Aerobic exercise prior to task-specific training to improve poststroke motor function: A case series.

BACKGROUND: Aerobic exercise can improve upper limb motor function in both healthy and stroke populations. Research in animals after stroke has shown that aerobic exercise combined with forelimb motor training improved forelimb motor function more than aerobic exercise or motor training alone. There is a lack of knowledge about this combined intervention in humans after stroke. PURPOSE: These 2 case reports describe the exploratory implementation of a combined aerobic exercise and task-specific training intervention to improve upper limb motor function in one person in subacute stroke recovery and one person in chronic stroke recovery. METHODS: Case descriptions Subacute participant: 45-year-old female, 3 months after ischemic stroke resulting in left-sided hemiparesis affecting her non-dominant upper limb, with a baseline Action Research Arm Test (ARAT) score of 10/57 and Wolf Motor Function Test (WMFT) score of 39/75. Chronic participant: 69-year-old female, 14 years after ischemic stroke resulting in right-sided hemiparesis affecting her non-dominant upper limb, with a baseline ARAT score of 13/57 and WMFT score of 34/75. Intervention Participants performed 30 min of lower limb cycling immediately prior to 30 min of upper limb task-specific training. Sessions were undertaken 3 times a week for 8 weeks in a university rehabilitation laboratory. Results The combined intervention was feasible and perceived as acceptable and beneficial. Participants improved their upper limb motor function on the ARAT (subacute participant = 4 points; chronic participant = 2 points) and WMFT (subacute participant = 5 points; chronic participant = 3 points). Participants improved their aerobic fitness (subacute participant = +4.66 ml O2 /kg/min; chronic participant = +7.34 ml O2 /kg/min) and 6-minute walking distance (subacute participant = +50 m; chronic participant = +37 m). Discussion Combining aerobic exercise with task-specific training may be a worthwhile therapeutic approach to improve upper limb motor function suitable for persons in the subacute or chronic phase after stroke.

Home-based Reach-to-Grasp training for people after stroke is feasible: a pilot randomised controlled trial.

OBJECTIVE: To determine feasibility of a randomised controlled trial (RCT) of home-based Reach-to-Grasp training after stroke. DESIGN: single-blind parallel group RCT. PARTICIPANTS: Residual arm deficit less than 12 months post-stroke. INTERVENTIONS: Reach-to-Grasp training in 14 one-hour therapist's visits over 6 weeks, plus one hour self-practice per day (total 56 hours). CONTROL: Usual care. MAIN MEASURES: Action Research Arm Test (ARAT), Wolf Motor Function Test (WMFT), pre-randomisation, 7, 12, 24 weeks post-randomisation. RESULTS: Forty-seven participants (Reach-to-Grasp=24, usual care=23) were randomised over 17 months. Reach-to-Grasp participants received a median (IQR) 14 (13,14) visits, and performed 157 (96,211) repetitions per visit; plus 30 minutes (22,45) self-practice per day. Usual care participants received 10.5 (5,14) therapist visits, comprising 38.6 (30,45) minutes of arm therapy with 16 (6,24) repetitions of functional tasks per visit. Median ARAT scores in the reach-to-grasp group were 8.5 (3.0,24.0) at baseline and 14.5 (3.5,26.0) at 24 weeks compared to median of 4 at both time points (IQR: baseline (3.0,14.0), 24 weeks (3.0,30.0)) in the usual-care group. Median WMFT tasks completed at baseline and 24 weeks were 6 (3.0,11.5) and 8.5 (4.5,13.5) respectively in the reach-to-grasp group and 4 (3.0,10.0), 6 (3.0,14.0) in the usual care group. Incidence of arm pain was similar between groups. The study was stopped before 11 patients reached the 24 weeks assessment. CONCLUSIONS: An RCT of home-based Reach-to-Grasp training after stroke is feasible and safe. With ARAT being our preferred measure it is estimated that 240 participants will be needed for a future two armed trial.

