Emergency hospital admissions for the elderly: insights from the Devon Predictive Model

BACKGROUND

In the UK, people aged 85 and over are the fastest growing population group and are predicted to double in number by 2030. Emergency hospital admissions are also rising.

METHODS

All emergency admissions for the registered population in Devon to all English hospitals were analysed by age, and admission rates per thousand registered were calculated. The Devon Predictive Model (DPM) was built, using local data, to predict emergency admissions in the following 12 months. This model was compared with the Combined Predictive Model over five risk categories.

RESULTS

The registered Devon population on 31 March 2011 was 761 652 with 65 892 emergency admissions in 2010/2011. The DPM had 89 variables including several local factors which strengthened the model. Three of the four most powerful predictors were age 85-89, 90-94 and 95 and over. The positive predictive value for the DPM was better than the CPM's in all five risk categories. Half (49.6%) of all emergency admissions were from those aged 65 or over. Admissions rose progressively and significantly in each successive elderly age band. At age 85 and over there were 420 emergency admissions per thousand registered.

CONCLUSIONS

Age, especially 85 and over, has been undervalued as a risk factor for emergency hospital admissions.

The cost of diagnosing Type 2 diabetes mellitus by clinical opportunistic screening in general practice

AIMS

Type 2 diabetes is associated with serious complications and shortens life. Its prevalence is increasing rapidly worldwide and no cure is available. One logical response is to diagnose the condition as early as possible. Clinical opportunistic screening is one mechanism for making the diagnosis before symptoms are reported. This paper reports the cost of using this technique in UK general practice.

METHODS

In one UK general practice, the electronic medical records were searched to determine the number of blood glucose and oral glucose tolerance tests undertaken for non-pregnant adults without known diabetes over three consecutive years. The laboratory, staff and administrative costs associated with these screening tests were calculated. The records of all patients newly diagnosed with Type 2 diabetes during the same period were reviewed to identify diagnoses made by clinical opportunistic screening. Total costs were divided by the number of diagnoses to determine a cost per diagnosis detected by opportunistic screening.

RESULTS

During the study period, 5720 screening tests were conducted for 2763 patients. Over the 3 years, 86 patients were diagnosed with Type 2 diabetes, 54 (63%) via screening (yield 2.0%; number needed to screen 51.2). The screening costs totalled £ 20,372. The average cost per new screen-detected diagnosis was £ 377.

CONCLUSIONS

Almost two-thirds of new cases of Type 2 diabetes can be detected before symptoms are reported, at reasonable cost by opportunistic screening in general practice, without the use of extra resources. As an affordable alternative to population screening, clinical opportunistic screening merits further consideration.

Neuroborreliosis in the South West of England

Although Lyme borreliosis is increasingly diagnosed in the United Kingdom, few systematic studies have been performed there. UK data suggest that the commonest complications are neurological, but inadequate information exists about their nature and the incidence of late neuroborreliosis. Local data are necessary because clinical presentations may show geographical variation. This study aimed to provide data on clinical manifestations in an area of South West England and to estimate treatment delay. We reviewed clinical records of 88 patients in the Royal Devon and Exeter Hospital catchment area who had positive Borrelia antibody tests during a 5-year period. Fifty-six (64%) reported tick bites. The commonest presentations were erythema migrans (65%) and arthralgia/myalgia (27%). However, 22 patients (25%) had neurological symptoms other than headache alone. Fourteen had facial palsy, eight had confusion/drowsiness, four had meningism, five had radiculopathy, two had sixth nerve palsies, and two had peripheral neuropathies. No late, progressive or atypical neurological syndromes were found. Neurological manifestations were generally predictable and usually included either (or all) of meningoencephalitis, facial palsy or radiculopathy.

Home-based cardiac rehabilitation versus hospital-based rehabilitation: A cost effectiveness analysis

BACKGROUND

Home-based cardiac rehabilitation offers an alternative to traditional, hospital-based cardiac rehabilitation.

AIM

To compare the cost effectiveness of home-based cardiac rehabilitation and hospital-based cardiac rehabilitation.

METHODS

104 patients with an uncomplicated acute myocardial infarction and without major comorbidity were randomized to receive home-based rehabilitation (n=60) i.e. nurse facilitated, self-help package of 6 weeks' duration (the Heart Manual) or hospital-based rehabilitation for 8-10 weeks (n=44). Complete economic data were available in 80 patients (48 who received home-based rehabilitation and 32 who received hospital-based rehabilitation). Healthcare costs, patient costs, and quality of life (EQ-5D4.13) were assessed over the 9 months of the study.

RESULTS

The cost of running the home-based rehabilitation programme was slightly lower than that of the hospital-based programme (mean (95% confidence interval) difference - 30 pounds sterling (- 45 pounds sterling to - 12 pounds sterling) [-44 euro, -67 euro to -18 euro] per patient. The cost difference was largely the result of reduced personnel costs. Over the 9 months of the study, no significant difference was seen between the two groups in overall healthcare costs (78 pounds sterling, - 1102 pounds sterling to 1191 pounds sterling [-115 euro, -1631 euro to -1763 euro] per patient) or quality adjusted life-years (-0.06 (-0.15 to 0.02)). The lack of significant difference between home-based rehabilitation and hospital-based rehabilitation did not alter when different costs and different methods of analysis were used.

