Immunity to extracellular matrix antigens is associated with ultrastructural alterations of the stroma and stratified epithelium basement membrane in the skin of Hashimotos thyroiditis patients.

Employing purified extracellular matrix (ECM) proteins, i.e. type I, III, IV and V collagens (CI, CIII, CIV, CV), laminin (LM) and fibronectin (FN), as antigen sources we detected autoantibodies to conformational and/or denatured ECM antigens among 34 of 50 sera obtained from Hashimotos thyroiditis (HT) patients and 6 of 51 control sera obtained from non-autoimmune thyroid disease patients and healthy donors (HT sera vs. control sera p=4 x 10-9). Reactivity to conformational antigens, mostly due to autoantibodies of the IgG isotype, was observed in 30/50 HT sera and in 6/51 control sera (p=3.5 x 10-7) and was not always concomitant with that to linear antigens, found in 23/50 HT and in 6/51 control sera (p=1.6 x 10-4). Ultrastructural analysis of skin biopsies obtained from 18 HT patients without symptomatic cutaneous diseases revealed defects of the stratified squamous epithelium basement membrane in 11/18, alterations of the stroma in 13/18 and both basement membrane and stromal defects in 9/18. Interestingly, 13/13 (p=0.012) and 9/11 (p=0.012) patients with stromal and basement membrane defects respectively, exhibited serum antibodies to at least one ECM antigen involved in the organization of the altered tissue compartment. Lastly, 10/18 skin biopsies presented immunoglobulin (Ig) and/or complement (C3) deposits along the cutaneous basement membrane zone (BMZ) or in the papillary dermis and 9/10 sera from the same patients simultaneously showed antibodies to at least one ECM antigen involved in the organization of these two skin compartments. Besides, 8/11 HT patients with basement membrane defects exhibited Ig or C3 deposits along the BMZ. Our findings suggest that autoantibodies to ECM molecules might contribute to the development of asymptomatic extra-thyroid skin diseases in HT patients.

Periodic trends in electrode-chemisorbate bonding: benzonitrile on platinum-group and other noble metals as probed by surface-enhanced Raman spectroscopy combined with density functional theory.

Detailed intramolecular vibrational spectra obtained by means of surface-enhanced Raman scattering (SERS) for benzonitrile adsorbed on seven electrode surfaces-four Pt-group metals (platinum, palladium, rhodium, and iridium) and the Group IB metals (copper, silver, and gold)-are reported with the aim of exploring the metal-dependent nature of surface-chemisorbate interactions. The Pt-group surfaces were prepared as ultrathin electrodeposited films on gold, enabling the SERS activity inherent to the substrate to be imparted to the overlayer material. Benzonitrile was selected as a "model" organic adsorbate since it displays a rich array of coupled aromatic ring as well as substituent modes which collectively can provide insight into the various molecular perturbations induced by surface coordination via the nitrile substituent. The experimental spectra are compared with ab initio calculations of vibrational frequencies, bond geometries, and charge distributions obtained by means of Density Functional Theory (DFT), which yields valuable insight into the underlying structural reasons for the sensitivity of the experimental coordination-induced frequency shifts to the nature of the intramolecular mode and the metal surface. The DFT results also form an invaluable aid in making SER spectral assignments, along with providing detailed information on the coupled atomic displacements involved in each vibrational mode. Benzonitrile surface coordination was modeled in the DFT calculations by binding the nitrile group to metal atoms and small metal clusters. While the majority of the aromatic-ring SER frequencies are altered only slightly (approximately < 5 cm(-1)) upon surface coordination, several modes (especially nu(1), nu(6a)) are blue-shifted substantially (by up to 50 cm(-1)). These shifts were identified by DFT as arising from mode coupling to the nitrile substituent, especially involving the C-CN bond that is compressed upon nitrile coordination, associated with metal-adsorbate back-donation. The small (<5 cm(-1)) red-shifts seen for ring vibrations not involving coupled substituent motion apparently arise from increased antibonding aromatic electron density. The metal-dependent frequency shifts seen for these coupled aromatic vibrations as well as for the more localized C-N nitrile stretching mode are consistent with increased back-donation anticipated in the sequence d(10) < d(9) < d(8) within a given Periodic row. Overall, the findings provide a benchmark illustration of the virtues of DFT in interpreting complex vibrational spectra for larger polyatomic adsorbates.

Surface-enhanced Raman scattering on uniform platinum-group overlayers: preparation by redox replacement of underpotential-deposited metals on gold.

The preparation of Pt-group metal films on roughened gold electrodes by utilizing spontaneous redox replacement of an underpotential-deposited (upd) copper or lead monolayer with a Pt-group metal cation solute is described. The resulting films display intense surface-enhanced Raman scattering (SERS) for adsorbates bound to the overlayer and free from substrate interferences. This strategy provides a useful alternative, at least for platinum, to the constant-current electrodeposition method commonly utilized to prepare SERS-active Pt-group metal films (Zou, S.; Weaver, M. J. Anal. Chem. 1988, 70. 2387). Similarly to related earlier studies, the film uniformity (specifically, the absence or otherwise of residual Au "pinhole" sites) was tested by employing carbon monoxide, and also ethylene, as "probe" chemisorbates, since they yield vibrational frequencies on Au that are blue-shifted from the corresponding bands for adsorbate bound to Pt-group metal sites. While a single redox replacement of upd Cu with Pt(IV) yielded incomplete surface coverage, as expected, the use of multiple (up to eight) replacement cycles produced Pt films displaying remarkably intense CO vibrational bands as well as apparently "pinhole-free" properties, although such imperfections were detected with the ethylene probe. A single upd Cu replacement with Pt(II), however, yielded a remarkably uniform Pt layer, as indicated by pinhole-free characteristics using both the CO and ethylene probes along with the voltammetric behavior. The use of additional redox replacement cycles yielded marked progressive attenuation in the SERS signals. Comparable, although less optimal, SERS behavior was obtained for Pd films prepared similarly from Pd(II). The value of the strategy for exploring catalytic as well as equilibrium adsorptive chemistry on Pt surfaces is also illustrated.

