Lemurs - Ambassadors for Madagascar

In this short article on lemurs I give a concise introduction for non-specialists to these conspicuous and unique animals on the island of Madagascar

Immunohistochemical determination of p53 overexpression: An easy and readily available method to identify progression in superficial bladder cancer?

Overexpression of p53, as determined by immunohistochemical staining with the murine monoclonal antibody DO7, was determined in specimens of 46 primary superficial transitional cell bladder tumours (14 TaG2, 10 T1G2, 22 T1G3). A colon cancer specimen served as a positive control and normal mesenchymal cells in the specimens served as an internal negative control. An exceptionally high proportion 36/46 (78%) of the specimens were found to stain positively for p53 in over 20% of the cell nuclei. After a median follow-up of 7 years, ten patients developed progressive disease. Of these ten patients nine demonstrated p53 positivity, resulting in a sensitivity of 90%. However, 27 of the overall 36 patients (75%) with p53-positive tumours did not progress to a higher stage or metastatic disease. These findings suggest that p53 overexpression is not of predictive prognostic value in superficial transitional cell carcinoma. With 7 of 14 specimens (50%) of Ta tumours overexpressing p53, the results were suggestive of p53 mutation being an early event in carcinogenesis. When the threshold was set at 50% of the cell nuclei overexpressing p53, 16/46 (35%) classified as p53 positive. Of the 16 tumours staining positively for p53, 7 (46%) progressed and 9 (56%) did not. None of the Ta and 16 (50%) of the T1 tumours classified as positive. This more stringent definition of positivity still does not identify p53 positivity as a single prognostic factor. With 50% of T1 tumours classifying as positive, we still find that p53 mutation may be an early event in carcinogenesis of bladder cance

Ultrasound-guided spermatic cord block for scrotal surgery

Background Performing spermatic cord block for scrotal surgery avoids the potential risks of neuraxial and general anaesthesia and provides long-lasting postoperative analgesia. A blindly performed block is often inefficient and bears its own potential risks (intravascular injection of local anaesthetics, haematoma formation and perforation of the deferent duct). The use of ultrasound may help to overcome these disadvantages. The aim of this study was to test the feasibility and monitor the success rate of a new ultrasound-guided spermatic cord block. Methods Twenty consecutive patients undergoing urologic surgery (subcapsular orchiectomy or vaso-vasostomy) were included in this prospective study. Using a linear ultrasound probe, the spermatic cord was identified by locating the spermatic artery and the deferent duct. A 23 G Microlance needle was advanced close to the deferent duct by avoiding vessel perforation, and local anaesthetic was deposited around the deferent duct under direct visualization. The primary outcome was the success rate of the block which was defined as surgery without any substitution of opioids, additional local anaesthetics, or sedatives. Results In 20 patients, 40 blocks were performed with a success rate of 95% (n=38). The failure rate was 5% (n=2) and no conversion to general anaesthesia was needed. The mean duration of the block was 14.1 h (sd 6.9). Conclusions The use of ultrasound guidance to perform spermatic cord block is feasible and has a high success rate. Our new approach may become a suitable alternative to neuraxial or general anaesthesia especially in the ambulatory surgical setting. Registry: International Standard Randomised Controlled Trial Number Register; www.controlled-trials.com; Registry Nr.: ISRCTN4464781

Two-Fluid 2.5D MHD-Code for Simulations in the Solar Atmosphere

We investigate magnetic reconnection due to the evolution of magnetic flux tubes in the solar chromosphere. We developed a new numerical two-fluid magnetohydrodynamic (MHD) code which will perform a 2.5D simulation of the dynamics from the upper convection zone up to the transition region. Our code is based on the Total Variation Diminishing Lax-Friedrichs scheme and makes use of an alternating-direction implicit method, in order to accommodate the two spatial dimensions. Since we apply a two-fluid model for our simulations, the effects of ion-neutral collisions, ionization/recombination, thermal/resistive diffusivity and collisional/resistive heating are included in the code. As initial conditions for the code we use analytically constructed vertically open magnetic flux tubes within a realistic stratified atmosphere. Initial MHD tests have already shown good agreement with known results of numerical MHD test problems like e.g. the Orszag-Tang vortex test

Insulin resistance in mice lacking neuronal nitric oxide synthase is related to an alpha-adrenergic mechanism.

