Comparison of anti-fracture effectiveness of zoledronate, ibandronate and alendronate versus denosumab in a registry-based cohort study.

This registry-based study of 3068 patients with osteoporosis compared the anti-fracture effectiveness of denosumab versus bisphosphonates. Denosumab was associated with significantly greater risk reduction than alendronate or ibandronate for vertebral and any fractures. No difference in fracture risk reduction was found between zoledronate and denosumab. PURPOSE: To analyse the fracture risk of patients with osteoporosis receiving bisphosphonates or denosumab in a real-world setting. METHODS: This registry-based cohort study evaluated patients taking denosumab, bisphosphonates or both sequentially. Fractures were analysed using rates, rate ratios and hazard ratios (HR), including both therapies as time-varying co-variates. Fracture risk hazards were adjusted (aHR) for baseline T-Scores and trabecular bone score (TBS) and were additionally analysed with inverse probability treatment weighting. RESULTS: A total of 3068 patients (89% female; median age at treatment onset, 69 years [63 to 76]) received denosumab (median duration 2.8 years, [2.2 to 4.7]), bisphosphonates (3.4 years, [2.1 to 5.7]) or both sequentially. Thus, 11,078 subject-years were assessed for bisphosphonates (41% alendronate, 36% ibandronate, 23% zoledronate) and 4216 for denosumab. Moreover, 48,375 subject-years were observed before treatment onset, in addition to 2593 years of drug holidays. A total of 1481 vertebral fractures (435 under therapy), 1508 non-vertebral fractures (499 under therapy) and 202 hip fractures (67 under therapy) occurred after age 50. The risks of vertebral, non-vertebral and hip fractures were significantly lower under all bisphosphonates, denosumab and drug holidays than before treatment onset (all p < 0.001). After adjusting for age, baseline T-scores and TBS, denosumab was associated with lower risk than alendronate or ibandronate for vertebral fractures (aHR 0.47 (0.35 to 0.64) and 0.70 [0.53 to 0.91], p < 0.001 and p = 0.009, respectively) and any fractures (aHR 0.62 [0.51 to 0.76] and 0.77 [0.64 to 0.92], p < 0.001 and p = 0.004). With propensity weighting, denosumab was associated with a lower hip fracture risk compared to alendronate (HR 0.54 [0.29 to 0.98], p = 0.044). No difference in fracture risk reduction (vertebral, non-vertebral or hip) was found between zoledronate and denosumab. CONCLUSIONS: When adjusting for disease severity, denosumab was associated with significantly greater risk reduction than alendronate and ibandronate for vertebral fractures. No difference in fracture risk reduction was found between zoledronate and denosumab.

Incidence of Atypical Femoral Fractures in Patients on Osteoporosis Therapy-A Registry-Based Cohort Study.

Atypical femoral fractures (AFFs) have been reported in patients taking bisphosphonates (BPs) for osteoporosis therapy but also in patients with no exposure to these drugs. In contrast, less is known about the incidence of AFFs in patients taking denosumab. This registry-based cohort study analyzed the incidence of AFFs in patients with suspected or confirmed osteoporosis who were included in the osteoporosis register of the Swiss Society of Rheumatology between January 2015 and September 2019. Statistical analyses included incidence rates, rate ratios, and hazard ratios for AFFs, and considered sequential therapies and drug holidays as time-dependent covariates. Among the 9956 subjects in the cohort, 53 had subtrochanteric or femoral shaft fractures. Ten fractures occurred under BP or denosumab treatment and two under teriparatide therapy. Five fractures were classified as AFFs based on the revised American Society of Bone and Mineral Research case definition of AFFs from 2014. Three AFFs occurred in women being treated with denosumab at the time of diagnosis, all with prior BP use (10, 7, and 1 years, respectively). One AFF developed in a woman receiving ibandronate and one arose in a woman receiving glucocorticoids rather than antiresorptive therapy. The incidence of AFFs per 10,000 observed patient-years was 7.1 in patients receiving denosumab and 0.9 in patients with BP-associated AFFs, yielding a rate ratio of 7.9 (95% confidence interval [CI] 0.63-413), p = 0.073. The risk of AFFs was not significantly higher in patients receiving denosumab therapy compared with BP therapy (hazard ratio = 7.07, 95% CI 0.74-68.01, p = 0.090). We conclude that the risk of AFFs is low in patients taking BPs, denosumab, or both sequentially. All three patients with AFFs under denosumab therapy had undergone prior BP therapy. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Risk of Osteonecrosis of the Jaw Under Denosumab Compared to Bisphosphonates in Patients With Osteoporosis.

