Environmental impacts of nitrogen emissions in China and the role of policies in emission reduction

Atmospheric reactive nitrogen (N_r) has been a cause of serious environmental pollution in China. Historically, China used too little N_r in its agriculture to feed its population. However, with the rapid increase in N fertilizer use for food production and fossil fuel consumption for energy supply over the last four decades, increasing gaseous N_r species (e.g. NH₃ and NO_x) have been emitted to the atmosphere and then deposited as wet and dry deposition, with adverse impacts on air, water and soil quality as well as plant biodiversity and human health. This paper reviews the issues associated with this in a holistic way. The emissions, deposition, impacts, actions and regulations for the mitigation of atmospheric N_r are discussed systematically. Both NH₃ and NO_x make major contributions to environmental pollution but especially to the formation of secondary fine particulate matter (PM_2.5), which impacts human health and light scattering (haze). In addition, atmospheric deposition of NH₃ and NO_x causes adverse impacts on terrestrial and aquatic ecosystems due to acidification and eutrophication. Regulations and practices introduced by China that meet the urgent need to reduce N_r emissions are explained and resulting effects on emissions are discussed. Recommendations for improving future N management for achieving 'win-win' outcomes for Chinese agricultural production and food supply, and human and environmental health, are described. This article is part of a discussion meeting issue 'Air quality, past present and future'.

A randomized controlled trial of a walking training with simultaneous cognitive demand (dual-task) in chronic stroke

BACKGROUND AND PURPOSE

The aim was to evaluate the tolerability of, adherence to and efficacy of a community walking training programme with simultaneous cognitive demand (dual-task) compared to a control walking training programme without cognitive distraction.

METHODS

Adult stroke survivors at least 6 months after stroke with a visibly obvious gait abnormality or reduced 2-min walk distance were included in a two-arm parallel randomized controlled trial of complex intervention with blinded assessments. Participants received a 10 week, bi-weekly, 30 min treadmill programme at an aerobic training intensity (55%-85% heart rate maximum), either with or without simultaneous cognitive demands. Outcome was measured at 0, 11 and 22 weeks. The primary assessment involved 2-min walk tests with and without cognitive distraction to investigate the dual-task effect on walking and cognition; secondary results were the Short Form Health Survey 36, EuroQol-5D-5L, the Physical Activity Scale for the Elderly (PASE) and step activity.

RESULTS

Fifty stroke patients were included; 43 received allocated training and 45 completed all assessments. The experimental group (n = 26) increased their mean (SD) 2-min walking distance from 90.7 (8.2) to 103.5 (8.2) m, compared with 86.7 (8.5) to 92.8 (8.6) m in the control group, and their PASE score from 74.3 (9.1) to 89.9 (9.4), compared with 94.7 (9.4) to 77.3 (9.9) in the control group. Statistically, only the change in the PASE differed between the groups (P = 0.029), with the dual-task group improving more. There were no differences in other measures.

CONCLUSIONS

Walking with specific additional cognitive distraction (dual-task training) might increase activity more over 12 weeks, but the data are not conclusive.

Interobserver agreement and diagnostic performance of individual MRI criteria for diagnosis of placental adhesion disorders

AIM

To assess the diagnostic accuracy of several criteria for the diagnosis of placental adhesion disorder (PAD) on magnetic resonance imaging (MRI) and to assess interobserver agreement and reader accuracy based on years of interpretive experience.

MATERIALS AND METHODS

Blinded evaluation of the placental MRI studies of 28 randomly selected women, 18 with PADs and 10 without PADs, was undertaken by three radiologists with 10, 5, and 2 years' experience in placental MRI interpretation. The presence of placenta praevia, dark intraplacental bands, heterogeneity, uterine bulging, "shaggy dog" appearance of the uterine serosa, subjective impression of extraplacental invasion, and dark intraplacental bands on diffusion-weighted imaging were assessed. Placental histology was reviewed blinded to the original reports and to MRI interpretation and this, along with clinical information at the time of delivery, formed the reference standard.

RESULTS

Dark intraplacental bands on T2-weighted imaging were the most sensitive and specific as well as the most agreed upon (kappa=0.7) criterion for PAD for the three readers. Assessment of uterine bulging (kappa=0.42) and placental heterogeneity (kappa=0.48) did not improve diagnostic accuracy. DWI improved sensitivity but decreased specificity for the least experienced reader and did not change sensitivity or specificity for the more experienced readers.

