Reward and fictive prediction error signals in ventral striatum: asymmetry between factual and counterfactual processing.

Reward prediction error, the difference between the expected and obtained reward, is known to act as a reinforcement learning neural signal. In the current study, we propose a model fitting approach that combines behavioral and neural data to fit computational models of reinforcement learning. Briefly, we penalized subject-specific fitted parameters that moved away too far from the group median, except when that deviation led to an improvement in the model's fit to neural responses. By means of a probabilistic monetary learning task and fMRI, we compared our approach with standard model fitting methods. Q-learning outperformed actor-critic at both behavioral and neural level, although the inclusion of neuroimaging data into model fitting improved the fit of actor-critic models. We observed both action-value and state-value prediction error signals in the striatum, while standard model fitting approaches failed to capture state-value signals. Finally, left ventral striatum correlated with reward prediction error while right ventral striatum with fictive prediction error, suggesting a functional hemispheric asymmetry regarding prediction-error driven learning.

Is glutamate associated with fear extinction and cognitive behavior therapy outcome in OCD? A pilot study.

Cognitive behavioral therapy (CBT) including exposure and response prevention is a well-established treatment for obsessive-compulsive disorder (OCD) and is based on the principles of fear extinction. Fear extinction is linked to structural and functional variability in the ventromedial prefrontal cortex (vmPFC) and has been consistently associated with glutamate neurotransmission. The relationship between vmPFC glutamate and fear extinction and its effects on CBT outcome have not yet been explored in adults with OCD. We assessed glutamate levels in the vmPFC using 3T magnetic resonance spectroscopy, and fear extinction (learning and recall) using skin conductance responses during a 2-day experimental paradigm in OCD patients (n = 17) and in healthy controls (HC; n = 13). Obsessive-compulsive patients (n = 12) then received manualized CBT. Glutamate in the vmPFC was negatively associated with fear extinction recall and positively associated with CBT outcome (with higher glutamate levels predicting a better outcome) in OCD patients. Glutamate levels in the vmPFC in OCD patients were not significantly different from those in HC, and were not associated with OCD severity. Our results suggest that glutamate in the vmPFC is associated with fear extinction recall and CBT outcome in adult OCD patients.

Plasma Aß42/40 Ratio Detects Early Stages of Alzheimer's Disease and Correlates with CSF and Neuroimaging Biomarkers in the AB255 Study.

BACKGROUND: Easily accessible biomarkers are needed for the early identification of individuals at risk of developing Alzheimer's disease (AD) in large population screening strategies. OBJECTIVES: This study evaluated the potential of plasma ß-amyloid (Aß) biomarkers in identifying early stages of AD and predicting cognitive decline over the following two years. DESIGN: Total plasma Aß42/40 ratio (TP42/40) was determined in 83 cognitively normal individuals (CN) and 145 subjects with amnestic mild cognitive impairment (a-MCI) stratified by an FDG-PET AD-risk pattern. RESULTS: Significant lower TP42/40 ratio was found in a-MCI patients compared to CN. Moreover, a-MCIs with a high-risk FDG-PET pattern for AD showed even lower plasma ratio levels. Low TP42/40 at baseline increased the risk of progression to dementia by 70%. Furthermore, TP42/40 was inversely associated with neocortical amyloid deposition (measured with PiB-PET) and was concordant with the AD biomarker profile in cerebrospinal fluid (CSF). CONCLUSIONS: TP42/40 demonstrated value in the identification of individuals suffering a-MCI, in the prediction of progression to dementia, and in the detection of underlying AD pathology revealed by FDG-PET, Amyloid-PET and CSF biomarkers, being, thus, consistently associated with all the well-established indicators of AD.

A direct route to activated two-dimensional cobalt oxide nanosheets for electrochemical energy storage, catalytic and environmental applications.

