Morphometric analysis of muscularis proper and myenteric plexus of the normal human oesophagus. Age related changes

Background: Oesophagus is a muscular tube that transports food and liquidsby coordinated contraction of its muscular lining led by stimuli from the nerveplexus. Its muscularis proper layer consists of muscle cells, connective tissue andmyenteric plexus. The aim of our histomorphometric study was to reveal detailedcharacteristics of this layer, cell number, volume, orientation, properties of myentericplexus as well as changes related to aging.Materials and methods: Oesophagus tissue samples from 17 male cadavers weretaken from the cranial and thoracic parts. Samples were divided in 2 groups: younger(ages 21–45) and older (ages 66–78). The tissue was routinely processed,embedded and serially sectioned. Sections were stained with Masson-Goldner andCresyl-violet dyes. Digital images were analysed with the image analysis software.Statistics were performed with SPSS software.Results: The average thickness of the cranial part of the oesophageal wall andmuscularis proper was 2590 μm and 1197 μm, respectively in the younger and2453 μm and 1144 μm in the older group. Overall volume of the muscle tissuewas slightly larger in the thoracic part, and in the younger group comparedto the cranial part and the older group. The average number of the striatedmuscle cells per 100 μm in the cranial part was 771.5 and 749.7 in the youngerand the older group, respectively. Striated cells were significantly lesspresent only in the lower thoracic part of the oesophagus. In the older group,smaller striated muscle cells dominated over the larger ones. In the youngergroup, majority of the striated muscle cells were mid-sized. The thickness ofthe circular layer of muscularis proper was more affected by aging than thelongitudinal one. Ganglion cells number was lower in the older group, butplexus area was unchanged.Conclusions: Aging affects muscularis proper and myenteric plexus of the oesophagus.Major differences can be observed in the striated muscle cells size, volumeof the circular layer and number of the ganglionic cells in the myenteric plexus

Antimicrobial treatment of Corynebacterium striatum invasive infections: a systematic review

The aim of this study was to establish an evidence-based guideline for the antibiotic treatment of Corynebacterium striatum infections. Several electronic databases were systematically searched for clinical trials, observational studies or individual cases on patients of any age and gender with systemic inflammatory response syndrome, harboring C. striatum isolated from body fluids or tissues in which it is not normally present. C. striatum had to be identified as the only causative agent of the invasive infection, and its isolation from blood, body fluids or tissues had to be confirmed by one of the more advanced diagnostic methods (biochemical methods, mass spectrometry and/or gene sequencing). This systematic review included 42 studies that analyzed 85 individual cases with various invasive infections caused by C. striatum. More than one isolate of C. striatum exhibited 100% susceptibility to vancomycin, linezolid, teicoplanin, piperacillin-tazobactam, amoxicillin-clavulanate and cefuroxime. On the other hand, some strains of this bacterium showed a high degree of resistance to fluoroquinolones, to the majority majority of β-lactams, aminoglycosides, macrolides, lincosamides and cotrimoxazole. Despite the antibiotic treatment, fatal outcomes were reported in almost 20% of the patients included in this study. Gene sequencing methods should be the gold standard for the identification of C. striatum, while MALDI-TOF and the Vitek system can be used as alternative methods. Vancomycin should be used as the antibiotic of choice for the treatment of C. striatum infections, in monotherapy or in combination with piperacillin-tazobactam. Alternatively, linezolid, teicoplanin or daptomycin may be used in severe infections, while amoxicillin-clavulanate may be used to treat mild infections caused by C. striatum

Co-overexpression of bcl-2 and c-myc in uterine cervix carcinomas and premalignant lesions

