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PubMed1983

Head injury in man and experimental animals: clinical aspects.

Clinical studies have demonstrated that, with regard to death, the two worst types of head injury are subdural haematoma (SDH) and diffuse axonal injury (DAI). These two have different mechanisms of causation; SDH occurs much more commonly in non-vehicular injuries, especially falls, while DAI is caused, almost exclusively by vehicular mechanisms. The production of these two types of injury in non-impact acceleration models helps to explain these causal differences, but also shows that both injuries share a common mechanical cause, differing only in degree. SDH is due to vascular injury that is caused by relatively short duration angular acceleration loading at high rates of acceleration. These are the circumstances that occur in falls where the head rapidly decelerates because of impact to firm, unyielding surfaces. DAI is also due to angular acceleration of the head, but occurs most readily when the head moves coronally and it only occurs when the acceleration duration is longer and the rate of acceleration lower than conditions that produce SDH. These conditions are met in vehicle occupants where impact to deformable or padded surfaces lengthens the deceleration and decreases its rate. In DAI the principal mechanical damage is to the brain itself (mainly to axons) while in SDH the primary damage occurs to surface blood vessels. Now that models of the two most important types of head injury have been created in the laboratory, it is hoped that a better understanding of their pathophysiology will result in new strategies to affect protection from their occurrence and in improved treatment when they do occur.

Accidents, Traffic↗
PubMed1996

Effect of density on age-specific mortality in Drosophila: a density supplementation experiment.

Age-specific mortality rates were studied at two adult density levels in four inbred lines of Drosophila melanogaster. In experimental populations, adult densities were maintained at constant levels throughout the experiment by replacing dead flies with live, marked mutants. In control populations, densities declined naturally as the cohorts aged. For all experimental populations the best mortality model is the two-stage Gompertz model, with slower mortality acceleration at older ages. Flies in the experimental populations generally lived longer than flies in control populations, regardless of sex, genotype, or initial density level. The data demonstrate that deceleration of age-specific mortality rates at older ages is not caused by declining cohort densities. Mortality deceleration is a real phenomenon that raises serious questions about the evolution of senescence.

Age Factors↗
PubMed1990

Coordination of legs during straight walking and turning in Drosophila melanogaster.

Leg coordination of Drosophila melanogaster was studied using frame-by-frame film analysis. 1. For fastest walking alternating tripod coordination is observed which slightly deviates towards tetrapody as a function of step period. During acceleration or deceleration legs may transiently recover in diagonal pairs. 2. Mean step length increases with step frequency. 3. Mean recovery stroke duration increases with step period and plateaus beyond a period of about 110 ms. Middle legs recover significantly faster than others. 4. Ipsilateral footprints are transversally separated. 5. Walking is usually initiated in tripod coordination (frequently in combination with a turn), otherwise in an accelerating sequence which rapidly shifts towards tripod pattern. Flies can stop abruptly or decelerate over about one metachronal wave. 6. Short interruptions in walking are observed. Legs interrupted during swing phase stay lifted and finish recovery thereafter. 7. Slight changes in walking direction are obtained by altering step lengths only. Tight turns are composed of two or three phases with backward, zero and forward translatory components. In fast turning tripod coordination is maintained. Otherwise body sides can decouple widely. In all turns numbers of contralateral metachronal waves were equal. Results are compared to those for other walking insects and their relevance in screens for locomotor mutants is discussed.

Animals↗
PubMed1996

Grip reorganization during wrist transport: the influence of an altered aperture.

Past studies have examined the coupling of reach and grasp components during prehensile movements. Many of these studies have supported the view that these components reflect the output of two parallel, though temporally coupled, motor programs. When the grip aperture is Altered prior to the onset of prehension from its usual, normally flexed position to one of maximal finger extension, our previous work has shown that the grasp component appears to reorganize itself during the reach. This reorganization, consisting of a brief closing and reopening of the grip aperture, only slightly influenced the temporal components of the wrist transport. The present experiment continues this research theme by examining the characteristics of grip aperture reorganization through the comparison of the kinematics of prehension components during movements to two different size objects under normal and Altered grip aperture conditions. It was hypothesized that if the grip reorganization is task dependent it should be related to object size. The experiment found that in the Altered grip condition reorganization did occur, as indicated by a slight closing and reopening of the aperture without influencing the transport of the wrist. The amplitude of and the time to the observed inflection point in the aperture time course were related to object size. The velocity of grip closing for the large object showed double peaks, with the first substantially smaller than the second. Moreover, for the small object, the velocity of grip aperture closing also was double peaked, but the difference between peaks was less pronounced. These changes in grip velocity suggest that the grip reorganization is related to object size. No effect of Altered aperture was observed on the transport component. For both object sizes in the Altered condition, the final peak velocity of grip aperture was statistically significantly correlated with transport time and time to peak deceleration. In contrast, such correlations were not observed for the initial peak velocity of the grip aperture. Furthermore, time to maximum grip aperture was correlated with both time to peak wrist velocity and time peak to wrist deceleration. Thus, as the reach progressed toward the object, the grip and transport components became more interdependent. The results are consistent with the notion that, when a well-practiced, coordinated act such as prehension is confronted with an Altered grip posture at the onset of the reach, the grip can be reorganized during the transport to preserve the relative timing between them. Thus these data add to the growing awareness that not only is there temporal coupling between the reach and grasp components but that these components may be integrated by higher-order control mechanism.

