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.     

Effects of PMSG and ram contact on the reproductive performance of progestagen-treated ewes during breeding and anestrous seasons

The objective of this study was to evaluate the efficacy of combinations of PMSG treatment and ram contact on the reproductive performance of progestagen-treated ewes during three different times of the year, Febraury (early anestrus), July (late anestrus) and October (breeding season). A total of 109 multiparous Dorset ewes was used. Ewes were treated with intravaginal progestagen pessaries for 12 days, injected with 500 IU PMSG at pessary removal and either isolated from rams prior to mating (n = 12, February; n = 12, July; n = 8, October) or exposed to rams during pessary treatment (n = 17, February; n = 12, July; n = 8, October). A third treatment group (n = 18, February; n = 6, July; n = 8, October) received pessaries and ram exposure but no PMSG. An additional treatment of progestagen pessaries alone was included in October (n = 8). There were no differences among treatments in their ability to induce estrus at different times of the year, but incidence of estrus tended (P < 0.10) to be lower for PMSG treatment during the July breeding. During February, the use of pessaries with PMSG treatment increased (P < 0.05) conception and lambing rates, whereas ram contact was without any beneficial effects. The trend was reversed during July breeding, when ram contact increased (P < 0.05) fertility of progestagen-treated ewes compared with other treatment combinations. Pessaries alone were sufficient to attain acceptable levels of fertility and fecundity in October.     

Dynamics of indirect symptoms of skeletal muscle damage after stretch-shortening exercise

Healthy untrained men (age 20.4 ± 1.7 years, n = 20) volunteered to participate in an experiment in order to establish dynamics of indirect symptoms of skeletal muscle damage (ISMD) (decrease in maximal isometric voluntary contraction torque (MVCT) and torque evoked by electrostimulation at different frequencies and at different quadriceps muscle length, height (H) of drop jump (DJ), muscle soreness and creatine kinase (CK) activity in the blood) after 100 DJs from 0.75 m height performed with maximal intensity with an interval of 20 s between the jumps (stretch-shortening exercise, SSE). All ISMDs remained even 72 h after SSE (P < 0.01–0.001). The muscle experienced greater decrease (P < 0.01) in torque evoked by electrostimulation (at low stimulation frequencies and at short muscle length in particular) after SSE than neuromuscular performance (MVCT and H of DJ) which demonstrated secondary decrease (P < 0.01) in neuromuscular performance during the first 48 h after SSE. Within 24–72 h after the SSE the subjects felt an acute muscle pain (5–7 points approximately) and the CK activity in the blood was significantly increased up to 1200 IU/L (P < 0.001). A significant correlation between decrease in MVCT and H of DJ 24–48 h after SSE on the one hand and muscle soreness registered within 24–48 h after SSE on the other was observed, whereas correlation between the other indirect symptoms of skeletal muscle damage was not significant.     

Reversal of sexual impotence in male patients with chronic obstructive pulmonary disease and hypoxemia with long term oxygen therapy

Erectile impotence is commonly encountered in male patients with respiratory failure and hypoxia. In this study, 42% of the patients experienced reversal of sexual impotence during long term oxygen therapy (LTOT). We examine the association between sexual impotence, gonadal axis hormones, hypoxia, and oxygen therapy. Nineteen sexually impotent male patients eligible for LTOT (pO₂ < 7.3 kPa during stable disease) and with sexual impotence received oxygen therapy for 1 month (n = 12) or 24 h (n = 7). pO₂, LH, FSH, testosterone, and SHBG (sex hormone binding globulin) were monitored. Five of 12 patients receiving oxygen for 1 month regained sexual potency. The responders showed a significant increase in arterial pO₂ and serum testosterone, and a decline in SHBG compared to non-responders. None of the patients receiving oxygen for 24 h experienced reversal of sexual impotence, despite a significant increase in pO₂. In these patients, serum testosterone did not increase significantly. Reversal of sexual impotence may be achieved in some patients with respiratory failure. The oxygen therapy must, however be administered for an adequate length of time.     

