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H Rodriguez

Publications and source records attributed to H Rodriguez.

At least 73 records · Page 4Linked to original sources
PubMed1992

An Escherichia coli plasmid-based, mutational system in which supF mutants are selectable: insertion elements dominate the spontaneous spectra.

A new system is described to determine the mutational spectra of mutagens and carcinogens in Escherichia coli; data on a limited number (142) of spontaneous mutants is presented. The mutational assay employs a method to select (rather than screen) for mutations in a supF target gene carried on a plasmid. The E. coli host cells (ES87) are lacI- (am26), and carry the lacZ delta M15 marker for alpha-complementation in beta-galactosidase. When these cells also carry a plasmid, such as pUB3, which contains a wild-type copy of supF and lacZ-alpha, the lactose operon is repressed (off). Furthermore, supF suppression of lacIam26 results in a lactose repressor that has an uninducible, lacIS genotype, which makes the cells unable to grow on lactose minimal plates. In contrast, spontaneous or mutagen-induced supF- mutations in pUB3 prevent suppression of lacIam26 and result in constitutive expression of the lactose operon, which permits growth on lactose minimal plates. The spontaneous mutation frequency in the supF gene is approximately 0.7 and approximately 1.0 x 10(-6) without and with SOS induction, respectively. Spontaneous mutations are dominated by large insertions (67% in SOS-uninduced and 56% in SOS-induced cells), and their frequency of appearance is largely unaffected by SOS induction. These are identified by DNA sequencing to be Insertion Elements; IS1 dominates, but IS4, IS5, gamma-delta and IS10 are also obtained. Large deletions also contribute significantly (19% and 15% for -SOS and +SOS, respectively), where a specific deletion between a 10 base pair direct repeat dominates; the frequency of appearance of these mutations also appears to be unaffected by SOS induction. In contrast, SOS induction increases base pairing mutations (13% and 27% for -SOS and +SOS, respectively). The ES87/pUB3 system has many advantages for determining mutational spectra, including the fact that mutant isolation is fast and simple, and the determination of mutational changes is rapid because of the small size of supF.

Base Sequence↗
PubMed1991

Isolation and characterization of two peptides with prolactin release-inhibiting activity from porcine hypothalami.

Two peptides with in vitro prolactin release-inhibiting activity were purified from stalk median eminence (SME) fragments of 20,000 pig hypothalami. Monolayer cultures of rat anterior pituitary cells were incubated with aliquots of chromatographic fractions and the inhibition of release of prolactin in vitro was measured by RIA in order to monitor the purification. The hypothalamic tissue extract was separated into 11 fractions by high-performance aqueous size-exclusion chromatography with one fraction showing a 4-fold increase in prolactin release-inhibiting factor (PIF) activity. This material was further purified by semipreparative reversed-phase (RP) HPLC. This process resulted in the separation of two distinct fractions that showed high PIF activity. These were further purified by semipreparative and analytical RP-HPLC to apparent homogeneity as judged by the UV absorbance profiles. Neither of the two peptides showed cross-reactivity with gonadotropin releasing hormone-associated peptide or with somatostatin-14 antibodies. Protein sequence analysis revealed that one of the PIF peptides was Trp-Cys-Leu-Glu-Ser-Ser-Gln-Cys-Gln-Asp-Leu-Ser-Thr-Glu-Ser-Asn-Leu-Leu- Ala-Cys - Ile-Arg-Ala-Cys-Lys-Pro, identical to residues 27-52 of the N-terminal region of the proopiomelanocortin (POMC) precursor (corresponding to amino acids 1-26 of the 16-kDa fragment). The sequence of the other PIF was Ala-Ser-Asp-Arg-Ser-Asn-Ala-Thr-Leu-Leu-Asp-Gly-Pro-Ser-Gly-Ala-Leu-Leu- Leu-Arg - Leu-Val-Gln-Leu-Ala-Gly-Ala-Pro-Glu-Pro-Ala-Glu-Pro-Ala-Gln-Pro-Gly-Val- Tyr, representing residues 109-147 of the vasopressin-neurophysin precursor. Synthetic peptides corresponding to the N-terminal region of POMC had significant PIF activity in vitro.

