Two years' experience with inspiration breath-hold in liver SBRT

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The workflow of inspiration breath-hold SBRT for liver metastases is described.

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Inspiration breath-hold in liver SBRT is feasible for 95% of the patients.

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An individual margin recipe for inspiration breath-hold liver SBRT is explained.

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Margin reduction of 10 mm using inspiration breath-hold compared to free breathing.

At-wavelength metrology facility for soft X-ray reflection optics

A new Optics Beamline coupled to a versatile UHV reflectometer is successfully operating at BESSY-II. It is used to carry out at-wavelength characterization and calibration of in-house produced gratings and novel nano-optical devices as well as mirrors and multilayer systems in the UV and XUV spectral region. This paper presents most recent commissioning data of the beamline and shows their correlation with initial beamline design calculations. Special attention is paid to beamline key parameters which determine the quality of the measurements such as high-order suppression and stray light behavior. The facility is open to user operation.

The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II

A technology center for the production of high-precision reflection gratings has been established. Within this project a new optics beamline and a versatile reflectometer for at-wavelength characterization of UV- and XUV-reflection gratings and other (nano-) optical elements has been set up at BESSY-II. The Plane Grating Monochromator beamline operated in collimated light (c-PGM) is equipped with an SX700 monochromator, of which the blazed gratings (600 and 1200 lines mm(-1)) have been recently exchanged for new ones of improved performance produced in-house. Over the operating range from 10 to 2000 eV this beamline has very high spectral purity achieved by (i) a four-mirror arrangement of different coatings which can be inserted into the beam at different angles and (ii) by absorber filters for high-order suppression. Stray light and scattered radiation is removed efficiently by double sets of in situ exchangeable apertures and slits. By use of in- and off-plane bending-magnet radiation the beamline can be adjusted to either linear or elliptical polarization. One of the main features of a novel 11-axes reflectometer is the possibility to incorporate real life-sized gratings. The samples are adjustable within six degrees of freedom by a newly developed UHV-tripod system carrying a load up to 4 kg, and the reflectivity can be measured between 0 and 90° incidence angle for both s- and p-polarization geometry. This novel powerful metrology facility has gone into operation recently and is now open for external users. First results on optical performance and measurements on multilayer gratings will be presented here.

Local progression and pseudo progression after single fraction or fractionated stereotactic radiotherapy for large brain metastases. A single centre study

PURPOSE

The 1-year local control rates after single-fraction stereotactic radiotherapy (SRT) for brain metastases > 3 cm diameter are less than 70%, but with fractionated SRT (FSRT) higher local control rates have been reported. The purpose of this study was to compare our treatment results with SRT and FSRT for large brain metastases.

MATERIALS AND METHODS

In two consecutive periods, 41 patients with 46 brain metastases received SRT with 1 fraction of 15 Gy, while 51 patients with 65 brain metastases received FSRT with 3 fractions of 8 Gy. We included patients with brain metastases with a planning target volume of > 13 cm(3) or metastases in the brainstem.

RESULTS

The minimum follow-up of patients still alive was 22 months. Comparing 1 fraction of 15 Gy  with 3 fractions of 8 Gy, the 1-year rates of freedom from any local progression (54% and 61%, p = 0.93) and pseudo progression (85% and 75%, p = 0.25) were not significantly different. Overall survival rates were also not different.

CONCLUSION

The 1-year local progression and pseudo progression rates after 1 fraction of 15 Gy or 3 fractions of 8 Gy for large brain metastases and metastases in the brainstem are similar. For better local control rates, FSRT schemes with a higher biological equivalent dose may be necessary.

Indications for cone-beam computed tomography in the area of oral and maxillofacial surgery

The aim of this study was to identify specific indications for dental cone-beam computed tomography (CBCT) in the field of oral and maxillofacial surgery. To this end, we compared the efficacy of CBCT to that of panoramic radiography, the standard imaging modality, for the evaluation of different surgical questions in the oral and maxillofacial region. Dentall CBCT proved to be particularly useful in cases where visualization of a second plane is necessary for implant planning or for pre-surgical evaluation of retained and displaced teeth posing a risk to adjacent structures. It is also indicated for precise localization of luxated teeth and dental implants dislocated into surrounding areas, localization of the mandibular canal to assess its anatomical relationship to overfilled root canal filling materials, assessment ofthe extent of osseous lesions, and evaluation of patients with suspected mandibular or condylar fractures. The main advantages of CBCT are reduction of the risks of surgery due to the free selection of imaging planes, maindibular canal marking, 1:1 magnification, and the ability to use DICOM data in other implant or surgical planning software. Adequate user experience is important for proper evaluation of dental CBCT scans, as is the diagnosis of incidental findings falling into areas not primarily related to dentistry and therefore requiring additional investigation.

