RESUMEN
PREMISE OF THE STUDY: For over a century, it has been hypothesized that selection can convert an environmentally induced phenotype (i.e., plasticity) into a fixed (constitutively produced) phenotype, a process known as genetic assimilation. While evidence of assimilation is accumulating, the role of plasticity generally and assimilation specifically in evolutionary diversification has rarely been examined from a comparative phylogenetic perspective. ⢠METHODS: We combined experimental analyses of plasticity with ancestral state reconstructions to examine the evolutionary dynamics of sexual expression in two well-characterized sections (Acanthophora and Lasiocarpa) in Solanum subgenus Leptostemonum. We examined sexual expression phenotypes and the proportion of staminate flowers produced under contrasting resource conditions in 10 species and combined these data with previous studies. ⢠KEY RESULTS: Staminate flower production was phenotypically plastic for nine of 14 species and unaffected by treatment in five species. Two of the nonplastic species bore few staminate flowers, and three constitutively produced large numbers of staminate flowers. For individuals and species producing staminate flowers, these flowers occurred in a distinctive architectural pattern that was qualitatively the same in both plastic and nonplastic species. Parsimony and Bayesian reconstructions demonstrate that plasticity is ancestral among the species studied. ⢠CONCLUSIONS: Plasticity has been lost independently in sections Acanthophora and Lasiocarpa, and the consequence of its loss results in evolutionary diversification of sexual expression. In section Acanthophora, loss of plasticity represents a reversion to production of predominantly hermaphroditic flowers. In contrast, the fixed production of staminate flowers in Lasiocarpa has the hallmarks of evolution via genetic assimilation.
Asunto(s)
Evolución Biológica , Fenómenos Fisiológicos de las Plantas/genética , Solanum/genética , Solanum/fisiología , Filogenia , Reproducción/genética , Reproducción/fisiologíaRESUMEN
BACKGROUND: Nearly half of adults in the United States use complementary and alternative therapies each year for a variety of reasons. These therapies are increasingly popular among women seeking alternatives to treatment with estrogen for managing menopausal symptoms. The objective of this review was to assess the effectiveness of complementary and alternative therapies in the management of menopausal symptoms. DATA SOURCES: MEDLINE, PsychINFO, Cochrane Library database, MANTIS, and AMED. STUDY SELECTION: Full-text, English-language, randomized controlled trials and meta-analyses comparing a complementary or alternative therapy with placebo or control for treatment of menopausal symptoms. DATA EXTRACTION: All eligible trials were reviewed, abstracted into evidence tables, and rated for quality. DATA SYNTHESIS: Seventy randomized controlled trials met inclusion criteria. Forty-eight studies of phytoestrogens and other biologically based agents showed mixed results. Smaller numbers of studies using mind-body, energy, manipulative, and body-based therapies and whole medical systems showed little benefit in treating menopausal symptoms. CONCLUSIONS: Although individual trials suggest benefits from certain therapies, data are insufficient to support the effectiveness of any complementary and alternative therapy in this review for the management of menopausal symptoms. Many of these potential therapies warrant further study in trials with rigorous scientific designs to determine benefit and safety.
Asunto(s)
Terapias Complementarias/métodos , Sofocos/terapia , Menopausia/fisiología , Terapia Conductista , Femenino , Humanos , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del TratamientoRESUMEN
CONTEXT: Concern regarding the adverse effects of estrogen and other hormones for treating menopausal symptoms has led to demand for other options; however, the efficacy and adverse effects of nonhormonal therapies are unclear. OBJECTIVE: To assess the efficacy and adverse effects of nonhormonal therapies for menopausal hot flashes by reviewing published randomized controlled trials. DATA SOURCES: MEDLINE (1966-October 2005), PsycINFO (1974-October 2005), and the Cochrane Controlled Clinical Trials Register Database (1966-October 2005) were searched for relevant trials that provided data on treatment of menopausal hot flashes using 1 or more nonhormonal therapies. STUDY SELECTION: All English-language, published, randomized, double-blind, placebo-controlled trials of oral nonhormonal therapies for treating hot flashes in menopausal women measuring and reporting hot flash frequency or severity outcomes. DATA EXTRACTION: Trials were identified, subjected to inclusion and exclusion criteria, and reviewed. Data on participants, interventions, and outcomes were extracted and trials were rated for quality based on established criteria. A meta-analysis was conducted for therapies with sufficient trials reporting hot flash frequency outcomes. DATA SYNTHESIS: From 4249 abstracts, 43 trials met inclusion criteria, including 10 trials of antidepressants, 10 trials of clonidine, 6 trials of other prescribed medications, and 17 trials of isoflavone extracts. The number of daily hot flashes decreased compared with placebo in meta-analyses of 7 comparisons of selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) (mean difference, -1.13; 95% confidence interval [CI], -1.70 to -0.57), 4 trials of clonidine (-0.95; 95% CI, -1.44 to -0.47), and 2 trials of gabapentin (-2.05; 95% CI, -2.80 to -1.30). Frequency was not reduced in meta-analysis of trials of red clover isoflavone extracts and results were mixed for soy isoflavone extracts. Evidence of the efficacy of other therapies is limited due to the small number of trials and their deficiencies. Trials do not compare different therapies head-to-head and relative efficacy cannot be determined. CONCLUSION: The SSRIs or SNRIs, clonidine, and gabapentin trials provide evidence for efficacy; however, effects are less than for estrogen, few trials have been published and most have methodological deficiencies, generalizability is limited, and adverse effects and cost may restrict use for many women. These therapies may be most useful for highly symptomatic women who cannot take estrogen but are not optimal choices for most women.