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Biomedical subjects

F Moreno

Publications and source records attributed to F Moreno.

At least 127 records · Page 7Linked to original sources
PubMed1997

The presence of latex can induce false-positive skin tests in subjects tested with penicillin determinants.

Latex allergens are ubiquitous, and exposure may occur from different sources in the medical environment and in daily life. The observation that subjects with latex allergy were skin test positive to major and minor determinants of penicillins led our group to carry out an investigation to try to explain these findings. A group of 20 subjects with a history of allergy to latex and with positive skin tests for, but good tolerance of, penicillins was studied. The presence of latex contaminants was studied by RAST and RAST inhibition. Sixteen of the subjects were positive to at least one of the penicillin determinants used, and 14 (87%) of these were positive to at least two determinants. Repetition of skin tests using the container without a stopper changed the skin test results to negative in almost all cases, indicating that some trace contaminants had still been present. RAST-inhibition studies showed that in all penicillin determinants there were trace amounts of latex allergens varying between 3 and 0.03 micrograms/ml. These results indicate that skin tests with penicillin in subjects allergic to latex may give false-positive results and lead to such patients being falsely diagnosed as allergic to betalactams when penicillins are stored in containers with rubber stoppers.

Adolescent↗
PubMed1997

[Anatomo-radiologic correlation of the head of the goat of the canary breed (Capra hircus L.)].

A radiologic and tomographic study was made of the cranioencephalic topography of canary goats of medium weight and size. In a first step, the exocranialis references corresponding to an axis designed at the level of the meatus acusticus externus and parallel to the basicranial axis were anatomically and radiologically defined. Conventional stereotaxic techniques were then used to reach the standard position of the head in order to obtain macroscopical cross sections at different levels perpendicular to the base of the cranium. In a second step, a tomographic study was made to confirm the design of the axis.

Animals↗
PubMed1996

Reversible denaturation of myo-inositol monophosphatase. The stability of the metal-binding loop.

The unfolding of bovine brain myo-inositol monophosphatase by guanidine. HCl (Gdn. HCl) has been investigated. The recovery of circular dichroism, emission spectra, and catalytic activity after dilution of Gdn.HCl-treated samples indicate that the overall process is reversible. The steepness of the spectroscopic changes between 3 M and 5 M Gdn.HCl, and the lack of any discernible plateau suggest that unfolding of the protein is a cooperative process. The sensitized luminescence of bound Tb(III) was used as a probe of conformational changes of the metal-binding loop. Denaturation of the enzyme by Gdn.HCl does not abolish sensitized luminescence. A 50% decrease in sensitized luminescence was observed in 5 M Gdn.HCl. Under this set of experimental conditions, the protein binds terbium with an association constant of 1 x 10(6)M-1. It is suggested that a residual structure of denatured myo-inositol monophosphatase is responsible for the binding of terbium ions. The kinetics of unfolding and refolding as a function of Gdn.HCl concentration were monitored by protein fluorescence in a stopped-flow instrument. The monophosphatase unfolded in a single kinetic phase with rate constants in the range 80-65 s-1 at 25 degrees C. The refolding kinetics fit monoexponential functions with rate constants in the range 120-65 s-1 depending on the Gdn.HCl concentration. Substantial refolding of the protein occurs within the dead time of mixing.

Animals↗
PubMed1996

Identification and characterisation of two transcriptional repressor elements within the coding sequence of the Saccharomyces cerevisiae HXK2 gene.

A well-defined set of isogenic yeast strains has been constructed whereby each strain contains a different HXK2::lacZ gene fusion integrated at the URA3 locus. These HXK2::lacZ fusions differ in the amount of the HXK2 gene (encoding hexokinase 2 isoenzyme) that is fused to the lacZ reporter gene. Comparison of the beta-galactosidase activities of each strain during growth on glucose or ethanol revealed that some part of the coding region between +39 and +404 bp is involved in repressing gene expression in a carbon source dependent manner. A series of deletions of this HXK2 coding region were constructed and fused upstream of a minimal CYC1::lacZ promoter. beta-Galactosidase activities on glucose or ethanol growth yeast calls revealed that two different regulatory elements are present in this DNA region. Gel mobility shift analysis and in vitro DNase I footprinting have shown that proteins bind specifically to two downstream repressor sequences (DRS1 located from +140 to +163 and DRS2 located between +231 and +251) that influence the rate of HXK2 transcription when ethanol is used as carbon source by Saccharomyces cerevisiae. We identified and partially purified a 18 kDa protein that binds specifically to synthetic double-stranded oligonucleotides containing the (A/C)(A/G)GAAAT box sequence. Our data suggest that p18 synthesis is under the control of genes involved in glucose repression (MIG1 = CAT4) and glucose derepression (SNF1 = CAT1).

