The effect of alpha-melanocyte stimulating hormone on endotoxin-induced intestinal injury.

We investigated the effect of alpha-melanocyte stimulating hormone (alpha-MSH) on endotoxin-induced intestinal inflammation and the role of nitric oxide and prostaglandins in this response. alpha-MSH treatment (25 microg/rat, intraperitoneally (i.p.); twice daily) reduced the severity of the lesions macroscopically and microscopically. This protective effect was found to be confined mainly to the distal ileum. These lesions were reversed by pretreatment with the non-selective COX inhibitor indomethacin (10 mg/kg, subcutaneously (s.c.)) but not by the selective COX-2 inhibitor nimesulide (3 mg/kg, s.c.), the NO donor sodium nitroprusside (4 mg/kg, i.v.) or the iNOS inhibitor dexamethasone (3 mg./kg, i.p.) at macroscopic level and reversed by Indo or Dex at microscopic level. Increased peroxidase activity -index of tissue neutrophil infiltration- in the distal ileum of LPS-treated rats was decreased by alpha-MSH and this effect was reversed by pretreatment with Indo. In conclusion, the neuropeptide alpha-MSH has a beneficial effect on endotoxin-induced distal intestinal lesions by a mechanism which probably involves nitric oxide and COX-1 derived prostaglandins.     

Mitogenic effect on human lymphocytes of insolubilized anti-immunoglobulins. I. Specificity of the stimulating agent

The mitogenic response of peripheral blood lymphocytes to various anti-immunoglobulin reagents has been studied by measuring incorporation of a radioactive thymidine into macromolecules. Coupling of anti-F(ab')2 or anti-light chain antibodies to Sepharose beads leads to a 5-fold increase in their mitogenic capacity with 50-fold less antibodies per culture. Pepsin-digested F(ab')2 fragments had a mitogenic capacity similar to intact antibody molecules. Anti-F(ab')2 antibodies purified by immunoabsorbent columns were found to be more effective as mitogen than unpurified antibody fractions. Antibodies to kappa- or lambda-light chains were found to be mitogenic, whereas antibodies specific to various heavy chain classes failed to induce a significant response. Isolated light chains were much more effective in inhibiting the reaction than isolated mu-chains. It is concluded that insolubilized anti-light chain antibodies are mitogenic to human peripheral blood lymphocytes.     

Chronic haloperidol: tolerance to the stimulating effect on striatal tyrosine hydroxylase.

Chronic treatment with haloperidol (1 mg/kg twice daily for 45 days) causes tolerance to the stimulating effect of the drug on striatal tyrosine hydroxylase activity. Tolerance is present even up to 7 days after interruption of treatment and is extended to fluphenazine.     

The stimulating effect of a cold, dark pretreatment on the etioplast/chloroplast transformation of angiosperms. I. The stimulating effect of cold predarkening on different stages of greening under white light

Schönbohm, E., Stute, U., Thienhaus, P. and Werner, U. 1988. The stimulating effect of a cold, dark pretreatment on the etioplast/chloroplast transformation of angiosperms I. The stimulating effect of cold predarkening on different stages of greening under white light. - Physiol. Plant. 72: 541–546.
The etioplast/chloroplast transformation in angiosperms is controlled by light; most of the processes are mediated by phytochrome. We have shown that in the primary leaves of etiolated seedlings of wheat ( Triticum aestivum L. cv. Kolibri), fire-bean ( Phaseolus multiflorus L. cv. Preisgewinner) and in the cotyledons of etiolated sun flower seedlings ( Helianthus annuus L. cv. macrocarpa) the chlorophyll accumulation in the phase after the end of the lag phase can be greatly stimulated by a cold predarkening period. This effect is not necessarily coupled with a red preirradiation. Furthermore the lag phase can be dramatically shortened by the cold, dark pretreatment, whereas the amount of photoconvertible protochlorophyll(ide) in the darkness remains unaffected by the cold, dark pretreatment. The stimulating effect of a cold, predarkening period on greening is fully reversible by a warm, dark phase that is placed between the cold period and the onset of the continuous white light phase. These findings cannot be generalized: We could demonstrate that in the tropical plant Momordica charantia greening under white light was not affected by different temperature pretreatments during predarkening. The stimulating effect of a cold, predarkening period on greening is assumed to have ecological relevance.     

Study of the stimulating effect of the sympathetic stem on the stomach contraction

Stimulation of the sympathetic stem chest portion induces enhancement rather than suppression of gastric contractions. The activating effect is more obvious under conditions of the alpha- and beta-adrenoreceptors blockade with phenolamine and obsidan, and eliminated with the smooth muscle serotoninoreceptors blocking agent lisergol. The findings suggest that the sympathetic stem includes some serotoninergic neural fibres exerting a strong effect upon gastric and intestinal contractions. A previously unknown serotoninergic part of the vegetative nervous system controlling the internal organs functions, seems to exist in the organism.     

The effect of endotoxin on the colony stimulating activity (CSA) in sera of mice.

We found one peak of a new molecular form of CSA after chromatography on Sephadex G-200 in the serum of mice treated with endotoxin. Total activity and two peaks of CSA were much higher than controls.     

