Polychlorinated biphenyls (PCBs) in fish-eating sea birds—II. Molecular features of PCB isomers and congeners in adipose tissue of male and female puffins (Fratercula arctica), guillemots (Uria aalga), shags (Phalacrocorax aristotelis) and cormorants (Phalacrocorax carbo) of British and Irish coastal waters

1. The concentration of individual PCBs was measured in adipose tissue of male and female puffins, shags, guillemots and cormorants obtained from the Isle of May and the Saltees islands.2. The concentrations of total PCBs showed positive correlations with that ofp,p'-DDE in the tissues.3. Enrichment factors were calculated by comparing the concentration of an individual PCB in the tissue with its abundance in commercial mixtures of PCBs.4. Of the 47 individual PCBs identified five prominent PCBs had enrichment factors considerably > 1 and accounted for approximately 35% of the total concentration of PCBs present. They shared the common molecular feature of chlorine atoms at adjacent meta-para positions in at least one of the biphenyl rings.5. Many PCBs had enrichment factors of <1, which suggested that they had been subjected to metabolism and presumably excretion. They shared the common feature of the absence of chlorine atoms at the meta-para positions of the biphenyl rings.6. These results support strongly the structural “rules” suggested in the preceding paper (Borlakoglu et al., 1990a) for the tendency of individual PCBs to accumulate or to be subjected to metabolism.     

Polychlorinated biphenyls (pcbs) in fish-eating sea birds—III. Molecular features and metabolic interpretations of PCB isomers and congeners in adipose tissues

1. Enrichment factors have been calculated for several persistent PCB congeners in the adipose tissue for five species of fish-eating sea birds (female razorbills, puffins, guillemots, shags and cormorants) obtained from the same sites during 1978–1984 (see preceding papers).2. The enrichment factor of an individual PCB is expressed as its concentration in the tissue compared with its abundance in commerical mixtures of PCBs or compared with the concentration in the tissue of the abundant congener 2,2',4,4',5,5'-hexachlorobiphenyl (congener 153, IUPAC system of numbering).3. There were no significant differences between the five species in the enrichment factor of individual persistent PCBs compared with congener 153, indicating similar levels of diminished metabolism of this group of congeners.4. Of the 47 individual PCBs identified, ten congeners had enrichment factors of > 1 in all of the species and these accounted for up to 70% of the concentration of total PCBs present. Some of these persistent congeners had approximately coplanar configurations (i.e. non-ortho -substituted congeners). Five congeners, which accounted for about 35% of the total concentration of PCBs in the tissues, shared the molecular feature of chlorine substituents at adjacent meta-para carbon atoms.5. A number of congeners were identified with enrichment factors of <1 compared with their abundance in Aroclor 1260, and very striking differences were observed between the five species in the ratio of non-persistent congeners to the persistent congener 153. These non-persistent congeners share the molecular feature of at least one pair of adjacent unsubstituted meta-para carbon atoms in the rings. This agrees with our molecular “rule” (see preceding papers) that congeners with this structural feature are subjected to metabolism by the cytochrome P-450 component of hepatic microsomal monooxygenases.6. Evidence is presented that this molecular rule applies to the persistence or non-persistence of classes of PCBs in other biological systems and that the complete absence of H atoms at adjacent carbon atoms is an essential structural requirement for the accumulation of PCBs in tissues.7. The persistence or non-persistence of individual PCBs is compared with their ability to induce specific isoforms of the cytochrome P-450 components of hepatic microsomal monooxygenases, and the toxic effects of individual PCBs that accumulate is discussed in terms of the potential environmental hazard that they represent.     

Polychlorinated biphenyls (PCBs) in fish-eating sea bird—I. Molecular features of PCB isomers and congeners in adipose tissue of male and female razorbills (Alca tarda) of British and Irish coastal waters

1. The concentration of individual PCBs was measured in adipose tissue of male and female razorbills obtained from the Isle of May and the Saltees islands.2. No significant differences were found in the concentration of total PCBs, which showed positive correlations with the concentration of p,p'-DDE in the tissues.3. Enrichment factors were calculated by comparing the concentration of an individual PCB in the tissue with its abundance in commercial mixtures of PCBs.4. Eight PCBs, together accounting for 20–65% of the concentration of total PCBs present, had enrichment factors of > 10. They had the common molecular feature of chlorine atoms at adjacent meta-para positions in at least one of the biphenyl rings.5. Many PCBs had enrichment factors of < 1, suggesting that they had been subjected to metabolism and presumably excretion. They had, in common, the absence of chlorine atoms at the meta-para positions of the biphenyl rings.     

