NBD Group Research Articles

Polydimethylsiloxanes - Based Fluorescent Probe for H2S Detection in Living Cells.

The development of fluorescent probes for H2S detection especially in living cells is of great significance due to its fundamental role as signal molecule. A promising scaffold for the development of such probes is polydimethylsiloxanes (PDMS), which is cost-effectiveness, non-toxicity, flexibility, and biocompatibility and easy to post-functionalize. Surprisingly, fluorescent probes for H2S detection based on PDMS have not been investigated. Moreover, 4-nitro - 2,1,3-benzoxadiazole (NBD) derivates provides high fluorescence quantum yield, a large molar absorption coefficient, and sensitivity to environmental changes. Through reasonable design and adjustment of substituents on the NBD group, precise control of its fluorescence properties can be achieved. Herein, a novel H2S fluorescent probe, P-NBD, was designed and synthesized by a one-step aromatic ring nucleophilic substitution of Cl-NBD with a PDMS derivative. Due to the occurrence of the cleavage reaction strategy and the intramolecular charge transfer process, P-NBD can detect H2S via a colorimetric method. The limit of detection is down to 93 nM. P-NBD demonstrated considerable detection capability comparable to other reported types of H2S probes. Moreover, the probe can also be utilized for H2S imaging in HeLa cells. This work provides new insights into the design and synthesis of novel H2S probes while also offering experimental evidence for the application of PDMS in cellular imaging.

Real-World Safety and Effectiveness of Infliximab in 255 Patients with Intestinal, Neurological, and Vascular Behçet's Disease: A Post-Marketing Surveillance.

Behçet's disease (BD) with intestinal, neurological (NBD), and vascular (VBD) manifestations often leads to poor outcomes. Infliximab is approved for the treatment of intestinal BD, NBD, and VBD in Japan; however, evidence regarding its safety and effectiveness in these patients is limited. We conducted a 2-year post-marketing surveillance to evaluate the safety and effectiveness of infliximab in patients with intestinal BD, NBD, and VBD in Japan. This 2-year, multicenter, prospective, observational study included all patients with intestinal BD, NBD, or VBD, who had experiencedan insufficient response to conventional therapies (e.g., glucocorticoids and immunosuppressants/immunomodulators), and initiated infliximab for the first time at participating medical institutions. The safety endpoints included adverse events and adverse drug reactions (ADRs), and the effectiveness endpoints included global improvement, and for patients with acute NBD, acute attacks. Between October 2015 and August 2018, 255 patients (171 intestinal BD, 49 NBD, and 51 VBD; including 16 with two disease types) were enrolled from 133 medical centers and treated with infliximab. Adverse events, ADRs, and serious ADRs occurred in 100 (39.2%), 72 (28.2%), and 38 (14.9%) patients, respectively; incidences were generally similar across intestinal BD, NBD, and VBD groups. No new safety concerns were identified. At the final evaluation, 68.8% of patients with intestinal BD showed improvement, most patients with chronic progressive NBD and VBD had not worsened (100% and 91.7%, respectively), and 93.3% of patients with acute NBD had no new acute attacks during the observation period. These results confirmed the safety and effectiveness of infliximab in clinical practice in 255 patients with intestinal BD, NBD, and VBD. There were no new safety concerns.

The preparation of a fluorescent dual-modality nanosensor for the discrimination and determination of biothiols in real samples and its practical detection kit.

