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Respiratory syncytial virus (RSV) is a virus that causes acute respiratory infections in neonates and older adults. To infect host cells, the attachment glycoprotein (G) interacts with a cell surface receptor. This interaction determines the specific cell types that are susceptible to infection. RSV possesses a type I fusion protein F. Type I fusion proteins are metastable when rearrangement of the prefusion F occurs; the fusion peptide is exposed transforming the protein into postfusion form. The transition between the prefusion form and its postfusion form facilitates the viral envelope and the host cell membrane to fuse, enabling the virus to enter the host cell. Understanding the entry mechanism employed by RSV is crucial for developing effective antiviral therapies. In this review, we will discuss the various types of viral fusion proteins and explore the potential entry mechanisms utilized by RSV. A deeper understanding of these mechanisms will provide valuable insights for the development of novel approaches to treat RSV infections.

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Introducción: Las variantes C1236T, G2677T/A y C3435T del gen ABCB1 alteran la función de la glicoproteína P y el transporte de sustancias endógenas y exógenas en la barrera hematoencefálica; además, actúan como factores de susceptibilidad para algunas enfermedades neurodegenerativas.El objetivo del estudio fue determinar la asociación de polimorfismos ABCB1 (C1236T, G2677T/A y C3435T), sus haplotipos y sus combinaciones de genotipos con la enfermedad desmielinizante.MétodoSe genotipificó a 199 pacientes con enfermedad desmielinizante y a 200 controles mestizos mexicanos mediante PCR-RFLP y secuenciación Sanger para comparar las frecuencias de alelos, genotipos, haplotipos y combinaciones de genotipos entre pacientes y controles. El análisis estadístico se realizó con regresión logística y χ2 de Pearson al 95% de confianza; se calculó la OR y se evaluó la asociación con enfermedad desmielinizante.ResultadosLos haplotipos TTT y CGC fueron los más frecuentes en pacientes y controles. El alelo G2677 (OR = 1,79; IC 95%: 1,12-2,86; p = 0,015) muestra asociación con enfermedad desmielinizante, así como los genotipos GG2677 (OR = 2,72; IC 95% = 1,11-6,68; p = 0,025) y CC3435 (OR = 1,82; IC 95%: 1,15-2,90; p = 0,010) y su combinación GG2677/CC3435 (OR = 2,02; IC 95%: 1,17-3,48; p = 0,010) y el haplotipo CAT (OR = 0,21; IC 95%: 0,05-0,66; p = 0,001).Los portadores TTTTTT presentaron la edad de inicio más temprana (23,0 ± 7,7 vs. 31,6 ± 10,7; p = 0,0001).ConclusionesLa combinación de genotipos GG2677/CC3435 está asociada al desarrollo de enfermedad desmielinizante en esta muestra, principalmente en el sexo masculino, en el cual puede darse acumulación tóxica de sustratos de glicoproteína P.En este estudio, la edad de inicio de la enfermedad desmielinizante podría ser modulada diferencialmente entre sexos por el alelo G2677 del gen ABCB1. (AU)

