Biomedical subjects

E Neely Atkinson

Publications and source records attributed to E Neely Atkinson.

24 records · Page 2Linked to original sources

PubMed2002

Fluorescence spectroscopy for cervical precancer detection: Is there variance across the menstrual cycle?

This study assesses one possible cause of inter-patient variation in fluorescence spectroscopy of the cervix: the menstrual cycle. Ten patients with no history of an abnormal Pap smear were seen daily throughout 30 consecutive days of their cycle. Fluorescence excitation-emission matrices were measured from three cervical sites on each patient. Principal component analysis was used to determine which spectral regions varied with the day of the cycle. Classification was performed to assess the influence of menstrual cycle on precancer diagnosis. Variations in the principal component scores and the redox ratio values show that the fluorescence emission spectra at 340-380 nm excitation appear to correlate with the cell metabolism of the cervical epithelium throughout the menstrual cycle; these changes do not affect diagnostic classification. The menstrual cycle affects intra-patient variation but does not appear to cause a significant level of inter-patient variation. It does not need to be controlled for in optical detection strategies based on fluorescence spectroscopy.

Female↗

PubMedDate not supplied

Predictors of breast and cervical screening in Vietnamese women in Harris County, Houston, Texas.

The Vietnamese are a quickly growing, important part of the Texas population. Breast cancer is known to have different biologic characteristics in Vietnamese women. In order to develop appropriate intervention and screening strategies, we conducted a study of barriers to cervical and breast screening in Vietnamese women in Harris County, Tex. Our objective was to characterize the demographic factors, beliefs, and barriers to cervical and breast cancer screening in our study population and test the effect of these on Papanicolaou test, breast self-examination (BSE), medical breast examination (MBE), and mammography use. The Health Belief Model Scales for Measuring Beliefs Related to Breast Cancer (Champion VL, Nursing Research 1993;42:139-143) was the framework used to assess attitudes regarding risk of breast cancer and to design a component assessing risk of cervical cancer. The questionnaire addressed susceptibility, seriousness, benefits, barriers, and health about screening for breast and cervical cancer. It was translated into Vietnamese and back-translated into English prior to use. The questionnaire was mailed to Harris County residents. Those returned were entered into a database. The data were analyzed for validity using Chronbach's alpha. Simple descriptive analyses and nominal logistic regression identified predictors of Papanicolaou test, BSE, MBE, and mammography use. Twelve hundred surveys were mailed out to Vietnamese women using the telephone directory and the church directories in Harris County; 209 were returned and entered into the database. Of the respondents, 67% had ever received a Papanicolaou test; of these, 89% had received a Papanicolaou test within the past year; 55% of respondents had performed a BSE, 45% of patients received an MBE, and 45% of respondents had ever received a mammogram (15% of respondents had a mammogram during the previous year). The most significant predictors of Papanicolaou test, BSE, MBE, and mammography use were marital status (being married), high educational level, lack of barriers, a family history of the cancer, older age, and increased perception of seriousness. Compared to other studies of Vietnamese women, the women in Texas are among the highest users of the Papanicolaou test, BSE, MBE, and mammography. Barriers and incentives to breast and cervical screening were similar to those in other studies.

Adult↗

PubMedDate not supplied

Effect of probe pressure on cervical fluorescence spectroscopy measurements.

Fluorescence spectroscopy is a promising technology for detection of epithelial precancers and cancers. While age and menopausal status influence measurements in the cervix, other variables do not significantly affect the diagnosis. In this study we examine probe pressure as a variable. A fiber optic probe to measure fluorescence spectra at different calibrated levels of pressure was designed and tested. A pilot study was conducted measuring fluorescence excitation emission matrices in 20 patients at light, medium, and firm pressure. Spectroscopic data were pre-processed and analyzed to compare mean peak intensities as a function of pressure. Further statistical analyses tested for differences in intensities at each excitation/emission wavelength pair. Four providers made measurements from 41 sites; 33 yielded good quality spectroscopic data (22 squamous normal, 7 squamous abnormal, 3 columnar normal, 1 transformation zone) from 17 of 20 patients. At all pressure levels, abnormal tissue showed less fluorescence intensity than normal tissue, and post-menopausal patients showed higher fluorescence intensity than premenopausal patients, consistent with previous analyses. A permutation analysis suggests that pressure does not significantly affect fluorescence intensity or lineshape. While other studies are needed to confirm these findings, this study suggests that fluorescence spectroscopy is a robust technology likely not influenced by fiber optic probe pressure.

