Recruitment and Retention of Latino Immigrant Families in Prevention Research

The development and testing of culturally competent interventions relies on the recruitment and retention of ethnic minority populations. Minority immigrants are a population of keen interest given their widespread growth, needs, and contributions to communities in which they settle, and particularly recent immigrants from Mexico and Central and South American countries. However, recruitment and retention strategies for entirely immigrant samples are rarely discussed in the literature. The current article describes lessons learned from two family-focused longitudinal prevention research studies of Latino immigrants in Oregon—the Adolescent Latino Acculturation Study (ALAS) and the Latino Youth and Family Empowerment Project-II (LYFE-II). Social, legal, economic, and political contexts are considered that shape Latino immigrants’ experiences in their home countries as well as in the United States. The implications of these contexts for effective recruitment and retention strategies are discussed.     

Severe isolated aortic stenosis with normal left ventricular systolic function and low transvalvular gradients: pathophysiologic and prognostic insights

BACKGROUND AND AIM OF THE STUDY: A significant proportion of patients with severe valvular aortic stenosis (AS) and preserved left ventricular (LV) systolic function have low transvalvular gradients. The study aim was to determine the mechanisms and outcome of patients with this hemodynamic profile of AS. METHODS: Among 1,679 patients who underwent transthoracic echocardiography for the evaluation of AS at the authors' institution, 215 (105 females, 110 males; mean age: 77 +/- 10 years) had isolated AS (mean aortic valve area index 0.39 +/- 0.1 cm2/m2), normal sinus rhythm and normal LV ejection fraction. The mean follow up was 23 +/- 12 months, and the end-points were mortality, aortic valve replacement (AVR), or mortality or AVR. RESULTS: Forty-seven patients had a transvalvular mean gradient (MG) <30 mmHg (MG(low)) and 168 had MG > or = 30 mmHg (MG(high)). Compared to MG(high), the MG(low) group had a higher prevalence of hypertension, lower LV end-diastolic volume index (47 +/- 9 versus 56 +/- 12 ml/m2, p <0.0001), lower LV stroke vol-ume index (37 +/- 12 versus 41 +/- 11 ml/beat, p <0.0002), a lesser severity of stenosis (aortic valve area index 0.37 +/- 0.09 versus 0.46 +/- 0.09 cm2/m2, p <0.0001) and a higher systemic vascular resistance (2163 +/- 754 versus 1879 +/- 528 dyne cm s(-5). The LV end-diastolic volume index, systemic vascular resistance and energy loss index were predictors of MG <30 mmHg (OR = 0.30, 95% CI, 0.12, 0.62; OR = 3.05, 95% CI, 1.71, 6.26; and OR = 6.76, 95% CI, 3.44,15.38, respectively). MG <30 mmHg (MGhigh) was associated with almost 50% lower referral to surgery and a two-fold increase in preoperative mortality. CONCLUSION: In severe AS with a normal LV ejection fraction, MG <30 mmHg is related to a lesser severity of stenosis, a smaller LV volume, a lower flow rate and a higher systemic vascular resistance. Compared to the MG(high) group, these patients were less frequently referred to surgery and had a higher mortality.     

Paleocene latitude of the Kohistan–Ladakh arc indicates multistage India–Eurasia collision

We report paleomagnetic data showing that an intraoceanic Trans-Tethyan subduction zone existed south of the Eurasian continent and north of the Indian subcontinent until at least Paleocene time. This system was active between 66 and 62 Ma at a paleolatitude of 8.1 ± 5.6 °N, placing it 600–2,300 km south of the contemporaneous Eurasian margin. The first ophiolite obductions onto the northern Indian margin also occurred at this time, demonstrating that collision was a multistage process involving at least two subduction systems. Collisional events began with collision of India and the Trans-Tethyan subduction zone in Late Cretaceous to Early Paleocene time, followed by the collision of India (plus Trans-Tethyan ophiolites) with Eurasia in mid-Eocene time. These data constrain the total postcollisional convergence across the India–Eurasia convergent zone to 1,350–2,150 km and limit the north–south extent of northwestern Greater India to <900 km. These results have broad implications for how collisional processes may affect plate reconfigurations, global climate, and biodiversity.

