Vascular component of hand-arm vibration syndrome: a 22-year follow-up study.

BACKGROUND: Vibration-induced white finger (VWF) is often assessed using the Stockholm Workshop Scale (SWS) and cold challenge plethysmography. However, long-term longitudinal studies using both methods are scarce. AIMS: To study the long-term course and prognostic factors of VWF assessed with the SWS and photoplethysmography (PPG), and to examine the effects of lifestyle on PPG score, regardless of VWF status. METHODS: Forty male construction workers were examined with a test battery and clinical examination in 1994 and 2016/17. RESULTS: At baseline, the sample comprised 27 workers with, and 13 without, symptoms of hand-arm vibration syndrome (HAVS). Thirty-five workers reported vibration exposure during follow-up. The mean age of the workers was 60 years (45-78) at follow-up. The paired t-test showed that PPG scores deteriorated from 1994 to 2017 in the 27 workers with HAVS in 1994 (mean difference 2.7 min, 95% confidence interval (CI) 0.2-5.2). However, there was no statistically significant change in SWS scores in these workers over time. Smoking and age were associated with PPG score deterioration. Vibration exposure during follow-up predicted SWS score deterioration: 1000 h of exposure predicted a deterioration stage of 0.09 (95% CI 0.03-0.16). Analysis of all 40 workers showed that 2017 PPG scores were associated with positive serum cotinine and self-reported smoking during follow-up. CONCLUSIONS: Whereas age and smoking predicted a PPG deterioration, continued vibration exposure predicted worsening of white finger symptoms. The association of PPG score and smoking should be considered in diagnostic and prognostic factor evaluations.

Venous valve reconstruction in patients with secondary chronic venous insufficiency.

OBJECTIVES: To evaluate the durability of venous valve reconstruction (VVR) and its benefits in terms of symptom improvement, ulcer healing and symptom/ulcer recurrence among patients with secondary chronic venous insufficiency (SCVI) in whom superficial venous surgery and compression treatment had failed. METHODS: During a ten year period (1993-2004) 1800 patients with chronic venous insufficiency (CVI) were evaluated by colour duplex ultrasound (CDU) and ambulatory venous pressure measurement (AVP). Approximately two thirds of patients had SCVI. Initial treatment consisted of compression therapy for a 6 month period. In addition, superficial vein and perforator surgery was performed in those presenting with reflux in these venous systems. 121 patients who did not improve with this treatment were investigated by ascending venography, descending video venography, air plethysmography and measurement of post-ischaemic venous pressure gradient. Thirty two cases having venous reflux without obstruction were selected for VVR. RESULTS: The ulcer healing rate within three months was 68% (13/19 patients). VVR resulted in valvular competence and a clinical success rate of 47% and 40% after 3 and 7 years respectively. In 8/13 (54%) of patients with a healed leg ulcer, a median post-operative AVP reduction of 33 mm Hg (range 20-38) was recorded. The durability of clinical success was numerically longer in patients with haemodynamic improvement (n=10) median 24 months (12-108), when compared with that in those without haemodynamic improvement (n=22) median 18 months (6-108). Popliteal vein reconstruction was part of the VVR procedure in all patients with haemodynamic improvement (post-op. AVP reduction >or=20 mm Hg). VVR at the popliteal level alone or combined with inguinal reconstruction seemed to be the one significant factor associated with haemodynamic improvement (P=0.014, Chi squared). CONCLUSION: VVR may lead to ulcer healing, but when performed at the popliteal level, haemodynamic improvement can be obtained along with a longer recurrence-free period (durability). VVR should be considered in the treatment of patients with SCVI who do not respond to superficial venous surgery and compression treatment.

Assessing doses to interventional radiologists using a personal dosimeter worn over a protective apron.

BACKGROUND: Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure. PURPOSE: To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists. MATERIAL AND METHODS: Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters). RESULTS: Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose. CONCLUSION: A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron.

Noninvasive coronary angiography with 64-channel multidetector computed tomography in patients with acute coronary syndrome.

