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2.
Sci Rep ; 12(1): 9374, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35672342

RESUMO

Evidence-based practice (EBP) means integrating the best available scientific evidence with clinical experience and patient values. Although perceived as important by many psychotherapists, there still seems to be reluctance to use empirically supported therapies in clinical practice. We aimed to assess the attitudes of psychotherapists in Austria toward EBP in psychotherapy as well as factors influencing the implementation of EBP. We conducted an online survey. To investigate attitudes toward EBP, we used two subscales ("Limitations" and "Balance") of a translated and validated short version of the Evidence-Based Practice Attitude Scale-36 (EBPAS-36). Participants provided perceived barriers and facilitators as answers to open-ended questions. We analyzed the responses mainly using descriptive statistics. Open answers were analyzed using a thematic analysis. In total, 238 psychotherapists completed our survey (mean age 51.0 years, standard deviation [SD] = 9.9, 76.9% female). Psychotherapists scored on average 2.62 (SD = 0.89) on the reversed EBPAS-36 subscale "Limitations," indicating that the majority do not perceive EBP as limiting their practice as psychotherapists. They scored 1.43 (SD = 0.69) on the reversed EBPAS-36 subscale "Balance," indicating that psychotherapists on average put a higher value on the art of psychotherapy than on evidence-based approaches. Organizational factors such as lack of time and access to research studies as well as negative attitudes toward research and a lack of skills and knowledge kept respondents from implementing EBP. Our study highlights that EBP is still not very popular within the psychotherapy community in Austria. The academization of psychotherapy training might change this in the future.


Assuntos
Atitude do Pessoal de Saúde , Psicoterapeutas , Áustria , Estudos Transversais , Prática Clínica Baseada em Evidências , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários
4.
J Clin Epidemiol ; 139: 287-296, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34091021

RESUMO

OBJECTIVE: We aimed to map the resource use during systematic review (SR) production and reasons why steps of the SR production are resource intensive to discover where the largest gain in improving efficiency might be possible. STUDY DESIGN AND SETTING: We conducted a scoping review. An information specialist searched multiple databases (e.g., Ovid MEDLINE, Scopus) and implemented citation-based and grey literature searching. We employed dual and independent screenings of records at the title/abstract and full-text levels and data extraction. RESULTS: We included 34 studies. Thirty-two reported on the resource use-mostly time; four described reasons why steps of the review process are resource intensive. Study selection, data extraction, and critical appraisal seem to be very resource intensive, while protocol development, literature search, or study retrieval take less time. Project management and administration required a large proportion of SR production time. Lack of experience, domain knowledge, use of collaborative and SR-tailored software, and good communication and management can be reasons why SR steps are resource intensive. CONCLUSION: Resource use during SR production varies widely. Areas with the largest resource use are administration and project management, study selection, data extraction, and critical appraisal of studies.


Assuntos
Coleta de Dados , Relatório de Pesquisa , Revisões Sistemáticas como Assunto , Humanos , Pesquisa Biomédica/normas , Pesquisa Biomédica/estatística & dados numéricos , Coleta de Dados/métodos , Coleta de Dados/normas , Coleta de Dados/estatística & dados numéricos , Projetos de Pesquisa , Relatório de Pesquisa/normas , Revisões Sistemáticas como Assunto/métodos , Revisões Sistemáticas como Assunto/normas
5.
J Clin Epidemiol ; 137: 209-217, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33933579

RESUMO

OBJECTIVES: To assess the impact of restricting systematic reviews of conventional or alternative medical treatments or diagnostic tests to English-language publications. STUDY DESIGN AND SETTING: We systematically searched MEDLINE (Ovid), the Science Citation Index Expanded (Web of Science), and Current Contents Connect (Web of Science) up to April 24, 2020. Eligible methods studies assessed the impact of restricting systematic reviews to English-language publications on effect estimates and conclusions. Two reviewers independently screened the literature; one investigator performed the data extraction, a second investigator checked for completeness and accuracy. We synthesized the findings narratively. RESULTS: Eight methods studies (10 publications) met the inclusion criteria; none addressed language restrictions in diagnostic test accuracy reviews. The included studies analyzed nine to 147 meta-analyses and/or systematic reviews. The proportions of non-English-language publications ranged from 2% to 100%. Based on five methods studies, restricting literature searches or inclusion criteria to English-language publications led to a change in statistical significance in 23/259 meta-analyses (9%). Most commonly, the statistical significance was lost, but had no impact on the conclusions of systematic reviews. CONCLUSION: Restricting systematic reviews to English-language publications appears to have little impact on the effect estimates and conclusions of systematic reviews.


