The Effect of Gestational Age and Labour on Markers of Lipid and Protein Oxidation in Cord Plasma

There are many potential sources of reactive oxidants around the time of birth and pre-term infants are considered to be particularly vulnerable to oxidative injury. To gain insight into these processes, we have measured biomarkers of lipid and protein oxidation in umbilical cord plasma and related concentrations to mode of delivery and gestational age. Protein carbonyls were measured by ELISA and malondialdehyde (MDA) by HPLC after reaction with thiobarbituric acid, for 54 pre-term (≤36 weeks gestational age) and 43 term infants. Protein carbonyls were significantly lower in pre-term (median for <32 weeks gestational age 0.048?nmol/mg protein) than in term infants (0.105?nmol/mg, p=0.004), and were unrelated to mode of delivery. In contrast, MDA concentrations were higher in the very pre-term (<32 weeks gestation) group (2.47 compared with 1.83?μM for term infants, p<0.0001). MDA concentrations were higher in infants who were born with labour compared with elective caesarean section. Pre-eclampsia in the mother was associated with higher cord blood MDA concentrations. The MDA results are consistent with other studies of this marker and could be interpreted as indicating increased oxidative stress associated with prematurity and labour. However, the lower protein carbonyls in pre-term infants would lead to an opposite interpretation. More information is needed on the source and fate of these and other biomarkers before drawing strong conclusions on how they reflect oxidative stress in this and other clinical situations.     

Correlation between lactoferrin and beneficial microbiota in breast milk and infant’s feces

Lactoferrin (LF) is a natural component of human milk with antimicrobial, immunostimulatory and immunomodulatory properties. Several in vitro studies suggest that LF could promote an environment in the gut of neonates that favors colonization with beneficial bacteria. However, clinical studies on the correlation between the concentration of LF in breast milk and feces of infants and the gut microbiota in infants are lacking. In our study we analyzed the content of LF and the microbiota of breast milk and feces of infants of 48 mother–infant pairs (34 full-term and 14 pre-term infants) at birth and 30 days after delivery. In the term group, a significant decrease of mean LF concentration between colostrum (7.0 ± 5.1 mg/ml) and mature milk (2.3 ± 0.4 mg/ml) was observed. In pre-term group, breast milk LF levels were similar to those observed in full-term group. Fecal LF concentration of healthy infants was extremely high both in term and pre-term infants, higher than the amount reported in healthy children and adults. In term infants mean fecal LF levels significantly increased from birth (994 ± 1,828 μg/ml) to 1 month of age (3,052 ± 4,323 μg/ml). The amount of LF in the feces of 30 day-old term infants was significantly associated with maternal mature milk LF concentration (p = 0.030) confirming that breast milk represents the main source of LF found in the gut of infants. A linear positive correlation between colostrum and mature milk LF concentration was observed (p = 0.008) indicating that milk LF levels reflect individual characteristics. In pre-term infants higher mean concentrations of fecal LF at birth (1,631 ± 2,206 μg/ml) and 30 days after delivery (7,633 ± 9,960 μg/ml) were observed in comparison to full-term infants. The amount of fecal bifidobacteria and lactobacilli resulted associated with the concentration of fecal LF 3 days after delivery (p = 0.017 and p = 0.026, respectively). These results suggest that high levels of fecal LF in neonates, particularly in the first days of life, could represent an important factor in the initiation, development and/or composition of the neonatal gut microbiota. Since early host–microbe interaction is a crucial component of healthy immune and metabolic programming, high levels of fecal LF in neonates may beneficially contribute to the immunologic maturation and well-being of the newborn, especially in pre-term infants.     

