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Biomedical subjects

F Moreno

Publications and source records attributed to F Moreno.

At least 145 records · Page 8Linked to original sources
PubMed1996

dacD, an Escherichia coli gene encoding a novel penicillin-binding protein (PBP6b) with DD-carboxypeptidase activity.

In the course of a study of genes located at min 44 of the Escherichia coli genome, we identified an open reading frame with the capacity to encode a 43-kDa polypeptide whose predicted amino acid sequence is strikingly similar to those of the well-known DD-carboxipeptidases penicillin-binding proteins PBP5 and PBP6. The gene product was shown to bind [3H]benzylpenicillin and to have DD-carboxypeptidase activity on pentapeptide muropeptides in vivo. Therefore, we called the protein PBP6b and the gene dacD. As with other E. coli DD-carboxypeptidases, PBP6b is not essential for cell growth. A quadruple dacA dacB dacC dacD mutant was constructed and shown to grow as well as its isogenic wild-type strain, indicating that the loss of any known PBP-associated DD-carboxypeptidase activity is not deleterious for E. coli. We also identified the homologous gene of dacD in Salmonella typhimurium as one of the components of the previously described phsBCDEF gene cluster.

Amino Acid Sequence↗
PubMed1996

Linkage disequilibrium between four intragenic polymorphic microsatellites of the NF1 gene and its implications for genetic counselling.

Four intragenic polymorphic microsatellite markers, AAAT Alu repeat, IVS27AC28.4, ACI27.2, and IVS38GT53.0, located along a 65 kb DNA region of the NF1 gene, were used to genotype 64 Spanish families with neurofibromatosis type 1 (NF1). Linkage disequilirium between each pair of markers was evaluated. Three of these markers, AAAT Alu repeat, ACI27.2, and IVS38GT53.0, exhibit linkage disequilibrium between each other. Analysis of extended haplotypes provides further evidence of the disequilibrium within this region since only 11 haplotypes account for 52% of the total chromosomes. Because of linkage disequilibrium, the informativeness of marker combinations for genotyping of NF1 families is diminished. There was no difference in the overall distribution of alleles between affected and normal chromosomes. An at risk haplotype was not found, as expected for a disease with at least 50% of cases being sporadic.

Alleles↗
PubMed1996

Structural changes of beta-lactoglobulin B induced by urea. Evidence of residual structure.

Several spectroscopic methods have been used to study the structure of beta-lactoglobulin B at pH 2.1 in the presence of 8M urea. Fluorescence and polarization of fluorescence spectroscopy measurements indicate that the two tryptophanyl residues of the protein are exposed to the solvent in the denatured state. CD in the far-UV indicates that the amount of secondary structure in the denatured state is comparable to that found in the native state, whereas the CD spectrum in the near-UV shows that the tertiary structure is not completely disordered. The results of one-dimensional 1H NMR spectroscopy show that some local non-random structure is maintained in the denatured state, but most of the polypeptide chain has an extended non-globular conformation under the conditions of the present experiments. This conclusion is reinforced by the results of two-dimensional 1H NMR conducted on denatured samples of beta-lactoglobulin B. The study of states with intermediate levels of order will aid the understanding of how the native structure of beta-lactoglobulin B is organised during the refolding pathways.

Animals↗
PubMed1996

Anaphylaxis to penicillins after non-therapeutic exposure: an immunological investigation.

BACKGROUND: There are instances where individuals may come into contact with penicillins without being aware of it. This non-therapeutic exposure from different sources may cause sensitization and even clinical manifestations in subjects allergic to penicillins. OBJECTIVE: To determine the capacity that inadvertent contact with penicillins may have in inducing resensitization and symptoms in patients diagnosed as allergic to penicillins who were followed over a long period of time after their initial evaluation. METHODS: A follow-up study of penicillin-allergic subjects who agreed to be regularly tested for in vitro and in vivo control of their sensitivity. Skin tests were carried out with major and minor determinants of benzylpenicillin (BPO and MDM), amoxicillin (AX), and ampicillin (AMP), and specific IgE antibodies were determined by radioallergosorbent test (RAST). A questionnaire was sent to and answered by the subjects in order to see if they experienced symptoms at any time during the follow-up period. In addition, if any unexplained symptoms occurred, a bleeper system was used to contact the allergy centre. RESULTS: Seven subjects experienced anaphylactic reactions with no obvious cause. At the time of their initial allergic reaction, which was caused by exposure to prescribed penicillin, the subjects had one or more positive skin tests and/or RAST results to penicillin related reagents. However, over the following 2-4 years all their tests became negative. After reporting their unexplained reaction all seven had one or more positive skin tests and/or RAST results again and when retested 1 week later RAST measurements showed that levels of penicillin-specific IgE were maintained or increased. None of the subjects had knowingly received penicillin but the questionnaire showed that six had been exposed to it and in the seventh case exposure was likely. In two cases contact was by sexual intercourse with a partner who was receiving penicillin, three subjects had handled penicillin formulations and one had drunk from a glass previously used for giving penicillin. In the seventh case exposure could have occurred whilst in hospital for surgery, although this was not proven. CONCLUSIONS: these results show that non-therapeutic exposure to penicillin can cause severe symptoms and that in vitro and in vivo testing can help in the diagnosis of such cases.

