Biomedical subjects

Martial Guillaud

Publications and source records attributed to Martial Guillaud.

15 recordsLinked to original sources

PubMed2006

DNA ploidy compared with human papilloma virus testing (Hybrid Capture II) and conventional cervical cytology as a primary screening test for cervical high-grade lesions and cancer in 1555 patients with biopsy confirmation.

BACKGROUND: Because 80% of cervical cancers arise in low-resource settings, many inexpensive strategies are being tested. In that spirit, the authors are testing large-scale genomic or DNA ploidy measurements as an inexpensive and semiautomated strategy. METHODS: Patients entered either a screening or diagnostic study of several optical technologies: quantitative cytology, quantitative histopathology, and fluorescence and reflectance spectroscopy using a point probe, a multispectral digital colposcope, or a combination of the two. We calculated sensitivities, specificities, positive and negative predictive values, and their confidence interval testing conventional cytology, Hybrid Capture (HC) II testing, and DNA ploidy measured on the Feulgen-stained quantitative Pap smear. RESULTS: The current investigation reports on 1555 patients for whom colposcopically directed biopsies were read 3 times by study pathologists. The final histopathologic diagnosis was high grade (cervical intraepithelial neoplasia [CIN] 2, CIN 3, carcinoma in situ [CIS], and cancer) in 16% of patients. Using high-grade squamous intraepithelial lesions (SILs) histopathology as the threshold and gold standard, the sensitivity and specificity, respectively, were: 0.47 and 0.96 for conventional cytology, 0.91 and 0.80 for HC II, and 0.59 and 0.93 for DNA ploidy. The positive and negative predictive values (PPV, NPV) for conventional cytology were 0.70 and 0.90, 0.46 and 0.98 for HC II, and 0.63 and 0.92 for DNA ploidy. CONCLUSIONS: DNA ploidy shows comparable sensitivity, specificity, PPV, and NPV values to conventional cytology and HC II. Unlike conventional cytology, DNA ploidy is semiautomated and can be performed in less than 8 hours. Cost effectiveness studies are under way, but in the authors' laboratory DNA ploidy is inexpensive.

Adolescent↗

PubMed2005

Subvisual chromatin changes in cervical epithelium measured by texture image analysis and correlated with HPV.

OBJECTIVES: In this study, we are testing the hypothesis that human papillomavirus (HPV) positivity is correlated with chromatin texture in the cell. Interim analyses are important since this study involves 2000 patients and generates 6000 biopsy specimens that will be subjected to quantitative histopathological analysis and correlated to HPV positivity as measured by the Hybrid Capture II test (Digene; Gaithersberg, MD) and both HPV-DNA and mRNA by the polymerase chain reaction (PCR). The studies of optical technologies, from which we derive this sample, use the colposcopically directed and histopathologically classified cervical biopsy as the gold standard. In this report, we describe the results of an interim analysis of quantitative histopathology and chromatin texture as correlates of HPV infection using the cyto-savant system in cytologically and histopathologically negative specimens. METHODS: A group of 1544 patients entered the optical technology trials, generating 3275 biopsies and 1544 Papanicolaou readings. Two hundred forty-eight patients were cytologically and histopathologically negative. Study pathologists reviewed histologic samples 3 times in a blinded fashion. Non-overlapping, quantitatively stained nuclei were selected from the samples by the pathologists. HPV testing was done using the PCR method and the Hybrid Capture II test. Statistical analysis involved the creation of a classification matrix using a linear discriminant analysis. The matrix was trained on HPV-positive cells by PCR. The analysis included the random creation of both a training set and a validation set that were classified based on the discrimination score obtained by correlating nuclear texture with HPV positivity. RESULTS: The sensitivity of the classification was 52-54% and the specificity was 77-78%. Overall, a 68% predicted accuracy was achieved for both the training set and the test set. The agreement of a test and training set shows that the sets created randomly are indeed similar, and that the discrimination score worked equally well in both sets of cells. Once a cell-by-cell algorithm for HPV positivity was derived, HPV positivity was recalculated on the basis of cell-by-cell texture features. HPV positivity was then recalculated on both a per-biopsy basis and a per-patient basis. For HPV 16 and 18, the positivity rate was 70% on a per-biopsy basis and 73% on a per-patient basis. CONCLUSIONS: Although these results are preliminary, they suggest that texture features reflecting chromatin condensation may correlate with HPV positivity. The current sample is histologic, the analysis suggests that in a cytologic sample, HPV positivity could be detected or confirmed by texture features computed as part of an HPV-associated score. Additional biologic markers could be used as needed. While this study was performed on histologic samples, a study of cytologic samples would be more useful. Future studies will examine chromatin texture compared to HPV integration and mRNA HPV expression.

