OBJECTIVE Craniopharyngioma (CP) adherence strongly influences the potential for achieving a radical and safe surgical treatment. However, this factor remains poorly addressed in the scientific ...literature. This study provides a rational, comprehensive description of CP adherence that can be used for the prediction of surgical risks associated with the removal of these challenging lesions. METHODS This study retrospectively analyzes the evidence provided in pathological, neuroradiological, and surgical CP reports concerning 3 components of the CP attachment: 1) the intracranial structures attached to the tumor; 2) the morphology of the adhesion; and 3) the adhesion strength. From a total of 1781 CP reports published between 1857 and 2016, a collection of 500 CPs providing the best information about the type of CP attachment were investigated. This cohort includes autopsy studies (n = 254); surgical studies with a detailed description or pictorial evidence of CP adherence (n = 298); and surgical CP videos (n = 61) showing the technical steps for releasing the attachment. A predictive model of CP adherence in hierarchical severity levels correlated with surgical outcomes was generated by multivariate analysis. RESULTS The anatomical location of the CP attachment occurred predominantly at the third ventricle floor (TVF) (54%, n = 268), third ventricle walls (23%, n = 114), and pituitary stalk (19%, n = 94). The optic chiasm was involved in 56% (n = 281). Six morphological patterns of CP attachment were identified: 1) fibrovascular pedicle (5.4%); 2) sessile or patch-like (21%); 3) cap-like (over the CP top, 14%); 4) bowl-like (around the CP bottom, 13.5%); 5) ring-like (encircling central band, 19%); and 6) circumferential (enveloping the entire CP, 27%). Adhesion strength was classified in 4 grades: 1) loose (easily dissectible, 8%); 2) tight (requires sharp dissection, 32%); 3) fusion (no clear cleavage plane, 40%); and 4) replacement (loss of brain tissue integrity, 20%). The types of CP attachment associated with the worst surgical outcomes are the ring-like, bowl-like, and circumferential ones with fusion to the TVF or replacement of this structure (p < 0.001). The CP topography is the variable that best predicts the type of CP attachment (p < 0.001). Ring-like and circumferential attachments were observed for CPs invading the TVF (secondary intraventricular CPs) and CPs developing within the TVF itself (infundibulo-tuberal CPs). Brain invasion and peritumoral gliosis occurred predominantly in the ring-like and circumferential adherence patterns (p < 0.001). A multivariate model including the variables CP topography, tumor consistency, and the presence of hydrocephalus, infundibulo-tuberal syndrome, and/or hypothalamic dysfunction accurately predicts the severity of CP attachment in 87% of cases. CONCLUSIONS A comprehensive descriptive model of CP adherence in 5 hierarchical levels of increased severity-mild, moderate, serious, severe, and critical-was generated. This model, based on the location, morphology, and strength of the attachment can be used to anticipate the surgical risk of hypothalamic injury and to plan the degree of removal accordingly.
Six new secocycloartane glycosides (1–6) were isolated from the ethanol extract of the flowers of Cordia lutea Lam. on the basis of bioassay-guided fractionation. Their structures were determined by ...the application of NMR and MS data analyses together with X-ray crystallographic analyses for compounds 1 and 2. Compounds 1–6 represent the first examples of 9,10-seco-29-norcycloartane glycosides. These compounds showed significant in vitro anti-Helicobacter pylori activity, and no activity against either Escherichia coli or Pseudomonas aeruginosa. Significant activity was observed for 5 and 6 against Staphylococcus aureus. All compounds displayed weak cytotoxicity against RAW 264.7 cells. The in vitro antileishmanial and antiplasmodial activities of 1–6 were also evaluated.