Metabolism of di-, tri-, tetra-, penta- and hexachlorobiphenyls by hepatic microsomes isolated from control animals and animals treated with aroclor 1254, a commercial mixture of polychlorinated biphenyls (pcbs)

1. The metabolism of a wide range of di-, tri-, tetra-, penta- and hexachlorobiphenyls by hepatic microsomes isolated from control animals and animals treated with Aroclor 1254 was studied.2. Hepatic microsomes isolated from control rats expressed higher rates of oxidations than avians.3. Treatment of rats and pigeons with Aroclor 1254 induced cytochrome P450 dependent mono-oxygenases leading to an increased regioselective metabolism of PCB isomer and congeneres.4. There was an inverse relationship between the degree of halosubstitution and microsomal oxidation. Meta-para carbon atoms free of halosubstitution were the preferred side for oxidation.5. A good correlation was found between the in vitro metabolism of PCBs and their relative abundance in tissue extracts, thus suggesting oxidative metabolism to be the major route of metabolic disposal.     

The repeatability of feed intake and feed efficiency in beef cattle offered high-concentrate,grass silage and pasture-based diets

Breeding values for feed intake and feed efficiency in beef cattle are generally derived indoors on high-concentrate (HC) diets. Within temperate regions of north-western Europe, however, the majority of a growing beef animal’s lifetime dietary intake comes from grazed grass and grass silage. Using 97 growing beef cattle, the objective of the current study was to assess the repeatability of both feed intake and feed efficiency across 3 successive dietary test periods comprising grass silage plus concentrates (S+C), grazed grass (GRZ) and a HC diet. Individual DM intake (DMI), DMI/kg BW and feed efficiency-related parameters, residual feed intake (RFI) and gain to feed ratio (G : F) were assessed. There was a significant correlation for DMI between the S+C and GRZ periods (r = 0.32; P < 0.01) as well as between the S+C and HC periods (r = 0.41; P < 0.001), whereas there was no association for DMI between the GRZ and HC periods. There was a significant correlation for DMI/kg BW between the S+C and GRZ periods (r = 0.33; P < 0.01) and between the S+C and HC periods (r = 0.40; P < 0.001), but there was no association for the trait between the GRZ and HC periods. There was a significant correlation for RFI between the S+C and GRZ periods (r = 0.25; P < 0.05) as well as between S+C and HC periods (r = 0.25; P < 0.05), whereas there was no association for RFI between the GRZ and HC periods. Gain to feed ratio was not correlated between any of the test periods. A secondary aspect of the study demonstrated that traits recorded in the GRZ period relating to grazing bite rate, the number of daily grazing bouts and ruminating bouts were associated with DMI (r = 0.28 to 0.42; P < 0.05 - 0.001), DMI/kg BW (r = 0.36 to 0.45; P < 0.01 - 0.001) and RFI (r = 0.31 to 0.42; P < 0.05 - 0.001). Additionally, the number of ruminating boli produced per day and per ruminating bout were associated with G : F (r = 0.28 and 0.26, respectively; P < 0.05). Results from this study demonstrate that evaluating animals for both feed intake and feed efficiency indoors on HC diets may not reflect their phenotypic performance when consuming conserved forage-based diets indoors or when grazing pasture.     

Interrelations and associations of serum levels of steroids and pituitary hormones with markers of insulin resistance,inflammatory activity,and renal function in men and women aged >70 years in an 8-year longitudinal study of opposite-sex twins

