Different origins of two corpora lutea recovered from a pregnant African elephant (Loxodonta africana).

Elephant ovaries contain multiple corpora lutea (CLs) throughout pregnancy. Two CLs (P-1 and P-2) collected from a pregnant African elephant were used to investigate their origin and physiological state in this study. The mRNA expressions of prolactin receptor, CYP11A and inhibin betaB subunit were higher in P-2 than in P-1, while LHCGR and inhibin betaA subunit mRNA were higher in P-1 than in P-2. Protein expression of cleaved caspase-3 was detected in P-1 but not in P-2. These results suggest different origins for the two CLs in this one pregnant elephant, and we also demonstrated the production of bioactive prolactin by the elephant placenta.

The progression of small-follicle reserves in the ovaries of wild African elephants (Loxodonta africana) from puberty to reproductive senescence.

This study aimed to determine whether the follicle reserve in the ovary of the African elephant declines progressively after puberty and whether its depletion constrains the fertility of older females. Elephant ovaries were fixed in 4% neutral buffered formalin and small-follicle counts made using stereological protocols. Excepting a slight rise in small-follicle numbers between 16 and 25 years of age, there was a trend for follicle numbers to fall from puberty to 70 years. Reproductive status did not impact significantly on small-follicle numbers (P=0.31). The number of early primary follicles, initially higher in number than true primary follicles, fell from post-puberty to nil at 45 years of age. Six of the seven oldest animals in the study showed signs of recent ovarian activity in the form of antral follicles, corpora lutea or large corpora nigra. The four oldest elephants (mean age 69 years) had a median small-follicle count of 11,113. In summary, it appears that the elephant ovary is capable of supplying oocytes for ovulation right up to the time of death at the age of maximum life expectancy, although the follicle reserve becomes depleted in some older elephants.

Ovarian and placental morphology and endocrine functions in the pregnant giraffe (Giraffa camelopardalis).

Gross, histological and immunocytochemical examinations carried out on maternal and fetal reproductive tissues from two pregnant giraffes at an estimated 8 and 13.5 months of gestation (term=15 months) revealed a typically ruminant macrocotyledonary placenta with binucleate trophoblast cells scattered sparsely in the placentome where they stained intensely with a prolactin antiserum. Binucleate cells were present in greater numbers in the intercotyledonary allantochorion where they did not stain for prolactin whereas the uninucleate trophoblast still did. A single large corpus luteum of pregnancy and several small luteinised follicles were present in the maternal ovaries while the fetal ovaries at 13.5 months gestation showed an assortment of enlarging antral follicles and partially and completely lutenised follicles, the granulosa and luteal cells of which stained positively for 3ß-hydroxysteroid dehydrogenase (3ß-HSD), 17,20 lyase, prolactin, progesterone receptor and androgen receptor, but negatively for aromatase. The uninucleate trophoblast of the placentome and intercotyledonary allantochorion, the epithelium of the maternal endometrial glands, the seminiferous epithelium in the fetal testis at 8 months of gestation and the zonae fasciculata and reticularis of the fetal adrenal at 13.5 months also stained positively for 3ß-HSD and negatively for aromatase. Endocrinologically, it appears that the giraffe placenta is more similar to that of the sheep than the cow with a placental lactogen as the likely driver of the considerable degree of luteinisation seen in both the maternal and the fetal ovaries.

Development of the germinal ridge and ovary in the African elephant (Loxodonta africana).

The follicular reserve and its ontogeny in the elephant are of interest because elephants have the longest reproductive life of all land-based mammals. They also have the longest recorded pregnancy, which allows a protracted view of the series of significant events involved in the development of the embryonic and fetal gonads. The large elephant population of Zimbabwe provided the opportunity to collect conceptuses from elephants culled for management reasons and hunted professionally. Five embryos aged 76-96 days and the ovaries of four fetuses aged 4.8-11.2 months were fixed in 4% buffered formalin and studied by conventional histological sectioning and a stereological protocol to calculate the follicle reserve of each fetus. These observations enabled the conclusion that the migration of primordial germ cells into the indifferent gonad terminates at around 76 days of gestation while entry of oogonia into meiosis along with first follicle formation starts at around 5 months. Peak numbers of follicles are present by mid-gestation towards the end of the 6-month mitotic-meiotic transition period. It appears that the cortex of the elephant fetal ovary at mid-gestation (11 months) has already reached a developmental stage exhibited by the ovaries of many other mammals at full term.

