The Efficacy of Herbal Supplement Danggui Buxue Tang for Relieving Menopausal Symptoms.

OBJECTIVES: This study aimed to further explore the efficacy and safety of Danggui Buxue Tang (DBT), a simple herbal formula, for improving the quality of life of women suffering from menopausal symptoms. METHODS: A third clinical trial to determine the clinical efficacy of high-dose DBT for a period of 12 weeks was carried out. The standard Menopause-Specific Quality of Life (MENQOL) assessment chart was used for the evaluation. Safety was defined as an absence of direct estrogenic effects, serum inflammatory cytokines. Notably, interleukin IL-6, IL-8 and tumor necrosis factor TNF-α, known to be directly related to estrogenic reactions in menopause studies, were monitored. RESULTS: The third clinical trial indicated an overall improvement in the four domains of MENQOL, offering further proof of the efficacy of DBT demonstrated in the two previous trials. The serial checks of the three cytokines related to estrogen activities did not show either upward or downward trends. The haphazard behavior reactions of the three cytokines offered indirect indications that DBT improved the MENQOL independently from estrogen activities. CONCLUSIONS: The three clinical trials using DBT to relieve menopausal syndrome have offered solid evidence for its efficacy. The uncertainty regarding whether the "phytoestrogen" contained in DBT had bioactivities similar to estrogen was alleviated through the confirmation that no strict estrogenic bioactivities were observed. The issue of safety was further clarified via laboratory platform studies on DBT, which not only showed the lack of similarity with estrogen actions but also confirmed the value of combining the two herbs in the classic formula.

Magnetoelastic properties and behaviour of 4C pyrrhotite, Fe7S8, through the Besnus transition.

Pyrrhotite, Fe7S8, is a commonly occurring carrier of magnetic remanence and has a low temperature transition, the Besnus transition, involving a change in spin state. Variations of the thermodynamic, magnetic and elastic properties through this transition at ∼33 K in a natural sample of 4C pyrrhotite have been tested against a group theoretical model for coupling between order parameters relating to Fe/vacancy ordering (irrep U 1(1/2,0,1/4)) and magnetic ordering (irreps m[Formula: see text] and m[Formula: see text]). Magnetoelastic coupling is weak but the pre-existing microstructure of ferroelastic and magnetic domains, that develop as a consequence of Fe/vacancy and ferrimagnetic ordering during slow cooling in nature (P63/mmc → C2'/c'), causes subtle changes in the low temperature transition (C2'/c' → P [Formula: see text]). The Besnus transition involves a rotation of magnetic moments out of the a-c plane of the monoclinic structure, but it appears that the transition temperature might vary locally according to whether it is taking place within the pre-existing domain walls or in the domains that they separate. Evidence of metamagnetic transitions suggests that the magnetic field-temperature phase diagram will display some interesting diversity. Low temperature magnetic transitions in minerals of importance to the palaeomagnetism community have been used to identify the presence of magnetite and haematite in rocks and the Besnus transition is diagnostic of the existence of pyrrhotite, Fe7S8.

Magnetoelastic coupling associated with vacancy ordering and ferrimagnetism in natural pyrrhotite, Fe7S8.

Magnetoelastic coupling associated with the hexagonal-monoclinic transition in a natural sample of the mineral pyrrhotite, Fe7S8, has been analysed in terms of separate coupling of spontaneous strains with two discrete order parameters, q v for Fe/vacancy ordering and q m for magnetic ordering. Coupling of the two order parameters separately with strain gives rise to two terms for coupling between them, λ [Formula: see text] and λ [Formula: see text], and a pattern of evolution in which q v varies continuously and q m discontinuously through a single transition point. The transition is ferrimagnetic and ferroelastic but the relatively slow relaxation rate for Fe/vacancy ordering, in comparison with magnetic ordering, results in elastic and anelastic properties which are quite different from those observed in other ferroic or multiferroic materials with two instabilities. Instead of classical elastic softening, there is stiffening of the elastic constants which scales with [Formula: see text] and [Formula: see text]. Instead of the normal pattern of acoustic loss associated with the mobility and subsequent freezing for ferroelastic twin walls, the loss is consistently low throughout the temperature range 300 K-875 K.