Animals↗
PubMed1991

Fadrozole hydrochloride: a potent, selective, nonsteroidal inhibitor of aromatase for the treatment of estrogen-dependent disease.

A new class of potent, selective, nonsteroidal inhibitors of aromatase have been discovered. The most potent member of this series is fadrozole hydrochloride, CGS 16949 A, 4-(5,6,7,8-tetrahydroimidazo[1,5-alpha]pyridin-5-yl)benzonitrile monohydrochloride, 26a. In addition, the 6,7-dihydropyrrolo[1,2-c]imidazole (21a) and the 6,7,8,9-tetrahydroimidazo[1,5-alpha]azepine (21b) analogues were synthesized and evaluated. CGS 16949 A's ability to selectively inhibit aromatase (IC50 = 4.5 nM) over other cytochrome P-450 enzymes and suppress estrogen production when administered orally make it a suitable candidate to test the potential of an aromatase inhibitor in estrogen-dependent diseases including breast cancer.

Animals↗
PubMed1991

Same-day surgery preparation: reduction of pediatric patient arousal and distress through participant modeling.

Twenty-six children (mean age = 5.5 years) were exposed to one of three surgery preparatory conditions: participant modeling alone (n = 9), participant modeling with mother (n = 8), and standard procedure control (n = 9). Children exposed to the modeling slide-tape without their mothers had significant reductions in physiological arousal after the slide-tape presentation, unlike children viewing the tape with their mothers and children exposed to the control condition. Both participant modeling groups exhibited significantly fewer distressful behaviors during recovery (postsurgery) than did control group children. Results are discussed with respect to previous medical preparation research. Implications of these findings concerning clinical application and future research are addressed.

Ambulatory Surgical Procedures↗
PubMed1990

Genotoxicity of 1-nitropyrene and 2,4,7-trinitro-9-fluorenone to mammalian cells.

Nitroarenes are ubiquitous environmental pollutants displaying potent genotoxicity in bacterial and mammalian cells. In this study, 2,4,7-trinitro-9-fluorenone (TNF) was more potent than 1-nitropyrene (1-NP) in eliciting genotoxic responses in 4 mammalian cell lines. All 4 cell types were capable of activating the nitroarenes, since no special incubation conditions were required. Inhibition of normal DNA synthesis and cytotoxicity were significantly increased with TNF in a dose range of 0.2-5 micrograms/ml for human teratocarcinoma (PA1) cells, mouse Sertoli (TM4) cells, rat hepatoma (RL12) cells, and human-Chinese hamster ovary (CHO-K1) cells. For 1-NP, a dose range of 10-20 micrograms/ml was required to achieve comparable results for the respective cell lines. Only the RL12 and CHO-K1 cells showed recovery of normal DNA synthesis when TNF or 1-NP was removed from the medium. The other cell types showed little or no recovery up to 42 h after removal of the nitroarene. In exclusively studying TNF, the induction of sister-chromatid exchanges (SCEs) and a delay in cell cycle as monitored by harlequin chromosomes, were observed at a concentration range of 0.003-0.2 microgram/ml in PA1, TM4, and RL12 cells. In CHO-K1 cells, TNF at 0.001-1 microgram/ml was clearly mutagenic at the hprt locus.

Animals↗
PubMed1989

Cloning of a lymphocyte homing receptor reveals a lectin domain.

