Biomedical subjects

Martial Guillaud

Publications and source records attributed to Martial Guillaud.

10 recordsLinked to original sources

PubMed2005

Nuclear morphometry as a biomarker for bronchial intraepithelial neoplasia: correlation with genetic damage and cancer development.

BACKGROUND: Bronchial carcinomas are preceded by epithelial morphologic changes. The variation in interpretation of these grades of intraepithelial neoplasia makes it difficult to determine its natural history and utility of histopathology as a surrogate endpoint biomarker. The objective of this study was to quantitate morphologic changes of intraepitherlial neoplasia and validate its utility through correlation with histopathology, allelic loss, and cancer development. METHODS: Quantitative nuclear morphometry was performed on 47 normal bronchial biopsies and 28 invasive cancer to generate a morphometry index (MI) that was applied to 1,096 bronchial biopsies from 230 volunteers who were current smokers (> or =25 pack-years) and 30 patients who had cancer. In a subset of 631 biopsies, MI was correlated with frequency of loss of heterozygosity at nine chromosomal regions (14 polymorphic markers). RESULTS: A significant correlation was found between MI and allelic loss in six of nine chromosomal regions. As part of patient long-term follow-up, 12 sites that progressed to cancer were identified and had significantly increased MIs relative to nonprogressing sites. Significant overlap in the MIs was found between most grades of intraepithelial neoplasia. CONCLUSIONS: In chemoprevention trials, nuclear morphometry can supplement histopathology as a Surrogate Endpont Biomarker (SEB) because it is quantitative, collelates well with genetic damage, and may predict cancer development.

Biopsy↗

PubMed2004

Exploratory analysis of quantitative histopathology of cervical intraepithelial neoplasia: objectivity, reproducibility, malignancy-associated changes, and human papillomavirus.

BACKGROUND: As part of a project to evaluate emerging optical technologies for cervical neoplasia, our group is performing quantitative histopathological analyses of biopsy specimens from 1,190 patients. Objectives in the interim analysis are (a) quantitatively assessing progression of the neoplastic process of cervical intraepithelial neoplasia (CIN)/squamous intraepithelial lesions (SIL), (b) detecting malignancy-associated changes (MACs), and (c) phenotypically measuring human papillomavirus (HPV) detected by DNA testing. METHODS: The diagnostic region of interest (ROI) from immediately adjacent sections were imaged, and the basal lamina and surface of the superficial layer were delimited. Nonoverlapping quantitatively stained nuclei were selected from 1,190 samples with histopathological characteristics of normal (929), koilocytosis (130), CIN 1 (40), CIN 2 (23), and CIN 3/carcinoma in situ (CIS) (68). A fully automatic procedure located and recorded the center of every nucleus in the region of interest (ROI). We used linear discriminant analysis to assess the changes between normal and CIN 3/CIS. RESULTS: Scores computed from the cell-by cell features and the clinical grade of CIN/SIL were highly correlated, as were those of the architectural features and the clinical grade of CIN/SIL. We found even higher correlations between a combination of cell-by-cell and architectural scores, and clinical grade. Using these scores, we found MACs in the normal biopsy specimens from patients with high-grade CIN/SIL. Furthermore, the same scores correlated with the molecular detection of HPV. CONCLUSIONS: Quantitative histopathology can be used in large clinical trials as an objective and reproducible measure of CIN/SIL. Detectable phenotypic changes correlate well with CIN/SIL neoplastic progression. It can also be used to infer the presence of CIN/SIL (MACs) and molecular changes associated with increased risk of cancer development (high-risk HPV).

DNA, Viral↗

PubMed2004

Quantitative histopathology and chromosome 9 polysomy in a clinical trial of 4-HPR.

