Biomedical subjects

Hai-Shan Wu

Publications and source records attributed to Hai-Shan Wu.

7 recordsLinked to original sources

PubMed2006

A biased median filtering algorithm for segmentation of intestinal cell gland images.

In this paper, we introduce a biased median filtering image segmentation algorithm for intestinal cell glands consisting of goblet cells. While segmentation of individual cells are generally based on the dissimilarities in intensities, textures, and shapes between cell regions and background, the proposed segmentation algorithm of intestine cell glands is based on the differences in cell distributions. The intestine cell glands consist of goblet cells that are distributed in the chain-organized patterns in contrast to the more randomly distributed nongoblet cells scattered in the bright background. Four biased median filters with long rectangular windows of identical dimension, but different orientations, are designed based on the shapes and distributions of cells. Each biased median filter identifies a part of gland segments in a particular direction. The complete gland regions are the combined responses of the four biased median filters. A postprocessing procedure is designed to reduce the defects that may occur when glands are located very close together and to narrow the gapping areas because of the thin distribution of goblet cells. Segmentation results of real intestinal cell gland images are provided to show the effectiveness of the proposed algorithm.

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PubMed2006

Automatic image segmentation with linear clustering for quantification of neointimal formation after surgical vein grafting.

OBJECTIVE: To identify extracellular matrix deposition on combined Masson elastin stains from cross-sectional, fixed vein grafts. STUDY DESIGN: Source vectors from RGB components of color images are transformed into new vectors with most of the energy concentrated in fewer coefficients based on the eigenvalues and eigenvectors of their co-variance matrix so their dimension can be reduced for efficient computation and analysis. The vectors are distributed in a triangular shape in which most vectors are located in a long, narrow strip that can be approximated by a straight line while a separate group of vectors from collagen areas form a loose cluster away from the line. An iterative procedure has been developed for the representative vectors in the 2 centroids for linear and circular clusters. The linear centroid consists of all vectors in a straight line, and the centroid of the circular cluster is a single vector. Vector classification is based on the measure of its distance to each of the 2 centroids. RESULTS: The automatic segmentation of the collagen content pixels in green-blue matches the image background color. CONCLUSION: The procedure automatically quantifies and characterizes the neointimal deposition after surgical vein grafting in mice.

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PubMed2005

Segmentation of microscopic images of small intestinal glands with directional 2-D filters.

We present an image segmentation algorithm for small intestinal glands consisting of goblet cells that are evenly distributed and arranged in parallel at the base. Making use of the properties of the chain distribution of the goblet cells, directional 2-dimensional (2-D) linear filters with different orientations were designed to enhance the rims of the intestinal glands. Segmentations are based on the combined responses of the multiple zero-phase directional 2-D linear filters. For comparisons, outputs of combined directional filters are shown along with those of the comparable nondirectional Gaussian filters. Segmentation results of small intestinal glands of both normal and cancer cases are provided.

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PubMed2004

Characterization of ovarian nuclei with the parameter of power ratio.

The nucleoli and chromatin clumps of ovarian cells contain important features in discriminating malignant cells from normal ones. In geometric properties, the ovarian nucleoli and chromatin clumps appear as irregularly shaped dark spots in the nuclear images from specimens immunohistochemically stained with antibody to Mib-1. Malignant cells often have more active and larger nucleoli and chromatin clumps. However, estimating the size of the nucleoli or chromatin clumps is a difficult task since it is not easy to recognize and accurately separate the regions of nucleoli and chromatin clumps from the rest of the nuclei that are highly irregular and variant in contents and intensities. In this paper, we develop a method to derive a parameter called power ratio that is proportionally related to the size of nucleoli and chromatin clumps based on an ideal nuclear model without the region segmentation of nucleoli or chromatin clumps. Results of characterization of the parameter and comparison between malignant and normal cells are provided.

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PubMed2004

Relationship between sestamibi uptake, parathyroid hormone assay, and nuclear morphology in primary hyperparathyroidism.