骶神经电刺激对急性脊髓损伤大鼠肠黏膜免疫屏障功能的影响*

目的:观察骶神经根电刺激对急性完全性脊髓损伤大鼠肠黏膜免疫屏障功能的影响。方法:56只Wistar大鼠分为正常组(SG=8只)、脊髓损伤组(CG=24只)和骶神经电刺激组(EG=24只)。CG、EG (分别设24、48和72 h 组,8只/组)。CG、EG大鼠均于全麻下用Fehlings法98 g动脉瘤夹横行钳夹行脊髓损伤并植入骶神经刺激电于右侧骶3神经孔。CG不进行干预,EG行骶神经电刺激。刺激参数:电压4 V,波宽210 μs,频率15 Hz,刺激10 s,间歇20 s。每次持续10 min,间歇10 min,共2 h。早8:00-10:00,晚6:00-8:00两次。分组采集标本,进行HE染色光镜、透射电镜组织学观察、Western blot 方法检测组织锌指蛋白A20、NOD2和CD68蛋白表达量。结果:① 肠道形态学观察:光镜和电镜观察脊髓损伤后黏膜结构破坏明显,肠腔细菌和杂质进入破损的肠黏膜上皮细胞、M细胞和经细胞间连接缝隙进入黏膜下,引起局部炎症反应;经电刺激后均有了很大程度改善。② 锌指蛋白A20:与SG相比,CG各小组A20表达均明显降低(P＜0.01);与SG、CG相比,EG各小组A20的表达均明显升高(P＜0.01)。NOD2:与SG比,CG各组NOD2的表达明显升高(24 h、72 h P＜0.05;48 h P＜0.01);与CG比,EG 48 h、72 h NOD2的表达明显降低( 48 h P＜0.01,72 h P＜0.05);与SG相比,EG各组NOD2表达均无统计学意义。CD68:与SG、EG比,CG各组CD68的表达均明显升高(P＜0.01);与SG相比,EG24 h、48 h组NOD2表达明显升高(P＜0.01),72 h组无统计学意义。结论:电刺激S3神经根能保护肠黏膜机械屏障,减少病原体入侵,改善肠黏膜免疫屏障功能。     

Serum malondialdehyde: possible use for the clinical management of chronic hepatitis C patients

Serum lipid peroxidation products are increased in inflammatory liver disease and, as we previously reported, also in chronic hepatitis C. We have performed a specific assay of malondialdehyde, the reported most abundant product of lipid peroxidation, in serum of twenty four chronic hepatitis C patients, before, during, and after interferon treatment. Liver biopsies were performed in each patient before and after interferon treatment. The results show higher serum malondialdehyde values in chronic hepatitis C patients than healthy subjects (n = 68) before interferon treatment (p < .001). Mean value of serum malondialdehyde levels after interferon treatment was significantly lower than before it (p < .002). Associating the histopathological findings in each of the 48 biopsies performed, with serum malondialdehyde and alanine aminotransferase activity levels, of the sample obtained the same day of biopsy, a much better correspondence with the histopathological severity was observed for malondialdehyde concentration than for alanine aminotransferase activity. These levels decreased significantly after interferon treatment. However, when the patients were grouped in responding (group I; n = 9) and non-responding (group II; n = 15) to interferon treatment, according to the histopathological findings before and after interferon, the values of group I before interferon treatment were significantly higher than group II (p < .03). Thus, a potential predictive value could be ascribed to the serum malondialdehyde levels before interferon treatment in these patients. We propose the utility of the specific assay of malondialdehyde for the clinical management of chronic hepatitis C patients.     

Elevated breath pentane in heart failure reduced by free radical scavenger

Pentane, a product of lipid peroxidation, has been detected in situations involving ischemic injury. Such injury may be limited if lipid peroxidation can be controlled by antioxidants. The role of lipid peroxidation in chronic heart failure (CHF) was assessed by measuring breath pentane in patients with CHF vs. age matched controls. The effect of a free radical scavenger on pentane released during CHF was also measured. Pentane levels were correlated with the daily dose of captopril, a sulfhydril-containing drug used to treat CHF, which is an angiotensin converting enzyme inhibitor. To separate the scavening effects of captopril from the pharmacologic effects of converting enzyme inhibitors, a crossover study using a nonsulfhydril inhibitor was used. Patients with CHF excreted (p < 0.005) hich concentrations of pentane (5.7 ± 2.1 vs. control 3.6 ± 1.2 nmol/l). Patients treated with captopril also had significantly higher (p < 0.05) excretion of pentane than the control patients (4.7 ± 1.3 vs. 3.6 ± 1.2 nmol/l). The dose of captopril was inversely proportional to the concentration of pentane excreted (r = 0.55, p < 0.05). Pentane excretion during captopril therapy was significantly lower before (p < 0.01) and after (p < 0.02) nonsulfhydril inhibitor therapy. Conclusion: breath pentane is elevated in CHF and it can be reduced by a free radical scavenger. This reduction of pentane excretion is not a converting enzyme inhibitor class effect.     

