New concepts in ovarian regulation: an immune insight

Localization of epidermal-type fatty acid binding protein in macrophages in advanced atretic follicles of adult mice

The localization of epidermal-type fatty acid binding protein (E-FABP) in the mature mouse ovary was examined by immuno-light and electron microscopy. Numerous macrophages immunopositive for both anti-E-FABP and F4/80 antibodies, together with immunonegative cells, were found in advanced atretic follicles that had eccentric lumens containing deformed ova. While some E-FABP-immunopositive macrophages were spider in shape and appeared singly, others, especially close to the lumen, were round and voluminous and tended to be aggregated. The voluminous macrophages contained phagosomes of various sizes and they were regarded as those actively involved in the phagocytosis of apoptotic granulosa cells. E-FABP-immunopositive macrophages and their processes were often apposed to adjacent immunonegative cells, and some of them lined the lumen containing deformed ova. On the other hand, E-FABP-immunonegative cells in the atretic follicles were classified into two types: the one, a minority, was characterized by small mitochondria containing non-tubular cristae and presumably represented residual granulosa cells, while the other dominant type was characterized by large mitochondria containing tubular cristae and presumably represented theca cells originally surrounding the follicles to be atretic. The present detection of E-FABP-immunopositivity selectively in macrophages of the atretic follicles suggests possible involvement of E-FABP and/or its ligand fatty acids in the process of follicular atresia, and it makes more reliable the identification of the advanced atretic follicles with the antral spaces obliterated, which could provide further details on the histology of the follicular atresia than before.

Academic stress, immunological reaction, and academic performance among students of nursing and physiotherapy

The associations among health status, health behavior, and changes in human cytomegalovirus (HCMV) specific salivary antibodies during academic stress were investigated in relation to academic achievement among nursing and physiotherapy students. Fifty-four first year students donated saliva samples and completed a pencil and paper questionnaire before (t1), during two term examinations (t2 and t3), and after grades were posted (t4). An increase in the level of specific salivary HCMV IgG and IgA antibodies from t1 to t2, and a decrease from t2 to t4 were related to academic success. Health status and health behavior remained fairly stable during the stress period. The results are congruent with the inverted U-shape model of stress and learning suggested by Yerkes & Dodson (1908).

Epstein-Barr virus specific salivary antibodies as related to stress caused by examinations

Epstein-Barr virus (EBV) is prevalent in 90% of the population. After primary infection it remains in a latent state and the majority of the virus carriers are asymptomatic during their life. Among the immunocompromized patients such as organ and bone marrow transplant recipients, individuals lacking T cell immunity, and patients treated with corticosteroid, cancer, and AIDS patients EBV primary infection and reactivation can cause life threatening diseases. Immunosupression may occur also during stressful events, which induce corticosteroid release and thus activate EBV. The effect of examination stress on EBV reactivation among female students was studied by detecting the values of EBV specific IgG and IgA salivary antibodies. Sequential saliva samples were obtained from first year female students before, during, and after two important examinations. EBV specific IgG and IgA salivary antibodies were tested by enzyme-linked immunosorbent assay (ELISA). Hepatitis A virus (HAV) salivary antibodies served as a non-latent virus control. A statistically significant increase in the values of EBV specific IgG and IgA antibodies was detected in samples collected during the examinations, as compared to the samples collected two months before and one month after the exams (P < 0.05). HAV antibody levels did not change significantly between the four time points. The menstrual cycle had no significant effect on the results. No significant symptoms were reported during the whole study. These results indicate that among female students who endure stress during academic examinations, a significant increase in EBV specific IgG and IgA salivary antibody values could be detected. EBV reactivation should be confirmed by measuring salivary EBV DNA or infectious virus.

Intra-ovarian regulation of oocyte developmental competence in cattle

Each oestrous cycle the ovary produces one or more oocytes, depending on the species considered, which are fully competent to sustain the development of a new individual and are defined as matured. Ovulation is the terminal phase of a lengthy and complex selection process which enables only a minute proportion of the oocytes present in the ovary to be ovulated and possibly fertilised. The use of exogenous gonadotrophins for the pharmacological stimulation of the ovaries has clearly indicated that oocytes naturally excluded by the selection process can also be matured and, if fertilisedin vivoorin vitro, can generate normal offspring.

