lateral cell membranes also showed mild activity. These reactions were completely abolished when either Ca²⁺ or ATP was omitted from the incubation medium. The results suggest that Ca²⁺-ATPase plays a significant role as a Ca²⁺ pump for regulation of the Ca²⁺ concentration in the endolymph of the ES.

AbstractA gentle tap on the forehead evoked short-latency motor responses in the sternocleidomastoid muscle, which may be vestibulocollic reflexes with characteristics similar to those elicited by clicks. We tested this paradigm in subjects standing upright, in order to determine the differential effects of taps on the forehead on the patterns and latencies of spinal stretch and vestibulospinal reflexes, which are important for postural control. Taps on the forehead elicited short-latency inhibitory electromyographic responses in both gastrocnemius muscles with a mean latency of 48.3 ± 3.1 ms (onset) to 98.3 ± 6.3 ms (end). Taps on the sternum elicited similar responses from the gastrocnemius muscles, indicating that vestibular stimulation is not essential for eliciting these responses. Both responses may play a role in predetermining the strategy for correcting body perturbations. The actual reflex is probably elicited by somatosensory input from the neck, which converges with vestibular input for the multisensory control of posture.

This study examines the effectiveness of physical exercise, during a prepathology state, on locomotor balance compensation after subsequent unilateral labyrinthectomy in squirrel monkeys. An experimental group underwent 3 hr. of daily running exercise on a treadmill for 3 mo. prior to the surgery, whereas a control group was not exercised. Postoperatively, the locomotor balance function of both groups was tested for 3 mo. There was no significant difference in gait deviation counts in the acute phase of compensation. However, in the chronic compensation maintenance phase, the number of gait deviation counts was fewer in the exercise group, which showed significantly better performance stability.

Amino acids were assayed by HPLC in bilateral vestibular nuclei from normal squirrel monkeys (n=3) and those 10-month post-unilateral labyrinthectomy (n=4). Findings of vestibulo-spinal and vestibulo-oculomotor functions were identical for both groups. No left-right asymmetry of amino acids was found within either group, nor between groups with the exception of GABA: GABA was significantly reduced in the bilateral vestibular nuclei of the 10-month post-lesion animals. This may be indicative of a reduction of cerebello-vestibular inhibitory control which could be secondary to the reduction of excitatory inputs to the system.

When combined vestibular and visual (optokinetic) stimuli were given to squirrel monkeys in a direction and phase mismatching sinusoidal mode (in yaw plane), five of six monkeys exhibited actual emesis during three repeated exposures on separate trial days. Two animals vomited on two trial days and three animals, on one day. The incidence took place in 38.9% of the total trial days. When the identical vestibular and visual stimuli were given individually, the effect was negligible, thus confirming each stimulus magnitude was not stressful enough to produce emesis when used separately.

Using serially sectioned human temporal bones, endolymphatic volumes of utriculus and sacculus were measured with the aid of a computer. The mean of the utricular volume was 8.187 mm3, and the saccular volume, 2.096 mm3. The former was 3.9x the latter. The surface area of the macula utriculi was 3.271 mm2, and the macula sacculi was 2.188 mm2. The former was 1.5x the latter. The study using pathologic temporal bones (Meniere's disease, otosclerosis, and otitis media chronica) showed that the utricular volume could indeed increase, and the saccular membrane was found to be more fragile than the utricular membrane in those diseased conditions.

In order to characterize postural ataxia associated with peripheral vestibular lesions, we have developed a T-perch recording system suitable for squirrel monkeys (tree-living primates). This system includes strain gauges for detecting movement of the vertical shaft in the directions of anterior-posterior and left-right. Simultaneously we recorded electroencephalogram (EEG), vertical eye movement, electrocardiogram (ECG) and respiration (by pneumography). Representative Dynographic records (obtained during sleep) after unilateral and bilateral (two-staged) labyrinthectomy showed the frequent occurrence of phasic body movements: slow deviations to the lesion side and the frontward and subsequent quick rightings which occurred almost synchronously with the sleep becoming shallow (judged by EEG).

