Impact of early adverse experience on complexity of adult-generated neurons.

New neurons continue to be generated in the dentate gyrus (DG) region of the hippocampus throughout adulthood, and abnormal regulation of this process has emerged as an endophenotype common to several psychiatric disorders. Previous research shows that genetic risk factors associated with schizophrenia alter the maturation of adult-generated neurons. Here, we investigate whether early adversity, a potential environmental risk factor, similarly influences adult neurogenesis. During the first 2 weeks of postnatal life, mice were subject to repeated and unpredictable periods of separation from their mothers. When the mice reached adulthood, pharmacological and retroviral labelling techniques were used to assess the generation and maturation of new neurons. We found that adult mice that were repeatedly separated from their mothers early in life had similar rates of proliferation in the DG, but had fewer numbers of cells that survived and differentiated into neurons. Furthermore, neurons generated in adulthood had less complex dendritic arborization and fewer dendritic spines. These findings indicate that early adverse experience has a long-lasting impact on both the number and the complexity of adult-generated neurons in the hippocampus, suggesting that the abnormal regulation of adult neurogenesis associated with psychiatric disorders could arise from environmental influence alone, or from complex interactions of environmental factors with genetic predisposition.

Accelerating Advanced MRI Reconstructions on GPUs.

Computational acceleration on graphics processing units (GPUs) can make advanced magnetic resonance imaging (MRI) reconstruction algorithms attractive in clinical settings, thereby improving the quality of MR images across a broad spectrum of applications. This paper describes the acceleration of such an algorithm on NVIDIA's Quadro FX 5600. The reconstruction of a 3D image with 128(3) voxels achieves up to 180 GFLOPS and requires just over one minute on the Quadro, while reconstruction on a quad-core CPU is twenty-one times slower. Furthermore, relative to the true image, the error exhibited by the advanced reconstruction is only 12%, while conventional reconstruction techniques incur error of 42%.

Standard antisera produced in ponies for the identification of bovine mycoplasmas: comparative growth-inhibition results from six laboratories.

Antisera to 10 mycoplasma species of bovine origin were produced in 10 ponies and were distributed for evaluation in growth-inhibition tests at 6 laboratories in Australia, England, Denmark, France, and the United States. Except for a few failures with some antigens produced at the 6 laboratories, the antisera induced large zones of growth inhibition in homologous, but not heterologous, systems. These antisera may be useful as standard reagents for the identification of the bovine mycoplasmas.

Serum antibody responses of neonatal and young adult pigs to transmissible gastroenteritis coronavirus.

Serum titers of virus-neutralizing (VN) antibody were 10 to 16 times higher in neonatal pigs than in young adult pigs, after single oral doses of virulent transmissible gastroenteritis virus (TGEV). To determine the reason for this higher response, sera from neonatal and young adult pigs, 18 to 21 days after exposure to TGEV, were collected and assayed for VN antibody by plaque reduction. In addition, sera of VN-positive and VN-negative neonatal pigs were analyzed for immunoglobulin classes by radial immunodiffusion technique. The competence of neonatal pigs to produce VN antibody with increased IgG levels was demonstrated. The higher antibody response seen in neonatal pigs, when compared to sera of young adult pigs, may be attributed to the increased replication of TGEV in the intestinal tracts of neonatal pigs or to the lack of other immunogens that may interfere or compete with the production of specific antibody.

Extraction, separation, and partial characterization of Brucella abortus antigens.

Brucella abortus isolates strain 19 (a vaccinal strain) and 458 (a virulent field isolate) were analyzed for antigenic differences. Whole cell preparations were extracted with detergents, salt solutions, and phenol-acetic acid-water (PAW). Antigens were separated by starch block electrophoresis and sucrose density gradient centrifugation, serotested, and chemically analyzed. Six distinct precipitin lines were observed for the PAW extract against hyperimmune bovine antisera. With sucrose density centrifugation or starch block electrophoresis, antigens were separated into (i) complement-fixing (CF) antigens and (ii) antigens that did not fix complement but formed precipitin bands. Reciprocal CF tests with purified CF antigen could not differentiate between the antigens from either isolate of Brucella.

Partial characterization of procomplementary activity of porcine serum and its relationship to the fifth component of complement.

The procomplementary factor (PCF) of porcine serum, a component that enhances the hemolytic activity of guinea pig complement, was purified by precipitation with methanol and then by diethylaminoethyl-cellulose chromatography. The PCF substituted for the 5th complement component (C5) in the complement cascade in tests with functionally purified guinea pig complement components. In contrast to human C5, PCF is heat stable at 56 C.

Direct immunoelectron microscopy of transmissible gastroenteritis virus with immunoglobulins G and A and guinea pig complement.

Porcine colostral immunoglobulin (Ig)G and IgA, isolated from transmissible gastroenteritis virus-infected sows, were compared by direct immunoelectron microscopy. It was estimated, using antibodies with a less than a twofold difference in virus-neutralizing activity, that IgG was 500 times more efficient than was IgA for coating transmissible gastroenteritis virions. Guinea pig complement enhanced the antibody coating with IgG, but did not increase virus-neutralizing activity of IgG or IgA.

