Vitalism, Holism, and Metaphorical Dynamics of Hans Spemann's "Organizer" in the Interwar Period.

This paper aims to provide a fresh historical perspective on the debates on vitalism and holism in Germany by analyzing the work of the zoologist Hans Spemann (1869-1941) in the interwar period. Following up previous historical studies, it takes the controversial question about Spemann's affinity to vitalistic approaches as a starting point. The focus is on Spemann's holistic research style, and on the shifting meanings of Spemann's concept of an organizer. It is argued that the organizer concept unfolded multiple layers of meanings (biological, philosophical, and popular) during the 1920s and early 1930s. A detailed analysis of the metaphorical dynamics in Spemann's writings sheds light on the subtle vitalistic connotations of his experimental work. How Spemann's work was received by contemporary scientists and philosophers is analyzed briefly, and Spemann's holism is explored in the broader historical context of the various issues about reductionism and holism and related methodological questions that were so prominently discussed not only in Germany in the 1920s.

From Organismic Biology as History and Philosophy to the History and Philosophy of Biology-the Work of Hans-Jörg Rheinberger in the German Context.

In this paper, I ask about the broader context of the history and philosophy of biology in the German-speaking world as the place in which Hans-Jörg Rheinberger began his work. Three German philosophical traditions-neo-Kantianism, phenomenology, and Lebensphilosophie-were interested in the developments and conceptual challenges of the life sciences in the late nineteenth and early twentieth centuries. Their reflections were taken up by life scientists under the terms theoretische Biologie (theoretical biology) and allgemeine Biologie (general biology), i. e., for theoretical and methodological reflections. They used historical and philosophical perspectives to develop vitalistic, organicist, or holistic approaches to life. In my paper, I argue that the resulting discourse did not come to an end in 1945. Increasingly detached from biological research, it formed an important context for the formation of the field of history and philosophy of biology. In Rheinberger's work, we can see the "Spalten" and "Fugen"-the continuities and discontinuities-that this tradition left there.

[Recent advances of synthetic biology for production of functional ingredients in Chinese materia medica].

The functional ingredients in Chinese materia medica are the main active substance for traditional Chinese medicine and most of them are secondary metabolites derivatives. Until now,the main method to obtain those functional ingredients is through direct extraction from the Chinese materia medica. However, the income is very low because of the high extraction costs and the decreased medicinal plants. Synthetic biology technology, as a new and microbial approach, can be able to carry out large-scale production of functional ingredients and greatly ease the shortage of traditional Chinese medicine ingredients. This review mainly focused on the recent advances in synthetic biology for the functional ingredients production.

Cell sensitivity, non-linearity and inverse effects.

It has been claimed that the homeopathic principle of 'similarity' (or 'similia') and the use of individualized remedies in extremely low doses conflicts with scientific laws, but this opinion can be disputed on the basis of recent scientific advances. Several mechanisms to explain the responsiveness of cells to ultra-low doses and the similarity as inversion of drug effects, have again been suggested in the framework of hormesis and modern paradoxical pharmacology. Low doses or high dilutions of a drug interact only with the enhanced sensitivities of regulatory systems, functioning as minute harmful stimuli to trigger specific compensatory healing reactions. Here we review hypotheses about homeopathic drug action at cellular and molecular levels, and present a new conceptual model of the principle of similarity based on allosteric drug action. While many common drugs act through orthostatic chemical interactions aimed at blocking undesired activities of enzymes or receptors, allosteric interactions are associated with dynamic conformational changes and functional transitions in target proteins, which enhance or inhibit specific cellular actions in normal or disease states. The concept of allostery and the way it controls physiological activities can be broadened to include diluted/dynamized compounds, and may constitute a working hypothesis for the study of molecular mechanisms underlying the inversion of drug effects.

From high dilutions to digital biology: the physical nature of the biological signal.