To measure the endolymphatic and perilymphatic spaces, we used human temporal bones (horizontal serial sections) under two selection criteria: absence of otological pathology, and absence of artifact in the membranous labyrinth (boundary between endolymphatic and perilymphatic spaces) maintaining an intact structural integrity. Under magnified projection, the area of scala tympani, scala vestibuli, scala media, vestibular endolymphatic space, and vestibular perilymphatic space were measured separately, using a microcomputer digitizing tablet. Three repeated measurements were obtained and averaged. The mean total labyrinthine fluid space was 204.5 mm3; the mean total endolymphatic space was 38.1 mm3 and mean total perilymphatic space 166.4 mm3. The mean total vestibular fluid space was 120.9 mm3 and mean total cochlear fluid sapce 83.6 mm3. In the vestibule, the perilymphatic space occupied 74.8%, and the endolymphatic space, 25.2%, whereas 90.8% of the cochlear fluid space was occupied by perilymph.

The enzymes for synthesis of catecholamine, tyrosine hydroxylase (TH), dopamine β-hydroxylase (DBH), and phenylethanolamine N-methyl transferase (PNMT), have been immunocytochemically localized in the guinea pig cochlea. Two groups of catecholamines-containing neurons could be distinguished. The first group, which was TH-positive/DBH, PNMT-negative, was found in the inner spiral bundle and the tunnel spiral bundle. The other group was TH, DBH-positive/PNMT-negative, and was found around the blood vessels. The immunocytochemical evidence obtained in this experiment suggests that the catecholamines should play a functional role in the guinea pig cochlea.

To characterize the functional role of the descending medial longitudinal fasciculus (d-MLF) in vestibular compensation, vestibulo-ocular and vestibulo-spinal balance functions were studied comparatively in the squirrel monkey. When a unilateral lesion was made on the d-MLF, the animals showed a slight head deviation to the intact side, slight locomotor ataxia and irregular spontaneous nystagmus. About 2 months later, the ipsilateral labyrinthectomy was placed, and the compensatory process was compared between 3 experimentals and 3 controls (labyrinthectomy without pre-lesion). During the acute stage of the vestibular compensation, locomotor deviation was clearly greater in experimentals than those in controls. However, no significant difference existed in the final attainment and maintenance of the balance. The same result was found in the spontaneous nystagmus, although the difference in the two groups was less remarkable.

Head and eye movements in the yaw plane were recorded during and after optokinetic stimulation in squirrel monkeys. 1) Phasic or tonic head deviations to the side of the ocular quick phase occurred in 94% of total recordings (n = 50) during the perstimulus period, and in 75% of recordings (n = 49) during the poststimulus period. Magnitude of mean head deviation was significantly different between perstimulus and poststimulus periods. 2) Head nystagmus associated with eye nystagmus was consistently observed in seven of nine squirrel monkeys during optokinetic stimulation. Squirrel monkeys are thereby less prone to display head nystagmus than either guinea pigs, pigeons or chickens. 3) Slow phase speeds of coupled head and eye nystagmus were subjected to statistical analysis. A highly significant negative correlation was found between slow phase head and eye speeds. The correlation coefficient was −0.81 at 60°/sec stimulus (n = 119) and −0.72 at 100°/sec stimulus (n = 131). The gaze speed, calculated by summing the head and eye speeds, was 59.1 ± 6.8/sec at 60°/sec and 92.2 ± 11.4 at 100°/sec stimulus. There was no significant difference between the gaze speed in a free head condition and the eye speed when the head was fixed.

