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Biomedical subjects

S Mattsson

Publications and source records attributed to S Mattsson.

At least 19 recordsLinked to original sources
PubMed2003

Long-term study of 99Tc in the marine environment on the Swedish west coast.

The activity concentration of (99)Tc in brown seaweed (Fucus vesiculosus and Fucus serratus) and seawater were analysed in samples collected in 1991, 1995 and 2001 at several stations along the Swedish west coast. In addition to these locations, a well-defined site (Särdal, 56.76 degrees N, 12.63 degrees E) was included with (99)Tc activity concentration data in seaweed from 1967 to 2000. Over the years, the major source of (99)Tc in the coastal waters of western Sweden has been the radioactive liquid discharge from the nuclear fuel reprocessing plant in Sellafield (UK) transported via ocean currents in the North Sea. The (99)Tc activity concentration in seaweed at the Särdal site increased from approximately 30 Bq kg(-1) up to 230 Bq kg(-1) (dry weight) between 1997 and 2000 due to the Sellafield EARP (Enhanced Actinide Removal Plant) discharges in 1995-1996, yielding an approximate transport time of 4-5 years between the Irish Sea and the Kattegat. Due to the very sharp gradient in (99)Tc concentration between the Baltic Sea and the North Sea, (99)Tc is presently one of the best transit tracers for the recent ventilation events in the Baltic Sea.

Cesium Radioisotopes↗
PubMed2003

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.

Adolescent↗
PubMed2002

The influence of different technique factors on image quality of chest radiographs as evaluated by modified CEC image quality criteria.

The Commission of the European Communities (CEC) research project "Predictivity and optimisation in medical radiation protection" addressed fundamental operational limitations in existing radiation protection mechanisms. The first part of the project aimed at investigating (1) whether the CEC image quality criteria could be used for optimization of a radiographic process and (2) whether significant differences in image quality based on these criteria could be detected in a controlled project with well known physical and technical parameters. In the present study, chest radiographs on film were produced using healthy volunteers. Four physical/technical parameters were varied in a carefully controlled manner: tube voltage (102 kVp and 141 kVp), nominal speed class (160 and 320), maximum film density (1.3 and 1.8) and method of scatter reduction (grid (R=12) and air gap). The air kerma at the entrance surface was measured for all patients and the risk-related dose H(Golem), based on calculated organ-equivalent dose conversion coefficients and the measured entrance air kerma values, was calculated. Image quality was evaluated by a group of European expert radiologists using a modified version of the CEC quality criteria. For the two density levels, density level 1.8 was significantly better than 1.3 but at the cost of a higher patient radiation exposure. The correlation between the number of fulfilled quality criteria and H(Golem) was generally poor. An air gap technique resulted in lower doses than scatter reduction with a grid but provided comparable image quality. The criteria can be used to highlight optimum radiographic technique in terms of image quality and patient dose, although not unambiguously. A recommendation for good radiographic technique based on a compromise between image quality and risk-related radiation dose to the patient is to use 141 kVp, an air gap, a screen-film system with speed 320 and an optical density of 1.8.

Adult↗
PubMed2002

No radiation protection reasons for restrictions on 14C urea breath tests in children.

Traditional (14)C urea breath tests are normally not used for younger children because the radiation exposure is unknown. High sensitivity accelerator mass spectrometry and an ultra-low amount (440 Bq) of (14)C urea were therefore used both to diagnose Helicobacter pylori (HP) infection in seven children, aged 3-6 years, and to make radiation dose estimates. The activity used was 125 times lower than the amount normally used for older children and 250 times lower than that used for adults. Results were compared with previously reported biokinetic and dosimetric data for adults and older children aged 7-14 years. (14)C activity concentrations in urine and exhaled air per unit administered activity for younger children (3-6 years) correspond well with those for older children (7-14 years). For a child aged 3-6 years who is HP negative, the urinary bladder wall receives the highest absorbed dose, 0.3 mGy MBq(-1). The effective dose is 0.1 mSv MBq(-1) for the 3-year-old child and 0.07 mSv MBq(-1) for the 6-year-old child. For two children, the 10 min and 20 min post-(14)C administration samples of exhaled air showed a significantly higher amount of (14)C activity than for the rest of the children, that is 6% and 19% of administered activity exhaled per hour compared with 0.3-0.9% (mean 0.5%) of administered activity exhaled per hour indicating that these two children that is were HP positive. For a 3-year-old HP positive child, absorbed dose to the urinary bladder wall was 0.3 mGy MBq(-1) and effective dose per unit of administered activity was 0.4 mSv MBq(-1). Using 55 kBq, which is a normal amount for older children when liquid scintillation counters are used for measurement, the effective dose will be approximately 6 micro Sv to a 3-year-old HP negative child and 20 microSv to a HP positive child. Thus there is no reason for restrictions on performing a normal (14)C urea breath test, even on young children.