Background: The physiological serum levels of steroids and pituitary hormones in older men and women have been sparsely reported in the literature.Objectives: The aims of this study were to investigate the normal variation and sex differences in steroids and pituitary hormones in those aged >70 years, and to study the interrelation between these hormones and indicators of the metabolic syndrome, inflammatory activity, and renal function.Methods: The investigation comprised a population-based sample of pairs of white opposite-sex twins from the Swedish Twin Registry. At baseline in 1996 and at the 8-year follow-uup in 2004, serum levels of progesterone, cortisol, testosterone, estradiol, follicle-stimulating hormone, luteinizing hormone, prolactin, creatinine, C-reactive protein (CRP), and urea were analyzed. Serum levels of insulin and cystatin were analyzed only at the follow-up.Results: The study sample included 219 men and 183 women aged 71 to 80 years (mean [SD], 74.5 [2.5] years) at baseline in 1996, and 127 men and 135 women at follow-uup in 2004. At baseline, in both men and women, the variation of progesterone in serum was positively correlated with that of estradiol (men: r = 0.226, P < 0.01; women: r = 0.115, P = NS), testosterone (men: r = 0.178, P < 0.01; women: r = 0.315, P < 0.001), and cortisol (men: r = 0.314, P < 0.001; women: r = 0.296, P < 0.001). The values of progesterone and other steroid hormones were associated with markers of insulin resistance (iie, insulin, waist circumference), inflammatory activity (ie, CRP) for progesterone (men: r = 0.267, P < 0.001; women: r = 0.150, P < 0.05), and renal function (ie, creatinine) for progesterone (men: r = 0.424, P < 0.001; women: r = 0.212, P < 0.01). Estradiol and prolactin were associated with insulin resistance, inflammation, and renal function. Furthermore, progesterone was associated with prolactin (men: r = 0.275, P < 0.001; women: r = 0.172, P < 0.05).. Among both men and women, there was a strong correlation between testosterone and estradiol (men: r = 0.753, P < 0.001; women: r = 0.526, P < 0.001); in women, there was also a link between testosterone and cortisol at follow-up (r = 0.340, P < 0.01). For progesterone, there was a significant correlation between the values of the co-twins (in 1996: r = 0.16, P < 0.05; in 2004: r = 0.45, P < 0.001). Higher serum levels of progesterone (2.0 [0.7] nmol/L in men and 1.7 [0.8] nmol/L in women) and prolactin (6 [5] μg/L in men and 8 [10] μg/L in women) were found among those who were deceased at follow-up compared with survivors (progesterone: 1.8 [0.5] nmol/L in men and 1.4 [0.6] nmol/L in women, P < 0.01; prolactin: 4 [3] μg/L in men and 5 [2] μg/L in women, P < 0.001).Conclusions: In this study of opposite-sex Swedish twins aged >70 years, there was a sex difference in the serum levels of steroids and pituitary hormones between men and women. Progesterone and other steroid hormones were associated with markers of insulin resistance, inflammatory activity, and renal function. Progesterone and prolactin levels were associated with increased risk of mortality in this sample.     

Oxidation of low-density lipoproteins: effect of antioxidant content,fatty acid composition and intrinsic phospholipase activity on susceptibility to metal ion-induced oxidation

The oxidative modification of low-density lipoprotein (LDL) may play an important role in atherogenesis. Our understanding of the mechanism of LDL oxidation and the factors that determine its susceptibility to oxidation is still incomplete. We have isolated LDL from 45 healthy individuals and studied the relationship between LDL fatty acid, vitamin E and β-carotene composition, intrinsic phospholipase A₂-like activity and parameters of LDL oxidation. LDL was exposed to a copper ion-dependent oxidising system and the kinetics of oxidation studied by monitoring formation of fatty acid conjugated dienes. The length of the lag phase of inhibited lipid peroxidation was measured as well as the rate of lipid peroxidation during the propagation phase. There was no significant correlation between LDL antioxidant vitamin or fatty acid composition and lag time to LDL oxidation. Oleic acid was negatively correlated with the rate of LDL oxidation (r = −0.41, P < 0.01) whilst linoleic acid was significantly correlated with the extent of LDL oxidation measured by the production of total dienes (r = 0.34, P < 0.05). Interestingly, LDL vitamin E content was positively correlated with both the rate (r = 0.28, P < 0.05) and extent of LDL oxidation (r = 0.43, P < 0.01). LDL isolated from this group of subjects showed significant intrinsic phospholipase-like activity. The phospholipase activity, whilst not correlated with lag time, was significantly correlated with both rate (r = 0.43, P < 0.01) and total diene production (r = 0.44, P < 0.01) of LDL oxidation. We conclude that antioxidant content, fatty acid composition and intrinsic phospholipase activity have little influence on the lag time of Cu-induced LDL oxidation. These components do however, significantly influence both the rate and extent of LDL oxidation, with increased vitamin E, linoleic acid content and phospholipase activity associated with faster and more extensive oxidation. The possible pro-oxidant effect of vitamin E has interesting implications for the postulated ‘protective’ effects of vitamin E on atherogenesis.     

