Biomedical subjects

L Rodney Long

Publications and source records attributed to L Rodney Long.

4 recordsLinked to original sources

PubMed2006

Age-related changes of the cervix influence human papillomavirus type distribution.

Approximately 15 human papillomavirus (HPV) types cause virtually all cervical cancer whereas other HPV types are unrelated to cancer. We were interested in whether some noncarcinogenic types differ from carcinogenic in their affinity for the cervical transformation zone, where nearly all HPV-induced cancers occur. To examine this possibility, we tested cervical specimens from 8,374 women without cervical precancer and cancer participating in a population-based study in Guanacaste for >40 HPV types using PCR. We compared age-group specific prevalences of HPV types of the alpha9 species, which are mainly carcinogenic and include HPV16, to the genetically distinct types of the alpha3/alpha15 species (e.g., HPV71), which are noncarcinogenic and common in vaginal specimens from hysterectomized women. We related HPV detection of each group to the location of the junction between the squamous epithelium of the ectocervix and vagina and the columnar epithelium of the endocervical canal. Models evaluated the independent effects of amount of exposed columnar epithelium (ectopy) and age on the presence of alpha9 or alpha3/alpha15 types. Prevalence of alpha9 types (7.6%) peaked in the youngest women, declined in middle-aged women, and then increased slightly in older women. By contrast, prevalence of alpha3/alpha15 types (7.6%) tended to remain invariant or to increase with increasing age. Detection of alpha9 infections increased (P(trend) < 0.0005) but alpha3/alpha15 infections decreased (P(trend) < 0.0005) with increasing exposure of the columnar epithelia. Older age and decreasing cervical ectopy were independently positively associated with having an alpha3/alpha15 infection compared with having an alpha9 infection. These patterns need to be confirmed in other studies and populations. We suggest that these genetically distinct groups of HPV types may differ in tissue preferences, which may contribute to their differences in carcinogenic potential.

Adult↗

PubMed2006

Digital tools for collecting data from cervigrams for research and training in colposcopy.

Colposcopy is a critical part of gynecologic practice but has documented deficiencies, including lack of correlation between the colposcopic appearance and the severity of underlying neoplasia, limited reproducibility, and difficulty in the optimal placement of colposcopically directed biopsies. In a collaborative effort to improve colposcopy, we are analyzing digitized cervigram images from National Cancer Institute-funded studies. Specifically, the National Cancer Institute has collected close to 100,000 cervigrams, digitized to create a database of images of the uterine cervix for research, training, and education. In addition to the cervigram images, this database contains clinical, cytologic, and molecular information at multiple examinations of 15,000 women, with password and ID labeling strategies to protect patient privacy. The National Library of Medicine has designed two web-accessible software tools. The Boundary Marking Tool allows experts on colposcopy to perform an evaluation of the pictures and to mark boundary regions of normal and abnormal regions of the uterine cervix; these evaluations are collected and saved in the database. The Multimedia Database Tool enables retrieval of test and image biomedical data according to specific queries, for example, all women with cervical intraepithelial neoplasia 3 whose cytologic results are atypical squamous cells of undetermined significance. The resource soon will be available as an open resource, via a teaching tool coordinated by a database manager, which will permit a variety of applications for teaching and research. In this article, we describe the perceived need for the resource and its components.

Biomedical Research↗

PubMed2004

Image informatics at a national research center.

Image informatics at the Communications Engineering Branch of the Lister Hill National Center for Biomedical Communications (LHNCBC), an R&D division of the National Library of Medicine (NLM), includes document and biomedical images. In both domains, research into computer-assisted methods for information extraction, and the implementation of prototype systems incorporating such methods, is central to our mission. Current document image research focuses on extracting bibliographic data from scanned journal articles. Current biomedical imaging work focuses on content-based image retrieval (CBIR) and related problems in segmentation, indexing, and classifying collections of images of the spine and of the uterine cervix.

Diagnostic Imaging↗

PubMed2004

Content-based image retrieval for large biomedical image archives.

Content-Based Image Retrieval (CBIR) has been a topic of research interest for nearly a decade. Approaches to date use image features for describing content. A survey of the literature shows that progress has been limited to prototype systems that make gross assumptions and approximations. Additionally, research attention has been largely focused on stock image collections. Advances in medical imaging have led to growth in large image collections. At the Lister Hill National Center for Biomedical Communication, an R&D division of the National Library of Medicine, we are conducting research on CBIR for biomedical images. We maintain an archive of over 17,000 digitized x-rays of the cervical and lumbar spine from the second National Health and Nutrition Examination Survey (NHANES II). In addition, we are developing an archive of a large number of digitized 35 mm color slides of the uterine cervix. Our research focuses on developing techniques for hybrid text/image query-retrieval from the survey text and image data. In this paper we present the challenges in developing CBIR of biomedical images and results from our research efforts.

Archives↗