Multimodal Preventive Trial for Alzheimer's Disease: MIND-ADmini Pilot Trial Study Design and Progress.

BACKGROUND: Interventions simultaneously targeting multiple risk factors and mechanisms are most likely to be effective in preventing cognitive impairment. This was indicated in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) testing a multidomain lifestyle intervention among at-risk individuals. The importance of medical food at the early symptomatic disease stage, prodromal Alzheimer's disease (AD), was emphasized in the LipiDiDiet trial. The feasibility and effects of multimodal interventions in prodromal AD are unclear. OBJECTIVES: To evaluate the feasibility of an adapted FINGER-based multimodal lifestyle intervention, with or without medical food, among individuals with prodromal AD. METHODS: MIND-ADmini is a multinational proof-of-concept 6-month randomized controlled trial (RCT), with four trial sites (Sweden, Finland, Germany, France). The trial targeted individuals with prodromal AD defined using the International Working Group-1 criteria, and with vascular or lifestyle-related risk factors. The parallel-group RCT includes three arms: 1) multimodal lifestyle intervention (nutritional guidance, exercise, cognitive training, vascular/metabolic risk management and social stimulation); 2) multimodal lifestyle intervention+medical food (Fortasyn Connect); and 3) regular health advice/care (control group). Primary outcomes are feasibility and adherence. Secondary outcomes are adherence to the individual intervention domains and healthy lifestyle changes. RESULTS: Screening began on 28 September 2017 and was completed on 21 May 2019. Altogether 93 participants were randomized and enrolled. The intervention proceeded as planned. CONCLUSIONS: For the first time, this pilot trial tests the feasibility and adherence to a multimodal lifestyle intervention, alone or combined with medical food, among individuals with prodromal AD. It can serve as a model for combination therapy trials (non-pharma, nutrition-based and/or pharmacological interventions).

The Effect of Multidomain Interventions on Global Cognition, Symptoms of Depression and Apathy - A Pooled Analysis of Two Randomized Controlled Trials.

BACKGROUND: Cardiovascular risk factors and lifestyle factors are associated with an increased risk of cognitive decline and dementia in observational studies, and have been targeted by multidomain interventions. OBJECTIVES: We pooled individual participant data from two multi-domain intervention trials on cognitive function and symptoms of depression to increase power and facilitate subgroup analyses. DESIGN: Pooled analysis of individual participant data. SETTING: Prevention of Dementia by Intensive Vascular Care trial (preDIVA) and Multidomain Alzheimer Preventive Trial (MAPT). PARTICIPANTS: Community-dwelling individuals, free from dementia at baseline. INTERVENTION: Multidomain interventions focused on cardiovascular and lifestyle related risk factors. MEASUREMENTS: Data on cognitive functioning, depressive symptoms and apathy were collected at baseline, 2 years and 3-4 years of follow-up as available per study. We analyzed crude scores with linear mixed models for overall cognitive function (Mini Mental State Examination [MMSE]), and symptoms of depression and apathy (15-item Geriatric Depression Scale). Prespecified subgroup analyses were performed for sex, educational level, baseline MMSE <26, history of hypertension, and history of stroke, myocardial infarction and/or diabetes mellitus. RESULTS: We included 4162 individuals (median age 74 years, IQR 72, 76) with a median follow-up duration of 3.7 years (IQR 3.0 to 4.1 years). No differences between intervention and control groups were observed on change in cognitive functioning scores and symptoms of depression and apathy scores in the pooled study population. The MMSE declined less in the intervention groups in those with MMSE <26 at baseline (N=250; MD: 0.84; 95%CI: 0.15 to 1.54; p<0.001). CONCLUSIONS: We found no conclusive evidence that multidomain interventions reduce the risk of global cognitive decline, symptoms of depression or apathy in a mixed older population. Our results suggest that these interventions may be more effective in those with lower baseline cognitive functioning. Extended follow-up for dementia occurrence is important to inform on the potential long-term effects of multidomain interventions.

The Cost-Effectiveness of Three Prevention Strategies in Alzheimer's Disease: Results from the Multidomain Alzheimer Preventive Trial (MAPT).

