A model for malaria treatment evaluation in the presence of multiple species

Plasmodium falciparum and P. vivax are the two most common causes of malaria. While the majority of deaths and severe morbidity are due to P. falciparum, P. vivax poses a greater challenge to eliminating malaria outside of Africa due to its ability to form latent liver stage parasites (hypnozoites), which can cause relapsing episodes within an individual patient. In areas where P. falciparum and P. vivax are co-endemic, individuals can carry parasites of both species simultaneously. These mixed infections complicate dynamics in several ways: treatment of mixed infections will simultaneously affect both species, P. falciparum can mask the detection of P. vivax, and it has been hypothesised that clearing P. falciparum may trigger a relapse of dormant P. vivax. When mixed infections are treated for only blood-stage parasites, patients are at risk of relapse infections due to P. vivax hypnozoites. We present a stochastic mathematical model that captures interactions between P. falciparum and P. vivax, and incorporates both standard schizonticidal treatment (which targets blood-stage parasites) and radical cure treatment (which additionally targets liver-stage parasites). We apply this model via a hypothetical simulation study to assess the implications of different treatment coverages of radical cure for mixed and P. vivax infections and a "unified radical cure" treatment strategy where P. falciparum, P. vivax, and mixed infections all receive radical cure after screening glucose-6-phosphate dehydrogenase (G6PD) normal. In addition, we investigated the impact of mass drug administration (MDA) of blood-stage treatment. We find that a unified radical cure strategy leads to a substantially lower incidence of malaria cases and deaths overall. MDA with schizonticidal treatment was found to decrease P. falciparum with little effect on P. vivax. We perform a univariate sensitivity analysis to highlight important model parameters.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Efficacy of online nutrition professional development for Early Childhood Education Care staff

Background

Early Childhood Education & Care (ECEC) services are a public health setting that influences the lifelong eating habits and health of young Australians. Over 1.3 million children attend ECEC for 30 hours/week. Overweight/obesity, a risk factor for chronic disease, has been associated with this setting. Research reports sub-optimal food provision, poor role modelling and a lack of nutrition training and confidence. Online nutrition education training was provided to ECEC staff, aiming to increase nutrition knowledge/confidence.

Methods

Training was evidence-based, informed by stakeholders and developed by tertiary nutrition experts. ECEC staff were recruited and randomised to intervention or control groups. The intervention group completed an online short course about whole-service approach to healthy eating of 2-3 hours duration. Nutrition knowledge/confidence were measured pre/post-intervention via a pre-validated, online survey. GLM was used to determine differences within and between groups adjusting for years of experience.

Results

Participants (n = 116) were mostly female, aged >36 years, with >10 years industry experience. Post-course, compared to the control group, intervention participants significantly increased confidence to offer 2 serves of grains/day and unsweetened cereals, a variety of vegetables and low-sodium foods, and solid fats were avoided. Confidence to avoid serving discretionary foods did not change and cakes/biscuits were offered frequently.

Conclusions

Following course completion, intervention participants demonstrated increased confidence to serve foods from core food groups, but both groups reported offering discretionary foods frequently. Some results are promising and may improve the nutritional value of food offered at ECEC, but it appears discretionary foods continue to be overprovided. Further research is required to identify the depth of training required to embed important nutrition education concepts in ECEC settings.

Key messages

Evidence-based nutrition education adopting a whole-service approach is effective in increasing ECEC staff nutrition knowledge and confidence to provide foods from core food groups. Further research is required to establish the level of nutrition education appropriate for ECEC staff to avoid the continuing overprovision of discretionary foods to young children.

Barriers and enablers in the implementation of a standardised process for nutrition care: findings from a multinational survey of dietetic professionals in 10 countries

BACKGROUND

To explore the barriers and enablers experienced by nutrition and dietetic professionals in the implementation of the standardised Nutrition Care Process (NCP) across 10 different countries. NCP related beliefs, motivations and values were investigated and compared.

METHODS

A validated online survey was disseminated to nutrition and dietetics professionals in 10 countries in the local language during 2017. Cross-sectional associations and differences between countries were explored for level of implementation, barriers/enablers and attitudes/motivation among the respondents.

RESULTS

Higher NCP implementation was associated with greater occurrence of enabling aspects, as well as fewer occurrences of barriers. The most common enabler was 'recommendation by the national dietetic association' (69%) and the most common barrier was 'lack of time' (39%). A longer experience of NCP use was associated with a more positive attitude towards all NCP aspects. Differences between countries were identified, regarding both the occurrence of barriers/enablers and attitudes/motivations.

CONCLUSIONS

Implementation efforts need to be tailored to country-specific contexts when implementing a new standard of care framework among nutrition and dietetic professionals. Additional research is needed to further assess the management and workplace strategies to support the development of nutrition and dietetics professionals in multidisciplinary healthcare organisations.

Tailored Nutrition Education in the Elderly Can Lead to Sustained Dietary Behaviour Change

OBJECTIVES

Evaluate a 4-week dementia specific nutrition education intervention to determine long term knowledge and healthy dietary behaviour changes in 72 elderly men and women.

DESIGN

A mixed method design used qualitative findings to triangulate quantitative within-subject changes to determine efficacy and sustained dietary behaviour change.

SETTING

Community.

PARTICIPANTS

72 independently-living individuals.

INTERVENTION

4-week dementia specific nutrition education intervention.

MEASUREMENTS

Change in participant attitude, confidence, dietary patterns, cooking behaviour, and knowledge were analysed within-subjects using non-parametric repeated-measures procedures. Significance level was set at 5% (α = 0.05). Effect size (ES) was reported and identified as small (S), medium (M) or large (L) if a significant change was observed.

RESULTS

Compared to before the nutrition education intervention participants had an increase in total knowledge (p < 0.001, ES = 0.972 (L)), consumed a greater variety of vegetables (p = 0.007, ES = 0.35 (M)), used less salt (p = 0.006, ES = -0.42 (M-L)) and increased spice use (p < 0.001, ES = 0.40 (M-L)). Participants overcame barriers to enable sustained change, held a positive view on healthy living and believed government should invest in this sector of the community. Sharing and socialisation emerged as important themes that increased program satisfaction.

CONCLUSION

The dementia specific nutrition program produced a large effect in knowledge improvement from pre to post, which was retained at follow up, consolidated observational and participatory learning which produced a moderate increase in healthy dietary behaviours which participants valued and sustained.

Consumption of a whey protein-enriched diet may prevent hepatic steatosis associated with weight gain in elderly women

BACKGROUND AND AIMS

Protein consumption has been associated with cardio-metabolic benefits, including weight loss and improved insulin sensitivity, and may have potential benefits for individuals with fatty liver disease (FLD). We investigated the effect of increasing dietary protein intake from whey relative to carbohydrate on hepatic steatosis.

