[Multiple cerebral haemorrhages secondary to disseminated intravascular coagulation in a patient with COVID-19]. / Hemorragias cerebrales múltiples secundarias a coagulación intravascular diseminada en un paciente con COVID-19.

TITLE: Hemorragias cerebrales múltiples secundarias a coagulación intravascular diseminada en un paciente con COVID-19.

Tuning the Size of Palladium Nanoparticles in Organic and Aqueous Solutions: Influence of Aminated and Thiolated Ligands.

Highly monodispersed palladium nanoparticles have been synthesized by a two-phase reduction method using two different capping agents, alkylamines and alkanethiols. The influence of ligand type in the properties of palladium nanoparticles have been analyzed in detail by means of several techniques as Infrared and Ultraviolet-Visible Spectroscopy, X-ray Diffraction and Transmission Electron Microscopy. It is shown how the size can be tuned easily between 2 and 4 nm by using alkylamines ligands with carbon chains of different lengths, while keeping up high purity and crystallinity. The transfer of these nanoparticles to water phase has been achieved by the ligand exchange process. In contrast, when alkanethiols are used as stabilizers no correlation between carbon chain length and size has been observed. This distinct chemical reactivity between palladium and mentioned ligands produces some particular electronic and magnetic properties that are analyzed by Electron Magnetic Resonance. The presence of free radicals associated with palladium and capping agent bond has been confirmed. No evidences of ferromagnetic behavior coming from Palladium nanoparticles have been found out in any of the studied samples.

Effect of Carbon Coating on the Physicochemical and Electrochemical Properties of Fe2O3 Nanoparticles for Anode Application in High Performance Lithium Ion Batteries.

Nanoparticulate Fe2O3 and Fe2O3/C composites with different carbon proportions have been prepared for anode application in lithium ion batteries (LIBs). Morphological studies revealed that particles of Fe2O3 in the composites were well-dispersed in the matrix of amorphous carbon. The properties of the γ-Fe2O3 nanoparticles and the correlation with the particle size and connectivity were studied by electron paramagnetic resonance, magnetic, and Mössbauer measurements. The electrochemical study revealed that composites with carbon have promising electrochemical performances. These samples yielded specific discharge capacities of 1200 mAh/g after operating for 100 cycles at 1C. These excellent results could be explained by the homogeneity of particle size and structure as well as the uniform distribution of γ-Fe2O3 nanoparticles in the in situ generated amorphous carbon matrix.

Age, sex and personality in early cannabis use.

Previous studies analysing personality and cannabis use in adult samples suggest that cannabis users show significant higher levels of impulsivity, sensation seeking and schizotypy. However, there are few studies exploring this relationship in adolescence using psychobiological models of personality. Given the relevance of identifying individual differences that lead adolescents to early cannabis use to prevent future health problems, the present study aimed to explore the relationship between age, sex, personality and early cannabis use using a psychobiological model of personality in a sample of 415 students (51.8% boys) from 12 to 18 years. Chi(2) tests showed significant higher prevalence of cannabis use in boys and in the group aged 15-18 years. Multiple analysis of variance showed significant higher scores in psychoticism, sensation seeking and in all its subscales in cannabis users group, while an interaction with age was found for extraversion and neuroticism: cannabis users scored higher than non-users in the youngest group (12-14 years) but lower in the oldest group in both dimensions. Finally, regression analysis showed that narrower traits of sensation seeking (experience seeking and disinhibition) were the most associated to early cannabis use. Results are discussed in terms of early cannabis users' personality profiles and in terms of the self-medication theory.

Specific absorption rate of magnetite nanoparticle powders with and without surrounding organic ligands.

Magnetite nanoparticles have been synthesized at different temperatures in order to get nanoparticles of different average sizes. Powders of the synthesized nanoparticles were introduced in a radio frequency electromagnetic apparatus built to perform hyperthermia measurements in laboratory animals. The nanoparticles synthesized at 80 degrees C, the ones giving the largest specific absorption rate values, have been functionalized with different organic ligands to study the influence of functionalization on specific absorption rate values. In all the synthesized nanoparticles, with and without organic surroundings, specific absorption rate measurements have been performed to study the influence of applied magnetic field intensity an frequency.

Functionalized Fe3O4@Au superparamagnetic nanoparticles: in vitro bioactivity.

