Lipophilic index, kidney function, and kidney function decline.

BACKGROUND AND AIMS: Unhealthy dietary fats are associated with faster kidney function decline. The cell membrane composition of phospholipid fatty acids (FAs) is a determinant of membrane fluidity and rheological properties. These properties, which have been linked to kidney damage, are thought to be reflected by the lipophilic index (LI). We prospectively investigated the associations of LI with kidney function and its decline. METHODS AND RESULTS: Observational study from the Prospective Investigation of Vasculature in Uppsala Seniors including 975 men and women with plasma phospholipid FAs composition and cystatin-C estimate glomerular filtration rate (eGFR). Of these, 780 attended re-examination after 5 years, and eGFR changes were assessed. Participants with a 5-year eGFR reduction ≥30% were considered chronic kidney disease (CKD) progressors (n = 198). LI was calculated as the sum of the products of the FA proportions with the respective FAs melting points. Blood rheology/viscosity measurements were performed in a random subsample of 559 subjects at baseline. Increased LI showed a statistically significant but overall weak association with blood, plasma viscosity (both Spearman rho = 0.16, p < 0.01), and erythrocyte deformability (rho = -0.09, p < 0.05). In cross-sectional analyses, LI associated with lower eGFR (regression coefficient 3.00 ml/min/1.73 m2 1-standard deviation (SD) increment in LI, 95% CI: -4.31, -1.69, p < 0.001). In longitudinal analyses, LI associated with a faster eGFR decline (-2.13 [95% CI -3.58, -0.69] ml/min/1.73 m2, p < 0.01) and with 32% increased odds of CKD progression (adjusted OR 1.32 [95%, CI 1.05-1.65]). CONCLUSIONS: A high LI was associated with lower kidney function, kidney function decline, and CKD progression.

Body composition in a cohort of Swedish adolescents aged 15, 17 and 20.5 years.

OBJECTIVE: To assess variables of body composition and identify their correlates in a group of individuals studied from adolescence to early adulthood. METHODS: Cross-sectional results were obtained from 203, 149 and 106 subjects at the respective ages. Sixty-two subjects examined at all three ages constituted the longitudinal study group. A cohort of randomly selected 15-year-old adolescents from an industrial town in Sweden was studied by dual energy X-ray absorptiometry (DXA) and followed up at 17 and 20.5 years. Lean body mass (LBM), fat mass (FM) and total body bone mineral content (TBMC) were measured by DXA. Total bone mineral density (TBMD) was calculated. Information of parental educational level, energy intake and food habits, energy expenditure (TEE) and physical activity level (PAL) was obtained by questionnaires and diaries. RESULTS: LBM, TBMC and TBMD increased significantly more in males and FM more in females, from 15 to 20.5 years of age. Body weight, height, TEE, PAL and the fathers' educational level and, at age 15, also gender were identified as significant correlates of the body composition variables. CONCLUSION: New reference values for body composition at ages 15, 17 and 20.5 years are presented and also a finding about an association between the father's educational level and the adolescent's body composition.

Assessing dead space. A meaningful variable?

The recording of dead space will give information on how much of total ventilation that reaches both ventilated and perfused alveoli and thus allows gas exchange between alveoli and pulmonary blood. Realising that CO2 retention can be an effect not only of low total ventilation but also of increased dead space is one important information. Moreover, dead space will give insight into the matching of ventilation and perfusion. This is because dead space is affected by a number of factors: 1) tubings and valves that the subject has to rebreath through (apparatus dead space), 2/ Airways (anatomical dead space), 3/ Non-perfused but ventilated alveoli, e.g. pulmonary embolus (alveolar dead space), 4/ Excessive ventilation of alveoli in relation to their perfusion that can be seen in chronic obstructive lung disease (another form of alveolar dead space), and 5/ So called "shunt dead space" that is an erroneous description of right to left lung shunt that brings the higher CO2 concentration in venous blood to the arterial side thereby producing an arterial-to-end-tidal CO2 difference. The dead spaces 2-5 are called physiological dead space. The recording of dead spaces can be done according to the Riley three-compartment model or by analysis of the expired CO2 curve. However, both are subjected to potential errors that have to be considered to make a dead space recording meaningful. A correct measurement and calculation of the dead space will give valuable information on the ventilatory support of the critically ill patient and can also be a valuable diagnostic tool. It should therefore not be forgotten in the intensive care setting.

