Plasma copper and lipid peroxidation in cigarette smokers

Plasma levels of copper and lipid peroxidation were evaluated in 14 smokers as compared to 14 nonsmokers. Plasma copper concentrations were higher in smokers than in nonsmokers (122.5 ± 19.15 vs. 101.5 ± 16.2 μg/dl, P < .01). Plasma lipoperoxidation, evaluated as fluorescent damage products of lipid peroxidation (FDPL), also was higher in smokers than in nonsmokers (20.35 ± 2.6 vs. 17.1 ± 2.95 units of relative fluorescence/ml, P < .01). A significant and positive correlation between the number of cigarettes smoked, expressed as pack years, and the levels of either FDPL (r = .61, P < .025) or copper (r = .55, P < .05) was found. Moreover, a significant and positive relationship between copper and FDPL values was observed in smokers (r = .64; P < .025), but not in nonsmokers. These data indicate that cigarette smoke-related plasma oxidant load may be partly due to enhanced levels of the prooxidant metal copper, potentially suggesting the supplementation of specific antioxidants (e.g., zinc) to counteract cigarette smoke-induced oxidative stress in smokers.     

The effects of in vivo and in vitro non-enzymatic glycosylation and glycoxidation on physico-chemical properties of haemoglobin in control and diabetic patients

The erythrocyte deformability, which is related to erythrocyte internal viscosity, was suggested to depend upon the physico-chemical properties of haemoglobin. In the present study we employed ESR spectroscopy in order to explore further the extent to which the in vivo or in vitro glycation and/or glycoxidation might affect haemoglobin structure and conformation. We revealed that under both in vivo and in vitro conditions the attachment of glucose induced a mobilization of thiol groups in the selected domains of haemoglobin molecules (the increased h₊₁/h₀ parameter of maleimide spin label, MSL; 0.377 ± 0.021 in diabetics vs 0.338 ± 0.017 in controls, n = 12, P < 0.0001). The relative rotational correlation time (τ_c) of two spin labels, TEMPONE and TEMPAMINE, respectively, in erythrocyte insides (5.22 ± 0.42 in diabetics, n = 21 vs 4.79 ± 0.38, n = 16 in controls, P < 0.005) and in the solutions of in vitro glycated haemoglobin, were increased. Neither oxidation nor crosslinking of thiol groups was evidenced in glycated and/or oxidized haemoglobin. In addition, erythrocyte deformability was found to be reduced in type 2 diabetic patients (6.71 ± 1.08, n = 28 vs 7.31 ± 0.96, n = 21, P < 0.015). In conclusion, these observations suggest that: the attachment of glucose to haemoglobin might have decreased the mobility of the Lys-adjacent Cys residues, thus leading to the increased h₊₁/h₀ parameter of MSL. Such structural changes in haemoglobin owing to non-enzymatic glycosylation may contribute to the increased viscosity of haemoglobin solutions (r = 0.497, P < 0.0035) and the enhanced internal viscosity of diabetic erythrocytes (r = 0.503, P < 0.003). We argue that such changes in haemoglobin, and consequently in red blood cells, might contribute to the handicapped oxygen release under tissue hypoxia in the diabetic state.     

Chromosomal aberrations in tire plant workers and interaction with polymorphisms of biotransformation and DNA repair genes

We evaluated chromosomal aberrations in lymphocytes of 177 workers exposed to xenobiotics in a tire plant and in 172 controls, in relation to their genetic background. Nine polymorphisms in genes encoding biotransformation enzymes and nine polymorphisms in genes involved in main DNA repair pathways were investigated for possible modulation of chromosomal damage. Chromosomal aberration frequencies were the highest among exposed smokers and the lowest in non-smoking unexposed individuals (2.5 ± 1.8% vs. 1.7 ± 1.2%, respectively). The differences between groups (ANOVA) were borderline significant (F = 2.6, P = 0.055). Chromosomal aberrations were higher in subjects with GSTT1-null (2.4 ± 1.7%) than in those with GSTT1-plus genotype (1.8 ± 1.4%; F = 7.2, P = 0.008). Considering individual groups, this association was significant in smoking exposed workers (F = 4.4, P = 0.040). Individuals with low activity EPHX1 genotype exhibited significantly higher chromosomal aberrations (2.3 ± 1.6%) in comparison with those bearing medium (1.7 ± 1.2%) and high activity genotype (1.5 ± 1.2%; F = 4.7, P = 0.010). Both chromatid- and chromosome-type aberration frequencies were mainly affected by exposure and smoking status. Binary logistic regression analysis revealed that frequencies of chromatid-type aberrations were modulated by NBS1 Glu185Gln (OR 4.26, 95%CI 1.38–13.14, P = 0.012), and to a moderate extent, by XPD Lys751Gln (OR 0.16, 95%CI 0.02–1.25, P = 0.081) polymorphisms. Chromosome-type aberrations were lowest in individuals bearing the EPHX1 genotype conferring the high activity (OR 0.38, 95%CI 0.15–0.98, P = 0.045). Present results show that exposed individuals in the tire production, who smoke, exhibit higher chromosomal aberrations frequencies, and the extent of chromosomal damage may additionally be modified by relevant polymorphisms.     