OBJECTIVE: This trial examined the use of 4-hydroxyphenyl-retinamide (4-HPR), demonstrated to be a potent inhibitor of carcinogenesis in vitro and in animal models, in patients with cervical intraepithelial neoplasia (CIN) grades 2 to 3. Quantitative pathology and chromosome 9 polysomy were used to understand the biology and quantify the clinical histopathologic changes observed. METHODS: Patients were randomized to 4-HPR or placebo for 6 months and followed for six more months. Cervical biopsies were obtained at baseline, 6 months, and 12 months; the biopsies were read blinded three times by the study pathologist. Feulgen-stained sections were also obtained and analyzed using computer-assisted image cytometry. Chromosome 9 polysomy was performed on tissue slices using in situ hybridization and measured quantitatively. Statistical analyses were carried out in S-Plus (Insightful Corporation, Seattle, WA) and R. RESULTS: The interim analysis, planned for 40 patients, was carried out on 39. The 6- and 12-month analyses showed a statistically significant difference between the two study arms. When code was broken, the 4-HPR-treatment arm was found to have fared less well than placebo. Analyses of Feulgen-stained sections provided a quantitative measure of the increase of DNA content and texture features. Chromosome 9 polysomy was also measured using image analysis. The changes observed were consistent with those of cells displaying cancerous changes, indicating a lack of response. CONCLUSION: 4-HPR is not active at 200 mg/day. The interim analysis was helpful in directing the study; and, in this case, ending it. The intermediate endpoint biomarkers of quantitative histomorphometry and chromosome 9 polysomy yielded quantitative and repeatable results consistent with the findings of the clinical pathologist.

Anticarcinogenic Agents↗

PubMed2004

Quantitative histopathological analysis of cervical intra-epithelial neoplasia sections: methodological issues.

OBJECTIVES: As part a Program Project to evaluate emerging optical technologies for cervical neoplasia, our group is performing quantitative histopathological analysis of biopsies from 1,800 patients. Several methodological issues have arisen with respect to this analysis: (1) Finding the most efficient way to compensate for staining intensity variation with out losing diagnostic information; (2) Assessing the inter- and intra-observer variability of the semi-interactive data collection; and (3) the use of non-overlapping cells from the intermediate layer only. METHODS: Non-overlapping quantitatively stained nuclei were selected from 280 samples with histopathological characteristics of normal (199), koilocytosis (37), CIN 1 (18), CIN 2 (10) and CIN 3 (16). Linear discriminant analysis was used to assess the diagnostic information in three different feature sets to evaluate and compare staining intensity normalization methods. Selected feature values and summary scores were used to evaluate intra- and inter-observer variability. RESULTS: The features normalized by the internal subset of the imaged cells had the same discriminatory power as those normalized by the control cells and by both normalization methods seem to have additional discriminatory power over the set of features which do not require normalization. The use of the internal subset decreased the image acquisition time by approximately 50% at each center, respectively. The intra- and inter-observer variability was of a similar size. Good performance was obtained by measuring the intermediate layer only. CONCLUSION: The use of intensity normalization from a subset of the imaged non-overlapping intermediate layer cells works as well as or better than any of the other methods tested and provides a significant timesaving. Our intra- and inter-observer variability do not seem to affect the diagnostic power of the data. Although this must be tested in a larger data set, the use of intermediate layer cells only may be acceptable when using quantitative histopathology.

Cell Nucleus↗

PubMed2004

Quality assurance system using statistical process control: an implementation for image cytometry.

AIMS: Optical technologies have shown some promise for improving the care of cervical neoplasia. We are currently evaluating fluorescence and reflectance spectroscopy and quantitative cyto-histopathology for cervical neoplasia screening and diagnosis. Here we describe the establishment and application of a quality assurance (QA) system for detecting system malfunctions and assessing the comparability of four image cytometers used in a multicenter clinical trial. METHODS: Our QA system involves three levels of evaluation based on the periodicity and complexity of the measurements. We implemented our QA system at three image cytometers at the British Columbia Cancer Agency and one at M.D. Anderson Cancer Center. The measurements or tasks were performed daily, monthly, and semi-annually. The current and voltage of the lamp, the calibration image characteristics, and the room temperature were checked daily. Long-term stability over time, short-term variability over time, and spatial response field uniformity were evaluated monthly. Camera linearity was measured semi-annually. Control charts based on statistical process control techniques were used to detect when the system did not perform optimally. RESULTS: Daily measurements have shown good consistency in room temperature, lamp and calibration behaviour. Monthly measurements have shown small coefficients of variation between and within the four devices. There have been greater differences between sessions than within sessions. Comparability among the four systems is reasonably good. Semi-annual measurements have shown stable camera linearity. QA events were detected using the QA system. Multiple examples of event detection leading to correction of system malfunction are described in this report. CONCLUSIONS: QA programs are critical for ensuring data integrity and therefore for the conduct of multicenter clinical trials.