Effect of orthostatic hypotension on sustained attention in patients with autonomic failure.

INTRODUCTION: Orthostatic hypotension has been associated with impaired cognitive function, but cognitive function during orthostatic hypotension has hardly been studied. We studied the effect of orthostatic hypotension, induced by head-up tilt (HUT), on sustained attention in patients with autonomic failure. METHODS: We studied the sustained attention to response task (SART) in the supine position and during HUT in 10 patients with autonomic failure and 10 age-matched and sex-matched controls. To avoid syncope, the tilting angle was tailored to patients to reach a stable systolic blood pressure below 100 mm Hg. Controls were all tilted at an angle of 60°. Cerebral blood flow velocity, blood pressure and heart rate were measured continuously. RESULTS: In patients, systolic blood pressure was 61.4 mm Hg lower during HUT than in the supine position (p<0.001). Patients did not make more SART errors during HUT than in the supine position (-1.3 errors, p=0.3). Controls made 2.3 fewer errors during SART in the HUT position compared to the supine position (p=0.020). SART performance led to an increase in systolic blood pressure (+11.8 mm Hg, p=0.018) and diastolic blood pressure (+5.8 mm Hg, p=0.017) during SART in the HUT position, as well as to a trend towards increased cerebral blood flow velocity (+3.8 m/s, p=0.101). DISCUSSION: Orthostatic hypotension in patients with autonomic failure was not associated with impaired sustained attention. This might partly be explained by the observation that SART performance led to a blood pressure increase. Moreover, the upright position was associated with better performance in controls and, to a lesser extent, also in patients.

Protocol variations and six-minute walk test performance in stroke survivors: a systematic review with meta-analysis.

Objective. To investigate the use of the six-minute walk test (6MWT) for stroke survivors, including adherence to 6MWT protocol guidelines and distances achieved. Methods. A systematic search was conducted from inception to March 2014. Included studies reported a baseline (intervention studies) or first instance (observational studies) measure for the 6MWT performed by stroke survivors regardless of time after stroke. Results. Of 127 studies (participants n = 6,012) that met the inclusion criteria, 64 were also suitable for meta-analysis. Only 25 studies made reference to the American Thoracic Society (ATS) standards for the 6MWT, and 28 reported using the protocol standard 30 m walkway. Thirty-nine studies modified the protocol walkway, while 60 studies did not specify the walkway used. On average, stroke survivors walked 284 ± 107 m during the 6MWT, which is substantially less than healthy age-matched individuals. The meta-analysis identified that changes to the ATS protocol walkway are associated with reductions in walking distances achieved. Conclusion. The 6MWT is now widely used in stroke studies. The distances achieved by stroke patients indicate substantially compromised walking ability. Variations to the standard 30 m walkway for the 6MWT are common and caution should be used when comparing the values achieved from studies using different walkway lengths.

Attentional focus of feedback for improving performance of reach-to-grasp after stroke: a randomised crossover study.

OBJECTIVE: To investigate whether feedback inducing an external focus (EF) of attention (about movement effects) was more effective for retraining reach-to-grasp after stroke compared with feedback inducing an internal focus (IF) of attention (about body movement). It was predicted that inducing an EF of attention would be more beneficial to motor performance. DESIGN: Crossover trial where participants were assigned at random to two feedback order groups: IF followed by EF or EF followed by IF. SETTING: Research laboratory. PARTICIPANTS: Forty-two people with upper limb impairment after stroke. INTERVENTION: Participants performed three reaching tasks: (A) reaching to grasp a jar; (B) placing a jar forwards on to a table; and (C) placing a jar on to a shelf. Ninety-six reaches were performed in total over one training session. MAIN OUTCOME MEASURES: Kinematic measures were collected using motion analysis. Primary outcome measures were movement duration, peak velocity of the wrist, size of peak aperture and peak elbow extension. RESULTS: Feedback inducing an EF of attention produced shorter movement durations {first feedback order group: IF mean 2.53 seconds [standard deviation (SD) 1.85]; EF mean 2.12 seconds (SD 1.63), mean difference 0.41 seconds; 95% confidence interval -0.68 to 1.5; P=0.008}, an increased percentage time to peak deceleration (P=0.01) when performing Task B, and an increased percentage time to peak velocity (P=0.039) when performing Task A compared with feedback inducing an IF of attention. However, an order effect was present whereby performance was improved if an EF of attention was preceded by an IF of attention. CONCLUSIONS: Feedback inducing an EF of attention may be of some benefit for improving motor performance of reaching in people with stroke in the short term; however, these results should be interpreted with caution. Further research using a randomised design is recommended to enable effects on motor learning to be assessed.

