A Bayesian latent variable approach to aggregation of partial and top-ranked lists in genomic studies.

In genomic research, it is becoming increasingly popular to perform meta-analysis, the practice of combining results from multiple studies that target a common essential biological problem. Rank aggregation, a robust meta-analytic approach, consolidates such studies at the rank level. There exists extensive research on this topic, and various methods have been developed in the past. However, these methods have two major limitations when they are applied in the genomic context. First, they are mainly designed to work with full lists, whereas partial and/or top-ranked lists prevail in genomic studies. Second, the component studies are often clustered, and the existing methods fail to utilize such information. To address the above concerns, a Bayesian latent variable approach, called BiG, is proposed to formally deal with partial and top-ranked lists and incorporate the effect of clustering. Various reasonable prior specifications for variance parameters in hierarchical models are carefully studied and compared. Simulation results demonstrate the superior performance of BiG compared with other popular rank aggregation methods under various practical settings. A non-small-cell lung cancer data example is analyzed for illustration.

Effect of exogenous melatonin and different photoperiods on oxidative status and antioxidant enzyme activity in Chhotanagpuri ewe.

AIM: The present study was conducted to evaluate the effect of exogenous melatonin under different photoperiods on oxidative status in Chhotanagpuri ewe. MATERIALS AND METHODS: A total of 42 non-pregnant, non-lactating Chhotanagpuri ewe, having body weight ranging between 14.11±0.09 and 15.38±0.06 kg, were selected and were isolated from rams 2 months before melatonin administration. The selected animals were allocated randomly into seven groups, namely, Group I (normal control), Group II (long day [LD] control), Group III (LD+melatonin administration orally, 3 mg/day), Group IV (LD+melatonin administration subcutaneously, 1 mg/day), Group V (short day [SD] control), Group VI (SD+melatonin administration orally, 3 mg/day), and Group VII (SD+melatonin administration subcutaneously, 1 mg/day) comprising six animals in each group. Rams were then introduced into each group after completion of exogenous administration of melatonin. Blood samples with anticoagulant in vials were collected from each animal day before the start of the experiment and thereafter every month up to 5th month. Hemolysate was prepared for estimation of oxidative stress parameters such as malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT). RESULTS: It was observed that the level of MDA was significantly (p<0.05) higher in LD groups (Group II, III and IV) in comparison to control and SD groups (VI and VII) at 1st month. MDA concentration after exogenous administration of melatonin was significantly (p<0.05) decreased in Group IV and VI in comparison to 1st month. SOD was significantly (p<0.05) higher in SD groups (V, VI, and VII) at the 1st month in comparison to 0 day. After exogenous administration of melatonin, SOD concentration was significantly (p<0.05) higher in Groups III and IV in comparison to 1st month. CAT was significantly (p<0.05) higher in SD groups (V, VI, and VII) in comparison to control and LD groups. After exogenous administration of melatonin, CAT concentration was significantly (p<0.05) higher in Groups III, IV, VI, and VIII in comparison to Groups I, II, and V. At the 3rd month, CAT concentration significantly (p<0.05) decreased in Groups III, IV, VI, and VII in comparison to 2nd month of experiment. However, a decreasing trend of CAT was observed in all the groups from 3rd to 5th month. CONCLUSION: The present experiment revealed that exogenous melatonin was able to reduce significantly the level of MDA and increased the activity of SOD and CAT in Chhotanagpuri ewe.

Effect of temperature variation on hormonal concentration at various gestation stages in black Bengal goat.

AIM: The present study was conducted to evaluate the effect of risingtemperature on the metabolic as well as the reproductive performance of the black Bengal goat. MATERIALS AND METHODS: A total 27 numbers of non-pregnant black Bengal goats of the same parity comprised the experimental animals. The selected goats were randomly assigned to 3 groups of 9 each, maintaining uniformity in body weight (average 14-18 kg). Goats in Group-I were kept between the temperature ranges of 35-40°C, in Group-II between 20°Cand 27°C, and Group-III were kept under loose housing system and serve as a control. Goats in all the groups were bred naturally. Blood was collected prior to feeding in the morning on the day 1 (estrus), 20, 45, 90, and 135, expected day of parturition and also 2 days after parturition from goats of all the three groups. RESULTS: It was observed that the level of plasma estrogen decreased (p<0.05) up to day 45 of gestation, then after increased up to 135 days of gestation and was maximum on expected day of parturition which was significantly (p<0.05) higher than all the values. Plasma progesterone level increased from day 20 and was the highest on day 90 and then decreased significantly (p<0.05) on expected date of parturition. The luteinizing hormone value decreased significantly (p<0.05) on expected day of parturition and day 2 after parturition in all the groups. Follicle stimulating hormone concentration showed a significant (p<0.05) decrease from day 1 to 2 days after parturition in all the groups. The plasma triiodothyronine (T3) level did not vary between and within the treatment groups at any stage of the experiment. The plasma thyroxine (T4) level varied significantly (p<0.01) within and (p<0.05) between groups at all stages of reproduction. A significant (p<0.05) variation in plasma cortisol concentration in all the groups increased significantly until the day of parturition and dropped significantly (p<0.01) in 2 days after parturition in all the groups. CONCLUSION: The present experiment revealed that rise in temperature has no any deleterious effect on the metabolic as well as the reproductive hormonal concentrationat variousstages of gestation inblack Bengal goat.