CONCLUSIONS

The health gain and total healthcare costs of the present hospital-based and home-based cardiac rehabilitation programmes for patients after myocardial infarction appear to be similar. These initial results require affirmation by further economic evaluations of cardiac rehabilitation in different settings.

Development of an educational 'toolkit' for health professionals and their patients with prediabetes: the WAKEUP study (Ways of Addressing Knowledge Education and Understanding in Pre-diabetes)

AIMS

To identify key messages about pre-diabetes and to design, develop and pilot an educational toolkit to address the information needs of patients and health professionals.

METHODS

Mixed qualitative methodology within an action research framework. Focus group interviews with patients and health professionals and discussion with an expert reference group aimed to identify the important messages and produce a draft toolkit. Two action research cycles were then conducted in two general practices, during which the draft toolkit was used and video-taped consultations and follow-up patient interviews provided further data. Framework analysis techniques were used to examine the data and to elicit action points for improving the toolkit.

RESULTS

The key messages about pre-diabetes concerned the seriousness of the condition, the preventability of progression to diabetes, and the need for lifestyle change. As well as feedback on the acceptability and use of the toolkit, four main themes were identified in the data: knowledge and education needs (of both patients and health professionals); communicating knowledge and motivating change; redesign of practice systems to support pre-diabetes management and the role of the health professional. The toolkit we developed was found to be an acceptable and useful resource for both patients and health practitioners.

CONCLUSIONS

Three key messages about pre-diabetes were identified. A toolkit of information materials for patients with pre-diabetes and the health professionals and ideas for improving practice systems for managing pre-diabetes were developed and successfully piloted. Further work is needed to establish the best mode of delivery of the WAKEUP toolkit.

Attitudes of GPs to the diagnosis and management of impaired glucose tolerance: the practitioners' attitudes to hyperglycaemia (PAtH) questionnaire

AIMS

To develop and pilot a survey instrument assessing general practitioners' (GP) attitudes to the diagnosis and management of one form of pre-diabetes, impaired glucose tolerance (IGT) and to assess the performance of the questionnaire.

METHODS

Qualitative data together with an audit were used to generate questionnaire items, which were then subjected to a process of pre-piloting and piloting to generate a finalised item list. The pilot questionnaire was sent to 222 principal GPs in three PCTs in South West England. The first fifty responders were asked to complete the questionnaire again 2 weeks later. Principal components analysis with a Varimax rotation was used to detect latent factors within the data that may help to explain the attitudes of GPs.

RESULTS

The response rate after one reminder was 54.1%. Four robust factors were identified which were internally consistent (range of Cronbach's alpha=0.79-0.65), homogeneous (item-total correlations=0.60-0.21), and stable (test-retest correlation=0.74-0.58) accounting for 31.1% of the variance. The predictive validity of the item list was assessed (P=0.02 for factor 1).

CONCLUSIONS

The PAtH questionnaire identifies four factors that help to describe GPs attitudes to the diagnosis and management of IGT.

Home-based versus hospital-based rehabilitation after myocardial infarction: A randomized trial with preference arms--Cornwall Heart Attack Rehabilitation Management Study (CHARMS)

BACKGROUND

Participation in cardiac rehabilitation after acute myocardial infarction is sub-optimal. Offering home-based rehabilitation may improve uptake. We report the first randomized study of cardiac rehabilitation to include patient preference.

AIM

To compare the clinical effectiveness of a home-based rehabilitation with hospital-based rehabilitation after myocardial infarction and to determine whether patient choice affects clinical outcomes.

DESIGN

Pragmatic randomized controlled trial with patient preference arms.

SETTING

Rural South West England.

METHODS

Patients admitted with uncomplicated myocardial infarction were offered hospital-based rehabilitation classes over 8-10 weeks or a self-help package of six weeks' duration (the Heart Manual) supported by a nurse. Primary outcomes at 9 months were mean depression and anxiety scores on the Hospital Anxiety Depression scale, quality of life after myocardial infarction (MacNew) score and serum total cholesterol.

RESULTS

Of the 230 patients who agreed to participate, 104 (45%) consented to randomization and 126 (55%) chose their rehabilitation programme. Nine month follow-up data were available for 84/104 (81%) randomized and 100/126 (79%) preference patients. At follow-up no difference was seen in the change in mean depression scores between the randomized home and hospital-based groups (mean difference: 0; 95% confidence interval, -1.12 to 1.12) nor mean anxiety score (-0.07; -1.42 to 1.28), mean global MacNew score (0.14; -0.35 to 0.62) and mean total cholesterol levels (-0.18; -0.62 to 0.27). Neither were there any significant differences in outcomes between the preference groups.

CONCLUSIONS

Home-based cardiac rehabilitation with the Heart Manual was as effective as hospital-based rehabilitation for patients after myocardial infarction. Choosing a rehabilitation programme did not significantly affect clinical outcomes.

