Direct introgression of untapped diversity into elite wheat lines.

The effective utilization of natural variation has become essential in addressing the challenges that climate change and population growth pose to global food security. Currently adopted protracted approaches to introgress exotic alleles into elite cultivars need substantial transformation. Here, through a strategic three-way crossing scheme among diverse exotics and the best historical elites (exotic/elite1//elite2), 2,867 pre-breeding lines were developed, genotyped and screened for multiple agronomic traits in four mega-environments. A meta-genome-wide association study, selective sweeps and haplotype-block-based analyses unveiled selection footprints in the genomes of pre-breeding lines as well as exotic-specific associations with agronomic traits. A simulation with a neutrality assumption demonstrated that many pre-breeding lines had significant exotic contributions despite substantial selection bias towards elite genomes. National breeding programmes worldwide have adopted 95 lines for germplasm enhancement, and 7 additional lines are being advanced in varietal release trials. This study presents a great leap forwards in the mobilization of GenBank variation to the breeding pipelines.

Assessment of stigma associated with tuberculosis in Mexico.

BACKGROUND: Stigma is a major barrier to health care access and impacts the quality of life for individuals affected by tuberculosis (TB). Assessing TB stigma is essential to addressing health disparities. However, no such instrument was available in Mexico at the time of our study. This study examined the adaptability of the TB and human immunodeficiency virus (HIV) stigma scales previously used in Thailand. METHODS: The original scale, developed in English, was linguistically adapted to Spanish and administered to 217 individuals affected by TB in five states in Mexico. The TB-HIV stigma subscales were designed to assess individual and community perspectives. Additional data collected included general information and socio-demographics. Assessment of psychometric properties included basic statistical tests, evaluation of Cronbach's alpha and factor analysis. RESULTS: We found no significant statistical differences associated with higher stigma scores by location, age, marital status, education and stigma scores. Factor analysis did not create any new factors. Internal consistency reliability coefficients were satisfactory (Cronbach α = 0.876-0.912). CONCLUSION: The use of the stigma scales has implications for 1) health improvements, 2) research on stigma and health disparities, and 3) TB and HIV stigma interventions. Further research is needed to examine transferability among larger and randomly selected Spanish-speaking populations.

Carotid body and cardiorespiratory alterations in intermittent hypoxia: the oxidative link.

Intermittent hypoxia, a feature of obstructive sleep apnoea, potentiates ventilatory hypoxic responses, alters heart rate variability and produces hypertension, partially owing to an enhanced carotid body responsiveness to hypoxia. Since oxidative stress is a potential mediator of both chemosensory and cardiorespiratory alterations, we hypothesised that an antioxidant treatment may prevent these alterations. Accordingly, we studied the effects of ascorbic acid (1.25 g.L(-1) drinking water) on plasma lipid peroxidation, nitrotyrosine and inducible nitric oxide synthase (iNOS) immunoreactivity in the carotid body, ventilatory and carotid chemosensory responses to acute hypoxia, heart rate variability and arterial blood pressure in male Sprague-Dawley rats exposed to 5% O(2); 12 episodes.h(-1); 8 h.day(-1) or sham condition for 21 days. Intermittent hypoxia increased plasma lipid peroxidation, nitrotyrosine and iNOS expression in the carotid body, enhanced carotid chemosensory and ventilatory hypoxic responses, modified heart rate variability and produced hypertension. Ascorbic acid prevented the increased plasma lipid peroxidation and nitrotyrosine formation within the carotid body, and the enhanced carotid chemosensory and ventilatory responses to hypoxia, as well as heart rate variability alterations and hypertension. The present results support an essential role for oxidative stress in the generation of carotid body chemosensory potentiation and systemic cardiorespiratory alterations induced by intermittent hypoxia.

Evidence for histamine as a new modulator of carotid body chemoreception.