Physical activity, energy expenditure and their correlates in two cohorts of Swedish subjects between adolescence and early adulthood.

OBJECTIVE: To assess physical activity and energy expenditure and to identify their correlates during adolescence and early adulthood. DESIGN: In a cohort study, total energy expenditure (TEE) and physical activity level (PAL) were assessed at 15 and 21 y from a 7-day activity diary and predicted BMR. The influences on TEE and PAL of body size, gender, sexual maturity, physical activity habits, sitting time, region, social conditions, employment, food habits, smoking and alcohol intake were examined in multivariate analyses. SUBJECTS: 71 male and 89 female subjects, living in two socioeconomically different regions of Sweden, a university region and an industrial region. SETTING: The university city of Uppsala and the industrial town of Trollhättan. RESULTS: At both 15 and 21 y, PAL and TEE were high, with gender, sitting time and physical activity habits as main correlates. At age 21 y, employment and the mother's educational level also appeared as significant correlates. The relations between the main variables and their correlates were more complex than at age 15 y, and the sitting time was reduced and the activity habits were changed. CONCLUSIONS: A reduction of daily sitting appears to be a major reason why high levels of physical activity and energy expenditure were maintained from 15 to 21 y of age in spite of changed and less frequent activity habits during this interval.

Whole-body mineral measurements in Swedish adolescents at 17 years compared to 15 years of age.

AIM: To provide reference data for bone mineral variables in 15- and 17-y-old adolescents and to analyse the relationships between these variables and measures of bone and body size, gender, puberty, growth, various lifestyle and environmental factors and socioeconomic background. METHODS: In the same 321 randomly selected adolescents (147 boys and 174 girls) living in two different regions of Sweden, the total bone mineral content (TBMC), bone area (BA) and total bone mineral density (TBMD) were assessed by dual-energy X-ray absorptiometry at ages 15 and 17 y. The effects of bone and body size, gender, growth, sexual maturity, physical activity, region of domicile, social conditions, food habits, smoking and alcohol intake on TBMC and TBMD were examined in multivariate analyses. RESULTS: In the 15-y-old adolescents, BA, height, gender, physical activity, maturity and weight explained 91% and 48%, of the variance in TBMC and TBMD, respectively. In similar analyses in the 17-y-olds, the corresponding figures were 92% and 62%, respectively, when BA, height, growth, physical activity, gender and region emerged as significant in the model. In all these analyses, BA explained most of the variance in TBMC and TBMD. No significant reduction of variance was found when different measures of social conditions, smoking, food habits, alcohol or dietary intakes of energy, calcium or vitamin D were included in the models. The reason why region of domicile had a significant impact on TBMC in the 17-y-olds is not known. The fact that the normal fluoride concentration in drinking water (1.1 mg/L) is 10 times higher in the region where TBMC was higher than in the other region is an interesting observation. CONCLUSION: Almost 90% of the variance in TBMC and 50% of that in TBMD was explained by measures of bone and body size and only a few percent by gender, physical activity, Tanner stage, growth and region of domicile.

Do ethanol and deuterium oxide distribute into the same water space in healthy volunteers?