Prevalence and clinical implications of the inter-arm blood pressure difference: a systematic review

A blood pressure (BP) difference between arms was first reported over 100 years ago. Knowledge of its prevalence and relevance to the accurate measurement of BP remains poor. Current hypertension guidelines do not emphasise it. The objectives of this study were to establish the best estimate of prevalence of the inter-arm difference (IAD) in the population, to consider its implications for accurate BP measurement and treatment, and to discuss its aetiology and potential as a risk marker for cardiovascular disease. Systematic literature review was carried out. The data sources were Medline EMBASE and CINAHL databases, and Index of Theses. Studies reporting prevalence rates of IAD were retrieved and considered for inclusion against explicit methodological criteria. Point prevalence rates were extracted and weighted mean prevalence rates calculated. The main outcome measures were weighted mean prevalences of systolic IAD > or =10 and > or =20 mm Hg and of diastolic IAD > or =10 mm Hg. Thirty-one studies were identified. Most had methodological weaknesses; only four met the inclusion criteria. Pooled prevalences of the IAD from these four studies were 19.6% systolic > or =10 mm Hg (95% CI 18.0-21.3%), 4.2% systolic > or =20 mm Hg (95% CI 3.4-5.1%) and 8.1% diastolic > or =10 mm Hg (95%CI 6.9-9.2%). In conclusion, an IAD is present in a substantial number of patients and should be looked for whenever diagnosis and treatment depend on accurate measurements of BP. The importance of an IAD should be better emphasised in current hypertension management guidelines. There is evidence associating an IAD with peripheral vascular disease, raising the possibility that its presence may predict cardiovascular events.

A simple pragmatic system for detecting new cases of type 2 diabetes and impaired fasting glycaemia in primary care

BACKGROUND

Although whole population screening for type 2 diabetes is not currently considered to be justified, targeted screening within higher risk groups may be more cost-effective, and more pragmatic.

OBJECTIVES

Our aim was to investigate the feasibility and performance of a pragmatic system for identifying patients with type 2 diabetes and impaired fasting glycaemia (IFG).

METHODS

A clustered observational survey of the prevalence of diabetes and IFG was carried out in randomly selected patients from four at-risk groups. Patients were identified by computerized searching of practice databases for age and body mass index (BMI) risk criteria. Sixteen practices in South West England screened 1287 Caucasian patients from four groups with progressive levels of theoretical risk (age >70 and BMI >or=33, age >65 and BMI >or=31, age >60 and BMI >or=29, and age >50 and BMI >or=27). Fasting plasma glucose was measured and repeated if abnormal to determine the prevalence of new cases in each group. BMI and age data were validated against measures taken at the clinic.

RESULTS

The response rate was 60.6% and the prevalence of new cases of type 2 diabetes in each group was 4.7% [95% confidence interval (CI) 2.8-7.7], 5.7% (95% CI 4.0-8.2), 3.8% (95% CI 2.4-6.0) and 2.6% (95%CI 1.4-4.7), respectively. An additional 5.2-8.4% had IFG.

CONCLUSIONS

Targeted screening by searching existing GP records for age and BMI criteria is feasible for use in general practice in the UK. Screening of patients with a BMI of >or=27 and aged >50 by fasting glucose identified a substantial prevalence of undetected type 2 diabetes and IFG. The relative costs and benefits as well as the pragmatic advantages of different systems need further evaluation.

A case of lead poisoning due to snooker chalk

A 3 year, 9 month old child with pica presented with a blood lead concentration of 1.74 micromol/l (360 microg/l). The source of poisoning was snooker chalk (lead content 7200 microg/g). She was treated with intravenous calcium disodium edetate chelation. Thirty months later her blood lead was 0.39 micromol/l (80 microg/l). This case illustrates the need to be vigilant for more unusual causes of lead poisoning in the home.

Correlation between plasma total homocysteine and copper in patients with peripheral vascular disease

BACKGROUND

Increased concentrations of both plasma total homocysteine and copper are separately associated with cardiovascular disease. Correlations between plasma total homocysteine, trace elements, and vitamins in patients with peripheral vascular disease have not been investigated.

METHODS

The concentrations of trace elements in plasma were determined by the multielement analytical technique of total-reflection x-ray fluorescence spectrometry. Plasma total homocysteine was determined by HPLC.

RESULTS

In the univariate and multivariate regression analyses, copper was positively correlated with plasma total homocysteine in all subjects (coefficient +/- SE, 0.347 +/- 0.113; P = 0.0026 and coefficient +/- SE, 0.422 +/- 0.108; P = 0.0002, respectively), and in patients with peripheral vascular disease (coefficient +/- SE, 0.370 +/- 0.150; P = 0.016; and coefficient +/- SE, 0.490 +/- 0.151; P = 0.0025, respectively). Correlation between copper and plasma total homocysteine was not detected in healthy control subjects. The concentration of calcium in plasma (67.5 vs 80. 8 microg/g) was significantly lower in the patients than in the control subjects (P = 0.02). When the patients were divided into groups, the patients with suprainguinal lesions had significantly higher copper concentrations (P = 0.04) and significantly lower selenium and calcium concentrations (P = 0.01 and 0.008, respectively) than the healthy subjects. Patients had higher concentrations of autoantibodies against oxidized LDL and concentrations of thiobarbituric acid-reactive substance than the healthy subjects (P <0.0001 and P = 0.001, respectively). The concentrations of plasma total homocysteine and alpha-tocopherol were significantly higher, and the concentrations of vitamin B(6) and beta-carotene were lower in the patients than the healthy subjects.

CONCLUSION

Our findings suggest that the atherogenicity of homocysteine may be related to copper-dependent interactions.

Radiation induced sarcoma of the head and neck

BACKGROUND

Radiation-induced sarcoma of the head and neck (RISHN) is a long-term complication of treatment. The rarity of this tumour is reflected in the very few series reported in the English language medical literature. The incidence of RISHN is, however, likely to increase due to progressive aging of the population combined with improved survival in head and neck cancer patients resulting from better treatment regimes. Diagnosis and management of this problem can be extremely challenging and the overall outlook has been reported to be very bleak. As survival data from isolated case reports cannot be expected to provide reliable information on outcome, we have reviewed 69 cases reported in the English medical literature since 1966 and pooled this information with our experience in treatment of RISHN.

