Comparison of HLA-DR1-restricted T cell response induced in HLA-DR1 transgenic mice deficient for murine MHC class II and HLA-DR1 transgenic mice expressing endogenous murine MHC class II molecules

Transgenic mice expressing human HLA class II molecules provide a useful model for identifying HLA-restricted CD4+ epitopes. However, the influence of endogenous murine H-2-restricted T cell responses on HLA-restricted responses is not known. In the present study, we show that HLA-DR1 transgenic mice deficient for H-2 class II expression (HLA-DR1+/+/IAbeta0/0) exhibit an equivalent expression level of the transgene HLA-DR1 and a similar diversity in the TCR repertoire, but a slightly different number of CD4+ peripheral T cells, when compared to HLA-DR1 transgenic mice in which H-2 class II molecules were retained (HLA-DR1+/+/IAbeta+/+). More importantly, a strong antigen-specific HLA-DR1-restricted response was observed in nearly all HLA-DR1+/+/IAbeta0/0 mice immunized with HBV envelope protein (HBs) or capsid protein (HBc), whereas weak HBs- or HBc-specific HLA-DR1-restricted responses were detected in half of the immunized HLA-DR1+/+/IAbeta+/+ mice. Conversely, strong HBs- or HBc-specific H-2-restricted T cell responses were detected in HLA-DR1+/+/IAbeta+/+ mice but not in HLA-DR1+/+/IAbeta0/0 mice. Our results indicate that the coexpression of endogenous H-2 class II molecules reduces the intensity of HLA-DR1-restricted antigen-specific responses in transgenic mice, by favoring murine over human MHC recognition and education. Thus, HLA-DR1+/+/IAbeta0/0 mice represent a better model for identifying and characterizing HLA-DR1-restricted epitopes relevant for human disease.     

Experimental infection of pigs with aTaenia species from Korea: parasitological and serological aspects

Belgian Landrace piglets were experimentally infected with eggs of aTaenia sp. of Korean origin. At autopsy, metacestodes were present only in the livers. The proportion of degenerated metacestodes increased from 12%–39% at 5 weeks to 94%–100% at 10 weeks after infection. A sandwich enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies raised against the excretory-secretory products ofT. saginata metacestodes detected circulating antigen in the sera of the pigs at 1 week post-infection. A good correlation was found between the presence of viable metacestodes and the detection of circulating antigen; the latter disappeared as the metacestodes died off. However, the antibodies were detected only after 3 weeks of infection and onwards until the necropsy of the pigs.Financial support for this study was provided by the Institute for Scientific Research in Industries and Agriculture (IWONL, Brussels)     

Loss of heterozygosity on the X chromosome in human breast cancer

The analysis of loss of heterozygosity (LOH) in tumours can be a powerful tool for mapping the sites of tumour suppressor genes in the human genome. A panel of breast cancer patients was assembled as pairs of tumour and lymphocyte DNA samples and LOH studies carried out by Southern hybridisation with polymorphic loci mapping to the X chromosome with appropriate controls. Deletion mapping revealed a high frequency of small regionalised deletions, defining at least three independent regions, one of which is particularly well mapped to a 500 kb stretch of DNA in the distal portion of the pseudoautosomal region of Xp. A second region has been identified within the pseudoautosomal region close to the pseudoautosomal boundary, and there is a third discrete site of loss on distal Xq. Perturbations of sequences at these regions represent independent events in a number of patients. This study represents the first detailed analysis of LOH on the X chromosome in human breast tumours, the results of which indicate that at least three regions of this chromosome are involved in the disease. © 1995 Wiley-Liss, Inc.     