Two-dimensional Co3O4 nanosheets have emerged as attractive materials for use in a number of relevant technological applications. To exhibit a competitive performance in such uses, however, their structure needs to be activated, which is frequently accomplished via post-synthesis reduction strategies that introduce oxygen vacancies and increase the number of active Co(II) sites. Here, we investigate a direct route for the synthesis of activated Co3O4 nanosheets that avoids reduction post-treatments, yielding materials with a high potential towards energy- and environment-related applications. The synthesis relied on an interim amorphous cobalt oxide material with nanosheet morphology, which upon calcination afforded Co3O4 nanosheets having Co(II) sites in quantities similar to those usually found for Co3O4 nanostructures activated by reduction post-treatments. When tested as electrodes for charge storage, the nanosheets demonstrated a competitive behavior in terms of both capacity and rate capability, e.g., a gravimetric capacity of ∼293 mAh g-1 at 1 A g-1 with 57% retention at 60 A g-1 was measured for nanosheets calcined at 350 °C. The materials were shown to be efficient catalysts for the reduction of nitroarenes (4-nitrophenol and 4-nitroaniline), outperforming other Co3O4 nanostructures, as well as effective adsorbents for the removal of organic dyes (methyl orange, methylene blue) from water.

The behaviour and perception of illness: modulating variables of adherence in patients with haemophilia.

BACKGROUND: The recommended treatment in patients with severe haemophilia is prophylaxis. This prevents bleedings and reduces or delays the haemophilic arthropathy. Adherence defined as the follow-up of the patient to the prescriptions of the health professional to his treatment, both pharmacological and modifications in habits or stylelifes. Adherence rates in haemophilia are better than in other chronic diseases, but there remain reasons for nonadherence. The aim was to see if disease behaviour and disease perception together with coping strategies modulate adherence to treatment. MATERIAL AND METHODS: Multicenter cross-sectional descriptive study. Patients recruited in Units of Hemophilia Hospitals and Regional Haemophilia Associations. Twenty-three patients participated The instruments used are as follows: data sheet, SF-36, A36 Hemophilia-Qol, Illness Perception Questionnaire-Revised (IPQ-R), Illness Behavior Questionnaire (IBQ) and Coping Strategies Inventory (CSI) and VERITAS-Pro. RESULTS: We found that 56% of patients with haemophilia are adherent. The most relevant clinical variables were hemarthrosis, diagnosis of arthropathy and presence of any coinfection, as well as family history, labour status and sociodemographic variables. Age was not a relevant variable in adherence. The worst adherence coincides with poorer quality of life and inadequate coping style. Nonadherent patients show greater conviction of disease, perception of cyclicity, more hypochondriacal behaviour towards the illness and perception concern about possible side effects of medication. CONCLUSION: Adherence in haemophilia requires a more experiential approach and individualized education. It is important that professionals take into account the patient's perception, behaviour and attitude towards the disease to achieve a better adaptation of their coping resources.

Effectiveness of the Medtep Hemophilia online platform for adherence to prophylactic treatment in haemophilia patients: Results from a 1-year observational study.

INTRODUCTION: Medtep Hemophilia platform is an online tool that allows patients with congenital coagulopathies to keep track of their daily condition-related events with the objective of ensuring successful adherence to therapy. AIM: To assess the effectiveness of Medtep Hemophilia in improving adherence to prophylactic treatment in haemophilia A and B patients in a 1-year prospective observational study, as well as its impact on the patient's disease status. METHODS: Patients (>13 years old) received support material to familiarize themselves with Medtep Hemophilia. Adherence to treatment, quality of life (QoL) and illness perception were assessed. Values at baseline, 1, 6 and 12 months, and changes from baseline value were analysed. The Hemophilia Joint Health Score (HJHS) test was applied at baseline and study completion. RESULTS: Forty-six patients were enrolled (43 evaluable). After 1 year, 56.4% patients showed continued use of the platform (100% compliance) whereas 25.6% were inactive. Treatment adherence increased both significantly (P < .001) and progressively during the study. Similarly, improved QoL and illness perception were observed with respect to baseline in most of the questionnaire components (P < .05 after 12 months). A patient's age had no influence on the results, whereas compliant patients (>80% of platform use) tended to score better than noncompliant. The HJHS test values remained similar during the study. CONCLUSION: The Medtep Hemophilia online platform helped the studied patients with haemophilia to improve their adherence to prophylactic treatment, while increasing their QoL and illness perception, as well as joint arthropathies stabilization.

Electrochemical Exfoliation of Graphite in Aqueous Sodium Halide Electrolytes toward Low Oxygen Content Graphene for Energy and Environmental Applications.

