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Biomedical subjects

L L Wheeless

Publications and source records attributed to L L Wheeless.

At least 55 records · Page 3Linked to original sources
PubMed1979

False alarms in a slit-scan flow system: causes and occurrence rates. Implications and potential solutions.

A slit-scan technique was developed as a basis for an automated prescreening system for gynecologic cytology. A flow system based on this technique was fabricated and tested and results indicated that false alarms (misclassification of objects or events from normal specimens as abnormal) are the greatest remaining obstacle to development of an automated prescreening instrument. A dual view correlation system was fabricated to provide exact image-contour correlation in flow and permit precise determination of causes and occurrence rates of false alarms. This paper presents data from correlation analyses of 23 normal cytologic specimens. Major causes of false alarms and their implications to automated prescreening are discussed. A technique that would eliminate the majority of false alarms in flow is presented.

Cervix Uteri↗
PubMed1979

Cytofluorometric and cytochemical comparisons of normal and abnormal human cells from the female genital tract.

Acridine orange staining of exfoliated cells from epithelial tissues facilitates discrimination between normal and abnormal cells: abnormal cells develop highly elevated nuclear fluorescence. Comparisons of acridine orange (AO) staining with propidium iodide (PI) or Feulgen staining have shown that: (a) PI staining also provides highly elevated nuclear fluorescence from abnormal cells; (b) the distributions of nuclear fluorescence following AO or PI staining were usually not significantly different as judged by the Kolmogorov-Smirnov test; (c) fluorescence emission spectra from AO and PI stained cells are consistent with the hypothesis that both fluorochromes bind to DNA within cell nuclei; (d) DNAse treatment of AO stained normal cells eliminates the nuclear fluorescence peak from slit-scan contours; RNAse treatment has no effect on nuclear fluorescence; (e) the distribution of abnormal cell nuclear fluorescence after AO staining is usually, but not always, significantly different from the distribution of abnormal cell nuclear absorbance after Feulgen staining, with relative nuclear fluorescence being greater than relative nuclear absorbance. The hypothesis currently most consistent with these results is that elevated Feulgen DNA content can account for only part of the discrimination provided by AO staining, and that the chromatin within abnormal cells is altered so as to increase accessibility of DNA to intercalating dyes.

Cell Nucleus↗
PubMed1978

A comparison of acridine orange and Feulgen cytochemistry of human tumor cell nuclei.

Specimens of cells derived from tumors of the human female genital tract plus normal cells as standards have been divided into aliquots and stained according to acridine orange or pararosanilin:Feulgen procedures. Acridine orange-stained cells were slit-scanned for 535 nm nuclear fluorescence; Feulgen-stained cells were comb-scanned for 580 nm nuclear absorbance. For each specimen examined, the tumor cell:normal cell ratio of mean nuclear fluorescence following acridine orange staining was greater than the tumor cell:normal cell ratio of mean nuclear absorbance following Feulgen staining. The tumor cell:normal cell ratio of mean nuclear fluorescence ranged from 2.3 for a nonkeratinizing squamous cell carcinoma to 3.9 for a keratinizing squamous cell carcinoma. The tumor cell:normal cell ratio of mean nuclear absorbance ranged from 1.4 for a mixed mesodermal sarcoma to 2.3 for a small cell squamous cell carcinoma. These results indicate that the elevated nuclear fluorescence intensity from acridine orange-stained tumor cells cannot be explained solely on the basis of elevated Feulgen:DNA content. An alternative hypothesis, consistent with these results, is that DNA is the principal binding substrate for intranuclear acridine orange and that the DNA of certain tumor cells is more accessible to acridine orange than is the DNA of normal cells.

Acridines↗
PubMed1977

Application of Fraunhofer diffraction theory to feature-specific detector design.

Light scatter from epithelial cells in a slit-scan flow system is modeled using the Fraunhofer condition of scalar diffraction theory. Power spectra are calculated for successive positions of model cells in the line focus of a laser beam with a Fourier transform computer program. Using the calculated power spectra, detector configurations are designed to detect specific cell structures of interest. Detector configurations are tested in a static slit-scan scatter apparatus. Data indicating the ability to detect boundaries and cell orientation are discussed.

Cell Nucleus↗
PubMed1977

Imaging systems for correlation of false alarms in flow.

False alarms, arising from a variety of sources, are the greatest remaining obstacle to development of an automated prescreening system for gynecologic cytology. This paper describes two correlation systems under development at the University of Rochester and discusses their utilization in the study of false alarms in slit-scan cytofluorometry. Both systems permit imaging of objects in flow and correlation between images and corresponding slit-scan contours. Correlation systems will permit a detailed study of false alarm causes and aid in the search for new features to assist in their recognition.

Autoanalysis↗
PubMed1976

Slit-scan cytofluorometry. Basis for automated prescreening of urinary tract cytology.

A study was undertaken to assess the applicability of the slit-scan technique to automated prescreening of urinary tract cytology. Cells from voided and catheterized urines were stained with acridine orange and measured on a static cell slit-scan cytofluorometer. Analysis of data from the specimens indicates that nuclear fluorescence alone appears adequate for recognition of abnormal specimens. Remaining problems in the automation of urinary tract cytology prescreening are discussed.

Autoanalysis↗
PubMed1976

Laser stroboscopic photography. Technique for cell orientation studies in flow.

Squamous cells in fluid flow are photographed using a laser stroboscopic technique. The technique provides either dark field or phase contrast multiple images of a cell on a single frame of film at resolutions permitted by the thickness of the cell stream. Cell orientation, velocity and acceleration are obtained from these photographs for evaluation of flow system performance.

Autoanalysis↗
PubMedDate not supplied

The binucleate cell: implications for automated cytopathology.

A study of occurrence rates of binucleate cells in human femal gynecological specimens is described. Data is presented on probability of occurrence, nuclear spacing, and nuclear fluorescence of binucleate cells. Allowable binucleate recognition error rates for automated cytopathology are presented. Recognition techniques employing slit-scan cytofluorometry are discussed.

Cell Count↗
PubMedDate not supplied

Syringing as a method of cell dispersal. I. Effect on intermediate and superficial squamous cells.

Mechanical shear in the form of syringing was applied to human gynecologic cytology specimens in an effort to disperse cell clumps. The percentage of single squamous cells achieved with the optimum conditions is generally 70 to 100 per cent. Syringing with a constant pressure device produces a high yield of single squamous cells without the concurrent high cell loss as often observed using enzymatic or chemical procedures. Data presented demonstrate that the slide preparation and clump evaluation procedures used for this study yield reliable and reproducible data. Studies varying stroke number and plunger pressure were completed and conditions for maximum dispersal were established.

Cell Separation↗
PubMedDate not supplied

Binucleate cell recognition in automated gynecologic cytopathology.

Medium resolution two dimensional image analysis techniques were applied to a large number of abnormal and binucleate cells from the uterine cervix. Techniques were developed for the extraction of nuclear boundary information from fluorescence images and two new nuclear shape descriptors were applied to the binucleate cell recognition problem. The descriptors were a contextual measure of concavity location and size on the nuclear boundary, and mean area of the two largest concavities. These features were superior both to total convex deficiency and to ratio of perimeter squared to area when applied to binucleate cell recognition. Classification based on the second feature, mean convex deficiency, provided lowest error rates. These were approximately 10% false positive and false negative single cells, and occurred with an effective two micron spot size. Higher false negative rates were observed with a one micron spot size.

Autoanalysis↗