Changes in the human mitochondrial genome after treatment of malignant disease

Mitochondrial DNA (mtDNA) is the only extrachromosomal DNA in human cells. The mitochondrial genome encodes essential information for the synthesis of the mitochondrial respiratory chain. Inherited defects of this genome are an important cause of human disease. In addition, the mitochondrial genome seems to be particularly prone to DNA damage and acquired mutations may have a role in ageing, cancer and neurodegeneration. We wished to determine if radiotherapy and chemotherapy used in the treatment of cancer could induce changes in the mitochondrial genome. Such changes would be an important genetic marker of DNA damage and may explain some of the adverse effects of treatment. We studied samples from patients who had received radiotherapy and chemotherapy for point mutations within the mtDNA control region, and for large-scale deletions. In blood samples from patients, we found a significantly increased number of point mutations compared to the control subjects. In muscle biopsies from 7 of 8 patients whom had received whole body irradiation as well as chemotherapy, the level of a specific mtDNA deletion was significantly greater than in control subjects. Our studies have shown that in patients who have been treated for cancer there is an increased level of mtDNA damage.

Complementary food supplements to achieve micronutrient adequacy for infants and young children

Many children in developing countries survive on a nutritionally inadequate diet. Dietary inadequacies during the complementary feeding period can be prevented by using complementary food supplements (CFSs) such as water dispersible or crushable micronutrient tablets, micronutrient sprinkles added to food just before feeding, or fortified spreads added to food just before feeding or fed as a snacks. A meeting was convened to discuss technical and operational issues related to the development of these new approaches and to identify knowledge gaps. The technical issues covered: what micronutrients to include, tolerable upper intake limits, bioavailability, micronutrient and macronutrient stability, package systems and amounts, encapsulation technologies, methods to limit or eliminate allergens, bacterial and chemical contamination, interactions between CFSs and complementary foods, and flavoring agents. Operational issues included: identifying the market positioning of CFSs, cost positioning of CFSs, regulatory requirements, CFS production and technology transfer, quality assurance, and public-private sector partnership and coordination. Intervention trials are needed to determine the efficacy of CFSs in preventing micronutrient deficiencies. Other important knowledge gaps relate to technical and operational issues. Sprinkles and tablets are produced using well-known technologies, but further research is needed to modify them for use as CFSs. Spread development is not as advanced as sprinkle and tablet development, and further research is needed to improve the technology. Although none of the products is ready for widespread use, enough information is available to set research priorities and accelerate product development and implementation.

Linear programming: a mathematical tool for analyzing and optimizing children's diets during the complementary feeding period

During the complementary feeding period, children require a nutrient-dense diet to meet their high nutritional requirements. International interest exists in the promotion of affordable, nutritionally adequate complementary feeding diets based on locally available foods. In this context, two questions are often asked: 1) is it possible to design a diet suitable for the complementary feeding period using locally available food? and 2) if this is possible, what is the lowest-cost, nutritionally adequate diet available? These questions are usually answered using a "trial and error" approach. However, a more efficient and rigorous technique, based on linear programming, is also available. It has become more readily accessible with the advent of powerful personal computers. The purpose of this review, therefore, is to inform pediatricians and public health professionals about this tool. In this review, the basic principles of linear programming are briefly examined and some practical applications for formulating sound food-based nutritional recommendations in different contexts are explained. This review should facilitate the adoption of this technique by international health professionals.

Transvaginal ultrasound-guided oocyte aspiration for production of embryos <i>in vitro</i>

Abstract. reproductive potential in genetically valuable animals (BEAL et al., 1992). Now that repeatable oocyte retrieval methods are being fine-tuned, it is likely these procedures will become routinely used to obtain oocytes for further gamete and embryo research and also by seedstock producers for in vitro embryo production from farm animals in the commercial sector. The use of transvaginal ultrasound-guided oocyte aspiration and IVF procedure does offer an alternative to cattle producers who have genetically valuable cows that for some reason are unable to produce viable embryos through standard embryo collection procedures. This technology can be used on oocytes harvested from older ovulating or nonovulating cows, females with physical injuries (e.g., fractured leg) and problem cows having an abnormal cervix. Good success has been reported using IVF procedures on oocytes obtained from supplemental follicles of cows with cystic ovarian disease. With IVF the potential exists for more embryos to be produced in a shorter period of time, since the procedure can be repeated on the same cow 3 to 4 times or more a month. At this station, we are harvesting oocytes from early postpartum (< 40 days) beef and dairy cattle, before the female begins cyclic activity. The approach allows the opportunity to produce one or more extra calves from the cow before she is mated for a natural pregnancy. Currently, transvaginal ultrasound-guided oocyte aspiration is now being used to harvest valuable oocytes from minor farm animal breeds, from domestic females representing rare bloodlines, clinically infertile females and reproductively senescent cows. Research continues to find applications for this technology, including harvesting oocytes from young prepubertal heifers and early postpartum beef cows for in vitro embryo production. The use of ultrasound-guided oocyte aspiration should not be overlooked to obtain oocytes for in vitro embryo production and to aid in germplasm preservation of endangered exotic species.