Tuning dimensionality in van-der-Waals antiferromagnetic Mott insulators TMPS3.

We present an overview of our recent work in tuning and controlling the structural, magnetic and electronic dimensionality of 2D van-der-Waals antiferromagnetic compounds (Transition-Metal)PS3. Low-dimensional magnetic systems such as these provide rich opportunities for studying new physics and the evolution of established behaviours with changing dimensionality. These materials can be exfoliated to monolayer thickness and easily stacked and combined into functional heterostructures. Alternatively, the application of hydrostatic pressure can be used to controllably close the van-der-Waals interplanar gap and tune the crystal structure and electron exchange paths towards a 3D nature. We collect and discuss trends and contrasts in our data from electrical transport, Raman scattering and synchrotron x-ray measurements, as well as insight from theoretical calculations and other results from the literature. We discuss structural transitions with pressure common to all materials measured, and link these to Mott insulator-transitions in these compounds at high pressures. Key new results include magnetotransport and resistivity data in the high-pressure metallic states, which show potentially interesting qualities for a new direction of future work focussed on low temperature transport and quantum critical physics.

Dielectric Response of Quantum Critical Ferroelectric as a Function of Pressure.

In this work we report for the first time measurements of the dielectric loss of single-crystal SrTiO3 under the application of hydrostatic pressure up to 20 kbar and temperatures down to 200 mK which allow us to comment on the evolution of new fundamental material properties and their relationship with the recently discovered quantum critical phenomena in this material. The well known 18 K peak or shoulder was no longer observed after pressure was applied, even after subsequently removing it, suggesting it is associated with the twin walls formed at the 110 K cubic-tetragonal transition. The family of familiar peaks were all seen to increase in temperature linearly with pressure and the height of the 9.4 K peak was drastically suppressed by even the smallest pressures. This peak is discussed in the context of a postulated ferroelectric quantum critical point in SrTiO3 and the behaviour of its size linked to the position of this point on the recently established phase diagram.

Pressure-Induced Electronic and Structural Phase Evolution in the van der Waals Compound FePS_{3}.

Two-dimensional materials have proven to be a prolific breeding ground of new and unstudied forms of magnetism and unusual metallic states, particularly when tuned between their insulating and metallic phases. Here we present work on a new metal-to-insulator transition system FePS_{3}. This compound is a two-dimensional van der Waals antiferromagnetic Mott insulator. We report the discovery of an insulator-metal transition in FePS_{3}, as evidenced by x-ray diffraction and electrical transport measurements, using high pressure as a tuning parameter. Two structural phase transitions are observed in the x-ray diffraction data as a function of pressure, and resistivity measurements show evidence of the onset of a metallic state at high pressures. We propose models for the two new structures that can successfully explain the x-ray diffraction patterns.

STRETCHY ELECTRONICS. Hierarchically buckled sheath-core fibers for superelastic electronics, sensors, and muscles.

Superelastic conducting fibers with improved properties and functionalities are needed for diverse applications. Here we report the fabrication of highly stretchable (up to 1320%) sheath-core conducting fibers created by wrapping carbon nanotube sheets oriented in the fiber direction on stretched rubber fiber cores. The resulting structure exhibited distinct short- and long-period sheath buckling that occurred reversibly out of phase in the axial and belt directions, enabling a resistance change of less than 5% for a 1000% stretch. By including other rubber and carbon nanotube sheath layers, we demonstrated strain sensors generating an 860% capacitance change and electrically powered torsional muscles operating reversibly by a coupled tension-to-torsion actuation mechanism. Using theory, we quantitatively explain the complementary effects of an increase in muscle length and a large positive Poisson's ratio on torsional actuation and electronic properties.

