Preparation and characterization of low-molecular-weight heparin/protamine nanoparticles (LMW-H/P NPs) as FGF-2 carrier.

We produced low-molecular-weight heparin/protamine nanoparticles (LMW-H/P NPs) as a carrier for heparin-binding growth factors, such as fibroblast growth factor-2 (FGF-2). A mixture of low-molecular-weight heparin (MW: about 5000 Da, 6.4 mg/mL) and protamine (MW: about 3000 Da, 10 mg/mL) at a ratio of 7:3 (vol:vol) yields a dispersion of microparticles (1-6 microm in diameter). In this study, diluted low-molecular-weight heparin solution in saline (0.32 mg/mL) mixed with diluted protamine (0.5 mg/mL) at a ratio at 7:3 (vol:vol) resulted in soluble nanoparticles (112.5 +/- 46.1 nm in diameter). The generated NPs could be then stabilized by adding 2 mg/mL dextran (MW: 178-217 kDa) and remained soluble after lyophilization of dialyzed LMW-H/P NP solution. We then evaluated the capacity of LMW-H/P NPs to protect activity of FGF-2. Interaction between FGF-2 and LMW-H/P NPs substantially prolonged the biological half-life of FGF-2. Furthermore, FGF-2 molecules were protected from inactivation by heat and proteolysis in the presence of LMW-H/P NPs.

Convenient evaluation of mental stress with pupil diameter.

This study proposes a convenient method of evaluating mental stress. The potential of monitoring changes in pupil diameter as a measure of human reliability while operating human-machine systems was examined experimentally. An experiment was carried out to clarify the relation between changes in pupil diameter and autonomic nervous activity by measuring an electrocardiogram and pupil diameter when 10 subjects completed a time-sensitive task. The electrocardiogram was measured using a multitelemeter system and pupil diameter was measured using an eye-mark recorder. Several relationships between changes in pupil diameter and autonomic nervous activity were revealed and indicated that measurement of pupil diameter was an effective indicator of autonomic nervous activity. Therefore, it may be possible to develop a monitoring system that measures changes in pupil diameter as an indicator of the mental state of workers operating human-machine systems.

Effects of polyphenol on visual fatigue caused by VDT work.

Visual fatigue of VDT (visual display terminal) operators poses a serious problem for corporations where VDT work is a major part of operations. In this study, an investigation in a corporation was carried out to examine the effect of polyphenol on recovery from visual fatigue of the visual function caused by working at a VDT. Three kinds of parameters were used for evaluating the effect of polyphenol. As a subjective evaluation, the first was a questionnaire to ascertain subjective feelings of fatigue. As aspects of a physiological evaluation, the second and third parameters were the accommodative function and the flicker value.

Coatings of low-density lipoprotein and synthetic glycoconjugates as substrata for hepatocytes.

Asialoglycoprotein (ASGP) receptors expressed on rat hepatocytes interact with glycoproteins containing galactose or N-acetylgalactosamine residues at the nonreducing termini of oligosaccharide chains to mediate endocytosis, and cholesterol transport protein with apolipoprotein B (LDL, low-density lipoprotein) in plasma interacts with LDL receptors and heparinoids in the extracellular matrix. We developed novel techniques to prepare galactose- and LDL-immobilized culture plates, using galactose-tagged polystyrene (galactose-carrying polystyrene [GalCPS]: N-p-vinylbenzyl-O-beta-D-galactopyranosyl-[1-->4]-D-gluconamide) and poly(2-acrylamide-2-methyl-1-propanesulfonate) (PAPS), respectively. Hepatocytes adhered well to plates coated with either GalCPS or LDL, and therefore the GalCPS- and LDL-coated plates were examined as specific substrata for culturing hepatocytes. These cultures promoted the formation of three-dimensional, multicellular aggregates with regulation of excess proliferation of non-parenchymal cells. Furthermore, the LDL coating resulted in higher albumin synthesis and an identical level of lactate dehydrogenase (LDH) compared with cells cultured on collagen- and GalCPS-coated plates. Thus, the two culture systems described here, and especially the LDL-coated plates, have potential for the development of a hybrid artificial liver.

A novel autonomic activation measurement method for stress monitoring: non-contact measurement of heart rate variability using a compact microwave radar.

We developed a novel method for non-contact monitoring of stress-induced autonomic activation through the back of a chair, using a compact 24 GHz microwave radar (8 x 5 x 3 cm), without large-scale equipment and placing a heavy burden on the monitored individual. Following a silent period of 120 s, audio stimuli using a composite tone of 2,120 and 2,130 Hz sine-waves at 95 dB were conducted for 120 s. From dorsal, LF/HF of HRV reflecting sympatho-vagal balance was determined by microwave radar with the maximum entropy method using eight volunteers (mean age 23 +/- 1 years). Mean LF/HF measured by non-contact and contact (using electrocardiography for reference) methods during audio stimuli increased 34 and 37%, respectively, as compared with those of the silent period. Maximum cross-correlations between contact and non-contact measurements averaged 0.73 +/- 0.10. Our method appears to be promising for future monitoring of stress-induced autonomic activation of operators and may reduce stress-induced accidents.

