Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 81
Filtrar
1.
Rural Remote Health ; 23(4): 8227, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37988704

RESUMEN

INTRODUCTION: Sexual and gender minority people who live in rural areas are less likely to have had a HIV test in the previous 12 months compared with those who live in non-rural areas. We assessed the independent contribution of distance and time required to travel to receive a HIV test on recent uptake of HIV testing. METHODS: We conducted a cross-sectional survey of sexual and gender minority populations in the southern US. We used Poisson regression with robust standard errors to estimate prevalence ratios to compare uptake of HIV testing in the previous 12 months among those who traveled more than 20 miles (~32 km) and more than 30 minutes to their most recent HIV test compared with those who traveled less distance and time to their most recent test, respectively. RESULTS: A total of 508 (n=155 rural, n=348 non-rural) participants completed the survey. Of these, 398 (78.5%) had received a HIV test in the previous 12 months. Those who traveled more than 20 miles (~32 km) to their most recent test were more likely to have not received a HIV test in the previous 12 months compared with those who traveled 20 miles (~32 km) or less (adjusted prevalence ratio 2.25; 95% confidence interval 1.22-4.17). There were no differences based on travel time to the most recent test. CONCLUSION: Distance, but not time, to travel to receive a HIV test is independently associated with reduced HIV testing. More geographically proximal options or access to home-based testing might reduce this barrier.


Asunto(s)
Infecciones por VIH , Minorías Sexuales y de Género , Humanos , Estudios Transversales , Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , Conducta Sexual , Prueba de VIH
2.
Sci Rep ; 13(1): 18082, 2023 10 23.
Artículo en Inglés | MEDLINE | ID: mdl-37872353

RESUMEN

Physiological stress levels in response to sexual behavior stigma among men who have sex with men (MSM) in the United States (US) are understudied. The current study aims to explore the relationship between sexual behavior stigma and salivary cortisol both overall and stratified by race/ethnicity. If such an association exists, it may suggest that sexual behavior stigma can be physiologically measured or indicated by the presence of heightened salivary cortisol. A subsample of 667 MSM participants from the 2019 American Men's Internet Survey (AMIS; N = 10,129) submitted morning (AM) and evening (PM) saliva cortisol samples using at-home mail-in collection kits. Average daily cortisol and daily cortisol change were calculated; simple linear regressions estimated associations between cortisol measures and sexual behavior stigma characterized in four different ways (ever and recent experience of individual stigma items; average ever and recent experience of three stigma scales: stigma from family and friends, anticipated healthcare stigma, general social stigma). Participants reported a mean age of 36.0 years (SD = 14.9), with most being non-Hispanic white (n = 480, 72.0%), Hispanic (n = 164, 12.3%), or Black/African American (n = 146, 10.9%), and identified as homosexual/gay (n = 562, 84.3%). Reporting ever experiencing healthcare providers gossiping was significantly associated with higher PM cortisol (ß = 0.12, p = 0.001) and higher average daily cortisol (ß = 0.11, p = 0.004), while reporting ever experiencing police refusing to protect was associated with higher AM cortisol (ß = 0.08, p = 0.03) and higher average daily cortisol (ß = 0.09, p = 0.02). Recent experiences of stigma were not significant predictors of any measure of cortisol. Measures of salivary cortisol may be used to characterize sexual behavior stigma among MSM populations, however more insight is needed to determine its exact relationship and strength.


Asunto(s)
Infecciones por VIH , Minorías Sexuales y de Género , Masculino , Humanos , Estados Unidos , Adulto , Homosexualidad Masculina , Hidrocortisona , Estigma Social , Conducta Sexual , Internet
3.
Subst Use Misuse ; 58(5): 728-734, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36872623