METHODS AND RESULTS

A two-year randomized, double-blind, placebo-controlled trial of 30 g/day whey protein-supplemented beverage (protein) or an energy-matched low-protein high-carbohydrate beverage (control) for cardio-metabolic and bone health in 219 healthy elderly women, recruited from the Western Australian general population. Hepatic steatosis was quantified using computed tomographic liver-to-spleen (L/S) ratio. FLD was defined as liver-to-spleen difference <10 Hounsfield units. At baseline, FLD prevalence was 11.4%. Control and protein groups were similar in body mass index (BMI), insulin resistance, L/S ratio and FLD prevalence at baseline. At two-years, dietary protein increased by 20 g in the protein, but not the control, group. Total energy intake and physical activity remained similar between groups. At two-years, BMI and FLD prevalence increased in both groups, with no between group differences. L/S ratio increased in control, but not protein, group at two-years, with no between group differences. In a within group comparison, change in BMI correlated with changes in L/S ratio in control (r = 0.37, P = 0.0007), but not with protein group (r = 0.04, P = 0.73).

CONCLUSION

Increasing dietary protein intake from whey relative to carbohydrate does not reduce weight, hepatic steatosis or the prevalence of FLD in elderly women. However, it may prevent worsening of hepatic steatosis associated with weight gain.

CLINICAL TRIALS REGISTRATION

Australian New Zealand Clinical Trials Registry (Registration no. ACTRN012607000163404).

Dairy product consumption, dietary nutrient and energy density and associations with obesity in Australian adolescents

BACKGROUND

Dairy intake is likely to influence dietary energy density (ED) and nutrient density (ND), which are factors representing aspects of dietary quality. Although evidence suggests dairy intake is unlikely to contribute to obesity, intake tends to decrease over adolescence, potentially as a result of concerns around weight gain. We examined associations between dairy intake, ED and ND, and investigated relationships with obesity in adolescents.

METHODS

The present study comprised a cross-sectional study of 1613 14-year-olds in the Western Australian Pregnancy Cohort (Raine) Study. Adolescents completed a 212-item food frequency questionnaire. Nutrient Rich Food index 9.3 (NRF9.3) was used to estimate ND. Age-specific body mass index (BMI) and waist-height cut-offs were used to categorise obesity risk.

RESULTS

Mean (SD) dairy intake was: 2.62 (1.51) servings daily; ED was 4.53 (0.83) (food and beverage) and 6.28 (1.33) (food only); ND was 373 (109). Dairy intake was inversely associated with ED and positively associated with ND. The odds of being overweight (as assessed by BMI) increased by 1.24 (95% confidence interval = 1.09-1.42) with each 100-point increase in ND, after adjustment for potential confounders and energy intake. ED measures and dairy intake were inversely associated with obesity after adjustment for confounders; associations became nonsignificant after energy adjustment.

CONCLUSIONS

The NRF9.3 was originally designed to assess foods, not diets. Further research in other cohorts to determine whether similar findings exist, or investigations into alternate measures of dietary ND, may prove useful. Our findings may be the result of factors such as an excess consumption of refined but fortified foods. Although higher dairy intakes were associated with higher ND, intakes were not associated with higher obesity risk.

Exercise for depression in care home residents: a randomised controlled trial with cost-effectiveness analysis (OPERA)

BACKGROUND

Many older people living in care homes (long term residential care or nursing homes) are depressed. Exercise is a promising non-drug intervention for preventing and treating depression in this population.

OBJECTIVE

To evaluate the impact of a 'whole-home' intervention, consisting of training for residential and nursing home staff backed up with a twice-weekly, physiotherapist-led exercise class on depressive symptoms in care home residents.

DESIGN

A cluster randomised controlled trial with a cost-effectiveness analysis to compare (1) the prevalence of depression in intervention homes with that in control homes in all residents contributing data 12 months after homes were randomised (cross-sectional analysis); (2) the number of depressive symptoms at 6 months between intervention and control homes in residents who were depressed at pre-randomisation baseline assessment (depressed cohort comparison); and (3) the number of depressive symptoms at 12 months between intervention and control homes in all residents who were present at pre-randomisation baseline assessment (cohort comparison).

SETTING

Seventy-eight care homes in Coventry and Warwickshire and north-east London.

PARTICIPANTS

Care home residents aged ≥ 65 years.

INTERVENTIONS

Control intervention: Depression awareness training programme for care home staff. Active intervention: A 'whole-home' exercise intervention, consisting of training for care home staff backed up with a twice-weekly, physiotherapist-led exercise group.

MAIN OUTCOME MEASURES

Geriatric Depression Scale-15, proxy European Quality of Life-5 Dimensions (EQ-5D), cost-effectiveness from an National Health Service perspective, peripheral fractures and death.

RESULTS

We recruited a total of 1054 participants. Cross-sectional analysis: We obtained 595 Geriatric Depression Scale-15 scores and 724 proxy EQ-5D scores. For the cohort analyses we obtained 765 baseline Geriatric Depression Scale-15 scores and 776 proxy EQ-5D scores. Of the 781 who we assessed prior to randomisation, 765 provided a Geriatric Depression Scale-15 score. Of these 374 (49%) were depressed and constitute our depressed cohort. Resource-use and quality-adjusted life-year data, based on proxy EQ-5D, were available for 798 residents recruited prior to randomisation. We delivered 3191 group exercise sessions with 31,705 person attendances and an average group size of 10 (5.3 study participants and 4.6 non-study participants). On average, our participants attended around half of the possible sessions. No serious adverse events occurred during the group exercise sessions. In the cross-sectional analysis the odds for being depressed were 0.76 [95% confidence interval (CI) 0.53 to 1.09] lower in the intervention group at 12 months. The point estimates for benefit for both the cohort analysis (0.13, 95% CI -0.33 to 0.60) and depressed cohort (0.22, 95% CI -0.52 to 0.95) favoured the control intervention. There was no evidence of differences in fracture rates or mortality (odds ratio 1.07, 95% CI 0.79 to 1.48) between the two groups. There was no evidence of differences in the other outcomes between the two groups. Economic analysis: The additional National Health Service cost of the OPERA intervention was £374 per participant (95% CI -£655 to £1404); the mean difference in quality-adjusted life-year was -0.0014 (95% CI -0.0728 to 0.0699). The active intervention was thus dominated by the control intervention, which was more effective and less costly.