PATIENTS AND METHODS

Ten patients with features of a RISHN were treated at the Royal Marsden Hospital between 1944 and 1997. The features of RISHN, treatment, and outcome were analysed in these patients. Additionally, 61 eligible patients with RISHN reported in the literature between 1966 and 1997 were pooled with nine of our patients to form the RISHN group (n = 70). This group was then compared for survival with 124 patients with a diagnosis of head and neck sarcoma registered on the Head and Neck Sarcoma database at the Royal Marsden Hospital (SHN group). Lifetables were constructed using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

There was no site of predilection for RISHN, but malignant fibrous histiocytoma (MFH) was the commonest pathological diagnosis. The period of latency between initial radiation therapy and diagnosis of RISHN ranged from 9 to 45 years with a median of 17 years. Surgery was the mainstay of treatment and follow-up ranged from 6 months to 15 years with a median of 48 months. The actuarial five-year disease free survival in these patients was 60%.

CONCLUSION

There is at present little or no prospect for effective prevention of RISHN and therefore, a high index of suspicion based on the patient's symptoms assumes great importance in the outcome of these patients. Although surgical management of RISHN is challenging because of the close proximity of the tumour to important regional structures and the technical difficulties of operating in an irradiated area, complete surgical excision appears to offer the best means for palliation and the only realistic chance for long-term survival.

Radiation induced sarcoma of the head and neck

BACKGROUND

Radiation-induced sarcoma of the head and neck (RISHN) is a long-term complication of treatment. The rarity of this tumour is reflected in the very few series reported in the English language medical literature. The incidence of RISHN is, however, likely to increase due to progressive aging of the population combined with improved survival in head and neck cancer patients resulting from better treatment regimes. Diagnosis and management of this problem can be extremely challenging and the overall outlook has been reported to be very bleak. As survival data from isolated case reports cannot be expected to provide reliable information on outcome, we have reviewed 69 cases reported in the English medical literature since 1966 and pooled this information with our experience in treatment of RISHN.

PATIENTS AND METHODS

Ten patients with features of a RISHN were treated at the Royal Marsden Hospital between 1944 and 1997. The features of RISHN, treatment, and outcome were analysed in these patients. Additionally, 61 eligible patients with RISHN reported in the literature between 1966 and 1997 were pooled with nine of our patients to form the RISHN group (n = 70). This group was then compared for survival with 124 patients with a diagnosis of head and neck sarcoma registered on the Head and Neck Sarcoma database at the Royal Marsden Hospital (SHN group). Lifetables were constructed using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

There was no site of predilection for RISHN, but malignant fibrous histiocytoma (MFH) was the commonest pathological diagnosis. The period of latency between initial radiation therapy and diagnosis of RISHN ranged from 9 to 45 years with a median of 17 years. Surgery was the mainstay of treatment and follow-up ranged from 6 months to 15 years with a median of 48 months. The actuarial five-year disease free survival in these patients was 60%.

CONCLUSION

There is at present little or no prospect for effective prevention of RISHN and therefore, a high index of suspicion based on the patient's symptoms assumes great importance in the outcome of these patients. Although surgical management of RISHN is challenging because of the close proximity of the tumour to important regional structures and the technical difficulties of operating in an irradiated area, complete surgical excision appears to offer the best means for palliation and the only realistic chance for long-term survival.

A cytochrome P450 terpenoid hydroxylase linked to the suppression of insect juvenile hormone synthesis

A cDNA encoding a cytochrome P450 enzyme was isolated from a cDNA library of the corpora allata (CA) from reproductively active Diploptera punctata cockroaches. This P450 from the endocrine glands that produce the insect juvenile hormone (JH) is most closely related to P450 proteins of family 4 and was named CYP4C7. The CYP4C7 gene is expressed selectively in the CA; its message could not be detected in the fat body, corpora cardiaca, or brain, but trace levels of expression were found in the midgut and caeca. The levels of CYP4C7 mRNA in the CA, measured by ribonuclease protection assays, were linked to the activity cycle of the glands. In adult females, CYP4C7 expression increased immediately after the peak of JH synthesis, reaching a maximum on day 7, just before oviposition. mRNA levels then declined after oviposition and during pregnancy. The CYP4C7 protein was produced in Escherichia coli as a C-terminal His-tagged recombinant protein. In a reconstituted system with insect NADPH cytochrome P450 reductase, cytochrome b5, and NADPH, the purified CYP4C7 metabolized (2E,6E)-farnesol to a more polar product that was identified by GC-MS and by NMR as (10E)-12-hydroxyfarnesol. CYP4C7 converted JH III to 12-trans-hydroxy JH III and metabolized other JH-like sesquiterpenoids as well. This omega-hydroxylation of sesquiterpenoids appears to be a metabolic pathway in the corpora allata that may play a role in the suppression of JH biosynthesis at the end of the gonotrophic cycle.