Graphene and graphene-based materials have shown great promise in many technological applications, but their large-scale production and processing by simple and cost-effective means still constitute significant issues in the path of their widespread implementation. Here, we investigate a straightforward method for the preparation of a ready-to-use and low oxygen content graphene material that is based on electrochemical (anodic) delamination of graphite in aqueous medium with sodium halides as the electrolyte. Contrary to previous conflicting reports on the ability of halide anions to act as efficient exfoliating electrolytes in electrochemical graphene exfoliation, we show that proper choice of both graphite electrode (e.g., graphite foil) and sodium halide concentration readily leads to the generation of large quantities of single-/few-layer graphene nanosheets possessing a degree of oxidation (O/C ratio down to ∼0.06) lower than that typical of anodically exfoliated graphenes obtained with commonly used electrolytes. The halide anions are thought to play a role in mitigating the oxidation of the graphene lattice during exfoliation, which is also discussed and rationalized. The as-exfoliated graphene materials exhibited a three-dimensional morphology that was suitable for their practical use without the need to resort to any kind of postproduction processing. When tested as dye adsorbents, they outperformed many previously reported graphene-based materials (e.g., they adsorbed ∼920 mg g-1 for methyl orange) and were useful sorbents for oils and nonpolar organic solvents. Supercapacitor cells assembled directly from the as-exfoliated products delivered energy and power density values (up to 15.3 Wh kg-1 and 3220 W kg-1, respectively) competitive with those of many other graphene-based devices but with the additional advantage of extreme simplicity of preparation.

Electrolytic exfoliation of graphite in water with multifunctional electrolytes: en route towards high quality, oxide-free graphene flakes.

Electrolytic--usually referred to as electrochemical--exfoliation of graphite in water under anodic potential holds enormous promise as a simple, green and high-yield method for the mass production of graphene, but currently suffers from several drawbacks that hinder its widespread adoption, one of the most critical being the oxidation and subsequent structural degradation of the carbon lattice that is usually associated with such a production process. To overcome this and other limitations, we introduce and implement the concept of multifunctional electrolytes. The latter are amphiphilic anions (mostly polyaromatic hydrocarbons appended with sulfonate groups) that play different relevant roles as (1) an intercalating electrolyte to trigger exfoliation of graphite into graphene flakes, (2) a dispersant to afford stable aqueous colloidal suspensions of the flakes suitable for further use, (3) a sacrificial agent to prevent graphene oxidation during exfoliation and (4) a linker to promote nanoparticle anchoring on the graphene flakes, yielding functional hybrids. The implementation of this strategy with some selected amphiphiles even furnishes anodically exfoliated graphenes of a quality similar to that of flakes produced by direct, ultrasound- or shear-induced exfoliation of graphite in the liquid phase (i.e., almost oxide- and defect-free). These high quality materials were used for the preparation of catalytically efficient graphene-Pt nanoparticle hybrids, as demonstrated by model reactions (reduction of nitroarenes). The multifunctional performance of these electrolytes is also discussed and rationalized, and a mechanistic picture of their oxidation-preventing ability is proposed. Overall, the present results open the prospect of anodic exfoliation as a competitive method for the production of very high quality graphene flakes.

Investigating the Dispersion Behavior in Solvents, Biocompatibility, and Use as Support for Highly Efficient Metal Catalysts of Exfoliated Graphitic Carbon Nitride.

The liquid-phase exfoliation of graphitic carbon nitride (g-C3N4) to afford colloidal dispersions of two-dimensional flakes constitutes an attractive route to facilitate the processing and implementation of this novel material toward different technological applications, but quantitative knowledge about its dispersibility in solvents is lacking. Here, we investigate the dispersion behavior of exfoliated g-C3N4 in a wide range of solvents and evaluate the obtained results on the basis of solvent surface energy and Hildebrand/Hansen solubility parameters. Estimates of the three Hansen parameters for exfoliated g-C3N4 from the experimentally derived data yielded δD ≈ 17.8 MPa(1/2), δP ≈ 10.8 MPa(1/2), and δH ≈ 15.4 MPa(1/2). The relatively high δH value suggested that, contrary to the case of other two-dimensional materials (e.g., graphene or transition metal dichalcogenides), hydrogen-bonding plays a substantial role in the efficient interaction, and thus dispersibility, of exfoliated g-C3N4 with solvents. Such an outcome was attributed to a high density of primary and/or secondary amines in the material, the presence of which was associated with incomplete condensation of the structure. Furthermore, cell proliferation tests carried out on thin films of exfoliated g-C3N4 using murine fibroblasts suggested that this material is highly biocompatible and noncytotoxic. Finally, the exfoliated g-C3N4 flakes were used as supports in the synthesis of Pd nanoparticles, and the resulting hybrids exhibited an exceptional catalytic activity in the reduction of nitroarenes.

