Latent inhibition as a Model of Schizophrenia: from Learning to Psychopathology

In schizophrenia, attentional processes may be altered and become the basis of another symptomatology such as delirium and hallucinations. One of the experimental approaches to the study of attentional processes employs the phenomenon of latent inhibition. Behaviourally, latent inhibition is expressed as a delay or difficulty in learning the relationship between stimuli due to prior experience of the subject with one of the inconsequential stimuli. This learning phenomenon fulfils an adaptive function that enables the organism to release attention from irrelevant stimuli. Schizophrenics do not show this latent inhibition effect due to attentional alterations, that is, they have selective attention difficulties. Clinical data coincide with results obtained from both animals and normal subjects and with data from psychopharmacological studies. Most of the studies show that the dopaminergic system plays an important role in latent inhibition and therefore would support the dopaminergic hypothesis of schizophrenia. Furthermore, latent inhibition is used as a model to evaluate the mechanisms of antipsychotic drug action, as well as for the study of the aetiology of schizophrenia. Finally, latent inhibition opens a line of research in cognitive inhibition processes in schizotypy and the possibility of studying other psychopathological disorders. The model proposed is based on experimental, neurochemical and clinical premises that make it a promising topic of future for research

Reduced Prepulse Inhibition as a Biomarker of Schizophrenia

The startle response is composed by a set of reflex behaviors intended to prepare the organism to face a potentially relevant stimulus. This response can be modulated by several factors as, for example, repeated presentations of the stimulus (startle habituation), or by previous presentation of a weak stimulus (Prepulse Inhibition [PPI]). Both phenomena appear disrupted in schizophrenia that is thought to reflect an alteration in dopaminergic and glutamatergic neurotransmission. In this paper we analyze whether the reported deficits are indicating a transient effect restricted to the acute phase of the disease, or if it reflects a more general biomarker or endophenotype of the disorder. To this end, we measured startle responses in the same set of thirteen schizophrenia patients with a cross-sectional design at two periods: 5 days after hospital admission and 3 months after discharge. The results showed that both startle habituation and PPI were impaired in the schizophrenia patients at the acute stage as compared to a control group composed by 13 healthy participants, and that PPI but not startle habituation remained disrupted when registered 3 months after the discharge. These data point to the consideration of PPI, but not startle habituation, as a schizophrenia biomarker.Ministerio de Economia y Competitividad PSI2012-32077Ministerio de Economia y Competitividad PSI2015-64965-P/MINECO-FEDER, UEInstituto de Salud Carlos III PI11/0233

Nutrición parenteral domiciliaria en España 2018. Informe del Grupo de Nutrición Artificial Domiciliaria y Ambulatoria NADYA

Objetivo: comunicar los datos de nutrición parenteral domiciliaria (NPD) obtenidos del registro del grupo NADYA-SENPE (www.nadya-senpe.com) del año 2018. Material y métodos: análisis descriptivo de los datos recogidos de pacientes adultos y pediátricos con NPD en el registro NADYA-SENPE del 1 de enero al 31 de diciembre de 2018. Resultados: se registraron 278 pacientes (54, 7% mujeres), 23 niños y 255 adultos, procedentes de 45 hospitales españoles, lo que representa una tasa de prevalencia de 5, 95 pacientes/millón de habitantes/año 2018. El diagnóstico más frecuente en adultos fue “oncológico paliativo” (22, 0%), seguido de “otros”. En niños fue la enfermedad de Hirschsprung junto con la enterocolitis necrotizante, con cuatro casos (17, 4%). El primer motivo de indicación fue síndrome de intestino corto tanto en niños (60, 9%) como en adultos (35, 7%). El tipo de catéter más utilizado fue el tunelizado tanto en niños (81, 0%) como en adultos (41, 1%). Finalizaron 75 episodios, la causa más frecuente fue el fallecimiento (52, 0%) y el paso a vía oral (33, 3%). Conclusiones: el número de centros y profesionales colaboradores en el registro de pacientes que reciben NPD se mantiene estable, así como las principales indicaciones y los motivos de finalización de la NPD. Aim: To communicate home parenteral nutrition (HPN) data obtained from the HPN registry of the NADYA-SENPE group (www.nadya-senpe.  com) for the year 2018. Material and methods: Descriptive analysis of the data collected from adult and pediatric patients with HPN in the NADYA-SENPE group registry from January 1st, 2018 to December 31st, 2018.  Results: There were 278 patients from 45 Spanish hospitals (54.7% women), 23 children and 255 adults, which represent a prevalence rate of 5.95 patients/million inhabitants/year 2018. The most frequent diagnosis in adults was “palliative cancer” (22.0%), followed by “others”. In children it was Hirschsprung’s disease together with necrotizing enterocolitis, with four cases (17.4%). The first indication was short bowel syndrome in both children (60.9%) and adults (35.7%). The most frequently used type of catheter was tunneled in both children (81.0%) and adults (41.1%). Ending 75 episodes, the most frequent cause was death (52.0%) and change to oral feeding (33.3%). Conclusions: The number of centers and collaborating professionals in the registry of patients receiving HPN remains stable, as well as the main indications and reasons for termination of HPN

Parkinsonism and spastic paraplegia type 7: Expanding the spectrum of mitochondrial Parkinsonism

Background Pathogenic variants in the spastic paraplegia type 7 gene cause a complicated hereditary spastic paraplegia phenotype associated with classical features of mitochondrial diseases, including ataxia, progressive external ophthalmoplegia, and deletions of mitochondrial DNA. Objectives To better characterize spastic paraplegia type 7 disease with a clinical, genetic, and functional analysis of a Spanish cohort of spastic paraplegia type 7 patients. Methods Genetic analysis was performed in patients suspecting hereditary spastic paraplegia and in 1 patient with parkinsonism and Pisa syndrome, through next‐generation sequencing, whole‐exome sequencing, targeted Sanger sequencing, and multiplex ligation‐dependent probe analysis, and blood mitochondrial DNA levels determined by quantitative polymerase chain reaction. Results Thirty‐five patients were found to carry homozygous or compound heterozygous pathogenic variants in the spastic paraplegia type 7 gene. Mean age at onset was 40 years (range, 12–63); 63% of spastic paraplegia type 7 patients were male, and three‐quarters of all patients had at least one allele with the c.1529C>T (p.Ala510Val) mutation. Eighty percent of the cohort showed a complicated phenotype, combining ataxia and progressive external ophthalmoplegia (65% and 26%, respectively). Parkinsonism was observed in 21% of cases. Analysis of blood mitochondrial DNA indicated that both patients and carriers of spastic paraplegia type 7 pathogenic variants had markedly lower levels of mitochondrial DNA than control subjects (228 per haploid nuclear DNA vs. 176 vs. 573, respectively; P < 0.001). Conclusions Parkinsonism is a frequent finding in spastic paraplegia type 7 patients. Spastic paraplegia type 7 pathogenic variants impair mitochondrial DNA homeostasis irrespective of the number of mutant alleles, type of variant, and patient or carrier status. Thus, spastic paraplegia type 7 supports mitochondrial DNA maintenance, and variants in the gene may cause parkinsonism owing to mitochondrial DNA abnormalities. Moreover, mitochondrial DNA blood analysis could be a useful biomarker to detect at risk families