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Biomedical subjects

B Holman

Publications and source records attributed to B Holman.

7 recordsLinked to original sources
PubMed2000

Modular robotic workcell for coagulation analysis.

BACKGROUND: Total laboratory automation (TLA) has been shown to increase laboratory efficiency and quality. However, modular automation is smaller, requires less initial capital, and requires less planning than TLA. We engineered and performed clinical trials on a modular robotic preanalytical workcell for coagulation analysis. METHODS: Timing studies were used to quantify the efficiency of the manual processes and to identify areas in the processing of coagulation specimens where bottlenecks and long waiting periods were encountered. We then designed our modular robotic system to eliminate these bottlenecks. Our robotic modular workcell was engineered to allow a choice of specimen introduction manually, by conveyor, or by mobile robot. Additional timing studies were performed during clinical trials of the robotic system. RESULTS: Prior to automation, the time required for preanalytical processing time was 18-107 min; after automation, it was 45-50 min. Additional improvements in workcell efficiency could be realized when high quality, prelabeled specimens were introduced into the system. CONCLUSION: Compared with manual methods, modular automation provides more predictable variation in specimen processing.

Blood Chemical Analysis↗
PubMed1998

Robotic automation of coagulation analysis.

Laboratory automation systems (LAS) have been installed in over 22 sites across North America providing automation of many preanalytical and analytical tasks in clinical laboratories. Only a few laboratories have automated the analysis of citrated whole blood for the diagnosis of hemostasis disorders. The analysis of coagulation factors in citrated blood requires a large amount of labor in order to provide rapid turnaround; thus automation of this analytical process is attractive. Therefore, we have created an automated coagulation workstation using a systematic approach to automation design and engineering. First, we used discrete event simulation to calculate potential throughput and to identify possible bottlenecks for the proposed coagulation workcell. We then created a three-dimensional animated computer model of the workstation to simplify workstation design. Finally, we constructed a prototype workcell using a mobile robot, an articulated robotic arm, and a coagulation analytical system.

Blood Coagulation Disorders↗
PubMed1990

Freeze-fracture electron microscopy of in vitro reconstructed human epidermis.

Epidermis has been reconstructed in vitro by seeding human keratinocytes on a human dermal substrate in an air-exposed culture. The end product has been examined by freeze-fracture electron microscopy, transmission electron microscopy (TEM) of thin sections, light microscopy, and lipid analysis using thin-layer chromatography. Light microscopic observation of hematoxylin-eosin stained, paraffin embedded cross-sections of the cell culture revealed a strong resemblance to its intact human counterpart, especially with respect to the morphologic organization in basal, spinous, granular, and horny layers. Freeze-fracture electron microscopy and TEM of thin sections generally confirmed the observed resemblances and additionally suggested the presence of lamellar bodies in the stratum granulosum, and of lamellar (lipid) structures between the corneocytes. However, some imperfections were also observed, including some anomalous lipid structures in the intercellular space. Lipid analyses in conjunction with essential fatty acid enrichment studies suggested that the structural anomalies observed in the cultured system may be caused by a lack of linoleyl-ceramides resulting from "immobilization" of linoleyl moieties in the form of triglycerides and phospholipids. In its present form, the air-exposed cell culture already looks very promising as a model for studies of, e.g., skin differentiation disorders such as psoriasis or ichthyosis, studies of the percutaneous penetration and intra(epi)dermal biotransformation of drugs, and skin toxicity screenings. It is furthermore expected that the aforementioned imperfections in the air-exposed cell culture should be avoidable by changing culture conditions such as the relative humidity and the pH, the composition of the medium, or both.

Cells, Cultured↗
PubMed1987

Phenotypic diversity of murine B16 melanoma detected by anti-B16 monoclonal antibodies.

A panel of monoclonal antibodies (MoAbs), produced against the murine B16 melanoma, has been used to characterize its phenotypic diversity. Six MoAbs that did not bind to primary cultures of kidney, brain or liver, spleen cells, thymocytes, 3T3 fibroblasts, melanin, or transferrin receptors were selected for further evaluation. Five MoAbs, which recognized surface antigens expressed on parental B16 cells and the B16-F1, B16-F10, B16-F10 FLR, and B16-BL6 sublines, did not appear to cross-react with each other, suggesting that they identified antigenically distinct epitopes. Four MoAbs, designated as IB16-2, IB16-4, IB16-8, and IB16-10, recognized B16 surface antigens that were variably expressed over short periods of time. This variable expression was independent of the cell cycle and was characteristic of four B16 sublines. Two of these MoAbs, both of the IgG2b isotype, fixed rabbit and guinea pig complement and were cytolytic in the presence of rabbit complement. One MoAb, designated IB16-6, recognized a surface antigen consistently expressed on greater than 90% of cells of both the parental tumor and the sublines. This MoAb bound to several murine and one human melanoma cell line, but not to other histopathological types of tumors or normal tissues. The cellular antigen that this antibody recognized was not detected in the cytoplasm, did not modulate in the presence of IB16-6, and was sensitive to trypsin, pronase, alcohols, acetone, and detergents, thereby suggesting that it was a protein. Our data are among the first that directly show the extent of phenotypic diversity of the B16 melanoma and sublines that have been derived from it.

Animals↗
PubMed1975

The nature of inhibition of cat brain mitochondrial monoamine oxidase by clorgyline.

In the cat brain the highest monoamine oxidase (MAO) activity is observed in the hypothalamus followed by hippocampus, caudate nucleus, pons and median cortex. Tyramine was the most actively deaminated substrate tested followed by dopamine. Clorgyline was more selective in its inhibitory action and could distinguish between tyramine and dopamine MAO deaminating system. The latter being more resistant to inhibition. The multiple forms of solubilized MAO as separated by polyacrylamide gel electrophoresis have varying phospholipid phosphorus content and sensitivity to inhibition by clorgyline in vitro and in vivo.

Animals↗