Base Sequence↗
PubMed1996

Glucose-induced inactivation of isocitrate lyase in Saccharomyces cerevisiae is mediated by the cAMP-dependent protein kinase catalytic subunits Tpk1 and Tpk2.

Glucose-induced inactivation of isocitrate lyase (Icl) has been related to protein phosphorylation. Moreover, since rapid reversible inactivation preceded irreversible inactivation of the enzyme, phosphorylation was proposed as the triggering reaction that makes the enzyme accessible to the proteolytic machinery. The protein kinase involved in the process is unknown at the moment. In this work we demonstrate that Tpk1 and Tpk2, the catalytic subunits of cAMP-dependent protein kinase, are involved in the signalling of short-term and long-term inactivation processes of Icl. We also demonstrate that threonine 53 is involved in a regulatory mechanism necessary for short-term reversible inactivation of Icl, probably mediated through its phosphorylation. Other, as yet unidentified, residues are likely to be the target of distinct protein kinases mediating the irreversible long-term inactivation of Icl.

Base Sequence↗
PubMed1996

Molecular analysis of the promoter region of the hexokinase 2 gene of Saccharomyces cerevisiae.

lacZ fusions of the hexokinase 2 gene promoter were constructed and a deletion analysis was performed in order to identify the cis-acting regulatory elements of the promoter that controls hexokinase 2 gene expression. Expression of the hexokinase 2 gene is induced by glucose and around 40-fold repressed by ethanol. This repression seems to be mediated mainly by a repression element located within the coding region of the hexokinase 2 gene, between +39 and +404 bp from the ATG start codon. A second repressing element for ethanol growing cells was located between -455 bp and -254 bp. A synergistic effect on repression of transcription, when ethanol is the carbon source used for growth, was demonstrated by experiments in which both repressing elements were simultaneously removed. The finding of regulatory sequences in the coding region of the hexokinase 2 gene stimulates a search for regulatory elements in the coding region of other yeast genes.

Cloning, Molecular↗
PubMed1996

Cross-reactivity between a penicillin and a cephalosporin with the same side chain.

BACKGROUND: The cross-reactivity between penicillins and cephalosporins can be influenced by different factors, which are not all well known. The chemical structure of the side chain may contribute to the cross-reactivity. OBJECTIVE: The study was carried out in allergic subjects who are selectively responsive to amoxicillin to determine allergenic cross-reactivity with a cephalosporin containing a side chain identical to that of amoxicillin, cefadroxil, and one containing a different side chain, cefamandole. METHODS: Allergic subjects with a selective response to amoxicillin were chosen according to the following criteria: history of an immediate allergic reaction to amoxicillin, negative skin test responses to benzylpenicilloyl and minor determinant mixture of benzylpenicillin, negative RAST response to benzylpenicilloyl, and good tolerance to benzylpenicillin and phenoxymethyl penicillin challenges. In addition, subjects had to have a positive skin test response to amoxicillin and/or positive RAST response to amoxicilloyl or, if these test results were negative, a positive challenge test response to amoxicillin. In vivo cross-reactivity to cefadroxil was assessed by giving oral cefadroxil at increasing doses from 5 to 500 mg. In vitro cross-reactivity was determined by RAST inhibition studies with amoxicilloyl RAST disks and the following monomeric conjugates in the fluid phase: amoxicillin-butylamine, cefadroxil-butylamine, and the side chain para-hydroxy-phenylglycine. Tolerance to cefamandole was determined by giving 100 mg and then 500 mg parenterally. RESULTS: Twenty-one patients with a selective response to amoxicillin were included in the study. Eight subjects (38%) had a positive response to cefadroxil, and none reacted to cefamandole. In vitro RAST inhibition studies indicated that cefadroxil-butylamine monomers cross-reacted with amoxicillin butylamine and the side chain contributed relevantly to the inhibition. CONCLUSIONS: These results indicate that the percentage of cross-reactivity between penicillins and cephalosporins with an identical side chain is high and that this critical part of the molecule seems to be an important contributor to these results. The value is higher than previously reported data from similar studies of non-side-chain-related cephalosporins.

