Localization and proteomic characterization of cholesterol-rich membrane microdomains in the inner ear

Biological membranes organize and compartmentalize cell signaling into discrete microdomains, a process that often involves stable, cholesterol-rich platforms that facilitate protein-protein interactions. Polarized cells with distinct apical and basolateral cell processes rely on such compartmentalization to maintain proper function. In the cochlea, a variety of highly polarized sensory and non-sensory cells are responsible for the early stages of sound processing in the ear, yet little is known about the mechanisms that traffic and organize signaling complexes within these cells. We sought to determine the prevalence, localization, and protein composition of cholesterol-rich lipid microdomains in the cochlea. Lipid raft components, including the scaffolding protein caveolin and the ganglioside GM1, were found in sensory, neural, and glial cells. Mass spectrometry of detergent-resistant membrane (DRM) fractions revealed over 600 putative raft proteins associated with subcellular localization, trafficking, and metabolism. Among the DRM constituents were several proteins involved in human forms of deafness including those involved in ion homeostasis, such as the potassium channel KCNQ1, the co-transporter SLC12A2, and gap junction proteins GJA1 and GJB6. The presence of caveolin in the cochlea and the abundance of proteins in cholesterol-rich DRM suggest that lipid microdomains play a significant role in cochlear physiology.

BIOLOGICAL SIGNIFICANCE

Although mechanisms underlying cholesterol synthesis, homeostasis, and compartmentalization in the ear are poorly understood, there are several lines of evidence indicating that cholesterol is a key modulator of cochlear function. Depletion of cholesterol in mature sensory cells alters calcium signaling, changes excitability during development, and affects the biomechanical processes in outer hair cells that are responsible for hearing acuity. More recently, we have established that the cholesterol-modulator beta-cyclodextrin is capable of inducing significant and permanent hearing loss when delivered subcutaneously at high doses. We hypothesize that proteins involved in cochlear homeostasis and otopathology are partitioned into cholesterol-rich domains. The results of a large-scale proteomic analysis point to metabolic processes, scaffolding/trafficking, and ion homeostasis as particularly associated with cholesterol microdomains. These data offer insight into the proteins and protein families that may underlie cholesterol-mediated effects in sensory cell excitability and cyclodextrin ototoxicity.

Cushing's Syndrome: An Unusual Presentation of Olfactory Neuroblastoma

A 48-year-old man presented with symptoms consistent with Cushing's syndrome. Subsequent laboratory studies revealed markedly elevated adrenocorticotropic (ACTH) and cortisol levels, as well as a hypoklemic metabolic alkalosis. A pituitary MRI was performed, which revealed a normal pituitary; however, a large mass was seen centered in the ethmoid and paranasal sinuses with a significant amount of extension into surrounding structures. A biopsy was performed and pathology of the specimen was consistent with esthesioneuroblastoma. Immunohistochemical staining further defined the tumor as an ACTH-secreting esthesioneuroblastoma. After total resection of the mass and further treatment with adjuvant radiation therapy, the patient's symtoms completely resolved and the ACTH and cortisol levels were also greatly reduced. This case demonstrates the successful diagnosis and treatment of a rare neoplasm. Ectopic ACTH syndrome due to esthesioneuroblastoma is extremely uncommon with only five other cases being discussed in the literature.

The seductive superego: the trauma of self-betrayal

The author describes a pathological manifestation of the approving superego that functions as a perversely seductive superego. In this process, the seductive superego rationalises and makes ego-syntonic a gratification of forbidden wishes that will result in unconscious punishment. The author argues that the seductive superego torments the self by teasing it with the presence of a tantalising but forbidden object of desire and then by inflicting shame on the self for its timidity, which prevents it from pursuing the object in spite of the dangers. He suggests that the seductive superego inflicts a betrayal trauma upon the self by unconsciously actualising a sado-masochistic fantasy of seduction, surrender and betrayal, along with a humiliating punishment for surrendering.

Personal exposure to nitrogen dioxide and risk of airflow obstruction in asthmatic children with upper respiratory infection

BACKGROUND

Several studies have linked air pollution by nitrogen dioxide (NO(2)) with increased hospital admissions for asthma in children. Exacerbations of asthma in children are often precipitated by upper respiratory infections. It is therefore possible that NO(2) increases the risk of airways obstruction when asthmatic children develop upper respiratory infections.