Efficiency of asbestos shading for growth of Barki rams during hot summer

Twenty-four growing Barki rams, 5–6 months old with an average body weight of 22 kg, were divided into asbestos shaded and unshaded groups during summer. Ad libitum feeding on roughage with 0.5 kg of concentrates per head per day was practiced. Drinking water was available twice daily in the early morning and afternoon. Biweekly observations included rectal temperature (RT; °C), and respiration rate (RR; breaths per minute) at 06:00 h and 14:00 h were recorded. Meteorological data, plasma glucose, calcium, inorganic phosphorus and packed cell volume were also measured. Results indicated that experimental animals developed hyperthermia during June to September, as evidenced by higher (P < 0.01) RT and RR than normal (40 ± 0.05 and 103.9 ± 3.87 vs. 38.9 ± 0.10 and 40 ± 6.56, respectively). Diurnal variations in these physiological phenomena were closely associated (P < 0.05) with ambient temperature changes. As compared with the unshaded group, providing an asbestos shed reduced (P < 0.05) RT and RR in the hyperthermic animals during the day (39.9 ± 0.07 and 94.7 ± 3.75 vs. 40.1 ± 0.08 and 113.1 ± 4.74, respectively), but it increased (P < 0.05) these parameters during summer nights (39.5 ± 0.05 and 82.4 ± 0.95 vs. 39.2 ± 0.07 and 71.6 ± 2.41, respectively). It also increased (P < 0.05) packed cell volume 1 h after morning drinking (35 ± 0.97 vs. 33.2 ± 0.60); reduced (P < 0.05) plasma glucose (43.3 ± 5.88 vs. 53.2 ± 6.31); caused hypocalcemia (10.9 ± 0.35 vs. 11.5 +- 0.43; P < 0.05) and hypophosphatemia (3.9 ±0.35 vs. 4.6 ± 0.34; P < 0.05) as a result of hyperthermia. Monthly variations in all parameters studied were higher (P < 0.01) during early summer. It is concluded that providing an asbestos shed for growing Barki rams under Egyptian summer conditions will not protect the animals from hyperthermia by day and night, as it interferes with extra body heat dissipation to the surroundings during summer nights. Although the unshaded animals were more hyperthermic during summer days, they tended to be normal during the night.     

Clara cell protein (CC16) in serum and bronchoalveolar lavage fluid of subjects exposed to asbestos

The Clara cell protein (CC16) is a small and readily diffusible protein of 16kDa secreted by bronchiolar Clara cells in the distal airspaces. These epithelial cells are altered in several pulmonary pathological processes induced by various lung toxicants. In the search for a new biomarker of asbestos-induced lung impairment, we used a sensitive immunoassay to determine the levels of CC16 in bronchoalveolar fluid (BALF) and serum of subjects exposed to asbestos compared with a group of healthy controls. In the BALF of asbestos-exposed subjects there was an insignificant trend towards CC16 elevation compared with controls, with a (mean ±SD of 0.81 ±0.65mg l^-1 for asbestos-exposed subjects (n = 23) versus 0.39 ±0.19mg l^-1 for controls (n = 11) (p = 0.09). In serum, CC16 concentration was significantly increased among asbestos-exposed subjects, with values of 27.2 ±24.0 µg l^-1 for asbestos-exposed subjects (n = 34) versus 16.1 ±7.6 µg l^-1 for controls (n = 34) (p = 0.01). Regarding the effects of smoking, there were significant differences between generally lower CC16 levels in serum and BALF (p = 0.05 and 0.001, respectively) of smokers compared with the higher levels in non-smokers. Serum CC16 levels positively correlated with those in BALF, which is consistent with a diffusional transfer of CC16 from the bronchoalveolar space into the serum. No association, however, emerged between the levels of CC16 in serum or BALF and either the duration of asbestos exposure or the severity of the lung impairment as assessed by chest X-ray. These findings suggest that exposure to asbestos elicits early changes in the local and, importantly, also the systemic levels of CC16. This pneumoprotein therefore appears as a promising non-invasive biomarker of asbestos-induced lung injury and occupational disease in both smoking and non-smoking exposed subjects.     

