Spontaneous multivessel coronary artery spasm: a case report.

A 60-year-old male presented to the emergency department of our hospital with persistent dull pain in the lower and middle sternum with generalized sweating after a heated argument with another person, and his symptoms did not resolve after 3 hours of onset.

[Nutrient uptake strategy selection by first-order roots of Juglans mandshurica under shading and phosphorus limitation]. / 遮阴和磷限制下胡桃楸1çº§æ ¹å »åˆ†å¸æ”¶ç­–ç•¥é€‰æ‹©.

We investigated root growth of 1-year-old Juglans mandshurica seedlings under different light environments and varying doses of phosphorus fertilizer, to understand the relationship between root resource acquisition strategies and the variations of light and phosphorus availability. There were four shading intensities (full light, 65% full light, 35% full light, and 20% full light) along with three doses of phosphate fertilizer (0 (CK), 200% soil background available phosphorus, and 500% soil background available phosphorus). We measured in root morphology characteristics, architectural characteristics, and mycorrhizal colonization rates of first-order roots. The results showed that average diameter, average root length, and mycorrhizal colonization rates of first-order roots gradually decreased, and the specific root length, specific surface area, branching ratio and branching intensity showed a trend of first increasing and then decreasing with the increases of shading degree. As the phosphorus content decreased, the first-order root diameter gradually became thinner, and the mycorrhizal infection rate gradually increased. Root morphology and architecture of J. mandshurica would undergo adaptive changes under shade, adapting to the shading environment by expanding specific root length, specific surface area, branching ratio and branching intensity. Under phosphorus limitation, root system of J. mandshurica would increase phosphorus absorption through symbiosis with mycorrhizal fungi. When J. mandshurica was artificially regenerate in forest land with a light transmittance of 35%, root morphology and architecture would adapt to the shading environment. The symbiosis between J. mandshurica and mycorrhizal fungi would be enhanced under phosphorus limitation, which could improve phosphorus absorption of roots.

Lower Baseline LDL Cholesterol Affects All-cause Mortality in Patients with First Percutaneous Coronary Intervention.

Objective: Foreign studies have reported that coronary artery disease (CAD) patients with high baseline low-density lipoprotein cholesterol (LDL-C) may have a good prognosis, which is called the "cholesterol paradox". This study aimed to examine whether the "cholesterol paradox" also exists in the Chinese population. Methods: A total of 2,056 patients who underwent the first percutaneous coronary intervention (PCI) between 2014 and 2016 were enrolled in this retrospective cohort study and classified into two groups based on baseline LDL-C = 2.6 mmol/L (100 mg/dL). The outcomes of interest included major adverse cardiovascular events (MACE), all-cause mortality, recurrent nonfatal myocardial infarction, unexpected coronary revascularization, or any nonfatal stroke. Results: All-cause mortality occurred in 8 patients (0.7%) from the low-LDL-C group and 12 patients (2.4%) in the high-LDL-C group, with a significant difference between the two groups (adjusted hazard ratio: 4.030, 95% confidence interval: 1.088-14.934; P = 0.037). However, no significant differences existed for the risk of MACE or other secondary endpoints, such as unexpected revascularization, nor any nonfatal stroke in the two groups. Conclusion: In this study, a high baseline LDL-C was not associated with a low risk of clinical outcomes in CAD patients undergoing first PCI, which suggested that the "cholesterol paradox" may be inapplicable to Chinese populations.

An immunotoxin with greatly reduced immunogenicity by identification and removal of B cell epitopes.

