Mouse mutants for the nicotinic acetylcholine receptor ß2 subunit display changes in cell adhesion and neurodegeneration response genes.

Mice lacking expression of the ß2 subunit of the neuronal nicotinic acetylcholine receptor (CHRNB2) display abnormal retinal waves and a dispersed projection of retinal ganglion cell (RGC) axons to their dorsal lateral geniculate nuclei (dLGNs). Transcriptomes of LGN tissue from two independently generated Chrnb2-/- mutants and from wildtype mice were obtained at postnatal day 4 (P4), during the normal period of segregation of eye-specific afferents to the LGN. Microarray analysis reveals reduced expression of genes located on the cell membrane or in extracellular space, and of genes active in cell adhesion and calcium signaling.

Prophylactic effect of clarithromycin in skin flap complications in cochlear implants surgery.

Objectives/hypothesis: To assess the usefulness of postoperative clarithromycin versus classical postoperative prophylaxis with occlusive dressing to prevent cochlear implant skin flap complications.

Study Design: Cohort study.

Methods: Surgical site infections were compared in four groups: 1) ceramic/classical postoperative cares (21 patients), 2) titanium-silicon/classical postoperative cares (75), 3) ceramic/clarithromycin (24), and 4) titanium-silicon/clarithromycin (76).

[Surgical options for hearing loss in patients with osteogenesis imperfecta].

The aim of the study is to present the severe, extensive lesions in the temporal bone appearing in the mildest forms of osteogenesis imperfecta, correlate these with audiometric results and discuss the possible surgical treatments available. We present three patients suffering hearing loss due to osteogenesis imperfecta type 1 to various functional degrees. All patients underwent an audiological, medical and radiological evaluation and were then treated with different surgical procedures.

Complications and pitfalls of cochlear implantation in otosclerosis: a 6-year follow-up cohort study.

Objective: To describe and discuss the midterm complications and pitfalls reported in patients with otosclerosis who received a cochlear implant.

Study Design: Prospective cohort study.

Setting: Tertiary referral center.

Retinal waves in mice lacking the beta2 subunit of the nicotinic acetylcholine receptor.

The structural and functional properties of the visual system are disrupted in mutant animals lacking the beta2 subunit of the nicotinic acetylcholine receptor. In particular, eye-specific retinogeniculate projections do not develop normally in these mutants. It is widely thought that the developing retinas of beta2(-/-) mutants do not manifest correlated activity, leading to the notion that retinal waves play an instructional role in the formation of eye-specific retinogeniculate projections.

Formation of eye-specific retinogeniculate projections occurs prior to the innervation of the dorsal lateral geniculate nucleus by cholinergic fibers.

We compared the developmental periods in the mouse when projections from the two eyes become segregated in the dorsal lateral geniculate nucleus with the time when this nucleus becomes innervated by cholinergic fibers from the brainstem. Changes in labeling patterns of different tracers injected into each eye revealed that segregation of retinogeniculate inputs commences at postnatal day five (P5) and is largely complete by P8. Immunocytochemical staining showed that cholinergic neurons are present in the parabrachial region of the brain stem on the day of birth.