Publications by authors named "Santen R"

The Endocrine Society formally addressed the issue of retirement for its members for the first time in a Workshop held on June 4 at ENDO 2024 in Boston, Massachusetts. Preparation for the workshop included 4 steps: (1) completion of a survey; (2) advice from a retirement expert; (3) extensive literature review; and (4) multiple pre-workshop discussions among the presenters. The survey found that retired endocrinologists are involved in a wide variety of professional and nonprofessional activities.

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Context: Approximately 150 patients with juvenile gigantomastia have been reported in the literature but the underlying biologic mechanisms remain unknown.

Objective: To conduct extensive clinical, biochemical, immunochemical, and genetic studies in 3 patients with juvenile gigantomastia to determine causative biologic factors.

Methods: We examined clinical effects of estrogen by blockading estrogen synthesis or its action.

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Objective: To identify early available predictors for the long-term outcome of patients after transsphenoidal surgery (TSS) in the management of Cushing's disease.

Methods: This single-center, retrospective study included 93 consecutive patients with Cushing's disease (follow-up 12-129 months, mean 48, median 38) who underwent TSS (21 had previous operations elsewhere). Six cases had early re-operation, and the resulting data were evaluated instead of the respective first operation.

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Introduction: Endocrinology workforce data demonstrate a substantial gap in the number of practicing endocrinologists, a phenomenon particularly affecting patients with diabetes in rural, financially challenged, underserved areas. We evaluated the concept that retired endocrinologists could re-enter practice part time and utilize telemedicine in collaboration with personnel in Federally Qualified Community Health Center clinics to conduct an intensive self-management program and provide 6-month concurrent care for patients with diabetes.

Methods: The program involved intensive glucose control measures and education in diabetes, nutrition, and lifestyle changes over a 6-month period.

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Purpose: Current concepts regarding estrogen and its mechanistic effects on breast cancer in women are evolving. This article reviews studies that address estrogen-mediated breast cancer development, the prevalence of occult tumors at autopsy, and the natural history of breast cancer as predicted by a newly developed tumor kinetic model.

Methods: This article reviews previously published studies from the authors and articles pertinent to the data presented.

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Some fundamental concepts of catalysis are not fully explained but are of paramount importance for the development of improved catalysts. An example is the concept of structure insensitive reactions, where surface-normalized activity does not change with catalyst metal particle size. Here we explore this concept and its relation to surface reconstruction on a set of silica-supported Ni metal nanoparticles (mean particle sizes 1-6 nm) by spectroscopically discerning a structure sensitive (CO hydrogenation) from a structure insensitive (ethene hydrogenation) reaction.

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Menstrual cyclicity is a marker of health for reproductively mature women. Absent menses, or amenorrhea, is often the initial sign of pregnancy-an indication that the system is functioning appropriately and capable of generating the intended evolutionary outcome. Perturbations of menstrual regularity in the absence of pregnancy provide a marker for physiological or pathological disruption of this well-orchestrated process.

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The case of a symptomatic, postmenopausal woman is presented and a full discussion of the approach to her management is discussed. Pertinent guidelines and scientific evidence are emphasized as support for the recommendations.

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The North American Menopause Society (NAMS) organized the Workshop on Normal Ranges for Estradiol in Postmenopausal Women from September 23 to 24, 2019, in Chicago, Illinois. The aim of the workshop was to review existing analytical methodologies for measuring estradiol in postmenopausal women and to assess existing data and study cohorts of postmenopausal women for their suitability to establish normal postmenopausal ranges. The anticipated outcome of the workshop was to develop recommendations for establishing normal ranges generated with a standardized and certified assay that could be adopted by clinical and research communities.

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The recent Collaborative Group on Hormonal Factors in Breast Cancer (CGHFBC) publication calculated the attributable risk of breast cancer from use of estrogen alone and estrogen plus a synthetic progestogen for less than 5 to 15 or more years of use. This CGHFB report calculated attributable risk based on their findings of relative risk from pooled data from 58 studies. Notably, neither the CGHFBC nor other previous studies have examined the effect of underlying risk of breast cancer on attributable risk.

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Objectives: To critically evaluate published systemic estradiol levels during use of low-dose vaginal estrogens considering detection method and estrogen dose; describe challenges with accurately measuring estradiol; and determine the normal estradiol level range in postmenopausal women.