Plasma progesterone concentration in relation to ovulation rate and embryo yield in Chios ewes superovulated with PMSG

The main purpose of this work was to investigate the relationship between plasma progesterone concentration and the number of ovulations and/or the number of embryos collected from Chios ewes induced to superovulate with various doses of PMSG.The oestrous cycles of the animals were synchronized by means of MAP intravaginal sponges for 14 days and PMSG was injected i.m. (1500 IU, Group 1; 1000 IU, Group 2; 750 IU, Group 3; 500 IU, Group 4; 0 IU, Group 5) at the time of sponge withdrawal. Seven days after sponge removal and 5 days after mating, mid-ventral laparotomy was performed and the uterine horns and/or oviducts were flushed. The number and diameter of corpora lutea (CL), the number of large (diameter > 0.5 cm) anovulated follicles and the total ovarian response (TOR = CL + large anovulated follicles) were recorded. The embryos were examined under a dissecting microscope and evaluated according to morphological criteria. Blood samples were collected once daily for 4 days starting on the day of sponge withdrawal. One more sample was taken on the day of embryo collection. Progesterone concentration was determined using a conventional ELISA.A significant positive correlation was found between plasma progesterone concentration and number of corpora lutea (r = 0.61, P < 0.001), total diameter of corpora lutea (r = 0.63, P < 0.001), total ovarian response (r = 0.63, P < 0.001), number of eggs (r = 0.51, P < 0.001), number of embryos (r = 0.43, P < 0.001) and number of transferable embryos (r = 0.36, P < 0.01) collected per ewe treated. A negative relation between progesterone concentration (≥ 2 ng ml⁻¹) at the beginning of oestrus and number of corpora lutea (CL) was observed. The investigation of the relationship between ovulation rate and plasma progesterone concentration on the day of embryo collection resulted in the calculation of a formula for the prediction of the response of Chios sheep after superovulation with the specific hormonal regimen.     

Mechanisms of hypocalcemia and markers of bone turnover in alcohol-intoxicated drinkers

Studies of hypocalcemia and osteoporosis frequently encountered in heavy users of alcohol have previously been performed on alcoholic people who have already recovered from alcohol intoxication. Bone and mineral metabolism during and after the intoxication may be different. We measured serum parameters of bone and mineral metabolism in 26 alcohol-intoxicated men and in 19 healthy control men. Although serum ionized calcium was 12% (P < 0.0001) lower in the patients than in the controls, serum intact parathyroid hormone was similar in the study groups. As reflected by decreased serum levels of osteocalcin (−43%; P < 0.001), bone formation was depressed in the patients. Serum cross-linked carboxyterminal telopeptide of human type I collagen (ICTP), a novel parameter of bone matrix degradation, was 9% higher in the patients (P = 0.03) than controls. The positive correlation between serum osteocalcin and ICTP in the controls (r = 0.59, P < 0.01) was absent in the patients (r = 0.05, P = 0.8). We conclude that in alcohol-intoxicated alcohol users, the parathyroid glands do not respond normally to a hypocalcemic stimulus, and that depressed bone formation is uncoupled from accelerated bone resorption.     

Alanine metabolism in skeletal muscle in tissue culture

Alanine production by skeletal muscle in tissue culture was studied using an established myogenic line (L₆) of rat skeletal muscle cells. Correlation analyses were performed on rates of metabolism of alanine, glucose, lactate and pyruvate over incubation periods up to 96 h. Alanine production did not correlate significantly with glucose utilization (r = 0.24, P < 0.20). Alanine production, however, did correlate with lactate production (r = 0.72, P < 0.0005) as well as medium (r = 0.50, P < 0.025) and intracellular (r = 0.85, P < 0.0005) pyruvate concentrations. The intercepts of the latter two correlation analyses indicated that when medium or cell pyruvate fell below 0.28 mM or 1 nmol/mg protein, respectively, net alanine consumption occurred. Alanine synthesis also correlated (r = 0.71, P < 0.0005) with the percent change in the cell mass action ratio for the sum of the alanine and aspartate aminotransferase reactions, i.e., [alanine] [malate]/[aspartate] [lactate]. These results suggest that alanine production is not necessarily linked to the rate of glucose utilization but rather to pyruvate overflow above a critical intracellular level; under conditions of pyruvate overflow, alanine synthesis is driven by the tendency to establish equilibrium between metabolites of the linked amino acid transaminases in skeletal muscle.     