Cellular mechanisms of reactive oxygen metabolite generation from human polymorphonuclear leukocytes induced by crocidolite asbestos

In our previous study, we demonstrated that reactive oxygen metabolites (ROM) generation from phagocytic cells may be involved in the carcinogenic mechanism of crocidolite asbestos. In the present study, the mechanism of human polymorphonuclear leukocytes (PMN) to generate ROM by crocidolite was investigated using verapamil, a calcium channel inhibitor; staurosporine, a NADPH oxidase inhibitor; and cytochalasin B (CB), an inhibitor of phagocytosis. The results indicate that whereas verapamil and staurosporine inhibited the crocidolite-induced ROM generation from PMN dose-dependently, CB caused an enhancement. We conclude that crocidolite-induced ROM generation involves a cell surface reaction due to influx of extracellular calcium through calcium channels and the activation of NADPH oxidase on the PMN cell membrane. This hypothesis was indirectly supported by dose-dependent enhancement of the ROM generation by CB, as CB increases calcium ion permeability in PMN. However, as in our previous studies, the time course of the ROM generation and the cell type difference suggested that ROM were also generated intracellularly from PMN due to phagocytosis of crocidolite. In conclusion, our evidence indicates that ROM generation from PMN by crocidolite involves cellular mechanisms related both to direct cell surface membrane interactions, together with an apparent phagocytic-dependent process.

Substrate specificity for the epoxidation of terpenoids and active site topology of house fly cytochrome P450 6A1

Heterologous expression in Escherichia coli, purification, and reconstitution of house fly P450 6A1 and NADPH-cytochrome P450 reductase were used to study the metabolism of terpenoids. In addition to the epoxidation of cyclodiene insecticides demonstrated previously [Andersen et al. (1994) Biochemistry 33, 2171-2177], this cytochrome P450 was shown to epoxidize a variety of terpenoids such as farnesyl, geranyl, and neryl methyl esters, juvenile hormones I and III, and farnesal but not farnesol or farnesoic acid. P450 6A1 reconstituted with NADPH-cytochrome P450 reductase and phosphatidylcholine did not metabolize alpha-pinene, limonene, of the insect growth regulators hydroprene and methoprene. The four geometric isomers of methyl farnesoate were metabolized predominantly to the 10,11-epoxides, but also the 6,7-epoxides and to the diepoxides. The 10,11-epoxide of methyl (2E,6E)-farnesoate was produced in a 3:1 ratio of the (10S) and (10R) enantiomers. Monoepoxides of methyl farnesoate were metabolized efficiently to the diepoxides. Methyl farnesoate epoxidation was strongly inhibited by a bulky substituted imidazole. The active site topology of P450 6A1 was studied by the reaction of the enzyme with phenyldiazene to form a phenyl-iron complex. Ferricyanide-induced in situ migration of the phenyl group showed formation of the N-phenylprotopor-phyrinporphyrin IX adducts in a 17:25:33:24 ratio of the NB:NA:NC:ND isomers. These experiments suggest that metabolism of xenobiotics by this P450, constitutively overexpressed in insecticide-resistant strains of the house fly, is not severely limited by stereochemically constrained access to the active site.

Surface chemistry and biological pathogenicity of silicates: an X-ray photoelectron spectroscopic study

We extend our electron spectroscopy for chemical analysis studies of the chemistry of silicates to provide direct surface chemical information on the interactions involved in silicate-induced lung and tissue pathology. A total of five fibrous and non-fibrous silicate minerals, primarily amphiboles, have been studied: anthophyllite, tremolite, cummingtonite, hornblende and actinolite. We have followed the 'inlattice' surface chemistry of these materials and monitored features such as the simultaneous presence of four- and six-coordinate (with respect to oxygen) structural aluminium, and the presence of iron in the M4 octahedral positions. In vitro experiments involving contact of the silicate with cultured murine Ehrlich cells have identified modifications in the surface chemistry of Al, Mg and Fe in the silicates and changes in cellular iron content.

Commentary: Caution needed in introducing warfarin treatment

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Biochemical indices and neuromuscular function tests in rural Gambian schoolchildren given a riboflavin, or multivitamin plus iron, supplement

Ninety preselected children, aged between 8 and 14 years, living in two rural West African (Gambian) villages, were randomly divided into three groups, matched for age and sex. One group received a placebo (lactose) tablet, one received riboflavin (5 mg) on 5 d every week, which was sufficient to correct an endemic riboflavin deficiency, and one received a multivitamin supplement (Protovit; Hoffmann La Roche), on 5 d every week, together with FeSO4 (200 mg) once weekly, and the supplements were given for 1 year. Neuromuscular tests, including arm tremor and manipulative skills, were performed on three occasions: once just before the introduction of the supplements; again 6 weeks after commencing the supplements; and again 1 year later. Venous blood samples were collected at the same time as the first two sets of neuromuscular tests. These samples were used for haematology and nutrient status indices: plasma ferritin, ascorbic acid, cyanocobalamin and pyridoxal phosphate, and erythrocyte tests for folate status, for riboflavin status (erythrocyte glutathione reductase activation coefficient) and thiamine status (erythrocyte transketolase activation coefficient). The riboflavin in both supplements achieved a clear-cut response in biochemical status, which was dose-dependent. The pyridoxine, ascorbic acid and Fe components of the multivitamin also affected the associated biochemical indices. Although overall the arm tremor and related neuromuscular function tests did not respond significantly to the supplements, significant improvement was seen in the boys for the arm-tremor test in both the supplemented groups.

