The Aging Cochlear Hair Cell

Specimens from the organ of Corti were taken from regions which appeared normal in the cytocochleogram as evaluated with the Nomarski optics. Ultrastructural, qualitative analyses of aging cochlear hair cells in the guinea pig showed, however, principally five distinct types of pathological changes: (1) disintegration of the cuticle; (2) increased amounts of intracellular lamellar structures and submembrane cisternae; (3) aggregations of electron optically dense particles; (4) lysosome-like structures; and (5) vesiculation of cytoplasm. Stereocilia remained intact also in cells where the cuticular plate showed severe degeneration. Outer hair cells showed more extensive cytological changes than inner hair cells. The ultrastructural pathology in aging cochlear hair cells is specific and is a sign of dysdifferentiation of their specific morphology although the hair cells survive for a long time in a more or less dysdifferentiated state. Hair cell changes were primary, leaving afferent and efferent nerve terminals initially morphologically intact

PERMAINAN TRADISIONAL ANAK NAGARI DALAM FOTOGRAFI KONSEPTUAL

Permainan tradisional adalah permainan yang dimiliki oleh suatu kelompok masyarakat yang diwariskan dari satu generasi ke generasi berikutnya. Fotografi dimanfaatkan untuk mengingatkan kembali permainan tradisional yang sudah mulai ditinggalkan. Flashback diartikan sebagai kenangan, dimana dalam karya foto ini penulis mencoba menghadirkan kembali tentang kenangan dari permainan tradisional anak yang pernah penulis mainkan dahulu, dan pernah dirasakan penulis . Konsep kenangan masa lalu ini divisualkan penulis dengan cara menggunakan teknik pengambilan e ye level dan teknik lighting side light . Pena ulismenjadikan fotografi sebagai media untuk menghadirkan kembali kenangan dan bentuk permainan tradisional itu sendiri , t erutama dalam konteks fotografi . Penulis menceritakan pengalaman saat bermain di waktu kecil itu sendiri dari hal yang terdengar sederhana, tetapi didalam ingatan ini terdapat kenangan dan bentuk permainan anak-anak yang saat ini sudah jarang ditemukan . Maka dari itu fotografi sangat berperan penting didalam karya ini, karena dengan sebuah foto seseorang dapat menyampaikan apa yang dirasakan melalui karya foto. Tugas akhir ini berupa fotografi kontekstual yang mengangkat tema tentang flashback penulisdan bentuk dari permainan tradisional anak, yang sudah lama tersimpan dalam ingatan. Proses penciptaan karya ini dilakukan dengan empat tahapan sebagai proses penciptaan karya yaitu persiapan, perancangan, perwujudan dan penyajian karya. Keseluruhan permainan anak dalam memori penulis ini akan di aplikasikan dalam bentuk foto warna hangat membuat suasana karya foto dibawa kedalam masa lalu penulis

Freeze-Drying and Related Preparation Techniques for Biological Microprobe Analysis

An X-ray microanalytical and morphological investigation has been carried out on rapidly frozen, freeze-dried or freeze-substituted tissues. A comparison was made between different embedding and polymerisation procedures following freeze-substitution and freeze-drying. The investigation also included an analysis of specimens infiltrated, embedded and polymerised by ultraviolet irradiation at low temperatures with Lowicryl HM20. The morphological preservation of Lowicryl embedded tissue was adequate for the identification of different cell structures like nuclei, mitochondria, lysosomes and different types of endoplasmic reticulum. X-ray microanalytical investigation of low temperature embedded material displayed an elemental composition of cells and organelles similar to that found in freeze-dried cyosections. Compared with freeze-dried cryosections, low temperature embedded material could be sectioned for light microscopy and area of interest chosen for further thin sectioning. This is of great importance in work with tissues with complicated morphology and heterogenous cell populations

Applications of Scanning Electron Microscopy and X-Ray Microanalysis in Inner Ear Pathology

