THE FUNCTIONAL CAPACITY OF OVARIAN TISSUE TRANSPLANTED TO THE SPLEEN OR KIDNEY IN THE FERRET

1969 ◽  
Vol 45 (1) ◽  
pp. 91-97 ◽  
Author(s):  
B. T. DONOVAN

SUMMARY Ovarian tissue was autografted to the spleen or kidney of spayed anoestrous or oestrous ferrets to see whether inactivation of ovarian hormones occurred in the liver and to examine the feedback action of gonadal hormones on gonadotrophin secretion. Although the grafts survived in both sites as did homografts made in anoestrous females, the secretion of gonadal hormones was sufficient to cause oestrus only in a minority of animals and there was little difference in the function of grafts made to the spleen or kidney. Vulval swelling and uterine growth were caused by pellets of oestradiol inserted into the spleen so that it appears that this steroid can pass through the liver without loss of oestrogenic activity. It is concluded that little inactivation of gonadal steroids by the liver of the ferret takes place.

1972 ◽  
Vol 55 (3) ◽  
pp. 599-607 ◽  
Author(s):  
B. T. DONOVAN ◽  
A. N. LOCKHART

SUMMARY The release of ovulating hormone after acute treatment with gonadal steroids, or corpus luteum removal on different days of the oestrous cycle, was studied in the guinea-pig. Injection of 25, 50 or 100 μg oestradiol or 2·5 mg progesterone on day 13 of the cycle had no effect upon gonadotrophin secretion as judged by follicular histology, but markedly altered the sizes of the corpora lutea of the previous ovulation. Treatment with oestradiol on day 14 did not elicit gonadotrophin secretion. However, administration of the same hormones to animals given 10 μg oestradiol benzoate 24 h earlier caused ovulation or follicular luteinization. Progesterone (2·5 mg) appeared least effective in stimulating gonadotrophin release; 25 μg oestradiol were more effective when given at 12.00 h than at 24.00 h but treatment with both hormones caused ovulation when given at either time of day. Luteal volumes were not affected. Removal of corpora lutea during the second half of the cycle advanced the time of expected ovulation to day 15 or earlier when the procedure was carried out on days 8 or 9, but not on days 10–13. It is concluded that 4–5 days must elapse between the fall in plasma progesterone level associated with corpus luteum regression and the release of ovulating hormone.


1966 ◽  
Vol 34 (4) ◽  
pp. 469-478 ◽  
Author(s):  
B. T. DONOVAN ◽  
MARY C. O'KEEFFE

SUMMARY (1) The structure and function of ovarian autotransplants made to the spleen and kidney were compared in order to measure the ability of the liver to inactivate ovarian hormones at different ages in the rat. (2) In the immature rat the data from the uterine weights indicated that little or no hepatic inactivation of gonadal hormone occurred since grafts to the spleen or kidney were equally capable of maintaining normal uterine growth. (3) With increasing age, the liver appeared to develop the ability to inactivate ovarian hormones; this capacity was reflected by the difference in the uterine weights of animals bearing ovarian tissue in the kidney as opposed to those in the spleen. (4) The ability of the liver to metabolize ovarian hormones appeared to develop to a significant degree at about the time of puberty.


1973 ◽  
Vol 12 (2) ◽  
pp. 181-188
Author(s):  
Rafiq Ahmad

Like nations and civilizations, sciences also pass through period of crises when established theories are overthrown by the unpredictable behaviour of events. Economics is passing through such a crisis. The challenge thrown by the Great Depression of early 1930s took a decade before Keynes re-established the supremacy of economics. But this supremacy has again been upset by the crisis of poverty in the vast under-developed world which attained political independence after the Second World War. Poverty had always existed but never before had it been of such concern to economists as during the past twenty five years or so. Economic literature dealing with this problem has piled up but so have the agonies of poverty. No plausible and well-integrated theory of economic development or under-development has emerged so far, though brilliant advances have been made in isolated directions.


