The psychological burden of disease among patients undergoing cervical spine surgery: Are we underestimating our patients' inherent disability?

BACKGROUND: Studies have utilized psychological questionnaires to identify the psychological distress among certain surgical populations. RESEARCH QUESTION: Is there an additional psychological burden among patients undergoing surgical treatment for their symptomatic degenerative cervical disease? MATERIALS AND METHODS: Patients>18 years of age with symptomatic, degenerative cervical spine disease were included and prospectively enrolled. Correlations and multivariable logistic regression analysis assessed the relationship between these mental health components (PCS, FABQ) and the severity of disability described by the NDI, EQ-5D, and mJOA score. Patient distress scores were compared to previously published benchmarks for other diagnoses. RESULTS: 47 patients were enrolled (age: 56.0 years,BMI: 29.7kg/m2). Increasing neck disability and decreasing EQ-5D were correlated with greater PCS and FABQ(all P<0.001). Patients with severe psychological distress at baseline were more likely to report severe neck disability, while physician-reported mJOA had weaker associations. Compared to historical controls of lumbar patients, patients in our study had greater levels of psychological distress, as measured by FABQ (40.0 vs. 17.6; P<0.001) and PCS (27.4 vs. 19.3;P<0.001). DISCUSSION AND CONCLUSION: Degenerative cervical spine patients seeking surgery were found to have a significant level of psychological distress, with a large portion reporting severe fear avoidance beliefs and catastrophizing pain at baseline. Strong correlation was seen between patient-reported functional metrics, but less so with physician-reported signs and symptoms. Additionally, this population demonstrated higher psychological burden in certain respects than previously identified benchmarks of patients with other disorders. Preoperative treatment to help mitigate this distress, impact postoperative outcomes, and should be further investigated. LEVEL OF EVIDENCE: Level III.

Particle-size dependent bactericidal activity of magnesium oxide against Xanthomonas perforans and bacterial spot of tomato.

Bacterial spot, caused by Xanthomonas spp., is a highly destructive disease of tomatoes worldwide. Copper (Cu) bactericides are often ineffective due to the presence of Cu-tolerant strains. Magnesium oxide (MgO) is an effective alternative to Cu bactericides against Xanthomonas spp. However, the effects of particle size on bactericidal activity and fruit elemental levels are unknown. In this study, nano (20 nm) and micron (0.3 and 0.6 µm) size MgO particles were compared for efficacy. Nano MgO had significantly greater in vitro bactericidal activity against Cu-tolerant X. perforans than micron MgO at 25-50 µg/ml. In field experiments nano and micron MgO applied at 200 and 1,000 µg/ml were evaluated for disease control. Nano MgO at 200 µg/ml was the only treatment that consistently reduced disease severity compared to the untreated control. Inductively Coupled Plasma Optical Emission Spectroscopy revealed that nano MgO applications did not significantly alter Mg, Cu, Ca, K, Mn, P and S accumulation compared to fruits from the untreated plots. We demonstrated that although both nano MgO and micron MgO had bactericidal activity against Cu-tolerant strains in vitro, only nano MgO was effective in bacterial spot disease management under field conditions.

Comparing "intra operative" tissue engineering strategies for the repair of craniofacial bone defects.

