Search PubMed⌕ Search

Biomedical subjects

R Kaufmann

Publications and source records attributed to R Kaufmann.

At least 289 records · Page 16Linked to original sources
PubMed1981

Cell electrophoresis for diagnostic purposes. II. Critical evaluation of conventional cytopherometry.

Determination of the electrophoretic mobility of test cells has been widely used in an attempt to detect so-called lymphokines in a laboratory test for cancer, but operational difficulties are inherent in conventional cytopherometers. This study therefore investigates the technical and operational aspects of cell electrophoresis, using the Zeiss cytopherometer; e.g. influence of electro-osmosis, focus uncertainty, movement due to convection and other sources of error. Implications and possible improvements in the test are discussed.

Cell Movement↗
PubMed1980

Extraction and translation of collagen mRNA from fetal calf skin.

RNA was extracted from fetal calf skin by two different procedures, using phenol or guanidine hydrochloride. Poly(A)-rich RNA was separated by oligo(dT)-cellulose affinity chromatography and was further fractionated by sucrose density gradient centrifugation. When translated in an optimized wheat germ extract cell-free system, unfractionated guanidine-hydrochloride-extracted poly(A)-rich RNA directed the synthesis of two collagenase-sensitive protein bands, while phenol-extracted poly(A)-rich RNA with a sedimentation coefficient higher than 25 S was the only fraction to direct the same synthesis. On the basis of their electrophoretic mobility on a sodium dodecylsulfate/urea/polyacrylamide gel, these proteins were identified with procollagen alpha 1(I) and procollagen alpha 2. Inhibition of translation by phenol-extracted poly(A)-rich RNA with a sedimentation coefficient lower than 25 S was also observed. Guanidine-hydrochloride-extracted poly(A)-rich RNA from fetal skin directed the synthesis of three distinct collagenase-sensitive proteins in the micrococcal-nuclease-digested rabbit reticulocyte cell-free system; these seemed to correspond to procollagen alpha 1(I), procollagen alpha 2 and procollagen alpha 1 (III).

Animals↗
PubMed1980

Recent LAMMA studies of physiological cation distributions in retina tissues.

In shock frozen and freeze dried specimens of cat and frog retina distribution patterns of physiological cations were obtained by means of laser microprobe mass analysis with special emphasis to Ca and Ba in structural elements such as photoreceptors and melanin granules. Ca was found to be distributed along single cones of frog in a characteristic bimodal fashion whereas Na and K showed a rather homogeneous concentration profil. The presence of large amounts of Ba in pigment granula was reconfirmed in retina pigment epithelium and, newly, in melanoma cells. Additional microchemical characterization concerned organic constituents of various tissue layers of the retina.

Animals↗
PubMed1979

The laser microprobe mass analyzer (LAMMA): a new instrument for biomedical microprobe analysis.

After a short review of the general state of the art of microprobe analysis, recent achievements of a new system, the laser microprobe mass analyzer (LAMMA) are presented. The LAMMA-instrument, which was primarily developed for biomedical purposes, has recently been used on a large variety of specimen, biological, technical, organic and inorganic in nature. Detection limits, mass resolution and reproducibility were improved such that for many elements measurements could be extended down to the subppm range. For bulk analysis, a separate version of the LAMMA-instrument is under development. The examples of LAMMA-applications given in this paper include muscle tissue (physiological cations), uterine tissue (Fe), retina tissues (Na, Mgmg, K, Ca and Ba!), airborne particles (Pb, Fe, Al, Ti, Mn, Ca, Zn), cerebral tissue (Li), and pure cristalline organic materials.

Animals↗
PubMed1979

[The resistance of a maternally-derived immunity of baby mice against mousepox--experiments regarding a special possibility of immunization with orthopox viruses (author's transl)].

In the scope of research concerning new proplylactic possibilities against mousepox we tested the resistance of a passive immunity of baby mice whose mothers had been immunized before or during pregnancy several times with either the vaccinia virus strains MVA, CVB or the so-called attenuated ectromelia virus strain "Hampstead" respectively. The vaccines CVB and "Hampstead" were found to cause the production of haemagglutination-inhibiting antibodies only. A passively-transmitted immunity of baby mice was proven to be effective against an intraperitoneal challenge-infection with a virulent ectromelia virus strain for as long a period as 3 weeks after birth, if their mothers had been vaccinated with either of the following: 10(2,0) and 10(4,0) KID50 of the "Hampstead" strain, or one of the vaccinia virus strains in a dosage 100-times as large. The vaccination did not lead to an intrauterine infection of the fetuses. After 224 tissue culture passages in mouse fibroblast cells (line 3T6), THE "Hampstead" strain was found te be still virulent for baby mice; however, female adult mice which had been intraperitoneally inoculated with 10(2,0) and then 10(4,0) KID50 two weeks later demonstrated no signs of mousepox. The possibility for using this ectromelia virus strain instead of vaccinia virus for active immunization against mousepox of young animals under the protection of a homologous passive immunity is discussed.

Animals↗
PubMed1979

Laser microprobe mass analysis: achievements and aspects.

After a short review of the general state of the art of laser microprobe analysis, recent achievements of the laser microprobe mass analyzer (LAMMA) are presented. The Lamma-instrument, which was primarily developed for biomedical purposes has been recently used on a large variety of specimens: biological, technical, organic and inorganic in nature. Detection limits, mass resolution and reproducibility have been improved so that for many elements measurements can be extended down to the subppm range. For bulk analysis a separate version of the LAMMA-instrument has been developed. The examples of LAMMA-applications given in this paper include muscle tissue (physiological cations), uterine tissue (Fe), retina tissues (Na, Mg, K, Ca and Ba), airborne particles (Pb, Fe, Al, Ti, Mn, Ca, Zn), cerebral tissue (Li), a fluorinated drug, pure crystalline organic materials (including nicotinic acid) and a selection of non biological materials (for instance thin films).

Aerosols↗
PubMed1978

Investigations on the structure-activity relationships of verapamil.

An investigation was carried out towards a qualitative and quantitative structure-activity relationship of verapamil based on an analysis of the frequency-dependent negative inotropic action exerted in cat papillary muscles by various groups of verapamil derivatives. (1) Substituents of the benzene ring near the asymmetric carbon atom and the isopropyl group were found to be no essential substituents for the frequency-dependent negative inotropic action of verapamil but to have a strong influence on the potency of the drug. (2) Both the tertiary amino nitrogen and the two benzene rings are essential for the frequency-dependent negative inotropic action of verapamil (3) The molecular importance of the N-methyl group is probably based on steric effects. (4) Investigations of the verapamil derivative H 1 revealed that a quaternization of the drug is followed by a total loss of effectiveness. (5) No significant correlation of the biological activity of verapamil derivatives with the partition coefficient P has been obtained. (6) Hansch analysis with verapamil derivatives of group A (= different substitution of the benzene ring near C) shows that the variance of biological activity can be optimally correlated to a combination of the Hammett constant and the molar volume. Hansch analysis of group B (= exchange of isopropyl group) led to the conclusion that hydrophobic effects are responsible for the influence of the isopropyl substituent.

Animals↗