Ultrabroadband flying-focus using an axiparabola-echelon pair

Flying-focus pulses promise to revolutionize laser-driven secondary sources by decoupling the trajectory of the peak intensity from the native group velocity of the medium over distances much longer than a Rayleigh range. Previous demonstrations of the flying focus have either produced an uncontrolled trajectory or a trajectory that is engineered using chromatic methods that limit the duration of the peak intensity to picosecond scales. Here we demonstrate a controllable ultrabroadband flying focus using a nearly achromatic axiparabola-echelon pair. Spectral interferometry using an ultrabroadband superluminescent diode was used to measure designed super- and subluminal flying-focus trajectories and the effective temporal pulse duration as inferred from the measured spectral phase. The measurements demonstrate that a nearly transform- and diffraction-limited moving focus can be created over a centimeter-scale-an extended focal region more than 50 Rayleigh ranges in length. This ultrabroadband flying-focus and the novel axiparabola-echelon configuration used to produce it are ideally suited for applications and scalable to >100 TW peak powers.

Erratum: Dephasingless Laser Wakefield Acceleration [Phys. Rev. Lett. 124, 134802 (2020)]

This corrects the article DOI: 10.1103/PhysRevLett.124.134802.

Nonlinear Thomson scattering with ponderomotive control

In nonlinear Thomson scattering, a relativistic electron reradiates the photons of a laser pulse, converting optical light to x rays or beyond. While this extreme frequency conversion offers a promising source for probing high-energy-density materials and driving uncharted regimes of nonlinear quantum electrodynamics, conventional nonlinear Thomson scattering has inherent trade-offs in its scaling with laser intensity. Here we discover that the ponderomotive control afforded by spatiotemporal pulse shaping enables regimes of nonlinear Thomson scattering that substantially enhance the scaling of the radiated power, emission angle, and frequency with laser intensity. By appropriately setting the velocity of the intensity peak, a spatiotemporally shaped pulse can increase the power radiated by orders of magnitude. The enhanced scaling with laser intensity allows for operation at significantly lower electron energies or intensities.

Vacuum acceleration of electrons in a dynamic laser pulse

A planar laser pulse propagating in vacuum can exhibit an extremely large ponderomotive force. This force, however, cannot impart net energy to an electron: As the pulse overtakes the electron, the initial impulse from its rising edge is completely undone by an equal and opposite impulse from its trailing edge. Here we show that planarlike "flying focus" pulses can break this symmetry, imparting relativistic energies to electrons. The intensity peak of a flying focus-a moving focal point resulting from a chirped laser pulse focused by a chromatic lens-can travel at any subluminal velocity, forward or backward. As a result, an electron can gain enough momentum in the rising edge of the intensity peak to outrun and avoid the trailing edge. Accelerating the intensity peak can further boost the momentum gain. Theory and simulations demonstrate that these dynamic intensity peaks can backwards accelerate electrons to the MeV energies required for radiation and electron diffraction probes of high energy density materials.

Dephasingless Laser Wakefield Acceleration

Laser wakefield accelerators (LWFAs) produce extremely high gradients enabling compact accelerators and radiation sources but face design limitations, such as dephasing, occurring when trapped electrons outrun the accelerating phase of the wakefield. Here we combine spherical aberration with a novel cylindrically symmetric echelon optic to spatiotemporally structure an ultrashort, high-intensity laser pulse that can overcome dephasing by propagating at any velocity over any distance. The ponderomotive force of the spatiotemporally shaped pulse can drive a wakefield with a phase velocity equal to the speed of light in vacuum, preventing trapped electrons from outrunning the wake. Simulations in the linear regime and scaling laws in the bubble regime illustrate that this dephasingless LWFA can accelerate electrons to high energies in much shorter distances than a traditional LWFA-a single 4.5 m stage can accelerate electrons to TeV energies without the need for guiding structures.

