Localization of99mTc in bone by means of autoradiography

The uptake of two different preparations of^99mTechnetium-methylene diphosphonate in fetal rat calvaria is compared. The localization of^99mTc after administration of^99mTc(Sn)-MDP and^99mTc-MDP showed equal distribution in autoradiography.     

Detection of Helicobacter species DNA by quantitative PCR in the gastrointestinal tract of healthy individuals and of patients with inflammatory bowel disease

In many animal species different intestinal Helicobacter species have been described and a few species are associated with intestinal infection. In humans, the only member of the Helicobacter family which is well described in literature is Helicobacter pylori. No other Helicobacter-associated diseases have definitely been shown in humans. We developed a sensitive quantitative PCR to investigate whether Helicobacter species DNA can be detected in the human gastrointestinal tract. We tested gastric biopsies (including biopsies from H. pylori positive persons), intestinal mucosal biopsies and fecal samples from healthy persons, and intestinal mucosal biopsies from patients with inflammatory bowel disease (IBD) for the presence of Helicobacter species. All gastric biopsies, positive for H. pylori by culture, were also positive in our newly developed PCR. No Helicobacter species were found in the mucosal biopsies from patients with IBD (n = 50) nor from healthy controls (n = 25). All fecal samples were negative. Our study suggests that Helicobacter species, other than H. pylori, are not present in the normal human gastrointestinal flora and our results do not support a role of Helicobacter species in IBD.     

Interactions ofCandida albicans with bacteria and salivary molecules in oral biofilms

The yeastCandida albicans coaggregates with a variety of streptococcal species, an interaction that may promote oral colonization by yeast cells.C. albicans andCandida tropicalis are the yeasts most frequently isolated from the human oral cavity and our data demonstrate that both these species bind toStreptococcus gordonii NCTC 7869 while two otherCandida species (Candida krusei andCandida kefyr) do not. Adherence ofC. albicans was greatest when the yeast had been grown at 30° C to mid-exponential growth phase. For 21 strains ofC. albicans there was a positive correlation between the ability to adhere toS. gordonii and adherence to experimental salivary pellicle. Whole saliva either stimulated or slightly inhibited adherence ofC. albicans toS. gordonii depending on the streptococcal growth conditions. The results suggest that the major salivary adhesins and coaggregation adhesins ofC. albicans are co-expressed.     

Development of an internally controlled PCR assay for broad range detection of bacteria in platelet concentrates

A real-time PCR assay based on the 16S rRNA gene was optimized for the detection of a broad range of bacteria in plasma and platelet concentrates (PC). A lambda phage internal control was constructed and implemented in the assay, which made it suitable for diagnostic use. Spiking studies in plasma and PCs were performed to determine the analytical sensitivity of the assay. Thirty three colony forming units (CFU)/ml of E. coli and 72 CFU/ml of Staphylococcus epidermidis could be detected in plasma, and 97 CFU/ml of S. epidermidis in PCs. The assay detected all bacteria relevant for bacterial contamination of PCs. The short turn around time of the assay made it suitable for testing PCs for bacterial contamination prior to transfusion.     

The Effect of IFN-gamma, Alum and Complete Freund Adjuvant on TNP-KLH Induced Ig.G(1), IgE and IgG(2a) Responses in Mice

Adjuvants are considered to play an important role in directing the isotype and amount of antibodies produced upon immunization by conducting the development of either Th-1 or Th-2 cells upon T-cell stimulation. This is based on the different cytokine production patterns that were observed after in vitro resttmulation of T cells isolated from mice immunized with antigen either adsorbed on alum or emulsified in complete Freund adjuvant (CFA). However, other studies suggest that primarily the type of antigen determines which isotypes are produced and to what extent. In these studies, however, IgE was not determined. Therefore, this study examined whether alum and CFA influenced the amount and/or ratio of IgG(1), IgE and IgG(2a) produced after TNP-KLH immunization. Similar levels of IgG(1), IgE and IgG(2a) antibodies were found upon immunization with TNP-KLH either adsorbed on alum or emulsified in CFA. Moreover, administration of IFN-gamma in combination with TNP-KLH adsorbed on alum did not increase the amount of IgG(2a) produced. IFN-gamma treatment resulted in an increased IL-6 and decreased IFN-gamma production by spleen cells upon Con A stimulation, whereas it did not change the IL-4 production in similar conditions. The presented results suggest that upon immunization with TNP-KLH high IL-4 levels are produced, resulting in an antibody response that is dominated by IgG(1), independent of the adjuvant employed. The IL-4 inducing property of TNP-KLH is substantiated by the finding that repeated immunization of mice with TNP-KI, without adjuvant, increases the serum total IgE level. The presented data suggest that the carrier part of TNP-KLH preferentially results in Th-2 cell activity after which the adjuvant merely enhances the antibody responses generated.     

Haemocyte reactions in WSSV immersion infected Penaeus monodon

White spot syndrome virus (WSSV) has been a major cause of shrimp mortality in aquaculture worldwide in the past decades. In this study, WSSV infection (by immersion) and behaviour recruitment of haemocytes is investigated in gills and midgut, using an antiserum against the viral protein VP28 and a monoclonal antibody recognising haemocytes (WSH8) in a double immunohistochemical staining and in addition transmission electron microscopy was applied. More WSH 8(+) haemocytes were detected at 48 and 72 h post-infection in the gills of infected shrimp compared to uninfected animals. Haemocytes in the gills and midgut were not associated with VP28-immunoreactivity. In the gills many other cells showed virus replication in their nuclei, while infected nuclei in the gut cells were rare. Nevertheless, the epithelial cells in the midgut showed a clear uptake of VP28 and accumulation in supranuclear vacuoles (SNV) at 8h post-infection. However, epithelial nuclei were never VP28-immunoreactive and electron microscopy study suggests degradation of viral-like particles in the SNV. In contrast to the gills, the midgut connective tissue shows a clear increase in degranulation of haemocytes, resulting in the appearance of WSH8-immunoreactive thread-like material at 48 and 72 h post-infection. These results indicate recruitment of haemocytes upon immersion infection in the gills and degranulation of haemocytes in less infected organs, like the midgut.