Reconstitutive ability of axial tissue in early rat embryos after operations and culture in vitro

Development ◽  
1975 ◽  
Vol 33 (1) ◽  
pp. 217-226
Author(s):  
E. M. Deuchar

Longitudinal incisions have been made in the axis of 10-day-old rat embryos (post-neurula stage with 5–10 pairs of somites) at mid-trunk levels, dividing the axis into right and left halves. The embryos have then been cultured in vitro by New's method and their ability to reconstitute tissues in each half has been studied. After 20 h culture at 37 °C, there was no longer any external sign of the division of the axis. Histological studies showed that in nearly all cases, however, the neural tube was duplicated in the operated region. The two neural tubes lay in close contact in the midline, and ventral to them the gut was single. Apart from four cases in which the gut roof was slightly broadened and forked, all other tissues were normal. The reconstitutive ability of the neural and gut tissue has been compared with that of amphibian and avian embryos, as observed in ‘twinning’ experiments by other workers. The apparent delay in axial rotation in the operated rat embryos, as compared with controls, is attributed to the inability of the two separated halves of the somite series to co-ordinate their contractions. Further details of the rotation process in operated embryos will be the subject of a future study.

Blood ◽  
1955 ◽  
Vol 10 (2) ◽  
pp. 145-153 ◽  
Author(s):  
MAURICE M. BLACK ◽  
JOSEPH A. PRESTON ◽  
FRANCIS D. SPEER ◽  
PHYLLIS BRENOWITZ

Abstract Tetrazolium chloride was used to visualize the in vitro dehydrogenase activity of splenic tissues from cases with and without hypersplenism. In addition, quantitative measurements of such activity were made in the presence and absence of fluoride, malonate and azide. The data indicate that spleen slices from cases of hypersplenism differed from the controls and were characterized by (a) increased endogenous dehydrogenase activity of the lymphocytes, particularly around the follicles, (b) a decreased azide stimulation in those cases having an initial thrombocytopenia which responded to splenectomy, and (c) a decreased fluoride stimulation in those cases having an initial leukopenia which responded to splenectomy. Routine histological studies confirmed other reports that a constant structural feature of the spleen in hypersplenism is a perifollicular lymphocytic rimming.


Development ◽  
1966 ◽  
Vol 15 (3) ◽  
pp. 387-395
Author(s):  
M. M. Turbow

Trypan blue is known to produce embryonic abnormalities in a wide variety of animals, including rats (Gillman, Gilbert, Gillman & Spence, 1948), mice (Waddington & Carter, 1953; Hamburgh, 1954), amphibians (Waddington & Perry, 1956), chickens (Beaudoin & Wilson, 1958;Stéphan & Sutter, 1961), rabbits (Ferm, 1956), and hamsters (Ferm, 1958). Studies on the teratogenic action of this dye have also been made in culture (Mulherkar, 1960). Since the first observation of the teratogenic action of trypan blue in rat embryos (Gillman et al. 1948), two questions that have remained unanswered are (1) whether the dye acts directly on the embryo or via the maternal system, and (2) what determines the period during which the rat embryo is most sensitive to the dye.


Development ◽  
1965 ◽  
Vol 13 (1) ◽  
pp. 119-128
Author(s):  
Joseph Butros

The posterior segment isolated from definitive streak or head process blastoderms by a transverse cut 0·5–0·2 mm. posterior to Hensen's node seems to be a suitable experimental object for the study of differentiation. Its limited prospective significance and potency in chorioallantoic transplantation or in vitro compared with the versatile node has been the subject of several studies (Hunt, 1931; Willier & Rawles, 1931; Rawles, 1936; Rudnick, 1938a, b; Waddington 1933; Spratt, 1952). The present author has shown that rooster testis DNA and 5-day chick embryo DNA (0·25–0·50 mg./ml.) induce neural tubes and somitelike aggregations of the mesoderm in post-nodal explants cultured on albuminagar (Butros, 1960). When axial structures were grafted on the explants, the latter were induced to develop nephrotomes, ducts, neural folds and notochords (Butros, 1962). Improved procedures for culturing post-nodal explants, which circumvent the tendency of these pieces to form hollow vesicles, were reported recently (Butros, 1963a).


Development ◽  
1971 ◽  
Vol 25 (2) ◽  
pp. 189-201
Author(s):  
E. M. Deuchar

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.


