1 Prospective associations of aerobic fitness and lipoprotein subclasses in a cohort of norwegian schoolchildren: the active smarter kids (ASK) study

Aim

Aerobic fitness is associated with cardiometabolic risk factors in children. Associations with traditional measures of lipid metabolism are uncertain. We investigated whether higher levels of fitness benefit lipid metabolism by exploring cross-sectional and prospective associations between aerobic fitness and a comprehensive lipoprotein profile.

Methods

We used targeted proton nuclear magnetic resonance (1H NMR) spectroscopy to profile 29 measures of lipoprotein metabolism for 811 fifth-grade Norwegian schoolchildren (50.1% girls; mean age 10.2 years). Serum samples were taken on two occasions across the academic year. Aerobic fitness was measured at baseline using the Andersen aerobic fitness test. We used multiple linear regression adjusted for potential confounders to examine both cross-sectional and prospective — adjusted for baseline lipoprotein measure — associations between aerobic fitness and lipoprotein profiles.

Results

Higher levels of aerobic fitness were associated with all measures of lipoprotein metabolism in the cross-sectional analysis. There were inverse associations with the apolipoprotein B-containing (apo B) lipoprotein subclasses, including cholesterol and triglyceride concentration. The associations between aerobic fitness and the concentration of high-density lipoprotein (HDL) particles were divergent between larger and smaller subclasses. In the prospective analysis, the inverse associations between aerobic fitness and the measures of larger apo B-containing lipoprotein subclasses persisted as did all but one of the associations with triglyceride concentrations. Additional adjustment for adiposity attenuated most associations in both cross-sectional and prospective models, but an independent effect of fitness remained for certain measures.

Conclusions

Higher levels of aerobic fitness are associated with a favourable lipoprotein profile, partly independent of adiposity. Associations tended to be stronger and more consistent over time for the larger apo B-containing lipoprotein measures and those of triglyceride concentration. Our results suggest that improving children’s fitness levels should have beneficial effects on lipoprotein metabolism, though a concomitant reduction in adiposity would likely be more effective.

References

Anderssen SA, Cooper AR, Riddoch C, Sardinha LB, Harro M, Brage S, et al. Low cardiorespiratory fitness is a strong predictor for clustering of cardiovascular disease risk factors in children independent of country, age and sex. Eur J Cardiovasc Prev Rehabil 2007.

Mintjens S, Menting MD, Daams JG, van Poppel MNM, Roseboom TJ, Gemke RJBJ. Cardiorespiratory fitness in childhood and adolescence affects future cardiovascular risk factors: a systematic review of longitudinal studies. Sports Med 2018 Nov 1;48(11):2577–605.

Optimizing OCT acquisition parameters for assessments of vitreous haze for application in uveitis

Detection and evaluation of inflammatory activity in uveitis is essential to the management of the condition, and yet continues to be largely dependent on subjective clinical measures. Optical coherence tomography (OCT) measurement of vitreous activity is an alternative to clinical vitreous haze scoring and has passed a number of early validation studies. In this study we aimed to evaluate the impact of ‘operator factors’ on the variability of the technique as part of the validation process, and to help evaluate its suitability for ‘real world’ use. Vitreous haze index was calculated as a ratio between the reflectivity of the vitreous and of the outer retina in each scan. Different scanning conditions were tested and their effect on the measurement is reported. Our results show that the ‘quantitative imaging’ technique of OCT-measured vitreous activity had good reliability in normal subjects under a range of ‘real world’ conditions, such as when the operator changes the averaging value. The technique was however vulnerable to highly inaccurate focussing or abnormal downward displacement of the image. OCT-based quantification of vitreous activity is a promising alternative to current subjective clinical estimates, with sufficient ‘tolerance’ to be used in routine clinical practice as well as clinical trials.

Association of availability of tobacco products with socio-economic and racial/ethnic characteristics of neighbourhoods

OBJECTIVE

To examine the association of neighbourhood median income and racial/ethnic composition with the availability of tobacco products in Omaha Metropolitan Area, Nebraska, USA.

METHODS

A total of 94 census tracts were selected at random. The outcome measures were the percentage of stores that sold tobacco and the number of stores that sold tobacco per square mile in each census tract.

RESULTS

Median household income was negatively associated (P<0.001), and percentage African American population (P<0.001) and percentage Hispanic population (P=0.049) were positively associated with the percentage of stores that sold tobacco. Median household income was negatively associated (P<0.001) and percentage Hispanic population (P=0.012) was positively associated with the number of stores that sold tobacco per square mile.

CONCLUSION

Policies that reduce the number of tobacco outlets might reduce social disparities in tobacco use.

Effectiveness of web-based interventions in achieving weight loss and weight loss maintenance in overweight and obese adults: a systematic review with meta-analysis

The objectives of this systematic review are to evaluate the effectiveness of web-based interventions on weight loss and maintenance and identify which components of web-based interventions are associated with greater weight change and low attrition rates. A literature search from 1995 to April 2008 was conducted. Studies were eligible for inclusion if: participants were aged >or=18 years with a body mass index >or=25, at least one study arm involved a web-based intervention with the primary aim of weight loss or maintenance, and reported weight-related outcomes. Eighteen studies met the inclusion criteria. Thirteen studies aimed to achieve weight loss, and five focused on weight maintenance. Heterogeneity was evident among the studies with seven research questions examined across interventions of varying intensity. Seven studies were assessed for effectiveness based on percentage weight change, with four studies deemed effective. Although the four meta-analyses suggest meaningful weight change, it is not possible to determine the effectiveness of web-based interventions in achieving weight loss or maintenance due to heterogeneity of designs and thus the small number of comparable studies. Higher usage of website features may be associated with positive weight change, but we do not know what features improve this effect or reduce attrition.

Racial/ethnic and socioeconomic variations in duration of smoking: results from 2003, 2006 and 2007 Tobacco Use Supplement of the Current Population Survey

BACKGROUND

Little is known about racial/ethnic and socioeconomic variations in the duration of smoking. The goal of this research was to examine these variations.

METHODS

Data came from the 2003, 2006 and 2007 Tobacco Use Supplement of the Current Population Survey. The analysis was limited to ever-smokers (n = 117,168). The outcome was number of years of daily smoking. Survival analysis was employed to predict smoking duration.