METHODS

To test this hypothesis a sample of 114 asthmatic children aged 7-12 years were followed for a total of up to 13 months. Probable upper respiratory infections were identified by consensus review of daily symptom diaries, and episodes of airways obstruction from serial records of peak expiratory flow (PEF). Personal exposures to NO(2) were measured with Palmes tubes that were changed weekly. Generalised estimating equations were used to assess the relative risk (RR) of an asthmatic exacerbation starting within seven days of an upper respiratory infection according to estimated NO(2) exposure during the one week period from two days before to four days after the onset of the infection.

RESULTS

The children were followed for an average of 34 weeks during which 318 upper respiratory infections and 224 episodes of reduced PEF were diagnosed. PEF episodes were much more likely to occur in the seven days following the onset of an upper respiratory infection than at other times. Estimated exposures to NO(2) at the time of infections were generally low (geometric mean 10.6 microg/m(3)). Compared with exposures of < or = 8 microg/m(3), exposures of >28 microg/m(3) were associated with a RR of 1.9 (95% confidence interval 1.1 to 3.4) for the development of an asthmatic episode within seven days of an infection.

CONCLUSIONS

The findings give some support to the hypothesis that NO(2) increases the risk of asthmatic exacerbations following respiratory infections, even at relatively low levels of exposure. Further studies in populations with higher exposures would be useful.

Self-criticism and the psychic surface

It is postulated that the surface of the mind reflects a variety of shifting self-syntonic and self-dystonic contents striving to achieve a stable homeostatic balance. Shifts between self-syntonic and self-dystonic contents are seen to reflect an underlying intrasystemic conflict within the superego between conflicting superego injunctions. These shifts possess a cyclical quality, as self-syntonic contents become self-dystonic and as self-dystonic contents become self-systonic. This conceptualization of the psychic surface has implications for a comparative study of psychoanalytic technique and for implementing the technical recommendation to work from surface to depth. It is suggested that the analyst's interpretations become assimilated within cyclical processes of superego reaction and repair.

The view from the tip of the iceberg

In recent years there has been a growing interest in refining the technique of ego defense analysis. All of these approaches share in common an attempt to work closely with the patient's free associations, to interpret at a level that is accessible to the patient's consciously observing ego, and to avoid bypassing the analysis of the patient's most surface-level resistances in an effort to understand unconscious conflict. These innovations reflect a commendable effort to work in a way that is rigorously empirical, that respects the patient's autonomy, and that minimizes the pressure of the analyst's transferential authority in the patient's acceptance of the analyst's interpretations. Despite the undeniable value of these technical innovations, such approaches to ego defense analysis may inadvertently result in certain overemphases in technique that may unnecessarily constrain the analytic process. They may result in a sort of obsessive tunnel vision that is overly focused on small details to the exclusion of the larger picture. An approach that counterbalances the microscopic and the macroscopic analysis of ego defense is recommended.

Community study of role of viral infections in exacerbations of asthma in 9-11 year old children

OBJECTIVE

To study the association between upper and lower respiratory viral infections and acute exacerbations of asthma in schoolchildren in the community.

DESIGN

Community based 13 month longitudinal study using diary card respiratory symptom and peak expiratory flow monitoring to allow early sampling for viruses.

SUBJECTS

108 Children aged 9-11 years who had reported wheeze or cough, or both, in a questionnaire.

SETTING

Southampton and surrounding community.

MAIN OUTCOME MEASURES

Upper and lower respiratory viral infections detected by polymerase chain reaction or conventional methods, reported exacerbations of asthma, computer identified episodes of respiratory tract symptoms or peak flow reductions.

RESULTS

Viruses were detected in 80% of reported episodes of reduced peak expiratory flow, 80% of reported episodes of wheeze, and in 85% of reported episodes of upper respiratory symptoms, cough, wheeze, and a fall in peak expiratory flow. The median duration of reported falls in peak expiratory flow was 14 days, and the median maximum fall in peak expiratory flow was 81 l/min. The most commonly identified virus type was rhinovirus.

CONCLUSIONS

This study supports the hypothesis that upper respiratory viral infections are associated with 80-85% of asthma exacerbations in school age children.

The Freudian superego

Beginning psychotherapists tend to judge themselves in terms of their Freudian superego, their idea of how a stereotypical classical analyst is supposed to work. This Freudian superego derives from culturally prevalent negative stereotypes about the nature of Freudian psychoanalysis.