The relationship between gender and age with monocyte tissue factor expression.

BACKGROUND: In normal healthy individuals, the level of tissue factor (TF) expression on monocytes is low. However, studies have shown that patients with cardiovascular disease (CVD) have elevated levels of TF. As the risk of CVD increases with age and is more prominent in the male population, it is postulated that TF expression may be positively correlated with these factors. However, very few studies have examined the relationship between age and gender on TF expression. METHODS: This study evaluated the influence of age and gender on TF expression using data obtained from female (n = 44) and male (n = 27) subjects. We also examined the influence of BMI and total fat intake on TF expression in the same subjects. RESULTS: The results of our study found no significant difference in TF expression between the male and female subgroups. No correlation was found between TF and age, BMI or total fat intake in the male or female groupings. CONCLUSION: It may be postulated that the risk of CVD development in such populations may not be due to increases in TF expression with increasing age or gender differences.

Zinc status and age-related changes in peripheral blood leukocyte subpopulations in healthy men and women aged 55-70 y: the ZENITH study.

OBJECTIVE: To determine zinc status and age-related changes in the immune function of healthy late-middle-aged men and women (aged 55-70 y). DESIGN: Observational study. SETTING: Population of Northern Ireland. SUBJECTS: Apparently healthy, free-living individuals (45 men, 48 women) aged 55-70 y. INTERVENTION: Zinc status markers were analysed by flame atomic absorption spectrometry and commercially available kits. Immune function was assessed by flow cytometry. RESULTS: Serum and erythrocyte zinc concentrations were 13.0 (s.d. 1.40) micromol/l and 222 (s.d. 48.2) micromol/l, respectively. Serum alkaline phosphatase (ALP) concentrations were 76.8 (s.d. 16.1) U/l; women showed significantly higher concentrations of ALP (P = 0.011). Women demonstrated (1) a significant inverse correlation in naive T lymphocytes, specifically naive T-helper lymphocytes (% expression, r = -0.364, P = 0.007 and absolute count, r = -0.275, P = 0.036) with age and (2) a significant positive correlation between late activation of T lymphocytes (% expression, r = 0.299, P = 0.019 and absolute count, r = 0.260, P = 0.039) with advancing age. Men demonstrated a significant positive correlation in the % expression of (CD3-/CD16+/CD56+) natural killer (NK) cells with age (r = 0.316, P = 0.017). CONCLUSIONS: Between the ages of 55 and 70 y, healthy individuals experience significant alterations in immune function; however, such changes appear largely sex specific. Given the reported importance of adequate zinc status in maintaining optimal immune function, further studies are required to explore the effect of enhanced zinc status on emerging immune deficiencies in cell-mediated immunity in healthy 55-70 y olds.

Annexin A2 expression during cellular differentiation in myeloid cell lines.

Annexin A2 is a calcium-dependent, phospholipid-binding protein found on many cell types. It consists of a short hydrophobic tail (Ser(2)-Asn(32)), which dictates its function, and a core domain (Phe(33)-Asp(339)), which is involved in phospholipid binding. Annexin A2 has been implicated in a number of biochemical processes, including cell proliferation, foetal immune tolerance, ion-channel activation, cell-cell interactions and the bridging of membranes. Annexin A2 is reported to be a powerful activator of plasminogen and, therefore, is implicated in many normal and pathological processes such as haemostasis and metastasis. Myeloid cell lines are used, extensively, to study many aspects of cellular proliferation, differentiation and function. In the present study, we have used flow cytometry and real-time PCR to investigate the role of annexin A2 expression in the proliferation and differentiation of a number of myeloid cell lines. The results demonstrated that annexin A2 expression was affected when the cells were induced to differentiate by stimulation with all-trans-retinoic acid. Annexin A2 may, therefore, be an important player in cellular differentiation and its disorders.

Plasma levels of the immunomodulatory cytokine interleukin-10 during normal human pregnancy: a longitudinal study.

