bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of glycophorin A and glycophorin B on normal human RBCs by flow cytometry
Authors: Isla Natalia G. de , Riquelme Bibiana D. , Rasia Rodolfo J. , Valverde Juana R. , Stoltz Jean F.
Published: July 2003

BACKGROUND: The quantification of antigens and proteins on RBCs has been achieved by different approaches. Flow cytometry allows the results of the earliest studies to be to reappraised because it offers the possibility of measuring the immunofluorescence intensity of single cells and integrating the individual data of a large number of cells within a very short time.

STUDY DESIGN AND METHODS: Flow cytometry was used in this work to analyze the binding of four MoAbs to glycophorin A (GPA) and glycophorin B (GPB). RBCs in their native state (nonfixed) were utilized. To avoid the agglutination problem, cells were disaggregated before measurements, dates were taken on 20,000 events on the single‐cell region, and the fluorescence intensity of the principal peak present in the fluorescence histograms was used for the analysis. The quantification of sites per RBC was estimated by applying the Langmuir adhesion model.

RESULTS: The numbers of GPA and GPB sites obtained for samples from healthy donors were similar to those found in the literature (1.86‐4.9) × 105 and (0.48‐1.61) × 105 for GPA and (0.21‐1.14) × 105 and (0.47‐0.88) × 105 for GPB. Differences between antibodies were found that depend on the binding site of each one.

CONCLUSION: A simple method to quantify antigen sites on RBCs was developed. It could be applied whenever one antibody is assumed to bind exactly one antigen.
Molecular genetic analysis for the Ae1 and A3 alleles
Authors: Sun Chien‐Feng , Yu Lung‐Chih , Chen Ing‐Ping , Chou Ding‐Lun , Twu Yuh‐Ching , Wang Wei‐Ting , Lin Marie
Published: July 2003

BACKGROUND: In addition to the common ABO phenotypes, numerous phenotypes with a weak expression of the A or B antigens on RBCs have been found. This study describes the molecular genetic analysis of the Ael and the A3 phenotypes.

STUDY DESIGN AND METHODS: The seven‐exon regions of the ABO genes of Ael and A3B individuals were amplified by PCR and cloned, and the sequences of the exons and their adjacent splice sites were analyzed. Samples from 30 randomly selected A1 individuals were also assessed.

RESULTS: The A gene with wild‐type coding sequence was demonstrated in the Ael propositus, but all the six unrelated Taiwanese people with the Ael or AelB phenotype were shown to possess an A allele with the G→A mutation at the +5 position of intron 6 (IVS6+5G→A). RT‐PCR analysis showed that the complete A transcript structure was absent in the Ael RNA samples. The A3B individual possessed an A gene with an 838C→T missense mutation.

CONCLUSION: The results suggest an association of the Ael*IVS6+5G→A allele with the Ael phenotype in Taiwanese people. The mechanism defining how the Ael*IVS6+5G→A allele leads to the Ael phenotype awaits elucidation.
Effects of Amiodarone and Dronedarone on Voltage‐Dependent Sodium Current in Human Cardiomyocytes
Authors: Lalevée Nathalie , Barrère‐lemaire Stéphanie , Gautier Patrick , Nargeot Joël , Richard Sylvain
Published: July 2003

Introduction: Amiodarone (AM) is a highly effective antiarrhythmic agent used in the management of both atrial and ventricular arrhythmias. Its noniodinated analogue dronedarone (SR) may have fewer side effects than AM. In this study, we compared the effects of AM and SR on the sodium current INa in human atrial myocytes.

Methods and Results: INa was studied with the whole‐cell, patch clamp technique. Both AM and SR induced a dose‐dependent inhibition of INa recorded at −40 mV from a holding potential of −100 mV. AM inhibited INa by 41%± 11% (n = 4) at 3 μM, and by 80%± 7% (n = 5) at 30 μM. SR produced more potent block, inhibiting INa significantly at only 0.3 μM (23%± 10%, n = 4) and completely (97%± 4%, n = 4) at 3 μM. Both AM and SR had only moderate effects on voltage‐dependent properties of INa (current‐voltage relationship, availability for activation) and had no effect on the current decay kinetics.

Conclusion: Both AM and SR inhibit INa significantly in single human atrial cells, showing that the two drugs have Class I antiarrhythmic properties. The acute effects of SR are more potent than those of AM. The study supports the idea that the iodinated form of the molecule has no part in the acute effect of AM on Na+ channels. (J Cardiovasc Electrophysiol, Vol. 14, pp. 885‐890, August 2003)
Evidence of Specialized Conduction Cells in Human Pulmonary Veins of Patients with Atrial Fibrillation
Authors: Perez‐Lugones Alejandro , McMahon James T. , Ratliff Norman B. , Saliba Walid I. , Schweikert Robert A. , Marrouche Nassir F. , Saad Eduardo B. , Navia José L. , McCarthy Patrick M. , Tchou Patrick , Gillinov A. Marc , Natale Andrea
Published: July 2003

Introduction: Depolarizations similar to those from the sinus node have been documented from the pulmonary veins after isolation procedures. We assessed the hypothesis that sinus node‐like tissue is present in the pulmonary veins of humans.

Methods and Results: Pulmonary vein tissue was obtained from five autopsies (four individuals with a history of atrial fibrillation and one without a history of atrial arrhythmias) and five transplant heart donors. Autopsy veins were fixed in formaldehyde and processed for light microscopy to identify areas having possible conductive‐like tissue. Areas requiring additional study were extracted from paraffin blocks and reprocessed for electron microscopy. Donor specimens were fixed in formaldehyde for histologic sections and glutaraldehyde for electron microscopy. Myocardial cells with pale cytoplasm were identified by light microscopy in 4 of the 5 autopsy subjects. Electron microscopy confirmed the presence of P cells, transitional cells, and Purkinje cells in the pulmonary veins of these cases.

