Reduced bioavailability of Au and isotopically enriched 109Ag nanoparticles transformed through a pilot wastewater treatment plant in Hyallela azteca under environmentally relevant exposure scenarios.

Wastewater Treatment Plants (WWTP) are a major repository and entrance path of nanoparticles (NP) in the environment and hence play a major role in the final fate and toxicity to biota of NP in the aquatic environment. Studies on silver nanoparticles (AgNP) transport via the WWTP system and uptake by aquatic biota have so far been carried out using unrealistically high AgNP concentrations, unlikely to be encountered in the aquatic environment. The use of high AgNP concentrations is necessitated by both the low sensitivity of the detection methods used and the need to distinguish background Ag from spiked AgNP. In this study, isotopically enriched 109AgNP were synthesized to overcome these shortcomings and characterized by a broad range of methods including transmission electron microscopy, dynamic and electrophoretic light scattering. 109AgNP and gold NP (AuNP) were spiked to a pilot wastewater treatment plant fed with municipal wastewater for up to 21 days. AuNP were used as chemically less reactive tracer. The uptake of the pristine and transformed NP present in the effluent was assessed using the benthic amphipod Hyalella azteca in fresh- and brackish water exposures at environmentally relevant concentrations of 30 to 500 ng Au/L and 39 to 260 ng Ag/L. The unique isotopic signature of the 109AgNP allowed to detect the material at environmentally relevant concentrations in the presence of a much higher natural Ag background. The results show that the transformations reduce the NP uptake at environmentally relevant exposure concentrations. For 109Ag, lower accumulation factors (AF) were obtained after exposure to transformed NP (250-350) compared to the AF values obtained for pristine 109AgNP (750-840). The reduced AF values observed for H. azteca exposed to effluent from the AuNP-spiked WWTP indicate that biological transformation processes (e.g. eco-corona formation) seem to be involved in addition to chemical transformation.

3D assessment after maxillary sinus grafting with a porcine, a bovine and a synthetical bone substitute material. A randomized controlled clinical trial.

AIM: This randomized controlled clinical study focused on graft volume alterations after sinus floor augmentation with a deproteinized bovine bone mineral (DBBM, Geistlich Bio-Oss®), deproteinized porcine bone mineral (DPBM, THE GRAFT®) or a biphasic calcium phosphate (BCP, OSOPIA®). MATERIAL AND METHODS: 28 patients with edentulous situations in the posterior maxilla with less or equal to 5 mm of residual bone height received a two- staged external sinus grafting procedure with DBBM, DPBM or BCP. CBCT scans were performed prior surgery (CBCT1), directly after surgery (CBCT2) and after a healing period of 4-6 months prior implant placement (CBCT3). CBCT scans were used to analyze volumetric alterations of the sinus grafts by virtual 3D model matching of CBCT1- CBCT2 (situation after sinus grafting) and CBCT1 and CBCT2 (situation prior implant placement). RESULTS: The volume of the bone graft in the maxillary sinus (volume (VOL%) directly after grafting rated as 100%) was stable after the healing period in the DBBM (VOL%: 103±4%) and the PBBM groups (VOL%: 112± 23) with no statistically significant differences concerning 3D measurements. In the BCP group, the grafted volume declined to 66± 25% (VOL%), statistically inferior to the DBBM and DPBM groups. CONCLUSION: Concerning bone graft stability/ 25 volume DBBM and DPBM show comparable outcomes. Due to resorption, BCP showed inferior bone graft volume after healing (statistically significant) compared to DBBM and DPBM.

Clean feed as countermeasure to reduce the 90Sr and 137Cs levels in fish from contaminated lakes.

