β-amyloid dynamics in human plasma

OBJECTIVES

To investigate dynamic changes in human plasma β-amyloid (Aβ) concentrations, evaluate the effects of aging and amyloidosis on these dynamics, and determine their correlation with cerebrospinal fluid (CSF) Aβ concentrations.

DESIGN

A repeated plasma and CSF sampling study.

SETTING

The Washington University School of Medicine in St Louis, Missouri.

PARTICIPANTS

Older adults with amyloid deposition (Amyloid+), age-matched controls without amyloid deposition (Amyloid-), and younger normal controls (YNCs) were enrolled for the study.

MAIN OUTCOME MEASURES

Hourly measurements of plasma Aβ were compared between groups by age and amyloidosis. Plasma Aβ and CSF Aβ concentrations were compared for correlation, linear increase, and circadian patterns.

RESULTS

Circadian patterns were observed in plasma Aβ, with diminished amplitudes with aging. Linear increase of Aβ was only observed for CSF Aβ in the YNC and Amyloid- groups, but not in the Amyloid+ group. No linear increase was observed for plasma Aβ. No significant correlations were found between plasma and CSF Aβ concentrations.

CONCLUSIONS

Plasma Aβ, like CSF, demonstrates a circadian pattern that is reduced in amplitude with increasing age but is unaffected by amyloid deposition. However, we found no evidence that plasma and CSF Aβ concentrations were related on an hourly or individual basis.

Influence of model and matrix on cytokine profile in rat and human

OBJECTIVE

Emerging evidence indicates that low-grade inflammation is part of the clinical picture of OA and that there is a need to identify soluble biomarkers of ongoing inflammation in the joint from a translational aspect. The aim of this study was to compare levels of pro-inflammatory biomarkers in SF, serum and/or EDTA plasma.

METHODS

SF and blood from rats subjected to Freund's complete adjuvant (FCA; n = 48) or monoiodoacetate (MIA; n = 88) monoarthritis and from control rats were collected over time. SF, EDTA plasma and serum were obtained from six individuals with OA of the knee and healthy controls. Levels of IL-6, KC/GRO, IL-8, monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 3α (MIP-3α), IL-1β, TNF and l(+)-lactate were assessed either by immune assay or by a colorimetric method.

RESULTS

Elevated levels of biomarkers were shown in monoarthritic animals in SF compared with the control groups, although with considerably lower magnitude in the MIA groups, which also indicated a biphasic pattern. Levels of KC/GRO and MIP-3α in serum from the FCA model and IL-6 in the MIA model followed the pattern of SF. In serum samples from OA individuals, MIP-3α correlated significantly with levels in SF.

CONCLUSION

While we found increased levels of markers in joint fluid and blood, no single systemic biochemical biomarkers that were a common denominator between the animal models and the patient material could be identified. Our data indicate that it is critical to delineate the temporal profile of multiple local and systemic factors in order to pinpoint soluble biomarkers for OA.

Plasma biomarkers associated with the apolipoprotein E genotype and Alzheimer disease

BACKGROUND

A blood-based test that could be used as a screen for Alzheimer disease (AD) may enable early intervention and better access to treatment.

OBJECTIVE

To apply a multiplex immunoassay panel to identify plasma biomarkers of AD using plasma samples from the Alzheimer's Disease Neuroimaging Initiative cohort.

DESIGN

Cohort study.

SETTING

The Biomarkers Consortium Alzheimer's Disease Plasma Proteomics Project.

PARTICIPANTS

Plasma samples at baseline and at 1 year were analyzed from 396 (345 at 1 year) patients with mild cognitive impairment, 112 (97 at 1 year) patients with AD, and 58 (54 at 1 year) healthy control subjects.

MAIN OUTCOME MEASURES

Multivariate and univariate statistical analyses were used to examine differences across diagnostic groups and relative to the apolipoprotein E (ApoE) genotype.

