Improved geometric accuracy of whole body diffusion-weighted imaging at 1.5T and 3T using reverse polarity gradients.

Whole body diffusion-weighted imaging (WB-DWI) is increasingly used in oncological applications, but suffers from misalignments due to susceptibility-induced geometric distortion. As such, DWI and structural images acquired in the same scan session are not geometrically aligned, leading to difficulties in e.g. lesion detection and segmentation. In this work we assess the performance of the reverse polarity gradient (RPG) method for correction of WB-DWI geometric distortion. Multi-station DWI and structural magnetic resonance imaging (MRI) data of healthy controls were acquired at 1.5T (n = 20) and 3T (n = 20). DWI data was distortion corrected using the RPG method based on b = 0 s/mm2 (b0) and b = 50 s/mm2 (b50) DWI acquisitions. Mutual information  (MI) between low b-value DWI and structural data increased with distortion correction (P < 0.05), while improvements in region of interest (ROI) based similarity metrics, comparing the position of incidental findings on DWI and structural data, were location dependent. Small numerical differences between non-corrected and distortion corrected apparent diffusion coefficient (ADC) values were measured. Visually, the distortion correction improved spine alignment at station borders, but introduced registration-based artefacts mainly for the spleen and kidneys. Overall, the RPG distortion correction gave an improved geometric accuracy for WB-DWI data acquired at 1.5T and 3T. The b0- and b50-based distortion corrections had a very similar performance.

Validation of automated whole-body analysis of metabolic and morphological parameters from an integrated FDG-PET/MRI acquisition.

Automated quantification of tissue morphology and tracer uptake in PET/MR images could streamline the analysis compared to traditional manual methods. To validate a single atlas image segmentation approach for automated assessment of tissue volume, fat content (FF) and glucose uptake (GU) from whole-body [18F]FDG-PET/MR images. Twelve subjects underwent whole-body [18F]FDG-PET/MRI during hyperinsulinemic-euglycemic clamp. Automated analysis of tissue volumes, FF and GU were achieved using image registration to a single atlas image with reference segmentations of 18 volume of interests (VOIs). Manual segmentations by an experienced radiologist were used as reference. Quantification accuracy was assessed with Dice scores, group comparisons and correlations. VOI Dice scores ranged from 0.93 to 0.32. Muscles, brain, VAT and liver showed the highest scores. Pancreas, large and small intestines demonstrated lower segmentation accuracy and poor correlations. Estimated tissue volumes differed significantly in 8 cases. Tissue FFs were often slightly but significantly overestimated. Satisfactory agreements were observed in most tissue GUs. Automated tissue identification and characterization using a single atlas segmentation performs well compared to manual segmentation in most tissues and will be valuable in future studies. In certain tissues, alternative quantification methods or improvements to the current approach is needed.

The response of a boreal deep-sea sponge holobiont to acute thermal stress.

Effects of elevated seawater temperatures on deep-water benthos has been poorly studied, despite reports of increased seawater temperature (up to 4 °C over 24 hrs) coinciding with mass mortality events of the sponge Geodia barretti at Tisler Reef, Norway. While the mechanisms driving these mortality events are unclear, manipulative laboratory experiments were conducted to quantify the effects of elevated temperature (up to 5 °C, above ambient levels) on the ecophysiology (respiration rate, nutrient uptake, cellular integrity and sponge microbiome) of G. barretti. No visible signs of stress (tissue necrosis or discolouration) were evident across experimental treatments; however, significant interactive effects of time and treatment on respiration, nutrient production and cellular stress were detected. Respiration rates and nitrogen effluxes doubled in responses to elevated temperatures (11 °C & 12 °C) compared to control temperatures (7 °C). Cellular stress, as measured through lysosomal destabilisation, was 2-5 times higher at elevated temperatures than for control temperatures. However, the microbiome of G. barretti remained stable throughout the experiment, irrespective of temperature treatment. Mortality was not evident and respiration rates returned to pre-experimental levels during recovery. These results suggest other environmental processes, either alone or in combination with elevated temperature, contributed to the mortality of G. barretti at Tisler reef.