Oxidation of glutathione and cysteine in human plasma associated with smoking

Cigarette smoking contributes to the development or progression of numerous chronic and age-related disease processes, but detailed mechanisms remain elusive. In the present study, we examined the redox states of the GSH/GSSG and Cys/CySS couples in plasma of smokers and nonsmokers between the ages of 44 and 85 years (n = 78 nonsmokers, n = 43 smokers). The Cys/CySS redox in smokers (−64 ± 16 mV) was more oxidized than nonsmokers (− 76 ± 11 mV; p < .001), with decreased Cys in smokers (9 ± 5 μM) compared to nonsmokers (13 ± 6 μM; p < .001). The GSH/GSSG redox was also more oxidized in smokers (−128 ± 18 mV) than in nonsmokers (−137 ± 17 mV; p = .01) and GSH was lower in smokers (1.8 ± 1.3 μM) than in nonsmokers (2.4 ± 1.0; p < .005). Although the oxidation of GSH/GSSG can be explained by the role of GSH in detoxification of reactive species in smoke, the more extensive oxidation of the Cys pool shows that smoking has additional effects on sulfur amino acid metabolism. Cys availability and Cys/CySS redox are known to affect cell proliferation, immune function, and expression of death receptor systems for apoptosis, suggesting that oxidation of Cys/CySS redox or other perturbations of cysteine metabolism may have a key role in chronic diseases associated with cigarette smoking.     

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.     

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.     

Effects of a Novel, Low-Molecular Weight Inhibitor of Lipid Peroxidation on Ischemia–Reperfusion Injury in Isolated Rat Hearts and in Cultured Cardiomyocytes

We investigated the effect of H290/51, a novel, low-molecular-weight inhibitor of lipid peroxidation, on cardiac ischemia–reperfusion injury. Lactate dehydrogenase (LD) release from cultured cardiomyocytes exposed to 1 h hypoxia and 4 h reoxygenation was measured after pretreatment with different concentrations of H290/51. In another series, Langendorff-perfused rat hearts were exposed to 30 min global ischemia and 60 min reperfusion (n = minimum 10 in each group): 1. Control ischemia–reperfusion. 2. Vehicle throughout the experiment. 3. Vehicle during stabilization, and H290/51 (10⁻⁶ mol/l) during reperfusion. 4. H290/51 throughout the experiments. During reoxygenation of isolated cardiomyocytes, H290/51 dose dependently inhibited LD release with an pIC₅₀ value of 7.2 ± 0.4 (mean ± SEM), with 10⁻⁶ mol/l as the lowest efficient concentration. In isolated hearts ischemia–reperfusion induced severe reperfusion arrhythmias, reduced left ventricular developed pressure (LVDP) and coronary flow (CF), and increased LV end-diastolic pressure (LVEDP). LD activity in the effluent increased. H290/51 throughout perfusion (group 4) reduced the occurrence of severe reperfusion arrhythmias (p < .0001), attenuated the decrease of LVDP (p < .008), and CF (p < .006), the increase of LVEDP (p < .008), and the release of LD (p < .002). Tissue contents of thiobarbituric acid-reactive substances did not increase during reperfusion in controls, but was reduced in group 4 (p < .004). H290/51 given only during reperfusion (group 3) tended to improve cardiac function, but significantly so only for increase of CF (p < .01). The lipid peroxidation inhibitor H290/51 attenuated cardiac injury induced by ischemia–reperfusion.     

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.     

Prognostic value of pS2 protein and receptors for epidermal growth factor (EGF-R), Insulin-like growth factor-1 (IGF-1-R) and somatostatin (SS-R) in patients with breast and ovarian cancer