RESULTS

American Indians with 32 years had the highest median duration of smoking, followed by Blacks and 'other' races with 30 years, Whites with 28 years and Hispanics with 24 years. The difference in the duration of smoking between Blacks and Whites disappeared after adjusting for poverty. Individuals in poverty had a median duration of smoking of 40 years, while those with a family income of at least three times that of the poverty threshold had a median duration of 22 years. Median duration of smoking was 40 years among individuals without a high-school diploma and 18 years among those with a bachelors or higher degree.

CONCLUSION

This research revealed large variations in smoking duration between racial/ethnic and socioeconomic groups. Longer exposure to tobacco among groups that are already disadvantaged is likely to exacerbate existing health disparities.

Resistance to an herbivore through engineered cyanogenic glucoside synthesis

The entire pathway for synthesis of the tyrosine-derived cyanogenic glucoside dhurrin has been transferred from Sorghum bicolor to Arabidopsis thaliana. Here, we document that genetically engineered plants are able to synthesize and store large amounts of new natural products. The presence of dhurrin in the transgenic A. thaliana plants confers resistance to the flea beetle Phyllotreta nemorum, which is a natural pest of other members of the crucifer group, demonstrating the potential utility of cyanogenic glucosides in plant defense.

Activation of diacetyldapsone and a preliminary evaluation of a cyclodextrin-diacetyldapsone complex in cultured lung cells

A diacetyldapsone-2-hydroxypropyl-beta-cyclodextrin complex (DADDS-CD) was evaluated with regard to the ability of cultured lung cells to activate DADDS to the active metabolite dapsone. The same system was used to assess the effect of the complex on cell growth. The complex was incubated with cells for periods of 24 to 72 h, followed by extraction of metabolites from the incubation medium and analysis by HPLC. In addition, the Trypan Blue exclusion technique was used to assess cell viability during this time period. Results indicated that lung cells could activate DADDS to dapsone and that, while the complex appeared to delay cell growth in the first 24 h period, no significant difference was seen between cells incubated in the presence and absence of the complex at 72 h. These results indicate that DADDS-CD has significant potential as a drug-delivery system for DADDS in the lung based upon the ability of the cells to activate DADDS. The mixed effects of the complex on cell growth may have important implications when considering the frequency of administration of the complex to the lung.

Commencing, continuing and stopping brisk walking: effects on bone mineral density, quantitative ultrasound of bone and markers of bone metabolism in postmenopausal women

Regular walking is associated with reduced risk of fracture and, in our recent randomized trial, reduced calcaneal bone loss relative to controls. The present follow-up study compared the effects on dual-energy X-ray absorptiometry, ultrasound and biochemical indices of bone density and metabolism of (i) taking up (ii) continuing with and (iii) ceasing brisk walking for exercise. Subjects were 68 postmenopausal women aged 60-70 years. Twenty previously sedentary women remained sedentary (Sed/Sed) whilst 17 took up brisk walking (Sed/Walk). Fifteen women who had been walking regularly for 1 year returned to their former sedentary lifestyle (Walk/Sed), whilst 16 continued brisk walking over a second year (Walk/Walk). Bone mineral density (BMD), broadband ultrasonic attenuation (BUA), and biochemical markers of bone formation (serum osteocalcin, C-terminal propeptide of type I collagen and bone alkaline phosphatase) and resorption (urinary deoxypyridinoline) were assessed at baseline and 12 months. Women in the Sed/Walk and Walk/Walk groups completed a mean (SEM) of 16.9 (0.7) and 20.8 (1.2) min of brisk walking per day, respectively. Changes in BMD did not differ significantly between groups. Calcaneal BMD decreased significantly in Walk/Sed women [by 2.7 (1.4)%; p = 0.01] whilst changes in other groups were not significant. Calcaneal BUA increased significantly (p = 0.02) in Sed/Walk women [by 7.4 (3.3)%] relative to other groups. Urinary deoxypyridinoline increased over the year in the Sed/Sed group but there were no significant changes in biochemical markers in other groups. Women taking up brisk walking for exercise showed no change in BMD but a significant increase in calcaneal BUA. There was no significant effect on BMD or BUA of continuing brisk walking but calcaneal BMD declined on ceasing brisk walking. Bone resorption increased in sedentary women but not exercisers, suggesting the effect on exercise on bone in postmenopausal women could be through amelioration of this increased turnover.

Prior exercise and postprandial substrate extraction across the human leg

Prior exercise decreases postprandial plasma triacylglycerol (TG) concentrations, possibly through changes to skeletal muscle TG extraction. We measured postprandial substrate extraction across the leg in eight normolipidemic men aged 21-46 yr. On the afternoon preceding one trial, subjects ran for 2 h at 64 +/- 1% of maximal oxygen uptake (exercise); before the control trial, subjects had refrained from exercise. Samples of femoral arterial and venous blood were obtained, and leg blood flow was measured in the fasting state and for 6 h after a meal (1.2 g fat, 1.2 g carbohydrate/kg body mass). Prior exercise increased time averaged postprandial TG clearance across the leg (total TG: control, 0.079 +/- 0.014 ml.100 ml tissue(-1).min(-1) ; exercise, 0.158 +/- 0.023 ml.100 ml tissue(-1).min(-1), P <0.01), particularly in the chylomicron fraction, so that absolute TG uptake was maintained despite lower plasma TG concentrations (control, 1.53 +/- 0.13 mmol/l; exercise, 1.01 +/- 0.16 mmol/l, P < 0.001). Prior exercise increased postprandial leg blood flow and glucose uptake (both P < 0.05). Mechanisms other than increased leg TG uptake must account for the effect of prior exercise on postprandial lipemia.

The significance of definitions of success in program evaluation

In program evaluation, determining whether a program is reaching its goals is key to evaluating program success. Having an understanding of the stated goals of each organization within a system rather than simply knowing the formal system goals can aid in program development and inform policy making. Evaluability assessments were used initially as a means of learning how Philadelphia delinquency prevention programs define success. Subsequent surveys of programs were conducted to ascertain whether any changes in definitions of success had occurred. Examination of programs' definitions of success over time has facilitated program development and policy making.

Reliability of Allen's test in selection of patients for radial artery harvest

BACKGROUND

Allen's test is widely used to assess the ulnar collateral blood supply of the hand before radial artery harvest for coronary bypass surgery. This study was performed to determine the optimum cut-off point for a positive Allen's test and the clinical reliability of Allen's test in this role.

METHODS

Patients undergoing coronary artery bypass surgery were examined by independent observers using both Allen's test and a Doppler ultrasound test of the ulnar collateral circulation.

