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71.
新疆10种沙生植物旱生结构的解剖学研究 总被引:17,自引:1,他引:16
新疆10种沙生植物的形态解剖研究表明,它们为适应沙生环境形态结构发生变化。叶器官的形态呈三种类型:叶片退化成膜质或鳞片状,而由同化枝执行光合功能;叶片上下都具栅栏组织,表皮角质膜厚,表皮毛发达,气孔下陷,输导组织和机械组织都发达;叶片肉质化,叶肉组织不分化,贮水组织发达而输导组织不发达。轴器官中厚壁组织发达,围绕维管组织,维管组织内部也有发达的厚壁组织。根中普遍具有周皮,一些植物存在异常的维管组织,部分植物还具有粘液细胞或结晶。沙生植物形成各种旱生结构,以不同的方式适应沙生环境。 相似文献
72.
茶尺蠖人工饲料的研究 总被引:3,自引:0,他引:3
本报道饲养茶尺蠖(Ectropis obliqua hypulina Wehrli)的5种人工饲料及其饲养方法.5种人工饲料均可用于大规模饲养一代幼虫.其中62号配方可用于续代饲养,在实验室内饲养5代的结果表明。效果良好.在饲料成分的加工.配制及饲养方法等方面.较前人有相当大的改进,因而叶因子用量减少,幼虫历期缩短.用人工饲料饲养的幼虫历期为13-20天。基本接近以茶叶饲养的对照(11—18天).实验结果还表明饲料含水量.饲养方法.饲养密度和添加饲料的次数不同,对茶尺蠖的生长发育有明显的影响.初龄幼虫用平面培养基倒置饲养和高龄幼虫用片状饲料正置饲养为最佳方法. 相似文献
73.
Inhibition of the delayed-type hypersensitivity response by staphylococcal enterotoxin B-induced suppressor T cells 总被引:2,自引:0,他引:2
Staphylococcal enterotoxin B (SEB) is a member of a family of gram-positive bacterial exotoxins which act as superantigens in both mouse and man. The administration of this toxin has been shown to inhibit antibody responses in vivo. We have previously shown that SEB is a potent inducer in vitro of multiple T suppressor cell populations. The present studies show that administration of microgram quantities of this toxin result in a reduced capacity to manifest a delayed-type hypersensitivity (DTH) response. In addition, we find that the failure to generate a normal DTH response appears to be due to the generation of a T suppressor cell population following SEB administration. Adoptive transfer studies show that the suppressor cells bear the CD5+ I-J+ CD4- CD8- Thy 1+ surface phenotype. The relationship of these cells to suppressor T cell populations generated following in vitro activation by SEB is discussed. 相似文献
74.
Bernadine Hu John W. McDonald Michael V. Johnston† Faye S. Silverstein 《Journal of neurochemistry》1991,56(3):933-937
In immature rodent brain, the glutamate receptor agonist N-methyl-D-aspartate (NMDA) is a potent neurotoxin. In postnatal day (PND)-7 rats, intrastriatal injection of 25 nmol of NMDA results in extensive ipsilateral forebrain injury. In this study, we examined alterations in high-affinity [3H]glutamate uptake (HAGU) in NMDA-lesioned striatum. HAGU was assayed in synaptosomes, prepared from lesioned striatum, the corresponding contralateral striatum, or unlesioned controls. Twenty-four hours after NMDA injection (25 nmol), HAGU declined 44 +/- 8% in lesioned tissue, compared with the contralateral striatum (mean +/- SEM, n = 6 assays, p less than 0.006, paired t test). Doses of 5-25 nmol of NMDA resulted in increasing suppression of HAGU (5 nmol, n = 3; 12.5 nmol, n = 3; and 25 nmol, n = 5 assays; p less than 0.01, regression analysis). The temporal evolution of HAGU suppression was biphasic. There was an early transient suppression of HAGU (-28 +/- 4% at 1 h; p less than 0.03, analysis of variance, comparing changes at 0.5, 1, 2, and 3 h after lesioning); 1 or 5 days postinjury there was sustained loss of HAGU (at 5 days, -56 +/- 11%, n = 3, p less than 0.03, paired t test, lesioned versus contralateral striata).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
75.