Female↗

PubMed2003

Light scattering from cervical cells throughout neoplastic progression: influence of nuclear morphology, DNA content, and chromatin texture.

A number of noninvasive fiber optic optical technologies are under development for real-time diagnosis of neoplasia. We investigate how the light scattering properties of cervical cells are affected by changes in nuclear morphology, DNA content, and chromatin texture, which occur during neoplastic progression. We used a Cyto-Savant computer-assisted image analysis system to acquire quantitative nuclear features measurements from 122 Feulgen-thionin-stained histopathologic sections of cervical tissue. A subset of the measured nuclear features was incorporated into a finite-difference time-domain (FDTD) model of cellular light scattering. The magnitude and angular distribution of scattered light was calculated for cervical cells as a function of pathologic grade. The nuclear atypia strongly affected light scattering properties. The increased size and elevated DNA content of nuclei in high-grade lesions caused the most significant changes in scattering intensity. The spatial dimensions of chromatin texture features and the amplitude of refractive index fluctuations within the nucleus impacted both the angular distribution of scattering angles and the total amount of scattered light. Cellular scattering is sensitive to changes in nuclear morphology that accompany neoplastic progression. Understanding the quantitative relationships between nuclear features and scattering properties will aid in the development of noninvasive optical technologies for detection of precancerous conditions.

Cell Nucleus↗

PubMed2003

Light scattering from normal and dysplastic cervical cells at different epithelial depths: finite-difference time-domain modeling with a perfectly matched layer boundary condition.

The finite-difference time-domain (FDTD) method provides a flexible approach to studying the scattering that arises from arbitrarily inhomogeneous structures. We implemented a three-dimensional FDTD program code to model light scattering from biological cells. The perfectly matched layer (PML) boundary condition has been used to terminate the FDTD computational grid. We investigated differences in angle-dependent scattering properties of normal and dysplastic cervical cells. Specifically, the scattering patterns and phase functions have been computed for normal and dysplastic cervical cells at three different epithelial depths, namely, basal/parabasal, intermediate, and superficial. Construction of cervical cells within the FDTD computational grid is based on morphological and chromatin texture features obtained from quantitative histopathology. The results show that angle-dependent scattering characteristics are different not only for normal and dysplastic cells but also for cells at different epithelial depths. The calculated scattering cross-sections are significantly greater for dysplastic cells. The scattering cross-sections of cells at different depths indicate that scattering decreases in going from the superficial layer to the intermediate layer, but then increases in the basal/parabasal layer. This trend for epithelial cell scattering has also been observed in confocal images of ex vivo cervical tissue.

Algorithms↗

PubMed2003

Use of nuclear morphometry characteristics to distinguish between normal and abnormal cervical glandular histologies.

This is a methodological study exploring the use of quantitative histopathology applied to the cervix to discriminate between normal and cancerous (consisting of adenocarcinoma and adenocarcinoma in situ) tissue samples. The goal is classifying tissue samples, which are populations of cells, from measurements on the cells. Our method uses one particular feature, the IODs-Index, to create a tissue level feature. The specific goal of this study is to find a threshold for the IODs-Index that is used to create the tissue level feature. The main statistical tool is Receiver Operating Characteristic (ROC) curve analysis. When applied to the data, our method achieved promising results with good estimated sensitivity and specificity for our data set. The optimal threshold for the IODs-Index was found to be 2.12.

Adenocarcinoma↗

PubMed2003

Surrogate end-point biomarker analysis in a retinol chemoprevention trial in current and former smokers with bronchial dysplasia.

