Axial rotation in rat embryos: Morphological analysis and microsurgical study on the role of the allantois

Teratology ◽  
1995 ◽  
Vol 51 (2) ◽  
pp. 94-106 ◽  
Author(s):  
Masahiko Fujinaga ◽  
Brian B. Hoffman ◽  
Jeffrey M. Baden
Keyword(s):  
Morphological Analysis ◽  
Axial Rotation ◽  
Rat Embryos

The mechanism of axial rotation in the rat embryo: an experimental study in vitro

Development ◽  
1971 ◽  
Vol 25 (2) ◽  
pp. 189-201
Author(s):  
E. M. Deuchar
Keyword(s):  
Experimental Study ◽  
Axial Rotation ◽  
Watch Glass ◽  
Rat Embryo ◽  
Amniotic Cavity ◽  
Rat Embryos ◽  
Marked Inhibition ◽  
Cervical Level

Axial rotation has been studied in 9- to 11-day rat embryos grown in culture by New's watch-glass technique. Unlike the mouse, the rat embryo rotates towards its right side and rotation starts with the head end only. The twist then passes caudaiwards until the whole axis has reversed its dorsoventral orientation and curvature. Contractions in cervical and cardiac regions appear to initiate the rotation. Posterior parts of 9- and 10-day embryos, isolated by transections at mid-trunk or cervical levels, show much less ability to rotate than unoperated controls: the frequencies of fully turned, partially turned and unturned embryos have been compared between control and experimental groups and show significant differences. There is more marked inhibition of rotation when the operation is performed at 9 days than at 10 days, and more with cervical than with mid-trunk transections. In all, 67 % of embryos transected at the mid-trunk level and 98 % transected at the cervical level were unable to rotate the posterior parts. Extrusion of embryos from the amniotic cavity also resulted in abnormal or incomplete axial rotation. The role of the membranes in facilitating rotation is discussed briefly.

Hypothalamo-pituitary control of the cell-mediated immunity in rat embryos: role of LHRH in regulation of lymphocyte proliferation

2000 ◽  
Vol 47 (1) ◽  
pp. 17-32 ◽  
Author(s):  
L.A Zakharova ◽  
I.V Malyukova ◽  
E.V Proshlyakova ◽  
A.A Potapova ◽  
A.Y Sapronova ◽  
...  
Keyword(s):  
Lymphocyte Proliferation ◽  
Cell Mediated Immunity ◽  
Rat Embryos

A possible role of the nestin protein in the developing central nervous system in rat embryos

1996 ◽  
Vol 723 (1-2) ◽  
pp. 177-189 ◽  
Author(s):  
Motoko Matsuda ◽  
Ritsuko Katoh-Semba ◽  
Hiroshi Kitani ◽  
Yasuhiro Tomooka
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Rat Embryos

scholarly journals Genome-wide fitness assessment during diurnal growth reveals an expanded role of the cyanobacterial circadian clock protein KaiA

2018 ◽  
Vol 115 (30) ◽  
pp. E7174-E7183 ◽  
Author(s):  
David G. Welkie ◽  
Benjamin E. Rubin ◽  
Yong-Gang Chang ◽  
Spencer Diamond ◽  
Scott A. Rifkin ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Continuous Light ◽  
Axial Rotation ◽  
Time Of Day ◽  
Negative Regulator ◽  
Photosynthetic Organisms ◽  
Environmental Responsiveness ◽  
Environmental Responses ◽  
Clock Protein

The recurrent pattern of light and darkness generated by Earth’s axial rotation has profoundly influenced the evolution of organisms, selecting for both biological mechanisms that respond acutely to environmental changes and circadian clocks that program physiology in anticipation of daily variations. The necessity to integrate environmental responsiveness and circadian programming is exemplified in photosynthetic organisms such as cyanobacteria, which depend on light-driven photochemical processes. The cyanobacterium Synechococcus elongatus PCC 7942 is an excellent model system for dissecting these entwined mechanisms. Its core circadian oscillator, consisting of three proteins, KaiA, KaiB, and KaiC, transmits time-of-day signals to clock-output proteins, which reciprocally regulate global transcription. Research performed under constant light facilitates analysis of intrinsic cycles separately from direct environmental responses but does not provide insight into how these regulatory systems are integrated during light–dark cycles. Thus, we sought to identify genes that are specifically necessary in a day–night environment. We screened a dense bar-coded transposon library in both continuous light and daily cycling conditions and compared the fitness consequences of loss of each nonessential gene in the genome. Although the clock itself is not essential for viability in light–dark cycles, the most detrimental mutations revealed by the screen were those that disrupt KaiA. The screen broadened our understanding of light–dark survival in photosynthetic organisms, identified unforeseen clock–protein interaction dynamics, and reinforced the role of the clock as a negative regulator of a nighttime metabolic program that is essential for S. elongatus to survive in the dark.