Conclusion: Our report is the first to show the presence of P cells, transitional cells, and Purkinje cells in human pulmonary veins. Whether these cells are relevant in the genesis of atrial fibrillation requires further study. (J Cardiovasc Electrophysiol, Vol. 14, pp. 803‐809, August 2003)
Circadian Profile of Cardiac Autonomic Nervous Modulation in Healthy Subjects:
Authors: Bonnemeier Hendrik , Wiegand Uwe K.H. , Brandes Axel , Kluge Nina , Katus Hugo A. , Richardt Gert , Potratz Jürgen
Published: July 2003

Introduction: Although heart rate variability (HRV) has been established as a tool to study cardiac autonomic activity, almost no data are available on the circadian patterns of HRV in healthy subjects aged 20 to 70 years.

Methods and Results: We investigated 166 healthy volunteers (81 women and 85 men; age 42 ± 15 years, range 20–70) without evidence of cardiac disease. Time‐domain HRV parameters were determined from 24‐hour Holter monitoring and calculated as hourly mean values and mean 24‐hour values. All volunteers were fully mobile, awoke around 7 A.M., and had 6 to 8 hours of sleep. Circadian profiles of vagus‐associated HRV parameters revealed a marked day‐night pattern, with a peak at nighttime and a plateau at daytime. The characteristic nocturnal peak and the day‐night amplitude diminished with aging by decade. Estimates of overall HRV (geometric triangular index [TI], SD of NN intervals [SDNN]) and long‐term components of HRV (SD of the averages of NN intervals for all 5‐min segments [SDANN]) were low at nighttime and increased in the morning hours. There was a significant decline of 24‐hour values of all HRV parameters (P < 0.001) and a strong negative correlation (P < 0.001) with increasing age. Mean 24‐hour RR interval (P < 0.001), SDNN, mean SD of NN intervals for all 5‐minute intervals (SDNNi), and SDANN (all P < 0.01) were significantly higher in men. Younger men also exhibited significantly higher values for vagus‐associated parameters (root mean square successive difference [rMSSD], P < 0.05; SDNNi, P < 0.01); however, gender differences diminished with increasing age.

Conclusion: Normal aging is associated with a constant decline of cardiac vagal modulation due to a significant decrease of nocturnal parasympathetic activity. The significant gender‐related difference of HRV decreases with aging. These findings emphasize the need to determine age‐, gender‐, and nycthemeral‐dependent normal ranges for HRV assessment. (J Cardiovasc Electrophysiol, Vol. 14, pp. 791‐799, August 2003)
Psychosocial Aspects of Patient‐Activated Atrial Defibrillation
Authors: Mitchell Andrew R.J. , Spurrell Philip A.R. , Boodhoo Lana , Sulke Neil
Published: July 2003

Introduction: The atrial defibrillator empowers patients to cardiovert themselves from atrial arrhythmias at a time that is socially and physically acceptable, thereby preventing hospitalization. The long‐term psychosocial effects of repeated use of the patient‐activated atrial defibrillator at home are unknown.

Methods and Results: Eighteen patients underwent placement of the Jewel AF atrial defibrillator for persistent atrial fibrillation only. All patients performed manually activated cardioversions at home under self‐administered sedation. Automatic shock therapies were disabled. Hospital Anxiety and Depression Scale and Multidimensional Health Locus of Control questionnaires were obtained before implant. All patients completed questionnaires 1 year after device implant and at long‐term follow‐up. The spouse or partner of each patient was interviewed to identify positive and negative aspects of manual cardioversion at home. The baseline patient scores for both anxiety (5.7 ± 2.7) and depression (3.4 ± 2.3) fell within the predefined range of normality. At 1 year, there was no significant change in anxiety (4.9 ± 3.7, P = 0.39) or depression (2.4 ± 1.8, P = 0.06). At long‐term follow‐up (mean 28 months), a total of 377 patient‐activated cardioversions were performed out of hospital (median 15 per patient). Scores for anxiety (6.0 ± 4.0, P = 0.70) and depression (3.2 ± 2.5, P = 0.68) remained unchanged.

Conclusion: During long‐term follow‐up, patient‐activated cardioversion using the atrial defibrillator was not associated with increased anxiety or depression. The procedure was well tolerated by patients and their partners, offering an acceptable treatment option for patients with recurrent persistent atrial fibrillation. (J Cardiovasc Electrophysiol, Vol. 14, pp. 812‐816, August 2003)
Biphasic versus Monophasic Cardioversion in Shock‐Resistant Atrial Fibrillation:
Authors: Khaykin Yaariv , Newman David , Kowalewski Marnie , Korley Victoria , Dorian Paul
Published: July 2003

Introduction: Cardioversion of atrial fibrillation using monophasic transthoracic shocks occasionally is ineffective. Biphasic cardioversion requires less energy than monophasic cardioversion, but its efficacy in shock‐resistant atrial fibrillation is unknown. Thus, we compared the efficacy of cardioversion using biphasic versus monophasic waveform shocks in patients with atrial fibrillation previously refractory to monophasic cardioversion.

