Faraday-Shielded dc Stark-Shift-Free Optical Lattice Clock

We demonstrate the absence of a dc Stark shift in an ytterbium optical lattice clock. Stray electric fields are suppressed through the introduction of an in-vacuum Faraday shield. Still, the effectiveness of the shielding must be experimentally assessed. Such diagnostics are accomplished by applying high voltage to six electrodes, which are grounded in normal operation to form part of the Faraday shield. Our measurements place a constraint on the dc Stark shift at the 10^{-20} level, in units of the clock frequency. Moreover, we discuss a potential source of error in strategies to precisely measure or cancel nonzero dc Stark shifts, attributed to field gradients coupled with the finite spatial extent of the lattice-trapped atoms. With this consideration, we find that Faraday shielding, complemented with experimental validation, provides both a practically appealing and effective solution to the problem of dc Stark shifts in optical lattice clocks.

Template-free synthesis of monolithic carbon xerogels with hierarchical porosity from resorcinol and formaldehyde via hydrothermal reaction

Monolithic carbon xerogels with hierarchical porosity were prepared from resorcinol (R) and formaldehyde (F) via a base-catalysed hydrothermal polycondensation reaction, without a template and supercritical drying. First, an aqueous solution of resorcinol, formaldehyde and sodium carbonate was prepared by varying R/W (25–45) and R/C (1–10k) ratios to produce monolithic RF gels. The reaction was carried out in a pressurized Teflon mould at 100 °C for 6 h to give a co-continuous pore structure via spinodal decomposition and a tenacious gel to avoid supercritical drying. Next, the RF gels were dried for 42 h at 60 °C and another 6 h at 100 °C to produce RF xerogels without cracks, followed by pyrolysis in a tube furnace at 900 °C for 2 h under N₂ flow, and then activation at 1000 °C for 2, 4 or 6 h under CO₂ flow. Finally, the carbon xerogels were characterized by SEM and N₂ adsorption–desorption measurements. Monolithic RF gels were obtained from all combinations of R/W and R/C, but the gels from R/W = 45 exhibited a co-continuous large-pore structure, providing a specific surface area (SSA) of ∼650 m² g⁻¹, which increased to 3311 m² g⁻¹ (for R/C = 10k) at 6 h of CO₂ activation without exhibiting cracks. N₂ isotherms demonstrated that micro- and meso-pores were introduced via activation, forming hierarchical porosity in combination with large pores from spinodal decomposition without using a template.

Monolithic porous carbon with hierarchical porosity via a one-step template-free hydrothermal polycondensation reaction with resorcinol and formaldehyde.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and [Formula: see text] credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5-[Formula: see text] requires at least three detectors of sensitivity within a factor of [Formula: see text] of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.

Hyperpolarizability and Operational Magic Wavelength in an Optical Lattice Clock

Optical clocks benefit from tight atomic confinement enabling extended interrogation times as well as Doppler- and recoil-free operation. However, these benefits come at the cost of frequency shifts that, if not properly controlled, may degrade clock accuracy. Numerous theoretical studies have predicted optical lattice clock frequency shifts that scale nonlinearly with trap depth. To experimentally observe and constrain these shifts in an ^{171}Yb optical lattice clock, we construct a lattice enhancement cavity that exaggerates the light shifts. We observe an atomic temperature that is proportional to the optical trap depth, fundamentally altering the scaling of trap-induced light shifts and simplifying their parametrization. We identify an "operational" magic wavelength where frequency shifts are insensitive to changes in trap depth. These measurements and scaling analysis constitute an essential systematic characterization for clock operation at the 10^{-18} level and beyond.