Linear and nonlinear programming to optimize the nutrient density of a population's diet: an example based on diets of preschool children in rural Malawi

BACKGROUND

Food consumption surveys are often used to detect inadequate nutrient intakes but not to determine whether inadequate nutrient intakes are due to suboptimal use of locally available foods or to insufficient availability of nutrient-dense foods.

OBJECTIVES

The objectives were to describe the use of linear programming as a method to design nutrient-adequate diets of optimal nutrient density and to identify the most stringent constraints in nutritional recommendations and food consumption patterns in a population's diet.

DESIGN

This analysis was conducted with the use of food consumption data collected during 2 seasons from rural Malawian children aged 3-6 y. Linear programming was used to select diets based on local foods that satisfied a set of nutritional constraints while minimizing the total energy content of the diet. Additional constraints on daily intakes of foods and food groups were also introduced to ensure that the diets were compatible with local food patterns. The strength of the constraints was assessed by analyzing nonlinear programming sensitivity.

RESULTS

In the harvest season, it was possible to satisfy nutritional recommendations with little departure from the local diet. In the nonharvest season, nutritional adequacy was impaired by the low availability of riboflavin- and zinc-rich animal or vegetable foods and by the high phytate content of other foods.

CONCLUSIONS

This analysis suggests that nutrition education may help improve the diets of children in the harvest season, whereas changes in the range of available foods might be needed in the nonharvest season. Linear and nonlinear programming can be used to formulate recommendations with the use of data from local food consumption surveys.

'Leaving a mark'

Biopsies by various means do have a risk of seeding tumour cells into the biopsy track. Even with fine needle and trocar techniques this has been proven to occur. By excising the biopsy track at the time of surgery this risk can be reduced. With needle and trocar techniques there might be little evidence of the puncture when the time of surgery takes place. We advocate using Indian ink to mark the biopsy site.

Theoretical accounts of Gulf War Syndrome: from environmental toxins to psychoneuroimmunology and neurodegeneration

Non-specific illness includes a wide variety of symptoms: behavioural (e.g., reduced food and water intake), cognitive (e.g., memory and concentration problems) and physiological (e.g., fever). This paper reviews evidence suggesting that such symptoms can be explained more parsimoniously as a single symptom cluster than as a set of separate illnesses such as Gulf War Syndrome (GWS) and chronic fatigue syndrome (CFS). This superordinate syndrome could have its biological basis in the activity of pro-inflammatory cytokines (in particular interleukin-1: IL-1), that give rise to what has become known as the 'sickness response'. It is further argued that the persistence of non-specific illness in chronic conditions like GWS may be (in part) attributable to a bio-associative mechanism (Ferguson and Cassaday, 1999). In the case of GWS, physiological challenges could have produced a non-specific sickness response that became associated with smells (e.g., petrol), coincidentally experienced in the Persian Gulf. On returning to the home environment, these same smells would act as associative triggers for the maintenance of (conditioned) sickness responses. Such associative mechanisms could be mediated through the hypothalamus and limbic system via vagal nerve innervation and would provide an explanation for the persistence of a set of symptoms (e.g., fever) that should normally be short lived and self-limiting. We also present evidence that the pattern of symptoms produced by the pro-inflammatory cytokines reflects a shift in immune system functioning towards a (T-helper-1) Th1 profile. This position contrasts with other immunological accounts of GWS that suggest that the immune system demonstrates a shift to a Th2 (allergy) profile. Evidence pertaining to these two contrasting positions is reviewed.

Confidence in the safety of blood for transfusion: the effect of message framing

BACKGROUND

Blood transfusion is a universally used, life-saving medical intervention. However, there are increasing concerns among patients about blood safety. This study investigates the effect of message framing, a means of presenting information, on confidence in blood transfusion safety.

STUDY DESIGN AND METHODS

The same factual information regarding the safety of blood for transfusion was presented to a sample of 254 adult students (donors and nondonors) as either a gain frame (lives saved), a loss frame (lives lost), or a combined frame (a loss frame expressed in a positive context). This provided a basic two-way, between-subjects design with 1) blood donation history (donors vs. nondonors) and 2) message frame (gain, loss, and combined) functioning as the between-groups factors. It was hypothesized that participants would consider blood safer if information was presented as a gain frame. The role of stress appraisals as potential mediators of the framing effect was also explored.

RESULTS

As predicted, participants receiving the gain-frame information were significantly more confident of the safety of blood for transfusion than those receiving loss-frame information or both. This was unaffected by donation history or appraisals of stress associated with transfusion. The extent to which blood was considered safe was negatively associated, independently of framing effects, with perceptions that transfusion was threatening.

CONCLUSION

Information about transfusion should be conveyed to patients in a form focusing on the positive, rather than the negative, known facts about the safety of blood.

Intellect and somatic health: associations with hypochondriacal concerns, perceived threat and fainting

BACKGROUND

: Compared to the other domains of the Big 5, intellect has been relatively underresearched with regard to somatic health outcomes. It is argued that this, in part, is because specific hypotheses concerning intellect and somatic health have not been formulated. It is argued that intellect is related to both alexithymia and hypnotic ability. As such the High Risk Model of Threat Perception forms one useful theoretical framework for generating hypotheses about intellect and somatic health. On this basis it is hypothesised that intellect should show a U-shaped relationship to hypochondriacal concerns, a positive association with appraisals of threat and loss, and a negative association with levels of self-reported vasovagal syncope (feelings of faintness).

