Relationship between steroid receptors (as continuous variables) and response to adjuvant treatments in postmenopausal women with node-positive breast cancer.

In current clinical practice for breast cancer patients, estrogen (ER) and progesterone receptor (PgR) concentrations, quantified by the dextran-coated charcoal assay, are categorized by an arbitrary cutoff into a negative or positive status. However, although the results obtained with this approach are easy to interpret, such a representation could oversimplify the relationship between ER and PgR content and patient outcome and imply an assumption of monotonicity, which is generally expected but rarely proven. We evaluated the relationship between ER and PgR content (considered on a continuous scale) and clinical outcome, using a flexible statistical model, in a group of postmenopausal patients with N-positive operable tumors who were submitted to surgery and different adjuvant treatments (tamoxifen or CMF). Univariate analysis indicated that in the tamoxifen-treated group, ER level, number of metastatic nodes (pN) and age, but not PgR, were significant indicators of clinical outcome (p = 0.032, p = 0.021 and p = 0.029, respectively). Multivariate analysis indicated that in this group of patients there was no interaction between variables, and in the final model for disease-free survival (DFS) only ER and pN were retained with an overall predictive ability of the regression model of 0.723, as evaluated by Harrell's c. However, pN markedly contributed to the predictive ability of the model with respect to ER, since a marked decrease in Harrell's c statistic (c = 0.582) was observed when pN was removed from the model. In the CMF-treated group, only pN affected clinical outcome. When the estimated DFS curves obtained from the final Cox regression models were plotted according to four values of ER (in the tamoxifen-treated group) or three values of pN (in the CMF-treated group) we observed that in the tamoxifen-treated group patients with an ER concentration equal to 0 fmol/mg cytosol protein had the worst prognosis, whereas a marked improvement of the expected DFS was observed for patients with a low but detectable ER level (generally classified as ER-negative because falling below the conventional cutoff value of 10 fmol/mg cytosol protein). Our results seem to suggest that the use of steroid receptor concentrations on a continuous scale, instead of dichotomous "status", is to be preferred in the choice of adequate therapeutic strategies.     

Estrogen and androgen receptors in the liver of cynomolgus monkeys (Macaca fascicularis)

Estrogen receptors (ER) and androgen receptors (AR) were evaluated in the hepatic cytosol from cynomolgus macaques to determine if there were differences associated with gender and endogenous hormone secretion. Saturable, high affinity binding (Kd = 0.2-0.8 nM) was demonstrated for both ER and AR from either male or female monkeys. Displacement of tritiated estradiol from the ER was estrogen specific (including ethinyl estradiol). Both androgens and the synthetic progestins (levonorgestrel and norethindrone) displaced tritiated mibolerone from the AR. Both 8S and 4S molecular forms of ER and AR were demonstrated on 5-20% sucrose density gradients. The ER levels were higher in females in the follicular phase of the menstrual cycle (40.5 +/- 1.9 fmol/mg protein) than levels in males (26.4 +/- 4.8 fmol/mg protein; P less than 0.01) or levels in luteal phase females (31.8 +/- 2.4 fmol/mg protein; P less than 0.05). AR levels were not different between females during different phases of the menstrual cycle (65.8 +/- 4.6 and 69.5 +/- 4.3 fmol/mg protein, follicular and luteal, respectively), but there was a tendency (P less than 0.10) for the levels in males (54.4 +/- 6.6 fmol/mg protein) to be lower than female levels. The demonstration of saturable, high affinity binding of androgens and estrogens in liver tissue of these primates, along with differences associated with gender and the stage of the menstrual cycle, suggests that hepatic receptors are functional and may play an important role in hepatic protein secretion.     