• A 19-month-old boy had adrenocerebroleukodystrophy and unusually severe cochlear nerve degeneration and demyelination, a condition in advance of that expected from known disease entities. We report the only known temporal bone study in adrenocerebroleukodystrophy.(Arch Otolaryngol 102:722-726, 1976)

• A 19-year-old woman with cryptococcal meningitis died as a result of her disease, in spite of both intravenous and intraventricular administration of amphotericin B. Gross and microscopic examinations revealed multiple cysts containing Cryptococcus neoformans within the central nervous system. Studies of the temporal bones revealed both neural and end organ destruction with the presence of Cryptococcus when stained by Gomori methenamine silver nitrate method. We present the results of audiometric and vestibular examinations. The case history depicts a progressive neurological involvement by Cryptococcus.(Arch Otolaryngol 101:577-583, 1975)

Spontaneous, positional, and paroxysmal positional nystagmus were studied before and after sectioning the superior division of the vestibular nerve and the anterior vestibular artery in squirrel monkeys. Histopathologic study of the temporal bones confirmed the degeneration of the macula utriculi with release of statoconia, but failed to identify the released utricular statoconia within the vestibular endolymphatic space in any animal.Postoperatively the animals consistently demonstrated direction-fixed spontaneous nystagmus until the end of the experiment (five months). Positional tests and Dix-Hallpike maneuver occasionally changed the intensity of the spontaneous nystagmus, but never elicited paroxysmal positional nystagmus.Possible reasons for not demonstrating paroxysmal positional nystagmus in the squirrel monkey are as follows: a resorption of statoconia; slight morphological alteration of the sensory epithelia of the posterior cristae; interference of the posterior crista function due to partial collapse of the membranous ampulla; the existence of interspecies difference; or possibly a faulty hypothesis regarding the etiologic mechanism of benign paroxysmal positional vertigo.

An improved task of locomotor balance for use by squirrel monkeys, employing a shuttle-avoidance paradigm, consisted of a straight alley runway with pressure sensors on the floor to detect footsteps. Training and pre-experimental baseline performance for animals used later in vestibular end organ deafferentation experiments, etc. were described. Subjects learned the task within a few days (Mdn= 5.81 days to first criterion session) as indicated by the skewed distribution of trial sessions to criterion. This test is an improvement over a perviously described measure of locomotor balance in that it eliminates the requirement of physical fitness inherent in the other task.

An effort to find evidence of electrodermal response in the squirrel monkey (Saimiri sciureus), as found in man, some infra-human genera of Simiae, and some lower mammals and amphibians, failed to locate an example. Given anatomical considerations, the availability of this response in Saimiriwas suspected. In this study, using the skin conductance (constant voltage) method, monophasic electrodermal response as a result of novel or startle stimuli presentation was detected and a range of skin conductance level for test cases was determined.

Pilots and astronauts experience fluid shifts in variable gravity. Acute effects of fluid shifts on the cardiovascular system were monitored on NASA's KC‐135 aircraft during parabolic flight The variability of R‐R intervals in the electrocardiogram was measured as an indication of vagal cardiac neural activity. R‐R intervals were measured during the gravity transition from 2‐G to 0‐G produced by parabolic flight to assess the involvement of the autonomic nervous system in regulating the acute effects of fluid shifts. In seven subjects, a BoMed noninvasive continuous cardiac output monitor (NCCOM 3) monitored thoracic fluid index (TFI, ohms), heart rate (bpm), and cardiac output (1/min). Data were stored on a lap‐top computer with the subject in one of four postures: sitting, standing, supine, and semi‐supine, during one of four sets of eight to ten parabolas. Five seconds of data were averaged: before parabola onset (1.3‐G); parabola entry (1.9‐G); 0‐G; and parabola exit (1.7‐G). Three to eight parabolas were averaged for subjects in each posture; the mean for each posture was calculated. In each of five additional subjects, the coefficient of variation was calculated by dividing mean value by the standard deviation of 3 to 15 R‐R intervals. Eight to ten parabolas were averaged for each postural set. Compared with values collected before 0‐G, standing values during 0‐G showed that the thoracic fluid index decreased 2.5 ohms, heart rate decreased 22 bpm, and cardiac output increased 1 L/min. During sitting, thoracic fluid index decreased 1.25 ohms, heart rate decreased 10 bpm, whereas cardiac output increased 0.5 L/min. In the supine position, thoracic fluid index and heart rate were constant whereas cardiac output decreased 0.55 L/min. In the semi‐supine position, thoracic fluid index and heart rate were constant. Compared with values collected from 2‐G and 0‐G the coefficient of variation increased 66.4% in the standing position, 53.4% in the sitting position, and 43.3% in the semi‐supine position and decreased 11.6% in the supine position. The data indicated that cardiovascular changes are dependent on posture and gravity. During the four sets of parabolas in the four different postures, the greatest and smallest changes were observed in the standing and supine positions, respectively, during 0‐G. Fluid shifts from the legs to the thorax occurred during 0‐G in the supine and standing positions. The high values of the coefficient of variation at the onset of 0‐G suggest that vagal cardiac neural activity increases, but not significantly, in all positions except supine.

