Adjustable coupling and in situ variable frequency electron paramagnetic resonance probe with loop-gap resonators for spectroscopy up to X-band

In standard electron paramagnetic resonance (EPR) spectroscopy, the frequency of an experiment is set and the spectrum is acquired using the magnetic field as the independent variable. There are cases in which it is desirable instead to fix the field and tune the frequency such as when studying avoided level crossings. We have designed and tested an adjustable frequency and variable coupling EPR probe with loop-gap resonators (LGRs) that works at a temperature as low as 1.8 K. The frequency is tuned by adjusting the height of a dielectric piece of sapphire inserted into the gap of an LGR; coupling of the microwave antenna is varied with the height of the antenna above the LGR. Both coupling antenna and dielectric are located within the cryogenic sample chamber, but their motion is controlled with external micrometers located outside the cryostat. The frequency of the LGR (∼4 GHz) can be adjusted by more than 1 GHz (>25%). To cover a wide range of frequencies, different LGRs can be designed to cover frequencies up to X-band. We demonstrate the operation of our probe by mapping out avoided crossings for the Ni₄ molecular nanomagnet to determine the tunnel splittings with high precision.

Optical constants modelling in silicon nitride membrane transiently excited by EUV radiation

We hereby report on a set of transient optical reflectivity and transmissivity measurements performed on silicon nitride thin membranes excited by extreme ultraviolet (EUV) radiation from a free electron laser (FEL). Experimental data were acquired as a function of the membrane thickness, FEL fluence and probe polarization. The time dependence of the refractive index, retrieved using Jones matrix formalism, encodes the dynamics of electron and lattice excitation following the FEL interaction. The observed dynamics are interpreted in the framework of a two temperature model, which permits to extract the relevant time scales and magnitudes of the processes. We also found that in order to explain the experimental data thermo-optical effects and inter-band filling must be phenomenologically added to the model.

Slow Interatomic Coulombic Decay of Multiply Excited Neon Clusters

Ne clusters (∼5000  atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.

The FERMI free-electron lasers

FERMI is a seeded free-electron laser (FEL) facility located at the Elettra laboratory in Trieste, Italy, and is now in user operation with its first FEL line, FEL-1, covering the wavelength range between 100 and 20 nm. The second FEL line, FEL-2, a high-gain harmonic generation double-stage cascade covering the wavelength range 20-4 nm, has also completed commissioning and the first user call has been recently opened. An overview of the typical operating modes of the facility is presented.

Magnetization and microstructure dynamics in Fe/MnAs/GaAs(001): Fe magnetization reversal by a femtosecond laser pulse

Thin film magnetization reversal without applying external fields is an attractive perspective for applications in sensors and devices. One way to accomplish it is by fine-tuning the microstructure of a magnetic substrate via temperature control, as in the case of a thin Fe layer deposited on a MnAs/GaAs(001) template. This work reports a time-resolved resonant scattering study exploring the magnetic and structural properties of the Fe/MnAs system, using a 100 fs optical laser pulse to trigger local temperature variations and a 100 fs x-ray free-electron laser pulse to probe the induced magnetic and structural dynamics. The experiment provides direct evidence that a single optical laser pulse can reverse the Fe magnetization locally. It reveals that the time scale of the magnetization reversal is slower than that of the MnAs structural transformations triggered by the optical pulse, which take place after a few picoseconds already.

De novo CNV analysis implicates specific abnormalities of postsynaptic signalling complexes in the pathogenesis of schizophrenia