Assuntos
Idioma , Editoração , Editoração/estatística & dados numéricos
6.
J Clin Epidemiol ; 118: 42-54, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31698064

RESUMO

OBJECTIVES: We aimed to assess whether limiting the inclusion criteria solely to English-language publications affected the overall conclusions of evidence syntheses. STUDY DESIGN AND SETTING: Our analyses used a dataset of a previous methods study that included 59 randomly selected Cochrane intervention reviews with no language restrictions. First, we ascertained the publication language of all 2,026 included publications. Next, we excluded studies based on the following criteria: (1) publication solely in non-English language, or (2) main publication (in case of multiple publications of the same study) in non-English language. We then re-calculated meta-analyses for outcomes that were presented in the main summary of findings tables of the Cochrane reports. If the direction of the effect estimate or the statistical significance changed, authors of the respective Cochrane reviews were consulted to assess whether the new evidence base would have changed their conclusions. The primary outcome of our analyses examined the proportion of conclusions that would change with the exclusion of non-English publications. We set the threshold for the approach as noninferior if the upper limit of the 95% confidence interval of the proportion of changed conclusions did not cross a margin of 10%. RESULTS: Across all 59 Cochrane reviews, 29 (49%) included 80 non-English publications. For 16 (27%) of these Cochrane reviews, the exclusion of non-English publications resulted in the exclusion of at least one study. In the remaining 13 Cochrane reviews, the non-English publications were not the only or main publication of the study or they did not contribute to the main summary of the findings table, so their exclusion did not result in an exclusion of the study. Overall, the exclusion of non-English publications led to the exclusion of 31 studies contributing to 40 outcomes. For 38 of the 40 outcomes, the exclusion of non-English studies did not markedly alter the size or direction of effect estimates or statistical significance. In two outcomes, the statistical significance changed, but authors would have still drawn the same conclusion, albeit with less certainty. Thus, the proportion of changed conclusions in our sample was 0.0% (95% CI 0.0-0.6), which indicated the noninferiority of the approach. However, the majority of excluded studies were small. CONCLUSION: Exclusion of non-English publications from systematic reviews on clinical interventions had a minimal effect on overall conclusions and could be a viable methodological shortcut, especially for rapid reviews.


Assuntos
Estudos Epidemiológicos , Idioma , Metanálise como Assunto , Publicações/estatística & dados numéricos , Humanos , Viés de Publicação , Publicações/normas , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos
7.
BMC Psychiatry ; 17(1): 247, 2017 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-28693583

RESUMO

BACKGROUND: Seasonal affective disorder (SAD) is a seasonally recurrent type of major depression. This predictable aspect makes it promising for preventive treatment. However, evidence for the efficacy and harm of preventive treatment of SAD is scarce, as are recommendations from clinical practice guidelines. The aim of this study was to assess the current use of preventive treatment of SAD in clinical practice in German-speaking countries for the first time. METHODS: We conducted a postal and web-based survey sent to the heads of all psychiatric institutions listed in the inventory "Deutsches Krankenhaus Adressbuch, 2015" that contains all psychiatric hospitals in Germany, Austria, and Switzerland. RESULTS: One hundred institutions (out of 533 institutions, 19%), which treated in total more than 3100 SAD patients in the years 2014/2015, responded. Of those, 81 reported recommending preventive treatment to patients with a history of SAD. There was no consensus on the optimal starting point for preventive treatment. Most of the institutions that implemented prevention of SAD, recommended lifestyle changes (85%), antidepressants (84%), psychotherapy (73%), and light therapy (72%) to their patients. The situation was similar in northern and southern regions. CONCLUSIONS: Most hospitals recommended the use of preventive treatment to SAD patients, although evidence on efficacy and harm is limited. A wide variety of interventions were recommended, although guidelines only include recommendations for acute treatment. To assist psychiatrists and patients in future decision making, controlled studies on preventive treatment for SAD that compare different interventions with one another are needed.


