Memoirs: Blastopore Mesoderm and Metameric Segmentation

1885 ◽  
Vol s2-25 (97) ◽  
pp. 15-28
Author(s):  
W. H. CALDWELL
Keyword(s):  
Rapid Growth ◽  
Primitive Streak ◽  
The Body ◽  
The Other ◽  
Terminal Position ◽  
Posterior Pair ◽  
Mesoderm Formation ◽  
Anterior Pair

Facts in the development of Phoronis-- 1. The blastopore gives rise to both mouth and anus. 2. The mesoderm arises in an anterior pair of endoblastic modified diverticula, and in a posterior pair of ectoblastic diverticula connected by a few mesodermic cells derived from the middle of a primitive streak. 3. The nephridial openings to the exterior are parts of the blastopore. Preliminary interpretation suggested by these facts of the development of Phoronis-- 1. A gastraea with slit-like mouth and a pair of lateral diverticula giving rise to mesoderm was the ancestor of Phoronis. 2. The rapid growth of ectoderm in the median ventral line nearly succeeded in destroying the continuity of the primitive streak. 3. The necessity of an early attainment of a terminal position by the anus caused the ectoderm to grow more rapidly than, the emdoblast, and resulted in a division of the mesoderm into anterior and posterior parts. 4. The nephridia, which might have remained either wholly or in part with the anterior, have attached themselves entirely to the posterior mesoderm. Extension of this interpretation to the other Tripleblastiea-- 1. Phoronis is the first step towards a complete division of the blastopore. The inducing cause of such division is the elongation of the body, while the endoblast is still in an embryonic condition. 2. The division of blastopore caused the division of mesoderm. 3. The division of mesoderm results in-- i. The masking of the original mode of mesoderm formation. ii. Metameric segmentation.

Onset of the segmentation clock in the chick embryo: evidence for oscillations in the somite precursors in the primitive streak

Development ◽  
2002 ◽  
Vol 129 (5) ◽  
pp. 1107-1117 ◽  
Author(s):  
Caroline Jouve ◽  
Tadahiro Iimura ◽  
Olivier Pourquie
Keyword(s):  
Continuous Process ◽  
Notch Pathway ◽  
Primitive Streak ◽  
The Body ◽  
Paraxial Mesoderm ◽  
Segmentation Clock ◽  
Head Mesoderm ◽  
Dynamic Expression ◽  
Mesoderm Formation ◽  
Cyclic Gene

Vertebrate somitogenesis is associated with a molecular oscillator, the segmentation clock, which is defined by the periodic expression of genes related to the Notch pathway such as hairy1 and hairy2 or lunatic fringe (referred to as the cyclic genes) in the presomitic mesoderm (PSM). Whereas earlier studies describing the periodic expression of these genes have essentially focussed on later stages of somitogenesis, we have analysed the onset of the dynamic expression of these genes during chick gastrulation until formation of the first somite. We observed that the onset of the dynamic expression of the cyclic genes in chick correlated with ingression of the paraxial mesoderm territory from the epiblast into the primitive streak. Production of the paraxial mesoderm from the primitive streak is a continuous process starting with head mesoderm formation, while the streak is still extending rostrally, followed by somitic mesoderm production when the streak begins its regression. We show that head mesoderm formation is associated with only two pulses of cyclic gene expression. Because such pulses are associated with segment production at the body level, it suggests the existence of, at most, two segments in the head mesoderm. This is in marked contrast to classical models of head segmentation that propose the existence of more than five segments. Furthermore, oscillations of the cyclic genes are seen in the rostral primitive streak, which contains stem cells from which the entire paraxial mesoderm originates. This indicates that the number of oscillations experienced by somitic cells is correlated with their position along the AP axis.

