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- Chiu, D T, et al.
(författare)
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Chemical transformations in individual ultrasmall biomimetic containers
- 1999
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Ingår i: Science. - Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Univ Gothenburg, Dept Chem, S-41296 Gothenburg, Sweden. Pomona Coll, Dept Chem, Claremont, CA 91711 USA. : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 283:5409, s. 1892-1895
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Tidskriftsartikel (refereegranskat)abstract
- Individual phospholipid vesicles, 1 to 5 micrometers in diameter, containing a single reagent or a complete reaction system, were immobilized with an infrared laser optical trap or by adhesion to modified borosilicate glass surfaces. Chemical transformations were initiated either by electroporation or by electrofusion, in each case through application of a short (10-microsecond), intense (20 to 50 kilovolts per centimeter) electric pulse delivered across ultramicroelectrodes. Product formation was monitored by far-field laser fluorescence microscopy. The ultrasmall characteristic of this reaction volume led to rapid diffusional mixing that permits the study of fast chemical kinetics. This technique is also well suited for the study of reaction dynamics of biological molecules within lipid-enclosed nanoenvironments that mimic cell membranes.
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| 2. |
- Chiu, D T, et al.
(författare)
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Manipulating the biochemical nanoenvironment around single molecules contained within vesicles
- 1999
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Ingår i: Chemical Physics. - Univ Gothenburg, Dept Chem, SE-41296 Gothenburg, Sweden. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. : ELSEVIER. - 0301-0104 .- 1873-4421. ; 247:1, s. 133-139
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Tidskriftsartikel (refereegranskat)abstract
- A method to study single-molecule reactions confined in a biomimetic container is described. The technique combines rapid vesicle preparation, optical trapping and fluorescence confocal microscopy for performing simultaneous single-vesicle trapping and single-molecule detection experiments. The collisional environment between a single enzyme and substrate inside a vesicle is characterized by a Brownian dynamics Monte Carlo simulation. (C) 1999 Elsevier Science B.V. All rights reserved.
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| 3. |
- Grimvall, E, et al.
(författare)
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Monitoring of polychlorinated biphenyls in human blood plasma: methodological developments and influence of age, lactation, and fish consumption
- 1997
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Ingår i: Archives of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0090-4341 .- 1432-0703. ; 32:3, s. 329-336
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Tidskriftsartikel (refereegranskat)abstract
- Human plasma samples from 50 wives of fishermen have been analyzed with respect to PCBs. The non-ortho-substituted PCB congeners CB-126 and CB-169 were determined by mass spectrometry in negative ion chemical ionization mode, which demonstrated a limit of detection of 30 fg. The recoveries of the internal standards used for determination of ortho-substituted CBs were approximately 95%. Two methods, one gravimetric and the other based on enzymatic determinations of triglycerides, cholesterol and phospholipids, were compared for the determination of total amount of lipids in the plasma samples; the correlation coefficient was 0.82 and the slope 0.98. For practical reasons, enzymatic determinations are recommended for further use. The total, lipid-adjusted concentrations of PCBs in plasma were influenced by age, total lactation time and consumption of fatty fish from the Baltic Sea.
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| 4. |
- Humpel, C, et al.
(författare)
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Expression of nerve growth factor, brain-derived neurotrophic factor and neurotrophin-3 mRNAs in human cortical xenografts
- 1995
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Ingår i: Journal of neural transplantation & plasticity. - : Hindawi Limited. - 0792-8483. ; 5:4, s. 257-64
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Tidskriftsartikel (refereegranskat)abstract
- Trophic factors play an important role in the development of neurons and glia. In order to study the involvement of neurotrophins in human cortical development, human fetal parietal cortical tissue, obtained after early elective abortions, was transplanted to cortical cavities in immunosuppressed rats. Usingin situhybridization it was demonstrated that nerve growth factor, brain-derived neurotrophic factor and neurotrophin-3 mRNAs are expressed in developing human cortical xenografts. We conclude that neurotrophins may play a role in human cortical development and rat-derived astroglial cells could be involved in establishing reciprocal “permissive sites”.
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| 5. |
- Modig, C, et al.