Adult↗
PubMed1996

Hemangiomas of the head, neck, and chest with associated vascular and brain anomalies: a complex neurocutaneous syndrome.

PURPOSE: To describe the vascular and nonvascular intracranial and extracranial anomalies associated with hemangiomas and vascular malformations of the face, neck, and/or chest. METHODS: Seventeen patients had a physical examination and imaging studies consisting of one or more of the following: pneumoencephalography, conventional carotid and vertebral arteriography, CT, MR imaging, and MR angiography. RESULTS: Conventional arteriography revealed persistence of the trigeminal artery in 5 cases, absence of internal or external carotid and/or vertebral arteries in 11 cases, persistence of intervertebral arteries in 1 case, deformities of the aortic arch in 3 cases, and anomalies of the intracranial arteries in 3 cases. MR angiography revealed persistence of the trigeminal artery in 1 case in which conventional arteriography failed to show the malformation, and permitted visualization of narrowing of the intracranial arteries. CT and MR imaging showed a cerebellar anomaly in 8 cases and cerebral cortical dysplasia with cerebral hemispheric hypoplasia in 1 case. Vascular and nonvascular anomalies appeared ipsilateral to the external vascular abnormalities in most cases. CONCLUSION: This study demonstrates the association of cutaneous angiomas with anomalies affecting intracranial and extracranial arteries, the cerebellum, and, less frequently, the cerebral hemispheres and aortic arch. This association constitutes a relatively frequent neurocutaneous disorder, which we call the cutaneous hemangioma-vascular complex syndrome.

Abnormalities, Multiple↗
PubMed1996

[A case of benign cutaneous polyarteritis nodosa].

Cutaneous polyarteritis nodosa is a benign form of the disease with cutaneous involvement and occasional systemic manifestations. We report a 51 years old man presenting with malaise, arthralgia, myalgia and nodular, erythematous and painful skin lesions in both legs. The pathological study of these lesions showed a polyarteritis. During hospital stay there was a mild remission of the disease without treatment, but its reappearance during follow lead to the use of prednisone.

Humans↗
PubMed1996

[Paternity determination in cases of incest using multiallelic loci DNA polymorphisms].

The analysis of genetic markers in man allows to efficiently resolve cases of dubious paternity. Lately, the use of genetic markers derived from DNA analysis allows high exclusion probabilities. A particular case are those consultations whom the progenitors are closely related, in which the criteria to attribute paternity are modified. The present report explains the analysis methods and interpretation of results in situations of doubtful paternity in cases of incest between father and daughter, using monolocus DNA polymorphisms. The method is illustrated through the analysis of four cases seen at the Servicio Médico Legal of Santiago. To be able to determine paternity in these cases of incest, at least three multiallelic loci in which mother and son have different genotypes must be examined.

Alleles↗
PubMed1995

Incomplete recanalization as an important determinant of Thrombolysis in Myocardial Infarction (TIMI) grade 2 flow after thrombolytic therapy for acute myocardial infarction. TEAM Investigators. Thrombolytic Trial of Eminase in Acute Myocardial Infarction.

The outcome of patients with Thrombolysis in Myocardial Infarction (TIMI) trial grade 2 flow is worse than that of patients with TIMI grade 3 flow after thrombolytic therapy for acute myocardial infarction. It is unclear whether TIMI grade 2 flow represents incomplete recanalization of the culprit lesion or poor distal runoff. The Thrombolytic Trial of Eminase (anistreplase) in Acute Myocardial Infarction (TEAM)-2 and TEAM-3 were randomized trials comparing anistreplase with streptokinase (TEAM-2, n = 370) or with alteplase (tissue plasminogen activator) (TEAM-3, n = 325). We compared the minimal luminal diameter of the culprit lesion in patients with TIMI grade 2 flow with that in patients with TIMI grade 3 flow both 90 minutes (TEAM-2) and 1 day (TEAM-3) after thrombolysis. Patients with TIMI grade 2 flow had a lower residual luminal diameter in the culprit lesion than patients with TIMI grade 3 flow (TEAM-2, 0.58 +/- 0.03 vs 0.79 +/- 0.02 mm, p = 0.0001; TEAM-3, 0.88 +/- 0.04 vs 1.17 +/- 0.03 mm, p = 0.0001, for patients with TIMI grades 2 and 3 flow). Residual percent stenosis was correspondingly higher in patients with TIMI grade 2 flow. At the early angiogram, 66% of patients with TIMI grade 2 flow, but only 35% of those with TIMI grade 3 flow, had a minimal luminal diameter of 0.6 mm (positive predictive value 87%, negative predictive value 35%). Incomplete recanalization of the culprit lesion may thus be an important determinant of TIMI grade 2 flow after thrombolysis. Whether more complete thrombolysis or rescue angioplasty improves outcome in these patients deserves evaluation.

