scholarly journals Changes in the ovary of the mouse following exposure to X-rays. Part II.—- Irradiation at or before birth

1927 ◽  
Vol 101 (707) ◽  
pp. 95-114 ◽  
Keyword(s):  
Major Part ◽  
Histological Study ◽  
Present Series ◽  
Germinal Epithelium ◽  
Corpora Lutea ◽  
X Rays ◽  
New Born ◽  
Series Of Experiments ◽  
Theca Interna ◽  
Almost All

The ovaries of a series of mice X-rayed at weaning-time (3 weeks old) were described in a previous paper (2), and the æstrous cycles of these animals were dealt with elsewhere (Parkes, 4). Although all the ovaries of the animals described in the latter paper were devoid of follicles and the majority of corpora lutea, normal æstrous cycles were observed in almost all cases. Histological study led us to conclude that following irradiation:— (1) All the oocytes degenerated completely, and the cells of the membrana granulosa, and of the theca interna, in follicles where it was differentiated, followed their example shortly afterwards. In a few cases the larger follicles did not degenerate after the disappearance of the oocyte but formed corpora lutea atretica which persisted but had no effect on the cycle. (2) The germinal epithelium proliferated cords of cells, which pressed the remnants of the old stroma into the medullary region. These cords formed the major part of the irradiated gonad and were probably responsible for the production of the oestrus-producing hormone “oestrin.” (3) The germinal epithelium in some cases proliferated a second lot of cords, which resembled structures described by some authors as anovular follicles. They resembled more closely, however, the “ tubules ” of some free-martin testes and structures described in the rabbit ovary as “spermatic tubules” (Hammond, 3). These cords were shown to have no influence on the oestrous cycle. The present series of experiments were carried out on animals of a different age, with a view to corroborating, if possible, these results from a different standpoint. It was hoped that the follicles might be removed more completely and satisfactorily, and that the formation of corpora lutea atretica might be avoided by irradiation at or before birth, as follicles are scarcely formed in the ovary of the mouse at this time. This expectation was unfortunately not realised. Further, it was thought that the more actively growing gonad of the fætal or new-born mouse might exhibit more extreme changes than those of the 3 weeks old mouse. Finally, since the accessory organs of reproduction are so little differentiated until some time after birth it was to be expected that the effect of the irradiated gonad on them would be more easily demonstrated.

scholarly journals Changes in the ovary of the mouse following exposure to X-rays.—Part III. Irradiation of the non-parous adult

1927 ◽  
Vol 101 (710) ◽  
pp. 316-328 ◽  
Keyword(s):  
Histological Study ◽  
Corpora Lutea ◽  
X Rays ◽  
Theca Interna ◽  
Almost All

The ovaries of a series of mice X-rayed at weaning time (3 weeks old) were described in the first part (1) of this series of papers, and of a series X-rayed at or before birth in the second part (2). The œstrous cycles of these animals were dealt with elsewhere (Parkes (4, 5)). In almost all animals normal cestrous cycles were maintained, although the ovaries were devoid of follicles and, in most cases, of corpora lutea. Histological study led us to conclude that following irradiation:— (1) All the oocytes degenerated completely, and that the cells of the membrana granulosa, and of the theca interna, in follicles where it was differentiated, subsequently followed their example. In some cases the follicles did not degenerate, but grew and formed corpora lutea atretica. These persisted but had no effect on the cycle.

XI.—The Effects of Implantation upon Ovarian Grafts in the Male Mouse

1928 ◽  
Vol 47 ◽  
pp. 148-164
Author(s):  
Y. Tamura
Keyword(s):  
Male Mouse ◽  
Germinal Epithelium ◽  
Interstitial Tissue ◽  
Corpora Lutea ◽  
Male Mice ◽  
Follicular Cells ◽  
Ovarian Structure ◽  
Series Of Experiments ◽  
Ovarian Graft ◽  
Time Of Operation

SummaryI. A series of experiments is described in which ovaries from litter sisters at the age of from 8 to 20 weeks old were grafted on to the surface of the kidney of male mice.II. The grafts were examined at periods varying from 10 to 35 days after operation. It was found that in the majority of cases the graft had retained the typical ovarian structure; in one case corpora lutea were present (35 days after transplantation).III. It is suggested that the survival of the graft is dependent primarily upon its vascularisation, and secondarily upon the degree of activity of the germinal epithelium.IV. It is assumed that if the germinal epithelium is unimpaired it proliferates; proliferation occurs first sometime before the 10th day, and continues until the graft has attained the stage at which it was at the time of operation.V. The original large follicles begin to degenerate soon after transplantation; the medium-sized and small ones develop for a certain period of time, but afterwards also undergo degeneration.VI. Graafian follicles undergo degeneration at various stages of development.VII. Interstitial tissue appears to be derived from the follicular cells of the atretic, or more probably of the primary and medium-sized anovular follicles.VIII. It is concluded that the presence of the testis does not affect the vitality of the ovarian graft.