The effect of gestational age and labour on markers of lipid and protein oxidation in cord plasma

There are many potential sources of reactive oxidants around the time of birth and pre-term infants are considered to be particularly vulnerable to oxidative injury. To gain insight into these processes, we have measured biomarkers of lipid and protein oxidation in umbilical cord plasma and related concentrations to mode of delivery and gestational age. Protein carbonyls were measured by ELISA and malondialdehyde (MDA) by HPLC after reaction with thiobarbituric acid, for 54 pre-term (< or = 36 weeks gestational age) and 43 term infants. Protein carbonyls were significantly lower in pre-term (median for < 32 weeks gestational age 0.048nmol/mg protein) than in term infants (0.105 nmol/mg, p = 0.004), and were unrelated to mode of delivery. In contrast, MDA concentrations were higher in the very pre-term (<32 weeks gestation) group (2.47 compared with 1.83 microM for term infants, p < 0.0001). MDA concentrations were higher in infants who were born with labour compared with elective caesarean section. Pre-eclampsia in the mother was associated with higher cord blood MDA concentrations. The MDA results are consistent with other studies of this marker and could be interpreted as indicating increased oxidative stress associated with prematurity and labour. However, the lower protein carbonyls in pre-term infants would lead to an opposite interpretation. More information is needed on the source and fate of these and other biomarkers before drawing strong conclusions on how they reflect oxidative stress in this and other clinical situations.     

Hormonal changes during the perinatal period: Serum testosterone,some of its precursors,and FSH and prolactin in preterm and fullterm male infant cord blood and during the first week of life

To investigate fetal regulation of the endocrine testis during the third trimester of gestation, pregnenolone, progesterone, 17-hydroxyprogesterone, androstenedione, testosterone, FSH and prolactin concentrations were measured in the umbilical circulation of 31–35 preterm (27–37 weeks) and 18–19 fullterm (39–42 weeks) male infants, and postnatally until 5 days of age in 27–39 fullterm male infants. 17-hydroxyprogesterone and prolactin concentrations increased significantly (P < 0.001) between 27–37 weeks of gestation; the other hormones measured were unchanged. The levels of progesterone in preterm infants, and prenenolone, progesterone and 17-hydroxyprogesterone in the cord vein of fullterm infants were significantly (P < 0.001–0.05) higher than those in the cord artery. Androstenedione concentrations were similar in the cord artery and vein, and decreased less than pregnenolone, progesterone and 17-hydroxyprogesterone after birth, reflecting major androstenedione production in the fetus. Testosterone concentrations were higher (P < 0.01–0.05) in the cord artery than in the vein, both in preterm and fullterm infants, showing the main site of testosterone production to be the fetal compartment. Postnatally, testosterone increased clearly from concentrations of 0.25 ± 0.05 (SE) mg/ml in the cord artery and 0.10 ± 0.01 in the cord vein to 0.94 ± 0.14 ng/ml in the peripheral vein on the first postnatal day, and decreased thereafter clearly between 3–5 days. FSH did not change during the first 5 postnatal days. Concentrations of all the other hormones measured decreased significnatly after birth.It is concluded from the cord blood hormone levels of infants born between 27–42 weeks of gestation that: (1) The third trimester of gestation represents a stable phase of endocrine development with relatively small changes in circulating hormone levels; (2) Both the placenta and the fetus seem to be able to produce androstenedione in the perinatal period; and (3) The initial increase in testosterone after birth is indicative of the inhibitory effect of placental steriods on testicular endocrine function during the last trimester of gestation.     

Ubiquinone-10 plasma concentrations in healthy European children

The reduced form of ubiquinone-10 (coenzyme Q) has been shown to represent an important physiologic antioxidant principle in human blood. In order to establish a reference range for infants, we measured plasma levels of ubiquinone in 50 healthy European children aged 2 months to 15 years. A mean ±SD) value of 0.75±0.27 μg/ml plasma (0.87±0.31 μM) was determined; ubiquinone concentrations were not found to be sex-dependent (0.7±0.24μg/ml for girls, n=17, and 0.7±0.28μg/ml for boys, n=33) but correlated negatively with age (r = -0.37, P=0.0075). This negative correlation was mainly due to relatively high levels in infants approximately 1 year old.

The mean value determined does not significantly differ from the average ubiquinone plasma concentrations determined in healthy Nigerian children (0.85±0.40 μg/ml, n= 18) in a previous study (Becker K, Boetticher D, Leichsenring M. Internat J Vitam Nutr Res 1995, in press).     

