Magneto-optical system for high speed real time imaging

A new magneto-optical system has been developed to expand the range of high speed real time magneto-optical imaging. A special source for the external magnetic field has also been designed, using a pump solenoid to rapidly excite the field coil. Together with careful modifications of the cryostat, to reduce eddy currents, ramping rates reaching 3000 T/s have been achieved. Using a powerful laser as the light source, a custom designed optical assembly, and a high speed digital camera, real time imaging rates up to 30 000 frames per seconds have been demonstrated.

Endometrial pathology in postmenopausal tamoxifen treatment: comparison between gynaecologically symptomatic and asymptomatic breast cancer patients

AIMS

To evaluate whether endometrial pathology is more likely to be diagnosed in gynaecologically symptomatic rather than in gynaecologically asymptomatic postmenopausal breast cancer patients with tamoxifen treatment; and to evaluate the possible influence of various clinical factors on the incidence of endometrial pathology.

METHODS

Endometrial histological findings, transvaginal ultrasonographic endometrial thickness, demographic characteristics, health habits, and risk factors for endometrial cancer were compared between 14 gynaecologically symptomatic (group I) and 224 gynaecologically asymptomatic (group II) postmenopausal breast cancer patients with tamoxifen treatment.

RESULTS

Overall, 28.6% of the study population had endometrial pathology. The incidence of overall positive endometrial histological findings was significantly higher in group I than in group II (92.9% v 24.6%, p < 0.0001). Atrophic endometrium was more common in group II than in group I (75.3% v 7.1%, p < 0.0001). Most other endometrial pathology was significantly more common in group I than in group II (endometrial hyperplasia, 35.7% v 5.6%, p < 0.0001; endometrial polyps, 35.7% v 13.4%, p < 0.0111; endometrial carcinoma, 21.5% v 0.9%, p < 0.0001). Endometrial pathology appeared considerably later in the gynaecologically asymptomatic patients than in gynaecologically symptomatic patients (p = 0.0002). Vaginal bleeding or spotting occurred exclusively in group I. The incidence of endometrial pathology in the entire study population was consistent with that reported elsewhere, and higher than that reported for healthy postmenopausal women.

CONCLUSIONS

Endometrial pathology is more likely to be diagnosed in gynaecologically symptomatic postmenopausal breast cancer patients with tamoxifen treatment, and after a shorter duration of time, than in gynaecologically asymptomatic patients.

Dose-dependent effect of tamoxifen therapy on endometrial pathologies in postmenopausal breast cancer patients

To assess whether a higher cumulative tamoxifen dose is associated with increased incidence of various types of endometrial pathologies, we compared cumulative dose of tamoxifen treatment as well as demographic characteristics, risk factors for endometrial cancer, transvaginal ultrasonographic endometrial thickness, and various treatments for the primary breast cancer between 159 postmenopausal breast cancer tamoxifen-treated patients without endometrial pathologies (group I) and 67 similar patients with endometrial pathologies (group II). A similar comparison was made between group I patients and similar patients with proliferative endometrium (group IIa), with endometrial hyperplasia (group IIb), with endometrial polyps (group IIc), and with endometrial cancer (group IId). Overall cumulative tamoxifen dose was significantly higher in group II as compared to group I (27.4+/-33.4 and 17.4+/-20.2, respectively; P<0.0252). Transvaginal ultrasonographic endometrial thickness was significantly higher in group II than in group I patients (16.3+/-11.3 mm and 12.1+/-6.3 mm, respectively; P<0.0147). The frequency of diabetes mellitus, of previous postmenopausal bleeding, and of previous exposure to hormone replacement therapy was significantly higher in group II than in group I patients (P<0.001, P<0.0001 and P<0.001, respectively). There were no significant differences in all parameters tested between group I, group IIa, group IIb, group IIc, and group IId. However, there was an obvious trend for higher cumulative tamoxifen dose in patients with benign endometrial pathologies as compared to those without endometrial pathologies or to those with endometrial cancer (Group I = 17.4+/-20.2 g, group IIa = 22.5+/-18.5 g, group IIb = 28.1+/-20.3 g, group IIc = 31.4+/-42.7 g and group IId = 10.4+/-12.6 g). Endometrial pathologies, except for endometrial cancer, are associated with a high cumulative dose of tamoxifen in postmenopausal breast cancer patients.