Adult↗
PubMed1996

Reaching to ipsilateral or contralateral targets: within-hemisphere visuomotor processing cannot explain hemispatial differences in motor control.

Aiming movements made to visual targets on the same side of the body as the reaching hand typically show advantages as compared to aiming movements made to targets on the opposite side of the body midline in the contralateral visual field. These advantages for ipsilateral reaches include shorter reaction time, higher peak velocity, shorter duration and greater endpoint accuracy. It is commonly hypothesized that such advantages are related to the efficiency of intrahemispheric processing, since, for example, a left-sided target would be initially processed in the visual cortex of the right hemisphere and that same hemisphere controls the motor output to the left hand. We tested this hypothesis by examining the kinematics of aiming movements made by 26 right-handed subjects to visual targets briefly presented in either the left or the right visual field. In one block of trials, the subjects aimed their finger directly towards the target; in the other block, subjects were required to aim their movement to the mirror symmetrical position on the opposite side of the fixation light from the target. For the three kinematic measures in which hemispatial differences were obtained (peak velocity, duration and percentage of movement time spent in deceleration), the advantages were related to the side to which the motor response was directed and not to the side where the target was presented. In addition, these effects tended to be larger in the right hand than in the left, particularly for the percentage of the movement time spent in deceleration. The results are interpreted in terms of models of biomechanical constraints on contralateral movements, which are independent of the hemispace of target presentation.

Adult↗
PubMed1992

Kinematic models and human elbow flexion movements: quantitative analysis.

The smoothness with which movements are customarily performed has led Hogan (1984) to formulate a model for trajectory planning by the central nervous system in which the goal is to maximize smoothness, one measure of which is the integrated mean squared magnitude of jerk (jerk cost). We tested the applicability of this minimum-jerk model to one-joint goal directed movements performed by human subjects at different speeds and amplitudes, by comparing kinematic parameters and the jerk cost predicted by the mathematical model with values calculated from experimental data. We also tested a higher order, minimum-snap kinematic model. Normal subjects performed elbow flexions of 5 to 50 degrees "as rapidly and accurately as possible" and also at slower speeds. The boundary conditions of both models were adjusted to account for the failure of subjects to produce movements which reached equilibrium precisely at the target (so that acceleration and velocity reached zero together). Typically, fast movements (less than 300 ms duration) were fairly symmetric in that the durations and amplitudes of acceleration and deceleration were approximately equal; slower movements (greater than 300 ms) were asymmetric with strong, brief acceleration peaks and broad, slow deceleration peaks. In fast movements, the calculated jerk cost was consistently higher than predicted by the minimum-jerk model; a good fit to all kinematic parameters was provided by the minimum-snap model (a seventh-order polynomial). Neither model consistently predicted the trajectories of slower movements. We conclude that muscle/limb dynamics can account for the success of the minimum-snap model with fast movements, and that there is no evidence of planning for maximal smoothness in slower movements.

Brain↗
PubMed1994

Movement-related phasic muscle activation. III. The duration of phasic agonist activity initiating movement.

