RÉSUMÉ
INTRODUCTION: There is a lack of data about adverse events (AE) in intermediate and long-term care centers (ILCC). We aimed to synthesize the available scientific evidence on instruments used to identify and characterize AEs. We also aimed to describe the most common adverse events in ILCCs. MATERIAL AND METHODS: A narrative systematic review of the literature was conducted according to Prisma recommendations. The PubMed database was searched for articles published between 2000 and 2021. Two reviewers independently screened and reviewed the studies through blind and independent review. We evaluated bias risk with Cochrane's risk of bias tool. Disagreements were resolved by consensus. Discrepancies that were not resolved by discussion were discussed with a third reviewer. Descriptive data was extracted and qualitative content analysis was performed. RESULTS: We found 2191 articles. Based on the inclusion and exclusion criteria, 272 papers were screened by title and abstract, and 66 studies were selected for full review. The instruments used to identify AEs were mostly tools to identify specific AEs or risks of AEs (94%), the remaining 6% were multidimensional. The most frequent categories detected medication-related AEs (n=26, 40%); falls (n=7, 11%); psychiatric AEs (6.9%); malnutrition (4.6%), and infections (4.6%). The studies that used multidimensional tools refer to frailty, dependency, or lack of energy as predictors of AEs. However, they do not take into account the importance of detecting AEs. We found 2-11 adverse drug events (ADE) per resident/month. We found a prevalence of falls (12.5%), delirium (9.6-89%), pain (68%), malnutrition (2-83%), and pressure ulcers (3-30%). Urinary tract infections, lower respiratory tract infections, skin and soft tissue infections, and gastroenteritis were the most common infections in this setting. Transitions between different care settings (from hospitals to ILCC and vice versa) expose AE risk. CONCLUSION: There are many instruments to detect AEs in ILCC, and most have a specific approach. Adverse events affect a significant proportion of patients in ILCC, the nurse-sensitive outcomes, nosocomial infections, and adverse drug events are among the most common. The systematic review was registered with Prospero, ID: CRD42022348168.
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OBJECTIVES: To support patients with limited health literacy with the challenges they face in the day-to-day management of their disease(s), numerous self-management interventions (SMIs) have been developed. To date, it is unclear to what extent SMIs have been developed for chronically ill patients with limited health literacy. This study aims to provide a description of these SMIs and to provide insight in their methodological components. METHODS: A secondary analysis of the COMPAR-EU database, consisting of SMIs addressing patients with diabetes, chronic obstructive pulmonary disease, obesity and heart failure, was conducted. The database was searched for SMIs addressing health literacy, including cognitive aspects and the capacity to act. RESULTS: Of the 1681 SMIs in the COMPAR-EU database, 35 studies addressed health literacy, describing 39 SMIs. The overview yields a high variety in interventions given, with overlapping information, but also lacking of specific details. DISCUSSION: This descriptive analysis shows that there was a large variety in the extensiveness of the description of intervention characteristics and their justification or explanation. A focus on the broad concept of health literacy, including functional skills, cognitive skills and the capacity to act could improve the effectiveness. This should be taken into account in the future development of SMIs.
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Fruits serve as a source of energy, vitamins, minerals, and dietary fiber. One of the barriers in increasing fruit and vegetables consumption is time required to prepare them. Overall, fruit bars have a far greater nutritional value than the fresh fruits because all nutrients are concentrated and, therefore, would be a convenience food assortment to benefit from the health benefits of fruits. The consumers prefer fruit bars that are more tasted followed by proper textural features that could be obtained by establishing the equilibrium of ingredients, the proper choosing of manufacturing stages and the control of the product final moisture content. Fruit bar preparations may include a mixture of pulps, fresh or dried fruit, sugar, binders, and a variety of minor ingredients. Additionally to the conventional steps of manufacturing (pulping, homogenizing, heating, concentrating, and drying) there have been proposed the use of gelled fruit matrices, dried gels or sponges, and extruders as new trends for processing fruit bars. Different single-type dehydration or combined methods include, in order of increasing process time, air-infrared, vacuum and vacuum-microwave drying convective-solar drying, convective drying, and freeze drying are also suggested as alternative to solar traditional drying stage. The dehydration methods that use vacuum exhibited not only higher retention of antioxidants but also better color, texture, and rehydration capacity. Antioxidant activity resulting from the presence of phenolic compounds in the bars is well established. Besides this, fruit bars are also important sources of carbohydrates and minerals. Given the wide range of bioactive factors in fresh fruits that are preserved in fruit bars, it is plausible that their uptake consumption have a positive effect in reducing the risk of many diseases.
