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Ability to predict metastasis based on pathology findings and alterations in nuclear structure of normal-appearing and cancer peripheral zone epithelium in the prostate.

PURPOSE: Malignant transformation in the prostate produces significant alterations in glandular architecture (Gleason grade) and nuclear structure that provide valuable prognostic information. Normal-appearing nuclei (NN) adjacent to cancer may also have altered functions in response to malignancy. We studied NN adjacent to peripheral zone (PZ) prostate cancer (PCa), as well as the PZ cancer nuclei (CaN) using quantitative image cytometry. The nuclear structure information was combined with routine pathological findings to predict metastatic PCa progression and/or death. EXPERIMENTAL DESIGN: Tissue microarrays of normal-appearing and cancer areas were prepared from 182 pathologist-selected paraffin blocks. Feulgen-stained CaN and NN were captured from the tissue microarrays using the AutoCyte Pathology Workstation. Multivariate logistic regression was used to calculate quantitative nuclear grade (QNG) solutions based on nuclear morphometric descriptors determined from NN and CaN. Multivariate logistic regression and Kaplan-Meier plots were also used to predict risk for distant metastasis and/or PCa-specific death using QNG solutions and routine pathology. RESULTS: The pathology model yielded an area under the receiver operator characteristic curve of 72.5%. The QNG-NN and QNG-CaN solutions yielded an area under the receiver operator characteristic curve of 81.6 and 79.9%, respectively, but used different sets of nuclear morphometric descriptors. Kaplan-Meier plots for the pathology variables, the QNG-NN and QNG-CaN solutions, were combined with pathology to defined three statistically significantly distinct risk groups for distant metastasis and/or death (P < 0.0001). CONCLUSIONS: Alterations in cancer or normal-appearing nuclei adjacent to peripheral zone cancer areas can predict PCa progression and/or death. The QNG-NN and QNG-CA solutions could be combined with pathology variables to improve the prediction of distant metastasis.

Adult↗

Telomerase activity in touch-imprint cell preparations from fresh prostate needle biopsy specimens.

OBJECTIVE: To evaluate whether it is possible to detect telomerase activity in cells exfoliated from prostate biopsies immediately before fixation. METHODS: A total of 115 transrectal biopsies of prostate tissue from 49 patients were touch-imprinted on an RNase-free microscope slide and then fixed. Touch imprints were immediately frozen and used to extract telomerase. Telomerase activity was determined by a telomeric repeat amplification protocol (TRAP) using a PCR-ELISA method. Inflammation and epithelial cells in each biopsy were quantitated by image cytometry. RESULTS: A total of 90/115 extracts had a proteic content suitable for analysis. Telomerase activity was detected in 18/26 (70%) carcinomas, 2/9 (22%) low-grade prostatic intraepithelial neoplasia (PIN) lesions, and 1/3 (33%) high-grade PIN lesions. In 4 of 7 patients with telomerase-positive tumors, telomerase activity was also found in a distant site devoid of morphologically detectable cancer cells. Telomerase activity was detected in touch imprints from fragments with less than 1 mm(2) of epithelial tissue, and was not associated with the extent of inflammation. CONCLUSIONS: From the technical stand point, the touch-imprint method may provide a useful adjunct for telomerase detection in prostate biopsies. With this procedure the bioptic fragment is left intact for histological examination. Diagnostically, the presence of telomerase activity in sites distant from the original tumor might suggest the presence of tumor cells that are morphologically undetectable.

Aged↗

Analysis of minimal sample volumes from head and neck cancer by laser scanning cytometry.

