Baculovirus-mediated expression of Plasmodium falciparum erythrocyte binding antigen 175 polypeptides and their recognition by human antibodies

The erythrocyte binding antigen EBA-175 is a 175-kDa Plasmodium falciparum protein which mediates merozoite invasion of erythrocytes in a sialic acid-dependent manner. The purpose of this study was to produce recombinant EBA-175 polypeptide domains which have previously been identified as being involved in the interaction of EBA-175 with erythrocytes and to determine whether these polypeptides are recognized by malaria-specific antibodies. The eba-175 gene was cloned by PCR from genomic DNA isolated from the 3D7 strain of P. falciparum. The predicted protein sequence was highly conserved with that predicted from the published eba-175 gene sequences from the Camp and FCR-3 strains of P. falciparum and contained the F segment divergent region. Purified recombinant EBA-175 polypeptide fragments, expressed as glutathione S-transferase fusion proteins in insect cells by using the baculovirus system, were recognized by antibodies present in serum from a drug-cured, malaria-immune Aotus nancymai monkey. The fusion proteins were also recognized by antibodies present in sera from individuals residing in areas where malaria is endemic. In both cases the antibodies specifically recognized the EBA-175 polypeptide portion of the fusion proteins. Antibodies raised in rabbits immunized with the recombinant fusion proteins recognized parasite proteins present in schizont-infected erythrocytes. Our results suggest that these regions of the EBA-175 protein are targets for the immune response against malaria and support their further study as possible vaccine components.     

The effect of arachidonic acid on junctional conductance in isolated murine hepatocytes

Arachidonic acid (AA) is known to inhibit intercellular conductance in normal and tumour cells. We showed that junctional conductance (Gj) in isolated murine hepatocytes was relatively tolerant to the uncoupling effect of AA. Extracellular application of 100 microM AA decreased Gj in less than 50% of hepatocytes, and the effect was much slower in other cells (10-15 min vs. 2-5 min, respectively). The uncoupling effect of AA did not depend on the intracellular [Ca2+] within the pCa(i) range 7.7-9.0. Similar results were obtained using the pipette-filling solutions with low (1 mM) and high (10 mM) concentrations of a Ca-chelating agent (EGTA). To verify whether the resistance of the hepatocyte Gj to AA may result from the "wash-out" of the intracellular intermediates during the intracellular dialysis, Gj was measured 10-45 min after the preincubation of hepatocytes with AA. After such a treatment, in 62% of cell pairs the Gj values recorded did not differ from the control. Extracellular or intracellular acidification (pHo 6.0 or pHi 5.0-6.0) did not markedly affect the AA action. However, in some cases AA induced the recovery of Gj blocked after intracellular acidification, the phenomenon suggesting the activation of the H+ transport in the presence of AA. Possible mechanisms of the observed resistance of junctional conductance of mouse hepatocytes in primary culture are discussed.     

双相不锈钢在含硝酸体系中的优选腐蚀行为研究

研究了双相不锈钢在氧化性的HNO3 HCl、HNO3 NaCl、HNO3 FeCl3 3种体系中两相的腐蚀差异．通过动电位极化实验，用SEM和EDS对表面形貌进行观测和两相的鉴别，发现奥氏体相是优先腐蚀的相，在HNO3 HCl和HNO3 NaCl中随着CL^-浓度的增加，两相的优选腐蚀更加明显。但在HNO3 ReCl3中。低浓度的FeCl3会掩盖两相的优选腐蚀，而高浓度的FeCl3不存在这种反常行为．     

TiNi形状记忆合金电阻钎焊接头微观组织分析

利用自行改制的数控交流电阻焊机，采用CuNi薄带钎料，配合改进型钎剂实现了TiNi形状记忆合金电阻钎焊连接。借助于光学显微镜、SEM及EDX对钎缝的组织进行了分析。结果表明，试验采用的电阻钎焊工艺对母材的热影响极小，接头中没有明显的热影响区；在钎缝中存在的Ti，Ni4化合物相是TiNi合金产生双程及全程形状记忆效应的主要因素。     

Column-switching high-performance liquid chromatographic assay for determination of apigenin and acacetin in human urine with ultraviolet absorbance detection

