Erratum: Lattice Dynamics of EuO: Evidence for Giant Spin-Phonon Coupling [Phys. Rev. Lett. 116, 185501 (2016)]

This corrects the article DOI: 10.1103/PhysRevLett.116.185501.

Anomalous Lattice Dynamics of EuSi_{2} Nanoislands: Role of Interfaces Unveiled

We report a systematic lattice dynamics study of EuSi_{2} films and nanoislands by in situ nuclear inelastic scattering on ^{151}Eu and ab initio theory. The Eu-partial phonon density of states of the nanoislands exhibits anomalous excess of phonon states at low and high energies, not present in the bulk and at the EuSi_{2}(001) surface. We demonstrate that atomic vibrations along the island-substrate interface give rise to phonon states both at low and high energies, while atomic vibrations across the island-island interface result in localized high-energy phonon modes.

Lattice Dynamics of EuO: Evidence for Giant Spin-Phonon Coupling

Comprehensive studies of lattice dynamics in the ferromagnetic semiconductor EuO have been performed by a combination of inelastic x-ray scattering, nuclear inelastic scattering, and ab initio calculations. A remarkably large broadening of the transverse acoustic phonons was discovered at temperatures above and below the Curie temperature T_{C}=69  K. This result indicates a surprisingly strong momentum-dependent spin-phonon coupling induced by the spin dynamics in EuO.

Expression analysis of genes involved in apoptosis, proliferation and endoplasmic reticulum stress in ionomycin/PMA treated Jurkat cells

PURPOSE

Activation of T cells by direct stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io) results in numerous downstream signals that activate pathways enabling T cells to proliferate and produce cytokines. Inducible T cell activation is regulated predominantly at the transcriptional level. Therefore, we were interested to analyze the transcriptional activity of the 19 genes involved in the regulation of several important cellular processes.

METHODS

Quantitative real-time (RT) PCR analysis was performed using mRNA-specific primers and SybrGreen for relative mRNA expression levels of all the examined genes.

RESULTS

Our results showed c-kit expression in Jurkat cells, further confirmed by sequencing of c-kit mRNAspecific PCR product. The expected increased expression of interleukin (IL)-2 mRNA, together with moderate Ki-67 upregulation, indicate the proliferation of PMA/Io treated Jurkat cells. Significant upregulation of nuclear factor (NF)-κB, JNK and the prosurvival Bcl-2 was followed by activation of only one protein kinase RNA-like endoplasmic reticulum kinase (PERK) out of 3 main endoplasmic reticulum (ER) stress subpathways (ATF6 and spliced XBP were downregulated). NF-κB and JNK activation, as well as ERK downregulation were reactive oxygen species (ROS)-independent, shown by the lack of activation of antioxidative enzymes (SOD, NOS, GSTP1, gGCS and GR). C-kit was downregulated in the absence of exogenous SCF (c-kit ligand).

CONCLUSION

Based on these data it is concluded that the PMA/Io treatment of Jurkat cells induced increased expression of IL-2, followed by upregulation of prosurvival genes belonging to the Bcl-2 family. Neither c-kit nor the antioxidative system were activated, excluding their role in Jurkat T-cell activation in the absence of exogenous c-kit ligand SCF.

Molecular diversity and evolutionary history of rabies virus strains circulating in the Balkans

Molecular studies of European classical rabies viruses (RABV) have revealed a number of geographically clustered lineages. To study the diversity of Balkan RABV, partial nucleoprotein (N) gene sequences were analysed from a unique panel of isolates (n = 210), collected from various hosts between 1972 and 2006. All of the Balkan isolates grouped within the European/Middle East Lineage, with the majority most closely related to East European strains. A number of RABV from Bosnia & Herzegovina and Montenegro, collected between 1986 and 2006, grouped with the West European strains, believed to be responsible for the rabies epizootic that spread throughout Europe in the latter half of the 20th Century. In contrast, no Serbian RABV belonged to this sublineage. However, a distinct group of Serbian fox RABV provided further evidence for the southwards wildlife-mediated movement of rabies from Hungary, Romania and Serbia into Bulgaria. To determine the optimal region for evolutionary analysis, partial, full and concatenated N-gene and glycoprotein (G) gene sequences were compared. Whilst both the divergence times and evolutionary rates were similar irrespective of genomic region, the 95 % highest probability density (HPD) limits were significantly reduced for full N-gene and concatenated NG-gene sequences compared with partial gene sequences. Bayesian coalescent analysis estimated the date of the most common recent ancestor of the Balkan RABV to be 1885 (95 % HPD, 1852-1913), and skyline plots suggested an expansion of the local viral population in 1980-1990, which coincides with the observed emergence of fox rabies in the region.

