Blood pressure reduction does not reduce perihematoma oxygenation: a CT perfusion study

Blood pressure (BP) reduction after intracerebral hemorrhage (ICH) is controversial, because of concerns that this may cause critical reductions in perihematoma perfusion and thereby precipitate tissue damage. We tested the hypothesis that BP reduction reduces perihematoma tissue oxygenation.Acute ICH patients were randomized to a systolic BP target of <150 or <180 mm Hg. Patients underwent CT perfusion (CTP) imaging 2 hours after randomization. Maps of cerebral blood flow (CBF), maximum oxygen extraction fraction (OEF^max), and the resulting maximum cerebral metabolic rate of oxygen (CMRO₂^max) permitted by local hemodynamics, were calculated from raw CTP data.Sixty-five patients (median (interquartile range) age 70 (20)) were imaged at a median (interquartile range) time from onset to CTP of 9.8 (13.6) hours. Mean OEF^max was elevated in the perihematoma region (0.44±0.12) relative to contralateral tissue (0.36±0.11; P<0.001). Perihematoma CMRO₂^max (3.40±1.67 mL/100 g per minute) was slightly lower relative to contralateral tissue (3.63±1.66 mL/100 g per minute; P=0.025). Despite a significant difference in systolic BP between the aggressive (140.5±18.7 mm Hg) and conservative (163.0±10.6 mm Hg; P<0.001) treatment groups, perihematoma CBF was unaffected (37.2±11.9 versus 35.8±9.6 mL/100 g per minute; P=0.307). Similarly, aggressive BP treatment did not affect perihematoma OEF^max (0.43±0.12 versus 0.45±0.11; P=0.232) or CMRO₂^max (3.16±1.66 versus 3.68±1.85 mL/100 g per minute; P=0.857). Blood pressure reduction does not affect perihematoma oxygen delivery. These data support the safety of early aggressive BP treatment in ICH.     

Physiological and Brain Activity After a Combined Cognitive Behavioral Treatment Plus Video Game Therapy for Emotional Regulation in Bulimia Nervosa: A Case Report

Background

PlayMancer is a video game designed to increase emotional regulation and reduce general impulsive behaviors, by training to decrease arousal and improve decision-making and planning. We have previously demonstrated the usefulness of PlayMancer in reducing impulsivity and improving emotional regulation in bulimia nervosa (BN) patients. However, whether these improvements are actually translated into brain changes remains unclear.

Objective

The aim of this case study was to report on a 28-year-old Spanish woman with BN, and to examine changes in physiological variables and brain activity after a combined treatment of video game therapy (VGT) and cognitive behavioral therapy (CBT).

Methods

Ten VGT sessions were carried out on a weekly basis. Anxiety, physiological, and impulsivity measurements were recorded. The patient was scanned in a 1.5-T magnetic resonance scanner, prior to and after the 10-week VGT/CBT combined treatment, using two paradigms: (1) an emotional face-matching task, and (2) a multi-source interference task (MSIT).

Results

Upon completing the treatment, a decrease in average heart rate was observed. The functional magnetic resonance imaging (fMRI) results indicated a post-treatment reduction in reaction time along with high accuracy. The patient engaged areas typically active in healthy controls, although the cluster extension of the active areas decreased after the combined treatment.

Conclusions

These results suggest a global improvement in emotional regulation and impulsivity control after the VGT therapy in BN, demonstrated by both physiological and neural changes. These promising results suggest that a combined treatment of CBT and VGT might lead to functional cerebral changes that ultimately translate into better cognitive and emotional performances.     

Assembly of iron oxide nanosheets at the air–water interface by leucine–histidine peptides

The fabrication of inorganic nanomaterials is important for a wide range of disciplines. While many purely inorganic synthetic routes have enabled a manifold of nanostructures under well-controlled conditions, organisms have the ability to synthesize structures under ambient conditions. For example, magnetotactic bacteria, can synthesize tiny ‘compass needles’ of magnetite (Fe₃O₄). Here, we demonstrate the bio-inspired synthesis of extended, self-supporting, nanometer-thin sheets of iron oxide at the water–air interface through self-assembly using small histidine-rich peptides.

