Dietary supplementation with the anti-tumour promoter quercetin: its effects on matrix metalloproteinase gene regulation

Dietary modification, especially the consumption of larger amounts of fruits and vegetables can act to decrease the risk of a variety of human cancers. Quercetin, a bioflavonoid widely distributed in fruits and vegetables has been shown to have a chemoprotective role in cancer, through complex effects on signal transduction involved in cell proliferation and angiogenesis. In this study we examined the effects of dietary supplementation of quercetin (30 mg per day) incorporated into a black currant drink. Healthy male subjects aged between 33 and 64 years (mean=47.1 years) received either quercetin or placebo for 14 days. Blood samples were taken at baseline and upon completion of the study and analysed for full blood count, matrix metalloproteinase-2 (MMP-2), tissue inhibitor of matrix metalloproteinse-1 and -2 (TIMP-1 and -2) plasma levels using ELISA techniques. RNA was extracted from the peripheral blood lymphocytes and reverse transcriptase-polymerase chain reaction (RT-PCR) carried out for MMP-2 and TIMP-1, TIMP-2 gene expression determination. Supplementation of the diet with quercetin did not alter the MMP-2 or TIMP-2 gene transcription or plasma protein levels of the healthy subjects in this study. The TIMP-1 gene transcription and plasma protein levels (311+/-70 ng/ml at baseline to 183+/-35 ng/ml post-supplementation, P<0.05) of the subjects in this study were, however, significantly decreased following quercetin supplementation. This is an interesting result, as there is some controversy over the functions of TIMP-1 in tumour progression. In certain model systems, artificially increased TIMP-1 levels prevent or decrease tumour growth. However, in other studies high levels of TIMP-1 have been correlated with aggressive disease and poor prognosis in patients with certain malignancies. This study has outlined a potential role for the anti-tumour promoter quercetin as a dietary mediator of the carcinogenic cascade.

No significant effects of lutein, lycopene or beta-carotene supplementation on biological markers of oxidative stress and LDL oxidizability in healthy adult subjects

OBJECTIVE

The objective of this study was to determine the effect of individual carotenoid supplementation on biochemical indices of oxidative status in apparently healthy adult males.

METHODS

The study was a placebo controlled single blind study. Healthy male volunteers (n= 175) were assigned to four groups. They received daily supplements of beta-carotene (15 mg), lutein (15 mg), lycopene (15 mg) and placebo for three months. The effects of the supplementation on antioxidant status were monitored by plasma carotenoid, vitamin C and A levels, glutathione (GSH and GSSG) concentrations, protein SH groups. erythrocyte antioxidant enzyme activities (Cu-Zn SOD, Se-GSH-Px) and susceptibility of LDL to copper-induced oxidation.

RESULTS

beta-carotene, lycopene and lutein supplementation led to significant plasma and LDL increases in each of these carotenoids, without modifications of other carotenoid levels in plasma or in LDL. The supplementation failed to enhance the resistance of LDL to oxidation or to modify the LDL polyunsaturated/ saturated fatty acid ratio. Vitamin C, GSH, protein SH groups and antioxidant metalloenzyme activities were also unchanged.

CONCLUSION

We did not observe beneficial or adverse effects of lutein, lycopene or beta-carotene supplementation on biomarkers of oxidative stress. In apparently healthy subjects, carotenoid supplementation does not lead to significantly measurable improvement in antioxidant defenses.

Serum concentrations of carotenoids and vitamins A, E, and C in control subjects from five European countries

