PCR detection of amplified 132 bp repeats in Marek's disease virus type 1 (MDV-1) DNA can serve as an indicator for critical genomic rearrangement leading to the attenuation of virus virulence

A radioactive PCR test was developed that amplified the very virulent Marek's disease virus-1 (vvMDV-1) DNA sequence containing the 132 bp repeats. In apathogenic MDV-1 (CVI 988, Rispens), amplified DNA bands containing multiple copies of 132 bp repeats were identified. In the present study this PCR technique was used to monitor the passage level of vvMDV-1 in chicken embryo fibroblasts (CEF) in which the number of tandem 132 bp repeats was increased. It was found that at passage level 32 of vvMDV-1-B isolate, the 132 bp tandem repeat was already markedly amplified and its pattern resembled that of the MDV-1 (CVI 988, Rispens) vaccine virus DNA. In the vvMDV-1Z strain, amplification of the 132 bp repeat was not detectable at a similar passage level. The PCR test demonstrated that the apathogenic MDV-1 Md11/75c virus developed by extensive in vitro passaging has amplified 132 bp DNA repeats similar to those of the commercial vaccine virus (CVI 988, Rispense). It was also found that the pattern of viral RNA from infected cells detectable by Northern blot hybridization was markedly changed from a 2.4 kb RNA species in cells infected with vvMDV-1 viruses, to four RNA species (ranging from 2.2 to 4.4 kb) in cells infected with passage 32 of MDV-1-B strain, to a very large number of undefined RNA species synthesized in cells infected with attenuated MDV-1 viruses (CVI 988, Rispens and Md 11/75c).     

The antiatherogenic effect of allicin: possible mode of action.

OBJECTIVE: Garlic (Allium sativum) has been suggested to affect several cardiovascular risk factors. Its antiatherosclerotic properties are mainly attributed to allicin that is produced upon crushing of the garlic clove. Most previous studies used various garlic preparations in which allicin levels were not well defined. In the present study, we evaluated the effects of pure allicin on atherogenesis in experimental mouse models. METHODS AND RESULTS: Daily dietary supplement of allicin, 9 mg/kg body weight, reduced the atherosclerotic plaque area by 68.9 and 56.8% in apolipoprotein E-deficient and low-density lipoprotein (LDL) receptor knockout mice, respectively, as compared with control mice. LDL isolated from allicin-treated groups was more resistant to CuSO(4)-induced oxidation ex vivo than LDL isolated from control mice. Incubation of mouse plasma with (3)H-labeled allicin showed binding of allicin to lipoproteins. By using electron spin resonance, we demonstrated reduced Cu(2+) binding to LDL following allicin treatment. LDL treatment with allicin significantly inhibited both native LDL and oxidized LDL degradation by isolated mouse macrophages. CONCLUSIONS: By using a pure allicin preparation, we were able to show that allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages.     

Enhanced 3D PET OSEM reconstruction using inter-update Metz filtering

We present an enhancement of the OSEM (ordered set expectation maximization) algorithm for 3D PET reconstruction, which we call the inter-update Metz filtered OSEM (IMF-OSEM). The IMF-OSEM algorithm incorporates filtering action into the image updating process in order to improve the quality of the reconstruction. With this technique, the multiplicative correction image--ordinarily used to update image estimates in plain OSEM--is applied to a Metz-filtered version of the image estimate at certain intervals. In addition, we present a software implementation that employs several high-speed features to accelerate reconstruction. These features include, firstly, forward and back projection functions which make full use of symmetry as well as a fast incremental computation technique. Secondly, the software has the capability of running in parallel mode on several processors. The parallelization approach employed yields a significant speed-up, which is nearly independent of the amount of data. Together, these features lead to reasonable reconstruction times even when using large image arrays and non-axially compressed projection data. The performance of IMF-OSEM was tested on phantom data acquired on the GE Advance scanner. Our results demonstrate that an appropriate choice of Metz filter parameters can improve the contrast-noise balance of certain regions of interest relative to both plain and post-filtered OSEM, and to the GE commercial reprojection algorithm software.     

The response of ataxia-telangiectasia homozygous and heterozygous skin fibroblasts to neocarzinostatin

Skin fibroblast strains from patients with ataxia-telangiectasia(A-T) were recently reported to be hypersensitive to the antitumorantibiotic neocarzinostatin (NCS). In this study, the distinctintermediate degree of NCS sensitivity previously shown withtwo strains of A-T heterozygous fibroblasts was extended andconfirmed in an additional eight strains. A sensitivity baselinefor A-T heterozygous cells has thus been established and mayserve for the laboratory diagnosis of A-T heterozygotes, a cancer-pronepopulation. The response of A-T homozygous and heterozygouscells to NCS was further characterized by two molecular parameters,DNA repair synthesis and inhibition of DNA replication. Thepattern of dose response with regard to DNA repair synthesis,as assayed by the benzoylated naphthoylated DEAE cellulose chromatographymethod, was similar in normal, A-T homozygous and A-T heterozygouscells, although certain variability between strains was observedwith regard to the amount of repair incorporation. This findingcorrelates with a similar observation made with the same cellstrains following -irradiation. Inhibition of DNA synthesisfollowing NCS treatment was reduced in A-T homozygous cells,as compared to normal cells, but the "Inhibition resistant"component of DNA synthesis typically observed following treatmentwith low doses of X-rays or bleomycin was not observed withNCS. A-T heterozygous cells showed somewhat less inhibitionof DNA synthesis than normal cells following NCS treatment,although this difference was small and was not significant enoughto serve as an additional laboratory diagnostic aid. It is concludedthat the reduced inhibition of DNA synthesis, rather than reducedextent of DNA repair synthesis, correlates with the cellularhypersensitivity of A-T homozygous cells. This hypersensitivityseems to be observed primarily, if not exclusively, with DNAbreaking agents.     

Transcranial magnetic stimulation of the ventromedial prefrontal cortex impairs theory of mind learning

Imaging and lesion studies indicate that the prefrontal cortex plays a prominent role in mediating theory of mind (ToM) functioning. Particularly, the ventromedial prefrontal cortex (VMPFC) appears to be involved in mediating ToM functioning. This study utilized slow repetitive transcranial magnetic stimulation (rTMS) over the VMPFC in 13 healthy subjects in order to test whether normal functioning of the VMPFC is necessary for ToM functioning. We found that rTMS to the VMPFC, but not sham-rTMS, significantly disrupted ToM learning. Performance on a control task, not involving affective ToM functioning, was not significantly altered after applying rTMS to the VMPFC or sham-rTMS. In an additional experiment, rTMS to the vertex did not significantly affect ToM learning, confirming specificity of the VMPFC region. These findings indicate that the VMPFC is critical for intact ToM learning and shed further light on the concept and localization of ToM in particular and empathic functioning in general.