[Migration in Germany: 1945-1996].
Explore the source record for details and available documents.
Acculturation↗
Biomedical subjects
R Ulrich
Publications and source records attributed to R Ulrich.
Jackknife-based method for measuring LRP onset latency differences.
A new method based on jackknifing is presented for measuring the difference between two conditions in the onset latencies of the lateralized readiness potential (LRP). The method can be used with both stimulus- and response-locked LRPs, and simulations indicate that it provides accurate estimates of onset latency differences in many common experimental conditions.
Computer Simulation↗
Membrane thickness and PROM--high-frequency ultrasound measurements.
Premature rupture of the membranes (PROM) is still an unsolved problem in obstetrics. Neither prevention nor diagnosis nor therapy is readily available. The amniotic sac is stabilized mechanically by a dense network of collagenous fibres; in the event of PROM, the collagenous mesh is dissolved and the thickness of the amniotic sac is reduced. In a prospective study involving 32 patients, we measured the thickness of the membranes in vitro by high-frequency ultrasound and by light microscopy of histological sections, between gestational weeks 28 and 32. We compared 18 patients with premature rupture of the amnio-chorionic membrane with 14 patients following induction of labour, with intact membranes at the same gestational age in vitro. We were able to show that the membrane in the PROM group (0.54 +/- 0.9 mm) was markedly thinner with fewer collagenous fibres than in the control group (0.74 +/- 1.01 mm). The application of high-frequency ultrasound in vivo in PROM may become helpful for the prediction of PROM; further studies are therefore desirable.
Amnion↗
Motor programming of response force and movement direction.
Effects of movement advance information were assessed on the prestimulus amplitude of the lateralized readiness potential (LRP), on the contingent negative variation (CNV), and on reaction time (RT). In a precuing paradigm with movement parameters hand, direction, and force, partial precues provided advance information about either hand alone, hand plus force, or hand plus direction, and the full precue specified all response parameters. The full precue produced the shortest RTs and the largest CNV amplitude, precuing hand and force or hand and movement direction produced somewhat slower RTs and a somewhat smaller CNV amplitude, and precuing only hand yielded slowest RTs and the smallest CNV amplitude. In contrast, the LRP amplitude was largest for the full precue and was the same for the remaining precues. The CNV appears to index the central assembling of a motor program, and the LRP represents the implementation of the program at more peripheral levels.
Adult↗
Organically modified aluminosilicate mesostructures from block copolymer phases
Organically modified aluminosilicate mesostructures were synthesized from two metal alkoxides with the use of poly(isoprene-b-ethyleneoxide) block copolymers (PI-b-PEO) as the structure-directing molecules. By increasing the fraction of the inorganic precursors with respect to the polymer, morphologies expected from the phase diagrams of diblock copolymers were obtained. The length scale of the microstructures and the state of alignment were varied using concepts known from the study of block copolymers. These results suggest that the use of higher molecular weight block copolymer mesophases instead of conventional low-molecular weight surfactants may provide a simple, easily controlled pathway for the preparation of various silica-type mesostructures that extends the accessible length scale of these structures by about an order of magnitude.
Journal Article↗
A recombinant single-chain human class II MHC molecule (HLA-DR1) as a covalently linked heterotrimer of alpha chain, beta chain, and antigenic peptide, with immunogenicity in vitro and reduced affinity for bacterial superantigens.