• The facial recess approach permits surgical access to the round window area. This route is used in patients who are undergoing cochlear implantation. To evaluate the feasibility of this procedure in children as compared with adults, serial sections of temporal bones were used t[ill] measure the surgical dimensions of the facial recess. No statistically significant differences in the dimensions of the facial recess or the extended facial recess approaches were found between children and adults. The relationship of the facial and chorda tympani nerves to the annular plane exhibited no change with postnatal growth. These structures translate posteriorly and laterally toward the annular plane as they descend within the temporal bone. Therefore, the facial recess approach represents no greater hazard in a child than in an adult.(Arch Otolaryngol Head Neck Surg 1988;114:534-537)

• The temporal bone findings of a patient with VATER syndrome are reported. The VATER syndrome is a nonrandom association of anomalies including vertebral, anal, tracheoesophageal, radial, and renal defects. This patient had multiple congenital anomalies: tracheal agenesis with associated laryngoesophageal cleft and tracheoesophageal fistula, tetralogy of Fallot, single umbilical artery, and imperforate anus with cloaca. To our knowledge, there have been no reports of the temporal bone findings in the VATER syndrome. Our patient had anomalous configuration of lateral semicircular canal and an abnormally high location of the utricle and saccule. The VATER syndrome seems to be due to faulty mesodermal development during the first five weeks of gestation, which, according to the findings reported here, can also involve the temporal bones as well.(Arch Otolaryngol Head Neck Surg 1986;112:416-419)

• Temporal bone metastasis of classic testicular seminoma is extremely rare in the English literature. Except for a clinical case report of seminoma in the temporal bone, to our knowledge there is no temporal bone pathology report of secondary seminoma. In the left temporal bone of the present case, tumor cell infiltration was found in the external auditory canal, tympanic membrane, middle ear cavity, tympanic and mastoid mucosa, tensor tympani muscle, and so on.(Arch Otolaryngol Head Neck Surg 1986;112:102-105)

• We report a rare case of bilateral sudden and profound hearing loss caused by bilateral temporal bone metastasis from a primary adenocarcinoma of the tail of the pancreas. The hearing loss was the patient's only reason to seek medical care. Seventh nerve involvement was very minimal, when compared with that of the eighth nerve.(Arch Otolaryngol 105:196-199, 1979)

• Acoustic reflex thresholds for pure tones and broad-band noise were measured before and after treatment of nine squirrel monkeys. Experimental sensorineural hearing loss was created in six monkeys by ototoxic drug administration (gentamicin) and in three monkeys by exposure to intense sound. Extent of cochlear damage was assessed histopathologically, in the case of permanent loss induced by the ototoxic agent, and inferred from exposure history, in the case of the reversible loss induced by exposure to intense sound. Posttreatment changes in relationships among acoustic reflex thresholds (noise-tone difference [NTD]) reflected approximate degree of cochlear damage. Serial measurement of changes in the NTD in acoustic reflex thresholds appears to be a worthwhile and useful technique for monitoring sensorineural levels in the squirrel monkey.(Arch Otolaryngol 104:559-563, 1978)

