Biomedical subjects

B Palcic

Publications and source records attributed to B Palcic.

At least 37 records · Page 2Linked to original sources

PubMed1995

Evidence of cumulative gene losses with progression of premalignant epithelial lesions to carcinoma of the bronchus.

Human bronchial carcinoma is thought to develop through progressive stages from basal cell hyperplasia to squamous metaplasia, dysplasia, carcinoma in situ, and finally invasive cancer. In this study, we used tissue microdissection to examine loss of heterozygosity of chromosomes 3p21, 5q21, and 9p21 at each stage of the epithelial progression to invasive cancers. Forty-eight premalignant/malignant bronchial sites were biopsied from 13 patients (including 9 subjects without cancer) using fluorescence bronchoscopy. Eighteen sites with moderate/severe dysplasia in 6 patients were subjected to bronchoscopic and molecular follow-up during a 3-month to 2-year period. Seven separate cases of advanced non-small cell bronchial cancers were also analyzed. From the baseline biopsies, the prevalence of 3p and 9p deletions increased significantly from no deletion in the hyperplasia/metaplasia samples (n = 9) to 37 and 31% of the informative cases, respectively, in the dysplasia samples (n = 29), to 100 and 83%, respectively, for the carcinomas in situ (n = 6), and 100% in the invasive cancers (n = 11). Chromosome 5q deletion was significantly more frequent in invasive cancers (70% of the informative cases) as compared to carcinoma in situ (40%), dysplasias (33%), and hyperplasia/metaplasia samples (11%). The number of chromosome alterations also increased significantly from the lowest to the highest grade lesions, showing evidence of accumulation of genetic damage from one group to another. The molecular follow-up analysis showed that the same genomic alteration can persist in a given dysplastic bronchial area for several months or years, and that the persistence or the regression of the molecular abnormality is well correlated with the evolution of the disease on follow-up. Our results suggest that molecular analysis of bronchial biopsies obtained by fluorescence bronchoscopy may be a very useful means to study the natural history of preinvasive bronchial lesions and the outcome of interventions, such as with chemopreventive treatment.

Aged↗

PubMed1995

3T3 cell motility and morphology before, during, and after exposure to extremely-low-frequency magnetic fields.

Automated image cytometry techniques were used to measure motility and morphology in 3T3 fibroblasts exposed to extremely-low-frequency (ELF) magnetic fields. Cell motility and morphology were measured as a function of time before, during, and after 3-4 hour exposures to vertically oriented, 100 microTRMS sinusoidal magnetic fields at various frequencies in the 10-63 Hz range. Sham exposures were also carried out. No static DC fields were applied, but the geomagnetic field was almost vertical and, therefore, had a large component (28.3 microT) parallel to the applied AC field. The morphology and motile behavior of the cells were characterized by mathematically defined descriptors, which were calculated and averaged for the exposure period as well as for control periods that preceded and followed the exposure period. Each experiment involved the tracking of 100 cells that were subjected to one of the test frequencies (unless a sham exposure was being conducted). Statistical analysis of the results showed that even small changes of 10-20% could be significant at the P < .05 level. Changes on this order were measured in a significant proportion of the experiments. However, because such results were seen for both the sham-exposed and the ELF-exposed cells, and because the range of values that was obtained for the sham exposures was the same as that obtained for the ELF exposures, we concluded that there was no evidence to show that any of the measured changes were attributable to the applied ELF magnetic field.

3T3 Cells↗

PubMed1995

Image cytometry and chemoprevention in cervical cancer.

Of the approximately 60 million Pap smears performed in the United States in 1995, about 8% or 5 million will show cytology that is "not negative" (ASCUS, AGCUS, LSIL, HSIL, etc.). Possibly 15% or about 0.7 million of these cases will have positive follow-up by repeated Pap smears, colposcopy or biopsy. More than 4 million will be false-positive smears based on the reference standard of biopsy or repeated smears. If no treatment or medical intervention was offered to the 0.7 million cytologically and histologically positive cases, perhaps 20,000 (3%) would develop into invasive cancer. Of the original 5 million cytologically "not negative" cases, fewer than 0.5% have the potential to develop into invasive cancer. While considerable attention has been paid to false-negatives in Pap screening, the above considerations indicate that the cytological and histological criteria for assessing the malignant potential of "not negative" samples might benefit from some refinement. Until such refinement occurs, any chemoprevention studies in cervix face a formidable signal-to-noise problem--worse than 1:30. This paper presents data from quantitative image cytometry of cervical smears for assessing the malignant potential of various "not negative" cases. We have approached this in two ways--by analyzing dysplastic cell nuclei and by analyzing the nuclei of cytologically normal cells growing in the vicinity of the neoplastic lesion. In both cases, nuclear features describing the distribution of the DNA in the cell nuclei (especially texture features) are the discriminating factors. Future research into the objective assessment of malignant potential of "not negative" cases is outlined.

