Colorectal Cancers Mimic Structural Organization of Normal Colonic Crypts

Colonic crypts are stereotypical structures with distinct stem cell, proliferating, and differentiating compartments. Colorectal cancers derive from colonic crypt epithelia but, in contrast, form morphologically disarrayed glands. In this study, we investigated to which extent colorectal cancers phenocopy colonic crypt architecture and thus preserve structural organization of the normal intestinal epithelium. A subset of colon cancers showed crypt-like compartments with high WNT activity and nuclear β-Catenin at the leading tumor edge, adjacent proliferation, and enhanced Cytokeratin 20 expression in most differentiated tumor epithelia of the tumor center. This architecture strongly depended on growth conditions, and was fully reproducible in mouse xenografts of cultured and primary colon cancer cells. Full crypt-like organization was associated with low tumor grade and was an independent prognostic marker of better survival in a collection of 221 colorectal cancers. Our findings suggest that full activation of preserved intestinal morphogenetic programs in colon cancer requires in vivo growth environments. Furthermore, crypt-like architecture was linked with less aggressive tumor biology, and may be useful to improve current colon cancer grading schemes.     

Exclusion mapping of the X-linked dominant chondrodysplasia punctata/ichthyosis/cataract/short stature (Happle) syndrome: possible involvement of an unstable pre-mutation

Summary Homology with the mouse bare patches mutant suggests that the gene for the X-linked dominant chondrodysplasia punctata / ichthyosis / cataract / short stature syndrome (Happle syndrome) is located in the human Xq28 region. To test this hypothesis, we performed a linkage study in three families comprising a total of 12 informative meioses. Multiple recombinations appear to exclude the Xq28 region as the site of the gene. Surprisingly, multiple crossovers were also found with 26 other markers spread along the rest of the X chromosome. Two-point linkage analysis and analysis of recombination chromosomes seem to exclude the gene from the entire X chromosome. Three different mechanisms are discussed that could explain the apparent exclusion of an X-linked gene from the X chromosome by linkage analysis: (a) different mutations on the X chromosome disturbing X inactivation, (b) metabolic interference, i.e. allele incompatibility of an X-linked gene, and (c) an unstable pre-mutation that can become silent in males. We favour the last explanation, as it would account for the unexpected sex ratio (MF) of 1.21 among surviving siblings, and for the striking clinical variability of the phenotype, including stepwise increases in disease expression in successive generations.     

Electrorotation of lymphocytes—The influence of membrane events and nucleus

Electrorotation—the spin of cells in rotating high frequency electric fields—has been used to investigate properties of human peripheral blood lymphocytes. The rotation spectra of lymphocytes deviate from those of single shell spheres. The deviations are caused by the electrical properties of the nucleus in the cell interior.Electrorotation allows the distinction between successfully stimulated lymphocytes and unstimulated cells after application of concanavalin A. Notwithstanding the fact that only a proportion of the cells will be mitogenically stimulated we detected an enhanced cell membrane conductivity for the whole cell population immediately after the addition of mitogen.     

Protein shift and antigenic variation in the S-layer of Campylobacter fetus subsp. venerealis during bovine infection accompanied by genomic rearrangement of sapA homologs.

Campylobacter fetus subsp. venerealis isolated from a case of human vaginosis was inoculated into the uterus of a C. fetus-negative heifer. Isolates obtained weekly from the vaginal mucus exhibited variations in high-molecular-mass-protein profiles from that of the original inoculum, which had a dominant 110-kDa S-layer protein. Immunoblots of the weekly isolates with monoclonal antibody probes against the 110-kDa S-layer protein and other C. fetus S-layer proteins demonstrated antigenic shifts. Genomic digests of the isolates probed with a 75-mer oligonucleotide of the conserved sapA region also indicated that antigenic variation of the S-layer is accompanied by DNA rearrangement.     

Transparent Golgi Impregnations: A Way to Examine Both Details of Cellular Processes and Components of the Nerve Cell Body

A method is described by which the precipitate that normally fills impregnated cells in Golgi preparations is confined to a thin and transparent scattering of fine particles that defines the somata and cellular processes. The coating is stable enough to withstand counterstaining and thus makes possible direct evaluation of structural features not only of cellular processes but also of cytoplasmic components.     

Effects of disinfectants on Campylobacter jejuni

Because of the increasing recognition that Campylobacter jejuni is an important enteric pathogen of humans, we studied the effects of widely used disinfectants on the viability of this organism. At an inoculum size of 10(3) to 10(4) CFU/ml, 1.25 mg of hypochlorite per liter killed three strains within 1 min. At an inoculum size of 10(6) to 10(7) CFU/ml, 5 mg of hypochlorite per liter killed three strains within 15 min. Killing of similar concentrations of C. jejuni and Escherichia coli by hypochlorite was approximately the same. At the high inoculum, 0.15% phenolic compound, 10 mg of iodophor per liter, 1:50,000 quaternary ammonium compound, 70% ethyl alcohol, and 0.125% glutaraldehyde killed all three strains within 1 min. These studies demonstrate that, under the conditions we tested (pH 7.0; 24 to 26 degrees C), the recommended standard concentrations of disinfecting agents are adequate to destroy C. jejuni.     

Specific VDJ gene combinations contribute to the specificity of memory antibodies to the phosphorylcholine hapten.