Validation of air-displacement plethysmography for estimation of body fat mass in healthy elderly subjects

BACKGROUND

Air-displacement plethysmography (ADP) is a non-invasive method for body composition analysis that divides the body into fat-free mass (FFM) and fat mass (FM) (= 2 compartment model, 2C). It places low demands on subject performance and is therefore most convenient in the elderly.

OBJECTIVE

To validate ADP against dual energy X-ray absorptiometry (DEXA) and to compare it to a four-compartment model of body composition (4C; fat mass, total body water, bone mineral content and residual mass) in the elderly.

METHODS

Body composition was assessed by ADP, DEXA and bioelectrical impedance analysis (BIA) in 26 healthy elderly subjects (15 women, 11 men) aged 60-82 years.

RESULTS

Despite a high correlation of %FM assessed by ADP and DEXA we observed significant differences between the results of these methods for both sexes (2.5 +/-3.4%; bias +/- SD). Deviations of %FM(ADP) from %FM(DEXA) were dependent on bone mineral content (BMC(DEXA)) fraction of FFM. A low BMC(DEXA) was related to an overestimation of DEXA-derived %FM by ADP. There was a systematic bias between results from ADP and the 4C model. 76% of its variance was explained by the assumption of a fixed density of FFM. 96% of the variance in the density of FFM was explained by water content and only 4% by BMC(DEXA) of FFM. When compared to a 4C model, overestimation of %FM(ADP) increases with increasing water fraction of FFM.

CONCLUSION

Although there is a tendency for overestimation of %FM(ADP),ADP is a valid method for body composition measurement in the elderly. The bias in %FM(ADP) is mainly related to water content of FFM and indicates that a correction factor for TBW may improve the accuracy of the ADP measurements in the elderly.

Severe underreporting of energy intake in normal weight subjects: use of an appropriate standard and relation to restrained eating

OBJECTIVE

To assess the influence of different standards and restrained eating on underreporting in healthy, non-obese, weight-stable young subjects.

DESIGN AND SUBJECTS

Eighty-three young adults (20-38 years, 55 women, 28 men) were assessed under weight-stable conditions with a 7-day dietary record and the three-factor eating questionnaire by Stunkard and Messick. Resting energy expenditure (REE; indirect calorimetry) plus data derived from physical activity records (PA) (Standard 1) or REE times an activity factor (AF) (Standard 2) was used as standard for total energy expenditure (TEE). For comparison, doubly labelled water (DLW) was used to measure TEE in a subgroup of subjects.

RESULTS

There was an association between self-reported energy intake and Standard 2 but not with Standard 1. When compared with DLW both calculated standards were inaccurate, but Standard 2 avoided high levels of overreporting. Using Standard 2 to identify 'severe' underreporting (SU; as defined by a deviation of energy intake (EI) and TEE of >20%), SU was seen in 37% of all subjects. It was more frequently found in women than in men (49% of women, 14.3% of men, ). Underreporting subjects had a reduced EI but there were no significant differences in nutritional status (body weight and height, body mass index, fat mass and fat-free mass), energy expenditure and the proportion of energy from macronutrients between normal and underreporting subjects. However, high restraint was associated with a higher degree of underreporting in the total group, whereas disinhibition had an influence only in men.

CONCLUSIONS

A high prevalence of SU is seen in non-obese subjects. Characteristics of eating behaviour (restraint and disinhibition) were associated with underreporting but seemed to have a different influence in men and women.

Use of BMI as a measure of overweight and obesity in a field study on 5-7 year old children

OBJECTIVE

The present field study examines the use of BMI in comparison with estimates of percent fat mass to screen for overweight and obesity in children.

DESIGN

Cross-sectional field study.

SETTING

Four waves of children 1996-1999 at Kiel, North West Germany.

SUBJECTS

A representative large sample of 2,286 5-7 year old children representing 40% of the total child population examined by school physicians within the same period in Kiel.

MAIN OUTCOME MEASURES

BMI was compared with anthropometric measures (TSF, BSF, SIF, SSF) and bioelectrical impedance analysis (BIA). The 90th and 97th BMI percentiles were used as cut offs for overweight and obesity, respectively.

