Search PubMed⌕ Search

Biomedical subjects

A Moya

Publications and source records attributed to A Moya.

At least 127 records · Page 7Linked to original sources
PubMed1989

Variability and evolution of the plant RNA virus pepper mild mottle virus.

The RNA genomes of 26 isolates of pepper mild mottle virus were compared by their RNase T1 fingerprints. Twenty-three isolates came from epidemic outbreaks in greenhouse-grown peppers in Almería (southeastern Spain) from 1983 to 1987; three other isolates, from 1980, came from Sicily (Italy) and Zaragoza (central Spain). The 26 fingerprints can be classified into 10 different types; nucleotide substitution rates show them to be very similar. Cluster and cladistic analyses group types corresponding to the Almería isolates separate from those of 1980. Intraannual and interannual nucleotide differences were estimated. An evolutionary model for pepper mild mottle virus built on these data indicates a highly stable population, maintaining its diversity through time, with a main prevailing haplotype from which closely related variants arise that do not replace it. This high stability could be due to strong functional constraints on variation, as suggested by the high proportion of invariant versus polymorphic sites in fingerprints.

Biological Evolution↗
PubMed1989

[Intravenous streptokinase in acute myocardial infarction. Reduction of early in-hospital mortality].

A randomized study of the effects of intravenous streptokinase was performed in 214 patients with an acute myocardial infarction of less than 4 hours of whom 110 were included in the therapeutic group (SK) and 104 in the control group (C). Incidence of angiographic recanalization was higher in SK group (71 vs 28%, p less than 0.001) as that of non-significant residual coronary artery stenosis (less than 70%, 16% vs 3%, p less than 0.005), particularly in young patients (less than 45 years; 42% vs 8%, p less than 0.05). However, SK group presented a higher incidence of severe residual stenosis (90-99%) (SK, 42% vs C, 22%, p less than 0.01). Ejection fraction was higher among recanalized patients in both groups. Peak CPK-MB occurred earlier in SK group (13 vs 19 hours, p less than 0.001) and also among the recanalized patients of each group (SK, 12 vs 16 hours, p less than 0.001; C, 15 vs 21 hours, 0.002). The course of ST segment was similar in the 2 groups. The occurrence of ventricular arrhythmias within the first hour was greater in SK group (40% vs 20%, p less than 0.002), whereas the incidence of pericarditis (14% vs 35%, p less than 0.001) and of early mortality (less than 5 days, 2% vs 10%, p less than 0.02) was lower in SK group. The incidence of cardiac rupture, confirmed at necropsy in each of the 5 cases studied, was also lower in SK group (1 vs 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Gene encoding capsid protein VP1 of foot-and-mouth disease virus: a quasispecies model of molecular evolution.

A phylogenetic tree relating the VP1 gene of 15 isolates of foot-and-mouth disease virus (FMDV) of serotypes A, C, and O has been constructed. The most parsimonious tree shows that FMDV subtypes and isolates within subtypes constitute sets of related, nonidentical genomes, in agreement with a quasispecies mode of evolution of this virus. The average number of nucleotide replacements per site for all possible pairs of VP1 coding segments is higher among representatives of serotype A than serotype C or O. In comparing amino acid sequences, the values of dispersion index (variance/mean value) are greater than 1, with the highest values scored when all sequences are considered. This indicates an accumulation of mutations at a limited number of residues, suggesting that distributions of sequences fluctuate around points of high stability. Evolution of FMDV follows a path very distant from that of a star phylogeny, and it has not been possible to derive conclusions on constancy of evolutionary rates with the test applied to the analysis. FMDVs, as other RNA viruses, are of limited genetic complexity and their population sizes are extremely large. Their evolution concerns complex, indeterminate mixtures of genomes rather than a single, determinate species.

Amino Acids↗
PubMed1988

Linkage disequilibrium in natural and experimental populations of Drosophila melanogaster.

We have studied linkage disequilibrium in Drosophila melanogaster in two samples from a wild population and in four large laboratory populations derived from the wild samples. We have assayed four polymorphic enzyme loci, fairly closely linked in the third chromosome: Sod Est-6, Pgm, and Odh. The assay method used allows us to identify the allele associations separately in each of the two homologous chromosomes from each male sampled. We have detected significant linkage disequilibrium between two loci in 16.7% of the cases in the wild samples and in 27.8% of the cases in the experimental populations, considerably more than would be expected by chance alone. We have also found three-locus disequilibria in more instances than would be expected by chance. Some disequilibria present in the wild samples disappear in the experimental populations derived from them, but new ones appear over the generations. The effective population sizes required to generate the observed disequilibria by randomness range from 40 to more than 60,000 individuals in the natural population, depending on which locus pair is considered, and from 100 to more than 60,000 in the experimental populations. These population sizes are unrealistic; the fact that different locus-pairs yield disparate estimates within the same population argues against the likelihood that the disequilibria may have arisen as a consequence of population bottlenecks. Migration, or population mixing, cannot be excluded as the process generating the disequilibria in the wild samples, but can in the experimental populations. We conclude that linkage disequilibrium in these populations is most likely due to natural selection acting on the allozymes, or on loci very tightly linked to them.