Adolescent↗
PubMed1996

Controlled study on the improvement of quality of life in elderly hemodialysis patients after correcting end-stage renal disease-related anemia with erythropoietin.

Despite the long experience in erythropoietin (EPO) treatment in end-stage renal disease (ESRD)-related anemia, controversy remains as to whether EPO treatment of anemia can improve the quality of life (QL) in elderly ESRD patients, as it does in younger ones. We conducted a prospective study of 57 stable patients on hemodialysis who started on EPO treatment. A control group of 29 hemodialysis patients not requiring EPO was simultaneously studied. Diabetic patients and patients with severe comorbidity were excluded. Quality of life was assessed at baseline before EPO treatment and after 3 and 6 months of follow-up, using the Karnofsky scale (KS) and the Sickness Impact Profile (SIP) questionnaire. A high KS score and a low SIP score indicate better QL. Erythropoietin patients were stratified into two age groups: <60 years (n = 34) and > or = 60 years (n = 23). In the EPO group mean hematocrit values improved from 21 percent at baseline to 29 percent at the sixth month; mean KS scores increased from 68 +/- 1.8 to 81 +/- 1.5 (P < 0.0001) and the mean global score of SIP decreased from 19.8 +/- 1.6 to 13.5 +/- 1.2 (P < 0.0001). No significant changes were observed in the control group. Elderly patients in the EPO group showed improved KS scores, from 61 +/- 1.5 to 75 +/- 2.5 (P < 0.0001), and the global score of SIP decreased from 27.7 +/- 2.1 to 20 +/- 1.8 (P < 0.001). Younger patients had improvement of their KS scores, from 73 +/- 2.5 to 85 +/- 1.5 (P < 0.0001), and the global score of SIP decreased from 14.5 +/- 1.9 to 9.1 +/- 1.2 (P < 0.001). No relationship was found between age groups and improvement in QL indicator scores. On regression analysis, a poor basal QL score was related to higher QL improvement under EPO treatment, and final hematocrit was positively related to global SIP improvement. Treatment of ESRD-related anemia with EPO significantly improved the QL of hemodialysis patients. Quality of life in elderly patients improved as much as in younger patients, thereby fully justifying the use of EPO for the elderly.

Adolescent↗
PubMed1996

Molecular analysis of the SMN and NAIP genes in Spanish spinal muscular atrophy (SMA) families and correlation between number of copies of cBCD541 and SMA phenotype.

Spinal muscular atrophy is an autosomal recessive disorder which affects about 1 in 10,000 individuals. The three clinical forms of SMA were mapped to the 5q13 region. Three candidate genes have been isolated and shown to be deleted in SMA patients: the Survival Motor Neuron gene (SMN), the Neuronal Apoptosis Inhibitory Protein gene (NAIP) and the XS2G3 cDNA. In this report we present the molecular analysis of the SMN exons 7 and 8 and NAIP exon 5 in 65 Spanish SMA families. NAIP was mostly deleted in type I patients (67.9%) and SMN was deleted in 92.3% of patients with severe and milder forms. Most patients who lacked the NAIP gene also lacked the SMN gene, but we identified one type II patient deleted for NAIP exon 5 but not for SMN exons 7 and 8. Two other patients carried deletions of NAIP exon 5 and SMN exon 7 but retained the SMN exon 8. Three polymorphic variants from the SMN gene, showing changes on the sequence of the centromeric (cBCD541) and telomeric copies of the SMN gene, were found. In addition, we show several genetic rearrangements of the telomeric SMN gene, which include duplication of this gene in one normal chromosome, and putative gene conversion events in affected and normal chromosomes. Altogether these results corroborate the high genetic variability of the SMA region. Finally, we have determined the ratio between the number of centromeric and telomeric copies of the SMN gene in parents of SMA patients, showing that the majority of parents of types II and III patients carried three or more copies of the cBCD541 gene; we suggest a relationship between the number of copies of cBCD541 and the disease phenotype.

Base Sequence↗
PubMed1996

A novel locus for non-syndromic sensorineural deafness (DFN6) maps to chromosome Xp22.