Mediolateral somitic origin of ribs and dermis determined by quail-chick chimeras

Development ◽  
2000 ◽  
Vol 127 (21) ◽  
pp. 4611-4617 ◽  
Author(s):  
I. Olivera-Martinez ◽  
M. Coltey ◽  
D. Dhouailly ◽  
O. Pourquie
Keyword(s):  
Skeletal Muscles ◽  
Body Wall ◽  
Primitive Streak ◽  
Axial Skeleton ◽  
Lateral Compartment ◽  
The Body ◽  
The Other ◽  
Lateral Part ◽  
Respective Contribution ◽  
Epaxial Muscles

Somites are transient mesodermal structures giving rise to all skeletal muscles of the body, the axial skeleton and the dermis of the back. Somites arise from successive segmentation of the presomitic mesoderm (PSM). They appear first as epithelial spheres that rapidly differentiate into a ventral mesenchyme, the sclerotome, and a dorsal epithelial dermomyotome. The sclerotome gives rise to vertebrae and ribs while the dermomyotome is the source of all skeletal muscles and the dorsal dermis. Quail-chick fate mapping and diI-labeling experiments have demonstrated that the epithelial somite can be further subdivided into a medial and a lateral moiety. These two subdomains are derived from different regions of the primitive streak and give rise to different sets of muscles. The lateral somitic cells migrate to form the musculature of the limbs and body wall, known as the hypaxial muscles, while the medial somite gives rise to the vertebrae and the associated epaxial muscles. The respective contribution of the medial and lateral somitic compartments to the other somitic derivatives, namely the dermis and the ribs has not been addressed and therefore remains unknown. We have created quail-chick chimeras of either the medial or lateral part of the PSM to examine the origin of the dorsal dermis and the ribs. We demonstrate that the whole dorsal dermis and the proximal ribs exclusively originates from the medial somitic compartment, whereas the distal ribs derive from the lateral compartment.

Expression pattern of the Brachyury gene in whole-mount TWis/TWis mutant embryos

Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 913-917 ◽  
Author(s):  
B.G. Herrmann
Keyword(s):  
Gene Product ◽  
Gene Dosage ◽  
Primitive Streak ◽  
The Body ◽  
Primary Defect ◽  
Whole Mount ◽  
Mesoderm Formation ◽  
Axis Elongation ◽  
Severe Disturbance ◽  
Axial Development

The murine Brachyury (T) gene is required in mesoderm formation. Mutants carrying different T alleles show a graded severity of defects correlated with gene dosage along the body axis. The phenotypes range from shortening of the tail to the malformation of sacral vertebrae in heterozygotes, and to disruption of trunk development and embryonic death in homozygotes. Defects include a severe disturbance of the primitive streak, an early cessation of mesoderm formation and absence of the allantois and notochord, the latter resulting in an abnormality of the neural tube and somites. The T gene is expressed in nascent mesoderm and in the notochord of wild-type embryos. Here the expression of T in whole-mount mutant embryos homozygous for the T allele TWis is described. The TWis gene product is altered, but the TWis/TWis phenotype is very similar to that of T/T embryos which lack T. In early TWis/TWis embryos T expression is normal, but ceases prematurely during early organogenesis coincident with a cessation of mesoderm formation. The archenteron/node region is disrupted and the extension of the notochord precursor comes to a halt, followed by a decrease and finally a complete loss of T gene expression in the primitive streak and the head process/notochord precursor. It appears that the primary defect of the mutant embryo is the disruption of the notochord precursor in the node region which is required for axis elongation. Thus the T gene product is directly or indirectly involved in the organization of axial development.

Memoirs: The Phylogeny of the Tracheæ in Araneæ

1910 ◽  
Vol s2-54 (216) ◽  
pp. 519-563
Author(s):  
W. F. PURCELL
Keyword(s):  
Common Ancestor ◽  
Venous Blood ◽  
Great Majority ◽  
The Body ◽  
Entire Body ◽  
Tracheal System ◽  
Posterior Pair ◽  
The Common ◽  
Anterior Pair