scholarly journals On the occurrence of the œstrous cycle after X-ray sterilisation. Part III.— The periodicity of œstrus after sterilisation of the adult

1927 ◽  
Vol 101 (711) ◽  
pp. 421-449 ◽  
Keyword(s):  
Female Mouse ◽  
Young Animal ◽  
Young Female ◽  
Oestrous Cycle ◽  
Germinal Epithelium ◽  
Corpora Lutea ◽  
X Rays ◽  
X Ray ◽  
Post Irradiation ◽  
Cyclic Phenomena

In Parts I and II (2, 3, 10, 11) of these series it has been shown that the destruction of the Graafian follicles in the young female mouse by exposure to X-rays does not inhibit the appearance of œstrous symptoms when the animals subsequently become mature. The conclusions arrived at were briefly as follows :— ( a ) After irradiation of the young animal the follicles disintegrate and are re-absorbed, this process being accompanied in its later stages by the proliferation of new tissue from the germinal epithelium. ( b ) When the animal becomes adult the ovary contains neither organised follicles nor corpora lutea vera, and consists largely of post-irradiation proliferation of the germinal epithelium. In spite of this, however, the cyclic phenomena of œstrus still appear.

scholarly journals Changes in the ovary of the mouse following exposure to X-rays. Part I.—Irradiation at three weeks old

1927 ◽  
Vol 101 (706) ◽  
pp. 29-56 ◽  
Keyword(s):  
Point Of View ◽  
Oestrous Cycle ◽  
Follicular Epithelium ◽  
Considerable Importance ◽  
Corpora Lutea ◽  
X Rays ◽  
Histological Changes ◽  
Post Irradiation ◽  
Theca Interna

In a recent paper (Parkes, 8) the effect on the œstrous cycle of destruction of the Graafian follicles at three weeks old by X-rays was described, and the conclusion was reached that the absence of follicles does not inhibit the appearance of the œstrous cycle when the female subsequently becomes mature. In this earlier paper, however, the histological effects in the ovary after exposure to X-rays were only dealt with very briefly, and it is the object of this present paper to consider in detail the histological changes following irradiation at weaning time. The histological effects of irradiation at birth and of irradiation of the adult, together with the effects on the oestrous cycle, will be dealt with in subsequent communications. Two main problems are presented by the histology of these irradiated ovaries. In the first place, the exact fate of the disintegrating follicle is of considerable importance. The maturation of follicles has long been considered to be essential for the appearance of oestrus, and evidence has recently been adduced to show that the hormone responsible for oestrus is elaborated by the follicle. Various elements of the follicle have been held to be responsible by various authors. Allen and Doisv (1), for instance, suggest the follicular epithelium, while Zondek and Aschheim (16) maintain that the theca interna is concerned. Since, therefore, the irradiated ovaries are capable of elaborating oestrin it is essential to know whether the disappearance of follicular tissue is complete or only partial. As reported previously, it is possible to say with certainty that ovum and follicular epithelium disappearentirely, except where the latter helps to form corpora lutea atretica, but the fate of the theca interna is less obvious. This latter question is, however, of importance from a physiological point of view. The second main problem connected with these ovaries is the nature of the cords of the second post-irradiation proliferation which ultimately arise in most of the ovaries after irradiation, and which were tentatively suggested in the earlier paper to be of spermatic character.

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

scholarly journals THE MECHANISM OF CHANGE IN RESISTANCE OF ERYTHROCYTES TO HYPOTONIC SALT SOLUTIONS

1925 ◽  
Vol 7 (5) ◽  
pp. 587-598 ◽  
Author(s):  
S. C. Brooks
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Present Series ◽  
Salt Solutions ◽  
Great Uncertainty ◽  
Hypotonic Hemolysis ◽  
Series Of Experiments

Ashby's work on the effects of KCl and NaCl on the resistance to hypotonic hemolysis of K•-rich and K•-poor erythrocytes has been repeated with great attention to purity of materials and refinement of technique. The results fail to agree with those of Ashby. 1. KCl produces greater loss in resistance to hypotonic hemolysis than does NaCl, irrespective of the species of the animal from which the cells are taken. 2. While cases of an increase in resistance have been encountered in my experiments, they are either very slight, or else the particular determination is subject to very great uncertainty. The great increases in resistance found by Ashby are not even approached in any of the present series of experiments. 3. Ashby's generalization that KCl and NaCl have opposite effects on red blood cells, and that the sense of these effects depends on whether the cell is K•-rich or K•-poor is not substantiated.