Development of Theoretical Descriptors for Cytotoxicity Evaluation of Metallic Nanoparticles

Motivated by the recent development of quantitative structure-activity relationship (QSAR) methods in the area of nanotoxicology, we proposed an approach to develop additional descriptors based on results of first-principles calculations. For the evaluation of the biochemical activity of metallic nanoparticles, we consider two processes: ion extraction from the surface of a specimen to aqueous media and water dissociation on the surface. We performed calculations for a set of metals (Al, Fe, Cu, Ag, Au, and Pt). Taking into account the diversity of atomic structures of real metallic nanoparticles, we performed calculations for different models such as (001) and (111) surfaces, nanorods, and two different cubic nanoparticles of 0.6 and 0.3 nm size. Significant energy dependence of the processes from the selected model of nanoparticle suggests that for the correct description we should combine the calculations for several representative models. In addition to the descriptors of chemical activity of the metallic nanoparticles for the two studied processes, we propose descriptors for taking into account the dependence of chemical activity from the size and shape of nanoparticles. Routes to minimization of computational costs for these calculations are also discussed.

Few-layer-graphene with high yield and low sheet resistance via mild oxidation of natural graphite

The mild oxidation of natural graphite was obtained via the modified Hummers method by employing an oxidation temperature of 20 °C and KMnO₄ loading of 2 g, while varying the oxidation time from 30 to 60, 90 or 120 min.

Coenzyme Q10 in combination with steroid therapy for treatment of sudden sensorineural hearing loss: a controlled prospective study

OBJECTIVE

To evaluate the therapeutic efficacy of coenzyme Q10 added to systemic steroid in patients with idiopathic sudden sensorineural hearing loss.

DESIGN

A controlled prospective study.

SETTING

Asan medical center, University of Ulsan College of Medicine.

PARTICIPANTS

Between August 2007 and October 2008, the first 60 patients diagnosed with sudden sensorineural hearing loss were managed with systemic steroid treatment for 2 weeks including 5-day hospitalisation. And the second 60 patients were managed with coenzyme Q10 for 2 weeks added to previous management.

MAIN OUTCOME MEASURES

We evaluated auditory function by pure tone audiometry and speech discrimination score. Auditory evaluations were performed before and 3 months after treatment using Siegel's criteria. The degree of improvement in four-tone average hearing and speech discrimination score was calculated from the results before and after treatment.

RESULTS

The total hearing improvement rate after the treatment was 75.0% (90/120 patients) in this study. Although 47 patients (78.3%) of coenzyme Q10 group showed better hearing improvement than 43 patients (71.7%) of control group, there was no significant difference. However, the coenzyme Q10 group showed significantly higher improvement in speech discrimination score.

CONCLUSION

From this study, we suggest that coenzyme Q10 may have beneficial effects in the treatment of sudden sensorineural hearing loss.

Polarization orthogonalizer for a pair of laser beams with nearly equal frequencies

We have demonstrated a device to produce an overlapping pair of orthogonally polarized laser beams with a 3 GHz frequency offset out of a single laser beam containing the two frequency components with the same linear polarization. Our design is based on a Michelson interferometer formed by a polarizing beam splitter and two quarter-waveplates. Such a device can be used to make the polarization states of a carrier and a sideband produced through modulation mutually orthogonal. An orthogonally polarized pair of coherent laser beams can be used for an interferometric measurement of a small displacement in a heterodyne scheme or to produce a large-contrast coherent population trapping signal from alkali metal atoms. As a demonstration we used the device to achieve 40% contrast for a coherent population trapping signal from a rubidium vapor cell.

Sweep optical frequency synthesizer with a distributed-Bragg-reflector laser injection locked by a single component of an optical frequency comb

A sweep optical frequency synthesizer is demonstrated by using a frequency-stabilized optical frequency comb and injection-locked distributed-Bragg-reflector (DBR) laser diode. The injection-locked DBR laser acts as a single-frequency filter and, simultaneously, a high-gain amplifier of the optical frequency comb. The frequency instability of the heterodyne beat signal between two independently injection-locked DBR lasers is measured to be 2.3 x 10(-16) at 1 s averaging time. The output frequency of the sweep optical frequency synthesizer can be precisely tuned over 1 GHz, and a saturated absorption spectrum of the Cs D2 line at 852 nm is recorded by the injected DBR laser.