Evolution of the Electron Distribution Function in the Presence of Inverse Bremsstrahlung Heating and Collisional Ionization

The picosecond evolution of non-Maxwellian electron distribution functions was measured in a laser-produced plasma using collective electron plasma wave Thomson scattering. During the laser heating, the distribution was measured to be approximately super-Gaussian due to inverse bremsstrahlung heating. After the heating laser turned off, collisional ionization caused further modification to the distribution function while increasing electron density and decreasing temperature. Electron distribution functions were determined using Vlasov-Fokker-Planck simulations including atomic kinetics.

Photon Acceleration in a Flying Focus

A high-intensity laser pulse propagating through a medium triggers an ionization front that can accelerate and frequency upshift the photons of a second pulse. The maximum upshift is ultimately limited by the accelerated photons outpacing the ionization front or the ionizing pulse refracting from the plasma. Here, we apply the flying focus-a moving focal point resulting from a chirped laser pulse focused by a chromatic lens-to overcome these limitations. Theory and simulations demonstrate that the ionization front produced by a flying focus can frequency upshift an ultrashort optical pulse to the extreme ultraviolet over a centimeter of propagation. An analytic model of the upshift predicts that this scheme could be scaled to a novel tabletop source of spatially coherent x rays.

Ionization Waves of Arbitrary Velocity

Flying focus is a technique that uses a chirped laser beam focused by a highly chromatic lens to produce an extended focal region within which the peak laser intensity can propagate at any velocity. When that intensity is high enough to ionize a background gas, an ionization wave will track the intensity isosurface corresponding to the ionization threshold. We report on the demonstration of such ionization waves of arbitrary velocity. Subluminal and superluminal ionization fronts were produced that propagated both forward and backward relative to the ionizing laser. All backward and all superluminal cases mitigated the issue of ionization-induced refraction that typically inhibits the formation of long, contiguous plasma channels.

Fragile X syndrome. I. An overview on its genetic mechanism

A large body of literature has accumulated within the last decade concerning the fragile X syndrome, the most common cause of X-linked mental retardation. The first article of this review summarizes the peculiar genetic mechanisms and molecular biology properties (eg, unstable DNA triplet repeats), which have been characterized since the detection of the FMR-1 gene in 1991. However, the most important question concerning the function of the FMR-1 gene is still an unresolved issue and is in need of future research. The second article of this review addresses the clinical picture, neuropsychological functioning and psychopathological characteristics of pre- and full mutation carriers.

Novel schizophrenia risk gene TCF4 influences verbal learning and memory functioning in schizophrenia patients

BACKGROUND

Recently, a role of the transcription factor 4 (TCF4) gene in schizophrenia has been reported in a large genome-wide association study. It has been hypothesized that TCF4 affects normal brain development and TCF4 has been related to different forms of neurodevelopmental disorders. Schizophrenia patients exhibit strong impairments of verbal declarative memory (VDM) functions. Thus, we hypothesized that the disease-associated C allele of the rs9960767 polymorphism of the TCF4 gene led to impaired VDM functioning in schizophrenia patients.

METHOD

The TCF4 variant was genotyped in 401 schizophrenia patients. VDM functioning was measured using the Rey Auditory Verbal Learning Test (RAVLT).

RESULTS

Carriers of the C allele were less impaired in recognition compared to those carrying the AA genotype (13.76 vs. 13.06; p = 0.049). Moreover, a trend toward higher scores in patients with the risk allele was found for delayed recall (10.24 vs. 9.41; p = 0.088). The TCF4 genotype did not influence intelligence or RAVLT immediate recall or total verbal learning.

CONCLUSION

VDM function is influenced by the TCF4 gene in schizophrenia patients. However, the elevated risk for schizophrenia is not conferred by TCF4-mediated VDM impairment.