Epidemiological studies suggested that vitamin A may be protective against lung cancer, however, recent chemoprevention trials with beta-carotene, a precursor of vitamin A, demonstrated enhancement of lung carcinogenesis among smokers. Whether vitamin A is beneficial or harmful in chemoprevention of lung cancer in smokers has not been resolved. This study was designed to determine the effect of retinol alone in current and former smokers using bronchial dysplasia, nuclear morphometry and retinoic acid receptor-beta (RAR-beta) mRNA expression as surrogate end-point biomarkers (SEBs). Eighty-one current or former smokers with a smoking history of >/=30 pack-years were randomized to receive either placebo or retinol (50,000 IU per day) for six months. Fluorescence bronchoscopy was performed prior to treatment to localize areas suggestive of dysplasia. At least 4 bronchial biopsies were taken per subject including at least two biopsies from apparently normal areas. The same areas were precisely re-biopsied after 6 months. Any new areas suggestive of dysplasia were also biopsied. Changes in the SEBs were assessed before and after treatment. At baseline, the frequency of biopsies negative for RAR-beta expression was: normal (23%), hyperplasia (28%), metaplasia (41%), mild dysplasia (41%), and moderate/severe dysplasia (44%). There was no significant difference in the regression rate between the retinol and placebo groups using histopathology and nuclear morphometry as SEBs. The likelihood of regression was found to be lower in those who continued to smoke during the study (OR=1.86 for those smoking >10 cigarettes per day, p=0.084 to OR=0.95, p=0.26 for those smoking 20+ per day compared to ex-smokers). Retinol was not effective in the up-regulation of RAR-beta in lesions with bronchial dysplasia. We postulate that the lack of effect of retinol on RAR-beta expression among individuals who continued to smoke while taking retinol may be due to suppressive effect of tobacco smoke constituents on RAR-beta expression and/or altered cellular metabolism of retinol to retinoic acid and its isomers.

Aged↗

PubMed2002

A randomized phase IIb trial of anethole dithiolethione in smokers with bronchial dysplasia.

BACKGROUND: Results from preclinical studies have suggested that the organosulfur compound anethole dithiolethione (ADT) may be an effective chemopreventive agent for lung cancer. We conducted a phase IIb study to determine the effects of ADT in smokers with bronchial dysplasia. METHODS: One hundred twelve current and former smokers with a smoking history of at least 30 pack-years and at least one site of bronchial dysplasia identified by an autofluorescence bronchoscopy-directed biopsy were randomly assigned to receive placebo or ADT at 25 mg orally thrice daily for 6 months. Each subject then underwent a follow-up bronchoscopy-directed biopsy. We used changes in histopathologic grade and nuclear morphometry index (MI) as the primary and secondary end point biomarkers, respectively. Chi-square tests with continuity correction were used to compare response rates on a lesion- and person-specific basis between the two study groups. All statistical tests were two-sided. RESULTS: One hundred one subjects had a follow-up bronchoscopy. In the lesion-specific analysis, progression rate of pre-existing dysplastic lesions by two or more grades and/or the appearance of new lesions was statistically significantly lower in the ADT group (8%) than in the placebo group (17%) (P<.001; difference = 9%, 95% confidence interval [CI] = 4% to 15%). In the person-specific analysis, the disease progression rate was statistically significantly lower in the ADT group (32%) than in the placebo group (59%) (P =.013; difference = 27%, 95% CI = 6% to 48%). The two treatment groups did not differ statistically significantly in terms of nuclear MI. Among individuals with an abnormal nuclear MI before treatment (29 in the ADT group and 25 in the placebo group), the progression rate in the ADT group (41%) was substantially lower than that in the placebo group (60%), although the difference was not statistically significant (P =.28; difference = 19%, 95% CI = -11% to 49%). Adverse events were mostly minor gastrointestinal symptoms that resolved with dose reduction or discontinuation of the medication. CONCLUSION: Our results suggest that, in smokers, ADT is a potentially efficacious chemoprevention agent for lung cancer.

Adult↗