Gastrulation in the mouse: assessment of cell populations in the epiblast of twl8/tw18 embryos

Development ◽  
1978 ◽  
Vol 47 (1) ◽  
pp. 39-52
Author(s):  
M. H. L. Snow ◽  
D. Bennett
Keyword(s):  
Mitotic Activity ◽  
Primitive Streak ◽  
Small Region ◽  
Cell Number ◽  
Proliferative Zone ◽  
Mitotic Abnormalities ◽  
Number Increase ◽  
High Mitotic Activity ◽  
Very High ◽  
Mitotic Disturbances

Homozygous tW18 embryos die prior to organogenesis. They develop gross abnormalities shortly after primitive streak formation. Anatomically, the lesion appears to be confined to the mesoderm with that tissue showing ultrastructural deficiencies and abnormal migration (Spiegelman & Bennett, 1974), and failing to develop in teratomas produced from mutant embryos (Artzt & Bennett, 1972). Analysis of growth rate by determining cell number increase, and by mapping mitotic activity and planes of cleavage in the epiblast shows that the mutant embryos are small but paradoxically show overall a very high mitotic activity, approximately double that of their normal litter mates. They also show a marked disorientationof the planes of cleavage in most of the epiblast. In pre-primitive streak embryos, before gross abnormality is detectable, two types of embryo can be found. One group constitutes the small embryos which also show the mitotic disturbances characteristic of the later stage mutants. The second group, larger embryos, do not show mitotic abnormalities. The tW18 allele thus seems to act several hours before primitive streak formation. Since there is no difference in the amount of cell death between mutant and normal embryos until 6·75 days p.c. it seems that arrest in division is the cause of the elevated mitotic index in mutants. Significantly a small region of the epiblast in mutant embryos is free of the mitotic abnormalities characteristic of the tissue as a whole. This region is the so-called proliferative zone (Snow, 1977) and the data suggest that it may be from this region that some of the ectoderm of the later embryos is produced.

scholarly journals Gastrulation in the mouse: Growth and regionalization of the epiblast

Development ◽  
1977 ◽  
Vol 42 (1) ◽  
pp. 293-303 ◽  
Author(s):  
M. H. L. Snow
Keyword(s):  
Mouse Embryo ◽  
Rapid Growth ◽  
Generation Time ◽  
Primitive Streak ◽  
Small Region ◽  
Cell Generation ◽  
Cell Numbers ◽  
Proliferative Zone ◽  
The Mean

Histological determination of cell numbers in the mouse embryo between 4½ and 7½ days post coitum show that growth during this period, in which gastrulation occurs, is not uniform. Prior to primitive streak formation mean cell generation time is about 9 h. Co-incidental with the appearance of the primitive streak the embryo enters a period of rapid growth, lasting about 24 h, during which the mean cell generation time must be about 5 h in order to account for the increase in cell numbers. A more detailed study, in which variations in mitotic activity in different regions of the embryo have been analysed, has identified a small region, the so-called ‘proliferative zone’, constituting about 10% of the whole epiblast, in which cell generation time may average as little as 2–3 h over a 24 h period. The cell generation time for other epiblast regions is estimated at about 6·5 h. It is calculated that the proliferative zone, in the 24 h period commencing with primitive streak formation, could generate about half the cells in the 7½-day embryo. The topographical consequences of such a rapidly expanding region in the embryo are discussed in the light of other, circumstantial evidence, and it is postulated that the cells generated in the PZ may constitute the ectoderm of later stage embryos.

Solitary Fibrous Tumor of the Prostate

2001 ◽  
Vol 125 (2) ◽  
pp. 274-277
Author(s):  
Michael R. Pins ◽  
Steven C. Campbell ◽  
William B. Laskin ◽  
Karen Steinbronn ◽  
Daniel P. Dalton
Keyword(s):  
Mitotic Activity ◽  
Solitary Fibrous Tumor ◽  
Growth Pattern ◽  
Spindle Cell ◽  
Cytologic Atypia ◽  
Diffuse Growth ◽  
High Mitotic Activity ◽  
Spindle Cell Tumors ◽  
Fibrous Tumor

