用于杀虫剂评价的水池中无脊椎动物的群落结构及其种群动态

实验水池是评价杀虫剂效应和安全生的重要场所，水池中无脊椎动物群落结构和种群动态是评价杀虫剂的基础资料和考核指标，本文报告１９９２年至１９９３年在美国佛罗里达中部地区对应用于杀虫剂评价的实验水池中昆虫与其它无脊椎动物群落结构及其优势种的种群动态研究结果，用羽化诱捕、勺舀、网拉及挖取底物法，从实验水池中共采到昆虫与其它无脊椎动物５０余类，其中，羽化诱捕到的昆虫中摇蚊占９３．９％，蜉蝣目昆虫占４．６％，     

Emotional abuse, self-blame, and self-silencing in women with irritable bowel syndrome

OBJECTIVE: The purpose of this study was to investigate the presence of emotional abuse and two psychosocial constructs (self-blame and self-silencing) in a sample of women diagnosed with irritable bowel syndrome (IBS) relative to a comparison sample of women diagnosed with inflammatory bowel disease (IBD). METHODS: Women diagnosed with IBS (N = 25) were compared with women diagnosed with IBD (N = 25) on measures of history of abuse, self-blame, and self-silencing. RESULTS: It was found that women in the IBS sample scored significantly higher on emotional abuse, self-blame, and self-silencing than did women in the IBD sample. These three variables were also found to be significantly intercorrelated in both the IBS and IBD samples. Finally, emotional abuse was significantly higher in IBS patients than in IBD patients beyond the differences accounted for by physical and/or sexual abuse history. CONCLUSIONS: These findings empirically demonstrate an association between IBS and emotional abuse, as well as a possible connection with psychosocial variables, that may mediate the connection between emotional abuse and functional bowel symptoms. We suggest that these variables be further evaluated in the context of clinically relevant research on IBS.     

The effect of prostaglandin synthesis inhibition on motility of the sheep ureter

To determine the effect of prostaglandin-synthesis inhibition on ureteral motility, isolated rings of sheep ureters were suspended for recording isometric tension in organ baths filled with Krebs-Henseleit solution. The non-steroidal anti-inflammatory drugs (NSAIDs) indomethacin and diclofenac sodium (10(-5) M) inhibited rhythmic ureteral motility by reducing frequency, amplitude and finally stopping contractions. Prostaglandin F2 alpha, 6-keto-prostaglandin F1 alpha and thromboxane B2 were determined by radioimmunoassay in the bathing solution before and after addition of NSAIDs. Peak contractile activity at 100 min of suspension was associated with increased concentration of all three prostanoids and 50 min after addition of indomethacin and diclofenac sodium when rhythmic contractions stopped, concentration dropped to low levels. The concentration of prostaglandins released into the organ bath were not quantitatively related to the frequency of contractions and therefore do not seem to affect pacemaker activity within ureteral smooth muscle but rather intercellular recruitment of myo-genically active fibres. These findings indicate that prostaglandins play a role in the motor control of the ureter, and that non-steroidal anti-inflammatory drugs exert an inhibitory action.     

Eucaryotic Expression of the Nucleocapsid Protein Gene of Porcine Circovirus Type 2 and Use of the Protein in an Indirect Immunofluorescence Assay for Serological Diagnosis of Postweaning Multisystemic Wasting Syndrome in Pigs

The purpose of this study was to develop a sensitive, rapid, and inexpensive immunofluorescence assay (IFA) using a recombinant porcine circovirus type 2 (PCV2) nucleocapsid protein for the serological detection of PCV2-specific antibodies in pig sera. The viral nucleocapsid protein encoded by the PCV2 ORF2 gene has recently been identified as the most immunoreactive viral protein that carries type-specific antigenic determinants. The ORF2 sequence of the IAF-2897 strain of PCV2 has been cloned into a pCEP5 eucaryotic expression vector under the control of the cytomegalovirus promoter, downstream of a polyhistidine sequence tag. The recombinant plasmid was used in transfection experiments with human epithelial kidney 293 cells that were further tested, and positive expression of the viral nucleocapsid protein was confirmed by IFA and Western blotting. Strong, specific fluorescence was observed in the nuclei of transfected cells. Test specificity to PCV2 was verified with several related infectious agents. Sensitivity was compared to that of standard IFA using PCV2-infected cells by evaluating the reactivities of 44 field serum samples from pigs on farms with a porcine population suffering from postweaning multisystemic wasting syndrome. The recombinant nucleocapsid-based test was able to detect 15 more positive-testing pigs than the PCV2-based IFA. Therefore, the relative sensitivity of the latter test was estimated at only 57.1% compared to that of the recombinant nucleocapsid-based test. The recombinant fusion protein has been purified by affinity chromatography and is being used to develop further sensitive serological tests.     