Sujet(s)
Technologie alimentaire/méthodes , Technologie alimentaire/tendances , Fruit , Antioxydants/analyse , Comportement du consommateur , Dessiccation/méthodes , Fruit/composition chimique , Gels , Humains , Valeur nutritive , Phénols/analyse , Extraits de plantes , Sensation , Casse-crouteRÉSUMÉ
OBJECTIVE: To assess the efficiency of pharmacological antiemetic prophylaxis in patients subjected to surgery under general anaesthetic in different postoperative nausea and vomiting (NVPO) risk groups. MATERIAL AND METHODS: A randomised, observational, prospective and multicentre cohort study was conducted. The study included 1239 patients from 26 hospitals who were subjected to elective surgery under general anaesthesia. The data collected included, demographic characteristics, the NVPO risk factors, anaesthetic technique, type of surgery, the duration, fluid therapy, antiemetic prophylaxis administered, and the incidence of NVPO in the first 24h after surgery. A stratified analysis (low, moderate and high risk) was performed with the intention of evaluating the relationship between prophylaxis and NVPO using a logistic regression model adjusted for propensity score. The number of patients needed to treat (NNT) to prevent an NVPO episode was then calculated for each of the strata. RESULTS: The incidence of NVPO in the low risk stratum was 21.6% without prophylaxis and 8.6% with prophylaxis, 31.3% compared to 17.7% in the moderate risk, and 46.5% compared to 32.7% in the high risk group. There was a significant protective effect in the three strata (odds ratio between treated and untreated patients) and in the NNT (95% CI) was 7 (5-11) in the low risk stratum, 7 (5-13) in that of the moderate risk, and 6 (4-16) in the high risk. CONCLUSIONS: The efficiency of pharmacological antiemetic prophylaxis in patients subjected to surgery under general anaesthesia was similar in all risk groups. Not providing antiemetic prophylaxis in low risk patients may not be justified due to the cost-effectiveness criteria. Future clinical guidelines to improve the quality of health care of patients operated on under general anaesthesia should consider the advantages of a universal NVPO prophylaxis.