Alleles↗
PubMed1988

Mitochondrial DNA evolution in the Drosophila obscura group.

We report a restriction-site study of the mitochondrial DNA (mtDNA) of seven species of the Drosophila obscura group. One species (D. azteca) belongs to the affinis subgroup; the other six species are classified in the obscura subgroup, three of them being from the old-world species (D. obscura, D. ambigua, and D. subobscura) and three from the new-world species (D. pseudoobscura, D. persimilis, and D. miranda). The mtDNA patterns suggest that the phylogeny of the group needs to be revised. The Nearctic obscura species appear as more closely related to D. azteca (affinis subgroup) than to the Palearctic species. The three Palearctic species are, in turn, a very heterogeneous group, with D. obscura no more closely related to D. subobscura and D. ambigua than to D. affinis or the Nearctic obscura species. The rates of mtDNA evolution are variable: some lineages have evolved at rates two or three times greater than others. If an average rate of 0.5% nucleotide substitutions/Myr is assumed, the divergence among the four main lineages in the phylogeny would have occurred 12-15 Myr ago, during the Miocene, which is consistent with biogeographic information.

Animals↗
PubMed1988

Octapolar electrocatheter for His bundle recording and sequential bedside electrophysiologic testing.

To reduce the number of electrocatheters required for an electrophysiologic study and to facilitate prolonged monitoring of the electrical properties of the heart, an octapolar electrocatheter was designed and tested in 45 consecutive patients undergoing routine electrophysiologic studies. The electrocatheter introduced into the right ventricle served for: (a) right ventricular pacing; (b) recording of low lateral and low septal right atrial electrograms; (c) recording of the His bundle potential in 39 out of the 45 patients (86%); (d) 24-hour monitoring of the AV conduction intervals and refractory periods at the patients' bedsides. The octapolar electrocatheter reduced the number of probes required for studying the mechanisms of reciprocating tachycardia and allowed 24-hour bedside electrophysiologic monitoring.

Adult↗
PubMed1987

Daily variability of electrically induced reciprocating tachycardia in patients with atrioventricular accessory pathways.

Sequential bedside electrophysiologic testing was performed over 22 hours at intervals of 1 to 2 hours in 13 patients with left-sided Kent bundles to assess possible daily variations in the capacity to electrically induce reciprocating tachycardia. In all patients the tachycardia involved the accessory pathway in retrograde atrial activation. Between midnight and early morning the more relevant findings with respect to the first testing performed at midday were a significant prolongation of the effective refractory period of the atrial (from 212 +/- 22 msec to 229 +/- 22 msec; p less than 0.01), atrioventricular node (from 235 +/- 22 msec to 285 +/- 15 msec; p less than 0.005), right ventricle (from 209 +/- 15 msec to 221 +/- 12 msec; p less than 0.001), and retrograde Kent bundle (from 278 +/- 34 msec to 294 +/- 24 msec; p less than 0.01) and a reduction of the inducibility of tachycardia from both the coronary sinus from 90% to 50%; p less than 0.001) and the right ventricle from 80% to 15%; p less than 0.001). Thus our results indicate that there exists a nocturnal protection against electrical induction of reciprocating tachycardia that is associated with a prolongation of the atrial, atrioventricular nodal, ventricular, and Kent bundle refractoriness.

Adolescent↗
PubMed1986

Circadian variations in the electrical properties of the human heart assessed by sequential bedside electrophysiologic testing.

To assess the variability of the currently used electrophysiologic parameters and their possible circadian rhythm, sequential bedside electrophysiologic testing was performed during a 24-hour period, at intervals of 1 to 2 hours, in 12 patients who had normal atrioventricular (AV) conduction times and normal sinus node function. The coefficients of variation during the 24-hour period were: +/- 10.4% for the R-R interval, +/- 10.6% for the sinus node recovery time (SRT) at atrial pacing of 100 bpm, +/- 32.5% for the corrected SRT, +/- 15.1% for the ventriculoatrial (VA) effective refractory period (ERP), +/- 8.3% for the AV nodal ERP, +/- 5.7% for the AH interval, +/- 5.2% for the HV interval, +/- 5.5% for the atrial ERP, +/- 3.3% for the right ventricular ERP, +/- 2.8% for the QT interval, +/- 4% for the VA interval, and +/- 3.4% for the retrograde Kent bundle ERP. Between 12:00 midnight and 7:00 AM, there was significant lengthening of: the sinus node rate (p less than 0.0005), the SRT at atrial paced rates of 100 and 120 bpm (p less than 0.025), the QT interval duration (p less than 0.025), and the ERP of the atria (p less than 0.025), AV node (p less than 0.01), and right ventricle (p less than 0.05). Thus conventional electrophysiologic parameters are subject to daily variability and, like sinus node function, AV nodal and myocardial refractoriness follow a circadian rhythm with an acrophase between 12:00 midnight and 7:00 AM. In addition, prolonged bedside recording of the His bundle potential can be reliably obtained.