Lymphocytes express cell surface molecules, termed homing receptors, that mediate their selective attachment to specialized high endothelial venules found within secondary lymphoid organs. Previous work has demonstrated that the adhesive interaction between lymphocytes and the endothelium of peripheral lymph nodes appears to involve a lectin-like activity. Moreover, MEL-14, a monoclonal antibody that blocks lymphocyte-peripheral lymph node binding and presumably recognizes the homing receptor mediating this adhesive interaction, appeared to detect the lectin-like receptor. In this paper we describe the cloning of a murine cDNA that encodes the antigen recognized by the MEL-14 antibody. Characterization of the cDNA encoding the putative mouse peripheral lymph node-specific homing receptor shows that it contains a lectin domain that appears to be involved in the binding of lymphocytes to peripheral lymph node endothelium, thus defining a new type of cellular adhesion molecule. This result supports a novel mechanism for the distribution of lymphocyte populations to various lymphoid organs.

Amino Acid Sequence↗
PubMed1989

Nitrogen-fixing cyanobacterium with a high phycoerythrin content.

The elemental and molecular composition, pigment content, and productivity of a phycoerythrin-rich nitrogen-fixing cyanobacterium-an Anabaena strain isolated from the coastal lagoon Albufera de Valencia, Spain-has been investigated. When compared with other heterocystous species, this strain exhibits similar chlorophyll a, carotene, and total phycobiliprotein contents but differs remarkably in the relative proportion of specific phycobiliproteins; the content of C-phycoerythrin amounts to 8.3% (versus about 1% in the other species) of cell dry weight. Absorption and fluorescence spectra of intact phycobilisomes isolated from this Anabaena sp. corroborate the marked contribution of phycoerythrin as an antenna pigment, a circumstance that is unusual for cyanobacteria capable of fixing N(2). The pigment content of cells is affected by variations in irradiance and cell density, these adaptive changes being more patent for C-phycoerythrin than for phycocyanins. The Anabaena strain is clumpy and capable of rapid flocculation. It exhibits outdoor productivities higher than 20 g (dry weight) m day during summer.

Journal Article↗
PubMed1988

The primary structure of aphrodisin.

Aphrodisin is a protein which is secreted in hamster vaginal discharge and acts via the vomeronasal organ of the accessory olfactory system to elicit copulatory behavior in male hamsters. The complete primary structure of aphrodisin was determined by sequence analysis of intact aphrodisin after unblocking the amino terminus with pyroglutamate aminopeptidase and from peptides generated by trypsin and Lys-C digests. Alignment of the peptides was obtained from sequence analysis of peptides from cyanogen bromide and hydroxylamine cleavages. The protein consists of 151 residues of Mr = 17,000. It has disulfide bonds linking cysteine residues at positions 38 and 42 and at 57 and 149. N-acetylglucosamine residues are linked to asparagines at positions 41 and 69. Based on its similarity to the major urinary proteins in rats and mice, aphrodisin is a putative member of the alpha 2u-globulin superfamily of extracellular proteins.

Amino Acid Sequence↗
PubMed1988

Membrane guanylate cyclase is a cell-surface receptor with homology to protein kinases.

Guanylate cyclase has been strongly implicated as a cell-surface receptor on spermatozoa for a chemotactic peptide, and on various other cells as a receptor for atrial natriuretic peptides. Resact (Cys-Val-Thr-Gly-Ala-Pro-Gly-Cys-Val-Gly-Gly-Gly-Arg-Leu-NH2), the chemotactic peptide released by sea urchin Arbacia punctulata eggs, is specifically crosslinked to A. punctulata spermatozoan guanylate cyclase. After the binding of the peptide the state of guanylate cyclase phosphorylation modulates enzyme activity. We report here that the deduced amino-acid sequence of the spermatozoan membrane form of guanylate cyclase predicts an intrinsic membrane protein of 986 amino acids with an amino-terminal signal sequence. A single transmembrane domain separates the protein into putative extracellular and cytoplasmic-catalytic domains. The cytoplasmic carboxyl-terminal 95 amino acids contain 20% serine, the likely regulatory sites for phosphorylation. Unexpectedly, the enzyme is homologous to the protein kinase family.