Based on their fine specificity, two groups of antibodies against the phosphorylcholine (PC) hapten have been described. Group I antibodies react predominantly with the PC moiety of the hapten and group II are directed against the entire hapten including the azophenyl spacer to the protein carrier. We have analyzed the VH gene segment utilization of hybridomas from the memory response to PC by Southern blot analysis and nucleotide sequencing of the functional VDJ rearrangements. Three main specificities of anti-PC antibodies could be distinguished. Anti-PC hybridomas with group I fine specificity utilize the VH1-DFL 16.1-JH1 rearrangement. A major portion of group II antibodies recognized the phenyl-PC part and expressed the same VH1 gene in combination with a member of the SP2 family and JH1 or JH2. The other anti-PC antibodies either used the PJ14-DFL16-JH3 rearrangement in combination with a lambda 1 L chain or a member of the VGam3.8 VH family rearranged to the DFL16.1 and the JH3 gene segments. The PJ14 and VGam3.8 V gene expressing antibodies were directed to the phenyl group and were either not or barely inhibitable by PC chloride. Thus, specific VDJ gene combinations contribute to the fine specificity of antibodies in the memory response to the PC hapten. The use of the S107, Q52, and VGam3.8. VH gene families, together with FL16.1 or SP2 D segments and JH1, JH2, or JH3 results in different fine specificities to the PC, phenyl-PC, or the azophenyl moiety of the PC hapten. These fine specificities of the memory response use V, D, and J segments of the initial T15Id+ response in combination with gene segments usually related to phenyl specificity.     

Pigment architecture of the human telencephalic cortex

Summary Cortical lamination and parcellation of the retrosplenial region in the human brain is evaluated with the aid of frontal serial sections stained for nerve cells (15 m), myelin sheaths (100 m), and lipofuscin granules (800 m).For the most part, the retrosplenial region is buried in the depth of the sulcus corporis callosi covering the posterior parts of the cingulate gyrus. It lies between the supracallosal derivatives of the allocortex (fascia dentata, cornu ammonis, subiculum) and the mature parietal isocortex.The region can be subdivided into five areas. The transitory periallocortical Area ectosplenialis is followed by a richly differentiated proisocortical core displaying extremely externopyramidal, externoteniate, and astriate to unitostriate characteristics. The parvocellular core is averagely poor in pigment (Typus clarus) and rich in myelinated fibres (Typus dives). Minor structural differences allow for its subdivision into a lateral, an intermediate, and a medial retrosplenial field. The accompanying Area parasplenialis is adjacent to the equoteniate parietal isocortex. It is only weakly externopyramidal, externoteniate, and propebistriate. The already homotypical field shows an average pigmentation and myelin content. These structural features permit its classification as a belt area of the retrosplenial core.Supported by grants from the Deutsche Forschungsgemeinschaft     

Isotype-specific resistance against tolerance induction in SJL mice

Age-related changes in antibody response of SJL mice were examined in terms of isotype expression after treatment with immunogen or with immunogen, preceded by the molecule in normally tolerogenic form. We report here that tolerance induction and resistance to down regulation are isotype specific. Tolerance can be induced in terms of all detectable isotypes at the age of 5 weeks. In older SJL mice, tolerance to the carrier is found in IgM antibody, whereas there is resistance against down regulation in terms of IgG2a and IgG2b isotypes, and sensitization in terms of IgG3, IgG1, and IgA antibody. Furthermore, the degree of down regulation is determinant dependent. This was observed when older SJL mice, pretreated with the carrier in a normally tolerogenic form, were immunized with haptenated carrier and tested for their response to hapten and carrier determinants. In this case, IgA antibody shows tolerance to the hapten and sensitization by carrier determinants.     

Complement resistance of Borrelia burgdorferi correlates with the expression of BbCRASP-1, a novel linear plasmid-encoded surface protein that interacts with human factor H and FHL-1 and is unrelated to Erp proteins

The etiologic agent of Lyme disease, Borrelia burgdorferi, is capable of circumventing the immune defense of a variety of potential vertebrate hosts. Previous work has shown that interaction of host-derived complement regulators, factor H and factor H-like protein 1 (FHL-1), with up to five complement regulator-acquiring surface proteins (CRASPs) expressed by resistant B. burgdorferi sensu lato isolates conferred complement resistance. In addition expression of CRASP-1 is directly correlated with complement resistance of Borrelia species. This work describes the functional characterization of BbCRASP-1 as the dominant factor H and FHL-1-binding protein of B. burgdorferi. The corresponding gene, zs7.a68, is located on the linear plasmid lp54 and is different from factor H-binding Erp proteins that are encoded by genes localized on circular plasmids (cp32). Deletion mutants of BbCRASP-1 were generated, and a high affinity binding site for factor H and FHL-1 was mapped to the C terminus of BbCRASP-1. Similarly, the predominant binding site of factor H and FHL-1 was localized to the short consensus repeat 7. Factor H and FHL-1 maintain their cofactor activity for factor I-mediated C3b inactivation when bound to BbCRASP-1, and factor H is up to 6-fold more efficient in mediating C3b conversion than FHL-1. In conclusion, BbCRASP-1 (i). binds the host complement regulators factor H and FHL-1 with high affinity, (ii). is the key molecule of the complement resistance of spirochetes, and (iii). is distinct from the Erp protein family. Thus, BbCRASP-1 most likely contributes to persistence of B. burgdorferi and to pathogenesis of Lyme disease.