Endogenous copper is cytotoxic to a lymphoma in primary culture which requires thiols for growth

Summary With the use of bathocuproine sulfonate, a copper-specific chelator as an indicator, we have demonstrated that copper ions, present as a natural medium constituent are toxic to the growth of a lymphoma in primary culture and are principally responsible for the growth requirement of mercaptoethanol and other thiols. By chelating trace copper normally present in the medium, bathocuproine sulfonate retarded the oxidation of cysteine to poorly utilized cystine, thus permitting its direct utilization by the cells for growth.     

Seasonality in large-scale macroeconometric models

Macroeconomic indicators are typically appraised in seasonally adjusted form, and forecasts are often presented in a similar way (as annual changes, for example). Moreover, the quarterly macroeconomic models used in forecasting are commonly estimated from seasonally adjusted data. Nevertheless, these models can generate forecasts with seasonal patterns, and this paper assesses the cause and cure of this phenomenon. It is found that forecast seasonality is induced by seasonality in the various inputs: exogenous variables, residual adjustments, the dynamic specification of certain equations, and annual changes in policy variables. Series changing annually but observed quarterly are termed ‘intercalated series’, and are simple examples of periodic processes. Forecast seasonality can be removed by appropriate adjustment of all these inputs. Models containing explicit future expectations variables solved in a model-consistent manner are also considered: numerical sensitivity to the terminal quarter may result from terminal conditions that require adjustment when seasonality is present.     

Offset rate of action of muscarinic antagonists depends on their structural flexibility

Summary Time course measurements of the action of muscarinic antagonists were performed in the spontaneously beating carp atrium. Several high affinity drugs, which embody the quinuclidine structure were examined. The structural flexibility of these molecules was reflected in the dissociation of the drugs from the muscarinic receptor. The dissociation of rigid drugs was very much prolonged as compared to flexible drugs of the same affinity.We thank Prof. S. Lifson for helpful discussion and Mrs M. Bendikovsky for technical assistance. This work was supported by a USA-Israel Binational Science Foundation (BSF-Jerusalem) grant to Y. Lass.