Sister-chromatid exchanges in human lymphocytes treated with 4-chloromethylbiphenyl and benzyl chloride

At non-inhibitory concentrations, 4CMB and BC both induced small, but dose-related increases in SCE. The dose-response curves gave a highly significant correlation for 4CMB (r=0.996, P<0.001) and a significant correlation for BC (r=0.757, P<0.05) which reflects the relative activities of these substances in bacterial mutation tests.     

NUCLEOTYPIC EFFECT IN HOMEOTHERMS: BODY-MASS-CORRECTED BASAL METABOLIC RATE OF MAMMALS IS RELATED TO GENOME SIZE

The body-mass-corrected rate of basal metabolism in mammals is found to be negatively correlated with genome size, which is possibly linked to average cell size. The correlation, already significant at the species level (r_sp = –0.61, P < 0.0002), gradually strengthens as mean values for higher taxonomic levels (genera, families, and orders) are substituted in place of the species points (r_gen = –0.65, P < 0.0002; r_fam = –0.71, P < 0.0004; r_ord = –0.81, P < 0.008). This finding suggests that a sizeable part of the mammalian (above 25% of human) genome can be used for evolutionary adjustment of metabolic rate resulting from nucleotypic effect independently of body size. The total variance of mammalian genome-size values is found to be divided into two parts: within genera (43%) and taxonomic levels higher than order (57%), with no tangible variance being added between these taxonomic levels; whereas the body-mass-corrected rate of basal metabolism varies mainly at family (42%) and order (53%) levels. The only order for which there seems to be a necessary minimum of data for intraorder analysis (rodents) shows a not statistically significant correlation at the species level (r_sp = –0.47; P < 0.09), significant at the genus level (r_gen = –0.74; P < 0.04), and very high at the family level (r_fam = –0.98; P < 0.03). The concept of ultimate (distant) characters consolidation is proposed. In birds, with average genome sizes 40% of those of mammals, and similarly narrower ranges both of genome sizes and of body-mass-corrected metabolic rates, the correlation was not significant.     

Hand-held lactate analyzer as a tool for the real-time measurement of physical fatigue before slaughter and pork quality prediction

The objectives of this study were to assess the relationship between blood lactate variation measured at the plant, and pork quality variation on a large sample size and under commercial preslaughter handling conditions. A total of 600 pigs were randomly chosen on arrival at a commercial slaughter plant and blood samples taken from the ear vein at unloading (UN), after lairage (LA), in the restrainer (RE; before stunning) and at exsanguination (EX) were analysed for lactate content using a Lactate Scout Analyzer (LSA). In order to have a large range of measures, pigs were distributed into two groups; one kept in lairage overnight (G1) and the other for 2 to 3 h (G2) before slaughter. Meat quality was assessed in the Longissimus thoracis (LT), Semimembranosus (SM) and Adductor (AD) muscles by measuring the pH 30 min postmortem (pH1) and at 24 h postmortem (pHu), the colour and the drip loss. Blood lactate levels did not differ between G1 and G2 (P>0.05). A reduced muscle lactate and glucose contents (P=0.02 and P=0.004, respectively) resulting in a lower (P<0.001) glycolytic potential (GP) was observed in the LT muscle of G1 pigs when compared with G2 loins. In the LT muscle of G1 pigs, the lower GP resulted in an increased pHu (r=−0.67; P<0.001), decreased drip loss (r=0.57; P<0.001) and darker colour (r=0.50; P<0.001) compared with G2. In both G1 and G2 pigs, the lower GP was correlated to higher pHu value in the SM and AD muscles (r=−0.73; P<0.001). The greatest correlation was observed in G2 between blood lactate levels at LA and pHu value of the SM and AD muscles (r=0.46 and r=0.44, respectively; P<0.001 for both muscles). The second greatest correlation was found between blood lactate levels at EX and pH1 value in the SM muscle in both groups (r=−0.37 and r=−0.41, respectively; P<0.001 for both groups). Based on the results of this study, it appears that blood lactate levels, as measured by the LSA, reliably reflect the physiological response of pigs to perimortem stress and may help explain the variation in pork quality.     

