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Biomedical subjects

H Svensson

Publications and source records attributed to H Svensson.

At least 37 records · Page 2Linked to original sources
PubMed2000

The ESTRO-QUALity assurance network (EQUAL).

BACKGROUND AND PURPOSE: ESTRO has set up a Quality Assurance network (EQUAL) to check the dose delivered on axis in reference and non-reference conditions for external radiotherapy. The external audits covered by the network are based on measurements made with mailed thermoluminescent dosimeters (TLD). MATERIAL AND METHODS: The TLD consist of LiF powder type DTL 937 read with a PCL 3 automatic TLD reader. The participating centres are instructed to deliver to the TLDs absorbed doses of 2 Gy calculated with the Treatment Planning System used in clinical routine. A maximum of three photon energies by participating centre have been checked with 10 on-axis points per beam. The quantities checked include the reference beam output, beam output variation with collimator opening, depth dose data and wedge transmission factor. RESULTS: During the 1998 EQUAL programme 102 centres have been checked corresponding to 235 beams (28 (60)Co beams and 207 X-ray beams). About 3% of the outputs in reference conditions show deviations outside tolerance level (>+/-5%). A similar rate of deviation is noted for the percentage depth doses. A rate of deviation (6%) has been observed for the beam output variation (open and wedged beams) and the wedge transmission factor. The analysis of the results shows that for 24 out of the 102 centres, a deviation outside tolerance level is observed at least in one point, mainly for the large and rectangular field sizes and for the wedged beams. CONCLUSIONS: The results for the EQUAL programme show the importance of a quality assurance network in Radiotherapy especially for the non reference points even if they are only located on the beam axis (In order to participate in this network, please contact EQUAL secretariat or download the attached application form ESTRO web site: Dr I.H. Ferreira or Mrs Aline Mechet, EQUAL-ESTRO, Physics Department, Institut Gustave-Roussy 39 Rue Camille Desmoulins, F-94805 Villejuif Cedex, France. e-mail:equal@igr.fr or http://www.estro.be/).

Humans↗
PubMed2000

Brachial plexopathy after postoperative radiotherapy of breast cancer patients--a long-term follow-up.

In 1963-1965 a group of 71 patients operated on for breast cancer with total mastectomy and axillary clearance were given aggressive postoperative telecobalt therapy to the axillary, supraclavicular and parasternal lymph node regions. The prescribed dose to these lymph node regions was 44 Gy in 11 fractions. Only two of the three fields were treated per day. Retrospective dose calculations showed that the total dose in the brachial plexus from the axillary and supraclavicular fields was c. 57 Gy in 16-17 fractions over 3-4 weeks. After a few years, symptoms and signs of brachial plexus injury appeared in many patients, which was reported in some early papers. The cohort has now been followed-up to 34 years. As expected, there was progression of both prevalence and severity of the late effects between 5 and 34 years and 11 of 12 patients who are still alive have paralysis of their arms. The neuropathy seems to be closely linked to fibrosis around the nerve trunks. The use of large daily fractions, in some cases combined with hot spots from overlapping fields, was certainly the cause of the complication.

Adult↗
PubMed2000

Von Langenbeck or Wardill procedures for primary palatal repair in patients with isolated cleft palate--speech results.

Sixty-six patients operated on for isolated cleft palate were evaluated as adults, and their speech was assessed clinically. Forty-four had undergone a von Langenbeck repair at the age of 7 months and 22 a Wardill repair at the age of 18 months. Speech was judged subjectively by the patients themselves, and perceptual assessment was made by three speech pathologists. The remaining speech problems, mainly hypernasality, were moderate or severe in 7 (16%) of the patients in the von Langenbeck group, and in 7 (32%) in the Wardill group. On the other hand, the patients in the Wardill group had fewer fistulas closed, and fewer velopharyngoplasties. There were no significant differences between the two methods regarding speech in adulthood. The Wardill method produced significantly more scar tissue clinically, which carries the potential risk of inhibition of facial growth. The present speech results will therefore be weighed against the outcome of maxillofacial growth for these patients.

Cleft Palate↗
PubMed2000

Effects of transcutaneous nerve stimulation on the microcirculation in chronic leg ulcers.

