CD4+ T cell response to the human acetylcholine receptor alpha subunit in myasthenia gravis. A study with synthetic peptides

The production of antinicotinic acetylcholine receptor (AcChR) antibodies in myasthenia gravis (MG) is modulated by specific Th (CD4+) lymphocytes that can recognize epitopes on the denatured AcChR alpha subunit. Thirty-two overlapping synthetic peptides corresponding to the complete sequence of human AcChR alpha subunit were used to investigate the anti-alpha subunit response of unselected lymphocytes and of CD8(+)-depleted, CD4(+)-enriched lymphocytes from the blood of nine MG patients and from four healthy controls. One subject was a newly diagnosed MG patient that was tested three times after the development of the disease. An anti-AcChR response of the CD4(+)-enriched cells was present that could be detected only after removal of the CD8+ population and that seems to be related to the clinical conditions of the patient. The high basal rate of the cell proliferation of the unselected unstimulated blood lymphocytes and the normal basal rate observed for the CD8(+)-depleted population suggested the presence of activated CD8+ cells. The study of surface markers of the T cells confirmed the existence of activated CD8+ and CD4+ cells in numbers correlated with the severity of the disease and the results of the in vitro response of the T cells. The anti-AcChR activity of the CD4+ cells in MG may be a useful marker of the activity of the disease and it seems to be influenced by activated CD8+ cells present in the patients' blood.     

Body size and fecundity of Juxtafabia muliniarum (Brachyura: Pinnotheridae) associated with Saccostrea palmula (Bivalvia: Ostreidae), Costa Rica

Size and fecundity observations of pea crab (Juxtafabia muliniarum) from the paleal cavity of the oyster Saccostrea palmula were made from May 1998 to May 1999. Infestation frequency was 18.52% in a sample of 540 oysters. Of 136 pea crabs, 36% were couples, 60% were single females and 4% were single males. The mean caparace length of J. muliniarum was 5.6 +/- 0.74 mm (range 4.0 to 7.6 mm) for females and 2.71 +/- 0.60 mm (range 1.6 to 4.0 mm) for males. The mean weight was 0.180 +/- 0.084 g (range 0.06 to 0.4 g) for females and 0.011 +/- 0.003 g (range 0.01 to 0.02 g) for males. Ovigerous females (43.75% of all females) were found in all months. The caparace length-fecundity relationship was F = 3904.6 Ln (Lc)--4651.1. The caparace length-weight relationship was P = 6 x 10(-4) Lc3.2122. The mean sex-ratio was 1.0 male: 2.4 females. Saccostrea palmula infected only by females was the dominant group (60.78%). This mollusk is a new host record for the crab.     

Selfie and the City: A World-Wide,Large, and Ecologically Valid Database Reveals a Two-Pronged Side Bias in Na?ve Self-Portraits

Self-portraits are more likely to show the artist’s right than left cheek. This phenomenon may have a psychobiological basis: Self-portraitists often copy their subject from mirrors and, if they prefer to present their left cheek (more expressive due to right-lateralization of emotions) to the mirror, this would result in a right-cheek bias in the painting. We tested this hypothesis using SelfieCity (3200 selfies posted on Instagram from December 4 through 12, 2013 from New York, Sao Paulo, Berlin, Moskow, and Bangkok), which includes two selfie-taking styles: a “standard” (photograph of selfie-taker) and a “mirror” (photograph of mirror reflection of selfie-taker) style. We show that the first style reveals a left cheek bias, whereas the second reveals a right cheek bias. Thus side biases observed in a world-wide, large, and ecologically valid database of naïve self-portraits provide strong support for a role of psychobiological factors in the artistic composition of self-portraits.     