Lipo-prostaglandin E1 in combination with steroid therapy is effective for treatment of sudden sensorineural hearing loss in Korean patients with Type 2 diabetes

BACKGROUND

Diabetes mellitus is a risk factor for sudden sensorineural hearing loss (SSNHL), possibly as a result of microvascular damage, increased blood viscosity and embolic and thrombotic episodes. Aim To perform a prospective, randomized clinical trial to determine the therapeutic effect of lipo-prostaglandin E(1) (lipo-PGE(1)) on SSNHL in Korean patients with Type 2 diabetes.

METHODS

The study group consisted of 270 consecutive Korean patients (130 male, 140 female) in whom SSNHL was diagnosed. Patients were classified as diabetic or non-diabetic by the new American Diabetes Association criteria. With the approval of the institute ethics committee, patients were randomly assigned to treatment with of 10 microg lipo-PGE(1) (lipo-PGE(1) group) given as a continuous infusion over 5 days, or saline (placebo group). In addition, all patients studied were treated with 48 mg methylprednisolone for 5 days.

RESULTS

The overall recovery rates after treatment were 51.5% in diabetic and 64.2% in non-diabetic patients. In diabetic patients, there was a significantly higher rate of hearing improvement in the lipo-PGE(1) group (64.7%) compared with the placebo group (37.5%), whereas, in non-diabetic patients, there was no significant difference in rate of hearing improvement between the lipo-PGE(1) group (70.3%) and the placebo group (58.3%).

CONCLUSION

Lipo-PGE(1) may have beneficial effects in the treatment of SSNHL in Korean patients with Type 2 diabetes.

The relationship between body mass index and the prevalence of obesity-related diseases based on the 1995 National Health Interview Survey in Korea

This study estimated the body mass index (BMI) distribution of Koreans and examined the relationship between BMI and obesity-related diseases, in particular hypertension and diabetes mellitus. We also attempted to provide primary data to determine suitable BMI cut-off points for obesity in Korea. The 1995 National Health Interview Study (NHIS) data were used to estimate BMI and the prevalence of hypertension and diabetes mellitus. A random sample of 5750 Koreans (15-69 years of age) were investigated. BMI was calculated by self-reported weights and heights. The diagnoses of hypertension and diabetes mellitus were obtained from self-reported conditions specified in response to consultations with physicians. The mean BMI was 22.6+/-2.6 kg m(-2) for males and 21.7+/-4.8 kg m(-2) for females. The prevalence of hypertension and diabetes mellitus increased with BMI. The odds ratios of the third quartile of BMI (21.9-23.8 kg m(-2)) for hypertension and diabetes mellitus compared with the first quartile were 6.04 and 3.22, respectively. The odds ratio of the fourth quartile (>23.8 kg m(-2)) of BMI was not significantly different from that of the third quartile. The risk of hypertension and diabetes mellitus increased at the third quartile of BMI (21.9-23.8 kg m(-2)), this quartile being much lower than both the current World Health Organization (WHO) BMI cut-off point of overweight of 25.0 kg m(-2), and the 90th percentile proposed in the Monica project, BMI 26.4 kg m(-2). This finding was notable considering the fact that both hypertension and diabetes mellitus occur in Koreans with lower BMIs than whites. Further studies are necessary to identify the BMI cut-off point for obesity in Korea.

Inhibition of cholesteatomatous bone resorption with pamidronate disodium

Bone destruction is known to be an important cause of complications in chronic cholesteatomatous otitis media. A strategy that blocks localized bone resorption may prevent the progression of the disease. The bisphosphonate drug pamidronate is known to inhibit bone resorption and has been used in the treatment of Paget's disease and osteoporosis. The aim of this study was to investigate the effect of pamidronate on the inhibition of bone resorption in cholesteatoma using a neonatal rat calvarial culture system. Radioactive calcium was subcutaneously injected into pregnant rats. Neonatal calvariae were harvested after i.p. injection of pamidronate disodium to neonatal rats and culture supernatants of cholesteatoma keratinocytes were then added to the calvarial culture media. Radioactive calcium release was measured using a beta-ray scintillation counter. The percentage of calcium release was significantly higher in cholesteatoma culture supernatant than in Dulbecco's modification of Eagle's medium. The percentage calcium release in cholesteatoma culture supernatant was significantly lower with the high dose of pamidronate than with the low dose. These results suggest that pamidronate can inhibit the bone resorption caused by cholesteatoma. This study suggests a possible application for pamidronate in the prevention of cholesteatomatous bone destruction.