scholarly journals FOXD3/FOXD4 is required for the development of hindgut in the rat model of anorectal malformation

2018 ◽  
Vol 243 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Luo-Jia Wang ◽  
Wei-Lin Wang ◽  
Hong Gao ◽  
Yu-Zuo Bai ◽  
Shu-Cheng Zhang
Keyword(s):  
Animal Models ◽  
Western Blot ◽  
Real Time ◽  
Digestive Tract ◽  
Anorectal Malformation ◽  
Aberrant Expression ◽  
Strong Basis ◽  
Rat Embryos ◽  
Ethylene Thiourea

Congenital anorectal malformation is the most common digestive tract malformation in newborns. It has been reported that FOXD3/FOXD4, a forkhead transcription factor, regulates the generation, migration, and differentiation of neural crest cells. However, whether FOXD3/FOXD4 takes part in anorectal malformation remains unclear. In the present study, we used ethylene thiourea to induce the animal models of anorectal malformation in rat embryos and to interrogate the role of FOXD3/FOXD4 in anorectal malformation pathogenesis. Hindgut samples of the animal models were collected at E15, E17, E19, and E21 days of age. The expression of FOXD3/FOXD4 was detected by immunohistochemistry, western blot, and quantitative real-time fluorescence PCR. By immunohistochemical staining, FOXD3/FOXD4 was observed in epithelial cells of the rectum and the anus both in normal and rat embryos with anorectal malformation. Expression level analysis by western blot indicated that FOXD3/FOXD4 expression increased in ethylene thiourea-induced anorectal malformation groups. mRNA expression as determined by quantitative real-time fluorescence PCR analysis was consistent with the western blot results. Tentative conclusions were drawn that FOXD3/FOXD4 is expressed in the hindgut in rat embryos and is upregulated in anorectal malformation. FOXD3/FOXD4 is required for the development of the hindgut, and its aberrant expression may be an important factor leading to the incidence of anorectal malformation. Impact statement Congenital anorectal malformation (ARM) is the most common digestive tract malformation in newborns. The pathophysiological ground remains unclear. In this study, we used animal models of ARM for the first time to interrogate the role of FOXD3/FOXD4 in ARM pathogenesis. The animal models of ARM were successfully induced by ethylene thiourea (ETU) in rat embryos providing a strong basis for pathogenesis study of this disease. Expression analysis of FOXD3/FOXD4 was carried out in these models, and the results shape a deeper understanding of FOXD3/FOXD4 being required for the normal development of the hindgut. The aberrant expression of FOXD3/FOXD4 may be an important factor leading to ARM incidence.

Magnetic Resonance Imaging in Non-Traumatic Canalicular Peripheral Neuropathy of the Arm

1998 ◽  
Vol 11 (1) ◽  
pp. 39-42
Author(s):  
F.A. Lupo ◽  
A. Paladini
Keyword(s):  
Morphological Analysis ◽  
Morphological Changes ◽  
Clinical Syndrome ◽  
Nerve Lesion ◽  
Resonance Imaging ◽  
Anatomical Changes ◽  
Appropriate Treatment ◽  
Electrophysiological Findings ◽  
The Cost

The term canalicular neuropathy is applied to nerve lesions arising on nerve segments passing through the osteofibrous canals or other narrow orifices and resulting in nerve compression and entrapment. We studied 31 patients referred to us for non-traumatic canalicular syndromes in the upper limbs. After clinical, electrophysiological and morphological analysis of each case, we emphasize the role of MR imaging in establishing prognosis and selecting treatment. Anatomosurgical specimens correlated well with MR features, whereas there was little correlation between electrophysiological severity and anatomical changes. In summary, canalicular neuropathy is a clinical syndrome. The aim of MR investigation is to document the morphological changes which will serve to institute appropriate treatment. When patients have clinical and electrophysiological evidence of neuropathy without MR demonstration of the nerve lesion, therapy will be conservative, thus saving the cost and risk of surgery. On the other hand, when clinical and electrophysiological findings are flanked by MR demonstration of the neuropathy, the disease is known to be advanced and surgery will be indicated to prevent neurotmesis.

