In this rapid commentary, a mini-review is given of the present state-of-knowledge regarding the etiology and epidemiology of the new coronavirus 2019-nCoV and the risks for developing Acute respiratory distress syndrome. The available knowledge on the viral genomics, molecular biology and pathogenicity of viruses of the Coronaviridae family and other Nidovirales, forms a helpful template for understanding the present pandemic outbreak. However, important questions remain unanswered about the underlying mechanism causing the very high case fatality ratios and mechanisms regarding severe (...) reactions like ARDS, fatal cardiac and renal failures, associated with a number of important comorbidity factors. Immunological reactions to lung alveoles in particular in late phase ARDS in SARS-like CoV diseases, so far may not have received enough attention. Finally a shortlist of questions for high priority further research is suggested. (shrink)

The Hygiene Hypothesis has been recognized as an important cornerstone to explain the sudden increase in the prevalence of asthma and allergic diseases in modernized culture. The recent epidemic of allergic diseases is in contrast with the gradual implementation of Homo sapiens sapiens to the present-day forms of civilization. This civilization forms a gradual process with cumulative effects on the human immune system, which co-developed with parasitic and commensal Helminths. The clinical manifestation of this epidemic, however, became only visible in (...) the second half of the twentieth century. In order to explain these clinical effects in terms of the underlying IgE-mediated reactions to innocuous environmental antigens, the low biodiversity of antigens in the domestic environment plays a pivotal role. The skewing of antigen exposure as a cumulative effect of reducing biodiversity in the immediate human environment as well as in changing food habits, provides a sufficient and parsimonious explanation for the rise in allergic diseases in a highly developed and helminth-free modernized culture. Socio-economic tendencies that incline towards a further reduction of environmental biodiversity may provide serious concern for future health. This article explains that the “Hygiene Hypothesis”, the “Old Friends Hypothesis”, and the “Skewed Antigen Exposure Hypothesis” are required to more fully explain the rise of allergy in modern societies. (shrink)

The highly ordered neuronal projections from the retina to the tectum mesencephali (optic tectum) in several vertebrate groups have been intensively studied. Several hypotheses so far have been proposed, suggesting mechanisms to explain the topographical and biochemical specificity of the retinotectal projections during ontogeny. In the present paper we compare the main hypotheses of retinotectal development with respect to the nature of specificity envisaged, the activity-dependence versus inheritance criterium and the strategy of argument, in casu the descriptive versus interferential type (...) of argument. Matching of the current developmental hypotheses and mechanisms for elimination or persistance of contralateral, respectively ipsilateral connections, is attempted with respect to the known neuroanatomical connectivity data in the amphibian optic tectum and with respect to the symmetry relations between ipsilateral and contralateral connection patterns described in amphibians and other vertebrate groups. Local mechanisms influencing the survival potential of synaptic contacts between retinal afferents and tectal neurons are probably essential for generating global symmetry patterns. Finally, a global topological approach is discussed with respect to its applicability in the amphibian retinotectal projection system. Basic assumptions of topological modeling appear to rely on anatomical and functional properties of the visual system like left-right symmetry, dichotomy, (absence of) convergence and segregation of fibers and neurons into columnar information units. It is concluded however, that more neuroanatomical, physiological and ultrastructural data are needed to establish a formalized operation model of the amphibian retinotectal system. (shrink)

Biological self reference idioms in brain-centered or nervous-system-centered self determination of the consious Self reveal an interesting contrast with biological self-determination by immunological self/non-self discrimination. This contrast is both biological and epistemological. In contrast to the consciousness conscious of itself, the immunological self-determination imposes a protective mechanism against self-recognition (Coutinho et al. 1984), which adds to a largely unconscious achievement of the biological Self (Popper 1977; Medawar 1959). The latter viewpoint is in contrast with the immunological Self-determination as an essentially (...) cognitive process as expressed in the analysis of Tauber (1994). Comparison of the immune system in vertebrates and invertebrates, according to new biological insights, has contributed to a better understanding of the relative role of innate (or inherited) immunity versus immunity acquired during each individual life. Also in this respect, immunological self-achievement shows both a striking analogy and a fundamental discrepancy with the activity of the nervous system. The analysis of immunological Self/non-self discrimination versus brain-centered self-determination adds to the understanding of the function paradigm in biological self-reference idioms, especially when regarding the importance of the connectivity notion in both systems. Adopting functional explanatory schemes for understanding immunological self-non-self discrimination, as well as for the understanding of functional mapping of the brain at (conscious) activity (Friston et al. 1993; Frith et al. 1995), forwards the notion of effective/functional connectivity. Network connectivity not only is a primary question in solving the dimensionality question for immunological ‘idiotypic networks’ (Jerne 1974a, b; 1984), it may also have an important value in describing phase transitions in the development of both immune and nervous systems. (shrink)