Classically, the India–Eurasia collision has been considered to be a single-stage event that occurred at 50–55 million years ago (Ma) (1, 2). However, plate reconstructions show thousands of kilometers of separation between India and Eurasia at the inferred time of collision (3, 4). Accordingly, the northern extent of Greater India was thought to have protruded up to 2,000 km relative to present-day India (5, 6) (Fig. 1). Others have suggested that the India–Eurasia collision was a multistage process that involved an east–west trending Trans-Tethyan subduction zone (TTSZ) situated south of the Eurasian margin (7–9) (Fig. 1). Jagoutz et al. (9) concluded that collision between India and the TTSZ occurred at 50–55 Ma, and the final continental collision occurred between the TTSZ and Eurasia at 40 Ma (9, 10). This model reconciles the amount of convergence between India and Eurasia with the observed shortening across the India–Eurasia collision system with the addition of the Kshiroda oceanic plate. Additionally, the presence of two subduction systems can explain the rapid India–Eurasia convergence rates (up to 16 mm a⁻¹) that existed between 135 and 50 Ma (9), as well as variations in global climate in the Cenozoic (11).Open in a separate windowFig. 1.The first panel is an overview map of tectonic structure of the Karakoram–Himalaya–Tibet orogenic system. Blue represents India, red represents Eurasia, and the Kohistan–Ladakh arc (KLA) is shown in gray. The different shades of blue highlight the deformed margin of the Indian plate that has been uplifted to form the Himalayan belt, and the zones of darker red within the Eurasian plate highlight the Eurasian continental arc batholith. Thick black lines denote the suture zones which separate Indian and Eurasian terranes. The tectonic summary panels illustrate the two conflicting collision models and their differing predictions of the location of the Kohistan–Ladakh arc. India is shown in blue, Eurasia is shown in red, and the other nearby continents are shown in gray. Active plate boundaries are shown with black lines, and recently extinct boundaries are shown with gray lines. Subduction zones are shown with triangular tick marks.While the existence of the TTSZ in the Cretaceous is not disputed, the two conflicting collision models make distinct predictions about its paleolatitude in Late Cretaceous to Paleocene time; these can be tested using paleomagnetism. In the single-stage collision model, the TTSZ amalgamated with the Eurasian margin prior to ∼80 Ma (12) at a latitude of ≥20 °N (13, 14). In contrast, in the multistage model, the TTSZ remained near the equator at ≤10 °N, significantly south of Eurasia, until collision with India (9) (Fig. 1).No undisputed paleomagnetic constraints on the location of the TTSZ are available in the central Himalaya (15–17). Westerweel et al. (18) showed that the Burma Terrane, in the eastern Himalaya, was part of the TTSZ and was located near the equator at ∼95 Ma, but they do not constrain the location of the TTSZ in the time period between 50 and 80 Ma, which is required to test the two collision hypotheses. In the western Himalaya, India and Eurasia are separated by the Bela, Khost, and Muslimbagh ophiolites and the 60,000 km² intraoceanic Kohistan Ladakh arc (19, 20) (Fig. 1). These were obducted onto India in the Late Cretaceous to Early Paleocene (19), prior to the closure of the Eocene to Oligocene Katawaz sedimentary basin (20) (Fig. 1). The Kohistan–Ladakh arc contacts the Eurasian Karakoram terrane in the north along the Shyok suture and the Indian plate in the south along the Indus suture (21) (Fig. 1). Previous paleomagnetic studies suggest that the Kohistan–Ladakh arc formed as part of the TTSZ near the equator in the early Cretaceous but provide no information on its location after 80 Ma (22–25). While pioneering, these studies lack robust age constraints, do not appropriately average paleosecular variation of the geodynamo, and do not demonstrate that the measured magnetizations have not been reset during a subsequent metamorphic episode.     

Myocardial infarction and 5,10-methylenetetrahydro-folate reductase mutation

A 40-year-old woman with previous venous thrombosis in the lower limbs had recurrent myocardial infarction in the early puerperium. The only documented risk factor was an elevated level of plasma homocysteine, associated to a heterozygotic anomaly in the enzyme responsible for its metabolism, 5,10-methylenetetrahydrofolate reductase. The case and approaches to treatment are discussed.     

