A systematic review of interventions and outcomes in lung cancer metastases to the spine.

Seventy percent of cancer patients will have metastatic bone disease, most commonly in the vertebra. Prognosis of metastatic lung cancer is poor and treatment is mostly palliative. To-date, there is no systematic review on the ideal treatment for lung cancer with spinal metastases in regards to mortality. Literature searches were performed based on PRISMA guidelines for systematic review. Thirty-nine studies comprising 1925 patients treated for spinal metastases of lung cancer met inclusion criteria. All analyses were performed using SAS and SPSS. Data were analyzed for meaningful comparisons of baseline patient characteristics, primary cancer type, metastatic lesion characteristics, treatment modality, and clinical and radiologic outcomes. Significantly greater mean survival length was seen in the non-surgical group (8.5 months, SD 6.6, SEM 0.17) compared to the surgical group (7.5 months, SD 4.5, SEM 0.25; p = 0.013). There was no statistically significant survival difference between different types of primary lung cancer: NSCLC (8.3 months, SD 13.8, SEM 0.91) and SCLC (7.0 months, SD 4.6, SEM 0.46; p = 0.36). Number of vertebral levels involved per lesion also did not exhibit significant difference: single lesion (11.3 months, SD 6.8, SEM 2.2) and multiple lesions (13.8 months, SD 15.7, SEM 3.6; p = 0.64). For patients with symptomatic spinal metastases from lung cancer, non-operative approaches experience significantly better survival outcomes (p = 0.013). Future clinical studies are needed to determine the best treatment algorithm to help maximize outcomes and minimize mortality in metastatic lung cancer.

Oxygen saturation or respiratory rate to improve risk stratification in hemodynamically stable patients with acute pulmonary embolism.

Essentials In acute pulmonary embolism (PE), risk stratification is essential to drive clinical management. Improving the 2014-ESC risk stratification strategy is crucial in hemodynamically stable patients. Oxygen saturation and respiratory rate improve risk stratification in hemodynamically stable PE. Simple and routine tests improve risk stratification of hemodynamically stable PE. SUMMARY: Background In patients with acute pulmonary embolism (PE), risk stratification for short-term death is recommended to drive clinical management. A risk stratification strategy combining the simplified Pulmonary Embolism Severity Index (PESI), echocardiography and troponin was proposed by the European Society of Cardiology (ESC) in 2014. The identification of hemodynamically stable patients at increased risk of death by this strategy needs improvement. Objective To assess whether further stratification by serial cut-off values of oxygen saturation or respiratory rate improves the accuracy of the ESC risk stratification strategy in hemodynamically stable PE patients. Methods Prospective cohorts of hemodynamically stable patients with PE were merged in a collaborative database. The accuracy of risk stratification for 30-day mortality by the original and a modified 2014 ESC strategy was assessed. Results Overall, 255 patients (27%) were categorized as low, 510 (54%) as intermediate-low and 181 (19%) as intermediate-high risk according to the original 2014 ESC strategy. Thirty-day mortality was 1.2% in low, 10% in intermediate-low and 11% in intermediate-high-risk patients. By adding oxygen saturation in air of < 88%, the discriminatory power of the 2014 ESC model improved for 30-day mortality (c-statistics, 0.71; 95% confidence interval [CI], 0.65-0.77 vs. 0.63, 95% CI, 0.56-0.69) and for PE-related death (c-statistics, 0.75; 95% CI, 0.69-0.81 vs. 0.63, 95% CI 0.56-0.69). Conclusions Simple and routine tests, such as oxygen saturation or respiratory rate, could be added to the 2014 ESC strategy for risk stratification to identify hemodynamically stable PE patients at increased risk of death who are potentially candidates for more aggressive treatment.

Differential overexpression of SERPINA3 in human prion diseases.

