Increased blink rate in acute and remitted schizophrenics.
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Acute Disease↗
Biomedical subjects
K Frick
Publications and source records attributed to K Frick.
Disturbed eye movements guided by visuospatial cues in schizophrenic patients.
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Acute Disease↗
PDGF induces c-myc mRNA expression in MG-63 human osteosarcoma cells but does not stimulate cell replication.
The platelet-derived growth factor (PDGF) modulated growth response of the MG-63 human osteosarcoma cell line, which neither expresses c-sis mRNA nor secretes a PDGF analogue, was characterized. Scatchard analysis demonstrated that the MG-63 cells have 23,000 receptors per cell with a Kd of 5 X 10(-11) M. The receptor became phosphorylated, in a PDGF concentration-dependent manner, when 32P-orthophosphate-labeled cells were treated with PDGF for 3 h at 4 degrees C. The phosphorylated receptor was identified by autoradiography and gel electrophoresis after isolation of the 32P-labeled receptor using a solid-phase monoclonal antibody directed against phosphotyrosine. Binding of the receptor to the antibody was inhibited by 5 mM phenyl phosphate, further suggesting that PDGF stimulated tyrosine-specific receptor autophosphorylation. In addition, treatment of MG-63 cells with PDGF for 3 h at 37 degrees C induced a 7.5-fold increase in c-myc mRNA accumulation as analyzed on Northern gels. However, MG-63 cells grew equally well in either serum-(which contains PDGF) or plasma-(which does not) supplemented medium. Furthermore, PDGF did not stimulate DNA synthesis in growth arrested MG-63 cells, nor did it potentiate DNA synthesis modulated by somatomedin C. Thus MG-63 cells are a naturally occurring cell variant in which PDGF stimulates c-myc expression but does not modulate mitogenesis.
Animals↗
Visuomotor performance of schizophrenic patients and normal controls in a picture viewing task.
The eye movements of 20 partially remitted schizophrenic outpatients (ICD-9) under neuroleptic maintenance medication and those of 20 normal controls were recorded using corneal reflection pupil-center measurement. The visuomotor performance during a 1-min picture viewing task was studied on the basis of several eye movement parameters. Clinical evaluation comprised self-ratings (Frankfort Complaint Questionnaire) and observer ratings (BPRS, CGI, GAS), as well as recording of current daily neuroleptic dosage (mg CPZ). The main results are that schizophrenics differ from normals in their correlational pattern of fixation- and movement-related parameters, reflecting two opposite viewing styles in schizophrenics: staring and extensive scanning. Both styles are differently related to clinical symptomatology. There was no strongly marked relationship with neuroleptic dosage.
Adult↗
Interindividual variability of lithium-induced EEG changes in healthy volunteers.
A placebo-controlled, double-blind study on the effects of lithium on the electroencephalogram (EEG) was performed in 20 healthy volunteers. A reanalysis of the data which previously had been evaluated by factor analysis and other techniques is presented. The aim of this reanalysis is a quantitative reconstruction of visually defined vigilance stages. In 8 of the 10 healthy subjects who received lithium, a "stabilization" of vigilance on a slightly lowered level (i.e., increased continuity of alpha activity and a tendency in the direction of increased alpha anteriorization) could be demonstrated after a 2-week medication period (mean lithium plasma level: 0.65 mmol/l), indicating that in these subjects lithium counteracts the physiological decline of vigilance to be expected under resting conditions. The interpretation of this finding as a reduction of physiological variability, or as a "dynamic restriction," corresponds to findings in other areas of lithium research which can be interpreted in an analogous manner. In two subjects, however, a small decline of vigilance was observed. These two subjects showed an especially pronounced alpha rhythm in their predrug EEG compared with the other volunteers. The authors discuss whether the delineation of different EEG reaction types contributes to the responder problem in lithium research.
Adult↗
Eye movement research with schizophrenic patients and normal controls using corneal reflection-pupil center measurement.
The eye movements of 20 partially remitted outpatient schizophrenics (ICD 9), for the most part receiving neuroleptic maintenance medication, and 20 normal controls were recorded using corneal reflection-pupil center measurement. Performance was investigated on the basis of widely varied measurement parameters during a fixation task and a visual search task (list of letters). Psychopathological data were additionally recorded for the group of patients by means of self and observer ratings, current social adjustment, and neuroleptic dosage. The schizophrenic patients showed the tendency to perform more poorly than the normal controls in the eye movement parameters recorded, and there was marked variation in performance within the group of schizophrenic patients. In particular, various abnormalities in fixation performance were connected differentially with individual psychopathological syndromes and neuroleptic dosage. Connections between fixation performance and search performance were found only within the group of patients. They are interpreted as an indicator of disturbed interhemispheric coordination in schizophrenics. Based upon specific pupillary findings one concludes that the processing load imposed on the attentional system by the search task is different for various schizophrenic subgroups.
Adult↗
A new quantitative approach to the assessment of stages of vigilance as defined by spatiotemporal EEG patterning.