RESULTS

We examined 93 hands in 47 patients; mean age was 63.6 years. Receiver operating characteristic analysis found that at a conventional cut-off of 6 seconds on Allen's test had a sensitivity of 54.5%, specificity of 91.7%, and diagnostic accuracy of 78.5%. At a cut-off of 5 seconds diagnostic accuracy was maximal (79.6%), with sensitivity of 75.8% and specificity of 81.7%; 100% sensitivity occurred at a cut-off of 3 seconds, with specificity of 27% and diagnostic accuracy of 52%.

CONCLUSIONS

At no cut-off point does Allen's test perform satisfactorily as a discriminatory test. It should be replaced by more objective tests, such as Doppler ultrasound.

Does vitamin D receptor polymorphism influence the response of bone to brisk walking in postmenopausal women?

Vitamin D receptor (VDR) polymorphism may be a genetic factor affecting bone mineral density (BMD). This study examined the interaction of VDR genotype with the effect of an exercise intervention on bone measurements in UK postmenopausal women. 33 walkers, who completed 20.4 +/- 3.9 (mean +/- SD) min day-1 of brisk walking over 1 year, and 36 controls agreed to give DNA samples. BMD was measured at the lumbar spine, femoral neck and calcaneus by dual energy X-ray absorptiometry and broadband ultrasonic attenuation (BUA) was measured at the calcaneus. VDR genotype was determined by BsmI restriction fragment length polymorphisms and the presence, or absence, of the restriction site was signified by 'b' or 'B', respectively. At baseline there was no significant difference in BMD between VDR genotypes, but BUA was significantly higher in the BB genotype than in the Bb or bb genotype. Although there was no significant difference in 1-year change (%) in BMD and BUA between the three genotypes, the 1-year changes in spinal BMD and BUA in the bb walkers (0.75 and 2.35%, respectively) were significantly different from those in the bb controls (-1.25 and -6.10%, respectively). These results suggest that in the bb genotype of VDR, bone may be more responsive to exercise than in other VDR genotypes in British postmenopausal women.

Brisk walking and postural stability: A cross-sectional study in postmenopausal women

This study compared body sway, a measure of postural stability, between regular brisk walkers and control subjects. Furthermore, the relationship between body sway and physical activity duration in postmenopausal women was examined. Subjects were 31 healthy postmenopausal women, aged 61-71 years. They were recruited from a randomized controlled study of the influence of brisk walking on bone: 16 women had been completing 20 min d-1 brisk walking, whilst 15 controls had been completing habitual activities only. Body sway was measured using a swaymeter that measured displacement at the waist whilst subjects stood on a compliant surface, with eyes closed, for 1 min. The activity was measured using activity monitors which were worn at the waist for 3 consecutive days. Body sway (eyes closed, standing on a compliant surface) was lower in walkers than in controls: 2,958 +/- (SE) 270 versus 5,225+/-371 mm2 min-1, respectively (p < 0.05). A negative correlation was found between body sway and minutes of physical activity (r = -0.47, p < 0.01). Analysis of variance revealed that body sway differed significantly (p < 0.05) between groups of differing physical activity participation, being 4,839 +/- 499, 4,167 +/- 516, and 2,877 +/- 362 mm2 min-1, respectively, in women completing <20, 20-40, and >40 min d-1 of physical activity. Body sway was significantly lower in the most active group than in the least active (p < 0.01). These data suggest that postural stability is better in regular walkers than in control subjects. Furthermore, a dose-response relationship was observed between physical activity and postural stability in postmenopausal women. These findings provide a preliminary indication that brisk walking, a low-cost and acceptable form of physical activity for the elderly, could be incorporated into strategies for improving balance in the elderly.

Pharmacokinetics of midazolam in critically ill pediatric patients

Midazolam is frequently used to produce sedation in critically ill pediatric patients. We studied the pharmacokinetics of midazolam in 22 patients (age 8 days to 16 years). The intravenous infusion rate to produce sedation ranged from 49-385 mcg/kg/hr. The blood samples were obtained at steady-state and midazolam was measured by gas chromatography with electron capture. The steady-state plasma concentrations of midazolam ranged from 49-385 ng/mL. The total clearance, apparent volume of distribution, and elimination half-life ranged from 0.1-3.1 L/kg/hr, 0.2-3.5 L/kg, and 0.3-10.9 hours, respectively. The marked interpatient variability in pharmacokinetics explains in part, the substantial variation in dosage requirements of midazolam to produce sedation in critically ill pediatric patients.

Nitric oxide delivery to the lung: a model

Dedicated nitric oxide equipped ventilators are now available commercially but are not yet common in clinical practice. With other ventilators, there is no standardized procedure for the administration or monitoring of nitric oxide. We describe the use of nitric oxide in conjunction with a simple time-cycled, pressure regulated, flow generating ventilator attached to a model infant-sized lung. The measured nitric oxide concentrations were always less than calculated. Infusion site, minute ventilation and sampling port all affected nitric oxide concentration (P < 0.05). Increasing minute ventilation lowered measured nitric oxide concentration exponentially. Mixing of gases improved when nitric oxide was infused closer to the ventilator. Acid contamination was found in water samples from humidifier, water trap and ventilator gas outlet. Acidification was reduced, without change in measured nitric oxide delivery, when infused prehumidifier. We recommend, when used as therapy, nitric oxide levels in inspired gases should always be measured.

The UDP-glucose:p-hydroxymandelonitrile-O-glucosyltransferase that catalyzes the last step in synthesis of the cyanogenic glucoside dhurrin in Sorghum bicolor. Isolation, cloning, heterologous expression, and substrate specificity

The final step in the biosynthesis of the cyanogenic glucoside dhurrin in Sorghum bicolor is the transformation of the labile cyanohydrin into a stable storage form by O-glucosylation of (S)-p-hydroxymandelonitrile at the cyanohydrin function. The UDP-glucose:p-hydroxymandelonitrile-O-glucosyltransferase was isolated from etiolated seedlings of S. bicolor employing Reactive Yellow 3 chromatography with UDP-glucose elution as the critical step. Amino acid sequencing allowed the cloning of a full-length cDNA encoding the glucosyltransferase. Among the few characterized glucosyltransferases, the deduced translation product showed highest overall identity to Zea mays flavonoid-glucosyltransferase (Bz-Mc-2 allele). The substrate specificity of the enzyme was established using isolated recombinant protein. Compared with endogenous p-hydroxymandelonitrile, mandelonitrile, benzyl alcohol, and benzoic acid were utilized at maximum rates of 78, 13, and 4%, respectively. Surprisingly, the monoterpenoid geraniol was glucosylated at a maximum rate of 11% compared with p-hydroxymandelonitrile. The picture that is emerging regarding plant glucosyltransferase substrate specificity is one of limited but extended plasticity toward metabolites of related structure. This in turn ensures that a relatively high, but finite, number of glucosyltransferases can give rise to the large number of glucosides found in plants.