Parental history of Alzheimer disease associated with lower plasma apolipoprotein E levels.

BACKGROUND: Variation in APOE genotype is a determinant of Alzheimer disease (AD), but the risk associated with variation in plasma apoE levels has yet to be determined. Here, we studied offspring with and without a parental history of AD to identify the effect of plasma apoE levels at middle age on the risk of late-onset AD. METHODS: Some 203 offspring from 92 families with a parental history of AD were compared with 197 offspring from 97 families without a parental history of AD. APOE genotypes and plasma apoE levels were assessed in all offspring. Difference in plasma apoE level between subjects with and without a parental history of AD was calculated using robust linear regression, both stratified and adjusted for APOE genotype. RESULTS: Offspring with a parental history of AD were more likely to be an APOE epsilon4 allele carrier (46% vs 21%, p < 0.001) than offspring without such a parental history. Mean plasma apoE levels strongly decreased from epsilon2 to epsilon3epsilon3 to epsilon4 carriers (p < 0.001). Offspring with a parental history of AD had lower plasma apoE levels than subjects without such a history, both in analyses adjusted for APOE genotype (difference: -0.21 mg/dL, p = 0.02) and when using standardized Z scores, when stratified for APOE genotype (difference: -0.22, p = 0.009). CONCLUSIONS: Our findings suggest that lower plasma apoE levels in middle age could be a risk factor for Alzheimer disease in old age, independent of APOE genotype.

APOE genotype modulates the effect of serum calcium levels on cognitive function in old age.

OBJECTIVE: The APOE genotype and serum calcium levels have both been associated with cognitive impairment. Animal studies have shown variation in apoE isoforms to play a critical role in intraneuronal calcium homeostasis, but the contribution of this interaction to cognitive function in man is unknown. Here, we studied whether the APOE genotype modulates the association between serum calcium levels and cognition. METHODS: Within the Leiden 85-plus Study, a prospective population-based study of 599 subjects aged 85 years, we measured serum calcium levels and APOE genotype at baseline. During a 5-year follow-up period, cognitive function was annually assessed using the Mini-Mental State Examination (MMSE) and a standardized neuropsychological test battery. RESULTS: Both at baseline and during follow-up, high serum calcium levels were associated with worse cognitive function in epsilon3epsilon4 carriers and to a lesser extent in epsilon3epsilon3 carriers, but not in epsilon2epsilon3 carriers. The MMSE score during the entire follow-up period differed between those with high and low serum calcium levels, with 5.5 points in epsilon3epsilon4 carriers (p < 0.001), 1.6 points in epsilon3epsilon3 carriers (p = 0.010), and 0.1 point in epsilon2epsilon3 carriers (p = 0.935). Formal testing showed an interaction between APOE genotype and serum calcium levels in relation to global cognitive function (p = 0.003). CONCLUSIONS: In old age, APOE genotype modulates the association between serum calcium levels and cognitive function. High serum calcium levels associate with worse cognitive function, especially in APOE epsilon4 allele carriers, but not in carriers of the epsilon2 allele.

Effects of dietary protein and energy levels on cow manure excretion and ammonia volatilization.

