Qualitative analysis of parents' experience with early detection of hearing loss.

AIMS: To determine key themes from parents' comments on paths to diagnosis and intervention for their children with hearing loss, following introduction of at-risk neonatal hearing screening and modification of distraction test screening for infants not at-risk. METHODS: Parents of children born in 1993 in Victoria, Australia, who were eligible for screening via the Victorian Infant Hearing Screening Program and who were subsequently diagnosed with a permanent congenital hearing loss and fitted with hearing aids prior to the year 2000 were asked to complete a semi-structured questionnaire shortly after aid fitting. Two researchers independently analysed parent comments using the constant comparative method. RESULTS: Parents of 82 children (61%) replied to the questionnaire. Themes analysis revealed a generally positive response to neonatal ABR screening, with a mixed response to the distraction test; powerful emotions experienced by parents at diagnosis including denial and shock; frustration arising from delays in diagnosis, and communication difficulties with providers. Special difficulties testing children with other medical and developmental problems, confusion about tympanostomy tube insertion, and difficulty with wearing hearing aids were also reported. Some children had experienced problems in the school setting. Experience of post-diagnostic services was generally positive. CONCLUSIONS: Parents need greater support both during the testing of screen failures and at the time of diagnosis. Providers need more training in how to communicate findings to parents, particularly at times when parents are experiencing strong emotions. Parents need more strategies to enable hearing aid wearing in very young children. Some children with additional medical, developmental, and behavioural problems need specialised approaches to testing.

Clerkship curricular revision based on the Ambulatory Pediatric Association and the Council on Medical Student Education in Pediatrics guidelines: does it make a difference?

OBJECTIVE: To compare general pediatric knowledge acquisition and clinical problem-solving skills by students pre- and postcurricular reform based on the 1994 Ambulatory Pediatric Association and the Council on Medical Student Education in Pediatrics (APA-COMSEP) curricular guidelines. SETTING: A large, urban academic medical center. SUBJECTS: Third-year medical students on a required clerkship in Pediatrics. INTERVENTION: Pre- and postcurricular revision, the students were given both the National Board of Medical Examiners (NBME) Pediatric Subject Examination and an objective examination, which was developed in-house, based on the APA-COMSEP guidelines (Pediatric Clerkship Examination [PCE]). Baseline data before curricular revision were obtained on 52 students from May 1995 to May 1996. After curricular redesign in May 1996, data were obtained on 42 students from May 1996 to May 1997. Curricular revision focused on the following: defining educational principles, selecting teaching strategies, defining learning objectives, implementing the curriculum, and evaluating the students with an examination. RESULTS: Before curricular revision, the average NBME score was 521 +/- 122. The average PCE score was 53.7% +/- 10.1%. After curricular revision, the average NBME score was 520 +/- 109, and the average PCE score was 67.7% +/- 8.4%. Content areas showing the greatest improvement were fluids and electrolytes, issues pertaining to the newborn, and health supervision. CONCLUSIONS: Our baseline data indicate that despite spending two thirds of the clerkship in the ambulatory setting, students did not acquire adequate general pediatric knowledge or clinical problem-solving ability. After broad clerkship revision based on the APA-COMSEP Core Curriculum, students' acquisition of general pediatric knowledge and clinical problem-solving improved significantly, as measured by the PCE. The overall NBME Pediatric Subject Examination scores did not reflect this increased acquisition of general pediatric knowledge.

Structural and functional organization of herpes simplex virus DNA polymerase investigated by limited proteolysis.

The 1235 residue herpes simplex virus DNA polymerase is a prototype alpha-like DNA polymerase and also an antiviral drug target. To investigate its organization, we mapped favored cleavage sites for seven proteases and identified three major classes of stable proteolytic fragments: 70-85-kDa N-terminal fragments, 50-70-kDa fragments that start near residues 600-700, and 12-kDa C-terminal fragments. In coimmunoprecipitation experiments, the first two classes of fragments remained associated; thus, cleavage in the center of the protein did not resolve structurally separate domains. In contrast, the 12-kDa C-terminal fragments did not remain associated with other fragments, suggesting a small separable C-terminal domain. The 70-85-kDa N-terminal fragments contained 3'-5' exonuclease and ribonuclease H activities; however, cleavage at the center of the molecule or near the C terminus appeared to destroy DNA polymerase activity. All three major classes of fragments bound DNA in DNA-cellulose chromatography and Southwestern blot analyses. The C-terminal fragments bound the viral polymerase processivity factor, UL42. The results map activities to regions of herpes simplex virus polymerase and suggest a model for its organization that may be pertinent to other DNA polymerases.

Conformational changes induced in herpes simplex virus DNA polymerase upon DNA binding.

Herpesvirus DNA polymerases are prototypes for alpha-like DNA polymerases and important targets for antiherpesvirus drugs. We have investigated changes in the catalytic subunit of herpes simplex virus DNA polymerase following DNA binding by using the techniques of endogeneous fluorescence quenching and limited proteolysis. The fluorescence studies revealed a reduction in the rate of quenching by acrylamide in the presence of DNA without changes in the wavelength of the emission peak or in the lifetime of the fluorophore, consistent with the possibility of conformational changes. Strikingly, the proteolysis studies revealed that binding to a variety of natural and synthetic DNA and RNA molecules induced the appearance of a new cleavage site for trypsin near residue 1060 of the protein and increased cleavage by trypsin near the center of the protein. The extent of these cleavages correlated with the affinity of the polymerase for these ligands. These data provide strong evidence that binding to nucleic acid polymers induces substantial localized conformational changes in the polymerase. The locations of enhanced tryptic cleavage near sites implicated in substrate recognition and interaction with a processivity factor suggest that the conformational changes are important for catalysis and processivity of this prototype alpha-like DNA polymerase. Inhibition of these changes may provide a mechanism for antiherpesvirus drugs.