Newborn hearing screening failure and maternal factors during pregnancy.

OBJECTIVE: Temporary conductive hearing loss due to amniotic fluid accumulation in the middle ear cavity may lead to failure (false positive) in newborn hearing screening tests. The aim of this study was to identify whether amniotic fluid index has association with failure of the initial newborn otoacoustic emission (OAE) screening test. METHODS: A cohort study in a tertiary hospital center (Royal Victoria Hospital, Montréal) was constructed from 70 newborns that failed the OAE test, but passed a subsequent auditory brainstem response (ABR) test, and 75 randomly selected newborns that passed initial otoacoustic emission testing. Maternal (including the amniotic fluid index in the third trimester) and newborn clinical data were extracted from medical records. Statistical association models were built to determine variables that influenced hearing screen passage or failure. RESULTS: The two arms of the cohort had no significant differences in maternal or child clinical indices, including in amniotic fluid index. Calculated as individual odds ratios, maternal tobacco [95% CI of odds ratio: 0.04, 0.59, p = 0.0078], and drug use [95% CI of odds ratio: 0.0065, 0.72, p = 0.058] [borderline significance] were associated with failing the otoacoustic emission testing. CONCLUSIONS: Amniotic fluid index was not found to be associated with failure of otoacoustic emission screening in newborns. However, our study unveiled an interesting unexpected association of OAE failure with maternal smoking and/or drug use. This finding can help alleviate some of the time, cost and parental anxiety related to failed OAE screening. In selected cases of maternal smoking or drug use we might want to replace or add OAE to the ABR test in newborn hearing screening protocols, that don't perform both tests before discharge.

Semaphorin 4C Protects against Allergic Inflammation: Requirement of Regulatory CD138+ Plasma Cells.

The regulatory properties of B cells have been studied in autoimmune diseases; however, their role in allergic diseases is poorly understood. We demonstrate that Semaphorin 4C (Sema4C), an axonal guidance molecule, plays a crucial role in B cell regulatory function. Mice deficient in Sema4C exhibited increased airway inflammation after allergen exposure, with massive eosinophilic lung infiltrates and increased Th2 cytokines. This phenotype was reproduced by mixed bone marrow chimeric mice with Sema4C deficient only in B cells, indicating that B lymphocytes were the key cells affected by the absence of Sema4C expression in allergic inflammation. We determined that Sema4C-deficient CD19+CD138+ cells exhibited decreased IL-10 and increased IL-4 expression in vivo and in vitro. Adoptive transfer of Sema4c-/- CD19+CD138+ cells induced marked pulmonary inflammation, eosinophilia, and increased bronchoalveolar lavage fluid IL-4 and IL-5, whereas adoptive transfer of wild-type CD19+CD138+IL-10+ cells dramatically decreased allergic airway inflammation in wild-type and Sema4c-/- mice. This study identifies a novel pathway by which Th2-mediated immune responses are regulated. It highlights the importance of plasma cells as regulatory cells in allergic inflammation and suggests that CD138+ B cells contribute to cytokine balance and are important for maintenance of immune homeostasis in allergic airways disease. Furthermore, we demonstrate that Sema4C is critical for optimal regulatory cytokine production in CD138+ B cells.

Mesenchymal stem cell transplantation to promote bone healing.

An overall decline in the availability of osteogenic precursor cells and growth factors in the bone marrow microenvironment have been associated with impaired bone formation and osteopenia in humans. The objective of the current study was to determine if transplantation of mesenchymal stromal cells (MSC) from a healthy, young donor mouse into an osteopenic recipient mouse could enhance osseointegration of a femoral implant. MSC harvested from normal young adult mice differentiated into bone forming osteoblasts when cultured on implant grade titanium surfaces ex vivo and promoted bone formation around titanium-coated rods implanted in the femoral canal of osteopenic recipient mice. Micro computed tomographic imaging and histological analyses showed more, better quality, bone in the femur that received the MSC transplant compared with the contra-lateral control femur that received carrier alone. These results provide pre-clinical evidence that MSC transplantation promotes peri-implant bone regeneration and suggest the approach could be used in a clinical setting to enhance bone regeneration and healing in patients with poor quality bone.