Adjusting dietary composition is considered an effective way to reduce nutrient losses to the environment. The effects of various dietary protein and energy levels on manure composition (Ca, Mg, K, Na, N, P, and pH) were studied by determining total and direct available (free) nutrient concentrations in 8 slurries obtained from a feeding trial. Furthermore, the effects of dietary changes on NH(3) volatilization from manure slurries were studied. Increasing the crude protein (CP) content of the feed (108 to 190 g/ kg of dry matter) resulted in an average increase in total N and P content of the slurries of 56 and 48%, respectively. Feeding the cows more energy (5,050 to 6,840 kJ/kg of dry matter) increased total N and P content of the slurries by 27 and 39%, respectively. Total ammoniacal nitrogen (TAN) amounted to 52 to 77% of the total N content present in manure slurries. A low protein content or a low energy content of the diets reduced TAN concentrations in the slurries by 43% (CP) or 25% (energy). Changes in the protein content or the energy content of the feed did not significantly affect the free:total ratios of Na, Ca, and Mg content of the slurries. In agreement with the calculated NH(3,aq) (aqueous) content, the total amount of NH(3) volatilized from manure slurries was much greater (on average 10 times greater) when the cows were fed greater levels of CP. Although the slurries contained more TAN when cows were fed diets richer in energy, NH(3) volatilization from the slurries was lower.

Progenitor cells isolated from the human heart: a potential cell source for regenerative therapy.

BACKGROUND: In recent years, resident cardiac progenitor cells have been identified in, and isolated from the rodent heart. These cells show the potential to form cardiomyocytes, smooth muscle cells, and endothelial cells in vitro and in vivo and could potentially be used as a source for cardiac repair. However, previously described cardiac progenitor cell populations show immature development and need co-culture with neonatal rat cardiomyocytes in order to differentiate in vitro. Here we describe the localisation, isolation, characterisation, and differentiation of cardiomyocyte progenitor cells (CMPCs) isolated from the human heart. METHODS: hCMPCs were identified in human hearts based on Sca-1 expression. These cells were isolated, and FACS, RT-PCR and immunocytochemistry were used to determine their baseline characteristics. Cardiomyogenic differentiation was induced by stimulation with 5-azacytidine. RESULTS: hCMPCs were localised within the atria, atrioventricular region, and epicardial layer of the foetal and adult human heart. In vitro, hCMPCs could be induced to differentiate into cardiomyocytes and formed spontaneously beating aggregates, without the need for co-culture with neonatal cardiomyocytes. CONCLUSION: The human heart harbours a pool of resident cardiomyocyte progenitor cells, which can be expanded and differentiated in vitro. These cells may provide a suitable source for cardiac regeneration cell therapy. (Neth Heart J 2008;16:163-9.).

Effects of cow diet on the microbial community and organic matter and nitrogen content of feces.

Knowledge of the effects of cow diet on manure composition is required to improve nutrient use efficiency and to decrease emissions of N to the environment. Therefore, we performed an experiment with nonlactating cows to determine the consequences of changes in cow rations for the chemical characteristics and the traits of the microbial community in the feces. In this experiment, 16 cows were fed 8 diets, differing in crude protein, neutral detergent fiber, starch, and net energy content. These differences were achieved by changing dietary ingredients or roughage to concentrate ratio. After an adaptation period of 3 wk, fecal material was collected and analyzed. Observed results were compared with simulated values using a mechanistic model that provides insight into the mechanisms involved in the effect of dietary variation on fecal composition. Feces produced on a high-fiber, low-protein diet had a high C:N ratio (>16) and had lower concentrations of both organic and inorganic N than feces on a low-fiber, high-protein diet. Fecal bacterial biomass concentration was highest in high-protein, high-energy diets. The fraction of inorganic N in the feces was not significantly different between the different feces. Microbial biomass in the feces ranged from 1,200 to 8,000 microg of C/g of dry matter (average: 3,700 microg of C/g of dry matter). Bacterial diversity was similar for all fecal materials, but the different protein levels in the feeding regimens induced changes in the community structure present in the different feces. The simulated total N content (N(total)) in the feces ranged from 1.0 to 1.5 times the observed concentrations, whereas the simulated C:N(total) of the feces ranged from 0.7 to 0.9 times the observed C:N(total). However, bacterial biomass C was not predicted satisfactorily (simulated values being on average 3 times higher than observed), giving rise to further discussion on the definition of microbial C in feces. Based on these observations, it was concluded that diet composition affected fecal chemical composition and microbial biomass. These changes may affect the nutrient use and efficiency of the manure. Because the present experiment used a limited number of dry cows and extreme diet regimens, extrapolation of results to other dairy cow situations should be done with care.

