[Shrub layer structure and species diversity of warm temperate deciduous broadleaved forests of the Qinling Mountains Huangguan plot in China]. / ç§¦å²­çš‡å† æš–æ¸©å¸¦è½å¶é˜”å¶æž—çŒæœ¨å±‚ç»“æž„ä¸Žç‰©ç§å¤šæ ·æ€§.

Shrub is an important part of forest ecosystem. Exploring the species composition, structure and spatial distribution of shrub layer can lay an important foundation for further clarifying the mechanisms underlying species coexistence, biodiversity maintenance and community succession. In this study, species composition, spatial distribution, and species diversity of shrub layer were analyzed in 25 hm2 of Huangguan forest plot. A total of 20716 individual shrubs (with 10463 branches) were recorded in the plot, belonging to 54 species, 45 genera, 28 families. The status of dominant species in the shrub layer was not obvious, with all the importance values being less than 10. The diameter structure of shrub layer vegetation was inverted 'J' type. Shrubs showed aggregated distribution in the plot, with obvious altitude differences in spatial distribution. The diameter structure and spatial distribution of the nine shrub species with the largest abundance in the plot were consistent with the overall situation of shrub layer. With increasing altitude, the Shannon diversity index (H) and Simpson dominance index (D) did not change significantly, while the Pielou evenness index (E) decreased. Those indices decreased with the increases of the abundance of dominant species in tree layer, and E increased with the increase of the number of dominant species in sub-tree layer. The indices of H, D, E were significantly negatively correlated with soil total phosphorus (TP). The H index was significantly positively correlated with soil pH, and the E index was significantly positively correlated with soil total potassium. The shrub layer was rich in species, stable in community structure and well regenerated. The species diversity of shrub layer was mainly affected by the number of dominant species in the tree layer, soil pH, and TP.

The role of nutritional status on serum immunoglobulins, body weight and postoperative infectious-related complications in patients with Crohn's disease receiving perioperative parenteral nutrition / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the role of nutritional status on serum immunoglobulins, body weight and postoperative infectious-related complications in patients with Crohn's disease receiving perioperative parenteral nutrition (PN).</p><p><b>METHODS</b>32 patients with Crohn's disease receiving perioperative parenteral nutrition in our department between 1984 and 1994 were enrolled in this survey. 16 patients with loss of body weight in the range of 15%-30% were assigned to the malnutrition group, the other 16 patients with normal weight or loss of body weight less than 15% to the control group. Serum IgM, IgG and IgA levels were measured before and after PN by enzyme-linked immunosorbent assays. Liver function, body weight changes and postoperative complications were also analyzed.</p><p><b>RESULTS</b>IgM levels were elevated before PN in both groups [control group: (133 +/- 16) mg/dl, malnutrition group: (139 +/- 41) mg/dl; normal value: (110 +/- 35) mg/dl; P = 0.04], decreased to normal value [(105 +/- 29) mg/dl, P = 0.02] in the malnutrition group while having no obvious changes in the control group [(129 +/- 13) mg/dl, P = 0.34]. No significant changes in concentrations of IgG and IgA were found (P in the range of 0.20-0.57). The average weight gain was 1.862 kg in malnutrition group [before PN: (45.8 +/- 8.9) kg, after PN: (48.0 +/- 8.8) kg; P = 0.005] and no significant changes in the control group [before PN: (55.6 +/- 6.1) kg, after PN: (56.3 +/- 6.0) kg; P = 0.46]. There was an increase in infectious complications in the control group (control group: 4 cases, 25%, malnourished group: 2 cases, 12.5%; P = 0.13).</p><p><b>CONCLUSIONS</b>Perioperative parenteral nutrition ameliorated the humoral immunity, increased the body weight in patients with obvious malnutrition, whereas it had little value for those without or with mild malnutrition.</p>

Assay of carnitine in plasma and urine of healthy adults / 中国医学科学院学报

<p><b>OBJECTIVE</b>To determine the levels of carnitine in plasma and daily excretion of carnitine in urine of healthy adults so as to provide the reference standard for studying the changes of carnitine in patients.</p><p><b>METHODS</b>Carnitine in plasma and urine was assayed with high performance liquid chromatography (HPLC). The levels of total carnitine (TC), free carnitine (FC) and acetyl-carnitine (AC) in fasting plasma and the daily excretion of TC, FC and AC in urine were assayed in 40 healthy adults (20 men and 20 women) with standard diet.</p><p><b>RESULTS</b>Good linearity (r 2 > or = 0.999) was observed in assaying TC, FC and AC. The relative standard deviation (RSD) was lower than 9.1% and bias lower than 5.6%. It was showed that the plasmatic levels of TC, FC and AC in healthy men [(53.1 +/- 8.5), (41.2 +/- 6.1), (6.2 +/- 0.6) mumol/L] were significantly higher than those in healthy women [(45.4 +/- 5.6), (35.2 +/- 4.9), (5.7 +/- 0.7) mumol/L] (P = 0.002, 0.002, 0.035). The daily urinary excretion of TC, FC and AC in healthy men [(386.1 +/- 22.9), (180.5 +/- 31.8), (33.8 +/- 3.3) mumol] were also significantly higher than those in healthy women [(240.1 +/- 35.6), (112.7 +/- 22.6), (29.3 +/- 4.3) mumol] (P < 0.0005, < 0.0005, < 0.0005) when the adults were given standard diet. Both the plasmatic levels and the daily urinary excretion of TC, FC and AC were of significantly positive correlation with lean body mass (LBM) (r = 0.501-0.856). The (TC-FC)/FC ratios in plasma were 0.29 +/- 0.05 for male and 0.29 +/- 0.04 for female.</p><p><b>CONCLUSION</b>Good precision and accuracy were observed in assaying carnitine with HPLC. After standard diet, both the level of carnitine in fasting plasma and the daily urinary carnitine excretion of healthy adults were positively correlated with LBM.</p>