RESUMEN

Background: Chemsex is the intentional use of drugs to enhance sexual activity. Chemsex drug use among men who have sex with men (MSM) is associated with sexual behaviors that increase sexually transmitted infection (STI) risks and adverse mental health outcomes. However, published data are largely based on MSM recruited from STI clinics. There are limited data about use of chemsex drugs among national samples of MSM in the United States. Using data from the American Men's Internet Survey (AMIS), we assessed the prevalence and correlates of use of chemsex drugs among sexually active MSM in the United States. Methods: We used data from the 2017 to 2020 AMIS cycles to examine the prevalence of chemsex drug use in the past 12 months among MSM. We calculated prevalence ratios (PR) and 95% confidence intervals (CI) to compare chemsex drug use across demographic, behavioral, and mental health factors. Results: Of 30,294 MSM, 3,113 (10.3%) reported chemsex drug use in the past 12 months. Of the 3,113 MSM who reported chemsex drug use, 65.1% reported ecstasy use, 42.5% reported crystal methamphetamine use, and 21.7% reported GHB use. Factors associated with chemsex drug use included condomless anal sex (PR = 1.93, 95%=1.69-2.20), problem drinking (PR = 2.36, 95% = 2.13-2.61), bacterial STI test (1.84, 95% CI = 1.68-2.02) and probable serious mental illness (PR = 1.92, 95% = 1.76-2.09). Conclusion: Chemsex drug use is associated with behaviors that increase STI risk and mental distress among MSM. Health programs that serve MSM can consider screening for chemsex drug use and offering sexual and mental health promotion and risk reduction interventions when necessary.


Asunto(s)
Infecciones por VIH , Minorías Sexuales y de Género , Enfermedades de Transmisión Sexual , Trastornos Relacionados con Sustancias , Masculino , Humanos , Estados Unidos/epidemiología , Homosexualidad Masculina/psicología , Conducta Sexual/psicología , Enfermedades de Transmisión Sexual/epidemiología , Trastornos Relacionados con Sustancias/psicología , Infecciones por VIH/epidemiología
4.
Sex Transm Dis ; 50(7): 458-461, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-36940183

RESUMEN

ABSTRACT: Mpox vaccination is recommended for persons exposed to or at risk for mpox. Approximately 25% of an online sample of men who have sex with men (MSM) with presumed mpox exposure were vaccinated (≥1 dose). Vaccination was higher among younger MSM, MSM concerned about mpox, or MSM reporting sexual risk behaviors. Incorporating mpox vaccination into routine sexual health care and increasing 2-dose vaccination uptake is essential to preventing mpox acquisition, improving MSM sexual health, and averting future mpox outbreaks.


Asunto(s)
Mpox , Minorías Sexuales y de Género , Vacuna contra Viruela , Masculino , Humanos , Homosexualidad Masculina , Conducta Sexual , Vacunación
5.
J Int AIDS Soc ; 26(3): e26077, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36951057

RESUMEN

INTRODUCTION: Long-acting injectable (LAI) pre-exposure prophylaxis (PrEP) for HIV prevention was approved by the U.S. Food and Drug Administration in 2021. LAI PrEP is more effective than oral PrEP. However, it is not clear whether the groups most at risk of HIV in the United States will use LAI PrEP. Willingness to use LAI PrEP and preference for LAI versus oral PrEP has not been reported for sexual and gender minority (SGM) people in the southern United States, where the HIV epidemic is concentrated. Our goal was to assess willingness to use LAI PrEP and preference for oral versus LAI PrEP among SGM people in the southern United States and to assess differences in willingness by demographics and sexual behaviour. METHODS: We conducted an online, cross-sectional survey of SGM people aged 15-34 years in the southern United States (n = 583). Participants reported willingness to use LAI PrEP and preferences for LAI PrEP versus daily oral PrEP. We assessed bivariate associations and adjusted prevalence ratios for the LAI-PrEP-related outcomes and key demographic and behavioural characteristics. RESULTS: Overall, 68% of all participants (n = 393) reported being willing to use LAI PrEP that provides protection against HIV for 3 months. Of those, most (n = 320, 81%) indicated a preference for using LAI PrEP, compared to a daily oral pill or no preference. Willingness to use LAI PrEP was more common among transgender and non-binary participants and participants who engaged in condomless anal intercourse in the last 6 months. Hispanic participants were more likely and non-Hispanic Black participants were less likely to report willingness to use LAI PrEP compared to non-Hispanic White participants. CONCLUSIONS: Willingness to use LAI PrEP was high among SGM people in the southern United States, although there were some important differences in willingness based on demographic characteristics. Decreased willingness to use LAI PrEP among groups who are disproportionately affected by the HIV epidemic, such as non-Hispanic Black SGM people, could exacerbate existing disparities in HIV incidence. LAI PrEP is an acceptable option among SGM populations in the southern United States, but strategies will be needed to ensure equitable implementation.


