Community-Based Approaches to Reducing Health Inequities and Fostering Environmental Justice through Global Youth-Engaged Citizen Science

Growing socioeconomic and structural disparities within and between nations have created unprecedented health inequities that have been felt most keenly among the world's youth. While policy approaches can help to mitigate such inequities, they are often challenging to enact in under-resourced and marginalized communities. Community-engaged participatory action research provides an alternative or complementary means for addressing the physical and social environmental contexts that can impact health inequities. The purpose of this article is to describe the application of a particular form of technology-enabled participatory action research, called the Our Voice citizen science research model, with youth. An overview of 20 Our Voice studies occurring across five continents indicates that youth and young adults from varied backgrounds and with interests in diverse issues affecting their communities can participate successfully in multiple contributory research processes, including those representing the full scientific endeavor. These activities can, in turn, lead to changes in physical and social environments of relevance to health, wellbeing, and, at times, climate stabilization. The article ends with future directions for the advancement of this type of community-engaged citizen science among young people across the socioeconomic spectrum.

Nafcillin degradation by heterogeneous electro-Fenton process using Fe, Cu and Fe/Cu nanoparticles

Heterogeneous electro-Fenton (HEF) is as an alternative to the conventional electro-Fenton (EF) process. HEF uses a solid phase catalyst, whereas EF employs a solubilized one. This implies that in HEF, material can be recovered through a simple separation process such as filtration or magnetic separation in HEF. HEF also has the advantage of not requires a previous pH adjustment, which facilitates working in a higher pH range. In this work, Fe, Cu and Fe/Cu bimetallic nanoparticles (Fe/Cu NPs) were synthesized, characterized and used for the degradation of Nafcillin (NAF). The effect of the adsorption and the anodic oxidation (AO-H₂O₂) process was tested to assess their influence on HEF. NAF adsorption did not exceed 24% of antibiotic removal and the AO-H₂O₂ process eliminated the total NAF after 240 min of electrolysis. Through the HEF process, the antibiotic was completely removed using Fe/Cu NPs after 7.0 min of electrolysis, while these NPs, mineralization reached 41% after 240 min. In this case, NAF degradation occurs mainly due to the generation of hydroxyl radicals in the BDD electrode, and the Fenton reaction with Fe and Cu NPs. The main organic intermediates produced during the degradation of NAF by HEF were identified allowing the proposal of degradation pathway. Finally, the antibiotic was also completely eliminated from a wastewater from slaughterhouse after 15 min of treatment by HEF and using Fe/Cu bimetallic NPs.

Application of a digital PCR method for WT1 to myeloid neoplasms in CR and deep ELN WT1 molecular response (< 10 copies)

Bone marrow WT1 mRNA levels assessed by the ELN method are useful to establish prognostic correlations in myeloid malignancies treated with chemotherapy or hematopoietic stem cell transplantation (HCT). Those patients with WT1 levels below ten copies have a good outcome. However, some of these patients relapse. To further characterize this group of cases, we applied a new and sensitive digital (ddPCR) WT1 method. A consecutive series of 49 patients with treated myeloid malignancies and with an ELN WT1 quantitation of < 10 copies were included in the study. All cases (47 AML and 2 MDS) have received intensive chemotherapy or HCT. One to four micrograms of total RNA were retrotranscribed to obtain ≥ 10,000 ABL1 copies using the ELN protocol. Only those cases with a good quality cDNA were used in the ddPCR WT1 test. The ddPCR Gene Expression WT1 Assay of Bio-Rad© was used to perform the PCR amplification, and the microdroplets were quantified in the Bio-Rad's QX200 droplet reader. Eighteen patients showed a negative WT1 ddPCR assay (0 copies/μl), whereas 31 cases were positive (results ranged from 1 to 15.2 copies/μl). Survival analysis showed statistically significant differences in terms of OS between both groups, 83 ± 8% vs. 46 ± 9% (p = 0.024). A statistically significant correlation was also found between ddPCRWT1 results and CD123+ cell number detected by flow cytometry (p = 0.024). Larger series of patients tested with the current ddPCRWT1 method will solve whether it could be used to stratify patients with myeloid malignancies achieving deep WT1 molecular response (< 10 copies).

Incidence of new-onset benign anal disorders after bariatric surgery

New-onset benign anal disorders (NBADs) represent a potential complication following bariatric surgery, although their incidence in this population is not well studied. The preoperative characteristics, weight loss, bowel habits and NBADs data of 196 patients with bariatric surgery were collected by telephone interviews and medical records review and evaluated retrospectively. Ninety-nine patients had undergone gastric bypass (GBP) and 97 had a modified biliopancreatic diversion (MBPD). Fifty-nine patients were excluded. The mean follow-up of the remaining 137 patients was 87.8 months, and 51 of them (37.2%) developed NBADs. Haemorrhoids were the most common diagnosis and 27.5% of the patients that developed NBADs were treated surgically. Patients who developed NBADs had a longer follow-up time (92.5 vs. 85.1 months, P = 0.003), and those with an abnormal bowel habit (diarrhoea or constipation) had a higher percentage of NBADs (54.5 vs. 28.3%, P = 0.003). NBADs were more frequent after MBPD (52.9%) than after GBP (21.7%) (P < 0.001). Multivariate analysis found that only an abnormal bowel habit was associated with NBADs, with an odds ratio of 3.2 (95% CI: 1.5-6.9, P = 0.003). As NBADs are a common complication after bariatric surgery, further studies should be performed to find the reasons for these complications.

Phase Diagram of Fatty Acid Langmuir Monolayers from Rheological Measurements

Langmuir monolayers of fatty acids and alcohols are two-dimensional systems with a rich equilibrium phase diagram. We have explored the temperature and surface-pressure-dependent shear response of monolayers formed by fatty acids of different chain lengths and a fatty alcohol. This has been accomplished with an interfacial shear rheometer utilizing magnetic tweezers and equipped with a refined temperature control and acquisition system. Our rheological results have allowed us to draw a phase diagram from the viscoelastic properties of these 2-D systems and show new phenomena that strongly depend on temperature: the existence of a maximum in viscosity at the L2' phase, the behavior of the elastic modulus to the storage modulus ratio at the L2 phase, and the increase or decrease in viscosity at the L2-LS phase transition. In addition, we unambiguously show that the LS phase displays a counterintuitive behavior in which the loss modulus increases with temperature. We demonstrate, through isothermal surface pressure sweeps and isobaric temperature sweeps, that the exponential dependence of the loss modulus on temperature at the LS phase appears for all hydrophobic tail lengths studied and for both acid and alcohol head groups.