Foscarnet salvage therapy efficacy is associated with the presence of thymidine-associated mutations (TAMs) in HIV-infected patients

BACKGROUND: Salvage therapy based on foscarnet plus a thymidine analog is effective in patients with advanced-stage HIV disease and viruses harbouring multiple drug-resistance mutations. OBJECTIVE: To identify viral genetic determinants associated with the virological efficacy of foscarnet salvage therapy. STUDY DESIGN: Thirteen patients received foscarnet at a fixed dose of 80mg/kg twice daily for 14 days, in combination with zidovudine or stavudine. RESULTS: The baseline median HIV viral load and CD4 cell count were 5.10log(10)copies/ml and 23cells/mm(3), respectively. Following foscarnet therapy, viral load fell by a median of 1.84log(10)copies/ml (range: -0.29 to -2.82), and by at least 1log(10)copies/ml in 11 patients, all of whom harboured viruses with at least three thymidine-associated mutations (TAMs). The two patients with smaller declines in viral load (<0.50log(10)copies/ml) harboured viruses with only one or zero TAMs. CONCLUSIONS: These findings corroborate, in vivo, the impact of TAMs on HIV susceptibility to foscarnet. The virological response to foscarnet salvage therapy in multiclass-experienced patients may thus differ according to the number of TAMs.     

Antibiotic prophylaxis influences cardiovascular stability in complicated surgery

Objective:Antibiotic prophylaxis is used in many surgical procedures but there are frequent cardiovascular instabilities following antibiotics in perioperative period. A clinic modelling randomised trial (CMRT) in pigs was developed to compare the effects of 2 commonly used antibiotic combinations on cardiovascular stability during major surgery. Materials and methods:Thirty pigs (both sexes) were randomised into 3 groups, receiving either saline (placebo), co-amoxiclav or cefuroxime/metronidazole in clinically relevant doses as antibiotic prophylaxis. A laparotomy was performed and the abdomen remained open. Surgical complications were simulated by removing one third of the blood volume. For fluid resuscitation, 500 ml hetastarch (HAES^TM) were infused rapidly (therapy of complication) and polymyxin B (15 mg/kg bodyweight) was applied for induction of histamine release reactions (complication of therapy). The main end points were histamine release reactions, these were classified by 2 blinded investigators. Results:Neither cardiovascular changes nor histamine release reactions were detected immediately after the administration of antibiotics or placebo alone. Plasma histamine concentrations increased after bleeding in the co-amoxiclav group (p < 0.05). After fluid resuscitation and induction of anaphylactoid reactions, the median histamine release and cardiovascular changes were not significantly different between the groups. However, the incidence of typical histamine release related reactions differed significantly between the groups: 8/10 for the controls, 6/10 in the co-amoxiclav and 2/10 in the cefuroxime/metronidazole group (p < 0.05). Conclusions:The stability and reproducibility of this model clearly demonstrated the concept of a ‘clinic modelling randomised trial’ as a useful tool. Antibiotic prophylaxis influences the organism’s capability to cope with intraoperative bleeding and fluid resuscitation problems. Indeed antibiotic prophylaxis may be beneficial. These effects of antibiotics could only be demonstrated in complex surgical models. Thus new antibiotics should be investigated in complex animal models prior to prospective randomised clinical trials or usage in clinical practice.     

Analysis of the mechanism of immunodepression following heterologous antigenic stimulation during concurrent infection with Nematospiroides dubius.

The suppression of immune responsiveness to heterologous antigenic stimulation during concurrent infection with Nematospiroides dubius was reproduced using soluble antigens derived from adult parasites. Immunosuppression appeared to be selective in that the administration of equivalent quantities of an irrelevant heterogeneous antigen had no immunosuppressive effect, and suppression was transferable using spleen cells from parasite antigen-treated donors. The differential immunomodulatory activity of parasite antigens from a variety of nematode species suggested that a correlation might exist between suppressor activity and chronicity of infection. A role for suppressor T cell activity in the infected host was implicated by the restorative effect of 2'deoxyguanosine treatment on the immune response, and non-specific suppressor cell activity was detected in splenocyte populations from infected mice. It is suggested that a parasite-induced defect in antigen processing led to the induction of suppressor cell activity in the infected host and that this may be one mechanism of parasite survival. The relevance of these observations to vaccination against chronic gastrointestinal nematode infections is discussed.     

Influence of a self-etching primer on compound nerve action potentials

The aim of this study was to evaluate the effect of self-etching primers on nerve conductance. A self-etching primer (One Up Bond F) which combines etching and bonding in one step, and a fifth-generation bonding agent (Prime&Bond NT ) were tested. Isolated rat sciatic nerves were placed between two platinum electrodes in a bath containing Tyrode solution. The bonding agents were brought into contact with the nerves and the evoked compound action potentials (CAP) were recorded before and after contact with the materials. One Up Bond F caused total inhibition of the CAP within an average time of 7 min. All CAPs in this group were blocked irreversibly. As with Prime&Bond NT, the reduction in CAP was 45.9% after an application time of 15 min, after which readings were terminated. Recovery of the CAP in this group were maintained after rinsing with fresh tyrode solution. One Up Bond F elicited faster blocking of nerve conductance under the conditions of this model. In the context of dentin desensitization with bonding agents, the self-etching primer may be more effective, clinically.