Destabilization of herpes simplex virus type 1 virions by local anesthetics,alkaline pH,and calcium depletion

Summary The infectivity of herpes simplex virus type 1 (HSV-1) was found to be markedly reduced by treating virions with the tertiary amine local anesthetics lidocaine, dibucaine and tetracaine. These treatments induced a characteristic shift in the buoyant density of the HSV-1 particles from a light to a heavy population. HSV-1 virions were unstable at alkaline pH, and alkali treatment caused the same shift in buoyant density. Ca²⁺ stabilized the light population. These results suggest that the physicochemical status of the HSV-1 envelope which is sensitive to the treatments described above plays an important role for the integrity of the virion.     

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.     

Acetylcholine metabolism in the brain of rats treated with vanadyl sulfate and certain phenylacetic acid derivatives

Summary The present work describes the effect produced by phenylacetic acid, phenylethylacetic and diphenylacetic acids (sodium salts) separated and together with vanadyl sulfate on some indices, of acetylcholine metabolism in the rat's brain. Total cholinesterase activity and the free and bound (conditionally) acetylcholine levels served as indices. As shown experimentally the use of phenylacetic acid derivatives is accompanied by reduction of the bound acetylcholine, content, whereas that of free acetylcholine and the total tissue cholinesterase activity remain unchanged. Vanadyl sulfate provokes a significant reduction of the total tissue cholinesterasic activity, but does not change the content of free and bound acetylcholine therein. In conjoint action of the above-mentioned substances, the effects of phenylacetic acid erivatives are supplemented by the anticholinesterase effect of vanadyl sulfate.(Presented by Active Member AMN SSSR S. V. Anichkov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 2, pp. 80–83, February, 1964     

Amygdalar inputs to ADH-secreting supraoptic neurones in rats

Summary Effects of amygdala stimulation on the discharge activity of antidromically identified supraoptic neurosecretory neurones were studied in male rats anaesthetized with urethane. Stimulation of the medial and the basal amygdala produced excitation or inhibition of discharge activity both in phasically firing (phasic) and in continuously firing (continuous) neurones. More phasic neurones were excited than were inhibited after medial amygdala stimulation. On the other hand, fewer continuous neurones were excited by stimulation of the either amygdala area than were inhibited. This difference of responsiveness between phasic and continuous neurones is statistically significant. Synaptic inputs to supraoptic neurosecretory neurones after amygdala stimulation were also observed in rats with a lesion of the stria terminalis. Supraoptic nucleus stimulation activated antidromically 14 of the 336 amygdala neurones tested. Since phasic neurones have been identified as ADH-secreting neurones, it is concluded that ADH-secreting neurones in the rat supraoptic nucleus receive predominantly excitatory synaptic inputs from the medial amygdala and these amygdalar synaptic inputs are mediated by pathways which are at least in part monosynaptic and are not included in the stria terminalis.Supported by the grants nos. 56440079, 56121007 and 56770057 from the Ministry of Education, Science and Culture, Japan     

The distribution of lanthanum in tight junctions of the kidney tubule

Summary The penetration of either ionic or colloidal lanthanum into the tight junctions of different tubular segments of the rat kidney was studied with the electron microscope. After perfusing the tracer through the aorta it was found that ionic and colloidal lanthanum penetrated the tight junctions of both the proximal and distal convoluted tubules, while the junctions of the collecting tubules were free of tracer. An attempt to correlate junctional tightness and electrical resistance in these epithelia is presented.     