2018 ◽  
Vol 7 (3) ◽  
pp. 452-493
Author(s):  
Daniel Morales Ruvalcaba

El hegemón es un actor fundamental en la gobernanza internacional. No obstante, mientras que el comercio, poder y guerra han sido temas ampliamente abordados desde los estudios sobre hegemonía en las Relaciones Internacionales, se ha avanzado poco en análisis de las ideas que orientan el comportamiento del hegemón. La hipótesis aquí planteada es que las hegemonías recorren a lo largo de su existencia cinco fases (emergencia, despliegue, apogeo, declive y extinción) y, durante cada una de ellas, el Estado hegemónico asume ideologías específicas que orientan su comportamiento internacional, lo cual se traduce en la promoción de ciertas políticas internacionales, así como de alianzas y organizaciones internacionales con vocaciones específicas. Sin embargo, en la medida que evoluciona su poder nacional y el hegemón transita de una fase a otra, éste tiende a cambiar ideológicamente, abandonando ideas previas y asumiendo otras nuevas. Si bien dicha transición ideológica es pragmática -en función de las necesidades de su poder nacional- este cambio resulta discordante y criticable por otros actores del sistema. Este documento se compone de dos grandes partes: en la primera se establecen las cinco fases de un ciclo hegemónico y, luego, se exponen las ideologías que orientan el comportamiento del Estado hegemónico en ellas; la segunda parte se orienta a comprobar empíricamente las transiciones ideológicas durante las hegemonías neerlandesa, británica y estadounidense.   Abstract: The hegemon is a fundamental actor in international governance. However, while trade, power and war have been topics widely discussed from studies on hegemony in International Relations, little progress has been made in analyzing the ideas that guide the behavior of the hegemon. The hypothesis proposed here is that the hegemonies pass through five phases during their existence (emergence, deployment, apogee, decline and extinction) and, during each of them, the hegemonic State assumes specific ideologies that guide its international behavior. However, as the national power evolves, and the hegemon moves from one phase to another, it tends to change ideologically, abandoning previous ideas and assuming new ones. Although this ideological transition is pragmatic - depending on the power needs of the hegemon- this change results discordant and is criticized by other actors in the system. To demonstrate this, the following document is composed of two major parts: the first presents the five phases of a hegemonic cycle and, along with it, the ideologies that guide the behavior of the hegemonic State; the second part aims to empirically verify the ideological transitions during the hegemonies that have existed: the Dutch, the British and the American. Keywords: Hegemony, hegemonic political cycles, ideology, national power, hegemonic interregnum.     Recebido em: Agosto/2018. Aprovado em: Dezembro/2018.       


1982 ◽  
Vol 92 (1) ◽  
pp. 73-83 ◽  
Author(s):  
H. F. URBANSKI ◽  
B. K. FOLLETT

Male Japanese quail were castrated when sexually immature and immediately exposed to one of the following stimulatory lighting regimes for 52 days: 11 h light: 13 h darkness/day (11L : 13D), 12L : 12D, 13L : 11D, 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D or 23L : 1D. One group was retained on short days (8L : 16D). Clearcut differences in the plasma levels of LH and FSH emerged between the various groups. Levels remained very low in castrated quail on 8L : 16D but were much greater in those on 14L : 10D, 15L : 9D, 16L : 8D, 20L : 4D and 23L : 1D, eventually becoming 15 to 20 times higher. Less pronounced castration responses developed on 13L : 11D, 12L : 12D or 11L : 13D. Alterations in photoperiod after day 52 caused an appropriate rise or fall in LH secretion. Photoperiodically induced suppressions were rapid, being highly significant within 4 days, but increases usually had a slower time course. When sexually mature quail (on 16L : 8D) were castrated and transferred to 8L : 16D they also exhibited a rapid suppression in LH secretion. Thus in quail, unlike some mammals, the photoperiodic control over gonadotrophin secretion is independent of the reproductive status of the animal at the time of castration. The results confirm the view that changes in sensitivity of the hypothalamo-pituitary axis to gonadal steroids are not a primary factor in the neural mechanisms underlying photoperiodism in quail.