Accuracy comparison of absolute optical frequency measurement between harmonic-generation synthesis and a frequency-division femtosecond comb

Using an iodine-stabilized He-Ne laser as a transfer oscillator, we compare absolute measurements of the optical frequency from a traditional frequency synthesis chain based on harmonic generation and from the frequency division technique of an ultrawide bandwidth femtosecond frequency comb. The agreement between these two measurements, both linked to the Cs standard, is 220+/-770 Hz, yielding a measurement accuracy of 1.6x10(-12). We report 473 612 353 604.8+/-1.2 kHz as a preliminary updated value of the absolute frequency of the " f" component for the He-Ne laser international standard at 633 nm.

Nontwist quarter-wave liquid-crystal cell for a high-contrast reflective display

We propose an optical configuration of a nontwist quarter-wave liquid-crystal cell for a high-contrast reflective display that can be applied to most nontwist display modes. By fabricating a homogeneous cell with the proposed configuration, we have demonstrated a high contrast ratio of 50:1 without using a wideband retardation film.

A micromachined silicon depth probe for multichannel neural recording

A process of making a new type of silicon depth-probe microelectrode array is described using a combination of plasma and wet etch. The plasma etch, which is done using a low temperature oxide (LTO) mask, enables probe thickness to be controlled over a range from 5 to 90 mu. Bending tests show that the probe's mechanical strength depends largely on shank thickness. More force can be applied to thicker shanks while thinner shanks are more flexible. One can then choose a thickness and corresponding mechanical strength using the process developed. The entire probe shaping process is performed only at low temperature, and thus is consistent with the standard CMOS fabrication. Using the probe in recording from rat's somatosensory cortex, we obtained four channel simultaneous recordings which showed clear independence among channels with a signal-to-noise ratio performance comparable with that obtained using other devices.

Salivary gland choristoma of the middle ear: a case report

A choristoma is a nonneoplastic proliferation of histologically normal tissue that forms at an abnormal site. It is extremely uncommon in the middle ear space. It appears to be a developmental abnormality and may be associated with abnormalities of adjacent structures. It usually occurs with unilateral conductive hearing loss and requires a differential diagnosis from other mass lesions in the middle ear cavity. This article discusses a case of salivary gland choristoma of the middle ear that we believe to be the 24th case reported on this subject.

Unidirectional single-mode Nd:YAG laser with a planar semimonolithic ring cavity

Unidirectional single-mode operation of a diode-pumped Nd:YAG laser with a planar semimonolithic ring cavity has been demonstrated at 1064 nm. The semimonolithic cavity consists of a laser active medium placed in a magnetic field, a crystal quartz plate, and an output coupling mirror, which form an optical diode by acting as a Faraday rotator, a reciprocal polarization rotator, and a partial polarizer, respectively. A single-mode output power of 155 mW and a slope efficiency of 17% were obtained with a 1.2-W diode laser at 809 nm. A laser linewidth of less than 100 kHz is inferred from a beat note frequency spectrum between two identical laser systems and continuous tuning to greater than 2 GHz was observed.

Diffractometric methods for absolute measurement of diffraction-grating spacings

We propose one- and two-wavelength methods of absolute measurement of diffraction-grating spacings based on the Littman configuration for autocollimation. The one-wavelength method has been applied to measure the spacing of a grating with a nominal value of 2160grooves/mm . The grating spacing was measured to be 463.16 nm, with an experimental standard deviation of 0.24 nm. It has been demonstrated that the both methods can provide direct traceability in the submicrometer region in terms of wavelength standards for applications in the field of nanometrology.