The purpose of this study was to find out to what extent transcutaneous electrical nerve stimulation (TENS) affects the blood flow in and around chronic lower leg ulcers, as measured with a new technique, laser Doppler imaging (LDI). Fifteen patients, mean age 73 years (range 38-85) with chronic leg ulcers of various causes participated in the study. The duration of the ulcers ranged from 3 months to 16 years. Low-frequency (2 Hz; 10-45 mA) TENS was given for 60 minutes. The changes in blood flow were measured every 5 minutes by LDI. After 60 minutes, mean blood flow had increased in the ulcer by 35%, and in the intact skin surrounding the ulcer by 15%. Even 15 minutes after the TENS had finished there was still a mean blood flow increase of 29% in the ulcer and 9% in the skin. The present results show that TENS has a stimulating effect on local blood circulation in and around chronic ulcers.

Adult↗
PubMed2000

Scalding injuries in immigrant families.

From 1990 to 1996, 214 patients aged up to 6 years were treated at our inpatient burns unit. Ages ranged from 3 to 70 months. Scalding was the cause in 186 cases. The median size of the burned areas was 5.0% (range 0.5%-40%). One hundred and nine were deep dermal burns that required surgical treatment, but this was refused in seven instances. Duration of hospital stay was 11 days (2-45). The number of follow-up visits ranged from 0 to 17. Secondary reconstructions for scarring have been done for seven children so far. Ninety-eight (46%) came from immigrant families, mostly from the Middle East and the Balkans. Of the 186 scalded children, 94 (51%) were immigrants, and they also had a tendency to have more severe injuries. Explanations might be that they were more likely to cook with water and oil, they were unfamiliar with Swedish safety standards and measures, and they had difficulty in communicating (language) and a limited social network. The ensuing scar also may disturb or delay the child's adaptation to the new environment. Our preventive work is now based on a model that states that frequency, type, and severity of injury is dictated by the variables: risk, personality, supervision, and education.

Burns↗
PubMed2000

Dermabrasion of large congenital melanocytic naevi in neonates.

We describe our findings in a series of 12 patients with large congenital melanocytic naevi treated with dermabrasion between the first and fourteenth week of life. Postoperative follow-up ranged from 1-16 years. In all but two cases dermabrasion resulted in an appreciable and stable reduction of the hyperpigmentation, possibly by reducing the number of pigmented cells in the epidermis. In six of our 12 patients, reconstruction using grafts and flaps was done to improve the aesthetic result. Seven years after dermabrasion, one patient developed a minimal deviation melanoma in the treated area, but his subsequent clinical course has been uneventful.

Adolescent↗
PubMed2000

Energy correction factors of LiF powder TLDs irradiated in high-energy electron beams and applied to mailed dosimetry for quality assurance networks.

Absorbed dose determination with thermoluminescent dosimeters (TLDs) generally relies on calibration in 60Co gamma-ray reference beams. The energy correction factor fCo(E) for electron beams takes into account the difference between the response of the TLD in the beam of energy E and in the 60Co gamma-ray beam. In this work, fCo(E) was evaluated for an LiF powder irradiated in electron beams of 6 to 20 MeV (Varian 2300C/D) and 10 to 50 MeV (Racetrack MM50), and its variation with electron energy, TLD size and nature of the surrounding medium was also studied for LiF powder. The results have been applied to the ESTRO-EQUAL mailed dosimetry quality assurance network. Monte Carlo calculations (EGS4, PENELOPE) and experiments have been performed for the LiF powder (rho = 1.4 g cm3) (DTL937, Philitech, France), read on a home made reader and a PCL3 automatic reader (Fimel, France). The TLDs were calibrated using Fricke dosimetry and compared with three ionization chambers (NE2571, NACP02, ROOS). The combined uncertainties in the experimental fCo(E) factors determined in this work are less than about 0.4% (1 SD), which is appreciably smaller than the uncertainties up to 1.4% (1 SD) reported for other calculated values in the literature. Concerning the Varian 2300C/D beams, the measured fCo(E) values decrease from 1.065 to 1.049 +/- 0.004 (1 SD) when the energy at depth in water increases from 2.6 to 14.1 MeV; the agreement with Monte Carlo calculations is better than 0.5%. For the Racetrack MM50 pulsed-scanned beams, the average experimental value of fCo(E) is 1.071 +/- 0.005 (1 SD) for a mean electron energy at depth Ez ranging from 4.3 to 36.3 MeV: fCo(E) is up to 2% higher for the MM50 beams than for the 2300C/D beams in the range of the tested energies. The energy correction factor for LiF powder (3 mm diameter and 15 mm length) varies with beam quality and type (pulsed or pulsed-scanning), cavity size and nature of the surrounding medium. The fCo(E) values obtained for the LiF powder (3 mm diameter and 15 mm length) irradiated in water, have been applied to the EQUAL external audit network, leading to a good agreement between stated and measured doses, with a mean value of 1.002 +/- 0.022 (1 SD), for 170 beam outputs checked (36 electron beam energies) in 13 'reference' radiotherapy centres in Europe. Such fCo(E) data improve the accuracy of the absorbed dose TLD determination in electron beams, justifying their use for quality control in radiotherapy.

