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At least 919 records · Page 51Linked to original sources
PubMed1999

Differential effects of natural and synthetic glucocorticoids on cytochrome 17alpha-hydroxylase (P-45017alpha) and cytochrome P-450 side-chain cleavage (P-450scc) messenger ribonucleic acid in the sheep placenta.

OBJECTIVE: Our purpose was to determine differential effects of natural and synthetic glucocorticoids on cytochrome 17alpha-hydroxylase and cytochrome P-450 side-chain cleavage messenger ribonucleic acid in the sheep placenta and to determine whether feed-forward effects during labor are involved in further inducing placental cytochrome 17alpha-hydroxylase. STUDY DESIGN: Sheep underwent placement of myometrial electromyogram electrodes while they were under general anesthesia at 117 days' gestation. At 125 days' gestation either saline solution (early control animals not in labor, n = 5), 0.48 mg betamethasone during 48 hours (n = 7), 0.48 mg dexamethasone during 48 hours (n = 7), or 55 mg cortisol during a maximum of 96 hours (n = 4) was directly administered intravenously to the fetus. Necropsies were performed at 127 to 129 days' gestation. We also studied 6 ewes in spontaneous term labor at 143-147 days' gestation, 6 term control animals not in labor at 140 to 147 days' gestation, and 6 sheep in which myometrial activity was inhibited by intravenous infusion to the ewe of the selective cyclooxygenase 2 inhibitor nimesulide 9 hours after the onset of labor beginning at 147 to 148 days' gestation. Total fetal placental ribonucleic acid was analyzed by Northern blot with complementary deoxyribonucleic acid probes for cytochrome 17alpha-hydroxylase, cytochrome P-450 side-chain cleavage, and 18S ribosomal ribonucleic acid to correct for loading. RESULTS: Placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was detectable neither in term control animals not in labor nor in early control animals not in labor. Placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was induced in spontaneous term labor and all cortisol-infused sheep in labor with respect to term control animals not in labor and early control animals not in labor (P <.01). All betamethasone-infused sheep had myometrial contraction activity; however, only 4 of 7 had detectable placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid. Placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was not detected in dexamethasone-infused sheep, even the 2 that had myometrial contractions. After reversal of the progression of spontaneous labor with nimesulide placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was significantly lower than the spontaneous term labor group (without nimesulide treatment). The placentas from all animals expressed cytochrome P-450 side-chain cleavage messenger ribonucleic acid, but no changes were associated with either gestational age studied (130 versus > 140 days' gestation) or glucocorticoid-induced premature labor and spontaneous term labor. CONCLUSIONS: (1) In sheep the expression of placental cytochrome 17alpha-hydroxylase is tightly associated with spontaneous term labor, and active synthesis of placental cytochrome 17alpha-hydroxylase is required during the progression of labor. (2) Cortisol is a more potent stimulator of placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid in sheep than are synthetic glucocorticoids. (3) Betamethasone has a greater effect in inducing labor in sheep than does dexamethasone, possibly mediated through placental cytochrome 17alpha-hydroxylase.

Animals↗
PubMed2003

Clinical impact of carcinoembryonic antigen messenger ribonucleic acid expression in tumor-draining vein blood on postoperative liver metastasis in patients with colorectal carcinoma: a prospective, cohort study.

PURPOSE: This study was designed to determine the clinical impact of carcinoembryonic antigen messenger ribonucleic acid expression in tumor-draining vein blood on postoperative liver metastasis in patients with colorectal carcinoma. METHODS: The study comprised 37 patients with colorectal carcinoma who underwent laparotomy (Dukes A, 3; Dukes B, 16; Dukes C, 15; and Dukes D, 3). Blood samples were drawn from the tumor-draining vein and the tumor-feeding artery. Total ribonucleic acid was extracted from the blood and subjected to reverse transcriptase-polymerase chain reaction to detect carcinoembryonic antigen messenger ribonucleic acid. Tissue sections of tumor were stained with hematoxylin and eosin and were examined immunohistochemically. The duration of follow-up ranged from two years and three months to three years and six months. RESULTS: Expression of amplified carcinoembryonic antigen messenger ribonucleic acid in tumor-draining vein blood was positive in 16 (43 percent) of the 37 patients, while that in the feeding artery blood was positive in 3 patients (8 percent). There was no relation between the protein level of carcinoembryonic antigen and positive expression of carcinoembryonic antigen messenger ribonucleic acid. Positive expression of carcinoembryonic antigen messenger ribonucleic acid was observed in two patients with histologic evidence of massive venous invasion and in all three patients with synchronous liver metastasis. Immunohistochemical studies revealed that all tumor specimens with stromal type (5/5) of carcinoembryonic antigen staining had positive expression of carcinoembryonic antigen messenger ribonucleic acid. Postoperative liver metastasis was detected in four patients, three of whom (75 percent) had positive expression of carcinoembryonic antigen messenger ribonucleic acid in tumor-draining vein blood. CONCLUSIONS: Positive expression of carcinoembryonic antigen messenger ribonucleic acid in tumor-draining vein blood differed by the type of immunohistochemical staining with carcinoembryonic antigen. These data suggest that patients with positive expression of carcinoembryonic antigen messenger ribonucleic acid in tumor-draining vein blood may be at a high risk for postoperative liver metastasis.

