Comparison between 1.5T and 3.0T MRI: both field strengths sensitively detect subclinical inflammation of hand and forefoot in patients with arthralgia.

OBJECTIVE: Magnetic resonance imaging (MRI) of small joints sensitively detects inflammation. This inflammation, and tenosynovitis in particular, has been shown to predict rheumatoid arthritis (RA) development in arthralgia patients. These data have predominantly been acquired on 1.0-1.5 T MRI. However, 3.0 T is now commonly used in practice. Evidence on the comparability of these field strengths is scarce and has never included subtle inflammation in arthralgia patients or tenosynovitis. Therefore, we assessed the comparability of 1.5 T and 3.0 T in detecting subclinical inflammation in arthralgia patients. METHOD: A total of 2968 locations (joints, bones, tendon sheaths) in the hands and forefeet of 28 patients with small-joint arthralgia, at risk for RA, were imaged on both 1.5 and 3.0 T MRI. Two blinded readers independently scored erosions, osteitis, synovitis, and tenosynovitis, in line with the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS). Features were summed into inflammation (osteitis, synovitis, tenosynovitis) and RAMRIS (inflammation and erosions). Agreement was assessed with intraclass correlation coefficients (ICCs) for continuous scores and after dichotomization into presence or absence of inflammation, on patient and location levels. RESULTS: Interreader ICCs were excellent (> 0.90). Comparing 1.5 and 3.0 T revealed an ICC of 0.90 for inflammation and RAMRIS. ICCs for individual inflammation features were: tenosynovitis 0.87 (95% confidence interval 0.74-0.94), synovitis 0.65 (0.24-0.84), and osteitis 0.96 (0.91-0.98). Agreement was 83% for inflammation and 89% for RAMRIS. Analyses on the location level showed similar results. CONCLUSION: Agreement on subclinical inflammation between 1.5 T and 3.0 T was excellent. Although synovitis scores were slightly different, synovitis often occurs simultaneously with other inflammatory signs, suggesting that scientific results on the predictive value of MRI-detected inflammation for RA, obtained on 1.5 T MRI, can be generalized to 3.0 T MRI.

Do magnetic resonance imaging-detected erosions predict progression to rheumatoid arthritis in patients presenting with clinically suspect arthralgia? A longitudinal study.

Objective: Radiographic joint erosions are a hallmark of rheumatoid arthritis (RA). Magnetic resonance imaging (MRI) is more sensitive than radiographs in detecting erosions. It is unknown whether MRI-detected erosions are predictive for RA development in patients with clinically suspect arthralgia (CSA). Therefore, we investigated the prognostic value of MRI-detected erosions, defined as any MRI erosion, or MRI erosion characteristics that were recently identified as specific for RA in patients with evident arthritis. Method: Patients presenting with CSA (n = 490) underwent contrast-enhanced 1.5 T MRI of the wrist, metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints. MRIs were scored according to the Rheumatoid Arthritis Magnetic Resonance Imaging Scoring system (RAMRIS). Presence of any MRI erosion (present in < 5% of symptom-free controls) and RA-specific erosion characteristics as identified previously (grade ≥ 2 erosions, erosions in MTP5, erosions in MTP1 if aged < 40 years) were studied with clinically apparent inflammatory arthritis development as outcome. Analyses were corrected for age and MRI-detected subclinical inflammation. Results: Erosions were present in 20%. Presence of any MRI erosion was not associated with arthritis development [multivariable analysis hazard ratio (HR) 0.97 (95% confidence interval 0.59-1.59)]. The different RA-specific erosion characteristics were not predictive [grade ≥ 2 HR 1.05 (0.33-3.34), erosions in MTP5 HR 1.08 (0.47-2.48), and MTP1 if aged < 40 years HR 1.11 (0.26-4.70)]. Erosion scores were higher in anti-citrullinated protein antibody (ACPA)-positive than in ACPA-negative patients (median 2.0 vs 1.0, p = 0.002), and related to more subclinical inflammation. Within both subgroups, MRI erosions were not predictive. Conclusions: MRI-detected erosions in hands and feet were not predictive for inflammatory arthritis development. Therefore, evaluating MRI for erosions in addition to subclinical inflammation does not provide added clinical value in CSA.