Amino Acid Sequence↗
PubMed1988

Purification and characterization of the restriction endonuclease RsrI, an isoschizomer of EcoRI.

Rhodobacter sphaeroides strain 630 produces restriction enzyme RsrI which is an isoschizomer of EcoRI. We have purified this enzyme and initiated a comparison with the EcoRI endonuclease. The properties of RsrI are consistent with a reaction mechanism similar to that of EcoRI: the position of cleavage within the -GAATTC-site is identical, the MgCl2 optimum for the cleavage is identical, and the pH profile is similar. Methylation of the substrate sequence by the EcoRI methylase protects the site from cleavage by the RsrI endonuclease. RsrI cross-reacts strongly with anti-EcoRI serum indicating three-dimensional structural similarities. We have determined the sequence of 34 N terminal amino acids for RsrI and this sequence possesses significant similarity to the EcoRI N terminus.

Amino Acid Sequence↗
PubMed1988

Rabbit liver growth hormone receptor and serum binding protein. Purification, characterization, and sequence.

A putative growth hormone receptor from detergent-solubilized rabbit liver membranes and the growth hormone binding protein from rabbit serum have been purified 59,000- and 400,000-fold, respectively, primarily by affinity chromatography. Both purified proteins exhibit high affinity binding for human growth hormone; K alpha = 9-30 x 10(9) M-1 for the liver receptor and K alpha = 6 x 10(9) M-1 for the binding protein. The apparent molecular weight of the liver receptor is 130,000 by reduced sodium dodecyl sulfate gel electrophoresis, while that of the binding protein is 51,000. Both contain N-linked carbohydrate. The amino-terminal sequences of the liver growth hormone receptor and the serum binding protein were found to be the same, indicating that the binding protein corresponds to the extracellular domain of the liver receptor. Ubiquitin was found covalently linked to the liver receptor but not to the serum binding protein. The amino acid sequences of several peptides from the liver receptor were also determined after tryptic and V8 protease digestion.

Animals↗
PubMed1988

Santorinirrhage: hemosuccus pancreaticus in pancreas divisum.

We describe a previously unreported complication of pancreas divisum: severe and repeated episodes of gastrointestinal bleeding through the main pancreatic duct (hemosuccus pancreaticus) in a 34-yr-old woman over a period of 10 months. She had negative investigations, including a blank laparotomy, until an endoscopic retrograde cholangiopancreatography revealed a pancreas divisum with chronic pancreatitis and a small pseudocyst at the tail of the dorsal pancreas. During the procedure, bleeding through the papilla minor was observed coming from Santorini's duct. A corporocaudal pancreatectomy was done and the bleeding episodes have subsided.

Adult↗
PubMed1987

Computer analysis of automated Edman degradation and amino acid analysis data.

Computer programs are described that allow facile analysis of data from a protein sequencer and amino acid analyzer. The sequencer program provides automated sequence interpretation while requiring minimal user interaction. The program serves as a powerful aid in deciphering mixture sequences and allows routine monitoring of sequencer performance. The computer program for amino acid analysis data provides the following calculations: mole percent, protein concentration and residues per mole with comparison between theoretical and calculated values. A plot of molecular weight versus deviation from integer values is calculated providing a measure of peptide or protein purity.

Amino Acids↗
PubMed1987

A parathyroid hormone-related protein implicated in malignant hypercalcemia: cloning and expression.

Humoral hypercalcemia of malignancy is a common complication of lung and certain other cancers. The hypercalcemia results from the actions of tumor factors on bone and kidney. We report here the isolation of full-length complementary DNA clones of a putative hypercalcemia factor, and the expression from the cloned DNA of the active protein in mammalian cells. The clones encode a prepro peptide of 36 amino acids and a mature protein of 141 amino acids that has significant homology with parathyroid hormone in the amino-terminal region. This previously unrecognized hormone may be important in normal as well as abnormal calcium metabolism.

Amino Acid Sequence↗