Asunto(s)
Fármacos Anti-VIH , Infecciones por VIH , Profilaxis Pre-Exposición , Minorías Sexuales y de Género , Masculino , Humanos , Estados Unidos , Estudios Transversales , Homosexualidad Masculina , Infecciones por VIH/prevención & control , Infecciones por VIH/epidemiología , Aceptación de la Atención de Salud , Conducta Sexual
6.
AIDS Behav ; 27(9): 2815-2822, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36738343

RESUMEN

A number of mobile HIV prevention interventions have been developed to increase uptake of HIV prevention services such as HIV testing and pre-exposure prophylaxis (PrEP). Most of these interventions have been tested among urban populations. However, sexual and gender minority (SGM) groups in rural areas might also benefit from mobile HIV prevention interventions. These groups have heightened experiences of stigma and discrimination and have limited access to culturally competent healthcare. We conducted a survey of SGM participants in the southern United States to assess willingness to use the common features of mobile HIV prevention interventions and to participate in research studies of these interventions and to compare the results between rural and non-rural respondents. We found few differences in willingness to use common features of mobile HIV prevention interventions based on rurality and high levels of cellular connectivity across participants. Based on these results, rural residence is not a barrier to using mobile HIV prevention interventions.


Asunto(s)
Infecciones por VIH , Profilaxis Pre-Exposición , Minorías Sexuales y de Género , Telemedicina , Humanos , Estados Unidos/epidemiología , Masculino , Estudios Transversales , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Conducta Sexual , Homosexualidad Masculina
7.
PLoS One ; 18(2): e0280787, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36735687

RESUMEN

INTRODUCTION: Sexual and gender minority (SGM) communities, including lesbian, gay, bisexual, transgender, queer, intersex, asexual, and Two-Spirit people, have historically been researched from a deficits-based approach that fails to highlight the ways communities survive and thrive in the face of adversity. This study endeavored to create a model of resources that promote SGM resilience using a sample that amplified traditionally underrepresented perspectives, including individuals from racial and/or ethnic minority groups, trans and/or gender diverse individuals, individuals on the asexual spectrum, and older adults. METHODS: Participant responses to three open-ended questions from The PRIDE Study's (an online national longitudinal cohort study of SGM people) 2018 Annual Questionnaire were analyzed using constructivist grounded theory. These questions examined what brings people joy and what they appreciate most about their SGM identity. Participants (n = 315) were randomly selected from a larger sample of people who had responded to demographic questions and at least one open-ended question (N = 4,030) in a manner to ensure diverse representation across race/ethnicity, gender identity, sexual orientation, age, and region of residence. RESULTS: The proposed model includes social resources (Connecting with Others, Cultivating Family, Helping Others, Participating in Culture and Spirituality), affective generative resources (Engaging in Enriching Pursuits, Accessing Economic Resources), and introspective resources (Exploring One's Authentic Self, Persevering through Hardship) that are theorized to contribute to SGM resilience across the life course. CONCLUSIONS: SGM communities may tap into various resources to promote resilience. As public health practitioners, we can help to foster this resilience by resourcing and supporting initiatives that foster social connection, create spaces for community members to engage with various types of enrichment, facilitate access to economic resources, and provide support and inclusion for all SGM community members.


Asunto(s)
Identidad de Género , Minorías Sexuales y de Género , Humanos , Masculino , Femenino , Anciano , Etnicidad , Estudios Longitudinales , Teoría Fundamentada , Grupos Minoritarios/psicología , Conducta Sexual
9.
JMIR Form Res ; 6(6): e38075, 2022 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-35699980

