Discovering linear causal model from incomplete data

One common drawback in algorithms for learning Linear Causal Models is that they can not deal with incomplete data set. This is unfortunate since many real problems involve missing data or even hidden variable. In this paper, based on multiple imputation, we propose a three-step process to learn linear causal models from incomplete data set. Experimental results indicate that this algorithm is better than the single imputation method (EM algorithm) and the simple list deletion method, and for lower missing rate, this algorithm can even find models better than the results from the greedy learning algorithm MLGS working in a complete data set. In addition, the method is amenable to parallel or distributed processing, which is an important characteristic for data mining in large data sets.

Regional specificity of exercise and calcium during skeletal growth in girls: a randomized controlled trial

Combining exercise with calcium supplementation may produce additive or multiplicative effects at loaded sites; thus, we conducted a single blind, prospective, randomized controlled study in pre- and early-pubertal girls to test the following hypotheses. (1) At the loaded sites, exercise and calcium will produce greater benefits than exercise or calcium alone. (2) At non-loaded sites, exercise will have no benefit, whereas calcium with or without exercise will increase bone mass over that in exercise alone or no intervention. Sixty-six girls aged 8.8 ± 0.1 years were randomly assigned to one of four study groups: moderate-impact exercise with or without calcium or low-impact exercise with or without calcium. All participants exercised for 20 minutes, three times a week and received Ca-fortified (434 ± 19 mg/day) or non-fortified foods for 8.5 months. Analysis of covariance (ANCOVA) was used to determine interaction and main effects for exercise and calcium on bone mass after adjusting for baseline bone mineral content and growth in limb lengths. An exercise-calcium interaction was detected at the femur (7.1%, p < 0.05). In contrast, there was no exercise-calcium interaction detected at the tibia-fibula; however, there was a main effect of exercise: bone mineral content increased 3% more in the exercise than non-exercise groups (p < 0.05). Bone mineral content increased 2-4% more in the calcium-supplemented groups than the non-supplemented groups at the humerus (12.0% vs. 9.8%, respectively, p < 0.09) and radius-ulna (12.6% vs. 8.6%, respectively, p < 0.01). In conclusion, greater gains in bone mass at loaded sites may be achieved when short bouts of moderate exercise are combined with increased dietary calcium, the former conferring region-specific effects and the latter producing generalized effects.

The effect of calcium supplementation on bone density in premenarcheal females: a co-twin approach

The age and developmental stage at which calcium supplementation produces the greatest bone effects remain controversial. We tested the hypothesis that calcium supplementation may improve bone accrual in premenarcheal females. Fifty-one pairs of premenarcheal female twins (27 monozygotic and 24 dizygotic; mean ± SD age, 10.3 ± 1.5 yr) participated in a randomized, single-blind, placebo-controlled trial with one twin of each pair receiving a 1200-mg calcium carbonate (Caltrate) supplement. Areal bone mineral density (aBMD) was measured at baseline and 6, 12, 18 and 24 months. There were no within-pair differences in height, weight, or calcium intake at baseline. Calcium supplementation was associated (P < 0.05) with increased aBMD compared with placebo, adjusted for age, height, and weight at the following time points from baseline: total hip, 6 months (1.9%), 12 months (1.6%), and 18 months (2.4%); lumbar spine, 12 months (1.0%); femoral neck, 6 months (1.9%). Adjusted total body bone mineral content was higher in the calcium group at 6 months (2.0%), 12 months (2.5%), 18 months (4.6%), and 24 months (3.7%), respectively (all P < 0.001). Calcium supplementation was effective in increasing aBMD at regional sites over the first 12–18 months, but these gains were not maintained to 24 months.

Cholesterol-lowering effects of plant sterol esters and non-esterified stanols in margarine, butter and low-fat foods

