A promising technique for transplantation of bone marrow-derived endothelial progenitor cells into rat heart.

OBJECTIVE: To investigate the feasibility of intracoronary application of endothelial progenitor cells and the subsequent distribution within the heart. METHODS: Endothelial progenitors cells (EPCs) cultured from rat bone marrow were identified by double-positive staining with Dil-Ac-LDL and BS1-lectin. Twenty-four hours before cell transplantation, EPCs were labeled with 5-bromo-2'-deoxyuridine (BrdU). Cells (5 x 10(5) in 250-microl medium) were injected into healthy rats, either as intracoronary application (n=11) or as intramyocardial injection (n = 6). At 15 min or 3 days posttransplantation, hearts as well as other organs (lung, liver, kidney, and spleen) were collected and processed for subsequent BrdU immunohistochemistry. The number of BrdU-positive cells per tissue area was counted. RESULTS: Compared to intramyocardial injection, intracoronary administration resulted in more than twice as much positive cells in the heart (P < .05), with no local differences within the heart. Whereas after 15 min, EPCs were equally distributed in all examined organs (except for the spleen), cells that were still present after 3 days, approximately 10%, were selectively restricted to the heart. CONCLUSIONS: Our data indicate that the intracoronary application provides a promising technique for EPC transplantation in the rat heart.     

Activation of a Ca2+-dependent K+ current by the oncogenic receptor protein tyrosine kinase v-Fms in mouse fibroblasts

We investigated the effects of the receptor-coupled protein tyrosine kinase (RTK) v-Fms on the membrane current properties of NIH3T3 mouse fibroblasts. We found that v-Fms, the oncogenic variant of the macrophage colony-stimulating factor receptor c-Fms, activates a K⁺ current that is absent in control cells. The activation of the K⁺ current was Ca²⁺-dependent, voltage-independent, and was completely blocked by the K⁺ channel blockers charybdotoxin, margatoxin and iberiotoxin with IC₅₀ values of 3nM, 18 nM and 76nM, respectively. To identify signalling components that mediate the activation of this K⁺ current, NIH3T3 cells that express different mutants of the wildtype v-Fms receptor were examined. Mutation of the binding site for the Ras-GTPase-activating protein led to a complete abolishment of the K⁺ current. A reduction of 76% and 63%, respectively, was observed upon mutation of either of the two binding sites for the growth factor receptor binding protein 2. Mutation of the ATP binding lobe, which disrupts the protein tyrosine kinase activity of v-Fms, led to a 55% reduction of the K⁺ current. Treatment of wild-type v-Fms cells with Clostridium sordellii lethal toxin or a farnesyl protein transferase inhibitor, both known to inhibit the biological function of Ras, reduced the K⁺ current amplitude to 17% and 6% of the control value, respectively. This is the first report showing that an oncogenic RTK can modulate K⁺ channel activity. Our results indicate that this effect is dependent on the binding of certain Ras-regulating proteins to the v-Fms receptor and is not abolished by disruption of its intrinsic protein tyrosine kinase activity. Furthermore, our data suggest that Ras plays a key role for K⁺ channel activation by the oncogenic RTK v-Fms. Received: 19 November 1997 / Accepted: 21 January 1998     

Bericht über das Internationale Symposium «Nerve Fibres and Inflammation», Erlangen, 13.–16. März 1988

Ohne Zusammenfassung     

Isolation of Flavonol Glycosides from Ginkgo biloba Leaves

6-Hydroxykynurenic acid and nine flavonol glycosides were isolated and identified from the leaves of GINKGO BILOBA: three of them were identified in Ginkgo for the first time, and two others are unusual P-coumaroyl esters.     

The thyroid axis and desipramine treatment in depression

Although there has been much recent investigation of the role of thyroid function in affective illness, few studies have addressed the effects of the tricyclic antidepressants on the pituitary-thyroid axis. In the present study, thyroid functions (TFTs) and thyrotropin-releasing hormone (TRH) stimulation of thyroid-stimulating hormone (TSH) were measured before and after treatment with desipramine (DMI) in 13 men with a diagnosis of major depressive disorder. All subjects had normal TFTs and baseline TSH measured in a drug-free state at the initiation of the study. Both mean free thyroxine index and baseline TSH decreased after DMI treatment. The amount of decrease in baseline TSH correlated with increase in delta TSH. Four subjects had blunted delta TSH (delta TSH less than or equal to 5 microIU/ml); three of these subjects "normalized" with treatment (delta TSH less than or equal to 5 microIU/ml; greater than or equal to 20 microIU/ml). Two subjects had a high delta TSH, and both "normalized" during treatment. The decrease in both free T4 index and TSH suggests a down-regulation of the thyroid axis at the hypothalamic level. "Normalization" of subtle dysregulation of the thyroid axis is suggested as a mechanism of antidepressant therapy in the treatment of some depressions.     

Radiologic search for embolized leaflets of prosthetic heart valves: A report of two cases

In a radiologic search for embolized leaflets of Edwards-Duromedics bileaflet valves in 2 patients, the embolized fragments were localized in the iliac vessels using computed tomography. Sonography was successful in one case and standard X-ray films of the abdomen were negative in both cases.In vitro investigations with Björk-Shiley and Edwards-Duromedics leaflets suggested that standard X-ray films of the abdomen and pelvis should be considered as the first investigational technique. If negative, computed tomography of the lower abdomen should be done.     

Radioreceptor Assay of Metoprolol in Human Plasma: Comparison with an Enantiospecific High-Performance Liquid Chromatographic (HPLC) Procedure

Plasma concentrations of metoprolol after acute and repetitive administration of R/S-metoprolol to healthy volunteers were measured by a -adrenoceptor subtype-specific radioreceptor assay (RRA) and by an enantiospecific high-performance liquid chromatographic (HPLC) method. In the RRA, R/S-metoprolol showed a 20-fold ₁-subtype selectivity: the S-( – )-enantiomer was 35-fold more potent than the R-( + )-enantiomer. A comparison between S-( – )-metoprolol concentrations detected in the plasma samples by HPLC and those detected by RRA yielded a 1/1 relationship, indicating that active metabolites are not present to a significant extent. These results were independent of the widely scattering metabolic clearance of metoprolol (with the potential of differences in the rate and extent of formation of active metabolites) in the volunteers. In general, HPLC methods can be validated by comparison with RRA in order to clarify whether active metabolites are present and—on the basis of the K_i value from RRA—whether the detection limit of the physicochemical procedure is sufficient to cover the therapeutically relevant range.