Monitoring blood plasma leptin and lactogenic hormones in pregnant sows

The mechanism of action of leptin in pregnant breeding sows, in which hyperphagia is managed through dietary strategies, is yet to be clarified. The aim of this study was to monitor leptin concentrations and their interactions with lactogenic hormones in Large White×Landrace breeding multiparous sows (n=15). All sows showed a normal body condition (mean body condition score: 2.96). Blood samples were collected the day after weaning the litters, at insemination, every 15 days up to day 45 of pregnancy and every 7 days from day 46 to farrowing. At delivery, the placenta was collected for the analysis of leptin and leptin receptor expressions. Plasma leptin levels increased from the end of mid gestation (day 72) and remained high until farrowing (P<0.05). As expected, plasma prolactin (PRL), low during most of pregnancy, increased during the 2 weeks before farrowing (P<0.05), whereas progesterone levels reached plateau at 30 days of gestation and decreased at farrowing (P<0.05). Cortisol levels peaked close to farrowing (P<0.05). Leptin was expressed in the placenta, where the receptor expression analysis showed the presence of the short form but not of the long form. A positive correlation was found between leptin and PRL concentrations during mid (r=0.430; P<0.001) and late (r=0.687; P<0.001) pregnancy, and with progesterone in early pregnancy (r=0.462; P<0.05). During late gestation, a positive correlation was observed between leptin and cortisol (r=0.585; P<0.001). Our results suggested that, in restrictively fed pregnant sows, the leptin levels increased from the end of mid pregnancy to delivery, confirming the presence of leptin resistance. We showed a correlation between leptin and lactogenic hormones during different stages of pregnancy in sows. Lactogenic hormones show pregnancy-specific changes in their secretion and all may become involved in modulating leptin signal.     

Furosemide-sensitive Na+ and K+ transport and human erythrocyte volume

The relationship between cation transport and cell volume in human erythrocytes was investigated by measuring ouabain-sensitive K⁺ influx, ouabain-resistant, furosemide-sensitive K⁺ influx, and ouabain + furosemide-resistant K⁺ influx, and maximal ouabain binding in microcytic, normocytic and macrocytic red cells. A significant correlation was found between the mean corpuscular volume and furosemide-sensitive K⁺ influx normalized either to cell number (r = 0.636, P < 0.001) or to cell volume (r = 0.488, P < 0.001). No relationship was seen between mean corpuscular volume and ouabain-sensitive K⁺ influx, and the number of ouabain-binding sites per cell was only weakly correlated with mean corpuscular volume (r = 0.337, P < 0.05). A slight, negative relationship existed between mean corpuscular volume and ouabain + furosemide-resistant K⁺ influx expressed per volume of cells (r = −0.359, P < 0.01), and an apparent relationship between furosemide-sensitive K⁺ influx and mean corpuscular hemoglobin concentration (r = 0.446, P < 0.01) disappeared when microcytic samples were excluded from analysis. Furosemide-sensitive transport, including Na⁺ influx and K⁺ and Na⁺ efflux, was completely absent in microcytic cells from one patient with α-thalassemia minor. In addition, these cells exhibited a furosemide-resistant, Cl⁻-dependent K⁺ influx. Exposure of normal erythrocytes to hypotonic conditions (196 mosM) increased furosemide-sensitive K⁺ influx by a mean of 45% (P < 0.05), while exposure to hypertonic conditions (386 mosM) had no significant effect. The results indicate that furosemide-sensitive transport and cell volume are interrelated in human erythrocytes. However, the inability to fully recreate this relationship with in vitro manipulation of cell volume suggests that this relationship is established prior to red cell maturation.     