RESULTS

Increased levels of eotaxin 3, pancreatic polypeptide, and N-terminal protein B-type brain natriuretic peptide were observed in patients, confirming similar changes reported in cerebrospinal fluid samples of patients with AD and MCI. Increases in tenascin C levels and decreases in IgM and ApoE levels were also observed. All participants with Apo ε3/ε4 or ε4/ε4 alleles showed a distinct biochemical profile characterized by low C-reactive protein and ApoE levels and by high cortisol, interleukin 13, apolipoprotein B, and gamma interferon levels. The use of plasma biomarkers improved specificity in differentiating patients with AD from controls, and ApoE plasma levels were lowest in patients whose mild cognitive impairment had progressed to dementia.

CONCLUSIONS

Plasma biomarker results confirm cerebrospinal fluid studies reporting increased levels of pancreatic polypeptide and N-terminal protein B-type brain natriuretic peptide in patients with AD and mild cognitive impairment. Incorporation of plasma biomarkers yielded high sensitivity with improved specificity, supporting their usefulness as a screening tool. The ApoE genotype was associated with a unique biochemical profile irrespective of diagnosis, highlighting the importance of genotype on blood protein profiles.

On the corrosion and soiling effects on materials by air pollution in Athens, Greece

Abstract. In the frame of the European project, entitled MULTI-ASSESS, specimens of structural metals, glass, stone and concrete materials were exposed to air pollution at a station, which was installed for this purpose on a building, located in the centre of Athens. The main purpose of this project was to determine the corrosion and soiling effects of air pollution on materials. A set of the specimens was exposed in a position that was sheltered from rain and partly from wind, and another set was exposed in unsheltered positions on the roof of the above said building. In addition, other specimens were exposed at different heights on the same building, in order to investigate for the first time the corrosion and soiling effects on various materials as a function of height. For the determination of these effects, chemical analysis of the specimens was performed and basic parameters as the weight change, the layer thickness and the optical properties were calculated. Finally, the results obtained are discussed and their plausible interpretation is attempted.

Nitric acid and particulate matter measurements at Athens, Greece, in connection with corrosion studies

Abstract. For a long time, scientists have been concerned about the effects of air pollution on materials and especially on the monuments of the cultural heritage. The EU funded a project, entitled MULTI-ASSESS, to determine these effects and to develop dose-response functions appropriate for the new multi-pollutant environment. The University of Athens participated in this effort as a targeted field exposure test site. In the present paper, the measurements of the passive samplers, which were exposed during the same period with the samples for corrosion studies, at the Athens station, are presented. The results have shown that only 16.5% of the deposited mass was water soluble. The vertical distribution of passive particle collectors has led to the conclusion that the height of maximum deposition of each ion is different. In addition, a variation of the water-soluble mass to total deposited mass between 8% and 31% was observed.

Current asthma and respiratory symptoms among pupils in Shanghai, China: influence of building ventilation, nitrogen dioxide, ozone, and formaldehyde in classrooms

We investigated 10 naturally ventilated schools in Shanghai, in winter. Pupils (13-14 years) in 30 classes received a questionnaire, 1414 participated (99%). Classroom temperatures were 13-21 degrees C (mean 17 degrees C), relative air humidity was 36-82% (mean 56%). The air exchange rate was 2.9-29.4 ac/h (mean 9.1), because of window opening. Mean CO2 exceeded 1000 ppm in 45% of the classrooms. NO2 levels were 33-85 microg/m3 indoors, and 45-80 microg/m3 outdoors. Ozone were 1-9 microg/m3 indoors and 17-28 microg/m3 outdoors. In total, 8.9% had doctors' diagnosed asthma, 3.1% wheeze, 23.0% daytime breathlessness, 2.4% current asthma, and 2.3% asthma medication. Multiple logistic regression was applied. Observed indoor molds was associated with asthma attacks [odds ratio (OR) = 2.40: P < 0.05]. Indoor temperature was associated with daytime breathlessness (OR = 1.26 for 1 C; P < 0.001), and indoor CO2 with current asthma (OR = 1.18 for 100 ppm; P < 0.01) and asthma medication (OR = 1.15 for 100 ppm; P < 0.05). Indoor NO2 was associated with current asthma (OR = 1.51 for 10 microg/m3; P < 0.01) and asthma medication (OR = 1.45 for 10 microg/m3; P < 0.01). Outdoor NO2 was associated with current asthma (OR = 1.44 for 10 microg/m3; P < 0.05). Indoor and outdoor ozone was negatively associated with daytime breathlessness. In conclusion, asthma symptoms among pupils in Shanghai can be influenced by lack of ventilation and outdoor air pollution from traffic. Practical Implications Most urban schools in Asia are naturally ventilated buildings, often situated in areas with heavy ambient air pollution from industry or traffic. The classes are large, and window opening is the only way to remove indoor pollutants, but this results in increased exposure to outdoor air pollution. There is a clear need to improve the indoor environment in these schools. Building dampness and indoor mold growth should be avoided, and the concept of mechanical ventilation should be introduced. City planning aiming to situate new schools away from roads with heavy traffic should be considered.

