Chromosome Number, Ploidy Level, and Nuclear DNA Content in 23 Species of Echeveria (Crassulaceae).

Echeveria is a polyploid genus with a wide diversity of species and morphologies. The number of species registered for Echeveria is approximately 170; many of them are native to Mexico. This genus is of special interest in cytogenetic research because it has a variety of chromosome numbers and ploidy levels. Additionally, there are no studies concerning nuclear DNA content and the extent of endopolyploidy. This work aims to investigate the cytogenetic characteristics of 23 species of Echeveria collected in 9 states of Mexico, analyzing 2n chromosome numbers, ploidy level, nuclear DNA content, and endopolyploidy levels. Chromosome numbers were obtained from root tips. DNA content was obtained from the leaf parenchyma, which was processed according to the two-step protocol with Otto solutions and propidium iodide as fluorochrome, and then analyzed by flow cytometry. From the 23 species of Echeveria analyzed, 16 species lacked previous reports of 2n chromosome numbers. The 2n chromosome numbers found and analyzed in this research for Echeveria species ranged from 24 to 270. The range of 2C nuclear DNA amounts ranged from 1.26 pg in E. catorce to 7.70 pg in E. roseiflora, while the 1C values were 616 Mbp and 753 Mbp, respectively, for the same species. However, differences in the level of endopolyploidy nuclei were found, corresponding to 4 endocycles (8C, 16C, 32C and 64C) in E. olivacea, E. catorce, E. juarezensis and E. perezcalixii. In contrast, E. longiflora presented 3 endocycles (8C, 16C and 32C) and E. roseiflora presented 2 endocycles (8C and 16C). It has been suggested that polyploidization and diploidization processes, together with the presence of endopolyploidy, allowed Echeveria species to adapt and colonize new adverse environments.

Physical mapping of 5S and 18S ribosomal DNA in three species of Agave (Asparagales, Asparagaceae).

Agave Linnaeus, 1753 is endemic of America and is considered one of the most important crops in Mexico due to its key role in the country's economy. Cytogenetic analysis was carried out in Agave tequilana Weber, 1902 'Azul', Agave cupreata Trelease et Berger, 1915 and Agave angustifolia Haworth, 1812. The analysis showed that in all species the diploid chromosome number was 2n = 60, with bimodal karyotypes composed of five pairs of large chromosomes and 25 pairs of small chromosomes. Furthermore, different karyotypical formulae as well as a secondary constriction in a large chromosome pair were found in all species. Fluorescent in situ hybridization (FISH) was used for physical mapping of 5S and 18S ribosomal DNA (rDNA). All species analyzed showed that 5S rDNA was located in both arms of a small chromosome pair, while 18S rDNA was associated with the secondary constriction of a large chromosome pair. Data of FISH analysis provides new information about the position and number of rDNA loci and helps for detection of hybrids in breeding programs as well as evolutionary studies.

[Prevalence of syncope in a sample of Mexican women residents in Mexico City]. / Prevalencia de síncope en una muestra de mujeres mexicanas residentes de la ciudad de México.

OBJECTIVE: To identify the frequency of syncope in a sample of women regular residents of Mexico City. METHODS: Two hundred and twenty one women between 18 and 88 years old with voluntary participation were included in the study. Trained interviewers through a structured questionnaire obtained syncope information. Prevalence of syncope was obtained, and it's relation with: age, time since the last syncope and frequency of syncope in their live span was registered. RESULTS: Thirty eight percent informed they had suffered syncope, of them 50% had only one syncopal episode during their lives. The others had two or more episodes. Most women had their last syncope between 19 and 50 years of age. CONCLUSIONS: The frequency of syncope was a little higher than previous studies. This is a first approximation, which must be corroborated with larger studies with well population variability representation.