Introduction: The C1236T, G2677T/A, and C3435T variants of the ABCB1 gene alter the functioning of P-glycoprotein and the transport of endogenous and exogenous substances across the blood-brain barrier, and act as risk factors for some neurodegenerative diseases.This study aimed to determine the association between demyelinating disease and the C1236T, G2677T/A, and C3435T variants of ABCB1 and its haplotypes and combinations of genotypes.MethodsPolymerase chain reaction with restriction fragment length polymorphism analysis (PCR-RFLP) and Sanger sequencing were used to genotype 199 patients with demyelinating disease and 200 controls, all Mexicans of mixed race; frequencies of alleles, genotypes, haplotypes, and genotype combinations were compared between patients and controls. We conducted a logistic regression analysis and calculated chi-square values and 95% confidence intervals (CI); odds ratios (OR) were calculated to evaluate the association with demyelinating disease.ResultsThe TTT and CGC haplotypes were most frequent in both patients and controls. The G2677 allele was associated with demyelinating disease (OR: 1.79; 95% CI: 1.12-2.86; P = .015), as were the genotypes GG2677 (OR: 2.72; 95% CI: 1.11-6.68; P = .025) and CC3435 (OR: 1.82; 95% CI: 1.15-2.90; P = .010), the combination GG2677/CC3435 (OR: 2.02; 95% CI, 1.17-3.48; P = .010), and the CAT haplotype (OR: 0.21; 95% CI: 0.05-0.66; P = .001).TTTTTT carriers presented the earliest age of onset (23.0 ± 7.7 years, vs. 31.6 ± 10.7; P = .0001).ConclusionsThe GG2677/CC3435 genotype combination is associated with demyelinating disease in this sample, particularly among men, who may present toxic accumulation of P-glycoprotein substrates.In our study, the G2677 allele of ABCB1 may differentially modulate age of onset of demyelinating disease in men and women. (AU)

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INTRODUCTION: The C1236T, G2677T/A, and C3435T variants of the ABCB1 gene alter the functioning of P-glycoprotein and the transport of endogenous and exogenous substances across the blood-brain barrier, and act as risk factors for some neurodegenerative diseases. This study aimed to determine the association between demyelinating disease and the C1236T, G2677T/A, and C3435T variants of ABCB1 and its haplotypes and combinations of genotypes. METHODS: Polymerase chain reaction with restriction fragment length polymorphism analysis (PCR-RFLP) and Sanger sequencing were used to genotype 199 patients with demyelinating disease and 200 controls, all Mexicans of mixed race; frequencies of alleles, genotypes, haplotypes, and genotype combinations were compared between patients and controls. We conducted a logistic regression analysis and calculated chi-square values and 95% confidence intervals (CI); odds ratios (OR) were calculated to evaluate the association with demyelinating disease. RESULTS: The TTT and CGC haplotypes were most frequent in both patients and controls. The G2677 allele was associated with demyelinating disease (OR: 1.79; 95% CI, 1.12-2.86; P =  .015), as were the genotypes GG2677 (OR: 2.72; 95% CI, 1.11-6.68; P =  .025) and CC3435 (OR: 1.82; 95% CI, 1.15-2.90; P =  .010), the combination GG2677/CC3435 (OR: 2.02; 95% CI, 1.17-3.48; P =  .010), and the CAT haplotype (OR: 0.21; 95% CI, 0.05-0.66; P =  .001). TTTTTT carriers presented the earliest age of onset (23.0 ±â€¯7.7 years, vs 31.6 ±â€¯10.7; P =  .0001). CONCLUSIONS: The GG2677/CC3435 genotype combination is associated with demyelinating disease in this sample, particularly among men, who may present toxic accumulation of P-glycoprotein substrates. In our study, the G2677 allele of ABCB1 may differentially modulate age of onset of demyelinating disease in men and women.

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BACKGROUND: Multiple Sclerosis is the central nervous system's most common demyelinating disease and the second leading cause of neurological disability in young adults. Its natural development involves physical and cognitive impairment. Patients commonly perceive discrimination against them, regardless of its occurrence, accepting it as an inherent part of the disease. OBJECTIVE: This study aimed to determine the association between perceived discrimination and the depressive symptoms and physical disability present in patients diagnosed with multiple sclerosis, treated at the Demyelinating Diseases Clinic of the National Institute of Neurology and Neurosurgery, Manuel Velasco Suárez. METHODS: A cross-sectional study was conducted in 98 patients diagnosed with multiple sclerosis. Demographic and clinical variables were obtained through clinical interviews. The severity of the disease was determined using the Extended Disability Status Scale (EDSS), depressive symptoms were assessed with the Beck Depression Inventory (BDI), and perceived discrimination was rated using the King Internalized Stigma Scale. RESULTS: The studied sample's mean age was 36.3 years, schooling 13.6 years, symptoms onset was at 26.2 years (with a delay in diagnosis of 3.2 years), and a disease evolution of 10.9 years. 71.4% were single; 52% had an unpaid work activity and 57.1% were women. The EDSS average was 3.5 points; 24.5% presented moderate to severe depressive symptoms and 53.1% referred perceived discrimination. CONCLUSIONS: Perceived discrimination in patients with multiple sclerosis was associated with earlier disease onset, depressive symptoms, and the lack of caregivers. Medical care and life quality improvement for this vulnerable group require greater education regarding the disease and the establishment of patient support programs.