Biothiols widely exist in living organisms and have a crucial function of maintaining redox balance in the human body. It is vital yet difficult to develop probes that can simultaneously detect and distinguish biothiols. In this study, a highly sensitive dual-modality nanosensor, NBD-Nap@NCC, was developed for the discrimination and determination of biothiols in real samples, and its practical application was elucidated based on RGB analysis using a smartphone. The sensitive nanosensor was successfully prepared through the surface modification of nanocrystalline cellulose (NCC), combining NBD and naphthalene fluorophores. Owing to the high electron-withdrawing behavior of the NBD group, which led to a PET mechanism between the fluorophores, the prepared NBD-Nap@NCC nanosensor had a very weak fluorescence response. However, after treatment with Hcy or Cys, NBD-Nap@NCC quickly provided remarkable and different rates of fluorescence "turn-on" responses in both blue and green channels, which was attributed to naphthalene and NBD fluorophores as a result of the inhibition of the PET mechanism. However, after treatment with GSH, only a significant blue-channel emission, which was attributed to the naphthalene fluorophore was obtained, indicating the inhibition of the PET mechanism. Furthermore, the NCC platform demonstrated improved sensitivity and selectivity because of the increased surface area and higher number of binding sites due to modification of the NBD group on the surface. The detection limit ranged from 0.910 to 1.150 μmol L-1 for biothiols with a large dynamic response range. The accuracy of the sensor in determining the concentrations of Hcy, Cys, and GSH in real samples was evaluated via HPLC and spike/recovery analysis. Additionally, paper-based analysis kits were fabricated for the practical detection of biothiols based on RGB changes using a smartphone application.

Feasibility of a Single Pigtail Stent Made by Cutting a Nasobiliary Drainage Tube in Endoscopic Transpapillary Gallbladder Stenting for Acute Cholecystitis.

Background and objectiveIn this study, we aimed to evaluate the efficacy and safety of a single pigtail stent made by cutting a nasobiliary drainage tube (NBD stent) by comparing the clinical outcomes of using an NBD stent and those of using a ready-made double pigtail stent (RDP stent) in endoscopic gallbladder stenting (EGBS) for acute cholecystitis.Materials and methodsThis was a single-center retrospective study involving 20 cases that had technical success with EGBS for acute cholecystitis; the patients were divided into two groups: those using NBD stent (NBD group) and those using RDP stent (RDP group). The baseline characteristics and clinical outcomes were compared between the two groups.ResultsThere were 13 patients in the NBD group and seven in the RDP group. The rates of clinical success (NBD group: 92% vs. RDP group: 100%, p=0.45) did not differ significantly between the groups. Regarding adverse events, gallbladder perforation occurred in one case in the NBD group; however, no other adverse events occurred in either group (NBD group: 7.7% vs. RDP group: 0%, p=0.45). The stent patency periods did not differ significantly between the groups [NBD group: 43 (12-64) days vs. RDP group: 97 (58-215) days, p=0.17]. The stent patency period in cases of long-term stent placement after EGBS was 1,381 days and 1,579 days in the NBD group and 305 days in the RDP group, respectively.ConclusionNBD stents are considered as effective as RDP stents in EGBS for acute cholecystitis. They are highly versatile and can be used for both bridging to surgery and long-term stent placement.

Highly Selective Electrochemiluminescence Chemosensor for Sulfide Enabled by Hierarchical Reactivity

Hydrogen sulfide (H2S) is a well-known toxic gas with the odor of rotten eggs. Several reaction-based electrochemiluminescence (ECL) chemosensors for H2S have been developed; however, no homogeneous ECL probe with high selectivity toward H2S in aqueous media has been reported. Herein, we report an iridium(III) complex-based ECL chemodosimetric probe employing two 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) groups known as a photo-induced electron transfer quencher and a reaction site for the selective detection of H2S; the detection mechanism involves H2S being clearly distinguished from biothiols based on the different cleavage rates of the two NBD groups and extremely weak ECL interferences caused by reaction by-products. The probe was rationally designed to improve selectivity toward H2S within the ECL analysis platform by enabling the removal of nonspecific background signals observed via fluorescence analysis. This analytical system exhibited remarkable selectivity toward H2S, a rapid reaction rate, and high sensitivity (LOD = 57 nM) compared to conventional fluorescence methods. Furthermore, the probe could successfully quantify H2S in tap water samples and commercial ammonium sulfide solutions, which demonstrates the effectiveness of this probe in field monitoring.

Auricular nerve stimulation using the NSS-2 BRIDGE device to reduce opioid requirement following laparoscopic Roux-en-Y gastric bypass.

