Influences on the dietary intakes of preschool children: a systematic scoping review.

BACKGROUND: Better diet quality of preschool children is associated with many important health outcomes, but there is significant room for improvement in many children's dietary intakes. The determinants of children's dietary intakes are complex and whole systems approaches may be effective tools for changing dietary intake. Collation of all the evidence available on determinants of preschool children's dietary intake is necessary to 'map' the whole system of influence. Therefore, this systematic scoping review of available literature on determinants of dietary intakes in preschool children was undertaken. METHODS: The Joanna Briggs Institute methods for conducting a systematic scoping review were followed. Articles published since 2000 which assessed influences on the dietary intakes of preschool children were identified, yielding a total of 246 papers. Studies of children with clinical conditions (excluding obesity), or those conducted in middle and low-income countries were excluded, due to the different systems of influence in these populations. Data were extracted and information synthesised based on ecological level (child, parent, household, childcare, or wider determinants). RESULTS: Most articles focused on influences at the parental level (n = 118, 48%), followed by those at the child level (n = 73, 30%). Most of the studies were of cross-sectional design (n = 109, 44%). Whilst many studies considered influences at multiple ecological levels (n = 63, 26%) few analyses determined interactions between factors in their relationship with children's dietary intakes, which is needed going forward using systems methods. CONCLUSION: A wealth of evidence exists examining influences on the dietary intakes of preschool children and this information would benefit from analysis using a systems thinking approach in order to assess effective levers for intervention and what works, for whom, under what circumstances.

Point-of-care Hepatitis C virus testing and linkage to treatment in an Australian inner-city emergency department.

BACKGROUND: In Australia, Hepatitis C Virus (HCV) treatment is declining, despite broad access to direct-acting antiviral medication. People who inject drugs are proportionally over-represented in emergency department presentations. Emergency department assessment of people who have injected drugs for HCV presents an opportunity to engage this marginalised population with treatment. We describe the outcomes of risk-based screening and point-of-care anti-HCV testing for emergency department patients, and linkage to outpatient antiviral treatment. METHODS: During the three-month study period, consecutive adult patients who presented to the emergency department during the study times were screened for risk factors and offered the OraQuick oral HCV antibody test. Those with reactive results were offered venepuncture in the emergency department for confirmatory testing and direct-acting antiviral treatment in clinic. The main outcome measures were the number and proportion of viremic participants that were linked to the hepatitis clinic, commenced treatment and achieved a sustained viral response. Secondary outcome measures were the proportion (%) of presentations screened that were oral antibody reactive, and the prevalence and type of HCV risk factors. RESULTS: During the study period, 2408 of the 3931 (61%) presentations to the emergency department were eligible for screening. Of these 2408 patients, 1122 (47%) participated, 307 (13%) declined participation and 977 (41%) could not be approached during their time in the emergency department. Among the 1122 participants, 378 (34%) reported at least one risk factor. Subsequently, 368 (97%) of the 378 participants underwent OraQuick anti-HCV test, and 50 (14%) had a reactive result. A risk factor of ever having injected drugs was present in 44 (88%) of participants who were sero-positive. Of the 45 that had blood tested, 30 (67%) were HCV ribonucleic acid (RNA) positive. Three participants died. Of the 27 remaining participants, 10 (37%) commenced treatment and 7 of these 10 (70%) obtained a cure. There was a high rate of homelessness (24%) among anti-HCV positive participants. CONCLUSION: Among emergency department participants with a risk factor for HCV, positive serology was common using a rapid point-of-care test. A history of injecting drug use was identified as the risk factor with highest yield for positive HCV serology, and is suitable as a single screening question. However, linkage to care post ED presentation was low in this marginalised population. There is a need for new pathways to improve the care cascade for marginalised individuals living with HCV infection.

The relationship between maternal self-efficacy, compliance and outcome in a trial of vitamin D supplementation in pregnancy.

