Fixation methods for electron microscopy of human and other liver

For an electron microscopic study of the liver,expertise and complicated,time-consuming processing of hepatic tissues and cells is needed.The interpretation of electron microscopy(EM) images requires knowledge of the liver fine structure and experience with the numerous artifacts in fixation,embedding,sectioning,contrast staining and microscopic imaging.Hence,the aim of this paper is to present a detailed summary of different methods for the preparation of hepatic cells and tissue,for the purpose of preserv...     

Visualization of cerebral microbleeds with dual‐echo T2*‐weighted magnetic resonance imaging at 7.0 T

Purpose:

To assess the visualization of cerebral microbleeds with dual echo T2*‐weighted imaging at 7.0 T magnetic resonance imaging (MRI).

Materials and Methods:

Ten consecutive participants (eight men, two women, mean age 54 ± 12 years) with vascular disease or risk factors from the second manifestations of arterial disease (SMART) study were included. Dual‐echo T2*‐weighted scans (echo time: 2.5/15.0 msec) were made for all participants at 7.0 T MRI. The number of visible microbleeds and the diameter of the microbleeds were recorded on minimal intensity projection images of both echoes.

Results:

The first echo image shows dark microbleeds against a homogeneous, more hyperintense signal of the brain tissue without contrast for veins and basal ganglia. In eight patients microbleeds were observed, with a total of 104 microbleeds. Of these, 88 (84.6%) were visible on the first and 102 (98.0%) on the second echo. The mean diameter of the microbleeds was 1.24 mm for the first echo and 2.34 mm for the second echo.

Conclusion:

T2*‐weighted imaging at two echo times at 7.0 T combines the advantages of the first and second echo. Microbleeds visible on the first echo show large contrast with the surrounding tissue, even in the presence of paramagnetic ferritin. The second echo enables visualization of smaller microbleeds than the first echo. J. Magn. Reson. Imaging 2010;32:52–59. © 2010 Wiley‐Liss, Inc.     

Fluid attenuated inversion recovery (FLAIR) MRI at 7.0 Tesla: comparison with 1.5 and 3.0 Tesla

Purpose

To assess fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) at three field strengths, regarding signal-to-noise ratio (SNR), contrast and signal homogeneity, in order to determine the potential gain and current challenges of FLAIR at ultra-high field strength (7 T).

Methods

FLAIR images of five healthy volunteers (age 24?±?4 years, 4 male) were acquired at 1.5 T, 3 T and 7 T. Image homogeneity and visibility of normal brain structures were evaluated. SNR of grey matter (GM), white matter (WM) and cerebrospinal fluid (CSF) were measured in regions not affected by transmit field heterogeneity.

Results

The SNR (mean ± SD) at 7 T (GM 168?±?15, WM 125?±?11) increased slightly more than proportionally, compared with at 1.5 T (GM 30?±?3, WM 22?±?2) and 3 T (GM 62?±?7, WM 44?±?4). Relative contrast between GM and WM at 7 T (1.35?±?0.07) was slightly less than at 3 T (1.42?±?0.14) or 1.5 T (1.37?±?0.07). Several major fibre bundles became visible at 7 T. One incidentally observed white matter lesion was well visible at all field strengths.

Conclusion

Image homogeneity remains challenging and should be improved by future technical developments. FLAIR imaging at 7 T yields a high SNR,with better contrast for WM substructures and the iron-bearing basal ganglia, and has potential for good conspicuity of WM lesions.     

Mood disorders and serotonin transporter density in ecstasy users—the influence of long-term abstention, dose, and gender

Rationale Neurotoxic effects of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) on the serotonin (5-HT) system have been described in animals and humans, but little is known about long-term effects of ecstasy use on mood.Objectives To investigate short-term and long-term effects of ecstasy use on mood and its association with 5-HT neurotoxicity, dose, and gender in humans.Methods Fifteen moderate ecstasy users, 23 heavy ecstasy users, 16 former heavy ecstasy users and 15 drug-using, but ecstasy-naive controls were included. Mood was assessed using the Composite International Diagnostic Interview (CIDI) and the Beck Depression Inventory (BDI). Outcomes were correlated with 5-HT transporter (SERT) density, assessed with [¹²³I]-CIT single photon emission computed tomography (SPECT).Results The prevalence of mood disorders assessed by CIDI did not differ between all groups. The overall test for differences in BDI scores between groups was near significance (P=0.056), with BDI scores higher in former heavy ecstasy users than in ecstasy-naive controls (P=0.045). BDI scores were correlated with the total number of ecstasy tablets used (r=0.310; P=0.021). No associations between CIDI or BDI outcomes and SERT density or gender were observed.Conclusions These results suggest that ecstasy use is not associated with clinical depression (CIDI). However, the number of ecstasy tablets taken lifetime was associated with higher BDI scores for depressive mood, and this relationship seemed to persist after ecstasy use had stopped. We did not find that depressed mood in ecstasy users was associated with decrease in SERT density. Prospective studies are needed to establish the causal relationship between ecstasy use and depressed mood.     

