ABSTRACT
Os métodos contraceptivos desempenham um papel vital na saúde sexual e reprodutiva, oferecendo opções que permitem o planejamento familiar e a prevenção de gravidezes indesejadas. Este artigo busca descrever os benefícios e desvantagens dos principais anticoncepcionais presentes na atualidade por meio de uma revisão integrativa da literatura, que buscou identificar os achados científicos publicados nos últimos 10 anos (2013 a fevereiro de 2023). A seleção de artigos foi feita nas bases eletrônicas de dados da PubMed, BVS, SciELO e no Google Acadêmico. Para a realização da revisão integrativa foi estabelecida a pergunta norteadora, para possibilitar a busca na base dados: Quais os benefícios e as desvantagens dos anticoncepcionais adesivo combinado, anel vaginal, sistema intrauterino de liberação de Levonorgestrel (SIU-LNG), contracepção de emergência (pílula de emergência), implante hormonal e anticoncepcional oral (ACO). Um dos pontos mais notáveis nesta revisão foi a grande variedade de métodos contraceptivos e suas peculiaridades, que se adequam à necessidade da usuária, sendo, portanto, preciso uma análise cuidadosa do método a ser escolhido. Outro ponto de destaque, foi que apesar dos benefícios dos contraceptivos, também estão presentes os efeitos adversos e possíveis complicações, além das precauções em sua utilização.
Contraceptive methods play a vital role in sexual and reproductive health, offering options that allow for family planning and the prevention of unwanted pregnancies. This article seeks to describe the benefits and disadvantages of the main contraceptives currently available through an integrative literature review, which sought to identify scientific findings published in the last 10 years (2013 to February 2023). The selection of articles was made in the electronic databases of PubMed, VHL, SciELO and Google Scholar. To carry out the integrative review, the guiding question was established, to enable the search in the database: What are the benefits and disadvantages of contraceptives combined patch, vaginal ring, Levonorgestrel-releasing intrauterine system (LNG-IUS), emergency contraception (emergency pill), hormonal implant and oral contraceptive (OC). One of the most notable points in this review was the wide variety of contraceptive methods and their peculiarities, which adapt to the user's needs, therefore requiring a careful analysis of the method to be chosen. Another highlight was that despite the benefits of contraceptives, adverse effects and possible complications are also present, in addition to precautions in their use.
Los métodos anticonceptivos desempeñan un papel vital en la salud sexual y reproductiva, ofreciendo opciones que permiten la planificación familiar y la prevención de embarazos no deseados. Este artículo busca describir los beneficios y desventajas de los principales anticonceptivos actualmente disponibles a través de una revisión integrativa de la literatura, que buscó identificar hallazgos científicos publicados en los últimos 10 años (2013 a febrero de 2023). La selección de artículos se realizó en las bases de datos electrónicas PubMed, BVS, SciELO y Google Scholar. Para realizar la revisión integradora se estableció la pregunta orientadora, para posibilitar la búsqueda en la base de datos: Cuáles son los beneficios y desventajas de los anticonceptivos combinados parche, anillo vaginal, sistema intrauterino liberador de levonorgestrel (SIU-LNG), anticoncepción de emergencia (emergencia píldora), implante hormonal y anticonceptivo oral (AO). Uno de los puntos más destacables de esta revisión fue la gran variedade de métodos anticonceptivos y sus peculiaridades, que se adaptan a las necesidades del usuario, requiriendo por tanto un análisis cuidadoso del método a elegir. Otro destaque fue que a pesar de los beneficios de los anticonceptivos, también están presentes efectos adversos y posibles complicaciones, además de precauciones en su uso.
ABSTRACT
The meiotic behaviour of three three-way interspecific promising hybrids (H17, H27, and H34) was evaluated. These hybrids resulted from the crosses between B. ruziziensis X B. brizantha and crossed to another B. brizantha. Two half-sib hybrids (H27 and H34) presented an aneuploid chromosome number (2n = 4x = 33), whereas hybrid H17 was a tetraploid (2n = 4x = 36), as expected. Chromosome paired predominantly as multivalents suggesting that genetic recombination and introgression of specific target genes from B. brizantha into B. ruziziensis can be expected. Arrangement of parental genomes in distinct metaphase plates was observed in H27 and H34, which have different male genitors. Hybrids H17 and H34 have the same male genitor, but did not display this abnormality. In H17, abnormalities were more frequent from anaphase II, when many laggard chromosomes appeared, suggesting that each genome presented a different genetic control for meiotic phase timing. Despite the phylogenetic proximity among these two species, these three hybrids presented a high frequency of meiotic abnormalities, mainly those related to irregular chromosome segregation typical of polyploids, H34, 69.1%; H27, 56.1% and H17, 44.9%. From the accumulated results obtained through cytological studies in Brachiaria hybrids, it is evident that cytogenetical analysis is of prime importance in determining which genotypes can continue in the process of cultivar development and which can be successfully used in the breeding. Hybrids with high frequency of meiotic abnormalities can seriously compromise seed production, a key trait in assuring adoption of a new apomictic cultivar of Brachiaria for pasture formation.
Subject(s)
Animal Feed , Brachiaria/classification , Breeding , Genome, Plant , Hybridization, Genetic , Meiosis/genetics , Ploidies , Species SpecificityABSTRACT
Chromosome number and meiotic behavior were evaluated in 36 Brazilian accessions of the grass Paspalum (which had never previously been analyzed) to determinate which accessions might be useful in interspecific hybridizations. The analysis showed that one accession of Paspalum coryphaeum was diploid (2n = 2x = 20) and one accession of Paspalum conspersum hexaploid (2n = 6x = 60), the remaining 34 accessions being tetraploid (2n = 4x = 40). The pairing configuration was typical for the ploidy level i.e. in the diploid, chromosomes paired as 10 bivalents, in tetraploids as bi-, tri- and quadrivalents, and in hexaploid as 30 bivalents. A low frequency of meiotic abnormalities (less than 10%) was observed in the diploid, hexaploid and some tetraploid accessions, although the majority of tetraploid accessions showed a high frequency of meiotic irregularities. The use of accessions with a low frequency of meiotic abnormalities in breeding programs is discussed