Chemoprevention↗

PubMed1995

Detection of squamous neoplasia by fluorescence imaging comparing porfimer sodium fluorescence to tissue autofluorescence in the hamster cheek-pouch model.

BACKGROUND: Early neoplastic changes in the oral cavity may be difficult to detect. Fluorescence imaging using porphyrin-derived drugs has been used to enhance detection of neoplasia. Autofluorescence has also been used for this purpose. This paper compares autofluorescence to porfimer sodium-induced fluorescence in the detection of neoplasia in the hamster cheek-pouch model. MATERIALS AND METHODS: Neoplasia was induced in the hamster cheek pouch by the application of 9,10-dimethyl-1,2-benzanthracene. Animals were imaged either with injection of drug (porfimer sodium) or without drug (autofluorescence). Imaging was carried out using a laser-induced fluorescence detection system. Biopsies were performed on imaged sections and histologic grades were assigned. RESULTS: Porfimer sodium fluorescence provided 100% sensitivity and specificity in detection of neoplasia. The sensitivity and specificity with autofluorescence was 76% and 83%, respectively. CONCLUSIONS: Autofluorescence provides an accurate means of detecting early neoplastic changes in the hamster cheek-pouch model; however, porfimer sodium imaging does improve detection rates.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1995

Diagnostic imaging of the larynx: autofluorescence of laryngeal tumours using the helium-cadmium laser.

The use of tissue autofluorescence for the detection and localization of cancer of the larynx is described. In this pilot study, eight patients with probable carcinoma of the vocal folds underwent laryngoscopy in which the tissue autofluorescence spectra of normal and pathologically confirmed tumour tissue were acquired in vivo. Fluorescence images of the suspect areas were also acquired using the LIFE system (Xillix Technologies Corp.). The results suggest that the autofluorescence properties of laryngeal tissue, under 442 nm illumination, are similar to those of bronchial tissue and that the LIFE system has the potential to increase the accuracy of staging of cancer of the larynx and also to allow earlier diagnosis of tumours and their recurrence.

Carcinoma, Squamous Cell↗

PubMed1995

Cytometric analysis of ventricular myocyte nuclei in idiopathic dilated cardiomyopathy: a tool for evaluation of disease progression?

The progression of idiopathic dilated cardiomyopathy (IDC) is governed by factors that remain obscure. The disease pathway toward cell degeneration or death results in irreversible myocyte change including nuclear cytometric alterations which may be evaluable and ultimately correlated with other measures of disease evolution. Using a novel image cytometry system, we analysed differences in ventricular myocyte nuclear morphology and DNA content and distribution in right and left ventricular free wall myocardium and in ventricular septal myocardium from 11 normal and 13 IDC human autopsy hearts. Nine morphological features of IDC myocyte nuclei differed significantly (P < 0.001) from normal. These were used to establish a classification matrix and cytometry-based assessment and allowed correct categorization of left and right ventricular and ventricular septal myocyte nuclei in concordance with their respective pathological diagnosis (i.e. normal or IDC) 71%, 81% and 77% of the time. Additionally, four photometric features were significantly different (P < 0.005) in IDC versus normal hearts, as were three discrete texture features (P < 0.001). Thus, the spectrum of myocyte nuclei seen in IDC have highly characteristic and measurable morphologic, photometric and texture features. Our findings indicate the potential value of cytometry in the classification of myocytes with regards to a disease continuum and suggest its applicability in both clinical and experimental studies.

Adult↗

PubMed1995

Spectroscopic and microscopic characteristics of human skin autofluorescence emission.

To improve the understanding of human skin autofluorescence emission, the spectroscopic and microscopic characteristics of skin autofluorescence were studied using a combined fluorescence and reflectance spectroanalyzer and a fiber optic microspectrophotometer. The autofluorescence spectra of in vivo human skin were measured over a wide excitation wavelength range (350-470 nm). The excitation-emission matrices of in vivo skin were obtained. An excitation-emission maximum pair (380 nm, 470 nm) was identified. It was revealed that the most probable energy of skin autofluorescence emission photons increases monotonically and near linearly with increasing excitation photon energy. It was demonstrated that the diffuse reflectance, R, can be used as a first order approximation of the fluorescence distortion factor f to correct the measured in vivo autofluorescence spectra for the effect of tissue reabsorption and scattering. The microscopic in vitro autofluorescence properties of excised skin tissue sections were examined using 442 nm He-Cd laser light excitation as an example. It was demonstrated that the fluorophore distribution inside the skin tissue is not uniform and the shapes of the autofluorescence spectra of different anatomical skin layers vary. The result of this study confirms that the major skin fluorophores are located in the dermis and provides an excellent foundation for Monte Carlo modeling of in vivo autofluorescence measurements.

