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Distribution by Scientific Domains

Selected Abstracts

Local inflammatory response in choriodecidua induced by Ureaplasma urealyticum

R Aaltonen
Ureaplasma urealyticum is the bacterial species most often connected with preterm birth, although it often colonises the amniotic fluid without any adverse effects. The induction of preterm labour seems to depend on whether the bacteria produce an inflammatory reaction. In vitro stimulation of choriodecidual tissue with high amounts of U.urealyticum or with lipopolysaccharide induced a qualitatively similar inflammatory response detected by the production of tumour necrosis factor alpha, followed by secretion of anti-inflammatory cytokine interleukin-10 and of prostaglandin E2. Lower quantities of bacteria failed to induce any response. [source]

Minimizing the release of proinflammatory and toxic bacterial products within the host: A promising approach to improve outcome in life-threatening infections

Roland Nau
Abstract Various bacterial components (e.g., endotoxin, teichoic and lipoteichoic acids, peptidoglycans, DNA) induce or enhance inflammation by stimulating the innate immune system and/or are directly toxic in eukariotic cells (e.g., hemolysins). When antibiotics which inhibit bacterial protein synthesis kill bacteria, smaller quantities of proinflammatory or toxic compounds are released in vitro and in vivo than during killing of bacteria by ,-lactams and other cell-wall active drugs. In general, high antibiotic concentrations liberate lower quantities of bacterial proinflammatory or toxic compounds than concentrations close to the minimum inhibitory concentration. In animal models of Escherichia coli Pseudomonas aeruginosa and Staphylococcus aureus peritonitis/sepsis and of Streptococcus pneumoniae meningitis, a lower release of proinflammatory bacterial compounds was associated with a reduced mortality or neuronal injury. Pre-treatment with a bacterial protein synthesis inhibitor reduced the strong release of bacterial products usually observed during treatment with a ,-lactam antibiotic. Data available strongly encourage clinical trials comparing antibiotic regimens with different release of proinflammatory/toxic bacterial products. The benefit of the approach to reduce the liberation of bacterial products should be greatest in patients with a high bacterial load. [source]

A multifaceted imbalance of T cells with regulatory function characterizes type 1 autoimmune hepatitis,,

HEPATOLOGY, Issue 3 2010
Silvia Ferri
Immunotolerance is maintained by regulatory T cells (Tregs), including CD4+CD25hi, CD8+CD28,, ,,, and CD3+CD56+ [natural killer T (NKT)] cells. CD4+CD25hi cells are impaired in children with autoimmune hepatitis (AIH). Little is known about Tregs in adults with AIH. The aim of this study was to investigate the frequency and function of Treg subsets in adult patients with AIH during periods of active disease and remission. Forty-seven AIH patients (16 with active disease and 31 in remission) and 28 healthy controls were studied. Flow cytometry was used to evaluate surface markers and function-related intracellular molecules in ,,, CD8+CD28,, NKT, and CD4+CD25hi cells. CD4+CD25hi T cell function was determined by the ability to suppress proliferation and interferon gamma (IFN-,) production by CD4+CD25, target cells. Liver forkhead box P3,positive (FOXP3+) cells were sought by immunohistochemistry. In AIH patients, particularly during active disease, CD4+CD25hi T cells were fewer, expressed lower levels of FOXP3, and were less effective at inhibiting target cell proliferation versus healthy controls. Moreover, although the numbers of CD8+CD28, T cells were similar in AIH patients and healthy controls, NKT cells were numerically reduced, especially during active disease, and produced lower quantities of the immunoregulatory cytokine interleukin-4 versus controls. In contrast, ,, T cells in AIH patients were more numerous versus healthy controls and had an inverted V,1/V,2 ratio and higher IFN-, and granzyme B production; the latter was correlated to biochemical indices of liver damage. There were few FOXP3+ cells within the portal tract inflammatory infiltrate. Conclusion: Our data show that the defect in immunoregulation in adult AIH is complex, and ,, T cells are likely to be effectors of liver damage. (HEPATOLOGY 2010) [source]

Promiscuous Substrate Binding Explains the Enzymatic Stereo- and Regiocontrolled Synthesis of Enantiopure Hydroxy Ketones and Diols

Marcela Kurina-Sanz
Abstract Regio- and stereoselective reductions of several diketones to afford enantiopure hydroxy ketones or diols were accomplished using isolated alcohol dehydrogenases (ADHs). Results could be rationalised taking into account different (promiscuous) substrate-binding modes in the active site of the enzyme. Furthermore, interesting natural cyclic diketones were also reduced with high regio- and stereoselectivity. Some of the 1,2- and 1,3-diketones used in this study were reduced by employing a low excess of the hydrogen donor (2-propanol) due to the quasi-irreversibility of these ADH-catalysed processes. Thus, using lower quantities of co-substrate, scale-up could be easily achieved. [source]