Pregnancy is proposed to be a Th2 phenomenon, where Th2 cytokines inhibit Th1 responses to improve foetal survival. The importance of interleukin-10 (IL-10), an immunomodulatory cytokine produced by Th2 cells, in the maintenance of normal pregnancy is becoming increasingly apparent. In a longitudinal case-control study, the physiological effect of pregnancy on plasma IL-10 was investigated. The plasma concentration of IL-10 was determined using an ELISA technique in 99 pregnant women sampled at 12, 20 and 35 weeks of gestation, 38 non-pregnant control subjects sampled in parallel and in a subgroup of women sampled at 3 days post-partum (n, pregnant 21, non-pregnant 21). Plasma IL-10 was significantly higher in pregnant women at 12, 20 and 35 weeks of gestation (p<0.05, p<0.01 and p<0.0001, respectively), and in mothers post-delivery (p<0.01) when compared to non-pregnant control subjects. Furthermore, there was no significant effect of gestational time on IL-10 concentration. Results from the current study suggest that elevated IL-10 is a physiological consequence of normal healthy pregnancy. These findings help clarify previous conflicting results and establish a range for plasma levels of IL-10 in normal healthy pregnancy.

Copper supplementation has no effect on markers of DNA damage and liver function in healthy adults (FOODCUE project).

BACKGROUND/AIMS: Copper is routinely used in the laboratory to promote oxidation in vitro. However, copper concentrations are million-fold higher than physiological concentrations and, in contrast, accumulating evidence suggests that copper may have an antioxidant role in vivo. The aim of this study was to provide data on how increased intake of copper affected mononuclear leukocyte DNA damage and liver function in healthy young free-living men and women. METHODS: The study design was a double-blind repeated crossover trial with treatment and intervening placebo periods, each of 6 weeks' duration. The following supplementations were given orally in sequence: CuSO(4) at a dose of 3 mg copper/day and copper amino acid chelates at doses of 3 and 6 mg copper/day. Oxidative DNA damage was assessed using a modification of the alkaline Comet assay incorporating an endonuclease III digestion step. The assessment of liver function was by measurement of the liver enzymes, alanine aminotransferase and L-gamma-glutamyltransferase. RESULTS: There was no significant alteration in mononuclear leukocyte DNA damage or on liver function after 6 weeks of copper supplementation at two doses (3 and 6 mg/day). CONCLUSIONS: Copper supplementation (giving total copper intake at the highest level of 7 mg/day) did not induce DNA damage or adversely affect liver function in healthy adults.

Boron supplementation and activated factor VII in healthy men.

OBJECTIVE: The aim of the present study was to determine whether postprandial concentrations of the active component of serine protease coagulation factor VII (VIIa) were lowered by acute boron supplementation in vivo. DESIGN: An acute, randomized, placebo-controlled, double blind, cross-over study. SETTING: Free-living population. SUBJECTS: Fifteen apparently healthy men, aged 45-65 y. INTERVENTIONS: Subjects visited the centre on two occasions, with the study days separated by a minimum of 2 weeks. Following collection of a fasting blood sample, subjects received either placebo or acute bolus of 11.6 mg boron (given as 102.6 mg sodium tetraborate decahydrate) together with a standard fat-rich meal. Blood samples were obtained at 1, 2, 4 and 6 h after the administration of the test meal, during which time subjects were at liberty to consume deionized water only. Blood samples were assayed for concentrations of insulin, glucose, lipids and boron. Measurement of the concentration of activated factor VIIa and of factor VII antigen, and of the activity of coagulation factors VII, IX and X was also carried out. RESULTS: Plasma boron concentrations were significantly higher following consumption of the boron supplement compared with placebo (0.124+/-0.02 vs 0.008+/-0.01 mg/l; P< or =0.001). There was no significant effect of acute boron supplementation on plasma insulin and glucose concentration or on blood lipid or coagulation factor profile. Factor VIIa rose significantly following consumption of the high fat meal (1.05+/-0.07 vs 1.26+/-0.07; P< or =0.001), but this increase was not altered by boron supplementation. CONCLUSIONS: Results from this study suggest that acute boron supplementation (at 11.6 mg boron) does not alter the activity of factor VIIa following consumption of a high-fat meal. SPONSORSHIP: This work was funded by Borax Europe Ltd.