Evidence supports the use of complementary techniques to reduce pain and opioid use after surgery. The NSS-2 BRIDGE device (NBD; Innovative Health Solutions, Inc., Versailles, Indiana) modulates pain via stimulation of the nucleus of the auricular branch of the cranial nerves at the level of the brainstem and the limbic system. To investigate the role of auricular nerve field stimulation for pain control following gastric bypass surgery. U.S. academic medical center. A total of 18 subjects were included. Subjects were divided in 2 groups: NBD group (n = 8) and a control group (n = 10). The NBD was placed following laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery in the recovery room. The effectiveness of NBD was assessed comparing the relative use of opioid consumption (oral morphine equivalents) and pain (0 = no pain to 10= worst possible pain) at 24 and 48 hours after surgery. In addition, the device tolerability (1-10) was assessed, with 8-10 considered excellent. Data were analyzed using unpaired t tests and presented as mean ± standard deviation. Alpha was set up at .1. Compared with the control group, the use of NBD was associated with a 60.2% reduction in oral morphine equivalents (38.15 vs 15.2 mg; P < .1) and a 28% reduction in pain (5.0 vs 3.6; P = .1) at 24 hours after surgery. The tolerability of NBD was reported to be excellent. This report suggests that NBD may represent an interesting alternative to control perioperative pain and limit opioid use following bariatric surgery. This needs to be confirmed by a placebo-controlled, randomized study.

368Evaluation of myostatin as a possible regulator of the skeletal muscle-cortical bone interaction in adults

Abstract Background Bone mass was recently reported to be related to skeletal muscle mass in humans, and a decrease in cortical bone is a risk factor for osteoporosis. Since circulating myostatin is a factor that primarily controls muscle metabolism, this study examined the role of myostatin in blood in bone mass-skeletal muscle mass interactions. Methods The subjects were 375 middle-aged community residents with no history of osteoporosis or sarcopenia who participated in a health check-up. The subjects were divided into those with low cortical bone thickness (LCT) or low cancellous bone density (LBD) and those with normal values (NCT/NBD). Bone metabolism markers (BAP, TRACP-5b, etc.), skeletal muscle mass, serum myostatin levels, and lifestyle, were then compared between the groups. Results The percentage of diabetic participants and blood HbA1c, TRACP-5b, and myostatin levels were significantly higher, and the frequency of physical activity, skeletal muscle mass, grip strength, and leg strength were significantly lower in the LCT group than in the NCT group. The odds ratio of high myostatin in the LCT group compared with the NCT group was significant (2.26) even after adjusting for related factors. Significant differences were observed in the same items between the LBD and NBD groups as between the LCT and NCT groups, with no significant differences in skeletal muscle mass and serum myostatin levels. The serum myostatin level was significantly negatively correlated with cortical bone thickness and skeletal muscle mass. Conclusions Myostatin may regulate bone-skeletal muscle interactions and serve as a surrogate marker of cortical bone metabolism. Key messages The interaction between bone and skeletal muscle is reported to be important for preserving the activity of bone and muscle metabolism. Herein, we report for the first time that myostatin may regulate bone-skeletal muscle interactions and serve as a surrogate marker of cortical bone metabolism in adults.

Environment-Sensitive Fluorescence of 7-Nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-Labeled Ligands for Serotonin Receptors.

Serotonin is a neurotransmitter that plays a crucial role in the regulation of several behavioral and cognitive functions by binding to a number of different serotonin receptors present on the cell surface. We report here the synthesis and characterization of several novel fluorescent analogs of serotonin in which the fluorescent NBD (7-nitrobenz-2-oxa-1,3-diazol-4-yl) group is covalently attached to serotonin. The fluorescent ligands compete with the serotonin1A receptor specific radiolabeled agonist for binding to the receptor. Interestingly, these fluorescent ligands display a high environmental sensitivity of their fluorescence. Importantly, the human serotonin1A receptor stably expressed in CHO-K1 cells could be specifically labeled with one of the fluorescent ligands with minimal nonspecific labeling. Interestingly, we show by spectral imaging that the NBD-labeled ligand exhibits a red edge excitation shift (REES) of 29 nm when bound to the receptor, implying that it is localized in a restricted microenvironment. Taken together, our results show that NBD-labeled serotonin analogs offer an attractive fluorescent approach for elucidating the molecular environment of the serotonin binding site in serotonin receptors. In view of the multiple roles played by the serotonergic systems in the central and peripheral nervous systems, these fluorescent ligands would be useful in future studies involving serotonin receptors.