Assuntos
Transtorno Depressivo Maior/terapia , Fototerapia/métodos , Transtorno Afetivo Sazonal/terapia , Adulto , Áustria , Feminino , Alemanha , Hospitais Psiquiátricos , Humanos , Masculino , Pessoa de Meia-Idade , Psiquiatria , Psicoterapia , Suíça
8.
J Wound Care ; 16(4): 177-82, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17444384

RESUMO

OBJECTIVE: To assess the clinical efficacy, tolerance and acceptance of a novel, hydroactive-impregnated dressing (Hydrotul) in the local treatment of acute and chronic wounds. METHOD: In a prospective observational study 24 centres in France, Belgium, Germany and Austria recruited 74 patients. At each dressing change the investigators evaluated the condition of the wound, perilesional skin and patient-reported pain. Overall, five dressing changes were documented, or until complete healing occurred. The hydroactive properties of the dressing were assessed in laboratory tests by measuring fluid absorption capacity and kinetics. RESULTS: Patients were treated for an average of 17 days. The wound condition improved markedly during the observation period. The wound area covered with fibrinous slough decreased from 29% to 14%, epithelialisation increased from 19% to 54% and 22 wounds were completely healed by the end of the study. The number of patients reporting severe and moderate wound pain decreased from 35% to 19% and the proportion of patients without wound pain doubled from 27% to 60%. In laboratory tests, Hydrotul absorbed two to three times the amount of fluid compared with other impregnated wound dressings and the kinetics of absorption was much faster. CONCLUSION: The novel hydroactive impregnated dressing supports the healing process in patients with acute and chronic wounds and reduces wound pain. The dressing absorbs excess wound exudate while keeping the wound surface moist and protecting perilesional skin.


Assuntos
Bandagens , Pomadas/uso terapêutico , Cicatrização , Absorção , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
9.
Phytomedicine ; 13(6): 452-6, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16716917

RESUMO

Inhibition of leukotriene formation is one of the approaches to the treatment of asthma and other inflammatory diseases. We have investigated knipholone, isolated from the roots of Kniphofia foliosa, Hochst (Asphodelaceae), for inhibition of leukotriene biosynthesis in an ex vivo bioassay using activated human neutrophile granulocytes. Moreover, activities on 12-lipoxygenase from human platelets and cycloxygenase (COX)-1 and -2 from sheep cotyledons and seminal vesicles, respectively, have been evaluated. Knipholone was found to be a selective inhibitor of leukotriene metabolism in a human blood assay with an IC(50) value of 4.2microM. However, at a concentration of 10microg/ml, the compound showed weak inhibition of 12(S)-HETE production in human platelets and at a concentration of 50microM it produced no inhibition of COX-1 and -2. In our attempt to explain the mechanism of inhibition, we examined the antioxidant activity of knipholone using various in vitro assay systems including free radical scavenging, non-enzymatic lipid peroxidation, and metal chelation. Knipholone was found to be a weak dose-independent free radical scavenger and lipid peroxidation inhibitor, but not a metal chelator. Therefore, the leukotriene biosynthesis inhibitory effect of knipholone was evident by its ability either to inhibit the 5-lipoxygenase activating protein (FLAP) or as a competitive (non-redox) inhibitor of the enzyme. Cytotoxicity results also provided evidence that knipholone exhibits less toxicity for a mammalian host cell.


Assuntos
Antraquinonas/farmacologia , Leucotrienos/biossíntese , Magnoliopsida , Fitoterapia , Extratos Vegetais/farmacologia , Animais , Artemia/efeitos dos fármacos , Compostos de Bifenilo , Sequestradores de Radicais Livres/farmacologia , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Picratos/química , Placenta/efeitos dos fármacos , Raízes de Plantas , Glândulas Seminais/efeitos dos fármacos , Ovinos
11.
Parasitology ; 123(Pt 2): 185-91, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11510684

RESUMO

European eels (Anguilla anguilla) from 2 sampling sites on the Rhine river (near Karlsruhe and near Worms) were investigated with respect to their parasite communities. Nine different metazoan species were found to live in and on the eels. The highest number of species was recorded from the intestine, which contained up to 6 different helminths. Among these, acanthocephalans were the most prevalent worms with the eel-specific parasite Paratenuisentis ambiguus as the dominant species of the intestinal component communities at both sites. Comparing the intestinal parasites from eels caught near Karlsruhe with those from Worms, the acanthocephalans showed a significantly lower abundance at Worms. A significantly lower mean number of intestinal helminth species as well as a significantly lower Brillouin's Index was found at Worms compared with Karlsruhe. This difference could be related to the abundance of the respective intermediate crustacean hosts. At the sampling site Worms the amphipod Corophium curvispinum was the dominant crustacean. Additionally, only the isopod Jaera istri and the amphipod Dikerogammarus villosus were found. All these crustacean species have only recently colonized the Rhine river system via the Main-Danube canal, built in the early 1990s. They are not known to act as intermediate hosts for any of the acanthocephalans found in the eels. The site near Karlsruhe exhibited a higher crustacean diversity, including Asellus aquaticus and different species of the genus Gammarus, which are all known intermediate hosts for the acanthocephalans found. Therefore, changes of eel parasite diversity can be correlated with the appearance of invading crustacean species (neozoans).