Expression analysis of genes involved in epigenetic regulation and apoptosis in human malignant haematopoietic cell lines treated with 5-azacytidine

PURPOSE

The aim of this study was to investigate the modulation of the expression status of 10 different genes involved in epigenetic regulation and apoptosis by the DNA methyltransferase (DNMT) inhibitor 5-azacytidine (5-Aza), as markers of response to treatment, in two different human malignant haematopoietic cell lines.

METHODS

In our analysis we used the SybrGreen technology and gene-specific primers for the qRT-PCR analysis of 10 genes, in cDNA of PC-MDS and K562 cell lines, treated by 1 micromole of 5-Aza for 24h.

RESULTS

DNMT1 and DNMT3A showed statistically significant decrease of expression in 5-Aza-treated PC-MDS cells, whereas DNMT3B showed significantly decreased expression in 5-Aza-treated K562 cells. The members of the Bcl- 2 family of apoptosis-regulating genes Bcl-2 and Bax showed statistically significant differences in expression, in comparison with non-treated PC-MDS cells. Our most interesting result was the significant upregulation (re-expression) of p15, in 5-Aza-treated PC-MDS cells.

CONCLUSION

The re-expression of p15 in PC-MDS cell line evaluated by qRT-PCR makes this novel cell line a suitable model for the studies of pharmacologic demethylation as a plausible mechanism resulting in hematologic response in myelodysplastic syndrome (MDS).

Noncollinear magnetization structure at the thickness-driven spin-reorientation transition in epitaxial Fe films on W(110)

An in-plane spin-reorientation transition occurring during the growth of epitaxial Fe films on W(110) was studied in situ by using the nuclear resonant scattering of synchrotron radiation. The spin-reorientation transition originates at the Fe/W(110) interface and proceeds via a noncollinear spin structure resembling a planar domain wall that propagates towards the surface with increasing film thickness.

Vibrational properties of alpha- and sigma-phase Fe-Cr alloy

Experimental and theoretical studies, of the Fe-partial phonon density of states (PDOS) for Fe52.5Cr47.5 alloy having alpha and sigma phases were carried out. The former using the nuclear resonant inelastic x-ray scattering method, and the latter with the direct one. Characteristic features of PDOS, which distinguish one phase from the other, were revealed and successfully reproduced by the theory. Data pertinent to the dynamics such as the Lamb-Mössbauer factor, f, the kinetic energy per atom, E(k), and the mean force constant, D, were directly derived, while vibrational specific heat at constant volume, C(V), and vibrational entropy, S were calculated using the Fe partial PDOS. Based on the values of f and C(V), we determined Debye temperatures, Theta(D). An excellent agreement for some quantities derived from experiment and first-principles theory, like C(V) and quite good ones for others like D and S were obtained.

Quantitative real time-polymerase chain reaction method in Bcr-Abl translocation diagnostics

PURPOSE

The quantitative real-time polymerase chain reaction (qRT-PCR) is used in the detection of molecular events involved in leukemogenesis, such as the Bcr-Abl gene translocation, the most important factor in the pathogenesis of chronic myeloid leukaemia (CML). The main aim of our study was to test the reproducibility, specificity and sensitivity of the qRT-PCR in the detection of Bcr-Abl gene translocation.

METHODS

In complementary (c)DNA, isolated from K562 Bcr-Abl positive cell line, we performed qRT-PCR analysis with Bcr-Abl specific primers. For qRT-PCR analysis, we used serial dilutions of the newly synthesized cDNA in order to establish the detection threshold of this method.