METHODS

Two cross-sectional studies, using student samples (n = 205, 179), examined the relationships between intellect and hypochondriacal concerns as well as intellect and appraisals of threat and loss. A third prospective study, using a sample of blood donors (n = 373), examined the relationship between levels of self-reported vasovagal syncope and intellect.

RESULTS

Compared to the other domains of the Big 5, intellect demonstrated a U-shaped association with hypochondriacal concerns, a positive association with perceived threat and loss and a negative association with fainting. The negative association with fainting remained once incidence of previous fainting, the number of previous blood donations and emotional stability were held as covariates.

CONCLUSIONS

Intellect is associated in a number of important ways with a variety of psychosomatic variables.

RNA expression in the early characterization of hepatotoxicants in Wistar rats by high-density DNA microarrays

High-density microarrays are useful tools to study gene expression for the purpose of characterizing functional tissue changes in response to the action of drugs and chemicals. To test whether high-density expression data can identify mechanisms of toxicity and to identify an unknown sample through its RNA expression pattern, groups of male Wistar rats were administered 6 hepatotoxicants. The compounds chosen for this study were microcystin-LR (MLR), phenobarbital (PB), lipopolysaccharide (LPS), carbon tetrachloride (CT), thioacetamide (THA), and cyproterone acetate (CPA). These hepatotoxicants are known to induce adverse liver effects through different mechanisms. Liver mRNA was isolated and used to generate biotinylated cRNA for hybridization to a custom 1,600-rat gene DNA microarray. Treatment correlation matrices analyzed hybridization data from a hepatotoxicant-blinded sample, with gene expression coefficients (GEC) evaluated by means of hierarchical cluster analysis and visual representation as dendrograms. The experimental liver toxicity from the different treatments was confirmed by means of concurrent histopathology, liver enzymes, and bilirubin assays. This toxico genomic analysis identified multiple genes and groups of genes that were affected by the hepatotoxicants on study, indicating that high-density microarray expression data are useful to identify groups of genes involved in toxicity. In addition, the mRNA expression profile of an unidentified sample can be accurately identified when compared with the expression profiles resident in the data set. This study supports the use of gene expression-profiling technology to determine or to predict toxic liver effects.

Sex and sexual orientation: the effect of group membership on individuals' judgments about self and others' HIV risk

No previous study has directly compared homosexual and heterosexual men and women's perceptions of HIV risk. In fact, empirical research focusing on homosexual women's perception of HIV risk is scarce. This paper, therefore, examines whether homosexual and heterosexual women and men (N = 60) make varied self and other (peer and non-peer) HIV risk judgments. The paper also examines the roles of motivational (health anxiety) and cognitive (HIV knowledge) factors in relation to HIV risk judgments. The results show that each group held different perceptions of risk for various "other" groups. Only homosexual men showed evidence for an optimistic bias, whereas homosexual women showed evidence of realistic perceptions. Both cognitive and motivational factors were shown to be associated with risk judgments for homosexual women and heterosexual men. Methodologically the use of Multidimensional scaling as an analytic strategy is recommended.

Hypochondriacal concerns, somatosensory amplification, and primary and secondary cognitive appraisals

This paper uses data from four studies (N = 150, 150, 154 and 79) to examine the associations between hypochondriacal concerns (HCs) and stress appraisals (primary and secondary). A search activity account of HCs suggests that increased levels of HCs should be associated with positive appraisals of a stressful situation (i.e., increased levels of perceived challenge and perceived control). However, the results indicated that in terms of primary appraisals, increased perceptions of threat and not challenge were consistently associated with increased levels of HCs. Further, the results indicated that the association between threat and HCs is mediated by somatosensory amplification. Consistent with the search activity account it is shown that increased levels of perceived control (secondary appraisals) are associated with increased levels of HCs. The association for perceived control remains once variance due to somatosensory amplification is partialled and generalizes to a sample of patients with a sexually transmitted infection. The results are interpreted in relation to the transactional model of the stress process.

Hypochondriacal concerns and the five factor model of personality

Using data from two studies (Ns = 205 and 161), this article examines the associations between the domains of the five factor model of personality and hypochondriacal concerns (HCs). These associations are explored once covariation due to other related traits (somatosensory amplification) and comorbidity factors (anxiety, depression, and somatic symptom reporting) have been controlled. As predicted, emotional stability was associated with most criteria related to HCs and agreeableness was negatively associated with the perceived inadequacy of a physician's explanation. Conscientiousness was negatively associated with HCs. These associations remained after partialing the comorbidity factors and somatosensory amplification. The discussion focuses on the particular role of agreeableness and conscientiousness in relation to HCs.

Associations between primary appraisals and life-events while controlling for depression

OBJECTIVES

The main objective of this paper was to explore the associations between life-events and primary appraisals (threat, challenge and loss) controlling for depression. It was predicted that specific associations between life-events and primary appraisals would remain once depression had been partialled. A subgoal of this paper was to develop a content analytic coding frame for student life-events.