ABSTRACT
Protoplanetary discs are complex dynamical systems where several processes may lead to the formation of ring-like structures and planets. These discs are flared following a profile where the ...vertical scale height increases with radius. In this work, we investigate the role of this disc flaring geometry on the formation of rings and holes. We combine a flattening law change with X-ray and FUV photoevaporative winds. We have used a semi-analytical 1D viscous α approach, presenting the evolution of the disc mass and mass rate in a grid of representative systems. Our results show that changing the profile of the flared disc may favour the formation of ring-like features resembling those observed in real systems at the proper evolutionary times, with proper disc masses and accretion rate values. However, these features seem to be short-lived and further enhancements are still needed for better matching all the features seen in real systems.
High reddening patches in Gaia DR2 Beitia-Antero, Leire; Gómez de Castro, Ana Inés; de la Fuente Marcos, Raúl
Astronomy and astrophysics (Berlin),
02/2020, Letnik:
634
Journal Article
Recenzirano
Context.
Deep GALEX UV data show that the extreme outskirts of some spiral galaxies are teeming with star formation. Such young stellar populations evolving so far away from the bulk of their host ...galaxies challenge our overall understanding of how star formation proceeds at galactic scales. It is at present unclear whether our own Milky Way may also exhibit ongoing and recent star formation beyond the conventional edge of the disk (∼15 kpc).
Aims.
Using
Gaia
DR2 data, we aim to determine if such a population is present in the Galactic halo, beyond the nominal radius of the Milky Way disk.
Methods.
We studied the kinematics of
Gaia
DR2 sources with parallax values between 1/60 and 1/30 milliarcseconds towards two regions that show abnormally high values of extinction and reddening; the results are compared with predictions from GALAXIA Galactic model. We also plotted the color–magnitude (CM) diagrams with heliocentric distances computed inverting the parallaxes, and studied the effects of the large parallax errors by Monte Carlo sampling.
Results.
The kinematics point towards a Galactic origin for one of the regions, while the provenance of the stars in the other is not clear. A spectroscopic analysis of some of the sources in the first region confirms that they are located in the halo. The CM diagram of the sources suggests that some of them are young.
The atmospheric structure of T Tauri stars (TTSs) and its connection with the large-scale outflow is poorly known. Neither the effect of the magnetically mediated interaction between the star and the ...disc is well understood. The Mg ii multiplet is a fundamental tracer of TTSs atmospheres and outflows, and is the strongest feature in the near-ultraviolet spectrum of TTSs. The International Ultraviolet Explorer and Hubble Space Telescope data archives provide a unique set to study the main physical compounds contributing to the line profile and to derive the properties of the line formation region. The Mg ii profiles of 44 TTSs with resolution 13 000–30 000 are available in these archives. In this work, we use this data set to measure the main observables: flux, broadening, asymmetry, terminal velocity of the outflow, and the velocity of the discrete absorption components. For some few sources repeated observations are available and variability has been studied. There is a warm wind that at sub-au scales absorbs the blue wing of the Mg ii profiles. The main result found in this work is the correlation between the line broadening, Mg ii flux, terminal velocity of the flow and accretion rate. Both outflow and magnetospheric plasma contribute to the Mg ii flux. The flux–flux correlation between Mg ii and C iv or He ii is confirmed; however, no correlation is found between the Mg ii flux and the UV continuum or the H2 emission.
We present here the isolation and structural characterization of two undescribed mono-glycosylated triterpenes with a 19-hydroxy-29-norlanostane core. These compounds (1-2) were isolated from an ...ethanolic extract of the dried flowers of Cordia lutea, a widely used Peruvian traditional medicine. Their structures were determined by examination of their NMR and MS data. For compound 1, its structure was confirmed by single crystal X-ray structural analyses. 1 showed moderate activity against Helicobacter pylori (MIC = 15.6 µg/mL), and was not active against Escherichia coli, Pseudomonas aeruginosa or Staphylococcus aureus (MIC > 125 µg/mL).
Display omitted
•Cordia lutea is a widely used as a medicinal plant in Peru.•Little is known about its chemical composition.•Two new 19-hydroxy-29-norlanostane triterpenes were isolated from this herbal remedy.•One compound displayed moderate activity against Helicobacter pylori, supporting the traditional use of this plant.