Calibration↗
PubMed1999

Similar risk reduction of death of extended-release metoprolol once daily and immediate-release metoprolol twice daily during 5 years after myocardial infarction.

The pooled results from five placebo-controlled postinfarction studies with metoprolol have shown a significant reduction in total mortality. All five studies used immediate-release metoprolol twice daily. An extended-release formulation of metoprolol for once-daily use has since been developed. The aim of the present study was to compare the two different forms of metoprolol with regard to the risk reduction of death for 5 years postinfarction and to analyze whether treatment with the beta-blocker metoprolol is associated with a reduced mortality after the introduction of modern therapies such as thrombolysis, aspirin, and ACE inhibitors. All patients discharged after an acute myocardial infarction (AMI) from Sahlgrenska University Hospital (SU) during 1986-1987 (n = 740, Period I) and during 1990-1991 (n = 1446, Period II) from both SU and Ostra Hospital, Göteborg, Sweden, were included in the study. During Period I, 56% were prescribed immediate-release metoprolol compared with 61% prescribed extended-release metoprolol during Period II. Immediate-release metoprolol was not available for outpatient use during Period II. In a multivariate analysis, all variables significantly associated with either increased or decreased postinfarction mortality during Periods I and II (univariate analysis of patient characteristics, medical history, complications during the AMI medication at discharge) studied were with Cox's proportional hazards model. Treatment with immediate-release metoprolol was significantly associated with reduced mortality over 5 years during Period I (relative risk reduction for total mortality, -34%, P = 0.003; 95% CI for RR, 0.51-0.87), and treatment with extended-release metoprolol was significantly associated with reduced mortality during Period II (-34%, P < 0.0001; 95% CI for RR, 0.53-0.82). Thrombolysis and the use of aspirin and ACE inhibitors were more frequently used during Period II. The results showed that postinfarction treatment with extended-release metoprolol given once daily was associated with a similar risk reduction of death over 5 years as immediate-release metoprolol given twice daily. The data, furthermore, indicate that the beta-blocker metoprolol is associated with a reduced risk of death after the introduction of modern therapy such as thrombolysis, aspirin, and ACE inhibitors.

Adrenergic beta-Antagonists↗
PubMed1999

Syngeneic transplantation in multiple myeloma - a case-matched comparison with autologous and allogeneic transplantation. European Group for Blood and Marrow Transplantation.

Twenty-five patients with multiple myeloma received bone marrow grafts (n = 24) or peripheral blood stem cells (n = 1) from twin donors. The outcome was compared in a case-matched analysis to 125 patients who underwent autologous transplantation, and 125 who underwent allogeneic transplantation. Seventeen patients (68%) receiving twin transplants entered complete remission, which was not significantly different from that of autologous (48%) or allogeneic (58%) transplants. The median overall and progression-free survival for the twins was 73 and 72 months, respectively. The overall survival tended to be better (73 vs 44 months) and the progression-free survival was significantly better (72 vs 25 months) than with autologous transplantation and both were significantly better than with allogeneic transplantation. Three of 17 patients who entered complete remission following transplantation had relapsed at follow-up. This relapse rate was significantly lower than following autologous transplantation and similar to the relapse rate with allogeneic transplantation. Only two twins died of transplant-related toxicity. Six further patients died of progressive or relapsing disease. Syngeneic transplantation in multiple myeloma appears to be the treatment of choice if a twin donor is available. A lower relapse risk than in autotransplantation may be due to reinfusion of malignant cells in some patients treated with this modality or to the presence of a graft-versus-myeloma effect in some syngeneic transplants.

Adult↗
PubMed1999

The nurse's role in drug handling within municipal health and medical care.