The effect of childhood spinal cord injury on skeletal development: a retrospective study

STUDY DESIGN

Cross-sectional clinical review.

OBJECTIVES

To assess the relationship between late spinal deformity in childhood onset spinal cord injury (SCI) and level of spinal cord lesion, severity of lesion, age at onset, duration of paralysis and pelvic deformities.

SETTING

People with spinal cord injury (onset in childhood) treated and followed up at the National Spinal Injuries Center (identified from case notes review, contacted and agreed to participate).

METHOD

One hundred and eighty-nine subjects satisfying study inclusion criteria (acute onset SCI before the 16th birthday) were identified by case note review of 8200 records. Eighty formed the group attending for clinical review including whole spine radiographs (AP and lateral). Clinical examination included neurological status and joint range of movements. Demographic data was recorded.

RESULTS

Scoliosis occurred more frequently and was more severe in those injured at a younger age, 38 degrees, compared with 24 degrees in those injured later (P<0.05), in paraplegia, 33 degrees, versus tetraplegia, 17 degrees, (P<0.01) and in complete, 36 degrees, versus incomplete lesions, 18 degrees, (P<0.001). Lordosis angulation in paraplegic subjects was significantly greater than in tetraplegic subjects in both seated, 50 degrees versus 25 degrees (P<0.014) and standing subjects 78 degrees versus 59 degrees (P<0.017) respectively and for kyphosis in standing subjects, 52 degrees versus 31 degrees (P<0.01). Sagittal measurements were influenced by habitual posture (which also corresponded to the severity of the lesion).

CONCLUSION

Younger age at onset was shown to be associated with more severe scoliosis, as has been reported by others. Subjects with paraplegia and complete lesions demonstrated a greater and more frequently occurring scoliosis than those with tetraplegia and incomplete lesions respectively. Lordosis was greater in those with paraplegia than with tetraplegia and in those with very incomplete lesions compared with complete lesions. However the influence of the severity of the lesion cannot be separated from the postural position when analyzing spinal deformity.

Areas of fat loss in overweight young females following an 8-week period of energy intake reduction

In order to investigate the main areas of fat loss after an 8-week period of energy intake reduction, the distribution of body fat was assessed on 14 females (BMI 27.3+/-0.83 kgm(-2)) (mean +/- SEM), aged 18-22 years. Total body fat was determined by hydrostatic weighing and subcutaneous fat mass and distribution were assessed using ultrasound and waist-hip circumference ratios prior to, and following, an 8-week period during which subjects attempted to reduce their energy intake by about 4.2 MJ day(-1). Subjects lost an average of 2.99+/-0.34 kg (p < 0.001), with greater loss (p < 0.001) of internal fat (1.5+/-0.2 kg) than of subcutaneous fat (0.7+/-0.1). Subjects reduced their waist-hip ratio from 0.771+/-0.01 to 0.762+/-0.01 (p < 0.01), their waist circumference from 807+/-24 to 790+/-23 mm (p < 0.001) and their hip circumference from 1047+/-29 to 1037+/-29 mm (p < 0.001). Those with an android distribution of fat (n = 5) lost more weight than those with gynoid distribution (n = 9) (3.80+/-0.38 kg vs 2.54+/-0.14 kg, p < 0.05); they also showed a greater decrease in waist circumference (27+/-5 vs 14+/-4 mm, p < 0.05) and a greater loss from internal fat stores (2.1+/-0.3 kg vs 1.1+/-0.2 kg, p < 0.05). The findings suggest that individuals are prone to lose internal fat during a short period of reduced energy intake. As the visceral fat store is the largest internal fat depot in the body, this suggests that individuals are indeed losing fat that could predispose to upper body obesity.

Anti-calculus activity of a toothpaste with microgranules

OBJECTIVE

The objective of the trial was to determine the efficacy of the proven anticalculus active system (zinc citrate trihydrate [ZCT] and triclosan), when the ZCT is delivered from microgranules incorporated in a silica-based toothpaste containing 1450 ppm F as sodium fluoride.

DESIGN

A monadic, single-blind, two phase design clinical trial was used to compare the effect of the test and a negative control fluoridated toothpaste on the formation of supragingival calculus.

SUBJECTS AND METHODS

Male and female calculus-forming volunteers, aged 18 or over, were recruited for the study following a 2-week screening phase. All subjects were given a scale and polish of their eight lower anterior teeth at the start of both the pre-test and test phases. Subjects were supplied with a silica-based 1450 F ppm fluoridated toothpaste with no anti-calculus active for use during an 8-week pre-test phase. Calculus was assessed at the end of the pre-test and test phases using the Volpe-Manhold index (VMI). Subjects were stratified according to their pre-test VMI score (8-10, 10.5-12, > 12) and gender and then allocated at random to test or negative control toothpaste groups. Subjects with < 8 mm of calculus were excluded from further participation.

MAIN OUTCOME MEASURE

The outcome variable was the mean VMI score for the test and negative control groups.

RESULTS

The test toothpaste caused a statistically significant 30% reduction in calculus compared with the control paste after a 13-week use. No adverse events were reported during the study.

CONCLUSION

The incorporation of the ZCT in microgranules did not adversely affect the anticalculus activity of the new formulation.