BACKGROUND: The volume of distribution at steady state for ethanol (Vss) is thought to be identical to the total body water (TBW). We compared a two-compartment pharmacokinetic model with parallel Michaelis-Menten and first-order renal elimination with the classical one-compartment zero-order elimination model. Ethanol concentration-time profiles were established for breath, venous blood, and urine. The values of Vss obtained for ethanol were compared with TBW determined by deuterium oxide dilution. METHODS: Sixteen healthy volunteers each received a 30-min intravenous infusion of ethanol on two occasions. Ethanol was measured in breath by a quantitative infrared analyzer and in blood and urine by headspace gas chromatography. Deuterium oxide was given as an intravenous injection and measured in serum by isotope-ratio mass spectrometry. Components of variation were calculated by ANOVA to determine the precision of the estimates of Vss and TBW. RESULTS: Mean TBW, determined by deuterium oxide dilution, was 44.1 +/- 3.9 liters (+/-SD) for men, corresponding to 0.61 liters/kg, and 37.4 +/- 3.2 liters for women, or 0.54 liters/kg. Estimates of Vss from blood-ethanol pharmacokinetics were 87.6% of TBW according to isotope dilution and 84.4% for breath analysis with the two-compartment model. This compares with 95.1% and 95.4% for blood and breath alcohol, respectively, when the classical zero-order kinetic analysis is used. The precision of the estimates of Vss and TBW was between +/-1.56 and +/-2.19 liters (95% confidence interval). CONCLUSIONS: Ethanol does not distribute uniformly into the TBW. The precision of measuring Vss by ethanol dilution was comparable to estimates of TBW by isotope dilution. Results of noninvasive breath ethanol analysis compared well with use of venous blood for estimating Vss. The sophisticated two-compartment model was much superior to the classical one-compartment model in explaining the total concentration-time course of intravenously given ethanol.

Erythropoetin treatment can increase 2,3-diphosphoglycerate levels in red blood cells.

UNLABELLED: Some patients experience an improved well-being during treatment with recombinant human erythropoietin even with an unchanged Hb level. We have hypothesized that this may not be only a placebo effect. 2,3-diphosphoglycerate (2,3-DPG) in red blood cells increases in response to anaemia/hypoxia and causes a shift of the oxygen dissociation curve, allowing a more effective oxygen delivery. We have investigated red cell 2,3-DPG concentrations during erythropoietin treatment in healthy volunteers as a mediator of a possible physiological explanation. Thirteen healthy subjects with no iron deficiency were recruited and randomly assigned to a treatment group comprising five males and three females and a control group including three males and two females. The treatment group was treated with erythropoietin (Recormon), 20 IE/kg subcutaneously three times/week for 4 weeks. Blood samples were collected at each injection day and 10 days after the last injection and at corresponding times in the control group. B-Hb, red cell 2,3-DPG and P50 were measured by standard techniques and oxygen-releasing capacity was calculated. RESULTS: due to the sampling (26 ml each time, three times/week) the mean Hb level was lowered from 140.5 +/- 5.9 to 128.6 +/- 10.4 g/L in the control group whereas the erythropoietin treatment group maintained a mean Hb level of about 142 g/L (p<0.002). The 2,3-DPG mean level curve as well as that for oxygen releasing capacity also differed significantly between the two groups (p < 0.002), the treatment group showing higher levels. CONCLUSION: treatment with erythropoietin causes an increase in red cell 2,3-DPG levels.

Effects of phlebotomy on haemodynamic characteristics during exercise in standardbred trotters with red cell hypervolaemia.

Five Standardbred trotters with red cell hypervolaemia (RCHV) were compared before and after removal of approximately 22% (36 ml/kg bwt) of the total blood volume in order to evaluate the haemodynamic responses, haemorheological alterations and oxygen transport during exercise to fatigue. Data were recorded during submaximal exercise at 4 different speeds on a treadmill and then during continued running at the highest speed step until fatigue. Oxygen uptake (VO2), pulmonary artery pressure (PAP), systemic artery pressure (SAP), heart rate (HR), haematocrit and haemoglobin concentrations (Hb) were measured. Arteriovenous O2 content difference (C(a-v)O2), pulmonary vascular resistance (PVR) and total systemic resistance (TSR) were calculated. Whole blood and plasma viscosity and erythrocyte aggregation tendency were determined with a rotational viscometer. Endoscopy was performed after exercise. ANOVA was used for statistical analysis. Phlebotomy resulted in a decrease in haematocrit and Hb during the course of exercise. Blood and plasma viscosity were lower and erythrocyte aggregation tendency was higher after phlebotomy. Throughout exercise, including submaximal work and continued running to fatigue, PAP, SAP, PVR, TSR and C(a-v)O2 were lower after phlebotomy. HR was higher after phlebotomy during submaximal exercise. Oxygen delivery and VO2 were lower after phlebotomy in the period from submaximal exercise to fatigue. Run time to fatigue was shorter after phlebotomy. Four horses showed exercise-induced pulmonary haemorrhage (EIPH) before phlebotomy and the degree of bleeding was diminished but not abolished after phlebotomy. The reductions in PVR, TSR, PAP and SAP after phlebotomy were probably a result of reduced blood viscosity. In conclusion, although a 22% reduction in blood volume improved the haemodynamic and haemorheological parameters and the degree of EIPH, it was found that RCHV trotters have to rely on high oxygen delivery to the working muscles for maintenance of maximal performance.