Assessment of bone remodeling using biochemical indicators of type I collagen synthesis and degradation: relation to calcium kinetics

In this study, we investigated the relation between calcium kinetic indices of bone remodeling (resorption rate, r; and formation rate, m, respectively) and two serum markers of type I collagen turnover: the pyridinoline cross-linked carboxyterminal telopeptide domains of type I collagen (S-ICTP a marker of bone matrix degradation) and the carboxyterminal propeptide of human type I procollagen (S-PICP, a marker of bone matrix formation). We studied three groups: (i) healthy controls (n = 19), (ii) a mixed group of high and low-turnover bone diseases without mineralization defects (myxedema, thyrotoxicosis and primary hyperparathyroidism n = 38), and (iii) osteoporosis (n = 52). In healthy controls, a significant regression of S-PICP on m was obtained (R = 0.53, SEE/Y = 0.44, P < 0.02). Significant regressions were also demonstrable in high- and low-turnover bone disease (R = 0.50, P < 0.001), SEE/Y = 61%) and osteoporosis (R = 0.49, P < 0.001, SEE/Y = 50%). In controls the regression coefficient for the regression of S-ICTP on r was 0.19 (NS), in high and low turnover bone disease 0.66, (SEE/Y = 59%, P < 0.001) and in the osteoporotic group 0.40 (SEE/Y = 61%, P < 0.01). We conclude that S-PICP and S-ICTP reflect whole skeletal bone formation and resorption rates in a variety of metabolic bone diseases including osteoporosis.     

Nitrogen partitioning and isotopic discrimination are affected by age and dietary protein content in growing lambs

It is difficult to separate an age-dependent fall in nitrogen use efficiency (NUE; N balance/N intake) in growing ruminants from a progressively decrease in animal protein requirements over time. This study examined the effect of dietary protein content on N partitioning, digestibility and N isotopic discrimination between the animal and its diet (Δ¹⁵N_animal-diet) evaluated at two different fattening periods (early v. late). Twenty-four male Romane lambs (age: 19 ± 4.0 days; BW: 8.3 ± 1.39 kg) were equally allocated to three dietary CP treatments (15%, 17% and 20% CP on a DM basis). Lambs were reared with their mothers until weaning, thereafter housed in individual pens until slaughter (45 kg BW). During the post-weaning period, lambs were allocated twice (early fattening (30 days post-weaning) and late fattening (60 days post-weaning)) to metabolic cages for digestibility and N balance study. When diet CP content increased, the average daily gain of lambs increased (P < 0.05) while the age at slaughter decreased (P = 0.01), but no effect was observed on feed efficiency (P > 0.10). Diet CP content had limited effect on lamb carcass traits. Higher fibre digestibility was observed at the early v. late fattening period (P < 0.001). The N intake and the urinary N excretion increased when diet CP content increased (P < 0.001) and when shifting from early to late fattening period (P < 0.001). Faecal N excretion (P = 0.14) and N balance (P > 0.10) were not affected by diet CP content. Nitrogen digestibility increased (P < 0.001) as the diet CP content increased and on average it was greater at late v. early fattening period (P = 0.02). The NUE decreased (P = 0.001) as the diet CP content increased and as the lamb became older (P < 0.001). However, the age-dependent fall in NUE observed was lower at high v. low dietary CP content (CP × age interaction; P = 0.04). The Δ¹⁵N_animal-diet was positively correlated (P < 0.05) with N intake (r = 0.59), excretion of faecal N (r = 0.41), urinary N (r = 0.69) and total manure N (r = 0.64), while negatively correlated with NUE (r = −0.57). Overall, the experiment showed NUE was lower in older lambs and when lambs were fed high diet CP content, and that Δ¹⁵N_animal-diet was a useful indicator not only for NUE but also for urinary N excretion, which is a major environmental pollution factor on farm.     