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INTRODUCTION: The C1236T, G2677T/A, and C3435T variants of the ABCB1 gene alter the functioning of P-glycoprotein and the transport of endogenous and exogenous substances across the blood-brain barrier, and act as risk factors for some neurodegenerative diseases. This study aimed to determine the association between demyelinating disease and the C1236T, G2677T/A, and C3435T variants of ABCB1 and its haplotypes and combinations of genotypes. METHODS: Polymerase chain reaction with restriction fragment length polymorphism analysis (PCR-RFLP) and Sanger sequencing were used to genotype 199 patients with demyelinating disease and 200 controls, all Mexicans of mixed race; frequencies of alleles, genotypes, haplotypes, and genotype combinations were compared between patients and controls. We conducted a logistic regression analysis and calculated chi-square values and 95% confidence intervals (CI); odds ratios (OR) were calculated to evaluate the association with demyelinating disease. RESULTS: The TTT and CGC haplotypes were most frequent in both patients and controls. The G2677 allele was associated with demyelinating disease (OR: 1.79; 95% CI: 1.12-2.86; P=.015), as were the genotypes GG2677 (OR: 2.72; 95% CI: 1.11-6.68; P=.025) and CC3435 (OR: 1.82; 95% CI: 1.15-2.90; P=.010), the combination GG2677/CC3435 (OR: 2.02; 95% CI, 1.17-3.48; P=.010), and the CAT haplotype (OR: 0.21; 95% CI: 0.05-0.66; P=.001). TTTTTT carriers presented the earliest age of onset (23.0±7.7 years, vs. 31.6±10.7; P=.0001). CONCLUSIONS: The GG2677/CC3435 genotype combination is associated with demyelinating disease in this sample, particularly among men, who may present toxic accumulation of P-glycoprotein substrates. In our study, the G2677 allele of ABCB1 may differentially modulate age of onset of demyelinating disease in men and women.

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OBJECTIVE: The aim of this work was to evaluate the quality of life of patients with multiple sclerosis and its association with depressive symptoms and physical health. METHOD: A total of 117 patients clinically diagnosed with Multiple Sclerosis (MS) were studied. The MSQOL-54 scale was applied. The depressive symptoms were assessed using the Beck Depression Inventory (BDI), while degree of physical disability was evaluated with the EDSS (Expanded Disability Status Scale). The results of these last two instruments were associated with MSQOL-54 to determine its influence on the perception of quality of life. RESULTS: We evaluated 65 women (56%) and 52 men (44%), with a mean age of 35 years, a mean age of 27 years at the time of diagnosis, and a mean evolution of 8 years. 88% of the patients showed the relapsing-remitting subtype; 42% had paid employment; 29% of the studied patients required help to perform daily activities; 75% took disease-modifying medications. They obtained on average a score of 3.62 ±â€¯2.30 on the EDSS and 11.5 ±â€¯9.21 on the BDI. The general average in MSQOL-54 was 64.67 ±â€¯17.52. CONCLUSIONS: Quality of life, in patients with multiple sclerosis is an issue that worries health personnel, it is essential to implement strategies for reducing the impact of the disease on patients' lives, mainly through the application of programs aimed to decrees depression and improve social support.