Different neuromuscular recruitment patterns during eccentric, concentric and isometric contractions

Aim. The purpose of this study was to determine the neuromuscular fatigue profiles during 100 s isometric (ISO), concentric (CON), and eccentric (ECC) activity.

Methods. Twelve subjects (age 25.1±3.7 years, mass 70.1±8.2 kg, mean±SD) performed ISO, CON and ECC maximal voluntary contractions and 100 s endurance trials on an isokinetic dynamometer. Raw EMG data were recorded throughout each trial from the rectus femoris of the right limb. Corresponding data for integrated electromyography (IEMG), percentile frequency shifts (MPFS) and peak torque output were divided into five 5 s epochs and subsequently normalised with the first epoch being the reference point, in order to assess changes over time.

Results. There were no significant differences between ECC, CON and ISO peak torque output (211±63 vs 169±41 vs 177±61 Nm; ECC, CON, ISO) and IEMG activity (280±143 vs 305±146 vs 287±143 mV; ECC, CON, ISO) during maximal contractions. Serial reductions in torque output were greatest in ISO in which torque output during the final epoch was 31±13% of initial values, similar to the final torque values in CON (58±15%), but significantly less than ECC (108.6±38.6%; P<0.001) values. In CON and ECC, IEMG was maintained (95±27% and 93±21%; CON and ECC), whereas IEMG for ISO decreased to 38±13% of initial values. The greatest reduction in MPFS occurred in CON (69±10%) compared to ISO (78±9%; P<0.05) and ECC (93±6%; P<0.001).

Conclusion. These data demonstrate distinct neuromuscular fatigue profiles for the different types of muscle contraction. Whereas eccentric activity was largely fatigue resistant, isometric and concentric contractions displayed different neuromuscular fatigue profiles.     

Impaired resistance to oxidation of low density lipoprotein in cystic fibrosis: Improvement during vitamin E supplementation

Antioxidants such as vitamin E protect unsaturated fatty acids of LDL against oxidation. In the ex vivo model used, LDL was exposed to Cu²⁺ ions, a potent prooxidant capable of initiating the oxidation of LDL. The lag time, indicating the delay of conjugated diene formation in LDL due to antioxidant protection, was measured in 54 cystic fibrosis (CF) patients with plasma -tocopherol levels below (Group A, n = 30) or above (Group B, n = 24) 15.9 μmol/L (mean - 2 SD of Swiss population). Patients were reevaluated after 2 months on 400 IU/d of oral RRR--tocopherol. In group A, -tocopherol concentrations in LDL increased significantly from 3.2 ± 1.6 mol/mol LDL to 8.2 ± 2.8 mol/mol (P < 0.001) and lag times increased from 79 ± 33, min to 126 ± 48 min (P < 0.001), whereas in the vitamin E sufficient group B no further increase neither in LDL -tocopherol concentrations or in lag times was observed. LDL oleic acid concentrations were higher, and linoleic acid concentrations were lower in patients than in controls. After efficient vitamin E supplementation, lag times were positively related to LDL -tocopherol (P < 0.01) and negatively to LDL linoleic and arachidonic acid content (P < 0.001). The maximum rate of oxidation correlated positively with linoleic and arachidonic acid concentrations, as did the maximum conjugated diene absorbance. These results indicate that LDL resistance to oxidation is impaired in vitamin E deficient CF patients but can be normalized within 2 months when -tocopherol is given in sufficient amounts. Linoleic and arachidonic acid content exhibit a major influence on the LDL resistance to oxidation.     

