Phytochemical characterization and antidiabetic analysis of Bauhinia holophylla extract on the maternal-fetal outcomes of rats.

This study aims to evaluate the phytochemical properties of Bauhinia holophylla (Bong.) Steud leaf extract, and their impact on maternal reproductive and fetal development in diabetic rats. For this, adult female Wistar rats (100 days of life) received streptozotocin (40 mg/Kg, intraperitoneal) for induction of diabetes, were mated and distributed into four groups: Nondiabetic; Nondiabetic given B. holophylla; Diabetic; and Diabetic given B. holophylla. The plant extract was given by gavage at increasing doses: 200, 400, and 800 mg/Kg. At day 21 of pregnancy, liver and blood samples were obtained for oxidative parameters and biochemical analysis, respectively. The uterus was removed for maternal-fetal outcomes. Phytochemical analysis showed a high content of phenolic components and biogenic amines. B. holophylla extract did not alter the glycemic levels but improved the lipid profile in diabetic animals. Besides that, the number of live fetuses and maternal weight gain were decreased in Diabetic group, and were not observed in animals treated. The group Diabetic treated presented a higher percentage of fetuses classified as adequate for gestational age compared to the Diabetic group. However, the treatment with plant extract caused embryo losses, fetal growth restriction, and teratogenicity in nondiabetic rats. Thus, the indiscriminate consumption requires carefulness.

Analysis of Risk Factors for a Low Immune Response to Messenger RNA COVID-19 Vaccine in Kidney Transplant Recipients and Differences Between Second and Third Dose.

BACKGROUND: The efficacy of the response to SARS-CoV-2 vaccination in kidney transplant recipients is low. The aim of our study was to evaluate the risk factors correlated with the low antibody response and whether there was an improvement between the second and the third dose. METHODS: A prospective study was conducted on 176 kidney transplant recipients who received the second and the third dose of the anti-SARS-CoV-2 mRNA Comirnaty vaccine. We evaluated the seroconversion process after administration of the second and the third dose and assessed a possible correlation with age, time between transplant and vaccination, and type of immunosuppressive therapy. RESULTS: A total of 98 of the 176 patients (55.7%) responded positively after the inoculation of the second dose and according to the multivariable logistic regression analysis the lack of seroconversion was independently associated with patient age ≥60 (P = .025; odds ratio [OR], 2.094), time since transplant of 1 to 3 months (P = .032; OR, 2.118), and triple therapy (P = .044; OR, 2.327). After the vaccine third dose, the seroconversion increased to 62.5%, and it was negatively influenced by calcineurin inhibitor use (12/21, 57.1% vs 71/78, 91.0%, P = .0006) and triple therapy (13/21, 61.9% vs 72/78, 92.3%, P = .0014). The median of antispike antibody response significantly increased from 18.5 IU/mL after the second dose to 316.9 IU after the third dose (P < .0001). CONCLUSIONS: We demonstrated a correlation between older age and shorter distance from the transplant and triple immunosuppressive therapy with the lack of seroconversion. We noticed a significant improvement in antibody response by a third dose of messenger RNA vaccine.

Gender, lifestyles, illness perception and stress in stable atrial fibrillation.

AIMS: The study is aimed at investigating if perceived stress in Stable Atrial Fibrillation (AF) has any gender-associated feature and relationships with lifestyle indicators and education level, and which relationship self efficacy, anxiety and depression and illness perception have, if any. PATIENTS AND METHODS: 88 consecutive patients referred for stable AF are studied by Psychological Stress Measure (PSM) test, Illness Perception Questionnaire (IPQ-R), Generalized Self-Efficacy scale (GSE) and Hospital Anxiety and Depression Scale (HADS). Mediterranean diet, physical activity increase and smoking withdrawal counseling were provided. RESULTS: AF patients have higher PSM associated with gender (women), older age, anxiety and depression. Higher GSE, greater Adherence to Mediterranean Diet profile and coffee habits (greater coffee users) are associated with a reduced hazard of perceived stress. By multiple linear regression, PSM is explained by Anxiety and IPQr (statistically significant are emotional representation and illness coherence subscales), which account for 92.2% of the variance (p<0.0001). CONCLUSION: Our results outline that psychological stress is greater in women in comparison with men. Illness perceptions are important in the context of perceived stress in AF. This effect appears to be modulated by greater self-efficacy and by Adherence to Mediterranean Diet profile, that when higher, are associated with a reduced hazard of perceived stress. We suggest that therapeutic interventions on illness perceptions can be warranted in order to achieve a lower psychological distress in AF patients.