High intakes of fruits and vegetables, or high circulating levels of their biomarkers (carotenoids, vitamins C and E), have been associated with a relatively low incidence of cardiovascular disease, cataract and cancer. Exposure to a high fruit and vegetable diet increases antioxidant concentrations in blood and body tissues, and potentially protects against oxidative damage to cells and tissues. This paper describes blood concentrations of carotenoids, tocopherols, ascorbic acid and retinol in well-defined groups of healthy, non-smokers, aged 25-45 years, 175 men and 174 women from five European countries (France, UK (Northern Ireland), Republic of Ireland, The Netherlands and Spain). Analysis was centralised and performed within 18 months. Within-gender, vitamin C showed no significant differences between centres. Females in France, Republic of Ireland and Spain had significantly higher plasma vitamin C concentrations than their male counterparts. Serum retinol and alpha-tocopherol levels were similar between centres, but gamma-tocopherol showed a great variability being the lowest in Spain and France, and the highest in The Netherlands. The provitamin A: non-provitamin A carotenoid ratio was similar among countries, whereas the xanthophylls (lutein, zeaxanthin, beta-cryptoxanthin) to carotenes (alpha-carotene, beta-carotene, lycopene) ratio was double in southern (Spain) compared to the northern areas (Northern Ireland and Republic of Ireland). Serum concentrations of lutein and zeaxanthin were highest in France and Spain; beta-cryptoxanthin was highest in Spain and The Netherlands; trans-lycopene tended to be highest in Irish males and lowest in Spanish males; alpha-carotene and beta-carotene were higher in the French volunteers. Due to the study design, the concentrations of carotenoids and vitamins A, C and E represent physiological ranges achievable by dietary means and may be considered as 'reference values' in serum of healthy, non-smoking middle-aged subjects from five European countries. The results suggest that lutein (and zeaxanthin), beta-cryptoxanthin, total xanthophylls and gamma-tocopherol (and alpha- : gamma-tocopherol) may be important markers related to the healthy or protective effects of the Mediterranean-like diet.

Evaluating the clinical management of severely malnourished children--a study of two rural district hospitals

BACKGROUND

Severe malnutrition is an important cause of preventable mortality in most South African hospitals. Work recently done in two rural Eastern Cape hospitals supports the literature which shows that many deaths occur as a result of outdated clinical practices and that improving these practices reduces case fatality rates. Rapid assessment of clinical management in paediatric wards is necessary to highlight areas for improvement.

OBJECTIVE

To assess the management of severely malnourished children in two rural district hospitals and to recommend improvements for their care.

METHODS

Based on draft World Health Organisation (WHO) guidelines for inpatient care of children with severe malnutrition, data collection instruments were developed in conjunction with the district nutrition team to assess the quality of care given to malnourished children in two Mount Frere hospitals, Eastern Cape. Data were collected through retrospective review of case records, with detailed studies of selected cases, structured observations of the paediatric wards, and interviews with ward sisters and doctors.

RESULTS

The combined case fatality rate for severe malnutrition was 32%. Inadequate feeding, poor management of rehydration and infection, lack of resources, and a lack of knowledge and motivation among staff were identified as areas that need attention.

CONCLUSION

The clinical management of severely malnourished children can be rapidly assessed to highlight areas for improvement. Involving staff in the assessment process has led to their active involvement in improving the management of malnourished children in their hospitals.

Dialysis and gel filtration of isolated low density lipoproteins do not cause a significant loss of low density lipoprotein tocopherol and carotenoid concentration

The resistance of isolated low density lipoprotein (LDL) to copper-initiated oxidation is often used as a measure of effectiveness of an antioxidant intervention. Prior to oxidation, excess salt and EDTA are removed via dialysis or gel filtration of the LDL sample. However, there is concern over whether the antioxidant content of dialyzed or gel-filtered LDL is truly representative of native LDL extracted from a blood sample. Previously, the experiments done after the storage of native and dialyzed LDL at -80 degrees C showed that the dialysis step can cause a loss of up to 60% in the tocopherol and carotenoid content of LDL. In the present study, a comparison of the micronutrient concentration in freshly prepared dialyzed and native LDL from 35 subjects showed that after the correction for cholesterol, only lycopene (13%, P < 0.001) and to a lesser extent alpha-carotene (8%, P < 0.02) were significantly decreased, and the absolute fall in concentration was far smaller than previously reported. Other experiments done with smaller numbers of samples suggested that there were minimal micronutrient losses following gel filtration and that it was important to include 10 micromol/L EDTA in the dialysis and elution buffer; otherwise micronutrient losses did occur. In summary, immediate dialysis of freshly isolated LDL in the presence of 10 micromol/L EDTA does not cause any major loss in the concentration of tocopherol and most carotenoids.

Copper supplementation in humans does not affect the susceptibility of low density lipoprotein to in vitro induced oxidation (FOODCUE project)