Aged↗
PubMed1991

Inhibin subunits in human placenta: localization and messenger ribonucleic acid levels during pregnancy.

This study describes the difference in distribution and levels of inhibin alpha, beta A- and beta B-subunit messenger ribonucleic acids in human placenta during pregnancy. Northern blot analysis indicated that inhibin alpha messenger ribonucleic acid is present in placental extracts collected at the early stage of gestation. Hybridization to inhibin beta A messenger ribonucleic acid was detected in the first trimester but in much lower levels. However, the intensity of the hybridization signal for inhibin alpha- and beta A-subunit messenger ribonucleic acids was greater in extracts prepared from term placentas than in those from the first or second trimester of pregnancy. Low levels of inhibin beta B-subunit messenger ribonucleic acid were observed only in extracts prepared from term placenta. At both early stage and term gestation trophoblast cells showed a positive fluorescent signal with the inhibin alpha-, beta A- and beta B-subunit-specific antisera. However, whereas inhibin alpha-subunit was localized in the cytotrophoblast, inhibin beta B-subunit immunoreactivity was observed in the syncytial layer of the villi, and inhibin beta A-subunit was widely distributed. The different distribution of immunoreactive inhibin subunits was confirmed by in situ hybridization, showing the different localizations of the inhibin messenger ribonucleic acids. These results showed that (1) human placenta produces the inhibin alpha- and beta A-subunits as early as the first trimester of pregnancy, (2) messenger ribonucleic acid levels for each of the three inhibin subunits are highest at term, and (3) immunoreactive inhibin subunits are localized differently in placental villi.

Female↗
PubMed1981

In vivo and in vitro effects of xenogeneic immune ribonucleic acid in patients with advanced renal cell carcinoma: a phase I study.

Based upon demonstration in our laboratory of repeated prevention of pulmonary metastases by adjuvant immune ribonucleic acid in animal preparations, xenogeneic immune ribonucleic acid was given in a phase I study to patients with advanced renal cell carcinoma. Six patients were treated with intravenous infusions of autologous lymphocytes incubated in vitro with immune ribonucleic acid extracted from splenocytes of guinea pigs immunized with the patient's own tumor. Serial peripheral blood lymphocytes were obtained during and after each treatment with immune ribonucleic acid for in vitro evaluation of cell-mediated cytolysis by 51chromium release assay and 125iodine iododeoxyuridine assay against allogeneic renal cell carcinoma targets and melanoma targets. Neither toxicity nor enhancement of tumor growth was observed. All patients demonstrated significantly increased cell-mediated cytolysis against allogeneic renal cell carcinoma targets but no change against melanoma targets. Increased cell-mediated cytolysis could be demonstrated in individual blood samples after incubation with immune ribonucleic acid. Further, progressive in vivo effect was demonstrated in in vitro assay of serial peripheral blood lymphocytes before each successive exposure to immune ribonucleic acid. Increased cell-mediated cytolysis persisted in peripheral blood lymphocytes up to 9 months after therapy. Although without controls 1 patient had complete response and 2 patients had partial responses (8 to 18 months). Two patients had stabilization of the disease for 3 to 4 months and 1 patient had progression of cerebral metastases. One patient is alive 24 months after therapy. These results would favor the institution of a randomized prospective trial in patients with advanced renal cell carcinoma or lesser tumor burdens.

