Brain signatures of meaning access in action word recognition

The brain basis of action words may be neuron ensembles binding language- and action-related information that are dispersed over both language- and action-related cortical areas. This predicts fast spreading of neuronal activity from language areas to specific sensorimotor areas when action words semantically related to different parts of the body are being perceived. To test this, fast neurophysiological imaging was applied to reveal spatiotemporal activity patterns elicited by words with different action-related meaning. Spoken words referring to actions involving the face or leg were presented while subjects engaged in a distraction task and their brain activity was recorded using high-density magnetoencephalography. Shortly after the words could be recognized as unique lexical items, objective source localization using minimum norm current estimates revealed activation in superior temporal (130 msec) and inferior frontocentral areas (142-146 msec). Face-word stimuli activated inferior frontocentral areas more strongly than leg words, whereas the reverse was found at superior central sites (170 msec), thus reflecting the cortical somatotopy of motor actions signified by the words. Significant correlations were found between local source strengths in the frontocentral cortex calculated for all participants and their semantic ratings of the stimulus words, thus further establishing a close relationship between word meaning access and neurophysiology. These results show that meaning access in action word recognition is an early automatic process ref lected by spatiotemporal signatures of word-evoked activity. Word-related distributed neuronal assemblies with specific cortical topographies can explain the observed spatiotemporal dynamics reflecting word meaning access.     

Plasma 8-isoprostane is increased in preterm infants who develop bronchopulmonary dysplasia or periventricular leukomalacia

Our aim was to assess the plasma free 8-epi-prostaglandin F(2alpha) (8-isoprostane) and ascorbyl radical as risk indicators for oxidative damage in extremely low birth weight infants (ELBWIs) and the effect of N-acetylcysteine (NAC) on these markers. Plasma samples were collected on days 3 and 7 of life from infants who were enrolled in a randomized, controlled trial in which i.v. NAC or placebo was administered to ELBWIs during the first week of life, with the aim of preventing bronchopulmonary dysplasia (BPD). Plasma 8-isoprostane was analyzed in 83 infants using an enzyme immunoassay kit. Ascorbyl radical concentration was measured in 61 infants with electron spin resonance spectroscopy. The 8-isoprostane concentrations were similar in the NAC and placebo groups. In infants who later developed BPD or died (n = 29), the median (range) 8-isoprostane concentration was significantly higher (p = 0.001) on day 3 and day 7 [50.0 pg/mL (19-360) and 57.0 pg/mL (14-460), respectively] than in survivors without BPD [n = 54; 34.5 pg/mL (5-240) and 39.5 pg/mL (7-400), respectively]. The 8-isoprostane levels increased significantly more (p < 0.05) in infants who later developed periventricular leukomalacia. NAC treatment or the later development of BPD was not related to the ascorbyl radical levels. The ascorbyl radical level decreased significantly in all groups from day 3 to day 7, but the difference between the groups was not significant. The mean (SD) ascorbyl radical level on day 3 was significantly higher (p < 0.01) in infants who later developed periventricular leukomalacia [287 (124) versus 194 (90)]. These data suggest that plasma 8-isoprostane could serve as a marker in assessing the risk for BPD development in ELBWIs.     

Pharmacodynamics and pharmacokinetics of high-dose oxycodone infusion during and after coronary artery bypass grafting

OBJECTIVE: In small to moderate doses, oxycodone has similar analgesic efficacy to morphine with fewer side effects. The present study evaluated the pharmacokinetics and dynamics of high doses of oxycodone during anesthesia for primary coronary artery bypass grafting. DESIGN: A randomized, prospective clinical evaluation. SETTING: A major Scandinavian university clinic. PARTICIPANTS: Two groups with 10 patients each were studied. INTERVENTIONS: Invasive hemodynamics, echocardiograms, and electrocardiograms were monitored. Oxycodone kinetics, histamine liberation, and plasma cortisol levels were measured. Anesthesia was induced with 1.0 mg/kg of oxycodone and, thereafter, in a random order, maintained with a continuous infusion of oxycodone at a rate of either 0.5 mg/kg/h (group OX 0.5, 10 patients) or 1.0 mg/kg/h (group OX 1.0, 10 patients). An additional bolus dose of 0.5 mg/kg (OX 0.5) or 1.0 mg/kg (OX 1.0) of oxycodone was given before the incision. Enflurane was administered according to hemodynamic criteria. MEASUREMENTS AND MAIN RESULTS: The induction of and the course of anesthesia were hemodynamically stable in all patients. Enflurane was given to every patient. The mean total doses of oxycodone were 3.5 mg/kg (OX 0.5) and 6.2 mg/kg (OX 1.0). The median t(1/2) of oxycodone varied from 5.1 to 5.9 hours. No hemodynamic differences were found between the groups. No histamine liberation was detected. During anesthesia, the predominant waves in the EEG were theta;- and delta-waves. The mean times to awakening were 3.8 hours and 7.0 hours in the groups OX 0.5 and 1.0, respectively. All patients were intubated until the first postoperative morning. No recall of awareness was reported. CONCLUSION: A combination of oxycodone and enflurane provides hemodynamically stable anesthesia. No advantages were gained with the higher dose. Elimination of oxycodone was slower than reported previously.     