• The two principal components of impedance audiometry, the tympanogram and acoustic reflexes, were measured preoperatively and postoperatively in seven squirrel monkeys subjected to experimental middle ear surgery. A probetone frequency of 1,200 Hz yielded both tympanograms and acoustic reflex thresholds roughly comparable to analogous data in humans at a probe-tone frequency of 220 Hz. Both tympanograms and acoustic reflex thresholds could be obtained reliably and with comparative ease. In general, postoperative data were modified in the expected fashion by the experimental middle ear surgery. Impedance audiometry appears to be a worthwhile and useful technique for monitoring middle ear status in the squirrel monkey.(Arch Otolaryngol 104:214-224, 1978)

A patient with bilateral acoustic neurofibroma was repeatedly examined audiometrically during the progression of the disease. Postmortem, the temporal bone disease was studied to confirm severe progressive hearing dysfunction found in serial audiometric examinations. Results of the electronystagmographic examination showed bilateral absence of caloric nystagmus. Bilateral absence of the response was also shown by the galvanic body sway test.

Temporal bones were studied in five cases of acute pneumococcal meningitis. All patients had purulent labyrinthitis bilaterally. In addition, two temporal bones from one patient showed a hematogenous spread of the disease. Destruction of the stria vascularis and massive hemorrhage within the cochlear duct were observed. This was probably caused by the vascular affinity of the pneumococci at the time of persistent pneumococcal bacteremia. The findings suggest the existence of primary bacterial endolymphatic involvement, caused by the destruction of labyrinthine vessels.

Vestibular end organ mapping (surface preparation) was performed in squirrel monkeys by using succinic dehydrogenase staining. Comparing sensory hair cell counts and surface area measurements of the squirrel monkey to those of man and the guinea pig, the values obtained from the squirrel monkey were between those of man and the guinea pig. When regional (central versus peripheral) cell density was compared, the density of the peripheral area was 1.62 × more on the average than that of the central portion.

Damped pendular rotation nystagmus was studied in squirrel monkeys before and after otolith end organ ablation (two-stage operations). After each operation, the nystagmic slow phase eye speed toward the operated side was reduced (to about 73% of that before the operation) and that to the nonoperated side did not show any marked change. A few subjects showed spontaneous nystagmus with amphetamine administration but only in dark (could not be found in light) immediately after the operation, and it disappeared rapidly. Therefore, this post-ablative reduction of the slow phase eye speed is considered to result from the loss of inputs from the otolith end organs.

Simultaneous application of the rotatory stimulus with a constant angular acceleration (1°/sec2) did not clearly improve the optokinetic pursuing ability in squirrel monkeys, even though the directions of vestibular and visual stimuli matched.

We used light microscopy to study 87 human temporal bones (from 47 cases) with no known otological disorders, and found that certain cases had sclerotic changes around the endolymphatic duct and sac. Changes included fibrosis, hyalinization, psammoma formation, and thickened vascular walls. The findings were subjected to statistical analysis, which indicated that most of the changes could be positively correlated with increases in age.

Bericht über eine 47-jährige Frau mit Schwindelattakken, Ohrensausen und beiderseitigem Hörverlust. Eine Audiogrammserie über einen Zeitraum von 15 Jahren zeigt auf dem linken Ohr eine fluktuierende kombinierte Schwerhörigkeit, auf dem rechten eine leichte Innenohrschwerhörigkeit. Die histologische Untersuchung der Felsenbeine (Exitus durch Lebererkrankung) ergab eine Otosklerose beiderseits. Auf dem linken Ohr dehnte sich der Otoskleroseherd bis zum N. utricularis und dem Nerv der lateralen Ampulle aus, ankylosierte die Fußplatte des Steigbügels und verformte die laterale Wand der Cochlea. Auf dem rechten Ohr war der Herd auf den unteren Teil des Promontoriums und auf die Nische des runden Fensters begrenzt.