Magnetic microwire probes for the magnetic rod interfacial stress rheometer

The magnetic needle interfacial shear rheometer is a valuable tool for the study of the mechanical properties of thin fluid films or monolayers. However, it is difficult to differentiate the interfacial and subphase contributions to the drag on the needle. In principle, the problem can be addressed by decreasing the needle diameter, which decreases the bulk contribution while the interfacial contribution remains essentially the same. Here we show the results obtained when using a new type of needle, that of magnetic microwires with diameter approximately 10 times thinner than for commercial needles. We show that the lower inertia of the microwires calls for a new calibration procedure. We propose such a new calibration procedure based on the flow field solution around the needle introduced in refs 1 and 2. By measuring thin silicone oil films with well-controlled interfacial viscosities as well as eicosanol (C20) and pentadecanoic acid (PDA, C15) Langmuir monolayers, we show that the new calibration method works well for standard needles as well as for the microwire probes. Moreover, we show that the analysis of the force terms contributing to the force on the needle helps to ascertain whether the measurements obtained are reliable for given surface shear viscosity values. We also show that the microwire probes have at least a 10-fold-lower resolution limit, allowing one to measure interfacial viscosities as low as 10(-7) N·m/s.

Mild caloric restriction reduces blood pressure and activates endothelial AMPK-PI3K-Akt-eNOS pathway in obese Zucker rats

Genetic obesity models exhibit endothelial dysfunction associated to adenosine monophosphate-activated protein kinase (AMPK) dysregulation. This study aims to assess if mild short-term caloric restriction (CR) restores endothelial AMPK activity leading to an improvement in endothelial function. Twelve-week old Zucker lean and obese (fa/fa) male rats had access to standard chow either ad libitum (AL, n=8) or 80% of AL (CR, n=8) for two weeks. Systolic blood pressure was significantly higher in fa/fa AL rats versus lean AL animals, but was normalized by CR. Endothelium-dependent relaxation to acetylcholine (ACh, 10(-9) to 10(-4) M) was reduced in fa/fa AL compared to control lean AL rats (p<0.001), and restored by CR. The AMPK activator AICAR (10(-5) to 8·10(-3) M) elicited a lower relaxation in fa/fa AL rings that was normalized by CR (p<0.001). Inhibition of PI3K (wortmannin, 10(-7) M), Akt (triciribine, 10(-5) M), or eNOS (L-NAME, 10(-4) M) markedly reduced AICAR-induced relaxation in lean AL, but not in fa/fa AL rats. These inhibitions were restored by CR in Zucker fa/fa rings. These data show that mild short-term CR improves endothelial function and lowers blood pressure in obesity due to the activation of the AMPK-PI3K-Akt-eNOS pathway.

Phase behavior of dense colloidal binary monolayers

In this work, we study how structures develop on 2D dense binary colloidal monolayers as a function of the relative concentration of small/large particles. Translational and orientational distribution functions have been used to monitor the continuous phase transition through a detailed characterization of the global and local order. We have observed how a gradual enhancement in the number of particles of different sizes leads to a continuous vitrification process and how homogeneous binary glasses form in equimolar mixtures. Also, we have performed a simple calculation that relates the structures found to the pair dipolar potential, allowing the forecast of local structures in other arbitrary binary mixtures. Finally, we have corroborated the goodness of the binary systems as a glass-forming model by comparing the established scenario with the structural features found in partially aggregated monolayers.

Aggregation and disaggregation dynamics of sedimented and charged superparamagnetic micro-particles in water suspension

This article presents results on the aggregation and disaggregation kinetics on a 1 μm diameter charged superparamagnetic particles dispersed in water under a constant uniaxial magnetic field in experiments with salt (KCl) added to the suspension in order to observe the behaviour of the system when the electrical properties of the particles have been screened. These particles have an electric charge and are confined between two separated 100 μm thick quartz windows, and sediment near the charged bottom wall. The electrostatic interactions that take place in this experimental setup may affect the micro-structure and colloidal stability of the suspension and thus, the dynamics of aggregation and disaggregation.

Green tea reduces LDL oxidability and improves vascular function

OBJECTIVE

Several different epidemiological studies have examined the association between the consumption of tea and coronary heart disease. Some, though not all, support the view that tea or flavonoids reduce the risk of cardiovascular heart disease. The aim of this study was to determine the short-to medium-term effect of a green tea extract on vascular function and lipid peroxidation as compared with placebo.

METHODS

The study was undertaken with 14 healthy women, none of whom were receiving any medical treatment. Measurements were made of antibodies and immune complexes by ELISA, endothelial dependent vascular function by Doppler ultrasound, and the concentration of oxidized LDL by TBARS.

RESULTS

The mean diameter of the brachial artery following the post-compression hyperaemia phase rose significantly (p < 0.0001) after treatment with green tea extract. Flow-mediated brachial artery vasodilation ranged from 5.68% for the placebo phase to 11.98% after the green tea extract (p = 0.02). The consumption of green tea extract was associated with a significant 37.4% reduction in the concentration of oxidized LDL (TBARS) (p = 0.017). The levels of anti-oxidized LDL IgM antibodies fell significantly after treatment (p = 0.002).

CONCLUSION

This study found that consumption of green tea extract by women for five weeks produced modifications in vascular function and an important decrease in serum oxidizability.

