256 research outputs found
The detection of Helicobacter pylori in paraffin sections using the PCR technique and various primers as compared to histological techniques
Helicobacter pylori is thought to represent a significant etiopathogenic factor in
diseases of the upper gastrointestinal tract. It seems, therefore, important to elaborate
effective techniques for its detection. The aim of the present study was to
evaluate the effectiveness of Helicobacter pylori detection using the PCR technique
on paraffin sections with various pairs of primers and to compare the results
with those of a histological appraisal. Material for the studies involved 50 paraffin
blocks with gastric mucosa biopsies fixed in 4% buffered formalin. In this material
4 tests were performed with the aim of diagnosing Helicobacter pylori infection:
1) H+E staining, 2) staining by the Giemsa technique, 3) an immunocytochemical
technique with antibodies against H. pylori and 4) the PCR technique with various
primers. In the present study the most reliable results for H. pylori detection as
well as the most pronounced correlation were obtained by using the PCR technique
with primers for the ureC gene, immunohistochemistry and staining according
to Giemsa. Less compatible results were obtained employing the two PCR
techniques which utilise various primers. The experiments confirmed the usefulness
of the PCR technique in the detection of Helicobacter pylori in paraffin sections
by using a suitable pair of primers, and also indicated that Giemsa staining
and immunohistochemistry should be taken into account
Experiment assessment of mass effects in the rat_ implications for small animal PET imaging
In vivo imaging using positron emission tomography (PET) is important in the development of new radiopharmaceuticals in rodent
animal models for use as biochemical probes, diagnostic agents, or in drug development. We have shown mathematically that, if small
animal imaging studies in rodents are to have the same âqualityâ as human PET studies, the same number of coincidence events must be
detected from a typical rodent imaging âvoxelâ as from the human imaging voxel. To achieve this using the same specifi activity
preparation, we show that roughly the same total amount of radiopharmaceutical must be given to a rodent as to a human subject. At high
specifi activities, the mass associated with human doses, when administered to a rodent, may not decrease the uptake of radioactivity at
non saturable sites or sites where an enzyme has a high capacity for a substrate. However, in the case of binding sites of low density such
as receptors, the increased mass injected could saturate the receptor and lead to physiologic effects and non-linear kinetics. Because of the
importance of the mass injected for small animal PET imaging, we experimentally compared high and low mass preparations using ex vivo
biodistribution and phosphorimaging of three compounds: 2-fluoro-2-deoxyglucos (FDG), 6-fluoro-L-metatyrosin (FMT) and one
receptor-directed compound, the serotonin 5HT1A receptor ligand, trans-4-fluoro-N-{2-[4-(2-methoxylphenyl piperazino]ethyl}-N-(2-
pyridyl) cyclohexane- carboxamide (FCWAY). Changes in the mass injected per rat did not affect the distribution of FDG, FMT, and
FCWAY in the range of 0.6 â1.9 nmol per rat. Changes in the target to nontarget ratio were observed for injected masses of FCWAY in
the range of 5â50 nmol per rat. If the specifi activity of such compounds and/or the sensitivity of small animal scanners are not increased
relative to human studies, small animal PET imaging will not correctly portray the âtrueâ tracer distribution. These difficultie will only be
exacerbated in animals smaller than the rat, e.g., mice.Publicad
Elevated nuclear S100P expression is associated with poor survival in early breast cancer patients
Initial results from a PET/planar small animal imaging system
A pair of stationary, opposed scintillation detectors in time
coincidence is being used to create planar projection or
tomographic images of small animals injected with positronemitting
radiotracers. The detectors are comprised of arrays
of individual crystals of bismuth germanate coupled to
position-sensitive photomultiplier tubes. The system uses
FERA (LeCroy Research Systems) charge-sensitive ADCs
and a low cost digital YO board as a E R A bus-to-host bridge.
In projection mode, the animal is placed within the 55 mm x
45 mm useful field-of-view of the detectors and images are
formed from coincidence lines that fall close to the normals of
both detectors. In tomographic mode, the animal is placed on
a rotation stage between the detectors and rotated around a
vertical axis to acquire all possible lines-of-response.
Tomographic images are then reconstructed from those lines
falling within a user-specified angle of each detector normal.
