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Biomedical subjects

G Ulrich

Publications and source records attributed to G Ulrich.

At least 37 records · Page 2Linked to original sources
PubMed1993

Differences in vimentin distribution in glial cells in culture revealed with an antibody against a phosphorylated epitope.

We have previously described that spatial and temporal changes in the organization of vimentin that are correlated with protein kinase C (PKC)-induced phosphorylation of vimentin can be detected with the mouse monoclonal antibody B3 in cultures of amoeboid microglia [Ciesielski-Treska et al. (1991) J. Neurosci. Res. 29, 362-378]. The antibodies were generated to native form of vimentin-containing filaments and antibody B3 reveals a restricted immunostaining of vimentin in glial cells from human, rat and mouse origin. In the present study we show the distribution of epitope B3 analyzed by immunofluorescence within defined populations of rat glial cells. Relatively high immunoreactivity was found in Type 1 astrocytes, Type 2 astrocytes and oligodendrocytes had low immunoreactivity. Although the results suggested that in Type 1 astrocytes the phosphorylated epitope is prominent, its phosphorylation was not found to be cell cycle-dependent, and appeared unrelated to the organizational changes of intermediate filaments associated with the morphological conversion of polygonal to stellate astrocytes. As expected, the immunofluorescence was increased by exposition of astrocyte cultures to an activator of PKC, confirming our previous conclusion that the immunoreactivity of the epitope B3 depends on PKC-mediated phosphorylation. In addition, the finding that the immunofluorescence of vimentin was more homogeneous in quiescent, serum-deprived astrocytes and also in astrocytes exposed to an inhibitor of protein synthesis, cycloheximide, may suggest that phosphorylation of the epitope B3 depends on a protein factor present in fetal calf serum. The immunofluorescence studies on cultures enriched in Type 2 astrocytes and in oligodendrocytes indicate that the epitope B3 is hypophosphorylated in glial cells of this lineage and becomes dephosphorylated after terminal differentiation of oligodendrocytes. These observations suggest that in Type 2 astrocytes and in oligodendrocytes the low level of phosphorylation of vimentin could be related to the down regulation in vimentin expression.

Animals↗
PubMed1992

Line bisecting as a predictor of personal optimism and desirability of risky behaviors.

Our goal was to test whether current hemisphere predominance is a predictor of scores on standardized measures of personal optimism and preference for risk. In two between-subject experiments, current hemisphere predominance was measured by the direction and extent of line bisecting errors. Pearson correlations and median splits of the line bisecting errors showed significantly greater personal optimism and preference for risk with left hemisphere predominance. These results support previous research in which manipulation of hemisphere predominance produced similar effects on personal optimism in normal individuals and on risk taking in lesioned and normal samples. We conclude that the association of optimism and risk with left hemisphere predominance can be observed in resting as well as in manipulated situations.

Adolescent↗
PubMed1992

[Is global equivalent to multifocal? The whole and its parts in psychiatry and neurology].

According to an influential trend within contemporary neurology, psychiatry should abandon terms like "organic brain syndrome" or "dementia", which are regarded as out-dated. Such terms which imply the questionable possibility of global disturbances of the psychic apparatus, should be replaced by a classification based on detailed neuropsychological analysis. The response of psychiatry to this challenge is essentially lacking. An examination of the reasons leads us to the methodological contradiction between categorical and global models. We consider that we here are not confronted by a decision between mutually exclusive alternatives but that the two models necessarily complement each other. From this it follows that only a biperspectivistic view is adequate to the matter under consideration. This is equally requisite both for psychiatry and neurology, though an accentuation of the one or the other perspective may be expedient for each individual syndrome.

Brain Damage, Chronic↗
PubMed1991

[Prognostic value of the study of the blood flow in the fetal median cerebral artery].

Medial cerebral artery blood flow velocity waveforms were examined by pulsed Doppler ultrasound between the 28th and 41st week of pregnancy. It has been found that the vessel showed an increased resistance at the beginning of the third trimester, which significantly decreased till term. In intrauterin hypoxia the diastolic component of the blood flow velocity waveform of medial cerebral artery becomes stronger, marking the centralisation of the circulation. By their opinion the examination of the blood flow in the medial cerebral artery would be an effective additional possibility of the other intrauterine diagnostic methods (both the positive and the negative predictive value were higher than 90%) for the notifying the post-partal condition of the fetus.