BACKGROUND: Advances in computer tomography (CT) imaging technology in recent years have facilitated the possibility of noninvasive coronary angiography. PURPOSE: To compare the diagnostic accuracy of 64-channel multidetector computed tomography (MDCT) with conventional invasive coronary angiography (ICA) for the detection of significant coronary stenosis in patients with acute coronary syndrome (ACS). MATERIAL AND METHODS: MDCT was performed in 60 patients classified with non-ST-elevation infarction (NSTEMI) or unstable angina and scheduled for ICA within 3 days. The diagnostic accuracy of MDCT was evaluated using quantitative coronary angiography (QCA) as the gold standard. RESULTS: 48 out of 60 patients had interpretable scans by both MDCT and ICA. On a segment-based analysis, 488 out of 665 segments with a diameter of > or =1.5 mm, as defined by QCA, were interpretable by MDCT. Sensitivity was 78%, specificity 87%, positive predictive value 47%, and negative predictive value 97% in detecting and excluding significant coronary stenosis, as defined with MDCT. On a per patient-based analysis, sensitivity was 89%, specificity 50%, positive predictive value 84%, and negative predictive value 60%. CONCLUSION: Limited diagnostic accuracy restricts the usefulness of coronary MDCT in patient groups with a high pretest probability of disease, such as in acute coronary syndrome.

Treatment with autologous bone marrow mononuclear cells in patients with critical lower limb ischaemia. A pilot study.

BACKGROUND AND AIMS: Treatment with autologous, bone marrow mononuclear stem cells has shown effects in patients with chronic limb ischaemia in one randomized clinical study. The aim of the study was to test the potential effect of stem cell treatment in a strict defined group of patients with stable critical limb ischaemia (CLI). DESIGN: A prospective, combined-centre pilot study. MATERIAL: Eight patients with CLI of the lower extremities, and without any other treatment options. METHODS: Bone marrow cells were harvested from the patient's iliac crest and, after separation, injected into the calf muscles of the affected leg. Outcome was evaluated by digital subtraction angiography (DSA), visual analogue scale (VAS) and several non-invasive circulatory physiological tests. RESULTS: There were no complications from the procedures. Two patients were amputated two months after cell injection. Five patients reported pain relief after four months. Five patients could be evaluated at eight months. According to VAS and physiological tests, they were all either stable or showed improvement. CONCLUSION: This method seems to be a safe option for treating patients with CLI. Inclusion of patients took a long time, mainly because many patients with CLI are offered endovascular treatment in our institution. While symptomatic improvement was found in individual patients, larger trials are required to investigate efficacy. This will probably require multi-centre participation.

Doses to nuclear technicians in a dedicated PET/CT centre utilising 18F fluorodeoxyglucose (FDG).

The first dedicated PET/CT centre in Norway was established at the Norwegian Radiumhospital in Oslo in 2005. Knowing that the introductions of PET-isotopes in nuclear medicine give increased occupational radiation dose to the technicians, a study was carried out in order to map the doses to staff members during different working operations and to see if any dose reducing measures were needed. The results of the study are in good agreement with other studies, and a technician dose of 20-25 nSv per injected MBq of 18F seems to be representative for such centres. For an average injected activity of 350 MBq per patient, the dose limit is reached after handling around 3000 patients annually. For an annual number of less than 500 patients at the centre and rotation of the staff, an annual individual dose for the technicians would realistically be less than 2-3 mSv. Even a major increase in the number of patients will not result in individual doses near the ICRP dose limit.

The influence of variations in the ventilation rate in rooms upon the respiratory dose from inhalation of radon daughters.

Theoretical calculations are reported of the mean respiratory dose from inhalation of short-lived radon daughters under different ventilation condtions. These calculations are related to the variations in ventilation practice over different periods of time.

Radioactivity of building materials and the gamma radiation in dwellings.

Measurements of the radioactivity in some common building materials in Norway are reported, together with calculations of the gamma-ray exposure from walls of different materials. Model rooms are used in calculations of the mean exposure inside concrete, brick and light-weight expanded clay aggregate buildings. These calculations give very good agreement with previous experimental results. The radiological implications of using building materials with high concentrations of radioactivity are also discussed.

Cancer incidence among workers exposed to radon and thoron daughters at a niobium mine.

The aim of this study was to investigate the incidence of cancer among 318 male employees of a niobium mining company which was only operated between 1951 and 1965. Many of the workers, especially underground miners, were exposed to the daughters of radon and thoron and also to thorium. The accumulated doses to the workers from short-lived radon and thoron daughters in the mine atmosphere were assessed to be relatively low; up to 300 working-level months. During the follow-up period 1953-1981, 24 new cases of cancer were observed compared to an expected number of 22.8. Twelve cases of lung cancer had occurred versus 3.0 expected. Among the 77 miners, 9 cases of lung cancer were observed against 0.8 expected. Associations between the occurrence of lung cancer and exposure to alpha radiation and smoking were found. For the radon and thoron daughter exposure, about 50 excess cases per million person-years at risk per working-level month were observed.