Further evidence for a functional role of the glutamate receptor gene GRM3 in schizophrenia

In recent years, evidence has been accumulating indicating a major role of glutamate in the pathogenesis and pathophysiology of schizophrenia. Of particular importance in this regard are the metabotropic glutamate receptors (GRM). Thus, a recently published trial of the amino acid analogue LY2140023, which exerts its effects through the activation of the glutamate receptors GRM3/GRM2, showed an improvement of positive and negative symptoms comparable to treatment with olanzapine. A functional variant of GRM3 has been described which modulates synaptic glutamate levels. We assessed whether this functional variant rs6465084 is related to schizophrenia in a large sample of patients and controls. We found an increased frequency of the A allele (p=0.027) and the AA genotype (p=0.024) in schizophrenia patients. Moreover, in an assessment of schizophrenia endophenotypes, patients of the AA genotype performed poorly in the digit symbol test, a measure of attention (p=0.008). Our results provide further evidence for the potential importance of the glutamate receptor GRM3 in schizophrenia, and indicate that the novel antipsychotic LY2140023 may actually be targeting a pathogenic pathway of schizophrenia.

Experimental investigation of nasal airflow

The airway geometry of the nasal cavity is manifestly complex, and the manner in which it controls the airflow to accomplish its various physiological functions is not fully understood. Since the complex morphology and inaccessibility of the nasal passageways precludes detailed in-vivo measurements, either computational simulation or in-vitro experiments are needed to determine how anatomical form and function are related. The fabrication of a replica model of the nasal cavity, of a high optical clarity and derived from in-vivo scan data is described here, together with characteristics of the flow field investigated using particle image velocimetry (PIV) and flow visualization. Flow visualization is shown to be a capable and convenient technique for identifying key phenomena. Specifically the emergence of the jet from the internal nasal valve into the main cavity, how it impacts on the middle turbinate, and the large enhancement of dispersion that accompanies the initial appearance of flow instability are revealed as particularly significant features. The findings from the visualization experiments are complemented by PIV imaging, which provides quantitative detail on the variations in velocity in different regions of the nasal cavity. These results demonstrate the effectiveness of the cavity geometry in partitioning the flow into high shear zones, which facilitate rapid heat transfer and humidification from the nasal mucosa, and slower zones affording greater residence times to facilitate olfactory sensing. The experimental results not only provide a basis for comparison with other computational modelling but also demonstrate an alternative and flexible means to investigate complex flows, relevant to studies in different parts of the respiratory or cardiovascular systems.

Validity, reliability and objectivity of the family history method in psychiatry: a meta analysis

BACKGROUND

The family history is a widely used method in psychiatry; but data on the method's objectivity, reliability and validity shows partly diverging results.

METHOD

In October 2005, a Medline search was conducted that yielded 7 studies regarding objectivity/reliability and 13 studies regarding validity. Results for six main groups of psychiatric diagnoses and any mental disorder were combined qualitatively for objectivity/reliability, and quantitatively for validity.

RESULTS

Objectivity was generally high (kappa in the 0.80 range). Reliability was high for any mental disorder, schizophrenia, substance abuse and depression (kappa in the 0.70 range), and low or medium for anxiety (kappa between 0.30 and 0.50). Results on validity displayed an OR=148 for the family history for schizophrenia; OR=64 for mania/bipolar disorder; and OR's between 8 and 194 for substance abuse, between 3 and 37 for depression, between 5 and 350 for personality disorders, between 2.5 and 49 for anxiety, and between 2.4 and 9 for any mental disorder.

CONCLUSION

There is clear evidence that the family history provides results that are better than chance for all disorders examined. But variance among diagnostic groups and among studies is considerable.

