John-Gunnar Forsberg

A morphologist's approach to the vagina — age-related changes and estrogen sensitivity

This paper reviews basic facts on vagina histology and ultrastructure with respect to passage of different substances and drugs through the epithelium. Particular interest is devoted to the action mechanism of topically-applied vaginal estrogen, its binding to receptors in different vaginal cell types, and possible local metabolic routes. Differences in estrogen sensitivity between uterus and vagina are discussed as well as the background for the high vaginal sensitivity.

Immunohistochemical studies on the expression and estrogen dependency of EGF and its receptor and C-fos proto-oncogene in the uterus and vagina of normal and neonatally estrogen-treated mice.

The final target cell response to estrogen is dependent not only on the estrogen receptor, but also on autocrine/paracrine interactions with growth factors (e.g., EGF) and proto‐oncogenes (e.g., c‐fos). Because neonatal estrogen treatment results in permanent changes in the female mouse genital tract (permanent vaginal cornification, cervical adenosis and tumors, changed growth control mechanisms in uterus), it was of interest to study possible acute and permanent effects of such treatment on distribution and levels of EGF, its receptor (EGF‐r), and c‐fos and to relate such changes to morphological development and appearance of epithelial abnormalities.

Short-term and long-term effects of estrogen on lymphoid tissues and lymphoid cells with some remarks on the significance for carcinogenesis

Estrogens have long been thought to play a role in regulating the immune system. The difference in some types of immune responses between males and females is well-known, as is the pronounced thymic involution induced by exogenous estrogens. Estrogens stimulate some aspects of macrophage activity and, depending on dose and mitogen, inhibit or stimulate lymphocyte proliferative response in vitro. Another example is the estrogen effect on the delayed type hypersensitivity response. A broad review is given of such estrogen effects on lymphoid tissue and immune response. Most of the studies published so far are phenomenological. However, the recent description of estrogen receptors in the thymus and in some lymphocyte subpopulations, as well as a deeper understanding of regulating factors in the immune system, open the possibility of a more detailed understanding of the estrogen mechanism of interference.Estrogen effects in adults are reversible. After treating neonatal mice with the synthetic estrogen diethylstilbestrol (DES), disturbances are induced in lymphocyte populations and lymphocyte functions which are permanent and irreversible. Lymphocytes from adult, neonatally DES-treated female mice have a reduced mitogen response to ConA and LPS (T and B cell mitogen) and the delayed type hypersensitivity response is depressed. A detailed analysis demonstrated a decreased T helper cell population. The activity of Natural Killer cells is permanently reduced and this functional impairment is related to a decreased number of these cells, in turn determined at the bone marrow level. The same animals have an increased sensitivity to chemical carcinogens (methylcholanthrene) and they spontaneously develop epithelial changes in the uterine cervix which morphologically are similar to adenocarcinoma. The association between estrogen-associated malignancy and estrogen effects in lymphocyte functions deserves further study.

The Different Responses of the Female Mouse Thymus to Estrogen after Treatment of Neonatal, Prepubertal, and Adult Animals

Contrary to the common description of estrogen-induced thymus atrophy we have observed a thymus enlargement after treatment of neonatal female mice with estrogen. We now describe an age-dependent difference in the estrogen response (enlargement, atrophy) as well as mechanisms relevant to the response. Groups of female NMRI mice were treated with estrogen (diethylstilbestrol, DES) at different 5-day periods in prepubertal (day 1-5, day 6-10, day 30-34) or postpubertal life (days 48-52). All the treatment groups showed a reduced thymus weight 4 days after the last treatment but later responses differed. Neonatal DES treatment resulted in an ovary-independent thymus enlargement 8 weeks after the treatment when the cortical part was relatively larger than in controls; treatment on days 30-34 was followed by a rebound type of regeneration; the acute weight reduction after treatment on days 48-52 was normalized 16 days later. Neonatal DES treatment transiently depressed the number of thymic S phase cells 4 days after the treatment while apoptosis was similar in controls and DES females. The estrogen receptor pattern was not affected by DES. The number of white blood cells was temporarily depressed while the bone marrow cellularity was still reduced in 8-week-old females. Neonatal treatment with an LH-releasing hormone antagonist reduced thymus weight at 8 weeks but had no effect on the DES-induced enlargement. The delayed-type hypersensitivity response developed differently in controls and DES females. The thymus enlargement after neonatal estrogen treatment could be the result of an increased immigration of precursor cells into the thymus and/or a defect maturation/emigration mechanism. Further studies on different cell subsets are necessary to explain the mechanism behind the thymus enlargement.