Recombinant immunotoxins are hybrid proteins composed of an Fv that binds to a tumor antigen fused to a bacterial or plant toxin. Immunotoxin BL22 targets CD22 positive malignancies and is composed of an anti-CD22 Fv fused to a 38-kDa fragment of Pseudomonas exotoxin A (PE38). BL22 has produced many complete remissions in drug-resistant Hairy cell leukemia, where many treatment cycles can be given, because neutralizing antibodies do not form. In marked contrast, only minor responses have been observed in trials with immunotoxins targeting solid tumors, because only a single treatment cycle can be given before antibodies develop. To allow more treatment cycles and increase efficacy, we have produced a less immunogenic immunotoxin by identifying and eliminating most of the B cell epitopes on PE38. This was accomplished by mutation of specific large hydrophilic amino acids (Arg, Gln, Glu, Lys) to Ala, Ser, or Gly. The new immunotoxin (HA22-8X) is significantly less immunogenic in three strains of mice, yet retains full cytotoxic and anti-tumor activities. Elimination of B-cell epitopes is a promising approach to the production of less immunogenic proteins for therapeutic purposes.

[Root architecture and fine root characteristics of Juglans mandshurica saplings in different habitats in the secondary forest on the west slope of Zhangguangcailing, China]. / å¼ å¹¿æ‰å²­è¥¿å¡æ¬¡ç”Ÿæž—ä¸åŒç”Ÿå¢ƒèƒ¡æ¡ƒæ¥¸å¹¼æ ‘æ ¹ç³»æž„åž‹åŠç»†æ ¹ç‰¹å¾.

The whole root excavation method was used to examine root configuration of Juglans mandshurica, with the age of 5-6 years in three habitats (forest edge, gap, and canopy) in a secondary forest on the western part of Zhangguangcailing Mountains. Root structure and fine root function were measured. The root topological index, average joint length, cross-sectional area ratio before and after root branching were calculated and fine root chemical compositions were analyzed. Roots of J. mandshurica at forest edge tended to be dichotomous branch (Topological index:TI=0.68), that under the canopy were herringbone-like branch (TI=0.79), and the gap was between the two (TI=0.72). The average connection length of roots among the three habitats was not significant. The cross-sectional area ratio of roots before and after root branching in three habitats was 1.06, 1.04 and 1.07, respectively, which was not affected by root diameter, in accordance with the Leonardo da Vinci rule. For the same order fine root in different habitats, its length and specific surface area gradually increased from the edge of the forest to the canopy. The N content decreased first and then increased, while the C content and C/N increased first and then decreased. From the forest edge to the gap and to the under canopy, roots tended to move from the dichotomous branch to the herringbone-like branch by reducing the overlap between the secondary branches and roots, increasing specific root length, specific surface area and changing the contents of C and N to cope with environmental change and improve nutrient absorption efficiency.

Anti-HIV-1 immunotoxin 3B3(Fv)-PE38: enhanced potency against clinical isolates in human PBMCs and macrophages, and negligible hepatotoxicity in macaques.

Highly active antiretroviral therapy (HAART) against human immunodeficiency virus type 1 (HIV-1) infection dramatically suppresses viral load, leading to marked reductions in HIV-1 associated morbidity and mortality. However, infected cell reservoirs and low-level replication persist in the face of suppressive HAART, leading invariably to viral rebound upon cessation of treatment. Toxins engineered to target the Env glycoprotein on the surface of productively infected cells represent a complementary strategy to deplete these reservoirs. We described previously highly selective killing of Env-expressing cell lines by CD4(178)-PE40 and 3B3(Fv)-PE38, recombinant derivatives of Pseudomonas aeruginosa exotoxin A containing distinct targeting moieties against gp120. In the present report, we compare the in vitro potency and breadth of these chimeric toxins against multiple clinical HIV-1 isolates, replicating in biologically relevant primary human target cell types. In PBMCs, 3B3(Fv)-PE38 blocked spreading infection by all isolates examined, with greater potency than CD4(178)-PE40. 3B3(Fv)-PE38 also potently inhibited spreading HIV-1 infection in primary macrophages. Control experiments demonstrated that in both target cell types, most of the 3B3(Fv)-PE38 activity was due to selective killing of infected cells, and not merely to neutralization by the antibody moiety of the chimeric toxin. High-dose treatment of rhesus macaques with 3B3(Fv)-PE38 did not induce liver toxicity, whereas equivalent dosage of CD4(178)-PE40 induced mild hepatotoxicity. These findings highlight the potential use of 3B3(Fv)-PE38 for depleting HIV-infected cell reservoirs persisting in the face of HAART.