Stress, abdominal obesity and intrarenal resistive index in essential hypertension.

AIM: Although it is commonly believed that a strong causal link exists between psychological stress and hypertension, as well with other factors, such as obesity, just what kind of empirical evidence supports this assumption is still controversial. The aim of the study is to investigate if perceived stress have any interference with intrarenal resistance and hence with mechanisms related to Essential Hypertension (EH) and if Anxiety, Depression, Self efficacy and Illness Perception can account for perceived stress. PATIENTS AND METHODS: Obesity, insulin resistance (HOMA), Doppler Renal Resistive Index (RRI) and glomerular filtration rate (GFR) are studied along with Psychological Stress Measure (PSM), Illness Perception Questionnaire (IPQ-R), Generalized Self-Efficacy scale (GSE) and Hospital Anxiety and Depression Scale (HADS) in 119 hypertensive patients referred for stable lasting EH, and 150 normal controls. Lower salt/lower calories Mediterranean diet, physical activity increase and smoking withdrawal counseling were provided. RESULTS: By Odds Ratios, higher risk of EH is associated with greater perceived stress, older age, lower GFR, obesity, greater RRI and insulin resistance. By Multiple Linear Regression the most significant variable that accounts for higher RRI are abdominal obesity and arterial pulse pressure; the only significant independent psychological variable that accounts for abdominal obesity are PSM and identity IPQ subscale. Self-Efficacy anxiety and Illness perception subscales (IPQr), accounts significantly for 62.0% of the variance to PSM, with possible effects on RRI and on the pathophysiological hypertension cascade. CONCLUSION: Worst identity and treatment control perceptions of EH, and a lower self-efficacy are the main psychological factors accounting for a greater stress. Interventions aimed to reduce perceived stress can be warranted in EH.

Pain assessment in fibromyalgia and rheumatoid arthritis: influence of physical activity and illness perception.

OBJECTIVE: Pain visual analog scales (VAS) have been validated for clinical use in fibromyalgia (FM) and rheumatoid arthritis (RA) patients. There are potential limitations, however, not only considering their use as a continuous measurement, but also with regard to the influence of personal illness perceptions, habitual physical activity and other life-style features. The aim of the study was to ascertain whether different illness perception, physical activity and clinical and laboratory characteristics can predict the severity of perceived pain assessed by VAS. MATERIALS AND METHODS: This is an observational comparative study of forty consecutive out-patients, 20 of them with fibromyalgia and 20 with rheumatoid arthritis, treated by medical and physical therapy. Patients were assessed also by Pain VAS, Health Assessment Questionnaire (HAQ) disability index, Ritchie index, Baecke questionnaire for physical activity, Illness Perception Questionnaire (IPQr) and SF36. RESULTS: Pain VAS is explained differently by some of the studied variables: in the total group HAQ and Ritchie index explain 29.8% of the variance; in the RA patients number of joints with pain and Ritchie index explain 52.7% of the variance; in FM patients total SF36 score and IPQr personal control dimension explains 44.7% of the variance. No definite role of anxiety and/or depression was found as predictor of perceived pain and disability. CONCLUSION: Pain perception and complaint are explained by belief in FM patients: This seems to suggest the need for a more articulated cognitive approach; addressing both diagnostic and therapeutic interventions to anxiety/depression issues is not supported by our results.

Analysis of changes in optical fibers during arc-fusion splicing by use of quantitative phase imaging.

A non-interferometric imaging technique in conjunction with Abel inversion is used to directly and quantitatively examine the changes in optical fibers due to the heating produced during arc-fusion splicing as a function of fusion arc parameters. Phase images in the vicinity of a fusion splice are obtained using Quantitative Phase Microscopy, allowing the refractive-index change to be reconstructed with high spatial resolution. This simple, nondestructive method confirms that, for a fixed arc current, while the fusion time increases, the refractive-index of both fiber cores within the fusion region decreases in magnitude, the core region broadens, and the axial gradient decreases.