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PURPOSE: Eslicarbazepine-acetate (ESL) is a third generation antiepileptic drug licensed as adjunctive therapy in adults with focal seizures. Efficacy and safety of ESL have been established in real-life setting. However, data about outcomes in elderly patients are scarce. Primary endpoint was to evaluate outcomes of ESL in elderly patients. METHOD: This was a retrospective survey that included patients >65years with focal seizures who started ESL between January 2010 and July 2012 at 12 Spanish Hospitals. ESL was prescribed individually according to real-life practice. Efficacy and safety were evaluated over 1year. These patients were included within the bigger study ESLIBASE. RESULTS: We included 29 patients, most of them males (18). Mean age was 71.2 year-old and epilepsy evolution was 20 years. Eighteen were pharmacorresistant at baseline. At 12 months, the mean dose was 850mg/day, the retention rate 69%, the responder rate 62% and 24.1% were seizure-free. At 12 months, 16 patients (55.2%) had ≥1 adverse effect (AE), that led to discontinuation in 7 patients. Dizziness, nausea and ataxia were the most common AEs. The tolerability profile improved in 4/5 patients who switched from carbamazepine (CBZ) or oxcarbazepine (OXC) to ESL due to AEs. CONCLUSIONS: ESL was well-tolerated and effective in elderly patients in a real-life setting over 1year, with a dose around 800mg/day. AE effects improved in most of who switched from CBZ or OXC to ESL.

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PURPOSE: Evaluate real-life experience with eslicarbazepine acetate (ESL) after first monotherapy failure in a large series of patients with focal epilepsy. METHOD: Multicentre, retrospective, 1-year, observational study in patients older than 18 years, with focal epilepsy, who had failed first antiepileptic drug monotherapy and who received ESL. Data from clinical records were analysed at baseline, 3, 6 and 12 months to assess effectiveness and tolerability. RESULTS: Eslicarbazepine acetate was initiated in 253 patients. The 1-year retention rate was 92.9%, and the final median dose of ESL was 800 mg. At 12 months, 62.3% of patients had been seizure free for 6 months; 37.3% had been seizure free for 1 year. During follow-up, 31.6% of the patients reported ESL-related adverse events (AEs), most commonly somnolence (8.7%) and dizziness (5.1%), and 3.6% discontinued due to AEs. Hyponatraemia was observed in seven patients (2.8%). After starting ESL, 137 patients (54.2%) withdrew the prior monotherapy and converted to ESL monotherapy; 75.9% were seizure free, 87.6% were responders, 4.4% worsened, and 23.4% reported ESL-related AEs. CONCLUSION: Use of ESL after first monotherapy failure was associated with an optimal seizure control and tolerability profile. Over half of patients were converted to ESL monotherapy during follow-up.

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BACKGROUND: Real-world data of current antiepileptic drugs (AEDs) used to treat focal seizures is of importance to understand the efficacy and safety outside of the clinical trial setting. Here we report real-world data from a large series of patients treated with perampanel for 1year. METHODS: FYDATA was a multicentre, retrospective, 1-year observational study assessing the efficacy and safety of adjuvant perampanel in patients ≥12 years of age with focal epilepsy in a real-world setting. At 12 months, the proportion of patients who were seizure free, median percentage seizure reduction, proportion of responders, retention rate and proportion of patients with adverse events (AEs) were assessed. Analyses were also performed to identify any patient-, medication- and disease-related factors associated with a large clinical response or carry a risk for AEs. RESULTS: A total of 464 patients were included in the study with a retention rate of 60.6% at 1year. The mean number of prior AEDs was 7.8. The median percentage reduction in overall seizures was 33.3% (75% for secondary generalised seizures) after 1year, with 7.2% of patients achieving seizure freedom. Furthermore, patients on non-enzyme-inducing AEDs were more likely to achieve seizure freedom, and logistic regression revealed that patients aged ≥65 years, those with epilepsy due to a vascular aetiology and those who had received fewer prior AEDs showed a better clinical response to perampanel. A total of 62.9% of the patients experienced AEs at 12 months; dizziness, somnolence and irritability were the most frequent AEs. Patients with prior psychiatric comorbidities (hyperactivity and personality disorder) were more likely to experience psychiatric AEs with perampanel, and slower titration schedules were associated with less AEs overall. CONCLUSION: Perampanel, for the treatment of focal epilepsy in a real-world setting in a refractory population, over 1year, demonstrates a similar efficacy and safety profile to that observed in clinical trials. Our results have implications for the optimisation of perampanel use in a clinical setting.