RESULTS

BMI reached a low sensitivity to identify overweight children when compared with the two estimates of % FM (0.60 to 0.78 for girls, 0.71 to 0.82 for boys, respectively). The specificity of BMI was 93 to 95 %. By contrast, BMI reached higher sensitivity to screen for obese children of 0.83 to 0.85 for boys and 0.62 to 0.80 for girls at a concomitant specificity of 0.95 to 0.98 for boys and 0.96 to 0.97 for girls as defined by assessment of body fat mass. Comparing nutritional status of overweight children classified as overweight or non overweight by BMI shows that BMI only identified obese but not-overweight children.

CONCLUSION

BMI can be used to screen for obese children. In contrast BMI has a poor sensitivity to screen for overweight children. Body composition analysis should be used to screen for children at risk of becoming obese.

Social class differences in overweight of prepubertal children in northwest Germany

OBJECTIVES

To assess social class differences in overweight and health-related behaviours in 5-7-y-old German children.

DESIGN

Cross-sectional study.

SETTING

Twenty-nine primary schools in Kiel (inhabitants: 248000), northwest Germany.

SUBJECTS

A total of 1350 German 5-7-y-old children and their parents.

MAIN OUTCOME MEASURES

Body mass index (BMI), fat mass and health-related behaviours of the children. Self-reported height and weight of their parents, parental school education as a measure of social class.

RESULTS

The prevalence of overweight (> or = 90th percentile of reference) was 18.5%. There was an inverse social gradient (P < 0.01): the highest fat mass was observed in children from low social class. The odds ratios for overweight reached 3.1 (CI 1.7-5.4) in boys and 2.3 (CI 1.2-4.3) in girls, respectively (low vs high social class). Overweight parents (BMI > or = 25 kg/m2) were more likely to have overweight children. Parental overweight enhanced the inverse social gradient. The prevalence of overweight was 37.5% (low social class) vs 22.9% (high social class) in children from overweight parents, respectively. There was an inverse social gradient in unhealthy behaviours. Parental BMI and physical inactivity were independent risk factors of overweight in children.

CONCLUSIONS

In 5 to 7-y-old children overweight and health-related behaviours are inversely related to social class. Parental overweight enhanced the risk of childhood overweight. The familial effect on body weight is most pronounced in children with low social class. Preventive measures should specifically tackle 'overweight families' from low social class.

[Problems in defining obesity in prepubescent children: consequences for assessing the requirements for medical rehabilitation]

INTRODUCTION

Prevalence of obesity has been on the increase in recent years. In contrast to obesity in adulthood, childhood obesity is still not uniformly defined. This results in problems to determine the need for medical rehabilitation.

METHODS

The Kiel Obesity Prevention Study (KOPS) is a cross-sectional study assessing the nutritional status of 5-7 year-old German children. Three different definitions of overweight and obesity (German reference data for triceps skinfold thickness [90(th) percentile] and BMI [90(th)/97(th) percentile] as well as an international standard for BMI [extrapolated to levels of adults]) were applied to 1,643 children of KOPS enrolled between 1996 and 2000 (19 % of all first-graders in Kiel in this period).

RESULTS

The prevalence of overweight varies from 9 to 21 % depending on the applied definition. With the definitions of overweight and obesity based on newer BMI percentiles a part of overweight children are not classified as such. The present state of art is that there is only a need for obese children for medical rehabilitation: these are 3.3 and 3.5 % of 5-7 year-old children in Kiel, respectively.

CONCLUSIONS

Experts should work out an agreement concerning a uniform definition of childhood obesity. Currently, medical rehabilitation services are offered only to extremely obese children. There is a need for more and earlier preventive measures.

[WHO warns of obesity epidemic. Are we becoming a society of obese persons?]

Overweight and obesity, together with their concomitant diseases and sequelae, have reached epidemic proportions. The problem is therefore not merely personal, but also societal. We have become an overweight society on its way to obesity. What we need is effective treatment over the long-term and a public health strategy to combat the condition. These two strategies are complementary, not in competition with each other. Without the latter, the successes of the former remain limited. We require national campaigns involving various aspects of our society aimed at promoting health and preventing disease. This makes necessary the involvement of politicians and representatives of various interested groups with appropriate responsibility. Members of health-related occupations should take the lead in initiating and maintaining such action.