Estrogen receptor determination in fine needle aspirates of the breast. Correlation with histologic grade and comparison with biochemical analysis

Material obtained by fine needle aspiration (FNA) of 25 surgically removed breast carcinomas was tested for the immunocytochemical localization of estrogen receptor (ER) using the peroxidase-antiperoxidase method and a monoclonal antibody developed against human breast cancer ER. The results were compared to those obtained by the conventional biochemical analysis of cytosol protein. A semiquantitative relationship between the immunoperoxidase stain and the biochemical analysis suggests that cases in which greater than 70% of the cells stain and in which intense staining is present are likely to contain ER in a concentration of greater than 250 fmol/mg of cytosol. Less than 15% stained cells and an absence of intense staining is indicative of a concentration of less than 10 fmol/mg. In only one case was there a significant difference in positivity between the two methods, possibly as a result of a functional heterogeneity of the tumor cell population. Intense staining is strongly suggestive of a tumor of low histologic grade and was never seen in tumors with a high histologic grade or nuclear grade. The immunoperoxidase method of ER detection on material obtained by FNA is a semiquantitative means of selecting patients with breast cancer who are likely to respond to hormonal therapy. The method overcomes many important disadvantages of cytosol analysis and provides clinically significant information regarding the ER content and the degree of tumor differentiation.     

Estrogen and progestin receptors in human uterus: reference ranges of clinical conditions

Estrogen receptor (ER) and progestin receptor (PR) levels and their respective dissociation constants (Kd) were determined by titration assay and Scatchard analyses in 319 human uteri. Levels of receptors were neither age nor uterine weight dependent. ER was higher in postmenopausal patients while PR levels were lower in women under 25 years of age. ER ranged from undetectable to 560 fmol/mg cytosol protein (mcp) while PR levels were generally 10-fold greater with a mean of 791 fmol/mcp. The mean of the Kd of ER was 4.0 X 10(-10) M while that for the PR was 9.2 X 10(-10) M. Receptor levels were not correlated with their respective Kd values nor with the Kd of the other receptor; therefore ligand affinities were not receptor concentration dependent. A population of patients was identified (12.5% of the total) in which the ER levels were undetectable while their corresponding PR ranged from 38 to 2,100 fmol/mcp. This suggests the existence of a type of PR which may not require ER for its expression and is independent of the phase of the cycle. Both ER and PR content were significantly elevated in the proliferative phase of the cycle. Evaluation of results as a function of histopathological features showed no relationship between the ER and PR of patients with anovulatory bleeding versus pathology. Uteri with leiomyomas contained ER and PR at levels comparable to those of histologically normal uteri. Adenomyosis patients tended to have lower ER and higher PR levels than the normal uteri. Reference ranges have been established for these receptors in uteri as a corollary to studies of these proteins in endometrial cancer.     

The use of fine needle aspirates in the evaluation of progesterone receptor content in breast cancer

Material obtained by fine needle aspiration (FNA) from 30 surgically removed breast carcinomas was tested for the immunocytochemical localization of progesterone receptor (PR) using a monoclonal antibody (MAb) developed against human breast cancer PR. When compared to values obtained by conventional biochemical analysis of cytosol protein in the same tissue, a semiquantitative relationship suggested that a high intensity (3+) stain in cases in which more than 30% of the cells were positive was compatible with a PR concentration of greater than 200 fmol/mg. An absence of nuclear stain was indicative of a PR concentration of less than 10 fmol/mg, while a stain of an intermediate intensity (2+) or a stain of high intensity (3+) in less than 30% of the cells correlated with a PR level of 51-200 fmol/mg. Only one case in this group showed weak staining with a PR concentration of 85.5 fmol/mg. Cases containing a low concentration of PR (less than 50 fmol/mg) demonstrated a weak nuclear stain (1+) in less than 10% of the cells. Localization of nuclear PR by MAb staining of FNA cytologic specimens affords a relatively simple, inexpensive method of obtaining potentially significant information regarding tumor response to hormonal therapy and the recurrence potential of a tumor in patients with primary breast cancer; at the same time, this technique obviates several important disadvantages of conventional biochemical analysis.     

