Biomedical subjects

K B McConnell

Publications and source records attributed to K B McConnell.

4 recordsLinked to original sources

PubMed1997

Pulmonary dysfunction in neonatal SP-B-deficient mice.

Pulmonary function was assessed in newborn wild-type and homozygous and heterozygous surfactant protein B (SP-B)-deficient mice after birth. SP-B +/+ and SP-B+/- mice became well oxygenated and survived postnatally. Although lung compliance was decreased slightly in the SP-B+/- mice, lung volumes and compliances were decreased markedly in homozygous SP-B-/- mice. They died rapidly after birth, failing to inflate their lungs or oxygenate. SP-B proprotein was absent in the SP-B-/- mice and was reduced in the SP-B+/- mice, as assessed by Western analysis. Surfactant protein A, surfactant proprotein C, surfactant protein D, and surfactant phospholipid content in lungs from SP-B+/- and SP-B-/- mice were not altered. Lung saturated phosphatidylcholine and precursor incorporation into saturated phosphatidylcholine were not influenced by SP-B genotype. Intratracheal administration of perfluorocarbon resulted in lung expansion, oxygenation, and prolonged survival of SP-B-/- mice and in reduced lung compliance in SP-B+/+ and SP-B+/- mice. Lack of SP-B caused respiratory failure at birth, and decreased SP-B protein was associated with reduced lung compliance. These findings demonstrate the critical role of SP-B in perinatal adaptation to air breathing.

Animals↗

PubMed1988

Impact of recurrent otitis media on middle ear function, hearing, and language.

Whether recurrent otitis media in infants and young children is followed by delayed language development was addressed by following 210 normal subjects longitudinally through the first 2 years of life with pneumatic otoscopy and tympanometry performed at every physician encounter. Otitis accounted for 26% of the medical visits. One hundred fifty-six of these children had speech and hearing evaluation at 2 years of age. Thirty percent of the children with recurrent otitis media had a mild or moderate hearing loss. However, after multiple speech and language tests, we could not identify a delay in language acquisition in the otitis-prone children. At 3 to 4 years old, 36 children, including nine with a hearing loss at 2 years of age, were retested; all nine had normal hearing. Recurrent otitis media induced a temporary decrease in hearing sensitivity demonstrable at 2 years of age, which appeared to resolve as the children matured and which was not associated with delay in language acquisition.

Child, Preschool↗

PubMed1985

A longitudinal study of the detection of otitis media in the first two years of life.

A number (210) of children were followed longitudinally through the first two years of life with pneumatic otoscopy and electroacoustic immitance, tympanometry, at every physician encounter. Tympanometry proved to have a high predictive value (86%) for detecting normal ears but relatively poor predictive value (58%) for detecting abnormal ears when utilized as a routine screening procedure with every clinic visit. In part the tympanometrically abnormal ears which appeared normal in otoscopic exam were temporally related to recent episodes of otitis and concurrent upper respiratory congestion, but many were unrelated to detectable middle ear pathology. These observations detract from the utility of tympanometry as a screening tool for middle ear pathology.

Acoustic Impedance Tests↗

PubMedDate not supplied

Clinical studies of pneumococcal vaccines in infants. II. Efficacy and effect on nasopharyngeal carriage.

Two polyvalent pneumococcal polysaccharide vaccines were evaluated in about 200 infants. Vaccination did not affect nasopharyngeal carriage of pneumococci nor was titer of type-specific antibody, as determined by radioimmunoassay, predictive of subsequent carriage of individual types. Otitis media occurred with equal frequency in vaccinated and in control children. One of four episodes of documented pneumococcal bacteremia occurred after vaccination and was caused by a type contained in the vaccine. No indication of either an efficacious or detrimental effect of pneumococcal polysaccharide vaccines administered to infants was seen in this study.

Antibodies, Bacterial↗