Maca reduces blood pressure and depression, in a pilot study in postmenopausal women.

OBJECTIVE: Lepidium meyenii (Maca) has been used for centuries for its fertility-enhancing and aphrodisiac properties. In an Australian study, Maca improved anxiety and depressive scores. The effects of Maca on hormones, lipids, glucose, serum cytokines, blood pressure, menopausal symptoms and general well-being in Chinese postmenopausal women were evaluated. METHODS: A randomized, double-blind, placebo-controlled, cross-over study was conducted in 29 postmenopausal Hong Kong Chinese women. They received 3.3 g/day of Maca or placebo for 6 weeks each, in either order, over 12 weeks. At baseline, week 6 and week 12, estradiol, follicle stimulating hormone (FSH), sex hormone binding globulin (SHBG), thyroid stimulating hormone (TSH), full lipid profiles, glucose and serum cytokines were measured. The Greene Climacteric, SF-36 Version 2, Women's Health Questionnaire and Utian Quality of Life Scales were used to assess the severity of menopausal symptoms and health-related quality of life. RESULTS: There were no differences in estradiol, FSH, TSH, SHBG, glucose, lipid profiles and serum cytokines amongst those who received Maca as compared to the placebo group; however, significant decreases in diastolic blood pressure and depression were apparent after Maca treatment. CONCLUSIONS: Maca did not exert hormonal or immune biological action in the small cohort of patients studied; however, it appeared to reduce symptoms of depression and improve diastolic blood pressure in Chinese postmenopausal women. Although results are comparable to previous similar published studies in postmenopausal women, there might be a cultural difference among the Chinese postmenopausal women in terms of symptom reporting.

Global consensus statement on menopausal hormone therapy.

The following Consensus Statement is endorsed by The American Society for Reproductive Medicine, The Asia Pacific Menopause Federation, The Endocrine Society, The European Menopause and Andropause Society, The International Menopause Society, The International Osteoporosis Foundation and The North American Menopause Society.

Protein tyrosine kinase 7: a novel surface marker for human recent thymic emigrants with potential clinical utility.

Recent thymic emigrants (RTEs) are antigenically naive T cells that have recently completed intrathymic maturation and have emigrated from the thymus to the periphery. RTEs are clinically and immunologically important as they are essential for maintaining peripheral T cells in sufficient numbers in order to recognize, by their αßT-cell receptors (TCRs), a diverse array of foreign peptide antigens. However, RTE frequency and function has been poorly understood because of a lack of surface markers to distinguish them from older non-RTE naive T cells. This review summarizes the biology of the intrathymic generation and function of RTEs, including the recent identification of protein tyrosine kinase 7 (PTK7) as a novel marker for human RTEs of the CD4 (helper) T-cell lineage. PTK7+ RTEs in adults have a reduced capacity for activation-induced proliferation and cytokine production (interleukin-2 and interferon-γ) than older PTK7- naive CD4 T cells. Importantly, this immaturity in CD4 RTE effector function may contribute to the reduced adaptive immune responses observed in situations in which CD4 RTEs predominate, including the fetus, neonate and young infant, and following immune reconstitution, such as post-hematopoietic stem cell transplant. The ability to identify viable CD4+ RTEs based on PTK7 surface staining may be particularly useful in the infant for better defining the impact of nutritional and environmental factors on thymic output, peripheral T-cell function and adaptive immune responses to vaccination and infection.

Menopause management: a cardiovascular risk-based approach.