Undifferentiated carcinoma of the pancreas in a cockatiel (Nymphicus hollandicus): case report / Carcinoma indiferenciado de pâncreas em calopsitas (Nymphicus hollandicus): relato de caso

Undifferentiated carcinoma of the pancreas is a malignant neoplasm that is uncommon among domestic species, especially cockatiels (Nymphicus hollandicus), one of the most popular birds kept as a pet throughout the world. The aim of this study was to describe the occurrence of an undifferentiated carcinoma in the pancreas of a cockatiel. A bird, an adult male that died naturally with swelling in the abdominal region, was referred to necropsy. Macroscopic examination showed poor body condition, the coelomic cavity filled with liquid and a white mass attached to the pancreas and other smaller masses attached to the duodenum. Tissue samples and organs were harvested and fixed in 10% buffered formalin, then routinely processed for histopathology and stained with hematoxylin and eosin. Microscopic analysis demonstrated an epithelial neoplasia with a predominantly solid pattern, lymphatic invasion and involvement of the intestinal serous membrane. These findings indicate the occurrence of an undifferentiated pancreatic carcinoma in a cockatiel that was diagnosed by histopathology.(AU)

O carcinoma indiferenciado de pâncreas é uma neoplasia maligna, incomum entre as espécies domésticas, especialmente em calopsitas (Nymphicus hollandicus), uma das aves mais populares como animal de companhia no mundo. O objetivo deste trabalho foi descrever a ocorrência de carcinoma indiferenciado de pâncreas em Nymphicus hollandicus. Uma ave, macho adulto, com morte natural e com aumento de volume em região abdominal, foi encaminhada para necropsia. Ao exame macroscópico foram observados mau estado corporal, cavidade celômica repleta de líquido e massa esbranquiçada aderida ao pâncreas e outra menor aderida ao duodeno. Amostras de tecidos e órgãos foram colhidas em formol 10% tamponado, processadas rotineiramente para histopatologia e coradas por hematoxilina e eosina. Na microscopia foi observada neoplasia epitelial com padrão predominantemente sólido, com invasão linfática e implantação na serosa intestinal. Com esses achados, comprovou-se a ocorrência de carcinoma indiferenciado de pâncreas em Nymphicus hollandicus, o qual pode ser diagnosticado por meio de histopatologia.(AU)

Cathepsin B launches an apoptotic exit effort upon cell death-associated disruption of lysosomes.

The release of cathepsin proteases from disrupted lysosomes results in lethal cellular autodigestion. Lysosomal disruption-related cell death is highly variable, showing both apoptotic and necrotic outcomes. As the substrate spectrum of lysosomal proteases encompasses the apoptosis-regulating proteins of the Bcl-2 family, their degradation could influence the cell death outcome upon lysosomal disruption. We used Förster resonance energy transfer (FRET)-based biosensors to image the real-time degradation of the Bcl-2-family members, Bcl-xl, Bax and Bid, in living cells undergoing lysosomal lysis and identified an early chain of proteolytic events, initiated by the release of cathepsin B, which directs cells toward apoptosis. In this apoptotic exit strategy, cathepsin B's proteolytic activity results in apoptosis-inducing Bid and removes apoptosis-preventing Bcl-xl. Cathepsin B furthermore appears to degrade a cystein protease that would otherwise have eliminated apoptosis-supporting Bax, indirectly keeping cellular levels of the Bax protein up. The concerted effort of these three early events shifts the balance of cell fate away from necrosis and toward apoptosis.

Pneumotoxicosis in sheep caused by ingestion of trema micrantha.

