Causal dimensions of college students' perceptions of physical symptoms

According to attribution theory, controllability, locus, and stability are important dimensions underlying causal explanations. The extent to which these theoretical dimensions underlie lay explanations for physical symptoms is unclear. Accordingly, in this study, attributes relevant to the lay public were empirically derived using a multidimensional scaling (MDS) procedure. Undergraduates (N=194) provided similarity judgments for 18 potential causes of physical discomfort. The MDS analysis yielded a three-dimensional solution. The first dimension captured the distinction between physical and nonphysical causes. The second dimension distinguished either variable versus stable causes or those that are controllable versus uncontrollable by health care professionals. The third dimension differentiated causes under low versus high personal control. These findings empirically confirm the theoretically proposed dimensions of personal control and stability and suggest the utility of considering the physical/nonphysical and controllability by health care professional distinctions in future work on attributions in the health domain.     

Präzisierung der Reizwirkung mittelfrequenter Wechselströme

Zusammenfassung Bei der Mittelfrequenz-Impuls-Reizung ist streng darauf zu achten, daß keine polaritären Reizkomponenten auftreten. Die diesbezügliche Kontrolle wird am besten mit Hilfe des Konvertibilitätstestes vorgenommen, d. h., es darf beim Vertauschen der Zuführungen zu den Reizelektroden weder die Reizschwelle bzw. die Größe des kollektiven Reizerfolges noch dessen Latenzzeit eine signifikante Änderung erfahren. Auf diese Weise wird die Phasenunabhängigkeit des echten Mittelfrequenz-Reizeffektes nachgewiesen.Diesen Anforderungen entsprechen Mittelfrequenz-Impulse, deren Trägerfrequenz über einige wenige Perioden sich aufschaukelt und ebenso wieder abklingt. Demgegenüber sind Mittelfrequenz-Stromstöße mit phasenstarrem Einsatz und Ende nicht unbedingt frei von polaritären Ein- bzw. Ausschalt-effekten, indem sowohl die erste als auch die letzte Trägerperiode einen polaritären Wechselimpuls-Reizeffekt ergeben kann, je nach Phasenlage bezogen auf die wirksame Reizelektrode und Art der Ansprechbarkeit des Reizobjektes (Nerv) auf entsprechend kurze gleitspiegelsymmetrische Wechselimpulse. Für eine echte Mittelfrequenz-Stromstoß-Reizung ist demnach ebenfalls ein Aufschaukeln und Abklingen der Trägerfrequenz über einige wenige Perioden erforderlich.Es besteht ein prinzipieller Unterschied zwischen der echten Mittelfrequenz-Reizung, die phasen -bzw. periodenunabhängig ist und schon früher als apolaritär bezeichnet wurde, und der konventionellen polaritären Reizung, die als polaritäre Komplikation der Mittelfrequenz-Reizung auftreten kann.Diese Präzisierung der Reizwirkung mittelfrequenter Wechselströme wurde angeregt durch zwei im Text erwähnte Publikationen, in denen in keineswegs überzeugender Weise versucht wird, die Mittelfrequenz-Reizung letzten Endes auf das polare Gesetz der Erregung zurückzuführen.

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Summary The particular excitatory action exerted by middle-frequency alternating current can only be revealed if care is taken to eliminate the occurrence of so-called polarity effects. Such effects are produced by the short alternating impulses represented by the first and the last period of a middle-frequency current pulse and are based on the polar law of excitation.In order to prevent such polarity intrusions, it is necessary to increase and decrease the amplitude of the middle-frequency current pulses over a few carrierperiods, or, to use amplitude-modulated middle-frequency impulses of variable shape and duration of envelope.A true middle-frequency excitatory effect is easily demonstrated by resorting to the convertibility test. It will then become evident that stimulation threshold, magnitude as well as latency of response do not change during reversal of the stimulating poles. This means, that no significant phase change of the response with regard to the carrier-frequency occurs when the leads to the stimulating electrodes are commuted, and that, as a result, true middle-frequency effects do not depend upon one particular catelectrotonic variation among the carrier-periods of a middle-frequency current pulse.It can thus be concluded that a fundamental difference exists between true middle-frequency stimulation, which is based on a non-polarity or apolarity principle, and the conventional stimulation of the polar or polarity type.This paper has been written in the hope of dispelling some errors of interpretation (discussed in the text) tending to ascribe the excitatory effects of middle-frequency impulse stimulation to the classical polar law of excitation.