The interaction of nanoparticles with cells has been a focus of interest during the past decade. We report the fabrication and characterization of hydrosoluble Fe3O4@Au nanoparticles functionalized with biocompatible and fluorescent molecules and their interaction with cell cultures by visualizing them with confocal microscopy. Gold covered iron oxide nanoparticles were synthesized by reducing metal salts in the presence of oleylamine and oleic acid. The functionalization of these particles with an amphiphilic polymer provides a water soluble corona as well as the possibility to incorporate different molecules relevant for bio-applications such as poly(ethylene glycol), glucose or a cadaverine derived dye. The particle size, and the presence of polymer layers and conjugated molecules were characterized and confirmed by transmission electron microscopy, thermogravimetric measurements and infrared spectroscopy. A complete magnetic study was performed, showing that gold provides an optimum coating, which enhances the superparamagnetic behaviour observed above 10-15 K in this kind of nanoparticle. The interaction with cells and the cytotoxicity of the Fe3O4@Au preparations were determined upon incubation with the HeLa cell line. These nanoparticles showed no cytotoxicity when evaluated by the MTT assay and it was demonstrated that nanoparticles clearly interacted with the cells, showing a higher level of accumulation in the cells for glucose conjugated nanoparticles.

Magnetic resonance venography of the lower limb.

Prior to surgery or endovascular therapy for the lower extremity varicose veins or deep venous thrombosis (DVT), ultrasonography provides useful information. But it depends on the operator's technique, each image is limited to a small field of view and interpretation may be subjective. On the other hand, magnetic resonance (MR) imaging is now available with several postprocessing techniques using workstations to demonstrate the gross and objective morphology of these lesions less invasively than the conventional ascending venography. As non-contrast MR venography, fat suppressed three-dimensional (3D) coronal balanced turbo field echo (bTFE) is mainly applied in the semisupine position. The varicose veins on the muscle fascia are easily recognized on volume rendering and the perforating veins can be identified on maximum intensity projection (MIP) and axial multiplanar reconstructions. Gadolinium-enhanced fluid attenuated inversion recovery-bTFE is added when coexisting joint effusion or edema masks the veins. For DVT, direct thrombus imaging (DTI) using fat suppressed 3D coronal inversion recovery-prepared blood suppressed gradient echo sequence is applied. However, the signal intensity of DVT depends on the clot's age on DTI and is sometimes confusing on bTFE. After gadolinium administration, blood shows higher signal intensity than clots regardless of the age and DVT can be easily depicted as filling defects on the axial reformations and summarized on the soap bubble-MIP.

Lack of involvement of mitochondrial factors in caspase activation in a Drosophila cell-free system.

Although mitochondrial proteins play well-defined roles in caspase activation in mammalian cells, the role of mitochondrial factors in caspase activation in Drosophila is unclear. Using cell-free extracts, we demonstrate that mitochondrial factors play no apparent role in Drosophila caspase activation. Cytosolic extract from apoptotic S2 cells, in which caspases were inhibited, induced caspase activation in cytosolic extract from normal S2 cells. Mitochondrial extract did not activate caspases, nor did it influence caspase activation by cytosolic extract. Silencing of Hid, Reaper, or Grim reduced caspase activation by apoptotic cell extract. Furthermore, a peptide representing the amino terminus of Hid was sufficient to activate caspases in cytosolic extract, and this activity was not enhanced by addition of mitochondria or mitochondrial lysate. The Hid peptide also induced apoptosis when introduced into S2 cells. These results suggest that caspase activation in Drosophila is regulated solely by cytoplasmic factors and does not involve any mitochondrial factors.

Novel laser system and laser irradiation method reduced the risk of carbonization during laser interstitial thermotherapy: assessed by MR temperature measurement.

BACKGROUND AND OBJECTIVE: To establish laser interstitial thermotherapy (LITT) for intracranial tumors, the authors investigated a method to regulate localized temperature generated by interstitial laser irradiation using magnetic resonance (MR) temperature mapping. STUDY DESIGN/MATERIALS AND METHODS: A diode laser system and six different types of optical-fiber system were developed for LITT. The characteristics of temperature profiles produced by each laser-fiber system were investigated with MR temperature measurement (the water proton chemical technique), and differences in the temperature profile induced by two laser-irradiation methods (continuous and intermittent) were observed. RESULTS: All fiber systems with the exception of the diffuse-projection fiber system, created a spherical temperature profile. Carbonization sometimes occurred around the bare-end fiber tip upon high power laser irradiation. The diffuse-projection fiber system produced a cylindrical temperature distribution, and the temperature profile showed a more gradual temperature elevation than the bare-end fiber. No carbonization occurred at the tip of the diffuse-projection fiber system. In addition, the utilization of the intermittent irradiation method also increased temperature gradually. Fiber-system modification and intermittent irradiation reduced laser-beam intensity and the risk of carbonization. CONCLUSION: The use of a diffuse-projection fiber system which intermittently transmits a reduced intensity laser beam is an effective tool to regulate temperature during LITT using MR temperature measurement.

Application and validation of three-dimensional data sets from a phase contrast MR angiography for preoperative computer simulation of brain tumors.