Osteonecrosis of the jaw (ONJ) is a rare but serious adverse event associated with antiresorptive treatment. There is little evidence regarding the incidence of ONJ among patients with osteoporosis who are treated with denosumab versus bisphosphonates (BPs). The aim of this study was to determine the risk of ONJ in a real-world population. Subjects who underwent at least one dual-energy X-ray absorptiometry (DXA) examination were included in the osteoporosis register of the Swiss Society of Rheumatology between January 1, 2015, and September 30, 2019. Statistical analyses included incidence rates, rate ratios, and hazard ratios for ONJ, considering sequential therapies and drug holidays as covariates. Among 9956 registered patients, 3068 (89% female, median age 69 years [63 to 76]) were treated with BPs or denosumab for a cumulative duration of 11,101 and 4236 patient-years, respectively. Seventeen cases of ONJ were identified: 12 in patients receiving denosumab at the time of ONJ diagnosis and 5 in patients receiving oral or intravenous BP therapy. The diagnosis of ONJ was confirmed by independent and blinded maxillofacial surgeons, using the American Association of Oral and Maxillofacial Surgeons case definition of ONJ. The incidence of ONJ per 10,000 observed patient-years was 28.3 in patients receiving denosumab and 4.5 in patients with BP-associated ONJ, yielding a rate ratio of 6.3 (95% confidence interval [CI] 2.1 to 22.8), p < 0.001. Nine of 12 patients who developed ONJ during denosumab treatment had been pretreated with BPs, but none of the 5 patients with BP-related ONJ had previously received denosumab. The risk of ONJ was higher in patients receiving denosumab therapy compared with BPs (hazard ratio 3.49, 95% CI 1.16 to 10.47, p = 0.026). Previous BP therapy before switching to denosumab may be an additional risk factor for ONJ development. © 2021 American Society for Bone and Mineral Research (ASBMR).

Sex-Specific Human Cardiomyocyte Gene Regulation in Left Ventricular Pressure Overload.

OBJECTIVE: To assess gene expression in cardiomyocytes isolated from patients with aortic stenosis, hypothesizing that maladaptive remodeling and inflammation-related genes are higher in male vs female patients. PATIENTS AND METHODS: In this study, 34 patients with aortic stenosis undergoing aortic valve replacement from March 20, 2016, through May 24, 2017, at the German Heart Centre in Berlin, Germany, were included. Isolated cardiomyocytes from interventricular septum samples were used for gene expression analysis. Clinical and echocardiographic data were collected preoperatively. RESULTS: Age, body mass index, systolic and diastolic blood pressure, comorbidities, and medication were similar between the 17 male and 17 female patients. The mean ± SD left ventricular end-diastolic diameter (52±9 vs 45±4 mm; P=.007) and posterior wall thickness (14.2±2.5 vs 12.1±1.6 mm; P=.03) were higher in male vs female patients, while ejection fraction was lower in male patients (49%±14% vs 59%±5%; P=.01). Focusing on structural genes involved in the development of cardiac hypertrophy and remodeling, we found that most were expressed higher in male vs female patients. Our modeling analysis revealed that 2 inflammation-related genes, CCN2 and NFKB1, were negatively related to ejection fraction, with this effect being male specific (P=.03 and P=.02, respectively). CONCLUSION: These findings provide novel insight into cardiomyocyte-specific molecular changes related to sex differences in pressure overload and a significant male-specific association between cardiac function and inflammation-related genes. Considering these sex differences may contribute toward a more accurate design of research and the development of more appropriate therapeutic approaches for both male and female patients.

Abnormal aortic flow profiles persist after aortic valve replacement in the majority of patients with aortic valve disease: how model-based personalized therapy planning could improve results. A pilot study approach.