Non-syndromic X-linked deafness is highly heterogeneous. At least five different clinical forms have been described, but only two loci have been mapped. Here we report a Spanish family affected by a previously undescribed X-linked form of hearing impairment. Deafness is non-syndromic, sensorineural, and progressive. In affected males, the auditory impairment is first detected at school age, affecting mainly the high frequencies. Later it evolves to become severe to profound, involving all frequencies for adulthood. Carrier females manifest a moderate hearing impairment in the high frequencies, with the onset delayed to the fourth decade of life. Deafness was assumed to be X-linked dominant, with incomplete penetrance and variable expressivity in carrier females. The family was genotyped for a set of microsatellite markers evenly spaced at intervals of about 10 cM. We found evidence of linkage to markers in the Xp22 region (maximum lod score of 5.30 at theta = 0.000 for DXS8036 and for DXS8022). The position of the novel deafness locus (DFN6) was refined by haplotype analysis. Mapping of the breakpoints in two critical recombinants allowed us to define an interval for DFN6, delimited by DXS7108 on the distal side and by DXS7105 on the proximal side, and spanning a genetic distance of about 15 cM.

Audiometry, Pure-Tone↗
PubMed1996

Quality of life in dialysis patients. A spanish multicentre study. Spanish Cooperative Renal Patients Quality of Life Study Group.

The aim of this study was to evaluate the quality of life in patients on chronic dialysis and to research the influence of various factors related to treatment and ESRD on quality of life. The cross-sectional study was carried out nationally and 1013 randomly selected stable patients on dialysis were evaluated. The evaluation of quality of life was by the Karnofsky Scale (KS) and the Sickness Impact Profile (SIP). Both questionnaires were self-reported. Co-morbidity was evaluated according to the Friedman Comorbidity Index. Adjusted quality of life scores for case-mix differences of several groups of patients were compared. Twenty-six per cent of the patients showed severe quality of life restriction on the Global Score of SIP (score > or = 20) and 31% on the KS (score < or = 60). The partial categories of the SIP that were more affected were work, recreation and pastimes, home management, and sleep and rest. No significant differences were found relating to dialysis technique, dialysis solution, or dialyser membrane. Greater haemoglobin concentrations were related to better quality of life scores on Physical Dimension and Global Score of SIP. Advanced age and Comorbidity Index were related to worse quality of life scores. We conclude that 25% of the patients showed an important effect of the disease on their quality of life. An increase in haemoglobin was related to better quality of life in dialysis patients. Advanced age and co-morbidity both adversely affected quality of life.

Adult↗
PubMed1996

Selective allergic reaction to oral cloxacillin.

BACKGROUND: Previous observations indicate that in some instances subjects allergic to penicillins may experience an allergic reaction after taking the drug by one route but have good tolerance after being administered the same drug by a different route. OBJECTIVE: The purpose was to establish if cloxacillin (CLX) induced a selective response only after oral route administration in a suspected case and to study if there were differences between the oral and parenteral formulations. METHODS: Skin tests were carried out using benzylpenicillin (BP) conjugated to poly-L-lysine (BPO-PLL), minor determinant mixture of benzylpenicillin (MDM), ampicillin (AMP), amoxicillin (AX) and cloxacillin (CLX). Radioallergosorbent assay (RAST) was carried out using BPO-PLL, AX-PLL and CLX-PLL sensitized discs. In the case the skin tests and RAST were negative, a controlled challenge administering the drug by both oral and parenteral route was made. Urine samples were taken at prechallenge (basal levels) and at three periods after challenge (1-3, 3-6 and 6-9 h). Analysis of oral and parenteral formulations was made by HPLC chromatography. RESULTS: All skin tests and RASTs were negative. With the challenge tests the patient tolerated parenteral BP and oral phenoxymethyl penicillin (PV) and oral and parenteral AMP up to therapeutic concentrations. Parenteral CLX (500 mg) was also tolerated but 30 min after administering 50 mg by the oral route progressive generalized erythema with pruritus, facial angioedema and tachycardia developed. Urine samples taken during the challenge tests showed an increased excretion of N-methyl histamine (N-MH) 3 h after challenge with oral CLX but no change in N-MH levels after challenge with parenteral CLX or the other penicillins, indicating that histamine was released during the allergic episode with oral CLX. HPLC analysis of the oral and parenteral CLX formulations indicated that there were no differences and that neither polymers no other contaminant materials were present. CONCLUSION: Although the nature of the allergenic determinant involved in the induction of the reaction is not yet known, the oral route may have favoured the production of a metabolite not generated by the parenteral route.

Administration, Oral↗