Total ligation syndrome. Does it exist?
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Adult↗
Biomedical subjects
R C Strickler
Publications and source records attributed to R C Strickler.
Inactivation of human placental 17 beta,20 alpha-hydroxysteroid dehydrogenase by 16-methylene estrone, an affinity alkylator enzymatically generated from 16-methylene estradiol-17 beta.
The substrate 16-methylene estra-1,3,5(10)-triene-3,17 beta-diol (16-methylene estradiol-17 beta) and its enzyme-generated alkylating product, 3-hydroxy-16-methylene estra-1,3,5(10)-triene-17-one (16-methylene estrone), were synthesized to study the 17 beta- and 20 alpha-hydroxysteroid dehydrogenase activities which coexist in homogeneous enzyme purified from human placental cytosol. 16-Methylene estradiol, an excellent substrate (Km = 8.0 microM; Vmax = 2.8 mumol/mg/min) when enzymatically oxidized to 16-methylene estrone in the presence of NAD+ (256 microM), inactivates simultaneously the 17 beta- and 20 alpha-activities in a time-dependent and irreversible manner following pseudo-first order kinetics (t1/2 = 1.0 h, 100 microM, pH 9.2). 16-Methylene estradiol does not inactivate the enzyme in the absence of NAD+. 16-Methylene estrone (Km = 2.7 microM; Vmax = 2.9 mumol/mg/min) is an affinity alkylator (biomolecular rate constant k'3 = 63.3 liters/mol-s, pH 9.2; KI = 261 microM; k3 = 8.0 X 10(-4) S-1, pH 7.0) which also simultaneously inhibits both activities in an irreversible time-dependent manner (at 25 microM; t1/2 = 7.2 min, pH 9.2; t1/2 = 2.7 h, pH 7.0). Substrates (estradiol-17 beta, estrone, and progesterone) protect against inhibition of enzyme activity by 16-methylene estrone and 16-methylene estradiol. Affinity radioalkylation studies using 16-methylene [6,7-3H]estrone demonstrate that 1 mol of alkylator binds per mol of inactivated enzyme dimer. Thus, 16-methylene estradiol functions as a unique substrate for the enzymatic generation of a powerful affinity alkylator of 17 beta,20 alpha-hydroxysteroid dehydrogenase and should be a useful pharmacological tool.
20-Hydroxysteroid Dehydrogenases↗
Human placental 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase. Studies with 6 beta-bromoacetoxyprogesterone.
Two soluble enzyme activities, 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase, copurified from the cytosol fraction of human term placenta, were identically inactivated by 6 beta-bromoacetoxyprogesterone. This affinity alkylating steroid binds at the enzyme-active site (Km = 866 microM; Vmax = 0.073 mumol/min/mg). Enzyme inactivation by four concentrations of 6 beta-bromoacetoxyprogesterone (molar ratio of steroid to enzyme, 71/1 to 287/1) causes irreversible and time-dependent loss of both the 17 beta- and 20 alpha-activities according to first order kinetics and affirms that the alkylating steroid is an active site-directed inhibitor (KI = 2.7 X 10(-3) M; k3 = 1.6 X 10(-3) s-1). Affinity radioalkylation studies using 6 beta-[2'-14C]bromoacetoxyprogesterone indicate that 2 mol of steroid are bound to each mole of inactivated enzyme dimer (Mr = 68,000). Amino acid analyses of the acid hydrolysate of radioalkylated enzyme show that 6 beta-bromoacetoxyprogesterone carboxymethylates cysteine (56%), histidine (22%), and lysine (8%) residues in the active site. These results are identical with those reported for 2-bromo[2'-14C]acetamidoestrone methyl ether radioalkylation of purified "17 beta-estradiol dehydrogenase." The parallel inactivation of 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase by 6 beta-bromoacetoxyprogesterone further shows that both activities reside at a single enzyme-active site. The radioalkylation profile supports our proposed model of one enzyme-active site wherein the bound progestin and estrogen substrates are inverted, one relative to the other.
17-Hydroxysteroid Dehydrogenases↗
Maternal hydrocephalus and pregnancy.
Women with cerebrospinal fluid (CSF) shunts for correction of hydrocephalus are rapidly joining the reproductive age population. These patients can have uncomplicated pregnancies and spontaneous vaginal deliveries. Careful attention to signs of CSF shunt malfunction, historical and ultrasonic screening for familial hydrocephalus, and antibiotic prophylaxis for delivery are recommended. Management of the first and second stages of labor is discussed. There is no apparent advantage to any particular technique for intrapartum analgesia.