CONCLUSION

The results do not support the use of a whole-home physical activity and moderate-intensity exercise programme to reduce depression in care home residents.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN43769277.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 17, No. 18. See the Health Technology Assessment programme website for further project information.

Under-reporting of energy intake in elderly Australian women is associated with a higher body mass index

OBJECTIVES

Identify the extent of under-reporting of energy intake and the characteristics associated with implausible intakes in elderly women.

DESIGN

Dietary intake was assessed using a 3-day weighed food record. Protein intake was validated by 24-hour urinary nitrogen. To examine under-reporting, participants were grouped according to their energy intake and compared to the Goldberg cut-off equation. Logistic regression was performed to assess the influence of body mass index (BMI) and social-demographic factors on under-reporting.

SETTING

Community dwelling elderly women from Perth, Western Australia.

PARTICIPANTS

217 elderly women aged 70-80 years.

RESULTS

Under-reporters had a higher physical activity level (p<0.001) compared with acceptable-reporters. The under-reporters also had a higher body weight (p=0.006), body mass index (BMI) (p=0.001), waist (p=0.011), hip circumference (p<0.001), whole body fat mass (p<0.001) and percentage body fat (p<0.001) than acceptable-reporters. Under-reporters had a significantly lower intakes of protein, fat, carbohydrate and alcohol (p<0.001) and fewer reported food items, compared with acceptable reporters. However, 24-hour urinary nitrogen was only marginally different between the two groups (p=0.053). Participants with a higher BMI were more likely to under-report their energy intake (BMI=25-29.9: odds ratio=2.98[95% CI=1.46-6.09]; BMI≥30: 5.84[2.41-14.14]).

CONCLUSION

Under-reporting energy intake in elderly women was associated with a higher BMI, body fat and higher self-reported physical activity levels. A higher BMI (≥25) appears to be most significant factor in determining if elderly women will underreport their food intake and may be related to body image. These results have implications for undertaking surveys of food intake in elderly women.

The role of induced pluripotent stem cells in research and therapy of primary immunodeficiencies

The advent of reprogramming technology has greatly advanced the field of stem cell biology and nurtured our hope to create patient specific renewable stem cell sources. While the number of reports of disease specific induced pluripotent stem cells is continuously rising, the field becomes increasingly more aware that induced pluripotent stem cells are not as similar to embryonic stem cells as initially assumed. Our state of the art understanding of human induced pluripotent stem cells, their capacity, their limitations and their promise as it pertains to the study and treatment of primary immunodeficiencies, is the content of this review.

Adequacy and change in nutrient and food intakes with aging in a seven-year cohort study in elderly women

OBJECTIVE

As women age total dietary intake falls which may increase the risk of dietary deficiencies in some individuals. The aims of this study were to investigate the changes in nutrient and dietary intakes that occurred with aging in a seven-year longitudinal study of elderly Australian women and to evaluate the adequacy of their dietary intakes.

DESIGN

Longitudinal population based study on health with ageing.

PARTICIPANTS AND SETTING

911 free-living elderly women aged 70-85 years at baseline from a cohort of 1500 elderly women.

MEASUREMENTS

At baseline, 60 and 84 months, self-reported Food Frequency Questionnaires (FFQ) and demographics were collected and anthropometry measured.

RESULTS

During the 84 month subjects lost height (1.8 cm) and body weight (1.9 kg). Intakes of energy and macronutrients carbohydrate, fat and protein declined significantly over the 84 months. Mean energy derived from saturated fat was above, whereas energy derived from carbohydrate was below, recommended levels of intake at all time points. Intakes of vitamins and minerals all declined with age and subjects had suboptimal intakes of folate, vitamin E and calcium at all time points. The serve sizes for potato and meat and the consumption of milk, bread and variety of vegetables declined significantly over time reflecting changes in nutrient intake.

CONCLUSIONS

Ageing is associated with reduced food intake resulting in inadequate intakes in energy, and some nutrients. Nutrition policy for elderly women should include advice to maintain or increase intakes of carbohydrate, milk, vegetables and fruit whilst continuing to reduce fat intake.

The effects of homocysteine and MTHFR genotype on hip bone loss and fracture risk in elderly women

SUMMARY

Few studies have evaluated the effects of homocysteine and methylenetetrahydrofolate reductase (MTHFR) genotype on age-related bone loss. In our 5-year cohort study with 1,213 women aged 70-85 years, high homocysteine is associated with greater hip bone loss but not fracture risk. The effect of MTHFR genotype on bone density and fracture is weak.

INTRODUCTION

Previous studies on the effects of homocysteine and MTHFR genotype on bone mineral density (BMD) and osteoporotic fracture risk have shown inconsistent results. Few studies have evaluated their effects on age-related bone loss. We evaluated the effects of homocysteine and MTHFR genotype variation on hip BMD and fracture risk over 5 years in a cohort of 1,213 community-dwelling women aged 70-85 years.

METHODS

Nutritional intake and prevalent fracture status were assessed at baseline, plasma homocysteine was measured at year 1, and hip dual-energy X-ray absorptiometry (DXA) BMD was measured at years 1 and 5. Clinical incident osteoporotic fractures confirmed by radiographic report were collected throughout the study and the MTHFR gene C677T and A1298C polymorphisms genotyped. Data were analyzed using analysis of covariance and Cox proportional hazard regression.

RESULTS

The highest tertile of homocysteine was associated with a greater hip BMD loss over 4 years (-2.8%) compared to the middle (-1.6%) and lowest tertiles (-1.2%) (P < 0.001). This effect remained after adjustment for covariates. There was no effect of homocysteine on fracture prevalence or incidence. MTHFR gene variation was only weakly related to one of the bone outcome measures.

CONCLUSION

In this study population, high homocysteine is associated with greater hip bone loss but not fracture risk.

Mental health promotion for the widows of injecting drug users in north-east India

The prevalence of HIV is high in the north-east Indian states of Manipur and Nagaland. The major route of HIV transmission is injecting drug use. Most injecting drug users (IDUs) are male and about 40% are married. The widows of IDUs are among the most disadvantaged people. Many are HIV-infected and experiencing poverty, poor health, social isolation and discrimination, all factors likely to compromise their mental health. Some widows are engaging in HIV risk behaviours, including alcohol and drug misuse, sex work and unprotected sex. There is increasing recognition of the links between poverty and mental health status and risk of HIV infection. People with poor mental health are more likely to engage in HIV risk behaviours.

The effects of high potassium consumption on bone mineral density in a prospective cohort study of elderly postmenopausal women

Few studies have investigated the long-term effects of potassium intake on BMD. In a cohort of 266 elderly women, we found that baseline potassium intake as reflected by 24-hour urine potassium excretion had positive association with BMD measured at 1 and/or 5 years later, suggesting a role of dietary potassium on osteoporosis prevention.