Coenzyme Q concentration and total antioxidant capacity of human milk at different stages of lactation in mothers of preterm and full-term infants

Coenzyme Q₁₀(CoQ₁₀) in human milk at different stages of maturity in mothers of preterm and full-term infants and its relation to the total antioxidant capacity of milk is described for the first time. Thirty healthy breastfeeding women provided colostrum, transition-milk and mature-milk samples. Coenzyme Q, α-, γ- and δ-tocopherol, fatty acids and the total antioxidant capacity of the milk were analyzed. Coenzyme Q₁₀ was found at higher concentrations for colostrum (0.81 ± 0.06 vs. 0.50 ± 0.05 μmol/l) and transition milk (0.75 ± 0.06 vs. 0.45 ± 0.05 μmol/l) in the full-term vs. the preterm group (similar results were found for total antioxidant capacity). Concentrations of α- and γ-tocopherol were higher in the full-term group and decreased with time. In conclusion, CoQ₁₀ is present in breast milk, with higher concentration in mothers of full-term infants. CoQ₁₀ in breast milk decreases through lactation in mothers delivering full-term infants. Also, CoQ₁₀, α- and γ-tocopherol concentration in human milk directly correlates with the antioxidant capacity of the milk.     

Chromium status of full-term and preterm newborns

In order to obtain reference values from normal babies, Cr status of full-term newborns has been studied. Plasma and urine values were (mean±SEM) 0.7±0.1 μg/L and 0.9±0.3 μg/L, respectively, for the first month of life (n=19), and 0.6±0.1 μg/L and 0.8±0.2 μg/L for the second-to-third-month period (n=31). Premature newborns (gestational age 28–36 wk) were compared to these control values; concentrations were 0.9±0.1 μg/L and 1.1±0.2 μg/L for the first month (n=47), and 1.0±0.2 μg/L and 1.5±0.3 μg/L for the second to third months (n=27). For the whole group, there was a positive correlation between plasma and urine concentrations (p=0.0001); multiple regression analysis was performed between plasma levels and gestational age at birth (p=?0.002) and postnatal age (NS). Plasma levels of prematures and full terms were statistically different (p=0.03) only for the second- to third-month period. It is suggested that these high Cr levels result from high dietary intakes and/or high absorption rates.     

Effects of Metformin and Vanadium on Leptin Secretion from Cultured Rat Adipocytes

Objective: We have reported that glucose utilization regulates leptin expression and secretion from isolated rat adipocytes. In this study, we employed two antidiabetic agents that act to increase glucose uptake by peripheral tissues, metformin and vanadium, as pharmacological tools to examine the effects of altering glucose utilization on leptin secretion in primary cultures of rat adipocytes. Research Methods and Procedures: Isolated adipocytes (100 μL of packed cells per well) were anchored in a defined matrix of basement membrane components (Matrigel) with media containing 5.5 mM glucose and incubated for 96 hours with metformin or vanadium. Leptin secretion, glucose utilization, and lactate production were assessed. Results: Metformin (0.5 and 1.0 mM) increased glucose uptake in the presence of 0.16 nM insulin by 37 ± 10% (p < 0.005) and 62 ± 8% (p < 0.0001) over insulin alone, respectively. Metformin from 0.5 to 5.0 mM increased lactate production by 105 ± 43% (p < 0.025) to 202 ± 52% (p < 0.0025) and at 1.0 and 5.0 mM increased the proportional rate of glucose conversion to lactate by 78 ± 18% (p < 0.005) and 166 ± 41% (p < 0.0025), respectively. At concentrations less than 0.5 mM, metformin did not affect leptin secretion, but at 0.5 mM, the only concentration that significantly increased glucose utilization without increasing glucose conversion to lactate, leptin secretion was modestly stimulated (by 20 ± 9%; p < 0.05). Concentrations from 1.0 to 25 mM inhibited leptin secretion by 25 ± 8% (p < 0.005) to 89 ± 4% (p < 0.0001). Across metformin doses, leptin secretion was inversely related to the percentage of glucose taken up and released as lactate (r = ?0.74; p < 0.0001). Vanadium (5 to 20 μM) increased glucose uptake from 20 ± 7% (p < 0.01) to 34 ± 13% (p < 0.02) and increased lactate production at 5 μM by 17 ± 8% (p < 0.025) and 10 μM by 61 ± 20% (p < 0.02) but did not alter the conversion of glucose to lactate. Vanadium (5 to 50 μM) inhibited leptin secretion by 33 ± 6% (p < 0.0025) to 61 ± 8% (p < 0.0001). Discussion: Both metformin and vanadium increase glucose uptake and inhibit leptin secretion from cultured adipocytes. The inhibition of leptin secretion by metformin is related to an increase in the metabolism of glucose to lactate. The inhibition by vanadium most likely involves direct effects on cellular phosphatases. We hypothesize that the effect of glucose utilization to stimulate leptin production involves the metabolism of glucose to a fate other than anaerobic lactate production, possibly oxidation or lipogenesis.     