Fluorescent Dyes↗

PubMed1995

Comparison of DNA measurement performed by flow and image cytometry of embedded breast tissue sections.

Tissue sections are important for morphometric studies, such as the analysis of architectural pattern of tissues as well as nuclear morphology and chromatin texture describing DNA distribution in nuclei. Tissue sections are generally not recommended for use in DNA ploidy measurements due to possible errors based on sectioned and overlapped nuclei. However, image cytometry (IC) on tissue sections has the advantage of preserved architecture and selective sampling of nuclei. This is particularly important for the analysis of specimens with small areas of diseases tissue or with a variety of histologic patterns in the same region, such as premalignant changes or in situ tumors. To evaluate the potential of measurements on breast tissue sections in the estimation of DNA ploidy status, we compared IC and flow cytometry (FC) measurements on formalin-fixed breast cancer tissue from 51 paraffin-embedded blocks. For each specimen the DNA index and ploidy were determined by both methods. DNA indices of IC and FC corresponded roughly in 66% of cases. Agreement in ploidy was achieved in about 80% (40/51) of cases, where some of the discrepancies could be explained by the differences between invasive cancer and ductal carcinoma in situ (DCIS) illustrated by IC. Both methods agreed highly in aneuploid cases. However, about 50% of FC diploid cases were aneuploid by IC. Despite significant shortcomings of measurements obtained on archival tissues, meaningful data can be obtained not only by FC but also by IC performed on tissue sections.(ABSTRACT TRUNCATED AT 250 WORDS)

Aneuploidy↗

PubMed1995

Differences in quantitative nuclear features between ductal carcinoma in situ (DCIS) with and without accompanying invasive carcinoma in the surrounding breast.

The aim of this study was to demonstrate differences in nuclear morphology between ductal carcinoma in situ (DCIS) without an invasive component and DCIS associated with invasive carcinoma in adjacent breast tissue. DCIS specimens of 60 non-comedo and 21 comedo cases were obtained from two groups of patients with or without invasive carcinoma of the breast. The analysis of DCIS nuclei was performed on formalin fixed deparaffinized thin sections stained with a stoichiometric stain following the Feulgen procedure. Nuclear features, related to nuclear size, shape and DNA distribution, were quantitatively characterized by high resolution image cytometry. Features associated with the presence of invasive carcinoma in the surrounding breast tissue were identified in DCIS nuclei (independent of nuclear grade). Features selected by the stepwise procedure of the discriminant function analysis were typically texture features describing the DNA distribution in the nucleus. A classification function based on the selected nuclear features predicted accurately the presence of invasive carcinoma in all comedo DCIS and in 80% of non-comedo DCIS cases. Our results indicate that quantitative nuclear features of DCIS nuclei are predictive of the accompanying invasion and may be helpful as a new tool in evaluation of DCIS patients.

Breast Neoplasms↗

PubMed1995

Malignancy-associated changes in bronchial epithelial cells in biopsy specimens.

A total of 152 normal bronchial biopsy sections--63 from normal subjects, 42 from patients with dysplasia, 28 from patients with early or advanced lung cancer with squamous and nonsquamous histopathology, and 19 from resected lung cancer patients--were examined for the presence of malignancy-associated changes (MACs). A standard, white light bronchoscope examination and a multispectral fluorescence bronchoscope examination were performed on every subject to determine the status of the bronchial epithelial tissue. Any suspect areas were biopsied to determine the status of the area and to establish the highest grade of abnormality in the patient. In addition, for every subject, a bronchoscopically normal area of the bronchus in the opposite lung or another lobe was biopsied. The specimens were confirmed to be normal by conventional histopathologic criteria using hematoxylin and eosin stain. Sections of biopsies were stained using a DNA stoichiometric stain, and approximately 250 images of visually normal epithelial cell nuclei from each of the biopsies were collected, as were approximately 40 images of leukocyte cell nuclei. For each of these images > 60 nuclear features were calculated that quantified the size, shape and DNA volume of the nuclei as well as DNA spatial organization in the nuclei. The features were then used to train an automated classifier to recognize normal epithelial cell nuclei from normal subjects and normal-appearing epithelial cell nuclei (MAC cell nuclei) from lung cancer patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗

PubMed1995

Malignancy-associated changes in the breast. Changes in chromatin distribution in epithelial cells in normal-appearing tissue adjacent to carcinoma.