BACKGROUND: To date, no curative treatment is available for Alzheimer's disease (AD). Therefore, efforts should focus on prevention strategies to improve the efficiency of healthcare systems. OBJECTIVE: Our aim was to assess the cost-effectiveness of three preventive strategies for AD compared to a placebo. DESIGN: The Multidomain Alzheimer Preventive Trial (MAPT) study was a multicenter, randomized, placebo-controlled superiority trial with four parallel groups, including three intervention groups (one group with Multidomain Intervention (MI) plus a placebo, one group with Polyunsaturated Fatty Acids (PFA), one group with a combination of PFA and MI) and one placebo group. SETTING: Participants were recruited and included in 13 memory centers in France and Monaco. PARTICIPANTS: Community-dwelling subject aged 70 years and older were followed during 3 years. INTERVENTIONS: We used data from the MAPT study which aims to test the efficacy of a MI along PFA, the MI plus a placebo, PFA alone, or a placebo alone. MEASUREMENT: Direct medical and non-medical costs were calculated from a payer's perspective during the 3 years of follow-up. The base case incremental Cost-Effectiveness Ratio (ICER) represents the cost per improved cognitive Z-score point. Sensitivity analyses were performed using different interpretation of the effectiveness criteria. RESULTS: Analyses were conducted on 1,525 participants. The ICER at year 3 that compares the MI + PFA and the MI alone to the placebo amounted to €21,443 and €21,543 respectively, per improved Z score point. PFA alone amounted to €111,720 per improved Z score point. CONCLUSION: Our study shows that ICERS of PFA combined with MI and MI alone amounted to €21,443 and €21,543 respectively per improved Z score point compared to the placebo and are below the WTP of €50,000 while the ICER of PFA alone amounted to €111,720 per improved Z score point. This information may help decision makers and serve as a basis for the implementation of a lifetime decision analytic model.

Cortical ß-Amyloid in Older Adults Is Associated with Multidomain Interventions with and without Omega 3 Polyunsaturated Fatty Acid Supplementation.

Multidomain lifestyle interventions (including combinations of physical exercise, cognitive training and nutritional guidance) are attracting increasing research attention for reducing the risk of Alzheimer's disease (AD). Here we examined for the first time the cross-sectional relationship between cortical ß-amyloid (Aß) and multidomain lifestyle interventions (nutritional and exercise counselling and cognitive training), omega 3 polyunsaturated fatty acid (n-3 PUFA) supplementation or their combination in 269 participants of the Multidomain Alzheimer Preventive Trial (MAPT). In adjusted multiple linear regression models, compared to the control group (receiving placebo alone), cortical Aß, measured once during follow-up (mean 512.7 ± 249.6 days post-baseline), was significantly lower in the groups receiving multidomain lifestyle intervention + placebo (mean difference, -0.088, 95 % CI, -0.148,-0.029, p = 0.004) or multidomain lifestyle intervention + n-3 PUFA (-0.100, 95 % CI, -0.160,-0.041, p = 0.001), but there was no difference in the n-3 PUFA supplementation alone group (-0.011, 95 % CI, -0.072,0.051, p = 0.729). Secondary analysis provided mixed results. Our findings suggest that multidomain interventions both with and without n-3 PUFA supplementation might be associated with lower cerebral Aß. Future trials should investigate if such multidomain lifestyle interventions are causally associated with a reduction or the prevention of the accumulation of cerebral Aß.

Defining the Optimal Target Population for Trials of Polyunsaturated Fatty Acid Supplementation Using the Erythrocyte Omega-3 Index: A Step Towards Personalized Prevention of Cognitive Decline?

OBJECTIVES: to identify the optimal erythrocyte omega-3 index cut-off for predicting cognitive decline and/or polyunsaturated fatty acid (PUFA) treatment response, in order to better define the target population for future dementia prevention trials. DESIGN AND SETTING: Secondary exploratory analysis of the randomized controlled MAPT prevention trial. PARTICIPANTS: 724 dementia-free subjects aged 70 or older with subjective memory complaints, limitations in one instrumental activity of daily living, and/or slow gait speed. INTERVENTION: 800mg docosahexaenoic acid (DHA) and 225mg eicosapentaenoic acid (EPA) daily versus placebo. MEASUREMENTS: Erythrocyte omega-3 index was measured at baseline. Cognition was measured over 3 years with a composite cognitive score (mean of 4 z-scores). RESULTS: Placebo group subjects in the lowest quartile of baseline erythrocyte omega-3 index (i.e. ≤4.83%) underwent significantly more 3-year cognitive decline than the other quartiles (mean composite score difference 0.14, 95%CI [0.00, 0.28], p=0.048). In a ROC curve analysis, the optimal omega-3 index cut-off for predicting notable cognitive decline was 5.3%. There was a consistent but non-significant difference in 3-year cognitive decline of approximately 0.12 points between PUFA-treated and placebo subjects with "low" baseline omega-3 index when the cut-off was set at ≤5.27%. CONCLUSIONS: Dementia-free older adults with an omega-3 index below approximately 5% are at increased risk of cognitive decline, and could be a good target population for testing the cognitive effects of PUFA supplementation.