Prion diseases are fatal neurodegenerative disorders with sporadic, genetic or acquired etiologies. The molecular alterations leading to the onset and the spreading of these diseases are still unknown. In a previous work we identified a five-gene signature able to distinguish intracranially BSE-infected macaques from healthy ones, with SERPINA3 showing the most prominent dysregulation. We analyzed 128 suitable frontal cortex samples, from prion-affected patients (variant Creutzfeldt-Jakob disease (vCJD) n = 20, iatrogenic CJD (iCJD) n = 11, sporadic CJD (sCJD) n = 23, familial CJD (gCJD) n = 17, fatal familial insomnia (FFI) n = 9, Gerstmann-Sträussler-Scheinker syndrome (GSS)) n = 4), patients with Alzheimer disease (AD, n = 14) and age-matched controls (n = 30). Real Time-quantitative PCR was performed for SERPINA3 transcript, and ACTB, RPL19, GAPDH and B2M were used as reference genes. We report SERPINA3 to be strongly up-regulated in the brain of all human prion diseases, with only a mild up-regulation in AD. We show that this striking up-regulation, both at the mRNA and at the protein level, is present in all types of human prion diseases analyzed, although to a different extent for each specific disorder. Our data suggest that SERPINA3 may be involved in the pathogenesis and the progression of prion diseases, representing a valid tool for distinguishing different forms of these disorders in humans.

The posterior bundle of the elbow medial collateral ligament: biomechanical study and proposal for a new reconstruction surgical technique.

BACKGROUND: The medial collateral ligament (MCL) is one of the primary elbows stabilizers. It is composed of an anterior bundle (AB), a posterior bundle (PB) and a transverse bundle. In elbow dislocations, until today MCL reconstruction has addressed the AB only. The purpose of this paper is to understand the biomechanical role of the PB of the MCL and to propose a new surgical technique for the simultaneous reconstruction of the anterior and posterior bundles, preventing the risk of recurrent posterior dislocation or posteromedial rotational instability (PMRI). MATERIALS AND METHODS: Sixteen cadaveric elbows were subjected to a force in compression, supination valgus and pronation varus. The residual stability was evaluated in three conditions: intact MCL, sectioned AB and sectioned AB + PB. The tests were performed in collaboration with the Department of Mechanical and Aerospace Engineering of the Politecnico di Torino. In six elbows, the MCL was then reconstructed with the new technique. RESULTS: Complete posterior elbow dislocation does not occur until the PB is sectioned. The section of the AB alone causes elbow instability in valgus stress, but not a dislocation. The reconstruction of the AB and the PB using the described technique allows a good recovery of range of motion and joint stability. CONCLUSIONS: The PB of the MCL has a primary role in elbow stability against valgus stress, and it prevents elbow posterior dislocation at all flexion angles. The described reconstruction technique should reduce the risk of residual PMRI.

Museum samples could help to reconstruct the original distribution of Salmo trutta complex in Italy.

Partial D-loop sequences of museum specimens of brown trout and marble trout (Salmo trutta species complex) collected from Mediterranean rivers in the late 19th century were analysed to help to describe the native distribution of these species. All the individuals studied carried native haplotypes, the geographic distribution of which is consistent with published data. These results indicate that museum specimens from the 19th century could represent an opportunity to get a picture of the original genetic diversity distribution of this species complex.

STANDING, a four-step bedside algorithm for differential diagnosis of acute vertigo in the Emergency Department.

