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.     

Foraging strategies ofDrosophila melanogaster: A chromosomal analysis

Two larval foraging strategies inDrosophila melanogaster were identified, rover and sitter. Rovers traverse a large area while feeding whereas sitters cover a small area. The difference between rovers and sitters was analyzed genetically by chromosomal substitutions between isogenic stocks. Differences in larval locomotor behavior (crawling behavior) can be attributed to the second chromosome, the rover strategy being dominant over the sitter strategy. Differences in feeding rate (shoveling behavior) are affected additively by both the second and third chromosomes. Natural populations ofDrosophila larvae were sampled three times over a 2-month period; rovers and sitters were at constant frequencies in these populations. The two foraging strategies are discussed in the light of resource utilization in environments where food is distributed continuously or discontinuously.     

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.

     

Neuron Activity in the Prefrontal Cortex of the Brain in Rats with Different Typological Characteristics in Conditions of Emotional Stimulation

Male Wistar rats were separated according to the emotional resonance method (groups of animals avoiding (altruists) and not avoiding (egotists) the pain cries of partner rats) and neuron activity in the prefrontal areas of the cortex was studied in the right and left hemispheres. Assessments were made of changes in the frequency of nerve cell spike activity (in relation to the baseline activity of neurons in sated animals) in rats subjected to one day of food deprivation and after electrical stimulation of emotionally positive (lateral hypothalamus) and negative (tegmentum of the midbrain) brain structures and after exposure to the pain cries of partner rats. The results of these experiments revealed a series of differences in the cell activities of the two groups of rats. In conditions of hunger, the discharge frequency in the altruists was higher than that in egotists. Cortical neuron responses to positive stimulation were greater than those to negative stimulation in rats of both groups. Intracerebral stimulation produced significantly greater increases in discharge frequency in neurons of both prefrontal areas of the cortex in altruists than in egotists. In both groups of rats, neurons in the right hemisphere responded to emotionally negative stimulation with significantly greater activation than cells in the left hemisphere, while activity in the left hemisphere was greater in conditions of emotionally positive stimulation. Altruists showed significantly greater neuron responses during exposure to pain cries from victim rats in both the right and left hemispheres. The responses of egotists to victim cries were not significantly different from baseline activity levels.     

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.     

Congenic AB mice: A novel means for studying the (molecular) genetics of aggression

Congenic strains (CS) of mice were established to identify genomic regions which are associated with the male behavioral trait isolation-induced aggression (iia). For this purpose the trait was backcrossed for 10 generations onto the genetic background of a closely related, but nonaggressive, strain. Brother/sister matings were subsequently performed for 10 generations. Genomic screening for iia-associated markers was performed via multilocus DNA fingerprinting with a panel of oligonucleotide probes containing simple tandem repetitive motifs. Pools of DNAs from 10 mice each were composed from inbred generations to minimize residual genetic variability in the CS. The representation of iia-associated DNA fingerprint bands was additionally ascertained by investigating the individual mouse genomes constituting the pools. The CS system may allow rational approaches to the behavioral trait aggression, even under various experimental conditions of different environments.     

Treatment of an Autoimmune Disease with “Classical” T Cell Veto: A Proposal

Immune responses protect against infectious diseases and cancers. In normal circumstances, the immune system is tolerant to self. However, under certain conditions this tolerance is broken. The immune system attacks otherwise normal tissue. An autoimmune disease ensues. Strategies are now being sought that remove the pathogenic T cells without affecting other immune functions. Classical veto has been described as an immune suppressive mechanism able to remove T cells in a highly specific and effective manner. The present article briefly reviews the current knowledge on the development of autoreactive T cells and their regulation in the periphery. It describes classical veto, its mechanisms, and its novel applications. Finally, it argues that classical veto can be adapted to treat an autoimmune disease, such as type I diabetes mellitus.     

Effect of muscular work on the motor function of the stomach and duodenum

Summary The effect of muscle work on the gastric and duodenal motor function was studied in dogs.It was observed that the static stress inhibited the hunger contractions of the stomach and duodenum; the inhibitory effect disappeared as the stress ceased. The static muscle work effect was more pronounced in hunger contractions of the stomach than in those of the duodenum. Under the influence of static stress, the periodic hunger contractions of the stomach varied more extensively than its acid and digestive contractions.Presented by Active Member Acad. Med. Sci. USSR V. N. Chernigovsky     

An improved apparatus for the optical recording of contraction of single heart cells

