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Biomedical subjects

R Panigel

Publications and source records attributed to R Panigel.

4 recordsLinked to original sources
PubMed1986

Liposomes containing paramagnetic macromolecules as MRI contrast agents.

The use of paramagnetic ions, bound to macromolecules and trapped in liposomes, as MRI contrast agents is suggested. As an example, the system of Mn2+ bound to serum proteins was tested. The binding of the metal ions to the macromolecules enhances their relaxation and at the same time decreases their rate of diffusion out of the liposomes. The use of liposomes is expected to reduce the potential toxicity of the paramagnetic ions and allows their targeting toward specific tissues.

Beta-Globulins↗
PubMed1977

The circular polarization of fluorescence of the ionophore lasalocid A(X-537A) and some of its metal complexes.

The conformation of the ionophore lasalocid A (X-537A) and its complexes with metal ions was probed by the circular polarization of their luminescence (CPL). The CPL of each complex in methanol was found to be different than when in n-hexane. Furthermore, the different metal ion complexes investigated had a different CPL spectrum in each solvent. These findings indicate wide variability in the conformation of the complexes depending on the metal ion and the solvent. From the spectral behaviour of the CPL it was concluded that at least some of the complexes exist in more than one form in solution. A comparison between the CPL and CD spectra indicates a change in the conformation of the ionophore in the vicinity of the salicylate chromophore upon electronic excitation.

Anti-Bacterial Agents↗
PubMed1975

Application of the carbonic anhydrase inhibitory effect of furosemide to the study of furosemide release from two of its diuretic derivatives.

Bovine carbonic anhydrase B (CA) inhibitory effect of furosemide was established in two pH values at 26 degress. FFBu [N-furfuryl-4-chloro-5-(butoxymethylsulfamoyl)anthranilic acid] and FFMe [N-furfuryl-4-chloro-5-(methoxy-methylsulfamoyl)anthranilic acid], two of its alkoxymethyl derivatives, did not exert any CA inhibitory effect at those conditions but were found to inhibit the CA activity after their hydrolysis, which yielded the furosemide molecule. The CA inhibitory effect of furosemide was utilized for determining the kinetic rate constants for the hydrolysis of FFBu and FFMe at various pH and temperature levels. The hydrolysis rate constants of FFBu and FFMe were pH-independent in the pH range tested, and the temperature dependence for FFBu yielded an activation energy of 18 kcal/mol. It is pointed out that the hydrolysis rates of FFBu may be important for the explanation of its possible delayed diuretic effect.

Carbonic Anhydrase Inhibitors↗