Participation in pediatric epidemiologic research: the SEARCH for Diabetes in Youth Study experience

BackgroundWe evaluated the association of demographic and clinical characteristics with participation in an epidemiologic study of diabetes mellitus among youth.MethodsSEARCH for Diabetes in Youth is a multicenter study of physician-diagnosed diabetes in youth under the age of 20 comprising a surveillance and a cohort component. At each center, we enumerated all prevalent cases of diabetes in 2001 (n = 6266) and all incident cases between 2002 and 2004 (n = 3668). After confirmation of eligibility and validation, we invited each case to complete a survey and participate in a study visit. Here we evaluate how age, sex, race, and diabetes type are associated with participation in the survey and study visit.ResultsAmong prevalent cases, participation in the survey was 68% and 41% in the study visit. Among 2002 to 2004 incident cases, participation varied for the survey (76%, 81%, and 82%) and study visit (52%, 60%, and 60%). In multivariate logistic regression analyses among all incident cases, older age was associated with a lower odds of participation in the study visit (15–17 vs. < 10 years: OR 0.5, 95% CI 0.4–0.7; 18–19 vs. < 10 years: OR 0.3, 95% CI 0.2–0.5), as was having type 2 diabetes vs. type 1 diabetes (OR 0.5, 95% CI 0.4–0.7) and being of African American race vs. non-Hispanic White (OR 0.6, 95% CI 0.4–0.8). Results were very similar among prevalent cases.ConclusionsElucidating the relationship between individual characteristics and participation is essential for evaluating nonresponse bias, correcting for it, and for planning and implementing recruitment strategies.     

BNP-mediated vasodilatation for dialysis-dependent patient with acute heart failure syndrome in the emergency department

Acutely decompensated heart failure syndrome is a common emergency department presentation in patients with renal failure. B-type natriuretic peptide-mediated vasodilatation may provide a unique bridge in renal failure patients with acutely decompensated heart failure syndrome to treatment with dialysis. We evaluated the efficacy of B-type natriuretic peptide-mediated vasodilatation in acutely decompensated heart failure syndrome emergency department patients with hemodialysis dependent renal failure. This was a prospective, interventional trial. All patients received nesiritide infusion in addition to usual care. Outcome measures included hemodynamic parameters and dyspnea visual analog scale. Eight patients were enrolled, and all demonstrated significant improvement in their dyspnea visual analog scale (Delta 50.1 mm; p < .001 vs. pre-infusion) and APEX score (Delta 48.4%; p < .001 vs. pre-infusion). Three patients improved enough to be discharged from the emergency department for outpatient dialysis. In this hypothesis-generating initial trial, B-type natriuretic peptide-mediated vasodilatation with nesiritide improved symptoms in heart failure patients with hemodialysis-dependent renal failure and appears additive to standard treatment. Further trials are required to test this hypothesis.     

Endoscopic suture removal at gastrojejunal anastomosis after Roux-en-Y gastric bypass to prevent marginal ulceration

BACKGROUND: After Roux-en-Y gastric bypass (RYGB) surgery, marginal ulcers develop in 3-23% of patients. Marginal ulcers can occur secondary to the use of nonabsorbable sutures to create the gastrojejunostomy. The suture can elicit a foreign body reaction that exposes it to the gastric lumen, irritating the mucosa. Surgical removal is mandated when medical therapy fails to resolve matters. Because endoscopic removal would be less invasive than laparotomy, a technique for the endoscopic removal of the suture was devised. Presented are the results of 6 patients who underwent this procedure. METHODS: A computer search of all patients who had undergone laparoscopic RYGB was done and found 6 women who had undergone endoscopic suture removal. After a double-lumen endoscope was inserted through the mouth, a grasper was used to placed the suture under tension before transecting it with blunt-tip endoshears. The suture was then removed without difficulty. All patients were evaluated at 2 weeks and 6 months postoperatively. RESULTS: Of the patients who underwent laparoscopic RYGB between June 2003 and June 2005 and presented with epigastric pain, 6 women underwent endoscopic stitch removal. These women had a mean age of 57 years, a mean initial body mass index of 55 kg/m(2), and had undergone laparoscopic RYGB a mean of 18 months before presentation. The patients, who had experienced new-onset epigastric pain and "heartburn," underwent endoscopic examination of the stomach, which showed visible suture at the gastrojejunal anastomosis, no ulceration, and edema, and underwent suture removal. No complications developed. At 6 months of follow-up, all patients were without symptoms and had normal findings on upper endoscopy. CONCLUSION: The results of our study have shown that endoscopic suture removal is a feasible and effective means of treating epigastric pain and preventing the suture-induced marginal ulcers that can occur after RYGB.     

An atomistic picture of the regeneration process in dye sensitized solar cells

A highly efficient mechanism for the regeneration of the cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II) sensitizing dye (N3) by I^- in acetonitrile has been identified by using molecular dynamics simulation based on density functional theory. Barrier–free complex formation of the oxidized dye with both I^- and , and facile dissociation of and from the reduced dye are key steps in this process. In situ vibrational spectroscopy confirms the reversible binding of I₂ to the thiocyanate group. Additionally, simulations of the electrolyte near the interface suggest that acetonitrile is able to cover the (101) surface of anatase with a passivating layer that inhibits direct contact of the redox mediator with the oxide, and that the solvent structure specifically enhances the concentration of I^- at a distance which further favors rapid dye regeneration.     