Vertigo is generally due to a benign disorder, but it is the most common symptom associated with misdiagnosis of stroke. In this pilot study, we preliminarily assessed the diagnostic performance of a structured bedside algorithm to differentiate central from non-central acute vertigo (AV). Adult patients presenting to a single Emergency Department with vertigo were evaluated with STANDING (SponTAneous Nystagmus, Direction, head Impulse test, standiNG) by one of five trained emergency physicians or evaluated ordinarily by the rest of the medical staff (control group). The gold standard was a complete audiologic evaluation by a clinicians who are experts in assessing dizzy patients and neuroimaging. Reliability, sensibility and specificity of STANDING were calculated. Moreover, to evaluate the potential clinical impact of STANDING, neuroimaging and hospitalisation rates were compared with control group. A total of 292 patients were included, and 48 (16.4%) had a diagnosis of central AV. Ninety-eight (33.4%) patients were evaluated with STANDING. The test had good interobserver agreement (k = 0.76), with very high sensitivity (100%, 95%CI 72.3-100%) and specificity (94.3%, 95%CI 90.7-94.3%). Furthermore, hospitalisation and neuroimaging test rates were lower in the STANDING than in the control group (27.6% vs. 50.5% and 31.6% vs. 71.1%, respectively). In conclusion, STANDING seems to be a promising simple structured bedside algorithm that in this preliminary study identified central AV with a very high sensitivity, and was associated with significant reduction of neuroimaging and hospitalisation rates.

Systemic hypothermia in acute cervical spinal cord injury: a case-controlled study.

INTRODUCTION: Systemic hypothermia remains a promising neuroprotective strategy. There has been recent interest in its use in patients with spinal cord injury (SCI). In this article, we describe our extended single center experience using intravascular hypothermia for the treatment of cervical SCI. METHODS: Thirty-five acute cervical SCI patients received modest (33 °C) intravascular hypothermia for 48 h. Neurological outcome was assessed by the International Standards for Neurological Classification of Spinal Cord Injury scale (ISNCSCI) developed by the American Spinal Injury Association. Local and systemic complications were recorded. RESULTS: All patients were complete ISNCSCI A on admission, but four converted to ISNCSCI B in <24 h post injury. Hypothermia was delivered in 5.76 (±0.45) hours from injury if we exclude four cases with delayed admission (>18 h). Fifteen of total 35 patients (43%) improved at least one ISNCSCI grade at latest follow up 10.07 (±1.03) months. Even excluding those patients who converted from ISNCSCI A within 24 h, 35.5% (11 out of 31) improved at least one ISNCSCI grade. Both retrospective (n=14) and prospective (n=21) groups revealed similar number of respiratory complications. The overall risk of any thromboembolic complication was 14.2%. CONCLUSION: The results are promising in terms of safety and improvement in neurological outcome. To date, the study represents the largest study cohort of cervical SCI patients treated by modest hypothermia. A multi-center, randomized study is needed to determine if systemic hypothermia should be a part of SCI patients' treatment for whom few options exist.

A closer look into G protein coupled receptor activation: X-ray crystallography and long-scale molecular dynamics simulations.

G protein coupled receptors (GPCRs) are a large eukaryotic protein family of transmembrane receptors that react to a signal coming from the extracellular environment to generate an intracellular response through the activation of a signal transduction pathway mediated by a heterotrimeric G protein. Their diversity, dictated by the multiplicity of stimuli to which they respond and by the variety of intracellular signalling pathways they activate, make them one of the most prominent families of validated pharmacological targets in biomedicine. In recent years, major breakthroughs in structure determination of GPCRs have given new stimuli to the exploration of the biology of these proteins, providing a structural basis to understand the molecular origin of GPCR mechanisms of action. Based on the information coming from these structural studies, a number of recent in silico investigations used molecular dynamics (MD) simulations to contribute to our knowledge of GPCRs. In this review, we will focus on investigations that, taking advantage of the tremendous progress in both hardware and software, made testable hypotheses that have been validated by subsequent structural studies. These stateof- the-art molecular simulations highlight the potential of microsecond MD simulations as a valuable tool in GPCR structural biology and biophysics.

Comparison of two prognostic models for acute pulmonary embolism: clinical vs. right ventricular dysfunction-guided approach.