RESULTS

Using the specific primers for the Bcr-Abl translocation, we obtained the specific translocation product in cDNA sample of K562 human erythroid leukemia cell line. qRT- PCR showed significant sensitivity with the detection threshold for the Bcr-Abl fluorescent signal, which enabled the precise detection that was accurate within a 10-fold dilution range, and a dynamic range of 5 orders of magnitude.

CONCLUSION

The results of our study showed that the application of the qRT-PCR is the optimal method for the detection of Bcr-Abl gene translocation, characterized by high reproducibility, specificity and sensitivity.

Stabilization of antiferromagnetic order in FeO nanolayers

We have studied the evolution of the magnetic state of a nanometer thick antiferromagnetic (AFM) FeO layer during its formation using nuclear resonant scattering of synchrotron radiation. In contact to ferromagnetic Fe, the FeO layer does not show magnetic order at room temperature (RT). Once embedded between two Fe layers, magnetic coupling to the adjacent ferromagnets leads to a drastic increase of the Néel temperature far above RT, while the blocking temperature remains below 30 K. The presented results evidence the role that the ferromagnetic surrounding plays in modifying the magnetic state of ultrathin AFM layers.

Vibrational properties of nanograins and interfaces in nanocrystalline materials

The vibrational dynamics of nanocrystalline Fe(90)Zr(7)B(3) was studied at various phases of crystallization. The density of phonon states (DOS) of the nanograins was separated from that of the interfaces for a wide range of grain sizes and interface thicknesses. The DOS of the nanograins does not vary with their size and down to 2 nm grains still closely resembles that of the bulk. The anomalous enhancement of the phonon states at low and high energies originates from the DOS of the interfaces and scales linearly to their atomic fraction.

Molecular epidemiology of lyssaviruses in Eurasia

The Lyssavirus genus, a member of the Rhabdoviridae family, consists of seven established related viruses (genotypes 1-7). Rabies cases in Eurasia are principally attributed to three of these genotypes, namely genotype 1 (RABV, classical rabies) and to a lesser extent genotypes 5 and 6 (European bat lyssaviruses type-1 and -2). In addition, four newly identified divergent lyssaviruses have been isolated from insectivorous bats. The molecular diversity of classical rabies viruses (genotype 1, RABV) has been studied at the global level and reference has been made to the existence of a number of European strains in a range of mammalian species. It is accepted that these viruses cluster within a 'Cosmopolitan Lineage' having ancestral roots in Europe in the 17th century before its widespread dispersal to Asia, Africa and the Americas as a result of European exploration and colonization.

Phonons in iron: from the bulk to an epitaxial monolayer

The confinement of materials in low-dimensional structures has significant impact on propagating excitations like phonons. Using the isotope-specific 57Fe nuclear resonant vibrational spectroscopy we were able to determine elastic and thermodynamic properties of ultrathin Fe films on W(110). With decreasing thickness one observes a significant increase of the mean atomic displacement that goes along with an enhancement of vibrational modes at low energies as compared to the bulk. The analysis reveals that these deviations result from atomic vibrations of the single atomic layers at the two boundaries of the film, while the atoms inside the films vibrate almost bulklike.

Phonons at the Fe(110) surface

The in-plane density of phonon states of clean Fe(110) surface was measured separately for the first, second, and further atomic monolayers using nuclear inelastic scattering of synchrotron radiation. The results show that atoms of the first layer vibrate with frequencies significantly lower and amplitudes much larger than those in the bulk, and that vibrational spectra along two perpendicular in-surface directions are different. The vibrations of the second layer are already very close to those of the bulk. The good agreement of the experimental results and the first-principles calculations allows for detailed understanding of the observed phenomena.

Molecular epidemiology of rabies viruses in Europe

Several different strains of classical rabies virus co-circulate in Europe. In order to investigate the roles of the host species and topography on the molecular epidemiology of these viruses, a 400 bp region of the nucleoprotein gene was sequenced and compared with more than 500 European virus isolates. Viruses from 21 European countries were represented including some unique panels of archived isolates from the former Republic of Yugoslavia, Estonia, the Czech Republic, Poland and Austria. Phylogenetic analysis of 198 unique sequences demonstrated numerous groups of viruses clustered at both geographical and host-species levels.

