Biomedical subjects

A D Collins

Publications and source records attributed to A D Collins.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Vaginal Chlamydia trachomatis infection in children with sexual contact.

To determine whether vaginal infections with Chlamydia trachomatis in children were associated with sexual contact, 50 children ages 1 to 12 years with a history of sexual contact and 34 children without such a history were studied. Vaginal, throat and rectal cultures for C. trachomatis and Neisseria gonorrhoeae were performed in all children. Three children with sexual contact and none of the children without a history of sexual contact had vaginal infections. The three infected children were asymptomatic and only one had had vaginal intercourse. None of the 10 children with a history of sexual contact and gonorrheal vaginitis had C. trachomatis isolated. Although C. trachomatis vaginal infections as detected by vaginal cultures are infrequent, we recommend that all girls being evaluated for sexual contact be routinely cultured for C. trachomatis so that those infected can be treated.

Child↗

PubMedDate not supplied

An instrument to monitor the luminance of pattern visual evoked potential stimuli.

When recording pattern visual evoked potentials it is important that the overall luminance of the pattern and the relative luminance of the pattern elements (for example checks or bars) are maintained at a constant level. This paper describes a low-cost battery-powered instrument designed and constructed to measure the luminance of specific areas of the screen on which the pattern is projected.

Calibration↗

PubMedDate not supplied

Reduction in binocular enhancement of the visual-evoked potential during development accompanies increasing stereoacuity.

PURPOSE: To study the maturation of normal binocular vision. METHODS: Binocular visual function has been studied and monocular and binocular pattern reversal visual-evoked potentials (VEP) recorded in 20 normal subjects aged 5 to 43 years. RESULTS: Stereoacuity improved significantly between the age of 5 and adulthood. Mean stereoacuity for eight children measured by the Titmus test was 61 seconds of arc and 56 seconds of arc by the TNO test. For the 12 adults in the study, corresponding mean stereoacuities were 45 and 31 seconds of arc. Over the same timespan, binocular enhancement of the VEP P100 amplitude decreased. For the children aged 5 to 10 years, the mean binocular VEP enhancement to 20' checks was 1.60, whereas for young adults it was 1.19. There was no comparable change in the binocular enhancement to 40' checks, with mean binocular enhancement of 1.31 in the children and 1.26 in the young adults. Over the same age range, VEP latency also decreased. CONCLUSION: During visual maturation, improvement in stereoacuity is accompanied by a fall in binocular enhancement of the P100 amplitude of the VEP to small checks and a reduction in the P100 latency.

Adolescent↗