In a randomised controlled trial of vitamin D during pregnancy, we demonstrated that women with lower self-efficacy were more likely to experience practical problems with taking the trial medication and that this was associated with lower compliance and achieved 25(OH)-vitamin D concentrations. INTRODUCTION: The relationship between self-efficacy (the belief that one can carry out a behaviour), compliance with study protocol and outcome was explored within a randomised, double-blind, placebo-controlled trial of vitamin D supplementation in pregnancy. METHODS: In the Maternal Vitamin D Osteoporosis Study (MAVIDOS) trial, women with circulating plasma 25(OH)-vitamin D of 25-100 nmol/l in early pregnancy were randomised to either 1000 IU cholecalciferol/day or matched placebo from 14 weeks until delivery. Circulating 25(OH)-vitamin D concentrations were assessed at 14 and 34 weeks' gestation. A sequential sub-sample completed Schwarzer's General Self-Efficacy Scale at 14 and 34 weeks and the Problematic Experiences of Therapy Scale at 34 weeks. Women were interviewed about their experiences of the trial and interview transcripts analysed thematically. RESULTS: In 203 women, those with higher self-efficacy were less likely to experience practical problems taking the study medication (odds ratio (OR) 0.81 (95 % confidence interval (CI) 0.69-0.95), p = 0.01). Over half reported practical problems associated with poorer compliance with the protocol requiring women to take the medication daily. Compliance in women who experienced practical problems was 94 % compared with 98 % for those with no problems (p < 0.001). Poorer compliance was also associated with lower concentrations of 25(OH)-D in late pregnancy in the treatment group (ß = 0.54 nmol/l (95 % CI 0.18-0.89), p = 0.003). Thematic analysis suggested common difficulties were remembering to take the medication every day and swallowing the large capsules. CONCLUSIONS: These findings suggest that differences in self-efficacy influence trial outcomes. Such information may help clinicians anticipate responses to routine vitamin D supplementation in pregnancy and identify those who may need more support to comply. TRIAL REGISTRATION: ISRCTN82927713, registered 11/04/2008.

Low levels of food involvement and negative affect reduce the quality of diet in women of lower educational attainment.

BACKGROUND: Women of lower educational attainment tend to have poorer quality diets and lower food involvement (an indicator of the priority given to food) than women of higher educational attainment. The present study reports a study of the role of food involvement in the relationship between educational attainment and quality of diet in young women. METHODS: The first phase uses six focus group discussions (n = 28) to explore the function of food involvement in shaping the food choices of women of lower and higher educational attainment with young children. The second phase is a survey that examines the relationship between educational attainment and quality of diet in women, and explores the role of mediating factors identified by the focus group discussions. RESULTS: The focus groups suggested that lower food involvement in women of lower educational attainment might be associated with negative affect (i.e. an observable expression of negative emotion), and that this might mean that they did not place a high priority on eating a good quality diet. In support of this hypothesis, the survey of 1010 UK women found that 14% of the effect of educational attainment on food involvement was mediated through the woman's affect (P ≤ 0.001), and that 9% of the effect of educational attainment on quality of diet was mediated through food involvement (P ≤ 0.001). CONCLUSIONS: Women who leave school with fewer qualifications may have poorer quality diets than women with more qualifications because they tend to have a lower level of food involvement, partly attributed to a more negative affect. Interventions to improve women's mood may benefit their quality of diet.

Hormonal impact of the 17alpha-hydroxylase/C(17,20)-lyase inhibitor abiraterone acetate (CB7630) in patients with prostate cancer.

A series of three dose escalating studies were conducted to investigate the ability of the 17alpha-hydroxylase/C(17,20)-lyase inhibitor abiraterone acetate, to cause maximum suppression of testosterone synthesis when delivered to castrate and noncastrate males with prostate cancer. Study A was a single dose study in castrate males. Study B was a single dose study in noncastrate males and study C was a multiple dose study in noncastrate males. The drug was given orally in a once-daily dose and blood samples taken to assess pharmacokinetic (PK) parameters and hormone levels in all patients. The study drug was well tolerated with some variability in PKs. Suppression of testosterone levels to <0.14 nmol l(-1) was seen in four out of six castrate males treated with a single dose of 500 mg. At 800 mg given days 1-12 in noncastrate males, target suppression was achieved in three out of three patients, but a two- to three-fold increase of Luteinising Hormone (LH) levels in two out of three patients overcame suppression within 3 days. All patients in the multiple dose study developed an abnormal response to a short Synacthen test by day 11, although baseline cortisol levels remained normal. This is the first report of the use of a specific 17alpha-hydroxylase/(17,20)-lyase inhibitor in humans. Repeated treatment of men with intact gonadal function with abiraterone acetate at a dose of 800 mg can successfully suppress testosterone levels to the castrate range. However, this level of suppression may not be sustained in all patients due to compensatory hypersecretion of LH. The enhanced testosterone suppression achieved in castrate men merits further clinical study as a second-line hormonal treatment for prostate cancer. Adrenocortical suppression may necessitate concomitant administration of replacement glucocorticoid.