Volatilization of ammonia from manure as affected by manure additives, temperature and mixing.

Ammonia (NH(3)) volatilization decreases the N-nutrient value of livestock manure slurries and can lead to soil acidification and eutrophication problems. In this study the effect of three manure additives (Euro Mest-mix (Mx), Effective Micro-organisms (EM), and Agri-mest (Am)) on NH(3) volatilization at three temperatures (4, 20, and 35 degrees C) was investigated. The manufacturers claim that Mx contains absorbing clay minerals and that applying Am and EM to slurry will reduce nitrogen losses, most likely by enhancing the biodegradation of manure slurry. Furthermore, the effect of mixing slurry on NH(3) volatilization has been investigated. Ammonia volatilization increased with increasing temperature and mixing of the slurries. However, at 35 degrees C mixing of manure reduced NH(3) emissions compared to non-mixing, which is related to a reduced crust resistance to gaseous transport at higher temperatures for non-mixing. Moreover, mixing introduces oxygen into the anaerobic slurry environment which will slow down microbial activity. The use of additives did not change manure characteristics (pH, dry matter, N(total), N(mineral), C/N, and C/N(organic)) and did not result in a significant (p<0.05) decrease in NH(3) emissions, except that at 4 degrees C and no mixing a significant decrease of 34% in NH(3) volatilization was observed, when Am and EM together, were applied to slurry.

Heavy metal concentrations in soil and earthworms in a floodplain grassland.

We determined accumulated heavy metal concentrations (Cd, Pb, Cu, Zn) of earthworms in moderately contaminated floodplain soils. Both soil and mature earthworms were sampled before and after flooding and earthworm species were identified to understand species specific differences in bioconcentration. Accumulated metal concentrations in floodplain earthworms differed before and after flooding. Differences in uptake and elimination mechanisms, in food choice and living habitat of the different earthworm species and changes in speciation of the heavy metals are possible causes for this observation. Regression equations taken from literature, that relate metal accumulation by earthworms in floodplains as a function of metal concentration in soil, performed well when all species specific data were combined in an average accumulation, but did not address differences in accumulation between earthworm species.

Comparison of Bobath based and movement science based treatment for stroke: a randomised controlled trial.

OBJECTIVES: Bobath based (BB) and movement science based (MSB) physiotherapy interventions are widely used for patients after stroke. There is little evidence to suggest which is most effective. This single-blind randomised controlled trial evaluated the effect of these treatments on movement abilities and functional independence. METHODS: A total of 120 patients admitted to a stroke rehabilitation ward were randomised into two treatment groups to receive either BB or MSB treatment. Primary outcome measures were the Rivermead Motor Assessment and the Motor Assessment Scale. Secondary measures assessed functional independence, walking speed, arm function, muscle tone, and sensation. Measures were performed by a blinded assessor at baseline, and then at 1, 3, and 6 months after baseline. Analysis of serial measurements was performed to compare outcomes between the groups by calculating the area under the curve (AUC) and inserting AUC values into Mann-Whitney U tests. RESULTS: Comparison between groups showed no significant difference for any outcome measures. Significance values for the Rivermead Motor Assessment ranged from p = 0.23 to p = 0.97 and for the Motor Assessment Scale from p = 0.29 to p = 0.87. CONCLUSIONS: There were no significant differences in movement abilities or functional independence between patients receiving a BB or an MSB intervention. Therefore the study did not show that one approach was more effective than the other in the treatment of stroke patients.