[10 years' of production and use of human rabies immunoglobulin in Yugoslavia]

Application of the rabies immunoglobuline is a compulsory part of the prophylaxis of rabies in all severe, transdermal lesions caused by rabies infected animals. Sylvatic rabies has spread in the past few years throughout the whole Yugoslavia, and human cases of rabies have also been reported in other East European countries. In order to achieve the highest level of rabies prophylaxis, apart from postinfective rabies vaccination, it is necessary to provide passive immunization using specific antibodies against rabies. After successful immunization of the young, healthy volunteers in 1990, National Blood Transfusion Institute, in cooperation with the Pasteur Institute from Novi Sad, prepared the first quantities of immunized plasma by plasmapheresis procedure and human rabies immunoglobuline. Without national production, sufficient quantities of human rabies immunoglobuline could not be provided, since the price on the world market is rather high (over $1000 per patient).

Typing of field rabies virus strains in FR Yugoslavia by limited sequence analysis and monoclonal antibodies

A total of 32 rabies virus isolates (15 of fox, 14 of cat and 3 of dog origin) from the territory of FR Yugoslavia were collected from December 1996 till February 1998 and analyzed by limited sequencing of N gene and by indirect immunofluorescence and a panel of 20 antinucleocapsid monoclonal antibodies (MAbs). All examined strains were characterized as sylvatic fox strains. Two main genetic variants were detected, 15 isolates belonging to Group I, 14 belonging to Group II, while the remaining 3 could not be classified into any group. This classification was confirmed by MAbs. The obtained results indicate at least two independent cycles of rabies transmission, probably resulting from multiple modes of transmission to the territories now belonging to FR Yugoslavia.

[Electrocardiographic changes in patients with chronic anemia]

It is well known and described in literature that cardiac symptoms such as dyspnoea, palpitations and sometimes stenocardiac pain may develop in the course of anaemia. The incidence of electrocardiographic abnormalities varies significantly in different studies ranging from 10-80%. The study is aimed to determine the incidence of certain electrocardiographic changes in anaemic and non anaemic patients (control group) before and after the stress test. PATIENTS AND METHODS OF EXAMINATION: A total of 60 patients divided in two groups were studied. Group 1 included 30 patients with anaemia, free of cardiorespiratory diseases and normal x ray findings. Control group comprised 30 healthy individuals with normal x ray findings and normal ECG findings at rest, free of anaemia and iron deficiency. The average haemoglobin value in the studied and control group was 85.6 g/L and 127 g/L, respectively. The subjects underwent submaximal ergometric test. The following electrocardiographic parameters were monitored: P wave, PR interval, R amplitude, R difference, ST segment depression, T wave, QT interval and QTc interval.

RESULTS

In the studied group of patients ECG findings revealed ST segment depression at rest in one patient (3%), while in the control group such changes were not recorded. During the stress test, ECG findings revealed ST segment depression in 10 (33%) patients, as well as in 1 (3%) patient of the control group, which proved to be statistically significant. Negative T wave at rest was recorded in no patient of the two groups, while after the stress test ECG findings revealed negative T wave in 3 (10%) patients in the studied group, and in the control group no changes were recorded. Prolonged QT interval was recorded in 8 (27%) patients of the studied group and in 1 (3%) patient of the control group (this finding was considered as statistically significant). The increased R difference was statistically significant and more frequent in the studied group (30%:3%). There were no increased QTc differences in the two groups.

DISCUSSION

The total prevalence of electrocardiographic changes in 30 patients was 64%. The high incidence of electrocardiographic changes of 79% reported by Singh was most probably the result of a larger number of patients with more severe forms of anaemia. There were no cases with sinus tachycardia or sinus bradycardia; no changes in P wave length of PR interval were recorded. Atrial extrasystole, atrial tachycardia and atrial fibrillation (reported by some authors) were nor recorded. ST segment depression at rest occurred in one patient; it was, however, smaller than 1 mm. In 10 (33%) patients ST segment depression was recorded after the stress test. Singh and Volkov reported the similar findings, but in their series significant ST segment depression was also recorded at rest (which is probably due to more severe forms of anaemia). T wave inversion was not recorded at rest, but after the stress test it appeared in 3 (10%) patients. It is reported in the referential literature that approximately 23% of the patients express T wave inversion. Prolonged QT interval was evidenced in 8 (27%) patients, which is consistent with the data reported in literature. The increased R difference by more than 18% which is, according to Stankov, the result of myocardial ischaemia, was statistically more significant in the studied group than in the control group.

