Keramadine,a novel antagonist of serotonergic receptors isolated from the okinawan sea sponge Agelas sp.

A new bromine-containing alkaloid, keramadine, has been isolated from the Okinawan sea sponge Agelas sp. as a novel antagonist of serotonergic receptors and its structure has been elucidated by n.m.r. spectrometry.     

Pulmonary toxicity of indium arsenide and arsenic selenide following repeated intratracheal instillations to the lungs of hamsters

Chronic toxicity of indium arsenide (InAs) and arsenic selenide (As₂Se₃) was studied in male Syrian golden hamsters which received InAs or As₂Se₃ particles, each containing a total dose of 7.5 mg of arsenic, by intratracheal instillations once a week for 15 weeks. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During their total lifespan, the cumulative body weight gain of the hamsters in the InAs group was suppressed significantly compared with that in the control group, but not in the As₂Se₃ group when compared with that in the control group. However, the survival rate for the InAs group was significantly higher compared with the control group, but not for the As₂Se₃ group when compared with the control group. During the animals' total lifespan, one lung adenoma was seen in the 27 hamsters in the InAs group and one lung adenoma in the 23 hamsters in the control group. No tumors of the lung were observed in the As₂Se₃ group. Malignant tumors outside the lung appeared in four hamsters in the InAs group and in two in the As₂Se₃ group. No non-lung malignant tumours were seen in the control group. Total tumor incidence rates were 25.9% (7/27) in the InAs group, 10.3% (3/29) in the As₂Se₃ group and 8.7% (2/23) in the control group. There were therefore no significant differences in tumor incidence between the InAs or the As₂Se₃ group, and the control group. Regarding histopathological findings in the lung, incidence rates of proteinosis-like lesions, pneumonia, metaplastic ossification and emphysema were seen only in the InAs group, and alveolar or bronchiolar cell hyperplasia observed in both the InAs and the As₂Se₃ groups were at significantly higher rates than those in the control group. From these results, it was concluded that InAs and As₂Se₃ particles could induce pulmonary toxicity when instilled intratracheally into hamsters. A great deal of attention should be paid to the toxicity of both InAs and As₂Se₃, even though in this study the adverse health effects of As₂Se₃ appeared to be less than those of InAs.     

Water molecules in a protein cavity detected by a statistical-mechanical theory

Four water molecules confined in a small cavity of hen egg-white lysozyme were detected by means of the three-dimensional (3D) RISM theory, a statistical-mechanical theory of molecular solutions. This is the first theoretical realization of confined molecules in a protein without making nonsense tricks, such as placing the molecules in the space a priori. Possible impacts which the result may have on biochemistry and biophysics, including the molecular recognition, enzymatic reactions, etc., are discussed.     

Sharpness of the Korányi approach region

We prove a Littlewood-type theorem which shows the sharpness of the Korányi approach region for the boundary behavior of Poisson-Szegö integrals on the unit ball of . Our result is stronger than Hakim and Sibony (1983).

     

Isobar-hole doorway states and π-16O scattering

We describe and apply the isobar-hole approach to intermediate energy pion-nucleus reactions. Pion propagation, nucleon and isobar binding, Pauli restrictions and Δ propagation are calculated explicitly within a shell model framework. Intermediate coupling to multihole channels, for example through pion absorption, is treated phenomenologically through an isobar spreading potential. We find strongly collective Δ-hole states, leading to a reformulation of the approach in an extended schematic model. This entails systematic construction of a Δ-hole doorway state basis within which the Δ-hole propagator is evaluated. We find that this doorway space can be truncated at very low dimensionality while preserving accuracy, thereby simplifying the calculations appreciably. We make a detailed comparison between the theoretical results and recent data for π⁺ — ¹⁶O scattering in the pion energy range 50–340 MeV. Nonresonant πN interactions and the π-nucleus Coulomb interaction are included in the calculations. The data is reproduced quite well both below and in the resonance region, and we discuss in detail the role of various dynamical mechanisms. Above the resonance, the calculations are far less successful. We discuss possible shortcomings, stressing the role of inclusive pion-nucleus reactions for revealing the important dynamics. As a test of the Δ spreading potential used for describing elastic scattering, we calculate the total cross section for pion absorption. The result agrees reasonably well with the available data.