Search results for "CONGENERS"
showing 10 items of 12 documents
The swinholide biosynthesis gene cluster from a terrestrial cyanobacterium, Nostoc sp. strain UHCC 0450
2017
ABSTRACT Swinholides are 42-carbon ring polyketides with a 2-fold axis of symmetry. They are potent cytotoxins that disrupt the actin cytoskeleton. Swinholides were discovered from the marine sponge Theonella sp. and were long suspected to be produced by symbiotic bacteria. Misakinolide, a structural variant of swinholide, was recently demonstrated to be the product of a symbiotic heterotrophic proteobacterium. Here, we report the production of swinholide A by an axenic strain of the terrestrial cyanobacterium Nostoc sp. strain UHCC 0450. We located the 85-kb trans -AT polyketide synthase (PKS) swinholide biosynthesis gene cluster from a draft genome of Nostoc sp. UHCC 0450. The swinholide …
Long-term effects of oral and transdermal hormone replacement therapy on plasma homocysteine levels.
2003
Objective To compare the long-term effects of oral and transdermal hormone replacement therapy (HRT) on serum homocysteine levels in postmenopausal women. Design An open, prospective, controlled study. Seventy-five healthy postmenopausal women were recruited as eligible for the study. Fifty women seeking HRT were randomized to receive continuous 17beta-estradiol, either by oral (2 mg daily; n = 25) or transdermal (50 microg daily; n = 25) administration, plus 10 mg dydrogesterone daily for 14 days of each 28-day cycle. Twenty-five women unwilling to receive hormone treatment received only calcium supplementation, representing the control group. Fasting blood samples were analyzed at baselin…
The follicular hormonal profile in low-responder patients undergoing unstimulated cycles: is it hypoandrogenic?
2012
STUDY QUESTION What is the final hormonal milieu of pre-ovulatory follicles of low-responder (LR) patients undergoing unstimulated cycles? SUMMARY ANSWER Neither androgen secretion nor LH was impaired in pre-ovulatory follicles of LR women. WHAT IS KNOWN ALREADY Therapies currently used to improve ovarian response in LR women have an impact on the final hormonal follicular milieu, and these changes are believed to be partially responsible for determining the success rate in these women. Surprisingly, as far as we know, there is no report of the final hormonal profile of LR women undergoing unstimulated cycles or evidence that follicular androgen secretion in LR women is impaired. STUDY DESI…
Synthesis of a New Disulfide Affinity Adsorbent for Purification of Human Uterine Progesterone Receptor
2005
For purification of the human uterine progesterone receptor, an affinity adsorbent was synthesized in which the specific ligand (16 alpha-ethyl-3-oxo-19nor-androst-4-ene 17 beta-carboxylic acid) was bound to derivatized celulose using a disulfide-group-containing spacer. The purified receptor protein, isolated by reductive cleavage of the disulfide bond, bound the synthetic gestagen R5020 with high affinity (Kd 12.2 nmol/l). The affinity gel was highly efficient. A 24000-fold purification of progesterone receptor with a recovery of 40% could be achieved in a single step within 6 h. By means of dodecyl sulphate/polyacrylamide gel electrophoresis two main polypeptides with molecular weights o…
Binding of oral contraceptive progestogens to serum proteins and cytoplasmic receptor
1990
Abstract Some progestogens widely used in oral contraceptives are characterized at the level of high-affinity receptor binding as well as binding to sex hormone-binding globulin and corticosteroid-binding globulin. With regard to binding to sex hormone-binding globulin, gestodene, levonorgestrel, and to a lesser extent 3-ketodesogestrel (which is only formed from the prodrug desogestrel in the body), show a behavior that is manifested in the relatively high affinity to sex hormone-binding globulin, whereas desogestrel and norgestimate do not display any measurable affinity for this specific steroid-binding serum protein. Furthermore, levonorgestrel and gestodene dissociate very much more sl…
Neuroprotective Actions of Estradiol and Novel Estrogen Analogs in Ischemia: Translational Implications
2010
This review highlights our investigations into the neuroprotective efficacy of estradiol and other estrogenic agents in a clinically relevant animal model of transient global ischemia, which causes selective, delayed death of hippocampal CA1 neurons and associated cognitive deficits. We find that estradiol rescues a significant number of CA1 pyramidal neurons that would otherwise die in response to global ischemia, and this is true when hormone is provided as a long-term pretreatment at physiological doses or as an acute treatment at the time of reperfusion. In addition to enhancing neuronal survival, both forms of estradiol treatment induce measurable cognitive benefit in young animals. Mo…
Two-year prospective, randomized trial comparing an innovative twice-a-week progestin regimen with a continuous combined regimen as postmenopausal ho…
1999
Abstract Objective: To compare compliance, symptom control, bleeding patterns, endometrial response, and lipid changes in postmenopausal women treated with transdermal E 2 and a regimen of either intermittent or continuous dosing of progestin. Design: Randomized, prospective study. Setting: Menopausal Outpatient Clinic at an academic tertiary care hospital. Patient(s): One hundred women who had reached menopause naturally and had been amenorrheic for at least 1 year. Fifty women were randomly assigned to receive each regimen. Intervention(s): All patients received 50-μg E 2 patches and medroxyprogesterone acetate, either 5 mg twice per week or 2.5 mg daily. The bleeding pattern was register…
Biotin-Labelled and Photoactivatable Aldosterone and Progesterone Derivatives as Ligands for Affinity Chromatography, Fluorescence Immunoassays and P…
1996
New derivatives of progesterone and aldosterone were synthesized and functionally tested with commercially available antibodies. The covalent labelling of antibodies specific for aldosterone and progesterone was detected by SDS/PAGE analysis and subsequent autoradiography after using 3-(O-carboxymethyl)-oximino-(3-[125I]iodo-4-azidosalicylamidobu tylamine) derivatives of aldosterone and progesterone, respectively, as photoactivatable radioligands. Labelling was not observed in the presence of an excess of the unlabelled steroid. Aldosterone was labelled with biotin and used as a tracer in a time-resolved fluorescence immunoassay. The nonradioactive tracer is highly selective for its antibod…
Effects of Apirolio Addition and Alfalfa and Compost Treatments on the Natural Microbial Community of a Historically PCB-Contaminated Soil
2018
Abstract Polychlorinated biphenyls (PCBs) are ubiquitous and persistent organic pollutants generated exclusively from human sources and found in the environment as several congeners (e.g. Apirolio, produced in Italy and used for electrical transformers). To evaluate the ability of the natural microbial community of historically PCB-contaminated soil to transform or degrade PCBs after fresh contamination through the addition of Apirolio, a microcosm experiment was conducted in a greenhouse for approximately 8 months. Compost and Medicago sativa (alfalfa) were additionally used in the microcosms to stimulate microbial PCB degradation. Chemical analyses were performed to evaluate PCB concentra…
Estradiol reduces F2α-isoprostane production in cultured human endothelial cells
2002
Free radical-generated F2α-isoprostanes are a group of compounds with vasoconstrictor properties. To investigate whether estradiol exerts antioxidant actions modifying F2α-isoprostane production, cultured human umbilical vein endothelial cells were exposed to estradiol and other compounds and F2α-isoprostanes were measured in culture medium. Exposure to 1 and 10 nM estradiol for 24 h reduced F2α-isoprostane production by 36 and 49%, respectively ( P < 0.001 vs. control). Exposure to antiestrogens alone (ICI-182780 or EM-652) slightly reduced F2α-isoprostanes ( P < 0.05 vs. control), but much less than exposure to estradiol ( P < 0.05). ICI-182780 reversed the estradiol-induced redu…