Adult↗
Inactivation of human placental 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase with active site-directed 17 beta-propynyl-substituted progestin analogs.
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17-Hydroxysteroid Dehydrogenases↗
20 alpha-Hydroxysteroid dehydrogenase and 17 beta-estradiol dehydrogenase localize in cytosol of human term placenta.
The 20 alpha-hydroxysteroid dehydrogenase activity in human term placenta has been localized by different investigators to nuclear, mitochondrial, microsomal, and cytosolic subcellular fractions. Furthermore, in the cytosol, 20 alpha-hydroxysteroid dehydrogenase activity may be a second function of the enzyme that mediates 17 beta-estradiol dehydrogenase activity. To search for a unique 20 alpha-hydroxysteroid dehydrogenase, human placental villous tissue, homogenized in three different buffer systems, was fractionated by differential centrifugation, and the 17 beta- and 20 alpha-activities were measured by radioisotope conversion assay. The enrichment and purity of the subcellular fractions were shown by marker enzyme assays and electron microscopy studies. Under all experimental conditions, 20 alpha-hydroxysteroid dehydrogenase activity was identified only in the 105,000 g placental cytosol: intact, osmotically ruptured, and acetone-extracted mitochondria, nuclei, and microsomes did not convert progesterone to 20 alpha-dihydroprogesterone. Furthermore, because 17 beta-estradiol dehydrogenase activity was in large part soluble in the cytosol, these localization studies are consistent with the hypothesis that the 20 alpha- and 17 beta-oxidoreductase activities in human placenta reside on one soluble protein.
17-Hydroxysteroid Dehydrogenases↗
Affinity labeling of human placental 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase with 5'-[p-(fluorosulfonyl)benzoyl]adenosine.
Two pyridine nucleotide linked oxidoreductase activities, 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase, which were copurified from human placental cytosol as a homogeneous enzyme preparation, may represent dual activity by one enzyme. The affinity labeling nucleotide analogue 5'-[p-(fluorosulfonyl)benzoyl]adenosine, which binds at the cofactor site as a competitive inhibitor of NADH (ki = 1.7 mM), simultaneously and identically inactivated both the 17 beta and 20 alpha activities in a time-dependent and irreversible manner following pseudo-first-order kinetics. NADH and NAD+ markedly protected both activities from inactivation, and the substrate steroids, estrone, estradiol, progesterone, and 20 alpha-hydroxy-4-pregnen-3-one, conferred similar protection, though less than cofactor, against simultaneous loss of both activities. Stoichiometric studies indicated that 2 mol of affinity labeling nucleotide were bound per mol of completely inactivated enzyme dimer. The coincident and identical loss of both activities under all experimental conditions is further evidence that 17 beta-estradiol dehydrogenase and 20 alpha-hydrosteroid dehydrogenase in human placental cytosol represent bifunctional, stereospecific, oxidoreductase activity at one active site on a single protein.
17-Hydroxysteroid Dehydrogenases↗
Daily and circadian variations in serum free testosterone levels are not clinically significant.
Serum free testosterone levels were measured daily during an ovulatory, endocrinologically normal cycle in five women and at 6-hour intervals on six consecutive days near midcycle in four of these women. During ovulatory cycles, serum free and total testosterone, unlike the gonadotropins, estradiol, and progesterone, did not fluctuate in a cyclic pattern. The 6-hour assays demonstrated close parallelism of free and total testosterone levels and no circadian pattern similar to the diurnal variation seen in serum cortisol values. During both study intervals, the serum free testosterone levels rarely exceeded the upper limit of the normal range defined for our laboratory. Thus, serum free testosterone values measured in blood samples obtained at any day are equally reliable for clinical use.
Circadian Rhythm↗
Human placental 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase. Two activities at a single enzyme active site.