Assuntos
Anguilla/parasitologia , Doenças dos Peixes/parasitologia , Água Doce/parasitologia , Helmintíase Animal/parasitologia , Helmintos/isolamento & purificação , Animais , Crustáceos/crescimento & desenvolvimento , Doenças dos Peixes/epidemiologia , Alemanha/epidemiologia , Helmintíase Animal/epidemiologia , Helmintos/crescimento & desenvolvimento , Intestinos/parasitologia , Prevalência , Estatísticas não Paramétricas
12.
J Exp Zool ; 285(1): 63-75, 1999 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-10327652

RESUMO

The isolation of Hox genes from two cnidarian groups, the Hydrozoa and Anthozoa, has sparked hypotheses on the early evolution of Hox genes and a conserved role for these genes for defining a main body axis in all metazoan animals. We have isolated the first five Hox genes, Scox-1 to Scox-5, from the third cnidarian class, the Scyphozoa. For all but one gene, we report full-length homeobox plus flanking sequences. Four of the five genes show close relationship to previously reported Cnox-1 genes from Hydrozoa and Anthozoa. One gene, Scox-2, is an unambiguous homologue of Cnox-2 genes known from Hydrozoa, Anthozoa, and also Placozoa. Based on sequence similarity and phylogenetic analyses of the homeobox and homeodomain sequences of known Hox genes from cnidarians, we suggest the presence of at least five distinct Hox gene families in this phylum, and conclude that the last common ancestor of the Recent cnidarian classes likely possessed a set of Hox genes representing three different families, the Cnox-1, Cnox-2, and Cnox-5 families. The data presented are consistent with the idea that multiple duplication events of genes have occurred within one family at the expense of conservation of the original set of genes, which represent the three ancestral Hox gene families.


Assuntos
DNA/isolamento & purificação , Evolução Molecular , Genes Homeobox , Cifozoários/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Dados de Sequência Molecular , Filogenia , Técnica de Amplificação ao Acaso de DNA Polimórfico
13.
Ecotoxicol Environ Saf ; 39(1): 10-20, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9515070

RESUMO

The toxicity of lindane, hexachlorobenzene, and copper sulfate to Tubifex tubifex and Limnodrilus hoffmeisteri was determined using an easily applicable and standardizable 72-h short-term test system. It was designed for the quick assessment of sublethal and lethal effects of sediment-associated chemicals on the worms. An artificial sediment based on the Artificial Soil according to OECD Guideline No. 207 was used as test medium. The data confirm the common view that oligochaetes are highly tolerant of lethal effects. However, sublethal effects were detected at considerably lower concentrations than found for lethal effects. The EC50 values for autotomy (172 mg/kg dry wt sediment) and sediment avoidance (217 mg/kg) for T. tubifex exposed to lindane-contaminated sediment were, for example, more than five times lower than the LC50 value (> 1000 mg/kg). The no-observed-effect concentration for reworking activity (8 mg/kg) was more than 125 times lower than the LC50. Tubificids thus turned out to represent useful test organisms for the assessment of the ecotoxicological hazard potential of chemicals in the sediment compartment, because the sublethal effects not only affect the individual, but can influence the population levels and, consequently, the composition of the benthic community.


Assuntos
Sulfato de Cobre/toxicidade , Fungicidas Industriais/toxicidade , Hexaclorobenzeno/toxicidade , Hexaclorocicloexano/toxicidade , Inseticidas/toxicidade , Oligoquetos/efeitos dos fármacos , Animais , Meios de Cultura , Relação Dose-Resposta a Droga , Dose Letal Mediana , Locomoção/efeitos dos fármacos , Sensibilidade e Especificidade , Poluentes do Solo/análise , Testes de Toxicidade/métodos
14.
EXS ; 86: 353-87, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9949881