RESUMEN

BACKGROUND: Mobile health (mHealth) interventions, including smartphone apps, have been found to be an effective means of increasing the uptake of HIV prevention tools, including HIV and sexually transmitted infection (STI) tests and pre-exposure prophylaxis. However, most HIV prevention mHealth apps tested in the United States have been tested among populations living in areas surrounding urban centers. Owing to reduced access to broadband internet and reliable cellular data services, it remains unclear how accessible and effective these interventions will be in rural areas. In addition, gay and bisexual men who have sex with men and gender minority populations in rural areas experience enhanced stigma when compared with their more urban counterparts, and these experiences might affect their willingness and interest in mHealth apps. OBJECTIVE: This study aimed to conduct online focus groups with men who have sex with men and transgender and gender diverse populations in the rural southern United States to assess their interest in mHealth HIV prevention apps and the features that they would be the most interested in using. METHODS: Focus group participants were recruited from a larger pool of sexual and gender minority respondents to a web-based research survey. The participants indicated that they would be willing to participate in an online focus group discussion. Focus groups were conducted via secure Zoom (Zoom Video Communications Inc) videoconferencing. During the focus group discussions, participants were asked to discuss their experiences with HIV and STI prevention and how these experiences were affected by living in a rural area. They were then shown screenshots of a new app to promote HIV and STI prevention among rural populations and asked to provide their opinions on the app's features. The transcripts of the discussions were reviewed and coded using a constant comparative approach. RESULTS: A total of 6 focus groups were conducted with 26 participants. Most participants were cisgender gay and bisexual men who have sex with men (19/26, 73%); the remaining participants were transgender men (2/26, 8%), were nonbinary people (2/26, 8%), or had multiple gender identities (3/26, 12%). Participants reported numerous barriers to accessing HIV and STI prevention services and accurate information about HIV and STI prevention options. Overall, the participants reported a high degree of interest in mHealth interventions for HIV and STI prevention and suggested several recommendations for the features of an app-based intervention that would be the most useful for rural residents. CONCLUSIONS: These focus group discussions indicate that rural residence is not a major barrier to mHealth HIV and STI prevention intervention implementation and that there is a high degree of interest in these approaches to HIV and STI prevention.

10.
J Econ Entomol ; 115(1): 143-150, 2022 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-35139214

RESUMEN

Globally, 27 aphid species have evolved resistance to almost 100 insecticide active ingredients. A proactive approach to resistance management in pest aphids is needed; this should include risk analysis, followed by regular baseline susceptibility assays for species deemed at high risk of evolving resistance. The cowpea aphid (Aphis craccivora Koch) has evolved insecticide resistance to multiple insecticides outside Australia and was recently identified as a high-risk species in Australia. In this study, we generated toxicity data against four insecticides (representing four unique chemical Mode of Action groups) for populations of A. craccivora collected across Australia. Alpha-cypermethrin was the most toxic chemical to A. craccivora in leaf-dip laboratory bioassays with an average LC50 value across nine populations of 0.008 mg a.i./L, which was significantly lower than dimethoate (1.17 mg a.i./L) and pirimicarb (0.89 mg a.i./L). Small, but significant, differences in sensitivity were detected in some populations against pirimicarb and dimethoate, whereas responses to alpha-cypermethrin and imidacloprid were not significantly different across all aphid populations examined in this study. For all insecticides, the field rate controlled 100% of individuals tested. The data generated will be important for future monitoring of insecticide responses of A. craccivora. Proactive management, including increased reliance on non-chemical pest management approaches and routine insecticide baseline sensitivity studies, is recommended for A. craccivora.


Asunto(s)
Áfidos , Insecticidas , Vigna , Animales , Dimetoato , Resistencia a los Insecticidas , Insecticidas/farmacología
11.
Sci Adv ; 6(20): eaba2498, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32426508

RESUMEN

Coral reefs worldwide are suffering mass mortalities from marine heat waves. With the aim of enhancing coral bleaching tolerance, we evolved 10 clonal strains of a common coral microalgal endosymbiont at elevated temperatures (31°C) for 4 years in the laboratory. All 10 heat-evolved strains had expanded their thermal tolerance in vitro following laboratory evolution. After reintroduction into coral host larvae, 3 of the 10 heat-evolved endosymbionts also increased the holobionts' bleaching tolerance. Although lower levels of secreted reactive oxygen species (ROS) accompanied thermal tolerance of the heat-evolved algae, reduced ROS secretion alone did not predict thermal tolerance in symbiosis. The more tolerant symbiosis exhibited additional higher constitutive expression of algal carbon fixation genes and coral heat tolerance genes. These findings demonstrate that coral stock with enhanced climate resilience can be developed through ex hospite laboratory evolution of their microalgal endosymbionts.


Asunto(s)
Antozoos , Dinoflagelados , Microalgas , Animales , Antozoos/genética , Antozoos/metabolismo , Blanqueamiento de los Corales , Arrecifes de Coral , Dinoflagelados/genética , Calor , Especies Reactivas de Oxígeno/metabolismo , Simbiosis/genética
12.
Bioinformatics ; 32(8): 1232-4, 2016 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-26704598

RESUMEN

MOTIVATION: RNA interference (RNAi) technology is being developed as a weapon for pest insect control. To maximize the specificity that such an approach affords we have developed a bioinformatic web tool that searches the ever-growing arthropod transcriptome databases so that pest-specific RNAi sequences can be identified. This will help technology developers finesse the design of RNAi sequences and suggests which non-target species should be assessed in the risk assessment process. AVAILABILITY AND IMPLEMENTATION: http://rnai.specifly.org CONTACT: crobin@unimelb.edu.au.