The novel brain-specific tryptophan hydroxylase-2 gene in panic disorder

Panic disorder is a common psychiatric disorder characterized by recurrent anxiety attacks and anticipatory anxiety. Due to the severity of the symptoms of the panic attacks and the frequent additional occurrence of agoraphobia, panic disorder is an often debilitating disease. Elevation of central serotonin levels by drugs such as clomipramine represents one of the most effective treatment options for panic disorder. This points to an important role of dysregulation of the serotonergic system in the genetic etiology of panic disorder. The novel brain-specific 5-HT synthesizing enzyme, tryptophan hydroxylase-2 (TPH2), which represents the rate-limiting enzyme of 5-HT production in the brain, may therefore be of particular importance in panic disorder. We focused on the putative transcriptional control region of TPH2 and identified two novel common single nucleotide polymorphisms (SNPs) of TPH2 in and close to this region. Moreover, a recently described loss-of-function mutation of TPH2 which results in an 80% reduction of serotonin production, was assessed. In an analysis of the putative transcriptional control region SNPs in a sample of panic disorder patients and controls no association of the disorder with the TPH2 SNPs or haplotypes was found. Moreover, the loss-of-function R441H mutation of TPH2 was not present in the panic disorder patients. The results of this first study of TPH2 in panic disorder argue against an importance of allelic variation of TPH2 in the pathogenesis of panic disorder with or without agoraphobia.

Rgs 2 gene polymorphisms as modulators of anxiety in humans?

Rgs2 (regulator of G-protein signalling 2) gene recently was reported as a quantitative trait gene for anxious behaviour in mice and male Rgs2 knockout mice have been shown to be more anxious than wildtype mice. Therefore we investigated four non-coding single nucleotide polymorphisms in a sample of 173 patients with panic disorder and 173 matched controls of German descent. At the genotype level all four SNPs were associated with panic disorder (p = 0.02-0.05). At the haplotype level the strongest association was observed for a haplotype containing SNP3 and SNP 4 (subgroup men and men with agoraphobia: p = 0.01 and 0.03). This points towards a functional polymorphism at the 3' end of the gene. Our results support the hypothesis that variations of the Rgs2 gene play a role also for the development of anxiety in humans.

Norepinephrine transporter (NET) promoter and 5'-UTR polymorphisms: association analysis in panic disorder

Several biochemical and pharmacological studies suggest that the catecholaminergic system involving the norepinephrine transporter (NET) is relevant for the pathogenesis of panic disorder. Three single nucleotide polymorphisms in the promoter or untranslated 5' region of the NET gene were investigated by means of RFLP analysis in a sample of 115 German patients with panic disorder and 115 matched controls. Statistical analysis failed to show association with the overall diagnosis of panic disorder. In the subgroup of patients with panic disorder without agoraphobia, however, two polymorphisms were found to be associated with the disease (G/C (rs2397771): p < 0.05; T/C (rs2242446): p < 0.01). While our data do not support a major function of the NET gene in the development of panic disorder, it may play a role in the subgroup of panic disorder without agoraphobia.

Genetic analysis of the biosynthesis of non-ribosomal peptide- and polyketide-like antibiotics, iron uptake and biofilm formation by Bacillus subtilis A1/3

The Bacillus subtilis strain A1/3 shows exceptionally diverse antibiotic capacities compared to other B. subtilis strains. To analyze this phenomenon, mutants for the putative pantotheinyltransferase gene (pptS), and for several genes involved in non-ribosomal peptide synthesis and polyketide synthesis were constructed and characterized, using bioassays with blood cells, bacterial and fungal cells, and mass spectrometry. Among at least nine distinct bioactive compounds, five antibiotics and one siderophore activity were identified. The anti-fungal and hemolytic activities of strain A1/3 could be eliminated by mutation of the fen and srf genes essential for the synthesis of fengycins and surfactins. Both pptS- and dhb -type mutants were defective in iron uptake, indicating an inability to produce a 2,3-dihydroxybenzoate-type iron siderophore. Transposon mutants in the malonyl CoA transacylase gene resulted in the loss of hemolytic and anti-fungal activities due to the inhibition of bacillomycin L synthesis, and this led to the discovery of bmyLD-LA-LB* genes. In mutants bearing disruption mutations in polyketide (pksM- and/or pksR -like) genes, the biosynthesis of bacillaene and difficidins, respectively, was inactivated and was accompanied by the loss of discrete antibacterial activities. The formation of biofilms (pellicles) was shown to require the production of surfactins, but no other lipopeptides, indicating that surfactins serve specific developmental functions.