Osteochondrosis, Synovial Fossae, and Articular Indentations in the Talus and Distal Tibia of Growing Domestic Pigs and Wild Boars.

Articular osteochondrosis (OC) often develops in typical locations within joints, and the characterization of OC distribution in the pig tarsus is incomplete. Prevalence of OC is high in domestic pigs but is presumed to be low in wild boars. Postmortem and computed tomography (CT) examinations of the talus and distal tibia from 40 domestic pigs and 39 wild boars were evaluated for the locations and frequencies of OC, synovial fossae, and other articular indentations, and frequency distribution maps were made. All domestic pigs but only 5 wild boars (13%) had OC on the talus. In domestic pigs, OC consistently affected the axial aspect of the medial trochlea tali in 11 (28%) joints and the distomedial talus in 26 (65%) joints. In wild boars, all OC lesions consistently affected the distomedial talus. On the articular surface of the distal tibia, all domestic pigs and 34 wild boars (87%) had synovial fossae and 7 domestic pigs (18%) had superficial cartilage fibrillation opposite an OC lesion (kissing lesion). Other articular indentations occurred in the intertrochlear groove of the talus in all domestic pigs and 13 wild boars (33%) and were less common on the trochlea tali. The prevalence of tarsal OC in wild boars is low. In domestic pigs and wild boars, OC is typically localized to the distomedial talus and in domestic pigs also to the medial trochlea tali. Further investigations into the reasons for the low OC prevalence in wild boars may help in developing strategies to reduce OC incidence in domestic pigs.

Impact of early salmon louse, Lepeophtheirus salmonis, infestation and differences in survival and marine growth of sea-ranched Atlantic salmon, Salmo salar L., smolts 1997-2009.

The impact of salmon lice on the survival of migrating Atlantic salmon smolts was studied by comparing the adult returns of sea-ranched smolts treated for sea lice using emamectin benzoate or substance EX with untreated control groups in the River Dale in western Norway. A total of 143 500 smolts were released in 35 release groups in freshwater from 1997 to 2009 and in the fjord system from 2007 to 2009. The adult recaptures declined gradually with release year and reached minimum levels in 2007. This development corresponded with poor marine growth and increased age at maturity of ranched salmon and in three monitored salmon populations and indicated unfavourable conditions in the Norwegian Sea. The recapture rate of treated smolts was significantly higher than the controls in three of the releases performed: the only release in 1997, one of three in 2002 and the only group released in sea water in 2007. The effect of treating the smolts against salmon lice was smaller than the variability in return rates between release groups, and much smaller that variability between release years, but its overall contribution was still significant (P < 0.05) and equivalent to an odds ratio of the probability of being recaptured of 1.17 in favour of the treated smolts. Control fish also tended to be smaller as grilse (P = 0.057), possibly due to a sublethal effect of salmon lice.

Can anti-erosion dentifrices also provide effective plaque control?

OBJECTIVE: While gingivitis and caries continue to be prevalent issues, there is growing concern about dental erosion induced by dietary acids. An oral hygiene product that protects against all these conditions would be beneficial. This study investigated the potential of two anti-erosion dentifrices to inhibit plaque. METHODS: This was a randomized, three-period, two-treatment, double-blind, crossover study evaluating a stannous chloride/sodium fluoride dentifrice (SnCl(2)/NaF, blend-a-med(®) Pro Expert) and a popular anti-erosion dentifrice (NaF, Sensodyne(®) ProNamel(™)). During Period 3, subjects were randomized to repeat one treatment to evaluate any product carryover effects. Each treatment period was 17 days. Test dentifrices were used with a standard manual toothbrush. Digital plaque image analysis (DPIA) was employed at the end of each period to evaluate plaque levels (i) overnight (am prebrush); (ii) post-brushing with the test product (am post-brush); and (iii) mid-afternoon (pm). Analysis was conducted via an objective computer algorithm, which calculated total area of visible plaque. RESULTS: Twenty-seven subjects completed the study. At all time points, subjects had statistically significantly (P ≤ 0.0001) lower plaque levels after using the SnCl(2)/NaF dentifrice than the NaF dentifrice. The antiplaque benefit for the SnCl(2)/NaF dentifrice versus the NaF dentifrice was: am prebrush = 26.0%; am post-brushing = 27.9%; pm = 25.7%. CONCLUSIONS: The SnCl(2)/NaF dentifrice provided significantly greater daytime and overnight plaque inhibition than the NaF toothpaste. When recommending dentifrice to patients susceptible to dental erosion, clinicians can consider one that also inhibits plaque.