Crocidolite-induced reactive oxygen metabolites generation from human polymorphonuclear leukocytes

In order to study the mechanism of carcinogenicity of crocidolite asbestos, we have investigated the species of reactive oxygen metabolites (ROM) induced by crocidolite from human polymorphonuclear leukocytes (PMN) utilizing both an electron spin resonance (ESR) spin trapping method with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and a luminol-dependent chemiluminescence (CL) method. The present study confirms the generation of OH. from human peripheral blood PMN stimulated by UICC crocidolite utilizing ESR. In addition, PMN incubated with 25-400 micrograms/ml of crocidolite produced CL, the intensity of CL increasing in a dose-dependent manner. Superoxide dismutase, catalase, and dimethyl sulfoxide, which are scavengers of O2-, H2O2, and OH., respectively, inhibited the production of crocidolite-stimulated CL from PMN, also in a dose-dependent manner. Sodium azide, an inhibitor of myeloperoxidase (MPO) to produce OCl-, also inhibited CL production. These results suggest the involvement of O2-, H2O2, OH., and OCl- in the production of CL by crocidolite-stimulated PMN. In conclusion, it is proposed that OH. is a key ROM species in the mechanism of crocidolite-induced carcinogenesis.

Free radicals in brain metabolism and pathology

Reactive oxygen metabolites (ROM), namely superoxide and hydroxyl free radicals and hydrogen peroxide, are produced as a consequence of the physiological metabolic reactions and functioning of the central nervous system. ROM have also been implicated in the aetiopathogenic processes of a number of pathological conditions of the brain. While primarily indirect, evidence for this view is accumulating, and credence for the participation of free radical oxidative interactions in promoting tissue injury in such conditions as brain trauma, ischaemia, and toxicity, and in neurodegenerative diseases such as Parkinson's disease, Alzheimer's dementia, multiple sclerosis, and lipofuscinosis, is growing. Concomitant with this new understanding of the injurious role of free radical oxidants in neural pathology, is the increasing appreciation for the need for both fundamental and clinical research into the development of the potential preventative and therapeutic benefits that are now being foreseen for a variety of antioxidant nutritional and pharmacological interventions.

A trial of zinc supplementation in young rural Gambian children

The present study tested the hypothesis that inadequate Zn intake might be responsible for failure to thrive and impaired catch-up growth in young rural Gambian children, and that Zn supplements might be beneficial. Gambian children might be deprived of Zn because of its poor availability from their predominantly plant-based diet. Rural Gambian children (110; fifty boys, sixty girls) aged between 0.57 and 2.30 years were divided into two matched groups, one to receive 70 mg Zn twice weekly for 1.25 years, and the other a placebo. Growth and mid-upper-arm circumference were measured at weekly intervals throughout the study and illnesses were monitored. Capillary blood and urine samples were collected at 0, 2 and 8 weeks. Body weights and arm circumferences showed a linear increase, plus a seasonal effect (rainy season faltering). For body weight there was no significant overall effect of the supplement. For arm circumference, a very small (2%) but significant (P < 0.01) difference favoured the supplemented group. Plasma thymulin was much lower at the first clinic than at the second and third clinics, and in vitro Zn stimulation was greater at the first clinic. There was, however, no effect of Zn in vivo. Likewise, Zn did not significantly benefit T-cell numbers or ratios, secretory IgA in urine, circulating hormone levels or biochemical indices of Zn status. One index of intestinal permeability, i.e. lactulose: creatinine, was improved (P < 0.02) by the supplement, but the lactulose: mannitol value was not; this requires further investigation. Dietary Zn deficiency is, thus, unlikely to be of major overall importance for rural Gambian children's ability to thrive, and blanket Zn supplementation is not justified. There may, however, be vulnerable sub-groups who would benefit from Zn supplements.

A study of whole-body isotope dilution of [14C]ascorbic acid in guinea-pigs with graded ascorbate intakes

The purpose of the present study was first to assess the extent to which unlabelled ascorbate in the diet of guinea-pigs can exchange with labelled ascorbate within their organs when the dietary intake is varied over a wide range, and second to determine whether the retention of label might be used to assess either the amount of ascorbate intake or its biological availability where these are not known. The retention of [14C]ascorbate in the body and in various organs of guinea-pigs were, therefore, measured following a 13 d period of graded dietary intakes of ascorbate. It was found first, that the amount of label retained in each of the organs, 13 d after the initial dose of labelled ascorbate, was much more closely related to the amount of ascorbate intake after labelling than to the intake (and tissue ascorbate levels) before and at the time of labelling. Second, most of the individual internal organs exhibited a constant relationship between the specific activity at 13 d and the dietary intake, except for brain which was flushed to a smaller extent. Third, in agreement with several previous studies a high proportion of the radioactive label in the tissues was found to be still present in ascorbate. The specific activity of column-purified ascorbate was very similar to the estimated specific activity in the crude extract, which implies that it may be possible to estimate specific activities (or stable isotope enrichments) at certain sites without rigorous isolation procedures. Fourth, the amount of radioactivity appearing in the urine 2 d before killing the animals was correlated with the amount of ascorbate intake and with tissue specific activities, suggesting that intakes (or bioavailability) might be predicted from the patterns of label-appearance in the urine.