Surface pathology of inner ear structures so far described in detail concern cochlear and vestibular hair cells and the stria vascularis. In man, surgical intervention into the inner ear is very uncommon and when performed is in general with the primary objective of destroying the diseased peripheral end organs. The vast majority of inner ear tissue available for use with scanning electron microscopy (SEM) is therefore obtained from animals. The present paper reviews the progression of surface pathology caused by aminoglycoside antibiotics, acoustic overstimulation and in a guinea pig strain with genetic inner ear disease. The primary site of onset of surface pathology differs, depending on the underlying cause. Advanced surface pathology shows a similar type of morphological degeneration independent of cause. The combination of SEM and energy dispersive X-ray microanalysis (XRMA) of inner ear pathology has as yet been reported in only three studies, all concerning inner ear fluids or otoconia

Longitudinal links between adolescent social anxiety and depressive symptoms: stressful experiences at home, in school and with peers

Social anxiety and depressive symptoms often co-occur during early adolescence but contributing factors to this development are still a matter of debate. This study examined the role of daily stressors (peers, school and homelife) in the links between adolescent social anxiety and depressive symptoms. 7-8th graders at Time 1 (N = 2,752, Mage = 13.65; 47.5% girls) were followed across three time-points. Cross-lagged path models showed that depressive symptoms predicted later social anxiety, but not vice versa. Bidirectional links were identified between peer stress and social anxiety, and between school/homelife stress and depressive symptoms, respectively. Indirect effects of social anxiety, depressive symptoms, and daily stressors were found, though stressors did not mediate the links between social anxiety and depressive symptoms (or vice versa). Our findings indicate an intricate role of daily stressors in different domains on the links between social anxiety and depressive symptoms

A Low Temperature Vacuum Embedding Procedure for X-Ray Microanalysis of Biological Specimens at Subcellular Level

The validity of freeze-drying and low temperature embedding in Lowicryl resins has been investigated in studies of ion distribution in mouse embryological inner ear, rat rib growth plate, liver and submandibular gland. The morphological preservation of the tissues was adequate for the identification of different intracellular compartments and extracellular structures. It was also possible to analyze extracellular fluids in the vestibular part of the developing inner ear. Compared with thin cryosections, Lowicryl sections are easier to produce and are more stable during analysis. Freeze-dried embedded material can be easily reorientated during cutting and adjacent sections can be used for other purposes such as histochemical and morphological investigations. We found that hydrophilic Lowicryl K11M, which is normally used for immunocytochemical investigations, also can be used for microanalysis. That opens the possibility for combined immunocytochemical and microanalytical studies. However, infiltration and polymerization steps have to be carried out at slightly higher temperatures than when the hydrophobic Lowicryl HM23 is used

Cellular localization of adenylate cyclase in the developing and mature inner ear of the mouse

The localization of adenylate cyclase in the developing and mature inner ear of the CBA/CBA mouse, in Shaker-1 and Shaker-2 mutants and in organ culture was determined by a histochemical procedure with adenylyl imidodiphosphate as substrate and Sr2+ as capture ion. Enzymatic activity was associated with cell membranes in stria vascularis and Reissner's membrane but could not be demonstrated in other cochlear structures. In stria vascularis, adenylate cyclase was found on the contraluminal infoldings of marginal cells but not on their luminal surface, while Reissner's membrane showed activity on its endolymphatic surface. Activity was also associated with utricular dark cells. Essentially the same localization but differing in quantitative aspects was observed during development, in organ culture and in the mutant strains. The speculative role of adenylate cyclase in cochlear ion and fluid balance is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25207/1/0000646.pd

Adenylate cyclase activity in the fetal and the early postnatal inner ear of the mouse

The adenylate cyclase activity was analyzed in fetal, early postnatal and adult inner ears of the CBA/CBA mouse and also in approximately one month old inner ears from Shaker -1 and Shaker -2 mice. A comparison was made with the maturation of potassium levels in endolymph as investigated with the X-ray energy dispersive technique.Adenylate cyclase activity in the developing normal inner ear shows two significant periods of increases: from the 16th to the 19th gestational day in both the cochlear and vestibular parts of the labyrinth, and from birth to day 6 after birth in the lateral wall tissues of the scala media. During the first period the anatomical boundaries of the secretory epithelia are developing. The postnatal rise in adenylate cyclase activity correlates with the morphological maturation of stria vascularis at the cellular and subcellular levels and the rise in potassium content of endolymph. The rise of enzyme activity in the cochlea during the maturation of endolymph supports a link between adenylate cyclase and the control of inner ear fluids. Adenylate cyclase activity in stria vascularis/spiral ligament of Shaker -1 and Shaker -2 mice were at normal levels and correlated better with the rather normal morphology of the tissues than the abnormal composition of endolymph in these mutants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24431/1/0000703.pd

