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Biomedical subjects

F Moreno

Publications and source records attributed to F Moreno.

At least 217 records · Page 12Linked to original sources
PubMed1991

A hisT::Tn5 mutation affects production of microcins B17, C7, and H47 and colicin V.

A Tn5 insertion decreasing the production of microcin B17 was mapped to 50.2 min on the Escherichia coli chromosome map. Sequence analysis showed that the insertion disrupted hisT, the gene encoding pseudouridine synthase I, a tRNA-modifying enzyme. hisT::Tn5 mutant cells were also shown to be defective for the production of other antibiotic peptides, such as microcin C7, microcin H47, and colicin V.

Amino Acid Sequence↗
PubMed1990

[Medical counseling, nursing counseling, and nicotine chewing gum for smoking cessation in primary care].

The 2-month results of a study designed to compare the effectiveness of three methods to encourage giving up smoking in primary health care are reported: individualized medical counseling (minimal intervention), counseling plus follow-up option by the nurse, and medical counseling plus nicotine chewing gum. Overall 425 smokers between 15 and 65 years of age were included in the study. In 349 of them (82%), short term follow-up was carried out by phone interview. The proportion who declared to have given up smoking, after adjustment for the estimated validity of the phone report of smoking status, was 10, 9%, 10.8% and 11.1%, respectively, without significant differences between the three groups. In the logistic regression analysis, only the existence of concomitant disease and the anticipated difficulty in giving up smoking appeared as predictive variables of abstention. The implications of the results for the strategies to control smoking are discussed.

Adolescent↗
PubMed1990

Does an adequate control of blood pressure protect the kidney in essential hypertension?

We analyzed the clinical course of 120 patients who were diagnosed as having primary hypertension and subsequently given standard stepped-care therapy (diuretic, beta-blocker and vasodilator) for 9 years. At the end of the follow-up period, 21 patients (17.5%) had developed overt proteinuria. The initial study showed no difference in systolic blood pressure, age, sex, serum creatinine and its clearance, glucose, cholesterol and triglycerides between these patients and those who had not become proteinuric, but uric acid levels and diastolic blood pressure were higher (both P less than 0.01). An adequate control of blood pressure was obtained and maintained in all patients, who had similar therapeutic needs. During the follow-up period, uric acid levels remained significantly elevated (P less than 0.01) in the proteinuric patients, while changes in serum glucose, cholesterol and triglycerides were similar in all patients. These results indicate that long-term treatment of primary hypertensives does not fully protect kidney function and that initially elevated uric acid levels could be a predictor of a poor prognosis.

Adrenergic beta-Antagonists↗
PubMed1990

Molecular characterization of pmbA, an Escherichia coli chromosomal gene required for the production of the antibiotic peptide MccB17.

Microcin B17 (MccB17) is a peptide antibiotic produced by Escherichia coli strains harbouring plasmid pMccB17. We have isolated two mutations that strongly reduce the production of MccB17. These mutations, which map at 96 min on the E. coli chromosome, define a new gene that we have called pmbA. A chromosomal DNA fragment of about 13 kb, including the wild-type pmbA allele, was cloned into a mini-Mu plasmid vector. pmbA was located within the cloned DNA fragment by insertional mutagenesis and deletion analysis. The nucleotide sequence of a 1.7 kb DNA region containing the gene was determined. pmbA encodes a hydrophilic protein of 450-amino-acid residues with a predicted molecular size of 48375D, which was visualized in polyacrylamide gels. Protein profiles of cellular envelope and soluble fractions from cells with plasmids overproducing PmbA indicated that it is cytoplasmic. Physiological experiments suggested that pmbA mutants synthesize a molecule (pro-MccB17) able to inhibit DNA replication but unable to be released from cells. We propose that PmbA facilitates the secretion of the antibiotic by completing its maturation.

Amino Acid Sequence↗
PubMed1990

mprA, an Escherichia coli gene that reduces growth-phase-dependent synthesis of microcins B17 and C7 and blocks osmoinduction of proU when cloned on a high-copy-number plasmid.

Microcins B17 and C7 are plasmid-determined, peptide antibiotics produced by Escherichia coli when cells enter the stationary phase of growth. Microcinogenic strains are immune to the action of the microcin they synthesize. A well-characterized deficient-immunity phenotype is exhibited by microcin B17-producing cells in the absence of the immunity gene mcbG (M.C. Garrido, M. Herrero, R. Kolter, and F. Moreno, EMBO J. 7:1853-1862, 1988). A 14.6-kilobase-pair EcoRI chromosomal fragment was isolated by its ability to suppress this phenotype when cloned into a multicopy vector. This fragment was mapped to 57.5 min on the E. coli genetic map. The position of the gene responsible for suppression, designated mprA, was determined by insertional mutagenesis and deletion analysis. mprA was shown to be transcribed clockwise on the E. coli chromosome, and its product was identified as a 19-kilodalton polypeptide. Suppression was shown to be achieved by decreasing microcin B17 production. Increased mprA gene dosage also caused a decrease in microcin C7 production and blocked the osmoinduction of the proU locus in high-osmolarity media. Our results suggest that the mprA gene product could play a regulatory role on expression of several E. coli genes, this control being exerted at the transcriptional level.