Soluble P-selectin levels during normal pregnancy: a longitudinal study.

OBJECTIVE: To investigate soluble P-selectin (sP-selectin) levels and platelet parameters in normal pregnant women compared with non-pregnant control subjects. DESIGN: A longitudinal case-control study. SETTING: Obstetric outpatient clinic in the Jubilee Maternity Hospital, Belfast. POPULATION: One hundred and twenty normal pregnant women and 41 non-pregnant age-matched control subjects. METHODS: The plasma concentration of sP-selectin in pregnant women sampled at 12, 20 and 35 weeks of gestation, and, in a subgroup at three days postpartum, and non-pregnant controls sampled in parallel, was determined using a commercial quantitative sandwich immunoassay kit. Platelet parameters on each blood sample were also recorded using a SYSMEX SE 9500 analyser. MAIN OUTCOME MEASURES: Plasma sP-selectin as a measure of platelet activation in normal pregnancy. RESULTS: Soluble P-selectin was significantly higher in pregnant women than in non-pregnant control subjects at 20 and 35 weeks of gestation, (P < 0.01, and P < 0.001, respectively). Correlation analyses showed positive correlation between sP-selectin and platelet count in pregnant women at 20 and 35 weeks of gestation (r = 0.247, P < 0.05 and r = 0.360, P < 0.001, respectively). Soluble P-selectin concentration per platelet was also significantly higher in pregnant women than in non-pregnant control subjects at 20 and 35 weeks of gestation (P < 0.001). CONCLUSIONS: Our results show that sP-selectin concentration is significantly higher in the second and third trimester of pregnancy when compared with non-pregnant control subjects sampled in parallel. This finding clarifies previous conflicting results on platelet activation in normal pregnancy, and is in agreement with those earlier studies which reported, using other methods, increased platelet activation in normal pregnancy.

Tissue factor expression on monocyte subpopulations during normal pregnancy.

Pregnancy is often referred to as a hypercoagulable state due to changes in the haemostatic system. Tissue factor (TF) is the initiator of blood clotting in vivo. The effect of pregnancy on monocyte TF expression was determined in a longitudinal case control study (89 pregnant, 39 non-pregnant). Using whole blood flow cytometry and CD14 as a monocyte marker, TF expression was measured on all CD14 positive, CD14Bright and CD14Dim cells. TF expression was significantly lower in pregnant women than in non-pregnant control subjects, on all CD14 positive cells at 20 and 35 weeks, on CD14Bright cells at 12 and 35 weeks and on CD14Dim cells at 20 weeks. Additionally, we report that a higher percentage of CD14Dim than CD14Bright cells express TF. These results suggest that, in order to maintain homeostasis in haemostasis in an otherwise hypercoagulable state, monocyte TF expression is reduced during normal pregnancy.

Bioavailability of n-3 polyunsaturated fatty acids (PUFA) in foods enriched with microencapsulated fish oil.

OBJECTIVE: Incorporation of fish oil into food products provides a means of increasing n-3 fatty acid intake, particularly in populations where fish consumption remains low. The aim of the present study was to evaluate the bioavailability of n-3 PUFA in microencapsulated fish-oil-enriched foods compared with an equal amount of n-3 PUFAs contained in fish oil capsules. METHODS: Twenty-five healthy female volunteers were randomly assigned to one of two groups for the 4-week intervention: one group received 0.9 g of n-3 PUFA/day as fish oil capsule (capsule group), while the second group (food group) received an equal amount of n-3 PUFA/day from enriched foods. Baseline and post-intervention samples were analysed for platelet fatty acid composition. RESULTS: There was no significant difference in the change in platelet arachidonic acid (AA), eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA) between the two groups following the intervention. CONCLUSIONS: The results indicate that n-3 PUFA from microencapsulated fish-oil-enriched foods are as bioavailable as n-3 PUFA in a capsule. Fortification of foods with microencapsulated fish oil, therefore, offers an effective way of increasing n-3 PUFA intakes and status in line with current dietary recommendations.