Characterization of Hysterectomy in Women with VWD Using Data from a US Medical Claims Database

Background: Von Willebrand disease (VWD) is the most common inherited bleeding disorder in women. Heavy menstrual bleeding (HMB) is a frequent symptom with a significant impact on the quality of life, but its management is complicated by delayed recognition and diagnosis of VWD. Hysterectomy or uterine ablation (UA) may be performed for refractory HMB, but has profound consequences for women, particularly those of child-bearing age. Objective: To assess rates of hysterectomy/ UA in women before and after diagnosis of VWD, and evaluate hysterectomy/UA (including age at procedure) in women with VWD compared to women without a bleeding disorder, using medical claims data. Methods: We analyzed data from subjects enrolled in the IMS PharMetrics Plus Database of medical insurance claims between July 2013 and June 2015. Data were extracted for female subjects with diagnosed VWD (defined as ≥2 medical claims for VWD [ICD-9 code 286.4]), and for a sample of 10,000 "no bleeding disorder [NBD]" subjects (no history of a bleeding disorder via medical claim or of product use for any bleeding disorder). Occurrence of hysterectomy/UA was compared in the following populations, with time periods aligned to cover the most recent year: VWD patients with continuous enrollment (CE) in the most recent year (N=5257) and NBD patients with CE in the most recent 2 years (N=5673). A VWD subpopulation with enrollment in the 2 years before and after diagnosis (N=1181) was used for analysis of hysterectomy/UA rates pre- and post- diagnosis. Age at hysterectomy/UA was analyzed for patients with CE for 1 year before and after their procedure. Bleed claims in the 1 year before and the 6 to 18 months after hysterectomy/UA were analyzed for patients with CE over this timeframe. Groups were compared using the t-test (mean age at hysterectomy) and Chi-squared test (other outcomes). Results: More women without a bleeding disorder (NBD group) than with VWD had undergone hysterectomy or UA within the most recent year (105/5673 [1.9%] versus 60/5257 [1.1%]; P=0.0024). Among women with VWD, the rate of hysterectomy/UA was higher after VWD diagnosis than before (69/1181 [5.8%] versus 41/1181 [3.5%] women; P=0.0063). When evaluating women with 1 year of enrollment before and after the procedure, 246 (VWD) and 578 (NBD) women with hysterectomy/UA were identified. Among these women with VWD and NBD, there was no significant difference in mean age at hysterectomy/UA (41 versus 43 years; P=0.9997). However, a significantly greater proportion of women with hysterectomy/UA in the VWD compared with the NBD group were aged ≤40 years (110/246 [44.7%] versus 208/578 [36.0%], P=0.0185), and ≤35 years (58/246 [23.6%] versus 86/578 [14.9%]; P=0.0026). Claims for all bleeds (including HMB) were significantly reduced following hysterectomy/UA, but some patients continued to bleed. Among women with VWD, 200/226 (88.5%) and 48/226 (21.2%) had bleed claims before and after the procedure, respectively (P&amp;lt;0.0001), as did 404/531 (76.1%) and 41/531 (7.7%) of women with NBD (P&amp;lt;0.0001). Of the 48 women with VWD who had bleed claims following their procedure, 37 (77.1%) had claims for HMB. Bleed claims were significantly more common among women with VWD than with NBD, both before and after hysterectomy/UA (both P&amp;lt;0.0001). Conclusions: Surprisingly, rates of hysterectomy/UA increased among women with VWD following their diagnosis. Among women who underwent hysterectomy/UA, those with VWD were on average younger than those with NBD. Despite the perception of hysterectomy/UA as an effective treatment for HMB, our analysis indicates around one in five women with VWD may continue to have HMB bleed claims after this procedure. These data underscore a significant need for improved and optimized treatment in women with VWD, to control HMB and other bleeding episodes, and to prevent or delay hysterectomy/UA. Disclosures Sidonio: Bayer, Bioverativ/Sanofi, Novo Nordisk, Takeda, Uniqure, Biomarin, Octapharma, Catalyst, Grifols, Sigilon, Tremeau, Genentech/Roche: Consultancy; Octapharma, Grifols, Takeda and Genentech: Research Funding. Hale:Takeda Pharmaceutical Company Limited: Current Employment. Halari:Charles River Associates: Current Employment.