Abstract We report 2 cases of solitary fibrous tumor of the prostate. Histologically, both tumors demonstrated a multipatterned architecture with varying degrees of collagenization and hemangiopericytoma-like foci, and both were composed of CD34-immunopositive spindled cells that insinuated themselves between strips of collagen. The tumor in case 1 was well circumscribed and showed minimal mitotic activity or pleomorphism, whereas the tumor in case 2 was more cellular, less collagenous, had a more diffuse growth pattern, and exhibited cytologic atypia and high mitotic activity. Prostatic solitary fibrous tumor must be distinguished from other spindle cell tumors reported to occur in the prostate. To our knowledge, these cases represent only the fifth and sixth reported cases of prostatic solitary fibrous tumor.

Improving Biomaterials from a Cellular Point of View

2006 ◽  
Vol 925 ◽  
Author(s):  
Venu Gopal Varanasi ◽  
T. Vallortigara ◽  
P. M. Loomer ◽  
E. Saiz ◽  
A. P. Tomsia ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Cell Number ◽  
Point Of View ◽  
Dissolution Behavior ◽  
Ti Alloy ◽  
Bioactive Glasses ◽  
Culture Studies ◽  
Cell Numbers ◽  
Number Increase

ABSTRACTBioactive glasses (6P55) used for coating Ti/Ti-alloy were tested for their in vitro behavior in a comparative study with commercial Bioglass™ (45S5) and commercial Ti alloy (Ti6Al4V). In vitro testing included pH and dissolution rate determination in simulated body fluid (SBF) along with in vitro cyto compatibility testing. It was seen in this work that 6P55 and 45S5 had similar dissolution behavior, demonstrating t½ dependence and maximum pH of approximately 8.1 after 10 days of immersion. This pH was reduce by 0.2 0.4 pH units when the in vitro V:A ratio was increased from 1 to 3. The dissolution rate of these glasses approached 0 after additional immersion tests after 15 days and the pH stablilized at less than 7.5. Cell culture studies showed that both glasses behaved in similar fashion after 16 hours in culture. Both glasses had an increase in cell numbers of close to 200-250%, whereas Ti6Al4V had a less pronounced cell number increase (∼ 180%)

Experiments on Neuromery in Ambystoma punctatum Embryos

Development ◽  
1956 ◽  
Vol 4 (1) ◽  
pp. 66-72
Author(s):  
Bengt Källén
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Mitotic Activity ◽  
Present Author ◽  
Similar Nature ◽  
High Mitotic Activity ◽  
The Central Nervous System ◽  
Further Development ◽  
The Brain ◽  
Low Activity

In a series of papers the present author has discussed the nature and significance of the transverse bulges of the central nervous system of vertebrates, long since known as neuromeres. Their formation and further development have been described and it has been shown that they are signs of a proliferation pattern, made up of transverse bands of high mitotic activity alternating with bands of low activity. It has also been demonstrated that the neuromeric pattern is preceded by another pattern of a similar nature, mirrored in the formation of the so-called proneuromeres, and is followed by a third pattern, giving rise to the postneuromeres or transverse bands of migration areas. For further details of these investigations, the reader is referred to Bergquist & Källén (1954). An unsolved question is the nature of the factors that cause the patterning of the mitoses and therefore also the bulging of the brain wall to form neuromeres.

4.20 T+ cell number increase in the spleen of chicken embryos in GVH-R serial transfer experiments

1989 ◽  
Vol 13 (4) ◽  
pp. 392
Author(s):  
B. Fedecka-Bruner ◽  
J. Desveaux-Chabrol ◽  
F. Dieterlen-Liévre
Keyword(s):  
T Cell ◽  
Cell Number ◽  
Serial Transfer ◽  
Chicken Embryos ◽  
Number Increase

Diet-induced adipocyte number increase in adult rats: a new model of obesity.