Influence of adipose tissue distribution on the biological activity of androgens

To establish whether the conversion of androstenedione (A) to estrogens and 5 alpha-reduced metabolites in human adipose tissue was determined by the site of origin of the tissue, studies were carried out on adipose stromal cells from different body sites. Adipose tissue was obtained from the breast, omentum, abdomen, lower thigh, upper thigh, buttock, and flank from patients undergoing liposuction for cosmetic reasons or at surgery. Stromal cells were isolated after incubation of the adipose tissue with collagenase and were grown in culture using alpha-minimal essential medium (MEM) + 15% fetal calf serum. Studies of A metabolism were carried out when the cells were between days 4 and 12 in culture. After an 8-hour incubation with (3H)-A as substrate, estrone (E1), testosterone (T), 5 alpha-androstanedione (5 alpha-A-dione), androsterone (AND), and dihydrotestosterone (DHT) were isolated using thin layer and paper chromatography. The conversion per 1 x 10(6) cells of A of E1 was more than 10-fold greater in the upper thigh, buttock, and flank than in the breast, lower thigh, abdomen, or omentum (0.13-3.0 vs 0.01-0.09%). The formation of 5 alpha-reduced androgens varied from 0.86-10% and was similar in tissue from different body sites. Cortisol (10(-7) M) stimulated E1 formation 3- to 10-fold in cells from all sites, whereas 5 alpha-reductase activity was either unchanged or increased moderately (up to twofold). In cells from the abdomen, omentum, and lower thigh, the formation of 5 alpha-reduced androgens was more than 10-fold greater than the formation of E1. In cells from the upper thigh, buttock, and flank, E1 formation was comparable to 5 alpha-reduced androgen formation. These studies show marked differences in the relative conversion of A to estrogens and 5 alpha-reduced androgens in adipose stromal cells depending on their site of origin, and they suggest that the distribution of body fat may be a major factor in determining the biologic effects of secreted androgens.

Steroid modulation of aromatase activity in human cultured breast carcinoma cells

Cortisol and steroids with progestational or androgenic activity were studied to determine the effects of these steroids on the conversion of androstenedione (A) to estrone (E1) in human cultured breast carcinoma cells. Cortisol (10(-6) M) stimulated aromatase activity in two estrogen unresponsive cell lines (MD, DM) and in an estrogen responsive cell line (MCF7) with the maximum stimulation occurring during confluence. Cortisol inhibited the replication of MCF7 cells but not MD and DM. Dihydrotestosterone, androsterone and 5 alpha-androstanedione (10(-6) M) inhibited the conversion of A to E1 by greater than 90% under basal and cortisol stimulated conditions. Progesterone (10(-6) M) had no effect on aromatase activity while the progestational agent R5020 (10(-6) M) produced a 30% inhibition. The anabolic steroids 19-nortestosterone and 19-norandrostenedione which also have progestational activity inhibited the conversion of A to E1 in a dose dependent manner with 90% inhibition at 10(-6) M. Danazol (10(-6) M) a drug with both androgenic and progestational activity inhibited E1 formation by 30%. Under the same conditions, the known inhibitor of aromatase, 4-hydroxyandrostenedione (10(-6) M) decreased E1 formation by more than 90% and aminoglutethimide (10(-6) M) caused only 25% inhibition. These studies demonstrate that endogenous and exogenous steroids may have significant effects in modulating the local formation of estrogens from androgen precursors in cultured breast carcinoma cells. This effect on estrogen formation may be a factor in the biological response of breast tissue.

Aromatase activity in the breast and other peripheral tissues and its therapeutic regulation

Studies using [3H]androstenedione (A) demonstrated that this substrate can be aromatized to estrone (E1) in homogenates of breast carcinoma tissue and breast adipose tissue, in breast carcinoma and breast adipose stromal cells in culture, and in cultured adipose stromal cells from sites remote from the tumor. Using cultured breast carcinoma cells, it was shown that estrogen formation was stimulated by cortisol (10(-6) M) and inhibited by endogenous 5 alpha-reduced androgens: 5 alpha-androstene-dione greater than androsterone greater than dihydrotestosterone greater than epiandrosterone greater than 3 alpha- and 3 beta- androstanediol. It was also shown that 19-nortestosterone and 19-norandrostenedione (10(-6) M) inhibited E1 formation by 80%. Progesterone (10(-6) M) had no effect on aromatase activity, while the progestational agent R5020 (10(-6) M) caused a 70% inhibition. These studies emphasize that a variety of compounds can influence aromatase activity and that drugs which are used as aromatase inhibitors in patients with breast carcinoma may have multiple sites of action.