Two soluble enzyme activities, 17 beta-estradiol dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase, present in the cytosol fraction of term human placenta, were co-purified with a constant ratio of specific activities, approximating 100:1, respectively. The "pure enzyme" is a single band on sodium dodecyl sulfate disc gel electrophoresis. To evaluate whether catalysis of the estrogen and progestin substrates occurs at a single active site, alkylation studies using 16 alpha-bromoacetoxyprogesterone were designed. This affinity alkylating steroid binds at the enzyme-active site (km 256 microM; Vmax = 0.012 mumol/min/mg), inactivates the enzyme in an irreversible and time-dependent manner which follows pseudo-first order kinetics, and causes coincident loss of both the 17 beta- and 20 alpha-activities. Affinity radioalkylation studies using 16 alpha-[2'-3H]bromoacetoxyprogesterone indicate that 2 mol of steroid bind per mol of inactivated enzyme dimer (Mr = 68,000). Amino acid analyses of the acid hydrolysate of radioalkylated enzyme show that 16 alpha-bromoacetoxyprogesterone dicarboxymethylates a histidyl residue in the active site. These results are identical with those reported for 16 alpha-[2'-3H]bromoacetoxyestradiol 3-methyl ether inactivation and radioalkylation of identically purified "17 beta-estradiol dehydrogenase." Computer graphics were used to construct a model in which: 1) binding of estrogen and progestin substrates at one active site permits stereospecific catalysis; 2) the estrogen and progestin analogs' alkylating side arms have access to a common histidine residue. These observations clearly demonstrate that the catalysis of estrogen and progestin substrates can occur at a single active site of one enzyme.
17-Hydroxysteroid Dehydrogenases↗
Photoactivated zinc silicate in thin layer chromatography plates: a potential cause for error in liquid scintillation counting.
Thin layer chromatography plates impregnated with fluorescent indicator permit easy identification of many compounds by exposure to ultraviolet light. Exposure of zinc silicate treated plates to ultraviolet light (254 nm) for 30 seconds induced photoluminescence which persisted at significant levels for longer than 24 hours. This artifact significantly interfered with radioactivity quantitation in three commercially available liquid scintillation solutions. Chromatography plates impregnated with calcium silicate demonstrated insignificant ultraviolet light induced photoluminescence. The use of 14C rather than 3H-radiolabeled compounds, protecting the plate with aluminum foil when visualizing reference compounds with ultraviolet light, and heating the photoactivated plate to accelerate disappearance of the photoluminescence minimized the error in liquid scintillation counting.
20-Hydroxysteroid Dehydrogenases↗
Study of human placental estradiol-17 beta dehydrogenase/20 alpha-hydroxysteroid dehydrogenase by preparative disc-gel electrophoresis.
The soluble enzyme, estradiol-17 beta dehydrogenase from human term placenta, appears to co-purify with a second soluble enzyme, 20 alpha-hydroxysteroid dehydrogenase. The enzyme, which had been partially purified by affinity chromatography, fractionated on a preparative electrophoresis gel to a homogeneous preparation containing both estradiol-17 beta dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase activities in a ratio of approximately 100:1. Analytical polyacrylamide disc-gels resolved this homogeneous preparation as a single band by both protein and activity staining techniques. Homogeneous enzyme inactivated and affinity-radioalkylated by 16 alpha-[2'-14C]bromoacetoxyprogesterone or 16 alpha-[2'-14C] bromoacetoxyestradiol 3-methyl ether, and when analyzed by SDS disc-gel electrophoresis, gave a single protein band which corresponded identically to the radioactivity peaks. These observations support the hypothesis that estradiol-17 beta dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase represent dual oxidoreductase activity in one enzyme. Preparative disc-gel electrophoresis, a technique which has not been previously adapted to purification of these human placental enzyme activities, was useful to rapidly (3 days) effect a 15-fold enrichment of the estradiol-17 beta dehydrogenase specific activity from "heat-treated cytosol". Thus, laboratory-scale preparative disc-gel electrophoresis is useful for rapid, small-scale enrichment of this soluble enzyme.
17-Hydroxysteroid Dehydrogenases↗
Study of 3 alpha, 20 beta-hydroxysteroid dehydrogenase with an enzyme-generated affinity alkylator: dual enzyme activity at a single active site.