Influence of age on activities of antioxidant enzymes and lipid peroxidation products in erythrocytes and neutrophils of Down syndrome patients

Thirty-seven individuals with Down syndrome (DS) were divided into four age categories: (i) 1 to < 6 years, (ii) 6 to < 13 years, (iii) 13 to < 20 years, and (iv) over 20 years. Activities of antioxidant enzymes found in individual age categories were different, but the differences between age groups were not statistically significant. We confirmed significantly higher activities of Cu/Zn superoxide dismutase (SOD) and glutathione peroxidase (GPx) in blood cells of people with DS as compared to 35 controls, which consisted, for the first time, of siblings of children with DS. No significant differences were found in activities of catalase and glutathione reductase in DS vs. controls. A significant difference was observed in serum concentration of malondialdehyde (MDA) in DS vs. controls (8.39 +/- 0.34 micromol/l vs. 7.34 +/- 0.27 micromol/l; p = .021) and concentration of MDA in erythrocytes of individuals with DS between the third and fourth age group (p = .05). In DS persons, an elevated ratio of SOD to catalase plus GPx with respect to the controls in all age categories was found, suggesting oxidative imbalance, potentially contributing to accelerated aging observed in these persons.     

Cardiovascular and thermoregulatory responses to repeated anticholinesterase administration

1. 1.|Pyridostigmine administration decreased resting heart rate by 11 ± 7 beats/min and resting oesophageal temperature by 0.23 ± 12°C after 50 h (P < 0.05). In addition, red blood cell cholinesterase activity was decreased an average of 43 ± 7% after 50 h of pyridostigmine treatment.

2. 2.|The lower heart rates and core temperatures at rest were continued during high intensity exercise in a 35°C environment. Whole body sweating was 12 ± 18% higher (P = 0.20) during exercise in the heat after 50 h of pyridostigmine treatment.

3. 3.|Repeated anticholinesterase administration had little effect on cardiovascular and thermoregulatory responses during high intensity exercise.

A method to reduce the invasiveness of fetal catheterization in the cow

Surgical intervention in general anesthesia (GA) of the cow in late gestation is a stressful condition for both mother and fetus, potentially leading to premature delivery or fetal death. The present study hypothesized that fetal catheterization at days 246–253 (90% of gestation) is done with less physical and metabolic stress for the mother and fetus, when the surgery is performed on a standing cow and local anesthesia (LA) rather than on a recumbent cow in general anesthesia. Fetal and uterine maternal intra-vascular catheters were implanted during general anesthesia (GA, n=24) or local analgesia (LA, n=7). Blood gases and metabolite levels in the fetal calves and their mothers were measured during surgery and for 5 days post-operatively. During surgery, venous blood pH was higher (7.44±0.01 versus 7.39±0.01, P<0.05) and hemoglobin and oxygen contents lower in LA cows compared with GA cows (9.3±0.3 mg/dl versus 11.8±0.2 mg/dl, P<0.001 and 10.1±0.3 ml/dl versus 12.6±0.6 ml/dl, P<0.05). The differences between the two groups of fetuses reflected those of their dams in that LA fetuses showed lower arterial oxygen pressure (18.3±1.4 mmHg versus 24.8±1.4 mmHg, P<0.05) and hemoglobin (7.81±0.30 mg/dl versus 9.22±0.21 mg/dl P<0.01) and furthermore, they also showed higher blood glucose (2.4±0.2 mM versus 1.4±0.1 mM, P<0.01). During the 5 days post-surgery, 10 GA fetuses (42%) and 1 LA fetus (14%) died in utero. Bacterial contamination was implicated in six of the GA deaths and in the one LA death. In the dams with surviving calves, differences in hemoglobin (9.49±0.21 mg/dl versus 11.17±0.23 mg/dl P<0.001) and O₂ct (10.9±0.3 ml/dl versus 12.5±0.5 ml/dl, P<0.05) were still present, and in addition, blood glucose was higher in LA versus GA cows (4.3±0.2 mM versus 3.8±0.1 mM, P<0.05). The choice of surgical method did not affect post-surgery blood chemistry in the surviving fetuses, except that the higher blood glucose in the LA fetuses at surgery tended to be maintained also post-operatively (2.0±0.2 mM versus 1.5±0.1 mM, P=0.07). The observed differences in blood chemistry parameters between the two methods of surgery and possibly in the fetal death may be explained by differences in catheterization method and the associated differences in physical and metabolic stress during and after surgery. Thus, surgery upon a standing cow in local anesthesia should be considered as an alternative to surgery in universal anesthesia for fetal catheterization in the cow in late gestation.     

