Gene expression in the prefrontal cortex during adolescence: implications for the onset of schizophrenia

<p>Abstract</p> <p>Background</p> <p>Many critical maturational processes take place in the human brain during postnatal development. In particular, the prefrontal cortex does not reach maturation until late adolescence and this stage is associated with substantial white matter volume increases. Patients with schizophrenia and other major psychiatric disorders tend to first present with overt symptoms during late adolescence/early adulthood and it has been proposed that this developmental stage represents a "window of vulnerability".</p> <p>Methods</p> <p>In this study we used whole genome microarrays to measure gene expression in post mortem prefrontal cortex tissue from human individuals ranging in age from 0 to 49 years. To identify genes specifically altered in the late adolescent period, we applied a template matching procedure. Genes were identified which showed a significant correlation to a template showing a peak of expression between ages 15 and 25.</p> <p>Results</p> <p>Approximately 2000 genes displayed an expression pattern that was significantly correlated (positively or negatively) with the template. In the majority of cases, these genes in fact reached a plateau during adolescence with only subtle changes thereafter. These include a number of genes previously associated with schizophrenia including the susceptibility gene neuregulin 1 (NRG1). Functional profiling revealed peak expression in late adolescence for genes associated with energy metabolism and protein and lipid synthesis, together with decreases for genes involved in glutamate and neuropeptide signalling and neuronal development/plasticity. Strikingly, eight myelin-related genes previously found decreased in schizophrenia brain tissue showed a peak in their expression levels in late adolescence, while the single myelin gene reported increased in patients with schizophrenia was decreased in late adolescence.</p> <p>Conclusion</p> <p>The observed changes imply that molecular mechanisms critical for adolescent brain development are disturbed in schizophrenia patients.</p

First search for 2ε, εβ+ decay of 162Er and new limit on 2β- decay of 170Er to the first excited level of 170Y

The first search for double electron capture (2ε) and electron capture with positron emission (εβ+) of 162Er to the ground state and to several excited levels of 162Dy was realized with 326 g of highly purified erbium oxide. The sample was measured over 1934 h by the ultra-low background HP Ge γ spectrometer GeCris (465 cm3) at the Gran Sasso underground laboratory. No effect was observed, the half-life limits were estimated at the level of limT_1/2 ~ 10^{15} - 10^{18} yr. A possible resonant 0ν KL1 capture in 162Er to the 2^+_1 782.7 keV excited state of 162Dy is restricted as T_1/2 > 5.0×10^{17} yr at 90% C.L. A new improved half-life limit T_1/2 > 4.1×10^{17} yr was set on the 2β− decay of 170Er to the 2^+ 84.3 keV first excited state of 170Yb

Induction of virus-specific serum antibodies in 2-week-old chickens in response to oculo-nasal infection with rLaSota and rMex mutant viruses.

<p>Chickens were inoculated with each virus (indicated on the x-axis) by the oculo-nasal route, mimicking natural infection. Sera were collected at 3 weeks post-infection. Virus-specific antibodies were measured by a hemagglutination inhibition assay using rLaSota or rMex/Las Fc virus and chicken erythrocytes.</p

First direct search for 2EC, ECbeta+ decay of 144Sm and 2beta- decay of 154Sm

The first direct search for the double electron capture (2EC) and the electron capture with positron emission (ECβ+) in 144Sm to the ground state and to the excited levels of 144Nd was realized by measuring — over 1899 h — a 342 g sample of highly purified samarium oxide (Sm2O3) with the ultra-low background HP-Ge γ spectrometer GeCris (465 cm^3) at the STELLA facility of the Gran Sasso National Laboratory (LNGS). No effect was observed and half-life limits were estimated at the level of T1/2 ∼ (0.1–1.3)×10^20 yr (90% C.L.). Moreover, for the first time half-life limits of the double beta (2β−) decay of 154Sm to several excited levels of 154Gd have been set; they are at the level of T1/2 ∼ (0.06–8) × 10^20 yr (90% C.L.)

First search for 2ε, εβ+ processes in 168Yb

The double-electron capture and the electron capture with positron emission in 168Yb have been investigated for the first time at the STELLA facility of the Gran Sasso underground laboratory (Italy) measuring 371 g of highly purified ytterbium oxide placed on the end-cap of a 465 cm3 ultra-low-background high purity Germanium detector (HPGe). No gamma associated to double beta processes in 168Yb have been observed after 2074 h of data taking. This has allowed setting the half-life limits on the level of T_1/2 circa 10^14 -10^18 yr at 90% C.L. Particularly, a lower half-life limit on a possible resonant neutrinoless double-electron capture in 168Yb to the 1403.7 keV excited state of 168Er is set as T_1/2 higher/equal 1.9 x 10^18 yr at 90% C.L. Half-life limits T_1/2^2nu(0nu) higher/equal 4.5(4.3) x 10^16 yr were set on the 2 neutrino(0 neutrino) 2beta^- decay of 176Yb to the 84.3 keV first excited level of 176Hf

Purification of cerium, neodymium and gadolinium for low background experiments

Cerium, neodymium and gadolinium contain double beta active isotopes. The most interesting are 150Nd and 160Gd (promising for 0ν2β search), 136Ce (2β+ candidate with one of the highest Q2β). The main problem of compounds containing lanthanide elements is their high radioactive contamination by uranium, radium, actinium and thorium. The new generation 2β experiments require development of methods for a deep purification of lanthanides from the radioactive elements. A combination of physical and chemical methods was applied to purify cerium, neodymium and gadolinium. Liquid-liquid extraction technique was used to remove traces of Th and U from neodymium, gadolinium and for purification of cerium from Th, U, Ra and K. Co-precipitation and recrystallization methods were utilized for further reduction of the impurities. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe gamma spectrometry. As a result of the purification procedure the radioactive contamination of gadolinium oxide (a similar purification efficiency was reached also with cerium and neodymium oxides) was decreased from 0.12 Bq/kg to 0.007 Bq/kg in 228Th, from 0.04 Bq/kg to <0.006 Bq/kg in 226Ra, and from 0.9 Bq/kg to 0.04 Bq/kg in 40K. The purification methods are much less efficient for chemically very similar radioactive elements like actinium, lanthanum and lutetium

Study of Double-beta Decay of 150Nd to the First 0+ Excited Level of 150Sm

Two-neutrino 2β decay of 150Nd to the 0+1 740.5-keV excited level of 150Sm has been investigated by using a highly purified 2.381-kg Nd2O3 sample with the help of ultra-low-background gamma spectrometer with 4 HPGe detectors (≈ 255 cm^3 each) at the Gran Sasso underground laboratory (INFN, Italy). Gamma quanta, expected in cascade after de-excitation of the 0+1 (740.5 keV) excited level of 150Sm, have been observed in the coincidence spectra accumulated over 25947 h. The half-life value has been preliminary estimated as T1/2=[6.9+4.0−1.9(stat)±1.1(syst)]×10^9 y. The data taking is in progress to reduce the statistical error