Evaluation of a primary care-oriented brief counselling intervention for obesity with and without orlistat.

OBJECTIVE: There is a significant need for an obesity treatment model suitable for the primary care environment. We examined the effectiveness of a brief counselling intervention alone, in combination with orlistat, and drug-alone in a 12-month randomized-clinical trial at a medical school obesity centre. METHODS: Participants (N = 250) with body mass index (BMI) >or=27 were randomized. Changes in body weight, lipids, blood pressure and serum glucose were examined. Drug adherence and attendance were also evaluated. RESULTS: Completers analysis was conducted on 136 participants with data at baseline, 6 and 12 months and intention-to-treat analyses (ITT) for the total sample. Amongst completers, participants in the drug only (P = 0.012) and drug + brief counselling (P = 0.001) groups lost more weight (mean +/- SD: -3.8 +/- 5.8 kg and -4.8 +/- 4.4 kg, respectively) than participants in the brief counselling only group at 6 months (-1.7 +/- 3.3 kg), but there were no significant group differences at 12 months. ITT model results were similar to completers at 6 months and remained significant at 12 months, but the weight losses were more modest (<3 kg) for both groups receiving orlistat. For brief counselling alone, participants gained weight (1.7 +/- 4.2 kg). Cardiovascular disease (CVD) parameter changes were negligible. CONCLUSIONS: Pharmacotherapy alone or combined with brief counselling resulted in modest weight losses that had minimal impact on cardiovascular parameters, but were greater than brief counselling alone. Whilst brief interventions and primary pharmacotherapy have been suggested as viable treatments for implementation in primary care settings, our study suggests that such minimal interventions provide minimal benefits.

Weight loss with meal replacement and meal replacement plus snacks: a randomized trial.

OBJECTIVE: To evaluate whether snacking would improve weight loss and weight maintenance in overweight individuals within the context of a structured meal replacement (MR) weight loss program. DESIGN: A prospective 24 week, 2 (snacking vs nonsnacking) x 2 (MR vs meal replacement augmented with snacks (MRPS)) randomized trial. Participants were instructed to limit their total daily intake to 1200 (women) or 1500 (men) kcals. Those receiving the MR program were instructed not to snack while those in the MRPS program were told to snack three times per day. SUBJECTS: A total of 100 participants were block-randomized, based on prestudy snacking status (high vs low), to receive a standard meal replacement program (MR) or MRPS. MEASUREMENTS: Weight, height, blood pressure, lipid fractions, glucose, and insulin were assessed at the baseline, 12-, and 24 weeks. RESULTS: Completers analysis at 24 weeks demonstrated a significant time effect (F(1,46)=44.6, P<0.001), indicating that all participants lost significant amounts of weight regardless of group assignment. An intention-to-treat model resulted in similar results. By week 24, the average weight loss across groups was 4.6 kg. There also were significant improvements across all groups among completers for systolic blood pressure (P=0.047), cholesterol (P=0.001), LDL (P=0.001), glucose (P=0.004), and insulin (P=0.001) at week 12, and glucose (P=0.001) and insulin at week 24 (P=0.003). CONCLUSIONS: Our results suggest that a participant's preferences for snacking did not affect their response to treatment. Snackers and nonsnackers responded equally well whether they received a standard meal replacement program or one augmented with snacks.

Gliotoxin is a dual inhibitor of farnesyltransferase and geranylgeranyltransferase I with antitumor activity against breast cancer in vivo.

Gliotoxin is a natural mycotoxin with immunosuppressive and antimicrobial activity. Inhibition of farnesyltransferase (IC50 80 microM) and geranylgeranyltransferase I (IC50 17 microM) stimulated interest in the potential antitumor activity of this epidithiodioxopiperazine. Gliotoxin inhibited proliferation of six breast cancer cell lines in culture with mean +/- SD IC50 289 +/- 328 microM (range 38-985 microM); intracellular farnesylation of Lamin B and geranylgeranylation of Rap1A were inhibited in a dose-dependent manner. In randomized controlled studies using the N-methyl-N-nitrosourea rat mammary carcinoma model, gliotoxin had pronounced antitumor activity in vitro and little systemic toxicity when administered to 10 animals at 10 mg/kg by subcutaneous injection weekly for 4 wk compared with 10 controls. Single doses up to 25 mg/kg were well tolerated. The present studies confirm that gliotoxin is a dual inhibitor of farnesyltransferase and geranylgeranyltransferase I with pronounced antitumor activity and favorable toxicity profile against breast cancer in vitro and in vivo.