A cancer research (UK) randomized phase II study of idoxifene in patients with locally advanced/metastatic breast cancer resistant to tamoxifen.

Idoxifene is a novel selective oestrogen receptor modulator (SERM) which had greater binding affinity for the oestrogen receptor (ER) and reduced agonist activity compared with tamoxifen in preclinical studies. In a randomized phase II trial in 56 postmenopausal patients with progressive locally advanced/metastatic breast cancer we assessed whether idoxifene showed evidence of activity compared with an increased 40 mg/day dose of tamoxifen in patients who had previously demonstrated resistance to the standard 20 mg/day dose of tamoxifen. Of 47 patients eligible for response (25 idoxifene, 22 tamoxifen), two partial responses and two disease stabilizations (SD) for >6 months were seen with idoxifene (overall clinical benefit rate 16%, 95% CI 4.5-36.1%). The median duration of clinical benefit was 9.8 months. In contrast, no objective responses were seen with the increased 40 mg/day dose of tamoxifen, although two patients had SD for 7 and 14 months (clinical benefit rate 9%, 95% CI 1.1-29.2%). Idoxifene was well tolerated and the reported possible drug-related toxicities were similar in frequency to those with tamoxifen (hot flushes 13% vs 15%, mild nausea 20% vs 15%). Endocrine and lipid analysis in both groups showed a similar significant fall in serum follicle-stimulating hormone and luteinizing hormone after 4 weeks, together with a significant rise in sex hormone binding globulin levels and 11% reduction in serum cholesterol levels. In conclusion, while idoxifene was associated with only modest evidence of clinical activity in patients with tamoxifen-resistant breast cancer, its toxicity profile and effects on endocrine/lipid parameters were similar to those of tamoxifen.

Synthesis of certain 2'-deoxyuridine derivatives containing substituted phenoxy groups attached to C-5'; evaluation as potential dUTP analogues.

Derivatives of 2'-deoxyuridine in which the 5'-OH group is replaced by a 2,3,6-trifluoro-5-hydroxy-4-nitrophenoxy or a 4-carboxy-2,3,6-trifluoro-5-hydroxyphenoxy group have been prepared for evaluation as possible dUTP analogues. They showed a weak ability to displace radiolabelled dUTP from a dUTP-binding antiserum. The corresponding compounds lacking the three fluorine substituents were prepared for comparison.

Adult female Drosophila pseudoobscura survive and carry fertile sperm through long periods in the cold: populations are unlikely to suffer substantial bottlenecks in overwintering.

To assess whether, while overwintering, natural populations of Drosophila pseudoobscura are likely to experience substantial bottlenecks in their numbers and genotypes, laboratory tests of the cold sensitivities of each stage of the life history and reproduction were undertaken. Three genetically distinctive lineages established from flies caught at high elevation were used for testing in temperatures likely to persist in protected pockets of fermenting deciduous leaf fall in overwintering sites. Sensitivities to cold of each stage in development were measured as frequencies of survival to adulthood following a period in 5 degrees C in a particular stage. The cold sensitivity of adults was measured as the survival in and following cold stays in adulthood. It was found that cold sensitivity decreases as development progresses, but that only adults (females more than males) are able to withstand long periods in the cold. The cold sensitivity of reproductive capacity of males was scored as their success in mating following a two-month cold stay, and of females as the numbers laying fertile eggs following periods of months in the cold. Both males and females maintain reproductive capacity. Of particular significance, however, is that even after six months in the cold females are able to restart production of eggs and these eggs may be fertilized by the sperm of matings prior to their cold stay. Thus, a substantial proportion of overwintering genomes must be those of adult females and those of the sperm carried by females from matings in the previous summer. This simple finding strongly suggests that populations are not likely to suffer substantial bottlenecks while overwintering. Further, it indicates how arrays of genetic variation may be maintained through winters and largely avoid winter selective pressures. Frequent migration between populations is therefore not required to maintain the variation commonly found in populations throughout the species range.

Unequal distribution of cognitive deficits in vascular dementia--is this a valid criterion in the ICD-10?

