New Rugosochonetidae (Brachiopoda) from the upper Bashkirian and Moscovian of the Cantabrian Mountains (N Spain).

The Rugosochonetidae are widely spread in the Carboniferous of the Cantabrian Mountains and they have often been described or cited by previous authors. In this paper we present a study of the Rugosochonetidae found in upper Bashkirian and Moscovian (Pennsylvanian) rocks from the Cantabrian Mountains. The diagnosis of the family is modified in order to accommodate forms with a typical rugosochonetid ornamentation but without a dorsal median septum, which are included in the new genus Riosanetes, type genus of the new subfamily Riosanetinae. The new species Riosanetes fernandezi (type species of the new genus), Neochonetes (Neochonetes) villamaninensis, N. (N.) saenzi, N. (N.) asturianus, and N. (N.) babianus are described. The latter species is based on material previously described by us as Neochonetes acanthophorus (Girty, 1934).

Morphological and Functional Changes of Roof Plate Cells in Spinal Cord Development

The most dorsal region, or roof plate, is the dorsal organizing center of developing spinal cord. This region is also involved in development of neural crest cells, which are the source of migratory neural crest cells. During early development of the spinal cord, roof plate cells secrete signaling molecules, such as Wnt and BMP family proteins, which regulate development of neural crest cells and dorsal spinal cord. After the dorso-ventral pattern is established, spinal cord dynamically changes its morphology. With this morphological transformation, the lumen of the spinal cord gradually shrinks to form the central canal, a cavity filled with cerebrospinal fluid that is connected to the ventricular system of the brain. The dorsal half of the spinal cord is separated by a glial structure called the dorsal (or posterior) median septum. However, underlying mechanisms of such morphological transformation are just beginning to be understood. Recent studies reveal that roof plate cells dramatically stretch along the dorso-ventral axis, accompanied by reduction of the spinal cord lumen. During this stretching process, the tips of roof plate cells maintain contact with cells surrounding the shrinking lumen, eventually exposed to the inner surface of the central canal. Interestingly, Wnt expression remains in stretched roof plate cells and activates Wnt/β-catenin signaling in ependymal cells surrounding the central canal. Wnt/β-catenin signaling in ependymal cells promotes proliferation of neural progenitor and stem cells in embryonic and adult spinal cord. In this review, we focus on the role of the roof plate, especially that of Wnt ligands secreted by roof plate cells, in morphological changes occurring in the spinal cord.

Retrieval of a Leadless Transcatheter Pacemaker from the Tricuspid Valve Annulus: A Case Report

This case report describes a procedure of retrieval of a leadless transcatheter pacemaker from the right ventricle after device implantation immediately. An 80-year-old man affected by ischemic cardiomyopathy, complete AV block and atrial fibrillation was implanted with a Micra transcatheter pacing system at the median septum of the right ventricle. After tether removal, the leadless pacemaker migrated to tricuspid valve annulus. The device was successfully removed using a snare loop hooked to the proximal retrieval feature of Micra.

First report of acrotretoid brachiopod shell beds in the lower Cambrian (Stage 4) Guanshan Biota of eastern Yunnan, South China

Brachiopod shell accumulations are abundant and diverse in the lower Cambrian strata of Yunnan Province, South China, but most commonly they are composed of linguloid and acrotheloid brachiopods. Here, we describe the first record of shell beds with high-density accumulations of microscopic acrotretoid brachiopods (usually <2 mm in width) in the muddy deposits of the Wulongqing Formation (Guanshan Biota, Cambrian Stage 4) in the Wuding area of Yunnan Province. The acrotretoid shell beds from the Wulongqing Formation vary from thin mm-thick pavements to more well-developed beds, several centimeters thick. The occurrence of remarkably rich acrotretoid shell beds indicates that microscopic lingulates began to exert an important role in hardening and paving the soft-substrate seafloor during the early Cambrian evolution of Phanerozoic “mixgrounds.” The new Guanshan material is referred to a new species, Linnarssonia sapushanensis n. sp., which differs from other species of Linnarssonia mainly in having a well-developed internal pedicle tube, as well as a relatively longer dorsal median septum. The occurrence of Linnarssonia sapushanensis n. sp. in the Wulongqing Formation in eastern Yunnan extend the oldest record of the genus on the Yangtze Platform of South China back to at least Cambrian Stage 4.UUID: http://zoobank.org/3e0c3878-6ce2-4eed-87bf-e39647c310c4