Oral a-tocopherol Supplementation Inhibits Lipid Oxidation in Established Human Atherosclerotic Lesions

Background: Much experimental evidence suggests that lipid oxidation is important in atherogenesis and in epidemiological studies dietary antioxidants appear protective against cardiovascular events. However, most large clinical trials failed to demonstrate benefit of oral antioxidant vitamin supplementation in high-risk subjects. This paradox questions whether ingestion of antioxidant vitamins significantly affects lipid oxidation within established atherosclerotic lesions. Methods and results: This placebo-controlled, double blind study of 104 carotid endarterectomy patients determined the effects of short-term α-tocopherol supplementation (500 IU/day) on lipid oxidation in plasma and advanced atherosclerotic lesions. In the 53 patients who received α-tocopherol there was a significant increase in plasma α-tocopherol concentrations (from 32.66±13.11 at baseline to 38.31±13.87 (mean±SD) μmol/l, p&lt;0.01), a 40% increase (compared with placebo patients) in circulating LDL-associated α-tocopherol (p&lt;0.0001), and their LDL was less susceptible to ex vivo oxidation than that of the placebo group (lag phase 115.3±28.2 and 104.4±15.7 min respectively, p&lt;0.02). Although the mean cholesterol-standardised α-tocopherol concentration within lesions did not increase, α-tocopherol concentrations in lesions correlated significantly with those in plasma, suggesting that plasma α-tocopherol levels can influence lesion levels. There was a significant inverse correlation in lesions between cholesterol-standardised levels of α-tocopherol and 7β-hydroxycholesterol, a free radical oxidation product of cholesterol. Conclusions: These results suggest that within plasma and lesions α-tocopherol can act as an antioxidant. They may also explain why studies using &lt;500 IU α-tocopherol/day failed to demonstrate benefit of antioxidant therapy. Better understanding of the pharmacodynamics of oral antioxidants is required to guide future clinical trials.     

Influence of acoustic stimulation on the circadian and ultradian rhythm of premature infants

The aim of the present study was to evaluate the development of the circadian rhythm of the salivary cortisol in premature infants and its correlation with the onset of the sleep–activity behavior pattern during the first 3 weeks of life under controlled light:dark conditions. Furthermore, we investigated the influence of acoustic stimulation by audiotaped lullabies or the maternal voice on the cortisol values and long-term sleep–activity patterns. The study was a block-randomized, prospective clinical trial with a study population of 62 preterm neonates (30?<?37 gestational age). We compared two study groups who listened either to music or to the maternal voice (music: N?=?20; maternal voice: N?=?20) with a matched control group (N?=?22). The acoustic stimulation took place every evening between 20:00 and 21:00?h for 30?min over a period of 2 weeks. The cortisol values and activity–rest behavior of the neonates were determined during the first 3 weeks of life on the 1st, 7th and 14th day. Actigraphic monitoring was used to record the activity pattern continuously over 24?h and a validated algorithm for neonates was used to estimate sleep and wakefulness. The saliva samples were obtained 10?min before and 10?min after the acoustic interventions for the study groups. Additionally, saliva samples were obtained from the control group seven times over a 24-h period (20:00, 21:00, 01:00, 05:00, 08:00, 13:00 and 17:00?h). The cortisol data were analyzed by fast Fourier transformation to assess periodic characteristics and frequencies. Hierarchical linear modeling was further performed for the statistical analysis. Results: The cortisol rhythm analysis indicated a circadian rhythm pattern for only one premature infant, all others of the neonates showed no circadian or ultradian rhythm in cortisol. Cortisol level of the premature neonates was significantly higher during the first day of the study period at night-time (median: 17.1?nmol/L, IQR?=?9.7–24.4?nmol/L) than on days 7 (median: 9.6?nmol/L, IQR?=?4.7–14.6?nmol/L; Tukey-HSD, z?=?4.12, p?<?0.001) and 14 (IQR?=?5.8–13.7?nmol/L; Tukey-HSD, z?=?2.89, p?<?0.05). No significant effect of acoustic stimulation was observed on the cortisol concentration and sleep–wake behavior. The activity–sleep rhythm of preterm neonates was dominated by ultradian rhythm patterns with a prominent period length of 4?h (30.5%). Activity frequencies of neonates were also significantly higher overnight on the first study day (mean: 329?±?185.1?U) than of night seven (mean: 260.2?±?132.4?U; Tukey-HSD, z?=?2.50, p?<?0.05). Quiet-activity patterns increased, whereas high-activity patterns decreased during the observation period. Average sleep time increased significantly during the study time from day 1 to day 7 (Tukey-HSD, z?=?2.51, p?<?0.05). In conclusion, premature infants showed higher cortisol levels – without a circadian rhythmicity – and higher activity frequencies in the first days after birth which may reflect an adaptation process of neonates after birth. Cortisol concentrations and the activity patterns were not influenced by music interventions.     