(⁹⁹m)Tc-bisphosphonate-iron oxide nanoparticle conjugates for dual-modality biomedical imaging

The combination of radionuclide-based imaging modalities such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) with magnetic resonance imaging (MRI) is likely to become the next generation of clinical scanners. Hence, there is a growing interest in the development of SPECT- and PET-MRI agents. To this end, we report a new class of dual-modality imaging agents based on the conjugation of radiolabeled bisphosphonates (BP) directly to the surface of superparamagnetic iron oxide (SPIO) nanoparticles. We demonstrate the high potential of BP-iron oxide conjugation using (??m)Tc-dipicolylamine(DPA)-alendronate, a BP-SPECT agent, and Endorem/Feridex, a liver MRI contrast agent based on SPIO. The labeling of SPIOs with (??m)Tc-DPA-alendronate can be performed in one step at room temperature if the SPIO is not coated with an organic polymer. Heating is needed if the nanoparticles are coated, as long as the coating is weakly bound as in the case of dextran in Endorem. The size of the radiolabeled Endorem (??m)Tc-DPA-ale-Endorem) was characterized by TEM (5 nm, Fe?O? core) and DLS (106 ± 60 nm, Fe?O? core + dextran). EDX, Dittmer-Lester, and radiolabeling studies demonstrate that the BP is bound to the nanoparticles and that it binds to the Fe?O? cores of Endorem, and not its dextran coating. The bimodal imaging capabilities and excellent stability of these nanoparticles were confirmed using MRI and nanoSPECT-CT imaging, showing that (??m)Tc and Endorem co-localize in the liver and spleen In Vivo, as expected for particles of the composition and size of (??m)Tc-DPA-ale-Endorem. To the best of our knowledge, this is the first example of radiolabeling SPIOs with BP conjugates and the first example of radiolabeling SPIO nanoparticles directly onto the surface of the iron oxide core, and not its coating. This work lays down the basis for a new generation of SPECT/PET-MR imaging agents in which the BP group could be used to attach functionality to provide targeting, stealth/stability, and radionuclides to Fe?O? nanoparticles using very simple methodology readily amenable to GMP.     

Use of synthetic peptides to establish anti-human acetylcholine receptor CD4+ cell lines from myasthenia gravis patients

Acetylcholine receptor-(AcChR) specific T cell lines were propagated from the PBL of six myasthenia gravis (MG) patients by the use of a pool of synthetic peptides (alpha-pool) corresponding to the complete sequence of the alpha-subunit of the human AcChR. All the lines had CD4+ phenotype and strongly recognized the alpha-pool. Four lines cross-reacted with native Torpedo AcChR. Five lines showed, at certain stages of their propagation, some degree of reactivity to autologous or DR-matched APC. One of the CD4+ T lines was challenged with each one of the peptides present in the alpha-pool. Several peptides, corresponding to the sequence segments 48-67, 101-120, 304-322, 320-337, and 419-437 of the human alpha-subunit were recognized, indicating that different epitopes and multiple T cell clones are involved in the recognition of the autoantigen in MG. Human AcChR-specific CD4+ T cell lines will be useful to identify the repertoire of epitopes recognized by the autoreactive Th cells in MG, to investigate the TCR genes utilized by autoreactive Th cells and to develop specific immunosuppressive treatments using anti-T cell vaccination.     

How Reliable Are Current Data for Assessing the Actual Prevalence of Chronic Obstructive Pulmonary Disease?

Background

Estimating COPD occurrence is perceived by the scientific community as a matter of increasing interest because of the worldwide diffusion of the disease. We aimed to estimate COPD prevalence by using administrative databases from a city in central Italy for 2002–2006, improving both the sensitivity and the reliability of the estimate.

Methods

Multiple sources were used, integrating the hospital discharge register (HDR), clinical charts, spirometry and the cause-specific mortality register (CMR) in a longitudinal algorithm, to reduce underestimation of COPD prevalence. Prevalence was also estimated on the basis of COPD cases confirmed through spirometry, to correct misclassification. Estimating such prevalence relied on using coefficients of validation, derived as the positive predictive value (PPV) for being an actual COPD case from clinical and spirometric data at the Institute of Clinical Physiology of the National Research Council.