Quantitative changes in macrophage distribution in normal mouse ovary over the course of the estrous cycle examined with an image analysis system

PROBLEM

The current study considered the distribution of macrophages within the major ovarian structures throughout the estrous cycle.

METHODS

Immunohistochemical analyses were carried out using an avidin-biotin-peroxidase staining method and the rat anti-mouse macrophage monoclonal antibody anti-Mac-l was applied to stain macrophages. A computer-assisted image analysis system was used to quantify and compare the distribution of macrophages within individual ovarian structures during the estrous cycle. The following morphological structures were analyzed: primordial, preantral, antral, pre-Graafian, and atretic follicles; first-, second-, and third-generation corpora lutea; and the interstitium. The analysis included follicular and corpus luteum substructures: theca, granulosa cells, and interstitium. The system allows the estimation of macrophage distribution as a macrophage density per microns2 of the defined area.

RESULTS

Primordial and preantral follicles did not contain macrophages during all stages of the estrous cycle. In antral, pre-graafian, and graafian follicles, macrophages were located and quantified only in the theca and were not detected in the granulosa cell layer. In contrast, atretic follicles showed macrophage localization in both thecal and granulosa cell layers. Macrophages were present in small numbers in the granulosa luteal cell layer and in high numbers in the thecal layer of newly developing corpora lutea. In the second generation of corpus luteum, macrophages followed the same pattern of distribution, while old corpora lutea contained significantly higher numbers of macrophages in both thecal and luteal cell layers. Surprisingly, significant quantitative changes in the macrophages distribution were detected over the course of the estrous cycle. Macrophage density was significantly higher in proestrus and metestrus when compared with the density in diestrus and estrus in most of the studied substructures with the exception of atretic follicles. Atretic follicles showed high macrophage density throughout the cycle with a two-fold higher density at metestrus.

CONCLUSION

Macrophages were present in the mouse ovary over the course of the estrous cycle. The greatest numbers of macrophages appearing in corpora lutea and in atretic follicles suggest a role for macrophages in corpus luteum differentiation and follicular atresia. Their patterns of distribution at proestrus and metestrus within microenvironmental compartments suggests a functional correlation with the events of ovarian development.

Relationship between anticomplement in seminal plasma and complement in follicular fluid associated with outcome in an in vitro fertilization program

PURPOSE

The study was conducted to evaluate levels of anticomplement in seminal plasma and levels of complement in follicular fluid, in correlation with fertilization and pregnancy rate after in vitro fertilization and intracytoplasmic sperm injection programs.

MATERIALS AND METHODS

Anticomplement levels were determined in 70 couples undergoing in vitro fertilization therapy. In 15 of these couples, complement levels were measured. Anticomplement and complement levels were also determined in an additional 21 couples (apart from the 70 couples) undergoing intracytoplasmic sperm injection treatment.

RESULTS

A correlation was found between fertilization rate and anticomplement levels in the seminal plasma (r = 0.4, P < 0.01) after standard in vitro fertilization. No correlation was found in the intracytoplasmic sperm injection group, or observed between complement levels and any parameter examined in both groups. Pregnancy occurred only in those couples with an anticomplement:complement ratio below 0.49.

CONCLUSIONS

Determination of anticomplement and complement levels may contribute to the assessment of a successful outcome of in vitro fertilization/intracytoplasmic sperm injection.

Mitogenic factors of corpora lutea

The mammalian corpus luteum (CL), which plays a central role in the reproductive process because of its production of hormones such as progesterone, appears to be an exceptionally dynamic organ. Its rate of growth and development are extremely rapid and, even when the CL is functionally mature, its rate of cell turnover remains relatively high. Associated with this high rate of cell turnover, the mature CL receives the greatest blood supply per unit tissue of any organ, and also exhibits a relatively high metabolic rate. Although numerous growth factors have been identified in luteal tissue, their role in growth and differentiation of this dynamic organ remains unclear. Recently, while attempting to identify mitogenic factors of ovine and bovine CL, we have found that they produce several mitogens during the estrous cycle as well as pregnancy. The majority of these luteal-derived mitogenic factors are heparin-binding, and although some may represent previously identified factors, several appear to be novel heparin-binding growth factors. Isolation and purification of mitogenic factors produced by the CL will enable us to determine their roles in luteal growth, development and differentiated function, which will contribute to our understanding not only of the regulation of fertility but also of tissue growth and development in general.