Biomedical subjects

H Jönsson

Publications and source records attributed to H Jönsson.

15 recordsLinked to original sources

PubMed2005

Population biokinetic modeling of thyroid uptake and retention of radioiodine.

The aim of this study was to build a population biokinetic model for the uptake and retention of radioiodine in the thyroid of hyperthyroid patients. At Malmö University Hospital (Malmö, Sweden), a database with detailed information from (131)I-iodide therapies has been created. The database consisted of uptake measurement from 422 patients with the diagnoses of diffuse goiter, multinodular goiter, adenoma, and undefined. In total, 2013 uptake measurements, performed from 3 hours to 9 days after intake of a test activity of (131)I, were included. Nonlinear mixed effect modeling (NLME) was used to model the population biokinetics of (131)I. The structural model was parameterized in terms of the level of uptake (A), the rate constant for the absorption to the thyroid (k(a)) and the rate constant for the output from the thyroid (k(e)). Interindividual and interoccasion variabilities were added to all three structural parameters. The following covariates were found to significantly affect the structural model parameters: Diagnosis on A, k(a) and K(e), volume of the thyroid on A and k(a), and age on k(a) and k(e). The interindividual and interoccasion variabilities were in the range of 8%-28%. The variance of the residual error, modeled as an additive, was low. This type of modeling is a powerful tool for biokinetic studies and should be used in other biokinetic areas of radioiodine therapy, such as radiation dosimetry.

Adenoma↗

PubMed2004

Low pH as an inhibiting factor in the transition from mesophilic to thermophilic phase in composting.

During composting of household waste, the acidity of the material affects the process during the initial phase of rising temperature. In this study, the effects of temperature (36-46 degrees C) and pH (4.6-9.2) on the respiration rate during the early phase of composting were investigated in two different composts. A respiration method where small compost samples were incubated at constant temperature was used. The respiration rate was strongly reduced at 46 degrees C and pH below 6, compared to composts with a higher pH or lower temperature. The combination of high temperature and low pH is a possible adverse factor in large-scale composting of food waste.

Analysis of Variance↗

PubMed2003

The potential for disinfection of separated faecal matter by urea and by peracetic acid for hygienic nutrient recycling.

No efficient, reliable, and scale independent disinfection methods for toilet waste are available today for safe recycling of plant nutrients. Therefore, two chemical treatment methods, addition of urea or of PAA (a quaternary mixture of 15% peracetic acid, 15% hydrogen peroxide and 30% acetic acid), were evaluated for disinfection of faecal matter.Degradation of the added urea resulted in 30 g of ammonia nitrogen per kilogram of treated matter and a pH increase to approximately 9.3. This produced an efficient disinfection of E. coli, Enterococcus spp., and Salmonella spp. within 3 weeks (>6log(10) reduction) and a reduction of the chemical resistant Salmonella typhimurium 28b phage, corresponding to a decimal reduction within 7.5 days. No viable Ascaris suum eggs were found after 50 days of treatment. No reduction of spore forming Clostridia spp. was observed. Urea treatment proved to be efficient for disinfection of source separated faecal matter in a scale independent method used for safe recycling of nutrients found in the faecal matter.PAA reduced all of the above indicator organisms within 12 h after application. For this faecal material, with a dry matter content of approximately 10%, an addition of 0.5-1% of PAA (active substance, corresponding to 3.3-6.7% of the Proxitane 15 used) was required before no viable organisms were found in the material. However, this was not tested for the A. suum. No viable spore-forming bacteria or phages were detected. A high rate of bacteria regrowth occurred at 0.15% dosage and 5 days of treatment. PAA is an efficient alternative for disinfection of separated faeces if a rapid treatment is needed.

Animals↗

PubMed2002

The performance and potential of faecal separation and urine diversion to recycle plant nutrients in household wastewater.