Adolescent↗
PubMed2001

Antitumor effect of radioactive cisplatin (191Pt) on nude mice.

PURPOSE: To investigate the effect of (191)Pt-cisplatin in vivo in terms of the antitumor effect and general toxicity on tumor-bearing nude mice. METHODS AND MATERIALS: Tumor-bearing (human squamous cell carcinoma, AB) nude mice were divided into four groups and given, i.p., physiological saline (controls), cisplatin, (191)Pt-cisplatin (80 MBq/mg), or (191)Pt-cisplatin (160 MBq/mg), respectively. Mortality and weight were used as parameters for monitoring general toxic effect, while specific growth delay (SGD) and the area under the logarithm of the relative tumor size curve (AUC-log[RTS]) were used to evaluate the antitumor effect of the treatments. RESULTS: Both SGD and AUC-log(RTS) values showed that (191)Pt-cisplatin was significantly (P < 0.05) more effective in retarding tumor growth than nonradioactive cisplatin. No differences in mortality between the different groups could be observed and no significant differences in weight change between the mice treated with cisplatin or (191)Pt-cisplatin could be seen. CONCLUSION: (191)Pt-cisplatin is a more effective drug than nonradioactive cisplatin in retarding tumor growth on nude mice without adding systemic toxic effects. We believe that radioactive cisplatin may prove to be an alternative to conventional cisplatin; however, the possible toxic effects on organs at risk have to be thoroughly investigated.

Animals↗
PubMed2001

Kidney cadmium as compared to other markers of cadmium exposure in workers at a secondary metal smelter.

BACKGROUND: The aim of the study was to evaluate whether cadmium concentrations in kidney (K-Cd), blood (B-Cd) or urine (U-Cd) could reveal previous occupational cadmium exposure at a metal smelter. METHODS: The study included 90 smelters and 35 controls (B-Cd and U-Cd determination). In a subgroup (N = 33), K-Cd was also determined. RESULTS: B-Cd (median 4.6; range 0.5-53 nmol/L), U-Cd (0. 29; 0.04-1.9 micromol/mol creatinine) and K-Cd (14; 3-61 microg/g wet weight) were similar to reported concentrations in the general Swedish population. In the subgroup, significant associations (P<0. 001) were obtained between B-Cd and K-Cd (r = 0.70), U-Cd and K-Cd (r = 0.60) and between U-Cd and B-Cd (r = 0.62). Multiple regression analyses revealed smoking as the major predictor of K-Cd, B-Cd, and U-Cd. B-Cd and U-Cd were both associated with the duration of employment at the smelter. CONCLUSIONS: There was no statistically significant evidence of previous occupational exposure at the smelter from measurement of K-Cd.

Adult↗
PubMed2001

Long-term external radiation exposure of inhabitants in the western Bryansk region of Russia as a consequence of the Chernobyl accident.

The western Bryansk region in south-western Russia was highly contaminated with 137Cs and 134Cs due to the Chernobyl accident in 1986. In 1990, a joint Nordic-Russian project was initiated in order to make measurements and estimates of the absorbed doses to selected groups of inhabitants in this area. The participating individuals were living in small villages with contamination levels between 0.9 and 2.7 MBq m(-2). Only some villages had been decontaminated. Both school-children and adults participated in the study and the number of persons was between 100 and 130 each year, residing in 5 villages. Every year in September-October, from 1990 to 1998. we performed individual measurements of external absorbed doses, assessed with thermoluminescent (TL) dosemeters (LiF). The mean effective dose per year from external irradiation due to the Chernobyl accident of the inhabitants in the villages ranged between 0.8 and 2.9 mSv during the study period and decreased with an apparent half-time of 3.7-8.2 years, depending on village and group. The highest individual doses within one village were, on average higher by a factor of 3 than the mean value for that village. Under the conservative assumption of a decrease rate in the external effective dose of 2% per year after 1998, individuals in the most highly exposed village are assumed to receive a life-time effective dose of about 75 mSv (between 1986 and 2056) from external exposure to caesium radionuclides. The mean value for the villages under study was estimated to be around 65 mSv using the assumed rate of decrease.