DESIGN

This study was a retrospective survey in which participants provided accounts of recent stressful encounters, and completed indices of primary appraisals and depression.

METHOD

The participants were 979 undergraduates who provided descriptions of life-events. A subsample of 391 provided additional information on primary appraisals and depression. The primary outcomes were the partial correlations between life-events and primary appraisals.

RESULTS

There were significant associations between life-events and primary appraisals above and beyond variance explained by depression. Results also indicated that the definition of loss appraisals could be extended to include events that were related to anticipated future loss, especially if the event was also perceived as threatening. Also certain self-defined negative life-events were appraised as positive. Life-events were shown to vary systematically as a function of external constraints (e.g. stage of the academic year).

CONCLUSIONS

A variety of events were associated with loss appraisals and this may have implications for risk factors in depression.

A competency model for general practice: implications for selection, training, and development

BACKGROUND

The role of the general practitioner (GP) has changed significantly over the past decade. This problem is compounded by growing concern over postgraduate attrition rates from medicine, with current estimates as high as 19%.

AIM

To define a comprehensive model of the competencies required for the job role of GP.

METHOD

Three independent studies were conducted to define GP competencies including (1) critical incidents focus groups with GPs, (2) behavioural coding of GP-patient consultations, and (3) critical incidents interviews with patients. Study 1 was conducted with GPs (n = 35) from the Trent region. Study 2 involved observation of GP-patient consultations (n = 33 consultations), and Study 3 was conducted with patients (n = 21), all from a Midlands-based medical practice.

RESULTS

The data collected from the three studies provided strong evidence for a competency model comprising 11 categories with a summary of the associated behavioural descriptions. Example competencies included empathy and sensitivity, communication skills, clinical knowledge and expertise, conceptual thinking, and coping with pressure.

CONCLUSIONS

Triangulation of results was achieved from three independent studies. The competencies derived imply that a greater account of personal attributes needs to be considered in recruitment and training, rather than focusing on academic and clinical competency alone. The model could be employed for future research in design of selection techniques for the role of GP.

Pupils' causal attributions for difficult classroom behaviour

BACKGROUND

Studies of causal attributions within educational contexts have tended to concentrate on academic performance. There have been a smaller number of investigations of teachers' attributions for pupils' behaviour in school.

AIMS

The present study examines the causal attribution made by pupils for difficult behaviour in classrooms. It reveals the structure of these attributions and serves as a comparison with the teacher studies.

SAMPLE

The participants were 105 pupils (52 males and 53 females) in the first year of secondary schooling, all drawn from the same inner city school.

METHOD

Four initial small group interviews were used to identify a wide range of factors that pupils viewed as being causes of difficult classroom behaviour in the 18 primary schools they had previously attended. A questionnaire was then constructed incorporating items from these discussions and administered to the whole of the year group of pupils, but omitting the participants in the initial group discussions.

RESULTS

The results of a factor analysis indicated that pupils' attributions for misbehaviour at school were best represented by four factors: (1) 'fairness of teacher's actions', (2) 'pupil vulnerability', (3) 'adverse family circumstances' and (4) 'strictness of classroom regime'. While there were no gender differences, pupils saw the 'fairness of teacher's actions' and 'pupil vulnerability' as more significant contributors to pupil misbehaviour than either 'adverse family circumstances' or 'strictness of classroom regime'.

CONCLUSION

The attributions by pupils for difficult classroom behaviour differ markedly from those obtained in studies of teachers. Policy and practice initiatives which do not attend to conflicting attributional styles are unlikely to succeed in improving levels of pupil behaviour in schools.

The surgical management of bacterial valvular endocarditis

Bacterial endocarditis is an important cause of cardiac valvular problems. The diagnosis of bacterial endocarditis can be difficult, and, often, an aggressive clinical evaluation including serial blood cultures is necessary. The pathophysiology of endocarditis is changing with the rise of intravenous drug use; staphylococci are an increasingly common cause. Endocarditis often warrants surgical intervention. Operations for bacterial endocarditis range from valve repair to valve replacement to homograft replacement. The operations are technically challenging, but new methods of myocardial protection have markedly improved the surgical outcomes. Valve excision is an option for intravenous drug users with tricuspid valve endocarditis. Surgical management of endocarditis is a technically challenging but rewarding procedure that should be offered to appropriate patients.

The Gulf War and illness by association

The symptoms of Gulf War Syndrome (GWS) closely correspond to the physiological and behavioural sequelae of an interleukin-1 (IL-1) mediated sickness response. We propose that this response can account for the variability in its symptomatology. Furthermore, the persistence of GWS can be accounted for by an associative process, whereby the smells/tastes of war become linked with the physiological reaction to environmental stressors encountered in the Gulf and/or the 'cocktail' of drugs given to the soldiers. As required, the IL-1 response is conditionable.