Hormone replacement therapy (HRT) remains the gold standard for the management of menopausal symptoms; however, HRT use has declined due to concerns over possible adverse side-effects. Approaches to menopause management are continually being revised and these extend beyond the control of recognized menopausal symptoms to encompass wider aspects of menopausal women's health. Hypertension and associated cardiovascular risk are particularly important unmet needs in postmenopausal women, especially in the Asia-Pacific region which has a rapidly aging population and bears around half of the global burden of cardiovascular disease, two-thirds of which has been attributed to elevated blood pressure. As first point of contact for women with menopausal symptoms, gynecologists play a gatekeeper role in assessing women's health, providing appropriate lifestyle counseling, and, where appropriate, implementing treatment or referral to relevant specialists. This paper, with contributions by gynecologists and cardiologists from Asia Pacific and beyond, summarizes available evidence and provides a treatment algorithm that employs a flexible blood pressure classification strategy to assist physicians in their decision-making for the individualized management of menopausal symptoms in women with low, moderate and high cardiovascular risk, and also for women with diabetes. Individualized HRT according to cardiovascular risk may yield improvements in cardiovascular health, as well as managing menopausal symptoms.

Three-dimensional ultrasound features of the polycystic ovary in Chinese women.

OBJECTIVES: To quantify the three-dimensional (3D) ultrasound characteristics of ovaries in Chinese women with polycystic ovarian syndrome (PCOS) and to compare these with previous data on a Caucasian cohort with PCOS. METHODS: 3D pelvic ultrasound was performed in 40 Chinese women with PCOS and 40 controls. Ovarian volume, stromal volume and echogenicity, and antral follicle count (AFC) were measured and ovarian blood flow was quantified using both 3D power Doppler and two-dimensional (2D) pulsed wave Doppler. These data were compared with previously published data on a Caucasian cohort with PCOS. RESULTS: Compared with controls, women with PCOS had a higher AFC (median (range), 15 (11-30) vs. 5.5 (1-10) per ovary, P < 0.01), ovarian volume (12.32 (8.10-16.16) mL vs. 5.64 (2.62-8.81) mL, P < 0.01) and stromal volume (9.74 (6.44-13.56) mL vs. 4.07 (1.52-6.67) mL, P < 0.01) but were comparable in stromal echogenicity and ovarian blood flow as measured by 3D power Doppler or 2D pulsed wave Doppler indices. However, in comparison with a previously reported Caucasian cohort with PCOS, the ovaries of Chinese women with PCOS had a significantly smaller stromal volume (median (range), 9.74 (6.44-13.56) mL vs. 10.79 (5.65-17.12) mL, P < 0.05), were less echogenic as reflected in a lower mean gray value (22.43 (13.13-35.50) vs. 32.36 (19.35-53.71), P < 0.01), and had reduced ovarian blood flow as reflected in a lower flow index (30.19 (23.32-44.88) vs. 33.54 (21.88-51.65), P < 0.05). CONCLUSION: Based on 3D ultrasound measurements, Chinese women with PCOS have an increased stromal volume compared with controls. However, their stromal volume, echogenicity and vascularity is significantly lower than that in Caucasian women with PCOS. The possible etiology for these differences is discussed.

Micro-dose transdermal estradiol for relief of hot flushes in postmenopausal Asian women: a randomized controlled trial.

OBJECTIVES: To compare the effect of micro-dose transdermal estradiol and placebo on the incidence and severity of menopausal symptoms and well-being in postmenopausal Asian women with vasomotor symptoms. DESIGN: Multicenter, double-blind, randomized, placebo-controlled study. RESULTS: Of 165 subjects randomized to estradiol 0.014 mg/day or placebo for 12 weeks, 80 per group were included in the analysis. Groups were comparable at baseline, although time since menopause was slightly shorter in the estradiol group. There was a greater reduction in mean weekly hot flushes at week 12 in the estradiol group (55%) than the placebo group (40%; p < 0.01), which was evident by week 4. A similar pattern was seen for moderate and severe hot flushes (-58% vs. -39%, respectively). Reductions were statistically significant at weeks 4, 8, and 12. Vaginal pH fell significantly in the estradiol group by week 4 and then remained stable throughout the treatment period, but there were no significant changes in the placebo group. Vaginal maturation value increased more in the estradiol than the placebo group (p < 0.001). Few subjects had vaginal bleeding or spotting. Quality of life improved similarly in both groups. Urogenital symptoms improved considerably from baseline in both treatment groups, with no significant differences. Eight subjects experienced treatment-related adverse events (seven in the estradiol group). CONCLUSIONS: In Asian women, micro-dose estradiol was significantly superior to placebo in improving vasomotor symptoms. The bleeding profile was comparable with that of placebo. Micro-dose estradiol was safe and well tolerated in Asian women.