Sujet(s)
Anesthésie générale , Antiémétiques/usage thérapeutique , Vomissements et nausées postopératoires/prévention et contrôle , Études de cohortes , Femelle , Humains , Incidence , Mâle , Adulte d'âge moyen , Vomissements et nausées postopératoires/épidémiologie , Études prospectives , Facteurs de risqueRÉSUMÉ
Objetivo. Valorar la eficiencia de la profilaxis antiemética farmacológica en pacientes sometidos a una intervención quirúrgica, bajo anestesia general, en diferentes grupos de riesgo de náuseas y vomitos postoperatorios (NVPO). Material y métodos. Se diseñó un estudio multicéntrico aleatorio prospectivo observacional de cohortes. Se estudiaron 1.239 pacientes procedentes de 26 hospitales sometidos a cirugía programada con anestesia general. Fueron registradas las características poblacionales, los factores de riesgo de NVPO, la técnica anestésica, el tipo de cirugía, la duración, la fluidoterapia, la profilaxis antiemética administrada y la incidencia de NVPO en las primeras 24h. Se realizó un análisis estratificado (riesgo bajo, moderado y alto) encaminado a evaluar la asociación entre profilaxis y NVPO mediante un modelo de regresión logística ajustado por propensity score. Posteriormente, se calculó en cada uno de los estratos el número de pacientes que es necesario tratar (NNT), para evitar un episodio de NVPO. Resultados. La incidencia de NVPO en el estrato de bajo riesgo fue del 21,6% sin profilaxis y del 8,6% con profilaxis, en el de riesgo moderado fue del 31,3% frente al 17,7% y en el de alto riesgo del 46,5% frente al 32,7%. Hubo un efecto protector de la profilaxis de forma significativa en los 3 estratos (odds ratio entre pacientes tratados y no tratados) y el NNT (IC del 95%) fue de 7 (5-11) en el estrato de bajo riesgo, 7 (5-13) en el de riesgo moderado y 6 (4-16) en el de riesgo elevado. Conclusiones. La eficiencia de la profilaxis antiemética farmacológica en pacientes sometidos a cirugía con anestesia general fue similar en todos los grupos de riesgo. La privación de profilaxis antiemética en los pacientes de bajo riesgo puede no estar justificada por criterios de coste-efectividad. Las futuras guías clínicas para la mejora de la calidad asistencial, de los pacientes intervenidos con anestesia general deberán considerar la conveniencia de una profilaxis universal de las NVPO(AU)
Objective. To assess the efficiency of pharmacological antiemetic prophylaxis in patients subjected to surgery under general anaesthetic in different postoperative nausea and vomiting (NVPO) risk groups. Material and methods. A randomised, observational, prospective and multicentre cohort study was conducted. The study included 1239 patients from 26 hospitals who were subjected to elective surgery under general anaesthesia. The data collected included, demographic characteristics, the NVPO risk factors, anaesthetic technique, type of surgery, the duration, fluid therapy, antiemetic prophylaxis administered, and the incidence of NVPO in the first 24h after surgery. A stratified analysis (low, moderate and high risk) was performed with the intention of evaluating the relationship between prophylaxis and NVPO using a logistic regression model adjusted for propensity score. The number of patients needed to treat (NNT) to prevent an NVPO episode was then calculated for each of the strata. Results. The incidence of NVPO in the low risk stratum was 21.6% without prophylaxis and 8.6% with prophylaxis, 31.3% compared to 17.7% in the moderate risk, and 46.5% compared to 32.7% in the high risk group. There was a significant protective effect in the three strata (odds ratio between treated and untreated patients) and in the NNT (95% CI) was 7 (5-11) in the low risk stratum, 7 (5-13) in that of the moderate risk, and 6 (4-16) in the high risk. Conclusions. The efficiency of pharmacological antiemetic prophylaxis in patients subjected to surgery under general anaesthesia was similar in all risk groups. Not providing antiemetic prophylaxis in low risk patients may not be justified due to the cost-effectiveness criteria. Future clinical guidelines to improve the quality of health care of patients operated on under general anaesthesia should consider the advantages of a universal NVPO prophylaxis(AU)
Sujet(s)
Humains , Mâle , Femelle , Groupes à Risque , Antiémétiques/usage thérapeutique , Anesthésie générale/méthodes , Anesthésie générale , Vomissements et nausées postopératoires/complications , Vomissements et nausées postopératoires/thérapie , Facteurs de risque , Antibioprophylaxie/méthodes , Résultat thérapeutique , Évaluation de l'Efficacité-Efficience des Interventions , Antiémétiques/métabolisme , Antiémétiques/pharmacologie , Études prospectives , Traitement par apport liquidien/méthodes , Traitement par apport liquidien , Odds ratioRÉSUMÉ
BACKGROUND: Major adverse cardiac and cerebrovascular events (MACCE) represent the most common cause of serious perioperative morbidity and mortality. Our aim was to identify risk factors for MACCE in a broad surgical population with intermediate-to-high surgery-specific risk and to build and validate a model to predict the risk of MACCE. METHODS: A prospective, multicentre study of patients undergoing surgical procedures under general or regional anaesthesia in 23 hospitals. The main outcome was the occurrence of at least one perioperative MACCE, defined as any of the following complications from admittance to discharge: cardiac death, cerebrovascular death, non-fatal cardiac arrest, acute myocardial infarction, congestive heart failure, new cardiac arrhythmia, angina, or stroke. The MACCE predictive index was based on ß-coefficients and validated in an external data set. RESULTS: Of 3387 patients recruited, 146 (4.3%) developed at least one MACCE. The regression model identified seven independent risk factors for MACCE: history of coronary artery disease, history of chronic congestive heart failure, chronic kidney disease, history of cerebrovascular disease, preoperative abnormal ECG, intraoperative hypotension, and blood transfusion. The area under the receiver-operating characteristic curve was 75.9% (95% confidence interval, 71.2-80.6%). CONCLUSIONS: The risk score based on seven objective and easily assessed factors can accurately predict MACCE occurrence after non-cardiac surgery in a population at intermediate-to-high surgery-specific risk.