BACKGROUND: The increasing diversity in therapeutic strategies in head and neck oncology is dependent on the development of equally appropriate diagnostic tools. A growing number of diagnostic procedures is intended to be performed on an out-patient basis. In this context, analyses of hypocellular specimens such as fine-needle aspirate biopsies (FNABs) or swabs are very important: There are minimal side-effects, and they can be analysed within hours. MATERIAL AND METHODS: Laser scanning microscopy (LSC) is a microscope-based method combining the advantages of flow cytometry and image analysis: In addition to the fluorescence data of each individual cell, its morphology can be documented by re-staining with a conventional cytological staining. Any cell can then be re-localised in the microscope for direct observation. FNABs and swabs are incubated in PBS, erythrocytes are lysed, and cells are mounted on slides. After fixation in ethanol, cells are stained for cytokeratin by indirect immunolabelling and for DNA by propidium iodide. Analysis by LSC is performed to determine the ploidy of the epithelial cells. For immunophenotyping of peripheral blood in cancer patients by LSC 20 microl full blood are stained for CD antigens by direct immunolabelling and for DNA by 7-aminoactinomycin D. RESULTS: FNABs and swabs were taken from 150 malignancies of different sites in total; all specimens yielded sufficient cells (>5,000). 30 tumours of the parotid gland were analysed in detail: Out of 9 malignant tumours 8 showed aneuploidy, whereas all 21 benign tumours were diploid. Immunophenotyping in 23 tumour patients showed a significant reduction of lymphocytes in the peripheral blood as compared to healthy individuals. CONCLUSIONS: Further studies have to be performed to validate the analysis of hypocellular specimens by LSC and to determine its role in routine clinical work. Its potential is most evident in tumours that are not accessible for open biopsy such as those of the parotid gland or the larynx.

Antigens, CD↗

Response to chemotherapy (irinotecan plus 5-fluorouracil) in colorectal carcinoma can be predicted by tumour DNA content.

OBJECTIVE: The aim of this study was to identify markers that might predict response to chemotherapy. Postoperative chemotherapy improves the outcome in stage III colon cancer and is widely accepted as a standard therapy, but there are currently no reliable predictors to identify and select patients that will benefit. METHODS: Using DNA image cytometry, the DNA content was determined from the isolated nuclei of 56 primary colorectal carcinomas of patients who received chemotherapy (either irinotecan or irinotecan plus 5-fluorouracil and folinic acid) for advanced disease. Response to chemotherapy could be reliably evaluated in 53 patients. RESULTS: The modal DNA content (ploidy status) of the tumour correlated with the observed response to chemotherapy (p = 0.01). An objective response was observed in 56% of patients whose tumour histograms displayed tetraploid, peri-tetraploid or multiploid patterns of peaks, compared with 19% in patients with diploid, peri-diploid or aneuploid peaks. Notably, 86% (6/7) of patients whose tumours displayed a multiploid peak pattern showed an objective response and 1 patient had stable disease. CONCLUSIONS: This study suggests that modal DNA content can be used to predict a patient's response to chemotherapy in advanced colorectal carcinoma. This may help in identifying patients who will benefit most from therapy for advanced colorectal cancer.

Adult↗

Value of quantitative DNA analysis in endocrine tumors of the pancreas.

BACKGROUND: The diagnosis of malignancy can be difficult in endocrine tumors of the pancreas. Moreover prognostically relevant factors are not available. The aim of this study was to evaluate retrospectively whether the DNA distribution pattern can differentiate between benign and malignant pancreatic endocrine tumors and secondly whether the DNA content of tumor cells gives prognostic information. METHOD: Image cytometry of paraffin-embedded tumor material of 42 pancreatic endocrine tumors. RESULTS: In 27 benign endocrine pancreatic tumors (25 insulinomas, 2 benign nonfunctioning endocrine tumors) we could differentiate between 6 diploid, 15 hypotriploid and 6 triploid DNA histograms. In 15 malignant endocrine tumors of the pancreas we could differentiate between 1 diploid, 1 hypotriploid, 9 triploid and 4 hypertriploid tumors. All 4 patients with a hypertriploid tumor died as a consequence of their disease in contrast to only 1 patient with a diploid, hypotriploid or triploid tumor even in case of a nonradical resection. CONCLUSION: With the help of quantitative DNA measurement a differentiation between malignant and benign endocrine pancreatic tumors is not possible even if the risk of malignancy increases with the DNA content. The DNA content of malignant endocrine pancreatic tumors has an influence on the long-term survival. Hypertriploid tumors have a statistically significantly worse prognosis than diploid, hypotriploid or triploid tumors.

Adenoma↗

Digital imagery/telecytology. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.