Results

We found that sensitivity of COPD prevalence increased by 37%. The highest estimate (4.43 per 100 residents) was observed in the 5-year period, using a 3-year longitudinal approach and combined data from three sources. We found that 17% of COPD cases were misclassified. The above estimate of COPD prevalence decreased (3.66 per 100 residents) when coefficients of validation were applied. The PPV was 80% for the HDR, 82% for clinical diagnoses and 91% for the CMR.

Conclusions

Adjusting the COPD prevalence for both underestimation and misclassification of the cases makes administrative data more reliable for epidemiological purposes.     

Generation of tissue-specific and promiscuous HLA ligand databases using DNA microarrays and virtual HLA class II matrices.

Most pockets in the human leukocyte antigen-group DR (HLA-DR) groove are shaped by clusters of polymorphic residues and, thus, have distinct chemical and size characteristics in different HLA-DR alleles. Each HLA-DR pocket can be characterized by "pocket profiles," a quantitative representation of the interaction of all natural amino acid residues with a given pocket. In this report we demonstrate that pocket profiles are nearly independent of the remaining HLA-DR cleft. A small database of profiles was sufficient to generate a large number of HLA-DR matrices, representing the majority of human HLA-DR peptide-binding specificity. These virtual matrices were incorporated in software (TEPITOPE) capable of predicting promiscuous HLA class II ligands. This software, in combination with DNA microarray technology, has provided a new tool for the generation of comprehensive databases of candidate promiscuous T-cell epitopes in human disease tissues. First, DNA microarrays are used to reveal genes that are specifically expressed or upregulated in disease tissues. Second, the prediction software enables the scanning of these genes for promiscuous HLA-DR binding sites. In an example, we demonstrate that starting from nearly 20,000 genes, a database of candidate colon cancer-specific and promiscuous T-cell epitopes could be fully populated within a matter of days. Our approach has implications for the development of epitope-based vaccines.     

Distribution and abundance of Caiman crocodilus in the Caño Negro National Wild Life Refuge, Costa Rica

The distribution and abundance of a population of Caiman crocodilus fuscus were estimated by monthly counting of eye-shines at night, from February 1999 to March 2000 in six transects of Río Frío in the Ca?o Negro National Refuge (RNVSCN), Northern Costa Rica. March was the month with the greatest abundance of caimans observed. The visible fraction of the population (PV2 index) fluctuated between 42.59% to 54.71% during the wet season and 35.49% to 53.93% in the dry season. The transects of river with greater abundance of caimans were Terrón-Sabogal and Sabogal-Playuela. Significant differences were determined in the abundance of caimans between transects, except the transects Entrada San Sebastían-Las Cubas and Las Cubas-Entrada Ca?o Los Patos and Entrada Ca?o Los Patos-Terrón and Boca Sabogal-Playuela. The population of estimated brown caiman in this study was 2283.48 +/- 313.5. The statistical analysis by seasons did not show significant differences in the number of caimans observed. Estimated mean number of caimans per km of river was 74.36/km for 30.7 km of habitat. The results of this study indicated that the fluctuation in population density during the seasons is attributable to local movements.     

Composition, growth and conditionindex for a population of Poecilia reticulata (Pisces: Poeciliidae), in a pond in Heredia, Costa Rica

A pond population of Poecilia reticulata was studied in Santo Domingo, Heredia, Costa Rica, between September and November of 1998. The sex ratio was 1:0.49 (males:females). The mean total length was 34.43 +/- 7.26 mm for females, 23.50 +/- 2.24 mm for males and 12.27 +/- 3.41 mm for juveniles. The mean total weight was 0.69 +/- 0.48 g for females: and 0.16 +/- 0.05 g for males and 0.026 +/- 0.027 g for juveniles. The total length-weight relationship for the total population was P= 6 x 10(-5) Lt 3.3272 (r2 = 0.9613). The condition index equation was K = 25.755 e(0.004Lt) (r2 = 0.8925) for females and K = 26.767 e(0.003Lt) (r2 = 0.907) for males. The mean condition index was 31.29 +/- 0.55% for females and 28.52 +/- 0.19% for males. Both sexes reached the sexual maturity when the males and females overcame the 20.00 mm and 23.5 mm of Lt respectively.