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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

4-Hydroxyestradiol bearing a 3H label specifically at C-2 was prepared chemically and incubated with male rat liver microsomes or mushroom tyrosinase. A very high proportion (80-90%) of the 3H was displaced from the labeled steroid when either glutathione or N-acetylcysteine was present, and tyrosinase was shown not to require NADPH as cofactor for this reaction. In either case, only negligible amounts (less than 3%) of the 3H radioactivity were found associated with water-soluble adducts in contrast to 3H-labeled 2-hydroxyestradiol, which gave rise to about 25% of such products. The effect of ascorbic acid on the microsomal reaction with regiospecifically labeled estradiol, 2-hydroxyestradiol, and 4-hydroxyestradiol was also investigated, and the results are discussed in terms of the reactivity at different carbon atoms in ring A of the catechol estrogens. All the evidence points to conjugation of 4-hydroxyestradiol with glutathione or N-acetylcysteine at C-2 but not C-1 of this highly reactive catechol estrogen. Measuring the displacement of 3H as 3H2O from specific positions in the steroid ring provides a useful and sensitive method to assess the formation of adducts in cases where their isolation and characterization is particularly difficult.
Steroids
PMID:4-Hydroxyestradiol is conjugated with thiols primarily at C-2: evidence from regiospecific displacement of tritium by rat liver microsomes or tyrosinase. 285 Dec 1

The 1H- and 13C-nmr spectra of mestranol were assigned with the help of a 2 D-J-resolved, a 2D spin echo J-correlated (SECSY) and a 2D 1H-13C hetero-shift correlation experiment. The analysis of the spectra facilitated the identification of some of the photodecomposition products of mestranol. It was shown that, upon irradiation with UV-B light in water-ethanol (1:1, v/v), products are formed by oxidation of rings B and C of the steroid.
Steroids 1985 Feb
PMID:Mestranol: the assignment of its 1H and 13C NMR spectra by means of two-dimensional NMR spectroscopy, and its photochemical decomposition. 300 71

Alkaline ingestion is a potentially life-threatening problem that may confront the emergency physician. It is similar to many other toxins in that children and those who attempt suicide are its most common victims; however, implications in terms of initial stabilization and definitive care are quite distinct. Mucosal exposure to lye results in a quick, deep liquefactive necrosis. Consequently, blind nasotracheal intubation may result in the perforation of damaged tissues in the pharynx and trachea. For similar reasons, the blind passage of a nasogastric tube is contraindicated. The use of diluents in this setting is controversial. If a diluent is used, water and milk are considered the liquids of choice. They may be used to irrigate oropharyngeal burns, but are contraindicated in the face of respiratory compromise, shock, liquid lye ingestion, and perforation of the esophagus or stomach. Cathartics and charcoal are not used after alkaline ingestion. Cathartics, however, are used in miniature alkaline battery ingestions to diminish bowel transit time. Esophagoscopy should be done within 12 to 24 hours after ingestion to directly observe the extent of damage. This procedure should be stopped at the first sign of injury to protect against iatrogenic esophageal perforation. Steroids should be started for circumferential esophageal burns and in those patients with significant injury who are unable to undergo esophagoscopy. IV antibiotics are administered for gastrointestinal perforation and may be used concomitantly with steroids. Miniature alkaline batteries lodged in the esophagus must be removed immediately. The available modalities include fluoroscopy-directed Foley catheter removal, endoscopy, and surgery.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alkaline ingestions. 352 23