Effects of hTERT on genomic instability caused by either metal or radiation or combined exposure

Genomic instability is considered to be an important component in carcinogenesis. It can be caused by low-dose exposure to agents, which appear to act through induction of stress-response pathways related to oxidative stress. These agents have been studied mostly in the radiation field but evidence is accumulating that chemicals, especially heavy metals such as Cr (VI), can also act in the same manner. Previous work showed that metal ions could initiate long-term genomic instability in human primary fibroblasts and this phenomenon was regulated by telomerase. The aim of this study was to examine the difference in clonogenic survival and cytogenetic damage after exposure to Cr (VI) and radiation both singly and in combination in normal human fibroblasts (hTERT- cells) and engineered human fibroblasts, infected with a retrovirus carrying a cDNA encoding hTERT, which rendered these cells telomerase positive and replicatively immortal (hTERT+ cells). Cr (VI) induced genomic instability in hTERT- cells but not in hTERT+ cells, whereas radiation induced genomic instability in hTERT+ cells and to a lesser extent in hTERT- cells. Combined exposure caused genomic instability in both types of cells. However, this genomic instability was more pronounced in hTERT- cells after radiation followed by Cr (VI) and more pronounced in hTERT+ cells after Cr (VI) followed by radiation. Moreover, the biological effects provoked by combined exposure of Cr (VI) and radiation also led to a synergistic action in both types of cells, compared to either Cr (VI) treatment only or radiation exposure only. This study suggests that telomerase can prevent genomic instability caused by Cr (VI), but not by radiation. Furthermore, genomic instability may be prevented by telomerase when cells are exposed to radiation and then Cr (VI) but not after exposure to Cr (VI) and then radiation.

Design and validation of a scale to assess preferences of type 2 diabetic patients towards different nutritional supplements

OBJECTIVES

To design and validate a scale to evaluate preferences of type 2 diabetic patients towards nutritional supplements (Madrid scale) and to discover those taste attributes that are more discriminating.

CONTEXT

ambulatory patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

18 controls and 106 type 2 diabetic patients received 2 of the 7 stimuli studied (6 nutritional supplements and a differential salty stimulus) and then completed both scales and a criterion question. Two weeks later, 30 diabetic patients received a retest. The psychometric properties of the Madrid scale were studied and the relative importance of each stimuli attribute was assessed.

RESULTS

Feasibility: The Madrid scale consists of 8 questions and is completed in less than five minutes; Dimensionality: A single dimension which explains 45.1% of the variance. Reliability: Cronbach's , 0.806; intraclass correlation coefficient, 0.835 (95% confidence interval: 0.653-0.922). Concurrent validity: Correlation indexes of the corrected total score with the criterion question and the Modified Wine-Tasting Scale, 0.731 (p < 0.0005) and 0.774 (p < 0.0005), respectively. The scale discriminated between subjects younger and older than 75 years and between supplements and the differential stimulus. Preferences: Glucerna SR chocolate, Glucerna SR strawberry, Glucerna SR vanilla, Diasip vanilla, Clinutren vanilla and Resource diabet vanilla.

CONCLUSION

The Madrid scale has adequate psychometric properties for its use in research and daily clinical practice.

Scaling in the aggregation dynamics of a magnetorheological fluid

We present experimental results on the aggregation dynamics of a magnetorheological fluid, namely, an aqueous suspension of micrometer-sized superparamagnetic particles, under the action of a constant uniaxial magnetic field using video microscopy and image analysis. We find a scaling behavior in several variables describing the aggregation kinetics. The data agree well with the Family-Vicsek scaling ansatz for diffusion-limited cluster-cluster aggregation. The kinetic exponents z and z' are obtained from the temporal evolution of the mean cluster size S(t) and the number of clusters N(t), respectively. The crossover exponent Delta is calculated in two ways: first, from the initial slope of the scaling function; second, from the evolution of the nonaggregated particles, n1(t). We report on results of Brownian two-dimensional dynamics simulations and compare the results with the experiments. Finally, we discuss the differences obtained between the kinetic exponents in terms of the variation in the crossover exponent and relate this behavior to the physical interpretation of the crossover exponent.

[Nutritional implications of bariatric surgery on the gastrointestinal tract]

Anatomical change in the anatomy of the gastrointestinal tract after bariatric surgery leads to modification of dietary patterns that have to be adapted to new physiological conditions, either related with the volume of intakes or the characteristics of the macro- and micronutrients to be administered. Restrictive diet after bariatric surgery (basically gastric bypass and restrictive procedures) is done at several steps. The first phase after surgery consists in the administration of clear liquids for 2-3 days, followed by completely low-fat and high-protein content (> 50-60 g/day) liquid diet for 2-4 weeks, normally by means of formula-diets. Soft or grinded diet including very soft protein-rich foods, such as egg, low-calories cheese, and lean meats such as chicken, cow, pork, or fish (red meats are not so well tolerated) is recommended 2-4 weeks after hospital discharge. Normal diet may be started within 8 weeks from surgery or even later. It is important to incorporate hyperproteic foods with each meal, such egg whites, lean meats, cheese or milk. All these indications should be done under the supervision of an expert nutrition professional to always advise the patients and adapting the diet to some special situations (nausea/vomiting, constipation, diarrhea, dumping syndrome, dehydration, food intolerances, overfeeding, etc.). The most frequent vitamin and mineral deficiencies in the different types of surgeries are reviewed, with a special focus on iron, vitamin B12, calcium, and vitamin D metabolism. It should not be forgotten that the aim of obesity surgery is making the patient loose weight and thus post-surgery diet is designed to achieve that goal although without forgetting the essential role that nutritional education has on the learning of new dietary habits contributing to maintain that weight loss over time.

Effects of hTERT on metal ion-induced genomic instability

There is currently a great interest in delayed chromosomal and other damaging effects of low-dose exposure to a variety of pollutants which appear collectively to act through induction of stress-response pathways related to oxidative stress and ageing. These have been studied mostly in the radiation field but evidence is accumulating that the mechanisms can also be triggered by chemicals, especially heavy metals. Humans are exposed to metals, including chromium (Cr) (VI) and vanadium (V) (V), from the environment, industry and surgical implants. Thus, the impact of low-dose stress responses may be larger than expected from individual toxicity projections. In this study, a short (24 h) exposure of human fibroblasts to low doses of Cr (VI) and V (V) caused both acute chromosome damage and genomic instability in the progeny of exposed cells for at least 30 days after exposure. Acutely, Cr (VI) caused chromatid breaks without aneuploidy while V (V) caused aneuploidy without chromatid breaks. The longer-term genomic instability was similar but depended on hTERT positivity. In telomerase-negative hTERT- cells, Cr (VI) and V (V) caused a long lasting and transmissible induction of dicentric chromosomes, nucleoplasmic bridges, micronuclei and aneuploidy. There was also a long term and transmissible reduction of clonogenic survival, with an increased beta-galactosidase staining and apoptosis. This instability was not present in telomerase-positive hTERT+ cells. In contrast, in hTERT+ cells the metals caused a persistent induction of tetraploidy, which was not noted in hTERT- cells. The growth and survival of both metal-exposed hTERT+ and hTERT- cells differed if they were cultured at subconfluent levels or plated out as colonies. Genomic instability is considered to be a driving force towards cancer. This study suggests that the type of genomic instability in human cells may depend critically on whether they are telomerase-positive or -negative and that their sensitivities to metals could depend on whether they are clustered or diffuse.