A small number of rare, recurrent genomic copy number variants (CNVs) are known to substantially increase susceptibility to schizophrenia. As a consequence of the low fecundity in people with schizophrenia and other neurodevelopmental phenotypes to which these CNVs contribute, CNVs with large effects on risk are likely to be rapidly removed from the population by natural selection. Accordingly, such CNVs must frequently occur as recurrent de novo mutations. In a sample of 662 schizophrenia proband-parent trios, we found that rare de novo CNV mutations were significantly more frequent in cases (5.1% all cases, 5.5% family history negative) compared with 2.2% among 2623 controls, confirming the involvement of de novo CNVs in the pathogenesis of schizophrenia. Eight de novo CNVs occurred at four known schizophrenia loci (3q29, 15q11.2, 15q13.3 and 16p11.2). De novo CNVs of known pathogenic significance in other genomic disorders were also observed, including deletion at the TAR (thrombocytopenia absent radius) region on 1q21.1 and duplication at the WBS (Williams-Beuren syndrome) region at 7q11.23. Multiple de novos spanned genes encoding members of the DLG (discs large) family of membrane-associated guanylate kinases (MAGUKs) that are components of the postsynaptic density (PSD). Two de novos also affected EHMT1, a histone methyl transferase known to directly regulate DLG family members. Using a systems biology approach and merging novel CNV and proteomics data sets, systematic analysis of synaptic protein complexes showed that, compared with control CNVs, case de novos were significantly enriched for the PSD proteome (P=1.72 × 10⁻⁶. This was largely explained by enrichment for members of the N-methyl-D-aspartate receptor (NMDAR) (P=4.24 × 10⁻⁶) and neuronal activity-regulated cytoskeleton-associated protein (ARC) (P=3.78 × 10⁻⁸) postsynaptic signalling complexes. In an analysis of 18 492 subjects (7907 cases and 10 585 controls), case CNVs were enriched for members of the NMDAR complex (P=0.0015) but not ARC (P=0.14). Our data indicate that defects in NMDAR postsynaptic signalling and, possibly, ARC complexes, which are known to be important in synaptic plasticity and cognition, play a significant role in the pathogenesis of schizophrenia.

Acute renal failure in a patient with diffuse large B-cell lymphoma: case report

INTRODUCTION

Renal parenchymal involvement is common in systemic lymphomas. In almost all cases, renal involvement appears to be a secondary process, either by direct extension from a retroperitoneal mass or via haematogenous spread in the setting of disseminated disease. Secondary renal involvement in systemic lymphomas is generally presented as multiple masses, but also as a solitary nodule. Acute renal failure by a lymphoma infiltration of the kidney is extremely rare. Primary renal non-Hodgkin's lymphoma is even more uncommon and it is a debated issue because of the absence of lymphoid tissue in normal kidneys.

CASE PRESENTATION

We report on the case of a 62-year old woman, who had melena, abdominal pain, malaise and fever. She was hospitalized at the Nephrology Clinic due to severe anemia and signs of acute renal failure. The peripheral blood smear showed the presence of dysplastic erythroblasts and hypo-granular neutrophils. Ultra-sound was performed, which showed enlarged kidneys with signs of urinary obstruction of the first degree, with swollen, hypoechogenic parenchyma. After not responding to the conducted treatment, the patient died from heart failure. An autopsy was performed and Non-Hodgkin's, diffuse large B-cell lymphoma infiltrating multiple parenchymal organs was determined as the main cause of death.

CONCLUSION

Diffuse large B-cell lymphoma with multiple organ affection and secondary renal involvement, presented as an acute renal failure is a rare case. We report on this case to update the literature concerning this topic and highlight the importance of renal biopsy in the diagnostics.

The bipolar disorder risk allele at CACNA1C also confers risk of recurrent major depression and of schizophrenia

Molecular genetic analysis offers opportunities to advance our understanding of the nosological relationship between psychiatric diagnostic categories in general, and the mood and psychotic disorders in particular. Strong evidence (P=7.0 × 10(-7)) of association at the polymorphism rs1006737 (within CACNA1C, the gene encoding the α-1C subunit of the L-type voltage-gated calcium channel) with the risk of bipolar disorder (BD) has recently been reported in a meta-analysis of three genome-wide association studies of BD, including our BD sample (N=1868) studied within the Wellcome Trust Case Control Consortium. Here, we have used our UK case samples of recurrent major depression (N=1196) and schizophrenia (N=479) and UK non-psychiatric comparison groups (N=15316) to examine the spectrum of phenotypic effect of the bipolar risk allele at rs1006737. We found that the risk allele conferred increased risk for schizophrenia (P=0.034) and recurrent major depression (P=0.013) with similar effect sizes to those previously observed in BD (allelic odds ratio ∼1.15). Our findings are evidence of some degree of overlap in the biological underpinnings of susceptibility to mental illness across the clinical spectrum of mood and psychotic disorders, and show that at least some loci can have a relatively general effect on susceptibility to diagnostic categories, as currently defined. Our findings will contribute to a better understanding of the pathogenesis of major psychiatric illness, and such knowledge should be useful in providing an etiological rationale for shaping psychiatric nosology, which is currently reliant entirely on descriptive clinical data.