Correlation of mean nuclear area with estrogen receptor content in aspiration cytology of breast carcinoma

Thin needle aspirates of 42 consecutive breast carcinomas were obtained at the time of excisional biopsy. Nuclear diameters of 100 cells from each case were measured, and the nuclear areas were calculated. The concomitantly acquired histologic sections were reviewed and assigned a histologic grade according to the National Surgical Adjuvant Breast Project protocol no. 4. Estrogen receptor (ER) content was analyzed by both the DCCA and SDGA techniques. The ER content of each case was then compared to both the mean nuclear area of the cells on the cytologic smears and the histologic grade. All 16 cases with mean nuclear areas of less than 60 sq micrometer contained significant levels of ER (greater than 10 fmol/mg protein), as did 6 of 11 cases with nuclei between 60 and 90 sq micrometer. Only 5 of 15 cases with nuclei larger than 90 sq micrometer contained significant ER levels. Comparison of the sensitivity, specificity and predictive values of both techniques suggests that a quantitative assessment of nuclear area in cytologic thin needle aspirates correlates more closely with ER content than does histologic grading.     

Changes in bromodeoxyuridine labeling index during radiation treatment of an experimental tumor

Cell proliferation kinetics in a spontaneous mouse fibrosarcoma (FSaII) growing in C3H mice has been studied by in vivo pulse labeling of cells synthesizing DNA with bromodeoxyuridine (BrdUrd). A monoclonal antibody to BrdUrd and flow cytometry were used to quantify these cells. Labeling indices (LI) were measured before and after radiation. Unirradiated 10-mm tumors had a mean LI of 17.5%. After a single dose of 20 Gy there was depression of LI after 1 day followed by a rapid increase to greater than control values after 5 days. Analysis performed after five fractions showed that LI was dependent on the dose per fraction and interval between fractions. After 5 and 7 Gy/fraction LI remained similar to control values during daily fractionation but was significantly depressed after twice daily fractionation. With doses greater than 10 Gy/fraction there was marked depression of LI using both fractionation schedules. These changes in LI correlated well with changes in tumor volume after radiation. Tumors were also biopsied after 5 fractions of a 20-fraction course to see if LI would predict for tumor control. LIs of greater than or equal to 10% were associated with lack of tumor control at 90 days while all controlled tumors had a significant depression of LI. Changes in LI after radiation were a reasonable indication of the amount of repopulation occurring and might be useful in selecting patients for altered fractionation schedules.     

Effect of interleukin-6/interferon-beta 2 on glucocorticoid action in rat hepatoma cells

Reuber hepatoma cells (RHC) were treated 4 h with dexamethasone (dex), with and without simultaneous fibroblast-conditioned medium (cIL-6). A cytosol fraction, prepared in the presence of molybdate and dithiothreitol, was analyzed for [3H]dex (20 nM) binding in the presence and absence of 1 microM dex at 4 degrees C. Receptor levels declined from 76.0 fmol/mg at zero dex to 28.8 fmol/mg at 10 nM dex, and to 11.8 fmol/mg at 1 microM dex (P less than or equal to 0.05). cIL-6 plus 10 nM dex lowered binding to 18.3 fmol/mg (P less than or equal to 0.05), and treatment with cIL-6 alone diminished binding to 9.8 fmol/mg (P less than or equal to 0.05). Thus, cIL-6 diminished the number of available glucocorticoid receptors.     

Characterization and Regional Distribution of α2-Adrenoceptors in Postmortem Human Brain Using the Full Agonist [3H]UK 14304

The full agonist [3H]UK 14304 [5-bromo-6-(2-imidazolin-2-yl-amino)-quinoxaline] was used to characterize alpha 2-adrenoceptors in postmortem human brain. The binding at 25 degrees C was rapid (t1/2, 4.6 min) and reversible (t1/2, 14.1 min), and the KD determined from the kinetic studies was 0.48 nM. In frontal cortex, the rank order of potency of adrenergic drugs competing with [3H]UK 14304 or [3H]clonidine showed the specificity for an alpha 2A-adrenoceptor: UK 14304 approximately equal to yohimbine approximately equal to oxymetazoline approximately equal to clonidine greater than phentolamine approximately equal to (-)-adrenaline greater than idazoxan approximately equal to (-)-noradrenaline greater than phenylephrine greater than (+/-)-adrenaline much greater than corynanthine greater than prazosin much greater than (+/-)-propranolol. GTP induced a threefold decrease in the affinity of [3H]UK 14304, with no alteration in the maximum number of binding sites, suggesting that the radioligand labelled the high-affinity state of the alpha 2-adrenoceptor. In the frontal cortex, analyses of saturation curves indicated the existence of a single population of noninteracting sites for [3H]UK 14304 (KD = 0.35 +/- 0.13 nM; Bmax = 74 +/- 9 fmol/mg of protein). In other brain regions (hypothalamus, hippocampus, cerebellum, brainstem, caudate nucleus, and amygdala) the Bmax ranged from 68 +/- 7 to 28 +/- 4 fmol/mg of protein. No significant changes in the KD values were found in the different regions examined. The binding of [3H]UK 14304 was not affected by age, sex or postmortem delay.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thyroid hormone levels in the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex.

