Laser Doppler vibrometric assessment of middle ear motion in Thiel-embalmed heads

Thiel-embalmed human whole head specimens represent an alternative model in middle ear research.

Bone conduction in Thiel-embalmed cadaver heads

INTRODUCTION Sound can reach the inner ear via at least two different pathways: air conduction and bone conduction (BC). BC hearing is used clinically for diagnostic purposes and for BC hearing aids. Research on the motion of the human middle ear in response to BC stimulation is typically conducted using cadaver models. We evaluated middle ear motion of Thiel-embalmed whole-head specimens in terms of linearity, reproducibility, and consistency with the reported middle ear motion of living subjects, fresh cadaveric temporal bones, and whole-heads embalmed with a Non-Thiel solution of salts. METHODS We used laser Doppler vibrometry to measure the displacement of the skull, the umbo, the cochlear promontory, the stapes, and the round window in seven ears from four human whole-head specimens embalmed according to Thiel's method. The ears were stimulated with a Baha(®) implanted behind the auricle. RESULTS The Thiel model shows promontory velocity similar to that reported in the literature for whole-heads embalmed with a Non-Thiel solution of salts (0- to 7-dB difference). The Thiel heads' relative velocity of the stapes with respect to the promontory was similar to that of fresh cadaver temporal bones (0- to 4-dB difference). The velocity of the umbo was comparable in Thiel-embalmed heads and living subjects (0- to 10-dB difference). The skull and all middle ear elements measured responded linearly to different stimulation levels, with an average difference less than 1 dB. The variability of repeated measurements for both short- (2 h; 4 dB) and long-term (4-16 weeks; 6 dB) repetitions in the same ear, and the difference between the two ears of the same donor (approximately 10 dB) were lower than the inter-individual difference (up to 25 dB). CONCLUSION Thiel-embalmed human whole-head specimens can be used as an alternative model for the study of human middle ear mechanics secondary to BC stimulation. At some frequencies, differences from living subjects must be considered.

Bone conduction responses of middle ear structures in Thiel embalmed heads

Thiel-embalmed human whole-head specimens offer a promising alternative model for bone conduction (BC) studies of middle ear structures. In this work we present the Thiel model’s linearity and stability over time as well as its possible use in the study of a fixed ossicle chain. Using laser Doppler vibrometry (LDV), the motion of the retroauricular skull, the promontory, the stapes footplate and the round window (RW) were measured. A bone-anchored hearing aid stimulated the ears with step sinus tones logarithmically spread between 0.1 and 10 kHz. Linearity of the model was verified using input levels in steps of 10 dBV. The stability of the Thiel model over time was examined with measurements repeated after hours and weeks. The influence of a cement-fixed stapes was assessed. The middle ear elements measured responded linearly in amplitude for the applied input levels (100, 32.6, and 10 mV). The variability of measurements for both short- (2 h) and long-term (4-16 weeks) repetitions in the same ear was lower than the interindividual difference. The fixation of the stapes induced a lowered RW displacement for frequencies near 750 Hz (-4 dB) and an increased displacement for frequencies above 1 kHz (max. +3.7 dB at 4 kHz). LDV assessment of BC-induced middle ear motion in Thiel heads can be performed with stable results. The vibratory RW response is affected by the fixation of the stapes, indicating a measurable effect of ossicle chain inertia on BC response in Thiel embalmed heads.

Die Erdbeerkulturen des Herrn Thiel in Plötzensee

anonym

Lehrbuch der vergleichenden Entwicklungsgeschichte der wirbellosen Tiere : Specieller Thiel / von E. Korschelt und K. Heider.

pt. 3

Lehrbuch der vergleichenden Entwicklungsgeschichte der wirbellosen Tiere : Specieller Thiel / von E. Korschelt und K. Heider.

pt. 1

Lehrbuch der vergleichenden Entwicklungsgeschichte der wirbellosen Tiere : Specieller Thiel / von E. Korschelt und K. Heider.

pt. 2

Agencification in Latin countries: Portugal

This chapter provides a broad look at the Portuguese process of agencification in the last two decades. As with most of the remaining chapters in this book, we cover the basics by describing the administrative landscape, its changes in organizational make-up, the delicate balance between control and autonomy in the ministry-agency relationship, perceptual changes in efficiency and performance measurement in public management, based on a comprehensive survey (COBRA survey of the CRIPO research group) sent to all public-sector organizations under public law with some degree of autonomy (see Chapter 1, Table 1.1). Portugal is undergoing the most pervasive politico-economic crisis in its short democratic history. The administrative mapping conducted in 2007 which served as the basis for the administration of the COBRA survey is already undergoing change.

