Hypothesis of Early Development of Chicken Embryos

AbstractParaffin histology is one of the most important and commonly-used laboratory techniques in diagnostic histopathology. The discovery of paraffin embedding is often attributed to the pathologist Edwin Klebs. Klebs was following the lead of Stricker, who embedded embryos in a mixture of hot stearin and white beeswax. We show that Klebs experimented with paraffin wax for embedding tumour tissue. But he quickly rejected it as unsuitable because paraffin wax did not infiltrate the tissue. One of Klebs’ correspondents, embryologist Wilhelm His, Sr., learned of Klebs’ experiments and decided to try paraffin embedding. His dehydrated chicken embryos in alcohol, cleared them in lavender oil, and dripped hot paraffin wax onto them. This process allowed His to cut good sections. Here, we have replicated His’s paraffin embedding protocol in order to determine whether His had indeed made the landmark discovery of infiltration embedding with paraffin wax. We followed the protocol that he gives in his 1868 monograph on the early development of the chicken. The protocol described by His failed, in our hands, to yield sections of the quality that he illustrates in his monograph. Typically, the tissue disintegrated when sectioned due to poor infiltration of the wax. Usable sections could only be obtained if His’s protocol was modified by melting the embedded embryos in fresh paraffin wax. One explanation for our findings is that we failed to faithfully replicate His’s protocol. Another is that his protocol was incomplete. We suggest that His is likely to have discovered and perfected infiltration embedding with paraffin wax but did not publish a complete protocol.

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Mesodermal subdivision along the mediolateral axis in chicken controlled by different concentrations of BMP-4

Development ◽

10.1242/dev.124.10.1975 ◽

1997 ◽

Vol 124 (10) ◽

pp. 1975-1984 ◽

Cited By ~ 27

Author(s):

A. Tonegawa ◽

N. Funayama ◽

N. Ueno ◽

Y. Takahashi

Keyword(s):

Early Development ◽

Molecular Mechanisms ◽

Lateral Plate Mesoderm ◽

Tgf Beta ◽

Presomitic Mesoderm ◽

Lateral Plate ◽

Chicken Embryos ◽

Cos Cells ◽

Low Level ◽

High Level

Molecular mechanisms by which the mesoderm is subdivided along the mediolateral axis in early chicken embryos have been studied. When the presomitic mesoderm (medial mesoderm) was transplanted into the lateral plate, the graft was transformed into lateral plate tissue, indicating that the primitive somite was not fully committed and that the lateral plate has a cue for mesodermal lateralization. Since the lateral plate expresses a high level of BMP-4 mRNA, a member of the TGF-beta family, we hypothesized that it is the molecule responsible for the lateralization of the somite. To test this, we transplanted COS cells producing BMP-4 into the presomitic region. Those cells locally prevented the presomitic cells from differentiating into somites, converting them instead into lateral plate mesoderm, which was revealed by expression of cytokeratin mRNA, a marker for the lateral plate. The effect was dependent on the level of effective BMP-4: with a high level of BMP-4, the somite was transformed completely to lateral plate; with a low level, the somite formed but was occupied by the lateral somitic component expressing cSim 1, a marker for the lateral somite. These results suggest that different thresholds of effective BMP-4 determine distinct subtypes of the mesoderm as a lateralizer during early development.

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Accumulation of c-src mRNA is developmentally regulated in embryonic neural retina.

Molecular and Cellular Biology ◽

10.1128/mcb.6.11.4109 ◽

1986 ◽

Vol 6 (11) ◽

pp. 4109-4111 ◽

Cited By ~ 20

Author(s):

L Vardimon ◽

L E Fox ◽

A A Moscona

Keyword(s):

Cell Growth ◽

Early Development ◽

Neural Retina ◽

Histone Mrna ◽

Developmentally Regulated ◽

Adult Retina ◽

Chicken Embryos ◽

Low Level ◽

Early Increase ◽

Embryonic Life

Accumulation of c-src mRNA gradually increased during early development of the neural retina in chicken embryos and reached a peak by days 11 to 13 of embryonic life. Thereafter, its amount declined to a low level which persisted also in adult retina. The early increase in c-src mRNA correlated inversely with the decrease in the amount of H3.2 replication histone mRNA and with the decline in the rate of cell growth. The accumulation profile of c-src mRNA corresponded to that of pp60c-src protein, suggesting that the latter is regulated at the level of transcription.

