Incidence Of Atresia Research Articles

Role of atresia in establishing the follicular hierarchy in the ovary of the domestic hen (Gallus domesticus).

At peak laying periods the ovary of the domestic hen contained 30-100 small yolky follicles with diameters varying between 1 and 8 mm. In general, the number of these healthy follicles decreased with increasing size in that there were about 20 follicles with a diameter of 1-2 mm and 1 follicle (mean less than 1) with a diameter of 7-8 mm. The number of follicles with diameters greater than 8 mm (the hierarchy of large, yolky follicles) varied between 4 and 7. By using a dye-marker, growth from 3 to 5 mm was estimated to take 3 days, from 5 to 8 mm, 2 days and from 8 mm to ovulation, 6 days. No information was obtained for growth between 1 and 3 mm because the dye did not enter these smaller follicles. Between 5 and 25 small yolky follicles were atretic. The reduction in the number of follicles with time and the high incidence of atresia suggests that this is a normal fate of small yolky follicles in birds with a high rate of lay. In marked contrast, only one large yolky follicle was observed to be atretic throughout the whole experiment. These two very different levels of atresia serve to define two distinct groups of follicles in the size range studied. Ovulation rate appears to be the product of two complementary mechanisms, one for the initiation of growth and the other controlling the rate at which the small yolky follicles are lost through atresia.

Effect of vegetable oil factory effluent on ovarian recrudescence in the fresh water teleost, Channa punctatus (BI.)

The effect of chronic exposure of sublethal concentration (5%) of vegetable oil factory effluent on ovarian maturation of Channa punctatus was studied. The process of ovarian recrudescence was significantly retarded as evidenced by the low ovarian weights and low occurrence of Stage III (Yolky) oocytes in the ovaries of effluent-exposed fish. A high incidence of atresia was also noticed in the ovaries of fish exposed to the effluent.

Development of nonovulatory antral follicles in heifers: changes in steroids in follicular fluid and receptors for gonadotropins.

The objective of this study was to examine changes in steroid concentrations in follicular fluid (FF) and in gonadotropin receptors in nonovulatory follicles that develop after ovulation in heifers. Six groups of six to seven heifers were ovariectomized on days 3, 5, 7, 9, 11, and 13 of an estrous cycle. Follicles 6 mm or more in diameter were separated into two classes, estrogen-active (E-A) and estrogen-inactive (E-I). E-A follicles had higher concentrations of estradiol than progesterone and androgens in FF and a low incidence of atresia. E-I follicles had higher concentrations of progesterone or androgens than estradiol in FF and a high incidence of atresia. Diameters, numbers of granulosa cells, and capacities of granulosa cells and thecal tissue to bind [125I]iodo-hCG increased in E-A follicles from days 3-7. During this time, diameters, numbers of granulosa cells, concentrations of estradiol, and capacities of granulosa cells and thecal tissue to bind gonadotropins were greater in E-A than E-I follicles. On days 9, 11, and 13, each heifer had only a single E-I follicle. Compared with E-A follicles on day 7, E-I follicles on days 9, 11, and 13 were smaller and had less granulosa cells, less estradiol in FF, and a lower capacity to bind [125I]iodo-hCG. After day 7, E-A follicles were not observed until day 13. We conclude that at least two periods of growth and atresia of follicles occur between days 3-13 of an estrous cycle in heifers. One is during days 3-7 when a single E-A follicle 6 mm or more in diameter develops and all other E-I follicles regress. The other is between days 7 and 13 when the E-A follicle from day 7 becomes an E-I follicle and regresses, and another E-A follicle develops.

Meconium Peritonitis - Observations in 115 Cases and Antenatal Diagnosis

In 20 years the authors have met with 115 cases of meconium peritonitis (MP). The high incidence in China is shown. In all cases there were intraabdominal calcifications. There were no cases of fibrocystic disease. The authors classify 3 types: 1. Neonatal obstructive type 41 cases. 2. Free perforation with: Free pneumoperitoneum 15 cases. Localized pneumoperitoneum 23 cases. 3. No signs or symptoms, with potential intestinal obstruction 23 cases. The series shows a low incidence of atresia. The authors suggest necrotizing enterocolitis as a cause because of the high incidence of stenosis. Three prenatally diagnosed cases are discussed. All had hydramnios and fetal abdominal calcifications. Two of these were confirmed after birth. The mortality is high (42.6%). Abdominal x-ray in all cases with polyhydramnios may lead to a positive diagnosis of MP.