Trema micrantha, a fast-growing tree distributed throughout the Americas, produces palatable leaves that have been associated with hepatic necrosis and acute death when consumed by livestock. This report describes fatal pulmonary disease of sheep triggered by consumption of Trema micrantha. Affected sheep had severe progressive dyspnea for a few days before death. Subcutaneous and mediastinal emphysema, reddened lungs, interalveolar septal thickening, and diffuse type II pneumocyte proliferation were the main pathological findings. After ingesting 77.5 and 102.5 g/kg (divided in 3 doses, at 30-day intervals) of T. micrantha leaves, 2 additional sheep developed the same condition. These findings indicate that T. micrantha toxicosis should be considered in the differential diagnosis of ovine respiratory disease.

The role of minor subpopulations within the leukemic blast compartment of AML patients at initial diagnosis in the development of relapse.

The majority of pediatric and younger adult (<60 years) AML patients achieve complete remission. However, 30-40% of patients relapse and display a dismal outcome. Recently we described a frequent instability of type I/II mutations between diagnosis and relapse. Here, we explored the hypothesis that these mutational shifts originate from clonal selection during treatment/disease progression. Subfractions of blasts from initial diagnosis samples were cell sorted and their mutational profiles were compared with those of the corresponding relapse samples of 7 CD34(+) AML patients. At diagnosis, subfractions of the CD45(dim)CD34(+)CD38(dim/-) compartment were heterogeneous in the distribution of mutations, when compared to the whole CD45(dim)CD34(+) blast compartment in 6 out of 7 patients. Moreover, within CD45(dim)CD34(+)CD38(dim/-) fraction of initial samples of 5 of these 6 AML patients, we found evidence for the presence of a minor, initially undetected subpopulation with a specific mutational profile that dominated the bulk of leukemic blasts at relapse. In conclusion, our findings lend support to the AML oligoclonality concept and provide molecular evidence for selection and expansion of a chemo-resistant subpopulation towards development of relapse. These results imply that early detection of pre-existing drug-resistant leukemic subpopulations is crucial for relapse prevention by proper timing of targeted treatment.

Inclusões intracitoplasmáticas hialinas na medular da adrenal de bovinos / Intracytoplasmic hyaline inclusions in adrenal medulla of bovine

Cytoplasmic inclusion bodies in adrenal medullary chromaffin cells have been described in various species including humans. These inclusions are believed to be related to certain infectious, toxic and neurodegenerative diseases. No reports concerning such adrenal inclusions have been described in bovines. Adrenal glands from twenty bovines were evaluated in a retrospective study. Seven of these exhibited inclusions - three cases of rabies, two cases of chronic suppurative bronchopneumonia, one case of chronic suppurative peritonitis, and one case of gangrenous mastitis. The inclusions were present in higher numbers especially in cases of rabies and also in one case of chronic suppurative bronchopneumonia. The inclusions were intracytoplasmic, eosinophilic, rounded, single or multiple, of various sizes, strongly stained by PAS and were present in higher numbers in the external layer of the adrenal medulla. The inclusions were negative when subjected to immunohistochemistry for detection of viral antigens in the cases of rabies. Although inclusion bodies were present in adrenal glands devoid of other histological alterations, they were more abundant in cases in which the adrenal gland had other alterations. The correlation between certain diseases and the development of inclusion bodies is not known, which highlights the importance of further studies on these inclusions in adrenal glands of bovines.

Mutant SOD1 detoxification mechanisms in intact single cells.