Role of electrophilic and general base catalysis in the mechanism of Escherichia coli uracil DNA glycosylase

Escherichia coli uracil DNA glycosylase (UDG) catalyzes the hydrolysis of premutagenic uracil bases in DNA by flipping the deoxyuridine from the DNA helix [Stivers, J. T., et al. (1999) Biochemistry 38, 952]. A general acid-base mechanism has been proposed whereby His187 facilitates leaving group departure by protonating the O2 of uracil and Asp64 activates a water molecule for nucleophilic attack at C1' of the deoxyribose. Detailed kinetic studies on the H187Q, H187A, and D64N mutant enzymes indicate that Asp64 and His187 stabilize the chemical transition state by 5.3 and 4.8 kcal/mol, respectively, with little effect on substrate or product binding. The pH dependence of k(cat) for wild-type and H187Q UDG indicates that an unprotonated group in the enzyme-substrate complex (pK(a) = 6.2 +/- 0.2) is required for catalysis. This unprotonated group has a small DeltaH of ionization (-0.4 +/- 1.7 kcal/mol) and is absent in the pH profile for D64N UDG, suggesting that it corresponds to the general base Asp64. The pH dependence of k(cat) for wild-type, H187Q, and D64N UDG shows no evidence for an essential protonated group over the pH range of 5.5-10. Hence, the pK(a) of His187 must be outside this pH range if it serves as an electrophilic catalyst. These results support a mechanism in which Asp64 serves as the general base and His187 acts as a neutral electrophile, stabilizing a developing negative charge on uracil O2 in the transition state. In the following paper of this issue we establish by crystallography and heteronuclear NMR spectroscopy that the imidazole of His187 is neutral during the catalytic cycle of UDG.

Characterization of the adduct formed from the reaction between homocysteine thiolactone and low-density lipoprotein: antioxidant implications

Homocysteine thiolactone is a cyclic thioester that is implicated in the development of atherosclerosis. This molecule will readily acylate primary amines, forming a homocystamide adduct, which contains a primary amine and a thiol. Here, we have characterized and evaluated the antioxidant potential of the homocystamide-low-density lipoprotein (LDL) adduct, a product of the reaction between homocysteine thiolactone and LDL. Treatment of LDL with homocysteine thiolactone resulted in a time-dependent increase in LDL-bound thiols that reached approximately 250 nmol thiol/mg LDL protein. The thiol groups of the homocystamide-LDL adduct were labeled with the thiol-reactive nitroxide, methanethiosulfonate spin label. Using paramagnetic relaxing agents and the electron spin resonance spin labeling technique, we determined that the homocystamide adducts were predominately exposed to the aqueous phase. The homocystamide-LDL adduct was resistant to myoglobin- and Cu2(+)-mediated oxidation (with respect to native LDL), as measured by the formation of conjugated dienes and thiobarbituric acid reactive substances, and the depletion of vitamin E. This antioxidant effect was due to increased thiol content, as the effect was abolished with N-ethylmaleamide pre-treatment. We conclude that the reaction between homocysteine thiolactone and LDL generates an LDL molecule that is more resistant to oxidative modification than native LDL. The potential relationship between the homocystamide-LDL adduct and the development of atherosclerosis is discussed.

Hypochondriacal concerns, symptom reporting and secondary gain mechanisms

Hypochondriacal concerns (HCs) and somatic symptom reporting (SSR) are associated. However, HCs are believed to be linked to the ego-defence coping strategy of avoiding help and SSR is believed to be linked to secondary gain. One hundred and twenty undergraduate students completed measures of HCs, SSR and the Desire for Control (DC) Scale. Subscales of the DC scale were used as indices of help avoidance and secondary gain. Both hierarchical multiple linear regression and LISREL structural modelling were used to control for the confound between HCs and SSR and explore the links with help avoidance and secondary gain. HCs were found to be primarily associated with an increased desire to strive for independence (avoid help) and levels of SSR were associated with the desire to have others make decisions (secondary gain).

Generation and initial characterization of a novel polyclonal antibody directed against homocysteine thiolactone-modified low density lipoprotein

Elevated plasma homocysteine (homocysteinemia) are presumed to be responsible for the development of coronary artery disease, however, the precise etiology is unclear. We examined the possibility that the adduct formed from the reaction between homocysteine thiolactone, a metabolic product of homocysteine, and apolipoprotein B-100 lysyl residues of low density lipoprotein (LDL) was immunogenic. New Zealand White rabbits were immunized with this adduct at 6-week intervals. Antisera collected following the 3rd immunization was assayed for antibody titers using solid phase ELISA techniques. Titers (defined as the inverse of the greatest serum dilution in which there was a significant difference (P < 0.05) between the percentage antibody bound from the antiserum and the pre-immune serum) were approximately 10(5). In competition-based ELISAs, homocysteine thiolactone-treated LDL competed for binding with the antiserum, as the 50% inhibitory concentration was approximately 10 microg/ml. Neither homocysteine, homocystine (homocysteine disulfide), nor Cu2-oxidized LDL competed for binding. LDL in which lysyl residues were derivatized by acetylation or methylation were not recognized by the antiserum. Homocysteine thiolactone-treated plasma competed for binding to the antiserum, whereas native plasma did not. All lipoprotein fractions from the homocysteine thiolactone-treated plasma competed for binding to the antiserum. We conclude that homocysteine thiolactone-modified LDL is highly immunogenic and specific for homocysteine thiolactone-modified lysines. The potential for using this antibody as a diagnostic tool for measuring plasma homocysteine concentrations and the implications for understanding diseases induced by homocysteinemia are discussed.