ISSUES: Optical digital imaging and its related technologies have applications in cytopathology that encompass training and education, image analysis, diagnosis, report documentation and archiving, and telecommunications. Telecytology involves the use of telecommunications to transmit cytology images for the purposes of diagnosis, consultation or education. This working paper provides a mainly informational overview of optical digital imaging and summarizes current technologic resources and applications and some of the ethical and legal implications of the use of these new technologies in cytopathology. CONSENSUS POSITION: Computer hardware standards for optical digital imagery will continue to be driven mainly by commercial interests and nonmedical imperatives, but professional organizations can play a valuable role in developing recommendations or standards for digital image sampling, documentation, archiving, authenticity safeguards and teleconsultation protocols; in addressing patient confidentiality and ethical, legal and informed consent issues; and in providing support for quality assurance and standardization of digital image-based testing. There is some evidence that high levels of accuracy for telepathology diagnosis can be achieved using existing dynamic systems, which may also be applicable to telecytology consultation. Static systems for both telepathology and telecytology, which have the advantage of considerably lower cost, appear to have lower levels of accuracy. Laboratories that maintain digital image databases should adopt practices and protocols that ensure patient confidentiality. Individuals participating in telecommunication of digital images for diagnosis should be properly qualified, meet licensing requirements and use procedures that protect patient confidentiality. Such individuals should be cognizant of the limitations of the technology and employ quality assurance practices that ensure the validity and accuracy of each consultation. Even in an informal teleconsultation setting one should define the extent of participation and be mindful of potential malpractice liability. ONGOING ISSUES: Digital imagery applications will continue to present new opportunities and challenges. Position papers such as this are directed toward assisting the profession to stay informed and in control of these applications in the laboratory. Telecytology is an area in particular need of studies of good quality to provide data on factors affecting accuracy. New technologic approaches to addressing the issue of selective sampling in static image consultation are needed. The use of artificial intelligence software as an adjunct to enhance the accuracy and reproducibility of cytologic diagnosis of digital images in routine and consultation settings deserves to be pursued. Other telecytology-related issues that require clarification and the adoption of workable guidelines include interstate licensure and protocols to define malpractice liability.

Computer Communication Networks↗

Rescreen effect in conventional and PAPNET screening: observed in a study using material enriched with positive smears.

OBJECTIVE: To study the rescreen and PAPNET effects on enriched material derived from smears screened routinely using PAPNET and conventional microscopy. STUDY DESIGN: A series of 432 smears (containing 122 atypical squamous cells of undetermined significance [ASCUS] plus 44 at least dysplastic squamous intraepithelial lesion-positive [SIL+] ones), screened routinely with the conventional method, were rescreened using the PAPNET system. Another series of 461 smears (containing 140 ASCUS + 52 SIL+ ones) screened routinely with PAPNET were rescreened conventionally. The rescreen effect, defined as the effect of differences between the rescreen and routine screening situation, was investigated by comparing the rescreen results in both series of smears with the routine results in both series. The effect of using either method of screening was studied by comparing the PAPNET results in both series with the results of conventional screening in both series. RESULTS: The rescreen effect was statistically significant both for a higher number of smears classified as negative (less than ASCUS) and a higher number of smears classified as high grade SIL or more. PAPNET-assisted screening resulted in a significantly higher number of smears classified as high grade SIL+, although for this latter finding there is an unexplained significant difference between conventional and PAPNET-screened cases in the changes made by the cytopathologist in the cytotechnologists' diagnoses. CONCLUSION: The rescreen effect should not be ignored when enriched material is used.

Carcinoma, Squamous Cell↗

Multiparameter absorption measurements in automated microscopy. Simultaneous quantitative determination of DNA and nuclear antigen.