Improved hemorheological properties during infusion of a lipid emulsion (Intralipid) in healthy subjects.

OBJECTIVES: Lipid emulsions are commonly used for nutrition in critically ill patients. In these patients interventions resulting in deteriorated blood rheology and thereby an impaired microcirculation may be deleterious. This study examined the acute hemorrheological effects of the lipid emulsion Intralipid. We have recently shown that hyperinsulinemia exerts a negative effect on erythrocyte deformability, and here the effect of hyperinsulinemia combined with Intralipid was studied. SUBJECTS AND INTERVENTIONS: Eleven healthy subjects received Intralipid (200 mg/ml) intravenously as a bolus injection (0.5 ml/kg) over 10 min and thereafter as a continuous intravenous infusion (90 ml/h) for 4 h combined with heparin (200 U/h) to stimulate lipolysis. During the final 2 h an euglycemic hyperinsulinemic clamp was added. Five subjects underwent the same protocol with the exception that saline was given instead of Intralipid and heparin. MEASUREMENTS AND RESULTS: Whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency and fluidity were measured by rotational viscometry. Compared with basal and control values the Intralipid infusion caused greater erythrocyte fluidity (p < 0.05) and less aggregation tendency (p < 0.05). Whole blood and plasma viscosity remained unchanged. Hyperinsulinemia had no significant effect on the hemorrheological variables measured. CONCLUSIONS: Intralipid has no deleterious effects on blood rheology in healthy subjects. Instead, it leads to improved erythrocyte aggregation tendency and fluidity. If the emulsion exerts the same effects in patients with impaired circulation, the use of Intralipid may be beneficial in these patients.

Hemorheologic variables in critical limb ischemia before and after infrainguinal reconstruction.

PURPOSE: Plasma and whole blood viscosity are elevated in patients with intermittent claudication. The objectives of this study were to investigate whether critical limb ischemia influences hemorheologic variables and whether the rheologic variables in blood from the affected limb differ from the general circulation. We also intended to study whether successful infrainguinal reconstruction improved hemorheologic variables. METHODS: Ten consecutive patients with critical limb ischemia (CLI) underwent arterial reconstruction, one patient with profundaplasty and nine patients with bypass procedures. Venous blood was sampled from the antecubital vein (arm) and the femoral vein (leg) of the affected limb 1 day before and 1 month after surgery. Ten control subjects (matched according to age, sex, diabetic status, and renal insufficiency) were also sampled. Whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency, and erythrocyte fluidity (the latter variable describing the deformability of the erythrocytes) were measured by means of rotational viscometry. Erythrocyte volume fraction was also determined. Fibrinogen was measured in the patients with CLI. RESULTS: Erythrocyte fluidity, blood viscosity, and erythrocyte volume fraction were lower in patients with CLI than in control subjects (P <.01, P <.01, and P <.05, respectively). No major differences between cubital and femoral vein blood were seen before or after the operation in patients with CLI or in control subjects. Successful revascularization did not influence the hemorheologic variables, except for a decrease in blood viscosity in femoral vein blood (P <.05). CONCLUSION: Hemorheologic properties was impaired in patients with CLI. Because no differences were seen between the systemic and local circulation and because no major improvement occurred 1 month after arterial reconstruction, other mechanisms besides local tissue ischemia may play a role.

Altered flow properties of blood and increased plasma fibrinogen in cyclosporin-treated renal allograft recipients.