Postweaning social isolation can influence the sensitivity of rats to several effects of drugs of abuse. The present study investigated the influence of postweaning housing conditions on the sensitivity of rats to the aversive effects of a number of psychoactive agents using a conditioned taste aversion (CTA) test procedure. Development of a CTA was assessed by pairing administration of the drug with the consumption of a 0.05% (weight/volume) saccharin solution in water-deprived (18 h) rats in a 20 min drinking period. Saccharin consumption was then measured in 20 min test sessions over the next 4 consecutive days. Consumption of saccharin solution was significantly reduced in both isolated and enriched rats following administration of d-amphetamine (2 mg/kg), cocaine (30 mg/kg), morphine (10 mg/kg), nicotine (1.0 mg/kg), caffeine (20 mg/kg), alcohol (1.5 g/kg), and LiCl (0.15 M, 4 ml/kg). There was no significant effect of housing conditions on the CTA induced by cocaine, nicotine, alcohol, or LiCl; however, isolation-reared rats were found to be less sensitive to the aversive effects of d-amphetamine, morphine, and caffeine in this paradigm. These results suggest that rearing rats in social isolation induces an attenuation in sensitivity to the aversive effects of some psychoactive agents.     

Interferon alpha with ribavirin for the treatment of chronic hepatitis C in non-responders or relapsers to interferon monotherapy

The ability of different serotypes of group B streptococci (GBS) to induce septic arthritis in mice was compared. Types II, III, IV, V, VI and VII GBS were investigated. A highly capsulate strain of type III GBS, COH1, and its mutants, COH1-11 (lacking capsular sialic acid) and COH1-13 (non-capsulate), obtained by transposon insertional mutagenesis, were used to assess the role of type-specific polysaccharide on the induction of arthritis. At an intravenous dose of 10(7) cfu/mouse, reference strains of types II, III, IV, VI and VII and type III strain COH1 induced arthritis with an incidence ranging from 70 to 90%. For type V and strain COH1-11, 10(8) cfu/mouse was required to obtain a 50% incidence of arthritis; lesions were not evident with strain COH1-13. The presence of the capsule played a major role in the induction of GBS septic arthritis. The presence and amount of sialic acid in capsular polysaccharide influenced the incidence of articular lesions. The bacterial dose affected the manifestations of arthritis; the less virulent strains of GBS also induced articular lesions when an adequate number of micro-organisms reached the joints.     

MIBI-scintigraphy. A simple and reliable method for localization of pathological parathyroid glands

99Tcm-sestamibi scintigraphy was used to localise enlarged parathyroid glands in 25 patients with primary hyperparathyroidism previously operated in the neck, 20 of whom had recurrent disease and five had previously undergone surgery for thyroid disorders. Of the 18 patients for whom positive scans were obtained, nine were operated on the scan findings being confirmed. Crucial information was provided in two cases of intrathyroidal and one case of intramediastinal localisation of the pathological gland were not operated on as the hypercalcaemia was only marginal or the symptoms were vague. Though preoperative localisation of pathological parathyroid glands is a prerequisite for neck exploration in patients with persistent or recurrent hypercalcaemia due to primary (or secondary) hyperparathyroidism, the procedure is not cost-effective before the initial operation.     

An outpatient unit for early pregnancy. Establishment and effects on the pattern of hospital admissions

We report on a 67-year-old woman with acute lymphoblastic leukemia (ALL) who was supposed to have a variant Philadelphia (Ph) translocation identified by conventional cytogenetic techniques. Fluorescence in situ hybridization (FISH) analysis demonstrated the presence of an amplification of BCR-ABL rearrangement at locus 22q11. This is the first observation, to our knowledge, of a duplicated BCR-ABL chimeric gene within the derived chromosome 22 in ALL. Our observation supports the possibility of detecting a variant Ph chromosome at the single-cell level by FISH analysis.     

可拓评价方法的改进及其应用研究

将可拓工程方法与高层建筑中对火灾风险有影响的因子相结合,建立了高层建筑火灾风险评估的可拓评价模型。首先在该模型中对原可拓评价方法进行了修正,提出了最大贴近度法与最大对比度法。其次在原可拓评价方法的基础上首次建立了多级可拓评价模型,解决了用可拓评价方法进行多因素评价的问题。最后对高层建筑火灾风险评估进行了实例分析,根据实际情况采用可拓方法选取权重,并与文献中已有的权重进行比较,结果表明在不同权重下的评价结果基本一致.