Anti-Bacterial Agents↗
PubMed1990

Microcin H47, a chromosome-encoded microcin antibiotic of Escherichia coli.

Microcin H47 (MccH47) is a novel microcin antibiotic produced by a natural Escherichia coli isolate. In contrast to all the other colicins and microcins examined to date, which are plasmid encoded, the genes for MccH47 synthesis and immunity are located on the chromosome. These genetic determinants were cloned and shown to extend over a continuous DNA region of ca. 10 kb.

Anti-Bacterial Agents↗
PubMed1990

Comparison of cetirizine with astemizole in the treatment of perennial allergic rhinitis and study of the concomitant effect on histamine and allergen-induced wheal responses.

Thirty patients suffering from perennial allergic rhinitis took astemizole and cetirizine, 10 mg/d, under double-blind, crossover randomized conditions for 4 weeks. Four weeks washout separated the two periods. Nasal condition was improved, histamine and allergen-induced wheal responses were inhibited by both treatments with a slight advantage for cetirizine. Both treatments were well tolerated.

Adult↗
PubMed1990

Secondary hyperparathyroidism in CAPD patients: its suppressibility with high doses of calcitriol.

Secondary hyperparathyroidism (HP) is well known complication of long-term uremia. CAPD patients show a peculiar behaviour due to loss of vitamin D metabolites through peritoneum. Severe degrees of hyperparathyroidism may require parathyroidectomy in order to achieve appropriate control. Recently, the possibility of controlling this situation with high oral doses of calcitriol has been communicated. The purpose of this study is to evaluate the effect of this agent on hyperparathyroidism in CAPD patients. Two different groups were constituted according to the length of time on dialysis when HP was detected. All of the patients had i-PTH serum levels five times higher than the normal values (50 pg/ml). During a six month period the daily dose of oral calcitriol was increased in order to achieve a reduction in i-PTH level. The results after this period showed a significant reduction in i-PTH levels (614 +/- 378 to 241 +/- 80 pg/ml) with an average increase in oral calcitriol from 0.16 +/- 0.1 to 0.67 +/- 0.4 with no significant changes in serum calcium or phosphorus. The group with HP at start of dialysis achieved these effects easier and with lower doses of calcitriol. We conclude that moderately high doses of oral calcitriol control secondary hyperparathyroidism in CAPD patients without hypercalcemia.

Calcitriol↗
PubMed1990

[Physiological mode of pacing in pediatrics].

The concept of physiologic pacing is often primarily to involve the preservation of atrioventricular synchrony. Nevertheless, specially in children there are other mechanisms different than atrial filling to improve cardiac output such as heart rate increase with exercise. Taking as physiologic pacing those modes of pacing improving hemodynamic condition of the patient we must add to the DDD, the DDDR and SSIR modes of pacing. In this report our experience with 70 consecutive children paced in physiological mode of pacing is described: 51 in SSIR mode, DDD in 16, and DDDR in 3 cases. In five out of the 16 cases with DDD mode it was found an unidirectional crosstalk and in two atrial sensing failure (failure rate with DDD of 47.75% at 48 months of follow-up). In 26 children with rate responsive pacing by means of activity sensing a treadmill exercise test according to Bruce protocol was performed found a significant increase in both, heart rate and maximal work capacity, associated to an improvement in the clinical status and no evidence of arrhythmias in any case. In conclusion, rate responsive pacing by means of activity sensing in children is an adequate, reliable and effective physiological mode of pacing.

Adolescent↗
PubMed1989

Congenital heart block immunogenetics. Evidence of an additional role of HLA class III antigens and independence of Ro autoantibodies.

Congenital complete heart block (CCHB) occurs in the offspring of mothers who have the HLA-A1;B8; DR3 haplotype and Ro (SS-A) autoantibodies. It has been shown that the presence of HLA-DR3 in mothers may facilitate Ro synthesis, but may not, by itself, be sufficient to induce CCHB in the offspring. However, maternal DR3 and Ro antibody seem to be independent factors associated with CCHB. Other HLA antigens, including class III (complement) genes, may also be necessary to induce CCHB in newborns since A1;B8; DR3 haplotypes, together with BfS and/or C4AQ0B1, are increased in Ro+ mothers of infants with CCHB compared with both controls and with Ro+ mothers whose offspring do not have CCHB. On the other hand, DR3 genes in a different HLA haplotype (i.e., B18; BfF1;DR3) are nonpathogenetic; this latter finding may be due to a DR3 gene's intrinsic difference or to the influence of neighboring genes. Also, a trend toward DR3 bias transmission is observed in DR3+ mothers who are also Ro+; fetal DR3 might protect the fetus against in utero death when Ro antibodies are present.