BACKGROUND: nitric oxide (NO) plays an important role in the regulation of cardiovascular and glucose homeostasis. Mice lacking the gene encoding the neuronal isoform of nitric oxide synthase (nNOS) are insulin-resistant, but the underlying mechanism is unknown. nNOS is expressed in skeletal muscle tissue where it may regulate glucose uptake. Alternatively, nNOS driven NO synthesis may facilitate skeletal muscle perfusion and substrate delivery. Finally, nNOS dependent NO in the central nervous system may facilitate glucose disposal by decreasing sympathetic nerve activity. METHODS: in nNOS null and control mice, we studied whole body glucose uptake and skeletal muscle blood flow during hyperinsulinaemic clamp studies in vivo and glucose uptake in skeletal muscle preparations in vitro. We also examined the effects of alpha-adrenergic blockade (phentolamine) on glucose uptake during the clamp studies. RESULTS: as expected, the glucose infusion rate during clamping was roughly 15 percent lower in nNOS null than in control mice (89 (17) vs 101 (12) [-22 to -2]). Insulin stimulation of muscle blood flow in vivo, and intrinsic muscle glucose uptake in vitro, were comparable in the two groups. Phentolamine, which had no effect in the wild-type mice, normalised the insulin sensitivity in the mice lacking the nNOS gene. CONCLUSIONS: insulin resistance in nNOS null mice was not related to defective insulin stimulation of skeletal muscle perfusion and substrate delivery or insulin signaling in the skeletal muscle cell, but to a sympathetic alpha-adrenergic mechanism

Comparing chromosomal and mitochondrial phylogenies of the Indriidae (Primates, Lemuriformes)

The Malagasy primate family Indriidae comprises three genera with up to 19 species. Cytogenetic and molecular phylogenies of the Indriidae have been performed with special attention to the genus Propithecus. Comparative R-banding and FISH with human paints were applied to karyotypes of representatives of all three genera and confirmed most of the earlier R-banding results. However, additional chromosomal rearrangements were detected. A reticulated and a cladistic phylogeny, the latter including hemiplasies, have been performed. Cladistic analysis of cytogenetic data resulted in a phylogenetic tree revealing (1) monophyly of the family Indriidae, (2) monophyly of the genus Avahi, (3) sister–group relationships between Propithecus diadema and Propithecus edwardsi, and (4) the grouping of the latter with Indri indri, Propithecus verreauxi, and Propithecus tattersalli, and thus suggesting paraphyly of the genus Propithecus. A molecular phylogeny based on complete mitochondrial cytochrome b sequences of 16 species indicated some identical relationships, such as the monophyly of Avahi and the sister–group relationships of the eastern (P. diadema and P. edwardsi) to the western Propithecus species (P. verreauxi, Propithecus coquereli, and P. tattersalli). However, the main difference between the molecular and cytogenetic phylogenies consists in an early divergence of Indri in the molecular phylogeny while in the chromosomal phylogeny it is nested within Propithecus. The similarities and differences between molecular and cytogenetic phylogenies in relation to data on the species’ geographic distributions and mating systems allow us to propose a scenario of the evolution of Indriidae. Chromosomal and molecular processes alone or in combination created a reproductive barrier that was then followed by further speciation processes

The effects of disk and dust structure on observed polarimetric images of protoplanetary disks