Depletion of Vbeta5.2/5.3 T cells with a humanized antibody in patients with multiple sclerosis

A potentially pathogenic expansion of T cells expressing T cell receptor (TCR) Vbeta5.2/5.3 has been demonstrated in patients with multiple sclerosis (MS). A humanized antibody (ATM-027) directed against these T cells has been developed to further investigate the role of this subpopulation of T cells in MS. The pharmacokinetics/dynamics and safety of ATM-027 (0.3-300 mg intravenously over 30 min) were investigated in 14 patients with MS. The effect of treatment on cytokine expression and autoreactivity to peptides of myelin basic protein (MBP) was also studied. ATM-027 was well tolerated and raised no safety concerns. Clearance of the antibody was low and elimination half-life was approximately 3 weeks. The majority of the target Vbeta5.2/5.3 expressing T cells were depleted for at least 18 months. The small remaining fraction of target cells showed a marked decrease in their TCR expression, which was recovered within 8 months. The numbers of peripheral blood mononuclear cells (PBMCs) with spontaneous expression of IFN-gamma was decreased at 72 h and 8 weeks after treatment, whilst no clear effects on TNF-alpha, IL-4, IL-10, TGF-beta expression were observed. There was also a significant decrease in the number of PBMCs producing IFN-gamma in response to MBP peptide 80-102. We conclude that long-term depletion of T cells expressing defined Vbeta subgroups in MS patients is feasible using selective immunotherapy. The selective depletion of Vbeta5.2/5.3 expressing T cells in this study resulted in a decrease in potentially disease promoting anti-MBP reactivity and pro-inflammatory cytokine production.

Identification of fish species after cooking by SDS-PAGE and urea IEF: a collaborative study

A collaborative study, to validate the use of SDS-PAGE and urea IEF, for the identification of fish species after cooking has been performed by nine laboratories. By following optimized standard operation procedures, 10 commercially important species (Atlantic salmon, sea trout, rainbow trout, turbot, Alaska pollock, pollack, pink salmon, Arctic char, chum salmon, and New Zealand hake) had to be identified by comparison with 22 reference samples. Some differences in the recoveries of proteins from cooked fish flesh were noted between the urea and the SDS extraction procedures used. Generally, the urea extraction procedure appears to be less efficient than the SDS extraction for protein solubilization. Except for some species belonging to the Salmonidae family (Salmo, Oncorhynchus), both of the analytical techniques tested (urea IEF, SDS-PAGE) enabled identification of the species of the samples to be established. With urea IEF, two laboratories could not differentiate Salmo salar from Salmo trutta. The same difficulties were noted for differentiation between Oncorhynchus gorbuscha and Oncorhynchus keta samples. With SDS-PAGE, three laboratories had some difficulties in identifying the S. trutta samples. However, in the contrast with the previous technique, SDS-PAGE allows the characterization of most of the Oncorhynchus species tested. Only Oncorhynchus mykiss was not clearly recognized by one laboratory. Therefore, SDS-PAGE (Excel gel homogeneous 15%) appears to be better for the identification, after cooking, of fish such as the tuna and salmon species which are characterized by neutral and basic protein bands, and urea IEF (CleanGel) is better for the gadoid species, which are characterized by acid protein bands (parvalbumins). Nevertheless, in contentious cases it is preferable to use both analytical methods.