Glubokoye Lake situated within the Chernobyl Exclusion Zone is highly contaminated with respect to radioactive caesium and strontium isotopes, which also is reflected in the contaminated fish. To utilize the fish resources in contaminated lakes, the present work presents for the first time the effectiveness of using clean feed to counteract contamination of radionuclides in fish. The study is based on a series of repeated experiments with Prussian carp (Carassius gibelio (Bloch, 1782)) kept in cages in the contaminated Glubokoye Lake during summer 2018-2021. By the addition of clean feed, the activity concentration of 137Cs in fish muscle tissues was lowered with a factor of 2-5 due to biodilution. Surprisingly, additional clean feed did not lead to further decrease in the uptake of 137Cs in fish. In contrast to 137Cs, the addition of clean feed increased the 90Sr activity concentration in fish by a factor of 2-4 compared to fish fed with naturally occurring feed items. Radioactive strontium accumulated mainly in the fish bones and the muscle tissue level was 2 orders of magnitude lower, similar to the distribution observed for stable Sr. By utilizing a new kinetic model describing the dynamics of strontium isotopes in bone tissues of fish, predictions fitted well with site-specific data, taking growth rates and aging into account. Results showed that clean feeding can be used to counteract high activity concentration of 137Cs in fish due to biodilution, but cannot counteract bioaccumulation of 90Sr. Findings highlighted that it is essential to understand underlying factors influencing the uptake pathways for contaminants, as access to clean feed could increase the growth and thereby reduce the body activity concentration of dietary associated radionuclides such as 137Cs (biodilution), as well as increase the transfer of dissolved compounds such as 90Sr directly from water to fish.

Mitral Annular Elasticity Determines Severity of Regurgitation in Barlow's Mitral Valve Disease.

OBJECTIVES: Barlow's mitral valve disease with late systolic mitral regurgitation provides diagnostic and therapeutic challenges. The mechanisms of the regurgitation are still unclear. We hypothesized that the onset and the severity of late systolic regurgitation are determined by annulus dynamics and the mechanical stresses imposed by the left ventricle. METHODS: Ten patients with Barlow's mitral valve disease and mitral annulus disjunction (MAD) were compared with 10 healthy controls. Resting blood pressure was measured, and transthoracic three-dimensional echocardiography was analyzed using a holographic display that allows tracking and measurements of mitral annulus surface area (ASA) throughout the cardiac cycle. A novel annulus elastance index (dASA/dP) was calculated between aortic valve opening and onset of mitral regurgitation. Severity of MAD was quantified as the disjunction index (mm × degree). Leaflet coaptation area was calculated using a finite element model. RESULTS: Peak systolic ASAs in controls and patients were 9.3 ± 0.6 and 21.1 ± 3.1 cm2, respectively (P < .001). In patients, the ASA increased rapidly during left ventricular ejection, and onset of mitral regurgitation coincided closely with peak upslope of annulus area change (dASA/dt). The finite element model showed a close association between rapid annulus displacement and coaptation area deficit in Barlow's mitral valve disease. Systolic annulus elastance index (0.058 ± 0.036 cm2/mm Hg) correlated strongly with disjunction index (r = 0.91, P < .0001). Moreover, regurgitation volume showed a positive correlation with systolic blood pressure (r = 0.80, P < .01). CONCLUSION: The present pilot study supports the hypothesis that annulus dilatation may accentuate mitral valve regurgitation in patients with Barlow's mitral valve disease. A novel annulus elastance index may predict the severity of mitral valve regurgitation in selected patients.

SARS-CoV-2 Infects Red Blood Cell Progenitors and Dysregulates Hemoglobin and Iron Metabolism.

BACKGROUND: SARS-CoV-2 infection causes acute respiratory distress, which may progress to multiorgan failure and death. Severe COVID-19 disease is accompanied by reduced erythrocyte turnover, low hemoglobin levels along with increased total bilirubin and ferritin serum concentrations. Moreover, expansion of erythroid progenitors in peripheral blood together with hypoxia, anemia, and coagulopathies highly correlates with severity and mortality. We demonstrate that SARS-CoV-2 directly infects erythroid precursor cells, impairs hemoglobin homeostasis and aggravates COVID-19 disease. METHODS: Erythroid precursor cells derived from peripheral CD34+ blood stem cells of healthy donors were infected in vitro with SARS-CoV-2 alpha variant and differentiated into red blood cells (RBCs). Hemoglobin and iron metabolism in hospitalized COVID-19 patients and controls were analyzed in plasma-depleted whole blood samples. Raman trapping spectroscopy rapidly identified diseased cells. RESULTS: RBC precursors express ACE2 receptor and CD147 at day 5 of differentiation, which makes them susceptible to SARS-CoV-2 infection. qPCR analysis of differentiated RBCs revealed increased HAMP mRNA expression levels, encoding for hepcidin, which inhibits iron uptake. COVID-19 patients showed impaired hemoglobin biosynthesis, enhanced formation of zinc-protoporphyrine IX, heme-CO2, and CO-hemoglobin as well as degradation of Fe-heme. Moreover, significant iron dysmetablolism with high serum ferritin and low serum iron and transferrin levels occurred, explaining disturbances of oxygen-binding capacity in severely ill COVID-19 patients. CONCLUSIONS: Our data identify RBC precursors as a direct target of SARS-CoV-2 and suggest that SARS-CoV-2 induced dysregulation in hemoglobin- and iron-metabolism contributes to the severe systemic course of COVID-19. This opens the door for new diagnostic and therapeutic strategies.