Major histocompatibility complex (MHC) class II molecules bind to numerous peptides and display these on the cell surface for T cell recognition. In a given immune response, receptors on T cells recognize antigenic peptides that are a minor population of MHC class II-bound peptides. To control which peptides are presented to T cells, it may be desirable to use recombinant MHC molecules with covalently bound antigenic peptides. To study T cell responses to such homogeneous peptide-MHC complexes, we engineered an HLA-DR1 cDNA coding for influenza hemagglutinin, influenza matrix, or HIV p24 gag peptides covalently attached via a peptide spacer to the N terminus of the DR1 beta chain. Co-transfection with DR alpha cDNA into mouse L cells resulted in surface expression of HLA-DR1 molecules that reacted with monoclonal antibodies (mAb) specific for correctly folded HLA-DR epitopes. This suggested that the spacer and peptide did not alter expression or folding of the molecule. We then engineered an additional peptide spacer between the C terminus of a truncated beta chain (without transmembrane or cytoplasmic domains) and the N terminus of full-length DR alpha chain. Transfection of this cDNA into mouse L cells resulted in surface expression of the entire covalently linked heterotrimer of peptide, beta chain, and alpha chain with the expected molecular mass of approximately 66 kDa. These single-chain HLA-DR1 molecules reacted with mAb specific for correctly folded HLA-DR epitopes, and identified one mAb with [MHC + peptide] specificity. Affinity-purified soluble secreted single-chain molecules with truncated alpha chain moved in electrophoresis as compact class II MHC dimers. Cell surface two-chain or single-chain HLA-DR1 molecules with a covalent HA peptide stimulated HLA-DR1-restricted HA-specific T cells. They were immunogenic in vitro for peripheral blood mononuclear cells. The two-chain and single-chain HLA-DR1 molecules with covalent HA peptide had reduced binding for the bacterial superantigens staphylococcal enterotoxin A and B and almost no binding for toxic shock syndrome toxin-1. The unique properties of these engineered HLA-DR1 molecules may facilitate our understanding of the complex nature of antigen recognition and aid in the development of novel vaccines with reduced superantigen binding.
Animals↗
Tests of Race Models for Reaction Time in Experiments with Asynchronous Redundant Signals
Predictions of race models are derived for divided attention experiments in which redundant signals are presented at slightly different times. The models place constraints on the change in mean reaction time (RT) as a function of the time interval between signal onsets, and these constraints can be used to test race models within the redundant signals paradigm. Copyright 1997 Academic Press. Copyright 1997 Academic Press
Journal Article↗
Mosaic hepatitis B virus core particles allow insertion of extended foreign protein segments.
Because of its particular immunological properties, the core protein of hepatitis B virus (HBcAg) has become one of the favoured 'virus-like particles' for use as a carrier of foreign epitopes. A new strategy to construct core particles presenting extended foreign protein segments was established based on the introduction of a linker containing a translational stop codon between sequences encoding a C-terminally truncated HBcAg (HBcAg delta) and a foreign protein sequence. Expression in an Escherichia coli suppressor strain allowed the simultaneous synthesis of both HBcAg delta and a read-through fusion protein containing a part of the hantavirus nucleocapsid protein. After purification, the presence of core-like mosaic particles with HBc and hantavirus antigenicity was demonstrated by electron microscopy and immunological tests. This strategy of partial stop codon suppression should improve the use of HBcAg as a carrier of foreign epitopes by allowing insertion of long foreign sequences into particle-forming proteins. The resulting mosaic particles should be of general interest for further vaccine developments.
Amino Acid Sequence↗
Response force is sensitive to the temporal uncertainty of response stimuli.
Three experiments examined whether temporal uncertainty about the delivery of a response stimulus affects response force in a simple reaction time (RT) situation. All experiments manipulated the foreperiod; that is, the interval between a warning signal and the response stimulus. In the constant condition, foreperiod length was kept constant over a block of trials but changed from block to block. In the variable condition, foreperiod length varied randomly from trial to trial. A visual warning and response stimulus were used in Experiment 1; response force decreased with foreperiod length in the variable condition, but increased in the constant condition. This result is consistent with the hypothesis that responses are less forceful when the temporal occurrence of the response stimulus is predictable. In a second experiment with an auditory warning signal and a response stimulus, response force was less sensitive to foreperiod manipulations. The third experiment manipulated both the modality and the intensity of the response signal and employed a tactile warning signal. This experiment indicated that neither the modality nor the intensity of the response signal affects the relation between response force and foreperiod length. An extension of Näätänen's (1971) motor-readiness model accounts for the main results.
