Differences in bone mineral density between the right and left hips in postmenopausal women

Bone mineral density (BMD) using dual energy radiography absorptiometry are commonly used for the diagnosis of osteoporosis. It is usually measured at the spine and also at one hip joint. Controversy still exists regarding the use of bilateral hip scanning. We analyzed the difference of BMD at bilateral hips in 384 postmenopausal women, retrospectively. The concordance and discordance rates of the lowest T-score and BMD between both hips were evaluated. The BMDs of the femoral neck and trochanter were significantly different between both hips (P < 0.05). There were also discrepancies between the lowest T-scores of both hips (P < 0.05). The discordance rates were about 30%. Due to significant differences in BMD between both hips at the femoral neck and trochanter and high discordance rate, bilateral hip measurements using DEXA are recommended to avoid underestimating osteoporosis.     

Functional compensation of the left inferior longitudinal fasciculus for picture naming

ABSTRACT

The role of the left inferior longitudinal fasciculus (ILF) in language processing has been called into question by recent studies showing that disruption of this tract in glioma patients did not necessarily lead to detrimental effects on spoken language, especially on picture naming. Here we show that disruption of the left ILF with axonal stimulation in patients undergoing an “awake” surgery for a slow-growing tumour systematically induces pure anomia, but only when the temporal pole (TP) is not infiltrated by the tumour. This finding not only confirms that the ILF plays a role in lexical retrieval in normal circumstances but also suggests that the information conveyed by this tract can be rerouted to alternative pathways when the TP is widely lesioned and abandons its function. This conclusion is further supported by the case of a patient who developed a long-lasting anomic aphasia after a surgically preplanned interruption of the ILF.     

Effects of lesions to the left lateral prefrontal cortex on task-specific top-down biases and response strategies in blocked-cyclic naming

Anders, Riès, van Maanen and Alario put forward evidence accumulation modelling of object naming times as an alternative to neural network models of lexical retrieval. The authors exemplify their approach using data from the blocked-cyclic naming paradigm, requiring speakers to repeatedly name small sets of related or unrelated objects. The effects observed with this paradigm are understood reasonably well within the tradition of neural network modelling. However, implemented neural network models do not specify interfaces for task-specific top-down influences and response strategies that are likely to play a role in the blocked-cyclic naming paradigm, distinguishing it from continuous, non-cyclic manipulations of the naming context. I argue that the evidence accumulation approach falls short on this account as well, as it does not specify the potential contribution of task-specific top-down processes and strategic facilitation effects to the response time distributions. Future endeavours to model or fit data from blocked-cyclic naming experiments should strive to do so by simultaneously considering data from continuous context manipulations.     

Proprioceptive localization of the left and right hands

The present study examined the accuracy of proprioceptive localization of the hand using two paradigms. In our proprioceptive estimation paradigm, participants judged the position of a target hand relative to visual references, or their body’s midline. Placement of the target hand was active (participants pushed a robot manipulandum along a constrained path) or passive (the robot manipulandum positioned participants’ target hand). In our proprioceptive-guided reaching paradigm, participants reached to the unseen location of a hand; both the left and right hands served as the target hand and the reaching hand. In both paradigms, subjects were relatively good at estimating the location of each hand (i.e. relative to a reference marker or using a reach), with directional errors falling within 2 cm of the actual target location, and little variation across the workspace. In our proprioceptive estimation paradigm, biases when the target hand was passively placed were no larger than those made when the target hand was actively placed. Participants perceived their left hand to be more to the left than it actually was, and their right hand to be more rightward than it actually was, but with a similar error magnitude across target hands. In our reaching paradigm, participants’ estimates of left hand location were deviated more leftwards than their estimates of right hand location, but showed a small but similar pattern of location-dependent reach errors across the two hands. Precision of estimates did not differ between the two hands or vary with target location for either paradigm.     

Cardiac function in open-chest dogs after left to right ventricular shunting and right coronary artery occlusion

Patients with acquired ventricular septal defect (VSD) after myocardial infarction have a particularly bad prognosis if right ventricular function is severely impaired. The significance of an ischaemic right ventricular free wall on cardiac function during interventricular shunting was examined in open-chest dogs. An external interventricular shunt could be opened and closed at will, and by occlusion of the right coronary artery (RCA), a part of the right ventricular free wall was rendered ischaemic. Aortic flow decreased by 8 +/- 2% when the shunt was opened in the presence of a normal right ventricle, and by 16 +/- 2% (difference: P less than 0.05) in the presence of right ventricular ischaemia. Aortic flow fell by 19 +/- 3% when the RCA was occluded. Right ventricular dyskinesia was demonstrated after occlusion of RCA, by recording segment lengths in the right ventricular free wall. The dyskinesia was aggravated when the shunt was opened. The left ventricle exerted a 'negative' work on the ischaemic right ventricular free wall. Retention of blood in the right ventricle, with a subsequent decline in left ventricular filling and an almost unchanged interventricular shunting of blood, explain why aortic flow fell more when the shunt was opened in the presence of right ventricular ischaemia.     