Response of putative indices of copper status to copper supplementation in human subjects.

No sensitive functional index is currently available to assess Cu status in healthy human populations. This study evaluated the effect of Cu supplementation on putative indices of Cu status in twelve women and twelve men, aged between 22 and 45 years, who participated in a double-blind placebo controlled crossover study. The study consisted of three 6-week supplementation regimens of 3 mg CuSO4, 3 mg Cu-glycine chelate and 6 mg Cu-glycine chelate, each separated by placebo periods of equal length. Women had significantly higher caeruloplasmin oxidase activity (P < 0.001), caeruloplasmin protein concentration (P < 0.05), and serum diamine oxidase activity (P < 0.01) at baseline than men. Erythrocyte and leucocyte superoxide dismutase activity, leucocyte cytochrome c oxidase activity, and erythrocyte glutathione peroxidase activity did not respond to Cu supplementation. Platelet cytochrome c oxidase activity was significantly higher (P < 0.01), after supplementation with 6 mg Cu-glycine chelate in the total group and in women but did not change in men. Caeruloplasmin oxidase activity was significantly higher (P < 0.05), in men after supplementation with 3 mg Cu-glycine chelate, while caeruloplasmin protein concentration was significantly lower in men after supplementation with 6 mg Cu-glycine chelate (P < 0.05). Serum diamine oxidase activity was significantly higher after all supplementation regimens in the total group and in both men and women (P < 0.01). These results indicate that serum diamine oxidase activity is sensitive to changes in dietary Cu intakes and may also have the potential to evaluate changes in Cu status in healthy adult human subjects.

The effect of low-dose fish oil supplementation on serum growth factors in healthy humans.

OBJECTIVE: To examine the effect of low-dose fish oil supplementation on specific growth factors, purported to play a central role in lesion formation, and also on the total growth factor activity of serum, as assessed by the induction of DNA synthesis in cultured human arterial smooth muscle cells. DESIGN: Randomized placebo-controlled double-blind intervention study. SETTING: Free-living population. SUBJECTS: Sixty-three healthy volunteers, 37 males and 26 females. INTERVENTIONS: Four treatment regimes with subjects receiving 0, 0.3,0.6 or 0.9 g/day of n-3 PUFA for an 8 week period. Blood samples were taken at baseline and following the 8 week intervention. All samples were analysed in batch following completion of the study. RESULTS: Consumption of fish oil had no effect on serum platelet-derived growth factor (PDGF), or transforming growth factor beta (TGFbeta) concentration. Furthermore, fish oil supplementation did not alter the total growth factor activity of serum. CONCLUSIONS: Results indicate that low-dose fish oil supplementation, equivalent to about two portions of fatty fish per week and providing less than 1 g n-3 PUFA/day, does not alter the levels of the major serum growth factors and does not modify total serum growth factor activity in healthy human volunteers. SPONSORSHIP: European Union shared cost project (FAIR-CT-95-0085).

Interactions between vitamins C and E in human subjects.

Despite convincing in vitro evidence, a vitamin C-E interaction has not been confirmed in vivo. This study was designed to examine the effects of supplementation with either vitamin C or E on their respective plasma concentrations, other antioxidants, lipids and some haemostatic variables. Fasting blood was collected before and after intervention from thirty healthy adults in a double-blinded crossover study. Baselines for measured variables were established after 2 weeks of placebo supplementation, followed by daily supplementation with 73.5 mg RRR-alpha-tocopherol acetate or 500 mg ascorbic acid, and placebo, for 6 weeks. A 2 month washout preceded supplement crossover. Mean values showed that plasma lipid standardised alpha-tocopherol increased with ascorbic acid supplementation: from 4.09 (sem 0.51) to 4.53 (sem 0.66) micromol/mmol total cholesterol plus triacylglycerol (P < 0.05), and plasma ascorbic acid increased from 62.8 (sem 14.9) to 101.3 (sem 22. 2) micromol/l (P < 0.005). Supplementation with (RRR)-alpha-tocopherol acetate increased plasma alpha-tocopherol from 26.8 (sem 3.9) to 32.2 (sem 3.8) micromol/l (P < 0.05), and lipid-standardised alpha-tocopherol from 4.12 (sem 0.48) to 5.38 (sem 0.52) micromol/mmol (P < 0.001). Mean plasma ascorbic acid also increased with vitamin E supplementation, from 64.4 (sem 13.3) to 76. 4 (sem 18.4) micromol/l (P < 0.05). Plasma ferric reducing (antioxidant) power and glutathione peroxidase (U/g haemoglobin) increased in both groups, while urate, total cholesterol and triacylglycerol levels decreased (P < 0.05 throughout). Results are supportive of an in vivo interaction between vitamins C and E.