Blood Flow Velocity↗
PubMed1991

Protein kinase C-induced redistribution of the cytoskeleton and phosphorylation of vimentin in cultured brain macrophages.

The phorbol ester 12-O-tetradecanoyl-acetate (TPA) induced prominent and transient changes in the organization of the cytoskeleton in cultured amoeboid microglial cells including redistribution of actin toward the center of the cells and in the subplasmalemmal region, appearance of fine actin filaments, retraction of microtubules (MT), and rearrangement of intermediate filaments (IF) containing vimentin. The possible implication of protein kinase C (PKC) in mediating the effects of TPA was suggested by a parallel shift of PKC activity from the soluble to membrane fractions and phosphorylation of several microglial proteins. The rearrangement of IF closely correlated with increased vimentin phosphorylation, detected by pulse labeling of intact cells. Two monoclonal antivimentin antibodies, B3 and V9, showed different staining patterns. Immunoreactivity with the antibody B3 was more restricted and could be abolished by treatment of fixed, permeabilized cells with alkaline phosphatase, thus suggesting that the antibody reacts with a phosphorylated epitope. Using this antibody, rearrangement of IF involving vimentin phosphorylation was detected within 15 to 60 min of treatment with 50 nM TPA and consisted in the appearance of intense perinuclear fluorescent label. This perinuclear fluorescence persisted up to 24 hr after TPA removal and gradually diminished during the following 2 to 3 days. Immunochemical analysis of nonionic detergent-soluble and -insoluble extracts from untreated and TPA-treated cells revealed no differences in vimentin solubility suggesting that TPA induced vimentin phosphorylation does not result in notable vimentin filament disassembly. However the extent of vimentin degradation was more prominent in TPA-treated cultures indicating a higher sensitivity of vimentin to proteolytic degradation. The data show that PKC-mediated phosphorylation of vimentin results in precise spatial and temporal rearrangement of IF which are not associated with altered vimentin solubility, but possibly changes the mechanical properties and interactions of vimentin filaments.

Actins↗
PubMed1991

Phosphorylation of cellular proteins in response to treatment with Clostridium difficile toxin B and Clostridium sordellii toxin L.

Toxin B from Clostridium difficile induces typical morphological changes of cultured cells consisting of rounding up and arborization, which are associated with a dramatic disruption of microfilaments. In this study, we show that toxin L, a cytotoxin produced by bacterial strain Clostridium sordellii, has similar effects on cultured cells including the redistribution of F-actin and of the adhesion plaque protein vinculin. It has been assumed that the mechanisms involved in cytopathic effects of toxin B are related to the function of an unidentified component that regulates the organization of the actin cytoskeleton. We demonstrate that the treatment of cultured astrocytes with toxin B or toxin L alters the incorporation of inorganic phosphate into several proteins. Immunoblot analysis revealed that one of these proteins is tropomyosin. Since tropomyosin stabilizes microfilaments and inhibits the severing activity of gelsolin, the toxin-induced phosphorylation may counteract this inhibition resulting in severing of microfilaments and capping of short filaments. A decrease in the radioactivity associated with intermediate filament protein vimentin was also detected using a monoclonal antibody which specifically recognizes a phosphorylated epitope of vimentin. Since vimentin is an in vivo substrate for various protein kinases, these data are in favor of broad effects of these toxins. Direct measurement of protein kinase C in cells exposed to toxin B or to toxin L did not reveal a significant change in protein kinase C activity. Furthermore, treatments with toxins do not increase cAMP levels, suggesting that toxins do not activate protein kinase A. Although further studies are required to determine the primary target site for the clostridial cytotoxin B and L, our results show that they provoke the alteration in the phosphorylation of cellular proteins.

Actin Cytoskeleton↗
PubMed1990

[Two-dimensional ultrasonic examination of the fetal heart].