The effects of ovariectomy and progesterone on peripheral aromatization in the female rhesus monkey

We investigated the acute effects of surgery, i.e. ovariectomy, the long-term effects of ovariectomy, and the effects of progesterone on the peripheral aromatization of androstenedione in rhesus monkeys (Macaca mulatta). For the acute effects of surgery, 7 rhesus monkeys were given a pulse of [³H]androstenedione/[¹⁴C]estrone 2 weeks before and immedately after ovariectomy. In each case all urine was collected for 4 days and analyzed for radioactivity as estrone glucuronide and the peripheral aromatization calculated from the isotope ratios. Similarly, 5 monkeys were studied before and 18 months after ovariectomy. The acute effects of surgery resulted in a significant decrease in the peripheral aromatization of androstenedione to estrone from a mean±SE of 0.94 ± 0.26 to 0.61 ± 0.19%, P = 0.0452. Conversely, the long-term effects of ovariectomy resulted in a significant increase in peripheral aromatization from 0.38 ± 0.06 to 0.67 ± 0.12%, P = 0.0207. In 7 monkeys the peripheral aromatization was measured before and 10 days after the administration of progesterone, 100 mg in oil. There was no difference in peripheral aromatization before, 0.62 ± 0.04% and after progesterone, 0.58 ± 0.05%, P = 0.10. We conclude that the acute stress of ovariectomy, or possibly the loss of ovarian aromatizing tissue, results in a decline in peripheral aromatization, but ovariectomy will have the long-term effect of an increase in aromatization, and that the presence or absence of progesterone does not play a role.     

Peripheral insulin administration attenuates the increase in neuropeptide Y concentrations in the hypothalamic arcuate nucleus of fasted rats

Fasting increases neuropeptide Y (NPY) concentrations in the arcuate nucleus (ARC), its site of synthesis, and in other regions of the rat hypothalamus. Neuropeptide Y is a potent central orexigenic agent and may therefore stimulate appetite during fasting. We tested the hypothesis that low plasma insulin levels stimulate ARC levels of NPY in fasted rats. Compared with freely fed controls (n = 8), rats fasted for 72 h (n = 8) showed significantly lower plasma insulin levels (28.9 ± 1.6 vs. 52.6 ± 5.7 pmol/l; p < 0.001) and higher ARC NPY concentrations (14.2 ± 1.8 vs. 8.4 ± 2.2 fmol/μg protein; p < 0.001). Fasted rats treated with subcutaneous insulin (5 U/kg/day; n = 10), which nearly normalized plasma insulin (46.6 ± 2.8 pmol/l), showed intermediate ARC NPY levels (11.2 ± 1.4 fmol/μg protein; p < 0.01 vs. controls and untreated fasted rats). Insulin administered peripherally, therefore, attenuates fasting-induced NPY increases in the ARC, supporting the hypothesis that hypoinsulinemia stimulates hypothalamic NPY.     

Flash-induced absorption changes in Photosystem I,Radical pair or triplet state formation?