Electroencephalographically oriented research on vigilance needs valid measures for assessing the level of vigilance between wakefulness and sleep. When studying different psychologically, psychopathologically, and pharmacologically induced states, special attention has to be paid to minor alterations of the level of vigilance which are reflected, essentially, in topographical changes of alpha-activity (Stage A). Since vigilance is a dynamic process, brief fluctuations in the range of a few seconds must also be recorded. In our opinion existing methods of quantification do not fully meet these demands. We have, therefore, developed a relatively simple procedure which can be characterized as an attempt quantitatively to reconstruct visually, i.e., spatiotemporally defined patterns of vigilance. The usefulness of this method, which also has certain limitations, has been demonstrated in psychopharmacological studies.
Alpha Rhythm↗
The lateralization of occipital alpha-power under resting conditions in the EEG of healthy volunteers. A state- and a trait-variable.
Using a structural analysis of lateralization of occipital alpha-power in 20 healthy volunteers under resting conditions, a clear vigilance-dependence could be shown for the great majority. In contrast the state of four subjects showed almost no dependence on vigilance. Additional findings according to which these two subgroups also differ in a characteristic manner with regard to various other aspects, especially occipital alpha-quantity and vigilance dynamics, point to a maturational dimension.
Adult↗
Asymmetry of occipital alpha-rhythm under resting conditions: a neurophysiological measure of "hemisphericity".
Using the resting EEGs of 20 healthy subjects in semirecumbent position with eyes closed and left undisturbed, we studied the question whether and, if so, to what extent, lateralization of occipital alpha-rhythm depends on level of vigilance. As a simple indicator of vigilance, the relative alpha-power for each 2-sec. epoch of 02-CZ (occipital right) was calculated. Lateralization was defined as the ratio of absolute alpha-powers in 01-CZ and 02-CZ (occipital left and right). This was also calculated epoch by epoch. The results of individual analysis of data from each subject allowed categorization into 3 types. This typological differentiation obtained quantitatively could be supported by visual pattern analysis. The findings are discussed in relation to the state- vs trait-problem which constantly confronts us when we interpret experimentally obtained functional asymmetries of hemispheres.
Adult↗
Interrelation between changes in the EEG and psychopathology under pharmacotherapy for endogenous depression. A contribution to the predictor question.
With the predictor problem in mind, we studied in-patients with endogenous depression whether relationships exist among the EEG, the therapeutic response, and the severity of psychopathology. We found that clinically defined responders and non-responders differ in respect of their average power spectra calculated for the two occipital regions. In addition, it was shown that there is a statistically significant correlation between the EEG before treatment and the severity of AMP-documented psychopathology after a 4-week treatment period. This correlation was stronger for the left occipital region than for the right.
Amitriptyline↗
[Quantitative microbiologic studies of the sulcus fluid in patients with immunodeficiencies].
Quantitative microbiologic examinations of fluid taken from gingival sulci were carried out with patients suffering from chronic lymphatic leukemia (CLL), i.e. with disturbed immune response, and with healthy subjects. The pathogen count in each case was correlated with the gingival index, the plaque index, the amount of fluid in the gingival sulcus, and the pocket depth. Patients with chronic lymphatic leukemia with gingiva clinically free of inflammation showed one to 20 times more bacterial flora in fluid from the gingival sulcus than fluid from healthy control subjects. The quantitative values tend to equalize only if imflammation is severe. If the pathogen count is considered a function of the amount of plaque or pocket depth, markedly more microorganisms/mm3 of sulcus fluid were found with CLL patients than in the control group. It therefore may be concluded that immunologic reactions contribute decisively to the causation and maintenance of gingivitis with all of its consequences and that these reactions play an important role in the destruction of pathogens found in the region of the gingival pocket.
Aged↗
[Bacterial count in the sulcus fluid of healthy and inflamed marginal gingiva].
Even with a plaque index of 1, peak values of germ count per micronl were found which remained almost constant with plaque increasing up to an index of 3. Germ count and degree of inflammation correlated in the range of the gingival indices 0 to 2. A further intensification of the inflammation showed a significant reduction of germ count per micronl. When studying the relationship between germ count and depth of pocket, the same behavior was observed, starting at a pocket depth of 4.5 mm.
Adolescent↗
Siderophore protection against colicins M, B, V, and Ia in Escherichia coli.