A genome-wide association study in 574 schizophrenia trios using DNA pooling

The cost of genome-wide association (GWA) studies can be prohibitively high when large samples are genotyped. We conducted a GWA study on schizophrenia (SZ) and to reduce the cost, we used DNA pooling. We used a parent-offspring trios design to avoid the potential problems of population stratification. We constructed pools from 605 unaffected controls, 574 SZ patients and a third pool from all the parents of the patients. We hybridized each pool eight times on Illumina HumanHap550 arrays. We estimated the allele frequencies of each pool from the averaged intensities of the arrays. The significance level of results in the trios sample was estimated on the basis of the allele frequencies in cases and non-transmitted pseudocontrols, taking into account the technical variability of the data. We selected the highest ranked SNPs for individual genotyping, after excluding poorly performing SNPs and those that showed a trend in the opposite direction in the control pool. We genotyped 63 SNPs in 574 trios and analysed the results with the transmission disequilibrium test. Forty of those were significant at P<0.05, with the best result at P=1.2 x 10(-6) for rs11064768. This SNP is within the gene CCDC60, a coiled-coil domain gene. The third best SNP (P=0.00016) is rs893703, within RBP1, a candidate gene for schizophrenia.

Genetic utility of broadly defined bipolar schizoaffective disorder as a diagnostic concept

BACKGROUND

Psychiatric phenotypes are currently defined according to sets of descriptive criteria. Although many of these phenotypes are heritable, it would be useful to know whether any of the various diagnostic categories in current use identify cases that are particularly helpful for biological-genetic research.

AIMS

To use genome-wide genetic association data to explore the relative genetic utility of seven different descriptive operational diagnostic categories relevant to bipolar illness within a large UK case-control bipolar disorder sample.

METHOD

We analysed our previously published Wellcome Trust Case Control Consortium (WTCCC) bipolar disorder genome-wide association data-set, comprising 1868 individuals with bipolar disorder and 2938 controls genotyped for 276 122 single nucleotide polymorphisms (SNPs) that met stringent criteria for genotype quality. For each SNP we performed a test of association (bipolar disorder group v. control group) and used the number of associated independent SNPs statistically significant at P<0.00001 as a metric for the overall genetic signal in the sample. We next compared this metric with that obtained using each of seven diagnostic subsets of the group with bipolar disorder: Research Diagnostic Criteria (RDC): bipolar I disorder; manic disorder; bipolar II disorder; schizoaffective disorder, bipolar type; DSM-IV: bipolar I disorder; bipolar II disorder; schizoaffective disorder, bipolar type.

RESULTS

The RDC schizoaffective disorder, bipolar type (v. controls) stood out from the other diagnostic subsets as having a significant excess of independent association signals (P<0.003) compared with that expected in samples of the same size selected randomly from the total bipolar disorder group data-set. The strongest association in this subset of participants with bipolar disorder was at rs4818065 (P = 2.42 x 10(-7)). Biological systems implicated included gamma amniobutyric acid (GABA)(A) receptors. Genes having at least one associated polymorphism at P<10(-4) included B3GALTS, A2BP1, GABRB1, AUTS2, BSN, PTPRG, GIRK2 and CDH12.

CONCLUSIONS

Our findings show that individuals with broadly defined bipolar schizoaffective features have either a particularly strong genetic contribution or that, as a group, are genetically more homogeneous than the other phenotypes tested. The results point to the importance of using diagnostic approaches that recognise this group of individuals. Our approach can be applied to similar data-sets for other psychiatric and non-psychiatric phenotypes.