Acoustic Stimulation↗
Effects of environmental pollutants on the porcine and bovine immune systems.
Immunological examinations were done in 30 fattening pigs from three swine farms (D., M., T.) and 20 dairy cows from one cattle farm (N.) in the district of Hodonín in 1994. At the same time, samples of stable dust deposits collected in the four farms were analysed for the contents of mercury, cadmium, lead, gamma-HCH (lindane), and total DDT and polychlorinated biphenyls (PCB). Decreased blood level of lysozyme (0.92 mg/l) was found in the swine herd D. Ten percent of the pigs in the herd were affected with purulent skin lesions. The concentrations of the pollutants under study in the dust deposits collected in the herd D. were low. An increased concentration of PCB (0.263 mg/kg) in stable dust but no adverse effects on the immune system were found in the swine herd M. Eosinophilia (6.2%), increased extensity of Ascaris suum infection (25%) and a high content of lead in stable dust (11.2 mg/kg) were typical of the swine herd T. A high content of lindane (0.139 mg/kg) and an extremely high content of lead (214 mg/kg), which can participate in the immunosuppression of lymphocytes, were found in the cattle herd N. The activity of lymphocytes was depressed in 35% of the cows and the mean value was at the lower limit of the physiological range. Hazardous pollutants can affect the immune system of farm animals and their penetration into the stable environment should be prevented.
Animals↗
[Evaluation and occurrence of high-risk pollutants in animal feed factories].
Concentrations of some hazardous pollutants were studied in dust deposit samples (n = 30) taken from the indoor equipment of two feed mixture plants (FMP) in Hodonín district in 1995 and 1996; the pollutants involved mercury, cadmium, lead, hexachlorobenzene (HCB), alpha and beta hexachlorocyclohexane (HCH), lindane (gamma HCH), DDT sum, DDT isomers, polychlorinated biphenyls (Delor 103, Delor 106, PCB indicator congeners). The statistically significantly higher (P < 0.01) average concentration of mercury (0.028 mg/kg) was recorded in dust depositions (n = 15) in FMP K. in comparison with FMP R. Increased concentrations of cadmium (more than 0.5 mg/kg) were determined in dust depositions in FMP K. in 1 sample (0.582 mg/kg), of lead (more than 5.0 mg/kg) in 1 sample (7.540 mg/kg), of HCB (more than 0.01 mg/kg) in two samples (0.034 and 0.036 mg/kg), of beta HCH (more than 0.005 mg/kg) in 4 samples (0.021; 0.022; 0.023 and 0.046 mg/kg), higher DDT sum (more than 0.05 mg/kg) were determined in FMP K. in 3 samples (0.072; 0.085 and 0.190 mg/kg) and of PCB sum (more than 0.05 mg/kg) in 4 samples (0.054; 0.059; 0.074 and 1.085 mg/kg). In comparison with FMP K., dust depositions (n = 15) in FMP R. showed the statistically significantly higher (P < 0.05) average concentration of lead (5.241 mg/kg). Increased concentrations of lead were determined in dust depositions in FMP R. in 7 samples (5.040; 5.230; 6.760; 7.590; 7.620; 8.450 and 15.650 mg/kg), of beta HCH in 7 samples (0.006; 0.008; 0.022; 0.024; 0.026; 0.029 and 0.049 mg/kg), higher DDT sum were recorded in 3 samples (0.053; 0.074 and 0.126 mg/kg) and higher PCB sum in 8 samples (0.057; 0.066; 0.101; 0.134; 0.164; 0.426; 0.821 and 1.202 mg/kg). The highest average concentration of hazardous pollutants in dust depositions (n = 30) in both feed mixture plants was determined in lead (4.122 mg/kg), in a descending order followed by PCB sum (0.151 mg/kg), cadmium (0.127 mg/kg), DDT sum (0.030 mg/kg), mercury (0.019 mg/kg), lindane (0.013 mg/kg), beta HCH (0.010 mg/kg), HCB (0.004 mg/kg and alpha HCH (0.001 mg/kg). Out of PCB indicator congeners, dust depositions contained the highest quantities of congener 138 (0.022 mg/kg), congener 180 (0.018 mg/kg) and congener 153 (0.015 mg/kg). Isomer p,p-DDT was dominant in dust depositions among DDT isomers (0.019 mg/kg). Dust depositions sampled from the indoor equipment of feed mixture plants are a promising indicator of produced feed mixtures contamination with hazardous pollutants. To seek sources of feed mixtures contamination is a permanent task of veterinary service.