Eating between the Lines: Mississippian Migration and Stable Carbon Isotope Variation in Fort Ancient Populations

Robert A. Cook
ABSTRACT Appreciating variation along the edges of traditional archaeological Culture Historical boundaries requires close consideration of social contexts associated with culture contact. We focus on dietary variation as a function of these concerns through a case study of Fort Ancient populations who, on average, consumed lower quantities of maize than their Mississippian neighbors as determined by stable carbon isotope ratios of bone collagen. However, this dichotomy is not as rigid as initially thought, with some Fort Ancient burials producing stable carbon isotope ratios similar to Mississippian cases. Detailed investigation of internal variation of carbon isotopes for human burials at the SunWatch site provides evidence that contact included small-scale Mississippian migrations to Fort Ancient sites. The main conclusion is that variation in diet and archaeological context can be a useful approach for examining prehistoric migration. [source]

Lower levels of plasmacytoid dendritic cells in peripheral blood are associated with a diagnosis of asthma 6 yr after severe respiratory syncytial virus bronchiolitis

Eli Silver
Plasmacytoid dendritic cells (pDC) play a crucial role in antiviral immunity and promoting Th1 polarization, possibly protecting against development of allergic disease. Examination of the relationship between peripheral blood plasmacytoid DC levels and manifestations of asthma and atopy early in life. We have isolated peripheral blood mononuclear cells (PBMC) from 73 children (mean age SD: 6.6 0.5 yr old) participating in the RSV Bronchiolitis in Early Life (RBEL) study. Flow cytometry was performed on PBMC detecting DC surface-markers: Blood Dendritic Cell Antigens (BDCA) 1, 3, and 2 which identify myeloid type 1, type 2, and plasmacytoid cells, respectively. Total serum IgE, peripheral eosinophil count, and allergy skin tests were documented. About 45% (n = 33) of study participants had physician-diagnosed asthma by 6 yr of age. These children had significantly lower quantities (mean SD) of plasmacytoid DC than their non-asthmatic counterparts (1020 921 vs. 1952 1170 cells per 106 PBMC, p = 0.003). We found significantly lower numbers of myeloid dendritic cells in children with asthma (3836 2472 cells per 106 PBMC) compared with those without asthma (4768 2224 cells per 106 PBMC, p = 0.02); however, this divergence was not significant after adjusting for covariates of age, gender, race, skin test reactivity, smoke exposure, and daycare attendance. We did not identify any direct association between DC levels and markers of atopy: skin test reactivity, peripheral eosinophilia, and IgE level. Children who are diagnosed with asthma after severe RSV bronchiolitis appear to have a relative deficiency of plasmacytoid DC in peripheral blood. [source]

A Morphological and 13C NMR Study of the Extramandibular Fat Bodies of the Striped Dolphin (Stenella coeruleoalba)

C. Maxia
Abstract The molecular and histological structure of the fat bodies covering externally the posterolateral region of the jaw of the striped dolphin (Stenella coeruleoalba) was investigated by means of morphological and nuclear magnetic resonance techniques. The analyses of samples belonging to adult and juvenile individuals were performed with the aim of seeking the presence of age-related differences. In our study, the level of isovalerate (iso5:0) in the extramandibular fat of the juvenile individuals is comparable with those of the adult counterparts; conversely, longer isobranched fatty acids were detected in lower quantities in the juveniles together with a higher degree of unsaturation. The morphologic analyses revealed that, in both adults and juveniles, this fatty tissue is similar to univacuolar adipose tissue. However, in the juveniles, a muscular component was present, whereas only in adult subjects, enlarged and irregularly shaped cavities may be seen within the adipose tissue. These cavities, structurally organized as veins, may regulate blood flow in response to changing water temperature and stabilize thermal gradient within the jaw lipids. These data suggest that the molecular components and the histological organization can indicate a maturation of the organ with age that probably may reflect different sound reception properties. Anat Rec, 2007. 2007 Wiley-Liss, Inc. [source]

Novel Rice-shaped Bioactive Ceramic Nanoparticles (Adv. Eng.