A standardized method of identification of raw and heat-processed fish by urea isoelectric focusing: a collaborative study

A urea-isoelectric focusing (urea-IEF) method of identifying fish species in processed fishery products was investigated as an interlaboratory collaborative study. The technique was optimized with respect to (i) protein extraction conditions, composition of the extraction solution (urea and SDS solutions), determination of protein concentrations of the fish extracts (five tested methods); (ii) nature of gel (with carrier ampholytes and Immobilines), conditions of rehydration of commercial dry gels, urea concentration; (iii) staining conditions, Coomassie blue and silver staining. The results of various experiments were compared to select the most appropriate methodology, with respect to the discrimination power of differentiating species with the minimal influence of heat processing, reproducibility, speed, and ease of application. The method recommended meets the requirements of food control and customs laboratories.

Field intercomparison of diffusive samplers for measuring ammonia

Agricultural production systems are recognised as a major source of atmospheric ammonia. Deposition of ammonia and ammonium may contribute to undesired changes in oligotrophic ecosystems. The continuous measurement of atmospheric ammonia requires expensive and sophisticated techniques and is performed only in a very restrict number of ambient air stations in Europe. Therefore, the application of passive samplers, which have the advantage of being easy to handle and cost-efficient, is useful. In the past the comparability of different passive samplers must be considered as rather scarce. In a joint European project under the leadership of the GSF-Forschungszentrum für Umwelt und Gesundheit, Neuherberg, in 1997 a comparison of different passive ammonia monitoring methods was carried out in a prealpine rural site near Garmisch-Partenkirchen. It was considered valuable to include not only well established systems but also methods still being developed. For the comparative test ten working groups with different methods took part. A wet annular denuder system, which has been developed by the Netherlands Energy Research Foundation for on-line measurement of atmospheric ammonia, served as reference of passive methods. The experiment, which started in June and finished in December, showed that most of the passive samplers fulfil the requirements and can be recommended for further measurements. Additional measurements of meteorological parameters were performed to check the influences of different weather conditions on passive sampling.

IFN-gamma treatment increases insulin binding and MHC class I expression in erythroleukemia cells

We have investigated if interferon-gamma (IFN-gamma) treatment of human K562 tumor cells, which upregulates the expression of MHC class I antigens (MHC-I), simultaneously would influence insulin binding. Treatment of K562 cells with recombinant human IFN-gamma for 48 h caused a significant increase of insulin binding at 37 degrees C. Recombinant human tumor necrosis factor-alpha (TNF-alpha) alone had no effect but acted synergistically with IFN-gamma, leading to a two-fold increase of insulin binding. No change in affinity, number of binding sites or cell surface expression of insulin receptors (IR) after IFN-gamma treatment could be detected. The increased insulin binding observed at 37 degrees C was not seen at 4 degrees C, suggesting alteration of insulin internalization. The dose-response curve, as well as the time curve, for the increase in insulin binding after IFN-gamma treatment correlated with enhanced cell surface expression of MHC-I antigens. However, the correlation was not absolute. Our results show that IFN-gamma treatment alone or together with TNF-alpha, can alter the insulin binding to K562 cells without changing the expression or affinity of the IR. This correlates with the effect of IFN-gamma on MHC-I expression. These results support the findings that MHC-I molecules associate and interact with the IR at the cell surface.