The fabrication of inorganic nanomaterials is important for a wide range of disciplines.

Since the discovery of magnetotactic bacteria, researchers have been fascinated by the ability of these specialized organisms to orient within the Earth''s magnetic field.¹ To be able to react to magnetic fields, magnetotactic bacteria use specialized compartments, called magnetosomes, to produce the iron oxide magnetite (Fe₃O₄). Magnetosomes have a typical size of 30–120 nm and establish a permanent magnetic moment along a fixed axis within the bacteria.^2,3 The magnetization is used to navigate and orient within the terrestrial magnetic field to find favorable living conditions.⁴ It has been shown that the size and morphology of magnetic particles used are tightly genetically controlled and vary for different species.^5,6 The biomimetic synthesis of magnetic nanomaterials has been of substantial interest in the past years. Potential applications include biotechnology,⁷ medicine⁸ and data storage.⁹ While the biomimetic preparation of magnetic particles and surface patterns using proteins derived from magnetotactic bacteria has been reported before,^10–12 the biomimetic production of extended 2D magnetic materials using proteins has not been shown. At the same time, 2D nanomaterials have received much attention as ultrathin, high fidelity materials with new properties.¹³ Such 2D structures hold great promise as a material that can be self-assembled using effective, low-cost, bottom-up fabrication methods and then tuned chemically to the application.¹⁴ 2D materials can often be synthesized from simple building blocks and are very flexible in terms of surface morphology, porosity, chemical functionality, electronic and magnetic properties. It has been shown that functional 2D inorganic materials can be templated by organic precursor structures at interfaces.¹⁵ In nature, proteins act as the surface “engineers” and steer the growth of minerals at interfaces.¹⁶ 2D materials based on silica, calcium carbonate, and calcium oxalate have been assembled previously by biomimetic peptides at interfaces.^17–19 In this study, we describe the preparation of magnetic 2D materials using peptides mimicking the precipitation of magnetite within magnetosomes.The processes leading to the production of magnetite is complex and not entirely understood. Faivre et al. have suggested the involvement of bi- and trivalent iron ions taken up from sediments and that magnetite is then synthesized via templated ferrihydrite precursors.³ Proton pumps maintain the basic pH required for magnetite formation within the magnetosomes. In analogy to biomineralization of bone, teeth, and shells, the crystal phase and structure of the iron oxide generated have been hypothesized to be controlled by specialized proteins within the magnetosome.^10,12 Sone et al. have shown that, within these proteins, histidine sites play an important role because of their ability to chelate Fe²⁺-ions.⁶The rationale of this study has been to mimic the precipitation mechanism used by bacteria with a peptide that can precipitate iron oxide 2D sheets and also can effectively bind the air–water interface. We chose a synthetic peptide with the amino acid sequence Ac-LHHLLHLLHHLLHL (short: LHα14, see Fig. 1A), which contains only histidine (H) and leucine (L). In analogy with leucine–lysine (LK) peptides designed by deGrado and Lear,²⁰ the leucine side chains are intended to bind to the air–water interface, while histidines are expected to be exposed to the water phase and available for interactions with iron ions. The hydrophobic periodicity of 3.5 should favor an α-helical secondary structure at an interface and provide a stable platform for interfacial assembly.²¹ The peptide design allows a maximum number of histidines to be exposed to the solution phase, while the leucine are intended to stabilize the peptide at the water surface.Open in a separate windowFig. 1(A) Front and side view of the LHα14 peptide after energy minimization in bulk water using the software package PEP-FOLD. The sequence is designed to induce a helical fold with hydrophobic leucines for binding to the air–water interface on one side and iron-chelating histidines on the other sides. (B) Schematic of the film formation process. (C) SFG spectra collected with ssp and sps polarization for LHα14 at the solution-air interface before and after the iron precipitation is triggered by increasing the solution pH.We used SFG spectroscopy and surface tension measurements to follow the surface assembly (schematic in Fig. 1B and S1^†): first, LHα14 is injected into a Teflon trough with the iron chloride solution at neutral pH. The surface tension increased to 19.1 ± 0.8 mN m⁻¹ (measured of 3000 s after stabilization of the film assembly) upon peptide injection, indicating full monolayer coverage of the water surface. The structure of the LHα14 monolayer was determined using sum-frequency generation (SFG) spectroscopy in the amide I region.