Incorporation of [3H]proline into collagen and other proteins in rats fed diets with various zinc concentrations

Incorporation of labeled proline into liver and skin proteins of weanling rats was studied during zinc restriction. Reduced incorporation of labeled proline into skin proteins including collagen hydroxyproline and an increase in its incorporation into liver and plasma proteins was observed with 0 or 0.046 mumol zinc/g diet, compared with 0.092, 0.153 or 0.306 mumol/g diet. Food (energy) restriction was then compared with zinc restriction, during recovery from protein restriction. A shift in proline incorporation from skin protein and skin collagen hydroxyproline, towards liver and plasma proteins, was closely correlated with body weight gain, whether it was limited by zinc restriction or by energy restriction. This diversion of label from skin to liver and plasma is probably mediated through mechanisms that limit growth during food restriction. Proline-incorporation patterns during zinc or energy restriction are clearly different from those of vitamin-C deficiency in guinea pigs.

Effect of vitamin C on sorbitol in the lens of guinea-pigs made diabetic with streptozotocin

Marginally vitamin C-deficient guinea-pigs treated with the diabetogenic agent streptozotocin were compared with those liberally supplied with vitamin C, for functional indices of vitamin C status, particularly in the eye lens. Weanling male Dunkin-Hartley guinea-pigs were fed on diets with 0.1 g vitamin C/kg (marginally deficient), or 5 g/kg (liberally supplied), and some received intraperitoneal streptozotocin (two doses of 150 mg/kg body-weight). About half the streptozotocin-treated animals had high urinary glucose following an oral glucose dose; these animals also grew more slowly than the others. At 4 months after streptozotocin the animals were killed for measurement of tissue vitamin C, glucose and sorbitol. Streptozotocin moderately increased the concentration of glucose in plasma, lens and aqueous humour. Lens sorbitol levels increased only in the group exposed to streptozotocin plus marginal vitamin C. There was a significant (P less than 0.02) positive correlation between urinary glucose and lens sorbitol levels overall. Liberal vitamin C intake may thus counteract the effect of streptozotocin diabetes on lens sorbitol, suggesting a new function of vitamin C, possibly related to cataractogenesis and to the biochemical lesions associated with diabetes.

Oxidative damage in Alzheimer's dementia, and the potential etiopathogenic role of aluminosilicates, microglia and micronutrient interactions

While evidence implicating free radical oxidative processes in the etiopathogenesis of Alzheimer's dementia is accumulating, the specific cellular and biochemical mechanisms involved remain to be identified. The potential pathogenic role of microglial cells in neurodegenerative processes is indicated by the finding that purified murine microglial cells exposed in vitro to various model aluminosilicate particles stimulate the generation of tissue-injurious free radical reactive oxygen metabolites. Analogous inorganic aluminosilicate deposits have been reported to occur in the core of the characteristic senile plaques found in the brains of Alzheimer disease subjects. The possible modulation of free radical oxidative activity by antioxidant micronutrients and pharmacological agents, provides a rational basis for further preventative and therapeutic clinical investigations.

High folate intakes related to zinc status in preterm infants

The former practice of giving 1 mg (2.27 mumoles) oral folic acid daily to premature infants receiving enteral feeds was assessed with respect to zinc status in Cambridge, United Kingdom. A group of 60 preterm infants, 80% of whom were receiving 1 mg oral folic acid daily, were studied for up to the first 16 weeks of life. Plasma folate and plasma zinc were measured for each subject. A significant inverse relationship was found between the maximum attained serum folate level and the minimum attained serum zinc level, (t = 5.0, 58 df, P less than 0.0001). This remained significant after corrections had been made for gestational age at birth, fetal growth retardation, birth weight, sex, diet, assisted ventilation and length of time to full enteral feeding. The hypothesis that very high folate intakes may adversely affect serum zinc levels and, by inference, zinc status in preterm infants could not be rejected. Caution is therefore advised when prescribing such very high folate doses daily for small preterm infants.

Cephaloconiosis: a free radical perspective on the proposed particulate-induced etiopathogenesis of Alzheimer's dementia and related disorders

By analogy to the etiology of the pneumoconioses, exogenous dust-induced diseases of the lung, and endogenous crystal-induced arthropathies such as gout, it is proposed that Alzheimer's dementia and allied disorders are causally related to the accumulation of fibriform inorganic deposits within the brain. Hence the neonosological term 'Cephaloconiosis'. It is proposed that: 1) either by the extrinsic migration or intrinsic formation and deposition of insoluble and persistent inorganic reactive nidi, the particle-induced generation of tissue-damaging free-radical oxygen metabolites by stimulated brain glial macrophage-type and allied phagocytic cells, provides a rationale for the etiopathogenesis of neurodegenerative processes; 2) the modulation of the injurious oxidative metabolic reaction by micronutrient and pharmacological antioxidant agents is a rational and potentially feasible strategy for future therapeutic clinical investigations.

The use of computed tomography in assessing oral cancer recurrence after flap reconstruction

Following radiation treatment, ablative surgery, and surgical flap reconstruction in cases of oral cancer, postoperative follow-up for oral cancer recurrence presents a difficult task. Computed tomography (CT) remains the most accessible method of postoperative assessment; however, it has yet to be conclusively shown to provide an advantage over an adequate history and physical examination. Twenty-four consecutive patients who had undergone flap reconstruction of the oral cavity for advanced or radiorecurrent disease were studied over an 18-month period. Eight patients showed no evidence of recurrent tumor either clinically or by CT scan. Eleven patients had evidence of recurrent disease clinically, which was confirmed by CT. In four patients, clinically unsuspected regional recurrent tumor was revealed by CT. One false negative scan was encountered. CT proved to be a sensitive modality for detecting clinically unsuspected recurrences, particularly regional recurrences.

