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At least 19 recordsLinked to original sources
PubMed1978

A magnet tip for controlled removal of magnetic foreign bodies.

I designed a small diameter magnet tip for intraocular removal of foreign bodies, particularly at the time of vitrectomy. Advantages of the intraocular tip include: (1) reduced likelihood of scraping of the foreign body along the retinal surface while in the magnetic field; (2) reduced chance of incarcerating the retina or choroid, or both, between the magnet and the foreign body during removal. Although the intraocular tip is less strong than conventional shorter tips, it provides greater control in the removal of intraocular foreign bodies when sufficient magnet strength is present.

Eye Foreign Bodies↗
PubMed1979

Nuclear magnetic resonance multiwindow analysis of proton local fields and magnetization distribution in natural and deuterated mouse muscle.

The proton free-induction decays, spin-spin relaxation times, local fields in the rotating frame, and spin-lattice relaxation times in the laboratory and rotating frames, in natural and fully deuterated mouse muscle, are reported. Measurements were taken above and below freezing temperature and at two time windows on the free-induction decay. A comparative analysis show that the magnetization fractions deduced from the different experiments are in good agreement. The main conclusion is that the resolution of the (heterogeneous) muscle nuclear magnetic resonance (NMR) response is improved by the multiwindow analysis.

Animals↗
PubMed1977

The trajectories of particles suspended in electrolytes under the influence of crossed electric and magnetic fields. Possible explanation of the sensitivity of organism to magnetic fields.

We observed that particles, suspended in an electrolyte and brought into crossed magnetic and electric fields of low intensities, will deviate in the central part of the electrophoresis chamber of a standard Zeiss Cytopherometer with a component vertical to both fields. The direction and magnitude, however, were sharply at variance with what would be expected by the action of the Lorentz force (EMF) on the surface of the particles. The magnitude of the deviation depends upon the magnetic and electric field strength, the ion concentration of the suspension medium and the geometry of the chamber. The movement of the particles is due to streaming of the electrolyte which is mainly caused by inhomogeneities of the electric field in the electrophoresis chamber. The magnitude of the effect is high enough to occur physiological conditions. Magneto-electrophoretic streaming might eventually act as a transducer mechanism which could explain the ability of some animals to orientate themselves in the geomagnetic field.

Electricity↗
PubMed1977

Mössbauer investigation of deoxymyoglobin in a high magnetic field. Orientation of the electric field gradient and magnetic tensors.

We have examined the Mössbauer spectra of deosymyoglobin in a 6 T magnetic field in the temperature range 4.2-195 K. Spectra were fitted by the least-squares method using a phenomenological model in which the internal magnetic hyperfine field was assumed to be related to the applied field by a temperature dependent tensor õmega. The results indicate that õmega has axial symmetry and a principal axis system aligned with that of the electric field gradient (efg). The principal component of the latter is negative and lies on the symmetry axis of õmega. Our fits indicate that of efg asymmetry parameter is eta = 0.7, with no appreciable temperature dependence. Both axial and transverse components of õmega have the expected 1/T temperature dependence for T greater than 20 K. Our experimentally determined value of eta, combined with published single crystal zero-field measurements, constrains the efg-heme relative orientation to two possibilities. In neither of these is an efg principal axis near to the heme normal.

Animals↗
PubMed1979

Polyglutaraldehyde: a new reagent for coupling proteins to microspheres and for labeling cell-surface receptions. II. Simplified labeling method by means of non-magnetic and magnetic polyglutaraldehyde microspheres.

Procedures were developed for the synthesis of a new immunoreagent in form of polyglutaraldehyde (PGL) microspheres in sizes ranging from about 50 nm to 1.5 micron. Addition of fluorochromes during synthesis yielded microspheres of high fluorescence intensity. By carrying out the polymerization of glutaraldehyde in presence of iron oxide, magnetic PGL microspheres were produced. Antibody conjugates obtained by interaction of PGL microspheres with immunoglobulins were used to label human red blood cells (RBC) and lymphocytes. A simple method for the separation of magnetically labeled human RBC from unlabeled cells was demonstrated.

Aldehydes↗
PubMed1979

Lithium-7 nuclear magnetic resonance, water proton nuclear magnetic resonance, and gadolinium electron paramagnetic resonance studies of the sarcoplasmic reticulum calcium ion transport adenosine triphosphatase.

The interactions of gadolinium ion, lithium, and two substrate analogues, beta,gamma-imido-ATP (AMP-PNP) and tridentate CrATP, with the calcium ion transport adenosine triphosphatase (Ca2+-ATPase) of rabbit muscle sarcoplasmic reticulum have been examined by using 7Li+ NMR, water proton NMR, and Gd3+ EPR studies. Steady-state phosphorylation studies indicate that Gd3+ binds to the Ca2+ activator sites on the enzyme with an affinity which is approximately 10 times greater than that of Ca2+. 7Li+, which activates the Ca2+-ATPase in place of K+, has been found to be a suitable nucleus for probing the active sites of monovalent cation-requiring enzymes. 7Li+ nuclear relaxation studies demonstrate that the binding of Gd3+ ion to the two Ca2+ sites on Ca2+-ATPase increases the longitudinal relaxation rate (1/T1) of enzyme-bound Li+. The increase in 1/T1 was not observed in the absence of enzyme, indicating that the ATPase enhances the parmagnetic effect of Gd3+ on 1/T1 of 7Li+. Water proton relaxation studies also show that the ATPase binds Gd3+ at two tight-binding sites. Titrations of Gd3+ solutions with Ca2+-ATPase indicate that the tighter of the two Gd3+-binding sites (site 1) provides a ghigher enhancement of water relaxation than the other, weaker Gd3+ site (site 2) and also indicate that the average of the enhancements at the two sites is 7.4. These data, together with a titration of the ATPase with Gd3+ ion, yield enhancements, epsilonB, of 9.4 at site 1 and 5.4 at site 2. Analysis of the frequency dependence of 1/T1 of water indicates that the electron spin relaxation taus of Gd3+ is unusually long (2 X 10(-9) s) and suggests that the Ca2+-binding sites on the ATPase experience a reduced accessiblity of solvent water. This may indicate that the Ca2+ sites on the Ca2+-ATPase are buried or occluded within a cleft or channel in the enzyme. The analysis of the frequency dependence is also consistent with three exchangeable water protons on Gd3+ at site 1 and two fast exchanging water protons at site 2. Addition of the nonhydrolyzing substrate analogues, AMP-PNP and tridenate CrATP, to the enzyme-Gd3+ complex results in a decrease in the observed enhancement, with little change in the dipolar correlation time for Gd3+, consistent with a substrate-induced decrease in the number of fast-exchanging water protons on enzyme-bound Gd3+. From the effect of Gd3+ on 1/T1 of enzyme-bound Li+, Gd3+-Li+ separations of 7.0 and 9.1 A are calculated. On the assumption of a single Li+ site on the enzyme, these distances set an upper limit on the separation between Ca2+ sites on the enzyme of 16.1 A.

Animals↗