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F Eriksson

Publications and source records attributed to F Eriksson.

13 recordsLinked to original sources
PubMed2000

Radiation pneumonitis after breast cancer irradiation: analysis of the complication probability using the relative seriality model.

BACKGROUND: Toxicity of the respiratory system is quite common after radiotherapy of thoracic tumors; breast cancer patients represent one of the groups for which there is also a long expected survival. The quantification of lung tissue response to irradiation is important in designing treatments associated with a minimum of complications and maximum tumor control. METHODS: The study population consisted of 68 patients who received irradiation for breast cancer at Stage II. Radiation pneumonitis was retrospectively assessed on the basis of clinical symptoms and radiological findings. For each patient, a measure of the exposure (i.e., the lung dose-volume histogram [DVH]) and a measure of the outcome was available. Based on these data, a maximum likelihood fitting to the relative seriality model was performed. The uncertainties of the model parameters were calculated and their impact on the dose-response curve was studied. The optimum parameter set was then applied to 5 other patient groups treated for breast cancer, and the normal tissue complication probability (NTCP) was calculated. Each group was individuated by the radiotherapy treatment technique used; the dose distribution in the lung was described by a mean DVH and the incidence of radiation pneumonitis in each group was known. Lung radiosensitivity was assumed to be homogeneous through all of the calculations. RESULTS: The relative seriality model could describe the dataset. The volume effect was found to be relevant in the description of radiation pneumonitis. Age was found to be associated with increased risk of radiation pneumonitis. Two distinct dose-response curves were obtained by splitting the group according to age. The impact of the parameter uncertainties on the dose-response curve was quite large. The parameter set determined could be used predictively on 3 of the 5 patient groups. CONCLUSION: The complication data could be modeled with the relative seriality model. However, further independent datasets, classified according to the same endpoint, must be analyzed before introducing NTCP modeling in clinical practice.

Age Factors↗
PubMed2000

Long-term cardiac mortality following radiation therapy for Hodgkin's disease: analysis with the relative seriality model.

PURPOSE: (a) To assess the increased risk of death due to ischemic heart disease (IHD) in a group of patients treated for Hodgkin's disease (HD) with radiation therapy (RT) as the primary treatment. (b) To quantify the dose response of IHD using a biophysical model. MATERIALS AND METHODS: Patient material consisted of 157 patients diagnosed for HD between 1972 and 1985 who received RT as the primary treatment at Radiumhemmet, Karolinska Hospital. The general population formed the control group. The RT treatments were reconstructed based on the individual treatment data and simulator films. Individual clinical and dosimetrical data were analyzed with the relative seriality model. The material was also analyzed grouping the material according to dose-volume constraints. RESULTS: Of the 157 patients, 13 (8.3%) died due to IHD. The standardized mortality ratio (SMR) was 5.0 (95% CI, 2.7-8.6). Analysis of dose-volume histograms (DVH) showed an increasing risk with increasing dose to a larger volume fraction. The observed individual clinical complication data could not be modeled unambiguously. The group analysis resulted in the dose-response parameters: D(50)=71 Gy, gamma=0.96 and s=1.0. CONCLUSIONS: A significantly increased risk of death due to IHD following RT for HD was found. The risk was found to increase with higher dose and larger volume fraction irradiated.

Adolescent↗
PubMed2000

The effect of implant design and bone density on maximum torque and holding power for femoral neck fracture devices.

BACKGROUND AND AIMS: Displacement of internally fixed femoral neck fractures due to implant migration is a common problem. This in vitro study was performed to compare maximum torque and holding power for five different implants. MATERIAL AND METHODS: Synthetic porous material with low, medium or high density was used to simulate cancellous bone. The tested implants included three conventional screws (AO, Olmed, Hansson), one screw with threads and a barb (Hybrid), and a pin with a hook (LIH). RESULTS: The Hansson screw provided higher maximum torque in low and medium density blocks when compared with the other implants (p < 0.0001) followed by LIH, Hybrid, Olmed, and AO. For high-density blocks there was no significant difference between Hansson and Hybrid screws, both with significantly higher torque than the other implants. The maximal pullout in low-density blocks differed significantly between all five implants with the Hansson screw providing the highest holding power. For medium and high-density blocks the conventional screws had significantly higher pullout resistance compared with the Hybrid and LIH. CONCLUSION: The in vitro model used seemed to provide reproducible and clinically relevant results. There was a good correlation between material density and holding power for all implants. Screws inserted without predrilling provided higher maximal torque while maximal pull out load seemed less affected by predrilling being used or not.