Methods and Results: Fifty‐six patients with prior failed monophasic cardioversion were randomized to either a 360‐J monophasic damped sinusoidal shock or biphasic truncated exponential shocks at 150 J, followed by 200 J and then 360 J, if necessary. If either waveform failed, patients were crossed over to the other waveform. The primary endpoint was defined as the proportion of patients achieving sinus rhythm following initial randomized therapy. Stepwise multivariate logistic regression examined independent predictors of shock success, including patient age, sex, left atrial diameter, body mass index, drug therapy, and waveform. Twenty‐eight patients were randomized to the biphasic shocks and 28 to the monophasic shocks. Sinus rhythm was restored in 61% of patients with biphasic versus 18% with monophasic shocks (P = 0.001). Seventy‐eight percent success was achieved in patients who crossed over to the biphasic shock after failing monophasic cardioversion, whereas only 33% were successfully cardioverted with a monophasic shock after crossover from biphasic shock (P = 0.02). Overall, 69% of patients who received a biphasic shock at any point in the protocol were cardioverted successfully, compared to 21% with the monophasic shock (P < 0.0001). The type of shock was the strongest predictor of shock success (P = 0.0001) in multivariate logistic regression.

Conclusion: An ascending sequence of 150‐, 200‐, and 360‐J transthoracic biphasic cardioversion shocks are successful more often than a single 360‐J monophasic shock. Thus, biphasic shocks should be the recommended configuration of choice for all cardioversions. (J Cardiovasc Electrophysiol, Vol. 14, pp. 868‐872, August 2003)
Mode switching in dual chamber pacemakers
Authors: Marshall H.J. , Kay G.N. , Hess M. , Plumb V.J. , Bubien R.S. , Hummel J. , Dawson D. , Markewitz T. , Gammage M.D.
Published: July 2003

Aims

Various mode-switching algorithms are available with different tachyarrhythmia detection criteria to be satisfied to initiate mode-switching. This study evaluated three different mode-switching algorithms in patients with paroxysmal atrial fibrillation.

Methods and Results

Seventeen patients completed the study. Three mode-switching algorithms were downloaded as software into the pacemaker, each for 1 month in a single-blind, randomized sequence. The criteria to initiate mode-switching were: mean atrial rate (‘standard’), ‘4-of-7’ or ‘1-of-1’ atrial intervals to exceed the atrial detection rate. Symptoms for each were measured using the Symptom Checklist–Frequency and Severity index.

The median number of mode-switch episodes increased from 20 for ‘standard’ to 39 for ‘4-of-7’ (P=0·029 vs ‘standard’) and 103 for ‘1-of-1’ (P=0·0012 vs ‘standard’) onset criteria. Median duration of episodes decreased from 2·5 min with ‘standard’ to 1·4 min with ‘4-of-7’ and 0·4 min with ‘1-of-1’ onset criteria. Frequency of symptoms was lower using ‘4-of-7’ (18·2±12·0 vs 23±12·0, P=0·08) or ‘1-of-1’ (20·4±12·4 vs 23±12·0, P=0·07) than ‘standard’ onset criteria. Severity of arrhythmia tended to be less with either ‘4-of-7’ (16±10·4 vs 19·1±19·4, P=0·12) or ‘1-of-1’ (17·5±10·3 vs 19·1±9·4, P=0·18) than with ‘standard’ onset criteria.

Conclusions

The more sensitive onset criteria for detection of atrial tachyarrhythmias were associated with lower frequency and severity of symptoms.
SAFE PACE 2: Syncope and Falls in the Elderly — Pacing and Carotid Sinus Evaluation
Authors: Kenny R. A.
Published: July 2003

SAFE PACE is a multicentre randomized controlled trial to assess the efficacy of dual-chamber pacing in older patients with carotid sinus hypersensitivity and recurrent un-explained falls. Patients are eligible if they have had two or more unexplained falls (± up to one syncope) and if they have a cardio-inhibitory response (>3 s asystole) to carotid sinus massage. Patients will be randomized to receive either a Medtronic Kappa 700(Europe)/Kappa 400(North America) pacemaker or an implantable loop recorder (ILR)(control group). Patients will be required to complete weekly fall diaries. The primary outcome measure is the number of patients who fall in the 24-month follow-up period. Recruitment began in October 1998 and continues for 12 months; the follow-up is for 24 months.
The Genus Artemisia and its Allies: Phylogeny of the Subtribe Artemisiinae (Asteraceae, Anthemideae) Based on Nucleotide Sequences of Nuclear Ribosomal DNA Internal Transcribed Spacers (ITS)
Authors: Vallès J. , Torrell M. , Garnatje T. , Garcia‐Jacas N. , Vilatersana R. , Susanna A.
Published: July 2003

Abstract: Sequences of the internal transcribed spacers (ITS1 and ITS2) of nuclear ribosomal DNA were analysed for 44 Artemisia species (46 populations) representing all the five classical subgenera and the geographical range of the genus, 11 species from 10 genera closely related to Artemisia, and six outgroup species from five other genera of the Anthemideae. The results definitely support the monophyly of the genus Artemisia in its broadest sense (including some taxa segregated as independent genera, like Oligosporus and Seriphidium). Eight main clades are established in this molecular phylogeny within Artemisia; they agree in part with the classical subdivision of the genus, but they also suggest that some infrageneric groups must be redefined, especially the subgenus Artemisia. The subgenera Tridentatae and Seriphidium are independent from each other. Some of the satellite genera are clearly placed within Artemisia (Artemisiastrum, Filifolium, Mausolea, Picrothamnus, Sphaeromeria, Turaniphytum), whereas some others fall outside the large clade formed by this genus (Brachanthemum, Elachanthemum, Hippolytia, Kaschgaria). Our results, correlated to other data such as pollen morphology, allow us to conclude that the subtribe Artemisiinae as currently defined is a very heterogeneous group. Affinities of the largest genus of the subtribe and tribe, Artemisia, and of other genera of the subtribe to some genera from other subtribes of the Anthemideae strongly suggest that subtribe Artemisiinae needs a deep revision and redefinition. Phylogenetic utility of region trnL‐F of the plastid DNA in the genus Artemisia and allies was also evaluated: sequences of the trnL‐F region in Artemisia do not provide phylogenetic information.
The Impact of Different Long‐Term Storage Conditions on the Viability of Lichen‐Forming Ascomycetes and their Green Algal Photobiont, Trebouxia spp.
Authors: Honegger R.
Published: July 2003