OBJECTIVES: Complex blood flow profiles in the aorta are known to contribute to vessel dilatation. We studied flow profiles in the aorta in patients with aortic valve disease before and after surgical aortic valve replacement (AVR). METHODS: Thirty-four patients with aortic valve disease underwent 4-dimensional velocity-encoded magnetic resonance imaging before and after AVR (biological valve = 27, mechanical valve = 7). Seven healthy volunteers served as controls. Eccentricity (ES) and complex flow scores (CFS) were determined from the degree of helicity, vorticity and eccentricity of flow profiles in the aorta. Model-based therapy planning was used in 4 cases to improve in silico postoperative flow profiles by personalized adjustment of size, rotation and angulation of the valve as well as aorta diameter. RESULTS: Patients with aortic valve disease showed more complex flow than controls [median ES 2.5 (interquartile range (IQR) 2.3-2.7) vs 1.0 (IQR 1.0-1.0), P < 0.001, median CFS 4.7 (IQR 4.3-4.8) vs 1.0 (IQR 1.0-2.0), P < 0.001]. After surgery, flow complexity in the total patient cohort was reduced, but remained significantly higher compared to controls [median ES 2.3 (IQR 1.9-2.3) vs 1.0 (IQR 1.0-1.0), P < 0.001, median CFS 3.8 (IQR 3.0-4.3) vs 1.0 (IQR 1.0-2.0), P < 0.001]. In patients after mechanical AVR, flow complexity fell substantially and showed no difference from controls [median ES 1.0 (IQR 1.0-2.3) vs 1.0 (IQR 1.0-1.0), P = 0.46, median CFS 1.0 (IQR 1.0-3.3) vs 1.0 (IQR 1.0-2.0), P = 0.71]. In all 4 selected cases (biological, n = 2; mechanical, n = 2), model-based therapy planning reduced in silico complexity of flow profiles compared to the existing post-surgical findings [median ES 1.7 (IQR 1.4-1.7) vs 2.3 (IQR 2.3-2.3); CFS 1.7 (IQR 1.4-2.5) vs 3.8 (IQR 3.3-4.3)]. CONCLUSIONS: Abnormal flow profiles in the aorta more frequently persist after surgical AVR. Model-based therapy planning might have the potential to optimize treatment for best possible individual outcome. CLINICAL TRIAL REGISTRATION NUMBER: clinicaltrials.gov NCT03172338, 1 June 2017, retrospectively registered; NCT02591940, 30 October 2015, retrospectively registered.

Assessment of Bones Deficient in Fibrillin-1 Microfibrils Reveals Pronounced Sex Differences.

Defects in the extracellular matrix protein fibrillin-1 that perturb transforming growth factor beta (TGFß) bioavailability lead to Marfan syndrome (MFS). MFS is an autosomal-dominant disorder, which is associated with connective tissue and skeletal defects, among others. To date, it is unclear how biological sex impacts the structural and functional properties of bone in MFS. The aim of this study was to investigate the effects of sex on bone microarchitecture and mechanical properties in mice with deficient fibrillin-1, a model of human MFS. Bones of 11-week-old male and female Fbn1mgR/mgR mice were investigated. Three-dimensional micro-computed tomography of femora and vertebrae revealed a lower ratio of trabecular bone volume to tissue volume, reduced trabecular number and thickness, and greater trabecular separation in females vs. males. Three-point bending of femora revealed significantly lower post-yield displacement and work-to-fracture in females vs. males. Mechanistically, we found higher Smad2 and ERK1/2 phosphorylation in females vs. males, demonstrating a greater activation of TGFß signaling in females. In summary, the present findings show pronounced sex differences in the matrix and function of bones deficient in fibrillin-1 microfibrils. Consequently, sex-specific analysis of bone characteristics in patients with MFS may prove useful in improving the clinical management and life quality of these patients, through the development of sex-specific therapeutic approaches.

Detection of phenol contamination in RNA samples and its impact on qRT-PCR results.