Applications of computer-aided learning in biomedical sciences: considerations in design and evaluation.

Multimedia computer-aided learning (CAL) is an area that has become increasingly prevalent in biomedical science. Here we describe the advances that have taken place in the computing industry that have led to this trend. We also outline areas within the subject of biomedical science that can most benefit from using multimedia CAL as a teaching aid. Furthermore, issues concerning the design of CAL (i.e. iterative design, structure, development tools) are discussed. As the evaluation of CAL is an essential part of the iterative design process, we look at new approaches to evaluation that have emerged in response to the superficial focus on usability that many evaluations take.

Marginal copper deficiency and atherosclerosis.

Copper is an essential trace element in the maintenance of the cardiovascular system. Copper-deficient diets can elicit, in animals, structural and functional changes that are comparable to those observed in coronary heart disease. In this study, the effect of dietary-induced copper deficiency on aortic lesion development was measured by quantitative image analysis in C57BL/6 mice that are susceptible to diet-induced aortic lesions. The diets administered were severely copper deficient (0.2 mg/kg diet), marginally deficient (0.6 mg/kg diet), or copper adequate (6.0 mg/kg diet). Similarly, increased aortic lesion areas and elevated serum cholesterol were demonstrated in both deficient groups, compared with the copper-adequate group. Evidence for graded differences in copper status among the dietary groups was shown by the dose-response increase in liver copper concentration, copper-zinc superoxide dismutase and cytochrome-c oxidase activities, together with serum caeruloplasmin oxidase with increasing intakes of dietary copper. Despite the difference in copper status between the copper marginal and severely deficient groups, similar lesions found in both groups of mice suggest a threshold effect of copper deficiency on lesion formation.

Plasma diamine oxidase activity is greater in copper-adequate than copper-marginal or copper-deficient rats.

The object of this study was to determine whether serum diamine oxidase activity could distinguish among adequate, marginal and deficient copper status in rats. Male weanling Sprague-Dawley rats (n = 21) were randomly assigned to one of three dietary regimens, with copper concentrations of 0.52, 1.73 and 6.7 mg/kg diet. On completion of the study, body weights were significantly different among dietary groups, with copper-marginal rats displaying the highest mean weight and copper-deficient rats the lowest. Copper-deficient rats ate significantly less food than the other two groups. Rats fed the three diets had significantly different liver copper concentrations. Liver and heart superoxide dismutase and cytochrome c oxidase activities, and plasma ceruloplasmin and erythrocyte superoxide dismutase activities were significantly lower in the copper-deficient rats than in the other two groups. Plasma diamine oxidase activity was lower in both copper-deficient (0.18 +/- 0.11 U/L) and marginal (0.21 +/- 0.11 U/L) rats compared with copper-adequate rats (3.35 +/- 0.28 U/L). Of the biochemical indices measured, only liver copper concentration (-20%) and plasma diamine oxidase activity (-94%) differed between rats fed copper-marginal and copper-adequate diets. Plasma diamine oxidase activity, therefore, may be a sensitive functional biomarker of suboptimal copper status.

Effect of cholesterol feeding on DNA damage in male and female Syrian hamsters.