Hypothalamic-pituitary dysfunction and thyroid gland cytomegalovirus inclusions have been described in patients with the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC). We evaluated 80 patients with AIDS or ARC for the frequency of hypothalamic-pituitary or thyroid gland failure and altered serum thyroid hormone levels due to nonthyroidal disorders. One patient had subclinical hypothyroidism. Of these patients, 60% had low free triiodothyronine (T3) index values and 4% had low free thyroxine (T4) indexes; none of the latter had hypothalamic-pituitary or thyroid gland failure, since all serum cortisol values were greater than or equal to 552 nmol per liter (greater than or equal to 20 micrograms per dl) and all thyrotropin levels were less than or equal to 3 mU per liter (less than or equal to 3 microU per ml), respectively. Those who died had lower total T4 and T3, free T3 index, and albumin levels than those discharged from hospital. Serum total T4 and T3 levels correlated with albumin levels and total T3 with serum sodium levels. Serum total T3 levels best predicted the outcome of the hospital stay (accuracy = 82%). Thus, abnormal serum thyroid hormone levels in AIDS or ARC patients are most frequently due to nonthyroidal disorders, but hypothalamic-pituitary or thyroid gland failure may occur.     

An investigation of cut-points for primary breast cancer oestrogen and progesterone receptor assays

Oestrogen and progesterone receptor (ER and PgR) assay values are frequently used in medical decision-making for breast cancer patients. We have proposed statistical standardization of receptor assay values to improve inter-laboratory comparability, and now report the use of standardized log units (SLU) to investigate the effects of ER and PgR cut-points on time to first recurrence outside the breast (DFS). Between 1980 and 1986, there were 678 primary breast cancer patients treated at the Henrietta Banting Breast Centre (HBBC). The effects of ER and PgR cut-points were examined with multivariate analyses considering the variables: age, tumour size, nodal status, weight and adjuvant treatment. We considered receptor assay cut-points ranging from −1.0 to +1.0 SLU (ER between 7 and 166 fmol/mg protein; PgR between 7 and 181 fmol/mg protein). PgR was included in the multivariate prognostic models more often than ER, although patients had a better prognosis with both larger ER and PgR values. There was no best cut-point for ER or PgR, and there was strong evidence that ER and PgR should be considered as continuous rather than dichotomous (negative, positive) variables. Patient prognosis should also be more comparable with SLU.     

Binding of Brain and Atrial Natriuretic Peptides to Cultured Mouse Astrocytes and Effect on Cyclic GMP