Methanol precipitation of transmissible gastroenteritis virus.

Methanol precipitation of transmissible gastroenteritis virus was tested at Ph 4.0, 5.0, 6.0, and 7.0 and at methanol concentrations of 15%, 25%, and 30%. Supernatant and precipitate fractions were tested for complement-fixing and agar-diffusion soluble antigens and plaque-forming units, and were examined by electron microscopy. Virus could be obtained free of detectable agar-diffusion antigens and most of the complement-fixing antigens. Most of the virions were without peplomers after methanol treatment but they retained infectivity.

Direct immunofluorescence tests with counterstains for detection of Chlamydia psittaci in infected avian tissues.

Different methods of preparation and serological evaluation of rabbit globulins for use in fluorescent antibody conjugate and different methods of counterstaining with fluorescent antibody tests were evaluated for detection of Chlamydia psittaci in infected turkey tissues. The agar gel precipitin reaction was that chosen for testing and selecting antiserums to be used for fluorescein isothiocyanate conjugation. The fluorescent antibody staining was most pronounced with conjugate made from globulins precipitated with ammonium sulfate. A direct fluorescent antibody method with Evans blue counterstain correctly identified "coded" specimens of C. psittaci-infected and noninfected turkey air sacs. However, naphthalene black was superior to Evans blue as a counterstain when infected pericardial sacs were tested.

Production of anti-rubratoxin antibody and its use in a radioimmunoassay for rubratoxin B.

Rubratoxin B was coupled to ovalbumin using 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide HCl (ECDI) in high concentration at pH 8.0. Under these conditions it was possible to couple 13 moles of rubratoxin B per mole of ovalbumin. The conjugate was used for immunization of rabbits, and anti-rubratoxin antibody was produced. A radioimmunoassay for rubratoxin B was developed which could detect 0.1 microgram to 10 microgram of toxin using 0.21 microgram of [14C] rubratoxin (0.47 Ci/mole, 2.0 x 10(9) dpm/microgram) and 0.125 ml of anti-rubratoxin antibody.

Isolation and purification of bovine IgM by dissociating immunoglobulin-brucella complexes.

Methods for the dissociation of immunoglobulin-Brucella complexes (IgM-rich) were evaluated. The antigen-antibody complex was separated from serum by centrifugation and dissociated with either H2O, 2.0 M pH 2.0 glycine buffer, or various concentrations of KSCN. Optimal antibody recoveries for KSCN were obtained using 1.0--2.0 M KSCN. Dissociation of the complex with water resulted in the highest recovery of antibody and the glycine buffer was lowest. Immunoelectrophoretic analysis of the eluted antibody revealed the presence of IgG and IgM. At concentrations of KSCN greater than 2.5 M, albumin-like protein was also eluted from the antibody-antigen complex. The IgM could readily be separated from IgG and albumin by gel filtration. Purified IgM was Brucella specific, monodisperse, and had a sedimentation coefficient of 20.0.

Antibody response of horses to Mycoplasma mycoides subsp capri.

In horses given whole cultures or cells of Mycoplasma mycoides subsp capri (by subcutaneous and intravenous injections), antibody responses were measured by serologic procedures. During an immunization period of 22 weeks, horses produced an antiserum that was used to identify M mycoides subsp capri by agglutination, complement-fixation, and fluorescent antibody (FA) tests, but not by the growth-inhibition test. Horses that were injected with whole cultures of M mycoides subsp capri responded better than horses that were injected with only cells, ie, antibodies were detectable sooner by agar gel diffusion and FA tests and the serums displayed more bands of precipitation. The FA reagent was stable during lyophilization and storage at 5 C for 60 days.

Colostral IgA, IgG, and IgM-IgA fractions as fluorescent antibody for the detection of the coronavirus of transmissible gastroenteritis.

Colostrum from sows and gilts inoculated with virulent transmissible gastroenteritis virus was fractionated into the 3 major immunoglobulin classes, IgA, IgG, and IgM-IgA fractions, by chromatographic and gel-filtration procedures. Each fraction was assayed for purity with rabbit anti-porcine serum and rabbit monospecific anti-porcine IgG, anti-porcine IgA, and anti-porcine IgM. These analyses showed that the IgG and IgA fractions were pure. The IgM fraction contained some IgA in the polymeric form and was designated the IgM-IgA fraction. Each Ig was assayed for virus-neutralizing activity on swine testes cells by the plaque-reduction method before and after conjugation with fluorescein isothiocyanate. On the basis of activity per milligram of protein, the virus-neutralizing titers were 1:641, 1:44, and 1:6.8 for the IgA, IgG, and IgM-IgA fractions respectively; the fluorescent antibody titers were 1:31.3, 1:0.1, and 1:15.6, respectively, for the same Ig.

Efficacy of isolated colostral IgA, IgG, and IgM(A) to protect neonatal pigs against the coronavirus of transmissible gastroenteritis.