Polyamine synthesis increases in response to injurious stimuli including axotomy and denervation. Reduced eye nystagmus and head-deviation have been observed in unilateral labyrinthectomized (UL) guinea pigs treated with an inhibitor of polyamine synthesis, a-difluoromethylornithine (DFMO). We quantified polyamines in the lateral vestibular nuclei (LVN) of control and UL squirrel monkeys during the phase of vestibular compensation (VC) and performed an experiment to determine if DFMO reduces nystagmus previously observed in the guinea pig. Polyamines were detected in the LVN of control and UL squirrel monkeys. Putrescine and spermidine increased in the ipsilateral LVN 3 days after UL with no change in the contralateral LVN. No left-right differences were noted in the 5-day post-UL monkey. DFMO reduced nystagmus in a UL squirrel monkey. These findings suggest that polyamines are important in vestibular function and may contribute to nystagmus observed in VC.

Asymmetry of vertical optokinetic after-nystagmus (OKAN) was studied in 6 squirrel monkeys. The slow-phase eye velocity (SPEV) of upward OKAN first-phase (OKAN-I) increased with increasing stimulus velocity, whereas the SPEV of downward OKAN-I diminished. The time constant of OKAN-I was shortened with the increase in stimulus speed in both directions. With a downward stimulus, the short stimulus duration failed to produce OKAN second-phase (OKAN-II) (upward slow-phase); however, with an increase in stimulus duration, the percentage appearance increased. There was no change in percentage appearance, regardless of the duration of upward stimulus. The asymmetry of OKAN-I and that of OKAN-II differed to a certain degree.

At the present time, neither the etiologic factors nor the pathophysiologic mechanisms that lead to the development of endolymphatic hydrops or Ménière's disease are known; however, the anatomic-pathologic alterations in the labyrinth that are produced by the disease are well-documented. Undoubtedly, what is not known is responsible for the controversial status and questionable benefit that surgical decompression and drainage procedures have upon the endolymphatic system.

• If entrapment is a critical factor in pathogenesis, the lower incidence of Bell's palsy in children compared with adults may have an anatomical basis. Histologic sections of 20 temporal bones from children younger than 2 years were examined to determine the diameter of the facial nerve and fallopian canal at the meatal foramen and in the labyrinthine segment. No statistically significant difference in the nerve/canal ratios in these areas was found. Comparisons were made with similar data from 10 adult temporal bones. The nerve/canal ratios in the labyrinthine portion were similar in both age groups; however, the ratio at the meatal foramen was significantly smaller in children. This may be due, in part, to growth of the vertical crest, which was found to increase considerably in length and width by adulthood. These results suggest that the facial nerve is not as tightly contained at the meatal foramen in children and provides a possible explanation for the relative infrequency of Bell's palsy in this age group.(Arch Otolaryngol Head Neck Surg. 1990;116:1030-1035)

• Three infants with cerebrospinal fluid otorrhea and recurrent meningitis due to Mondini dysplasia have been treated at Baylor College of Medicine, Houston, Tex; 39 other patients with this association have been described. This review highlights the characteristics and embryologic basis of the malformation. The clinical evaluation of an infant with recurrent meningitis is outlined, and the importance of brain-stem response audiometry and thincut computed tomography of the temporal bones is discussed. Surgical management depends on the functional status of the dysplastic ear; usually, a stapedectomy is performed and the vestibule is obliterated. Although the surgical failure rate is 30% after one procedure, early identification of the dysplasia and prompt surgical management diminish morbidity and mortality and permit early habilitation of the child with congenital hearing impairment.(Arch Otolaryngol Head Neck Surg. 1990;116:608-612)

In a case of bilateral tympanosclerosis, in addition to the tympanosclerotic changes, the round (or ovoid) concentric lamellated bodies in the right tympanic cavity (epitympanum and mesotympanum) and mastoid cavity were found. The pathogenesis of tympanosclerosis was discussed in conjunction with those concentric lamellated bodies including its relationship with Pacinian body or middle ear corpuscle.