Adolescent↗

PubMed2005

Classification using the cumulative log-odds in the quantitative pathologic diagnosis of adenocarcinoma of the cervix.

INTRODUCTION: This study develops a method that discriminates between normal and cancerous tissue sections (i.e., populations of cells) using a statistical model applied to high-dimensional quantitative measurements made on a sample of cells. MATERIALS AND METHODS: We use a cumulative log-odds model to create a score for a tissue section using the information from the cells within that tissue section. Then, a threshold is determined using receiver operating characteristic (ROC) curve analysis. The method was tested using data from cervical adenocarcinomas, adenocarcinoma in situ, and normal columnar tissue. RESULTS: Using 120 potential features, we analyzed the data for staining-independent features. Twenty-two features were statistically significant. We then calculated the log-odds and created a score, followed by ROC curve analysis. The operating point which maximizes the sum of the specificity and sensitivity achieved a sensitivity of 100% with a specificity of 85%. CONCLUSION: The cumulative log-odds performs well in classifying tissue sections using high-dimensional data measured at the cellular level, like that of quantitative pathology. This methodology potentially has applications in pathology, radiology, and optical technologies.

Adenocarcinoma↗

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↗

PubMed2005

Correlation of human papillomavirus type 16 and human papillomavirus type 18 e7 messenger RNA levels with degree of cervical dysplasia.

Infection with certain types of human papillomavirus (HPV) is a necessary event in the development of cervical carcinoma; however, not all women who become infected with HPV will progress to cancer. Much is known about the molecular influence of HPV E6 and E7 proteins on the malignant transformation. Little is known about the additional factors needed to drive the process. Quantitative real-time PCR was used to quantitate mRNA expression of the E7 gene in women exhibiting normal epithelium, low-grade squamous intraepithelial lesions (LSIL), and high-grade squamous intraepithelial lesions (HSIL). Prevalence of mRNA transcripts was lower among normal women (27%) than for women with LSIL (40%) and HSIL (37%). Mean levels ranged from 2.0 (ln scale per 20 ng cDNA) among normal women to 4.2 among those with HSIL, with a significant trend (P=0.008). This trend was only significant for HPV 18 transcripts if separately analyzed by HPV type. The transcriptional activity of HPV 18 is higher than that of HPV 16 and increases with increasing level of dysplasia. This is in concert with the findings of other studies, and reinforces the notion that HPV 18 is a more aggressive viral type. Real-time PCR of viral transcripts could provide a more efficient method to analyze the oncogenic potential within cells from a cervical swab, thus providing a way to better screen women who may progress to higher grade lesions or invasive carcinoma from those who will spontaneously regress.

Adult↗

PubMed2005

Optical technologies for cervical neoplasia: update of an NCI program project grant.

Cervical cancer is the second most common cancer in women worldwide and the leading cause of cancer mortality in women in developing countries. In the United States, over $6 billion is spent annually in the evaluation and treatment of low-grade lesions, many of which do not develop into full-blown cancer. In developing countries, however, the chief concern is that cervical cancer goes undetected because of the cost of testing and the lack of resources and trained personnel to screen and diagnose the disease. The goal of the National Cancer Institute Program Project Grant CA82710 is to assess the emerging technologies of fluorescence and reflectance spectroscopy and quantitative cytology and histopathology for the diagnosis of cervical neoplasia. All of these technologies should decrease mortality, morbidity, and the cost of treating cervical cancer.

Computational Biology↗

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↗