Achieving extremely concentrated aqueous dispersions of graphene flakes and catalytically efficient graphene-metal nanoparticle hybrids with flavin mononucleotide as a high-performance stabilizer.

The stable dispersion of graphene flakes in an aqueous medium is highly desirable for the development of materials based on this two-dimensional carbon structure, but current production protocols that make use of a number of surfactants typically suffer from limitations regarding graphene concentration or the amount of surfactant required to colloidally stabilize the sheets. Here, we demonstrate that an innocuous and readily available derivative of vitamin B2, namely the sodium salt of flavin mononucleotide (FMNS), is a highly efficient dispersant in the preparation of aqueous dispersions of defect-free, few-layer graphene flakes. Most notably, graphene concentrations in water as high as ∼50 mg mL(-1) using low amounts of FMNS (FMNS/graphene mass ratios of about 0.04) could be attained, which facilitated the formation of free-standing graphene films displaying high electrical conductivity (∼52000 S m(-1)) without the need of carrying out thermal annealing or other types of post-treatment. The excellent performance of FMNS as a graphene dispersant could be attributed to the combined effect of strong adsorption on the sheets through the isoalloxazine moiety of the molecule and efficient colloidal stabilization provided by its negatively charged phosphate group. The FMNS-stabilized graphene sheets could be decorated with nanoparticles of several noble metals (Ag, Pd, and Pt), and the resulting hybrids exhibited a high catalytic activity in the reduction of nitroarenes and electroreduction of oxygen. Overall, the present results should expedite the processing and implementation of graphene in, e.g., conductive inks, composites, and hybrid materials with practical utility in a wide range of applications.

Parents of children with haemophilia at an early age: assessment of perceived stress and family functioning.

Haemophilia is a chronic disease that requires a multidisciplinary approach for proper management and control of its clinical manifestations. The perception and management of parents of children with haemophilia can be affected by stressful situations as a result of treatment or disease progression. The aim of this study was to evaluate the perception of stress and family functioning in parents of children with haemophilia 1-7 years. This is an observational clinical study involving 49 parents of children with haemophilia 1-7 years who attended the VIII Workshop for Parents of Children with haemophilia, organized by the Spanish Federation of Hemophilia in La Charca, Murcia (Spain). After obtaining parental consent, the questionnaires was applied to them, FACES III (family functioning) and Pediatric Inventory for Parents (perceived stress), and a record of data on the clinical characteristics and treatment. Significant differences in the perception of stressors by gender of parents were found. A family history of haemophilia, the use of port-a-cath, inhibitor development and gender of the parents were the descriptive variables most correlated with dependents variables. These variables, together with the type of haemophilia affect significantly in the parental stress and family functioning. Parents have difficulty adjusting to disease management, perceiving many stressors. Gender and family history, can hinder the proper compliance with treatments, reducing its effectiveness.

Effectiveness of an educational intervention of physiotherapy in parents of children with haemophilia.

Haemophilia is a haematological disorder with an orthopaedic outcome. It requires not only medical but rather comprehensive care from infancy. The aim of this study was to assess the effectiveness of an educational intervention of Physiotherapy in parents of children with haemophilia under 4 years old. This is a non-randomized clinical trial, in which 22 parents participated children's with haemophilia under 4 years old. Half of them received an educational intervention of Physiotherapy. At the beginning and end of the study, a psychologist blinded to the assignment of subjects to each of the study groups, assessed the perceived quality of life, anxiety, perceived stress and family functioning of parents. A significant improvement was observed in the variables of perceived stress and family functioning of parents in the experimental group. The realization of an educational intervention in parents of children with haemophilia under 4 years old is effective. It reduces the stressors perceived by the parents and improves family cohesion and adaptability, as a consequence of the disease. It is necessary to carry out studies with follow-up periods to assess the effectiveness of educational programs of Physiotherapy for long term.