OBJECTIVE: To test a dual DNA-nuclear antigen staining method for multiparameter absorption image analysis. STUDY DESIGN: MCF 7 cells, grown on glass slides, served as a model to test the staining technique. For DNA, Feulgen-based CAS quantitative DNA staining, and for nuclear antigen, alkaline phosphatase-based immunocytochemical staining with CAS Red as the chromogen, were used. MIB-1, estrogen and progesterone receptors were used as examples of nuclear antigen staining. Measurements were performed with the DISCOVERY image analyzer. RESULTS: Scatterplots, in which the nuclear antigen content was plotted against the DNA content, were obtained. Immunostain-positive and -negative populations could be discriminated. These cells were visualized in image galleries. The DNA histograms of the positive and negative cells showed no change in coefficient of variation or integrated optical density ratio of the G0, G1 and G2 + M peaks as compared to single DNA staining. The intensity of the immunostain increased as compared to the single immunostaining result. CONCLUSION: This staining technique allows the simultaneous accurate measurement of costained DNA and antigen within the same nucleus. This opens the possibility for studies in which nuclear antigen expression is monitored during the cell cycle or in cells of different ploidy classes. Identified cells can also be visualized by presentation in an image gallery or by relocation on the slide. This can support the analysis of clinical samples, where cytometric data can be correlated with and confirmed by visual diagnosis.

Adenocarcinoma↗

Cytomorphologic and DNA cytometric features of hepatocellular carcinoma in fine needle aspirates.

OBJECTIVE: To classify hepatocellular carcinoma according to DNA ploidy patterns and to evaluate distinct cytomorphologic features of hepatocellular carcinoma that correlate with DNA ploidy patterns. STUDY DESIGN: Fine needle aspiration smears of 36 histologically proven hepatocellular carcinomas were performed for DNA measurement by image analysis after Feulgen restaining of the specimens. Nuclear features-prominent nucleoli, nuclear cleavage, nuclear area and nuclear/cytoplasmic ratio-were correlated with the DNA ploidy patterns. RESULTS: Of the 36 cases, 14 were either diploid (n = 7) or polyploid (n = 7), 19 tumors had a single aneuploid stemline, 2 cases had multiple stemlines, and 1 case had no discernible stemline. A preponderance of prominent nucleoli was seen in 7/7 diploid tumors (2c), 6/7 polyploid tumors (4c, 8c) and 6/8 aneuploid tumors (> 4c). Conspicuous nuclear cleavage in a high number of tumor cells was present substantially in tumors with large nuclear areas (4c, > 4c). CONCLUSION: Most hepatocellular carcinoma studied had a distinct stemline so that the tumors could be designated DNA diploid, polyploid or aneuploid. The prevalence of prominent nucleoli and nuclear cleavage was a distinguishing cytologic feature that could predict DNA ploidy patterns. No special association of the nuclear/cytoplasmic ratio with any of the ploidy groups was noted.

Aneuploidy↗

P53 protein expression and DNA ploidy in common epithelial tumors of the ovary.

OBJECTIVE: To investigate p53 protein expression and DNA content in imprints from surgical biopsies of common epithelial tumors of the ovary. STUDY DESIGN: The study was based on 60 cases of epithelial tumors of the ovary (15 benign, 3 border-line and 42 malignant). For the demonstration of p53 protein, immunocytochemical staining with the avidin-extravidin technique was performed using monoclonal antibody p53 DO-7. DNA content was measured by image cytometry after Feulgen staining. RESULTS: There was a strong correlation between p53 expression and aneuploidy, with the difference between diploid and aneuploid tumors statistically significant (P < .001). A correlation was found between DNA ploidy, histologic grade and clinical stage (P < .001 and P < .05), respectively. There was no correlation between DNA ploidy and histologic type (P = .89). No correlation was observed between p53 protein expression and grade or clinical stage of the tumors. Nevertheless, a correlation of p53 expression between early (I, II) and advanced stages (III, IV) (P < .05) was observed. All benign and borderline tumors were diploid and did not express p53 protein. CONCLUSION: The results of the present study and the data in the literature stress the value of p53 expression and DNA ploidy in assessing the malignant potential of common epithelial ovarian cancers. However, the clinical application of these data requires further study.

Aneuploidy↗

Novel cell imaging techniques show induction of apoptosis and proliferation in mesothelial cells by asbestos.