Different production of interleukin-1alpha, interleukin-1beta and interleukin-8 from cholesteatomatous and normal epithelium

Cholesteatomatous bone destruction is caused by an increase in collagenase activity and activation of the osteoclasts. Cytokines. such as interleukins (IL), are important in intercellular communication in the mechanism of bone destruction. Middle ear cholesteatomas and external auditory canal skins (EACS) can be surgically obtained and cultured. The quantities of IL-1alpha, IL-1beta and IL-8 secretions were measured in the supernatant of each culture series. On the 2nd day of culture, the level of IL-1alpha was 0.60+/-0.13 (pg/microg of total protein) in cholesteatoma, and 0.25+/-0.02 in EACS. The levels of IL-1beta in cholesteatoma and EACS were 0.41+/-0.06 and 0.24+/-0.02, respectively. The levels of IL-8 in cholesteatoma and EACS were 146.50+/-32.37 and 50.40+/-6.24, respectively. After 2 days, the levels of IL-1alpha and IL-8 of each tissue decreased. The value from fibroblasts did not show a significant difference between cholesteatoma and EACS, and the values did not change as time passed. We can conclude that the IL-1alpha and IL-8 from the cholesteatomatous epithelium are responsible for the cholesteatomatous bone destruction and certain substances from the subepithelial granulation tissue can stimulate the cholesteatoma to produce IL-1alpha and IL-8.

Clinical experience with transurethral microwave thermotherapy for chronic nonbacterial prostatitis and prostatodynia

Chronic prostatitis and prostatodynia are troublesome disorders that are not responsive to any kind of treatment. Patients with treatment-resistant chronic nonbacterial prostatitis (n = 61) or prostatodynia (n = 17) for longer than 3 years underwent a single 1-hour session of transurethral microwave thermotherapy (TUMT) using the Prostatron. Complete symptom disappearance was obtained in 23% of patients and a partial response in 43%. Of the patients with prostatitis, 46% showed normalization and 31% an improvement of the leukocyte count in expressed prostatic secretion. In patients with prostatodynia, the corresponding figures were 35% and 41%. Most complications were temporary, but there was one case of epididymitis and one of reduction in the volume of the ejaculate. TUMT is well tolerated and safe, and it is effective in relieving the symptoms of many patients with nonbacterial prostatitis or prostatodynia. The possible adverse effects on fertility and urinary continence require further study.

Symptomatic versus asymptomatic endolymphatic hydrops: a histopathologic comparison

One of the unanswered questions in Meniere's disease research is the pathophysiology by which the classic symptoms are produced. A histopathological study was undertaken to identify the pathological features of symptomatic endolymphatic hydrops and their relationship to these symptoms. Two groups of temporal bones were examined, compared, and described. The first group was from patients with symptoms of Meniere's disease (n = 29). Temporal bones in the second group were chosen for the presence of endolymphatic hydrops and the absence of otologic symptoms (n = 13). Significant differences were noted in the severity of hydrops, the frequency of membrane ruptures, the endolymphatic duct, and coexistent pathologic conditions. Ruptures were seen in 38% of temporal bones from symptomatic patients and in only 8% of temporal bones from patients with asymptomatic endolymphatic hydrops. Based on this study and a review of the literature, the authors believe that the symptoms and findings of Meniere's disease are explained best on the basis of both chemical and physical mechanisms being operational intermittently and together.

Temporal bone histopathology in chronically infected ears with intact and perforated tympanic membranes

Chronic suppurative otitis media has been clinically defined as a chronic discharge from the middle ear in the presence of a perforation of the tympanic membrane. However, irreversible tissue pathology in the middle ear or mastoid can occur behind an intact tympanic membrane. One hundred forty-four human temporal bones with chronic otitis media were divided into two groups: those with perforated (28) and those with nonperforated (116) tympanic membranes. The histopathological findings of their middle ears were compared. Granulation tissue in various degrees was the most prominent pathological feature. It was observed in 96% of temporal bones with perforation of the tympanic membrane, and in 97% of those without perforation. Also found were ossicular bony changes (96% with perforation; 90.5% without), middle ear effusion (93% with perforation; 89% without), cholesterol granuloma (21% with perforation; 12% without), cholesteatoma (36% with perforation; 4% without), and tympanosclerosis (43% with perforation; 20% without). This study shows that the histopathological changes of the middle ear are similar in temporal bones with and without perforation of the tympanic membrane. The clinician should, therefore, be aware that an intact tympanic membrane does not necessarily preclude the presence of gross pathological changes of the middle ear cleft.