Absorption changes induced in chlorophyll protein (CP 1) particles by short laser flashes have been analyzed in order to decide whether a state lasting for a few microseconds at 21°C or 800 μs at 10 K corresponds to the biradical P-700⁺ ... A⁻₁ (A₁ being a chlorophyll a) or to a triplet state produced in a submicrosecond recombination of the preceding state. At 21°C the spectrum of the flash-induced ΔA (720–870 nm) presents a flat-topped band from 740 to 820 nm, clearly different from that of P-700⁺. A saturation curve (ΔA vs. laser energy), obtained with a 2 or 10 ns laser pulse, indicates that ΔA saturates at a value 2- or 3-times smaller than that expected on the basis of the chemical oxidation of P-700. At 21°C the size of flash-induced ΔA is slightly decreased (5–15%) when the sample is subjected to a 400 G magnetic field. The kinetics of decay are not affected; they are not affected either by the oxygen concentration. At 10 K the spectrum of the flash-induced ΔA has been measured between 650 and 1700 nm. Between 650 and 720 nm, the spectrum presents only one major negative peak at 702 nm; it is quite different from that due to the chemical oxidation of P-700 (which has additional peaks at 688 and 677 nm). Between 720 and 870 nm, the spectrum is identical to that obtained at 21°C. Above 870 nm, the spectrum includes a broad band around 1250 nm, which is absent in P-700⁺. A saturation curve leads to a maximum ΔA greater than that at 21°C and which is also greater with a 1 μs dye laser flash than with a 10 ns ruby laser flash. An analysis of the spectral data indicates that these do not fit correctly with the hypothesis of a contribution of P-700⁺ and of a chlorophyll a anion radical. They fit more closely with the hypothesis of a triplet state of P-700, a hypothesis which is discussed in relation to other experimental data.     

Phenacetin acts as a weak genotoxic compound preferentially in the kidney of DNA repair deficient Xpa mice

Cell cycle checkpoints and DNA repair capacity are critical for the maintenance of genome integrity. We hypothesized that, in comparison to healthy controls, esophageal cancer patients might have a higher frequency of deficiencies in cell cycle checkpoints and/or DNA repair system. Using flow cytometry and comet assay, we assessed the γ-radiation-induced S phase and G2-M phase accumulation, and benzo(a)pyrene-diol-epoxide (BPDE)- and γ-radiation-induced DNA damage, in peripheral blood lymphocytes of 99 newly diagnosed esophageal cancer patients and 112 age-, gender-, and ethnicity-matched healthy controls. The mean γ-radiation-induced cell accumulation at G2-M phase was significantly lower in esophageal cancer patients than the control subjects (case versus control: 5.27% ± 5.11% versus. 7.06% ± 5.04%, P = 0.013). The less G2-M phase cell accumulation resulted in a significant increased risk for esophageal cancer with an odds ratio of 2.08 (95% confidence interval 1.15–3.77). After normalization to baseline S fraction, the radiation-induced increment in the 4N/2N ratio was also significantly lower in esophageal cancer patients than in controls (case versus control: 0.76% versus 1.04%, P = 0.0039). The less increment in the radiation-induced 4N/2N ratio was associated with 2.24(95% confidence interval 1.22–4.11)-fold increase of esophageal cancer risk. We also compared the mutagen-induced DNA damage level among individuals with different S or G2-M phase cell accumulation. We found that the less G2-M phase accumulation was associated with both high BPDE induced and γ-radiation-induced DNA damage in the healthy controls (P for trend = 0.023 and 0.015, respectively). Similar pattern was observed for S phase accumulation (P for trend = 0.033 and 0.022, respectively). However, such association was not seen in esophageal cancer patients. This study provides the first molecular epidemiologic evidence linking increased esophageal cancer risk with defects in cell-cycle checkpoints and DNA repair capacity.     

Variation in δC values for the seagrass Thalassia testudinum and its relations to mangrove carbon

Carbon isotope ratios (¹³C/¹²C) were measured for the leaves of the seagrass Thalassia testudinum Banks ex König and carbonates of shells collected at the seagrass beds from seven sites along the coast of southern Florida, U.S.A. The δ¹³C values of seagrass leaves ranged from −7.3 to −16.3‰ among different study sites, with a significantly lower mean value for seagrass leaves from those sites near mangrove forests (−12.8 ± 1.1‰) than those far from mangrove forests (−8.3 ± 0.9‰; P < 0.05). Furthermore, seagrass leaves from a shallow water area had significantly lower δ¹³C values than those found in a deep water area (P < 0.01). There was no significant variation in δ¹³C values between young and mature leaves (P = 0.59) or between the tip and base of a leaf blade (P = 0.46). Carbonates of shells also showed a significantly lower mean δ¹³C value in the mangrove areas (−2.3 ± 0.6‰) than in the non-mangrove areas (0.6 ± 0.3‰; P <0.025). In addition, the δ¹³C values of seagrass leaves were significantly correlated with those of shell carbonates (δ¹³C seagrass leaf = −9.1 + 1.3δ¹³C shell carbonate (R² = 0.83, P < 0.01)). These results indicated that the input of carbon dioxide from the mineralization of mangrove detritus caused the variation in carbon isotope ratios of seagrass leaves among different sites in this study.     