BACKGROUND: In craniofacial reconstruction, the gold standard procedure for bone regeneration is the autologous bone graft (BG). However, this procedure requiring bone harvesting is a source of morbidity. Bone substitutes, such as biphasic calcium phosphate (BCP), represent an interesting alternative but are not sufficient for bone healing in hypoplastic conditions. In such conditions, osteoprogenitors are essential to provide osteoinduction. Previous studies have shown that BCP associated with total bone marrow (TBM) provides same bone reconstruction as bone graft in a rat model of calvaria defect. Furthermore, adipose tissue stromal vascular fraction (SVF) seems to be another promising source of osteoprogenitor cells that can be used intra-operatively. This study aimed to combine, intra-operative BCP-based bone tissue engineering strategies with TBM or SVF from human sources. METHODS: 5 mm critical-size calvaria defects were performed in 18 nude rat. The defects were filled with intra-operative bone tissue engineering procedures: human BG, human TBM + BCP, human SVF + BCP and, rat TBM + BCP. Animals were sacrificed 8 weeks after implantation and calvaria were processed for histological and radiological examinations. Implanted cells were labelled with a fluorochrome. RESULTS: Micro-CT analysis revealed partial repair of bone defect. Only hBG significantly succeeded in healing the defect (43.1%). However, low rate of newly formed bone tissue was observed in all tissue engineering conditions (hTBM, hSVF, ratTBM). DISCUSSION: The lack of bone formation observed in this study could possibly be attributed to the model. CONCLUSION: This study combined with a literature analysis show the stringency of the nude rat calvaria model in term of bone regeneration.

Nano-Magnesium Oxide: A Novel Bactericide Against Copper-Tolerant Xanthomonas perforans Causing Tomato Bacterial Spot.

Bacterial spot caused by Xanthomonas perforans causes significant damage on tomato in Florida. Due to the presence of copper (Cu)-tolerant X. perforans strains, Cu bactericides are not effective in disease management. Hence, there is a critical need to find alternatives for Cu. Antibacterial activity of magnesium oxide (Nano-MgO), and other metal oxide nanoparticles, were evaluated against a Cu-tolerant and -sensitive X. perforans strain. In vitro experiments demonstrated high antibacterial activity of Nano-MgO against both strains compared with the commercial Cu. The minimum inhibitory concentration of Nano-MgO is 25 µg/ml and the minimum bactericidal concentration is 100 µg/ml against a Cu-tolerant X. perforans strain after 4 h of exposure. Structural changes in the bacterial membrane following exposure to Nano-MgO treatments compared with the controls were observed using transmission electron microscopy. In two greenhouse experiments with a Cu-tolerant strain, bacterial spot severity was significantly reduced by Nano-MgO at 200 µg/ml compared with Cu-ethylene bis-dithiocarbamate (grower standard), and the untreated control (P = 0.05). In three field experiments, Nano-MgO at 200 µg/ml significantly reduced disease severity with no negative impact on yield compared with the untreated control. Inductively coupled plasma mass spectrometric analysis of the fruit confirmed that Nano-MgO application did not lead to the accumulation of Mg, Cu, Ca, K, Mn, P, and S. This study is the first to demonstrate the potential of Nano-MgO against bacterial spot of tomato.

Event-related brain potentials reveal correlates of the transformation of stimulus functions through derived relations in healthy humans.

This research aimed to explore the neural correlates of relational learning by recording high-density EEG during a behavioural task involving derivation levels of varying complexity. A total of 15 participants (5 male; age range 18-23 years; mean age=20.0 years) completed contextual cue training, relational learning, function training and a derivation task while 128-channel event-related potentials (ERPs) were recorded from the scalp (Background). Differences in response latencies were observed between the two derived (symmetry and equivalence) and directly trained relations, with longest latencies found for equivalence and shortest for the directly trained relations. This pattern failed to reach statistical significance. Importantly, ERPs revealed an early P3a positivity (from 230 to 350ms) over right posterior scalp sites. Significantly larger mean amplitudes were found at three channels (P6, E115 and E121) for the equivalence relations compared to the two other types (Results). We believe this may constitute a first demonstration of differences in brain electrophysiology in the transformation of stimulus functions through derived relations of hierarchical levels of complexity (Conclusions).