     

Kombinationsformen der Arteriitis

Zusammenfassung Ausgehend von den UntersuchungenRössles zum Formenkreis der rheumatischen Gewebsveränderungen, wird an Hand von 4 eigenen Fällen die Problematik der morphologischen Differentialdiagnose zwischen rheumatischer Arteriitis, Periarteriitis (Panangiitis) nodosa und Thrombangitis obliterans unter Berücksichtigung der Literatur aufgezeigt. Mit der morphologischen Definition der verwendeten Begriffe fibrinöse Entzündung und proliferierende und granulierende Angiitis wird versucht, die drei Formen der Gefäßwandentzündung morphologisch abzugrenzen. Die überschneidungen der morphologischen Symptome und die Kombinationsformen werden aus Beschreibung und Abbildung einschlägiger veröffentlichter Fälle aufgezeigt. Aus dem Nachweis dieses Schrifttumsvergleichs und dem der Differentialdiagnose der 4 eigenen Fälle wird gefolgert, daß bei solchen nicht-klassischen Gefäßentzündungen die Annahme von Kombinationsformen richtiger ist als die immer stärkere Erweiterung des sog. rheumatischen Formenkreises.

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Summary With reference to the investigations ofRössle On the Classification of the Rheumatic Tissue Changes, the problems that are associated with the differential diagnosis of rheumatic arteritis, periarteritis (panangiitis) nodosa, and thromboangiitis obliterans are discussed, exemplified by the report of four cases, and by a review of the literature. By applying the morphological criteria of fibrinous inflammation, proliferative and granulomatous angiitis, an attempt is made histologically to differentiate these three forms of inflammation of the vascular wall. The overlapping of the morphological criteria and the combined forms that mav occur are illustrated in the four cases reported. As shown by comparing the cases in the literature, and as exemplified by the differential diagnosis of the four cases, the inference is made, that with such types of non-classical vascular inflammation, it is better to refer to combined forms than to the more diffuse so-called rheumatic classification.

     

On the existence of a lyotropic and osmotic type of collagen swelling produced by representative electrolytes and anelectrolytes

Summary The influence of NaI, NaCl, urea, glucose and sucrose on venous tissue volume were studied with regard to osmotic (electrostatic and dehydrating) and lyotropic effects. NaI leads to the highest volume increase and to the extreme irreversibility of this change. The tested anelectrolytes cause a decrease of tissue volume over the whole range of concentration with the exception that, beyond 1.0 osM, urea causes an increase. The large reversibility of this increase is pointed out. A strict discrimination between osmotic and lyotropic volume change is questioned.     

Zur Frage der aggregationsbedingten Aktivierungen von Pockenviren

Zusammenfassung Mit Hilfe von Gruppensynergismus-Diagrammen habenSharp und Mitarbeiter drei aggregationsbedingte Pockenvirus-Aktivierungsphänomene demonstriert: anomale Plaquebildung durch Kaninchenpockenvirus, MultiplizitätsAktivierung von Vacciniavirus und Multiplizitäts-Reaktivierung an vorher partiell inaktivierten Viruspopulationen.Die Basis sämtlicher Gruppensynergismus-Diagramme bildet die von den Autoren als allgemeingültig angenommene Proportionalität der Plaquetiter zu den Mengen kinetisch autonomer oder aktiver Viruseinheiten. Anhand eines einfachen Modelles einer aggregierenden Viruspopulation wird nachgewiesen, daß diese Annahme unhaltbar ist und zu der unrichtigen Interpretation führen muß, niedrig aktive Viruspopulationen würden durch Teilchenaggregierung Steigerungen ihrer biologischen Aktivität erfahren.Die Ursachen der Fehlschlüsse werden untersucht und durch Beispiele erläutert.

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Concerning aggregation dependent activations of poxvirusesI. Erroneous conclusions deduced from group synergism diagrams

Summary With the aid of group synergism diagramsSharp and coworkers have demonstrated three activation phenomena of pox viruses, depending on particle aggregation: anomalous plaque production of rabbitpox virus, multiplicity activation of vaccinia virus and multiplicity reactivation of partially inactivated viruses.The authors' basis for all group synergism diagrams is supposed proportionality between the number of plaques and kinetically autonomous or active virus units. Certain shortcomings inherent in this concept can be shown by using a simple model of an aggregating virus population. It can further be shown that this hypothesis leads to the misinterpretation that an increase in virus activity were caused by particle aggregation.The sources of the errors are investigated and are illustrated by examples.