In household wastewater and biodegradable solid waste, the main proportion of the plant nutrients are found in the toilet water (i.e. in urine and faeces). In order to recover most of these nutrients, with the purpose of decreasing the emission of eutrophicating agents and of increasing their recycling, present waste and wastewater systems have to be changed. If the urine and the faeces are collected, up to 91%, 83%, and 59% for N, P and K, respectively, can be recovered and recycled from the household wastewater. The urine was collected separately in a double flushed urine-diverting toilet and the faeces were separated from the flushwater using two parallel Aquatrons. The Aquatron separates by a combination of a whirlpool effect, gravitation and surface tension. In this study, nitrogen and phosphorus from the faeces were separated to 73% and 58%, respectively, to the dryer fraction. The combination of faecal separation and urine diversion in the house Ekoporten made it possible to collect 60% of N, 46% of P and 43% of K from the wastewater, indicating that this method is an alternative when aiming to recover plant nutrients while still wanting to use water-flushed, urine-diverting toilets, though the potential to collect the nutrients is much higher.

Agriculture↗

PubMed2002

Improvement of the composting time for household waste during an initial low pH phase by mesophilic temperature control.

Earlier studies indicated that the activity in the initial phase of composting may be reduced when the temperature rises too fast under low pH conditions. A compost reactor experiment on household waste was designed to test whether the degradation time could be reduced by actively preventing the temperature from rising until the pH had reached a certain value. This experiment was performed by monitoring pH in the condensate from the cooled compost gas. The results from 3 + 3 runs with and without temperature control confirmed our hypothesis and a considerable reduction in composting time was achieved. One possible explanation for the results is that the microbes active in the low pH phase are hampered by high temperature. The abrupt rise in pH when the fatty acids are consumed seems to be a good marker of the point when temperature control can be discontinued.

Air Movements↗

PubMed2002

Urine separating sewage systems--environmental effects and resource usage.

Effects of urine separation on the environment and resource usage were estimated using the simulation package ORWARE. Measurements on the urine-separating system in the housing district Palsternackan in Stockholm and on the fertilising effect of the urine were used in the simulations. The tenants were at home 65% of the time and separated 65% of the urine. Under these conditions, urine separation decreased the waterborne emissions of nitrogen and phosphorus by 55% and 33% respectively. Compared to the conventional system, urine separation increased the flow from the wastewater system to agriculture of plant-available nitrogen by a factor of 28, phosphorus by a factor of 1.35 and potassium by a factor of 23. Urine is a well-balanced complete fertiliser with very low concentrations of heavy metals. Urine separation conserved energy as long as the urine was transported distances shorter than 221 km to the field with a truck and trailer. If all the urine had been separated and transported only 1 km, the energy saving would have been 36%. In this and in previous studies, urine separation proved to be an improvement over the conventional system as regards environmental effects and resource usage.

Conservation of Natural Resources↗

PubMed2001

S100B as a predictor of size and outcome of stroke after cardiac surgery.

BACKGROUND: Stroke after cardiac surgery is a clinical problem with often fatal or disabling outcome. To assess severity and probable outcome in affected patients only from clinical and radiological examinations is difficult. The glial-derived protein S100B has been suggested to be a marker of cerebral ischemia, and increased blood concentrations of S100B have been shown to correlate with size of lesion and prognosis after stroke. We studied the validity of S100B as a predictor of size of brain lesion and median term outcome in a consecutive group of patients suffering from stroke after cardiac surgery. METHODS: During a period of 17 months, 20 patients with clinical signs of postoperative stroke were investigated with S100B measurement, sampled at 5, 15 and 48 hours after surgery. All patients were examined with computed tomography or magnetic resonance imaging to confirm the diagnosis, and the size of cerebral infarction was estimated from the radiological examinations. The patients were followed up for survival 24 to 39 months after surgery. RESULTS: S100B concentration in blood 48 hours after surgery correlated with the size of infarcted brain tissue (r = 0.68, p < 0.001). Nine patients had S100B levels exceeding 0.5 microg/L and a 2-year mortality of 78%, whereas the 11 patients with S100B below 0.5 microg/L had a mortality of 18%. CONCLUSIONS: Increased S100B in patients with a stroke following cardiac surgery correlate with the size of infarcted brain tissue. High S100B levels 48 hours after surgery have a negative predictive value for median term survival.

Aged↗

PubMed2001

An information-based neural approach to constraint satisfaction.

A novel artificial neural network approach to constraint satisfaction problems is presented. Based on information-theoretical considerations, it differs from a conventional mean-field approach in the form of the resulting free energy. The method, implemented as an annealing algorithm, is numerically explored on a testbed of K-SAT problems. The performance shows a dramatic improvement over that of a conventional mean-field approach and is comparable to that of a state-of-the-art dedicated heuristic (GSAT+walk). The real strength of the method, however, lies in its generality. With minor modifications, it is applicable to arbitrary types of discrete constraint satisfaction problems.

