[Processing of interaural time differences in normal-hearing subjects and cochlear implant users with FSP and HDCIS coding strategy]

BACKGROUND

Sound localization is necessary for social interaction and remains challenging for bilateral cochlear implant (CI) users. This study investigated the influence of fine structure processing (FSP) coding strategies on temporal accuracy and source localization. The ability to discriminate between different interaural time differences (ITD) was measured objectively and compared.

MATERIALS AND METHODS

Fifteen normal-hearing subjects and five CI users participated in this study. Electrophysiological recording of mismatch negativity (MMN) and psychoacoustic tests with headphones and loudspeakers were conducted to measure and compare the discrimination of ITDs.

RESULTS

In normal-hearing subjects the discrimination threshold for ITD was 83-117 µs. Localization ability in a free sound field was below the limit of resolution. A significant MMN was measured. CI users showed a mean angle detection error of more than 30° and a discrimination threshold between 1100 and 2100 µs. Due to artifacts, no clear MMN component could be recorded.

CONCLUSION

This study shows that MMN can be used as an objective measure of ITD discrimination in normal-hearing participants. An indication that improvements in directional hearing can be achieved with the transfer of fine structure could not be provided by this study.

A feasibility study of trauma-sensitive obstetric care for low-income, ethno-racial minority pregnant abuse survivors

PURPOSE

This study evaluated the feasibility and acceptability of an integrated (psychological and obstetric) intervention for pregnant abuse survivors with posttraumatic stress symptoms (PTS) from low-income, ethno-racial minority backgrounds.

METHODS

Trauma-sensitive obstetrics to promote control, anxiety-reduction and empowerment (TO-CARE) offers cognitive-behavioral therapy (CBT) coping skills delivered over six sessions by therapists, coupled with trauma-sensitive obstetric care from specially-trained obstetric physicians.

RESULTS

Participants were 21 women who completed at least three sessions of CBT, totaling 51.2% of eligible participants. Participants received approximately one-third (M = 2.29; SD = 2.15) of their prenatal visits with obstetric residents trained in trauma-sensitive care. Nearly all participants (95%) reported that they benefited from the intervention. Although most participants demonstrated improvement in PTS, only four demonstrated reliable improvement, and two demonstrated reliable improvement in depression symptoms. These improvements appeared to be maintained at postpartum follow-up for two of the participants.

CONCLUSIONS

Our findings suggest that TO-CARE was acceptable to pregnant abuse survivors and may be a promising intervention to reduce symptoms of distress. Implications of the low retention rate for the CBT (51.2%) are discussed in the context of interventions for low-income minority pregnant women. Limitations regarding feasibility of the integrated intervention are discussed.

The trans-membrane domain of Bcl-2α, but not its hydrophobic cleft, is a critical determinant for efficient IP3 receptor inhibition

The anti-apoptotic Bcl-2 protein is emerging as an efficient inhibitor of IP3R function, contributing to its oncogenic properties. Yet, the underlying molecular mechanisms remain not fully understood. Using mutations or pharmacological inhibition to antagonize Bcl-2's hydrophobic cleft, we excluded this functional domain as responsible for Bcl-2-mediated IP3Rs inhibition. In contrast, the deletion of the C-terminus, containing the trans-membrane domain, which is only present in Bcl-2α, but not in Bcl-2β, led to impaired inhibition of IP3R-mediated Ca2+ release and staurosporine-induced apoptosis. Strikingly, the trans-membrane domain was sufficient for IP3R binding and inhibition. We therefore propose a novel model, in which the Bcl-2's C-terminus serves as a functional anchor, which beyond mere ER-membrane targeting, underlies efficient IP3R inhibition by (i) positioning the BH4 domain in the close proximity of its binding site on IP3R, thus facilitating their interaction; (ii) inhibiting IP3R-channel openings through a direct interaction with the C-terminal region of the channel downstream of the channel-pore. Finally, since the hydrophobic cleft of Bcl-2 was not involved in IP3R suppression, our findings indicate that ABT-199 does not interfere with IP3R regulation by Bcl-2 and its mechanism of action as a cell-death therapeutic in cancer cells likely does not involve Ca2+ signaling.

Signaltransduktionswege der Mechanotransduktion in Knochenzellen

Die Erhaltung der Knochenmasse wird durch die Interaktion von verschiedenen Faktoren, einschließlich systemischen Hormonen, lokalen Wachstumsfaktoren und mechanischer Belastung reguliert. Verantwortlich für die adaptive Antwort von Knochenzellen auf mechanische Belastung sind zelluläre Prozesse der Aufnahme, der Umwandlung des physikalischen Stimulus in strukturelle und biochemische Reaktionen, die als Mechanotransduktion bezeichnet werden. Osteoblasten und vor allem Osteozyten sind die mechanosensorischen Zellen des Knochens. Sie benötigen den mechanischen Stimulus für ihre Vitalität und Funktion. Die in der Mechanotransduktion aktivierten Signalwege wirken anabol auf die Knochenmasse. Hierzu gehören der WNT (wingless integration)/β-Catenin und der Östrogenrezeptor (ER)-Signalweg, die beide eine entscheidende Rolle in der Regulation von Knochenbildung und Knochenresorption spielen. Eine Aufklärung der Interaktion der Signalwege in der Mechanotransduktion durch geeignete In-vitro-und In-vivo-Experimente ist sinnvoll, um in Zukunft effektiv mechanische Signale in der Prävention und Intervention von/bei osteodegenerativen Krankheiten, wie z. B. Osteoporose, nutzen zu können.