Association study of serotonin-2A receptor gene polymorphism and panic disorder in patients from Canada and Germany

The T102C serotonin-2A (5-HT2A) receptor gene polymorphism has been studied extensively in a number of complex psychiatric conditions with mixed results. Recently a genetic association has been described between this polymorphism and panic disorder in a Japanese sample. To evaluate the impact of the T102C polymorphism in panic disorder we genotyped triad families (panic disorder patient and parents), and cases with controls in Canadian and German samples. No significant transmission disequilibrium was observed between the alleles of the T102C 5-HT2A receptor gene polymorphism and panic disorder, nor was a significant excess of either allele found in the case control analysis. Our data suggest thus that this polymorphism is unlikely to play a major role in the pathogenesis of panic disorder.

Association of a functional 1019C>G 5-HT1A receptor gene polymorphism with panic disorder with agoraphobia

Panic disorder is a common anxiety disorder which frequently co-occurs with agoraphobia. A functional promoter polymorphism in the serotonin receptor 1A (5-HT1A) gene has been found to be associated with major depression as well as anxiety- and depression-related personality traits. We investigated a possible association between this 5-HT1A gene promoter polymorphism and panic disorder by genotyping the 1019C>G single nucleotide polymorphism in 134 panic-disorder patients with and without agoraphobia and matched 134 controls. In our sample no significant evidence of allelic association in the combined panic-disorder group was found. However, our results show a significant association with the G allele in patients with panic disorder with agoraphobia (p=0.03, n=101). In conclusion, our findings do not support a major contribution of this polymorphism to the pathogenesis of panic disorder, but provide evidence for a possible role in the subgroup with agoraphobia.

Association of the functional V158M catechol-O-methyl-transferase polymorphism with panic disorder in women

Panic disorder is an anxiety disorder with an estimated heritability of up to 48%. Pharmacological and genetic studies suggest that genes coding for proteins involved in the catecholaminergic system might be relevant for the pathogenesis of the disease. In the present study, we genotyped a single nucleotide polymorphism (472G/A=V158M) in the coding region of the catechol-O-methyl-transferase (COMT) gene in 115 patients with panic disorder and age- and sex-matched controls. Association analysis revealed a significant excess of the more active COMT allele (472G=V158) in patients with panic disorder (p=0.04), particularly in female patients (p=0.01), but not in male patients (p=1.0). The assessment of a possible interaction of the COMT polymorphism with a previously reported functional 30-bp VNTR in the monoamine oxidase A promoter (MAOALPR) in female patients did not yield significant results. Our data support a role of the 472G/A (V158M) COMT polymorphism or a nearby locus in the pathogenesis of panic disorder in women.

Association of specific haplotypes of D2 dopamine receptor gene with vulnerability to heroin dependence in 2 distinct populations

CONTEXT

Dopamine receptor-mediated pathways play critical roles in the mechanism of addiction. However, associations of the D(2) dopamine receptor gene (DRD2) with substance abuse are controversial.

OBJECTIVE

To determine whether susceptibility sites resided at DRD2.

DESIGN

Haplotype-based case-control analysis of 2 distinct populations using 10 single nucleotide polymorphisms (SNPs) with heroin dependence.

SETTING

Universities of Mainz and Bonn, Germany, and 3 local hospitals in southwestern China. Patients Cases and control subjects recruited from China (486 cases, 313 controls) and Germany (471 cases, 192 controls).

INTERVENTIONS

Genotyping for 10 SNPs by 5'-exonuclease fluorescence assays. The D' value of linkage disequilibrium and haplotypes were generated by the expectation-maximization algorithm.

MAIN OUTCOME MEASURES

Genotype, allele, and haplotype frequencies were compared between cases and controls by chi(2) tests constructed for each population. An additional 32 SNPs randomly distributed in the genome were genotyped for detecting population admixture in the 2 populations.

