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Patients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group.
Methods
T1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9).
Results
PTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges’ g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges’ g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (pcorrected = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (pcorrected = .001).
Conclusions
PTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.
To investigate serotonin (SERT) and dopamine (DAT) transporter availabilities in depressed patients under treatment with the selective serotonin reuptake inhibitor (SSRI) escitalopram.
Methods
27 patients (10m, 42±16y) underwent [123I]β-CIT SPECT to assess SERT and DAT availabilities at baseline and after four weeks of treatment with escitalopram. Hamilton Rating Scale for Depression (HAMD) and Beck Depression Inventory (BDI) were used for clinical ratings. Parametric maps with specific to nonspecific ratios (BPND) were calculated for each voxel using cerebellum as reference region. VOI-based BPND were calculated in striatum (DAT) and midbrain/pons (SERT).
Results
At baseline, mean DAT-BPND was 6.06±0.81 in striatum and SERT-BPND 1.94±0.18 in thalamus. There were negative correlations with age of DAT in striatum (R=-0.60; p<0.01) and SERT in thalamus (R=-0.45; p<0.05). Under treatment there was a 20% occupancy of SERT in thalamus (p < 0.0001), whereas DAT availability increased by 17% in striatum (p<0.001), notably in the younger patients; higher SERT occupancy was associated with lesser DAT increase (R=0.55, p<0.05). There was a negative correlation of baseline HAM-D and DAT availability in putamen (R=- 0.45, p<0.05).
Conclusion
DAT and SERT availabilities decreased age-dependently comparable to studies in healthy volunteers. The SSRI-induced increase in DAT was less pronounced in elderly patients, even though occupancy of SERT was higher. These findings might have implications on dosage and side effect profile of SSRI medication in older patients.
Results
At baseline, mean DAT-was 6.06±0.81 in striatum and SERT-1.94±0.18 in thalamus. There were negative correlations with age of DAT in striatum (R=-0.60; p<0.01) and SERT in thalamus (R=-0.45; p<0.05). Under treatment there was a 20% occupancy of SERT in thalamus (p < 0.0001), whereas DAT availability increased by 17% in striatum (p<0.001), notably in the younger patients; higher SERT occupancy was associated with lesser DAT increase (R=0.55, p<0.05). There was a negative correlation of baseline HAM-D and DAT availability in putamen (R=- 0.45, p<0.05).
Methods
27 patients (10m, 42±16y) underwent [123I]β-CIT SPECT to assess SERT and DAT availabilities at baseline and after four weeks of treatment with escitalopram. Hamilton Rating Scale for Depression (HAMD) and Beck Depression Inventory (BDI) were used for clinical ratings. Parametric maps with specific to nonspecific ratios (BPND) were calculated for each voxel using cerebellum as reference region. VOI-based BPND were calculated in striatum (DAT) and midbrain/pons (SERT). Results At baseline, mean DAT-was 6.06±0.81 in striatum and SERT-1.94±0.18 in thalamus. There were negative correlations with age of DAT in striatum (R=-0.60; p<0.01) and SERT in thalamus (R=-0.45; p<0.05). Under treatment there was a 20% occupancy of SERT in thalamus (p < 0.0001), whereas DAT availability increased by 17% in striatum (p<0.001), notably in the younger patients; higher SERT occupancy was associated with lesser DAT increase (R=0.55, p<0.05). There was a negative correlation of baseline HAM-D and DAT availability in putamen (R=-0.45, p<0.05).
Recent studies have provided strong evidence that variation in the gene neurocan (NCAN, rs1064395) is a common risk factor for bipolar disorder (BD) and schizophrenia. However, the possible relevance of NCAN variation to disease mechanisms in the human brain has not yet been explored. Thus, to identify a putative pathomechanism, we tested whether the risk allele has an influence on cortical thickness and folding in a well-characterized sample of patients with schizophrenia and healthy controls.
Method
Sixty-three patients and 65 controls underwent T1-weighted magnetic resonance imaging (MRI) and were genotyped for the single nucleotide polymorphism (SNP) rs1064395. Folding and thickness were analysed on a node-by-node basis using a surface-based approach (FreeSurfer).
Results
In patients, NCAN risk status (defined by AA and AG carriers) was found to be associated with higher folding in the right lateral occipital region and at a trend level for the left dorsolateral prefrontal cortex. Controls did not show any association (p > 0.05). For cortical thickness, there was no significant effect in either patients or controls.
Conclusions
This study is the first to describe an effect of the NCAN risk variant on brain structure. Our data show that the NCAN risk allele influences cortical folding in the occipital and prefrontal cortex, which may establish disease susceptibility during neurodevelopment. The findings suggest that NCAN is involved in visual processing and top-down cognitive functioning. Both major cognitive processes are known to be disturbed in schizophrenia. Moreover, our study reveals new evidence for a specific genetic influence on local cortical folding in schizophrenia.