OBJECTIVE: To investigate the appropriateness of the ICD-10 criterion for vascular dementia which requires unequal distribution of deficits between different domains of cognitive function. DESIGN: Cross-sectional comparative study. SETTING: Referrals to a specialist memory clinic in Sheffield and a community sample of patients from a general practice population in Melton Mowbray. METHOD: The CAMCOG part of the Cambridge mental disorders of the elderly examination (CAMDEX) was assessed for 131 Sheffield subjects and 396 Melton Mowbray subjects to examine both total variability and differences between individual subscale items. Depression was also examined as this was a potential confounding factor. RESULTS: After adjustment for age, sex and depression scores, there were no significant differences between vascular dementia subjects and Alzheimer's disease subjects at either centre for total variability of cognitive deficits and little difference between diagnoses for individual subscale items. In Sheffield, subjects with vascular dementia had significantly higher depression scores compared to those with Alzheimer's disease. CONCLUSIONS: The usefulness of the concept of unequal deficits as a diagnostic criterion for vascular dementia in routine clinical practice is doubtful.

Evaluating recovery from anorexia nervosa and bulimia nervosa: integrating lessons learned from research and clinical practice.

The aims of this article are to critically examine the conceptualization and measurement of recovery, within the eating disorder outcome literature, and suggest possible ways of developing the clinical utility of outcome research. First, definitions and measures of recovery operationalized in outcome studies are critically reviewed, highlighting the variety of definitions and measures used in outcome research. Two important caveats in the outcome literature are identified: absence of clients' views on their recovery from outcome evaluations and dissociation of outcome research from negotiated interpersonal and organizational meanings of recovery. These caveats form the focus of the second section of the article. A need for greater integration between research and clinical perspectives on recovery is identified, and the final section of the article suggests several proposals for enhancing current research on recovery from eating disorders. These proposals particularly advocate development of methods and measures that can accommodate diversity of clients' experiences of recovery, while remaining informative to both researchers and clinicians.

Idoxifene antagonizes estradiol-dependent MCF-7 breast cancer xenograft growth through sustained induction of apoptosis.

Idoxifene is a novel selective estrogen (E2) receptor (ER) modulator that is currently in clinical development for the treatment of breast cancer. Compared to tamoxifen, idoxifene is metabolically more stable, with a higher relative binding affinity for the ER and reduced agonist activity on breast and uterine cells. Idoxifene also inhibits calmodulin, a calcium-binding protein that is involved in cell signal transduction pathways. In this study, the abilities of idoxifene and tamoxifen to antagonize E2-dependent MCF-7 xenograft growth in oophorectomized athymic mice were compared. The basis for idoxifene's antitumor activity was examined by comparing the effectiveness of the clinically used transisomer (referred to here as idoxifene) with its cis-isomer, which has a 50-fold lower relative binding affinity for ER than idoxifene but similar calmodulin-inhibitory activity. Changes in tumor cell proliferation, apoptosis, and ER-dependent protein expression were studied. Both idoxifene and tamoxifen significantly inhibited E2-dependent tumor growth, whereas cis-idoxifene had little effect. Withdrawal of E2 support induced significant tumor regression due to impaired cell proliferation (Ki-67 score, 9 versus 51% compared to E2 controls) and induction of apoptosis (3.6 versus 0.9% compared to E2 controls). Both anti-E2s inhibited cell proliferation and caused a significant 3-fold induction of apoptosis in E2 supported tumors after 1 week, which was maintained for 3 months with idoxifene (3.1 versus 0.48% compared to E2 controls) but decreased back to baseline in tumors treated with tamoxifen (0.69%). In contrast, cis-idoxifene had no effect on either cell proliferation or apoptosis. Both tamoxifen and idoxifene initially induced ER expression, whereas prolonged therapy with tamoxifen significantly reduced progesterone receptor levels. In conclusion, idoxifene resulted in similar inhibition of E2-dependent MCF-7 xenograft growth compared with tamoxifen, an effect that is mediated via ER rather than through calmodulin. Sustained induction of apoptosis may contribute to prolonged antagonism of E2-dependent growth, and it occurred to a greater extent following 3 months of idoxifene, compared to tamoxifen.

Solid-phase synthesis of novel inhibitors of farnesyl transferase.

A novel diphosphate mimic, the 2,3,6-trifluoro-5-hydroxy-4-nitrophenoxy group (1), has been employed as the template in the solid-phase synthesis of novel farnesyl transferase inhibitors using the Mitsunobu reaction. The most potent inhibitor (farnesyloxy-5-hydroxy-2,3,6-trifluoro-4-nitrobenzene) displayed an IC50 of 6.3 microM versus farnesyl transferase.

Inhibition of protein prenylation by metabolites of limonene.