Abstract: Lichen‐forming ascomycetes and their green algal photobionts completely die off within approximately 3 years of storage at room temperature. Macroscopically this is recognizable as a colour change, the green shades of the chlorophylls being lost. In fluorescent light microscopy preparations an increase in fungal autofluorescence and a significant decrease in chlorophyll autofluorescence in the Trebouxia cells was observed. In transmission electron microscopy preparations of Xanthoria parietina and its green algal photobiont, Trebouxia arboricola, the fungal membrane systems were found to be largely broken down whereas the shrivelled algal protoplast failed to rehydrate after storage at room temperature. When stored in the desiccated state at ‐ 20 °C, both partners of the symbiosis stayed fully viable for up to 13 years, their colouration and chlorophyll fluorescence being unchanged. Viability was measured as ascospore ejection and germination rates in Xanthoria parietina, soredium germination rates in Xanthoria fallax, Hypogymnia physodes and Parmelia sulcata, and autospore formation rate in Trebouxia cells (green algal photobiont), which had been isolated from the thalli after rehydration. Thallus fragments of Xanthoria parietina were shown to grow normally after one week of storage in LN2 without any cryoprotectant. In the desiccated state deep‐frozen samples can be repeatedly brought to room temperature and back to ‐ 20 °C without any loss of viability. Cryopreservation is therefore a suitable mode of long‐term storage of viable lichen thalli for experimental studies or transplant experiments.
Characterisation of Simple In Vitro Cultures of Striga hermonthica Suitable for Metabolic Studies
Authors: Rousset A. , Simier P. , Fer A.
Published: July 2003

Abstract: The aim of this study is to develop simplified models for standardised screenings of xenobiotics, especially targeted against mannitol production, to control the harmful parasite, S. hermonthica. Chlorophyllous protoplasts and calli were produced from the young leaves of the parasite. Best yield from protoplast isolation was obtained when leaf segments were incubated at 30 °C, in the light, under shaking in an enzyme cocktail containing 2 % cellulase Onozuka R10, 0.1 % Pectolyase and sorbitol 1 M as the osmoticum. Oxygen exchange measurements, as well as labelling experiments with 14C‐bicarbonate, emphasised a significant decrease in photosynthetic capacity of protoplasts, mannitol remaining, however, a major primary product of photosynthesis. Initiation of cell cultures was unsuccessful and instability of protoplasts prevents their standardised utilisation for herbicide screening. In contrast, globular calli produced first on MS medium containing 0.5 mg L‐1 NAA, 2.5 mg L‐1 BAP and 2 % sucrose were stable for two years, after monthly subculturing on fresh medium. Sucrose substitution by mannose in the medium did not change kinetic growth and stability. Potential autotrophy was lost for calli by increasing exogenous sugar level. Biochemical analyses and labelling experiments with 14C‐bicarbonate or 14C‐sucrose or ‐mannose showed that carbon partitioning is modified in calli, in comparison with young leaves or protoplasts, sucrose or mannose accumulation being favoured in sucrose‐ or mannose‐fed calli, respectively. However, carbon flow towards mannitol was more marked in calli growing on high mannose medium. Stability and preservation of an active mannitol biosynthetic pathway allows planning of xenobiotic assays with calli as a simplified model for Striga hermonthica.
Multiple Effects of Chromate on Spirodela polyrhiza: Electron Microscopy and Biochemical Investigations
Authors: Appenroth K.‐J. , Keresztes Á. , Sárvári É. , Jaglarz A. , Fischer W.
Published: July 2003

Abstract: Growth rates of S. polyrhiza were reduced by chromate concentrations higher than 50 μM. Analysis of plant cells by transmission electron microscopy revealed the accumulation of starch grains in the chloroplasts following the application of chromate at low concentrations or for short periods (100 μM for 2 days or 500 μM for 1 day). Increasing the chromate concentration (1000 μM for 1 day) or extending the period (100 μM for 4 days) resulted in the disappearance of most of the starch grains and the extensive formation of plastoglobuli. These results were confirmed by chemical analysis of the starch content. It has been suggested that this transient accumulation of starch was caused, first, by inhibition of the export of carbohydrates out of the plastids, and then by inhibition of photosynthesis. Chromate decreased the chlorophyll content and the chlorophyll a/b ratio. The quantitative analysis of the chlorophyll protein complexes showed that the photosystem II (core complex as well as connecting antenna) was more sensitive to chromate treatment than photosystem I and the peripheral light‐harvesting complex of photosystem II. This explains the previous results on time‐resolved chlorophyll a fluorescence (Appenroth et al. Environ. Pollut. [2001] 115, 49 ‐ 64). Photosynthesis is clearly an important target of chromate toxicity. Electron microscopic analysis showed damage to several membrane systems, such as that of thylakoids, chloroplast envelope, plasmalemma and, at higher concentrations, that of tonoplast and mitochondria. Thus, the membrane system is another target of chromate toxicity.
The structural basis for giant enhancement enabling single-molecule Raman scattering
Authors: Wang Zhenjia , Pan Shanlin , Krauss Todd D. , Du Hui , Rothberg Lewis J.
Published: July 2003