Role of glutathione and hsp 70 in the acquisition of thermotolerance in postimplantation rat embryos

Teratology ◽  
1991 ◽  
Vol 43 (3) ◽  
pp. 229-239 ◽  
Author(s):  
Craig Harris ◽  
Mont R. Juchau ◽  
Philip E. Mirkes
Keyword(s):  
Hsp 70 ◽  
Rat Embryos

Word and Paradigm Morphology

2018 ◽  
pp. 264-284
Author(s):  
James P. Blevins ◽  
Farrell Ackerman ◽  
Rob Malouf
Keyword(s):  
Internal Structure ◽  
Predictive Value ◽  
Morphological Analysis ◽  
Analytic Approach ◽  
Learning Theories ◽  
Morphological Organization ◽  
External Organization ◽  
Morphological System ◽  
Morphological Patterns

There has been a broad resurgence in word-based approaches and the reconceptualization of classical ‘word and paradigm’ (WP) approaches as general models of morphological analysis. WP models are well adapted to the description and analysis of complex morphological patterns, most transparently clear in inflection. Modern WP models demonstrate how morphological organization is fundamentally implicational: the central role of words (and paradigms) reflects their predictive value in a morphological system. Understanding the nature of morphological organization, within and across languages, requires exploration of the fundamental elements of implicational relations. Descriptively this involves identifying the internal structure of words and the ways this structure facilitates an external organization into patterns of relatedness. Theoretically, it is necessary to identify analytic tools appropriate for specifying and quantifying word-internal and word-external organization. This type of analytic approach encourages the investigation of the types of learning theories that may play a role in determining the patterns observed to occur and thereby help to explain their learnability.

Absence of Fibrinogen in Afibrinogenemia Results in Large but Loosely Packed Thrombi under Flow Conditions

2001 ◽  
Vol 85 (04) ◽  
pp. 736-742 ◽  
Author(s):  
Ya-Ping Wu ◽  
Martin IJsseldijk ◽  
Jaap Zwaginga ◽  
Jan Sixma ◽  
Philip de Groot ◽  
...  
Keyword(s):  
Morphological Analysis ◽  
Surface Coverage ◽  
Thrombus Formation ◽  
Flow Conditions ◽  
Thrombotic Complications ◽  
Platelet Thrombus ◽  
The Difference ◽  
Adhesive Proteins ◽  
Lamellipodia Formation

SummaryWe studied the role of fibrinogen in platelet thrombus formation under flow on adhesive proteins using afibrinogenemic blood (LMWH anticoagulated) in a perfusion system. Perfusions with afibrinogenemic blood showed strong increased surface coverage and thrombus volume that normalized upon addition of fibrinogen. Similar studies using citrate anticoagulated blood showed that this was due to fibrinogen and not fibrin. Morphological analysis showed that afibrinogenemic thrombi were loosely packed and consisted mainly of dendritic platelets that contacted one another through filopodia. However, in the presence of fibrinogen, platelets formed lamellipodia and spread out on top of one another. Studies with radiolabeled platelets showed similar numbers of platelets in both conditions demonstrating that the difference is one of packing and the larger size is due to absence of lamellipodia formation and spreading. The found increased thrombus size and loosely packed platelets might help to understand thrombotic complications sometimes seen in afibrinogenemia patients.

Morphological analysis of the role of the neural tube and notochord in the development of somites

1995 ◽  
Vol 192 (5) ◽  
Author(s):  
Shigeki Hirano ◽  
Masao Norita ◽  
Reiji Hirako ◽  
Noriko Kajita
Keyword(s):  
Neural Tube ◽  
Morphological Analysis
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