Firing characteristics of vestibular nuclei neurons in the alert monkey after bilateral vestibular neurectomy

Summary After destruction of the peripheral vestibular system which is not activated by moving large-field visual stimulation, not only labyrinthine-ocular reflexes but also optokinetic-ocular responses related to the velocity storage mechanism are abolished. In the normal monkey optokinetic-ocular responses are reflected in sustained activity changes of central vestibular neurons within the vestibular nuclei. To account for the loss of optokinetic responses after labyrinthectomy, inactivation of central vestibular neurons consequent on the loss of primary vestibular activity is assumed to be of major importance. To test this hypothesis we recorded the neural activity within the vestibular nuclear complex in two chronically prepared Rhesus monkeys during a period from one up to 9 and 12 months after both vestibular nerves had been cut. The discharge characteristics of 829 cells were studied in relation to eye fixation, and to a moving small and large (optokinetic) visual stimulus producing smooth pursuit (SP) eye movements and optokinetic nystagmus (OKN). Units were grouped into different subclasses.After chronic bilateral vestibular neurectomy (BVN) we have found: (1) a rich variety of spontaneously active cells within the vestibular nuclear complex, which — as far as comparison before and after BVN is possible — belong to all subclasses of neurons functionally defined in normal monkey; and (2) no sustained activity changes which are related to the activation of the velocity storage mechanism; this is especially true for pure-vestibular, vestibular-pause and tonic-vestibular-pause cells in normal monkey which show a pure, pause and tonic-pause firing pattern after BVN. Neurons which are modulated by eye position are, however, modulated with the velocity of slow eye movements with comparable sensitivity during SP and OKN. Retinal slip is extremely rarely encoded. The results of the present study do not directly answer the question why the velocity storage mechanism is abolished after BVN but they suggest that only a small number of central vestibular cells may be inactivated by neurectomy.Supported by SNF grant no. 3.510-0.86     

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.     

Summation and adaptation in stimulation of the motor cortex in adult and newborn animals

Summary In rabbits and their progeny an investigation was made of summation and adaptation of the neurones of the motor cortex; unipolar stimulation was used, and the muscular response recorded. Two types of summation curves were found: exponential and Y-shaped,, and were related to the direct and indirect summation of stimulation. In adults, Y-shaped summation curves were more frequent, whereas in rabbits aged 24 h exponential curves preponderted. We found very little capacity for adaptation at any age.(Presented by Active Member AMN SSSR A. F. Turom) Translated from Byulleten Éksperimental'noi Biologii i Medisiny, Vol. 55, No. 6, pp. 3–7, June, 1963     

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.     

Function dependent changes in the subcellular distribution of high energy phosphates in fast and slow rat skeletal muscles

Function dependent changes in the subcellular distribution of ATP, ADP, creatine phosphate (CrP) and creatine (Cr) in rat fast-twitch gastrocnemius and slow-twitch soleus muscles were studied by fractionation of freeze-clamped and freeze-dried tissue in non-aqueous solvents.During 5 min of isotonic contraction of gastrocnemius muscles the mitochondrial content of total creatine [(CrP+Cr)] decreases by 9.5 nmol/mg total protein whereas there is an increase in extramitochondrial total creatine by 12.3 nmol/mg total protein, indicating a net transfer of 10 nmol total creatine/mg total protein/5 min across the mitochondrial inner membrane.During short-term stimulation (6 s) of gastrocnemius muscles the socalled additionally-bound ADP correlates not only with force (Hebisch et al. 1984) but also with filament overlap. This confirms the previous suggestion that additionally-bound ADP represents actomyosin-ADP-complexes.Following long-term stimulation (10 s), the rate of decay of force is at least two orders of magnitude faster than that of additionally bound ADP. This indicates a decrease of actomyosin-ADP complexes due to formation of myosin-ADP complexes.Short-term stimulation (6 s) of slow-twitch soleus muscles does not lead to any force-dependent change in the content of additionally-bound ADP, similar to the finding in long-term contracting gastrocnemius muscles. Denervation of soleus muscles leads to a decrease in additionally-bound ADP to values comparable to those found in resting fast-twitch gastrocnemius muscles.     