Residual phenol, carried over from RNA purification, can alter RNA concentration measurements and is assumed to inhibit PCR. Here, we demonstrate that Impurities A260 values of spectral content profiling (SCP) UV/Vis measurements correlated with phenol concentration, whereas absorbance ratios of classical UV/Vis systems failed to reliably detect phenol in RNA samples. Phenol contamination led to over- or underestimation of RNA concentration on UV/Vis systems, whereas it had no influence on fluorometry quantification. Wrong RNA concentration results led to altered template input in qRT-PCR and consequently caused quantification cycle (Cq) shifts, although ≤ 0.01% phenol had no direct influence.

An integrative systems approach identifies novel candidates in Marfan syndrome-related pathophysiology.

Marfan syndrome (MFS) is an autosomal dominant genetic disorder caused by mutations in the FBN1 gene. Although many peripheral tissues are affected, aortic complications, such as dilation, dissection and rupture, are the leading causes of MFS-related mortality. Aberrant TGF-beta signalling plays a major role in the pathophysiology of MFS. However, the contributing mechanisms are still poorly understood. Here, we aimed at identifying novel aorta-specific pathways involved in the pathophysiology of MFS. For this purpose, we employed the Fbn1 under-expressing mgR/mgR mouse model of MFS. We performed RNA-sequencing of aortic tissues of 9-week-old mgR/mgR mice compared with wild-type (WT) mice. With a false discovery rate <5%, our analysis revealed 248 genes to be differentially regulated including 20 genes previously unrelated with MFS-related pathology. Among these, we identified Igfbp2, Ccl8, Spp1, Mylk2, Mfap4, Dsp and H19. We confirmed the expression of regulated genes by quantitative real-time PCR. Pathway classification revealed transcript signatures involved in chemokine signalling, cardiac muscle contraction, dilated and hypertrophic cardiomyopathy. Furthermore, our immunoblot analysis of aortic tissues revealed altered regulation of pSmad2 signalling, Perk1/2, Igfbp2, Mfap4, Ccl8 and Mylk2 protein levels in mgR/mgR vs WT mice. Together, our integrative systems approach identified several novel factors associated with MFS-aortic-specific pathophysiology that might offer potential novel therapeutic targets for MFS.

Utility of food pellets containing 1-aminobenzotriazole for longer term in vivo inhibition of cytochrome P450 in mice.

1. The utility of 1-aminobenzotriazole (ABT), incorporated in food, has been investigated as an approach for longer term inhibition of cytochrome P450 (P450) enzymes in mice. 2. In rats, ABT inhibits gastric emptying, to investigate this potential limitation in mice we examined the effect of ABT administration on the oral absorption of NVS-CRF38. Two hour prior oral treatment with 100 mg/kg ABT inhibited the oral absorption of NVS-CRF38, Tmax was 4 hours for ABT-treated mice compared to 0.5 hours in the control group. 3. A marked inhibition of hepatic P450 activity was observed in mice fed with ABT containing food pellets for 1 month. P450 activity, as measured by the oral clearance of antipyrine, was inhibited on day 3 (88% of control), week 2 (83% of control) and week 4 (80% of control). 4. Tmax values for antipyrine were comparable between ABT-treated mice and the control group, alleviating concerns about impaired gastric function. 5. Inclusion of ABT in food provides a minimally invasive and convenient approach to achieve longer term inhibition of P450 activity in mice. This model has the potential to enable pharmacological proof-of-concept studies for research compounds which are extensively metabolised by P450 enzymes.

Assistive Device for Efficient Intravitreal Injections.

Intravitreal therapy is the most common treatment for many chronic ophthalmic diseases, such as age-related macular degeneration. Due to the increasing worldwide demand for intravitreal injections, there exists a need to render this medical procedure more time- and cost-efficient while increasing patient safety. The authors propose a medical assistive device that injects medication intravitreally. Compared to the manual intravitreal injection procedure, an automated device has the potential to increase safety for patients, decrease procedure times, allow for integrated data storage and documentation, and reduce costs for medical staff and expensive operating rooms. This work demonstrates the development of an assistive injection system that is coarsely positioned over the patient's head by the human operator, followed by automatic fine positioning and intravitreal injection through the pars plana. Several safety features, such as continuous eye tracking and iris recognition, have been implemented. The functioning system is demonstrated through ex vivo experiments with porcine eyes. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:752-762.].