We developed sensitive, specific "high-performance" liquid chromatography (HPLC) for determining suppressed cortisol and corticosterone in human plasma and compared its efficacy with that of conventional radioimmunoassay (RIA) at concentrations in the nanogram per liter range. Steroids from a 0.5-mL aliquot of plasma were extracted by rapid-flow fractionation, with diethyl ether as mobile-phase solvent, diatomaceous earth granules as stationary-support material. Analytical recovery of the steroids approached 100%. Concentrations in plasma were determined from peak-height ratio calibration (dexamethasone internal standard). The analytical column contained silica gel and the solvent system was water/methanol/dichloromethane/n-hexane (0.1/3/30/66.9 by vol). We could measure the steroids before and 20 h after oral administration of 0.5 mg of dexamethasone. The detection limit was 300 ng per liter of plasma for corticosterone, 500 ng/L for cortisol, with CVs of less than 4%. Determining corticosterone after administration of dexamethasone, in four of 20 such samples we could determine concentrations greater than 300 ng/L; the others contained corticosterone between 100 and 300 ng/L, but these values could not be certified analytically. Mean concentrations of these hormones as determined by RIA substantially exceeded those by HPLC. Some cross reactions in RIA could not be considered negligible in spite of pre-column treatment of the extracts.
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PMID:Liquid chromatography and radioimmunoassay compared for determination of cortisol and corticosterone in plasma after a dexamethasone suppression test. 362 64

The analysis of various steroid classes by thermospray HPLC-MS using solvent systems containing 0.1 M ammonium acetate has been described. For simple unconjugated 3-oxo-4-ene steroids the positive ion spectra are dominated by a parent ion M + H+ and with increasing numbers of hydroxyl group intense ions formed by sequential losses of water (M + H- n18)+ become important. Steroids with dihydroxyacetone side-chains readily lose these side-chains and the resulting (M + H-60)+ fragment is the base peak in their spectra. The (M + H-60)+ ion is not important for most steroids with glycerol-type side-chains. Although competition between thermal degradation and vaporization was observed at lower concentrations, the effect was minimized after optimizing conditions and the protonated molecular ion was easily detected when as little as 1-10 pmol of material were injected on-column. Steroid glucuronides when analyzed in the negative ion mode give simple spectra with base peak and parent ion (M-H)-. Lack of fragmentation permits facile and sensitive measurement of individual glucoronides by selected-ion-monitoring. Extensive fragmentation is seen in the positive ion mode with sequential losses of H2O from the molecular ions (M + NH4)+ and from the aglycone fragment ion. For simple unconjugated steroids the sensitivity of HPLC-MS in selected-ion-monitoring mode can be excellent. When the protonated molecular ion of testosterone was monitored the signal/noise ratio for 30 pg testosterone was about 10.
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PMID:Thermospray HPLC/MS: a new mass spectrometric technique for the profiling of steroids. 369 97

Mature female rats given food and water ad libitum and maintained under a lighting schedule of 12h light/12h dark were treated with boldenone undecylenate. Neither dosage nor duration of treatment had a significant effect on weight gain when compared to controls. All treated females were characterized by the absence of cyclic ovarian activity that continued for several weeks following termination of treatment. Long term reproductive performance was altered by a significant reduction in both conception rate and neonatal survival. Behavioral patterns were modified for several months following steroid withdrawal.
Steroids 1985 Jun
PMID:Effects of an anabolic steroid on reproduction in female rats. 383 28

Ketoconazole (K) is an antifungal imidazole derivative which has been shown to be a potent inhibitor of testosterone (T) biosynthesis in rodents and humans. To study the effect of K on rat testicular steroidogenesis we measured the activities of five testicular microsomal steroidogenic enzymes in K-treated rats and controls. Thirty male adult rats were given either 2 mg K or water every 12 hours by mouth during 5 days. Mean testicular weight was similar in both groups of animals. The K-treated group had a T serum concentration of 83 +/- 14 ng/dL whereas it was 94 +/- 16 ng/dL in the control group (NS). The K-treated animals had decreased activities of the 3 beta-hydroxysteroid dehydrogenase (830 +/- 48 vs 2,245 +/- 109 pmol/mg protein/min, P less than 0.001), 17-hydroxylase (243 +/- 5 vs 676 +/- 17 pmol/mg protein/min, P less than 0.001), 17-ketosteroid reductase (31 +/- 2 vs 169 +/- 7 pmol/mg protein/min, P less than 0.001), and aromatase enzymes (92 +/- 6 vs 123 +/- 7 pmol/mg protein/min, P less than 0.01). The 17,20-desmolase activity was similar in both groups of animals (210 +/- 4 vs 171 +/- 18 pmol/mg protein/min). We conclude that K given orally to rats inhibits the activity of several testicular steroidogenic enzymes.
Steroids 1985 Jul
PMID:Effects of ketoconazole on rat testicular steroidogenic enzymatic activities. 387 79