Response of cardiomyocytes of the right heart to trauma of the left

A myocardial infarct in the left ventricle was produced in adult rats weighing 120–160 g by ligation of the left coronary artery; the left atrium was injured; or a mock operation was performed and the pericardium was removed. On the fifth day after the operation dividing myocytes were found in the right atrium (mitotic index 0.7–8.8) and in the subepicardial zone of the right ventricle (mitotic index 0.8–2.9). In old rats weighing 300–430 g, on the third day after the various types of injury to the myocardium, mitotic activity was found in the myocytes of the left auricle (1–5.1), and in one of eight cases in the right auricle (4.2); single mitoses also were found in the subepicardial zone of the left ventricle.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 5, pp. 610–612, May, 1977.     

Pressure-flow characteristics in the right and left ventricular perfusion territories of the right coronary artery in swine

Regional pressure-flow relationships within the right coronary artery (RCA) circulation of swine were determined. Enflurane-anaesthetized swine (n=7) were studied during step-wise reductions of RCA perfusion pressure using an extracorporeal circuit. Regional blood flow was measured using microspheres and contractile function of the right ventricle was measured using sonomicrometry. The RCA perfusion territory was divided into its anatomic components: right ventricular free wall (RV), interventricular septum (with further division in transmural thirds; SEP-LV, SEP-MID and SEP-RV) and right atrium (RA). Pressure-flow relations were constructed for each region and autoregulatory capacity assessed through calculation of an autoregulatory index (AI, closed-loop gain). The pressure-flow relationship for the entire RCA exhibited autoregulation down to a pressure of 40 mmHg. The SEP-LV exhibited a similar relationship with loss of autoregulation at approximately 40 mmHg. The pressure-flow relationship of the RV, however, showed autoregulation to a pressure of 30 mmHg with a decrease of blood flow only at a pressure of 20 mmHg. Little autoregulation was observed in the RA. Autoregulatory gain assessed by AI was similar in RV, SEP-LV and SEP-RV as pressure was reduced from 90 to 55 mmHg (RV=0.54±0.41; SEP-LV=0.58±0.36; SEP-RV=0.83±0.36). With further reductions of pressure, AI was highest in the RV, followed by the SEP-RV and then SEP-LV. AI of the SEP-LV and SEP-RV was negative when pressure was reduced from 30 to 20 mmHg. AI of the RA was negative at the high and low pressure ranges and demonstrated little autoregulatory gain otherwise. Regional contractile function of the RV was maintained to a pressure of 30 mmHg and appeared to be closely related to regional blood flow. Thus, the RCA perfusion bed is characterized by a markedly heterogeneous autoregulatory capacity based on its anatomical makeup.     

Effects of right and left vagal stimulation on left ventricular acetylcholine levels in the cat

To test the effectiveness of, and the interactions between, right and left vagal stimulation on left ventricular acetylcholine (ACh) levels, we applied the dialysis technique to the heart of anaesthetized cats. Dialysis probes were implanted in the left ventricular myocardium and perfused with Krebs–Henseleit buffer containing eserine. Dialysate ACh content was measured as an index of ACh release from post‐ganglionic vagal nerve terminals in the left ventricular myocardium. We electrically stimulated the right and left cervical vagal nerves separately or together and investigated the dialysate ACh response. In two different regions of the left ventricle, substantial dialysate ACh responses were observed by the stimulation (20 Hz) of both right and left cervical vagal nerves. At stimulation frequencies of both 10 and 20 Hz, the dialysate ACh response to the bilateral vagal stimulation was almost algebraically the calculated sum of the individual dialysate ACh responses to unilateral vagal stimulation. In conclusion, ACh levels in the left ventricle are affected by both right and left vagal nerves and show little evidence of interactions between right and left vagal nerves at the level of the cardiac ganglia.     

