7-Methoxy-13-dehydroxypaxilline: New indole diterpenoid from an endophytic fungus Penicillium sp. Nb 19.

ABSTACTA chemical investigation of the endophyte Penicillium sp. Nb 19, isolated from leaves of the traditionally medical plant Baphicacanthus cusia (Nees) Bremek., yielded one new indole diterpenoid, 7-methoxy-13-dehydroxypaxilline (1) together with seven known metabolites (2-8). The obtained structure of compound 1 was elucidated by its spectroscopic data. In addition, the absolute configuration of compound 6 was confirmed by ECD for the first time. Compounds 1-6 were evaluated for antitumor activity against MCF-7, HepG2, and HCCC-9810 cell lines.

Nanobody-based trispecific T cell engager (Nb-TriTE) enhances therapeutic efficacy by overcoming tumor-mediated immunosuppression.

BACKGROUND: T cell engagers (TCEs) have been established as an emerging modality for hematologic malignancies, but solid tumors remain refractory. However, the upregulation of programmed cell death 1 (PD-1) is correlated with T cell dysfunction that confer tumor-mediated immunosuppression. Developing a novel nanobody-based trispecific T cell engager (Nb-TriTE) would be a potential strategy to improve therapeutic efficacy. METHODS: Given the therapeutic potential of nanobodies (Nbs), we first screened Nb targeting fibroblast activation protein (FAP) and successfully generated a Nb-based bispecific T cell engager (Nb-BiTE) targeting FAP. Then, we developed a Nb-TriTE by fusing an anti-PD-1 Nb to the Nb-BiTE. The biological activity and antitumor efficacy of the Nb-TriTE were evaluated in vitro and in both cell line-derived and patient-derived xenograft mouse models. RESULTS: We had for the first time successfully selected a FAP Nb for the generation of novel Nb-BiTE and Nb-TriTE, which showed good binding ability to their targets. Nb-TriTE not only induced robust tumor antigen-specific killing, potent T cell activation and enhanced T cell function in vitro, but also suppressed tumor growth, improved survival and mediated more T cell infiltration than Nb-BiTE in mouse models of different solid tumors without toxicity. CONCLUSIONS: This novel Nb-TriTE provides a promising and universal platform to overcome tumor-mediated immunosuppression and improve patient outcomes in the future.

Interfacial Modeling of Fibrinogen Adsorption onto LiNbO3 Single Crystal-Single Domain Surfaces.

For the development of next-generation protein-based biosensor surfaces, it is important to understand how functional proteins, such as fibrinogen (FBG), interact with polar substrate surfaces in order to prepare highly sensitive points of medical care diagnostics. FBG, which is a fibrous protein with an extracellular matrix, has both positively and negatively charged regions on its 3-dimensional surface, which makes interpreting how it effectively binds to polarized surfaces challenging. In this study, single-crystal LiNbO3 (LNO) substrates that have surface charges were used to investigate the adsorption of FBG protruding polar fragments on the positively and negatively charged LNO surfaces. We performed a combination of experiments and multi-scale molecular modeling to understand the binding of FBG in vacuum and water-solvated surfaces of LNO. XPS measurements showed that the FBG adsorption on LNO increased with increment in solution concentration on surfaces independent of charges. Multi-scale molecular modeling employing Quantum Mechanics, Monte Carlo, and Molecular Mechanics addressed the phenomenon of FBG fragment bonding on LNO surfaces. The binding simulation validated the experimental observation using zeta potential measurements which showed presence of solvated medium influenced the adsorption phenomenon due to the negative surface potential.

Implanting Niobium Carbide into Trichoderma Spore Carbon: a New Advanced Host for Sulfur Cathodes.