     

Untersuchungen zur Ultrastruktur lympho-epithelialer Thymustumoren unter besonderer Berücksichtigung der sog. „Emperipolesis“

Summary The ultrastructure of eleven thymomas with lymphocytic predominance, one epitheloid cell thymoma and two normal human thymuses is described with special reference to Emperipolesis. All patients have had myasthenia gravis.The normal human thymus consists of three parts: outer cortex, inner cortex, and medulla. The outer cortex contains mainly lymphoblasts and Metcalf's macrophages within the so-called Clark-packet's. The inner cortex consists mainly lymphocytes and interdigitating reticulum cells, and the medulla of epithelial cells, lymphocytes and Hassall's corpuscles.In all cases of lympho-epithelial thymoma and in normal human thymuses there are enormous interdigitations between epithelial (tumor) cells, lymphocytes and macrophages. The epitheloid cell thymomas also show findings which suggest an epithelial cell interaction. We have not found intact lymphocytes inside the cytoplasm of normal and/or tumor epithelial cells, macrophages or interdigitating reticulum cells.The intracellular existence of intact lymphocytes has been termed Emperipolesis by Humble, Jayne, and Pulvertaft, meaning internal wandering. These investigations indicate that Emperipolesis is not an adequate term for cellular interaction in normal human thymuses and thymomas. A false impression of intraepithelial location of thymic lymphocytes is created by two-dimensional sections of complex thymic structure. These ultrastructural studies revealed damage to lymphocytes only in macrophages with lymphocytolysis within these cells and accumulation of numerous heterophagic vacuoles containing fragments of lymphocytic debris within them.

FrÄulein C. Schürmann danke ich für die gute technische Assistenz, Herrn Priv.-Doz. Dr. med. R. W. Ch. Janzen, Neurologische Klinik der UniversitÄt Hamburg, für die klinischen Daten der Myasthenie-Patienten     

Coronary blood flow in rats native to simulated high altitude and in rats exposed to it later in life

Summary In rats exposed to a simulated high altitude of 3500 m for their whole prenatal and postnatal life a severe cardiac hypertrophy develops. In rats born and first staying 5 weeks at sea level and then being exposed to simulated high altitude, only a unilateral right cardiac hypertrophy occurs. In both groups nutritional coronary blood flow was estimated in left ventricle, right ventricle, and septum and was compared with control animals of similar age. Coronary blood flow was measured at hypoxia in all groups. At first cardiac output was determined by the Fick principle, then⁸⁶Rb was applied and the animals were killed after 55 sec. Activity of⁸⁶Rb was measured in both cardiac ventricles and septum and the fractional uptake was calculated. According to Sapirstein (1956, 1958) the distribution of⁸⁶Rb follows the distribution of cardiac output and from both these data the nutritional blood flow to the parts of the heart may be estimated.Cardiac output was similar in rats exposed to simulated high altitude later in life (newcomers) and in control animals, but it was significantly lower in rats born in the low pressure chamber (natives).Fractions of cardiac output supplying cardiac ventricles and septum in rats from both hypoxic groups were significantly higher than in control animals. In the natives they were significantly higher than in the newcomers. The fractions of cardiac output in both newcomers and natives remained significantly higher than those of the control animals, also when calculated per gram of heart tissue.Nutritional coronary blood flow (in ml/min) was higher in both ventricles and septum of the newcomers and in the right ventricle of the natives, and lower in the septum of the natives, when compared with control animals. Coronary blood flow per gram of heart tissue (in ml/min·g) was significantly higher in all cardiac parts of the newcomers, but it was about the same in all cardiac parts of the natives when compared with controls.The importance of observed changes concerning myocardial tissue oxygenation is analyzed by using Krogh's cylindrical tissue model.Presented in part at the XXVIth International Congress of Physiological Sciences, New Delhi, India, October 20–26, 1974.     

Lability in the responses of cells in the auditory cortex of squirrel monkeys to species-specific vocalizations

Summary The activity of 28 cells located mainly in the secondary auditory cortex (A II) of awake squirrel-monkeys, was extracellularly recorded for periods of up to 6 h. Seven different species-specific vocalizations, which were repeatedly presented to the monkey, were used as auditory stimuli. Twenty-six cells responded, at least once, to one or more vocalizations; 22 cells revealed some change in their response (pattern or strength) to at least one vocalization (change in response). Twenty-one cells exhibited a change in the number and/or type of vocalization to which they responded during the recording period (change in selectivity). At some time during the recording period all the responding cells exhibited a change in response and/or a change in selectivity (change in responsiveness). A change in response of a cell to a vocalization did not necessarily exclude a change in selectivity, associated with the same vocalization, later in time and vice-versa. A change in responsiveness to one vocalization was not necessarily correlated with changes in responsiveness to other vocalizations.     