[Absorption characteristics of FRLP-Cu(II) metal complexes].

The technical pure azo dye FRL was purified by recrystallization with the solvent composed of ethanol and water whose volume ratio is 1:1. The azo dye FRLP was obtained by coincidence reaction with phen after reoxidation reaction by purified FRL and sodium nitrite, which can be cooperated with Cu2+. And at room temperature the UV-Vis spectrum of FRLP-Cu2+ was studied. The form of the complex was confirmed by successive changing equal number of moles, which is in the B-R solution from pH 6 to pH 9, and the ratio of the complex (Cu2+:FRLP) is 1:2. In the B-R solution (pH 8.8) the mol absorption parameter of the complex is epsilon590 nm = 9.5 x 10(4) L x mol(-1) x cm(-1), and the apparent stable constant is K = 5.12 x 10(12). The property of ultraviolet band spectrum of FRLP-Cu2+ was studied, showing that the aqueous solution of the complex can absorb the ultraviolet radiation strongly from 200 nm to 305 nm. The complex mixing with PVAL can also absorb ultraviolet radiation strongly. At the maximum absorption wavelength in the visible zone and laid parallelly with the optical axis, the transmission of the single slice is 45%-50%, the transmission of two slices laid vertically is zero from 200 nm to 325 nm, and the averaged transmission from 325 nm to 400 nm is 10%.

Humoral immune response to mesothelin in mesothelioma and ovarian cancer patients.

PURPOSE: Mesothelin is a glycosyl-phosphatidylinositol-anchored glycoprotein present on the cell surface. Mesothelin is a differentiation antigen that is highly expressed on mesothelioma, ovarian cancer, and pancreatic cancer. The existence of a spontaneous humoral immune response to mesothelin in humans has not been fully studied. Here we addressed the issue of whether mesothelin elicits a humoral immune response in patients with mesothelioma and ovarian cancer. EXPERIMENTAL DESIGN: Using an ELISA, we analyzed immunoglobulin G antibodies specific for mesothelin in sera from patients with mesothelioma and epithelial ovarian cancer. Tumor specimens were examined by immunohistochemistry for mesothelin protein expression. RESULTS: Elevated levels of mesothelin-specific antibodies were detected in the sera of 39.1% of patients with mesothelioma (27 of 69 patients) and 41.7% with epithelial ovarian cancer (10 of 24 patients) when compared with a normal control population (44 blood donors; P < 0.01 for both mesothelioma and ovarian cancer). We also found that 53% to 56% of patients with mesothelin immunostaining-positive mesothelioma and ovarian cancer had antibodies specific for mesothelin, whereas only 0% to 8% of patients with negative mesothelin immunostaining had detectable mesothelin-specific antibodies (chi(2) test: P < 0.01 for mesothelioma and P = 0.025 for ovarian cancer). CONCLUSIONS: Our findings indicate that mesothelin is a new tumor antigen in patients with mesothelioma and ovarian cancer and the immunogenicity of mesothelin is associated with its high expression on the tumor cells. Mesothelin represents an excellent target for immune-based therapies.

In vitro and in vivo cytotoxic activities of recombinant immunotoxin 8H9(Fv)-PE38 against breast cancer, osteosarcoma, and neuroblastoma.

