两种高质牧草不同生育期光合生理日变化及光响应特征

于2010年5月25日(拔节、分枝期)、7月6日(抽穗、结荚期)、8月25日(开花期)晴朗天气,采用LI-6400便携式光合作用测定系统对新引1号东方山羊豆和柳枝稷各项光合生理生态指标进行了测定。结果表明:(1)新引1号东方山羊豆净光合速率(Pn)日变化呈双峰曲线,存在"光合午休"现象;分枝期Pn、光能利用效率(LUE)、水分利用效率(WUE)日均值高于结荚期,而结荚期的叶温(Tl)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)日均值高于分枝期。(2)柳枝稷的Pn日变化呈单峰曲线,拔节期Pn、Tr日均值高于抽穗期,开花期最低;WUE与Ci日均值在开花期最高,拔节期次之,抽穗期最小;Tl、LUE日均值在抽穗期最高,拔节期次之,开花期最小。(3)Pn与Tr、Gs、叶片气孔限制值(Ls)、光合有效辐射(PAR)具有极显著正相关关系,与Ci呈极显著负相关;Tr与Gs、叶温下蒸汽压亏缺(Vpdl)、气温(Ta)、Tl、PAR均呈极显著正相关关系,与大气CO2浓度(Ca)呈显著负相关;Tl、Gs与PAR呈极显著正相关。(4)通过光响应曲线的绘制及相关生理指标的计算,结合相关评价标准,得出柳枝稷为阳生植物,而新引1号东方山羊豆为耐荫植物,且柳枝稷比新引1号东方山羊豆对光环境的适应性强。     

NaCl胁迫对杂交狗牙根品种‘苏植2号’和‘Tifgreen’生长及Na＋和K＋积累的影响

对0（对照）和20g·L-1NaCl胁迫条件下杂交狗牙根（Cynodondactylon×C.transvaalensis）品种‘苏植2号’（‘SuzhiNo.2’）和‘Tifgreen’不同部位的生长状况以及Na＋和K＋积累的差异进行了研究,并分析了2个品种间Na＋、K＋转运调控机制的差异。结果显示：在NaCl胁迫条件下,2个品种的叶片相对枯黄率、地下茎和根系的相对干质量、叶片和根系的Na＋含量和Na＋/K＋比以及钠钾选择性转运系数增加;修剪茎叶及冠层和地上部的相对干质量、植株相对总干质量以及叶片和根系的K＋含量均降低,但茎叶含水量无显著变化。NaCl胁迫条件下,不同土层中2个品种的根系相对干质量均不同程度增加,且20-40和40-60cm土层中根系干质量的增幅大于0-20cm土层;在0-20cm土层中2个品种根系的分配比例均有所降低,而在20-40和40-60cm土层中则不同程度提高。与‘Tifgreen’相比,NaCl胁迫条件下‘苏植2号’叶片相对枯黄率、Na＋含量和Na＋/K＋比更低,修剪茎叶及冠层和地上部的相对干质量、植株相对总干质量、叶片K＋含量和钠钾选择性转运系数更高;在20-40和40-60cm土层中‘苏植2号’根系相对干质量显著高于‘Tifgreen’,根系分配比例总体也高于‘Tifgreen’。综合比较结果表明：‘苏植2号’的抗盐性强于‘Tifgreen’,可能与其深层根系分配量更高和钠钾选择性转运能力较强有关。     

Relationship between cytotoxicity and DNA damage in mammalian cells treated with anthracenedione derivatives

The effects of two anthracenedione derivatives on in vitro cell survival and DNA of Chinese hamster ovary (CHO) cells were investigated. The two drugs studied were 1,4-dihydroxy-5,8-bis-(2-[2-hydroxyethyl)amino)ethylamino)-9,10-anthracenedione (DHAQ, NSC No. 279836) and 1,4-bis-(2-[2-hydroxyethyl)-amino)ethylamino)-9,10-anthracenedione (HAQ, NSC No. 287513). DHAQ was 100-fold more potent in reducing cell survival than HAQ. DNA strand breaks were assayed by alkaline elution. DHAQ (10 ng/ml) caused more strand breakage than 1000 ng/ml HAQ. This difference correlates well with their differences in ability to kill cells.     