1934 ◽  
Vol 27 (10) ◽  
pp. 1395-1406 ◽  
Author(s):  
Max Cheval

Recent experience has convinced the author of the value of ovarian grafting. He gives the histories of a number of women upon whom he made implants of their own ovarian tissue in the course of operations for double oöphorectomy. The subsequent state of these patients is contrasted with that of women after castration without grafting. When the uterus was left in position menstruation was re-established in over 80% of the grafted cases. The author and his co-workers maintain that the vitality of autogenous grafts of ovarian substance is enhanced by hormones produced by the uterine mucosa. He therefore advocates that grafts of uterus be made in conjunction with ovarian implants whenever possible. Experiments carried out on animals have proved the correctness of this opinion. The results of a series of cases of combined ovarian and uterine graftings are recorded, and the technique of uterine mucosa implants is described.


1984 ◽  
Vol 102 (2) ◽  
pp. 133-141 ◽  
Author(s):  
R. Bhanot ◽  
M. Wilkinson

ABSTRACT We have attempted to clarify the physiological involvement of endogenous opiates in the steroid-mediated control of gonadotrophin release. Our studies showed that there was an acute reduction in the inhibitory effects of endogenous opiates on LH and FSH release following gonadectomy in the rat. This was indicated by a significant reduction in the ability of naloxone to stimulate serum LH/FSH levels (sampled at 15 min) in 26-day-old female rats 48 h after ovariectomy. Luteinizing hormone was highly sensitive to the inhibitory effects of the synthetic met-enkephalin analogue, FK 33-824, at this time (sampled at 90 min). An unexpected observation was that long-term absence of gonadal steroids also disrupted the ability of exogenous opiates, FK 33-824 and morphine, to influence LH release. This was seen as an inability of FK 33-824 (1·0 or 3·0 mg/kg) to inhibit LH secretion. The effects of gonadectomy on opiate control of LH occurred at all developmental stages and were not due to a disruption of sexual maturation. Opiate involvement in prolactin secretion did not appear to be adversely affected by an absence of gonadal steroids. Another novel aspect of this work was that the opiatergic component in the control of gonadotrophin secretion could be reinstated in long-term gonadectomized rats by treatment with oestradiol benzoate or testosterone propionate. Similarly, priming with increasing dosages of oestradiol benzoate which resulted in progressively lower LH levels gave larger naloxone responses. This steroid–opiate interdependency suggests that the negative feedback influence of gonadal steroids on LH secretion is conveyed, in part, by hypothalamic opiate peptides. Our results therefore provide a neurochemical basis for gonadal steroid negative feedback. J. Endocr. (1984) 102, 133–141


Author(s):  
Elena A. Omelchenko

The problems of adaptation and integration of ethnic migrants into the Russian society become more and more acute, due to the intensification of migration processes in the modern world and the involvement of the Russian Federation in them. Nearly 38 million children participate in the international migration, and many of them meet difficulties with the access to qualitative education, and have to pass through an enduring and tricky way of linguistic, cultural, social and psychological adaptation. The structure of conventional cultural and communicative, natural and geographical contacts, interactions of a child with his family and relatives is destroying, a child is stressed and experiences the crisis of identity, has to rethink and reinvent values and social regulations. The listed problems contribute to the increase of social disadaptation of ethnic migrants’ children; generate the situation of their potential failure in the future. Inside the society, accepting migrants, these problems complicate the structure of interethnic relations and links, and sometimes it becomes a ground for inter-ethnic tension. In the Russian Federation, the problem of adaptation of children from the families of ethnic migrants also becomes quite urgent, especially in the sphere of education. The author of the article has been researching this theme during the latest 20 years, and in 2019–2020 this research is made in the frames of the project “Integration of the children of ethnic migrants’ families via education: the methodical and consultative support of schools and kindergartens in the regions of the Russian Federation”, where 32 educational organizations in ten regions participate. The article illustrates a series of problems connected with the adaptation of migrant children, using the materials of the research made in the Ryazan’ and Kaluga regions. These children are mostly migrants of one-and-a-half or the second generation, and their families came to Russia from Kyrgyzstan, Uzbekistan, Azerbaijan and Tajikistan. Several paragraphs refer to the problems of adaptation to school of the Gypsy children. Basing on the results of the analysis, the author names main restrictions that prevent schools from the organization of intensive work aimed at linguistic, social and cultural adaptation of ethnic migrants’ children. She also defines main problems restraining the integration of the children from ethnic migrants’ families into the Russian educational environment and Russian society.


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