Asunto(s)
Bases de Datos Genéticas , Internet , Interferencia de ARN , Transcriptoma , Animales , Biología Computacional , Insectos , Medición de Riesgo , Especificidad de la Especie
13.
Mol Ecol ; 23(8): 1940-51, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24617944

RESUMEN

This study investigated the population genetics, demographic history and pathway of invasion of the Russian wheat aphid (RWA) from its native range in Central Asia, the Middle East and Europe to South Africa and the Americas. We screened microsatellite markers, mitochondrial DNA and endosymbiont genes in 504 RWA clones from nineteen populations worldwide. Following pathway analyses of microsatellite and endosymbiont data, we postulate that Turkey and Syria were the most likely sources of invasion to Kenya and South Africa, respectively. Furthermore, we found that one clone transferred between South Africa and the Americas was most likely responsible for the New World invasion. Finally, endosymbiont DNA was found to be a high-resolution population genetic marker, extremely useful for studies of invasion over a relatively short evolutionary history time frame. This study has provided valuable insights into the factors that may have facilitated the recent global invasion by this damaging pest.


Asunto(s)
Áfidos/genética , Genética de Población , Especies Introducidas , Animales , Buchnera/genética , ADN Bacteriano/genética , ADN Mitocondrial/genética , Femenino , Flujo Génico , Variación Genética , Haplotipos , Kenia , Repeticiones de Microsatélite , Federación de Rusia , Sudáfrica , Simbiosis , Siria , Triticum , Turquía
14.
Mol Ecol ; 21(9): 2130-44, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22417053

RESUMEN

In this study, we explore the population genetics of the Russian wheat aphid (RWA) (Diuraphis noxia), one of the world's most invasive agricultural pests, in north-western China. We have analysed the data of 10 microsatellite loci and mitochondrial sequences from 27 populations sampled over 2 years in China. The results confirm that the RWAs are holocyclic in China with high genetic diversity indicating widespread sexual reproduction. Distinct differences in microsatellite genetic diversity and distribution revealed clear geographic isolation between RWA populations in northern and southern Xinjiang, China, with gene flow interrupted across extensive desert regions. Despite frequent grain transportation from north to south in this region, little evidence for RWA translocation as a result of human agricultural activities was found. Consequently, frequent gene flow among northern populations most likely resulted from natural dispersal, potentially facilitated by wind currents. We also found evidence for the long-term existence and expansion of RWAs in China, despite local opinion that it is an exotic species only present in China since 1975. Our estimated date of RWA expansion throughout China coincides with the debut of wheat domestication and cultivation practices in western Asia in the Holocene. We conclude that western China represents the limit of the far eastern native range of this species. This study is the most comprehensive molecular genetic investigation of the RWA in its native range undertaken to date and provides valuable insights into the history of the association of this aphid with domesticated cereals and wild grasses.


Asunto(s)
Áfidos/genética , ADN Mitocondrial/genética , Repeticiones de Microsatélite , Animales , Áfidos/fisiología , China , Variación Genética , Mitocondrias/genética , Triticum
15.
Insect Mol Biol ; 19 Suppl 2: 215-28, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20482652

RESUMEN

Methylation of cytosine is one of the main epigenetic mechanisms involved in controlling gene expression. Here we show that the pea aphid (Acyrthosiphon pisum) genome possesses homologues to all the DNA methyltransferases found in vertebrates, and that 0.69% (+/-0.25%) of all cytosines are methylated. Identified methylation sites are predominantly restricted to the coding sequence of genes at CpG sites. We identify twelve methylated genes, including genes that interact with juvenile hormone, a key endocrine signal in insects. Bioinformatic prediction using CpG ratios for all predicted genes suggest that a large proportion of genes are methylated within the pea aphid.