Animal Feed↗
Measurement of amniochorionic membrane thickness using high-frequency ultrasound.
Premature rupture of the membranes (PROM) accounts for approximately 30 per cent of all preterm deliveries. PROM is thought to be mainly due to a decrease in membrane integrity. The aim of our investigation was to determine, post-partum after 28 normal deliveries, the thickness of the amniochorionic membrane using a 20 MHz high-frequency ultrasound. The data obtained were compared with histological sections for measurement accuracy using a linear regression analysis method. The membrane thickness of the total study group was 0.83 +/- 0.11 mm (0.72-1.08 mm). Based on a statistical comparison with the histological sections, the high-frequency ultrasound examination was shown to be highly reliable, with a correlation coefficient of r = 0.96 (P < 0.0001). High-frequency ultrasonographic examinations of membrane thickness are an objective and reliable method and may be a gain to prenatal diagnostics once this method can be used in vivo.
Adolescent↗
Hamster polyomavirus-encoded proteins: gene cloning, heterologous expression and immunoreactivity.
The hamster polyomavirus (HaPV) is associated with spontaneously appearing skin epithelioma of the Syrian hamster Z3 strain. Virus particles prepared from the skin epithelioma cause lymphoma and leukemia when injected into newborn hamsters from a distinct Syrian hamster colony (HaP); in contrast to the skin epithelioma the hemopoietic tumors are virus free but accumulate viral DNA. To study the humoral immune response of HaPV-infected Z3 hamsters we produced recombinant HaPV proteins in Escherichia coli as beta-galactosidase-, TrpE- and dihydrofolate reductase-fusion proteins or as non-fused proteins. Recombinant plasmids carried segments of all putative early and late HaPV proteins. The recombinant proteins were detected in stained SDS polyacrylamide gels and in Western blots using monoclonal anti-TrpE and anti-beta-galactosidase antibodies and sera of HaPV-infected hamsters. Sera from HaPV-infected Z3 hamsters and crude lysates of all clones were applied to Western blots to characterize the humoral immune response in the animals. HaPV-specific antibodies were found to be directed against early protein segments translated from the first common exon and from the second unique exon of LT and MT, resp., as well as against the late proteins VP1 and VP2/3. The almost complete VP2 was recognized by all sera whereas VP1 was detected only by a half of the sera. Our data suggest the presence of at least 2 immunodominant regions in VP2, one in the C-terminal VP1 and at least 4 in early proteins.
Animals↗
Partial advance information and response preparation: inferences from the lateralized readiness potential.
Response speed to a signal is faster when advance information about the forthcoming movement is provided before signal onset. Although this precuing effect is well established, the location of this saving in reaction time (RT) in the information-processing system is controversial. Some authors have claimed that the precuing effect resides at a motoric level, whereas others have suggested a nonmotoric locus. The present experiments used onset latencies of the lateralized readiness potential (LRP) to locate the precuing effect. The results of 2 experiments with a highly compatible (Experiment 1) and with an incompatible (Experiment 2) stimulus-response mapping indicate that this effect resides, at least partially, in the motoric portion of RT. In addition, the LRP amplitude before signal appearance increased with the amount of advance information, supporting a muscle-specific preparation hypothesis.
