297 research outputs found
The Plasmodium falciparum, Nima-related kinase Pfnek-4: a marker for asexual parasites committed to sexual differentiation
<b>Background</b>
Malaria parasites undergo, in the vertebrate host, a developmental switch from asexual replication to sexual differentiation leading to the formation of gametocytes, the only form able to survive in the mosquito vector. Regulation of the onset of the sexual phase remains largely unknown and represents an important gap in the understanding of the parasite's complex biology.
<b>Methods:</b>
The expression and function of the Nima-related kinase Pfnek-4 during the early sexual development of the human malaria parasite Plasmodium falciparum were investigated, using three types of transgenic Plasmodium falciparum 3D7 lines: (i) episomally expressing a Pfnek-4-GFP fusion protein under the control of its cognate pfnek-4 promoter; (ii) episomally expressing negative or positive selectable markers, yeast cytosine deaminase-uridyl phosphoribosyl transferase, or human dihydrofolate reductase, under the control of the pfnek-4 promoter; and (iii) lacking a functional pfnek-4 gene. Parasite transfectants were analysed by fluorescence microscopy and flow cytometry. In vitro growth rate and gametocyte formation were determined by Giemsa-stained blood smears.
<b>Results:</b>
The Pfnek-4-GFP protein was found to be expressed in stage II to V gametocytes and, unexpectedly, in a subset of asexual-stage parasites undergoing schizogony. Culture conditions stimulating gametocyte formation resulted in significant increase of this schizont subpopulation. Moreover, sorted asexual parasites expressing the Pfnek-4-GFP protein displayed elevated gametocyte formation when returned to in vitro culture in presence of fresh red blood cells, when compared to GFP- parasites from the same initial population. Negative selection of asexual parasites expressing pfnek-4 showed a marginal reduction in growth rate, whereas positive selection caused a marked reduction in parasitaemia, but was not sufficient to completely abolish proliferation. Pfnek-4- clones are not affected in their asexual growth and produced normal numbers of stage V gametocytes.
<b>Conclusions:</b>
The results indicate that Pfnek-4 is not strictly gametocyte-specific, and is expressed in a small subset of asexual parasites displaying high rate conversion to sexual development. Pfnek-4 is not required for erythrocytic schizogony and gametocytogenesis. This is the first study to report the use of a molecular marker for the sorting of sexually-committed schizont stage P. falciparum parasites, which opens the way to molecular characterization of this pre-differentiated subpopulation
Adherence to U.S. Physical Activity and Dietary Guidelines Among A Mexican American Cohort
Purpose: The purpose of this study is to examine adherence to risk factors for chronic diseases among Mexican Americans residing along Texas / Mexico border.
Method: Data was derived from the Cameron County Hispanic Cohort (CCHC), a prospective cohort study of over 2600 Mexican American adults aged 18 years and older living in a large and poor city along the Texas / Mexico border. Descriptive statistics and regression analysis were used to analyze the data.
Results:The sample (67.06% female) has a mean age of 48.06 ± 15.60 years, 48.81% employed, 45.66% has less than high school education, 77.57% completed the survey in Spanish, and 31.65% has some type of public or private insurance. More than 85% of the sample were either overweight (25â€BMI
Conclusions: Preventive behaviors including regular moderate to vigorous physical activity and a diet rich with fruit and vegetables are uncommon among Mexican Americans. Younger age and lower BMI were associated with meeting preventive behavior guidelines along Texas / Mexico border Mexican Americans
Metabolic Health Has Greater Impact on Diabetes than Simple Overweight/Obesity in Mexican Americans
To compare the risk for diabetes in each of 4 categories of metabolic health and BMI. Methods. Participants were drawn from the Cameron County Hispanic Cohort, a randomly selected Mexican American cohort in Texas on the US-Mexico border. Subjects were divided into 4 phenotypes according to metabolic health and BMI: metabolically healthy normal weight, metabolically healthy overweight/obese, metabolically unhealthy normal weight, and metabolically unhealthy overweight/obese. Metabolic health was defined as having less than 2 metabolic abnormalities. Overweight/obese status was assessed by BMI higher than 25 kg/m2. Diabetes was defined by the 2010 ADA definition or by being on a diabetic medication. Results. The odds ratio for diabetes risk was 2.25 in the metabolically healthy overweight/obese phenotype (95% CI 1.34, 3.79), 3.78 (1.57, 9.09) in the metabolically unhealthy normal weight phenotype, and 5.39 (3.16, 9.20) in metabolically unhealthy overweight/obese phenotype after adjusting for confounding factors compared with the metabolically healthy normal weight phenotype. Conclusions. Metabolic health had a greater effect on the increased risk for diabetes than overweight/obesity. Greater focus on metabolic health might be a more effective target for prevention and control of diabetes than emphasis on weight loss alone
Non-communicable diseases and preventive health behaviors: a comparison of Hispanics nationally and those living along the US-Mexico border
Background: Non-communicable diseases (NCDs) are rising among US Hispanics, but few studies have examined the preventive health behaviors for these NCDs among Hispanics. This study compared the preventive health behaviors of smoke-free living, physical activity, fruit and vegetable consumption, and avoidance of heavy alcohol use in Hispanics in the United States and Hispanics living along the US-Mexico border.