Adaptation and habituation of the vestibulo-ocular reflex in intact and inferior olive-lesioned rats

Summary The gain of the vestibulo-ocular reflex (VOR) of intact pigmented rats was adaptively modified by training protocols that created a visual-vestibular conflict. For training, head restrained animals were oscillated on a turntable in front of an optokinetic pattern projected onto a cylindrical wall. The optokinetic pattern either moved the same amplitude with the animal (in-phase: 0.05 Hz ± 20°/s) or opposite in direction (out-of-phase: turntable and pattern 0.05 Hz ± 10°/s each). VOR responses were tested in darkness before and after each 8 min training period for a duration of 40 min. During out-of-phase training the gain of compensatory eye movements measured in light was close to 2 from the beginning on and the VOR tested in darkness increased in gain progressively from 0.48 (±0.12) to 0.9 (±0.3; P < 0.05) in 5 out of 7 rats. Two rats did not adapt their VOR gain. Phase values decreased slightly by about 10°. During in-phase stimulation compensatory eye movements were almost completely suppressed (gain close to 0) from the beginning on and the VOR tested in darkness decreased gradually in gain from 0.62 (±0.17) to 0.13 (±0.1; P<0.001) in all 6 trained rats. Phase values decreased in parallel from 151° to 119° (P< 0.01). The effectiveness of the in-phase training paradigm in the absence of compensatory eye movements indicates that retinal image slip is the relevant signal for adaptation. In seven rats with histologically verified almost complete inferior olive (IO) lesions (chemically induced at least 45 days prior to training), out-of-phase and in-phase stimulation evoked compensatory eye movements with gains comparable to those in intact rats. VOR parameters measured in darkness were altered with respect to those of control rats. Gain differed extremely between individuals and phase lag re acceleration was in all IO-lesioned rats larger than in intact rats. The time constant of the VOR in response to table velocity steps was significantly longer (17 s ±4) than in intact rats (11 s ± 3). Training did not alter the gain of the VOR in 5 out of 7 IO-lesioned rats. One rat increased its gain during out-of-phase training in the first, but not during a second training session (and not during in-phase training) and another rat decreased its gain during in-phase training (but not during out-of-phase training). These changes in VOR gain might have occurred by chance rather than by learning. The absence of adaptation in IO-lesioned rats can be explained either by the absence of climbing fiber mediated slip signals in the cerebellar cortex or by lesion-induced secondary changes which result in a long-term reduction of the inhibitory efficacy of Purkinje-cells. In the absence of arousing stimuli VOR responses of intact rats exhibit a strong decrement during table oscillations in darkness. Between trials, with the rat at rest, response magnitude recovered spontaneously. Six out of 8 IO-lesioned rats expressed a very similar modification of their VOR gain. These results indicate that the neural mechanisms responsible for adaptive gain decrease during in-phase training and those responsible for a gain decrease during short-term habituation are different.     

Further observations on the morphogenesis of human rotavirus in MA 104 cells

Summary Human rotavirus KUN strain was cultivated in a fetal rhesus monkey kidney cell line, MA 104 cells. Four types of virus particles in cells infected with KUN strain were clearly identified: nucleoid cores, single-shelled particles, double-shelled particles, and membrane band, enveloped particles. Enveloped particles were found only in the thin sections of infected cells. When first visible, the virus precursors appeared at the ribosome free membrane of rough endoplasmic reticulum (RER), increasing in size while simultaneously being coated with nucleocapsid, inner shell. Single-shelled particles were also synthesized within bundles of filaments of viroplasm in the cytoplasma. During subsequent virus maturation two types of budding processes were observed. Double-shelled particles arising at the RER membrane entered the cisternae of the RER through an exocytosis-like process. In contrast, the enveloped particles developed in the cisternae by being completely enclosed with RER membrane, and later during cytolysis released the single-shelled particles. These enveloped virus particles appeared to be the result of inefficient virus maturation at the last stage of outer capsid formation.With 11 Figures