INTRODUCTION

High dietary potassium intake has been suggested to be beneficial for bone structure, but few studies have investigated the long-term effects of potassium intake on BMD in elderly women. We examined the relationship between potassium intake as reflected by 24-hour urine potassium excretion and bone density in a cohort of elderly women.

METHODS

The study subjects were 266 elderly postmenopausal women aged 70-80 years. Twenty-four-hour urinary potassium excretion was determined at baseline. At one year hip DXA BMD was measured, at 5 years hip and total body DXA BMD and distal radius and tibia pQCT vBMD were measured. The effects of potassium were evaluated by ANCOVA according to the quartile of baseline urinary potassium excretion.

RESULTS

After adjustment for confounding factors, subjects in the highest quartile of urinary potassium excretion had significantly higher total hip BMD at 1 (5%) and 5 years (6%), and significantly higher total body BMD (4%) and 4% distal tibia total (7%) and trabecular vBMD (11%) at 5 years than those in the lowest quartile.

CONCLUSIONS

Potassium intake shows positive association with bone density in elderly women, suggesting that increasing consumption of food rich in potassium may play a role in osteoporosis prevention.

Bone structural effects of variation in the TNFRSF1B gene encoding the tumor necrosis factor receptor 2

The 1p36 region of the human genome has been identified as containing a QTL for BMD in multiple studies. We analysed the TNFRSF1B gene from this region, which encodes the TNF receptor 2, in two large population-based cohorts. Our results suggest that variation in TNFRSF1B is associated with BMD.

INTRODUCTION

The TNFRSF1B gene, encoding the TNF receptor 2, is a strong positional and functional candidate gene for impaired bone structure through the role that TNF has in bone cells. The aims of this study were to evaluate the role of variations in the TNFRSF1B gene on bone structure and osteoporotic fracture risk in postmenopausal women.

METHODS

Six SNPs in TNFRSF1B were analysed in a cohort of 1,190 postmenopausal Australian women, three of which were also genotyped in an independent cohort of 811 UK postmenopausal women. Differences in phenotypic means for genotype groups were examined using one-way ANOVA and ANCOVA.

RESULTS

Significant associations were seen for IVS1+5580A>G with BMD and QUS parameters in the Australian population (P = 0.008 - 0.034) and with hip BMD parameters in the UK population (P = 0.005 - 0.029). Significant associations were also observed between IVS1+6528G>A and hip BMD parameters in the UK cohort (P = 0.0002 - 0.003). We then combined the data from the two cohorts and observed significant associations between both IVS1+5580A>G and IVS1+6528G>A and hip BMD parameters (P = 0.002 - 0.033).

CONCLUSIONS

Genetic variation in TNFRSF1B plays a role in the determination of bone structure in Caucasian postmenopausal women, possibly through effects on osteoblast and osteoclast differentiation.

A cohort study of the effect of endogenous estrogen on spine fracture risk and bone structure in elderly women and an assessment of its diagnostic usefulness

The decline in endogenous estrogen concentration after menopause is associated with accelerated bone loss. However, effects in older women remain controversial and the usefulness of estrogen status as a predictor of spine fracture has not been assessed. Therefore, we undertook a prospective cohort study of 1350 women mean age 75 years in order to study the role of endogenous estrogen concentration on the risk of morphometric X-ray absorptiometry (MXA)-defined vertebral deformity and atraumatic clinical spine fracture and the association of endogenous estrogen with bone structure. At 5 years 70 patients (5.2%) had sustained > or = 1 incident spine fracture. The fracture group had significantly lower concentrations of baseline free estradiol index (FEI) median (IQ range) (0.38 (0.22-0.60) vs. 0.49 (0.29-0.84) pmol/nmol, p=0.009). The patients in the lowest tertile of FEI (FEI <0.35) had twice the risk of sustaining a clinical vertebral fracture compared to those subjects in the highest tertile (FEI >0.68) (HR 2.18: 95% CI 1.11-4.28). A low FEI was associated with an increased risk of a vertebral deformity over the 5-year study (OR 1.77: 95% CI 1.02-3.07) for the lowest compared to highest tertile. A low baseline FEI was associated with lower baseline QUS heel bone structure and DXA hip bone structure at 12 months and with deterioration in QUS heel bone structure 5 years later. The effect size of the FEI in predicting spine fracture was similar to the effect size for DXA BMD and heel QUS, probably because of the beneficial effect of the FEI on bone structure. The data suggest that the estrogen effect on reducing spine fracture is at least in part due to an effect on bone structure and its measurement does not significantly improve fracture prediction.

The clinical utility of measured kyphosis as a predictor of the presence of vertebral deformities

Meaured spinal kyphosis, as a predictor of prevalent and incident vertebral deformity, was examined in older women (>70 years) and found to not have sufficient sensitivity or specificity to justify its use as a predictor of present or future vertebral deformity risk.

INTRODUCTION

Kyphosis may be attributable to vertebral deformity and was investigated as a clinical tool for predicting the presence and future risk of vertebral deformity.

METHODS

Kyphosis was measured in 434 women aged 70 years or older and the kyphosis index (KI) calculated. Prevalent and incident vertebral deformities were assessed by morphometric X-ray absorptiometry (MXA). The predictive value of KI was examined.

RESULTS

Severity of kyphosis was categorised by tertile of KI; 65% of anterior thoracic deformities occurred in the 33% of subjects in the highest (most kyphotic) tertile. Using this tertile as a predictor of anterior thoracic deformity, the probability for a positive test rose from 14% for the whole population to 28% and for a negative test the probability fell to 8%. For any spinal deformity the highest tertile of KI increased the probability of a positive test from 34% to 42% and reduced the probability for a negative test to 30%. The incidence of new deformities was 6% over 4 years; a high KI tertile did not increase the probability of any vertebral deformity.

CONCLUSIONS

Severe kyphosis does not increase the probability of detection of a prevalent or incident spinal deformity sufficiently to make it a useful method of selecting patients for further evaluation of spinal deformity.

