Genetic control of murine hemagglutinin formation to H-2.5

When B10.D2 (H-2^d) mice are immunized with lymphoid cells from C57B1/10 (H-2 ^d ) and their antisera tested against B10.A (H-2 ^a ) target cells, only antibodies to H-2.5 are measured. The same is true for immunization of DBA/2 (H-2 ^d ) mice when their antisera are absorbed with B10.D2 cells prior to testing. Irrespective of the dose of immunogen administered, the primary hemagglutinin response of B10.D2 mice is significantly lower than that of DBA/2 mice and (B10.D2 × DBA/2)F₁ hybrids, but the secondary responses are similar. The low responsiveness of B10.D2 mice appears to be determined by a single dominant gene with incomplete penetrance; the gene is not linked to eitherH- 2, Hc, or the immunoglobulin allotype loci. In addition, the H-2.5 hemagglutinin response is susceptible to nongenetic influences. When antisera from B10.D2, devoid of H-2.5 hemagglutinins, were assayed in a complement-mediated cytotoxic test, they contained almost as much anti-H-2.5 activity as did the antisera from DBA/2 mice or (B10.D2 × DBA/2)F₁ hybrids. The possibility is discussed that the locus responsible for the deficient primary hemagglutinin response of B 10.D2 may not be determinant-specific but may affect hemagglutinin responses in general.     

Electron-paramagnetic-resonance studies on cobalt(II) carbonic anhydrase–sulphonamide complexes

Sulphonamide adducts of three Co(II) carbonic anhydrases were investigated by e.p.r. (electron paramagnetic resonance) at helium temperatures. The highly anisotropic 9 GHz spectra exhibited only three distinct features, with g values between 6.3 and 1.5. Such spectra arise from an electronic state with effective spin S'=(1/2), indicating that the high-spin (S=3/2) ground level is split into two spin doublets differing in energy by an amount large compared with the microwave quantum, but small in relation to thermal energies at ambient temperature. This situation would occur in a tetrahedral system suffering a large rhombic distortion. Calculations based on this model accounted for apparent discrepancies in integrated spectral intensities, and yielded magnetic moments in good agreement with independent measurements, especially in the case of certain small Co(II) complexes resembling the enzyme adducts in their e.p.r. signals. Precise sets of g values, reflecting a particular co-ordination geometry, were found to be representative of each enzyme variant and the type of sulphonamide inhibitor, whether benzocyclic or heterocyclic. A series of substituted benzene sulphonamides bound to the same enzyme gave rise to closely similar spectra despite a wide range of pK(i) values. Thus benzocyclic and heterocyclic sulphonamides were evidently held in the active-site cleft in characteristic orientations irrespective of side chains that might considerably influence the total binding strength. Visible absorption spectra of various sulphonamide adducts at room temperature showed a similar pattern of inhibitor dependence to the e.p.r. spectra, suggesting a correspondence between the co-ordination structures in liquid and frozen solution. E.p.r. spectra of the sulphonamide complexes were remarkable not only for their range of g values, but also for their variations in line-width and spin-lattice relaxation behaviour. Addition of glycerol to the medium produced marked enhancement in resolution, owing to the creation of a more homogeneous frozen matrix. The non-uniform spin relaxation was probably a consequence of the large anisotropy in effective g tensor.     

Alkaline phosphatase from pig kidney. Microheterogeneity and the role of neuraminic acid

Several alkaline phosphatases (EC 3.1.3.1) could be obtained from pig kidney brush-border membrane on extraction with butan-1-ol. Three of the multiple forms were separated by DEAE-cellulose chromatography and further purified. They form a regular series with different degrees of glycosylation (mainly owing to N-acetylneuraminic acid), of charge, of molecular weight, of stability to temperature, to pH and to urea, of minimal requirement for Mg²⁺ and of extractability by butan-1-ol. In contrast, the detectable antigenic sites, the inhibition by amino acids and the pH-dependency of K_m and V_max. were identical for these multiple forms. On treatment with neuraminidase, the multiple forms became identical in all their properties. It was therefore concluded that the microheterogeneity of alkaline phosphatase is due to different degrees of glycosylation at polypeptide chains which appear to be otherwise identical.     

Recombination of human erythrocyte apoprotein and lipid. II. Visualization of apoprotein-lipid bilayer complex by freeze-etching

Bilayers of human erythrocyte apoprotein-lipid complexes were made by dipping a mica plate through monolayers of the complex formed at the air-water interface. Stearic acid and erythrocyte lipid alone served as controls. Freeze-fracture images of the complex at high lipid surface pressures (30 dynes/cm) showed particles (average diameter, 109 Å ± 18 Å) similar to those of erythrocyte ghosts (average diameter, 102 Å ± 19 Å). Control surfaces were smooth. We conclude that part or all of the protein molecule penetrated into the lipid bilayer and that erythrocyte apoprotein-lipid complexes yield fracture faces similar to the native erythrocyte membrane.     

The Organically Handicapped Child—How Can the Family Physician Help?

The better his understanding of some of the ways in which an organic deficit might affect normal development of the handicapped child, the more able the family physician will be to offer guidance to the family aimed at preventing the development of secondary problems. He can thus be instrumental in helping a child achieve his maximal potential.First, it is important to take into account how the parents'' emotional and intellectual responses to having a defective child may interfere markedly in normal parent-child relationship. Second, ways in which each deficit will limit a child''s exposure to stimuli must not be over-looked. Third, one must consider how a deficit may indirectly distort the normal learning patterns when parents do not make age appropriate demands. Fourth, it is important to understand how specific interference in the area of language skills may cause further developmental retardation. Fifth, one must be aware of special problems that an organically handicapped child must face in the society outside of the family. Last of all, in an older child, one must consider the need for a full scale evaluation to sort out primary and secondary factors in the picture.     

Ethylene Oxide Gaseous Sterilization: II. Influence of Method of Humidification

The duration of the equilibration period between admission of water vapor and subsequent introduction of gaseous ethylene oxide to an evacuated sterilizer chamber was studied with respect to its effect on the inactivation of spores of Bacillus subtilis var. niger under simulated practical conditions. Introduction of a water-adsorbing cotton barrier between the spores and an incoming gas mixture of water vapor and ethylene oxide caused a marked increase in the observed thermochemical death time of the spore populations. This effect was negated by admission of water vapor one or more minutes prior to introduction of ethylene oxide gas. Increases in temperature and relative humidity of the system promoted passage of water vapor through the cotton barriers and diminished their effect.     

Zur Elektronenmikroskopie der Kerneinschlüsse im menschlichen Nebenhodenepithel

Zusammenfassung Es werden verschiedene Typen von Einschlußkörperchen im Karyoplasma der Epithelzellen des menschlichen Nebenhodenepithels beschrieben. Die verschieden strukturierten Kerninklusionen werden als eine Differenzierungsreihe aufgefaßt. Sie beginnt mit kleinen rundlichen Körperchen aus feinfädigem Material und führt über die Ausbildung von Anhäufungen dichter homogener Kugeln zu großen Vakuolen wechselnden Inhaltes.

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Summary Different types of inclusion bodies are described in the karyoplasm of the epithelial cells of the human epididymis. The structural differences between these inclusions are interpreted as being indicative of consecutive stages in the process of their formation. Thus small, spherical bodies consisting of a fine fibrous material are believed to be the initial stages in the formation of the inclusion bodies whereas the dense, homogenous globules are thought to represent a later stage. Large vacuoles containing different materials are regarded as the final stage in this process of differentiation.

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Herrn Professor Dr. W. Bargmann zum 60. Geburtstag gewidmet.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.