²² SFG can probe the secondary structure and orientation of peptides and proteins at liquid surfaces. As second-order nonlinear spectroscopy, SFG is intrinsically surface-specific due to selection rules: SFG is only allowed where inversion symmetry is broken, which is typically the case within an interfacial layer between two bulk isotropic media, such as water and air.²³ Amide I SFG spectra of LHα14 at the FeCl solution surface collected with ssp (s-polarized SFG, s-polarized visible, p-polarized infrared) and sps polarization, are shown in Fig. 1C. Both ssp and sps SFG spectra show a pronounced amide I band centered near 1644 cm⁻¹, which can be assigned to α-helical structure in D₂O.²⁴Following surface adsorption, the subphase was diluted by a factor of eight to reduce the bulk peptide concentration and avoid precipitation in the volume. Subsequently, the pH is increased using ammonia vapor to trigger the precipitation of iron oxide by protonating the histidine sites. SFG spectra recorded in this state (Fig. 1C) show a reduction of the signal level but the resonance position remains unchanged at basic pH. This implies that the secondary structure of LHα14 remains unchanged.The interaction of protonated LHα14 with iron ions leads to the precipitation of sheets of iron oxide which can be lifted off the solution surface with transmission electron microscopy (TEM) grids (Fig. 2A). A TEM image of a film transferred from the air–water is shown in Fig. 2A. The sheet covers the openings within the TEM grid and is stable on a length scale of tens of micrometers. Control samples, where iron oxide was precipitated without LHα14, resulted in fragmented and unstable films, as can be seen in the SEM image of a film deposited onto a silicon wafer surface in Fig. 2B. Clearly, the peptides are key to stabilize the iron oxide layer. Higher-resolution SEM images in Fig. 2C and D show the LHα14-precipitated films have a sponge-like porous structure consisting of ∼15 nm particles interconnected by wire-like protrusions. Atomic force microscopy (AFM) showed the particles are approximately 20 nm high, leading to the conclusion the particles are roughly spherical (see Fig. 3). The films have a thickness of 22.2 ± 4.3 nm according to AFM line scans across edges of the film.Open in a separate windowFig. 2(A) TEM image of LHα14-templated iron oxide nanosheets spanning the holes of a TEM grid. (B) SEM image of iron oxide film precipitated without peptides and deposited onto a silicon wafer. (C and D) SEM images of LHα14-precipated sheets. (E) TEM image of freestanding nanosheets. The higher resolution TEM in (F) shows crystalline domains. (G) Electron diffraction pattern of the nanosheets.Open in a separate windowFig. 3Atomic force microscopy image of LHα14 precipitated iron oxide nanosheets. (Left) Nanosheet at the edge of a defect to measure the height profile going from the substrate to the iron oxide sheet. The height difference is 22.2 ± 4.3 nm. (Right) Higher magnification image at the position marked in the left panel. The height profile shows an average particle height of 20 nm.High-resolution TEM images of an edge in the film are displayed in Fig. 2E. It can be clearly seen that the films are freestanding nanosheets and stable without substrate support. The sheets consist of amorphous areas without crystalline structure and crystalline domains of an approximate size of the particles (Fig. 2F). The respective electron diffraction pattern (Fig. 2G) shows the diffraction rings related to the polycrystalline structures. The average intensities as a function of the diffraction angle are plotted along with reference peak positions for ferrihydrite (red) and magnetite (cyan).²⁵ The ferrihydrite diffraction peaks are generally in good agreement with the experimental peak positions. Some diffraction peaks are not fully resolved within the resolution of the experiment and appear as shoulders (e.g. the peak near 27 nm⁻¹). This is likely also the reason the first two ferrihydrite peaks are not visible in the experimental data. Several peak positions and their relative intensities match the typical magnetite diffraction peaks near 24, 37, 39 and 42 nm⁻¹. The data show that the nanosheets contain both magnetite and its precursor ferrihydrite.X-ray photoelectron spectroscopy (XPS) shows that the sheets contain significant amounts of iron and oxygen as well as the expected nitrogen and carbon from the peptides in the film (