Bone Density↗
PubMed1998

Role of endogenous pro-enkephalin A-derived peptides in human T cell proliferation and monocyte IL-6 production.

In this paper, we describe that met-enkephalin and/or enkephalin-containing intermediary peptides of the prohormone pro-enkephalin A are produced and secreted by human peripheral blood T cells and monocytes. The peptides are produced after stimulation with the mitogenic monoclonal antibodies anti-CD2.1/2.2 and anti-CD28. In monocytes, enkephalin synthesis was induced by stimulation with lipopolysaccharide. We demonstrate here that these immune cell-derived enkephalins play an important regulatory role in the immune response. By using an anti-sense oligonucleotide strategy we could block the production of enkephalins. Blockade of the production of met-enkephalin and enkephalin-containing intermediary peptides resulted in enhancement of the proliferative T cell response and inhibition of monocyte IL-6 secretion. In vitro reconstitution of the anti-sense treated cultures with synthetic met-enkephalin or the delta-type specific opioid receptor agonist deltorphin could reverse inhibition of monocyte IL-6 production, suggesting that endogenous enkephalins act via membrane opioid receptors. In contrast, addition of met-enkephalin or deltorphin to the anti-sense treated T cell cultures did not have any effect on T cell proliferation.

Antibodies, Monoclonal↗
PubMed1990

Bile acid malabsorption after intestinal bypass surgery for obesity. A comparison between jejunoileal shunt and biliointestinal bypass.

Seventeen patients were operated on with intestinal shunts for morbid obesity, in eight a biliointestinal bypass (BI) was constructed and in the rest a conventional jejunoileal (JI)-shunt. The reduction in weight was similar in both groups, and so was malabsorption of fat, but the BI-group had significantly less bowel motions with less watery diarrhoea. Bile acid malabsorption was measured both chemically by estimating the total amount of faecal bile acids excreted, as well as indirectly by using a 75Se-labelled synthetic bile acid (SeHCAT). Both techniques revealed a substantial loss of bile acid after both types of operation, but patients with BI bypass surgery had significantly lower elimination time of the bile acid than those with JI-shunts. There was a significant negative correlation between SeHCAT retention and total faecal bile acids. However, some patients with low SeHCAT retention had normal or even reduced output of faecal bile acids. Estimation of faecal bile acids may display false negative results when the bile acid pool is decreased. The SeHCAT-test seems to be a better technique for measuring bile acid losses. The study suggests that BI bypass surgery for obesity seems to be advantageous over the JI shunt in reducing the postoperative loss of bile acids and choleretic diarrhoea, without influencing the weight loss.

Adult↗
PubMed1981

Biliointestinal bypass.

To eliminate the blind loop in conventional jejunoileal bypass (JIB) and to maintain enteroheptic circulation of bile, thus hoping to diminish important side-effects of JIB, biliontestinal bypass was introduced in 1975, entailing anastomosis of the blind jejunal loop to a functioning gallbladder. Twenty-two patients with a mean weight of 126 kg (91-154 kg) have had primary bilio-intestinal bypass and another four secondary anastomosis of the gallbladder due to side-effects of the previous JIB. A mean weight reduction of 50 kg was achieved in the 20 patients observed for 24 months, without any serious side-effects, corresponding to a reduction of overweight from 89 per cent preoperative to 14 per cent in a subsample of seven patients followed for five years. Without affecting body weight in the four patients subjected to secondary operation, it ameliorated the side-effects of JIB during observation of more than 6 months. Follow-up with i.v. cholangiography and Tc99 HIDA scintigram conclusively revealed open anastomoses in nine of ten patients adequately judged by the scan and no evidence of gallstones on 15 cholangiograms performed so far. Renal calculi were found in three patients, mainly in the first postoperative year but urine oxalate was in the normal range after more than years of follow-up. It is concluded that jejunoileal bypass combined with cholecystojejunostomy in patients with functioning gallbladders is a safe and relatively simple method for treating morbid obesity in selected cases.

Adult↗