The relationship between aromatase activity and body fat distribution

The metabolism of androstenedione (A) to estrone (E1) and 5 alpha-reduced androgens was studied in stromal cells derived from human adipose tissue from different body sites. The tissue was obtained from non-obese patients undergoing cosmetic liposuction or at the time of surgery for reduction mammoplasty. The conversion of A to E1 per 1x 10(6) cells was between 6- and 30-fold greater in the upper thigh, buttock, and flank than in the abdomen. These differences were present in primary culture and persisted to at least the third subculture. Estrogen formation in breast adipose tissue was similar to that found in cells from abdominal fat. The formation of 5 alpha-reduced metabolites (5 alpha-androstenedione, androsterone, and dihydrotestosterone) varied from patient to patient but was similar in cells from different body sites. These studies show that the regional distribution of fat may influence the metabolism of androgens in adipose tissue, with upper body fat tending to form a lower ratio of estrogens to 5 alpha-reduced androgens than lower body fat.

The formation of 5 alpha-reduced androgens in stromal cells from human breast adipose tissue

The present study was designed to determine if stromal cells derived from human breast adipose tissue contain 5 alpha-reductase activity, and to study the effect of 5 alpha-reduced androgens on aromatase activity under basal and cortisol stimulated conditions. Stromal cells were prepared from breast adipose tissue obtained at the time of surgery from four patients. The cells were isolated after collagenase digestion and were cultured in alpha-minimum essential medium with 15% fetal calf serum. Studies were carried out between days 4 and 11 of the third subculture in the presence or absence of cortisol (10(-6) M). Metabolism of androstenedione (A) was studied over a period of 8 h after addition of medium containing 20 X 10(6) dpm (100 pM) [3H]A. The cells metabolized A to estrone (E1), testosterone (T), 5 alpha-androstane 3, 17-dione (5 alpha-A-dione), androsterone (AND), and dihydrotestosterone. On day 7 of culture, product formation expressed as percent conversion of A per 1 X 10(6) cells ranged as follows: E1, 0.02-0.13; T, 0.12-0.36; 5 alpha-A-dione, 2.05-9.91; and a fraction containing AND and dihydrotestosterone, 0.38-0.59. In the presence of cortisol the rate of cell growth was decreased by 25% to 50%. The formation of E1 increased 150- to 1500-fold and AND formation increased 2- to 8-fold. There was no consistent change in the formation of 5 alpha-A-dione and T. The addition of 5 alpha-A-dione (10(-6) M) to the culture medium at the time of assay resulted in greater than 90% inhibition of E1 formation under both basal and cortisol stimulated conditions. The studies indicate that adipose tissue is an important site for the formation of 5 alpha-reduced androgens.

The relationship between growth and androstenedione metabolism in four cell lines of human breast carcinoma cells in culture

The conversion of androstenedione (A) to estrogens, testosterone (T) and 5 alpha-reduced metabolites was studied in different phases of cell growth in 4 lines of cultured human breast carcinoma cells. Aromatase activity was 10-fold greater in MD and DM than in MCF7 cells and was undetectable in ZR75 cells. Estrogen formation in MD and DM lines increased during the phase of exponential growth and decreased to 20% of maximum during confluence. 5 alpha-Reductase activity was determined by the formation of 5 alpha-androstane-3,17-dione (5 alpha-A-dione) and androsterone (AND), and was 5-fold greater in ZR75 cells than MD cells and 2-fold greater than in MCF7 cells. This activity was relatively constant during exponential growth and decreased during confluence. T accumulation was inversely related to 5 alpha-reductase activity. The MCF7 and ZR75 cells which contain estrogen receptors had the highest levels of 5 alpha-reductase activity while the MD line which lacks estrogen receptors had the lowest 5 alpha-reductase activity. The assessment of aromatase and 5 alpha-reductase activity in addition to estrogen and progesterone receptors may be helpful in predicting hormone sensitivity in human breast tumours.

The intracellular control of aromatase activity by 5 alpha-reduced androgens in human breast carcinoma cells in culture