Luteal maintenance of pregnancy in the African elephant (Loxodonta africana).

The ovaries of eight African elephant foetuses and their mothers between 2 and 22 months of gestation, and those of two cycling and two lactating elephants, were examined grossly, histologically and immunocytochemically, with emphasis on the development and regression of accessory corpora lutea (CL) of pregnancy and the steroidogenic capacities of the accessory CL and the foetal ovaries. The results supported recent findings that the accessory CL form as a result of luteinisation, with and without ovulation, of medium-sized follicles during the 3-week inter-luteal period of the oestrous cycle. They enlarge significantly and become steroidogenically active around 5 weeks of gestation, probably in response to the placental lactogen which is secreted by the implanting trophoblast of the conceptus. The large luteal cells stained strongly for 3ß hydroxysteroid dehydrogenase (3ßHSD) activity throughout the 22-month gestation period although they showed vacuolation and other degenerative changes in the final months of gestation coincident with hypertrophy and hyperplasia of 3ßHSD-positive interstitial cells in the foetal gonads. It is proposed that the progestagens secreted by the enlarged gonads of the elephant foetus may function both to assist the maternal ovaries in supporting the pregnancy state and to induce torpor and intrauterine immobility of the rapidly growing foetus.

Placentation in the African elephant (Loxodonta africana). V: the trophoblast secretes placental lactogen.

OBJECTIVES: To determine if elephant placenta secretes a lactogenic hormone which may function as the principal luteotrophin to maintain ovarian luteal function throughout gestation. STUDY DESIGN AND MAIN OUTCOME MEASURES: To label biopsies of endometrium and placenta recovered from African elephant culled professionally throughout gestation with an anti-human prolactin polyclonal antibody in a conventional immunocytochemical staining technique. RESULTS: All trophoblast cells covering the placental villi and forming 'plugs' in the apical endometrial glands stained strongly and precisely with the anti-human prolactin antiserum throughout gestation. CONCLUSIONS: Elephant trophoblast secretes a placental lactogen (elPL) which may stimulate both the development and secretory function of the large accessory corpora lutea of elephant pregnancy and provide the mitogenic stimulus for placental differentiation and development.

Paediatric oncology and intensive care treatments: changing trends.

OBJECTIVES: To review the outcome of patients with childhood malignancy requiring intensive care treatment and to assess whether there is any secular trend for improved outcome. DESIGN: Retrospective chart reviews of 74 consecutive admissions to a paediatric intensive care unit from a regional paediatric oncology centre between 1990 and 1997. During the same period there were 6419 admissions to the oncology unit, 814 of whom were new cases. RESULTS: The overall survival at discharge from the intensive care unit was 49 of 74. Patients with either systemic or respiratory infection requiring ventilation had the poorest survival (13 of 31) whereas postoperative patients had the best survival (15 of 15). However, patients with respiratory or systemic infection who required inotropic support with more than three agents all died compared with about one quarter of those needing no inotrope. All patients with systemic or respiratory infective illness were neutropenic and positive microbiological identification was possible in 13 of 21 and five of 18, respectively. Non-survivors had a higher mean acute physiology and chronic health evaluation system (APACHE-II) score than survivors (24.2 v 15.94, respectively) but no patient with a score of > 27 survived. CONCLUSION: Compared with previous series, there has been a great improvement in survival of oncology patients admitted to the intensive care unit especially those with either systemic or respiratory infection needing ventilation. Full intensive care treatment should be provided for these patients.