Pathology of labyrinthine ossification

Ossification of the inner ear is the result of multifactorial pathogeneses, such as infection or malignant infiltration, and otosclerosis. Ossification of the inner ear spaces is a well documented sequela of suppurative labyrinthitis. In this study of human temporal bones, sections from 14 patients (28 temporal bones) were studied. In addition to the osseous tissue within the inner ear, findings included neoplasms, otosclerosis, otitis media, trauma, and Fabry's disease. We have attempted to correlate these conditions and their influence on the formation of osseous tissue within the spaces of the inner ear. Tympanogenic infection and vascular compromise were found to play an important role in ossification. The scala tympani of the basal turn of the cochlea was frequently the site involved.

Age-related morphologic changes in the human tympanic membrane. A light and electron microscopic study

To our knowledge, the normal changes that occur in the tympanic membrane after birth have not been described, despite several reports that their otoscopic appearance in healthy, full-term infants is different from that in adults. To provide such a description, the tympanic membranes of 54 temporal bones that had no pathologic evidence of otologic diseases, from patients aged 33 weeks' gestation to 91 years, were examined with light or electron microscopy. The changes encountered in thickness, cellularity, vascularity, collagen, and elastin indicated beyond the first year of life and into old age.

Cellular changes in Reissner's membrane in endolymphatic hydrops

A quantitative morphologic study of the cellular changes in human Reissner's membrane (RM) was performed under light microscopy on 30 normal temporal bones from 15 subjects, and on 20 temporal bones from 10 subjects with endolymphatic hydrops. The cellular density of the epithelial and mesothelial layers of normal RMs decreased with increasing age. In endolymphatic hydrops, cellular proliferation and decreased cellular density of a distended RM were observed, and these changes occurred more remarkably in epithelial cells. Decreased cellular density in RM was correlated to the degree of endolymphatic hydrops. These findings indicate an involvement of the epithelial cellular changes in the pathogenesis of endolymphatic hydrops. Our results suggest that cellular changes in RM may cause dysfunction of radial flow leading to ionic disturbance of endolymph, which provides a possible mechanism of hearing loss in endolymphatic hydrops.

The enhanced cellular uptake of very-low-density lipoprotein enriched in apolipoprotein E

We have recently reported an increased clearance of plasma very-low-density lipoprotein (VLDL) after intravenous injection of apolipoprotein (apo) E in Watanabe heritable hyperlipidemic (WHHL) rabbits. In the present study, we have investigated the cellular uptake of VLDL enriched in apo E (VLDL-E) which had been incubated with purified rabbit apo E. VLDL-E was taken up approx. 2-fold more than VLDL in human skin fibroblast, human monocyte-derived macrophage and Hep G2 cell and its degradation was least in macrophage. To characterize the binding of VLDL-E, we performed a binding assay using hepatic endosome isolated from estradiol-treated rats and we observed both increased EDTA-sensitive and -resistant binding of VLDL-E on endosome. Ligand blotting of hepatic endosome demonstrated two major bands of LDL receptor (130 and 260 kDa protein) and a minor band of LDL receptor-related protein (580 kDa protein) with a ligand of VLDL-E. These results suggested that VLDL-E was endocytosed in liver through a similar pathway among three cell types, and enrichment of apo E in VLDL enhanced the uptake of VLDL not only via an EDTA-sensitive binding site (classical LDL receptor) but also via other binding sites including an EDTA-resistant binding site and an LDL receptor-related protein.