Vitamin D in Overweight/Obese Women and Its Relationship With Dietetic and Anthropometric Variables

Overweight/obese persons usually have an inadequate vitamin D status, a situation commonly made worse by an inadequate intake of this vitamin. For this reason, the aim of this study was to analyze dietetic and anthropometric differences in a group of young, overweight/obese Spanish women with respect to their vitamin D status. The study subjects were 66 white Spanish women (aged 20–35 years) with a BMI of 24–35 kg/m². Dietetic, anthropometric, and biochemical data were collected. Women were divided into two groups depending on their serum vitamin D concentrations: LD (women with <90 nmol/l 25(OH)D) and HD (women with ≥90 nmol/l 25(OH)D). The intakes of vitamin D, calcium, and supplements were similar in both groups. The body weight, BMI, and waist circumference of the HD subjects were smaller than those recorded for the LD subjects (68.6 ± 4.2 kg, 26.0 ± 1.3 kg/m², and 79.4 ± 3.4 cm compared to 76.2 ± 9.8, 28.6 ± 3.2 kg/m², and 86.2 ± 9.3 cm, respectively; P < 0.05). The hip circumference and the waist/hip ratio were similar in both groups. A BMI of <27.7 kg/m² (P50) was associated with serum vitamin D concentrations of ≥90 nmol/l (odds ratio = 0.1313; confidence interval: 0.0149–1.1599; P < 0.05). Overweight/obese women are at higher risk of vitamin D deficiency, largely due to excess adiposity rather than inadequate intake.     

Intestinal microbiota in exclusively breast-fed infants with blood-streaked stools

Intestinal microbiota in exclusively breast-fed infants with blood-streaked stools and in healthy exclusively breast-fed babies was compared. Total anaerobes, bifidobacteria, lactobacilli, coliform bacteria, enterococci and clostridia were quantified by cultivation methods in feces of 17 full-term exclusively breastfed patients (aged 16.3 ± 7.4 weeks) with blood-streaked stools and in the control group of 22 healthy fullterm exclusively breast-fed infants (13.7 ± 6.4 weeks). Specific fluorescence in situ hybridization kits for Bifidobacterium spp. were used for the quantitative detection of bifidobacteria in samples. Control samples had significantly (p < 0.05) higher counts of total anaerobes. Bifidobacteria were not detected in patients’ samples in 65 % and in controls in 36 % (p < 0.01). Bifidobacteria counts were also significantly higher in the control group (p < 0.01). Furthermore, clostridia strains were detected only in feces from bifidobacteria-negative infants reaching counts >8 log CFU/g. Lactobacilli were not detected in 65 % patients and in 45 % control samples. However, this difference was not significant as well as the difference in lactobacilli counts. Eosinophilia was observed in 35 % of patients, low IgA concentration in 71 % and also low IgG concentration in 71 %. pANCA positivity was found in 53 % of patients. In conclusion a significant low proportion of bifidobacterial microbiota in patients with blood-streaked stools was shown in comparison with controls.     