Concurrent adaptations of left and right arms to opposite visual distortions

Previous research has shown that subjects can adapt with either arm to an opposite visual distortion, and the two adaptive states can then be used in sequence to control the respective arm. To extend this finding, we exposed the left and right arms of our subjects to opposite-directed rotations of the visual field alternately for 20 s each, and determined the time-course of adaptation, as well as aftereffects without visual feedback under uni- and bimanual conditions. Our data confirm that two adaptive states can co-exist in the sensorimotor system, one for each arm. We further found that the time-course of adaptive improvement was similar for both arms, that the improvement was present as early as the first movement after a change of arm and discordance, and that the magnitude of adaptation was similar to control data yielded by a single arm and discordance. Taken together, these findings suggest that the two adaptive states were formed concurrently, and without mutual interference. We also observed significant aftereffects. They were smaller but still appreciable under bimanual conditions; the two arms moved at the same time in different directions even though they were aimed at a common visual target. This outcome indicates that the two adaptive states were not merely of a strategic nature, but rather changed the rules by which sensory information was transformed into motor outputs; it also suggests that the two states not only co-exist, but can also be engaged concurrently in movement control. The reduced aftereffects observed under bimanual conditions can be attributed to the well-known phenomenon of bimanual coupling, which is unrelated to adaptation.     

Morphometry of nasal bases and nostrils in Koreans.

To investigate morphological characteristics of Korean noses, nasal bases and nostrils were measured and classified in Korean adults. The height and the width of the nasal base, the height and the width of the columella, the length of the long and short nostril axes, and nasal alar angle were measured. The shapes of the nostrils were classified into 7 types by the angle between the right and left long axes of the nostrils. Each measurement was compared with other studies.     

Visual object naming in patients with small lesions centered at the left temporopolar region

Naming is considered a left hemisphere function that operates according to a posterior–anterior specificity gradient, with more fine-grained information processed in most anterior regions of the temporal lobe (ATL), including the temporal pole (TP). Word finding difficulties are typically assessed using visual confrontation naming tasks, and have been associated with selective damage to ATL resulting from different aetiologies. Nonetheless, the role of the ATL and, more specifically, of the TP in the naming network is not completely established. Most of the accumulated evidence is based on studies on patients with extensive lesions, often bilateral. Furthermore, there is a considerable variability in the anatomical definition of ATL. To better understand the specific involvement of the left TP in visual object naming, we assessed a group of patients with an epileptogenic lesion centered at the TP, and compared their performance with that of a strictly matched control group. We also administered a battery of verbal and non-verbal semantic tasks that was used as a semantic memory baseline. Patients showed an impaired naming ability, manifesting in a certain degree of anomia and semantically related naming errors, which was influenced by concept familiarity. This pattern took place in a context of mild semantic dysfunction that was evident in different types and modalities of semantic tasks. Therefore, current findings demonstrate that a restricted lesion to the left TP can cause a significant deficit in object naming. Of importance, the observed semantic impairment was far from the devastating degradation observed in semantic dementia and other bilateral conditions.     

Effects of right and left vagal stimulation on left ventricular acetylcholine levels in the cat.

To test the effectiveness of, and the interactions between, right and left vagal stimulation on left ventricular acetylcholine (ACh) levels, we applied the dialysis technique to the heart of anaesthetized cats. Dialysis probes were implanted in the left ventricular myocardium and perfused with Krebs-Henseleit buffer containing eserine. Dialysate ACh content was measured as an index of ACh release from post-ganglionic vagal nerve terminals in the left ventricular myocardium. We electrically stimulated the right and left cervical vagal nerves separately or together and investigated the dialysate ACh response. In two different regions of the left ventricle, substantial dialysate ACh responses were observed by the stimulation (20 Hz) of both right and left cervical vagal nerves. At stimulation frequencies of both 10 and 20 Hz, the dialysate ACh response to the bilateral vagal stimulation was almost algebraically the calculated sum of the individual dialysate ACh responses to unilateral vagal stimulation. In conclusion, ACh levels in the left ventricle are affected by both right and left vagal nerves and show little evidence of interactions between right and left vagal nerves at the level of the cardiac ganglia.     

Differences in the accuracy of human visuospatial memory after yaw and roll rotations

Our ability to keep track of objects in the environment, even as we move, has been attributed to various cues including efference copies, vestibular signals, proprioception, and gravitational cues. However, the presence of some cues, such as gravity, may not be used to the same extent by different axes of motion (e.g., yaw vs. roll). We tested whether changes in gravitational cues can be used to improve visuospatial updating performance for yaw rotations as previously shown for roll. We found differences in updating for yaw and roll rotations in that yaw updating is not only associated with larger systematic errors but is also not facilitated by gravity in the same way as roll updating.