Gonadotropin Receptors of the Ovine Ovarian Follicle during Follicular Growth and Atresia1

The binding of [125I]-labeled human follicle stimulating hormone ([125I]-FSH) and chorionic gonadotropin ([125I]-hCG) to intact ovine follicles was studied in vitro as a function of follicular diameter and stage of morphological atresia. Histological confirmation of the atretic classification was established and the incidence of atresia in those follicles studied was variable and directly related to follicular diameter (P<0.01). The binding of [125I]-hFSH and [125I]-hCG to theca was relatively constant when compared to the change in granulosa binding that was associated with increased follicular diameter or stage of atresia. When studied without regard to the stage of atresia, the binding of [125I]-hFSH to granulosa cells decreased and that of [125I]-hCG increased with increased follicular diameter. These changes were thought to reflect changes in the relative incidence of atresia within each size group rather than decreased binding per se. Subsequent analysis of [125I]-labeled gonadotropin binding to granuhosa cells as a function of both follicular diameter and stage of atresia simultaneously indicated that the extent of [125I]-hFSH binding was determined solely by stage of atresia rather than follicular diameter (P<0.05). Conversely, while [125I]-hCG binding was decreased by increased atresia, the overall extent of binding was determined by follicular diameter (P<0.01). It is concluded that macroscopic assessment of follicular atresia in ovarian follicular populations is directly related to follicular diameter. In addition, the ability of granulosa cells to bind [125I]-labeled gonadotropins in vitro varies as a function of follicular diameter and stage of atresia.

Reproductive patterns in seventeen species of warmwater fishes in a Missouri River reservoir

The timing of ovarian maturation and spawning of 17 warmwater fish species in Lake Oahe (South and North Dakota) was estimated from changes in the mean ovary indices (ratios of ovary weight to fish length). The onset of vitellogenesis varied within species (up to 2 months). Maturation of the ova took from 7.5 to 10 months, depending on species. Annual variations in the mean date of peak spawning of individual species during 1964–1971 were usually less than a week. There was little overlap of the annual mean peak spawning dates of the 17 species, and an established sequence of spawning among species was shown. A relatively high incidence of atresia in the shovelnose sturgeon, northern pike, and carp indicated that these species had apparently not yet adapted to the altered and variable spawning conditions in this reservoir. Regularity of spawning would seem to provide the best chance for spawning success in variable environments such as Lake Oahe.

Histogenesis of atretic ovarian follicles in a seasonally breeding bird.

AbstractHistologic examination of ovaries from a non‐migratory population of scrub jays (Aphelocoma coerulescens) disclosed a marked annual cycle in the incidence of atresia. Atretic follicles became more common as the nesting season progressed and were most abundant immediately after the cessation of breeding. Atresia involved a dissociation of granulosa cells and movement of these cells into the follicle. Subsequently, granulosa cells showed steatogenesis and ultimately disappeared simultaneously with the invasion of the follicle by ex‐thecal gland cells. The data suggest that the diverse histology of avian atretic follicles reflects different stages in the process of atresia rather than multiple origins. Ovarian stromal glands apparently arise both from ex‐thecal gland cells of atretic follicles and stromal connective tissue. A possible secretory role of atretic follicles is considered.

Histological Studies of Ovaries in Rats Treated with Hydroxyurea, Triphenyltin Acetate, and Triphenyltin Chloride1

Three insect chemosterilants, hydroxyurea, triphenyltin acetate, and triphenyltin chloride, were tested to determine their effect on ovarian tissue in the albino rat. The compounds were administered orally at dosage rates of 40 mg per kg per day for hydroxyurea, and 20 mg per kg per day for the 2 organotin compounds for periods of 4, 9, 14, 19, and 24 days. Animals were killed on the day following cessation of treatment and histological preparations of ovaries were made and evaluated. Hydroxyurea had no significant effect on the ovarian tissue and no side effects were detected. However, both triphenyltin compounds produced significant changes in the ovarian tissue. Among these changes were a decreased number of mature follicles, an increased incidence of atresia in early follicle growth, and a pronounced decrease in the number of corpora lutea present. This last effect was regarded as a decrease in ovulation, and thus, a decreased fertility. This effect, as well as the others listed above, was present on or by the 1st 5-day sample period.

THE RELATION BETWEEN OVULATION FREQUENCY AND THE INCIDENCE OF FOLLICULAR ATRESIA FOLLOWING SURGICAL OPERATIONS IN THE DOMESTIC HEN

THE REPORTS in the literature dealing with follicular atresia in the ovary of the bird have been largely confined to morphological descriptions of the process (Davis, 1942; Pearl and Boring, 1918; Dubuisson, 1906) and to mention of some of the agents which bring it about. Examples of these are environmental disturbances, (Stieve, 1918); injections of various steroids (Dunham and Riddle, 1942), subovulatory doses of pituitary preparations (Fraps and Dury, 1942), dried tissue preparations and egg white, proteins, and protein derivatives (Fraps and Neher, 1945); and operations on the ovary (Rothchild and Fraps, 1944). In none of these studies, however, was the incidence of atresia shown to be related to any of the variables within the population of birds treated with one of these agents. The present communication will attempt to do this, and will show that one of the most important factors which determines the incidence of atresia after abdominal operations is the birds’ frequency of ovulation preceding operation, and that the incidence of atresia varies in inverse proportion to this factor.