De la biología al injerto de tejido adiposo: cómo mejorar el lipoinjerto / From biology to fat grafting: how to improve lipofilling

A pesar de que el uso del injerto de grasa ha ganado popularidad, no hay consenso sobre la mejor manera de manejar el tejido adiposo. Los protocolos difieren y los resultados son a menudo variables. Diversos factores influyen en la calidad de la grasa inyectada, entre los que encontramos las moléculas tóxicas provenientes de la infiltración, procedimiento previo a la liposucción. En este trabajo, hemos confirmado el efecto nocivo de los anestésicos sobre las células madre derivadas del tejido adiposo, determinando el efecto del lavado y la centrifugación en el tejido graso con el fin de proponer un protocolo simple y optimizado para mejorar la supervivencia del injerto. Evaluamos la citotoxicidad de la lidocaína sobre las células madre derivadas de tejido adiposo (ADSC) mediante ensayo de LDH. Sometimos el tejido adiposo conjunto a varios tipos de centrifugación (de 1 segundo a 10minutos y desde 0 g a 1800 g), y el volumen de líquido y el aceite liberado se midió inmediatamente después de la centrifugación. Tras la determinación de las condiciones óptimas para la manipulación de tejidos (400 g/1 minuto), inyectamos el tejido adiposo de liposucción sin o con lidocaína en ratones inmunodeficientes. Un mes después de la inyección, evaluamos la calidad de los injertos mediante histología, y en comparación con los injertos obtenidos a partir de un protocolo convencional: una simple sedimentación. La lidocaína ejerce un efecto citotóxico sobre las ADSC, y este efecto depende del tiempo de incubación y de las concentraciones. En cuanto al tejido adiposo, una centrifugación intensa (900 g, 1800 g) es perjudicial en comparación con una centrifugación suave (100 g, 400 g). Además, las secciones histológicas de los injertos de tejido adiposo no centrifugados mostraron la presencia de grandes vacuolas de aceite mientras que los injertos resultantes de lavado con protocolo de centrifugación suave (400g/1minuto) no lo hacen. En conclusión, creemos que se debe emplear un manejo adecuado del tejido adiposo, incluyendo lavado y centrifugación, con el fin de eliminar el líquido de infiltración y las moléculas tóxicas asociadas que son perjudiciales para los injertos. Sin embargo, no recomendamos una centrifugación intensa ya que conduce muy rápidamente a una mayor muerte celular. Por lo tanto, una centrifugación suave (400 g/1 minuto) precedida de lavados, parece ser el protocolo más apropiado para la reinyección del tejido adiposo

While fat grafting for soft tissue filling has gained popularity, there is no consensus on the best way how to handle adipose tissue. Protocols differ and results are often highly variable. Various factors influence the quality of injected fat, among which the toxic molecules coming from infiltration procedure prior to liposuction. In this work, we have confirmed the deleterious effect of anesthetics on adipose-derived stem cells, and determined the effect of washing and centrifugation on adipose tissue, in order to propose a simple and optimized protocol to improve graft survival. Lidocaine cytotoxicity on adipose-derived stem cells (ADSCs) was evaluated by LDH assay. Then, whole adipose tissue was subjected to various centrifugation types (from 1 sec to 10 min and from 0 g to 1800 g), and volumeof liquid and oil released were measured immediately after centrifugation. After determination of the optimal conditions for tissue handling (400 g/1 min),adipose tissue from liposuction made without or with lidocaine was injected into immunodeficient mice. One month after injection, quality of the grafts was evaluated by histology, and compared with grafts obtained from one conventional protocol: a simple settling. Lidocaine exerts a cytotoxic effect on ADSCs, and this effect is dependent on the incubation time and concentrations. Concerning adipose tissue, strong centrifugation (900 g, 1800 g) is deleterious compared to the low centrifugation(100 g, 400 g). In addition, histological sections of the non-centrifuged adipose tissue grafts shows the presence of extensive oil vacuoles, whereas the grafts resulting from washing with soft centrifugation protocol (400 g/1 min) do not. To conclude that appropriate handling of adipose tissue, including washing and centrifugation, should be done in order to remove infiltration liquid and associated toxic molecules, which are deleterious for the grafts. However, strong centrifugation is not recommended since it leads very quickly to greater cell death. Thus, soft centrifugation (400 g/1 min), preceded by washings, seems to be the most appropriate protocol for the re-injection of adipose tissue

Incidence of occupational exposures in a tertiary health care center.