To establish the role of co-overexpression of bcl-2 and c-myc protooncogenes in uterine cervix carcinogenesis, we examined 138 tissue samples of low grade cervical squamous intraepithelial lesions (SIL), high grade SIL, portio vaginalis uteri (PVU) carcinoma in situ and PVU invasive carcinoma, stage IA-IIA (study group) and 36 samples without SIL or malignancy (control group). The expression of bcl-2 and c-myc was detected immunohistochemically using a monoclonal antibody. Fisher's exact test (P<0.05) was used to assess statistical significance. Overexpression of bcl-2 was found to increase in direct relation to the grade of the cervical lesions. High sensitivity was of great diagnostic significance for the detection of these types of changes in the uterine cervix. On the basis of high predictive values it can be said that in patients with bcl-2 overexpression there is a great possibility that they have premalignant or malignant changes in the uterine cervix. Co-overexpression of bcl-2 and c-myc oncogenes was found only in patients with PVU invasive carcinoma (6/26-23.0%). Statistically significant difference was not found in the frequency of co-overexpression in patients with PVU invasive carcinoma in relation to the control group (Fisher's test; P=0.064). The method's sensitivity of determining these oncogenes with the aim of detecting PVU invasive carcinoma was 23%, while specificity was 72.2%. On the basis of high predictive values (100%), speaking in statistical terms, it can be concluded that all patients with co-overexpression of bcl-2 and c-myc oncogenes will have PVU invasive carcinoma. We confirmed in our research that co-overexpression of bcl-2 and c-myc oncogenes was increased only in PVU invasive carcinoma. However, a more extensive series of samples and additional tests are required to establish the prognostic significance of bcl-2 and c-myc co-overexpression in cervical carcinogenesis

Novel Electron Spectroscopy of Tenuously and Weakly Bound Negative Ions

A novel method is proposed that uses very slow electron elastic collisions with atoms to identify their presence through the observation of tenuously bound (electron impact energy, E<0.1 eV) and weakly bound (E<1 eV) negative ions, formed as Regge resonances during the collisions.Comment: 4pages, 3figure

Direct Formation of Supermassive Black Holes via Multi-Scale Gas Inflows in Galaxy Mergers

Observations of distant bright quasars suggest that billion solar mass supermassive black holes (SMBHs) were already in place less than a billion years after the Big Bang. Models in which light black hole seeds form by the collapse of primordial metal-free stars cannot explain their rapid appearance due to inefficient gas accretion. Alternatively, these black holes may form by direct collapse of gas at the center of protogalaxies. However, this requires metal-free gas that does not cool efficiently and thus is not turned into stars, in contrast with the rapid metal enrichment of protogalaxies. Here we use a numerical simulation to show that mergers between massive protogalaxies naturally produce the required central gas accumulation with no need to suppress star formation. Merger-driven gas inflows produce an unstable, massive nuclear gas disk. Within the disk a second gas inflow accumulates more than 100 million solar masses of gas in a sub-parsec scale cloud in one hundred thousand years. The cloud undergoes gravitational collapse, which eventually leads to the formation of a massive black hole. The black hole can grow to a billion solar masses in less than a billion years by accreting gas from the surrounding disk.Comment: 26 pages, 4 Figures, submitted to Nature (includes Supplementary Information

Sexual dimorphism of medium-sized neurons with spines in human nucleus accumbens

The nucleus accumbens is a limbic nucleus, representing part of the striatum body, and together with the caudate nucleus and putamen, it lies on the septum. The aim of this study was to examine morphological sexual dimorphism in spine density and also to undertake an immunohistochemical study of expression for estrogen and progesterone receptors in the medium-sized neurons in the nucleus accumbens. The research was conducted on twenty human brains of persons of both sexes, between the age of 20-75 years. The Golgi method was applied to determine the types and subtypes of neurons, morphologies of soma, dendrites and axons, as well as the relations between the cells and glial elements. The following were quantitatively examined: the maximum diameter of the neurons, the minimal diameter of the neurons, and the total length of the dendrites. The expression of receptors for estrogen and progesterone, their distribution and intensity were defined immunohistochemically. The parameters of the bodies of neurons in the shell and core of the nucleus accumbens were studied in both men and women. No statistically significant differences were found. Examination of the spine density showed statistical significance in terms of a higher density of spines in women. Immunohistochemically, in the female brain estrogen expression is diffusely spread in a large number of neurons; it is extra nuclear, of granular appearance and high intensity. In the male brain, expression of estrogen is visible and distributed over about one half of different types of neurons; it is extra nuclear, of granular appearance, mostly of middle and low staining intensity. Expression of progesterone in the female brain was very discreet and on a very small number of neurons; it was extra nuclear and with a weak staining intensity. Expression of progesterone in the male brain was distributed on a small number of neurons. It had a granular appearance, it was extra nuclear, with a very low staining intensity. Our results show differences in the morphology as well as expression of receptors for estrogen and progesterone on medium-sized neurons with spines in the nucleus accumbens of men and women