Adenocarcinoma↗
PubMed1999

Expression of adenosine triphosphate-sensitive potassium channel subunits in female rat reproductive tissues: overlapping distribution of messenger ribonucleic acid for weak inwardly rectifying potassium channel subunit 6.1 and sulfonylurea-binding regulatory subunit 2.

OBJECTIVE: Potassium channel activation has been shown to decrease uterine tone and is a target for inhibition of uterine activity in the treatment of preterm labor. In addition, potassium channel activation also appears to be involved in oocyte maturation. The specific potassium channels responsible for these channel currents have not been identified but are known to be responsive to such agents as pinacidil and to be inhibited by glibenclamide. These findings suggest the presence of an adenosine triphosphate-sensitive potassium channel that is a complex of a weak inwardly rectifying potassium channel subunit 6.1 or 6.2 and sulfonylurea-binding regulatory subunit 1 or 2. STUDY DESIGN: The technique of reverse transcriptase-polymerase chain reaction was used to detect the presence of messenger ribonucleic acid for sulfonylurea-binding regulatory subunit 1 and 2 and weak inwardly rectifying potassium channel subunit 6.1 and 6.2 in the ovary and myometrium of the pregnant rat. In situ hybridization histochemical analysis was used to identify the specific cell types expressing each messenger ribonucleic acid. RESULTS: Reverse transcriptase-polymerase chain reaction analysis found expression of messenger ribonucleic acid for sulfonylurea-binding regulatory subunits 1 and 2B and messenger ribonucleic acid for weak inwardly rectifying potassium channel subunit 6.1 in rat myometrium and ovary during gestation. There was no evidence for expression of weak inwardly rectifying potassium channel subunit 6.2 messenger ribonucleic acid in the ovary or the myometrium of the pregnant rat. In situ hybridization histochemical examination localized expression of messenger ribonucleic acid for sulfonylurea-binding regulatory subunit 2B and messenger ribonucleic acid for weak inwardly rectifying potassium channel subunit 6.1 to uterine myocytes and granulosa cells of the corpus luteum. The cells expressing sulfonylurea-binding regulatory subunit 1 messenger ribonucleic acid could not be identified because of the scarcity of this messenger ribonucleic acid. Messenger ribonucleic acid for sulfonylurea-binding regulatory subunit 1, messenger ribonucleic acid for sulfonylurea-binding regulatory subunit 2B, and messenger ribonucleic acid for weak inwardly rectifying potassium channel subunit 6.1 were also observed in the placenta by in situ hybridization histochemical examination. CONCLUSION: The results suggest that the major adenosine triphosphate-sensitive potassium channel expressed in the myometrium and the corpus luteum during pregnancy is a complex of sulfonylurea-binding regulatory subunit 2B and weak inwardly rectifying potassium channel subunit 6.1.

ATP-Binding Cassette Transporters↗
PubMed1981

Multiple forms of lysyl-transfer ribonucleic acid synthetase in Escherichia coli.

Lysyl-transfer ribonucleic acid synthetase (EC 6.1.1.6) was identified as four polypeptide spots after two-dimensional polyacrylamide gel electrophoresis of whole-cell lysates of Escherichia coli. Identification was made by migration with partially purified enzyme preparations, by peptide map patterns, by mutant analysis, and by correlation of spot intensities with changes in enzyme levels under different growth conditions. Wild-type cells growing at 37 degrees C in glucose minimal medium displayed the enzyme predominantly as two spots (spots I and III). Growth at 46 degrees C, growth in the presence of alanine or glycyl-L-leucine, or growth of a strain with a mutational deficiency in S-adenosylmethionine synthetase (metK) greatly increased the synthesis of two other spots (spots II and IV). Polypeptides I and III, but not polypeptides II and IV, had altered isoelectric points in a lysyl-transfer ribonucleic acid synthetase mutant. These data suggest that multiple forms of lysyl-transfer ribonucleic acid synthetase exist in vivo and that they may be encoded by more than one gene.

Amino Acyl-tRNA Synthetases↗
PubMed1959

Nuclear-cytoplasmic relationships in human cells in tissue culture. III. Auto-radiographic study of interrelation of nuclear and cytoplasmic ribonucleic acid.