Trajectory of the MAPT-PACC-Preclinical Alzheimer Cognitive Composite in the Placebo Group of a Randomized Control Trial: Results from the MAPT Study: Lessons for Further Trials.

Defining the primary cognitive endpoint is a major decision for Alzheimer's disease preventive trials. As an example for further trials we present in detail the three-year cognitive decline in the placebo group of MAPT trial, a randomized controlled trial (RCT) using a cognitive composite score (MAPT-PACC). Participants were dementia-free adults 70 years or older, with subjective memory complaints. Our findings as expected showed subjects with older age (>75), higher beta amyloid brain deposition, APOE-ε4 allele carriers, with low RBC DHA+EPA levels and higher CDR level are at higher risk of cognitive decline. The data presented in this paper can be useful for future preventive trials to choose the primary cognitive end point, assess the clinical relevance of cognitive changes and perform sample size calculation for several targeted population eg. ApoE4, amyloid +, oldest old, lower n3-PUFA. We believe that the trial group with CDR 0.5, without being selected by a memory test endpoint is a good target population for AD preventive trials.

Cross-Sectional Associations of Total Plasma Homocysteine with Cortical ß-Amyloid Independently and as a Function of Omega 3 Polyunsaturated Fatty Acid Status in Older Adults at Risk of Dementia.

OBJECTIVES: Elevated total plasma homocysteine is a risk factor for Alzheimer's disease (AD) and there is some evidence that omega-3 polyunsaturated fatty acids (n-3 PUFAs) can modulate the effects of homocysteine-lowering B vitamins on AD related pathologies. Hence we investigated the relationship between total plasma homocysteine and cortical ß-amyloid (Aß) in older adults at risk of dementia. The role of erythrocyte membrane n-3 PUFAs (omega 3 index) on this relationship was also explored. DESIGN: This is a cross-sectional study using data from the Multidomain Alzheimer Preventive Trial (MAPT); a randomised controlled trial. SETTING: French community dwellers aged 70 or over reporting subjective memory complaints, but free from a diagnosis of clinical dementia. PARTICIPANTS: Individuals were from the MAPT trial (n = 177) with data on total plasma homocysteine at baseline and cortical Aß load. MEASUREMENTS: Cortical-to-cerebellar standard uptake value ratios were assessed using [18F] florbetapir positron emission tomography (PET). Total baseline plasma homocysteine was measured using an enzymatic cycling assay. Baseline omega 3 index was measured using gas chromatography. Cross-sectional associations were explored using adjusted multiple linear regression models. RESULTS: We found that total baseline plasma homocysteine was not significantly associated with cortical Aß as demonstrated using multiple linear regression models adjusted for age, sex, education, cognitive status, time interval between baseline and PET-scan, omega-3 index, MAPT group allocation and Apolipoprotein E ε4 status (B-coefficient -0.001, 95 % CI: -0.008,0.006, p = 0.838). Exploratory analysis showed that homocysteine was however significantly associated with cortical Aß in subjects with low baseline omega-3 index (< 4.72 %) after adjustment for Apolipoprotein E ε4 status (B-coefficient 0.041, 95 % CI: 0.017,0.066, p = 0.005, n = 10), but not in subjects with a high baseline omega-3 index (B-coefficient -0.010, 95 % CI: -0.023,0.003, p = 0.132, n = 66). CONCLUSIONS: The role of n-3 PUFAs on the relationship between homocysteine and cerebral Aß warrants further investigation.

Cognitive Changes with Omega-3 Polyunsaturated Fatty Acids in Non-Demented Older Adults with Low Omega-3 Index.

