Beziehungen zwischen phagozytierenden,virusinfizierten Myeloblasten des Huhnes in vitro und den «gray bodies»

Summary The so-called gray bodies in chicken myeloblasts infected with the myeloblastose virus are phagocytized cell debris. Some difficultues concerning this virus-cell-system are pointed out.

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Die Arbeit wurde unterstützt durch Research grant No. C-4572 an die Duke University von National Cancer Institute, National Institutes of Health, Public Health Service, durch Grant No. E-84A von der American Cancer Society, Inc. und durch den Dorothy Beard Research Fund.     

Approach to a quantitative differentiation between the respiratory effects evoked from the lung stretch and the lung deflation receptors during thoracic compression

Zusammenfassung Die beiden Annahmen, dass sich bei Thoraxkompression die Verminderung der Impulssequenz der Lungendehnungsrezeptoren analog zum Lungenentdehnungsreflex auswirke, und dass sich dessen inspiratorische Atmungseffekte zu jenen des Lungenkollapsreflexes addieren, erscheinen gerechtfertigt. Diese Annahmen ermöglichen eine quantitative Differenzierung zwischen dem respiratorischen Einfluss der Lungendehnungs-und Lungenkollapsrezeptoren bei Thoraxkompression. Damit können die auf die Erregung der Lungenkollapsrezeptoren zu beziehenden Atmungsveränderungen (f,I/E) erstmals isoliert und quantitativ dargestellt werden.

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Presented at the 2nd Meeting of the Swiss Physiological Society, Zürich, 8 November 1969.     

Unusual activity of the Sun during recent decades compared to the previous 11,000 years

Direct observations of sunspot numbers are available for the past four centuries, but longer time series are required, for example, for the identification of a possible solar influence on climate and for testing models of the solar dynamo. Here we report a reconstruction of the sunspot number covering the past 11,400 years, based on dendrochronologically dated radiocarbon concentrations. We combine physics-based models for each of the processes connecting the radiocarbon concentration with sunspot number. According to our reconstruction, the level of solar activity during the past 70 years is exceptional, and the previous period of equally high activity occurred more than 8,000 years ago. We find that during the past 11,400 years the Sun spent only of the order of 10% of the time at a similarly high level of magnetic activity and almost all of the earlier high-activity periods were shorter than the present episode. Although the rarity of the current episode of high average sunspot numbers may indicate that the Sun has contributed to the unusual climate change during the twentieth century, we point out that solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades.     

Cadherin 23 is a component of the tip link in hair-cell stereocilia

Mechanoelectrical transduction, the conversion of mechanical force into electrochemical signals, underlies a range of sensory phenomena, including touch, hearing and balance. Hair cells of the vertebrate inner ear are specialized mechanosensors that transduce mechanical forces arising from sound waves and head movement to provide our senses of hearing and balance; however, the mechanotransduction channel of hair cells and the molecules that regulate channel activity have remained elusive. One molecule that might participate in mechanoelectrical transduction is cadherin 23 (CDH23), as mutations in its gene cause deafness and age-related hearing loss. Furthermore, CDH23 is large enough to be the tip link, the extracellular filament proposed to gate the mechanotransduction channel. Here we show that antibodies against CDH23 label the tip link, and that CDH23 has biochemical properties similar to those of the tip link. Moreover, CDH23 forms a complex with myosin-1c, the only known component of the mechanotransduction apparatus, suggesting that CDH23 and myosin-1c cooperate to regulate the activity of mechanically gated ion channels in hair cells.