Application of flow cytometry for estimation of lipid content changes induced by arachidonic acid and methyl-β-cyclodextrin in the lipid bodies of epithelial cells

Lipid bodies (LB) are dynamic inducible organelles with the key roles in cellular lipid metabolism, intracellular trafficking and signaling. These structures have a neutral lipid-rich core which contains mainly triacylglycerides (TAG) and cholesterol esters (CE). With the use of flow cytometry and lipophylic fluorescent dye Nile red (NR) we studied LB biogenesis in nonfixed freshly isolated epithelial cells derived from the frog (Rana temporaria L.) urinary bladder. These cells are characterized by numerous small LB located diffusely in the cytoplasm. To target neutral lipids in LB, we used arachidonic acid (AA), an inducer of LB biogenesis in different cell types, and methyl-β-cyclodextrin (MβCD), non-permeable cholesterol acceptor, widely used to extract cholesterol from the lipid rafts. The cells were incubated with 10–50 μM AA for 1 h or with 400–2000 μM MβCD for 30 min; after that they were stained with NR, and fluorescence was measured by flow cytometer at λ_ex = 488 nm and λ_em = 575 ± 15 nm. In parallel, side scatter (SS) was analyzed. It was found that AA in a dose-dependent manner increased NR fluorescence. At a maximal concentration used, AA increased NR fluorescence and SS by 41 ± 2% and by 15 ± 3% (p < 0.001), respectively. Analysis of lipid composition of cell extracts revealed a significant increase of TAG by 10 μM AA. MβCD starting from 400 μM decreased dose-dependently the NR fluorescence and SS. Its effect was accompanied by a decrease of cellular free cholesterol by 6% (p < 0.01) and cholesterol ester by 21% (p < 0.001). This fact indicates mobilization of cholesterol from cholesterol esters stored in LB in order to restore cholesterol level in the plasma membrane. Taken together, our data demonstrate that flow cytometry in combination with NR staining represents a reliable tool to be used for recording of changes in different neutral lipids class content within LB in living cells non-specialized on the fat storage.     

Sequential Evaluation of Plasma Retinol-Binding Protein Response to Vitamin A Administration in Very-Low-Birth-Weight Neonates

Vitamin A (retinol) deficiency is associated with impaired healing from lung injury in very-low-birth-weight (VLBW) neonates susceptible to bronchopulmonary dysplasia (BPD). Vitamin A supplementation from birth may ameliorate this adverse outcome. We hypothesized that plasma retinol-binding protein (REP) response to vitamin A administration, which provides a dynamic measure of vitamin A status, might be useful for early recognition of vitamin A deficiency in VLBW neonates at risk for BPD. We prospectively studied 20 VLBW neonates (inclusion criteria: birth weight <1300 g, gestational age <30 weeks, need for supplemental oxygen and mechanical ventilation for >24 h after birth) who were eligible to receive vitamin A supplementation. In addition to sequential assessment of vitamin A status, we measured plasma RBP just before and 3 and 6 h after an intramuscular injection of vitamin A (2000 IU/kg retinyl palmitate) on Postnatal Days 1, 7, 15, 21, 29, and 43. The percentage increase in plasma RBP (Δ-RBP) was calculated. A high plasma Δ-RBP value (>8%) is indicative of vitamin A deficiency. Based on pulmonary outcome, the infants were divided into two groups: BPD (n = 12) and No BPD (n = 8). Mean vitamin A intake ranged from 1414 to 2114 IU/kg/day and did not differ between infant groups. Mean plasma vitamin A concentration increased from baseline levels on Postnatal Day 1 to levels within the desired range of 1.05-2.10 μmol/liter (30.0-60.0 μg/dl) during supplementation period in both infant groups. Infants with BPD, in contrast to those without BPD, had worsening plasma Δ-RBP values from Postnatal Day 15, indicative of persistence of vitamin A deficiency despite supplementation and normalization of plasma vitamin A concentration. We conclude that plasma RBP response to vitamin A administration is useful for early recognition of vitamin A deficiency in VLBW neonates at risk for BPD.     

