Effects of Hypo‐ and Hyperthyroidism on Proliferation,Angiogenesis, Apoptosis and Expression of COX‐2 in the Corpus Luteum of Female Rats

Although thyroid dysfunction occurs frequently in humans and some animal species, the mechanisms by which hypo‐ and hyperthyroidism affect the corpus luteum have not been thoroughly elucidated. This study evaluated the levels of proliferative activity, angiogenesis, apoptosis and expression of cyclooxygenase‐2 in the corpus luteum of female rats with thyroid dysfunction. These processes may be important in understanding the reproductive changes caused by thyroid dysfunction. A total of 18 adult female rats were divided into three groups (control, hypothyroid and hyperthyroid) with six animals per group. Three months after treatment to induce thyroid dysfunction, the rats were euthanized in the dioestrus phase. The ovaries were collected and immunohistochemically analysed for expression of the cell proliferation marker CDC‐47, vascular endothelial growth factor (VEGF), VEGF receptor Flk‐1 and cyclooxygenase‐2 (COX‐2). Apoptosis was evaluated using the TUNEL assay. Hypothyroidism reduced the intensity and area of COX‐2 expression in the corpus luteum (p < 0.05), while hyperthyroidism did not alter COX‐2 expression in the dioestrus phase. Hypothyroidism significantly reduced the expression of CDC‐47 in endothelial cells and pericytes in the corpus luteum, whereas hyperthyroidism did not induce a detectable change in CDC‐47 expression (p > 0.05). Hypothyroidism reduced the level of apoptosis in luteal cells (p < 0.05) and increased VEGF expression in the corpus luteum. In contrast, hyperthyroidism increased the level of apoptosis in the corpus luteum (p < 0.05). In conclusion, thyroid dysfunction differentially affects the levels of proliferative activity, angiogenesis and apoptosis and COX‐2 expression in the corpus luteum of female rats.     

Effect of TGF‐β1 Superfamily Members on Survival of Buffalo (Bubalus bubalis) Embryonic Stem‐like Cells

This study examined the effects of supplementation of ES‐like cell culture medium with bone morphogenetic protein (BMP)‐4 (0, 10, 20 or 100 ng/ml) or Noggin (250, 500 or 750 ng/ml) or TGF‐β1 (0, 0.1, 1 or 10 ng/ml) or SB431542 (0, 10, 25 or 50 μm ), an inhibitor of TGF‐β1 signalling, on survival, colony area and expression level of pluripotency genes in buffalo ES‐like cells at passage 40–80, under different culture conditions. BMP‐4 supplementation significantly reduced (p < 0.05) colony survival rate, percentage increase in colony area and relative mRNA abundance of OCT4, whereas that of NANOG and SOX‐2 was increased significantly (p < 0.05). Noggin supplementation did not affect the colony survival rate and percentage increase in colony area in the presence of FGF‐2 and LIF. In the presence of FGF‐2 alone, it significantly reduced (p < 0.05) the relative mRNA abundance of OCT4 and SOX‐2 and increased (p < 0.05) that of NANOG. Supplementation with TGF‐β1 at 1.0 ng/ml but not at other concentrations increased colony survival rate but had no effect on percentage increase in colony area at any concentration. Supplementation with SB‐431542 decreased (p < 0.05) colony survival rate at 50 μm but not at other concentrations. The percentage increase in colony area was lower (p < 0.05) with 10 μm SB‐431542 than that in the controls, whereas at higher concentrations of 25 or 50 μm , SB‐431542 decreased (p < 0.05) the colony size instead of increasing it. In conclusion, these results suggest that BMP‐4 induces differentiation in buffalo ES‐like cells, whereas TGF‐β/activin/nodal pathway may not be playing a crucial role in maintaining pluripotency in these cells.     

Effect of Repeated Stress Treatments During the Follicular Phase and Early Pregnancy on Reproductive Performance of Gilts