A variety of natural and synthetic siderophores capable of supporting the growth of Escherichia coli K-12 on iron-limited media also protect strain RW193+ (tonA+ ent-) from the killing action of colicins B, V, and Ia. Protective activity falls into two categories. The first, characteristic of enterobactin protection against colicin B and ferrichrome protection against colicin M, has properties of a specific receptor competition between the siderophore and the colicin. Thus, enterobactin specifically protects against colicin B in fes- mutants (able to accumulate but unable to utilize enterobactin) as predicted by our proposal that the colicin B receptor functions in the specific binding for uptake of enterobactin (Wayne and Neilands, 1975). Similarly ferrichrome specifically protects against colicin M in SidA mutants (defective in hydroxamate siderophore utilization). The second category of protective response, characteristic of the more general siderophore inhibition of colicins B, V, and Ia, requires the availability or metabolism of siderophore iron. Thus, enterobactin protects against colicins V and Ia, but only when the colicin indicator strain is fes+, and hydroxamate siderophores inhibit colicins B, V, and Ia, but only when the colicin indicator strain is SidA+. Moreover, ferrichrome inhibits colicins B, V, and Ia, yet chromium (III) deferriferrichrome is inactive, and ferrichrome itself does not prevent adsorption of colicin Ia receptor material in vitro. Although the nonspecific protection against colicins B, V, and Ia requires iron, the availability of siderophore iron for cell growth is not sufficient to bring about protection. None of the siderophores tested protect cells against the killing action of colicin E1 or K, or against the energy poisons azide, 2, 4-dinitrophenol, and carbonylcyanide m-chlorophenylhydrazone. We suggest that nonspecific siderophore protection against colicins B, V, and Ia may be due either to an induction of membrane alterations in response to siderophore iron metabolism or to a direct interference by siderophore iron with some unknown step in colicin action subsequent to adsorption.
Azides↗
Relationship between the transport of iron and the amount of specific colicin Ia membrane receptors in Escherichia coli.
Strains of Escherichia coli K-12 defective in their ability to utilize exogenously supplied iron due to genetic defects in the entF, tonB, fes, or fep gene exhibited elevated levels of the specific outer-membrane receptor for colicin Ia when compared with parental strains. Although entF, fes, and fep strains showed a higher degree of Ia sensitivity than did the parental strains, tonB strains were resistant to colicin action. The colicin insensitivity of tonB strains was not due to hyperproduction of enterochelin. Growth in medium containing 101.8 muM Fe2+ led to a lowering of receptor levels in all the above strains and resulted in decreased colicin Ia sensitivity in all strains except tonB, which was already at maximal resistance. Growth in citrate plus iron (1.8 muM) or in ferrichrome resulted in a substantial reduction in both receptor levels and Ia sensitivity in ent, fes, and fep strains but had no effect on receptor levels in tonB strains. Growth in citrate did not lead to an alteration in receptor levels in a mutant specifically defective in citrate-mediated iron transport. The presence of enterochelin during growth led to a reduction in the number of receptors in the parental and ent strains but not in tonB, fes, or fep strains. Thus, in all cases examined, there was an inverse relationship between the number of colicin receptors per cell and the ability of the strain to take up iron from the growth medium. This suggests that under conditions of iron limitation there is a derepression of colicin Ia receptor biosynthesis. These results may point to a role of the colicin I receptor in iron uptake.
Binding Sites↗
[Psychophysiological studies of EEG, operational performance and the dynamics of vigilance regulation. I. The EEG during performance of Brickenkamp's attention-concentration test (test d 2) (author's transl)].
During the performance of the d 2 test developed by Brickenkamp (standardized test of attention and concentration), occipital EEG activity was registered telemetrically in 10 male students aged 25 to 32 years. Simultaneously, the pencil markings performed by the subjects, indicating the time course of their pattern recognition and discrimination, were recorded by means of a piezo-electrical transducer. The EEG behavior during test performance was evaluated by serial spectral analysis. The analysis of the EEG parameters derived from it (total power, absolute and relative alpha-power) showed that there is a relationship between these EEG measures reflecting the regulation of cortical vigilance and the error rate in the concentration test. While subjects with low error rate present a heightening of cortical arousal focused in the right occipital area, subjects with higher error rate tend to have a higher degree of general cortical activation.
Adult↗
[Psychophysiological studies of EEG, operational performance and the dynamics of vigilance regulation. II. EEG activity and reactivity during tracking performance in a control loop with varying degrees of difficulty (author's transl)].
In ten male students the EEG occipital activity was recorded during a visuo-motor task consisting of pursuit-tracking. The degree of task difficulty varied systematically depending on the modification of the transfer function of control element dynamics. The EEG data were evaluated by serial spectral analysis. The distribution functions of the total power estimates and their minima and maxima reflect the dynamics of the regulation of cortical vigilance and permit to differentiate the degree of effort which corresponds to the varying degree of task difficulty. The study of task-irrelevant acoustically evoked potentials showed that with increasing cortical activation the amplitudes of N1-P2 and P2-N2 are diminished. These results might suggest that evoked potentials induced by task-irrelevant stimuli can serve as indicators of the neuronal capacity available for information processing that is not task-oriented.
Adult↗
[Signal analysis of EEG-changes induced by nomifensin - a new antidepressant (author's transl)].
Ten healthy volunteers received a single oral dose of 100 mg nomifensive, a new antidepressant (tetragtdriusiqyubikube deruvatuve; Hoe 36-984). The drug-induced effects on the EEG were compared with those of placebo. The statistically proved results show that nomifensine causes a distinct shift in vigilance with two different partial processes. After an initially occurring stabilization of the dominant alpha-frequency there appears a polyrhythmic disintegration of the alpha-rhythm with increase of slower and faster frequencies. At the same time a shifting takes place within the beta-range with increasing of 23.5-32.0 Hz-components. Accordingly it is evident that nomifensine results in a typical pharmaco-electroencephalographic profile.
Alpha Rhythm↗