Development of antibodies against pneumococcal proteins alpha-enolase, immunoglobulin A1 protease, streptococcal lipoprotein rotamase A, and putative proteinase maturation protein A in relation to pneumococcal carriage and Otitis Media

Surface associated pneumococcal proteins alpha-enolase (Eno), immunoglobulin A1 protease (Iga), streptococcal lipoprotein rotamase A (SlrA), and putative proteinase maturation protein A (PpmA) have potential as candidates for future protein-based anti-pneumococcal vaccines. The immunogenicity of these proteins were studied in a cohort of 329 children during their first two years of life. During the first recorded episode of otitis media, acute and convalescent phase sera were available from 151 children. Concentrations of antibodies against Eno, Iga, SlrA and PpmA were measured by EIA and detected in 99% (300/302), 95% (288/302), 95% (288/302), and 83% (251/302) of the sera, respectively. There were no statistically significant differences between the groups of children with and without a history of pneumococcal contact or with respect to the type of pneumococcal contact. Despite a mean overall decrease in the antibody titers in the convalescent sera following AOM, several children were able to respond with a more than twofold increase in antibody titer in response to AOM. The majority of the children with increased antibody concentrations appeared in the groups, which were colonized with pneumococci at the time of serum collection, but were recorded as having no prior contact with pneumococci. In conclusion, SlrA, PpmA, Eno and Iga are immunogenic proteins that elicit antibody responses early in life. No significant correlation between antibody titers to these proteins and pneumococcal carriage or infection was found. Presumably, this results from the presence of cross-reactive epitopes on commensal bacteria.     

"The good life" for demented persons living in nursing homes

BACKGROUND: This study investigated which concepts regarding "the good life" are used in mission statements of nursing homes providing care for demented patients. METHOD: All 317 Dutch nursing homes caring for demented patients were asked to participate; of these, 69% responded. Their mission statements were qualitatively analyzed on content. Whether different types of nursing home differed significantly in the content of their mission statements was investigated by means of chi2 analyses. RESULTS: Six main concepts were found that are considered important for a good life: 1) autonomy and freedom, 2) individuality and lifestyle, 3) relationships and social networks, 4) warmth and safety and familiarity, 5) developing capacities and giving meaning to life and 6) subjective experience and feelings of well-being. It was found that mission statements specifically developed for demented patients attach less importance to the concepts 1) autonomy and freedom and 2) individuality and lifestyle, than mission statements which are also aimed at non-demented residents. Most mission statements turned out to be highly eclectic in content. CONCLUSION: Nursing homes with a separate statement for demented residents seem to acknowledge the special position of demented residents and the tension between dementia and the ideal of autonomy. Although the eclecticism found in mission statements is understandable, a coherent view on the good life for demented residents should aim for a sound internal structure, and make choices between values. Only then can mission statements provide real guidance for everyday care.     

Monoclonal antibodies to P2 basic protein and their use in the investigation of some aspects of the Guillain-Barré syndrome

The production and characterization of two mouse monoclonal antibodies (MAbs) raised against human basic protein P2 is described. The two MAbs recognise two non-overlapping epitopes on P2. Using these two MAbs as a probe, a search was made for the presence of anti-idiotype (Ab2) antibodies directed against anti-P2 (Ab1) autoantibodies in sera of patients with Guillain-Barré syndrome (GBS). In sera of twenty GBS patients no such Ab2 antibodies could be demonstrated. Epitopes present on cytomegalo virus- or Epstein-Barr virus-infected cells, which may play a part in triggering GBS, were not recognised by the two MAbs.     

Angioplasty for stable versus unstable angina pectoris: Are unstable patients more likely to get restenosis?

Summary Current evidence with regard to the possible association between clinical expression of coronary disease prior to the time of angioplasty, and the subsequent risk of restenosis following successful dilatation, remains inconclusive.To prospectively compare the incidence of restenosis in stable versus unstable angina pectoris patients, follow-up angiography was performed in 85 percent of patients from a consecutive series with a successful PTCA, irrespective of presence or absence of recurrent ischemic symptoms. Furthermore, changes in lesion severity were assessed quantitatively by an automated edge-detection technique rather than visual analysis. Employing such a study design and follow-up protocol, it was found that the incidence of restenosis in patients with stable coronary artery disease was similar to that of patients with unstable rest angina, irrespective of the type of angiographic definition used.H.E. Luijten, MD, is the recipient of a Research Fellowship from the Dutch Heart Foundation (no. 85–118).K.J. Beatt, MD, MRCP, is the recipient of a Research Fellowship from the British and Dtuch Heart Foundations.