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RATIONALE: There is a lack of knowledge regarding the epidemiology, clinical characterization, and survival in pediatric pulmonary hypertension. OBJECTIVES: To describe the epidemiology, outcomes, and risk factors for mortality in pediatric pulmonary hypertension in Spain. METHODS: We analyzed data from the Spanish Registry for Pediatric Pulmonary Hypertension. From January 2009 to June 2012, a total of 225 patients diagnosed with pulmonary hypertension in 1998 or after were collected from 21 referral and nonreferral centers. We included all Nice etiologies, estimated incidence and prevalence of pulmonary hypertension in the Spanish pediatric population, and analyzed risk factors for mortality (Nice etiologic group, clinical and hemodynamic variables). Patients were classified as follows: group I, pulmonary arterial hypertension (n = 142; 61%); group II, left heart disease (n = 31; 14%); group III, respiratory disease (n = 41; 18%); group IV, thromboembolic pulmonary hypertension (n = 2; 1%); or group V, mostly inherited metabolic diseases (n = 10; 4.5%). Of the patients studied, 31% had multifactorial pulmonary hypertension. MEASUREMENTS AND MAIN RESULTS: Mean age at diagnosis was 4.3 ± 4.9 years (50% < 2 yr). Survival rates at 1 and 3 years were 80 and 74% for the whole cohort, and 89 and 85% for patients with pulmonary arterial hypertension. Independent risk factors for mortality included an etiologic group other than pulmonary arterial hypertension (P < 0.001), age at diagnosis younger than 2 years old (P < 0.001), advanced functional class at diagnosis (P < 0.001), and high right atrial pressure at diagnosis (P = 0.002). CONCLUSIONS: In moderate to severe pediatric pulmonary hypertension, the prognosis is better in pulmonary arterial hypertension than in other Nice categories. In pediatric pulmonary hypertension age at diagnosis younger than 2 years is a risk factor for mortality, in addition to the previously established risk factors.

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BACKGROUND: Eslicarbazepine acetate (ESL) is a new antiepileptic drug (AED) licensed as adjunctive therapy in adults with partial-onset or focal seizures. OBJECTIVE: To evaluate in a clinical practice setting the long-term efficacy and safety of ESL in patients with focal seizures. METHODS: ESLIBASE was a retrospective study that included all patients with focal seizures who started ESL between January 2010 and July 2012 at 12 hospitals. ESL was prescribed individually according to real-life practice. Efficacy and safety were evaluated over 1 year. Switching from carbamazepine (CBZ) and oxcarbazepine (OXC) was assessed. RESULTS: Three hundred and twenty-seven patients were included; 78% of patients were taking ≥2 other AEDs at baseline. Most (87%) began ESL because of poor seizure control and 13% because of adverse events (AEs) with CBZ or OXC. After 1 year, 237 patients (72.4%) remained on ESL. At 3, 6 and 12 months, the responder rate was 46.3%, 57.9%, and 52.5%, and 21.0%, 28.0%, and 25.3% of patients were seizure free. The responder rate significantly increased when ESL was combined with a non-sodium channel-targeting drug (non-SC drug) (66.7%) versus an SC drug (47.7%; p<0.001). At 12 months, 40.7% of patients had ≥1 AE; AEs led to treatment discontinuation in 16.2%. Dizziness, nausea, and somnolence were the most common AEs. The tolerability profile improved in >50% of the patients who switched from CBZ or OXC to ESL because of AEs. CONCLUSIONS: ESL was well tolerated and effective in a real-world setting over 1 year. Side-effect profile improved when OXC and CBZ recipients were switched to ESL.