It has been proposed that histamine is an excitatory transmitter between the glomus cells of the carotid body (CB) and the nerve endings of the petrosal ganglion (PG) neurons. The histamine biosynthetic pathway and the presence of histamine H1, H2 and H3 receptors have been reported in the CB. Thus, histamine meets some of the criteria to be regarded as a transmitter. However, there is no evidence that glomus cells contain histamine, or whether its application produces chemosensory excitation. Therefore, we studied its immunocytochemical localization on cat CB and its effects on chemosensory activity. Using perfused and superfused in vitro CB and PG preparations, we assessed the effects of histamine hydrochloride on chemosensory discharges and of histamine H1, H2 and H3 receptor blockers. We found the presence of histamine immunoreactivity in dense-core vesicles in glomus cells. In an in vitro CB preparation we performed pharmacological experiments to characterize histamine effects. The application of histamine hydrochloride (0.5-1,000 microg) to the CB produces a dose-dependent increase in the carotid sinus nerve activity. The H1 receptor blockade with pyrilamine 500 nM produces partial decrease of the histamine-induced response, whereas the H2 receptor blockade (ranitidine 100microM) fail to abolish the histamine excitatory effects. Antagonism of the H3 receptor results in an increase in carotid body chemosensory activity. On the other hand, application of histamine to the isolated PG had no effect on the carotid nerve discharge. Our results suggest that histamine is a modulator of the carotid body chemoreception through H1 and H3 receptor activation.

Cardioventilatory acclimatization induced by chronic intermittent hypoxia.

It has been proposed that chronic intermittent hypoxia (CIH) contributes to generate hypertension in patients with obstructive sleep apnea syndrome and animal models, due to an enhanced sympathetic outflow. A possible contributing mechanism to the CIH-induced hypertension is a potentiation of carotid body (CB) chemosensory responses to hypoxia, but early changes that precede the CIH-induced hypertension are not completely known. Since the variability of heart rate (HRV) has been used as an index of autonomic influences on cardiovascular system, we studied the effects of short and long-term CIH exposure on HRV in animals with or without hypertension. In cats exposed to CIH (PO(2) approximately 75 Torr, 10 times/hr during 8 hr) for 4 days, the ventilatory response to acute hypoxia was potentiated, the arterial pressure remained unchanged, but the HRV power spectrum showed a shift towards the low frequency band. Exposure of rats to CIH (PO(2) approximately 37.5 Torr, 12 times/hr during 8 hr) for 12 days enhanced the ventilatory response to acute hypoxia, but did not increase the arterial pressure. After 21 days of CIH, we found a significant increase of arterial pressure and a shift of the HRV power spectrum towards the low frequency band. Thus, our results support the idea that hypertension induced by long-term CIH was preceded by alterations in the autonomic balance of HRV, associated with an enhance CB chemoreflex sensitivity to hypoxia. Therefore, few days of CIH are enough to enhance the CB reactivity to hypoxia, which contribute to the augmented ventilatory response to hypoxia, and to the early alterations in the autonomic balance of HRV.

Understanding the HIV epidemic in the Dominican Republic: a prevention success story in the Caribbean?

OBJECTIVE: To analyze the general dynamics and trends of the HIV epidemic in the Dominican Republic (DR). METHODS: Thorough review of available HIV seroprevalence and sexual behavioral data from the DR. RESULTS: Multiple sources of data suggest that the DR's HIV epidemic has generally declined. Between the mid-1990s and about 2002, HIV-1 prevalence fell among pregnant women in the capital, Santo Domingo, particularly among young women. Declines in prevalence were also observed over the same period among sexually transmitted infection clinic patients, blood bank donors, US entry visa applicants, and female sex workers. National household surveys found 1.0% (confidence interval: 0.9% to 1.1%) adult prevalence in 2002 and 0.8% (0.6% to 0.9%) in 2007. Among largely Haitian immigrant residents of the impoverished former "sugarcane plantations," prevalence was much higher but declined from 5.0% to 3.2% between 2002 and 2007. The DR's heterogeneous epidemic includes an important men-having-sex-with-men (MSM) and bisexual component. The proportion of reported AIDS cases among men remained constant from 1989 to 2006, accounting for about two thirds of both total cumulative and year 2006 cases. Some survey and qualitative data also suggest a considerable occurrence of MSM-related risk behaviors. HIV prevalence remains relatively high in MSM, with no evidence of significant decrease. CONCLUSIONS: As in several other developing countries that have succeeded in slowing HIV transmission, HIV reductions in the DR seem mainly due to changes in sexual behavior, particularly increased condom use, especially for sex work, and partner reduction in men. Similarly favorable HIV declines and reported behavior change have occurred in some other Caribbean countries, including neighboring Haiti. However, of concern is that anal sex, both male-male and heterosexual, remains a taboo yet apparently common practice largely ignored by existing prevention campaigns. And although the DR epidemic has generally stabilized, there is a danger of complacency, and some recent data suggest that HIV prevalence is no longer declining (and may even be increasing) in some populations.