CONCLUSION

Assessment of the placenta for dark bands is the most sensitive, specific, and reproducible criterion for diagnosis of PADs using MRI.

Alterations in the metabolic and cardiorespiratory response to exercise in Huntington's Disease

BACKGROUND

Limited data suggests that an altered metabolic and cardiorespiratory exercise response may affect exercise performance in individuals with Huntington's disease (HD). There is no clear exploration of the response in individuals at different stages of the disease or in relation to genetic markers. This study aimed to examine the exercise response and recovery of HD participants, and the relationship to genetic and clinical markers.

METHOD

HD gene-positive participants (n = 31; 9 pre-manifest; 22 manifest HD) and a healthy control group (n = 29) performed an incremental exercise test until exhaustion. Performance, cardiorespiratory, metabolic and perceptual responses to exercise were determined from a maximal cycle ergometer test throughout the exercise test and during a recovery period.

RESULTS

During sub-maximal exercise, metabolic (lactate levels, oxygen uptake) and cardiorespiratory markers (heart rate) were elevated in HD participants compared to controls. Lactate elevation was specific to pre-manifest HD participants. Work capacity was reduced in both pre-manifest and manifest HD participants with tests terminated with no difference in metabolic, perceptual or cardiorespiratory markers. Submaximal oxygen uptake was correlated with motor score, whilst peak measures were unrelated to genetic or clinical markers. Heart rate recovery was attenuated in pre-manifest and manifest HD participants.

CONCLUSIONS

Our findings confirm metabolic and cardiorespiratory deficits reduce exercise performance and affect recovery from an early stage in HD, with submaximal deficits related to phenotypic expression. Exercise capacity appears to be limited by an altered movement economy, thus clinicians should consider an altered exercise response and recovery may affect prescription in HD.

A protocol for a randomised double-blind placebo-controlled feasibility study to determine whether the daily consumption of flavonoid-rich pure cocoa has the potential to reduce fatigue in people with relapsing and remitting multiple sclerosis (RRMS)

Background

Dietary interventions including consumption of flavonoids, plant compounds found in certain foods, may have the ability to improve fatigue. However, to date, no well-designed intervention studies assessing the role of flavonoid consumption for fatigue management in people with MS (pwMS) have been performed. The hypothesis is that the consumption of a flavonoid-rich pure cocoa beverage will reduce fatigue in pwMS. The aim of this study is to determine the feasibility and potential outcome of running a trial to evaluate this hypothesis.

Methods

Using a randomised (1:1) double-blind placebo-controlled feasibility study, 40 men and women (20 in each trial arm) with a recent diagnosis (< 10 years) of relapsing and remitting MS (RRMS) and who are over 18 years of age will be recruited from neurology clinics and throughout the Thames Valley community. During a 6-week nutrition intervention period, participants will consume the cocoa beverage, high flavonoid or low flavonoid content, at breakfast daily. At baseline, demographic factors and disease-related factors will be assessed. Fatigue, activity and quality of life, in addition to other measures, will be taken at three visits (baseline, week 3 and week 6) in a university setting by a researcher blinded to group membership. Feasibility and fidelity will be assessed through recruitment and retention, adherence and a quantitative process evaluation at the end of the trial.

We will describe demographic factors (age, gender, level of education) as well as disease-related factors (disease burden scores, length of time diagnosed with MS) and cognitive assessment, depression and quality of life and general physical activity in order to characterise participants and determine possible mediators to identify the processes by which the intervention may bring about change. Feasibility (recruitment, safety, feasibility of implementation of the intervention and evaluation, protocol adherence and data completion) and potential for benefit (estimates of effect size and variability) will be determined to inform future planned studies. Results will be presented using point estimates, 95% confidence intervals and p values. Primary statistical analysis will be on an intention-to-treat basis and will use the complete case data set.

Discussion

We propose that a flavonoid-enriched cocoa beverage for the management of fatigue will be well received by participants. Further, if it is implemented early in the disease course of people diagnosed with RRMS, it will improve mobility and functioning by modifying fatigue.

Trial registration

Registered with ISRCTN Registry. Trial registration No: ISRCTN69897291; Date April 2016

Flavonoid rich dark cocoa may improve fatigue in people with multiple sclerosis, yet has no effect on glycaemic response: An exploratory trial

CONTEXT

Current research suggests that dark cocoa may reduce fatigue; however, the effect on fatigue in people with MS (pwMS) has never been established. The objective of this feasibility study was to explore the acute effect of high flavonoid cocoa on measures of fatigue and glycaemic response.