The role of ultimobranchial bodies in the modulation of the response of chick embryos to 1,25-dihydroxycholecalciferol

Development ◽  
1986 ◽  
Vol 97 (1) ◽  
pp. 87-94
Author(s):  
Roberto Narbaitz ◽  
Jaffar Soleimani Rad
Keyword(s):  
Bone Resorption ◽  
Ethyl Alcohol ◽  
Inorganic Phosphate ◽  
Histological Study ◽  
Chorioallantoic Membrane ◽  
Chick Embryos ◽  
Series Of Experiments ◽  
Ultrastructural Characteristics ◽  
Bone Trabeculae

Ultimobranchial bodies (UBBs) were dissected from 17-day-old chick embryos and grafted onto the chorioallantoic membrane of 8-day-old embryos. The embryos with UBB grafts as well as sham-grafted controls were injected on the 10th day of incubation with 100 ng 1,25(OH)2D3 dissolved in ethyl alcohol or with an equal volume of ethyl alcohol alone; embryos were sacrificed on the 13th day. Grafted UBBs showed ultrastructural characteristics typical of actively secreting glands. A histological study of the tibiae from all embryos showed that while the grafted embryos responded to the injection of 1,25(OH)2D3 with a peripheral rim of undermineralized bone trabeculae, sham-grafted embryos never did so. These results confirm the original hypothesis that the presence of differentiated UBBs is a precondition for the production of undermineralized bone (osteoid) by 1,25(OH)2D3. In a second series of experiments, similarly treated embryos were sacrificed on the 10th, 11th, 12th and 13th day; the levels of calcium and inorganic phosphate were determined in their blood. The injection of 1,25(OH)2D3 produced in all embryos hypercalcaemia and hypophosphataemia. However, the hypophosphataemic response was more prolonged in the embryos with UBB grafts than in sham-grafted ones. These results suggest that the grafted UBBs prolonged the hypophosphataemic response, probably by secreting calcitonin and thus reducing the rate of bone resorption. It is also probable that the prolonged hypophosphataemia produced or contributed to the undermineralization of the peripheral (subperiosteal) trabeculae.

1. Experiments on the Colorific Properties of Lichens

1872 ◽  
Vol 7 ◽  
pp. 43-44
Author(s):  
W. Lauder Lindsay
Keyword(s):  
Present Series ◽  
Botanical Society ◽  
Chemical Reagents ◽  
Series Of Experiments ◽  
Positive Results

The author's paper consists mainly of a Table exhibiting certain of the positive results of many hundred experiments on the colouring matters contained in or educible from Lichens. The experiments in question are partly a repetition, and partly an extension on a more systematic and complete scale, of a series of researches made by the author between 1852 and 1855, the results of which were originally submitted to the Botanical Society of Edinburgh. The present series of experiments includes the whole family of the Lichens. The Table represents mainly the effects of chemical reagents on solutions of the lichen colouring-matters, or colorific principles, in boiling alcohol or water. The nomenclature of the Colour-reactions is that of Werner and Syme.

scholarly journals Massive star mass-loss revealed by X-ray observations of young supernovae

2018 ◽  
Vol 14 (S346) ◽  
pp. 83-87
Author(s):  
Vikram V. Dwarkadas
Keyword(s):  
Mass Loss ◽  
Massive Stars ◽  
Ambient Medium ◽  
Mass Loss Rate ◽  
Stellar Mass ◽  
X Rays ◽  
X Ray ◽  
The Common ◽  
Almost All ◽  
Loss Rates

AbstractMassive stars lose a considerable amount of mass during their lifetime. When the star explodes as a supernova (SN), the resulting shock wave expands in the medium created by the stellar mass-loss. Thermal X-ray emission from the SN depends on the square of the density of the ambient medium, which in turn depends on the mass-loss rate (and velocity) of the progenitor wind. The emission can therefore be used to probe the stellar mass-loss in the decades or centuries before the star’s death.We have aggregated together data available in the literature, or analysed by us, to compute the X-ray lightcurves of almost all young supernovae detectable in X-rays. We use this database to explore the mass-loss rates of massive stars that collapse to form supernovae. Mass-loss rates are lowest for the common Type IIP supernovae, but increase by several orders of magnitude for the highest luminosity X-ray SNe.

A Report of a Histological Study of the Eyes and Gonads of Mice Treated with a Light Dosage of X-Rays

1924 ◽  
Vol 58 (657) ◽  
pp. 383-384
Author(s):  
L. H. Snyder ◽  
Margaret Schneider ◽  
C. C. Little
Keyword(s):  
Histological Study ◽  
X Rays
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