RESUMO

The term bioaccumulation is defined as uptake, storage, and accumulation of organic and inorganic contaminants by organisms from their environment. Bioaccumulation therefore results from complex interactions between various routes of uptake, excretion, passive release, and metabolization. For fish, the bioaccumulation process includes two routes of uptake: aqueous uptake of water-borne chemicals, and dietary uptake by ingestion of contaminated food particles. The contribution to bioaccumulation that results from aqueous exposure and is taken up by the gills is called bioconcentration. The contribution to bioaccumulation resulting from dietary exposure via uptake by intestinal mucosa is termed biomagnification. In both cases, important co-determinants for bioaccumulation are the various elimination mechanisms. This chapter presents a short historical survey of the problem of bioaccumulation with particular reference to fish and of the various approaches to study bioaccumulation. This is followed by an overview of our present knowledge about basic physico-chemical determinants that either increase or reduce the bioaccumulation potential of various chemicals, and about the physiological basis of gills, blood circulation and intestines, as far as they are crucial for our understanding of uptake and accumulation. Finally, selected quantitative data and modelings of bioaccumulation in fish will be discussed, with regard to such problems as the relative importance of aqueous and dietary uptake.


Assuntos
Peixes/metabolismo , Poluentes Químicos da Água/farmacocinética , Animais , Biodegradação Ambiental
15.
Cytokine ; 8(10): 751-61, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8980876

RESUMO

A radicicol analogue (analogue A) was found to inhibit interleukin 1 beta (IL-1 beta) and tumour necrosis factor alpha (TNF-alpha) secretion from THP-1 cells. If added to cells activated by interferon gamma and lipopolysaccharide, radicicol analogue A not only inhibited the secretion of IL-1 beta but also induced an extremely rapid degradation of IL-1 beta, IL-6 and TNF-alpha mRNA to undetectable levels within 5-8 h. This degradation is independent of translation and of the signal inducing transcription. The common feature of these genes is the inclusion of one or more copies of the mRNA-instability sequence, AUUUA, in the 3' untranslated region. Indeed, no destabilizing effect of radicicol analogue A could be observed on mRNA derived from the expression of an IL-1 beta construct lacking the AUUUA motifs of the 3'UTR. The effect of radicicol analogue A on protein/mRNA interaction and on post-translational modifications of cytoplasmic proteins is described. This class of compound constitutes a valuable tool for the further elucidation of the mechanism of mRNA degradation of cytokines and proto-oncogenes.


Assuntos
Interleucina-1/genética , Lactonas/química , RNA Mensageiro/metabolismo , Sequência de Bases , Clonagem Molecular , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Ensaio de Imunoadsorção Enzimática , Humanos , Interleucina-1/metabolismo , Lactonas/farmacologia , Lipopolissacarídeos/farmacologia , Macrolídeos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Relação Estrutura-Atividade , Células Tumorais Cultivadas
16.
Mol Phylogenet Evol ; 6(1): 30-8, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8812303

RESUMO

In order to test current hypotheses on the early evolution of Antp-class (HOM/Hox) genes in metazoan animals, we surveyed the diploblastic hydrozoan Eleutheria dichotoma for the presence of these genes. By means of PCR with different sets of degenerate primers, three new homeobox sequences were identified, in addition to two previously found fragments. Following RACE amplification of the 3' and 5' flanking regions, we classified all five genes, Cnox-1 to Cnox-5, as belonging to the Antp-class. Homeodomain identity to the most similar HOM/Hox genes from Drosophila and human ranges from 58 to 72%. Each of the Cnox genes contains diagnostic residues of more than one Antp-class family known from triploblastic animals. These data are at odds with a previously proposed ancestral HOM/Hox cluster composition, with respect to both the number and types of Antp-class homeobox genes found.


Assuntos
Cnidários/genética , Evolução Molecular , Genes Homeobox , Proteínas de Homeodomínio/genética , Proteínas Nucleares , Fatores de Transcrição , Sequência de Aminoácidos , Animais , Proteína do Homeodomínio de Antennapedia , Sequência de Bases , Clonagem Molecular , DNA , Humanos , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos
17.
Mol Ecol ; 5(3): 437-41, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8688961

RESUMO

Simple sequence repeats (SSRs, or microsatellites) have been constantly gaining importance as single-locus DNA markers in population genetics and behavioural ecology. We tested a PCR-based strategy for finding microsatellite loci in anonymous genomes, which avoids genomic library construction and screening, and the need for larger amounts of DNA. In the first step, parts of a genome are randomly amplified with arbitrary 10mer primers using RAPD fingerprinting. Labelled SSR-oligonucleotides serve as probes to detect complementary sequences in RAPD products by means of Southern analyses. Subsequently, positive RAPD fragments of suitable size are cloned and sequenced. Using GA and GT probes, we applied this approach to waterfleas (Daphnia) and revealed 37 hybridization signals in 20 RAPD profiles. Thirteen positive RAPD fragments from three Daphnia species and two hybrid 'species' were cloned and sequenced. In all cases simple sequence repeats were detected. We characterized seven perfect repeat loci, which were found to be polymorphic within and between species.