The stimulating effect of N-nitroso-ethylurea on the biosynthetic ability of Aspergillus oryzae

The mutagenic action of N-nitroso-N-ethylurea (NEU) taken at shock and prolonged doses together on Aspergillus oryzae yielded 98% of populations with an elevated synthesis of proteolytic enzymes. The combined action of shock and prolonged NEU doses had an advantage over a shock pulse dose because the frequency of mutations rose 2-16 times and the populations accumulated proteolytic enzymes within the range of 9 to 24 activity units. As was shown using a certain number of populations selected at random, the elevated accumulation of proteolytic enzymes in the medium remained stable within eight generations.     

The effect of colony stimulating factor-1 in vivo

The present studies were undertaken to determine whether colony stimulating factor-1 (CSF-1) stimulates hemopoietic cell proliferation and differentiation in vivo. Groups of mice were injected with 25,000 units of pure, endotoxin-free L-cell CSF every 6 hours for intervals up to 8 days. Virtually no changes were detected in blood neutrophils or monocytes. No consistent increases in marrow granulopoiesis were noted. Variable but inconsistent changes in marrow and splenic progenitor cells were noted. Serum CSF was elevated 2 hours after injection but returned to baseline values within 4-6 hours. These studies indicate essentially no effect from exogenous administration of purified CSF; however, higher doses of this factor will be required in further studies.     

On the stimulating effect of drying a soil and the retarding effect of drying a plant material

Summary According to the chemical hypothesis the decomposition of organic matter in soil is affected by the availability of the protons in the soil environment. Drying of a soil increases the proton supply from residual water and thus increases the mineralization of soil organic matter. On the other hand, drying of a fresh plant material saves the organic colloids from protons and thus decreases their subsequent mineralization in soil.     

The osteogenic stimulating effect of neuroactive calcitonin gene-related peptide

Silverman and Kruger (Somatosens. Res. 5(2):157-175; 1987) reported that sensory nerve fibers of the dental pulp secrete calcitonin gene-related peptide (CGRP). These are localized exactly where secondary or tertiary dentin calcification occurs. Recently we found that CGRP has an osteogenic stimulating effect by increasing the number and size of bone colonies in vitro. The purpose of this study is to test whether there is a relationship between the effects of different doses of CGRP and bone colony numbers and/or size. Rat CGRP in different dosages (0.4, 4 and 40 micrograms/ml in BGJb medium) was added daily to 3 million light density (LD) bone marrow white cells which were harvested from adult Sprague-Dawley rats with the Ficoll-Paque density gradient separation method, then seeded onto a previously prepared feeder layer of fibroblasts in Petri dishes. Seven days after adding CGRP, in the controls without CGRP there were 2 bone colonies; with 0.4 microgram of CGRP there were 4 colonies; with 4 micrograms of CGRP there were 6 colonies; with 40 micrograms there were 9 colonies, indicating there was a significant increase in number of bone colonies with an increase in dose of CGRP between individual groups, respectively (p less than 0.0005 and p less than 0.0001). In another experiment, intravenous injection of 10 micrograms of rCGRP/kg body weight was performed two hours before surgery. LD bone marrow white cells were collected and seeded onto a feeder layer in Petri dishes exactly as described above.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of alpha-melanocyte stimulating hormone on colonic inflammation in the rat

The effect of alpha-melanocyte stimulating hormone (alpha-MSH) on colonic inflammation in the rat. In this study, we investigated the effects of alpha-MSH administration on trinitrobenzene sulfonic acid-induced colitis and the role of nitric oxide and prostaglandins in this response. alpha-MSH treatment (25 microg/rat, intraperitoneally; twice daily for 3 days) reduced the colonic macroscopic lesions compared to untreated ones in both acute and chronic colitis groups. This effect was reversed by pretreatment with the nitric oxide donor, sodium NP (4 mg/kg, intravenously) or cyclooxygenase-1 selective antagonist indomethacin (5 mg/kg, subcutaneously) in the acute group and with the cyclooxygenase-2 selective antagonist nimesulide (3 mg/kg, subcutaneously) in the chronic group. alpha-MSH had no effect on colonic wet weight and myeloperoxidase activity compared to the untreated colitis group. However, protein oxidation was markedly elevated in the alpha-MSH-treated group compared to untreated ones. Nitroprusside and indomethacin reversed the effect of alpha-MSH on macroscopic lesions in the acute groups, whereas nimesulide showed a similar effect in the chronic group. In conclusion, the results of our study show a protective role of alpha-MSH on colonic lesions which partially involves nitric oxide and prostaglandins.     

Prostaglandin production by melanocytic cells and the effect of alpha-melanocyte stimulating hormone

Prostaglandins are potent mediators of the inflammatory response and are also involved in cancer development. In this study, we show that human melanocytes and FM55 melanoma cells express cyclooxygenase-1 and -2 (COX-1 and -2) and thus have the capability to produce prostaglandins. The FM55 cells produced predominantly PGE2 and PGF2alpha, whereas the HaCaT keratinocyte cell line produced mainly PGE2. The anti-inflammatory peptide, alpha-melanocyte stimulating hormone (alpha-MSH), reduced prostaglandin production in FM55 and HaCaT cells and reversed the effect of the pro-inflammatory cytokine TNF-alpha in the former. These results indicate that melanocytes produce prostaglandins and that alpha-MSH, by inhibiting this response, may play an important role in regulating inflammatory responses in the skin.