Malignancy-associated changes (MACs) have been described as subtle morphologic changes in normal-appearing tissues adjacent to or distant from malignant tumors. MACs might be applicable as a marker of occult malignancy, increased risk of subsequent carcinoma or recurrence of tumor after therapy. The aim of this study was to verify the existence of MACs in normal-appearing breast tissue adjacent to breast carcinoma. Image cytometry measurements were performed on 4-microns sections cut from formaldehyde-fixed tissue blocks and stained with thionin-SO2 following the Feulgen procedure. Morphologically normal appearing breast lobules were analyzed in patients with benign (20 cases) and malignant breast disease (23 invasive and 11 in situ tumors). The chromatin distribution features of the epithelial nuclei in normal-appearing breast lobules differed between patients with benign and malignant breast disease. Changes in nuclear features, detected in epithelial nuclei from normal-appearing lobules in breasts resected for carcinoma, were defined as MACs. The frequency of MAC nuclei was low in benign tissues, increased in tissues with ductal carcinoma in situ and highest in tissues with invasive carcinoma. Based on the measurements of nuclei in normal-appearing lobules, it was possible to discriminate between patients with benign breast disease and patients with invasive carcinoma in 86% of cases.

Breast↗

PubMed1995

Use of high-resolution cytometry in predicting the biologic behavior of T1 adenocarcinoma of the lung.

Touch preparations from 60 cases of T1 adenocarcinoma were analyzed using a high-resolution, automated image cytometer. These cases were divided according to pathologic stage: stage I, 31; stage II, 3; stage III, 19; and stage IV, 7. For each nucleus 57 features were analyzed, and using a linear combination of three texture features describing the DNA distribution in the cell nucleus (TARL, ODMAX and FAREA1), aggressive cancer cells belonging to stage III/IV could be identified. The best discrimination between the stages was achieved when the frequency of aggressive cancer cells was 48%; the correct classification rate was 77%. Using this criterion, 22 of 27 patients (81%) who died of cancer within five years after surgery were correctly predicted. These results suggest that high-resolution cytometry may be of value in predicting the biologic behavior of adenocarcinoma cases, especially in stage I/II.

Adenocarcinoma↗

PubMed1995

Histometric texture analysis of DNA in thin sections from breast biopsies. Application to the detection of malignancy-associated changes in carcinoma in situ.

OBJECTIVE: To evaluate histometric measurement of nuclear texture in breast biopsy sections in order to detect malignancy-associated changes in apparently normal tissue in the vicinity of carcinoma in situ. STUDY DESIGN: We previously showed that image cytometry measurements of nuclear features--foremost, texture features, describing the organization of Feulgenstained DNA in the cell--can be used to distinguish normal-appearing, diploid epithelial cells from patients with invasive carcinoma of the breast from those with benign biopsies. In that study, referred to as the "single cell analysis," images of at least 200 epithelial cells were acquired for each slide, and substantial user interaction was required to segment cells from each field. Location of isolated cells and interactive segmentation are both time-consuming procedures, particularly in breast tissue, where nuclei can be tightly clustered within a duct. With histometric texture analysis on the same specimens, segmentation of individual cells was ignored, and texture measurements were performed over the entire cluster of relevant cells. With this approach, ploidy information is not available, and touching and overlapping nuclei are included in the measurements. Measurement of histometric texture properties requires substantially less time (at least an order of magnitude) than individual cell measurement and, if ploidy information is not significant, may therefore provide a more practical means of analysis for tissue sections. RESULTS: Seventeen cases of invasive carcinoma and 17 cases of nonproliferative breast disease were examined. Using stepwise discriminant function analysis, slides were classified into one of the two groups with an accuracy of 88.6% in the case of single cell analysis and with an accuracy of 88.2% using histometric analysis. CONCLUSION: The existence of malignancy-associated changes in the breast was confirmed by an independent analysis of the same specimens. Although the two methods are not directly comparable, we found that histometric texture analysis performs at least as well as single-cell analysis for the detection of malignancy-associated changes in breast carcinoma.

Biopsy↗

PubMed1995

Malignancy associated changes in cervical smears: systematic changes in cytometric features with the grade of dysplasia.