An optical system for measuring changes in cell length during unloaded contractions of cardiac myocytes is described. A one-dimensional video image of a cell is obtained every 4 ms with a linear photodiode array, which is aligned with the longitudinal axis of the cell. The circuit used to process the image from the photodiode array has a variety of features to aid in the accurate determination of the distance between the ends of the cell, i.e. the cell length. First, the video image of the cell is divided into two windows, one encompassing the front edge of the cell, the other encompassing the rear edge. Other cells or debris beyond the cell edges are excluded. Changes in the general light level, for example as a result of debris floating above the cell, have little effect because within the windows the background light level is subtracted from the signals before they are processed further. To detect the cell edges, the system determines when the signals within the windows exceed (front edge) or drop below (rear edge) chosen threscholds, which are different for the front and rear edges. The system has memory and it identifies the rear edge of the cell as the last time the signal falls below the threshold; because of this bright spots within the cell are not mistaken for the end of the cell. The system has hysteresis, which enables it to ignore small fluctuations in brightness around the threshold. The system is easy to use, accurate, readily calibrated, and it has good spatial and time resolution (about 0.25 m and 4 ms respectively).     

Intraspecific variation in the structural organization and redundancy of chloroplast ribosomal DNA cistrons in Euglena gracilis

Summary Chloroplast DNAs from six different laboratory collections of Euglena gracilis strain Z and var. bacillaris were analyzed with restriction endonucleases EcoRI and Bam HI. The most variable portion of the organelle genome is the region containing the ribosomal cistrons. Intraspecific differences occur in both ribosomal DNA cistron number (one or three) and structural organization among those strains designated as strain Z and bacillaris. One culture previously designated as Z is most likely bacillaris.     

Sialadenosis of the parotid gland after long-term treatment with antihypertensive agents (Guanacline)

Summary Long-term treatment of hypertension with the adrenergic blocking agent Guanacline has the side effect of severe pain in the parotid gland which starts on chewing. To gain some insight into this clinical symptom five parotid-gland biopsies were taken from hypertensive patients after treatment with Guanacline and investigated by light and electron microscopy. Biopsies from patients without hypertension and not treated with Guanacline were studied as controls.The morphological alterations consist in swelling of the acini cells, disturbances of secretion with development of light and dark cells and changes in the myoepithelial cells with pycnoses of the nuclei, incorporation of lipid droplets, destruction of myofilaments, and enlargement of the pericellular spaces. The dark cells are characterized by enrichment of secretory granules, vesicular transformation of the endoplasmatic reticulum, and enlargement of the Golgi area with membrane-bound myeline figures. The alterations in the light cells consist in a decrease of secretory granules and spiral transformation of the endoplasmatic reticulum. In both types of cells the secretory granules show a marked variation of configuration, size, optic density and ultrastructure. Changes of the duct system were not observed.The findings are interpreted as neurovegetative sialadenosis after a deficit of sympathetic innervation. These drug-induced changes in the parotid gland demonstrate the importance of the sympathetic nervous system for the synchronization of amylase secretion in the acinic cells. The additional functional loss of the sympathetic innervated myoepithelial cells favors an inversion of the swelling pressure of the acinic cells into the interstitutium with the sensoric nerve fibers.

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Herrn Prof. Dr. H. Bartelheimer, Hamburg zum 65. Geburtstag gewidmet.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

The static load component in muscle work

Summary By citing examples from actual work situations and discussing the concept of muscular endurance and fatigue this paper is intended to provide an account of past and current research on the static component of muscular load during work. By amplitude probability distribution analysis of electromyographic signals it is possible to estimate the static level of muscular load during work. Electromyographic studies of job rotation between different assembly tasks in electronic industries often show that there are quantitatively and qualitatively only small differences in muscular load between different tasks.     

Extramembranous deposits and “membranous” glomerulonephritis

Summary In 15 renal puncture biopsies from 14 patients, electron microscopy revealed extramembranous deposits (EMD) in various developmental stages (or their residues) in glomerular capillaries. Florid EMD exhibited a regular granular substructure as well as a typical localization within the subpodocytal space. Ultrastructurally, a gradual regression of EMD and their incorporation into the basement membrane could be observed. Early florid EMD were found in acute glomerulonephritis or in the nephrotic syndrome persisting for several months, with only discrete to absent membranous changes with light microscopy. Late stages of EMD with predominantly degenerative changes of glomerular basement membranes and apparent membranous thickening in light microscopy, on the other hand, were characteristic of the nephrotic syndrome lasting for several years. At early stages of EMD, long-lasting remission up to clinical healing were observed in a half of the cases studied, whereas at a late membranous stage long-lasting remission took place only once in six cases.     

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.     

Immunological study of HB-Ag carriers

Summary The serum immunoglobulin levels, the presence of circulating autoantibodies, the number of peripheral atypical lymphocytes and the number of DNA and RNA synthesizing mononuclear cells were studied in a group of healthy HB-Ag (australia Antigen) carriers and in a group of healthy HB-Ag negative control subjects.In the HB-Ag carriers, in spite of the persistent antigenaemia, all these immunological findings were normal (as in the control subjects).     