Sujet(s)
Angiopathies intracrâniennes/étiologie , Cardiopathies/étiologie , Complications postopératoires/étiologie , Sujet âgé , Sujet âgé de 80 ans ou plus , Angiopathies intracrâniennes/épidémiologie , Études de cohortes , Électrocardiographie , Transfusion d'érythrocytes/effets indésirables , Femelle , Cardiopathies/épidémiologie , Humains , Incidence , Mâle , Adulte d'âge moyen , Période périopératoire , Complications postopératoires/épidémiologie , Études prospectives , Facteurs de risqueRÉSUMÉ
El cáncer colorrectal asociado al embarazo es una patología extremadamente infrecuente. Se presenta el caso de una paciente de 38 años con antecedentes familiares de cáncer de colon, cursando un embarazo de 35 semanas en la que se diagnosticó un cáncer de colon derecho. Se efectúa una revisión de la literatura en relación al diagnóstico y manejo de esta rara entidad.
Colorectal carcinoma during pregnancy is a rare event. We report a case of a 38-year-old woman with family history of colorectal cancer with a right colon cancer diagnosed at 35 weeks of gestation. The problem of diagnosis as well as management of colon cancer during pregnancy is discussed.
Sujet(s)
Humains , Adulte , Femelle , Grossesse , Adénocarcinome/chirurgie , Adénocarcinome/diagnostic , Complications tumorales de la grossesse/chirurgie , Complications tumorales de la grossesse/diagnostic , Tumeurs du côlon/chirurgie , Tumeurs du côlon/diagnostic , Troisième trimestre de grossesse , Résultat thérapeutiqueRÉSUMÉ
A duplex primer set for the amplification of mitochondrial DNA HVI and HVII control regions was evaluated for the optimization of a DNA sequencing protocol suitable for forensic casework. HVI and HVII products, with the absence of non-specific products, could be detected by agarose gel electrophoresis when as little as 0.5 and 0.1pg of DNA were amplified for 34 and 38 cycles, respectively. Because HVI and HVII amplicons are co-synthesized in the duplex PCR, fewer steps are required (lessening the risk of cross contamination events) and more frugal use of precious extracted DNA samples is possible, both desirable features for forensic casework. The ABI Prism BigDyetrade mark version 1.1 chemistry provided high quality sequencing data, with little or no background noise and uniform peak heights, outcomes that favored reliable detection of heteroplasmy, particularly at early sequence reads (<40 bases). Optimal compromise between sensitivity and sequence accuracy in the absence of noise was achieved starting at 150 mitochondrial genome copies. The protocol is effective (no sequence errors) with highly degraded DNA (average detectable template size of 200bp). Dual artificial template mixtures with the minor component at 15% suggests that heteroplasmy should be detected at this level with confidence.
