TCR+/BCR+ dual-expressing cells and their associated public BCR clonotype are not enriched in type 1 diabetes.

Ahmed and colleagues recently described a novel hybrid lymphocyte expressing both a B and T cell receptor, termed double expresser (DE) cells. DE cells in blood of type 1 diabetes (T1D) subjects were present at increased numbers and enriched for a public B cell clonotype. Here, we attempted to reproduce these findings. While we could identify DE cells by flow cytometry, we found no association between DE cell frequency and T1D status. We were unable to identify the reported public B cell clone, or any similar clone, in bulk B cells or sorted DE cells from T1D subjects or controls. We also did not observe increased usage of the public clone VH or DH genes in B cells or in sorted DE cells. Taken together, our findings suggest that DE cells and their alleged public clonotype are not enriched in T1D. This Matters Arising paper is in response to Ahmed et al. (2019), published in Cell. See also the response by Ahmed et al. (2021), published in this issue.

Gustave-Adolphe Hirn, the mechanical equivalent of heat, and the conservation of energy.

Alsatian engineer Gustave-Adolphe Hirn is best known to historians of science for his experimental determination of the mechanical equivalent of heat, first published in 1855. Since the 1840s, that equivalent has been closely associated with the conservation of energy, indeed often conflated with it. Hirn was one of Thomas Kuhn's twelve 'pioneers' whose work he deemed relevant to the ostensible 'simultaneous discovery' of energy conservation. Yet Hirn never wholeheartedly embraced energy conservation. After reviewing his experimental work, his philosophical reflections, and his response to developments in heat theory, this article identifies three factors as having played central roles in this regard: Hirn's deepest concerns were ontological, not energetic; none of the concepts basic to his natural philosophy were appropriate stand-ins for a quantitatively conserved energy; and, accurately reflecting the most common interpretation of the principle of the conservation of energy from the 1860s on - as exemplified already by Helmholtz in 1847 - Hirn associated its corpuscular-mechanical underpinning with the despiritualizing materialism he saw as dominating contemporary science. Hence although Hirn's natural philosophy embraced sentiments quite in the spirit of the conservation of energy, he never explicitly subscribed to that principle.

[Depressive Disorders in Adolescence: Current State of Studies Concerning the Microbiota-Gut-Brain Axis]. / Depressive Störungen in der Adoleszenz: Aktuelle Studienlage zur Mikrobiota-Darm-Hirn-Achse.

Depressive Disorders in Adolescence: Current State of Studies Concerning the Microbiota-Gut-Brain Axis Abstract. Depressive disorders increase during adolescence and often lead to significant impairment in affected individuals - despite treatment. Current research efforts aim to further investigate the pathophysiology of depression, considering the influence of gut microbiota on the gut-brain axis. The present narrative review outlines the current state of studies of the microbiota-gut-brain axis in depressive disorders as well as the direct and indirect interactions in adolescence. Besides providing promising results from animal studies, studies on the microbiota-gut-brain axis in adults suffering from depressive disorders are growing steadily. In depressed adolescents, however, the study situation is still marginal, making a recommendation for the supplementation of probiotics and prebiotics in depressed children and adolescents impossible according to the current state of research. Against the background of a very limited number of studies involving adolescents with depressive disorders, the interactive role of the microbiota-gut-brain axis in adolescent development should receive special attention in future research projects.

Regression I. Experimental approaches to regression.

The concept of regression is considered with an emphasis on the differences between the positions of Freud and Jung regarding its significance. The paper discusses the results of experimental analyses of individual experience dynamics (from gene expression changes and impulse neuronal activity in animals to prosocial behaviour in healthy humans at different ages, and humans in chronic pain) in those situations where regression occurs: stress, disease, learning, highly emotional states and alcohol intoxication. Common mechanisms of regression in all these situations are proposed. The mechanisms of regression can be described as reversible dedifferentiation, which is understood as a relative increase of the representation of low-differentiated (older) systems in the actualized experience. In all of the cases of dedifferentiation mentioned above, the complexity of the systemic organization of behaviour significantly decreases.