METHODS

This was a randomised crossover participant blind exploratory study in 12 participants (2 male and 10 female) with MS-related fatigue (>4 on the Fatigue Severity Scale; FSS). After fasting overnight, participants consumed the high flavonoid cocoa drink (350 mg gallic acid equivalents {GAE}/g) or a low flavonoid cocoa control (120 mg GAE/g), consuming the alternative drink on the next visit. Fatigue was self-reported on a 100 mm visual analogue scale at 30-min time intervals for 2 h post cocoa consumption and every 2 h for the rest of the day. Fatigability was monitored using a 6 min walk test (6MWT) at the end of the visit (2 h), and activity monitors worn for 24 h commencing at 12 noon on the day of testing. The feasibility of performing the trial including outcome measures was documented.

RESULTS

A moderate effect was found in self-reported fatigue throughout the day in favour of the high flavonoid group (Cohen's d 0.32, 95% non-central t CI -0.57 to 1.20). Fatigability measures did not change. Participants consumed and enjoyed the cocoa, all participants completed the study and outcome measures were accepted.

CONCLUSION

The results of this study support further trials to investigate the feasibility and efficacy of pure cocoa as a dietary supplement for fatigue in pwMS.

Exercise testing and training in people with Huntington's disease

OBJECTIVE

To explore exercise response in people with Huntington's disease (HD).

DESIGN

Experimental observational study with a randomly allocated subgroup before/after interventional study.

SETTING

Community.

SUBJECTS

People with HD (n=30) and a healthy comparator group (n=20). Thirteen people from the HD group were randomly allocated to an exercise training program.

MAIN MEASURES

Heart rate (HR) and perceived exertion on the Borg-CR10 scale (RPE) during a submaximal cycle ergometer exercise test (three minute unloaded and nine minute 65%-75%HRmaximum phase). Expired air and lactate measures were available for 8 people with HD during the exercise.

INTERVENTION

A 12 week gym and home walking exercise programme (n=13).

RESULTS

People with HD achieved a lower work rate at nine minutes (82±42(0-195) v 107±35(50 -185) Watts (p<0.05)), but higher RPE at both three (3±2(0-7) v 1±1(0-4)) and nine minutes (7±3(1-10) v 5± 2(2-9)) both p<0.01, compared to the healthy group and did not achieve a steady state HR during unloaded cycling. People with HD also demonstrated higher than expected lactate at three 2.5±2.5(1.1-8)mmo.L-1 and nine 3.8±1.9(1.2-6.6)mmo.L-1 minutes and respiratory exchange ratio at three 0.78±0.03 (0.74-0.81) and nine minutes 0.94±0.11(0.81-1.15). After exercise training there were no changes observed in HR or RPE responses during the exercise test.

CONCLUSIONS

There was a large variability in the observed metabolic and physiological responses to exercise in people with HD. The observed exercise responses suggest that altered exercise prescription parameters may be required for people with HD and that exercise response and factors' affecting this requires further investigation.

Cardiovascular adaptation in people with multiple sclerosis following a twelve week exercise programme suggest deconditioning rather than autonomic dysfunction caused by the disease. Results from a randomized controlled trial

BACKGROUND

Guidelines for optimal exercise doses in people with multiple sclerosis (MS) have to be established. We need to ascertain the basic physiological and perceptual response and adaptation to different exercise doses in this clinical population.

AIM

The aim of this paper was to explore the response during maximal and sub-maximal exercise in people with MS prior to and following two different twelve week exercise programmes.

DESIGN

Sub-analysis of per protocol exercise data of a two group, single blinded, randomised control trial.

SETTING

Multicentre (community leisure and rehabilitation centres).

POPULATION

Participants with MS assigned to a continuous (N.=12; mean±SE age=52.3±2.08; Barthel index median & range=19&13-20) or interval (N.=9; mean±SE age=49.3±3.5; Barthel index median & range=19&18-20) exercise programme.

METHODS

Cardiovascular, respiratory and perceptual exercise response and adaption was measured at maximal and sub-maximal levels of physical exercise prior to and following a twelve week exercise programme, delivered at different intensities.

RESULTS

Irrespective of the type of exercise programme followed, there was a significant increase in peak power (z=-1.98; P=0.05) and normalised oxygen uptake during unloaded cycling (z =-2.00; P=0.05). At discharge from the exercise programmes, the cardiovascular response to sub-maximal exercise had significantly changed (t(360) =-4.62; p<0.01).