Sujet(s)
Régions déterminant la complémentarité/génétique , Profilage d'ADN/méthodes , ADN mitochondrial/analyse , Analyse de séquence d'ADN/méthodes , Amorces ADN , Électrophorèse capillaire , Humains , Réaction de polymérisation en chaîne , Sensibilité et spécificitéRÉSUMÉ
Reported strains of Piscirickettsia salmonis, a pathogen of salmonid fishes, were analyzed by amplifying part of the internal transcribed spacer (ITS) of the ribosomal RNA (rRNA) operon followed by denaturing gradient gel electrophoresis (DGGE) of the amplicons. All amplified fragments differing in sequence were distinguished by migration during DGGE. A simpler format, constant denaturant gel electrophoresis (CDGE), allowed the same diagnostic distinctions among strains. Sampling during 1997 and 1998 of salmonids from 5 different sites on and near Chiloé Island in southern Chile displaying piscirickettsiosis revealed only P. salmonis resembling LF-89, the type strain first isolated in 1989. These observations are encouraging for control strategies, which might otherwise be compromised by unpredictable shifts of P. salmonis types in salmon farms. A competitive PCR assay offered insight about the power of PCR for quantification and about specific tissue invasiveness by this intracellular pathogen. This approach revealed that the PCR could amplify approximately 1 to 10 P. salmonis genome equivalents against a background of > 99.9% salmonid DNA. It also raised the possibility that the salmonid brain is an important site for P. salmonis survival, with its bacterial load in 1 individual having been about 100 times the loads observed in liver and kidney. Pathogen detection by competitive PCR in a surface seawater sample from a netpen in use indicated a density of about 3000 to 4000 P. salmonis cells (or their DNA remnants) 1(-1). Such quantitative estimates should aid decisions about disease prevention and management as, for example, choice of netpen sites following fallow periods and certification of ova, which are known conduits of infection.
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Infections bactériennes/médecine vétérinaire , ADN bactérien/composition chimique , Maladies des poissons/microbiologie , Gammaproteobacteria/génétique , Variation génétique , Salmonidae , Animaux , Aquaculture , Infections bactériennes/microbiologie , Séquence nucléotidique , Chili , ADN bactérien/isolement et purification , Données de séquences moléculaires , Oncorhynchus kisutch , Oncorhynchus mykiss , Réaction de polymérisation en chaîne/médecine vétérinaire , Polymorphisme génétique , ARN bactérien/génétique , ARN ribosomique/génétique , Analyse de séquence d'ADNRÉSUMÉ
Anopheles pseudopunctipennis, one of the primary vectors of malaria in the southwest of Colombia, was evaluated for susceptibility to the 3 major insecticide groups (organophosphates, pyrethroids, and carbamates) by bioassay and biochemical assay. Larval populations, which were collected principally from irrigation channels in agricultural areas, where the intensity of insecticide use varied, were utilized to establish susceptibility for the 1st time in this species. The baselines for each population showed a range of biological susceptibility to the insecticides evaluated, but overall no resistance was detected according to standards established by the World Health Organization. The high sensitivity of biochemical microassays enabled the detection of a small proportion of mosquitoes with higher levels of nonspecific esterases and mixed-function oxidases from 2 areas where agricultural application of organophosphate and pyrethroid insecticides had been heavy. These differences were not sufficient to affect susceptibility as measured by bioassay. No evidence of insensitive acetylcholinesterase was observed. Absence of resistance in areas that have experienced heavy insecticide application could be explained by genetic drift, by gene flow from areas without insecticide pressure, by manner of exposure to the insecticides, or by recent changes in agricultural activities that decreased insecticide use. Baseline values were established that serve as provisional susceptibility thresholds for applying simple Centers for Disease Control and Prevention biochemical assay and bioassay methods to larvae of this anopheline species.