BACKGROUND: Recently, some prognostic models for acute pulmonary embolism (PE) have been proposed. We investigated whether the Pulmonary Embolism Severity Index (PESI) and the European Society of Cardiology (ESC) prognostic approaches result in different prognoses. METHODS: Consecutive adult patients with acute PE were included. According to the ESC guidelines, high-risk patients were identified by the presence of shock/hypotension, intermediate-risk patients by elevated troponin I or right ventricular dysfunction as assessed by echocardiography, and low-risk patients by the absence of any of the above. In the PESI model, 11 clinical variables, easily accessible at the bedside, were used to generate three risk classes. The main outcomes were all-cause and PE-related in-hospital mortality. RESULTS: Forty-one patients (8%, 95% confidence interval [CI] 5.8-10.8) of 510 died. According to the ESC model, 40% were at low risk of short-term mortality, 54% at intermediate risk, and 6% at high risk. The distribution according to the PESI model was 31% (P < 0.05 vs. ESC), 49% and 20% (P < 0.05 vs. ESC), respectively. Mortality increased through the risk classes (P < 0.01), without significant differences between the models. The ESC model identified with higher accuracy than the PESI model both high-risk and low-risk patients (P < 0.05 for both). When patients with shock/hypotension were excluded, the PESI model stratified patients into classes with increasing PE-related mortality (0.7%, 4.3%, and 11.6%, P < 0.05). Troponin I and right ventricular dysfunction added incremental prognostic value to the PESI model, particularly in normotensive patients at intermediate risk. CONCLUSIONS: The ESC model showed higher accuracy than the PESI model in identifying high-risk and low-risk patients. In normotensive patients, the PESI model could guide clinical management as well as troponin I and echocardiography testing.

Diagnostic accuracy of 64-slice CT in evaluating coronary artery bypass grafts and of the native coronary arteries.

PURPOSE: Our aim was to evaluate the accuracy, sensitivity and specificity of 64-slice multidetector computed tomography (MDCT) in the assessment of occlusions and stenoses of arterial and venous bypass grafts and disease progression in the native vessels distal to the graft, and to compare the results with those of conventional coronary angiography. MATERIALS AND METHODS: We enrolled 78 individuals (45 men, 33 women; mean age 59) and evaluated 213 bypass grafts using a 64-slice MDCT scanner. All patients underwent conventional coronary angiography with a mean time interval between the two examinations of 2 days. RESULTS: One patient was excluded due to arrhythmia during the examination. The 212 bypass grafts in the remaining 77 patients (98.7%) consisted of 115 (54%) venous grafts and 97 (46%) arterial grafts. In the 115 venous grafts, MDCT showed a sensitivity, specificity and accuracy of 100% in evaluating occluded grafts and a sensitivity of 94.4%, specificity of 98.4% and accuracy of 96.9% in evaluating significant stenoses. In evaluating occluded arterial grafts, sensitivity was 83.3%, specificity 100% and accuracy 98.9%, whereas in evaluating stenoses of arterial grafts, sensitivity was 100%, specificity 97.7% and accuracy 98%. CONCLUSIONS: Sensitivity, specificity and accuracy in evaluating native coronary vessels distal to the graft allow for a complete assessment of the surgical and native circulation. The examination appears therefore to be exhaustive in ruling out or confirming the presence of diseased vessels in the postoperative follow-up.

Contemporary management of adult intramedullary spinal tumors-pathology and neurological outcomes related to surgical resection.