Electromechanical behaviour of human muscles in vertical jumps

Summary The relationships of muscle structure to the potentiation of myoelectrical activity and to the use of prestretching in five lower limb muscles were studied in different vertical jumping conditions. The subjects for the study were six male students, divided according to the muscle fiber distribution in m. vastus lateralis into fast and slow groups. The subjects performed vertical jumps (1) from a static squatting position (SJ), (2) with a preliminary counter movement (CMJ) and (3) after dropping (DJ) from five different heights. Myoelectrical (EMG) activity was recorded from mm. gluteus maximus, vastus lateralis, vastus medialis, rectus femoris and gastrocnemius in each jumping condition and integrated (IEMG) for the eccentric and concentric phases of contact. EMG activity showed potentiation during the eccentric phase of movement when compared to the concentric phase. The fast and slow groups did not differ significantly in this respect, whereas in DJ conditions the relative (% from SJ) height of rise of the center of gravity was greater in the slow than in the fast group. The result indicated that the utilization of elastic energy during jumping was possible better in subjects having a high percentage of slow twitch muscle fibres in their vastus lateralis muscles.     

Somatosensory Evoked Potentials during Natural and Learning Rearrangements of Posture Accompanied by Limb Elevation in Dogs

Changes in the functional state of the sensorimotor cortex associated with reorganization of the natural pattern of postural rearrangement before limb elevation (the diagonal pattern and of an artificial rearrangement (the unilateral pattern) were studied in dogs. The state of cortical structures on postural rearrangement was assessed in terms of the pattern of somatosensory evoked potentials produced in response to stimulation of the forelimb during postural preparation of the animal for elevating the hindlimb (acquired avoidance response to a sound signal). Evoked potentials during the natural postural preparation (the diagonal pattern) were compared with those during the altered pattern of postural preparation (the unilateral pattern), this preparation taking place prior to elevation of the limb. Controls consisted of evoked potentials in the resting state. Decreases were seen in the latencies and amplitudes of most components of evoked potentials during postural rearrangement. In general, changes in evoked potentials were less marked in the unilateral pattern than in the diagonal pattern, though the differences were significant only for the amplitude of the first negative component. Changes in evoked potentials were similar regardless of whether the supporting forces of the limb to which the test stimulus was applied increased or decreased during postural rearrangement. It is suggested that differences in evoked potentials may reflect changes in the interaction between neuronal populations within the sensorimotor cortex during reorganization of the pattern of postural rearrangement associated with learning.     

Disturbance of delayed match-to-sample in macaques by tetanization of anterior commissure versus limbic system or basal ganglia

Summary Three pig-tailed macaques were trained to select (match) from a pair of colored images that which they had seen (sample) and responded to 5–15 s previously. The anterior commissure (AC) and/or its radiation, various loci in basal ganglia, hippocampal formation and control areas, (splenium of corpus callosum, precentral gyrus, insular cortex), totalling 40 loci, were each tetanized for 4 s during presentation of the sample image, during the delay period, or when the monkey was required to select the matching image. For several loci in the hippocampal formation tetanization at any phase of the task reduced matching to chance levels and gave evidence of electrical after-discharge; but other comparable hippocampal loci had little or no effect. Response to sample or match stimuli were absent during tetanization of basal ganglia or anterior commissure. When finally made, upon cessation of tetanization, responses were equally correct for basal ganglia and control sites, but for AC were at chance levels.     

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.     

The structure of a feline picornavirus and its relevance to cubic viruses in general

Summary Using the negative staining technique the pattern of subunits (capsomeres) on the surface of cubic viruses can be revealed as either white projections against a dark background (posimeres),e.g. adenoviruses, or as dark hollows surrounded by a lighter rim (negameres),e.g. reoviruses. A symmetrical pattern of 32 negameres has been demonstrated for some recently isolated feline picornaviruses and from an extension of these studies, based on radiographs of foam-rubber models, it is postulated that posimere or negamere formation may be obtained by relatively minor variation of a basic structure unit.     