Circulating microparticles in patients with coronary heart disease and its correlation with interleukin-6 and C-reactive protein

Microparticles (MPs) are vesicles released from activated or apoptotic cells. MP derive from various cells, most notably platelets, but also leucocytes, lymphocytes, erythrocytes, and endothelial cells. The aim of this study was to investigate endothelial MP (EMP), platelet MP (PMP), lymphocyte MP and monocyte MP and TF-positive MPs (TF⁺ MPs) in patients with coronary heart disease (CHD), and to evaluate the correlation of these MPs with Interleukin-6 (IL-6) and C-reactive protein (CRP). Different cell-derived MPs and TF⁺ MPs were analyzed by flow cytometry in 40 patients with myocardial infarction (MI), 30 unstable angina (UA), 20 stable angina (SA) and 20 healthy individuals, and IL-6 and CRP were determined by ELISA and special protein analyzer, respectively. Compared with SA and control, EMP and PMP was significantly elevated in MI and UA (P < 0.001), and TF⁺ MPs was significantly elevated in MI and UA (P < 0.001). EMP and PMP correlated with IL-6 (r = 0.822, P < 0.001 and r = 0.567, P < 0.001; respectively) or CRP level (r = 0.597, P < 0.001 and r = 0.66, P < 0.001; respectively). Different cell-derived MPs in CHD may indicate the different pathophysiological changes in vessels, and MPs may both participate in the development of thrombosis and enhance the vascular inflammation.     

Plasma metabolic profile in COPD patients: effects of exercise and endurance training

The study examines plasma metabolic profiles of patients with chronic obstructive pulmonary disease (COPD) to prove whether the disease influences metabolism at rest and after endurance training. This is based on the hypothesis that metabolome levels should reflect impaired skeletal muscle bioenergetics in COPD. The study aims to test this hypothesis by evaluating plasma metabolic profiles in COPD patients before and after 8?weeks of endurance exercise training. We studied blood samples from 18 COPD patients and 12 healthy subjects. Pre- and post-training blood plasma samples at rest and after constant-work rate exercise (CWRE) at 70% of pre-training Watts peak were analyzed by ¹H-nuclear magnetic resonance spectroscopy to assess metabolite profiles. The two groups presented training-induced physiological changes in the VO₂ peak and in blood lactate levels (P?<?0.01 each). Before training, the two groups also showed differences in metabolic profiles at rest (P?<?0.05). Levels of valine (r?=?0.51, P?<?0.01), alanine (r?=?0.45, P?<?0.05) and isoleucine (r?=?0.51, P?<?0.01) were positively associated with body composition (Fat Free Mass Index). While training showed a significant impact on the metabolic profile in healthy subjects (P?<?0.001), with changes in levels of amino acids, creatine, succinate, pyruvate, glucose and lactate (P?<?0.05 each), no equivalent training-induced effects were seen in COPD patients in whom only lactate decreased (P?<?0.05). This study shows that plasma metabolic profiling contributes to the phenotypic characterization of COPD patients.     

Plasma total antioxidant capacity is associated with dietary intake and plasma level of antioxidants in postmenopausal women

Increased plasma total antioxidant capacity (TAC) has been associated with a high consumption of fruits and vegetables. However, limited information is available on whether plasma TAC reflects the dietary intake of antioxidants and the levels of individual antioxidants in plasma. By using three different assays, the study aimed to determine if plasma TAC can effectively predict dietary intake of antioxidants and plasma antioxidant status. Forty overweight and apparently healthy postmenopausal women were recruited. Seven-day food records and 12-h fasting blood samples were collected for dietary and plasma antioxidant assessments. Plasma TAC was determined by vitamin C equivalent antioxidant capacity (VCEAC), ferric-reducing ability of plasma (FRAP) and oxygen radical absorbance capacity (ORAC) assays. TAC values determined by VCEAC were highly correlated with FRAP (r=0.79, P<.01) and moderately correlated with ORAC (r=0.34, P<.05). Pearson correlation analyses showed that plasma TAC values by VCEAC and ORAC had positive correlation with plasma uric acid (r=0.56 for VCEAC; r=0.49 for ORAC) and total phenolics (r=0.63 for VCEAC; r=0.36 for ORAC). However, TAC measured by FRAP was correlated only with uric acid (r=0.69). After multivariate adjustment, plasma TAC determined by VCEAC was positively associated with dietary intakes of γ-tocopherol (P<.001), β-carotene (P<.05), anthocyanidins (P<.05), flavones (P<.05), proanthocyanidins (P<.01) and TAC (P<.05), as well as with plasma total phenolics (P<.05), α-tocopherol (P<.001), β-cryptoxanthin (P<.05) and uric acid (P<.05). The findings indicate that plasma TAC measured by VCEAC reflects both dietary and plasma antioxidants and represents more closely the plasma antioxidant levels than ORAC and FRAP.