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Biomedical subjects

F W Denny

Publications and source records attributed to F W Denny.

At least 37 records · Page 2Linked to original sources

Epidemiology of colonization by nontypable Haemophilus influenzae in children: a longitudinal study.

Eighty-six nasopharyngeal isolates of Haemophilus influenzae were prospectively obtained from three children who attended a day care center from infancy until early childhood (five to seven years). A majority of the strains were nontypable. We analyzed strains by comparing their biotypes and by performing electrophoresis of outer membrane proteins on polyacrylamide gels. Profiles of outer membrane proteins were very heterogeneous and could not be used as the basis for the development of a subtyping scheme. The children characteristically carried a nasopharyngeal strain defined by a unique outer membrane pattern for a period of months, lost it, and then acquired a new strain. We probed the outer membrane proteins of a child's strains by the western blot technique with serum obtained serially from the child. Isolates whose outer membrane proteins appeared identical on stained gels generally had similar antigenic bands on western blots but were occasionally immunologically distinct. Serum immunoglobulins of the IgG class that reacted with the outer membrane proteins did not appear to change greatly over time or to play a role in preventing or terminating colonization. We conclude that nasopharyngeal colonization in children by nontypable H. influenzae is a dynamic process and that factors that cause loss and acquisition of strains remain to be determined.

Antigens, Bacterial↗

Pulmonary function in children with sarcoidosis.

To document pulmonary function abnormalities in children with sarcoidosis, we reviewed the records of all children with this disease at the North Carolina Memorial Hospital. Spirometry was performed by 34 of 60 children at initial presentation and was repeated by 16 at least 1 yr after presentation (mean, 3.9 yr). Those with and without pulmonary function data available were similar in age, sex, race, and clinical manifestations at presentation. Results indicate that at presentation, 50% of children had the characteristic functional changes of restrictive lung disease (mean % predicted FVC, 79.8 +/- 16.0). Fifteen percent had a FVC of 70 to 80% predicted, 32% had a FVC of 50 to 70% predicted, and 3% had a FVC less than 50% predicted. The TLC and FRC supported the diagnosis of restrictive lung disease. There were 15% who had obstructive changes. Children with auscultatory abnormalities and parenchymal changes on chest radiograph had more severe decrements in pulmonary function; however, specific symptoms did not predict decrements in pulmonary function. There was significant improvement in lung function at the last pulmonary function test performed (mean % predicted FVC, 97.1 +/- 18.8).

Adolescent↗

Serum cotinine as a measure of tobacco smoke exposure in children.

To document passive smoke exposure, we measured concentrations of serum cotinine, a major metabolite of nicotine, in 38 young children and compared the results with the smoking histories of home residents. Cotinine was detected in 26 children (68%), of which ten had no household exposure according to a questionnaire. The serum cotinine concentration was significantly elevated in blacks compared with whites after controlling for the number of smokers in the home. After stratifying by race, there was a significant direct correlation between the serum cotinine concentration and the number of smokers in the home, the amount smoked by the mother, and the amount smoked by others in the home. We conclude that the serum cotinine concentration is a useful indicator of the actual exposure of young children to tobacco smoke and that unexplained racial differences in cotinine levels exist.

Black or African American↗

Croup: an 11-year study in a pediatric practice.

The etiology and epidemiology of croup were studied in a pediatric group practice over an 11-year period, 1964 to 1975. Croup was diagnosed in 951 instances in 6,165 cases of lower respiratory tract infection (LRI) studied. As census figures of the practice clientele were available, attack rates were calculated. The incidence of total LRI was highest in the first year of life. In contrast, the attack rate for croup was highest in the second year of life; the rate declined gradually after that age. Croup was not diagnosed in the first month of life. Boys were 1.43 times more likely to develop croup than were girls. Three hundred sixty agents were isolated from the 951 croup cases. The parainfluenza viruses accounted for 74.2% of all isolates; 65% of the parainfluenza isolates were classified as parainfluenza virus type 1. Respiratory syncytial virus, influenza viruses A and B, and Mycoplasma pneumoniae were the only other agents isolated in appreciable numbers. The propensity of various agents to produce croup symptoms in children with LRI due to specific microorganisms was 58% for parainfluenzae type 1,60% for parainfluenzae type 2, and 29% for parainfluenzae type 3; similar figures for the other agents varied from 5% to 16%. The role of the various agents in the etiology of croup varied with patient age and depended on the propensity of the agent to produce the croup syndrome and the frequency of isolation of the agent at that age. The parainfluenza viruses were the most important croup agents at all ages; respiratory syncytial virus caused croup in children less than 5 years of age whereas the influenza viruses and M pneumoniae were significant causes of croup only in children more than 5 to 6 years old. Croup occurred predominately in late fall and early winter, times when the parainfluenza viruses, especially type 1, occurred most frequently. The epidemiology of croup differs from that of bronchiolitis, pneumonia, and tracheobronchitis; knowledge of this should be helpful to the clinician caring for children with LRI.

Age Factors↗

A longitudinal study of respiratory viruses and bacteria in the etiology of acute otitis media with effusion.

We analyzed data from a 14-year longitudinal study of respiratory infections in young children to determine the relative importance of viral respiratory infection and nasopharyngeal colonization with Streptococcus pneumoniae and Haemophilus influenzae as factors influencing the occurrence of acute otitis media with effusion. The incidence of this disorder was increased in children with viral respiratory infections (average relative risk, 3.2; P less than 0.0001). Infection with respiratory syncytial virus, influenza virus (type A or B), and adenovirus conferred a greater risk of otitis media than did infection with parainfluenza virus, enterovirus, or rhinovirus. Colonization of the nasopharynx with Str. pneumoniae or H. influenzae had a lesser effect on the incidence of the disease (average relative risk; 1.5; P less than 0.01). Infections with the viruses more closely associated with acute otitis media (respiratory syncytial virus, adenovirus, and influenza A or B) were correlated with an increased risk of recurrent disease. Prevention of selected otitis-associated viral infections should reduce the incidence of this disease.

Acute Disease↗