Biofilm formation and adhesive/invasive properties of <Emphasis Type="Italic">Candida dubliniensis</Emphasis> in comparison with <Emphasis Type="Italic">Candida albicans</Emphasis>

Candida dubliniensis and Candida albicans are closely related spp. exhibiting differences in their virulence potency. This study compared clinical isolates of C. dubliniensis with C. albicans from HIV patients with oropharyngeal candidiasis (OPC) and standard strains in power to form biofilm and their adhesive and invasive properties. Members of both spp. were able to form strong biofilms. However, SEM microscopy confirmed that C. albicans undergoes the more effective yeast-to-hyphae transition than C. dubliniensis with prevalent yeast form and limited ability to form filaments. Kinetic patterns indicated that while the first 30 min are critical for sufficient attachment to a polystyrene surface, adhesion to human carcinoma cell lines (Caco-2 and TR 146) needs additional time with maximal saturation observed at 240 min for both spp. The invasion process was tested on 3D RHE (reconstituted human epithelium) with Caco-2 or TR 146 on the collagen surface. C. albicans rapidly produced hyphae that penetrated the tissue layer, demonstrating substantive invasion within 21 h. In contrast, C. dubliniensis attached to the tissue surface and proliferated, suggesting the formation of a biofilm-like structure. After 21 h, C. dubliniensis was able to penetrate the RHE layer and invade unusually, with a cluster of the yeast cells.     

Trend in obesity prevalence in European adult cohort populations during follow-up since 1996 and their predictions to 2015

Objective

To investigate trends in obesity prevalence in recent years and to predict the obesity prevalence in 2015 in European populations.

Methods

Data of 97 942 participants from seven cohorts involved in the European Prospective Investigation into Cancer and Nutrition (EPIC) study participating in the Diogenes project (named as “Diogenes cohort” in the following) with weight measurements at baseline and follow-up were used to predict future obesity prevalence with logistic linear and non-linear (leveling off) regression models. In addition, linear and leveling off models were fitted to the EPIC-Potsdam dataset with five weight measures during the observation period to find out which of these two models might provide the more realistic prediction.

Results

During a mean follow-up period of 6 years, the obesity prevalence in the Diogenes cohort increased from 13% to 17%. The linear prediction model predicted an overall obesity prevalence of about 30% in 2015, whereas the leveling off model predicted a prevalence of about 20%. In the EPIC-Potsdam cohort, the shape of obesity trend favors a leveling off model among men (R² = 0.98), and a linear model among women (R² = 0.99).

Conclusion

Our data show an increase in obesity prevalence since the 1990ies, and predictions by 2015 suggests a sizeable further increase in European populations. However, the estimates from the leveling off model were considerably lower.     

The influence of climatic seasonality on the diversity of different tropical pollinator groups

Tropical South America is rich in different groups of pollinators, but the biotic and abiotic factors determining the geographical distribution of their species richness are poorly understood. We analyzed the species richness of three groups of pollinators (bees and wasps, butterflies, hummingbirds) in six tropical forests in the Bolivian lowlands along a gradient of climatic seasonality and precipitation ranging from 410 mm to 6250 mm. At each site, we sampled the three pollinator groups and their food plants twice for 16 days in both the dry and rainy seasons. The richness of the pollinator groups was related to climatic factors by linear regressions. Differences in species numbers between pollinator groups were analyzed by Wilcoxon tests for matched pairs and the proportion in species numbers between pollinator groups by correlation analyses. Species richness of hummingbirds was most closely correlated to the continuous availability of food, that of bees and wasps to the number of food plant species and flowers, and that of butterflies to air temperature. Only the species number of butterflies differed significantly between seasons. We were not able to find shifts in the proportion of species numbers of the different groups of pollinators along the study gradient. Thus, we conclude that the diversity of pollinator guilds is determined by group-specific factors and that the constant proportions in species numbers of the different pollinator groups constitute a general pattern.     

First results of the investigation of the stability and tissue integration of a degradable, elastomeric copolymer in an animal model]

The stability and tight integration into adjacent tissue of a novel, degradable, elastic copolymer were examined in an animal model. The biomaterial was used for the reconstruction of a gastric wall defect in Sprague-Dawley rats (n=42) to test the polymeric material under the extreme chemical, enzymatical and mechanical conditions of the stomach. In the control group (n=21) the same defect of the gastric wall was primarily closed without biomaterial implantation. In the baseline group (n=21) the animals were kept under standard conditions without any surgical procedure. The implantation periods were 1 week, 4 weeks and 6 months. The animals' weight was determined preoperatively and before explantation. After explantation, air was pumped into the stomach and the pressure was measured by using a pressure-gauge in order to test whether the surgically produced union of the stomach wall and the polymer patch was gas-tight. After 1 week of implantation time a statistically significant increase of the body weight of the animals was found only in the baseline group. Four weeks and 6 months after the abdominal surgical procedure, a statistically significant increase of the animals' weight was found in the implantation group, the control and the baseline group. Gastrointestinal complications like fistula, perforation or peritonitis did not occur in any of the animals. The measurement of the stomach pressure after maximal gas insufflation did not show significant differences between the implantation group, the control and the baseline group in any of the time periods investigated. Despite very high strains of the gastric wall, no gas leakage was detected. There was a tight connection between the polymer and the adjacent stomach wall in all animals investigated. An adequate mechanical stability of the biomaterial was detectable under the extreme pathophysiological conditions of the stomach milieu. A fast and unfavourable degradation of the degradable polymer was not found in any of the animals. Further investigations are needed to analyse the mechanisms of the tissue integration of the biomaterial as well as the degradation kinetic of the polymer and the process of the tissue remodeling. The knowledge of these processes is necessary to adapt the novel biomaterial and thus prepare it for the use and implantation in different body locations and to develop novel therapeutical options in medicine.     

Preoperative mannan-binding lectin pathway and prognosis in colorectal cancer

Purpose: Deficiency of the mannan-binding lectin (MBL) pathway of innate immunity is associated with increased susceptibility to infections. In patients with colorectal cancer (CRC), postoperative infection is associated with poor prognosis. The aim of the present study was to evaluate (1) the relation between the MBL pathway and postoperative infectious complications and survival of patients resected for CRC, and (2) the role of MBL in acute phase response compared to C-reactive protein (CRP). Methods: Preoperative MBL concentration, MBL-associated serine protease (MBL/MASP) activity and CRP were determined in serum from 611 patients and 150 healthy controls. The patients were observed for 8 years. Postoperative infections, recurrence and survival were recorded. Results: The MBL pathway components were increased in the patients compared with the healthy controls (p<0.0001). Low MBL levels were predictive of pneumonia (p=0.01), and pneumonia (n=87) was associated with poor survival (p=0.003; HR=1.5; 95% CI, 1.1 to 1.9). MBL and MBL/MASP activity showed no correlation with CRP (Spearmans =0.02; 95% CI, –0.06 to 0.10). Conclusion: Low preoperative MBL levels are predictive of pneumonia, which is associated with poorer survival. MBL concentration and MBL/MASP activity was not predictive of other postoperative infections or long-term prognosis, and showed no correlation with CRP.