Pulmonary artery blood temperature at admission to the intensive care unit is predictive of outcome after on-pump coronary artery bypass surgery

OBJECTIVE: To evaluate whether pulmonary artery blood (PA) temperature on admission to the intensive care unit (ICU) is predictive of postoperative outcome after isolated on-pump coronary artery bypass grafting (CABG). DESIGN: A retrospective study on 1639 patients who underwent isolated on-pump CABG in whom PA temperature at admission to the ICU was available for review. RESULTS: Thirty-three patients (2.0%) died during the in-hospital stay and 87 patients (5.3%) developed low cardiac output syndrome. PA temperature at admission to the ICU was significantly associated with an increased risk of overall postoperative death (p = 0.002), cardiac death (p = 0.03), and low cardiac output syndrome (p < 0.0001), and was significantly correlated with prolonged length of ICU stay (p < 0.0001) and postoperative bleeding (p = 0.001). Patients with high PA temperature had significantly more severe comorbidities, and longer aortic cross-clamping and cardiopulmonary bypass time. The receiver operating characteristic curve showed that PA temperature at admission to the ICU in predicting postoperative death had an area under the curve of 0.660 (p = 0.002) and its best cut-off value was 36.4 degrees C (sensitivity: 63.6%, specificity: 65.2%). When the PA temperature at admission to the ICU was > or = 36.4 degrees C, the postoperative mortality and low cardiac output syndrome rates were 3.6 and 8.3%, whereas they were 1.1 and 3.7% when the PA temperature at admission to the ICU was < 36.4 degrees C (p = 0.001, p < 0.0001), respectively. CONCLUSION: Patients having a PA temperature > or =36.4 degrees C at admission to the ICU after CABG seem to be at higher risk of poor postoperative outcome.     

Automatic time perception in the human brain for intervals ranging from milliseconds to seconds

Time perception in everyday life deals with various intervals. Here we investigated whether an automatic duration-discrimination mechanism in audition operates even for intervals of an order of seconds, by using the mismatch negativity (MMN), an index of automatic change detection in audition. In Experiment 1, occasional decrements of the duration of a repetitive "standard" tone elicited an MMN in subjects ignoring auditory stimulation, even with the standard-stimulus durations over a second. Nevertheless, the MMN amplitude was significantly diminished with standard-stimulus durations of 800 ms and above, despite the fact that a constant deviant versus standard duration ratio was used. Complementary experiments varying the interstimulus interval (Experiment 2) and the magnitude of duration change (Experiment 3) yielded corroborating results. The present results suggest that automatic duration discrimination in audition operates even for durations of the order of seconds; yet its optimum time scale might be of the order of milliseconds.     

Long-term outcome after intravenous thrombolysis of basilar artery occlusion

Context  Basilar artery occlusion (BAO) is an infrequent disease with high morbidity and mortality. Intra-arterial thrombolysis is advocated for treatment but is limited to use at specialized centers. Objective  To evaluate outcomes for patients with BAO treated with intravenous thrombolytic therapy. Design, Setting, and Participants  During 1995 to 2003, 50 consecutive patients with angiographically proven BAO were treated according to an institutional therapy protocol based on intravenous thrombolysis with recombinant tissue plasminogen activator (alteplase). Patients were treated at an urban university teaching hospital receiving all patients with ischemic stroke who were considered for thrombolysis in a catchment area of 1.5 million inhabitants in Helsinki, Finland. Intervention  Intravenous administration of alteplase (0.9 mg/kg) during a 1-hour infusion. Main Outcome Measures  Basilar artery recanalization determined by magnetic resonance angiography and clinical outcomes at 3 months and at 1 year or longer determined by modified Rankin Scale and Barthel Index scores. Results  Recanalization was studied in 43 patients and verified in 26 (52%) of all patients. By 3 months, 20 patients (40%) had died while 11 had good outcomes (modified Rankin Scale score, 0-2); 12 (24%) reached independence in activities of daily living (Barthel Index score, 95-100), and 6 (16%) were severely disabled (Barthel Index score, 0-50). In the long term (median follow-up 2.8 years), 15 patients (30%) reached good outcomes (modified Rankin Scale score, 0-2) while 23 (46%) died. Conclusions  Intravenous administration of alteplase for patients with BAO appears to be associated with rates of survival, recanalization, and independent functional outcome comparable with those reported with endovascular approaches. These data suggest that a randomized trial is needed to compare these approaches for treatment of BAO.      