1994 ◽  
Vol 15 (3) ◽  
pp. 134-140 ◽  
Author(s):  
Joseph R. Cass ◽  
Harry Settles

This study was undertaken to elucidate the kinematics of hindfoot instability. An axial load was applied to the inverted hindfoot. Unlike prior studies, axial rotation was not constrained. Using computerized tomography, measurements were made on the axial views of external or internal rotation of the leg, talus, and calcaneus. On the coronal views, tilting of the talus at the ankle and subtalar joints was assessed. No tilting of the talus in the mortise occurred with isolated release of the anterior talofibular (ATF) or calcaneofibular (CF) ligament. In every specimen, talar tilt occurred only after both ligaments were released, averaging 20.6°. External rotation of the leg occurred with inversion averaging 11.1° in the intact specimen. The leg averaged a further external rotation of 4.9° after ATF release and 12.8° further than the intact inverted specimens when both ligaments (ATF-CF) had been released. In earlier reports on the subject, the articular surfaces were believed to be the main constraint against tilting of the talus. In those studies, either axial rotation was constrained while inversion was allowed, or vice versa. Based on the data reported here, the ATF and the CF work in tandem to prevent tilting of the talus, and the articular surfaces do not seem to prevent tilting of the talus in the mortise.


Think India ◽  
2019 ◽  
Vol 22 (3) ◽  
pp. 72-83
Author(s):  
Tushar Kadian

Actually, basic needs postulates securing of the elementary conditions of existence to every human being. Despite of the practical and theoretical importance of the subject the greatest irony is non- availability of any universal preliminary definition of the concept of basic needs. Moreover, this becomes the reason for unpredictability of various political programmes aiming at providing basic needs to the people. The shift is necessary for development of this or any other conception. No labour reforms could be made in history till labours were treated as objects. Its only after they were started being treating as subjects, labour unions were allowed to represent themselves in strategy formulations that labour reforms could become a reality. The present research paper highlights the basic needs of Human Rights in life.


2018 ◽  
Vol 11 (2) ◽  
pp. 41-51 ◽  
Author(s):  
I. Ya. Lukasevich

The subject of the research is new tools for business financing using the initial coin offering (ICO) in the context of the development of cryptocurrencies and the blockchain technologies as their basis. The purpose of the work was to analyze the advantages and disadvantages of the ICO in comparison with traditional financial tools as well as prospects, limitations and problems of using digital financial tools. Conclusions are made in relation to possibilities, limitations and application areas of digital business financing tools, particularly in the real sector, taking into account the specifics of the Russian economy and legislation. It is shown that the main problems of using the digital financial tools are related to the economic sphere and caused by the lack of adequate approaches to evaluation of assets as well as the shortage of objective information. The problems and new tasks of corporate finance in the digital economy are defined.


1983 ◽  
Vol 22 (1) ◽  
pp. 57-61
Author(s):  
Shahrukh Rafi Khan

The book under review is a compilation of the author's articles and lectures that highlight the prominent developments in the literature on the subject of Islamic banking and inform the reader of the current state of debate on it. One of the earliest and main contributors to this topic is the author himself. The focus of this review will mainly be on "Economics of Profit-Sharing", which is the title of the fourth chapter of the book and is among his latest contributions. This chapter is a significant contribution as it is the first attempt to formalise the concept of profit sharing into an analytical model and, therefore, demands closer scrutiny. However, in the remaining chapters of the book, the author has drawn attention to some of the fine points made in the literature on this topic. Since some of these points appear to be controversial to me, I will briefly discuss them before moving on to the analytical chapter of the book.