Adult↗
Does immediate arousal enhance response force in simple reaction time?
Three experiments assessed the hypothesis that immediate arousal enhances response force in speeded reaction-time tasks. Immediate arousal was manipulated via the physical characteristics of a warning signal that closely preceded the imperative response signal. The first experiment revealed that responses were more forceful and faster for a loud than for a soft warning signal. The second experiment manipulated the duration of an auditory warning signal; more forceful but slower responses were obtained for longer durations of the warning signal. The third experiment employed a visual warning signal, and its intensity was either rather weak or moderately bright; more forceful responses and slightly faster responses were observed for the brighter warning signal. Although the results of Experiment 1 and 2 may agree with an arousal account, the findings of Experiment 3 argue against such an account. A stimulus-response compatibility hypothesis is suggested as one possible alternative account.
Adult↗
Adolescent psychopathology as a function of informant and risk status.
Adolescents selected for delinquency risk in a community study, their parents, and teachers completed versions of the Child Behavior Checklist, with the raw scores representing the adolescents' level of psychopathology. All three informants rated high risk adolescents as showing higher levels of delinquency as well as other forms of psychopathology, particularly anxiety, aggression, social problems, thought problems, and, to a slightly less consistent extent, withdrawn behavior. In addition, compared with parents and adolescents, teachers rated psychopathology in African-American adolescents higher than that in Anglo-American adolescents. The results are analyzed using knowledge drawn from social and child psychiatry.
Adolescent↗
Characterization of transmembrane domains 6, 7, and 8 of MalF by mutational analysis.
Oligonucleotide mutagenesis was used to isolate mutations in membrane-spanning segments 6, 7, and 8 of MalF. MalF is a cytoplasmic membrane component of the binding protein-dependent maltose transport system in Escherichia coli. The current structural model predicts eight transmembrane domains for MalF. Membrane-spanning segments 6, 7, and 8 of MalF flank or are part of the EAA-X3-G-X9-I-X-LP consensus region present in the cytoplasmic membrane subunits of the bacterial ABC transporter superfamily members. Mutations with two novel phenotypes with respect to substrate specificity of the maltose transport system were isolated. One mutant grew on minimal maltose media but not on media containing either maltoheptaose or maltoheptaose plus maltose and was thus termed dextrin dominant negative. The other class of mutations led to a maltose minus but maltoheptaose plus phenotype. Nine of the isolated mutations leading to changes in substrate specificity were tightly clustered on one face of the postulated transmembrane helix 6. A similar clustering of mutations was detected in transmembrane domain 7. The majority of mutations in membrane-spanning segment 7 led to a protease-sensitive or a conditional phenotype with respect to MalF function or both. Mutations in transmembrane domain 8 appeared to be more randomly distributed. The majority of mutations in membrane-spanning segment 8 caused a Mal+ Dex- phenotype. Six Mal+ suppressor mutations isolated to two mutations in transmembrane domain 7 changed amino acid residues in membrane-spanning segment 6 or 8.
ATP-Binding Cassette Transporters↗
Chimaera and its modern virus-like descendants.
Chimaera was a monster in ancient Greek mythology combining elements from different animal species in its body. Modern molecular biology enabled the generation of harmless but useful chimaeras consisting of elements from different nonrelated viruses. The objective is that the resulting chimaeras form highly immunogenic virus-like particles (VLPs). Such chimaeric VLPs can be used as highly efficient carriers for sequential and conformational B cell epitopes and T cell epitopes. Most VLPs are readily produced in heterologous hosts and are easy to purify. This article deals with various systems of VLPs described in this topical issue of Intervirology and makes comparisons with chimaeric replication-competent viruses, recombinant virus vectors expressing foreign proteins, and DNA vaccines.
Animals↗