To ascertain what class of immunoglobulin (Ig; IgA, IgG, or IgM) is most efficacious in protection, a large quantity of colostrum from sows immunized with virulent transmissible gastroenteritis (TGE) virus was fractionated by chromatographic and gel filtration methods. The isolated IgG, IgA, and IgM(A) had specific virus-neutralizing activities of 1:7.6, 1:342, and 1:302 per milligram of protein, respectively. Each Ig was fed to groups of hysterectomy-derived colostrum-deprived neonatal pigs before and after exposure (challenge) with virulent TGE virus. The 7 pigs fed IgG survived the challenge exposure, but 2 of 7 fed IgA and 1 of 7 fed IgM(A) died of TGE. Three of the survivor pigs that had been fed IgG and 2 of the survivor pigs that had been fed IgA had increased serum antibody titers between 8 and 19 days after challenge exposure, but none of the survivor pigs fed IgM(A) had TGE antibody. In contrast, 12 of 14 virus-control pigs died of TGE and the 2 survivors had antibody conversion. The data show that all 3 Ig classes in immune colostrum will protect neonatal pigs against exposure with virulent TGE virus.

Clinical, serologic, and cross-challenge response and virus isolation in cattle infected with three bovine dermatotropic herpesviruses.

The relationship of 3 dermatotropic bovine herpes-viruses (bovine mamillitis herpesvirus, dermatotropic bovine herpesvirus, and Allerton virus) was investigated; special emphasis was on the clinical response and the development of complement-fixation and precipitating antibodies in cattle. The immune respnse in steers was determined throughout the disease and after challenge exposure of the steers with 1 of the other 2 herpesviruses. Blood samples and sections of skin were collected intermittently from infected animals and examined for presence of virus.

Identification of immunoglobulins associated with complement fixation, agglutination, and low pH buffered antigen tests for brucellosis.

Serums from infected cattle, cattle with persistent postvaccinal antibody, and serologically "positive" noninfected cattle were fractionated into major immunoglobulin classes by diethylaminoethyl (DEAE)-cellulose chromatography and by sucrose density gradient centrifugation. Each fraction was assayed for anti-Brucella activity by standard tube-agglutination test (STT), buffered tube-agglutination test (BTT), and complement-fixation test (CF). In the serums from experimentally infected cattle, anti-Brucella antibody could be found by all tests in 6 DEAE fractions and in slow, fast, and sediment regions of the density gradient. Serums from cattle with persistent postvaccinal titers had STT activity in all 6 DEAE fractions, BTT activity in 5 fractions, and CF activity in only 1 fraction. The STT and BTT activities were found in the slow and the sediment regions of the gradient, whereas the CF activity was found only in the slow region. Serums from a chronically infected animal had STT and BTT activities in 2 DEAE fractions and CF activity in only 1. The STT, BTT, and CF activities were found in the slow and the sediment regions of the gradient. The principal antibody in serums from noninfected cattle was immunoglobulin M, which had all of the CF activity and most of the STT and BTT activities. Low levels of STT and BTT activities were found in 3 other DEAE fractions. Only STT and BTT activities were found in the fast and the sediment regions of the gradient.

Partial characterization of the principal soluble antigens associated with the coronavirus of transmissible gastroenteritis by complement fixation and immunodiffusion.

A microtiter complement fixation (CF) test to detect transmissible gastroenteritis (TGE) viral antigen was developed, using TGE hyperimmune pig serum as an antibody source. Sera from TGE covalescent pigs did not fix complement by this test. Maximal virus and soluble antigen (SA) titers were obtained 36 to 48 h after inoculation of swine testes cells. Cell-associated virus and SA titers were higher than those in the culture fluid, which had to be concentrated 20X before use as antigen in agar immunodiffusion tests (ID). By sucrose density-gradient centrifugation, the SA had a buoyant density of 1.10 g/ml and could be separated from the virus that banded in the 1.19-g/ml region. Virus and SA from three different isolates of TGE had the same buoyant densities. Heating and proteolytic enzyme digestion established the protein nature of the SA. As assayed by CF and ID, there were stability differences between crude and purified preparations of SA. Antibody prepared in rabbits against the SA neutralized the TGE virus.

Comparison of methods for separating proteins using bisalbuminemia as a model.

Sera from bisalbuminemic chicken-turkey hybrids contain two albumins in equal amounts. These are observed as inherited electrophoretic variants and originate from the respective chicken and turkey parents. Sera from the hybrid birds served as a model system by which fractionating and indentification procedures for evaluating serum albumin variants were compared. The two albumins in the hybrid were isolated with preparative polyacrylamide gel electrophoresis (PAGE) and starch block preparative electrophoresis. Isoelectric focusing of the hybrid albumins resulted in the isolation of the turkey albumin. Interference of ampholines prevented the complete isolation of the chicken albumin. The two albumins in the hybrid have identical molecular weights and cannot be identified by sedimentation coefficient, gel filtration behavior, or sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Because of the close relatedness the chicken and turkey albumins in the hybrid cross reacted with rabbit anti-hybrid serum as well as with rabbit anti-chicken anti-turkey sera.