INTRODUCTION: Occupational exposure to Hepatitis B virus (HBV), human immunodeficiency virus (HIV) and Hepatitis C virus (HCV) infection is a cause of concern to all health care workers (HCWs), especially those, in hospitals. Among the HCWs, nurses, interns, technicians, resident doctors and housekeeping staff have the highest incidence of occupational exposure. AIMS: To analyze the cases of needle stick injuries and other exposures to patient's blood or body fluids among health care workers. MATERIALS AND METHODS: A detailed account of the exposure is documented which includes incidence of needle stick injuries (NSI) and implementation of post-exposure prophylaxis (PEP) as per the hospital guidelines. We report a two-year continuing surveillance study where 255 health care workers (HCWs) were included. PEP was given to HCWs sustaining NSI or exposures to blood and body fluids when the source is known sero-positive or even unknown where the risk of transmission is high. Follow-up of these HCW's was done after three and six months of exposure. RESULTS: Of the 255 HCWs, 59 sustained needle stick injuries and two were exposed to splashes. 31 of the NSI were from known sources and 28 from unknown sources. From known sources, thirteen were seropositive; seven for HIV, three for HCV and three for HBV. Nineteen of them sustained needle stick during needle re-capping, six of them during clean up, six of them while discarding into the container, 17 during administration of injection, eight of them during suturing, two occurred in restless patient, 17 during needle disposal. CONCLUSION: So far, no case of sero-conversion as a result of needle stick injuries was reported at our center.

Dengue virus identification by transmission electron microscopy and molecular methods in fatal dengue hemorrhagic fever.

Dengue virus is the most significant virus transmitted by arthropods worldwide and may cause a potentially fatal systemic disease named dengue hemorrhagic fever. In this work, dengue virus serotype 4 was detected in the tissues of one fatal dengue hemorrhagic fever case using electron immunomicroscopy and molecular methods. This is the first report of dengue virus polypeptides findings by electron immunomicroscopy in human samples. In addition, not-previously-documented virus-like particles visualized in spleen, hepatic, brain, and pulmonary tissues from a dengue case are discussed.

Facial emotion recognition in adolescents with psychotic-like experiences: a school-based sample from the general population.

BACKGROUND: Psychotic symptoms, also termed psychotic-like experiences (PLEs) in the absence of psychotic disorder, are common in adolescents and are associated with increased risk of schizophrenia-spectrum illness in adulthood. At the same time, schizophrenia is associated with deficits in social cognition, with deficits particularly documented in facial emotion recognition (FER). However, little is known about the relationship between PLEs and FER abilities, with only one previous prospective study examining the association between these abilities in childhood and reported PLEs in adolescence. The current study was a cross-sectional investigation of the association between PLEs and FER in a sample of Irish adolescents. METHOD: The Adolescent Psychotic-Like Symptom Screener (APSS), a self-report measure of PLEs, and the Penn Emotion Recognition-40 Test (Penn ER-40), a measure of facial emotion recognition, were completed by 793 children aged 10-13 years. RESULTS: Children who reported PLEs performed significantly more poorly on FER (ß=-0.03, p=0.035). Recognition of sad faces was the major driver of effects, with children performing particularly poorly when identifying this expression (ß=-0.08, p=0.032). CONCLUSIONS: The current findings show that PLEs are associated with poorer FER. Further work is needed to elucidate causal relationships with implications for the design of future interventions for those at risk of developing psychosis.

Surfactant-promoted Prussian Blue-modified carbon electrodes: enhancement of electro-deposition step, stabilization, electrochemical properties and application to lactate microbiosensors for the neurosciences.