Methods: Two weighted data sets with information on Hispanic populations were analyzed: 1) the national Behavioral Risk Factor Surveillance Survey (n = 29,942) from 2009; and 2) the Cameron County Hispanic Cohort (n = 1,439) recruited from the US-Mexico border between 2008â2011. To compare the preventive health behaviors of the samples, within a generalized estimating equation framework, weighted univariate and multivariate logistic regression analyses were conducted controlling for age, educational attainment, employment, language, and insurance status. Statistical tests were two-sided with a significance level set at 0.05.
Results: Both samples reported low engagement in preventive behaviors. However, Hispanic males and females from the US-Mexico border were significantly less likely than the national sample to meet physical activity and fruit and vegetable consumption guidelines. Also, Hispanic males from the US-Mexico border were more likely to engage in heavy alcohol use.
Conclusion: The lack of preventive health behaviors among Hispanics living along the US-Mexico border presents a dire prospect for NCD control in the region. Multipronged approaches to address multiple behaviors should be considered
Anxiety, depression and smoking status among adults of Mexican heritage on the Texas-Mexico Border
The goal of the current analysis is to examine relationships between smoking status and anxiety and depression among adults of Mexican heritage to inform the development of culturally relevant smoking cessations efforts. Mexican heritage residents (N=1,791) of the city of Brownsville, TX, aged 18 years or older, enrolled in the Cameron County Hispanic Cohort, were selected through two stage cluster sampling of randomly selected census tracts from the first and third quartile of SES using Census 2000. Among current smokers, anxiety and depression scores were highest among women who had not completed high school (p\u3c0.05). Former smoking women, but not men, with at least a high school education and former smoking women born in the United States reported higher levels of anxiety and depression than never smoking women. Negative affective states may represent a greater barrier to smoking cessation among women than men
The Precarious Health of Young Mexican American Men in South Texas, Cameron County Hispanic Cohort, 2004â2015
Introduction
Hispanic men have higher rates of illness and death from various chronic conditions than do non-Hispanic men. We aimed to characterize the health of Mexican American men living on the USâMexico border in South Texas and elucidate indications of chronic disease in young men.
Methods
We sampled all male participants from the Cameron County Hispanic Cohort, an ongoing population-based cohort of Mexican Americans in Brownsville, Texas. We calculated descriptive statistics and stratified the sample into 3 age groups to estimate the prevalence of sociodemographic, behavioral, and clinical factors by age group and evaluated differences between age groups.
Results
Obesity prevalence was approximately 50% across all age groups (P = .83). Diabetes prevalence was high overall (26.8%), and 16.9% (95% confidence interval [CI], 10.1%â23.8%) of men younger than 35 had diabetes. More than 70% of these young men had elevated liver enzymes, and mean values of aspartate aminotransferase were significantly higher in younger men (45.0 u/L; 95% CI, 39.5â50.6 u/L) than in both older age groups. Less than 20% of young men had any form of health insurance. Current smoking was higher in young men than in men in the other groups, and the rate was higher than the national prevalence of current smoking among Hispanic men.
Conclusions
We suggest a need for obesity and diabetes prevention programs and smoking cessation programs for men in this region. Opportunities exist to expand current intervention programs and tailor them to better reach this vulnerable population of young Hispanic men. Elevated liver enzymes in men younger than 35 suggest a substantial burden of liver abnormalities, a finding that warrants further study
Nanoimprinted superlattice metallic photonic crystal as ultraselective solar absorber
A two-dimensional superlattice metallic photonic crystal (PhC) and its fabrication by nanoimprint lithography on tantalum substrates are presented. The superior tailoring capacity of the superlattice PhC geometry is used to achieve spectrally selective solar absorption optimized for high-temperature and high-efficiency solar-energy-conversion applications. The scalable fabrication route by nanoimprint lithography allows for a high-throughput and high-resolution replication of this complex pattern over large areas. Despite the high fill factor, the pattern of polygonal cavities is accurately replicated into a resist that hardens under ultraviolet radiation over an area of 10ââmmÂČ. In this way, cavities of 905 nm and 340 nm width are achieved with a period of 1 ÎŒm. After pattern transfer into tantalum via a deep reactive ion-etching process, the achieved cavities are 2.2 ÎŒm deep, separated by 85â95 nm wide ridges with vertical sidewalls. The room-temperature reflectance spectra of the fabricated samples show excellent agreement with simulated results, with a high spectral absorptance approaching blackbody absorption in the range from 300 to 1900 nm and a steep cutoff. The calculated solar absorptivity of this superlattice PhC is 96% and its thermal transfer efficiency is 82.8% at an operating temperature of 1500 K and an irradiance of 1000ââkW/mÂČ.United States. Army Research Office (W911NF-13-D-0001)United States. Department of Energy (DE-SC0001299
Preventive Health Behaviors among Hispanics: Comparing A US-Mexico Border Cohort and National Sample
Purpose: Adherence to preventive health behaviors for chronic diseases would avert 80% of all heart disease, stroke, type II diabetes, and more than 40% of cancer cases. The purpose of this study is to describe the preventive health behaviors for chronic diseases among Mexican Americans residing along U.S.-Mexico border and in the U.S.