Refractive index profiles of Ge-doped optical fibers with nanometer spatial resolution using atomic force microscopy.

We show a quantitative connection between Refractive Index Profiles (RIP) and measurements made by an Atomic Force Microscope (AFM). Germanium doped fibers were chemically etched in hydrofluoric acid solution (HF) and the wet etching characteristics of germanium were studied using an AFM. The AFM profiles were compared to both a concentration profile of the preform determined using a Scanning Electron Microscope (SEM) and a RIP of the fiber measured using a commercial profiling instrument, and were found to be in excellent agreement. It is now possible to calculate the RIP of a germanium doped fiber directly from an AFM profile.

Trichostatin A is a histone deacetylase inhibitor with potent antitumor activity against breast cancer in vivo.

PURPOSE: Trichostatin A (TSA), an antifungal antibiotic with cytostatic and differentiating properties in mammalian cell culture, is a potent and specific inhibitor of histone deacetylase (HDAC) activity. The purpose of this study was to evaluate the antiproliferative and HDAC inhibitory activity of TSA in vitro in human breast cancer cell lines and to assess its antitumor efficacy and toxicity in vivo in a carcinogen-induced rat mammary cancer model. EXPERIMENTAL DESIGN AND RESULTS: TSA inhibited proliferation of eight breast carcinoma cell lines with mean +/- SD IC(50) of 124.4 +/- 120.4 nM (range, 26.4-308.1 nM). HDAC inhibitory activity of TSA was similar in all cell lines with mean +/- SD IC(50) of 2.4 +/- 0.5 nM (range, 1.5-2.9 nM), and TSA treatment resulted in pronounced histone H4 hyperacetylation. In randomized controlled efficacy studies using the N-methyl-N-nitrosourea carcinogen-induced rat mammary carcinoma model, TSA had pronounced antitumor activity in vivo when administered to 16 animals at a dose of 500 microg/kg by s.c. injection daily for 4 weeks compared with 14 control animals. Furthermore, TSA did not cause any measurable toxicity in doses of up to 5 mg/kg by s.c. injection. Forty-one tumors from 26 animals were examined by histology. Six tumors from 3 rats treated with TSA and 14 tumors from 9 control animals were adenocarcinomas. In contrast, 19 tumors from 12 TSA-treated rats had a benign phenotype, either fibroadenoma or tubular adenoma, suggesting that the antitumor activity of TSA may be attributable to induction of differentiation. Two control rats each had tumors with benign histology. CONCLUSIONS: The present studies confirm the potent dose-dependent antitumor activity of TSA against breast cancer in vitro and in vivo, strongly supporting HDAC as a molecular target for anticancer therapy in breast cancer.

Analysis of estrogen-responsive finger protein expression in benign and malignant human breast.

The estrogen-responsive finger protein (EFP) gene was originally identified in a screen of genomic DNA for genes containing estrogen-response elements (EREs), and its expression was subsequently shown to be estrogen-regulated and correlated with estrogen receptor (ER)alpha-positive tissues in mice. Human chromosomal mapping localized it to 17q23.1, close to BRCA1, in a region frequently lost in breast cancers. Structurally related proteins have been implicated in a variety of important cellular processes, including carcinogenisis. Given that ER is over-expressed in a large proportion of breast cancers, we reasoned that EFP may play a role in mediating the estrogen-dependent progression of breast cancer. We raised anti-sera to EFP and show that EFP is present in the cytoplasm in mammary cell lines and epithelial cells of normal breast tissue. Furthermore, EFP is present in cell culture medium, suggesting that it may be secreted. Immunohistochemistry of paraffin-embedded breast biopsy specimens showed significantly greater levels of EFP in lactating breast and fibroadenomata compared to normal breast (p<0.001 and p = 0.001, respectively), which is likely to be a result of estrogen responsiveness. Levels were reduced in breast cancer (p = 0.02), where no correlation was seen with other immunohistochemical, histopathological or clinical data. The lack of correlation between EFP and ER status of tumors could indicate escape from estrogenic control, pointing to new models of tumor pathogenesis. Increased levels of EFP in lactating breast and the reduction in malignancy suggest a role for EFP in promoting mammary gland differentiation.