Selection of hematopoietic stem cells with a combination of galactose-bound vinyl polymer and soybean agglutinin, a galactose-specific lectin.

BACKGROUND: Selection of hematopoietic stem cells can be used to prevent graft-versus-host disease (GVHD) after allograft transplantation. The purpose of the study was to examine a novel cell separation system comprising a galactose-bound vinyl polymer (Gal-VP) and soybean agglutinin (SBA), a galactose-specific lectin. STUDY DESIGN AND METHODS: A vinyl polymer (VP) containing alpha-1,6- and beta-1,4-linked galactose terminals was used to facilitate cell separation. A VP containing an alpha-1,4-linked glucose terminal (alpha-1,4-Glu-VP) was also synthesized as a control for alpha-1,6- and beta-1,4-Gal-VP. Peripheral blood samples were collected from healthy volunteers and umbilical cord blood cells were collected after normal labor. RESULTS: The sugar-VP was adsorbed on the surface of various materials. In the presence of SBA, T lymphocytes bound to beta-1,4-Gal-VP-coated microbeads, but not to alpha-1,4-Glu-VP-coated microbeads. When peripheral or cord blood cells were cultured on alpha-1,6-Gal-VP-coated plates, most red blood cells, lymphocytes, granulocytes, and monocytes adhered to the plate in the presence of 300 mg per mL SBA, whereas few CD34+ cells attached, even with 800 mg per mL SBA. CONCLUSION: SBA binds selectively to blood cells by recognizing cell-surface sugars, which are dependent on the extent of cellular differentiation. Therefore, the combination of alpha-1,6-Gal-VP and SBA might be useful for separation of blood cells according to their stage of differentiation and lineage.

Non-contact respiratory monitoring system using a ceiling-attached microwave antenna.

Using a microwave antenna attached to the room ceiling, we conducted non-contact monitoring of respiratory chest wall motions of subjects in bed and covered by a soft comfortable bedding, to measure the vital signs of patients under nursing care in a welfare institution. Long-term vital sign monitoring using electrodes places a heavy burden on monitored individuals. Our non-contact respiratory monitoring system comprises a 1,215 MHz-microwave radar (LDR-1), antenna box attached to the ceiling, and personal computer with analyzing software. The system was tested on eight healthy volunteers (mean age, 25 years; range, 21-44 years) and eight elderly volunteers with some disorders (mean age, 69 years; range, 66-75 years). Respiratory rates of subjects measured using this system correlated with rates measured using respiration sensors (r=0.97, P<0.001 for healthy volunteers, r=0.98, P<0.0001 for elderly volunteers). The system could monitor subtle changes in respiratory rate, and monitoring respiratory rate increases caused by disorders such as pneumonia will be possible.

Interaction study between synthetic glycoconjugate ligands and endocytic receptors using flow cytometry.

Flow cytometric analysis of synthetic galactosyl polymers, asialofetuin and LDL derivatives labeled with FITC (Fluorescein Isothiocyanate) was carried out to determine the phenotypes of endocytic receptors, such as asialoglycoprotein (ASPG) and the LDL receptor, on various types of cells. When FITC-labeled galactosyl polystyrene (GalCPS), being a synthetic ligand of ASPG, was applied to rat hepatocytes and human cancer cells (Hep G2 and Chang Liver), surface fluorescence intensities varied according to receptor expression on the cells. The fluorescence intensity originates from the calcium-dependent binding of the FITC-labeled GalCPS. Although unaltered by pre-treatment with glucosyl polystyrene (GluCPS), fetuin and LDL, the fluorescence intensity was suppressed by pre-treatment with (non-labeled) GalCPS and asialofetuin. Flow cytometry allowed us to demonstrate that the calcium-dependent binding of FITC-labeled LDL (prepared from rabbits) upon the addition of 17alpha-ethinyl estradiol enhances LDL receptor expression, and the expression is suppressed upon the addition of a monoclonal antibody to the LDL receptor. The binding efficiency based on the combination of FITC-labeled ligands suggests a possible application for the classification of cell types and conditions corresponding to endocytic receptor expression without the need for immuno-active antibodies or radiolabeled substances. Furthermore, the synthetic glycoconjugate (GalCPS) is shown to be a sensitive and useful marker for classification based on cell phenotype using flow cytometry.

Job Redesign Needs for Aged Workers.

The aim of this paper is to explore and present a proposal for redesigning elements of the workplace for agech workers. The method of research was to observe, record, and measure the actions of sitting workers performing assembly operations on electrical products in the Kani Plant Nagoya Works of Mitsubishi Electric Co. (Japan). The evaluation index used in the experiment was obtained by measuring time motion elements, cycle time per product, and motion velocity waves of elderly workers. Those motion characteristics were then compared to the motion characteristics of young workers. The results led to job redesign elements being identified to reduce handling factors of high difficulty for aged workers and to the necessity to consider a coefficient of correction in Method Time Measurement (MTM) according to differences in the manufactured object's weight.