We report here for the first time a comparison of the beneficial effects of different cationic surfactants - cetyl trimethyl ammonium bromide (CTAB), benzethonium chloride (BZT) and cetylpyridinium chloride (CPC) - for the electrochemical synthesis of Prussian Blue (PB) films, using cyclic voltammetry (CV), on screen-printed carbon electrodes (SPCEs). Their electrochemical properties were investigated, paying special attention to parameters such as the amount of PB deposited, film thickness, charge transfer rate, permeability, reversibility, stability and sensitivity to hydrogen peroxide detection. All surfactant-enhanced PB-modified SPCEs displayed a significant improvement in their electrochemical properties compared with PB-modified SPCEs formed in the absence of surfactants. Surfactant-modified electrodes displayed a consistently higher PB surface concentration value of 2.1±0.4×10(-8) mol cm(-2) (mean±SD, n=3) indicating that PB deposition efficiency was improved 2-3 fold. K(+) and Na(+) permeability properties of the films were also studied, as were kinetic parameters, such as the surface electron transfer rate constant (k(s)) and the transfer coefficient (α). The hydrogen peroxide sensitivity of surfactant-modified PB films generated by 10 electro-deposition CV cycles gave values of 0.63 A M(-1) cm(-2), which is higher than those reported previously for SPCEs by other authors. Finally, the first lactate microbiosensor described in the literature based on BZT-modified PB-coated carbon fiber electrodes is presented. Its very small cross-section (~10 µm diameter) makes it particularly suitable for neuroscience studies in vivo.

Simultaneous measurements of glucose, oxyhemoglobin and deoxyhemoglobin in exposed rat cortex.

The present work addresses the simultaneous monitoring of hemoglobin and glucose consumption in rat somatosensory cortex in vivo. We propose a method which combines two techniques: 2-dimensional optical imaging and an amperometric microbiosensor. The mounted setup optimizes the space in the cranial window so that three micro-electrodes can be inserted: glucose microbiosensor, sentinel and stimulating electrode as well as the holder to manipulate the optical fiber. Additionally, a tool based on graphical user interface programming has been developed to visualize a two-dimension spectral map of oxy-, deoxy- and total hemoglobin, HbO2, HbR and HbT respectively, in the cortex. Our results showed a good sensitivity, selectivity and spatial resolution for both methods. Relevant hemodynamic responses had a common central focus (at the site of the stimulus) which later segregated to other vascular compartments. A good linear relationship between extracellular glucose concentration and HbO2 values during brain activation after local electrical stimulation was observed for electrochemical and optical recordings (R² values were over 0.94). Time courses between glucose and HbO2 signals showed a temporal delay ranging from 1 s to 2 s, suggesting that both variables are not always coupled. The temporal mismatching reported here, provides in vivo evidence that supports a neuronal hypothesis: cerebral blow flow and oxidative metabolism are driven in parallel by neural activity--rather than a concatenation of events ('in-series' events) occurring at sites of neuronal activation.

Microbiosensors for glucose based on Prussian Blue modified carbon fiber electrodes for in vivo monitoring in the central nervous system.

Carbon fiber electrodes (CFEs) were used to develop microbiosensors for glucose as an alternative to the classical Pt and Pt-Ir transducers. Their low dimensions (∼250 µm CFE length and ∼10 µm diameter) are important factors for measurements in physiological environments. An electrocatalytic Prussian Blue (PB) film facilitated detection of enzyme-generated hydrogen peroxide at a low applied potential (∼0.0 V against SCE), contrasting the high potential used in many previous designs (∼0.7 V). The electrosynthesized polymer, poly-o-phenylenediamine (PoPD), was used to improve biosensor stability and selectivity against endogenous interference species, such as ascorbic and uric acids. Optimization of the fabrication procedure is described, including activation of CFE/PB, enzyme immobilization and stabilization, anti-interference films, optimizing applied potential, and pH effects. Analytical properties were also characterized such as sensitivity, LOD, linear range, and enzyme loading. Finally, an optimized biosensor displaying a linear sensitivity of 9.3±0.1 µA mM(-1) cm(-2) (n=3), a 2% RSD and free of interference, is proposed as a suitable candidate for in vivo glucose monitoring in the CNS.