Influence of classification levels of ram sexual activity on spring breeding ewes

Ram lambs (7–8 months old) and mature rams (19–20 months old) were used to evaluate the effect of classification levels of male sexual performance on reproductive performance of ewes during spring breeding. In Exp. 1, sexually active ram lambs with high (1.8±0.3; n=5) and low (0.9±0.2; n=5) sexual performance scores (HP and LP; mean±S.E.M.) were used in single sire breeding pens. Ewes (n=305) were stratified by age and assigned to 10 pens for 34 days starting in late March. For Exps. 2 and 3, two replicates were conducted for 2 years with sexually active mature rams in a single sire mating scheme. For Exp. 2, HP rams (n=5) averaged 3.6±0.2 ejaculations and LP rams (n=7) 1.8±0.2 ejaculations for sexual performance scores based on nine, 30 min serving capacity tests (SCT). Polypay ewes (n=152 to 153 per year) were stratified by age and assigned to pens each year for 34–38 days starting in late March for years 1 and 2. For Exp. 3, HP rams (n=6) averaged 3.7±0.1 ejaculations and LP rams (n=10) 2.3±0.1 ejaculations for sexual performance scores based on 18, 30 min SCT. Polypay ewes (n=229 in year 3 and n=244 in year 4) were stratified by age and assigned to pens each year for 34 days starting in late March. In Exp. 1, lambing rates for ewes bred to HP versus LP ram lambs did not differ (65.8 versus 53.0; P=0.20). Prolificacy tended (P=0.06) to be increased by 0.1 lambs in ewes bred by LP ram lambs. Total number of lambs born per ewe present at lambing, and lambing distribution were not altered by HP and LP ram lambs. In Exp. 2, lambing rates for fall-lambing ewes bred to mature HP or LP rams did not differ (58.1 versus 60.1; P=0.78). In Exp. 3, lambing rates for fall-lambing ewes bred to mature HP or LP rams did not differ (74.3 versus 69.0; P=0.35). There was no difference (P>0.10) between years for Exp. 2 or Exp. 3, and mature HP and LP rams did not affect the other reproductive variables monitored. Analyses of the combined data for Exps. 2 and 3 indicated only a year difference (P<0.001) in lambing rates and total lambs born. Present studies indicate that different sexual performance classifications for ram lambs and mature rams did not alter lambing rates or distribution of lambing of Polypays bred in late March to April. These results indicate that HP and LP, sexually active, Polypay rams and ram lambs with average to high quality semen can provide a source of rams for spring breeding Polypays in ambient conditions and that there was no advantage to using HP over sexually active LP ram lambs or rams.     

Elevated F2-isoprostanes in thalassemic patients

This study was aimed at investigating oxidative stress in thalassemic patients by measurement of the oxidative damage biomarker, F₂-isoprostanes (F₂-IsoPs), using gas chromatography-mass spectrometry. The results showed that the mean value of urinary F₂-IsoPs, normalized with creatinine, in the thalassemic group was significantly higher than that from healthy subjects (3.38 ± 2.15 ng/mg creatinine vs 0.86 ± 0.55 ng/mg creatinine, respectively), and the mean value of plasma total F₂-IsoPs in the thalassemic group was also significantly higher than that from healthy subjects (0.39 ± 0.15 ng/ml vs 0.18 ± 0.03 ng/ml, respectively). Serum ferritin, erythrocyte superoxide dismutase (SOD), glutathione peroxidase, glutathione, and TBARS levels after treatment of erythrocytes with H₂O₂ were also investigated, and serum ferritin and erythrocyte SOD levels were significantly higher in thalassemic patients. Our findings are consistent with oxidative stress in thalassemia patients.     