Corticostatic peptides. 总被引:2,自引:0,他引:2
S Solomon J Hu Q Zhu D Belcourt H P Bennett A Bateman T Antakly 《The Journal of steroid biochemistry and molecular biology》1991,40(1-3):391-398
In the last four years corticostatic (anti-ACTH) peptides have been isolated from human, rabbit, guinea pig and rat tissues. These peptides do not act via the cAMP cell signalling system but rather via the inhibition of the binding of ACTH to its receptor most probably through direct competition with the 14-18 sequence of ACTH for receptor binding. ACTH has specific high affinity receptors on adrenal cells but rabbit corticostatin I (CSI) has high capacity, low affinity receptors which are competed for by unlabelled excess CSI but not by excess ACTH. This indicates the presence of specific CSI adrenal cell receptors. The rabbit pituitary, hypothalamus, thalamus, adrenals, lungs and placenta contain sizeable amounts of immunoassayable CSI. Immunochemical localization of CSI indicates that it is present in the large macrophages and in neutrophils in rabbit lung, in macrophages and "supporting" endothelial cells in the spleen and in the adrenals in the cells of the zona reticularis. We have also isolated and identified new peptides which contain 12 cysteines from immune cells of humans, rats and a teleost, the carp. The functions of these peptides are now being determined. This large family of peptides may have many other, yet unidentified functions but at present we can only describe a small number of these. 相似文献
76.
倭竹族花序演化的探讨 总被引:1,自引:0,他引:1
倭竹族隶于禾本科之竹亚科。本族计有10属约150余种。分布于东南亚季风带的印度、越南、中国及日本等国,我国产8属约120种,占该族全部属种的80%。其中唐竹属、短穗竹属、筇竹属、八月竹属等均为我国所特产,唐竹属1种早期引入日本栽培,倭竹属、大节竹属、方竹属、刚竹属等也主要分布于我国,只有少数种分布于其它国家,业平竹属和阴阳竹属为日本特产。 刚竹属计有70种之多,我国产50种以上,是本族中种类最多的属,其中有许多种类分布广、适应能力强,用途多、产量大。是重要的植物资源.尤其是毛竹,是我国亚热带地区的主要栽培竹种。 倭竹族花序演化的研究对于进一步认识和鉴别竹类植物.了解竹类植物的演化关系。使竹类植物的系统安排更加合理都是有益的。倭竹族的花序属于假花序.与真花序相比较属于原始类型。本族中花序轴反复分枝.具有极多小穗的短穗竹属,业平竹属等是比较原始的,大节竹属、唐竹属的花序简化、花序轴不分枝或仅有少数分枝,含小穗数很少是进化类型。 相似文献
77.
78.
本文报告尖吻蝮咬伤并心脏受累20例。经中西医结合治愈19例(95%),死亡1例(5%),并对其发病机理及治疗进行了讨论。 相似文献
79.
Shung-Tai Ho Jhi-Joung Wang Weber Ho
Oliver Yoa-Pu Hu
《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1991,570(2):339-350A rapid, sensitive, precise and accurate high-performance liquid chromatographic assay with fluorescence detection was developed for the determination of buprenorphine in human, rabbit, pig and dog plasma. It is comprised of only a one-step extraction procedure with hexane—isoamyl alcohol at pH 9.25 and reversed-phase chromatography on a μPorasil column. The recoveries of buprenorphine and nalbuphine (internal standard) were greater than 90%. Calibration graphs were linear over the concentration range 3–300 ng/ml with a coefficient of variation, both within-day and between-day, of less than 9% at any level. The limit of detection was 1.0 ng/ml of plasma based on a signal-to-noise ratio of 3. Eight other clinically used narcotics were investigated to check for potential interferences and their analytical conditions. The possible decomposed compounds of buprenorphine were also checked for the specificity of this assay. The method has been succesfully applied to the stability and pharmacokinetic studies of buprenorphine. Buprenorphine in plasma did not decompose significantly at −20°C for four weeks. Pharmacokinetic application in six rabbits and a surgical patient revealed that buprenorphine followed a linear three-compartment model with two distribution phases. The two distribution and elimination half-lives and the clearance of buprenorphine were 1.32, 24.8 and 230 min and 224 ml/min in human plasma, and 0.94, 12.5 and 232 min and 30 ml/min in rabbit plasma. 相似文献
80.
B Halliwell M L Hu S Louie T R Duvall B K Tarkington P Motchnik C E Cross 《FEBS letters》1992,313(1):62-66
Nitrogen dioxide (NO2.) is often present in inhaled air and may be generated in vivo from nitric oxide. Exposure of human blood plasma to NO2. caused rapid losses of ascorbic acid, uric acid and protein thiol groups, as well as lipid peroxidation and depletions of alpha-tocopherol, bilirubin and ubiquinol-10. No increase in protein carbonyls was detected. Supplementation of plasma with ascorbate decreased the rates of lipid peroxidation, alpha-tocopherol depletion and loss of uric acid. Uric acid supplementation decreased rates of lipid peroxidation but not the loss of alpha-tocopherol. We conclude that ascorbic acid, protein -SH groups, uric acid and alpha-tocopherol may be important agents protecting against NO2. in vivo. If these antioxidants are depleted, peroxidation of lipids occurs and might contribute to the toxicity of NO2.. 相似文献