BACKGROUND: Technetium-99m-sestamibi scanning and the intraoperative intact parathyroid hormone (iPTH) assay have permitted development of focused parathyroid techniques for treatment of primary hyperparathyroidism. The purpose of this study was to assess if any pre- and intraoperative factors (degree of sestamibi uptake and iPTH levels) were associated with postoperative results (resected gland weight and parathyroid nuclear morphology). STUDY DESIGN: We performed a retrospective analysis of 101 consecutive patients who underwent preoperative sestamibi scintigraphy and a targeted parathyroid exploration for primary hyperparathyroidism. Sestamibi uptake was graded visually on a 4-point scale of 0 (no uptake or false-negative result) to 3 (high uptake) and compared with respect to iPTH levels, gland morphology, and specimen weight. A Kruskal-Wallis test and a Pearson test were used for the statistical analysis. RESULTS: Degree of sestamibi uptake was associated with gland weight (median weight of 250 mg, 340 mg, 655 mg, 1,400 mg for grades 0, 1, 2, and 3, respectively, p < 0.001). The uptake of sestamibi was also associated with preoperative PTH levels (median PTH levels of 113, 151, 129, and 170 pg/mL for grades 0, 1, 2, and 3, respectively, p = 0.02), but not with the other parameters. The weight of resected gland(s) was associated with preoperative PTH levels (p = 0.02), and with some of the morphologic nuclear data (mean surface area (p = 0.02), maximum diameter (p = 0.01), and perimeter of the nuclei (p = 0.01). CONCLUSIONS: These data suggest that false-negative sestamibi scanning (visual score of 0) might result when hypersecreting parathyroid glands are small. Preoperative PTH level might be useful to estimate the amount of hypersecreting tissue to be resected.

Aged↗

PubMed2003

Applications of image analysis to anatomic pathology: realities and promises.

Image Analysis in Pathology is viewed as an ancillary method meant to provide objective support in the resolution of difficult problems. Its Achilles heel is the process of nuclear segmentation (delimitation of the nuclear membrane) which is extremely difficult in pathology materials. Although interactive segmentation procedures are available no reliable fully automatic method has been described. The only application of image analysis that has truly succeeded in Pathology is DNA ploidy measurement. A very desirable application is the quantitation of immunohistochemical markers, which is technically challenging, has been resolved only in certain cases and is unlikely to have a general solution. Nuclear quantitation has repeatedly proven to be helpful in reaching differential diagnoses, in particular when based on size distributions of nuclear profiles rather than its average, but is hampered by the segmentation problem discussed above. Texture analysis of chromatin is an exciting, mathematically complex application likely to succeed, for which many approaches have been described. Finally a diagnosis (classification) can be obtained based on algorithms applied to multiple descriptors of tumor cells (for instance nuclear sizes, chromatin texture, shape, etc). The best classificatory approaches are neural networks (a form of artificial intelligencee), multivariate analysis, and logistic regression (statistical).

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PubMed2002

Reproductive pathology and sperm physiology in acid sphingomyelinase-deficient mice.

Types A and B Niemann-Pick disease (NPD) are lysosomal storage disorders resulting from the deficient activity of acid sphingomyelinase (ASM). In this manuscript we report the pathobiology of male gonadal tissue and sperm in a knockout mouse model of NPD and demonstrate the importance of ASM for normal sperm maturation and function. Characteristic lipid-filled vacuoles were evident in light micrographs of testis' seminiferous tubules and epithelial cells lining the epididymis of -/- mice. Electron micrographs extended these findings and revealed storage vesicles within Sertoli cells of the seminiferous tubules. Mature spermatozoa from -/- mice showed marked ASM deficiency and elevated levels of sphingomyelin and cholesterol. Flow cytometric analysis revealed that affected spermatozoa had disrupted plasma and acrosome membranes, and mitochondrial membrane depolarization. They also did not undergo proper capacitation. Morphological abnormalities such as kinks and bends at the midpiece-principle piece junction were evident in spermatozoa from affected mice, with consequent deficits in motility. Notably, the mutant sperm regained normal morphology on incubation in mild detergent, demonstrating that the bending defects were a direct consequence of membrane lipid accumulation. A mechanism for these abnormalities is proposed that suggests lipid accumulation in the gonads results in regulatory volume decrease defects within the developing sperm, and that regulatory volume decrease defects, in turn, lead to the observed abnormalities in sperm morphology and function. These results provide in vivo evidence that ASM activity plays a critical role in sperm maturation and function, and a basis for similar studies in sexually mature, male NPD patients.

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