A three-year clinical trial of a combination of trimetaphosphate and sodium fluoride in silica toothpastes

The relative efficacy of NaF silica toothpastes containing 1000 ppm fluoride and 1500 ppm fluoride in the control of dental caries is not clear-cut. Also, it has not been established that incorporation of trimetaphosphate (TMP) improves the anticaries activity of NaF toothpastes. A three-year clinical trial was conducted to test the hypotheses that: (i) the anticaries activity of NaF toothpastes containing 1500 ppm F was greater than that of NaF toothpastes containing 1000 ppm F, and (ii) inclusion of TMP improved the efficacy of NaF silica pastes. Subsidiary aims included determination of whether frequency of toothbrushing and method of rinsing after brushing were correlated with caries increments. The study involved 4196 children aged 11 to 12 years at outset. These participants had been selected from a pool of 7374 potential subjects on the basis of caries experience and dental eruption pattern. They were stratified by sex, examiner, and presence of calculus and caries, and were allocated at random to one of the four toothpastes under study. Using mirror and probe and also FOTI, we carried out clinical examinations at baseline and annually thereafter for 3 yrs. Bitewing radiographs of a subset of children were taken at baseline and at the end of the study. The outcome measure for the study, DMFS increment, was defined as the increase in caries over 3 yrs, taking into account changes occurring on individual tooth surfaces. Data for 3467 subjects were available for analyses at both baseline and year 3 examinations. Radiographs were taken for 1942 subjects at both baseline and year 3 examinations. The mean three-year clinical-only DMFS increment for the subjects using 1500-ppm-NaF pastes was 3.93, which was 6% lower than the corresponding mean of 4.19 for the 1000-ppm-NaF pastes. There was no significant difference between the mean DMFS increment for those using paste with or without TMP. Subjects who claimed to brush more frequently or who claimed not to use a tumbler to rinse after toothbrushing had lower three-year DFMS increments.

Brisk walking reduces calcaneal bone loss in post-menopausal women

1. This study examined the influence of brisk walking on skeletal status in post-menopausal women. 2. Subjects were 84 healthy women aged 60-70 years. Who were previously sedentary and at least 5 years post-menopausal. Subjects were randomly assigned to walking (n = 43) and control (n = 41) groups. Walkers followed a 12-month, largely unsupervised programme of brisk walking. The bone mineral density of the lumbar spine, femoral neck and calcaneus and broadband ultrasonic attention of the calcaneus were measured at baseline and after 12 months. 3. Forty control subjects and 38 walkers completed the study. Walkers built up to 20.4 +/- 3.8 min/day (mean +/- SD) of brisk walking. Body mass increased in control subjects relative to walkers [mean change (SE) +0.9 (0.3) and -0.1 (0.3) kg respectively; P = 0.04]. Predicted maximum oxygen uptake increased in walkers by 2.1 (0.9) ml min-1 kg-1 (P = 0.02). Bone mineral density in the lumbar spine and calcaneus fell in control subjects [-0.005 (0.004) and -0.010 (0.004) g/cm2, respectively] but not in walkers [+0.006 (0.004) and +0.001 (0.004) g/cm2]. The difference in response between groups was significant in the calcaneus (P = 0.04) but not in the lumbar spine (P = 0.08). Mean femoral neck bone mineral density did not change significantly in either group, although changes in walkers were related to the amount of walking completed (r = 0.51, P = 0.001). The change in broadband ultrasonic attenuation of the calcaneus differed between groups [control subjects, -3.7 (0.8); walkers, -0.7 (0.8) dB/MHz; P = 0.01]. 4. Walking decreased bone loss in the calcaneus and possibly in the lumbar spine. It also improved functional capacity and enabled walkers to avoid the increase in body mass seen in control subjects.

Serum lidocaine concentrations after subcutaneous administration in patients undergoing cardiac catheterization in a pediatric institution

OBJECTIVE

We wished to determine serum lidocaine concentrations after subcutaneous injection during cardiac catheterization.

METHOD

Serum lidocaine concentrations were measured in 50 patients during catheterization.

RESULTS

Serum concentration was linearly related to dose per kilogram of body weight. Lidocaine concentrations were therapeutic in 38% of patients.

CONCLUSION

Lidocaine dose must be considered when the drug is used for local anesthesia in children.

Decision making in quasi-markets: a pedagogic analysis

The objective of the 1991 NHS reforms was to reduce "excessive" vertical integration by constructing a quasi-market in which incentive structures and increased availability of information would enable decision makers make better use of resources. There is, however, no overall framework in which to consider the welfare gains which result from the introduction of a quasi-market or the welfare losses which arise from distortions in a quasi-market. This paper offers an analysis which can be applied to illustrate the difficulty of estimating the welfare loss from cream skimming and also to consider the impact of local monopoly.

Problem-based learning in an undergraduate nursing programme: a case study

Over the past 15 years, the 'theory-practice gap' has been a recurrent theme in the nurse education literature. Numerous explanations are put forward for its existence, along with many suggestions as to how the apparent divide can be bridged. A key component of nursing practice is problem-solving but not all nurses are competent at finding suitable solutions to the problems they face in practice settings. Therefore ways of developing learner proficiency in problem-solving is crucial and should occupy a substantial part of teacher activity. One recent educational method for promoting problem-solving skills is problem-based learning [PBL] using the hypothetico-deductive technique. This approach encourages students to work through problem situations, generating hypotheses and testing these against the relevant literature and personal experience. The process itself is seen as the essential element in developing problem-solving skills, so that when the students are qualified they can apply the same methods to patient care. This paper explores the use of the PBL approach with a group of 11 fourth-year undergraduate students. The method employed was a case study design using observation as the main data collection technique. Subsequent analysis focused on: (a) practice; (b) teaching method; (c) knowledge attainment; and (d) the role of the teacher.

Pharmacokinetics of phenytoin in children with acute neurotrauma

OBJECTIVE

To determine the pharmacokinetics of intravenous phenytoin in critically ill infants and children with acute neurologic injury.

DESIGN

A prospective, descriptive study.

SETTING

A pediatric intensive care unit.

PATIENTS

Sixteen children, 0.5 to 16 yrs of age (mean 7.6), with various types of acute neurologic injuries, receiving intravenous phenytoin therapy.

INTERVENTIONS

Blood samples were collected to measure total and free phenytoin concentrations in plasma. A 24-hr urine collection was made to determine the concentrations of the major metabolite of phenytoin.

MEASUREMENTS AND MAIN RESULTS

In 12 children who survived the acute illness, a lower-than-predicted Michaelis-Menten constant (Km) and higher-than-predicted maximum rate of metabolism (Vmax) were observed. Initial free phenytoin fractions ranged between 0.08 and 0.15. In the eight patients who had additional free fractions measured, six patients demonstrated an increase (9.1% to 34% increase) in free fraction, while two patients demonstrated a decrease (1.8% and 19.8% decrease) in free fraction. The ratio of amount of phenytoin to phenytoin plus 5-(p-hydroxyphenyl)-5-phenylhydantoin excreted in the urine in a 24-hr urine collection demonstrated a wide inter-patient variability. There was no correlation in the difference between the predicted and calculated Km and Vmax values and Glasgow Coma Score, circulating albumin concentration, or concomitant medications.