No associations between OPG gene polymorphisms or serum levels and measures of osteoporosis in elderly Australian women

Bone mass is the single most important risk factor for osteoporotic fractures in the elderly and is mainly influenced by genetic factors accounting for 40-75% of the inter-individual variation. Critical for the bone remodeling process is the balance between the newly discovered members of the tumor necrosis factor ligand and receptor superfamilies, osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand, which mediate the effects of many upstream regulators of bone metabolism. In the present study, we evaluated the impact of sequence variations in the OPG gene on bone mass, bone-related biochemistry including serum OPG and fracture frequency in elderly Australian women. A total of 1101 women were genotyped for 3 different single nucleotide polymorphisms (SNP) within the OPG gene (G1181C, T950C and A163G). The effects of these SNPs and serum OPG on calcaneal quantitative ultrasound measurements, osteodensitometry of the hip and bone-related biochemistry were examined. We found no significant relationship between sequence variations in the OPG gene or serum OPG and bone mass, bone-related biochemistry or fracture frequency. Our findings confirm some recent publications investigating the same SNPs but diverge from others, indicating that generalization of the relationships found in this type of study must be done with caution and signify the importance of determining associations between polymorphisms and osteoporosis in different ethnic groups.

Klotho gene polymorphisms are associated with osteocalcin levels but not bone density of aged postmenopausal women

Osteoporosis is known to have a strong genetic basis. It has been proposed that polymorphisms within the KL (klotho) gene have a significant effect on aging, in particular, the osteoblast defect of aging. The association between polymorphisms within this gene and biochemical markers of bone formation and resorption, bone structure, and fracture rates was studied in 1,190 postmenopausal women with a mean age of 75 years. Genotyping of these polymorphic sites was carried out using Matrix-Assisted Laser Desorption Ionization--Time of Flight (MALDI-ToF) mass spectrometry. The G allele of SNP c.1775G>A was associated with a lower osteocalcin level than the A allele (P = 0.004) in a codominant model. SNPs C-387T and IVS1+8262c>t both showed nonsignificant associations with osteocalcin (P values of 0.063 and 0.068, respectively), but a haplotype analysis of 2 of 5 haplotypes of the three SNPs with a frequency greater than 4% revealed a significant association with osteocalcin (P = 0.036). None of the individual polymorphisms or haplotypes analyzed showed any associations with a marker of bone resorption the deoxypyridinoline creatinine ratio, bone structure, or fracture data. Therefore, the G polymorphism within the c.1775G>A SNP site and a haplotype including this are associated with a reduced osteoblast product osteocalcin. These data suggest that variation in the KL gene product affects osteoblast activity independent of osteoclast activity but that this defect does not result in an effect on bone structure in this population, perhaps because of "rescue" by other genetic or environmental factors in this population.

Association of an aromatase TTTA repeat polymorphism with circulating estrogen, bone structure, and biochemistry in older women

Osteoporosis is a disease that is strongly genetically determined. Aromatase converts androgens to estradiol in postmenopausal women, therefore polymorphisms of the gene for this enzyme may be associated with bone mass and fracture. We investigated the association of the TTTA microsatellite polymorphism in intron 4 of the aromatase (CYP19) gene with bone mineral density (BMD) and fracture in 1,257 women aged 70 yr and greater. The data obtained were stratified based on the presence or absence of a [TTTA]n of 7 (A2), determined from a preliminary analysis of hip dual-energy X-ray absorptiometry BMD, which was present in 27% of the population. The presence of an A2 allele was associated with a higher free estradiol index (0.52 +/- 0.49, P = 0.049) compared with the absence of an A2 allele (0.47 +/- 0.45); higher BMD at all sites of the hip (3.4% total hip, 2.3% femoral neck, 3.6% intertrochanter, 4.1% trochanter) and the lumbar spine (12.7%); higher values for the calcaneal quantitative ultrasound parameters broadband ultrasound (1.3%), speed of sound (0.4%), and stiffness (3.7%); and higher peripheral quantitative computed tomography measures for total (3.4%), trabecular (3.3%), and cortical BMD (3.3%) and the derived stress strain index (SSI) parameters SSI polar (6.4%) and SSI x (6.8%) values. A lower deoxypryridinoline creatinine ratio was observed in subjects with an A2 allele (30.3 +/- 10.4 vs. 27.1 +/- 9.1, P = 0.03). The A2 allele was associated with a lower prevalence of vertebral fracture in subjects who were osteoporotic (odds ratio 0.27, confidence interval 0.09-0.79). Therefore, a common polymorphism of the aromatase gene, perhaps in linkage disequilibrium with a functionally significant CYP19 polymorphism, is associated with bone structure and bone turnover, either by local effects or by effects on circulating bioactive estrogen.

LRP5 gene polymorphisms predict bone mass and incident fractures in elderly Australian women

Postmenopausal osteoporosis and bone mass are influenced by multiple factors including genetic variation. The importance of LDL receptor-related protein 5 (LRP5) for the regulation of bone mass has recently been established, where loss of function mutations is followed by severe osteoporosis and gain of function is related to increased bone mass. The aim of this study was to evaluate the role of polymorphisms in the LRP5 gene in regulating bone mass and influencing prospective fracture frequency in a well-described, large cohort of normal, ambulatory Australian women. A total of 1301 women were genotyped for seven different single nucleotide polymorphisms (SNPs) within the LRP5 gene of which five were potentially informative. The effects of these gene polymorphisms on calcaneal quantitative ultrasound measurements (QUS), osteodensitometry of the hip and bone-related biochemistry was examined. One SNP located in exon 15 was found to be associated with fracture rate and bone mineral density. Homozygosity for the less frequent allele of c.3357 A > G was associated with significant reduction in bone mass at most femoral sites. The subjects with the GG genotype, compared to the AA/AG genotypes showed a significant reduction in BUA and total hip, femoral neck and trochanter BMD (1.5% P = 0.032; 2.7% P = 0.047; 3.6% P = 0.008; 3.1% P = 0.050, respectively). In the 5-year follow-up period, 227 subjects experienced a total of 290 radiologically confirmed fractures. The incident fracture rate was significantly increased in subjects homozygous for the GG polymorphism (RR of fracture = 1.61, 95% CI [1.06-2.45], P = 0.027). After adjusting for total hip BMD, the fracture rate was still increased (RR = 1.67 [1.02-2.78], P = 0.045), indicating factors other than bone mass are of importance for bone strength. In conclusion, genetic variation in LRP5 seems to be of importance for regulation of bone mass and osteoporotic fractures.