Trypanocidal activity of a nitrovinylfuran derivative (SQ 18,506) in mice

The curative action of trans-5-amino-3[2-(5-nitro-2-furyl)-vinyl]-1,2,4-oxadiazole (SQ 18,506), administered orally to mice infected with Trypanosoma (Trypanozoon) brucei rhodesiense (Wellcome CT strain), was dose- and time-related. The optimal regimen was 200 mg/kg at 12-hr intervals for 3 days, beginning shortly after the mice were inoculated. The earliest manifestation of the action of SQ 18,506 in vivo occurred 36 hr after treatment was begun, exemplified by suppression of trypanosomal reproduction. Trypanocidal effects became evident only after two full days of drug administration. The effectiveness of a relatively coarse formulation of SQ 18,506 (16 μm median particle size) was significantly lower than that of other preparations in which the median particle size was approximately 4 μm. A single intramuscular injection of SQ 18,506 (1 g/kg) given prior to a trypanosomal infection which, if untreated, would kill all the mice within 3.5 days, had a relatively slow onset of prophylactic action, reaching a peak when the interval between treatment and exposure was about 3 days. Prophylactic action essentially disappeared when the interval between treatment and exposure was longer than one week.Biochemical studies in vitro of trypanosomes previously exposed in vivo to SQ 18,506 for increasing periods of time indicated that this compound can inhibit various pathways of trypanosomal nuclec acid and carbohydrate metabolism, the former apparently more sensitive to the effects of the drug than the latter. These suggested modes of action can account for the profile of parasitemia in infected mice to which SQ 18,506 was repeatedly administered, which first showed evidence of suppression of trypanosomal reproduction followed by a precipitous drop in the population.     

Vasopressin does not enhance memory processes: a study in human twins

Behavioral effects of lysin-vasopressin (LVP) were investigated applying two paradigms from human experimental psychology. The first task was designed to simulate amnesic symptoms in normals. The second task addressed the emotional value of the items to be processed. Additionally, EEG recordings were used as indicators of the central nervous system effectiveness of LVP. Blood pressure and heart rate measured peripheral arousal. The co-twin control method was employed to increase experimental power. Contrary to the prediction of the vasopressin memory hypothesis none of the specific memory parameters was improved by LVP treatment. Changes in the electrical activity of the brain, but not in blood pressure and heart rate indicated central nervous system actions of LVP. However, interpretation of LVP effects in terms of memory processing seems not to be justified.     

Effect of novel specific myosin light chain kinase inhibitors on Ca2+-activated Mg2+-ATPase of chicken gizzard actomyosin.

Vascular relaxing agents such as N-(6-aminohexyl)-5-chloro-l-naphthalenesulfonamide (W-7), N²-dansyl-L-arginine-4-t-butyl-piperidine amide (No. 233), prenylamine and chlorpromazine that interact with Ca²⁺-regulated modulator protein of cyclic nucleotide phosphodiesterase inhibited Ca²⁺-dependent phosphorylation of chicken gizzard myosin light chain. Inhibition by the agents of myosin light chain phosphorylation resulted in inhibition of calcium activated, magnesium dependent adenosine triphosphatase of the gizzard actomyosin. The specificity of these agents for inhibition of light chain phosphorylation was shown by negative effect of these agents on ATPase activity of gizzard actomyosin in the phosphorylated form. Results suggest that the agents provide useful tool for the study on the Ca²⁺-sensitive regulatory mechanism of modulator-related enzyme systems.     

Clinicopathologic Factors Related to the Histological Tumor Grade of Breast Cancer in Western China: An Epidemiological Multicenter Study of 8619 Female Patients

BACKGROUND AND PURPOSE: Breast cancer is now recognized as a clinically heterogeneous disease with a wide spectrum of epidemiological and clinicopathologic features. We aimed to evaluate whether epidemiological and clinicopathologic features are associated with the histological tumor grade of breast carcinomas in Western China. METHODS: We retrospectively collected data from the Western China Clinical Cooperation Group and assessed associations between clinicopathologic factors and histological tumor grade in 8619 female breast cancer patients. Patients were divided into two groups: Group I (tumor grade I/II) and Group II (tumor grade III). Univariable analysis and multivariable logistic regression models were used to analyze the relationships between clinicopathologic factors and tumor grade. RESULTS: Patients presenting with positive axillary lymph nodes, large tumor size (>2?cm), lymphovascular invasion, hormone receptor negativity, human epidermal growth factor receptor 2 (HER-2) positivity, and triple negativity tended to have an increased risk of a high tumor grade. However, the number of pregnancies or births was inversely correlated with the risk of a high tumor grade. In addition, patients presenting with grade III tumors were more likely to receive aggressive treatment, such as adjuvant chemotherapy, anti–HER-2 therapy, and level III axillary lymph node dissection. CONCLUSIONS: Our results suggested that several clinicopathologic factors were associated with high tumor grade of breast cancer patients in Western China.     