We developed in situ dual-fluorescence detection techniques for measuring apoptosis and proliferation simultaneously in single dishes of cells. The deoxyribonucleic acid (DNA)-specific labeling method, terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate nick-end labeling (TUNEL), first was used in conjunction with a 4',6-diamidino-2-phenylindole (DAPI) counterstain to detect and measure morphologic characteristics of apoptotic rat pleural mesothelial (RPM) cells isolated from Fischer 344 rats and exposed to 300 microM hydrogen peroxide (H2O2). For this purpose, 100 TUNEL-positive nuclei were measured while being viewed with DAPI counterstaining for area, perimeter, longest diameter, and average diameter, using imaging software and an image-collection apparatus. We then exposed cells to a range of concentrations of crocidolite asbestos and putative apoptotic and mitogenic agents. Exposure to crocidolite asbestos (5 microg/cm2) caused a striking dose-dependent apoptotic response at 24 h, 48 h, and 72 h. The nonfibrous crocidolite analogue riebeckite failed to induce apoptosis. At 24 h, tumor necrosis factor-alpha (TNF-alpha) (10 ng/ml) caused an increase in apoptotic nuclei. A second method, utilizing an antibody to 5'-bromodeoxyridine (BrdU) and oxazole yellow homodimer (YOYO), showed a dose-dependent increase in proliferation occurring in cells exposed to asbestos (5 microg/cm2) at 48 h and 72 h. In addition, increased numbers of rat pleural mesothelial (RPM) cells exposed to 12-O-tetradecanoylphorbol-13-acetate (TPA), TNF-alpha, and epidermal growth factor (EGF) exhibited incorporation of BrdU at these time points, although total numbers of cells per unit area were unchanged. Results indicate a dynamic balance between apoptosis and increased DNA synthesis after exposure of mesothelial cells to asbestos.

Animals↗

Quantification of viability in organotypic multicellular spheroids of human malignant glioma using lactate dehydrogenase activity: a rapid and reliable automated assay.

Organotypic spheroids from malignant glioma resemble the biological complexity of the original tumor and are therefore appealing to study anticancer drug responses. Accurate and reproducible quantification of response effect has been lacking to determine drug responses in this three-dimensional tumor model. Lactate dehydrogenase (LDH) activity was demonstrated in cryostat sections of spheroids using the tetrazolium salt method. Calibrated digital image acquisition of the stained cryostat sections enables quantification of LDH activity. Fully automated image cytometry reliably demarcates LDH-active and LDH-inactive tissue areas by thresholding at specific absorbance values. The viability index (VI) was calculated as ratio of LDH-active areas and total spheroid tissue areas. Duplicate staining and processing on the same tissue showed good correlation and therefore reproducibility. Sodium azide incubation of spheroids induced reduction in VI to almost zero. We conclude that quantification of viability in cryostat sections of organotypic multicellular spheroids from malignant glioma can be performed reliably and reproducibly with this approach.

Aged↗

Effects of parenteral nutrition support and chemotherapy on the phasic composition of tumor cells in gastrointestinal cancer.

BACKGROUND: Some clinical studies report the effects of parenteral nutrition in malnourished cancer patients, but few discuss the tumor response to parenteral nutrition plus chemotherapy. If used in combination, the antitumor activity of chemotherapeutic agents may compensate for the tumor stimulation of parenteral nutrition. METHODS: Ninety-two patients with operable gastrointestinal cancer and malnutrition were randomly assigned to four interventions that were administered for 7 days preoperatively: parenteral nutrition alone, parenteral nutrition plus chemotherapy, chemotherapy alone, or no treatment (control). The preintervention and postintervention DNA content, DNA index, percentage of cells in S phase, and tumor cell sensitivity to chemotherapy were measured using image cytometry. RESULTS: Parenteral nutrition resulted in a significant proliferation of tumor cells and a significant increase in the sensitivity of tumor cells to chemotherapy; these effects were not seen in tumors of patients receiving parenteral nutrition plus chemotherapy. There was, however, a nonsignificant increase in tumor cell proliferation and sensitivity to chemotherapy in the tumors of subjects receiving combined therapy compared with those of subjects who received chemotherapy alone. The postintervention nutritional status of both the parenteral nutrition group and the parenteral nutrition plus chemotherapy group were significantly better than that of the control group and the chemotherapy group. The short-term, postoperative clinical outcomes in the chemotherapy group were significantly worse than those in the other three groups. CONCLUSIONS: These results indicate that combining chemotherapy and nutrition support preoperatively for malnourished patients with gastrointestinal cancer improves short-term nutritional status without increasing the proliferation of tumor cells and prevents the postoperative complications that occur when such patients are given chemotherapy without nutrition support. The results also suggest--but do not prove--that parenteral nutrition may increase the effectiveness of chemotherapy in malnourished patients.