Activation of estrogen receptor alpha by S118 phosphorylation involves a ligand-dependent interaction with TFIIH and participation of CDK7.

Phosphorylation of the estrogen receptor alpha (ERalpha) N-terminal transcription activation function AF1 at serine 118 (S118) modulates its activity. We show here that human ERalpha is phosphorylated by the TFIIH cyclin-dependent kinase in a ligand-dependent manner. Furthermore, the efficient phosphorylation of S118 requires a ligand-regulated interaction of TFIIH with AF2, the activation function located in the ligand binding domain (LBD) of ERalpha. This interaction involves (1) the integrity of helix 12 of the LBD/AF2 and (2) p62 and XPD, two subunits of the core TFIIH. These findings are suggestive of a novel mechanism by which nuclear receptor activity can be regulated by ligand-dependent recruitment of modifying activities, such as kinases.

Supercritical fluid extraction and solid-phase extraction of AC 263, 222 and imazethapyr from three Texas soils.

Supercritical fluid extraction (SFE) using CO(2) and solid-phase extraction (SPE) are two technologies recently discussed in the literature as alternatives to Soxhlet and liquid/liquid extraction (LLE). This research compared SFE and SPE extraction efficiency of two imidazolinone herbicides, AC263,222 and imazethapyr, from three soils. Recovery of the herbicides using SFE-CO(2) with a 4.6:1 acetonitrile:acetic acid cosolvent was approximately 80% for Poth and Tremona soils and 60% when extracted from Ships soil with high clay content and high pH. SPE recovery of both herbicides averaged 78% and was not statistically different between soils. Combining SPE disks with a SPE cartridge cleanup procedure provided a faster filtration with cleaner filtrate compared with using SPE C-18 cartridges by themselves. Cleanup was needed after both SFE and SPE disk extraction due to interfering peaks in the chromatography. http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p440.html

Phosphorylation of human estrogen receptor alpha by protein kinase A regulates dimerization.

Phosphorylation provides an important mechanism by which transcription factor activity is regulated. Estrogen receptor alpha (ERalpha) is phosphorylated on multiple sites, and stimulation of a number of growth factor receptors and/or protein kinases leads to ligand-independent and/or synergistic increase in transcriptional activation by ERalpha in the presence of estrogen. Here we show that ERalpha is phosphorylated by protein kinase A (PKA) on serine-236 within the DNA binding domain. Mutation of serine-236 to glutamic acid prevents DNA binding by inhibiting dimerization by ERalpha, whereas mutation to alanine has little effect on DNA binding or dimerization. Furthermore, PKA overexpression or activation of endogenous PKA inhibits dimerization in the absence of ligand. This inhibition is overcome by the addition of 17beta-estradiol or the partial agonist 4-hydroxy tamoxifen. Interestingly, treatment with the complete antagonist ICI 182,780 does not overcome the inhibitory effect of PKA activation. Our results indicate that in the absence of ligand ERalpha forms dimers through interaction between DNA binding domains and that dimerization mediated by the ligand binding domain only occurs upon ligand binding but that the complete antagonist ICI 182,780 prevents dimerization through the ligand-binding domain. Heterodimer formation between ERalpha and ERbeta is similarly affected by PKA phosphorylation of serine 236 of ERalpha. However, 4-hydroxytamoxifen is unable to overcome inhibition of dimerization by PKA. Thus, phosphorylation of ERalpha in the DNA binding domain provides a mechanism by which dimerization and thereby DNA binding by the estrogen receptor is regulated.

An important role for BRCA1 in breast cancer progression is indicated by its loss in a large proportion of non-familial breast cancers.