Sexual behaviors and risk factors for HIV infection among men who have sex with men in the Dominican Republic.

OBJECTIVE: To describe self-reported types of sexual identity of men who have sex with men (MSM) in the Dominican Republic, assess sociodemographics and behavioral characteristics, and measure the prevalence of HIV-1 and syphilis. DESIGN: Cross-sectional study of MSM recruited from a variety of community settings. METHODS: A total of 354 men agreed to participate after giving verbal informed consent. Information was obtained using a standardized questionnaire assessing demographics and AIDS-relevant information. Blood was obtained for HIV and syphilis testing. RESULTS: Five main sexual identity groups emerged: cross dressers, homosexuals, gigolos, bisexuals and heterosexuals. Receptive anal and oral intercourse were commonly reported by men self-identifying as cross dressers or homosexuals, whereas nearly all of the remaining three groups practiced only insertive intercourse. Sexual contact with women was also commonly reported; overall, consistent condom use was infrequent. HIV antibodies were detected in 11.0% and serologic evidence of syphilis was found in 7.3%. Factors independently associated with HIV infection included serologic evidence of syphilis, having visited at least one of four local brothels in 1975-1985, and having had receptive anal intercourse with four or more partners in the last 12 months. CONCLUSIONS: Syphilis, sexual practices and social context of sex (commercial sex), rather than sexual identity per se, were associated with HIV infection. The complex social networks of MSM in this setting, the tendency to practice either insertive or receptive sex, but not both, infrequent condom use, high rates of syphilis and the frequency of sex with women need to be taken into account for targeted HIV prevention programs to be successful.

HIV-1 and HTLV-I in sexually transmitted disease clinics in the Dominican Republic.

A cross-sectional seroprevalence study of human immunodeficiency virus type 1 (HIV-1) and human T-cell lymphotropic virus type I (HTLV-I) was undertaken among 494 attendees in two Santo Domingo sexually transmitted disease clinics in 1989. All participants were evaluated for Neisseria gonorrhoeae, Chlamydia trachomatis, syphilis, and genital ulcers. Of the 494 participants, 15 (3.0%) were positive for HIV-1 and 14 (2.8%) were positive for HTLV-I. Twelve of 371 (3.2%) men were HIV-1 seropositive: 0 of 68 homosexual/bisexual and 12 (4.0%) of 302 heterosexual men (one seronegative male could not be classified). Three (2.4%) of 123 women were HIV-1 seropositive. One (1.5%) homosexual/bisexual man, five (1.7%) heterosexual men, and eight (6.5%) women were HTLV-I seropositive. Among heterosexual men, HIV-1 was associated with multiple lifetime sex partners (O.R. = 5.9; 95% C.I. = 1.4, 23; p = 0.007). HIV-1 was associated with genital ulcer disease among women (p = 0.004). Among women, HTLV-I was associated with professional sex work (O.R. = 18; 95% C.I. = 2.1, > 100; p = 0.001). These findings suggest the need for control of sexually transmitted diseases and targeted educational programs for prevention of HIV-1 and HTLV-I among individuals with high-risk behaviors in the Dominican Republic.

