Ultrastructural alterations in ciliary cells exposed to ionizing radiation

Summary Early effects of ionizing radiation were investigated in an experimental in vitro system using the ciliary cells of the tracheal mucous membrane of the rabbit, irradiated at 30° C and at more than 90% humidity. The changes in physiological activities of the ciliary cells caused by irradiation were continuously registered during the irradiation. The specimens were examined immediately after irradiation electron microscopically. The morphological changes in irradiated material after 10–70 Gy are compared with normal material. After 40–70 Gy, scanning electron microscopy revealed the formation of vesicles on cilia, and club-like protrusions and adhesion of their tips. After 30–70 Gy, a swelling of mitochondrial membranes and cristae was apparent transmission electron microscopically. The membrane alterations caused by irradiation are assumed to disturb the permeability and flow of ATP from the mitochondria, which in turn leads to the recorded changes in the activity of the ciliated cells.This investigation was supported by grants from Konung Gustaf V:s Jubileumsfond, John and Augusta Perssons Stiftelse, B. Kamprads Fond, the Faculty of Medicine, University of Lund, Sweden and the Swedish Medical Research Council (No. B77-17X-03897-05)The authors are greatly indebted to Miss Inger Norling, Miss Marianne Palmegren and Miss Birgitta Sandström for their excellent technical assistance     

The mechanism of energy conservation and transduction by mitochondrial cytochrome c oxidase

Oxidation of ferrocytochrome c by molecular oxygen catalysed by cytochrome c oxidase (cytochrome aa₃) is coupled to translocation of H⁺ ions across the mitochondrial membrane. The proton pump is an intrinsic property of the cytochrome c oxidase complex as revealed by studies with phospholipid vesicles inlayed with the purified enzyme. As the conformation of cytochrome aa₃ is specifically sensitive to the electrochemical proton gradient across the mitochondrial membrane, it is likely that redox energy is primarily conserved as a conformational “strain” in the cytochrome aa₃ complex, followed by relaxation linked to proton translocation. Similar principles of energy conservation and transduction may apply on other respiratory chain complexes and on mitochondrial ATP synthase.     

Functional responses to prey density ofEphedrus cerasicola [Hym.: Aphidiidae], an aphidiid parasitoid ofMyzus persicae [Hom.: Aphididae]

The functional responses of the parasitoidEphedrus cerasicola Starý parasitizingMyzus persicae (Sulzer) on a paprika plant, were studied for single females at different host densities (1 to 120 aphids per 1.8 dm³) during 3 different time periods (1 hr, 6 hrs, 24 hrs) at 21 °C. The response during 1 hr was curvilinear and is described by the random parasite equation according toRogers (1972). A maximum of 5–6 aphids could be parasitized during 1 hr. After 6 hrs, the response was linear, although it showed a slight sigmoid trend. In the 24-hr experiment, the response was curvilinear, but due to high rate of parasitization together with superparasitism no curve was estimated. The area of discovery was calculated for all densities and exposure times and ranged from 0.15 to 0.79 (1 hr), 0.69 to 1.96 (6 hrs), and 0.81 to 3.21 (24 hrs).     

Thermal Rearrangement of 4-Alkyl-1,2,4-triazoles. Rearrangements in the Crystalline State

Studies of the thermolyses of 4-alkyl substituted 1,2,4-triazoles was reviewed. They were observed to rearrange at 200–350 °C to the corresponding 1-alkylated triazoles. When substituted in the 4-position with aryl- or vinylic substituents the triazoles were inert to thermolysis, contrary to what was observed for the 4-alkyl- and 4-allyl substituted systems. The mechanisms for the reactions were elucidated, e.g., by studies of substituents effects and by kinetic measurements in solution as well as for the neat samples. Reactions in solutions were slow. The rearrangements in melts of the neat triazoles readily proceeded to the products, and were proposed to take place via a series of nucleophilic displacement steps. X-ray crystallographic measurements of selected structures, showed that the interatomic distances and angles between the relevant atoms in these structures, to a large degree resembled the geometry expected for the S_N2-type transition states proposed for the rearrangement mechanism. Thus, thermolyses of a series of triazole structures at temperatures below their melting points, confirmed that rearrangements actually did take place. The “kinetics” of the reactions in the crystalline state were investigated and rate constants and thermodynamic data were correlated with the structural characteristics of the crystals.     