Tailored construction of advanced carbon hosts is playing a great role in the development of high-performance lithium-sulfur batteries (LSBs). Herein, a novel N,P-codoped trichoderma spore carbon (TSC) with a bowl structure, prepared by a "trichoderma bioreactor" and annealing process is reported. Moreover, TSC shows excellent compatibility with conductive niobium carbide (NbC), which is in situ implanted into the TSC matrix in the form of nanoparticles forming a highly porous TSC/NbC host. Importantly, NbC plays a dual role in TSC for not only pore formation but also enhancement of conductivity. Excitingly, the sulfur can be well accommodated in the TSC/NbC host forming a high-performance TSC/NbC-S cathode, which exhibits greatly enhanced rate performance (810 mAh g-1 at 5 C) and long cycling life (937.9 mAh g-1 at 0.1 C after 500 cycles), superior to TSC-S and other carbon/S counterparts due to the larger porosity, higher conductivity, and better synergetic trapping effect for the soluble polysulfide intermediate. The synergetic work of porous the conductive architecture, heterodoped N&P polar sites in TSC and polar conductive NbC provides new opportunities for enhancing physisorption and chemisorption of polysulfides leading to higher capacity and better rate capability.

Effects of niobium ions released from calcium phosphate invert glasses containing Nb2O5 on osteoblast-like cell functions.

The effects of niobium ions released from 60CaO-30P(2)O(5)-(10-x)Na(2)O-xNb(2)O(5) (mol %, x = 0-10) glasses on MC3T3-E1 cell functions were evaluated by culture tests with two systems; cell culture on glass plates, or in culture media containing glass extracts. Alkaline phosphatase (ALP) activity in the cells cultured on the glass plates containing 3 and 5 mol % of Nb(2)O(5) was significantly higher than that on the Nb(2)O(5)-free glass, although proliferation was not enhanced on all glasses containing Nb(2)O(5). Cells cultured in the medium containing 3 × 10(-7) M niobium ions showed the highest ALP activity in comparison with other Nb-containing media or normal medium, regardless of the presence of osteogenic factors (ascorbic acid, ß-glycerophosphate and dexamethasone) in the media. Calcium deposition by the cells cultured in the medium containing 3 × 10(-7) M niobium ions was twice as high as those cultured in medium containing no niobium ions. The effects of niobium ions were thought to depend on ion concentration, and to enhance differentiation and mineralization of osteogenic cells rather than their initial adhesion or proliferation.

"Docking sites": nanometer-scale organization of a reactive, protein-resistant, graft copolymer-based interface for macromolecule immobilization.

The signal-to-noise ratio of a sensor system is determined by the affinity of its active component for the analyte on one hand and its inertness with respect to unrelated stimuli (noise) on the other hand. Nonspecific interactions between the environment and biosensor components (typically constructed from glass, silica, or transition metal oxides) result in nonspecific adsorption onto the latter and constitute a major source of noise. We have previously introduced a polymeric interface for preventing nonspecific adsorption while allowing for high-affinity, specific interactions. It is based on the coassembly of biotinylated and nonbiotinylated poly(l-lysine)-graft-poly(ethylene glycol) from aqueous solutions to negatively charged surfaces, such as Nb(2)O(5). In this study, we investigated by atomic force microscopy the nanoscale organization of this interface for each individual step involved in the preparation of a bioactive interface: polymer adsorption, loading with streptavidin, and binding of biotinylated vesicles.

Spectrophotometric determination of urinary protein with o-sulfophenylfluorone-metal complex.

A simple and sensitive spectrophotometric method for the determination of human serum albumin (HSA) was established based on the ternary complex-formation reaction of HSA with o-sulfophenylfluorone (SPF) as a xanthene dye and metal ion (niobium(V) and bismuth(III)) in the presence of a dispersion agent. This new method enabled the determination of HSA in the range of 1 - 15 microg/ml HSA by measuring the difference of the absorbance at 530 nm between HSA-SPF-metal ion and SPF-metal ion solutions. In the determination of HSA, this method is about 2-times more sensitive than the Pyrogallol Red-molybdenum(VI) method (PR method), which accounts for more than 80% of the quantification methods for urinary protein assays in Japan. There was no significant difference between the results obtained by the present method and the PR method for human urine samples. The binding process between the SPF-metal complex and HSA was studied by determining the binding parameters and the thermodynamic parameters.