CONCLUSION

The response in people with MS at maximal and sub-maximal levels of physical exercise following a twelve week programme is analogous to non-diseased adults.

CLINICAL REHABILITATION IMPACT

Cardiovascular adaptation in people with MS following a twelve week exercise programme suggests deconditioning rather than autonomic dysfunction caused by the disease.

Enteral nutrition by nasojejunal tube in hyperemesis gravidarum

We describe two cases in which self-propelling, blind placed nasojejunal tubes were placed in severe hyperemesis gravidarum. This method provides an alternative to parenteral nutrition and to percutaneous endoscopic tubes, is well tolerated, cost effective and with a low rate of complication. Both mothers were given nutritional support at home, had normal subsequent pregnancies and normal babies.

Validation of the saliva-based H. pylori test, heliSAL, and its use in prevalence surveys

The saliva-based H. pylori test, HeliSAL, is insufficiently accurate for use in the clinical setting. However, its ease of use and non-invasiveness make it attractive for population-based studies of the epidemiology of H. pylori. We validated HeliSAL, and comment here on its usefulness in prevalence surveys. One hundred and ninety-six patients receiving endoscopy at a clinic in New Zealand provided saliva samples for H. pylori assessment, which were compared to CLOtest (Delta West Pty Ltd, Western Australia) as a gold standard measure. Nineteen percent were truly H. pylori positive, 41% were positive according to HeliSAL. Test sensitivity was 74% and specificity was 67%. While HeliSAL is not well suited for the clinical diagnosis of H. pylori infection, it may be useful for large-scale prevalence surveys because, provided it is validated locally, mathematical adjustment can be made for misclassification. Being inexpensive, non-invasive, and easily stored and handled, HeliSAL may be a valuable tool for studies of the epidemiology of H. pylori.

The 'cut and push' method of percutaneous endoscopic gastrostomy tube removal

BACKGROUND AND AIMS

The standard method of removing percutaneous endoscopic gastrostomy tubes is by gastroscopy. This has implications for endoscopy time and resources, and we believe is not always necessary. Depending on the type of percutaneous endoscopic gastrostomy tube used we often used the 'cut and push' method. This involves cutting the catheter at skin level and allowing the tube and internal bumper to spontaneously pass. The cut and push method also represents a considerable resource saving compared to the endoscopic method that we think warrants further discussion.

METHOD

We reviewed all the files of the percutaneous endoscopic gastrostomy tubes removed in our unit over the last 4 years.

RESULTS

During the period of July 1995 to July 1999, we have inserted 384 percutaneous endoscopic gastrostomy tubes. Seven tubes have been removed endoscopically and 73 tubes have been removed with the cut and push method. Only two possible complications have been recorded (2.7%).

CONCLUSIONS

We believe that we have provided further evidence that percutaneous endoscopic gastrostomy tubes can be removed safely using the cut and push method. Patients who are often frail and who have multiple medical problems are saved an often-long journey to the endoscopy unit as well as the hazards of an endoscopy. The saving in resources in what is already an overworked system by not performing endoscopies is also considerable.

Screening protocol for Torulopsis (Candida) glabrata

A screening test has been developed for the presumptive identification of Torulopsis (Candida) glabrata from other common clinical isolates of yeast-like fungi. An interlaboratory comparison of a protocol consisting of morphology on cornmeal Tween 80 agar and trehalose fermentation at 42 degrees C was successful in differentiating T. glabrata from other taxa that are frequent or possible clinical isolates. The screening results for 517 clinical yeast isolates, 241 of which were T. glabrata, were compared with their final identification via commercial systems (API20C Yeast Identification System [bioMERIEUX, Hazelwood, Mo.] and Rapid Yeast Identification Panel [Dade Microscan, Sacramento, Calif.]). The trehalose screening test has a sensitivity and a specificity of 97.8 and 95.8%, respectively, and a positive predictive value of 97.4% and a negative predictive value of 96.5%. Overall, the trehalose screen had an efficiency rating of 93.9% for ruling in or out T. glabrata. Since T. glabrata represents a substantial part of the workload in a clinical laboratory, a significant reduction in direct and indirect costs should be realized.