Cesium Radioisotopes↗
PubMed2001

(26)Al investigations at the AMS-laboratory in Lund.

At the accelerator mass spectrometry (AMS) laboratory in Lund, a facility for (26)Al analysis is under development. The sensitivity is expected to be several orders of magnitude higher than with standard mass spectrometry. The planned biomedical program includes studies of aluminium uptake, distribution and retention in man. The initial work has been concentrated on the construction and testing of a new dedicated injector for the accelerator and on the preparation of biological samples for aluminium analysis. The current quality of the facility is presented and the first experimental results reported.

Aluminum↗
PubMed2001

A 10-year study of the 137Cs distribution in soil and a comparison of Cs soil inventory with precipitation-determined deposition.

During a 10-year period, 1988-1998, surface soil samples have been collected at Blentarp in southern Sweden and analysed for 137Cs from the Chernobyl accident and from the nuclear weapons tests. The distance between the sampling plots on the different sampling occasions has been no more than 3 m. The results show that the depth distribution of 137Cs is very similar for each of the sampling occasions, indicating that the caesium migration at this site is very small. The total activity measured in the soil cores is in agreement with the calculated activity of 137Cs deposited at the site after nuclear weapons tests and the Chernobyl accident, based on air activity concentration and the amount of precipitation. The calculated deposition of 137Cs originating from the bomb tests amounts to 1.41 kBq m-2 for the period 1962-1986, which is in agreement with the activity of nuclear weapons fallout measured in the soil samples (1.60 kBq m-2 as a mean value of the first four years of sampling). The calculated activity of 137Cs of Chernobyl origin was 0.79 kBq m-2, which agrees well with the value of 0.79 kBq m-2 measured in the soil samples in 1988.

Cesium Radioisotopes↗
PubMed2001

The use of mercury porosimetry in assessing the effect of different binders on the pore structure and bonding properties of tablets.

This study investigated the effect of binders with different deformability characteristics on the pore structure of tablets composed of binary mixtures. The pore structure was evaluated using mercury porosimetry. The pore size distribution in tablets of both individual components and binary mixtures indicated that the pores in pure binder tablets appeared not to exist to the same degree in composed tablets and were therefore unlikely to substantially contribute to the pore structure. It is therefore suggested that, because the binder undergoes extensive deformation and shearing during compaction, it will exist as relatively small lumps or aggregates or even primary particles that are located between the compound particles. Most of the pores in the binary tablets studied were thus found between particles of the compound and the binder phase. The most deformable binder, polyethylene glycol 3000, had the greatest effect on pore structure, reflected in the greatest increase in tablet strength. An attempt was also made to use mercury porosimetry data to qualitatively assess the effect of a binder on the dominating bond types in a tablet. The results indicated that addition of a binder caused a decrease in the probability of forming solid bridges.

Mercury↗
PubMed2001

Normalisation with coherent scatter signal: improvements in the calibration procedure of the 57Co-based in vivo XRF bone-Pb measurement.

The feasibility of a normalised calibration variable to account for interpatient variability for in vivo 57Co XRF (X-ray fluorescence) finger bone-lead measurements was assessed. Normalising the lead X-ray intensities to the coherent scatter signal was investigated by experiment and Monte Carlo simulation. The X-ray to coherent ratios for a fixed lead concentration were within 5-10% of the mean, within uncertainty, over a physiologically relevant range of finger bone sizes and overlying tissue thicknesses. This is an acceptable level of variation to introduce, as it is less than the uncertainty of a typical in vivo measurement. Normalisation has several advantages compared with the current method of correcting for interpatient variation, as it eliminates the need for transporting extensive equipment to on-site measurements, reduces the subject dose by a factor of two, and increases the objectivity of the bone-Pb assessment.