STUDY DESIGN: Retrospective chart review and review of the recent literature. OBJECTIVES: To present our experience, over an 8-year period, with aggressive microsurgical resection of intramedullary spinal tumors in adults focusing on histology, microsurgical techniques, short-term neurological outcomes, complication avoidance and dorsal column dysfunction (DCD). SETTING: University of Miami/Jackson Memorial Medical Center Miami, FL, USA. METHODS: We conducted a retrospective review of a series of adult patients with intramedullary spinal tumors treated with microsurgical excision at the University of Miami/Jackson Memorial Medical Center between January 1997 and September 2005. RESULTS: Histologic analysis revealed a predominance of ependymomas (50%) with astrocytomas only comprising 12.5% of the tumors. We found no significant difference in pre- and postoperative McCormick grades. Although patients did not manifest significant motor weakness postoperatively as a result of surgery, 43.6% of patients exhibited the signs and symptoms of DCD, resulting in significant postoperative morbidity. CONCLUSION: We present a contemporary adult series of intramedullary spinal tumors. The most significant postoperative morbidity experienced by patients was DCD. The neurosurgeon should recognize the impact of these symptoms, prepare the patient and his/her family for the possibility of DCD, and minimize dorsal column manipulation in an attempt to decrease its prevalence.

Temporal sensitivity in a hemianopic visual field can be improved by long-term training using flicker stimulation.

BACKGROUND: Blindness of a visual half-field (hemianopia) is a common symptom after postchiasmatic cerebral lesions. Although hemianopia severely limits activities of daily life, current clinical practice comprises no training of visual functions in the blind hemifield. OBJECTIVE: To find out whether flicker sensitivity in the blind hemifield can be improved with intensive training, and whether training with flicker stimulation can evoke changes in cortical responsiveness. METHODS: Two men with homonymous hemianopia participated in the experiments. They trained with flicker stimuli at 30 degrees or with flickering letters at 10 degrees eccentricity twice a week for a year, and continued training with more peripheral stimuli thereafter. Neuromagnetic responses were registered at 1-2-month intervals, and the Goldmann perimetry was recorded before, during and after training. RESULTS: Flicker sensitivity in the blind hemifield improved to the level of the intact hemifield within 30 degrees eccentricity in one participant and 20 degrees eccentricity in the other. Flickering letters were recognised equally at 10 degrees eccentricity in the blind and intact hemifields. Improvement spread from the stimulated horizontal meridian to the whole hemianopic field within 30 degrees. Before training, neuromagnetic recordings showed no signal above the noise level in the hemianopic side. During training, evoked fields emerged in both participants. No changes were found in the Goldmann perimetry. DISCUSSION: Results show that sensitivity to flicker could be fully restored in the stimulated region, that improvement in sensitivity spreads to the surrounding neuronal networks, and that, during training, accompanying changes occurred in the neuromagnetic fields.

Training-induced cortical representation of a hemianopic hemifield.

BACKGROUND: Patients with homonymous hemianopia often have some residual sensitivity for visual stimuli in their blind hemifield. Previous imaging studies suggest an important role for extrastriate cortical areas in such residual vision, but results of training to improve vision in patients with hemianopia are conflicting. OBJECTIVE: To show that intensive training with flicker stimulation in the chronic stage of stroke can reorganise visual cortices of an adult patient. METHODS: A 61-year-old patient with homonymous hemianopia was trained with flicker stimulation, starting 22 months after stroke. Changes in functioning during training were documented with magnetoencephalography, and the cortical organisation after training was examined with functional magnetic resonance imaging (fMRI). RESULTS: Both imaging methods showed that, after training, visual information from both hemifields was processed mainly in the intact hemisphere. The fMRI mapping results showed the representations of both the blind and the normal hemifield in the same set of cortical areas in the intact hemisphere, more specifically in the visual motion-sensitive area V5, in a region around the superior temporal sulcus and in retinotopic visual areas V1 (primary visual cortex), V2, V3 and V3a. CONCLUSIONS: Intensive training of a blind hemifield can induce cortical reorganisation in an adult patient, and this case shows an ipsilateral representation of the trained visual hemifield in several cortical areas, including the primary visual cortex.

Retinotopic distribution of chromatic responses in human primary visual cortex.