The theoretical suggestions in the preceding paragraphs may be summed up as follows: In the first place I suppose the saccules of the second pair of lung-books to have been converted into tracheal tubules in the common ancestor of the Dysderidæ, Oonopidæ, and Caponiidæ. The resultant tracheæ then increased in size, and, as the number of the leaves of the anterior lungbooks decreased in inverse ratio, the former became the priucipal organs of respiration. The second pair of spiracles retained their position, or may even have moved slightly forwards, and the conversion oE the entapophyses into trachea? could not take place here, and would, moreover, be quite unnecessary. In the Caponiidaa the anterior pair of lungbooks were converted into tracheae in a similar manner, but at a, later period, and independently of the conversion of the posterior pair; but as the latter already provided almost the entire body with tracheæ, the anterior pair did not further increase in size. In the second place, iu the progenitor (or progenitors) of the remaining tracheate spiders, the posterior lung-books became reduced in size and effectiveness by the disappearance oE their saccules, accompanied by an increase in the number of the leaves of the anterior lung-books. Further, the posterior spiracles became approximated and united to a single spiracle, and moved towards the hinder end of the body, thereby causing the entapophyses of the tracheal segment to elongate. In this condition the Filistatidas, Sicariidse, and Palpimanidas have remained, with slight modifications, such as the division of the tracheal antechambers into branches in some forms. In the great majority of the families, however, the elongated entapophyses became transformed into a pair of medial tracheal trunks, thus producing a tracheal system consisting of four simple unbranched trunks, which is still found in some genera at least, in nearly all the families. A new factor having been introduced, viz. the presence of the respiratory entapophyses lying in the large ventral sinus containing venous blood requiring aeration, we accordingly find the second respiratory segment again taking a prominent part in the respiration in many forms, owing to the increase in size and the branching of the medial trunks, accompanied ultimately by a corresponding reduction in the size of the anterior lung-books, e. g. in the Attidæ. This method of origin of the tracheæ is independent of that of the Dysderidse and its allies, and the tracheal tubules, when present, would here not be derived from saccules, but be new formations.

scholarly journals An experimental enquiry into the factors which determine the growth and activity of the mammary glands

1906 ◽  
Vol 77 (520) ◽  
pp. 505-522 ◽  
Keyword(s):  
Rapid Growth ◽  
Experimental Methods ◽  
Mammary Glands ◽  
The Body ◽  
The Other ◽  
The Subject ◽  
State Of Activity

The correlation between the mammary glands and the other organs concerned in generation presents perhaps the most striking example of the interdependence of the growth and activities of different organs of the body. Although the manner in which this correlation is brought about has been the subject of speculation for many years, especially among medical men, it is only quite recently that any attempt has been made to apply experimental methods to its explanation. In the case of the mammary glands we have organs which are present in both sexes, and at birth are in the same immature condition. In both sexes there is frequently, during the few days after birth, an enlargement of the glands and an actual secretion of fluid, which is known as “witch’s milk.” This state of activity disappears at the end of the first or second week, and till puberty the glands remain in the same undeveloped condition. At this period in Man the first difference appears between the mammary glands of the two sexes, a rapid growth taking place in the female, and accompanying the commencement of the ovarian functions.

High Heels sebagai Agensi bagi Tubuh Wanita

2020 ◽  
Vol 5 (2) ◽  
pp. 196
Author(s):  
Sunandar Macpal ◽  
Fathianabilla Azhar
Keyword(s):  
Body Image ◽  
Literature Review ◽  
The Body ◽  
The Other ◽  
Body Image Disturbance ◽  
Other Hand ◽  
High Heels ◽  
Experience Pain ◽  
Woman's Body

The aims of this paper is to explain the use of high heels as an agency for a woman's body. Agency context refers to pain in the body but pain is perceived as something positive. In this paper, the method used is a literature review by reviewing writings related to the use of high heels. The findings in this paper that women experience body image disturbance or anxiety because they feel themselves are not beautiful or not attractive. The use of high heels, makes women more attractive and more confident, on the other hand the use of high heels actually makes women feel pain and discomfort. However, for the achievement of beauty standards, women voluntarily allow their bodies to experience pain. However, the agency's willingness to beauty standards here is meaningless without filtering and directly accepted. Instead women keep negotiating with themselves so as to make a decision why use high heels.