Prognostic value of changes in resting-state functional connectivity patterns in cognitive recovery after stroke: A 3T fMRI pilot study.

Resting-state studies conducted with stroke patients are scarce. First objective was to explore whether patients with good cognitive recovery showed differences in resting-state functional patterns of brain activity when compared to patients with poor cognitive recovery. Second objective was to determine whether such patterns were correlated with cognitive performance. Third objective was to assess the existence of prognostic factors for cognitive recovery. Eighteen right-handed stroke patients and eighteen healthy controls were included in the study. Stroke patients were divided into two groups according to their cognitive improvement observed at three months after stroke. Probabilistic independent component analysis was used to identify resting-state brain activity patterns. The analysis identified six networks: frontal, fronto-temporal, default mode network, secondary visual, parietal, and basal ganglia. Stroke patients showed significant decrease in brain activity in parietal and basal ganglia networks and a widespread increase in brain activity in the remaining ones when compared with healthy controls. When analyzed separately, patients with poor cognitive recovery (n=10) showed the same pattern as the whole stroke patient group, while patients with good cognitive recovery (n=8) showed increased activity only in the default mode network and fronto-temporal network, and decreased activity in the basal ganglia. We observe negative correlations between basal ganglia network activity and performance in Semantic Fluency test and Part A of the Trail Making Test for patients with poor cognitive recovery. A reverse pattern was observed between frontal network activity and the above mentioned tests for the same group. .

Prognostic significance of blood pressure variability after thrombolysis in acute stroke.

OBJECTIVE: To evaluate the impact of early blood pressure (BP) changes on diffusion-weighted imaging (DWI) lesion evolution and clinical outcome in patients with stroke treated with IV tissue plasminogen activator (tPA). METHODS: We prospectively evaluated 80 patients with stroke with a documented middle cerebral artery occlusion treated with IV tPA. Multiple repeated systolic (SBP) and diastolic (DBP) BP measurements were obtained during 24 hours after admission. All patients underwent DWI, perfusion-weighted imaging, and magnetic resonance angiography before and 36-48 hours after thrombolysis. Recanalization was assessed on transcranial Doppler at 6 hours of stroke onset. NIH Stroke Scale scores were recorded at baseline and 24 hours. Modified Rankin Scale was used to assess 3-month outcome. RESULTS: Recanalization occurred in 44 (55%) patients. BP variability, estimated as the SD of the mean, was associated with DWI lesion growth (r = 0.46, p = 0.0003 for SBP and r = 0.26, p = 0.02 for DBP), early clinical course (p = 0.06 for SBP and p = 0.01 for DBP), and 3-month outcome (p = 0.002 for SBP and 0.07 for DBP). However, the prognostic significance of BP changes differed depending on the presence of recanalization. SBP variability emerged as an independent predictor of DWI lesion growth (beta: 6.9; 95% CI, 3.2 to 10.7, p = 0.003) and worse stroke outcome (OR: 11; 95% CI: 2.2 to 56.1; p = 0.004) in patients without recanalization, but not in recanalized patients. CONCLUSION: Blood pressure variability is associated with greater diffusion-weighted imaging lesion growth and worse clinical course in patients with stroke treated with IV tissue plasminogen activator. However, its impact varies depending on the occurrence of early recanalization after thrombolysis.

[Cocaine and other psychostimulant consumption: their relationship with the childhood hyperactivity syndrome]. / Consumo de cocaína y otros psicoestimulantes: su relación con el síndrome de hiperactividad infantil.

INTRODUCTION: We want to know the attention deficit hyperactivity disorder (ADHD) among those subjects who require treatment due to cocaine and other psychostimulant drugs consumption. No previous Spanish studies have been found. METHODS: Two groups of male subjects were established out of a total of 109 subjects. Their ages ranged from 16 to 40 years. The groups were "experimental" (patients under treatment) and "control", who underwent a urine analysis for toxic agents. An interview elaborated for this and the E mode SCID-I were used. A total of 21 % of the cocaine consumers had a comorbid history of ADHD in childhood versus 3% of the control group. CONCLUSIONS: The data found overlap with the United States studies. ADHD appears as a new risk factor for the posterior development of cocaine abuse disorder, adding a cocaine addict patient subtype that deserves special diagnostic criteria as well as more complete treatment alternatives for these dual diagnosed patients.