The risk of infection from Giardia lamblia due to drinking water supply, use of water, and latrines among preschool children in rural Lesotho

Stool samples were collected from 267 rural, preschool children in four districts in Lesotho during October-November, 1984. Sixty-three children (23.6%) were tested positive for Giardia lamblia, the most commonly recovered parasite from stool samples. The use of low amounts of water for personal hygiene was associated significantly with having G. lamblia (OR = 2.42), but the use of traditional, non-improved drinking water sources (OR = 1.38) or lack of latrines (OR = 0.94) was not. Although G. lamblia may be primarily waterborne in developed countries, the amount of water that is used for personal and domestic hygiene may be more important than the quality of drinking water in developing countries. Other risk factors that were identified to be associated significantly with having or not having Giardia were child older than 24 months (OR = 6.79), mother less than 20 years of age (OR = 5.18), residing in Mohales Hoek district (OR = 2.33), and possessing several agricultural tools (OR = 0.70).

Perinatal mortality in Southland: an ongoing review

A review of Southland's perinatal mortality was undertaken from 1978 to 1983 and included 124 deaths with a postmortem rate of 90%. The perinatal mortality rate has continued to fall during this period, and has more than halved since 1971. Prematurity remains the single most important factor, and there are still a large number of avoidable deaths. Eighty percent of confinements are attended solely by general practitioner obstetricians.

Plasma timolol levels and systolic time intervals

The beta-blocking potency of timolol was compared with that of propranolol under steady-state conditions in eight healthy subjects. The effects on systolic time intervals in healthy subjects and patients (n = 6) with coronary artery disease were evaluated in relation to varying timolol dose schedules and plasma concentrations. The beta-blocking potency was assessed by the inhibition of exercise-induced tachycardia. Timolol was eight times as potent as propranolol. There was wide between-patient variation (2.6 to 13.8) in timolol plasma concentration, and correlation between dose and peak (r = 0.61, p < 0.01) or nadir (r = 0.5 p < 0.01). There was a relatively weak correlation between timolol plasma concentration and degree of beta-blockade (r = 0.45, p < 0.05) and a linear correlation with dose (r = 0.98, p < 0.001). In healthy subjects timolol and propranolol had variable effects on systolic time intervals but in patients with coronary artery disease equipotent doses prolonged the preejection period, isovolumetric contraction time, and the ratio of the preejection period over the left ventricular ejection time. In patients as well as in normal subjects, the data indicated considerable beta-blocking effects for both drugs at the end of a 12-hourly dosing schedule, suggesting that twice-daily timolol and propranolol may be clinically practical.

Hemodynamic effects of intravenous timolol in coronary artery disease

The hemodynamic effects of intravenous timolol were evaluated in 20 patients with coronary artery disease during diagnostic cardiac catheterization. The threshold dose of 0.25 mg reduced heart rate and cardiac index by 15% (p less than 0.05), left ventricular work index by 21% (p less than 0.05), and left ventricular dp/dt by 16% (p less than 0.05) while increasing left ventricular end-diastolic pressure by 49% (p less than 0.01), mean pulmonary arterial pressure by 17% (p less than 0.01), and systemic vascular resistance by 16% (NS). Larger doses (0.5 mg and 1.0 mg) induced similar responses with a greater effect on systemic vascular resistance (+22%, p less than 0.01, and +31%, p less than 0.001). The mean arterial pressure and stroke volumes were not affected by timolol. Peak effects, occurring at about 10 min after drug injection, did not correlate with plasma levels. The overall hemodynamic effects of timolol were similar to those reported for equipotent doses of propranolol and could be accounted for by the beta-adrenoceptor blocking activity.

Mexiletine: a review of its pharmacological properties and therapeutic efficacy in arrhythmias

Mexiletine is a new local anaesthetic antiarrhythmic agent whose chemical structure and electrophysiological properties closely resemble those of lignocaine although its anticonvulsant and pharmacokinetic properties differ from that drug. Unlike lignocaine (lidocaine) it is active following oral administration with a plasma half-life varying between 8 and 20 hours so that it can be administered twice or three times daily to sustain therapeutic plasma levels. The drug is effective when given intravenously or by the oral route in controlling ventricular arrhythmias especially following acute myocardial infarction but the side effects are greater during parenteral administration. Side effects during chronic oral therapy with mexiletine have not posed a serious problem. Mexiletine has the pharmacodynamic and pharmacokinetic properties of an agent suitable for the chronic oral prophylaxis of serious ventricular arrhythmias in patients with ischaemic heart disease.