Objectives: To determine the efficacy on plasma cholesterol-lowering of plant sterol esters or non-esterified stanols eaten within low-fat foods as well as margarine.
Design: Randomised, controlled, single-blind study with sterol esters and non-esterified plant stanols provided in breakfast cereal, bread and spreads. Study 1 comprised 12 weeks during which sterol esters (2.4 g) and stanol (2.4 g) -containing foods were eaten during 4 week test periods of cross-over design following a 4 week control food period. In Study 2, in a random order cross-over design, a 50% dairy fat spread with or without 2.4 g sterol esters daily was tested.
Subjects: Hypercholesterolaemic subjects; 22 in study 1 and 15 in study 2.
Main outcome measures: Plasma lipids, plasma sterols, plasma carotenoids and tocopherols.
Results: Study 1¾median LDL cholesterol was reduced by the sterol esters (-13.6%; P<0.001 by ANOVA on ranks; P<0.05 by pairwise comparison) and by stanols (-8.3%; P=0.003, ANOVA and <0.05 pairwise comparison). With sterol esters plasma plant sterol levels rose (35% for sitosterol, 51% for campesterol; P<0.001); plasma lathosterol rose 20% (P=0.03), indicating compensatory increased cholesterol synthesis. With stanols, plasma sitosterol fell 22% (P=0.004), indicating less cholesterol absorption. None of the four carotenoids measured in plasma changed significantly. In study 2, median LDL cholesterol rose 6.5% with dairy spread and fell 12.2% with the sitosterol ester fortified spread (P=0.03 ANOVA and <5% pairwise comparison).
Conclusion: 1. Plant sterol esters and non-esterified stanols, two-thirds of which were incorporated into low-fat foods, contributed effectively to LDL cholesterol lowering, extending the range of potential foods. 2. The LDL cholesterol-raising effect of butter fat could be countered by including sterol esters. 3. Plasma carotenoids and tocopherols were not reduced in this study.

Oat beta-glucan lowers total and LDL-cholesterol

Several soluble polysaccharides have been shown to have cholesterol-lowering properties and to have a role in prevention of heart disease. Major sources of one such polysaccharide (beta-glucan) are oats and barley. The aim of this study was to examine the effects on plasma lipid concentrations when beta-glucan derived from a fractionated oat preparation was consumed by people with elevated plasma lipids. A single-blind, crossover design compared plasma cholesterol, triglycerides, high density lipoproteins and low density lipoproteins (LDLs) in 14 people; in the order of low, high and low beta-glucan supplemented diets, each of three weeks duration. For the high beta-glucan diet, an average intake of 7 g per day was consumed from cereal, muffins and bread. The background diet remained relatively constant over the three test periods. Differences during the interventions were calculated by one-way repeated measures analysis of variance. Where treatments were found to be significantly different, pairwise multiple comparison procedures (Tukey Test) were carried out between the high beta-glucan and each of the low beta-glucan phases and there was a highly significant difference between treatments for plasma cholesterol (P = 0.009) and for LDL-cholesterol concentrations (P < 0.001). The differences in plasma cholesterol (6.42 +/- 0.7, 6.14 +/- 0.53, 6.44 +/- 0.67 mmol/L) and LDL-cholesterol (4.59 +/- 0.59, 4.17 +/0.58, 4.52 +/- 0.65 mmol/L) between high beta-glucan and each of the low beta-glucan treatments were significant (P < 0.05). The effect on LDLs (9% lower) is among the highest reported. The results of this study confirm that beneficial reductions in plasma cholesterol and LDL-cholesterol concentrations can be obtained with beta-glucan incorporated into a variety of foods.

Manipulation of dietary short chain carbohydrates alters the pattern of gas production and genesis of symptoms in irritable bowel syndrome

Background and Aim:  Reduction of short-chain poorly absorbed carbohydrates (FODMAPs) in the diet reduces symptoms of irritable bowel syndrome (IBS). In the present study, we aimed to compare the patterns of breath hydrogen and methane and symptoms produced in response to diets that differed only in FODMAP content.
Methods:  Fifteen healthy subjects and 15 with IBS (Rome III criteria) undertook a single-blind, crossover intervention trial involving consuming provided diets that were either low (9 g/day) or high (50 g/day) in FODMAPs for 2 days. Food and gastrointestinal symptom diaries were kept and breath samples collected hourly over 14 h on day 2 of each diet.
Results:  Higher levels of breath hydrogen were produced over the entire day with the high FODMAP diet for healthy volunteers (181 ± 77 ppm.14 h vs 43 ± 18; mean ± SD P < 0.0001) and patients with IBS (242 ± 79 vs 62 ± 23; P < 0.0001), who had higher levels during each dietary period than the controls (P < 0.05). Breath methane, produced by 10 subjects within each group, was reduced with the high FODMAP intake in healthy subjects (47 ± 29 vs 109 ± 77; P = 0.043), but was not different in patients with IBS (126 ± 153 vs 86 ± 72). Gastrointestinal symptoms and lethargy were significantly induced by the high FODMAP diet in patients with IBS, while only increased flatus production was reported by healthy volunteers.
Conclusions:  Dietary FODMAPs induce prolonged hydrogen production in the intestine that is greater in IBS, influence the amount of methane produced, and induce gastrointestinal and systemic symptoms experienced by patients with IBS. The results offer mechanisms underlying the efficacy of the low FODMAP diet in IBS.