The monoterpenes limonene and perillyl alcohol are undergoing clinical evaluation in cancer patients. In this paper, we report the chemical synthesis, characterisation, and quantitation in patients' plasma of a novel human metabolite of limonene, which is identified as an isomer of perillic acid. The synthesis of R-perillic acid is also described, because previous reports on the activity of perillic acid against isoprenylation enzymes refer to the S-enantiomer, although it is the R-enantiomer which is the metabolite of R-limonene. The above monoterpenes, with several related compounds, were assayed for inhibitory activity towards the isoprenylation enzymes in rat brain cytosol. Although R- and S-limonene are only weak inhibitors of the isoprenylation enzymes, their major metabolites, perillic acid and perillyl alcohol, are more potent inhibitors, with IC50 values in the low mM range. The metabolites possess greater activity towards the geranylgeranyltransferase type I enzyme than farnesyltransferase, while the novel metabolite displays IC50 values similar to those of perillic acid suggesting that it may contribute to the in vivo activity of limonene.

Inhibitory effect of simvastatin on the proliferation of human myeloid leukaemia cells in severe combined immunodeficient (SCID) mice.

SCID mice were inoculated intravenously with cells from the human HL60 myeloblastic leukaemia cell line and then treated with the 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor, simvastatin, by subcutaneous continuous infusion. The effect of the drug was measured by subsequent colony formation of surviving HL60 cells in vitro and flow cytometry. The number of clonogenic HL60 cells was reduced in the bone marrow of mice that received simvastatin compared with control mice by 65% and 68% in two separate experiments. The number of clonogenic, normal, murine, bone marrow progenitor cells concomitantly exposed to simvastatin in vivo, was not affected in either experiment. Flow cytometric analysis of bone marrow and spleen cells confirmed these results by showing that simvastatin had reduced the percentage of human leukaemia cells in these tissues by 70% and 88% respectively. The data show that the reported selective effect of simvastatin against acute myeloid leukaemia cells in vitro, can be extended to this in vivo model. HL60 bears an N-ras mutation. In further in vitro studies, ketoconazole, an inhibitor of cholesterol biosynthesis post farnesyl pyrophosphate synthesis, had a similar effect to simvastatin on HL60 colony development. Furthermore, the clonogenicity of a population of N-ras mutated, primary acute myeloid leukaemia (AML) cells was no more sensitive to simvastatin than a population without the mutation. The data suggest that the inhibition of AML cell proliferation by simvastatin may be independent of the RAS signalling pathway.

Tamoxifen induces selective membrane association of protein kinase C epsilon in MCF-7 human breast cancer cells.

Tamoxifen, a synthetic antiestrogen, is known for its antitumoral action in vivo; however, it is well accepted that many tamoxifen effects are elicited via estrogen receptor-independent routes. Previously, we reported that tamoxifen induces PKC translocation in fibroblasts. In the present study, we investigated the influence of tamoxifen, and several triphenylethylene derivatives, on protein kinase C (PKC) in MCF-7 human breast cancer cells. As measured by Western blot analysis, tamoxifen elicited isozyme-specific membrane association of PKC-epsilon, which was time-dependent (as early as 5 min post-treatment) and dose-dependent (5.0-20 microM). Tamoxifen did not influence translocation of alpha, beta, gamma, delta or zeta PKC isoforms. Structure-activity relationship studies demonstrated chemical requirements for PKC-epsilon translocation, with tamoxifen, 3-OH-tamoxifen and clomiphene being active. Compounds without the basic amino side chain, such as triphenylethylene, or minus a phenyl group, such as N,N-dimethyl-2-[(4-phenylmethyl)phenoxy]ethanamine, were not active. In vitro cell growth assays showed a correlation between agent-induced PKC-epsilon translocation and inhibition of cell growth. Exposure of cells to clomiphene resulted in apoptosis. Since PKC-epsilon has been associated with cell differentiation and cellular growth-related processes, the antiproliferative influence of tamoxifen on MCF-7 cells may be related to the interaction with PKC-epsilon.

Phase I and pharmacokinetic study of D-limonene in patients with advanced cancer. Cancer Research Campaign Phase I/II Clinical Trials Committee.