1978 ◽  
Vol 235 (3) ◽  
pp. E279 ◽  
Author(s):  
I M Faust ◽  
P R Johnson ◽  
J S Stern ◽  
J Hirsch
Keyword(s):  
Adipose Tissue ◽  
Weight Gain ◽  
Cell Number ◽  
Chow Diet ◽  
Adipocyte Size ◽  
Adult Rats ◽  
Tissue Morphology ◽  
Number Increase ◽  
Dietary Obesity ◽  
Morphology Changes

Adult rats of various strains became obese when they were fed a highly palatable diet for several months. Analysis of their adipose tissue morphology revealed increases in both adipocyte size and number in most depots. Reintroduction of an ordinary chow diet to such animals precipitated a period of weight loss during which only mean adipocyte size returned to normal. Adipocyte number remained at the elevated level achieved during the period of weight gain. Thus, transient dietary obesity in rats results in a persistent obesity of a purely hyperplastic, nonhypertrophic form. Furthermore, the persistence of the cell number increase suggests that it is the result of proliferation or differentiation rather than of only an increase in the lipid content of a pool of very small and normally undetected adipocytes. An analysis of adipose tissue morphology changes during the course of diet-induced weight gain suggests that the achievement of some specific mean adipocyte size triggers the events that culminate in adipocyte number increase. What mechanisms may link adipocyte size to the formation of new adipocytes remains unknown.

A Rare Presentation of Paraovarian Sclerosing Stromal Tumor with High Mitotic Activity

2016 ◽  
Vol 29 (1) ◽  
pp. e13-e15 ◽  
Author(s):  
Sule Yesil ◽  
Hikmet Gulsah Tanyildiz ◽  
Nalan Akyurek ◽  
Ceyhun Bozkurt ◽  
Gurses Sahin
Keyword(s):  
Mitotic Activity ◽  
Stromal Tumor ◽  
Rare Presentation ◽  
High Mitotic Activity ◽  
Sclerosing Stromal Tumor

Oxyphilic Follicular Tumor Arising in Struma Ovarii

1994 ◽  
Vol 80 (6) ◽  
pp. 482-484 ◽  
Author(s):  
Simonetta Piana ◽  
Stefania Damiani ◽  
Donatella Santini
Keyword(s):  
Mitotic Activity ◽  
Aggressive Behaviour ◽  
Vascular Invasion ◽  
Present Report ◽  
Thyroid Tumor ◽  
Struma Ovarii ◽  
Nuclear Pleomorphism ◽  
High Mitotic Activity ◽  
Proliferative Lesion ◽  
Follicular Tumor

The present report describes a case of a proliferative lesion developed in a struma ovarii of a 26-year-old woman who presented with asymptomatic bilateral mature ovarian teratomas. The tumor immunohistochemically and ultrastructurally proved to be an oxyphilic follicular thyroid tumor. Although it showed some histologic features which could raise a suspicion of malignancy (solid, trabecular pattern and nuclear pleomorphism), no unequivocable signs of aggressive behaviour (high mitotic activity and vascular invasion) were evident. The patient was alive and well 1 year after a bilateral subtotal ovariectomy.

Differential mitosis and degeneration patterns in relation to the alterations in the shape of the embryonic ectoderm of early post-implantation mouse embryos

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 33-51
Author(s):  
R. E. Poelmann
Keyword(s):  
Cell Cycle ◽  
Cell Kinetics ◽  
Tritiated Thymidine ◽  
Primitive Streak ◽  
Cell Number ◽  
Mouse Embryos ◽  
Surface Ectoderm ◽  
Dividing Cells ◽  
Post Implantation ◽  
Embryonic Ectoderm

The shape of the embryonic ectoderm of early post-implantation mouse embryos changes greatly in the period of 6·2–7·3 days post coitum. The subcellular morphology of the embryonic ectoderm remains unchanged, except in the primitive-streak region. Cell kinetics differ between ectodermal regions. These differences may be related to the changes in the shape of the ectoderm. The increase in cell number in the lateral ectoderm (the prospective surface ectoderm) exceeds that in the frontal ectoderm (the future neurectoderm). This is not due to differences in the duration of the cell cycle. It can be explained, however, by the occurrence of different relative numbers of dividing and non-dividing cells. These numbers vary between the two regions. The percentage of non-dividing cells in the frontal ectoderm may reach 45, whereas in the lateral ectoderm this percentage is not higher than 15. Autoradiography in tritiated thymidine-treated embryos combined with the mitotic indices gave us all of the parameters necessary to present a model capable of clarifying the growth of the ectoderm during gastrulation, as well as the changes in the shape of the ectoderm.

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