The methodology of the two-dimensional fetal echocardiography is described by the basic of the accepted international nomenclature. By their opinion it is necessary that on the 18-20th weeks of gestation the high risk pregnancies in aspect congenital heart disease examined by the well-trained specialists. The indication of fetal echocardiography are listed, too.

Echocardiography↗
PubMed1990

Structure of 2-methoxy-6-nonyl-1,4-benzoquinone, C16H24O3, a synthetic contact allergen related to the naturally occurring primin.

C16H24O3, Mr = 264.36, triclinic, P1, alpha = 4.167 (1), b = 9.658 (1), c = 19.093 (1) A, alpha = 89.66 (1), beta = 87.27 (1), gamma = 79.07 (1) degrees, V = 753.65 (1) A3, Z = 2, D chi = 1.165 Mg m-3, lambda(Cu K alpha) = 1.5418 A, mu = 0.595 mm-1, F(000) = 288, T = 295 K, R is 0.047 for 1682 observed unique reflections. The angle between the quinone ring plane and the mean plane defined by the aliphatic nonyl chain atoms is 17.4 (3) degrees. The average Csp3--Csp3 bond distance and corresponding angle of the side chain are 1.522 (3) A and 113.2 (2) degrees. The average dimensions of the quinone ring are C--C 1.485 (3), C = C 1.337 (3), C = O 1.209 (3) A, C--C--C 118.4 (2), C = C--C 120.8 (2), O = C--C 120.8 (2) degrees. Neighboring molecules form dimers across centres of symmetry which are linked by C--H...O hydrogen bonds, with H(3)...O(4i) 2.42 (4), C(3)...O(4i) 3.29 (2) A, and angle C(3)--H(3)...O(4i) 164 (3) degrees. The dimers are held together by van der Waals forces between the nonyl side chains, and by C(16)--H...O(2ii) hydrogen bonds, with H(163)...O(2ii) 2.56 (4), C(16)...O(2ii) 3.357 (3) A, and angle C(16)--H(163)...O(2ii) 140 (3) degrees [(i) -x, 1 -y, -z; (ii) -1 -x, 1-y, -z].

Allergens↗
PubMed1990

Electroencephalographic vigilance dynamics in multiple sclerosis during an acute episode and after remission.

Twenty-three patients with multiple sclerosis were studied during an acute episode and again 4 weeks later. Whereas the patients' clinical condition improved significantly (Kurtzke DSS: from 3.9 (SD 1.4) to 3.3 (SD 1.5), P less than 0.001), the conventional power spectra of the resting EEG showed no marked changes. Following a 10-min EEG recording under resting conditions the patients performed a visuomotor tracking task, during which a further EEG recording was made. The frequency of the subvigilant non-A epochs of Loomis et al. as calculated for each minute of the resting recording was taken as the basis for evaluating the EEG dynamics of vigilance. A comparison during and after relapse showed differences in the time courses of the numbers of non-A epochs. While the non-A epochs were not time dependent in the acute phase, remission was characterized by a steady increase in non-A epochs across the 10 min of the recording period. This change in the dynamics of vigilance, which approximates a physiological pattern, was accompanied by an improvement in visuomotor tracking performance. Comparison of the power spectra of the EEG recorded during the tracking task showed a bifrontal increase in absolute alpha power during remission.

Acute Disease↗
PubMed1990

Mouth asymmetry upon repeating words. A controlled study of bipolarly depressive patients in the remitted euthymic state.

In view of previous research concerning the lateral bias of hand movements accompanying speech, it was postulated that patients with bipolar depression should differ from normal controls with respect to the asymmetry of mouth opening when repeating speech sounds. This hypothesis was confirmed. Our patient group, consisting of 29 remitted euthymic out-patients, did not show the greater right-sided mouth opening characteristic of the gender-matched normal controls.

Adult↗
PubMed1990

Effect of lithium on the dynamics of electroencephalographic vigilance in healthy subjects.

Eleven healthy male volunteers had EEG recordings before lithium, after 10 days of lithium administration and 2 weeks after discontinuation of lithium. As postulated from previous investigations the typical lithium effect on the dynamics of electroencephalographic vigilance proved to consist of: (1) a decrease of non-alpha segments, i.e., an increase of alpha continuity or an enhancement of alpha activity; (2) an increase of the anterior/posterior ratio of absolute alpha power (AQ); (3) a decrease of the dynamic variability of this alpha anteriorization (CV-AQ). In addition the decrease of dynamic variability of alpha anteriorization was found to be associated with an increase in the amplitude of P1/N1 components of auditory evoked potentials.