This paper reports the development of a psychological assessment instrument for evaluating the deteriorated elderly patient. The instrument provides information on patient function in eight areas including communication abilities, cognitive status and mood. Analyses were undertaken to determine the psychometric properties of each component of the instrument. Examination of the means and standard deviations indicated that the full range was used for each scale. Examination of interrater reliability yielded values ranging from .92 to .99. Several indices that may be of use in evaluating the significance of change in test scores are also presented. Suggestions are also made for the application of this instrument in both clinical and research settings.
The fast ignitor concept for inertial confinement fusion relies on the generation of hot electrons, produced by a short-pulse ultrahigh intensity laser, which propagate through high-density plasma to deposit their energy in the compressed fuel core and heat it to ignition. In preliminary experiments designed to investigate deep heating of high-density matter, we used a 20 joule, 0.5–30 ps laser to heat solid targets, and used emission spectroscopy to measure plasma temperatures and densities achieved at large depths (2–20 microns) away from the initial target surface. The targets consisted of an Al tracer layer buried within a massive CH slab; H-like and He-like line emission was then used to diagnose plasma conditions. We observe spectra from tracer layers buried up to 20 microns deep, measure emission durations of up to 200 ps, measure plasma temperatures up to Te=650 eV, and measure electron densities above 1023 cm−3. Analysis is in progress, but the data are in reasonable agreement with heating simulations when space-charge induced inhibition is included in hot-electron transport, and this supports the conclusion that the deep heating is initiated by hot electrons.
This study examined the prevalence of HIV and other sexually transmitted infections (STIs) in pregnant women in Kinshasa, the Democratic Republic of the Congo (DRC). Between April and July 2004, antenatal attendees at two of the largest maternity clinics in Kinshasa were tested to identify HIV status, syphilis, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). HIV seroprevalence was 1·9% in 2082 women. With PCR techniques, CT and NG infections were also uncommon in the first 529 women (1·7% and 0·4%, respectively). No active syphilis infection case was identified by Treponema pallidum haemagglutination assay (TPHA) and rapid plasma reagin test (RPR). A woman's risk of HIV infection was significantly associated with her reporting a male partner having had other female sexual partners (OR 2·7, 95% CI 1·2–6·2). The continuing low seroprevalence of HIV in pregnant women from Kinshasa was confirmed. Understanding factors associated with this phenomenon could help prevent a future HIV epidemic in low HIV transmission areas in Africa.
A micro-epidemic of hantavirus infections occurred in Lower Bavaria, South-East Germany, starting in April 2004. While only three cases were registered from 2001 to 2003, a dramatically increased number of clinically apparent human hantavirus infections (n=38) was observed in 2004, plus seven additional cases by June 2005. To determine the reservoir responsible for the infections, a total of 43 rodents were trapped in Lower Bavaria. Serological and genetic investigations revealed that Puumala virus (PUUV) is dominant in the local population of bank voles. Partial PUUV S segment nucleotide sequences originating from bank voles at four different trapping sites in Lower Bavaria showed a low divergence (up to 3·1%). This is contrasted by a nucleotide sequence divergence of 14–16% to PUUV strains detected in Belgium, France, Slovakia or North-Western Germany. PUUV sequences from bank voles in Lower Bavaria represent a new PUUV subtype which seems to be responsible for the observed increase of human hantavirus infections in 2004–2005.
Escherichia coli O157 infections cause an estimated 60 deaths and 73000 illnesses annually in the United States. A marked summer peak in incidence is largely unexplained. We investigated an outbreak of E. coli O157 infections at an agricultural fair in Ohio and implicated consumption of beverages made with fairground water and sold by a geographically localized group of vendors who were all on the same branch of the fairground water distribution system. To examine county fair attendance as a risk factor for infection, we conducted two further epidemiological studies. In the first, we enhanced surveillance for E. coli O157 infections in 15 Northeast Ohio counties during the 2000 agricultural fair season and showed increased risk of E. coli O157 infection among fair attendees. In the second study, we examined Ohio Public Health Laboratory Information Service (PHLIS) data for 1999 using a time-varying covariate proportional hazards model and demonstrated an association between agricultural fairs and E. coli O157 infections, by county. Agricultural fair attendance is a risk factor for E. coli O157 infection in the United States and may contribute to the summer peak in incidence. Measures are needed to reduce transmission of enteric pathogens at agricultural fairs.