The oxidative modification of low-density lipoprotein cholesterol (LDL) has been implicated in the pathogenesis of atherosclerosis. Copper (Cu) is essential for antioxidant enzymes in vivo and animal studies show that Cu deficiency is accompanied by increased atherogenesis and LDL susceptibility to oxidation. Nevertheless, Cu has been proposed as a pro-oxidant in vivo and is routinely used to induce lipid peroxidation in vitro. Given the dual role of Cu as an in vivo antioxidant and an in vitro pro-oxidant, a multicenter European study (FOODCUE) was instigated to provide data on the biological effects of increased dietary Cu. Four centers, Northern Ireland (coordinator), England, Denmark, and France, using different experimental protocols, examined the effect of Cu supplementation (3 or 6 mg/d) on top of normal Cu dietary intakes or Cu-controlled diets (0.7/1.6/6.0 mg/d), on Cu-mediated and peroxynitrite-initiated LDL oxidation in apparently healthy volunteers. Each center coordinated its own supplementation regimen and all samples were subsequently transported to Northern Ireland where lipid peroxidation analysis was completed. The results from all centers showed that dietary Cu supplementation had no effect on Cu- or peroxynitrite-induced LDL susceptibility to oxidation. These data show that high intakes (up to 6 mg Cu) for extended periods do not promote LDL susceptibility to in vitro-induced oxidation.

Consumption of tomato products with olive oil but not sunflower oil increases the antioxidant activity of plasma

Health benefits of lycopene from tomato products have been suggested to be related to its antioxidant activity. Dietary fat may influence the absorption and hence the plasma levels and antioxidant activity of lycopene. In the present study, we have compared the effect of consumption of tomato products with extra-virgin olive oil vs. tomato products plus sunflower oil on plasma lycopene and antioxidant levels. Results show that the oil composition does not affect the absorption of lycopene from tomato products because similar levels of plasma lycopene (mean +/- SD) were obtained on feeding tomatoes (providing approximately 46 mg lycopene/d) for 7 d with either olive oil (0.66 +/- 0.26 vs 1.20 +/- 0.20 micromol/l, p <.002) or sunflower oil (0.67 +/- 0.27 vs. 1.14 micromol/l, p <.001). However, consumption of tomato products with olive oil significantly raised the plasma antioxidant activity (FRAP) from 930 +/- 150 to 1118 +/- 184 micromol/l, p <.01) but no effect was observed when the sunflower oil was used. The change (supplementation minus start values) in FRAP following the consumption of tomato products with oil was significantly higher for olive oil (190 +/- 101) than for sunflower oil (-9.6 +/- 99, p <. 005). In conclusion, the results of the study show that consumption of tomato products with olive oil but not with sunflower oil improves the antioxidant activity of the plasma.

Influence of increased fruit and vegetable intake on plasma and lipoprotein carotenoids and LDL oxidation in smokers and nonsmokers

BACKGROUND

Epidemiological studies suggest a cardioprotective role for carotenoid-rich foods. Smokers have a high risk of cardiovascular disease and low dietary intake and plasma concentrations of carotenoids. The aim of this study was to determine the carotenoid response of smokers and nonsmokers to increased intake of 300-400 g of vegetables and its effect on LDL oxidation.

METHODS

After a depletion period of 8 days, 34 healthy females (18 nonsmokers, 16 smokers) were supplemented with beta-carotene- and lutein-rich (green) and lycopene-rich (red) vegetable foods, each for 7 days.

RESULTS

Baseline concentrations (mean +/- SD) of plasma beta-carotene (0.203+/-0.28 micromol/L vs. 0.412+/-0.34 micromol/L; P <0.005) and lutein (0.180 +/-0.10 vs. 0.242+/-0.11 micromol/L; P<0.05) but not lycopene (0.296+/-0.10 vs. 0.319+/-0.33 micromol/L) were significantly lower in smokers compared with nonsmokers. After supplementation, the change (supplementation minus depletion) in plasma beta-carotene (0.152+/- 0.43 vs. 0.363+/-0.29 micromol/L in smokers vs. nonsmokers; P = 0.002) and LDL lutein (0.015+/-0.03 vs. 0.029+/-0.03 micromol/mmol cholesterol; P = 0.01) was significantly lower in smokers than nonsmokers. Green-vegetable supplementation had no effect on the resistance of LDL to oxidation (lag-phase) in either group. After red-vegetable supplementation, plasma and LDL lycopene concentrations were increased in both groups, but only nonsmokers showed a significant increase in the lag-phase (44.9+/-9.5 min at baseline, 41.4+/-6.5 min after depletion, and 49.0+/-8.9 min after supplementation; P<0.01) compared with depletion.

CONCLUSIONS

In this short-term intervention study, a dietary intake of >40 mg/day of lycopene by a group of nonsmoking individuals significantly reduced the susceptibility of LDL to oxidation, whereas an equivalent increase in lycopene by a group of smokers showed no such effect.

