Permanent childhood hearing impairment in infants admitted to the neonatal intensive care unit: nested case-control study.

The prevalence of permanent childhood hearing impairment (PCHI) in infants admitted to a neonatal intensive care unit (NICU) is higher than that in the general population. Our study objective was to identify risk factors associated with PCHI in infants who required admission to the NICU for more than 48 h. We performed a case-control study, including infants of all gestational ages who were admitted to NICU for more than 48 h and who underwent newborn hearing screening between 2005 and 2019. Infants admitted to NICU and diagnosed with PCHI by formal audiology were classified as "cases". The "controls" were infants who were admitted to NICU and did not have PCHI. Cases and controls (1:4) were matched based on their birth gestation, birthing place, and treating NICU. The prevalence of PCHI in infants admitted to NICU was 6.3% as compared with our general population prevalence of 0.25%. There were 77 cases and 269 controls during the study period. The median age at diagnosis of PCHI in these infants was 132 days (interquartile range 75.5-518.5). Using regression analysis, "any ventilation episodes", presence of seizures, and major congenital anomalies were significantly associated with PCHI in infants of all gestational ages. There were higher prevalence of PCHI in preterms (<32 weeks) who received furosemide and lower prevalence with antenatal use of magnesium sulphate.Conclusions: In our study, the prevalence of hearing loss was high in infants admitted to NICU. Gestation-specific risk factors identified in this case-control study would help in counselling of parents. What is Known: • In the UK, 1-2/1000 infants are born with hearing loss and infants admitted to the neonatal unit for 48 h or more have increased prevalence of hearing loss (1 in 100 live births). • Identification of risk factors in infants admitted to neonatal unit would help with risk stratification and further management. What is New: • In our study, infants admitted to the neonatal unit had higher prevalence of hearing loss (6.3 in 100 live births). • In infants across all gestational age "any ventilation episodes", presence of seizures, and severe congenital anomalies were associated with a statistically significant increase in prevalence of hearing loss. Higher prevalence of hearing loss was noted in preterm infants (<32 weeks) who received furosemide treatment and lower prevalence was noted with antenatal use of magnesium sulphate.

Characterization of Protease-Activated Receptor (PAR) ligands: Parmodulins are reversible allosteric inhibitors of PAR1-driven calcium mobilization in endothelial cells.

Several classes of ligands for Protease-Activated Receptors (PARs) have shown impressive anti-inflammatory and cytoprotective activities, including PAR2 antagonists and the PAR1-targeting parmodulins. In order to support medicinal chemistry studies with hundreds of compounds and to perform detailed mode-of-action studies, it became important to develop a reliable PAR assay that is operational with endothelial cells, which mediate the cytoprotective effects of interest. We report a detailed protocol for an intracellular calcium mobilization assay with adherent endothelial cells in multiwell plates that was used to study a number of known and new PAR1 and PAR2 ligands, including an alkynylated version of the PAR1 antagonist RWJ-58259 that is suitable for the preparation of tagged or conjugate compounds. Using the cell line EA.hy926, it was necessary to perform media exchanges with automated liquid handling equipment in order to obtain optimal and reproducible antagonist concentration-response curves. The assay is also suitable for study of PAR2 ligands; a peptide antagonist reported by Fairlie was synthesized and found to inhibit PAR2 in a manner consistent with reports using epithelial cells. The assay was used to confirm that vorapaxar acts as an irreversible antagonist of PAR1 in endothelium, and parmodulin 2 (ML161) and the related parmodulin RR-90 were found to inhibit PAR1 reversibly, in a manner consistent with negative allosteric modulation.

Friction force microscopy of alkylphosphonic acid and carboxylic acids adsorbed on the native oxide of aluminum.

Monolayers of alkylphosphonic acids (APA) and alkylcarboxylic acids (ACA) on magnetron-sputtered aluminum films have been investigated by friction force microscopy (FFM), contact angle measurement, and polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Clear evidence has been provided from PM-IRRAS that friction coefficients, determined from FFM data, may be correlated directly with variations in adsorbate molecular structure. The friction coefficient increased with the length of the adsorbate molecule, but reached a limiting value when the alkyl chain of the adsorbate contained eight carbons in the case of APA or 12 carbons in the case of ACA. For a given alkyl chain length, APA monolayers yielded coefficients of friction that were similar to those of monolayers of alkylthiols of the same length, but smaller than those of ACA. These data indicate that APA monolayers are better ordered than ACA monolayers. These inferences were supported by PM-IRRAS data, which enabled the density of gauche defects to be estimated and correlated with variations in the coefficient of friction.