Mutant superoxide dismutase 1 (mtSOD1) causes dominantly inherited amyotrophic lateral sclerosis (ALS). The mechanism for mtSOD1 toxicity remains unknown. Two main hypotheses are the impairment of proteasomal function and chaperone depletion by misfolded mtSOD1. Here, we employed FRET/FLIM and biosensor imaging to quantitatively localize ubiquitination, as well as chaperone binding of mtSOD1, and to assess their effect on proteasomal and protein folding activities. We found large differences in ubiquitination and chaperone interaction levels for wild-type (wt) SOD1 versus mtSOD1 in intact single cells. Moreover, SOD1 ubiquitination levels differ between proteasomal structures and cytoplasmic material. Hsp70 binding and ubiquitination of wt and mtSOD1 species are highly correlated, demonstrating the coupled upregulation of both cellular detoxification mechanisms upon mtSOD1 expression. Biosensor imaging in single cells revealed that mtSOD1 expression alters cellular protein folding activity but not proteasomal function in the neuronal cell line examined. Our results provide the first cell-by-cell-analysis of SOD1 ubiquitination and chaperone interaction. Moreover, our study opens new methodological avenues for cell biological research on ALS.

All-solid-state lock-in imaging for wide-field fluorescence lifetime sensing.

Fluorescence Lifetime Imaging Microscopy (FLIM) is a powerful technique that is increasingly being used in the life sciences during the past decades. However, a broader application of FLIM requires more cost-effective and user-friendly solutions. We demonstrate the use of a simple CCD/CMOS lock-in imager for fluorescence lifetime detection. The SwissRanger SR-2 time-of-flight detector, originally developed for 3D vision, embeds all the functionalities required for FLIM in a compact system. The further development of this technology and its combination with light-emitting-and laser diodes could drive a wider spreading of thuse of FLIM including high-throughput applications.

Imaging biochemistry inside cells.

Proteins provide the building blocks for multicomponent molecular units, or pathways, from which higher cellular functions emerge. These units consist of either assemblies of physically interacting proteins or dispersed biochemical activities connected by rapidly diffusing second messengers, metabolic intermediates, ions or other proteins. It will probably remain within the realm of genetics to identify the ensemble of proteins that constitute these functional units and to establish the first-order connectivity. The dynamics of interactions within these protein machines can be assessed in living cells by the application of fluorescence spectroscopy on a microscopic level, using fluorescent proteins that are introduced within these functional units. Fluorescence is sensitive, specific and non-invasive, and the spectroscopic properties of a fluorescent probe can be analysed to obtain information on its molecular environment. The development and use of sensors based on the genetically encoded variants of green-fluorescent proteins has facilitated the observation of 'live' biochemistry on a microscopic level, with the advantage of preserving the cellular context of biochemical connectivity, compartmentalization and spatial organization. Protein activities and interactions can be imaged and localized within a single cell, allowing correlation with phenomena such as the cell cycle, migration and morphogenesis.

Imaging FRET between spectrally similar GFP molecules in single cells.

Fluorescence resonance energy transfer (FRET) detection in fusion constructs consisting of green fluorescent protein (GFP) variants linked by a sequence that changes conformation upon modification by enzymes or binding of ligands has enabled detection of physiological processes such as Ca(2+) ion release, and protease and kinase activity. Current FRET microscopy techniques are limited to the use of spectrally distinct GFPs such as blue or cyan donors in combination with green or yellow acceptors. The blue or cyan GFPs have the disadvantages of less brightness and of autofluorescence. Here a FRET imaging method is presented that circumvents the need for spectral separation of the GFPs by determination of the fluorescence lifetime of the combined donor/acceptor emission by fluorescence lifetime imaging microscopy (FLIM). This technique gives a sensitive, reproducible, and intrinsically calibrated FRET measurement that can be used with the spectrally similar and bright yellow and green fluorescent proteins (EYFP/EGFP), a pair previously unusable for FRET applications. We demonstrate the benefits of this approach in the analysis of single-cell signaling by monitoring caspase activity in individual cells during apoptosis.

Imaging protein-protein interactions by fluorescence resonance energy transfer (FRET) microscopy.