BACKGROUND: Abnormalities in blood rheology may be factors contributing to cardiovascular complications and the progression of renal failure in kidney allograft recipients. The haemorheological variables haematocrit, fibrinogen, whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency and fluidity were measured in 27 cyclosporin A (CyA)-treated patients who had received a renal graft at least 6 months previously. Their creatinine clearance was in the range of 12-92 ml/min/1.73 m2 (mean 55+/-19). The values were compared with those obtained from a control group comprising 20 healthy subjects matched according to age, sex and smoking habits. RESULTS: The haematocrit, plasma fibrinogen, whole blood viscosity, plasma viscosity, erythrocyte aggregation tendency, body mass index (BMI), mean arterial pressure (MAP) and serum triglycerides were increased in the transplanted patients, and the serum high density lipoprotein (HDL)-cholesterol and erythrocyte fluidity decreased. The haemorheological variables were used as dependent variables in a stepwise regression analysis with age, MAP, BMI, urinary albumin excretion rate, blood CyA concentration, creatinine clearance, and serum triglycerides, cholesterol and HDL-cholesterol as independent variables. Plasma fibrinogen was positively correlated with BMI and blood CyA. The whole blood viscosity was positively correlated with blood CyA and negatively with serum HDL-cholesterol. Only serum triglycerides remained correlated with erythrocyte aggregation tendency. CONCLUSIONS: All variables with a known impact on blood viscosity were altered in the present group of renal transplant recipients. Inappropriate regulation of erythrocyte formation, overweight, the use of CyA, high triglycerides and low HDL-cholesterol levels may be factors contributing to this. The importance of impaired flow properties of blood for the development of cardiovascular diseases and transplant glomerulosclerosis needs to be examined.

[Quality assurance of blood gas analysis--a medical risk zone]. / Kvalitetssäkring av blodgasmätning--ett medicinskt riskområde.

Blood gas analysis is fundamental to all intensive care. Although speed is essential for adequate treatment, prognosis and even survival of the patient, precision and consistency of results are equally important prerequisites for correct clinical decision making. Point-of-care testing (POCT) has become one of the predominant fields of blood gas analysis. Although modern technology and instruments are user friendly, special training and continuous updating of staff education are of paramount importance to the reliability of results. The article consists in an outline of quality requirements and discussion of appropriate procedures for assessing and maintaining quality in blood gas analysis.

Effect of normalization of hematocrit on brain circulation and metabolism in hemodialysis patients.

Full correction of anemia with recombinant human erythropoietin (rhEPO) has been reported to reduce the risk of cardiovascular morbidity and mortality and improve the quality of life in hemodialysis (HD) patients. Effects of normalization of hematocrit on cerebral blood flow and oxygen metabolism were investigated by positron emission tomography. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction ratio (rOER), and metabolic rate for oxygen (rCMRO2) were measured in seven HD patients before and after correction of anemia and compared with those in six healthy control subjects. In addition, blood rheology before and on rhEPO therapy was measured in HD patients, which included blood viscosity, plasma viscosity, erythrocyte fluidity, and erythrocyte aggregability. The results showed that plasma viscosity was high (1.51+/-0.19 mPa x s) and erythrocyte fluidity was low (85.8+/-4.8 Pa(-1) x s(-1)), while whole blood viscosity was within the normal range (3.72+/-0.38 mPa x s) before rhEPO therapy. After treatment, the hematocrit rose significantly from 29.3+/-3.3 to 42.4+/-2.2% (P<0.001), accompanied by a significant increase in the whole blood viscosity to 4.57+/-0.16 mPa x s, nonsignificant decrease in erythrocyte fluidity to 79.9+/-7.4 mPa(-1) x s(-1) and nonsignificant change in plasma viscosity (1.46+/-1.3 mPa x s). Positron emission tomography measurements revealed that by normalization of hematocrit, rCBF significantly decreased from 65+/-11 to 48+/-12 ml/min per 100 cm3 (P<0.05). However, arterial oxygen content (caO2) significantly increased from 5.7+/-0.7 to 8.0+/-0.4 mmol/L (P<0.0001), rOER of the hemispheres significantly increased from 44+/-3 to 51+/-6% (P<0.05) and became significantly higher than healthy control subjects (P<0.05). In addition, rCBV significantly increased from 3.5+/-0.5 to 4.6+/-0.6 ml/100 cc brain tissue. The results showed that oxygen supply to the brain tissue increased with normalization of hematocrit, but it was accompanied by increased oxygen extraction in the brain tissue. This may be assumed to be related to the decrease of erythrocyte velocity in the cerebral capillaries as a result of the decreased blood deformability and the increased plasma viscosity.