Consumo de cocaína y otros psicoestimulantes: su relación con el síndrome de hiperactividad infantil / Cocaine and other psychostimulant consumption: their relationship with the childhood hiperactivity syndrome

Introducción. Se trata de conocer la prevalencia del trastorno por déficit de atención con hiperactividad (ADHD) entre aquellos sujetos que demandan tratamiento por consumo de cocaína y otras drogas psicoestimulantes. No se han encontrado estudios españoles previos. Métodos. Entre un total de 109 pacientes se establecieron dos grupos de sujetos varones y rango entre 16 y 40 años: "experimental" (pacientes en tratamiento) y "control", sometidos a análisis de tóxicos en orina. Se empleó una entrevista elaborada al efecto y el módulo E de la SCID-I. Resultados. El 21 por ciento de los consumidores de cocaína tienen una historia comórbida de ADHD en la infancia frente al 3 por ciento del grupo control. Conclusiones. Los datos hallados se solapan con los estudios estadounidenses. El ADHD aparece como un nuevo factor de riesgo para el posterior desarrollo de un trastorno por abuso de cocaína, añadiendo un subtipo de paciente cocainómano que merece especial rigor en el diagnóstico, así como alternativas de tratamiento más completas para estos pacientes duales (AU)

Análise quantitativa de bissulfito de sódio residual em amostras de camarão colhidas na baixada santista, Estado de São Paulo, Brasil / Quantitative analysis of bissulfito of residual sodium in samples of shrimp reaped in the baixada santista, State of São Paulo, Brasil

A utilização do bissulfito de sódio é permitida e normalizada pelo Serviço de Inspeção Federal, para prevenir a ocorrência das manchas escuras em camarões (black spot). O objetivo deste trabalho foi o de verificar, através da utilização do método químico preconizado por Monier - Williams, as quantidades residuais do referido aditivo, pela análise de trinta amostras, sendo 18 procedentes de barcos pesqueiros e 12 de estabelecimentos varejistas, no período de outubro de 2000 a março de 2001. Embora o Ministério da Agricultura, através do serviço de Inspeção Federal, determine na circular 2031/76 de 22/09/76, que a quantidade residual máxima permitida é de 100 ppm, os resultados obtidos demonstraram que das dezoito amostras colhidas nos barcos, nenhuma atendeu ao referido documento. No caso dos estabelecimentos varejistas apenas 50 por cento estavam dentro do padrão. Se neste estudo for considerado o total das amostras, o percentual em desacordo atinge 80 por cento. Embora a lavagem e a retirada da casca contribuam para diminuir a quantidade do bissulfito, os resultados obtidos no camarão proveniente do varejo indicam que quando são utilizadas quantidades elevadas na origem, os procedimentos habituais não são suficientes, colocando em risco a saúde dos consumidores que podem sofrer reações alérgicas ou mesmo graves intoxicações.

Optical coherence tomography evaluation of the corneal cap and stromal bed features after laser in situ keratomileusis for high myopia and astigmatism.