Methods: PubMed was searched for studies reporting systemic estradiol levels with lower-dose vaginal estrogens (≤25 μg estradiol or 0.3 mg conjugated equine estrogens).

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Purpose: Postmenopausal women with estrogen receptor-positive breast cancers often respond initially to tamoxifen or aromatase inhibitor therapy. Resistance to these treatments usually develops within 12 to 18 months. Clinical studies have demonstrated that high-dose estrogen can induce regression of these endocrine-resistant tumors.

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Women with estrogen-sensitive cancer or survivors of these neoplasms are generally not candidates for systemic menopausal hormone therapy or tibolone for the treatment of bothersome vasomotor symptoms (hot flashes or night sweats). However, menopausal symptoms negatively affect quality of life and need to be addressed by clinicians. For mild vasomotor symptoms, optimizing lifestyle changes or mind-brain behavior may be sufficient.

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Context: Challenging clinical scenario in which elevated β-human chorionic gonadotropin (HCG, subsequently termed HCG) levels suggested occult tumor metastases after removal of bilateral testicular cancers and metastases from them and as well as after chemotherapy.

Case Report: A 22-year-old male, post excision of bilateral testicular tumors, who had no imaging or clinical evidence of residual tumor but an elevated HCG raising the question of the presence and location of occult tumor metastases. Clinical Questions.

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This mini-review summarizes key points from the Clark Sawin Memorial Lecture on the History of Estrogen delivered at Endo 2018 and focuses on the rationales and motivation leading to various discoveries and their clinical applications. During the classical period of antiquity, incisive clinical observations uncovered important findings; however, extensive anatomical dissections to solidify proof were generally lacking. Initiation of the experimental approach followed later, influenced by Claude Bernard's treatise "An Introduction to the Study of Experimental Medicine.

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The existing medical literature suggests that estrogens may cause breast cancer but, paradoxically, can also prevent this neoplasm under specific circumstances. Appropriate interpretation of this complex data requires an understanding of emerging concepts of tumor biology. A substantial body of data, including animal models and epidemiologic studies, suggests that estrogens contribute to the development of breast cancer.

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Propylene oxide (PO) is one of the 50 most produced chemicals according to the production volume. Environmental and economic drawbacks of conventional PO production processes necessitate new production methods. Among the new production alternatives, direct epoxidation of propylene to propylene oxide by molecular oxygen is a highly desired method and seen as the holy grail of propylene epoxidation studies.

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Differences in catalyst deactivation kinetics in solid acid catalysis are studied with catalyst models that allow for lateral interaction between protons. Deactivation of a solid acid catalyst with laterally interacting protons induces inhomogeneity of proton reactivity that develops with time. As a consequence, product selectivity changes and deactivation will accelerate.

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Objective: The established link between oestrogen and breast cancer occurs via both oestrogen receptor (ER)-mediated and non ER-mediated mechanisms. The term genotoxic estrogens describes mutagenic metabolites, including oestrogen catechols and quinones, which have been linked to breast carcinogenesis in post-menopausal women. We aimed to assess whether the route of administration of 17β oestradiol (E ) affects the accumulation of genotoxic oestrogen metabolites in a model of ovarian failure in young girls with Turner syndrome.

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Background: The glucocorticoid receptor (GR) consists of two alternatively spliced isoforms: GRα, which activates gene transcription, and GRβ, a dominant-negative receptor. Theoretically, inactivating variants of GRβ could result in glucocorticoid hypersensitivity.

Design: A 46-year-old woman presented for evaluation of adrenal insufficiency prompted by low plasma cortisol levels and multiple unexplained symptoms but without clinical evidence of glucocorticoid insufficiency.

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New insights and successful use of computational catalysis are highlighted. This is within the context of remaining issues that prevent theoretical catalysis to be fully predictive of catalyst performance. A major challenge is to include in modelling studies the transient initiation as well as deactivation processes of the catalyst.

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The Women's Health Initiative studies reported that the menopausal hormone therapy (MHT) regimen containing conjugated equine estrogen (CEE) and medroxyprogesterone acetate increased, whereas CEE alone reduced breast cancer incidence. These observations suggest the possibility that CEE might exert unique actions on breast and also suggest the need to eliminate the progestogen from MHT regimens. A MHT regimen called a tissue selective estrogen complex (TSEC), containing CEE plus bazedoxifene (BZA), to avoid the need for a progestogen, was developed and FDA approved.

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