PURPOSE: D-Limonene is a natural monoterpene with pronounced chemotherapeutic activity and minimal toxicity in preclinical studies. A phase I clinical trial to assess toxicity, the maximum tolerated dose (MTD) and pharmacokinetics in patients with advanced cancer was followed by a limited phase II evaluation in breast cancer. METHODS: A group of 32 patients with refractory solid tumors completed 99 courses of D-limonene 0.5 to 12 g/m2 per day administered orally in 21-day cycles. Pharmacokinetics were analyzed by liquid chromatography-mass spectrometry. Ten additional breast cancer patients received 15 cycles of D-limonene at 8 g/m2 per day. Intratumoral monoterpene levels were measured in two patients. RESULTS: The MTD was 8 g/m2 per day; nausea, vomiting and diarrhea were dose limiting. One partial response in a breast cancer patient on 8 g/m2 per day was maintained for 11 months; three patients with colorectal carcinoma had prolonged stable disease. There were no responses in the phase II study. Peak plasma concentration (Cmax) for D-limonene ranged from 10.8+/-6.7 to 20.5+/-11.2 microM. Predominant circulating metabolites were perillic acid (Cmax 20.7+/-13.2 to 71+/-29.3 microM), dihydroperillic acid (Cmax 16.6+/-7.9 to 28.1+/-3.1 microM), limonene-1,2-diol (Cmax 10.1+/-8 to 20.7+/-8.6 microM), uroterpenol (Cmax 14.3+/-1.5 to 45.1+/-1.8 microM), and an isomer of perillic acid. Both isomers of perillic acid, and cis and trans isomers of dihydroperillic acid were in urine hydrolysates. Intratumoral levels of D-limonene and uroterpenol exceeded the corresponding plasma levels. Other metabolites were trace constituents in tissue. CONCLUSIONS: D-Limonene is well tolerated in cancer patients at doses which may have clinical activity. The favorable toxicity profile supports further clinical evaluation.

Synthesis and DNA reactivity of alpha-hydroxylated metabolites of nonsteroidal antiestrogens.

Tamoxifen [(E)-1-(4-(2-(N,N-dimethylamino)ethoxy)phenyl)-1, 2-diphenylbut-1-ene], a nonsteroidal antiestrogen, induces liver tumors in rats by a genotoxic mechanism. The mechanism of DNA adduct formation is believed to proceed via the formation of a reactive carbocation at the alpha-position from the alpha-hydroxylated metabolite. Molecular mechanics calculations [Kuramochi, H. (1996) J. Med. Chem. 39, 2877-2886] have predicted that 4-substitution will affect the stability of the carbocation and thus will alter its reactivity toward DNA. We have synthesized the putative alpha-hydroxylated metabolites of 4-hydroxytamoxifen [(E)-1-(4-(2-(N, N-dimethylamino)ethoxy)phenyl)-1-(4-hydroxyphenyl)-3-hydroxy-2-phenyl but-1-ene] and idoxifene [(Z)-1-(4-iodophenyl)-3-hydroxy-2-phenyl-1-(4-(2-(N-pyrrolidino) ethoxy)phenyl)but-1-ene] and compared their reactivities with DNA with that of alpha-hydroxytamoxifen [(E)-1-(4-(2-(N, N-dimethylamino)ethoxy)phenyl)-3-hydroxy-1,2-diphenylbut-1-ene]. As predicted, the bis-hydroxylated compound reacted with DNA in aqueous solution at pH 5 to give 12-fold greater levels of adducts than alpha-hydroxytamoxifen, whereas alpha-hydroxyidoxifene gave one-half the number of adducts. The results demonstrate that idoxifene presents a significantly lower genotoxic hazard than tamoxifen for the treatment and prophylaxis of breast cancer.

Length increase of the side chain of idoxifene does not improve its antagonistic potency in breast-cancer cell lines.

Linkage of specific residues onto steroidal estrogens through a long aliphatic side chain leads to "pure antiestrogens" devoid of residual estrogenic activity. Therefore, we assessed whether an increase in the length of the side chain of the triphenylethylenic antiestrogen idoxifene might increase its antagonistic potency. Culture of MCF-7 and tamoxifen-resistant variant RTX6 cells in the presence of CB 7675, a (CH2)8 derivative of idoxifene [(CH2)2], ruled out this possibility. This compound partly blocked MCF-7 cell growth only at 10(-6) M to almost the same extent as tamoxifen and failed to inhibit the growth of RTX6 cells, whereas the pure antiestrogen RU 58 668 was effective on both cell lines at much lower concentration. This absence of improvement was reflected in the observation of an efficiency for down-regulating progesterone receptor no better than that of tamoxifen. Pure antiestrogens are known to down-regulate the estrogen receptor, whereas triphenylethylenic antiestrogens up-regulate the receptor; CB 7675 behaves as the latter in agreement with its lack of strong antagonistic activity.