Development of a Shortened Version of the Adolescent Stress Questionnaire (ASQ-S): construct validity and sex invariance in a large sample of Swedish adolescents

Background: Stressor experience is an important topic of research concerning adolescent health and ill-health. For this, valid and reliable measures of adolescent stress are needed. The Adolescent Stress Questionnaire 2 was developed to tap into stressor domains specific for adolescence. Psychometric evaluations in Australian and European samples have indicated adequate psychometric properties. However, the ASQ-2 is quite extensive, which may render its use in large cohort studies, where several aspects of adolescent health are investigated, inconvenient and problematic. Objective: To evaluate the psychometric properties of a short version of the ASQ-2 (ASQ-S) in terms of construct validity and factorial invariance across gender. Method: The ASQ-2 was translated into Swedish and items were retained from nine of the ten scales based on factor loadings. One scale (stress of emerging adult responsibilities) was removed entirely due to low internal consistency and variance explained. The remaining 27 items were piloted and then included in an ongoing 5-year longitudinal study involving the participation of all students in the 7th and 8th grade in public schools from three Swedish municipalities (N = 2768, 47.5 % girls, mean age 13.64 years). For this study data from the first and second wave was used. Results: A nine factor Confirmatory Factor Analysis (CFA) showed a good fit to the data and invariance across sexes was supported. The nine scales correlated positively with depressive symptoms, anxiety and worry and negatively with self-esteem. Girls reported higher stress levels than boys in eight of the nine scales. Stressors related to peer pressure predicted reported levels of anxiety and worry one year later, whereas stressors related to romantic relationships predicted depressive symptoms. Conclusions: Overall this study suggests that the ASQ-S could be a valid measure of adolescent stressor experience and psychometrically equivalent to the full ASQ-2.This research was supported by Forskningsrådet Formas, Forskningsrådet för Arbetsliv och Socialvetenskap (FAS), Vetenskapsrådet, and Vinnova

Otoconin-90 Deletion Leads to Imbalance but Normal Hearing: A Comparison with Other Otoconia Mutants

Our sense of gravitation and linear acceleration is mediated by stimulation of vestibular hair cells through displacement of otoconia in the utricle and saccule (the gravity receptor organ). We recently showed that otoconin-90 (Oc90) deletion led to formation of giant otoconia. In the present study, we determined the extent to which the giant otoconia affected balance and gravity receptor sensory input and compared the findings with other otoconia mutants. We employed a wide spectrum of balance behavioral tests, including reaching and air-righting reflexes, gait, swimming, beam-crossing, rotorod latencies, and a direct measure of gravity receptor input, vestibular evoked potentials (VsEPs). All tests on homozygous adult mutants consistently ranked the order of imbalance as (from worst to best) Nox3het<otopetrin 1tlt<Oc90 null<Oc90 wild type and C57Bl/6 mice using systematic statistical comparisons of the frequency of occurrence or the severity of abnormal functions. This order coincides with the degree of otoconia deficiencies and is consistent with VsEP measures. Notably, all mice (except Nox3het) showed remarkable learned adaptation to peripheral vestibular deficits by staying on the rotating rod significantly longer in each successive trial, and the rate and extent of such learned improvements ranked the same order as their initial balance ability. Despite the vestibular morbidity, Oc90 null mice had normal hearing, as measured by auditory brainstem responses (ABRs) and distortion products of otoacoustic emissions (DPOAEs). The study demonstrates that the remnant otoconia mass in Oc90 nulls does stimulate the gravity receptor organs, which was likely responsible for the improved balance performance relative to strains with absent otoconia. Furthermore, the combination of direct electrophysiological measures and a series of behavioral tests can be used to interpret the imbalance severity arising from altered inputs from the gravity receptor end organ. Originally published Neuroscience, Vol. 153, No. 1, Apr 200