CONCLUSION

Based on the average Km and Vmax values of the children enrolled in our study, it appears that children with neurologic injury between the ages of 0.5 and 9 yrs may require dosages of at least 8 to 10 mg/kg/day, and children aged 10 to 16 yrs may require 6 to 8 mg/kg/day to attain therapeutic phenytoin concentrations.

Cross sectional stature and weight reference curves for the UK, 1990

The current reference curves of stature and weight for the UK were first published in 1966 and have been used ever since despite increasing concern that they may not adequately describe the growth of present day British children. Using current data from seven sources new reference curves have been estimated from birth to 20 years for children in 1990. The great majority of the data are nationally representative. The analysis used Cole's LMS method and has produced efficient estimates of the conventional centiles and gives a good fit to the data. These curves differ from the currently used curves at key ages for both stature and weight. In view of the concerns expressed about the current curves and the differences between them and the new curves, it is proposed that the curves presented here should be adopted as the new UK reference curves.

Ultrasound and dual X-ray absorptiometry measurement of the calcaneus: influence of region of interest location

Ultrasound measurements of the calcaneus are related to incidence of osteoporotic fracture. Such measurements are generally made at fixed coordinates relative to a footplate. This study compares measurements at an anatomically located region of interest (ROIanat) and at fixed coordinates (ROIfixed), with bone mineral density measurements, in 84 postmenopausal women. Bone mineral density (BMD) was assessed using dual energy X-ray absorptiometry at both ROIs as well as at lumbar spine and femoral neck. Broadband ultrasound attenuation and velocity of sound were measured using a CUBA system at ROIanat and ROIfixed. Additionally, broadband ultrasound attenuation at ROIfixed was measured using a Walker Sonix instrument. Mean bone mineral density, broadband ultrasound attenuation and velocity of sound did not differ significantly between ROIfixed and ROIanat, although broadband ultrasound attenuation by Walker Sonix (81.4 +/- 14.6 dBMHz-1) was significantly (P < 0.001) greater than that by CUBA (63.7 +/- 14.2 dBMHz-1). The relationship between broadband ultrasound attenuation and BMD differed significantly between the 2 ROIs and the correlation of this relationship was significantly greater at ROIfixed than at ROIanat(r = 0.74 versus 0.46, P < 0.01). The differing relationship may reflect structural variation at different regions. ROI selection may thus be a possible confounding factor in ultrasound measurement.

Hindsight bias in reflective practice: an empirical investigation

Reflection is seen as a central component in the education and practice of nurses. It is through critical reflection on one's practice that expertise can be assured. This faith in the process of reflection has influenced much of pre and post registration nurse education. It is only in the past few years that reflection as a technique has being criticized. A small-scale study investigating the phenomenon of hindsight bias and its consequence on the reflective process is described. The effects of the hindsight bias is to influence people's recollection of events once they know the final outcome. The present study does indicate that nurses are susceptible to such a bias, which would question the validity of reflection as a way to enhance patient care. There is an urgent need to clarify the reflective process and then to examine its effect on patient outcomes.

The effect of standardising the body mass index for relative sitting height

The body mass index (BMI) has become a universal index of energy nutritional status in adults even though it is influenced by many factors other than energy stores. One of these is variation in height caused by variation in the length of the trunk and legs. Such variations occur between and within populations. In the British population, with a sitting height/stature (SH@S) ratio at the mode of population values, adjustment of BMI for SH/S ratio caused BMI to change by 1 kg/m2 or more in 33% of women and 10% of men and by 2 kg/m2 in 5% of women and 1% of men. The possible effects of shape, as evinced by SH/S ratios should be borne in mind when describing individuals or populations as overweight or obese in epidemiological studies and in decisions of clinical management.

Evaluation of near infra-red interactance for assessment of subcutaneous and total body fat

OBJECTIVE

Near infra-red interactance (NIRI) has been used for assessment of total body fatness, but its relationship with composition at the measurement site is not clear. This study examines the relationship of interactance with subcutaneous adipose tissue and muscle thickness as well as total body fat content.

DESIGN

(i) Validation of NIRI by comparison with subcutaneous tissue thicknesses from ultrasound. (ii) Cross-validation of techniques for estimation of body fat content.

SETTING

Laboratory.

SUBJECTS

(i) 54 young adults (27 male and 27 female) and (ii) 63 middle-aged men.

INTERVENTIONS

Measurements of subcutaneous adipose tissue thickness and muscle thickness using ultrasound, near infra-red interactance (Futrex 5000) and skinfold thicknesses were made at five sites in young adults. In middle-aged men total body fat was assessed by densitometry, NIRI and skinfold thickness. Measurements were made in duplicate by a single trained observer.

RESULTS

Interactance measurements were related to subcutaneous adipose tissue thickness, although the relationship varied according to measurement site r = 0.09 at anterior thigh to 0.78 at biceps; P = 0.31 to < 0.0001). Muscle thickness explained additional variance in interactance only at biceps in women. Subcutaneous adipose tissue thickness correlated better with skinfold thickness (r = 0.56 to 0.92; P = 0.002 to < 0.0001) than with interactance. Mean difference in fat mass from densitometry +/- 95% limits of agreement was -1.61 +/- 7.68 kg for NIRI and -2.84 +/- 6.56 kg for skinfold thickness in middle-aged men. NIRI tended to underestimate higher (and overestimate lower) levels of fatness.

CONCLUSIONS

NIRI performed no better than skinfolds in assessment of either subcutaneous or total body fat.

Prevalence of clinically apparent recurrent caries in Scottish adolescents, and the influence of oral hygiene practices

The prevalence of recurrent caries was recorded at the annual examinations of a 3-year double-blind caries clinical trial involving 4,294 children age 12-13 years at baseline. Recurrent caries was defined as clinically apparent disease affecting the restoration margins. Examination of all surfaces of undried teeth was carried out using a CPITN-C probe. The proportion of children with recurrent caries was 7.5, 9.5, 6.3 and 8.0% at baseline, year 1, year 2, and year 3. The proportions of restorations with recurrent caries was 1.9, 1.8, 1.0 and 1.1%, respectively, at each examination. A number of oral hygiene parameters were collected via a computer questionnaire. Water rinsing after brushing proved to be associated with recurrent caries (p < 0.01), those using a beaker having more recurrent caries than those using less diluting methods. Subjects who brushed twice a day (at the final examination) had less recurrent caries than those reporting to brush less often (p < 0.01). Both these results are consistent with previous findings on the association between DMFS increments and oral hygiene practices.