Adelic convex geometry of numbers

Magdeburg, Univ., Fak. für Mathematik, Diss., 2014

Filariopsis barretoi (Travassos, 1921) comb. n. parasito de "Mico-estrela", ocorrência e patogenia (Nematoda, Metastrongylidae)

O autor reestuda a espécie Filariopsis barretoi (Travassos, 1921) parasita de pulmões de Callithrix jacchus (mico-estrela). Trata-se da segunda observação destes parasitas. É feito um resumo histórico destes metastrongilídeos de pulmão de macacos. O autor complementa ainda a descrição original de Travassos e faz observações sobre a patogenia determinada pelos vermes no pulmão do macaco. É proposta uma nova combinação: a espécie é transferida do gênero Filaroides Van Beneden, 1858 para o gênero Filariopsis Van Thiel, 1926, em vista de apresentar três lábios na face oral; estes vermes passam a chamar-se Filariopsis barretoi (Travassos, 1921) Rego, 1974.

Recidiva de distrofias estromales corneales tras queratoplastia

Objectiu: valorar l'índex de recidiva simple o recidiva clínicament significativa dels diferents tipus de distròfies estromals anteriors en empelts corneals després cirurgia de queratoplàstia. Material i mètodes: S'ha realitzat una revisió retrospectiva del 1954 al 2008 al Centre d'Oftalmologia Barraquer, identificant a tots els pacients diagnosticats de distròfia corneal estromal anterior i de la membrana de Bowman (Distròfia de Reis Bücklers, Distròfia Granular, Distròfia reticular, distròfia macular) que han estat intervinguts de queratoplàstia penetrant (QP) o queratoplàstia laminar (QL). S'han utilitzat estadístics descriptius i la funció de supervivència amb les corbes de Kaplan Meier per dur a terme l'anàlisi de la mostra. Resultats: La mostra total del nostre estudi ha estat de 109 ulls de 66 pacients amb distròfies estromals anteriors operats de queratoplàstia: 8 casos de distròfies de la capa de Bowman (6 ulls amb CDRB o CDB-I (distròfia de Reis Bücklers), i 2 ulls amb CDTB o CDB-I (distròfia de Thiel Behnke)), 19 casos de distròfies granulars (CDG), 53 casos de distròfia de lattice (CDL) i 29 casos de distròfia macular (CDM). Amb un llarg de temps de seguiment (75-180 mesos de mitjana), la recurrència simple ha estat del 33% dels casos de CDRB amb 46 mesos de temps mitjà de supervivència, del 58, 8% dels casos de CDG amb 74.6 mesos de supervivència, el 41'5% de les CDL amb 106 mesos de supervivència i en el 10% dels casos amb CDM amb 96 mesos de temps mitjà de supervivència. La recurrència clínicament significativa es va manifestar en la seva majoria en els casos de CDL i CDG amb un temps mitjà de supervivència de 127.6 mesos i 124.1 mesos respectivament. El símptoma principal d'aquestes manifestacions clíniques va ser la disminució de la AV. Conclusió: La queratoplàstia penetrant és un tractament clàssic eficaç per als casos de distròfies estromals anteriors simptomàtics, amb opacitats profundes en l'estroma o fracàs previ d'altres teràpies menys invasives com la PTK. Com és d'esperar, per la seva origen genètic, l'aparició de recurrència de la distròfia després del trasplantament existeix i s'incrementa amb el major temps de seguiment. La tendència d'aquesta recidiva és a presentar inicialment en el pla cornial epitelial i requereix un llarg temps d'evolució per fer-se simptomàtica, especialment en els casos de CDG, CDL i CDM.

TGFBI (BIGH3) gene mutations in German families: two novel mutations associated with unique clinical and histopathological findings.

BACKGROUND: To report the clinical, histopathological and immunohistochemical findings of two novel mutations within the TGFBI gene. METHODS: The genotype of 41 affected members of 16 families and nine sporadic cases was investigated by direct sequencing of the TGFBI gene. Clinical, histological and immunohistochemical characteristics of corneal opacification were reported and compared with the coding region changes in the TGFBI gene. RESULTS: A novel mutation Leu509Pro was detected in one family with a geographic pattern-like clinical phenotype. Histopathologically we found amyloid together with non-amyloid deposits and immunohistochemical staining of Keratoepithelin (KE) KE2 and KE15 antibodies. In two families and one sporadic case the novel mutation Gly623Arg with a late-onset, map-like corneal dystrophy was identified. Here amyloid and immunohistochemical staining of only KE2 antibodies occurred. Further, five already known mutations are reported: Arg124Cys Arg555Trp Arg124His His626Arg, Ala546Asp in 13 families and five sporadic cases of German origin. The underlying gene defect within the TBFBI gene was not identified in any of the four probands with Thiel-Behnke corneal dystrophy. CONCLUSIONS: The two novel mutations within the TGFBI gene add another two phenotypes with atypical immunohistochemical and histopathological features to those so far reported.