The memory of water was a radical idea that arose in the laboratory of Jacques Benveniste in the late 1980s. Twenty-five years have passed and yet the often angry debate on its merits continues despite the increasing number of scientists who have reported confirmation of the basic results. One working hypothesis was that molecules can communicate with each other, exchanging information without being in physical contact and that at least some biological functions can be mimicked by certain energetic modes characteristics of a given molecule. These considerations informed exploratory research which led to the speculation that biological signaling might be transmissible by electromagnetic means. Around 1991, the transfer of specific molecular signals to sensitive biological systems was achieved using an amplifier and electromagnetic coils. In 1995, a more sophisticated procedure was established to record, digitize and replay these signals using a multimedia computer. From a physical and chemical perspective, these experiments pose a riddle, since it is not clear what mechanism can sustain such 'water memory' of the exposure to molecular signals. From a biological perspective, the puzzle is what nature of imprinted effect (water structure) can impact biological function. A parallel can be drawn between this debate on the memory of water, which presumes that the action of molecules is mediated by an electromagnetic phenomenon, and the often acrimonious debate on the transmission of nerve influxes via synaptic transfer of specific molecules, neurotransmitters. The latter debate began in 1921 with the first experiments by Loewi and was still active in 1949, 28 years later. A strong reluctance to accept research that questions basic aspects of long-accepted biochemical paradigms is to be expected. In this paper we will provide a brief summary of experiments relating to the memory of water: the earlier work on high dilutions (HD) and then the experiments, which followed and continue today, on digital biology.

High-dilution effects revisited. 1. Physicochemical aspects.

Several lines of evidence suggest that homeopathic high dilutions (HDs) can effectively have a pharmacological action, and so cannot be considered merely placebos. However, until now there has been no unified explanation for these observations within the dominant paradigm of the dose-response effect. Here the possible scenarios for the physicochemical nature of HDs are reviewed. A number of theoretical and experimental approaches, including quantum physics, conductometric and spectroscopic measurements, thermoluminescence, and model simulations investigated the peculiar features of diluted/succussed solutions. The heterogeneous composition of water could be affected by interactive phenomena such as coherence, epitaxy and formation of colloidal nanobubbles containing gaseous inclusions of oxygen, nitrogen, carbon dioxide, silica and, possibly, the original material of the remedy. It is likely that the molecules of active substance act as nucleation centres, amplifying the formation of supramolecular structures and imparting order to the solvent. Three major models for how this happens are currently being investigated: the water clusters or clathrates, the coherent domains postulated by quantum electrodynamics, and the formation of nanoparticles from the original solute plus solvent components. Other theoretical approaches based on quantum entanglement and on fractal-type self-organization of water clusters are more speculative and hypothetical. The problem of the physicochemical nature of HDs is still far from to be clarified but current evidence strongly supports the notion that the structuring of water and its solutes at the nanoscale can play a key role.

High-dilution effects revisited. 2. Pharmacodynamic mechanisms.

The pharmacodynamics aspects of homeopathic remedies are appraised by laboratory studies on the biological effects at various levels (cellular, molecular and systemic). The major question is how these medicines may work in the body. The possible answers concern the identification of biological targets, the means of drug-receptor interactions, the mechanisms of signal transmission and amplification, and the models of inversion of effects according to the traditional 'simile' rule. These problems are handled by two experimental and theoretical lines, according to the doses or dilutions considered (low-medium versus high dilutions). Homeopathic formulations in low-medium dilutions, containing molecules in the range of ultra-low doses, exploit the extreme sensitivity of biological systems to exogenous and endogenous signals. Their effects are interpreted in the framework of hormesis theories and paradoxical pharmacology. The hypotheses regarding the action mechanisms of highly diluted/dynamized solutions (beyond Avogadro-Loschmidt limit) variously invoke sensitivity to bioelectromagnetic information, participation of water chains in signalling, and regulation of bifurcation points of systemic networks. High-dilution pharmacology is emerging as a pioneering subject in the domain of nanomedicine and is providing greater plausibility to the puzzling claims of homeopathy.

A life dedicated to research and ideal: Johannes Müller between empirical universality and idealistic vitalism mirrored in lecture notes from 1851.

Until the mid-nineteenth century, "physiology" was a comprehensive theory of life, expounded and shaped by Johannes P. Müller (1801-1858). Biologists and medical doctors still refer to him today. In the summer term of 1851, Müller gave a lecture on the Comparative Anatomy of animals. This lecture was attended and recorded by Ernst Zeller (1830-1902), a future physician and zoologist, and has recently been published together with a German transcript. In this paper, we situate Johannes Müller within the intellectual history of his time. Through his "empirical idealism," we show how he opposed the speculative tendencies of the romantic understanding of nature, the emerging evolutionism, and the growing splits in the natural sciences. Müller focused on recognizing living nature as a whole and realizing ideal "phenomena" through his empirical research. He considered the notion of the soul of the world. Müller's lecture transcript serves as a poignant testament to German scientific culture in the mid-nineteenth century, a few years before the publication of Darwin's Origin of Species. It also provides valuable insights into the self-contained epistemological foundations of morphology.