Analysis of 10 independent samples provides evidence for association between schizophrenia and a SNP flanking fibroblast growth factor receptor 2

We and others have previously reported linkage to schizophrenia on chromosome 10q25-q26 but, to date, a susceptibility gene in the region has not been identified. We examined data from 3606 single-nucleotide polymorphisms (SNPs) mapping to 10q25-q26 that had been typed in a genome-wide association study (GWAS) of schizophrenia (479 UK cases/2937 controls). SNPs with P<0.01 (n=40) were genotyped in an additional 163 UK cases and those markers that remained nominally significant at P<0.01 (n=22) were genotyped in replication samples from Ireland, Germany and Bulgaria consisting of a total of 1664 cases with schizophrenia and 3541 controls. Only one SNP, rs17101921, was nominally significant after meta-analyses across the replication samples and this was genotyped in an additional six samples from the United States/Australia, Germany, China, Japan, Israel and Sweden (n=5142 cases/6561 controls). Across all replication samples, the allele at rs17101921 that was associated in the GWAS showed evidence for association independent of the original data (OR 1.17 (95% CI 1.06-1.29), P=0.0009). The SNP maps 85 kb from the nearest gene encoding fibroblast growth factor receptor 2 (FGFR2) making this a potential susceptibility gene for schizophrenia.

Stage 2 of the Wellcome Trust UK-Irish bipolar affective disorder sibling-pair genome screen: evidence for linkage on chromosomes 6q16-q21, 4q12-q21, 9p21, 10p14-p12 and 18q22

Bipolar affective disorder (BPAD) is a common psychiatric disorder with complex genetic aetiology. We have undertaken a genome-wide scan in one of the largest samples of bipolar affected sibling pairs (ASPs) using a two-stage approach combining sample splitting and marker grid tightening. In this second stage analysis, we have examined 17 regions that achieved a nominally significant maximum likelihood LOD score (MLS) threshold of 0.74 (or 1.18 for the X-chromosome) in stage one. The second stage has added 135 ASP families to bring the total stage 2 sample to 395 ASPs. In total, 494 microsatellite markers have been used to screen the human genome at a density of 10 cM in the first stage sample (260 ASPs) and 5 cM in the second stage. Under the broad diagnostic model, two markers gave LOD scores exceeding 3 with two-point analysis: D4S392 (LOD=3.30) and D10S197 (LOD=3.18). Multipoint analysis demonstrated suggestive evidence of linkage between BPAD and chromosomal regions 6q16-q21 (MLS=2.61) and 4q12-q21 (MLS=2.38). 6q16-q21 is of particular interest because our data, together with those from two recent genome scans, make this the best supported linkage region in BPAD. Further, our data show evidence of a gender effect at this locus with increased sharing predominantly within the male-male pairs. Our scan also provides support for linkage (MLS> or =1.5) at several other regions that have been implicated in meta-analyses of bipolar disorder and/or schizophrenia including 9p21, 10p14-p12 and 18q22.

Association study of myo-inositol monophosphatase 2 (IMPA2) polymorphisms with bipolar affective disorder and response to lithium treatment

Lithium is the most effective mood-stabilizing drug in the therapy of bipolar affective disorder (BP). It is thought to exert its effect via the phosphatidylinositol signalling system. Myo-inositol monophosphatase 2 (IMPA2) codes for an enzyme in this system that is inhibited by lithium. It is located on 18p11.2, a region implicated as a BP susceptibility locus. We examined eight single-nucleotide polymorphisms (SNPs) identified within this gene for association with BP, using 237 parents-offspring trios and in 174 cases and 170 controls. No SNP showed association with BP. When good responders to lithium treatment were compared with the poor responders, some statistically significant differences emerged for two SNPs; however, the sample became too small to draw definitive conclusions. We cannot find support for the involvement of variation in IMPA2 in susceptibility to bipolar disorder, but the role of this and other genes from the phosphoinositol signalling pathway in predicting response to lithium treatment merits further investigation.

Chromosome 22q11 deletions, velo-cardio-facial syndrome and early-onset psychosis. Molecular genetic study

BACKGROUND

Velo-cardio-facial syndrome (VCFS) is associated with interstitial deletions of chromosome 22q11. About 30% of patients with VCFS have psychosis, and the rate of these deletions in schizophrenia has been reported to be about 1%. Even higher rates of VCFS deletions have been reported for childhood-onset schizophrenia.