Proteoglycan (Keratan Sulfate) Barrier in Developing Human Forebrain Isolates Cortical Epileptic Networks From Deep Heterotopia, Insulates Axonal Fascicles, and Explains Why Axosomatic Synapses Are Inhibitory

Axons from deep heterotopia do not extend through U-fibers, except transmantle dysplasias. Keratan sulfate (KS) in fetal spinal cord/brainstem median septum selectively repels glutamatergic axons while enabling GABAergic commissural axons. Immunocytochemical demonstration of KS in neocortical resections and forebrain at autopsy was studied in 12 fetuses and neonates 9–41 weeks gestational age (GA), 9 infants, children, and adolescents and 5 patients with focal cortical dysplasias (FCD1a). From 9 to 15 weeks GA, no KS is seen in the cortical plate; 19-week GA reactivity is detected in the molecular zone. By 28 weeks GA, patchy granulofilamentous reactivity appears in extracellular matrix and adheres to neuronal somata with increasing intensity in deep cortex and U-fibers at term. Perifascicular KS surrounds axonal bundles of both limbs of the internal capsule and within basal ganglia from 9 weeks GA. Thalamus and globus pallidus exhibit intense astrocytic reactivity from 9 weeks GA. In FCD1a, U-fiber reactivity is normal, discontinuous or radial. Ultrastructural correlates were not demonstrated; KS is not electron-dense. Proteoglycan barrier of the U-fiber layer impedes participation of deep heterotopia in cortical epileptic networks. Perifascicular KS prevents aberrant axonal exit from or entry into long and short tracts. KS adhesion to neuronal somatic membranes may explain inhibitory axosomatic synapses.

Gnathopalystes aureolus (He & Hu, 2000): new combination for Pseudopoda aureola (Araneae, Sparassidae), with the first description of the female from Hainan Island, China

The taxonomic status of Pseudopodaaureola (He &amp; Hu, 2000) is revised based on the re-examination of the type specimen and fresh material collected from the type locality. The cheliceral dentition, with a large denticle field between two anterior and three posterior teeth, the male palps with simple RTA arising distally, narrow, not filiform embolus and sheet-like membranous conductor, and the female epigyne with a visible median septum indicate that the species does not belong to Pseudopoda or to the originally assigned genus, Heteropoda. Based on these characters, the species is here transferred to Gnathopalystes. The male is redescribed and the female is described and illustrated for the first time.

Altaethyrella (Brachiopoda) from the Late Ordovician of the Tarim Basin, Northwest China, and its significance

Altaethyrella tarimensis, a new species of rhynchonellide brachiopod, is described from the late Katian (Late Ordovician) Hadabulaktag Formation in the Kuruktag region of Xinjiang, Northwest China on the northeastern edge of the Tarim Basin. Serial sections of the shell clearly show no dorsal median septum or septalium in the dorsal valve, and no spiralia or atrypide-style crura. Like other species of the genus, A. tarimensis n. sp. exhibits a high degree of intraspecific variation, including variations in shell shape and size, number of ribs in the sulcus at the anterior, and degree of asymmetry. The discovery of Altaethyrella in Tarim has important paleogeographic implications, indicating a close relationship between the Late Ordovician brachiopod faunas of Tarim and those of the Kazakh terranes and North and South China paleoplates, supporting a recently published paleogeographic projection that places Tarim near the Chu-Ili terrane during the Late Ordovician. The abundant large biconvex shells of A. tarimensis n. sp. would have provided a firm substrate for encrusting filter feeders like bryozoans to establish on the Kuruktag Platform.UUID: http://zoobank.org/df8843cd-4db0-48e7-ba03-bf0ce81c4f01

The use of modern ultrasound tridimensional techniques for the evaluation of fetal cerebral midline structures – a practical approach.

Fetal central nervous system midline structures represent an essential landmark for the confirmation of normality or for the identification of severe pathology. The ultrasound examination of the fetal brain using modern 3D techniques allows the crea- tion of high sensitivity reconstructions. The facility of 3D volume acquisition permits the identification of corpus callosum, median septum, cavum septi pellucid and cerebellar vermis even in difficult cases. The examination should rely on both static (3D) and dynamic acquisition (4D). The use of a practical ultrasound protocol in clinical settings ensures the visualization of the midline cerebral structures in the vast majorities of fetuses. In selected cases MRI can be performed.