The cover of Advanced Biomaterials shows Rice-shaped bioactive ceramic nanoparticles with 70 nm in average diameter and around 200 nm in length were produced by an improved sol-gel method. In comparison to most traditional bioactive glass/ceramic materials this novel bioactive ceramic contains a significant lower quantity of silicon and higher content of phosphorous. In vitro bioactivity test showed that this new class of materials can induce the deposition of an apatite layer from SBF solution, having potential to be used in both conventional orthopedic applications or in bone tissue engineering when incorporated in composite scaffolds. More information can be found in the article of J. F. Mano et al. on page B25. [source]

Novel Rice-shaped Bioactive Ceramic Nanoparticles,

Zhongkui Hong
Rice-shaped bioactive ceramic nanoparticles of 70 nm average diameter and around 200 nm length were produced by an improved sol-gel method. In comparison to most traditional bioactive glass/ceramic materials, this novel bioactive ceramic contains a significant lower quantity of silicon and higher content of phosphorous. In vitro bioactivity tests showed that this new class of materials can induce the deposition of an apatite layer from simulated body fluid, having the potential to be used in both conventional orthopedic applications or in bone tissue engineering when incorporated in composite scaffolds. [source]

Composition and antimicrobial activity of essential oil of Stachys plumosa Griseb.

Silvana Petrovi
Abstract The essential oil of Balkan endemic Stachys plumosa Griseb. obtained by steam distillation was analysed by GC and GC,MS. Essential oil yield was 0.15% (v/w) and 45 components were identified (86.9% of the total amount). Dehydroabietane was identified as the most prominent component (61.2%), while other constituents were present in much lower quantity, predominantly diterpenes kaurene and biformene (3.2% and 3.0%, respectively). The antimicrobial activity was tested on six bacterial strains and two fungal strains, using the agar diffusion method. Diameters of growth inhibition zones were measured. The most sensitive microorganisms were, in order: Pseudomonas aeruginosa > Bacillus subtilis > Enterococcus faecalis > Klebsiella pneumoniae > Candida albicans (ATCC 10259) > Candida albicans (ATCC 24433) > Escherichia coli > Staphylococcus aureus. Copyright 2005 John Wiley & Sons, Ltd. [source]

Impacts of differential consumption by the grazing fish, Plecoglossus altivelis, on the benthic algal composition in the Chikuma River, Japan

Shin-ichiro Abe
SUMMARY Grazing effects of ayu, Plecoglossus altivelis Temminck et Schegel, on the benthic algal assemblages were investigated in the Chikuma River, Japan. Comparison of the algal composition on boulders with and without intensively grazed patches indicated that fish grazing decreased the abundance of diatoms and prostrate filamentous cyanobacteria and caused upright filamentous cyanobacteria to predominate. Differential consumption by ayu was estimated by comparing the relative abundance of algae in the stomach contents of ayu and that in the algal assemblages within the grazed patches. The results showed that ayu consumed the prostrate filamentous cyanobacteria proportionally to their abundance, whereas they ingested diatoms and the upright filamentous cyanobacteria in a larger and lower quantity, respectively, than that expected from their abundance. Differential consumption would involve the change in the algal composition toward the predominance of upright filamentous cyanobacteria under fish grazing conditions. [source]

Increased aggregation propensity of IgG2 subclass over IgG1: Role of conformational changes and covalent character in isolated aggregates

Heather Franey
Abstract Aggregation of human therapeutic antibodies represents a significant hurdle to product development. In a test across multiple antibodies, it was observed that IgG1 antibodies aggregated less, on average, than IgG2 antibodies under physiological pH and mildly elevated temperature. This phenomenon was also observed for IgG1 and IgG2 subclasses of anti-streptavidin, which shared 95% sequence identity but varied in interchain disulfide connectivity. To investigate the structural and covalent changes associated with greater aggregation in IgG2 subclasses, soluble aggregates from the two forms of anti-streptavidin were isolated and characterized. Sedimentation velocity analytical ultracentrifugation (SV-AUC) measurements confirmed that the aggregates were present in solution, and revealed that the IgG1 aggregate was composed of a predominant species, whereas the IgG2 aggregate was heterogeneous. Tertiary structural changes accompanied antibody aggregation as evidenced by greater ANS (8-Anilino-1-naphthalene sulfonic acid) binding to the aggregates over monomer, and differences in disulfide character and tryptophan environments between monomer, oligomer and aggregate species, as observed by near-UV circular dichroism (CD). Differences between subclasses were observed in the secondary structural changes that accompanied aggregation, particularly in the intermolecular ,-sheet and turn structures between the monomer and aggregate species. Free thiol determination showed ,2.4-fold lower quantity of free cysteines in the IgG1 subclass, consistent with the 2.4-fold reduction in aggregation of the IgG1 form when compared with IgG2 under these conditions. These observations suggested an important role for disulfide bond formation, as well as secondary and tertiary structural transitions, during antibody aggregation. Such degradations may be minimized using appropriate formulation conditions. [source]