Reliability and repeatability of 3-D body scanner (LASS) measurements compared to anthropometry

The Loughborough Anthropometric Shadow Scanner (LASS) digitizes the body, to give size and shape in three dimensions. After some manipulation of data, body measurements can be taken from the computerized scan. This paper compares LASS measurements with anthropometric measurements, and examines intra- and inter-observer differences of both techniques. LASS and anthropometric measurements were generally similar. Although there were small but significant (p < 0.05) differences at some sites, these differences were explained by difficulties in making horizontal tape measurements, and by differences in site location on LASS scans due to imperfect site markers. Standard errors of measurement due to intra-observer differences were generally smaller by LASS (1.1-5.3 mm) than anthropometry (2.0-7.2 mm); however, inter-observer differences were similar by both techniques (3.0-13.1 mm for anthropometry compared to 1.3-8.3 mm for LASS). Repeatability of 3-D measurements taken from computerized whole-body scans was no better than that from traditional anthropometric measurements; however, the scan data have a far greater utilization, for they provide information on body shapes, segmental volumes and surface areas as well as size.

The influence of a 1-year programme of brisk walking on endurance fitness and body composition in previously sedentary men aged 42-59 years

This study examined the influence of a 1-year brisk walking programme on endurance fitness and the amount and distribution of body fat in a group of formerly sedentary men. Seventy-two males, aged 42-59 years, body mass index 25.2 (0.3) kg.m-2 [mean (SEM)], were randomly allocated to either a walking group (n = 48) or control group (n = 24). Brisk walking speed was evaluated using a 1.6-km track walk. Changes in endurance fitness were assessed by measuring blood lactate concentration and heart rate during submaximal treadmill walking. Body composition was determined by hydrostatic weighing and anthropometry; energy intake was assessed from 7-day weighed food inventories. Differences in the response of walkers and controls were examined using two-way analyses of variance. Forty-two walkers (87.5%) completed the study and averaged 27.9 (1.4%) min.day-1 of brisk walking (range 11-46). Brisk walking speed averaged 1.95 (0.03) m.s-1 and elicited approximately 68 (1) % of maximum heart rate. Heart rate and blood lactate concentration during submaximal treadmill walking were significantly reduced in the walkers after 3, 6 and 12 months and the oxygen uptake at a reference blood lactate concentration of 2 mmol.l-1 was increased by 3.2 ml.kg-1.min-1 (14.9%) in the walkers at 6 months (P < 0.01). Although skinfold thicknesses at anterior thigh and medial calf sites decreased significantly for the walkers, the response of the two groups did not differ significantly for other body composition variables or for energy intake.

Measurement of body surface area in children with liver disease by a novel three-dimensional body scanning device

Body surface area (BSA) is used in paediatrics to assess fluid requirement, drug doses, cardiac output and glomerular filtration rate. The aim of this study was to examine, in children with liver disease, the relationship between BSA determined by a traditional nomogram and BSA measured by a novel three-dimensional technique--Loughborough Anthropometric Shadow Scanner (LASS). Subjects were 16 children, mean age 8.1 (range 3.6-14.9) years, with a variety of liver diseases. Twenty-eight controls had a mean age of 7.1 (3.1-10.5) years. All had LASS scans performed as well as 21 anthropometric measurements taken by a single observer. There was a significant relationship between BSA (LASS) and BSA nomogram for liver-diseased children (r = 0.99) and controls (r = 0.96). The BSA nomogram values were significantly greater (P < 0.05) than BSA (LASS) for liver-diseased subjects by 10.1% (-0.35 to +20.6; 95% confidence interval), and for controls by 9.6% (4.1-23.2). Best prediction of BSA (LASS) for liver-disease subjects used height, body weight and gluteal furrow circumference [r2 = 0.997; standard estimated error (SEE) = 0.015 m2] and for controls used body weight alone (r2 = 0.907; SEE = 0.048 m2). BSA nomogram has no additional error in children with liver disease, but may overestimate BSA by 10% compared with a novel three-dimensional body surface scanning technique.

Brisk walking and serum lipoprotein variables in formerly sedentary men aged 42-59 years

1. The purpose of this study was to examine the influence of brisk walking on serum lipoprotein variables. 2. Seventy-two apparently healthy but physically inactive men (aged 42-59 years) were recruited. These men were normotensive non-smokers without a history of dyslipidaemia. Subjects were randomly allocated on a 2 to 1 basis into either a walking group (n = 48) or a control group (n = 24). Walkers followed a self-monitored programme of brisk walking for 1 year, whereas control subjects maintained their habitual lifestyle. 3. Treadmill walking tests were conducted to examine changes in fitness. Concentrations of serum lipids and lipoproteins were determined in fasting subjects. The amount of body fat was measured by body density. Circumferences at the waist and hip and skinfold thicknesses were used to determine the distribution of body fat. Dietary intakes were assessed by weighed food inventories. 4. Seven subjects (six walkers and one control subject) dropped out during the study. Walkers did an average of 28 (SEM 1.4; n = 42) min of brisk walking/day. This improved endurance fitness but did not influence serum concentrations of total cholesterol, high-density lipoprotein cholesterol, triacylglycerol, apolipoprotein A-1, apolipoprotein B or lipoprotein (a). Neither body mass nor the amount of body fat changed, relative to control subjects. 5. These data suggest that brisk walking does not modify lipoprotein metabolism in normolipidaemic middle-aged men.

Aseptic loosening of the femoral component in cemented total hip replacement

The purpose of this study was to identify factors which predispose to aseptic loosening of the femoral component in cemented total hip replacement. Its design was based on rigid selection criteria, so that successful and loose replacements which employed the same surgical technique were compared. Measurements of patient anatomy and of the insertion of the femoral component were made, by an accurate computer technique, on initial post-operative radiographs. Loosening was associated with heavier patients with a wider medullary canal which was flared proximally. This difference in anatomy led to differing distributions of cement in the successful and loose replacements. Medial cement-bone demarcation, at the mid-stem level, was also associated with loosening. These findings indicate the importance of optimizing the size of the prosthesis with respect to the femoral morphology.