We applied a three-dimensional (3D) phase contrast magnetic resonance angiography as the source for generating integrated 3D images for surgical planning of brain tumors. In the 3D model, we defined the Cingulomarginal sulcus and subsequently the central sulcus in the interhemispheric plane. This method solved the misregistration problem caused by the combination of multi-sequence data sets and can be feasible for surgical planning.

Relation of bimanual coordination to activation in the sensorimotor cortex and supplementary motor area: analysis using functional magnetic resonance imaging.

The aim of this study was to analyze how functional activation in the supplementary motor area (SMA) and sensorimotor cortex (SMC) is related to bimanual coordination using functional magnetic resonance imaging. Subjects included 24 healthy volunteers, 15 of whom were right-handed and 9 left-handed. Three kinds of activation tasks, all of which required the repetitive closing and opening of a fist, were performed: unimanual movement of the nonpreferred hand (task A); simultaneous, agonistic movement of both hands (task B); simultaneous, antagonistic movement of both hands (task C). The SMA activation during task C was more pronounced than that during the other two tasks for right and left handers. The results suggested that the activation of the SMA, at least during a simple motion used in the present study, was little influenced by whether the motion was unimanual or bimanual but instead how the bimanual motion was composed of the motion element of a single hand. The SMC activation during task C was significantly larger than that during task B, whereas hemispheric differences in the activation were not found. This indicated that the complexity of the bimanual movement also affected the SMC activation.

Magnetic resonance cisternography for visualization of intracisternal fine structures.

OBJECT: To assess its usefulness in demonstrating cisternal anatomy, the authors investigated magnetic resonance (MR) cisternography in which a heavily T2-weighted turbo spin-echo method was used to visualize normal anatomical fine structures and lesions in the basal cisterns in 20 healthy volunteers and 43 patients. The authors applied peripheral pulse gating, which had been optimized to reduce artifacts in the cisterns attributable to cerebrospinal fluid (CSF) flow. METHODS: The detectability of each cranial nerve was determined in healthy volunteers. The first, second, and third nerves and the seventh-eighth nerve complex were clearly visualized in all participants; the fifth nerve was clearly seen in 80% and the sixth cranial nerve in 50%. The fourth nerve and the ninth through 12th nerves were difficult to identify individually, except in some volunteers. To reduce artifacts caused by fast CSF flow, we determined the delays as a function of the time elapsed between two consecutive peaks of pulse wave in a peripheral pulse gate (P-P interval) at which there was reversal of flow direction to minimize the CSF flow-related artifact. Using peripheral pulse gating and a time delay of 30% of the R-R interval, the authors succeeded in minimizing the CSF flow-related artifacts. Magnetic resonance cisternography appears to be very useful for demonstrating intracisternal fine anatomy and enhancing the contours of the juxtacisternal lesion. A minute amount of CSF interposed between lesions and normal structures such as nerves, vessels, or bone structures can be detected by means of this sequence. In patients with facial spasm, axial images and oblique coronal images obtained in a plane parallel to the seventh-eighth cranial nerve complex demonstrated vascular compression in all 13 patients. The MR cisternography finding of compression was confirmed in all nine patients who underwent microvascular decompression. CONCLUSIONS: Magnetic resonance cisternography appears to show great promise for evaluation of patients with neurovascular compression or tumors in and around the basal cisterns; the procedure adds only a small amount of imaging time.

[Urethral stenosis: optical internal urethrotomy versus termino-terminal urethroplasty]. / Estenosis de uretra: uretrotomía interna óptica versus uretroplastia término terminal.

Presentation of our statistics of 70 cases of Internal Optical Urethrotomy with a follow-up greater than twenty months. Also, review of forty-four End Terminal Urethroplasties. When compared, the best results were obtained with Urethroplasties, 90%, versus only 49% satisfactory results with cold cut Optical Urethrotomy.

[Computerized single probe system using a cadmium telluride detector].

Using cadmium telluride (CdTe) as a detector, we assembled a computerized single probe system. The size of the CdTe used is 16 mm in diameter and 2 mm in thickness. Two types of the straight bore collimators of 16 mm in diameter were prepared. One is 16 mm in length (long type) and the other is 5 mm in length (short type). The response curves of the long and short type collimators to 57Co in water showed that the points at 10% of maximum counts were 4 cm and 3 cm in depth along the center axis. The data were accumulated by using a commercialized single cardiac probe system (OMNISCOPE) and processed by itself or transferred to the microcomputer (LSI-11/23) for further analysis. Twenty percent count loss occurred at 100 000 cps with an integral discriminator setting. This system was applied for cerebrospinal fluid (CSF) shunt flow evaluation and measurement of left ventricular ejection fraction (LVEF). Measurement of CSF shunt flow has been able to do in any patient's positioning. In 21 patients with various heart diseases, LVEFs obtained by CdTe detector were compared with those obtained by scintillation detector. There was good correlation between the LVEFs obtained by these two detectors: correlation coefficient (r)=0.939.