The presence of BRCA1 protein was determined immunohistochemically in normal and benign breast biopsies, non-familial breast carcinomas and breast carcinomas from one or more individuals from 8 BRCA1 families. Strikingly, little staining was detected in breast carcinomas from BRCA1 families, regardless of the position or type of mutation, whereas strong immunostaining was observed in 28/28 of non-malignant breast biopsies. Furthermore, BRCA1 staining was reduced in non-familial breast carcinomas, since loss of nuclear BRCA1 staining was evident in 19% of non-familial breast carcinomas whilst a similar proportion (20%) showed absence of either cytoplasmic or nuclear BRCA1 staining. Statistical analysis indicates that breast cancer is characterised by a reduction in levels of nuclear BRCA1 in familial (p < 0.001) and non-familial breast cancer (p = 0.001). In non-familial breast cancer absence of nuclear BRCA1, but not cytoplasmic BRCA1, is more common in high grade breast carcinomas (p = 0.03) and in patients with evidence of lymph node involvement (p = 0.05). Correlation between the absence of BRCA1 protein with high grade is consistent with previous findings of a correlation between mutations in the BRCA1 gene and high grade. Our findings provide new evidence in support of BRCA1 as a tumour suppressor protein in non-familial breast cancer.

Human estrogen receptor beta binds DNA in a manner similar to and dimerizes with estrogen receptor alpha.

The cloning of a novel estrogen receptor beta (denoted ERbeta) has recently been described (Kuiper, G. G. J. M., Enmark, E., Pelto-Huikko, M., Nilsson, S., and Gustafsson, J-A. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 5925-5930 and Mosselman, S., Polman, J. , and Dijkema, R. (1996) FEBS Lett. 392, 49-53). ERbeta is highly homologous to the "classical" estrogen receptor alpha (here referred to as ERalpha), has been shown to bind estrogens with an affinity similar to that of ERalpha, and activates expression of reporter genes containing estrogen response elements in an estrogen-dependent manner. Here we describe functional studies comparing the DNA binding abilities of human ERalpha and beta in gel shift assays. We show that DNA binding by ERalpha and beta are similarly affected by elevated temperature in the absence of ligand or in the presence of 17beta-estradiol and the partial estrogen agonist 4-hydroxy-tamoxifen. In the absence of ligand, DNA binding by ERalpha and beta is rapidly lost at 37 degrees C, while in the presence of 17beta-estradiol and 4-hydroxy-tamoxifen, the loss in DNA binding at elevated temperature is much more gradual. We show that the loss in DNA binding is not due to degradation of the receptor proteins. However, while the complete antagonist ICI 182, 780 does not "protect" human ERalpha (hERalpha) from loss of DNA binding at elevated temperature in vitro, it does appear to protect human ERbeta (hERbeta), suggestive of differences in the way ICI 182, 780 acts on hERalpha and beta. We further report that ERalpha and beta can dimerize with each other, the DNA binding domain of hERalpha being sufficient for dimerization with hERbeta. Cell and promoter-specific transcription activation by ERalpha has been shown to be dependent on the differential action of the N- and C-terminal transcription activation functions AF-1 and AF-2, respectively. The existence of a second estrogen receptor gene and the dimerization of ERalpha and beta add greater levels of complexity to transcription activation in response to estrogens.

Presence of exon 5-deleted oestrogen receptor in human breast cancer: functional analysis and clinical significance.

A variant form of the human oestrogen receptor (ER) mRNA lacking sequences encoded within exon 5 has been described (Fuqua SAW, Fitzgerald SD, Chamness GC, Tandon AK, McDonnell DP, Nawaz Z, O'Malloy BW, McGuire WL 1991, Cancer Res 51: 105-109). We have examined the expression of the exon 5-deleted ER (HE delta5) mRNA variant in breast biopsies using reverse transcriptase polymerase chain reaction (RT - PCR). HE delta5 mRNA was present in only 13% of non-malignant breast tissues compared with 32% of carcinomas (95% CI, P=0.05). Presence of the HE delta5 mRNA was associated with the presence of immunohistochemically detected ER (P=0.015) and progesterone receptor (PR) (P=0.02). There was a positive correlation between the presence of HE delta5 and disease-free survival (P=0.05), suggesting that the presence of HE delta5 may be an indicator of better prognosis. We have raised a monoclonal antibody specific to the C-terminal amino acids of HE delta5. This antibody recognized the variant but not the wild-type ER protein. We show that HE delta5 protein is present in breast cancer using immunohistochemical techniques. We also analysed trans-activation by HE delta5 in mammalian cells and showed that, in MCF-7 cells, HE delta5 competes with wild-type ER to inhibit ERE-dependent trans-activation. Our results indicate that this variant is unlikely to be responsible for endocrine resistance of breast cancer, but its presence at both the mRNA and protein level suggest that it may, nevertheless, be involved in regulating the expression of oestrogen-responsive genes in breast cancer.

