Biological Trojan horse: Antigen 43 provides specific bacterial uptake and survival in human neutrophils

Escherichia coli is a versatile pathogen causing millions of infections in humans every year. This bacterium can form multicellular aggregates when it expresses a self-associating protein, antigen 43 (Ag43), on its surface. We have discovered that Ag43-expressing E. coli cells are efficiently taken up by human defense cells, polymorphonuclear neutrophils (PMNs), in an opsonin-independent manner. Surprisingly, the phagocytosed bacteria were not immediately killed but resided as tight aggregates within the PMNs. Our observations indicate that Ag43-mediated uptake and survival in PMNs constitute a mechanism to subvert one of the primary defense mechanisms of the human body.     

Efficacy of high-level microwave disinfection of dental gypsum casts: the effects of number and weight of casts

The aim of this study was to determine if the bactericidal effect of microwaving gypsum casts is maintained at maximum capacity of the oven (16 casts). Batches of 8 and 16 gypsum casts made from in vivo impressions were divided in half. One half of each cast was microwaved at 900 W for 5 minutes. The remaining halves were left untreated. When assessed for bacteriological growth, the median cfu/mL of the untreated casts was between 10(5) and 10(6) [corrected] while the microwaved casts showed a cfu/mL of 0, indicating that microwaving as described will disinfect gypsum casts even at maximum capacity of the oven.     

Perceptions of patients' smiles: a comparison of patients' and dentists' opinions

BACKGROUND: Little information has been published regarding the difference between how patients perceive their own smiles and how dentists view them. METHODOLOGY: The authors interviewed 78 consecutively seen patients in a general dental practice in Norway about esthetic features of their faces. The patients were not actively seeking esthetic treatment. Patients rated themselves using a 100-point visual analog scale (VAS), and then two dentists (the patients' regular dentist and an independent periodontist), working with photographs of the patients, used the same VAS in rating the patients' smiles. RESULTS: The average age of the patients was 51.2 years (range, 22-84 years). There were 50 women (average age, 51.5 years; range, 22-84 years) and 28 men (average age, 52 years; range, 30-78 years). Patients' satisfaction with their own smiles reached an average of 59.1 (standard deviation [SD], 21.1; range, 5-100) on the VAS. The dentists' scores (38.6 and 40.7) were significantly lower than the patients' scores. The authors observed poor correlation between the periodontist's scores of dentogingival features and the patients' scores. Patients were most satisfied with the gingiva when smiling and least satisfied with tooth shade. Patients younger than 50 years were most satisfied with their smiles. Patients rated teeth and eyes as the most important features in an attractive face. Women gave teeth and hair significantly higher scores and head shape lower scores than did men. CONCLUSION: Patients' opinions of their own smiles were significantly higher than the two clinicians' assessments of their smiles. Dentists should be aware that patients who seek esthetic services may have different perceptions of their smiles than may patients who do not express such desires.     

Acute Toxicity of Eight Oil Spill Response Chemicals to Temperate,Boreal, and Arctic Species

The objectives of this study were to (1) determine the acute toxicity of selected shoreline washing agents (SWA) and dispersants, and (2) assess interspecies differences in sensitivity to the products. Eight shoreline washing agents (Hela saneringsvæske, Bios, Bioversal, Absorrep K212, and Corexit 9580) and chemical dispersants (Corexit 9500, Dasic NS, and Gamlen OD4000) were tested on five marine species, algae Skeletonema costatum, planktonic copepod species Acartia tonsa (temperate species), Calanus finmarchicus (boreal species) and Calanus glacialis (Arctic species), and benthic amphipod Corophium volutator. For most products, A. tonsa was the most sensitive species, whereas C. volutator was the least sensitive; however, these species were exposed through different media (water/sediment). In general, all copepod species displayed a relatively similar sensitivity to all products. However, A. tonsa was somewhat more sensitive than other copepods to most of the tested products. Thus, A. tonsa appears to be a candidate species for boreal and Arctic copepods for acute toxicity testing, and data generated on this species may be used as to provide conservative estimates. The benthic species (C. volutator) had a different sensitivity pattern relative to pelagic species, displaying higher sensitivity to solvent-based SWA than to water-based SWA. Comparing product toxicity, the dispersants were in general most toxic while the solvent-based SWA were least toxic to pelagic species.     

Modulation of Intestinal Inflammation by Minimal Enteral Nutrition With Amniotic Fluid in Preterm Pigs

Background: Necrotizing enterocolitis (NEC) is a severe inflammatory disorder, associated with the difficult transition from parenteral to enteral feeding after preterm birth. We hypothesized that minimal enteral nutrition (MEN) with amniotic fluid (AF), prior to enteral formula feeding, would improve resistance to NEC in preterm pigs. Methods: Experiment 1: IEC‐6 cells were incubated with porcine (pAF) and human AF (hAF) to test AF‐stimulated enterocyte proliferation and migration in vitro. Experiment 2: Cesarean‐delivered, preterm pigs were fed parenteral nutrition and MEN with pAF, hAF, or control fluid (MEN‐pAF, MEN‐hAF, or MEN‐CTRL; all n = 9) for 2 days before tissue collection. Experiment 3: Preterm pigs were fed MEN diets as in experiment 2, but followed by 2 days of enteral formula feeding, which predisposes to NEC (NEC‐pAF, NEC‐hAF, or NEC‐CTRL; n = 10–12). Results: Both pAF and hAF stimulated enterocyte proliferation and migration in vitro. In experiment 2, MEN‐pAF and MEN‐hAF pigs showed increased body weight gain and reduced intestinal interleukin (IL)–8 and colonic IL‐6 levels, indicating reduced inflammatory response. In experiment 3, body weight gain was highest in the 2 groups fed AF as MEN, but NEC incidences were similar (NEC‐pAF) or increased (NEC‐hAF) compared with controls. Conclusions: Intake of pAF or hAF improved body growth and modulated intestinal inflammatory cytokines during a period of parenteral nutrition, but did not protect against later formula‐induced NEC in preterm pigs. Further studies are required to show if MEN feeding with species‐specific AF, combined with an optimal enteral diet (eg, human milk), will improve adaptation during the transition from parenteral to enteral feeding in preterm neonates.