Antibodies, Antinuclear↗
PubMed1989

The hexokinase isoenzyme PII of Saccharomyces cerevisiae ia a protein kinase.

The HXK2 gene product has an important role in controlling carbon catabolite repression in Saccharomyces cerevisiae. We have raised specific antibodies against the hexokinase PII protein and have demonstrated that it is a 58 kDa phosphoprotein with protein kinase activity. The predicted amino acid sequence of the HXK2 gene product has significant homology to the conserved catalytic domain of mammalian and yeast protein kinases. Protein kinase activity was located in a different domain of the protein from the hexose-phosphorylating activity. The hexokinase PII protein level remained unchanged in P2T22D mutant cells (hxk1 HXK2 glk1) growing in a complex medium with glucose. The protein kinase activity of hexokinase PII is regulated by the glucose concentration of the culture medium. Exit from the carbon catabolite repression phase and entry into derepression phase may be controlled, in part, by modulation of the 58 kDa protein kinase activity by changes in cyclic AMP concentration.

Amino Acid Sequence↗
PubMed1989

DNA sequence, products, and transcriptional pattern of the genes involved in production of the DNA replication inhibitor microcin B17.

The 3.8-kilobase segment of plasmid DNA that contains the genes required for production of the DNA replication inhibitor microcin B17 was sequenced. The sequence contains four open reading frames which were shown to be translated in vivo by the construction of fusions to lacZ. The location of these open reading frames fits well with the location of the four microcin B17 production genes, mcbABCD, identified previously through genetic complementation. The products of the four genes have been identified, and the observed molecular weights of the proteins agree with those predicted from the nucleotide sequence. The transcription of these genes was studied by using fusions to lacZ and physical mapping of mRNA start sites. Three promoters were identified in this region. The major promoter for all the genes is a growth phase-regulated OmpR-dependent promoter located upstream of mcbA. A second promoter is located within mcbC and is responsible for a low-level basal expression of mcbD. A third promoter, located within mcbD, promotes transcription in the reverse direction starting within mcbD and extending through mcbC. The resulting mRNA appears to be an untranslated antisense transcript that could play a regulatory role in the expression of these genes.

Amino Acid Sequence↗
PubMed1989

appR gene product activates transcription of microcin C7 plasmid genes.

Microcin C7 (MccC7) is encoded by Escherichia coli plasmid pMccC7. However, some strains of E. coli K-12 carrying this plasmid do not produce this antibiotic. Here we show that these strains differ in the gene locus appR. This chromosomal gene product controls MccC7 production by activating the transcription of some, but not all, MccC7 plasmid genes.

Bacteriocins↗
PubMed1989

Effects of epidermal growth factor (urogastrone) on gluconeogenesis, glucose oxidation, and glycogen synthesis in isolated rat hepatocytes.

Using isolated rat hepatocytes, we studied the effect of epidermal growth factor (urogastrone) (EGF-URO) on the incorporation of [3-14C]pyruvate into glucose and glycogen, on the incorporation of [U-14C]glucose into glycogen, and on the oxidation of [U-14C]glucose to 14CO2. The effects of EGF-URO were compared with those of glucagon and insulin. EGF-URO, with an EC50 of 0.2 nM, enhanced by 34% (maximal stimulation) the conversion of [3-14C]pyruvate into glucose; no effect was observed on the oxidation of glucose to CO2 and on the incorporation of either pyruvate or glucose into glycogen. The effect of EGF-URO on pyruvate conversion to glucose was observed only when hepatocytes were preincubated with EGF-URO for 40 min prior to the addition of substrate. Glucagon (10 nM) increased the incorporation of [3-14C]pyruvate into glucose (44% above control); however, unlike EGF-URO, glucagon stimulated gluconeogenesis better without than with a preincubation period. Neither insulin nor EGF-URO (both 10 nM) affected the incorporation of [U-14C]glucose into glycogen during a 20-min incubation period. However, at longer time periods of incubation with the substrate (60 instead 20 min), insulin (but not EGF-URO) increased the incorporation of [14C]glucose into glycogen; EGF-URO counteracted this stimulatory effect of insulin. In contrast with previous data, our work indicates that EGF-URO can, under certain conditions, counteract the effects of insulin and, like glucagon, promote gluconeogenesis in isolated rat hepatocytes.

Animals↗