Adult↗

Increased nuclear ploidy, not cell proliferation, is sustained in the peroxisome proliferator-treated rat liver.

Peroxisome proliferators are believed to induce liver tumors in rodents due to sustained increase in cell proliferation and oxidative stress resulting from the induction of peroxisomal enzymes. The objective of this study was to conduct a sequential analysis of the early changes in cell-cycle kinetics and the dynamics of rat liver DNA synthesis after treatment with a peroxisome proliferator. Immunofluorescent detection of proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine (BrdU) incorporation into DNA during S phase we used to assess rat hepatocyte proliferation in vivo during dietary administration of Wy-14,643, a known peroxisome proliferator and hepatocarcinogen in rodents. Rats were placed on diet containing 0.1% WY-14,643 and implanted subcutaneously with 5-bromo-2'deoxyuridine containing osmotic pumps 4 days prior to being sacrificed on days 4, 11, and 25 of treatment. Isolated liver nuclei labeled with fluorscein isothiocyanate (FITC)-anti-BrdU/PI and FITC-anti-PCNA/PI were analyzed for S-phase kinetics using flow cytometry. Morphometric analysis was performed to evaluate nuclear and cell size and enumeration of BrdU labeled cells, binucleated hepatocytes, and mitotic index. The BrdU labeling index increased 2-fold in livers of Wy-14,643-treated rats at day 4, but distribution of cells in G1, S phase, and G2-M did not differ significantly from controls. PCNA-positive cells decreased from 36% on day 4 to 17% on day 25, whereas the percentage of PCNA-positive cells in controls increased 2-fold from day 4 to day 11 and remained unchanged up to day 25. The differences in the number of PCNA-positive nuclei between control and Wy-14,643-treated groups were statistically significant only on day 4. Binucleated hepatocytes, determined by morphometric analysis, increased slightly on day 25 in treated rats parallel to an increase in the percentage of cells in G2-M phase. Significant shifts were noted in nuclear diameter and nuclear area after 11 and 25 days of treatment with Wy-14,643. Hepatic cell populations with nuclei > 9 microns diameter and nuclear area > 64 microns2 increased in Wy-14,643-fed rats during the treatment period compared with the control, indicating hepatic karyomegaly and hyperploidy, whereas percentage of distribution of nuclei based on diameter and area remained consistently unchanged in control animals from 4 through 25 days of sham treatment. The flow cytometric and morphometric analysis indicated an initial wave of DNA synthesis in response to Wy-14,643. The hepatomegaly was sustained over the treatment period accompanied by increase in ploidy with a significant shift toward hyperploidic hepatocytes. The increase in DNA content was almost entirely accounted for by the overall polypoidy increase rather than by an absolute increase in cells.

Animals↗

Atypical adenomatous hyperplasia (adenosis) of the prostate: DNA ploidy analysis and immunophenotype.

Atypical adenomatous hyperplasia (AAH) of the prostate is a microscopic proliferation of small acini that may be mistaken for adenocarcinoma. Although some data suggest that AAH is associated with adenocarcinoma arising in the transition zone, the clinical significance of this lesion is uncertain. Therefore we studied the DNA ploidy pattern and immunophenotype of AAH as compared with nodular hyperplasia and well-differentiated adenocarcinoma in 23 formalin-fixed, paraffin-embedded, whole-mounted retropubic prostatectomies. Representative sections were immunostained for keratin 34beta-E12, chromogranin, bcl-2, c-erbB-2, ki67-MIB1, and factor VIII (microvessel density). DNA ploidy was determined by image analysis and Feulgen-stained sections. There were rare scattered immunoreactive cells for chromogranin, bcl-2, and c-erbB-2 in nodular hyperplasia and AAH (mainly in the basal cell compartment) and in carcinoma. The ki67-MIB1 labeling index was different between nodular hyperplasia and AAH (p<0.001) and carcinoma (p=0.003) but not between AAH and carcinoma (p=0.203). Microvessel density was different between AAH and carcinoma (p=0.001) but not between nodular hyperplasia and AAH (p=0.105) or carcinoma (p=0.0820). All foci of nodular hyperplasia, AAH, and carcinoma were diploid. Ploidy status and our selected panel of antibodies did not discriminate among these 3 entities reliably.