Alpha-tocopherol content and alpha-tocopherol transfer protein expression in leukocytes of children with acute leukemia

-Tocopherol (a form of vitamin E) is a fat-soluble vitamin that can prevent lipid peroxidation of cell membranes. This antioxidant activity of -tocopherol can help to prevent cardiovascular disease, atherosclerosis and cancer. We investigated the -tocopherol level and the expression of -tocopherol transfer protein (-TTP) in the leukocytes of children with leukemia. The plasma and erythrocyte -tocopherol levels did not differ between children with leukemia and the control group. However, lymphocytes from children with leukemia had significantly lower -tocopherol levels than lymphocytes from the controls (58.4±39.0 ng/mg protein versus 188.9±133.6, respectively; p0.05), despite the higher plasma -tocopherol/cholesterol ratio in the leukemia group (5.83±1.64 μmol/mmol versus 4.34±0.96, respectively; p0.05). No significant differences in the plasma and leukocyte levels of isoprostanes (the oxidative metabolites of arachidonic acid) were seen between the leukemia patients and controls. The plasma level of acrolein, a marker of oxidative stress, was also similar in the two groups. Investigation of -TTP expression by leukocytes using real-time PCR showed no difference between the two groups. These findings suggest that there may be comparable levels of lipid peroxidation in children with untreated leukemia and controls, despite the reduced -tocopherol level in leukemic leukocytes.     

Increase in oxidative damage to lipids and proteins in skeletal muscle of uremic patients

Muscle weakness and reduced exercise capacity are frequent complaints of patients with chronic uremia. Several lines of evidence have suggested that chronic uremia result in a state of increased oxidative stress. Reactive oxygen species (ROS) and free radicals are capable of damaging lipids and proteins but it remains unclear whether oxidative damage plays a role in the skeletal myopathy commonly seen in chronic uremia. In this cross-sectional study, we compared the levels of oxidative damage to proteins and lipids of skeletal muscle from 40 chronic uremic patients and 20 age- and sex-matched healthy subjects. Protein carbonyls were determined by a spectrophotometric method to assess the oxidative damage to proteins. Our results showed that the mean content of protein carbonyls in skeletal muscles was significantly elevated in the hemodialysis patients ( 3.78 ±0.14 nmol of 2,4-dinitrophenyl-hydrazone per mg of protein) as compared to healthy controls (2.97 ±0.28 nmol per mg of protein, p =0.017 vs normal controls). In addition, we found that the mean malondialdehyde (MDA) level was also significantly increased in the uremic patients compared to healthy controls. Further analysis revealed that there was an age-dependent increase in both oxidative damages in these patients. Regression analysis between plasma protein carbonyl and MDA levels showed a significant correlation between these two parameters ( r =0.43, p =0.002). The finding of increased oxidative damage to protein and lipids provide support that oxidative damage may play a role in the pathogenesis of skeletal myopathy in chronic uremic patients on hemodialysis.     

Microhabitat selection and daily movements of two rodents (Necromys lasiurus and Oryzomys scotti) in Brazilian Cerrado, as revealed by a spool-and-line device

Studies on patterns of habitat use by mammals are necessary for understanding the mechanisms involved in their distribution and abundance. In this study, we used the spool-and-line method to investigate habitat utilization by two sigmodontine rodents from Brazilian Cerrado, Necromys lasiurus and Oryzomys scotti. We conducted the study in a Cerrado area in central Brazil (15°56′S and e 47°56′W) where the animals were caught in an area of 7.68 ha of Cerrado sensu stricto. Captured individuals were marked, equipped with a spool-and-line device, and released at the same capture point. The next day we followed the thread to record their daily movements and find their nests. To investigate microhabitat selection we compared habitat characteristics along trails of each studied species with general habitat characteristics of the study area. Although the mean 24-h distance was greater for N. lasiurus (mean ± SE: 41.9 ± 42.2 m, N=3) than for O. scotti (28.7 ± 14.2 m, N=6) this difference was not significant (Mann–Whitney test, U=26, P>0.6). We detected significant differences among observed microhabitats variables of both species and available microhabitat characteristics as determined by discriminant analysis (Wilks′s lambda F=3.001; df=14, 116; P<0.001). Both species were associated to microhabitat characteristics whose values differed markedly from the overall available habitat. Along the first canonical discriminant function of the DFA both them were associated with greater grass height than the mean height available and along the second axis N. lasiurus selected areas with higher fruit availability and more shelters than those selected by O. scotti. For stronger inferences regarding differential patterns of habitat utilization by Cerrado rodents we suggest the simultaneous use of both spool-and-line and standard trapping methods.