Effect of the degree of myocardial hypertrophy associated with an experimental heart defect on the resistance to altitude hypoxia

Summary Experimental coarctation of the abdominal aorta with constriction of its lumen to one-third of the original diameter was created in 18 albino rats. Four months later various degrees of myocardial hypertrophy developed in the animals with a relative weight of the heart ranging from 0.0033 to 0.0069. In elevation in the barochamber, the altitude ceiling of the animals with a relative cardiac weight below 0.0040, did not differ from the normal one. The altitude ceiling proved to be considerably decreased in animals with a relative cardiac weight of over 0.0040. Analysis of ECG recorded during the elevation demonstrated that in the animals with a considerable myocardial hypertrophy reduced resistance to the acute high altitude hypoxia depended on the reduction of the functional resistance of the heart.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 55, No. 5, pp. 37–40, May, 1963     

The favorite cigarette of the day

The choice of a favorite cigarette smoked during a given day varies considerably. Preferences are related to nicotine dependence and the lifestyles of smokers. In a sample of 5124 smokers, the after-dinner cigarette was chosen as the cigarette which they would miss most, while the next largest proportion of smokers (33%) said that they would miss the first cigarette of the morning most. The latter group scored highest on tests of nicotine dependence. In contrast, infrequent smokers (chippers) chose the after-dinner cigarette.Supported in part by NHLBI Grant HL39770 and California Tobacco-Related Disease Program Grant 1RT-87.     

Oncogenic activity of the BK type of human papova virus in inbred rat strains

Summary The oncogenicity of the human polyomavirus BK (BKV) was tested in newborn inbred rats.It was found that the tumor rate was negatively correlated with the levels of T antibody 3 months after inoculation and the frequency of animals with detectable T antibodies 1.5 months after inoculation.By contrast, no influence of viral HI titers on the tumor rates was found. Thymectomy of animals resulted in most experiments in increased tumor rates. Inoculation with BKV of animals later than 24 hours after birth yielded a decrease of tumor rates.The results obtained suggest that T antibody titers present at a critical time after inoculation are associated with low oncogenicity of BKV.The oncogenicity of BKV was comparatively tested in rat strains possessing the allele l or the allele a, respectively. The oncogenicity was significantly higher in rats with the allele l than in rats with the allele a. Rats with the allele l showed lower T antibody response than rats with the allele a.These differences could be explained by the finding that cells of a origin showedin vitro a higher percentage of T antigen bearing cells than did cells of a strain possessing the allele l. In comparison to previous results obtained with BKV inoculated outbred WISTAR rats, the oncogenicity of comparable BKV doses in inbred rats was generally higher and the latency period of tumor manifestation shortened.     

A Proposed Heuristic for Communicating Heritability Estimates to the General Public, with Obesity as an Example

It is well established that many continuously distributed traits have a heritable component. However, it is often difficult to communicate to the general public the meaning of quantitative estimates of heritability. To address this problem, the present paper introduces a heuristic for communicating heritability to nonscientific audiences. This heuristic involves adopting an extremely simplified model of inheritance and artificially (and somewhat arbitrarily) defining a cutoffs of low environmental risk and affectation status. Using body weight and obesity as an example, we present a table which gives estimates of the proportion of obese persons who are genetically obese assuming varying levels of environmental risk for obesity and relative body weight scores for defining obesity. The resulting statistic may prove useful for lay audiences in understanding a heritability estimate.     

On the terms “reticulosis” and “reticulum cell sarcoma” with regard to the modern concept of the monocyte macrophage system

Summary The terms reticulosis and reticulum cell sarcoma (= malignant lymphoma, histiocytic type) are discussed regarding the modern concept of the monocyte macrophage system which today has replaced the ancient theory of the reticuloendothelial system. The monocyte macrophage system is not independent, but closely related to the myeloid system. Thus, a third blood forming system as was believed in the case of RES does not exist. Phagocytic reticulum cells of the various hematopoietic organs are highly activated monocyte-derived macrophages. All those conditions formerly termed reticuloses have been found to belong either to the myeloid or to the lymphatic system. Considering the reticulum cell sarcomas or malignant histiocytic lymphomas, most of them seem to be of lymphatic rather than of macrophage origin, representing highgrade malignant lymphomas, possibly immunoblastic sarcomas. No relationship between these tumours and the monocyte macrophage system has been established, so far. Therefore, the terms reticulosis and reticulum cell sarcoma should be no longer used in order to avoid confusion, in order to stimulate sufficient diagnostic efforts which will really clarify such cases, and in order to give full credit to modern results of hematopathology.