Early, current and past pet ownership: associations with sensitization, bronchial responsiveness and allergic symptoms in school children.

BACKGROUND: Studies have suggested that early contact with pets may prevent the development of allergy and asthma. OBJECTIVE: To study the association between early, current and past pet ownership and sensitization, bronchial responsiveness and allergic symptoms in school children. METHODS: A population of almost 3000 primary school children was investigated using protocols of the International Study on Asthma and Allergies in Childhood (ISAAC). Allergic symptoms were measured using the parent-completed ISAAC questionnaire. Sensitization to common allergens was measured using skin prick tests (SPT)s and/or serum immunoglobulin (Ig)E determinations. Bronchial responsiveness was tested using a hypertonic saline challenge. Pet ownership was investigated by questionnaire. Current, past and early exposure to pets was documented separately for cats, dogs, rodents and birds. The data on current, past and early pet exposure were then related to allergic symptoms, sensitization and bronchial responsiveness. RESULTS: Among children currently exposed to pets, there was significantly less sensitization to cat (odds ratio (OR) = 0.69) and dog (OR = 0.63) allergens, indoor allergens in general (OR = 0.64), and outdoor allergens (OR = 0.60) compared to children who never had pets in the home. There was also less hayfever (OR = 0.66) and rhinitis (OR = 0.76). In contrast, wheeze, asthma and bronchial responsiveness were not associated with current pet ownership. Odds ratios associated with past pet ownership were generally above unity, and significant for asthma in the adjusted analysis (OR = 1.85), suggesting selective avoidance in families with sensitized and/or symptomatic children. Pet ownership in the first two years of life only showed an inverse association with sensitization to pollen: OR = 0.71 for having had furry or feathery pets in general in the first two years of life, and OR = 0.73 for having had cats and/or dogs in the first two years of life, compared to not having had pets in the first two years of life. CONCLUSION: These results suggest that the inverse association between current pet ownership and sensitization and hayfever symptoms was partly due to the removal of pets in families with sensitized and/or symptomatic children. Pet ownership in the first two years of life only seemed to offer some protection against sensitization to pollen.

Comparison of the content of two physiotherapy approaches for stroke.

OBJECTIVE: To identify similarities and differences between a Bobath-based (BB) and a movement science-based (MSB) approach. DESIGN: Direct observation by a trained observer was used to record behaviours during treatments. SETTING: An acute stroke ward. SUBJECTS: Twenty-two stroke patients. INTERVENTIONS: Behaviours were recorded during 12 treatment sessions by three therapists, for each treatment approach. Physical and communication behaviours were recorded in pre-defined categories. The equipment used was recorded and a semi-structured interview conducted with the therapist after treatment to identify follow-up actions by the therapist. MAIN OUTCOME MEASURES: Frequency of occurrence of each category was compared between the approaches. RESULTS: Treatment in the BB group contained more social conversation (p = 0.004), and more use of physiotherapy equipment (p = 0.02) and a physiotherapy assistant (p = 0.01). In the MSB group there was more detailed feedback given to the patient (p = 0.002) more use of everyday objects in training (p = 0.001), therapists more frequently listed specific components as the patient's main problems (p = 0.003) and relatives were involved more in positioning to stretch muscles (p = 0.03). Training walking was given more emphasis in the BB group and training of sit-to-stand in the MSB group. CONCLUSIONS: The study indicates that there are differences in content between the Bobath-based and movement science-based approaches to treatment.

Personal and outdoor nitrogen dioxide concentrations in relation to degree of urbanization and traffic density.

