Identifying fermenting bacteria in anoxic tidal-flat sediments by a combination of microcalorimetry and ribosome-based stable-isotope probing

A novel approach was developed to follow the successive utilization of organic carbon under anoxic conditions by microcalorimetry, chemical analyses of fermentation products and stable-isotope probing (SIP). The fermentation of (13) C-labeled glucose was monitored over 4 weeks by microcalorimetry in a stimulation experiment with tidal-flat sediments. Based on characteristic heat production phases, time points were selected for quantifying fermentation products and identifying substrate-assimilating bacteria by the isolation of intact ribosomes prior to rRNA-SIP. The preisolation of ribosomes resulted in rRNA with an excellent quality. Glucose was completely consumed within 2 days and was mainly fermented to acetate. Ethanol, formate, and hydrogen were detected intermittently. The amount of propionate that was built within the first 3 days stayed constant. Ribosome-based SIP of fully labeled and unlabeled rRNA was used for fingerprinting the glucose-degrading species and the inactive background community. The most abundant actively degrading bacterium was related to Psychromonas macrocephali (similarity 99%) as identified by DGGE and sequencing. The disappearance of Desulfovibrio-related bands in labeled rRNA after 3 days indicated that this group was active during the first degradation phase only. In summary, ribosome-based SIP in combination with microcalorimetry allows dissecting distinct phases in substrate turnover in a very sensitive manner.     

Borderline typical symptoms in adult patients with attention deficit/hyperactivity disorder

Adult attention deficit/hyperactivity disorder (ADHD) and borderline personality disorder (BPD) share several clinical features, e.g. emotional lability and impulsivity. This study aimed to delineate differences and similarities between ADHD and BPD with respect to borderline typical symptomatology and gender specifics. Borderline symptomatology was assessed in 60 adult patients with ADHD with the borderline symptom list (BSL) and compared to both 60 gender- and age-matched BPD patients and control subjects. The BSL is a standardized instrument including 95 items on 7 subscales (self-perception, affect regulation, self-destruction, dysphoria, loneliness, intrusions and hostility). Adult ADHD patients showed significantly higher BSL total scores and all of the seven subscales compared to healthy controls (p < 0.001) but lower scores than BPD patients (p < 0.001). With respect to the seven subscales, the largest differences between ADHD and BPD patients were found with respect to self-destruction (d = 1.12) and affect dysregulation (d = 0.90), whereas the smallest difference was found with respect to loneliness (d = 0.36). In females, the BSL subscales "loneliness" and "hostility" did not differentiate between BPD and ADHD. Borderline typical symptoms are common in adult patients with ADHD but seem to be less pronounced than in patients with BPD. Females with ADHD and BPD share more clinical features than males. However, symptoms of self-destruction and affect dysregulation appear to be more severe in BPD patients.     

Endogenous dendritic cells are required for amplification of T cell responses induced by dendritic cell vaccines in vivo

Dendritic cells (DCs) loaded in vitro with Ag are used as cellular vaccines to induce Ag-specific immunity. These cells are thought to be responsible for direct stimulation of Ag-specific T cells, which may subsequently mediate immunity. In this study, in transgenic mouse models with targeted MHC class II expression specifically on DCs, we show that the DC vaccine is responsible only for partial CD4(+) T cell activation, but to obtain optimal expansion of T cells in vivo, participation of endogenous (resident) DCs, but not endogenous B cells, is crucial. Transfer of Ag to endogenous DCs seems not to be mediated by simple peptide diffusion, but rather by DC-DC interaction in lymph nodes as demonstrated by histological analysis. In contrast, injection of apoptotic or necrotic DC vaccines does not induce T cell responses, but rather represents an immunological null event, which argues that viability of DC vaccines can be crucial for initial triggering of T cells. We propose that viable DCs from the DC vaccine must migrate to the draining lymph nodes and initiate a T cell response, which thereafter requires endogenous DCs that present transferred Ag in order induce optimal T cell expansion. These results are of specific importance with regard to the applicability of DC vaccinations in tumor patients, where the function of endogenous DCs is suppressed by either tumors or chemotherapy.