We performed a randomized double-blind trial to determine the usefulness of early methylprednisolone therapy for patients with pulmonary failure. We selected 81 acutely ill, mechanically ventilated patients at high risk for adult respiratory distress syndrome (ARDS). Thirty-nine patients received methylprednisolone, 30 mg/kg, every six hours for 48 hours; 42 patients received mannitol placebo. All patients were given a positive end-expiratory pressure of 5 cm H2O, monitored with pulmonary artery catheters, and treated for their primary disease processes. Twenty-five steroid-treated patients (64%) and 14 placebo-treated patients (33%) developed ARDS. Early infectious complications occurred in 30 steroid-treated patients (77%) and 18 placebo-treated patients (43%). There were no significant differences in factors predisposing to ARDS, ventilatory requirements, or days of intensive care. These results do not support the use of methylprednisolone for ARDS. Steroids failed to improve pulmonary function and were associated with an increased infection rate. Intensive pulmonary and general supportive care remain the preferred therapy for ARDS.
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PMID:Early steroid therapy for respiratory failure. 388 15

Concanavalin A-Sepharose (Con A-Sepharose) was applied to separate non-protein-bound and albumin-bound radioactive impurities from steroid radioligands. Con A-Sepharose gel, plasma, and steroid radioligand were mixed, incubated, and then washed with buffer. This method was compared with an affinity diafiltration method which separates non-protein-bound radioactive impurities with a filter membrane. 3H-Water and 3H-estrone sulfate, chosen to serve as molecules representative of non-protein-bound and albumin-bound impurities, were removed quite effectively by the Con A-Sepharose method, while 85% of 3H-estrone sulfate could not be removed by the diafiltration method. Plasma unbound cortisol (F) and testosterone (T) values determined by ultrafiltration using 3H-F and 3H-T prepared by the Con A-Sepharose method were significantly lower than those determined using the radioligands unprocessed or prepared by the diafiltration method. The whole procedure of the Con A-Sepharose method takes only 3-4 hours. This method is a simple, rapid, and effective technique for preparation of steroid radioligands for plasma protein binding studies.
Steroids 1985 Jan
PMID:Preparation of steroid radioligands for ultrafiltration assays by a solid-phase transport globulin method using concanavalin A-Sepharose. 408 12

The estrogenic properties of estrazinol hydrobromide (EZ), a water-soluble estrogen, were compared with those of Premarin (PR), another water-soluble estrogen preparation consisting of conjugated equine estrogens. Estradiol-17beta, estra-1,3,5(10)-triene-3,17beta-diol (E), and ethinyl estradiol, 17alpha-ethinyl-1,3,5 (10)-estratriene-3,17beta-diol (EE) were used as reference standards. Subcutaneous progesterone (400 mcg) given to rabbits primed with comparable subcutaneous doses of either E or EE produced full secretory changes of the endometrium, while such a transformation could not be elicited in orally primed animals regardless of the estrogen used. The biological profile or orally administered EZ was very similar to that of oral EE and different from oral PR. Howerver, the oral EZ-induced morphological changes of the rabbit endometrium appeared somewhat different from those produced by oral EE. The findings indicated that following oral administration, EZ-induced endometrial transformation is more "normal" and/or adequate than the changes produced by either EE or PR.
Steroids Lipids Res 1973
PMID:Estrogenic profile on a water-soluble estrogen, estrazinol hydrobromide. 436


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