The 8H9 monoclonal antibody (MAb) is highly reactive with a cell surface glycoprotein expressed on human breast cancers, childhood sarcomas, and neuroblastomas but is not reactive with the cell surface of normal human tissues. This specific reactivity suggests that MAb 8H9 may be useful for targeted cancer therapy. To explore this possibility, we generated two recombinant immunotoxins (ITs) using the single-chain Fv (scFv) of MAb 8H9. Initially the 8H9(scFv) cDNA was fused to a DNA encoding a 38-kDa truncated form of Pseudomonas exotoxin (PE38) to generate the IT 8H9(scFv)-PE38. The fusion gene was expressed in Escherichia coli, and the IT was purified to near homogeneity from inclusion bodies. The purified IT showed specific cytotoxicity on nine different cancer cell lines derived from breast cancer, osteosarcoma, and neuroblastomas, known to react with MAb 8H9. The cytotoxic activity was inhibited by MAb 8H9, showing the cytotoxic activity is specific. The antitumor activity of 8H9(scFv)-PE38 was evaluated in severe combined immunodeficient mice bearing MCF-7 breast cancers or OHS-M1 osteosarcomas. The IT showed a specific dose-dependent antitumor activity at 0.075 and 0.15 mg/kg. Next, a more stable disulfide-linked IT, 8H9(dsFv)-PE38, was constructed. It was produced in high yield (16%) and showed cytotoxic and antitumor activities similar to those of 8H9(scFv)-PE38. 8H9(dsFv)-PE38 was given to two cynomolgus monkeys at doses of 0.1 and 0.2 mg/kg i.v. QOD x 3 and was well tolerated. This shows that a dose that causes significant tumor regressions in mice is well tolerated by monkeys. These results make 8H9(dsFv)-PE38 a candidate for further development as a therapeutic agent for breast cancers, osteosarcomas, and neuroblastomas.

[Fluorescence study on the interaction of alizarin yellow R and bovine serum albumin in alkali solution].

The interaction of alizarin yellow R(AYR) and bovine serum albumin (BSA) was investigated by fluorescence method in alkali buffer solution. It was shown that AYR had a powerful ability to quench the BSA fluorescence at excitation and emission wavelengths of lambda(ex) = 393 nm and lambda(em) = 641 nm in the medium solution of pH 11.00, and there were five binding sites of AYR to BSA; The combination reaction of AYR with BSA was a static quenching process, and from the effects of temperature on the fluorescence quenching rate of AYR-BSA and the Stern-Volmer quenching constant (K(SV)) and the Lineweaver-Burk quenching constant (K(LB)), the binding constant was calculated to be K = 1.6 x 10(4) L x mol(-1); as the enthalpy change deltaH(theta) < 0 and entropy change deltaS(theta) < 0, and AYR has an ability to quench the BSA-CBBG fluorescence, it can be deduced that the Van der Walls force and hydrogen bond are the main binding forces between AYR and BSA.

Antitumor activity of SS(dsFv)PE38 and SS1(dsFv)PE38, recombinant antimesothelin immunotoxins against human gynecologic cancers grown in organotypic culture in vitro.

PURPOSE: Mesothelin, a cell surface glycoprotein overexpressed in ovarian cancer, mesotheliomas, and some squamous cell carcinomas, is an attractive candidate for targeted therapy because it is not shed in significant amounts into the bloodstream and is not present in significant amounts on normal human tissues except for mesothelial cells. The objective of this study was to determine the antitumor activity of SS1(dsFv)PE38, a recombinant antimesothelin immunotoxin, against human gynecologic tumors grown in short-term culture in vitro. EXPERIMENTAL DESIGN: Tumor cells obtained from primary cultures of five ovarian and one cervical tumor were mixed with an equal proportion of NIH-3T3 fibroblasts and plated inside collagen gels in tissue culture plates. After 4-7 days of growth, these organotypic cultures were treated with media alone, SS1(dsFv)PE38, and a control immunotoxin RFB4(dsFv)PE38, which targets the CD22 antigen not present on gynecologic tumors, every other day x 3. The organotypic culture gels were then formalin fixed, paraffin embedded, and evaluated for immunotoxin sensitivity using light microscopic examination of H&E-stained slides and also evaluated for apoptosis using the terminal deoxynucleotidyl transferase-mediated nick end labeling assay. RESULTS: Tumors expressing mesothelin showed a significant dose-dependent sensitivity to SS1(dsFv)PE38 even at concentrations as low as 1 ng/ml, whereas no antitumor activity was seen at 100 ng/ml in tumors that did not express mesothelin. This activity was specifically attributable to mesothelin targeting because RFB4 (dsFv)-PE38 had no activity against mesothelin-expressing tumors. CONCLUSIONS: These results demonstrate that ovarian and cervical tumor cells obtained from patients can be grown in short-term culture using an organotypic culture model. Our results also show low concentrations of an immunotoxin targeting mesothelin is cytotoxic to mesothelin-expressing human tumors by inducing apoptosis.