Sources of exposure to technologically enhanced natural radiation.

The paper presents a review of sources of enhanced natural radiation and their relative importance. Only sources that have been caused by some human technological activity are discussed, even though higher doses may be received by truly natural sources, such as radium rich ground. The distinction between "natural" and "technologically enhanced" sources and the justification of the different sources are discussed.

Radon exhalation from the ground; method of measurements and preliminary results.

The paper will present a method for measurements of radon exhalation from the ground. The method is based on a combination of activated charcoal and TLD. This method is superior to the traditional charcoal method, because it yields a mean value for the exhalation rate during the whole in-growth time. Furthermore, by using the activated charcoal/TLD method, the decay time is not critical, because the TLD is irradiated from absorbed radon during the decay time. In this way, the method is usable for remote measurements by mail. The method has been tested in areas with "normal" ground and in areas where high indoor radon concentrations previously have been measured. Exhalation measurements were performed near to houses where the indoor radon concentrations were known, and in most cases there was a strong correlation between exhalation rate and indoor radon concentrations. The method thus seems to be usable for classification of building ground.

Chemical and radiological risk factors associated with waste from energy production.

We have tried to estimate the toxic potential of waste from nuclear power plants and from power plants burning fossil fuels. The potential risks have been expressed as 'risk potentials' or 'person equivalents.' These are purely theoretical units and represent only an attempt to quantify the potential impact of different sources and substances on human health. Existing concentration limits for effects on human health are used. The philosophy behind establishing limits for several carcinogenic chemicals is based on a linear dose-effect curve. That is, no lower concentration of no effect exists and one has to accept a certain small risk by accepting the concentration limit. This is in line with the establishment of limits for radiation. Waste products from coal combustion have the highest potential risk among the fossil fuel alternatives. The highest risk is caused by metals, and the fly ash represents the effluent stream giving the largest contribution to the potential risk. The waste from nuclear power production has a lower potential risk than coal if today's limit values re used. If one adjusts the limits for radiation dose and the concentration limit values so that a similar risk is accepted by the limits, nuclear waste seems to have a much higher potential risk than waste from fossil fuel. The possibility that such risk estimates may be used as arguments for safe storage of the different types of waste is discussed. In order to obtain the actual risk from the potential risk, the dispersion of the waste in the environment and its uptake and effects in man have to be taken into account.

Natural radiation--a perspective to radiological risk factors of nuclear energy production.

Radiation doses from natural radiation and from man-made modifications on natural radiation, and different natural radiological environments in the Nodic countries are summarized and used as a perspective for the radiological consequences of nuclear energy production. The significance of different radiation sources can be judged against the total collective effective dose equivalent from natural radiation in the Nordic countries, 92,000 manSv per year. The collective dose from nuclear energy production during normal operation is estimated to 20 manSv per year and from non-nuclear energy production to 80 manSv per year. The increase in collective dose due to the conservation of heating energy in Nordic dwellings is estimated to 23,000 manSv per year, from 1973 to 1984. An indirect radiological danger index is defined in order to be able to compare the significance of estimated future releases of radionuclides from a final repository of spent nuclear fuel to the consequences of natural radionuclides in different environments. The danger index of natural radiological environments will not be significantly increased by future releases of nuclear fuel radionuclides.

Laser Doppler flowmetry in evaluation of skin post-ischaemic reactive hyperaemia. A study in healthy volunteers and atherosclerotic patients.

Laser Doppler flowmetry (LDF) was used to evaluate skin post-ischaemic reactive hyperaemia. Four groups of subjects were examined: healthy young and elderly controls (groups A and B) and patients with intermittent claudication or critical ischaemia (groups C and D). The occlusion tourniquet was placed just proximal to the patella, and measurements were performed on the toe pulp (study 1) and leg skin (study 2). The hyperaemic response on both pulp and leg skin was delayed, diminished and prolonged in claudicators compared with controls. On the toe pulp most patients with critical ischaemia had no hyperaemic response at all, indicating that the local vasodilatory capacity was exhausted at rest. The time from tourniquet deflation to pulp peak hyperaemia was the parameter that most clearly separated between the groups [Group A: 21.5 secs (median), group B: 17 secs, group C: 73 secs and group D: greater than 300 secs]. The time from tourniquet deflation to the first increase in flux is probably dependent on hemodynamic factors in the large extremity vessels, and it is possible that this parameter could be used to define levels of hemodynamic significant stenosis in patients with lower limb atherosclerosis. The results also indicate that laser Doppler flowmetry performed during stress testing may be of value in determining appropriate amputation levels.