125I-Porcine brain natriuretic peptide (125I-pBNP) bound to mouse astrocytes in primary culture in a time-dependent manner (t1/2 = 4.5 min), similar to 125I-human atrial natriuretic peptide (125I-hANP) (t1/2 = 5 min). Binding was saturable and reached equilibrium after 90 min at 22 degrees C for both radioligands. Scatchard analysis suggested a single class of binding sites for pBNP with a binding affinity and capacity (KD = 0.08 nM; Bmax = 78.3 fmol/mg of protein) similar to those of hANP1-28 (KD = 0.1 nM; Bmax = 90.3 fmol/mg of protein). In competition binding studies, pBNP or human/rat atrial natriuretic peptide (ANP) analogues [hANP1-28, rat ANP1-28 (rANP1-28), and rANP5-28] displaced 125I-hANP, 125I-pBNP, and 125I-rANP1-28 completely, all with IC50 values of less than nM (0.14-0.83 nM). All four peptides maximally stimulated cyclic GMP (cGMP) production by 10 min at 22 degrees C at concentrations of 1 microM with EC50 values ranging from 50 to 100 nM. However, maximal cGMP induction by brain natriuretic peptide (BNP) (25.9 +/- 2.1 pmol/mg of protein) was significantly greater than that by hANP1-28 (11.5 +/- 2.2 pmol/mg of protein), rANP1-28 (16.5 +/- 2.0 pmol/mg of protein), and rANP5-28 (15.8 +/- 2.2 pmol/mg of protein). These studies indicate that BNP and ANPs act on the same binding sites and with similar affinities in cultured mouse astrocytes. BNP, however, exerts a greater effect on cGMP production. The difference in both affinity and selectivity between binding and cGMP production may indicate the existence of receptor subtypes that respond differentially to natriuretic peptides despite similar binding characteristics.     

Epidermal growth factor receptor (EGFr) as a marker for poor prognosis in node-negative breast cancer patients: Neu and tamoxifen failure

Analysis of EGFr and ER was performed on tumour samples from 231 patients with operable breast cancer followed for up to 6 yr after surgery. The median duration of follow-up in patients still alive at the time of analysis was 45 months.

Thirty-five percent of patients (82) had tumours greater than 10 fmol/mg ¹²⁵I-EGF binding (EGFr⁺) and 47% (109) had cystolic ER concentration >5 fmol/mg (ER⁺), with a marked inverse relationship between EGFr and ER (P<0.00001). EGFr was second only to axillary node status as a prognostic marker for all patients both in terms of relapse-free and overall survival (P<0.001, logrank EGFr⁺ vs EGFr⁻).

For patients with histologically negative axillary nodes EGFr was superior to ER in predicting relapse and survival (P<0.01 and P<0.005, respectively, compared to P<0.1 and P<0.1, logrank). In a multivariate (Cox model) analysis only EGFr, out of EGFr, ER, size and grade, was predictive for either relapse-free or overall survival for patients with node-negative disease (P=0.052 and P=0.026, respectively).

The correlation of neu expression with response to tamoxifen in patients with recurrent disease was assessed immunochemically. Response rate was reduced in the presence of neu from 50 to 17% for ER⁺ cases and from 26 to 0% for ER⁻ cases.     

Calcium flux across disk membranes. Studies with intact rod photoreceptors and purified disks

Calcium accumulation by rod disks was studied in excised bullfrog retinas with 45Ca tracer-exchange methods. Ca uptake by disks is a necessary requirement if light-induced Ca releases from disks mediate photoreceptor excitation. In an hour-long incubation, disks exchanged less than or equal to 0.01 mole of Ca per mole of rhodopsin, or less than or equal to 10% of their total Ca. This corresponds to a unidirectional flux of less than or equal to 0.01 fmol/cm2 S, or less than or equal to 5 ions/disk-second across the disk membrane. Neither incubation in 10 mM Ca (which increases cytoplasmic activity 10--100- fold) nor photostimulation (which photoactivated up to 50% rhodopsin/h) had measurable effect on exchange rate, though an increase of several orders of magnitude would have been expected according to the hypothesis. The observed exchange could not be explained by: (a) 45Ca losses from disks before measurement (neither the net efflux nor the Ca- Ca exchange property of disks adequately explains such losses), (b) a limited pool of exchangeables Ca from strongly binding intradiskal sites, or (c) rate-limiting flux across the plasma membrane during incubation. For the study of the Ca efflux properties of disks, separate experiments were performed with 45Ca-loaded disks. Intradiskal activity could be estimated from the disks' hyperosmotically sensitive 45Ca pool and from their intradiskal volume (indirectly assayed by density). Ca-Ca exchange was undetectable (less than or equal to 0.1 fmol/cm2 S) in disks whose intradiskal activity was at least 0.3 mM. Net efflux was 0.2 fmol/cm2 S for an intradiskal activity of approximately 1 mM and is comparable to published fluxes for phospholipid vesicles. These results seem to exclude the internal space of disks as the source of Ca for photoreceptor excitation.     

