Characterization of the Transition Zone in Short Segment Hirschsprung Disease Using Calretinin Immunostaining

Introduction: The detailed expression pattern of calretinin immunohistochemistry in the transition zone (TZ) of Hirschsprung disease (HSCR) has not yet been reported. This study aims to examine the value of calretinin immunohistochemistry for more accurately determining the distal and proximal border of the TZ in short segment HSCR. Methods: Specimens of pull-through surgery from 51 patients with short form of HSCR were analyzed on two longitudinal strips using hematoxylin and eosin (H&E) staining and calretinin immunohistochemistry. Results: In all but two patients, the first appearance of calretinin expression was seen on mucosal nerve fibers before the appearance of any ganglion cells, indicating the distal border of the TZ. The maximum distance between the distal border of the TZ and the proximal border of the TZ, defined by ganglion cells in a normal density on H&E stained sections, a strong calretinin expression on mucosal nerve fibers and in >80% of submucosal and myenteric ganglion cells, with no nerve hypertrophy and absence of ganglionitis was 60 mm. Conclusion: The distal border of the TZ is characterized by calretinin positive intramucosal neurites in nearly all of short form of HSCR and not by calretinin expression on ganglion cells.

Two new species of Euphaea Selys, 1840 (Odonata: Zygoptera: Euphaeidae) from northern Western Ghats, India

Two new species of the damselfly genus Euphaea Selys, 1840 (Odonata: Euphaeidae) are described from the Western Ghats of Satara District, Maharashtra, distinguished by their distinct morphology and coloration. E. thosegharensis Sadasivan & Bhakare sp. nov. is similar to E. cardinalis (Fraser, 1924), but is distinguished by the extensor and flexor surface of all femora black while all femora bright red in E. cardinalis; apical fourth of Hw black while apical half of Hw black in E. cardinalis; genae reddish-orange, black in E. cardinalis; a tuft of sparse stub black hair on either side of tergite of S9 while both S8 and S9 with tufts of long ventral hairs in E. cardinalis. Male genital vesicle matt black, with distal border rounded angles, while vesicle black and hexagonal in shape with rounded angles in E. cardinalis and S9 twice the length of S10, while S9 and S10 of equal length in E. cardinalis. E. pseudodispar Sadasivan & Bhakare sp. nov., is very close to E. dispar (Rambur, 1842), but is differentiated easily by the absence of yellow patch on legs as in E. dispar; only apical fifth of Hw black; genae being yellowish-white, while black in E. dispar; male genital vesicle brownish-black & rhomboid-shaped and with no transverse rugosities while black with distal border rounded and with fine transverse rugosities in E. dispar; penis with single seta on each side while E. dispar has three pairs; sternite of S9 very prominently extending ventrally like a beak in comparison with E. dispar. We have identified additional morphological characters useful in taxonomy of Euphaea of the Western Ghats for example, tufts of ventral hairs on terminal abdominal segments genital vesicle, penile structure of males and sternite of S9 in the males, and vulvar scales of females. A taxonomic key to all known species of genus Euphaea of the Western Ghats is also provided.

The migratory pathways of the cells that form the endocardium, dorsal aortae, and head vasculature in the mouse embryo

BackgroundVasculogenesis in amniotes is often viewed as two spatially and temporally distinct processes, occurring in the yolk sac and in the embryo. However, the spatial origins of the cells that form the primary intra-embryonic vasculature remain uncertain. In particular, do they obtain their haemato-endothelial cell fate in situ, or do they migrate from elsewhere? Recently developed imaging techniques, together with new Tal1 and existing Flk1 reporter mouse lines, have allowed us to investigate this question directly, by visualising cell trajectories live and in three dimensions.ResultsWe describe the pathways that cells follow to form the primary embryonic circulatory system in the mouse embryo. In particular, we show that Tal1-positive cells migrate from within the yolk sac, at its distal border, to contribute to the endocardium, dorsal aortae and head vasculature. Other Tal1 positive cells, similarly activated within the yolk sac, contribute to the yolk sac vasculature. Using single-cell transcriptomics and our imaging, we identify VEGF and Apela as potential chemo-attractants that may regulate the migration into the embryo. The dorsal aortae and head vasculature are known sites of secondary haematopoiesis; given the common origins that we observe, we investigate whether this is also the case for the endocardium. We discover cells budding from the wall of the endocardium with high Tal1 expression and diminished Flk1 expression, indicative of an endothelial to haematopoietic transition.ConclusionsIn contrast to the view that the yolk sac and embryonic circulatory systems form by two separate processes, our results indicate that Tal1-positive cells from the yolk sac contribute to both vascular systems. It may be that initial Tal1 activation in these cells is through a common mechanism.