Abrogation of head and neck squamous cell carcinoma growth by epidermal growth factor receptor ligand fused to pseudomonas exotoxin transforming growth factor alpha-PE38.

PURPOSE: This study was undertaken to determine whether low intratumoral doses of the epidermal growth factor receptor ligand-transforming growth factor alpha (TGF-alpha) fused to Pseudomonas exotoxin (TGF-alpha-PE38)-abrogated head and neck squamous cell carcinoma (HNSCC) tumor growth in vitro and in vivo. EXPERIMENTAL DESIGN: In vitro cytotoxicity assays were carried out to determine the sensitivity of HNSCC cells to TGF-alpha-PE38. TGF-alpha-PE38-treated HNSCC cells were examined by immunoblotting for cleaved poly(ADP-ribose) polymerase to evaluate apoptosis. Nude mice bearing established HNSCC xenografts were treated with several doses of TGF-alpha-PE38 to evaluate the antitumor efficacy in vivo. Tumor sections were stained with terminal deoxynucleotidyl transferase-mediated nick end labeling for apoptosis. To determine the effect of oral administration of TGF-alpha-PE38, gavage injections of TGF-alpha-PE38 were administered, and the esophagus and surrounding soft tissue were then stained for apoptotic cells. RESULTS: HNSCC cell lines examined were sensitive to low doses of TGF-alpha-PE38 (EC(50) in the range of 1.6 to 10 ng/mL). HNSCC cells treated with TGF-alpha-PE38 undergo apoptosis. Antitumor effects were observed using 0.1 and 0.03 microg of TGF-alpha-PE38 administered intratumorally. At these doses, the treatment was well tolerated. Tumors treated with the toxin had a higher number of apoptotic cells compared with the control tumors. No apoptotic cells were observed in the pharyngoesophageal tissues of the mice after gavage administration of the toxin suggesting that the toxin could be orally administered without toxicity. CONCLUSIONS: These results indicate that topical or intratumoral administration of low doses of TGF-alpha-PE38 may demonstrate antitumor effects in HNSCC without associated systemic toxicity.

Targeted therapy against human lung cancer in nude mice by high-affinity recombinant antimesothelin single-chain Fv immunotoxin.

Several tumors, including mesothelioma and ovarian cancer, can overexpress mesothelin, a glycosylphosphatidylinositol-linked differentiation glycoprotein. The membrane-bound type of mesothelin is found in the blood of cancer patients at a very low level, which makes mesothelin a good candidate for targeted therapy of certain cancers. An antimesothelin disulfide-linked Fv (SS1 Fv) was fused to a truncated mutant of Pseudomonas exotoxin A to produce the recombinant immunotoxin SS1(dsFv)-PE38, which has a high binding affinity to mesothelin (Kd = 0.7 nM). Our studies in vitro showed that SS1(dsFv)-PE38 is significantly more cytotoxic to the high-mesothelin-producing NCI-H226 human non-small cell lung cancer cells than to human lung adenocarcinoma PC14PE6 cells, which do not express mesothelin. When administered at a nontoxic dose of 500 microg/kg on days 7, 9, and 11 to nude mice injected i.v. with the two human lung cancer cell lines, SS1(dsFv)-PE38 selectively inhibited experimental lung metastases produced by the mesothelin-producing NCI-H226 cells. Our data indicate that mesothelin-producing squamous cell carcinoma of the lung may be a good target for this immunotoxin.