Symptomatic peripheral arterial disease: the value of a validated questionnaire and a clinical decision rule

BACKGROUND: If a validated questionnaire, when applied to patients reporting with symptoms of intermittent claudication, could adequately discriminate between those with and without peripheral arterial disease, GPs could avoid the diagnostic measurement of the ankle brachial index. AIM: To investigate the Edinburgh Claudication Questionnaire (ECQ) in general practice and to develop a clinical decision rule based on risk factors to enable GPs to easily assess the likelihood of peripheral arterial disease. DESIGN OF STUDY: An observational study. SETTING: General practice in The Netherlands. METHOD: This observational study included patients of > or =55 years visiting their GP for symptoms suggestive of intermittent claudication or with one risk factor. The ECQ and the ankle brachial index were performed. The prevalence of peripheral arterial disease, defined as an ankle brachial index <0.9, was related to risk factors using logistic regression analyses, on which a clinical decision rule was developed and related to the presence of peripheral arterial disease. RESULTS: Of the 4790 included patients visiting their GP with symptoms suggestive of intermittent claudication, 4527 were eligible for analyses. The prevalence of peripheral arterial disease in this group was 48.3%. The sensitivity of the ECQ was only 56.2%. The prevalence of peripheral arterial disease in a clinical decision rule that included age, male sex, smoking, hypertension, hypercholesterolemia, and a positive ECQ, increased from 14% in the lowest to 76% in the highest category. CONCLUSION: This study indicates that the ECQ alone has an inadequate diagnostic value in detecting patients with peripheral arterial disease. The ankle brachial index should be performed to diagnose peripheral arterial disease in patients with complaints suggestive of intermittent claudication, although our clinical decision rule could help to differentiate between extremely high and lower prevalence of peripheral arterial disease.     

Reduced susceptibility to dextran sulphate sodium-induced colitis in the interleukin-2 heterozygous (IL-2) mouse

Summary Mice homozygous for an inactivation of the interleukin-2 (IL-2) gene develop a T-cell dependent colitis. Heterozygous (IL-2+/-) mice are clinically healthy but have been shown to express reduced levels of IL-2 in the colon. Splenocytes from the IL-2+/- mice had a poorer proliferative response to polyclonal T-cell activation and these mice have reduced numbers of intestinal regulatory T cells (CD4+ CD25+ cells) when compared to wild type mice. When exposed to dextran sulphate sodium (DSS) IL-2+/- mice showed a markedly reduced susceptibility to DSS-induced colitis. While DSS treatment caused a marked increase in both CD4+ and CD8+ colonic T cells expressing increased levels of IL-2, IL-4, and IL-10 in wild type mice none of these changes were seen in IL-2+/- mice. On the contrary, cytokine expression in intestinal T cells of IL-2+/- mice was actually reduced after DSS treatment. These results suggest that reduced levels of IL-2 leads to attenuated activation and function of intestinal T cells in IL-2+/- mice and a failure to react adequately to DSS exposure.     

New Pseudoguaianolides from Ambrosia maritima

The investigation of the aerial parts of two collections of AMBROSIA MARITIMA afforded in addition to known pseudoguaianolides nine new ones including two nor-sesquiterpene lactones and two dimeric lactones. The structures were elucidated by highfield (1)H-NMR spectroscopy.     

Potency mismatch for behavioral and biochemical effects by dopamine receptor antagonists: implications for the mechanism of action of clozapine

Clozapine (3.8–60.0 µmol kg^?1) did not produce any alterations in DOPA accumulation (following inhibition of cerebral aromaticl-amino acid decarboxylase) in the prefrontal cortex or in three regions of the neostriatum, i.e. the ventral, the dorso-lateral and the posterior regions, in the rat. In contrast, clozapine produced a reduction in the 5-HTP accumulation in all these brain areas, except for the prefrontal cortex. Raclopride (0.08–20.0 µmol kg^?1) produced a marked increase in DOPA accumulation in all four brain regions and an increase in 5-HTP accumulation in the dorso-lateral neostriatum (2.5–20.0 µmol kg^?1), but not in the other forebrain regions. Treatment with SCH-23390 (0.4–1.6 µmol kg^?1) resulted in increased DOPA accumulation in the ventral and posterior parts of the neostriatum. No other changes in the DOPA or 5-HTP accumulation were seen with SCH-23390. Considering the doses of these three compounds needed for suppression of conditioned avoidance behavior and for the induction of cataleptic rigidity, it is concluded that raclopride produces an increased DA synthesis at much lower doses than those needed for behavioral effects. In contrast, the behavioral effects of SCH-23390 or clozapine precedes effects on brain DA synthesis on the dose-effect curve. In fact, the only biochemical effect of clozapine, which was observed in low, yet behaviorally active doses, was a decrease in forebrain 5-HTP accumulation. In conclusion, the present results demonstrate a mismatch, in different directions for raclopride and SCH-23390, as regards the doses needed to produce effects on brain dopamine synthesis and on behavior. Thus, the biochemical effects are seen with lower doses than the behavioral effects for the DA D₂ receptor blocking agent, whereas the opposite relationship is the case for the DA D₁ receptor antagonist. Taking these two DA receptor subtypes into consideration, the possibility should be considered that clozapine produces its antipsychotic-like behavioral effects on animal behavior primarily by a blockade of brain DA D₁, rather than D₂, receptors.     