Multimodal human thymic profiling reveals trajectories and cellular milieu for T agonist selection.

To prevent autoimmunity, thymocytes expressing self-reactive T cell receptors (TCRs) are negatively selected, however, divergence into tolerogenic, agonist selected lineages represent an alternative fate. As thymocyte development, selection, and lineage choices are dependent on spatial context and cell-to-cell interactions, we have performed Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq) and spatial transcriptomics on paediatric human thymu​​s. Thymocytes expressing markers of strong TCR signalling diverged from the conventional developmental trajectory prior to CD4+ or CD8+ lineage commitment, while markers of different agonist selected T cell populations (CD8αα(I), CD8αα(II), T(agonist), Treg(diff), and Treg) exhibited variable timing of induction. Expression profiles of chemokines and co-stimulatory molecules, together with spatial localisation, supported that dendritic cells, B cells, and stromal cells contribute to agonist selection, with different subsets influencing thymocytes at specific developmental stages within distinct spatial niches. Understanding factors influencing agonist T cells is needed to benefit from their immunoregulatory effects in clinical use.

Seasonal changes in uptake and depuration of 137Cs and 90Sr in silver Prussian carp (Carassius gibelio) and common rudd (Scardinius erythrophthalmus).

Dynamic transfer of radionuclides to fish was studied in a series of experiments under field condition in two lakes within the Chernobyl exclusion zone during 2016-2020. "Clean" common rudd (Scardinius erythrophthalmus) and silver Prussian carp (Carassius gibelio) were transported to the contaminated Glubokoye Lake and kept in cages during several months of exposure, while contaminated Glubokoye fish were kept in cages in the "clean" Starukha Lake. Radiocaesium (137Cs) and radiostrontium (90Sr) were determined in intestine contents, muscle and bone tissues based on repeated samples during several months of exposure. During summer, the activity concentrations of 137Cs and 90Sr increased with time of exposure in clean fish caged in the contaminated lake. During autumn and winter, however, minor changes in fish uptake occurred during several weeks of exposure to the contaminated water. Furthermore, depuration in the contaminated fish was significant during summer, while insignificant during winter when exposed in the «clean¼ water. The rate constant of 137Cs uptake in muscle was between 8.0 and 22 day-1 during summer, while 0.2 to 1.0 day-1 during autumn-winter. Similarly, the rate constant of 90Sr uptake in bone was between 1.4 and 1.6 day-1, while 0.08-0.52 day-1 during autumn-winter. Biological half-lives of 137Cs in fish muscle tissue in summer were 77 ± 10 days, while exceeded 230 days during seasons at low water temperature. The results demonstrated that the transfer of 137Cs and 90Sr to fish was highly dependent upon seasons, in particular the water temperature. The transfer data obtained during low water temperature seasons deviated significantly from transfer data in literature and handbooks. Thus, seasonal changes in radionuclide transfer to fish should be taken into account when radiological impact to fish is assessed.

The effect of polyethylenglycol gel on the delivery and osteogenic differentiation of homologous tooth germ-derived stem cells in a porcine model.