Methionine,folic acid and vitamin B12 in growing-finishing pigs: Impact on growth performance and meat quality

Growth performance, metabolic variables, and meat quality were measured in 78 growing-finishing pigs using supplements of 0 (C), or 0.2% of DL-methionine (M), and three combinations of folic acid [mg/kg] and cyanocobalamin [μg/kg], respectively 0 and 0 (V0), 10 and 25 (V1), and 10 and 150 (V2) in a 2 × 3 factorial arrangement. Feed conversion was lower (p = 0.05) in M than in C pigs during the growing period (0–4 weeks). Both V1 and V2 treatments increased plasma vitamin B₁₂ (p < 0.01) and decreased plasma homocysteine (p < 0.01). Plasma 5-methyl-tetrahydrofolates were the lowest, highest and intermediate in V0, V1 and V2 pigs (p < 0.04), respectively. In V2 meat, folates were 32% higher, vitamin B₁₂, 55% higher and homocysteine, 28% lower than in V0 (p < 0.01). Oxidative stability of the fresh meat was similar among treatments during a storage period of 42 days. Therefore, methionine supplements improved growth performance during the growing period. Vitamin supplements interacted with the methionine cycle pathway, increased vitamin content of pork meat but did not improve oxidative stability of the fresh meat during storage.     

Survival,Birth Characteristics,and Cause-Specific Mortality of White-Tailed Deer Neonates

ABSTRACT Understanding survival of and factors that may predispose newborn deer (Odocoileus spp.) to mortality contribute to improved understanding of population dynamics. We captured free-ranging white-tailed deer neonates (n = 66) of radiocollared females that survived severe (Winter Severity Index [WSI] = 153) and mild (WSI = 45) winters 2000–2001 and 2001–2002. Mean dates of birth (26 May ± 1.7 [SE] days and 26 May ± 1.3 days) and estimated birth-masses of 2.8 ± 0.1 kg and 3.0 ± 0.1 kg were similar between springs 2001 (n = 31) and 2002 (n = 35), respectively. Neonate survival was similar between years; pooled mortality rates of neonates were 0.14, 0.11, and 0.20 at 0–1 weeks, 2–4 weeks, and 5–12 weeks of age, respectively, and overall survival rate for neonates to 12 weeks of age was 0.47. Predation accounted for 86% of mortality; the remaining 14% of deaths were attributed to unknown causes. Black bears (Ursus americanus) were responsible for 57% and 38% of predation of neonates in springs 2001 and 2002, respectively, whereas bobcats (Felis rufus) accounted for 50% in 2002. Wolves (Canis lupus) accounted for only 5% of predator-related deaths. Low birth-mass, smaller body size, and elevated concentrations of serum urea nitrogen (26.1 ± 2.6 mg/dL vs 19.3 ± 0.8 mg/dL) and tumor necrosis factor-α (82.6 ± 78.6 pg/mL vs. 2.3 ± 0.5 pg/mL) were associated with neonates that died within 1 week of birth. Even though we did not detect a direct relation between winter severity and birth or blood characteristics of neonates, evidence suggests that birth-mass and key serum indices of neonate nutrition were associated with their early mortality. Thus, managers can make more informed predictions regarding survival and cause-specific mortality of fawns and adjust management strategies to better control deer population goals.     

Plasma tocopherol,retinol, and carotenoid concentrations in free-ranging Humboldt penguins (Spheniscus humboldti) in Chile

Plasma retinol and α-tocopherol concentrations were measured in heparinized blood samples collected from 51 free-ranging adult Humboldt penguins (Sphenicus humboldti) residing at two colonies off the Chilean coast. Thirty samples were collected in April 1992 from penguins inhabiting the Ex-islote de los Pájaros Niños in Algarrobo, Chile. In September 1992, 21 samples were collected from birds inhabiting Isla de Cachagua, Chile. Samples were assayed for retinol, retinyl palmitate, α-tocopherol, γ-tocopherol, lutein, β-cryptoxanthin, lycopene, α-carotene, and β-carotene. Retinol, α-tocopherol, and lutein were detected in all samples, while lycopene and γ-tocopherol were not detected in any. A significantly higher percentage of samples had detectable levels of retinyl palmitate and α-carotene in April (P < 0.001): for β-cryptoxanthin the percentage was higher in September (P < 0.001). Plasma concentrations of α-tocopherol and lutein were higher in September. Alpha-tocopherol concentrations were 1,877.1 ± 99.0 (SEM) μg/dl in April compared to 2.289 ± 122.3 μg/dl in September (P < 0.05); lutein concentrations were 4.16 ± 0.43 μg/dl in April vs. 10.68 ± 1.02 μg/dl in September (P < 0.001). Retinol concentrations were not significantly different (117 ± 8.0 μg/dl in April vs. 105.3 ± 7.6 μg/dl in September). Both physiologic changes associated with season, and the change in locale may have contributed to the differences seen in the assay means and the number of samples with detectable levels. © 1996 Wiley-Liss, Inc.     