Miracidia of Schistosoma japonicum: approach and attachment to the snail host

Schistosoma japonicum miracidia swim directed along a chemical gradient toward the snails Oncomelania hupensis and Biomphalaria glabrata, and they turn back when the concentration of attractive chemicals decreases. The host signal for this chemotactic response has a molecular weight of more than 30,000. When swimming miracidia encounter the surface of O. hupensis or agar containing O. hupensis snail-conditioned water (SCW) they perform the host-specific responses "contact with return," "repeated investigation," and "attachment," but they do not exhibit such behavior when encountering B. glabrata surface or agar containing B. glabrata SCW. Thus S. japonicum miracidia respond to different host signals when they approach snails than when they attach to snails.     

Alginate as immobilization material: III. Diffusional properties

The rate of diffusion of serum albumin (MW 6.9 x 10(4) D) out of beads of calcium alginate gels depends upon the concentration and uronic acid composition of the alginate (ManA/GulA ratio), the conditions under which the beads are produced, the pH, and the temperature. The diffusion coefficient decreases with increasing alginate concentration, and (ManA/GulA) ratio and with decreasing pH. Diffusion out of the beads, in which the alginate is uniformly distributed (homogeneous gel), is faster than out of the beads in which the alginate is concentrated at the surface (inhomogeneous gel). The temperature dependence of the diffusion coefficient follows the Arrhenius law, with an activation energy of approximately 23 kJ x mol(-1).     

Protein utilization during starvation in fat and lean Svalbard ptarmigan (Lagopus mutus hyperboreus)

Summary Body protein sparing during starvation has been examined in fat and lean Svalbard ptarmigan. Protein utilization was determined from daily N excretion and from the rate of decrease in body mass. Changes in plasma concentrations of -hydroxybutyrate, free fatty acids, glucose, and uric acid were also recorded. When fat birds were starved for 15 days protein catabolism initially fell (phase I) and was thereafter kept low (phase II). This was evident from the temporal pattern in both N excretion and body mass loss. In two birds, N excretion eventually increased, revealing enhanced protein catabolism and thus a third phase of starvation. Changes in protein utilization were paralleled by changes in plasma uric acid. Approximately 9% of the energy demand was covered by breakdown of body protein during phase II. The importance of fat catabolism in providing energy was indicated by markedly elevated plasma levels of -hydroxybutyrate and free fatty acids. When lean birds were starved for 5 days there appeared to be no phase II. The temporal pattern of body mass loss indicated phase I and III but that of N excretion only phase III. The relative contribution of body protein to energy demand increased from 22% at day 2 to 41% at the end of starvation and was paralleled by increased plasma uric acid. When data from lean and fat birds were pooled, the changes in uric acid and N excretion were highly correlated (r=0.92, P<0.001), indicating that plasma uric acid is a reliable index of protein breakdown in starving Svalbard ptarmigan. In conclusion, starving fat Svalbard ptarmigan have a much greater capacity to spare body protein than lean birds. Fat birds effectively reduce protein catabolism and maintain this at a low level whereas starving lean birds increase protein catabolism.Abbreviations -OHB -hydroxybutyrate - BM body mass - BMR basal metabolic rate; dne daily nitrogen excretion - FFA free fatty acids - MR metabolic rate     

The clinical significance of HAMA in patients treated with mouse monoclonal antibodies

Twenty-four patients were analyzed for the development of HAMA (human antimouse antibodies) after being treated with repeated doses (200–500 mg) of the mouse monoclonal antibody (MAb) 17-1A. All patients developed anti-17-1A IgG antibodies, and most of them also developed IgM antibodies. In only two patients could immune complexes be demonstrated. Allergic reactions were rare (1.9%). In an extended study, a further 19 patient were analyzed for an idiotypic response. Forty-one out of 43 patients developed antiidiotypic antibodies (ab₂), and 20 of these also antianti-idiotypic antibodies (ab₃). Ab₃ ⁺ patients responded significantly better (p=0.01) and survived longer (p<0.001) compared to ab₃ ⁻ patients. In this study, we showed that MAb 17-1A could be repeatedly given on a safe basis. The development of high titers of HAMA did not cause significant clinical problems when further repeated infusions of MAb 17-1A were given. The development of an idiotypic response also indicate that the induction of HAMA might be beneficial and not harmful to the patient.