RESULTS

A haplotype block of 25.8 kilobases (kb) was defined by 8 SNPs extending from SNP3 (TaqIB) at the 5' end to SNP10 site (TaqIA) located 10 kb distal to the 3' end of the gene. Within this block, specific haplotype cluster A (carrying TaqIB1 allele) was associated with a high risk of heroin dependence in Chinese patients (P = 1.425 x 10(-22); odds ratio, 52.80; 95% confidence interval, 7.290-382.5 for 8-SNP analysis). A putative recombination "hot spot" was found near SNP6 (intron 6 ins/del G), creating 2 new daughter haplotypes that were associated with a lower risk of heroin dependence in Germans (P = 1.94 x 10(-11) for 8-SNP analysis). There was no evidence of population stratification in either population.

CONCLUSIONS

These results strongly support a role of DRD2 as a susceptibility gene with heroin dependence in Chinese patients and was associated with low risk of heroin dependence in Germans.

Cholecystokinin- and cholecystokinin-B-receptor gene polymorphisms in panic disorder

Panic disorder like other neuropsychiatric disorders is believed to be caused by multiple psychosocial and biological factors. Several lines of evidence point to a role for the peptide neurotransmitter cholecystokinin in the pathogenesis of panic disorder. We therefore determined the allele and genotype frequencies of a single nucleotide polymorphism in the CCK gene (-36C>T) and one CT repeat polymorphism in the CCK-B-receptor gene in a German panic disorder sample (n = 115 for CCK gene polymorphism, n = 111 for CCK-B-receptor polymorphism) and compared them with gender and age matched controls. The length of the polymorphic CT repeat alleles varies between 146 bp and 180 bp. We first analysed the results by a permutation test which provided evidence for heterogeneity between patients and controls (p=0.002). We then analysed the data as a di-allelic polymorphism with a short (146-162bp) and a long (164-180bp) allele and as a tetra-allelic polymorphism with 4 alleles (146-154bp, 156-162bp, 164-170bp, 172-180bp). In the di-allelic analysis as well as in the tetra-allelic analysis there was an excess of the longer allele (p = 0.001) or the two longer alleles (p = 0.041) respectively in patients with panic disorder. No difference between groups was observed for the -36C > T polymorphism. Our findings are consistent with the notion that genetic variation in the CCK neurotransmitter system contributes to the pathogenesis of panic disorder.

No evidence for DUP25 in patients with panic disorder using a quantitative real-time PCR approach

A duplication of chromosome 15q24-q26 (DUP25) has been reported to be associated with anxiety disorders. We tested for the presence of DUP25 in a sample of 50 patients with panic disorder and 50 controls using a quantitative real-time PCR approach. Contrary to the original finding, our results were compatible with the absence of DUP25, and no significant difference could be detected between patients and controls ( P=1.0). Thus, our study does not support the hypothesis of an involvement of DUP25 in panic disorder.

Introducing a new recruitment approach to sample collection for genetic association studies in opioid dependence

OBJECTIVE

In a modified case-control association study we tested the assumption that two polymorphisms (A(118)G in exon 1 and IVS2+31 in intron 2) of the human mu-opioid receptor gene (OPRM1) confer susceptibility to opioid dependence.

METHODS

In contrast to classical case-control studies both groups, opioid dependent cases and non-opioid dependent controls were recruited from individuals who have had access to drugs including opioids and who had been sentenced for violation of the "Dangerous Drugs Act" in Germany.

RESULTS

For the two allelic variants of OPRM1 under study we did not find evidence for association with opioid dependence. CONCLUSIONS ;Despite absence of association we think that this recruitment approach introduced here, is useful since it putatively offers a more adequate matching for case-control association studies of opioid dependent individuals.