Prevalencia de síncope en una muestra de mujeres mexicanas residentes de la ciudad de México / Prevalence of syncope in a sample of Mexican women residents in Mexico City

OBJECTIVE: To identify the frequency of syncope in a sample of women regular residents of Mexico City. METHODS: Two hundred and twenty one women between 18 and 88 years old with voluntary participation were included in the study. Trained interviewers through a structured questionnaire obtained syncope information. Prevalence of syncope was obtained, and it's relation with: age, time since the last syncope and frequency of syncope in their live span was registered. RESULTS: Thirty eight percent informed they had suffered syncope, of them 50% had only one syncopal episode during their lives. The others had two or more episodes. Most women had their last syncope between 19 and 50 years of age. CONCLUSIONS: The frequency of syncope was a little higher than previous studies. This is a first approximation, which must be corroborated with larger studies with well population variability representation.

Relationship between the angiotensin I-converting enzyme insertion/deletion (I/D) polymorphism and cardiovascular risk factors in healthy young Mexican women.

AIMS: Angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) polymorphism has been associated with the genetic susceptibility to several cardiovascular diseases; however, its association with cardiovascular risk factors (CRFs) in different populations needs to be clarified. The purpose of this study was to identify the CRF patterns associated with the ACE I/D polymorphism in women from different Mexican communities. METHODS: ACE I/D polymorphism was determined in two groups of healthy young women: 105 from an urban community and 59 from a semi-urban community using the polymerase chain reaction technique. Distributions of clinical and laboratory profiles among I/D genotypes were analyzed. RESULTS: Women from the semi-urban community had significantly larger waist diameter and higher diastolic blood pressure than women from the urban community (p = 0.003 and p = 0.0055). Differences in the distribution of total cholesterol (p = 0.0008), triglycerides (p = 0.0091), and low-density lipoprotein cholesterol (LDL-C) (p = 0.0272) between genotypes in each community were identified. Women with II genotype had larger values of these CRFs. Estimated risks showed that women from the urban community with the II genotype have three times more risk of having abnormal LDL-C values than women with ID genotype (p = 0.041). Estimated risks between women from semi-urban and urban community showed that urban women have 2.7 and 2.2 times more risk to have abnormal values of LDL-C and high-density lipoprotein cholesterol, respectively (p = 0.010 and p = 0.029), and that women from semi-urban community have three times more risk of having a waist diameter above 80 cm compared to the urban community (p = 0.011). CONCLUSION: The results showed that II homozygous women have higher risk of having high levels lipids and triglycerides than women with ID genotype.

[Comparison of traditional cardiovascular risk factors frequency among women of different education levels]. / Comparación de frecuencia de factores de riesgo cardiovascular tradicionales en mujeres con distinto nivel educativo.

INTRODUCTION: Ischemic heart disease is the first cause of death in the world in both genders between 30 and 40 years of age. It has been proposed that socioeconomic status could affect the prevalence of cardiovascular risk factors (CVRF), as well as cardiovascular disease incidence and mortality. The purpose of this work was to compare the frequency of CVRF in two groups of women with different educational level. RESULTS: A higher frequency of visceral obesity was identified in the women with lower educational level and hypo-HDL-C in the group of women with higher educational level. Correlation between age and modifiable CVRF was different between the studied groups. A larger proportion of women with higher educational level than those with lower educational level drank alcoholic beverages and smoked cigarettes. DISCUSSION: Frequency of identified modifiable CVRF was similar to that found in other Hispanic-American populations. The inverse relationship between CVRF and educational level, a commonly used measure of socioeconomic status, and prevalence of CVRF informed in English and American studies was not observed in this investigation; probably because social and cultural conditions could affect the educational level in a different manner. Health education programs must take into account the cultural processes of each country, city, or community, regardless of the socioeconomic status, based on social and cultural backgrounds of each group.

Comparación de frecuencia de factores de riesgo cardiovascular tradicionales en mujeres con distinto nivel educativo / Comparison of traditional cardiovascular risk factors frequency among women of different education levels

INTRODUCTION: Ischemic heart disease is the first cause of death in the world in both genders between 30 and 40 years of age. It has been proposed that socioeconomic status could affect the prevalence of cardiovascular risk factors (CVRF), as well as cardiovascular disease incidence and mortality. The purpose of this work was to compare the frequency of CVRF in two groups of women with different educational level. RESULTS: A higher frequency of visceral obesity was identified in the women with lower educational level and hypo-HDL-C in the group of women with higher educational level. Correlation between age and modifiable CVRF was different between the studied groups. A larger proportion of women with higher educational level than those with lower educational level drank alcoholic beverages and smoked cigarettes. DISCUSSION: Frequency of identified modifiable CVRF was similar to that found in other Hispanic-American populations. The inverse relationship between CVRF and educational level, a commonly used measure of socioeconomic status, and prevalence of CVRF informed in English and American studies was not observed in this investigation; probably because social and cultural conditions could affect the educational level in a different manner. Health education programs must take into account the cultural processes of each country, city, or community, regardless of the socioeconomic status, based on social and cultural backgrounds of each group.

