Comparison of the Semmes-Weinstein monofilaments with the Pressure-Specifying Sensory Device

Measuring human sensibility remains a challenge, with the primary limitation being the instrumentation traditionally available. The Pressure-Specifying Sensory Device (PSD) permits quantitation of the human pressure perception threshold by means of transducers that couple two rounded prongs to a personal computer. If just one prong is perceived in constant contact with the skin, the cutaneous pressure threshold is directly obtained, scaling along a continuum from .05 to 100 g/mm2 (readout on computer monitor). This measurement is analogous to that obtained with the series of Semmes-Weinstein monofilaments (SWM) (readout in logarithmic marking on nylon rod). The present study evaluated twenty normal volunteers and ten nerve-impaired patients with both the PSD and the SWM. There was a poor correlation between the measurement offeree (r = 0.21) and pressure (r = 0.29) obtained with the PSD and the SWM. This study reaffirms the value of measuring pressure perception threshold during the sensibility evaluation, while calling attention to selection of instrumentation for obtaining this measurement.     

What is normal binocular vision?

The vergence position of the eyes is determined by the near fixation-accommodationmiosis synkinesis and the fusion mechanism. The contribution of both systems was analysed in 30 normal subjects and 16 subjects with abnormal binocular vision. Prism fixation disparity curves were determined in three different experimental situations: the routine method according to Ogle, a method to stimulate the synkinetic convergence (Experiment I, with one fixation point as sole binocular stimulus) and a method to stimulate the fusion mechanism (Experiment II, with random dot stereograms). Experiment I produced flat curves and Experiment II steep curves. The mean diameter of the horizontal Panum area was 5 minutes of arc in Experiment I and 2 in Experiment II. On the basis of these findings, it was postulated that the synkinetic system operates in the absence of fixation disparity and the fusion system in the presence of fixation disparity. In Experiment II, esodisparities of 100 minutes of arc occur in a number of normal subjects.The dividing line between normal and abnormal binocular vision therefore is blurred. Normal persons can display disparities, the order of magnitude of which is equal to that of the angle of squint in micro-strabismus.     

Ambulatory labor epidural analgesia: bupivacaine versus ropivacaine

Dilute concentrations of bupivacaine combined with fentanyl have recently been used to initiate labor epidural analgesia in an attempt to balance adequate analgesia and minimal maternal motor blockade. Similar concentrations of ropivacaine have not been evaluated. This prospective, randomized, double-blinded study was designed to compare the efficacy of 20 mL of either 0.08% bupivacaine plus 2 microg/mL fentanyl or 0.08% ropivacaine plus 2 microg/mL fentanyl to initiate ambulatory labor epidural analgesia. Forty nulliparous women in early ( 0 but < 20 at 20 min. The time (mean +/- SD) to visual analog scale score = 0 was BF (n = 18): 12.0 +/- 4.5 min and RF (n = 19): 12.4 +/- 4.0 min (P > 0.05). Spontaneous micturition was observed in 65% (13 of 20) BF compared with 100% (20 of 20) RF (P < 0.01), and ambulation was demonstrated in 75% (15 of 20) BF compared with 100% (20 of 20) RF (P < 0.03). The incidence of forceps delivery was 35% (7 of 20) BF compared with 10% (2 of 20) RF (P < 0.04). The results of this study indicate that dilute ropivacaine combined with fentanyl effectively initiates epidural analgesia while concurrently preserving maternal ability to void and ambulate. Implications: As compared with a similar dilute concentration of bupivacaine, 20 mL of dilute (0.08%) ropivacaine combined with fentanyl (2 microg/mL) effectively initiates epidural analgesia in nulliparous women in early, established labor while preserving their ability to micturate and ambulate. Of importance, it appears that a true ambulatory epidural analgesic for women in labor is now possible.     

Reduced reciprocal inhibition is seen only in spastic limbs in patients with neurolathyrism

If reduced reciprocal inhibition plays a causal role in the pathophysiology of spasticity as has been suggested in several studies, the inhibition is expected to be impaired in spastic, but not in normal muscles. Patients with neurolathyrism offer a possibility of testing this prediction since the spastic symptoms in these patients are restricted to the lower extremities only. Three patients with neurolathyrism were tested. Their data were compared with 15 age-matched healthy subjects. All patients showed signs of spasticity in the legs. Two patients had normal voluntary muscle force in the lower extremities and one had decreased force. No clinical abnormalities were found in the upper extremities. Reciprocal inhibition between ankle dorsiflexor and plantarflexor muscles was absent in all patients, whereas the inhibition between wrist extensor and flexor muscles was present and of normal size and latency. These findings are consistent with the hypothesis that reduced reciprocal inhibition plays a causal role in the pathophysiology of spasticity.     