Adolescent↗
PubMed1986

Natural populations of Trypanosoma cruzi, the agent of Chagas disease, have a complex multiclonal structure.

We have studied 15 gene loci coding for enzymes in 121 Trypanosoma cruzi stocks from a wide geographic range--from the United States and Mexico to Chile and southern Brazil. T. cruzi is diploid but reproduction is basically clonal, with very little if any sexuality remaining at present. We have identified 43 different clones by their genetic composition; the same genetic clone is often found in very distant places and in diverse hosts. There is much genetic heterogeneity among the different clones, and they cannot be readily classified into a few discrete groups that might represent natural taxa. These findings imply that the biological and medical characteristics need to be ascertained separately for each natural clone. The evidence indicates that clonal evolution is very ancient in T. cruzi. We propose two alternative hypotheses concerning the relationship between the biochemical diversity and the heterogeneity in other biological and medical characteristics of T. cruzi. One hypothesis is that the degree of diversity between strains simply reflects the time elapsed since their last common ancestor. The second hypothesis is that biological and medical heterogeneity is recent and reflects adaptation to different transmission cycles. A decision between the two hypotheses can be reached with appropriate studies, with important medical consequences.

Alleles↗
PubMed1986

Evolution of mitochondrial DNA in Drosophila subobscura.

The colonization of the New World by the Palearctic species Drosophila subobscura was first detected in 1978 in South America and around 1982 in western North America. The ensuing dramatic expansion of the species, in territory as well as numbers, provides an opportunity for studying evolution in a scale rarely possible. We have used 10 restriction endonucleases to analyze the mitochondrial DNA (mtDNA) of individuals from 23 widely dispersed localities. Only two mtDNA composite morphs have been detected in the Americas. None of the two morphs has been found in Africa, and only one in the Atlantic islands; but both are widespread in Europe, which provides no clue of the precise geographic origin of the colonizers. The amount of nucleotide-substitution polymorphism detected in D. subobscura is typical for animals, but it is greater in the Old than in the New World, presumably due to the recent colonization by a limited number of colonizers. Assuming standard evolutionary rates of mtDNA base substitution, the mtDNA morphs found in D. subobscura can be traced to a single one that existed no less than one million years ago. We argue against the inference that the D. subobscura flies now living descend from only one or a few females that lived at that time. This type of inference, which we call the "Mother Eve hypothesis," has been made to conclude that the human population went through a severe constriction about 200,000 years ago, so that all living humans descend from only one or a few women who lived at that time. The Mother Eve hypothesis is fallacious.

Journal Article↗
PubMed1986

Irradiation-resistance conferred by superoxide dismutase: possible adaptive role of a natural polymorphism in Drosophila melanogaster.

The toxic effects of ionizing radiation to DNA are thought to be due to the generation of the superoxide radical, 02-. Superoxide dismutase (SOD), which scavenges 02-., has been invoked as a protecting enzyme against ionizing radiation in viruses, bacteria, mammalian cells in culture, and live mice. We now demonstrate that SOD is involved in the resistance of Drosophila melanogaster against irradiation. The protection is greatest when flies carry the S form of the enzyme (which exhibits highest in vitro specific activity), intermediate when they carry the F form of the enzyme, and lowest when they are homozygous for N, an allele that reduces the amount of the enzyme to 3.5% of the normal level. Natural selection experiments show that the fitness of the high-activity S allele is increased in an irradiated population relative to the nonirradiated control. These results point towards a possible adaptive function of the S/F polymorphism found in natural populations of D. melanogaster.

Adaptation, Physiological↗
PubMed1986

Resting angina with fixed coronary artery stenosis: nocturnal decline in ischemic threshold.

Atrial pacing was performed in 16 patients with angina at rest and significant coronary artery stenosis (greater than 70%) over 2 consecutive days in the morning (10 A.M. to 1 P.M.), in the afternoon (4 to 7 P.M.), and at night (12 midnight to 3 A.M.) to assess possible circadian variations of their ischemic threshold. Overall, the incidence of resting angina was highest at night. All pacing results were positive (greater than or equal to 1.0 mm ST segment shift) and tended to be reproducible in nine patients, whereas some or all were negative in seven. Among all positive results, ischemic thresholds at night were significantly lower than those in the morning and in the afternoon (125 +/- 3 vs 138 +/- 3 and 139 +/- 2 beats/min, mean +/- SEM; p less than .005). In nine patients, 19 pacing tests produced ST segment elevation, of which 13 were performed at night (68%). We conclude that patients with resting angina and severe coronary stenosis often exhibit a nocturnal decline in their ischemic threshold, which seems to facilitate development of transmural ischemia during atrial pacing.