Chromatin is important for the regulation of transcription and other functions, yet the diversity of chromatin composition and the distribution along chromosomes are still poorly characterized. By ...integrative analysis of genome-wide binding maps of 53 broadly selected chromatin components in Drosophila cells, we show that the genome is segmented into five principal chromatin types that are defined by unique yet overlapping combinations of proteins and form domains that can extend over > 100 kb. We identify a repressive chromatin type that covers about half of the genome and lacks classic heterochromatin markers. Furthermore, transcriptionally active euchromatin consists of two types that differ in molecular organization and H3K36 methylation and regulate distinct classes of genes. Finally, we provide evidence that the different chromatin types help to target DNA-binding factors to specific genomic regions. These results provide a global view of chromatin diversity and domain organization in a metazoan cell.
Display omitted
► Unique combinations of proteins define five principal chromatin types in Drosophila ► Two chromatin types are known types of heterochromatin ► A previously unknown type of repressive chromatin covers ∼50% of the genome ► Two distinct types of euchromatin regulate different classes of genes
The C ii feature at ∼2325 Å is very prominent in the spectra of T Tauri stars (TTSs). This feature is a quintuplet of semiforbidden transitions excited at electron temperatures around 10 000 K that, ...together with the nearby Si ii and Fe ii features, provides a reliable optically thin tracer for accurate measurement of the plasma properties in the magnetospheres of TTSs. The spectra of 20 (out of 27) TTSs observed with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope have good enough signal-to-noise ratio at the C ii wavelength. For these stars, we have determined electron densities (n
e) and temperatures (T
e) in the line emission region as well as the profile broadening (σ). For most of the stars in the sample (17), we obtain 104.1 ≲ T
e ≲ 104.5 K and 108 ≲ n
e ≲ 1012 cm−3. These stars have suprathermal line broadening (35 ≲ σ ≲ 165 km s−1), except TW Hya and CY Tau with thermal line broadening. Both C ii line luminosity and broadening are found to correlate with the accretion rate. Line emission seems to be produced in the magnetospheric accretion flow, close to the disc. There are three exceptions: DG Tau, RY Tau and FU Ori. The line centroids are blueshifted indicating that the line emission in these three stars is dominated by the outflow.
Purpose
Infundibulo-tuberal syndrome groups endocrine, metabolic and behavioral disturbances caused by lesions involving the upper neurohypophysis (median eminence) and adjacent basal hypothalamus ...(tuber cinereum). It was originally described by Henri Claude and Jean Lhermitte in 1917, in a patient with a craniopharyngioma. This study investigates the clinical, pathological and surgical evidence verifying the infundibulo-tuberal syndrome caused by craniopharyngiomas (CPs).
Methods
A systematic retrospective review of craniopharyngiomas reported in French literature between 1705 and 1973 was conducted. A total of 128 well described reports providing a comprehensive clinical and pathological description of the tumors were selected. This series represents the historical French cohort of CPs reported in the pre-CT/MRI era.
Results
Three major syndromes caused by CPs were categorized: pituitary syndrome (35 %), infundibulo-tuberal syndrome (52 %) and hypothalamic syndrome (49 %). CP topography was significantly related to the type of syndrome described (
p
< 0.001). Infundibulo-tuberal syndrome occurred in CPs which replaced or invaded the third ventricle floor. In contrast, the majority of sellar/suprasellar CPs growing below the third ventricle showed a pituitary syndrome (82 %). Cases with hypothalamic syndrome were characterized by anatomical integrity of the pituitary gland and stalk (
p
= 0.033) and occurred predominantly in adults older than 41 years old (
p
< 0.005). Among infundibulo-tuberal symptoms, abnormal somnolence was not related with the presence of hydrocephalus. All squamous-papillary CPs presented psychiatric disturbances (
p
< 0.001).
Conclusion
This historical CP cohort evidences a clinical-topographical correlation between the patient’s type of syndrome and the anatomical structures involved by the tumor along the hypophysial-hypothalamic axis.
PDF