Demonstration of oestrogen receptor in symptomatic breast carcinoma, using fine needle aspiration cytology

Oestrogen receptor immunocytochemical assay (ER-ICA) was used to determine oestrogen receptor (ER) content of cells in fine needle aspirate (FNA) specimens from 88 breast carcinomas. In 49 of these the radioligand binding assay for oestradiol was available for comparison. The predictive value of ER-ICA staining for a positive radioligand binding assay (greater than 10 fmol/mg protein) was 95%. Although the predictive value of negative staining was only 66%, 34 out of 37 ER-ICA negative tumours had radioligand binding assays below 60 fmol/mg protein. ER-ICA staining showed a strong positive correlation with age of the patient, positivity being rare before the menopause. There was a weak inverse correlation with tumour grade but none with tumour size or lymph node status. The assessment of ER by immunocytochemistry using FNA cytology is a rapid technique, which may easily be repeated and provides a pre-operative assessment of ER status. It allows confirmation that tumour cells are present in the sample and an assessment of tumour heterogeneity.     

Characterization of specific binding of atrial natriuretic peptide (ANP) to rat PC12 phaeochromocytoma cells

Specific binding sites for atrial natriuretic peptide have been identified in membrane of the phaeochromocytoma cell line PC12. Scatchard analysis of binding studies revealed a Kd of 794 pM and a density (Bmax) of 254 fmol/mg protein. Hormones unrelated to ANP such as angiotensin II, bradykinin and arginine-8-vasopressin did not complete for the binding sites. Of the ANP-related peptides which competed for the binding sites, the following order of affinity was established; rANP (8-33) greater than rANP (28 amino acid) greater than rat atrial peptide fragment (13-28) greater than a-hANP (28 amino acid) greater than atrial peptide fragment (1-11) greater than atriopeptin I.     

Airway reactivity to methacholine in nonatopic asymptomatic adults

We studied 50 nonsmoking volunteers, ages 18-35 yr, with no past or present history or physical examination findings of asthma, rhinitis, allergic disease, or recent respiratory infections, to evaluate the usefulness of the methacholine bronchoprovocation challenge (MBPC) as a screening test for asthma. All were skin-test-negative to 29 aeroallergens and had base-line pulmonary function values greater than 80% predicted. Fourteen (28%) subjects had a drop in forced expiratory volume in 1 s (FEV1) of 20% or greater at a provocative dose (PD20FEV1) less than or equal to 225 breath units. Moreover, when these subjects were compared with 21 asymptomatic allergic asthmatics, there was significant overlap between the two groups in concentration of methacholine causing this decline in FEV1. A positive MBPC at methacholine concentrations less than or equal to 5 mg/ml was not diagnostic of asthma, and a negative MBPC at methacholine concentrations greater than or equal to 10 mg/ml did not rule out asthma. These data strongly suggest that MBPC should not be used as the sole factor for the diagnosis of clinically significant asthma. A positive MBPC is one indication of the presence of airway hyperresponsiveness and thus is only one of many factors that must be considered in the diagnosis of asthma.     

Value of ER-D5 immunocytochemical determination in routine tissue sections of human breast cancer

ER-D5 is a recently identified protein related to estrogen receptors (ER). Generally ER measurement requires fresh frozen tissue and for ER-D5 assay ethanol (E) fixation of the specimen is recommended. We evaluated the possibility of immunocytochemical detection of ER-D5 in routine formalin-fixed (F) sections in 51 breast cancers comparing the results with those obtained in the same specimens using E as fixative. The results of ER-D5 assay were expressed by the staining index (SI) taking values greater than or equal to 5 as positive. In all tumors ER was also assayed by a biochemical method (DCCA). The sensitivity of ER-D5 detection in F was only 33.3%, while the specificity was 94.4%. A lower cut-off value of SI for F sections (greater than or equal to 2) increased the sensitivity to 66.6%, leaving the specificity unchanged. A strong correlation was found between the SI of ER-D5 in E and F (p less than 0.001). The SI of ER-D5 in F sections was also well correlated with ER concentrations (p less than 0.001). These results suggest that immunocytochemical determination of ER-D5 in routine sections may be useful in retrospective studies of hormone dependence in breast cancer.     