CPD article: Radiographic interpretation of the navicular bone: a review

Navicular syndrome (navicular disease) plays a major role in the equine industry as a chronic, degenerative, and often career-limiting disease process, affecting a variety of breeds of horses. In addition to clinical signs and diagnostic analgesia, diagnostic imaging plays a key role in the identification of this disease process; radiography is the most widely used imaging modality. In addition to their clinical utility, foot radiographs are a standard element of most pre-purchase examinations. Good radiographic quality and positioning are necessary for accurate interpretation. Radiographic lesions of the navicular bone, such as sclerosis, enlarged synovial invaginations, distal border fragments and flexor cortical erosions, are important to identify and understand because of their potential role in the disease process. This article reviews an approach to radiological evaluation and interpretation of lesions affecting the navicular bone.

Super-resolution microscopy reveals coupling between mammalian centriole subdistal appendages and distal appendages

Subdistal appendages (sDAPs) are centriolar elements that are observed proximal to the distal appendages (DAPs) in vertebrates. Despite the obvious presence of sDAPs, structural and functional understanding of them remains elusive. Here, by combining super-resolved localization analysis and CRISPR-Cas9 genetic perturbation, we find that although DAPs and sDAPs are primarily responsible for distinct functions in ciliogenesis and microtubule anchoring, respectively, the presence of one element actually affects the positioning of the other. Specifically, we find dual layers of both ODF2 and CEP89, where their localizations are differentially regulated by DAP and sDAP integrity. DAP depletion relaxes longitudinal occupancy of sDAP protein ninein to cover the DAP region, implying a role of DAPs in sDAP positioning. Removing sDAPs alter the distal border of centrosomal γ-tubulins, illustrating a new role of sDAPs. Together, our results provide an architectural framework for sDAPs that sheds light on functional understanding, surprisingly revealing coupling between DAPs and sDAPs.

AN ANATOMICAL STUDY OF SUPERFICIAL PALMAR ARCH IN WESTERN RAJASTHAN POPULATION

The supercial palmar arch is an anastomosis formed mainly by the Ulnar artery with variable contribution from branches of radial Artery. It passes medial to the hook of the hamate, then curves laterally to form an arch that is convex distally and level with a transverse line through the distal border of the fully extended pollicies base. About a third of the supercial palmar arches are formed by the ulnar artery alone; a further third are completed by the supercial palmar branch of the radial artery; and a third by the arteria radialis indicis, a branch of either arteria princeps pollicis or the median artery. The supercial palmar arch is covered by palmaris brevis and the palmar aponeurosis and it is supercial to exor digiti minimi, branches of the median nerve and the long exor tendons and lumbricals.

How Close Are the Volar Wrist Ligaments to the Distal Edge of the Pronator Quadratus? An Anatomical Study

Background: This cadaveric study defines the interval distance between the proximal insertion of the volar wrist ligaments and the distal edge of the pronator quadratus on the distal radius. It is important to be aware of this distance during surgical dissection for placement of volar locking plates for wrist fractures. Disruption of the volar wrist ligament insertion may have adverse biomechanical consequences such as carpal instability, which can lead to pain and eventually wrist arthritis. Methods: Thirteen cadaveric wrists were dissected using the trans-flexor carpi radialis volar approach to identify relevant anatomy. The distance between the distal border of the pronator quadratus and the most proximal insertion of the volar wrist ligaments was measured. Results: The average distance between the pronator quadratus and the proximal insertion of the volar wrist ligaments was 5 mm, with a standard deviation of 2 mm. Conclusions: The volar wrist ligaments insert quite near the distal end of the pronator quadratus. Surgeons should be cognizant of the proximity of the volar wrist ligaments and be judicious with subperiosteal stripping of the distal fragment during volar plating procedures.

