Radiosensitivity and repair kinetics of gamma-irradiated leukocytes from sporadic prostate cancer patients and healthy individuals assessed by alkaline comet assay

Background: Impaired DNA repair mechanism is one of the main causes of tumor genesis. Study of intrinsic radiosensitivity of cancer patients in a non-target tissue (e.g. peripheral blood) might show the extent of DNA repair deficiency of cells in affected individuals and might be used a predictor of cancer predisposition. Methods: Initial radiation-induced DNA damage (ratio of Tail DNA/Head DNA), dose-response curves and kinetics of DNA repair in leukocytes from healthy volunteers and prostate cancer patients were assessed using alkaline comet assay after exposure to ⁶⁰Co gamma rays. Results: Results showed that higher levels of baseline and gamma rays induced DNA damage in leukocytes of prostate cancer cases than in controls. A similar dose response was obtained for both groups. After a repair time of 24 h following in vitro irradiation, samples from the healthy individuals showed no residual DNA damage in their leukocytes, whereas prostate cancer patients revealed more than 20%. Although similar initial radiosensitivity was observed for both groups, the repair kinetics of radiation induced DNA damage of leukocytes from prostate cancer cases and healthy subjects were statistically different. Conclusion: These results support the hypothesis that men affected by prostate cancer may have a constitutional genomic instability. Key Words: Leukocytes, DNA damage, Radiosensitivity, Prostate cancer, Comet assay     

Pomegranate ellagitannin-derived metabolites inhibit prostate cancer growth and localize to the mouse prostate gland

Our group has shown in a phase II clinical trial that pomegranate juice (PJ) increases prostate specific antigen (PSA) doubling time in prostate cancer (CaP) patients with a rising PSA. Ellagitannins (ETs) are the most abundant polyphenols present in PJ and contribute greatly towards its reported biological properties. On consumption, ETs hydrolyze to release ellagic acid (EA), which is then converted by gut microflora to 3,8-dihydroxy-6H-dibenzo[b, d]pyran-6-one (urolithin A, UA) derivatives. Despite the accumulating knowledge of ET metabolism in animals and humans, there is no available data on the pharmacokinetics and tissue disposition of urolithins. Using a standardized ET-enriched pomegranate extract (PE), we sought to further define the metabolism and tissue distribution of ET metabolites. PE and UA (synthesized in our laboratory) were administered to C57BL/6 wild-type male mice, and metabolite levels in plasma and tissues were determined over 24 h. ET metabolites were concentrated at higher levels in mouse prostate, colon, and intestinal tissues as compared to other tissues after administration of PE or UA. We also evaluated the effects of PE on CaP growth in severe combined immunodeficient (SCID) mice injected subcutaneously with human CaP cells (LAPC-4). PE significantly inhibited LAPC-4 xenograft growth in SCID mice as compared to vehicle control. Finally, EA and several synthesized urolithins were shown to inhibit the growth of human CaP cells in vitro. The chemopreventive potential of pomegranate ETs and localization of their bioactive metabolites in mouse prostate tissue suggest that pomegranate may play a role in CaP treatment and chemoprevention. This warrants future human tissue bioavailability studies and further clinical studies in men with CaP.     

Persistence of Histomonas meleagridis in or on materials used in poultry houses

Histomonas meleagridis is the causative agent of blackhead disease or histomonosis in turkeys, and previous research suggests that this parasite survives poorly outside of hosts except within heterakid nematodes. However, we investigated the viability of H. meleagridis in or on several artificially contaminated materials kept at ambient room temperature (22 +/- 2 C) to mimic the situation in the field. The protozoan survived for up to 1 hr on wood, rubber, and metal; up to 3 hr on egg-tray cartons, egg shells, and bricks; up to 6 hr on straw, turkey feathers, and feed; and up to 9 hr in nonchlorinated tap water and fecal matter. Therefore, contaminated water, fresh fecal matter, or both could play a role in transmission of the parasite within and among poultry houses rather than other materials tested in this study.     

Risk factors for <Emphasis Type="Italic">Mycobacterium avium</Emphasis> subspecies <Emphasis Type="Italic">paratuberculosis</Emphasis> in Fars province (Southern Iran) dairy herds

A cross-sectional study was conducted from March to August 2006 in dairy herds in Fars province, southern Iran to determine the herd-level risk factors for infection with Mycobacterium avium subspecies paratuberculosis (MAP). Statistical analysis using multivariable logistic regression showed that contamination of udders of periparturient cows with manure (OR = 6.4, P = 0.02) and history of having suspected cases of Johne's disease in the herd (OR = 6.7, P = 0.04) were significantly associated with the herd infection status. No relationship between breed, herd size and other management practices with the infection status of the herd were found in this study. Implementing high sanitary measures in the farm, particularly with respect to manure handling and cleaning could be considered as one of the important aspects in controlling disease in the region as well as in the future educational effort.     

Nonmarket Benefits of Reducing Environmental Effects of Potential Wildfires in Beetle-Killed Trees: A Contingent Valuation Study

We estimated Colorado households’ nonmarket values for two forest management options for reducing intensity of future wildfires and associated nonmarket environmental effects wildfires. The first policy is the traditional harvesting of pine beetle-killed trees and burning of the slash piles of residual materials on-site. The second involves harvesting but moving the residual material off-site and converting it into biochar, thus reducing some of the risk and environmental effects associated with burning on-site. A contingent valuation method mail survey was used to evaluate these two management options. The survey achieved a 47% response rate. We used a nonparametric Turnbull estimator to calculate the willingness to pay (WTP) for burn on-site and off-site biochar conversion. The calculated WTP for burn on-site and off-site biochar conversion options (beyond the cost of the status quo level of forest treatment) is $411 and $470 per household per year, respectively.     