The third-way third wave and the enduring appeal of bioexceptionalism.

We may induce from a longue durée examination of Anglo-American History of Biology that the impulse to reject reduc - tionism persists and will continue to percolate cyclically. This impulse I deem "bioexceptionalism": an intuition, stance, attitude, or activating metaphor that the study of living beings requires explanations in addition to exclusively bottom-up causal explanations and the research programs constructed upon that bottom-up philosophical foundation by non-organismal biologists, biochemists, and biophysicists - the explanations, in other words, that Wadding - ton (1977) humorously termed the "Conventional Wisdom of the Dominant Group, or cowdung." Bioexceptionalism might indicate an ontological assertion, like vitalism. Yet most often in the last century, it has been defined by a variety of methodological or even sociological positions. On three occasions in the interval from the late nineteenth century to the present, a small but significant group of practicing biologists and allies in other research disciplines in the UK and US adopted a species of bioexceptionalism, rejecting the dominant explanatory philosophy of reductionistic mechanism. Yet they also rejected the vitalist alternative. We can refer to their subset of bioexceptionalism as a "Third-Way" approach, though participants at the time called it by a variety of names, including "organicism." Today's appeals to a Third-Way are but the latest eruption of this older dissensus and retain at least heuristic value apart from any explanatory success.

Vitalism and cognition in a conscious universe.

According to the current scientific paradigm, what we call 'life', 'mind', and 'consciousness' are considered epiphenomenal occurrences, or emergent properties or functions of matter and energy. Science does not associate these with an inherent and distinct existence beyond a materialistic/energetic conception. 'Life' is a word pointing at cellular and multicellular processes forming organisms capable of specific functions and skills. 'Mind' is a cognitive ability emerging from a matrix of complex interactions of neuronal processes, while 'consciousness' is an even more elusive concept, deemed a subjective epiphenomenon of brain activity. Historically, however, this has not always been the case, even in the scientific and academic context. Several prominent figures took vitalism seriously, while some schools of Western philosophical idealism and Eastern traditions promoted conceptions in which reality is reducible to mind or consciousness rather than matter. We will argue that current biological sciences did not falsify these alternative paradigms and that some forms of vitalism could be linked to some forms of idealism if we posit life and cognition as two distinct aspects of consciousness preeminent over matter. However, we will not argue in favor of vitalistic and idealistic conceptions. Rather, contrary to a physicalist doctrine, these were and remain coherent worldviews and cannot be ruled out by modern science.

An investigation of the pharmacological applications used for the Ancient Egyptian systemic model 'ra-ib' compared with modern Traditional Chinese Medicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Ancient Egyptian texts only offer glimpses into their conceptual understandings of the inner-body and illness manifestation. Explanations of how prescribed materia medica were believed to work are rare and obscure, often resulting in modern approximations for ancient terminology such as 'ra-ib'-an ancient Egyptian classification predominantly translated as 'stomach'-leading to misunderstandings of historical texts, and therefore their use of pharmacology. AIM OF THE STUDY: To investigate the ra-ib and the explanatory models of illness from the Egyptian perspective, and to explore the link between these and the prescribed selection of materia medica. To then compare the conceptual mechanics of these treatment strategies with those of another non-Western tradition-namely Traditional Chinese Medicine (TCM)-to provide further insight into potential conceptual frameworks. MATERIALS AND METHODS: We conducted a case study of a unit of Ancient Egyptian texts focusing on the ra-ib. Totalling 34 prescriptions, the first stage lexicographically analysed the texts using cognitive linguistic and translation theories to produce our new understanding. This enabled our comparison of the mechanics of materia medica usage within these texts with those found in TCM outlined by the Pharmacopoeia of the Peoples Republic of Pharmacopeia of the People's Republic of China 2015 for the relevant ingredients. RESULTS: the study demonstrated that-rather than denoting the organ 'stomach'-ra-ib instead constitutes a system running from the mouth, downward to the anus. This is best translated as 'inner thoroughfare', and changes the way in which we attempt to understand potential motivations in the selection of ingredients. By exploring common themes in the use of eleven securely translated ingredients from the Egyptian corpus and the Pharmacopoeia of the People's Republic of China-representing a modern traditional system which understands the body via a series of interconnected systems-we were able to highlight certain themes which might be 'universal' to system-based traditions; this provided new insights into the Egyptian motivations for treatment selection. CONCLUSIONS: Having gained the ancient view of the body and illness, cultural comparisons are important for providing further potential insights and clarifications of a discontinued historical healing tradition. The new understanding of the ra-ib from our study greatly changes the way in which we understand the dynamics of Egyptian ethnopharmacological source material from this period.