Analysis of Variance↗
PubMed1995

Chemical structure and translation inhibition studies of the antibiotic microcin C7.

Escherichia coli microcin C7 (MccC7) is an antibiotic that inhibits protein synthesis in vivo. It is a heptapeptide containing unknown modifications at the N and C termini (García-Bustos, J. F., Pezzi, N., and Méndez, E. (1985) Antimicrob. Agents Chemoth. 27, 791-797). The chemical structure of MccC7 has been characterized by use of 1H homonuclear and heteronuclear (13C, 15N, 31P) nuclear magnetic resonance spectroscopy as well as mass spectrometry (1177 +/- 1 Da). The heptapeptide Met-Arg-Thr-Gly-Asn-Ala-Asp is substituted at the N terminus by a N-formyl group. The C-terminal substituent consists of the phosphodiester of 5'-adenylic acid and n-aminopropanol (AMPap), which is linked via the phosphorus atom to an amide group, thus forming a phosphoramide. The main chain carbonyl of the C-terminal aspartic acid residue is connected via this amide bond to the modified nucleotide unit. MccC7 and the peptide unit inhibit protein translation in vitro while a synthetic analog of the AMPap substituent is not active. Neither the peptide nor the AMPap molecule has an effect on the growth of MccC7-sensible cells. Our results strongly suggest that the peptide is responsible for MccC7 antibiotic activity while the C-terminal substituent is needed for MccC7 transport. Implications of the structure determined in this work for MccC7 synthesis and mode of action are discussed.

Amino Acid Sequence↗
PubMed1995

Glucose-induced inactivation of isocitrate lyase in Saccharomyces cerevisiae is mediated by an internal decapeptide sequence.

In this work we have investigated the role of specific peptide sequences for glucose-inactivation of the yeast isocitrate lyase. Thus, different fragments of the ICL1 coding region were fused to the lacZ gene of E. coli to provide a reporter construction. Determinations of beta-galactosidase activities indicated that the decapeptide sequence KTKRNYSARD, located between amino acid residues 37 and 46 of isocitrate lyase, is important for glucose induced proteolytic inactivation. Further experimental evidence was provided by insertion of this sequence into a glucokinase-beta-galactosidase fusion protein, which is not sensitive to glucose regulation. The decapeptide inserted conferred glucose inactivation to this construct, confirming that it is both necessary and sufficient as a signal.

Amino Acid Sequence↗
PubMed1995

The early stimulation of glycolysis by epidermal growth factor in isolated rat hepatocytes is secondary to the glycogenolytic effect.

We have studied the relationship between the effect of epidermal growth factor (EGF) on glycogen metabolism and its effect on glycolysis, in rat hepatocyte suspensions. Although 10 nM glucagon or 10 microM adrenaline increased glycogen degradation by more than 120%, 10 nM EGF increased glycogenolysis by less than 20% in hepatocytes incubated in glucose-free medium. Both glucagon and adrenaline increased phosphorylase a activity by more than 130%; EGF increased this activity by about 30%. Under basal conditions, 65% of the glucosyl residues were released as free glucose and about 30% ended up as C3 molecules (lactate and pyruvate). Both glucagon and adrenaline decreased the proportion of glucosyl units that rendered glycolysis end-products (to 2% for glucagon and 6% for adrenaline) and increased the proportion that ended up as free glucose (to 94% and 88% of the glucosyl residues for glucagon and adrenaline respectively). EGF increased the production of both free glucose and lactate+pyruvate, but the proportion of glucosyl residues that ended up as free glucose or glycolysis end-products was unchanged. In glycogen-depleted hepatocytes incubated in the presence of 25 mM glucose, EGF affected neither glycogen deposition nor glycolysis. EGF increased cytosolic free Ca2+, and neomycin decreased both the Ca2+ signal and the glycogenolytic effect. In conclusion, our results indicate that the effect of EGF on glycolysis is secondary to the Ca(2+)-mediated stimulation of glycogenolysis in rat hepatocyte suspensions.