The prognostic value of EGF-R, IGF-1-R and SS-R, and of cytosolic estrogen-regulated pS2 protein, was studied in patients (pts) with primary breast and advanced ovarian cancer. Ovarian cancer tissues were negative for pS2 (by immunoradiometric assay) IGF-1-R and EGF-R contents (by ligand binding assay, LBA) were of no or moderate prognostic value for breast cancer pts (n = 214). For advanced ovarian cancer pts, EGF-R content determined by LBA (n = 55) showed no prognostic value, whereas EGF-R status (n = 55) determined by immunohistochemistry (MoAb 2E9) signiificantly correlated with progression of disease (P < 0.05). In breast cancer pts, both SS-R and pS2 showed no association with tumor size, nodal status and grade. For pS2 the best cut-off level with respect to relapse-free (RFS) and overall survival (OS) was found to be 11 ng/mg protein. Both SS-R (1 g% SS-R+, n = 135; P < 0.04) and pS2 (27% pS2+, n = 197; P < 0.001), which were mainly positive in ER+ tumors, were of prognostic value, especially within the subgroups with ER+/PgR+ tumors. Also within N+ and No pts the 5-yr RFS and OS showed a difference between pS2+ and pS2- (33 and 54% for N+, and 31 and 13% difference for No pts). In summary, SS-R and pS2 are valuable pronosticators in breast cancer pts, and prognostic significance of EGF-R in ovarian cancer pts needs further study.     

Biopsied and vitrified bovine embryos viability is improved by trans10, cis12 conjugated linoleic acid supplementation during in vitro embryo culture

Bovine embryos cultured in serum-containing media abnormally accumulate lipids in the cytoplasm. This is well known to contribute to their higher susceptibility to cryopreservation and biopsied embryos are even further susceptible. We aimed to improve in vitro produced (IVP) embryos resistance to micromanipulation and cryopreservation by supplementing serum-containing media with trans-10, cis-12 conjugated linoleic acid (t10, c12 CLA). The effect of t10, c12 CLA on lipid deposition and embryonic development was also tested. After in vitro maturation and fertilization (IVF day = D0), zygotes were cultured on granulosa cells + M199 + 10% serum + 100 μM GSH supplemented with 100 μM of t10, c12 CLA (CLA group, n = 1394) or without supplementation (control group, n = 1431). Samples of D7/D8 embryos were observed under Nomarsky microscopy for lipid droplets evaluation while others were biopsied and vitrified (group B-Control, n = 24; group B-CLA, n = 23). Non-biopsied embryos were also frozen (group NB-Control, n = 49; group NB-CLA, n = 45). Biopsied cells were used for embryo sex determination. Postwarming embryo survival and viability were determined at 0 and 24 h of culture, respectively. Supplementation of t10, c12 CLA did not influence cleavage, embryo sex ratio, D7/D8 embryo rate or morphological quality. CLA embryos had higher number of small lipid droplets (P ≤ 0.003) and a smaller (P < 0.001) fat embryo index being leaner (P = 0.008) than control embryos. Embryo postwarming survival was higher in B-CLA than in B-control group (95.0 ± 7.0% versus 62.5 ± 7.9%; P < 0.001). After 24 h of culture, the viability (expansion rate) of biopsied embryos and nonbiopsied embryos, cultured with t10, c12 CLA was higher than control embryos (B-CLA = 64.6 ± 4.4% and B-control = 27.5 ± 2.5%, P = 0.01; NB-CLA = 86.0 ± 3.5% and NB-Control = 68.6 ± 7.0%, P = 0.05). Results showed that supplying t10, c12 CLA to serum-containing media decreases embryo cytoplasmic lipid deposition during in vitro culture and significantly improves resistance of IVP embryos to micromanipulation and cryopreservation.     

Oestradiol and the preovulatory surges of luteinising hormone and follicle stimulating hormone in ewes during the breeding season and transition into anoestrus

This study was designed to see if giving exogenous oestradiol, during the follicular phase of the oestrous cycle of intact ewes, during the breeding season or transition into anoestrus, would alter the occurrence, timing or magnitude of the preovulatory surge of secretion of luteinising hormone (LH) or follicle stimulating hormone (FSH). During the breeding season and the time of transition, separate groups of ewes were infused (intravenously) with either saline (30 ml h⁻¹; n = 6) or oestradiol in saline (n = 6) for 30 h. Infusion started 12 h after removal of progestin-containing intravaginal sponges that had been in place for 12 days. The initial dose of oestradiol was 0.02 μg h⁻¹; this was doubled every 4 h for 20 h, followed by every 5 h up to 30 h, to reach a maximum of 1.5 μg h⁻¹. Following progestin removal during the breeding season, peak serum concentrations of oestradiol in control ewes were 10.31 ± 1.04 pg ml⁻¹, at 49.60 ± 3.40 h after progestin removal. There was no obvious peak during transition, but at a time after progestin removal equivalent to the time of the oestradiol peak in ewes at mid breeding season, oestradiol concentrations were 6.70 ± 1.14 pg ml⁻¹ in ewes in transition (P < 0.05). In oestradiol treated ewes, peak serum oestradiol concentrations (24.8 ± 2.1 pg ml⁻¹) and time to peak (41.00 ± 0.05 h) did not differ between seasons (P > 0.05). During the breeding season, all six control ewes and four of six ewes given oestradiol showed oestrus with LH and FSH surges. The two ewes not showing oestrus did not respond to oestrus synchronisation and had persistently high serum concentrations of progesterone. During transition, three of six control ewes showed oestrus but only two had LH and FSH surges; all oestradiol treated ewes showed oestrus and gonadotrophin surges (P < 0.05). The timing and magnitude of LH and FSH surges did not vary with treatment or season. In blood samples collected every 12 min for 6 h, from 12 h after the start of oestradiol infusion, mean serum concentrations of LH and LH pulse frequency were lower in control ewes during transition than during mid breeding season (P < 0.05). Oestradiol treatment resulted in lower mean serum concentrations of LH in season and lower LH pulse frequency in transition (P < 0.05). We concluded that enhancing the height of the preovulatory peak in serum concentrations of oestradiol during the breeding season did not alter the timing or the magnitude of the preovulatory surge of LH and FSH secretion and that at transition into anoestrus, oestradiol can induce oestrus and the surge release of LH and FSH as effectively as during the breeding season.     