For almost ten years. Malignancy Associated Changes have been consistently found by means of high resolution image analysis of apparently normal uterine cervix cells. The study was performed on normal intermediate cells randomly selected from 1850 cervical smear slides classified as negative, mild dysplasia, moderate dysplasia and severe dysplasia. Size and texture features, performed by the Cyto-Savant software, have shown significant monotonic changes with the grade of dysplasia. These findings indicate that the intensity of Malignancy Associated Changes are directly related to the severity of the adjacent lesions.

Cell Transformation, Neoplastic↗

PubMed1995

Nuclear texture measurements in image cytometry.

DNA image cytometry is widely used in cytopathology as a means to obtain objective information concerning the diagnosis and prognosis of human cancer. Using specially designed devices, the high resolution spatial and photometric information is available in the images of a microscopic field. If quantitative DNA specific stains are used the chromatin distribution in the cell nuclei can be measured, which is one of the critical features for cytopathological analysis. In normal cells, changes in the chromatin appearance reflect changes in the activation patterns of genes. In tumors, dramatic changes in the nuclear chromatin appearance are common and have been associated with the progression of the disease. Features describing the chromatin distribution pattern are referred to as texture features. Nuclear texture features are sensitive to the differences between the various descriptive classes of chromatin patterns. In this paper we discuss the main categories of nuclear texture measurements. Texture features can be roughly divided into the following categories: 1) descriptive statistics of chromatin distribution; 2) discrete texture features; 3) range extreme; 4) markovian; 5) run length and 6) fractal texture features. Representative features of each of the above categories are discussed together with mathematical formulas, simple figures for explanation as well as images of typical cells which differ significantly in some texture features. Key references are also provided.

Cell Nucleus↗

PubMed1994

Quantitative precision of an automated image cytometric system for the measurement of DNA content and distribution in cells labeled with fluorescent nucleic acid stains.

An automated image cytometric system is described for the measurement of DNA content and distribution in cells stained with fluorescent DNA binding or intercalating compounds. The quantitative precision of integrated optical intensity (IOI) measurements using this system was estimated to be 2.0%, based on the coefficient of variation (cv) of the IOI of DNA check beads. Using peripheral blood lymphocytes stained with 4'-6-diamidino-2-phenylindole (DAPI), the cv of IOI was found to be 3.5%. Slide to slide variability of the IOI for peripheral blood lymphocytes (cv over 10 slides of the mean IOI) was found to be 2%. The most important sources of error in these measurements were glare, illumination instability, image calibration instability, and staining non-uniformity. These errors were investigated and minimized.

DNA↗

PubMed1994

Effects of fixation method on image cytometric measurement of DNA content and distribution in cells stained for fluorescence with propidium iodide.

We performed image cytometric measurements of DNA content and distribution on cycling human HCT-8 cells stained for fluorescence with propidium iodide (PI). Seven different fixation protocols were evaluated for stoichiometry of PI staining and for their ability to preserve in vivo chromatin structure. Bimodal integrated optical intensity (IOI) histograms were obtained with all fixation protocols. Increased accessibility of DNA to the dye was evident in increased values of the IOI at the GI peak. The fixatives studied, in order of increasing accessibility to DNA, were Regaud's Boehm-Sprenger, Carnoy's, air-drying, methanol, ethanol, and acetone/methanol. In general, the coefficient of variation of the IOI within the G1 peak was higher for fixatives where DNA is less accessible. Features describing the spatial distribution of stain exhibited dramatic changes for Boehm-Sprenger fixation, which were consistent with the observation that in vivo conformation of chromatin is best preserved with this method.

Adenocarcinoma↗

PubMed1994

Nuclear texture: can it be used as a surrogate endpoint biomarker?

Nuclear texture measurements are suggested to predict the progression/regression of precancerous lesions in breast, cervix, lung, and possibly other tissues. Nuclear texture features describe DNA distribution patterns in cell nuclei, and can be reliably measured by high resolution image cytometry, both in tissue sections as well as in single cell preparations such as smears from fine needle aspirates (FNAs) or cell suspension preparations. The cells must be stained with a stoichiometric DNA stain. For absorbance staining, the Feulgen-Thionin stain is one of the best performers used for DNA ploidy measurements using conventional image cytometry. Regression/progression information can be obtained from either diagnostic cell nuclei or from cell nuclei of normal surrounding tissue. Subtle changes in normal-appearing cells adjacent to malignant tumors are called malignancy associated changes (MACs) and can be detected by nuclear texture measurements. We postulate that measurements of texture features can also be employed as surrogate endpoint biomarkers (SEBs).

Anticarcinogenic Agents↗