Effects of clomiphene citrate on the pituitary gland in chronically estrogenized rat

Effects of clomiphene citrate (clomiphene) on the pituitary gland of chronically estrogenized ovariectomized rats were investigated. Estradiol-17 beta (E2) pellet implanted subcutaneously in castrated rats for 7 days caused significant increases in pituitary weight and serum prolactin (PRL) level but suppressed serum luteinizing hormone (LH) level. In the estrogenized rats about 40% of estrogen receptor (ER) found in whole pituitary cells (65 +/- 7 fmol/10 mg tissue) was observed in the nucleus, while 60% of ER was present in the cytosol fraction. A single injection of 5 micrograms E2 translocated cytosol ER immediately to nuclear compartment; amounts of ER found in cytosol and nuclear fractions were 16 +/- 1 and 37 +/- 4 fmol/10 mg tissue, respectively, at 1 h. However, the distribution of ER returned to the pre-injection level within 4 h. In the non-estrogenized castrated rats, the nuclear retention of ER was significantly longer than that in the estrogenized rats. A single administration of 200 micrograms clomiphene in the estrogenized rats, on the other hand, increased nuclear ER gradually. Nuclear ER reached the peak level at 4 h (62 +/- 5 fmol/10 mg tissue) and the level remained almost unchanged for 24 h. Cytosol ER decreased and reached a nadir at 4 h (4.3 +/- 0.3 fmol), and the replenishment of cytosol ER could not be detected for 24 h. Similar patterns of cytosol and nuclear ER following the clomiphene injection were also found in the castrated rats. The clomiphene administration in the estrogenized rats resulted in a significant reduction of the pituitary weight 48 h after the administration. The present results seem to show the antiestrogenic action of clomiphene in the pituitary gland.     

Lipid screening: is it enough to measure total cholesterol concentration?

OBJECTIVES--To determine whether measurement of total cholesterol concentration is sufficient to identify most patients at lipoprotein mediated risk of coronary heart disease without measurement of triglyceride and high density lipoprotein (HDL) cholesterol concentrations. DESIGN--Cross sectional screening programme. SETTING--Six general practices in Oxfordshire. PATIENTS--1901 Men and 2068 women aged 25-59. MAIN OUTCOME MEASURE--Cardiovascular risk as assessed by fasting venous plasma concentrations of total cholesterol, triglyceride, and HDL cholesterol. RESULTS--2931 Patients (74% of those screened) had a total cholesterol concentration of less than 6.5 mmol/l. If the triglyceride concentration had not been measured in these patients isolated hypertriglyceridaemia (greater than or equal to 2.3 mmol/l) would have remained undetected in 185. Among these 185 patients, however, 123 were overweight or obese and only 18 (0.6% of those screened) had an increased risk associated with both a raised triglyceride concentration (greater than or equal to 2.3 mmol/l) and a low HDL cholesterol concentration (less than 0.9 mmol/l). Conversely, in the 790 patients with predominant hypercholesterolaemia (cholesterol concentration greater than or equal to 6.5 mmol/l and triglyceride concentration less than 2.3 mmol/l) measurement of HDL cholesterol concentration showed that 348 (9% of those screened) had only a moderately increased risk with a ratio of total to HDL cholesterol of less than 4.5 and 104 had a low risk with a ratio of less than 3.5. CONCLUSIONS--Fasting triglyceride and HDL cholesterol concentrations identify few patients at increased risk of coronary heart disease if the total cholesterol concentration is less than 6.5 mmol/l. HDL cholesterol and triglyceride concentrations should, however, be measured in patients with a total cholesterol concentration exceeding this value. Total cholesterol concentration alone may overestimate risk in a considerable number of these patients, and measurement of HDL cholesterol concentration allows a more precise estimate of risk. Measurement of the triglyceride concentration is required to characterise the lipoprotein abnormality. A patient should not be started on a drug that lowers lipid concentrations without having had a full lipoprotein assessment including measurement of HDL cholesterol concentration.