In non-human primates at least three anatomically and functionally distinct channels convey signals from the retina to the primary visual cortex (V1). Two of these channels, the parvocellular and the koniocellular, are sensitive to chromatic contrasts and form the basis of color vision. In humans, common phylogenetic history with other primates and psychophysical experiments suggest identical retinocortical mechanisms but separate evaluation of the distinct anatomical channels has been difficult because signals are already combined in V1. We studied the spatial distribution of activation to chromatic stimuli along the two opponent chromatic axes in human V1 with multifocal functional magnetic resonance imaging. The signal strength was quantified from three experiments with stimuli up to 20 degrees eccentricity. The hypothesis was that, although the parvo- and koniocellular signals are mixed in V1, distinct distributions of signal strength would be evident. We found that whereas different conditions activated the same areas of cortex, indicating that they have identical magnification factors, the responses to red/green stimulation were stronger close to the fovea whereas the blue/yellow responses were much less diminished with increasing eccentricity. Both chromatic axes showed saturating contrast response functions. Our measure directly from human V1 is in line with earlier psychophysical studies suggesting relatively stronger parvocellular channel representation close to the fovea, and more uniform distribution of the koniocellular and achromatic channels. In addition, our study presents a way to rapidly quantify retinotopic signal transmission in distinct retinocortical pathways of individual subjects.

Multifocal fMRI mapping of visual cortical areas.

The multifocal mapping of electroretinograms and visual evoked potentials has established an important role in both basic research and in diagnostic procedures. We have developed a multifocal mapping method for fMRI, which allows detailed analysis of multiple local visual field representations in the cortex with excellent spatial resolution. Visual field was divided into 60 regions in a dartboard configuration, scaled according to the human magnification factor. Within blocks of 7 s, half of the regions were stimulated with checkerboard patterns contrast reversing at 8 reversals per second, while the other half remained inactive at uniform luminance. The subset of active regions changed with each 7-s block, according to an orthogonal design. Functional MRI was done with a 3-T GE Signa and analyzed with SPM2. A general linear model was fitted producing activation maps for each of the 60 regions, and local signal changes were quantified from V1. These activation maps were next assigned to 3D surface models of the cortical sheet, and then unfolded, using the Brain à la Carte software package. Phase-encoded retinotopic analysis of conventional design served as qualitative comparison data. With multifocal fMRI, all regions were mapped with good signal-to-noise ratio in V1, and subsets of regions showed activation in V2 and V3. This method allows rapid and direct exploration of multiple local visual responses, and is thus able to give complementary information to phase encoded mapping of retinotopic areas.

High-dose methylprednisolone may cause myopathy in acute spinal cord injury patients.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: Although Bracken et al have demonstrated a significant neuroprotective effect of high-dose intravenous (i.v.) methylprednisolone (MP) within 8 h post spinal cord injury (SCI), this practice has recently been challenged. We hypothesized it is possible that acute corticosteroid myopathy (ACM) may occur secondary to the MP. This pilot study was performed to test this hypothesis. SETTING: University of Miami School of Medicine/Jackson Memorial Hospital, Miami VA Medical Center, FL, USA. METHODS: Subjects included five nonpenetrating traumatic SCI patients, who received 24 h MP according to National Acute Spinal Cord Injury Studies (NASCIS) protocol, and three traumatic patients who suffered SCI and did not receive MP. Muscle biopsies and electromyography (EMG) were performed to determine if myopathic changes existed in these patients. RESULTS: Muscle biopsies from the SCI patients who received 24 h of MP showed muscle damage consistent with ACM in four out of five cases. EMG studies demonstrated myopathic changes in the MP-treated patients. In the three patients who had SCI but did not receive MP, muscle biopsies were normal and EMGs did not reveal evidence of myopathy. CONCLUSION: Our data suggest that MP in the dose recommended by the NASCIS may cause ACM. If this is true, part of the improvement of neurological recovery showed in NASCIS may be only a recording of the natural recovery of ACM, instead of any protection that MP offers to the injured spinal cord.

Mild hypothermia, blood loss and complications in elective spinal surgery.

