Doppler evaluation of blood flow of the lower limb

Regional blood flow measurement in the limbs (BFLL) is of special interest in order to evaluate the consequences of hypertension. The purpose of this study is to assess the interest of the Doppler ultrasound method in the BFLL measurement among normotensive or borderline hypertensives young male adults. BFLL reproducibility was evaluated among 23 healthy subjects aged 21 +/- 2 y, height 177 +/- 8 cm, weight 75 +/- 13 kg at day one (D1) and three day later (D3). Measurements were made basically after 20 minutes lying at rest and after cold pressor test (CPT). BFLL estimation depends on common femoral artery diameter (FAD) echographic measurement at the thigh root and on velocity time interval (VTI) calculation with pulsed wave doppler using controlled incident angle and sample volume. The following parameters were measured: mean arterial pressure (MAP) using Dinamap, heart rate (HR), FAD, common femoral artery cross sectorial area (A), VTI and peripheral arteriolar resistances (PAR). Basic and CPT results at D1 and D3 were compared using paired "t" test. Results: [table: see text] Comparisons between basic state and CPT demonstrate a significant decrease of VTI and BFLL, a significant increase of PAR. D remained unchanged. Doppler ultrasound method is easy to use. Systolic femoral volume measurement is relatively insensitive to small transducer positioning variations so that the method reproducibility is satisfactory.     

Five years' experience of intrauterine contraception with the Nova-T and the Copper-T-200

A randomized study was performed for the comparison of two copper-releasing intrauterine contraceptive devices (IUDs), the Nova-T and the Copper-T-200, simultaneously in Denmark, Finland, and Sweden. Five years' experience demonstrated that Nova-T users had a significantly lower pregnancy rate than Copper-T-200 users. The Pearl index over 5 years was 0.8 for Nova-T users and 2.0 for Copper-T users. The performance and tolerance of the Nova-T were less affected by parity and age than was the performance of the Copper-T. Infections were treated by removal of the device and with antibiotics. The cumulative rate of removals because of infections and suspected infections was below 5 with both devices over 5 years. The copper wire in the Nova-T has a silver core which prevents corrosion-induced fragmentation of the wire. Hence, the effective lifetime of this device is more than 5 years. The results indicate that the Nova-T, which is easy to insert and remove and is associated with a low pregnancy rate and a low medical termination rate, is a real improvement over other IUDs.     

Early puerperal insertions of Copper-T-200

The Copper-T-200 (CuT-200) was inserted after delivery at term in 197 women on the day preceding discharge from the hospital. The majority of the insertions were done on day 5 or 6 after delivery. Every subject in the study was followed more than 12 months. The insertions were well tolerated; no perforations or serious side effects occurred. During the first year of use, only 9 infections were recorded. The first segment pregnancy rate (7.2) and expulsion rate (14.8) were significantly higher and the continuation rate, 69.5, lower than that obtained with the same device inserted in postmenstrum women. The expulsions were mainly partial (11.1), and were discovered during the first and second months postpartum. The postpartum insertions were found to be safe and well accepted. The high pregnancy and expulsion rates make the CuT-200 an unsuitable IUD in postpartum programs where follow-up is not adequate and early removals of partially expelled or displaced devices is not possible.     

Randomized comparison of clinical performance of two copper-releasing IUDs, Nova-T and Copper-T-200, in Denmark, Finland and Sweden.

A randomized study was conducted simultaneously in three countries to compare the clinical performance of two new IUDs, the Nova-T and Copper-T-200. Forty-four persons, midwives, general practitioners, residents and specialists in obstetrics and gynecology inserted 907 Nova-Ts and 936 Copper-Ts. The pregnancy rate of Nova-T (0.7 at one year) was significantly lower than that of Copper-T (2.2 at one year). No significant differences were observed in other termination rates. The continuation rates were 72.6 for Nova-T and 71.3 for Copper-T-200. The total experience was based on 18,035 woman months of use, with a lost to follow-up of less than 7 per cent for both IUDs.     

The concept of maximal lactate steady state: a bridge between biochemistry,physiology and sport science

The maximal lactate steady state (MLSS) is defined as the highest blood lactate concentration (MLSSc) and work load (MLSSw) that can be maintained over time without a continual blood lactate accumulation. A close relationship between endurance sport performance and MLSSw has been reported and the average velocity over a marathon is just below MLSSw. This work rate delineates the low- to high-intensity exercises at which carbohydrates contribute more than 50% of the total energy need and at which the fuel mix switches (crosses over) from predominantly fat to predominantly carbohydrate. The rate of metabolic adenosine triphosphate (ATP) turnover increases as a direct function of metabolic power output and the blood lactate at MLSS represents the highest point in the equilibrium between lactate appearance and disappearance both being equal to the lactate turnover. However, MLSSc has been reported to demonstrate a great variability between individuals (from 2-8 mmol/L) in capillary blood and not to be related to MLSSw. The fate of enhanced lactate clearance in trained individuals has been attributed primarily to oxidation in active muscle and gluconeogenesis in liver. The transport of lactate into and out of the cells is facilitated by monocarboxylate transporters (MCTs) which are transmembrane proteins and which are significantly improved by training. Endurance training increases the expression of MCT1 with intervariable effects on MCT4. The relationship between the concentration of the two MCTs and the performance parameters (i.e. the maximal distance run in 20 minutes) in elite athletes has not yet been reported. However, lactate exchange and removal indirectly estimated with velocity constants of the individual blood lactate recovery has been reported to be related to time to exhaustion at maximal oxygen uptake.     