In Sweden, elderly care has been transferred from the county councils to the municipalities, resulting in changes in the work tasks of nurses. Today, nurses within municipal health and medical care carry sole responsibility for large groups of care receivers, especially during evenings and weekends. A consequence of this heavy work load is that the nurses have to delegate a number of tasks to subordinate staff. Drug administration is a task which is often delegated. Cases of malpractice involving drug administration, reported from the municipal health and medical service to the regional supervisory units of the National Board of Health and Welfare during a 3-year period, have been analysed in order to gain a deeper understanding of the underlying causes of malpractice. In addition, interviews were conducted with eight nurses, the objective being to find out how they rate their knowledge within this area. The analysis showed that the majority of errors occurred in nursing homes and that the most common errors were administration of the wrong drug, and levels of drugs administered exceeding the prescribed ones. These errors were also common among subordinate staff who had been delegated responsibility for drug administration. Of the nurses interviewed, six out of eight had been close to making errors or had noticed a colleague making an error in conjunction with drug handling. Not all nurses reported errors made to the physician in charge immediately on discovery. It is concluded that through the transformation of elderly care, nurses working within municipal health and medical care have been given a new professional role. This places new demands on their competence, requiring them to make independent judgements and to take their own initiatives.

Aged↗
PubMed1999

Effect of transcutaneous nerve stimulation on microcirculation in intact skin and blister wounds in healthy volunteers.

Healthy non-smoking volunteers participated in two experimental studies in which the circulatory changes induced by transcutaneous nerve stimulation (TENS) were quantified by two different methods. In experimental series 1 (intact skin), nine volunteers were given TENS on the left lower leg for 60 minutes on three occasions at different frequencies each time (2 Hz, 100 Hz, and sham). Changes in blood flow were assessed by laser Doppler imaging technique every five minutes. The mean blood flow increased by 40% during low frequency TENS and by 12% during high frequency TENS. There was no change in mean blood flow during sham stimulation. In experimental series 2 (blister wound), the circulatory changes induced by TENS were studied by intravital video microscopy and computerised image analysis in standard blister wounds on the lower leg. The microcirculatory blood flow, measured as red blood cell velocity (RBC-V) in 5-14 individual capillaries in each wound, was assessed before and during 45 minutes of TENS (2 Hz and 100 Hz). Mean RBC-V increased by 23% during low frequency TENS (n = 6) and by 17% during high frequency TENS (n = 8). The results show that: laser Doppler imaging and intravital video microscopy techniques can be used to study events at the microcirculatory level; the blister wound is an interesting new standard wound for use in clinical studies; and TENS stimulates the peripheral circulation.

Adult↗
PubMed1999

Computing data about patients with cleft lip and palate.

For clinical research and quality control in the treatment of patients with cleft lip and palate (CLP) we created a register based on commercially available computer components. In this report we present the logical organisation of the system and give some representative examples of its applicability. There is great potential for easy access to data, and presentation.

Adult↗
PubMed1999

Extrication of entrapped victims from motor vehicle accidents: the crew concept.

During the extrication process the trauma victim is at high risk for additional injuries or aggravation of existing lesions. Improper handling during extrication with poor concern and knowledge of the ongoing resuscitation process may increase the time spent at the scene and expose the patient to unnecessary risks. Earlier studies report a significant number of neurological injuries that appear to be a result of the extrication process, or of inadequate immobilization during transport. Recent work also underlines the need for appropriate and situation adapted Advanced Life Support (ALS) procedures to improve outcome after prehospital trauma resuscitation. In this paper we present a method for training advanced extrication of trauma victims and the results obtained after five consecutive courses. The training focuses on enhanced liaison between medical and technical team members to optimize synchronization of operations. The course consists of both theoretical lectures and practical training in different crash scenarios. The complexity of the scenarios increases throughout the course and different extrication techniques and strategies are practised. Both the times to extrication and on-scene times were reduced during the 3-day course. Therapeutic interventions and handling of the patient were also improved, in terms of early recognition of medical and technical risks and reduction of the time of no therapy.

Accidents, Traffic↗
PubMed1999

Hormone-sensitive lipase, the rate-limiting enzyme in triglyceride hydrolysis, is expressed and active in beta-cells.