BACKGROUND CONTEXT: Spinal surgery carries risks of incidental spinal cord and nerve root injury. Neuroprotection, to minimize the extent of such injuries, is desirable. However, no neuroprotective strategies have been conclusively validated in nonvascular spinal surgery. Mild hypothermia resulting from general anesthesia is a readily achievable potential neuroprotective strategy. Mild hypothermia, however, has been associated with wound infection, increased operative blood loss and other complications. No previous studies have specifically evaluated whether mild hypothermia is associated with an increased risk of these complications in elective spinal surgery. PURPOSE: We investigated the association between incidental mild hypothermia, perioperative complications and operative blood loss. STUDY DESIGN/SETTING: This is a retrospective study employing cohort analysis, rank analysis and single and multivariate linear regression. The setting was the Veterans Administration Medical Center, a teaching hospital of the University of Miami. PATIENT SAMPLE: Data on a total of 70 adult veterans aged 23 to 81 years undergoing complex spinal procedures in which passive cooling was employed during surgical decompression. OUTCOME MEASURES: The variables measured were temperature, blood loss, mean arterial pressure (MAP) and duration of anesthesia. The outcome measured was the presence or absence of complications. METHODS: After 70 patients had been acquired, regression and rank analyses were performed to test for a link between mild hypothermia and blood loss. In addition, two cohorts, patients who experienced complications, and those who did not experience complications in the perioperative period, were compared for several variables including three measures of exposure to hypothermia. Surgical procedures included 60 cervical, 1 occipitocervical, 1 cervicothoracic, 7 thoracic and 1 thoracolumbar procedure. Hypothermia followed induction of anesthesia; esophageal or bladder temperature was monitored. Cooling was passive; warming utilized a forced air blanket. Temperature data from anesthetic records was used to derive mean intraoperative temperature, nadir intraoperative temperature and the rates of cooling and rewarming. The time course of hypothermia, the overall fluctuation in core temperature and the quantity of subbaseline temperature were determined. Medical and surgical complications were included. Two patients with complications considered irrelevant to hypothermia were removed from further analysis. Patients with and without complications were compared as cohorts for differences in mean values of age, comorbid risk factors, intraoperative MAP, intraoperative blood loss, anesthetic duration and temperature-related measures. Relationships between blood loss, anesthesia duration and temperature parameters were assessed in rank and regression analyses. RESULTS: Patients with complications (n=12) had longer mean anesthetic durations (p=.0001) and larger mean surgical blood losses (p=.001) than patients without complications (n=56). Neither mean nor nadir intraoperative hypothermic temperatures were statistically associated with complications. However, large hypothermic integrals (p=.04) and the total quantity of recorded temperature fluctuation (p=.01) were both associated with complications. Comorbid risk factors, MAP and age were not statistically linked to complications. Finally, no relationship between any of the temperature measures and increased blood loss was found. CONCLUSION: Operative blood loss was not linked to any index of the patient's temperature. Longer anesthesia durations were linked to complications and increased blood loss. Regarding mild hypothermia, neither mean nor nadir hypothermic temperatures were linked to complications, but the estimated total quantity of subbaseline temperature was linked, as was total fluctuation in temperature. Lengthy exposure to mild hypothermia appeared to be associated with wound infections. The use of mild hypothermia as a potential neuroprotective strategy during spinal surgery appears to be reasonably safe, but to avoid complications, the duration of hypothermic exposure should be minimized.

Sequence of pattern onset responses in the human visual areas: an fMRI constrained VEP source analysis.