How do tutors intervene when conflicts on knowledge arise in tutorial groups?

Recent research on problem-based learning (PBL) has shown that students need support when dealing with conflicting ideas in PBL-tutorial discussions. In the present study, we examined tutor facilitation during tutorial discussions, and particularly how the facilitation helped students to collaboratively resolve conflicts on knowledge. The study involved four PBL-tutorial sessions that included altogether 33 first-year medical and dental students. The sessions were videotaped and analysed using qualitative interaction analysis. Our aim was to find out how the tutor interventions encouraged students to elaborate on conflicting ideas, and how the interventions differed between conflict and non-conflict situations. We also examined how the tutors intervened during conflicts about factual or conceptual knowledge. The tutorial discussions included 92 tutor intervention episodes and 43 conflict episodes. The tutors intervened during 24 of the conflict episodes and resolved 13 of these episodes. Generally, the tutors often intervened by confirming what the students had said or by giving explanations, but they rarely asked questions that would stimulate the elaboration of knowledge. During conflicts on knowledge the tutors gave more explanations, but did little to encourage the students to deal with conflicting ideas. The tutors more often resolved conflicts on factual knowledge than conceptual knowledge. The findings suggest that tutor training should focus on promoting tutors’ understanding on when to give direct explanations, and when and how to encourage students to collaboratively elaborate on conflicting ideas.     

Chromium supplementation in impaired glucose tolerance of elderly: effects on blood glucose, plasma insulin, C-peptide and lipid levels.

Altogether twenty-six elderly subjects (aged 65-74 years) with persistent impaired glucose tolerance (World Health Organization (1985) criteria) identified in a population-based study, were randomly treated either with chromium-rich yeast (160 micrograms Cr/d) or with placebo for 6 months. The 24 h urinary Cr increased from 0.13 (SE 0.03) to 0.40 (SE 0.06) micrograms/d in the Cr group (n 13) but no change was found in the placebo group (n 11) (0.13 (SE 0.02) v. 0.11 (SE 0.02) micrograms/d). No significant change was observed in the oral glucose tolerance test (glucose dose 75 g; 0, 1 and 2 h blood glucose respectively): 5.3 (SE 0.1), 9.3 (SE 0.3), 8.2 (SE 0.3) mmol/l v. 5.0 (SE 0.1), 8.5 (SE 0.4), 7.3(SE 0.5) mmol/l in the Cr group; 4.9 (SE 0.2), 9.2 (SE 0.6), 8.1 (SE 0.3) mmol/l v. 4.8 (SE 0.2), 8.5 (SE 0.5), 7.0 (SE 0.6) mmol/l in the placebo group (baseline v. 6 months). Glycosylated haemoglobin, plasma insulin, C-peptide and apolipoprotein A1 and B levels remained unchanged, and no improvement was seen in serum total cholesterol (6.2 (SE 0.3) v. 6.4 (SE 0.3) mmol/l for the Cr group, 6.2 (SE 0.4) v. 6.5 (SE 0.3) mmol/l for the placebo group), high-density-lipoprotein-cholesterol (1.1 (SE 0.1) v. 1.2 (SE 0.1) mmol/l for the Cr group, 1.0 (SE 0.1) v. 1.1 (SE 0.1) mmol/l for the placebo group) or triacylglycerols (2.5 (SE 0.4) v. 2.0 (SE 0.4) mmol/l for the Cr group, 2.4 (SE 0.2) v. 2.5 (SE 0.2) mmol/l for the placebo group). The present results indicate that Cr supplementation does not improve glucose tolerance or serum lipid levels in elderly subjects with stable impaired glucose tolerance.     

Calpastatin overexpression in the skeletal muscle of mice prevents clenbuterol-induced muscle hypertrophy and phenotypic shift

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n-3 Fatty acids and 5-y risks of death and cardiovascular disease events in patients with coronary artery disease

BACKGROUND: Data on the association of n-3 fatty acid content in serum lipids with mortality in patients with coronary artery disease (CAD) are limited. OBJECTIVE: We hypothesized that a high proportion of n-3 fatty acids in serum lipids would be associated with reduced risks of death and coronary events in patients with established CAD. DESIGN: We measured dietary intakes via food records and the fatty acid composition of serum cholesteryl esters (CEs) in 285 men and 130 women with CAD (x age: 61 y; range: 33-74 y). The patients participating in the EUROASPIRE (European Action on Secondary Prevention through Intervention to Reduce Events) study were followed up for 5 y. RESULTS: During the follow-up, 36 patients died, 21 had myocardial infarctions, and 12 had strokes. The relative risks (RRs) of death adjusted for cardiovascular disease risk factors for subjects in the highest tertile of fatty acids in CEs compared with those in the lowest tertile were 0.33 (95% CI: 0.11, 0.96) for alpha-linolenic acid, 0.33 (0.12, 0.93) for eicosapentaenoic acid, and 0.31 (0.11, 0.87) for docosahexaenoic acid (P for trend = 0.063, 0.056, and 0.026, respectively). A high proportion of eicosapentaenoic acid in CEs was associated with a low risk of CAD death. Compared with no consumption, consumption of fish tended to be associated with a lower risk of death [1-57 g/d, RR = 0.50 (0.20, 1.28); > 57 g/d, RR = 0.37 (0.14, 1.00); P for trend = 0.059]. CONCLUSION: High proportions of n-3 fatty acids in serum lipids are associated with a substantially reduced risk of death.