Nurses' evaluations of sources of information about HIV and AIDS

Reviews of the literature indicate that nurses feel ill-informed about HIV/AIDS and that poor knowledge is associated with anxiety and negative attitudes towards infected patients and their care. Although some studies have sought to identify the sources of HIV/AIDS information available to nurses, few have attempted to understand how nurses evaluate such sources. In this study in 1992, 15 sources of HIV/AIDS information were identified during group discussions with nursing staff and nurse tutors. 277 nursing staff evaluated each of the sources in terms of perceived frequency (how often the source is used) and six items chosen to assess the usability and usefulness of each source (e.g. how informative the source is, how easy it is to understand). The results indicate that in-service training, basic training and professional colleagues are the sources evaluated most highly while posters and advertisements, television and radio and popular newspapers are the most frequently used sources of information. Trades unions' journals and pamphlets are the least frequently used sources of information and receive only modest evaluations. 20% of respondents report never having received any training regarding HIV and AIDS. Implications for the future provision of HIV/AIDS information and directions for further research are discussed.

The mechanism of apolipoprotein B-100 thiol depletion during oxidative modification of low-density lipoprotein

Oxidation of low-density lipoprotein (LDL) is recognized to be a key step in atherogenesis. Previous studies show that LDL contains low-molecular-weight antioxidants such as vitamin E, beta-carotene, and ubiquinol, which can retard oxidative modification. In this report, we have evaluated the antioxidant potential of apolipoprotein B-100 (apo-B) thiols during LDL oxidation. Both apo-B thiols and vitamin E were depleted concomitantly during the lag phase of Cu(2+)-mediated LDL oxidation. The rate of thiol depletion was significantly inhibited by the lipophilic spin trap N-tert-butyl-alpha-phenylnitrone (PBN) but not by the water-soluble spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN). Blocking apo-B thiols with sulfhydryl modifying agents increased the oxidizability of LDL. As with Cu2+, peroxynitrite also caused depletion of apo-B thiols, and again thiol depletion was inhibited by PBN but not by POBN. A PBN/lipid-derived radical adduct was observed by the electron spin resonance technique during oxidation of LDL with peroxynitrite. We conclude that apo-B thiol depletion is mediated by lipid peroxidation, prior to the onset of the propagation phase of LDL oxidation. The implications of apo-B thiols an intrinsic antioxidants of LDL are discussed.

Stress and blood donation: effects of music and previous donation experience

Making a blood donation, especially for first-time donors, can be a stressful experience. These feelings of stress may inhibit donors from returning. This paper applies stress theory to this particular problem. The effects of a stress management intervention (the provision of music) and previous donor experience were examined in relation to pre- and post-donation mood, environmental appraisals and coping behaviour. Results indicated that the provision of music had detrimental effects on environmental appraisals for those who have donated up to two times previously, but beneficial effects for those who had donated three times before. These effects were, to an extent, moderated by coping processes but not perceived control. It is recommended that the provision of music is not used as a stress management technique in the context of blood donation.

Selective inhibition of tumor necrosis factor-induced vascular cell adhesion molecule-1 gene expression by a novel flavonoid. Lack of effect on transcription factor NF-kappa B

In the present studies, we examined the effect of flavonoids on the endothelial cell expression of adhesion molecules, an early step in inflammation and atherogenesis. Addition of tumor necrosis factor-alpha (TNF) to human aortic endothelial cells (HAECs) led to the induction of vascular cell adhesion molecule-1 (VCAM-1) expression and enhancement in expression of intercellular adhesion molecule-1 (ICAM-1). A flavonoid, 2-(3-amino-phenyl)-8-methoxy-chromene-4-one (PD 098063), markedly inhibited TNF-induced VCAM-1 cell-surface expression in a concentration-dependent fashion with half-maximal inhibition at 19 mumol/L but had no effect on ICAM-1 expression. Another structurally distinct flavonoid, 2-phenyl-chromene-4-one, similarly selectively decreased VCAM-1 expression. The inhibition in cell-surface expression of VCAM-1 by PD 098063 correlated with decreases in steady-state mRNA levels, but there was no effect on ICAM-1 mRNA levels. The decrease in VCAM-1 mRNA levels was not due to changes in mRNA stability but rather resulted from a reduction in the rate of transcription of the gene. However, electrophoretic mobility shift assays using nuclear extracts from TNF-induced HAECs treated with PD 098063 failed to show a decrease in the activation of NF-kappa B, indicating that inhibition of activation of this transcription factor may not be its mode of action. Similarly, PD 098063 did not affect chloramphenicol acetyltransferase reporter gene activity in TNF-inducible minimal VCAM-1 promoter constructs containing two NF-kappa B sites, suggesting that the compound does not affect the transactivation driven by these sites. We conclude that this compound selectively blocks agonist-induced VCAM-1 protein and gene expression in HAECs by NF-kappa B-independent mechanism(s).