Effects of pork vs veal consumption on serum lipids in healthy subjects

AIMS

To analyse the influence of lean pork (P) and veal (V) consumption on the lipid profile of healthy subjects within the framework of a healthy diet comprising low levels of total fat (TF), saturated fatty acids (SFA) and cholesterol.

DESIGN

Double-crossover, randomized and controlled trial

SUBJECTS

44 healthy individuals (22 male and 22 female), recruited voluntarily from the University Complutense of Madrid. The weight and lipid profiles of these volunteers were normal and their dietary patterns were typical for people in our area.

INTERVENTIONS

The study comprised 4 phases: stabilisation phase (5 weeks), the participants followed their normal diet; second phase (6 weeks), half of the subjects, were randomised to lean pork or veal consumption, 150 g per day, for their main meal of the day; washout period (5 weeks) and final phase, which was the second phase of intervention (6 weeks). During the intervention stages, only the main meal of the day was taken in the Hospital. The rest of the subjects' diets consisted of different fortnightly menus designed in accordance with the recommendations of the Spanish Society of Arteriosclerosis (SEA).

RESULTS

After both stages of intervention had been completed, there was a mean reduction of 5.5% in low-density lipoprotein cholesterol. However, after each intervention there were no significant differences between those who had consumed P, 2.62 (0.55) mmol/L and those who had consumed V, 2.71 (0.47) mmol/L. No differences were observed in any of the other parameters between those who had consumed P and those who had consumed V.

CONCLUSIONS

Lean pork and veal produces similar effects on the lipid profiles of healthy subjects. Its consumption, as part of the saturated fat and cholesterol-controlled diet, could therefore be included in food guidelines, both for normal and therapeutic diets.

Mechanisms for dynamic crack branching in brittle elastic solids: strain field kinematics and reflected surface waves

We report on a numerical simulation study of dynamic fracture in strip-shaped plates in which we implement a fracture criterion that fully respects mode-I symmetry. The crack dynamics is studied as a function of the length of the initial notch. The cracks show accelerated straight motion until branching appears. We show that branching can be triggered by two different mechanisms: namely, the kinematics of the strain field and back-reflected surface waves traveling on the crack lip. We also propose a qualitative explanation for the kinematic branching mechanism in terms of the effects of the lattice discretization on Yoffe's stress field. The kinematic branching mechanism is understood by analyzing the disconnection times of the nodes ahead and aside of the crack tip.

Severe Hypocalcemia following Total Thyroidectomy after Biliopancreatic Diversion

Patients undergoing malabsoprtive operations for bariatric surgery are prone to disturbances of bone metabolism, but this does not commonly lead to clinical symptoms. We present a morbidly obese patient who had undergone the biliopancreatic diversion of Larrad, and presented clinical symptoms of severe hypocalcemia and tetany after total thyroidectomy. Very high doses of i.v. calcium and calcitriol and 10 days of hospitalization were required to control the symptoms and correct plasma levels. The physiological aspects that contribute to this situation are discussed.

[Implications of fiber in different pathologies]

Three decades ago, the observations of Trowell and Burkitt gave rise to the "fibre theory", in which it was contended that there was a link between the consumption of a diet rich in fibre and non-processed carbohydrates and the level of protection against many of the "first world diseases" such as constipation, diverticulosis, cancer of the colon, diabetes, obesity and cardiovascular disease. Since that time, numerous studies have been presented to analyze the relationship between fibre and disorders of the gastrointestinal tract and other processes with severe health implications. The present revision looks at the experience accumulated over this period regarding the importance of the consumption of fibre for certain phatologies. It not only deals with the epidemiological relationship existing between fibre intake and the development of diseases such as cancer of the colon or cardiovascular disorders but also reviews the interest of fibre a therapeutic agent, in view of the current information available on its different mechanism of action. Thus the possibility of using soluble fibre has taken on renewed interest for the treatment of inflammatory intestinal disease, for control of diarrhoea, in irritable bowel syndrome or no modulate the concentrations of glycaemia or cholesterol. Three is a discussion of the discrepancies found between the consumption of fibre and diverticular disease, the treatment of constipation and the association with obesity and cardiovascular disease. Despite the accumulated evidence on the consumption of fibre, there is currently no consensus as to recommendations on what type of fibre and the optimal amount that should be consumed. A high fibre intake (> 25-30 g/day) based on a variety of food sources (fruit, vegetable, legumes, cereals) is the only way to avoid many of the disorders mentioned. The consumption of a particular type of fibre (soluble or insoluble) is limited to the treatment of certain processes, because its individual relationship with many disorders is still pending determination.

Acidosis correction with a new 25 mmol/l bicarbonate/15 mmol/l lactate peritoneal dialysis solution

OBJECTIVE

The aim of this study was to evaluate the effects of a combined 25 mmol/L bicarbonate/15 mmol/L lactate-based solution (Bic/Lac), compared to a 35 mmol/L lactate solution (Lac)--the most commonly used solution for patients in southern Europe--on the venous plasma bicarbonate level in patients treated with continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

This was a randomized, parallel, controlled, open-label study, with patients studied for a period of 3 months preceded by a 1-month baseline and followed by a 1-month follow-up. Patients used the 35 mmol/L lactate solution during baseline and follow-up periods.

SETTING

Four Spanish nephrology centers.

PATIENTS

Thirty-one (20 Bic/Lac, 11 Lac) well-dialyzed (creatinine clearance > 55 L/week/1.73 m2 body surface area) CAPD patients.