OBJECTIVES: The aim of this study was to investigate if bone regeneration can be promoted by homologous transplantation of STRO-1 sorted (STRO-1+) porcine tooth germ mesenchymal stem cells (TGSCs) with the combination of polyethylenglycol (PEG)-based hydrogel and biphasic calcium phosphate (BCP) scaffolds. MATERIAL AND METHODS: TGSCs were isolated from impacted third molars of domestic pigs. Nine critical-sized defects were created as (1) untreated defect; filled with (2) autogenous bone; (3) BCP + PEG; (4) BCP + PEG + unsorted TGSCs; (5) BCP + unsorted TGSCs; (6) BCP + PEG + STRO-1-sorted TGSCs; (7) BCP + STRO-1-sorted TGSCs; (8) BCP + PEG + osteogenic induced unsorted TGSCs; and (9) BCP + PEG + osteogenic induced STRO-1-sorted TGSCs in 20 domestic pigs. CM-DiI labelling was used to track cells in vivo. Histomorphometric assessment of new bone formation was achieved by toluidine blue O staining and microradiography after 1, 2, 4 and 12 weeks posttransplantation. RESULTS: Complete healing was achieved in all defects although defects with PEG hydrogel presented better bone formation while STRO-1+ and unsorted TGSCs showed similar ability to form new bone after 12 weeks. Transplanted cells were seen in defects where PEG hydrogel was used as carriers in contrast to defects treated with cells and only bone grafts. CONCLUSIONS: PEG hydrogel is an efficient carrier for homologous stem cell transplantation. TGSCs are capable of promoting bone healing in critical-sized defects in combination with bone graft and PEG hydrogel. CLINICAL RELEVANCE: This study provides information about the importance of the delivery vehicle for future translational stem cell delivery approaches.

A Novel Resorbable Composite Material Containing Poly(ester-co-urethane) and Precipitated Calcium Carbonate Spherulites for Bone Augmentation-Development and Preclinical Pilot Trials.

Polyurethanes have the potential to impart cell-relevant properties like excellent biocompatibility, high and interconnecting porosity and controlled degradability into biomaterials in a relatively simple way. In this context, a biodegradable composite material made of an isocyanate-terminated co-oligoester prepolymer and precipitated calcium carbonated spherulites (up to 60% w/w) was synthesized and investigated with regard to an application as bone substitute in dental and orthodontic application. After foaming the composite material, a predominantly interconnecting porous structure is obtained, which can be easily machined. The compressive strength of the foamed composites increases with raising calcium carbonate content and decreasing calcium carbonate particle size. When stored in an aqueous medium, there is a decrease in pressure stability of the composite, but this decrease is smaller the higher the proportion of the calcium carbonate component is. In vitro cytocompatibility studies of the foamed composites on MC3T3-E1 pre-osteoblasts revealed an excellent cytocompatibility. The in vitro degradation behaviour of foamed composite is characterised by a continuous loss of mass, which is slower with higher calcium carbonate contents. In a first pre-clinical pilot trial the foamed composite bone substitute material (fcm) was successfully evaluated in a model of vertical augmentation in an established animal model on the calvaria and on the lateral mandible of pigs.

Correction to: Osseous ingrowth in allogeneic bone blocks applied for vertical bone augmentation: a preclinical randomized controlled study.

In the article by Möst et al., entitled "Osseous ingrowth in allogeneic bone blocks applied for vertical bone augmentation: a preclinical randomized controlled study.

A new standardized critical size bone defect model in the pig forehead for comparative testing of bone regeneration materials.