&lt;i&gt;In silico&lt;/i&gt; analysis of interaction of compounds, containing photoactivatable groups,with human CYP7 enzymes

In silico analysis of “protein-ligand” complexes of human CYP7 enzymes with modified borondipyrrome-tene (BODIPY) and steroids, containing photo-activated crosslinking groups, wasperformed in order to identify structural peculiarities of their interaction. It was found that BODIPY molecules and DHEA derivative with diazirine group are able to bind tightly with human steroid-hydroxylases. Binding affinity is comparable with corresponding values for essential ligands of the enzymes. Binding mode of the modified steroid corresponds to the binding mode of essential CYP7 ligands, so formation of hydroxylated products is possible. It was found that presence of both diazirine and NBD groups in a molecule significantly increases affinity of the compound in case of CYP7A1 and, especially, CYP7B1. Amino acid residues, located in a close proximity with photo-activated groups were detected, that can form covalent adducts with them. The obtained results can shed light on the mechanism of interaction of the compounds with recombinant human CYP7 enzymes in vitro. The results can also be used for the identification of modified amino acids of the proteins that are formed under photoactivation of the compounds in vitro.

A Systematic Review of Neurocognitive Functioning in Behçet's Disease.

Behçet's disease (BD) is a vascular, inflammatory multisystem disorder with neuro-Behçet's (NBD) diagnosed in a subset of patients with neurological manifestations. The objective of this review was to determine whether neurocognitive dysfunction is observed in BD, in which neurocognitive domains, and whether there are differences in rates of dysfunction observed between BD and NBD groups. Studies of any methodology were included that reported results from standardized neurocognitive assessment measures in participants with BD or NBD. Twelve group comparison studies met the criteria for inclusion in the review (totalling 284 BD and 157 NBD participants), as well as 17 case study/series papers (11 BD, 35 NBD). Issues with blinding, incomplete data reporting and selective reporting bias were found across the group and case study/series papers, as well as inadequate statistical adjustment for multiple comparisons in the group studies, and the lack of the use of appropriate norms or adjustment for premorbid ability in the case series/studies papers. These quality issues impacted on the conclusions that could be drawn from the current literature. Neurocognitive dysfunction was found in NBD compared to health controls (HC) in a higher proportion of results across studies, than in comparisons between BD and HC groups. The domains in which neurocognitive attenuation was most often reported were visual spatial ability, working memory and acquired knowledge, with more than 25% of these results showing significantly lower functioning in both the BD and NBD groups compared to HC. More than 25% of the processing speed and long-term memory encoding and retrieval results were also lower for the NBD group, compared to HC. Group comparisons between NBD and multiple sclerosis participants indicated few significant differences in neurocognitive test results. The majority of case study/series participants were found to have some degree of attenuated neurocognitive functioning, as defined by case study/series authors.

Effect of Acyl Chain Length on the Rate of Phospholipid Flip-Flop and Intermembrane Transfer.