INTERVENTIONS

Blood samples were taken for biochemistry tests at all visits. A physical examination was completed at baseline and month 3, and a medical update was completed after 1, 2, and 3 months, and at the follow-up visit. Adverse-event monitoring and notation of prescription changes were carried out continuously.

MAIN OUTCOME MEASURE

Effect on venous plasma bicarbonate level.

RESULTS

Venous plasma bicarbonate rose by 3.1 mmol/L (confidence intervals 1.6-4.8),from a baseline level of 23.0 mmol/L during the treatment period in those patients treated with Bic/Lac (p < 0.05 vs Lac). The number of acidotic patients (venous plasma bicarbonate < 24 mmol/L) was statistically significantly reduced at every treatment period visit in the Bic/Lac group (p < 0.05). There were no adverse findings with respect to vital signs, physical examination, or clinical symptoms, apart from one death in the control group.

CONCLUSIONS

The new Bic/Lac solution allowed better correction of acid-base status than the lactate solution.

Eating behavior in morbidly obese patients undergoing gastric surgery: differences between obese people with and without psychiatric disorders

BACKGROUND

This study analyzes eating behavior in a group of morbidly obese patients who have undergone gastric reduction surgery for weight loss, and evaluates whether the existence of psychiatric comorbidity marks significant differences in their eating behavior.

METHODS

The study group was composed of 100 morbidly obese patients (85 females, 15 males) who had received surgical treatment for weight reduction (vertical banded gastroplasty). 40 of these patients (40%) met ICD-10 criteria for the diagnosis of psychiatric disorders and were included in the "Psychiatric Obese group" (PO). The other 60 patients (60%) did not show ICD-10 diagnostic criteria and were included in the "Non-Psychiatric Obese group" (NO). Each patients completed the Binge Eating Scale (BES), the Three Factor Eating Questionnaire, the Bulimia Investigatory Test-Edinburgh (BITE), and the Eating Disorder Inventory (EDI).

RESULTS

Significant differences were found between the two groups (PO and NO) in the Binge Eating Scale (p < 0.001), Three Factor Eating Questionnaire subscale Disinhibition (p < 0.001), BITE (p < 0.001), Eating Disorder Inventory subscale Perfectionism (p < 0.002), and Global EDI (p < 0.001). Logistic regression analysis showed correlation between PO group and Global EDI (Odds Ratio OR = 1.43) and BITE (OR = 1.16). No significant gender differences were found for eating behavior, clinical diagnosis, age, percentage of weight loss, time after operation, and BMI before surgery.

CONCLUSION

Surgically treated morbidly obese patients with a psychiatric disorder (PO) have a more destructured eating pattern (with a predominance of binge eating and disinhibition) than NO.

Time scaling regimes in aggregation of magnetic dipolar particles: scattering dichroism results

We report experimental results on the aggregation kinetics in magnetorheological fluids subject to a constant uniaxial magnetic field using the technique of scattering dichroism. We show that the number of aggregated particles displays a long-time power-law dependence with exponents that correspond to two different aggregation regimes. These regimes coincide with 3D and 1D-like aggregation. We also derive the values of both time exponents for the number of aggregated particles.

[Clinical features and weight loss in patients with morbid obesity after bariatric surgery]

OBJECTIVE

To analyze the psychological status of morbidly obese patients suffering changes after surgical procedure for weight reduction.

METHODS

We analyze the weight loss in 100 morbidly obese patients (85 female, 15 male) after bariatric surgery (vertical banded gastroplasty). We correlated the percentage of weight loss with the age of these patients, initial weight (body mass index at surgery), quality of life, eating behaviour, psychopathology, personality, and marital status.

RESULTS

We have found relation between initial weight and weight loss (heavier patients lose more weight). The percentage of weight loss is associated with the Eating Behaviour (Body Dissatisfaction, Disinhibition), the Quality of Life (Positive Affect), the Psychopathology (Hostility), the Personality Traits (Narcissist), and the Marital Status (Idealistic Distortion).

CONCLUSIONS

The weight loss in morbidly obese patients after surgery is major in the more obese one. The satisfactory weight loss after surgery improve the eating behaviour, quality of life, psychological and marital status.

End processing precedes mitochondrial importation and editing of tRNAs in Leishmania tarentolae

All mitochondrial tRNAs in Leishmania tarentolae are encoded in the nuclear genome and imported into the mitochondrion from the cytosol. One imported tRNA (tRNA(Trp)) is edited by a C to U modification at the first position of the anticodon. To determine the in vivo substrates for mitochondrial tRNA importation as well as tRNA editing, we examined the subcellular localization and extent of 5'- and 3'-end maturation of tRNA(Trp)(CCA), tRNA(Ile)(UAU), tRNA(Gln)(CUG), tRNA(Lys)(UUU), and tRNA(Val)(CAC). Nuclear, cytosolic, and mitochondrial fractions were obtained with little cross-contamination, as determined by Northern analysis of specific marker RNAs. tRNA(Gln) was mainly cytosolic in localization; tRNA(Ile) and tRNA(Lys) were mainly mitochondrial; and tRNA(Trp) and tRNA(Val) were shared between the two compartments. 5'- and 3'-extended precursors of all five tRNAs were present only in the nuclear fraction, suggesting that the mature tRNAs represent the in vivo substrates for importation into the mitochondrion. Consistent with this model, T7-transcribed mature tRNA(Ile) underwent importation in vitro into isolated mitochondria more efficiently than 5'-extended precursor tRNA(Ile). 5'-Extended precursor tRNA(Trp) was found to be unedited, which is consistent with a mitochondrial localization of this editing reaction. T7-transcribed unedited tRNA(Trp) was imported in vitro more efficiently than edited tRNA(Trp), suggesting the presence of importation determinants in the anticodon.

