流感病毒M2基因变异与盐酸金刚烷胺耐药性的关系

盐酸金刚烷胺是治疗流感的常用药物,但流感病毒极易产生耐药性并发生变异.本文仅就使用盐酸金刚烷胺后流感病毒M2基因的变异情况作一综述.     

HPLC法测定盐酸氨丙啉的含量及对杂质2-甲基吡啶进行检查

采用高效液相色谱法测定盐酸氨丙啉的含量及对杂质2-甲基吡啶进行检查.用Waters XTerraTM RP C18色谱柱,以乙腈-甲醇-庚烷磺酸钠溶液(将12 g的1-庚烷磺酸钠溶于1000 mL水中,加24mL冰醋酸,6 mL的三乙胺制得)(5:35:60)为流动相,用紫外检测器于254nm处检测,柱温30℃,流速1.0 mL/min.在该条件下盐酸氨丙啉和2-甲基吡啶的分离度很好,盐酸氨丙啉浓度在0.05～0.50 mg/mL范围内,其色谱峰面积与浓度呈良好的线性关系,回归方程为y=3.07×107x-3.90×104,r=0.999 9,RSD=0.76%.该法适用于盐酸氨丙啉原料药的质量控制.     

复方磷霉素钙水溶性粉处方优化实验

为了优选磷霉素钙复方制剂,采用体外药物最小抑菌浓度测定法,测定了磷霉素钙与甲氧啶(TMP)、丁胺卡那霉素、恩诺沙星、庆大霉素、头孢噻肟钠、多西环素、氟甲砜霉素联合使用对大肠杆菌作用的协同指数.结果表明磷霉素钙与TMP的协同关系最好,协同指数为0.281,制剂中磷霉素钙与TMP的含量分别为5%和1%为最佳.     

Pain management in horses and farm animals

Objective: This review discusses the different analgesic drugs and routes of administration used in large animals for acute pain management. General guidelines and doses are given to assist in choosing techniques that provide effective analgesia. Etiology: Noxious stimuli are perceived, recognized, and localized by specialized sensory systems located at spinal and supraspinal levels. Diagnosis: Localizing the source of the noxious stimulus as well as understanding the behavioral aspects and physiological changes that result from such insult is important to adequately diagnose and treat pain. Pain assessment is far from being definite and objective; not only are there species differences, but also individual variation. In addition, the behavioral and physiological manifestations vary with the acute or chronic nature of pain. Therapy: Pain management should include (1) selecting drugs that better control the type of pain elicited by the insult; (2) selecting techniques of analgesic drug administration that act on pathways or anatomical locations where the nociceptive information is being processed or originating from; (3) combining analgesic drugs that act on different pain pathways; and (4) provide the best possible comfort for the animal. Prognosis: Providing pain relief improves the animal's well being and outcome; however, interpreting and diagnosing pain remains difficult. Continuing research in pain management will contribute to the evaluation of the pathophysiology of pain, pain assessment, and newer analgesic drugs and techniques.     

Phylogenetic Analysis of Sugarcane Rusts Based on Sequences of ITS, 5.8 S rDNA and D1/D2 Regions of LSU rDNA

Phylogenetic analysis of sugarcane rusts based on sequences of ITS and the 5.8 S rDNA revealed two highly divergent ITS groups among isolates of Puccinia sp. sensu Muta, 1987 and P. kuehnii specimens. Although there is sufficient divergence (exceeding normal intraspecific variation) between the ITS regions of the two groups to support separation into different species, unusually high homology of the ITS group I sequences with those of members of Cronartium and identical sequences of the D1/D2 regions of the LSU rDNA for all the isolates of “Puccinia sp.” and P. kuehnii that otherwise exhibited different ITS sequences, suggest that the two highly divergent sequences may have resulted from abnormal genetic events leading to non-orthologous, intraspeciflc polymorphisms. The other sugarcane rust, P. melanocephala and the grass rusts, P. miscanthi and P. rufipes, were separated from “Puccinia sp.” and P. kuehnii and from each other in D1/D2 region analyses, indicating that D1/D2 region sequences may more correctly reflect phylogenetic relationships in these rusts than do the ITS regions. Further studies to examine differences in patho-genicity or finer morphological features within P. kuehnii that may be correlated with the high divergence in ITS sequences and experiments to determine if these two sequence types represent intraspeciflc polymorphism are necessary. Received 11 October 2000/ Accepted in revised form 24 November 2000     