Comparison of measured and predicted creatinine excretion is an unreliable index of compliance in PD patients

OBJECTIVE

To evaluate the use of the ratio of measured to predicted creatinine excretion as an index of compliance in peritoneal dialysis (PD) patients.

DESIGN

A prospective analysis.

SETTING

Academic teaching hospital dialysis unit.

PATIENTS

Forty-three patients on PD.

MEASUREMENTS

Creatinine excretion in daily dialysate and urine collections was measured on one occasion in 10 patients and on two occasions in 33 patients, and, after adding an estimate for extrarenal creatinine degradation, was divided by predicted creatinine excretion to give a creatinine excretion ratio, which has been proposed as an index of compliance with exchanges in PD patients. Values above 1.24 have been suggested to indicate noncompliance. Lean body mass was also estimated from creatinine excretion.

RESULTS

The mean creatinine excretion ratio was 1.12, and 30% of patients had a value above 1.3. Only one patient admitted noncompliance. Studies on four consecutive days of guaranteed compliance in 7 patients with high ratios showed that creatinine excretion remained constant, suggesting that the patients were high creatinine producers rather than noncompliant. Creatinine excretion was stable when measured at intervals of days, but over months it tended to change markedly in many patients. Lean body mass estimations using creatinine excretion were low in most patients.

CONCLUSION

Comparison of measured and predicted creatinine excretion is not a reliable indicator of noncompliance because many compliant patients consistently excrete more creatinine than predicted. The standard formulas were not validated in dialysis patients and underestimate creatinine excretion significantly in many PD patients. Existing estimates in the literature of noncompliance, using this methodology, may not be accurate. Better methods of detecting this problem are required.

Identification of a novel 85-kDa lipoprotein lipase binding protein on human aortic endothelial cell surface

Lipoprotein lipase (LPL), bound to the luminal surface of vascular endothelium catalyzes lipoprotein triglyceride hydrolysis. Studies were performed to identify human aortic endothelial (HAEC) cell-surface proteins having high affinity for LPL. LPL-sepharose affinity chromatography of [35S]O4 labeled HAEC proteins identified a 220-kDa proteoglycan. Ligand blotting of HAEC plasma membrane proteins with LPL revealed two specific binding proteins of MW 116 kDa and 85 kDa, respectively, which were not released from the cell-surface by heparin treatment. Since the 220-kDa and 116-kDa proteins have been reported previously in bovine endothelial cells, we focused on the 85-kDa protein. The 85-kDa protein was not labelled by incubation of the cells with [35S]O4, suggesting that it is not a sulfated proteoglycan. Treatment of HAEC with tunicamycin markedly decreased detection of the 85-kDa protein, suggesting that it is likely a glycoprotein synthesized by HAEC. We conclude that HAEC cell surface has three specific LPL binding proteins, a 220-kDa proteoglycan, a 116-kDa protein and a novel 85-kDa protein.

Inhibition of tumor necrosis factor induced human aortic endothelial cell adhesion molecule gene expression by an alkoxybenzo[b]thiophene-2-carboxamide

The effects of a novel anti-inflammatory agent, 5-methoxy-3-(1-methyl-ethoxy)benzo[b]thiophene-2-carboxamide-1-oxide (PD 144795) on adhesion molecule expression in tumor necrosis factor (TNF) stimulated human aortic endothelial cells (HAEC) were examined. PD 144795 treatment markedly inhibited the TNF-induced cell expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) protein and mRNA. Gel shift assays using nuclear extracts from HAEC treated with PD 144795 failed to show a decrease in the activation of NFkB by this compound, whereas pyrrolidine dithiocarbamate (PDTC), an antioxidant, markedly inhibited the activation of this transcription factor. Thus, PD 144795 inhibits agonist-stimulated VCAM-1 and ICAM-1 expression likely via an NFkB independent mechanism, distinct from that of PDTC. Such agents may provide a novel approach for control of adhesion molecule gene expression in inflammation.

Factors affecting an individual's ability to administer medication

In this study, the authors identify how well self-care agents function in the self-administration of medication. The sample population included 60 adults who were evaluated on their ability to read three prescription labels and perform the tasks necessary to administer medications correctly. Age, gender, number of medications taken, and type of chronic disease did not contribute significantly to the ability to self-medicate correctly. Complexity of the medication regime and educational level were highly significant. Reading scores improved as educational levels increased; however, all educational groups had consistently lower performance scores compared with reading scores.

Apolipoprotein B and E basic amino acid clusters influence low-density lipoprotein association with lipoprotein lipase anchored to the subendothelial matrix