A microscopic theory of gain in a group-III nitride quantum well laser is presented. The approach, which treats carrier correlations at the level of quantum kinetic theory, gives a consistent account of plasma and excitonic effects in an inhomogeneously broadened system.
Thick silicon films with good electronic quality have been prepared by glow discharge of He-diluted SiH4 at a substrate temperature ∼150°C and subsequent annealing at 160°C for about 100 hours. The stress in the films obtained this way decreased to ∼100 MPa compared to the 350 MPa in conventional a-Si:H. The post-annealing helped to reduce the ionized dangling bond density from 2.5 × 1015 cm−3 to 7 × 1014 cm−3 without changing the internal stress. IR spectroscopy and hydrogen effusion measurements implied the existence of microvoids and tiny crystallites in the material showing satisfactory electronic properties. P-I-N diodes for radiation detection applications have been realized out of the new material.
In many applications, x-ray mulhilayer mirrors are exposed to high peak fluxes of x-rays with subsequent damage to the mirror. Mirror damage is a particularly severe problem with the use of multilayers as cavity optics for short wavelength x-ray lasers. Intense optical and x-ray radiation, from the x-ray laser plasma amplifier, often damages the multilayer mirror on time scales of hundreds of picoseconds. The phenomenon of multilayer mirror damage by pulsed xray emission has been studied using short duration (500 psec) bursts of soft x-rays from a laser produced gold plasma. The results of the experiments will be compared with some simple models and the possibility of increasing the damage thresholds of short wavelength multilayer mirrors will be discussed.
The effect of vitamin A deficiency or the lentogenic La Sota strain of Newcastle disease virus (NDV) infection, or both, on immunoglobulin (IgA and IgM) levels in bile and plasma were investigated. In addition, tissue distribution of IgA-, IgG- and IgM-containing cells was studied to establish the source of these Ig. Chickens (1-d-old) with limited vitamin A reserves were fed ad lib. on diets containing either marginal or adequate levels of vitamin A. At 4 weeks of age, half the chickens in each group were infected with NDV. The number of IgA- and IgM-containing cells was not significantly affected by vitamin A deficiency, demonstrating that neither class-switching nor homing of Ig-containing cells is influenced by vitamin A deficiency. Although bile IgM levels were not significantly different in vitamin A-deficient chickens compared with normal chickens, IgA levels were significantly lower. This decrease was even more pronounced in deficient NDV-infected chickens, despite the higher number of IgA-containing cells found in these birds. These results, together with the slightly increased levels of IgA in plasma of vitamin A-deficient chickens, suggest that the hepatobiliary transport of IgA is impaired by vitamin A deficiency and possibly also by NDV infection, although disturbed secretion by IgA-containing cells cannot be excluded
A long-term radio frequency interference monitoring program is now in progress at the Ohio State University Radio Observatory. Current observations encompass the 1-2 GHz band, measuring the signal strength in each 150 KHz subband. Preliminary results show many strong and persistent signals, and wide bands in which no signals are detected. Daily and weekly variations appear to be correlated with periods of maximum human activity such as “rush hours”. It may be that aircraft reflections are causing many of the signals to be received, and that airline schedules correlate with “rush hours”. The program is being upgraded to automatically measure the direction of arrival of each signal, as an aid to further identify it. This directional information will also be used in designing rolled edges and side shields for the co-located OSU Radio Telescope, to further reduce its vulnerability to RFI.
GaAs layers were grown in recessed silicon trenches for monolithic integration of GaAs and silicon devices. These layers were examined using cathodoluminescence (CL) and transmission electron microscopy (TEM). The CL showed no dependence on distance from the sidewall edge within its limit of resolution. Cross-sectional TEM micrographs showed the GaAs grown on the sidewall to depend on the sidewall orientation. Material grown on the near-{111} sidewalls was comparable to that grown on the well bottom, while the GaAs grown on the near-{110} sidewalls showed poorer crystal quality. A photodetector was fabricated in the recessed GaAs/Si; this device could be easily adapted to a monolithically integrated structure.
In recent years much research has centered upon whether yield differentials between bonds which differ in default risk vary systematically over the business cycle. Theory suggests that during a cyclical upswing the yield differential (or risk premium) narrows, while during a downswing the differential widens. The cyclical behavior of yield spreads is well documented in the corporate bond market [4, 8, 12, 16]. This effect has only recently been given attention in the tax-exempt bond market [1, 11]. In addition, the municipal bond market may be segmented. If tax-exempt borrowers and investors are unable to substitute between tax-exempt securities of varying default risk, changes in the relative supply of and demand for these classes of securities could produce systematic fluctuations in tax-exempt yield differentials. These effects could be produced by regulatory statutes which require that banks purchase high-grade securities and the fixed nature of bond ratings.
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