Four cell lines, each derived from a primary tumor from a patient with breast carcinoma, were grown to confluence in alpha-Minimum Essential Medium with 15% fetal calf serum and incubated for 24 h with [3H]androstenedione. The two lines (SA and PP) with the lowest formation of estrone and estradiol (less than 0.1% conversion) were the most active in the formation of the 5 alpha-reduced androgen metabolites androsterone (AND), 5 alpha-androstanedione (5 alpha-A-dione), and dihydrotestosterone (DHT). The two lines with the highest aromatase activity (DM and MD) had the lowest formation of 5 alpha-reduced metabolites. To determine if the 5 alpha-reduced androgen metabolites formed within the breast carcinoma cells could influence aromatase activity, the MD line was further studied. After 24-h preincubation with AND, DHT, or 5 alpha-A-dione at concentrations of 10(-6), 10(-7), and 10(-8) M, [3H]androstenedione was added to the culture medium, and aliquots were removed at 0, 4, 8, and 24 h. An 8-h incubation period was found to be optimum for inhibition studies. In comparison to control levels of estrone (2.5%) and estradiol (0.35%) formation, inhibition of aromatization was evident with all three compounds at 10(-8) M, with 5 alpha-A-dione producing the greatest inhibition (50%). At 10(-7) M, inhibition ranged from 45% (AND) to 70% (5 alpha-A-dione), and at 10(-6) M, inhibition was greater than 90% for each compound. 5 alpha-A-dione produced slightly greater inhibition than AND or DHT at each concentration tested. Since each of these compounds was capable of inhibiting aromatization, the cumulative effect of these 5 alpha-reduced metabolites could be an important factor in the intracellular regulation of aromatase activity.

Androstenedione metabolism in epithelial cells derived from early-lactation human milk

Epithelial cells derived from duct epithelium were cultured from early lactation human milk in medium supplemented with 15% fetal calf serum, insulin (0.3 u/ml), cortisol 21-sodium succinate (6 micrograms/ml) and amikacin (50 micrograms/ml). The capacity of these cells to metabolize androstenedione to estrone, estradiol and C19 metabolites was studied during continuous culture. After extraction of the medium, the products were subjected to phenolic partition and separated by thin-layer and paper chromatography, followed by recrystallization to constant specific activity. The study demonstrated a progressive increase in the formation of estrone and testosterone over the first 24 h in culture, while estradiol formation showed an initial 2-4 h lag, then increased slowly. The C19 compounds identified were androsterone, 5 alpha-androstanedione, epiandrosterone, dihydrotestosterone and etiocholanolone. 5 alpha-Androstanedione and androsterone were the major 5 alpha-reduced metabolites. Since these cells are derived from normal duct epithelium, their metabolic characteristics may be more representative of normal breast tissue than those of tissue removed from patients with pathological breast disorders.

The metabolism of androstenedione and testosterone to C19 metabolites in normal breast, breast carcinoma and benign prostatic hypertrophy tissue

In previous studies from our laboratory of the metabolism of androstenedione (A) and testosterone (T) in breast adipose and breast carcinoma tissue, the aromatization of these compounds, and their interconversion were demonstrated. The present study describes the conversion of androstenedione and testosterone to C19 metabolites in homogenates of normal breast tissue and breast carcinoma tissue and examines the C19 metabolites in homogenates of benign prostatic hypertrophy (BPH) tissue under similar conditions. Tissue homogenates were incubated for 90 min in Krebs-Ringer bicarbonate buffer (pH 7.4) with ATP (3 mM) and NADPH (2.4 mM) as co-factors. Following extraction with ethyl acetate, the metabolites were separated into neutral and phenolic fractions. Identification of specific products was made by thin layer and paper chromatography and recrystallization procedures. The formation of C19 metabolites was 10-fold greater in prostate than in breast tissue. Androsterone was the major product of androstenedione in both breast and prostate. The other 5 alpha-metabolites of androstenedione identified were dihydrotestosterone (DHT) and epiandrosterone (EPI). The 5 beta-metabolite, etiocholanolone (ET10), was identified in both breast and prostate following incubation with androstenedione. Using testosterone as substrate, dihydrotestosterone was the major product in normal breast and BPH. Etiocholanolone was detected in breast, but not in prostate following incubation with testosterone. Aromatization was demonstrated in all incubations with breast tissue, but not in prostate. The results indicate that androstenedione is actively metabolized by both breast and prostate to 5 alpha reduced metabolites. They also identify the formation of etiocholanolone in both tissues. Aromatization was demonstrated only in breast tissue.