To test the hypothesis that phasic muscle activation is related to the acceleration-deceleration characteristics of the resulting movement, we examined the relation between the duration of the acceleratory phase of a variety of movement types and the duration of the phasic muscle activity producing the acceleration (the initial agonist burst, AG1). Movements of five types were studied: (1) step-tracking movements of different amplitudes (10-90 deg) and durations (200-800 ms), (2) movements of the same amplitude (40 deg) and duration (600 ms) varying only in their symmetry ratio (SR, ratio of acceleration to deceleration durations), (3) movements in which acceleration duration was changed while acceleration magnitude was held constant, (4) oscillatory movements of different frequencies and peak amplitudes, (5) step-tracking movements against different inertial loads. Subjects made movements about the elbow joint in the horizontal plane. Surface electromyographic (EMG) activity was recorded from the biceps and the lateral head of the triceps muscles. Under all movement conditions tested and with acceleration duration ranging from 100 to 500 ms, acceleration duration varied linearly with the duration of AG1. Correlation coefficients for the linear regression lines ranged from 0.8 to 0.99. The slope of the best fit linear regression lines ranged from 0.5 to 1.6 and tended to be higher for extensions than flexions. The variations in slope may arise from differing mechanical properties of the biceps and triceps muscles, as well as from active forces produced in the antagonist. AG1 duration was unchanged by inertial loading when subjects kept acceleration duration constant. If subjects responded to an increase in inertial load with an increase in acceleration duration, there was a corresponding increase in AG1 duration. The data demonstrate a general relation between one characteristic of muscle activation (AG1 duration) and the resulting movement. The linear form of the relation is invariant across movement amplitude (range 10-90 deg), speed, duration (range 200-800 ms) and temporal profile (SR range 0.3-2.7), and is also independent of movement type (step, oscillatory). Such a general and simple relation between EMG and movement suggests that, at least to a first approximation, the nervous system can rather simply determine the muscle activation patterns needed to produce movements with desired characteristics.

Acceleration↗
PubMed1994

Binocular vision and the on-line control of human prehension.

The contribution of binocular visual feedback to the kinematics of human prehension was studied in two related experiments. In both experiments, the field of view of each eye was independently controlled by means of goggles fitted with liquid-crystal shutters. While wearing these goggles, which permitted either a binocular or a monocular view of the world, subjects were required to reach out and grasp a target object, which varied in size and position from trial to trial. In experiment 1, two viewing conditions were used. In one condition, binocular vision was available throughout the entire trial; in the second condition, the initial binocular view was replaced by a monocular view after the reaching movement had been initiated. When only monocular feedback was available, subjects showed a prolonged deceleration phase, although the time they spent in contact with the object was the same in both conditions. In experiment 2, monocular vision was available throughout a given trial in one condition and was replaced by binocular vision upon movement initiation in the second condition. Subjects in this experiment also displayed a prolonged deceleration phase in the monocular feedback condition relative to their performance in the binocular feedback condition. Unlike experiment 1, however, allowing only monocular feedback resulted in an increase in the amount of time subjects spent in contact with the object. Moreover, the object contact phases under the two conditions of experiment 2 were much longer than those observed in experiment 1, in which subjects received initial binocular views of the object.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Principles for learning single-joint movements. I. Enhanced performance by practice.

This study investigated changes in myoelectric and mechanical variables for movements made "as fast as possible" as a function of practice in the context of the dual-strategy hypothesis of motor control (Gottlieb et al. 1989b). Five male subjects made 1400 rapid elbow flexion movements in ten blocks of 20 trials over seven experimental sessions. Improved performance was defined as increased peak movement velocity, decreased peak velocity variability, increased acceleration and deceleration, a proportionately greater increase in peak deceleration than peak acceleration, and greater consistency in terminal location. The changes observed over experimental sessions were very similar to (but larger and more consistent than) those seen for the first experimental session, with the partial exception of the timing of the antagonist electromyogram (EMG). In general, the increases in the values of the measured mechanical variables covary with myoelectric measures in the same way as when subjects are asked to intentionally change speed in accordance with the rules of the speed-sensitive strategy (Corcos et al. 1989). However, there are differences between subjects in the extent to which speed changes can be attributable to the agonist muscle, the antagonist muscle, or in the timing between the muscles. In one of the five subjects, the latency of the antagonist EMG decreased over blocks on the 1st day but increased over experimental sessions and was consequently activated proportionately later in the movement. This suggests that extended practice can give at least some subjects flexibility in modifying the motor programs that underlie movement.

Adult↗
PubMed1995

Kinematic analysis of reaching in the cat.