The rate at which phospholipids equilibrate between different membranes and between the non-polar environments in biological fluids is of high importance in the understanding of biomembrane diversity, as well as in the development of liposomes for drug delivery. In this work, we characterize the rate of insertion into and desorption from POPC bilayers for a homologous series of amphiphiles with the fluorescent NBD group attached to phosphoethanolamines of different acyl chain lengths, NBD-diC n -PE with n = 6, 8, 10, and 12. The rate of translocation between bilayer leaflets was also characterized, providing all the relevant parameters for their interaction with lipid bilayers. The results are complemented with data for NBD-diC14-PE obtained from literature (Abreu et al. Biophys J 87:353-365, 2004; Moreno et al. Biophys J 91:873-881, 2006). The rate of translocation between the POPC leaflets is not dependent on the length of the acyl chains, while this affects strongly the rate of desorption from the bilayer. Insertion in the POPC bilayer is not diffusion controlled showing a significant dependence on the acyl chain length and on temperature. The results obtained are compared with those previously reported for NBD-LysoC14-PE (Sampaio et al. Biophys J 88:4064-4071, 2005), and with the homologous series of single chain amphiphiles NBD-C n (Cardoso et al. J Phys Chem B 114:16337-16346, 2010; J Phys Chem B 115:10098-10108, 2011). This allows the establishment of important relations between the rate constants for interaction with the lipid bilayers and the structural properties of the amphiphiles, namely the total surface and the cross-section of their non-polar region.

Influence of metal cations and cholesterol on lipid-amphotericin membrane

Amphotericin B(AmB) has been widely used in antifungal therapy. AmB molecules combine with cholesterol to form pores that can be toxic to human cells, thus greatly limiting its clinical application. The interaction between AmB and the cell membrane may be influenced by potassium, sodium and calcium ions. In this study, the bilayer in large unilamellar lipid-drug liposomes with or without cholesterol was employed as a model membrane. N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine(NBD-PE) and 1-palmitoyl-2-[6-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)aminodoclecanoyl]-sn-glysero-3-phosphocholine(6-NBD-PC) are two kinds of fluorescent lipid probes, and the NBD group is attached to the polar lipid headgroup in the former, but to the sn-2 fatty acyl chain in the latter. The effect of these metal cations on the lipid-drug membrane was monitored by red edge excitation shift(REES), fluorescence polarization, and the fluorescence lifetime of lipid probes in hydrophilic and hydrophobic areas of the membrane. These ions have different effects on the lipid-AmB membrane. Cholesterol can strengthen the packing ability of the membrane, which is influenced differently by potassium, sodium and calcium ions. Moreover, the influence of these ions on the membrane may be relative to the method of ion transportation through the membrane. This study is significant to understand the reduction of AmB’s cellular toxicity.

Alkyl-substituted phenylamino derivatives of 7-nitrobenz-2-oxa-1,3-diazole as uncouplers of oxidative phosphorylation and antibacterial agents: involvement of membrane proteins in the uncoupling action

In search for new effective uncouplers of oxidative phosphorylation, we studied 4-aryl amino derivatives of a fluorescent group 7-nitrobenz-2-oxa-1,3-diazol (NBD). In our recent work (Denisov et al., Bioelectrochemistry, 2014), NBD-conjugated alkyl amines (NBD-Cn) were shown to exhibit uncoupling activity. It was concluded that despite a pKa value being about 10, the expected hindering of the uncoupling activity could be overcome by insertion of an alkyl chain. There is evidence in the literature that the introduction of an aryl substituent in the 4-amino NBD group shifts the pKa to neutral values. Here we report the data on the properties of a number of 4-arylamino derivatives of NBD, namely, alkylphenyl-amino-NBD (Cn-phenyl-NBD) with varying alkyl chain Cn. By measuring the electrical current across planar bilayer lipid membrane, the protonophoric activity of Cn-phenyl-NBD at neutral pH grew monotonously from C1- to C6-phenyl-NBD. All of these compounds increased the respiration rate and reduced the membrane potential of isolated rat liver mitochondria. Importantly, the uncoupling action of C6- and C4-phenyl-NBD was partially reversed by glutamate, diethyl pyrocarbonate (DEPC), 6-ketocholestanol, and carboxyatractyloside, thus pointing to the involvement of membrane proteins in the uncoupling activity of Cn-phenyl-NBD in mitochondria. The pronounced recoupling effect of DEPC, an inhibitor of an aspartate–glutamate carrier (AGC), and that of its substrates for the first time highlighted AGC participation in the action of potent uncouplers on mitochondria. C6-phenyl-NBD produced strong antimicrobial effect on Bacillus subtilis, which manifested itself in cell membrane depolarization and suppression of bacterial growth at submicromolar concentrations.