Development of the outflow tract

The definitive cardiac outflow tracts have three components: the intra-pericardial arterial trunks, the arterial roots, and the ventricular outflow tracts. Improved correlations between normal development and cardiac malformations can be obtained by analysing the developing outflow tract in tripartite fashion with proximal, intermediate, and distal components. When first seen, the walls of the entire outflow tract express myocardial markers. With ongoing development, the distal border regresses away from the edges of the pericardial cavity. Subsequently, the distal outflow tract becomes the intra-pericardial arterial trunks, with a protrusion from the dorsal wall of the aortic sac forming the aortopulmonary septum. The arterial valves form in the intermediate part of the outflow tract. The proximal part eventually becomes transformed into the ventricular outflow tracts, with muscularization of the proximal cushions producing the right ventricular infundibulum. This approach provides rational explanations for the congenital lesions involving the different parts of the outflow tracts.

First record of Pallenopsis fluminensis (Krøyer, 1844) (Pycnogonida: Pallenopsidae) for the coast of the state of Paraíba (northeastern Brazil)

<p align="justify">Uma espécie de picnogonídeo classificada na família Pallenopsidae Fry, 1978 e no gênero Pallenopsis Wilson, 1881 é registrada neste estudo para a costa do estado da Paraíba (nordeste do Brasil), com base na identificação de três espécimes fêmeas coletadas na zona infralitoral em profundidades de 12 a 34 metros. Pallenopsis fluminensis (Krøyer, 1844) é a quarta espécie de Pycnogonida registrada para a região. Até então, apenas Anoplodactylus batangensis (Helfer, 1938), A. eroticus Stock, 1968 e A. mirim Lucena, Araújo &amp; Christoffersen, 2015 haviam sido registradas para a costa da Paraíba. Pallenopsis fluminensis é diagnosticada pelo tronco com setas pequenas na borda distal de cada segmento; probóscide com setas terminais; processos laterais com pequenas setas dorsais; palpos sem setas e reduzidos a um pequeno tubérculo; quela com muitas setas, palma 1.5 vezes mais longa que larga; ovígeros com oito artículos nas fêmeas, sendo os artículos 5 e 6 subiguais, e o 8 pouco menor que o 7; e a tíbia 1 sem uma cobertura densa de setas. Até o momento, P. fluminensis é a única congênere proveniente da costa Atlântica da América do Sul sem uma densa cobertura de setas sobre a tíbia 1.</p><p align="justify"><strong>Palavras chave</strong>: Arthropoda, Chelicerata, Pantopoda, Atlântico oeste, região tropical, zona costeira.</p><p align="justify"><strong>Abstract</strong>: A pycnogonid species classified in the family Pallenopsidae Fry, 1978 and the genus Pallenopsis Wilson, 1881 is recorded in this study for the coast of the state of Paraíba in northeastern Brazil based on the identification of three female specimens collected from the infralittoral zone at depths of 12 to 34 meters. Pallenopsis fluminensis (Krøyer, 1844) is the fourth species of Pycnogonida recorded for the region. To date, only Anoplodactylus batangensis (Helfer, 1938), A. eroticus Stock, 1968 and A. mirim Lucena, Araújo &amp; Christoffersen, 2015 have been recorded for the coast of the state of Paraíba. Pallenopsis fluminensis is diagnosed by a trunk with small setae on the distal border of each segment; proboscis with terminal setae; lateral processes with small setae; palps without setae and reduced to a small knob; chela with many setae, palm 1.5 times longer than wide; ovigers with eight articles on females, articles 5 and 6 subequal and article 8 not much smaller than 7; and tibia 1 without dense cover of the setae. To date, P. fluminensis is the only congener from the Atlantic coast of South America without a dense cover of setae on tibia 1.</p><p align="justify"><strong>Key words</strong>: Arthropoda, Chelicerata, Pantopoda, Western Atlantic, tropical region, coastal zone.</p>