Le concept de régression est étudié en mettant l'accent sur les différences entre les positions de Freud et celles de Jung concernant sa portée. L'article discute les résultats des analyses expérimentales de dynamiques de l'expérience individuelle (de changements dans l'expression des gènes et de l'activité des réflexes neuronaux chez les animaux aux comportements pro-sociaux chez des humains en bonne santé et à des âges de vie divers, et chez des humains en situation de souffrance chronique) dans ces situations où se produit la régression: le stress, la maladie, l'apprentissage, les états hautement émotionnels et l'intoxication par l'alcool. Les mécanismes communs de régression dans toutes ces situations sont présentés. Les mécanismes de régression peuvent être décrits en tant que dé-différentiation réversible, ce qui est interprété comme un accroissement relatif de la représentation de systèmes peu-différenciés (plus vieux) dans l'expérience actualisée. Dans tous les cas de dé-différentiation mentionnés plus haut, la complexité de l'organisation systémique du comportement décroit de manière significative.

Se considera el concepto de regresión, con énfasis en las diferencias entre Freud y Jung en lo que concierne a su significado. El trabajo desarrolla los resultados de análisis experimentales sobre dinámicas experienciales individuales (desde cambios en la expresión genética y actividad neuronal en animales a conductas prosociales en humanos saludables en diferentes edades, y humanos en dolor crónico) en aquellas situaciones donde la regresión ocurre: estrés, enfermedad, aprendizaje, estados altamente emocionales e intoxicación alcohólica. Se proponen mecanismos comunes de regresión en todas estas situaciones. Los mecanismos de regresión pueden describirse como de-diferenciación reversible, la cual es comprendida como un incremento relativo de la representación de sistemas de baja-diferenciación (antiguos) en la experiencia actualizada. En todos los casos de de-diferenciación mencionados anteriormente, la complejidad de la organización sistemática de conducta decrece significativamente.

Regression II. Development through regression.

As shown in our previous paper ('Regression I. Experimental approaches to regression', JAP, 65, 2, 345-65), the common mechanism of regression can be described as reversible dedifferentiation, which is understood as a relative increase of the proportion of low-differentiated (older) systems in actualized experience. Experimental data show that regression following disease (chronic tension headache) is followed by adaptation and an increase in system differentiation in that experience domain which contains systems responsible for that adaptation. The results of mathematical modelling support the idea that reversible dedifferentiation can be one of the mechanisms for increasing the effectiveness of adaptation through learning. Reversible dedifferentiation, which is phenomenologically described as regression, is a general mechanism for restructuring the organism-environment interactions in situations where behaviours that were effective in the past become ineffective. Reversible dedifferentiation has evolved as a component of adaptation when new behaviours are formed and large-scale modifications in the existing behaviours are required in the face of changes in the external and/or internal environment. Thus, the authors believe that this article provides evidence for Jung's view that regression is not only a 'return' to past forms of thinking, affects and behaviour, but that regressive processes provide a significant impetus for psychological growth and development.

Comme nous l'avons montré dans notre article précédent (« Régression I. Les approches expérimentales de la régression ¼), le mécanisme propre à la régression peut être décrit en tant que dé-différentiation réversible, ce que l'on peut comprendre comme une hausse relative de la proportion de systèmes peu différentiés (plus vieux) dans l'expérience actualisée. Les données expérimentales montrent que la régression suite à une maladie (mal de tête de tension chronique) est suivie par une adaptation et un accroissement dans la différentiation des systèmes dans le domaine d'expérience qui contient les systèmes responsables de cette adaptation. Les résultats de la modélisation mathématique soutiennent l'idée que la dé-différentiation réversible peut être l'un des mécanismes pour accroitre l'efficacité de l'adaptation par l'apprentissage. La dé-différentiation réversible, qui est décrite phénoménologiquement comme régression, est un mécanisme général pour restructurer les interactions organisme-environnement dans des situations où les comportements qui fonctionnaient par le passé sont devenus inefficaces. La dé-différentiation réversible a évolué comme un élément de l'adaptation quand de nouveaux comportements se développent et que des changements dans l'environnement extérieur ou intérieur requièrent des modifications à grande échelle dans les comportements existants. Ainsi, les auteurs pensent que cet article apporte un soutien à la perspective de Jung selon laquelle la régression n'est pas seulement un « retour ¼ à des formes anciennes de fonctionnement, d'affects et de comportement, mais que les processus régressifs fournissent un élan significatif pour la croissance et le développement psychologiques.