Expression of angiotensin type 1 and 2 receptors in brain after transient middle cerebral artery occlusion in rats

Angiotensin II (Ang II) type 2 receptors (AT2Rs) have been associated with apoptosis. We hypothesized that AT2Rs are increased in stroke and may contribute effects of stroke to the brain. To test this, we have examined the expression of Ang II type 1 receptor (AT1R), AT2R and Ang II levels in the brain 24 h after transient middle cerebral artery occlusion (MCAO). The densities of AT1R and AT2R were measured by quantitative autoradiography (n=6). The levels of Ang II were measured by radioimmunoassay (RIA) (n=6) and by immunohistochemistry (n=3). AT1R levels on autoradiography showed a significant decrease (0.87±0.06 to 1.39±0.07 fmol/mg, p<0.01) in the ventral cortex of the stroke side compared to the cortices of non-stroke (NS) rats (n=4). There was no significant difference on ATIR in the contralateral verbal cortex of the stroke rats compared to NS control. In contrast, levels of AT2R in the ventral cortex of both the stroke and the contralateral sides were significantly increased (0.77±0.06, p<0.05 and 0.91±0.05, p<0.01 compared to 0.60±0.03 fmol/mg tissue, respectively). RIA showed that Ang II in the ventral cortex of both the stroke and the contralateral sides were significantly increased (241.63±47.72, p<0.01 and 165.51±42.59, p<0.05 compared to 76.80±4.10 pg/g tissue, respectively). Also, Ang II in the hypothalamus was significantly increased (179.50±17.49 to 118.50±6.65 pg/g tissue, p<0.05). Immunohistochemistry confirmed the increase of Ang II. These results demonstrate that brain Ang II and AT2Rs are increased whereas AT1Rs are decreased after transient MCAO in rats. We conclude that in stroke, Ang II and AT2R are activated and may contribute neural effects to brain ischemia.     

Analysis of 8-hydroxydeoxyguanosine among workers exposed to diesel particulate exhaust: comparison with urinary metabolites and PAH air monitoring

Oxidative DNA damage and repair, as measured by 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine and DNA samples were studied in association with work-related diesel exhaust exposure among garage and waste collection workers. Seasonal variations of the urinary 8-OHdG levels in pre- and two post-workshift urine samples of 29 exposed workers and 36 control persons were evaluated. The mean±SE levels of post-workshift 8-OHdG (μmol/mol crea) were 1.52±0.44 in winter and 1.61±0.33 in summer for the exposed workers, and 1.56±0.61 in winter and 1.43±0.49 in summer for the controls, respectively. No significant difference in the urinary 8-OHdG levels between exposed workers and control subjects in winter (p=0.923) and summer (p=0.350) was observed. A linear mixed model, adjusted for years of employment, age, ex/non-smoking and BMI, indicated no significant dose exposure-relationships between the urinary 8-OHdG and 15 PAH air concentrations nor between the 8-OHdG and 7 PAH monohydroxy-metabolites analyzed in the same workers. 8-OHdG was also analyzed in the mononuclear cell DNA of 19 exposed and 18 control subjects. The mean value of 8-OHdG/non-modified 2'-deoxyguanosine (8-OHdG/105 dG±SE) were 4.89±0.17 for the exposed and 4.11±0.16 for the control persons, which showed no correlation with the urinary 8-OHdG levels (r=0.01, n=28, P=0.96). The PAH exposure at workplaces was mainly composed of volatile compounds, particularly naphthalene, suggesting low exposure through the respiratory tract and a low effect of PAH in ROS induction.     