Asunto(s)
Áfidos/genética , Áfidos/metabolismo , Metilación de ADN/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Islas de CpG , Cartilla de ADN/genética , ADN-Citosina Metilasas/genética , ADN-Citosina Metilasas/metabolismo , Epigénesis Genética , Genes de Insecto , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Hormonas Juveniles/genética , Hormonas Juveniles/metabolismo , Datos de Secuencia Molecular , Pisum sativum/parasitología , Filogenia , Homología de Secuencia de Aminoácido , Transducción de Señal/genética
16.
Bull Entomol Res ; 97(1): 41-8, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17298680

RESUMEN

Aphids are phloem-feeding insects that damage many important crops throughout the world yet, compared to plant-pathogen interactions, little is known about the mechanisms by which plants become resistant to aphids. Medicago truncatula (barrel medic) is widely considered as the pre-eminent model legume for genetic and biological research and in Australia is an important pasture species. Six cultivars of M. truncatula with varying levels of resistance to two pests of pasture and forage legumes, the bluegreen aphid Acyrthosiphon kondoi Shinji and the spotted alfalfa aphid Therioaphis trifolii f. maculata. (Buckton) are investigated. Two resistance phenotypes against T. trifolii f. maculata are described, one of which is particularly effective, killing most aphids within 24 h of infestation. Each resistance phenotype provided a similar but somewhat less effective degree of resistance to the closely-related spotted clover aphid Therioaphis trifolii (Monell). In the case of A. kondoi only one resistance phenotype was observed, which did not vary among different genetic backgrounds. None of the observed resistance against A. kondoi or T. trifolii f. maculata significantly affected the performance of green peach aphid Myzus persicae (Sulzer) or cowpea aphid Aphis craccivora Koch. The existence of multiple aphid resistance mechanisms in similar genetic backgrounds of this model plant provides a unique opportunity to characterize the fundamental basis of plant defence to these serious agricultural pests.


Asunto(s)
Áfidos/fisiología , Medicago truncatula/parasitología , Animales , Interacciones Huésped-Parásitos/fisiología , Medicago truncatula/inmunología , Fenotipo , Especificidad de la Especie
17.
Heredity (Edinb) ; 96(5): 396-402, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16570068

RESUMEN

If a novel, resistant host-plant genotype arises in the environment, insect populations utilising that host must be able to overcome that resistance in order that they can maintain their ability to feed on that host. The ability to evolve resistance to host-plant defences depends upon additive genetic variation in larval performance and adult host-choice preference. To investigate the potential of a generalist herbivore to respond to a novel resistant host, we estimated the heritability of larval performance in the noctuid moth, Helicoverpa armigera, on a resistant and a susceptible variety of the chickpea, Cicer arietinum, at two different life stages. Heritability estimates were higher for neonates than for third-instar larvae, suggesting that their ability to establish on plants could be key to the evolution of resistance in this species; however, further information regarding the nature of selection in the field would be required to confirm this prediction. There was no genetic correlation between larval performance and oviposition preference, indicating that female moths do not choose the most suitable plant for their offspring. We also found significant genotype by environment interactions for neonates (but not third-instar larvae), suggesting that the larval response to different plant genotypes is stage-specific in this species.


Asunto(s)
Cicer/parasitología , Mariposas Nocturnas/genética , Carácter Cuantitativo Heredable , Adaptación Biológica/genética , Animales , Cicer/genética , Variación Genética , Larva/genética , Larva/fisiología , Estadios del Ciclo de Vida , Oviposición/genética
18.
Eur J Endocrinol ; 150(4): 473-80, 2004 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15080776

RESUMEN

OBJECTIVE: Lanreotide Autogel is a sustained-release aqueous gel formulation supplied in a prefilled syringe, with injection volume <0.5 ml. The aim of this study was to establish the efficacy and safety of Autogel in patients with acromegaly previously treated with octreotide LAR. DESIGN: A 28-week, open, multicentre study. PATIENTS: Twelve patients with acromegaly, treated with 20 mg octreotide LAR for >4 months, with serum GH levels <10.0 mU/l. METHODS: Autogel (90 mg) was given every 28 days during weeks 0-12. At week 16 the dose was titrated based on GH levels at weeks 8 and 12. If GH levels were <2.0, 2.0-5.0, or >5.0 mU/l, Autogel was reduced to 60 mg, maintained at 90 mg, or increased to 120 mg respectively, for the next three injections. GH and IGF-I levels were reassessed at weeks 24 and 28. RESULTS: Ten patients completed the study. Five remained on 90 mg Autogel throughout the study; in two patients the dose was reduced to 60 mg from week 16; in three patients it was increased to 120 mg. Mean GH levels were: baseline, 3.0+/-1.7 mU/l; week 12, 3.5+/-1.8 mU/l; week 28, 3.3+/-1.6 mU/l (NS). Mean IGF-I levels were: baseline, 212+/-70 microg/l; week 12, 185+/-91 microg/l; week 28: 154+/-61 microg/l (P=0.027). Six patients at baseline and eight at week 28 had normalised GH and IGF-I levels. Three patients reported adverse events: musculoskeletal pain (n=2) and injection-site symptoms (n=1). CONCLUSIONS: Lanreotide Autogel is effective and well tolerated in patients with acromegaly. This study in a small group of patients with well-controlled acromegaly suggests that the majority of patients switched from 20 mg LAR to 90 mg Autogel will have equivalent or better disease control.