Intracellular mapping of the distribution of metals derived from the antitumor metallocenes.

The intracellular distribution of transition metals in V79 Chinese hamster lung cells treated with subtoxic doses of the organometallic anticancer complexes Cp(2)MCl(2), where Cp is eta (5) -cyclopentadienyl and M is Mo, Nb, Ti, or V, has been studied by synchrotron-based X-ray fluorescence (XRF). While significantly higher concentrations of Mo and Nb were found in treated cells compared with control cells, distinct differences in the cellular distribution of each metal were observed. Analysis of thin sections of cells was consistent with some localization of Mo in the nucleus. Studies with a noncytotoxic thiol derivative of molybdocene dichloride showed an uneven distribution of Mo in the cells. For comparison, the low levels of Ti and V in cells treated with the more toxic titanocene and vanadocene complexes, respectively, resulted in metal concentrations at the detection limit of XRF. The results agree with independent chemical studies that have concluded that the biological chemistry of each of the metallocene dihalides is unique.

A re-evaluation of the biokinetics of zirconium in humans.

There is much interest in understanding the biokinetics of zirconium in humans due to the potential radiological risk represented by the radionuclide 95Zr and by its daughter 95Nb. Despite the significance of zirconium, few data are available on the actual biokinetics of zirconium in humans. Accordingly the biokinetic model currently recommended by ICRP for this element is based mainly on data from animal experiments. In this study, the use of the stable isotopes 90Zr and 96Zr as tracers has enabled the conduct of 6 biokinetic investigations in 3 healthy volunteers. These studies have provided new valuable information about intestinal absorption and kinetics in blood plasma of zirconium and have been used for the set-up of a more realistic compartmental model with possible applications for dosimetric purposes.

Complex behavior of self-propagating reaction waves in heterogeneous media.

Self-propagating high temperature reaction waves, leading to the synthesis of advanced materials, are investigated in a variety of heterogeneous reaction systems by using a digital high-speed microscopic video recording technique. It is shown that, although on the macroscopic length and time scales, the reaction appears to move in a steady mode, on the microscopic level it has a complex character that is related to the reaction mechanism.

Wear-resistant, hemocompatible Ti-Nb-Zr and Zr-Nb alloys to improve blood pump design and performance.

Over the past several years, we have developed novel titanium-niobium-zirconium (Ti-Nb-Zr) alloys to address the long-term performance needs of orthopedic implants. The unique properties of these alloys also render them promising candidates for blood pumps. These properties include excellent biocompatibility in combination with high strength and toughness, and low elastic modulus (low stiffness). Additionally, these metal alloys are readily hot or cold worked into complex shapes including wire, foil, tubing and bar. They are readily machined and polished, and they can be surface oxidized to form a hard, wear-resistant, low-friction ceramic surface layer. In this diffusion-hardened condition, oxygen also hardens the underlying metal to optimize the bone between the ceramic oxide surface and the tough metal substrate. Unlike metal surfaces, oxidative wear, which can alter surface energy, friction, and hemocompatibility, does not occur. Consequently, the combined benefits of a stable, wear-resistant, low-friction ceramic surface layer with the toughness, strength, formability, and thermal conductivity of metal may provide improvements in the design and performance of blood pumps and peripheral graft and percutaneous (power) components of the pump.

Selective intra-lysosomal concentration of niobium in kidney and bone marrow cells: a microanalytical study.

Niobium is used as an alloy in the industrial and biomedical fields. The concentration of the toxic element in organs of a number of animal species has been defined by using radioactive niobium (95Nb). However, tissue lesions induced by niobium have only been studied at the light microscopy level. In this study, we used an electron probe X-ray analyzer equipped with a transmission electron microscope to define the localization of this element in kidney and bone marrow cells. Results demonstrated that niobium is located in the lysosome and that this element coprecipitates with phosphate. In kidney, lysosomes and precipitates are eliminated in the tubular lumen. In contrast, precipitates appear to be eliminated more slowly from the lysosomes of bone marrow macrophages. These processes therefore correspond to one of the mechanisms by which lysosomes eliminate certain toxic mineral elements and thus play a role in the more general process of the body's defenses.