Characterization of monoclonal anti-rabbit apolipoprotein E antibodies and chemical composition of lipoproteins separated by anti-apolipoprotein E immuno-affinity chromatography

Six mouse monoclonal antibodies against rabbit apolipoprotein E (apo E) have been developed. Of these monoclonal antibodies, clone 5 revealed a high affinity for purified apo E, very low density lipoprotein (VLDL) and beta-VLDL. This monoclonal antibody was used to prepare an immunoaffinity column. Coupled to Sepharose 4B, this antibody allowed complete removal of lipoproteins containing apo E from plasma of New Zealand white (NZW) rabbits; 62, 46, 14, and 3% of VLDL-, IDL-, LDL-, and HDL-protein, respectively, were bound to the anti-apo E affinity column. The bound VLDL was significantly rich in free cholesterol (FC) and cholesteryl esters (CE) relative to the unbound VLDL, whereas bound IDL, LDL and HDL were significantly rich in FC only. All of the bound fractions were characterized by significantly increased ratios of FC/phospholipids (PL). These results indicate that the two lipoprotein populations with and without apo E have different lipid compositions. The relatively high content of cholesterol in lipoproteins containing apo E suggests a contribution of apo E to plasma cholesterol transport.

Histopathology of the tensor tympani muscle in otitis media

Involvement of the tensor tympani muscle (TTM) and tendon in otitis media have been suggested both clinically and experimentally. Extensive postmortem histopathological studies of the human TTM in cases with known otitis media have not been done. One-hundred-five human temporal bones with and without otitis media were evaluated using light microscopy to determine the pathological changes of the TTM and tendon. Fatty cell infiltration and degenerative changes of the muscle fibers were observed in non-otitis and otitis media groups, but were greater in those cases with otitis media. Inflammatory cell infiltration and fibroblastic reactions occurred more often in chronic and purulent otitis media, and hypercontracted fibers were more frequent in serous and chronic otitis media. This study indicates that the human TTM and tendon are pathologically involved in the inflammatory process of otitis media.

Histopathology of sudden hearing loss

Eleven temporal bones from eight patients who had clinical histories of sudden hearing loss (SHL) were studied to assess the possible etiopathogenesis. The origin of SHL in seven ears from five patients was obscure, but appeared to be due to multiple causes. Common histopathologic changes in the cochlea, although complex, included atrophy of the organ of Corti and loss of cochlear neurons. Loss of cochlear neurons was the main finding in ears of viral infection. Labyrinthine fibrosis and formation of new bone were seen in two ears associated with vascular insult and in two ears of autoimmune disease. Different histopathologic findings causing SHL were observed even in cases with the same etiology. A case of SHL showing endolymphatic hydrops as the main histopathologic finding is described.

Otosclerosis involving the vestibular aqueduct and Menière's disease

The coexistence of otosclerosis and endolymphatic hydrops in the temporal bone have been described; however, the mechanism for the development of endolymphatic hydrops in otosclerosis remains unknown. Among 128 temporal bones with otosclerosis, involvement of the vestibular aqueduct by otosclerosis was observed in four temporal bones from two patients. In all four, the vestibular aqueduct was filled with active otosclerotic foci; the lumen of the endolymphatic duct and sac was narrowed as a result of fibrosis, and endolymphatic hydrops, more severe in the pars inferior than the pars superior, was observed. Collapse of the ductus reuniens and dilated saccule was seen in three temporal bones. Our study indicates that otosclerotic obstruction of the vestibular aqueduct may create a disturbance of the outflow and/or absorption of endolymph, leading to the development of endolymphatic hydrops and Meniere's disease, thus supporting the theory of longitudinal flow of endolymph.