Using serially sectioned human temporal bones, the volumes of otoconia masses were compared between young children and elderly people. The latter group had significantly less otoconia volume than the former group, both in the macula utriculi and macula sacculi. The ratio between macula utriculi and macula sacculi was 100: 70 in the young group, whereas it was 100: 35 in the elderly group. Thus, the macula sacculi in the elderly group showed the severest otoconia reduction.

The course and branches of the internal auditory artery (IAA) were studied in 7 vertically-sectioned normal adult human temporal bones, and three-dimensional reconstructions of the anatomical structures were made with the aid of a computer system. Single IAAs existed in 3 or 7 temporal bones whereas double IAAs existed in 4. The IAA ran either between the facial nerve and the VIIIth nerve, or on the inferior-posterior surface of the VIIIth nerve at the porus. Branching and anastomosis of the IAA were highly variable in the middle to proximal portion of the internal audiotry canal (IAC). The anterior vestibular artery ran on the anterior surface of the superior vestibular nerve, and the vestibulocochlear artery ran on the inferior surface of the inferior vestibular nerve. The main cochlear artery ran at the center of the cochlear nerve near the fundus. The course of the vessels was less variable at the distal portion of the IAC than at the proximal portion.

For the purpose of assisting the accurate topological identification of the internal auditory canal (IAC) during surgery through the middle cranial fossa, we conducted a dimensional study around the IAC using histologically prepared temporal bones. The anterior margin of the porus acousticus, the posterior margin of the porus acousticus, and the center of the fundus were located 19.7 mm, 16.8 mm, and 8.2 mm from the center of the malleus head, respectively. The angles formed by lines connecting those three points of the IAC and the ossicles were also measured. These values could be of help to identify the accurate localization of the IAC using the ossicles as surgical landmarks, when available. The common crus, i.e. a critical inner ear structure for hearing preservation, was also studied. The distance from the medial side of the common crus to the posterior wall of the IAC was relatively constant. However, the distance from the medial side of the common crus to the surface of the posterior cranial fossa was variable. Measurements in the vertical sections showed that the thickness of the superior bony wall of the IAC was similar to that of the cochlear otic capsule which should be kept unexposed for hearing preservation.

Temporal bone pathology of 3 cases with large unilateral acoustic neurinoma (AN) and 2 cases with large bilateral AN (neurofibromatosis 2; NF2) were studied. One case with unilateral AN was diagnosed as neurofibromatosis 1 (NF1). Unilateral AN had distinct borderlines at the fundus in 5 of 12 examination points between tumor tissues and nerve fibers, but only 1 of 12 was distinct around the porus acousticus. Bilateral AN showed no distinct borderlines at the fundus and around the porus acousticus. These findings suggest that clear separation of the VIIth or VIIIth nerve from large tumors is very difficult, especially in cases of bilateral AN. Geniculate ganglion cells of tumor origin on ears were fairly well preserved in 2 cases with unilateral AN and 1 case with bilateral AN. Well preserved geniculate ganglion cells could be dependent on blood supply not from the internal auditory artery.

Procedures designed to evaluate the severity of motion sickness have included subjective reporting of changes in salivation. In order to increase objectivity, we studied the sodium concentration of saliva, which is directly related to the flow rate. Healthy adults with normal vestibular function underwent a modified Coriolis Sickness Susceptibility Index (CSSI) test, utilizing a staircase profile. Saliva was collected without interrupting the stimulus by means of cotton placed beneath the subject's tongue for one minute. Samples were obtained 5 min prior to stimulation, 30 and 45 min following stimulus onset, and/or upon reaching the "nausea II" endpoint. Saliva for analysis by atomic absorption spectrophotometry was obtained by centrifugation of the cotton. A significant difference in sodium concentration was found between the baseline and 30-min sample (p<0.01). Although the amount of salivation was rather variable, the pattern of changes in sodium concentration was similar in all experimental cases.