Ultraviolet C radiation influences the robustness of RNA integrity measurement.

The analytical and clinical validity of analyses of RNA samples destined for clinical diagnosis and therapeutic management is directly impacted by RNA quality. RNA is affected by heat, enzymatic degradation, and Ultraviolet (UV) light. RNA from three eukaryotic cell lines was degraded by heat, RNase, or UV light. RNA integrity values obtained with the benchmark Agilent Bioanalyzer 2100 system were compared with those from the more recent QIAxcel Advanced system. The application of this novel method has allowed us to unravel differences between RNA biophysical and biochemical degradation modes. Agilent RNA integrity number (RIN) and QIAxcel RIS were comparable in heat-degraded and RNase III-degraded RNA. Agilent RIN and QIAxcel RIS were comparable at a RIN decision level of 7 in UV-degraded RNA but not overall. The QIAxcel RIS method was more precise than Agilent RIN for RIN<8, while the inverse was true for RIN≥8. Greater degradation of mRNA and rRNA in UV-damaged samples hampered the Agilent RIN calculation algorithm. Overall, RIS was more robust than RIN for assessing RNA integrity. The ΔΔCt-values for heat- and UV-degraded RNA samples showed slightly higher correlation with RIS than with RIN. RNA integrity can be used to categorize RNA samples for suitability for downstream gene expression analyses, independently of the RNA degradation mechanism. The new method QIAxcel is more robust and therefore allows more accurate categorization of compromised RNA samples.

Prevalence, virulence gene distribution and genetic diversity of Arcobacter in food samples in Germany.

This study was carried out to determine the prevalence of Arcobacter spp. in food samples in Germany. In addition, the presence of putative virulence genes and the genetic diversity was tested for Arcobacter (A.) butzleri strains isolated during this study. The prevalence of Arcobacter spp. was 34% in fish meat, 26.8% in poultry meat and 2% in minced meat (beef and pork). All investigated A. butzleri isolates carried the genes cadF, ciaB, cj1349, mviN and pldA. The gene tlyA was detectable in 97.5% of the strains. Lower detection rates were observed for hecA (47.5%), hecB (45%), iroE (40%) and irgA (35%). Genotyping by ERIC-PCR demonstrated a high genetic diversity of A. butzleri strains from different foods. In conclusion, this study shows that about one third of fish meat and poultry meat samples contained Arcobacter spp. These data highlight the need to strengthen our effort to elucidate the importance ofArcobacter on veterinary public health.

Intact bone vitality and increased accumulation of nonmineralized bone matrix in biopsy specimens of juvenile osteochondritis dissecans: a histological analysis.

BACKGROUND: Although commonly proposed to be the starting point of juvenile osteochondritis dissecans (JOCD), avascular osteonecrosis (AVN) has been an inconsistent finding in histological studies. Analysis of early-stage lesions is required to elucidate the origins of OCD and justify proper treatment. PURPOSE: To analyze histological sections of JOCD lesions with special emphasis on bone vitality. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Of 64 patients with 74 JOCD lesions (20 females, mean age, 11.4 years; 44 males, mean age, 12.7 years), 34 required surgery because of lesion instability or failed nonoperative treatment. From 9 patients, 11 histological specimens were obtained. Lesions were classified according to the International Cartilage Repair Society (ICRS). Two additional histological control sections were harvested from children without JOCD manifestation. Undecalcified histological sections were histomorphometrically analyzed. To analyze the skeletal health of the patients, biochemical analyses with special emphasis on bone metabolism were performed. RESULTS: Histologically, no osteonecrosis was visible in any of the cases. Osteocyte distribution was similar among OCD lesions and controls. ICRS OCD I lesions (n = 6) showed no intralesional separation. In ICRS OCD II and III lesions (n = 5), there was a subchondral fracture concomitant with histological characteristics of active repair mechanism (increased bone formation: osteoid volume P = .008, osteoblast number P = .046; resorption: osteoclast number P = .005; and tissue fibrosis compared with controls). Instead, in ICRS OCD I lesions, subchondral osteoid volume (P = .010) and osteoblast number (P = .046) were significantly increased compared with controls; however, no active repair mechanisms (no increased bone resorption or fibrous tissue) were detected, suggesting a focal lack of mineralization. Fifty-seven of 64 patients (89.1%) showed a vitamin D deficiency. The median vitamin D serum level of the patients with ICRS OCD I lesions was 13.6 µg/L. CONCLUSION: In the present study, osteonecrosis was not found in histological specimens of JOCD. As a secondary finding, focal accumulations of nonmineralized bone matrix indicating a lack of mineralization in ICRS OCD I lesions were revealed. This finding correlated with a low level of vitamin D in the affected children.