FRET microscopy enables the detection of different biochemical states of proteins in cells. The use of fluorescence in the detection of proteins, by chemical modification, by immunofluorescence, or by genetic encoding of a green fluorescent protein fusion protein, provides more information than just the location of the protein in the cell. The properties of the fluorophore can be exploited to extract information on protein-protein interactions. A straightforward, quantitative imaging approach is presented to measure FRET that is based on internal calibration by acceptor photobleaching.

Does electronic implementation of questionnaires used in asthma alter responses compared to paper implementation?

BACKGROUND: Electronic implementation of questionnaires has many advantages, but there may be concerns that it alters versions that were validated on paper. OBJECTIVE: To determine whether electronic implementation alters responses to the SF-36 and asthma quality of life questionnaire (AQLQ), compared to paper implementation. METHODS: Patients with asthma presenting to a pneumologist were asked for consent to participate. Each patient completed both forms of each questionnaire. The order of presentation was alternated sequentially, with the first patient completing the electronic version first. Each patient waited at least 2 hours between completions to minimize recollection of answers. For both the SF-36 and AQLQ, intraclass correlations coefficients were calculated to compare patients' scores, for each scale and overall, on the electronic and paper versions. RESULTS: Sixty-eight patients (mean age: 48 years, 50 females) of 311 contacted were enrolled. Overall intraclass correlation coefficients for the SF-36 and AQLQ were excellent (0.965 and 0.991 respectively). For paper versions, eight questions (AQLQ) and 24 (SF-36) were left blank and nine questions (SF-36) were answered incorrectly by patients selecting more than one answer. Electronic data for one patient could not be retrieved. CONCLUSION: Collecting SF-36 and AQLQ data electronically can decrease the number of spoiled responses without altering the results. Successful implementation depends on proper instruction of the respondent in the handling of the electronic instrument.

Quantitative imaging of lateral ErbB1 receptor signal propagation in the plasma membrane.

Evidence for a new signaling mechanism consisting of ligand-independent lateral propagation of receptor activation in the plasma membrane is presented. We visualized the phosphorylation of green fluorescent protein (GFP)-tagged ErbB1 (ErbB1-GFP) receptors in cells focally stimulated with epidermal growth factor (EGF) covalently attached to beads. This was achieved by quantitative imaging of protein reaction states in cells by fluorescence resonance energy transfer (FRET) with global analysis of fluorescence lifetime imaging microscopy (FLIM) data. The rapid and extensive propagation of receptor phosphorylation over the entire cell after focal stimulation demonstrates a signaling wave at the plasma membrane resulting in full activation of all receptors.

Fluorescence lifetime imaging of receptor tyrosine kinase activity in cells.

We report a highly specific fluorescence lifetime imaging microscopy (FLIM) method for monitoring epidermal growth factor receptor (EGFR) phosphorylation in cells based on fluorescence resonance energy transfer (FRET). EGFR phosphorylation was monitored using a green fluorescent protein (GFP)-tagged EGFR and Cy3-conjugated anti-phosphotyrosine antibodies. In this FRET-based imaging method, the information about phosphorylation is contained only in the (donor) GFP fluorescence lifetime and is independent of the antibody-derived (acceptor) fluorescence signal. A pixel-by-pixel reference lifetime of the donor GFP in the absence of FRET was acquired from the same cell after photobleaching of the acceptor. We show that this calibration, by acceptor photobleaching, works for the GFP-Cy3 donor-acceptor pair and allows the full quantitation of FRET efficiencies, and therefore the degree of exposed phosphotyrosines, at each pixel. The hallmark of EGFR stimulation is receptor dimerisation [1] [2] [3] [4] and concomitant activation of its intracellular tyrosine kinase domain [5] [6] [7]. Trans-autophosphorylation of the receptor [8] [9] on specific tyrosine residues couples the activated dimer to the intracellular signal transduction machinery as these phosphorylated residues serve as docking sites for adaptor and effector molecules containing Src homology 2 (SH2; reviewed in [10]) and phosphotyrosine-binding (PTB) [11] domains. The time-course and extent of EGFR phosphorylation are therefore important determinants of the underlying pathway and resulting cellular response. Our results strongly suggest that secondary proteins are recruited by activated receptors in endosomes, indicating that these are active compartments in signal transduction.