Chondroitin sulfate modulation of matrix and inflammatory gene expression in IL-1beta-stimulated chondrocytes--study in hypoxic alginate bead cultures.

OBJECTIVE: To determine the effect of avian chondroitin sulfate (CS) on interleukin-1beta (IL-1beta)-induced expression of genes related to catabolic, anabolic and inflammatory aspects in chondrocytes cultured in hypoxic alginate beads. DESIGN: Articular chondrocytes from bovine metacarpal joint were isolated and cultured in alginate beads, using low oxygen atmosphere (5% O2). After 1-week exposure to CS (1, 10 and 100microg/ml), they were treated by recIL-1beta (10ng/ml) for 24 or 48h, in the presence of CS. RNA was extracted and used to determine, by quantitative reverse transcription-polymerase chain reaction, the steady-state levels of mRNAs encoding several genes related to anabolic, catabolic and inflammatory aspects. Glycosaminoglycan (GAG) synthesis was also assayed by 35S-sulfate incorporation. RESULTS: CS decreased IL-1beta-induced expression of matrix metalloproteases-1, -3 and -13 and aggrecanases-1 and -2. It slightly enhanced the aggrecan core protein mRNA and the GAG synthesis. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA levels were found to be reduced by CS treatment. However, no CS-induced decrease of NO was observed in IL-1beta-treated chondrocytes, whereas prostaglandin E2 production was diminished in correlation with the COX-2 mRNA amounts. Furthermore, CS was capable of counteracting IL-1beta-depressed expression of transforming growth factor-beta (TGF-beta) receptors. CONCLUSIONS: CS can repress expression of genes encoding proteolytic enzymes involved in cartilage degradation. It also inhibits IL-1beta-induced expression of the pro-inflammatory genes iNOS and COX-2 and restores TGF-beta receptors I and II (TGF-betaRI and RII) mRNA levels. These data suggest that CS may exert both chondroprotective and anti-inflammatory limited effects on articular cartilage that could have long-term beneficial action on the osteoarthritic process.

Role and regulation of acylethanolamides in energy balance: focus on adipocytes and beta-cells.

The endocannabinoid, arachidonoylethanolamide (AEA), and the peroxisome proliferator-activated receptor (PPAR)-alpha ligand, oleylethanolamide (OEA) produce opposite effects on lipogenesis. The regulation of OEA and its anti-inflammatory congener, palmitoylethanolamide (PEA), in adipocytes and pancreatic beta-cells has not been investigated. We report here the results of studies on acylethanolamide regulation in these cells during obesity and hyperglycaemia, and provide an overview of acylethanolamide role in metabolic control. We analysed by liquid chromatography-mass spectrometry OEA and PEA levels in: 1) mouse 3T3F442A adipocytes during insulin-induced differentiation, 2) rat insulinoma RIN m5F beta-cells kept in 'low' or 'high' glucose, 3) adipose tissue and pancreas of mice with high fat diet-induced obesity (DIO), and 4) in visceral fat or blood of obese or type 2 diabetes (T2D) patients. In adipocytes, OEA levels remain unchanged during differentiation, whereas those of PEA decrease significantly, and are under the negative control of both leptin and PPAR-gamma. PEA is significantly downregulated in subcutaneous adipose tissue of DIO mice. In RIN m5F insulinoma beta-cells, OEA and PEA levels are inhibited by 'very high' glucose, this effect being enhanced by insulin, whereas in cells kept for 24 h in 'high' glucose, they are stimulated by both glucose and insulin. Elevated OEA and PEA levels are found in the blood of T2D patients. Reduced PEA levels in hypertrophic adipocytes might play a role in obesity-related pro-inflammatory states. In beta-cells and human blood, OEA and PEA are down- or up-regulated under conditions of transient or chronic hyperglycaemia, respectively.

