H-Y and antigens of the major histocompatibility complex.: H-Y and H-2D antigens are associated on unfixed lymphocytes and thymocytes but not on testicular cells

The results of an antibody blocking technique indicate that H-Y and H-2D antigens are close to one another on the surfaces of unfixed thymocytes and lymphocytes, but distant on testicular cells. The findings are the same using cells from mice of several inbred strains (C57BL/10, BALB/c, B6.H-2^k). The data indicate moreover that H-2K antigens and H-Y are distant on all cell types tested. The gonad specific H-Y receptor-presumed necessary for H-Y directed testicular differentiation is associated with neither H-2D nor H-2K antigens.     

Zur Praxis der Typenbestimmung von Mycobacterium tuberculosis

Zusammenfassung Es wird über Erfahrungen bei der Typenbestimmung von 127 Tuberkelbakterien-Stämmen berichtet, die aus menschlichen Untersuchungsstoffen (95), Organen perlsüchtiger Rinder (15) und Organen tuberkulöser Hühner (17) gezüchtet wurden. Zur Differenzierung zogen wir die kulturmorphologischen Eigenschaften, den Bromkresolpurpur-Nährboden (Wagener u.Mitscherlich), die Feststellung des O₂-Bedarfes (Lebek), die Katalase-Aktivität (Middlebrook), den Niacin-Test (Bönicke u.Lisboa), die Testung gegenüber Brenzschleimsäurehydracid (Bönicke u.Lisboa) und Tierversuche heran. Schwierigkeiten entstanden nur bei fermentschwachen und isoniazid-resistenten Stämmen beider Säugetiertypen der Tuberkelbakterien. Dabei verhielt sich keines der Verfahren immer typengerecht. Die Typendiagnose kann also nur unter Auswertung mehrerer Methoden gewonnen werden.Auf den kürzlich vonBönicke empfohlenen Nicotinamidase-Test zur Identifizierung schwierig einzuordnender, auch isoniazidresistenter Stämme wurde hingewiesen.Der Brenzschleimsäurehydrazid-Test und die Methode der Prüfung des O₂-Bedarfes eignen sich nach unseren Beobachtungen nicht für die Erkennung von Geflügeltuberkelbakterien.     

Yeast-expressed hantavirus Dobrava nucleocapsid protein induces a strong, long-lasting, and highly cross-reactive immune response in mice

In Europe, Dobrava virus (DOBV) carried by the yellow-necked field mouse Apodemus flavicollis is one of the hantaviruses that can cause severe hemorrhagic fever with renal syndrome in humans. For several hantaviruses, the nucleocapsid (N) protein has proven to be very immunogenic in humans and rodents and even can protect rodents against a virus challenge. To investigate the immunogenicity of DOBV N protein, BALB/c and C57BL/6 mice were immunized three times with a DOBV recombinant N (rN) protein expressed in yeast Saccharomyces cerevisiae together with complete Freund's, with incomplete Freund's, and without adjuvant, respectively. Mice of both strains elicited N-specific antibodies with end-point titers being as high as 1:1,000,000 in C57BL/6 mice. The antibodies induced by DOBV rN protein were highly cross-reactive to the rN proteins of hantaviruses Puumala and Hantaan. In both mice strains, DOBV rN protein induced N-specific antibodies of all IgG subclasses (IgG1, IgG2a, IgG2b, and IgG3), suggesting a mixed Th1/Th2 immune response. Taken together, yeast-expressed DOBV rN protein represents a promising vaccine candidate.     

Use of 3D reconstruction to correct for patient motion in SPECT

Patient motion occurring during data acquisition in single photon emission computed tomography (SPET) can cause serious reconstruction artefacts. We have developed a new approach to correct for head motion in brain SPECT. Prior to motion, projections are assigned to conventional projections. When head motion occurs, it is measured by a motion monitoring system, and subsequent projection data are mapped to 'virtual' projections. The appropriate position of each virtual projection is determined by applying the converse of the patient's accumulated motion to the actual camera projection. Conventional and virtual projections, taken together, form a consistent set that can be reconstructed using a three-dimensional (3D) algorithm. The technique has been tested on a range of simulated rotational movements, both within and out of the transaxial plane. For all simulated movements, the motion corrected images exhibited better agreement with a motion free reconstruction than did the uncorrected images. This technique may help to overcome one of the major remaining limitations on image quality and quantitative accuracy in SPECT.     

Analysis of the Equalization of Inverted Repeats and Neurovirulence Using a Pseudorabies Virus Mutant Strain Altered at the Ul/Ir Junction

A recombinant pseudorabies (Aujeszky’s disease) virus (PrV) designated as vE16lac was constructed by deleting a 3-kbp DNA segment spanning the junction of long and short components of the viral genome, and by replacing the deleted segment with a lacZ-expression cassette. The aim of constructing this mutant was (a) to determine whether the terminal repeat (Tr) can serve as a template for the regeneration of the internal repeat (Ir), and (b) whether this deletion causes a reduction in the neuroinvasiveness of the virus. To analyze the mechanism of equalization, revertant viruses were selected and structurally characterized from vE16lac infection of PK-15 cells, mice and pigs. Because all revertants acquired Ir sequences identical to that of the wild-type virus, the equalization process occurred using the Tr as a template to reconstitute the Ir. We also found that the recombinant virus vE16lac was virulent in both pigs and mice. The data are discussed in view of studies performed with similar PrV mutants by other authors (Rall et al., 1992, Dean and Cheung, 1995 and Dean et al., 1996). This revised version was published online in July 2006 with corrections to the Cover Date.     

Dielectric properties of a liquid crystalline siloxane copolymer

An investigation on the molecular dynamics of a liquid crystalline side chain polymer using the dielectric relaxation method on oriented samples in the frequency range of 0,1 to 10 000 kHz is presented. The compound under investigation is a polysiloxane copolymer with two different mesogenic side chains and a phase sequence glassy-smectic A-nematic-isotropic. Three main relaxation processes are found and assigned to the rotation of the side chains around the main chain, the glass transition process coupled with side chain motions, and a local motion in the glassy state, respectively. Evidence is found for a layered arrangement of the polymer main chain in the smectic phase and for a parallel correlation between the transverse components of the dipole moments.     

Polymerisationsauslösung mit substituierten ethanen, 2. Trennung der Oligomeren aus Methylmethacrylat und 1,1,2,2-Tetraphenyl-1,2-diphenoxyethan

The telechelics 1 from methyl methacrylate and 1,1,2,2-tetraphenyl-1,2-diphenoxyethane, can be separated by adsorption chromatography. The structure of the dimers and trimers was identified by ¹H NMR-spectroscopy. The free radical oligomerization is a process in which the syndiotactic structure is favoured above the isotactic one.