Role of mitotic inhibitors and genotype on chromosome doubling of <Emphasis Type="Italic">Rosa</Emphasis>

Dinitroanilines represent a class of compounds that are widely used in herbicide formulations as they depolymerise plant microtubles, causing chromosome doubling. The potential of microtubule depolymerising herbicides trifluralin, oryzalin, and amiprophosmethyl (APM) for in vitro chromosome doubling of Rosa was studied. Five concentrations (0, 3, 6, 12 and 24 μM) and three exposure periods (12, 24 and 48 h) for each of the compounds were compared. Oryzalin, trifluralin and APM were not significantly different in their ability to induce chromosome doubling of R. hybrida cv Iceberg. At concentration of 6 μM and exposure period of 24 h, chromosome doubling of R. hybrida cv Iceberg was not significantly different with each of the polyplodising agents. At higher concentration (24 μM) and longer exposure period (48 h), 66.7% and 62.5% chromosome doubling was achieved with APM and trifluralin, respectively. However, the application of 6 μM oryzalin to R. persica (2n = 2x), R. hybrida cv Iceberg (2n = 3x) and R. hybrida cv Akito (2n = 4x), resulted in 60.0%, 6.3% and 0% chromosome doubling, respectively, which suggest that chromosome doubling is genotype dependent and plants with lower ploidy level have a higher propensity for chromosome doubling. Flow cytometry results at 18 and 24 weeks after herbicide treatment, indicated that the best time to test the treated plants was after 24 weeks.     

Application of synthetic hormone LHRH-A<Subscript>2</Subscript> on the artificial propagation of Persian sturgeon <Emphasis Type="Italic">Acipenser persicus</Emphasis>

For studying the effect of LHRH-A₂ hormone on the induction of final maturation and ovulation of Persian sturgeon, 71 matured females and 20 matured males were used. Five groups of breeders were injected with sturgeon pituitary gland hormone (50 mg per fish) and LHRH-A₂ in dosages of 3.5, 7, 8 and 10 μg kg⁻¹ for females and 3 and 5 μg kg⁻¹ for males. Results showed that LHRH-A₂ successfully induced final maturation and ovulation in females, and there was no significant difference between five groups of breeders in ovulation proportion, fertilization rate, survival rate of incubation, survival of yolk-sac absorption period and active feeding period of larvae. It can be concluded that the LHRH-A₂ is a proper alternative for pituitary gland hormone in artificial propagation of Persian sturgeon.     

Comparison of Growth and Fatty Acids Composition of Freshwater Rotifer, Brachionus calyciflorus Pallas, Fed with Two Types of Microalgae at Different Concentrations

As algae and their concentrations are important factors for mass culture of rotifer, two experiments were conducted to find the effects of two types of algae, Chlorella sp. and Scenedesmus obliquus, and three concentration of chosen algae (0.1 × 10⁶, 1 × 10⁶, and 10 × 10⁶ cells/mL) on growth and fatty acid composition of freshwater rotifer, Brachionus calyciflorus. The result of the first experiment showed that the maximum density of rotifer was significantly higher when fed with Chlorella sp. (478 individuals/mL) than fed with S. obliquus (328 individuals/mL). Mean population growth rate (r) was 0.61 and 0.44 for rotifer fed with Chlorella sp. and S. obliquus, respectively. The amount of highly unsaturated fatty acid (HUFA) in rotifer fed with Chlorella sp. (3.32%) was relatively more than those fed with S. obliquus (2.65%). Then, Chlorella sp. was selected based on better performance. In the second experiment, the maximum rotifer density of 108 ± 8, 489 ± 47, and 493 ± 51 individuals/mL was reached after 5 d for the respective Chlorella sp. concentrations; at concentration of 10 × 10⁶ cells/mL, the maximum density of 1820 ± 47 individuals/mL was obtained. Mean growth rate at mentioned concentrations was 0.18, 0.42, and 0.51/d, respectively. Increase in algal concentration was associated with a relative increase in HUFA and decrease in monounsaturated fatty acid.     

Effects of humic acid on remediation of the nutritional deficiency of gerbera in hydroponic culture

Information is scant on the effect of humic acid (HA) on physiological, antioxidant and photosynthesis attributes of gerbera plants undergoing nutrient deficiency in culture solution. Gerbera plants cv. Malibu were grown in a factorial experiment based on a completely randomized design with 3 replications, using 3 different nutrient solutions [complete nutrient solution (NSc), 25% NSc (NS1), and 50% NSc (NS2)] treated with 2 levels of humic acid [0 (HA0) and 500 mg/l (HA1)].The interaction effect of HA and NS showed that HA improved the flower number in NSc, the transpiration in NS1+HA1, photosynthesis rate in NSc+HA1, stomatal conductance (gs) in NS2, mesophyll conductance of leaves in all NS levels and photosynthetic water use efficiency in NSc+HA1. The interaction effect of nutrient solution and HA on antioxidant activity was inconclusive, malondialdehyde content was the highest in NS2 and the lowest in NS1+HA1. The peroxidase activity increased in complete nutrient solution with and without HA and there were no differences among other treatments. Superoxide dismutase activity increased in NS1 and complete nutrient solution with HA and reached the highest in NSc. Humic acid was more effective in nutrient uptake, i.e., nitrogen, phosphorus, potassium, calcium, zinc, and iron (N, P, K, Ca, Zn, and Fe) in complete nutrient solution compared to NS1 and NS2. Conclusively, humic acid can compensate the nutrient deficiency stress of the culture solution in regards to protein synthesis, photosynthesis attributes regardless of the nutrient uptake of gerbera.