Aromatase in human breast carcinoma

Breast carcinoma tissue is capable of forming estrogens from circulating androgen precursors. In this study, aromatase was examined in homogenates of breast adipose and breast carcinoma tissue, in normal and abnormal parenchymal breast tissue, and in breast carcinoma cells in culture. Homogenates of carcinoma tissue showed a wide range of activity in the conversion of adrostenedione to estrone. The mean conversion in carcinoma tissue was greater than that seen in parenchymal tissue from patients with gynecomastia and mammary dysplasia. Homogenates of breast adipose tissue from patients with benign and malignant disorders showed comparable aromatase activity. Three cell lines isolated from a primary breast carcinoma differed in their aromatase activity demonstrating a heterogeneity of aromatase activity in cells from a single tumor. Studies of aromatase activity in breast carcinoma cells in culture over a period of 8 hr demonstrated progressive estrone formation. Testosterone formation from androstenedione was noted in all studies using both homogenates and cell cultures. Testosterone formation from androstenedione was approximately 10-fold greater than was the formation of estrone from androstenedione in all studies. The metabolism of androstenedione to other androgens examined in homogenates of normal and carcinomatous breast tissue revealed that the major products were androsterone, 5 beta-androsterone, dihydrotestosterone, and epiandrosterone. Both estrogen and androgen formation within the cell may be important in determining the cellular response.

Effects of 4-hydroxy-4-androstene-3, 17-dione and 10-propargylestr-4-ene-3, 17-dione on the metabolism of androstenedione in human breast carcinoma and breast adipose tissues

The effects of 4-hydroxy-4-androstene-3, 17-dione (4-OH-A) and 10-propargylestr-4-ene-3, 17-dione (PED) on the aromatization of androstenedione (A) and the conversion of A to testosterone (T) were studied in incubations with breast carcinoma and breast adipose tissues. Parallel studies were carried out to determine the effects of 4-OH-A and PED on A metabolism in tissue from 5 patients with breast carcinoma. At 11 micro M, both compounds fully inhibited aromatization, whereas the conversion of A to T was decreased in only 2 incubations. Studies with varying concentrations of 4-OH-A and PED demonstrated that both compounds inhibited estrone (E1) formation by 80% at a concentration of 0.085 micro M, with maximum effect at 0.34 micro M. 90% inhibition of estradiol (E2) formation was observed at inhibitor concentrations of 0.17 micro M or greater. T formation was slightly affected at 0.67 microM, but was progressively inhibited with increasing 4-OH-A or PED concentrations, reaching 70% at 11 micro M. Similar experiments with 4-OH-A in breast adipose tissue homogenates showed that a concentration of 0.1 micro M was sufficient to inhibit aromatization while T inhibition required 11 micro M. 4-OH-A and PED are selective inhibitors of aromatization in human breast tissues and may provide a mechanism for controlling estrogen responsive processes.

Androgen metabolism in male and female breast tissue

Incubation studies have been carried out using normal breast tissue and breast tissue from patients with gynecomastia, mammary dysplasia and breast carcinoma to determine the pattern of androstenedione metabolism. All tissues formed estrone (E1) and testosterone (T) in all incubations. Estradiol (E2) was isolated in incubations of tissue from 1 of 6 patients with mammary dysplasia, 5 of 6 patients with gynecomastia and in all incubations with normal and carcinoma tissue. Estrone formation was lowest in mammary dysplasia and gynecomastia, and higher in apparently normal breast tissue. The greatest E1 formation was found in incubations with breast carcinoma tissue, although there was considerable variation within this tissue group. Estradiol formation was low in all tissues, with the highest conversion rates in carcinoma tissue. Testosterone formation in carcinoma tissue was greater than in mammary dysplasia or gynecomastia, but similar to apparently normal tissue. These results indicate that breast tissue from different pathological states varies in its capacity to aromatize androstenedione (A) to estrogenic products and to convert it to other androgens. They have also shown that the pattern of metabolism is distinctive for the nature of the pathological abnormality.

Antibodies to a phyto-oestrogen: antigenicity of genistein coupled to a synthetic polypeptide

An antigen containing the phyto-oestrogen genistein (5,7,4′-trihydroxyisoflavone) was prepared by coupling genistein-2-carboxylic acid to a copolymer of tyrosine, glutamic acid and lysine. Immunization of rabbits with this antigen resulted in the production of antibodies to the carrier and to the hapten. Genistein-specific antibodies were isolated by means of an immunoadsorbent containing genistein linked to a heterologous carrier; these reacted with genistein-containing antigens in the passive cutaneous anaphylaxis, complement fixation and 125I-labelled antigen binding tests. The antibodies failed to cross-react with oestradiol-17β coupled to ovalbumin.

The reaction of the genistein—polypeptide conjugate with the purified antibodies was inhibited by genistein and by the closely related oestrogenic isoflavone biochanin-A. No such inhibition was produced by oestradiol-17β, nor were the anti-genistein antibodies capable of binding 14C-labelled oestradiol.

The potential use of immunization with isoflavone conjugates for the protection of livestock against phyto-oestrogens is discussed.