Chronic intravascular hemolysis after aortic valve replacement with Ionescu-Shiley xenograft: Comparative study with Bjork-Shiley prosthesis

Twenty patients with a prosthetic valve (Ionescu-Shiley or Bjork-Shiley) in the aortic position were studied for evidence of intravascular hemolysis. Serum lactic dehydrogenase and serum haptoglobin levels were used as the most sensitive indicators of hemolysis. Elevated concentrations of lactic dehydrogenase were found in all 10 patients with an Ionescu-Shiley prosthesis (mean 402 IU/liter) and in 7 of 10 patients with a Bjork-Shiley prosthesis (mean 234 IU/liter). The mean serum haptoglobin was 15 mg/dl (range 10 to 28) in patients with the Ionescu-Shiley valve and 96 mg/dl (15 to 284) for those with the Bjork-Shiley valve. This study indicates the presence of chronic intravascular hemolysis in patients with the Ionescu-Shiley aortic valve. The increase in lactic dehydrogenase was significantly greater in patients with the Ionescu-Shiley prosthesis than in those with the Bjork-Shiley prosthesis, indicating a slightly shorter red cell life span in the former group.     

Reward-related neural responses are dependent on the beneficiary

Prior studies have suggested that positive social interactions are experienced as rewarding. Yet, it is not well understood how social relationships influence neural responses to other persons’ gains. In this study, we investigated neural responses during a gambling task in which healthy participants (N = 31; 18 females) could win or lose money for themselves, their best friend or a disliked other (antagonist). At the moment of receiving outcome, person-related activity was observed in the dorsal medial prefrontal cortex (dmPFC), precuneus and temporal parietal junction (TPJ), showing higher activity for friends and antagonists than for self, and this activity was independent of outcome. The only region showing an interaction between the person-participants played for and outcome was the ventral striatum. Specifically, the striatum was more active following gains than losses for self and friends, whereas for the antagonist this pattern was reversed. Together, these results show that, in a context with social and reward information, social aspects are processed in brain regions associated with social cognition (mPFC, TPJ), and reward aspects are processed in primary reward areas (striatum). Furthermore, there is an interaction of social and reward information in the striatum, such that reward-related activity was dependent on social relationship.     

Top‐down and bottom‐up influences on the left ventral occipito‐temporal cortex during visual word recognition: An analysis of effective connectivity

The functional role of the left ventral occipito‐temporal cortex (vOT) in visual word processing has been studied extensively. A prominent observation is higher activation for unfamiliar but pronounceable letter strings compared to regular words in this region. Some functional accounts have interpreted this finding as driven by top‐down influences (e.g., Dehaene and Cohen [ 2011 ]: Trends Cogn Sci 15:254–262; Price and Devlin [ 2011 ]: Trends Cogn Sci 15:246–253), while others have suggested a difference in bottom‐up processing (e.g., Glezer et al. [ 2009 ]: Neuron 62:199–204; Kronbichler et al. [ 2007 ]: J Cogn Neurosci 19:1584–1594). We used dynamic causal modeling for fMRI data to test bottom‐up and top‐down influences on the left vOT during visual processing of regular words and unfamiliar letter strings. Regular words (e.g., taxi) and unfamiliar letter strings of pseudohomophones (e.g., taksi) were presented in the context of a phonological lexical decision task (i.e., “Does the item sound like a word?”). We found no differences in top‐down signaling, but a strong increase in bottom‐up signaling from the occipital cortex to the left vOT for pseudohomophones compared to words. This finding can be linked to functional accounts which assume that the left vOT contains neurons tuned to complex orthographic features such as morphemes or words [e.g., Dehaene and Cohen [ 2011 ]: Trends Cogn Sci 15:254‐262; Kronbichler et al. [ 2007 ]: J Cogn Neurosci 19:1584–1594]: For words, bottom‐up signals converge onto a matching orthographic representation in the left vOT. For pseudohomophones, the propagated signals do not converge, but (partially) activate multiple orthographic word representations, reflected in increased effective connectivity. Hum Brain Mapp 35:1668–1680, 2014. © 2013 Wiley Periodicals, Inc.