Nonalcoholic red wine extract and quercetin inhibit LDL oxidation without affecting plasma antioxidant vitamin and carotenoid concentrations

BACKGROUND

Antioxidant enrichment of LDL can increase its resistance to oxidation and hence reduce its atherogenicity. The objective of the present study was to investigate whether in vivo supplementation with nonalcoholic red wine extract and quercetin can increase the oxidative resistance of LDL, and also whether the supplementation has any effect on other antioxidative micronutrients present in the blood.

METHODS

Twenty-one male subjects were supplemented with a placebo drink for 2 weeks and randomized into two groups. One group (n = 11) received the red wine extract (1 g/day, equivalent to 375 mL of red wine) and the other group (n = 10) quercetin (30 mg/day) for 2 weeks, followed by a 5-week washout period.

RESULTS

In the red wine extract-supplemented group, ex vivo copper-initiated oxidation of LDL (lag phase, mean +/- SD) was 40 +/- 11 min at the baseline, and increased significantly to 47 +/- 6 min [P <0.05 compared with placebo (38 +/- 4 min) and the washout values (40 +/- 5 min)]. In the quercetin-supplemented group, the lag phase was 44 +/- 11 and 40 +/- 5 min for the baseline and placebo, respectively, and increased significantly to 51 +/- 7 min [P <0.05 compared with placebo and washout (41 +/- 9 min)] after supplementation. Plasma lipids (triglycerides, total cholesterol, LDL- and HDL-cholesterol) did not change during the study period. Supplementation with red wine extract or quercetin had no effect on plasma vitamin C and E, retinol, and carotenoid concentrations.

CONCLUSIONS

Alcohol-free red wine extract and one of its components, quercetin, can inhibit LDL oxidation after in vivo supplementation; such "inhibition" is unrelated to changes in antioxidant vitamin and carotenoid concentrations.

Mutations affecting the delayed rectifier potassium current in Drosophila

Mutations and pharmacological agents have been used to resolve and analyze several K(+) currents in Drosophila. Mutations that affect channels carrying the voltage-activated I(A) and the Ca(2+) -activated I(CF) have helped greatly in analyzing the structure, function and regulation of these channels. We now report mutations that selectively affect the delayed rectifier current, I(K). Flies mutagenized with ethylmethanesulfonate were screened for temperature-induced paralysis. Paralytic mutants identified in the screen were examined for K(+) currents in the larval body-wall muscles. The z66 mutant larvae showed a significant reduction in I(K). The mutation did not affect other K(+) currents (I(A), I(CF), or I(CS) ) or the Ca(2+) channel current in the muscles. Another mutation, z4, which showed reduced I(K), failed to complement z66. Genetic analysis localized the gene disrupted by z66 and z4 to the left arm of chromosome 3, in the 63A1-63B6 region on polytene chromosomes. The z66 and the z4 mutations, which lie in the Shab K(+) channel gene, provide an opportunity to undertake analysis of the functioning of these channels and to study the role of these channels in membrane excitability.

Obsessive compulsive disorder: serotonin and beyond

OCD was considered a rare, treatment refractory disorder of psychological origin, up until 20 years ago. Research in the last two decades has altered the perspectives regarding OCD. It is now clear that OCD is a prevalent disorder--about 2% of the population suffer from OCD--and that it is amenable both to psychological (cognitive-behavioural approach) and pharmacological intervention (with serotonergic medication). The biochemical and neuroanatomical (the frontal basal-thalamo cortical circuit) pathophysiology of OCD is also beginning to emerge. OCD is unique with regards to its specific response to serotonergic medication that blocks reuptake. Clomiprimine, fluoxetine, fluvoxemine, paroxetine, sertraline and citalopram were all found to be effective treatments for OCD based on large, multicentre, double-blind, placebo-controlled studies. As only serotonergic medications appear to be effective in OCD, the serotonergic hypothesis has been formulated and tested. Indeed, pharmacological challenges with specific serotonin agonists such as mCPP and sumatriptan, which were associated with transient exacerbation of OCD symptoms, are in line with the specific role of 5HT in the pathogenesis of OCD. However, this serotonergic hypothesis, while necessary, is not sufficient. It is clear that the dopaminergic and autoimmune mechanism are also implicated in the pathogenesis of OCD. Further studies are required to understand the relevance of the serotonergic and non-serotonergic systems in OCD, and to highlight the various possible subtypes of this intriguing disorder.

The role of restricted motility in determining outcomes for vertical strabismus surgery in Graves' ophthalmology

OBJECTIVE

To identify factors predictive of operative success or failure for vertical muscle surgery performed in patients with Graves' ophthalmopathy.