The Formation and Evolution of the First Massive Black Holes

The first massive astrophysical black holes likely formed at high redshifts (z>10) at the centers of low mass (~10^6 Msun) dark matter concentrations. These black holes grow by mergers and gas accretion, evolve into the population of bright quasars observed at lower redshifts, and eventually leave the supermassive black hole remnants that are ubiquitous at the centers of galaxies in the nearby universe. The astrophysical processes responsible for the formation of the earliest seed black holes are poorly understood. The purpose of this review is threefold: (1) to describe theoretical expectations for the formation and growth of the earliest black holes within the general paradigm of hierarchical cold dark matter cosmologies, (2) to summarize several relevant recent observations that have implications for the formation of the earliest black holes, and (3) to look into the future and assess the power of forthcoming observations to probe the physics of the first active galactic nuclei.Comment: 39 pages, review for "Supermassive Black Holes in the Distant Universe", Ed. A. J. Barger, Kluwer Academic Publisher

Evolution of supermassive black holes

Supermassive black holes (SMBHs) are nowadays believed to reside in most local galaxies, and the available data show an empirical correlation between bulge luminosity - or stellar velocity dispersion - and black hole mass, suggesting a single mechanism for assembling black holes and forming spheroids in galaxy halos. The evidence is therefore in favour of a co-evolution between galaxies, black holes and quasars. In cold dark matter cosmogonies, small-mass subgalactic systems form first to merge later into larger and larger structures. In this paradigm galaxy halos experience multiple mergers during their lifetime. If every galaxy with a bulge hosts a SMBH in its center, and a local galaxy has been made up by multiple mergers, then a black hole binary is a natural evolutionary stage. The evolution of the supermassive black hole population clearly has to be investigated taking into account both the cosmological framework and the dynamical evolution of SMBHs and their hosts. The seeds of SMBHs have to be looked for in the early Universe, as very luminous quasars are detected up to redshift higher than z=6. These black holes evolve then in a hierarchical fashion, following the merger hierarchy of their host halos. Accretion of gas, traced by quasar activity, plays a fundamental role in determining the two parameters defining a black hole: mass and spin. A particularly intriguing epoch is the initial phase of SMBH growth. It is very challenging to meet the observational constraints at z=6 if BHs are not fed at very high rates in their infancy.Comment: Extended version of the invited paper to appear in the Proceedings of the Conference "Relativistic Astrophysics and Cosmology - Einstein's Legacy

Identifying Decaying Supermassive Black Hole Binaries from their Variable Electromagnetic Emission

Supermassive black hole binaries (SMBHBs) with masses in the range 10^4-10^7 M_sun/(1+z), produced in galaxy mergers, are thought to complete their coalescence due to the emission of gravitational waves (GWs). The anticipated detection of the GWs by the LISA will constitute a milestone for fundamental physics and astrophysics. While the GW signatures themselves will provide a treasure trove of information, if the source can be securely identified in electromagnetic (EM) bands, this would open up entirely new scientific opportunities, to probe fundamental physics, astrophysics, and cosmology. We discuss several ideas, involving wide-field telescopes, that may be useful in locating electromagnetic counterparts to SMBHBs detected by LISA. In particular, the binary may produce a variable electromagnetic flux, such as a roughly periodic signal due to the orbital motion prior to coalescence, or a prompt transient signal caused by shocks in the circumbinary disk when the SMBHB recoils and "shakes" the disk. We discuss whether these time-variable EM signatures may be detectable, and how they can help in identifying a unique counterpart within the localization errors provided by LISA. We also discuss a possibility of identifying a population of coalescing SMBHBs statistically, in a deep optical survey for periodically variable sources, before LISA detects the GWs directly. The discovery of such sources would confirm that gas is present in the vicinity and is being perturbed by the SMBHB - serving as a proof of concept for eventually finding actual LISA counterparts.Comment: 10 pages with 4 figures; submitted to Classical and Quantum Gravity (special issue for the proceedings of the 7th International LISA Symposium