El predominio heterosexual del SIDA en la República Dominicana / AIDS heterosexual predominance in the Dominican Republic

Se exponen los datos de evolución del SIDA en la República Dominicana durante el período comprendido entre 1983 y 1989. La definición del SIDA se basó en una prueba serológica positiva para el virus de la inmunodeficiencia humana (VIH) y los criterios clínicos estándares. Se notificaron al Ministerio de Salud 1 202 casos de SIDA (820 varones, 372 mujeres y 10 de sexo no verificado), con una tasa global de 17 casos por 100 000 personas. Se apreció una evolución rápida de la epidemia, habiéndose notificado 43 por ciento del total de casos en 1989. La exposición heterosexual dio cuenta de 53 por ciento (593) de los casos, con una razón varones/mujeres de 2,2:1, lo cual sugiere un país con patrón I/II según los criterios de la OMS. La prevalencia fue máxima en las zonas turísticas urbanas de Santo Domingo y Puerto Plata y sus alrededores y en los distritos de alta concentración de barracas de plantaciones de azúcar, en donde trabajan y viven trabajadores de Haití y de la República Dominicana. Se describe la distribución de casos de SIDA según las categorías de transmisión-exposición, edad, sexo, año del diagnóstico y distrito. El Programa Nacional de Vigilancia del SIDA podría mejorarse si se validaran las categorías de exposición-transmisión investigando determinados casos y se mejorara la notificación mediante la capacitación del personal de salud asistencial. Los datos de vigilancia epidemiológica contribuirán a que las actividades de salud pública futuras se dirijan a las regiones y personas expuestas a mayor riesgo

El predominio heterosexual del SIDA en la Republica Dominicana

Se exponen los datos de evolucion del SIDA en la Republica Dominicana durante el periodo comprendido entre 1983 y 1989. La definicion del SIDA se baso en una prueba serologica positiva para el virus de la inmunodeficiencia humana (VIH) y los criterios clinicos estandares. Se notificaron al Ministerio de Salud 1202 casos de SIDA (820 varones, 372 mujeres y 10 de sexo no verificado), con una tasa global de 17 casos por 100.000 personas. Se aprecio una evolucion rapida de la epidemia, habiendose notificado 43 por ciento del total de casos en 1989. Se describe la destribuicion de casos de SIDA segun las categorias de transmision - exposicion, edad, sexo, ano del diagnostico y distrito.(AU)

AIDS heterosexual predominance in the Dominican Republic.

AIDS surveillance data from the Dominican Republic are described for 1983-89. A positive serologic test for HIV was required, and standard clinical criteria were used for defining AIDS. There were 1,202 AIDS cases (820 men, 372 women, 10 of unknown gender) reported to the Ministry of Health, for a cumulative case rate of 17 per 100,000 persons. Rapid growth of the epidemic is noted, with 43% of the total cases reported in 1989. Heterosexual exposure accounts for 53% (593) of all cases, with a male-to-female ratio of 2.2:1, resembling a World Health Organization Pattern I/II country. Prevalence is highest in and surrounding the urbanized tourist areas of Santo Domingo and Puerto Plata and in districts with a high concentration of sugar plantation barracks, where laborers from Haiti and the Dominican Republic work and live. The distribution of AIDS cases is described by transmission exposure category, age, sex, year of diagnosis, and district. The National AIDS Surveillance Program can be improved by validation of exposure transmission categories through selected case investigation and by better reporting through training of health care providers. Surveillance data will assist in targeting future public health efforts to regions and persons at highest risk.

Informe de la encuesta base de conocimientos, creencias, actitudes y prácticas relevantes a las ETS y al SIDA en trabajadoras sexuales, Santo Domingo y Puerto Plata, República Dominicana, 1990 / Report of knowledge, attitudes and practice survey greats to STD and AIDS in sexual workers, Santo Domingo and Puerto Plata, Dominican Republic 1991

Primera fase del proyecto Avancemos, a traves del cual se intenta contener la transmisión del virus de inmunodeficiencia adquirida (HIV) en trabajadoras sexuales (TRSX). El estudio CCAP, fue llevado a cabo con 300 TRSX en Santo Domingo y 200 en Puerto Plata, ciudades con alta incidencia de SIDA.El diseño del cuestionario y el acopio de los datos fueron realizados por un equipo tecnico y 15 TRSX adiestrados como Mensajeros de Salud Líderes (MSL), que luego participaron como productores de módulos educativos para la acción preventiva de ETS/SIDA, como reclutadoras de Mensajeras de Salud Voluntarias (MSV) y como modeladoras de la protección sexual. Los lugares de trabajo estudiados fueron calles, cabarets, barras y casas de cita, con clientelas diferentes socioeconómicamente