Algorithms↗

PubMed2001

Normalising impacts in an environmental systems analysis of wastewater systems.

In an environmental systems analysis of four wasterwater systems, the environmental aspects were prioritised by normalisation of predicted impacts from the studied systems to the total impacts from society. Priority Group 1 (highest priority) consisted of discharges (flows) of nitrogen, cadmium, lead and mercury to water, recycling of nitrogen and phosphorus to arable land and flows of heavy metals to arable land. A conventional wastewater system (A) was compared to irrigation of energy forest with biologically treated wastewater (B), liquid composting of toilet wastewater (C) and a conventional system supplemented with urine separation (D). Analysing the aspects in priority group one, systems B-D improved the management of plant nutrients and decreased the flow of heavy metals to water, while the flow to arable land increased, especially for system B. The suggested method is useful in municipal environmental planning and when choosing a wastewater system.

Agriculture↗

PubMed2000

Elimination of S100B and renal function after cardiac surgery.

OBJECTIVES: To determine the biologic half-life of the S100B protein and to investigate if the elimination of S100B depends on glomerular filtration rate (GFR). DESIGN: Prospective human study. SETTING: University hospital. PARTICIPANTS: Sixteen patients who underwent cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Shed mediastinal blood (autotransfusion) was returned to the patients postoperatively and used to study the kinetics of S100B. Iohexol was infused simultaneously to estimate GFR. S100B was measured at 0, 20, 40, 60, and 180 minutes after infusion. Iohexol was measured at 180 and 240 minutes after infusion. MEASUREMENTS AND MAIN RESULTS: S100B followed first-order kinetics, and the biologic half-life for S100B was determined to be 25.3 +/- 5.1 minutes. GFR was determined to be 63.8 +/- 34.4 mL/min. No correlation was found between GFR and S100B half-life. CONCLUSIONS: The elimination of S100B after cardiac surgery is faster than reported earlier and not affected by a moderate decrease in GFR. This finding is important when evaluating S100B levels after cardiac surgery.

Aged↗

PubMed1999

[Good quality of life after heart surgery. Comparable ratings by patients and their relatives].

In a series of 83 patients undergoing coronary artery bypass grafting for angina, perceived QOL (quality of life) was rated by the patients and their spouses, preoperatively and at two and 12 months postoperatively, using the SWED-QUAL instrument. One year after surgery, QOL had improved to a level which might be expected of a normal population comparable in age and gender distribution. Good correlation existed between patient and spouse ratings, especially on physical measures.

Angina Pectoris↗

PubMed1999

S100beta after coronary artery surgery: release pattern, source of contamination, and relation to neuropsychological outcome.

BACKGROUND: S100beta has been suggested as a marker of brain damage after cardiac operation. The aim of this study was to characterize the early S100beta release in detail and relate it to neuropsychological outcome. METHODS: Three groups of patients were investigated. All patients underwent coronary artery bypass surgery (CABG) with extracorporeal circulation. In group A, 110 patients had sampling of S100beta for the first 10 postoperative hours and also underwent neuropsychological testing. In group B, 14 patients were examined for the effect of autotransfusion on S100beta levels. Eight patients in group C had their intraoperative bleeding processed with a cell-saving device. RESULTS: Group A had a heterogeneous release pattern with several rapid elevations in S100beta concentration. In group B, high concentrations of S100beta were found in the autotransfusion blood (range 0.2 to 210 microg/L) with a concurrent elevation of serum S100beta levels after transfusion of shed blood. In group C, high levels of S100beta were found in the blood from the surgical field (12.0+/-6.0 microg/L) and decreased (1.1+/-0.64 microg/L) after wash. Group C had significantly lower S100beta values at the end of cardiopulmonary bypass compared to group A (0.53+/-0.35 microg/L versus 2.40+/-1.5 microg/L). S100beta values were corrected for extracerebral contamination with a kinetic model. With this correction, an association was found between adverse neuropsychological outcome and S100beta release in group A (r = 0.39, p < 0.02). CONCLUSIONS: A significant amount of S100beta is found both in the blood from the surgical field and in the shed mediastinal blood postoperatively. Infusion of this blood will result in infusion of S100beta into the blood and interfere in the interpretation of early systemic S100beta values.