CONCLUSION

Based on the results of the study it may be concluded that the prevalence of ECG abnormalities in patients with anaemia was 63%. As for the individual ECG changes the prevalence of ST segment depression was 33%, T wave inversion 10%, prolonged QT interval 27%, increased R difference 30%. The incidence of ECG abnormalities (ST segment depression and T wave inversion) was markedly higher after the stress test. The recorded electrocardiographic changes may result not only from heart diseases but also from anaemia as a sign of myocardial ischaemia.

Immunogenicity of BHK-rabies vaccine in human volunteers

The production of rabies vaccine on baby hamster kidney (BHK-21) cells for human use is discussed. Long term experience in application of this vaccine in animals, without any noticeable complications and findings of inactivation of contaminated DNA from the cell substrate by beta-propiolactone have justified its recommendation for human use. Preliminary results of applying this simple, adjuvant vaccine in volunteers, confirmed its good tolerability and immunogenicity.

[Rabies in dogs and efficacy of active immunoprophylaxis in Yugoslavia]

In this study we analyzed 36 cases of dog rabies diagnosed at the Pasteur Institute in Novi Sad during the last 10 years as well as the quality of postvaccination immunity. Most dogs had the paralytic form, more common in sylvatic rabies than furious clinical picture. 11% of dogs were aggressive, whereas 44% had injured humans, including their owners. Postvaccination immunity was examined in a group of dogs vaccinated with three domestic and one vaccine imported from abroad. Vaccination was successful in more than 70% of dogs and it is a sufficient percentage of seroconversion in dog rabies eradication. However, in dogs vaccinated only once during lifetime, the immunity was not satisfactory. That is why in primary vaccination of dogs compulsory revaccination 30 days after the first vaccine dose is suggested.

[Epizootiologic situation of rabies in 1997. Urbanization of sylvatic rabies in Yugoslavia]

The Federal Republic of Yugoslavia is situated on the border of a great sylvatic rabies epizootics occurring in central and eastern Europe. That is the reason why a relatively small number of rabid animals have been registered. In 1997, 124 rabid animals, mainly red foxes, were identified. In recent years red fox rabies epizootics in Yugoslavia has annually spread 15-20 km to the south. Rabies in domestic animals, especially dogs, was characterized with furious clinical forms and dog-to-dog transmission typical of urban rabies. Sylvatic rabies has been almost completely eradicated in some countries of western Europe in the last years, mostly due to the method of oral vaccination of foxes-the main vector of rabies.

[Economical production of rabies vaccine on cell cultures]

By producing the rabies vaccine from cell culture, this vaccination has become safe, with minimal postvaccinal reactions. The first vaccine according to this technology was produced by Pavle (Paul) Fenje, former chief of department of the Pasteur Institute in Novi Sad. Many cell cultures have been introduced so far for the rabies virus multiplication: primary hamster kidney, fetal bovine kidney, chick embryo, continuous cell line monkey kidney (VERO), human diploid cell (HDC), etc. Some possibilities of an economical rabies vaccine production from a continuous BHK-21 cell line have been discussed and recommended.

[Clinical picture of cardioborreliosis: from AV block to perimyocarditis]

The third degree A-V heart block with severe Adams-Stokes attacks in nine patients with Lyme borreliosis was described. All patients had similar clinical picture: previously healthy with syncope as abrupt onset of the disease. Data on skin changes--erythema migrans--were obtained subsequently although the patients did not recall being bitten by a tick. Diagnosis was based on clinical manifestation, and on positive serologic tests to Borrelia. After the administered therapy (on admission atropine 0.5 mg i.v., and/or isoproterenol 0.02 mcg/kg/min, temporary pace-maker in two patients; and after proved diagnosis penicillin 20 mil. unit per day 10 days, and tetracyclin 2.0 gr per day 20 days A-V block returned to sinus rhythm with normal A-V conduction, and all biochemical parameters returned to normal limits. Perimyocarditis is not rare during Lyme borreliosis, but in this case infection syndrome is dominant.