Immature teratoma of the tectum mesencephali with histopathological detection of rudimentary eye anlage in a 3‐year‐old boy: Report of a rare case

Intracranial teratoma is a rare neoplasm derived from omnipotent germinal cells that can contain mesoderm, endoderm and/or ectoderm layer tissue. Histologically teratomas are characterized by abnormal structures like teeth or bone that can be further subdivided into mature and immature according to the presence of incompletely differentiated tissue. Characteristic intracranial teratomas are space‐occupying lesions in the pineal region and often present with hydrocephalic symptoms due to aqueduct stenosis. A 3‐year‐old boy presented with a peracute hemiparesis, fatigue and speech deficit. MRI diagnostics showed a cystic, partially solid, inhomogeneous contrast‐enhancing formation at the top of the tectum mesencephali with consecutive aqueduct compression. The patient underwent a sub‐occipital craniotomy via a supracerebellar approach and complete resection was achieved. The histopathological examination mainly showed mature tissue of ectodermal, mesodermal and endodermal origin. However, small areas of undifferentiated neuroectodermal tissue within an optic vesicle formation were detected, leading to the diagnosis of an immature teratoma. In due course, the patient was discharged in good health without neurological deficits. To our knowledge, optic vesicle‐containing intracranial germ cell tumors are extremely rare. Here we report a unique case with immature neuroectodermal tissue within an optic vesicle formation in an otherwise mature teratoma.     

Intraspecies Transfer of the Chromosomal Acinetobacter baumannii blaNDM-1 Carbapenemase Gene

The species Acinetobacter baumannii is one of the most important multidrug-resistant human pathogens. To determine its virulence and antibiotic resistance determinants, the genome of the nosocomial bla_NDM-1-positive A. baumannii strain R2090 originating from Egypt was completely sequenced. Genome analysis revealed that strain R2090 is highly related to the community-acquired Australian A. baumannii strain D1279779. The two strains belong to sequence type 267 (ST267). Isolate R2090 harbored the chromosomally integrated transposon Tn125 carrying the carbapenemase gene bla_NDM-1 that is not present in the D1279779 genome. To test the transferability of the metallo-β-lactamase (MBL) gene region, the clinical isolate R2090 was mated with the susceptible A. baumannii recipient CIP 70.10, and the carbapenem-resistant derivative R2091 was obtained. Genome sequencing of the R2091 derivative revealed that it had received an approximately 66-kb region comprising the transposon Tn125 embedding the bla_NDM-1 gene. This region had integrated into the chromosome of the recipient strain CIP 70.10. From the four known mechanisms for horizontal gene transfer (conjugation, outer membrane vesicle-mediated transfer, transformation, and transduction), conjugation could be ruled out, since strain R2090 lacks any plasmid, and a type IV secretion system is not encoded in its chromosome. However, strain R2090 possesses three putative prophages, two of which were predicted to be complete and therefore functional. Accordingly, it was supposed that the transfer of the resistance gene region from the clinical isolate R2090 to the recipient occurred by general transduction facilitated by one of the prophages present in the R2090 genome. Hence, phage-mediated transduction has to be taken into account for the dissemination of antibiotic resistance genes within the species A. baumannii.     

In vivo requirement of TGF-β/GDNF cooperativity in mouse development: focus on the neurotrophic hypothesis

Neurotrophic factors are well-recognized extracellular signaling molecules that regulate neuron development including neurite growth, survival and maturation of neuronal phenotypes in the central and peripheral nervous system. Previous studies have suggested that TGF-β plays a key role in the regulation of neuron survival and death and potentiates the neurotrophic activity of several neurotrophic factors, most strikingly of GDNF. To test the physiological relevance of this finding, TGF-β2/GDNF double mutant (d-ko) mice were generated. Double mutant mice die at birth like single mutants due to kidney agenesis (GDNF−/−) and congential cyanosis (TGF-β2−/−), respectively. To test for the in vivo relevance of TGF-β2/GDNF cooperativity to regulate neuron survival, mesencephalic dopaminergic neurons, lumbar motoneurons, as well as neurons of the lumbar dorsal root ganglion and the superior cervical ganglion were investigated. No loss of mesencephalic dopaminergic neurons was observed in double mutant mice at E18.5. A partial reduction in neuron numbers was observed in lumbar motoneurons, sensory and sympathetic neurons in GDNF single mutants, which was further reduced in TGF-β2/GDNF double mutant mice at E18.5. However, TGF-β2 single mutant mice showed no loss of neurons. These data point towards a cooperative role of TGF-β2 and GDNF with regard to promotion of survival within the peripheral motor and sensory systems investigated.     

Mechanically functional amyloid fibrils in the adhesive of a marine invertebrate as revealed by Raman spectroscopy and atomic force microscopy

Amyloid fibrils are primarily known in a pathogenic context for their association with a wide range of debilitating human diseases. Here we show a marine invertebrate (Entobdella soleae) utilizes functional amyloid fibrils comparable to those of a unicellular prokaryote (Escherichia coli). Thioflavin-T binding and Raman spectroscopy provided evidence for the presence of amyloid in the adhesive of Entobdella soleae. We elucidated that for these two very different organisms, amyloid fibrils provide adhesive and cohesive strength to their natural adhesives. Comparing the nanoscale mechanical responses of these fibrils with those of pathogenic amyloid by atomic force microscopy revealed that the molecular level origin of the cohesive strength was associated with the generic intermolecular β-sheet structure of amyloid fibrils. Functional adhesive residues were found only in the case of the functional amyloid. Atomic force microscopy provided a useful means to characterize the internal structural forces within individual amyloid fibrils and how these relate to the mechanical performance of both functional and pathogenic amyloid. The mechanistic link of amyloid-based cohesive and adhesive strength could be widespread amongst natural adhesives, irrespective of environment, providing a new strategy for biomimicry and a new source of materials for understanding the formation and stability of amyloid fibrils more generally.     

Association of serum 25-hydroxyvitamin D (25-OHD) concentrations with maternal sex steroids and IGF-1 hormones during pregnancy

Background  

Vitamin D may influence circulating levels of sex steroid hormones in women during reproductive life, but associations in pregnant women have not been explored.