AIMS

To test the hypothesis that there is an increased rate of VCFS among patients with early-onset psychosis (age at onset <18 years). We screened 192 early-onset patients and 329 patients with adult-onset schizophrenia.

METHOD

We genotyped the patients and 444 healthy controls for hemizygosity of five microsatellite markers and one single nucleotide polymorphism that map to the 22q11-deleted region.

RESULTS

One patient had a VCFS deletion, confirmed with semi-quantitative polymerase chain reaction. None of the controls showed a pattern of genotypes consistent with hemizygosity.

CONCLUSIONS

VCFS may be less frequent among patients with psychosis than previously suggested; this rate is not increased among early-onset patients.

Mutation screening and LD mapping in the VCFS deleted region of chromosome 22q11 in schizophrenia using a novel DNA pooling approach

We examined whether variation within six genes from the VCFS critical region at 22q11 (DGSC, Stk22A1, DGSI, Gscl, Slc25A1 and Znf74) confers susceptibility to schizophrenia. We screened the exons and flanking intronic sequence of each gene for mutations in 14 individuals with DSM-IV schizophrenia using DHPLC. All polymorphisms identified were characterised and genotyped in a sample of 184 schizophrenics and matched controls, using novel DNA pooling methods. Of the polymorphisms identified, 17 were located within exons, six were within coding sequence, and two were non-synonymous. Pooled genotyping revealed no differences in the allele frequencies for any polymorphism between cases and controls that met our pre-defined criterion (P < or = 0.1). In a complementary approach we also attempted to define the location of a schizophrenia susceptibility locus more precisely by performing association mapping using seven microsatellites spanning the VCFS region with an average inter-marker distance of 450 kb. Conventional chi(2) analysis of genotypes in 368 cases and 368 controls revealed that none of the markers was significantly associated (P < 0.05) with schizophrenia. However, evidence for significant association (P = 0.003) was obtained for D22S944 when alleles were combined. TDT analysis of D22S944 genotyped in a further 278 cases of schizophrenia and their parents failed to find any overall allele-wise significant transmission disequilibrium (chi(2) = 18.3, P = 0.17). However, individual analysis of the alleles revealed that allele 12 was excessively non-transmitted and that this almost reached significance when corrected for multiple alleles (chi(2) = 7.35, P = 0.006, P = 0.078 corrected for 13 alleles).

Dopamine transporter gene (DAT1) VNTR polymorphism in major psychiatric disorders: family-based association study in the Bulgarian population

OBJECTIVE

A 40-bp variable number tandem repeat in the 3'-UTR of dopamine transporter gene (DAT1) has been examined for association with major psychiatric disorders in several case-control studies. No significant results have been found. We used a new collection of parent-offspring trios to test for association with schizophrenia (SZ), bipolar 1 disorder (BPI) and schizoaffective (SA) disorder.

METHOD

We genotyped trios from Bulgarian origin where the proband had SZ (178 trios), BPI (77 trios) and SA (29 trios). Alleles ranging from 5 to 11 repeats were observed. The results were analysed with the extended TDT (ETDT).

RESULTS

No preferential transmission of alleles was observed for any diagnostic group. The presence of allele DAT*10 was associated with the severity and frequency of auditory hallucinations, however, this result is not significant if corrected for multiple testing.

CONCLUSION

Our results are in agreement with previous reports of a lack of association between this polymorphism and major psychiatric disorders.

A population-based study on the prevalence of Hodgkin's disease in the region of Plovdiv

The authors present the results of a ten-year cross sectional population-based epidemiologic study on the incidence-specific patterns of Hodgkin's disease. During the period 1986-1995 there were 259 new cases diagnosed with Hodgkin's disease in Plovdiv region which accounts for 26 new cases per year (range 16 to 37). There was a strong tendency towards steady increase in the HD incidence-specific rate with a median increase of 0.13 cases per year, rising from 1.05 in 1986 to 2.18 per 100.000 in 1995. The HD morbidity-specific incidence rate also increased with 1.07 new cases per year, rising from 12.41 to 21.80 cases per 100.000 in ten years. The age-specific incidence pattern shows a bimodal distribution, with the first peak occurring between the ages of 20 and 29, and the second--between 60 and 79 years of age and with a nadir of morbidity between 40 and 49 years of age. There is a strong male predominance with a male:female ratio of 1.3:1. The most common pathohistologic pattern was the nodular sclerosis type (56.75), followed by the mixed cellularity (32.05%), the lymphocyte predominance (6.18%) and the lymphocyte depletion patterns (5.02%).