Bone mass effects of a BMP4 gene polymorphism in postmenopausal women

The pathogenesis of osteoporosis involves both genetic and environmental factors. On the basis of linkage data suggesting gene effects on bone density at chromosome 14q and data locating the BMP4 gene to 14q, we performed a positional candidate study to examine a possible association of BMP4 gene polymorphisms, hip bone density (n = 1012) and fracture rates (n = 1232) in postmenopausal women (mean age 75). On genotype analysis of the three selected single nucleotide polymorphisms (SNP), the 6007C > T polymorphism was associated with total and intertrochanteric hip BMD and BMD was lower in the 32% of subjects homozygous for the C allele. This polymorphism codes for a nonsynonymous amino acid change with the T allele coding for valine, while the C allele codes for alanine. The difference in BMD was 3.1% (TT vs. CC) and 2.3% (CT versus CC) for the total hip (P = 0.023), and 3.7% (TT vs. CC) and 2.8% (CT versus CC) for the intertrochanter site (P = 0.012). Haplotype analysis demonstrated 6 haplotypes of frequency greater than 2%. A major haplotype defined by G-C-T alleles in SNPs -5826G > A, 3564C > T and 6007C > T respectively, showed association with high bone mass. No SNP showed association with fracture rates. We conclude that a polymorphism found in the BMP4 gene, affecting amino acid sequence, is associated with hip bone density in postmenopausal women, presumably via regulation of anabolic effects on the skeleton.

Effects of endogenous estrogen on renal calcium and phosphate handling in elderly women

High postmenopausal endogenous estrogen concentrations are an important determinant of preservation of bone mass and reduced fracture in elderly women. Calcium supplementation can also reduce bone loss in these patients, suggesting an interaction between estrogen deficiency and calcium balance. Potential mechanisms of estrogen on calcium transport include direct effects on the bone, the kidney, and the bowel. Previous studies have demonstrated effects of estrogen on renal phosphate handling. We have used a cross-sectional, population-based analysis of biochemical data obtained from ambulant elderly women to determine the association of endogenous estradiol with urine calcium and phosphorus excretion. The subjects were 293 postmenopausal women >70 yr old. Factors associated with renal calcium and phosphate excretion were measured, including the filtered calcium and phosphate load, parathyroid hormone (PTH), estradiol, and sex hormone-binding globulin (SHBG). The free estradiol concentration (FE) was calculated from a previously described formula. A high plasma estradiol concentration (r(2) = 0.023, P = 0.01) and a high FE (r(2) = 0.045, P = 0.001) were associated with reduced renal calcium excretion. The estradiol and FE effect on renal calcium excretion remained significant after adjusting for calcium filtered at the glomerulus and serum PTH. A high FE was associated with a reduced renal phosphate threshold in univariate analysis (r(2) = 0.023, P = 0.010). The effect remained significant after adjustment for serum PTH. The size of the effect of the FE was of the same order of magnitude as the effect of PTH on reducing renal calcium excretion and increasing renal phosphate excretion. These data support in vitro and animal data demonstrating an effect of estradiol on renal calcium and phosphate handling and indicate that, in elderly postmenopausal women, the effect is of a similar magnitude to the well-recognized effects of PTH on these physiologically regulated parameters.

Calcium-sensing receptor gene polymorphism A986S does not predict serum calcium level, bone mineral density, calcaneal ultrasound indices, or fracture rate in a large cohort of elderly women

Postmenopausal osteoporosis is a complex and heterogeneous disease influenced by multiple factors and related to peak bone mass achieved in early adult life, followed by a subsequent continuous bone loss. Genetic variance and polymorphisms have been shown to be of clinical significance for osteoporotic fragility fractures. Previous studies have related variations in the calcium sensor receptor (CASR) gene to circulating Ca levels and bone mass in young women and adolescent girls. The aim of this study was to investigate the impact of the A986S polymorphism of the CASR gene on calcium homeostasis and bone metabolism in elderly women. We studied the distribution of the A986S polymorphism in a large cohort of 1252 ambulatory Australian women in relation to biochemical markers of bone metabolism, bone mass evaluated by quantitative ultrasound measurements (QUS) and DXA of the hip, prevalent and 36-month incident fracture data. No effect of the polymorphism was found on circulating calcium level, renal Ca excretion, or biochemical markers of bone turnover. Moreover, A986S was not associated with bone mass or prevalent or incident fractures. Power calculations revealed that a difference in circulating calcium levels of 0.05 mmol/l, a difference in DXA bone density of 24 mg, and a 1.6-fold difference in fracture rate could have been detected with a power of 80%. In conclusion, in a large cohort of elderly women the A986S polymorphism of the CASR gene was not found to be significant for calcium homeostasis or bone mass. It is questioned whether the polymorphism has any clinical significance for postmenopausal osteoporosis.

The T869C TGF beta polymorphism is associated with fracture, bone mineral density, and calcaneal quantitative ultrasound in elderly women

Osteoporosis is a disease that is strongly genetically determined and polymorphisms present in a range of candidate genes may be involved. A number of previous studies have shown an association between the T869C functional polymorphism of the gene for transforming growth factor beta (TGF beta) and bone mineral density (BMD) and fracture, but these studies have been limited to relatively small studies of selected subjects. In a population-based study of 1337 white women over age 70 we examined the TGF beta T869 polymorphism in relation to BMD, calcaneal quantitative ultrasound (QUS), and prevalent and incident fracture. The TGF beta C allele was observed in 50% of the subjects and was associated with reduced hip BMD at all sites (2.8% total hip, 2.4% femoral neck, 2.6% intertrochanter, and 3.4% trochanter) compared to the TGF beta TT genotype. The TGF beta C allele was also associated with a reduction in the QUS parameters BUA, SOS, and stiffness of 0.87%, 0.26%, and 2.4%, respectively, compared to the TGF beta TT genotype. After adjustment for body mass index in an analysis of variance model, the effect of the TGF beta C allele remained significant at the total hip, the femoral neck, and the trochanter, and for the QUS SOS and stiffness parameters. The TGF beta C allele was associated with an increase in osteoporosis [T score < or =-2.5 SD; odds ratio (OR) 2.07; 95% confidence interval (CI) 1.19-3.60] and prevalent fracture (1.37; 95% CI 1.06-1.75). After adjustment for BMD and QUS stiffness, the association of the TGF beta C allele with prevalent fracture was still present (OR 1.40; 95% CI 1.04-1.89), suggesting that the effect of the C allele on fracture was independent of a reduction in BMD and QUS stiffness. Subjects with normal BMD and a TGF beta C allele had an increased risk of incident fracture over 3 years compared to subjects with normal BMD and a TGF beta TT genotype (relative risk 3.95; 95% CI 1.52-10.29). This association was not found in osteopenic or in osteoporotic subjects, indicating a BMD-TGF beta C allele interaction in relation to the association of the TGF beta C allele with fracture risk. These findings are of potential clinical usefulness, as the TGF beta T869C genotype could be used, in conjunction with other genetic and clinical information, to determine an individual's risk of osteoporosis.

