Adherent-cell-dependent stimulation of CFU-GM by nucleobases, nucleosides, their analogues, and the hemoregulatory peptide dimer.

At suboptimal concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF), nucleobases and nucleosides as well as their analogues strongly stimulated aggregate (colony and cluster) formation from murine bone marrow granulocyte-macrophage colony-forming units (CFU-GM) in agar culture. Active compounds include 2'-deoxycytidine, thymidine, 5'-deoxyarabinosyl-cytosine, 5'-deoxy-5'-fluorothymidine, uracil, 6-methyluracil, orotic acid, and also purine derivatives as adenine, guanine, adenosine, and guanosine. The stimulation was almost identical to that obtained with the dimer of the hemoregulatory pentapeptide. In the absence of colony-stimulating factor (CSF) no stimulation was seen. After separation of adherent cells from the bone marrow cells, the stimulatory effect was lost. It also decreased when the number of bone marrow cells plated was diminished. This suggests that the tested compounds induce growth factor production in adherent cells. The structure/activity relationships indicate that the active compounds are nucleosides, or they may serve for nucleoside synthesis inside the cell. However, nucleotide formation is not necessary for activity.

Cisplatin induces the small heat shock protein hsp25 and thermotolerance in Ehrlich ascites tumor cells.

Exposure of Ehrlich ascites tumor (EAT) cells to the anticancer drug cisplatin results in an elevated abundance of three isoforms of the small heat shock protein hsp25 without inducing the general stress response as commonly observed after heat shock. The most effective cisplatin concentration (2.5 microM) is also most efficient in arresting cells in S phase suggesting a relationship between hsp25 expression and cell cycle events. Exposure to cisplatin results also in an increased thermotolerance of EAT cells.

Urinary retention in the course of neuroleptic therapy with haloperidol.

A case history was presented of a 49-year-old female patient, who had developed paranoid-hallucinatory schizophrenia for the first time and suffered from an acute functional bladder obstruction while receiving haloperidol. Thorough urological examination showed no pathologic findings except for a medium-grade urinary tract infection. No beneficial effects were obtained after application of parasympathicomimetic substances (carbachol, distigminebromide). After discontinuation of haloperidol therapy normal bladder function returned. The question as to the basic causative pharmacologic mechanism remains unanswered but the hypothesis that bladder dysfunction is due solely to the anticholinergic side-effects of haloperidol merits further critical elucidation and research.

The colony-to-cluster ratio in agar cultures of bone marrow. I. Constancy under standardized conditions and alteration in tumour-bearing mice and by various inhibitors added in vitro.

The growth of granulocyte-macrophage colony forming cells (GM-CFC) from mouse bone marrow was studied in agar cultures in glass capillaries. Under standard conditions with normal bone marrow a specific total number of cell clones (colonies + clusters) and also a specific colony-to-cluster ratio (CClR) was found for each of 4 different mouse strains. Both parameters were studied in tumour-bearing mice and found to be influenced independently and, in part, in an opposite way. Thus, for bone marrow of mice with the Ehrlich ascites carcinoma an inhibition of clone formation was found whereas the growth of those clones still formed was stimulated (only colonies present). "Natural" inhibitors as present in uraemic serum added to the cultures decreased the number of clones without altering the CClR. The same is true for the inhibitors in CSF-containing endotoxin serum. On the other hand, inhibitors such as spermine or the synthetic 3'-deoxy-3'-fluorothymidine depressed the clone formation as well as the growth rate of the clones (relative increase of clusters and decrease of colonies). It is concluded that the sensitivity of the GM-CFC against various influences may differ from that of the cells in the clones they form; therefore, the determination of the CClR will provide a more refined interpretation of influences on the haematopoietic system.

The colony-to-cluster ratio in agar cultures of bone marrow. II. Influence of a GM-CFC inhibiting factor.

An inhibitory activity for the proliferation of granulocyte-macrophage colony-forming cells (GM-CFC) of mouse bone marrow in soft-agar cultures was partly purified from rat bone marrow conditioned medium by ultrafiltration and gel chromatography. It was selective in that it also inhibited the proliferation of myeloid but not that of lymphatic mouse leukaemia cells. Even at strong (greater than 60%) inhibition of the formation of cell clones (colonies + clusters) the colony-to-cluster ratio (CClR) remained as in the controls. The data point to a long-lasting and selective effect of the inhibitor on the GM-CFC without influence on the proliferation of its progeny. This conclusion is confirmed by the temporal development of the inhibitory effect in the course of culture. The determination of the CClR enables one to discriminate between proliferation modulating effects (CClR alteration) and those acting via ON/OFF-switching mechanisms (CClR constancy) influencing the clone forming efficiency at all.

Aspects of chalone action.

The following aspects of action of a chalone-like factor for the Ehrlich ascites mammary carcinoma and of the granulocytic chalone are discussed: 1) Dependence on the state of proliferation. Rapidly growing cells respond poorly or not at all. 2) Antagonism with growth factors. The factor for the Ehrlich ascites mammary carcinoma is antagonized by physiological concentrations of insulin or by proinsulin. The granulocytic chalone is antagonized by colony stimulating factor. 3) Influence on cell cycle progression. Attempts and problems to analyse this influence for the factor for the Ehrlich ascites mammary carcinoma by flow cytometry are described.

[Granulocyte chalone: tissue specificity of action in short-term cultures]. / Granulozytenchalon: Gewebespezifität der Wirkung in Kurzzeitkulturen.

Granulocytic chalone containing extracts were obtained by incubating rat bone marrow cells in Hanks salt solution and further purification of the conditioned medium by ultrafiltration and gel chromatography. These extracts cause specific inhibition of 3H-thymidine incorporation in short-term cultures of rat bone marrow and murine myeloic leukemias. Ehrlich ascites tumour, spleen (mouse), lymphatic leukemia L1210 and melanoma AMel 3 (hamster) are not influenced under identical experimental conditions. Comparing the action of cell proliferation inhibitors (chalones) from Ehrlich ascites tumour and spleen lymphocytes it was shown that inhibition of 3H-thymidine incorporation occurs only with those cells corresponding to the origin of the inhibitor. Therefore, the described short-term cultures seem to be suitable for testing the tissue specificity of action, as the main criterion for authenticity of the chalone effect, at least in the case of granulocytic chalone.