In mice, the system is capable of high-speed, whole-body
dynamic projection imaging, and whole body tomographic
imaging of slowly varying tracer distributions. An ECG gating capability is also available for evaluating cardiac
function. This system is currently being used to study tracer
transport in normal and genetically engineered mice.Publicad
Initiation of Aspirin Therapy Modulates Angiogenic Protein Levels in Women with Breast Cancer Receiving Tamoxifen Therapy
Abstract Aspirin has a range of antineoplastic properties linked to inhibition of cyclooxygenase enzymes in tumor cells, platelet inhibition and to inhibition of angiogenesis. We undertook a prospective study to determine the influence of a 45âday course of aspirin therapy on circulating and intraplatelet levels of selected proangiogenic (vascular endothelial growth factor [VEGF]) and antiangiogenic (thrombospondinâ1 [TSPâ1]) proteins, and platelet protein release in women diagnosed with breast cancer who were receiving tamoxifen therapy. Initiation of aspirin therapy increases serum and intraplatelet levels of TSPâ1 without a corresponding increase in VEGF levels. Following aspirin therapy, VEGF levels decreased (relative to pretreatment levels) while TSPâ1 returned to pretreatment levels. Plasma TSPâ1 and VEGF levels did not change on aspirin therapy. Aspirin use also decreased thrombin receptor mediated release of TSPâ1 and VEGF from platelets. The selective impact on platelet angiogenic protein content and release supports one mechanism by which aspirin can modify the angiogenic balance in women receiving tamoxifen therapy. Aspirin therapy appears to favor an overall antiangiogenic balance in women with breast cancer who are receiving tamoxifen therapy
Monitoring the correction of glycogen storage disease type 1a in a mouse model using [18F]FDG and a dedicated animal scanner
Monitoring gene therapy of glycogen storage disease type 1a in a mouse model was achieved using [18F]FDG and a dedicated animal scanner. The G6Pase knockout (KO) mice were compared to the same mice after infusion with a recombinant adenovirus containing the murine G6Pase gene (Ad-mG6Pase). Serial images of the same mouse before and after therapy were obtained and compared with wild-type (WT) mice of the same strain to determine the uptake and retention of [18F]FDG in the liver. Image data were acquired from heart, blood pool and liver for twenty minutes after injection of [18F]FDG. The retention of [18F]FDG was lower for the WT mice compared to the KO mice. The mice treated with adenovirus-mediated gene therapy had retention similar to that found in age-matched WT mice. These studies show that FDG can be used to monitor the G6Pase concentration in liver of WT mice as compared to G6Pase KO mice. In these mice, gene therapy returned the liver function to that found in age matched WT controls as measured by the FDG kinetics in the liver compared to that found in age matched wild type controlsPublicad
Lack of neuroinflammation in the HIV-1 transgenic rat: An [18 F]-DPA714 PET imaging study
BACKGROUND: HIV-associated neuroinflammation is believed to be a major contributing factor in the development of HIV-associated neurocognitive disorders (HAND). In this study, we used micropositron emission tomography (PET) imaging to quantify neuroinflammation in HIV-1 transgenic rat (Tg), a small animal model of HIV, known to develop neurological and behavioral problems. METHODS: Dynamic [(18)F]DPA-714 PET imaging was performed in Tg and age-matched wild-type (WT) rats in three age groups: 3-, 9-, and 16-month-old animals. As a positive control for neuroinflammation, we performed unilateral intrastriatal injection of quinolinic acid (QA) in a separate group of WT rats. To confirm our findings, we performed multiplex immunofluorescent staining for Iba1 and we measured cytokine/chemokine levels in brain lysates of Tg and WT rats at different ages. RESULTS: [(18)F]DPA-714 uptake in HIV-1 Tg rat brains was generally higher than in age-matched WT rats but this was not statistically significant in any age group. [(18)F]DPA-714 uptake in the QA-lesioned rats was significantly higher ipsilateral to the lesion compared to contralateral side indicating neuroinflammatory changes. Iba1 immunofluorescence showed no significant differences in microglial activation between the Tg and WT rats, while the QA-lesioned rats showed significant activation. Finally, cytokine/chemokine levels in brain lysates of the Tg rats and WT rats were not significantly different. CONCLUSION: Microglial activation might not be the primary mechanism for neuropathology in the HIV-1 Tg rats. Although [(18)F]DPA-714 is a good biomarker of neuroinflammation, it cannot be reliably used as an in vivo biomarker of neurodegeneration in the HIV-1 Tg rat. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12974-015-0390-9) contains supplementary material, which is available to authorized users
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Polyimides and their derivatives for gas separation applications
High performance polymers are of interest for high temperature gas separations, especially for the sequestration of carbon dioxide. A new family of high performance imide polymers (VTEC, RBI Inc.) has been identified as a material class containing the potential building blocks needed for a successful membrane capture material. The VTEC polyimides possess the desired thermal properties (up to 500 °C) and are robust and flexible even after multiple thermal cycles (up to 400 °C). A critical variable when working with the glassy polymers is their moisture content. It has been found that water entrapped within the polymer matrix (either as hydration molecules attached to salts in the polymer, left over solvent, or physisorbed) can also cause the polymer to change dramatically. Additionally presence of molecular water in the polymerâs void volume has been validated through Positron Annihilation Lifetime (PAL) spectroscopy. In this presentation, polymer characterization and gas-separation testing results will be discussed
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