Thin films with high surface roughness: thickness and dielectric function analysis using spectroscopic ellipsometry.

An optical surface roughness model is presented, which allows a reliable determination of the dielectric function of thin films with high surface roughnesses of more than 10 nm peak to valley distance by means of spectroscopic ellipsometry. Starting from histogram evaluation of atomic force microscopy (AFM) topography measurements a specific roughness layer (RL) model was developed for an organic thin film grown in vacuum which is well suited as an example. Theoretical description based on counting statistics allows generalizing the RL model developed to be used for all non-conducting materials. Finally, a direct input of root mean square (RMS) values found by AFM measurements into the proposed model is presented, which is important for complex ellipsometric evaluation models where a reduction of the amount of unknown parameters can be crucial. Exemplarily, the evaluation of a N,N'-dimethoxyethyl-3,4,9,10-perylene-tetracarboxylic-diimide (DiMethoxyethyl-PTCDI) film is presented, which exhibits a very high surface roughness, i.e. showing no homogeneous film at all.

Temperature-dependent Raman investigation of rolled up InGaAs/GaAs microtubes.

Large arrays of multifunctional rolled-up semiconductors can be mass-produced with precisely controlled size and composition, making them of great technological interest for micro- and nano-scale device fabrication. The microtube behavior at different temperatures is a key factor towards further engineering their functionality, as well as for characterizing strain, defects, and temperature-dependent properties of the structures. For this purpose, we probe optical phonons of GaAs/InGaAs rolled-up microtubes using Raman spectroscopy on defect-rich (faulty) and defect-free microtubes. The microtubes are fabricated by selectively etching an AlAs sacrificial layer in order to release the strained InGaAs/GaAs bilayer, all grown by molecular beam epitaxy. Pristine microtubes show homogeneity of the GaAs and InGaAs peak positions and intensities along the tube, which indicates a defect-free rolling up process, while for a cone-like microtube, a downward shift of the GaAs LO phonon peak along the cone is observed. Formation of other type of defects, including partially unfolded microtubes, can also be related to a high Raman intensity of the TO phonon in GaAs. We argue that the appearance of the TO phonon mode is a consequence of further relaxation of the selection rules due to the defects on the tubes, which makes this phonon useful for failure detection/prediction in such rolled up systems. In order to systematically characterize the temperature stability of the rolled up microtubes, Raman spectra were acquired as a function of sample temperature up to 300°C. The reversibility of the changes in the Raman spectra of the tubes within this temperature range is demonstrated.

Magneto-optical Kerr effect spectroscopy--a sensitive tool for investigating the molecular orientation in organic semiconductor films.

The detection and control of the molecular growth mode is a key prerequisite for fabricating opto-electronic devices. In this work we present the magneto-optical Kerr effect (MOKE) spectroscopy to be a highly sensitive method for the detection of the molecular orientation. On the example of metal free phthalocyanine (H(2)Pc) in thin films, it will be shown that also for diamagnetic molecules a strong magneto-optical response can be expected. The growth mode and thus the intensity of the MOKE signal of H2Pc is strongly influenced by a templating effect using ultrathin layers of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA). From the MOKE spectra in the energy range from 1.5 to 5.0 eV and the optical constants, the Voigt constant of thin organic films was determined. From the strong in-plane/out-of-plane anisotropy of the optical constants and the value of the Voigt constant the average molecular tilt angle of H2Pc molecules with respect to the substrate plane can be obtained.