Audit of cases with uterine rupture: a process indicator of quality of obstetric care in Angola.

Audit of uterine rupture (UR) used as a process indicator, can identify factors considered avoidable to improve future quality of obstetric care. Records of UR cases at a referral maternity in Luanda were studied retrospectively (n=43) and prospectively (n=67) including basic obstetric information, maternal and foetal outcome, duration of labour, time interval between diagnosis and intervention, drugs used, type of delivery and intervention, surgical procedures and complications. A clinical estimation of avoidability was based on this information. Prevalence of UR was 4.9%. Maternal case fatality rate was 14% and early perinatal mortality 71%. Women with previous Caesarean Section (CS) constituted 28%, grand multiparous women 44% and primiparous women 6%. Uterotonic treatment was given in 36%. Avoidability was estimated to 65%. Regular morbidity-oriented audits with analysis of clinical management reveal weaknesses in obstetric care and may serve as an instrument for future improvement.

Audit of cases with uterine rupture: a process indicator of quality of obstetric care in Angola

Audit of uterine rupture (UR) used as a process indicator, can identify factors considered avoidable to improve future quality of obstetric care. Records of UR cases at a referral maternity in Luanda were studied retrospectively (n=43) and prospectively (n=67) including basic obstetric information, maternal and foetal outcome, duration of labour, time interval between diagnosis and intervention, drugs used, type of delivery and intervention, surgical procedures and complications. A clinical estimation of avoidability was based on this information. Prevalence of UR was 4.9%. Maternal case fatality rate was 14% and early perinatal mortality 71%. Women with previous Caesarean Section (CS) constituted 28%, grand multiparous women 44% and primiparous women 6%. Uterotonic treatment was given in 36%. Avoidability was estimated to 65%. Regular morbidity-oriented audits with analysis of clinical manage-ment reveal weaknesses in obstetric care and may serve as an instrument for future improvement (Afr. J. Reprod. Health 2010; 14[2]:55-62)

Audit of referral of obstetric emergencies in Angola: a tool for assessing quality of care.

By auditing various aspects of referrals of obstetric emergencies, we wanted to study the effectiveness over time of a recently established network of peripheral birth units and two central hospitals in Luanda. 157 women referred for obstetric emergencies were studied regarding clinical outcome and process indicators like waiting time, partogramme quality and Caesarean section rate (CSR). After a change in routines at hospital admission and further partogramme education 92 referred women were compared with the former. Maternal mortality decreased from 17.8% to nil in the second. Total mean waiting time was reduced from 13.7 hours to 1.2 hours. Partogramme quality was significantly improved. CSR increased from 13 to 30%. Prolonged labour was the most common diagnosis.This study demonstrates the importance of clinic-based audit to enhance quality of care regarding referrals of patients with obstetric emergencies.

Audit of referral of obstetric emergencies in Angola: a tool for assessing quality of care

By auditing various aspects of referrals of obstetric emergencies, we wanted to study the effectiveness over time of a recently established network of peripheral birth units and two central hospitals in Luanda. 157 women referred for obstetric emergencies were studied regarding clinical outcome and process indicators like waiting time, partogramme quality and Caesarean section rate (CSR). After a change in routines at hospital admission and further partogramme education 92 referred women were compared with the former. Maternal mortality decreased from 17.8% to nil in the second. Total mean waiting time was reduced from 13.7 hours to 1.2 hours. Partogramme quality was significantly improved. CSR increased from 13 to 30%. Prolonged labour was the most common diagnosis.This study demonstrates the importance of clinic-based audit to enhance quality of care regarding referrals of patients with obstetric emergencies (Afr J Reprod Health 2009; 13[2]:75-85)

Unexpected low prevalence of HIV among fertile women in Luanda, Angola. Does war prevent the spread of HIV?