Release patterns of pregnancy‐associated plasma protein A in patients with acute coronary syndromes assessed by an optimized monoclonal antibody assay

Objective. Pregnancy‐associated plasma protein A (PAPP‐A) is expressed in eroded and ruptured atheromatous plaques, and circulating levels are elevated in acute coronary syndromes (ACS). Our objective was to investigate release patterns of PAPP‐A in ACS and whether they differ among different types of ACS. Methods. In 40 patients, PAPP‐A concentrations were measured in serially collected samples assessed by a novel ELISA technique. The patients were grouped according to type of ACS. Results. Release patterns for ST elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention (pPCI) showed a single substantial PAPP‐A increase shortly after pPCI, followed by an abrupt return to normal levels without secondary peaks. STEMI, high‐risk and low‐risk non‐ST elevation myocardial infarction/unstable angina pectoris (NSTEMI/UAP) patients without pPCI showed highly variable patterns with primary peaks followed by secondary PAPP‐A increases. All patients with elevated PAPP‐A levels reached the upper reference level within 24?h. There was a significant difference in median peak levels between STEMI (23.2?mIU/L) and low‐risk ACS patients (6.35?mIU/L) (p = 0.004) and between high‐risk (median = 15.3?mIU/L) and low‐risk ACS patients (p = 0.01). Among high‐risk ACS patients, NSTEMI patients had significantly higher peak levels than UAP patients (p = 0.003). Conclusion. PAPP‐A serum levels increase above normal values within 24?h after onset of symptoms in ACS. There are significant differences in PAPP‐A peak levels and release patterns across the spectrum of ACS patients.     

Increase in signal-to-noise ratio of > 10,000 times in liquid-state NMR

A method for obtaining strongly polarized nuclear spins in solution has been developed. The method uses low temperature, high magnetic field, and dynamic nuclear polarization (DNP) to strongly polarize nuclear spins in the solid state. The solid sample is subsequently dissolved rapidly in a suitable solvent to create a solution of molecules with hyperpolarized nuclear spins. The polarization is performed in a DNP polarizer, consisting of a super-conducting magnet (3.35 T) and a liquid-helium cooled sample space. The sample is irradiated with microwaves at approximately 94 GHz. Subsequent to polarization, the sample is dissolved by an injection system inside the DNP magnet. The dissolution process effectively preserves the nuclear polarization. The resulting hyperpolarized liquid sample can be transferred to a high-resolution NMR spectrometer, where an enhanced NMR signal can be acquired, or it may be used as an agent for in vivo imaging or spectroscopy. In this article we describe the use of the method on aqueous solutions of [13C]urea. Polarizations of 37% for 13C and 7.8% for 15N, respectively, were obtained after the dissolution. These polarizations correspond to an enhancement of 44,400 for 13C and 23,500 for 15N, respectively, compared with thermal equilibrium at 9.4 T and room temperature. The method can be used generally for signal enhancement and reduction of measurement time in liquid-state NMR and opens up for a variety of in vitro and in vivo applications of DNP-enhanced NMR.     

Eradication of glioblastoma,and breast and colon carcinoma xenografts by Hsp70 depletion

Heat shock protein 70 (Hsp70) is an antiapoptotic chaperone protein highly expressed in human tumors. Here we demonstrate that locoregional application of adenovirus expressing antisense Hsp70 cDNA (Ad.asHsp70) eradicates orthotopic xenografts of glioblastoma and breast carcinoma, as well as s.c. xenografts of colon carcinoma in immunodeficient mice. Ad.asHsp70-treated tumors showed massive apoptosis-like cell death and recruitment of macrophages. Human monocyte-derived macrophages effectively removed the corpses of Ad.asHsp70-treated tumor cells in vitro. Interestingly, both tumor cell death and phagocytosis were caspase-independent. Thus, Hsp70 appears as a promising target for the treatment of cancers resistant to classic caspase-mediated apoptosis.