Triglycerides in the beta-cell may be important for stimulus-secretion coupling, through provision of a lipid-derived signal, and for pathogenetic events in NIDDM, where lipids may adversely affect beta-cell function. In adipose tissues, hormone-sensitive lipase (HSL) is rate-limiting in triglyceride hydrolysis. Here, we investigated whether this enzyme is also expressed and active in beta-cells. Northern blot analysis and reverse transcription-polymerase chain reaction demonstrated that HSL is expressed in rat islets and in the clonal beta-cell lines INS-1, RINm5F, and HIT-T15. Western blot analysis identified HSL in mouse and rat islets and the clonal beta-cells. In mouse and rat, immunocytochemistry showed a predominant occurrence of HSL in beta-cells, with a presumed cytoplasmic localization. Lipase activity in homogenates of the rodent islets and clonal beta-cells constituted 2.1 +/- 0.6% of that in adipocytes; this activity was immunoinhibited by use of antibodies to HSL. The established HSL expression and activity in beta-cells offer a mechanism whereby lipids are mobilized from intracellular stores. Because HSL in adipocytes is activated by cAMP-dependent protein kinase (PKA), PKA-regulated triglyceride hydrolysis in beta-cells may participate in the regulation of insulin secretion, possibly by providing a lipid-derived signal, e.g., long-chain acyl-CoA and diacylglycerol.

Adipocytes↗
PubMed1999

Detection of autonomic sympathetic dysfunction in diabetic patients. A study using laser Doppler imaging.

OBJECTIVE: To study signs of the disturbed reflex autonomic sympathetic nerve function in type 1 and type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Measurements were made on 15 type 1 (duration 13-32 years) and on 50 recently diagnosed type 2 diabetic patients (duration 3-4 years). The vasoconstrictor responses in the distal phalanx of the middle finger (locally heated to 40 degrees C) to the cooling of the contralateral arm were measured using Laser Doppler Imaging (LDI). A vasoconstriction index (VAC) was calculated taking age into account and was compared with reference values obtained in 80 control subjects. The diabetic patients were also studied with deep-breathing tests (i.e., the heart-rate variation expressed as the expiration-to-inspiration [E/I] ratio, a test of parasympathetic nerve function). RESULTS: The vasoconstrictor responses to indirect cooling (VAC) were significantly reduced in the fingers of the diabetic patients, both type 2 (0.77 +/- 0.02 V; P < 0.01) and type 1 (0.83 +/- 0.04 V; P < 0.001), compared with the healthy control subjects (0.65 +/- 0.01); the age-corrected VAC (VACz) was slightly more impaired in type 1 than in type 2 diabetic patients. The frequency of an abnormal VACz corresponded well to the frequency of an abnormal E/I ratio in type 1 diabetic patients (approximately 50%), whereas the frequency of an abnormal VACz was significantly higher than an abnormal E/I ratio among type 2 diabetic patients (11/50 vs. 4/50; P < 0.05). CONCLUSIONS: Both type 1 and type 2 diabetic patients have impaired cutaneous blood flow regulation. The VAC index seems to be a promising tool for detection of subclinical changes in autonomic sympathetic function.

Adolescent↗
PubMed1999

Processing of laser-Doppler signals from free flaps.

As conventional graphical laser-Doppler flowmetric (LDF) registrations from free flaps are difficult to interpret we explored the use of refined computerized signal processing to enhance the reliability of the blood flow supervision postoperatively. From eleven free flaps LDF data were collected using a software programme and a personal computer for analysis. Findings were compared with the clinical outcome. Nine flaps healed whereas one had wound problems and one suffered a partial necrosis. From the nine uneventful flaps, a peak within the range of frequencies from 0.04 to 0.23 Hz was seen. In the remaining two, such a low frequency peak could hardly be observed. Frequency analysis using computerized processing of LDF signals thus has the capacity to demonstrate the status of the flap perfusion. The slow wave vasomotion component seems to be of particular importance. Other frequency components warrant further investigation. A custom made monitoring device would be of great clinical value.

Algorithms↗
PubMed1998

Tetanus immunity in patients with hematological malignancies.

The aim of this study was to investigate long-term immunity to tetanus toxoid among patients with hematological disease who had been treated with conventional doses of chemotherapy. Altogether 206 patients with different hematological malignancies were included in the study. There were marked differences between the rates of seronegativity against tetanus, varying from 20% to 70% in different groups of study patients. We found that 21 of 80 (36%) patients with AML, 45 of 80 (56%) with ALL, 12 of 22 (54%) with lymphoma, 4 of 13 (31%) with myeloma and 2 of 11 (18%) with CML were not immune to tetanus. In a multivariate logistic regression model increasing age (P = 0.0001), lymphoid malignancy (P = 0.0005) and advanced disease stage (P = 0.0001) were independent risk factors for loss of tetanus immunity in patients with hematological malignancies.

Adolescent↗