Bone and Bones↗
PubMed2001

Anogenital electrical stimulation as treatment of urge incontinence in children.

OBJECTIVES: To evaluate retrospectively the result of anogenital afferent stimulation (AGAS) in neurological healthy children with therapy-resistant urge incontinence. PATIENTS AND METHODS: The study included 48 children (24 girls and 24 boys, 5-14 years old) with a diagnosis of bladder instability verified by cystometry in all. Anogenital afferent stimulations were applied using a battery-powered dual constant-current stimulator. The children were stimulated continuously at 10 Hz for 20 min once or twice daily and if required the children and/or the parents continued to apply the treatment at home. For home stimulation a single (anal) channel stimulator was used. The patients were instructed to stimulate for 20 min at maximum intensity two to three times a week until the effects were optimal. The outcome was evaluated retrospectively by comparing voiding/incontinence diaries obtained before and at the follow-up 6-12 months after the end of treatment. RESULTS: AGAS was applied at the clinic for a median (range) of 9 (4-20) times. Thirty-one children continued with home stimulation for another 25 (5-96) sessions. At the follow-up, 18 children were cured and another seven improved, with a leakage score of less than half that before treatment. The treatment was well tolerated by most children. CONCLUSIONS: Anogenital afferent stimulation is an effective, potentially curative treatment in children with severe urge incontinence. Home stimulation is a well accepted adjuvant to treatment at the clinic and improves the outcome.

Adolescent↗
PubMed2001

Evaluation of critical binder properties affecting the compactibility of binary mixtures.

The aim of this study was to identify essential physical and mechanical properties of various binders and to investigate their influence on the tensile strength and porosity of tablets made from binary mixtures with sodium bicarbonate. The binders were characterized according to axial and radial tensile strength after compression into tablets, yield pressure and minimum porosity during compression, and elastic recovery after compression. The addition of a binder generally resulted in an increase in the tensile strength and a decrease in the porosity of the sodium bicarbonate tablets. The location of the binder in the voids between the sodium bicarbonate particles thus decreasing the porosity of the tablet seemed to be an important consideration. Consequently, the addition of binders with a low yield pressure value and a relatively small elastic recovery value (e.g., polyethylene glycol 3000 and polyvinylpyrrolidone) resulted in tablets of low porosity and high tensile strength, especially in the axial direction. The tensile strength of the pure binder also seemed to be important, especially for binders with a lower degree of deformability (e.g., microcrystalline cellulose and pregelatinised starch). The results also indicated the value of using both axial and radial tensile strength measurements in assessing the effect of a dry binder and showed that the importance of different binder properties varied according to the direction of the tablet strength measurements. The results demonstrated that the applied characteristics of the binders used in this study may serve as a useful tool in evaluating the effectiveness of binders.

Porosity↗
PubMed2001

Ecological half-time of radiocesium from Chernobyl debris and from nuclear weapons fallout as measured in a group of subjects from the south of Sweden.

From 1960 to 1980 and between 1987 and 1994 the whole-body content of 17Cs, and when possible also 134Cs, was measured in a group of subjects living in the city of Lund, Sweden (55.7 degrees N, 13.2 degrees E). The results have been analyzed to estimate the effective ecological half-time of fallout radiocesium in humans living in the area. The Lund area (The Province of Skåne) was subjected to a deposition of about 2 kBq m(-2) of pre-Chernobyl 137Cs from nuclear weapons testing and 1 kBq m(-2) of 137Cs from Chernobyl fallout in May 1986. The radiocesium from the nuclear weapons tests in the 1950's and 1960's still gave a significant contribution to the total 137Cs levels in humans in the post-Chernobyl study period (1987-1994) of about 0.4 Bq per kg body weight, which was about 10% of the peak post-Chernobyl concentration level of 137Cs (3.5-4 Bq kg(-1)) in 1987. The effective ecological half-time for 137Cs from Chernobyl was found to be 1.8 +/- 0.2 y. The aggregate transfer factor from deposition to mean activity concentration in man was estimated to be 3.6 Bq kg(-1)/kBq m(-2). These values may be compared with an effective ecological half-time of 1.3 y found in the reference group in the 1960's, and an aggregate transfer factor of 10 Bq kg(-1)/kBq m(-2). This difference is largely explained by the continuous nature of the global fallout leading to contamination on growing crops whereas the Chernobyl fallout occurred just prior to the South Swedish growing season, leading to less efficient transfer to crops and to human diet. The average committed individual effective dose (50 y) from ingested 137Cs from the Chernobyl fallout was estimated to be 0.02 mSv and from the nuclear weapons fallout (1945-1995) to be 0.20 mSv.