Distribution of polyamine oxidase activity in rat tissues and subcellular fractions

The activity of polyamine oxidase (PAO) in rat tissues, and its subcellular distribution, were assayed using a simple polarographic method. The highest PAO activity was measured in the liver and the lowest in the skeletal muscle. In liver, kidney and uterus the highest specific PAO activity was found in the light mitochondrial fraction. PAO was not found in the microsomal fraction except in the kidney.

Polyamine oxidase activity and concentration of polyamines in tissues and serum of hamsters with transplantational pigmented melanoma IC-Sofia

The activity of polyamine oxidase (PAO) participating in the intracellular catabolitic interconversion of the polyamines and the total concentration of polyamines in some tissues of hamsters with transplantational pigmented melamoma IC-Sofia were studied. The experiments were carried out on day 0, as well as on the 11th, 15th, 21st and 27th day after the tumor transplantation. The PAO activity and the polyamine concentration were determined in tumor tissue (with the exception of day 0), in the liver, kidneys, lung and serum (without PAO). A gradual decrease of the PAO activity and a marked rise in the total concentration of polyamines were observed in the growing tumor. In the remaining tissues the PAO activity initially rose slightly until the 15th day, then dropped, whereas the polyamine concentration increased all the time. The dynamics of the enzyme activity and the polyamine concentration were most pronounced in the lung. Tumor growth was not accompanied by changes in the polyamine concentration in the serum.

Protection of monkeys against prolonged gamma-irradiation

The radioprotective effect of the Bulgarian drug Adeturone was tested on prolonged irradiated monkeys. The animals were gamma-irradiated (137Cs) in a dose of 8.3 Gy (exposure rate 3.95 X 10(-3) mA.kg-1; (0.92 R.min-1]. Adeturone, given by i.v. injection at a dose of 100 mg.kg-1 body weight according to a pre- and postradiation scheme will afford protection to monkeys by ensuring 50% survival and mitigating the severity of some symptoms of radiation disease. A similar effect was obtained with ATP-administration by two i.m. injections of 37 mg.kg-1 body weight. The survival in control group was only 5% (LD95/45).

[Comparative studies of hormonal methods for affecting the reproductive functions of cows being raised by different technics]

Studied was the effect of two raising technologies in the industrial rearing of cows (tied and loose housing) along with the effect of the use of hormonal-and-stimulating therapy on their reproductive functions. It was found that the duration of the service period with the two technologies without using hormones was considerably long (respectively 124.3 +/- 7.8 up to 133.0 +/- 5.1 days, and 138.5 +/- 8.1 up to 144.0 +/- 3.3 days). The rate of conception at first insemination with tie-up housing varied from 20.23 to 56.67 per cent, and the total conception--from 74.41 to 86.67, whereas the fertilization of a cow required 2.35 to 2.77 doses of semen. At loose box housing the conception rate varied from 25.13 to 47.69 per cent and 75.15 to 84.61 per cent, and the used doses of semen were 2.40 to 2.69. Treatment with gravohormon between the 40th to 60th day following calving raised the total conception and the conception at first insemination--54.70 and 94.70 per cent at loose box housing, and 62.65 and 95.18 per cent at tie-up housing. Combined hormonal treatment with gravohormon and oroestron within the interval of the 100th-160th day following calving with the two technologies led to the very high clinical manifestation of the estrus, however, it did not raise the conception rate. Treatment with estrumate between the 100th and the 160th day after calving produced a higher effect with regard to conception as against the combined treatment with gravohormon and oroestron. The stimulating hormonal therapy had a higher effect on the conception at first insemination with the technology of tie-up housing.