Selective importation of RNA into isolated mitochondria from Leishmania tarentolae

All mitochondrial tRNAs in kinetoplastid protozoa are encoded in the nucleus and imported from the cytosol. Incubation of two in vitro-transcribed tRNAs, tRNA(Ile)(UAU) and tRNA(Gln)(CUG), with isolated mitochondria from Leishmania tarentolae, in the absence of any added cytosolic fraction, resulted in a protease-sensitive, ATP-dependent importation, as measured by nuclease protection. Evidence that nuclease protection represents importation was obtained by the finding that Bacillus subtilis pre-tRNA(Asp) was protected from nuclease digestion and was also cleaved by an intramitochondrial RNase P-like activity to produce the mature tRNA. The presence of a membrane potential is not required for in vitro importation. A variety of small synthetic RNAs were also found to be efficiently imported in vitro. The data suggest that there is a structural requirement for importation of RNAs greater than approximately 17 nt, and that smaller RNAs are apparently nonspecifically imported. The signals for importation of folded RNAs have not been determined, but the specificity of the process was illustrated by the higher saturation level of importation of the mainly mitochondria-localized tRNA(Ile) as compared to the level of importation of the mainly cytosol-localized tRNA(Gln). Furthermore, exchanging the D-arm between the tRNA(Ile) and the tRNA(Gln) resulted in a reversal of the in vitro importation behavior and this could also be interpreted in terms of tertiary structure specificity.

Dynamic fracture in a discrete model of a brittle elastic solid

Dynamic fracture of brittle materials is studied by means of a molecular dynamics simulation of a two-dimensional (2D) lattice of point particles. By a particular discretization of the continuum equations of elasticity, we derive the Born model in such a way that the model parameters are related to the material properties. Numerical simulations are performed, which show a branching instability, under Mode I loading, occurring at a critical crack tip speed. The analysis of the dynamical stress tensor field near the tip shows a qualitative similarity to Yoffe's stress field.

Finite resolution effects in the analysis of the scaling behavior of rough surfaces

We investigate the influence of finite spatial resolution in the analysis of the scaling behavior of rough surfaces. We analyze such an effect for two usual measurement methods: the local width and the height-height correlation function. We show that while the correlation function is insensitive to finite resolution effects for practical purposes, the local width presents correction terms to the scaling law, leading to an effective value of the local roughness exponent smaller than the theoretically expected. We also show that a functional scaling relation can only be properly formulated in terms of the height-height correlation function.

Structure and dynamics of magnetorheological fluids in rotating magnetic fields

We report on the orientation dynamics and aggregation processes of magnetorheological fluids subject to rotating magnetic fields using the technique of scattering dichroism. In the presence of stationary fields we find that the mean length of the field-induced aggregates reaches a saturation value due to finite-size effects. When a rotating field is imposed, we see the chains rotate with the magnetic field frequency (synchronous regime) but with a retarded phase angle for all the rotational frequencies applied. However, two different behaviors are found below or above a critical frequency f(c). Within the first regime (low frequency values) the size of the aggregates remains almost constant, while at high frequencies this size becomes shorter due to hydrodynamic drag. Experimental results have been reproduced by a simple model considering a torque balance on the chainlike aggregates.

C to U editing of the anticodon of imported mitochondrial tRNA(Trp) allows decoding of the UGA stop codon in Leishmania tarentolae

All mitochondrial tRNAs in kinetoplastid protists are encoded in the nucleus and imported into the organelle. The tRNA(Trp)(CCA) can decode the standard UGG tryptophan codon but can not decode the mitochondrial UGA tryptophan codon. We show that the mitochondrial tRNA(Trp) undergoes a specific C to U nucleotide modification in the first position of the anticodon, which allows decoding of mitochondrial UGA codons as tryptophan. Functional evidence for the absence of a UGA suppressor tRNA in the cytosol, using a reporter gene, was also obtained, which is consistent with a mitochondrial localization of this editing event. Leishmania cells have dealt with the problem of a lack of expression within the organelle of this non-universal tRNA by compartmentalizing an editing activity that modifies the anticodon of the imported tRNA.

[Lipid profile of the Spanish population: the DRECE (diet and risk of cardiovascular disease in Spain) study. DRECE study group]

BACKGROUND

In Spain the mortality rate due to cardiovascular disease (CVD) is relatively low compared to that of other developed countries. Until now few epidemiological studies have been performed among the global Spanish population to evaluate a relation between CVD risk factors and the lipid profile that could justify our privileged situation. For, this reason, the DRECE study was designed to know the situation at present in Spain respect to the risk of suffering from CVD in particular, the lipid profile.

POPULATION AND METHODS

This study included 4,787 subjects (2,324 males and 2,463 females) with an age ranging from 5-60 years, representative of the total Spanish population with these characteristics during the period from 1992 to 1994. Medical history was made for all participants, who also underwent a physical examination. The following parameters were determined: total cholesterol (TC), triglycerides, high-density lipoproteins cholesterol HDLc, cholesterol transported by low-density lipoproteins, LDLc (estimated by the Friedewald's formula), apolipoprotein AI and apoliprotein B (immunoturbidimetry).

RESULTS

The results obtained and expressed in mean (SD) show that, although the population has total cholesterol concentrations (190.1 [42.4] and 192.8 [44.8] mg/dl for females and males, respectively) and LDLc (113.9 [37.9] and 117.5 [38.1] mg/dl for females and males, respectively) with values as high as those found in developed countries, the HDLc concentrations (58.6 [13.2] and 51.5 [13.4] mg/dl for women and men, respectively) are also increased and this could be the reason why the mortality rate in Spain caused by CVD is lower than in other countries.

CONCLUSIONS

The finding of high HDLc levels and their antiatherogenic role could justify that, at best in part, the rate mortality in Spain is lower than in other developed countries.