Exposure to metals that have recently come into use.

The possibility of deriving normal biological values for some rare metals is investigated. The metals under study are gallium, germanium, indium, niobium and tellurium, i.e. a group of metals with increasing utilization in the electronics industry. So far some data are unavailable for some of the elements, e.g. daily intake, oral absorption and half-life time for gallium, and body burden for gallium and germanium. Reliable values of blood concentration are available only for gallium, niobium and tellurium. The problem related to a proposed urinary biological limit value for tellurium is also discussed.

Effect of mixed ligand complex therapy on the retention of 95Nb and 144Ce in mice.

We have examined in mice the effects of mixed ligand treatments with desferrioxamine B (DFOA), Na3Ca-diethylenetriamine pentaacetic acid (DTPA), and DL-penicillamine (PA) on the retention of a mixture of 95Nb and 144Ce. The results show that 95Nb + 144Ce could be mobilized effectively by simultaneous application of specific agents (i.e., DFOA, DTPA) with no decrease in their efficiencies.

Comparative distribution on niobium-95 in maternal and fetal rats and rabbits.

Pregnant rats and rabbits were injected with Nb95 towards the end of gestation. In rats, all maternal tissues showed higher concentrations compared to the fetal organs; the highest ratio was 0.6 in bone. In rabbits a different distribution was found. The fetal bone exhibited a 3.5 times higher concentration of Nb95 than the maternal one.

Transfer and distribution of niobium-95 in adult, fetal, and newborn rats after injection during pregnancy.

Following i.v. injection of Nb-95 into pregnant rats, fetuses and newborns were dissected and measured for radioactivity after several time intervals. At any time only a small quantity of the administered radioactivity was transferred to fetus and newborn and the fetal tissue concentrations were always lower than the maternal ones. The highest ratio (0.6) between fetal and maternal tissue concentrations was found in bone.

The reactivity of the thiol groups of the adenosine triphosphatase of sarcoplasmic reticulum and their location on tryptic fragments of the molecule.

The ATPase (adenosine triphosphatase) from sarcoplasmic reticulum contains 20 thiol groups/115000 daltons, measured by using either N-ethyl[(14)C]maleimide or 5,5'-dithiobis-(2-nitrobenzoate) in sodium dodecyl sulphate. After reduction there were 26 thiol groups, in good agreement with 26.5 residues of cysteic acid found by amino acid analysis. The difference between this and the 20 residues measured before reduction implies the presence of three disulphide residues. The same number of disulphide residues was found by direct measurement. Three to six fewer thiol groups were found in preparations made in the absence of dithiothreitol. The missing residues were accounted for as cysteic acid. The distribution of disulphide bonds and of exposed and buried thiol groups among the tryptic fragments of the molecule was measured after labelling with N-ethyl[(14)C]-maleimide. The disulphides were confined to fragment B (mol.wt. 55000), whereas several thiol groups were present on each of the fragments (A, B, A(1) and A(2)). The kinetics of the reaction of the ATPase with 5,5'-dithiobis-(2-nitrobenzoate) showed that four or five of the thiol groups were unreactive in the absence of detergent and that 13 of the remainder reacted with a single first-order rate constant. In the presence of ATP and Ca(2+) the reaction rate of all but two groups of this class was uniformly decreased. In the presence or absence of ATP and Ca(2+) the rate constant for inactivation was close to the rate constant for this class, but was not identical with it. No selective protection of a specific active-site-thiol group was observed. Parallel experiments with sarcoplasmic reticulum gave similar results, except that the reaction rates were a little lower and there were two more buried groups. Solution of ATPase of sarcoplasmic reticulum in detergent greatly increased the reactivity of all thiol groups. The effects of low concentrations of deoxycholate were reversible. EGTA or low concentrations (0.02mm) of Ca(2+) of Mg(2+) had very little effect on the reactivity.