In pig husbandry, stress is being considered an important cause of impaired reproductive performance. Therefore, an experiment was performed to quantify effects of repeated stressors during the follicular phase and/or during early pregnancy on reproductive performance of gilts. Eighty-one cyclic gilts were assigned to one of four treatments, namely, stress treatment during the follicular phase (n = 20), stress treatment during early pregnancy (n = 20), stress treatment during both phases (n = 21) and no stress treatment (n = 20). All gilts were housed individually, but gilts in the stress treatments had no opportunity for visual or physical contact with other gilts. Further, animals in a stress-treatment were grouped for half an hour at the start of the treatment and during the treatment period nose-sling and an unpredictable feeding scheme were applied regularly. The extent of stress was monitored using heart rate measurements, behavioural observations and saliva cortisol levels during nose-sling fixation. Of the 81 gilts, 93% showed oestrus and were inseminated. Of these, 93% were pregnant at day 35, having 17.9 +/- 0.3 ovulations and 15.6 +/- 0.3 foetuses. These parameters were not affected by treatment. The stress treatment during the follicular phase tended to shorten cycle length (stress: 20.8 +/- 0.20; control: 21.2 +/- 0.17 days, p = 0.07) and weight of foetuses at day 35 (stress: 4.47 +/- 0.08 g; no stress: 4.69 +/- 0.08 g, p = 0.06); stress during early pregnancy did not affect any of the reproduction parameters. Percentage stereotypic behaviour, heart rate and saliva cortisol levels varied greatly between animals and between days, but did not differ between the treatments. No relationships were found between any of the reproductive parameters and any of the stress parameters (heart rate, cortisol, stereotypic behaviour). These results indicate that the repeatedly applied acute stressors did not generate a chronic stress-response and that these stressors during the follicular phase and/or during early pregnancy did not affect reproductive processes. It is not clear how these findings relate to suggested effects of stress(ors) on reproductive performance in pig husbandry.     

Single-grain 40Ar-39Ar ages of glauconies: implications for the geologic time scale and global sea level variations

The mineral series glaucony supplies 40% of the absolute-age database for the geologic time scale of the last 250 million years. However, glauconies have long been suspected of giving young potassium-argon ages on bulk samples. Laser-probe argon-argon dating shows that glaucony populations comprise grains with a wide range of ages, suggesting a period of genesis several times longer ( approximately 5 million years) than previously thought. An estimate of the age of their enclosing sediments (and therefore of time scale boundaries) is given by the oldest nonrelict grains in the glaucony populations, whereas the formation times of the younger grains appear to be modulated by global sea level.     

Porcine Luteal Function in Relation to IGF-1 Levels Following Ovulation During Lactation or After Weaning

Contents This study presents relationships between peripheral progesterone and Insulin-like Growth Factor-1 (IGF-1) concentrations during the early luteal phase in sows. Data were derived from three experiments, one with primiparous weaned sows (n = 21) and two with multiparous sows that either ovulated during lactation (n = 23) or after weaning (n = 12). The sows that ovulated during lactation did so due to an intermittent suckling regime (inhibition of suckling for 12 h each day from day 14 of lactation) or due to treatment with PG600. IGF-1 concentrations varied considerably among experiments, and were the lowest in the multiparous sows, regardless of whether they were weaned or lactating: 68 ± 5 and 85 ± 8 ng/ml in the two experiments with multiparous sows vs 188 ± 15 ng/ml in the primiparous sows. Progesterone concentrations were lowest for the lactating sows. Overall, the increase in progesterone during the early luteal phase was strongly correlated with IGF-1 concentrations (r = 0.7). However, the correlation was low in multiparous lactating sows (r = 0.28; p < 0.10) and nonsignificant in multiparous weaned sows (r = 0). The weaned multiparous sows had IGF-1 levels comparable to lactating multiparous sows, but higher progesterone levels. In conclusion, these data show a positive relationship between peripheral IGF-1 and progesterone concentrations in vivo during the early luteal phase. In lactating sows, IGF-1 concentrations are probably a limiting factor for progesterone secretion, although other factors may be involved.     

Assessment of Levels and Potential Health Risk of Heavy Metals in Water and Selected Fish Species from the Benue-Niger River Confluence,Lokoja, Nigeria

The concentrations of cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), zinc (Zn), and iron (Fe) in water and selected fish species (Oreochromis nilzinc (oticus and Clarias gariepinus) from Benue-Niger River Confluence, Nigeria were investigated. The water and fish sample digests were quantified using an atomic absorption spectrophotometer. The study aimed to assess any possible human health risk associated with water and fish consumption from the selected geographical area. The concentration of the metals in the surface water ranged from 0.007 to 0.039, 0.106 to 0.240, 0.092 to 0.0164, 0.682 to 0.878, 0.058 to 0.309, and 0.136 to 1.645 mg/L for Cd, Cr, Cu, Fe, Pb, and Zn, respectively, while the concentrations of the metals, Cd, Pb, Cr, Cu, Zn, and Fe in these fish species ranged from 0.034 to 0.679, 0.500 to 1.75, 0.152 to 0.351, 0.36 to 1.01, 5.32 to 7.41, and 4.25 to 9.17 mg/kg, respectively. Cd, Cr, and Pb levels in fish were higher than the provisional tolerable weekly intake of 7, 1.5, and 25 μg/kg bw, respectively, according to the World Health Organization. Dry season values of the metals in water samples were higher, and sharptooth catfish had higher amounts of the metals. The hazard quotient (HQ) for Cd indicated a possible potential health concern with fish consumption from this area.