We find that giant surface-enhanced Raman scattering for adsorbates on
silver surfaces is present only on surfaces that exhibit self-similar fractal
topology as inferred from atomic force microscopy. The fractal character
results in localizing the energy of incident photons to volumes of a few
nanometers on a side, millions of times smaller than the diffraction limit.
Consistent with this finding, we have found an enhancement in spontaneous
Raman cross section of >13 orders of magnitude for adsorbates on silver
surfaces demonstrated to be fractal. The location of “hot spots”
on the fractal surfaces is found to be hypersensitive to incident wavelength
and polarization even though the observed Raman scattering is strictly linear
in incident intensity. These observations are consistent with localization of
the photon energy facilitated by the disordered nature of fractal organization
through interference between the incident wave and scattered radiation from
silver nanoparticle surface plasmons. We also present a surface preparation
method that consistently produces fractal topologies that support
single-molecule Raman scattering.
Functional and comparative genomic analyses of an operon involved in fructooligosaccharide utilization by
Lactobacillus acidophilus
Authors: Barrangou Rodolphe , Altermann Eric , Hutkins Robert , Cano Raul , Klaenhammer Todd R.
Published: July 2003

Lactobacillus acidophilus
is a probiotic organism that displays
the ability to use prebiotic compounds such as fructooligosaccharides (FOS),
which stimulate the growth of beneficial commensals in the gastrointestinal
tract. However, little is known about the mechanisms and genes involved in FOS
utilization by
Lactobacillus
species. Analysis of the
L.
acidophilus
NCFM genome revealed an
msm
locus composed of a
transcriptional regulator of the
Lac
I family, a four-component
ATP-binding cassette (ABC) transport system, a fructosidase, and a sucrose
phosphorylase. Transcriptional analysis of this operon demonstrated that gene
expression was induced by sucrose and FOS but not by glucose or fructose,
suggesting some specificity for nonreadily fermentable sugars. Additionally,
expression was repressed by glucose but not by fructose, suggesting catabolite
repression via two
cre
-like sequences identified in the
promoter–operator region. Insertional inactivation of the genes encoding
the ABC transporter substrate-binding protein and the fructosidase reduced the
ability of the mutants to grow on FOS. Comparative analysis of gene
architecture within this cluster revealed a high degree of synteny with
operons in
Streptococcus mutans
and
Streptococcus
pneumoniae
. However, the association between a fructosidase and an ABC
transporter is unusual and may be specific to
L. acidophilus
. This is
a description of a previously undescribed gene locus involved in transport and
catabolism of FOS compounds, which can promote competition of beneficial
microorganisms in the human gastrointestinal tract.
Human inhibitory receptors Ig-like transcript 2 (ILT2) and ILT4 compete with CD8 for MHC class I binding and bind preferentially to HLA-G
Authors: Shiroishi Mitsunori , Tsumoto Kouhei , Amano Kimie , Shirakihara Yasuo , Colonna Marco , Braud Veronique M. , Allan David S. J. , Makadzange Azure , Rowland-Jones Sarah , Willcox Benjamin , Jones E. Yvonne , van der Merwe P. Anton , Kumagai Izumi , Maenaka Katsumi
Published: July 2003

Ig-like transcript 4 (ILT4) (also known as leukocyte Ig-like receptor 2, CD85d, and LILRB2) is a cell surface receptor expressed mainly on myelomonocytic cells, whereas ILT2 (also known as leukocyte Ig-like receptor 1, CD85j, and LILRB1) is expressed on a wider range of immune cells including subsets of natural killer and T cells. Both ILTs contain immunoreceptor tyrosine-based inhibitory receptor motifs in their cytoplasmic tails that inhibit cellular responses by recruiting phosphatases such as SHP-1 (Src homology 2 domain containing tyrosine phosphatase 1). Although these ILTs have been shown to recognize a broad range of classical and nonclassical human MHC class I molecules (MHCIs), their precise binding properties remain controversial. We have used surface plasmon resonance to analyze the interaction of soluble forms of ILT4 and ILT2 with several MHCIs. Although the range of affinities measured was quite broad (Kd= 2–45 μM), some interesting differences were observed. ILT2 generally bound with a 2- to 3-fold higher affinity than ILT4 to the same MHCI. Furthermore, ILT2 and ILT4 bound to HLA-G with a 3- to 4-fold higher affinity than to classical MHCIs, suggesting that ILT/HLA-G recognition may play a dominant role in the regulation of natural killer, T, and myelomonocytic cell activation. Finally, we show that ILT2 and ILT4 effectively compete with CD8 for MHCI binding, raising the possibility that ILT2 modulates CD8+T cell activation by blocking the CD8 binding as well as by recruiting inhibitory molecules through its immunoreceptor tyrosine-based inhibitory receptor motif.
Protein kinase A phosphorylation modulates transport of the polypyrimidine tract-binding protein
Authors: Xie Jiuyong , Lee Ji-Ann , Kress Tracy L. , Mowry Kimberly L. , Black Douglas L.
Published: July 2003

The heterogeneous nuclear ribonucleoprotein particle (hnRNP) proteins play
important roles in mRNA processing in eukaryotes, but little is known about
how they are regulated by cellular signaling pathways. The
polypyrimidine-tract binding protein (PTB, or hnRNP I) is an important
regulator of alternative pre-mRNA splicing, of viral RNA translation, and of
mRNA localization. Here we show that the nucleo-cytoplasmic transport of PTB
is regulated by the 3′,5′-cAMP-dependent protein kinase (PKA). PKA
directly phosphorylates PTB on conserved Ser-16, and PKA activation in PC12
cells induces Ser-16 phosphorylation. PTB carrying a Ser-16 to alanine
mutation accumulates normally in the nucleus. However, export of this mutant
protein from the nucleus is greatly reduced in heterokaryon shuttling assays.
Conversely, hyperphosphorylation of PTB by coexpression with the catalytic
subunit of PKA results in the accumulation of PTB in the cytoplasm. This
accumulation is again specifically blocked by the S16A mutation. Similarly, in
Xenopus
oocytes, the phospho-Ser-16-PTB is restricted to the
cytoplasm, whereas the non-Ser-16-phosphorylated PTB is nuclear. Thus, direct
PKA phosphorylation of PTB at Ser-16 modulates the nucleo-cytoplasmic
distribution of PTB. This phosphorylation likely plays a role in the
cytoplasmic function of PTB.
The Rieske FeS protein encoded and synthesized within mitochondria complements a deficiency in the nuclear gene
Authors: Golik Pawel , Bonnefoy Nathalie , Szczepanek Tomasz , Saint-Georges Yann , Lazowska Jaga
Published: July 2003