Adult↗

PubMedDate not supplied

Calibration standards for multicenter clinical trials of fluorescence spectroscopy for in vivo diagnosis.

In the context of clinical trials, calibration protocols for optical instruments that ensure measurement accuracy and the ability to carry out meaningful comparisons of data acquired from multiple instruments are required. A series of calibration standards and procedures are presented to assess technical feasibility of optical devices for cervical precancer detection. Measurements of positive and negative standards, and tissue are made with two generations of research grade spectrometers. Calibration accuracy, ability of standards to correct and account for changes in experimental conditions, and device components are analyzed. The relative frequency of measured calibration standards is investigated retrospectively using statistical analysis of trends in instrument performance. Fluorescence measurements of standards and tissue made with completely different spectrometers show good agreement in intensity and lineshape. Frequency of wavelength calibration standards is increased to every 2 h to compensate for thermal drifts in grating mount. Variations in illumination energy detected between standards and patient measurements require probe redesign to allow for simultaneous acquisition of illumination power with every patient measurement. The use of frequent and well-characterized standards enables meaningful comparison of data from multiple devices and unambiguous interpretation of experiments among the biomedical optics community.

Calibration↗

PubMedDate not supplied

Natural history of cervical intraepithelial neoplasia: a meta-analysis.

OBJECTIVE: To determine the probabilities of transition of stages in the cervical cancer by conducting a meta-studies on the topic. STUDY DESIGN: We identified health states of interest in the natural history of cervical precancer, identified all possible papers that could meet selection criteria, developed relevance and acceptability criteria for inclusion, then thoroughly reviewed the selected studies. To determine the transition probability data we used a random effects model. We determined probabilities for 4 health state transitions. The 6-month mean predictive transition probability (95% confidence intervals with "prediction interval" in parentheses) for high grade squamous intraepithelial lesions (HSIL) to cancer was 0.0037 (0.00004, 0.03386), for low grade squamous intraepithelial lesions (LSIL) to HSIL was 0.0362 (0.00055, 0.23220), for HSIL to LSIL was 0.0282 (0.00027, 0.35782), and for LSIL to normal was 0.0740 (0.00119, 0.42672). CONCLUSION: The transition probabilities between cervical cancer health states for 6-month intervals are small; however, the cumulative risk of cervical cancer is significant. Markers to identify the cervical precursors that will lead to the transition to cervical cancer are needed.

Confidence Intervals↗

PubMedDate not supplied

PTEN expression in tamoxifen-associated endometrial cancers.

UNLABELLED: Tamoxifen is associated with increased rates of endometrial hyperplasia and adenocarcinoma. Our previous work suggested tamoxifen-associated endometrial cancers might be associated with p53 mutations. PTEN, a tumor suppressor gene, is altered in low-grade endometrial carcinoma. This study evaluates PTEN immunohistochemical (IHC) expression in tamoxifen-associated endometrial cancers. MATERIALS AND METHODS: Twenty-eight endometrial carcinoma specimens were examined from patients with a history of breast cancer. Patients who had taken Tamoxifen (15) were compared to non-users (13). IHC staining was performed for PTEN; overexpression was defined as greater than 70% positivity. RESULTS: The mean duration of tamoxifen use was 3.3 years (3-171 months). Four out of 15 (27%) tamoxifen users expressed PTEN compared with 2 out of 13 (15%) of non-users. CONCLUSION: In this study, it appears that tamoxifen-associated endometrial cancers are not significantly different from sporadic endometrial cancer with regards to PTEN IHC expression, although there is a trend towards retained PTEN expression.

Aged↗