"Life-bearing molecules" versus "life-embodying systems": Two contrasting views on the what-is-life (WIL) problem persisting from the early days of molecular biology to the post-genomic cell- and organism-level biology.

"What is life?" is an ultimate biological quest for the principle that makes organisms alive. This 'WIL problem' is not, however, a simple one that we have a straightforward strategy to attack. From the beginning, molecular biology tried to identify molecules that bear the essence of life: the double helical DNA represented replication, and enzymes were micro-actuators of biological activities. A dominating idea behind these mainstream biological studies relies on the identification of life-bearing molecules, which themselves are models of life. Another, prevalent idea emphasizes that life resides in the whole system of an organism, but not in some particular molecules. The behavior of a complex system may be considered to embody the essence of life. The thermodynamic view of life system in the early 20th century was remodeled as physics of complex systems and systems biology. The two views contrast with each other, but they are no longer heritage of the historical dualism in biology, such as mechanism/materialism versus vitalism, or reductionism versus holism. These two views are both materialistic and mechanistic, and act as driving forces of modern biology. In reality, molecules function in a context of systems, whereas systems presuppose functional molecules. A key notion to reconcile this conflict is that subjects of biological studies are given before we start to study them. Cell- or organism-level biology is destined to the dialectic of molecules and systems, but this antagonism can be resolved by dynamic thinking involving biological evolution.

[New materia medica project: synthetic biology based bioactive metabolites research in medicinal plant].

In the last decade, synthetic biology research has been gradually transited from monocellular parts or devices toward more complex multicellular systems. The emerging plant synthetic biology is regarded as the "next chapter" of synthetic biology. The complex and diverse plant metabolism as the entry point, plant synthetic biology research not only helps us understand how real life is working, but also facilitates us to learn how to design and construct more complex artificial life. Bioactive compounds innovation and large-scale production are expected to be breakthrough with the redesigned plant metabolism as well. In this review, we discuss the research progress in plant synthetic biology and propose the new materia medica project to lift the level of traditional Chinese herbal medicine research.

Neither logical empiricism nor vitalism, but organicism: what the philosophy of biology was.

Philosophy of biology is often said to have emerged in the last third of the twentieth century. Prior to this time, it has been alleged that the only authors who engaged philosophically with the life sciences were either logical empiricists who sought to impose the explanatory ideals of the physical sciences onto biology, or vitalists who invoked mystical agencies in an attempt to ward off the threat of physicochemical reduction. These schools paid little attention to actual biological science, and as a result philosophy of biology languished in a state of futility for much of the twentieth century. The situation, we are told, only began to change in the late 1960s and early 1970s, when a new generation of researchers began to focus on problems internal to biology, leading to the consolidation of the discipline. In this paper we challenge this widely accepted narrative of the history of philosophy of biology. We do so by arguing that the most important tradition within early twentieth-century philosophy of biology was neither logical empiricism nor vitalism, but the organicist movement that flourished between the First and Second World Wars. We show that the organicist corpus is thematically and methodologically continuous with the contemporary literature in order to discredit the view that early work in the philosophy of biology was unproductive, and we emphasize the desirability of integrating the historical and contemporary conversations into a single, unified discourse.

Carbohydrate metabolism in women who used oral contraceptives containing levonorgestrel or desogestrel: a 6-month prospective study.