The Rieske FeS protein, an essential catalytic subunit of the mitochondrial
cytochrome
bc1
complex, is encoded in yeast by the nuclear gene
RIP1
, whose deletion leads to a respiratory-deficient phenotype. By
using biolistic transformation, we have relocated the nuclear
RIP1
gene into mitochondria. To allow its expression within the organelle and to
direct its integration downstream of the
cox1
gene, we have fused the
3′ end of the
Saccharomyces douglasii cox1
gene upstream of the
mitochondrial copy of
RIP1
(
RIP1
m
) flanked by the
Saccharomyces cerevisiae cox1
promoter and terminator regions. We
show that
RIP1
m
integrated between the
cox1
and
atp8
genes is mitotically stable and expressed, and it complements a
deletion of the nuclear gene. Immunodetection experiments demonstrate that the
mitochondrial genome containing
RIP1
m
is able to produce
the Rip1 protein in lower steady-state amounts than the wild type but still
sufficient to maintain a functional cytochrome
bc1
complex and
respiratory competence to a
RIP1
-deleted strain. Thus, this
recombined mitochondrial genome is a fully functional mitochondrial chromosome
with an extended gene content. This successful mitochondrial expression of a
nuclear gene essential for respiration can be viewed at the evolutionary level
as an artificial reversal of evolutionary events.
Evidence for association of schizophrenia with genetic variation in the 8p21.3 gene,PPP3CC, encoding the calcineurin gamma subunit
Authors: Gerber David J. , Hall Diana , Miyakawa Tsuyoshi , Demars Sandra , Gogos Joseph A. , Karayiorgou Maria , Tonegawa Susumu
Published: July 2003

Schizophrenia is a severe psychiatric disorder characterized by a complex mode of inheritance. Forebrain-specific CNB knockout mice display a spectrum of behavioral abnormalities related to altered behaviors observed in schizophrenia patients. To examine whether calcineurin dysfunction is involved in schizophrenia etiology, we undertook studies of an initial subset of calcineurin-related genes, prioritizing ones that map to loci previously implicated in schizophrenia by linkage studies. Transmission disequilibrium studies in a large sample of affected families detected association of thePPP3CCgene, which encodes the calcineurin γ catalytic subunit, with disease. Our results identifyPPP3CC, located at 8p21.3, as a potential schizophrenia susceptibility gene and support the proposal that alterations in calcineurin signaling contribute to schizophrenia pathogenesis.
Ubiquitin-mediated sequestration of normal cellular proteins into polyglutamine aggregates
Authors: Donaldson Kathryn M. , Li Wei , Ching Keith A. , Batalov Serge , Tsai Chih-Cheng , Joazeiro Claudio A. P.
Published: July 2003

A hallmark of most neurodegenerative diseases, including those caused by
polyglutamine expansion, is the formation of ubiquitin (Ub)-positive protein
aggregates in affected neurons. This finding suggests that the Ub system may
be involved in common mechanisms underlying these otherwise unrelated
diseases. Here we report the finding of ataxin-3 (Atx-3), whose mutation is
implicated in the neurodegenerative disease spinocerebellar ataxia type 3, in
a bioinformatics search of the human genome for components of the Ub system.
We show that wild-type Atx-3 is a Ub-binding protein and that the interaction
of Atx-3 with Ub is mediated by motifs homologous to those found in a
proteasome subunit. Both wild-type Atx-3 and the otherwise unrelated
Ub-binding protein p62/Sequestosome-1 have been shown to be sequestered into
aggregates in affected neurons in several neurodegenerative diseases, but the
mechanism for this recruitment has remained unclear. In this article, we show
that functional Ub-binding motifs in Atx-3 and p62 proteins are required for
the localization of both proteins into aggregates in a cell-based assay that
recapitulates several features of polyglutamine disease. We propose that the
Ub-mediated sequestration of essential Ub-binding protein(s) into aggregates
may be a common mechanism contributing to the pathogenesis of
neurodegenerative diseases.
Glial expression of Borna disease virus phosphoprotein induces behavioral and neurological abnormalities in transgenic mice
Authors: Kamitani Wataru , Ono Etsuro , Yoshino Saori , Kobayashi Tsutomu , Taharaguchi Satoshi , Lee Byeong-Jae , Yamashita Makiko , Kobayashi Takeshi , Okamoto Minoru , Taniyama Hiroyuki , Tomonaga Keizo , Ikuta Kazuyoshi
Published: July 2003

One hypothesis for the etiology of behavioral disorders is that infection
by a virus induces neuronal cell dysfunctions resulting in a wide range of
behavioral abnormalities. However, a direct linkage between viral infections
and neurobehavioral disturbances associated with human psychiatric disorders
has not been identified. Here, we show that transgenic mice expressing the
phosphoprotein (P) of Borna disease virus (BDV) in glial cells develop
behavioral abnormalities, such as enhanced intermale aggressiveness,
hyperactivity, and spatial reference memory deficit. We demonstrate that the
transgenic brains exhibit a significant reduction in brain-derived
neurotrophic factor and serotonin receptor expression, as well as a marked
decrease in synaptic density. These results demonstrate that glial expression
of BDV P leads to behavioral and neurobiological disturbances resembling those
in BDV-infected animals. Furthermore, the lack of reactive astrocytosis and
neuronal degeneration in the brains indicates that P can directly induce glial
cell dysfunction and also suggests that the transgenic mice may exhibit
neuropathological and neurophysiological abnormalities resembling those of
psychiatric patients. Our results provide a new insight to explore the
relationship between viral infections and neurobehavioral disorders.
Chronic stress and age-related increases in the proinflammatory cytokine IL-6
Authors: Kiecolt-Glaser Janice K. , Preacher Kristopher J. , MacCallum Robert C. , Atkinson Cathie , Malarkey William B. , Glaser Ronald
Published: July 2003