Characterization of key residues in the subdomain encoded by exons 8 and 9 of human inducible nitric oxide synthase: a critical role for Asp-280 in substrate binding and subunit interactions

Human inducible nitric oxide synthase (iNOS) is active as a dimer of two identical subunits. Each subunit has an amino-terminal oxygenase domain that binds the substrate l-Arg and the cofactors heme and tetrahydrobiopterin and a carboxyl-terminal reductase domain that binds FMN, FAD, and NADPH. We previously demonstrated that a subdomain in the oxygenase domain encoded by exons 8 and 9 is important for dimer formation and NO synthesis. Further, we identified Trp-260, Asn-261, Tyr-267, and Asp-280 as key residues in that subdomain. In this study, using an Escherichia coli expression system, we produced, purified, and characterized wild-type iNOS and iNOS-Ala mutants. Using H(2)O(2)-supported oxidation of N(omega)-hydroxy-l-Arg, we demonstrate that the iNOS mutants' inabilities to synthesize NO are due to selective defects in the oxygenase domain activity. Detailed characterization of the Asp-280-Ala mutant revealed that it retains a functional reductase domain, as measured by its ability to reduce cytochrome c. Gel permeation chromatography confirmed that the Asp-280-Ala mutant exists as a dimer, but, in contrast to wild-type iNOS, urea-generated monomers of the mutant fail to reassociate into dimers when incubated with l-Arg and tetrahydrobiopterin, suggesting inadequate subunit interaction. Spectral analysis reveals that the Asp-280-Ala mutant does not bind l-Arg. This indicates that, in addition to dimerization, proper subunit interaction is required for substrate binding. These data, by defining a critical role for Asp-280 in substrate binding and subunit interactions, give insights into the mechanisms of regulation of iNOS activity.

Prevention of obesity--more than an intention. Concept and first results of the Kiel Obesity Prevention Study (KOPS)

OBJECTIVE

Obesity prevention is necessary to address the steady rise in the prevalence of obesity. Although all experts agree that obesity prevention has high priority there is almost no research in this area. The effectiveness of different intervention strategies is not well documented. There is also no structured framework for obesity prevention.

DESIGN

Based on (i) our current and limited knowledge and (ii) the idea that prevention of childhood obesity is an effective treatment of adult obesity, the Kiel Obesity Prevention Study (KOPS) was started in 1996. Concept, intervention strategies and first results of KOPS are reported in this paper. KOPS is an ongoing 8 y follow-up study. We first enrolled a large scale cohort of 5 to 7-y-old children, providing sufficient baseline data. KOPS allows further analyses of the role of individual risk factors as well as of long-term effectiveness of different intervention strategies.

RESULTS

From 1996 to 1999 a representative group of 2440 5 to 7-y-old children was recruited (ie 30.2% of the total population of 5 to 7-y-old children examined by the school physicians) and a full data set was obtained from 1640 children. Of the children, 340 (20.7%) were considered as overweight and obese, 1108 children (67.6%) were normal weight, and underweight was found in 192 children (11.7%). Of the normal-weight children, 31% or 346 (21.1% of the total population) were considered to have a risk of becoming obese. Cross-sectional data provided evidence that (i) there is an inverse social gradient in childhood overweight as well as health-related behaviours and (ii) parental fatness had a strong influence on childhood overweight. We observed considerable changes in health-related behaviours within 1 y after combined "school-" and "family-based" interventions. Interventions aimed to improve health-related behaviours had significant effects on the age-dependent increases in median triceps skinfolds of the whole group (from 10.9 to 11.3 mm in "intervention schools" vs from 10.7 to 13.0 mm in "control schools", P<0.01) as well as in percentage fat mass of overweight children (increase by 3.6 vs 0.4% per year without and with intervention, respectively; P<0.05).

CONCLUSION

First results of KOPS are promising. Besides health promotion, a better school education and social support seem to be promising strategies for future interventions.

Prevention of obesity--is it possible?

Obesity prevention is necessary to address the steady rise in the prevalence of obesity. Although all experts agree that obesity prevention has high priority there is almost no research in this area. There is also no structured framework for obesity prevention. The effectiveness of different intervention strategies is not well documented. Regarding universal prevention little rigorous evaluation has been carried out in larger populations. Obesity prevention has been integrated into community-wide programmes preventing coronary heart disease. Although effective with respect to reduction in cardiovascular risk factors these programmes did not affect mean body mass index (BMI) of the target populations. Selective prevention directed at high risk individuals (e.g. at children with obese parents) exhibited various degrees of effectiveness. However, at present, definitive statements cannot be made because of the limited number of studies as well as limits in study design. Finally, targeted prevention produced promising results in obese children when compared to no treatment. However, there are only very few longterm follow-up data. There is no clear idea about comprehensive interventions studying combinations of different strategies. It is tempting to speculate that predictors of treatment outcome (e.g. psychological and sociodemographic factors) may also serve as barriers to preventive strategies, but this has not yet been investigated. Taken together, obesity prevention should become a high priority research goal. First results of obesity prevention programmes are promising. As well as health promotion and counselling, better school education and social support appear to be promising strategies for future interventions.

Physical activity and diet in 5 to 7 years old children

OBJECTIVE

To assess the possible associations between physical activity, diet, social state and overweight in children.

DESIGN

Cross-sectional study on 1468 children aged between 5 and 7 years old in Kiel, northwest Germany.

METHODS

Assessment of physical activity and social factors by a questionnaire, food frequency record, body composition analysis by anthropometrics and bioelectrical impedance analysis.

RESULTS

23% of our children were overweight or obese. Low levels of physical activity (as assessed by TV viewing time) were associated with increased body mass index and a higher prevalence of overweight. TV-viewing of more than 1 h per day was associated with a high consumption fast food, sweets, chips and pizza whereas fruits and vegetables were less frequently consumed. Overweight, inactivity and unhealthy eating habits were seen more frequently in families with a low social status.

CONCLUSIONS

In 5 to 7 years old children, overweight is associated with physical inactivity, unhealthy eating habits and a low social status. Primary prevention efforts should be directed to low income families.

Gender differences in fat mass of 5-7-year old children

OBJECTIVE

Studying gender differences in fat mass and distribution in a homogeneous group of children.

DESIGN

Cross-sectional study.

SUBJECTS

610 children aged 5-7 y in Kiel, Germany.

METHODS

Anthropometric measures, bioelectrical impedance analysis (BIA).

RESULTS

Although boys had increased body weights (P<0.05), body mass indexes (BMI's) (P<0.001) and waist/hip ratios (WHRs) (P<0.001), the %fat mass as assessed by BIA (P<0.05) was increased in girls. Although the increased BMI in boys was independent of the percentile used, gender differences (that is, lower values for boys than for girls at the same age) in WHR, the sum of four skinfolds and %fat were seen up to the 90th percentile. By contrast, above the 90th percentile there were no differences in skinfold thickness and %fat between boys and girls. Studying 42 BMI-matched pairs (boys and girls) also showed that the %fat estimated by BIA (P<0.001) was increased in girls. Plotting the average of %fat as obtained from skinfold- and BAI-measurements against the difference between data obtained by the use of the two methods shows that BIA %fat overestimates skinfold %fat at low or normal percent fat mass (that is, up to 20%) in both genders. By contrast, at increased fat mass, BIA %fat seems to underestimate skinfold %fat in both genders.

CONCLUSIONS

Gender differences in fat mass and fat distribution are obvious in children aged 5-7 y. These differences are independent of gender differences in body weight. However, the nutritional state has an influence and gender differences cannot be detected in overweight and obese children. Our data also suggest that a children-specific formula used to calculate %fat from skinfold measurements is inappropriate.

Dietary underreporting: validity of dietary measurements of energy intake using a 7-day dietary record and a diet history in non-obese subjects

Substantial dietary underreporting questions the validity of dietary measurements of energy intake (EI). The present study compares the value of a 7-day prospective dietary record (7dDR) with a computer program-based diet history (DH). 7dDR and DH were performed in 50 non-obese subjects (33 females, 17 males, mean age 26.1 years, BMI 18.9-29.6 kg/m2) using total energy expenditure (EE = sum of resting metabolic rate as measured by indirect calorimetry plus energy expenditure derived from an activity protocol) as standard for the validity of data on EI. EI was 2,206 (728-3,646) kcal/day for 7dDR and 2,398 (566-4,764) kcal/day for DH. There was an association between EI for 7dDR and EI for DH (r = 0.6, p < 0.0001). Underreporting [i.e. a difference between EI and EE (delta E = EI - EE)] of 20% or more was seen in 48% (7dDR, mean -1,047 kcal/day, range -616 to -1,895, or -38.8% of EE) or 48% (DH, -1,151 kcal/day, -594 to -2,057 kcal/day, or -42.3% of EE). Considerable differences were found between delta E for 7dDR and delta E for DH (mean 603, range 26-2,033 kcal/day), and only 34% of underreporting subjects were identified by both dietary measurements. It is concluded that at the individual level dietary underreporting is influenced by the dietary assessment tool.