OBJECTIVE: To study the corneal microstructure by optical coherence tomography (OCT) after laser in situ keratomileusis (LASIK) for high myopia with and without astigmatism. DESIGN: Nonrandomized self-controlled comparative trial. PARTICIPANTS: Sixty-three consecutive LASIK eyes with spherical equivalent refraction between -6.0 and -17.0 diopters (D) and astigmatism between 0.0 and -5.0 D were prospectively recruited for examination. INTERVENTION: LASIK was performed with the Chiron Hansatome microkeratome (160-microm fixed plate) and Summit Apex Plus excimer laser using a 5.5/6.0/6.5-mm multizone pattern. Proper preoperative calculations were performed to ensure stromal beds thicker than 250 microm. MAIN OUTCOME MEASURES: OCT imaging and measurement of corneal thickness was performed preoperatively. In addition, corneal cap and stromal bed thickness measurements were performed 1 day, 1 month, and 3 months postoperatively. RESULTS: The average central corneal pachymetry was 538.9 +/- 26.2 microm preoperatively. Mean corneal cap thickness measured 124.8 +/- 18.5 microm 1-day postoperatively. Mean stromal bed thickness was 295.2 +/- 37.1 microm on the first postoperative day. Compared with the 1-day postoperative examination, the average stromal bed thickness increased significantly by 5.9 microm (P = 0.001) and 7.2 microm (P = 0.001) at the 1-month and 3-month postoperative examinations, respectively. Mean difference between actual (118.7 +/- 27.8 microm) and predicted (104.1 +/- 20.8 microm) central ablation depths was 14.6 +/- 16.7 microm (P = 0.0001). A weak but statistically significant positive association was found between preoperative refraction and the difference between expected and real ablation depth values (R = 0.26; P = 0.042). Posterior stromal beds were more than 250-microm thick in 58 eyes (89.9%) 1 day postoperatively. This safety requirement improved at the 1-month postoperative examination, when the partial regression accounted for slightly thicker stromal beds and only two cases (3.2%) exhibited posterior stromal tissue thinner than 250 microm. These two cases were seen only for corrections exceeding 12 D (P = 0.04). CONCLUSIONS: OCT appears to be a useful tool for the evaluation of both the qualitative and quantitative anatomic outcome of LASIK. Corrections of higher degrees of ametropia run a higher risk of producing a thinner than expected central cornea. Particularly, corrections greater than 12 D may lead eventually to stromal beds thinner than 250 microm, despite proper preoperative calculations. Because corneal flaps are usually thinner than expected with the microkeratome used herein, adequate posterior corneal stroma is preserved in most instances.

[Experimental model of subretinal neovascularization]. / Modelo experimental de neovascularización subretiniana.

PURPOSE: To study the effect of transpupillary photocoagulation with a diode laser in the development of an experimental model of choroidal neovascularization (CNV) in the pigmented rat. METHODS: Diode laser was applied in Long-Evans rats using a setting of 75 microm spot size, 0.05 seconds durations and 200 mW intensity. Follow up was performed by fundus photography and fluorescein angiography that was performed weekly. The animals were sacrificed 7, 14, 21, 30, 45, 52, 60 and 75 days after photocoagulations, the eyes were enucleated and studied by light microscopy. RESULTS: Variation in burn intensity and diameter was common. During the experiment 42 of 93 burns (45%) showed fluorescein staining and late leakage. Neovascularization was confirmed with histopatology in all lesions that showed fluorescein leakage. CONCLUSIONS: Transpupillary diode laser may induce CNV in the pigmented rat. This model may be useful in the in vivo study of choroidal angiogenesis and its therapeutic modulation.

Final clear corneal incision size for AcrySof intraocular lenses.

PURPOSE: To evaluate clear corneal incision size variation in phacoemulsification surgery after the implantation of 2 models of AcrySof intraocular lenses (IOLs). SETTING: Departamento de Oftalmología, Clínica Universitaria de Navarra, Universidad de Navarra, Pamplona, Spain. METHODS: This prospective study comprised 108 eyes that had phacoemulsification and implantation of an Acrysof IOL model MA60BM (56 eyes) or MA30BA (52 eyes). Wound incision size was quantified using the Nordan incision size measurer. The incision size for each IOL model was evaluated before and after implantation and its relationship with the complications during implantation analyzed. RESULTS: Mean incision size varied from 3.7 mm +/- 0.14 (SD) before implantation to 3.9 +/- 0.11 mm after implantation for the MA60BM model (P = .001) and from 3.3 +/- 0.15 mm to 3.4 +/- 0.13 mm for the MA30BA model (P = .001). Intraoperative complications occurred in 14 eyes, and difficulty during IOL implantation, in 23 eyes. There was no association between final incision size and complications. CONCLUSIONS: Incision size increased after the implantation of the 2 AcrySof IOL models used in this study. Modifications to model MA30BA have led to an average decrease in wound size of 0.5 mm with respect to the MA60BM model. Most difficulties encountered were attributable to improper IOL unfolding.