OBJECTIVES: To investigate the changes in specific domains of cognitive function in older adults reporting subjective memory complaints with a low omega-3 index receiving omega 3 polyunsaturated fatty acid (n-3 PUFA) supplementation or placebo. DESIGN: This is a secondary exploratory analysis of the Multidomain Alzheimer Preventive Trial (MAPT) using subjects randomized to the n-3 PUFA supplementation or placebo group. SETTING: French community dwellers aged 70 or over reporting subjective memory complaints, but free from clinical dementia. PARTICIPANTS: A subgroup of MAPT subjects in the lowest quartile of omega-3 index distribution with baseline values ≤ 4.83 % (n = 183). INTERVENTION: The n-3 PUFA supplementation group consumed a daily dose of DHA (800 mg) and EPA (a maximum amount of 225 mg) for 3 years. The placebo group received identical capsules comprising liquid paraffin oil. MEASUREMENTS: Linear mixed-model repeated-measures analyses were used including baseline, 6, 12, 24 and 36-month follow-up data to assess between-group differences in the change in eight cognitive tests over 36 months. RESULTS: There was less decline on the Controlled Oral Word Association Test (COWAT) in the n-3 PUFA supplementation group compared to placebo (p = 0.009; between group mean difference over 36 months, 2.3; 95% CI, 0.6,4.0). No significant differences for any of the other cognitive tests were found, including other tests of executive functioning, although, numerically all results were in favour of the n-3 PUFA supplementation. CONCLUSIONS: We found some evidence that n-3 PUFAs might be beneficial for the maintenance of executive functioning in older adults at risk of dementia with low omega-3 index, but this exploratory finding requires further confirmation. A larger specifically designed randomised controlled trial could be merited.

How to design nutritional intervention trials to slow cognitive decline in apparently healthy populations and apply for efficacy claims: a statement from the International Academy on Nutrition and Aging Task Force.

Interventions are crucial as they offer simple and inexpensive public health solutions that will be useful over the long term use. A Task Force on designing trials of nutritional interventions to slow cognitive decline in older adults was held in Toulouse in September 2012. The aim of the Task Force was to bring together leading experts from academia, the food industry and regulatory agencies to determine the best trial designs that would enable us to reach our goal of maintaining or improving cognitive function in apparently healthy aging people. An associated challenge for this Task Force was to determine the type of trials required by the Public Food Agencies for assessing the impact of nutritional compounds in comparison to well established requirements for drug trials. Although the required quality of the study design, rationale and statistical analysis remains the same, the studies designed to show reduction of cognitive decline require a long duration and the objectives of this task force was to determine best design for these trials. Two specific needs were identified to support trials of nutritional interventions: 1- Risk- reduction strategies are needed to tackle the growing burden of cognitive decline that may lead to dementia, 2- Innovative study designs are needed to improve the quality of these studies.

Representations and practices of prevention in elderly populations: investigating acceptance to participate in and adhesion to an intervention study for the prevention of Alzheimer's disease (ACCEPT study)--the need for a multidisciplinary approach.

BACKGROUND: In the domain of Alzheimer's disease (AD) prevention, various potentially protective factors have been identified in epidemiological studies. Although the results of these observational studies have been relatively consistent, the results of intervention studies remain disappointing. Methodological problems could explain these negative results, like the selection of the population; a plausible assumption is that the older people who agree to take part in these intervention studies differ from those who refuse, and are those that are least likely to benefit from such programs. The aim of this study was (i) to study the determinants of participation in and adhesion to a prevention trial in a population of older individuals via a quantitative approach using a questionnaire, (ii) to study the representations and practices of prevention in this population using a qualitative approach using semi-structured interviews and focus groups. METHOD: The study population for the ACCEPT study was recruited at the time of inclusion of subjects in a prevention trial. The population was made up of persons aged 70 years or older, living at home and demonstrating some form of frailty, defined as a spontaneous memory complaint to their general practitioner or difficulties in carrying out instrumental activities of daily living. We used a quantitative approach based on the administration of a self-completed questionnaire sent to 1680 subjects having accepted to take part in the prevention trial, and to the sample of subjects meeting the inclusion criteria but having refused to take part. The qualitative approach, carried out at the moment of inclusion, involved subjects that having accepted to take part and subjects that having refused. Semi-structured interviews were carried out in order to understand the logic leading to refusal or acceptance. CONCLUSION: The analysis of the results will combine the viewpoints of the different disciplines. It will allow us to better understand the logic at work, to characterise the populations at risk of refusal, and perhaps to remove some of the barriers to participation in prevention programs. The identification of such barriers will provide feedback in terms of the conception and management of prevention measures.