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Anopheles , Insecticides , Lutte contre les moustiques , Acetylcholinesterase/analyse , Animaux , Anopheles/enzymologie , Dosage biologique , Colombie , Esterases/analyse , Malathion , Lutte contre les moustiques/méthodes , Oxidoreductases/analyse , Perméthrine , Propoxur , PyréthrinesRÉSUMÉ
The mitochondrial DNA (mtDNA) control region and flanking tRNAs were sequenced from 76 mice collected at 60 localities extending from Egypt through Turkey, Yemen, Iran, Afghanistan, Pakistan, and Nepal to eastern Asia. Segments of the Y chromosome and of a processed p53 pseudogene (Psip53) were amplified from many of these mice and from others collected elsewhere in Eurasia and North Africa. The 251 mtDNA types, including 54 new ones reported here, now identified from commensal house mice (Mus musculus group) by sequencing this segment can be organized into four major lineages-domesticus, musculus, castaneus, and a new lineage found in Yemen. Evolutionary tree analysis suggested the domesticus mtDNAs as the sister group to the other three commensal mtDNA lineages and the Yemeni mtDNAs as the next oldest lineage. Using this tree and the phylogeographic approach, we derived a new model for the origin and radiation of commensal house mice whose main features are an origin in west-central Asia (within the present-day range of M. domesticus) and the sequential spreading of mice first to the southern Arabian Peninsula, thence eastward and northward into south-central Asia, and later from south-central Asia to north-central Asia (and thence into most of northern Eurasia) and to southeastern Asia. Y chromosomes with and without an 18-bp deletion in the Zfy-2 gene were detected among mice from Iran and Afghanistan, while only undeleted Ys were found in Turkey, Yemen, Pakistan, and Nepal. Polymorphism for the presence of a Psip53 was observed in Georgia, Iran, Turkmenistan, Afghanistan, and Pakistan. Sequencing of a 128-bp Psip53 segment from 79 commensal mice revealed 12 variable sites and implicated >/=14 alleles. The allele that appeared to be phylogenetically ancestral was widespread, and the greatest diversity was observed in Turkey, Afghanistan, Pakistan, and Nepal. Two mice provided evidence for a second Psip53 locus in some commensal populations.
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ADN mitochondrial/génétique , Variation génétique/génétique , Souris/génétique , Phylogenèse , Animaux , Séquence nucléotidique , Protéines de liaison à l'ADN/génétique , Gènes p53/génétique , Mâle , Moyen Orient , Données de séquences moléculaires , Musées , Réaction de polymérisation en chaîne/méthodes , Pseudogènes/génétique , ARN de transfert/génétique , Analyse de séquence d'ADN , Délétion de séquence , Peau , Séquences répétées en tandem , Facteurs de transcription , Chromosome Y/génétiqueRÉSUMÉ
The attributes of the PCR allowed implementation of an assay for specific detection of Piscirickettsia salmonis from a few microliters of fish serum. This opens the way to less invasive modes of sampling for this microbial pathogen in salmonids.
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Maladies des poissons/diagnostic , Bactéries à Gram négatif/isolement et purification , Infections bactériennes à Gram négatif/médecine vétérinaire , Réaction de polymérisation en chaîne/méthodes , Salmonidae/microbiologie , Animaux , Aquaculture , Bactériémie/diagnostic , Bactériémie/médecine vétérinaire , ADN bactérien/analyse , ADN bactérien/isolement et purification , ADN ribosomique/analyse , ADN ribosomique/isolement et purification , Bactéries à Gram négatif/génétique , Infections bactériennes à Gram négatif/diagnostic , Infections bactériennes à Gram négatif/microbiologie , Muscles/microbiologie , Opéron/génétique , ARN ribosomique 23S/génétiqueRÉSUMÉ
The phylogenetic compositions of bacterioplankton assemblages from San Francisco Bay and Tomales Bay, Calif., differed substantially when analyzed by PCR-denaturing gradient gel electrophoresis; these differences are consistent with the results of previous studies demonstrating differences in their metabolic capabilities. PCR-denaturing gradient gel electrophoresis analysis of complex microbial assemblages was sensitive and reliable, and the results were reproducible as shown by experiments with constructed and naturally occurring assemblages.