Idoxifene is equipotent to tamoxifen in inhibiting mammary carcinogenesis but forms lower levels of hepatic DNA adducts.

Tamoxifen is an effective agent preventing mammary carcinogenesis in rats but causing liver tumours. Idoxifene is a more potent antioestrogen and is effective in patients with advanced breast cancer. We therefore compared the effects of idoxifene with tamoxifen on mammary carcinogenesis and hepatic DNA adduct formation. To do this, we undertook a study designed to compare tamoxifen with idoxifene as a chemopreventive agent in rats inoculated with N-methylnitrosourea (MNU) and also measured hepatic adduct formation. We examined the time to mammary tumour development in 272 female Ludwig/Wistar/Olac rats treated with MNU followed by tamoxifen (5 mg kg(-1)), equimolar idoxifene or vehicle three times a week for up to 24 weeks. To determine duration of effect, a second study was carried out whereby all of the 129 animals surviving at the end of treatment were entered into a surveillance programme for 27 weeks after the end of the administration period. Hepatic DNA adduct formation was examined by 32P-postlabelling in a group of rats after 24 weeks' treatment. In the first study, both idoxifene and tamoxifen were effective in preventing tumour growth as only 2 out of 21 (10%) MNU and vehicle-treated animals were alive and tumour free after 24 weeks compared with 13 out of 22 (59%) animals receiving MNU followed by idoxifene or tamoxifen (P < 0.001). The second study showed that, in both idoxifene- and tamoxifen-treated animals, a progressive regrowth of tumours occurred after cessation of therapy, as by the end of the observation period only four idoxifene-treated animals and one tamoxifen-treated animal were free from disease. In the subset of animals tested, tamoxifen-treated animals had approximately 100 times higher levels of DNA hepatic adducts than idoxifene-treated animals. Adducts were not seen in the control group. These results indicate that idoxifene is as effective a chemopreventive agent as tamoxifen in the rat while causing only very low levels of DNA adducts in liver tissue and suggest that idoxifene may be a well-tolerated chemopreventive agent in women who are at increased risk of breast cancer.

Annual variability in methacholine responsiveness in nonasthmatic working adults.

Change in airway responsiveness is used frequently as a clinical as well as an epidemiological tool. Changes in airway responsiveness can be superior to other measures of lung function in that they are more sensitive indicators of an environmental effect. However, normal variation in test results must be defined before change can be interpreted. To characterize annual variability in airways responsiveness, we administered a high-dose methacholine challenge at 1 yr intervals for up to 4 yrs to 105 healthy, nonasthmatic working subjects. Using this high-dose protocol, the majority of tests (83%) produced at least a 20 % fall in forced expiratory volume in one second (FEV1), allowing standard calculation of the provocative dose of methacholine causing a 20% fall in FEV1 (PD20). An annual change in methacholine responsiveness by one or more doubling doses was seen in at least 30% of subjects each year. The components of variance of airways responsiveness measures were estimated to allow direct comparison of within-subject and between-subject variability. The within-subject variability in PD20, was markedly greater than the comparable within-subject variability in FEV1. Level of FEV1 and age were both significant determinants of methacholine responsiveness. Comparison of two methods of expressing methacholine responsiveness (PD20 using the full challenge up to 250 mg x mL(-1) methacholine, and the dose-response slope using data up to 32 mg x mL(-1) methacholine as the maximum dose) had similar annual variability in censored data and mixed-effects models. We then developed an approach to statistical analysis of "right-censored" methacholine challenge data using a maximum likelihood estimation under a censored Gaussian model. These studies of methacholine responsiveness provide normative data on annual test variability in healthy, nonasthmatic working adults, and show that a shorter low-dose challenge has comparable annual variability to a lengthier high-dose challenge.