OBJECTIVES: The preclinical study aimed to establish a standardized preclinical model to investigate osseous graft consolidation in defect configurations of limited regenerative capacity. MATERIAL AND METHODS: Critical size defects (CSD) were prepared and titanium tubes inserted for defect separation from local bone in the forehead area of 18 pigs. Defects were filled with demineralized bovine bone mineral (DBBM) or served as empty controls and were covered with a resorbable collagen membrane (CM) or left untreated. Six randomly selected pigs were sacrificed after 4, 8 and 12 weeks. Specimens were histologically and histomorphometrically analysed focusing on newly formed bone (NFB), demineralized bovine bone mineral (DBBM) and soft tissue (ST) proportions. RESULTS: Four weeks after defect preparation, no statistically significant difference concerning NFB quantity could be detected within the groups. Defects covered with the CM showed lower amounts of DBBM. After 6 and 12 weeks, defects augmented with DBBM in combination with a CM (8 weeks: 43.12 ± 4.31; 12 weeks: 43.05 ± 3.01) showed a statistically significant higher NFB rate compared to empty control defects covered with 8 weeks: 7.66 ± 0.59; 12 weeks or without a CM; 8 weeks: 8.62 ± 2.66; 12 weeks: 18.40 ± 2.40. CM application showed no significant impact on osseous defect regeneration or soft tissue formation. Superior NFB could be detected for basal aspect for several evaluation time points. CONCLUSIONS: The modification of CSD with titanium tubes represents a suitable model to imitate a one-wall defect regeneration situation. CLINICAL RELEVANCE: The established model represents a promising method to evaluate graft consolidation in one-wall defect configuration.

Osseous ingrowth in allogeneic bone blocks applied for vertical bone augmentation: a preclinical randomised controlled study.

OBJECTIVES: The aim of the present study was the qualitative and quantitative evaluation of osseous graft consolidation using allogeneic bone blocks for vertical bone augmentation in an animal model. MATERIAL AND METHODS: Standardised allogeneic and autologous bone blocks were fixed on the frontal skull of 20 adult female pigs and covered with a resorbable collagen membrane. Animals were sacrificed after 2 and 6 months. Specimens were histologically and histomorphometrically analysed focusing on the amount of vital bone, residual bone substitute material and connective tissue. Furthermore, the amount of expression of bone matrix proteins (collagen type I and osteocalcin) and de novo vessel formation (von Willebrand factor) were quantified by immunohistochemistry. RESULTS: Significantly more allogeneic bone blocks failed for both evaluation time points (p < 0.05). Allogeneic blocks showed significantly less vital bone with more connective tissue formation compared to autologous bone blocks. Increased vessel formation could be detected for both evaluation time points in the contact area of autologous bone with local bone. The expression of collagen type I and osteocalcin was significantly lower in the allogeneic bone graft. CONCLUSIONS: Allogeneic cancellous bone blocks showed a significantly higher failure rate compared to autologous bone blocks. Allogeneic bone blocks seemed to negatively affect bone formation or negatively influence the host in the long term, and increased connective tissue formation and block loss should be anticipated. CLINICAL RELEVANCE: In order to maintain patient safety and treatment success clinicians should be persuaded to make a conscious choice of the applied biomaterials with regard to their components and structure.

Gingiva thickening with a porcine collagen matrix in a preclinical dog model: Histological outcomes.

AIM: To compare 10-month histological and immunohistological outcomes after soft tissue thickening around teeth with a porcine collagen matrix (CM) versus a subepithelial connective tissue graft (SCTG). MATERIAL AND METHODS: In eight beagle dogs, soft tissue thickening of the buccal gingiva of upper canines was performed with the SCTG or the CM. Connective tissue thickness (CTT) was histomorphometrically measured in the augmented regions. The augmented connective tissues were also histologically characterized and the collagen I and vascular endothelial growth factor (VEGF) expressions immunohistologically quantified. RESULTS: CTT significantly differed between groups (SCTG: 1.32 mm ± 0.44 mm; CM: 1.06 mm ± 0.27 mm; p = .008). Descriptive histological analyses revealed mature connective tissue that did not differ between groups. Immunohistological quantification of collagen I and VEGF expressions in the connective tissue also revealed no significant inter-group differences (collagen I: SCTG, 32.64% ± 7.09% vs. CM, 30.57% ± 7.83%; VEGF: SCTG, 39.06% ± 7.27% vs. CM, 37.15% ± 9.80%). CONCLUSION: SCTG is superior to CM with regard to CTT in this experimental model. The CM and the SCTG lead to comparable connective tissue quality ten months after connective tissue thickening.

Papilla-Crown Height Dimensions around Zirconium Dioxide Implants in the Esthetic Area: A 3-Year Follow-Up Study.