We studied HIV prevalence and risk factors for HIV infection among fertile women in Luanda for the purposes of obtaining background data for planning of interventions as well as to look into the association of armed conflicts and HIV prevalence in sub-Saharan Africa. The HIV-1 prevalence was 1.7% in an antenatal care group (n = 517) and 1.9% in a family planning group (n = 518). Socioeconomic and sexual background factors did not significantly differ HIV-positive from HIV-negative women. Data on armed conflict factors were matched with HIV prevalence figures among pregnant women in sub-Saharan Africa. The level of armed conflicts was found to be inversely related to HIV prevalence. The low HIV seroprevalence in Luanda is in sharp contrast to the capitals of neighbouring countries. While the spread of HIV may have been hampered by the long armed conflict in the country, it is feared to increase rapidly with the return of soldiers and refugees in a post-war situation. The challenge for preventive actions is urgent. This example may be relevant to other areas with a recent end-of-war situation.

Management of environmental uncertainty in maintenance dredging of polluted harbours in Norway.

High levels of toxic chemicals such as tributyltin (TBT) have been found in the bottom sediments of many Norwegian harbours. Norwegian environmental authorities consider maintenance dredging of such harbours to be potentially harmful to the environment due to the suspension and spread of polluted sediments during the dredging operation. Accordingly, permission to dredge may be denied, or special environmental measures may be required on a case-to-case basis. In this paper, we describe the prevailing uncertainty in the assessment of the environmental effects. Employing Jerome Ravetz' distinction between practical and technical problems in the analysis of a case study from Northern Norway, we show the disadvantages with an exclusive focus on technical solutions. Finally, we discuss informal and simple means to strengthen the presence of the practical problem in the decision process and thereby improve the management of uncertainty.

Further evidence for the decay K+ -->pi+nu(nu).

Additional evidence for the rare kaon decay K+-->pi+nu(nu) has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211pi+nu(nu)) = 1.57(+1.75)(-0.82)x10(-10).

The role of risk assessments in the governance of genetically modified organisms in agriculture.

Controversy abounds in the governance of genetically modified organisms (GMOs) for use in agriculture, partly due to ideological differences. Technological optimism and the "shallow" and the "deep" ecology movements are three influential ideologies that are seen to differ both on value commitments and factual beliefs with respect to GMOs. Factual matters are clarified but not resolved by science, since the scientific community faces uncertainty and apparent contradiction between different research perspectives, notably molecular biology, ecology and the social sciences. Scientific advice plays a key role in the governance of GMOs and ought to be construed so as not to exclude legitimate arguments from ideological perspectives present in the process of governance. This paper analyses the role and use of risk assessments and argues that they be replaced by forms of advice that consider a broader spectrum of scientific evidence and insights, e.g. impact assessments and evaluations of inherent sources of uncertainty and ignorance. A few practical measures to that effect are discussed.

[Does knowledge hurt?]. / Gjør kunnskap vondt?

The rate of production of medical knowledge is high and increasing, and medical practitioners find it hard to keep up. Still, production of new knowledge is normally considered to be unambiguously desirable. This paper is a philosophical reflection upon this assumption of desirability. It is noted that the health sector appears to be subject to the law of diminishing returns; this implies that more doctors and more medical technology may at some level do more harm than good. We argue that Bacon's legitimization of knowledge (knowledge is power) is less forceful in the face of biological and psychosomatic complexity. Medical research may lead to unintended harm through at least two mechanisms. First, biomedical knowledge is reified through the introduction of new medical technology whose effects are not fully known, and may lead to uncontrollable adverse effects on a clinical and societal level. Second, exaggerated attention paid to the production and implementation of biomedical factual knowledge may prevent the development and teaching of personal clinical skills, including phronesis, the individual judgemental powers that enable us to judge which goals are worth striving for, and which are not.

[Risk, uncertainty and ignorance in medicine]. / Risiko, usikkerhet og uvitenhet i medisinen.