High-affinity binding of very-long-chain fatty acyl-CoA esters to the peroxisomal non-specific lipid-transfer protein (sterol carrier protein-2).

Binding of fluorescent fatty acids to bovine liver non-specific lipid-transfer protein (nsL-TP) was assessed by measuring fluorescence resonance energy transfer (FRET) between the single tryptophan residue of nsL-TP and the fluorophore. Upon addition of pyrene dodecanoic acid (Pyr-C12) and cis-parinaric acid to nsL-TP, FRET was observed indicating that these fatty acids were accommodated in the lipid binding site closely positioned to the tryptophan residue. Substantial binding was observed only when these fatty acids were presented in the monomeric form complexed to beta-cyclodextrin. As shown by time-resolved fluorescence measurements, translocation of Pyr-C12 from the Pyr-C12-beta-cyclodextrin complex to nsL-TP changed dramatically the direct molecular environment of the pyrene moiety: i.e. the fluorescence lifetime of the directly excited pyrene increased at least by 25% and a distinct rotational correlation time of 7 ns was observed. In order to evaluate the affinity of nsL-TP for intermediates of the beta-oxidation pathway, a binding assay was developed based on the ability of fatty acyl derivatives to displace Pyr-C12 from the lipid binding site as reflected by the reduction of FRET. Hexadecanoyl-CoA and 2-hexadecenoyl-CoA were found to bind readily to nsL-TP, whereas 3-hydroxyhexadecanoyl-CoA and 3-ketohexadecanoyl-CoA bound poorly. The highest affinities were observed for the very-long-chain fatty acyl-CoA esters (24:0-CoA, 26:0-CoA) and their enoyl derivatives (24:1-CoA, 26:1-CoA). Binding of non-esterified hexadecanoic acid and tetracosanoic acid (24:0) was negligible.

FRET microscopy demonstrates molecular association of non-specific lipid transfer protein (nsL-TP) with fatty acid oxidation enzymes in peroxisomes.

The fate of fluorescently labeled pre-nsL-TP (Cy3-pre-nsL-TP) microinjected into BALB/c 3T3 fibroblasts was investigated by confocal laser scanning microscopy. The protein exhibited a distinct punctate fluorescence pattern and colocalized to a high degree with the immunofluorescence pattern for the peroxisomal enzyme acyl-CoA oxidase. Proteolytic removal of the C-terminal leucine of the putative peroxisomal targeting sequence (AKL) resulted in a diffuse cytosolic fluorescence. These results indicate that microinjected Cy3-pre-nsL-TP is targeted to peroxisomes. The association of nsL-TP with peroxisomal enzymes was investigated in cells by measuring fluorescence resonance energy transfer (FRET) between the microinjected Cy3-pre-nsL-TP and Cy5-labeled antibodies against the peroxisomal enzymes acyl-CoA oxidase, 3-ketoacyl-CoA thiolase, bifunctional enzyme, PMP70 and catalase. The technique of photobleaching digital imaging microscopy (pbDIM), used to quantitate the FRET efficiency on a pixel-by-pixel basis, revealed a specific association of nsL-TP with acyl-CoA oxidase, 3-ketoacyl-CoA thiolase and bifunctional enzyme in the peroxisomes. These observations were corroborated by subjecting a peroxisomal matrix protein fraction to affinity chromatography on Sepharose-immobilized pre-nsL-TP. Acyl-CoA oxidase was retained. These studies provide strong evidence for a role of nsL-TP in the regulation of peroxisomal fatty acid beta-oxidation, e.g. by facilitating the presentation of substrates and/or stabilization of the enzymes.