Synergistic hepatocarcinogenic effect of hepadnaviral infection and dietary aflatoxin B1 in woodchucks.

Interactive hepadnaviral and chemical hepatocarcinogenesis was studied in woodchucks inoculated as newborns with woodchuck hepatitis virus (WHV), which is closely related to the human hepatitis B virus. When the woodchucks reached 12 months of age, aflatoxin B1 (AFB1) was administered in the diet at dose levels of 40 micrograms/kg body weight/day for 4 months and subsequently 20 micrograms/kg body weight/day (5 days/week) for lifetime. WHV DNA was demonstrated by Southern blot hybridization in the serum and by PCR in the serum and/or liver tissue. The histo- and cytomorphology of the liver were investigated by light and electron microscopy. WHV carriers with and without AFB1 treatment developed a high incidence of preneoplastic foci of altered hepatocytes, hepatocellular adenomas, and hepatocellular carcinomas that appeared 6-26 months after the beginning of the combination experiment. Administration of AFB1 to WHV carriers resulted in a significantly earlier appearance of hepatocellular neoplasms and a higher incidence of hepatocellular carcinomas compared to WHV carriers not treated with AFB1. Neither hepatocellular adenomas nor carcinomas (but preneoplastic foci of altered hepatocytes) were detected in woodchucks receiving AFB1 alone, and no preneoplastic or neoplastic lesions were found in untreated controls. These results provide conclusive evidence of a synergistic hepatocarcinogenic effect of hepadnaviral infection and dietary AFB1. Except for the frequent presence of ground glass cells containing surface antigen filaments in the infected woodchucks, the phenotype of preneoplastic foci of altered hepatocytes was similar in WHV carriers with and without exposure to AFB1 and in animals treated with AFB1 alone. Clear cell foci excessively storing glycogen and/or fat, amphophilic cell foci crowded with mitochondria and peroxisomes, and mixed cell foci composed of various cell types including basophilic cells rich in ribosomes predominated. The cellular phenotype in neoplastic lesions varied from clear, amphophilic, and mixed cell populations in highly differentiated adenomas and carcinomas to basophilic cell populations prevailing in poorly differentiated carcinomas. The striking similarities in altered cellular phenotypes of preneoplastic hepatic foci emerging after both hepadnaviral infection and exposure to AFB1 suggest closely related underlying molecular mechanisms that may be mainly responsible for the synergistic hepatocarcinogenic effect of these oncogenic agents.

Microchip implant system used for animal identification in laboratory rabbits, guineapigs, woodchucks and in amphibians.

Traditional methods for animal identification have a number of drawbacks. We evaluated a new system for individual identification using microchip implants in rabbits, guineapigs, woodchucks (Marmota monax) and amphibians (Xenopus laevis, Pleurodeles waltlii). Implantation procedure and long-term observations are described. Microchip implants proved to be a practicable and reliable system for animal identification without obvious adverse effects. The applicability of electronic animal identification in comparison with common methods and with regard to animal welfare and legal aspects is discussed.

Efficiency of air filter sets for the prevention of airborne infections in laboratory animal houses.

Air filter sets (classes EU6 and EU9, or EU6 and S) were tested for their efficiency in protecting laboratory animals against potential airborne infections. Flexible-film isolators were used as a smaller scale model. In the first experiment, lasting 7 months, it was tested whether minute virus of mice (MVM) was able to penetrate the air filters between one isolator containing experimentally infected mice and another with MVM negative mice. In the second experiment we tested whether microorganisms in the incoming air were able to penetrate air filter sets. To assess this gnotobiotic mice in an isolator were monitored for 9 months for changes of their microbial flora. In both experiments a combination of EU6 and EU9 air filters proved to be sufficient to maintain the microbiological status of the animals. The same combination of medium efficiency filters (EU6 and EU9) is used on the air supply to 4 SPF-barrier units in which infections with MVM occurred repeatedly soon after the initial stocking. After a thorough disinfection no reinfection has been detected to date. This demonstrates that the relatively low efficiency of the air filters was not the cause of the repeated infection. The procedure for disinfection is described.

[Intestinal Chlamydia psittaci infection of cattle: frequency and technical aspects of the cultural detection of the agent]. / Die intestinale Chlamydia psittaci-Infektion des Rindes: Häufigkeit sowie technische Aspekte des kulturellen Erregernachweises.

With the purpose to evaluate the prevalence of latent chlamydial infections in cattle, 190 animals were examined for fecal shedding of chlamydiae. From the feces of 42 animals (22.1%) Chlamydia (C.) psittaci was grown either in the yolk sac of chicken embryos and/or in coverslip cultures of BGM-cells. The cell culture proved to be of lower susceptibility to chlamydial infections. In comparison with the chicken egg technique a sixfold quantity of chlamydial particles was required to initiate detectable intracellular growth. With the chicken embryo technique as a standard cell culture with a sensitivity range of 31.6% was not satisfactory for isolating chlamydiae from bovine feces. Attempts to recover chlamydiae from feces of two experimentally infected heifers in embryonated chicken eggs provided evidence that at least four randomly subsequent isolation trials are required to detect asymptomatic chlamydial infections of the bovine gut with a 95% confident level. Based on this fact, the positivity rate of 22.1% obtained by single fecal specimen examination indicates a wide spread occurrence of chlamydial infections in cattle.