Morphometric studies of the continuum of otitis media

Morphometric changes in the epithelium and subepithelium of the middle ear mucosa from children younger than 10 years of age were measured at the promontory in 85 temporal bones with otitis media and in 29 normal temporal bones by use of quantitative and semiquantitative methods. Comparisons of morphologic analysis in different otitis media types showed that acute inflammatory changes were usually seen in purulent otitis media with effusion and serous otitis media with effusion, and chronic inflammatory changes were more severe in mucoid otitis media with effusion and chronic otitis media. There were overlaps, however, in histopathologic findings between different types of otitis media that suggest a continuum of otitis media types, with one type of otitis media changing into another type.

Otopathologic correlates of the continuum of otitis media

It has been our hypothesis that different types of middle ear effusions and the clinical manifestations with which they are associated represent the typical inflammatory response. Employing an animal model under controlled conditions, we present statistical evidence that change in the mucosa of the middle ear in otitis media can occur along a continuum, with early forms regressing to more chronic stages of the disease. We also demonstrate an increase in the thickness and a decrease in the permeability of the round window membrane in a longitudinal study of otitis media in the same animal model. Histopathologic changes in human temporal bones with otitis media with effusion or chronic otitis media are similar to the changes in the animal models. These results support a concept that all categories of otitis media (serous, purulent, mucoid, and chronic) represent different stages in a continuum of events.

The release of hepatic triglyceride lipase from rat monolayered hepatocytes in primary culture

The release of hepatic triglyceride lipase from cultured rat hepatocytes and its hormonal regulation were studied. The activity of lipase released into the medium in the presence of heparin was increasing for 24 hours on the 2nd day of culture. The activity in the absence of heparin was only 10% of that in the presence of heparin. When hepatocytes were cultured with anti-hepatic triglyceride lipase IgG, the lipase activity was suppressed by 92%. The results suggest that the enzyme released into the culture medium is identical to hepatic triglyceride lipase which can be released only in the presence of heparin, the mode of release being similar to that of lipoprotein lipase from adipocytes. The addition of colchicine and monensin to the medium resulted in the inhibition of lipase secretion by 20% and 61%, respectively. Insulin enhanced lipase activity only 20%, whereas dexamethasone suppressed the activity by 44%. These data indicated that hepatic triglyceride lipase is secreted and released from hepatocytes in the presence of heparin and its secretion is regulated by hormones.

Pathology and pathogenesis of tympanic membrane retraction

Temporal bones without evidence of otitis media, as well as temporal bones with various types of otitis media, were examined for the presence of retractions of the tympanic membrane and their related histopathologic progression to the formation of cholesteatoma. Retractions were not present in non-otitis media, purulent, or mucoid otitis media. Retractions were observed in 2.1% of temporal bones with serous otitis media and 19.5% of temporal bones with chronic otitis media. All temporal bones with retractions demonstrated evidence of current or previous otitis media. Histopathologic changes of the middle ear cleft were associated with the type and degree of retraction. This study supports the continuum theory according to which otitis media with effusion eventually leads to a variety of sequelae and/or to chronic otitis media. The tympanic membrane appears to follow progressive changes, from simple retraction to retraction pockets and finally to cholesteatoma.

Congenital cholesteatomas of the cerebellopontine angle

Thirty cases of congenital cholesteatomas of the cerebellopontine angle (CPA) treated over a period of 20 years are reviewed with regard to their clinical features, the pathophysiology of their symptoms, and their management. The predominant symptoms were related to cranial nerves VII and VIII and headaches. Signs and symptoms were divided into those caused by local involvement of the cholesteatoma, increased intracranial pressure, or both. Diagnostic procedures from invasive procedures such as ventriculography to more sophisticated noninvasive procedures including computed tomography and magnetic resonance imaging are discussed. The surgical management of 27 congenital cholesteatomas was accomplished via a posterior cranial fossa approach. Total excision of the cholesteatoma was the aim but was carried out in only five (18%) patients because of concern regarding the preservation of nearby neurovascular structures. Partial excision was possible in 22 (82%) patients. To minimize re-formation, the residual cholesteatoma was carefully cauterized with the aid of the operating microscope and bipolar diathermy without damaging surrounding neurovascular structures. Follow-up has ranged from 2 to 15 years, with four (13%) cases of re-formation.