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     

Influence of sodium ions on the regulation of frog myocardial contractility

Summary In frog atrial bundles it is possible under voltage clamp conditions to distinguish between a phasic component of mechanical response, depending on Ca⁺⁺ influx, and a slow component, which does not directly depend on the presence of extracellular Ca⁺⁺ (Vassort et Rougier, 1972). The present results suggest that the slow component can be abolished by substituting LiCl for NaCl. The hypothesis is advanced that a displacement of Ca⁺⁺ by Na⁺ from some intracellular binding sites by a variation of membrane potential or [Na]_i causes the slow phase of contraction.Furthermore, relaxation during the phasic component is markedly slowed when LiCl or sucrose is substituted for NaCl. This may indicate that a Na⁺-Ca⁺⁺ exchange across the surface membrane is essential for relaxation.A Na⁺-Ca⁺⁺ exchange (a Ca influx linked to a Na efflux in this case) may account for the contractures elicited by Na-free media.This work constitutes a part of Doctorat es Sciences N^o CNRS: AO 66 71. It was supported in part by contract DGRST, Paris, France.     

Complaints of Fatigue: Related to Too Much as Well as Too Little External Stimulation?

Fatigue has been acknowledged as a widespread problem associated with a variety of factors. In the present paper, we attempt to explain fatigue complaints on the basis of Pennebaker's (1982) competition of cues notion. Competition of cues suggests that both extremely low and extremely high levels of external stimulation in daily life may be related to relatively higher frequencies of complaint. The dimensional structure of external stimulation is first explored and then the shape of the relation between external stimulation (i.e., stimuli perceived in daily life) and fatigue was studied in a sample of 777 general-practice patients. Other risk factors for fatigue and moderating factors are also taken into consideration. Results show that quantity and quality of external stimulation can be distinguished. Both high quantity (high experienced overload) and low quality (low attractiveness of external stimulation) are related to higher fatigue frequencies. Experienced overload is a particularly strong predictor, in addition to perceived health of fatigue complaints. It is concluded that the quality-quantity model for understanding fatigue proposed here highlights psychological factors important for any theoretical framework of fatigue.     

Biophysical studies of teschen disease virus (Talfan strain)

Summary Studies have been made of the heterogeneity of infectivity and CFA in Teschen virus (Talfan strain) suspensions. Most of the infectivity was contained in two components of densities 1.46 gm./ml. and 1.35 gm./ml. The physical, chemical and immunological properties of these components have been compared. It was possible, however, to convert a large proportion of 1.46 component to 1.35 component by treating the 1.46 component with sodium dodecyl sulphate. This would indicate that the 1.46 component was a complex formed between the infective particles and cellular debris.Further studies on the growth characteristics and electron microscopy of the virus have been made.     

The Involvement of Dopamine in Strengthening Cortical Signals Activating NMDA Receptors in the Striatum (a hypothetical mechanism)

A possible mechanism is proposed for the enhancement/weakening of those cortical signals in the cortex-basal ganglia-thalamus-cortex neural network which induce/do not induce opening of NMDA channels in the spiny neurons of the striatum and which can be regarded as strong/weak in terms of this measure. The mechanism is based on the modulatory influences of dopamine on changes in the efficiency of corticostriatal inputs. In the absence of dopamine, relative increases in the intensity of strong (weak) cortical signals can lead to the induction of long-term potentiation (depression) of corticostriatal synapses. In this case, because of the differently directed influences on thalamic cells of signals passing via strionigral and striopallidal cells, strong signals at the output of the thalamus are weakened, while weak signals are strengthened. Activation of dopamine D₁ (D₂) receptors on strionigral (striopallidal) neurons may facilitate increases in the extent of long-term potentiation/depression (decreases in the extent of long-term potentiation/depression or induction of long-term potentiation/depression). The consequence of this is that strong signals at the output of the thalamus can be strengthened synergistically, while weak signals cab be weakened synergistically. Background cortical signals evoking tonic release of dopamine in the striatum can decrease strengthening because of weakening of the modulatory influence of dopamine on the modification of corticostriatal synapses.