Cutting weeds with a CO2 laser

Stems of Chenopodium album . and Sinapis arvensis . and leaves of Lolium perenne . were cut with a CO₂ laser or with a pair of scissors. Treatments were carried out on greenhouse-grown pot plants at three different growth stages and at two heights. Plant dry matter was measured 2 to 5 weeks after treatment. The relationship between dry weight and laser energy was analysed using a non-linear dose–response regression model. The regression parameters differed significantly between the weed species. At all growth stages and heights S. arvensis was more difficult to cut with a CO₂ laser than C. album . When stems were cut below the meristems, 0.9 and 2.3 J mm⁻¹ of CO₂ laser energy dose was sufficient to reduce by 90% the biomass of C. album and S. arvensis respectively. Regrowth appeared when dicotyledonous plant stems were cut above meristems, indicating that it is important to cut close to the soil surface to obtain a significant effect. When cutting L. perenne plants with 2-true leaves at a height of 2 cm from the soil surface with a laser, the biomass decreased significantly compared with plants cut by scissors, indicating a delay in regrowth. This delay was not observed for the dicotyledonous plants nor for the other growth stages of L. perenne .     

中国土地沙漠化对大气CO_2含量的影响

本文根据我国不同地区沙漠化类型的面积、土壤有机碳的含量及沙漠化的正逆转速率，计算了我国沙漠化土地中有机碳的变动。结果表明，我国沙漠化土地０－５０ｃｍ土层中有机碳的，总贮量为７５３．１４３Ｍｔ，近４０年来因土地沙漠化而释放到大气中的ＣＯ２，总量达１７３．２８６Ｍｔ，而逆转过程中固定的ＣＯ２量为５９．１２４Ｍｔ碳，所以，近４０年来我国沙漠化土地净释放到大气中的ＣＯ２量为１２４．４７５Ｍｔ碳，占全球温带和寒带土地每年释放ＣＯ２量１３３Ｍｔ碳的９３．５％。     

Biological control of cucumber powdery mildew with Tilletiopsis minor under greenhouse conditions

In growth cabinet and greenhouse experiments the efficacy ofTilletiopsis minor in controlling cucumber powdery mildew decreased as humidity was lowered. This effect could be counteracted by formulation of the mycoparasite with lipophilic substances, like Hora Oleo 11E and lipids from milk. These formulations, without the mycoparasite, were also found to be deleterious to powdery mildew development. In the long run, however, formulations withT. minor gave better biological control of cucumber powdery mildew than formulations alone.     

The induction of 1,3-β-glucanases and other enzymes in groundnut leaves infected with Cercospora arachidicola

Infection of groundnut leaves with the early leaf spot pathogen Cercospora arachidicola leads to a marked increase in extracellular 1,3-β-glucanase activity, limited to the infected tissue. Three isoforms of low molecular weight and extreme pI values, typical of pathogenesis-related proteins, were induced. These β-glucanases, when acting together, were capable of degrading the pathogen cell wall in vitro. Glucanases from homogenates of infected leaf tissue were partially purified by ion-exchange chromatography to give enzymes with molecular weights of 35, 32 and 20 kDa and pI values of 3·8, 3·6 and > 9, respectively. They were electrophoretically identical to the β-glucanases found in the intercellular washing fluid. Treatment of groundnut plants with 200 μM mercuric chloride induced the accumulation of identical extracellular β-glucanases. During the course of the infection an increase in peroxidase activity was also observed, but chitinase activity remained more or less constant.