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G Kampf

Publications and source records attributed to G Kampf.

70 records · Page 4Linked to original sources
PubMed1994

Time-dependent inhibition by glyceryl trinitrate of platelet aggregation caused by U46619 (a thromboxane/endoperoxide receptor agonist).

Glyceryl trinitrate is a weak inhibitor of platelet aggregation in vitro. Its effect on platelet aggregation in response to U46619 (a thromboxane/endoperoxide receptor agonist) was studied turbidometrically in platelet-rich plasma from healthy volunteers. The object was to determine whether inhibition was influenced by a period of preincubation between preparation of platelet-rich plasma and addition of glyceryl trinitrate. Incubation was performed at 37 degrees C and 22 degrees C. Samples were removed at intervals and transferred to an aggregometer cuvette at 37 degrees C. Glyceryl trinitrate (100 microM) or an equal volume of distilled water was added 5 min before U46619 (2 microM), and aggregation recorded as change in light transmission. Inhibition by glyceryl trinitrate was markedly time and temperature dependent, with a progressive increase in inhibitory potency between 120 and 300 min preincubation at 37 degrees C but not at 22 degrees C. The explanation of this is unknown but the effect was not influenced by lipopolysaccharide or by cycloheximide, so it does not appear to be due to exposure to endotoxin or to enzyme induction in vitro.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1992

Simultaneous study of the biodistribution of radio-yttrium complexed with EDTMP and citrate ligands in tumour-bearing rats.

The influence of the ligands ethylenediaminetetramethylene phosphonic acid (EDTMP) and citrate (CIT) on the biodistribution of radio-yttrium in rats bearing a DS-carcinosarcoma was compared. 88Y-EDTMP and 87Y-CIT were i.v. injected into the same animals. Faster blood clearance and higher renal excretion were observed for the EDTMP-ligand. Of high practical interest is the reduced liver uptake of radio-yttrium (by one order of magnitude) with the EDTMP complex. Since bone and tumour accumulation is only weakly influenced, high tumour-to-liver ratios (up to 14) were observed. We propose to use EDTMP or similar complex ligands for liver blocking when radionuclides like 90Y, 169Yb, 225Ac or other group 3 elements are to be applied in endoradionuclide therapy technique.

Animals↗
PubMed1990

Steps towards cancer therapy with radionuclides--a review including radiation biophysical aspects.

Though great advantages will be connected with endoradiotherapy, a lot of problems has still to be overcome, the greatest of them being without doubt the problem of selectivity of the carrier compounds. Some few of them have proved to be able to accumulate in certain cancers by reason of their incorporation as metabolites, especially in melanomas. The other great hope are the monoclonal antibodies or their fragments, and in this field much endeavour has been spent in the last years. Especially the two-step method of loading the radioactive nuclide to the antibodies when their binding to the cancer cells is complete appears very promising. Some other, unspecific vehicles may also prove suitable for accumulation in certain tumor types. For the selection of the nuclides it has to be considered that radiation biophysical experiments demonstrated that the critical targets for radiation action are with high probability the DNA superstructure units, and that the distribution of ionizations within them is decisive for the inactivation of a cell. With sparsely ionizing radiation (e.g. beta-radiation) rather high doses are required for reaching an adequate concentration of ionizations in these DNA units. Densely ionizing radiation with an LET of about 150 keV/microns exhibits the maximum relative biological effectiveness (12-16 referred to X-radiation). Therefore emitters of alpha-particles the LET of which lies actually somewhat lower, near 100 keV/microns, seem to be very suitable for endoradiotherapy. Moreover the short ranges of these particles (about 60 microns in tissue) render an extensive sparing of the surrounding normal tissue possible. The second group of effective nuclides is that of Auger electron emitters. The low-energy proportion of Auger electrons leads to a high ionization density in small volumes. The very short ranges of these electrons (in the nanometer range), however, require an incorporation of the nuclide into the cell nucleus if an effective cell inactivation is to occur. 211At (alpha-emitter) and 125I (Auger electron emitter) already proved their high inactivating effectiveness in cell cultures and their curative action in animal experiments, and studies of binding 211At to monoclonal antibodies are encouraging. Some other approaches proposed for the transport of radionuclides into tumor cells or for generating them within tumor tissue are also aimed in essential at the release of densely ionizing alpha-particles or of Auger electrons.

Animals↗
PubMed1988

Technetium mixed-ligand complexes containing bidentate phosphines and monodentate thiol ligands. Preparation, in vitro data and detection of a certain heart affinity.

TcO-4 is reduced by a mixture of phosphine and thiol ligands to yield cationic complexes in which both ligands are coordinated. Polar and lipophilic properties of the products can easily be controlled by variation of either of the ligands. The yields are always high. Potential heart affinity of the compounds was screened by means of the isolated perfused rat heart. Some of the complexes show significant heart uptake and good retention in the myocardial tissue.

Animals↗
PubMed1987

Evaluation of potential heart affine compounds by use of the isolated perfused rat heart.

99mTc-organocation complexes were screened for heart affinity using the isolated perfused rat heart. The 99mTc-I compounds are better extracted by the heart and retained in it than the 99mTc-III compounds. 99mTcCl2(DMPE)2+ shows low uptake (15%) and fast washout, but no impairment of uptake after incubation with human serum albumin(HSA), with a modified preparation, initial uptake is not much better (18%) but washout is clearly diminished. 99mTc(DMPE)3+ is taken up to a greater extent (33%) if administered solely, but when given in conjunction with HSA, uptake decreases to about 4% because of strong affinity of the complex to the protein, but this compound persists well in the tissue. Detergents like tween 80 and dioctylsulphosuccinate are able to cause higher uptake of 99mTc(DMPE)3+ even in the presence of HSA, thus indicating a diminished binding of the compound to the protein. 99mTc(CN-t-butyl)6+ shows very high uptake (80%) by the heart, which is only moderately diminished by addition of HSA (to 38%), and persists excellently in the myocardium. Basic features of the compounds such as accumulation in and elimination from the myocardium as well as plasma protein binding and their mutual relationships are well reflected by the isolated heart model.

Animals↗
PubMedDate not supplied

[Double-stranded DNA breaks and inactivation of mammalian cells in relation to the LET of the radiation--comparison between experiment and theory].

In experiments on Chinese hamster cells the survival curves and the yield of double-strand DNA breaks were determined after irradiation at different LET. The comparison of the experimental results and the survival curves calculated on the basis of Günter-Schultz's theory of radiation inactivation of cells has demonstrated that radiation-induced double-strand DNA breaks are responsible for the lethal effect of radiation on cells.

Alpha Particles↗
PubMedDate not supplied

Nosocomial wound infections: a prevalence study and analysis of risk factors.

This first German prevalence study surveilling nosocomial wound infections (NWI) was carried out in 72 representatively selected hospitals. NWI were recorded by 4 validated investigators. Seventy-nine NWI were recorded among 4983 operated patients (prevalence rate: 1.61%), most of them after amputation of limbs (6.1%) and operations on the colon or rectum (3.1%). The 3 risk factors from the NNIS (National Nosocomial Infection Surveillance) index for postoperative wound infections were for the first time applied in this prevalence study. Patients with contaminated wounds had significantly more wound infections (P=0.01, likelihood ratio test) whereas, in contrast to the NNIS index, patients with ASA score >3 (P= 0.07) or long lasting operations (>75th percentile) did not (P=0.1). Therefore, for the stratification of NWI rates wound contamination is the single most important factor.

Cross Infection↗