PURPOSE: Soft tissue interactions with ceramic dental implants have previously been shown to have favorable esthetic outcomes. This study aimed to evaluate the papilla-crown proportion around zirconia implants in a 3-year follow-up study and the correlation between the gingival biotype and changes in papillary height. MATERIALS AND METHODS: This was a prospective study of 39 patients with 40 single-gap implants (Straumann PURE Ceramic ZLA Implant). The papilla-crown proportion was assessed after 3 months, 1 year, and 3 years. In addition, correlations between the peri-implant biotypes and changes in papillary heights were evaluated. RESULTS: The papilla-crown proportion improved from 35.5% after 3 months to 41.7% after 3 years. The gingival biotype was correlated very weakly to papilla height alterations. Significant papillary fill was observed in the interdental space between 3 months and 3 years (p < 0.001). CONCLUSIONS: An ideal papilla-crown proportion of 40% around single implants was observed after 3 years. A thin or thick gingival biotype showed a very weak correlation with soft tissue alterations.

Experimental peri-implant mucositis around titanium and zirconia implants in comparison to a natural tooth: part 1-host-derived immunological parameters.

The purpose of this study was to assess host-derived parameters around dental zirconia and titanium implants and natural teeth during the occurrence of mucositis. After 4 weeks of perfect oral hygiene, 16 clinically profiled patients were asked to refrain from oral hygiene for 2 weeks, resulting in experimental plaque accumulation. This was followed by 4 weeks of perfect oral hygiene to reverse the inflammation. Immunological samples were analyzed for interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-α), and interleukin 1ß (IL-1ß). Immunological parameters were measured each week, starting at week 4 (session 2) and ending at week 10 (session 8). There were significant differences in IL-6 between the groups (zirconia vs. tooth and titanium vs. tooth), with unfavourable values for the tooth unit (P<0.05). After reinstitution of oral hygiene, there was a significant increase in TNF-α values for the tooth but not for the zirconia and titanium implants. There were significant differences in IL-1ß between the groups (zirconia vs. titanium and titanium vs. tooth), with higher IL-1ß levels around titanium implants (P<0.05). The soft tissue around titanium implants developed a stronger inflammatory response to experimental plaque accumulation in terms of IL-1ß values, whereas the teeth presented an increase in IL-6 and TNF-α values.

Validation of a Holographic Display for Quantification of Mitral Annular Dynamics by Three-Dimensional Echocardiography.

BACKGROUND: Three-dimensional (3D) echocardiography with multiplanar reconstruction (MPR) is used clinically to quantify the mitral annulus. MPR images are, however, presented on a two-dimensional screen, calling into question their accuracy. An alternative to MPR is an autostereoscopic holographic display that enables in-depth visualization of 3D echocardiographic data without the need for special glasses. The aim of this study was to validate an autostereoscopic display using sonomicrometry as a gold standard. METHODS: In 11 anesthetized open-chest pigs, sonomicrometric crystals were placed along the mitral annulus and near the left ventricular apex. High-fidelity catheters measured left atrial and ventricular pressures. Adjustments of pre- and afterload were done by constriction of the inferior vena cava and the ascending aorta, respectively. Three-dimensional epicardial echocardiography was obtained from an apical view and converted to the autostereoscopic display. A 3D virtual semitransparent annular surface (VSAS) was generated to measure commissure width (CW), septal-lateral length, area of the mitral annular surface, nonplanarity angle, and the annular height-to-commissure width ratio in mid-systole and late diastole. RESULTS: Mitral annular measurements from the 3D VSAS derived from the 3D echocardiographic images and autostereoscopic display correlated well with sonomicrometry over a range of loading conditions: CW length (r = 0.98, P < .00001), septal-lateral length (r = 0.98, P < .00001), annular surface area (r = 0.93, P < .001), nonplanarity angle (r = 0.87, P < .001), and annular height-to-commissure width ratio (r = 0.85, P < .01). The 3D VSAS showed better agreement with the sonomicrometric measurements compared with MPR. CONCLUSIONS: Mitral annular measurements using 3D VSAS correlate well with sonomicrometry over a range of loading conditions and may represent a powerful tool for noninvasive quantification of mitral annular dynamics.

Human immunodeficiency virus 1 dual-target nucleic acid technology improves blood safety: 5 years of experience of the German Red Cross blood donor service Baden-Württemberg-Hessen.