Menopausal symptoms in mid-life women in southern China.

OBJECTIVES: To explore the prevalence of menopausal symptoms in Chinese women aged 40-65 years living in Guangdong province in southern China, and to investigate their care-seeking behavior. DESIGN: A cross-sectional population-based study performed in Guangdong province, PR China. METHODS: A total of 9939 women were selected by multistage cluster sampling. From November 2003 to July 2004, women were interviewed in person with a prepared questionnaire about symptoms experienced in the 2 months preceding the survey. The main outcome measurements were self-reported menopausal symptoms and related factors. RESULTS: The mean age of natural menopause was 48.9 years. The prevalence and severity of menopausal symptoms were low. The three most prevalent symptoms were insomnia, joint and muscle pain, and dizziness (in 37.2%, 35.7%, and 31.5% of the sample, respectively). Hot flushes were experienced by 17.5% of women. The factors associated with the frequency of menopausal symptoms included profession, education, type of menopause and the presence of physical or emotional problems. Ever and current hormone replacement therapy usage was reported in 0.8% and 1.3% of women, respectively. Of the total study population, 28.9% had sought health care because of menopausal symptoms. CONCLUSIONS: The prevalence of menopausal symptoms in southern Chinese women is low, and this is accompanied by low usage of hormone replacement therapy.

A randomized, double-blind, placebo-controlled study of the effect of a Chinese herbal medicine preparation (Dang Gui Buxue Tang) on menopausal symptoms in Hong Kong Chinese women.

OBJECTIVE: Many complementary or alternative medicines are being used for the treatment of menopausal symptoms but most have not been properly tested for efficacy or for safety. This study examined the effect of a Chinese herbal preparation (Dang Gui Buxue Tang) on menopausal symptoms in Hong Kong Chinese women. METHODS: A 6-month randomized, double-blind, placebo-controlled study of the effect of Dang Gui Buxue Tang (a 1 : 5 combination of Dang Gui (Angelicae sinensis) and Huang Qi (Astragalus membranaceus)) on acute menopausal symptoms. A total of 103 symptomatic women were enrolled. Three failed to meet inclusion criteria, leaving 50 subjects for inclusion in each group. RESULTS: Overall, mild hot flushes were reported more frequently than either moderate or severe flushes. In analysis by severity of flushes, there was a significant reduction in the number of mild hot flushes per month in the treatment group but not in the placebo group (from 18.9 +/- 23.5 at baseline to 8.6 +/- 17.1 at 6 months in the treatment group (p < 0.01) and from 26.0 +/- 43.5 to 12.4 +/- 17.6 in the placebo group (p = 0.062)). For moderate flushes, there was a significant reduction in the placebo group compared with the treatment group (from 18.9 +/- 28.7 at baseline to 11.1 +/- 29.9 at 6 months in the placebo group (p < 0.05) and from 10.5 +/- 22.3 to 6.0 +/- 16.0 in the treatment group (p = 0.107)). There was no significant change in either treatment or placebo groups in the reporting of severe hot flushes. Episodes of night sweats decreased significantly in the placebo but not in the treatment group (from 6.8 +/- 10.0 at baseline to 1.9 +/- 5.7 at 6 months in the placebo group (p < 0.05) and from 5.4 +/- 8.9 to 3.2 +/- 8.5 in the treatment group (p = 0.471)). In the vasomotor domain of the Menopause Specific Quality of Life, there was a significant reduction in scoring in the placebo group (from 2.8 +/- 1.6 to 1.7 +/- 1.3, p < 0.01) but not in the treatment group (from 2.8 +/- 2.1 to 2.3 +/- 1.6, p = 0.247). CONCLUSIONS: This study found overall no significant difference between Dang Gui Buxue Tang and placebo in the treatment of vasomotor symptoms in Hong Kong Chinese women. The frequency of mild, moderate and severe hot flushes decreased in both treatment and placebo groups, but Dang Gui Buxue Tang was statistically superior to placebo only in the treatment of mild hot flushes. There were no serious adverse events attributable to treatment during the study period.