Factores de riesgo cardiovascular en una muestra de mu- jeres jóvenes mexicanas / Cardiovascular risk factors in a sample of young Mexican women

The present work describes the prevalence of cardiovascular risk factors in young mexican women. 96 women from 18 to 40 years of age were included. All of them were measured (height, waist and hip) and weighed, blood pressure was registered, laboratory exams were taken and a questionnaire was answered. Cardiovascular risk factors prevalence was estimated and the average concentrations of lipids and glucose and systolic and diastolic blood pressure were compared by age, BMI and WHI group. Of the studied women, 51% were overweight or obese and 51% had visceral obesity with a high prevalence of lipids abnormalities (hypoalpha-lipoproteinemia and hypertrigliceridemia), which increases progressively with age. Only 5% and 4% had normal to high systolic and dyastolic blood pressures and 7% had blood glucose > 110 mg/dL. In this sample of women with similar social, demographic, economic, and cultural characteristics, a high proportion was identified with body weight problems and lipids abnormalities, a frequent finding in Latin populations with multiple etiologies and associated with different cardiovascular risk factors.

[Cardiovascular risk factors in a sample of young Mexican women]. / Factores de riesgo cardiovascular en una muestra de mu- jeres jóvenes mexicanas.

The present work describes the prevalence of cardiovascular risk factors in young mexican women. 96 women from 18 to 40 years of age were included. All of them were measured (height, waist and hip) and weighed, blood pressure was registered, laboratory exams were taken and a questionnaire was answered. Cardiovascular risk factors prevalence was estimated and the average concentrations of lipids and glucose and systolic and diastolic blood pressure were compared by age, BMI and WHI group. Of the studied women, 51% were overweight or obese and 51% had visceral obesity with a high prevalence of lipids abnormalities (hypoalpha-lipoproteinemia and hypertrigliceridemia), which increases progressively with age. Only 5% and 4% had normal to high systolic and dyastolic blood pressures and 7% had blood glucose > 110 mg/dL. In this sample of women with similar social, demographic, economic, and cultural characteristics, a high proportion was identified with body weight problems and lipids abnormalities, a frequent finding in Latin populations with multiple etiologies and associated with different cardiovascular risk factors.

Flow cytometric analysis of genome size variation in some Passiflora species.

Nuclear genome size variation was studied in eight taxa of Passiflora. Nuclear DNA content was estimated by flow cytometry of nuclei stained by propidium iodide. 2C DNA content ranged from 3.16-5.36 pg for diploids and 1.83 pg for tetraploid. Differences in nuclear genome size were observed among Passiflora species (pg): P. suberosa 1.83, P. edulis f. edulis 3.16, P. edulis f. flavicarpa (Brazil) 3.19, P. edulis f. flavicarpa (Mexico) 3.21, P. mucronata 3.40, Passiflora edmundoi 3.43, P. laurifolia 3.88, P. giberti 3.92, P. quadrangularis 5.36, the largest value being up to 192% greater than the smallest. The means of 2C DNA content were compared by the Tukey test, and the differences in genome size permitted the recognition of five taxa groups. The result was the same for the means 2C genome size (Mbp) values. The genetic parameters were studied with their respective estimators, phenotypic variance (sigma2F), genotypic variability (PhiG), and the genotypic determination index (H2). The genotypic determination index presented high magnitude estimates (greater than 99%) emphasizing the reliability of the results and demonstrating the efficiency of determining the DNA content in the species using only one leaf per plant. Passiflora species show great phenotypic variability and have different geographic distribution that might implicate in genetic diversity.