Blood glucose and pyruvate, plasma insulin, and glucagon levels as well as erythrocyte insulin receptors were measured during an oral glucose tolerance test in 38 normal women before and after 6 months' use of one of three new oral contraceptives containing low doses of 19 nortestosterone-derived progestogens, levonorgestrel, and desogestrel. A slight deterioration of glucose tolerance was observed, with the area under the glucose curve increasing by only 7%, 9%, and 12% after Ovidol (Aaciphar SA, Brussels, Belgium), Marvelon (Organon, SA, Brussels, Belgium), and Trigynon (Schering SA, Brussels, Belgium) administration, respectively. We did not find any argument in favor of the development of a state of insulin resistance in women using these compounds, because erythrocyte receptor binding was not modified and plasma insulin responses to glucose were decreased. The glucose-induced suppression of plasma glucagon levels seemed less effective for treatment with the desogestrel-containing preparations than with the levonorgestrel-containing oral contraceptives.

Vascular complications in women using the low steroid content combined oral contraceptive pills: case reports and review of the literature.

PIP: 5 cases of vascular complications--hemorrhagic stroke, myocardial infarction, retinal vein thrombosis, thrombotic stroke and deep vein thrombosis--in young women taking low dose oral contraceptives are described from the Department of Obstetrics and Gynecology, University of the Witwatersrand, Johannesburg, South Africa. The hemorrhagic stroke occurred in 1987 in a 24-year old heavy smoker taking Triphasil (Wyeth) for 12 months. She recovered fully. A 34-year old woman had an anteroseptal infarction while on Minovlar ED (Schering, 50 mcg ethinyl estradiol and 1 mg norethisterone acetate) for 2 years. She had no risk factors other than smoking 5 cigarettes daily. The woman with retinal vein thrombosis had 2 episodes, the 1st while taking Restovar 28 (Organon, 37.5 mcg ethinyl estradiol and 0.75 mg lynestrenol) for 7 years. 19 months later she began Diane (Schering AG, 50 mcg ethinyl estradiol and 2 mg cyproterone acetate) and had a bilateral retinal vein thrombosis leaving her partially blind. The woman with thrombotic stroke was 24 when she was struck in 1986, after 1 year of taking Logynon ED (Schering AG, 6/5/7 days, 30,40/40 mcg ethinyl estradiol and o.5/0.75/0.125 mg levonorgestrel). The patient with deep vein thrombosis was 19, smoked, and had used Triphasil for 2.5 years.^ieng

Heparin cofactor II levels are increased by the use of combined oral contraceptives.

Heparin cofactor II (HCII) was assayed by a microtitre amidolytic substrate technique. A linear response was obtained up to 1.5 U/ml and HCII levels were not affected by freezing and thawing the plasma. The assay was validated by comparing HCII and antithrombin III (AT III) levels in AT-III-deficient plasmas and samples from critically ill patients. Higher HCII levels were found in healthy normal women than in healthy normal men (means 1.16 and 0.97 U/ml, respectively, P less than 0.01). A significant increase in HCII levels from 0.86 to 1.10 U/ml (mean values) was seen in healthy normal women starting on combined oral contraceptive (COC) preparations (P less than 0.001). Increased HCII levels were maintained over a 6-month period, but fell towards normal 14 days after stopping COC, although they were still significantly higher than before starting COCs. The discrepancy in HCII level between normal men and women may be due to COC use. In clinical studies, different reference ranges should be used for men and women, and the need for careful questioning about the use of COCs is emphasized.

PIP: Heparin cofactor II, a less well characterized heparin-dependent antithrombin factor than antithrombin III, was determined in 11 women before, during and after a 6 month trial of oral contraceptives, in 16 women aged 18-60, in 16 men aged 22-55, in 5 patients with known antithrombin III deficiency, and in a series of 16 patients in a critical care unit. The oral contraceptives used in the trial were Femodene (Schering, Burgess, Hill, U.K.) in 6 women and Marvelon (Organon, Cambridge, U.K.) in 5. The assay was an amidolytic microtiter method standardized against normal human serum. The assay was linear up to 1.5 U/ml, and HCII was not lost by repeated freezing and thawing. HCII levels were normal in patients with AT III deficiency, but ranged from 0.10-1.11 in intensive care patients. In normal subjects the mean HCII levels were 1.07 U/ml, and were significantly higher for women, 1.16, than for men, 0.97 U/ml. During intake of oral contraceptives, HCII rose significantly from 0.86 u/ml to 1.10 at cycle 1, 1.08 at cycle 3, and 1.19 at cycle 6. 2 weeks after stopping pills, the mean HCII level fell to 1.03. In contrast, AT III declined during pill cycles.

