Search PubMed⌕ Search

Biomedical subjects

S Mattsson

Publications and source records attributed to S Mattsson.

At least 73 records · Page 4Linked to original sources
PubMed1997

In vivo measurements of lead in fingerbone in active and retired lead smelters.

OBJECT: The aim of this study was to determine the bone lead concentration in lead smelters and reference subjects, relate them to the lead concentration in blood (B-Pb) and urine (U-Pb), and to use the measured bone lead to calculate a biological half-life for lead in bone. METHOD AND DESIGN: The lead concentration in the second phalanx of the left index finger (bone-Pb) was determined in vivo using an X-ray fluorescence technique. The study population comprised 89 smelters with a history of long-term exposure to lead (71 active and 18 retired) and 35 reference subjects (27 active and 8 retired) with no known occupational exposure to lead. Bone-Pb was related to the previous lead exposure, estimated as a time-integrated B-Pb (CBLI). RESULTS: The retired smelters had the highest bone-Pb (median value 55 micrograms/g wet weight, as against 23 micrograms/g in active smelters) and 3 micrograms/g in the reference subjects. A strong positive correlation was observed between the bone-Pb and the CBLI among both active (rs = 0.73; P < 0.001) and retired (rs = 0.71; P = 0.001) smelters. The corresponding correlations between the bone-Pb and the period of employment were of the same magnitude. For retired workers, there were positive correlations between the bone-Pb and the B-Pb (rs = 0.58; P = 0.011) and U-Pb. (rs = 0.56; P = 0.02). Multiple regression analyses showed that bone-Pb was best described by the CBLI, which explained 29% of the observed variance (multiple r2) in bone-Pb in active workers and about 39% in retired workers. The estimated biological half-life of bone-Pb among active lead workers was 5.2 years (95% confidence interval 3.3-13.0 years). CONCLUSIONS: The high bone-Pb seen in retired workers can be explained by the long exposure periods, the higher exposure levels in earlier decades, and the slow excretion of lead accumulated in bone. The importance of the skeletal lead pool as an endogenous source of lead exposure in retired smelters was indicated by the associations between the B-Pb or U-Pb, on the one hand, and the bone-Pb, on the other. In active workers, the ongoing occupational exposure was dominant. The in vivo X-ray fluorescence technique is still mainly a research tool, and more work has to be done before it can be used more widely in clinical practice. However, over the next decade we can anticipate retrospective, prospective and cross-sectional epidemiological studies in which bone lead determinations reflecting the previous lead exposure in both occupationally and nonoccupationally lead exposed populations are related to various types of adverse health outcomes. Such studies will improve our knowledge of dose-response patterns and provide data that will have an impact on hygienic threshold limit values and prevention of lead-induced diseases.

Adult↗
PubMed1997

In vivo analysis of cadmium in battery workers versus measurements of blood, urine, and workplace air.

OBJECTIVES: To measure in vivo the cadmium concentrations in kidney cortex (kidney-Cd) and in superficial liver tissue (liver-Cd) of nickel cadmium battery workers, and to compare the results with other commonly used estimates of cadmium exposure (current concentrations of cadmium in blood (B-Cd) and urine (U-Cd)) or repeated measurements of cadmium in workplace air (CumAir-Cd). METHODS: The study comprised 30 workers with a range of duration of exposure of 11-51 years. 13 subjects were currently employed, whereas the other 17 had a median period without occupational exposure of eight years before the measurements. The in vivo measurements were made with an x ray fluorescence technique permitting average detection limits of 30 and 3 micrograms cadmium per g tissue in kidney and liver, respectively. RESULTS: 19 of 30 (63%) people had kidney-Cd and 13 of 27 (48%) had liver-Cd above the detection limits. Kidney-Cd ranged from non-detectable to 350 micrograms/g and liver-Cd from non-detectable to 80 micrograms/g. The median kidney-Cd and liver-Cd were 55 micrograms/g and 3 micrograms/g, respectively. Kidney-Cd correlated significantly with B-Cd (r, 0.49) and U-Cd (r, 0.70), whereas liver-Cd correlated significantly with U-Cd (r, 0.58). Neither kidney-Cd nor liver-Cd correlated with the CumAir-Cd. The prevalence of beta 2-microglobulinurea increased with increased liver-Cd. CONCLUSIONS: Current U-Cd can be used to predict the kidney-Cd and liver-Cd measured in vivo. In vivo measurements of kidney-Cd and liver-Cd were not shown to correlate with the individual cadmium exposure estimates, obtained by integration of the cadmium concentration in workplace air. There may be several reasons for this, including uncertainties in the estimate of the individual cumulative exposures as well as in the in vivo measurements. There was a suggestion of a relation between liver-Cd and tubular proteinuria.