Human nuclear transcription factor gene CREM: genomic organization, mutation screening, and association analysis in panic disorder

Panic disorder is an anxiety disorder with an estimated heritability of 48%. Variation in the gene of the nuclear transcription factor "cAMP-responsive element modulator" (CREM) might contribute to its pathogenesis. CREM knock-out mice exhibit significantly less anxiety behavior than wild-type mice and the alternative CREM gene product "inducible cAMP early repressor" (ICER) plays a pivotal role in the hypothalamo-pituitary-adrenal (HPA) axis, which is disturbed in panic disorder. We characterized the genomic organization of the human CREM gene and performed a systematic mutation screening by means of single stranded conformational analysis (SSCA) in a sample of 40 German patients with panic disorder (DSM-III-R). Four novel single nucleotide polymorphisms in CREM promoters P 1 and P 4, one trinucleotide (ATT)-repeat polymorphism in CREM promoter P 2-generating the ICER isoform-and a rare amino acid substitution in CREM exon glut 2 were identified. Association analysis in an extended sample of German patients (n = 88) revealed a significant excess of the shorter CREM P 2 promoter eight-repeat trinucleotide allele and of genotypes containing the eight-repeat trinucleotide allele in panic disorder (P = 0.02), in particular in panic disorder without agoraphobia (P = 0.001). A replication study in independent Italian (n = 76) and Spanish (n = 62) samples, however, failed to confirm this observation. This suggests that the CREM P 2 promoter trinucleotide polymorphism is not a major susceptibility factor in the pathogenesis of panic disorder. Functional analysis of the observed CREM P 2 promoter polymorphism as well as studies in independent panic disorder samples are necessary.

[Psychiatric comorbidity in risk groups of opioid addiction: a comparison between opioid dependent and non-opioid dependent prisoners (in jail due to the German narcotics law)]

Individuals who do not develop opioid dependence although they have access to opioids might differ with regard to psychiatric risk factors from opioid-exposed subjects who developed opioid dependence. To test this assumption, the present investigation compared individuals who were in jail due to the German "Dangerous Drugs Act" (i. e. particular risk group due to facilitated opioid availability) according to presence or absence of opioid dependence and psychiatric comorbidity in each group. This study design is in line with the assumption that in addition to the (postulated) environmental risk factor of facilitated availability of opioids, psychiatric risk factors enhance the likelihood for the development of opioid dependence. Opioid addicts represent a risk group, not only for other forms of substance dependence, but also psychiatric disorders like anxiety disorders, suicide attempts and specific forms of personality disorders. However the difference between opioid dependent subjects and non-opioid dependent controls was less marked than initially postulated. Alcoholism of non-opioid dependent prisoners also was associated with depressive episodes, anxiety disorders as well as cocaine dependence. Despite the high frequency of life-time psychiatric comorbidity in the opioid dependent sample, this increased comorbidity was not paralleled by psychiatric treatment. In general, the sample of prisoners investigated here, was characterized by a high frequency of psychiatric disorders including substance dependence.

Norepinephrine transporter gene (NET) variants in patients with panic disorder

Several lines of evidence suggest that catecholamines, especially norepinephrine, are implicated in the etiology and/or symptomatology of panic disorder (PD). At the cellular level, functional noradrenergic neurotransmission depends on synaptic reuptake of norepinephrine as mediated by the norepinephrine transporter (NET). A pharmacological target of agents with an established anti-panic efficacy, e.g. tricyclic antidepressants, the NET is of particular interest in PD. We investigated the NET gene for the presence of 6 naturally occurring exonic sequence variants, 5 of which give rise to amino acid substitutions (Val69Ile, Thr99Ile, Val245Ile, Val449Ile and Gly478Ser) in a population of 87 patients with PD and 89 healthy controls. Except for a silent substitution (G1287A), overall frequencies of variant alleles were low (< or =0.016). None of the variants under study was found to be associated with PD regardless of an additional diagnosis of agoraphobia.