Intracardiac injection of matrigel induces stem cell recruitment and improves cardiac functions in a rat myocardial infarction model

Matrigel promotes angiogenesis in the myocardium from ischemic injury and prevents remodelling of the left ventricle. We assessed the therapeutic efficacy of intracardiac matrigel injection and matrigel‐mediated stem cell homing in a rat myocardial infarction (MI) model. Following MI, matrigel (250 μl) or phosphate‐buffered solution (PBS) was delivered by intracardiac injection. Compared to the MI control group (MI‐PBS), matrigel significantly improved left ventricular function (n= 11, P < 0.05) assessed by pressure–volume loops after 4 weeks. There is no significant difference in infarct size between MI‐matrigel (MI‐M; 21.48 ± 1.49%, n= 10) and MI‐PBS hearts (20.98 ± 1.25%, n= 10). The infarct wall thickness of left ventricle is significantly higher (P < 0.01) in MI‐M (0.72 ± 0.02 mm, n= 10) compared with MI‐PBS (0.62 ± 0.02 mm, n= 10). MI‐M hearts exhibited higher capillary density (border 130.8 ± 4.7 versus 115.4 ± 6.0, P < 0.05; vessels per high‐power field [HPF; 400×], n= 6) than MI‐PBS hearts. c‐Kit⁺ stem cells (38.3 ± 5.3 versus 25.7 ± 1.5 c‐Kit⁺ cells per HPF [630×], n= 5, P < 0.05) and CD34⁺ cells (13.0 ± 1.51 versus 5.6 ± 0.68 CD34⁺ cells per HPF [630×], n= 5, P < 0.01) were significantly more numerous in MI‐M than in MI‐PBS in the infarcted hearts (n= 5, P < 0.05). Intracardiac matrigel injection restores myocardial functions following MI, which may attribute to the improved recruitment of CD34⁺ and c‐Kit⁺ stem cells.     

Ethnic Differences in the Responsiveness of Adipocyte Lipolytic Activity to Insulin

Objective: The goal of this study was to quantify differences in lipid metabolism and insulin sensitivity in black and white subjects to explain ethnic clinicopathological differences in type 2 diabetes. Research Methods and Procedures: The in vitro lipolytic activity of adipocytes isolated from obese black and white women was measured in the presence of insulin and isoproterenol. Insulin resistance was assessed in vivo using the euglycemic hyperinsulinemic clamp technique. Results: Fasting plasma levels of insulin and nonesterified fatty acid (NEFA) in black and white women were 67 ± 5 pM vs. 152 ± 20 pM (p < 0.01) and 863 ± 93 μM vs. 412 ± 34 μM (p < 0.01), respectively. Euglycemic hyperinsulinemic clamp studies showed that obese black subjects were more insulin‐resistant than their white counterparts (glucose infusion rates: 1.3 ± 0.2 vs. 2.2 ± 0.3 mg/kg per min; p < 0.05). Isolated adipocytes from white women were more responsive to insulin than those from black women with 0.7 nM insulin causing a 55 ± 4% inhibition of isoproterenol‐stimulated lipolysis compared with 27 ± 10% in black women (p < 0.05). Discussion: The low responsiveness of adipocyte lipolytic activity to insulin in black women in the presence of a relative insulinopenia may account for the high plasma NEFA levels seen in these women, which may, in turn, account for their higher in vivo insulin resistance. High NEFA levels may also contribute to the low insulin secretory activity observed in the obese black females. These data suggest that the pathogenesis of insulin resistance and type 2 diabetes within the black obese community is strongly influenced by their adipocyte metabolism.