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AIM: Different patients exhibit wide variability in the way they respond to medications. Individual differences in drug response can result from environmental factors, as well as genetic determinants. In particular, inherited differences in the metabolism and disposition of drugs can have a great influence on the efficacy and toxicity of medications, so herein we focus on the pharmacogenetics of drug metabolism. DEVELOPMENT: Clinical observations of inherited differences in drug effects were first documented in the 1950s, giving rise to the field of pharmacogenetics. These observations were then followed by population studies of drug disposition phenotype, then biochemical, and eventually molecular elucidation of the genetic defect associated with the inherited trait. Genetic polymorphisms have been described for many phase I and phase II drug-metabolizing enzymes including several cytochromes P450, N-acetyltransferases, and thiopurine S-methyltransferase. Rapid advances in human genomics gave birth to pharmacogenomics, an emerging discipline that uses genome-wide approaches to study the entire spectrum of genes involved in drug response. High-through-put genomic technologies will serve as the foundation of personalized therapies. CONCLUSIONS: Knowledge of an individual's genetic variability in drug response may be clinically and economically important and could provide the basis for a rational approach to drug prescription in neuropsychiatric disorders.

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Antecedentes y objetivo: Un stent es un dispositivo útil en el tratamiento de lesiones estenóticas vasculares asociadas a cardiopatías congénitas. En el año 1997 iniciamos nuestra experiencia, cuyos resultados se exponen en este trabajo. Pacientes y método: Se han implantado 17 stents, en 12 niños con edad media de 82 meses (2-168 meses) mediante 13 procedimientos. Ocho pacientes tenían estenosis de ramas pulmonares posquirúrgicas; 3 pacientes recoartaciones de aorta y uno, cardiopatía compleja dependiente del ductus. En los primeros 8 pacientes se efectuó cateterismo derecho y se siguió la técnica habitual de implantación con guía de alto soporte y vaina de Mullins. En los restantes el abordaje fue por vía arterial femoral. Se utilizaron 13 stents de Palmaz; 3 stents Express; y uno, Intrastent. Resultados: El diámetro de las lesiones se incrementó tras el implante desde 3,1 (2,8-5,6) hasta 12 (10-15) mm (p<=0,002), y el gradiente a través de las estenosis descendió desde 32 (21-45) a 8,5 (0-11,5) mmHg (p<=0,002). En el paciente dependiente del ductus permitió la suspensión de prostaglandinas y el alta hospitalaria. Tras un seguimiento medio de 27 meses (1-60) ha habido una oclusión completa tardía de rama pulmonar y una parcial de arteria lobular superior derecha. Un enfermo falleció por causas ajenas al stent (shock cardiogénico previo), el resto están asintomáticos y no precisan medicación. Conclusión: El stent es un dispositivo seguro y eficaz. Puede ser utilizado en una amplia variedad de lesiones estenóticas (AU)