We measured the timing of activity in distinct functional areas of the human visual cortex after onset of a visual pattern. This is not possible with visual evoked potentials (VEPs) or magnetic fields alone, and direct combination of functional magnetic resonance imaging (fMRI) with electromagnetic data has turned out to be difficult. We tested a relatively new approach, where both position and orientation of the active cortex was given to the VEP source model. Subjects saw the same visual patterns flashed ON and OFF, both when recording VEPs and fMRI responses. We identified the positions and orientations of the activated cortex in four retinotopic areas in each individual, and the corresponding dipoles were seeded to model the individual evoked potential data. Unexplained variance, comprising signals from other areas, was inversely modeled. Despite the partially a priori fixed model and optimized signal-to-noise ratio of VEP data, full separation of retinotopic areas was only seldom possible due to crosstalk between the adjacent sources, but separation was usually possible between areas V1 and V3/V3a. Whereas the latencies generally followed the hierarchical organization of cortical areas (V1-V2-V3), with around 25 ms between the strongest responses, an early activation emerged 10-20 ms after V1, close to the temporo-occipital junction (LO/V5) and with an additional 20-ms latency in the corresponding region of the opposite hemisphere. Our approach shows that it is feasible to directly seed information from fMRI to electromagnetic source models and to identify the components and dynamics of VEPs in different retinotopic areas of a human individual.

Timing of interactions across the visual field in the human cortex.

While it is generally believed that interactions across long distances in the visual field occur only in the higher-order cortical areas, other results suggest that such interactions are processed very early. In the preceding paper, we identified the latencies within a subset of cortical areas in the human visual system. In the present study, we test in which areas and at which latencies the responses to two visual patterns start interacting. We used functional magnetic resonance imaging directly combined with visual-evoked potential source analysis. Interactions appeared first anterolaterally to the retinotopic areas, at 80 ms for two stimuli presented in the left lower visual quadrant and at 100 ms for symmetrical stimulation of both lower quadrants. In the lateral occipital-V5 region (LOV5), two patterns presented simultaneously in one quadrant elicited a response with shorter latency and infra-linear addition of the amplitudes compared with the patterns presented separately. For bilateral stimulation, the timing of the LOV5 response coincided with the response to contralateral stimulation alone. Other visual areas showed interactions appearing later than within LOV5: starting at 150 ms in V1, at 120 ms in V3-V3a for the left visual hemifield stimulation and at 160 ms for both visual hemifields stimulation. Our data show that distinct patterns in the visual field interact first in LOV5, suggesting that this region must be the first to pool spatial information across the whole visual field.

Impairment of cardiopulmonary receptor sensitivity in the early phase of heart failure.

OBJECTIVES: To characterise the efficiency of the cardiopulmonary baroreflex system in the early phase of heart failure and its relation to limitation of physical activity. DESIGN: Forearm blood flow (venous occlusion plethysmography), vascular resistance, and central venous pressure (CVP), estimated from an antecubital vein, were measured in the supine position at baseline and 15 minutes after application of lower body negative pressure at -7 and -14 mm Hg (receptor downloading) or leg raising (receptor loading). SUBJECTS: Heart failure patients without limitation (NYHA class I; n = 18) or with slight limitation of physical activity (NYHA class II; n = 13), and 11 healthy controls. RESULTS: The efficiency of the cardiopulmonary baroreflex function, expressed by the slope of the relation between CVP changes and the corresponding changes of calculated forearm vascular resistance (gain), was reduced both in NYHA class I patients (mean (SD) -1.99 (0.83) v -2.78 (0.66) in controls; p < 0.05) and NYHA class II patients (-1.29 (0.5); p<0.001 v controls). However, change in peripheral vascular resistance during preload increase was similar in controls (-3.3 (0.9) units) and in NYHA class I patients (-3.3 (2.1) units; NS v controls), and was significantly reduced only in NYHA class II patients (-1.6 (1.3) units, p < 0.03 v controls). The gain in the cardiopulmonary reflex was related to the distance walked during the six minute corridor test. CONCLUSIONS: A reduced tonic efficacy of the cardiopulmonary reflex system is already detectable in the early phase of heart failure, the impairment in acute response to preload increase being detectable only in symptomatic patients.