To assess differences in exposure to air pollution from traffic in relation to degree of urbanization and traffic density, we measured personal and home outdoor nitrogen dioxide (NO(2)) concentrations for 241 children from six different primary schools in the Netherlands. Three schools were situated in areas with varying degrees of urbanization (very urban, fairly urban, and nonurban) and three other schools were located near highways with varying traffic density (very busy, fairly busy, and not busy). Weekly averaged measurements were conducted during four different seasons. Simultaneously, indoor and outdoor measurements were conducted at the schools. Personal and outdoor NO(2) concentrations differed significantly among children attending schools in areas with different degrees of urbanization and among children attending schools in areas close to highways with different traffic densities. For the children living near highways, personal and outdoor NO(2) concentrations also significantly decreased with increasing distance of the home address to the highway. Differences in personal exposures between children from the different schools remained present and significant after adjusting for indoor sources of NO(2). This study has shown that personal and outdoor NO(2) concentrations are influenced significantly by the degree of urbanization of the city district and by the traffic density of and distance to a nearby highway. Because NO(2) can be considered a marker for air pollution from traffic, the more easily measured variables degree of urbanization, traffic density, and distance to a nearby highway can all be used to estimate exposure to traffic-related air pollution.

The structural role of the copper-coordinating and surface-exposed histidine residue in the blue copper protein azurin.

Copper K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and (15)N NMR relaxation studies were performed on samples of a variant azurin in which the surface-exposed histidine ligand of the copper atom (His117) has been replaced by glycine. The experiments were performed to probe the structure of the active site and the protein dynamics. The cavity in the protein structure created by the His-->Gly replacement could be filled by external ligands, which can either restore the spectroscopic properties of the original type-1 copper site or create a new type-2 copper site. The binding of external ligands occurs only when the copper atom is in its oxidised state. In the reduced form, the binding is abolished. From the EXAFS experiments, it is concluded that for the oxidised type-1 copper sites the protein plus external ligand (L) provide an NSS*L donor set deriving from His46, Cys112, Met121 and the external ligand. The type-2 copper site features an S(N/O)(3) donor set in which the S-donor derives from Cys112, one N-donor from His46 and the remaining two N or O donors from one or more external ligands. Upon reduction of the type-1 as well as the type-2 site, the external ligand drops out of the copper site and the coordination reduces to 3-fold with an SS*N donor set deriving from His46, Cys112 and Met121. The Cu-S(delta)(Met) distance is reduced from about 3.2 to 2.3 A. Analysis of the NMR data shows that the hydrophobic patch around His117 has gained fluxionality when compared to wild-type azurin, which may explain why the His117Gly variant is able to accommodate a variety of external ligands of different sizes and with different chelating properties. On the other hand, the structure and dynamics of the beta-sandwich, which comprises the main body of the protein, is only slightly affected by the mutation. The unusually high reduction potential of the His117Gly azurin is discussed in light of the present results.

Field research for the authorisation of pesticides.

On request of the Dutch government a committee of the Health Council of the Netherlands has reviewed the role that results of field research in its broadest sense (i.e., including multi-species toxicity tests in the laboratory, research on model ecosystems et cetera) can play in ecotoxicological risk assessment for the authorisation of pesticides. The Committee believes that field research can provide valuable additional data about the exposure of non-target organisms and the resultant effects at population, community and ecosystem level. However, it frequently is unclear how these data might be used in reaching a decision about authorisation. To solve this problem, it is necessary to specify what is understood by "unacceptable damage". Both more clearly formulated protection goals of the government and a better understanding of the ecological significance of effects are needed to clarify this. Furthermore, the Committee points out that the statistical power of field trials must be sufficient to allow for the detection of changes that might be regarded as ecologically relevant. Finally, it recommends keeping a finger on the pulse in relation to authorised pesticides by monitoring their presence in environmental compartments and by investigating their role in suddenly occurring mortality among conspicuous animal species, such as birds, fish and honeybees. This kind of research forms a safety net for substances that have been wrongly authorised.

Traffic related air pollution in city districts near motorways.

Traffic related air pollution near major motorways was measured and results are presented.