Adult↗
PubMed2001

Demonstration of correlations between clinical and physical image quality measures in chest and lumbar spine screen-film radiography.

The ability to predict clinical image quality from physical measures is useful for optimization in diagnostic radiology. In this work, clinical and physical assessments of image quality are compared and correlations between the two are derived. Clinical assessment has been made by a group of expert radiologists who evaluated fulfillment of the European image criteria for chest and lumbar spine radiography using two scoring methods: image criteria score (ICS) and visual grading analysis score (VGAS). Physical image quality measures were calculated using a Monte Carlo simulation model of the complete imaging system. This model includes a voxelized male anatomy and was used to calculate contrast and signal-to-noise ratio of various important anatomical details and measures of dynamic range. Correlations between the physical image quality measures on the one hand and the ICS and VGAS on the other were sought. 16 chest and 4 lumbar spine imaging system configurations were compared in frontal projection. A statistically significant correlation with clinical image quality was found in chest posteroanterior radiography for the contrast of blood vessels in the retrocardiac area and a measure of useful dynamic range. In lumbar spine anteroposterior radiography, a similar significant correlation with clinical image quality was found between the contrast and signal-to-noise ratio of the trabecular structures in the L1-L5 vertebrae. The significant correlation shows that clinical image quality can, at least in some cases, be predicted from appropriate measures of physical image quality.

Computer Simulation↗
PubMed2000

Voiding pattern in healthy newborns.

A 4-hour observation period has been used in infants to investigate suspected bladder dysfunction. The aim of the present study was to extend the usefulness of this protocol by establishing reference values for voiding frequency, intervals, volumes, and residual urine in healthy newborns. The study included 51 healthy newborns, 26 girls and 25 boys, aged 3 to 14 days. During a 4-hour period, all micturitions and residuals were recorded as well as feeding, sleeping, crying, and defecations. The observation was completed with the child undressed to observe the urinary stream during one void. Different provocation tests were tried to induce urinary leakage. All newborns voided with a stream, about once per hour, with a median volume of 23 mL. For each voiding parameter, there was a large inter- and intra-individual variability. Double voidings were common as well as sizable residual volumes. The diuresis was about six times higher than in healthy school children. The healthy newborns did not leak during provocation tests such as manual compression of the bladder. Neurourol. Urodynam. 19:177-184, 2000.

Defecation↗
PubMed2000

Cadmium levels in kidney cortex in Swedish farmers.

The cadmium levels in kidney cortex (K-Cd) did not differ statistically between 10 nonsmoking farmers from the south of Sweden, who had a high intake of locally produced food and who were affected by acid precipitation (as indicated by low pH in the drinking water from their private wells) and 10 farmers less affected (medians: K-Cd, 18 vs. 14 microg/g; water pH, 5.2 vs. 7.8). Neither did 10 farmers selected because of "high" blood cadmium (B-Cd) differ from 10 with "low" [medians: K-Cd, 15 vs. 9 microg/g; B-Cd, 2.6 vs. 1.3 nmol/L (0.29 vs. 0.14 microg/L)]. In all 40 farmers, there was an increase of urinary cadmium levels (U-Cd) with decreasing drinking water pH (r(s) = -0.32, P = 0.045). Further, K-Cd increased with rising B-Cd (r(s) = 0.33, P = 0.037), and both B-Cd (r(s) = 0.73, P = 0.0005), and U-Cd (r(s) = 0.74, P = 0.0005) rose with increasing age. Further, there was an association between U-Cd and B-Cd (r(s) = 0.68, P = 0.0005). We could not demonstrate with certainty any effect of the acid precipitation on the cadmium retention in the farmers, although the association between U-Cd and drinking water pH deserves further study.

Adult↗