Cholesterol oxides are cytotoxic and have been implicated in many disease processes; however, it has been proposed that cholesterol oxides result from cholesterol acting as a sacrificial antioxidant. In this study, the effect of dietary cholesterol on DNA damage, assessed by the alkaline comet assay, was examined in male and female Syrian hamsters. Animals were fed ad libitum a modified AIN-76 diet (control) or a diet with 0.5% cholesterol for 10 weeks. Following the 10-week feeding period, there was no significant difference in body weight between cholesterol-fed and control animals. Cholesterol feeding resulted in significant liver hypertrophy, and increased plasma total and HDL cholesterol in both male and female animals compared with controls. There was no difference in liver cell DNA damage levels as measured by the comet assay. Heart cells from cholesterol-fed hamsters, however, showed a significant decrease in tail DNA (p = 0.050) indicating decreased damage compared with controls and a possible protective effect of cholesterol against DNA damage.

Monocyte tissue factor-like activity in post myocardial infarction patients.

It is widely recognized that thrombosis is the major event in the evolution of stable vascular disease to unstable ischaemic syndromes including myocardial infarction and stroke. The purpose of this case-control study was to establish clinical and laboratory data on the possible relationship between specific components of the haemostatic system and coronary heart disease. The procoagulant activity (PCA) of peripheral monocytes and polymorphonuclear neutrophils was assessed in 21 males who had suffered a myocardial infarction (MI) and in age-matched controls. In addition, total factor VII activity, fibrinogen, tissue factor pathway inhibitor (TFPI). D-dimers, tissue plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1), tumour necrosis factor-alpha (TNF-alpha) and full blood counts were measured. Post MI patients had significantly higher monocyte PCA, higher plasma concentrations of TFPI, fibrinogen, t-PA, T/P100 and also higher total white blood cell and neutrophil counts compared to age-matched controls. This elevated procoagulant state in post MI patients could further exacerbate the disease process and increase the risk of subsequent acute ischaemic events.

The assessment of platelet derived growth factor concentration in post myocardial infarction and stable angina patients.

Platelet derived growth factor (PDGF) has been implicated in the pathogenesis of atherosclerosis. PDGF is released by aggregating platelets and monocytes which gather around sites of arterial injury. In the study reported here the concentration of plasma PDGF was measured in post myocardial infarction (MI) patients (n = 28), angina patients (n = 25), and control subjects (n = 27). Venous blood samples were taken and the concentration of PDGF determined by an enzyme linked immunosorbent assay (ELISA). Plasma PDGF concentrations were significantly higher in the post MI group compared to both the control and angina groups (P < or = 0.05). The increase in PDGF concentration may be due to increased activation of platelets or monocytes since these two cells are major sources of plasma PDGF. High concentrations of PDGF in the circulation could further accelerate the progression of the disease.

Fish oil supplementation with and without added vitamin E differentially modulates plasma antioxidant concentrations in healthy women.

The purpose of this study was to assess the effect of fish oil with or without vitamin E on plasma vitamin antioxidants. Thirty-three apparently healthy women aged 18-28 yr were recruited from the university environs, and 30 completed the double-blinded, parallel design supplementation trial. Blood samples were collected at baseline (week 0) and following 28 d of supplementation with three capsules/d (0.8 g x 3) of either fish oil (FO) or FO with vitamin E (3 IU/g) (FOE). An additional blood sample was taken at day 91 (washout). Plasma antioxidant vitamins, fatty acid composition, and lipid peroxides were measured. Plasma alpha-tocopherol concentrations were increased significantly in both groups postsupplementation FO (P = 0.018) and FOE (P = 0.003) compared with baseline and washout values. Plasma retinol concentration was significantly increased (P = 0.034) compared with baseline and washout values following supplementation with FOE but not FO, while plasma beta-carotene was significantly increased (P = 0.036), compared with baseline and washout values, following supplementation with FO but not FOE. There was a trend (P = 0.059) toward decreased plasma ascorbic acid following FO supplementation compared with baseline and washout. Plasma lipid peroxides did not change following either supplementation. Results suggest that low-dose FO feeding with and without vitamin E differentially modulates plasma antioxidant vitamins but has no significant effect on lipid peroxidation.