The substrate 17 beta-[(1S)-1-hydroxy-2-propynyl]-androst-4-en-3-one (beta-HPA) and its enzyme-generated alkylating product 17 beta-(1-oxo-2-propynyl)androst-4-en-3-one (OPA) were synthesized to investigate the relationship between the 3 alpha and 20 beta activities observed in commercially available cortisone reductase (EC 1.1.1.53) from Streptomyces hydrogenans. beta-HPA, a substrate [apparent Km = 145 microM; Vmax = 63 nmol (min microgram)-1], when enzymatically oxidized by cortisone reductase of OPA, inactivates simultaneously the 3 alpha and 20 beta activities in a time-dependent and irreversible manner following pseudo-first-order kinetics. OPA alone, an affinity alkylating steroid (KI = 40.5 microM; k3 = 1.8 X 10(-2) S-1), simultaneously inactivates 3 alpha and 20 beta activities in a time-dependent and irreversible manner. At pH 7, the t 1/2 of enzyme inactivation for beta-HPA (10 h) or OPA (41 min) is slower than at pH 9.2 (beta-HPA, 16 min, and OPA, 3.3 min). Substrates (progesterone, 20 beta-hydroxypregn-4-en-3-one, and 5 alpha-dihydrotestosterone), but not all steroids (20 al]ha-delta 4-pregn-4-en-3-one and 17 beta-estradiol), protect against loss of both enzyme activities by beta-HPA and OPA. The alpha isomer of HPA is not enzymatically oxidized and therefore does not cause inactivation of either 3 alpha or 20 alpha activity. Thus, beta-HPA functions as a substrate for the enzymatic generation of a powerful affinity alkylator of cortisone reductase. Second, the identical change in both the 3 alpha and 20 beta activities in all experimental conditions clearly results from dual enzyme activity at a single enzyme active site.
20-Hydroxysteroid Dehydrogenases↗
Estradiol 17 beta-dehydrogenase and 20 alpha-hydroxysteroid dehydrogenase from human placental cytosol: one enzyme with two activities?
The soluble enzyme estradiol 17 beta-dehydrogenase (17 beta-ED) from human term placental cytosol is reported to be a stereospecific oxidoreductase for estrogen substrates. A published purification scheme (heat treatment and affinity chromatography) yielded a homogeneous protein which had the reported characteristics of pure 17 beta-ED and also had 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) activity. Spectrophotometric assay when the buffer contained albumin, 8 mg/ml, masked the 20 alpha-HSD activity observed in albumin-free conditions and may explain why this bifunctional activity has gone unrecognized. In human placenta, one enzyme may catalyze stereospecific oxidation/reduction of both estrogen and progesterone.
17-Hydroxysteroid Dehydrogenases↗
Inadvertent primary vaginal incision during cesarean section.
A previously undescribed complication of low transverse cesarean section--primary entry into the upper vagina--is reported in two women. The patient at risk is a parturient whose cervix is completely dilated and who has been pushing the second stage labour. Possible complications include bladder injury, vesical fistula, hemorrhage and laceration of adjacent ligamentous structures. Management requires meticulous hemostasis, careful search for bladder injury and anatomical closure of the vaginal defect. The postoperative course and prognosis of well managed cases are good.
Adult↗
Delayed hemorrhage in conservative surgery for ectopic pregnancy.
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Adult↗
Dysfunctional uterine bleeding: diagnosis and treatment.
Dysfunctional uterine bleeding is not a specific diagnosis. It encompasses a spectrum of endocrinologic dysfunction which must be considered in reference to the presence or absence of ovulation. Specific causes must not be forgotten, particularly in those women who do not respond as expected to hormonal therapy. A variety of empiric therapies are used which have no benefit, such as thyroid hormone in the absence of proven hypothyroidism, corticosteroid in the absence of proven adrenal hypofunction, and megavitamin therapies in the absence of nutritional disorders. Curettage is valuable for diagnosis, not for therapy. Medical therapy offers a successful alternative to hysterectomy in many women, but the choice must be made on an individual basis. Medical and surgical management should not be viewed as competitive treatment regimens.
Adolescent↗
Pseudocorpus luteum insufficiency: a local defect of progesterone action on endometrial stroma.
A 23-yr-old woman whose initial complaint was infertility demonstrated glandular stromal dissociation with failure of the endometrial stroma to undergo pseudodecidualization in repeated endometrial biopsies taken late in the luteal phase. As the clinical presentation was consistent with the inadequate corpus luteum syndrome, hormone measurements were performed. The endometrial biopsy was abnormal during cycles in which the serum pattern of progesterone, estradiol, FSH, and LH was normal. Exogenous progesterone did not correct the abnormality. The patient, by in vitro studies, has approximately one half the number of high affinity progesterone-binding sites in the cytosol fraction of her endometrium compared to preparations from two normal control subjects. Since her cytosol-binding protein was qualitatively identical to two control subjects, the incomplete maturation of her endometrial stroma may represent an absence or reduced number of stromal cytosol receptors and/or a resistance to specific hormone action in an individual target tissue.
Adult↗
Elective removal of an intrauterine device.
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Adult↗