Imaging polarimetry is a powerful tool for imaging faint circumstellar material. For a correct analysis of observations we need to fully understand the effects of dust particle parameters, as well as the effects of the telescope, atmospheric seeing, and assumptions about the data reduction and processing of the observed signal. Here we study the major effects of dust particle structure, size-dependent grain settling, and instrumental properties. We performed radiative transfer modeling using different dust particle models and disk structures. To study the influence of seeing and telescope diffraction we ran the models through an instrument simulator for the ExPo dual-beam imaging polarimeter mounted at the 4.2m William Herschel Telescope (WHT). Particle shape and size have a strong influence on the brightness and detectability of the disks. In the simulated observations, the central resolution element also contains contributions from the inner regions of the protoplanetary disk besides the unpolarized central star. This causes the central resolution element to be polarized, making simple corrections for instrumental polarization difficult. This effect strongly depends on the spatial resolution, so adaptive optics systems are needed for proper polarization calibration. We find that the commonly employed homogeneous sphere model gives results that differ significantly from more realistic models. For a proper analysis of the wealth of data available now or in the near future, one must properly take the effects of particle types and disk structure into account. The observed signal depends strongly on the properties of these more realistic models, thus providing a potentially powerful diagnostic. We conclude that it is important to correctly understand telescope depolarization and calibration effects for a correct interpretation of the degree of polarization.Comment: Accepted for publication in A&

Scale invariance of a diodelike tunnel junction

We measure the current vs voltage (I-V) characteristics of a diodelike tunnel junction consisting of a sharp metallic tip placed at a variable distance d from a planar collector and emitting electrons via electric-field assisted emission. All curves collapse onto one single graph when I is plotted as a function of the single scaling variable Vd^{-\lambda}, d being varied from a few mm to a few nm, i.e., by about six orders of magnitude. We provide an argument that finds the exponent {\lambda} within the singular behavior inherent to the electrostatics of a sharp tip. A simulation of the tunneling barrier for a realistic tip reproduces both the scaling behavior and the small but significant deviations from scaling observed experimentally.Comment: 6 pages, 6 figures. Accepted for publication in Physical Review

Molecular phylogeny and taxonomic revision of the sportive lemurs (Lepilemur, Primates)

BACKGROUND: The number of species within the Malagasy genus Lepilemur and their phylogenetic relationships is disputed and controversial. In order to establish their evolutionary relationships, a comparative cytogenetic and molecular study was performed. We sequenced the complete mitochondrial cytochrome b gene (1140 bp) from 68 individuals representing all eight sportive lemur species and most major populations, and compared the results with those obtained from cytogenetic studies derived from 99 specimens. RESULTS: Interspecific genetic variation, diagnostic characters and significantly supported phylogenetic relationships were obtained from the mitochondrial sequence data and are in agreement with cytogenetic information. The results confirm the distinctiveness of Lepilemur ankaranensis, L. dorsalis, L. edwardsi, L. leucopus, L. microdon, L. mustelinus, L. ruficaudatus and L. septentrionalis on species level. Additionally, within L. ruficaudatus large genetic differences were observed among different geographic populations. L. dorsalis from Sahamalaza Peninsula and from the Ambanja/Nosy Be region are paraphyletic, with the latter forming a sister group to L. ankaranensis. CONCLUSION: Our results support the classification of the eight major sportive lemur taxa as independent species. Moreover, our data indicate further cryptic speciation events within L. ruficaudatus and L. dorsalis. Based on molecular data we propose to recognize the sportive lemur populations from north of the Tsiribihina River, south of the Betsiboka River, and from the Sahamalaza Peninsula, as distinct species

Eteokles in Spain? On Brecht’s Mein Bruder war ein Flieger

One of Bertolt Brecht’s most famous poems, Mein Bruder war ein Flieger, is often invoked as a manifesto for pacifist ideals, but some essential questions (who is the lyric I? what is the literal meaning of the poem?) have hardly received any attention. By evoking the poem’s nature as a Kinderlied, the context of its first publication, and its relationship with Brecht’s play Die Gewehre der Frau Carrar, this article tentatively identifies the source of its final pointe in a famous passage of Aeschylus’ Seven against Thebes, thereby suggesting—on the basis of textual comparisons—an example of far-reaching, ideological Antikerezeption in Brecht’s oeuvre, working all the way down to his Kalendergeschichten and to his Antigone