Carbon dioxide does not affect the methylation status of prognostic important oncogenes Rassf1A and DCR2 in neuroblastoma cells.

PURPOSE: The aim of the current study was to investigate effects of CO(2) atmosphere, mimicking conditions of the pneumoperitoneum during laparoscopy, on epigenetic conditions of Rassf1A and DCR2 oncogenes in neuroblastoma cells. METHODS: SH-SY5Y neuroblastoma cells were exposed to 100% CO(2) for 4 h. Cells were lysed 4, 8 and 168 h after exposure. After methylation analysis of Rassf1A and DCR2 with polymerase chain reaction, results were compared to those of physiologically incubated neuroblastoma cells. RESULTS: No significant changes were found after exposure to carbon dioxide compared to the control. Values of methylated Rassf1A were 12.6 +/- 1.1 versus 13.2 +/- 1.4 ng/microl in the controls, respectively (4 h after incubation), 12.6 +/- 1.2 versus 15.1 +/- 0.9 ng/microl (8 h) and 14.2 +/- 1.5 versus 11.7 +/- 1.3 ng/microl (168 h). DCR2 showed values of 4.6 +/- 0.5 versus 3.7 +/- 0.5 ng/microl (4 h), 3.8 +/- 0.5 versus 4.1 +/- 0.4 ng/microl (8 h) and 3.6 +/- 0.4 versus 3.8 +/- 0.5 ng/microl (168 h). CONCLUSION: Exposure of neuroblastoma cells to 100% CO(2) does not alter methylation of two prognostic relevant index genes. It seems therefore unlikely that effects on methylation levels within CO(2) pneumoperitoneum lead to epigenetic changes in neuroblastoma.

Cocrystallizing natural RNA with its unnatural mirror image: biochemical and preliminary X-ray diffraction analysis of a 5S rRNA A-helix racemate.

Chemically synthesized RNAs with the unnatural L-configuration possess enhanced in vivo stability and nuclease resistance, which is a highly desirable property for pharmacological applications. For a structural comparison, both L- and D-RNA oligonucleotides of a shortened Thermus flavus 5S rRNA A-helix were chemically synthesized. The enantiomeric RNA duplexes were stochiometrically cocrystallized as a racemate, which enabled analysis of the D- and L-RNA enantiomers in the same crystals. In addition to a biochemical investigation, diffraction data were collected to 3.0 A resolution using synchrotron radiation. The crystals belonged to space group P3(1)21, with unit-cell parameters a = b = 35.59, c = 135.30 A, gamma = 120 degrees and two molecules per asymmetric unit.

Polychlorinated biphenyl exposure causes gonadal atrophy and oxidative stress in Corbicula fluminea clams.

Polychlorinated biphenyls (PCBs) are widespread environmental contaminants that have been linked to oxidative and other toxic effects in both humans and wildlife. Due to recent environmental health concerns at a PCB contaminated Superfund site near Raleigh, NC, we used a common clam species (Corbicula fluminea) as surrogates to isolate the effects of PCBs on threatened bivalves native to the region. Under controlled laboratory conditions, clams were exposed to 0, 1, 10, or 100 ppb Aroclor 1260 in the ambient water for 21 days. Measured biomarkers spanned a range of effective levels of biological organization including low molecular weight antioxidants, lipid-soluble antioxidants, and whole tissue radical absorption capacity. These data were augmented by use of histological evaluation of whole samples. Aroclor 1260 significantly increased reduced glutathione (GSH) and total protein concentrations at all treatments levels. Significant decreases were measured in all treatments in gamma -tocopherol and total oxidant scavenging capacity (TOSC) and alpha -tocopherol values in the 100 ppb exposure. Histologically, Aroclor 1260 caused significant gonadal atrophy, effacement of gonad architecture with accumulations of Brown cells, and inflammation and necrosis in digestive glands and foot processes. Our results indicate that oxidative mechanisms play a significant role in the decreased health of these clams due to exposure to Aroclor 1260. The changes in the gonads of exposed clams suggest that a serious threat to bivalve reproduction exists due to PCB exposure.