BACKGROUND: RNA viruses are associated with a high frequency of mutations because of the missing proofreading function of polymerases, such as reverse transcriptase. Between 2007 and 2010, six blood donations with false-negative nucleic acid technology (NAT) results were reported in Germany. Therefore, NAT screening in two viral genome regions was introduced by our blood donation service in 2010 on a voluntary basis and became mandatory in Germany since the beginning of 2015. STUDY DESIGN AND METHODS: Blood donor screening was done using, in parallel, the German Red Cross (GRC) HIV-1 CE long terminate repeats (LTR) PCR kit and the GRC HIV-1 gag CE PCR kit. In total, 7 million blood donations were screened during the study period from 2010 to 2014 with the GRC dual-target human immunodeficiency virus 1 (HIV-1) NAT system. Additionally, three suspicious specimens were analyzed by four monotargeted NAT assays and by five dual-target NAT assays. RESULTS: Three of 7 million donations tested negative using the 5'LTR-polymerase chain reaction, but they were positive if amplification was performed in the gag region. HIV antibodies were detected in all three donations. Nucleic acid sequence analysis identified a deletion of 22 bases within the 5'LTR probe binding region. Three different ltr-based monotargeted assays missed two donations, except for a low-reactive result obtained by one of the assays. In total, the detection rates for HIV-1-positive donations were 37.5% (3/8) for monotargeted assays and 100% (10/10) for dual-target assays. CONCLUSION: The current data demonstrate that dual-target NAT systems reduce the risk of false-negative HIV-1 NAT screening results.

Tracing simultaneous cadmium accumulation from different uptake routes in brown crab Cancer pagurus by the use of stable isotopes.

High concentrations of cadmium in brown crab are an issue of food safety, and large variations between different areas have been found. To investigate the relative importance of dietary and aqueous uptake regarding the overall accumulation in brown crab, we used stable isotopes to trace the uptake from both routes simultaneously in the same animals. We demonstrated that the analytical challenges regarding background concentrations of natural isotope distribution and polyatomic interferences in the different matrices can be overcome with an appropriate analytical setup and modern mathematical corrections using a computer software. Cadmium was accumulated via both routes and was found in all measured organs at the end of the exposure phase. The obtained data were used to establish accumulation curves for both uptake routes and estimate accumulation parameters for hepatopancreas, as the most important organ in crab regarding total cadmium body burden. Using the estimated parameters in combination with naturally relevant cadmium concentrations in seawater and diet in a model, allowed us to predict the relative importance of the aqueous and dietary uptake route to the total hepatopancreas burden. According to the prediction, the dietary route is the main route of uptake in brown crab with a minimum of 98% of the accumulated cadmium in hepatopancreas originating from diet. Future studies addressing the source and accumulation of cadmium in crab should therefore focus on the uptake from feed and factors connected to foraging.

Role of STRO-1 sorting of porcine dental germ stem cells in dental stem cell-mediated bone tissue engineering.

Stem cells of dental origin emerged as a new source for the regeneration of tissues with advantages mainly including non-invasive collection procedures and lack of ethical contraversies with their harvest or use. In this study, porcine TGSCs (pTGSCs) were isolated from mandibular third molar tooth germs of 6-month-old domestic pigs. This is the first study that reports the isolation and characterization of TGSCs from porcine third molars and their differentiation depending on STRO-1 expression. PTGSCs were sorted according to their STRO-1 expression as STRO-1(+) and STRO-1(-). Sorted and unsorted heterogenous cells (US) were characterized by their osteogenic, chondrogenic and adipogenic differentiation capabilities. STRO-1(+) cells exhibited a higher proliferation rate owing to their clonogenic properties. All three groups of cells were found differentiated into osteogenic lineage as shown by ALP activity, calcium deposition assay, detection of osteogenic mRNAs and, proteins and mineralization staining. According to differentiation analysis, STRO-1(+) cells did not show a better performance for osteogenesis compared to STRO-1(-) and US cells. This might indicate that STRO-1(+) cells might require a heterogeneous population of cells including STRO-1(-) in their niche to perform their proposed role in osteogenesis.