Determination of Hepatocellular Carcinoma and Characterization of Hepatic Focal Lesions with Adaptive Multi-Exponential Intravoxel Incoherent Motion Model

PURPOSE: To distinguish hepatocellular carcinoma (HCC) from other types of hepatic lesions with the adaptive multi-exponential IVIM model. METHODS: 94 hepatic focal lesions, including 38 HCC, 16 metastasis, 12 focal nodular hyperplasia, 13 cholangiocarcinoma, and 15 hemangioma, were examined in this study. Diffusion-weighted images were acquired with 13 b values (b?=?0, 3, …, 500 s/mm²) to measure the adaptive multi-exponential IVIM parameters, namely, pure diffusion coefficient (D), diffusion fraction (f_d), pseudo-diffusion coefficient (D_i*) and perfusion-related diffusion fraction (f_i) of the ith perfusion component. Comparison of the parameters of and their diagnostic performance was determined using Mann-Whitney U test, independent-sample t test, one-way analysis of variance, Z test and receiver-operating characteristic analysis. RESULTS: D, D₁* and D₂* presented significantly difference between HCCs and other hepatic lesions, whereas f_d, f₁ and f₂ did not show statistical differences. In the differential diagnosis of HCCs from other hepatic lesions, D₂* (AUC, 0.927) provided best diagnostic performance among all parameters. Additionally, the number of exponential terms in the model was also an important indicator for distinguishing HCCs from other hepatic lesions. In the benign and malignant analysis, D gave the greatest AUC values, 0.895 or 0.853, for differentiation between malignant and benign lesions with three or two exponential terms. Most parameters were not significantly different between hypovascular and hypervascular lesions. For multiple comparisons, significant differences of D, D₁* or D₂* were found between certain lesion types. CONCLUSION: The adaptive multi-exponential IVIM model was useful and reliable to distinguish HCC from other hepatic lesions.     

Dose-Dependent Relationship Between Metformin and Colorectal Cancer Occurrence Among Patients with Type 2 Diabetes—A Nationwide Cohort Study

BACKGROUND: Increasing bodies of evidence suggest that metformin may be beneficial in the primary prevention of colorectal cancer (CRC), and a dose–response relationship has been reported. However, long-term epidemiological observations between the treatment period, cumulative dose, and intensity of metformin and CRC are rarely reported. The aim of this study was to identify the association between the effect of metformin and CRC development in a nationwide cohort study. METHODS: This nationwide population-based study examined a cohort of 1,000,000 patients randomly sampled from individuals enrolled in the Taiwan National Health Insurance system. Patients with newly diagnosed type 2 diabetes mellitus (DM) between 1997 and 2007 were enrolled. A statistical variables, including the demographic data, treatment period, cumulative dose, and intensity of metformin use, was compared between patients developing CRC and those without CRC. RESULTS: This study included 47,597 patients. The mean follow-time was 7.17 ± 3.21 years. After adjustment, metformin use was an independent protective factor against CRC development (P < .001). Although the protective ability of metformin against CRC development was reduced during long-term therapy, the risk of CRC decreased progressively with a higher cumulative dose or higher intensity of metformin use (both P < .001). CONCLUSION: This study revealed that metformin use significantly reduced the risk of CRC in a dose-dependent manner in patients with type 2 DM in the Taiwanese population. However, a gradual decline in medication adherence may reduce the protective ability of metformin against CRC development during long-term therapy.     

3D Imaging Detection of HER2 Based in the Use of Novel Affibody-Quantum Dots Probes and Ratiometric Analysis

Patients with breast cancer (BC) overexpressing HER2 (HER2+) are selected for Trastuzumab treatment, which blocks HER2 and improves cancer prognosis. However, HER2+ diagnosis, by the gold standard, immunohistochemistry, could lead to errors, associated to: a) variability in sample manipulation (thin 2D sections), b) use of subjective algorithms, and c) heterogeneity of HER2 expression within the tissue. Therefore, we explored HER2 3D detection by multiplexed imaging of Affibody-Quantum Dots conjugates (Aff-QD), ratiometric analysis (RMA_FI) and thresholding, using BC multicellular tumor spheroids (BC-MTS) (~120 μm of diameter) as 3D model of BC. HER2+, HER2– and hybrid HER2+/? BC-MTS (mimicking heterogeneous tissue) were incubated simultaneously with two Aff-QD probes (anti-HER2 and negative control (NC), respectively, (1:1)). Confocal XY sections were recorded along the Z distance, and processed by automatized RMA_FI (anti-HER2 Aff-QD/ NC). Quantifying the NC fluorescence allowed to predict the fraction of non-specific accumulation of the anti-HER2 probe within the thick sample, and resolve the specific HER2 level. HER2 was detected up to 30 μm within intact BC-MTS, however, permeabilization improved detection up to 70 μm. Specific HER2 signal was objectively quantified, and HER2 3D-density of 9.2, 48.3 and 30.8% were obtained in HER2?, HER2+ and hybrid HER2+/? permeabilized BC-MTS, respectively. Therefore, by combining the multiplexing capacity of Aff-QD probes and RMA_FI, we overcame the challenge of non-specific probe accumulation in 3D samples with minimal processing, yielding a fast, specific spatial HER2 detection and objective quantification.