Blood Transfusion, Autologous↗

PubMed1998

Significance of serum S100 release after coronary artery bypass grafting.

BACKGROUND: S100 protein has been suggested to be a serum marker for cerebral complications after cardiac operation and extracorporeal circulation. The aim of this study was to characterize the S100 release pattern after extracorporeal circulation in 515 consecutive patients undergoing coronary artery bypass grafting. METHODS: Clinical variables and outcome were prospectively registered. The cerebral outcome was determined by clinical examination. S100 was measured at the end of extracorporeal circulation, and after 5, 15, and 48 hours. RESULTS: After operation, 13 patients had stroke, 12 had delayed awakening, and 17 had encephalopathy. Early S100 release, immediately after extracorporeal circulation, was associated with age and perfusion time, but not with cerebral outcome. However, S100 release after 5 to 48 hours was associated with cerebral complications and risk factors for such outcome. Patients with stroke had higher S100 levels after 15 to 48 hours. A subset of patients with renal failure had overall higher S100 levels at 5 hours. CONCLUSIONS: Early and late S100 release indicate different mechanisms for release and emphasizes the potential power of this new biochemical marker for cerebral damage.

Adult↗

PubMed1998

Thyroid burdens of 125I in hospital laboratory workers during a 20-y period.

The 125I content in the thyroids of staff members working with 125I at Malmo University Hospital has been measured regularly during a period of 20 y. The measurements were made with a specially designed NaI(Tl) detector, 1.5 mm thick and 124 mm in diameter. Four categories of personnel have been studied: chemists performing routine labeling of mainly proteins and hormones with 125I and using high activities (up to 74 MBq per single labeling); laboratory staff working with in vitro techniques (e.g., radioimmunoassay) using low activities of 125I (approximately 1 kBq in each sample); nuclear medicine staff working with intravenous injections of 125I-labeled radiopharmaceuticals (up to 4 MBq per injection) in patients; administrative staff working in the same department as the above categories, but not handling 125I. Staff from another department, not working with 125I, were used as a control group. During the period 1977-1990, the chemists had a mean 125I activity of 1.5 kBq in their thyroids, giving a yearly absorbed dose of 10 mGy to this organ. An individual value of 7.4 kBq (53 mGy y(-1)) was recorded at one occasion. The mean value of the activity for personnel working with in vitro techniques, mainly radioimmunoassay, was 140 Bq, with an individual value of 4 kBq recorded in this group. The nuclear medicine staff exhibited 30 Bq 125I in their thyroids, on average. Staff members not working with 125I, but working in the same department as someone in the categories above, had up to 25 Bq, indicating diffuse, low-level contamination of 125I in the department. Control subjects from the hospital, not working in any department handling 125I, showed no measurable amount of 125I in their thyroids (<2 Bq). There is a trend towards decreasing internal contamination with time during the period 1977-1990 in spite of the constant use of 125I. This is supposed to be an effect of improved working conditions and active radiation protection information. The further decrease of internal contamination from 1991 to 1996 is due to a decreased use of 125I.

Body Burden↗

PubMed1976

Determination of lead and cadmium in milk with modern analytical methods.

Methods to determine lead and cadmium at the low mug/kg-level in milk were investigated. Methods tested were differential-pulse anodic-stripping voltammetry (DPASV) and flameless atomic-absorption spectrophotometry (FAAS). Under the circumstances in which these methods were used, the analytical procedure based on DPASV was the most sensitive, with an estimated detection limit of about 0.2 mug/1 for lead and cadmium in liquid milk. The pretreatment of the milk samples before the DPASV-analysis included: freeze-drying, ashing in a muffle furnance at 550 degree C and finally dissolution of the ash in 0.1 M-hydrochloric acid. The recoveries of known amounts of lead and cadmium added to milk were 95 and 59%, respectively. A survey of the contents of lead and cadmium in the Swedish manket milk was performed. This investigation showed that the average lead content in Swedish market milk was 2.0 mug/1, with a standard deviation of 0.5 mug/1. The cadmium content was below 0.2 mug/1 in all samples analyzed.

Animals↗