The present study examines the kinematic features of forelimb movements made by cats reaching for food in horizontal target wells located at different heights and distances. Wrist paths consisted of two relatively straight segments joined at a "via-point" in front of the aperture of the food well. In the initial lift phase, the paw was raised to the via-point in front of the target. In the second, or thrust phase, the paw was directed forward into the food well. During the lift, the paw was moved toward the target primarily by elbow flexion, accompanied by a sequence of biphasic shoulder and wrist movements. Thrust was accomplished primarily by shoulder flexion while the wrist and the paw were maintained at near-constant angles. The animals varied the height of the reach primarily by varying elbow flexion with proportional changes in elbow angular velocity and angular acceleration and with corresponding variations in wrist speed. Thus, cats reached for targets at different heights by scaling a common kinematic profile. Over a relatively large range of target heights, animals maintained movement duration constant, according to a simple "pulse-height" control strategy (isochronous scaling). For reaches to a given target height, animals compensated for variability in peak acceleration by variations in movement time. We examined the coordination between the shoulder and the wrist with the elbow. Early during the lift, peak shoulder extensor and peak elbow flexor accelerations were synchronized. Late during the lift phase, wrist extensor acceleration was found to occur during the period of elbow flexor deceleration. We hypothesize that these linkages could, in part, be due to passive mechanical interactions. To determine how the angular trajectories of the different joints were organized in relation to target location, we plotted joint kinematic changes directly on the wrist and MCP joint paths. These plots revealed that for all target heights and movement speeds, wrist extensor deceleration occurred at approximately the same spatial location with respect to the target. This analysis also demonstrated that the second phase of MCP flexion occurred when the paw was below the lower lip of the food well, while the subsequent extension occurred after the tip cleared this obstacle. During thrust, wrist and MCP angles were maintained, reflecting the need to align the paw within the food well. Our findings suggest that cats plan the reaching phase of prehension as a sequence of discrete movement segments, each serving a particular goal in the task, rather than as an single unit.

Animals↗
PubMed1993

Responses of intra-abdominal pressure and abdominal muscle activity during dynamic trunk loading in man.

The purpose of this study was to determine and compare interactions between the abdominal musculature and intra-abdominal pressure (IAP) during controlled dynamic and static trunk muscle loading. Myoelectric activity was recorded in six subjects from the rectus abdominis, obliquus externus, obliquus internus, transversus abdominis and erector spinae muscles using surface and intra-muscular fine-wire electrodes. The IAP was recorded intra-gastrically. Trunk flexions and extensions were performed lying on one side on a swivel table. An adjustable brake provided different friction loading conditions, while adding weights to an unbraked swivel table afforded various levels of inertial loading. During trunk extensions at all friction loads, IAP was elevated (1.8-7.2 kPa) with concomitant activity in transversus abdominis and obliquus internus muscles--little or no activity was seen from rectus abdominis and obliquus externus muscles. For inertia loading during trunk extension, IAP levels were somewhat lower (1.8-5.6 kPa) and displayed a second peak when abdominal muscle activity occurred in the course of decelerating the movement. For single trunk flexions with friction loading, IAP was higher than that seen in extension conditions and increased with added resistance. For inertial loading during trunk flexion, IAP showed two peaks, the larger first peak matched peak forward acceleration and general abdominal muscle activation, while the second corresponded to peak deceleration and was accompanied by activity in transversus abdominis and erector spinae muscles. It was apparent that different loading strategies produced markedly different patterns of response in both trunk musculature and intra-abdominal pressure.

Abdomen↗
PubMed1984

Effects of auditory stimulus timing in the respiratory cycle on the evoked cardiac response in man at rest.

The present experiments were carried out in 21 healthy adults to study the effects of auditory stimulus timing within the respiratory cycle on evoked cardiac response. The stimulus (80 dB white noise) was started by the first and finished by the second R-wave after change in respiratory phase, and presented in different series in either early inspiration or early expiration. The spirogram and eight sequential interbeat intervals (IBI) after respiratory phase change were recorded. The mean of IBI and standard deviation (SD) were calculated separately for each IBI of 20 trials for each subject, during both the prestimulus and poststimulus phases. The stimulus effects were expressed as changes from prestimulus conditions, in terms of delta IBI and delta SD. The mean of each of the eight IBI and its SD were found to vary consistently in the same direction, i.e., SD increased with increasing mean IBI. Stimulation during early inspiration did not produce any effect during this respiratory phase. It was not before the beginning of the following expiration that a significant deceleration was evoked, which was associated with an enhanced delta SD, whereas stimulation during early expiration promptly evoked a biphasic cardiac response of the deceleration - acceleration pattern and an increase and decrease in delta SD, respectively. While SD was found to be a function of age, no such finding was obtained for delta IBI and delta SD. These results are discussed in terms of the "vagal gating" hypothesis.

Acoustic Stimulation↗
PubMed1985

Growth in Cushing syndrome.