DESIGN

Prospective noncomparative case series.

PARTICIPANTS

Thirty-one consecutive patients with Graves' ophthalmopathy who demonstrated vertical ocular motor imbalance, with or without simultaneous horizontal muscle imbalance.

INTERVENTION

Vertical extraocular muscle surgery performed either in isolation or in association with horizontal muscle surgery.

MAIN OUTCOME MEASUREMENTS

Vertical limitations of extraocular muscles were correlated with preoperative hypertropia. Stepwise linear regression was used to determine the significant predictors of postoperative hypertropia in primary gaze. Logistic analysis was used to estimate the probability of surgical failure (>5 diopters) on the basis of preoperative parameters.

RESULTS

The amount of preoperative hypertropia was negatively correlated with total restriction of vertical ductions (r = -0.52, P < 0.01). Preoperative hypertropia was positively correlated with asymmetry in muscle restriction between the two eyes (r = 0.67, P < 0.0001). The best predictor of preoperative hypertropia was the difference between restriction of the contralateral opposing recti, namely the right superior rectus, and the left inferior rectus, as well as the right inferior rectus and the left superior rectus (r = 0.74, P < 0.0001). Restriction of the contralateral opposing recti was also the most significant predictor of surgical success (postoperative hypertropia < 5 prism diopters).

CONCLUSIONS

Surgery tailored to address restriction of ductions, specifically the difference between contralateral opposing recti, is likely to improve the success of initial surgery beyond that based primarily on the magnitude of the vertical deviation.

Antioxidants and lipoprotein metabolism

Lipoprotein metabolism plays a significant role in the pathogenesis of atherosclerosis and risk of vascular disease. Elevated levels of LDL and low levels of HDL are linked to the risk of cardiovascular disease. It is now widely accepted that oxidative modification of LDL affects the metabolism of lipoproteins, leading to their increased accumulation in arterial intima. The present paper will examine some of the accumulating evidence from studies showing relationships between dietary intake of antioxidant nutrients, i.e. vitamins E and C, the carotenoids and the flavonoids, and their influence on lipoprotein metabolism. In particular, the present paper will review the available literature on the affect of antioxidant supplementation on lipoprotein oxidation, and hence metabolism of LDL in human subjects.

A mutation affecting dihydropyridine-sensitive current levels and activation kinetics in Drosophila muscle and mammalian heart calcium channels

The Dmca1D gene encodes a Drosophila calcium channel alpha1 subunit. We describe the first functional characterization of a mutation in this gene. This alpha1 subunit mediates the dihydropyridine-sensitive calcium channel current in larval muscle but does not contribute to the amiloride-sensitive current in that tissue. A mutation, which changes a highly conserved Cys to Tyr in transmembrane domain IS1, identifies a residue important for channel function not only in Drosophila muscle but also in mammalian cardiac channels. In both cases, mutations in this Cys residue slow channel activation and reduce expressed currents. Amino acid substitutions at this Cys position in the cardiac alpha1 subunit show that the size of the side chain, rather than its ability to form disulfide bonds, affects channel activation.

Paediatric admissions to a rural South African hospital: value of hospital data in helping to define intervention priorities and allocate district resources

OBJECTIVE

To audit paediatric medical admissions to a rural district hospital in order to help define intervention priorities and allocate district resources.

DESIGN

Prospective audit of consecutive admissions to the paediatric medical service of Hlabisa Hospital, KwaZulu-Natal, between March 1995 and February 1996.

MAIN OUTCOME MEASURES

Number of admissions, month of admission, age, sex, diagnosis, nutritional status, HIV status, outcome and length of stay.

RESULTS

Of 1,364 children admitted, 995 (73%) were aged under 24 months and 584 (43%) were either underweight for age or severely malnourished. Acute respiratory tract infection (384, 28%), acute diarrhoea (200, 15%), dysentery (168, 12%) and severe malnutrition (149, 11%) were the major causes for admission and were responsible for most deaths (113, 75%). The overall case fatality rate was 11% and most (90, 60%) died within 48 hours of admission. Forty-five per cent of the 332 children tested were HIV-positive.

CONCLUSION

Most severe morbidity and mortality result from four common conditions, reflecting poor socioeconomic conditions in the area. Opportunities for clincial intervention to reduce their impact include identification of 'at risk' children, focusing care early in admissions, use of standardised protocols of care, and integrated management of the sick child.