The role of blood perfusion and tissue oxygenation in the postischemic transcutaneous pO2 response.

The transcutaneous pO2 (TCpO2) response following release of tourniquet cuff occlusion is expressed as oxygen reappearance time (ORT) and oxygen recovery index (ORI). In the present study the effects of blood perfusion and tissue oxygenation on ORT and ORI in healthy control subjects and two patient groups with peripheral arterial insufficiency were assessed. In control subjects, ORT reflects diffusion time for O2 molecules from capillaries to the TCpO2 sensor. In patients with claudication, ORT was prolonged probably because of delayed postischemic reperfusion and reduced tissue oxygenation. In patients with critical ischemia, prolonged ORT seems to be attributed more to reduced tissue oxygenation than to delayed postischemic reperfusion. ORI in control subjects and patients with claudication apparently depends more on capillary pO2 than on magnitude and duration of the postischemic reperfusion. In patients with critical ischemia, ORI is more related to decreased O2 delivery subsequent to reduced or absent reactive hyperemia response. In addition, increased O2 extraction ("O2 steal") and extensive countercurrent O2 exchange during low flow states may reduce ORT and ORI in severely ischemic skin.

Lymphatic and transcapillary forces in patients with edema following operation for lower limb atherosclerosis.

Intralymphatic end pressure and Starling pressures (interstitial fluid pressure (Pif), plasma and interstitial fluid colloid osmotic pressures (COPpl and COPif)) were measured in leg subcutaneous tissue in 5 patients with local leg edema following femoropopliteal reconstruction for lower limb atherosclerosis. Superficial lymphatics were cannulated proximal to the ankle and the catheter was connected to either syringes for determination of lymph flow and colloid osmotic pressure (COPl), or to a pressure transducer for measurement of intralymphatic end pressure. Samples of interstitial fluid were collected by implantation of nylon wicks and Pif was measured by the "wick-in-needle" technique. In all patients normal end pressure waves with maximum values ranging between 30 and 40 mmHg were recorded, indicating that the ischemia prior to surgery had not significantly affected the intrinsic mechanism for lymph propulsion. COPif of the operated leg averaged 5.7 mmHg +/- 1.0 which was 0.9 mmHg +/- 0.7 higher than the corresponding COPl. This supports the theory of "preferential channels" between the capillaries and the lymphatics. There was a statistically significant correlation between lymph flow and estimated capillary pressure (reabsorption pressure), capillary filtration coefficient, calf blood flow and Pif. According to this study the capillary pressure should at least be 11 mmHg before production of lymph occurs.

Alterations in capillary permeability in the lower limb of patients with chronic critical limb ischaemia and oedema.

BACKGROUND: Oedema formation in lower limbs of patients with chronic critical limb ischaemia (CLI) is a common clinical feature. The rate of fluid filtration through the capillary wall depends on the capillary permeability, i.e. capillary filtration coefficient (CFC). In order to elucidate the pathogenesis of this ischaemic oedema, CFC was measured in the limbs with CLI and oedema and was compared with CFC measurements both in the contralateral sides and in the lower limbs of a control group. PATIENTS AND METHODS: Eleven women and 4 men, with a mean age of 75 +/- 8.8 years, with unilateral CLI and leg and foot oedema were included. Leg and foot volume was measured with water displacement volumetry (WDV). CFC was measured in both limbs by strain-gauge plethysmography using a double-stranded mercury in silicone strain gauge around the middle portion of the foot. As a control group, 8 patients, 5 women and 3 men, with a mean age of 77 +/- 7.6 years with a proximal femur fracture were included and the CFC in this group was measured in the foot of the non-fractured limb. RESULTS: Mean CFC in the limbs with CLI and oedema was 0.0036 +/- 0.001 ml/min.100 ml.mmHg, significantly greater than both the contralateral limbs (0.0019 +/- 0.0003 ml/min.100 ml.mmHg, p < 0.01) and mean CFC in the control limbs (0.0017 +/- 0.0002 ml/min.100 ml.mmHg, p < 0.003). There was a mean volume difference of 13 +/- 9% between limbs with CLI and contralateral sides measured by WDV. There was no significant correlation between total leg-foot volume and CFC (p > 0.05). CONCLUSION: CFC in the ischaemic limb was twice as great as both the contralateral side and the limbs of the control group. It is therefore concluded that an increased CFC is probably one of the important factors in the development of this ischaemic oedema.

