An experimental study of immunity to hepatitis A in monkeys

In this work the experimental model of hepatitis A on monkeys, adequate to human hepatitis A, was used. Ten monkeys (6 Macaca mulatta and 4 Cercopithecus aethiops) were reinfected with different doses of hepatitis A virus (HAV) a year after recovery from spontaneous and experimental hepatitis A. The monkeys were completely resistant to the inoculation of the virus in moderate doses (10(3) ID50). The inoculation of HAV in large doses (10(4)-10(5) ID50) induced a mild form of this infection in the animals with a transient rise in the level of serum alanin aminotransferase and HAV shedding in feces, but in the absence of morphological changes in the liver. It should be specially pointed out that after the reinfection of monkeys virus shedding in feces was observed, which may be of great epidemiological importance. After reinfection the absence of IgM and a pronounced rise in the titers of IgC antibodies were observed.     

Characterization of three novel monoclonal antibodies against hepatitis C virus core protein

Three novel monoclonal antibodies (MAbs) were established against a recombinant hepatitis C virus (HCV) core protein derived from cloned genotype 1b HCV cDNA. MAbs C7-50 and C8-59 recognize a conserved linear epitope represented by amino acid residues 21 to 40 of the nucleocapsid protein. MAb C8-48 is directed against a strain-specific conformational epitope located within the first 82 amino acids. A sensitive two-site MAb-based immunoradiometric assay was established using antibodies directed against distinct epitopes on the nucleocapsid protein. Processed 21 kDa core protein was detected by immunoblotting in human hepatocellular carcinoma cell lines and primary adult rat hepatocytes transfected with a cytomegalovirus promoter-driven expression construct. Immunofluorescence microscopy studies revealed a granular and vesicular cytoplasmic staining pattern. MAb C7-50 was used successfully to detect HCV core antigen in chronically infected chimpanzee liver tissue. These MAbs represent important reagents for the study of HCV biology and for the development of immunodiagnostic assays.     

关于离子源供气气压稳定性的探讨

一、前言随着离子源应用范围的扩展,对其工作稳定性的要求也越来越高。为改善离子源的工作特性,必须维持放电参数的稳定。放电参数主要取决于放电电流、磁场和放电室气压。其中,气压的稳定性对放电等离子体密度、引出离子束流、质子比及离子电荷数的影响最为明显。由图1,2,3,4可见,在最佳气压下,离子密度、质子比、引出离子束流出现峰值,最佳值两侧则明显下降。通常,离子源都希望选在最佳气压下工作。因此,保持气压的稳定性十分重要。对于直流工作状态的离子源尤其如此。     

Metabolism and excretion of dimethoate following ingestion of overtolerance peas and a bolus dose

Data to guide an exposure assessment were obtained by giving sugar peas containing overtolerance dimethoate residues (17 ppm; 8% oxon) and a bolus dose of dimethoate to a healthy adult male. The dimethoate tolerance on peas was and remains 2 ppm. Serial total urine samples were collected and analysed for dimethoate and its oxon, dimethylphosphate, dimethylphosphorothioate (DMTP) and dimethylphosphorodithioate. The dose of dimethoate administered was approx. 0.1 mg/kg body weight and produced no symptoms of toxicity. Dimethylphosphates appeared in the urine within 2 hr. The major metabolite (about 60%) was DMTP. Only traces (< 0.5%) of dimethoate and oxon were recovered from urine. Acetylcholinesterase inhibition was not observed although urinary metabolites were prominent, indicating that they are better indicators of acute exposure than cholinesterase inhibition. The results obtained using a bolus dose were virtually identical to those from the trial with overtolerance peas, and indicated that dimethoate is readily absorbed and its urinary metabolites are readily eliminated following exposures to low doses (0.1 mg/kg body weight).     

Phase II trial of paclitaxel by 24-hour continuous infusion for relapsed non-Hodgkin's lymphomas: Southwest Oncology Group trial 9246

PURPOSE: The Southwest Oncology Group (SWOG) recently conducted a multiinstitutional phase II trial to determine the complete response (CR) and partial response (PR) rates, toxicities, and progression-free and overall survivals of patients with relapsed non-Hodgkin's lymphomas (NHLs) treated with a 24-hour continuous infusion of paclitaxel at a dose of 175 mg/m2. PATIENTS AND METHODS: Sixty-six patients with relapsed NHL who had received minimal prior therapy (one prior chemotherapy regimen for intermediate- to high-grade NHL [44 patients] or one or two prior regimens for low-grade NHL [22 patients]) were premedicated with dexamethasone, diphenhydramine, and cimetidine and then treated with continuous intravenous infusion paclitaxel over 24 hours every 21 days. RESULTS: Eleven of 66 patients (17%) achieved rigorously documented objective remissions, including two CRs (3%) and nine PRs (14%). In addition, another five patients (8%) achieved apparent PRs on a single computed tomographic (CT) scan. Responses were brief, lasting a median of 3 months (5 months for indolent lymphomas and 3 months for intermediate- to high-grade lymphomas). Grade 4 or 5 granulocytopenia was the only common serious toxicity, and occurred in 42 of 66 patients (64%). CONCLUSION: Paclitaxel is generally well tolerated when given as a continuous infusion of 175 mg/m2 over 24 hours, despite predictable granulocytopenia. However, single-agent paclitaxel has modest clinical efficacy compared with other available treatments for relapsed NHL.     

Oxidative cross-linking of plasma membrane arabinogalactan proteins

STUDY OBJECTIVE: Endotoxin is a powerful trigger of systemic inflammation. Since cardiac surgery exposes patients to endotoxemia, this study was set up to define the relationship between preoperative endogenous endotoxin immune status, gut perfusion, and outcome following cardiac valve replacement surgery. DESIGN: Observational study. SETTING: University hospital. PATIENTS: Fifty-nine consecutive patients undergoing cardiac valve replacement. MEASUREMENTS AND MAIN RESULTS: Blood was assayed for IgG and IgM endotoxin core antibody (EndoCAb) levels preoperatively, immediately postoperatively, and at 4 h and 24 h postoperatively. Intraoperative gut mucosal perfusion was assessed using gastric tonometry. Complications were assessed for groups above and below the median EndoCAb value of a healthy population (100 median units micro/mL). Of the 59 patients, 12 developed at least one of a set of predefined complications. Of these 12, all had preoperative levels of IgM EndoCAb below 100 MU/mL (p<0.025). Eleven had IgG EndoCAb levels below 100 MU/mL (0.05相似文献   

Biological effects in natural populations of small rodents in radiation-polluted territories. Dynamics of chromosome aberration frequency in a number of generations of European bank vole (Clethrionomys glareolus, Schreber)

The dynamics of chromosome aberration frequency in bone marrow cells of many generations (14) of bank vole living in the radioactive trace of the Chernobyl catastrophe (1986-1992) has been analysed. The study revealed that the chromosome aberration frequency in voles in the areas with radio-contamination density 220 and 1526 kBq/m2 (for 137Cs) significantly exceeds the control level 3-7 times over the whole period under investigation. The dynamics of the frequency of structural chromosome injuries from 1986 to 1991-1992 is characterised by the tendency to increase in all populations inhabiting the areas with various radio-contamination density (8-1526 kBq/m2).