Pregnancy and delivery characteristics of women whose infants develop child cancer

Data on all cancers among children born 1973–1984 were extracted from the Swedish Cancer Registry and linked to data in the Medical Birth Registry (1,268 cancer cases). For each case, two controls were selected, matched for maternal age, parity, county, and month of birth. A marginally increased risk of childhood malignancy was seen in the offspring of teenage mothers and at parity 1 and 4+. There was an excess among cases of the diagnosis physiological icterus. No statistically significant associations were found between childhood malignancy and infant sex, twinning, birthweight, non‐chromosomal malformations, maternal smoking, or complications during pregnancy.

Acute and permanent growth effects in the mouse uterus after neonatal treatment with estrogens

Acute and late effects of neonatal estrogen treatment were studied in NMRI mice treated with diethylstilbestrol (DES) or estradiol-17 beta (E2) on days 1 to 5 after birth (estrogenized females). The uterine wet weight (UWW) response in 6-day-old females, after 5 daily treatments with DES, had a peak at a daily dose of 10(-2) micrograms DES and declined with higher doses. Females (26-day-old) treated with DES or E2 neonatally had a reduced UWW response to a challenge with DES; on a dose basis, DES was more effective neonatally than E2. A single injection with DES or E2 in the neonatal period stimulated mitotic activity in the uterine horn epithelium; the UWW response to a 24-h DES pulse increased from day 2 to 6 after birth, but the uterine epithelial mitotic rate response decreased. Epidermal growth factor (EGF) was a more potent stimulator of mitotic activity than DES or E2. DES inhibited mitotic activity in the uterine cervical epithelium; EGF protected from this DES effect. In adult estrogenized females, EGF-induced uterine stimulation of 3H-thymidine incorporation subsided more rapidly than in control females; uterine epithelium did not respond to EGF in vitro. Uterine stroma of adult estrogenized females is postulated to house a population of cells under nonovarian proliferation control while the uterine epithelium may be under influence of an ovary-dependent proliferation inhibiting factor that is gradually lost under culture conditions.

The activity of acid and alkaline phosphatase during the development of the vaginal anlage in rat and mouse

SummaryThe authors have studied the activity of alkaline and acid phosphatase in the rat and the mouse vaginal anlage. The activity is high in the epithelium of the müllerian vagina and low or uncertain in that of the sinus vagina. When a lumen is formed in the latter, there appears in rat an activity of both phosphatases of the same intensity as seen in the müllerian vagina. In mouse, the epithelium of the müllerian vagina transitory loses its activity of alkaline phosphatase when the epithelium undergoes transformation. The whole vagina is then surrounded by a zone of high stromal activity of alkaline phosphatase. The epithelium lacks activity except in the fornix region where the activity remains in a zone close to the lumen Thereafter the activity disappears in the subepithelial strorna and instead apears in the basal layer of the epithelium. The activity of acid phosphatase increases in the mouse sinus vagina at the same time as lumen is formed, being of the same intensity here as in the müllerian vaginal part.

On the occurrence of 5-hydroxytryptamine containing cells in the vaginal and vestibular epithelium of the rabbit

SummaryIn the vestibular and stratified vaginal epithelium from rabbit, the authors have demonstrated the occurrence of 5-HT-containing cells. Moreover, the same cells also contain a rich amount of acid phosphatase.

Some remarks on degeneration granules in the genital sphere.

SummaryBy using different methods of staining the authors have made a closer study of the various stages in the process of cell degeneration that take place in the urogenital tract. In the beginning of this cell degeneration the nuclei remnants are Feulgen positive, becoming later, however, Feulgen negative, and accumulating finally into larger conglomerations possessing the same staining-qualities as the cytoplasm.

Failure to Detect a Second-Generation Effect in Female Mice after Neonatal Treatment with an Estrogen (Diethylstilbestrol)

Inbred female mice of the NMRI strain were treated subcutaneously with 5 micrograms diethylstilbestrol (DES) in olive oil or vehicle only for the first 5 days after birth. One group of DES-treated females was killed at the age of 8-12 weeks, and the uterine cervix and adjacent parts of the vagina and uterine horns prepared for histological studies. In all preparations, the cervical epithelial lining contained regions with heterotopic columnar epithelium (HCE) along 69-100% of the length of the common cervical canal. Ovaries from neonatally DES-treated females were grafted to 8-week-old ovariectomized control hosts and these hosts were mated to control males 2 weeks later. The hosts gave birth to normal-sized litters. The female offspring from these litters had a normal cervical epithelial lining and, in turn, gave birth to normal-sized litters. These results indicate that treatment of neonatal female mice with DES does not affect the female germ cells as far as concerns factors associated with the development of HCE or reduced fertility in the next generation.