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BACKGROUND AND AIM: Balloon-expandable stents are useful in treating vascular stenotic lesions associated with congenital heart defects. We report our experience of this device since 1997. PATIENTS AND METHOD: Seventeen stents were implanted in 12 children in 13 procedures. The mean age of the patients was 82 months (range: 2-168 months). Eight patients had postsurgical stenoses in branch pulmonary arteries, three patients had aortic re-coarctation and one patient had a ductus-dependent complex heart defect. In the first eight patients we performed right catheterization, following the usual technique of percutaneous implantation with super-stiff wire and Mullins sheath. In the remaining patients, vascular access was through the femoral artery. The Palmaz stent was used in 13 patients, Express stents in three and Intrastent in one patient. RESULTS: After stent implantation, the diameter of the narrowings increased from 3.1 mm (2.8-5.6) to 12 mm (10-15) (p < 0.002) and the gradient was reduced from 32 mmHg (21-45) to 8.5 mmHg (0-11.5) (p < 0.002). In the patient with ductus-dependent heart defect, the procedure allowed prostaglandin E1 withdrawal and hospital discharge. After a mean follow-up of 27 months (range: 1-60 months) one occurrence of late complete occlusion of branch pulmonary artery and one case of side-branch partial occlusion (right superior lobe branch) have been detected. One patient died from causes unrelated to the stent (prior cardiogenic shock). The remaining patients are asymptomatic and medication free. CONCLUSION: The stent is a safe and effective device that could be used in a wide variety of stenotic vascular lesions.

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We examined rhabdom structure and the distribution of filamentous actin in the photoreceptor outer segments of the retina of Octopus bimaculoides. Animals were dark- or light-adapted, fixed, embedded and sectioned for light and electron microscopy. Statistical analyses were used to compare relative cross-sectional areas of rhabdom microvilli and core cytoplasm within and between the two lighting conditions. Dark-/light-adapted rhabdoms were also prepared for confocal laser scanning microscopy and labeled with fluorescence-tagged phalloidin. Results show differences in the morphology of dark- and light-adapted octopus rhabdoms with the cross-sectional areas of the rhabdoms increasing in dark-adapted retinas and diminishing in the light. Comparisons between the lighting conditions show that an avillar portion of the photoreceptor outer segment membrane, prominent in the light-adapted retina, is recruited to form new rhabdomere microvilli in dark-adapted eyes. Filamentous actin was associated with the avillar membrane in light-adapted retinas, which may indicate that actin and other microvillus core proteins remain linked to the avillar membrane to support rapid microvillus formation in the dark. Photopigment redistributions also occur in light- and dark-adapted retinas, and this study suggests that these changes must be coordinated with the simultaneous breakdown and reformation of the rhabdomere microvilli.

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In cephalopods, the complex rhodopsin-retinochrome system serves to regenerate metarhodopsin and metaretinochrome after illumination. In the dark, a soluble protein, retinal-binding protein (RALBP), shuttles 11-cis retinal released from metaretinochrome located in the photoreceptor inner segments to metarhodopsin present in the rhabdoms. While in the rhabdoms, RALBP delivers 11-cis retinal to regenerate rhodopsin and in turn binds the all-trans isomer released by metarhodopsin. RALBP then returns all-trans retinal to the inner segments to restore retinochrome. The conventional interpretation of retinoid cycling is contradicted by immunocytochemical studies showing that, in addition to rhodopsin, retinochrome is present in the rhabdomal compartment, making possible the direct exchange of chromophores between the metapigments with the potential exclusion of RALBP. By using immunofluorescence and laser scanning confocal microscopy, we have precisely located opsin, aporetinochrome, and RALBP in light-/dark-adapted octopus retinas. We found differences in the distribution of all three proteins throughout the retina. Most significantly, comparison of cross sections though light- and dark-adapted rhabdoms showed a dramatic shift in position of the proteins. In the dark, opsin and retinochrome colocalized at the base of the rhabdomal microvilli. In the light, opsin redistributed along the length of the microvillar membranes, and retinochrome retreated to a location that is perhaps extracellular. RALBP was present in the core cytoplasm of the photoreceptor outer segments in the dark, and RALBP moved to the periphery in the light. Because of the colocalization of opsin and retinochrome in the dark, we believe that the two metapigments participate directly in chromophore exchange. RALBP may serve to transport additional chromophore from the inner segments to the rhabdoms and may not be immediately involved in the exchange process.