2020 ◽  
Vol 22 (2) ◽  
pp. 1-27
Author(s):  
João Carlos Brum Torres

O artigo tem por objeto o exame de três registros de gritantes e distintos paradoxos na Doutrina do Direito de Kant. Registros feitos em tempos e contextos históricos diferentes por Friedrich Bouterwek, Marcus Willaschek e Balthazar Barbosa Filho. Bouterwek atribuiu a Kant a mais paradoxal das proposições jamais enunciadas por qualquer autor, a de que a mera ideia de soberania deve obrigar-nos a obedecer como a nosso inquestionável senhor a quem quer que se haja estabelecido como tal, sem que caiba indagar quem lhe deu o direito de comandar-nos. Willaschek aponta a incompatibilidade de duas teses centrais da doutrina kantiana: a do caráter externo dos vínculos jurídicos e a da incondicionalidade obrigacional do direito positivo, pois não é possível entender como é possível termo-nos como obrigados por imperativos jurídicos e, ao mesmo, vermo-nos internamente isentados do dever de obedecê-los. O ponto crítico de Balthazar é alegar que não pode haver na filosofia kantiana uma crítica da razão político e jurídica, simplesmente porque o conceito de imputação, base da normatividade própria dessas esferas, pressupõe uma pluralidade de agentes livres que, justamente, só pode ser uma pressuposição, pois nosso acesso à normatividade prática só pode ter lugar em primeira pessoa. No exame a que o artigo submete essas alegações, o artigo argumenta, em objeção à tese de Balthazar, que o caráter universal e categórico da força que vincula o sujeito quando confrontado com a lei moral em primeira pessoa necessariamente se desvaneceria se, ao mesmo tempo, ele não fosse tomado pela evidência de que a realidade objetiva dos princípios morais é não só instanciável, mas assegurada pela múltipla instanciação. Com relação às dificuldades levantadas por Willaschek e Bouterwek, o artigo argumenta que o princípio exeundum e statu naturali, enquanto norma metapositiva, anterior à divisão do domínio prático entre doutrina do direito e doutrina da virtude, permite ao mesmo tempo compreender a exigência de obediência ao poder constituído e a restrição das obrigações jurídico-políticas exclusivamente ao foro externo.AbstractThe object of the article is to examine three claims about three distinct and allegedly blatant paradoxes in Kant's Doctrine of Right. These three critical points had been made in distinct times and contexts by Friedrich Bouterwek, Marcus Willaschek e Balthazar Barbosa Filho. Bouterwek attributed to Kant the most paradoxical of all paradoxical propositions, the statement that by the mere idea of sovereignty we are obliged to obey as our lord who has imposed himself upon us, without questioning from where he got such right. Willaschek points out the incompatibility of two main theses of Kantian doctrine of right: the claims that the legal bounds are of external character and that they are the source of unconditional obligations, since it seems impossible to understand how it would be possible to be obliged by juridical norms and decisions and at the same time to be exempted of the internal duty of compliance. The radical objection of Professor Balthazar is the claim that in the context of Kantian Philosophy it is impossible to admit a critique of the juridical and political reason because the concept of imputation, ground of the normativity in these domains, requires not only the presupposition of free agents, but a true and secure epistemic access to them, which is, according to him, impossible considering that the moral law and the other practical principles are accessible for us only in the first person. In the course of the appraisal of such claims, the article contest that objection arguing that the universal and categorical force of the normative bound experienced by the subject when confronted with the moral law in the first person would ineluctably vanish if, at the same time, he had not been taken by the evidence that the objective reality of the moral principles is secured by multiple instancing. Regarding the difficulties raised by Willaschek and Bouterwek, the article argues that the principle exeundum e statu naturali, as a norm of meta-positive character, prior to the division of practical domains between the doctrine of right and the doctrine of virtue, is the cue both to the understanding of the requirement of unquestioning obedience to the constituted power and to the restriction of the validity of this requirement only in foro externo.


2019 ◽  
Vol 16 (5) ◽  
pp. 478-491 ◽  
Author(s):  
Faizan Abul Qais ◽  
Mohd Sajjad Ahmad Khan ◽  
Iqbal Ahmad ◽  
Abdullah Safar Althubiani

Aims: The aim of this review is to survey the recent progress made in developing the nanoparticles as antifungal agents especially the nano-based formulations being exploited for the management of Candida infections. Discussion: In the last few decades, there has been many-fold increase in fungal infections including candidiasis due to the increased number of immunocompromised patients worldwide. The efficacy of available antifungal drugs is limited due to its associated toxicity and drug resistance in clinical strains. The recent advancements in nanobiotechnology have opened a new hope for the development of novel formulations with enhanced therapeutic efficacy, improved drug delivery and low toxicity. Conclusion: Metal nanoparticles have shown to possess promising in vitro antifungal activities and could be effectively used for enhanced and targeted delivery of conventionally used drugs. The synergistic interaction between nanoparticles and various antifungal agents have also been reported with enhanced antifungal activity.


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