How should we deal with missing data in clinical trials involving Alzheimer's disease patients?

Missing data are frequent in Alzheimer's disease (AD) trials due to the age of participants and the nature of the disease. This can lead to bias and decreased statistical power. We assessed the level and causes of missing data in a 2-year randomised trial of an AD patient management program (PLASA study), and conducted sensitivity analyses on the primary endpoint (functional decline), using various methods for handling missing data: complete case, LOCF, Z-score LOCF, longitudinal mixed effects model, multiple imputation. By 2 years, 32% of the 1131 subjects had dropped out, with the commonest reasons being death (28% of dropouts) and refusal (22%). Baseline cognitive and functional status were predictive of dropout. All sensitivity analyses led to the same conclusion: no effect of the intervention on the rate of functional decline. All analyses demonstrated significant functional decline over time in both groups, but the magnitude of decline and between-group (intervention versus usual care) differences varied across methods. In particular, the LOCF analysis substantially underestimated 2-year decline in both groups compared to other methods. Our results suggest that data were not "missing completely at random", meaning that the complete case method was unsuitable. The LOCF method was also unsuitable since it assumes no decline after dropout. Methods based on the more plausible "missing at random" hypothesis (multiple imputation, longitudinal mixed effects models, z-score LOCF) appeared more appropriate. This work highlights the importance of considering the validity of the underlying hypotheses of methods used for handling missing data in AD trials.

Biomarkers in Alzheimer's disease: not yet surrogate endpoints.

Clinical tests are currently used as endpoints in Alzheimer's disease (AD) trials to measure disease progression based on cognitive, functional, or overall decline. These endpoints are not a perfect reflection of the underlying disease pathology and may be insensitive to disease progression, especially in early AD. Furthermore, they are subject to high variability, leading to large sample sizes and long trial durations. A biomarker that could better reflect AD progression and also predict clinical benefits of drug treatments-a surrogate endpoint-would be of great use. Currently, no surrogate endpoints have been validated in AD. Structural imaging seems to be a better candidate than plasma or CSF biomarkers, but is not yet validated as a surrogate endpoint. More prospective clinical trials are needed for the validation process. While AD biomarkers cannot currently be used as formal surrogate markers, they may nonetheless be useful measures in clinical trials alongside clinical outcomes.

Clinical outcome following lung transplantation in patients with cystic fibrosis colonised with Burkholderia cepacia complex: results from two French centres.

BACKGROUND: Infection with Burkholderia cepacia complex (BCC) is a life threatening complication of cystic fibrosis (CF), often seen as a contraindication for lung transplantation. METHODS: A long term retrospective study was conducted of all patients with CF undergoing lung transplants from January 1990 to October 2006 in two French centres allowing transplantation in patients colonised with BCC. RESULTS: 22 of the 247 lung transplant patients with CF were infected with BCC (B. cenocepacia genomovar III (n = 8), B. multivorans genomovar II (n = 11), B. vietnamiensis genomovar V (n = 2) and B. stabilis genomovar IV (n = 1)). BCC colonisation was not associated with any significant excess mortality (HR 1.5, 95% CI 0.7 to 3.2; p = 0.58). However, early mortality rates tended to be higher in the BCC group than in the non-BCC group (3 month survival: 85% vs 95%, respectively; log rank p = 0.05). Univariate analysis showed that the risk of death was significantly higher for the eight patients infected with B. cenocepacia than for the other 14 colonised patients (HR 3.2, 95% CI 1.1 to 5.9; p = 0.04). None of the other risk factors tested-primary graft failure, late extubation, septicaemia-had a significant effect. The 5 year cumulative incidence rate of bronchiolitis obliterans syndrome was not significantly higher in the BCC group than in the non-BCC group (38% vs 24%, respectively; p = 0.35). CONCLUSION: Our results suggest that BCC infection with a non-genomovar III organism may not be associated with excess mortality after lung transplantation in patients with CF and should not be seen as sufficient reason to exclude lung transplantation. However, colonisation with B. cenocepacia remains potentially detrimental.

Memory complaints to the general practitioner: data from the GuidAge study.