Animals↗
PubMed1995

Mulibrey nanism: three additional patients and a review of 39 patients.

We report on 3 patients with Mulibrey nanism (MN), or Perheentupa syndrome: the first 2 sibs from Argentina and a new patient from Spain. All 3 patients had growth failure, short stature, abnormal pigmentary retinal changes, and a J-shaped sella turcica. These findings are considered major criteria of MN. Two had pericardial constriction, which is a frequent and life-threatening abnormality in this syndrome. MN is a rare autosomal recessive condition. Reviewing the 39 patients described so far, we have classified the anomalies into the very frequent (present in more than 66%), frequent (in at least 25%), and not frequent. Identifying the anomalies specific to MN should help its early diagnosis and treatment.

Abnormalities, Multiple↗
PubMed1995

Transcriptional regulation of the Saccharomyces cerevisiae HXK1, HXK2 and GLK1 genes.

In Saccharomyces cerevisiae, the transcriptional regulation of most glycolytic genes has been extensively studied. By contrast, little is known about the transcriptional control of the three glucose-phosphorylating enzymes, although this catalytic reaction has an important role in the regulation of cell metabolism. In this paper, we describe the transcriptional regulation of the HXK1, HXK2 and GLK1 genes in the hope of revealing differences in the steady-state levels of mRNA associated with a particular carbon source used in the culture medium. Our results provide evidence supporting a differential expression of the three genes depending on the carbon source used for growth. We have also studied the induction and repression kinetics of mRNA expression for the HXK1, HXK2 and GLK1 genes.

Gene Expression Regulation, Enzymologic↗
PubMed1995

Use of serial carcinoembryonic antigen and CA 15.3 assays in detecting relapses in breast cancer patients.

UNLABELLED: To evaluate the utility of CEA and CA 15.3 for early diagnosis of recurrence, serial serum determinations of both antigens were performed in 1023 patients (follow-up: 1-10 years, mean 6.2 years) with primary breast cancer (CA 15.3 in 533 cases) and no evidence of residual disease (NED) after radical treatment (radical mastectomy or simple mastectomy and radiotherapy). 246 patients developed metastases during follow-up. RESULTS: CEA and CA 15.3 were elevated ( > 10 ng/ml or > 60 U/ml, respectively) prior to diagnosis in 40% (98/246) and 41% (37/91) of the patients with recurrence, with a lead time of 4.9 +/- 2.2 and 4.2 +/- 2.3 months, respectively. When patients with locoregional recurrences were excluded, sensitivity improved to 46% (CEA) and 54% (CA 15.3), and to 64% with both tumor markers (CEA and/or CA 15.3). Higher levels of both CEA and CA 15.3 at diagnosis of recurrence, higher sensitivity in early diagnosis of relapse, and a higher lead time were found in ER+ (CEA) or PgR+ patients (CA 15.3) than in those that were negative for these receptors in the primary tumor (p < 0.001). Specificity of the tumor markers was 99% for both CEA (777 NED patients) and for CA 15.3 (444 NED patients), respectively. In conclusion, CEA and CA 15.3 are useful tools for early diagnosis of metastases, mainly in those patients with ER+ or PR+ tumors.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1995

Microcins.

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Amino Acid Sequence↗
PubMed1995

Clinical and molecular epidemiology of vancomycin-resistant Enterococcus faecium during its emergence in a city in southern Texas.

During a 19-month period from April 1993 to October 1994, 41 isolates of vancomycin-resistant Enterococcus faecium (VREF) were detected in seven different hospitals in a city in southern Texas. A case-control study to determine the risk factors for acquisition was done in the hospital in which the majority of isolates were detected. Pulsed-field gel electrophoresis (PFGE) of whole-cell DNA was used to determine strain identity. Thirty-five (85%) of the 41 VREF isolates were of the vanB phenotype. Of these, 32 (91%) of 35 were the same strain by PFGE typing. The same vanB strain was documented in five different hospitals in the city. In contrast, 4 (67%) of 6 of the vanA phenotype VREF isolates were distinct strains by PFGE typing. Significant risk factors for colonization or infection with VREF were prior exposure to antibiotics (P = .04), the previous use of third-generation cephalosporins (P = .03), and the previous use of parenteral vancomycin (P = .002). Infection-control and antibiotic-utilization measures were implemented to control cross-transmission and selection of VREF isolates. During the emergence of VREF in our city, clonal dissemination of a single strain of vanB VREF among six hospitals was documented. Limited cross-transmission of vanA phenotype VREF isolates occurred, but most vanA VREF isolates were distinct strains selected in individual hospital environments.

Anti-Bacterial Agents↗