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INTRODUCTION: We analysed the usefulness of Doppler echocardiography to determine the presence and severity of pulmonary hypertension (PH) in children. METHOD: The whole group consisted of 63 patients, 42 with congenital heart disease that underwent cardiac catheterization (32 of whom had PH = study group) and 21 healthy children. These 21 patients and the remaining 10 without PH at cardiac catheterization made up the control group. All children were studied with Doppler Echocardiography to evaluate the pulmonary flow pattern with the sample volume placed in the pulmonary artery trunk, 1 cm distal to the pulmonic valve. The preejection period (PEP), ejection period (EP), acceleration time (AcT), the indexes PEP/EP, PEP/AcT, AcT/EP and the morphologic pattern of the pulmonary flow (type I: with peak flow velocity at midsystole; type II: with peak flow velocity in early systole; type III: with midsystolic notching) were analysed and quantitative parameters corrected according to hear rate by dividing theirs value by the square root of R-R interval. In the hemodynamic study we analysed the systolic (SPAP), diastolic and mean pulmonary artery pressure, and the mean pulmonary pressure/mean systemic pressure ratio (Pp/Sp). We compared the echocardiographic variables in both, study and control groups, and analysed the hemodynamic and echocardiographic correlation between the variables in question. RESULTS: Pattern I of pulmonary flow was associated with absence of PH and pattern II and III with PH (p < 0.001). The best results of quantitative variables were either corrected AcT (AccT) rather less in the study group than in control group (2.89 +/- 0.56 vs 4.05 +/- 0.56 ms, p < 0.001) and PPE/AcT index, 1.28 +/- 0.3 in the hypertensive group and 0.78 +/- 0.16 in the control group (p < 0.001). The best correlation were AcT with SPAP (r = -0.82) and Act with Pp/Sp ratio (r = -0.84). CONCLUSIONS: We consider that pulmonary flow analysed with Doppler echocardiography is a reliable, suitable and non-invasive method to evaluate PH in children.

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INTRODUCTION: The optimal management of infants with tetralogy of Fallot continues to evolve. We review our series to evaluate the results. PATIENTS AND METHODS: From 1979 to 1992, 101 children with tetralogy of Fallot without pulmonary atresia, were operated on. Infundibular and valvar stenosis were present in 59 cases (58.4%), distal stenosis in 24 (23.7%) and trunk and/or branches hypoplasia in 14 (13.9%). Until 1985, symptomatic infants underwent palliative surgical techniques. Since then, we prefer early repair as elective treatment in all cases, using palliative techniques only in symptomatic infants with inadequate anatomy. Palliative techniques were used in 35 children (34.6%), mean age at surgery was 6.7 +/- 6.7 months; corrective surgery, after palliative technique, in 23 children (22.8%), mean age at surgery was 36.0 +/- 12.9 months and primary correction in 66 children (65.3%), mean age at surgery was 30.7 +/- 20.8 months. For 45 patients (44.6%) the right ventricular outflow tract obstruction was relieved by a transannular patch. RESULTS: Post-repair right ventricular-left ventricular pressure ratio is a usefull index to predict the short and long-term evolution of this cardiopathy. Thus, values were significantly smaller in children without postoperative cardiac failure (0.51 +/- 0.10 vs 0.59 +/- 0.15; p < 0.01), in the survivors (0.53 +/- 0.12 vs 0.72 +/- 0.13; p < 0.001) and in those with better functional status in the follow-up (0.52 +/- 0.12 vs 0.66 +/- 0.13; p < 0.001). Whole mortality was 13% for two-stage correction and 7.6% for primary correction. From 1985 mortality has reduced at 6.7 and 2.3% respectively. The follow-up was completed in 78 children with corrective surgery (96%), with a mean of 43.4 +/- 32.6 months. There were three later deaths. Actuarial survival at six years is 86%. CONCLUSION: We have proved that the optimal treatment in infants with tetralogy of Fallot and suitable size pulmonary vascular tree is the early primary repair. The pressure relation between both ventricles post-repair is a useful index for the outcome.

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