[Interspecific allelopathic effect of different organs' aqueous extracts of Betula platyphylla and Larix olgensis on their seed germination and seedling growth].

In this paper, the Betula platyphylla root-, branch-, and foliage aqueous extracts and Larix olgensis root-, branch-, foliage-, and bark aqueous extracts over a range of concentrations 5.0, 12.5, 25.0, 50.0, and 100.0 mg x mL(-1) were used to study their interspecific allelopathic effect on the seed germination and seedling growth of the two tree species. All the L. olgensis organs' extracts, except its root extracts at concentration 5.0 mg x mL(-1), had inhibition effect on B. platyphylla seed germination rate, which was 54%, 58%, 59%, and 66% under the effects of L. olgensis foliage-, branch-, bark-, and root extracts, respectively, as compared with the control. With increasing concentration, the inhibition effect of L. olgensis root- and branch extracts increased while that of L. olgensis foliage- and bark extracts decreased. The L. olgensis organs' extracts, especially the foliage extracts at concentration 100.0 mg x mL(-1), had strong inhibition effect on B. platyphylla seed radicle- and hypocotyl length growth, with a decrement of 38% and 55% (P < 0.05), respectively. L. olgensis branch- and foliage extracts promoted, but root- and bark extracts inhibited B. platyphylla seedling growth and biomass production. B. platyphylla organs' extracts promoted L. olgensis seed germination, root- and branch extracts promoted hypocotyl length growth, but foliage extracts at 50.0 and 100.0 mg x mL(-1) decreased the hypocotyl length growth by 27% and 28% (P < 0.05), respectively. B. platyphylla organs' extracts mainly promoted L. olgensis seedling growth, with the height- and collar diameter growth and biomass accumulation at B. platyphylla foliage extracts concentration 5.0 mg x mL(-1) increased by 54%, 60%, and 100% (P < 0.05), respectively. Our results suggested that there existed obvious allelopathic effect between B. platyphylla and L. olgensis, and thus, mixed planting B. platyphylla and L. olgensis could have promotion effects on the growth of the two tree species.

[Soil nutrient status of pure birch and larch plantations based on their seedlings bioassay].

One-year-old birch (Betula platyphylla) and larch (Larix olgensis) seedlings were respectively planted in pots with the soils taken from 35-year-old pure birch and larch plantations, and the seedlings growth, biomass increment, foliar nutrient content, and soil nutrient status were monitored, aimed to evaluate the fertility levels of the two soils and the possible interspecific interaction in mixed larch-birch forest. Birch soil had significantly higher contents of total N and available N than larch soil, while larch soil had significantly higher contents of total P, available P, and total K than birch soil (P < 0.05). In the first growth season, the height and collar diameter growth and the biomass accumulation of birch seedlings growing on birch soil were 69%, 52%, and 65% (P < 0.05) higher than those growing on larch soil, and the larch seedlings also had 12%, 8%, and 37% gains of the indices, respectively. The foliar N concentration of both larch and birch seedlings growing on birch soil was higher than that on larch soil, while the foliar P concentration was higher when the seedlings were growing on larch soil than on birch soil. The birch soil had higher content of available N because of the higher litterfall, while the larch soil had greater available P because of the higher P mobilizing effect. It was predicted that in mixed birch-larch forest, the complementary interaction of soil N and P could benefit the growth of the two tree species.

[Effects of exogenous spermidine and spermine on Celastrus orbiculatus antioxidant system under soil NaHCO3 stress].