Adult↗
PubMed1990

Visuomotor tracking performance and task-induced modulation of alpha activity.

This study is an attempt at clarifying the relationships between defined environmental demands, the efficiency of corresponding visuomotor behaviour and the EEG. We made use of a laboratory paradigm which was devised to closely represent a common man-machine system process, i.e, maintaining of a road vehicle on a predetermined track when squally wind is blowing from the flank. The deviation of the ideal track represents the input signal for the component system man, the compensating steering motion its output signal. This performance is modelled by a visuomotor tracking task which has been developed as a means of ascertaining subtle effects of psychotropic drugs and described elsewhere. We found that the higher the efficiency of test performance, the lower was the task-induced modulation of alpha-activity.

Adult↗
PubMed1990

Oculomotor activity and the alpha rhythm.

From the beginning of clinical use of the EEG until now a close connection with oculomotor activity was assumed and empirically proven. After giving a sketch of the historical development, the issue is extended to the question of a connection between task-related alpha asymmetries and oculomotor activity. In doing so, the concepts of attention and cognition/emotion have to be dealt with. Referring to Kinsbourne, a conceptual framework is outlined which allows a mediation of the different methodical perspectives and thereby the formulation of testable hypotheses.

Alpha Rhythm↗
PubMed1990

Toward a model to explain infant preferences by cerebral emotional asymmetry and hemisphere priming.

This paper argues that the rightward preference observed in most infants can be described as the consequence of two characteristics of the human brain: (1) hemispheric asymmetry of processes underlying emotional experience and (2) priming of cerebral function. Ample research evidence supports each of these propositions, and they have gained increasing, though not universal, acceptance. In combination, they provide a sufficient explanation for several preferences which may have human survival value. They also produce several side-effects in human behavior which can be observed, but which appear to have no survival function.

Brain↗
PubMed1989

Sensation seeking and auditory evoked potentials.

The relationship between auditory evoked potentials (AEP) and the German version of Zuckerman's Sensation Seeking Scale was examined. The slope of the amplitude/stimulus intensity function (N1/P2 component) and the N1 latency were particularly studied, as these variables have been found to be potential predictors of the response to lithium prophylaxis. Thirty-three healthy subjects participated in two testing series on the first day and in a third run 3 weeks later. Binaural clicks at four intensity levels (58, 68, 78, 88 dB HL, ISI 2.1 sec) were presented in randomized order by headphone. Eighty responses were averaged at each intensity level. The pattern of correlation between the German version of the Sensation Seeking Scale and a personality inventory (FPI) supports the validity of the Sensation Seeking Scale. Only a tendency toward steeper slopes of the amplitude/stimulus intensity function (ASF) in high sensation seekers was observed in the first run. However, there was a significant interaction of sensation seeking and the test run. Only high sensation seekers showed an influence of retesting on the slope of the ASF, leading to a decrease of the slope in the second, compared with the first run. This might correspond to the psychological pattern of sensation seeking, which is characterized by a permanent need for new and exciting situations and, at the same time, by a rapid loss of interest in these situations. With regard to the N1 latency, a significant interaction of sensation seeking and lead was found. Low sensation seekers showed longer N1 latencies over the right than over the left hemisphere, a finding that accords with some psychophysiological theories on the relation between asymmetric hemispherical activation and certain psychological constructs. Our results support the view that sensation seeking is a personality feature that is closely related to certain physiological variables.

Adult↗
PubMed1989

The observing subject and psychophysiological research: an epistemological discourse.

Realizing that scientific knowledge was not based on a simple disclosure of reality, but was rather invented and developed in accordance with our own conceptions and prejudices, it should no longer be possible to consider matters as if they existed independently of us 'out there'. Taking as examples the notions of 'memory' and 'information' we try to elucidate the relevance this perspective has with respect to neuro- and psychophysiological research.

Behavior↗