Regulation of lymphocyte aggregation and proliferation through adhesion molecule CD54 (ICAM-1)

The effect of two mouse mAb (LB-2 and G1B2) against human CD54 (intercellular adhesion molecule-1, ICAM-1) in lymphocyte aggregation and proliferation systems was investigated. The LB-2 mAb, but not G1B2, inhibited phorbol ester-induced aggregation of B lymphoblastoid cells. In addition, LB-2, but not G1B2, induced aggregation and proliferation of peripheral blood mononuclear cells (PBMC) in cultures containing FCS. The Fab fragment of LB-2 always (10/10 donors) induced proliferation while the intact mAb was active in 3/11 donors. When cultures contained human serum (HS), LB-2 and its Fab fragment induced proliferation in 1/9 and 1/4 donors, respectively. Addition of HS to FCS cultures inhibited proliferation induced by LB-2 Fab, indicating the presence of an inhibitory factor in human serum. Addition of anti-CD18 mAb to cultures stimulated by LB-2 Fab caused partial inhibition of proliferation but did not prevent aggregate formation. A combination of anti-CD18 and anti-CD29 mAb resulted in a nearly complete inhibition of proliferation but did not inhibit aggregate formation. In these experiments it was found that the anti-CD29 mAb 4B4 in itself induced cell aggregation of PBMC and enhanced aggregation induced by the anti-CD3 mAb OKT3. Both LB-2 and G1B2 showed significant inhibition (> 60%) of proliferation when human PBMC were stimulated by the antigen PPD in the presence of HS, but not when stimulated by staphylococcal enterotoxin A (SEA) or IL-2. This study describes two mAb against separate epitopes on CD54 which are differentially involved in cell aggregation or induction of proliferation but are of similar importance in antigen-specific responses. Furthermore, the new finding that the LB-2 mAb or its Fab fragment can induce cell aggregation and proliferation defines a signaling function of CD54 which may work independent of crosslinking or costimulation.

Presence of human 65 kD heat shock protein (hsp) in inflamed joints and subcutaneous nodules of RA patients

Monoclonal antibodies to the human homologue of the bacterial 65 kD heat shock protein (hsp) were used to investigate the tissue distribution of endogenous hsp 65 in normal versus rheumatoid synovial tissue, in subcutaneous nodules of patients with rheumatoid arthritis (RA) and in several instances of non-rheumatoid inflammation. A strong reactivity of the anti-hsp antibody was found in the cartilage-pannus junction in rheumatoid joints and in rheumatoid nodules, but not in normal joints or in normal or inflamed kidney or liver (irreversible graft rejection, chronic glomerulonephritis or primary biliary cirrhosis). The findings provide a new hypothetical explanation for a role of T cells reactive with the 65 kD hsp in the generation of both articular and extra-articular lesions in chronic rheumatoid arthritis.

Interferon is able to reduce tumor cell susceptibility to human lymphokine-activated killer (LAK) cells

It is known that IL-2 induces lymphocytes to produce interferon-gamma (IFN-gamma) and this IFN type is particularly efficient in inducing tumor cell resistance to natural killer (NK) cell-mediated lysis. We have investigated the effect of IFN on tumor cell sensitivity to LAK cell-mediated cytotoxicity. Pretreatment of the human K562 leukemia and HHMS melanoma with IFN-gamma and the Daudi lymphoma with IFN-alpha caused a significant reduction in sensitivity to lysis by human LAK cells generated in vitro in the presence of human recombinant IL-2 (100 U/ml). The LAK activity was mediated by cells expressing NK cell markers (CD16,NKH1) as well as by cells with T cell markers (CD3, CD5). IFN-treated K562 cells were protected from lysis mediated by all these populations. Supernatants from LAK cultures containing IFN-gamma were able to induce NK and LAK resistance when used to pretreat K562 overnight. Antibodies to IFN-gamma but not to IFN-alpha were able to neutralize this activity. Taken together, these results indicate that the production of IFN-gamma by LAK cells may be of importance in induction of tumor cell resistance to LAK cell-mediated lysis.

Anti-keyhole limpet hemocyanin antibody in normal unsensitized individuals

Antibody to keyhole limpet hemocyanin (KLH) has been detected in normal unimmunized subjects by means of a sensitive micropassive hemagglutination technique. Prior sensitization was not detected by either skin testing or lymphocyte transformation. After immunization with KLH there was no correlation between the level of this antibody and subsequently acquired skin test reactivity and lymphocyte transformation.