Pre- and post-operative growth was analysed in eight children with Cushing syndrome. Six children had Cushing's disease; three of them were treated by bilateral adrenalectomy and three by transphenoidal pituitary adenectomy. One child had an adrenocortical adenoma and another primary adrenocortical nodular dysplasia. The typical cushingoid habitus was not always present during hypercortisolism. In contrast, abnormal deceleration of longitudinal growth and increase in relative weight were constant. The slowing of growth started 0.2-5.1 years before diagnosis. In four children these changes concurred. In three others the excessive weight gain preceded the slowing of growth, by 2.5-7.0 years. In one patient the deceleration appeared first; this was a girl with concomitant coeliac disease. This pattern of growth change occurring before (normal slowing of growth in) late puberty should raise the possibility of hypercortisolism. There was a suggestion of a better growth recovery in Cushing disease after pituitary adenectomy than after bilateral adrenalectomy.

Adolescent↗
PubMed1985

Interaction between mucociliary transport and the ciliary beat of chicken nasal mucosa.

We studied the relationship between the mucociliary transport time and the ciliary beat frequency in the chicken nares following water deprivation and topical administrations of cocaine, atropine, and Newcastle disease virus (NDV). Dehydration produced progressive decelerations of mucociliary flow but not ciliary beat frequency. In vivo 5% cocaine resulted in decreased sinus mucociliary transport time, while application of 20% cocaine to in vitro tissues caused ciliary paralysis within 5 min. Topical atropine was seen to affect both mucociliary flow and the ciliary beat frequency. NDV infection induced deceleration of the turbinate clearance time after 72 h, but did not change ciliary beat frequency. By day 12, mucociliary flow remained unchanged although ciliary beat frequency decreased significantly. Our results support the general concept that mucus is more important than are the cilia in normal nasal mucociliary function.

Animals↗
PubMed1976

Noradrenaline synthesis and utilization: control by nerve impulse flow under normal conditions and after treatment with alpha-adrenoreceptor blocking agents.

The changes in the synthesis and utilization or noradrenaline cranial and caudal to an acute section of the rat spinal cord have been used to investigate the importance of nerve impulses for these processes. 1. Cranial to a lesion of the spinal cord, the alpha-methyltyrosine-induced disappearance of noradrenaline was accelerated by the alpha-adrenoreceptor blocking agents yohimbine (10 mg/kg), piperoxan (60 mg/kg) and tolazoline (50 mg/kg). In the absence of nerve impulses caudal to a lesion of the spinal cord, this disappearance was decelerated as compared to that cranial to the lesion and it was not influenced by the three alpha-adrenoreceptor blocking agents. 2. The nialamide-induced accumulation of normetanephrine in the whole brain was increased by phenoxybenzamine (20 mg/kg) and yohimbine whereas it was decreased by the alpha-adrenoreceptor stimulating agent clonidine (0.1 mg/kg). The effect of clonidine was completely antagonized by yohimbine, but not by phenoxybenzamine, giving further evidence for the view that clonidine and yohimbine have a stronger effect than phenoxybenzamine on the alpha-adrenoreceptors regulating the release of noradrenaline induced by nerve impluses. 3. The accumulation of Dopa after decarboxylase inhibition cranial to a lesion of the spinal cord was accelerated by yohimbine, piperoxan and tolazoline, but not significantly affected by phenoxybenzamine and haloperidol (10 mg/kg). In the absence of nerve impulses caudal to a lesion of the spinal cord, the popa accumulation was decelerated as compared to that cranial to the lesion and it was not influenced by the former three alpha--adrenoreceptor blocking agents as well as by clonidine. 4. The results show that the synthesis and the utilization noradrenaline normally, as well as the accelerations of these processes by alpha-adrenoreceptor blocking agents, are dependent on nerve impulses. The stimulation of the synthesis and utilization of noradrenaline by nerve impulses might by influenced via the activity of teh alpha-adrenoreceptors located either on the nerve terminals or on the cell bodies or on both parts of the noradrenergic neurones. In the absence of nerve impulses, a receptor-mediated feedback mechanism similar to that described for the synthesis of dopamine does not appear to regulate the synthesis of noradrenaline.

Adrenergic alpha-Antagonists↗
PubMed1988

Ultrastructural features of a brain injury model in cat. I. Vascular and neuroglial changes and the prevention of astroglial swelling by a fluorenyl (aryloxy) alkanoic acid derivative (L-644,711).