Assuntos
DNA Satélite/genética , Daphnia/genética , Repetições de Microssatélites/genética , Polimorfismo Genético , Técnica de Amplificação ao Acaso de DNA Polimórfico , Animais , Sequência de Bases , Evolução Biológica , Primers do DNA , Biblioteca Genômica , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos
18.
J Comput Biol ; 3(2): 235-51, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8811485

RESUMO

The polymerase chain reaction (PCR) has become an indispensable tool in modern biological research. Although the application of PCR is a standard routine, we widely lack a theoretical understanding of the dynamic processes involved, especially with respect to the amplification of nonreproducible and/or unexpected amplification products. For one potential source of uncertainty, the presence of nested primer binding sites within an amplifyable DNA locus, we consider a simple stochastic model for the dynamics of PCR amplification of competing products. For commonly used thermostable DNA polymerases lacking a 5'-3'-exonuclease activity, we predict the relative amplification frequencies of competing PCR products dependent on the primer binding probability, the number of PCR cycles, and the number of initial DNA template molecules. At low primer binding probabilities and low numbers of initial DNA template molecules and PCR cycles, we expect the amplification of two products. At high primer binding probabilities and/or high copy numbers of initial template molecules only one main amplification product is predicted at increasing cycle numbers. Furthermore, by means of computer simulation studies we quantify the stochastic variation for the amplification frequencies of competing products.


Assuntos
Simulação por Computador , Modelos Teóricos , Reação em Cadeia da Polimerase/estatística & dados numéricos , Bacteriófago lambda/genética , Sequência de Bases , DNA/genética , Primers do DNA , DNA Viral/genética , Modelos Genéticos , Técnica de Amplificação ao Acaso de DNA Polimórfico/estatística & dados numéricos , Reprodutibilidade dos Testes , Software , Processos Estocásticos
19.
Proc Biol Sci ; 262(1364): 119-25, 1995 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-8524906

RESUMO

We estimated outcrossing rates and correlated matings in a natural population of the hermaphroditic freshwater snail Ancylus fluviatilis, using progeny arrays and polymorphic allozyme markers. This design circumvents drawbacks of earlier studies, and yields maximum likelihood estimates of outcrossing rates at both the individual and population level. Adult snails were sampled during the spring breeding period, allowing for prior copulations and sperm transfer under natural conditions. Once in the laboratory, they were kept isolated for 21 days and laid egg capsules, and emerging hatchlings from 42 families were scored for five polymorphic loci. 87 of 848 offspring exhibited non-maternal alleles, representing a minimum population-level outcrossing of 10.3%. Maximum likelihood estimates are in the range 13-15%. Importantly, there is significant among-family heterogeneity, as only 16 of 42 families are estimated to have outcrossed, in accord with high estimates of correlated selfing within progeny arrays. Moreover, the high proportion of full sibs among outcrossed sibs suggests a limited extent of multiple paternity. Our data reveal important heterogeneity in the mating system of an animal hermaphrodite, and indicate the potential for evolutionary change in the breeding system.


Assuntos
Comportamento Sexual Animal , Caramujos/fisiologia , Animais , Água Doce
20.
Environ Sci Pollut Res Int ; 2(4): 194-9, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24234684

RESUMO

We analyzed six organochlorine compounds (HCB, lindane, p,p'-DDE, PCB # 138, #153, and # 180) from populations of the European great tit (Parus major) and from five species of bats (Pipistrellus pipistrellus, Nyctalus noctula, Plecotus auritus, Plecotus austriacus, Myotis myotis). A weak positive correlation between Kow (n-octanol /water partition coefficient) and bioaccumulation (measured as residue values) was found within each species. However, the ratio of the concentrations in bats compared to titmice increased significantly with increasing Kow. We argue that this is explained by the intensive juvenile feeding through long-term lactation and thus by the more intensive transfer of strongly lipophilic xenobiotics from mother to juvenile in mammals compared to birds. Further, there were clear variations between bat species with ranges of up to 11 times the lowest value for a single compound. These differences are related to different feeding habits of the adults and to different species-specific life history traits, such as age at maturity and number of offspring.

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