(författare)
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MAP 0, a 400-kDa microtubule-associated protein unique to teleost fish.
- 1997
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Ingår i: Cell motility and the cytoskeleton. - 0886-1544. ; 38:3, s. 258-69
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Tidskriftsartikel (refereegranskat)abstract
- Microtubules from neural tissues of the Atlantic cod, Gadus morhua, and of several species of Antarctic teleosts are composed of tubulin and several microtubule-associated proteins (MAPs), one of which has an apparent molecular weight of approximately 400-430 kDa. Because its apparent molecular weight exceeds those of the MAP 1 proteins, we designate this high molecular weight teleost protein MAP 0. Cod MAP 0 failed to cross-react with antibodies specific for MAPs 1A, 1B and 2 of mammalian brain, for MAP H1 of squid optic lobe, and for chicken erythrocyte syncolin, which suggests that it has a novel structure. Similarly, MAP 0 from the Antarctic fish was not recognized by an antibody specific for bovine MAP 2. Together, these observations suggest that MAP 0 is a novel MAP that may be unique to fish. To determine the tissue specificity and phylogenetic distribution of this protein, we generated a rabbit polyclonal antibody against cod MAP 0. Using this antibody, we found that MAP 0 was present in microtubule proteins isolated from cod brain tissues and spinal cord but was absent in microtubules from heart, liver, and spleen. At the subcellular level, MAP 0 was distributed in cod brain cells in a punctate pattern coincident with microtubules but was absent in skin cells. MAP 0 was also detected in cells of the peripheral nervous system. A survey of microtubule proteins from chordates and invertebrates showed that anti-MAP 0-reactive homologs were present in five teleost species but not in more primitive fish and invertebrates or in higher vertebrates. MAP 0 bound to cod microtubules by ionic interaction at a site recognized competitively by bovine MAP 2. Although its function is unknown, MAP 0 does not share the microtubule-binding properties of the motor proteins kinesin and dynein. We propose that MAP 0 is a unique, teleost-specific MAP.
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| 6. |
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| 7. |
- Olmarker, K, et al.
(författare)
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Chondroitinase ABC (pharmaceutical grade) for chemonucleolysis. Functional and structural evaluation after local application on intraspinal nerve structures and blood vessels.
- 1996
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Ingår i: Spine. - : Ovid Technologies (Wolters Kluwer Health). - 0362-2436. ; 21:17, s. 1952-6
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Tidskriftsartikel (refereegranskat)abstract
- The effects on nerve tissue and blood vessels of locally applied chondroitinase ABC were studied in two experimental models using chymopapain and the vehicle of chondroitinase ABC for controls.To assess the effects of chondroitinase ABC on blood vessels and nerve tissue after local application.Chondroitinase ABC has been suggested for chemonucleolysis because it has a high specificity for nucleus pulposus matrix, which could mean a high efficiency in dissolving disc tissue combined with a low risk of side effects on other tissues.Chondroitinase ABC or controls were injected intrathecally in the pig, and nerve conduction velocity and histologic changes were assessed after 7 days. The same substances were injected into the hamster cheek pouch and studied for 60 minutes for microvascular effects. The vehicle for the enzyme was used as a negative control and chymopapain in a therapeutic concentration served as a positive control.In all series there was a slight intrathecal fibrotic reaction that was most pronounced after chymopapain injection. The effects on nerve conduction velocity and nerve morphology were similar between chondroitinase ABC and its vehicle. Chymopapain induced a significant reduction in nerve conduction velocity and pronounced histologic changes. In the cheek pouch, chymopapain induced a stand-still of blood flow at the injection site, and microhemorrhage and macromolecular leakage from the vessels at the border of the injection site. Only a slightly reduced blood flow was occasionally found after injection of chondroitinase ABC and controls.In agreement with the current literature, these observations indicate that chondroitinase ABC is safe regarding adverse effects on nerve tissue and blood vessels. The slight reduction in conduction velocity after intrathecal injection of chondroitinase ABC or its vehicle is most likely the result of surgical injury while releasing the nerve roots from the intrathecal fibrous adhesions. Such adhesions may be related to the laminectomy per se, and probably have no pathophysiologic significance.
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