Experimental study on the role of endotoxin in the development of hepatopulmonary syndrome.

AIM: To evaluate the role of intestinal endotoxemia in the genesis of hepatopulmonary syndrome. METHODS: A rat model of cirrhosis was prepared with the method of compound factors. At the end of the eighth week, rats with cirrhosis were treated with 300 microg LPS/100 g body weight, and 1 g/rat of glycine about four h prior to LPS. After three h of LPS treatment, blood and tissues were collected for various measurements. Kupffer cells were isolated from male Wistar rats and cultured, and divided into five groups. Supernatant was harvested at 3 h after treatment with LPS for measurement of tumor necrosis factor-alpha (TNF-alpha). RESULTS: Our results showed that in rats with cirrhosis, slowed and deepened breath with occasional pause was. PaO2, PaCO2 and standard bicarbonate (SB) in arterial blood were decreased. Arterial O2 and actual bicarbonate (AB) were markedly decreased. There was a close correlation between decreased O2 and endotoxin. Metabolic acidosis accompanying respiratory alkalosis was the primary type of acid-base imbalance. The alveolar-arterial oxygen gradient was sharply widened. Massive accumulation of giant macrophages in the alveolar spaces and its wall and widened alveolar wall architecture were observed. The number of bacterial translocations in mesenteric lymph nodes increased. The ratio of TC99M-MAA brain-over-lung radioactivity rose. Endotoxin, and TNF-alpha, endothelin-1 (ET-1), nitric oxide (NO) in plasma and ET-1, carbon monoxide (CO) in lung homogenates increased. After administration of a given dosage of LPS in rats with cirrhosis, various pathological parameters worsened. Plasma level of endotoxin was related to TNF-alpha, ET-1, NO in plasma and ET-1, NO, CO in lung homogenates. TNF-alpha level was related to ET-1 and NO in plasma and lung homogenates and CO in lung homogenate as well. The level of TNF-alpha increased after infusion of LPS into culture supernatant of Kupffer cells in vitro. However, TNF-alpha significantly decreased after pretreatment with glycine, PD98059 and SB212850. Glycine could antagonize the effect of LPS in vivo and in vitro. CONCLUSION: Intestinal endotoxemia accompanying by cirrhosis may be an important mechanism in the development of hepatopulmonary syndrome in rats. Overproduction of TNF-alpha due to endotoxin stimulation of Kupffer cells via mitogen-activated protein kinase (MAPK) signal transduction pathway may be a major mechanism mediating the pathologic alterations of hepatopulmonary syndrome.

Synthesis and characterisation of galactosyl glycerol by ß-galactosidase catalysed reverse hydrolysis of galactose and glycerol.

A study of an enzymatic method for the production of galactosylglycerol is described. The effects of enzyme sources, enzyme amount, reaction temperature, reaction time, substrate ratio of glycerol to galactose, buffer content and pH on galactosylglycerol yield (mg/ml) were investigated. Under the optimum reaction conditions of ß-galactosidases from Kluyveromyces lactis 240 U/ml, temperature 40 °C, time 24 h, buffer amount 60% (percent volume of buffer to that of substrates, pH 6.5), and the substrate molar ratio of 10 (glycerol16 mmol:galactose 1.6 mmol), the yield of galactosylglycerol was up to 116.47 mg/ml (galactose conversion 55.88%). The product was purified by activated charcoal and Sephadex G-15 column chromatography, up to 96%. The purified galactosylglycerol was fully characterised by MS and NMR, and identified as a mixture of (2R)- and (2S)- 3-O-ß-D-galactopyranosyl-glycerol.

Antifungal activity and mechanism of fengycin in the presence and absence of commercial surfactin against Rhizopus stolonifer.

The antifungal activity and mechanism of fengycin in the presence and absence of commercial surfactin against Rhizopus stolonifer were investigated. The MIC (minimal inhibitory concentration) of fengycin without commercial surfactin added was 0.4 mg/ml while the MIC of fengycin with commercial surfactin added was 2.0 mg/ml. Fengycin acted on cell membrane and cellular organs and inhibited DNA synthesis. The antifungal effect of fengycin was reduced after commercial surfactin was added. All these results suggest that the fungal cell membrane may be the primary target of fengycin action and commercial surfactin may reduce the antifungal activity of fengycin.

[Production of functional lipids by lipase-catalyzed acidolysis of lard in solvent free system].

China has richly and inexpensive fat and oils from animal and plants, but these resources could not get effectively utilization. In order to make the best of these resources, lipase-catalyzed acidolysis of lard with caprylic acid to produce functional lipid in solvent free system was investigated. Of the five lipases that were tested in the initial screening, immobilized lipase TL IM fromca T. languginosa resulted in the highest incorporation of capry lic acid into lard. This enzyme was further studied for the effect of enzyme load, substrate ratib, reaction time, reaction temperature and added water content on the incorporation of caprylic acid into lard. HPLC analyzed the products from the acidolysis reaction. The highest incorporation was attained at 20% enzyme load. Time course studied suggest that the incorporation of caprylic acid into lard was increased up to 38.77 mol% after 24h. Desirable mole ratio of substrates was 1:2 (lard: caprylic acid), caprylic acid incorporation up to 30.95 mol%. In the range of 45 - 60 degrees C , temperature had no significant effect on enzyme activity and caprylic acid incorporation changed little. When temperature was above 60 degrees C, incorporation of caprylic acid into lard was decreased. The highest incorporation of caprylic acid into lard 35.76 mol% was attained when added water content was 2.5%.

[Ecological water requirement of forests in Loess Plateau].

Converting degraded farmlands to forest or grass lands is the best approach to reduce the soil erosion, the Loess Plateau is faced with most serious ecological disaster. Loess Plateau located in the arid and semi-arid regions is a fragile region with the characteristics of little precipitation and intensive evapotranspiration. Therefore, water is the most important factor limiting the eco-restoration and construction of the vegetation in the region. According to the latest digital land use map and with GIS, the ecological water requirement for forests in Loess Plateau was estimated, and by the water balance of the forest ecosystem in their growing season, the ecological water shortage was calculated. The results revealed that the minimum and suitable ecological water requirement of the forests in Loess Plateau were approximately 262.49 x 10(8) m3 and 421.34 x 10(8) m3 respectively. Accordingly, if it is taken the minimum ecological water requirement as the quota, the area of forests suffered water shortage was about 7,639.09 km2, 9.1% of all, and the ecological water shortage was amounted to 4.77 x 10(8) m3; if it is taken the suitable ecological water requirement as the quota, the forest land area suffered water shortage was about 57.7% of all, and the ecological water shortage was roughly 58.55 x 10(8) m3.