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Bactéries/génétique , Plancton/génétique , Plancton/microbiologie , Animaux , Bactéries/classification , Bactéries/isolement et purification , Séquence nucléotidique , Californie , Amorces ADN/génétique , ADN bactérien/génétique , ADN bactérien/isolement et purification , ADN ribosomique/génétique , ADN ribosomique/isolement et purification , Électrophorèse sur gel de polyacrylamide , Données de séquences moléculaires , Phylogenèse , Plancton/classification , Réaction de polymérisation en chaîneRÉSUMÉ
Oligonucleotide primers directed to the minicircle kinetoplast DNA of Leishmania strains supported enzymatic amplification of this DNA by the polymerase chain reaction (PCR). A single product of 70 basepairs was obtained from parasites belonging exclusively to the L. braziliensis complex. Direct sequencing of the amplified product confirmed its minicircle origin. Skin biopsy specimens from human patients were used directly for the PCR. A pulse incubation of such specimens with deoxyribonuclease I prior to the PCR increased the reliability of the assay. Nuclease disruption of the kinetoplast network was expected to make more copies of the minicircle accessible to amplification. Comparative results between the PCR and conventional parasitologic detection procedures indicate that the DNA detection approach presented is by far more sensitive for diagnostic purposes. Innovations in the PCR protocol are presented that adapt the diagnosis of leishmaniasis to settings with minimal equipment and that are distant from central laboratories.
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ADN circulaire/analyse , Leishmania brasiliensis/génétique , Leishmaniose cutanée/diagnostic , Leishmaniose cutanéomuqueuse/diagnostic , Réaction de polymérisation en chaîne , Animaux , Séquence nucléotidique , ADN kinétoplastique , ADN des protozoaires/analyse , Études d'évaluation comme sujet , Humains , Données de séquences moléculaires , Oligodésoxyribonucléotides/composition chimique , Sensibilité et spécificité , Peau/parasitologieRÉSUMÉ
Protein extracts originally prepared for isozyme electrophoresis two decades ago contain surviving DNA sequences susceptible to amplification by the polymerase chain reaction (PCR). Amplification was also possible after stabilization of such extracts on filter paper and immersion under mineral oil without refrigeration.
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ADN/génétique , ADN/isolement et purification , Musées , Réaction de polymérisation en chaîne/méthodes , Animaux , Séquence nucléotidique , Cytochromes de type b/génétique , Amorces ADN/génétique , Stabilité de médicament , Écosystème , Enzymes/génétique , Enzymes/isolement et purification , Amplification de gène , Huile minérale , Données de séquences moléculaires , Facteurs temps , Urodela/génétiqueRÉSUMÉ
Strains of Salmonella typhimurium deficient in topoisomerase I activity (topA mutants) are UV sensitive and non-mutable (Overbye and Margolin: J Bacteriol 146:170-178, 1981). Using lac-operon fusions to DNA damage inducible (din) loci we investigated whether these observations could be explained by an inability of topA strains to efficiently induce DNA damage responses. Mitomycin C (MMC)-induced expression of lac-operon fusions to uvrB and to a second SOS locus, din-9, was largely eliminated in topA bacteria. The inducible expression of several other din-fusions was also diminished. This inducibility defect was mimicked by growth of din-9 topA+ bacteria in media of high osmolarity, a condition that leads to increased DNA supercoiling. Inhibitors of DNA gyrase efficiently induced din-9 in topA bacteria. Together, these results suggest that the topA effect on din expression may be mediated at the level of DNA supercoiling. The sensitivities of a number of din-fusions to topA paralleled the degree to which they were repressed by excess LexA, suggesting that mutations in topA might influence LexA-operator interactions and/or increase lexA expression.