High exposures to organic solvents among graffiti removers

Summary The exposure to organic solvents among 12 graffiti removers was studied. Health effects were also assessed by structured interview and a symptom questionnaire. Blood and urine samples were collected at the end of the day of air sampling. The concentrations of dichloromethane, glycol ethers, trimethylbenzenes and N-methyl-2-pyrrolidinone in the breathing zone of each worker were measured during one working day. The 8-h time-weighted average exposure to dichloromethane ranged from 18 to 1200 mg/m³. The Swedish Permissible Exposure Limit value for dichloromethane is 120 mg/m3. The air concentrations of glycol ethers, trimethylbenzens and N-methyl-2-pyrrolidinone were low or not detectable. No exposure-related deviations in the serum concentrations of creatinine, aspartate transaminase, alanine transaminase, -glutamyl transpeptidase or hyaluronan or the urine concentrations of ₁-microglobulin, R2-microglobulin or N-acetyl--glucos-aminidase were found. Irritative symptoms of the eyes and upper respiratory tract were more prevalent than in the general population. This study demonstrates that old knowledge about work harzards is not automatically transferred to new professions. Another aspect is that the public is also exposed as the job is performed during daytime in underground stations. At least for short periods, bystanders may be exposed to high concentrations of organic solvent vapours. People with predisposing conditions, e.g. asthmatics, may risk adverse reactions.     

Nimodipine and flunarizine have different effects on survival and morphology of PC12 cells during nerve growth factor deprivation

The purpose of this study was to examine the effect of antagonists of different subtypes of Ca(2+) channels (nimodipine and flunarizine) and two types of Ca(2+) chelating agents (the cell permeant Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid acetoxymethylester (BAPTA-AM) and the cell non-permeant Ca(2+) chelator EGTA) on neurite retraction and cell death of nerve growth factor (NGF)-differentiated PC12 cells after NGF deprivation. We demonstrated that flunarizine and nimodipine, but not BAPTA-AM and EGTA, provided protection against cell death due to NGF deprivation. Using time-lapse videomicroscopy and quantitative image analysis, we found that retraction of neurites was an early and fast phenomenon after removal of NGF. None of the compounds tested (flunarizine, nimodipine, BAPTA-AM, EGTA) could prevent the retraction of neurites.     

Renal antioxidant enzymes and fibrosis-related markers in the rat adriamycin model

Excessive generation of reactive oxygen intermediates can induce changes in the cellular antioxidant defence system. In this study we examine the antioxidant enzyme status and the expression of fibrosis-related marker proteins in the Adriamycin model of chronic renal failure in the rat. Twenty weeks after Adriamycin treatment, rats have overt nephrotic syndrome and renal failure with development of tubulo-interstitial fibrosis and glomerulosclerosis. Lipids accumulate in blood and in both glomeruli and tubulo-interstitial tissue. Desmin and alpha-smooth muscle actin expression increases in glomeruli and in the tubulo-interstitial area. Renal cortex antioxidant enzyme activities are decreased 20 weeks after Adriamycin injection (to 41% for catalase, to 56% for total superoxide dismutase and to 69% for glutathione peroxidase). The mRNA levels of catalase, Cu/Zn-superoxide dismutase and glutathione peroxidase-1 evaluated by Northern blot are decreased by more than 50% for catalase, Cu/Zn-superoxide dismutase and glutathione peroxidase-1. We conclude that in the rat Adriamycin-induced model of chronic renal failure with fibrosis, the combination of decreased antioxidant enzyme status in renal cortex with high concentrations of lipids in blood and renal tissue facilitates oxidative damage. Development of fibrosis is paralleled by increased expression of desmin and alpha-smooth muscle actin.