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Biomedical subjects

G Zajicek

Publications and source records attributed to G Zajicek.

At least 109 records · Page 6Linked to original sources
PubMed1984

Discrimination between normal and malignant gastric epithelial cells by computer image analysis.

The nuclei of 21 normal and 23 malignant epithelial cells from gastric smears obtained by brushing were analyzed by a black-and-white video camera under computer control. Each nucleus was digitized and its relief smoothed and displayed. A Sobel operator determined the nuclear boundaries and nuclear core area. Eighteen nuclear parameters (form descriptors and gray-value descriptors) were extracted for each nucleus and used as variables for discriminant analysis. Nine of these parameters proved useful for discrimination between normal and malignant gastric epithelial cells, with a correct classification rate of 100%. Of these, the best discriminating variables were the maximal gray value in the core, the maximal horizontal and vertical diameters, the core area and the mean derivative value in the core.

Cell Nucleus↗
PubMed1983

On the classification of nucleated red blood cells.

Bone marrow smears stained with Giemsa were scanned with a video camera under computer control. Red cells (89 normal and 44 megaloblastic) were sampled. Each cell was digitized into 70 X 70 pixels, each pixel representing a square area of 0.04 micron 2 in the original image. The pixel gray values ranged between 0-255. Zero stood for white and 255 represented black, while the numbers in between stood for the various shades of gray. The cells were first classified into six distinct classes, each representing a red blood cell differentiation state. The canonical discrimination functions derived from this classification were then utilized for grading cell differences in a continuous fashion. Each canonical discrimination function is represented in this multidimensional space by an orthogonal axis. The distance between two points (or cells) reflects their degree of similarity. By relating this measure to a reference state, it is possible to quantitate red blood cell differentiation changes. This approach is applicable to any differentiating tissue.

Anemia, Megaloblastic↗
PubMed1983

Image analysis of nucleated red blood cells.

Bone marrow smears stained with Giemsa were scanned with a video camera under computer control. Forty-two cells representing the six differentiation classes of the red bone marrow were sampled. Each cell was digitized into 70 X 70 pixels, each pixel representing a square area of 0.4 micron2 in the original image. The pixel gray values ranged between 0 and 255. Zero stood for white, 255 represented black, while the numbers in between stood for the various shades of gray. After separation and smoothing the images were processed with a Sobel operator outlining the points of steepest gray level change in the cell. These points constitute a closed curve denominated as inner cell boundary, separating the cell into an inner and an outer region. Two types of features were extracted from each cell: form features, e.g., area and length, and gray level features. Twenty-two features were tested for their discriminative merit. After selecting 16, the discriminant analysis program classified correctly all 42 cells into the 6 classes.

Azure Stains↗
PubMed1983

On the improving chances of the cancer patient.

The cancer hazard rate (or force of mortality) of all cancer survival curves of the 4th Report on End Results in Cancer, continuously declines. This pattern recurs also in breast cancer patients refusing treatment. The declining hazard rate is most conspicuous in Cancer and much less pronounced in other chronic diseases. In most of them the hazard rate actually increases. Such is obvious in any actuarial life table, in which the rising pattern represents aging and will therefore be denominated herewith as Aging pattern. It accompanies also many chronic diseases e.g. diabetes, following operation for peptic ulcer, young survivors from coronary occlusion, or cirrhosis. The cancer hazard rate exhibits a trend observable during regeneration and is viewed here to reflect a regenerative process operating in cancer which is ascribed to Neoplasia.

Age Factors↗
PubMed1982

Vascular turnover of a continuously growing organ: the rat incisor.

The vascular tissue supplying the pulp of the continuously growing and developing rat incisor was quantitatively analyzed in six female rats, weighing approximately 200 gm each. One hour after a single administration of 3H-TdR, 1 microCi/gm body weight, the rats were sacrificed and the lower left jaws excised and processed histologically. Every 20th section was evaluated for venular and arterial count, endothelial cell count, and percentage of labeled endothelial cells. It was found that the proliferative capacity of the vascular tissue of the rat incisor is confined to its most apical 3.0 mm-a zone defined as the vascular progenitor compartment. Daily production of endothelial vein cells and of veins within the progenitor compartment were calculated to be 7,392 cells/day and two veins/day, respectively. Generation time of these cells was found to be 3.56 days. Endothelial cell production within the progenitor compartment provides for the formation of new vessels and for the enlargement and elongation of existing ones. The vessels originating within the progenitor compartment move in an incisal and centripetal direction, while simultaneously undergoing a continuous process of aging, until their ultimate disintegration.

Animals↗
PubMed1982

The incubation time of cancer.

Incubation times of cancers whose initiation can be estimated relatively, precisely are distributed log-normally. This distribution is associated with a biphasic risk function, initially climbing to decline again after a certain period. A declining risk of contracting cancer implies further that the patient's chances of withstanding cancer improve with time. A similar declining risk function was also observed in age specific cancer incidence curves. At the age of 30 years they all rise exponentially to level off at old age. In some cancers e.g. bronchial or female genital, the curves even decline. The risk functions associated with them follow a similar course. Such may not be the case in some chronic systemic diseases, e.g. arteriosclerosis, in which the risk function never declines so that the patient's resistance to this disease is smaller than that observed in cancer. The declining risk proceeds even during the clinical phase of cancer as evident from two sources o data 1. Age specific cancer mortality curves exhibit the same pattern associated with a biphasic risk function and, 2. survival curves of cancer patients inhibit a declining risk function. The mounting resistance with time observed in cancer is observable in any disease, infectious as well chronic systemic.

Adult↗
PubMed1982

On the inadequacy of the concept of disease.

A framework for a critical examination of the disease concept is presented. The human organism is regarded as a complex system upon which certain hierarchies are imposed. The cell is regarded in this framework as the lowest hierarchy. Cells are aggregated into tissues and tissues into organs. Organs are assembled into organ systems constituting the human organism. The elementary indivisible unit in each hierarchy is called the HOLON. When viewed from the hierarchy below it encompasses a continuum. The holon is defined by its attributes. Its STATE represents the magnitudes of its attributes. The state of the organism is defined by the states of its holons. For each attribute a criterion level (or state) defines its ILLNESS STATE. ILLNESS is defined by the set of attributes crossing the criterion level. These attributes are divided into two two sets: Attributes requiring treatment by the physician and those not requiring intervention by him. The first is defined as DISEASE, while the second as the VIS MEDICATRIX NATURAE. THERAPY is the restoration of "ill" attributes below their criterion levels. The process of selecting the DISEASE attribute set from all organismic attributes is called DIAGNOSIS. The correctness of a diagnosis is testable by treatment results. A successful treatment corroborates the diagnosis and vice versa. Since an intractable disease is also untreatable, its diagnosis is not testable (or falsifiable) in Popper's sense. The framework provides also means to test the relevancy of cancer theories to human cancer.

Animals↗