Exploration of healthy patients' risk factors for disease has become a major medical activity. The rationale behind primary prevention through exploration and therapeutic risk reduction is not separated from the theoretical assumption that every form of uncertainty can be expressed as risk. Distinguishing "risk" (as quantitative probabilities in a known sample space), "strict uncertainty" (when the sample space is known, but probabilities of events cannot be quantified) and "ignorance" (when the sample space is not fully known), a typical clinical situation (primary risk of coronary disease) is analysed. It is shown how strict uncertainty and sometimes ignorance can be present, in which case the orthodox decision theoretical rationale for treatment breaks down. For use in such cases, a different ideal model of rationality is proposed, focusing on the patient's considered reasons. This model has profound implications for the current understanding of medical professionalism as well as for the design of clinical guidelines.

Intramedullary nailing in humeral shaft fractures. Mechanical behavior in vitro after osteosynthesis with three different intramedullary nails.

The aim of this in vitro study was to compare the mechanical behavior of fixation by the Russell-Taylor nail with the more recent Polarus nail. Fixation with an experimental nail made from polyacetal polymer was also included in the study. Thirty humeri were fractured and randomized to receive one of the three nail types. A four-point nondestructive bending test was performed, as well as torsional testing to failure. The torsional test was designed to record the amount of 'play' (uncontrolled rotation) in the bone/implant construct. The Polarus nail gave higher rigidity of the nail/bone construct than the two other types. The Russell-Taylor nailing exhibited a high degree of 'play' (uncontrolled rotation). The polyacetal nails allowed a large elastic deformation before failure.

Mechanical effects of different localization of the point of entry in femoral nailing.

Twenty pairs of human femora were reamed alternatively on the right or left side, with the opposite side serving as the unreamed control. The fossa piriformis (group I) or tip of the greater trochanter (group II) were chosen for introduction of the intramedullary reamer (Howmedica type). The femora were tested in vertical compression in a MTS mechanical testing machine until failure. In group I, all femora fractured through the entry portal. This happened in only 3 out of 10 in group II, where 7 fractured through the medial part of the femoral neck remote from the portal. The difference is statistically significant. Reduction in strength between the unreamed control side and the reamed femur was median 1486 (23%) in group I and 506 N (11%) in group II. Reduction in energy absorption between the control side and reamed side was median 9786 Nm (44.5%) in group I and 1142 Nm (10.5%) in group II. The difference in energy absorption reduction between groups I and II was statistically significant (P = 0.04). We conclude that reaming through an entry point (portal) in the piriformis fossa weakens the femoral neck and creates a localizing point for fracture.

The impact of hormone replacement therapy on quality of life and willingness to pay.

OBJECTIVE: To measure the gain in quality of life due to hormone replacement therapy for women with mild and severe menopausal symptoms. DESIGN: Prospective study where data on quality of life and willingness to pay were collected by interview. SETTING: Department of Gynaecology at Södertälje Hospital near Stockholm. PARTICIPANTS: One hundred and four women aged 45 to 65 years treated for menopausal symptoms for at least one month. METHODS: Quality of life was measured by the time tradeoff and rating scale methods. The willingness to pay for hormone replacement therapy was investigated using the contingent valuation method. MAIN OUTCOME MEASURES: The quality adjusted life year weight measured with the rating scale and time tradeoff methods, and willingness to pay. RESULTS: The increase in the quality adjusted life year weight due to hormone replacement therapy for women with mild symptoms was 0.26 according to the rating scale method and 0.18 according to the time tradeoff method. For women with severe symptoms the quality adjusted life year weight increased by 0.50 according to the rating scale method and by 0.42 according to the time tradeoff method. The mean willingness to pay for hormone replacement therapy per month was 2300 Swedish krone for women with mild symptoms and 4800 Swedish krone for women with severe symptoms (Pounds 1 = 10.3 Swedish krone). CONCLUSIONS: Hormone replacement therapy leads to a major improvement in quality of life for women with menopausal symptoms. Both for women with mild and severe menopausal symptoms the willingness to pay for the treatment also greatly exceeds the costs, indicating that hormone replacement therapy is economically beneficial for women with menopausal symptoms.