The distribution of oedema in the lower limb of patients with chronic critical limb ischaemia: a study with computed tomography.

BACKGROUND: A substantial number of patients with chronic critical limb ischaemia (CLI) have considerable oedema at the distal leg and foot of non deep venous thrombosis origin. The primary aim of the present study was to quantify the distribution of oedema in the different tissues of the leg and foot by applying computed tomography and planimetry. The interstitial fluid hydrostatic pressure (Pif) in the subcutaneous tissue was measured to evaluate the effect of oedema on local tissue pressure. PATIENTS AND METHODS: Six men and 12 women with unilateral CLI and peripheral pitting oedema were included. Cross sectional areas (CSA) of subcutaneous tissue, muscle and bone were measured by computer tomography combined with planimetry to assess the distribution of oedema within the soft tissues. Pif was measured by "wick-in-needle" technique. RESULTS: The median total CSA of soft tissue, subcutaneous and muscle tissues at the foot level were respectively 17%, 34% and 9% greater in the limbs with CLI compared to the contralateral limb (p < 0.001). At ankle level these differences were 13%, 30% and 4%, respectively (p < 0.001). At the level of the calf these differences were not significant. Mean Pif in the limbs with CLI was 0.3 mmHg, significantly higher than in limbs without CLI (-1.8 mmHg), (p < 0.003). CONCLUSION: The study verified oedema of considerable magnitude at the ankle and foot. The great part of the oedema was located within the subcutaneous tissue, which was associated with a relatively moderate, but significant increase in Pif confirming the high compliance of the subcutaneous tissue. The combination of the excessive fluid and increased Pif in the interstitial tissue might aggravate the microcirculation. The aetiology of oedema formation is probably multifactorial.

The concentration of protein-compounds in interstitial tissue of patients with chronic critical limb ischaemia and oedema.

BACKGROUND: Many of chronic critical limb ischaemia (CLI) patients have distal leg and foot oedema. Previous electronmicroscopic studies have shown that chronic severe ischaemia may cause hypoxic damage of the capillary endothelium, including morphological changes i.e. multiplicated/thickened basal lamina, and formation of interendothelial gaps. To assess the functional consequences of these morphologic derangements, where proteins can leak through, we investigated the composition of the interstitial fluid in oedematous ischaemic limbs. PATIENTS AND METHODS: Nine female and 3 male patients with a mean age of 79 +/- 7.9 years were included. All had unilateral CLI and peripheral pitting oedema. Leg and foot volume was measured with water displacement volumetry. Blister suction technique was used to collect subcutaneous interstitial fluid. The concentration of albumin, transferrin, immunoglobulin G and alpha 2-macroglobulin in plasma and blister fluid was measured by immunoturbidimetry. Nine patients, 8 women and 1 man with a mean age of 83 +/- 5.5 years with a proximal femur fracture served as an age-matched control group. RESULTS: The mean concentration of albumin in blister fluid was significantly lower in the patients, whereas the mean concentration of alpha 2-macroglobulin in blister fluid did not differ between patients and controls. Mean ratio between concentrations in blister and serum of albumin, transferrin and immunoglobulin G in the limbs with CLI and oedema were significantly lower than respective values in the control group. However, there was no significant difference in the ratio of alpha 2-macroglobulin between these groups. CONCLUSION: A higher transcapillary concentration gradient for proteins in CLI limbs signifies an increase in the net osmotic pressure gradient across the capillary wall, which may be a potential oedema limiting factor.

Assessment of the radiological impact of using fly ash in cement.

The radiological consequences of using fly ash as a component of cement are discussed. Measurements of the activity concentrations of the fly ash and cement are reported together with measurements of emanation coefficients and exhalation rates. The radon-exhalation rate was found to be significantly lower in concrete containing fly ash than in ordinary concrete. Dose calculations suggest that fly ash will contribute to a reduction in effective dose equivalent due to the reduced radon-exhalation rate.