Published evidence on the success of telecardiology: a mixed record

We carried out a systematic review of the literature on telecardiology assessment from 1992 to September 2003. We selected articles reporting clinical, economic or administrative outcomes. Quality of evidence was assessed using an approach that considered both study design and study performance. Forty-four studies met the selection criteria. Studies of home care applications, particularly management of congestive heart failure, were of highest quality, giving a high degree of confidence in their findings. Studies on paediatric and non-emergency adult hospital applications were of poorer quality; they were mostly reports of case series and gave relatively little detail. Economic analysis was limited to cost studies and in most cases was judged to be of poor to fair quality. While telecardiology has been widely applied, there is still limited good-quality evidence of its benefits to health-care. Success in establishing the feasibility of telecardiology applications is offset by a failure to obtain convincing data on their influence on health outcomes and on their cost-effectiveness.     

Do younger female breast cancer patients have a poorer prognosis? Results from a population‐based survival analysis

Younger women who develop breast cancer are hypothesized to have poorer survival rates than women who develop it at a later stage in life. Several studies have suggested that differences in biologic characteristics of breast cancer in younger (premenopausal) and older (postmenopausal) women may account for the prognostic variation. This population-based cohort study reports on survival rates of breast cancer in Singapore and examines the hypothesis that younger breast cancer patients have a poorer prognosis. A total of 6,397 breast cancer patients diagnosed from 1968 to 1992 were identified from the population-based cancer registry and followed up through 1997. Outcome measures were relative survival rates (RSRs) calculated using Hakulinen's method and excess hazards ratios (HRs) derived from a regression model based on relative survival. The 2-, 5- and 10-year RSRs were worse among those aged > 75 (65%, 48% and 39%, respectively). The best survival rates were seen among those aged 40-44 (84%, 67% and 56%). Patients younger than 35 years faired reasonably well (79%, 60% and 50%). When the data were stratified according to clinical stage and calendar year, the highest risk of excess deaths was found in women > or = 75 years old. In patients with localized cancer and/or regional metastases, those in the 35-39 age group had the lowest excess risk. In patients with distant metastases, those younger than 35 years of age had the lowest excess risk of death. At the population level, younger women (< 45 years) with breast cancer in Singapore have higher relative survival rates.     

Activation in the anterior left auditory cortex associated with phonological analysis of speech input: localization of the phonological mismatch negativity response with MEG

The spatio-temporal dynamics of cortical activation underlying auditory word recognition, particularly its phonological stage, was studied with whole-head magnetoencephalography (MEG). Subjects performed a visuo-auditory priming task known to evoke the phonological mismatch negativity (PMN) response that is elicited by violations of phonological expectancies. Words and non-words were presented in separate conditions. In each of the 318 trials, the subjects first saw a word/non-word (e.g., 'cat') that was soon followed by a prime letter (e.g., 'h'). Their task was to replace mentally the sound of the first letter of the word/non-word with the prime letter, thus resulting in a new word/non-word (e.g., 'hat'). Finally, an auditory word/non-word either matching or mismatching with the anticipated item was presented. In most subjects, a PMNm followed by a later, N400m-like negativity was obtained in the left hemisphere to the mismatching auditory stimuli. A similar response pattern was obtained in the right hemisphere only in a few subjects. Source localization of the N1m, an index of acoustic analysis, and the PMNm and N400m-like responses was performed using L1 minimum-norm estimation. In the left hemisphere, the PMNm source for the words was significantly more anterior than the source of the N400m-like response; for the non-words, the PMNm source was significantly more anterior than the sources of the N1m and the N400m-like response. These results suggest that the left-hemisphere neuronal networks involved in sub-lexical phonological analysis are at least partly different from those responsible for the earlier (acoustic) and later (whole item) processing of speech input.