Aged↗
PubMed1997

Dosimeter gel and MR imaging for verification of calculated dose distributions in clinical radiation therapy.

A dosimeter gel, based on an agarose gel infused with a ferrous sulphate solution and evaluated in a magnetic resonance scanner, was used for complete verification of calculated dose distributions. Two standard treatment procedures, treatment of cancer in the urinary bladder and treatment of breast cancer after modified radical mastectomy, were examined using pixel-by-pixel and dose volume histogram comparison. The dose distributions calculated with the dose planning system was in very good agreement with the measured ones. However, in the case of the more complicated breast cancer treatment, some discrepancies were found, mainly at the beam abutment region. This may be explained by field displacements errors and by a small limitation of the dose planning utilising small electron beams in this region. The dosimeter gel system have proven to be a useful tool for dosimetry in clinical radiation therapy applications.

Breast Neoplasms↗
PubMed1997

Age-related normal uptake of 99mTc-MDP in the lower spine.

AIM: The uptake of 99mTc-MDP in the lower spine was quantified in connection with ordinary bone scintigraphy. METHODS: Fifty-seven women and seventy-two men (aged 20-69 y), with no signs of metabolic or malignant disease and no history of back pain or atraumatic fractures, were included in the study. RESULTS: The women showed an increase in 99mTc-MDP uptake from the age of 20 y to about 45 y with a decrease from the time of menopause. In contrast to women, the uptake in men showed a slight decrease from the age of 20 y to about 50 y and thereafter a more marked decrease was seen. The major difference between men and women is the high premenopausal uptake in the female skeleton. CONCLUSION: An understanding of age-related changes in 99mTc-MDP uptake, which are indices of the skeletal metabolism, is of importance especially in prevention and treatment of osteoporosis, a common disorder in postmenopausal women.

Adult↗
PubMed1996

Dose distribution at radiographic examination of the spine in pediatric radiology.

STUDY DESIGN: The radiation dose distribution at radiographic examinations of the lumbar spine and the thoracic spine and at examinations for scoliosis has been investigated in pediatric patients. OBJECTIVES: To derive the conversion factors between the entrance surface dose and the mean absorbed dose to the most radiation-sensitive organs, and to determine the dose level and its variation for patients. SUMMARY OF BACKGROUND DATA: Fifty-five patients participated in the survey. Mathematically describable phantoms were used to simulate the body of children of various ages. METHODS: Relative absorbed dose in the body was determined with measurements. The entrance surface dose and the dose-area product were measured for a number of patients. The effective dose and its variation between patients were estimated. RESULTS: The mean entrance surface doses were highest for the lumbar spine examinations (2.6 mGy, anteroposterior projection; 6.7 mGy, lateral projection). The female gonads received the highest dose. The mean entrance surface doses for the thoracic spine examinations were 2.1 mGy for the frontal view and 6.1 mGy for the lateral view. The breasts, thyroid, lungs, and esophagus received the highest absorbed dose. Mean effective dose for one frontal and one lateral view was slightly higher for lumbar spine examinations than for thoracic spine examinations. An optimized scoliosis examination gives a much lower effective dose, about 0.05 mSv (frontal view). If an additional exposure determining the "skeletal age" is performed, the effective dose rises with 0.12 mSv. CONCLUSIONS: Thoracic spine and lumbar spine examinations lead to relatively high-absorbed doses to radiation-sensitive organs. Because the scoliosis investigation is repeated several times, the total effective dose could be considerable.