The movement of ribonucleic acid (RNA) from nucleus to cytoplasm has been studied, by autoradiographic techniques, in cells of the human amnion grown in tissue culture. Cells were exposed to cytidine-H(3) for 1 hour after which time only the RNA of the nuclei was labelled. After this 1 hour exposure the cells were placed in a medium containing an excess amount of unlabelled cytidine. Periodically, cells from this medium were fixed. Autoradiographs showed that there was a progressive movement of the label from nucleus to cytoplasm, such that after 24 hours essentially all the label was in the RNA of the cytoplasm. A study of the incorporation of the cytidine-H(3) in deoxyribonucleic acid (DNA), in the same population of cells at the same times, indicated that the presence of excess amounts of unlabelled cytidine almost instantaneously inhibited further utilization of cytidine-H(3). It is concluded that RNA moves from nucleus to cytoplasm as a complex polynucleotide structure.

Cell Nucleus↗
PubMed1965

PROTEIN AND NUCLEIC ACID SYNTHESIS IN TWO MUTANTS OF ESCHERICHIA COLI WITH TEMPERATURE-SENSITIVE AMINOACYL RIBONUCLEIC ACID SYNTHETASES.

Eidlic, Lia (Purdue University, Lafayette, Ind.), and Frederick C. Neidhardt. Protein and nucleic acid synthesis in two mutants of Escherichia coli with temperature-sensitive aminoacyl ribonucleic acid synthetases. J. Bacteriol. 89:706-711. 1965.-Two temperature-sensitive mutants of Escherichia coli were isolated which grow almost normally at 30 C and fail to grow at 37 C. One (I-9) was derived from a strain with stringent amino acid control of ribonucleic acid (RNA) synthesis; the other (IV-4) was derived from a strain with relaxed amino acid control of RNA synthesis. When cultures of these mutants growing at 30 C were shifted to 37 C, IV-4 synthesized RNA preferentially to protein but I-9 did not. Cell-free extracts of both mutants and their parent strains were examined for their ability to catalyze adenosine triphosphate (ATP)-dependent attachment of amino acids to soluble RNA (sRNA). These measurements indicated that I-9 possesses a temperature-sensitive valyl sRNA synthetase, and that IV-4 possesses a temperature-sensitive phenylalanyl sRNA synthetase. The behavior of these mutants suggests that amino acids permit RNA synthesis in stringent strains only after activation or attachment to sRNA, that relaxed strains can overproduce RNA without a complete array of fully functioning aminoacyl sRNA synthetases, and that these enzymes are obligatory for the biosynthesis of proteins.

Amino Acids↗
PubMed1979

Cellular uptake of ribonucleic acids entrapped into liposomes.

Ribonucleic acids were entrapped into phospholipid vesicles (liposomes). After incubation of the liposomes containing RNA (L- RNA), the RNA was introduced into the cells. The kinetics of L- RNA uptake by the cells in culture were studied. The uptake of L- RNA is linear over a broad vesicle concentration range depending on temperature, and at 37 degrees C uptake levels reach a plateau after 3 hours. Inhibitors of cellular energy metabolism have little effect on the uptake, and thus fusion, as the main mechanism of uptake, is proposed.

Acetates↗
PubMed1976

Characterization of the association of specific proteins with messenger ribonucleic acid.

Isolation of messenger ribonucleic acid (mRNA)-protein particles from cytosol or dissociated polyribosomes yielded complexes in which several proteins were consistently associated with mRNA. Some of the mRNA-associated proteins appeared to have a high affinity for mRNA since they remained complexed to mRNA during centrifugation in CsCl gradients. Quantitation of RNA and protein in polyribosomal mRNPs suggested that each molecule of mRNA bound a molecule of each of the two major proteins of 78 000 and 52 000 apparent molecular weights and/or one or more of several minor proteins found in mRNPs. Of the several mRNP proteins, only the protein of 78 000 apparent molecular weight appeared to form a stable complex with the polyriboadenylic acid [poly(A)]-tract of mRNA, suggesting that the remaining mRNA-associated proteins bind to other regions which may be common to many or all mRNAs. Binding of [3H]poly(A)-rich RNA to mRNP proteins was effectively inhibited by unlabeled poly(A)-rich RNA or the homopolymer polyriboguanylic acid [poly(G)], but not by poly(A) or other natural or synthetic mRNAs. The properties of non-poly(A)-dependent binding of mRNA by mRNP protein were similar to those of mRNA binding by the guanosine triphosphate dependent Met-tRNAfMet-binding protein.

Animals↗