Hepatoma-derived growth factor supports the antiapoptosis and profibrosis of pancreatic stellate cells

Pancreatic cancer is refractory and is characterized by extensively surrounding and intratumor fibrotic reactions that are contributed by activated pancreatic stellate cells (PSCs). Herein, we show that CCAAT/enhancer-binding protein δ (CEBPD) responds to transforming growth factor-β1 (TGF-β1) through reciprocal loop regulation and that activated hypoxia inducible factor-1α (HIF-1α) further contributes to the upregulation of the hepatoma-derived growth factor (HDGF) gene. Secreted HDGF contributes to the antiapoptosis of PSCs and consequently leads to the synthesis and deposition of extracellular matrix proteins for stabilizing PSC/pancreatic cancer cell (PCC) tumor foci. This result agrees with the observation that severe stromal growth positively correlated with stromal HDGF and CEBPD expression in pancreatic cancer specimens. Collectively, the identification of the TGF-β1-activated CEBPD/HIF-1α/HDGF axis provides new insights into novel discoveries of HDGF in the antiapoptosis and profibrosis of PSCs and the outgrowth of PCCs.

Effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme in bean (Phaseolus vulgaris L.) grown under different nitrogen conditions

The effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme have been examined in different cultivars of Phaseolous vulgaris L. grown under 1 and 12 mM nitrogen. Low nitrogen nutrition reduces chlorophyll and soluble protein contents in the leaves and thus the photosynthesis rate and dry-matter accumulation. Chlorophyll, soluble protein and Rubisco contents and photosynthesis rate are not significantly altered by ambient levels of UV-B radiation (17 microW m-2, 290-320 nm, 4 h/day for one week). Comparative studies show that under high nitrogen, UV-B radiation slightly enhances leaf expansion and dry-matter accumulation in cultivar Pinto, but inhibits these parameters in Vilmorin. These results suggest that the UV-B effect on growth is mediated through leaf expansion, which is particularly sensitive to UV-B, and that Pinto is more tolerant than Vilmorin. The effect of UV-B radiation on UV-B-absorbing compounds and on NADP-malic enzyme (NADP-ME) activity is also examined. Both UV-B radiation and low-nitrogen nutrition enhance the content of UV-B-absorbing compounds, and among the three cultivars used, Pinto exhibits the highest increases and Arroz the lowest. The same trend is observed for the specific activity and content of NADP-ME. On a leaf-area basis, the amount of UV-B-absorbing compounds is highly correlated with the enzyme activity (r2 = 0.83), suggesting that NADP-ME plays a key role in biosynthesis of these compounds. Furthermore, the higher sensitivity of Vilmorin than Pinto to UV-B radiation appears to be related to the activity of NADP-ME and the capacity of the plants to accumulate UV-B-absorbing compounds.

Sensitive assays for the determination of monoamine oxidase and phenol sulphotransferase activity in small tissue samples

A method to assay phenol sulphotransferase (PST) and monoamine oxidase (MAO) in brain (anterior pituitary gland, hypothalamus) and liver specimens as small as 4 mg is described. The specimens were homogenized (sonicated) in various volumes of a buffer, the smallest being 100 microL, to obtain the homogenates. MAO assay was carried out using 30 microL of the homogenate and for PST assay, 30 microL of either the homogenate or, in the case of liver, the supernatant (100,000 x g for 60 min). The radiolabeled products of the enzymatic reactions were separated from the radiolabeled substrates by high-pressure liquid chromatography (HPLC) and the radioactivity of the eluted products measured directly by a radioisotope detector coupled to the HPLC system. The constraint of the assay protocol was not the weight of the specimens but the volume of buffer used in the preparation of the homogenate. Although 100 microL was a convenient working volume, the tissue can also, with care, be sonicated in a 50 microL buffer. With extremely small specimens, weighed fractions of the specimens could be sonicated directly in the control and experimental incubation mixtures bypassing the preparation of the homogenate. Thus, the overall method offers, for the first time, a reliable and adaptable means for measuring MAO and PST in small to extremely small tissue specimens.

Levels of dopamine and 3,4-dihydroxyphenylacetic acid in the adenohypophysis of normo- and hypertensive rats

The levels of dopamine and its metabolites in the adenohypophysis of the normo- and hypertensive rats were determined. Dopamine was present as the free and sulfate-conjugated form in the adenohypophysis of the spontaneously hypertensive rat (SHR), Wistar Kyoto (WKY) and Sprague-Dawley (SD) rats. The levels of both the free and conjugated dopamine in the adenohypophysis of the SHR were 5.49 +/- 2.91 (mean +/- SEM) and 4.27 +/- 3.31 pmoles/mg protein respectively. These values were not significantly different from those of the WKY and SD. 3,4-Dihydroxyphenylacetic acid (dopac), present as the free and sulfate-conjugated form, was found to be the only metabolite of dopamine in the adenohypophysis of the three animals. The levels of both free and conjugated dopac in the adenohypophysis of the SHR were 7.0 +/- 2.5 and 75.5 +/- 33.5 pmoles/mg protein respectively and these values were significantly different from those of the WKY (1.12 +/- 0.47 and 4.17 +/- 0.48 pmoles/mg protein) and SD (1.87 +/- 0.62 and 3.5 +/- 1.11 pmoles/mg). The results indicate that (a) there is no deficiency of free dopamine in the adenohypophysis of the SHR and hypertension in these animals is unlikely to be related to the catecholamine level in the endocrine gland, (b) the dopamine turnover in either the tuberoinfundibular tract or the adenohypophysis of the SHR is greatly enhanced.

Antihemostatic and antithrombotic effects of capsaicin in comparison with aspirin and indomethacin

Capsaicin prolonged the tail bleeding time in the conscious mice. This effect was dose-dependent and maximal effect was observed at 3 hr after the oral administration. Capsaicin was effective in preventing death caused by ADP-induced acute pulmonary thromboembolism in mice at dose of 25 mg/kg, while aspirin and indomethacin had no effect at 200 mg/kg. Capsaicin also reduced the mortality in collagen- and sodium arachidonate-induced thromboembolic death at dose of 25 and 50 mg/kg, respectively, and aspirin and indomethacin were also effective in these models but only when the dose was higher than 200 mg/kg. Capsaicin, aspirin or indomethacin could not protect mice from endotoxin shock. Capsaicin was found to suppress platelet aggregation markedly, but did not affect blood coagulation. In conclusion, capsaicin was proved to be more effective than aspirin and indomethacin in preventing the death of acute pulmonary thromboembolism, and this effect could be due to its inhibition on platelet aggregation.