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Accumulation of c-src mRNA is developmentally regulated in embryonic neural retina

Molecular and Cellular Biology ◽

10.1128/mcb.6.11.4109-4111.1986 ◽

1986 ◽

Vol 6 (11) ◽

pp. 4109-4111

Author(s):

L Vardimon ◽

L E Fox ◽

A A Moscona

Keyword(s):

Cell Growth ◽

Early Development ◽

Neural Retina ◽

Histone Mrna ◽

Developmentally Regulated ◽

Adult Retina ◽

Chicken Embryos ◽

Low Level ◽

Early Increase ◽

Embryonic Life

Accumulation of c-src mRNA gradually increased during early development of the neural retina in chicken embryos and reached a peak by days 11 to 13 of embryonic life. Thereafter, its amount declined to a low level which persisted also in adult retina. The early increase in c-src mRNA correlated inversely with the decrease in the amount of H3.2 replication histone mRNA and with the decline in the rate of cell growth. The accumulation profile of c-src mRNA corresponded to that of pp60c-src protein, suggesting that the latter is regulated at the level of transcription.

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Individual differences, social attention, and the history of the social motivation hypotheses of autism

Behavioral and Brain Sciences ◽

10.1017/s0140525x18002509 ◽

2019 ◽

Vol 42 ◽

Author(s):

Peter C. Mundy

Keyword(s):

Individual Differences ◽

Early Development ◽

Emotional Development ◽

Social Motivation ◽

Social Attention ◽

Social Emotional Development ◽

Social Emotional ◽

Precise Understanding ◽

The Social ◽

History Of

Abstract The stereotype of people with autism as unresponsive or uninterested in other people was prominent in the 1980s. However, this view of autism has steadily given way to recognition of important individual differences in the social-emotional development of affected people and a more precise understanding of the possible role social motivation has in their early development.

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Classical social reward signatures in infants with later ASD

Behavioral and Brain Sciences ◽

10.1017/s0140525x18002492 ◽

2019 ◽

Vol 42 ◽

Author(s):

Teodora Gliga ◽

Mayada Elsabbagh

Keyword(s):

Early Development ◽

Social Motivation ◽

Self Report ◽

Social Reward ◽

Socially Motivated

Abstract Autistic individuals can be socially motivated. We disagree with the idea that self-report is sufficient to understand their social drive. Instead, we underscore evidence for typical non-verbal signatures of social reward during the early development of autistic individuals. Instead of focusing on whether or not social motivation is typical, research should investigate the factors that modulate social drives.

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Early Development of Drug-Induced Hepatic Necrosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066942 ◽

1971 ◽

Vol 29 ◽

pp. 576-577

Author(s):

F. G. Zaki ◽

E. Detzi ◽

C. H. Keysser

Keyword(s):

Early Development ◽

Hepatic Necrosis ◽

Screening Tests ◽

Dense Matrix ◽

Sprague Dawley ◽

Electron Microscopic ◽

Drug Induced ◽

Hepatocellular Damage ◽

Sprague Dawley Rats ◽

Microscopic Studies

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.

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The early development of antenna and antennal sensilla in the noctuid moth, Agrotis segetum (Insecta: Lepidoptera)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160066 ◽

1990 ◽

Vol 48 (3) ◽

pp. 502-503

Author(s):

Eric Hallberg ◽

Lina Hansén

Keyword(s):

Cell Death ◽

Stem Cell ◽

Early Development ◽

Larval Stage ◽

Pupal Stage ◽

Agrotis Segetum ◽

Antennal Sensilla ◽

Noctuid Moth ◽

Standard Procedures

The antennal rudiments in lepidopterous insects are present as disks during the larval stage. The tubular double-walled antennal disk is present beneath the larval antenna, and its inner layer gives rise to the adult antenna during the pupal stage. The sensilla develop from a cluster of cells that are derived from one stem cell, which gives rise to both sensory and enveloping cells. During the morphogenesis of the sensillum these cells undergo major transformations, including cell death. In the moth Agrotis segetum the pupal stage lasts about 14 days (temperature, 25°C). The antennae, clearly seen from the exterior, were dissected and fixed according to standard procedures (3 % glutaraldehyde in 0.15 M cacaodylate buffer, followed by 1 % osmiumtetroxide in the same buffer). Pupae from day 1 to day 8, of both sexes were studied.

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Live Confocal Analysis of Fertilization and Early Development

Microscopy and Microanalysis ◽

10.1017/s1431927600031135 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 1012-1013

Author(s):

Uyen Tram ◽

William Sullivan

Keyword(s):

Drosophila Melanogaster ◽

Embryonic Development ◽

Real Time ◽

Early Development ◽

Fluorescent Probes ◽

Primary Defect ◽

Fluorescent Analysis ◽

Dynamic Event ◽

Enormous Amount ◽

Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

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