Apolipoprotein E4 is associated with reduced calcaneal quantitative ultrasound measurements and bone mineral density in elderly women

Some studies have reported an association between the apolipoprotein E4 (APOE4) allele and reduced bone density and increased propensity to fracture, but this remains controversial as other studies have not found an association between APOE4 and bone density or fracture. No information is available concerning the effect of the APOE4 allele on quantitative ultrasound (QUS) parameters. We therefore examined this issue in a population-based study of 1332 healthy elderly women, examining the effect of the APOE4 allele on QUS parameters at the calcaneus and comparing this to dual-energy X-ray absorptiometry (DEXA) bone mineral density (BMD) at the hip. In addition, we examined the effect of the APOE4 allele on fracture. Subjects who had at least one APOE4 allele (n = 308) had lower calcaneal QUS parameters and lower hip BMD at the total hip, trochanter, and intertrochanter, but not the femoral neck, compared to subjects without an APOE4 allele (n = 1024) after adjustment for age, body mass index (BMI), and smoking. The decrement in QUS parameters and BMD was approximately 2%. Those subjects having an APOE4 allele were also more likely to fall into a low bone density group, defined by a T score of <1 SD below the young normal range (odds ratio [OR] 1.55, 95% confidence interval [CI] 1.08-2.22). We compared both prevalent and incident nontraumatic fractures over 2 years in the APOE4-present group compared with the APOE4-absent group. There were 354 subjects who entered the study with a history of one or more prevalent fractures, and 104 subjects sustained a nontraumatic fracture during the study. These fractures were not associated with the presence of the APOE4 allele, but a 2% decrement in BMD was unlikely to be associated with a statistically observable increase in fractures in this study. The APOE4 allele was not associated with a difference in any biochemical measures of bone formation or resorption, or in estrogen concentration, nor was it associated with a difference in BMI. Therefore, we conclude that the APOE4 allele is associated with a consistent decrease in both QUS parameters at the calcaneus and BMD at the clinically important hip site, and that this is not associated with differences in biochemical measures of bone formation or resorption.

Antigen presentation by macrophages is enhanced by the uptake of necrotic, but not apoptotic, cells

The aim of this study was to determine whether phagocytosis of necrotic or apoptotic cells affects antigen presentation by murine bone marrow-derived macrophages. After uptake of necrotic neutrophils, macrophages were able to stimulate significantly higher T cell proliferation in vitro against both the recall antigen albumin and the mitogen concanavalin A. No such effect was seen following phagocytosis of apoptotic neutrophils. Flow cytometry revealed that, within 4h of ingestion, macrophages that had taken up the necrotic cells expressed higher levels of CD40 than those that had phagocytosed apoptotic cells. Macrophage cultures pulsed with apoptotic, but not necrotic, neutrophils contained higher levels of transforming growth factor beta1, but lower concentrations of tumour necrosis factor alpha, compared to untreated controls. Our interpretation of these results is that macrophages that have taken up necrotic neutrophils co-stimulate T cells with greater efficiency due to rapid CD40 up-regulation, whereas those that have ingested apoptotic cells are not only ineffective in co-stimulation, but also secrete inhibitory cytokine.

Individuals with cystic fibrosis do not display impaired endothelial function or evidence of oxidative damage in endothelial cells exposed to serum

Heightened systemic oxidative stress is increasingly recognized as a feature of cystic fibrosis (CF). The consequences of long-term exposure to free radical attack include a predisposition to diseases such as cancer and atherosclerosis. An increased incidence of malignancy among adult patients with CF has been reported, but the absence of atherosclerotic disease is well described. The aim of the present study was to assess endothelial function in vivo and relate this to the potential of serum from patients with CF to induce oxidative-mediated damage in cultured human endothelial cells. A group of 11 CF patients was matched with a group of healthy volunteers with regard to age and sex. Endothelial function was assessed as endothelium-dependent and -independent vasodilation by measuring forearm blood flow in response to infused acetylcholine and sodium nitroprusside respectively. Confluent monolayers of cultured human endothelial cells were exposed to serum from CF patients and control subjects. Following exposure, cell death was assessed by lactate dehydrogenase release, and the degree of lipid peroxidation in the membrane was assessed by measuring the content of lipid hydroperoxides, malondialdehyde and 4-hydroxynonenal. Endothelial monolayers exposed to serum from CF patients released significantly less lactate dehydrogenase following exposure than those exposed to serum from healthy controls (1.8% and 3.0% respectively; mean difference -1.2%; 95% confidence intervals -1.9% to -0.1%; P<0.05) and contained significantly less 4-hydroxynonenal (0.75 and 3.41 micromol/g of protein respectively; mean difference -2.66 micromol/g; 95% confidence intervals -5.10 to -0.22 micromol/g; P<0.05). There was no significant difference between patients and controls in the extent of serum-induced membrane peroxidation, as assessed by malondialdehyde or lipid hydroperoxides, or in endothelial function, as assessed by forearm blood flow. In conclusion, despite evidence for heightened systemic oxidative stress in CF, patients displayed no impairment of endothelial function, and their serum caused significantly less damage to human endothelial cells than that from matched controls.

Characterization of the antitumor effects of the selective farnesyl protein transferase inhibitor R115777 in vivo and in vitro

R115777 [(B)-6-[amino(4-chlorophenyl)(1-methyl-1H-imidazol-5-yl)-methyl]-4-(3-chlorophenyl)-1-methyl-2(1H)-quinolinone] is a potent and selective inhibitor of farnesyl protein transferase with significant antitumor effects in vivo subsequent to oral administration in mice. In vitro, using isolated human farnesyl protein transferase, R115777 competitively inhibited the farnesylation of lamin B and K-RasB peptide substrates, with IC50s of 0.86 nM and 7.9 nM, respectively. In a panel of 53 human tumor cell lines tested for growth inhibition, approximately 75% were found to be sensitive to R115777. The majority of sensitive cell lines had a wild-type ras gene. Tumor cell lines bearing H-ras or N-ras mutations were among the most sensitive of the cell lines tested, with responses observed at nanomolar concentrations of R115777. Tumor cell lines bearing mutant K-ras genes required higher concentrations for inhibition of cell growth, with 50% of the cell lines resistant to R115777 up to concentrations of 500 nM. Inhibition of H-Ras, N-Ras, and lamin B protein processing was observed at concentrations of R115777 that inhibited cell proliferation. However, inhibition of K-RasB protein-processing could not be detected. Oral administration b.i.d. of R115777 to nude mice bearing s.c. tumors at doses ranging from 6.25-100 mg/kg inhibited the growth of tumors bearing mutant H-ras, mutant K-ras, and wild-type ras genes. Histological evaluations revealed heterogeneity in tumor responses to R115777. In LoVo human colon tumors, treatment with R115777 produced a prominent antiangiogenic response. In CAPAN-2 human pancreatic tumors, an antiproilferative response predominated, whereas in C32 human melanoma, marked induction of apoptosis was observed. The heterogeneity of histological changes associated with antitumor effects suggested that R115777, and possibly farnesyl protein transferase inhibitors as a class, alter processes of transformation related to tumor-host interactions in addition to inhibiting tumor-cell proliferation.