Adenocarcinoma↗

Comparison of a visual to a computer-assisted technique for detecting apoptosis.

In many studies, fluorescent dyes (ethidium bromide [EB] and acridine orange [AO]) are used to stain DNA to determine if nuclei are apoptotic. However, there are numerous visual methods for counting these stained DNA that may lead to inaccuracies Measuring apoptosis by the visual counting method may be imprecise because of the variability of individuals' perception of color. Therefore, the authors compared a visual method of counting chromatin for apoptosis with a method relying on a computer program. They began counting chromatin using the visual method, in which individuals identify the stained DNA using their own visual perception. For comparison, they used a software-based counting method (analySIS software) to determine the color (hue) of the stained DNA. Using the numeric hue values from the software eliminates the variations in human color perception. Intra and interrater reliability of the visual and computer-assisted counting methods were evaluated with Spearman's. The authors found statistical significance in the intrarater reliability (r = 1.0, P = 0.0001 for all chromatin categories) and interrater reliability (r = 0.975, P = 0.005 for both readings) when using the software program. No statistical significance was found for the visual counting method, indicating inaccuracy between and within raters. Thus, the computer-assisted counting method of identifying the damaged DNA is more accurate and precise than the individual's visual perception of color. Based on these data, apoptosis measurements using color staining with EB and AO should be determined using hue values generated by a computer program and not by a researcher's visual assessment.

Acridine Orange↗

A new method to detect apoptosis in paraffin sections: in situ end-labeling of fragmented DNA.

Apoptosis (programmed cell death) can be difficult to detect in routine histological sections. Since extensive DNA fragmentation is an important characteristic of this process, visualization of DNA breaks could greatly facilitate the identification of apoptotic cells. We describe a new staining method for formalin-fixed, paraffin-embedded tissue sections that involves an in situ end-labeling (ISEL) procedure. After protease treatment to permeate the tissue sections, biotinylated nucleotides are in situ incorporated into DNA breaks by polymerase and subsequently stained with DAB via peroxidase-conjugated avidin. Staining of cells with the morphological characteristics of apoptosis was demonstrated in tissues known to exhibit programmed cell death, i.e., prostate and uterus after castration, tumors, lymph node follicles, and embryos. Apoptotic cells could be discriminated morphologically from areas of labeled necrotic cells, in which DNA degradation also occurs. Because apoptosis is relatively easily recognized in H&E-stained sections of involuting prostates of castrated rats, we used this model system to validate the ISEL method for the quantification of apoptotic cells. A high correlation was found between the fractions of ISEL-labeled cells and the fractions of apoptotic cells that were morphologically determined in adjacent sections. We conclude that ISEL is a useful technique for quantification of apoptosis in paraffin sections, especially for those tissues in which morphological determination is difficult. Furthermore, this new staining method enables the use of automated image cytometry for evaluating apoptosis.

Animals↗

Exploring issues of quality of service in a Next Generation Internet testbed: a case study using PathMaster.

This case study describes a project that explores issues of quality of service (QoS) relevant to the next-generation Internet (NGI), using the PathMaster application in a testbed environment. PathMaster is a prototype computer system that analyzes digitized cell images from cytology specimens and compares those images against an image database, returning a ranked set of "similar" cell images from the database. To perform NGI testbed evaluations, we used a cluster of nine parallel computation workstations configured as three subclusters using Cisco routers. This architecture provides a local "simulated Internet" in which we explored the following QoS strategies: (1) first-in-first-out queuing, (2) priority queuing, (3) weighted fair queuing, (4) weighted random early detection, and (5) traffic shaping. The study describes the results of using these strategies with a distributed version of the PathMaster system in the presence of different amounts of competing network traffic and discusses certain of the issues that arise. The goal of the study is to help introduce NGI QoS issues to the Medical Informatics community and to use the PathMaster NGI testbed to illustrate concretely certain of the QoS issues that arise.

Cell Biology↗