Biomedical subjects

A A Baky

Publications and source records attributed to A A Baky.

6 recordsLinked to original sources

PubMed1981

Nuclear boundary detection algorithm based on a minimax derivative statistic for atypical bronchial squamous epithelial cells.

The thresholding approach in scene segmentation of digitized cell images was found to be unreliable for use with squamous epithelial cells characterized by chromatin condensation within the nucleus. It was observed that the nuclear boundaries of such cells were visually distinguishable. An algorithm was developed for detecting nuclear boundaries in digitized cell images. This algorithm is based on a minimax derivative statistic that has maximum values at nuclear boundaries and low values elsewhere. The statistical properties of the confusion matrix of cellular scene segmentation are outlined. A measurement and a test statistic for scene segmentation errors based on those properties are presented.

Bronchi↗

PubMed1981

Image analysis of atypical bronchial squamous epithelial cells. A quantitative and qualitative examination of squamous cell carcinogenesis.

Atypical bronchial squamous epithelial cells from cigarette smokers were digitized using a high-resolution microphotometric scanning system operating at a wavelength of 530 nm. All cells used for the purpose of developing a training set as well as those used as a test set were classified by a team of three cytopathologists. Reduction in the dimensionality of the feature space and cell classification were performed using a new system known as the atypia status index (ASI); this dual-purpose system will specifically classify cells into five distinct classes of progressive atypia as well as quantitate the degree of atypicality of each individual cell. The distribution of cellular ASI values was arranged from lowest to highest and plotted for each subject as a profile. The ASI range has well-defined intervals, representing the five different atypia classes used in the study (squamous metaplasia, mild atypia, moderate atypia, severe atypia and carcinoma). Subjects at different stages of carcinogenesis were found to have significantly different profiles (P less than 0.01). Changes in visual morphologic characteristics and their relation to changes in ASI values for the five different classes of atypia are presented.

Bronchi↗

PubMed1980

Aytpia status index of respiratory cells: a measurement for the detection and monitoring of neoplastic changes in squamous cell carcinogenesis.

A statistical procedure was developed for calculating an atypia status index (ASI) for cells from the bronchial mucosa. These indices represent the degree of abnormal changes in these cells and classify them as squamous metaplasia, mild atypia, moderate atypia, servere atypia or carcinoma. The classification accuracy of the procedure was more than 99% on trained data and was accomplished by minimizing the overlapping areas between the adjacent multivariate distributions of cell groups for selected features whose group means represent a monotonic function and for which the cell categories are distinguishable. The calculated ASI may reflect abnormal changes in the cell that may not be clearly evident visually. It appears that progression or reversal of bronchial epithelial atypia can be accurately monitored by studying the changes in the ASI, not only for preneoplasia but also for reactions to chemotherapy and various pulmonary infectious disease processes, such as influenza.

Adult↗

PubMed1980

Cell atypia profiles for bronchial epithelial cells: mathematical evaluation of sputum cellular atypia in squamous cell carcinogenesis of the lung.

Atypical bronchial epithelial cells from the sputum of male cigarette smokers were digitized by scanning microphotometry and analyzed by computerized image analysis techniques. A set of specific analytic features based on cell morphology was extracted and combined mathematically to be expressed as a single number (Atypia Status Index). This index represented the stages of the cellular atypia (squamous metaplasia; mild, moderate or severe atypia; or carcinoma) quantiatively as a single number varying between 0.0 and 5.5 The Atypia Status Index for each cell correlated highly (94% to 99%) with visual cytopathologic classification. The distributions of cells according to their indices were profiled for patients at various stages of carcinogenesis and used to classify patients relative to their degree of cell atypia. These results compared favorable to those of the clinical evaluation.

Bronchi↗

PubMed1978

Effect of prehatching weightlessness on adult fish behavior in dynamic environments.

At 16-17 months of age, three groups of fish from the embryonated eggs in the ASTP killifish experiment were subjected to postflight tests consisting of rapidly changing environments. It was found that the group of fish with the least amount of development at orbital insertion (A-32) had a decreased rheotropism for both the moving background and the rotating water current tests when compared to ground control fish. Exposure to parabolic aircraft flight conditions revealed that the A-32 fish were less disoriented during zero gravity periods and were hypersensitive to high-gravity periods. These results suggested a modified vestibular competency due to a 9-d prehatching weightlessness exposure.

Adaptation, Physiological↗

PubMed1977

Behavioral analyses of killifish exposed to weightlessness in the Apollo-Soyuz test project.

Two groups of killifish, Fundulus heteroclitus, which were flown aboard Apollo-Soyuz, were subjected to postflight behavioral testing. The first group examined consisted of a graded series of embryos representing key developmental stages at orbital insertion (32-h, 66-h, and 128-h stages; pre-liftoff fertilization times). The tests revealed that the young adults from the flight 32-h stage had a significantly decreased positive geotaxis and increased negative phototaxis when compared with ground controls. These findings suggested a greater sensitization of the least-developed flight stage to post-hatching environmental influences. The second group consisted of 21-d old juveniles which were subjected to light orientation tests soon after recovery. No significant differences were detected.

Animals↗