Overproduction of IL-6, a proinflammatory cytokine, is associated with a
spectrum of age-related conditions including cardiovascular disease,
osteoporosis, arthritis, type 2 diabetes, certain cancers, periodontal
disease, frailty, and functional decline. To describe the pattern of change in
IL-6 over 6 years among older adults undergoing a chronic stressor, this
longitudinal community study assessed the relationship between chronic stress
and IL-6 production in 119 men and women who were caregiving for a spouse with
dementia and 106 noncaregivers, with a mean age at study entry of 70.58 (SD =
8.03) for the full sample. On entry into this portion of the longitudinal
study, 28 of the caregivers' spouses had already died, and an additional 50 of
the 119 spouses died during the 6 years of this study. Levels of IL-6 and
health behaviors associated with IL-6 were measured across 6 years.
Caregivers' average rate of increase in IL-6 was about four times as large as
that of noncaregivers. Moreover, the mean annual changes in IL-6 among former
caregivers did not differ from that of current caregivers even several years
after the death of the impaired spouse. There were no systematic group
differences in chronic health problems, medications, or health-relevant
behaviors that might have accounted for caregivers' steeper IL-6 slope. These
data provide evidence of a key mechanism through which chronic stressors may
accelerate risk of a host of age-related diseases by prematurely aging the
immune response.
A multifunctional plasmid-encoded replication initiation protein both recruits and positions an active helicase at the replication origin
Authors: Jiang Yong , Pacek Marcin , Helinski Donald R. , Konieczny Igor , Toukdarian Aresa
Published: July 2003

The DnaA replication initiation protein has been shown to be essential for
DNA strand opening at the AT-rich region of the replication origin of the
Escherichia coli
chromosome as well as serving to recruit and
position the DnaB replicative helicase at this open region. Homologues of the
dnaA
gene of
E. coli
have been found in most bacterial
species, and the DnaA protein has been shown to be required for the initiation
of replication of both chromosomal and plasmid DNA. For several plasmid
elements it has been found that a plasmid-encoded initiation protein is
required along with the DnaA protein to bring about opening of the AT-rich
region at the replication origin. The broad host range plasmid RK2 encodes two
forms of its replication initiation protein (TrfA-33 and TrfA-44) that differ
by an additional 98 aa at the N terminus of the larger (TrfA-44) form. Both
forms initiate replication of RK2 in
E. coli in vitro
by a
DnaA-dependent mechanism. However, as shown in this study, TrfA-44
specifically interacts with the DnaB replicative helicase of
Pseudomonas
putida
and
Pseudomonas aeruginosa
and initiates the formation of
a prepriming open complex in the absence of DnaA protein. Thus, the TrfA-44
initiation protein has the multifunctional properties of recruiting and
positioning an active form of the DnaB helicase at the RK2 replication origin
by a DnaA-independent process. This unique property for a replication
initiation protein undoubtedly plays an important role in extending the host
range of the RK2 antibiotic resistance plasmid.
Resolving the question of color naming universals
Authors: Kay Paul , Regier Terry
Published: July 2003

The existence of cross-linguistic universals in color naming is currently
contested. Early empirical studies, based principally on languages of
industrialized societies, suggested that all languages may draw on a
universally shared repertoire of color categories. Recent work, in contrast,
based on languages from nonindustrialized societies, has suggested that color
categories may not be universal. No comprehensive objective tests have yet
been conducted to resolve this issue. We conduct such tests on color naming
data from languages of both industrialized and nonindustrialized societies and
show that strong universal tendencies in color naming exist across both sorts
of language.
Like-charge attraction between polyelectrolytes induced by counterion charge density waves
Authors: Angelini Thomas E. , Liang Hongjun , Wriggers Willy , Wong Gerard C. L.
Published: July 2003

Electrostatics in aqueous media is commonly understood in terms of screened Coulomb interactions, where like-charged objects, such as polyelectrolytes, always repel. These intuitive expectations are based on mean field theories, such as the Poisson–Boltzmann formalism, which are routinely used in colloid science and computational biology [Israelachvili, J. (1992)Intermolecular and Surface Forces(Academic, London), 2nd ed.]. Like-charge attractions, however, have been observed in a variety of systems [Gelbart, W. M., Bruinsma, R. F., Pincus, P. A. & Parsegian, V. A. (2000)Phys. Today53, 38–44]. Intense theoretical scrutiny over the last 30 years suggests that counterions play a central role, but no consensus exists for the precise mechanism. We have directly observed the organization of multivalent ions on cytoskeletal filamentous actin (a well defined biological polyelectrolyte) by using synchrotron x-ray diffraction and discovered an unanticipated symmetry-breaking collective counterion mechanism for generating attractions. Surprisingly, the counterions do not form a lattice that simply follows actin's helical symmetry; rather, the counterions organize into “frozen” ripples parallel to the actin filaments and form 1D charge density waves. Moreover, this 1D counterion charge density wave couples to twist distortions of the oppositely charged actin filaments. This general cooperative molecular mechanism is analogous to the formation of polarons in ionic solids and mediates attractions by facilitating a “zipper-like” charge alignment between the counterions and the polyelectrolyte charge distribution. We believe these results can fundamentally impinge on our general understanding of electrostatics in aqueous media and are relevant to a wide range of colloidal and biomedical processes.
A natural class of robust networks
Authors: Aldana Maximino , Cluzel Philippe
Published: July 2003