Adolescent↗
PubMed1996

Application of accelerator mass spectrometry (AMS) for high-sensitivity measurements of 14CO2 in long-term studies of fat metabolism.

Long-term measurements of 14C in CO2 expired after ingestion of 14C-labelled triolein were performed using accelerator mass spectrometry (AMS). About 30% of a given amount of 14C-labelled triolein was catabolized rapidly, while the remaining 70% had a very slow turnover. The study shows the potential of the AMS technique for the study of the long-term biokinetics of 14C-labelled pharmaceuticals. The AMS technique allows the administered activity to be reduced by several orders of magnitude without compromising the study. It may also allow studies of rare drug metabolites.

Adult↗
PubMed1996

Radiopharmaceutical dosage of 99Tcm-HMPAO for cerebral blood flow SPET studies in children.

Four methods of calculating the activity of 99Tcm-hexamethylpropyleneamine oxime to be administered in cerebral blood flow investigations of children were evaluated in patient studies. Three of the methods were based on the size of the child. We also constructed a theoretical dosage model based on physiological data and attenuation effects. The aim of the study was to find a dosage calculation method that gave the same image quality for children of all ages as well as for adults. The results showed that the dosage method based on body weight is the only one of the four methods that does not exhibit an age-dependent variation in image quality and therefore this method is recommended.

Adolescent↗
PubMed1996

Examination technique, image quality, and patient dose in paediatric radiology. A survey including 19 Swedish hospitals.

PURPOSE: Investigation of examination technique, image quality, and absorbed dose to the patients in paediatric radiology. MATERIAL AND METHODS: In total, 19 Swedish hospitals participated in the study. Using a questionnaire, the hospitals described their examination technique for the pelvis, urinary tract, colon, scoliosis, and lung. The image quality and patient dose were experimentally studied for the simulated pelvis examination of a 1-year-old child. This examination was carried out with a test object containing a contrast-detail phantom. TL dosimeters were used to determine the absorbed dose on the surface of the phantom, approximately corresponding to the absorbed dose on the surface of the patient. RESULTS: Examination techniques varied considerably among the hospitals, the most striking difference concerning the film-screen sensitivity. Consequently, there was a variation in the absorbed dose on the surface of the phantom, from 0.09 mGy to 1.7 mGy (mean 0.65 mGy). For a large range of doses, 0.4-1.7 mGy, the image quality was not significantly different. CONCLUSION: The unharmonized, and in many places unoptimized, examination techniques led to a great variation in the absorbed dose to the children examined.

Child↗
PubMed1995

Cadmium in kidneys in Swedes measured in vivo using X-ray fluorescence analysis.

An X-ray fluorescence (XRF) technique using plane polarized X-rays for excitation was used for in vivo measurements of cadmium in the kidney cortex among non-occupationally exposed members of the general population in southern Sweden. The measured concentrations of cadmium in the kidney cortex of smokers (median 28 micrograms/g, n = 10) were significantly higher (P = 0.0036) as compared to those in non-smokers (median 8 micrograms/g, n = 10), and so were the cadmium concentrations in blood and urine. The results show that smoking considerably increases the cadmium concentration in the kidney cortex and that smoking is a major source of cadmium exposure in the general population of Sweden. Except in the presence of very deeply situated kidneys, where the minimum detectable concentration is high, non-invasive in vivo XRF analysis of kidney cadmium should be a useful tool for evaluating the effects of long-term low-level exposure to cadmium and the risk of kidney damage.