Asunto(s)
Acromegalia/tratamiento farmacológico , Antiinflamatorios no Esteroideos/administración & dosificación , Péptidos Cíclicos/administración & dosificación , Somatostatina/administración & dosificación , Adulto , Anciano , Antiinflamatorios no Esteroideos/efectos adversos , Antiinflamatorios no Esteroideos/sangre , Antineoplásicos Hormonales/uso terapéutico , Preparaciones de Acción Retardada , Femenino , Humanos , Inyecciones Intramusculares , Masculino , Persona de Mediana Edad , Octreótido/uso terapéutico , Péptidos Cíclicos/efectos adversos , Péptidos Cíclicos/sangre , Somatostatina/efectos adversos , Somatostatina/análogos & derivados , Somatostatina/sangre , Resultado del Tratamiento
19.
Bull Entomol Res ; 93(5): 403-11, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14641979

RESUMEN

Laboratory bioassays and field trials were used to characterize resistance to three aphid species (Myzus persicae (Sulzer), Acyrthosiphon kondoi Shinji, Aphis craccivora (Koch) in two aphid-resistant varieties (Kalya, Tanjil) and one susceptible variety (Tallerack) of Lupinus angustifolius L., and in one resistant variety (Teo) and one susceptible variety (Wodjil) of L. luteus L. Host selection tests in the glasshouse showed that alates of all three species preferred L. luteus to L. angustifolius, but provided no evidence that alates selected susceptible varieties over resistant. These results were supported by a field trial, which showed no difference in the number of colonizing A. kondoi alates collected from the resistant and susceptible lines of each lupin species, but there were significantly more late-instar nymphs and apterous adults on the susceptible lines. In laboratory host suitability experiments, there was much greater suppression of aphid growth and survival on Teo than on Kalya and Tanjil. In field trials, the numbers of aphids were generally lower on resistant compared to susceptible lines of both lupin species with one notable exception: M. persicae numbers were not lower on the resistant variety Tanjil compared to the susceptible variety Tallerack (L. angustifolius). These results suggest that the resistance mechanisms in both lupin species do not affect the selection of hosts by colonizing aphids, but rather are affecting the growth, survival and possibly reproduction of aphids after settling.


Asunto(s)
Áfidos/fisiología , Lupinus/genética , Lupinus/parasitología , Animales , Áfidos/crecimiento & desarrollo , Áfidos/inmunología , Bioensayo , Femenino , Lupinus/inmunología , Masculino , Reproducción , Australia Occidental
20.
Mol Ecol ; 12(12): 3303-11, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14629347

RESUMEN

The effects of recent colonization on the aphid parasitoid, Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae: Aphidiidae), in Western Australia were investigated. When compared with populations from the Old World, the results of a microsatellite analysis show that the insects have low allelic length and low allele frequency variation, revealing that these individuals experienced a significant founder effect. Marked genetic differentiation between populations was also revealed, which has potentially important implications for host utilization in this species when introduced to a new geographical area(s). Low genetic variation and gene flow in a founder population could limit evolutionary potential in Australia, including the ability of a population to mount a response to newly introduced hosts, such as the Russian wheat aphid, Diuraphis noxia (Mordvilko). Although the actual importance of genetic diversity in the success of biological control agents is unclear, current theory concerning the potential impact of genetic bottlenecks on additive genetic variance is discussed.


Asunto(s)
Áfidos/parasitología , Efecto Fundador , Variación Genética , Control Biológico de Vectores , Avispas/genética , Animales , Australia , Cartilla de ADN , Frecuencia de los Genes , Repeticiones de Microsatélite/genética , Densidad de Población , Avispas/fisiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA