Experimental disease models for the assessment of meningococcal vaccines

Animal infection models are valuable for the development and preclinical assessment of meningococcal vaccines in the absence of clear in vitro correlates of protection for protein-based serogroup B vaccines. It is only in animal models that interactions of the organism with the innate, humoral and cellular immune systems can be assessed. However, humans are the only natural host for Neisseria meningitidis and there is no ideal disease model using laboratory animals that mimics the course of human disease. The two most widely used models are intraperitoneal (i.p.) infection of adult mice or infant rats. The mouse i.p. infection model requires an exogenous iron source (e.g. human transferrin) to obtain a lethal bacteraemic infection and can be used to assess both active and passive immunisation. The virulence of wild-type and knockout mutants can also be compared. i.p. infection of infant rats has been used to assess passive protection provided by sera raised against vaccine candidates or human vaccine sera. However, the duration of bacteraemia is short, mortality is low and active protection cannot be assessed. Recent developments using transgenic mice expressing human CD46 give hope that improved models will be developed.

Leptin, but not adiponectin, predicts stroke in males

OBJECTIVE

To test whether leptin and adiponectin are risk markers for a first-ever stroke. RESEARCH DESIGN, METHODS AND SUBJECTS: A nested case-referent study identified 276 cases with first-ever stroke (234 cases with ischaemic and 42 with haemorrhagic stroke). Prior to the stroke, they had participated in population-based health surveys in northern Sweden (median time between survey and stroke was 4.9 years). Referents were matched for sex, age, date and type of health survey, and geographical region. Putative risk markers for first-ever stroke, including blood pressure (BP), diabetes, smoking, body mass index (BMI), cholesterol, leptin, and adiponectin, were analysed by conditional logistic regression analysis.

RESULTS

Increased BMI, high cholesterol and fasting glucose levels, diabetes mellitus and hypertension were found in future stroke patients. Whereas leptin levels were higher in male subjects (P = 0.004), adiponectin did not differ between groups. A high leptin level independently predicted stroke in men (OR = 2.46; 95% CI 1.08-5.62) but not in women. Adiponectin levels did not predict stroke. Males with high leptin levels developed stroke faster than males with low leptin levels (P = 0.0009), independently of traditional risk factors.

CONCLUSIONS

Leptin may be an important link to the development of cerebrovascular disease in men, whereas adiponectin does not associate with future stroke.

Disparities in food habits in Europe: systematic review of educational and occupational differences in the intake of fat

BACKGROUND

A higher socio-economic level is associated with healthier dietary habits. Nevertheless, socio-economic differences in the intake of fat have not consistently been reported in Europe. The objective of our study was to systematically assess differences in total fat (TF) intake and saturated fat (SF) intake across social groups.

METHODS

Representative samples from nine European countries were used to perform a meta-analysis of surveys between 1985-1999, including both published and nonpublished results.

RESULTS

Because important heterogeneity was found and the estimates for TF from Spain and Estonia were different from all others, we calculated the differences in intake excluding these two countries. We found a lower TF intake in the highest (versus the lowest) occupational level both for men (difference: -1.1% of total energy intake; 95% CI: -1.3 to -0.8%) and women (difference: -0.9%; 95% CI: -1.2 to -0.6%) when Estonia and Spain were excluded.

CONCLUSION

European surveys indicate that people in the lowest category of occupation consume more fat and SF than people in the highest category.

Adult day care for dementia: a comparison of programs in Sweden and the United States

Adult day care is regarded as an important respite service to family caregivers of dementia patients to assist the patient to remain in the community. This study includes 178 Swedish and 86 American day care centers serving cognitively impaired clients. Client, staff and organizational characteristics were surveyed. Although the two countries have quite different systems of elder care, client characteristics were similar, suggesting that adult day care centers are a convergent solution to a common problem of supporting disabled elderly. Differences were found between the USA and Sweden in the staff, structure, and services of the programs. The study raises questions about day care centers' goals and organization. Results provide a clearer understanding of the optimal role and function of adult day care centers.

Clinical relevance of nasal polyps in individuals recruited from a general population-based study

OBJECTIVE

To compare the clinical presentations of individuals with nasal polyps detected by endoscopy in a general population sample with those of patients with nasal polyp disease seeking medical attention.

MATERIAL AND METHODS

A total of 38 individuals with nasal polyps from a population-based sample were compared with 38 matched controls and a third group consisting of 44 patients who presented to an outpatient clinic with symptoms and diagnosed nasal polyps Upper and lower airway symptoms were registered. Polyp size, peak nasal inspiratory flow (PNIF), olfactory function and health-related quality of life were measured.

RESULTS

Compared with the individuals with nasal polyps in the population sample, patients actively seeking medical care for nasal polyposis experienced more symptoms of nasal blockage and an impaired sense of smell, and had more extensive polyps and reduced PNIF. There were equal frequencies of asthma symptoms in these two groups. Compared with the controls, the individuals with nasal polyps in the population sample had a greater frequency of asthma symptoms and aspirin intolerance and also experienced an impaired sense of smell.

CONCLUSION

Nasal polyps alone, as seen occasionally, are indicative of airway disease involving the upper and lower respiratory tracts.

Biokinetics of iodide in man: refinement of current ICRP dosimetry models

A compartmental model describing the distribution and retention of radioactive iodide in thyroid and other organs is presented. The model is developed from published ICRP models. It is designed primarily for radiation dosimetry of iodine radionuclides used in nuclear medicine, but may also be useful for occupational radiation protection. In the proposed model, the distribution of iodide to the thyroid is assumed to be more rapid than in earlier models. Uptakes in stomach wall and salivary glands are considered, and the absorbed doses to these organs calculated. The partitioning of iodide between stomach wall and content is also discussed. Recirculation of organic iodine is also taken into account. Age-dependent half-times for iodide in the thyroid, as well as for organically-bound iodine are presented. The proposed model is applicable for dose estimations with different uptakes in the thyroid as well as for the situation when the thyroid is blocked, completely or incompletely.

The importance of adjusting for differences in proximal and distal contrast bolus arrival times in contrast-enhanced iliac artery magnetic resonance angiography

We tested the hypothesis that differences in proximal and distal contrast bolus arrival times may result in insufficient vascular signal in the distal part of the aortoiliofemoral territory with routinely used timing techniques. The difference in arrival time of the contrast medium bolus between the aorta and the common femoral arteries was measured in 14 patients undergoing magnetic resonance angiography of the aortoiliac arteries. A dual-station test bolus technique adjusting for this difference was evaluated. The variation coefficient of the signal intensity in six defined locations and signal intensities (SI) normalised to fat were calculated. Comparisons were made with findings in 13 patients examined with a fluoroscopically triggered timing technique (BolusTrak, Philips Medical Systems, Best, The Netherlands). The difference in bolus arrival time between proximal and distal vessels was 0-7 s. In 3 of 14 patients it was 5.6-7 s. There was a tendency towards a lower mean variation coefficient in the dual-station group ( p=0.10). With both techniques, significantly lower SIs were measured in the femoral arteries compared with SIs in the superior part of the abdominal aorta. In two cases in the BolusTrak group, a distal vessel could not be delineated but was shown to be patent on a delayed scan. Differences in contrast medium arrival time along the vessel may be large enough to preclude visualisation of distal vessels unless there is compensation. A dual-station test bolus technique taking this into account was found to be feasible.

A method for attenuation and scatter correction of brain SPECT based on computed tomography images

A method for attenuation and scatter correction of brain single photon emission computed tomography (SPECT) is described where computed tomography (CT) images of the brain are used for the calculation of attenuation maps. The method is evaluated for the substance 99mTc hexamethylpropylene amine oxime. A transmission dependent scatter correction is utilized and is based on ray sums calculated through the attenuation map. A method based on external markers is used to align the SPECT and CT image volumes. The markers need only to be present during the SPECT acquisition since the corresponding landmarks can be found without markers on the CT images. The mismatching has been investigated for five patients who have undergone both a CT examination and a SPECT examination with markers. Twelve individuals from the staff have pointed out the landmarks on the CT images, with an average standard deviation of 3.4 mm. Reconstructions with an attenuation map shifted the corresponding 95% confidence interval have been performed to obtain an estimation of the quantitative uncertainty caused by the mismatching, and quantitative errors of up to 6.3% have been measured. At present the method is probably most useful when groups of patients are studied.

A generic model for 11C labelled radiopharmaceuticals for imaging receptors in the human brain

A large number of radiopharmaceuticals labelled with 11C (half-time 0.340 h) are being developed for positron emission tomographic studies of different types of receptor in the human brain. For most of these agents, the available biokinetic data are insufficient to construct realistic compound-specific biokinetic models for calculating the internal radiation dose delivered to persons undergoing investigation. A generic model for brain receptor substances that predicts the internal dose with sufficient accuracy for general radiation protection purposes has, therefore, been developed. Biokinetic data for 13 11C-radiopharmaceuticals used clinically for imaging different brain receptors indicate that, despite differences in chemical structure, their uptake and retention in the human brain and other tissues are broadly similar. The proposed model assumes instantaneous deposition of 5% of the injected radioactivity in the brain, with the remaining radioactivity being rapidly and uniformly distributed throughout all other tissues. Elimination from all tissues is assumed to occur with a half-time of 2 h. It is further assumed that 75% of the injected 11C is excreted in the urine, and 25% via the gall bladder, with a half-time of 2 h. This model yields an effective dose of 4.5 x 10(-3) mSv MBq(-1), with doses of 3.2 x 10(-2), 1.7 x 10(-2), 8.7 x 10(-3), 5.2 x 10(-3), and 3.8 x 10(-3) mGy MBq(-1) to the urinary bladder, gall bladder, kidneys, brain and ovaries, respectively. These doses are well within the range of those reported using compound-specific models for the radiopharmaceutals studied.

Apoptosis in HeLa Hep2 cells is induced by low-dose, low-dose-rate radiation

Radioimmunotherapy with radiolabeled antibodies may cause inhibition of the growth of epithelial tumors, despite low total radiation doses and comparatively low radiosensitivity of epithelial tumor cells. The induction of apoptosis by low-dose radiation, such as delivered in radioimmunotherapy, was investigated in vitro in human HeLa Hep2 carcinoma cells. The cultured cells were exposed to defined radiation doses from a (60)Co radiation therapy source. The radiation source delivered 0.80 +/- 0.032 (mean +/- SD) Gy/min and the cells were given total doses of 1, 2, 5, 10 and 15 Gy. Using fluorescein-labeled Annexin V, followed by flow cytometry and DNA ladder analysis, apoptotic cells were detected and quantified. Radiation doses below 2 Gy did not cause any significant increase in apoptosis. Compared to control cells, apoptosis was pronounced after 5-10 Gy irradiation and was correlated to the radiation dose, with up to 42 +/- 3.5% of the cells examined displaying apoptosis. Clonogenic assays confirmed significantly decreased viability of the cells in the interval 2 to 10 Gy with low-dose-rate radiation, 60 +/- 2% compared to 2 +/- 2%. Lethal effects on the tumor cells were also evaluated by an assay of the cytotoxic effects of the release of (51)Cr. Significant cytotoxicity, with up to 64 +/- 6% dead cells, was observed at 5 Gy. Similar results were obtained when the dose rate was reduced to 0.072 +/- 0.003 Gy/min (mean +/- SD). In the case of the (137)Cs source, the dose rate could be reduced to 0.045 Gy/h, a level comparable to radioimmunotherapy, which induced significant apoptosis, and was most pronounced at 72-168 h postirradiation. It can be concluded that in vitro low-dose and low-dose-rate radiation induces apoptosis in epithelial HeLa Hep2 cells and thus may explain a mechanism by which pronounced inhibition of growth of HeLa Hep2 tumors at doses used in radioimmunotherapy has been obtained previously.

Rationale and methods of the EFCOSUM project

OBJECTIVE

To describe the rationale and methods for a European project (EFCOSUM) to develop a method for a European food consumption survey that delivers internationally comparable data on a set of policy-relevant nutritional indicators.

RATIONALE AND METHODS

Currently Member States are collecting data and information for use at national level. At an international level, such data are often of limited comparability and of varying quality. To promote the development and exchange of adequate, reliable and comparable indicators of public health, and the structures needed to exchange the relevant data, a programme of Community action on health monitoring was set up for the EU. The objective of the action programme is to contribute to the establishment of a Community Health Monitoring System. Data will be made available to all Member States via a telematic network, which is currently being developed for the Health Monitoring Programme. With regard to nutrition, there is a need for a limited set of policy-relevant dietary indicators that are comparable among EU Member States. In the field of nutrition, however, there is a regrettable lack of internationally comparable data. The project 'European Food Consumption Survey Method' (EFCOSUM) therefore aimed to define a (minimum) set of dietary components which are relevant determinants of health and to define a method for the monitoring of food consumption in nationally representative samples of all age-sex categories in Europe in a comparable way. The project was carried out by 14 Member States as well as nine other European countries. Activities of the project included plenary sessions, desk research, and working group activities, building on existing experience from such projects as DAFNE, EPIC, FLAIR Eurofoods-Enfant project, COST Action 99 and others. The proposed method may be used alone, or as a calibration method to accompany existing ongoing studies.