Release characteristics, ovarian activity and menstrual bleeding pattern with a single contraceptive implant releasing 3-ketodesogestrel.

The properties of a single contraceptive subdermal implant releasing 3-ketodesogestrel were assessed in fifteen women over twelve months. Serum levels of 3-ketodesogestrel were monitored regularly following insertion and after removal. The mean serum level of 3-ketodesogestrel was 245 pg/ml after 72 h (steady state) and 176 pg/ml after twelve months. All volunteers demonstrated ovulation inhibition throughout the study. Transient oestradiol peaks occurred during the study. No luteal activity was noted. The cervical mucus was rapidly rendered hostile to sperm migration. Two women withdrew from the study during the first six months for medical reasons. Both volunteers cited bleeding irregularity as the main cause, one complaining of oligomenorrhoea, the other of prolonged bleeding/spotting episodes. A small but significant increase in weight was noted during the study period.

PIP: 15 sterilized women participated in a clinical trial of the implant Implanon (Organon), a single ethylene vinyl acetate rod containing 60 mg 3-ketodesogestrel (3-KDG), the metabolite of desogestrel. The rod is 40 mm long, 2 mm in diameter and is packaged in its inserter. In this trial the implants were treated to simulate the 2nd year of use. The study subjects underwent intensive hormone and ultrasound monitoring for 72 hours after insertion, twice weekly for 6 weeks and at 6-month intervals. 13 women completed 6 months, 7 completed 12 months, and 5 continued the trial 24 months. There were no complications related to insertion or removal. 3-KDG levels rose to a steady state of 245 pg/ml by 72 hours, then fell to a mean of 17 pg/ml at 12 months. 90 pg/ml of 3-KDG is the critical serum level for anovulation. After removal, 3-KDG declined to 54 pg/ml in 3 days. Follicle development tended toward small follicles or those larger than 10 mm. There was no luteal activity, and LH, FSH and progesterone remained in the follicular phase range. Estradiol levels were not low enough to risk osteoporosis. There was no significant change in serum sex hormone binding globulin. Systolic blood pressure decreased significantly at 12 months; mean weight gain was 3.7 kg (range from loss of 4 kg to gain of 22 kg); a variety of bleeding irregularities were recorded by individual women.

Clinical experience and pharmacological effects of an oral contraceptive containing 20 micrograms oestrogen.

The performance of a new low-dose oral contraceptive (Mercilon) containing only 20 micrograms ethinyloestradiol combined with 150 micrograms desogestrel is reviewed. Eight multicentre clinical trials have been completed and provide information on 10,672 women studied over 73,477 cycles. The high efficacy of Mercilon was indicated by the finding that only 10 pregnancies were reported; nine of these occurred in women who omitted to take Mercilon on a number of days and only one in a woman who took all the tablets according to instructions. Cycle control was good; as with all oral contraceptives, the incidence of breakthrough bleeding and spotting was highest in the first treatment cycle and by the sixth treatment cycle the values were usually < 5% and < 7%. More than 80% of women had regular cycles. Side effects were few, the most common being headache, nausea and breast tenderness with incidences in the sixth treatment cycle of less than 2%, 6% and 6%, respectively. There were no significant changes in body weight or blood pressure. Pharmacodynamic investigations showed no adverse effects. Only 1 of 5 studies found an increased response to a glucose tolerance test compared to the pretreatment test. In 8 of 10 studies, serum HDL-C concentrations increased on treatment and this was associated with increases in apoproteins A1 and A2. Serum triglyceride levels also increased but no change occurred in serum cholesterol or LDL-C levels. Haematological factors were assessed in 8 studies and only minor changes were observed. Serum binding protein (SHBG, CBG, caeruloplasmin) concentrations increased and serum androgen levels decreased. Measurements of blood FSH, LH, oestradiol and progesterone indicated adequate inhibition of ovulation. Mercilon is the only oral contraceptive containing 20 micrograms ethinyloestradiol to have high efficacy, to have no adverse pharmacodynamic effects and, importantly, to produce an acceptable bleeding pattern not significantly different from that of oral contraceptives with a higher content of ethinyloestradiol.