The pur7 gene from the puromycin biosynthetic pur cluster of Streptomyces alboniger encodes a nudix hydrolase

Pur7 is the product of a gene from the puromycin biosynthetic pur cluster of Streptomyces alboniger. It was expressed in Escherichia coli as a recombinant protein fused to a His tag and then was highly purified through a Ni(2+) column. It showed a 3'-amino-3'-dATP pyrophosphohydrolase (nudix) activity which produced 3'-amino-3'-dAMP and pyrophosphate. This is consistent with the presence of a nudix box in its amino acid sequence. As observed with other nudix hydrolases, Pur7 has an alkaline pH optimum and a requirement for Mg(2+). Among a large variety of other nucleotides tested, only 3'-amino-3'-dTTP was a Pur7 substrate, although at lower reaction rates than 3'-amino-3'-dATP. These findings suggest that Pur7 has a high specificity for the 3' amino group at the ribofuranoside moiety of these two substrates. The K(m) and V(max) values for these dATP and dTTP derivatives were 120 microM and 17 microM/min and 3.45 mM and 12.5 microM/min, respectively. Since it is well known that 3'-amino-3'-dATP is a strong inhibitor of DNA-dependent RNA polymerase, whereas 3'-amino-3'-dAMP is not, Pur7 appears to be similar to other nudix enzymes in terms of being a housecleaning agent that permits puromycin biosynthesis to proceed through nontoxic intermediates. Finally, the identification of this activity has allowed a revision of the previously proposed puromycin biosynthetic pathway.

The Pur10 protein encoded in the gene cluster for puromycin biosynthesis of Streptomyces alboniger is an NAD-dependent ATP dehydrogenase

The pur10 gene of the puromycin (pur) cluster of Streptomyces alboniger is essential for the biosynthesis of this antibiotic. Highly purified Pur10 protein, obtained in Escherichia coli as a recombinant protein fused to a histidine tail, had an NAD-dependent ATP dehydrogenase activity. The Km and Vmax values for ATP were 0.49 mM and 14.5 nmol/min and for NAD 0.53 mM and 15.2 nmol/min, respectively. The ATP-derived product of the reaction apparently decomposed producing a triphosphorylated compound plus an adenine derivative. These and previous results suggested that Pur10 carries out the first step of the puromycin biosynthetic pathway, namely, conversion of ATP into 3'-keto-3'-deoxyATP.

[Surgery of mechanical complications of acute myocardial infarct]

Reviewed are the current surgical methods for the treatment of mechanical complications after an acute myocardial infarction, specially the subacute ventricular rupture, the most frequent complication, and in which we have the greatest experience in the world. Mechanical complications constitute the second cause of death after myocardial infarction, following pump failure. The most frequent mechanical complication is ventricular rupture, which is the cause of death in 26% of the cases of acute myocardial infarction. The setting of solid diagnostic tools, with the association of echocardiographic and hemodynamic criteria, has permitted the identification of a large number of patients with subacute ventricular rupture before death, and has allowed them to be treated surgically. The surgical techniques have evolved to more conservative methods and, nowadays, nearly all the patients can be operated on without extracorporeal circulation and using sutureless techniques. The results is greater surgical survival with satisfactory functional status at follow up. The incidence of septal and papillary muscle rupture is considerably less frequent, but of great interest. The surgical results have been improved on the basis of early diagnosis, aggressive surgical attitude, and better reparative and myocardial protection techniques.

[Parenteral nutrition of patients under intensive chemotherapy: comparative study of two lipid emulsions]

Neoplastic patients receiving intensive chemotherapy often need total parenteral nutrition (TPN), with lipid emulsions based on long-chain triglycerides (LCT) or medium-chain triglycerides (MCT). Potential benefits of MCT include easier metabolism and limited storage. Our present investigation was performed to define if there is any real clinical advantage of any of these lipid emulsions in this group of patients. Fifty-one patients receiving the LCT emulsion and sixty of them receiving the MCT-LCT one were evaluated retrospectively. TPN with 40% of non-protein kilocalories as fat was administered during a mean time of 11.5 days. No differences in total cholesterol, albumin, prealbumin, transferrin, bilirubin, alkaline phosphatase, gamma-glutamyl transpeptidase and transaminases were found between both groups, neither in nitrogen balances. In conclusion, in a group of neoplastic patients receiving intensive chemotherapy, we did not found any advantage of TPN with LCT or MCT-LCT either in nutritional laboratory parameters or in liver function.

Comparative analysis of ribonuclease P RNA using gene sequences from natural microbial populations reveals tertiary structural elements

PCR amplification of template DNAs extracted from mixed, naturally occurring microbial populations, using oligonucleotide primers complementary to highly conserved sequences, was used to obtain a large collection of diverse RNase P RNA-encoding genes. An alignment of these sequences was used in a comparative analysis of RNase P RNA secondary and tertiary structure. The new sequences confirm the secondary structure model based on sequences from cultivated organisms (with minor alterations in helices P12 and P18), providing additional support for nearly every base pair. Analysis of sequence covariation using the entire RNase P RNA data set reveals elements of tertiary structure in the RNA; the third nucleotides (underlined) of the GNRA tetraloops L14 and L18 are seen to interact with adjacent Watson-Crick base pairs in helix P8, forming A:G/C or G:A/U base triples. These experiments demonstrate one way in which the enormous diversity of natural microbial populations can be used to elucidate molecular structure through comparative analysis.

[Hashimoto toxicosis: diagnostic criteria and a 10-year follow up]

An study was carried out of the association of Basedow disease (B) and Hashimoto toxicosis (H), the response to the usual therapeutic regimens and prognostic factors for the clinical course. Seventy-one patients with the diagnosis of autoimmune hyperthyroidism were included. Sixty-one of them were prospectively followed for 8.4 +/- 2.2 years (range: 5-10 years). All patients were treated following the same criteria with antithyroid drugs and aggressive therapy (radioiodine or surgery). Two groups were differentiated: group H (62%), with titers of antimicrosomal antibodies (AMSA) > or = 1/6,400 and a positive perchlorate discharge test (PDT), and group B, with AMSA titers < 1/6,400 and negative PDT. During follow-up a three-fold number of relapses was observed in group H compared with group B, a higher frequency towards spontaneous hypothyroidism in the evolution (23% in H versus 0% in B), and higher requirements of radioiodine in H than in B. In our experience, H makes up and important percentage of autoimmune hyperthyroidism (62%) with a clinical course characterized by a higher number of relapses, higher requirements of radioiodine and a higher rate towards spontaneous hypothyroidism.