Cardiovascular risks and metabolic syndrome in Hong Kong Chinese women with polycystic ovary syndrome.

BACKGROUND: Women with polycystic ovary syndrome (PCOS) frequently exhibit central obesity, glucose intolerance, atherogenic dyslipidaemia and hypertension which are characteristic features of the metabolic syndrome (MetS). METHODS: A total of 295 premenopausal Chinese women with PCOS diagnosed by the Rotterdam criteria (mean age: 30.2 +/- 6.4 years) and 98 control subjects without PCOS were evaluated for prevalence of MetS and cardiovascular risk factors, including dyslipidaemia and dysglycaemia. RESULTS: Using the 2005 modified Adult Treatment Panel III criteria, MetS (presence of three or more risk factors) was found in 24.9% of PCOS women compared to 3.1% of controls. The prevalence of MetS in PCOS women increased from 16.7% at under 30 years of age to 53.3% at over 40 years. MetS was also more prevalent in overweight and obese (41.3%) than normal-weight PCOS women (0.9%). However, multivariate regression analysis showed that women with PCOS had a 5-fold increase in risk of MetS (odds ratio 4.90; 95% confidence interval: 1.35-17.84) compared with women without PCOS even after controlling for age and BMI, suggesting PCOS alone is an independent risk factor for MetS. CONCLUSIONS: There is high prevalence of MetS in Hong Kong Chinese women with PCOS despite their relatively young age. Recognition of these cardiometabolic risk factors requires a high level of awareness in conjunction with early and regular screening.

Distinct lipid/lipoprotein profiles and hormonal responsiveness in nine ethnic groups of postmenopausal Asian women: the Pan-Asia Menopause (PAM) study.

BACKGROUND: Lipid/lipoprotein profiles, among other factors, are associated with risk of cardiovascular disease. Because cardiovascular disease varies in Asian countries, we hypothesized that lipid profiles differ in ethnic groups of postmenopausal Asian women. To add to the limited body of information currently available, we also investigated the effects of estrogen/progestin therapy on lipid/lipoprotein profiles in postmenopausal Asian women. METHODS: The Pan-Asia Menopause (PAM) study was a prospective, randomized, double-blind clinical trial evaluating 1028 postmenopausal women at 22 investigational centers in 11 Asian countries/territories. Subjects were randomly assigned to one of three doses of continuous combined conjugated estrogens (CE)/medroxyprogesterone acetate (MPA): CE/MPA (in mg/day) = 0.625/2.5, 0.45/1.5 or 0.3/1.5. The treatment period, following baseline evaluations, consisted of six continuous 28-day cycles. Analysis of lipid profiles was a secondary objective of the PAM study. Total cholesterol, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), very low density cholesterol (VLDC-C), triglycerides and lipoprotein(a) were analyzed at a central laboratory by state-of-the-art methods. RESULTS: Mean concentrations of total cholesterol, LDL-C, VLDL-C and triglycerides differed significantly among the nine ethnic groups of postmenopausal women. This difference was independent of body mass index and age, two factors that also influenced lipid/lipoprotein profiles. Mean HDL-C concentrations also differed, but this difference was influenced by body mass index in a weak interaction. All three doses of CE/MPA significantly lowered total cholesterol. Treatment with the high and middle doses significantly lowered LDL-C, and increased HDL-C, VLDL-C and triglycerides. The high dose produced a significant decrease in lipoprotein(a). CONCLUSIONS: The different lipid/lipoprotein profiles in the nine ethnic groups of postmenopausal Asian women evaluated here suggest a relationship to differences in the prevalence of cardiovascular disease reported for different regions in Asia. However, the reported prevalence data on cardiovascular disease morbidity and mortality in the regions corresponding to the nine ethnic groups are insufficient to allow qualitative comparisons with the lipid profiles shown in our study. The lipid/lipoprotein changes in response to estrogen/progestin therapy observed here are consistent with those reported for Western women.