β2-Glycoprotein I (β2-GPI) consists of five repeats of a homologous domain. We designed a series of human β2-GPI mutant genes, ie, three mutant genes lacking the domain(s) present in the NH2-terminal region and two of those present in the COOH-terminal region. These mutant genes were expressed in Spodoptera frugiperda insect cells (Sf9) infected with recombinant baculoviruses and the mutant proteins were secreted into the culture medium. The molecular mass of the purified mutant proteins, estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was fairly consistent with the size calculated from their nucleotide sequences. Binding of β2-GPI to solid-phase cardiolipin (CL) was diminished by the deletion of the fifth domain (domain V) from its complete structure. Thus, the phospholipid binding site of β2-GPI is located on its domain V. Monoclonal anti-CL antibodies (aCL) derived either from NZW x BXSB (WB) F1 mice or from patients with antiphospholipid syndrome bound directly to the domain V-deleted mutant protein (DI-IV) absorbed not only on an oxygenated but also on a plain polystyrene surface. We conclude from this study that the epitope for aCL is exposed on a comformationally changed structure of β2-GPI by interacting with negatively charged phospholipid or on the mutant protein, DI-IV.

The vestibular ganglia of adult squirrel monkeys (Saimiri sciureus) were studied with the aid of light and electron microscopy. The vestibular ganglia are formed by small and large neurons (perikarya). The perikarya's outermost surface is surrounded by 2–20 lamellae of compact myelin. The compact myelin sheath varies its thickness around one perikaryon. The sheath generally thins out in the vicinity of the axon hillock. Occasionally, the compact myelin transforms completely into loose myelin for a length of 2–5 μ. Two to eight lamellae of loose myelin usually face the cytoplasm of the neurons. This myelin arrangement is constant in the majority of the cells examined regardless of shape and/or size. Large myelinated perikarya form the majority of the ganglion cells. There are, however, a few neurons that lack a true compact myelin sheath. Others are surrounded by very few lamellae of loose myelin. The general morphology of the neurons was compared to the available literature on other species. Possible variation on the myelination pattern due to fixation differences, and variation on perikaryal size due to the angle of cut and irregular shape of the cells are also discussed.

The effects of transection of the crossed olivo-cochlear bundle (COCB) on auditory brain stem responses (ABR) were investigated in the cat. The threshold, the amplitude and the peak latency of waves I-1V, and interpeak latencies were compared before and after transection of the COCB. No significant change was found in these parameters of ABR after elimination of the COCB.

Bericht über eine 47-jährige Frau mit Schwindelattakken, Ohrensausen und beiderseitigem Hörverlust. Eine Audiogrammserie über einen Zeitraum von 15 Jahren zeigt auf dem linken Ohr eine fluktuierende kombinierte Schwerhörigkeit, auf dem rechten eine leichte Innenohrschwerhörigkeit. Die histologische Untersuchung der Felsenbeine (Exitus durch Lebererkrankung) ergab eine Otosklerose beiderseits. Auf dem linken Ohr dehnte sich der Otoskleroseherd bis zum N. utricularis und dem Nerv der lateralen Ampulle aus, ankylosierte die Fußplatte des Steigbügels und verformte die laterale Wand der Cochlea. Auf dem rechten Ohr war der Herd auf den unteren Teil des Promontoriums und auf die Nische des runden Fensters begrenzt. This report summarizes audiologic and temporal bone findings in a 47-year-old white female with recurrent attacks of vertigo, tinnitus, and bilateral hearing loss. A series of audiograms, obtained over a 15-year period, showed a fluctuating mixed (sensorineural and conductive) hearing loss with a relatively flat configuration in the left ear and a relatively stable, mild sensorineural loss with a sloping contour in the right ear. Temporal bone studies revealed the existence of otosclerotic foci bilaterally. In the left ear, the otosclerotic focus had grown close to the utricular and lateral ampullary nerves, displaced and ankylosed the stapedial footplate, invaded the endosteal zone (1,000–2,000 Hz area), and deformed the lateral cochlear wall. In the right ear, the otosclerotic invasion was limited to the inferior portion on the promontory (vestibular cecum) and round window niche.