Sod and catalase inactivation by singlet oxygen and peroxyl radicals

Both superoxide dismutase and catalase are readily deactivated by singlet oxygen and by the radicals produced in the pyrolysis of 2,2'-azo-bis-(2-amidinpropano) under aerobic conditions. The rate constant for the loss of enzymatic activity induced by singlet oxygen are 3.9 x 10(7) and 2.5 x 10(7) M-1 sec-1 for SOD and catalase, respectively. The similarity between these values implies that in systems where SOD and catalase are exposed to similar singlet oxygen concentrations, it can be expected a parallel inactivation of both enzymes. The inactivation of both enzymes by the radicals produced by 2,2'-azo-bis-(2-amidinopropane) pyrolysis under aerobic conditions follows a first-order kinetics at low enzyme concentrations and a zero-order kinetics at higher concentrations. Although at low enzymatic concentrations the rate of inactivation of both enzymes is similar, this results from a compensation of effects because there are wide differences in the reactivity of both enzymes towards peroxyalkyl radicals. Catalase is considerably more reactive, but a large number of protein/radical reactive interactions are needed to inactivate one enzyme. On the other hand, the reactivity of SOD is smaller, but the average enzyme activity decreases by nearly 20% in each SOD/radical reactive interaction.

Granulocyte-macrophage colony-stimulating factor, phorbol ester, and sodium butyrate induce the CD11c integrin gene promoter activity during myeloid cell differentiation

To analyze the activity of the CD11c promoter during myeloid differentiation without the limitations of transient expression systems, we have stably transfected the myeloid U937 cell line with the pCD11C361-Luc plasmid, in which the expression of the firefly luciferase cDNA is driven by the CD11c promoter region -361/+43, previously shown to confer myeloid specificity to reporter genes. The stable transfectants (U937-C361) retained the ability to differentiate in response to phorbol-ester (PMA), sodium butyrate (SB), granulocyte-macrophage colony-stimulating factor (GM-CSF), and other differentiating agents. U937-C361 differentiation correlated with increased cellular luciferase levels, showing the inducibility of the CD11c promoter during myeloid differentiation and establishing the U937-C361 cells as a suitable system for studying the myeloid differentiation-inducing capacity of cytokines, growth, factors, and other biological response modifiers. Unexpectedly, the inducibility of the CD11c gene promoter showed distinct kinetics and magnitude on the PMA-, SB-, GM-CSF-triggered differentiation. Moreover, SB synergized with either PMA or GM-CSF in enhancing both the CD11c promoter activity and the cell surface expression of p150,95 on differentiating U937 cells. Furthermore, we showed the existence of a c-Myb-binding site at -85, the importance of the -99/-61 region in the CD11c promoter inducibility during PMA- or SB-triggered differentiation, and the dependency of the GM-CSF and PMA responsiveness of the CD11c promoter on an intact AP-1-binding site located at -60. These results, together with the lack of functional effect of mutations disrupting the Sp1-and Myb-binding sites within the proximal region of the CD11c promoter, indicate that the myeloid differentiation pathways indicated by SB and phorbol esters (or GM-CSF) activate a distinct set of transcription factors and show that the myeloid differentiation-inducibility of the CD11c gene maps to the -99/-53 proximal region of the promoter.

Monocyte activation: rapid induction of alpha 1/beta 1 (VLA-1) integrin expression by lipopolysaccharide and interferon-gamma

Monocytes play a key role in inflammation, tissue injury and remodelling and wound healing, and most monocyte effector functions are dependent on adhesive interactions. We have analyzed the changes in the pattern of beta 1 integrin expression that take place during monocyte activation and demonstrated that lipopolysaccharide (LPS) and interferon (IFN)-gamma specifically induce the expression of the alpha 1/beta 1 integrin, which was detectable on the monocyte membrane as early as 12 h after monocyte activation. The up-regulated alpha 1/beta 1 expression was not dependent on monocyte adherence to solid surfaces, and Northern blot analysis revealed that LPS and IFN-gamma induce the alpha 1 mRNA de novo. Monocyte deactivating cytokines such as interleukin (IL)-4 or IL-10, could only minimally inhibit the LPS- or IFN-gamma mediated up-regulation of alpha 1/beta 1, suggesting that cytokine release subsequent to monocyte activation does not play a major role in the integrin induction. Interestingly, the LPS-induced expression of alpha 1/beta 1 was found to be dependent on the redox state of the cell, since it was inhibited by antioxidants which also altered the morphological changes that take place during monocyte culture in vitro. The rapid induction of alpha 1 in LPS-activated monocytes suggests that alpha 1/beta 1 might be involved not only in monocyte/extracellular matrix interactions during inflammatory reactions, but also in contributing to further monocyte activation and cytokine production during septic shock syndrome.

Hematopoietic cell-type-dependent regulation of leukocyte integrin functional activity: CD11b and CD11c expression inhibits LFA-1-dependent aggregation of differentiated U937 cells

To study the influence of the cellular environment on the functional activity of leukocyte integrins and to analyze their involvement in hematopoietic cell differentiation, we have developed stable transfectants of LFA-1, Mac-1, and p150,95 (CD11a-c/CD18) leukocyte integrins in cultured cell lines whose differentiation can be induced in vitro. As on circulating leukocytes, the integrins expressed on U937 or K562 cells were expressed in a constitutively inactive state, as demonstrated by the lack of adhesion to their cellular counterreceptors or soluble ligands, the absence of CD18-dependent intercellular aggregation, and their inability to mediate adhesion to protein-coated plates. However, while leukocyte integrin adhesive functions in U937 cells were induced upon treatment with cellular agonists (e.g., PMA), their function in K562 cells could be upregulated only with activating monoclonal antibodies, demonstrating the cell-type-specific regulation of the adhesive capabilities of the three leukocyte integrins in hematopoietic cellular environment. On the other hand, the expression of either CD11b/CD18 or CD11c/CD18 in U937 myeloid cells before induction of differentiation greatly affected the adhesive phenotype of differentiating cells by abrogating the CD11a/CD18-CD54-dependent homotypic aggregation. Unlike that of mock-transfected U937 cells, differentiation of CD11b/CD18- or CD11c/CD18-transfected U937 cells led to cell adhesion and spreading on the tissue culture plates, with an almost total absence of homotypic aggregates. These results confirm the role of CD11b/CD18 and CD11c/CD18 in myeloid cell adhesion and spreading and suggest that the CD11b/- and CD11c/CD18-mediated recognition of substrate-bound ligands competes or interferes with LFA-1-dependent intercellular adhesion.