Method: Descriptive statistics and chi-square tests were conducted on two rich data sets for Mexican Americans. The first data set (n=1439) was from the Cameron County Hispanic Cohort (CCHC), a prospective cohort study of Mexican American adults aged 18 years and older living in a large and poor city along the Texas- Mexico border. The second data set was the Hispanic Behavioral Risk Factor Surveillance System (BRFSS) for 2009, a national random sample telephone survey (n=30075).
Results:In the CCHC, the sample (67.06% female) has a mean age of 48.06 ± 15.60 years, 48.81% employed, 45.66% has less than high school education, 77.57% chose to complete the survey in Spanish, and 31.65% has some type of public or private insurance. In the Hispanic BRFSS data, there were 63.59% female with mean age of 48.34± 16.87 years, 30.47% have less than high school education, 49.02% employed, and 44.96% chose the Spanish language survey. We found more than 70% of Mexican Americans in the BRFSS data are overweight or obese, and more than 85% of the Mexican Americans along the border are overweight or obese. Less than 45% of Mexican Americans in either sample meet physical activity guidelines, and less than 25% in either sample meet fruit and vegetable daily intake guidelines. Statistically significantly fewer Mexican Americans along the US Mexico border meet either guideline compared to Mexican Americans sampled nationally (p
Conclusions: Nationally, but particularly true among Mexican Americans along the Texas-Mexico border, the majority of Mexican Americans had poor preventive health behaviors and are at risk for multiple non-communicable chronic diseases
Real-Time Geospatial analysis Identifies Gaps in Covid-19 Vaccination in a Minority Population
COVID-19 vaccination is being rapidly rolled out in the US and many other countries, and it is crucial to provide fast and accurate assessment of vaccination coverage and vaccination gaps to make strategic adjustments promoting vaccine coverage. We reported the effective use of real-time geospatial analysis to identify barriers and gaps in COVID-19 vaccination in a minority population living in South Texas on the US-Mexico Border, to inform vaccination campaign strategies. We developed 4 rank-based approaches to evaluate the vaccination gap at the census tract level, which considered both population vulnerability and vaccination priority and eligibility. We identified areas with the highest vaccination gaps using different assessment approaches. Real-time geospatial analysis to identify vaccination gaps is critical to rapidly increase vaccination uptake, and to reach herd immunity in the vulnerable and the vaccine hesitant groups. Our results assisted the City of Brownsville Public Health Department in adjusting real-time targeting of vaccination, gathering coverage assessment, and deploying services to areas identified as high vaccination gap. The analyses and responses can be adopted in other locations
Subclinical Atherosclerosis and Obesity Phenotypes Among Mexican Americans
Background Data on the influence of obesity on atherosclerosis in Hispanics are inconsistent, possibly related to varying cardiometabolic risk among obese individuals. We aimed to determine the association of obesity and cardiometabolic risk with subclinical atherosclerosis in MexicanâAmericans. Methods and Results Participants (n=503) were drawn from the Cameron County Hispanic Cohort. Metabolic health was defined as \u3c2 of the following: blood pressure â„130/85; triglyceride â„150 mg/dL; highâdensity lipoprotein cholesterol \u3c40 mg/dL (men) or \u3c50 mg/dL (women); fasting glucose â„100 mg/dL; homeostasis model assessment of insulin resistance value \u3e5.13; or highâsensitivity Câreactive protein \u3e3 mg/L. Carotid intima media thickness (cIMT) was measured. A high proportion of participants (77.8%) were metabolically unhealthy; they were more likely to be male, older, with fewer years of education, and less likely to meet daily recommendations regarding fruit and vegetable servings. Oneâthird (31.8%) had abnormal carotid ultrasound findings. After adjusting for covariates, mean cIMT varied across the obesity phenotypes (P=0.0001); there was no difference among the metabolically unhealthy regardless of whether they were obese or not. In multivariable analysis, after adjusting for covariates, cardiometabolic risk (P=0.0159), but not obesity (P=0.1446), was significantly associated with subclinical atherosclerosis. Conclusions In MexicanâAmericans, cardiometabolic risk has a greater effect on early atherosclerosis development than body mass index. Nonâobese but metabolically unhealthy participants had similar development of subclinical atherosclerosis as their obese counterparts. Interventions to maintain metabolic health among obese and nonâobese patients may be a more important goal than weight loss alone
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