Adult↗
PubMed1995

In vivo XRF analysis of mercury: the relation between concentrations in the kidney and the urine.

The objective of this study was to determine the concentrations of mercury in organs of occupationally exposed workers using in vivo x-ray fluorescence analysis. Twenty mercury exposed workers and twelve occupationally unexposed referents participated in the study. Their mercury levels in kidney, liver and thyroid were measured using a technique based on excitation with partly plane polarized photons. The mercury levels in blood and urine were determined using atomic absorption spectrophotometry. The detection limit for mercury in the kidney was exceeded in nine of the exposed workers, but in none of the referents. The mean kidney mercury concentration (including estimates below the detection limits) was 24 micrograms g-1 in the exposed workers, and 1 microgram g-1 in the referents. The association between mercury in the kidney and in urine was statistically significant, but it was unclear whether the relation was linear. The measurements on liver (n = 10) and thyroid (n = 8) in the exposed workers showed mercury levels below the detection limit. The study shows that it is now possible to measure the mercury concentrations in kidneys of occupationally exposed persons, using in vivo x-ray fluorescence. The estimated concentrations are in reasonable agreement with the limited human autopsy data, and the results of animal studies.

Adult↗
PubMed1995

Diuresis and voiding pattern in healthy schoolchildren.

OBJECTIVE: To analyse how differences in diuresis affect the normal pattern of micturition of healthy children. SUBJECTS AND METHODS: Two hundred and six healthy continent schoolchildren, aged 7-15 years, completed a frequency/volume chart for 24 h by recording the time and volume of each micturition. Several diuresis variables were calculated from these charts and compared with sex, age, oral fluid intake, functional bladder capacity, voiding intervals and volumes. RESULTS: The weight-corrected mean diuresis per 24 h varied 10-fold between individuals, independently of recorded fluid intake. In the majority, the diuresis decreased during the night, but the opposite diurnal pattern occurred in 12% of the children. The individual night-time diuresis was positively correlated with functional bladder capacity and the daytime diuresis was positively correlated with voiding frequency. CONCLUSIONS: The weight-corrected diuresis varies many-fold among healthy continent children. A substantial proportion has a reversed diurnal pattern with a larger diuresis during the night. The individual bladder size is adapted to accommodate their typical nightly urine production.

Adolescent↗
PubMed1995

The radiation dose to children from X-ray examinations of the pelvis and the urinary tract.

X-ray examinations of the pelvis and the urinary tract are frequent examinations of children, in which a large part of the trunk is irradiated. The irradiated volume contains many of the most radiation sensitive organs and tissues. The absorbed dose to children during the examination was estimated from measurements with a dose-area product meter and thermoluminescent dosemeters (TLDs). Entrance surface dose and the dose-area product results are presented. Conversion factors between the entrance surface dose and the organ dose were derived. The energy imparted, organ dose and effective dose were determined. The entrance surface dose for one single exposure varied between 0.32 mGy and 8.6 mGy for the urinary tract examination and between 0.26 mGy and 2.89 mGy per exposure for the pelvis examination. These variations are mainly influenced by the body size of the patient. The number of images taken during one examination varied. For the urinary tract investigation, the average number of exposures was six, while the corresponding number for the pelvis examination was two. The average effective dose for a typical urinary tract investigation ranged from 0.9 mSv to 8.5 mSv and from 0.3 mSv to 1.4 mSv for the pelvis examination. The radiation dose depends greatly on the body size. The recommendations to present the results in relation to age have been followed; however, the variation of body size even within each specified age range is significant. It is suggested that doses should be quoted in relation to a more critical parameter than age.

Adolescent↗
PubMed1994

Flow rate nomograms in 7- to 16-year-old healthy children.