Sujet(s)
Altération de l'ADN , Helicase , ADN topoisomérases de type I/génétique , Protéines Escherichia coli , Mutation , /génétique , Salmonella typhimurium/génétique , Protéines bactériennes/génétique , ADN topoisomérases de type I/métabolisme , ADN superhélicoïdal/métabolisme , Cinétique , Opéron lac , Concentration osmolaire , Salmonella typhimurium/enzymologie , Salmonella typhimurium/effets des radiations , Rayons ultravioletsRÉSUMÉ
lac operon fusions to DNA damage-inducible (din) loci were generated in Salmonella typhimurium LT2. Many of these din fusions were efficiently repressed by cloned Escherichia coli LexA, while others were not; all required RecA for induction. Several din fusions exhibited strong inducibility and will be useful in developing an SOS induction assay in S. typhimurium to detect genotoxins.
Sujet(s)
Altération de l'ADN , /physiologie , Salmonella typhimurium/génétique , Serine endopeptidases , Agents alcoylants/pharmacologie , Protéines bactériennes/pharmacologie , Clonage moléculaire , ADN/effets des médicaments et des substances chimiques , ADN/effets des radiations , Régulation de l'expression des gènes/effets des médicaments et des substances chimiques , Régulation de l'expression des gènes/effets des radiations , Gènes bactériens , Opéron lac/physiologie , Mitomycine , Mitomycines/pharmacologie , Protéines de répression/pharmacologie , Rayons ultraviolets/effets indésirables , beta-Galactosidase/biosynthèseRÉSUMÉ
UV mutability of Salmonella typhimurium LT2 was eliminated in the presence of a multicopy plasmid carrying the Escherichia coli lexA+ gene. This result suggests that inducible, SOS-like functions are required for UV mutagenesis in S. typhimurium. S. typhimurium strains carrying either point or deletion mutations in topA had previously been shown to lose their mutability by UV or methyl methanesulfonate (K. Overbye and P. Margolin, J. Bacteriol. 146:170-178, 1981; K. Overbye, S. M. Basu, and P. Margolin, Cold Spring Harbor Symp. Quant. Biol. 47:785-791, 1983). Mitomycin C induction of the phi(mucB'-lacZ') fusion (a DNA damage-inducible locus carried on plasmid pSE205) in S. typhimurium topA was normal, suggesting that RecA is activated in topA mutants. These observations lead us to deduce that S. typhimurium has at least one DNA damage-inducible locus in addition to recA that is required for UV mutability.
Sujet(s)
Réparation de l'ADN , Mutation , , Salmonella typhimurium/génétique , Serine endopeptidases , Protéines bactériennes/génétique , Gènes bactériens , Mutation/effets des radiations , Rec A Recombinases/génétique , Salmonella typhimurium/effets des radiations , Rayons ultravioletsRÉSUMÉ
In contrast to Escherichia coli and Salmonella typhimurium, Bacillus subtilis could convert ethionine to S-adenosylethionine (SAE), as can Saccharomyces cerevisiae. This conversion was essential for growth inhibition by ethionine because metE mutants which were deficient in S-adenosylmethionine synthetase activity, were resistant to 10 mM ethionine and converted only a small amount of ethionine to SAE. Another mutation (ethA1) produced partial resistance to ethionine (2 mM) and enabled continual sporulation in glucose medium containing 4 mM DL-ethionine. This sporulation induction probably resulted from the effect of SAE, since it was abolished by the addition of a metE1 mutation. The induction of sporulation was not simply controlled by the ratio of SAE to S-adenosylmethionine, but apparently depended on another effect of the ethA1 mutation, which could be demonstrated by comparing the restriction of clear plaque mutants of bacteriophage phi 105 grown in an ethA1 strain with the restriction of those grown in the standard strain. The phages grown in the ethA1 strain showed increased protection against BsuR restriction. We propose that SAE induces sporulation through the inhibition of a key methylation reaction.