Standardisation of 89Sr using three different methods

Three independent methods were used to standardise a 89Sr solution within the frame of an international comparison organised by BIPM/CCRI(II): 4pi liquid scintillation (LS) spectrometry, based on the CIEMAT/NIST efficiency tracing method, and direct activity measurements with a windowless 4pi CsI(Tl)-sandwich spectrometer and a 4pi pressurised gas proportional counter. Quantitative solid point-like sources were prepared paying special attention during the source drying phase. The impurities in the original solution were measured and corrected for in the results of all three methods. The activity concentration of 89Sr was found to be 26.21 +/- 0.08 kBq g(-1). A new half-life value for 89Sr of 50.61 +/- 0.05 days was determined from the LS measurements. The measurement methods, including the impurity measurements, are described and the results compared. considering the advantages and disadvantages of each method.

Sensitivity of a new grading system for studying nasal polyps with the potential to detect early changes in polyp size after treatment with a topical corticosteroid (budesonide)

We have previously compared different scoring systems for endoscopic staging of nasal polyps. Of the five methods evaluated, we found that two were better than the others with regard to reproducibility and agreement between physicians. One method was lateral imaging, developed by the authors, and the other was a scoring system developed by Lildholdt et al. The main objective of the present study was to compare the sensitivity of these two methods. Another aim was to study the effect on nasal polyposis of topical nasal corticosteroids over a 2-week period. Patients with bilateral nasal polyposis (n = 100) were randomized to a 2-week treatment with a topical corticosteroid (budesonide aqueous nasal spray: 128 microg b.i.d.) or placebo in a double-blind manner. Nasal symptoms were scored before treatment and after 3, 7 and 14 days of treatment, and the patients underwent nasal endoscopy at clinical visits. Patients treated with active substance had an improvement in their symptoms, an effect already detectable after 3 days of treatment, compared with those who received placebo. In addition, a statistically significant decrease in polyp size could be registered after 14 days using lateral imaging but not with the other scoring system. In conclusion, lateral imaging was more sensitive and could detect effects earlier than the other scoring system and can be recommended for the endoscopic staging of nasal polyps in clinical studies.

Self-absorption correction in standardisation of 204Tl

In the frame of the CCRI(II) (Consultative Committee for Ionizing Radiation at the BIPM) working group on 204Tl, dedicated to investigate the problem and explain the reasons for the discrepancy between methods in standardisation of 204Tl, IRMM was assigned the task of studying the influence of self-absorption in solid sources of 204Tl. This was investigated by measuring the activity of quantitative solid sources of different carrier content, prepared by employing a special source drying technique, developed at IRMM. The activity of the solid sources was determined using a 4pi pressurised proportional counter. The self-absorption was calculated using the activity determined from liquid scintillation spectrometry, unaffected by self-absorption, as the reference value. After correction for foil absorption and non-detected X-rays, the self-absorption showed a linear relation to the logarithm of the dry mass of the source. For a typical source, the self-absorption correction for 204Tl was found to be as high as 8%. This article describes a way to minimise and correct for self-absorption in solid sources of 204Tl or nuclides with similar decay properties.

First-pass myocardial perfusion MR imaging with outer-volume suppression and the intravascular contrast agent NC100150 injection: preliminary results in eight patients

The authors evaluated the feasibility of combining single-shot T2-weighted turbo spin-echo magnetic resonance (MR) imaging and first-pass myocardial perfusion MR imaging with an intravascular ultrasmall superparamagnetic iron oxide (USPIO) contrast agent, NC100150 Injection (3 mg of iron per kilogram of body weight). Eight patients with coronary vessel disease underwent T2-weighted turbo spin-echo MR imaging (in-plane resolution, 1-2 mm) during the first pass of the USPIO contrast agent. The mean decrease in signal intensity in myocardium perfused by a nonstenotic coronary artery was 59% +/- 13 (SD) (P < .012) This method is feasible for imaging of myocardial perfusion.