To construct flow rate nomograms for children, 180 healthy boys and girls aged 7-16 years were examined with a new kind of flowmeter. Each child presented at least two registrations. The flow rate was significantly higher at the second examination and these micturitions were used to construct the nomograms. The relation between flow rate and volume may be described by the function flow = b volume(c), where b and c describe the slope and curvature, respectively. The advantages of using this relation are that non-parametric statistics can be employed, the variation around the median increases with increasing volume, and it is easy to calculate volume corrected flow rates. The exponent 0.5, often used earlier, was found to overestimate flow rates obtained at low volumes. In the constructed nomograms, the exponent varied between 0.29 and 0.42. The volume corrected maximum flow rate was about 2 ml/s higher in girls than in boys. This difference was significant. The difference of about 1.5 ml/s in average flow rate was not significant. The flow rate increased significantly with age. For volume corrected flow rates, there was, however, no significant change with age. Thus, the increase in flow rate with age is secondary to an increase in voided volume. As a result of these analyses, four nomograms were constructed showing the maximum and average flow rates for boys and girls separately. The flow rates of the new nomograms are on a level with or somewhat higher than the flow rates in previously presented nomograms for both children and young adults.

Adolescent↗
PubMed1994

Urinary flow in healthy schoolchildren.

The urinary free flow in 180 healthy schoolchildren aged 7-16 years was examined with a new kind of uroflowmeter. The examinations were performed at ordinary school toilets and each child presented at least two registrations. Besides the shape of the flow curve, the urinary flow was evaluated by the parameters voided volume, maximum flow rate, average flow rate, flow at 1 second and at 0.5 seconds, time to maximum flow, and voiding time. All parameters were related to sex, age, and body parameters. Two recorded micturitions are considered a minimum to obtain a reliable assessment of the urinary flow curve of a child and the shape of the curve is the most important factor to analyse. The normal flow curve is "bell-shaped" regardless of sex, age, and voided volume, and the urine is emptied in one portion. At the first micturition, more curves are irregular and flow rates are significantly lower than at the second one. Voided volume, maximum flow rate, average flow rate, time to maximum flow, and voiding time increase weakly but significantly with age and body parameters. Maximum flow rate, average flow rate, and the flow at 1 second are significantly higher for girls and are correlated to each other. All examined flow parameters except the flow at 0.5 seconds are significantly correlated to voided volume. The results differ from previous studies of children by larger voided volumes, shorter voiding time and time to maximum flow and by higher values for maximum flow rate, average flow rate, and flow at 1 second.

Adolescent↗
PubMed1994

125I-labelling of an internally 75Se-labelled monoclonal antibody--biodistribution in tumour-bearing nude mice.

A monoclonal antibody, C215, was first internally labelled with 75Se-methionine and then labelled with 125I. The biodistribution of the dual-labelled [125I][75Se]C215 was studied in tumour-bearing nude mice killed 3 days after injection. The biodistribution of the dual-labelled [125I][75Se]C215 was compared with the biodistribution of single-labelled [131I]C215 and [75Se]C215. Iodine-labelled antibodies seem to be damaged during iodination, affecting the disappearance rate and tumour uptake. There were no signs of dehalogenation of circulating antibodies or antibodies taken up in the tumour.

Adenocarcinoma↗
PubMed1994

Urinary incontinence and nocturia in healthy schoolchildren.

A frequency/volume chart was used to investigate the micturition pattern of healthy schoolchildren, aged 7-15 years. Of 242 objectively and subjectively healthy children, incontinence was recorded by 36 (14.9%). Nocturnal enuresis, defined as at least one wet night in three months, occurred in 19 (7.9%) children and daytime incontinence occurred with the same frequency. Four girls had both symptoms. Twenty-seven (11.2%) children woke up to void during the night of the investigation but habitual nocturia was established for only 4.1%. There was no difference in the micturition pattern between continent and incontinent children, and there was no correlation between incontinence, nocturnal micturitions and recorded oral fluid intake. At a follow-up one year later, using a questionnaire administrated to the same children, a persistent high rate of incontinence confirmed the original findings.

Adolescent↗