Qualitative methods in early-phase drug trials : data and methods from a trial of N-acetylcysteine in schizophrenia

Objective: The pharmacokinetic profile of a drug often gives little indication of its potential therapeutic application, with many therapeutic uses of drugs being discovered serendipitously while being studied for different indications. As hypothesis-driven, quantitative research methodology is exclusively used in early-phase trials, unexpected but important phenomena may escape detection. In this context, this study aimed to examine the potential for integrating qualitative research methods with quantitative methods in early-phase drug trials. To our knowledge, this mixed methodology has not previously been applied to blinded psychopharmacologic trials.

Method: We undertook qualitative data analysis of clinical observations on the dataset of a randomized, double-blind, placebo-controlled trial of N-acetylcysteine (NAC) in patients with DSM-IV-TR–diagnosed schizophrenia (N = 140). Textual data on all participants, deliberately collected for this purpose, were coded using NVivo 2, and emergent themes were analyzed in a blinded manner in the NAC and placebo groups. The trial was conducted from November 2002 to July 2005.

Results: The principal findings of the published trial could be replicated using a qualitative methodology. In addition, significant differences between NAC- and placebo-treated participants emerged for positive and affective symptoms, which had not been captured by the rating scales utilized in the quantitative trial. Qualitative data in this study subsequently led to a positive trial of NAC in bipolar disorder.

Conclusions: The use of qualitative methods may yield broader data and has the potential to complement traditional quantitative methods and detect unexpected efficacy and safety signals, thereby maximizing the findings of early-phase clinical trial research.

A prospective study of the effect of education on non-compliant behaviour in contact lens wear

The contact lens practitioner and patient present a specific case for the study of non-compliance in areas such as hygiene, solution use, appointment attendance and wearing times. Education is one of the factors thought to influence compliance among patients in general health care situations and contact lens practitioners are encouraged to educate patients in the care and maintenance of contact lenses. A prospective, randomized, controlled and double masked study was performed to assess the effect of a‘compliance enhancement strategy’ on levels of compliance among contact lens wearers over twelve months. Eighty experienced contact lens patients were randomly allocated to two experimental groups. A standard level of contact lens instruction was applied to the first group and in addition the compliance enhancement strategy was applied to patients assigned to the second group. The strategy consisted of extra education for patients using a video, booklets, posters, a checklist and a health care contract. Patients were given free supplies of RelMu multipurpose solution and Medalist 38 soft contact lenses IBausch and Lomb, Rochester. New York). Compliance levels were assessed at a twelve month aftercare appointment by demonstration and questionnaire. The results indicate that the compliance enhancement strategy had little significant effect on the compliance levels of the patients to whom it was applied. The population of contact lens wearers were generally very compliant and the contact lenses and care regimen were clinically successful. The possibility that the assessment of non–compliance was not adequately sensitive to highlight small differences in non-compliant, behaviour is discussed. The standard level of eduction applied to this sample of contact lens patients was adequate to ensure generally high levels of compliance with the simple care and maintenance regimen recommended.

Additional Saturday rehabilitation improves functional independence and quality of life and reduces length of stay: a randomised controlled trial

Background

Many inpatients receive little or no rehabilitation on weekends. Our aim was to determine what effect providing additional Saturday rehabilitation during inpatient rehabilitation had on functional independence, quality of life and length of stay compared to 5 days per week of rehabilitation.

This was a multicenter, single-blind (assessors) randomized controlled trial with concealed allocation and 12-month follow-up conducted in two publically funded metropolitan inpatient rehabilitation facilities in Melbourne, Australia. Patients were eligible if they were adults (aged ≥18 years) admitted for rehabilitation for any orthopedic, neurological or other disabling conditions excluding those admitted for slow stream rehabilitation/geriatric evaluation and management. Participants were randomly allocated to usual care Monday to Friday rehabilitation (control) or to Monday to Saturday rehabilitation (intervention). The additional Saturday rehabilitation comprised physiotherapy and occupational therapy. The primary outcomes were functional independence (functional independence measure (FIM); measured on an 18 to 126 point scale), health-related quality of life (EQ-5D utility index; measured on a 0 to 1 scale, and EQ-5D visual analog scale; measured on a 0 to 100 scale), and patient length of stay. Outcome measures were assessed on admission, discharge (primary endpoint), and at 6 and 12 months post discharge.