Lipoprotein accumulation in the subendothelial matrix is an important step in atherogenesis. We have previously shown that addition of lipoprotein lipase (LPL) markedly increased binding of apolipoprotein B (apoB)-containing lipoproteins to an endothelial cell-derived matrix, and this enhanced lipoprotein binding was inhibited by apoE. In the present studies we examined the role of various regions of apoB in the binding of LDL to LPL-containing endothelial cell matrix and the ability of various apoE domains to decrease lipoprotein retention. We studied three apoB epitope-specific monoclonal antibodies for their ability to block the binding of 125I-LDL to LPL-containing matrix. Of these, monoclonal antibody 4G3, which recognizes an arginine-containing epitope in apoB, was the most effective in reducing LDL binding. Chemical modification of LDL apoB lysines or arginines markedly reduced the ability of the lipoprotein to block the binding of 125I-LDL to LPL-containing matrix, suggesting that apoB positively charged amino acids are involved in the interaction. Furthermore, polyarginine or polylysine markedly decreased 125I-LDL binding to LPL-containing matrix, whereas polyleucine was ineffective. These data suggest that apoB positively charged regions are important in LDL binding. To explore the role of charge modifications on apoE by single arginine-cysteine interchanges, we examined the effects of the three major human apoE isoforms (apoE2, apoE3, and apoE4). ApoE3 was the most effective in decreasing 125I-LDL retention, followed by apoE4; apoE2 was the least effective. Similarly, apoE2-containing HDL was much less effective than apoE3-containing HDL in decreasing 125I-LDL retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Phosphonates and phosphinates: novel leaving groups for benzisothiazolone inhibitors of human leukocyte elastase

A novel class of alkyl and aryl phosphonate and phosphinate acid-based leaving groups has been developed for utilization in the synthesis of benzoisothiazolone (BIT) inhibitors of human leukocyte elastase (HLE). A number of BITs were synthesized with phosphonate and phosphinate acid-based leaving groups and were found to be potent inhibitors of HLE. Compound 3c with a diethyl phosphonate leaving group is the most potent inhibitor synthesized in this series with Ki* = 0.035 nM and ED50 = 2.0 mg/kg.

A measure of knowledge and confidence in relation to HIV and AIDS: reliability and validity

Knowledge of HIV and AIDS is widely seen as an important determinant of anxiety about such infection in health care workers. However, existing measures of this knowledge suffer from a number of methodological problems and few demonstrate adequate reliability and validity. This paper documents the development of a new measure detailing its reliability and validity. Knowledge, and also confidence in knowledge, were assessed across seven domains of relevant information (e.g. epidemiology, personal risk, symptomatology) in one non-expert group (non-medical undergraduate psychologist) and in three groups with greater expertise (nursing students and third year and final year medical students). The measure was shown to be reliable and to discriminate between the four groups in a manner consistent with the level of education received by each group and in terms of both the scale scores for the seven domains and the individual items. In general, final year medical students were shown to be more knowledgeable, and more confident in their knowledge, than the other groups. The non-medical undergraduates showed the lowest level of knowledge. In general, the groups appeared under-confident in their knowledge about HIV/AIDS. This was interpreted in terms of members of these groups exhibiting caution and the perceived fluctuating nature of the HIV knowledge base. Implications for the training of health care workers in relation to HIV/AIDS are discussed.

Canine atopic disease: the prevalence of positive intradermal skin tests at two sites in the north and south of Great Britain

Results of intradermal skin test responses to the same panel of 53 allergens were compared in 118 dogs with atopic disease presented at two geographical centres, Edinburgh (87 cases) and London (31 cases). The allergens most commonly positive at both centres were human dander and Dermatophagoides farinae, but positive tests to all of the allergens used occurred in at least one case. The mean number of allergens to which positive tests resulted in atopic dogs was 5.126 (Edinburgh) and 5.129 (London). The majority of animals were sensitive to allergens from more than one group. A significantly higher number of positive reactors to house dust allergen was observed at London than at Edinburgh (P < 0.05), while a significantly higher number of positive reactions to grass pollens was detected at Edinburgh than in London (P < 0.05). Sensitivity to Dermatophagoides pteronyssinus, in the absence of sensitivity to D. farinae, was uncommon and therefore both of these mite allergens should be incorporated in intradermal skin testing panels in Great Britain.

Acyl-coenzyme A:cholesterol-acyltransferase (ACAT) inhibitors modulate monocyte adhesion to aortic endothelial cells

Increased monocyte adhesion to aortic endothelium is observed in the pathogenesis of atherosclerosis. The role of endothelial acyl-coenzyme A:cholesterol-acyltransferase (ACAT) in the regulation of monocyte adhesion is not known. To examine the potential role of this enzyme in monocyte adhesion, a specific ACAT inhibitor, CI-976, was utilized. Although the basal adhesion of U937 monocytic cells to porcine aortic endothelial cells was low, treatment of the endothelial cells with lipopolysaccharide (LPS) markedly increased monocyte adhesion. Monocyte adhesion to LPS-treated endothelial cells was markedly inhibited by CI-976 treatment of the endothelial cells. Similarly, another ACAT inhibitor, PD 132301-2, whose structure is distinct from CI-976, also decreased monocyte adhesion. CI-976 treatment of endothelial cells also decreased endothelial cell ACAT activity. Since leukotriene B4 (LTB4) is known to promote leukocyte-endothelial cell adhesion, endothelial cell production of this leukotriene was examined after incubation with CI-976. CI-976 treatment markedly decreased LTB4 synthesis. Exogenous LTB4 addition to CI-976 treated cells reversed the effects of this compound on monocyte adhesion. These data demonstrate that ACAT inhibitors decrease monocyte adhesion to endothelial cells. Similar mechanisms may contribute to antiatherosclerotic effects of ACAT inhibitors in vivo.