As biological studies shift from molecular description to system analysis
we need to identify the design principles of large intracellular networks. In
particular, without knowing the molecular details, we want to determine how
cells reliably perform essential intracellular tasks. Recent analyses of
signaling pathways and regulatory transcription networks have revealed a
common network architecture, termed scale-free topology. Although the
structural properties of such networks have been thoroughly studied, their
dynamical properties remain largely unexplored. We present a prototype for the
study of dynamical systems to predict the functional robustness of
intracellular networks against variations of their internal parameters. We
demonstrate that the dynamical robustness of these complex networks is a
direct consequence of their scale-free topology. By contrast, networks with
homogeneous random topologies require fine-tuning of their internal parameters
to sustain stable dynamical activity. Considering the ubiquity of scale-free
networks in nature, we hypothesize that this topology is not only the result
of aggregation processes such as preferential attachment; it may also be the
result of evolutionary selective processes.
The LIM-homeobox gene
Lhx8
is required for the development of many cholinergic neurons in the mouse forebrain
Authors: Zhao Yangu , Marín Oscar , Hermesz Edit , Powell Aaron , Flames Nuria , Palkovits Miklós , Rubenstein John L. R. , Westphal Heiner
Published: July 2003

Forebrain cholinergic neurons play important roles as striatal local
circuit neurons and basal telencephalic projection neurons. The genetic
mechanisms that control development of these neurons suggest that most of them
are derived from the basal telencephalon where
Lhx8
, a LIM-homeobox
gene, is expressed. Here we report that mice with a null mutation of
Lhx8
are deficient in the development of forebrain cholinergic
neurons.
Lhx8
mutants lack the nucleus basalis, a major source of the
cholinergic input to the cerebral cortex. In addition, the number of
cholinergic neurons is reduced in several other areas of the subcortical
forebrain in
Lhx8
mutants, including the caudate-putamen, medial
septal nucleus, nucleus of the diagonal band, and magnocellular preoptic
nucleus. Although cholinergic neurons are not formed, initial steps in their
specification appear to be preserved, as indicated by a presence of cells
expressing a truncated
Lhx8
mRNA and mRNA of the homeobox gene
Gbx1
. These results provide genetic evidence supporting an important
role for
Lhx8
in development of cholinergic neurons in the
forebrain.
Dual function of Slit2 in repulsion and enhanced migration of trunk, but not vagal, neural crest cells
Authors: De Bellard Maria Elena , Rao Yi , Bronner-Fraser Marianne
Published: July 2003

Neural crest precursors to the autonomic nervous system form different derivatives depending upon their axial level of origin; for example, vagal, but not trunk, neural crest cells form the enteric ganglia of the gut. Here, we show that Slit2 is expressed at the entrance of the gut, which is selectively invaded by vagal, but not trunk, neural crest. Accordingly, only trunk neural crest cells express Robo receptors. In vivo and in vitro experiments demonstrate that trunk, not vagal, crest cells avoid cells or cell membranes expressing Slit2, thereby contributing to the differential ability of neural crest populations to invade and innervate the gut. Conversely, exposure to soluble Slit2 significantly increases the distance traversed by trunk neural crest cells. These results suggest that Slit2 can act bifunctionally, both repulsing and stimulating the motility of trunk neural crest cells.
Q-Gene: processing quantitative real-time RT–PCR data
Authors: Simon Perikles
Published: July 2003

Summary: Q-Gene is an application for the processing of quantitative real-time RT–PCR data. It offers the user the possibility to freely choose between two principally different procedures to calculate normalized gene expressions as either means of Normalized Expressions or Mean Normalized Expressions. In this contribution it will be shown that the calculation of Mean Normalized Expressions has to be used for processing simplex PCR data, while multiplex PCR data should preferably be processed by calculating Normalized Expressions. The two procedures, which are currently in widespread use and regarded as more or less equivalent alternatives, should therefore specifically be applied according to the quantification procedure used.

Availability: Web access to this program is provided at http://www.biotechniques.com/softlib/qgene.html

Contact: perikles@uni-tuebingen.de
SATCHMO: sequence alignment and tree construction using hidden Markov models
Authors: Edgar Robert C. , Sjölander Kimmen
Published: July 2003

Motivation:Aligning multiple proteins based on sequence information alone is challenging if sequence identity is low or there is a significant degree of structural divergence. We present a novel algorithm (SATCHMO) that is designed to address this challenge. SATCHMO simultaneously constructs a tree and a set of multiple sequence alignments, one for each internal node of the tree. The alignment at a given node contains all sequences within its sub-tree, and predicts which positions in those sequences are alignable and which are not. Aligned regions therefore typically get shorter on a path from a leaf to the root as sequences diverge in structure. Current methods either regard all positions as alignable (e.g. ClustalW), or align only those positions believed to be homologous across all sequences (e.g. profile HMM methods); by contrast SATCHMO makes different predictions of alignable regions in different subgroups. SATCHMO generates profile hidden Markov models at each node; these are used to determine branching order, to align sequences and to predict structurally alignable regions.

Results: In experiments on the BAliBASE benchmark alignment database, SATCHMO is shown to perform comparably to ClustalW and the UCSC SAM HMM software. Results using SATCHMO to identify protein domains are demonstrated on potassium channels, with implications for the mechanism by which tumor necrosis factor alpha affects potassium current.

Availability: The software is available for download from http://www.drive5.com/lobster/index.htm

Contact: bob@drive5.com

* To whom correspondence should be addressed.