Physical Activity Level of Post-menopausal Women with Low Bone Mineral Density.

Introduction Proper physical activity is related to the prevention and the treatment of osteoporosis. Purpose To assess the level of physical activity (PA) in post-menopausal women with low bone mineral density (BMD). Methods This cross-sectional clinical study included 123 post-menopausal women. The inclusion criteria were: age of ≥ 45 years with last menses at least 12 months prior to the initiation of the study, and bone density scan (BDS) values measured over the preceding 12 months. Women with severe osteoarthritis were excluded. Women were allocated into three groups, according to BMD measured by BDS [osteoporosis (OP; 54 women), osteopenia (35 women), and normal bone density (NBD; 35 women)], and compared for general, clinical, and anthropometric data, and for PA level. The latter was assessed using the International Physical Activity Questionnaire (IPAQ), in metabolic equivalent of task (MET) units. Participants were classified as sedentary, active or very active. Quantitative variables were compared using ANOVA followed by Tukey's test. Associations between qualitative variables were tested by Chi-square (χ2) or Fisher's exact test. In order to check for differences among groups and IPAQ domains, a generalized linear model with Gamma distribution was adjusted for values in METs. Results The OP group differed from the NBD group regarding age (61.8 ± 10.1 and 52.9 ± 5.4 years), percentage of participants with self-declared white ethnicity (43.9 and 28.0%), body mass index (BMI - 25.7 ± 5.4 and 30.9 ± 5.1 kg/m(2)), and time since menopause (15.5 ± 7.5 and 5.8 ± 4.5 years). Smoking rates were higher in the OP (55.6%) and NBD groups (33.3%) than in the osteopenia group (11.1%). Within the OP group, the rate of subjects with sedentary lifestyles was higher (42.6%), and time spent sitting was greater (344.3 ± 204.8 METs) than in the groups with osteopenia (20.0% and 300.9 ± 230.6 METs) and NBD (17.7% and 303.2 ± 187.9 METs). Conclusions The rate of sedentary lifestyles was higher in post-menopausal women with OP than in those with either osteopenia or NBD. In order to change this physical inactivity profile, strategies should be created to address this group of patients.

Conformationally switchable water-soluble fluorescent bischolate foldamers as membrane-curvature sensors.

Membrane curvature is an important parameter in biological processes such as cellular movement, division, and vesicle fusion and budding. Traditionally, only proteins and protein-derived peptides have been used as sensors for membrane curvature. Three water-soluble bischolate foldamers were synthesized, all labeled with an environmentally sensitive fluorophore to report their binding with lipid membranes. The orientation and ionic nature of the fluorescent label were found to be particularly important in their performance as membrane-curvature sensors. The bischolate with an NBD group in the hydrophilic α-face of the cholate outperformed the other two analogues as a membrane-curvature sensor and responded additionally to the lipid composition including the amounts of cholesterol and anionic lipids in the membranes.

Rationally-designed fluorescent lysine riboswitch probes

Two fluorescent lysine amide analogs, in which the carboxyl end of lysine was covalently attached to dansyl or NBD groups through an ethylene glycol-based linker, were rationally designed and synthesized. Both probes showed high binding affinity to the lysine riboswitch in vitro and their fluorescence intensities decreased by riboswitch binding.

Improved synthesis of 4-amino-7-nitrobenz-2,1,3-oxadiazoles using NBD fluoride (NBD-F)

The 7-nitrobenz-2,1,3-oxadiazole (NBD) unit is a highly useful fluorescent tag with wide application in biology. Installation of the NBD group typically proceeds via the SNAr reaction between an amine and an NBD halide. Herein, we demonstrate that NBD-F 1 results in significantly higher yields than NBD-Cl 2, and that triethylamine in dimethylformamide at 23°C overnight is a broadly applicable set of conditions for this reaction. In particular, the highly useful fluorescent carbohydrate 2-NBD-glucosamine (2-NBDG, 3) can now be prepared in 75% yield with NBD-F as compared to 12% with NBD-Cl.