We present qualitative and quantitative ultrastructural observations on the changes induced in neuroglia and blood vessels of gray matter of cat brain by an experimental acceleration-deceleration injury which, when used alone, causes negligible morbidity and mortality, but, when combined with systemic hypoxia, leads to coma and delayed death in approximately 50% of experimental subjects. An increase in the proportion of neuropil occupied by astrocytic cytoplasm is detectable qualitatively in layer Vb of pericruciate cortex 20 min after injury without hypoxia, and is maximal (22%, as measured morphometrically, vs 11.4% in controls) 40 min afterward. Near-normal values (14.1%) are obtained 100 min following the insult. If trauma is succeeded 40 min later by a 60-min period of hypoxia, there is prolongation of astrocytic edema and other neuroglial accompaniments of the traumatic lesion, such as aggregation of nuclear nucleoprotein granules and, in astrocytes, fusion of rosette ribosomes and enlargement of mitochondria. A decrease in luminal area occurs in capillaries 40 min after trauma applied alone. Hypoxia without trauma leads to a significant increase in capillary luminal area, which, however, is abolished when trauma precedes the hypoxic interlude. Intravenous injection of a non-diuretic, fluorenyl derivative (L-644,711) of (aryloxy)alkanoic acid loop diuretics, completely prevents the astrocytic swelling ordinarily present 40 min after acceleration-deceleration injury. Also, L-644,711 improves mortality and morbidity scores in cats subjected to trauma with hypoxia. We suggest that astroglial swelling may be a critical step in the evolving pathology of this head injury model and its prevention, as by L-644,711 administration, may have relevance to the treatment of cerebral edema in human head injury and other clinical disorders accompanied by astrocytic swelling.

Animals↗
PubMed1987

[Traumatic ruptures of the thoracic aorta].

1) Traumatic rupture of the thoracic aorta is most frequently caused by a traffic accident with deceleration. Approximately 80% of these patients die immediately. In 29 patients (1973-1986) reaching surgical treatment, all aortic lesions were located at the aortic isthmus (28 covered and 1 free rupture). 25 (86%) of them had serious associated injuries of the head, other thoracic or intraabdominal organs and/or the extremities. A seat belt could not prevent the deceleration injury of the aorta but reduced associated injuries of the head and the intraabdominal organs. 2) The widely accepted surgical rule that every diagnosed traumatic aortic rupture should have an immediate surgical repair is no longer acceptable. In all patients with a clinically and angiographically stable covered rupture of the aorta with serious associated injuries and symptoms of shock the surgical treatment of the aortic lesion should be undertaken with delayed emergency after some hours or several days. This changed surgical concept is based both on the rarity of secondary free rupture of the aortic lesion and on the chance to stabilize the circulatory condition by a primary shock treatment including the surgical elimination of other sources of blood loss. The group with such a delayed aortic vascular repair (n = 12) showed a remarkably improved outcome with reduced operative mortality and reduced risk of paraplegia (47% vs. 25% respectively 35% vs. ca. 10%). None of these patients with a delay up to 17 days for vascular repair developed a secondary free aortic rupture. Up to recently this risk has been obviously overestimated on the basis of earlier studies in the sixties. 3) The immediate repair of the aortic rupture with its high operative mortality and high rate of ischemic paraplegia can be restricted to a few exceptional cases with a secondary free rupture in the hospital. The transvenous DSA is the best approach for an early diagnosis and for the surgical decision to perform vascular repair immediately or with delay.

Accidents, Traffic↗
PubMed1978

Female self-report and autonomic responses to sexually pleasurable and sexually aversive readings.

This study was designed to investigate possible differential autonomic responses to sexually pleasurable and sexually aversive readings. Reading conditions were counterbalanced so that an equal number of subjects received both orders of the two readings. Female subjects' ratings, skin conductance (SC), finger pulse (FP), and heart rate (HR), in response to these readings were compared. The sexually pleasurable as compared to the sexually aversive passage was rated as more sexually stimulating, less anxiety and guilt provoking, and less disgusting, but as equally well portrayed and interesting (extent of boredom). While essentially equal SC increases were noted in response to both readings, HR deceleration and vasodilation were more characteristic of the response to the sexually pleasurable passage. These findings were compared within the context of preexperimental setting conditions and were interpreted in terms of Lacey's intake-rejection hypothesis. These findings are consistent with the idea that pleasurable sexual readings are associated with interest, attention, and heart rate deceleration, whereas aversive material may be related to rejection of the material and to heart rate acceleration.

Arousal↗