This paper studied the effects of foliar spraying spermidine and spermine on the leaf antioxidant system of Celastrus orbiculatus under soil NaHCO3 stress. The results showed that under the stress, spraying spermidine and spermine could significantly decrease the leaf O2-* production rate, H2O2 and MDA contents, and electrolyte leakage of C. orbiculatus (P < 0.05). Spraying spermidine increased the leaf SOD, CAT, POD and APX activities and GSH, CAR and Pro contents obviously, but had no effect on leaf AsA content. Spraying spermine also increased leaf POD and APX activities and GSH, CAR and Pro contents obviously, but had lesser effect on leaf SOD activity and AsA content, and even, caused a significant decrease in leaf CAT activity. In the meantime, spermidine and spermine effectively improved the growth of C. orbiculatus seedlings. It was suggested that under soil NaHCO3 stress, exogenous spermidine and spermine could improve the functions of membrane protective system and decrease the O2-* accumulation in C. orbiculatus leaves, and consequently, increase the C. orbiculatus tolerance to NaHCO3 exposure.

[Effects of soil acidity on Pinus resinosa seedlings photosynthesis and chlorophyll fluorescence].

Red pine (Pinus resinosa) is one of the most important tree species for timber plantation in North America, and preliminary success has been achieved in its introduction to the mountainous area of Northeast China since 2004. In order to expand its growth area in other parts of Northeast China, a pot experiment was conducted to study the adaptability of this tree species to varying soil acidity. P. resinosa seedlings were grown in soils with different acidity (pH = 4.5, 5.5, 6.5, 7.5, and 8.0) to test the responses of their photosynthesis and chlorophyll fluorescence parameters to soil pH levels, and the appropriate soil acidity was evaluated. Dramatic responses in chlorophyll a and b contents, Pn and chlorophyll fluorescence parameters (Fo, Fm, Fv, Fv/Fm, and phi(PS II)) were detected under different soil acidity (P < 0.05), with the highest chlorophyll content and Pn under soil pH 5.5, and significantly lower chlorophyll content and Pn under soil pH 7.5 and 8.0. The chlorophyll content and Pn were 41% and 50%, and 61% and 88% higher under soil pH 5.5 than under soil pH 7.5 and 8.0. The seedlings had a significant photosynthetic inhibition under soil pH 7.5 and 8.0, but the highest Fv/Fm and phi (PS II) under soil pH 5.5. Comparing with those under soil pH 7.5 and 8.0, the Fv/Fm and phi (PS II) under soil pH 5.5 were 8% and 12%, and 22% and 35% higher, respectively. It was suggested that soil pH 5.5 was most appropriate for P. resinosa growth.

[Soil nutrient leaching patterns in maize field under different fertilizations: an in situ study].

An in situ field experiment with lysimeter was conducted to study the effects of different fertilizations on the nutrient leaching loss from brown soil in the growth season of summer maize. The results showed that abundant rainfall and irrigation were the main factors affecting the leaching loss. The leaching amount was higher in the early growth period of summer maize, but decreased after then. The difference among different fertilization treatments also decreased with maize growth. Comparing with N fertilization, wheat stalk plus N application intensified the leaching. During the growth period of summer maize, the NO3- -N content in leached water in fertilization treatments had two peaks, while the NH4+ -N content had a trend of increased first and decreased then. The leaching loss of soil N was mainly in the form of NO3- -N. The accumulative leaching loss of NO3- -N was 12.90-46.53 kg * hm(-2), and that of NH4+ -N was 1.66-5.11 kg x hm(-2), both of which increased with increasing N application rate. The leaching rate of soil N was 6.53%-13.07% higher in treatment wheat stalk plus N application than in treatments of N fertilization, and 3.66%-10.10% higher in low N treatments than in high N treatments. The accumulative leaching loss of available P was only 0.148-0.235 kg x hm(-2), while that of available K was 7.08-13.00 kg x hm(-2). In the late growth period of summer maize, wheat stalk plus N application increased the leaching loss of soil available P and K, while nitrogen application affected it slightly.