Expression of a novel T-complex testis expressed 5 (Tctex5) in mouse testis, epididymis, and spermatozoa.

Expression of T-complex testis expressed 5 (Tctex5), an orthologue of protein phosphatase-1 inhibitor-3 (PPP1R11), was enhanced in mouse testis and was also expressed in epididymis and spermatozoa. There were three transcripts of Tctex5 including one brain specific and two common transcripts dominant in mouse testis. Tctex5 protein isoforms (75, 52, 32, 25, and 14.3 kDa) were identified. Isoforms of 75 and 52 kDa were spermatogenic-specific and were found in protein fraction containing nuclei, mitochondria, and flagellum accessory, and also in protein fraction containing mainly membranes. Tctex5 was localized in nuclei of pachytene spermatocytes, round spermatocytes, cytoplasm of Sertoli cells in testis; cilia, secretion bodies and nuclei of epithelial cells and interstitium smooth muscle cells in epididymis; and head and principal piece of tail in epididymal spermatozoa. The results suggested that Tctex5 might be a specific protein phosphatase-1 inhibitor in sperm; various Tctex5 transcripts and isoforms and cellular locations imply its different roles in spermatogenesis. Nuclei-type isoforms (75 and 52 kDa) might take part in nucleus remodeling during spermatogenesis whilst membrane-type isoform (52 kDa) might be responsible for dephosphorylation of proteins during capacitation. The other isoforms might play general roles for all kinds of cell types.

Comparison between phytoestrogens and estradiol in the prevention of atheroma in ovariectomized cholesterol-fed rabbits.

OBJECTIVES: There is increasing interest in the role of complementary and alternative medicines for the treatment of menopause-related problems. This study compared the preventive effect on atheroma formation of a commercially available mixed phytoestrogen concentrate with that of estradiol. METHODS: An ovariectomized cholesterol-fed rabbit model of atheroma formation was used. Rabbits were ovariectomized before the commencement of the 12-week treatment period. There were two control groups. Control Group 1 received isoflavone-free rabbit chow whilst Control Group 2 received 1% cholesterol-enriched isoflavone-free rabbit chow. Rabbits in Group 3 received 1% cholesterol-enriched isoflavone-free rabbit chow plus a 500 mg tablet containing a concentrated extract of Trifolium pretense (red clover). Rabbits in Group 4 received 1% cholesterol-enriched isoflavone-free rabbit chow plus a 0.5 mg tablet of oral estradiol. Atheroma formation was measured by, first, calculation of the area of atheroma on the intimal surface, and, second, measuring the cholesterol content in the aorta. RESULTS: There were no significant differences in serum cholesterol between the cholesterol-fed control Group 2 and the treatment Groups 3 and 4. However, there was significantly less staining for atheroma and significantly less cholesterol accumulation in the aorta in Group 4 (estradiol-treated) rabbits compared with either control Group 2 or Group 3 (phytoestrogen-treated) rabbits. CONCLUSION: In this study, only estradiol was shown to have a significant protective effect against atheroma formation.