Bending and fracture of the femoral component in cemented total hip replacement

A computer method was used to make 41 measurements on the geometry of insertion of the femoral component in 200 Charnley total hip replacements. Surgery had been performed at least 12 years before, giving results which were classified as: success (90); fracture (56); or loose (54), according to rigid selection criteria. Fracture was associated with heavier patients in which there was poor proximal fixation of the femoral component but adequate distal fixation. Stems with a medial disposition proximally were more common in the fracture group than in the successful or loose groups. Sequential measurements of bending and subsequent fracture were made on the follow-up radiographs of 24 of the 200 cases (6 fracture and 18 successful). These measurements allowed bending to be detected at an earlier stage than by simple inspection of the radiographs.

Brisk walking improves endurance fitness without changing body fatness in previously sedentary women

The purpose of this study was to examine the influence of brisk walking on endurance fitness and the amount and distribution of body fat in previously sedentary women. Twenty eight women [mean age (SEM): 44.9 (1.5) years] followed the walking programme for 1 year, whilst 16 acted as controls [age 44.4 (2.3) years]. Changes in endurance fitness were evaluated by measuring the oxygen uptake (VO2) at a reference blood lactate concentration of 2 mmol.l-1. Two 1.61-km field tests of walking were completed, one at maximal speed and one at a "brisk" speed, as well as a 1.61-km walk on a motorised treadmill. The amount and distribution of body fat was determined by hydrostatic weighing and anthropometry and energy intake was evaluated using the 7-day weighed food intake method. Walkers completed an average of 157 min.week-1 of brisk walking over the year. The following were increased in walkers, relative to controls: brisk walking speed [walkers 1.73 (0.05) m.s-1 vs 1.88 (0.07) m.s-1; controls 1.69 (0.05) m.s-1 vs 1.70 (0.05) m.s-1 at baseline and 12 months respectively, P < 0.01], maximal walking speed and VO2 at 2 mmol.l-1. In addition, brisk walking reduced heart rate and blood lactate concentration during stepping as well as during standard, submaximal treadmill walking. It did not modify either the amount or the distribution of body fat, despite an unchanged energy intake.

Measurement of hip prostheses using image analysis. The maxima hip technique

A computer-based image analysis system has been developed as a research tool in total hip replacement. The system has been programmed to take multiple measurements from coronal plane radiographs. Poor quality radiographic images can be enhanced and standardised. The measurements which can be obtained include stem subsidence, cup migration, cup wear, and stem loosening. Reproducibility and accuracy were +/- 0.01 mm and +/- 0.5 mm respectively. The present application is in retrospective research, but prospective monitoring of radiographs is planned.

Influence of brisk walking on the broadband ultrasonic attenuation of the calcaneus in previously sedentary women aged 30-61 years

The amount and type of exercise needed to maintain or increase bone density in women is unclear. The purpose of the present study was to examine the influence of brisk walking on broadband ultrasonic attenuation (BUA) values for the calcaneus in formerly sedentary women aged 30-61 years (mean 44). Twenty-five women followed the program of brisk walking for 1 year and 15 acted as controls. The walkers completed an average (SEM) of 159 (46) minutes/week of brisk walking at a speed of 1.72 (0.05) meters/second, i.e., about 16-18 km/week. Broadband ultrasonic attenuation was determined at baseline and after 1 year. Analysis of variance showed that values were increased (P less than 0.05) for the walkers relative to controls [walkers 103.3 (4.9) versus 116.1 (3.8) dB/MHz; controls 103.6 (5.5) versus 99.6 (5.4) dB/MHz]. We conclude that, in formerly sedentary women, a modest program of a widely acceptable form of exercise, brisk walking, can provoke an increase in this sensitive index of bone condition.

Effective pulmonary flow, aortic flow and cardiac output: in vitro and in vivo comparisons in the dog

This paper presents data on the measurement of aortic flow (Qa) using an electromagnetic flowmeter and the measurement of pulmonary blood flow (Qep) using a single-breath technique employing freon-22 as the soluble marker gas. The purpose was to assess the potential of a single-breath technique (using freon) as an effective way to estimate cardiac output (Q) non-invasively. The electromagnetic flowmeter was calibrated in vitro in an isolated heart-aorta preparation by collection of the ejected blood volume, thereby giving an absolute calibration of the Qa measurement. Using anaesthetized beagles Qa was measured immediately preceding (Qa,mean) and during (Qa,inst) measurement of Qep. These measurements were made before and after I.V. bolus doses of nifedipine used to increase cardiac output so as to measure a range of flows. The Qa was disturbed by the respiratory manoeuvre imposed as part of the single-breath technique, rising, falling and rising again as the lung volume was reduced, increasing with the test gas and reducing again, typically giving Qep = 1.39 +/- 0.13 l min-1, Qa,mean = 1.35 +/- 0.15 l min-1 and Qa,inst = 1.33 +/- 0.17 l min-1 (+/- S.D., n = 7 in each case). The standard deviations include interanimal variation as well as technique errors. Regression analysis of Qep on Qa,mean gave the highest correlation (r = 0.75) and the lowest coefficient of variation (11.7%), the values being 0.69 and 14.0% respectively for Qep on Qa,inst. These compare favourably with equivalent values for alternative methods reported in the literature, the strict calibration giving confidence that the single-breath technique provides data closely related to the aortic flow found prior to the respiratory manoeuvre, i.e. the undisturbed cardiac output.

Prosthetic hip failure: retrospective radiograph image analysis of the acetabular cup

A method has been developed for quantifying movement and wear of the acetabular component (cup) of total hip replacements (THR) from routine postoperative and review radiographs. The method uses both interactive and automatic computer image analysis techniques. Dimensions of the prosthesis are used to scale the measurements and so overcome variation in radiographic alignment. The application of the method is illustrated by retrospective investigations of cup migration and wear using review radiographs taken over a follow-up of at least 12 years.

Solubility of freon-22 in blood and lung tissue

Despite the frequent use of freon-22 (e.g. to measure pulmonary blood flow), there is no agreement on its solubility in water or body fluids. The values in the literature vary, often quoted without reference to measurement or identification as Ostwald or Bunsen coefficients. We used a Schölander apparatus and determined the Bunsen solubility coefficient (mlgas.(mlfluid.atmosphere)-1) at 37 degrees C as: 0.476 in water; 0.673 in human whole blood; 0.479 in human plasma; 0.662 in canine whole blood; 0.437 in canine plasma; and 1.077 in homogenized canine lung tissue. As pure freon was used, these solubilities may not be applicable if freon-22 does not obey Henry's law. In man, the Ostwald solubility coefficient is calculated as 0.76 ml/ml whole blood at BTPS. These results provide information for further studies involving freon-22, and clear the confusion which has arisen from poorly defined solubility coefficients.