Antibodies from patients with dengue viral infection mediate cellular cytotoxicity.

Acute and late convalescent sera (collected at day 5 of disease onset and 1 year later) from dengue fever (DF) and dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) laboratory confirmed cases, were tested for antibody-dependent cell-mediated cytotoxicity (ADCC) activity using dengue 1 (DENV-1) or dengue 2 (DENV-2) infected cells as target. All patients experienced their first dengue virus (DENV) infection 20 years before. ADCC activity was detected in acute sera from DHF/DSS but not in sera from DF patients. However, 1 year after illness, ADCC activity was observed in all cases. This preliminary report represents one of the few studies of ADCC in dengue patients and suggests that ADCC could be implicated in dengue pathogenesis.

Q2 dependence of the neutron spin structure function g2(n) at low Q2.

We present the first measurement of the Q2 dependence of the neutron spin structure function g2(n) at five kinematic points covering 0.57 (GeV/c)2 < or = Q2 < or = 1.34 (GeV/c)2 at x approximately = 0.2. Though the naive quark-parton model predicts g2 = 0, nonzero values occur in more realistic models of the nucleon which include quark-gluon correlations, finite quark masses, or orbital angular momentum. When scattering from a noninteracting quark, g2(n) can be predicted using next-to-leading order fits to world data for g1(n). Deviations from this prediction provide an opportunity to examine QCD dynamics in nucleon structure. Our results show a positive deviation from this prediction at lower Q2, indicating that contributions such as quark-gluon interactions may be important. Precision data obtained for g1(n) are consistent with next-to-leading order fits to world data.

Recoil polarization for delta excitation in pion electroproduction.

We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W = 1.23 GeV at Q(2) = 1.0 (GeV/c)(2), obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re (S(1+)/M(1+)) = -(6.84 +/- 0.15)% and Re (E(1+)/M(1+)) = -(2.91 +/- 0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and ll(pi) < or = 1 truncation.

Hippocampal contributions to neurocognitive mapping in humans: a new model.

The ability of an organism to develop, maintain, and act upon an abstracted internal representation of spatially extensive environments can provide an increased chance in ensuring that organism's survival. Here, we propose a neurocognitive model of spatial representation describing how several different processes interact and segregate the differing types of information used to produce a unified cognitive map. This model proposes that view-based egocentric and vestibulomotor translational information are functionally and anatomically separate, and that these parallel systems result in independent, but interacting, models within a neurocognitive map of space. In this context, we selectively review relevant portions of the large literature, addressing the establishment and operation of such spatial constructs in humans and the brain systems that underpin them, with particular reference to the hippocampal formation (HF). We present a reinterpretation of the types of knowledge used in the formation of this spatial construct, the processes that act upon this information, the nature of the final spatial representation, and describe how these universal concepts relate to the proposed model of spatial processing. The relevant experimental paradigms used to examine the neural basis of spatial representation and the main findings from previous research are also briefly presented. Finally, we detail a series of testable theoretical, behavioral, and anatomical predictions made by the model.

Dengue virus type 2 in Cuba, 1997: conservation of E gene sequence in isolates obtained at different times during the epidemic.

It was recently reported that disease severity increased during the 1997 Cuban dengue 2 virus epidemic and it was suggested that this might be explained by the appearance of neutralization resistant escape mutants. We investigated these observations and ideas by sequencing 20 dengue 2 virus isolates obtained during the early (low case fatality rate) and the late (high case fatality rate) phases of the outbreak. Our results showed total conservation of the E gene sequence for these isolates suggesting that the selection of envelope gene escape mutants was not the determinant of increased disease severity. Alignment of these sequences with those available in GenBank, followed by Maximum likelihood phylogenetic analysis generated a tree, which indicated that our isolates are closely related to the virus that circulated in Venezuela in 1997/98 and subsequently in Martinique in 1998. This "American/Asian" genotype has therefore gradually dispersed across the Caribbean region during the past 5 years.