Alzheimer's disease: a pathogenic role for aluminosilicate-induced phagocytic free radicals

The occurrence of aluminosilicate deposits within the cerebral plaques in Alzheimer's senile dementia sufferers has prompted further consideration of the possible role of such materials in the aetiology and pathogenesis of the disease. We have monitored the ability of various natural and synthetic model aluminosilicate particulates of differing morphological and chemical composition to stimulate the generation of phagocyte-derived free radical reactive oxygen metabolites (ROM) using an in vitro chemiluminescent technique on purified human blood-derived polymorphonuclear leukocytes (PMN). The results indicate that an enhanced chemiluminescent response is produced by calcium-bearing fibriform particulates. It is proposed that an analogous in vivo particle-induced and phagocyte-mediated oxidative stress could provide a potential pathogenic mechanism in the development of Alzheimer's disease.

Environmental cancer, phagocytic oxidant stress and nutritional interactions

Environmental exposure to inhaled mineral dusts is associated with a variety of inflammatory, fibrotic and carcinogenic pulmonary diseases, generally characterized by the infiltration into the lung of phagocytic cells, namely macrophages and polymorphonuclear leucocytes (PMN). The ability of pathogenic mineral, fibrous and metalliferous dusts to stimulate PMN to produce potentially injurious free radical oxidants, has been studied using an in vitro chemiluminescent technique. The cellular mechanisms and nutritional agents involved in providing the pulmonary antioxidant biochemical defence systems are reviewed, and the prospects of dietary modification of environmentally induced lung cancers and related pneumoconiotic diseases discussed.

The effects of dietary folate and zinc on the outcome of pregnancy and early growth in rats

1. The objective of the present study was to determine the effects of two levels of folic acid and two levels of zinc in the diets of rats during pregnancy and lactation. It addressed, among other things, the question of whether an inhibitory effect of folic (pteroylmonoglutamic) acid on Zn absorption might result in a secondary Zn deficiency in either the dams or the pups. 2. A purified diet was given to four groups of female DNL (Norwegian) Hooded rats, before and during pregnancy and during lactation. It contained the four possible combinations of: no added folic acid or 100 micrograms added pteroylmonoglutamic acid/g, and 6.6 or 20.2 micrograms Zn/g. Pups and dams were killed on day 20 of gestation or on day 20 postpartum. Measurements of body-weights, food intakes, blood folate and tissue Zn levels were performed. 3. The group with low Zn and low folate intake had a satisfactory reproductive outcome, and there were only minor effects of the supplements on body-weights. 4. Additional folate greatly increased blood (erythrocyte and plasma) folate levels, but did not compromise tissue Zn concentrations. Zn supplementation also enhanced blood folate levels, for reasons which are not yet clear. 5. There was a moderate enhancing effect of the Zn supplement on Zn levels in the livers and kidneys of pregnant dams, and the kidneys of lactating dams. 6. If the conclusions can be extrapolated to humans, then the results provide some reassurance that a high folate intake from prenatal supplementation need not necessarily cause Zn depletion, and hence functional Zn deficiency in pregnant women and their offspring.

Thallphytic Alleopathy: Isolation and Identification of Laetisaric Acid

Laetisaria arvalis, a soil-dwelling basidiomycete fungus, secretes an allelopathic agent that induces rapid hyphal lysis in several phytopathogenic fungi. The active compound was isolated from chloroform:methanol extracts ofL. arvalismycelia and characterized as a previously unknown hydroxy fatty acid, (Z,Z-9,12-8-hydroxyoctadecadienoic acid.

In vitro biological effects of volcanic ash from Mount Sakurajima

Mount Sakurajima in the south of the Kyushu Island of Japan erupts hundreds of times a year and continuously emits large amounts of ash. More than a million people live under this ash plume, and there is considerable concern about the possible effects of this on their health. We have studied the physicochemical characteristics and in vitro effects of airborne ash collected at 8 km from the crater. More than 30% of the ash was found to be SiO2 (w/w) with most of the particles within the respirable size range. The ash did not inhibit the colony formation of V79-4 cells and failed to activate complement or generate chemotactic factor activity in samples of fresh human serum. It was minimally active in causing the release of lysosomal enzymes from human neutrophile, and did not cause arachidonic acid release from macrophage-like cells. These results were in accord with our epidemiological study, in which very low prevalences of nonspecific respiratory disease were demonstrated even at the area with highest ash exposure.

Modification of the in vitro activities of amosite asbestos by surface derivatization

The in vitro cytotoxicity of amosite asbestos and its silanized and bovine serum albumin conjugated derivatives were studied in two cell lines. The overall cytotoxicity of amosite towards Chinese hamster lung cells (V79-4) was not affected by derivatization, although the rate of cell-particle interaction was reduced. Protein derivatization virtually abolished the cytolytic action of amosite to the macrophage-like cell line (P388D1), although this derivatized material still induced the release of arachidonate. These results confirm that the in vitro cytotoxic effect of fibrous particulates toward V79-4 cells is mainly dependent on fiber size, while the response of macrophage-like cells is more sensitive to alterations in surface chemistry. The relationship between these results and the pathogenicity of asbestos is discussed.

Natural and Synthetic Allatotoxins: Suicide Substrates for Juvenile Hormone Biosynthesis

Cytotoxic agents with antijuvenile hormone activity in insects have been discovered. Their mechanism of action may involve an oxidative bioactivation into a reactive quinone methide.