EXPRESSION OF SOME IMMUNOLOGIC MARKERS FOR THE DIAGNOSIS OF SUSPECTED LYMPHOID LESIONS OF LYMPHOMA

2018 ◽  
Vol 8 (4) ◽  
pp. 28-33
Author(s):  
Mao Nguyen Van ◽  
Thao Le Thi Thu
Keyword(s):  
Correct Diagnosis ◽  
Tumour Cells ◽  
The Body ◽  
The Other ◽  
Cervical Region ◽  
Cross Sectional ◽  
Immunologic Markers ◽  
Microscopic Features ◽  
Poor Differentiation ◽  
Benign Tumours

Background: In practice it was difficult or impossible to have a correct diagnosis for the lymphoid proliferation lesions based on only H.E standard histopathology. In addition to histopathology, the application of immunohistochemistry was indispensable for the definitive diagnosis of the malignant or benign tumours and the origin of the tumour cells as well. Objectives: 1. To describe the gross and microscopic features of the suspected lesions of lymphoma; 2. To asses the expression of some immunologic markers for the diagnosis and classification of the suspected lesions of lymphoma. Materials and Method: Cross-sectional research on 81 patients diagnosed by histopathology as lymphomas or suspected lesions of lymphoma, following with immunohistopathology staining of 6 main markers including LCA, CD3, CD20, Bcl2, CD30 and AE1/3. Results: The most site was lymph node 58.1% which appeared at cervical region 72.3%, then the stomach 14.9% and small intestine 12.4%. The other sites in the body were met with lower frequency. Histopathologically, the most type of the lesions was atypical hyperplasia of the lymphoid tissue suspecting the lymphomas 49.4%, lymphomas 34.5%, the other diagnoses were lower including inflammation, poor differentiation carcinoam not excluding the lymphomas, lymphomas differentiating with poor differentiation carcinomas. Immunohistochemistry showed that, LCA, CD3, CD20, Bcl2, CD30 and AE1/3 were all positive depending on such type of tumours. The real lymphomas were 48/81 cases (59.3%), benign ones 35.8% and poor differentiated carcinomas 4.9%. Conclusion: Immunohistochemistry with 6 markers could help to diagnose correctly as benign or malignant lesions, classify and determine the origin of the tumour cells as lymphocytes or epithelial cells diagnosed by histopathology as lymphomas or suspected lesions of lymphomas. Key words: histopathology, immunohistochemistry, lymphomas, poor differentiated carcinomas, hyperplasia, atypicality

Basic Concepts and Definitions of Allergology

2019 ◽  
Author(s):  
Zoran Vrucinic
Keyword(s):  
Immune Reaction ◽  
The Body ◽  
The Other ◽  
Specific Response ◽  
Other Hand ◽  
Medical Vocabulary ◽  
The Future ◽  
Basic Concepts ◽  
Basic Insight ◽  
Insight Into

The future of medicine belongs to immunology and alergology. I tried to not be too wide in description, but on the other hand to mention the most important concepts of alergology to make access to these diseases more understandable, logical and more useful for our patients, that without complex pathophysiology and mechanism of immune reaction,we gain some basic insight into immunological principles. The name allergy to medicine was introduced by Pirquet in 1906, and is of Greek origin (allos-other + ergon-act; different reaction), essentially representing the reaction of an organism to a substance that has already been in contact with it, and manifested as a specific response thatmanifests as either a heightened reaction, a hypersensitivity, or as a reduced reaction immunity. Synonyms for hypersensitivity are: altered reactivity, reaction, hypersensitivity. The word sensitization comes from the Latin (sensibilitas, atis, f.), which means sensibility,sensitivity, and has retained that meaning in medical vocabulary, while in immunology and allergology this term implies the creation of hypersensitivity to an antigen. Antigen comes from the Greek words, anti-anti + genos-genus, the opposite, anti-substance substance that causes the body to produce antibodies.

Body and Soul

2017 ◽  
Author(s):  
Isabella Image
Keyword(s):  
Human Person ◽  
Fourth Century ◽  
The Body ◽  
The Other ◽  
Spiritual Nature ◽  
Body And Soul ◽  
Century Thought

This chapter discusses Hilary’s dichotomous body–soul anthropology. Although past scholars have tried to categorize Hilary as ‘Platonic’ or ‘Stoic’, these categories do not fully summarize fourth-century thought, not least because two-way as well as three-way expressions of the human person are also found in Scripture. The influence of Origen is demonstrated with particular reference to the commentary on Ps. 118.73, informed by parallels in Ambrose and the Palestinian Catena. As a result, it is possible to ascribe differences between Hilary’s commentaries to the fact that one is more reliant on Origen than the other. Nevertheless, Hilary’s position always seems to be that the body and soul should be at harmony until the body takes on the spiritual nature of the soul.

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