We randomly assigned 996 adults (mean (SD) age 74 (13) years) to Monday to Saturday rehabilitation (n = 496) or usual care Monday to Friday rehabilitation (n = 500). Relative to admission scores, intervention group participants had higher functional independence (mean difference (MD) 2.3, 95% confidence interval (CI) 0.5 to 4.1, P = 0.01) and health-related quality of life (MD 0.04, 95% CI 0.01 to 0.07, P = 0.009) on discharge and may have had a shorter length of stay by 2 days (95% CI 0 to 4, P = 0.1) when compared to control group participants. Intervention group participants were 17% more likely to have achieved a clinically significant change in functional independence of 22 FIM points or more (risk ratio (RR) 1.17, 95% CI 1.03 to 1.34) and 18% more likely to have achieved a clinically significant change in health-related quality of life (RR 1.18, 95% CI 1.04 to 1.34) on discharge compared to the control group. There was some maintenance of effect for functional independence and health-related quality of life at 6-month follow-up but not at 12-month follow-up. There was no difference in the number of adverse events between the groups (incidence rate ratio = 0.81, 95% CI 0.61 to 1.08).

Providing an additional day of rehabilitation improved functional independence and health-related quality of life at discharge and may have reduced length of stay for patients receiving inpatient rehabilitation. 

Modeling intermittent cycling performance in hypoxia using the critical power concept

PURPOSE: This study investigated the efficacy of an intermittent critical power model, termed the "work-balance" (W'BAL) model, during high-intensity exercise in hypoxia. METHODS: Eleven trained, male cyclists (mean ± SD; age 27 ± 6.6 yr, V[Combining Dot Above]O2peak 4.79 ± 0.56 L.min) completed a maximal ramp test and a 3 min "all-out" test to determine critical power (CP) and work performed above CP (W'). On another day an intermittent exercise test to task failure was performed. All procedures were performed in normoxia (NORM) and hypoxia (HYPO; FiO2 ≈ 0.155) in a single-blind, randomized and counter-balanced experimental design. The W'BAL model was used to calculate the minimum W' (W'BALmin) achieved during the intermittent test. W'BALmin in HYPO was also calculated using CP + W' derived in NORM (N+H). RESULTS: In HYPO there was an 18% decrease in V[Combining Dot Above]O2peak (4.79 ± 0.56 vs 3.93 ± 0.47 L.min ; P<0.001) and a 9% decrease in CP (347 ± 45 vs 316 ± 46 W; P<0.001). No significant change for W' occurred (13.4 ± 3.9 vs 13.7 ± 4.9 kJ; P=0.69; NORM vs HYPO). The change in V[Combining Dot Above]O2peak was significantly correlated with the change in CP (r = 0.72; P=0.01). There was no difference between NORM and HYPO for W'BALmin (1.1 ± 0.9 kJ vs 1.2 ± 0.6 kJ). The N+H analysis grossly overestimated W'BALmin (7.8 ± 3.4 kJ) compared with HYPO (P<0.001). CONCLUSION: The W'BAL model produced similar results in hypoxia and normoxia, but only when model parameters were determined under the same environmental conditions as the performance task. Application of the W'BAL model at altitude requires a modification of the model, or that CP and W' are measured at altitude.

Avaliação clínica do efeito da irradiação pós-opratória do laser de baixa intensidade na cicatrização de gengivoplastias em humanos

Many studies have been made to understand the process of tissular cicatrization, as well as the possible effects of laser therapy in the wound healing. However, the influence of low frequency laser irradiation in the repairing process is not completely understood. Our study has the purpose to assess clinically the effect of postoperative irradiation of the low frequency laser in humans, and the gingival repairing process postgingivoplasty performed with the extern bevel technique. Twenty-four patients with inflammatory gingival hyperplasia were enrolled in this study, which did not reduce with basic periodontal procedures, and patients with melanin pigmentation, with esthetic indications. After surgery the test group, randomly selected by a drawing, received laser application with energy density of 4 J/cm2, immediately after surgery and each 48 hours, during a week, with a total of 4 sections. The control group did not receive irradiation. The visual clinical analyses were performed by a single blind examiner, in the 2nd, 4th, 6th, 8th, 15th and 21st days post surgery. For statistic analyses of the data was used a Q-square test. Concerning the color, the results showed a better wound healing during days 6 to 8. when assessed the degree of progress of surgical wound, the results showed that the test group had a better cicatrization compared with the control group in the 2nd, 6th, 8th and 15th days post surgery, and at the 21st day both groups had the same results. Our results confirm that the laser had clinical influence in the repairing process after gingivoplasty surgery during days 2 to 15 post surgery

Niobium Pentachloride Catalyzed Multicomponent Povarov Reaction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Low-altitude, near-polar and near-circular orbits around Europa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação audiológica em pacientes com doenças reumáticas pediátricas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Low-Fluoride Acidic Dentifrice: A Randomized Clinical Trial in a Fluoridated Area

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)