Extensive in vivo self-renewal, long-term reconstitution capacity, and hematopoietic multipotency of Pax5-deficient precursor B-cell clones

Self-renewal, pluripotency, and long-term reconstitution are defining characteristics of single hematopoietic stem cells. Pax5(-/-) precursor B cells apparently possess similar characteristics. Here, using serial transplantations, with in vitro recloning and growth of the bone marrow-homed donor cells occurring after all transplantations, we analyzed the extent of self-renewal and hematopoietic multipotency of Pax5(-/-) precursor B-cell clones. Moreover, telomere length and telomerase activity in these clones was analyzed at various time points. Thus far, 5 successive transplantations have been performed. Clones transplanted for the fifth time, which have proliferated for more than 150 cell divisions in vitro, still repopulate the bone marrow with precursor B cells and reconstitute these recipients with lymphoid and myeloid cells. During this extensive proliferation, Pax5(-/-) precursor B cells shorten their telomeres at 70 to 90 base pairs per division. Their telomerase activity remains at 3% of that of HEK293 cancer cells during all serial in vivo transplantations/in vitro expansions. Together, these data show that Pax5(-/-) precursor B-cell clones possess extensive in vivo self-renewal capacity, long-term reconstitution capacity, and hematopoietic multipotency, with their telomeres shortening at the normal rate.     

Simultaneous double-isotope autoradiographic measurement of local cerebral glucose metabolic rate and acid-base status in rat brain

We developed a double-isotope autoradiographic method for the simultaneous measurement of the local cerebral metabolic rate for glucose (1CMRG) and index of regional acid-base status (rABI) in single brain slices using [2-¹⁴C]deoxy-D-glucose (DG) and 5,5-dimethyl-[2-¹⁴C]oxazolidine-2,4, dione (DMO). After iv isotope administration, paper chromatography separates plasma DMO from DG activity using a methanol-methylene chloride solvent system. Initial tissue autoradiograms depict regional DMO plus DG and DG metabolite distribution. After 14 days in a well-ventilated hood, 97.5 ±0.5% of all DMO is lost from tissue sections by sublimation, and a second autoradiogram depicts DG plus DG metabolite distribution. Retention of brain lipids does not alter beta-particle self-absorption, avoiding problems associated with isotope extraction with solvents. Autoradiograms are digitized and converted to isotope-content images. The second autoradiogram is used for lCMRG computation. After subtracting the second regional isotope-content value from the first, the DMO content is obtained and used to compute rABI. Application of this method to normal animals yields expected values for lCMRG and rABI. This method is amenable to whole-slice digitization and creation of functional images of lCMRG and ABI followed by pixel-by-pixel correlations of the two variables, making this a potentially valuable tool for the investigation of the relationships between glucose metabolism and brain acid-base balance.     

Social reasoning in Tourette syndrome

Introduction. Tourette syndrome (TS) is thought to be associated with striatal dysfunction. Changes within frontostriatal pathways in TS could lead to changes in abilities reliant on the frontal cortex. Such abilities include executive functions and aspects of social reasoning.

Methods. This study aimed to investigate executive functioning and Theory of Mind (ToM; the ability to reason about mental states, e.g., beliefs and emotions), in 18 patients with TS and 20 controls. A range of tasks involving ToM were used. These required participants to make judgements about mental states based on pictures of whole faces or the eyes alone, reason about humour in cartoons that featured sarcasm, irony or “slapstick” style humour, and make economic decisions. The executive measures assessed inhibition and verbal fluency.

Results. Patients with TS exhibited significantly poorer performance than controls on all four tasks involving ToM, even when patients with comorbid obsessive-compulsive disorder were excluded. These difficulties were despite no inhibitory deficits. Patients with TS exhibited impairment on the verbal fluency task but their performance on executive and ToM tasks was not related.

Conclusions. We propose that TS is associated with changes in ToM. The observed deficits could reflect dysfunction in frontostriatal pathways involving ventromedial prefrontal cortex.