Unsteady near wall residence times and shear exposure in model distal arterial bypass grafts

Building on previous studies of unsteady flow within model distal bypass grafts we analyse the near wall residence times and shear exposure in a 45 degrees anastomosis under symmetrical and symmetry breaking geometric configurations. We define residence time as the minimum time for a particle to exit a spherical region and shear exposure as a temporal integral of the Huber-Henky-von-Mises criterion along a particle path over a fixed time interval. Decomposing the pulsatile cycle into four equal intervals we find that the interval of peak residence time in the host vessel is from mid-deceleration to peak diastole and peak diastole to mid-acceleration. The asymmetric model is shown to have a significantly lower residence time during these intervals. Considering the shear exposure prior to the residence time evaluation we determine that a higher average shear exposure exists in the asymmetric model associated with the upstream geometry modification. Analysis of the regions of high residence time and shear exposure suggests that the "toe" region and the interface between the "heel" and bulk flow are more significant than the bed and heel region. Although the asymmetric model considered in this study reduces residence times in the host artery, the product of the measure of shear exposure and residence time is not found to be preferable. If shear exposure were to be considered as an important factor in particle activation, the findings imply that for junction optimisation, greater consideration needs to be given both to the local junction asymmetry and upstream influence on the shear history.

The dichotomy of schizophrenia and affective disorders in extended pedigrees

The paper reports the first controlled family study investigating not only 1st but also 2nd and 3rd degree relatives of patients with schizophrenia by direct diagnostic interviews. Regardless of their degree of relationship, all biological relatives of the patients were found to be at an elevated risk of schizophrenia (5.0% in 1st, 3.1% in 2nd, 1.5% in 3rd degree relatives compared to 0.8% among controls). Schizoaffective and affective disorders have also been found to be more common in the three groups of relatives but without a monotone decline of prevalence rates across the groups. Other psychiatric disorders were not found to be at an elevated risk in relatives of patients compared to controls. Thus, our findings support the hypothesis that psychotic, as well as affective disorders, aggregate in families of individuals with schizophrenia.However, in our study, the risk of schizophrenia and the risk of affective disorders correlated. Particularly, the magnitude of the risk of schizophrenia among relatives of probands with schizophrenia varied with the occurrence of affective disorders in relatives. In relatives, the risk of schizophrenia was maximal in absence of a family history of affective disorder. This constellation holds true even if only families of index cases without any affective syndrome during lifetime are considered.

Phenylacetylene macrocycles with two opposing bipyridine donor sites: syntheses, X-ray structure determinations, and Ru complexation

Reaction of the known macrocycle 1a, which contains two bipyridine units in opposing sides, with two equivalents of [Ru(bipy)2Cl2] furnishes the doubly exocyclically complexed macrocycle 8a in 55% yield. Synthesis of the shape-persistent macrocycle 1c by Hagihara-Sonogashira cross-coupling chemistry of suitably functionalized building blocks is reported. This macrocycle was also converted into a Ru complex (8c). X-ray analysis of single crystals of 1b and 1c shows a layered structure that contains "channels" filled with solvent molecules and parts of the flexible chains, with which the cycle is decorated for solubility reasons.

First tryptophan-containing weak neurotoxin from cobra venom

With the purpose of studying structure-function relationships among weak neurotoxins (called so because of their low toxicity), we have isolated a toxin (WTX) from the venom of cobra Naja kaouthia using a combination of gel-filtration and ion-exchange chromatography. The amino acid sequence of the isolated toxin was determined by means of Edman degradation and MALDI mass spectrometry, the primary structure obtained being confirmed by 1H-NMR in the course of spatial structure analysis. The WTX sequence differs slightly from that of the toxin CM-9a isolated earlier from the same venom (Joubert and Taljaard, Hoppe-Seyler's Z. Physiol. Chem., 361 (1980) 425). The differences include an extra residue (Trp36) between Ser35 and Arg37 as well as interchanging of two residues (Tyr52 and Lys50) in the C-terminal part of the toxin molecule. These changes improve the alignment that can be made with other weak neurotoxin sequences. An extended sequence comparison reveals that WTX is the first case of a tryptophan-containing weak neurotoxin isolated from cobra venom. WTX was found to compete with radioiodinated alpha-bungarotoxin for binding to the membrane-bound nicotinic acetylcholine receptor from Torpedo californica.