Como hemos mostrado en nuestros trabajos previos ('Regresión I. Abordajes experimentales hacia la regresión'), el mecanismo común de la regresión puede ser descripto como desdiferenciación reversible, el cual es comprendido como un relativo incremento en la proporción de sistemas de baja-diferenciación en la experiencia actual. Data experimental muestra que la regresión luego de una enfermedad (tensión de cabeza crónica) es seguida por la adaptación y por un incremento en la diferenciación de sistemas en aquel dominio de la experiencia, que contiene sistemas responsables para tal adaptación. Los resultados del modelo matemático sostienen la idea de que la desdiferenciación reversible puede ser uno de los mecanismos para incrementar la efectividad de la adaptación a través del aprendizaje. La desdiferenciación reversible, la cual fenomenológicamente se describe como regresión, es un mecanismo general para restructurar las interacciones entre el organismo y el medio ambiente, en situaciones en las que las conductas que eran efectivas en el pasado se vuelven ineficaces. La desdiferenciación reversible ha evolucionado como un componente de la adaptación cuando se forman nuevas conductas y se requieren modificaciones a gran escala en las conductas existentes frente a los cambios en el medio ambiente externo y/o interno. Así, los autores consideran que el artículo proporciona evidencia a la perspectiva de Jung sobre la regresión, no solamente como un 'retorno' a formas de pensar, sentir y actuar del pasado sino que los procesos regresivos proveen un estímulo significativo para el desarrollo y el crecimiento psicológico.

On matters of mind and body: regarding Descartes.

In this paper the author considers Descartes' place in current thinking about the mind-body dilemma. The premise here is that in the history of ideas, the questions posed can be as significant as the answers acquired. Descartes' paramount question was 'How do we determine certainty?' and his pursuit of an answer led to cogito ergo sum. His discovery simultaneously raised the question whether mind is separate from or unified with the body. Some who currently hold that brain and subjectivity are unified contend that the philosopher 'split' mind from body and refer to 'Descartes' error'. This paper puts forward that Descartes' detractors fail to recognise Descartes' contribution to Western thought, which was to introduce the Enlightenment and to give a place to human subjectivity. Added to this, evidence from Descartes' correspondence with Princess Elisabeth of Bohemia supports the conclusion that Descartes did in fact believe in the unity of mind and body although he could not reconcile this rationally with the certainty from personal experience that they were separate substances. In this Descartes was engaged in just the same dilemma as that of current thinkers and researchers, a conflict which still is yet to be resolved.

[Minor Head Injury ­ a Silent Epidemic]. / Mildes Schädel-Hirn-Trauma - eine stille Epidemie.

The vast majority out of the 20 000 patients annually hospitalized after sustaining a head injury belong to the minor head injury/cerebral concussion continuum. Fortunately, most of the patients show full recovery after days to weeks. However, about 15 % of these patients suffer from prolonged up to permanent sequels potentially impairing their quality of life to a considerable extent. This especially holds true for those who suffer from recurrent minor head injuries (i.e. victims from contact sport accidents). Unfortunately, many of these patients are never diagnosed in an appropriate way and therefore looked at as hypochondriacs or simulants. This prevents adequate rehabilitation and support. This review aims to present current knowledge about pathophysiology and clinical features of minor head injuries and to give some information about diagnostics and treatment according to current guidelines.