Red cell fluidity in hypertension.

Rheological findings in essential hypertension are increases in haematocrit, plasma fibrinogen, plasma and whole blood viscosity, and erythrocyte aggregability as well as impaired erythrocyte deformability. Are these abnormalities secondary effects of an increased blood pressure via an increased filtration pressure rendering haemoconcentration or is the initial pressure-increase the result of a deterioration of any of the rheologic variables? Since the diameter of the red cell is about 8.5 microm, and that of the smallest capillaries about 3 microm, the ability of the cell to deform is of vital importance for capillary flow, and a decreased erythrocyte deformability could cause an increased microvascular flow resistance. We found a negative correlation between erythrocyte deformability and fasting insulin and also a decreased erythrocyte deformability in hypertensive patients during a 2 h euglycaemic insulin clamp. Associations between increased intracellular Ca2+ and decreased erythrocyte deformability on one hand and between in vitro insulin and an accumulation of Ca2+ in red blood cells on the other have earlier been shown. Hence, a decreased insulin sensitivity might be one important factor in the development of hypertension acting via an impaired erythrocyte deformability and an increased flow resistance in the microcirculation.

Total energy expenditure and physical activity as assessed by the doubly labeled water method in Swedish adolescents in whom energy intake was underestimated by 7-d diet records.

Swedish children and adolescents may be adopting a sedentary lifestyle with low energy expenditures and intakes, but no quantitative data are available. The purpose of the present study in 50 adolescents aged 15 y was to investigate whether assessment of total energy expenditure (TEE) and physical activity level (PAL) by the doubly labeled water method and indirect calorimetry and estimation of energy intake by a 7-d diet record would indicate physical inactivity. The boys' (n = 25) mean weight was 112% and the girls' (n = 25) was 109% of Swedish reference values from 1976; the mean height of both boys and girls was 102% of those reference values. Mean TEE in the boys and girls, 13.82 +/- 1.90 and 10.70 +/- 1.59 MJ/d, and mean PAL (TEE/basal metabolic rate), 1.89 +/- 0.16 and 1.79 +/- 0.22, respectively, were nonsignificantly higher than corresponding figures from other published studies. Mean energy intake as a percentage of TEE was 81.9 +/- 17.9% in the boys and 78.3 +/- 16.4% in the girls. Significant negative correlations were found both between energy intake as a percentage of TEE and percentage body fat and between energy intake as a percentage of TEE and body mass index. These results add to the evidence that 7-d diet records underestimate energy intake in adolescents, particularly those with a tendency for overweight and increased body fat. The results support indications of a trend of increasing body weight and height in Swedish adolescents, but conflict with the presumptions of low physical activity, low energy expenditure, and low energy intake. These results support the view that current recommendations for energy intake during adolescence are too low.

The required dose of erythropoietin during renal anaemia treatment is related to the degree of impairment in erythrocyte deformability.

BACKGROUND: Renal anaemia is rapidly corrected by recombinant human erythropoietin (rHuEpo) therapy, but the dose required varies greatly. Since impaired erythrocyte deformability may be one factor contributing to the development of renal anaemia, the interrelationship between that variable and the rHuEpo requirement was examined. METHODS: Twenty-five patients treated with hemodialysis and rHuEpo for at least 6 months were included in the study. The Hb value had been stable and the rHuEpo dose unchanged the last two months. Using a rotational viscometer, the fluidity of erythrocytes, separated from plasma and re-suspended in isotonic buffered saline to a standardized haematocrit, was taken as a measure of erythrocyte deformability. RESULTS: The average weekly dose of s.c. epoetin alpha was 186 +/- 93 U/kg body weight (range 56-370). The dose was correlated to the reticulocyte fraction (R = 0.69, P = 0.0001). When the rHuEpo dose was used as dependent variable and blood haemoglobin concentration, serum (S) albumin, S ferritin, S aluminium, S PTH, S urea, Kt/V/week, erythrocyte fluidity, and plasma viscosity were used as independent variables in a stepwise multiple regression analysis, only erythrocyte fluidity remained significantly negatively correlated to the rHuEpo dose (R = 0.5, P = 0.01). Despite a tendency towards higher doses of rHuEpo in patients with a C-reactive protein concentration exceeding 20 mg/l, the Hb was lower in these patients. CONCLUSIONS: We conclude that the interindividual differences in bone marrow response to rHuEpo were small in these patients. Impaired erythrocyte deformability and inflammation seem to be factors associated with increased rHuEpo requirement.