Differential effects of necrotic or apoptotic cell uptake on antigen presentation by macrophages

The induction of pathogenic immune responses may be dependent on the immune system receiving 'danger' signals resulting from tissue damage, rather than tolerogenic stimuli associated with normal cell turnover. The aim was to test this hypothesis by comparing the effects of the uptake of necrotic and apoptotic cells on the ability of antigen-presenting cells (APC) to stimulate immune responses in vitro. The experiments focused on presentation by the macrophage, which is the main cell type adapted for clearing cellular debris in vivo. Murine bone marrow-derived macrophages were pulsed with neutrophils that had been rendered apoptotic or necrotic, and tested for the ability to induce T cell responses. The macrophages that had taken up necrotic, but not apoptotic, cells were able to stimulate recall proliferation by ovalbumin-specific T cells. Furthermore, the response to the mitogen concanavalin A (Con A) was more than 6 times higher when macrophages had been pulsed with necrotic, in comparison with apoptotic, cells. In control experiments, macrophages that had not been exposed to dying neutrophils stimulated weak responses to ovalbumin and Con A. To determine why the uptake of apoptotic and necrotic cells exert opposing effects on the ability of macrophages to stimulate T cells, the expression of costimulatory molecules by treated macrophages, and their production of potentially immunomodulatory cytokines were measured. Flow cytometry revealed that macrophages that had taken up necrotic, but not apoptotic, neutrophils expressed increased levels of CD40 compared to untreated controls within 4 h. Macrophages pulsed with apoptotic cells secreted higher levels of transforming growth factor-beta1 than those ingesting necrotic cells or untreated controls. Our interpretation of these results is that macrophages that have taken up necrotic cell debris present antigens to T lymphocytes with greater efficiency due to transient CD40 upregulation, whereas those that have ingested apoptotic cells are ineffective APC since they secrete inhibitory cytokine.

Oxidative stress during acute respiratory exacerbations in cystic fibrosis

BACKGROUND

Patients with cystic fibrosis experience chronic systemic oxidative stress. This is coupled with chronic inflammation of the lung involving bronchial polymorphonuclear neutrophil accumulation and activation. We hypothesised that, during periods of acute respiratory exacerbation, free radical activity and consequent damage would be most marked and that intensive treatment of the infection would result in improvement towards values found during stable periods.

METHODS

Plasma and red blood cells were collected from 12 healthy normal volunteers and from 12 patients with cystic fibrosis with an acute respiratory exacerbation (increased respiratory symptoms, reduction in forced expiratory volume in one second (FEV1) of more than 10%, and a decision to treat with intravenous antibiotics). Further samples were collected from patients following two weeks of treatment. Samples were analysed for inflammatory markers, markers of free radical damage, and aqueous and lipid phase scavengers.

RESULTS

During respiratory exacerbations FEV1 and forced vital capacity (FVC) were lower than in controls (mean differences -2.82 (95% CI -2.12 to -3.52) and -3. 79 (-3.03 to -4.55) l, respectively) but improved following treatment (mean change 0.29 (95% CI 0.18 to 0.40) and 0.33 (0.23 to 0.43) l, respectively). Inflammatory markers during exacerbations were significantly higher in patients than in controls with the following mean (95% CI) differences: C reactive protein (CRP), 46 (17 to 75) g/l; neutrophil elastase alpha1-antiprotease complexes (NEAPC), 4.4 (1.77 to 7.07) mg/l; white cell count (WCC), 5.3 (4.7 to 5.9) x 10(9)/l. These markers decreased significantly following treatment with the following mean (95% CI) changes: CRP -26 (-10 to -42) g/l; NEAPC -3.1 (-1.3 to -4.9) mg/l; WCC -1.5 (-1.3 to -1.7) x 10(9)/l. Malondialdehyde (MDA) as a marker of free radical activity was significantly higher in patients during exacerbations than in controls with a mean (95% CI) difference of 193 (107 to 279) which improved with treatment (mean change -56 (95% CI -28 to -84) nmol/mmol cholesterol). Red blood cell polyunsaturated fatty acids were significantly lower in patients than in controls with a mean difference of -4.4(95% CI -2.6 to -6.2) moles percent, but did not improve significantly after treatment. Protein carbonyls during exacerbations were not different from controls but did increase with treatment compared with levels during the exacerbation (mean change 0.39 (95% CI 0.11 to 0.67) micromol/g protein). Aqueous and lipid phase scavengers in patients during exacerbations were significantly lower than in controls with the following mean (95% CI) differences: ascorbate, -19.0 (-2.7 to -35.3) micromol/l; sulphydryls, -122 (-77 to -167) micromol/l; retinol, -237 (-47 to -427) nmol/mmol cholesterol; beta-carotene, -52.8 (-11.8 to -93.8) nmol/mmol cholesterol; luteine, -50.4 (-10.4 to -90.4) nmol/mmol cholesterol; lycopene, -90.1 (-30.1 to -150.1) nmol/mmol cholesterol. Treatment resulted in improvement with the following mean (95% CI) changes: sulphydryls, 50 (32 to 68) micromol/l; retinol, 152 (47 to 257) nmol/mmol cholesterol; alpha- and beta-carotene, 0.6 (0.0 to 1.2) and 7.6 (0.0 to 15.2) nmol/mmol cholesterol, respectively; alpha-tocopherol, 839 (283 to 1405) nmol/mmol cholesterol; and lycopene, 8.2 (0.0 to 16.2) nmol/mmol cholesterol.

CONCLUSIONS

Abnormalities of markers of inflammation, free radical activity, and radical scavengers were significantly more extreme during acute respiratory exacerbations and showed improvement with treatment. The need to provide protection from inflammation and free radical damage should therefore be dynamic and related to the inflammatory and oxidative processes.

The management of metformin overdose

Only two cases of deliberate self-poisoning with metformin have been described in the literature. We report the management of three cases, all of which presented with severe lactic acidosis. Two cases had a fatal outcome. The options for treatment and previous cases reported in the literature are reviewed. Recommendations for the management of metformin overdose include early recognition, intensive support of the cardiovascular system, the correction of metabolic acidosis and the maintenance of body temperature. The use of venovenous haemofiltration against a non-lactate containing fluid may improve outcome when sodium bicarbonate alone fails to reverse severe systemic acidosis.