Folate and Cobalamin Serum Levels in Healthy Children and Adolescents and Their Association with Age,Sex, BMI and Socioeconomic Status

This study proposes age- and sex-specific percentiles for serum cobalamin and folate, and analyzes the effects of sex, age, body mass index (BMI), and socioeconomic status (SES) on cobalamin and folate concentrations in healthy children and adolescents. In total, 4478 serum samples provided by healthy participants (2 months–18.0 years) in the LIFE (Leipzig Research Centre for Civilization Diseases) Child population-based cohort study between 2011 and 2015 were analyzed by electrochemiluminescence immunoassay (ECLIA). Continuous age-and sex-related percentiles (2.5th, 10th, 50th, 90th, 97.5th) were estimated, applying Cole’s LMS method. In both sexes, folate concentrations decreased continuously with age, whereas cobalamin concentration peaked between three and seven years of age and declined thereafter. Female sex was associated with higher concentrations of both vitamins in 13- to 18-year-olds and with higher folate levels in one- to five-year-olds. BMI was inversely correlated with concentrations of both vitamins, whilst SES positively affected folate but not cobalamin concentrations. To conclude, in the assessment of cobalamin and folate status, the age- and sex-dependent dynamic of the respective serum concentrations must be considered. While BMI is a determinant of both vitamin concentrations, SES is only associated with folate concentrations.     

Andrology: Incubation of spermatozoa from asthenozoospermic semen samples with pentoxifylline and 2-deoxyadenosine: variability in hyperactivation and acrosome reaction rates

We examined hyperactivation and acrosomal loss in asthenozoospermicpatients with a history of failed in-vitro fertilization (IVF).After selection by a Percoll gradient, spermatozoa were incubatedwith 3.6 mM pentoxifylline (PTX), 3.0 mM 2-deoxyadenosine (2-DXA)or both. Hyperactivation and ionophore A-23187-induced acrosomereaction were assessed immediately after sperm treatment andagain after 180 min. In all groups studied, the mean hyperactivationrates were found to be low. No significant differences werenoted between assessments immediately after treatment and 180min later, except after treatment with both PTX and 2-DXA. Themean hyperactivation rates were found not to improve as a resultof either PTX or 2-DXA, while the combination of both PTX and2-DXA revealed a significant enhancement of total hyperactivation.When individual hyperactivation rates between control and treatedsperm samples were compared, large differences in response wereobserved. Some sperm samples showed a marked increase in hyperactivationwith one treatment, while another treatment led to a decrease.Acrosome reaction rates assessed immediately after ionophoreA-23187 stimulation were found not to be significantly differentfrom those assessed 180 min later. No significant effect couldbe demonstrated for either treatment, although, here too, markedinterindividual variations were noted. It was concluded thatan unselective use of PTX, 2-DXA or both compounds together,may restore sperm function in certain of these patients, andperhaps improve fertilization in vitro, but in others it mayproduce no change or may even be detrimental to sperm function.     

Incidence of diabetes in youth in the United States

Context  Data on the incidence of diabetes mellitus (DM) among US youth according to racial/ethnic background and DM type are limited. Objective  To estimate DM incidence in youth aged younger than 20 years according to race/ethnicity and DM type. Design, Setting, and Participants  A multiethnic, population-based study (The SEARCH for Diabetes in Youth Study) of 2435 youth with newly diagnosed, nonsecondary DM in 2002 and 2003, ascertained at 10 study locations in the United States, covering a population of more than 10 million person-years. Main Outcome Measure  Incidence rates by age group, sex, race/ethnicity, and DM type were calculated per 100 000 person-years at risk. Diabetes mellitus type (type 1/type 2) was based on health care professional assignment and, in a subset, further characterized with glutamic acid decarboxylase (GAD65) autoantibody and fasting C peptide measures. Results  The incidence of DM (per 100 000 person-years) was 24.3 (95% confidence interval [CI], 23.3-25.3). Among children younger than 10 years, most had type 1 DM, regardless of race/ethnicity. The highest rates of type 1 DM were observed in non-Hispanic white youth (18.6, 28.1, and 32.9 for age groups 0-4, 5-9, and 10-14 years, respectively). Even among older youth (10 years), type 1 DM was frequent among non-Hispanic white, Hispanic, and African American adolescents. Overall, type 2 DM was still relatively infrequent, but the highest rates (17.0 to 49.4 per 100 000 person-years) were documented among 15- to 19-year-old minority groups. Conclusions  Our data document the incidence rates of type 1 DM among youth of all racial/ethnic groups, with the highest rates in non-Hispanic white youth. Overall, type 2 DM is still relatively infrequent; however, the highest rates were observed among adolescent minority populations.      

Stem cell fate analysis revisited: interpretation of individual clone dynamics in the light of a new paradigm of stem cell organization

Many experimental findings on heterogeneity, flexibility, and plasticity of tissue stem cells are currently challenging stem cell concepts that assume a cell intrinsically predefined, unidirectional differentiation program. In contrast to these classical concepts, nonhierarchical self-organizing systems provide an elegant and comprehensive alternative to explain the experimental data. Here we present the application of such a self-organizing concept to quantitatively describe the hematopoietic stem cell system. Focusing on the analysis of individual-stem-cell fates and clonal dynamics, we particularly discuss implications of the theoretical results on the interpretation of experimental findings. We demonstrate that it is possible to understand hematopoietic stem cell organization without assumptions on unidirectional developmental hierarchies, preprogrammed asymmetric division events or other assumptions implying the existence of a predetermined stem cell entity. The proposed perspective, therefore, changes the general paradigm of thinking about stem cells.