Angina Pectoris↗
PubMed1985

Pharmacokinetics of intravenous propafenone in patients with episodes of paroxysmal supraventricular tachycardia.

The plasma concentration time curves of propafenone after administration of single i.v. (2.3 +/- 0.2 mg/kg) doses have been studied in ten patients undergoing an electrophysiological study to evaluate episodes of recurrent supraventricular tachycardia. The propafenone kinetics profile can be described by a two-compartment open model. Mean values of main variables were t 1/2 alpha = 2.8 min, t 1/2 beta = 80 min, Kel = 0.12 min, -1, Vd beta = 1.6 1/kg, Cl = 1.03 1/h and AUR = 3.1 mg/h-1.

Adult↗
PubMed1981

Pericentric inversions of chromosome 12 in two families.

Two cases of pericentric inversion of chromosome 12 are presented, one 46,XX,inv(12)(p13;q11) and the other was also a heterozygotic carrier of the inversion. These inversions were detected among 4035 cytogenetic analyses carried out in patients with psychosomatic retardation and/or malformations (357 with a Down phenotype) and in patients with histories of miscarriages, sterility, or growth failure. In cases studied from a review of the literature together with our own we found that among 3235 cases of Down syndrome there were 7 patients with trisomy 21 and inherited balanced reciprocal translocation involving chromosomes other than pair 21. The frequent participation of some chromosomes in these balanced reciprocal translocations, above all those of group A (1-3), suggests that these and probably other rearrangements could make the segregation of chromosome 21 easier.

Child↗
PubMedDate not supplied

[Assessment of home parenteral nutrition programme in terminal oncological patients].

BACKGROUND AND GOALS: The assessment of the acceptance of the diets served at the hospital allows the introduction of adjustments to improve the quality of the service provided to hospitalized patients by preventing the complications derived from incorrect nutrition and enhancing their stay in hospital. The goal of the present study was to analyze the acceptance of the menus offered by the Hospital's catering service. SCOPE OF THE STUDY: Menus provided by the catering service of the "Sant Joan de Reus" University Hospital. MATERIAL AND METHODS: A total of 160 tray meals consumed were assessed, all chosen at random and corresponding to standard diets and special diets, including puréed food. The assessment was made by two dieticians in the hospital's kitchens. A visual scale was used with the following scores: 0 for a full plate, 1 for residual food amounting to over 75%, 2 from 50% to 75%, 3 more than or equal to 25% and 4 for empty plates. RESULTS: A total of 68 trays containing a standard diet were analyzed, together with 34 containing special diets and 41 with puréed food. The remains on 36 different courses from the standard diet were analyzed. The mean acceptance score was 3.01 +/- 1.30 in the case of the first courses, 3.24 +/- 1.11 in second courses and 3.53 +/- 0.96 for the desserts. As for special diets, a total of 27 different courses were analyzed. The mean acceptance score was 2.87 +/- 1.38 in the case of the first courses, 3.02 +/- 1.27 in second courses and 3.49 +/- 1.22 for the desserts. The first courses of puréed diets received the worst score of all the dishes served, although the overall mean score was good, 2.76 +/- 1.5. CONCLUSIONS: In general, a good level of acceptance has been observed for the set meals served in the hospital. Knowing which courses have lower acceptance scores allows changes to be proposed to the hospital menus, with their replacement by others with foreseeably better acceptance.

Adult↗
PubMedDate not supplied

[Approximation to the epidemiology of salt intake and arterial pressure. Study on a community of Toledo].

The relationship between salt intake and Blood Pressure (BP) is studied in a random sample of adults from 25 to 64 years of age in a urban community in Toledo, by means of a semiquantitative determination with a reactive (Saltex strip). Of the 3,824 people included in the census (1984), 384 were selected, regarding whom, in addition to the Cl- NaCl in the night fraction of urine being studied, the average BP of two samples, the body mass index (BMI), chronic communicable diseases, the use of tobacco, alcohol and drugs, as well as other social variables of the population were studied. Data was collected regarding the salt intake of 238 individuals and the BP of 236 individuals. A prevalence of high blood pressure (BP greater than 140 and/or 90 mmHg) in 14% was observed, and 81% of the sample studied ingested over 11 g of salt daily. The results were analyzed in strata, by age and BMI to avoid factors resulting in confusion, no relationship between salt intake, BP and rest of the variables studied being found in our community.

Adult↗