Chain Length Effect on the Binding of Amphiphiles to Serum Albumin and to POPC Bilayers

The interaction of small molecules, such as drugs or metabolites, with proteins and biomembranes is of fundamental importance for their bioavailability. The systematic characterization of the binding affinity for structurally related ligands may provide rules that allow its prediction for any other relevant molecule. In this work we have studied a homologous series of fluorescent fatty amines with the fluorescent moiety 7-nitrobenz-2-oxa-1,3-diazol-4-yl covalently bound to the amine group (NBD-C(n); n = 4, 6, 8, 10, 12, 14, and 16) in aqueous solution and associated with BSA or lipid bilayers. We have found a linear dependence with the length of the alkyl chain, up to NBD-C(10), for the Gibb's free energy of partition between the aqueous solution and 1-palmitoyl-2-oleoyl phosphatidylcholine bilayers equal to ΔΔG = -2.5 ± 0.3 kJ/mol per methylene group. Additionally, the amphiphiles interacted efficiently with bovine serum albumin, and it was inhibited by fatty acids indicating that binding occurs to the fatty acids highest affinity binding site. The association of the amphiphiles with BSA and POPC bilayers was performed at different temperatures (15-35 °C) allowing for the calculation of the enthalpic and entropic contributions. A value of ΔH = -15 ± 4 kJ/mol was obtained for all amphiphiles and binding agents. The entropy contribution was always positive and increased with the length of the alkyl chain. The location of the ligand in the biological membrane is also of high relevance, namely because this will determine its effect on biomembrane properties at high ligand concentrations. With this goal, we have measured some photophysical properties of the amphiphiles inserted in POPC bilayers, and we found no significant variation along the series, indicating that the NBD group is located in a region with similar properties regardless of the length of the nonpolar group. An exception was noted for the case of NBD-C(14) whose parameters were somewhat different from the trend observed.

Characterization of a Homologous Series of Fluorescent Fatty Amines. Photophysics, Aqueous Solubility and Binding to Albumin and to POPC Bilayers

The 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) is a small and very polar group whose fluorescence quantum yield strongly depends on the polarity of its environment. When bound to the polar headgroup of lipid molecules it allows the characterization of the structure and dynamics of lipid bilayers. The solvent dependence of its fluorescence has been exploited by this research group to characterize the kinetics and thermodynamics of the interaction of different amphiphiles with lipid bilayers and proteins.In this work we report on the synthesis and characterization of a homologous series of fluorescent fatty amines (NBD-Cn; n=4, 6, 8, 10, 12, 14 and 16). At 25°C and pH=7.4, the critical aggregation concentration (CAC) in aqueous media range from 2x10−4 M for NBD-C4 to 4x10−9 M for NBD-C12. The partition coefficient to lipid bilayers prepared from 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) was also measured for the amphiphiles with a CAC>20 nM (NBD-C4 to NBD-C10) and ranged from 9.5x102 to 3.6x105, with a ΔΔG=-4.9±0.5 kJ/mol per ethyl group. The amphiphiles interacted efficiently with Bovine Serum Albumin (KB=1.7x104 and 7.9x106 M−1 for NBD-C4 and NBD-C10 respectively) and this was inhibited by fatty acids indicating that binding occurs essentially in the same binding site.Some photophysical properties of the amphiphiles in POPC bilayers were also measured and we found no significant variation along the series indicating that the NBD group is located in a region with the same properties regardless of the length of the non-polar group. An exception was noted for the case of NBD-C14 that showed somewhat smaller fluorescence anisotropy. The amphiphiles lifetime decay observed was mono-exponential in water or methanol but when inserted in POPC bilayers a bi-exponential law was required.