A 7-day activity diary for assessment of daily energy expenditure validated by the doubly labelled water method in adolescents.

OBJECTIVES: To validate the use of an activity diary and predicted BMR for assessment of daily total energy expenditure (TEE) and physical activity level (PAL = TEE/BMR) in adolescents. DESIGN: TEE and PAL estimated from activity diary records kept for seven days and BMR predicted from age, gender and body weight were compared with the results of doubly labelled water (DLW) measurements and indirect calorimetry performed during the same time period. SETTING: The Unit of paediatric Physiology of the Department of Clinical Physiology, University Hospital, Uppsala, Sweden. SUBJECTS: Fifty randomly selected 15 y old adolescents (25 boys and 25 girls). RESULTS: The mean difference between TEE estimated in all adolescents by the activity diary and by DLW methods was 1.2%. The limits of agreement (mean difference 2 s.d.) were -3.47 and 3.77 MD/d, equivalent to a coefficient of variation of 15%. The mean difference between PAL assessed by activity diary records and by DLW measurements was 0.001, and the limits of agreement between the two methods were 0.54. CONCLUSIONS: The results imply that the activity diary method provides a close estimate of TEE and PAL in population groups.

Daily energy expenditure and physical activity assessed by an activity diary in 374 randomly selected 15-year-old adolescents.

OBJECTIVES: To assess the average daily levels of physical activity, energy expenditure and the time and energy spent a different activities in two cohorts of Swedish adolescents. DESIGN: Total energy expenditure (TEE) and physical activity level (PAL = TEE/basal metabolic rate (BMR)) were estimated in 374 randomly selected healthy adolescents living with two different regions of Sweden on the basis of a seven-day activity diary (AD) and predicted BMR. A validation of the estimates from the AD with the doubly labelled water (DLW) method in a randomly selected subsample of 50 of these subjects is presented elsewhere. SETTING: The Unit of Paediatric of the Department of Clinical Physiology, University Hospital, Uppsala and the Department of Paediatrics, Northern Alvsborg Hospital, Trollhättan, Sweden. RESULTS: No significant differences in TEE and PAL were found between the adolescents of the two regions. High levels of TEE (14.2 and 10.9 MJ/d in boys and girls, respectively) and PAL (1.95 and 1.80) were observed. There was a close association between the PAL and the adolescents and their reported time spent sitting. Those with the lowest PAL values spent 3-6 h longer each day sitting compared to those with the highest PAL values. The results also indicate that everyday activities such as walking and bicycling have a crucial impact on the PAL values. CONCLUSIONS: In the 15 y old adolescents of the two studied regions of Sweden, high and concordant levels of energy expenditure and physical activity were found.

Anemia associated with advanced prostatic adenocarcinoma: effects of recombinant human erythropoietin.

BACKGROUND AND METHODS: Nine patients with hormone-refractory metastatic prostatic adenocarcinoma and anemia were treated with recombinant human erythropoietin (rHuEpo) at a median dose of 150 U/kg BW 3 times a week subcutaneously. Baseline hemoglobin (Hb) ranged from 70 to 116 g/L, and the study duration was 12 weeks (median patient participation period was 8 weeks). RESULTS: Four patients demonstrated a median Hb increase of 20 g/L and were considered responders. Three patients showed a median increase of 17 g/L but required blood transfusion once, and were therefore considered as partial responders. Baseline erythropoietic status showed a significant correlation between serum Epo and Hb. Inadequate Epo production, evaluated by the observed/predicted log Epo ratio, was found in two patients. Defective bone marrow activity, demonstrated by low transferrin receptor (TfR), and hypoferremia in spite of abundant iron stores were also shown. Hemorheological investigations showed elevated plasma viscosity. CONCLUSIONS: Our results indicate that suppression of erythropoiesis can be mainly explained by the depressed marrow activity. The altered hemorheology might contribute to the anemia. This anemia could possibly be corrected with rHuEpo.