Memory complaints are relatively common in elderly people, although they are not always reported to the general practitioner (GP). These subjective complaints do not necessarily correlate with objective measures of memory impairment or cognitive performance, but they may be an early indication of impairment at a state that is undetectable by standard testing instruments. Memory complaints may also predict future cognitive decline. The GuidAge study is a secondary prevention trial for Alzheimer's disease involving non-demented individuals aged 70 years or older having spontaneously complained of memory problems to their GP. More than half of participants had a Clinical Dementia Rating score of 0.5 at baseline. The percentage of participants reporting problems on the McNair and Kahn scale varied from 6.2% to 78.6% per item. Certain specific memory complaints may be more related than others to the beginning of the neurodegenerative process, and could predict future cognitive decline. The importance of memory complaints should not be underestimated in clinical practice.

Attrition in geriatric research: how important is it and how should it be dealt with?

Attrition, defined as a total loss to follow-up of participants, is a potential major bias in clinical trials. Participants can be lost for many reasons (death, illness, worsened health, refusal, withdrawal, lost to follow up). Attrition may be higher in older populations, so geriatric researchers should pay particular attention to the difficulties it raises. For a proper interpretation of research findings, a detailed analysis of the type of attrition observed and its possible determinants is essential, to determine if attrition has occurred at random or if it is associated to certain patient or treatment characteristics. This paper aims to review different causes of attrition, its prevalence among studies in different elderly populations, and its consequences on research findings. In addition, strategies used to minimise attrition (tracking, bonding, incentives) are discussed, and methods proposed to take this phenomenon into account are proposed.

Increased amikacin dosage requirements in burn patients receiving a once-daily regimen.

Altered pharmacokinetics in burn patients may affect antibiotic plasma concentrations. Typical once-daily dosing (ODD) of 15 mg/kg amikacin (AMK) in burn patients does not always produce peak concentrations (C(max)) reaching the therapeutic objective of six to eight times the minimal inhibitory concentration (MIC). We recorded plasma concentrations following administration of 20 mg/kg AMK in burn patients and studied factors affecting pharmacokinetics. Mean C(max) was 48.3+/-10.8 mg/L and the C(max)/MIC ratio was 6+/-1.35. Statistical analysis demonstrated a relationship between C(max) and the area of the burn and Unit Burn Standard, and between AMK clearance and creatinine clearance (Cl(CR)). We conclude that ODD regimens of AMK in patients with burns >15% body surface area and/or with Cl(CR) >120 mL/min could require doses >20 mg/kg to reach adequate C(max). In all cases, patient therapeutic drug monitoring is essential to ensure the safe usage of these dosing recommendations.

Early blood chemistry in Britain and France.

I review here key research in the early years of the field of blood chemistry. The review includes successes and limitations of animal chemistry in the critical period of the eighteenth and nineteenth centuries. Eighteenth century medical theories emphasized the primacy of body solids. Body fluids were governed by the tenets of humoral pathology. After Boerhaave sparked interest in the chemistry of the body fluids, a new humoralism developed. With the rise of animal chemistry in the eighteenth century, two complementary ideas came into play. The concept of vital force was introduced in 1774, and the chemical composition of animal matters, including the blood, began to be investigated. In the early nineteenth century, the development of new methods of analysis encouraged such chemical studies. Prominent chemists led the field, and physicians also became involved. Physiologists were often opposed to the chemical tradition, but François Magendie recognized the importance of chemistry in physiology. Liebig linked the formation and functions of the blood to general metabolism and so extended the scope of animal chemistry from 1842. About the same time, microscopic studies led to discoveries of the globular structure of the blood, and Magendie's famous pupil, Claude Bernard, began the animal chemistry studies that led him to new discoveries in hematology. This review addresses discoveries, controversies, and errors that relate to the foundations of clinical chemistry and hematology and describes contributions of instrumental investigators.

George Fordyce M.D., F.R.S. (1736-1802): physician-chemist and eccentric.

Educated at Aberdeen and Edinburgh at the height of the 'golden age' of Scottish medicine, George Fordyce came to London, where he began to lecture on chemistry and medical subjects. As a physician at St Thomas's Hospital he became an authority on fevers, but his scientific interests remained wide. He studied the animal fluids involved in digestion, the effects of heat on the body, the applications of chemistry to agriculture and industry, and the gain in weight of metals on calcination, among other problems. His work was highly regarded in his lifetime, but an eccentric lifestyle and a lack of concern for the social graces tended to reduce his standing among medical colleagues. He made no significant discoveries and although his contributions to medical education were important, he has been largely neglected.