Chronic systemic treatment with epidermal growth factor in the rat increases the mucosal surface of the small intestine

We examined the effects of treatment with human recombinant epidermal growth factor (EGF) on the functioning small intestine in the rat. Male Wistar rats, 7–8 weeks old, were treated with EGF administered subcutaneously in doses of 0 (n = 7) or 150 μg/kg/day (n = 8) for 4 weeks. The histological composition and mucosal surface area of the perfusion-fixed small intestine was quantified with stereological principles. The length of the gut remained unchanged. The amount of tissue and surface area per length of gut (median (ranges)) were increased from 117 (101–131) mg/cm and 2.6 (2.1–3.5) cm²/cm in the controls to 146 (138–152) mg/cm and 3.5 (2.5–3.8) cm²/cm for the complete small intestine (both comparisons p < 0.02). The weight increase was due to mucosal growth in all parts of the intestine, whereas the surface area was only increased in proximal and middle parts. It is concluded that EGF treatment in rats increases the mucosal weight and surface area of the functioning small intestine.     

Evaluation of intra-amniotic surfactant administration for lung maturation in preterm sheep

We aimed to evaluate the effects of intra-amniotic surfactant administration on alveolar lecithin/sphingomyelin ratio, density of type II pneumocytes, and fetal lung function in preterm merino sheep. Pregnant ewes at 119 days gestation either received 200 mg intra-amniotic surfactant (n=4) or saline solution (n=4). After 24 h, the lambs were delivered by hysterotomy and mechanically ventilated. Lecithin/sphingomyelin ratios in alveolar fluid, inflating pressure–volume relationships, and type II pneumocyte counts in histological specimens were compared among the groups. All of the lambs completed the protocol. Mean lecithin/sphingomyelin ratio increased significantly in amniotic (p=0.03) and alveolar fluid (p=0.03) samples of surfactant-treated animals. Lung function in terms of pressure–volume curves did not differ between two groups. Type II pneumocyte density tended to be higher (p=0.057) after intra-amniotic surfactant administration. Single-dose treatment with intra-amniotic surfactant seems to improve amniotic and alveolar lecithin/sphingomyelin ratio questionably by increasing alveolar type II cells. Pressure–volume relationships from inflation of the lungs might be unaltered with intra-amniotic surfactant treatment.     

Ovarian follicular wave synchronization and pregnancy rate after fixed-time natural mating in llamas

The study was designed to compare the efficacy of treatments intended to induce follicular wave synchronization among llamas (Experiment 1), and to determine the effect of these treatments on pregnancy rates after fixed-time natural mating (Experiment 2). In Experiment 1, llamas were treated with: (1) saline (control, n=20); (2) estradiol and progesterone (E/P, n=20); (3) LH (LH, n=20); or (4) transvaginal ultrasound-guided follicle ablation (FA, n=20). The ovarian response was monitored daily by transrectal ultrasonography. The intervals from treatment to follicular wave emergence and to the day on which the new dominant follicle reached ≥7 mm, respectively, did not differ between the LH (2.1±0.3 days and 5.2±0.5 days, respectively) and FA groups (2.3±0.3 days and 5.0±0.5 days), but both were shorter (P<0.05) and less variable (P<0.01) than in the control group (5.5±1.0 days and 8.4±2.0 days), while the E/P group (4.5±0.8 days and 7.7±0.5 days) was intermediate. In Experiment 2, llamas at unknown stages of follicular development were assigned randomly to control, E/P, and LH groups (n=30 per group). A single, fixed-time natural mating was permitted 10–12 days after treatment. Ovulation rates did not differ among groups (control, 93%; E/P, 90%; LH, 90%; P=0.99), but the pregnancy rate was higher (P<0.05) for synchronized llamas (LH and E/P groups combined, 41/54) than for non-synchronized llamas (control group, 15/28). In conclusion, LH and FA treatments were most effective for inducing follicular wave synchronization, while E/P treatment was intermediate. Synchronization treatments did not influence ovulation rate subsequent to fixed-time natural mating, but a higher pregnancy rate in synchronized than non-synchronized llamas warrants critical evaluation of the effects of follicular status on the developmental competence of the contained oocyte.